JP2007183126A - Method and device for evaluating thermal fatigue - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and device optimum for evaluating thermal fatigue due to a thermal stress and creep deformation caused by an atmospheric temperature in a sample exposed thereto and a difference between thermal expansion coefficients in the sample. <P>SOLUTION: The device 1 has a temperature regulation part 3, and regulates the atmospheric temperature in the sample W exposed thereto and a temperature of the sample itself, i.e. testing environment temperatures, by feeding air temperature-regulated in the temperature regulation part 3 into a testing chamber 2. The device 1 sets a temperature change rate when changing the testing environment temperature between a low-temperature set temperature and a high-temperature set temperature, and changes the testing environment temperature as set. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a thermal fatigue evaluation method and a thermal fatigue evaluation apparatus, and in particular, a thermal fatigue evaluation method optimal for evaluation of thermal fatigue due to thermal stress and creep deformation caused by a difference in thermal expansion coefficient between samples, and An object of the present invention is to provide a thermal fatigue evaluation apparatus that can suitably perform this test method.

  In recent years, with the downsizing and high functionality of electronic parts and electronic devices, the configuration has become complicated. Here, electronic components and electronic devices are often composites in which a plurality of constituent materials are joined with a joining material such as a brazing material such as solder or an adhesive. For this reason, when temperature stress is repeatedly applied due to changes in the use environment of the equipment or repeated operation / stopping, the joining material such as solder is repeatedly displaced due to the difference in linear expansion coefficient, causing deformation or fracture, so-called creep deformation occurs. there is a possibility. For this reason, a reliability evaluation test (cooling cycle test) against temperature stress is often performed in order to manufacture and develop equipment and components used for the influence of temperature stress.

Conventionally, as a method for evaluating reliability against temperature stress, a method for forcibly applying mechanical strain to a sample as disclosed in the following Patent Document 1 or disclosed in the following Patent Document 2 is disclosed. As described above, there is provided a method of exposing a sample to a high temperature atmosphere or a low temperature atmosphere to impart thermal strain to the sample.
Japanese Patent No. 2679262 Japanese Patent No. 2835780

  In the test method disclosed in Patent Document 1 above, a constant strain can be repeatedly applied to the sample, but the strain applied to the sample by this test method is a mechanical strain. There was a problem that the effect of strain could not be reproduced. Further, when the cooling cycle test method disclosed in Patent Document 2 is adopted, the ambient temperature at which the sample is exposed when the atmosphere to which the sample is exposed is changed from high temperature to low temperature or from low temperature to high temperature. Deformation or fracture of the bonding material due to thermal stress and creep deformation (hereinafter referred to as creep deformation if necessary) due to the difference in the thermal expansion coefficient of the specimens cannot be adjusted. There was a problem that it was not possible to faithfully reproduce the situation.

  Further, if the rate of change in the ambient temperature to which the sample is exposed is non-uniform for each test, the correlation between the strain rate and the strength of the sample will be different each time the test is performed. Therefore, when the conventional technology is used to perform the thermal cycle test, there is a problem that even if the test is performed a plurality of times, the data for each test cannot be compared or the accuracy of the comparison result is deteriorated.

  Accordingly, an object of the present invention is to provide a thermal fatigue evaluation method and a thermal fatigue evaluation apparatus that are optimal for evaluation of thermal fatigue due to thermal stress and creep deformation caused by differences in thermal expansion coefficients.

  Accordingly, the invention according to claim 1 provided to solve the above-described problem is a method for evaluating thermal fatigue due to thermal stress and creep deformation caused by a difference in thermal expansion coefficient between samples of electrical parts or materials. By adjusting the temperature of the gas to which the sample is exposed, the ambient temperature to which the sample is exposed and / or the temperature of the sample from a set temperature lower than room temperature to a set temperature higher than room temperature is within a predetermined error range over time. The temperature of the gas exposed to the sample and the temperature of the gas to which the sample is exposed are adjusted to change the ambient temperature and / or the temperature of the sample from the set temperature higher than room temperature to a temperature lower than room temperature. Thermal fatigue evaluation characterized by performing a temperature cycle operation including a temperature lowering operation that changes in proportion to time within a predetermined error range up to a set temperature at a predetermined cycle It is the law.

  As in the thermal fatigue evaluation method of the present invention, the temperature of the atmosphere to which the sample is exposed and / or the temperature of the sample can be changed so as to be proportional to the time within a predetermined error range in the temperature raising operation and the temperature lowering operation. For example, it is possible to faithfully reproduce the state in which the sample undergoes creep deformation or the like.

  Here, in the thermal fatigue evaluation method according to claim 1, the temperature cycle operation is a high temperature that maintains the ambient temperature to which the sample is exposed and / or the temperature of the sample at a set temperature higher than room temperature after the temperature raising operation. It may include a maintenance operation and a low temperature maintenance operation for maintaining the ambient temperature to which the sample is exposed and / or the temperature of the sample at a set temperature lower than room temperature after the temperature lowering operation (claim 2).

  That is, the thermal fatigue evaluation method according to claim 1 may be configured to repeatedly perform a temperature cycle operation including four operations of a temperature rising operation, a high temperature maintaining operation, a temperature decreasing operation, and a low temperature maintaining operation at a predetermined cycle. Good. More specifically, the thermal fatigue evaluation method of the present invention includes a series of temperature rise, high temperature maintenance, temperature fall, and low temperature maintenance of the ambient temperature to which the sample is exposed and the temperature of the sample (hereinafter referred to as test environment temperature as necessary). The cycle may be repeated a plurality of times. According to such a configuration, it is possible to more faithfully reproduce the state in which the sample undergoes creep deformation or the like.

  Here, when the thermal fatigue evaluation method according to claim 1 or 2 is performed, a set temperature lower than room temperature is set in a range of -70 ° C to 0 ° C, and a set temperature higher than room temperature is set to 60 ° C. The temperature is set in a range of ˜180 ° C., and the ambient temperature to which the sample is exposed during the temperature raising operation and the temperature lowering operation or the temperature of the sample is set to be proportional in the range of 1 ° C. to 30 ° C. per minute and changed It is desirable (Claim 3).

  If the temperature cycle test is performed under such conditions, the state in which the specimen undergoes creep deformation or the like can be reproduced more faithfully.

  In carrying out the thermal fatigue evaluation method according to claim 1 or 2, the ambient temperature to which the sample is exposed during the temperature raising operation and the temperature lowering operation, or the temperature of the sample is 5 ° C to 20 ° C per minute. If it is set so as to be proportional within the range, and it is changed, the period required for the temperature cycle test can be minimized while ensuring the accuracy of the temperature cycle test.

  Further, when the thermal fatigue evaluation method according to any one of claims 1 to 3 is performed, the error range of the ambient temperature and / or the sample temperature to which the sample is exposed during the temperature raising operation and the temperature lowering operation is + 5 ° C. It is desirable that the temperature is -5C.

  Under such conditions, it is possible to faithfully reproduce the state in which the sample undergoes creep deformation and the like, and it is possible to improve the test accuracy of the temperature cycle test.

  Here, when the present inventors conducted a temperature cycle test under various conditions, the rate of change in the test environment temperature when performing the temperature rising operation and the change in the test environment temperature when performing the temperature lowering operation It was found that the creep deformation and other aspects of the sample can be reproduced more faithfully by adjusting the ratio of the sample to be substantially the same.

  Therefore, the invention according to claim 5 provided on the basis of such knowledge provides the ratio of the temperature change of the ambient temperature to which the sample is exposed during the temperature raising operation and the temperature lowering operation, or the ratio of the temperature change of the sample. The thermal fatigue evaluation method according to any one of claims 1 to 4, wherein the temperature fatigue operation is substantially the same when the temperature raising operation is performed and when the temperature lowering operation is performed.

  If the temperature cycle test is performed under such conditions, a temperature stress can be applied to the sample in a state suitable for reproduction of creep deformation and the like, and a temperature cycle test with excellent reliability can be performed.

  In the invention according to claim 6, the ambient temperature and / or the temperature of the sample to which the sample is exposed are adjusted by arranging the sample in a predetermined test chamber and supplying the temperature-controlled gas into the test chamber. The thermal fatigue evaluation method according to any one of claims 1 to 5, wherein the wind speed in the vicinity of the sample is adjusted to be at least 2 m / second or more.

  In the conventional thermal cycle test, the wind speed of the gas introduced into the test chamber in which the sample is arranged is 1 m / second or less, whereas in the thermal fatigue evaluation method of the present invention, the wind speed in the vicinity of the sample is at least 2 m / second. Gas is supplied so that it may become 2 seconds or more. Therefore, according to the thermal fatigue evaluation method of the present invention, the heat exchange rate of the sample during the test is improved, and the ambient temperature to which the sample is exposed and the temperature of the sample itself are quickly and within a range suitable for reproduction of creep deformation and the like. It can be changed accurately.

  In addition, according to the thermal fatigue evaluation method of the present invention, the rate of change in the ambient temperature to which the sample is exposed and the temperature of the sample itself can be adjusted with high accuracy, so the correlation between the strain rate and the strength of the sample can be accurately grasped. be able to. Moreover, if a test is implemented by the thermal fatigue evaluation method of this invention, the data which show a test result can be compared accurately.

Here, the thermal fatigue evaluation method according to each of the above inventions can be implemented by a thermal fatigue evaluation apparatus having the following configuration. More specifically, the temperature control means includes a test chamber capable of accommodating the sample, temperature control means for adjusting the temperature of the gas supplied into the test chamber, and air blowing means capable of supplying gas to the test chamber. By introducing the temperature-adjusted gas into the test chamber, the ambient temperature in the test chamber in which the sample is accommodated and / or the temperature of the sample is set from a set temperature higher than room temperature to a set temperature lower than room temperature, or room temperature. A thermal fatigue evaluation apparatus capable of switching from a lower set temperature to a set temperature higher than room temperature, wherein the temperature control means is a cooling means capable of cooling the gas supplied into the test chamber, and heating the gas A cooling system for gas cooling that includes a refrigerant flow path through which the refrigerant flows and a cooler, and that can cool the gas supplied to the test chamber by the cooler. It is equipped The cooling system for cooling the gas has a bypass channel that can flow the refrigerant flowing through the refrigerant channel so as to bypass the cooler, and adjusts the amount of the refrigerant that bypasses the bypass channel. Thus, the amount of refrigerant supplied to the cooler can be adjusted. As a guide, when the test chamber is assumed to be close to a cube, the volume of the test chamber is 1 liter per minute. The thermal fatigue evaluation method described above can be carried out by a thermal fatigue evaluation apparatus characterized in that a gas of 2 m ³ or more is supplied to the test chamber.

  In the thermal fatigue evaluation apparatus having the above-described configuration, the amount of refrigerant supplied to the cooler is adjusted by adjusting the amount of refrigerant that bypasses the bypass channel provided in the refrigerant channel constituting the cooling system for gas cooling. The configuration is adjustable. Therefore, in the thermal fatigue evaluation apparatus described above, the cooling capacity of the cooling means can be accurately adjusted by adjusting the amount of refrigerant that bypasses the bypass flow path side in the cooling system for gas cooling. Therefore, the thermal fatigue evaluation apparatus described above can adjust the rate of temperature change accurately when changing the temperature of the test chamber or sample by adjusting the cooling capacity, and creep deformation of the ambient temperature to which the sample is exposed. Can be adjusted to a state suitable for reproduction.

In the thermal fatigue evaluation apparatus having the above-described configuration, 0.2 m ³ or more of gas per minute is supplied to the 1 liter capacity of the test chamber close to a cube by the blowing means. Therefore, in the above-described thermal fatigue evaluation apparatus, the ambient temperature to which the sample is exposed and the temperature of the sample itself can be quickly and accurately changed within a range suitable for reproduction of creep deformation. Therefore, according to the thermal fatigue evaluation apparatus described above, a temperature cycle test (thermal fatigue evaluation test) against temperature stress can be performed quickly and accurately.

  In addition, the above-described thermal fatigue evaluation device can accurately adjust the rate of change in the ambient temperature to which the sample is exposed and the temperature of the sample itself, so that the correlation between the strain rate and the strength of the sample can be accurately grasped. . Moreover, if a test is implemented by the above-described thermal fatigue evaluation apparatus, data indicating the test results can be compared with high accuracy.

  The invention described in claim 7 has a test chamber capable of accommodating a sample, temperature control means for adjusting the temperature of the gas supplied into the test chamber, and air blowing means capable of supplying gas to the test chamber. , By introducing a gas whose temperature is adjusted in the temperature control means into the test chamber, the ambient temperature in the test chamber in which the sample is accommodated and / or the temperature of the sample is set from a set temperature higher than room temperature to a set temperature lower than room temperature. Or a thermal fatigue evaluation apparatus capable of switching from a set temperature lower than room temperature to a set temperature higher than room temperature, wherein the ambient temperature in the test chamber and / or the temperature of the sample is within a range of −70 ° C. to 180 ° C. It can be adjusted, and the temperature rise operation that switches the ambient temperature and / or sample temperature from the set temperature lower than room temperature to the set temperature higher than room temperature, and the ambient temperature and / or sample temperature in the test chamber A high temperature maintaining operation for maintaining a higher set temperature, a temperature lowering operation for switching the atmosphere temperature and / or the temperature of the sample from a set temperature higher than room temperature to a set temperature lower than room temperature, And / or a temperature cycle operation including a low temperature maintaining operation for maintaining the temperature of the sample at a set temperature lower than room temperature, and the ambient temperature in the test chamber and / or the rate of the temperature change of the sample can be changed from 1 ° C./min. It can be set to be proportional within a range of 30 ° C., and can be changed within a predetermined error range. The execution time of the high temperature maintenance operation and the low temperature maintenance operation can be set, and the number of repetitions of the temperature cycle operation is 1. It can be set more than once, and the ambient temperature to which the sample is exposed during the temperature raising operation and the temperature lowering operation, or the rate of change of the sample temperature in the range of 1 ° C to 30 ° C per minute A thermal fatigue evaluation unit which is a constant possible.

  In the thermal fatigue evaluation apparatus of the present invention, in addition to the duration of the high temperature maintenance operation and the low temperature maintenance operation and the number of repetitions of the temperature cycle operation, the ambient temperature at which the sample is taken and the temperature of the sample during the temperature rise operation and the temperature fall operation The rate of change can be adjusted in a range suitable for reproduction of creep deformation or the like (range of 1 ° C. to 30 ° C. per minute). Therefore, according to the configuration described above, it is possible to provide a thermal fatigue evaluation apparatus capable of adjusting the atmospheric temperature in the test chamber and the temperature change of the sample to an accurate state to reproduce the state of creep deformation of the sample.

  As described above, in the thermal fatigue evaluation apparatus of the present invention, the ambient temperature to which the sample is exposed and the rate of change in the temperature of the sample itself can be adjusted. Therefore, according to the thermal fatigue evaluation apparatus of the present invention, the correlation between the strain rate of the sample and the strength of the sample can be accurately grasped. Furthermore, according to the thermal fatigue evaluation apparatus of the present invention, data indicating test results can be compared with high accuracy.

  The invention according to claim 8 employs, as the temperature control means, a cooling means capable of cooling the gas supplied into the test chamber and a heating means capable of heating the gas. The cooling means includes a refrigerant flow path through which the refrigerant flows and a cooler, and includes a cooling system for gas cooling that can cool the gas supplied to the test chamber by the cooler. The cooling system has a bypass flow path that can flow the refrigerant flowing through the refrigerant flow path so as to bypass the cooler, and adjusts the amount of the refrigerant that bypasses the bypass flow path to the cooler. The amount of refrigerant supplied can be adjusted, and the amount of refrigerant bypassing to the bypass channel side in the cooling system for gas cooling is adjusted according to changes in the ambient temperature in the test chamber and / or changes in the temperature of the sample. Cooling capacity of the cooling means The heating means is operated so as to supplement an amount of heat excessively cooled with respect to a set value of the ambient temperature in the test chamber and / or a set value of the temperature of the sample while adjusting. 7. The thermal fatigue evaluation apparatus according to 7.

  In the thermal fatigue evaluation apparatus of the present invention, the cooling means and the heating means operate in a complementary manner, and the atmospheric temperature change in the test chamber and the sample temperature change can be accurately controlled. Therefore, according to the thermal fatigue evaluation apparatus of the present invention, the atmospheric temperature in the test chamber and the temperature change of the sample can be adjusted to a state suitable for reproducing the creep deformation of the sample.

  According to the ninth aspect of the present invention, the high temperature maintaining operation is started after a predetermined delay time from when the set temperature higher than the room temperature is reached by the temperature raising operation, and the low temperature maintaining operation is performed at a temperature lower than the room temperature by the temperature lowering operation. 9. The thermal fatigue evaluation apparatus according to claim 8, wherein the thermal fatigue evaluation apparatus is started after a predetermined delay time has elapsed from the time when the set temperature is reached.

  In the thermal fatigue evaluation apparatus of the present invention, since the high temperature maintenance operation and the low temperature maintenance operation are started after the atmosphere temperature in the test chamber and the temperature of the sample are stabilized, the sample is placed under the environment of the high temperature setting temperature or the low temperature setting temperature. It is possible to minimize variations in the exposure time and to accurately reproduce the creep deformation of the sample.

  The invention according to claim 10 is provided with a cooling means capable of cooling the gas supplied into the test chamber and a heating means capable of heating the gas as temperature control means, The cooling means includes a refrigerant flow path through which the refrigerant flows and a cooler, and includes a cooling system for gas cooling that can cool the gas supplied to the test chamber by the cooler. A cooling system is provided in the refrigerant flow path, the first and second bypass flow paths capable of flowing the refrigerant flowing through the refrigerant flow path so as to bypass the cooler, and the cooler A variable flow rate expansion valve capable of adjusting the amount of refrigerant flowing into the first flow path, a first bypass valve capable of opening and closing the first bypass flow path, and a refrigerant that is provided in the first bypass flow path and flows through a cooling system Thermal expansion that opens and closes or changes in opening according to the temperature of A valve, a second bypass valve capable of opening and closing the second bypass flow path, and a capacity expansion valve provided in the second bypass flow path and adjusting a capacity in accordance with a change in cooling load. The amount of refrigerant supplied to the cooler can be adjusted by adjusting the variable flow rate expansion valve, and the ambient temperature and / or sample temperature in the test chamber can be adjusted from a set temperature lower than room temperature to higher than room temperature. Temperature increase operation to switch to the set temperature of the test chamber, high temperature maintenance operation to maintain the ambient temperature of the test chamber and / or the temperature of the sample at a set temperature higher than room temperature, and the ambient temperature of the test chamber and / or the temperature of the sample from the room temperature A temperature cycle including a temperature lowering operation for switching from a high temperature setting temperature to a temperature setting lower than room temperature, and a low temperature maintenance operation for maintaining the ambient temperature in the test room and / or the sample temperature at a temperature lower than room temperature. The operation can be performed, and during the temperature raising operation, the first and second bypass valves are opened, and the opening of the variable flow rate expansion valve is adjusted to 10% or less. The output of the heating means is adjusted with the first and second bypass valves opened during the high temperature maintenance operation and the opening of the variable flow rate expansion valve adjusted to 10% or less. The temperature is adjusted within a range of 30 to 50%. During the temperature lowering operation, the first and second bypass valves are closed, and the opening of the variable flow rate expansion valve is adjusted within a range of 50 to 100% and heating is performed. The output of the means is adjusted within the range of 0 to 20%, and during the low temperature maintenance operation, the first bypass valve is closed, the second bypass valve is opened, and the flow variable expansion valve is opened. The degree is adjusted within the range of 30-50%, and the output of the heating means is within the range of 20-30% The thermal fatigue evaluation device according to any one of claims 7 to 9, wherein the thermal fatigue evaluation device is adjusted within the range.

  According to such a configuration, the atmosphere temperature in the test chamber and the temperature of the sample can be accurately and accurately adjusted in a series of temperature cycles. Therefore, according to the present invention, the atmosphere temperature in the test chamber and the temperature of the sample can be adjusted to an appropriate state to reproduce the state of creep deformation of the sample, and a highly accurate thermal fatigue evaluation test can be performed. .

  The invention according to claim 11 is capable of setting the set value of the test chamber atmosphere temperature, or the rate of temperature change at the time of switching the set value of the sample temperature, and the set value of the rate of temperature change, The amount of the refrigerant that bypasses to the bypass channel side is adjusted based on the set value of the ambient temperature of the test chamber and / or the set value of the temperature of the sample. It is a thermal fatigue evaluation device.

  According to such a configuration, it is possible to provide a thermal fatigue evaluation apparatus that can adjust the atmospheric temperature in the test chamber to which the sample is exposed and the temperature of the sample itself to a state suitable for reproduction of creep deformation and the like, and can perform the temperature cycle test with high accuracy. .

  Moreover, similarly to the thermal fatigue evaluation apparatus according to the seventh to tenth aspects, the thermal fatigue evaluation test can be suitably performed even with the following configuration. That is, the thermal fatigue evaluation apparatus of the present invention comprises a test chamber capable of accommodating a sample, a temperature adjusting means for adjusting the temperature of the gas supplied into the test chamber, and a blower means capable of supplying gas to the test chamber. And introducing the gas whose temperature is adjusted in the temperature control means into the test chamber, so that the ambient temperature in the test chamber in which the sample is accommodated and / or the temperature of the sample is lower than the set temperature higher than room temperature. A thermal fatigue evaluation apparatus capable of switching from a set temperature or a set temperature lower than room temperature to a set temperature higher than room temperature, wherein the temperature adjusting means can cool the gas supplied into the test chamber And a heating means capable of heating the gas, wherein the cooling means includes a refrigerant flow path through which the refrigerant flows and a cooler, and a gas capable of cooling the gas supplied to the test chamber by the cooler. Cooling for cooling The cooling system for cooling the gas has one or a plurality of bypass passages through which the refrigerant flowing through the refrigerant passages can flow so as to bypass the cooler, The amount of refrigerant supplied to the cooler can be adjusted by adjusting the amount of refrigerant bypassing to the bypass channel side, and switching between the set value of the test chamber ambient temperature or the sample temperature The ratio of the temperature change at the time can be set, and the amount of refrigerant bypassing to the bypass channel side is adjusted based on the ratio of the temperature change and the ambient temperature of the test chamber and / or the temperature of the sample. It may be.

  According to such a configuration, in the refrigerant flow path constituting the cooling system provided for cooling the gas supplied to the test chamber, by adjusting the amount of the refrigerant that bypasses the cooler and flows to the bypass flow path side, The gas introduced into the test chamber can be accurately cooled. Therefore, if the thermal fatigue evaluation apparatus is configured as described above, the ambient temperature of the test chamber and the temperature of the sample during the temperature cycle test can be stabilized.

  Moreover, the thermal fatigue evaluation apparatus having the above-described configuration is configured to be able to set the rate of change of these temperatures when changing the ambient temperature of the test chamber or the temperature condition of the sample itself, Based on the ratio, the actual ambient temperature of the test chamber, and the temperature of the sample, the amount of refrigerant bypassing to the bypass channel side is adjusted. Therefore, according to the configuration described above, the thermal fatigue evaluation apparatus capable of adjusting the atmospheric temperature to which the sample is exposed and the temperature of the sample itself to a state suitable for reproduction of creep deformation and the like and capable of performing a reliable temperature cycle test. Can be provided.

  In addition, if the configuration as described above is adopted, the rate of change in the ambient temperature to which the sample is exposed and the temperature of the sample itself can be accurately adjusted, so the correlation between strain rate and sample strength can be accurately grasped. Can do. Moreover, if the above-described configuration is adopted, data indicating test results can be compared with high accuracy.

  Here, the thermal fatigue evaluation apparatus according to any of claims 8 to 11 may be capable of supplying gas so that the wind speed in the vicinity of the sample is at least 2 m / second or more. 12).

  According to such a configuration, the ambient temperature to which the sample is exposed and the temperature of the sample itself can be quickly changed within a range suitable for reproduction of creep deformation and the like, and a temperature cycle test against temperature stress can be quickly performed.

  Here, in the thermal fatigue evaluation apparatus according to any one of claims 7 to 12, the cooling means includes a plurality of cooling systems including a first cooling system and a second cooling system, and the first The cooling system is a cooling system for gas cooling, a refrigerant flow path through which the refrigerant flows, a cooler capable of cooling the gas supplied to the test chamber, and the refrigerant flowing through the refrigerant flow path bypassing the cooler. A bypass channel that can be flowed in such a manner that the amount of refrigerant supplied to the cooler can be adjusted by adjusting the amount of refrigerant that bypasses the bypass channel. The two cooling systems may include a refrigerant system capable of exchanging heat with the refrigerant flow path constituting the first cooling system.

  The cooling means employed in the configuration described above includes a plurality of cooling systems, a refrigerant flow path of the first cooling system including a gas cooling cooler, and a refrigerant flow path constituting the second cooling system. And a so-called multi-cooling (refrigeration) system that can exchange heat with each other. Therefore, if the above-described configuration is adopted, the gas can be cooled to an extremely low temperature.

  Here, the thermal fatigue evaluation apparatus according to any one of claims 7 to 12 is configured such that the rate of change in temperature at the time of switching the set value of the ambient temperature of the test chamber or the set value of the temperature of the sample is 1 per minute. It may be adjustable within the range of from 30 ° C to 30 ° C.

  According to such a configuration, the ambient temperature in the test chamber in which the sample is arranged and the temperature of the sample itself can be changed quickly within a range suitable for reproduction of creep deformation, etc., and the temperature cycle test against temperature stress is quickly performed. be able to.

  Here, when the present inventors conducted a temperature cycle test using the thermal fatigue evaluation apparatus of the present invention described above, the ambient temperature of the test chamber in which the sample is accommodated and / or the temperature of the sample is lower than room temperature. The rate of temperature change when performing a temperature raising operation to switch from a set temperature to a set temperature higher than room temperature, and the ambient temperature and / or sample temperature of the test chamber in which the sample is stored from the set temperature higher than room temperature. It was found that the state of creep deformation and the like of the sample can be faithfully reproduced by adjusting so that the rate of temperature change during the temperature lowering operation for switching to a set temperature lower than room temperature is substantially the same.

  Accordingly, the invention according to claim 13 provided on the basis of such knowledge is that the ambient temperature of the test chamber in which the sample is accommodated and / or the temperature of the sample is set from a set temperature lower than room temperature to a set temperature higher than room temperature. Temperature increase operation to switch to, atmosphere temperature of the test chamber in which the sample is accommodated and / or high temperature maintenance operation to maintain the temperature of the sample at a set temperature higher than room temperature, and atmosphere temperature of the test chamber in which the sample is accommodated And / or a temperature lowering operation for switching the temperature of the sample from a set temperature higher than room temperature to a set temperature lower than room temperature, and the ambient temperature of the test chamber in which the sample is accommodated and / or the temperature of the sample lower than the room temperature. It is possible to perform a temperature cycle test in which the low temperature maintenance operation is maintained in order, and the rate of temperature change is substantially the same when the temperature increase operation is performed and when the temperature decrease operation is performed. A thermal fatigue evaluation apparatus according to any one of claims 7 to 12, characterized in that.

  According to this configuration, temperature stress can be applied to the sample in a state suitable for reproduction of creep deformation and the like, and the temperature cycle test of the sample can be performed with high accuracy.

  According to the fourteenth aspect of the present invention, an error in the ambient temperature of the test chamber and / or the temperature of the sample at the time of performing the temperature raising operation and the temperature lowering operation, the set value of the test chamber ambient temperature, and / or the sample It is adjustable within the range of +5 degreeC--5 degreeC with respect to the set value of temperature of this, The thermal fatigue evaluation apparatus in any one of Claims 7-13 characterized by the above-mentioned.

  According to the thermal fatigue evaluation apparatus of the present invention, it is possible to maintain the atmosphere temperature in the test chamber and the temperature of the sample within the optimum error range for the thermal fatigue evaluation, so that the state in which the sample undergoes creep deformation or the like can be accurately reproduced. be able to.

  Here, the thermal fatigue evaluation apparatus according to any one of claims 7 to 14 is configured such that the rate of change in the ambient temperature of the test chamber or the temperature of the sample when the temperature raising operation and the temperature lowering operation are performed is 1 per minute. It can be set in the range of -30 ° C, the low temperature can be set in the range of -70 ° C to 0 ° C, and the high temperature can be set in the range of 60 ° C to 180 ° C. desirable.

  According to this configuration, it is possible to apply temperature stress to the sample in a state suitable for reproducing creep deformation and the like, and it is possible to further improve the accuracy of the temperature cycle test of the sample.

  The thermal fatigue evaluation apparatus according to any one of claims 7 to 14 is configured such that the rate of change in the ambient temperature of the test chamber or the temperature of the sample during the temperature raising operation and the temperature lowering operation is 5 ° C per minute. It can also be set as the structure which can be set in the range of -20 degreeC. With such a configuration, it is possible to minimize the period required for the thermal fatigue evaluation test while further improving the accuracy of the temperature cycle test.

  Here, in the thermal fatigue evaluation apparatus according to any one of claims 7 to 14, the heating capacity and the cooling capacity required for the heating means and the cooling means are calculated and derived, and based on this, the heating means and the cooling capacity are calculated. When the configuration is such that the output value of the means is adjusted, it is desirable to calculate the heating capacity and the cooling capacity as frequently as possible.

  Therefore, the invention according to claim 15 provided on the basis of such knowledge detects the atmospheric temperature of the test chamber or the temperature of the sample, and the heating capacity required for the heating means and the cooling means based on the temperature. The cooling capacity is calculated and derived, and the output values of the heating means and the cooling means are adjusted based on the calculation results, and the calculation is performed in a cycle of 1 second or less. It is a thermal fatigue evaluation apparatus in any one of 7-14.

  According to such a configuration, the output values of the heating unit and the cooling unit can be precisely adjusted, and the atmosphere temperature of the test chamber and the temperature of the sample can be adjusted with high accuracy. Therefore, according to the present invention, it is possible to provide a thermal fatigue evaluation apparatus that can apply temperature stress to a sample in a state suitable for reproduction of creep deformation and the like and can perform a temperature cycle test of the sample with high accuracy.

  ADVANTAGE OF THE INVENTION According to this invention, the thermal fatigue evaluation method and thermal fatigue evaluation apparatus which can adjust the atmospheric temperature to which a sample is exposed, and the temperature of the sample itself to the state suitable for reproduction, such as creep deformation, can be provided.

  Then, the thermal fatigue evaluation apparatus and thermal fatigue evaluation method concerning one Embodiment of this invention are demonstrated in detail, referring drawings. In FIG. 1, 1 is a thermal fatigue evaluation apparatus of this embodiment. The thermal fatigue evaluation apparatus 1 includes a test chamber 2 that accommodates a sample W to be tested, a temperature control unit 3 (temperature control means) for adjusting the temperature of air fed into the test chamber 2, and a temperature control unit And control means 10 for controlling the operation of No. 3.

  The test chamber 2 has a space that can accommodate the sample W for performing the thermal fatigue evaluation test. More specifically, the test chamber 2 has a capacity of 150 liters. An atmosphere temperature sensor 25 and a sample temperature sensor 26 are provided inside the test chamber 2. The ambient temperature sensor 25 can detect the ambient temperature in the test chamber 2. The sample temperature sensor 26 is configured to be able to detect the temperature of the sample W by being attached to the sample W arranged in the test chamber 2.

  The temperature adjustment unit 3 includes a cooling unit 5 (cooling unit), a heating unit 6 (heating unit), and a blower unit 7 (blower unit). The thermal fatigue evaluation device 1 controls the operations of the cooling unit 5, the heating unit 6, and the air blowing unit 7 that constitute the temperature control unit 3 according to the test conditions set via the setting unit 20, and enters the test chamber 2. Heated or cooled air is sent in to adjust the atmospheric temperature in the test chamber 2 or the temperature of the sample W installed in the test chamber 2 to a high temperature state or a low temperature state.

  As shown in FIG. 2, the cooling unit 5 is configured to employ a cooling circuit 30 of a so-called multi-source cooling (refrigeration) system (in this embodiment, a dual cooling system). The cooling unit 5 is configured by combining a low temperature side cooling system 31 and a high temperature side cooling system 32, and both are thermally connected via a cascade capacitor 35.

  The low temperature side cooling system 31 has a low temperature side refrigerant flow path 37 through which the refrigerant can circulate, and a cascade capacitor 35 and a low temperature side cooler 36 are provided in the middle. The high temperature side cooling system 32 has a high temperature side refrigerant flow path 65 through which the refrigerant can circulate, and a cascade capacitor 35 and a high temperature side condenser 38 are arranged in the middle. That is, in the cooling unit 5, the cascade condenser 35 is configured such that the low temperature side refrigerant flow path 37 and the high temperature side refrigerant flow path 65 are connected. Accordingly, the cascade capacitor 35 functions as a condenser of the low temperature side cooling system 31 and also functions as a cooler of the high temperature side cooling system 32, and thermally connects the low temperature side cooling system 31 and the high temperature side cooling system 32. ing. In other words, the cooling circuit 30 is configured such that heat can be exchanged between the low temperature side cooling system 31 and the high temperature side cooling system 32 in the cascade condenser 35.

  In the middle of the low temperature side refrigerant flow path 37 constituting the low temperature side cooling system 31, a low temperature side compressor 41, an oil separator 42, an accumulator 43, a heat exchanger 45, an expansion valve 46 (variable flow rate expansion valve), an electromagnetic valve 47. It is set as the structure provided. The low temperature side cooling system 31 operates through the low temperature side cooler 36 as shown by an arrow A in FIG. 2 by operating the low temperature side compressor 41 with the expansion valve 46 and the electromagnetic valve 47 open. It is possible to circulate the refrigerant.

  The expansion valve 46 is a so-called electronic expansion valve, and can be opened and closed based on a control signal transmitted from the control means 10. The expansion valve 46 (hereinafter referred to as an electronic expansion valve 46 if necessary) is disposed upstream of the low-temperature side cooler 36 in the refrigerant flow direction and downstream of the cascade condenser 35 in the refrigerant flow direction. Has been. Further, the solenoid valve 47 is also configured to be opened and closed based on a control signal transmitted from the control means 10. The electromagnetic valve 47 is arranged upstream of the electronic expansion valve 46 in the refrigerant flow direction and downstream of the cascade condenser 35 in the refrigerant flow direction.

  Three bypass flow paths 50, 51, 52 are provided in the middle of the low temperature side refrigerant flow path 37. The bypass flow paths 50, 51, 52 are all provided to bypass the low temperature side cooler 36. The bypass flow path 50 is a flow path that bypasses a position on the downstream side in the flow direction of the refrigerant flowing through the low-temperature side refrigerant flow path 37 with respect to the cooler 36 and a position between the electromagnetic valve 47 and the cascade capacitor 35. That is, the bypass flow path 50 is a flow path that flows the refrigerant so as to bypass the low-temperature side cooler 36 and returns it to the cascade condenser 35 as indicated by an arrow B in FIG.

  An expansion valve 55 and an electromagnetic valve 56 (first bypass valve) are provided in the middle of the bypass passage 50 (hereinafter referred to as the first bypass passage 50 as necessary). The expansion valve 55 is a so-called temperature type expansion valve, and can be opened and closed according to the temperature of the refrigerant. That is, the expansion valve 55 automatically opens and closes when the temperature of the refrigerant flowing downstream from the low temperature side cooler 36 is input, and the low temperature side cooling is performed in order to lower the temperature of the refrigerant flowing through the low temperature side compressor 41. It is configured such that it opens when the temperature of the refrigerant flowing downstream from the container 36 is high and closes when the temperature is low. Further, the electromagnetic valve 56 is configured to be openable and closable based on a control signal transmitted from the control means 10.

  The bypass passage 51 (hereinafter referred to as the second bypass passage 51 as needed) is provided for adjusting the output of the low-temperature side compressor 41, and is a low-temperature side refrigerant with respect to the low-temperature side cooler 36. This is a flow path that bypasses the position on the downstream side in the flow direction of the refrigerant flowing through the flow path 37 and the position between the cascade condenser 35 and the heat exchanger 45. That is, the second bypass flow path 51 is a flow path for supplying the heat exchanger 45 with the refrigerant flowing so as to bypass the low temperature side cooler 36 and the cascade condenser 35 as indicated by an arrow C in FIG.

  An expansion valve 57 and an electromagnetic valve 58 (second bypass valve) are provided in the middle of the second bypass flow path 51. The expansion valve 57 is a so-called capacity expansion valve, and is provided to control the capacity of the low temperature side compressor 41 in accordance with load fluctuations. The electromagnetic valve 58 is arranged upstream of the capacity expansion valve 57 in the refrigerant flow direction, and can be opened and closed based on a control signal transmitted from the control means 10.

  The bypass flow path 52 (hereinafter referred to as the third bypass flow path 52 as required) is provided for the security of the low temperature side cooling system 31, and has the same low temperature as the second bypass flow path 51 described above. This is a flow path that bypasses a position on the downstream side in the flow direction of the refrigerant flowing through the low temperature side refrigerant flow path 37 with respect to the side cooler 36 and a position between the cascade condenser 35 and the heat exchanger 45. An electromagnetic valve 60 is provided in the middle of the third bypass flow path 52 and can be opened and closed based on a control signal transmitted from the control means 10 as necessary.

  The high temperature side cooling system 32 includes a high temperature side condenser 38 and a high temperature side refrigerant flow path 65 through which the refrigerant can circulate, and a cascade capacitor 35 is provided in the middle of the high temperature side refrigerant flow path 65. It has a configuration. In the high temperature side cooling system 32, the cascade capacitor 35 functions as a cooler and thermally connects the low temperature side cooling system 31 and the high temperature side cooling system 32.

  In the middle of the high temperature side refrigerant flow path 65, a high temperature side compressor 66, an accumulator 68, an expansion valve 70, and an electromagnetic valve 71 are provided. The high temperature side compressor 66 and the accumulator 68 are disposed downstream of the cascade condenser 35 in the refrigerant flow direction and upstream of the high temperature side condenser 38. Further, the expansion valve 70 and the electromagnetic valve 71 are arranged at a position upstream of the cascade condenser 35 in the refrigerant flow direction and downstream of the high temperature side condenser 38. The expansion valve 70 is configured to automatically open and close when the temperature of the refrigerant flowing downstream from the cascade condenser 35 is input.

  The cooling unit 5 is configured to include the cooling circuit 30 as described above. The cooling circuit 30 operates the low temperature side compressor 41 of the low temperature side cooling system 31 and the high temperature side compressor 66 of the high temperature side cooling system 32 to circulate the refrigerant through the low temperature side refrigerant flow path 37 and the high temperature side refrigerant flow path 65. In addition, by causing heat exchange between the flow paths 37 and 65 in the cascade condenser 35, the low temperature side cooler 36 can cool the air to an extremely low temperature of about -70 ° C to -40 ° C. .

  The heating unit 6 is configured by a conventionally known heater. The heating unit 6 is configured such that the output can be appropriately adjusted based on a control signal from the control means 10.

  The ventilation part 7 is set as the structure provided with the conventionally well-known air blower. The thermal fatigue evaluation apparatus 1 can send the air whose temperature has been adjusted in the cooling unit 5 or the heating unit 6 into the test chamber 2 by operating the air blowing unit 7. The thermal fatigue evaluation apparatus 1 is configured to introduce a large amount of wind to the capacity of the test chamber 2 close to a cube in order to improve the heat exchange rate of the sample W in the test chamber 2. More specifically, the thermal fatigue evaluation apparatus 1 is configured such that the wind speed in the vicinity of the sample W is at least 2 m / second or more by operating the air blowing unit 7.

Further, the thermal fatigue evaluation apparatus 1, by operating the blower 7 with respect to 1 liter of the test chamber 2, there is a possible introduction min 0.2 m ³ or more air configuration. That is, the thermal fatigue evaluation apparatus 1 is configured to be able to introduce air of 30 m ³ or more per minute because the test chamber 2 has a capacity of 150 liters. In thermal fatigue evaluation apparatus 1 of the present embodiment, when the implementation of the temperature cycle test, in a state where the air per minute 40 m ³ (per minute 0.27 m ³ relative to 1-liter test chamber 2) is temperature adjusted It is configured to be introduced into the test chamber 2.

  As shown in FIG. 1, the control means 10 has an input unit 80, a control unit 81, a data storage unit 82, a calculation unit 83, and an output unit 85, which are in an electrically connected state. The input unit 80 is configured to be able to input detection signals from the ambient temperature sensor 25 and the sample temperature sensor 26 provided in the test chamber 2. In addition, data such as test conditions of the thermal fatigue evaluation test input via the setting means 20 provided separately is input to the input unit 80. More specifically, the thermal fatigue evaluation apparatus 1 uses the control means 10 to determine the test temperature of the thermal fatigue evaluation test, that is, the test temperature on the high temperature side and the low temperature side, the holding time held at the test temperature, and the test environment. The operation of the thermal fatigue evaluation apparatus 1 based on conditions regarding the temperature change rate (absolute value of the temperature gradient) at the time of switching, the test time (or the number of test cycles), and the detection signal of either the ambient temperature sensor 25 or the sample temperature sensor 26 It is possible to set the test conditions necessary for the thermal fatigue evaluation test, such as controlling Data such as test conditions input to the input unit 80 is stored in the data storage unit 82.

  Data such as test conditions stored in the data storage unit 82, the temperature in the test chamber 2 and the temperature of the sample W input via the input unit 80 are processed in the calculation unit 83, and the control unit 81 Is input. The control unit 81 determines control methods and parameters for the cooling unit 5, the heating unit 6, and the air blowing unit 7 based on the calculation result input from the calculation unit 83, the temperature in the test chamber 2, the temperature of the sample W, and the like. . The output unit 85 transmits a control signal to the cooling unit 5, the heating unit 6, and the blower unit 7 in accordance with the control method and parameters determined by the control unit 81, and these operations are performed within the test chamber 2 and the temperature of the sample W. Is controlled to be adjustable as set via the control means 10.

  More specifically, the thermal fatigue evaluation apparatus 1 sends the air heated or cooled in the temperature adjusting unit 3 into the test chamber 2 in accordance with the test conditions set via the setting means 20, as shown in FIG. ), The ambient temperature in the test chamber 2 and the temperature of the sample W arranged in the test chamber 2 are referred to as a high temperature and a low temperature setting temperature (hereinafter referred to as a high temperature setting temperature Sh and a low temperature setting temperature Sc as necessary). ), The temperature cycle that is changed abruptly and repeatedly is repeated, and the sample W can be subjected to thermal stress.

  The thermal fatigue evaluation apparatus 1 includes an ambient temperature control mode for controlling the operation of the temperature adjustment unit 3 based on the temperature in the test chamber 2 detected by the ambient temperature sensor 25, and a sample temperature sensor 26 attached to the sample W. The thermal fatigue evaluation test can be carried out by selecting any one of the sample temperature control modes for controlling the operation of the temperature adjustment unit 3 based on the detected temperature. In addition to the high temperature set temperature Sh and the low temperature set temperature Sc via the setting means 20, the thermal fatigue evaluation apparatus 1 holds the holding time T, the temperature change rate U (absolute value of the temperature gradient) when switching the test environment, The number of cycles N and the operation mode can be set.

  Here, in the thermal fatigue evaluation apparatus 1 of the present embodiment, the high temperature set temperature Sh can be set within a range of 60 ° C to 180 ° C. In addition, the low temperature setting temperature Sc can be set in the range of -70 ° C to 0 ° C.

  The holding time T indicates the time during which the temperature of the test chamber 2 and the temperature of the sample W are held at the high temperature set temperature Sh and the low temperature set temperature Sc in the temperature cycle, and the sample W is exposed to this environment. In the thermal fatigue evaluation apparatus 1 of the present embodiment, the holding time T is the case where the atmosphere temperature of the test chamber 2 or the temperature of the sample W (hereinafter referred to as the test environment temperature P if necessary) is held at the high temperature setting temperature Sh. And the same value when the test environment temperature P is held at the low temperature setting temperature Sc.

  The temperature change rate U is the absolute value of the temperature gradient when the test environment temperature P is lowered from the high temperature setting temperature Sh to the low temperature setting temperature Sc or when the temperature is raised from the low temperature setting temperature Sc to the high temperature setting temperature Sh. Point to. In the thermal fatigue evaluation apparatus 1, the temperature change rate U is the same when the temperature is lowered and when the temperature is raised. Moreover, in the thermal fatigue evaluation apparatus 1 of this embodiment, the temperature change rate U can be set within a range of 1 ° C. to 30 ° C. per minute.

  The cycle number N is the number of executions of the temperature cycle performed in the thermal fatigue evaluation test. More specifically, in the thermal fatigue evaluation apparatus 1, as shown in FIG. 4A, a temperature raising operation for raising the test environment temperature P to the high temperature set temperature Sh, and the test environment temperature P is held at the high temperature set temperature Sh. A temperature cycle for sequentially performing four operations including a high temperature maintaining operation that is maintained over time T, a temperature lowering operation that reduces the test environment temperature P to the low temperature setting temperature Sc, and a low temperature maintenance operation that maintains the test environment temperature P at the low temperature setting temperature Sc. It is set as the structure which repeatedly implements. Therefore, the thermal fatigue evaluation apparatus 1 is configured such that the number of executions of the temperature cycle described above can be set as the cycle number N.

  The thermal fatigue evaluation apparatus 1 can select one of the above-described ambient temperature control mode and sample temperature control mode as the operation mode. In the thermal fatigue evaluation apparatus 1, when the ambient temperature control mode is selected as the test method, the operation of the temperature adjustment unit 3 is controlled based on the detection signal (detected temperature) of the ambient temperature sensor 25, and the sample temperature control mode is set. When selected, the operation of the temperature adjustment unit 3 is controlled based on the detection signal of the sample temperature sensor 26 attached to the sample W.

  Next, the operation of the thermal fatigue evaluation apparatus 1 of the present embodiment will be described in detail with reference to the timing chart of FIG. 4 and the flowchart of FIG. As shown in FIG. 4, the thermal fatigue evaluation apparatus 1 has a predetermined number of cycles N of a temperature cycle in which the four-stage operation including the temperature raising operation, the high temperature maintaining operation, the temperature lowering operation, and the low temperature maintaining operation is one cycle. repeat.

The operation of each part will be described in more detail. As described above, the air blowing part 7 is always 40 m ³ per minute during the thermal fatigue evaluation test (about 0. air 27m ³⁾ is configured to be introduced into the test chamber 2 in a state of being temperature adjusted. On the other hand, as shown in FIG. 3, the cooling unit 5 and the heating unit 6 are based on the implementation stage of the thermal fatigue evaluation test and preset conditions such as the high temperature set temperature Sh, the low temperature set temperature Sc, and the temperature change rate U. Output is adjusted. That is, as shown in FIG. 4 and Table 1, the thermal fatigue evaluation apparatus 1 is configured to repeatedly perform the temperature cycle over the number of cycles N by adjusting the outputs of the cooling unit 5 and the heating unit 6.

  More specifically, when the temperature cycle is in the stage of the temperature raising operation, that is, in the process of raising the test environment temperature P toward the high temperature setting temperature Sh, the output of the cooling unit 5 is suppressed to the minimum. In addition, the output of the heating unit 6 is adjusted within a range of 60% to 100% of the heating capacity. That is, during the temperature raising operation, as shown in Table 1, the electromagnetic valves 47, 56, and 58 provided in the low temperature side refrigerant flow path 37 and the first and second bypass flow paths 50 and 51 are opened. The During the temperature raising operation, the opening degree of the electronic expansion valve 46 provided on the upstream side of the low temperature side cooler 36 is reduced to about 10%. Accordingly, most of the refrigerant flowing through the low temperature side refrigerant flow path 37 bypasses the low temperature side cooler 36, and the cooling capacity of the low temperature side cooler 36 is suppressed to the minimum. On the other hand, during the temperature raising operation, the test environment temperature P is within a predetermined error range (± 3.0 ° C. in this embodiment) with respect to the passage of time at the previously set temperature change rate U. The heating capacity of the heating unit 6 is adjusted so as to change proportionally (increase in temperature).

  When the test environment temperature P reaches the preset high temperature set temperature Sh as described above, the temperature cycle shifts to the implementation stage of the high temperature maintenance operation. During the high temperature maintenance operation, that is, until the predetermined holding time T elapses after the test environment temperature P reaches the high temperature set temperature Sh, the cooling unit 5 is used to maintain the test environment temperature P at the high temperature set temperature Sh. The cooling capacity of the heating unit 6 is adjusted based on the detected temperatures of the ambient temperature sensor 25 and the sample temperature sensor 26. That is, during the high temperature maintenance operation, the electromagnetic valves 47, 56, and 58 are opened as shown in Table 1, and the opening degree of the electronic expansion valve 46 is reduced to about 10%. On the other hand, the output of the heating unit 6 is adjusted between 30% and 50% in order to maintain the test environment temperature P at the high temperature setting temperature Sh.

  When a predetermined holding time T elapses from the start of the high temperature maintenance operation, the temperature cycle shifts to the temperature lowering operation execution stage. More specifically, as shown in FIG. 4 and Table 1, when the temperature lowering operation is performed, a control signal is transmitted from the control means 10 to the cooling unit 5 and the heating unit 6, and the respective outputs are adjusted. The That is, when the temperature lowering operation is performed, a control signal is transmitted from the control means 10 to the cooling unit 5, and the electromagnetic valve 58 provided in the second bypass flow path 51 is closed. Further, the electromagnetic valve 56 provided in the first bypass flow path 50 is for a while after the start of the temperature lowering operation, that is, immediately after the start of the temperature decrease of the test environment temperature P, while not requiring a large cooling capacity. Is maintained in the open state, but is then closed when the test environment temperature P decreases to some extent and a large cooling capacity is required. When the solenoid valves 56 and 58 are closed, a large amount of refrigerant circulating through the low temperature side cooling system 31 is supplied to the low temperature side cooler 36, and the cooling capacity of the cooling unit 5 is improved. .

  Further, during the temperature lowering operation, the output (cooling capacity) of the cooling unit 5 required for lowering the test environment temperature P at the previously set temperature change rate U is output from the calculation unit 83 of the control means 10. In accordance with this, the controller 81 determines the opening degree of the electronic expansion valve 46 provided in the middle of the low temperature side refrigerant flow path 37. Based on this determination, a control signal is transmitted from the output unit 85 to the cooling unit 5, and the opening degree of the electronic expansion valve 46 is adjusted. At this time, the opening degree of the electronic expansion valve 46 changes between 50% and 100%.

  Furthermore, the control means 10 transmits a control signal to the heating unit 6 even when the temperature lowering operation is being performed, and exhibits the heating capability as necessary. More specifically, in this embodiment, the output of the heating unit 6 is adjusted between 0% and 20% during the temperature lowering operation. As a result, the degree of decrease in the test environment temperature P deviates from the previously set temperature change rate U because the cooling capacity of the cooling unit 5 is excessively exhibited due to factors such as a control error of the cooling unit 5, A sudden drop is prevented. More specifically, during the temperature lowering operation, the test environment temperature P is within a predetermined error range (within the range of ± 3.0 ° C. in the present embodiment) with respect to the passage of time at the previously set temperature change rate U. ) To change proportionally (decrease in temperature).

  When the test environment temperature P reaches the low temperature setting temperature Sc by performing the temperature lowering operation, the temperature cycle shifts to the execution stage of the low temperature maintenance operation. When the low temperature maintaining operation is started, the test environment temperature P is held at the low temperature setting temperature Sc over the holding time T. More specifically, as shown in FIG. 4 and Table 1, the electromagnetic valve 47 is maintained in the open state and the electromagnetic valve 56 of the first bypass channel 50 is maintained in the closed state during the low temperature maintenance operation. The electromagnetic valve 58 of the second bypass channel 51 is opened. As a result, the amount of the refrigerant circulating in the low temperature side refrigerant flow path 37 and flowing into the low temperature side cooler 36 is reduced as compared with that during the temperature lowering operation. Further, during the low temperature maintenance operation, the output (cooling capacity) of the cooling unit 5 necessary for stabilizing the test environment temperature P at the low temperature set temperature Sc is derived in the calculation unit 83 of the control means 10, and according to this Thus, the opening degree of the electronic expansion valve 46 is adjusted. In the thermal fatigue evaluation apparatus 1 of the present embodiment, the opening degree of the electronic expansion valve 46 is adjusted between 30% and 50% during the low temperature maintenance operation.

  The control means 10 transmits a control signal to the heating unit 6 even in the low temperature maintenance operation so as to exert the heating capability, and suppresses the fluctuation of the test environment temperature P due to the control error of the cooling unit 5 to the minimum. More specifically, in this embodiment, the output of the heating unit 6 during the low temperature maintenance operation is adjusted between 20% and 30%.

  The thermal fatigue evaluation apparatus 1 adjusts the test environment temperature P in accordance with the control flow shown in FIG. More specifically, when a reliability evaluation test (temperature cycle test) is performed by the thermal fatigue evaluation apparatus 1, first, in step 1, test conditions are set via the setting means 20. That is, in step 1, information on the high temperature set temperature Sh and the low temperature set temperature Sc, the holding time T, the temperature change rate U, the cycle number N, and the operation mode is input to the input unit 80 via the control unit 10 and the data It is stored (set) in the storage unit 82.

  When the test conditions are set in step 1, the control flow moves to step 2 and the thermal fatigue evaluation test is started. That is, when the control flow shifts to step 2 and the thermal fatigue evaluation test is started, the control flow shifts to step 3, and the ambient temperature sensor 25 or the sample temperature sensor is selected according to the operation mode set in step 1. A detection signal related to the test environment temperature P detected by the control unit 26 is input to the input unit 80 of the control means 10. Thereafter, in step 4, a detection signal related to the test environment temperature P is input to the calculation unit 83, and output values required for the cooling unit 5 and the heating unit 6 are derived by calculation. Thereafter, the control flow proceeds to step 5.

  When the control flow shifts to step 5, the control means 10 adjusts the output of the cooling unit 5 and the heating unit 6 based on the result calculated by the calculation unit 83 according to the implementation status of the temperature cycle operation. That is, in step 5, the control means 10 opens the expansion valve 46 constituting the cooling unit 5, opens and closes the expansion valves 55 and 57, and opens the electromagnetic valve so as to exhibit the cooling capacity necessary for adjusting the test environment temperature P. The opening / closing of 47, 56, 58, 60 is controlled. Further, the control means 10 adjusts the output of the heating unit 6 so as to exhibit the heating ability necessary for adjusting the test environment temperature P.

  When the outputs of the cooling unit 5 and the heating unit 6 are adjusted in step 5, the control flow moves to step 6 and it is confirmed whether or not the test end timing has been reached. That is, in step 6 of the control flow, it is confirmed whether or not the above-described temperature cycle has been completed by the number N of cycles set in step 1. If it is determined in step 6 that the thermal fatigue evaluation apparatus 1 has not reached the test end timing, the control flow is returned to step 3 and the thermal fatigue evaluation test is continued. On the other hand, if it is determined in step 6 that the temperature cycle has already been performed for the number N of cycles, the series of control flow shown in FIG. 3 is completed, and the thermal fatigue evaluation test is completed.

  As described above, when the temperature cycle test is performed by changing the test environment temperature P so as to be proportional to the time within a predetermined error range (± 3 ° C.) in the temperature raising operation and the temperature lowering operation, the sample W Can faithfully reproduce the state in which creep deformation occurs.

  As described above, the thermal fatigue evaluation apparatus 1 of the present embodiment is configured to include the multi-component refrigeration cooling circuit 30 as the cooling unit 5. And the bypass flow paths 50-52 are provided in the low temperature side cooling system 31 for gas cooling which comprises the cooling circuit 30, and it bypasses the low temperature side cooler 36 by opening the solenoid valves 56, 58, 60. The refrigerant can be allowed to flow through. Further, the low temperature side cooling system 31 adjusts the amount of refrigerant flowing into the low temperature side cooler 36 by adjusting the opening degree of the electronic expansion valve 46 provided in the middle of the low temperature side refrigerant flow path 37, and gas The cooling capacity can be adjusted. Therefore, in the thermal fatigue evaluation apparatus 1, the test environment temperature P can be accurately adjusted by adjusting the output of the cooling unit 5 and the heating unit 6. In particular, according to the thermal fatigue evaluation apparatus 1, the rate of change in the test environment temperature P during the temperature rising / falling operation of the temperature cycle can be accurately adjusted according to the preset temperature change rate U. . Therefore, according to the thermal fatigue evaluation apparatus 1, the creep deformation and the like of the sample W can be accurately reproduced.

Moreover, in the thermal fatigue evaluation apparatus 1 of this embodiment, by operating the air blower which comprises the ventilation part 7, the structure which can supply in the state which adjusted the temperature of the wind speed of 2 m / sec or more in the vicinity of the sample W at least in the vicinity. are, during the implementation of the temperature cycle test, min 40 m ³ test chamber in a state of (per minute 0.27 m ³ relative to 1-liter test chamber 2) as air is temperature control in temperature control unit 3 2 is sent in. Furthermore, the thermal fatigue evaluation apparatus 1 raises or lowers the test environment temperature P at a predetermined temperature change rate U in proportion to time in a temperature raising operation and a temperature lowering operation performed during the temperature cycle test. It is possible to be configured. Therefore, in the thermal fatigue evaluation apparatus 1, the test environment temperature P can be smoothly changed in accordance with a preset temperature change rate U, and a state suitable for reproducing the creep deformation or the like of the sample W is obtained. Can do. Therefore, according to the thermal fatigue evaluation apparatus 1, the temperature cycle test (thermal fatigue evaluation test) against the temperature stress of the sample W can be performed quickly and accurately.

  Since the thermal fatigue evaluation apparatus 1 of this embodiment adjusts the test environment temperature P by introducing the temperature-adjusted air into the test chamber 2, the temperature cycle test of a plurality of samples W is performed at a time. be able to.

  In the above embodiment, the configuration in which the temperature of air at a wind speed of 2 m / second or more can be adjusted and introduced into the test chamber 2 over almost the entire test chamber 2 during the temperature cycle test is illustrated. However, the configuration may be such that air of 2 m / second or more can be supplied only in the vicinity of the sample, or a configuration in which an amount of air exceeding this range can be introduced into the test chamber 2. .

  Further, if a temperature cycle test is performed by the thermal fatigue evaluation apparatus 1, the rate of change in the test environment temperature P (temperature change rate U) can be adjusted with high accuracy, and the correlation between the strain rate and the strength of the sample W can be accurately determined. I can grasp it. Therefore, if a temperature cycle test is performed by the thermal fatigue evaluation apparatus 1, the reproducibility of the test is high, and data indicating the results of tests performed separately can be compared with each other with high accuracy.

  The above-described thermal fatigue evaluation apparatus 1 is used to switch the test environment temperature P from the high temperature set temperature Sh to the low temperature set temperature Sc, or from the low temperature set temperature Sc to the high temperature set temperature Sh, that is, the temperature during the temperature raising operation or the temperature lowering operation. A change rate U can be set, and the test environment temperature P can be changed according to the temperature change rate U. Therefore, according to the thermal fatigue evaluation apparatus 1, the test environment temperature P can be adjusted to a state suitable for reproduction such as creep deformation, and the temperature cycle test of the sample W can be performed with high accuracy.

  Moreover, in the thermal fatigue evaluation apparatus 1 of this embodiment, the temperature change rate U is made the same at the temperature raising operation and the temperature lowering operation. Therefore, according to the thermal fatigue evaluation apparatus 1, temperature stress can be applied to the sample W in a state suitable for reproduction of creep deformation and the like, and a highly reliable temperature cycle test can be performed.

  In the above embodiment, the configuration in which the temperature change rate U is the same during the temperature raising operation and during the temperature lowering operation is exemplified, but the present invention is not limited to this, and for example, reproduces the creep deformation of the sample W, etc. The temperature change rate U may be different between the temperature raising operation and the temperature lowering operation within a range that does not affect the temperature. The thermal fatigue evaluation apparatus 1 may be configured such that the temperature change rate U during the temperature raising operation and the temperature change rate U during the temperature lowering operation can be set separately, and can be set to different values as necessary. Good.

  As described above, in the thermal fatigue evaluation apparatus 1, the cooling capacity and the heating capacity required for the cooling unit 5 and the heating unit 6 in the control means 10 are adjusted in order to adjust the test environment temperature P according to the preset test conditions. It calculates and derives, and it is set as the structure which adjusts the output of the cooling part 5 or the heating part 6 based on this result. Here, in the thermal fatigue evaluation apparatus 1 of this embodiment, the arithmetic processing about the cooling capacity of the cooling unit 5 and the heating capacity of the heating unit 6 by the control means 10 is performed at a very short cycle of 1 second or less. Therefore, the thermal fatigue evaluation apparatus 1 can finely adjust the output adjustment of the cooling unit 5 and the heating unit 6 and can accurately adjust the test environment temperature P.

  In the above-described embodiment, the configuration in which the arithmetic processing for the outputs of the cooling unit 5 and the heating unit 6 by the control unit 10 is performed at a cycle of 1 second or less, but the present invention is not limited to this. The above-described arithmetic processing may be performed with a longer cycle.

  In the above embodiment, the configuration in which the holding time T during the high temperature maintaining operation and the holding time T during the low temperature maintaining operation are set to the same value is exemplified, but the present invention is not limited to this. It is good also as a structure which can set to each different value.

  In the above embodiment, in the temperature cycle test, the configuration for performing the high temperature maintenance operation and the low temperature maintenance operation for holding the test environment temperature P at the high temperature setting temperature Sh or the low temperature setting temperature Sc is exemplified. The present invention is not limited, and the high temperature maintenance operation and the low temperature maintenance operation may be omitted, that is, the holding time T may be zero.

  In the above embodiment, the configuration in which the temperature cycle starts from the temperature rising operation as shown in FIG. 4 is exemplified, but the present invention is not limited to this, and for example, a series of operations (temperature lowering operation) in which the temperature cycle starts from the temperature lowering operation. → low temperature maintenance operation → temperature rise operation → high temperature maintenance operation).

  In the above embodiment, the cooling unit 5 and the heating unit are regarded as the test environment temperature P, which is the ambient temperature in the test chamber 2 detected by the ambient temperature sensor 25 or the temperature of the sample W itself detected by the sample temperature sensor 26. However, the present invention is not limited to this, and can be obtained by substituting the detected temperatures of both the ambient temperature sensor 25 and the sample temperature sensor 26 into a predetermined arithmetic expression, for example. A value may be used as the test environment temperature P, or a detection temperature of one of the ambient temperature sensor 25 and the sample temperature sensor 26 may be adopted as the test environment temperature P depending on conditions.

  Although the thermal fatigue evaluation apparatus 1 illustrated the structure which supplies the air in which the temperature was adjusted in the temperature control part 3 to the test room 2, the structure which adjusts the temperature of other gas instead of air and supplies it to the test room 2 It is good.

  In the above embodiment, the low temperature side cooler 36 is adjusted by adjusting the electronic expansion valve 46 and the electromagnetic valves 47, 56, 58, 60 provided in the cooling circuit 30 to adjust the amount of refrigerant flowing into the low temperature side cooler 36. However, the present invention is not limited to this. More specifically, the thermal fatigue evaluation apparatus 1 adjusts the output of, for example, the low temperature side compressor 41, or provides a plurality of low temperature side compressors 41 in the low temperature side cooling system 31, and adjusts the number of operating units for cooling capacity. May be adjusted.

  Moreover, in the said embodiment, although the cooling part 5 was comprised by the single cooling circuit 30, this invention is not limited to this, For example, multiple things equivalent to the cooling circuit 30 are provided. The number of cooling circuits 30 that operate according to the cooling capacity required for cooling the air may be adjusted.

  The above-described cooling unit 5 has a configuration in which the cooling circuit 30 is thermally connected to the low temperature side cooling system 31 and the high temperature side cooling system 32 via the cascade capacitor 35, but the present invention is not limited to this. For example, instead of using a cascade condenser 35 or the like, the cooling system is further thermally connected in multiple stages, or the low temperature side cooling system 31 is thermally connected to the high temperature side cooling system 32 using the cascade condenser 35. In addition, the condenser may be arranged at a position corresponding to the cascade condenser 35, and only a single cooling system may be used.

  In the above-described embodiment, in the series of temperature cycle operations, an example is shown in which the transition from the timing at which the temperature raising operation is completed to the high temperature maintenance operation or the transition from the timing at which the temperature lowering operation is completed to the low temperature maintenance operation is given. However, the present invention is not limited to this. For example, a configuration may be adopted in which a high-temperature maintenance operation or a low-temperature maintenance operation is performed after a predetermined delay time has elapsed since the completion of the temperature raising operation or the temperature lowering operation. According to such a configuration, the time during which the sample is exposed to the environment of the high temperature set temperature Sh or the low temperature set temperature Sc during the high temperature maintenance operation or the low temperature maintenance operation can be surely set to the holding time T or more, and thermal fatigue evaluation The accuracy of the test can be further improved.

  The thermal fatigue evaluation apparatus 1 described above is capable of setting the temperature change rate U within a range of 1 ° C. to 30 ° C. per minute. However, when the thermal fatigue evaluation method is carried out, the temperature change rate U is set per minute. If it is set to be proportional in the range of 5 ° C. to 20 ° C. and changed, the period required for the temperature cycle test can be minimized while ensuring the accuracy of the temperature cycle test.

  The thermal fatigue evaluation apparatus 1 described above can set the temperature change rate U within a range of 1 ° C. to 30 ° C. per minute, but is proportional to the temperature change rate U within a range of 5 ° C. to 20 ° C. per minute. A configuration that can be set and changed is also possible. Even with this configuration, the temperature cycle test can be performed with the same accuracy as the thermal fatigue evaluation apparatus 1 of the above embodiment, and the period required for the temperature cycle test can be minimized.

  Then, about the test result which compared the state of the temperature change of the sample W when a temperature cycle test was implemented with the above-mentioned thermal fatigue evaluation apparatus 1 and when a thermal cycle test was implemented with the conventional thermal cycle test apparatus. explain.

FIG. 5 is a graph showing the temperature change of the sample W when the thermal fatigue evaluation device 1 and the conventional thermal cycle testing device are operated under the following test conditions, respectively. Note that the temperature change rate U cannot be set in the conventional thermal cycle testing apparatus.
Test conditions Low temperature setting temperature Sc = −40 ° C.
High temperature set temperature Sh = 125 ° C
Temperature change rate U = 10 ° C / min

  When the temperature cycle test was performed by the thermal fatigue evaluation apparatus 1, the temperature change (temperature gradient) during the temperature raising operation and the temperature lowering operation could be made substantially uniform as shown in FIG. Further, when the temperature cycle test was performed by the thermal fatigue evaluation apparatus 1, the temperature error of the sample W (test environment temperature P) was within a range of ± 2 ° C. and was extremely stable.

  On the other hand, when the thermal cycle test was performed using the conventional thermal cycle test apparatus, the temperature change during the temperature raising operation and the temperature lowering operation was not uniform as shown in FIG. In addition, when the test was carried out using the conventional thermal cycle apparatus, the temperature of the sample W (test environment temperature P) was abruptly changed or the change was gradual, and thus it was unstable.

  Subsequently, when the temperature cycle test is performed by the thermal fatigue evaluation apparatus 1 described above, the temperature change rate U in the temperature raising operation (hereinafter referred to as the temperature rise rate U1) and the temperature change rate U in the temperature lowering operation (hereinafter referred to as the temperature change rate U). The test results when the temperature change rate U2) is the same will be described.

In this embodiment, as shown in FIG. 6, a copper electric circuit pattern 91 is brazed on a printed circuit board 90, and an electronic component 92 is brazed with solder 93 on the electric circuit pattern 91 as a sample W. The temperature cycle test was conducted under the following test conditions. The thermal expansion coefficient of the printed circuit board 90 constituting the sample W employed in the temperature cycle test of the present embodiment is 60 to 80 [ppm / ° C.], and the thermal expansion coefficient of the electric circuit pattern 91 is 17 [ppm / ° C. ]. The thermal expansion coefficient of the electronic component 92 is 8 [ppm / ° C.], and the thermal expansion coefficient of the solder 93 is 25 [ppm / ° C.].
Test conditions High temperature set temperature Sh = + 125 ° C
Low temperature setting temperature Sc = −40 ° C.
Rate of temperature change U1 = 16 ° C / min
Rate of temperature change U2 = 16 ° C / min
Retention time T = 20 minutes
Number of cycles N = 3000

  An electron micrograph (see FIG. 7A) in which the portion where the solder 93 is broken by performing the temperature cycle test under the above conditions and the portion where the solder 93 is broken by actually using the sample W are enlarged. Comparing with the electron micrograph (see FIG. 7B), it was found that both were in the same deterioration state. Accordingly, it has been found that if the temperature cycle test is performed by the thermal fatigue evaluation apparatus 1, it is possible to faithfully reproduce the state in which the solder 93 constituting the sample W is actually deformed or broken.

It is a conceptual diagram which shows typically the structure of the thermal fatigue evaluation apparatus concerning one Embodiment of this invention. It is an operation principle figure of the cooling system employ | adopted in the thermal fatigue evaluation apparatus shown in FIG. It is a flowchart which shows operation | movement of the thermal fatigue evaluation apparatus shown in FIG. It is a timing chart which shows the operation state of the thermal fatigue evaluation apparatus shown in FIG. 1, (a) is a timing chart which shows transition of test environment temperature, (b) is a timing chart which shows transition of the output of a cooling part, ( c) is a timing chart showing the transition of the opening degree of the electronic expansion valve, and (d) is a timing chart showing the transition of the output of the heating unit. It is a graph which shows transition of the test environment temperature at the time of implementing the temperature cycle test by the thermal fatigue evaluation apparatus shown in FIG. 1, and the thermal cycle test by the conventional thermal cycle test apparatus. It is a schematic diagram which shows the structure of the sample employ | adopted in the Example of this invention. (A) is the electron micrograph which expanded the part which the solder fracture | ruptured by implementing a temperature cycle test, (b) is the electron micrograph which expanded the part which the solder fracture | ruptured by actually using a sample. is there.

Explanation of symbols

1 Thermal fatigue evaluation device 2 Test room 3 Temperature control section (temperature control means)
5 Cooling part (cooling means)
6 Heating part (heating means)
7 Blower (blower means)
10 Control means 25 Atmospheric temperature sensor 26 Sample temperature sensor 30 Cooling system 31 Low temperature side cooling system 32 High temperature side cooling system 35 Cascade condenser 36 Low temperature side cooler 37 Low temperature side refrigerant flow path 41 Low temperature side compressor 46 Expansion valve (flow rate variable expansion) Valve, electronic expansion valve)
47, 60 Solenoid valve 56 Solenoid valve (first bypass valve)
58 Solenoid valve (second bypass valve)
50, 51, 52 Bypass flow path 65 High temperature side refrigerant flow path 83 Calculation unit W Sample Sh High temperature set temperature Sc Low temperature set temperature U Temperature change rate P Test environment temperature

Claims (15)

It is a thermal fatigue evaluation method due to thermal stress and creep deformation caused by the difference in thermal expansion coefficient of samples such as electric parts and materials,
By adjusting the temperature of the gas to which the sample is exposed, the ambient temperature to which the sample is exposed and / or the temperature of the sample is within a predetermined error range over time from a set temperature lower than room temperature to a set temperature higher than room temperature. Temperature rising operation that changes in proportion to
By adjusting the temperature of the gas to which the sample is exposed, the ambient temperature to which the sample is exposed and / or the temperature of the sample is within a predetermined error range over time from a set temperature higher than room temperature to a set temperature lower than room temperature. A thermal fatigue evaluation method characterized by performing a temperature cycle operation including a temperature lowering operation that is changed in proportion to a predetermined cycle. A high temperature maintaining operation in which the temperature cycle operation maintains the ambient temperature to which the sample is exposed and / or the temperature of the sample at a set temperature higher than room temperature after the temperature rising operation;
The thermal fatigue evaluation method according to claim 1, further comprising: a low temperature maintaining operation for maintaining an ambient temperature to which the sample is exposed and / or a temperature of the sample at a set temperature lower than room temperature after the temperature lowering operation. Set the set temperature lower than room temperature in the range of -70 ° C to 0 ° C,
Set the set temperature higher than room temperature in the range of 60 ℃ ~ 180 ℃,
2. The ambient temperature to which the sample is exposed during the temperature raising operation and the temperature lowering operation, or the temperature of the sample is set to be proportional in the range of 1 ° C. to 30 ° C. per minute and changed. 2. The thermal fatigue evaluation method according to 2.   The temperature according to any one of claims 1 to 3, wherein an error range of the atmospheric temperature and / or the temperature of the sample to which the sample is exposed during the temperature raising operation and the temperature lowering operation is + 5 ° C to -5 ° C. Fatigue evaluation method.   The ratio of the temperature change of the ambient temperature to which the sample is exposed during the temperature raising operation and the temperature lowering operation, or the ratio of the temperature change of the sample is substantially different between the temperature raising operation and the temperature lowering operation. The thermal fatigue evaluation method according to claim 1, wherein the thermal fatigue evaluation method is the same. By arranging the sample in a predetermined test chamber and supplying a temperature-controlled gas into the test chamber, the ambient temperature and / or the sample temperature to which the sample is exposed are adjusted,
The thermal fatigue evaluation method according to claim 1, wherein the wind speed in the vicinity of the sample is adjusted to be at least 2 m / second or more. A test chamber capable of accommodating a sample, temperature adjusting means for adjusting the temperature of the gas supplied into the test chamber, and air blowing means capable of supplying gas to the test chamber,
By introducing a gas whose temperature has been adjusted in the temperature control means into the test chamber, the ambient temperature in the test chamber in which the sample is accommodated and / or the temperature of the sample from a set temperature higher than room temperature to a set temperature lower than room temperature, Alternatively, a thermal fatigue evaluation device capable of switching from a set temperature lower than room temperature to a set temperature higher than room temperature,
The atmosphere temperature in the test chamber and / or the temperature of the sample can be adjusted within the range of -70 ° C to 180 ° C,
A temperature raising operation for switching the ambient temperature in the test chamber and / or the temperature of the sample from a set temperature lower than room temperature to a set temperature higher than room temperature,
A high temperature maintaining operation for maintaining the ambient temperature in the test chamber and / or the temperature of the sample at a set temperature higher than room temperature;
A temperature lowering operation for switching the ambient temperature in the test chamber and / or the temperature of the sample from a set temperature higher than room temperature to a set temperature lower than room temperature;
It is possible to perform a temperature cycle operation including a low-temperature maintenance operation that maintains the ambient temperature in the test chamber and / or the temperature of the sample at a set temperature lower than room temperature,
The ambient temperature in the test chamber and / or the rate of temperature change of the sample can be set to be proportional within the range of 1 ° C to 30 ° C per minute, and can be changed within a predetermined error range.
The execution time of the high temperature maintenance operation and the low temperature maintenance operation can be set,
The number of repetitions of temperature cycle operation can be set to 1 or more,
A thermal fatigue evaluation apparatus characterized in that the ambient temperature to which the sample is exposed during the temperature raising operation and the temperature lowering operation or the rate of change in the temperature of the sample can be set within a range of 1 ° C to 30 ° C per minute. As the temperature control means, a cooling means capable of cooling the gas supplied into the test chamber and a heating means capable of heating the gas are employed,
The cooling means includes a refrigerant flow path through which a refrigerant flows and a cooler, and includes a cooling system for gas cooling that can cool the gas supplied to the test chamber by the cooler.
The cooling system for cooling the gas has a bypass channel that can flow the refrigerant flowing through the refrigerant channel so as to bypass the cooler, and adjusts the amount of the refrigerant that bypasses the bypass channel. The amount of refrigerant supplied to the cooler can be adjusted by
While adjusting the cooling capacity of the cooling means by adjusting the amount of refrigerant bypassing to the bypass flow path side in the cooling system for gas cooling according to the change in the ambient temperature in the test chamber and / or the temperature change of the sample, The thermal fatigue according to claim 7, wherein the heating means is operated so as to supplement the amount of heat excessively cooled with respect to the set value of the ambient temperature and / or the set value of the temperature of the sample. Evaluation device. The high temperature maintenance operation is started after a predetermined delay time from the time when the set temperature higher than room temperature is reached by the temperature raising operation,
9. The thermal fatigue evaluation apparatus according to claim 8, wherein the low temperature maintaining operation is started after a predetermined delay time from the time when the set temperature lower than room temperature is reached by the temperature lowering operation. As the temperature control means, a cooling means capable of cooling the gas supplied into the test chamber and a heating means capable of heating the gas are employed,
The cooling means includes a refrigerant flow path through which a refrigerant flows and a cooler, and includes a cooling system for gas cooling that can cool the gas supplied to the test chamber by the cooler.
The cooling system for cooling the gas includes a compressor, first and second bypass channels that can flow the refrigerant flowing through the refrigerant channel so as to bypass the cooler, and the refrigerant channel. Provided, a variable flow rate expansion valve capable of adjusting the amount of refrigerant flowing into the cooler, a first bypass valve capable of opening and closing the first bypass flow path, and provided in the first bypass flow path, A temperature-type expansion valve that opens and closes or changes in opening according to the temperature of the refrigerant flowing in the cooling system, a second bypass valve that can open and close the second bypass flow path, and a second bypass flow path And a capacity expansion valve that adjusts the capacity according to the fluctuation of the cooling load,
By adjusting the variable flow rate expansion valve, the amount of refrigerant supplied to the cooler can be adjusted,
A temperature raising operation for switching the ambient temperature in the test chamber and / or the temperature of the sample from a set temperature lower than room temperature to a set temperature higher than room temperature,
A high temperature maintaining operation for maintaining the ambient temperature in the test chamber and / or the temperature of the sample at a set temperature higher than room temperature;
A temperature lowering operation for switching the ambient temperature in the test chamber and / or the temperature of the sample from a set temperature higher than room temperature to a set temperature lower than room temperature;
It is possible to perform a temperature cycle operation including a low-temperature maintenance operation that maintains the ambient temperature in the test chamber and / or the temperature of the sample at a set temperature lower than room temperature,
During the temperature raising operation, the first and second bypass valves are opened, the opening of the variable flow rate expansion valve is adjusted to 10% or less, and the output of the heating means is adjusted within the range of 60 to 100%. And
During the high temperature maintenance operation, the output of the heating means is adjusted within a range of 30 to 50% while the first and second bypass valves are opened and the opening of the variable flow rate expansion valve is adjusted to 10% or less. And
During the temperature lowering operation, the first and second bypass valves are closed, the opening of the variable flow rate expansion valve is adjusted within the range of 50 to 100%, and the output of the heating means is within the range of 0 to 20%. Adjusted with
During the operation for maintaining the low temperature, the first bypass valve is closed, the second bypass valve is opened, and the opening of the variable flow rate expansion valve is adjusted within a range of 30 to 50%. The thermal fatigue evaluation apparatus according to any one of claims 7 to 9, wherein the output of is adjusted within a range of 20 to 30%. It is possible to set the ratio of temperature change when switching the setting value of the ambient temperature of the test room or the setting value of the sample temperature.
The amount of refrigerant bypassing to the bypass channel side is adjusted based on a set value of the temperature change ratio, a set value of the ambient temperature of the test chamber, and / or a set value of the temperature of the sample. Item 11. The thermal fatigue evaluation apparatus according to any one of Items 7 to 10.   The thermal fatigue evaluation apparatus according to any one of claims 8 to 11, wherein the gas can be supplied so that the wind speed in the vicinity of the sample is at least 2 m / second or more. A temperature raising operation for switching the ambient temperature of the test chamber in which the sample is accommodated and / or the temperature of the sample from a set temperature lower than room temperature to a set temperature higher than room temperature,
A high temperature maintaining operation for maintaining the ambient temperature of the test chamber in which the sample is accommodated and / or the temperature of the sample at a set temperature higher than room temperature;
A temperature lowering operation for switching the ambient temperature of the test chamber in which the sample is accommodated and / or the temperature of the sample from a set temperature higher than room temperature to a set temperature lower than room temperature;
It is possible to perform a temperature cycle test in which the ambient temperature of the test chamber in which the sample is accommodated and / or the low-temperature maintenance operation for maintaining the temperature of the sample at a set temperature lower than room temperature is sequentially performed,
The thermal fatigue evaluation apparatus according to any one of claims 7 to 12, wherein a rate of temperature change is substantially the same when the temperature raising operation is performed and when the temperature lowering operation is performed.   An error in the ambient temperature of the test chamber and / or the sample temperature at the time of the temperature raising operation and the temperature lowering operation is +5 with respect to the set value of the test chamber ambient temperature and / or the set temperature of the sample. The thermal fatigue evaluation apparatus according to any one of claims 7 to 13, wherein the thermal fatigue evaluation apparatus can be adjusted within a range of ° C to -5 ° C. Detect the ambient temperature of the test chamber or the temperature of the sample, calculate and derive the heating capacity and cooling capacity required for the heating means and cooling means based on the temperature, and based on the calculation results, It adjusts the output value of the cooling means,
The thermal fatigue evaluation apparatus according to claim 7, wherein the calculation is performed at a cycle of 1 second or less.