WELDING DEVICE

Abstract

A welding device is provided in which gas is drawn through suction ports in a first plate more uniformly than in a conventional device; a welding device according to this disclosure is a welding device for performing welding and includes a blower unit for supplying gas to an object; the blower unit includes: a first plate in which a plurality of suction ports are formed for drawing gas to the outside of the blower unit; a second plate having a plate surface facing the plurality of suction ports; a plurality of nozzles; and a fan for supplying the gas drawn through the plurality of suction ports to the plurality of nozzles;A flow path is formed through which the gas flows and extends from the plurality of suction ports to go through a heater and fan and to reach the plurality of nozzles in the blower unit; a portion of the flow path surrounds at least a portion of the second plate in directions in which the plate surface extends.

Description

WELDING DEVICE TECHNICAL FIELD The present invention relates to a welding device. BACKGROUND OF THE INVENTION To solder parts of electronic components onto a circuit board, a soldering device such as a reflow unit or a jet soldering station is used. For example, PTL 1 discloses a soldering device equipped with a heater unit. As shown in Figure 12, the heater unit includes a nozzle cover with suction ports, blow nozzles, and a blower. The gas drawn through the suction ports in the nozzle cover is expelled through the blow nozzles. Furthermore, as shown in Figure 10 of PTL 1, a rectangular mounting plate is positioned on the heater unit facing the suction ports in the nozzle cover. The suction ports are located near two opposite sides of the mounting plate, each extending along a different side.The suction ports in the mounting plate form part of the gas flow path provided to the inside of the heater unit. Therefore, when the heater unit is powered on, the gas drawn through the suction ports in the nozzle cover passes through the suction ports in the mounting plate. List of references Patent literature PTL 1: Japanese Patent No. 5541353 BRIEF DESCRIPTION OF THE INVENTION Technical problem In the welding device disclosed in PTL 1, the gas drawn through the suction ports in the nozzle cover must pass through the suction ports in the mounting plate to reach the blower. Furthermore, the distances between the suction ports in the nozzle cover and the suction ports in the mounting plate vary. Therefore, the gas flow rate drawn through certain suction ports in the nozzle cover (cj Aznn / eznz / E / YiAi) positioned closer to the suction ports in the mounting plate tends to be greater than the gas flow rate drawn through certain suction ports in the nozzle cover positioned farther from the suction ports in the mounting plate.As a result, if no countermeasure is taken regarding this situation, there is a possibility that the flow volumes of the gas extracted through the plurality of suction ports may not be uniform. To deal with this situation, one objective of the present disclosure is to provide a welding device in which gas is drawn through suction ports in a nozzle cover (suction ports on a first plate) more uniformly than in the conventional device. Solution to the problem A welding device according to this disclosure is a welding device for performing welding and includes a blower unit for supplying gas to an object, wherein the blower unit includes: a first plate in which a plurality of suction ports are formed for drawing gas away from the blower unit; a second plate having a plate surface facing the plurality of suction ports; a plurality of nozzles; and a fan for supplying the gas drawn through the plurality of suction ports to the plurality of nozzles, a flow path being formed through which the gas flows and extending from the plurality of suction ports to go through the fan and to reach the plurality of nozzles in the blower unit, and, a portion of the flow path surrounds at least a portion of the second plate in directions in which the plate surface extends. Advantageous effects of the invention In the welding device according to the present disclosure, the gas is drawn through the suction ports in the first plate more uniformly than in the conventional device. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a structural diagram of a reflux furnace according to a first modality of the present disclosure. Fig. 2 is a structural diagram of any of the blower units shown in Fig. 1. Fig. 3 is an arrow view taken in AA in Fig. 2. Fig. 4A is a cross-sectional view taken at BB in Fig. 2. cj βζηη / ρζηζ / Ε / γίΛΐ Fig. 4B is a cross-sectional view showing a portion of a mounting plate for a blower unit according to another embodiment of this disclosure. Fig. 5 is a cross-sectional view taken in CC in Fig. 2. Fig. 6 is an enlarged view of part E in Fig. 2. DETAILED DESCRIPTION OF THE INVENTION The embodiments of the present invention will now be described with reference to the drawings. In the drawings described below, some of the constituent elements that are identical or correspond to one another will be denoted by the same reference numbers, and a duplicate description of them will be omitted. First Modality General Settings Figure 1 is a cross-sectional view of a reflow oven 100 according to a first embodiment of the present disclosure. As shown in Figure 1, the reflow oven 100 includes a main body part 101 and a conveyor 102 that carries a substrate 200. The reflow oven 100 is a device for soldering an electronic component part onto the substrate 200 using a reflow method. In the reflow oven 100, although the substrate 200, onto which the electronic component part is placed via solder paste, is conveyed from an inlet 110 to an outlet 112, the electronic component part is soldered onto the substrate 200. In this situation, the reflow oven 100 is an example of the soldering device, while the substrate 200 is an example of the object. The reflow oven 100 will now be described in detail. A main body part 101 is divided into three zones: a preheating zone A, a main heating zone B, and a cooling zone C, in ascending order of distance from the inlet 110. Blower units 300a, five at the top and five at the bottom, are arranged in preheating zone A. These blower units supply hot gas to the substrate 200, heating it to between 150 and 180 degrees Celsius. As a result, the substrate 200 and the electronic component are preheated. In other words, preheating zone A is a region for slowly applying heat so that the substrate 200 and the electronic component mounted on it, or similar components, become acclimated to the heat. The detailed configurations of the blower units 300a will be described later. cj βζηη / ρζηζ / Ε / γίΛΐ The 300b blower units, three at the top and three at the bottom, are arranged in the main heating zone B. These units supply hot gas to the substrate 200, heating it to between 220 and 260 degrees Celsius. As a result, the 300b blower units melt the solder in the soldering paste, allowing the substrate 200 and the electronic component to be soldered together. In other words, the main heating zone B is a region for performing soldering by melting solder powder into the soldering paste. The blower units 300c, one at the top and one at the bottom, are arranged in cooling zone C. Using a known method, the blower units 300c blow cooled gas onto substrate 200 to cool the substrate 200 on which the welding was performed. In other words, cooling zone C is a region for cooling the substrate 200 on which the welding was performed. In other embodiments, the reflow oven 100 is not limited to the configuration described above and can adopt any publicly known configuration. For example, the interior of the reflow oven 100 according to the present embodiment can be filled with nitrogen in one instance, such that each of the blower units 300a, 300b, and 300c is capable of blowing nitrogen onto the substrate 200. However, in other embodiments, the interior of the reflow oven 100 can be filled with any gas known to a person skilled in the art. The blower units 300a, 300b, and 300c can be configured to blow any gas used by a person skilled in the art. Furthermore, although the reflow oven 100 according to the present embodiment includes the single-line conveyor 102, the reflow oven 100 in other embodiments can include a plurality of conveyors 102 arranged parallel to each other.In that situation, transporters 102 can transport substrate 200 independently of each other. Blower units The blower units 300a, 300b, and 300c will now be described, with reference to Fig. 2. The blower units 300a, 300b, and 300c have the same configurations as each other, except that the temperatures of the gas supplied in this way are different. For this reason, with reference to Fig. 2 through Fig. 6, blower units 300a, 300b, and 300c will be described, although reference is made to blower unit 300. Fig. 2 is a structural diagram of blower unit 300. In addition, Fig. 3 is an arrow view taken at AA in Fig. 2. Fig. 4A is a cross-sectional view taken at BB in Fig. 2. Fig. 5 is a cross-sectional view taken at CC in Fig. 2. Fig. 6 is a magnified view of part E in Fig. 2. Arrow 250 from Fig. 2 to Fig. 5 indicates the transport direction of substrate 200 in the reflow furnace 100. As shown in Fig. 2, in one example, the blower unit 300 includes an inner housing 320, an outer housing 360, a plurality of nozzles 420, a fan 302, a motor 304, a rotating shaft 306, a plurality of heaters 308, and two metal drilling pieces 310. The constituent elements of the blower unit 300 will be described below. The outer box 360 includes a main body of the outer box 362 and a nozzle cover 364, and houses the inner box 320. The main body of the outer box 362 is a box-like body with a substantially cuboid shape and an opening closed by the nozzle cover 364. The nozzle cover 364 has a plate portion (a first plate) 368 (see Fig. 3) with a rectangular plate-like shape and a rim portion 370 extending orthogonally from the plate portion 368. The rim portion 370 can be connected to the main body of the outer box 362 by fitting it to the plate portion. Therefore, the main body of the outer box 362 and the nozzle cover 364 integrally structure the substantially cuboid outer box 360.Furthermore, the main body of the outer box 362, a main body of the inner box 340, and a mounting plate 342 (described later) define a suction chamber 374 surrounded by the main body of the outer box 362, the main body of the inner box 340, and the mounting plate 342. The suction chamber 374 forms a first flow path 903 extending from a plurality of suction ports 366 (described later) to a gas intake port 332. As described earlier, in the present embodiment, the nozzle cover 364 has the rim portion 370; however, in other embodiments, the nozzle cover 364 need not have the rim portion 370. In those situations, a side wall 363 of the main body of the outer box 362 extends as far as the plate portion 368. In one example, a plurality of suction ports 366, each with an oblong orifice shape, are formed in plate portion 368 (see Fig. 3). These suction ports 366 allow communication between the exterior of the blower unit 300 and the suction chamber 374. As a result, gas outside the blower unit 300 can be drawn into the suction chamber 374 via these suction ports 366. In this configuration, the shape of each suction port 366 does not necessarily have to be an oblong orifice and can be any other shape, such as circular, polygonal, or similar. Furthermore, the suction ports 366 can be formed in any position on plate portion 368. In one example, inner box 320 includes the main body of inner box 340, mounting plate 342 (the second plate) and a mounting plate 343 (see Fig. 2). The main body of the inner box 340 is a prism-shaped tubular body having an opening cj closed by the fixing plate 342. Furthermore, the fixing plate 342 is a plate-type member having a plate surface 351 facing the plurality of suction ports 366 formed in the plate portion 368. Additionally, the main body of the inner box 340 and the fixing plate 342 define a blowing chamber 325 surrounded by the main body of the inner box 340 and the fixing plate 342. The blowing chamber 325 forms a second flow path 904 extending from the gas intake port 332 to the plurality of nozzles 420.More specifically, the main body of the inner box 340 includes a first wall 326, a second wall (the wall) 328, a first inner wall 330, and a second inner wall 331. The first wall 326, the second wall 328, the first inner wall 330, and the second inner wall 331 are each constructed with a plate-type member. The first wall 326 faces the fan 302 along the axial direction of the fan 302. The second wall 328 faces the first wall 326 and is positioned closer to the motor 304 than the first wall 326. Furthermore, the first inner wall 330 joins the first wall 326 and the second wall 328 together. The second inner wall 331 joins the first wall 326 and the mounting plate 342 together. In addition, the gas intake port 332 is formed in the second wall 328. Two outlet ports 334 are formed in the first wall 326 (see Fig. 2 and Fig. 5).Furthermore, the space enclosed by the first wall 326, the second wall 328, and the first inner wall 330 is a first blow chamber 322. Furthermore, the space enclosed by the first wall 326, the fixing plate 342, and the second inner wall 331 is a second blow chamber 324. In other words, the first wall 326 divides the blow chamber 325 into the first blow chamber 322 and the second blow chamber 324. Furthermore, the second blow chamber 324 houses the two metal perforating pieces 310. These two metal perforating pieces 310 extend parallel to the first wall 326. Consequently, the gas blown through the two outlet ports 334 is diffused by the metal perforating pieces 310, so that the flow volume is uniform between different positions in a plane perpendicular to the axial direction of the fan 302. As a result, the blower unit 300 is able to supply the gas in more uniform flow volumes to the supply ports 422 corresponding to the plurality of nozzles 420 (described later), compared to the situation where the metal perforating pieces 310 are not provided. As shown in Fig. 6, each of the nozzles 420 is a tubular body having: the supply port 422 through which gas is supplied into the blow chamber 325; and a blow port 424 used to expel gas to the outside of the blower unit 300. In addition, the nozzles 420 are fixed to the mounting plate 342. More specifically, each of the nozzles 420 has, as shown in Fig. 6, a main body portion 426 and an elongated diameter portion 428 having a larger outside diameter than that of the main body portion 426. cj βζηη / ρζηζ / Ε / γίΛΐ Furthermore, the mounting plate 342 is provided with a plurality of staggered holes 344 for the purpose of attaching the nozzles 420. The diameter of an opening 346 in the first step of each of the holes 344 corresponds to the outside diameter of the elongated diameter portion 428. The diameter of an opening 348 in the second step of each of the holes 344 corresponds to the outside diameter of the main body portion 426. With these arrangements, each of the nozzles 420 is secured to the mounting plate 342 as it penetrates the mounting plate 342, as a result of being inserted with the opening of the first step 346 into the mounting plate 342. Furthermore, the plurality of nozzles 420 are secured to the mounting plate 342 as a result of the mounting plate 343 pressing the plurality of nozzles 420 against the fixing plate 342.The mounting plate 343 is provided with holes 345 formed in positions corresponding to the nozzle positions 420. As a result, the gas in the blow chamber 325 is supplied to the supply ports 422 of the nozzles 420 via the holes 345. Regarding the method of attaching the nozzles 420 to the mounting plate 342, any configuration is possible that allows the gas in the blow chamber 325 to be supplied to the supply ports 422. For example, the plurality of nozzles 420 can be welded to the positions where the holes 344 are formed in the mounting plate 342, without passing through the holes 344, to allow communication between the supply ports 422 and the holes 344. Furthermore, the plurality of nozzles 420 goes through holes 372 formed in corresponding positions in the nozzle cover 364 of the outer case 360, to allow the blow ports 424 to communicate with the outside of the outer case 360 ​​(see Fig. 6). Consequently, the blow ports 424 of the nozzle plurality 420 are capable of venting gas to the outside of the blower unit 300. Regarding the method of attaching the nozzles 420 to the nozzle cover 364, any configuration is possible that enables the blow ports 424 of the nozzle plurality 420 to vent gas to the outside of the blower unit 300. For example, the nozzle plurality 420 can be welded to the positions where the holes 372 are formed in the nozzle cover 364, without passing through the holes 372, to allow communication between the blow ports 424 and the holes 372. Furthermore, in the blower unit 300, the substrate 200 is heated as a result of the gas being blown through the blow ports 424 of the plurality of nozzles 420 that come into contact with the substrate 200 (see Fig. 1). In this situation, the gas blown into substrate 200 can bounce off substrate 200, so the bouncing gas can interfere with the gas that has just been blown into substrate 200 through any of the blow ports 424. In that situation, the gas that bounces off substrate 200 has a lower temperature because some of the heat is absorbed by substrate 200. Thus, this situation is not preferable, because the temperature of the gas blown through the blow ports 424 can be reduced in this way, and also, the blowing directions of the gas blown through the blow ports 424 can be altered in this way. However, the blower unit 300 is able to reduce occurrences where gas rebounding off the substrate 200 lowers the temperature of the gas just blown through the blow ports 424 or alters the blowing directions of the gas blown through the blow ports 424. This is because, in the blower unit 300, as shown in Fig. 3, the blow ports 424 of the nozzle plurality 420 are positioned adjacent to the suction ports 366. Consequently, the gas rebounding off the substrate 200 is immediately drawn out through the suction ports 366. As a result, it is possible to reduce occurrences where rebounding gas lowers the temperature of the gas blown through the blow ports 424 or obstructs the gas blown through the blow ports 424. Returning to the description in Fig. 2, the fan 302 is a turbo fan housed in the first blow chamber 322, in this example. The fan 302 is connected to the motor 304 located outside the outer casing 360 via the rotating shaft 306, which transmits the rotation. In other words, the rotating shaft 306 extends between the fan 302 and the motor 304, passing through the gas intake port 332. Consequently, when the motor 304 is driven, the fan 302 rotates and is able to blow the gas in centrifugal directions. Furthermore, the wind caused by the rotation of the fan 302 collides with the first inner wall 330 of the main body of the inner box 340, and changes its flow direction through the first inner wall 330, to be sent to the second blow chamber 324 through the two outlet ports 334 formed in the first wall 326.Furthermore, the gas sent to the second blow chamber 324 passes through the second blow chamber 324 and is supplied to the plurality of nozzles 420. In other words, as a result of the rotation of the fan 302, the gas flows through the plurality of suction ports 366 to the plurality of nozzles 420. Thus, the fan 302 has the function of supplying the gas drawn through the plurality of suction ports 366 to the plurality of nozzles 420. Furthermore, in one example, the 308 heaters are housed in the 374 suction chamber and have a gas heating function capable of reaching any temperature. Specifically, when the 300 blower unit is used for melting solder, such as the 300b blower unit provided in the main heating zone B, it is preferable to configure the 308 heaters to heat the gas to 220 degrees Celsius or higher. The melting point of lead-free solder in soldering paste is approximately 217 degrees Celsius, for example. Therefore, the 308 heaters, which have the function of heating the gas to 220 degrees Celsius or higher, are capable of heating the gas to a temperature at which lead-free solder melts. In other embodiments, the 308 heaters can be provided in other positions such as inside the 325 blow chamber or similar.However, as described later, it is preferable to have the 308 heaters positioned between the 304 motor and the 302 fan, like the 308a heaters. Consequently, in the 300 blower unit, some of the 308 heaters, such as the 308a heaters, are positioned between the 304 motor and the 302 fan (see Fig. 2). Furthermore, when the 300 blower unit is used to cool the 200 substrate, as in the 300c blower unit, the 300 blower unit may include a known cooling unit used for cooling gas, such as a heat exchanger, instead of the 308 heaters. Furthermore, in the blower unit 300, a flow path 905 is formed to extend from the plurality of suction ports 366, through the heaters 308 and the fan 302, and to reach the plurality of nozzles 420. Each of the first flow path 903 and the second flow path 904 described above are part of the flow path 905. In this situation, as shown in Fig. 4A, a portion of the flow path 905 surrounds, without any gap, a peripheral end portion 347 of the mounting plate 342, i.e., the entirety of the mounting plate 342 in directions in which the plate surface 351 extends. In other words, a portion of the flow path 905 is formed to pass through an opening 349 formed between the peripheral end portion 347 of the mounting plate 342 and the outer casing. 360.Therefore, the blower unit 300 is able to draw gas evenly through the plurality of suction ports 366. The reasons for this will be described below. With regard to blower units such as blower unit 300, which includes: the plate portion 368 in which the plurality of suction ports 366 are formed; and the fixing plate 342 having the plate surface 351 facing the plurality of suction ports 366, the flow volumes of the gas drawn through the suction ports 366 may be impacted by the structure of the flow path in which the gas drawn through the suction ports 366 flows. For this reason, depending on the structure of the flow path, there is a possibility that the gas may not be drawn uniformly through the plurality of suction ports 366. For example, as in the heater unit disclosed in PTL 1, when openings are formed in the vicinity of two opposite sides of a rectangular mounting plate, each extending along a different side, and these openings serve as flow paths for the gas drawn through a plurality of suction ports, there is a possibility that the gas may not be drawn uniformly through the plurality of suction ports. This is because it is easier for the gas to be drawn through suction ports facing the openings formed in the mounting plate and positioned closer to the openings, whereas it is more difficult for the gas to be drawn through suction ports facing an intermediate point between any two openings formed in the mounting plate and positioned farther from each of the openings.In other words, regarding the displacement distances of the gas drawn through the suction ports and traveling from the suction ports to reach the openings, there is a difference in displacement distance between the gas drawn through suction ports located closer to the openings and the gas drawn through suction ports located farther from the openings. Consequently, the flow volumes of the gas drawn through the suction ports tend to be non-uniform. In contrast, in blower unit 300, a portion of the flow path 905 surrounds the peripheral end portion 347 of the mounting plate 342, i.e., the entire mounting plate 342 (see Fig. 4A). Consequently, the total area of ​​the opening 349 is larger, and the number of positions serving as the opening 349 is also greater, compared to the example described earlier. As a result, the total volume of gas drawn through the suction ports 366 located farther from the opening 349 is larger, and the difference in displacement distance is not easily caused between the gas drawn through the suction ports 366 and the displacement from the suction ports 366 to reach the opening 349. Consequently, blower unit 300 is able to draw gas uniformly through the plurality of suction ports 366. Figure 4B is a cross-sectional view showing a portion of the mounting plate 342 of a blower unit 301 according to another embodiment of this disclosure. In Figure 4B, four rectangular openings 349a, 349b, 349c, and 349d are formed in the vicinity of the four sides of the rectangular mounting plate 342, each extending along a different side. A portion of the flow path 905 is formed to pass through the openings 349a, 349b, 349c, and 349d. In other words, a portion of the flow path 905 surrounds a partial region 350 of the mounting plate 342 in directions in which the plate surface 351 of the mounting plate 342 extends.In this situation as well, as in the blower unit 300 described above, the total area of ​​the openings 349a, 349b, 349c, and 349d is larger, and the number of positions serving as openings 349a, 349b, 349c, and 349d is also larger, compared to the example disclosed in PTL 1. As a result, as in the blower unit 300, the blower unit 301 is able to draw gas uniformly through the plurality of suction ports 366. In other words, to enable the blower unit 301 to draw gas through the plurality of suction ports 366 more uniformly than in the example disclosed in PTL 1, it is sufficient when a portion of the flow path 905 surrounds at least a portion of the mounting plate 342, and there is no need to surround the peripheral end portion. 347 without a gap.In the present description, the configuration in which a portion of the flow path 905 surrounds at least a portion of the mounting plate 342 denotes that the flow path 905 is partially positioned in at least four directions from a certain point within at least a portion of the mounting plate 342. More specifically, the configuration denotes that the flow path 905 is partially positioned in at least four locations that are at 90-degree intervals centered on the certain point. Furthermore, in the blower unit 301, in one example, the plurality of nozzles 420 is fixed within the area of ​​region 350 of the mounting plate 342. Furthermore, as described earlier, in the blower unit 300, each of the suction ports 366 can be of any shape and can be arranged in any position on the plate portion 368 (see Fig. 3). However, it is preferable to configure the cross-sectional area of ​​the suction ports 366 located farther from the openings 349 to be larger than the cross-sectional areas of the suction ports 366 located closer to the opening 349. In other words, it is preferable to configure the suction ports 366 such that their cross-sectional area increases as their distance from the center of the plate portion 368 of the nozzle cover 364 decreases.Consequently, in the blower unit 300, the suction ports 366 located closer to the opening 349, through which gas is most easily drawn, experience a greater pressure loss than the suction ports 366 located farther from the opening 349. As a result, when the blower unit 300 draws gas through the plurality of suction ports 366, these ports are able to draw gas in a well-balanced manner. Furthermore, in this description, the distance between each of the suction ports 366 and the opening 349 denotes the distance between the suction ports 366 and the opening 349 at their closest positions. Furthermore, as shown in Fig. 1, in the reflow furnace 100, the plurality of blower units 300 are arranged side by side along the transport direction 250 of the substrate 200. In this situation, when the interval between the nozzles 420 belonging to any two adjacent blower units 300 is too long, gas may not be supplied from the blower units 300 to the substrate 200 for an extended period. In particular, when the blower units 300 supply hot gas to the substrate 200, the temperature of the substrate 200 may drop, which is undesirable. To address this situation, as shown in Fig.4A, in blower units 300, for example, the opening 349 has a rectangular annular cross-sectional shape, and has two first sections 352 positioned at the front and rear in the transport direction 250 and two second sections 353 positioned to the left and right in the transport direction 250. In other words, of the opening 349, each of the first sections 352 is a section extending in the direction orthogonal to the transport direction 250. Furthermore, of the opening 349, each of the second sections 353 is a section extending in the transport direction 250. Moreover, the width dimension L1 of each of the first sections 352 extending in the transport direction 250 is smaller than the width dimension L2 of each of the second sections 353 that extend in the direction orthogonal to the transport direction 250.With this configuration, in the reflow oven 100, the nozzles 420 belonging to any two blower units 300 can be arranged adjacent to each other so as not to have a long gap between them, without reducing the cross-sectional area of ​​the entire opening 349. As a result, the reflow oven 100 is able to prevent the temperature of the substrate 200 from dropping by shortening the period of time during which no gas is supplied to the substrate 200. Furthermore, in another embodiment, the width dimension L1 of each of the first sections 352 extending in the conveying direction 250 and the width dimension L2 of each of the second sections 353 extending orthogonally to the conveying direction 250 are not particularly restricted. For example, the width dimension L1 can be equal to the width dimension L2 or it can be larger than the width dimension L2. Furthermore, in blower units in general, when the internal flow path structure becomes complex, such that the flow path meanders or has a narrow cross-sectional area, the pressure loss of the gas flowing through the flow path increases. For this reason, the internal flow path structure of blower units is important, and there is a demand for blower units whose design can be detailed to avoid complicating their flow path structure. As described earlier, one of the features of the 300 blower units is that a portion of the flow path 905 surrounds the peripheral end portion 347 of the mounting plate 342. If the flow path structure of the heater unit disclosed in PTL 1 were applied to blower units having this feature, the flow path structure could be complicated, which is undesirable. The reasons for this are described below. In the heater unit disclosed in PTL 1, as shown in Fig. 12 therein, the gas is supplied from a heat exchange chamber located directly below the blower to a blow chamber. Furthermore, the gas is supplied from the blow chamber to the blow nozzles attached to the mounting plate located below the heat exchange chamber. Therefore, to apply the flow path structure of the heater unit disclosed in PTL 1 to the blower unit having the aforementioned feature, it might be necessary to form a flow path to guide the gas that has flowed around the peripheral end portion of the mounting plate to the heat exchange chamber located directly below the blower.If the flow path were formed in this way, this flow path and the flow path that guides the gas from the blow chamber to the blow nozzles could compete with each other for space inside the blower unit, which could complicate the flow path structure and increase pressure loss. In contrast, in the blower unit 300 according to the present embodiment, in a cross-sectional plane parallel to the mounting plate 342, the first flow path 903 is positioned to surround the blow chamber 325 (see Fig. 2 and Fig. 5). Consequently, the gas that has passed around the peripheral end portion 347 of the mounting plate 342 flows through the first flow path 903, which is positioned to surround the blow chamber 325, and is thus able to flow to the gas intake port 332. In this configuration, it is possible to design the portion of the first flow path 903 that surrounds the blow chamber 325 in a shape (e.g., a linear shape) that results in a small pressure drop.In other words, the design of the blower units 300 can be detailed so that the first flow path 903, extending from the plurality of suction ports 366 to the gas intake port 332, does not become complicated. Therefore, it is possible to reduce the pressure loss in the first flow path 903, which could be caused by complicating the first flow path 903. Furthermore, the soldering paste used in soldering contains a flux. During soldering, the flux is heated and vaporized. For this reason, the gas inside the reflow oven 100 contains the vaporized flux. Additionally, as it flows into the blower unit 300, when the flux-containing gas comes into contact with a low-temperature component, there is a possibility that the flux may be cooled and adhere as an adhesive solid to the low-temperature component. In the blower units 300, the fan 302 is housed in the first blow chamber 322 located on the downstream side of the suction chamber 374 that houses the heaters 308 therein (see Fig. 2). Consequently, the gas drawn into the suction chamber 374 passes through the first flow path 903 and is heated by the heaters 308 before being applied to the fan 302 housed in the first blow chamber 322. In other words, the gas that has just been heated by the heaters 308 comes into contact with the fan 302. For this reason, since the gas coming into contact with the fan 302 is at a high temperature, the flux contained in the gas is prevented from adhering to the fan 302 in the blower units 300. Furthermore, in the blower units 300, some of the heaters 308, such as heaters 308a, are positioned between the motor 304 and the fan 302 (see Fig. 2).Consequently, it is possible to position the 308a heaters close to the 306 rotating shaft, which allows the gas surrounding the 306 rotating shaft to be heated to a higher temperature. As a result, even when the flux-containing gas comes into contact with the 306 rotating shaft, the flux does not cool to a temperature that would cause adhesion. Therefore, it is possible to prevent the flux from adhering to the 306 rotating shaft. Furthermore, the 302 fan is configured to draw gas along the axial direction, from the side where the 304 motor is located. Consequently, the gas heated by the 308a heaters flows through the space between the 304 motor and the 302 fan and is close to the 306 rotating shaft. As a result, since the 306 rotating shaft is heated by the hot gas, the flux is prevented from adhering to it. Operations The operation of any of the blower units 300 in the reflow oven 100 will now be described, with reference to Fig. 2. When the power supply for blower unit 300 is switched on, the motor 304 is driven, and the fan 302 begins to rotate. Thus, the upstream side of the fan 302 is under negative pressure. As a result, the gas outside the outer casing 360 and inside the reflow oven 100 is drawn into the outer casing 360 through the suction ports 366 (see Fig. 1 and Fig. 2). Subsequently, the drawn gas is heated by the heaters 308 inside the outer casing 360. After that, the gas heated by heaters 308 is drawn into the inner chamber 320 via gas intake port 332. Subsequently, the drawn gas inside the inner chamber 320 is blown centrifugally by fan 302. The gas blown by fan 302 then strikes the first inner wall 330 and is directed to the second blow chamber 324 through the two outlet ports 334. The gas that has passed through the two outlet ports 334 then diffuses through the two metal perforating pieces 310 and is supplied to the supply ports 422 of the nozzles 420. Finally, the gas is discharged through the blow ports 424 of the nozzles 420. In this way, the blower units 300 are able to supply heated air to the substrate. 200. As a result, the reflow oven 100 described above is capable of performing the welding. Supplements Some or all of the above-described modalities may also be described as presented in the following Supplements, but are not limited to these examples. Supplement 1 A welding device according to Supplement 1 is a welding device for performing welding and includes a blower unit for supplying gas to an object, wherein the blower unit includes: a first plate in which a plurality of suction ports are formed for drawing gas away from the blower unit; a second plate having a plate surface facing the plurality of suction ports; a plurality of nozzles;and a fan to supply the drawn gas through the plurality of suction ports to the plurality of nozzles, a flow path is formed through which the gas flows and extending from the plurality of suction ports to go through the fan and to reach the plurality of nozzles in the blower unit, and a portion of the flow path surrounds at least a portion of the second plate in directions in which the plate surface extends. For example, when openings are formed in the vicinity of two opposite sides of the second rectangular plate, each extending along a different side, so that the openings serve as a flow path for the gas drawn through the plurality of suction ports, there is a possibility that the gas might not be drawn uniformly through the plurality of suction ports. This is because it is easier for the gas to be drawn through the suction ports facing the openings formed in the second plate and positioned closer to them, while it is more difficult for the gas to be drawn through the suction ports facing an intermediate point between any two openings formed in the second plate and positioned farther from each opening.In other words, regarding the displacement distances of the gas drawn through the suction ports and traveling from the suction ports to reach the openings, there is a difference in displacement distance between the gas drawn through the suction ports located closer to the openings and the gas drawn through the suction ports located farther away. Consequently, the flow volumes of the gas drawn through the suction ports tend to be non-uniform. In contrast, in the welding device according to Supplement 1, a portion of the flow path surrounds at least a portion of the second plate. Consequently, compared to the example described earlier, the total area of ​​the opening is larger, and the number of positions serving as the opening is also greater.As a result, the total volume of gas drawn through the suction ports located closer to the opening is greater, and the difference in travel distance between the gas drawn through the suction ports and the distance it travels from the suction ports to reach the opening is not easily caused. Therefore, the welding device is able to draw gas uniformly through the multiple suction ports. Supplement 2 A welding device according to Supplement 2 is the welding device according to Supplement 1 in which the blower unit has an outer casing that includes the first plate, and a portion of the flux path is formed to go through an opening that is either formed between a peripheral end portion of the second plate and the outer casing or formed in the second plate. In the welding device according to Supplement 2, the gas is able to flow through the opening formed either between the peripheral end portion of the second plate and the outer case or in the second plate. Supplement 3 A welding device according to Supplement 3 is the welding device according to Supplement 2 wherein the blower unit further includes an inner box main body having a wall facing the second plate; the inner box main body and the second plate define a blowing chamber surrounded by the inner box main body and the second plate; the outer box, the inner box main body, and the second plate define a suction chamber surrounded by the outer box, the inner box main body, and the second plate; a gas inlet port to allow communication between the blowing chamber and the suction chamber is formed in the wall; the plurality of nozzles have supply ports through which gas is supplied into the blowing chamber;Within the suction chamber, a first flow path, which is a part of the flow path, is formed to extend from the plurality of suction ports to the gas intake port; and in a cross-sectional plane parallel to the second plate, the first flow path is positioned to surround the blow chamber. In the welding device according to Supplement 3, the first flow path is positioned to surround the blow chamber, in the cross-sectional plane parallel to the second plate. Consequently, the gas that has passed through the vicinity of the peripheral end portion of the second plate flows through the first flow path, which is positioned to surround the blow chamber, and is thus able to flow to the gas inlet port. In this configuration, it is possible to design the portion of the first flow path that surrounds the blow chamber in a shape (e.g., a linear shape) that results in a small pressure loss. In other words, it is possible to detail the design of the welding device so that the first flow path, which extends from the plurality of suction ports to the gas inlet port, does not become complicated.Therefore, it is possible to reduce the pressure loss in the first flow path, which could be caused if the first flow path were complicated. cj βζηη / ρζηζ / Ε / γίΛΐ Supplement 4 A welding device according to Supplement 4 is the welding device according to Supplement 3 in which, within the blow chamber, a second flow path is formed which is a part of the flow path to extend from the gas intake port to the plurality of nozzles. In the welding device according to Supplement 4, the gas that has passed through the gas intake port is supplied to the plurality of nozzles by going through the second flow path different from the first flow path. Supplement 5 A welding device according to Supplement 5 is the welding device according to any of Supplements 1 to 4 in which the plurality of nozzles have blow ports for throwing the gas to an outside of the blower unit, and the blow ports are positioned adjacent to the suction ports. As a result of the gas blown through the blow ports of the plurality of nozzles coming into contact with the substrate, the substrate is heated. In such a case, the gas blown onto the substrate may rebound, and this rebounding gas can interfere with the gas that has just been blown onto the substrate through the blow ports. In this situation, the gas that rebounds off the substrate has a lower temperature because some of the heat is absorbed by the substrate, and it may, in some situations, be lower than the temperature of the gas blown through the blow ports or alter the direction of the gas blown through the blow ports.To address these situations, in the welding device according to Supplement 5, it is possible to reduce the occurrence of gas rebound from the substrate, which lowers the temperature of the gas blown through the blow ports or alters the direction of gas flow. This is because, in the present welding device, the blow ports of the nozzles are positioned adjacent to the suction ports. Consequently, the gas rebounding from the substrate is immediately drawn through the suction ports. As a result, it is possible to reduce the occurrence of gas rebound that lowers the temperature of the gas blown through the blow ports or obstructs the flow of gas through them. Supplement 6 A welding device according to Supplement 6 is a welding device according to any of Supplements 1 to 5 in which the blower unit further includes a heater for heating the gas. By using the welding device in accordance with Supplement 6, it is possible to supply the hot gas from the heater to the object. cj βζηη / ρζηζ / Ε / γίΛΐ Supplement 7 A welding device according to Supplement 7 is the welding device according to Supplement 6 in which the blower unit further includes a motor and a rotating shaft for transmitting rotation from the motor to the fan, while the heater is positioned between the motor and the fan. In the welding device according to Supplement 7, the heater can be positioned near the axis of rotation to heat the gas surrounding the axis to a higher temperature. As a result, even when the flux-containing gas comes into contact with the axis of rotation, the flux does not cool to a temperature that causes adhesion. Therefore, it is possible to prevent the flux from adhering to the axis of rotation. Supplement 8 A welding device according to Supplement 8 is the welding device according to Supplement 7 in which the fan is configured to draw the gas along an axial direction, from one side on which the motor is placed. In the welding device according to Supplement 8, the gas heated by the heater flows through the space located near the rotating shaft, which extends between the motor and the fan. Consequently, since the rotating shaft is heated by the hot gas, it is possible to prevent the flux from adhering to it. Supplement 9 A welding device in accordance with Supplement 9 is a welding device in accordance with any of Supplements 6 to 8 in which the heater heats the gas to be equal to or greater than 220 degrees. By using the soldering device in accordance with Supplement 9, it is possible to blow the gas heated by the heater to a temperature of 220 degrees or higher onto the substrate to which the soldering paste has been applied. Furthermore, the melting point of the lead-free solder contained in the soldering paste is approximately 217 degrees. In other words, the soldering device is capable of melting the lead-free solder contained in the soldering paste by using gas heated by the heater to a temperature of 220 degrees or higher. Supplement 10 A welding device according to Supplement 10 is the welding device according to any of Supplements 6 to 9 dependent on Supplement 3 or 4 in which the blowing chamber houses the fan, and the suction chamber houses the heater. cj βζηη / ρζηζ / Ε / γίΛΐ In the welding device according to Supplement 10, the fan is housed in the blow chamber located downstream of the suction chamber that houses the heater. Consequently, the gas heated by the heater in the suction chamber is supplied to the fan in the blow chamber. In other words, the gas heated by the heater comes into contact with the fan. As a result, since the gas in contact with the fan is at a high temperature, the welding device is able to prevent the flux contained in the gas from adhering to the fan. Supplement 11 A welding device according to Supplement 11 is the welding device according to Supplement 2 or any of Supplements 3 to 10 dependent on Supplement 2, further including two blower units, each blower unit arranged side by side along a transport direction from the object, the two blower units being adjacent to each other, the opening having a rectangular annular cross-section shape, and having two first sections positioned at the front and rear in the transport direction and two second sections positioned to the left and right in the transport direction, and a width dimension of each of the first sections extending in the transport direction being smaller than a width dimension of each of the second sections extending in a direction orthogonal to the transport direction. In the welding device according to Supplement 11, the nozzles belonging to any two blower units can be arranged adjacent to each other so as not to have a long gap between them, without reducing the overall cross-sectional area of ​​the opening. As a result, the welding device is able to shorten the period of time during which no gas is supplied to the substrate. Supplement 12 A welding device according to Supplement 12 is the welding device according to Supplement 2 or any of Supplements 3 to 10 dependent on Supplement 2 in which, among the plurality of suction ports, the cross-sectional areas of the suction ports located farther from the opening are larger than the cross-sectional areas of the suction ports located closer to the opening. In the welding device according to Supplement 12, when the gas is drawn through the plurality of suction ports, the plurality of suction ports is able to draw the gas through them in a well-balanced manner. The embodiments of the present invention and examples of modifications thereof have been described. However, it is unnecessary to state that the aforementioned examples are intended to facilitate understanding of the present invention and are not intended to limit it. The present invention may be changed or improved as appropriate without departing from its essence, and the present invention includes equivalents thereof. Furthermore, any of the constituent elements set forth in the claims and description may be arbitrarily combined or omitted, to the extent possible to solve at least some of the aforementioned problems or to the extent possible to achieve at least some of the advantageous effects. List of reference signs 100: Reflux oven 200: Substrate 300: Blower Unit 302: Fan 304: Engine 306: Rotation axis 308: Heater 320: Inner box 325: Blow chamber 332: Gas intake port 334: Port of departure 340: Main body of the inner box 342: Fixing plate (second plate) 347: Peripheral end part 360: Outer box 362: Main body of the outer box 364: Nozzle cover 366: Suction port 368: Plate part (first plate) 370: Edge section 374: Suction chamber 420: Nozzle 422: Supply Port 424: Blow-off port 903: First flow path 904: Second flow path cj βζηη / ρζηζ / Ε / γίΛΐ 905: Flow path

Claims

1. A welding device for performing welding, the welding device comprising a blower unit for supplying gas to an object, wherein the blower unit includes: a first plate in which a plurality of suction ports are formed for drawing the gas to the outside of the blower unit; a second plate having a plate surface facing the plurality of suction ports; a plurality of nozzles;and a fan to supply the gas drawn through the plurality of suction ports to the plurality of nozzles, a flow path is formed through which the gas flows and extending from the plurality of suction ports to go through the fan and to reach the plurality of nozzles in the blower unit, the flow path being partially positioned at least in four positions that are at 90-degree intervals centered on a point within the second plate in directions in which the plate surface extends, a part of the flow path is formed to go through four openings formed respectively in the four positions of the second plate.

2. The welding device according to claim 1, further characterized in that the blower unit has an outer casing that includes the first plate.

3. The welding device according to claim 2, further characterized in that the blower unit additionally includes a main body of the inner box having a wall facing the second plate, the main body of the inner box and the second plate defining a blowing chamber surrounded by the main body of the inner box and the second plate, the outer box, the main body of the inner box, and the second plate defining a suction chamber surrounded by the outer box, the main body of the inner box, and the second plate, a gas inlet port being formed to allow communication between the blowing chamber and the suction chamber in the wall, the plurality of nozzles having supply ports through which gas is supplied into the blowing chamber, within the suction chamber,A first flow path is formed which is a part of the flow path to extend from the plurality of suction ports to the gas intake port, and in a cross-sectional plane parallel to the second plate, the first flow path is positioned to surround the blow chamber.

4. The welding device according to claim 3, further characterized in that within the blow chamber, a second flow path is formed which is a part of the flow path extending from the gas intake port to the plurality of nozzles. cj βζηη / ρζηζ / E / γίΛΐ 5. The welding device according to any of claims 1 to 4, further characterized in that the plurality of nozzles have blow ports for blowing the gas to an outside of the blower unit, and the blow ports are positioned adjacent to the suction ports.

6. The welding device according to any of claims 1 to 5, further characterized in that the blower unit additionally includes a heater for heating the gas.

7. The welding device according to claim 6, further characterized in that the blower unit additionally includes: a motor; and a rotating shaft for transmitting rotation from the motor to the fan, and the heater is placed between the motor and the fan.

8. The welding device according to claim 7, further characterized in that the fan is configured to extract the gas along an axial direction, from one side on which the motor is located.

9. The welding device according to any of claims 6 to 8, further characterized in that the heater heats the gas to be equal to or greater than 220 degrees.

10. The welding device according to any of claims 6 to 9, further characterized in that the blowing chamber houses the fan, and the suction chamber houses the heater.

11. The welding device according to any of claims 1 to 10, further characterized in that it additionally comprises: two blower units, each being the blower unit and arranged side by side along a transport direction of the object, the two blower units being adjacent to each other, wherein the four openings have two first sections positioned at the front and rear in the transport direction and two second sections positioned to the left and right in the transport direction, and a width dimension of each of the first sections extending in the transport direction is smaller than a width dimension of each of the second sections extending in a direction orthogonal to the transport direction.

12. The welding device according to any of claims 1 to 11, further characterized in that among the plurality of suction ports, the cross-sectional areas of the suction ports located furthest from the four openings are larger than the cross-sectional areas of the suction ports located closer to the four openings.

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