Patent Publication Number: US-2019168331-A1

Title: Torch for heat processing, power source apparatus, wire feed apparatus, and heat processing system

Description:
TECHNICAL FIELD 
     The present disclosure relates to a heat processing torch, a power source, a wire feeder, and a heat processing system. 
     BACKGROUND ART 
     A heat processing torch may be used for performing welding or cutting by the heat of the arc, and generally a usage rate for safe use is set with such a torch. The usage rate is a ratio (percentage) relating to a time of continuous use of the torch with respect to a predetermined period, and the upper limit is prescribed depending on the electric current to be used. A worker may, however, perform thermal processing beyond the upper limit of the usage rate. In that case, the temperature at the tip of the torch may increase due to the arc heat until the torch is damaged. 
     SUMMARY OF INVENTION 
     It is an object of the present disclosure to provide a heat processing torch and a heat processing system that can prevent thermal damage to the torch, in particular without affecting the quality of a workpiece. 
     According to a first aspect of the present disclosure, a heat processing torch is provided. The heat processing torch includes a sensor unit and a notification unit. The sensor unit detects a temperature at a predetermined position of the heat processing torch. The notification unit reports information, and gives notification of the temperature detected by the sensor unit. 
     According to a second aspect of the present disclosure, a heat processing system is provided. The heat processing system includes a heat processing torch provided by the first aspect of the present disclosure, and a power supply apparatus. The power supply apparatus supplies electric power to the heat processing torch. 
     According to a third aspect of the present disclosure, a power supply apparatus is provided. The power supply apparatus supplies electric power to a heat processing torch including a sensor for detecting a temperature at a predetermined position of the heat processing torch. The power supply apparatus includes a notification unit that gives notification of the temperature detected using the sensor. 
     According to a fourth aspect of the present disclosure, a heat processing system is provided. The heat processing system includes a power supply apparatus provided by the third aspect of the present disclosure, and the heat processing torch. 
     According to a fifth aspect of the present disclosure, a wire feed apparatus is provided. The wire feed apparatus feeds a wire electrode to a heat processing torch provided with a sensor for detecting a temperature at a predetermined position of the heat processing torch. The wire feed apparatus includes a notification unit that gives notification of the temperature detected using the sensor. 
     According to a sixth aspect of the present disclosure, a heat processing system is provided. The heat processing system includes a wire feed apparatus provided by the fifth aspect of the present disclosure, the heat processing torch, and a power supply apparatus that supplies electric power to the heat processing torch. 
     Other features and advantages of the present disclosure will become more apparent from the detailed description given below with reference to the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1A  is a schematic diagram showing the overall configuration of a welding system according to a first embodiment. 
         FIG. 1B  is a block diagram showing the functional configuration of a welding system according to the first embodiment. 
         FIG. 2A  is a front view of an example of a welding torch according to the first embodiment. 
         FIG. 2B  is a plan view of an example of a welding torch according to the first embodiment. 
         FIG. 3  is a flowchart for explaining torch temperature notification processing performed by a control unit. 
         FIG. 4  shows changes in a torch temperature when a worker performs welding work while recognizing the torch temperature displayed in a display. 
         FIG. 5A  is a partial front view of an example of a welding torch according to a second embodiment. 
         FIG. 5B  is a partial enlarged plan view of an example of a welding torch according to a second embodiment. 
         FIG. 6A  is a block diagram showing the functional configuration of a welding system according to a third embodiment. 
         FIG. 6B  is a block diagram showing the functional configuration of a welding system according to a fourth embodiment. 
     
    
    
     MODE FOR CARRYING OUT INVENTION 
     Embodiments of the present disclosure will be described below with reference to the drawings, in which a welding torch (welding system) is presented as an example. 
       FIGS. 1A and 1B  are diagrams for explaining a welding system A 1  according to a first embodiment.  FIG. 1A  is a schematic diagram showing the overall configuration of the welding system A 1  according to the first embodiment.  FIG. 1B  is a block diagram showing the functional configuration of the welding system A 1 . 
     As shown in  FIGS. 1A and 1B , the welding system A 1  includes a welding power supply apparatus  1 , a wire feed apparatus  2 , a welding torch  3 , power cables  41  and  42 , an electric power transmission line  5 , a signal line  8 , a gas cylinder  6  and a gas pipe  7 . In the present embodiment, the welding system A 1  corresponds to an example of a “heat processing system”, and the welding torch  3  corresponds to an example of a “heat processing torch”. One output terminal of the welding power supply apparatus  1  is connected to the welding torch  3  through the power cable  41 . The wire feed apparatus  2  feeds the wire electrode to the welding torch  3  and causes the tip of the wire electrode to protrude from the tip of the welding torch  3 . A contact chip disposed at the tip of the welding torch  3 , and via the chip the power cable  41  and the wire electrode are electrically connected. The other output terminal of the welding power supply apparatus  1  is connected to the workpiece W through the power cable  42 . The welding power supply apparatus  1  causes an arc to be generated between the tip of the wire electrode protruding from the tip of the welding torch  3  and the workpiece W, and supplies electric power to the arc. The welding system A 1  performs welding of the workpiece W with the heat of the arc. 
     The welding system A 1  uses shielding gas when performing welding. Shielding gas from the gas cylinder  6  is supplied to the tip of the welding torch  3  by the gas pipe  7 , which is provided so as to pass through the welding power supply apparatus  1  and the wire feed apparatus  2 . Electric power (for example, DC 24V) for driving e.g. a feed motor is supplied from the welding power supply apparatus  1  to the wire feed apparatus  2  through the electric power transmission line  5 . Also, the welding power supply apparatus  1  and the wire feed apparatus  2  communicate through the signal line  8 . The welding system A 1  may have a configuration in which cooling water circulates through the welding torch  3 . 
     The welding power supply apparatus  1  supplies electric power for arc welding to the welding torch  3 . The welding power supply apparatus  1  converts three-phase alternating current electric power input from an electric power system P into electric power suitable for arc welding, and outputs this electric power. Also, the welding power supply apparatus  1  converts the three-phase alternating current electric power input from the electric power system P into direct current electric power for driving e.g. the feed motor of the wire feed apparatus  2 , and outputs this electric power through the electric power transmission line  5  to the wire feed apparatus  2 . 
     The welding power supply apparatus  1  is controlled to output the electric power according to e.g. welding conditions, and the welding conditions are changed according to operation of an operation portion (not shown). Also, the welding power supply apparatus  1  changes the welding conditions according to a signal input from the welding torch  3  through the signal line  8 . 
     The wire feed apparatus  2  feeds the wire electrode to the welding torch  3 . The wire electrode passes through the interior of a liner provided inside a torch cable  39  and the welding torch  3 , and is guided to the tip of the welding torch  3 . The wire feed apparatus  2  drives e.g. the feed motor with the electric power supplied from the welding power supply apparatus  1  through the electric power transmission line  5 . This electric power is also supplied from the wire feed apparatus  2  to the welding torch  3  through an electric power transmission line (not shown) provided inside the torch cable  39 . The wire feed apparatus  2  communicates with the welding power supply apparatus  1  through the signal line  8 . Also, the wire feed apparatus  2  communicates with the welding torch  3  through a signal line (not shown) provided inside the torch cable  39 . Communications between the welding torch  3  and the welding power supply apparatus  1  are performed through the wire feed apparatus  2 . 
     The wire feed apparatus  2  and the welding torch  3  are connected by the torch cable  39 . The torch cable  39  is connected to abase end of the welding torch  3 , and disposed inside of the cable are the power cable  41 , the gas pipe  7 , the liner, the electric power transmission line and the signal line. 
     A connector  21  is a connection terminal for connecting the welding torch  3  and the wire feed apparatus  2 . For example, the connector  21  is a recessed connection terminal and connects the welding torch  3  and the wire feed apparatus  2  by inserting a protruding torch plug (not shown) provided at one end of the torch cable  39  of the welding torch  3 . The power cable  41 , the gas pipe  7 , the liner, the electric power transmission line  5  and the signal line  8  inside of the wire feed apparatus  2  are respectively configured to be connected to the power cable  41 , the gas pipe  7 , the liner, the electric power transmission line and the signal line inside of the torch cable  39  through this connector  21 . 
     The welding torch  3  performs welding of the workpiece W by welding electric power supplied from the welding power supply apparatus  1 . The welding torch  3  includes, as functional blocks, a communications unit  31 , a display unit  32 , an operation unit  33 , a storage unit  34 , a sensor unit  35 , and a control unit  36 . 
     The communications unit  31  performs communications with the wire feed apparatus  2 . The communications unit  31  transmits a signal input from the control unit  36  to the wire feed apparatus  2  through the signal line inside the torch cable  39 . Also, the communications unit  31  receives a signal input from the wire feed apparatus  2  through the signal line inside the torch cable  39 , and outputs the received signal to the control unit  36 . As a communications standard, for example, the CAN (Controller Area Network) standard is used. 
     The display unit  32  performs various display, and is provided with, for example, a display  321  (described later) that may be a liquid crystal display device. The display unit  32  is controlled by the control unit  36 , and performs display of e.g. welding conditions stored in the storage unit  34 , and detection values detected by the sensor unit  35 . The display unit  32  corresponds to an example of a “notification unit”. 
     The operation unit  33  has a plurality of operation means, and outputs operation of each operation means by a worker to the control unit  36  as an operation signal. As described later, a torch switch  331  and operation buttons  332  serve as the operation means. Note that other operation means may be provided in the operation unit  33 . 
     The storage unit  34  stores various setting values for welding conditions, and information regarding total welding time, for example. 
     The sensor unit  35  has a plurality of sensors, and outputs detection values of each sensor to the control unit  36 . In the present embodiment, the sensor unit  35  is provided with an acceleration sensor  351  and a temperature sensor  352  described later. Note that the sensor unit  35  may be provided with other sensors. 
     The control unit  36  controls the welding torch  3 , and is realized by, for example, a microcomputer. The control unit  36  performs predetermined processing according to an operation signal input from the operation unit  33 . Also, the control unit  36  outputs the detection values input from the sensor unit  35  to be displayed, performs a predetermined calculation based on the detection values, and uses the calculation results for processing. Also, the control unit  36  controls communications by the communications unit  31 , writing and reading of information of the storage unit  34 , and display by the display unit  32 . The specific content of control will be described later. 
       FIGS. 2A and 2B  show the external appearance of an example of the welding torch  3 .  FIG. 2A  is a front view, and  FIG. 2B  is a plan view. As shown in  FIGS. 2A and 2B , the welding torch  3  includes a torch body  37 , a handle  38 , a control substrate  381 , the torch switch  331 , the operation buttons  332 , the display  321 , the acceleration sensor  351 , the temperature sensor  352 , and the torch cable  39 . 
     The torch body  37  is a tubular member made of metal, inside of which are disposed the liner through which the welding cable is inserted, the power cable  41 , and the gas pipe  7 . A nozzle  371  is attached to the tip of the torch body  37 . The torch body  37  has a curved portion such that the worker can easily direct the nozzle  371  at the workpiece W. 
     The handle  38  is a part to be gripped by the worker and is provided so as to hold a base end portion of the torch body  37 . The worker grips this handle  38  and performs welding work. The torch switch  331 , the operation buttons  332 , and the display  321  are disposed in the handle  38 . Also, the control substrate  381  is disposed inside the handle  38 . Circuits constituting the communications unit  31 , the display unit  32 , the operation unit  33 , the storage unit  34 , the sensor unit  35 , and the control unit  36  are mounted on the control substrate  381 . 
     The torch switch  331  is an operation means for receiving welding start/stop operation, and is disposed at a location where a worker gripping the handle  38  can easily perform a pressing operation with their index finger. By an on operation (pressing) of the torch switch  331 , an operation signal is output to the control unit  36 , and when that operation signal is input to the welding power supply apparatus  1 , the welding power supply apparatus  1  outputs welding electric power. When the on operation is released, the welding power supply apparatus  1  stops the output of welding electric power. That is, welding is performed only while the torch switch  331  is being pressed. 
     The display  321  performs various display, and is disposed on the opposite side of the handle  38  as the torch switch  331 , such that a worker who performs welding work by gripping the handle  38  can easily view a screen. The display  321  corresponds to an example of a “display apparatus”. 
     The operation buttons  332  are operation means for switching screens or changing various settings values, and are disposed between the grip portion of the handle  38  and the display  321  on the same side of the handle  38  as the display  321 . The operation buttons  332  include an up button  332   a , a down button  332   b , a left button  332   c , and a right button  332   d . When each of the buttons  332   a  to  332   d  is pressed, a corresponding operation signal is output to the control unit  36 , and the control unit  36  performs corresponding processing. The left button  332   c  and the right button  332   d  are operation means for switching the screen to be displayed in the display  321 . The up button  332   a  and the down button  332   b  are operation means for changing the settings values being displayed in the display  321 . 
     A sensor that detects pressing of each operation button  332  is disposed on the control substrate  381 . Further, the display  321  is disposed on the same control substrate  381 . In the present embodiment, the display screen of the display  321  has a predetermined angle with respect to the control substrate  381  such that the worker can easily operate each operation button  332  while viewing the display screen of the display  321 . Note that the display  321  may be disposed such that the display screen is parallel to the substrate. On the control substrate  381  there are mounted a microcomputer serving as the control unit  36 , a memory serving as the storage unit  34 , a communications module serving as the communications unit  31 , and also various electronic components. The acceleration sensor  351  is also mounted on the control substrate  381 . 
     The acceleration sensor  351  is a three-axis acceleration sensor, and detects acceleration in each axis direction and outputs detection values to the control unit  36 . The control unit  36  calculates inclination information of the welding torch  3  based on the detection values input from the acceleration sensor  351  of the sensor unit  35 . Note that the sensor unit  35  may be provided with a gyro sensor instead of the acceleration sensor  351 . 
     The temperature sensor  352  detects temperature, and includes a thermistor  352   a  and a temperature measurement portion (not shown). In the present embodiment, the thermistor  352   a  is disposed most to the tip end side among the portions covered by the handle  38  of the torch body  37 . The torch body  37  is more likely to be damaged by heat from an arc at a location further toward the tip end side. Accordingly, it is desirable to detect the temperature further toward the tip end side. In the present embodiment, the thermistor  352   a  is disposed at a position that is further toward the tip end side of the torch body  37 , and where the thermistor  352   a  is not exposed. Note that the position where the thermistor  352   a  is disposed is not limited, and the thermistor  352   a  may be disposed at a position further toward the tip end side of the torch body  37  that is not covered by the handle  38 . Also, if the thermistor  352   a  can withstand heat due to an arc, the thermistor  352   a  may be disposed within the nozzle  371 . Conversely, if the thermistor  352   a  is not able to withstand a high temperature, the thermistor  352   a  may be disposed away from the tip portion where an arc is generated, in the base end portion of the torch body  37  where the temperature is comparatively low. Wherever the thermistor  352   a  is disposed, it is sufficient to acquire and set in advance the temperature at the position where the thermistor  352   a  is disposed in a state where it is possible for the welding torch  3  to be damaged. However, the manner of heat transfer is not necessarily constant, so the temperature at which the welding torch  3  will be damaged can be judged more reliably by detecting the temperature at the position where damage actually occurs. The thermistor  352   a  corresponds to an example of a “sensor”. The thermistor  352   a  is connected to the temperature measurement portion, which is mounted on the control substrate  381  through two lead wires not shown. In the temperature measurement portion, an electric current is passed through the thermistor  352   a , the potential difference between the two lead wires is measured, the resistance value of the thermistor  352   a  is calculated, and a temperature corresponding to the calculated resistance value is calculated. Thus, the temperature measurement portion measures a temperature T (hereinafter referred to as the “torch temperature”) in a portion where the thermistor  352   a  of the torch body  37  makes contact. The temperature measurement portion outputs the detected torch temperature T to the control unit  36 . Note that the temperature sensor  352  is not limited to a sensor using the thermistor  352   a , and another sensor such as a thermocouple may be used. 
     Note that the external appearance of the welding torch  3  is not limited by the external appearance described above. For example, the placement and shape of the torch switch  331 , the operation buttons  332 , and the display  321  are not limited. Also, in the present embodiment, a case is disclosed where the operation buttons  332  are four independent buttons, but a single cross-shaped button may be used. Also, the number of buttons is not limited. 
     Next is a description of a function to give notification of the torch temperature T of the welding torch  3 . 
     The control unit  36  inputs the torch temperature T from the sensor unit  35 . Then, when the torch temperature T reaches a predetermined temperature Tb, the control unit  36  outputs a warning sound from a speaker not shown to prompt attention from the worker. Also, in a case where the torch temperature T has become a predetermined temperature Td or more, the control unit  36  stops the supply of electric power from the welding power supply apparatus  1  to prevent damage of the welding torch  3 . Specifically, the control unit  36  causes the communications unit  31  to output a stop signal. After receiving the stop signal, the welding power supply apparatus  1  stops supplying electric power. 
     Also, the control unit  36  outputs the torch temperature T to the display unit  32  and causes the torch temperature T to be displayed in the display  321 . The torch temperature T may always be displayed in the display  321 , or may be displayed when the worker switches screens by operating the operation buttons  332  to select a screen that displays the torch temperature T (a torch temperature display screen). 
       FIG. 3  is a flowchart for explaining torch temperature T notification processing performed by the control unit  36 . This processing is started when the welding torch  3  starts. 
     First, the torch temperature T is detected (S 1 ). Specifically, the torch temperature T detected by the temperature sensor  352  is input to the control unit  36 . Next, the torch temperature T is displayed in the display  321  (S 2 ). Specifically, the control unit  36  outputs the torch temperature T to the display unit  32 , and the display unit  32  displays the torch temperature T in the display  321 . Note that if the torch temperature T is not set to always be displayed in the display  321 , the torch temperature T is displayed when the screen of the display  321  is switched to the torch temperature display screen. 
     Next, it is determined whether or not the torch temperature T is the temperature Td or more (S 3 ). The temperature Td is set in advance as the temperature at which the welding torch  3  can be damaged by heat. If the torch temperature T is the temperature Td or more (S 3 : YES), electric power supply is stopped to prevent damage of the welding torch  3  (S 4 ), and the process returns to step S 1 . Specifically, the control unit  36  causes the communications unit  31  to output a stop signal. After receiving the stop signal, the welding power supply apparatus  1  stops supplying electric power. 
     In step S 3 , if the torch temperature T is less than the temperature Td (S 3 : NO), it is determined whether or not the torch temperature T is the temperature Tb (S 5 ). The temperature Tb is set in advance as a temperature judged to require attention because it is approaching the temperature Td. If the torch temperature T is the temperature Tb (S 5 : YES), a warning is issued to the worker (S 6 ). Specifically, the control unit  36  issues an instruction to output a warning sound to a sound output unit not shown. The sound output unit, upon input of the instruction, outputs a warning sound (for example, a buzzer sound) via a speaker. Instead of a simple warning sound, it is also possible to output voice guidance (like “the torch temperature is high”) so as to prompt the user to pay attention to the torch temperature T. Also, a guidance message prompting the user to pay attention to the torch temperature T may be displayed on the display  321 . 
     In step S 5 , if the torch temperature T is not the temperature Tb (S 5 : NO), the process returns to step S 1 . That is, if the torch temperature T is less than the temperature Td and is not the temperature Tb, the torch temperature T is merely displayed. 
     Note that the processing shown in the flowchart in  FIG. 3  is only one example, and the torch temperature T notification processing performed by the control unit  36  is not limited to the processing described above. 
     The worker can recognize the torch temperature T by viewing the display of the display  321 . The worker is informed in advance with information that when the torch temperature T is the temperature Tb or more it is necessary to pay attention, and that when the torch temperature T is the temperature Td or more damage due to heat is possible. Also, in the present embodiment, a warning sound is output when the torch temperature T reaches the temperature Tb, and the supply of electric power is stopped when the torch temperature T is the temperature Td or more. The worker can continue to perform work by viewing the torch temperature T displayed in the display  321  and not allowing the torch temperature T to become the temperature Td or more. Note that if the temperature Tb is set too low, there may be cases where the worker is prompted to pay attention too soon, and so attention of the worker is not sustained. Conversely, if the temperature Tb is set too high, there may be cases where the time until the torch temperature T reaches the temperature Td is too short, and so the worker cannot make appropriate adjustments. Accordingly, based on these facts, it is necessary to set the temperature Tb to an appropriate temperature. 
       FIG. 4  shows changes in the torch temperature T when the worker performs welding work while recognizing the torch temperature displayed in the display  321 . 
     Welding is started at a time t 1  in a state with the torch temperature T at a temperature Ta. The torch temperature T rises with the passage of time. The worker recognizes that the torch temperature T displayed in the display  321  is approaching the temperature Tb, and from a time t 2  the worker lowers the usage rate and performs welding work such that the torch temperature T does not reach the temperature Td. From a time t 4 , the torch temperature T decreases from a peak at a temperature Tc, and the worker can recognize that it is not a problem to raise the usage rate a little more. The worker, while viewing the torch temperature T displayed on the display  321 , can continue the welding work by raising and lowering the usage rate such that the torch temperature T does not reach the temperature Td. 
     Note that, hypothetically, if the worker fails to recognize the torch temperature T, the worker continues the welding work without knowing how high the torch temperature T has risen, and as indicated by the broken line in  FIG. 4 , at the time t 3  the torch temperature T reaches the temperature Td (broken line in  FIG. 4 ). In this case, if the electric power supply is stopped at the temperature Td, the welding work is stopped suddenly, which may affect the quality of the workpiece W. On the other hand, if the electric power supply is not stopped, the welding torch  3  may be damaged by heat. 
     According to the present embodiment, the torch temperature T detected by the temperature sensor  352  is displayed in the display  321 . Therefore, the worker can recognize the torch temperature T by viewing the display of the display  321 . As a result, the worker can continue work by adjusting the usage rate such that the torch temperature T does not reach or exceed the temperature (the temperature Td) at which damage by heat is possible. Accordingly, it is possible to prevent the welding torch  3  from being damaged by heat, and it is possible to prevent the quality of the workpiece W from being affected due to suddenly stopping the welding work. 
     Also, according to the present embodiment, a warning sound is output when the torch temperature T reaches a temperature (the temperature Tb) requiring caution, so it is possible to prompt the worker to pay attention. Also, when the torch temperature T is the temperature Td or more, the supply of electric power is stopped. Therefore, even if the worker fails to adjust the usage rate, the torch temperature T does not rise beyond the temperature Td, so damage to the welding torch  3  due to heat can be prevented. 
     Also, according to the present embodiment, the torch temperature T is displayed in the display  321  provided in the welding torch  3 , so it is possible to know the torch temperature T by a means close at hand while performing the welding work. 
     Note that, in the present embodiment, a case is described where the torch temperature T detected by the temperature sensor  352  is displayed as-is, but this is not a limitation. For example, the control unit  36  may estimate the tip temperature of the torch body  37  from the torch temperature T and display the estimated tip temperature. In this case, the temperature sensor  352  and the control unit  36  correspond to an example of a “sensor unit”. 
     Also, in the present embodiment, a case is described where the torch temperature T is displayed in the display  321 , but this is not a limitation. Other notification methods may be used as long as the worker can recognize the torch temperature T. For example, the worker may be notified of the torch temperature T by sound from a speaker not shown. Also, a configuration may be adopted in which an LED lamp capable of changing its light emission color is provided, and the worker is notified of the torch temperature T by changing the light emission color according to the torch temperature T. In these cases, the speaker or the LED lamp corresponds to an example of a “notification unit”. 
     Also, in the present embodiment, a case is described where the welding power supply apparatus  1  and the wire feed apparatus  2  communicate through the signal line  8 , but this is not a limitation. For example, communications may be performed by superimposing signals on the power cables  41  and  42  or the electric power transmission line  5 . In this case, the signal line  8  connecting the welding power supply apparatus  1  and the wire feed apparatus  2  is not required. 
       FIGS. 5A and 5B , and  FIGS. 6A and 6B , show other embodiments of the present disclosure. Note that in these drawings, the same reference signs as those in the above first embodiment denote the same or similar elements as those in the above first embodiment. 
       FIGS. 5A and 5B  are views for explaining a welding system A 2  according to a second embodiment, and show part of an external view of an example of a welding torch  3 ′ according to the second embodiment.  FIG. 5A  is a partial enlarged front view, and  FIG. 5B  is a partial enlarged plan view. 
     The welding system A 2  shown in  FIGS. 5A and 5B  differs from the welding system A 1  according to the first embodiment in that the thermistor  352   a  of the temperature sensor  352  is disposed on the control substrate  381 , and the temperature sensor  352  measures a temperature T′ of the control substrate  381  (hereinafter referred to as a “substrate temperature”). 
     Because the temperature of the torch body  37  increases due to the heat of the arc, the temperature of the control substrate  381  disposed inside the handle  38  also rises. Some components mounted on the control substrate  381  are vulnerable to heat. For example, if the microcomputer malfunctions due to heat, the temperature sensor  352  cannot detect the temperature. Also, if the display  321  fails due to heat, it is impossible to display the detected temperature. In particular, the display  321  is vulnerable to heat, and the allowable temperature is, for example, about 70° C. In the present embodiment, the temperature sensor  352  measures the temperature (the substrate temperature T′) of the control substrate  381 , and displays the substrate temperature T′ in the display  321 . 
     As shown in  FIGS. 5A and 5B , in the welding torch  3 ′, the thermistor  352   a  is disposed near the display  321  on the control substrate  381 . The temperature sensor  352  detects the temperature near the display  321  of the control substrate  381  as the substrate temperature T′. 
     The control unit  36  inputs the substrate temperature T′ from the sensor unit  35  (the temperature sensor  352 ). Then, when the substrate temperature T′ reaches a predetermined temperature Tb′ (for example, 60° C.), the control unit  36  outputs a warning sound from a speaker not shown to prompt attention from the worker. Also, in a case where the substrate temperature T′ is a predetermined temperature Td′ (for example, 70° C.) or more, the control unit  36  stops the supply of electric power from the welding power supply apparatus  1  to prevent damage to the welding torch  3  (the components mounted on the control substrate  381 ). Also, the control unit  36  outputs the substrate temperature T′ to the display unit  32 , and displays the substrate temperature T′ in the display  321 . 
     According to the second embodiment, the substrate temperature T′ detected by the temperature sensor  352  is displayed in the display  321 . Therefore, the worker can recognize the substrate temperature T′ by viewing the display of the display  321 . As a result, the worker can continue work by adjusting the usage rate such that the substrate temperature T′ does not reach or exceed the temperature (the temperature Td′) at which damage by heat is possible. Accordingly, it is possible to prevent the welding torch  3  from being damaged by heat, and it is possible to prevent the quality of the workpiece W from being affected due to suddenly stopping the welding work. That is, similar effects as in the first embodiment can also be exhibited in the second embodiment. 
     Note that a configuration may also be adopted in which a thermistor  352   a  is disposed in each of the torch body  37  and the control substrate  381 , and the temperature sensor  352  detects both the torch temperature T and the substrate temperature T′. In this case, both the torch temperature T and the substrate temperature T′ may be displayed, or a configuration may be adopted in which it is possible to perform display by switching between the torch temperature display screen and the substrate temperature display screen. 
     Also, the control unit  36  may estimate the tip temperature of the torch body  37  from the substrate temperature T′ detected by the temperature sensor  352 , and display the estimated tip temperature. In this case, the temperature sensor  352  and the control unit  36  correspond to an example of a “sensor unit”. 
       FIG. 6A  is a block diagram showing the functional configuration of a welding system A 3  according to a third embodiment. 
     The welding system A 3  shown in  FIG. 6A  differs from the welding system A 1  according to the first embodiment in that the torch temperature T detected by the temperature sensor  352  is displayed in a display unit  24  of the wire feed apparatus  2 . 
     As shown in  FIG. 6A , the wire feed apparatus  2  includes a first communications unit  22 , a second communications unit  23 , the display unit  24 , and a control unit  25 . The first communications unit  22  communicates with the welding torch  3  through a signal line (not shown) provided inside the torch cable  39 . The second communications unit  23  communicates with the welding power supply apparatus  1  through the signal line  8 . The display unit  24  performs various display, and is provided with, for example, a display (not shown) that may be a liquid crystal display device. The display unit  24  corresponds to an example of a “notification unit”. The control unit  36  controls the wire feed apparatus  2 . 
     The control unit  36  of the welding torch  3  causes the torch temperature T input from the sensor unit  35  to be transmitted to the communications unit  31 . The first communications unit  22  of the wire feed apparatus  2  receives the torch temperature T transmitted from the communications unit  31  and outputs the torch temperature T to the control unit  25 . The control unit  25  outputs the torch temperature T to the display unit  24 , and displays the torch temperature T in the display. 
     According to the third embodiment, the torch temperature T detected by the temperature sensor  352  is displayed in the display of the wire feed apparatus  2 . The worker can recognize the torch temperature T by viewing the display shown by the display of the wire feed apparatus  2 . Therefore, the worker can continue work by adjusting the usage rate such that the torch temperature T does not reach or exceed the temperature (the temperature Td) at which damage by heat is possible. Accordingly, it is possible to prevent the welding torch  3  from being damaged by heat, and it is possible to prevent the quality of the workpiece W from being affected due to suddenly stopping the welding work. Also, in the case of the third embodiment, the welding torch  3  does not need to include the display  321  (the display unit  32 ). Also, in a case where the temperature measurement portion of the temperature sensor  352  is disposed in the wire feed apparatus  2 , and the temperature measurement portion and the thermistor  352   a  are connected by two unshown lead wires provided inside the torch cable  39 , the welding torch  3  does not need to include the operation unit  33 , the communications unit  31 , the storage unit  34 , and the control unit  36 . That is, if the thermistor  352   a  (or another sensor for detecting the temperature) is provided in the welding torch  3 , the torch temperature T can be detected by the wire feed apparatus  2  and displayed. 
       FIG. 6B  is a block diagram showing the functional configuration of a welding system A 4  according to a fourth embodiment. 
     The welding system A 4  shown in  FIG. 6B  differs from the welding system A 1  according to the first embodiment in that the torch temperature T detected by the temperature sensor  352  is displayed in a display unit  12  of the welding power supply apparatus  1 . 
     As shown in  FIG. 6B , the welding power supply apparatus  1  includes a communications unit  11 , the display unit  12 , and a control unit  13 . The communications unit  11  communicates with the wire feed apparatus  2  through the signal line  8 . The wire feed apparatus  2  communicates with the welding torch  3 , so the welding power supply apparatus  1  can communicate with the welding torch  3  through the wire feed apparatus  2 . The display unit  12  performs various display, and is provided with, for example, a display (not shown) that is a liquid crystal display device. The display unit  12  corresponds to an example of a “notification unit”. The control unit  13  controls the welding power supply apparatus  1 . 
     The control unit  36  of the welding torch  3  causes the torch temperature T input from the sensor unit  35  to be transmitted to the communications unit  31 . The communications unit  11  of the welding power supply apparatus  1  receives the torch temperature T transmitted from the communications unit  31  and outputs the torch temperature T to the control unit  13 . The control unit  13  outputs the torch temperature T to the display unit  12 , and displays the torch temperature T in the display. 
     According to the fourth embodiment, the torch temperature T detected by the temperature sensor  352  is displayed in the display of the welding power supply apparatus  1 . The worker can recognize the torch temperature T by viewing the display shown by the display of the wire welding power supply apparatus  1 . Therefore, the worker can continue work by adjusting the usage rate such that the torch temperature T does not reach or exceed the temperature (the temperature Td) at which damage by heat is possible. Accordingly, it is possible to prevent the welding torch  3  from being damaged by heat, and it is possible to prevent the quality of the workpiece W from being affected due to suddenly stopping the welding work. Also, in the case of the fourth embodiment, the welding torch  3  does not need to include the display  321  (the display unit  32 ). Also, in a case where the temperature measurement portion of the temperature sensor  352  is disposed in the wire feed apparatus  2 , and the temperature measurement portion and the thermistor  352   a  are connected by two unshown lead wires provided inside the torch cable  39 , the welding torch  3  does not need to include the operation unit  33 , the communications unit  31 , the storage unit  34 , and the control unit  36 . That is, if the thermistor  352   a  (or another sensor for detecting the temperature) is provided in the welding torch  3 , the torch temperature T can be detected by the wire feed apparatus  2  and displayed by the welding power supply apparatus  1 . 
     In the above first to fourth embodiments, a case related to a welding torch (a welding system) is described, but this is not a limitation. For example, the teachings of the present disclosure are also applicable to an arc cutting torch (arc cutting system) that cuts a workpiece W using an arc generated at a tip, or an arc gouging torch (arc gouging system) that performs groove engraving on a workpiece W. Furthermore, the teachings of the present disclosure is not limited to thermal processing by an arc, and is also applicable to a heat processing torch (heat processing system) that performs thermal processing such as gas welding or resistance welding. The teachings of the present disclosure are effective for preventing damage to a heat processing torch. 
     The heat processing torch, the power supply apparatus, the wire feed apparatus, and the heat processing system according to the present disclosure are not limited to the embodiments described above. Various design modifications can be freely made to the specific configuration of each part of the heat processing torch, the power supply apparatus, the wire feed apparatus, and the heat processing system according to the present disclosure. 
     The above disclosure encompasses embodiments according to the following clauses. 
     (Clause 1) 
     A heat processing torch, comprising: 
     a sensor unit that detects a temperature at a predetermined position of the heat processing torch; and 
     a notification unit that reports information and gives notification of the temperature detected by the sensor unit. 
     (Clause 2) 
     The heat processing torch according to clause 1, 
     wherein the notification unit includes a display device to display the temperature detected by the sensor unit. 
     (Clause 3) 
     The heat processing torch according to clause 1 or 2, 
     wherein the notification unit includes a speaker to give audio notification of the temperature detected by the sensor unit. 
     (Clause 4) 
     The heat processing torch according to any one of clauses 1 to 3, further comprising a torch body, 
     wherein the predetermined position is at a base end portion of the torch body. 
     (Clause 5) 
     The heat processing torch according to any one of clauses 1 to 3, further comprising a control substrate where a circuit that performs control is mountable, 
     wherein the predetermined position is at the control substrate. 
     (Clause 6) 
     The heat processing torch according to any one of clauses 1 to 5, 
     wherein the sensor unit includes a thermistor. 
     (Clause 7) 
     The heat processing torch according to any one of clauses 1 to 6, 
     wherein welding is performed using heat from an arc. 
     (Clause 8) 
     A heat processing system, comprising: 
     a heat processing torch according to any one of clauses 1 to 7; and 
     a power supply apparatus that supplies electric power to the heat processing torch. 
     (Clause 9) 
     A power supply apparatus that supplies electric power to a heat processing torch provided with a sensor for detecting a temperature at a predetermined position of the heat processing torch, the power supply apparatus comprising: 
     a notification unit that gives notification of the temperature detected using the sensor. 
     (Clause 10) 
     A heat processing system, comprising: 
     a power supply apparatus according to clause 9; and the heat processing torch. 
     (Clause 11) 
     A wire feed apparatus that feeds a wire electrode to a heat processing torch provided with a sensor for detecting a temperature at a predetermined position of the heat processing torch, the wire feed apparatus comprising: 
     a notification unit that gives notification of the temperature detected using the sensor. 
     (Clause 12) 
     A heat processing system, comprising: 
     a wire feed apparatus according to clause 11; 
     the heat processing torch; and 
     a power supply apparatus that supplies electric power to the heat processing torch.