Heat Treatment Equipment

Abstract

To provide a heat processing device in which the overall configuration of the heat processing device capable of forming a swirling flow for cooling a workpiece may be shortened, components for forming a swirling flow in a cooling tank may be manufactured in a simple structure, and the components for forming the swirling flow may be easily installed in the device.SOLUTION: A heat processing device 1 is equipped with a cylindrical cooling tank 13 in which a workpiece 10 is placed, and an introduction tube 14 for introducing a refrigerant into the cooling tank 13 for a heat treatment of the workpiece 10. The introduction tube 14 includes a conversion member 21 that changes the direction of the flow of the refrigerant at an end of the side connected to the cooling tank 13 and forms a flow of the refrigerant swirling along the circumferential direction of the cooling tank 13. The conversion member 21 extends along the longitudinal direction of the cooling tank 13 between the bottom and top sides of the introduction tube 14, and has a curved surface (25a, 26a, 27a) along the inner shape of the cooling tank 13 as viewed from the longitudinal direction of the cooling tank 13.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a heat treatment apparatus that supplies a coolant to a workpiece to perform a heat treatment. [Background technology]

[0002] As a heat treatment apparatus that supplies a refrigerant to a workpiece to perform heat treatment, a heat treatment apparatus is known that places the workpiece in a cylindrical cooling tank and introduces the refrigerant into the cooling tank to create a swirling flow within the cooling tank, thereby uniformly cooling the workpiece (see, for example, Patent Documents 1 to 3).

[0003] The heat treatment apparatus described in Patent Document 1 is configured such that a steel pipe W as an object to be treated is placed inside a cylindrical cover 3 serving as a cooling tank, and a refrigerant is introduced into the cover 3 to perform heat treatment on the steel pipe W. A steel pipe support plate 5 that supports the steel pipe W is provided inside the cylindrical cover 3. The steel pipe support plate 5 is attached in close contact with the inner periphery of the cover 3 and is provided so as to extend spirally along the inner periphery of the cover 3. The heat treatment apparatus of Patent Document 1 is configured such that the steel pipe support plate 5 causes the flow of the refrigerant introduced into the cover 3 to become a swirling flow along the outer periphery of the steel pipe W inside the cover 3, thereby uniformly cooling the steel pipe W.

[0004] The heat treatment device described in Patent Document 2 is configured such that a steel pipe 1 as a workpiece is placed inside a cylindrical cover serving as a cooling tank, and a refrigerant is introduced into the cylindrical cover to perform heat treatment on the steel pipe 1. An upper rectifying plate 4 and a lower rectifying plate 5 are provided inside the cylindrical cover. The upper rectifying plate 4 and the lower rectifying plate 5 are attached in close contact with the inner periphery of the cylindrical cover and are provided so as to extend spirally along the inner periphery of the cylindrical cover. The heat treatment device of Patent Document 2 is configured such that the upper rectifying plate 4 and the lower rectifying plate 5 convert the flow of the refrigerant introduced into the cylindrical cover into a swirling flow that flows spirally around the outer surface of the steel pipe 1 inside the cylindrical cover, thereby uniformly cooling the steel pipe 1.

[0005] The heat treatment apparatus described in Patent Document 3 has a swirling flow generating section 19 immersed in a storage tank 12, a workpiece 1 as a treatment object is placed inside the swirling flow generating section 19, and is configured to heat treat the workpiece 1 by introducing a refrigerant into the swirling flow generating section 19. The swirling flow generating section 19 has a cylindrical wall section 21 as a cooling tank in which the workpiece 1 is placed, and the cylindrical wall section 21 is provided with a spiral groove 22 that extends spirally along the inner circumference of the wall section 21. The heat treatment apparatus of Patent Document 3 is configured so that the spiral groove 22 causes the flow of the refrigerant introduced into the wall section 21 to become a swirling flow that flows around the workpiece 1 inside the cylindrical wall section 21, thereby uniformly cooling the workpiece 1. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-84172 [Patent Document 2] Japanese Patent Application Laid-Open No. 2018-162480 [Patent Document 3] Japanese Patent Application Laid-Open No. 2015-160992 Summary of the Invention [Problem to be solved by the invention]

[0007] In the heat treatment devices disclosed in Patent Documents 1 to 3, when a refrigerant is introduced into a cooling tank and the flow of the refrigerant flowing in the cooling tank is made into a swirling flow, it is necessary to provide a structure that extends spirally along the inner periphery of the cooling tank. Therefore, in the heat treatment devices disclosed in Patent Documents 1 to 3, it is necessary to provide a structure that extends spirally along the longitudinal direction of the cooling tank to form a swirling flow, which increases the length of the cooling tank and the overall configuration of the heat treatment device.

[0008] Furthermore, in the heat treatment devices disclosed in Patent Documents 1 and 2, a plate-like, three-dimensional component extending spirally along the inner circumference of a cylindrical cooling tank is required to form a swirling flow. Furthermore, in the heat treatment device disclosed in Patent Document 3, a three-dimensional component having a spiral groove extending spirally along the inner circumference of the cylindrical wall is required to form a swirling flow. Furthermore, in the heat treatment devices disclosed in Patent Documents 1 and 2, the component for forming the swirling flow is installed inside the cylindrical cooling tank, extending spirally along the inner circumference of the cooling tank and closely attached to the inner circumference of the cooling tank. Therefore, the heat treatment devices disclosed in Patent Documents 1 and 2 have a problem in that it is not easy to fix a three-dimensional spiral component within the heat treatment device to form a swirling flow.

[0009] In view of the above circumstances, the present invention aims to provide a heat treatment device capable of forming a swirling flow for cooling a workpiece, which can shorten the overall structure of the heat treatment device, which can manufacture components for forming a swirling flow in a cooling tank with a simple structure, and which can easily install components for forming a swirling flow within the device. [Means for solving the problem]

[0010] (1) To solve the above-mentioned problems, a heat treatment apparatus according to one aspect of the present invention includes a cylindrical cooling tank in which a workpiece is placed, and an inlet pipe for introducing a refrigerant for heat treatment of the workpiece into the cooling tank, the cooling tank and the inlet pipe being connected in a direction different from the longitudinal direction of the cooling tank. In the heat treatment apparatus according to one aspect of the present invention, the inlet pipe includes a converting member at an end connected to the cooling tank that changes the flow direction of the refrigerant and causes the refrigerant flow to rotate circumferentially around the cooling tank, the converting member extending along the longitudinal direction of the cooling tank from the bottom side to the top side of the inlet pipe and having a curved or bent surface that follows the inner circumferential shape of the cooling tank when viewed from the longitudinal direction of the cooling tank.

[0011] According to this configuration, the refrigerant supplied to the inlet pipe flows through the inlet pipe and reaches the conversion member disposed at the end of the inlet pipe connected to the cooling tank. The refrigerant that reaches the conversion member flows along the surface of the conversion member, which extends along the longitudinal direction of the cooling tank from the bottom side to the top side of the inlet pipe, changing its flow direction from the longitudinal direction of the inlet pipe to the longitudinal direction of the cooling tank. Furthermore, the refrigerant flows along a curved or bent surface that conforms to the inner circumferential shape of the cooling tank when viewed from the longitudinal direction of the cooling tank, forming a refrigerant flow that rotates along the circumferential direction of the cooling tank. Therefore, the conversion member changes the refrigerant flow direction and converts the refrigerant flow pattern so that a refrigerant flow that rotates along the circumferential direction of the cooling tank is formed. The refrigerant whose flow pattern has been converted by the conversion member rotates along the circumferential direction of the cooling tank and flows from the bottom side to the top side of the inlet pipe, and is introduced into the cooling tank from the inlet pipe. The refrigerant introduced into the cooling tank flows through the tank while rotating around the periphery of the cooling tank and forming a swirling flow along the longitudinal direction of the cooling tank. This swirling flow of the refrigerant allows the workpiece placed in the cooling tank to be uniformly cooled from all around the workpiece.

[0012] Therefore, according to the above configuration, a conversion member is provided in the inlet pipe connected to the cooling tank, extending along the longitudinal direction of the cooling tank and having a curved or bent surface that conforms to the inner circumferential shape of the cooling tank when viewed from the longitudinal direction of the cooling tank, thereby forming a swirling flow that uniformly cools the workpiece in the cooling tank. Therefore, according to the above configuration, when introducing the refrigerant supplied from the inlet pipe into the cooling tank and further forming the swirling flow of the refrigerant flowing within the cooling tank, it is not necessary to provide a structure that extends spirally along the inner circumferential direction of the cooling tank. Therefore, since it is not necessary to provide a structure that extends spirally along the longitudinal direction of the cooling tank to form a swirling flow, the cooling tank can be shortened, and the overall configuration of the heat treatment device can be shortened.

[0013] Furthermore, according to the above configuration, the conversion member is formed as a surface component that can be machined in two dimensions and has a curved or bent surface that follows the inner circumferential shape of the cooling tank when viewed from the longitudinal direction of the cooling tank, and extends between the bottom and top sides of the inlet pipe, so that the component for forming a swirling flow in the cooling tank can be manufactured with a simple structure.

[0014] Furthermore, since it is formed as a surface component that can be machined in two dimensions, the components for forming the swirling flow can be easily fixed inside the device.

[0015] Therefore, according to the above configuration, it is possible to provide a heat treatment device that can shorten the overall configuration of the heat treatment device capable of forming a swirling flow for cooling the workpiece, that can manufacture the parts for forming the swirling flow in the cooling tank with a simple structure, and that can easily fix the parts for forming the swirling flow within the device.

[0016] (2) The surfaces may be arranged in a spiral shape when viewed from the longitudinal direction of the cooling tank.

[0017] With this configuration, the refrigerant that has flowed through the inlet pipe and reached the conversion member flows in a rotating manner along the spirally arranged surface when viewed from the longitudinal direction of the cooling tank, and therefore, a rotating refrigerant flow can be formed by the surface of the conversion member.

[0018] (3) A plurality of the surfaces may be provided, and the surfaces may be arranged in a spiral shape when viewed from the longitudinal direction of the cooling tank.

[0019] With this configuration, the refrigerant that has flowed through the inlet pipe and reached the conversion member flows in a rotating manner along the multiple surfaces that are arranged in a spiral when viewed from the longitudinal direction of the cooling tank, thereby forming a rotating refrigerant flow by the multiple surfaces of the conversion member.

[0020] (4) The conversion member may have a first surface configured as the surface and arranged to be curved or bent so as to be concave toward the end side of the inlet pipe, and a second surface configured as the surface and arranged at a position opposite to the first surface via the central axis direction of the cooling tank, and arranged to be curved or bent so as to be concave toward the opposite side of the first surface.

[0021] With this configuration, the refrigerant that has flowed through the inlet pipe and reached the conversion member flows so as to rotate along the first surface of the conversion member, and then flows so as to rotate along the second surface, thereby forming a rotating flow of the refrigerant by the first surface and the second surface.

[0022] (5) The conversion member may further include a third surface configured as the surface, positioned between the first surface and the second surface in a position facing the second surface, and curved or bent so as to be concave toward the side opposite the second surface.

[0023] With this configuration, the refrigerant that has flowed through the inlet pipe and reached the conversion member flows so as to rotate along the first surface of the conversion member, then flows so as to rotate along the second surface, and then further flows so as to rotate along the third surface, thereby forming a more stable rotating flow of the refrigerant by the first surface, second surface, and third surface.

[0024] (6) The conversion member may include a first member that extends along the longitudinal direction of the cooling tank between the bottom side and the top side of the inlet pipe and has the first surface, and a second member that extends along the longitudinal direction of the cooling tank between the bottom side and the top side of the inlet pipe and has the second surface.

[0025] If the conversion member is made as a single piece, and if it is larger than the opening between the inlet pipe and the cooling tank, it would be difficult to insert and assemble the conversion member through the opening between the inlet pipe and the cooling tank. However, with this configuration, by dividing the conversion member into a first member and a second member, it is possible to insert and assemble the conversion member through the opening between the inlet pipe and the cooling tank. [Effects of the Invention]

[0026] According to the present invention, it is possible to provide a heat treatment device that can shorten the overall structure of the heat treatment device capable of forming a swirling flow for cooling the workpiece, that can manufacture components for forming a swirling flow in a cooling tank with a simple structure, and that can easily fix the components for forming a swirling flow within the device. [Brief explanation of the drawings]

[0027] [Figure 1] 1 is a diagram schematically illustrating a heat treatment apparatus according to an embodiment of the present invention. [Figure 2] FIG. 2 is a perspective view showing a cooling bath and an introduction pipe of the heat treatment apparatus. [Figure 3] FIG. 2 is a cross-sectional view of the cooling tank and the introduction pipe as viewed from the front side. [Figure 4] FIG. 2 is a plan view of the cooling tank and the inlet pipe, showing the cooling tank in cross section. [Figure 5] 3 is an enlarged perspective view showing a part of the cooling tank and the introduction pipe shown in FIG. 2. FIG. [Figure 6] 5 is an enlarged plan view showing a part of the cooling tank and the introduction pipe shown in FIG. 4. [Figure 7] FIG. 10 is a perspective view showing a conversion member in the introduction pipe. [Figure 8] FIG. 10 is a plan view showing a conversion member in the introduction pipe. [Figure 9] FIG. 10 is a diagram showing the results of analyzing the flow lines of the refrigerant in a comparative example. [Figure 10] FIG. 10 is a diagram showing the results of analyzing the flow lines of the refrigerant in the example. [Figure 11]FIG. 10 is a diagram showing the results of analyzing the flow velocity distribution of the refrigerant in the cooling tank in the comparative example. [Figure 12] FIG. 10 is a diagram showing the results of analyzing the flow velocity distribution of the refrigerant in the cooling tank in the example. [Figure 13] FIG. 13(A) is a perspective view showing a conversion member according to a first modified example, and FIG. 13(B) is a plan view showing the conversion member of the first modified example. [Figure 14] 14(A) and 14(B) are perspective views illustrating an assembly form of an inlet pipe and a cooling tank equipped with a conversion member of a first modified example. [Figure 15] Fig. 15(A) is a plan view showing a conversion member according to a second modified example, Fig. 15(B) is a plan view showing a conversion member according to a third modified example, and Fig. 15(C) is a plan view showing a conversion member according to a fourth modified example. [Figure 16] FIG. 10 is a plan view showing a conversion member according to a fifth modified example. [Figure 17] FIG. 13 is a perspective view showing a conversion member according to a sixth modified example. DETAILED DESCRIPTION OF THE INVENTION

[0028] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0029] [Overall configuration of heat treatment equipment] Fig. 1 is a diagram schematically illustrating a heat treatment apparatus according to one embodiment of the present invention. Referring to Fig. 1, heat treatment apparatus 1 is configured as an apparatus for performing heat treatment on workpiece 10. More specifically, heat treatment apparatus 1 is configured as an apparatus for heating workpiece 10 in heating tank 12, transporting heated workpiece 10 to cooling tank 13, and supplying a refrigerant to workpiece 10 in cooling tank 13 to perform heat treatment.

[0030] Examples of heat treatments performed in the heating tank 12 of the heat treatment device 1 include annealing, tempering, and carburizing. Examples of heat treatments performed as cooling treatments in the cooling tank 13 of the heat treatment device 1 include quenching. In this embodiment, quenching will be described as an example. In this embodiment, a polymer aqueous solution is used as the refrigerant used to perform heat treatment on the workpiece 10 in the cooling tank 13. The refrigerant used for heat treatment in the cooling tank 13 is not limited to a polymer aqueous solution, and any fluid capable of cooling the workpiece 10 may be used. For example, cooling water or quenching oil may be used as the refrigerant.

[0031] In this embodiment, the workpiece 10 to be heat treated in the cooling bath 13 of the heat treatment apparatus 1 is a metal part such as steel, for example, a cylindrically extending hollow shaft-shaped part. Examples of the workpiece 10 as a cylindrically extending hollow shaft-shaped part include a cylindrical steel pipe, a hollow shaft-shaped part whose cross-sectional area decreases in a tapered manner along the longitudinal direction, a hollow shaft-shaped part whose cross-sectional area decreases stepwise along the longitudinal direction, and a cylindrical part whose cross-sectional shape is other than circular, such as a polygonal shape.

[0032] Furthermore, the workpieces to be heat-treated in the heat treatment device 1 are not limited to hollow shaft-shaped parts, but may also include solid shaft-shaped parts with a circular cross section, and short parts such as gears or bearings. When heat treatment is performed on short gears or bearings, the gears or bearings may be stacked in the axial direction. Furthermore, examples of the material of the workpiece 10 include materials that require quenching in practice. Examples of such materials include SCM (chromium-molybdenum steel), SCr (chromium steel), SNCM (nickel-chromium-molybdenum steel), and SUJ (high-carbon chromium bearing steel).

[0033] As will be described later, the heat treatment device 1 is configured such that when the workpiece 10, after being heated in the heating tank 12, is cooled in the cooling tank 13 for heat treatment, the flow of the refrigerant in the cooling tank 13 is made into a swirling flow, and the swirling flow formed around the workpiece 10 uniformly cools the workpiece 10.

[0034] The heat treatment apparatus 1 is configured to include a transfer device 11, a heating tank 12, a cooling tank 13, an introduction pipe 14, a refrigerant tank 15, a pump 16, a drain passage 17, and the like.

[0035] The transport device 11 is configured as a device that supports the workpiece 10 in a suspended state and transports the supported workpiece 10 between the heating tank 12 and the cooling tank 13. The transport device 11 includes, for example, a main body 11a installed above the heating tank 12, the cooling tank 13, the drain passage 17, and the refrigerant tank 15, a horizontal movement part 11b supported by the main body 11a, and a vertical movement part 11c supported by the horizontal movement part 11b.

[0036] The horizontal moving unit 11b is driven by the main body 11a and configured to move in the horizontal direction. In FIG. 1, the movement direction of the horizontal moving unit 11b is indicated by a double-headed arrow A1. The vertical moving unit 11c is configured to support the workpiece 10 in a suspended state and to move in the vertical direction by being driven by the horizontal moving unit 11b. In FIG. 1, the movement direction of the vertical moving unit 11c is indicated by a double-headed arrow A2. The vertical moving unit 11c also has a support shaft 11d that supports the workpiece 10 in a suspended state and a receiving portion 11e that is provided at the lower end of the support shaft 11d and receives the workpiece 10. The support shaft 11d is supported by the horizontal moving unit 11b in a state where it extends in the vertical direction and is movable in the vertical direction. Furthermore, the support shaft 11d is configured to suspend and support the workpiece 10 in a state where it vertically penetrates the workpiece 10, which is a hollow shaft-shaped component. The receiving portion 11e is provided as a disk-shaped member provided at the lower end of the support shaft 11d, and is configured to receive from below the lower end of the workpiece 10 through which the support shaft 11d passes.

[0037] The transport device 11 supports the workpiece 10 by suspending it with the vertical movement unit 11c, and drives the vertical movement unit 11c downward by the horizontal movement unit 11b, thereby inserting and placing the workpiece 10 into the heating tank 12 from above. The workpiece 10 placed in the heating tank 12 is subjected to a heat treatment within the heating tank 12. After the heat treatment in the heating tank 12, the transport device 11 drives the vertical movement unit 11c upward by the horizontal movement unit 11b, thereby lifting the workpiece 10 from the heating tank 12. The transport device 11 then drives the horizontal movement unit 11b by the main body unit 11a, and moves the horizontal movement unit 11b horizontally until the vertical movement unit 11c supporting the workpiece 10 is positioned above the cooling tank 13. Next, the transport device 11 drives the vertical movement unit 11c downward by the horizontal movement unit 11b, thereby inserting and placing the workpiece 10 into the cooling tank 13 from above. Cooling tank 13 is filled with a refrigerant circulating between cooling tank 13 and refrigerant tank 15 via inlet pipe 14 and drain passage 17 up to a liquid level C, which corresponds to a height position where workpiece 10 can be entirely immersed. In FIG. 1 , the liquid level C of the refrigerant in cooling tank 13 is indicated by a dashed line. When workpiece 10 is placed in cooling tank 13 filled with refrigerant, it is immersed in the refrigerant in cooling tank 13, and heat treatment of workpiece 10 is performed. After heat treatment in cooling tank 13, conveying device 11 drives vertical movement unit 11c by horizontal movement unit 11b to move upward, and lifts workpiece 10 from cooling tank 13. This completes the heat treatment of workpiece 10.

[0038] The heating tank 12 has a heating chamber 12a into which the workpiece 10 is carried by the transport mechanism 11, and is configured to perform a heat treatment on the workpiece 10 placed inside the heating chamber 12a. The heating tank 12 has, for example, a heating coil (not shown) installed inside the heating chamber 12a, and is configured to heat the workpiece 10 placed inside the heating chamber 12a by induction heating.

[0039] The cooling tank 13 is configured as a cylindrical tank in which the workpiece 10 is placed, and is provided so as to extend in the vertical direction. The cooling tank 13 is configured so that the refrigerant circulating between the cooling tank 13 and the refrigerant tank 15 via the inlet pipe 14 and the drain passage 17 is filled up to a liquid level C corresponding to a height position where the entire workpiece 10 can be immersed. The inlet pipe 14 is configured as a tubular structure that introduces the refrigerant used to heat treat the workpiece 10 into the cooling tank 13. The inlet pipe 14 is provided so as to extend in the horizontal direction and is connected to the end portion on the lower end side of the cooling tank 13. Therefore, the cooling tank 13 and the inlet pipe 14 are connected such that the longitudinal direction of the cooling tank 13 and the longitudinal direction of the inlet pipe 14 are different. The specific configurations of the cooling tank 13 and the inlet pipe 14 will be described in detail later.

[0040] The refrigerant tank 15 is provided as a tank for temporarily storing the refrigerant, which is supplied to the cooling tank 13 while circulating between the refrigerant tank 15 and the cooling tank 13, on the refrigerant circulation path. The refrigerant tank 15 is connected to the cooling tank 15 via a drain passage 17. The refrigerant tank 15 has a heat exchanger (not shown) and is configured to cool the refrigerant that returns from the cooling tank 13 via the drain passage 17. The drain passage 17 is provided as a refrigerant flow path that returns the refrigerant that has cooled the workpiece 10 in the cooling tank 13 to the refrigerant tank 15. The drain passage 17 is connected to the upper end side of the cooling tank 13 and also to the upper end of the refrigerant tank 15. The refrigerant that exceeds the liquid level C in the cooling tank 13 overflows from the cooling tank 13, flows out into the drain passage 17, and returns to the refrigerant tank 15 from the drain passage 17.

[0041] Refrigerant tank 15 is also connected to introduction pipe 14 via refrigerant supply passage 18. Refrigerant supply passage 18 is provided as a refrigerant flow path that supplies refrigerant cooled in refrigerant tank 15 to introduction pipe 14. Refrigerant supply passage 18 is connected to the lower end side of refrigerant tank 15, and is connected to introduction pipe 14 at an end of introduction pipe 14 opposite to the end connected to cooling tank 13. Refrigerant supply passage 18 is also provided with pump 16. Pump 16 is configured to suck refrigerant stored in refrigerant tank 15 via refrigerant supply passage 18 and supply it to introduction pipe 14.

[0042] [Cooling tank] FIG. 2 is a perspective view showing the cooling tank 13 and the introduction pipe 14 of the heat treatment apparatus 1. FIG. 3 is a cross-sectional view of the cooling tank 13 and the introduction pipe 14 as viewed from the front side. FIG. 4 is a plan view of the cooling tank 13 and the introduction pipe 14, showing the cooling tank 13 in cross section. FIG. 5 is a perspective view showing an enlarged portion of the cooling tank 13 and the introduction pipe 14 shown in FIG. 2. FIG. 6 is a plan view showing an enlarged portion of the cooling tank 13 and the introduction pipe 14 shown in FIG. 4. In FIG. 3, the workpiece 10 placed in the cooling tank 13 is shown by a two-dot chain line.

[0043] 1 to 6, the cooling tank 13 is provided as a cylindrical tank in which the workpiece 10 is placed, and in this embodiment, is configured as a cylindrical tank. The cooling tank 13 is configured to extend cylindrically along the vertical direction, and in this embodiment, the longitudinal direction of the cylindrically extending cooling tank 13 is parallel to the vertical direction. The longitudinal direction of the cooling tank 13 is indicated by a double-ended arrow L1 in FIGS. 2 and 3. The cooling tank 13 also has a cylindrical peripheral wall portion 13a and a bottom wall portion 13b provided at the lower end of the peripheral wall portion 13a.

[0044] The cooling tank 13 has an upper end opening 13c with a circular cross section at the upper end of the peripheral wall 13a. That is, the peripheral wall 13a has an open upper end. The workpiece 10 supported by the vertically moving part 11c of the transport device 11 is inserted into the cooling tank 13 through the upper end opening 13c and placed in the cooling tank 13. A drain passage 17 is connected to the side of the upper end of the peripheral wall 13a. The drain passage 17 is connected to the upper end side of the peripheral wall 13a, and the refrigerant introduced into the cooling tank 13 from the inlet pipe 14 rises along the peripheral wall 13a to a height position where it connects to the drain passage 17, and then flows out into the drain passage 17.

[0045] The bottom wall 13b of the cooling tank 13 is connected to the end of the introduction pipe 14. The bottom wall 13b is provided with a lower end opening 13d that penetrates the bottom wall 13b, opens toward the lower end of the cooling tank 13, and communicates with the end of the introduction pipe 14. The lower end opening 13d is formed, for example, to have a rectangular shape. The refrigerant introduced from the introduction pipe 14 into the cooling tank 13 passes through the lower end opening 13d and is introduced into the cooling tank 13.

[0046] [Introduction pipe] 1 to 6, the introduction pipe 14 is provided as a tubular structure for introducing a refrigerant into the cooling tank 13, and includes a pipe main body 20 and a conversion member 21 arranged within the pipe main body 20.

[0047] The pipe body 20 is a rectangular tubular member with a rectangular cross section, and is configured to extend horizontally in a rectangular tubular shape. The longitudinal direction of the pipe body 20 extending in a rectangular tubular shape corresponds to the longitudinal direction of the inlet pipe 14. The longitudinal direction of the inlet pipe 14 and the pipe body 20 is indicated by double-ended arrows L2 in Figures 2 to 4. The pipe body 20 has an elongated box-like shape with a rectangular cross section and includes a top wall 20a, a bottom wall 20b, a pair of side walls 20c and 20d, and a pair of end walls 20e and 20f. The top wall 20a serves as a wall portion on the top side of the inlet pipe 14, and the bottom wall 20b serves as a wall portion on the bottom side of the inlet pipe 14. The pair of side walls 20c and 20d have a height along the vertical direction and extend parallel to the longitudinal direction of the inlet pipe 14. The pair of side walls 20c and 20d constitute wall portions on both sides of the width direction of the introduction pipe 14, which is a direction horizontal and perpendicular to the longitudinal direction of the introduction pipe 14. The width direction of the introduction pipe 14 is indicated by a double-ended arrow W in Figures 4 and 6. The pair of end walls 20e and 20f are provided as wall portions that close the end faces of both ends of the introduction pipe 14 in the longitudinal direction from the outside.

[0048] Furthermore, the tube body 20 is connected to the lower end of the cooling tank 13 at the upper surface side of one longitudinal end of the tube body 20, i.e., at one longitudinal end of the upper wall 20a. A cooling tank-side opening 22a is formed at the portion of the upper surface of one longitudinal end of the tube body 20 that connects to the cooling tank 13 (see FIG. 3). The cooling tank-side opening 22a is located in correspondence with a lower end opening 13d provided in the bottom wall portion 13b of the cooling tank 13 that is connected to the tube body 20. In this embodiment, the cooling tank-side opening 22a of the tube body 20 and the lower end opening 13d of the cooling tank 13 are formed as openings with the same opening area and shape, and are arranged so as to overlap in the vertical direction. However, the cooling tank side opening 22a of the pipe body 20 and the lower end opening 13d of the cooling tank 13 do not have to have the same shape; for example, the cooling tank side opening 22a of the pipe body 20 may be formed as an opening with a larger opening area than the lower end opening 13d of the cooling tank 13.

[0049] The pipe body 20 is connected to the lower end of the refrigerant supply passage 18 at the upper surface side of the other longitudinal end, i.e., at the other longitudinal end of the upper wall 20a. A supply passage-side opening 22b is formed at the portion of the upper surface of the other longitudinal end of the pipe body 20 that connects to the refrigerant supply passage 18. The lower end of the refrigerant supply passage 18 is open, and the lower end of the refrigerant supply passage 18 is connected to the supply passage-side opening 22b. The refrigerant supplied from the refrigerant supply passage 18 flows from the lower end of the refrigerant supply passage 18 into the supply passage-side opening 22b of the pipe body 20 and flows along the longitudinal direction of the pipe body 20. The refrigerant that has flowed through the pipe body 20 then flows from the cooling tank-side opening 20a of the pipe body 20 into the lower end opening 13d of the cooling tank 13 and flows through the cooling tank 13.

[0050] As described above, in this embodiment, the longitudinal direction of the pipe body 20 of the introduction pipe 14, which extends in a rectangular cylindrical shape, is parallel to the horizontal direction. The longitudinal direction of the cooling tank 13 connected to the introduction pipe 14 is parallel to the up-down direction. Therefore, the cooling tank 13 and the introduction pipe 14 are connected such that the longitudinal directions of the cooling tank 13 and the introduction pipe 14 are in different directions. In this embodiment, the cooling tank 13 and the introduction pipe 14 are connected in a direction in which the longitudinal directions of the cooling tank 13 and the introduction pipe 14 intersect at a right angle. The embodiment is not limited to a configuration in which the longitudinal directions of the cooling tank 13 and the introduction pipe 14 intersect at a right angle. Alternatively, the cooling tank 13 and the introduction pipe 14 may be connected in a direction in which the longitudinal directions of the cooling tank 13 and the introduction pipe 14 intersect at an angle other than a right angle.

[0051] Fig. 7 is a perspective view showing conversion member 21 in lead-in pipe 14. Fig. 8 is a plan view showing conversion member 21 in lead-in pipe 14. With reference to Figs. 1 to 8, conversion member 21 is disposed inside pipe main body 20 in lead-in pipe 14, and is disposed at one end of lead-in pipe 14 in the longitudinal direction. Conversion member 21 is provided as a member that changes the flow of refrigerant at the end of lead-in pipe 14 that is connected to cooling tank 13, and that forms a refrigerant flow that rotates in the circumferential direction of cooling tank 13. The conversion member 21 will be described in more detail below.

[0052] 2 to 8, the conversion member 21 is configured to include a first member 23 and a second member 24. The first member 23 and the second member 24 are both disposed inside the tube body 20, at the end of the tube body 20 that is connected to the cooling tank 13. At the end of the tube body 20 that is connected to the cooling tank 13, the first member 23 is disposed adjacent to the end wall 20e, and the second member 24 is disposed on the opposite side of the first member 23 to the end wall 20e.

[0053] The first member 23 and the second member 24 are both provided as plate-like members having curved portions. The first member 23 and the second member 24 are both provided to extend along the longitudinal direction of the cooling tank 13, between the bottom and top sides of the pipe body 20 of the introduction pipe 14. More specifically, the first member 23 is provided inside the pipe body 20, on the end wall 20e side, to extend between the bottom wall 20b and the top wall 20a in a vertical direction parallel to the longitudinal direction of the cooling tank 13. The second member 24 is provided inside the pipe body 20, on the opposite side of the end wall 20e from the first member 23, to extend between the bottom wall 20b and the top wall 20a in a vertical direction parallel to the longitudinal direction of the cooling tank 13. With the first member 23 and the second member 24 arranged as described above, the conversion member 21 is arranged to extend along the longitudinal direction of the cooling tank 13 between the bottom side and the top side of the inlet pipe 14.

[0054] The height of the first member 23 is set to be equal to the height of the pipe main body 20. More specifically, the height of the first member 23, i.e., the vertical length of the first member 23, is set to be equal to the height of the pipe main body 20, i.e., the vertical distance between the bottom wall 20b and the top wall 20a. Note that, for example, the lower end of the first member 23 is fixed to the bottom wall 20b and the upper end is abutting the top wall 20a, but this is not necessarily the case. The upper end of the first member 23 may be fixed to the top wall 20a and the lower end 20b may abut the bottom wall 20b. Furthermore, when the lower end of the first member 23 is fixed to the bottom wall 20b, the upper end may face the top wall 20a via a gap to the extent that the flow of refrigerant along the surface of the first member 23 is hardly affected. Furthermore, when the upper end of the first member 23 is fixed to the upper wall 20a, the lower end may face the bottom wall 20b via a gap to the extent that there is almost no effect on the flow of refrigerant along the surface of the first member 23.

[0055] The width of the first member 23 is set to be equal to the width of the pipe main body 20. More specifically, the width of the first member 23, i.e., the length of the first member 23 in the width direction of the inlet pipe 14, is set to be equal to the width of the pipe main body 20, i.e., the distance between the sidewall 20c and the sidewall 20d in the width direction of the inlet pipe 14. Note that, for example, one end of the first member 23 in the width direction abuts the sidewall 20c and the other end of the first member 23 in the width direction abuts the sidewall 20d, but this is not necessarily the case. One end of the first member 23 in the width direction may face the sidewall 20c via a gap to the extent that the flow of the refrigerant along the surface of the first member 23 is hardly affected. The other end of the first member 23 in the width direction may face the sidewall 20d via a gap to the extent that the flow of the refrigerant along the surface of the first member 23 is hardly affected.

[0056] The height of the second member 24 is set to be equal to the height of the pipe main body 20. More specifically, the height of the second member 24, i.e., the vertical length of the second member 24, is set to be equal to the height of the pipe main body 20, i.e., the vertical distance between the bottom wall 20b and the top wall 20a. Note that, for example, the lower end of the second member 24 is fixed to the bottom wall 20b and the upper end is abutting the top wall 20a, but this is not necessarily the case. The upper end of the second member 24 may be fixed to the top wall 20a and the lower end 20b abutting the bottom wall 20b. Furthermore, when the lower end of the second member 24 is fixed to the bottom wall 20b, the upper end may face the top wall 20a via a gap to the extent that the flow of refrigerant along the surface of the second member 24 is hardly affected. Furthermore, when the upper end of the second member 24 is fixed to the upper wall 20a, the lower end may face the bottom wall 20b via a gap to the extent that there is almost no effect on the flow of refrigerant along the surface of the second member 24.

[0057] The width of the second member 24 is set smaller than the width of the pipe main body 20. More specifically, the width of the second member 24, i.e., the length of the second member 24 in the width direction of the inlet pipe 14, is set smaller than the width of the pipe main body 20, i.e., the distance between the side wall 20c and the side wall 20d in the width direction of the inlet pipe 14. One end of the second member 24 in the width direction abuts the side wall 20d, and the other end of the second member 24 in the width direction is positioned away from the side wall 20c so as to ensure a flow path for the refrigerant. The refrigerant that flows through the inlet pipe 14 and reaches the region where the second member 24 is located passes between the second member 24 and the side wall 20c.

[0058] Furthermore, when viewed from the longitudinal direction of the cooling tank 13 (i.e., when viewed from the top to bottom), the first member 23 has a first curved portion 25 that extends in an arc shape toward the end wall 20e, which is the end side of the introduction pipe 14. The first curved portion 25 of the first member 23 that extends in an arc shape is arranged to extend along the inner circumferential shape of the cooling tank 13 when viewed from the longitudinal direction of the cooling tank 13. Note that the inner circumferential shape of the cooling tank 13 when viewed from the longitudinal direction of the cooling tank 13, i.e., the inner circumferential shape of the peripheral wall portion 13a, is circular. The curved portion 25 that extends in an arc shape is arranged to extend along the arc portion of the inner circumferential shape of the circular cooling tank 13.

[0059] Since the first curved portion 25 is configured as described above, the curved inner surface 25a of the first curved portion 25, i.e., the surface 25a of the first curved portion 25 facing the side opposite to the end wall 20e side, is configured as a curved surface 25a that follows the inner circumferential shape of the cooling tank 13 when viewed from the longitudinal direction of the cooling tank 13. The surface 25a of the first curved portion 25 is arranged so as to be curved in an arc concave toward the end wall 20a side, which is the end side of the introduction pipe 14. The surface 25a of the first curved portion 25 constitutes the first surface of this embodiment that is curved in a concave manner toward the end side of the introduction pipe 14.

[0060] The second member 24 also has a second curved portion 26, a third curved portion 27, and a connecting portion 28 that connects the second curved portion 26 and the third curved portion 27 together.

[0061] The second curved portion 26 of the second member 24 is disposed at a position opposite the first curved portion 25 of the first member 23 across the central axis direction of the cooling tank 13. The central axis direction of the cooling tank 13 is indicated by point P in FIG. 6. The width of the second curved portion 26 opposite the first curved portion 25 is set smaller than the width of the first curved portion 25. More specifically, the width of the second curved portion 26, i.e., the length of the second curved portion 26 in the width direction of the introduction pipe 14, is set smaller than the width of the first curved portion 25, i.e., the length of the first curved portion 25 in the width direction of the introduction pipe 14. Furthermore, when viewed from the longitudinal direction of the cooling tank 13, the second curved portion 26 curves and extends in an arc shape toward the side opposite the end wall 20e, which is the end side of the introduction pipe 14. Therefore, second curved portion 26 extends in an arc-like curve toward the side opposite to the side where first curved portion 25 extends in an arc-like curve. Second curved portion 27, which extends in an arc-like curve, is arranged to extend along the arc portion of the inner circumferential shape of cooling tank 13, which is circular, when viewed from the longitudinal direction of cooling tank 13.

[0062] Because the second curved portion 26 is configured as described above, the curved inner surface 26a of the second curved portion 26, i.e., the surface 26a of the second curved portion 26 facing the end wall 20e, is configured as a curved surface 26a that follows the inner circumferential shape of the cooling tank 13 when viewed from the longitudinal direction of the cooling tank 13. The surface 26a of the second curved portion 26 is disposed at a position opposite to the surface 25a of the first curved portion 25 across the central axis direction of the cooling tank 13, and is curved so as to be concave toward the side opposite to the surface 25a of the first curved portion 25. The surface 26a of the second curved portion 26 is disposed at a position opposite to the surface 25a (first surface 25a) of the first curved portion 25 across the central axis direction of the cooling tank 13, and constitutes the second surface of this embodiment that is curved so as to be concave toward the side opposite to the surface 25a (first surface 25a).

[0063] The third curved portion 27 of the second member 24 is disposed between the first curved portion 25 of the first member 23 and the second curved portion 26 of the second member 24 at a position facing the second curved portion 26. The width of the third curved portion 27 facing the second curved portion 26 is set smaller than the width of the second curved portion 26. More specifically, the width of the third curved portion 27, i.e., the length of the third curved portion 27 in the width direction of the introduction pipe 14, is set smaller than the width of the second curved portion 26, i.e., the length of the second curved portion 26 in the width direction of the introduction pipe 14. Furthermore, when viewed from the longitudinal direction of the cooling tank 13, the third curved portion 27 curves and extends in an arc-like manner toward the end wall 20e, which is the end side of the introduction pipe 14. Therefore, the third curved portion 27 curves and extends in an arc-like manner toward the same side as the first curved portion 25 curves and extends in an arc-like manner. Furthermore, when viewed from the longitudinal direction of the cooling tank 13, the third curved portion 27 is disposed between the central axis direction of the cooling tank 13 and the first curved portion 25. Furthermore, when viewed from the longitudinal direction of the cooling tank 13, the third curved portion 27 is disposed so as to extend in an arc shape on a circle concentric with the inner circumferential shape of the circular cooling tank 13, the circle being centered on the central axis direction of the cooling tank 13. Therefore, when viewed from the longitudinal direction of the cooling tank 13, the third curved portion 27 extending in an arc shape is disposed so as to extend concentrically along the inner circumferential shape of the cooling tank 13.

[0064] Because the third curved portion 27 is configured as described above, the curved inner surface 27a of the third curved portion 27, i.e., the surface 27a of the third curved portion 27 facing the second curved portion 26, is configured as a curved surface 27a that is concentric with the inner circumferential shape of the cooling tank 13 when viewed from the longitudinal direction of the cooling tank 13. The surface 27a of the third curved portion 27 is disposed at a position facing the surface 26a of the second curved portion 26 between the surface 25a of the first curved portion 25 and the surface 26a of the second curved portion 26, and is disposed so as to be curved so as to be recessed toward the side opposite the surface 26a of the second curved portion 26. The surface 27a of the third curved portion 27 is positioned opposite the surface 26a (second surface 26a) between the surface 25a (first surface 25a) of the first curved portion 25 and the surface 26a (second surface 26a) of the second curved portion 26, and constitutes the third surface of this embodiment, which is curved so as to be concave toward the side opposite the surface 26a (second surface 26a).

[0065] The connecting portion 28 is provided in the second member 24 as a portion that connects the second curved portion 26 and the third curved portion 27. The connecting portion 28 extends continuously from the second curved portion 26 and is continuously connected to the third curved portion 27. The connecting portion 28 is provided to extend from the end of the second curved portion 26 to a position approximately midway between the second curved portion 26 and the first curved portion 25. In the present embodiment, the connecting portion 28 is provided to extend linearly along the longitudinal direction of the introduction pipe 14 when viewed from the longitudinal direction of the cooling tank 13.

[0066] As described above, the first member 23 has a curved surface 25a that follows the inner circumferential shape of the cooling tank 13 when viewed from the longitudinal direction of the cooling tank 13. The second member 24 has curved surfaces (26a, 27a) that follow the inner circumferential shape of the cooling tank 13 when viewed from the longitudinal direction of the cooling tank 13. Therefore, the conversion member 21 including the first member 23 and the second member 24 has curved surfaces (25a, 26a, 27a) that follow the inner circumferential shape of the cooling tank 13 when viewed from the longitudinal direction of the cooling tank 13. In this embodiment, the curved surfaces (25a, 26a, 27a) that follow the inner circumferential shape of the cooling tank 13 when viewed from the longitudinal direction of the cooling tank 13 are arranged along concentric circles whose centers are aligned with the circumference of the inner circumferential shape of the cooling tank 13 when viewed from the longitudinal direction of the cooling tank 13.

[0067] Furthermore, the surfaces (25a, 26a, 27a) of the conversion member 21 are arranged in a spiral shape (i.e., a vortex shape) when viewed from the longitudinal direction of the cooling tank 13. The conversion member 21 is provided with a plurality of surfaces (25a, 26a, 27a), and the surfaces (25a, 26a, 27a) are arranged in a spiral shape when viewed from the longitudinal direction of the cooling tank 13. The surfaces (25a, 26a, 27a) are arranged in the order of surface 25a, surface 26a, and surface 27a in a spiral shape that decreases in diameter from the outer periphery to the inner periphery when viewed from the longitudinal direction of the cooling tank 13.

[0068] [Flow pattern of refrigerant introduced from the introduction pipe into the cooling tank] Next, the flow of the refrigerant introduced from the inlet pipe 14 into the cooling tank 13 will be described with reference to Figures 4 to 6. In Figures 4 to 6, the flow of the refrigerant flowing through the inlet pipe 14 and introduced into the cooling tank 13 is indicated by dashed arrows.

[0069] 4, the refrigerant supplied from refrigerant supply passage 18 to lead-in pipe 14 flows into lead-in pipe 14 from supply passage-side opening 22b of lead-in pipe 14. The refrigerant that has flowed in from supply passage-side opening 22b flows inside lead-in pipe 14 along the longitudinal direction of lead-in pipe 14 and reaches conversion member 21 that is arranged at the end of lead-in pipe 14 on the side to which cooling tank 13 is connected.

[0070] 5 and 6, the refrigerant that has reached the conversion member 21 flows through the flow path between the connecting portion 28 of the second member 24 and the side wall 20c of the pipe main body 20, and reaches the first member 23. The refrigerant that has reached the first member 23 flows along the curved surface 25a of the first curved portion 25. The refrigerant that has flowed along the surface 25a of the first curved portion 25 then flows toward the second curved portion 26 of the second member 24. The refrigerant that has reached the second curved portion 26 flows along the curved surface 26a of the second curved portion 26, and further flows toward the third curved portion 27. The refrigerant that has reached the third curved portion 27 then flows along the curved surface 27a of the third curved portion 27.

[0071] The refrigerant that flows along the longitudinal direction of the inlet pipe 14 and reaches the conversion member 21 flows along the first curved portion 25 of the first member 23 and the second curved portion 26 and third curved portion 27 of the second member 24, as described above. The first member 23 and the second member 24 extend along the longitudinal direction of the cooling tank 13 between the bottom surface side and the top surface side of the inlet pipe 14. Therefore, the refrigerant that flows along the longitudinal direction of the inlet pipe 14 and reaches the conversion member 21 flows along the first member 23 and the second member 24, thereby changing its flow direction so that it flows along the longitudinal direction of the cooling tank 13. The refrigerant that flows through the inlet pipe 14 and reaches the conversion member 21 flows along the surface 25a of the first curved portion 25, the surface 26a of the second curved portion 26, and the surface 27a of the third curved portion 27, as described above. The surface 25a of the first curved portion 25, the surface 26a of the second curved portion 26, and the surface 27a of the third curved portion 27 are curved surfaces that follow the inner circumferential shape of the cooling tank 13 when viewed from the longitudinal direction of the cooling tank 13. Therefore, the refrigerant flows along the surface 25a of the first curved portion 25, the surface 26a of the second curved portion 26, and the surface 27a of the third curved portion 27, thereby forming a refrigerant flow that rotates along the circumferential direction of the cooling tank 13. Furthermore, the curved surfaces (25a, 26a, 27a) that follow the inner circumferential shape of the cooling tank 13 when viewed from the longitudinal direction of the cooling tank 13 are arranged along concentric circles whose centers are aligned with the circumference of the inner circumferential shape of the cooling tank 13 when viewed from the longitudinal direction of the cooling tank 13. Therefore, the rotating flow of the refrigerant formed by flowing along the curved surfaces (25a, 26a, 27a) becomes a flow that rotates around the central axis direction of the cooling tank 13.

[0072] As described above, the refrigerant that flows along the longitudinal direction of lead-in pipe 14 and reaches conversion member 21 has its flow direction changed by conversion member 21 from a flow along the longitudinal direction of lead-in pipe 14 to a flow along the longitudinal direction of cooling tank 13. Furthermore, the refrigerant flows along curved surfaces (25a, 26a, 27a) that conform to the inner circumferential shape of cooling tank 13, forming a refrigerant flow that rotates along the circumferential direction of cooling tank 13. Therefore, the flow direction of the refrigerant is changed by conversion member 21, and the flow pattern is converted so that a refrigerant flow that rotates along the circumferential direction of cooling tank 13 is formed. The refrigerant, whose flow pattern has been converted by conversion member 21, rotates along the circumferential direction of cooling tank 13 and flows from the bottom side to the top side of lead-in pipe 14, and is introduced into cooling tank 13 via cooling-tank-side opening 22a of lead-in pipe 14 and lower-end opening 13d of cooling tank 13. The refrigerant introduced into cooling tank 13 flows through cooling tank 13 while rotating in the circumferential direction of cooling tank 13 and forming a swirling flow that flows in the longitudinal direction of cooling tank 13. This swirling flow of the refrigerant causes workpiece 10 placed in cooling tank 13 to be uniformly cooled from the entire periphery of workpiece 10.

[0073] [Verification of the flow pattern of the refrigerant introduced into the cooling tank from the inlet pipe] The refrigerant flow patterns in the introduction pipe 14 and the cooling tank 13 of the heat treatment device 1 were analyzed by computer simulation. In the simulation analysis, the refrigerant flow patterns in the pipe main body 20 and the cooling tank 13 were analyzed for a comparative example and an example of this embodiment when the refrigerant was supplied to the pipe main body 20 under the same flow rate conditions. In the comparative example, the refrigerant flow patterns in the pipe main body 20 and the cooling tank 13 were analyzed under the condition that the converting member 21 was not installed in the pipe main body 20. On the other hand, in the example, the refrigerant flow patterns in the introduction pipe 14 and the cooling tank 13 equipped with the converting member 21 were analyzed under the condition that the converting member 21 was installed in the pipe main body 20. In addition, the analysis of the refrigerant flow patterns by simulation included analysis of the refrigerant flow streamlines in the pipe main body 20 and the cooling tank 13 and the flow velocity distribution of the refrigerant in the cooling tank 13.

[0074] Fig. 9 is a diagram showing the results of analyzing the flow lines of the refrigerant in a comparative example. Fig. 10 is a diagram showing the results of analyzing the flow lines of the refrigerant in an example. In Fig. 9 showing the comparative example, the flow lines of the refrigerant flowing through the pipe main body 20 and the cooling tank 13 are labeled F1. In Fig. 10 showing the example, the flow lines of the refrigerant flowing through the inlet pipe 14 and the cooling tank 13 are labeled F2.

[0075] 9, in the comparative example, when the refrigerant flows through pipe main body 20 and reaches the end of pipe main body 20, it passes through lower end opening 13d of cooling tank 13 and is introduced into cooling tank 13 connected to the end of pipe main body 20. When the refrigerant is introduced into cooling tank 13, the flow direction of the refrigerant is suddenly changed toward cooling tank 13, which is connected perpendicularly to pipe main body 20. Therefore, the refrigerant is introduced into cooling tank 13 in a turbulent state with an uneven flow velocity distribution. The refrigerant introduced into cooling tank 13 does not form a swirling flow within cooling tank 13, and flows upward through cooling tank 13 in a turbulent flow with an uneven flow velocity distribution.

[0076] 10 , in this embodiment, the refrigerant flowing through the inlet pipe 14 is changed by a conversion member 21 at the end of the inlet pipe 14 so that the flow direction of the refrigerant is changed to a direction along the longitudinal direction of the cooling tank 13 and the flow pattern is converted to form a refrigerant flow that rotates along the circumferential direction of the cooling tank 13. Then, the refrigerant whose flow pattern has been converted by the conversion member 21 is introduced into the cooling tank 13 and flows through the cooling tank 13 while forming a swirling flow that flows along the longitudinal direction of the cooling tank 13 while rotating along the circumferential direction of the cooling tank 13.

[0077] FIG. 11 is a diagram showing the results of analyzing the flow velocity distribution of the refrigerant in cooling tank 13 in a comparative example. FIG. 12 is a diagram showing the results of analyzing the flow velocity distribution of the refrigerant in cooling tank 13 in an example. Note that FIGS. 11 and 12 show the flow velocity distribution of the refrigerant in a horizontal cross section at three different height positions (H1, H2, H3) in cooling tank 13. The three height positions (H1, H2, H3) in cooling tank 13 are indicated by arrow positions H1, H2, and H3 in FIGS. 9 and 10, respectively. Height position H1 is the upper end position of cooling tank 13, height position H2 is a position near the center of cooling tank 13 in the height direction, and height position H3 is the lower end position of cooling tank 13. The flow velocity distribution of the refrigerant at each height position (H1, H2, H3) is shown in three stages of flow velocities (V1, V2, V3). Flow velocity V1 is the fastest of the three flow velocities, and the area where flow velocity V1 occurs is shown as a white area with no hatching. Flow velocity V2 is the second fastest of the three flow velocities, and the area where flow velocity V2 occurs is shown as a lightly hatched, light gray area. Flow velocity V3 is the slowest of the three flow velocities, and the area where flow velocity V3 occurs is shown as a heavily hatched, dark gray area.

[0078] In the comparative example, as shown in Fig. 11, the flow velocity distribution of the refrigerant varies greatly at each height position (H1, H2, H3), resulting in a non-uniform flow in the circumferential direction of cooling tank 13. On the other hand, in the example, as shown in Fig. 12, the flow velocity distribution of the refrigerant is similar at each height position (H1, H2, H3), resulting in a uniform flow in the circumferential direction of cooling tank 13.

[0079] As described above, the verification results demonstrated that in the heat treatment device 1 of this embodiment, the refrigerant flowing through the inlet pipe 14 has its flow pattern converted by the conversion member 21 and is introduced into the cooling tank 13, where it flows through the cooling tank 13 while forming a swirling flow that rotates along the circumferential direction of the cooling tank 13 and flows along the longitudinal direction of the cooling tank 13. Furthermore, it was demonstrated that in the heat treatment device 1 of this embodiment, the refrigerant has a similar flow velocity distribution at any height position in the cooling tank 13, and a uniform flow is formed in the circumferential direction of the cooling tank 13.

[0080] [Effects of this embodiment] As described above, in this embodiment, the refrigerant supplied to the inlet pipe 14 flows through the inlet pipe 14 and reaches the conversion member 21 disposed at the end of the inlet pipe 14 connected to the cooling tank 13. The refrigerant that reaches the conversion member 21 flows along the surface of the conversion member 21, which extends along the longitudinal direction of the cooling tank 13 from the bottom side to the top side of the inlet pipe 14, and the flow direction is changed from the longitudinal direction of the inlet pipe 14 to the longitudinal direction of the cooling tank 13. Furthermore, the refrigerant flows along the curved surfaces (25a, 26a, 27a) that are along the inner circumferential shape of the cooling tank 13 when viewed from the longitudinal direction of the cooling tank 13, and a refrigerant flow that rotates along the circumferential direction of the cooling tank 13 is formed. Therefore, the conversion member 21 changes the flow direction of the refrigerant and converts the refrigerant flow pattern so that a refrigerant flow that rotates along the circumferential direction of the cooling tank 13 is formed. The refrigerant, whose flow pattern has been converted by conversion member 21, rotates along the circumferential direction of cooling tank 13 and flows from the bottom side to the top side of introduction pipe 14, and is introduced into cooling tank 13 from introduction pipe 14. The refrigerant introduced into cooling tank 13 then flows through cooling tank 13 while rotating along the circumferential direction of cooling tank 13, forming a swirling flow that flows along the longitudinal direction of cooling tank 13. Due to this swirling flow of the refrigerant, workpiece 10 placed in cooling tank 13 is cooled uniformly from the entire periphery of workpiece 10.

[0081] Therefore, according to this embodiment, in the inlet pipe 14 connected to the cooling tank 13, a converting member 21 is provided that extends along the longitudinal direction of the cooling tank 13 and has curved surfaces (25a, 26a, 27a) that conform to the inner circumferential shape of the cooling tank 13 when viewed from the longitudinal direction of the cooling tank 13. This allows for the formation of a swirling flow that uniformly cools the workpiece 10 in the cooling tank 13. Therefore, according to this embodiment, when the refrigerant supplied from the inlet pipe 14 is introduced into the cooling tank 13 and the flow of the refrigerant flowing within the cooling tank 13 is formed as a swirling flow, there is no need to provide a structure that extends spirally along the inner circumferential direction of the cooling tank 13. Therefore, since there is no need to provide a structure that extends spirally long along the longitudinal direction of the cooling tank 13 to form a swirling flow, the cooling tank 13 can be shortened, and the overall configuration of the heat treatment apparatus 1 can be shortened.

[0082] Furthermore, according to this embodiment, the conversion member 21 is formed as a part that is curved and has surfaces (25a, 26a, 27a) that follow the inner peripheral shape of the cooling tank 13 when viewed from the longitudinal direction of the cooling tank 13, and extends between the bottom side and the top side of the inlet pipe 14, so that the part for forming a swirling flow in the cooling tank 13 can be manufactured with a simple structure.

[0083] Furthermore, according to this embodiment, the conversion member 21, which is a component for forming a swirling flow, is formed as a component with a simple structure that has curved surfaces (25a, 26a, 27a) that conform to the inner peripheral shape of the cooling tank 13 when viewed from the longitudinal direction of the cooling tank 13 and extends between the bottom and top sides of the inlet pipe 14, and can be installed at the end of the inlet pipe 14 that is connected to the cooling tank 13. Therefore, the component for forming a swirling flow can be easily fixed inside the device.

[0084] Furthermore, according to this embodiment, the refrigerant that has flowed through the inlet pipe 14 and reached the conversion member 21 flows so as to rotate along the surfaces (25a, 26a, 27a) that are arranged in a spiral shape when viewed from the longitudinal direction of the cooling tank 13. Therefore, the surfaces (25a, 26a, 27a) of the conversion member 21 can form a rotating flow of the refrigerant.

[0085] Furthermore, according to this embodiment, the refrigerant that has flowed through the inlet pipe 14 and reached the conversion member 21 flows so as to rotate along the multiple surfaces (25a, 26a, 27a) that are arranged in a spiral shape when viewed from the longitudinal direction of the cooling tank 13. Therefore, the multiple surfaces (25a, 26a, 27a) of the conversion member 21 can form a rotating flow of the refrigerant.

[0086] Furthermore, according to this embodiment, the refrigerant that has flowed through inlet pipe 14 and reached conversion member 21 flows so as to rotate along first surface 25a of conversion member 21, and then flows so as to rotate along second surface 26a. Therefore, a rotating flow of the refrigerant can be formed by first surface 25a and second surface 26a.

[0087] Furthermore, according to this embodiment, the refrigerant that has flowed through introduction pipe 14 and reached conversion member 21 flows so as to rotate along first surface 25a of conversion member 21, then flows so as to rotate along second surface 26a, and then further flows so as to rotate along third surface 27a. Therefore, first surface 25a, second surface 26a, and third surface 27a can form a more stable rotating flow of the refrigerant.

[0088] Furthermore, if conversion member 21 is made as a single piece, and if the size of conversion member 21 is larger than the opening between inlet pipe 14 and cooling tank 13, it will be difficult to insert and assemble conversion member 21 through the opening between inlet pipe 14 and cooling tank 13. However, according to this embodiment, conversion member 21 is provided as a divided part consisting of first member 23 and second member 24, so that conversion member 21 can be inserted and assembled through the opening between inlet pipe 14 and cooling tank 13.

[0089] [Variations] Although the present invention has been described above with reference to an embodiment, it is not limited to the above embodiment and can be implemented with various modifications within the scope of the claims. For example, the following modifications may be implemented. In the following description of the modifications, differences from the above embodiment will be described, and configurations similar to or corresponding to those of the above embodiment will be denoted by the same reference numerals in the drawings or by citing the same reference numerals, thereby omitting redundant description.

[0090] (1) In the above embodiment, the conversion member 21 is described as being divided into the first member 23 and the second member 24, but this need not be the case and an undivided, one-piece conversion member may be used. Fig. 13(A) is a perspective view showing a conversion member 21a according to a first modified example, and Fig. 13(B) is a plan view showing the conversion member 21a of the first modified example.

[0091] The conversion member 21a shown in FIGS. 13(A) and 13(B) is configured as a single component in which the first curved portion 25, the second curved portion 26, and the third curved portion 27 are integrally provided. A connecting portion 29 that connects the first curved portion 25 and the second curved portion 26 is provided between the first curved portion 25 and the second curved portion 26. The connecting portion 29 extends continuously from the first curved portion 25 and is connected continuously to the second curved portion 26. The connecting portion 29 is provided so as to extend linearly along the longitudinal direction of the introduction pipe 14 when viewed from the longitudinal direction of the cooling tank 13. Therefore, the conversion member 21a is provided so that the first curved portion 25, the connecting portion 29, the second curved portion 26, the connecting portion 28, and the third curved portion 27 are integrally provided so as to extend continuously in this order.

[0092] Similarly to the conversion member 21 of the above-described embodiment, the conversion member 21a extends along the longitudinal direction of the cooling tank 13 between the bottom surface side and the top surface side of the introduction pipe 14, and has curved surfaces (25a, 26a, 27a) that follow the inner peripheral shape of the cooling tank 13. The multiple surfaces (25a, 26a, 27a) of the conversion member 21a are arranged in a spiral shape when viewed from the longitudinal direction of the cooling tank 13.

[0093] When assembling the conversion member 21a of the first modified example in the heat treatment apparatus 1, the cooling tank side opening 22a of the pipe body 20 of the introduction pipe 14 may be formed large enough to allow the integral conversion member 21a to pass through, and the conversion member 21a may be installed on the pipe body 20 together with a cover member that closes the cooling tank side opening 22a. Figures 14(A) and 14(B) are perspective views illustrating an assembled form of the introduction pipe 14 and cooling tank 13 equipped with the conversion member 21a of the first modified example.

[0094] 14(A), when the conversion member 21a is assembled to the heat treatment apparatus 1, the conversion member 21a is fixed to a plate-shaped lid member 30 for closing the cooling tank side opening 22a of the pipe main body 20. The conversion member 21a is fixed to the lid member 30 by, for example, welding. The lid member 30 has a through-hole 30a penetrating the lid member 30 at a position corresponding to an area where the second surface 26a and the third surface 27a of the fixed conversion member 21a are arranged facing each other.

[0095] 14(B), when the conversion member 21a is fixed to the lid member 30, the lid member 30 to which the conversion member 21a is fixed is fixed to the upper wall 20a of the pipe body 20. At this time, with the conversion member 21a inserted into the pipe body 20 from the cooling tank side opening 22a of the pipe body 20, the outer peripheral edge of the lid member 30 is welded to the outer peripheral edge of the cooling tank side opening 22a in the upper wall 20a, thereby fixing the lid member 30 to the upper wall 20a.

[0096] Once the lid member 30 with the converting member 21a fixed thereto is fixed to the pipe body 20, the bottom wall 13b of the cooling tank 13 is then fixed to the upper wall 20a of the pipe body 20 of the inlet pipe 14. The bottom wall 13b of the cooling tank 13 is fixed to the upper wall 20a of the pipe body 20, for example, by welding. The lower end opening 13d of the bottom wall 13b of the cooling tank 13 is formed to be large enough to fit the lid member 30 therein, and further formed to be large enough to fit within the range of the upper wall 20a of the pipe body 20 in the width and length directions.

[0097] In the heat treatment device 1 provided with the conversion member 21a of the first modification, when the refrigerant flows through the inlet pipe 14 and reaches the conversion member 21a, it flows along the surfaces (25a, 26a, 27a) of the conversion member 21a. This changes the flow direction of the refrigerant to a flow along the longitudinal direction of the cooling tank 13, and converts the flow pattern of the refrigerant to a flow that rotates along the circumferential direction of the cooling tank 13. The refrigerant, whose flow pattern has been converted by the conversion member 21a, rotates along the circumferential direction of the cooling tank 13 and flows from the bottom side to the top side of the inlet pipe 14, and is introduced into the cooling tank 13 through the through hole 30a of the lid member 30 and the lower end opening 13d of the cooling tank 13. The refrigerant introduced into the cooling tank 13 flows through the cooling tank 13 while forming a swirling flow that rotates along the circumferential direction of the cooling tank 13 and flows along the longitudinal direction of the cooling tank 13.

[0098] As described above, the conversion member 21a may be configured as a single integral part in which the first curved portion 25, the second curved portion 26, and the third curved portion 27 are integrally provided.

[0099] (2) In the above embodiment, the conversion member 21 is divided into the first member 23 having the first surface 25a and the second member 24 having the second surface 26a and the third surface 27a. However, the conversion member need not be divided in this manner. The conversion member may be divided into various types of divided members. For example, the conversion member may have the shapes shown in Figures 15(A) to 15(C) as examples.

[0100] 15(A) is a plan view showing conversion member 21b according to a second modified example. Conversion member 21b is configured by being divided into three divided members, namely, first divided member 31, second divided member 32, and third divided member 33. First divided member 31, second divided member 32, and third divided member 33 are all provided to extend along the longitudinal direction of cooling tank 13 between the bottom and top sides of introduction pipe 14.

[0101] The first divided member 31 is formed similarly to the first member 23 and has a first curved portion 25 and a first surface 25a. The second divided member 32 is configured with a second curved portion 26 and a second surface 26a. The third divided member 33 is configured with a third curved portion 27 and a third surface 27a. Note that the connecting portion 28 of the above embodiment is not provided between the second divided member 32 and the third divided member 33, and the second divided member 32 and the third divided member 33 are provided as separate members.

[0102] Conversion member 21b includes a first divided member 31 having a first surface 25a, a second divided member 32 having a second surface 26a, and a third divided member 33 having a third surface 27a. Therefore, conversion member 21b includes curved surfaces (25a, 26a, 27a) that conform to the inner circumferential shape of cooling tank 13. The multiple surfaces (25a, 26a, 27a) of conversion member 21b are arranged in a spiral shape when viewed from the longitudinal direction of cooling tank 13.

[0103] In heat treatment device 1 provided with conversion member 21b of the second modified example, the refrigerant flows along surfaces (25a, 26a, 27a) of conversion member 21b at the end of introduction pipe 14, whereby the flow pattern is converted, and the refrigerant is introduced into cooling tank 13. By converting the flow pattern of the refrigerant by conversion member 21b, a swirling flow that flows along the longitudinal direction of cooling tank 13 while rotating along the circumferential direction of cooling tank 13 is formed.

[0104] 15(B) is a plan view showing conversion member 21c according to a third modified example. Conversion member 21c is configured by being divided into three divided members, namely, first divided member 31a, second divided member 32a, and third divided member 33a. First divided member 31a, second divided member 32a, and third divided member 33a are all provided to extend along the longitudinal direction of cooling tank 13 between the bottom and top sides of introduction pipe 14.

[0105] The first divided member 31a, the second divided member 32a, and the third divided member 33a are all disposed inside the pipe body 20 at the end of the pipe body 20 that is connected to the cooling tank 13. At the end of the pipe body 20 that is connected to the cooling tank 13, the first divided member 31a is disposed adjacent to the end wall 20e, and the second divided member 32a and the third divided member 33a are disposed on the opposite side of the first divided member 31a from the end wall 20e. Furthermore, the second divided member 32a is disposed adjacent to the side wall 20d, and the third divided member 33a is disposed on the side of the second divided member 32a that is closer to the side wall 20c and spaced apart from the side wall 20c.

[0106] The first divided member 31a is formed in the same manner as the first member 23, and has a first curved portion 25 and a first surface 25a.

[0107] The second divided member 32a includes a curved portion 34 that extends in an arc shape in the circumferential direction from the side wall 20d toward the center of the lead-in pipe 14 in the width direction at an angle of approximately 90° when viewed from the longitudinal direction of the cooling tank 13. The curved portion 34 is formed to extend in an arc shape toward the side wall 20d and also toward the opposite side from the end wall 20e. The curved portion 34 that extends in an arc shape is arranged to extend along the inner circumferential shape of the cooling tank 13, which is circular, when viewed from the longitudinal direction of the cooling tank 13. Therefore, the curved inner surface 34a of the curved portion 34 of the second divided member 32a is configured as a curved surface 34a that follows the inner circumferential shape of the cooling tank 13 when viewed from the longitudinal direction of the cooling tank 13.

[0108] The third divided member 33a is configured to include a curved portion 35 that extends in an arc shape toward the sidewall 20c when viewed from the longitudinal direction of the cooling tank 13. The curved portion 35 is formed to extend in an arc shape over an angle of approximately 180° in the circumferential direction. The curved portion 35 extends in an arc shape concentrically with the inner circumferential shape of the circular cooling tank 13, centered on the central axis of the cooling tank 13, when viewed from the longitudinal direction of the cooling tank 13. Therefore, the curved portion 35 extending in an arc shape is arranged to extend concentrically with the inner circumferential shape of the cooling tank 13 and along the inner circumferential shape of the cooling tank 13 when viewed from the longitudinal direction of the cooling tank 13. Therefore, the curved inner surface 35a of the curved portion 35 of the third divided member 33a is configured as a curved surface 35a that follows the inner circumferential shape of the cooling tank 13 when viewed from the longitudinal direction of the cooling tank 13.

[0109] Conversion member 21c includes first divided member 31a having surface 25a, second divided member 32a having surface 34a, and third divided member 33a having surface 35a. Therefore, conversion member 21c includes curved surfaces (25a, 34a, 35a) that conform to the inner circumferential shape of cooling tank 13. The multiple surfaces (25a, 34a, 35a) of conversion member 21c are arranged in a spiral shape when viewed from the longitudinal direction of cooling tank 13.

[0110] In heat treatment apparatus 1 provided with conversion member 21c of the third modified example, the refrigerant flows along the surfaces (25a, 34a, 35a) of conversion member 21c at the end of introduction pipe 14, whereby the flow pattern is converted, and the refrigerant is introduced into cooling tank 13. By converting the flow pattern of the refrigerant by conversion member 21c, a swirling flow that flows along the longitudinal direction of cooling tank 13 while rotating along the circumferential direction of cooling tank 13 is formed.

[0111] 15(C) is a plan view showing conversion member 21d according to a fourth modified example. Conversion member 21d is configured by being divided into two divided members, a first divided member 31b and a second divided member 32b. First divided member 31b and second divided member 32b are both provided to extend along the longitudinal direction of cooling tank 13 between the bottom and top sides of introduction pipe 14.

[0112] First divided member 31b is provided as a member configured by integrating first divided member 31a and second divided member 32a of conversion member 21c according to the third modified example. That is, first divided member 31b is configured with first curved portion 25 provided with curved surface 25a and curved portion 34 provided with curved surface 34a. Second divided member 32b is formed similarly to third divided member 33a of conversion member 21c according to the third modified example, and has curved portion 35 and curved surface 35a.

[0113] Like the conversion member 21c of the third modified example, the conversion member 21c has curved surfaces (25a, 34a, 35a) that follow the inner circumferential shape of the cooling tank 13. The multiple surfaces (25a, 34a, 35a) of the conversion member 21c are arranged in a spiral shape when viewed from the longitudinal direction of the cooling tank 13.

[0114] In heat treatment device 1 provided with conversion member 21d of the fourth modification, the refrigerant flows along surfaces (25a, 34a, 35a) of conversion member 21d at the end of introduction pipe 14, whereby the flow pattern is converted, and the refrigerant is introduced into cooling tank 13. The conversion of the flow pattern of the refrigerant by conversion member 21d forms a swirling flow that flows along the longitudinal direction of cooling tank 13 while rotating along the circumferential direction of cooling tank 13.

[0115] (3) In the above embodiment, the conversion member 21 is described as having curved surfaces (25a, 26a, 27a) that conform to the inner circumferential shape of the cooling tank 13. However, this is not necessarily the case. A conversion member having a curved surface that conforms to the inner circumferential shape of the cooling tank 13 may also be implemented.

[0116] 16 is a plan view showing a conversion member 21e according to a fifth modified example. The conversion member 21e is configured to include a first member 23a and a second member 24a. The first member 23a and the second member 24a are both disposed inside the tube body 20, at the end of the tube body 20 that is connected to the cooling tank 13. At the end of the tube body 20 that is connected to the cooling tank 13, the first member 23a is disposed adjacent to the end wall 20e, and the second member 24a is disposed on the opposite side of the first member 23a from the end wall 20e.

[0117] The first member 23a and the second member 24a are both provided as plate-like members having bent portions, and are provided so as to extend along the longitudinal direction of the cooling tank 13 between the bottom surface side and the top surface side of the pipe body 20 of the introduction pipe 14.

[0118] The first member 23a has a first bent portion 36 that, when viewed from the longitudinal direction of the cooling tank 13, bends and extends in a convex shape toward the end wall 20e, which is the end side of the introduction pipe 14. The bent and extended first bent portion 36 of the first member 23a is arranged to extend while bending along the inner circumferential shape of the cooling tank 13, when viewed from the longitudinal direction of the cooling tank 13. Because the first bent portion 36 is configured as described above, the bent inner surface 36a of the first bent portion 36, i.e., the surface 36a of the first bent portion 36 facing the side opposite to the end wall 20e, is configured as a bent surface 36a that follows the inner circumferential shape of the cooling tank 13, when viewed from the longitudinal direction of the cooling tank 13. The surface 36a of the first bent portion 36 is arranged to be bent so as to be recessed toward the end wall 20a, which is the end side of the introduction pipe 14. The surface 36a of the first bent portion 36 constitutes a first surface that is bent so as to be recessed toward the end of the introduction pipe 14.

[0119] The second member 24a has a second bent portion 37, a third bent portion , and a connecting portion 39 that connects the second bent portion 37 and the third bent portion .

[0120] The second bent portion 37 of the second member 24a is disposed at a position opposite the first bent portion 36 of the first member 23a across the central axis direction of the cooling tank 13. The central axis direction of the cooling tank 13 is indicated by point P in FIG. 16 . The width of the second bent portion 37 opposite the first bent portion 36 is set smaller than the width of the first bent portion 36. More specifically, the width of the second bent portion 37, i.e., the length of the second bent portion 37 in the width direction of the introduction pipe 14, is set smaller than the width of the first bent portion 36, i.e., the length of the first bent portion 36 in the width direction of the introduction pipe 14. Furthermore, when viewed from the longitudinal direction of the cooling tank 13, the second bent portion 37 bends and extends in a convex shape toward the side opposite the end wall 20e, which is the end side of the introduction pipe 14. Therefore, the second bent portion 37 is bent and extends so as to protrude convexly toward the side opposite to the side where the first bent portion 36 protrudes convexly. The bent and extending second bent portion 37 is arranged so as to extend along the inner circumferential shape of the cooling tank 13 when viewed from the longitudinal direction of the cooling tank 13.

[0121] Because the second bent portion 37 is configured as described above, the bent inner surface 37a of the second bent portion 37, i.e., the surface 37a of the second bent portion 37 facing the end wall 20a, is configured as a bent surface 37a that follows the inner circumferential shape of the cooling tank 13 when viewed from the longitudinal direction of the cooling tank 13. The surface 37a of the second bent portion 37 is disposed at a position facing the surface 36a of the first bent portion 36 across the central axis direction of the cooling tank 13, and is bent so as to be recessed toward the side opposite the surface 36a of the first bent portion 36. The surface 37a of the second bent portion 37 is disposed at a position facing the surface 36a (first surface 36a) of the first bent portion 36 across the central axis direction of the cooling tank 13, and constitutes a second surface that is bent so as to be recessed toward the side opposite the surface 36a (first surface 36a).

[0122] The third bent portion 38 of the second member 24a is disposed between the first bent portion 36 of the first member 23a and the second bent portion 37 of the second member 24a, facing the second bent portion 37. The width of the third bent portion 38 facing the second bent portion 37 is set smaller than the width of the second bent portion 37. More specifically, the width of the third bent portion 38, i.e., the length of the third bent portion 38 in the width direction of the inlet pipe 14, is set smaller than the width of the second bent portion 37, i.e., the length of the second bent portion 37 in the width direction of the inlet pipe 14. Furthermore, when viewed from the longitudinal direction of the cooling tank 13, the third bent portion 38 is bent and extends so as to protrude convexly toward the end wall 20e, which is the end side of the inlet pipe 14. Therefore, the third bent portion 38 is bent and extends so as to protrude convexly toward the same side as the first bent portion 36. Furthermore, the third bent portion 38 is disposed between the central axis direction of the cooling tank 13 and the first bent portion 36 when viewed from the longitudinal direction of the cooling tank 13. Furthermore, the third bent portion 38 is disposed so as to extend while bending concentrically with the inner circumferential shape of the circular cooling tank 13 when viewed from the longitudinal direction of the cooling tank 13. Therefore, the third bent portion 38 is disposed so as to extend while bending concentrically with the inner circumferential shape of the cooling tank 13 when viewed from the longitudinal direction of the cooling tank 13.

[0123] Because the third bent portion 38 is configured as described above, the bent inner surface 38a of the third bent portion 38, i.e., the surface 38a of the third bent portion 38 facing the second bent portion 37, is configured as a bent surface 38a that is concentric with the inner circumferential shape of the cooling tank 13 when viewed from the longitudinal direction of the cooling tank 13. The surface 38a of the third bent portion 38 is disposed in a position facing the surface 37a of the second bent portion 37 between the surface 36a of the first bent portion 36 and the surface 37a of the second bent portion 37, and is disposed so as to be bent in a concave direction toward the opposite side to the surface 37a of the second bent portion 37. The surface 38a of the third bent portion 38 is positioned opposite the surface 37a (second surface 37a) between the surface 36a (first surface 36a) of the first bent portion 36 and the surface 37a (second surface 37a) of the second bent portion 37, and forms a third surface that is bent so as to be concave toward the opposite side of the surface 37a (second surface 37a).

[0124] The connecting portion 39 is provided in the second member 24a as a portion that connects the second bent portion 37 and the third bent portion 38. The connecting portion 39 extends continuously from the second bent portion 37 and is continuously connected to the third bent portion 38. The connecting portion 39 is provided to extend from the end of the second bent portion 37 to a position approximately midway between the second bent portion 37 and the first bent portion 36. The connecting portion 39 is provided to extend linearly along the longitudinal direction of the introduction pipe 14 when viewed from the longitudinal direction of the cooling tank 13.

[0125] As described above, the first member 23a has a curved surface 36a that follows the inner circumferential shape of the cooling tank 13 when viewed from the longitudinal direction of the cooling tank 13. The second member 24a has curved surfaces (37a, 38a) that follow the inner circumferential shape of the cooling tank 13 when viewed from the longitudinal direction of the cooling tank 13. Therefore, the conversion member 21e, which includes the first member 23a and the second member 24a, has curved surfaces (36a, 37a, 38a) that follow the inner circumferential shape of the cooling tank 13 when viewed from the longitudinal direction of the cooling tank 13.

[0126] Furthermore, the surfaces (36a, 37a, 38a) of the conversion member 21e are arranged in a spiral shape when viewed from the longitudinal direction of the cooling tank 13. The conversion member 21e has a plurality of surfaces (36a, 37a, 38a), and the surfaces (36a, 37a, 38a) are arranged in a spiral shape when viewed from the longitudinal direction of the cooling tank 13. The surfaces (36a, 37a, 38a) are arranged in the order of surface 36a, surface 37a, and surface 38a in a spiral shape that decreases in diameter from the outer periphery to the inner periphery when viewed from the longitudinal direction of the cooling tank 13.

[0127] In heat treatment device 1 provided with conversion member 21e of the fifth modification, the refrigerant flows along surfaces (36a, 37a, 38a) of conversion member 21e at the end of introduction pipe 14, whereby the flow pattern is converted, and the refrigerant is introduced into cooling tank 13. The conversion of the flow pattern of the refrigerant by conversion member 21e forms a swirling flow that flows along the longitudinal direction of cooling tank 13 while rotating along the circumferential direction of cooling tank 13.

[0128] (4) In the above embodiment, the conversion member 21 includes the first member 23 and the second member 24 formed in a plate shape, and the first member 23 and the second member 24 have curved surfaces (25a, 26a, 27a) that conform to the inner peripheral shape of the cooling tank 13. However, this is not necessarily the case. For example, the conversion member may be formed as a block-shaped member instead of a plate-shaped member.

[0129] FIG. 17 is a perspective view showing a conversion member 21f according to a sixth modified example. The conversion member 21f includes a first member 23b and a second member 24b. The first member 23b is provided as a flocked member and is formed, for example, as a casting. The first member 23b has a curved surface 25a having the same shape as the curved surface 25a of the first member 23 of the previous embodiment. The second member 24b is provided as a flocked member and is formed, for example, as a casting. The second member 24b has curved surfaces (26a, 27a) having the same shape as the curved surfaces (26a, 27a) of the second member 24 of the previous embodiment. Because the first member 23b and the second member 24b are configured as described above, the conversion member 21f including the block-shaped first member 23b and second member 24b has curved surfaces (25a, 26a, 27a) that follow the inner circumferential shape of the cooling tank 13 when viewed from the longitudinal direction of the cooling tank 13. In addition, the surfaces (25a, 26a, 27a) of the conversion member 21f are arranged in a spiral shape when viewed from the longitudinal direction of the cooling tank 13.

[0130] In heat treatment device 1 provided with conversion member 21f of the sixth modification, the refrigerant flows along the surfaces (25a, 26a, 27a) of conversion member 21f at the end of introduction pipe 14, whereby the flow pattern is converted, and the refrigerant is introduced into cooling tank 13. The conversion of the flow pattern of the refrigerant by conversion member 21f forms a swirling flow that flows along the longitudinal direction of cooling tank 13 while rotating along the circumferential direction of cooling tank 13.

[0131] (5) In the above-described embodiment and modified example, the curved or bent surface of the conversion member for forming a swirling flow, which is arranged spirally as viewed from the longitudinal direction of the cooling tank, is arranged spirally with a diameter that decreases clockwise from the outer circumferential side to the inner circumferential side as viewed from the cooling tank side, but this is not necessarily the case. Alternatively, the curved or bent surface of the conversion member, which is arranged spirally as viewed from the longitudinal direction of the cooling tank, may be arranged spirally with a diameter that decreases counterclockwise from the outer circumferential side to the inner circumferential side as viewed from the cooling tank side.

[0132] (6) In the above embodiment, the curved surfaces (25a, 26a, 27a) that conform to the inner peripheral shape of the cooling tank 13 when viewed from the longitudinal direction of the cooling tank 13 are arranged along concentric circles whose centers are coaxial with the circumference of the inner peripheral shape of the cooling tank 13 when viewed from the longitudinal direction of the cooling tank 13. However, this is not necessarily the case. The center of the circle on which the curved surfaces (25a, 26a, 27a) are arranged when viewed from the longitudinal direction of the cooling tank 13 may be set to be slightly offset from the center of the circumference of the inner peripheral shape of the cooling tank 13. For example, when the axial center of the workpiece 10 placed in the cooling tank 13 is slightly offset from the center of the circumference of the inner peripheral shape of the cooling tank 13, the conversion member 21 may be installed so that the center of the circle on which the curved surfaces (25a, 26a, 27a) are arranged coincides with the axial center of the workpiece 10.

[0133] (7) In the above embodiment, the curved surface that conforms to the inner peripheral shape of the cooling tank when viewed from the longitudinal direction of the cooling tank is curved in an arc shape, but this is not necessarily the case. For example, the curved surface that conforms to the inner peripheral shape of the cooling tank when viewed from the longitudinal direction of the cooling tank may be curved in an elliptical shape.

[0134] (8) In the above embodiment, the pipe body of the introduction pipe is described as a rectangular tubular member with a rectangular cross section, but this is not necessarily the case. The pipe body of the introduction pipe may be a tubular member with a cross section other than rectangular, for example, a cylindrical member with a circular cross section. [Industrial Applicability]

[0135] The present invention can be widely applied as a heat treatment apparatus that supplies a coolant to an object to be treated and performs heat treatment thereon. [Explanation of symbols]

[0136] 1. Heat treatment equipment 10. Material to be processed 13 Cooling tank 14 Introductory tube 21, 21a, 21b, 21c, 21d, 21e, 21f conversion members 23, 23a, 23b First member 24, 24a, 24b Second member 25a, 26a, 27a, 34a, 35a, 36a, 37a, 38a side

Claims

1. a cylindrical cooling tank in which the object to be treated is placed; an introduction pipe for introducing a refrigerant for heat treatment of the object to be treated into the cooling tank; In a heat treatment apparatus in which the cooling tank and the introduction pipe are connected in a direction in which the longitudinal direction of the cooling tank and the longitudinal direction of the introduction pipe are different from each other, the inlet pipe includes a converting member at an end connected to the cooling tank that changes the direction of the refrigerant flow and causes the refrigerant flow to rotate in a circumferential direction of the cooling tank; The conversion member extends along the longitudinal direction of the cooling tank between the bottom side and the top side of the inlet pipe, and has a curved or bent surface that follows the inner circumferential shape of the cooling tank when viewed from the longitudinal direction of the cooling tank.

2. 2. The heat treatment apparatus according to claim 1, The surface is arranged in a spiral shape when viewed from the longitudinal direction of the cooling tank.

3. The heat treatment apparatus according to claim 2, The surface is provided in plurality, The plurality of surfaces are arranged in a spiral shape when viewed from the longitudinal direction of the cooling tank.

4. The heat treatment apparatus according to claim 3, The conversion member is a first surface configured as the surface and curved or bent so as to be recessed toward the end of the introduction pipe; a second surface configured as the surface, disposed at a position opposite to the first surface across the central axis direction of the cooling tank, and curved or bent so as to be recessed toward an opposite side to the first surface; A heat treatment device comprising:

5. The heat treatment apparatus according to claim 4, The conversion member is configured as the surface, and is arranged between the first surface and the second surface at a position facing the second surface, and is arranged curved or bent so as to be concave toward the side opposite the second surface.

6. A heat treatment apparatus according to claim 4 or claim 5, The conversion member is a first member extending along the longitudinal direction of the cooling tank between the bottom surface side and the top surface side of the inlet pipe, and having the first surface; a second member extending along the longitudinal direction of the cooling tank between the bottom surface side and the top surface side of the inlet pipe, and having the second surface; A heat treatment device comprising:

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