JP2019209337A - Heating furnace, and workpiece temperature acquiring method in the heating furnace - Google Patents

Abstract

To provide a heating furnace and a workpiece temperature acquiring method in the heating furnace by which a temperature of a workpiece heated in the furnace can be acquired precisely.SOLUTION: A heating furnace includes a deformation part 80 which is arranged on a heat exchanger W and changes its shape when heated at a predetermined temperature or higher, and a camera 71 which detects the shape of the deformation part 80. A controller acquires a temperature of the heat exchanger W on the basis of the shape of the deformation part 80 detected by the camera 71. Thereby, the temperature of the heat exchanger W can be acquired by monitoring a change of the shape of the deformation part 80, and bonding failure of metal components of the heat exchanger W caused by insufficient heating in a furnace can be suppressed.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a heating furnace used when, for example, a plurality of metal parts made of aluminum or the like are joined to each other by brazing, and a work temperature acquisition method in the heating furnace.

  Conventionally, this type of heating furnace includes a heater for heating the inside of the furnace and a temperature sensor for detecting the temperature in the furnace, and controls the output of the heater based on the temperature detected by the temperature sensor. Thus, there is known one in which the temperature in the furnace is set to the set temperature (see, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 04-31462

  In the heating furnace, when the workpiece located in the furnace is heated by the heater, whether or not the temperature of the workpiece located in the furnace is heated to a target temperature even if the temperature in the furnace is heated to the set temperature. Cannot be determined. For this reason, in the said heating furnace, the temperature of a workpiece | work may not be heated to the target temperature. If the workpiece is not heated to the target temperature, poor bonding may occur when the metal parts are connected to each other by brazing.

  An object of the present invention is to provide a heating furnace capable of accurately acquiring the temperature of a workpiece heated in the furnace and a method for acquiring a workpiece temperature in the heating furnace.

  In order to achieve the above object, the heating furnace of the present invention is a heating furnace provided with a heater that heats a workpiece located in the furnace, and is provided in the vicinity of the workpiece in the furnace or on the workpiece, and the heating furnace has a predetermined temperature or higher. A deformed portion whose shape changes when heated, a shape detecting means for detecting the shape of the deformed portion, a workpiece temperature acquiring means for acquiring the temperature of the workpiece based on the shape of the deformed portion detected by the shape detecting means, It has.

  Further, the work temperature acquisition method in the heating furnace of the present invention is a work temperature acquisition method in the heating furnace that acquires the temperature of the work heated by the heater in order to achieve the above-mentioned object, and is above a predetermined temperature. A deformed portion whose shape changes when heated is provided near or in the work in the furnace, the shape of the deformed portion is detected, and the temperature of the work is acquired based on the detected shape of the deformed portion.

  Thereby, the temperature of a workpiece | work is acquired by monitoring the change of the shape of a deformation | transformation part.

  According to the present invention, since the temperature of the workpiece can be acquired by monitoring the change in the shape of the deformed portion, the bonding failure between the metal parts of the workpiece due to insufficient output or excessive output of the heater in the furnace. It becomes possible to suppress.

It is a schematic block diagram of the brazing apparatus which shows one Embodiment of this invention. It is a principal part schematic block diagram of a brazing apparatus. It is a block diagram which shows a control system. It is a figure of the heat exchanger provided with a deformation | transformation part.

  1 to 4 show an embodiment of the present invention.

  A brazing apparatus 1 to which a heating furnace and a workpiece temperature acquisition method in the heating furnace of the present invention are applied is for brazing a heat exchanger W as a workpiece used as an evaporator of a vehicle air conditioner. is there. The heat exchanger W is formed by brazing and joining together a plurality of aluminum alloy parts.

  As shown in FIG. 1, the brazing device 1 includes a transport device 10 for transporting the heat exchanger W, a drying furnace 20 in order from the upstream side to the downstream side in the transport direction of the transport device 10, The front chamber 30, the heating furnace 40, the cooling chamber 50, and the rear chamber 60 are provided.

  The transport device 10 includes, for example, a driving roller 11 driven by an electric motor, a driven roller 12 that is rotatably provided, and a mesh belt 13 that is wound around the driving roller 11 and the driven roller 12. The conveying device 10 drives the driving roller 11 to send the mesh belt 13 wound around the driving roller 11 and the driven roller 12 in the conveying direction, thereby causing the heat exchanger W placed on the mesh belt 13 to move. Move in the transport direction.

  The drying furnace 20 has an electric heater 21 in the furnace, and heats the heat exchanger W located in the furnace by the electric heater 21 to evaporate the processing oil applied to the heat exchanger W.

  The front chamber 30 is supplied with nitrogen gas, and the indoor heat exchanger W is located in the nitrogen gas atmosphere.

  The heating furnace 40 is supplied with nitrogen gas in the furnace. Moreover, the heating furnace 40 has a plurality of electric heaters 41 in the furnace, and heats the heat exchanger W located in the furnace by the electric heaters 41 to perform brazing. The heating furnace 40 is divided into a plurality of zones 1, 2,..., N (hereinafter referred to as 1 to n) in the transport direction of the heat exchanger W, and from the upstream side to the downstream side in the transport direction. For example, the electric heaters 41-1, 41-2,..., 41-n (hereinafter referred to as 41-n in each of the zones 1 to n) so that the temperature in the furnace gradually increases within a range of + 400 ° C. to + 600 ° C. 1 to n) is adjusted. Moreover, as shown in FIG. 2, the connection part 40a which connects the zone of the heating furnace 40 is formed in the exit side of each zone 1-n of the heating furnace 40. As shown in FIG. On the upper surface of the connecting portion 40a, a window 40b is provided for detecting the shape of a deformed portion, which will be described later, provided in the heat exchanger W transferred by the transfer device 10 in the furnace from the outside of the furnace.

  The cooling chamber 50 is supplied with nitrogen gas in the furnace, and cools the heat exchanger W brazed in a nitrogen gas atmosphere filled in the chamber.

  The heat exchanger W that has been cooled in the cooling chamber 50 and brazed is transported to the rear chamber 60.

  Moreover, the brazing apparatus 1 is provided with the controller 70 for controlling the output of the electric heater 41, as shown in FIG.

  The controller 70 has a CPU, ROM, and RAM. When the controller 70 receives an input signal from a device connected to the input side, the CPU reads a program stored in the ROM based on the input signal, and stores a state detected by the input signal in the RAM. The output signal is transmitted to a device connected to the output side.

  On the input side of the controller 70, a plurality of cameras 71 as shape detection means for photographing a deformation part (described later) of the heat exchanger W conveyed by the conveying device 10 in the heating furnace 40 from the outside of the furnace through the window 40 b. -1, 71-2, ..., 71-n (hereinafter referred to as 71-1 to n) are connected. A plurality of electric heaters 41-1 to 41-n are connected to the output side of the controller 70.

  As the plurality of cameras 71-1 to 71-n, laser cameras capable of photographing even in a dark place are used by using laser light. As shown in FIG. 2, the plurality of cameras 71-1 to 7-n are attached to the outside of the furnace of the window 40b and photograph a deformed portion, which will be described later, of the heat exchanger W conveyed by the conveying device 10 from above.

  The heat exchanger W includes a pair of heat exchange units 100 arranged in the flow direction of the air that exchanges heat with the refrigerant. As shown in FIG. 4, the heat exchange unit 100 includes a pair of headers 101 that are spaced apart from each other, a plurality of flat tubes 102 that connect between the pair of headers 101, and adjacent flat tubes 102. And fins 103 provided on the surface.

  One header 101 of one heat exchange unit 100 is connected to a refrigerant inflow pipe 101a for allowing a refrigerant to exchange heat with air in the heat exchanger W. In addition, a refrigerant outflow pipe 101 b for allowing the refrigerant that has exchanged heat with air in the heat exchanger W to flow out is connected to one header 101 of the other heat exchange unit 100.

  The refrigerant inflow pipe 101a is provided with a deforming portion 80 whose shape changes when heated.

  Each of the deformable portions 80 extends in the circumferential direction of the refrigerant inflow tube 101a and is spaced from each other in the axial direction, and protrudes from the outer peripheral surface of the refrigerant inflow tube 101a. ..., 80-n (hereinafter referred to as 80-1 to n).

  Each of the plurality of protruding pieces 80-1 to 80-n is made of a brazing material that melts when heated. The plurality of projecting pieces 80-1 to 80-n have different melting temperatures by different silicon contents. The plurality of protruding pieces 80-1 to 80-n are melted and changed in shape when heated to a set temperature.

  In the brazing device 1 configured as described above, the heat exchanger W transported by the transport device 10 sequentially passes through the drying furnace 20, the front chamber 30, the heating furnace 40, the cooling chamber 50, and the rear chamber 60. Then, brazing is performed, and a plurality of components are joined together to form a single body.

  When the heat exchanger W is brazed by the brazing apparatus 1, the controller 70 calculates the temperature of the heat exchanger W in each of the zones 1 to n based on the images photographed by the plurality of cameras 71-1 to 7-n. It acquires as an acquisition means and adjusts the output of the electric heaters 41-1 to 41-n based on the acquired temperature of the heat exchanger W.

  More specifically, the controller 70 photographs the deformed portions 80 after passing through the zones 1 to n with the cameras 71-1 to n, and the projecting pieces 80-1 to 80-n of the deformed portion 80 are melted. It is determined whether or not, and the outputs of the electric heaters 41-1 to 41-n are adjusted based on the determination result.

  For example, in the connecting portion 40a on the exit side of the zone 1, the deforming portion 80 is such that the protruding piece 80-1 corresponding to the zone 1 is melted and the protruding pieces 80-2 to n corresponding to the zones 2 to n are melted. If it is detected that the shape is maintained, it is determined that the heat exchanger W in the zone 1 has been heated to the target temperature.

  In addition, when it is detected that all the projecting pieces 80-1 to 80-n including the projecting pieces 80-1 corresponding to the zone 1 are not melted, the heat exchanger W in the zone 1 reaches the target temperature. Determine that it is not heated.

  Further, when it is detected that the protruding piece 80-1 corresponding to the zone 1 is melted and the protruding pieces 80-2 to n corresponding to the zones 2 to n are melted, the heat exchanger W in the zone 1 is the target. It is determined that it is heated to a temperature or higher.

  As described above, by determining whether or not each of the plurality of protruding pieces 80-1 to 80-n is melted, the heating temperature of the heat exchanger W in each zone is acquired, and the heat exchanger W in each zone is acquired. Adjust the outputs of the electric heaters 41-1 to 41-n so as to reach the target heating temperature.

  As described above, according to the heating furnace of the present embodiment, the deformable portion 80 that is provided in the heat exchanger W and changes its shape when heated to a predetermined temperature or more, and the camera 71 that detects the shape of the deformable portion 80, , And the controller 70 acquires the temperature of the heat exchanger W based on the shape of the deformable portion 80 detected by the camera 71.

  Further, according to the workpiece temperature acquisition method of the present embodiment, the deformation unit 80 whose shape changes when heated to a predetermined temperature or more is provided in the heat exchanger W, the shape of the deformation unit 80 is detected, and the detected deformation unit is detected. The temperature of the heat exchanger W is acquired based on the 80 shape.

  Thereby, since the temperature of the heat exchanger W can be acquired by monitoring the change in the shape of the deformed portion 80, the metal parts of the heat exchanger W due to insufficient output of the electric heater 41 in the furnace can be obtained. It becomes possible to suppress poor bonding.

  The deformable portion 80 is a member that melts when heated to a predetermined temperature or higher.

  Thereby, since the deformation | transformation part 80 fuse | melts by heating, since the deformation | transformation part 80 does not remain in the heat exchanger W after brazing, it does not affect the appearance as a product.

  The camera 71 is a laser camera that takes a picture using laser light.

  Thereby, since the shape of the deformation | transformation part 80 can be detected, without installing lighting equipment in a furnace, it is possible to suppress the raise in the cost in the case of applying this invention to the existing heating furnace 40. Become.

  In the above-described embodiment, the present invention is applied to the heating furnace 40 for brazing the heat exchanger W as a work to be heated. However, the present invention is not limited to this. For example, the present invention can be applied to a heating furnace that heats an object to be brazed other than the heat exchanger W.

  In the above embodiment, the present invention is applied to a heating furnace for brazing, but the present invention may be applied to a heating furnace used in a process for heating an object to be heated other than the brazing process. Good.

  In the above-described embodiment, the camera 71 including the laser camera is shown as the shape detection unit that detects the change in the shape of the deforming unit 80. However, the present invention is not limited to this. For example, a visible light camera or a radiation thermometer capable of outputting a detection signal as a two-dimensional image may be used as long as it can detect a change in the shape of the deforming unit 80.

  Moreover, although the said embodiment showed what provided the deformation | transformation part 80 in the refrigerant | coolant inflow tube 101a of the heat exchanger W as a heating object, it is not restricted to this. For example, a deforming portion may be provided in a portion other than the refrigerant inflow pipe 101a of the heat exchanger W, or the heat exchanger W is transported by the transport device 10 together with the heat exchanger W in the vicinity of the heat exchanger W as a separate body. A deformed portion may be provided.

  Moreover, in the said embodiment, the deformation | transformation part 80 is respectively arrange | positioned at intervals in the axial direction while extending in the circumferential direction of the refrigerant inflow pipe 101a, and a plurality of projecting pieces 80 projecting from the outer peripheral surface of the refrigerant inflow pipe 101a. Although what was set to -1 to n was shown, it is not restricted to this. The deforming part may be any part that changes its shape visually as a result of heating. For example, it may be a convex part that is flush with other planes as a result of heating, or may be other as a result of heating. It may be a recess that is flush with the flat surface.

  Moreover, in the said embodiment, although the deformation | transformation part 80 was formed from the solder | brazing | wax material which fuse | melts by heating and a shape changes, it was not restricted to this. As the deformation part, for example, a flux that is applied to the outer surface during brazing of the heat exchanger W and changes its state by heating may be used as the deformation part. In addition, the deformed part may be any part that changes its state visually due to changes in temperature, such as a solid that sublimates, a liquid that solidifies or evaporates. It is also possible to condense or solidify a gaseous substance.

  DESCRIPTION OF SYMBOLS 40 ... Heating furnace, 41 ... Electric heater, 70 ... Controller, 71-1 to n ... Camera, 80 ... Deformation part, 80-1 to n ... Projection piece, W ... Heat exchanger.

Claims (4)

A heating furnace equipped with a heater for heating a workpiece located in the furnace,
A deformed portion that is provided in the vicinity of the workpiece in the furnace or in the workpiece and changes its shape when heated to a predetermined temperature or higher,
Shape detecting means for detecting the shape of the deformed portion;
A heating furnace comprising: a workpiece temperature acquisition unit configured to acquire a workpiece temperature based on the shape of the deformed portion detected by the shape detection unit. The heating furnace according to claim 1, wherein the deformable portion is a member that melts when heated to a predetermined temperature or higher. The heating furnace according to claim 1 or 2, wherein the shape detection means is a camera that takes an image using laser light. A workpiece temperature acquisition method in a heating furnace for acquiring the temperature of a workpiece heated by a heater,
A deformed part whose shape changes when heated to a predetermined temperature or more is provided in the vicinity of the work in the furnace or in the work,
Detect the shape of the deformed part,
A workpiece temperature acquisition method in a heating furnace that acquires a workpiece temperature based on a detected shape of a deformed portion.

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