Soldering iron

Abstract

To accurately detect the temperature of an iron tip part by a temperature detection part regardless of whether the temperature detection part is in contact with the iron tip part or not.SOLUTION: A soldering iron includes an iron tip portion in which a cavity portion is formed, a temperature detection portion which is positioned in the cavity portion and detects a temperature of the iron tip portion, and a holding portion which is inserted into the cavity portion and holds the temperature detection portion on a front end side, and a depth Ld of the cavity portion and a length Lg between a front end portion of the inserted holding portion and a facing portion facing the front end portion of the cavity portion satisfy a predetermined relational equation (0 ≤ Lg ≤ 0. 25Ld).SELECTED DRAWING: Figure 2A

Description

[Technical Field]

[0001] The technology of the present disclosure relates to a soldering iron. [Background technology]

[0002] A conventional soldering iron includes a heater for heating the tip, a sensor with a temperature detector for detecting the temperature of the tip, and a control device for controlling the heater. The control device detects temperature changes in the tip based on the output from the sensor and controls the heater to restore the temperature of the tip, which may have dropped during soldering, to a set temperature. The temperature detector of the sensor contacts the inner surface of the tip. Such a soldering iron is disclosed in Patent Document 1, etc.

[0003] When the temperature detection part of the sensor is in contact with the inner surface of the soldering iron tip, ensuring contact between the inside of the soldering iron tip and the temperature detection part during manufacturing is important for the accuracy of temperature detection of the soldering iron tip. Therefore, if the inside of the soldering iron tip and the temperature detection part do not make contact during manufacturing, temperature detection will vary. Furthermore, even if the inside of the soldering iron tip and the temperature detection part make contact during manufacturing, temperature changes due to temperature control in actual operation may cause thermal expansion and deformation of the metal, and the inside of the soldering iron tip and the temperature detection part may subsequently lose contact. In such cases, temperature detection will also vary.

[0004] Therefore, it is conceivable to detect the temperature of the iron tip using a temperature detection unit that does not come into direct contact with the iron tip. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2019-171469 Summary of the Invention [Problem to be solved by the invention]

[0006] However, when detecting the temperature of the iron tip using a temperature detection unit that does not come into contact with the iron tip, there is a gap between the iron tip and the temperature detection unit, so the temperature detection unit that does not come into contact with the iron tip may not be able to detect the temperature of the iron tip accurately.

[0007] The technology disclosed herein has been developed in consideration of the above facts, and aims to provide a soldering iron that can accurately detect the temperature of the soldering iron tip using a temperature detection unit, whether or not the temperature detection unit is in contact with the soldering iron tip. [Means for solving the problem]

[0008] In order to achieve the above-mentioned object, a soldering iron according to a first aspect of the disclosed technology comprises a soldering tip portion in which a cavity is formed, a temperature detection portion located within the cavity portion for detecting the temperature of the soldering tip portion, and a holding portion inserted into the cavity portion for holding the temperature detection portion.

[0009] The depth Ld of the hollow portion and the distance Lg between the tip end of the inserted holding portion and the opposing portion of the hollow portion opposing the tip end satisfy the following relational expression. 0≦Lg≦0.25Ld

[0010] A second aspect of the soldering iron comprises a tip portion in which a cavity is formed, a temperature detection portion located within the cavity portion for detecting the temperature of the tip portion, and a holding portion inserted into the cavity portion for holding the temperature detection portion at its tip end.

[0011] The area Sd of the holding portion in contact with the inner surface of the hollow portion when the holding portion is inserted into the hollow portion and the area Sg of the inner surface of the hollow portion between the tip of the holding portion and an opposing portion of the hollow portion that faces the tip of the hollow portion satisfy the following relational expression: Soldering iron. 0≦Sg≦0.25Sd [Effects of the Invention]

[0012] The technology disclosed herein allows the temperature detection unit to accurately detect the temperature of the iron tip, whether or not the temperature detection unit is in contact with the iron tip. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a diagram showing the structure of a soldering iron. [Figure 2A] FIG. 2A is a diagram showing the position of the temperature detection unit inside the tip of the iron tip. [Figure 2B] FIG. 2B is a diagram showing an example of a state in which the thermal conductor has been conveniently moved downward from the second housing portion. [Figure 3] Figure 3 is a graph showing the results of an experiment in which the temperature of the tip of the iron was gradually increased while the actual temperature of the tip of the iron was detected by another temperature sensor and the temperature of the tip of the iron was detected by the temperature detection unit, and this was done while changing the distance between the temperature detection unit and the tip. [Figure 4] FIG. 4 is a graph showing the temperature change at the tip before and after soldering at time t1. [Figure 5] FIG. 5 is a graph showing the temperature change of the iron tip detected by the temperature detection unit when the distance Lg1 does not satisfy the first relationship (0≦Lg1≦0.25Ld). [Figure 6] FIG. 6 is a graph showing the temperature change of the iron tip detected by the temperature detection unit when the distance Lg1 satisfies the first relationship (0≦Lg1≦0.25Ld). DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, embodiments of the technology of the present disclosure will be described with reference to the drawings.

[0015] [Overall configuration] Fig. 1 is a diagram showing the configuration of a soldering iron 1A. Fig. 1 also shows a cross section of a tip 2 and a body 3, as well as a side view of a heater 10A. As shown in Fig. 1, the soldering iron 1A includes a cylindrical body 3, a tip 2 that is connected to the body 3 by inserting the body 3, a heater 10A that heats the tip 2, a thermal conductor 34, and a support 40.

[0016] Soldering iron 1A is an example of the "soldering iron" of the technology of the present disclosure. Soldering iron tip 2 is an example of the "soldering iron" of the technology of the present disclosure.

[0017] <Trouser body 3> The cylindrical trowel body 3 has a portion that is inserted into the trowel tip 2 and a portion that is not inserted into the trowel tip 2. The portion of the trowel body 3 that is not inserted into the trowel tip 2 has first to third trowel body portions that correspond to the inner diameters. The first trowel body portion has an inner diameter that is the same as the first inner diameter of the portion of the trowel body 3 that is inserted into the trowel tip 2. The second trowel body portion has an inner diameter that gradually increases from the first inner diameter as it gets farther away from the trowel tip 2. The third trowel body portion has an inner diameter that remains constant and is the same as the largest inner diameter of the second trowel body portion. The trowel body 3 as a whole is made of a single material. The trowel body 3 is made of a metal such as stainless steel, for example. If the soldering iron 1A is a manual type, a handle is attached to the iron body 3, and if it is an automatic type, a robot hand or the like is attached to the iron body 3.

[0018] <Trouser tip 2> The iron tip 2 has a tip 2a for soldering. The tip 2a has a shape that gradually tapers to a point. Inside the iron tip 2, a housing 4 for housing the heater 10A is provided. The housing 4 has a first housing 4a, a second housing 4b, and a third housing 4ab that correspond to the inner diameter.

[0019] The first housing portion 4a is a cylindrical portion having a circular cross section, into which the above-mentioned part of the trowel body 3 is inserted.

[0020] The second housing portion 4b is located forward (toward the tip portion 2a) of the first housing portion 4a. The second housing portion 4b includes a tip portion 4b1 and a cylindrical portion 4b2. The tip portion 4b1 of the second housing portion 4b has a conical surface shape that tapers in the depth direction (toward the left in FIG. 1). The inner diameter of the cylindrical portion 4b2 of the second housing portion 4b is smaller than the inner diameter of the first housing portion 4a.

[0021] The third housing portion 4ab is located between the first housing portion 4a and the second housing portion 4b. The inner diameter of the third housing portion 4ab gradually increases from the inner diameter of the second housing portion 4b to the inner diameter of the first housing portion 4a as it moves away from the second housing portion 4b.

[0022] The second housing portion 4b is an example of the "hollow portion" of the technology of the present disclosure. The cylindrical portion 4b2 of the second housing portion 4b is an example of the "first portion" of the technology of the present disclosure.

[0023] <Heater 10A> The heater 10A includes a bobbin 11, a heater wire 20 that generates heat when energized, and a temperature sensor 30 that detects the temperature of the iron tip 2.

[0024] (Bobbin 11) The bobbin 11 has a cylindrical shape. The bobbin 11 is made of an electrically insulating material. The bobbin 11 is arranged along the axis L. A pair of sensor mounting holes (not shown) are formed inside the bobbin 11 and penetrate the bobbin 11 along the axis L. One end of the pair of sensor mounting holes opens at the end face of the base end (the end away from the tip portion 2a) of the bobbin 11, and the other end opens at the tip (the end closer to the tip portion 2a) of the bobbin 11. Two metal wires (not shown) (details of which will be described later) that form the temperature sensor 30 are inserted into the pair of sensor mounting holes.

[0025] (heater wire 20) The heater wire 20 includes two filaments 20A and 20B that are parallel to each other and have the same shape. The two filaments 20A and 20B are wound spirally (i.e., out of phase with each other) around the outer periphery of the bobbin 11.

[0026] (Temperature sensor 30) The temperature sensor 30 is a thermocouple formed by joining the tips of two different metal wires. The joint where the tips of the two metal wires are joined is the temperature detection unit 33. The temperature detection unit 33 is located inside the second housing 4b. The two metal wires are located in a housing hole formed in a thermal conductor 34 (described later), an insertion hole formed in the support body 40, and a pair of sensor mounting holes formed in the bobbin 11 described above. The other end of the temperature sensor 30 (i.e., the end opposite the joint) is connected to a control device (not shown).

[0027] <Thermal Conductor 34> The thermal conductor 34 conducts heat from the iron tip 2 to the temperature detection portion 33 of the temperature sensor 30. The thermal conductor 34 includes a cylindrical portion 34b1 and a tip portion 34b2 that tapers to a taper.

[0028] The temperature detecting unit 33 is fixed to the thermal conductor 34. Specifically, first, an accommodation hole (not shown) for accommodating the temperature sensor 30 is formed inside the thermal conductor 34. The cross section of the accommodation hole inside the thermal conductor 34 is slightly smaller than the cross section of the temperature detecting unit 33. The temperature sensor 30 is inserted from the other end to the temperature detecting unit 33 into the front end of the accommodation hole, and the temperature detecting unit 33 is press-fit into the accommodation hole, thereby fixing the temperature detecting unit 33 to the thermal conductor 34. In other words, the thermal conductor 34 holds the temperature detecting unit 33 so that it is positioned at the end of the thermal conductor 34 on the front end portion 4b1 side. The temperature detecting unit 33 and the thermal conductor 34 can be brought into close contact with each other, thereby improving the sensitivity of temperature detection of the heat from the iron tip 2.

[0029] The temperature detecting portion 33 does not protrude from the thermal conductor 34. However, the temperature detecting portion 33 may protrude from the thermal conductor 34 as long as it is in contact with the thermal conductor 34.

[0030] The outer diameter of the columnar portion 34b1 of the thermal conductor 34 is slightly larger than the inner diameter of the cylindrical portion 4b2 of the second housing portion 4b. The thermal conductor 34 is press-fitted into the second housing portion 4b. This allows the columnar portion 34b1 of the thermal conductor 34 to be tightly attached to the inner surface of the cylindrical portion 4b2 of the second housing portion 4b, improving the sensitivity of temperature detection of the heat at the tip portion 2a.

[0031] The thermal conductor 34 has a thermal conductivity equal to or greater than that of the temperature detection unit 33 (i.e., the joint where the tip ends of the two types of metal wires are joined). Specifically, the two types of metal wires are made of, for example, nickel and chromium. On the other hand, the thermal conductor 34 may be made of, for example, iron, steel, brass, phosphor bronze, beryllium copper, aluminum, duralumin, nickel, silver, gold, or other metals.

[0032] The thermal conductivity of the thermal conductor 34 is within a predetermined range that includes the thermal conductivity of the trowel tip 2. Specifically, the thermal conductivity of the thermal conductor 34 may be equal to the thermal conductivity of the trowel tip 2, or may be a predetermined value smaller than or larger than the thermal conductivity of the trowel tip 2. In addition to the case where the thermal conductor 34 and the trowel tip 2 are made of the same metal material, for example, the trowel tip 2 may be made of copper and the thermal conductor 34 may be made of a material whose thermal conductivity is smaller or larger than that of copper by a predetermined value.

[0033] The heat conductor 34 may be coated with a heat transfer layer containing inorganic particles of diamond powder. By disposing diamond powder, which has excellent thermal conductivity, on the surface of the heat conductor 34, the heat transfer properties of the heat conductor 34 can be further improved.

[0034] The thermal conductor 34 is an example of a "holding portion" of the technology of the present disclosure. The tip portion 34b2 is an example of a "tip portion" of the technology of the present disclosure. The columnar portion 34b1 is an example of a "second portion" of the technology of the present disclosure.

[0035] <Support 40> The support 40 supports the thermal conductor 34. The support 40 has a cylindrical portion 40s whose outer diameter is smaller than the inner diameter of the first housing portion 4a, and a flange portion 40f formed only on one end (tip side) of the cylindrical portion 40s. An insertion hole (not shown) is formed in the cylindrical portion 40s and the flange portion 40f. The end of the flange portion 40f along the axis L contacts the inner surface of the first housing portion 4a of the housing portion 4, and the left side of the flange portion 40f in FIG. 1 (the end away from the cylindrical portion 40s) contacts the inner surface of the third housing portion 4ab. Therefore, the support 40 cannot move toward the tip 2a of the iron tip 2. The tip side of the bobbin 11 is inserted into the insertion hole in the cylindrical portion 40s. The thermal conductor 34 is fixed to the side surface (left end in FIG. 1) of the flange portion 40f that is perpendicular to the axis L direction.

[0036] The cylindrical portion 40s and the flange portion 40f are arranged along the axis L. The outer diameter of the cylindrical portion 40s is smaller than the outer diameter of the flange portion 40f. The axial side surface of the cylindrical portion 40s is located closer to the axis L than the axial side surface of the flange portion 40f. Therefore, a gap is formed between the axial side surface of the cylindrical portion 40s and the first housing portion 4a. A portion (tip side) of the trowel body 3 is inserted into this gap. The thickness of the gap is the same as the thickness of the portion (tip side) of the trowel body 3. Therefore, the portion (tip side) of the trowel body 3 is not press-fitted into the gap. The portion of the trowel tip 2 around the gap where the portion (tip side) of the trowel body 3 is inserted is crimped. This is to increase the density of the trowel tip 2, i.e., to make it more closely fitted, thereby reducing air with poor thermal conductivity and facilitating heat transfer from the heater 10A to the trowel tip 2.

[0037] The thermal conductor 34 and the support 40 are not limited to being constructed separately. Specifically, the thermal conductor 34 and the support 40 may be constructed using only the same material as the thermal conductor 34, that is, they may be constructed integrally.

[0038] [Position of the thermal conductor 34 in the second housing portion 4b] Next, the position of the thermal conductor 34 in the second housing portion 4b will be described.

[0039] Fig. 2A is a diagram showing an example of the state in which the thermal conductor 34 is positioned inside the second housing portion 4b, and Fig. 2B is a diagram showing an example of the state in which the thermal conductor 34 has been conveniently moved downward from the second housing portion 4b.

[0040] The depth of the second housing portion 4b is defined as Ld. The distance between the tip end 34b2 of the inserted thermal conductor 34 and the inner surface 4bs of the second housing portion 4b facing the tip end 34b2 is defined as Lg1. In the soldering iron 1A of this embodiment, the thermal conductor 34 is arranged so that Ld and Lg1 satisfy the following first relational expression: 0≦Lg1≦0.25Ld (1)

[0041] Furthermore, Sd denotes the area of ​​contact between the thermal conductor 34 and the inner surface of the cylindrical portion 4b2 of the second housing portion 4b when the thermal conductor 34 is inserted into the second housing portion 4b. Sg denotes the area between the tip end 34b2 of the thermal conductor 34 and the inner surface 4bs of the second housing portion 4b that faces the tip end 34b2, on the inner surface of the cylindrical portion 4b2 of the second housing portion 4b. In the soldering iron 1A of this embodiment, the thermal conductor 34 is arranged so that Sd and Sg satisfy the following second relational expression: 0≦Sg≦0.25Sd (2)

[0042] Each relational expression will be explained below.

[0043] (First relational expression (1)) As shown in the upper side of Fig. 2B, the tip portion 4b1 and the cylindrical portion 4b2 of the second housing portion 4b meet at a boundary line 17bL1. The boundary line 17bL includes the axis L of the second housing portion 4b and includes an upper end position 17s and a lower end position 17t in a cross section taken along the vertical direction in Fig. 2B.

[0044] As shown in the lower part of Fig. 2B, the cylindrical portion 34b1 and the tip end 34b2 of the thermal conductor 34 meet at a boundary line 34bL1. The boundary line 34bL1 includes the axis L of the thermal conductor 34 and includes an upper end position 34bs and a lower end position 34bt in a cross section taken along the vertical direction in Fig. 2B.

[0045] 2B, the upper end position 17bs and the lower end position 17bt of the cylindrical portion 4b2 respectively coincide with the upper end position 34bs and the lower end position 34bt of the columnar portion 34b1. A circle having its center on the axis L and passing through the upper end position 17bs and the lower end position 17bt is defined as a boundary line 17bL2. The position of the boundary line 34bL1, which has its center on the axis L and passes through the upper end position 34bs and the lower end position 34bt, coincides with the position of the boundary line 17bL2.

[0046] As shown in the upper side of Fig. 2B, the right end (the end farthest from the tip portion 4b1) of the cylindrical portion 4b2 of the second housing portion 4b includes the axis L at the right end and includes an upper end position 17r and a lower end position 17q in a cross section taken along the vertical direction in Fig. 2B. A circle having the axis L as its center and passing through the upper end position 17r and the lower end position 17q is a boundary line 17bL3 between the cylindrical portion 4b2 and the third housing portion 4ab.

[0047] The right end (the end farthest from the tip 34b2) of the portion of the thermal conductor 34 inserted into the second housing portion 4b coincides with the right end (the end farthest from the tip 4b1) of the cylindrical portion 4b2 of the second housing portion 4b. The right end (the end farthest from the tip 34b2) of the portion of the thermal conductor 34 inserted into the second housing portion 4b is a circle 34bL2 that coincides with the boundary line 17bL3. The circle 34bL2 includes the axis L and includes an upper end position 34r and a lower end position 34q in a cross section taken along the vertical direction in FIG. 2B. The upper end position 34r and the lower end position 34q coincide with the upper end position 17r and the lower end position 17q, respectively.

[0048] The distance between the tip 34b2 of the inserted thermal conductor 34 and the inner surface 4bs facing the tip 34b2 in the second accommodating section 4b, specifically, the distance between the boundary line 17bL1 and the boundary line 17bL2, in other words, the distance between the upper end position 17s and the upper end position 17bs or the upper end position 34bs, is defined as distance Lg1.

[0049] The depth of the second storage section 4b, specifically, the length along the axis L of the cylindrical portion 4b2 of the second storage section 4b, more specifically, the distance between the boundary line 17bL1 and the boundary line 17bL3, in other words, the distance between the upper end position 17s and the upper end position 17r, is defined as distance Ld.

[0050] In this embodiment, the thermal conductor 34 is disposed so that the distance Lg1 and the distance Ld have the following relationship (first relationship): 0≦Lg1≦0.25Ld (1)

[0051] In this way, the thermal conductor 34 is inserted into the cylindrical portion 4b2 so that the above relationship (first relationship) is satisfied. As described above, the thermal conductor 34 holds the temperature detection unit 33 so that it is located at the end of the thermal conductor 34 on the side of the tip portion 4b1.

[0052] (Second relational expression) The area between the tip 34b2 of the thermal conductor 34 and the inner surface 4bs facing the tip 34b2 of the second accommodating portion 4b on the inner surface of the cylindrical portion 4b2 is defined as Sg, in other words, the area between the boundary line 17bL1 and the boundary line 17bL2 on the inner surface of the cylindrical portion 4b2 of the second accommodating portion 4b.

[0053] Furthermore, Sd denotes the area where the thermal conductor 34 comes into contact with the inner surface of the cylindrical portion 4b2 of the second housing portion 4b when the thermal conductor 34 is inserted into the second housing portion 4b, in other words, the area between the boundary line 34bL1 and the circle 34bL2 in the cylindrical portion 34b1 of the thermal conductor 34. In the soldering iron 1A of this embodiment, the thermal conductor 34 is arranged so that Sd and Sg have the following relationship (second relationship): 0≦Sg≦0.25Sd (2)

[0054] In this way, the thermal conductor 34 is inserted into the cylindrical portion 4b2 so that the above relationship (second relationship) is satisfied.

[0055] The distance Lg1 is an example of the "distance Lg" in the technology of the present disclosure. The inner surface 4bs is an example of the "opposing portion" in the technology of the present disclosure.

[0056] The first and second relationships will now be explained in more detail.

[0057] (First relationship) As described above, by generating heat from heater 10A, soldering is performed by heating tip 2 at the tip of soldering iron 1A to a predetermined temperature. During soldering, the temperature of tip 2a of soldering iron tip 2 drops.

[0058] The temperature detector 33 measures the temperature of the tip 2a of the iron tip 2, and the control device performs feedback control (for example, PID (Proportional-Integral-Differential) control) of the magnitude of the current flowing through the heater wire 20 based on the measured temperature information so that the temperature of the tip 2a of the iron tip 2 becomes a predetermined temperature. To perform such feedback control, it is necessary to position the temperature detector 33 in a position where it can quickly detect changes in the temperature of the iron tip 2.

[0059] The greater the distance between the temperature detecting part 33 and the tip 17p, the less quickly the temperature detecting part 33 can detect the change in the temperature of the iron tip part 2.

[0060] Therefore, the inventors conducted the following experiment to determine the distance Lg1 at which the temperature detection unit 33 can quickly detect a change in the temperature of the iron tip 2.

[0061] FIG. 3 is a graph of the experimental results. The experiment was conducted by gradually increasing the temperature of the soldering iron tip 2 of the soldering iron 1A while detecting the actual temperature of the soldering iron tip 2 with another temperature sensor and the temperature of the soldering iron tip 2 with the temperature detection unit 33. This was done while varying the distance Lg1. The graph in FIG. 3 shows the results of this experiment. The solid line (Lg = 0) indicates the actual temperature of the soldering iron tip 2. The line with a black circle on it indicates the temperature when the distance Lg between the upper end position 17s and the upper end position 17bs is 0≦Lg≦0.25Ld, specifically, when Lg = 0.25Ld = (Lg1) (specifically, when Lg1 = Lx (mm)). The dotted line indicates the temperature when the distance Lg is Lg > 0.25Ld, specifically, when Lg = 2 * Lx (mm).

[0062] From this experiment, it was found that when the distance Lg between the upper end position 17s and the upper end position 17bs has the following first relationship, the temperature of the iron tip 2 detected by the temperature detection unit 33 approximately matches the actual temperature of the iron tip 2, that is, it accurately follows the actual temperature changes of the iron tip 2. 0≦Lg≦0.25Ld

[0063] Therefore, it can be said that the temperature detection unit 33 having this relationship is located at a position where it can quickly detect a change in the temperature of the iron tip 2.

[0064] However, if the distance Lg1 does not satisfy the first relationship (i.e., Lg>0.25Ld), the temperature of the iron tip 2 detected by the temperature detection unit 33 will not match the actual temperature of the iron tip 2, i.e., will not follow the actual temperature changes of the iron tip 2. Therefore, it can be said that the temperature detection unit 33 is not located in a position where it can quickly detect changes in the temperature of the iron tip 2.

[0065] Therefore, in this embodiment, the temperature detection unit 33 is positioned at a position where the distance Lg1 satisfies the first relationship (0≦Lg1≦0.25Ld).

[0066] (Second relationship) The inventors also calculated the areas Sg and Sd during the above experiment and found that when the areas Sg and Sd have the following second relationship, the temperature of the iron tip 2 detected by the temperature detection unit 33 accurately follows the actual temperature change of the iron tip 2. 0≦Sg≦0.25Sd

[0067] Therefore, in this embodiment, the temperature detection unit 33 is positioned so that the distance Lg1 satisfies the first relationship (i.e., 0≦Lg1≦0.25Ld) and the area Sg satisfies the second relationship (i.e., 0≦Sg≦0.25Sd).

[0068] The third housing portion 4ab is located at the right end (the end away from the tip portion 4b1) of the cylindrical portion 4b2 of the second housing portion 4b. The first housing portion 4a is located at the right end of the third housing portion 4ab. The third housing portion 4ab and the first housing portion 4a are in contact with each other at an upper end position 17n and a lower end position 17u in a cross section taken along the vertical direction in FIG. 2B. The right end (the end farthest from the tip 34b2) of the columnar portion 34b1 of the thermal conductor 34 and the flange portion 40f of the support body 40 meet at a boundary line 34bL3. The boundary line 34bL3 includes the axis L and includes an upper end position 34s and a lower end position 34t in a cross section taken along the vertical direction in FIG. 2B. The upper end position and the lower end position 40u in a cross section taken along the vertical direction in FIG. 2B at the leftmost end of the region of the flange portion 40f that contacts the inner surface of the first housing portion 4a are upper end position 40p and lower end position 40u, respectively. A line passing through upper end position 17r and upper end position 17n is parallel to a line passing through upper end position 34s and upper end position 40p, and a gap 1740g exists between these lines. Similarly, a line passing through lower end position 17q and lower end position 17u is parallel to a line passing through lower end position 34t and lower end position 40u, and a gap 1740g exists between these lines. 2A and 2B, and the gap 1740g disappears, the distance Lg1 becomes 0 and Sg = 0. In other words, when the distance Lg1 is 0, Sg = 0.

[0069] As described above, the adjustment of the position of the temperature detection unit 33 is performed by adjusting the amount of press-fitting the heat conductor 34 into the second housing portion 4b. The technology of the present disclosure is not limited to this.

[0070] For example, the heat conductor 34 and the second housing portion 4b may be fixed by a screw method. In this case, the adjustment of the position of the temperature detection unit 33 is performed by adjusting the amount of screw rotation.

[0071] Also, the heat conductor 34 and the second housing portion 4b may be fixed by pinning. In this case, the adjustment of the position of the temperature detection unit 33 is performed according to the position of the pin.

[0072] Furthermore, the length from the surface of the heat conductor 34 fixed to the flange portion 40f of the support 40 to the temperature detection unit 33 press-fitted into the accommodation hole in the heat conductor 34 is adjusted in advance.

[0073] In the above example, the distance between the upper end position 17s and the upper end position 34bs is set as Lg1, but the technology of the present disclosure is not limited to this.

[0074] For example, it may be the distance between the temperature detection unit 33 and a point on the inner surface 4bs inside the tip portion 2a, specifically, the distance between the temperature detection unit 33 and the tip 17p.

[0075] By the way, in the present embodiment, the temperature detection unit 33 does not necessarily contact the inner surface 4bs inside the tip portion 2a. That is, 0 < Lg1 and 0 ≦ Sg may be set. This is for the following reasons.

[0076] First, there are two types of soldering irons: those with a structure that makes the temperature detection unit contact the inner surface inside the tip of the iron, and those without such a structure.

[0077] In the case of a structure in which the inside of the tip and the temperature detection part are in contact, it is important to ensure contact between the inside of the tip and the temperature detection part during manufacturing. If the inside of the tip and the temperature detection part do not come into contact during manufacturing, variations in temperature sensing will occur. Also, even if the inside of the tip and the temperature detection part are in contact during manufacturing, due to temperature changes caused by temperature control during actual operation or the like, thermal expansion, deformation, etc. of the metal will occur, and thereafter, the inside of the tip and the temperature detection part may no longer be in contact. In such a case as well, variations in temperature sensing will occur.

[0078] Therefore, in the present embodiment, a structure in which the inside of the tip and the temperature detection part are not intentionally brought into contact (that is, 0 < Lg1 and 0 < Sg) may be adopted.

[0079] [Operation] By causing the heater 10A to generate heat, the tip part 2 at the tip of the soldering iron 1A is heated. In this state, soldering is performed. The temperature detection part 33 measures the temperature of the tip part 2a at the tip of the tip part ②, and the control device performs feedback control (for example, PID control) on the magnitude of the current flowing through the heater wire 20 so that the temperature of the tip part 2a at the tip of the tip part 2 becomes a predetermined temperature based on the measured temperature information.

[0080] FIG. 4 is a graph showing the temperature change of the tip part 2a before and after soldering is performed at time t1. As shown in FIG. 4, the temperature of the tip part 2a at the tip of the tip part 2 decreases due to soldering.

[0081] FIG. 5 is a graph showing the temperature change of the tip part 2 detected by the temperature detection part 33 when the distance Lg1 does not satisfy the above first relationship (0 ≤ Lg1 ≤ 0.25Ld). As shown in FIG. 5, the temperature detection part 33 detects that the temperature of the tip part 2a at the tip of the tip part 2 has decreased at time t2 after time t1 when soldering is performed. Therefore, at time t2 later than time t1, the heater 10A will generate more heat. Therefore, between time t1 and time t2, the temperature of the tip part 2a remains lower than the predetermined temperature, and soldering is not properly performed.

[0082] However, in the present embodiment, the temperature detection unit 33 is positioned such that the distance Lg1 satisfies the above first relationship (i.e., 0 ≦ Lg1 ≦ 0.25Ld), and the area Sg satisfies the above second relationship (i.e., 0 ≦ Sg ≦ 0.25Sd).

[0083] FIG. 6 is a graph showing the temperature change of the tip portion 2 of the soldering iron detected by the temperature detection unit 33 when the distance Lg1 satisfies the above first relationship and the area Sg satisfies the above second relationship. As shown in FIG. 6, the temperature detection unit 33 detects that the temperature of the tip end portion 2a of the tip portion 2 has decreased at the time t1 when soldering is performed. Therefore, the heater 10A is caused to generate more heat at the time t1 when the temperature of the tip end portion 2a of the tip portion 2 has decreased. Accordingly, soldering is appropriately performed.

[0084] [Effect] In the present embodiment, whether or not the temperature detection unit 33 contacts the tip portion 2, the temperature of the tip portion 2 can be accurately detected by the temperature detection unit 33. Specifically, in the present embodiment, the temperature detection unit 33 is positioned such that the distance Lg1 satisfies the above first relationship (i.e., 0 ≦ Lg1 ≦ 0.25Ld), and the area Sg satisfies the above second relationship (i.e., 0 ≦ Sg ≦ 0.25Sd). That is, the temperature detection unit 33 is positioned at a position where the change in the temperature of the tip portion 2 can be quickly detected. Therefore, in the present embodiment, the temperature of the tip portion 2 detected by the temperature detection unit 33 substantially coincides with the actual temperature of the tip portion 2. The temperature of the tip portion 2 can be accurately detected in time by the temperature detection unit 33 that does not directly contact the tip portion 2. Accordingly, in the present embodiment, soldering can be appropriately performed.

[0085] In the present embodiment, as described above, the structure in which the inside of the tip and the temperature detection unit are not intentionally brought into contact (i.e., 0 < Lg1 and 0 < Sg) may be adopted. Therefore, in the present embodiment, it is possible to prevent variations in temperature sensing when the inside of the tip and the temperature detection unit do not come into contact during manufacturing or conversely stop contacting thereafter, as in the case of a structure in which the inside of the tip and the temperature detection unit are brought into contact.

[0086] In the temperature sensor of this embodiment, the temperature detecting portion 33 is fixed to the thermal conductor 34 by press-fitting it into the accommodation hole. This allows the temperature detecting portion 33 and the thermal conductor 34 to be closely attached to each other, improving the sensitivity of temperature detection. This allows the temperature change at the tip of the soldering iron tip 2 to be instantly read and reflected in the control, enabling soldering with higher precision and larger heat capacity.

[0087] In this embodiment, the thermal conductor 34 with the temperature detection unit 33 press-fitted into it is press-fitted into the second housing 4b. This allows the inside of the iron tip to be in close contact with the thermal conductor 34, improving the sensitivity of temperature detection. This allows temperature changes at the tip of the iron tip to be instantly read and reflected in the control, enabling soldering with higher precision and greater heat capacity.

[0088] [Variations] The configurations described above are not limited to the above-described embodiments, and various design modifications are possible within the scope of the claims.

[0089] (First Modification) An electrically insulating filler may be filled between the trowel body 3 and the heater 10A.

[0090] (Second Modification) The temperature sensor 30 is a thermocouple formed by joining the tips of two different metal wires. The technology of the present disclosure is not limited to this. For example, a thermistor using an element whose resistance value changes (increases or decreases) with temperature, or a resistance thermometer element whose resistance value increases linearly with increasing temperature, etc. may also be used.

[0091] (Third Modification) In the above embodiment, the tip portion 4b1 of the second housing portion 4b has a conical surface shape tapering in the depth direction (toward the left in FIG. 1 ), and the tip portion 34b2 of the thermal conductor 34 has a shape that gradually tapers. The technology of the present disclosure is not limited to this. For example, the mutually facing surfaces of the tip portion 4b1 and the tip portion 34b2 may be perpendicular to the axis L.

[0092] (Fourth Modification) In the above embodiment, when the distance Lg1 is 0, the surface of the tip portion 34b2 on the tip portion 4b1 side of the second housing portion 4b other than the temperature detection unit 33 contacts the inner surface 4bs of the tip portion 2a. The technology of the present disclosure is not limited to this. For example, when the distance Lg1 is 0, the surface of the tip portion 34b2 on the tip portion 4b1 side of the second housing portion 4b other than the temperature detection unit 33 does not need to contact the inner surface 4bs of the tip portion 2a. Specifically, when the distance Lg1 is 0, the area Sg does not need to be 0.

[0093] [Note] In light of the above disclosure, the following remarks are proposed:

[0094] (Appendix 1) a trowel tip portion in which a cavity portion is formed; a temperature detection unit located in the hollow portion and detecting the temperature of the iron tip; a holding portion that is inserted into the hollow portion and holds the temperature detection portion at a tip end thereof; Equipped with The depth Ld of the hollow portion and the distance Lg between the tip end of the inserted holding portion and the opposing portion of the hollow portion opposing the tip end satisfy the following relational expression: Soldering iron. 0≦Lg≦0.25Ld The holding portion holds the temperature detection portion so that the temperature detection portion is positioned at the end of the holding portion on the side of the hollow portion.

[0095] (Appendix 2) a trowel tip portion in which a cavity portion is formed; a temperature detection unit located in the hollow portion and detecting the temperature of the iron tip; a holding portion that is inserted into the hollow portion and holds the temperature detection portion at a tip end thereof; Equipped with The area Sd of the holding portion in contact with the inner surface of the hollow portion when the holding portion is inserted into the hollow portion and the area Sg of the inner surface of the hollow portion between the tip of the holding portion and an opposing portion of the hollow portion that faces the tip of the hollow portion satisfy the following relational expression: Soldering iron. 0≦Sg≦0.25Sd The holding portion holds the temperature detection portion so that the temperature detection portion is positioned at the end of the holding portion on the side of the hollow portion.

[0096] (Appendix 3) 3. The soldering iron according to claim 1, wherein the thermal conductivity of the holding portion is equal to or greater than the thermal conductivity of the soldering tip portion.

[0097] (Appendix 4) the holding portion has an accommodation hole formed therein for accommodating the temperature detection portion, The cross section of the accommodation hole is smaller than the cross section of the temperature detection portion, The temperature detection unit is press-fitted into the accommodation hole. A soldering iron according to any one of Supplementary Notes 1 to 3.

[0098] (Appendix 5) the cavity includes a cylindrical first portion; the holding portion includes a cylindrical second portion; a cross-sectional size of the first portion is smaller than a cross-sectional size of the second portion; the second portion is press-fit into the first portion; A soldering iron according to any one of Supplementary Notes 1 to 4. [Explanation of symbols]

[0099] 1A soldering iron 20 Heater wire 4b Second storage section 10A heater 11 Bobbin 33 Temperature detection unit 34 Thermal Conductors

Claims

1. a trowel tip portion in which a cavity portion is formed; a temperature detection unit located in the hollow portion and detecting the temperature of the iron tip; a holding portion that is inserted into the hollow portion and holds the temperature detection portion at a tip end thereof; Equipped with The depth Ld of the hollow portion and the distance Lg between the tip end of the inserted holding portion and an opposing portion of the hollow portion opposing the tip end satisfy the following relational expression: Soldering iron. 0≦Lg≦0.25Ld

2. a trowel tip portion in which a cavity portion is formed; a temperature detection unit located in the hollow portion and detecting the temperature of the iron tip; a holding portion that is inserted into the hollow portion and holds the temperature detection portion at a tip end thereof; Equipped with The area Sd of the holding portion in contact with the inner surface of the hollow portion when the holding portion is inserted into the hollow portion and the area Sg of the inner surface of the hollow portion between the tip of the holding portion and an opposing portion of the hollow portion that faces the tip of the hollow portion satisfy the following relational expression: Soldering iron. 0≦Sg≦0.25Sd

3. 3. The soldering iron according to claim 1, wherein the thermal conductivity of the holding portion is within a predetermined range that includes the thermal conductivity of the tip portion.

4. the holding portion is formed with a housing portion for housing the temperature detection portion, a cross section of the accommodation portion being smaller than a cross section of the temperature detection portion; The temperature detection unit is press-fitted into the housing unit. The soldering iron according to claim 1 or 2.

5. the cavity includes a cylindrical first portion; the holding portion includes a cylindrical second portion; a cross-sectional size of the first portion smaller than a cross-sectional size of the second portion; the second portion is press-fit into the first portion; The soldering iron according to claim 1 or 2.

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