Method for forming refrigerant flow passage, method for producing structure that has refrigerant flow passage, and machine tool

Abstract

This method for forming a refrigerant flow pasage comprises: a step for preparing a case that has a recess defined by a side wall and an end wall, and a groove formed in an outer surface of the end wall, and a cover that covers the groove; a step for joining the case and the cover by friction stirring, such that a refrigerant flow passage is formed by the groove and the cover; and a step for discharging a liquid coolant from an applicator to the case during the friction stirring.

Description

Method for forming a refrigerant flow path, method for manufacturing a structure having the refrigerant flow path, and machine tool 【0001】 The present invention relates to a method for forming a refrigerant flow path, a method for manufacturing a structure having the refrigerant flow path, and a machine tool. 【0002】 A friction stir welding apparatus provided with a cooling means is known. 【0003】 As a related technique, Patent Document 1 discloses a friction stir welding apparatus. The friction stir welding apparatus described in Patent Document 1 includes a cooling means disposed above the base material. The cooling means includes a first cooling means for injecting a refrigerant at a front position on the joining line and a second cooling means for cooling the weld bead. 【0004】 Japanese Patent Application Laid-Open No. 2004-148350 【0005】 An object of the present invention is to provide a method for forming a refrigerant flow path in which distortion of a case due to heat generated by friction stir is suppressed, a method for manufacturing a structure having the refrigerant flow path, and a machine tool. 【0006】 Embodiments of the present invention relate to the following method for forming a refrigerant flow path, method for manufacturing a structure having the refrigerant flow path, and machine tool. 【0007】(1) A method for forming a refrigerant channel, comprising the steps of: preparing a case having a recess defined by a side wall and an end wall and a groove formed on the outer surface of the end wall, and a cover covering the groove; joining the case and the cover by friction stirring so that a refrigerant channel is formed by the groove and the cover; and discharging coolant from an applicator into the case while the friction stirring is being performed. (2) A method for manufacturing a structure having a refrigerant channel, comprising the steps of: preparing a case having a recess defined by a side wall and an end wall and a groove formed on the outer surface of the end wall, and a cover covering the groove; joining the case and the cover by friction stirring so that a refrigerant channel is formed by the groove and the cover; discharging coolant from an applicator into the case while the friction stirring is being performed; placing an object to be cooled in the recess; and fixing a lid to the case so that the recess is closed by the lid. (3) A machine tool comprising: a work support device that supports a case having a recess defined by a side wall and an end wall and a groove formed on the outer surface of the end wall and a cover covering the groove; a spindle capable of holding a friction stir joining tool for joining the case and the cover by friction stir such that a coolant flow path is formed by the groove and the cover; a support that supports the spindle so as to be rotatable about a first axis; a rotation drive device for rotating the spindle about the first axis; a moving device for moving the spindle and the support relative to the work support device; a supply device for supplying coolant to an applicator; and an applicator for discharging the coolant into the case during the execution of the friction stir. 【0008】 The present invention provides a method for forming a refrigerant channel that suppresses distortion of the case due to heat generated by frictional stirring, a method for manufacturing a structure having a refrigerant channel, and a machine tool. 【0009】Figure 1 is a schematic perspective view illustrating an example of a case and cover prepared in the preparation process. Figure 2 is a schematic perspective view illustrating an example of a case prepared in the preparation process. Figure 3 is a schematic perspective view illustrating an example of a case and cover prepared in the preparation process. Figure 4 is a schematic cross-sectional view illustrating the state in which the cover is placed on the case. Figure 5 is an enlarged view of the area enclosed by the dashed circle B in Figure 4. Figure 6 is a schematic cross-sectional view illustrating the execution of the joining process. Figure 7 is a schematic perspective view illustrating another example of a case and cover prepared in the preparation process. Figure 8 is a schematic perspective view illustrating yet another example of a case and cover prepared in the preparation process. Figure 9 is a schematic perspective view illustrating the state in which the case and cover are supported by the workpiece support device. Figure 10 is a schematic perspective view illustrating the state in which the case and cover are supported by the workpiece support device. Figure 11 is a schematic cross-sectional view illustrating the state in which the case and cover are supported by the workpiece support device. Figure 12 is a schematic cross-sectional view illustrating the joining process in progress. Figure 13 is a schematic cross-sectional view illustrating the joining process in progress. Figure 14 is a schematic cross-sectional view illustrating how the height of the first end of the first support column can be adjusted. Figure 15 is a schematic cross-sectional view illustrating how the height of the second end of the second support column can be adjusted. Figure 16 is a schematic front view illustrating the state in which the case and cover are supported by the work support device. Figure 17 is a schematic perspective view illustrating the joining process in progress. Figure 18 is a schematic perspective view illustrating the joining process in progress. Figure 19 is a schematic perspective view illustrating the joining process in progress. Figure 20 is a schematic perspective view illustrating the joining process in progress. Figure 21 is a diagram for explaining the first path. Figure 22 is a schematic cross-sectional view illustrating the joining process in progress. Figure 23 is a schematic perspective view illustrating an example of a jig for supporting the case and cover. Figure 24 is a schematic cross-sectional view illustrating the joining process. Figure 25 is a schematic front view illustrating the cutting process. Figure 26 is a schematic perspective view illustrating the cutting process.Figure 27 is a schematic perspective view showing the object to be cooled placed in the recess of the case. Figure 28 is a schematic perspective view showing the lid being attached to the case. Figure 29 is a flowchart showing an example of a method for forming a refrigerant flow path in the first embodiment. Figure 30 is a schematic front view showing a part of the machine tool in the first embodiment. Figure 31 is a schematic perspective view showing an example of a jig supporting the case and cover. Figure 32 is a diagram illustrating an example of a spray nozzle. Figure 33 is a schematic perspective view showing the machine tool in the first embodiment. Figure 34 is a schematic perspective view showing the machine tool in the first embodiment. Figure 35 is a schematic front view showing a part of the machine tool in the first embodiment. Figure 36 is a schematic diagram showing how the control device can control multiple controlled devices. 【0010】 The following description of the embodiment will refer to the drawings and explain the method for forming the refrigerant flow path, the method for manufacturing a structure having a refrigerant flow path, and the machine tool. In the following description of the embodiment, parts and components having the same function will be denoted by the same reference numeral, and repeated descriptions of parts and components denoted by the same reference numeral will be omitted. 【0011】 (Definition of Terms) In this specification, the direction in which the case 7 and cover 8 are pressed by the friction stir welding tool T1 is defined as the first direction DR1. The direction opposite to the first direction DR1 is defined as the second direction DR2. 【0012】 The first direction DR1 may be downward (more specifically, vertically downward) or lateral (more specifically, horizontal). For example, if machine tool 1 is a vertical machining center, the first direction DR1 is downward (more specifically, vertically downward). For example, if machine tool 1 is a horizontal machining center, the first direction DR1 is lateral (more specifically, horizontal). 【0013】(First Embodiment) Referring to Figures 1 to 29, a method for forming a refrigerant flow path and a method for manufacturing a structure having a refrigerant flow path in the first embodiment will be described. Figure 1 is a schematic perspective view showing an example of a case 7 and cover 8 prepared in the preparation step. Figure 2 is a schematic perspective view showing an example of a case 7 prepared in the preparation step. Figure 3 is a schematic perspective view showing an example of a case 7 and cover 8 prepared in the preparation step. Figure 4 is a schematic cross-sectional view showing the state in which the cover 8 is placed on the case 7. Figure 5 is an enlarged view of the area enclosed by the dashed circle B in Figure 4. Figure 6 is a schematic cross-sectional view showing the state in which the joining step is being performed. Figure 7 is a schematic perspective view showing another example of a case 7 and cover 8 prepared in the preparation step. Figure 8 is a schematic perspective view showing yet another example of a case 7 and cover 8 prepared in the preparation step. Figures 9 and 10 are schematic perspective views showing the state in which the case 7 and cover 8 are supported by the work support device 3. Figure 11 is a schematic cross-sectional view showing the case 7 and cover 8 supported by the workpiece support device 3. Figure 12 is a schematic cross-sectional view showing the joining process being performed. Figure 13 is a schematic cross-sectional view showing the joining process being performed. Figure 14 is a schematic cross-sectional view showing how the height of the first end 42a-1 of the first support column 42-1 can be adjusted. Figure 15 is a schematic cross-sectional view showing how the height of the second end 42a-2 of the second support column 42-2 can be adjusted. Figure 16 is a schematic front view showing the case 7 and cover 8 supported by the workpiece support device 3. Figures 17 to 20 are schematic perspective views showing the joining process being performed. Figure 21 is a diagram for explaining the first path PA. Figure 22 is a schematic cross-sectional view showing how the joining process is being performed. Figure 23 is a schematic perspective view showing an example of a jig 4 that supports the case 7 and cover 8. Figure 24 is a schematic cross-sectional view illustrating the joining process. Figure 25 is a schematic front view illustrating the cutting process. Figure 26 is a schematic perspective view illustrating the cutting process.Figure 27 is a schematic perspective view showing the object to be cooled OB placed in the recess 74 of case 7. Figure 28 is a schematic perspective view showing the lid CB being attached to case 7. Figure 29 is a flowchart showing an example of a method for forming a refrigerant flow path in the first embodiment. 【0014】 As illustrated in Figure 1, the method for forming the refrigerant flow path in the first embodiment includes a step of preparing the case 7 and the cover 8 (hereinafter referred to as the "preparation step"). 【0015】 As illustrated in Figure 2, the case 7 prepared in the preparation step has a recess 74 defined by the side wall 71 and the end wall 73. 【0016】 As illustrated in Figure 1, the case 7 prepared in the preparation step has a groove 73v formed on the outer surface 73t of the end wall 73. In the examples shown in Figures 1 and 2, the groove 73v is located on the opposite side of the recess 74 with respect to the end wall 73. More specifically, the groove 73v is formed on the outer surface 73t of the end wall 73, and the inner surface 73n of the end wall 73 defines the bottom surface of the recess 74. 【0017】 As illustrated in Figures 1 and 3, the cover 8 prepared in the preparation step can cover the groove 73v described above. 【0018】 As illustrated in Figure 6, the method for forming a refrigerant flow path in the first embodiment includes a step of joining the case 7 and the cover 8 by friction stirring (hereinafter referred to as the "joining step") such that a refrigerant flow path 91 is formed by the groove 73v and the cover 8. 【0019】 As illustrated in Figure 6, the method for forming a refrigerant flow path in the first embodiment includes a step of releasing coolant L1 from the applicator 60 into the case 7 during friction stirring (hereinafter referred to as the "coolant release step"). 【0020】 In the coolant discharge process, while friction stirring is being performed, the coolant L1 is discharged onto at least one of the inner surface 71n of the side wall 71, the inner surface 73n of the end wall 73, and the outer surface 71t of the side wall 71. 【0021】In the first embodiment, since the coolant L1 is released into the case 7 during frictional stirring, distortion of the case 7 due to the heat generated by frictional stirring is suppressed. 【0022】 In the example shown in Figure 6, during friction stirring, the applicator 60 (more specifically, at least one nozzle 61) discharges the coolant L1 only to the case 7 of the case 7 and cover 8. More specifically, during friction stirring, the applicator 60 (more specifically, at least one nozzle 61) discharges the coolant L1 to the case 7 in such a way that the coolant L1 does not reach the cover 8. 【0023】 If coolant L1 remains in the refrigerant passage 91, products or parts manufactured by frictional stirring may fail inspection. Therefore, it is necessary to perform a cleaning step (hereinafter referred to as the "cleaning step") and a drying step for the refrigerant passage 91. 【0024】 In contrast, if the coolant L1 does not reach the cover 8 during frictional stirring, the coolant L1 will not enter the groove 73v (or the refrigerant flow path 91) through the gap between the case 7 and the cover 8. Therefore, the cleaning step of the refrigerant flow path 91 becomes unnecessary or the cleaning step is simplified. 【0025】 As illustrated in Figure 6, the case 7 may prevent the coolant L1 from reaching the cover 8. 【0026】 (Optional Additional Configurations) Next, with reference to Figures 1 to 29, optional additional configurations that can be adopted in the method for forming the refrigerant flow path in the first embodiment will be described. 【0027】 (Preparation process) In the first step ST1, the case 7 and the cover 8 that covers the groove 73v of the case 7 are prepared. The first step ST1 is a preparation process. 【0028】As illustrated in Figure 2, the case 7 prepared in the preparation step (first step ST1) has a side wall 71, an end wall 73, and a recess 74 defined by the side wall 71 and the end wall 73. As illustrated in Figure 1, the case 7 prepared in the preparation step (first step ST1) has a groove 73v formed on the outer surface 73t of the end wall 73. The groove 73v may be subdivided by at least one protrusion 73p. 【0029】 In the example shown in Figure 2, the side wall 71 and the end wall 73 are formed by integral molding. In the example shown in Figure 2, the case 7 has a box shape. In the example shown in Figure 2, the end wall 73 is a bottom wall 730 that defines the bottom of the recess 74. 【0030】 In the example shown in Figure 2, the side wall 71 includes a first side wall 71-1 and a second side wall 71-2. The second side wall 71-2 is positioned opposite the first side wall 71-1. 【0031】 The side wall 71 may include a first side wall 71-1, a second side wall 71-2, a third side wall 71-3, and a fourth side wall 71-4. In the example shown in Figure 2, the third side wall 71-3 connects the first side wall 71-1 and the second side wall 71-2. In the example shown in Figure 2, the fourth side wall 71-4 connects the first side wall 71-1 and the second side wall 71-2. The fourth side wall 71-4 is positioned opposite the third side wall 71-3. 【0032】 As illustrated in Figure 4, the end wall 73 of the case 7 may have a stepped portion 731 that is positioned opposite the outer edge 81 of the cover 8. 【0033】 The side wall 71 may have a projection (for example, a flange 72) held by a retaining member 50 (see Figure 6). The first side wall 71-1 may have a first protruding edge 72-1 held by a first retaining member 51a (see Figure 6). The second side wall 71-2 may have a second protruding edge 72-2 held by a second retaining member 51b (see Figure 6). In the example shown in Figure 2, each of the first protruding edge 72-1 and the second protruding edge 72-2 constitutes a part of the flange 72. 【0034】In the example shown in Figure 2, case 7 has a recess 74 capable of receiving an object to be cooled. The object to be cooled received in the recess 74 is, for example, an electrical device that generates heat when an electric current flows through it. Case 7 may also be an automotive part (for example, an electric vehicle part) that is mounted in an automobile with the electrical device housed inside. The electrical device that generates heat when an electric current flows through it is housed in the recess 74, for example, in contact with the end wall 73. 【0035】 The object to be cooled (more specifically, electrical equipment) received in the recess 74 is, for example, an inverter (more specifically, a device having a circuit that converts direct current to alternating current), a converter (more specifically, an AC-DC converter that converts alternating current to direct current, or a DC-DC converter that converts a direct current voltage to another direct current voltage), a battery, a charger for charging a battery, a control unit such as an engine control unit, or a circuit board on which multiple electronic components are arranged. 【0036】 The case 7 may have a mounting portion 75 to which a cover CB (see Figure 28) that covers the recess 74 can be attached. In the example shown in Figure 2, the mounting portion 75 has a hole 75h into which a bolt is inserted. The mounting portion 75 may be formed by casting. The outer shape of the mounting portion 75 may be formed by casting, and the hole 75h of the mounting portion 75 may be formed by machining (more specifically, drilling). 【0037】 The case 7 prepared in the preparation step (first step ST1) is, for example, a cast part. The side walls 71, end walls 73, and recesses 74 of the case 7 may be formed by casting. Alternatively, the side walls 71, end walls 73, and recesses 74 may be formed by cutting a block with a cutting tool. 【0038】 The groove 73v in the end wall 73 (see Figure 1) may be formed by casting. Alternatively, the groove 73v may be formed by cutting the end wall 73 with a cutting tool. 【0039】The case 7 prepared in the preparation step (first step ST1) may have a first port 79a connected to the groove 73v. Additionally, the case 7 prepared in the preparation step (first step ST1) may have a second port 79b connected to the groove 73v. One of the first port 79a and the second port 79b functions as an inlet port for supplying refrigerant to the refrigerant flow path 91, and the other of the first port 79a and the second port 79b functions as an outlet port for discharging refrigerant from the refrigerant flow path 91. Alternatively, as illustrated in Figure 7, the cover 8 may have a second port 89b connected to the groove 73v. Further alternatively, as illustrated in Figure 8, the cover 8 may have a first port 89a connected to the groove 73v and a second port 89b connected to the groove 73v. 【0040】 Alternatively, the first port may be formed by friction stir welding of the case 7 and the cover 8. In this case, the first port is formed by a part of the case 7 and a part of the cover 8. The second port 79b may be formed by friction stir welding of the case 7 and the cover 8. In this case, the second port is formed by a part of the case 7 and a part of the cover 8. 【0041】 If there is a possibility that coolant L1 may enter the groove 73v from the first port 79a, the first port 79a may be covered with a lid during friction stir welding. If there is a possibility that coolant L1 may enter the groove 73v from the second port 79b, the second port 79b may be covered with a lid during friction stir welding. 【0042】 Case 7 is, for example, made of metal. The main component of the material of Case 7 is, for example, aluminum. In other words, Case 7 is made of aluminum or an aluminum alloy. 【0043】As illustrated in FIG. 1, the cover 8 prepared in the preparation step (first step ST1) may have a flat plate shape. Alternatively, the cover 8 may have a concave or convex portion. As illustrated in FIG. 7, the cover 8 may have a second port 89b. As illustrated in FIG. 8, the cover 8 may have a first port 89a and a second port 89b. 【0044】 As illustrated in FIGS. 1 and 3, the method for forming the refrigerant flow path in the first embodiment includes a step of disposing the cover 8 on the case 7 so that the above-described groove portion 73v is covered by the cover 8. More specifically, the preparation step (first step ST1) includes disposing the cover 8 on the case 7 so that the above-described groove portion 73v is covered by the cover 8. 【0045】 The preparation step (first step ST1) may include disposing the cover 8 on the case 7 attached to the work support device 3 (see FIG. 6). Alternatively, the preparation step (first step ST1) may include attaching the case 7 to the work support device 3 after the cover 8 is disposed on the case 7. 【0046】 Attaching the case 7 to the work support device 3 may be performed manually or using a robot. Disposing the cover 8 on the case 7 may be performed manually or using a robot. 【0047】 As illustrated in FIG. 5, disposing the cover 8 on the case 7 may include disposing the outer edge portion 81 of the cover 8 to face the step portion 731 of the end wall 73. More specifically, by inserting the cover 8 into the recess 738 formed in the end wall 73 of the case 7, the outer edge portion 81 of the cover 8 may be disposed to face the step portion 731 of the end wall 73. 【0048】As illustrated in FIGS. 9 to 11, the preparation step (first step ST1) may include moving the detachment prevention member 67 from the retracted position P2 (see FIG. 9) away from the cover 8 to the advanced position P1 (see FIGS. 10 and 11) in contact with the cover 8 after the cover 8 is disposed on the case 7. When the detachment prevention member 67 contacts the cover 8, the cover 8 is prevented from coming off the case 7. 【0049】 In the example described in FIG. 11, the work support device 3 includes a jig 4 to which the case 7 is attached. In the example described in FIG. 11, the work support device 3 (more specifically, the jig 4) includes a backing member 40 that supports the case 7. 【0050】 As illustrated in FIG. 13, the backing member 40 receives a pressing force from the friction stir welding tool T1 via the case 7. In other words, when the case 7 is friction stir welded by the friction stir welding tool T1, the backing member 40 supports the case 7 against the pressing force received by the case 7 from the friction stir welding tool T1. 【0051】 In the example described in FIG. 13, the backing member 40 supports the end wall 73 of the case 7 (more specifically, the inner surface 73n of the end wall 73 of the case 7). 【0052】 As illustrated in FIG. 11, the backing member 40 may have a first support column 42-1 that supports the case 7 (more specifically, the end wall 73 of the case 7). As illustrated in FIG. 14, the first support column 42-1 may be telescopic so that the position of the tip of the first support column 42-1 can be adjusted. By adjusting the position of the tip of the first support column 42-1, the case 7 is suitably supported by the tip of the first support column 42-1. 【0053】 As illustrated in FIG. 11, the backing member 40 may have a second support column 42-2 that supports the case 7 (more specifically, the end wall 73 of the case 7). As illustrated in FIG. 15, the second support column 42-2 may be telescopic so that the position of the tip of the second support column 42-2 can be adjusted. By adjusting the position of the tip of the second support column 42-2, the case 7 is suitably supported by the tip of the second support column 42-2. 【0054】As illustrated in Figure 11, the length of the second support column 42-2 may differ from the length of the first support column 42-1. In this case, the multiple support columns 42, including the first support column 42-1 and the second support column 42-2, can suitably support a case 7 having a relatively complex shape. 【0055】 The jig 4 may include a base 64 that supports the backing member 40 (for example, a plurality of support columns 42 including a first support column 42-1 and a second support column 42-2). In the example shown in Figure 16, the base 64 is fixed to the table 31 of the work support device 3. 【0056】 As illustrated in Figure 16, the method for forming a refrigerant flow path in the first embodiment includes the step of attaching the case 7 to the workpiece support device 3 (more specifically, the jig 4). More specifically, the preparation step (first step ST1) includes attaching the case 7 to the workpiece support device 3 (more specifically, the jig 4). 【0057】 In the example shown in Figure 11, the workpiece support device 3 (more specifically, the jig 4) includes a holding member 50 for holding the case 7. In this case, the case 7 is attached to the workpiece support device 3 (more specifically, the jig 4) by attaching the case 7 to the holding member 50. 【0058】 In the example shown in Figure 11, the retaining member 50 holds the side wall 71 of the case 7. The retaining member 50 may include a first retaining member 51a that holds the first side wall 71-1 of the case 7 and a second retaining member 51b that holds the second side wall 71-2 of the case 7. 【0059】 The retaining member 50 may hold the flange portion 72 of the side wall 71 of the case 7. As illustrated in Figure 11, the first retaining member 51a may hold the first protruding edge portion 72-1 of the first side wall 71-1. The second retaining member 51b may hold the second protruding edge portion 72-2 of the second side wall 71-2. 【0060】As illustrated in Figures 9 and 10, the workpiece support device 3 (more specifically, the jig 4) may be equipped with the above-described detachment prevention member 67. The workpiece support device 3 (more specifically, the jig 4) may also be equipped with an actuator 68 that moves the above-described detachment prevention member 67 from the above-described retracted position P2 to the above-described extended position P1. 【0061】 In the examples shown in Figures 9 and 10, the detachment prevention member 67 includes a first detachment prevention member 67-1 and a second detachment prevention member 67-2. The workpiece support device 3 (more specifically, the jig 4) may include a first actuator 68-1 that moves the first detachment prevention member 67-1 between a first extended position P1-1 in contact with the cover 8 and a first retracted position P2-1 away from the cover 8. The workpiece support device 3 (more specifically, the jig 4) may also include a second actuator 68-2 that moves the second detachment prevention member 67-2 between a second extended position P1-2 in contact with the cover 8 and a second retracted position P2-2 away from the cover 8. 【0062】 (Joining process) In the second step ST2, the case 7 and the cover 8 are joined by friction stirring such that a refrigerant flow path 91 is formed by the groove 73v and the cover 8. The second step ST2 is a joining process. 【0063】 In the examples shown in Figures 12 and 13, the joining process (second step ST2) is performed with the case 7 supported by the workpiece support device 3 (more specifically, the backing member 40). More specifically, during the friction stir welding, the end wall 73 of the case 7 (more specifically, the inner surface 73n of the end wall 73) is supported by the backing member 40. By supporting the end wall 73 of the case 7 with the backing member 40, distortion of the end wall 73 caused by the end wall 73 being pressed by the friction stir welding tool T1 is suppressed. 【0064】In the example shown in Figure 13, the joining process (second step ST2) is performed with the case 7 held by the workpiece support device 3 (more specifically, the holding member 50). More specifically, during friction stirring, the side walls 71 of the case 7 are held by the holding member 50. By holding the case 7 by the holding member 50 during friction stirring, displacement of the case 7 is prevented. Furthermore, when the side walls 71 of the case 7 are held by the holding member 50, the friction stir joining tool T1, which moves relative to the holding member 50 during friction stirring, does not interfere with the holding member 50. 【0065】 The joining process (second step ST2) includes moving a rotating friction stir welding tool T1 relative to the case 7 and the cover 8 so that the case 7 and the cover 8 are joined by friction stir. 【0066】 In the example shown in Figure 13, the joining process (second step ST2) includes moving the rotating friction stir welding tool T1 relative to the case 7 and cover 8 while the friction stir welding tool T1 is pressing against the end walls 73 of the cover 8 and case 7. 【0067】 In the examples shown in Figures 17 to 20, the joining step (second step ST2) includes moving a rotating friction stir welding tool T1 relative to the case 7 and cover 8 along a first path PA (see Figure 21) so that the case 7 and cover 8 are joined by friction stir. 【0068】 In the example shown in Figure 19, the joining process (second step ST2) includes moving a rotating friction stir welding tool T1 relative to the case 7 and cover 8 along the boundary PA1 between the case 7 and cover 8. In other words, the first path PA described above includes the boundary PA1 between the case 7 and cover 8. In this case, the case 7 and cover 8 are butt-joined by friction stir welding. Also, the boundary PA1 between the case 7 and cover 8 is flattened. 【0069】In the example shown in Figure 13, the joining process (second step ST2) includes butt joining the stepped portion 731 of the end wall 73 (see Figure 5) and the outer edge portion 81 of the cover 8 (see Figure 5) by friction stir. In other words, the first path PA described above includes the boundary between the stepped portion 731 of the case 7 and the outer edge portion 81 of the cover 8. 【0070】 In the example shown in Figure 13, when the case 7 is inverted, the case 7 is supported by the workpiece support device 3 (more specifically, the backing member 40). Some of the multiple support columns 42 may support the end wall 73 of the case 7 in the vicinity of the side wall 71. 【0071】 As can be seen from Figures 1 and 21, the first path PA may include a path PA2 along the region where the case 7 and the cover 8 are overlapped. In the example shown in Figure 21, the first path PA includes a path PA2-1 passing through the central portion 83 of the cover 8. In this case, as illustrated in Figure 22, the joining step (second step ST2) includes moving the rotating friction stir welding tool T1 relative to the cover 8 along the surface of the cover 8 while the friction stir welding tool T1 is pressing the central portion 83 of the cover 8 toward the end wall 73 of the case 7. In this way, the case 7 and the central portion 83 of the cover 8 are joined together by friction stir. 【0072】 When the case 7 and the central portion 83 of the cover 8 are joined together by overlapping, the outward distortion of the central portion 83 of the cover 8 due to the pressure of the refrigerant flowing through the refrigerant passage 91 when the refrigerant passage 91 is in use is suppressed. 【0073】 In the example shown in Figure 22, at least one of the multiple support columns 42 is located vertically below the central portion 83 of the cover 8. More specifically, when the case 7 and the central portion 83 of the cover 8 are joined together, at least one of the multiple support columns 42 supports the end wall 73 of the case 7 vertically below the friction stir welding tool T1. 【0074】In the example shown in Figure 21, the first path PA includes both the boundary PA1 between the case 7 and the cover 8, and the path PA2-1 passing through the central portion 83 of the cover 8. In this case, the case 7 and the cover 8 are butt-joined by friction stir, and the central portion 83 of the case 7 and the cover 8 are overlap-joined by friction stir. 【0075】 As illustrated in Figure 13, friction stir is performed with the case 7 and cover 8 pressed in a first direction DR1 by the friction stir welding tool T1. The workpiece support device 3 (more specifically, the backing member 40) supports the case 7 against the pressing force that the case 7 and cover 8 receive from the friction stir welding tool T1. 【0076】 In the example shown in Figure 11, the first direction DR1 coincides with the direction from the end wall 73 of case 7 toward the internal space SP of the recess 74 of case 7. In the example shown in Figure 11, the end wall 73 is a wall located at the end of the side wall 71 on the second direction DR2 side. In the example shown in Figure 11, the end wall 73 is connected to the end of the first side wall 71-1 on the second direction DR2 side, and also connected to the end of the second side wall 71-2 on the second direction DR2 side. 【0077】 As illustrated in Figure 17, the friction stirring described above may be started when the anti-detachment member 67 is in the extended position P1, which is in contact with the cover 8. In this case, the cover 8 is prevented from detaching from the case 7 when the friction stirring is started. 【0078】 The joining process (second step ST2) may include moving the anti-detachment member 67 (e.g., first anti-detachment member 67-1) from the aforementioned advanced position P1 to the aforementioned retracted position P2 in response to the friction stir welding tool T1 approaching the anti-detachment member 67 (e.g., first anti-detachment member 67-1). The joining process (second step ST2) may also include moving the anti-detachment member 67 (e.g., first anti-detachment member 67-1) from the aforementioned retracted position P2 to the aforementioned advanced position P1 in response to the friction stir welding tool T1 moving away from the aforementioned advanced position P1. 【0079】More specifically, as illustrated in Figures 17 and 18, the joining step (second step ST2) may include retracting the first retaining member 67-1 from a first extended position P1-1 to a first retracted position P2-1 so that the first retaining member 67-1 moves away from the cover 8 as the friction stir welding tool T1 approaches the first retaining member 67-1. As illustrated in Figures 18 and 19, the joining step (second step ST2) may also include returning the first retaining member 67-1 from the first retracted position P2-1 to the first extended position P1-1 as the friction stir welding tool T1 moves away from the first extended position P1-1. 【0080】 As illustrated in Figures 17 and 18, the joining process (second step ST2) may include retracting the first retaining member 67-1 so that it moves away from the cover 8 while the second retaining member 67-2 is maintained in the aforementioned second extended position P1-2, in response to the friction stir welding tool T1 approaching the first retaining member 67-1. Alternatively, as illustrated in Figures 19 and 20, the joining process (second step ST2) may also include retracting the second retaining member 67-2 so that it moves away from the cover 8 while the first retaining member 67-1 is maintained in the aforementioned first extended position P1-1, in response to the friction stir welding tool T1 approaching the second retaining member 67-2. 【0081】 (Coolant discharge process) In the third step ST3, coolant L1 is discharged into case 7. The third step ST3 is the coolant discharge process. The coolant discharge process (third step ST3) is performed while friction stirring is in progress. In other words, the coolant discharge process (third step ST3) is performed while the joining process (second step ST2) is in progress. 【0082】 The coolant discharge process (third step ST3) may be started before the start of the joining process (second step ST2). Alternatively, the coolant discharge process (third step ST3) may be started simultaneously with the joining process (second step ST2). The coolant discharge process (third step ST3) may be started manually or based on a command from the control device. 【0083】 The coolant discharge process (third step ST3) may be stopped after the completion of the joining process (second step ST2). Alternatively, the coolant discharge process (third step ST3) may be stopped simultaneously with the completion of the joining process (second step ST2). The coolant discharge process (third step ST3) may be stopped by manual operation or based on a command from the control device. 【0084】 During frictional stirring, the release of the coolant L1 into case 7 suppresses distortion of case 7 caused by the heat generated by frictional stirring. 【0085】 In the example shown in Figure 13, during friction stirring, the coolant L1 is applied to the inner surface 7n of case 7 (more specifically, the inner surface 7n of case 7 defining the recess 74). More specifically, during friction stirring, the applicator 60 (more specifically, at least one nozzle 61) discharges the coolant L1 onto the inner surface 7n of case 7. 【0086】 The inner surface 7n of case 7 and the cover 8 that covers the groove 73v are separated by the side wall 71 and the end wall 73 of case 7. Therefore, the coolant L1 released toward the inner surface 7n of case 7 does not reach the cover 8. Consequently, the coolant L1 released toward the inner surface 7n of case 7 does not enter the groove 73v (or the refrigerant flow path 91) through the gap between case 7 and cover 8. 【0087】 In the example shown in Figure 13, the coolant L1 is applied to the inner surface 73n of the end wall 73 during frictional stirring. By applying the coolant L1 to the inner surface 73n of the end wall 73, deformation of the end wall 73 due to the heat generated by frictional stirring is suppressed. 【0088】When the coolant L1 is applied to the inner surface 73n of the end wall 73 (more specifically, when the coolant L1 is sprayed onto the inner surface 73n of the end wall 73), the side wall 71 prevents the coolant L1 from reaching the cover 8. More specifically, the side wall 71 prevents the coolant L1 from flowing around towards the cover 8. As a result, the coolant L1 applied to the inner surface 73n of the end wall 73 does not enter the groove 73v (or the coolant flow path 91) through the gap between the case 7 and the cover 8. 【0089】 In the example shown in Figure 13, during friction stirring, the end wall 73 is supported by the backing member 40, and the coolant L1 is applied to the inner surface 73n of the end wall 73. In this case, distortion of the end wall 73 due to friction stirring is suppressed by both the backing member 40 and the coolant L1. 【0090】 In the example shown in Figure 13, during friction stirring, coolant L1 is discharged from at least one nozzle 61 toward the inner surface 7n of the case 7 (more specifically, the inner surface 73n of the end wall 73). During friction stirring, at least one nozzle 61 may spray coolant L1 toward the inner surface 7n of the case 7 (more specifically, the inner surface 73n of the end wall 73). At least one nozzle 61 may be attached to a backing member 40 (e.g., a first support 42-1) that supports the end wall 73. As illustrated in Figure 23, a plurality of nozzles 61 that discharge coolant onto the inner surface 7n of the case 7 may be attached to a backing member 40 (e.g., a first support 42-1) that supports the end wall 73. 【0091】 As illustrated in Figure 24, at least one nozzle 61 (more specifically, a plurality of nozzles 61) included in the applicator 60 may discharge the coolant L1 over substantially the entire inner surface 73n of the end wall 73, excluding the portion of the inner surface 73n of the end wall 73 that is in contact with the backing member 40. 【0092】When the coolant L1 reaches substantially the entire inner surface 73n of the end wall 73, excluding the portion in contact with the backing member 40, distortion of the end wall 73 due to heat generated by friction stirring is suppressed, regardless of the position where it is frictionally stirred by the friction stir welding tool T1. Therefore, it is not necessary to move at least one nozzle 61 in response to a change in the position where it is frictionally stirred by the friction stir welding tool T1. 【0093】 Alternatively, or additionally, as illustrated in Figure 24, coolant L1 may be discharged from at least one nozzle 61 onto the inner surface 71n of the side wall 71 during friction stirring. 【0094】 In the example shown in Figure 13, the coolant L1 is applied to the outer surface 71t of the side wall 71 during friction stirring. More specifically, during friction stirring, the applicator 60 discharges the coolant L1 onto the outer surface 71t of the side wall 71. 【0095】 The coolant L1 applied to the outer surface 71t of the side wall 71 cools the side wall 71. In addition, the end wall 73 is indirectly cooled as the side wall 71 is cooled. Therefore, deformation of the end wall 73 (especially the outer edge of the end wall 73) due to heat generated by frictional stirring is suppressed. 【0096】 The outer surface 71t of the side wall 71 of case 7 and the cover 8 covering the groove 73v are spaced apart. Therefore, the coolant L1 applied to the outer surface 71t of the side wall 71 of case 7 does not reach the cover 8. In the example shown in Figure 13, the coolant L1 released toward the outer surface 71t of the side wall 71 of case 7 does not enter the groove 73v (or the coolant flow path 91) through the gap between case 7 and cover 8. 【0097】 In the example shown in Figure 13, during friction stirring, coolant L1 is discharged from at least one nozzle 62 onto the outer surface 71t of the side wall 71. In this specification, to distinguish between the nozzle 61 that discharges coolant L1 onto the inner surface 7n of the case 7 and the nozzle 62 that discharges coolant L1 onto the outer surface 71t of the side wall 71 of the case 7, the latter is referred to as the "outer nozzle 62". 【0098】In the example shown in Figure 13, at least one outer nozzle 62 is supported by a workpiece support device 3 (more specifically, a jig 4). 【0099】 As illustrated in Figure 13, during friction stirring, the coolant L1 may be applied to both the inner surface 7n of the case 7 (more specifically, the inner surface 73n of the end wall 73) and the outer surface 71t of the side wall 71 of the case 7. Alternatively, as illustrated in Figure 24, during friction stirring, the coolant L1 may be applied only to the inner surface 7n of the case 7. Further alternatively, during friction stirring, the coolant L1 may be applied only to the outer surface 71t of the side wall 71 of the case 7. 【0100】 The coolant L1 is, for example, a water-soluble coolant. The main component of the water-soluble coolant is, for example, water. The water-soluble coolant may also contain a water-soluble lubricant (for example, a water-soluble cutting fluid or a water-soluble grinding fluid) and / or a surfactant. 【0101】 The coolant L1 may be a liquid with the same components as the cutting fluid applied to the workpiece (for example, the case 7 or other workpiece) when the workpiece is being machined. 【0102】 (Cutting process) The method for forming the refrigerant flow path in the first embodiment may include a step of cutting at least one of the case 7 and the cover 8 with a cutting tool T2 (hereinafter referred to as the "cutting process"). In other words, in the fourth step ST4, at least one of the case 7 and the cover 8 may be cut with the cutting tool T2. 【0103】In the examples shown in Figures 25 and 26, the cutting process (fourth step ST4) is performed after the joining process (in other words, after the friction stir welding of the case 7 and the cover 8 is completed). In this case, after the joining process (second step ST2) and before the cutting process (fourth step ST4), the friction stir welding tool T1 held on the spindle 151 described later may be replaced with a cutting tool T2. The replacement of the friction stir welding tool T1 held on the spindle 151 with the cutting tool T2 may be performed by a tool changer 19 or manually. 【0104】 In the example shown in Figure 26, the cutting process (fourth step ST4) includes cutting a portion of the joint area JR between the end wall 73 of the case 7 and the cover 8. 【0105】 The cutting process (fourth step ST4) may include removing burrs generated during friction stirring using a cutting tool T2 (e.g., a milling tool T2-1). 【0106】 Alternatively, or additionally, the cutting step (fourth step ST4) may include forming a hole (for example, the hole 75h of the mounting portion 75 shown in Figure 2) in the case 7 and / or cover 8 using a cutting tool T2 (for example, a drilling tool T2-2). Alternatively, or additionally, the cutting step (fourth step ST4) may include forming a screw thread in the aforementioned hole (for example, the hole formed in the case 7) using a cutting tool T2 (for example, a tapping tool). 【0107】 In the example shown in Figure 25, the cutting step (fourth step ST4) includes moving a rotating cutting tool T2 relative to the case 7 and cover 8 along the second path PB so that at least one of the case 7 and cover 8 is cut by the cutting tool T2. 【0108】The second path PB may overlap with the first path PA described above. For example, a rotating cutting tool T2 (e.g., a milling tool T2-1) may move relative to the case 7 and cover 8 along the second path PB which overlaps with the first path PA described above. In this case, burrs generated during friction stirring are removed by the cutting tool T2 (e.g., a milling tool T2-1). 【0109】 The second path PB may include a path parallel to the first direction DR1. For example, a rotating cutting tool T2 (e.g., a drilling tool T2-2) may move along the second path PB, thereby forming a hole in the case 7 and / or cover 8. Alternatively, or additionally, a rotating cutting tool T2 (e.g., a tapping tool) may move along the second path PB, thereby forming a screw thread in the aforementioned hole (e.g., a hole formed in the case 7). 【0110】 In the example shown in Figure 26, the cutting process (fourth step ST4) is performed after the joining process (second step ST2). Alternatively, or additionally, the cutting process (fourth step ST4) may be performed before the joining process (second step ST2). Further alternatively, the cutting process (fourth step ST4) may be omitted. 【0111】 (Method for manufacturing a structure EB having a refrigerant flow path) The method for manufacturing a structure EB having a refrigerant flow path in the first embodiment includes, in addition to the first step ST1 to the third step ST3 described above (or, in addition to the first step ST1 to the fourth step ST4 described above), (1) a step of placing the object to be cooled OB in the recess 74 of the case 7 (see Figure 27), and (2) a step of fixing the lid CB to the case 7 so that the recess 74 of the case 7 is closed by the lid CB (see Figure 28). 【0112】Placing the object to be cooled OB in the recess 74 of case 7 is performed after the friction stir welding of case 7 and cover 8 is completed. Placing the object to be cooled OB in the recess 74 of case 7 may also be performed after the cutting process (fourth step ST4). Since the object to be cooled has already been described, a repeated explanation of the object to be cooled will be omitted. 【0113】 The step of fixing the lid CB to case 7 is performed after the step of placing the object to be cooled OB in the recess 74 of case 7. The lid CB may be fixed to case 7 by inserting bolts into the holes 75h (see Figure 27). Alternatively, the lid CB may be fixed to case 7 by friction stir welding. 【0114】 (Machine Tool 1) The machine tool 1 in the first embodiment will be described with reference to Figures 1 to 36. Figure 30 is a schematic front view showing a part of the machine tool 1 in the first embodiment. Figure 31 is a schematic perspective view showing an example of a jig 4 that supports the case 7 and cover 8. Figure 32 is a diagram for explaining an example of a spray nozzle SN. Figures 33 and 34 are schematic perspective views showing the machine tool 1 in the first embodiment. Figure 35 is a schematic front view showing a part of the machine tool 1 in the first embodiment. Figure 36 is a diagram that schematically shows how the control device 2 can control a plurality of controlled devices. 【0115】 As illustrated in Figure 30, the machine tool 1 comprises a workpiece support device 3, a spindle 151, a support body 153, a rotary drive device 16, a moving device 17, a feeding device 12, and an applicator 60. 【0116】 As illustrated in Figure 30, the workpiece support device 3 supports the case 7 and the cover 8. As illustrated in Figure 11, the case 7 has a recess 74 defined by the side wall 71 and the end wall 73, and a groove 73v formed on the outer surface 73t of the end wall 73. The cover 8 covers the groove 73v of the case 7. Since the case 7 and the cover 8 have already been described, a repetitive description of the case 7 and the cover 8 will be omitted. 【0117】As illustrated in Figure 30, the spindle 151 is capable of holding the friction stir welding tool T1. The friction stir welding tool T1 joins the case 7 and the cover 8 by friction stir such that a coolant flow path 91 is formed by the groove 73v and the cover 8. 【0118】 The support 153 supports the spindle 151 so that it can rotate around the first axis AX1. The rotary drive device 16 rotates the spindle 151 around the first axis AX1. The rotary drive device 16 may include a motor 16m that rotates the spindle 151 around the first axis AX1. 【0119】 In the example shown in Figure 30, the machine tool 1 is equipped with a machining head 15, which includes the spindle 151 and the support 153 described above. The machining head 15 may also be equipped with the motor 16m described above. 【0120】 The moving device 17 moves the machining head 15 (more specifically, the spindle 151 and support 153) relative to the workpiece support device 3. The moving device 17 may include a machining head moving device 171 for moving the machining head 15. Alternatively or additionally, the moving device 17 may include a table moving device 178 for moving the table 31 of the workpiece support device 3. 【0121】 The supply device 12 supplies the coolant L1 to the applicator 60. The applicator 60 discharges the coolant L1 into the case 7 during friction agitation. As illustrated in Figure 12, the applicator 60 may include at least one nozzle 61 that discharges the coolant L1 onto the inner surface 7n of the case 7. The coolant L1 discharged onto the inner surface 7n of the case 7 does not reach the cover 8. Therefore, the coolant L1 discharged onto the inner surface 7n of the case 7 does not enter the groove 73v (or the refrigerant flow path 91) through the gap between the case 7 and the cover 8. 【0122】As illustrated in Figure 12, the applicator 60 may include a first nozzle 61a for discharging coolant L1 onto the inner surface 73n of the end wall 73 of the case 7. Alternatively, or additionally, as illustrated in Figure 24, the applicator 60 may include a second nozzle 61b for discharging coolant L1 onto the inner surface 73n of the end wall 73 of the case 7 and / or the inner surface 71n of the side wall 71 of the case 7. 【0123】 Alternatively, or additionally, the applicator 60 may include at least one outer nozzle 62 for discharging coolant L1 onto the outer surface 71t of the side wall 71 of the case 7. 【0124】 The machine tool 1 in the first embodiment includes an applicator 60 that discharges a coolant L1 into the case 7. The applicator 60 discharges the coolant L1 into the case 7 when the case 7 and the cover 8 are friction stir welded. In this way, distortion of the case 7 due to heat generated by friction stir is suppressed. 【0125】 In the examples shown in Figures 12 and 24, the applicator 60 discharges the coolant L1 only to the case 7 of the case 7 and cover 8. More specifically, during frictional stirring, the applicator 60 discharges the coolant L1 to the case 7 in such a way that the coolant L1 does not reach the cover 8. 【0126】 If the coolant L1 does not reach the cover 8 during frictional stirring, the coolant L1 will not enter the groove 73v (or the refrigerant flow path 91) through the gap between the case 7 and the cover 8. Therefore, the cleaning step of the refrigerant flow path 91 becomes unnecessary or is simplified. 【0127】 In the examples shown in Figures 12 and 24, when the case 7 and cover 8 are supported by the workpiece support device 3 (more specifically, the jig 4), the applicator 60 is positioned opposite the case 7, not opposite the cover 8. In this case, the coolant L1 released from the applicator 60 is less likely to enter the groove 73v (or the coolant flow path 91) through the gap between the case 7 and the cover 8. 【0128】(Optional Additional Configurations) Next, with reference to Figures 1 to 36, optional additional configurations that can be adopted in the machine tool 1 in the first embodiment will be described. 【0129】 (Work support device 3) In the example shown in Figure 16, the machine tool 1 includes a work support device 3. The work support device 3 includes a jig 4 to which the case 7 is attached. The work support device 3 may also include a table 31 to which the jig 4 is attached. 【0130】 In the example shown in Figure 16, the machine tool 1 (more specifically, the moving device 17) includes a machining head moving device 171 for moving the machining head 15. In the example shown in Figure 16, the machining head moving device 171 can move the machining head 15 in a direction substantially parallel to the vertical direction (Z direction). The machining head moving device 171 may also move the machining head 15 in a direction substantially parallel to the horizontal plane. 【0131】 In the example shown in Figure 16, the machine tool 1 (more specifically, the moving device 17) includes a table moving device 178 for moving the table 31. The table moving device 178 can move the table 31 in a direction substantially parallel to the horizontal plane. In the example shown in Figure 16, the table moving device 178 includes an X-axis moving device 178a for moving the table 31 in a direction along the X-axis substantially parallel to the horizontal plane. The table moving device 178 may also include a Y-axis moving device 178b for moving the table 31 in a direction along the Y-axis perpendicular to both the vertical and the X-axis. 【0132】 In the example shown in Figure 11, the workpiece support device 3 (more specifically, the jig 4) includes a backing member 40 that supports the end wall 73 of the case 7. The backing member 40 receives pressing force from the friction stir welding tool T1 via the case 7 and cover 8, and supports the end wall 73 of the case 7. 【0133】 The backing member 40 suppresses the distortion of the end wall 73 caused by the end wall 73 being pressed by the friction stir welding tool T1. 【0134】In the example shown in Figure 11, the backing member 40 has a first support column 42-1 that supports the case 7. The backing member 40 may have a plurality of support columns 42, including the first support column 42-1 and the second support column 42-2. Each of the plurality of support columns 42 receives pressing force from the friction stir welding tool T1 via the case 7 and cover 8. In other words, when the case 7 and cover 8 are frictionally stirred by the friction stir welding tool T1, each of the plurality of support columns 42 supports the case 7 against the pressing force that the case 7 and cover 8 receive from the friction stir welding tool T1. 【0135】 In the example shown in Figure 11, the first support column 42-1 has a first end 42a-1 that contacts the inner surface 73n of the end wall 73 of the case 7. In the example shown in Figure 11, the second support column 42-2 has a second end 42a-2 that contacts the inner surface 73n of the end wall 73 of the case 7. 【0136】 In the example shown in Figure 11, the position of the first end 42a-1 is different from the position of the second end 42a-2 in the direction along the first direction DR1. More specifically, the second end 42a-2 is located closer to the first direction DR1 (more specifically, lower) than the first end 42a-1. 【0137】 In the example shown in Figure 13, a first supply channel 44 for supplying coolant L1 to the first nozzle 61a is formed inside the backing member 40 (more specifically, inside the first support column 42-1). 【0138】 In the example shown in Figure 11, the jig 4 includes a base 64 that supports the backing member 40. In the example shown in Figure 11, the base 64 supports a plurality of support columns 42, including a first support column 42-1 and a second support column 42-2. The base 64 can be attached to the table 31 of the workpiece support device 3. The base 64 is also removable from the table 31. 【0139】 In the example shown in Figure 14, the relative position of the first end 42a-1 of the first support column 42-1 with respect to the base 64 can be adjusted in the first direction DR1 (and the second direction DR2). In the example shown in Figure 15, the relative position of the second end 42a-2 of the second support column 42-2 with respect to the base 64 can be adjusted in the first direction DR1 (and the second direction DR2). 【0140】 As illustrated in Figure 14, the first support column 42-1 may be extendable or retractable. More specifically, the first support column 42-1 may include a first portion 421-1 fixed to the base 64 and a second portion 421-2 that is relatively movable relative to the first portion 421-1 in a second direction DR2 (for example, upward). In the example shown in Figure 14, the first end 42a-1 described above is located on the second portion 421-2. The first nozzle 61a described above is also located on the second portion 421-2. 【0141】 When the first support column 42-1 extends, the position of the first end 42a-1 of the first support column 42-1 is adjusted to move away from the base 64 (in other words, in the second direction DR2). When the first support column 42-1 retracts, the position of the first end 42a-1 of the first support column 42-1 is adjusted to move closer to the base 64 (in other words, in the first direction DR1). 【0142】 The first support column 42-1 may include a first spring 64-1 that biases the second portion 421-2 in a second direction DR2 (e.g., upward). Alternatively, or additionally, the first support column 42-1 may include a fluid pressure cylinder (e.g., an air cylinder or a hydraulic cylinder) that moves the second portion 421-2 in the second direction DR2 (e.g., upward). 【0143】 In the example shown in Figure 14, when the second portion 421-2 is pressed by the case 7, the first spring 64-1 compresses. As a result, the height of the second portion 421-2 is automatically adjusted to correspond to the shape of the case 7 or to manufacturing tolerances of the case 7. 【0144】 As illustrated in Figure 11, the first support column 42-1 may include a first fixing member 65-1 for fixing the relative position of the second portion 421-2 with respect to the first portion 421-1. In this case, after the height of the second portion 421-2 has been adjusted, the height of the second portion 421-2 can be fixed using the first fixing member 65-1. 【0145】As illustrated in Figure 15, the second support column 42-2 may be extendable or retractable. More specifically, the second support column 42-2 may include a third portion 421-3 fixed to the base 64 and a fourth portion 421-4 that is relatively movable relative to the third portion 421-3 in a second direction DR2 (e.g., upward). In the example shown in Figure 15, the second end 42a-2 described above is located on the fourth portion 421-4. 【0146】 When the second support column 42-2 extends, the position of the second end 42a-2 of the second support column 42-2 is adjusted to move away from the base 64 (in other words, in the second direction DR2). When the second support column 42-2 retracts, the position of the second end 42a-2 of the second support column 42-2 is adjusted to move closer to the base 64 (in other words, in the first direction DR1). 【0147】 The second support column 42-2 may include a second spring 64-2 that biases the fourth portion 421-4 in a second direction DR2 (e.g., upward). Alternatively, or additionally, the second support column 42-2 may include a fluid pressure cylinder (e.g., an air cylinder or a hydraulic cylinder) that moves the fourth portion 421-4 in the second direction DR2 (e.g., upward). 【0148】 As illustrated in Figure 11, the second support column 42-2 may include a second fixing member 65-2 for fixing the relative position of the fourth portion 421-4 with respect to the third portion 421-3. In this case, after the height of the fourth portion 421-4 has been adjusted, the height of the fourth portion 421-4 can be fixed using the second fixing member 65-2. 【0149】 In the example shown in Figure 31, the base 64 includes a lower base 641 and an upper base 646. The base 64 also includes a plurality of connecting columns 647 that connect the lower base 641 and the upper base 646. In the example shown in Figure 31, the lower base 641 is positioned on the first direction DR1 side of the upper base 646. 【0150】In the example shown in Figure 31, the lower base 641 supports the backing member 40. In the example shown in Figure 31, the retaining member 50 is positioned on the upper base 646. As illustrated in Figure 31, the outer nozzle 62 may be supported on the base 64 (more specifically, the upper base 646). 【0151】 In the example shown in Figure 16, the base 64 (more specifically, the lower base 641) is attached to the table 31. In the example shown in Figure 16, the machine tool 1 includes a fixing member F for fixing the base 64 (more specifically, the lower base 641) to the table 31. The fixing member F is, for example, a bolt F1. 【0152】 In the example shown in Figure 11, the workpiece support device 3 (more specifically, the jig 4) includes a holding member 50 that holds the side wall 71 of the case 7. In the example shown in Figure 11, the end wall 73 of the case 7 and the cover 8 can be friction stir-welded while the side wall 71 of the case 7 is held by the holding member 50. 【0153】 The holding member 50 prevents the case 7 from shifting position during friction stirring. Furthermore, when the side wall 71 of the case 7 is held by the holding member 50, the friction stir welding tool T1, which moves relative to the holding member 50 during friction stirring, does not interfere with the holding member 50. 【0154】 In the example shown in Figure 11, the retaining member 50 includes a first retaining member 51a that holds the first side wall 71-1 of the case 7, and a second retaining member 51b that holds the second side wall 71-2 of the case 7. 【0155】 In the example shown in Figure 11, the backing member 40 is positioned to cross the space SP1 between the first retaining member 51a and the second retaining member 51b. 【0156】In the example shown in Figure 11, the first retaining member 51a has a first movable portion 513a that is repositionable relative to the first fixed portion 511a (for example, a portion of the upper base 646). As the first movable portion 513a moves toward the first fixed portion 511a, the first side wall 71-1 of the case 7 is clamped between the first fixed portion 511a and the first movable portion 513a. The first movable portion 513a may be screwed onto a first threaded member SB1. In this case, the first movable portion 513a moves toward the first fixed portion 511a as the first threaded member SB1 rotates relative to the first movable portion 513a. Alternatively, the first retaining member 51a may include a fluid pressure cylinder (for example, an air cylinder or a hydraulic cylinder) that moves the first movable portion 513a toward the first fixed portion 511a. 【0157】 In the example shown in Figure 11, the second retaining member 51b has a second movable portion 513b that is repositionable relative to the second fixed portion 511b (for example, another portion of the upper base 646). As the second movable portion 513b moves toward the second fixed portion 511b, the second side wall 71-2 of the case 7 is clamped between the second fixed portion 511b and the second movable portion 513b. The second movable portion 513b may be screwed onto a second threaded member SB2. In this case, the second movable portion 513b moves toward the second fixed portion 511b as the second threaded member SB2 rotates relative to the second movable portion 513b. Alternatively, the second retaining member 51b may include a fluid pressure cylinder (for example, an air cylinder or a hydraulic cylinder) that moves the second movable portion 513b toward the second fixed portion 511b. 【0158】 In the example shown in Figure 23, the retaining members 50 (for example, the first retaining member 51a and the second retaining member 51b) are supported by the base 64 (more specifically, the upper base 646). 【0159】In the examples shown in Figures 9 and 10, the workpiece support device 3 (more specifically, the jig 4) includes a detachment prevention member 67 that prevents the cover 8 from coming off the case 7. In the examples shown in Figures 9 and 10, the detachment prevention member 67 includes a first detachment prevention member 67-1 and a second detachment prevention member 67-2. The workpiece support device 3 (more specifically, the jig 4) may also include a first actuator 68-1 that moves the first detachment prevention member 67-1 between a first extended position P1-1 in contact with the cover 8 and a first retracted position P2-1 away from the cover 8. The workpiece support device 3 (more specifically, the jig 4) may also include a second actuator 68-2 that moves the second detachment prevention member 67-2 between a second extended position P1-2 in contact with the cover 8 and a second retracted position P2-2 away from the cover 8. 【0160】 In the examples shown in Figures 9 and 10, the anti-detachment members 67 (for example, the first anti-detachment member 67-1 and the second anti-detachment member 67-2) are supported by the base 64 (more specifically, the upper base 646). 【0161】 In the example shown in Figure 12, at least one nozzle 61 is attached to the jig 4 (more specifically, the backing member 40 of the jig 4). In the example shown in Figure 12, the first nozzle 61a is attached to the side surface 43 of the backing member 40 (more specifically, the side surface 43 of the first support column 42-1). 【0162】 In the example shown in Figure 12, at least one nozzle 61 (e.g., a first nozzle 61a) is a spray nozzle SN that diffuses the coolant L1 toward the inner surface 7n of the case 7. As illustrated in Figure 32, the spray nozzle SN (e.g., a first nozzle 61a) may be configured to diffuse the coolant L1 in a fan shape. Alternatively, the spray nozzle SN (e.g., a first nozzle 61a) may be configured to diffuse the coolant L1 in a conical shape. 【0163】 In the example shown in Figure 12, at least one outer nozzle 62 is attached to the jig 4 (more specifically, the base 64 of the jig 4). 【0164】Each of the multiple outer nozzles 62 may discharge the coolant L1 in a fan shape toward the outer surface 71t of the side wall 71 so that the side wall 71 is cooled over a wide area. 【0165】 From the viewpoint of preventing the coolant L1 from reaching the cover 8, each of the multiple outer nozzles 62 may discharge the coolant L1 diagonally downward. From the viewpoint of preventing the coolant L1 from reaching the cover 8, the discharge speed of the coolant L1 from each of the multiple outer nozzles 62 may be slower than the discharge speed of the coolant L1 from the first nozzle 61a. If the discharge speed of the coolant L1 from the outer nozzles 62 is slow, the coolant L1 discharged from the outer nozzles 62 is less likely to diffuse upward. 【0166】 The machine tool 1 may be capable of selectively executing a first discharge mode (see Figure 24) in which the discharge of coolant L1 from the first nozzle 61a is stopped, and a second discharge mode (see Figure 12) in which the coolant L1 is discharged from both the first nozzle 61a and the outer nozzle 62. 【0167】 (Wall 11a and door 11b) As illustrated in Figures 33 and 34, the machine tool 1 may be provided with a wall 11a surrounding the machining area RG1 where friction stirring is performed. The wall 11a prevents the coolant L1 from splashing outside the machining area RG1 where friction stirring is performed. 【0168】 The wall 11a surrounds the case 7 and cover 8, which are supported by the workpiece support device 3. In the examples shown in Figures 33 and 34, the wall 11a surrounds the jig 4 that supports the case 7 and cover 8. The wall 11a also surrounds the lower end portion 15g of the machining head 15. In the examples shown in Figures 33 and 34, the wall 11a surrounds the table 31. 【0169】 As illustrated in Figures 33 and 34, the wall 11a may have an opening OP through which the case 7 and cover 8 can pass. In the example shown in Figures 33 and 34, the machine tool 1 includes a door 11b that opens and closes the opening OP formed in the wall 11a. The wall 11a and the door 11b surround the machining area RG1 where friction stirring is performed, preventing the coolant L1 from splashing outside the machining area RG1. 【0170】 (Supply device 12) In the example shown in Figure 30, the supply device 12 includes a pump 121 that supplies the coolant L1 to the applicator 60 (for example, at least one nozzle 61). The supply device 12 may also include a valve 123 positioned between the applicator 60 (for example, at least one nozzle 61) and the pump 121. 【0171】 (Circulation of coolant L1) As illustrated in Figure 30, the machine tool 1 may include a circulation channel 13 for circulating the coolant L1 and a tank 141 for storing the coolant L1. 【0172】 The circulation channel 13 includes a supply channel 131 that supplies coolant L1 from the tank 141 to the applicator 60 (for example, at least one nozzle 61). 【0173】 The circulation channel 13 includes a return channel 138 that returns the coolant L1 in the processing area RG1 where the friction agitation described above takes place back to the tank 141. When the processing area RG1 is surrounded by a wall 11a, the coolant L1 can be recovered smoothly. 【0174】 (Chiller 143) The machine tool 1 may be equipped with a chiller 143 for lowering the temperature of the coolant L1. In the example shown in Figure 30, the chiller 143 receives the coolant L1 from the tank 141 and lowers the temperature of the received coolant L1. The cooled coolant L1 is returned to the tank 141. 【0175】 (Cutting tool T2) As illustrated in Figure 25, the machine tool 1 may be capable of cutting at least one of the case 7 and the cover 8 using a cutting tool T2. More specifically, the spindle 151 may be capable of holding the cutting tool T2. 【0176】 For example, if burrs are generated from at least one of the case 7 and cover 8 by the friction stir welding tool T1, these burrs may be removed using a cutting tool T2 (e.g., a milling tool T2-1). 【0177】The cutting tool T2 attached to the spindle 151 may be a drilling tool T2-2. After the case 7 and cover 8 are friction stir-welded, holes may be formed in the case 7 and / or cover 8 using the cutting tool T2 (for example, the drilling tool T2-2). For example, the hole 75h of the mounting portion 75 (see Figure 2) may be formed using the drilling tool T2-2. 【0178】 The cutting tool T2 attached to the spindle 151 may be a tap tool. After the case 7 and cover 8 are friction stir-welded, a cutting tool T2 (for example, a tap tool) may be used to form threads in the hole (for example, a hole formed in the case 7). 【0179】 After the case 7 and cover 8 are friction stir-welded, the side wall 71 of the case 7 or the inner surface of the case 7 may be cut using a cutting tool T2. 【0180】 In the machine tool 1 of the first embodiment, friction stirring can be performed while the coolant L1 is applied to the case 7. Therefore, distortion of the case 7 due to the heat generated by friction stirring is suppressed. As a result, the machine tool 1 can cut at least one of the case 7 and the cover 8 with high precision following the friction stir welding of the case 7 and the cover 8. 【0181】 (Tool changing device 19) As illustrated in Figure 35, the machine tool 1 may be equipped with a tool changing device 19. The tool changing device 19 can change the friction stir welding tool T1 held on the spindle 151 to a cutting tool T2 (for example, a milling tool T2-1, a drilling tool T2-2, a tapping tool, etc.). 【0182】 In the example shown in Figure 35, the tool changing device 19 includes a tool changing arm 191, an arm rotating device 194 for rotating the tool changing arm 191, and an arm moving device 196 for moving the tool changing arm 191 linearly. The arm rotating device 194 rotates the tool changing arm 191 around the second axis AX2. The arm moving device 196 moves the tool changing arm 191 in a direction parallel to the second axis AX2. 【0183】In the example shown in Figure 35, the tool exchange arm 191 is capable of simultaneously gripping the friction stir welding tool T1 and the cutting tool T2. In the example shown in Figure 35, the tool exchange arm 191 has a first gripping portion 191a for gripping the friction stir welding tool T1 and a second gripping portion 191b for gripping the cutting tool T2. 【0184】 Alternatively, tool changes may be performed manually. Furthermore, if machine tool 1 is a machine capable of performing friction stirring only, tool changes are omitted. 【0185】 (Control device 2) As illustrated in Figure 30, the machine tool 1 may include a control device 2 that controls the rotary drive device 16 and the moving device 17. Additionally, the control device 2 may control the supply device 12. Alternatively, or additionally, the control device 2 may control the tool changer 19. Alternatively, or additionally, the control device 2 may control the actuators 68 (more specifically, the first actuator 68-1 and the second actuator 68-2) that move the anti-detachment member 67. 【0186】 In the example shown in Figure 36, the control device 2 comprises a hardware processor 20 (hereinafter simply referred to as "processor 20"), a memory 22, a communication circuit 24, an input device 26, and a display 27. The processor 20, the memory 22, the communication circuit 24, the input device 26, and the display 27 are connected to each other via a bus 28. In the example shown in Figure 36, the input device 26 includes a touch panel 26t on the display 27. In other words, the display 27 is a display with a touch panel 26t. The input device 26 may include buttons, switches, levers, pointing devices, and / or a keyboard. 【0187】 The memory 22 is a storage medium readable by the processor 20 of the control device 2. The memory 22 may be, for example, a non-volatile or volatile semiconductor memory such as RAM, ROM, or flash memory, or it may be a magnetic disk or other type of memory. 【0188】Memory 22 stores data DA and machining program PM. The processor 20 of the control device 2 executes the machining program PM stored in memory 22, thereby generating control commands. The communication circuit 24 then transmits these control commands to the controlled equipment (more specifically, the rotary drive device 16, the moving device 17, the supply device 12, the tool changer 19, the actuator 68, etc.). In this way, by the processor 20 executing the machining program PM, the control device 2 can control the controlled equipment (more specifically, the rotary drive device 16, the moving device 17, the supply device 12, the tool changer 19, the actuator 68, etc.). 【0189】 (Joining Mode M1) As illustrated in Figure 22, the control device 2 is capable of executing joining mode M1. Joining mode M1 is a mode in which the case 7 and the cover 8 are friction stir-bonded such that a refrigerant flow path 91 is formed by the groove 73v of the case 7 and the cover 8. 【0190】 Furthermore, joining mode M1 is a mode in which the case 7 and the cover 8 are friction stir-bonded using a friction stir-bonding tool T1. More specifically, joining mode M1 is a mode in which the rotating friction stir-bonding tool T1 is moved relative to the case 7 and the cover 8 so that the case 7 and the cover 8 are friction stir-bonded. 【0191】 As illustrated in Figure 30, when the joining mode M1 is executed, the control device 2 transmits a first rotation command R1 to the rotary drive device 16. Upon receiving the first rotation command R1, the rotary drive device 16 rotates the spindle 151 that holds the friction stir welding tool T1 around the first axis AX1. 【0192】 When the joining mode M1 is executed, the control device 2 transmits a first movement command S1 to the moving device 17. Upon receiving the first movement command S1, the moving device 17 moves the rotating friction stir welding tool T1 relative to the case 7 and cover 8 along a first path PA (see Figure 21) specified by the machining program PM. 【0193】The first path PA may include the boundary PA1 between the case 7 and the cover 8. In this case, the case 7 and the cover 8 are butt-joined by friction stir. More specifically, the first path PA may include the boundary PA1-1 between the stepped portion 731 of the case 7 (see Figure 5) and the outer edge portion 81 of the cover 8 (see Figure 5). In this case, the stepped portion 731 of the case 7 and the outer edge portion 81 of the cover 8 are butt-joined by friction stir. 【0194】 As can be seen from Figures 1 and 21, the first path PA may include a path PA2 along the region where the case 7 and the cover 8 are overlapped. In this case, the case 7 and the cover 8 are joined by friction stir. In the example shown in Figure 21, the first path PA includes a path PA2-1 passing through the central portion 83 of the cover 8. In this case, the case 7 and the central portion 83 of the cover 8 are joined by friction stir. 【0195】 In the example shown in Figure 22, at least one of the multiple support columns 42 is located vertically below the central portion 83 of the cover 8. More specifically, when the case 7 and the central portion 83 of the cover 8 are joined together, at least one of the multiple support columns 42 supports the end wall 73 of the case 7 vertically below the friction stir welding tool T1. 【0196】 In the example shown in Figure 21, the first path PA includes both the boundary PA1 between the case 7 and the cover 8 and the path PA2-1 passing through the central portion 83 of the cover 8. In this case, the case 7 and the cover 8 are butt-joined by friction stir, and the central portion 83 of the case 7 and the cover 8 are overlap-joined by friction stir. 【0197】 During the execution of bonding mode M1, the applicator 60 (e.g., a first nozzle 61a and / or a second nozzle 61b) discharges coolant L1 onto the case 7 (e.g., the inner surface 7n of the case 7). More specifically, at least one nozzle 61 (e.g., a first nozzle 61a and / or a second nozzle 61b) sprays coolant L1 onto the inner surface 73n of the end wall 73 of the case 7. 【0198】As illustrated in Figure 24, during the execution of bonding mode M1, at least one nozzle 61 may discharge the coolant L1 to substantially the entire inner surface 73n of the end wall 73, excluding the portion of the inner surface 73n of the end wall 73 that is in contact with the backing member 40. As illustrated in Figure 12, during the execution of bonding mode M1, at least one outer nozzle 62 may discharge the coolant L1 to the outer surface 71t of the side wall 71 of the case 7. 【0199】 As illustrated in Figure 30, when the bonding mode M1 is executed, the control device 2 may transmit a supply command U1 to the supply device 12. The supply device 12 (e.g., pump 121 and / or valve 123) that receives the supply command U1 supplies coolant L1 to the applicator 60 (e.g., first nozzle 61a and / or second nozzle 61b). The applicator 60 (e.g., first nozzle 61a and / or second nozzle 61b) discharges the coolant L1 supplied from the supply device 12 into the case 7. 【0200】 Alternatively, the supply device 12 (e.g., a pump 121 and / or a valve 123) may be operated manually by an operator. More specifically, the machine tool 1 may be equipped with a manual switch for operating the supply device 12. 【0201】 In the example shown in Figure 30, when the bonding mode M1 is executed, the applicator 60 (for example, the first nozzle 61a and / or the second nozzle 61b) releases the coolant L1 only to the case 7 of the case 7 and the cover 8. If the coolant L1 does not reach the cover 8, the coolant L1 does not enter the gap between the case 7 and the cover 8. 【0202】 As illustrated in Figure 17, the execution of the joining mode M1 may be started when the anti-detachment member 67 is in the extended position P1 in contact with the cover 8. More specifically, friction stirring of the case 7 and cover 8 by the friction stir welding tool T1 may be started when the anti-detachment member 67 is in the extended position P1 in contact with the cover 8. In this case, the cover 8 is prevented from detaching from the case 7 when friction stirring is started. 【0203】As illustrated in Figures 17 and 18, the control device 2 may transmit a first operation command to the actuator 68 so that the anti-detachment member 67 moves from the aforementioned advanced position P1 to the aforementioned retracted position P2 in response to the friction stir welding tool T1 approaching the anti-detachment member 67. The control device 2 may determine whether or not the friction stir welding tool T1 is approaching the anti-detachment member 67 based on the machining program PM. Alternatively, the control device 2 may determine whether or not the friction stir welding tool T1 is approaching the anti-detachment member 67 based on a signal from a proximity sensor. 【0204】 As illustrated in Figures 17 and 18, the control device 2 may control the first actuator 68-1 and the second actuator 68-2 so that the first retaining member 67-1 is positioned at a first retracted position P2-1 and the second retaining member 67-2 is positioned at a second extended position P1-2 as the friction stir welding tool T1 approaches the first retaining member 67-1. 【0205】 As illustrated in Figures 19 and 20, the control device 2 may control the first actuator 68-1 and the second actuator 68-2 so that the first retaining member 67-1 is positioned at the first advanced position P1-1 and the second retaining member 67-2 is positioned at the second retracted position P2-2 as the friction stir welding tool T1 approaches the second retaining member 67-2. 【0206】 In the example shown in Figure 13, joining mode M1 is performed with the friction stir welding tool T1 positioned above the backing member 40. If the machine tool 1 is a horizontal machining center, joining mode M1 may be performed with the height of the friction stir welding tool T1 being approximately the same as the height of the backing member 40. 【0207】(Cutting Mode M2) As illustrated in Figures 25 and 30, the control device 2 may selectively execute joining mode M1 and cutting mode M2. Cutting mode M2 ​​is a mode in which at least one of the case 7 and cover 8 is cut using a cutting tool T2. More specifically, cutting mode M2 ​​is a mode in which the rotating cutting tool T2 is moved relative to the case 7 and cover 8 so that at least one of the case 7 and cover 8 is cut. 【0208】 In the examples shown in Figures 25 and 30, the spindle 151 is capable of selectively holding a friction stir welding tool T1 and a cutting tool T2. When welding mode M1 is performed, the spindle 151 holds the friction stir welding tool T1, and when cutting mode M2 ​​is performed, the spindle 151 holds the cutting tool T2. 【0209】 As illustrated in Figure 25, when the cutting mode M2 ​​is executed, the control device 2 transmits a second rotation command R2 to the rotary drive device 16. Upon receiving the second rotation command R2, the rotary drive device 16 rotates the spindle 151 that holds the cutting tool T2 around the first axis AX1. 【0210】 When cutting mode M2 ​​is executed, the control device 2 transmits a second movement command S2 to the moving device 17. Upon receiving the second movement command S2, the moving device 17 moves the rotating cutting tool T2 relative to the case 7 and cover 8 along the second path PB specified by the machining program PM. 【0211】 The second path PB may overlap with the first path PA described above. For example, the control device 2 may control the moving device 17 so that the rotating cutting tool T2 (e.g., milling tool T2-1) moves relative to the case 7 and cover 8 along the second path PB which overlaps with the first path PA described above. In this case, burrs generated during friction stirring are removed by the cutting tool T2 (e.g., milling tool T2-1). 【0212】The second path PB may include a path parallel to the first direction DR1. For example, a rotating cutting tool T2 (e.g., a drilling tool T2-2) may move along the second path PB, thereby forming a hole in the case 7 and / or cover 8. Alternatively, or additionally, a rotating cutting tool T2 (e.g., a tapping tool) may move along the second path PB, thereby forming a screw thread in the aforementioned hole (e.g., a hole formed in the case 7). 【0213】 When cutting mode M2 ​​is performed, cutting fluid may be applied to the cutting tool T2. Alternatively, cutting mode M2 ​​may be performed without applying cutting fluid to the cutting tool T2 (dry cutting). 【0214】 As illustrated in Figure 26, the cutting mode M2 ​​may be performed with the aforementioned anti-detachment member 67 in a retracted position P2 away from the cover 8. More specifically, with the aforementioned anti-detachment member 67 in a retracted position P2 away from the cover 8, at least one of the case 7 and the cover 8 may be cut by the cutting tool T2. 【0215】 If the machine tool 1 does not have the function of cutting a workpiece using a cutting tool, or if there is no need to cut the case 7 and cover 8, the above-described cutting mode M2 ​​is omitted. 【0216】 (Tool change mode M3) In the example shown in Figure 35, the control device 2 is capable of executing tool change mode M3. Tool change mode M3 is a mode in which the friction stir welding tool T1 held on the spindle 151 is replaced with a cutting tool T2. 【0217】More specifically, after the execution of the bonding mode M1 described above, the control device 2 transmits a tool change command C1 to the tool change device 19 so that the friction stir welding tool T1 held on the spindle 151 is replaced with a cutting tool T2. Upon receiving the tool change command C1, the tool change device 19 replaces the friction stir welding tool T1 held on the spindle 151 with a cutting tool T2. After the execution of the tool change mode M3, the cutting mode M2 ​​described above is executed. 【0218】 Alternatively, tool changes may be performed manually. More specifically, the operator may manually remove the friction stir welding tool T1 from the spindle 151 and manually attach the cutting tool T2 to the spindle 151. In this case, the tool change mode M3 described above is omitted. 【0219】 The present invention is not limited to the embodiments or modifications described above, and it is clear that each embodiment or modification can be appropriately modified or changed within the scope of the technical concept of the present invention. Furthermore, the various technologies used in each embodiment or modification can be applied to other embodiments or other modifications, as long as no technical inconsistencies arise. In addition, any optional additional configurations in each embodiment or modification can be omitted as appropriate. 【0220】1...Machine tool, 2...Control device, 3...Work support device, 4...Jig, 7...Case, 7n...Inner surface of case, 8...Cover, 11a...Wall, 11b...Door, 12...Feeding device, 13...Circulation channel, 15...Machining head, 15g...Lower end of machining head, 16...Rotary drive device, 16m...Motor, 17...Movement device, 19...Tool changer, 20...Processor, 22...Memory, 24...Communication circuit, 26...Input device, 26t...Touch panel, 27...Display, 28...Bus, 31...Table, 40...Backing member, 42...Support column, 42-1...First support column, 42-2...Second support column, 42a-1...First End, 42a-2...Second end, 43...Side, 44...First supply channel, 50...Holding member, 51a...First holding member, 51b...Second holding member, 60...Applicator, 61...Nozzle, 61a...First nozzle, 61b...Second nozzle, 62...Outer nozzle, 64...Base, 64-1...First spring, 64-2...Second spring, 65-1...First fixing member, 65-2...Second fixing member, 67...Anti-detachment member, 67-1...First anti-detachment member, 67-2...Second anti-detachment member, 68...Actuator, 68-1...First actuator, 68-2...Second actuator, 71...Side wall, 71-1 ...First side wall, 71-2...Second side wall, 71-3...Third side wall, 71-4...Fourth side wall, 71n...Inner surface of side wall, 71t...Outer surface of side wall, 72...Flange, 72-1...First protruding edge, 72-2...Second protruding edge, 73...End wall, 73n...Inner surface of end wall, 73p...Protrusion, 73t...Outer surface of end wall, 73v...Groove, 74...Recess, 75...Mounting part, 75h...Hole, 79a...First port, 79b...Second port, 81...Outer edge of cover, 83...Central part of cover, 89a...First port, 89b...Second port, 91...Refrigerant flow path, 121...Pump, 123...Valve, 131...Supply flow path, 138...Return flow path , 141...Tank, 143...Chiller, 151...Spindle, 153...Support, 171...Processing head moving device, 178...Table moving device, 178a...X-axis moving device, 178b...Y-axis moving device, 191...Tool changing arm, 191a...First gripping part, 191b...Second gripping part, 194...Arm rotation device, 196...Arm moving device, 421-1...First part, 421-2...Second part, 421-3...Third part, 421-4...Fourth part, 511a...First fixed part, 511b...Second fixed part, 513a...First movable part, 513b...Second movable part, 641...Lower base, 646...Upper base,647...Connecting support, 730...Bottom wall, 731...Stepped section, 738...Recess, AX1...First axis, AX2...Second axis, C1...Tool change command, CB...Lid, DA...Data, DR1...First direction, DR2...Second direction, EB...Structure, F...Fixing member, F1...Bolt, JR...Joining area, L1...Coolant, M1...Joining mode, M2...Cutting mode, M3...Tool change mode, OB...Cooling target, OP...Opening, P1...Advance position, P1-1...First advance position, P1-2...Second advance position, P2...Retracted position, P2-1...First retracted position, P2-2...Second retracted position, PA...First path, PA1...Boundary between case and cover, P A1-1...Boundary between the stepped portion of the case and the outer edge of the cover, PA2...Path along the area where the case and cover overlap, PA2-1...Path passing through the central part of the cover, PB...Second path, PM...Machining program, R1...First rotation command, R2...Second rotation command, RG1...Machining area, S1...First movement command, S2...Second movement command, SB1...First threaded member, SB2...Second threaded member, SN...Spray nozzle, SP...Internal space, SP1...Space between the first retaining member and the second retaining member, T1...Friction stir welding tool, T2...Cutting tool, T2-1...Milling tool, T2-2...Drilling tool, U1...Supply command,

Claims

1. A method for forming a refrigerant flow path, comprising the steps of: preparing a case having a recess defined by a side wall and an end wall and a groove formed on the outer surface of the end wall, and a cover covering the groove; joining the case and the cover by friction stirring so that a refrigerant flow path is formed by the groove and the cover; and discharging coolant from an applicator into the case while performing the friction stirring.

2. The method for forming a refrigerant flow path according to claim 1, wherein, during the execution of friction stirring, the applicator discharges the coolant only to the case among the case and the cover.

3. The method for forming a refrigerant flow path according to claim 2, wherein the case prevents the coolant from reaching the cover.

4. A method for forming a refrigerant flow path according to any one of claims 1 to 3, wherein the coolant is applied to the inner surface of the case during the execution of friction stirring.

5. A method for forming a refrigerant flow path according to any one of claims 1 to 4, wherein the coolant is applied to the outer surface of the side wall during the execution of friction stirring.

6. The method for forming a refrigerant flow path according to any one of claims 1 to 5, wherein the joining step comprises butting the case and the cover together by friction stirring, and overlapping the central portion of the case and the cover together by friction stirring.

7. A method for forming a refrigerant flow path according to any one of claims 1 to 6, wherein, during the execution of friction stirring, the end wall is supported by a backing member, and during the execution of friction stirring, at least one nozzle included in the applicator discharges the coolant to substantially the entire inner surface of the end wall, excluding the portion of the inner surface of the end wall that is in contact with the backing member.

8. A method for forming a refrigerant flow path according to any one of claims 1 to 7, further comprising the step of cutting a part of the joint area between the end wall and the cover.

9. A method for manufacturing a structure having a refrigerant flow path, comprising the steps of: preparing a case having a recess defined by a side wall and an end wall and a groove formed on the outer surface of the end wall, and a cover covering the groove; joining the case and the cover by friction stirring so that a refrigerant flow path is formed by the groove and the cover; discharging coolant from an applicator into the case while the friction stirring is being performed; placing an object to be cooled in the recess; and fixing the cover to the case so that the recess is closed by the cover.

10. A machine tool comprising: a work support device that supports a case having a recess defined by a side wall and an end wall and a groove formed on the outer surface of the end wall, and a cover covering the groove; a spindle capable of holding a friction stir welding tool for joining the case and the cover by friction stir such that a coolant flow path is formed by the groove and the cover; a support that supports the spindle so as to be rotatable around a first axis; a rotation drive device for rotating the spindle around the first axis; a moving device for moving the spindle and the support relative to the work support device; a supply device for supplying coolant to an applicator; and the applicator for discharging the coolant into the case during the execution of the friction stir.

11. The machine tool according to claim 10, wherein when the case and the cover are supported by the work support device, the applicator is positioned opposite the case but not opposite the cover.

12. The machine tool according to claim 10 or 11, wherein the applicator includes at least one nozzle for discharging the coolant onto the inner surface of the case.

13. The machine tool according to any one of claims 10 to 12, wherein the work support device comprises a backing member that supports the end wall of the case and a holding member that holds the side wall of the case.

14. The machine tool according to any one of claims 10 to 13, further comprising a wall surrounding the processing area in which friction stirring is performed.

15. A machine tool according to any one of claims 10 to 14, comprising a rotary drive device and a control device for controlling the moving device, wherein the spindle is capable of holding a cutting tool for cutting at least one of the case and the cover, and the control device is capable of selectively performing a joining mode in which the case and the cover are friction stir-bonded such that the groove and the cover form the refrigerant flow path, and a cutting mode in which at least one of the case and the cover is cut using the cutting tool.

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