JP2013148370A - Lifetime evaluation device with temperature history, and iron head temperature measurement device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lifetime evaluation device with a temperature history capable of rationally determining the lifetime of a temperature sensor in an iron head temperature measurement device.SOLUTION: A lifetime evaluation device includes: a temperature sensor 201; time measurement means (a timer 207) for measuring a lapsed time for the detection of temperature when the temperature sensor detects a fixed level or more temperature; evaluation value calculation means (an arithmetic part 202) for calculating an evaluation value to be greater as temperature is higher and a time is longer on the basis of both data of the temperature detected by the temperature sensor and the time measured by the time measurement means; integration means (the arithmetic part 202) for calculating an integration value of the evaluation value whenever the temperature sensor detects a fixed level or more temperature; storage means (a storage part 203) for storing by updating an integration value calculated by the integration means; and alarm means (the arithmetic part 202) for generating an alarm signal when the integration value of the evaluation value exceeds a predetermined lifetime value.

Description

  The present invention includes, for example, a life evaluation device based on a temperature history that can be used for life determination such as a temperature sensor for measuring the tip temperature of a soldering iron, and such a life evaluation device. The present invention relates to a tip temperature measuring device that can determine the life of a temperature sensor that measures the tip temperature.

  When soldering between electronic circuit board terminals with jumper wires, etc., it is important to control the temperature of the soldering iron tip. For this purpose, the temperature of the iron tip is measured by a temperature measuring device. . As a conventional soldering iron tip temperature measuring device, the one described in Patent Document 1 is known.

  In the tip temperature measuring device described in Patent Document 1, two dissimilar metal materials forming a thermocouple are arranged apart from each other, the dissimilar metal materials are brought into electrical contact with the tip, and the iron is used. The tip temperature is detected.

  However, this measuring apparatus has a problem that it is difficult to perform measurement because the tip needs to be in contact with both of the dissimilar metal materials separated from each other. Therefore, a sensor chip made of a metal material having high wettability with respect to solder is used as a member to contact the tip, and this sensor chip is mounted on a support made of a metal strip, and a thermocouple is mounted on the sensor chip. A tip temperature measuring device has been devised that uses a temperature sensor to which the temperature measuring contacts are joined.

Japanese Patent Laid-Open No. 10-144442

  By the way, when the tip temperature is measured by a temperature sensor having a sensor chip that contacts this type of tip, the wear of the sensor chip proceeds by repeatedly bringing the tip of the tip into contact with the sensor chip. Therefore, if a certain number of times is used, the temperature sensor must be replaced. For example, it has been found that the sensor chip of the temperature sensor of the tip temperature measuring device dissolves in tin, which is a component of solder, so that the sensor chip gradually becomes thin. . It has been found that the wear in this case is proportional to temperature and time.

  Until now, the temperature sensor was replaced by judging the approximate lifetime by counting the number of measurements. However, in such a case, there is a problem in that it is troublesome to count the number of times of measurement, and it is not possible to reasonably manage the life by counting incorrectly and counting the life early or late. It was.

  In consideration of the above circumstances, the present invention includes, for example, a life evaluation device based on a temperature history that can reasonably determine the life of a temperature sensor of a tip temperature measuring device, and such a life evaluation device. An object of the present invention is to provide a tip temperature measuring device capable of determining the life of a temperature sensor that measures the tip temperature.

The present invention employs the following means in order to solve the above problems.
That is, the lifetime evaluation device based on the temperature history of the invention of claim 1 is a temperature sensor that detects the temperature of the measurement object, and an elapsed time during which the temperature sensor detects the temperature when the temperature sensor detects a temperature higher than a certain level. A time measurement means for measuring the evaluation value, and an evaluation value calculation for calculating an evaluation value that increases as the temperature is higher and the time is longer, based on both data detected by the temperature sensor and the time measured by the time measurement means Means, an integration means for calculating an integrated value of the evaluation value every time the temperature sensor detects a temperature above a certain level, a storage means for updating and storing the integrated value calculated by the integration means, and an integration of the evaluation value And an alarm means for generating an alarm signal when the value exceeds a preset life value. Thereby, the lifetime according to the temperature history of the measurement object can be easily and reasonably determined.

  The invention of claim 2 further comprises reset means for resetting the accumulated value stored in the storage means to zero, and life value setting means for inputting an arbitrary life value as the life value. Thereby, the lifetime value can be arbitrarily set in advance. In addition, the lifetime can be determined many times by resetting the integrated value.

  A tip temperature measuring device according to a third aspect of the present invention includes the lifetime evaluation device according to the temperature history according to the first or second aspect, wherein the tip temperature is adjusted by contacting the tip as the temperature sensor. A temperature sensor that can be detected is provided, and an object for life evaluation is the temperature sensor itself. Thereby, the lifetime determination of the temperature sensor which contacts the tip and measures the temperature of the tip can be easily and rationally performed.

  According to the first aspect of the invention, the evaluation value corresponding to the temperature history is calculated using the temperature and time as parameters, and the alarm signal is generated when the integrated value of the evaluation value exceeds the lifetime value. The lifetime of the measurement object can be easily and reasonably determined.

  According to the invention of claim 2, since the life value can be arbitrarily set in advance by the life value setting means, the replacement time can be freely selected according to the user's condition. Further, the lifetime can be determined many times by resetting the integrated value by the reset means.

  According to the third aspect of the present invention, it is possible to easily and rationally determine the life of a contact-type temperature sensor that contacts the soldering iron tip and measures the temperature of the tip.

BRIEF DESCRIPTION OF THE DRAWINGS It is a block diagram of the tip temperature measuring apparatus to which the lifetime evaluation apparatus of embodiment of this invention is applied, (a) is a top view, (b) is a left view, (a) It is an Ic-Ic arrow sectional drawing. is there. (A) is a plan view of a temperature sensor used in the tip temperature measuring device, (b) is an enlarged side sectional view of a fixing portion of the temperature sensor in the tip temperature measuring device, and (c) constitutes the temperature sensor. It is a principal part enlarged view which shows the relationship between the temperature measuring contact of a sensor chip, a thermocouple, and a metal-mesh support. It is explanatory drawing of how to make the said temperature sensor. It is a block diagram which shows the structure of the lifetime evaluation apparatus of the temperature sensor contained in the control apparatus of the said tip temperature measuring apparatus. It is a flowchart which shows the example of the flow of control processing of the lifetime evaluation apparatus.

Hereinafter, a tip temperature measuring device to which a life evaluation device of an embodiment of the present invention is applied will be described with reference to the drawings.
FIG. 1 is a block diagram of a tip temperature measuring device equipped with a temperature sensor. The tip temperature measuring device 1 includes a tip temperature measuring device main body 10 and a temperature sensor 100. The tip temperature measuring device main body 10 has a control device (not shown) built in a case 11 made of a resin molded product, and has a measuring unit 12 on one side of the surface of the case 11 and is operated on the other side. Part 13 is provided.

  The operation unit 13 includes a display unit 4 for displaying the detected temperature, a power switch 5 for turning on / off the power of the apparatus, and a hold / instruction for holding and displaying the measured peak value and switching various modes. A mode switch 6 and a sensor reset switch 7 for resetting the integrated value of the evaluation values to zero when the life of the temperature sensor 100 is evaluated are provided.

  The measurement unit 12 is surrounded by an annular scattering prevention wall 15. When the tip temperature of the soldering iron H is measured by bringing the tip of the soldering iron H into contact with the temperature sensor 100 set on the measuring unit 12, the scattering prevention wall 15 scatters solder and flux to the outside of the measuring unit 12. This is a bank-like raised wall for preventing the temperature sensor 100 and is also provided to protect the temperature sensor 100.

  On the inner bottom surface of the measurement unit 12 surrounded by the scattering prevention wall 15, two support pins 21 and 22 are erected in parallel upward at a distance from each other. Of the two support pins 21, the one far from the operation unit 13 is a fixed support pin 21, and the one near the operation unit 13 is a movable support pin 22. The movable support pin 22 is provided so as to be movable in a direction in which the distance between the pair of support pins 21 and 22 is adjusted (that is, a direction along a straight line connecting the two support pins 21 and 22).

  As shown in FIG. 2B, the inner bottom surface of the measurement unit 12 is configured with a flat bottom wall 17, and the base end portion 21 b of the support pin 21 on the fixed side is inserted into the bottom wall 17 and fixed. Has been. Further, a pin support portion 37 of the tension lever 30 assembled to the case 11 is disposed at a portion that supports the base end portion 22 b of the movable support pin 22. The tension lever 30 is a component made of a resin molded product separate from the case 11.

  On the bottom wall 17 of the measuring part 12 of the case 11, the pin support part 37 of the tension lever 30 can be moved along the moving direction of the support pin 22 on the movable side, and the upper movable gap 18 and the upper side. A movable space 19 is provided. The lower movable gap 18 is covered with a slide wall 38 that prevents the pin support portion 37 from falling off the movable gap 18, so that solder and flux do not enter the inside of the case 11 through the movable gap 18. Yes. In addition, the entrance of the movable space 19 is covered with a rubber washer 40 fitted with the support pin 22 so that solder and flux do not enter the inside of the case 11 through the movable space 19.

  The base end portion 22 b of the movable support pin 22 is inserted and fixed to the pin support portion 37 of the tension lever 30. The two support pins 21 and 22 on the fixed side and the movable side have the same shape, the heads 21a and 22a at the tip are formed in a conical shape, and the constricted portions 21c and 22c below the two are connected to both ends of the temperature sensor 100. The mounting portions 108 and 109 are fitted and held. Further, the base end sides of the support pins 21 and 22 are electrically connected to a control device (not shown) via electrical connection portions 26 and 27. In addition, the inner bottom surface of the measuring unit 12 is covered with a heat shield plate 50 made of aluminum or the like in order to protect the bottom wall 17 of the resin case 11.

  As shown in FIG. 1A, the tension lever 30 that supports the movable support pin 22 has a lever operation portion 31 exposed on the side surface of the case 11, and the lever operation portion 31 and the pin support portion 37. The movable support pin 22 is attached to the case 11 so that it can be rotated within a plane in which the movable support pin 22 moves. Further, between the tension lever 30 and the case 11, a pin 33 and a long hole 34 that are slidably engaged with each other are provided for smooth rotation of the tension lever 30.

  Further, the tension lever 30 is biased in one rotational direction by a spring (biasing means) 35, whereby the movable support pin 22 opens a distance between the support pins 21 and 22 (arrow). A direction). Thus, when the lever operating portion 31 is pressed in the direction of arrow B, the tension lever 30 rotates in the direction of arrow C against the urging force of the spring 35, so that the support pin 22 on the movable side is It moves in the direction of arrow D against the urging force.

  Here, the tension lever 30 having the pin support portion 37 and the lever operation portion 31 and the rotation shaft 32 that rotatably supports the tension lever 30 are supported against the urging force of the spring 35 on the movable side. A pin moving operation mechanism is configured to move 22 in a direction to reduce the distance between the support pins 21 and 22.

Next, the temperature sensor 100 will be described in detail with reference to FIG.
The temperature sensor 100 detects the tip temperature of the soldering iron H and outputs an electric signal. The belt-plate-shaped wire mesh support 101 (for example, the wire diameter is 0.02 to 0.2 mm, 50 Sensor chip 102 made of a metal (for example, a metal with high solder wettability such as white or iron) that contacts the soldering iron H tip, A thermocouple 103 composed of a pair of dissimilar metal conductors 104 and 105 in which a temperature measuring contact 106 is joined to the sensor chip 102, and a pair of support pins 21 of the tip temperature measuring device main body 10 at both ends of the wire mesh support 101, 22 are provided with perforated mounting portions 108 and 109 provided so as to be fitted to each of them.

  The dissimilar metal conductors 104 and 105 constituting the thermocouple 103 are covered with a sleeve 107 at portions other than both ends. As shown in FIG. 2C, a sensor chip 102 is disposed on the front surface in the longitudinal direction of the wire mesh support 101, and a temperature measuring contact 106 of a thermocouple 103 is disposed on the rear surface. By welding (spot welding), the sensor chip 102, the wire mesh support 101, and the temperature measuring contact 106 of the thermocouple 103 are integrally joined. The wire mesh support 101 is held in a stretched state by being supported by the support pins 21 and 22 of the tip temperature measuring device main body 10 by mounting portions 108 and 109 provided at both ends in the longitudinal direction.

Next, how to make the temperature sensor 100 and the detailed configuration of the attachment portions 108 and 109 at both ends will be described.
The perforated attachment portions 108 and 109 at both ends of the temperature sensor 100 are made of resin (for example, acrylic) disk-like plates in which projecting pieces 110a are joined to both ends of the wire mesh support 101 by thermal welding. A perforated fixed plate 110, a metal (for example, SUS) washer 111 that is overlapped with the perforated fixed plate 110, and ends of the metal conductors 104 and 105 of the thermocouple 103 are joined by electric welding, and a washer. A cylindrical Ni-plated metal eyelet 112 that crimps the washer 111 and the perforated fixed plate 110 through the through hole 111 and the perforated fixed plate 110 and the fixed plate 110 is heat-welded. And heat shrinkable tubes 113 and 114 mounted so as to cover the portion. The heat shrinkable tubes 113 and 114 on both sides are color-coded to prevent reverse mounting of the temperature sensor 100 on the support pins 21 and 22 of the tip temperature measuring device main body 10.

  When making this temperature sensor 100, as shown in FIG. 3, the wire-mesh support body 101 and the fixed plate 110 are prepared and joined by thermal welding. Further, the wire mesh support 101, the sensor chip 102, and the temperature measuring contact 106 of the thermocouple 103 are joined by electric welding. Further, the end portions of the metal conductive wires 104 and 105 of the thermocouple 103 are electrically welded to the washer 111, and the washer 111 and the fixed plate 110 are crimped by the eyelet 112. Finally, the heat welding portion of the fixed plate 110 is covered with the heat shrinkable tubes 113 and 114 and heated to shrink the heat shrinkable tubes 113 and 114. Thus, the temperature sensor 100 is completed.

  When the temperature sensor 100 is attached to the tip temperature measuring device main body 10, the lever operating portion 31 of the tension lever 30 is pressed as indicated by an arrow B, and the movable support pin 22 is moved inward (in the direction of the arrow D). ) And the through holes of the eyelets 112 of the mounting portions 108 and 109 at both ends of the temperature sensor 100 are fitted into the support pins 21 and 22. Next, when the lever operating part 31 is released in this state, the support pin 22 on the movable side is moved in the direction (in the direction of the arrow A) to open the distance between the support pins 21 and 22 by the force of the spring 35, thereby supporting the wire mesh. The temperature sensor 100 is held in a state where tension is applied to the body 101.

  In this state, the power switch 5 is turned on, and the tip of the soldering iron H is brought into contact with the sensor chip 102 of the temperature sensor 100. Then, the detected temperature is displayed on the display unit 4. By visually recognizing it, the operator can check the tip temperature.

  In the temperature sensor 100 of the tip temperature measuring device 1, a sensor chip (a metal chip having high wettability with respect to solder) 102 bonded to a temperature measuring contact 106 of a thermocouple 103 on a wire mesh support 101 is provided. Since it is mounted, the escape of heat through the member that supports the sensor chip 102 can be suppressed as much as possible. In other words, the wire mesh can reduce the substantial cross-sectional area of the path through which heat escapes, compared to a metal plate having the same outer dimensions and a metal plate with slits to reduce the substantial cross-sectional area. The amount of heat released from the sensor chip 102 through the support 101 can be reduced. Therefore, the temperature of the tip can be accurately measured by the thermocouple 103 via the sensor chip 102.

  In addition, since the belt-shaped wire mesh is used as the support for the sensor chip 102, the sensor chip 102 can be held in a stable posture, and the tip can be easily brought into contact with the small sensor chip 102. Therefore, it becomes easy to measure.

  Further, since the temperature measuring contact 106 of the sensor chip 102 and the thermocouple 103 and the wire mesh support 101 are integrally joined by electric welding, the strength and integrity of the sensor main part can be increased. The temperature can be measured with high accuracy.

  In addition, since both ends of the wire mesh support 101 are provided with perforated mounting portions 108 and 109 that respectively fit to the pair of support pins 21 and 22 of the tip temperature measuring device main body 10, The temperature sensor 100 can be easily set on the tip temperature measuring device main body 10 simply by fitting the mounting portions 108 and 109 to the support pins 21 and 22 of the tip temperature measuring device main body 10. Exchange is also easy.

  Further, both ends of the metal mesh support 101 are not made of metal but are joined to the perforated fixed plate 110 made of resin having low thermal conductivity, so that the tip is passed through both ends of the metal mesh support 101. The amount of heat that escapes to the support pins 21 and 22 side of the temperature measuring device main body 10 can be reduced. In addition, a conduction path from the thermocouple 103 to the tip temperature measuring device main body 10 is ensured through a washer 111 overlaid on the fixed plate 110 and a grommet 112 that crimps the washer 111 and the fixed plate 110. So stable measurement can be guaranteed.

  Moreover, according to the tip temperature measuring apparatus 1 having the above-described configuration, at least one of the pair of support pins 21 and 22 is provided movably in a direction in which the distance between the pair of support pins 21 and 22 is adjusted. Therefore, the perforated mounting portions 108 and 109 of the temperature sensor 100 are fitted to the support pins 21 and 22 in a state where the distance between the support pins 21 and 22 is shortened, and in this state, between the support pins 21 and 22 By adjusting the distance in the opening direction, the wire mesh support 101 of the temperature sensor 100 can be easily maintained in a tensioned state (with tension), and the sensor chip 102 can be stably supported. it can.

  Further, in the state where the distance between the support pins 21 and 22 is shortened by operating the lever operation portion 31 of the tension lever 30 constituting the pin moving operation mechanism, the hole mounting portion 108 of the temperature sensor 100 is attached to each support pin 21 and 22. 109, and in this state, the operation of the lever operating portion 31 is stopped, and the distance between the support pins 21 and 22 can be adjusted in the opening direction by the action of the spring 35. The wire mesh support 101 of the sensor 100 can be easily maintained in a tensioned state (with tension), and the sensor chip 102 can be stably supported.

  By the way, in the tip temperature measuring device 1 having the above-described configuration, since the wear of the sensor chip 102 is advanced by bringing the high-temperature tip into contact with the sensor chip 102 many times, the lifetime of the temperature sensor 100 is determined. Need to be exchanged. It has been found that the consumption of the sensor chip 102 in this case is proportional to temperature and time. Therefore, the control device built in the tip temperature measuring device 1 includes a life evaluation device having a configuration as shown in FIG.

  As shown in the block diagram of FIG. 4, this life evaluation apparatus detects a temperature sensor 201 that detects the temperature of an object to be measured, and when the temperature sensor 201 detects a temperature above a certain level (for example, 200 ° to 550 °). Based on both the timer (time measuring means) 207 for measuring the elapsed time during which the temperature is detected and the temperature detected by the temperature sensor 201 and the time measured by the time measuring means, the higher the temperature, the longer the time. The calculation unit 202 (evaluation value calculation means, integration) calculates an evaluation value that increases as the value of the value becomes longer and calculates the integrated value of the evaluation value every time the temperature sensor 201 detects a temperature (200 ° to 550 °) above a certain level. Means), a storage unit 203 (storage means) for updating and storing the calculated integrated value, and an alarm means for generating an alarm signal when the integrated value of the evaluation value exceeds a preset life value Included in the calculation unit 202), a display unit 206 for displaying an alarm, a reset unit 205 (reset means) for resetting the accumulated value stored in the storage unit 203 to zero, and a lifetime for inputting an arbitrary lifetime value as a lifetime value A value setting unit 204 (life value setting means).

  In this case, the measurement object corresponds to the sensor chip 102 in the temperature sensor 100 of the tip temperature measuring device 1 in particular, and the temperature sensor 201 is in particular the temperature sensor 100 in the tip temperature measuring device 1. It corresponds to the thermocouple 103. In the reset unit 205, the sensor reset switch 17 mainly plays a role, and in the lifetime value setting unit 204, the hold / mode switch 6 mainly plays a role. The display unit 206 corresponds to the display unit 14 of the tip temperature measuring device 1. The storage unit 23 includes a volatile first memory 208 and a nonvolatile second memory 209. The integrated value of the evaluation values is stored in the nonvolatile second memory 209. Necessary arithmetic expressions and maps are also stored in the nonvolatile second memory 209. The volatile first memory 208 provides a work area necessary for calculation and serves to temporarily store evaluation values and integrated values. In addition, here, the target for life evaluation is the temperature sensor 100 itself.

Next, the control flow of sensor life evaluation will be described with reference to the flowchart of FIG.
The sensor life evaluation program starts when the power switch is turned on. When starting, it is first determined in step S101 whether or not the integrated value of the life evaluation value has been reset. If YES, the integrated value is reset to zero in step S102. If NO, the process proceeds directly to step S103. In step S103, it is determined whether the setting of the life value has been changed. If YES, the life value is set and changed in step S104. If NO, the process proceeds directly to step S105.

  In step S105, the temperature is measured by the temperature sensor 201. Based on the detected temperature data, it is determined in step S107 whether or not the condition that the detected temperature is 200 ° to 550 ° is satisfied. If any of them is NO, the process returns to step S105, and steps S105 to 107 are performed. repeat. If both the determinations in steps S106 and 107 are YES, the process proceeds to step S108 where the elapsed time is measured. Next, in step S109, the current value m of the life evaluation value is calculated from both the temperature and time data. This calculation is performed using, for example, a map shown in Table 1 or a calculation expression registered in advance.

  The contents of Table 1 are derived from a life test and define the damage of the sensor chip 102. It is known that the damage to the sensor chip 102 increases in proportion to the temperature of the tip and the elapsed time that the tip is in contact with the sensor chip 102. The temperature is indicated in the vertical column and 1 in the horizontal column. The continuous use time of the trowel is taken. As can be seen from this table, in the vertical direction, it is found that there is a life change of 3.333 times per 50 ° C. temperature change (note that this magnification can be arbitrarily set). The horizontal direction is proportional to time.

The calculation is performed at 350 ° C. with 3 seconds as a reference (life evaluation value 1.00).
[Working time (seconds) / 3 seconds] × [(temperature difference from 350 ° C.) / 50 ° C.] × 3.333
The evaluation value m is calculated by continuously integrating the values calculated in (1).

  After calculating the evaluation value m in the current tip temperature measurement in step S109, in step S110, the evaluation value m is added to the integrated value M of the evaluation values integrated up to the previous time, and a new integrated value M is obtained. Update the calculation. Then, in the next step S111, it is determined whether or not the updated integrated value M exceeds the lifetime value. If the lifetime value is exceeded (YES), it is determined that the lifetime is reached, and an alarm signal is generated in step S112, for example, an alarm is sounded or an alarm is displayed.

  If the integrated value M does not exceed the lifetime value, the alarm step 112 is passed and the process proceeds to step S113. Here, it is confirmed whether or not one measurement has been completed. When one measurement is being continued, the processing from step S108 to step S113 is repeated. When one measurement is finished, the newly updated integrated value M is stored in the nonvolatile second memory 209 in step S114, and the process is finished.

  As described above, the evaluation value corresponding to the temperature history is calculated using the temperature and time as parameters, and the alarm signal is generated when the integrated value of the evaluation value exceeds the lifetime value. Can easily and reasonably be determined. In addition, since the life value can be arbitrarily set in advance by the life value setting unit 204, the replacement time can be freely selected according to the conditions of the user, the material used, and the like. Further, by resetting the integrated value M stored in the storage unit 203 by the reset unit 205, the lifetime of the temperature sensor 100 can be determined many times each time it is replaced.

In addition, although the case where this invention was used for the lifetime determination of the temperature sensor 100 of the tip temperature measuring apparatus 1 was demonstrated in the said embodiment, it can also be used for lifetime evaluation other than that. For example, it can be used to determine the life of the trowel itself.
In the above embodiment, the formula for obtaining the evaluation value is determined by so-called empirical rules obtained as a result of various experiments, but the evaluation value may be obtained by a preset map instead of the formula.

DESCRIPTION OF SYMBOLS 1 Tip temperature measuring apparatus 100 Temperature sensor 201 Temperature sensor 202 Calculation part (Evaluation value calculation means, integration means, alarm means)
203 memory | storage part (memory | storage means)
204 Life setting unit (life value setting means)
205 Reset unit (reset means)
207 Timer (time measuring means)
H Soldering iron

Claims (3)

A temperature sensor for detecting the temperature of the measurement object;
A time measuring means for measuring an elapsed time when the temperature sensor detects a temperature above a certain level, and detecting the temperature;
Based on both data detected by the temperature sensor and time measured by the time measuring means, evaluation value calculating means for calculating an evaluation value that increases as the temperature increases and the time increases,
Integrating means for calculating an integrated value of the evaluation values each time the temperature sensor detects a temperature above a certain level;
Storage means for updating and storing the integrated value calculated by the integrating means;
Alarm means for generating an alarm signal when the integrated value of the evaluation values exceeds a preset life value;
A life evaluation apparatus based on a temperature history.   2. The temperature history according to claim 1, further comprising: reset means for resetting the accumulated value stored in the storage means to zero; and life value setting means for inputting an arbitrary life value as the life value. Life evaluation device by. The life evaluation apparatus according to the temperature history according to claim 1 or 2,
As the temperature sensor, a temperature sensor capable of detecting the temperature of the tip by contacting the tip is provided,
A tip temperature measuring device characterized in that an object for life evaluation is the temperature sensor itself.

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