JP2010047800A - Heating furnace and heating apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heating furnace and a heating apparatus which continuously and stably remove residual strain of an SMA (Shape Memory Alloy) wire. <P>SOLUTION: The heating furnace includes: a heating portion in which a first passage for heating a part of the wire to an austenite transformation finish temperature or higher is formed; and two guide portions in each of which a second passage for passing the wire therethrough is formed, the second passages being arranged integrally with the heating portion so as to communicate with both end parts of the first passage, respectively. In the heating furnace, the guide portions are constituted in such a manner that each of temperature at the openings in two guide portions becomes a martensite transformation finish temperature or lower under tension. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a heating furnace and a heating apparatus for heating a wire made of a shape memory alloy.

  2. Description of the Related Art There is known a driving device that drives an object to be driven using expansion and contraction of a wire or foil made of a shape memory alloy (Shape Memory Alloy, hereinafter referred to as SMA). When manufacturing such a drive device, the initial state in which the SMA is installed is inspected. However, due to variations in tension adjustment during installation, fluctuations in tension resulting from the SMA installation state, etc. There is a problem that the initial position of the object varies.

  In order to adjust the initial position of the driving object to such a problem, a driving device provided with an adjusting mechanism has been proposed (for example, see Patent Document 1).

  However, even if the adjustment proposed in Patent Document 1 is performed, there is a problem in that the initial position of the driven object is shifted due to the SMA stress fluctuating during the first expansion and contraction driving due to the characteristics of the SMA.

  The characteristics of SMA will be described with reference to FIG. FIG. 17 is a graph showing an example of stress-strain characteristics of SMA. The horizontal axis in FIG. 17 is strain, and the vertical axis is stress.

  For example, after applying stress from point 0 to point A in FIG. 17, when the stress is removed, point A ′ is reached as shown by the arrow in the figure. The strain at point A 'is the residual strain. When stress is applied to the SMA again from this state, the strain of the SMA increases from the A ′ point to the A point. Since the residual strain disappears once the SMA is heated and austenite transformed, the relationship between stress and strain becomes the relationship indicated by 0A on the graph again.

  In general, in a driving apparatus using a wire made of SMA (hereinafter referred to as SMA wire), a method of fixing the SMA wire to two metal terminals is employed. Even if the stress applied to the SMA wire when it is installed between the terminals is constant, a stress difference results as a result of the presence or absence of residual strain. For example, the design target value of the stress applied to the SMA wire when it is installed between the terminals is b1. When the stress b1 is applied to the SMA wire having no residual strain, it reaches the point B on the straight line from the 0 point in the figure, whereas the SMA having the residual strain remaining at the point A ′ as described above, for example. When b1 stress is applied to the wire, it reaches the point C ′ on the straight line from the point A ′ in the figure.

  After the SMA wire is fixed between the terminals of the driving device with the b1 stress applied to the SMA wire in which the residual strain remains in this way, the residual strain is eliminated by heating the SMA wire to cause austenite transformation. When the residual strain is eliminated, the length of the SMA wire is balanced at the point C on the straight line 0A where the strain becomes c2. That is, when the residual strain is eliminated by heating the SMA wire, the stress becomes c1, and a stress difference b1-c1 with the stress b1 when the SMA wire is installed is generated. However, it is difficult to measure the amount of residual strain of the SMA wire in advance, and it is not possible to select SMA wires having no residual strain or to correct the stress difference according to the amount of residual strain.

In order to solve such a problem, after an SMA wire is installed on the object to be installed, the supplied SMA wire is energized and heated to the austenite temperature range, and then fixed to the driving device while applying a predetermined tensile stress. Has proposed a manufacturing method that eliminates stress fluctuations during installation of SMA wires (see, for example, Patent Document 2).
JP-A-10-160997 JP 2007-162612 A

  However, in the manufacturing method disclosed in Patent Document 2, the process of laying the SMA wire and the process of heating are performed in the same environment, so it is difficult to manage the environment around the SMA wire. Therefore, there is a possibility that heating to the austenite temperature range cannot be performed. In addition, after SMA wire having a predetermined length is installed for each part, heating, cooling, and tension adjustment are performed, so that there is a face that is not suitable for continuous production.

  This invention is made | formed in view of the said subject, Comprising: It aims at providing the heating furnace and heating apparatus which can remove a residual distortion SMA wire continuously and stably.

  The object of the present invention can be achieved by the following constitution.

1. A wire made of a shape memory alloy to which a certain tension is applied is disposed so as to pass through, placed in an environment below the martensite transformation end temperature of the wire, and the wire passing through is heated to remove residual strain. A heating furnace,
A heating part in which a first passage for heating a part of the wire to an austenite transformation end temperature or higher is formed;
A second passage is formed through which the wire passes and communicates with both ends of the first passage, and two guide portions provided so as to protrude from the wall surface of the heating portion;
With
The guide portion is
A heating furnace characterized in that the temperature at the opening of the two guide portions is equal to or lower than the martensite transformation end temperature in the tension.

  2. 2. The heating furnace according to claim 1, wherein an internal space of the heating furnace including the first passage and the second passage is opened to an external environment by only two openings.

  3. 3. The heating furnace according to 1 or 2, wherein the guide portion is cylindrical.

4). The cross-sectional area of the cross section perpendicular to the wire passing direction of the guide portion is:
Less than the cross-sectional area of the cross section perpendicular to the wire passing direction of the heating unit,
4. The heating furnace according to any one of 1 to 3, wherein the guide portion is installed so that a passage direction of the wire is horizontal.

5). The heating furnace according to any one of 1 to 4,
Heating means for heating the heating section of the heating furnace;
A heating part temperature sensor for detecting the temperature of the heating part;
A control circuit for controlling the heating means based on the temperature detected by the heating unit temperature sensor;
A heating device comprising:

6). A heating furnace that is arranged so that a wire made of a shape memory alloy to which a certain tension is applied passes, and heats the passing wire to remove residual strain,
A heating part in which a first passage for heating a part of the wire to an austenite transformation end temperature or higher is formed;
A second passage is formed through which the wire passes and communicates with both ends of the first passage, and two guide portions provided so as to protrude from the wall surface of the heating portion;
Cooling means for cooling the guide portion;
A heating furnace comprising:

7). The cooling means is
The guide part is formed of a material having a higher thermal conductivity than the material forming the guide part, the guide part is connected to a fixed part having a larger heat capacity than the guide part, and the guide part is cooled by heat conduction. The heating furnace as described in 6 above, wherein:

8). The cooling means is
The heating furnace as described in 6 above, wherein the heating furnace is an air blowing means for blowing air to the guide portion.

9. The cooling means is
The heating furnace as described in 6 above, wherein the heating furnace is a radiator attached to the guide portion.

10. The heating furnace according to any one of 6 to 9,
Heating means for heating the heating section of the heating furnace;
A heating part temperature sensor for detecting the temperature of the heating part;
A control circuit for controlling the heating means based on the temperature detected by the heating unit temperature sensor;
A heating device comprising:

11. A guide part temperature sensor for detecting the temperature of the guide part;
The control circuit includes:
11. The heating apparatus according to 10, wherein the cooling unit is controlled based on a temperature detected by the guide part temperature sensor.

  According to the present invention, the heating section in which the first passage for heating a part of the wire to the austenite transformation end temperature or higher is formed in the heating furnace, the second passage through which the wire passes, and the second passage is the first passage. Two guide portions formed integrally with the heating portion so as to communicate with both ends of one passage are provided, and the opening temperature of the two guide portions is configured to be equal to or lower than the martensite transformation end temperature at a predetermined tension. is doing. Therefore, it is possible to provide a heating furnace and a heating device that can remove residual strain continuously and stably from the SMA wire.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a block diagram showing an example of a manufacturing system 1 using the heating device 20 of the present invention, FIG. 2 is a graph showing an example of temperature-strain characteristics of the SMA wire 2, and FIG. 3 is a first embodiment of the present invention. It is sectional drawing explaining the 1st example of the heating apparatus 20 of a form.

  First, the entire manufacturing system 1 will be described with reference to FIG.

  The manufacturing system 1 includes a stock control unit 10, a heating device 20, a fastening unit 30, a transport unit 31, a control unit 14, and the like.

  One end of the SMA wire 2 wound around the reel 11 is fixed to a construction object 70 (not shown in FIG. 1) mounted on the transport pallet 32 of the transport fastening unit 30, so that the transport pallet 32 moves. Accordingly, it is pulled out from the reel 11 in the right direction on the paper surface. Between the reel 11 and the transport pallet 32, the SMA wire 2 changes direction along the guide rollers 14a, 13, 14b and enters the heating device 20, and after leaving the heating device 20, changes direction with the guide roller 14c. It is connected to the object 70. For example, a NiTi-based material is used for the SMA wire 2.

  The stock control unit 10 includes a reel 11 around which the SMA wire 2 is wound, a motor 15 in which a rotation shaft is directly connected to the rotation center of the reel 11, and guide rollers 14 a and 13 on which the SMA wire 2 pulled out from the reel 11 is hung. 14b, a tension sensor 12 for detecting the tension of the SMA wire 2 passing through the guide roller 13, and the like.

  The control unit 14 includes a CPU (Central Processing Unit) (not shown), a RAM (Random Access Memory), a ROM (Read Only Memory), and the like, and a program stored in the ROM, which is a nonvolatile storage unit, is stored in the RAM. Reading and centrally controlling each part of the manufacturing system 1 according to the program.

  The control unit 14 controls the rotation of the motor 15 according to the tension of the SMA wire 2 hung on the guide roller 13 detected by the tension sensor 12. When the tension exceeds the target value, the control unit 14 rotates the motor 15 in the direction of feeding the SMA wire 2 according to the difference. When the tension is below the target value, the control unit 14 rotates the motor 15 in the reverse direction according to the difference. Control to achieve the target value.

  FIG. 2 is a graph showing an example of temperature-strain characteristics of the SMA wire 2. The characteristics of the SMA wire 2 used in this embodiment will be described with reference to FIG.

  The horizontal axis in FIG. 2 is temperature, the vertical axis is strain, and the direction indicated by the arrow is the shrinking direction.

  In the figure, AS is the austenite transformation start temperature, AF is the austenite transformation end temperature, MS is the martensite transformation start temperature, MF is the martensite transformation end temperature, Tr is room temperature, and Tm is the memory temperature. It is assumed that the SMA wire 2 is given a certain tension and stretched by a predetermined amount at room temperature. When the SMA wire 2 is heated and the temperature becomes equal to or higher than the austenite transformation start temperature, it rapidly contracts as shown in FIG. When the temperature reaches the austenite transformation end temperature or higher, the SMA wire 2 is transformed into the austenite phase, and the residual strain is removed.

  Next, when the temperature of the SMA wire 2 is set to be equal to or lower than the martensite transformation start temperature, the SMA wire 2 is rapidly stretched as shown in FIG. The SMA wire 2 transforms to the martensite phase when the temperature is below the martensitic transformation end temperature.

  As the wire diameter of the SMA wire 2 is thinner, the heat capacity is smaller, so that the temperature rises and falls with the same energy is faster, and the responsiveness is improved. Further, a material having an austenite transformation start temperature and a martensite transformation end temperature of, for example, 60 ° C. or more is used for the SMA wire 2 so that the installation target 70 on which the SMA wire 2 is installed operates even in a high temperature environment. In such materials, the austenite transformation end temperature is about 100 ° C to 200 ° C.

  Next, the heating device 20 and the heating furnace 230 according to the first embodiment of the present invention will be described with reference to FIGS.

  FIG. 3 is a first example of the heating device 20 according to the first embodiment. FIG. 3A is a side view of the heating device 20 of the first example of the first embodiment, and FIG. 3B is a cross-sectional view of the A-A ′ surface of the heating device 20.

  The heating device 20 includes a heating furnace 230, a heater 21, a heating unit temperature sensor 22, a control circuit 23, and the like.

  The heating furnace 230 includes a heating unit 24 that is heated by the heater 121 and thin-walled cylindrical guide portions 25 a and 25 b that protrude from the wall surface of the heating unit 24. The heating section 24 is formed with a first passage 221 that heats a part of the passing SMA wire 2 to the austenite transformation end temperature or higher. As shown in FIG. 3, the guide portions 25a and 25b are provided so as to protrude from the wall surface of the heating portion 24, and second passages 220a and 220b communicating with both ends of the first passage 221 are formed.

  In this example, the diameters φ of the first passage 221 and the second passages 220a and 220b are the same, and holes having the same thickness penetrate from the guide portion 25a to the guide portion 25b. The first passage 22 and the second passages 220a and 220b are linear as shown in FIG. 3, and the internal space of the heating furnace 230 composed of the first passage 22 and the second passages 220a and 220b has openings 29a and 29b. Only open to the atmosphere side. In the present embodiment, the SMA wire 2 passes through the second passage 220a, the first passage 221, and the second passage 220b from the opening 29a toward the opening 29b.

  The heating unit 24 is preferably configured so that the ratio of heat capacity / surface area is increased, and the guide units 25a and 25b are preferably configured so that the ratio of heat capacity / surface area is decreased.

  In the embodiment described below, the heating furnace 230 is installed such that the longitudinal direction of the second passages 220a and 220b is horizontal. Moreover, the heating apparatus 20 shall be installed in the atmosphere adjusted to temperature below the martensitic transformation completion temperature, for example, 25 degreeC.

  The heating part temperature sensor 22 is arranged to detect the temperature of the first passage 221 at a position facing the heater 121 in the vicinity of the heating center 235 located at the center of the heating part 24 as shown in FIG. ing. The control circuit 23 controls the heater 22 so that the temperature of the heating center 235 becomes equal to or higher than the austenite transformation end temperature based on the temperature information detected by the heating unit temperature sensor 22. The heater 121 is a heating means of the present invention.

  In the figure, φ is the diameter of the opening 29a and the opening 29b of the passage 220, and x1 is the distance from the opening 29a on the inlet side of the second passage 220a to the heating center 235 where the SMA wire 2 is heated to the austenite transformation finish temperature or higher. It is. x2 is the distance from the heating center 235 to the opening 29b on the outlet side of the second passage 220b. It is desirable to make φ as small as possible and make x1 and x2 as large as possible so that air does not flow into the second passages 220a and 220b from the openings 29a and 29b. When at least φ <x1 and φ <x2, it is possible to prevent air from flowing in.

  The SMA wire 2 travels from the second passage 220a along the first passage 221 and is heated above the austenite transformation end temperature in the vicinity of the heating center 235. As a result, the portion of the SMA wire 2 heated to the austenite transformation end temperature or more is transformed into an austenite phase, and residual strain is removed.

  In the heating furnace 230 of the present invention, the SMA wire 2 can be reliably heated to the austenite temperature range without being affected by the environmental temperature and wind.

  On the other hand, the heating unit 24 heated by the heater 121 becomes a high temperature, and the air heated by the heating unit 24 generates a rising airflow that rises in the vertical direction around the heating furnace 230. A part of the air heated on the bottom surface of the heating unit 24 moves along the bottoms of the guide portions 25a and 25b and approaches the openings 29a and 29b. However, since the guide portions 25a and 25b have at least the opening 29a and the vicinity of the opening 29b are thinner than the heating portion 24, the warmed air passes through the guide portions 25a and 25b before reaching the openings 29a and 29b. It rises and does not affect the temperature of the openings 29a and 29b. Further, since the air heated on the side surface of the heating unit 24 rises as it is, it does not affect the temperatures of the openings 29a and 29b.

  By providing the guide portions 25a and 25b in this manner, the temperatures of the openings 29a and 29b can be made lower than the martensite transformation end temperature without being affected by the air heated by the heating unit 24. Therefore, the SMA wire 2 is not contracted by the air heated by the heating unit 24 in the vicinity of the opening 29b, and the tension does not fluctuate rapidly.

  The portion of the SMA wire 2 heated near the austenite transformation end temperature in the vicinity of the heating center 235 proceeds along the second passage 220b and exits from the heating furnace 23 through the opening 29b. The temperature of the opening 29b is equal to or lower than the martensite transformation end temperature, and the portion of the SMA wire 2 that has been heated above the austenite transformation end temperature at the heating center 235 and from which residual strain has been removed transforms into the martensite phase when leaving the opening 29b. .

  In the heating device 20 of the present invention, since the region for heating the SMA wire 2 is small as described above, it is possible to reduce the power consumption and the size of the manufacturing system, and there is almost no influence of the heat on the installation target object 70. Further, in the method of heating after the SMA wire 2 is installed on the installation object 70, the temperature distribution may be uneven, and there is a possibility that residual distortion is not sufficiently heated, but in the present invention, the residual distortion is reliably removed. it can.

  FIG. 4 is a cross-sectional view of a second example of the heating device 20 of the first embodiment.

  The difference between the first example of FIG. 3 and the second example is that the liquid 204 is used to heat the SMA wire 2. As the liquid 204, various liquids such as water and fluorinate can be used. However, if the liquid boils, there is a possibility that the vapor will be ejected from the opening through the passage 220 and the SMA wire 2 may be contracted. Those that do not are preferred.

  The heating device 20 of the second example includes a heating furnace 230, a heater 21, a heating unit temperature sensor 22, a control circuit 23, a ventilator 202, and the like.

  The ventilator 202 is provided to suppress an increase in pressure due to steam generated when a liquid (for example, water) having a boiling point close to the austenite transformation end temperature is used. By providing the ventilator 202 in this way, it is possible to reduce only the atmospheric pressure while preventing the inflow of outside air.

  The heating section 24 of this example is provided with a first passage 221 larger than the second passages 220a and 220b of the guide portions 25a and 25b, and is filled with the liquid 204. The heating unit temperature sensor 22 is arranged to detect the temperature of the liquid 204 as shown in FIG. The control circuit 23 controls the heater 22 so that the temperature of the liquid 204 becomes equal to or higher than the austenite transformation end temperature based on the temperature information detected by the heating unit temperature sensor 22.

  The second passages 220a and 220b are linear as shown in FIG. 4, and only the openings 29a and 29b are opened to the atmosphere side in the internal space of the heating furnace 230 including the first passage 221. A part of the pulley 205 b is immersed in the liquid 204.

  As in the first example, the diameter of the openings 29a and 29b is smaller than the distance from the openings 29a and 29b to the heating center 235 so that air does not flow into the second passages 220a and 220b. The temperature of the center 235 does not fluctuate.

  The SMA wire 2 that has passed through the second passage 220a travels along the pulleys 205a, 205b, and 205c, and is partially immersed in the liquid 204 and heated above the austenite transformation temperature. As a result, the portion of the SMA wire 2 heated to the austenite transformation end temperature or more is transformed into an austenite phase, and residual strain is removed.

  Due to the effect of the guide portions 25a and 25b, the temperature of the opening 29b is equal to or lower than the martensite transformation end temperature, and the portion of the SMA wire 2 from which the residual strain has been removed transforms into the martensite phase when leaving the opening 29b.

  FIG. 5 is a cross-sectional view of a third example of the heating device 20 of the first embodiment.

  The difference between the second example of FIG. 4 and the third example is that the pulley 205b is heated and the SMA wire 2 that contacts the pulley 205b is heated. If it does in this way, compared with the case where the SMA wire 2 is heated via air or a liquid, the energy which a heating requires can be decreased.

  The heating unit temperature sensor 22 is arranged not to detect the temperature of the pulley 205b but to detect the temperature of the first passage 221 as shown in FIG. The control circuit 23 controls the heater 22 so that the temperature of the pulley 205b becomes equal to or higher than the austenite transformation end temperature based on the temperature information detected by the heating unit temperature sensor 22 and the temperature correction information measured in advance.

  The configurations and effects of the guide portions 25a and 25b are the same as those in the second example, and a description thereof will be omitted.

  FIG. 6 is a fourth example of the heating device 20 according to the first embodiment. FIG. 6 is a sectional view of the heating device 20.

  The difference between the third example of FIG. 5 and the fourth example is that the SMA wire 2 is energized and heated. In this way, the energy required for heating can be further reduced than in the third example.

  The pulley 205b is connected to a constant current circuit 270, and the pulley 205a and the pulley 205c are grounded. When the control circuit 23 controls the constant current circuit 270 and the constant current circuit 270 supplies a constant current to the pulley 205b, the SMA wire 2 that contacts the pulley 205a and the pulley 205c from the portion of the SMA wire 2 that contacts the pulley 205b, respectively. A constant current flows through this part and generates heat above the austenite transformation end temperature. The constant current circuit 270 is the heating means of the present invention.

  The configurations and effects of the guide portions 25a and 25b are the same as those in the third example, and a description thereof will be omitted.

  Next, the heating furnace 230 of 2nd Embodiment of this invention is demonstrated. A feature of the heating furnace 230 of the second embodiment is that a cooling means for cooling the guide portions 25a and 25b is provided. The heating furnace 230 of the second embodiment will be described with reference to FIGS.

  FIG. 7 is an explanatory diagram for describing a first example of the heating furnace 230 of the second embodiment. FIG. 7B is a plan view of the heating furnace 230 viewed from the vertical direction, and FIG. 7A is a side view of the heating furnace 230. 7C is a cross-sectional view taken along the line CC ′ in FIG. 7B, FIG. 7D is a cross-sectional view taken along the line DD ′ in FIG. 7A, and FIG. ) Is a cross-sectional view taken along the line EE ′ in FIG. 7B, and FIG. 7F is a cross-sectional view taken along the line FF ′ in FIG. 7B.

  In addition, the same number is attached | subjected to the same component as the component demonstrated so far, and description is abbreviate | omitted.

  In this embodiment, the heater 21 is embedded in the heating unit 24 so that the heater 21 can be heated close to the first passage 221 and efficiently. As in the first embodiment, only the guide portions 25a and 25b are in contact with the heating portion 24, and the heat is not conducted to the portions other than the guide portions 25a and 25b.

  On the other hand, in this embodiment, the 2nd guide part 26 with large heat capacity is attached to the guide parts 25a and 25b, and the heat dissipation effect is heightened. Heat is conducted from the guide portion 25 to the second guide portion 26 and further to the leg portion 27 attached to the second guide portion 26 as indicated by an arrow in FIG. The leg 27 is fixed to a fixed base 240 having a large heat capacity, and the heat conducted to the leg 27 is radiated to the fixed base 240. The 2nd guide part 26 and the leg part 27 are the cooling means of this invention.

  Since the heating unit 24 is heated by the heater 21 and is at a high temperature, the air around the heating unit 24 is warmed to generate an upward airflow in the vertical direction as indicated by an arrow shown in FIG. In the present embodiment, the second guide portion 26 is configured to surround the heating portion 24, and since the periphery of the heating portion 24 is almost open, the heated air as indicated by the arrows shown in FIG. Rises in the vertical direction along the side surface of the heating unit 24 and does not affect the temperature of the openings 29a and 29b.

  Further, since the cross-sectional area S of the guide portions 25a and 25b is smaller than the cross-sectional area P of the heating portion 24, the air heated by the guide portions 25a and 25b is also guided as shown by the arrows in FIG. It rises in the vertical direction along the side surfaces of the portions 25a and 25b, and does not affect the temperature of the openings 29a and 29b.

  As another method, if the portion other than the central portion of the heating unit 24 is made of a material having low thermal conductivity, the degree of freedom in design can be increased.

  FIG. 8 shows a second example of the heating furnace 230 of the second embodiment.

  8A is a side view of the heating furnace 230, and FIG. 8B is a front view of the heating furnace 230. FIG. 8C is a side view of the heating furnace 230 for explaining the heat conduction path, and FIG. 8D is a cross-sectional view of the heating furnace 230 for explaining the heat conduction path.

  As shown in FIG. 8, leg portions 27 are attached to the guide portions 25 a and 25 b, and the leg portions 27 are fixed to the fixing base 240. The heat generated in the heater 21 is conducted from the heating part 24 to the guide parts 25a and 25b and the leg part 27 as shown by the arrow in FIG. If the heat conductivity of the leg portion 27 is configured to be higher than that of the guide portion 25, most of the heat is dissipated from the leg portion 27 as indicated by the arrow in FIG. 8D, and the openings 29a, 29b of the guide portions 25a, 25b. It does not conduct nearby.

  FIG. 9 shows a third example of the heating furnace 230 of the second embodiment.

  FIG. 9A is a side view of the heating furnace 230, and FIG. 9B is a front sectional view of the heating furnace 230.

  As shown in FIG. 9, a radiator 28 is attached to the guide portions 25 a and 25 b, and the radiator 28 is fixed to a fixed base 240. The inside of the radiator 28 has a tubular shape so that the refrigerant passes therethrough, and when the refrigerant is injected into the radiator 28 from the direction of arrow I in FIG. For example, water is used as the refrigerant. If comprised in this way, heat dissipation efficiency can be made the highest and the heating apparatus 20 can be reduced in size.

  FIG. 10 shows a fourth example of the heating furnace 230 of the second embodiment.

  FIG. 10A is a side view of the heating furnace 230, and FIG. 10B is a front sectional view of the heating furnace 230.

  As shown in FIG. 10, the air nozzle 200 and the suction nozzle 201 are attached to the guide portions 25 a and 25 b at positions facing the air nozzle 200. Air is ejected from the air nozzle 200 toward the guide portions 25a and 25b, and the suction nozzle 201 is configured to suck air and create a flow of air around the guide portions 25a and 25b to dissipate heat by air cooling. Note that the suction nozzle 201 is not necessarily provided unless dust is a problem. The air nozzle 200 is a blowing means of the present invention.

  7 to 10, the heating unit temperature sensor 22 is not shown for the sake of simplicity, but it may be provided at a position facing the heater 21 as in FIG.

  Next, the heating apparatus 20 of 3rd Embodiment of this invention is demonstrated. FIG. 11 shows a heating device 20 according to the third embodiment. The difference between the heating device 20 of the third embodiment and the heating device 20 of the second embodiment is that a guide part temperature sensor 242 for detecting the temperature of the guide part 25a is provided and the temperature of the opening 29 is controlled to be constant. .

  In this case, the air nozzle 200 and the suction nozzle 201 may be operated as necessary, so that energy efficiency is good. Moreover, it can respond also to the change of the environmental temperature in which the heating apparatus 20 is installed.

  This embodiment can also be applied to the case of cooling with a liquid as in the second example of the heating furnace 230 of the third embodiment.

  In this embodiment, the guide part temperature sensor 242 is provided only on the opening 29a side. However, when the guide part 25a and the guide part 25b are not symmetrical with respect to the heating center 235, the guide part temperature sensor is also provided on the opening 29b side. It is necessary to control each temperature independently.

  In the temperature control of the heating center 235, the target temperature is determined, and since the surroundings are configured with a large heat capacity, the temperature change is small, and the control is simple and can be controlled by simple ON / OFF control. On the other hand, although the guide portion 25a and the guide portion 25b are configured to have a small heat capacity, a time delay occurs in heat dissipation. For this reason, it is necessary to set the temperature control threshold value below the martensitic transformation end temperature.

  Next, an example of the conveyance part 31 used for the manufacturing system 1 using the heating apparatus 20 of this invention is demonstrated using FIG. FIG. 12 is a plan view of the transport unit 31.

  FIG. 12 illustrates an example in which two transport pallets 32 a and 32 b are mounted on the transport unit 31. The conveyance pallets 32a and 32b have the same configuration, and each component is distinguished by adding a and b as necessary.

  As will be described in detail later, the movement direction of the conveyance pallet 32 is in the order of arrows F1, F2, and F3. After the conveyance pallet 32 is inserted to a predetermined position in the F1 direction, it is pushed in the F2 direction by the conveyance member 35. It moves to the right side of the page and is discharged in the F3 direction. The transport member 35 is movable in the direction of arrow F2 or the reverse direction and is driven by the transport mechanism 36.

  A construction object 70 (not shown in FIG. 12) is mounted on the work accommodating portion 34 provided in the rotating portion 33 of the transport pallet 32. The urethane roller 37 is connected to a driving source (not shown) that rotates according to a command from the control unit 14, and contacts the rotating unit 33b to rotate the rotating unit 33b as shown in FIG. As will be described later, an SMA wire is installed on the installation object 70 mounted on the rotating unit 33b as the rotating unit 33b rotates.

  FIG. 13 is a plan view of an example of the installation target object 70, and FIG. 14 is a side view of an example of the installation target object 70.

  First, the lens unit shown in FIGS. 13 and 14 will be described as an example of the installation object 70.

  The construction object 70 shown in FIGS. 13 and 14 is configured to drive the lens driving frame 72 by a lens driving mechanism including the lever 76, the SMA wire 2, the terminal 74, and the terminal 75. A lens 71 is incorporated in the lens driving frame 72. Note that the cover 80, the bias spring 79, and the parallel leaf spring 81 shown in FIG. 14 are not shown in FIG. 13 for the sake of simplicity.

  14A is a side view of the lens drive frame 72 in the initial position, and FIG. 14B is a side view of the lens drive frame 72 extended in the direction of the arrow P2.

  As shown in FIG. 13, the tip portion of the lever 76 divided into two U-shapes is in contact with the projection 82 and the projection 83 of the lens drive frame 72. As shown in FIG. 14, the lever 76 can be rotated in the direction of the arrow P1 in FIG. 14B or in the opposite direction with a hinge portion 78 provided on the base portion 73 as a fulcrum, as shown in FIG. 14B. When the SMA wire 2 contracts in the direction of the arrow P1, the tip portion of the lever 76 divided into two is configured to push up the protrusion 82 and the protrusion 83 in the direction of the arrow P2.

  The lens drive frame 72 is held in the vertical direction in FIG. 14 by a parallel leaf spring 81 so as to advance straight in the arrow P2 direction or in the reverse direction, and is biased by the bias spring 79 in the direction opposite to the arrow P2. As shown in FIG. 13, the SMA wire 2 has a central portion hooked by a hook portion 77 of a lever 76 and both ends fixed to a terminal 74 and a terminal 75.

  A procedure for driving the lens driving frame 72 will be described.

  When a voltage is applied between the terminals 74 and 75 and a current is applied to the SMA wire 2 to heat it, the SMA wire 2 undergoes austenite transformation and contracts, and the lever 76 rotates in the direction of the arrow P1 with the hinge portion 78 as the center of rotation. Move. Then, the tip portion of the lever 76 divided into two pushes up the protrusion 82 and the protrusion 83 in the direction of the arrow P2, and moves the lens drive frame 72 in the direction of the arrow P2 as shown in FIG.

  When the flow of current to the SMA wire 2 is stopped, the SMA wire 2 is naturally cooled and transformed into a martensite phase and extends in the direction opposite to the arrow P1, and the lens driving frame 72 returns to the initial position.

  FIG. 15 is a flowchart illustrating a procedure in which the manufacturing system 1 lays and fixes the SMA wire to the installation target 70. FIG. 16 illustrates the operation of the transport unit 31 for each procedure of installing and fixing the SMA wire to the installation target. It is explanatory drawing demonstrated.

  An example of a procedure for installing the SMA wire on the installation object 70 by the manufacturing system 1 will be described in the order of the flowchart of FIG. 15 with reference to the explanatory diagram of FIG. Note that the explanatory diagram of FIG. 16 is a simplified plan view of the transport unit 31 of FIG. 12 and illustrates only the portions necessary for the description in order to explain the movement of the construction object 70 mounted on the rotating unit 33. .

  In the description of the flowchart below, the construction object 70b will be described from the state where it is mounted on the rotating portion 33b of the transport pallet 32b as shown in FIG.

  One end of the SMA wire 2 drawn out from the reel 11 is fixed to the terminal 74b in the construction object 70b in FIG. The SMA wire 2 passes through the heating device 20 of the present invention, and after the SMA wire 2 is heated to the austenite transformation end temperature or higher, it is cooled to the martensite phase and supplied to the transport unit 31. Therefore, residual strain is removed from the SMA wire 2 supplied to the conveyance unit 31 in the heating and cooling process performed by the heating device 20.

  S1: A step of moving the transport pallet 32b straight in the direction of the arrow F2.

  The control unit 14 instructs the transport mechanism 36 to move the transport pallet 32b from the position shown in FIG. 16A to the position shown in FIG. In this step, the control unit 14 sets the tension control target value to bx less than the stress target value b1 of the SMA wire 2 after being installed on the installation object 70, and the motor according to the tension value detected by the tension sensor 12. 15 is controlled.

  In this step, the conveyance pallet 32b is moved straight in the direction of the arrow F2 and the SMA wire 2 corresponding to the movement distance is drawn from the reel 11, so that the load fluctuation is large and it is difficult to control the movement speed of the conveyance pallet 32b to be constant. Therefore, although the tension of the SMA wire 2 also varies from the control target value, the control target value of the SMA wire 2 is lower than the stress target value b1 so as not to exceed the stress target value b1 even if the tension of the SMA wire 2 varies. Set to bx. Thus, by setting the control target value of the tension of the SMA wire 2 lower than b1, it is possible to prevent the residual strain from occurring due to the tension of the SMA wire 2 exceeding b1 due to some error factor. It should be noted that bx is preferably sufficiently low with respect to b1.

  S2: A step of setting the tension control target value to b1.

  The control unit 14 sets the control target value for controlling the tension of the SMA wire 2 to the stress target value b1 of the SMA wire 2 after being installed on the installation target 70, and the motor according to the tension value detected by the tension sensor 12. 15 is controlled. Prior to installing the SMA wire 2 in the installation process of steps S3 and S4, the control unit 14 sets the tension control target value to b1, so that the tension of the installed SMA wire 2 becomes the stress target value b1. Control.

  S3: This is a step of rotating the rotating portion 33b of the transport pallet 32b.

  The controller 14 instructs the drive source of the urethane roller 37 to rotate the urethane roller 37 counterclockwise as shown in FIG. The urethane roller 37 rotates the rotating portion 33b in pressure contact in the clockwise direction. In the figure, O is the rotation center of the rotating portion 33b, and the hook portion 77 of the mounted object 70b is on the rotation axis. By rotating the rotating portion 33b in the clockwise direction, the SMA wire 2 is installed on the hook portion 77 and the terminal 75b of the lever 76b. The control unit 14 stops the driving of the urethane roller 37 when the rotating unit 33b is rotated by a predetermined angle to the position where the terminal 75b is installed.

  The length of the SMA wire 2 pulled out from the reel 11 in this step is short, and it is easy for the control unit 14 to control the tension of the SMA wire 2 so as not to exceed b1 even if a disturbance is applied to the SMA wire 2. The fluctuation range of is very small.

  S4: A step of crimping the terminal 75.

  In the previous step, the SMA wire 2 is in a groove provided in the terminal 75b. Further, the terminal 75b is located immediately below the punch 45b. The controller 14 rotates the motor 43b to lower the punch 45b until a predetermined load is applied to the terminal 75b, and then reversely rotates the motor 43b to raise the punch 45b. In this step, the SMA wire 2 is fixed to the terminal 75b, and the installation process is completed.

  S5: A step of setting the tension control target value to bx.

  The control unit 14 sets the tension control target value to bx less than b1, and controls the motor 15 according to the tension value detected by the tension sensor 12. After the installation process of steps S3 and S4 is completed, the control unit 14 sets the tension control target value to bx less than b1, and controls the tension of the SMA wire 2 to be bx. In the subsequent processes, the control target value of the tension of the SMA wire 2 is set lower than b1 as in step S1, so that it is possible to prevent the residual strain from occurring due to the tension of the SMA wire 2 exceeding b1 due to some error factor.

  S6: This is a step of supplying the transport pallet.

  The transport pallet 32a on which the new construction object 70a is mounted on the rotating unit 33a is moved in the direction of the arrow F1 by a driving means (not shown) and stopped at the position of FIG.

  S7: A step of crimping the terminal 74.

  In the previous step, the SMA wire 2 is in the groove of the terminal 74a. The terminal 74a is located directly under the punch 45a. The controller 14 rotates the motor 43b to lower the punch 45a until a predetermined load is applied to the terminal 74a, and then reversely rotates the motor 43a to raise the punch 45a. In this step, the SMA wire 2 is fixed to the terminal 74a of the new construction object 70a.

  S8: This is a step of cutting the SMA wire 2.

  The SMA wire 2 is located immediately below the cutting edge of the cutter 46. The control unit 14 instructs the cutter driving mechanism 47 to lower the cutter 46 toward the SMA wire 2 and cut the SMA wire 2.

  S9: A step of discharging the transport pallet.

  As shown in FIG. 7 (e), the conveying pallet 32 b on which the erected object 70 b has been mounted on the rotating part 33 b is moved in the direction of arrow F 3 by a driving means (not shown) and discharged from the conveying part 31. After the delivery pallet 32b is discharged, the delivery pallet 32a on which the new construction object 70a is mounted on the rotating portion 33a remains, and the process returns to step S1 to perform the construction process of the same procedure.

  This is the end of the description of the flowchart.

  As described above, in the manufacturing system 1 of this example, the SMA wire 2 is heated and cooled by the heating device 20 to remove residual strain, and the tension of the SMA wire 2 is controlled to the stress target value b1 of the SMA wire 2 after installation. While it is installed on the installation object 70. Even if the stress applied to the SMA wire 2 fluctuates during assembly, the stress-strain characteristic transitions within the range indicated by the oblique lines in FIG. There is no error.

  Therefore, it is possible to continuously produce the installation target object 70 in which the initial position of the drive target object is not shifted due to residual distortion in a short time.

  As described above, according to the present invention, it is possible to provide a heating furnace and a heating apparatus that can remove residual strain continuously and stably from an SMA wire.

It is a block diagram which shows an example of the manufacturing system 1 using the heating apparatus 20 of this invention. 4 is a graph showing an example of temperature-strain characteristics of the SMA wire 2. It is sectional drawing explaining the 1st example of the heating apparatus 20 of 1st Embodiment of this invention. It is sectional drawing explaining the 2nd example of the heating apparatus 20 of 1st Embodiment of this invention. It is sectional drawing explaining the 3rd example of the heating apparatus 20 of 1st Embodiment of this invention. It is sectional drawing explaining the 4th example of the heating apparatus 20 of 1st Embodiment of this invention. It is explanatory drawing for demonstrating the 1st example of the heating furnace 230 of 2nd Embodiment. It is explanatory drawing for demonstrating the 2nd example of the heating furnace 230 of 2nd Embodiment. It is explanatory drawing for demonstrating the 3rd example of the heating furnace 230 of 2nd Embodiment. It is explanatory drawing for demonstrating the 4th example of the heating furnace 230 of 2nd Embodiment. It is explanatory drawing for demonstrating the heating apparatus 20 of 3rd Embodiment. It is explanatory drawing explaining an example of the conveyance part 31 used for the manufacturing system 1 using the heating apparatus 20 of this invention. FIG. 5 is a plan view of an example of an installation object 70. It is a side view of an example of the construction target object. It is a flowchart explaining the procedure in which the manufacturing system 1 constructs and fixes an SMA wire to the construction object 70. It is explanatory drawing explaining operation | movement of the conveyance part 31 for every procedure which constructs and fixes an SMA wire to a construction object. It is a graph which shows the example of the stress-strain characteristic of SMA.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Manufacturing system 2 SMA wire 10 Stock control unit 11 Reel 12 Tension sensor 13 Guide roller 14 Guide roller 15 Motor 17 Control part 20 Heating device 21 Heater 22 Heating part temperature sensor 23 Control circuit 24 Heating part 25 Guide part 29 Opening 30 Fastening unit DESCRIPTION OF SYMBOLS 31 Conveying part 32 Conveying pallet 33 Rotating part 34 Work accommodating part 43 Motor 44 Load sensor 45 Punch 46 Cutter 70 Construction object 72 Lens drive frame 74, 75 Terminal 76 Lever 78 Hinge part 205 Pulley 220 Second passage 221 First passage 230 Heating furnace 235 Heating center 240 Fixed base 270 Constant current circuit

Claims (11)

A wire made of a shape memory alloy to which a certain tension is applied is disposed so as to pass through, placed in an environment below the martensite transformation end temperature of the wire, and the wire passing through is heated to remove residual strain. A heating furnace,
A heating part in which a first passage for heating a part of the wire to an austenite transformation end temperature or higher is formed;
A second passage is formed through which the wire passes and communicates with both ends of the first passage, and two guide portions provided so as to protrude from the wall surface of the heating portion;
With
The guide portion is
A heating furnace characterized in that the temperature at the opening of the two guide portions is equal to or lower than the martensite transformation end temperature in the tension. 2. The heating furnace according to claim 1, wherein an internal space of the heating furnace including the first passage and the second passage is opened to the external environment by only two of the openings. The heating furnace according to claim 1 or 2, wherein the guide portion is cylindrical. The cross-sectional area of the cross section perpendicular to the wire passing direction of the guide portion is:
Less than the cross-sectional area of the cross section perpendicular to the wire passing direction of the heating unit,
The heating furnace according to any one of claims 1 to 3, wherein the guide portion is installed so that a passage direction of the wire is horizontal. A heating furnace according to any one of claims 1 to 4,
Heating means for heating the heating section of the heating furnace;
A heating part temperature sensor for detecting the temperature of the heating part;
A control circuit for controlling the heating means based on the temperature detected by the heating unit temperature sensor;
A heating device comprising: A heating furnace that is arranged so that a wire made of a shape memory alloy to which a certain tension is applied passes, and heats the passing wire to remove residual strain,
A heating part in which a first passage for heating a part of the wire to an austenite transformation end temperature or higher is formed;
A second passage is formed through which the wire passes and communicates with both ends of the first passage, and two guide portions provided so as to protrude from the wall surface of the heating portion;
Cooling means for cooling the guide portion;
A heating furnace comprising: The cooling means is
The guide part is formed of a material having a higher thermal conductivity than the material forming the guide part, the guide part is connected to a fixed part having a larger heat capacity than the guide part, and the guide part is cooled by heat conduction. The heating furnace according to claim 6. The cooling means is
The heating furnace according to claim 6, wherein the heating furnace blows air to the guide portion. The cooling means is
The heating furnace according to claim 6, wherein the heating furnace is a radiator attached to the guide portion. A heating furnace according to any one of claims 6 to 9,
Heating means for heating the heating section of the heating furnace;
A heating part temperature sensor for detecting the temperature of the heating part;
A control circuit for controlling the heating means based on the temperature detected by the heating unit temperature sensor;
A heating device comprising: A guide part temperature sensor for detecting the temperature of the guide part;
The control circuit includes:
The heating device according to claim 10, wherein the cooling unit is controlled based on a temperature detected by the guide part temperature sensor.

Images