JP2017119294A - Solder iron - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solder iron which has a low cost and high reliability by simplifying a configuration relating to temperature control, in the solder iron formed of a plurality of iron tips each provided with a heater.SOLUTION: A solder iron includes a plurality of iron tips configured such that a tip part can melt solder and a temperature control means which controls a temperature of the iron tips. Therein, each of the iron tips has a heater connected in series or in parallel and a thermo-couple which generates a thermoelectromotive force in accordance with the temperature of the tip part, respective thermo-couples are all connected in series with each other to form a thermocouple group, a plurality of resistances are connected in series between one end of the thermo-couple group and the other end, a divided voltage potential between each other of the plurality of resistances connected in series with one end of the thermocouple is inputted to the temperature control means as a temperature signal, and temperature control means performs feedback control of the heater based on the temperature signal.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a soldering iron having a plurality of tips.

  Conventionally, a soldering iron having a plurality of tips for melting solder is known. As an example of such a soldering iron provided with a plurality of tips, Patent Document 1 describes that an electrical component such as an IC chip is sandwiched between contact pieces provided at the tips of a pair of movable legs and a contact piece. A device (electric component removing device) is disclosed in which the solder that fixes the electrical component to the circuit board is heated to a molten state, and the electrical component is removed from the circuit board in this state.

  In this electrical component removing device, each leg is individually heated by a heater provided individually in each leg, thereby heating the contact piece provided at the tip of each leg and using the heat of the contact piece. Melt the solder. Such an electrical component removing device is an example of a soldering iron having a plurality of tips.

JP 2004-058064 A

A soldering iron having a plurality of tips as described above is provided with a heater for each of the tips, so that a heater control circuit (temperature control means) is formed for each heater. . For example, in the case of a soldering iron provided with two tips, since two heaters are formed, there are some in which two heater control circuits are provided corresponding to each heater. On the other hand, some heaters control a plurality of heaters with a single heater control circuit. In this case, the heater control circuit can be configured to control a plurality of heaters, or the control software can control a plurality of heaters. It has become.
However, a soldering iron provided with a plurality of heater control circuits corresponding to the number of heaters, i.e., the number of tips, complicates the circuit configuration and causes a decrease in reliability and an increase in manufacturing cost. In addition, in a soldering iron that controls a plurality of heaters with a single heater control circuit, the circuit configuration of the heater control circuit itself becomes complicated, or dedicated control software is required, leading to an increase in manufacturing cost. .

  An object of the present invention is to provide a soldering iron having a low cost and a high reliability by simplifying the structure related to temperature control in a soldering iron having a plurality of tips each provided with a heater. is there.

In order to achieve the above object, in the present invention, a soldering iron provided with a plurality of tips whose tip portions are configured to melt the solder, and temperature control means for controlling the temperature of the tip. Because
Each of the tips has a heater connected in series or in parallel, and a thermocouple that generates a thermoelectromotive force according to the temperature of the tip, and the thermocouples are all connected in series. A plurality of resistors connected in series between one end and the other end of the thermocouple group, and between the plurality of resistors connected in series with one end of the thermocouple group. The divided voltage potential is input to the temperature control means as a temperature signal, and the temperature control means feedback-controls the heater based on the temperature signal.

  According to the soldering iron of the present invention having such a configuration, it is easy to connect a plurality of resistance elements between one end and the other end of a thermocouple group composed of a plurality of thermocouples connected in series. An average value of the thermoelectromotive force of a plurality of thermocouples is obtained, and this is input to a temperature control means having a simple configuration corresponding one-to-one with a thermocouple, thereby controlling the temperature control of a plurality of tips. It can be easily performed collectively by means. Thus, for example, temperature control of a soldering iron having a plurality of tips is easily performed at a low cost by providing a plurality of resistance elements without forming a temperature control means for each thermocouple. It becomes possible.

  The temperature signal is an average potential of an electromotive force of each thermocouple.

  The thermocouple is a K-type thermocouple in which an alumel alloy and a chromel alloy are joined.

  According to the present invention, it is possible to provide a low-cost and high-reliability soldering iron by simplifying the structure related to temperature control in a soldering iron formed with a plurality of tips each having a heater. become.

It is a schematic block diagram which shows the electrical structure of the soldering iron which concerns on 1st Embodiment of this invention. It is a block diagram which shows the structure of the control part of FIG. It is a schematic block diagram which shows the electrical structure of the soldering iron which concerns on 2nd Embodiment of this invention. It is a schematic block diagram which shows the electrical structure of the soldering iron which concerns on 3rd Embodiment of this invention.

Embodiments of the present invention will be described below with reference to the drawings.
(First embodiment)
FIG. 1 is a schematic configuration diagram showing an electrical configuration of the soldering iron according to the first embodiment.
The soldering iron 10 of the present embodiment includes two tips 11A and 11B and one control unit (temperature control means) 21 that controls the temperature of each tip.
The tips 11A and 11B accommodate heater wires 12A and 12B and thermocouples 13A and 13B, respectively.

  The heater wires 12A and 12B are made of, for example, an aluminum-containing iron-chromium alloy wire, a tungsten wire, a nichrome wire, and the like, and are wound in a coil shape inside the tips 11A and 11B. The heater wire 12A formed on the tip 11A and the heater wire 12B formed on the tip 11B are electrically connected in series and controlled through the control unit 21.

  The thermocouples 13A and 13B are formed by joining metal wires made of different metal materials in the vicinity of the tips 11Ap and 11Bp of the tips 11A and 11B. As the thermocouples 13A and 13B, for example, a K-type thermocouple such as an alumel-chromel joint, an E-type thermocouple such as a chromel-constantan joint, or a J-type thermocouple such as an iron-constantan joint can be used. . These thermocouples 13A and 13B are portions where metal wires made of different metal materials are joined to each other, and a thermoelectromotive force is generated by the Seebeck effect. Also, a sensor that works in the same way as a thermocouple can be applied.

  The thermocouple 13A formed on the tip 11A and the thermocouple 13B formed on the tip 11B are electrically connected in series to form a thermocouple group 13S. A plurality of resistance elements 15A and 15B are connected in series between the one end side 13Sa and the other end side 13Sb of the thermocouple group 13S. In the present embodiment, the resistance elements 15A and 15B use resistance elements having the same resistance value.

  The voltage dividing potential between the one end 13Sa of the thermocouple group 13S and the resistance element 15A and the resistance element 15B is used as a temperature signal indicating the average temperature of the tip 11A and the tip 11B. ) 21.

FIG. 2 is a block diagram showing a configuration of the control unit of FIG.
The control unit (temperature control means) 21 includes an electromotive force measurement circuit 22, a temperature compensation circuit 23, a reference temperature setting circuit 24, a heater control circuit 25, and an operational amplifier 26.

  The electromotive force measurement circuit 22 uses a temperature signal indicating a divided potential that is an average value of the total potential of the thermoelectromotive force generated in the thermocouple group 13S, that is, the thermoelectromotive force of the thermocouple 13A and the thermoelectromotive force of the thermocouple 13B. Measure as The temperature compensation circuit 23 performs temperature compensation on the electromotive force measurement circuit 22 according to the number of thermocouples (two in the present embodiment).

  The reference temperature setting circuit 24 sets the temperatures of the tips 11A and 11B. The operational amplifier 26 outputs a difference signal between the set temperature (reference temperature) set by the reference temperature setting circuit 24 and the actual temperatures of the tips 11A and 11B measured by the electromotive force measurement circuit 22.

  Based on the difference signal output from the operational amplifier 26, the heater control circuit 25 is connected to the heater wires 12A and 12B connected in series so that the temperatures of the tips 11A and 11B become the set temperature (reference temperature). Control energization.

The operation of the soldering iron 10 according to the first embodiment having the above configuration will be described with reference to FIGS.
The soldering iron 10 of this embodiment is controlled so that the temperature of the tip 11A is equal to the temperature of the tip 11B. Therefore, the actual tips 11A and 11B based on the set temperature (reference temperature) arbitrarily set by the reference temperature setting circuit 24 and the thermoelectromotive force of the thermocouple group 13S measured by the electromotive force measuring circuit 22 are used. The temperature (measured temperature) and the difference are detected. The heater control circuit 25 controls energization of the heater wires 12A and 12B connected in series according to the difference.

  For example, when the measured temperatures of the tips 11A and 11B measured by the electromotive force measuring circuit 22 are lower than the set temperature set by the reference temperature setting circuit 24, the heater control circuit 25 energizes the heater wires 12A and 12B. To continue. On the other hand, when the measured temperatures of the tips 11A and 11B measured by the electromotive force measuring circuit 22 are the same as or higher than the set temperature set by the reference temperature setting circuit 24, the heater control circuit 25 applies the heater wires 12A and 12B to the heater wires 12A and 12B. Do not energize.

  In addition to the ON-OFF control described above, the heater control circuit 25 is based on the difference between the set temperature of the reference temperature setting circuit 24 and the actually measured temperature measured by the electromotive force measurement circuit 22. The configuration may be such that energization control of the heater wires 12A, 12B is performed by variable voltage control that arbitrarily varies the energization voltage of 12B.

  In order to control the tip 11A and the tip 11B to be isothermal in this way, the heater wire 12A, 12B having the same resistance value is used to form the control unit (temperature control means) 21. It is necessary to input to the power measurement circuit 22 a divided potential that is an average value of the total potential of the thermoelectromotive force of the thermocouple 13A and the thermoelectromotive force of the thermocouple 13B as a temperature signal.

  In the soldering iron 10 of the present embodiment, in order to obtain such a divided potential, a thermocouple group 13A and a thermocouple 13B are connected in series between one end side 13Sa and the other end side 13Sb of the thermocouple group 13S. A potential between a connection point J1 between the resistance element 15A and the resistance element 15B connected in series and one end 13Sa of the thermocouple group 13S is input to the electromotive force measurement circuit 22 as a temperature signal.

  The potential between the connection point J1 and the one end 13Sa of the thermocouple group 13S is an average potential of the thermoelectromotive force obtained by adding the thermoelectromotive force of the thermocouple 13A and the thermoelectromotive force of the thermocouple 13B. That is, the temperature signal indicates an average temperature of the temperature of the tip 11A and the temperature of the tip 11B.

For example, when the electromotive force of the thermocouple 13A formed on the tip 11A is E1, and the electromotive force of the thermocouple 13B formed on the tip 11B is E2, one end side 13Sa and the other end of the thermocouple group 13S The potential E3 between the side 13Sb is expressed by the following equation (1).
E3 = E1 + E2 (1)

When the resistance value of the resistance element 15A is R1 and the resistance value of the resistance element 15B is R2, the distance between the connection point J1 between the resistance element 15A and the resistance element 15B and the one end 13Sa of the thermocouple group 13S. Since the potential E4 is R1 = R2, it is expressed by the following formula (2).
E4 = E3 / 2 (2)

  Thus, even when the temperatures of the tip 11A and the tip 11B are different, the potential E4 serving as a temperature signal input to the electromotive force measurement circuit 22 constituting the control unit (temperature control means) 21 is It becomes an average value of the thermoelectromotive force of the thermocouple 13A and the thermoelectromotive force of the thermocouple 13B.

  Then, based on a difference signal between the temperature signal that is an average value of the thermoelectromotive force of the thermocouple 13A and the thermoelectromotive force of the thermocouple 13B and the set temperature (reference temperature) set by the reference temperature setting circuit 24. The energization of the heater wires 12A and 12B connected in series is controlled so that the temperatures of the tips 11A and 11B become the set temperature (reference temperature).

  As described above, according to the soldering iron 10 according to an embodiment of the present invention, between the one end 13Sa and the other end 13Sb of the thermocouple group 13S composed of two thermocouples 13A and 13B connected in series, For example, a temperature signal that is an average value (divided potential) of the thermoelectromotive force of the thermocouple 13A and the thermoelectromotive force of the thermocouple 13B simply by connecting a plurality of resistance elements 15A and 15B having the same resistance value. Is obtained, and this is input to one control unit (temperature control means) 21 so that the temperature control of the plurality of tips 11A and 11B can be easily performed collectively by one control unit (temperature control means) 21. It can be carried out.

  Thus, for example, a plurality of control units (temperature control means) can be formed for each thermocouple, or a control unit having a complicated circuit configuration capable of controlling a plurality of thermocouples can be used. By simply providing a resistance element, it becomes possible to control the temperature of a soldering iron having a plurality of tips easily and at low cost.

(Second Embodiment)
FIG. 3 is a schematic configuration diagram showing an electrical configuration of the soldering iron according to the second embodiment.
In addition, the same number is attached | subjected to the member of the same structure as 1st Embodiment shown in FIG.1, 2, The detailed description is abbreviate | omitted.
The soldering iron 30 of the present embodiment includes a thermocouple 13A that generates a thermoelectromotive force according to the temperature of the tip 11A, and a thermocouple 13B that generates a thermoelectromotive force according to the temperature of the tip 11B. The thermocouple 13A and the thermocouple 13B are connected in series to form a thermocouple group 13S. A plurality of resistance elements 35A and 35B are connected in series between the one end side 13Sa and the other end side 13Sb of the thermocouple group 13S. Among these, the resistance element 35B is a variable resistance element.

  In the soldering iron 30 having such a configuration, by setting the resistance value of the resistance element 35B, which is a variable resistance element, to an arbitrary value, a reference temperature setting circuit 24 (see FIG. The temperature of the tips 11A and 11B can be set regardless of the temperature setting of 2).

For example, when the electromotive force of the thermocouple group 13S is E3, the resistance value of the resistance element 35A is R1, and the set resistance value of the resistance element 35B made of a variable resistance element is VR2, the resistance between the resistance element 35A and the resistance element 35B A potential E4 (temperature signal) between the connection point J1 and one end 13Sa of the thermocouple group 13S is represented by the following equation (3).
E4 = VR2 / (R1 + VR2) × E3 (3)

  For example, when the set resistance value VR2 of the resistance element 35B is set to be smaller than the resistance value R1 of the resistance element 35A (VR2 <R1), E4> (E3 / 2) is satisfied, so that the control unit (temperature control means) ) The temperature signal input to 21 is input so as to be a lower value than when the resistance values of the resistance element 35A and the resistance element 35B are equal. As a result, the controller (temperature control means) 21 recognizes that the temperatures of the tips 11A and 11B are lower than the set value of the reference temperature setting circuit 24 (see FIG. 2), and the heater wires 12A and 12B. The temperature of the tips 11A and 11B is further increased by the energization control. As a result, the temperatures of the tips 11A and 11B are raised regardless of the temperature setting of the reference temperature setting circuit 24 (see FIG. 2).

  Further, for example, when the set resistance value VR2 of the resistance element 35B is set to be larger than the resistance value R1 of the resistance element 35A (VR2> R1), E4 <(E3 / 2), so that the control unit (temperature The temperature signal input to the control means 21 is input so as to have a higher value than when the resistance values of the resistance elements 35A and 35B are equal. As a result, the control unit (temperature control means) 21 recognizes that the temperatures of the tips 11A and 11B are higher than the set value of the reference temperature setting circuit 24 (see FIG. 2), and the heater wires 12A and 12B. The temperature of the tips 11A and 11B is lowered by stopping energization. As a result, the temperatures of the tips 11A and 11B are lowered regardless of the temperature setting of the reference temperature setting circuit 24 (see FIG. 2).

  Thus, by making one of the plurality of resistance elements a variable resistance element, for example, if the resistance value setting switch of the resistance element 15B is formed on the gripping portion of the soldering iron 30, the soldering operation is in progress. It is also possible to temporarily increase or decrease the temperature setting of the tips 11A and 11B at hand.

(Third embodiment)
FIG. 4 is a schematic configuration diagram showing an electrical configuration of a soldering iron according to the third embodiment.
In addition, the same number is attached | subjected to the member of the same structure as 1st Embodiment shown in FIG.1, 2, The detailed description is abbreviate | omitted. Also, the heater wire is omitted.
The soldering iron 40 of this embodiment is an example in which three or more tips 11A, 11B, 11C,. Even when such many n tips 11A, 11B, 11C... 11n are formed, the thermocouples 13A, 13B, 13C... 13n corresponding to the respective tips are all connected in series. A connection point between the resistance element 15A and the resistance element 15B by connecting a plurality of resistance elements 15A and 15B having the same resistance value in series between the one end side 13Sa and the other end side 13Sb of the thermocouple group 13Sn. The average electromotive force of all the thermocouples 13A, 13B, 13C,... 13n can be easily obtained between J1 and one end 13Sa of the thermocouple group 13Sn. The resistance values of the resistance elements 15A and 15B are selected so that the potential between the connection point J1 and one end 13Sa of the thermocouple group 13Sn is 1 / the number n of thermocouples.

  If such an average electromotive force is input to the control unit 21 as a temperature signal, all the tips of the soldering irons 40 having three or more tips 11A, 11B, 11C,. It becomes possible to easily control the temperature collectively.

  As mentioned above, although some embodiment of this invention was described, these embodiment is shown as an example and is not intending limiting the range of invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and the equivalents thereof.

  The circuit configuration shown in the first to third embodiments and the connection form between the components are examples, and include an electrically equivalent circuit configuration. For example, the number of resistance elements formed between one end and the other end of the thermoelectric element group is not limited to two as in each of the above-described embodiments, and voltage is divided by connecting three or more resistance elements. A circuit can also be formed.

DESCRIPTION OF SYMBOLS 10 Soldering iron 11A, 11B Tip 12A, 12B Heater wire 13A, 13B Thermocouple 21 Control part

Claims (3)

A soldering iron comprising a plurality of tips whose tip portions are configured to be able to melt solder, and temperature control means for controlling the temperature of the tip,
The tips each have a heater connected in series or in parallel, and a thermocouple that generates a thermoelectromotive force according to the temperature of the tip,
All the thermocouples are connected in series to form a thermocouple group, and a plurality of resistors are connected in series between one end and the other end of the thermocouple group,
The divided potential between a plurality of resistors connected in series with one end of the thermocouple group is input to the temperature control means as a temperature signal,
The temperature control means feedback controls the heater based on the temperature signal.   The soldering iron according to claim 1, wherein the temperature signal is an average potential of an electromotive force of each of the thermocouples.   3. The soldering iron according to claim 1, wherein the thermocouple is a K-type thermocouple in which an alumel alloy and a chromel alloy are joined.

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