JP3342199B2 - refrigerator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigerator having a damper device for adjusting the flow rate of cold air to a storage room of a refrigerator, and using a shape memory alloy coil spring as a drive source of the damper device.

[0002]

2. Description of the Related Art A general refrigerator having a freezer compartment and a refrigerator compartment is designed to cool the refrigerator by sending cold air cooled by a cooler in a cooler compartment into a refrigerator compartment through a damper device and a cool air duct. Is configured. Here, the damper device is attached to the inlet portion of the cold air duct, and when the temperature in the refrigerating room rises above the upper limit temperature, the opening of the damper device is opened to perform the cool air circulation to the cold air duct, and the temperature of the refrigerating room becomes the lower limit temperature. When the temperature is lowered to below, the opening is closed and the operation of stopping the flow of the cool air to the cool air duct is performed.

[0003] Examples of the damper device include a gas-filled damper thermostat, a motor-driven motor damper, and a shape memory damper using a shape memory alloy coil spring as a drive source. As a material of the shape memory alloy of this shape memory alloy damper, as shown in FIG. 12, in a cooling process having a large hysteresis width, there are two stages of an intermediate phase (land hedral phase (R phase)) and a martensite phase (M phase). A shape memory alloy having the property of transforming is used, and as the phase transformation, B2 → R → M → B2.

[0004] Such a shape memory alloy damper is disclosed in, for example, Japanese Utility Model Laid-Open Publication No. 3-7582 and Japanese Unexamined Patent Publication No. Hei.
And JP-A-113258. As shown in FIG. 11, the damper device disclosed in these publications has an opening / closing plate (baffle plate) 101 communicating with a cool air duct for sending cool air from the cooler room to the refrigerator compartment, and a rotation of the opening / closing operation of the baffle plate. It consists of a damper base 102 with a fixed shaft and mounted in a cold air duct. Then, a DC voltage Vcc (for example, DC 12 V) is applied from a DC power supply 106 to a heater 104 wound around a spiral shape memory alloy coil spring 103 as shown in FIG. 14 and subjected to an insulation treatment (single-layer covering layer) on the surface. By doing so, the shape memory alloy coil spring 103 is directly heated.

Here, the shape memory alloy coil spring 103
Is the austenite phase transition end temperature Af (hereinafter simply Af
When heated for more than a point, the contraction force is generated by the shape memory effect of restoring the stored original shape. In FIG. 14, one end of the shape memory alloy coil spring 103 is attached to the baffle plate 101.
The remaining one end is hooked on the damper base 102, and the baffle plate 101 and the damper base 102 have a direction opposite to the direction in which the baffle plate rotates due to the contraction force of the shape memory alloy coil spring 103 (that is, the direction opposite to the direction in which the baffle plate opposes). ) To bias the baffle plate to
5 is hooked. In addition, A of the shape memory alloy coil spring
It is necessary to set the contraction force at or above the point f larger than the biasing force of the bias spring 105.

The operation of this damper device will be briefly described. First, when the refrigerator is cooled, the contraction force at the point Af or higher is set to be larger than the biasing force of the bias spring 105. By energizing 104 and heating the shape memory alloy coil spring 103 to the point Af or higher, the shape memory alloy coil spring is contracted to the stored original shape. Due to this contraction force, the damper baffle plate 101 is lifted to open the opening of the cool air duct (specifically, the damper base). As a result, cool air flows from the cooler room into the refrigerator room to cool the refrigerator room.

Next, in order to stop the flow of the cool air to the refrigerator compartment, the application of the DC voltage Vcc is stopped to stop the energization of the heater 104, and the shape memory alloy coil spring is cooled by the cool air around the damper device to the martensitic phase. Cool below the transition temperature Mf (hereinafter simply referred to as the Mf point), release the contraction force of the shape memory alloy coil spring, or pull down the damper baffle plate with the biasing force of the bias spring to lower the opening of the cool air duct (specifically, the damper base). close. As a result, the flow of cool air from the cooler room into the refrigerator compartment stops, and the cooling of the refrigerator compartment stops.

The installation place of such a damper device is such that the cool air blown by a fan from the cooler room is -20 to-.
It reaches 25 ° C. Shape memory alloys are B2 → M, M →
Operates in B2 transformation, but the cold air at -20 to -25 ° C is Mf
Since the temperature is lower than the point, when the power supply is stopped, the shape memory alloy coil spring that has been heated to 70 ° C. or higher is rapidly cooled and deformed by the force of the bias spring, resulting in severe conditions for the shape memory coil spring. Will be used in. Also, the distortion of the shape memory alloy coil spring increases. For this reason, it is unsuitable for application to refrigerators that are required to open and close beyond the durability limit (200,000 times of durability) as a damper device.

Further, since the present method is a method of heating the shape memory alloy coil spring while depriving the heat of the cool air, in order to overcome the biasing force of the bias spring and open the baffle plate, the heating is performed without blowing the cool air. It is necessary to increase the amount of heat generated by the heater as compared with the case where the power consumption is increased, which is uneconomical in terms of power consumption.

On the other hand, Japanese Patent Application Laid-Open No.
In the damper device disclosed in Japanese Patent No. 1640, an opening / closing plate (baffle plate) having an opening communicating with a cool air duct for sending cool air from a cooler room to a refrigerator room and a rotating shaft for opening / closing the baffle plate are fixed. And a damper base mounted in the cool air duct.

However, as shown in FIG. 12, the damper device of this application and the above-mentioned conventional device differ in the manner of mounting two springs and the method of energizing the heater. That is, the damper device is configured such that a bias spring 44 for urging the baffle plate 43 in the opening direction and a heater 46 for heating are restored to the original shape when the heater 46 is wound and heated to a temperature equal to or higher than the austenite phase transition end temperature. And a control device for controlling the energization of the heater by energizing the heater to close the opening / closing plate, and closing the opening / closing plate by closing the opening / closing plate. In the open state, a small current is applied to the heater so as to maintain the temperature of the shape memory alloy coil spring at or above the martensite phase transition start temperature.

In the damper device disclosed in Japanese Patent Application Laid-Open No. 6-241640 , durability and distortion, which were problems in the prior art, have been drastically improved and power consumption has been reduced. However, a minute current is continuously supplied to the heater to maintain the temperature of the shape memory alloy coil spring at a temperature equal to or higher than the Mf ′ point and equal to or lower than the Af point.
Considering the outside air temperature, the load of the refrigerating room or freezing room, the variation of the resistance value of the heater, the voltage variation of the constant voltage circuit, etc.
It is difficult to maintain the temperature above the Mf ′ point and below the Af point only by passing a small current, and it is difficult to execute appropriate control.

When the refrigerator is cooled, that is, when the damper baffle plate is in the open state, a small current is supplied. When the refrigerator is installed, a small current is similarly supplied. When this refrigerator is installed, the box (especially the refrigerator compartment) is at room temperature. Therefore, even if the wind flows through the cold air duct to send cold air to the refrigerator compartment, the temperature does not drop rapidly, and the surroundings of the damper ( In particular, the temperature of the shape memory alloy coil spring) does not decrease so rapidly. In addition, since a minute current flows through the heater, the temperature of the shape memory alloy coil spring is easily stabilized at a temperature equal to or higher than the Mf 'point and equal to or lower than the Af point. As a result, the temperature of the shape memory alloy coil spring does not easily drop to a desired temperature even when the damper device (specifically, the opening / closing plate) is to be maintained in a fully opened state at the time of installation requiring the most amount of cool air. The opening / closing plate stops when the force relationship between the coil spring and the bias spring is balanced (a position between the fully open position and the fully closed position), and the open / close plate cannot be fully opened. In the time immediately Chi installation can not reduce the temperature of the refrigerating compartment to quite the desired temperature, the cooling rate was a likely slow problem. This is the same not only at the time of installation but also in a state in which the operation returns to the cooling operation.

Further, as described above, the shape memory alloy coil spring is constituted by an invalid winding portion which is attached to the hook and is not attached to the hook and which is not extended and contracted, and an effective winding portion which is continuously extended and contracted from the invalid winding portion. . The heater wound around the shape memory alloy coil spring and having its surface subjected to insulation treatment is wound only around the effective winding portion of the shape memory alloy coil spring, and fixes the shape memory alloy coil spring to the opening / closing baffle plate and the damper base. It is not wound on the invalid winding portion attached to the hook. For this reason, the temperature distribution of the shape memory alloy coil spring when the heater is energized is such that the temperature of the invalid winding portion is the lowest because there is an invalid winding portion where the heater is not wound at both ends, and the shape of the shape distribution because the heater is wound. The center of the effective winding of the memory alloy coil spring has the highest temperature, and the temperatures of both ends of the effective winding are higher than the invalid winding and lower than the center.

At the time of heating (especially at the time of the maximum heater current), the central portion having a high temperature quickly recovers (shrinks) to the original shape stored therein. It is quickly cooled and becomes a martensite state (a state in which the contracting force is released). For this reason, in the heating and heat retaining cycle, the amount of expansion and contraction at both ends of the effective winding portion is large, and the amount of expansion and contraction is the smallest at the center portion. As a result, stress is frequently applied only to both end portions of the effective winding portion and effective winding is performed. This causes a problem at both ends of the portion, which is a problem.

In addition, as shown in FIG. 14, the shape memory alloy coil spring is attached to the opening / closing baffle plate and the damper base by an insulated fixture 65 (the above-mentioned hook) such as a laminated plate. Generally, both ends of the shape memory alloy coil spring are held through holes formed in the fixture. Due to restrictions on the material strength of the laminate and the accuracy of the mold, a hole for fixing is formed at a position of about 1 to 2 mm from the end face of the laminate (fixing tool). Hand, the shape memory alloy coil spring is to be stored shape in close contact with the whole of the effective winding portion is common. In fact, when this shape memory alloy coil spring is incorporated as a damper, the end of the effective winding portion of the shape memory alloy coil spring hits the laminated plate as a fixed portion each time it opens and closes (specifically, when it shrinks due to the austenite state), resulting in This also corresponds to the heater wound around the effective winding portion of the shape memory alloy coil spring. This ensures that becomes shorting the DC voltage across the heater wire peel off the covering layer of the heater, which is insulated is touching the shape-memory alloy coil spring shape memory alloy itself becomes conductive, lead wire and laminates There was a problem causing scorching. Further, in a severe case, the heater is disconnected and the shape memory alloy coil spring cannot be heated, so that the baffle plate cannot be closed.

Further, the shape memory alloy coil spring of the heater 104 shown in FIG. 14 has a problem that the heater lead portion 107 from the winding end to the electrode is twisted and kink during assembling processing, causing disconnection during use.

Therefore, in the present invention, -20 like a refrigerator is used.
It is excellent in usability and durability in a low temperature range of about ℃, can prevent disconnection of the heater wound around the shape memory alloy coil spring and peeling of the surface coating layer, and can uniformly expand and contract the shape memory alloy coil spring. It is intended to provide a refrigerator.

[0019]

The refrigerator according to the present invention has a function of -2.
In order to improve the usability and durability in a low temperature range of about 0 ° C., a cold air duct that guides the cool air cooled by the cooler to the storage room, and a damper device that controls the flow of the cool air into the cool air duct are provided. The damper device includes a case having an opening communicating with the cold air duct, an opening / closing plate rotatably supported by the case to open and close the opening, and a bias spring biasing the opening / closing plate in the opening direction. A shape memory alloy coil spring that recovers its original shape when the heater for heating is wound and is heated to a temperature equal to or higher than the austenite phase transition end temperature and closes the opening / closing plate against the biasing force of the bias spring. A ternary alloy having no intermediate phase is used for the shape memory alloy coil spring.

In order to prevent the heater wound around the shape memory alloy coil spring from being disconnected and the surface coating layer from peeling off, the shape memory alloy coil spring of the present invention has an effective winding portion that expands and contracts and an invalid winding portion that does not expand and contract. And a refrigerator in which the original shape of the effective winding portion is different between the central portion and the both end portions.

[0021] For the same purpose, the original shape of the effective winding portion to be recovered is to provide a refrigerator in which the central portions are in close contact with each other and the one-turn portions at both ends are separated from the central portion. is there.

Further, for the same purpose, the refrigerator of the present invention comprises:
A cool air duct that guides the cool air cooled by the cooler to the storage room,
A damper device for controlling the flow of cool air into the cool air duct is provided, the damper device has a case having an opening communicating with the cool air duct, and an opening / closing plate pivotally supported by the case to open and close the opening. A bias spring that urges the opening / closing plate in the opening direction, and an insulated heating heater that is wrapped and recovers its original shape when heated above the austenite phase transition end temperature, and the biasing force of the bias spring The present invention provides a refrigerator comprising a shape memory alloy coil spring for closing the opening / closing plate against the above, wherein the heater is provided with a fluororesin layer outside an insulating layer.

On the other hand, in order to uniformly expand and contract the shape memory alloy coil spring, there is provided a refrigerator in which the effective winding portion of the shape memory alloy coil spring has a maximum diameter at the center portion and gradually decreases toward both end portions. Things.

For the same purpose, according to the present invention, the central portion of the heater is wound in a loosely wound state with a gap therebetween, and the heater is wound tightly in close contact with each other as the heater approaches the portions corresponding to both ends of the shape memory alloy coil spring. Is to provide a refrigerator.

For the same purpose, according to the present invention, the winding diameter of the heater is such that the central portion corresponding to the central portion of the shape memory alloy coil spring is sufficiently larger than the diameter of the shape memory alloy coil spring.
An object of the present invention is to provide a refrigerator having a shape memory alloy coil spring having a diameter substantially the same as a diameter of the shape memory alloy coil spring as it approaches both end portions corresponding to both end portions of the shape memory alloy coil spring.

[0026]

[0027]

[0028]

[0029]

[0030]

[0031]

SUMMARY OF] According to the present invention, the heater because the both end portions in the open coiled center portion has a closed winding, the heat transfer from the heater as the central portion of the effective winding portion of the shape memory alloy coil spring As the temperature decreases, the temperature rise of the coil spring is slow and the temperature is kept low. On the other hand, the closer to both ends of the effective winding portion, the greater the amount of heat transfer from the heater, and the faster the temperature rises at both ends. For this reason, the temperature difference between the both end portions and the center portion from the start of heating as in the prior art does not occur, and the difference does not gradually open during heating, and the effective winding portion of the coil spring in the coil contraction operation does not occur. The temperature distribution is made uniform (that is, the temperature rise during heating can be made uniform), and the temperature at both ends becomes higher than the temperature at the center at the end of heating. On the other hand, at the time of cooling, the temperature at both ends is high, so that both ends are cooled from a state where the temperature at both ends is low and the both ends do not start to elongate as in the conventional case, and can be uniformly cooled. Therefore, when considered throughout the repetition of heating and cooling, an apparently uniform force is applied to the effective winding portion, and the occurrence of distortion due to force concentration in a part (particularly, both end portions) of the effective winding portion is suppressed. Thus, the durability of the coil spring is improved.

According to the second aspect of the present invention, the center diameter of the heater corresponding to the center of the shape memory alloy coil spring is sufficiently larger than the diameter of the shape memory alloy coil spring, and the winding diameter of the heater corresponds to both ends of the shape memory alloy coil spring. The distance between the heater and the coil spring is the largest at the center and the smallest at both ends because the shape of the coil is approximately the same as the diameter of the shape memory alloy coil spring as it approaches the ends. For this reason,
Heat transfer from the heater becomes worse at the center of the effective winding portion of the shape memory alloy coil spring, and the temperature rise of the coil spring is slow and the temperature is kept low. On the other hand, the heat transfer from the heater becomes better near the both ends of the effective winding portion. Therefore, the temperature at both end portions rises quickly and the temperature rises. For this reason, there is no such gradually opened gradually and the difference in heating temperature difference occurs between the conventional end portions and the central portion of the heating start time as the effective winding portion of the coil spring in the coil contraction operation (Ie, the temperature rise during heating can be made uniform), and the temperature at both ends becomes higher than the temperature at the center at the end of heating. On the other hand, at the time of cooling, the temperature at both ends is high, so that both ends are cooled from a state where the temperature at both ends is low and the both ends do not start to elongate as in the conventional case, and can be uniformly cooled. What slave, uniform becomes a force is exerted on the apparent relative effective winding portion Considering through repeated total heating and cooling, the occurrence of distortion due to the force concentration at the part of the effective winding portion (particularly end portions) It is suppressed, and the durability of the coil spring is improved.

[0033]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 1 is a longitudinal sectional side view of the refrigerator, FIG. 2 is an enlarged sectional view around the damper device in a state where the damper device is arranged at an inlet of a cold air duct of a refrigerator, and FIG. 3 is an exploded perspective view of the damper device. FIG. 4 is a stress-temperature characteristic diagram of a shape memory ternary alloy (Cu, Ti, Ni) coil spring used in the present invention. FIG. 5 is an effective winding of the shape memory alloy coil spring of the damper device of the present invention. 1 at both ends of the part
FIG. 6 is a diagram showing a state in which a gap is provided in a turn portion (austenitic shape), and FIG. 6 shows a state in which the winding diameter of the shape memory alloy coil spring of the damper device of the present invention is stored in different shapes at the center portion and both end portions. (Austenitic shape), FIG. 7 is a sparse and dense winding diagram of a heater provided with an insulating coating before being wound around a shape memory alloy coil spring of the present invention, and FIG. 8 is attached to a damper device of the present invention. FIG. 9 is a processing diagram showing a state in which a heater having an insulating coating provided thereon has a different winding diameter and is densely and densely wound. FIG. 9 shows a state in which a heater having an insulating coating provided is wound around a shape memory alloy coil spring having a different winding diameter. FIG. 10 is a perspective view of a state in which the heater is wound around a shape memory alloy coil spring, attached to a fixing member, and both ends of the heater are connected to terminals.

In FIG. 1, 1 is a home refrigerator,
The refrigerator 1 includes a heat insulating box 2 having a cross section of a front opening constituting a main body thereof, and doors 3, 4, and 5 for closing the opening of the box. The door 3 is a pivotable door corresponding to a refrigerator room 13 described later, the doors 4 and 5 are draw-out doors, the door 4 corresponds to the freezing room 14, and the door 5 corresponds to the vegetable room 15. ing.

Reference numerals 11 and 12 denote horizontal partition walls which partition the interior of the heat insulating box 2 into three stages of upper, middle and lower. In this embodiment, the partition walls 11 are used.
Refrigerator 13 is cooled to a temperature at which food does not freeze (for example, about 3 ° C.), a freezing chamber 14 is cooled above the partition 12 to a freezing temperature (for example, about −20 ° C.), and partition 1
2 is cooled to a temperature (for example, about 7 ° C.) suitable for storing vegetables slightly lower than the temperature of the refrigerator compartment 13 below the refrigerator compartment 13.
5 is assumed. The door 4 is provided with a container 16 for storing frozen food, and the door 5 is provided with a container 17 for storing vegetables.

A partition plate 18 is disposed at the back of the freezer compartment 14. Behind the partition plate 18, a plate fin type evaporator 19 as a cooler and a blower 20 such as a propeller fan are provided.
Is formed.

Numeral 22 denotes a freezing air duct for supplying the cold air cooled by the evaporator 19 from the outlet 22A to the freezing compartment 14. Numeral 23 denotes the cold air passing through the horizontal partition wall 11 and cooled by the evaporator 19. Is a refrigeration air duct for supplying refrigeration to the refrigeration compartment 13, and 24 is a distribution refrigeration air duct for communicating with the refrigeration compartment refrigeration air duct 23 and distributing the refrigerated air from the outlets 24A and 24B to the refrigeration compartment. . Numeral 25 denotes a damper device which is a so-called shape memory alloy damper disposed at a connection portion between the cold air duct 23 for cooling and the cold air duct 24 for distribution.

A machine room 33 in which a compressor 31 and an evaporating dish 32 are arranged is formed below and behind the heat insulating box 2. Reference numeral 35 denotes a dew tray disposed below the evaporator 19, and reference numeral 36 denotes a defrosting heater such as a quartz glass tube heater or a Vycor tube heater disposed between the dew tray 35 and the evaporator 19. In addition, a platinum-based ceramic deodorizing catalyst is laminated and fired on the surface of the glass tube of the heater 36 for defrosting. This defrost heater 36 allows the compressor 3
At the time of the operation 1 (that is, at the time of the cooling operation), the odor component of the cool air including the odor component returning below the evaporator 19 is adsorbed,
Heat can be exchanged with the evaporator as clean cool air, and when the defrost heater is operated (that is, during the defrost operation), the adsorbed odor component is oxidized and decomposed with a platinum-based catalyst to form a catalyst layer. Activation and clean air can be generated.

Reference numeral 37 denotes the horizontal partition wall 12 extending from the cold air inlet 37A formed at the front of the lower surface of the horizontal partition 12 to the return port 37B formed at the rear of the partition 12 and below the evaporator. It is a cold air return passage extending inside in the front-rear direction. Reference numeral 38 denotes a water distribution pipe for guiding defrost water from the dew receiving tray 35 to the evaporating dish.

As shown in FIGS. 2 and 3, the damper device 2
Reference numeral 5 denotes a transparent resin case 42 having an opening 41 communicating with the distribution cool air duct 24, an opening / closing plate 43 pivotally supported by the case 42 to open and close the opening 41, and opening and closing the opening / closing plate 43. A bias spring 44 biasing in the direction, and a heater 45 such as a heating kanthal heater having an insulating coating layer formed on its surface are wound around the austenitic phase transition ending temperature.
(Af point) A shape memory alloy coil spring 46 that recovers the original shape stored when heated above this point and closes the opening / closing plate 43 against the biasing force of the bias spring 44.

The case 42 includes a substrate 51 and a cover 52. The substrate 51 has an opening 41, a through hole 53 facing a part of the opening / closing plate 43, a rib 54 formed in a peripheral portion of the through hole to support the opening / closing plate 43, and two holes formed in a cover 52. An insertion hole 55 for inserting the two claw portions 58 and a fixing portion 56 for fixing one end of the shape memory alloy coil spring 46
And 57 for fixing one end of the bias spring 44. The cover 52 is formed in a container shape with one surface opened, and two claw portions are formed on the periphery of the opening, and a hole 59 for taking in air is formed on the other surface facing the opening.

The opening / closing plate 43 includes two shafts 61 supported by the ribs 54 of the substrate 51, a fixing portion 62 for fixing the other end of the shape memory alloy coil spring 46, and a fixing portion for fixing the other end of the bias spring 44. A portion 63 and a sealing member 64 such as polystyrene foam for sealing the opening 41 and the opening / closing plate 43 when the opening 41 is closed.

Both ends of the shape memory alloy coil spring 46 are fixed to fixing portions 56 and 62 via fixing members 65 by means of tools 60 such as screws. To each fixing member 65, a fixing terminal (terminal) 67 for connecting one end of the heater 45 and connecting a lead wire is attached.
5 is electrically connected to the fixed terminal 67 by crimp welding.

Next, the shape memory coil spring 46 made of a ternary alloy (Cu, Ti, Ni in this embodiment) used in the present invention will be described.

The ternary alloy used in the present invention is made of three raw materials of Cu, Ti and Ni, and has a stress-temperature characteristic of a shape using a conventional binary alloy (Ti, Ni) as shown in FIG. Unlike the characteristics of the memory alloy coil spring, there is no intermediate phase (R phase) in the cooling process of the alloy. In the present invention, as a specific example, the austenite phase transition end temperature Af
Austenite phase transition onset temperature As point (hereinafter simply referred to as As point) 40.1 ° C, martensite phase transition onset temperature Ms point (hereinafter simply referred to as Ms point) 38.8 ° C,
A martensitic phase transition end temperature Mf point (hereinafter, simply referred to as Mf point) uses a shape memory alloy having a temperature characteristic of 17.6 ° C.

In particular, a Cu content of 47.5 to 47.8% by weight of Ni, 7.0 to 9.0% by weight of Cu, and 43.1 to 45.5% by weight of Ti (that is, the remaining components) in the whole.
NiTi ternary alloy.

According to the coil spring 46, since a ternary alloy having no intermediate phase is employed as the stress-temperature characteristic, the austenite phase transition end temperature Af and the martensite phase are compared with those of a conventional binary alloy coil spring having an intermediate phase. In order to improve the responsiveness in a low-temperature atmosphere, that is, to maintain the coil spring at an intermediate phase temperature in order to improve the responsiveness in a low-temperature atmosphere, that is, to reduce the difference from the site phase transition end temperature Mf. In addition, unlike the related art, there is no need to constantly supply a small current, and the power consumption of the heater 45 can be reduced. In addition, a large amount of cold air needs to be supplied to the refrigerator compartment when the refrigerator is installed or when the cooling operation is resumed, so that the responsiveness when the opening / closing plate 43 is fully opened is improved. For this reason, the usability and durability of the damper device 25 in a low temperature range are significantly improved as compared with the conventional binary alloy.

The shape memory alloy coil spring 46 of the damper device 25 has an invalid winding portion 46A attached to the fixing member 65 and not expanding and contracting.
And an effective winding portion 46B which extends and contracts.

By changing the original shape (ie, austenite shape) of the effective winding portion 46B to be different between the central portion 46Bb and both end portions 46Ba, both end portions 46Ba of the effective winding portion 46B (actually, this effective Since the heater 45 is wound around the winding portion 46B, the heater 45
Of the shape memory alloy coil spring 46 when the end portions 45B) of the shape memory alloy coil spring 46 are contracted.
It becomes easy to select a position where it is difficult to contact the fixing member 65 for fixing A.

As an example in which the effective winding portion 46B and the invalid winding portion 46A are formed in different shapes, as shown in FIG. 7, for example, both end portions (particularly, one turn portion) 4 of the effective winding portion 46B.
The shape is memorized so that a gap is left only in 6Ba, and the portions other than both ends (that is, the center portion of the effective winding portion) 46Bb are memorized in a shape in which they are in close contact with each other. As the gap here, a distance corresponding to the distance from the mounting hole of the fixing member 65 to the end face (that is, the mounting allowance), for example, about 1 mm,
Has been selected.

According to this example, if the heater 45 is wound around only the central portion 46Bb of the effective winding portion 46B, when the effective winding portion 46B contracts, both end portions 46Ba of the effective winding portion become the central portion 46Bb. Do not contact with Therefore, when the heaters 45 come into contact with each other by the expansion / contraction operation of the shape memory alloy coil spring 46 or when the heater and the coil spring come into contact with each other, the coating layer of the heater 45 wound around the coil spring 46 is peeled off, or the heater wire itself is disconnected. The trouble to do was gone. Moreover, the size of the effective winding portion of the coil can be reduced as compared with a case where a gap is provided between adjacent portions of the entire coil spring.

Incidentally, regardless of the austenitic shape of the coil spring, the insulating layer of the heater 45 is prevented from peeling or breaking.
The heater having the insulating coating layer is connected to the shape memory alloy coil spring 46.
(See FIG. 9), the coil spring is immersed in a tank containing a liquid fluororesin, for example, a solution of ethylene tetrafluoride, to provide a fluororesin layer on both surfaces of the coil spring and the heater. Since both surfaces are coated with fluorocarbon resin, the strength of the heater against friction and rubbing between the coil spring and the heater increases, the insulating coating layer of the heater does not easily peel off, and the insulating layer peels off or breaks due to expansion and contraction of the coil spring. And the insulating coating layer can be formed on the surface of the coil spring, so that electrical insulation between the heater and the coil spring is ensured.

On the other hand, some embodiments will be described below for measures for suppressing local concentration of force during heating and cooling of the coil spring. However, even if local concentration of force is suppressed, force tends to concentrate at the center of the effective winding during heating, and tends to concentrate at both ends during cooling. This means that an apparently uniform force is applied to the effective winding portion.

The shape memory alloy coil spring 146 is different from the shape shown in FIG. 8 in that the original shape of the effective winding portion 146B (ie, the austenite shape) is different between the central portion 146Bb and both end portions 146Ba. In particular, the winding diameters at both end portions and the central portion are made different. That is, the winding diameter of the central portion 146Bb is increased and both end portions 1
By reducing the winding diameter of 46Ba, the winding diameter is changed so that the winding diameter gradually decreases as the central portion becomes largest and approaches the both end portions.

According to this example, the winding diameter of the effective winding portion 146B is the largest at the central portion 146Bb,
The force required for expanding and contracting the effective winding portion 146B is gradually reduced toward the center portion Ba.
6Bb is small and both end portions 146Ba are large, and the length of the coil wire is such that the central portion 146Bb is long and both end portions 146Ba are short. At the time of heating where the temperature of the central portion of the effective winding portion 146B becomes high first and is likely to shrink, the length of the central portion becomes long, so that the heat capacity of the central portion becomes large and the temperature rise is suppressed, and the temperature is uniformly reduced as a whole. During cooling, when the temperature of the both ends of the effective winding portion 146B is lowered first and the stretch is easy to expand, the force at both ends becomes stronger than that at the center, so that the settling due to expansion and contraction at both ends can be suppressed. For this reason, the expansion and contraction characteristics and the temperature distribution during heating and cooling of the effective winding portion were easily apparently uniform.

As another embodiment, FIG. 5 shows a sparse and dense winding process of a kanthal heater 45 before being wound around a shape memory alloy coil spring 46. The winding diameter of the Kanthal heater 45 is slightly larger than the wire diameter of the shape memory alloy coil spring. The heater 45 includes lead portions 45A at both ends, both end portions 45B which start and end winding continuously from the lead portion 45A, and a central portion 45C therebetween. The end of the lead portion 45A is connected to a fixed terminal (terminal) 67 attached to the fixing member 65. Then, the both end portions 45B are processed so as to be tightly wound with a narrow space between the lines, and the central portion 45C is processed so as to be loosely wound with a wide space between the lines. In FIG. 5, the heaters are sequentially wound at different intervals so that the center is the most sparse winding and the both ends are the tightest winding.

According to this example, the heater 45 is connected to the central portion 4.
Since 5C is loosely wound and both end portions 45B are densely wound, the length of the heater becomes shorter as the central portion 46Bb of the effective winding portion 46B of the shape memory alloy coil spring 46 becomes shorter.
5, the amount of heat transfer from the coil spring 5 becomes small, and the temperature rise of the coil spring is slow and the temperature is kept low. In addition, the effective winding portion 46
The closer to both ends 46Ba of B, the longer the length of the heater, the greater the amount of heat transferred from the heater, and the faster the temperature at both ends is, the higher the temperature.

As a result, the temperature difference between the both end portions 46Ba and the central portion 46Bb from the start of heating as in the prior art, and the difference does not gradually open during heating is eliminated, and the contraction operation of the coil spring 46 is prevented. In this case, the temperature distribution of the effective winding portion 46B of the coil spring is made uniform (that is, the temperature rise of the effective winding portion 46B during heating can be made uniform), and at the end of heating, the temperature of both end portions 46Ba becomes the central portion 46Bb.
Temperature higher than the temperature of Hand, since the cooling time is high temperature end portions 46Ba, never both end portions as in the prior art begins extending first been cooled temperature at both ends from a low state, can be uniformly cooled. Therefore, considering the entire heating and cooling cycle, the effective winding 4
6B, an apparently uniform force is applied to a portion of the effective winding portion 46B (particularly, both end portions 46Ba).
Is suppressed, and the durability of the coil spring 46 is improved.

As another example, as shown in FIG. 6, the winding diameter of the Kanthal heater 145
5B has the same or slightly larger size (substantially the same size) as the wire diameter of the coil spring 46, and the central portion 145C has a size sufficiently larger than the wire diameter of the coil spring 46. However, FIG.
Is processed so that the winding diameter gradually increases from both ends toward the center.

According to this example, the winding diameter of the heater 145 is such that the central portion 145C corresponding to the central portion of the shape memory alloy coil spring 46 is sufficiently larger than the diameter of the coil spring, and both end portions corresponding to both end portions of the shape memory alloy coil spring. 145
The distance between the heater 145 and the coil spring 46 is the largest at the center and the smallest at both ends as it approaches B. For this reason, heat transfer from the heater becomes worse in the central portion 46Bb of the effective winding portion 46B of the shape memory alloy coil spring, and the temperature rise of the coil spring is slow and the temperature is kept low. On the other hand, the heater becomes closer to both ends 46Ba of the effective winding portion. 14
5 and the temperature of the both ends 46Ba rises quickly and the temperature rises.

For this reason, at the time of heating, the temperature rise in the central part can be suppressed as compared with the conventional case, and the temperature rise in both ends can be promoted.
At the time of cooling, the temperature drop at both ends can be suppressed and the temperature drop at the center can be promoted. As a result, when considered throughout the repetition of heating and cooling, the effective winding portion is apparently uniformly temperature-changed and a uniform force is applied, and the force in a part (particularly, both end portions) of the effective winding portion is applied. Generation of distortion due to concentration is suppressed, and the durability of the coil spring is improved.

As shown in FIG. 10, if the ternary alloy coil spring is made to have a different memory shape and a different winding method and a different winding method of the heater, the heater wire is cut off due to a synergistic effect of the respective effects. The temperature distribution of the coil spring is more uniform, and the local distortion of the coil spring can be prevented and suppressed. The durability of the coil spring can be dramatically improved, and the low-temperature characteristics can be improved. Therefore, it is suitable for application to a refrigerator damper device. is there.

[0063]

[0064]

[0065]

[0066]

[0067]

[0068]

Effects of the Invention According to the present invention, the heater because the both end portions in the open coiled center portion has a closed winding, the heat transfer from the heater as the central portion of the effective winding portion of the shape memory alloy coil spring While the amount is small, the temperature rise of the coil spring is slow and the temperature is kept low. On the other hand, the closer to both ends of the effective winding portion, the larger the amount of heat transfer from the heater, and the faster the temperature rises at both ends, so that the temperature can be raised. For this reason, the temperature difference between the both end portions and the center portion from the start of heating as in the prior art does not occur, and the difference does not gradually open during heating, and the effective winding portion of the coil spring in the coil contraction operation does not occur. The temperature distribution is made uniform (that is, the temperature rise during heating can be made uniform), and the temperature at both ends becomes higher than the temperature at the center at the end of heating. On the other hand, at the time of cooling, the temperature at both ends is high, so that both ends are cooled from a state where the temperature at both ends is low and the both ends do not start to elongate as in the conventional case, and can be uniformly cooled. Therefore, when considered throughout the repetition of heating and cooling, an apparently uniform force is applied to the effective winding portion, and the occurrence of distortion due to force concentration in a part (particularly, both end portions) of the effective winding portion is suppressed. Thus, the durability of the coil spring is improved.

According to the second aspect of the present invention, the winding diameter of the heater is such that the central portion corresponding to the central portion of the shape memory alloy coil spring is sufficiently larger than the diameter of the shape memory alloy coil spring, and corresponds to both ends of the shape memory alloy coil spring. The distance between the heater and the coil spring is the largest at the center and the smallest at both ends because the shape of the coil is approximately the same as the diameter of the shape memory alloy coil spring as it approaches the ends. For this reason,
Heat transfer from the heater becomes worse at the center of the effective winding portion of the shape memory alloy coil spring, and the temperature rise of the coil spring is slow and the temperature is kept low. On the other hand, the heat transfer from the heater becomes better near the both ends of the effective winding portion. The temperature rises quickly at both ends, and the temperature can be increased. For this reason, there is no such gradually opened gradually and the difference in heating temperature difference occurs between the conventional end portions and the central portion of the heating start time as the effective winding portion of the coil spring in the coil contraction operation (Ie, the temperature rise during heating can be made uniform), and the temperature at both ends becomes higher than the temperature at the center at the end of heating. On the other hand, at the time of cooling, the temperature at both ends is high, so that both ends are cooled from a state where the temperature at both ends is low and the both ends do not start to elongate as in the conventional case, and can be uniformly cooled. Therefore, when considered throughout the repetition of heating and cooling, an apparently uniform force is applied to the effective winding portion, and the occurrence of distortion due to force concentration in a part (particularly, both end portions) of the effective winding portion is suppressed. Thus, the durability of the coil spring is improved.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional side view of a refrigerator of the present invention.

FIG. 2 is an enlarged cross-sectional view showing a damper device and a surrounding structure in a state where the damper device of the present invention is arranged at an inlet portion of a cold air duct in a refrigerator.

FIG. 3 is an exploded perspective view of the damper device.

FIG. 4 shows a ternary alloy (Ni, Ti, Cu) used in the present invention.
FIG. 4 is a stress-temperature characteristic diagram of the shape memory alloy coil spring of FIG.

FIG. 5 is a diagram showing a case where an austenite shape is stored by providing a gap at one turn at both ends of an effective winding portion of the shape memory alloy coil spring of the present invention and making other portions adhere to each other.

FIG. 6 is a view when the winding diameter of the effective winding portion of the shape memory alloy coil spring of the present invention is changed.

FIG. 7 is a diagram showing a case where the Kanthal heater of the present invention is wound densely and densely.

FIG. 8 is a view showing a case where the winding diameter of the Kanthal heater of the present invention is changed.

FIG. 9 is a diagram showing a state in which the dense and densely wound cantal heater of the present invention is wound around a shape memory alloy coil spring having a different winding diameter.

FIG. 10 shows a state in which the sparsely wound cantal heater of the present invention is wound around a shape memory alloy coil spring having a different effective shape and a different memory diameter and a winding diameter and attached to a fixing member, and both ends of the heater are connected to terminals. It is a perspective view of.

FIG. 11 is a conventional shape memory alloy damper device (part 1).
3 is a diagram corresponding to FIG.

FIG. 12 shows a conventional shape memory alloy damper device (part 2).
3 is a diagram corresponding to FIG.

FIG. 13 is a stress-temperature characteristic diagram of a conventional shape memory coil spring of a binary alloy (Ti, Ni).

FIG. 14 is a perspective view showing a state in which a conventional Kanthal heater having the same interval and the same diameter is wound around a shape memory alloy coil spring, attached to a fixing member, and both ends of the heater are connected to terminals.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Refrigerator 24 Distribution cool air duct (Cool air duct) 25 Damper device 41 Opening 42 Case 43 Opening / closing plate 44 Bias spring 45 Heater 46 Shape memory alloy coil spring 46B Effective winding part 46A Invalid winding part 46Ba Both ends of effective winding part 46Bb Effective winding part Central part of heater 46B Both ends of heater 46C Central part of heater S Controller

Claims (2)

(57) [Claims] 1. A cold air duct for guiding cool air cooled by a cooler to a storage room, and a damper device for controlling the flow of cool air into the cool air duct, the damper device having an opening communicating with the cool air duct. An austenite phase transition in which a case, an opening / closing plate pivotally supported by the case to open and close the opening, a bias spring biasing the opening / closing plate in the opening direction, and an insulated heating heater are wound around the case; In a refrigerator comprising a shape memory alloy coil spring that recovers its original shape when heated to the end temperature or higher and closes the opening / closing plate against the biasing force of the bias spring, the heater has a central portion that is spaced from each other. And wound in close contact with each other as they approach portions corresponding to both ends of the shape memory alloy coil spring. The refrigerator. 2. A cool air duct for guiding cool air cooled by a cooler to a storage room, and a damper device for controlling the flow of cool air into the cool air duct, the damper device having an opening communicating with the cool air duct. An austenite phase transition in which a case, an opening / closing plate pivotally supported by the case to open and close the opening, a bias spring biasing the opening / closing plate in the opening direction, and an insulated heating heater are wound around the case; In a refrigerator comprising a shape memory alloy coil spring that recovers its original shape when heated to the end temperature or more and closes the opening and closing plate against the urging force of the bias spring, the winding diameter of the heater is The central portion corresponding to the central portion of the memory alloy coil spring is sufficiently larger than the diameter of the shape memory alloy coil spring and close to both end portions corresponding to both end portions of the shape memory alloy coil spring. Refrigerator, characterized in that it substantially is as large as Ku in accordance with the diameter of the shape memory alloy coil spring.