Housing for lathe, lathe and method for producing housing for lathe

Abstract

Housing (2) for a lathe (1) configured such that several housings are connected to one another, the housing (2) for a lathe (1) comprising: a first housing (3) containing a first connecting part (32) having a first surface (31) extending along a radial direction of the lathe (1); a second housing (4) containing a second connecting part (42) having a second surface (41) extending along the radial direction and in contact with the first surface (31); and at least one fastening device (5) fastening the first connecting part (32) and the second connecting part (42) in an axial direction of the lathe (1), wherein at least one of the first surface (31) and the second surface (41) includes a rough surface area (7) in at least a part of the first surface (31) or the second surface (41) in which several laser irradiation markings,which are formed by irradiation with laser light, wherein the at least one fastening device (5) comprises: a first arc-shaped element (55) having a first fitting groove adapted from an outside in the radial direction to the first connecting part (32) and the second connecting part (42) and extending along a circumferential direction of the lathe (1), a second arc-shaped element (56) having a second fitting groove adapted from the outside in the radial direction to the first connecting part (32) and the second connecting part (42) and extending along the circumferential direction of the lathe (1), a rotating part (57) configured to rotatably connect an end section of the first arc-shaped element (55) and an end section of the second arc-shaped element (56), and a fastening part (58).which fastens the other end section of the first arc-shaped element (55) and the other end section of the second arc-shaped element (56), wherein in a case where, with respect to an angular position about an axis line (LA) of the lathe (1), a center of rotation (RC) of the turned part (57) is set to 0° and an angular position α is defined such that an angle via the second arc-shaped element (56) from the turned part (57) to the fastened part (58) gradually increases, the rough surface area (7) includes a turned part-side rough surface area (7C) formed within an angular range that satisfies a condition of -60° ≤ α ≤ 60°.

Description

Technical FieldThe present disclosure relates to a shell for a lathe, a lathe, and a method for producing a shell for a lathe.Prior ArtAs a rotary machine, a turbine, an electric motor, a pump, an engine, a turbocharger, and the like are known. Such a lathe is generally provided with a shell to which a plurality of housings are attached.JP 2009-243 299 A, for example, discloses a turbocharger provided with a center housing accommodating a bearing rotatably supporting a turbine shaft, a turbine housing accommodating a turbine impeller connected to one end side of the turbine shaft, and a compressor housing accommodating a compressor impeller connected to the other end side of the turbine shaft. The center housing is disposed between the turbine housing and the compressor housing and is connected to the turbine housing or the compressor housing via a fastening device such as a fastening bolt or a coupling (V-clamp).SUMMARY OF THE INVENTIONTechnical ProblemIn the turbocharger described in JP 2009-243 299 A, in a case where a positional deviation occurs between the housings, an adverse effect such as a malfunction of an actuator in which at least a part thereof is accommodated in the housing may occur. As a means for suppressing the positional deviation between the housings, it is conceivable to suppress rotation of the housings by a positioning pin. However, the positioning pin has a small effect of suppressing the positional deviation between the housings, and the positional deviation between the housings may occur due to wear or damage of the positioning pin. A further turbocharger is known from DE 10 2016 117 960 A1. JP 2021-89 011 A relates to a housing for a flywheel. EP 3 421 813 B1 discloses a housing of a radial compressor and DE 10 2014 113 165 A1 describes a further turbocharger.Further, as the means for suppressing the positional deviation between the housings, it is conceivable to increase a friction coefficient of an abutting part between the housings. In a case where a corrugation is formed on the abutting part by a knurling process using a lathe to prevent slipping, the accuracy of forming the corrugation may be low, and the friction coefficient of the abutting part may be reduced.In view of the above circumstances, an object of at least one embodiment of the present disclosure is to provide a shell for a lathe, a lathe, and a method of producing a shell for a lathe, which are capable of suppressing positional deviation between housings.Solution to the ProblemA shell for a lathe according to an embodiment of the present disclosure is a shell for a lathe configured such that a plurality of housings are connected to each other, the shell for a lathe comprising:a first housing including a first connection part having a first surface extending along a radial direction of the rotary machine,a second housing including a second connection part having a second surface extending along the radial direction and in contact with the first surface, andat least one fixing device that fixes the first connection part and the second connection part in an axial direction of the rotary machine,wherein at least one of the first surface and the second surface includes, in at least a part of the first surface or the second surface, a rough surface region in which a plurality of laser irradiation marks formed by irradiation with laser light are formed.A rotary machine according to an embodiment of the present disclosure includes:the casing, andan impeller rotatably received in the shell.A method for producing a shell for a lathe according to an embodiment of the present disclosure is a method for producing a shell for a lathe configured such that a plurality of housings are connected to each other, the plurality of housings including:a first housing including a first connection part having a first surface extending along a radial direction of the rotary machine, anda second housing including a second connection part having a second surface extending along the radial direction and in contact with the first surface,wherein the method of producing a casing for a lathe comprises:a rough surface area forming step of irradiating at least one of the first surface and the second surface with laser light to form a rough surface area including a plurality of laser irradiation marks.Advantageous Effects of the InventionAccording to at least one embodiment of the present disclosure, the shell for a lathe, the lathe, and the method for producing a shell for a lathe capable of suppressing the positional deviation between the housings are provided.Brief Description of the DrawingsFIG. 1 is a schematic cross-sectional view of a lathe according to an embodiment of the present disclosure. FIG. 2 is an explanatory diagram for describing a rough surface region. FIG. 3 is an explanatory diagram for describing a surface shape of the rough surface region. FIG. 4 is a schematic cross-sectional view of the vicinity of a fixing part between a first housing and a second housing in a case for the lathe according to an embodiment of the present disclosure. FIG. 5 is a schematic diagram showing a state in which a second surface shown in FIG. 4 is visually recognized from an axial direction of the lathe. FIG. 6 is a schematic cross-sectional view of the vicinity of a positioning pin in the shell for the lathe according to an embodiment of the present disclosure. FIG. 7 is a schematic cross-sectional view of the vicinity of the fixing part between the first housing and the second housing in the shell for the rotary machine according to an embodiment of the present disclosure. FIG. 8 is a schematic cross-sectional view of the vicinity of the fixing part between the first housing and the second housing in the shell for the rotary machine according to an embodiment of the present disclosure. FIG. 9 is an explanatory diagram for describing a fastening device shown in FIG. 8. FIG. 10 is a schematic diagram showing a state in which the second surface shown in FIG. 8 is visually recognized from the axial direction of the lathe. FIG. 11 is a flowchart for describing a method of producing the shell for the lathe according to an embodiment of the present disclosure.DESCRIPTION OF EMBODIMENTSHereinafter, some embodiments of the present disclosure will be described with reference to the accompanying drawings. However, dimensions, materials, shapes, relative arrangements, and the like of components described as the embodiments or shown in the drawings are not intended to limit the scope of the present disclosure, and are merely illustrative examples.For example, expressions such as "in a certain direction", "along a certain direction", "parallel", "perpendicular", "center", and "concentric", or "coaxial" representing relative or absolute arrangements not only strictly represent such an arrangement, but also represent a state of relative displacement with tolerance or by an angle or distance to the extent that the same function can be obtained.For example, expressions such as "identical", "same", and "homogeneous" representing that things are in a same state not only represent strictly the same state but also represent a state in which a tolerance or difference to the extent that the same function can be obtained exists.For example, an expression representing a shape such as a quadrangular shape or a cylindrical shape not only represents a shape such as a quadrangular shape or a cylindrical shape in a geometrically strict sense, but also represents a shape including a wave-shaped portion, a chamfered portion, or the like within a range in which the same effect can be obtained.Meanwhile, a term "provided with", "including", or "having" a component is not an exclusive term that excludes the presence of other components.The same reference numerals may be assigned to the same configurations, and description thereof may be omitted.(Rotary Machine)FIG. 1 is a schematic cross-sectional view of a lathe according to an embodiment of the present disclosure. As shown in FIG. 1, a rotary machine 1 is provided with a rotary shaft 11, an impeller 12 attached to the rotary shaft 11, and a shell 2 configured to accommodate the impeller 12. Hereinafter, a direction in which an axis line LA of the rotary shaft 11 (axis line of the rotary machine 1) extends (left-right direction in FIG. 1 ) is defined as an axial direction of the rotary machine 1. A radial direction and a circumferential direction of the rotary machine 1 are respectively defined with reference to the axial direction.The shell 2 is configured such that a plurality of housings (a first housing 3, a second housing 4, and the like) are connected in the axial direction. As shown in FIG. 1, the case 2 is provided with the first housing 3, the second housing 4, and at least one fixing device 5 that fixes the first housing 3 and the second housing 4. The first housing 3 includes a first connection part 32 having a first surface 31 extending along the radial direction of the rotary machine 1. The second housing 4 includes a second connection part 42 having a second surface 41 extending along the radial direction of the rotary machine 1 and in contact with the first surface 31. The second connection part 42 is disposed adjacent to the first connection part 32 in the axial direction of the rotary machine 1.The at least one fastening device 5 is configured to fasten the first connection part 32 and the second connection part 42 in the axial direction. With the fastening of the first connection part 32 and the second connection part 42 in the axial direction via the fastening device 5, the first housing 3 and the second housing 4 are fastened in the axial direction. In a case where the first connection part 32 and the second connection part 42 are fastened in the axial direction via the fastening device 5, the first surface 31 and the second surface 41 are brought into close contact with each other due to fastening strength generated by the fastening device 5, and frictional resistance against positional deviation is generated between the first surface 31 and the second surface 41.(Turbocharger)In the illustrated embodiment, the rotary machine 1 is composed of a turbocharger 6 for an automobile. The turbocharger 6 is provided with the rotating shaft 11, a compressor impeller 61 that is the impeller 12 mounted on one side of the rotating shaft 11, a turbine blade 62 mounted on the other side of the rotating shaft 11, a bearing 63 that rotatably supports the rotating shaft 11, and the shell 2 that accommodates the rotating shaft 11, the compressor impeller 61, the turbine blade 62, and the bearing 63.The shell 2 of the turbocharger 6 is provided with a compressor housing 64 configured to receive the compressor impeller 61, a turbine housing 65 configured to receive the turbine blades 62, a center housing 66 configured to receive the bearing 63, and the at least one fastener 5. The center housing 66 is disposed between the compressor housing 64 and the turbine housing 65 in the axial direction of the rotary machine 1.As shown in FIG. 1, the compressor housing 64 includes a compressor-side connection part 642 having a compressor-side surface 641 extending along the radial direction of the rotary machine 1. The center housing 66 includes a first-center-side connection part 662 having a first-center-side surface 661 that extends along the radial direction of the rotary machine 1 and is in contact with the compressor-side surface 641. The at least one fastening device 5 includes a compressor-side fastening device 5A that fixes the compressor-side connection part 642 and the first-middle-side connection part 662 in the axial direction. With the fastening of the compressor-side connection part 642 and the first-center-side connection part 662 via the fastening device 5A, the compressor housing 64 and the center housing 66 are fastened in the axial direction. In a case where the compressor-side connection part 642 and the first-center-side connection part 662 are fastened via the fastening device 5A, the compressor-side surface 641 and the first-center-side surface 661 are brought into close contact with each other due to the fastening strength generated by the fastening device 5A, and frictional resistance against the positional deviation is generated between the compressor-side surface 641 and the first-center-side surface 661.As shown in FIG. 1, the turbine housing 65 includes a turbine-side connection part 652 having a turbine-side surface 651 extending along the radial direction of the rotary machine 1. The center housing 66 includes a second center-side connection part 664 having a second center-side surface 663 extending along the radial direction of the rotary machine 1 and in contact with the turbine-side surface 651. The at least one fastening device 5 includes a turbine-side fastening device 5B that fixes the turbine-side connection part 652 and the second-center-side connection part 664 in the axial direction. With the attachment of the turbine-side connection part 652 and the second-center-side connection part 664 via the attachment device 5B, the turbine housing 65 and the center housing 66 are attached in the axial direction. In a case where the turbine-side connection part 652 and the second-center-side connection part 664 are fastened via the fastening device 5B, the turbine-side surface 651 and the second-center-side surface 663 are brought into close contact with each other due to the fastening strength generated by the fastening device 5B, and frictional resistance against the positional deviation is generated between the turbine-side surface 651 and the second-center-side surface 663.The first housing 3 may be one of the compressor housing 64 and the center housing 66, and the second housing 4 may be the other of the compressor housing 64 and the center housing 66. Further, the first housing 3 may be one of the turbine housing 65 and the center housing 66, and the second housing 4 may be the other of the turbine housing 65 and the center housing 66.(Rough Surface Area)At least one of the first surface 31 and the second surface 41 includes a rough surface region 7 in at least a part thereof. In the embodiment shown in FIG. 1, the rough surface region 7 is formed on the second surface 41, but may be formed on the first surface 31 or on both the first surface 31 and the second surface 41. As shown in FIG. 1, the rough surface region 7 may be provided on at least one of the surface 641 and the surface 661 where the compressor housing 64 and the center housing 66 are in contact with each other, or may be provided on at least one of the surface 651 and the surface 663 where the turbine housing 65 and the center housing 66 are in contact with each other.FIG. 2 is an explanatory diagram for describing the rough surface region. FIG. 3 is an explanatory diagram for describing a surface shape of the rough surface region. As shown in FIG. 2, a plurality of laser irradiation marks 71 formed by irradiation with laser light are formed in the rough surface region 7. The plurality of laser irradiation marks 71 are formed at positions separated from each other in the rough surface region 7. The plurality of laser irradiation marks 71 are arranged in parallel at intervals from each other along a direction in which a laser irradiation target position moves. As illustrated, the plurality of laser irradiation marks 71 may be arranged offset in the rough surface region 7, or may be arranged in the rough surface region 7 in parallel along two directions that are perpendicular to each other. A region 72 in FIGS. 2 and 3 indicates a region that is not irradiated with the laser light.In the illustrated embodiment, the plurality of laser irradiation marks 71 are formed by the laser light emitted from a laser marking device 8. A laser light output of the laser marking apparatus 8 is 100 W or less. An example of the laser marking apparatus 8 includes an apparatus used for irradiating the laser light to emboss it on an object. In the embodiment shown in FIG. 3, the laser marking apparatus 8 includes a laser light irradiation unit 81 configured to irradiate the laser irradiation target position with the laser light (for example, pulse laser), and an irradiation position adjustment unit 82 configured to adjust the laser irradiation target position. A power of the laser light emitted from the laser light irradiation unit 81 may be set to a predetermined value.In the illustrated embodiment, each of the plurality of laser irradiation marks 71 has a diameter of 10 to 100 μm. Each of the plurality of laser irradiation marks 71 has a depth of 10 to 100 μm with respect to the region 72. Each of the plurality of laser irradiation marks 71 is formed at a position 10 to 100 μm away from other laser irradiation marks 71.As shown in FIG. 3, the rough surface region 7 includes a plurality of recessed portions 73 and a plurality of convex portions 74. The plurality of recessed portions 73 and the plurality of convex portions 74 are formed by the irradiation with the laser light to form the plurality of laser irradiation marks 71. For this reason, at least a part of the plurality of recessed portions 73 is made of the laser irradiation mark 71. In the illustrated embodiment, each of the plurality of convex portions 74 has a depth of 0 to 100 μm with respect to the region 72. As shown in FIG. 3, surface roughness of the rough surface portion 7 is larger than that of the portion 72 not irradiated with the laser light.The shell 2 of the lathe 1 according to some embodiments is provided with the first housing 3 including the first connection part 32 having the first surface 31, the second housing 4 including the second connection part 42 having the second surface 41, and the at least one fastening device 5. At least one of the first surface 31 and the second surface 41 includes, in at least a part thereof, the rough surface region 7 in which the plurality of laser irradiation marks 71 formed by the irradiation with the laser light are formed.With the above configuration, since the rough surface region 7 has a corrugation formed by irradiation with the laser light (recessed portions 73 and convex portions 74), the rough surface region 7 has a rough surface and a large friction coefficient compared to region 72 not irradiated with the laser light. With the provision of the rough surface region 7 having the large friction coefficient on the first surface 31 or the second surface 41, it is possible to increase the frictional resistance between the first surface 31 and the second surface 41. Further, with the provision of the rough surface region 7 on the first surface 31 or the second surface 41, it is possible to improve the adhesiveness between the first surface 31 and the second surface 41. Accordingly, it is possible to suppress the positional deviation between the first housing 3 and the second housing 4.With the suppression of the positional deviation between the first housing 3 and the second housing 4, it is possible to suppress a malfunction of an actuator in which at least a part thereof is accommodated in the case 2, and thus to improve the reliability of the rotary machine 1.In some embodiments, the plurality of laser irradiation marks 71 described above are formed by the laser light emitted from the laser marking device 8 at the laser light power of 100 W or less.With the above configuration, the rough surface region 7 having appropriate surface roughness is formed by irradiating the first surface 31 or the second surface 41 with the laser light having the power of 100 W or less. With the provision of the rough surface portion 7 on the first surface 31 or the second surface 41, it is possible to effectively improve the frictional resistance and the adhesiveness between the first surface 31 and the second surface 41. Accordingly, it is possible to effectively suppress the positional deviation between the first housing 3 and the second housing 4. Further, since the laser marking apparatus 8 having the laser light output of 100 W or less is less expensive than a laser light irradiation apparatus having the laser light output of more than 100 W, it is possible to suppress an increase in equipment cost. In some other embodiments, the plurality of laser irradiation marks 71 may be formed by laser light emitted from the laser light irradiation device having a laser light power of more than 100 W.(Bolt Fixing Structure Between Housings)FIG. 4 is a schematic cross-sectional view of the vicinity of the fixing part between the first housing and the second housing in the shell for the rotary machine according to an embodiment of the present disclosure. FIG. 5 is a diagram showing a state in which a second surface shown in FIG. 4 is visually recognized from an axial direction of the lathe.In some embodiments, as shown in FIG. 4, the first connection part 32 has a recessed portion 33 into which an outer peripheral edge portion 43 of the second connection part 42 can be fitted, and the at least one fastening device 5 ( 5C) includes a support plate 51 and a fastening bolt 52. the support plate 51 includes an inner peripheral portion 511 that clamps the outer peripheral edge portion 43 of the second connection part 42 between the inner peripheral portion 511 and the recessed portion 33 of the first connection part 32, and an outer peripheral portion 512 that protrudes on an outer side of the second connection part 42 in the radial direction of the lathe 1.In the embodiment shown in FIG. 4, the first connection part 32 has a smooth surface 34 extending along the radial direction of the lathe 1 on the outer side of the recessed portion 33 in the radial direction of the lathe 1. The recessed portion 33 is formed to be recessed more than the smooth surface 34 in the axial direction of the rotary machine 1. The first surface 31 is formed on a bottom surface of the recessed portion 33. The second connection part 42 is composed of a protrusion portion that protrudes on the outer side in the radial direction along the radial direction of the rotary machine 1. The recessed portion 33 is composed of an annular recessed portion extending along the circumferential direction of the rotary machine 1, and the second connection part 42 is formed in an annular plate shape to be fitted into the annular recessed portion.In the embodiment shown in FIG. 4, the support plate 51 is formed in an arc shape extending along the circumferential direction of the lathe 1. The support plate 51 may be formed in a circular shape extending along the circumferential direction of the rotary machine 1. A surface 513 of the support plate 51 in the axial direction is in contact with a surface 44 of the second connection part 42 that is opposed to the second surface 41 in the axial direction at the inner peripheral portion 511 and in contact with the smooth surface 34 of the first connection part 32 at the outer peripheral portion 512.In the embodiment shown in FIG. 4, a female screw hole 35 is formed in the smooth surface 34 of the first connection part 32, and a bolt insertion hole 514 is formed in the outer peripheral portion 512 of the support plate 51. The fastening bolt 52 includes a shaft part 521 inserted into the bolt insertion hole 514 and screwed into the first connection part 32, and a head part 522 that holds the outer peripheral portion 512 of the support plate 51 between the head part 522 and the first connection part 32. The shaft part 521 extends along the axial direction and has an external thread portion 523 screwed into the internal thread hole 35 at an outer periphery thereof. The support plate 51 holds the outer peripheral edge portion 43 of the second connection part 42 between the support plate 51 and the recessed portion 33 of the first connection part 32 due to the fastening strength generated by the fastening bolt 52, and thus the first surface 31 and the second surface 41 are brought into close contact with each other, and the frictional resistance against the positional deviation is generated between the first surface 31 and the second surface 41.With the above configuration, the first connection part 32 and the second connection part 42 can be fastened to each other by the support plate 51 and the fastening bolt 52. With the provision of the rough surface portion 7 on the first surface 31 or the second surface 41, it is possible to suppress the positional deviation between the first housing 3 and the second housing 4, and thus to reduce the fastening strength by the fastening bolt 52 by the suppressed amount. Accordingly, it is possible to reduce a diameter of the fastening bolt 52, and thus a degree of freedom of design of the shell 2 or the lathe 1 provided with the shell 2 is improved.FIG. 6 is a schematic cross-sectional view of the vicinity of a positioning pin in the shell for the lathe according to an embodiment of the present disclosure. As shown in FIG. 6, the sheath 2 may be provided with a positioning pin 21 for suppressing the positional deviation between the first connection part 32 and the second connection part 42.In the embodiment shown in FIG. 6, the positioning pin 21 includes a small diameter portion 211 and a large diameter portion 212 having a diameter larger than that of the small diameter portion 211. The small diameter portion 211 is fitted into a small diameter hole 36 formed in the first connection part 32. A notch 37 cut out in an arc shape is formed at an outer peripheral edge of the outer peripheral edge portion 43 of the second connection part 42. An arc-shaped notch 45A forming a large-diameter hole 45 into which the large-diameter portion 212 is fitted is formed between the first connection part 32 and the notch 37 in the first connection part 32. The large diameter hole 45 communicates with the small diameter hole 36 and has a larger diameter than the small diameter hole 36. A circumferential direction position of the second housing 4 corresponding to a circumferential direction position of the first housing 3 is set in advance. The positioning pin 21 positions the first housing 3 and the second housing 4 at circumferential direction positions set in advance.With the above configuration, it is possible to suppress the positional deviation between the first housing 3 and the second housing 4 with the provision of the rough surface portion 7 on the first surface 31 or the second surface 41, and thus to suppress wear or damage of the positioning pin 21. Accordingly, it is possible for the positioning pin 21 to exert the effect of suppressing the positional deviation between the first connection part 32 and the second connection part 42 over a long period of time.As shown in FIG. 4, a conical trapezoidal space 525 is defined, the diameter of which increases from a head part fixing surface 524 of the fixing bolt 52 toward an effective direction (direction toward the first housing 3 along the axial direction, left side in FIG. 5 ) of fixing strength (axial strength) of the fixing bolt 52 by an inclination angle θ with respect to the effective direction of fixing strength. In some embodiments, as shown in FIG. 4, the rough surface region 7 is configured to be present in the conical trapezoidal space 525 that satisfies a condition in which the inclination angle θ is 0° or more and 30° or less. As shown in FIG. 4, the first surface 31 or the second surface 41 includes an action surface 526 of fastening strength provided in the conical trapezoidal space 525. The rough surface portion 7 is formed on the effective surface 526 of fastening strength. The rough surface region 7 does not need to be formed on any surface other than the effective surface 526 of fastening strength of the first surface 31 or the second surface 41.With the above configuration, since the fastening strength of the fastening bolt 52 greatly acts on the tapered trapezoidal space 525, a portion (fastening strength acting surface 526) existing in the tapered trapezoidal space 525 of the first surface 31 or the second surface 41 has a higher surface pressure than the other portions. With the provision of the rough surface region 7 only in the portion (the fastening strength acting surface 526) where the surface pressure is high, it is possible to effectively suppress the positional deviation between the first housing 3 and the second housing 4. Further, with the provision of the rough surface region 7 only in the portion (the acting surface 526 of fastening strength) where the surface pressure is high, it is possible to reduce the rough surface region 7 and thus reduce process costs for forming the rough surface region 7. That is, with the above configuration, the process cost can be reduced while suppressing the positional deviation between the first housing 3 and the second housing 4.In some embodiments, as shown in FIG. 5, the at least one fastening device 5C includes a plurality (six in the illustrated example) of fastening devices 5C arranged at intervals in the circumferential direction of the lathe 1. A plurality (six in the illustrated example) of the conical trapezoidal spaces 525 or the acting surfaces 526 of fastening strength are formed at intervals in the circumferential direction of the lathe 1. As shown in FIG. 5, the rough surface region 7 may be formed on each of the plurality of effective surfaces 526 of fastening strength. In other words, the rough surface region 7 includes a plurality of rough surface regions 7 formed on each of the plurality of fastening strength acting surfaces 526 arranged at intervals in the circumferential direction of the lathe 1. By forming the rough surface portion 7 on each of the plurality of attachment strength acting surfaces 526 in this manner, it is possible to effectively suppress the positional deviation between the first housing 3 and the second housing 4 in the circumferential direction of the rotary machine 1.In some embodiments, as shown in FIG. 5, the rough surface region 7 includes a first rough surface region 7A formed on one surface (second surface 41 in the illustrated example) of the first surface 31 or the second surface 41, and a second rough surface region 7B provided at a position separated from the first rough surface region 7A on the one surface in the circumferential direction of the rotating machine 1.With the above configuration, it is possible to effectively suppress the positional deviation between the first housing 3 and the second housing 4 in the circumferential direction with the provision of the first rough surface region 7A and the second rough surface region 7B at positions separated on the one surface in the circumferential direction of the lathe 1. Further, with the above configuration, it is possible to reduce the rough surface region 7 as compared with a case where the rough surface region 7 is provided over the entire surface of the one surface. Since work time for forming the rough surface region 7 is affected by a surface of the rough surface region 7, it is possible to reduce the process cost for forming the rough surface region 7 with the reduction of the rough surface region 7. That is, with the above configuration, the process cost can be reduced while suppressing the positional deviation between the first housing 3 and the second housing 4.(Bolt Fixing Structure 2 Between Housings)The present disclosure is not limited to the case where the support plate 51 and the fastening bolt 52 fasten the first connection part 32 and the second connection part 42, and is applicable to a case where a fastening bolt 53 described below secures the first connection part 32 and the second connection part 42 and the like.FIG. 7 is a schematic cross-sectional view of the vicinity of the fixing part between the first housing and the second housing in the shell for the rotary machine according to an embodiment of the present disclosure.In some embodiments, as shown in FIG. 7, the fastening device 5 ( 5D) includes the fastening bolt 53. the fastening bolt 53 includes a shaft part 531 that is inserted into a through hole 411 formed in the second connection part 42 and screwed into the first connection part 32, and a head part 532 configured to hold the second connection part 42 between the head part 532 and the first connection part 32.In the embodiment shown in FIG. 7, a female screw hole 311 is formed on the first surface 31, and the through hole 411 is formed on the second surface 41. The shaft part 531 extends along the axial direction and has an externally threaded portion 533 screwed into the internally threaded hole 311 at an outer periphery thereof. With the holding of the second connection part 42 between the head part 532 of the fastening bolt 53 and the first connection part 32 due to the fastening strength generated by the fastening bolt 53, the first surface 31 and the second surface 41 are brought into close contact with each other, and the frictional resistance against the positional deviation is generated between the first surface 31 and the second surface 41.As shown in FIG. 7, in a case where a conical trapezoidal space 535 whose diameter increases from a head part fixing surface 534 of the fixing bolt 53 toward an effective direction (direction toward the first housing 3, left side in FIG. 7 ) of fixing strength (axial strength) of the fixing bolt 53 by an inclination angle θ with respect to the effective direction of fixing strength is defined, the rough surface region 7 is configured to be present in the conical trapezoidal space 535 satisfying a condition in which the inclination angle θ is 0° or more and 30° or less. That is, the rough surface region 7 may be formed on an effective surface 536 of fastening strength that is a portion existing in the conical trapezoidal space 535 on the first surface 31 or the second surface 41. The rough surface region 7 does not need to be formed on any surface other than the effective surface 536 of fastening strength of the first surface 31 or the second surface 41.With the above configuration, the fastening bolt 53 can fasten the first connection part 32 and the second connection part 42. With the provision of the rough surface portion 7 on the first surface 31 or the second surface 41, it is possible to suppress the positional deviation between the first housing 3 and the second housing 4, and thus to reduce the fastening strength by the fastening bolt 53 by the suppressed amount. Accordingly, it is possible to reduce a diameter of the fastening bolt 53, and thus a degree of freedom of design of the shell 2 or the lathe 1 provided with the shell 2 is improved.(Coupling Fixing Structure Between Housings)The present disclosure is not limited to the case where the first connection part 32 and the second connection part 42 are fastened to each other using the fastening bolt, and is also applicable to a case where the first connection part 32 and the second connection part 42 are fastened to each other using a coupling 54 described below.FIG. 8 is a schematic cross-sectional view of the vicinity of the fixing part between the first housing and the second housing in the shell for the rotary machine according to an embodiment of the present disclosure. FIG. 9 is an explanatory diagram for describing the fastening device shown in FIG. 8. FIG. 10 is a diagram showing a state in which the second surface shown in FIG. 8 is visually recognized from the axial direction of the lathe.In some embodiments, as shown in FIG. 9, the fastening device 5 ( 5E) includes the coupling 54 (V-band coupling). The clutch 54 includes a first arcuate member 55 extending along the circumferential direction of the rotary machine 1, a second arcuate member 56 extending along the circumferential direction of the rotary machine 1, a rotating part 57 configured to rotatably connect one end portion 551 of the first arcuate member 55 to one end portion 561 of the second arcuate member 56, and a fixing part 58 fixing the other end portion 552 of the first arcuate member 55 and the other end portion 562 of the second arcuate member 56.As shown in FIG. 8, the first connection part 32 includes a first flange portion 38 protruding on the outer side in the radial direction of the rotary machine 1. A surface of the first flange portion 38 opposite to the first surface 31 in the axial direction may be inclined such that a distance from the first surface 31 to the outer side in the radial direction decreases. The second connection part 42 includes a second flange portion 46 protruding on the outer side in the radial direction of the rotary machine 1. A surface of the second flange portion 46 opposite to the second surface 41 in the axial direction may be inclined such that a distance from the second surface 41 to the outer side in the radial direction decreases.The first arc-shaped member 55 has a first fitting groove 553 fitted to the first flange portion 38 of the first connection part 32 and to the second flange portion 46 of the second connection part 42 from the outer side in the radial direction of the rotary machine 1. The first fitting groove 553 is formed on an inner circumferential side of the first arc-shaped member 55. The second arc-shaped member 56 has a second fitting groove 563 fitted to the first flange portion 38 of the first connection part 32 and to the second flange portion 46 of the second connection part 42 from the outer side in the radial direction of the rotary machine 1. The second fitting groove 563 is formed on an inner circumferential side of the second arc-shaped member 56. In the second arc-shaped member 56, the second fitting groove 563 faces the first fitting groove 553. In the illustrated embodiment, the first arcuate member 55 and the second arcuate member 56 are each formed in a half-arc shape.In the embodiment shown in FIG. 9, the rotating part 57 is configured to rotate the first arc-shaped member 55 about a first rotation center RC 1. Further, the rotating part 57 is configured to rotate the second arc-shaped member 56 about a second rotation center RC 2. As shown in FIG. 9, when viewed from one side in the axial direction, center positions of the first rotation center RC 1 and the second rotation center RC 2 are set as a rotation center RC of the rotating part 57.In the embodiment shown in FIG. 9, the first arc-shaped member 55 includes a first protruding portion 552A that protrudes on the outer side of the other end portion 552 in the radial direction of the lathe 1. The second arc-shaped member 56 includes a second protruding portion 562A protruding on the outer side of the other end portion 562 in the radial direction of the rotary machine 1. The fixing member 58 includes a first fixing member 581 fixed to the first protrusion portion 552A and a second fixing member 582 fixed to the second protrusion portion 562A. With the fastening of the other end portion 552 of the first arc-shaped member 55 to the other end portion 562 of the second arc-shaped member 56 by the fastening part 58 (first fastening part 581, second fastening part 582), a distance between the first fastening part 581 and the second fastening part 582 is shorter than that before the fastening, and thus the first connection part 32 or the second connection part 42 is held in the first fitting groove 553 or the second fitting groove 563. Accordingly, a pressing force toward a mating side in the axial direction acts on the first connection part 32 or the second connection part 42, the first surface 31 and the second surface 41 are brought into close contact with each other, and the frictional resistance against the positional deviation is generated between the first surface 31 and the second surface 41.With the above configuration, the first connection part 32 and the second connection part 42 are held by the first arc-shaped member 55 and the second arc-shaped member 56 with the fastening of the other end portion 552 of the first arc-shaped member 55 and the other end portion 562 of the second arc-shaped member 56 by the fastening part 58. Accordingly, the first connection part 32 and the second connection part 42 can be fixed to each other. With the provision of the rough surface region 7 on the first surface 31 or the second surface 41, it is possible to suppress the positional deviation between the first housing 3 and the second housing 4, and thus to reduce the fastening strength by the fastening device 5 by the suppressed amount. Accordingly, it is possible to reduce a diameter of the fastening device 5E, and thus a degree of freedom of design of the shell 2 or the lathe 1 provided with the shell 2 is improved.As shown in FIG. 10, with respect to an angular position around the axis line LA of the lathe 1, the rotation center RC of the rotating part 57 is set to 0°, and an angular position α is defined such that the angle gradually increases from the rotating part 57 toward the attachment part 58 via the second arc-shaped member 56.As shown in FIG. 10, the rough surface region 7 includes a rotating-part-side rough surface region 7C formed within an angle range satisfying a condition of -60°≤α≤ 60°. With the above configuration, the surface pressure of the rotating part-side rough surface portion 7C is high because the fastening strength of the fastening device 5E (coupling 54) significantly acts on the rotating part-side rough surface portion 7C. With the provision of the rough surface region 7 only in the portion where the surface pressure is high, it is possible to effectively suppress the positional deviation between the first housing 3 and the second housing 4. Further, with the provision of the rough surface region 7 only in the portion where the surface pressure is high, it is possible to reduce the process cost for forming the rough surface region 7 with the reduction of the rough surface region 7. That is, with the above configuration, the process cost can be reduced while suppressing the positional deviation between the first housing 3 and the second housing 4. The rough surface region 7 does not need to be formed in any portion other than the rotating-part-side rough surface region 7C.As shown in FIG. 10, the rough surface region 7 includes a mounting part-side rough surface region 7D formed within an angle range satisfying a condition of 120°≤α≤2400. With the above configuration, the surface pressure of the fastening part-side rough surface portion 7D is high because the fastening strength of the fastening device 5E (coupling 54) significantly acts on the fastening part-side rough surface portion 7D. With the provision of the rough surface region 7 only in the portion where the surface pressure is high, it is possible to effectively suppress the positional deviation between the first housing 3 and the second housing 4. Further, with the provision of the rough surface region 7 only in the portion where the surface pressure is high, it is possible to reduce the process cost for forming the rough surface region 7 with the reduction of the rough surface region 7. That is, with the above configuration, the process cost can be reduced while suppressing the positional deviation between the first housing 3 and the second housing 4. The rough surface region 7 does not need to be formed in any portion other than the fastening member-side rough surface region 7D.In some embodiments, as shown in FIG. 10, the rough surface region 7 includes the rotating part-side rough surface region 7C and the fastening part-side rough surface region 7D. With the above configuration, the process cost can be reduced while suppressing the positional deviation between the first housing 3 and the second housing 4 with the provision of the rough surface region 7 only in the portion (the rotating part-side rough surface region 7C and the attachment part-side rough surface region 7D) in which the surface pressure is high. Further, since the rotating part-side rough surface region 7C and the fixing part-side rough surface region 7D are formed at positions separated from each other in the circumferential direction of the lathe 1, it is possible to effectively suppress the positional deviation in the circumferential direction between the first housing 3 and the second housing 4. The rough surface region 7 does not need to be formed in any portion other than the rotating part-side rough surface region 7C and the fastening part-side rough surface region 7D.In some embodiments, the second housing 4 is formed of a material harder than that of the first housing 3, and the rough surface region 7 is formed on the second surface 41 of the second housing 4. The hardness of the first housing 3 or the second housing 4 can be evaluated based on a test result of a hardness test (for example, measured value of Vickers hardness).In the embodiment shown in FIG. 1, the center housing 66 is formed of a material harder than that of the compressor housing 64. In certain embodiments, a shape of the compressor housing 64 is formed from an aluminum material and a shape of the center housing 66 is formed from a cast iron material. In this case, it is preferable to form the rough surface portion 7 on the first-center-side surface 661 instead of on the compressor-side surface 641.With the above configuration, in a case where the first surface 31 is in contact with the second surface 41, the convex portion 74 formed in the rough surface region 7 bite into the first surface 31 with forming the rough surface region 7 on the second surface 41 of the second housing 4 formed of the material harder than that of the first housing 3, and thus it is possible to improve the adhesiveness between the first surface 31 and the second surface 41. Accordingly, it is possible to effectively suppress the positional deviation between the first housing 3 and the second housing 4.As shown in FIG. 1, the rotary machine 1 according to some embodiments is provided with at least the shell 2 and the impeller 12. With the above configuration, it is possible to suppress the positional deviation between the housings 3 and 4 in the case 2 configured by the plurality of housings (the first housing 3, the second housing 4, and the like), and thus suppress the malfunction of the actuator in which at least a part thereof is accommodated in the case 2. Since the malfunction of the actuator is suppressed, it is possible to improve the reliability of the rotary machine 1.FIG. 11 is a flowchart for describing a method of producing the shell for the lathe according to an embodiment of the present disclosure.As shown in FIG. 11, a method 100 for producing the shell 2 of the lathe 1 according to some embodiments is provided with a rough surface area forming step S 101 of irradiating at least one of the first surface 31 and the second surface 41 with the laser light to form the rough surface area 7 including the plurality of laser irradiation marks 71.As shown in FIG. 11, the method 100 for producing the shell 2 may be further provided with an insert mounting step S 102 of mounting an insert including the center housing 66, a compressor housing mounting step S 103 of mounting the compressor housing 64 to the insert center housing 66, and a turbine housing mounting step S 104 of mounting the turbine housing 65 to the insert center housing 66.In the insert mounting step S 102, the bearing 63, the rotation shaft 11, the compressor impeller 61, and the turbine blade 62 are mounted on the center case 66 to form the insert. In the compressor housing assembling step S 103, the compressor-side connection part 642 and the first-center-side connection part 662 are fastened to each other in the axial direction via the fastening device 5A ( 5). In the turbine housing assembling step S 104, the turbine-side connection part 652 and the second-center-side connection part 664 are fastened to each other via the fastening device 5B ( 5).The method 100 for producing the sheath 2 is not limited to the order shown in FIG. 11. The rough surface area forming step S 101 may be performed before the insert mounting step S 102 or after the insert mounting step S 102. The compressor housing assembling step S 103 may be performed before the turbine housing assembling step S 104 or after the turbine housing assembling step S 104.With the above method, since the rough surface region 7 formed in the rough surface region forming step S 101 has the corrugation formed by irradiation with the laser light, the rough surface region 7 has a rough surface and a large friction coefficient compared to the region 72 that has not been irradiated with the laser light. With the provision of the rough surface region 7 having the large friction coefficient on the first surface 31 or the second surface 41, it is possible to increase the frictional resistance between the first surface 31 and the second surface 41. Further, with the provision of the rough surface region 7 on the first surface 31 or the second surface 41, it is possible to improve the adhesiveness between the first surface 31 and the second surface 41. Accordingly, it is possible to suppress the positional deviation between the first housing 3 and the second housing 4.In some embodiments, in the rough surface area forming step S 101, the rough surface area 7 is formed by the laser light emitted from the laser marking device 8 having the laser light power of more than 100 W.With the above method, the rough surface region 7 having appropriate surface roughness is formed by irradiating the first surface 31 or the second surface 41 with the laser light having the power of 100 W or less. With the provision of the rough surface portion 7 on the first surface 31 or the second surface 41, it is possible to effectively improve the frictional resistance and the adhesiveness between the first surface 31 and the second surface 41. Accordingly, it is possible to effectively suppress the positional deviation between the first housing 3 and the second housing 4. Further, since the laser marking apparatus 8 having the laser light output of 100 W or less is less expensive than a laser light irradiation apparatus having the laser light output of more than 100 W, it is possible to suppress an increase in equipment cost.The present disclosure is not limited to the above-described embodiments, and includes a form in which a modification is added to the above-described embodiments or a form in which the above forms are appropriately combined.The contents described in some embodiments described above are understood to be, for example, as follows.1) A shell (2) for a lathe (1) according to at least one embodiment of the present disclosure is a shell (2) for a lathe (1) configured to connect a plurality of housings to each other, the shell (2) for a lathe (1) comprising:a first housing (3) including a first connection part (32) having a first surface (31) extending along a radial direction of the rotary machine (1),a second housing (4) including a second connection part (42) having a second surface (41) extending along the radial direction and in contact with the first surface (31); andat least one fastening device (5) that fixes the first connection part (32) and the second connection part (42) in an axial direction of the rotary machine (1),wherein at least one of the first surface (31) and the second surface (41) includes, in at least a part of the first surface or the second surface, a rough surface region (7) in which a plurality of laser irradiation marks (71) formed by irradiation with laser light are formed.With the configuration of 1) above, since the rough surface region ( 7) has the corrugation formed by the irradiation with the laser light, the rough surface region ( 7) has a rough surface and a large friction coefficient compared to the region ( 72) not irradiated with the laser light. With the provision of the rough surface area (7) having the large friction coefficient on the first surface (31) or the second surface (41), it is possible to increase the frictional resistance between the first surface (31) and the second surface (41). Further, with the provision of the rough surface area (7) on the first surface (31) or the second surface (41), it is possible to improve the adhesiveness between the first surface (31) and the second surface (41). Accordingly, it is possible to suppress the positional deviation between the first housing ( 3) and the second housing ( 4).2) In some embodiments, in the case ( 2) for a lathe ( 1) according to 1 above, the rough surface region includes ( 7):a first rough surface area (7A) formed on one surface of the first surface (31) or the second surface (41); anda second rough surface portion (7B) provided at a position separated from the first rough surface portion (7A) on the one surface in a circumferential direction of the rotary machine (1).With the configuration of 2) above, it is possible to effectively suppress the positional deviation between the first housing ( 3) and the second housing ( 4) in the circumferential direction with the provision of the first rough surface region ( 7A) and the second rough surface region ( 7B) at positions separated on the one surface in the circumferential direction of the rotary machine ( 1). Further, with the configuration of 2) above, it is possible to reduce the rough surface region ( 7) compared to a case where the rough surface region ( 7) is provided over the entire surface of the one surface. Since work time for forming the rough surface region ( 7) is affected by a surface of the rough surface region ( 7), it is possible to reduce the process cost for forming the rough surface region ( 7) with the reduction of the rough surface region ( 7). That is, with the configuration of 2) above, the process cost can be reduced while suppressing the positional deviation between the first housing ( 3) and the second housing ( 4).3) In some embodiments, in the case (2) for a rotary machine (1) according to 1) or 2) above, the first connection part (32) has a recessed portion (33) into which an outer circumferential edge portion (43) of the second connection part (42) can be fitted, and includes at least one fastening device (5 (5C)).a support plate (51) including an inner peripheral portion (511) that clamps the outer peripheral edge portion (43) of the second connection part (42) between the inner peripheral portion and the recessed portion (33) of the first connection part (32), and an outer peripheral portion (512) that protrudes at an outer side of the second connection part (42) in the radial direction of the rotary machine (1), anda fixing bolt (52) that fixes the outer peripheral portion (512) of the support plate (51) to the first connection part (32).With the configuration of 3) above, the first connection part (32) and the second connection part (42) can be fastened to each other by the support plate (51) and the fastening bolt (52). With the provision of the rough surface region (7) on the first surface (31) or the second surface (41), it is possible to suppress the positional deviation between the first housing (3) and the second housing (4) and thus to reduce the fastening strength by the fastening bolt (52) by the suppressed amount. Accordingly, it is possible to reduce a diameter of the fastening bolt ( 52), and thus a degree of freedom of design of the shell ( 2) or the lathe ( 1) provided with the shell ( 2) is improved.4) In some embodiments, in the case (2) for a lathe (1) according to 3) above, in a case where a conical trapezoidal space (525) whose diameter increases from a head part fixing surface (524) of the fixing bolt (52) toward a fixing strength acting direction of the fixing bolt (52) by an inclination angle θ with respect to the fixing strength acting direction is defined, the rough surface region (7) is configured to be present in the conical trapezoidal space (525) satisfying a condition in which the inclination angle θ is 0° or more and 30° or less.With the configuration of 4) above, since the fastening strength of the fastening bolt (52) greatly acts on the conical trapezoidal space (525), a portion (acting surface 526 of fastening strength) existing in the conical trapezoidal space (525) of the first surface (31) or the second surface (41) has a higher surface pressure than the other portions. With the provision of the rough surface area (7) only in the portion where the surface pressure is high, it is possible to effectively suppress the positional deviation between the first housing (3) and the second housing (4). Further, with the provision of the rough surface area ( 7) only in the portion where the surface pressure is high, it is possible to reduce the process cost for forming the rough surface area ( 7) with the reduction of the rough surface area ( 7). That is, with the configuration of 4) above, the process cost can be reduced while suppressing the positional deviation between the first housing ( 3) and the second housing ( 4).5) In the case of the shell for a lathe, the at least one fastening device includes (5 (5E)).a first arc-shaped member (55) having a first fitting groove (553) fitted to the first connection part (32) and the second connection part (42) from an outer side in the radial direction and extending along a circumferential direction of the rotary machine (1),a second arc-shaped member (56) having a second fitting groove (563) fitted to the first connection part (32) and the second connection part (42) from the outer side in the radial direction and extending along the circumferential direction of the rotary machine (1),a rotating part (57) configured to rotatably connect an end portion (551) of the first arc-shaped member (55) and an end portion (561) of the second arc-shaped member (56); anda fixing part (58) that fixes the other end portion (552) of the first arc-shaped member (55) and the other end portion (562) of the second arc-shaped member (56).With the configuration of 5) above, the first connection part (32) and the second connection part (42) are held by the first arc-shaped member (55) and the second arc-shaped member (56) with the fastening of the other end portion (552) of the first arc-shaped member (55) and the other end portion (562) of the second arc-shaped member (56) by the fastening part (58). Accordingly, the first connection part (32) and the second connection part (42) can be fixed to each other. With the provision of the rough surface region ( 7) on the first surface ( 31) or the second surface ( 41), it is possible to suppress the positional deviation between the first housing ( 3) and the second housing ( 4) and thus to reduce the fastening strength by the fastening device ( 5) by the suppressed amount. Accordingly, it is possible to reduce a diameter of the fastening device ( 5E), and thus a degree of freedom of design of the shell ( 2) or the lathe ( 1) provided with the shell ( 2) is improved.6) In some embodiments, in the shell (2) for a rotary machine (1) according to 5) above, in a case where, with respect to an angular position about an axis line (LA) of the rotary machine (1), a rotation center of the rotary part (57) is set to 0° and an angular position α is defined such that an angle gradually increases from the rotary part (57) toward the attachment part via the second arc-shaped member (56), the rough surface region (7) includes a rotary part-side rough surface region (7C) formed within an angular range satisfying a condition of - 60°≤α≤ 60°.With the configuration of 6) above, the surface pressure of the rotating-part-side rough surface region ( 7C) is high because the fastening strength of the fastening device ( 5E coupling 54) significantly acts on the rough surface region ( 7C). With the provision of the rough surface area (7) only in the portion where the surface pressure is high, it is possible to effectively suppress the positional deviation between the first housing (3) and the second housing (4). Further, with the provision of the rough surface area ( 7) only in the portion where the surface pressure is high, it is possible to reduce the process cost for forming the rough surface area ( 7) with the reduction of the rough surface area ( 7). That is, with the configuration of 6) above, the process cost can be reduced while suppressing the positional deviation between the first housing ( 3) and the second housing ( 4).7) In some embodiments, in the shell (2) for a lathe (1) according to 5) or 6) above, in a case where, with respect to an angular position about an axis line (LA) of the lathe (1), a rotation center of the rotating part (57) is set to 0° and an angular position α is defined such that an angle gradually increases from the rotating part (57) toward the fixing part (58) via the second arc-shaped member (56), the rough surface region (7) includes a fixing-part-side rough surface region (7D) formed within an angular range satisfying a condition of 120°≤α≤240 °.With the configuration of 7) above, the surface pressure of the fastening part-side rough surface region ( 7D) is high because the fastening strength of the fastening device ( 5E coupling 54) significantly acts on the fastening part-side rough surface region ( 7D). With the provision of the rough surface area (7) only in the portion where the surface pressure is high, it is possible to effectively suppress the positional deviation between the first housing (3) and the second housing (4). Further, with the provision of the rough surface area ( 7) only in the portion where the surface pressure is high, it is possible to reduce the process cost for forming the rough surface area ( 7) with the reduction of the rough surface area ( 7). That is, with the configuration of 6) above, the process cost can be reduced while suppressing the positional deviation between the first housing ( 3) and the second housing ( 4).8) In some embodiments, in the case (2) for a lathe (1) according to 1) or 2) above, the at least one fastening device (5 (5D)) includes:a fastening bolt (53) including:a shaft part (531) inserted into a through hole (411) formed in the second connection part (42) and screwed into the first connection part (32); anda head portion (532) configured to hold the second connection portion (42) between the head portion (532) and the first connection portion (32).With the configuration of 8) above, the fastening bolt ( 53) can fasten the first connection part ( 32) and the second connection part ( 42). With the provision of the rough surface region ( 7) on the first surface ( 31) or the second surface ( 41), it is possible to suppress the positional deviation between the first housing ( 3) and the second housing ( 4) and thus to reduce the fastening strength by the fastening bolt ( 53) by the suppressed amount. Accordingly, it is possible to reduce a diameter of the fastening bolt ( 53), and thus a degree of freedom of design of the shell ( 2) or the lathe ( 1) provided with the shell ( 2) is improved.9) In some embodiments, in the case (2) for a lathe (1) according to any one of 1) to 8) above, the second housing (4) is formed of a material harder than a material of the first housing (3), and the rough surface region (7) is formed on the second surface (41) of the second housing (4).With the configuration of 9) above, in a case where the first surface (31) is in contact with the second surface (41), the convex portion (74) formed in the rough surface region (7) bite into the first surface (31) with forming the rough surface region (7) on the second surface (41) of the second housing (4) formed of the material harder than a material of the first housing (3), and thus it is possible to improve the adhesiveness between the first surface (31) and the second surface (41). Accordingly, it is possible to effectively suppress the positional deviation between the first housing ( 3) and the second housing ( 4).10) In some embodiments, in the case (2) for a lathe (1) according to any one of 1) to 9) above, the plurality of laser irradiation marks (71) are formed by the laser light emitted from a laser marking device (8) having a laser light output of 100 W or less.With the configuration of 10) above, the rough surface region ( 7) having appropriate surface roughness is formed by irradiating the first surface ( 31) or the second surface ( 41) with the laser light having the power of 100 W or less. With the provision of the rough surface portion (7) on the first surface (31) or the second surface (41), it is possible to effectively improve the frictional resistance and the adhesiveness between the first surface (31) and the second surface (41). Accordingly, it is possible to effectively suppress the positional deviation between the first housing ( 3) and the second housing ( 4). Further, since the laser marking apparatus ( 8) having the laser light output of 100 W or less is less expensive than a laser light irradiation apparatus having the laser light output of more than 100 W, it is possible to suppress an increase in equipment cost.11) A rotary machine (1) according to at least one embodiment of the present disclosure comprises:the casing (2) for a lathe (1) according to any one of 1) to 10) above, andan impeller (12) rotatably received in the shell (2).With the configuration of 11) above, it is possible to suppress the positional deviation between the housings (3, 4) in the case (2) configured by the plurality of housings (the first housing 3, the second housing 4, and the like), and thus suppress the malfunction of the actuator in which at least a part thereof is accommodated in the case (2). Since the malfunction of the actuator is suppressed, it is possible to improve the reliability of the rotary machine ( 1).12) A method (100) for producing a shell (2) for a lathe (1) according to at least one embodiment of the present disclosure is a method (100) for producing a shell (2) for a lathe (1) configured such that a plurality of housings (3, 4) are connected to each other, the plurality of housings (3, 4) including:a first housing (3) including a first connection part (32) having a first surface (31) extending along a radial direction of the rotary machine (1), anda second housing (4) including a second connection part (42) having a second surface (41) extending along the radial direction and in contact with the first surface (31),wherein the method (100) for producing a casing (2) for a lathe (1) comprises:a rough area forming step (S 101) of irradiating at least one of the first area (31) and the second area (41) with laser light to form a rough area (7) including a plurality of laser irradiation marks (71).According to the method of 12) above, since the rough surface region ( 7) formed in the rough surface region forming step (S 101) has the corrugation formed by irradiation with the laser light, the rough surface region ( 7) has a rough surface and a large friction coefficient compared to the region ( 72) that has not been irradiated with the laser light. With the provision of the rough surface region (7) having the large friction coefficient on the first surface (31) or the second surface (41), it is possible to increase the frictional resistance between the first surface (31) and the second surface (42). Further, with the provision of the rough surface area (7) on the first surface (31) or the second surface (41), it is possible to improve the adhesiveness between the first surface (31) and the second surface (41). Accordingly, it is possible to suppress the positional deviation between the first housing ( 3) and the second housing ( 4).13) In some embodiments, in the method (100) for producing a shell (2) for a lathe (1) according to 12) above, in the rough surface area forming step (S 101), the rough surface area (7) is formed by the laser light emitted from a laser marking device (8) having a laser light output of 100 W or less.With the method of 13) above, the rough surface region ( 7) having appropriate surface roughness is formed by irradiating the first surface ( 31) or the second surface ( 41) with the laser light having the power of 100 W or less. With the provision of the rough surface portion (7) on the first surface (31) or the second surface (41), it is possible to effectively improve the frictional resistance and the adhesiveness between the first surface (31) and the second surface (41). Accordingly, it is possible to effectively suppress the positional deviation between the first housing ( 3) and the second housing ( 4). Further, since the laser marking apparatus ( 8) having the laser light output of 100 W or less is less expensive than a laser light irradiation apparatus having the laser light output of more than 100 W, it is possible to suppress an increase in equipment cost.List of reference characters1 Lathe 2 Shell 3 First housing 4 Second housing 5, 5A to 5E Fixing device 6 Turbocharger 7 Rough surface region 7A First rough surface region 7B Second rough surface region 7C Rotating-part-side rough surface region 7D Fixing-part-side rough surface region 8 Laser marking device 11 Rotating shaft 12 Impeller 21 Positioning pin 31 First surface 32 First connection part 33 Recessed portion 41 Second surface 42: Second connection part 51 Support plate 52, 53 Mounting bolt 54 Clutch 55 First arcuate member 56 Second arcuate member 57 Rotating part 58 Mounting part 61 Compressor impeller 62 Turbine blade 63 Bearing 64 Compressor housing 65 Turbine housing 66 Center housing 71 Laser irradiation mark 72 Region 73 Recessed portion 74 Convex portion 81 Laser light irradiation unit 82 Irradiation position adjustment unit 100 Method of producing sheath LA axis line RC rotation center

Claims

A shell (2) for a lathe (1) configured such that a plurality of housings are connected to each other, the shell (2) for a lathe (1) comprising: a first housing (3) including a first connection part (32) having a first surface (31) extending along a radial direction of the lathe (1); a second housing (4) including a second connection part (42) having a second surface (41) extending along the radial direction and contacting the first surface (31); and at least one fixing device (5) fixing the first connection part (32) and the second connection part (42) in an axial direction of the lathe (1), wherein at least one of the first surface (31) and the second surface (41) includes, in at least a part of the first surface (31) or the second surface (41), a rough surface region (7) in which a plurality of laser irradiation marks formed by irradiation with laser light are formed, the at least one fixing device (5) including: a first arc-shaped member (55) having a first fitting groove fitted to the first connecting part (32) and the second connecting part (42) from an outer side in the radial direction and extending along a circumferential direction of the lathe (1); a second arc-shaped member (56) having a second fitting groove fitted to the first connecting part (32) and the second connecting part (42) from the outer side in the radial direction and extending along the circumferential direction of the lathe (1); a rotating part (57), that is configured to rotatably connect one end portion of the first arc-shaped member (55) and one end portion of the second arc-shaped member (56), and a fixing part (58) that fixes the other end portion of the first arc-shaped member (55) and the other end portion of the second arc-shaped member (56), wherein in a case where, with respect to an angular position around an axis line (LA) of the lathe (1), a rotation center (RC) of the rotating part (57) is set to 0° and an angular position α is defined such that an angle via the second arc-shaped member (56) gradually increases from the rotating part (57) toward the fixing part (58), the rough surface region (7) includes a rotating part-side rough surface region (7C) formed within an angular range satisfying a condition of -60°≤α≤ 60°.A shell (2) for a lathe (1) configured such that a plurality of housings are connected to each other, the shell (2) for a lathe (1) comprising: a first housing (3) including a first connection part (32) having a first surface (31) extending along a radial direction of the lathe (1); a second housing (4) including a second connection part (42) having a second surface (41) extending along the radial direction and contacting the first surface (31); and at least one fixing device (5) fixing the first connection part (32) and the second connection part (42) in an axial direction of the lathe (1), wherein at least one of the first surface (31) and the second surface (41) includes, in at least a part of the first surface (31) or the second surface (41), a rough surface region (7) in which a plurality of laser irradiation marks formed by irradiation with laser light are formed, the at least one fixing device (5) including: a first arc-shaped member (55) having a first fitting groove fitted to the first connecting part (32) and the second connecting part (42) from an outer side in the radial direction and extending along a circumferential direction of the lathe (1); a second arc-shaped member (56) having a second fitting groove fitted to the first connecting part (32) and the second connecting part (42) from the outer side in the radial direction and extending along the circumferential direction of the lathe (1); a rotating part (57), that is configured to rotatably connect one end portion of the first arc-shaped member (55) and one end portion of the second arc-shaped member (56), and a fixing part (58) that fixes the other end portion of the first arc-shaped member (55) and the other end portion of the second arc-shaped member (56), wherein in a case where, with respect to an angular position around an axis line (LA) of the lathe (1), a rotation center (RC) of the rotating part (57) is set to 0° and an angular position α is defined such that an angle via the second arc-shaped member (56) gradually increases from the rotating part (57) toward the fixing part (58), the rough surface region (7) includes a fixing part-side rough surface region (7C) formed within an angular range satisfying a condition of 120°≤α≤2400°, contains.The shell (2) for a lathe (1) according to claim 1 or 2, wherein the rough surface region (7) includes: a first rough surface region (7A) formed on one surface of the first surface (31) or the second surface (41); and a second rough surface region (7B) provided at a position separated from the first rough surface region (7A) on the one surface in a circumferential direction of the lathe (1).The shell (2) for a lathe according to any one of claims 1 to 3, wherein the second housing is formed of a material harder than a material of the first housing, and the rough surface region (7) is formed on the second surface (41) of the second housing (4).The sheath (2) for a lathe according to any one of claims 1 to 4, wherein the plurality of laser irradiation marks are formed by the laser light emitted from a laser marking device (8) having a laser light output of 100 W or less.A rotary machine (1) comprising: the shell (2) according to any one of claims 1 to 5; and an impeller (12) rotatably accommodated in the shell (2).A method for producing a shell (2) for a lathe (1) configured such that a plurality of housings are connected to each other, the shell (2) including: a first housing (3) including a first connection part (32) having a first surface (31) extending along a radial direction of the lathe (1); a second housing (4) including a second connection part (42) having a second surface (41) extending along the radial direction and contacting the first surface (31); and at least one fastening device (5) configured to fasten the first connection part (32) and the second connection part (42) in the axial direction, wherein the method for producing a cover (2) for a lathe (1) comprises: a rough surface area forming step (7) of irradiating at least one of the first surface (31) and the second surface (41) with laser light to form a rough surface area (7) including a plurality of laser irradiation marks, wherein the at least one fixing device (5) includes: a first arcuate member (55) having a first fitting groove that is fitted to the first connecting part (32) and the second connecting part (42) from an outer side in the radial direction and extends along a circumferential direction of the lathe (1); a second arcuate member (56) having a second fitting groove that is fitted to the first connecting part (32) and the second connecting part (42) from the outer side in the radial direction and extends along the circumferential direction of the lathe (1), a rotating part (57) configured to rotatably connect one end portion of the first arc-shaped member (55) and one end portion of the second arc-shaped member (56), and a fixing part (58) fixing the other end portion of the first arc-shaped member (55) and the other end portion of the second arc-shaped member (56), wherein in a case where, with respect to an angular position around an axis line (LA) of the lathe (1), a rotation center (RC) of the rotating part (57) is set to 0° and an angular position α is defined such that an angle via the second arc-shaped member (56) gradually increases from the rotating part (57) toward the fixing part (58), the rough surface region (7) includes a rotating part-side rough surface region (7C) formed within an angular range, which satisfies a condition of -60°≤α≤ 60°.A method for producing a shell (2) for a lathe (1) configured such that a plurality of housings are connected to each other, the shell (2) including: a first housing (3) including a first connection part (32) having a first surface (31) extending along a radial direction of the lathe (1); a second housing (4) including a second connection part (42) having a second surface (41) extending along the radial direction and contacting the first surface (31); and at least one fastening device (5) configured to fasten the first connection part (32) and the second connection part (42) in the axial direction, wherein the method for producing a cover (2) for a lathe (1) comprises: a rough surface area forming step (7) of irradiating at least one of the first surface (31) and the second surface (41) with laser light to form a rough surface area (7) including a plurality of laser irradiation marks, wherein the at least one fixing device (5) includes: a first arcuate member (55) having a first fitting groove that is fitted to the first connecting part (32) and the second connecting part (42) from an outer side in the radial direction and extends along a circumferential direction of the lathe (1); a second arcuate member (56) having a second fitting groove that is fitted to the first connecting part (32) and the second connecting part (42) from the outer side in the radial direction and extends along the circumferential direction of the lathe (1), a rotating part (57) configured to rotatably connect one end portion of the first arc-shaped member (55) and one end portion of the second arc-shaped member (56), and a fixing part (58) fixing the other end portion of the first arc-shaped member (55) and the other end portion of the second arc-shaped member (56), wherein in a case where, with respect to an angular position around an axis line (LA) of the lathe (1), a rotation center (RC) of the rotating part (57) is set to 0° and an angular position α is defined such that an angle via the second arc-shaped member (56) gradually increases from the rotating part (57) toward the fixing part (58), the rough surface region (7) includes a fixing part-side rough surface region (7D) formed within an angular range, which satisfies a condition of 120°≤α≤2407.The method for producing a shell (2) for a lathe (1) according to claim 7 or 8, wherein in the rough surface area forming step (7), the rough surface area (7) is formed by the laser light emitted from a laser marking device (8) having a laser light output of 100 W or less.

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