JP2005081373A - Temperature control device for soldering iron, and its control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make a temperature control device for soldering irons, wherein the temperatures of a plurality of iron tips are controlled in an integrated state, small in size and light in weight while performing the control of feeding heating pulses to heating parts. <P>SOLUTION: The temperature control device 1 for the soldering irons, wherein the temperatures of the plurality of iron tips 24a and 24b are controlled in an integrated state, is provided with: a heating pulse generating part 4; heating parts 40a and 40b receiving heating pulses and heating the trowel tips 24a and 24b; temperature sensors 52a and 52b; a control part 10 assigning the heating pulses to each heating part 40a and 40b by piece units; and switching parts 6a and 6b switching the on/off of the feed of the heating pulses to the heating parts 40a and 40b. In the control part 10, with the period in the prescribed number of the heating pulses as a control cycle, and the temperature control cycles are assigned to the heating parts 40a and 40b in prescribed order, and in the assigned temperature control cycles, the number of the heating pulses to be fed to the heating parts are decided in accordance with the temperature of each iron tip. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a temperature control device for a soldering iron and a control method thereof, and more particularly, to a temperature control device for a soldering iron that integrally controls the temperatures of a plurality of tips and a control method thereof.

  As a method of controlling the temperature of the soldering iron tip, there is known a method of feedback-controlling the heater on-time while detecting the temperature of the tip with a temperature sensor or the like. And what used the pulse which carried out the full wave rectification of alternating current as a reference | standard unit of heater ON time is known (for example, refer patent document 1).

  The apparatus disclosed in Patent Document 1 rectifies alternating current as a full wave to form a heating pulse and supplies it to the tip. Further, an integral multiple (M) of the heating pulses is set as a constant temperature control cycle. Then, the temperature is adjusted by increasing or decreasing the number of heating pulses supplied (N, N ≦ M) in the temperature control cycle according to the fed tip temperature.

  According to the apparatus disclosed in Patent Document 1, since power is supplied to the tip in units of the number of heating pulses, the voltage change at the start of supply gradually rises from zero volts (sine curve after full-wave rectification). It becomes. For this reason, it is possible to reliably prevent the high-frequency pulse generated when the voltage of the heating pulse rises from zero to the on state at once.

  By the way, an ordinary soldering iron is provided with one tip, so that the control target is only that tip, but a plurality of tips are controlled together by a single control device (hereinafter referred to as “tip”). In some cases, integrated control) is desirable because the entire apparatus can be reduced in size and cost. For example, a device equipped with a plurality of tips per unit, such as a tweezer type electric component attaching / detaching device, is suitable for integrated control. The tweezers type electric component attaching / detaching device has a pair of legs, and two tips are provided at the tips of the legs, and the legs are opened and closed like tweezers. The parts are sandwiched or released (for example, see Patent Document 2).

  As another form, when a plurality of soldering irons (for example, ones having different tip shapes) are frequently replaced in the same work place, these soldering irons are integrated and integrated by a single control device. It is suitable to control.

  FIG. 7 shows a prior art example in which a technique such as that disclosed in Patent Document 1 is applied when integrated control of a plurality of tips is performed. (A) is a schematic block diagram of control, (b) is a time chart of a heating pulse assigned to each heating unit.

  In the configuration of FIG. 7A, after the electric power supplied from the AC power supply 2 is converted into a predetermined voltage by the transformer 203, the heating pulse generator 204 performs full-wave rectification to obtain a heating pulse. The heating pulse is guided to the switching unit 206, and is branched to the reference pulse generating unit 205. The reference pulse generator 205 generates a signal (reference pulse) that can count the number of pulses in synchronization with the heating pulse and inputs the signal to the CPU 210.

  The CPU 210 sets M (M = 10 in this example) reference pulses as one unit of control time, and sets N (0 ≦ N ≦ M) as the heater on time. The CPU 210 outputs a switch-on signal (control signal) to the switching unit 206 for the set heater-on time. The switching unit 206 guides the heating pulse to the heating units 240a and 240b corresponding to the plurality of (two in the drawing) tips 224a and 224b based on the control signal for the heater ON time. As a result, each tip is heated and the temperature rises. The temperatures of the tips are detected by the temperature sensors 252a and 252b, and the detection signals are input to the CPU 210 via the amplification units 207a and 207b and the voltage adjustment units 208a and 208b. CPU 210 determines the next heating pulse number N based on the detection signal. That is, feedback control is performed to increase the number N of heating pulses when the temperature is lower than the target temperature and to decrease the number N of heating pulses when the temperature is higher.

  FIG. 7B is a time chart of voltages applied to the heating units 240a and 240b by the above control. The horizontal axis represents time, and the vertical axis represents voltage. The upper part shows a time chart 249a corresponding to the heating part 240a, and the lower part shows a time chart 249b corresponding to the heating part 240b. In either case, the temperature control cycle T201 is set at M = 10. In the state shown in the figure, the number N201 of the heating pulses 260 supplied in the temperature control cycle T201 is 6 in both the time charts 249a and 249b. The temperature control of the tips 224a and 224b is performed by increasing or decreasing the number N of heating pulses for each temperature control cycle. For example, when the temperature of the tips 224a and 224b is lower than the target temperature, the heating pulse number N is increased in the next temperature control cycle T202, and conversely when it is higher, the heating pulse number N is decreased.

The control shown in FIG. 7A has a simple circuit configuration, but the number of heating pulses supplied to each heating unit is the same as shown in FIG. 7B. In order to control this individually, it is also known that a switching unit 206 is provided for each heating unit, and an individual heating pulse number N is set and supplied.
JP 2001-62562 A JP 07-116835 A

  According to the above prior art, in the temperature control cycle T (total number of pulses = M), all the tips are simultaneously heated by the N heating pulses 260 from the beginning, and the remaining (MN) pulses are used. During the corresponding time, all the tips are not heated. Therefore, the power consumption during heating is twice the number of tips (twice in the above-mentioned conventional example) with respect to a soldering iron having only one tip. Naturally, it is necessary to secure a large capacity for the transformer 203 accordingly, and it is difficult to avoid an increase in size and weight of the apparatus. This situation is the same in the case where the number N of individual heating pulses is set and supplied for each iron tip. If the number of heating pulses, which is less, is N ′, N ′ number of heating pulses are applied to each iron. Since it is necessary to supply them simultaneously, it is inevitable to increase the capacity of the transformer 203.

  In view of the above problems, the present invention provides a temperature control apparatus and control method for a soldering iron that integrates and controls the temperatures of a plurality of tips, and supplies the heating parts of each tip while increasing or decreasing the number of heating pulses. It is an object to reduce the size and weight of the apparatus while performing control.

  In order to solve the above-mentioned problem, the invention of claim 1 is a temperature control device for a soldering iron that integrally controls the temperature of a plurality of tips, and includes a heating pulse generator that generates a heating pulse, and the heating pulse. Each heating unit for receiving and heating each of the tips; a temperature sensor for detecting the temperature of each of the tips; and a control unit for assigning the heating pulse to each heating unit in units of the number of pulses; And a switching unit that switches the presence or absence of the supply of the heating pulse to each of the heating units according to a control signal from the control unit, and the control unit sets a period corresponding to a predetermined number of the heating pulses to a temperature control cycle. And assigning the temperature control cycle to each heating unit in a predetermined order, and in the temperature control cycle corresponding to the assigned heating unit, the tip heated by the heating unit Based on the detection signal of the temperature sensor to respond, with successively determined number heating pulse to be supplied to the heating unit, a control signal which becomes the supply command, characterized in that issuing a switching unit corresponding to the heating unit.

  According to this configuration, the heating pulse is supplied to each heating unit in units of number, and the tip temperature is increased. The number of heating pulses to be supplied can be increased or decreased according to the temperature of the tip by switching at the switching unit. That is, when the tip temperature detected by the temperature sensor is lower than the set temperature, the number of heating pulses is increased, and when the temperature is higher, the number of heating pulses is decreased to bring the temperature of each tip closer to the set temperature. It can be maintained and good soldering can be performed.

  Furthermore, according to the configuration of the present invention, the temperature control cycle is assigned to each heating unit in a predetermined order, and at a certain moment, the heating pulse is supplied only to the heating unit to which the temperature control cycle is assigned. For example, if the temperature control cycle is set so as to be assigned to each heating unit without overlap (complete non-overlap), a heating pulse is not supplied to a plurality of heating units at the same time, and at a certain moment, at most one heating unit A heating pulse will be supplied. In addition, if it is set so as to be partially and not overlapped (partially non-overlapping), the heating pulses are not supplied to all the heating parts simultaneously, and the total amount of heating pulses supplied at a certain moment is completely overlapped. Less than the case of allocation (complete duplication, corresponding to the prior art).

  When allocation is performed in a completely non-overlapping or partially non-overlapping manner, the maximum supply energy (time average) per one tip is lowered with respect to the completely overlapping allocation. This is because continuous heating is possible with complete overlap, whereas intermittent heating is inevitably caused with complete non-overlap or partial non-overlap. However, in the normal usage form of the soldering iron, the tip is heated with the maximum energy until it is raised to the set temperature near the start of use, and thereafter (hereinafter referred to as the normal use range) is soldered. Heating to compensate for heat consumption due to heat and heat radiation to the air (about 30 to 50% of the maximum) is sufficient. When complete non-overlapping or partial non-overlapping allocation is performed in such a normal range, energy supply timing can be distributed for each tip without reducing supply energy. Therefore, the energy supply amount in the heating pulse generator can be leveled in time, and the instantaneous maximum supply amount can be reduced.

  Note that the heating capacity (for example, heater capacity) of each heating unit may be lowered while assigning a complete overlap if only to reduce the instantaneous maximum supply amount in the heating pulse generation unit. However, if the heating capacity is reduced, the tip temperature will not rise to the set temperature at the start of use, or the number of parts will increase by setting a different tip (including the heater structure) with a different heating capacity. Problem arises. According to the present invention, since the heating capability of the heating unit can be made equivalent to that of the conventional product, the instantaneous maximum supply amount in the heating pulse generating unit can be reduced without causing such a problem.

  Further, in the above configuration, the heating pulse generator is configured by a full-wave rectifier circuit and an additional diode connected to the full-wave rectifier circuit, and at least one point in each temperature control cycle has zero volts or more for a predetermined period. The heating pulse may be generated so as to have a period, and the control unit may receive signals from the temperature sensors during the zero volt period.

  In this way, the control unit can receive the signal from the temperature sensor using the zero volt period, so that it is not necessary to interrupt the heating pulse when receiving the signal. Therefore, the circuit configuration and control contents can be simplified.

  By the way, as described above, when complete non-overlapping or partial non-overlapping allocation is performed, the margin of energy supply to each heating unit is reduced, so there is a concern that the follow-up of temperature control may be reduced. Therefore, each of the heating units and the temperature sensor are arranged in a state where they are separated from each other in the longitudinal direction of the tip, and the temperature sensor is disposed on the tip side of the heating unit. 3) This is effective.

  In this case, since the heating unit and the temperature sensor are provided separately in the longitudinal direction, the temperature sensor is less susceptible to the temperature of the heating unit, and can detect the tip temperature with higher accuracy. it can. For this reason, a temperature drop can be detected quickly, and supply energy can be increased immediately, so that followability of temperature control can be enhanced.

  In the above configuration, it is also effective that the control unit assigns the temperature control cycle to a plurality of heating units in an overlapping manner when the tip is in a predetermined low temperature state (Claim 4).

  In this way, when the tip is in a predetermined low temperature state, the temperature increase rate of the tip can be increased by assigning complete or partial non-overlap of the temperature control cycle. This is a control giving priority to the temperature rise of the tip, and is a control in a direction contrary to the target control of claim 1. However, the influence can be kept to a minimum by appropriately setting a predetermined low temperature state which is a precondition for performing such control.

  For example, if the predetermined low temperature state is a state until reaching the set temperature at the start of use, the period is about several seconds to several tens of seconds, which is extremely short with respect to the total time of the soldering work performed industrially. It's time. In such a case, while reducing the instantaneous maximum supply amount in the heating pulse generator, the rated capacity of the transformer when the supply capacity is determined based on the transformer capacity, for example, only in a predetermined low temperature state. It is possible to apply the above power).

  As a specific configuration of the iron tip, the iron tip may be provided at each tip portion of a plurality of soldering irons (Claim 5). The electrical component attaching / detaching device is configured to sandwich or release the electrical component with the tip by opening and closing the leg portion. (Claim 6. A so-called tweezers type electric component attaching / detaching device).

  According to a seventh aspect of the present invention, in the temperature control method for a soldering iron in which the temperatures of a plurality of tips are integrated and controlled, a heating pulse is generated and the heating pulse is supplied to a plurality of heating units in units of the number of pulses. In addition, each of the heating units heats the corresponding tip by the supplied heating pulse, and a period corresponding to a predetermined number of the heating pulses is set as a temperature control cycle, and the temperature control cycle is set to a predetermined value. In the temperature control cycle corresponding to the assigned heating unit, the number of heating pulses supplied to the heating unit is sequentially determined according to the temperature of the tip heated by the heating unit. It is determined and supplied.

  According to this method, as in the case of claim 1, by performing the non-overlapping or partial non-overlapping assignment, it is possible to distribute the energy supply timing for each heating unit without reducing the supply energy. . Therefore, the energy supply amount in the heating pulse generator can be leveled in time, and the instantaneous maximum supply amount can be reduced. That is, the apparatus can be reduced in size and weight.

  According to the soldering iron temperature control device and the control method thereof of the present invention, the size and weight of the device can be reduced (for example, by reducing the transformer capacity) while controlling the supply to each tip while increasing or decreasing the number of heating pulses. ). Moreover, since it can be realized without reducing the heating capacity (for example, heater capacity) of the heating unit, it is prevented that the temperature of the tip is hindered. In addition, since it is not necessary to separately set heating units having different heating capacities, the structure of the heating unit can be made common and productivity can be increased. Furthermore, by sharing the structure of the heating unit, the tip is shared between the case where one tip is controlled independently and the case where a plurality of tips are integrated and controlled by a single control device. Can do. Alternatively, in a tweezer type electrical component attaching / detaching device, etc., the main body structure including the heating unit is made common, and the setting that is close to non-overlapping assignment for users who prefer the miniaturization and weight reduction of the power supply / control unit ( The control device can be made smaller and lighter), and for a user who prefers the temperature rise speed preferentially, a control device with a setting close to a completely overlapping allocation (a setting close to a conventional control device) is provided. You can also choose to provide.

  The best mode for carrying out the invention will be described below with reference to the accompanying drawings.

  FIG. 1 is a front view of a tweezer-type handheld electric component attaching / detaching device having a tip to be controlled in the embodiment of the present invention. The illustrated electric component attaching / detaching device 21 is in a normal position where the leg 23 is biased toward the open leg when free (when no operating force is applied), and when the leg 23 is free when the leg 23 is closed. It is configured to be able to switch the state of the biased reverse position, and FIG. 1 shows the state of the normal position when it is free.

  The electric component attaching / detaching device 21 has a thin housing 22 having a shape that can be easily grasped by a palm. A sleeve 26 for supporting a leg portion 23 described later is provided near the front end (left side of the drawing) of the housing 22. Specifically, a movable sleeve 26a is provided on the upper side, and a fixed sleeve 26b is provided on the lower side. The movable sleeve 26 a is movably supported by the housing 22 so as to be rotatable about the movable leg support shaft 27. The movable sleeve 26a has a recess formed on the upper surface (the upper side in the figure) where an operator can easily apply an operating force. The fixing sleeve 26 b is fixed to the housing 22.

  A pair of leg portions 23 extend from the distal end side of the sleeve 26 toward the distal end side. Specifically, the movable leg portion 23a extends from the movable sleeve 26a, and the fixed leg portion 23b extends from the fixed sleeve 26b. A tip 24 is provided at the tip of the leg 23. Specifically, a movable leg tip 24a is provided at the tip of the movable leg 23a, and a fixed leg tip 24b is provided at the tip of the fixed leg 23b. The tip 24 is a part for directly sandwiching the electronic component and a part for melting the solder. A heating unit is built in the vicinity of the proximal end portion of the tip 24 as described later, and heat generated in the heating unit is conducted to the tip 24.

  At the rear end of the housing 22, power (heating pulse) is supplied from the switching unit 6 of the soldering iron temperature control device (see FIG. 3, hereinafter referred to as the temperature control device 1), or the amplification unit of the temperature control device 1. 7 is extended with a cord 31 for supplying a sensor signal. Due to the heating pulse supplied via the cord 31, the heating part built in the leg part 23 generates heat (details of the heating part will be described later).

  A coil spring and a link mechanism (not shown) are built in the housing 22. An urging state switching lever 28 is provided near the rear end of the housing 22 on the front side in the drawing. The urging state of the leg portion 23 by the coil spring is switched by switching of the urging state switching lever 28. That is, by rotating the urging state switching lever 28 around the switching lever support shaft 29, the urging state when the leg portion 23 is free is switched between the open leg side (normal position) and the closed leg side (reverse position). be able to. A switching lever knob 30 is provided at the tip of the urging state switching lever 28 for the operator to rotate it. The switching lever knob 30 indicates the current position (energized state) by pointing to the mark “N” (representing a normal position) or “R” (representing a reverse position) displayed on the housing 22. To do.

  FIG. 2 is an enlarged cross-sectional view of the vicinity of the movable leg tip 24a. The movable leg tip 24a is made of a metal mainly composed of copper or silver, and is inserted into the tip of a stainless steel protective pipe 38a which is a main body of the movable leg 23a.

  A heating unit 40a is provided in the inside from the vicinity of the front end of the protective pipe 38a to the vicinity of the rear end of the movable leg tip 24a. The heating unit 40a is a part that generates heat by electric power (heating pulse). A heater core 43a having a tip embedded in the rear end of the movable leg tip 24a is disposed at the center of the heating unit 40a. The heater core 43a is made of a material having high thermal conductivity such as copper. The exposed portion of the heater core 43a is covered with a heater core cover 42a, and a heating wire 41a connected to the heater lead wire 45a is wound around the outer periphery of the heater core 43a in a coil shape. The heat generated in the heating wire 41a is conducted to the heater core 43a inside the coil via the heater core cover 42a, and further conducted from the heater core 43a to the movable leg tip 24a mainly in the longitudinal direction of the protective pipe 38a. The As a result, the movable leg tip 24a is heated to around 350 to 400 ° C. and acts as a kind of soldering iron.

  A sensor unit 50a is provided near the inner center of the movable leg tip 24a and on the tip side of the heating unit 40a. The sensor unit 50a is a part that detects the tip temperature of the movable leg tip 24a. A temperature sensor 52a is provided at a tip portion of the sensor unit 50a and in contact with the movable leg tip 24a. A sensor insulating tube 53 is provided behind the sensor insulating tube 53. The sensor insulating tube 53a forms a passage for the sensor lead wire 51a. In addition, the distance between the heating unit 40a and the temperature sensor 52a is maintained at a certain distance, and heat is directly conducted from the heating unit 40a to the temperature sensor 52a. Is prevented as much as possible.

  The sensor lead wire 51a and the heater lead wire 45a are covered with the heater insulating tube 44a, the sensor lead insulating tube 46a, etc., and connected to an electrode (not shown) in the movable sleeve 26a via the inside of the protective pipe 38a. Has been.

  The temperature sensor 52a is configured to detect the temperature with a thermocouple. Specifically, the heater lead wire 45a and the heating wire 41a are made of an iron-chromium alloy (for example, Kanthal wire manufactured by Kanthal Corporation), and the sensor lead wire 51a is made of a nickel wire. And the welding point which carried out argon welding of these is the temperature sensor 52a. Therefore, an electromotive force due to the Seebeck effect is generated according to the temperature difference between the temperature of the temperature sensor 52a and the temperature of the proximal end portion of the sensor lead wire 51a. The temperature of the movable leg tip 24a can be detected by measuring the electromotive force (voltage). The temperature of the base end portion of the sensor lead wire 51a is measured by a thermistor 55a (see FIG. 3) provided in the movable sleeve 26a.

  Since the fixed leg portion 23b is vertically symmetrical with the movable leg portion 23a, detailed description thereof will be omitted. As corresponding members, a fixed leg tip 24b, a heating unit 40b, a temperature sensor 52b, a sensor insulating tube 53b, a thermistor 55b, and the like are provided.

  FIG. 3 is a schematic control block diagram of the temperature control apparatus 1. The temperature control device 1 controls the movable leg tip 24a and the fixed leg tip 24b so as to maintain a predetermined temperature. Constituent elements corresponding to the movable leg tip 24a and the fixed leg tip 24b are the transformer 3, the heating pulse generator 4, the reference pulse generator 5, the CPU 10, the EEPROM 11, the key input unit 12, and the display unit. 13 is provided. Further, the switching unit 6 (6a, 6b), the amplifying unit 7 (7a, 7b), and the heating unit 40 (40a, 40b) are components corresponding to the movable leg tip 24a and the fixed leg tip 24b, respectively. The temperature sensor 52 (52a, 52b) and the thermistor 55 (55a, 55b) are provided. The internal circuits of the switching unit 6b and the amplifying unit 7b are the same as the internal circuits of the switching unit 6a and the amplifying unit 7a, respectively.

  An AC power source 2 is used as a power source for the temperature control device 1. The AC power source 2 is a general commercial AC power source of 100V (or 120V). The transformer 3 steps down the primary voltage input from the AC power supply 2 to a secondary voltage of 24V.

  A heating pulse generator 4 is connected to the circuit downstream side of the transformer 3. The heating pulse generator 4 includes a full-wave rectifier circuit 410 and a diode 415 added thereto. The full-wave rectifier circuit 410 is a circuit that full-wave rectifies the secondary AC voltage (24 V) from the transformer 3 and is composed of four diodes 411, 412, 413, and 414 that form a so-called bridge circuit. Alternating current is converted into direct current by full-wave rectification, and its voltage characteristic becomes a pulse waveform as if the negative side of the alternating current sine curve is folded back to the positive side (see FIG. 4). Since the period of this pulse is a half of one cycle period of the AC power supply 2, it is 10 ms when the frequency f of the AC power supply 2 is 50 Hz, and 8.33 ms when it is 60 Hz.

Since the diode 415 is added to the full-wave rectifier circuit 410, the current path in the heating pulse generator 4 is diode 411 → load → diode 415 → diode 414 or diode 412 → load → diode 415 → diode 413. In either case, a voltage drop corresponding to three diodes occurs during rectification. Accordingly, if the voltage drop margin per diode is V _F , the voltage after rectification is actually zero volts due to the voltage drop during the period when the voltage drop is 3 × V _F or less without considering the voltage drop. Thus, the heating pulse generator 4 outputs the heating pulse 60 (see FIG. 4) in which the zero volt period τ is formed between the pulses. Incidentally, a relationship of the following equation to zero volts period τ and the voltage drop margin V _F.

SQR (2) × 24 × sin (π × f × τ) = 3 × V _F
In this embodiment, V _F ≈0.9 V, so that τ≈0.5 ms when f = 50 Hz, and τ≈0.42 ms when f = 60 Hz.

  The circuit downstream side of the heating pulse generator 4 branches, one of which is connected to the reference pulse generator 5 and the other is connected to the switching unit 6. The reference pulse generator 5 is composed of a comparator (comparator) 501 and the like, and by comparing the voltage of the heating pulse 60 generated by the heating pulse generator 4 with a reference voltage (about 0.6 V), a zero cross pulse is generated. Is generated. This zero cross pulse is a pulse signal that turns on when the voltage of the heating pulse 60 is lower than the reference voltage (near the boundary of the heating pulse 60), and turns off when the voltage is not, and is synchronized with the heating pulse 60. And sent to the CPU 10 as a reference pulse for control.

  The CPU 10 is a central processing unit having a built-in ROM or the like that stores a control program. An EEPROM 11, a key input unit 12, and a display unit 13 are connected to the CPU 10. The EEPROM 11 is an electrically erasable and rewritable memory, stores information such as the set temperature of the tip 24, and inputs / outputs the stored contents to / from the CPU 10 in response to a request from the CPU 10. The contents stored in the EEPROM 11 are retained even after the power is turned off. The key input unit 12 receives a condition setting (such as a set temperature of the tip 24) from the operator and inputs it to the CPU 10. The display unit 13 receives predetermined control information (such as the current temperature of the tip 24) from the CPU 10 and displays it.

  The CPU 10 receives the reference pulse generated by the reference pulse generator 5 and uses it as a reference for control timing. Specifically, the CPU 10 issues a control signal to the switching unit 6 (details will be described later), and performs control to assign the heating pulse 60 to the heating unit 40a and the heating unit 40b, but the on / off switching timing is a reference pulse. Synchronize with. Since the reference pulse is synchronized with the heating pulse 60, the on / off switching timing is eventually synchronized with the heating pulse 60. That is, the heating pulse 60 is turned on / off at the break point of the heating pulse 60, so the heating pulse 60 is assigned to the heating unit 40a and the heating unit 40b in units of the number of pulses.

  The switching unit 6 includes a transistor 601, a FET 602 (field effect transistor), a capacitor 603, and the like. The heating pulse generator 4 is connected to the circuit upstream side of the switching unit 6 as described above. A heating unit 40 is connected to the downstream side of the circuit. Further, it is also connected to the CPU 10 for receiving a control signal. The switching unit 6 switches whether to supply the heating pulse 60 from the heating pulse generation unit 4 to the heating unit 40 according to a control signal from the CPU 10. That is, the heating pulse 60 is supplied when an on-command control signal (for example, a current greater than or equal to a predetermined value) is issued from the CPU 10, and heating is performed when an off-command control signal (for example, zero or a current less than a predetermined value) is generated. Pulse 60 is not supplied.

  The heating unit 40 (40a, 40b), the temperature sensor 52 (52a, 52b), and the thermistor 55 (55a, 55b) are connected to the circuit downstream side of the switching unit 6. As described above, the heating unit 40 that has received the heating pulse 60 generates heat and heats the tip 24. The temperature is detected by the temperature sensor 52. Specifically, an electromotive force (voltage) that varies according to temperature is output to the amplifying unit 7.

  The amplification unit 7 is connected to the circuit downstream side of the heating unit 40 and the thermistor 55. The amplification unit 7 includes a first amplifier 701, a second amplifier 702, and the like. When the switching unit 6 is in the ON state, a voltage obtained by superimposing the heating pulse 60 and the sensor voltage is input to the first amplifier 701, and this is amplified. On the other hand, when the switching unit 6 is in the OFF state, only the sensor voltage is input to the first amplifier 701 and amplifies it. Even when the switching unit 6 is in the ON state, when the voltage of the heating pulse 60 is zero (zero volt period τ), only the sensor voltage is actually input to the first amplifier 701.

  The output from the first amplifier 701 and the output from the thermistor 55 are added to the second amplifier 702 and input. Therefore, when the switching unit 6 is in the OFF state or in the zero volt period τ, the output from the second amplifier 702 is an amplified voltage corresponding to the temperature of the tip 24, which is input to the CPU 10. The

  Next, operations of the electric component attaching / detaching device 21 and the temperature control device 1 will be described. In using the electric component attaching / detaching device 21, the operator first selects the normal position N or the reverse position R. The selection may be made arbitrarily by the operator. Generally, the normal position N is suitable for removing an electronic component soldered to the board, and the reverse position R is suitable for soldering an electronic part to the board. .

  When the switching lever knob 30 is set to the N position and the normal position N is selected, the movable sleeve 26a is urged to the open leg side by the internal spring (state of FIG. 1). The operator can close the leg portion 23 by pressing a concave portion provided in front of the upper portion of the movable sleeve 26a, and can hold the electronic component. Since the temperature of the iron tip 24 is controlled by the temperature control device 1 so as to be close to the set temperature, the operator melts the solder with the iron tip 24 while holding the electronic component soldered to the substrate, for example. By doing so, the electronic component can be easily removed from the substrate.

  On the other hand, when the reverse lever R is selected by setting the switching lever knob 30 to the R position, the biasing direction of the internal spring is switched, and the movable sleeve 26a is biased toward the closed leg. The operator can open the leg portion 23 by pressing a concave portion provided on the upper rear side of the movable sleeve 26a, and can hold the electronic component. After clamping, even if the operator releases his hand from the movable sleeve 26a, the tip 24 continues to clamp the electronic component by the biasing force. Since the temperature of the tip 24 is controlled by the temperature control device 1 so as to be close to the set temperature, the operator sets, for example, the position where the board is attached while holding the electronic component, and directly uses the tip 24. Soldering can be performed. At that time, since the electronic component is held by the tip 24 even if the hand is released from the movable sleeve 26a, the operator can set the electronic component while holding the housing 22 lightly without applying excessive force. It ’s fine. Therefore, delicate position adjustment is facilitated.

  The temperature control of the tip 24 by the temperature control device 1 is performed as follows. The power supplied from the AC power supply 2 is first stepped down to 24V by the transformer 3. Subsequently, the alternating current is full-wave rectified by the heating pulse generator 4 to generate a heating pulse 60 having a zero volt period τ. The heating pulse 60 is guided to the switching unit 6 and to the reference pulse generating unit 5, and the reference pulse generating unit 5 generates a reference pulse synchronized with the heating pulse 60. The reference pulse is guided to the CPU 10.

  The CPU 10 uses a program read from the built-in ROM, and a control signal (on command or off command) synchronized with the reference pulse so that the temperature of the tip 24 maintains the set temperature input from the key input unit 12. To the switching unit 6. The switching unit 6 supplies the heating pulse 60 guided from the heating pulse generation unit 4 to the heating unit 40 only when receiving an ON command control signal.

  In FIG. 4, the time chart of the heating pulse 60 allocated to the heating part 40 is shown. The upper part shows a time chart 49a corresponding to the heating part 40a, and the lower part shows a time chart 49b corresponding to the heating part 40b. The horizontal axis represents time, and the vertical axis represents voltage.

The CPU 10 collectively sets a period corresponding to five heating pulses 60 as a temperature control cycle T (the number M of heating pulses 60 = 5). Then, the temperature control cycle T (T ₁ , T ₂ , T ₃ ,...) Is set as one unit, and this is alternately allocated to the heating unit 40a and the heating unit 40b. That is, as shown in the time charts 49a and 49b, the temperature control cycles T ₁ , T ₃ , T ₅ ,... Are assigned to the heating unit 40a, and the temperature control cycles T ₂ , T ₄ ,.・ Is assigned.

Focusing on the temperature control cycle T ₁ of the time chart 49a, the number N ₁ of heating pulses 60 that can be supplied during this period is 5 at the maximum. In practice, however, N ₁ = 3 (two heating pulses 60 that are not actually supplied are indicated by broken lines). CPU10, compared switching unit 6a corresponding to the movable leg tip 24a, emits a control signal only on command period equivalent from an initial temperature control cycle T ₁ to 3 pieces of the heating pulse 60. The value of N ₁ is not fixed to N ₁ = 3, and can vary in the range of 0 to 5, it is sequentially determined to be optimum values according to the temperature of the movable leg tip 24a (The method for determining the supply number N will be described later).

In the temperature control cycle T _1, as shown in the time chart 49b, heating pulse 60 is not supplied to the heating portion 40b. CPU10 whereas switching unit 6b corresponding to the fixed leg tip 24b, issues a normally-off command for the duration of the temperature control cycle T _1.

In the subsequent temperature control cycle T ₂ , the supply destination of the heating pulse 60 is reversed, and N ₂ = 3 heating pulses 60 are supplied only to the heating unit 40 _b . In this way, the temperature control cycles T ₃ , T ₄ , T ₅ ,... Are alternately assigned to the heating units 40a, 40b, and the necessary number of heating pulses 60 are supplied to both, thereby moving the movable leg tip. The temperature of 24a and the fixed leg tip 24b is maintained.

In the present embodiment, a period corresponding to one heating pulse 60 is provided between the temperature control cycles T ₂ and T _3, and an OFF period in which the heating pulse 60 is not assigned to any one is provided. When the OFF period is provided, for example, when the first heating pulse 60 of the temperature control cycle T ₁ is generated from the positive voltage side waveform before rectification, the first heating pulse 60 of the next temperature control cycle T ₃ is provided. Is generated from the negative voltage side waveform before rectification. By providing such an OFF period once per two cycles of the temperature control cycle T, the usage frequency of the heating pulse 60 generated from the positive voltage side waveform and the usage frequency of the heating pulse 60 generated from the negative voltage side waveform And can be leveled. Therefore, even if the waveform before the rectification of the AC power supply 2 is not positive / negative symmetric, the influence can be offset and the control accuracy can be improved.

A zero volt period τ is provided at the boundary of each heating pulse 60. The Figure 4 shows a zero volt periods τ (τ ₁ ~τ ₅₎ at a temperature control cycle T _1, is the same temperature control cycle T ₂ later. The temperature of the movable leg tip 24a is detected using this zero volt period τ. As described above, in the zero volt period τ, only the voltage from the temperature sensor 52a is input to the amplifying unit 7a, amplified, and then input to the CPU 10. In the present embodiment, temperature detection is performed in the first zero volt period τ ₁ in the temperature control cycle T ₁ .

The detected temperature Temp of the movable leg tip 24a is converted into a display unit (° C. or the like) and displayed on the display unit 13. Further, the temperature Temp of the movable leg tip 24a is compared with the set temperature inputted from the key input unit 12 and stored in the EEPROM 11, and the supply number N ₃ of the next heating pulse 60 (temperature control cycle T ₃ ) is determined. It is determined. For example, when the temperature Temp is lower than the set temperature, N ₃ is increased more than N ₁ . The increment increases as the temperature difference increases. Conversely, when the temperature Temp is higher than the set temperature, N ₃ is decreased from N ₁ . The decrease increases as the temperature difference increases.

The same control is performed in the temperature control cycles T ₃ , T ₅ ,..., And the similar control is performed for the heating unit 40b in the temperature control cycles T ₂ , T ₄ ,.

  By performing the control as described above, the temperature of the tip 24 can be maintained near the set temperature, and good soldering can be performed. Further, since the temperature control cycle T is assigned to each of the tips without any overlap (completely non-overlapping assignment), the heating pulse 60 is not supplied to both tips at the same time. In other words, the instantaneous maximum supply amount in the heating pulse generator 4 is the same as the case where only one tip 24 is temperature controlled. In the conventional structure in which the heating pulses 60 are supplied simultaneously (assignment of complete overlap), the instantaneous maximum supply amount twice as much as that in the case of controlling the temperature of only one tip 24 is necessary. By making such a completely non-overlapping assignment, the capacity of the transformer 3 can be halved. Accordingly, the temperature control device 1 can be reduced in size and weight.

  Moreover, although the capacity of the transformer 3 is reduced, the energy (current and voltage) per pulse of the heating pulse 60 can be made the same as in the case of simultaneous supply. That is, the capacity of the transformer 3 can be reduced without reducing the heater capacity of the heating unit 40. Therefore, the structure of the leg part 23 and the structure of the heating part 40 can be made common with those used independently, and productivity can be improved.

  In addition, when such a completely non-overlapping assignment is performed, the maximum supply energy (time average) per tip decreases with respect to the completely overlapping assignment. This is because continuous heating is possible with complete overlap, whereas intermittent heating is inevitably required with complete non-overlap. However, in the normal range (the temperature of the tip 24 is sufficiently high and in the vicinity of the set temperature), the heating required for the tip 24 compensates for heat consumption due to soldering and heat radiation to the air. About heating (about 30 to 50% of the maximum time) may be sufficient. Therefore, it is not necessary to reduce the supply energy even if the non-overlapping assignment is performed.

  However, since the margin of energy supply to the heating unit 40 is reduced, there is a concern that the followability of temperature control may be reduced. In this embodiment, the follow-up performance of the temperature control is prevented by adopting the tip portion structure of the leg portion 23 as described above. That is, in order to improve the followability of temperature control, the heating unit 40 and the temperature sensor 52 are provided in a state where they are separated in the longitudinal direction by the sensor insulating tube 53, and the temperature sensor 52 is not easily affected by the heating unit 40. The temperature of the tip 24 can be detected with high accuracy. In the conventional general structure, the heating unit 40 and the temperature sensor 52 are provided close to each other. For example, in FIG. 2, the heating wire 41a is provided at a location where the sensor insulating tube 53a is provided. Therefore, although the heat generated in the heating wire 41a is directly transmitted to the outer movable leg tip 24a, the temperature sensor 52a is greatly affected. That is, the temperature sensor 52a receives the heat from the movable leg tip 24a and the heat from the heating wire 41a and detects all of it as heat received from the movable leg tip 24a. The temperature of the tip 24a tends to be recognized higher than the actual temperature. If the temperature of the movable leg tip 24a is recognized to be higher than the actual temperature, the required heat supply amount is estimated to be small and not sufficiently supplied. As a result, the temperature of the movable leg tip 24a is lowered and the temperature followability is lowered.

  FIG. 5 shows temperature characteristics of the tip 4 when the electric component attaching / detaching device 21 is used as a soldering iron and continuous soldering is performed. (A) is the tip structure of this embodiment, (b) is the tip structure of the conventional structure. All are the characteristics which performed the continuous soldering of 1 second space | interval, time (s) is shown on a horizontal axis, and temperature (degreeC) is shown on a vertical axis | shaft.

  In the characteristic 70 of FIG. 5A, the temperature is maintained at about 400 ° C., the period during which soldering is not performed, and the temperature is oscillated with a large amplitude, which is seen about 150 seconds to about 200 seconds after the start of heating. The period during which continuous soldering is performed. One vibration of temperature corresponds to one soldering. As shown in this figure, when soldering is performed, heat is supplied to the solder, so the temperature of the tip 4 temporarily decreases by about 100 to 150 ° C. However, this is detected by the temperature sensor 52, and the power supplied to the heating unit 40 (the number of heating pulses) is increased under the control of the temperature control device 1. As a result, the temperature of the tip 4 that has temporarily decreased rises in the return direction. When the soldering interval is about 3 seconds, the temperature completely returns to around 400 ° C., but in this test, the interval is 1 second. Therefore, the next soldering is performed in the middle of the recovery, and it starts to decrease again. In other words, a phenomenon of lowering the return temperature is observed due to the frequency of soldering exceeding the temperature followability, and the margin for reduction is about 50 ° C.

  On the other hand, in the temperature characteristic 270 of the conventional structure shown in FIG. 5B, a decrease in the return temperature is similarly observed in the test result under the same conditions. However, the drop is larger than the temperature characteristic 70 and is about 80 ° C. Moreover, the temperature amplitude is clearly smaller than the temperature characteristic 70. This is because, even if the temperature of the tip 24 is lowered, the detection accuracy is insufficient, and the control for increasing the supply energy is delayed. That is, the temperature followability is lower than the temperature characteristic 70.

  In this embodiment, the detection accuracy of the temperature sensor 52 is higher than that of the conventional structure, and a structure with high temperature followability is provided, so that temperature followability is not easily lowered even when complete non-overlapping assignment is performed.

  When the operation of soldering the electronic component or removing the soldered electronic component is completed and the operator turns off the power, the supply of the heating pulse 60 is stopped, and the temperature of the tip 24 decreases. Since the information such as the set temperature stored in the EEPROM 11 is retained even when the power is turned off, this time even if the operator does not input the set temperature again from the key input unit 12 when the power is turned on next time. And the same set temperature.

  Next, as a modification of the present embodiment, a case where the temperature control device 1 performs integrated control of the temperatures of the two soldering iron tips will be described. Also in this case, if the structure around the tip of each soldering iron is as shown in FIG. 2, the above control can be applied as it is. However, when a conventional general soldering iron is used, the temperature increase rate at the time of start-up (the state in which the temperature of the tip 24 is still significantly lower than the set temperature immediately after power-on) may be reduced. is there. Hereinafter, control suitable for such a case will be described.

  The control of the temperature control device 1 is roughly divided into a rising time and a normal range. Since the control in the normal range is the same as the above-described control, the description is omitted, and the description of the parts common to the control in the normal range is also omitted in the control at the time of start-up. Hereinafter, the control at the time of start-up will be described by focusing on the difference from the control in the normal range.

The control at the time of rising is different from the control in the normal range in that the CPU 10 assigns the heating pulse 60 to the heating units 40a and 40b in an overlapping manner. That is, at the time of start-up, the CPU 10 always transmits an ON command control signal to both the switching units 6a and 6b. In FIG. 6, the time chart of the heating pulse 60 allocated to the heating part 40 by such control is shown. As shown in the figure, at the time of start-up (until time Tw), the temperature control cycle T ₀ is assigned to the heating part 40a and the heating part 40b at the same time (completely overlapping assignment). The temperature control cycle T ₀ is set as a period (M = 11) corresponding to 11 heating pulses 60, and the maximum number of heating pulses 60 supplied during that period is 11 (N ₀ = 11). ing. Then, the assignment of the temperature control cycle T ₀ is repeated until the temperature of the tip 24 reaches a predetermined temperature (set temperature or a temperature close thereto), and the control at the time of start-up is terminated at the time Tw when the temperature reaches the predetermined temperature. Shift to control in the normal range.

  In this way, since the maximum energy is supplied to both the heating units 40a and 40b at the time of startup, the temperature increase rate of the tip 24 can be maximized.

  It should be noted that such control at the time of start-up can be considered to be limited (1-2 times / day) at the start of power-on in an industrial usage of a soldering iron. Also, the time is about several seconds to several tens of seconds per time. That is, it is a very short time with respect to the total time of a soldering operation. If it is this level, there is no problem even if the transformer 3 with a reduced capacity is used with a load exceeding the rating.

  As mentioned above, although one Embodiment concerning this invention was described, this invention is not limited to this, A various deformation | transformation is possible within a claim. For example, the electric component attaching / detaching device 21 can switch between the normal position and the reverse position. However, the electric component attaching / detaching device 21 may have only the normal position, that is, the device that is always biased to the open leg side. Further, as a control target of the temperature control device 1, the electrical component attaching / detaching device 21 is provided with three or more tips, and three or more soldering irons are connected in parallel to perform integrated control. Also good.

  In the present embodiment, an example of performing complete non-overlapping allocation or complete overlapping allocation has been shown. However, allocation that is partially non-overlapping may be performed as necessary. The assignment of complete non-overlap, complete overlap, and partial non-overlap may be set in appropriate combination according to the conditions.

  Although it is not always necessary to provide the zero volt period τ, it is desirable to provide the zero volt period τ and transmit the sensor signal during this period, because the circuit can be simplified. In the present embodiment, the zero volt period τ is provided at the breakpoints of all the heating pulses 60. However, at least one zero volt period τ may be provided during the temperature control cycle T and detected there. Further, the temperature detection may be performed a plurality of times within the temperature control cycle T.

It is a front view of the electrical component attaching / detaching device to be controlled by the temperature control device of the soldering iron. It is an expanded sectional view of the tip vicinity of the electric component attaching / detaching apparatus shown in FIG. It is a general | schematic control block diagram of the temperature control apparatus of a soldering iron. It is a time chart of the heating pulse allocated to each heating part. It is a temperature characteristic of the tip of an electric component attaching / detaching apparatus, (a) is that of the electric component attaching / detaching apparatus shown in FIG. 1, and (b) is that of a conventional structure product. It is a time chart of the heating pulse allocated to each heating part. (A) is a schematic control block diagram of the temperature control apparatus of the soldering iron in a prior art, (b) is a time chart of the heating pulse allocated to each heating part.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Temperature control apparatus of a soldering iron 4 Heating pulse generation part 6 Switching part 10 CPU (control part)
DESCRIPTION OF SYMBOLS 21 Electrical component attachment / detachment apparatus 23 Leg part 24 Tip 40 Heating part 52 Temperature sensor 60 Heating pulse 410 Full wave rectifier circuit 415 Diode (addition diode)
T Temperature control cycle τ Zero volt period

Claims (7)

In a soldering iron temperature control device that integrates and controls the temperature of multiple tips,
A heating pulse generator for generating a heating pulse;
Each heating unit that receives the heating pulse and heats each of the tips,
Each temperature sensor for detecting the temperature of each of the tips,
A controller that assigns the heating pulse to each heating unit in units of the number of pulses;
Each switching unit for switching the presence or absence of supply of the heating pulse to each heating unit by a control signal from the control unit,
The control unit sets a period corresponding to a predetermined number of the heating pulses as a temperature control cycle, assigns the temperature control cycle to the heating units in a predetermined order, and in the temperature control cycle corresponding to the allocated heating unit, Based on the detection signal of the temperature sensor corresponding to the tip heated by the heating unit, the number of heating pulses supplied to the heating unit is sequentially determined, and the control signal serving as the supply command corresponds to the heating unit. A temperature control device for a soldering iron, which is emitted to a switching unit. The heating pulse generator includes a full-wave rectifier circuit and an additional diode connected to the full-wave rectifier circuit, and has a zero volt period equal to or greater than a predetermined period in at least one place in each temperature control cycle. Generating the heating pulse,
The temperature control device for a soldering iron according to claim 1, wherein the controller receives signals from the temperature sensors during the zero volt period.   Each of the heating units and the temperature sensor are separated in the longitudinal direction of the tip, and the temperature sensor is disposed on the tip side of the heating unit. The temperature control apparatus of the soldering iron of Claim 1 or 2.   4. The control unit according to claim 1, wherein when the tip is in a predetermined low temperature state, the control unit assigns the temperature control cycle to a plurality of heating units in an overlapping manner. 5. Soldering iron temperature control device.   The temperature control device for a soldering iron according to any one of claims 1 to 4, wherein the iron tip is provided at each tip of a plurality of soldering irons. The tip is provided at each tip of a pair of legs included in the electrical component attaching / detaching device,
5. The electrical component attaching / detaching device is configured to sandwich or release the electrical component with the tip by opening and closing the leg portion. 5. Soldering iron temperature control device. In the temperature control method of the soldering iron that integrates and controls the temperature of multiple tips,
Generate a heating pulse,
The heating pulse is supplied to a plurality of heating units in units of the number of pulses,
Each of the heating units heats the corresponding tip with the supplied heating pulse, and
A period of a predetermined number of the heating pulses is a temperature control cycle,
This temperature control cycle is assigned to each heating unit in a predetermined order,
In the temperature control cycle corresponding to the assigned heating unit, according to the temperature of the tip heated by the heating unit, the number of heating pulses supplied to the heating unit is sequentially determined and supplied. Temperature control method for soldering iron.

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