JP5024163B2 - Compressor manufacturing method - Google Patents

Description

    The present invention relates to a method of manufacturing a compressor having a cylindrical wall in which a rotating body rotates.

    Conventionally, a single screw compressor used as a compressor for refrigeration and air conditioning is known. For example, the single screw compressor of Patent Document 1 includes a screw rotor having a plurality of spiral grooves on the outer peripheral surface and two disk-shaped gate rotors having a plurality of teeth. The screw rotor is rotatably fitted in a cylindrical wall provided in the casing of the compressor, and the outer peripheral surface of the tooth tip is surrounded by the cylindrical wall. The gate rotor is configured such that the teeth penetrate the cylindrical wall and mesh with the screw rotor. The two gate rotors are provided symmetrically with the axis perpendicular to the axis of the screw rotor and sandwiching the screw rotor. Two compression chambers are formed in the cylindrical wall by the inner peripheral surface of the cylindrical wall, the tooth groove of the screw rotor, and the teeth of the gate rotor.

    In this single screw compressor, as the screw rotor rotates, the teeth of the gate rotor move through the tooth grooves of the screw rotor, and the operation of reducing the volume of the compression chamber after the expansion is repeated. While the volume of the compression chamber expands, the refrigerant is sucked into the compression chamber, and when the volume of the compression chamber starts to shrink, the sucked refrigerant is compressed. When the tooth gap, which is the compression chamber, communicates with the discharge port, the compressed high-pressure refrigerant is discharged from the compression chamber.

By the way, with respect to the casing casting of the single screw compressor, in order to confirm its soundness, a pressure resistance test defined by a law relating to high pressure gas is performed. In the pressure resistance test, the cylindrical wall of the casing is final machined (finished) to finish to the final dimensions, and then the inside of the casing is pressurized at a pressure 1.5 times the design pressure. Conventionally, the inside of the casing is not pressurized before the finishing process, and is pressurized for the first time in the pressure resistance test after the finishing process.
JP-A-6-42474

    However, local stress concentration occurs on the cylindrical wall due to the test pressure applied to the casing in the pressure test, and as a result of the stress exceeding the yield stress of the material, it is inevitable that it remains as a permanent strain even after the test pressure is removed. . Therefore, even if the inner shape of the cylindrical wall (also referred to as a casing bore) is finished in a shape close to a perfect circle by the final finishing process, the casing bore becomes, for example, an elliptical shape because permanent deformation occurs in the subsequent pressure test. The gap distribution with the screw rotor becomes non-uniform, which causes a reduction in the performance of the compressor.

    The present invention has been made in view of such a point, and an object of the present invention is to improve the performance of the compressor by reducing the deformation amount of the cylindrical wall after the pressure resistance test as much as possible. It is in.

    In order to achieve the above object, in the present invention, a pressure larger than the design pressure is applied to the inside of the cylindrical wall (30) before being finished.

    Specifically, the first invention has a substantially cylindrical cylindrical wall (30) provided in the casing (10), and a rotating body (40) that rotates inside the cylindrical wall (30). The present invention is directed to a method of manufacturing a compressor that compresses a fluid inside the cylindrical wall (30) by rotating the rotating body (40). And, a casting step (ST1) for forming a cast body in which at least a part becomes the cylindrical wall (30), a finishing step (ST4) for finishing the cast body to form the cylindrical wall (30), It has a pressure test process (ST5) that applies a test pressure larger than the design pressure inside the cylindrical wall (30) that has been finished, and the interior of the cylindrical wall (30) before the finish processing is greater than the design pressure. It has a pre-pressurizing step (ST3) for applying a large pressure.

    In the first invention, when the compressor is manufactured, first, the casting process (ST1) is performed, and a cast body in which at least a part becomes the cylindrical wall (30) is formed by casting. Next, a pre-pressurization step (ST3) is performed, and a pressure larger than the design pressure is applied to the inside of the cylindrical wall (30) before finishing. The cylindrical wall (30) is distorted by pressurizing the inside, and exceeds the yield stress of the material of the cylindrical wall (30), resulting in permanent strain and deformation. Next, a finishing step (ST4) is performed, and the cast body is finished to form a cylindrical wall (30). This reduces the amount of deformation of the cylindrical wall (30) due to the permanent strain generated in the pre-pressurization step (ST3).

    Next, a pressure test step (ST5) is performed, and a test pressure larger than the design pressure is applied to the interior of the finished cylindrical wall (30). The cylindrical wall (30) may be distorted by pressurizing the inside again, but strain hardening occurs by pressurization in the pre-pressurization step (ST3), and the yield stress of the cylindrical wall (30) is increased. Therefore, the amount of change in the cylindrical wall (30) due to pressurization in this pressure resistance test step (ST5) is suitably reduced. As a result, the non-uniformity of the gap between the rotating body (40) and the cylindrical wall (30) is reduced, and the performance of the compressor is improved. A compressor is manufactured by the above process.

    A second invention is characterized in that, in the first pressurization step (ST3), pressurization and depressurization inside the cylindrical wall (30) are repeated a plurality of times in the first pressurization step.

    In the second invention, it is possible to reliably cause strain hardening of the cylindrical wall (30) by repeating the pressurization and decompression inside the cylindrical wall (30) a plurality of times.

    According to a third invention, in the first invention, in the preliminary pressurizing step (ST3), the inside of the cylindrical wall (30) is pressurized with a pressure of 1.5 times or more the design pressure. . The fourth invention is characterized in that, in the first invention, the inside of the cylindrical wall (30) is pressurized at a pressure equal to or higher than the test pressure in the preliminary pressurizing step (ST3).

    In the third and fourth inventions, since the inside of the cylindrical wall (30) is pressurized with a sufficiently high pressure, it becomes possible to cause sufficient strain hardening in the cylindrical wall (30). Therefore, deformation of the cylindrical wall (30) is suitably suppressed in the pressure resistance test step (ST5).

    The fifth invention is characterized in that, in the first invention, a roughing step (ST2) for roughing the cast body is performed before the pre-pressurizing step (ST3).

    In the fifth aspect of the invention, the roughing process (ST2) is performed after the casting process (ST1), and the cast body before being finished is roughly processed. Therefore, finishing can be performed easily and with high accuracy. Thereafter, the pre-pressurization step (ST3) described above is performed to pressurize the cylindrical wall (30).

    In a sixth aspect based on the first aspect, the rotor (40) is rotatably fitted to the cylindrical wall (30) and has a helical tooth groove (41) on the outer peripheral surface. (40), wherein the compressor includes a gate rotor (50) penetrating the cylindrical wall (30) and meshing with a tooth groove (41) of the screw rotor (40).

    In the sixth invention, the compressor constitutes a screw compressor. That is, a compression chamber is formed between the cylindrical wall (30), the tooth groove (41) of the screw rotor (40), and the gate rotor (50). And the volume of a compression chamber increases / decreases, when a tooth gap (41) moves with rotation of a screw rotor (40). By increasing or decreasing the volume of the compression chamber, the fluid sucked from one end (suction side end) of the tooth groove (41) is compressed and discharged from the other end (discharge side end) of the tooth groove (41).

    According to the first aspect of the invention, since the pre-pressurizing step (ST3) for applying a pressure larger than the design pressure to the inside of the cylindrical wall (30) before finishing is performed, the cylindrical wall (30) It is possible to increase the yield stress by causing strain hardening to the material in advance, and to suppress deformation of the cylindrical wall (30) due to pressurization in the pressure resistance test step (ST5). Further, the deformation of the cylindrical wall (30) generated in the pre-pressurization step (ST3) can be appropriately reduced in the subsequent finishing process. As a result, the amount of deformation of the cylindrical wall (30) after the pressure test can be reduced, so that the performance of the compressor can be dramatically improved.

    According to the second invention, in the pre-pressurization step (ST3), the pressurization and depressurization inside the cylindrical wall (30) are repeated a plurality of times, so that the strain hardening of the cylindrical wall (30) is ensured. Can be generated.

    According to the third and fourth aspects of the invention, in the pre-pressurization step (ST3), by sufficiently pressurizing the inside of the cylindrical wall (30) with a sufficiently high pressure, sufficient strain hardening is applied to the cylindrical wall (30) in advance. Therefore, the deformation of the cylindrical wall (30) can be more suitably suppressed in the pressure resistance test step (ST5).

    According to the fifth aspect, since the roughing process (ST2) is performed before the pre-pressurization process (ST3), the finishing process can be performed easily and with high accuracy.

    According to the sixth aspect of the present invention, since the amount of deformation after the pressure resistance test can be reduced for the cylindrical wall (30) of the screw compressor, the performance of the screw compressor can be dramatically improved.

    Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

    Drawing 1 is a longitudinal section showing the composition of the important section of the single screw compressor (1) concerning an embodiment. 2 is a cross-sectional view taken along the line II-II in FIG. FIG. 3 is a plan view showing configurations of the screw rotor (40) and the gate rotor (50) according to the embodiment. FIG. 4 is a perspective view of the configuration of the screw rotor (40) and the gate rotor (50) according to the embodiment as viewed from the discharge side end. FIG. 5 is a perspective view showing a suction stroke of the compression mechanism (20) according to the embodiment. FIG. 6 is a perspective view showing a compression stroke of the compression mechanism (20) according to the embodiment. FIG. 7 is a perspective view illustrating a discharge stroke of the compression mechanism (20) according to the embodiment. FIG. 8 is a flowchart showing manufacturing steps of the single screw compressor (1) according to the embodiment.

    The single screw compressor (1) of the present embodiment (hereinafter simply referred to as a screw compressor (1)) is for refrigeration and air conditioning, and is provided in a refrigerant circuit for performing a refrigeration cycle to compress refrigerant. is there.

    As shown in FIG. 1 and FIG. 2, the screw compressor (1) is configured as a completely sealed type. The screw compressor (1) includes a compression mechanism (20) that introduces low-pressure gas into the casing (10) and compresses the low-pressure gas. An electric motor (not shown) is fixed in the casing (10), and the electric motor and the compression mechanism (20) are connected by a drive shaft (21) that is a rotating shaft. Further, in the casing (10), a low-pressure gas refrigerant is introduced from an evaporator (not shown) of a refrigerant circuit and a low-pressure space (S1) for guiding the low-pressure gas to the compression mechanism (20), and a compression A high-pressure space (S2) into which the high-pressure gas refrigerant discharged from the mechanism (20) flows is partitioned.

    The compression mechanism (20) includes a cylindrical wall (30) formed in the casing (10), one screw rotor (40) disposed in the cylindrical wall (30), and the screw rotor (40 And two (a pair of) gate rotors (50) meshing with each other. The screw rotor (40) is mounted on the drive shaft (21) and is prevented from rotating with respect to the drive shaft (21) by a key (22).

    As shown also in FIG. 3 and FIG. 4, a plurality (6 in this embodiment) of helical tooth grooves (41) are formed on the outer peripheral surface of the screw rotor (40). The screw rotor (40) is rotatably fitted to the cylindrical wall (30), and the outer peripheral surface of the tooth tip is surrounded by the cylindrical wall (30). On the other hand, each gate rotor (50) is formed in a disk shape having a plurality (11 in this embodiment) of flat teeth (51) on the outer peripheral surface. Each gate rotor (50) is symmetrically disposed on the outside of the cylindrical wall (30) with the screw rotor (40) interposed therebetween, and the axis is perpendicular to the axis of the screw rotor (40). And each gate rotor (50) is comprised so that a flat tooth (51) may penetrate a part of cylindrical wall (30), and may mesh | engage with the tooth groove (41) of a screw rotor (40). The screw rotor (40) is made of metal, and the gate rotor (50) is made of resin.

    The tip of the drive shaft (21) is rotatably supported by a bearing holder (60) located on the high pressure side (right side in FIG. 1) of the compression mechanism (20). The bearing holder (60) is adjacent to the high pressure side end face (right side in FIG. 1) of the screw rotor (40), and supports the drive shaft (21) via a ball bearing (61).

    The screw compressor (1) is provided with a slide valve (70) as a capacity control mechanism. The slide valve (70) is provided in a slide valve housing portion (31) in which a cylindrical wall (30) bulges radially outward at two locations in the circumferential direction. The slide valve (70) is configured such that its inner surface forms part of the inner peripheral surface of the cylindrical wall (30) and is slidable in the axial direction of the cylindrical wall (30). In FIG. 1, when the slide valve (70) slides to the right, an axial clearance is formed between the end surface (P1) of the slide valve housing (31) and the end surface (P2) of the slide valve (70). . This axial clearance is configured as a bypass passage (33) for returning the refrigerant from the compression chamber (23) to the low pressure space (S1). Therefore, the capacity control of the compression mechanism (20) can be performed by adjusting the opening degree of the bypass passage (33). Further, the slide valve (70) is formed with a discharge port (25) through which the compression chamber (23) communicates with the high-pressure space (S2).

    The screw compressor (1) is provided with a slide valve drive mechanism (80) for slidingly driving the slide valve (70). The slide valve drive mechanism (80) includes a cylinder (81) fixed to the bearing holder (60), a piston (82) loaded in the cylinder (81), and a piston rod ( 83), a connecting rod (85) for connecting the arm (84) and the slide valve (70), and a spring for biasing the arm (84) to the right in FIG. 86). The slide valve drive mechanism (80) is configured such that the slide valve (70) is biased to the right in FIG. 1 by a spring (86), while applying a differential pressure to the left and right end faces of the piston (82). The movement of the piston (82) is controlled and the position of the slide valve (70) is adjusted. That is, in the cylinder (81), a low pressure pressure acts on the left space of the piston (82), and a high pressure acts on the right space of the piston (82).

    As shown in FIG. 2, each of the gate rotors (50) is disposed in a gate rotor chamber (90) defined in the casing (10) adjacent to the cylindrical wall (30). A driven shaft (94), which is a rotation shaft, is connected to the center of the gate rotor (50). The driven shaft (94) is rotatably supported by a bearing housing (91) provided in the gate rotor chamber (90). The bearing housing (91) supports the driven shaft (94) via the ball bearings (92, 93) and supports the gate rotor (50) in a cantilever manner. Each gate rotor chamber (90) communicates with the low pressure space (S1).

    In the compression mechanism (20), a space surrounded by the inner peripheral surface of the cylindrical wall (30), the tooth groove (41) of the screw rotor (40), and the spur tooth (51) of the gate rotor (50) is formed. It becomes a compression chamber (23). In FIGS. 1, 3, and 4, the screw rotor (40) has a left end that is a suction side end and a right end that is a discharge side end. And the outer peripheral part of the suction | inhalation side edge part of a screw rotor (40) is formed in the taper shape. The tooth groove (41) of the screw rotor (40) is open to the low pressure space (S1) at the suction side end, and this open part is the suction port (24) of the compression mechanism (20).

    The compression mechanism (20) is configured so that the spur tooth (51) of the gate rotor (50) moves in the tooth groove (41) of the screw rotor (40) as the screw rotor (40) rotates. The enlargement operation and the reduction operation of (23) are repeated. Thereby, the refrigerant | coolant suction process, a compression process, and a discharge process are performed in order.

-Driving action-
Next, the operation of the single screw compressor (1) will be described.

    When the electric motor is started in the single screw compressor (1), the screw rotor (40) rotates as the drive shaft (21) rotates. As the screw rotor (40) rotates, the gate rotor (50) also rotates, and the compression mechanism (20) repeats the suction stroke, the compression stroke, and the discharge stroke.

    In the compression mechanism (20), as shown in FIGS. 5 to 7, when the screw rotor (40) rotates, the volume of the compression chamber (23) is changed by the movement of the tooth gap (41) (that is, the spur tooth ( Perform the operation of reducing after enlarging with the movement of 51). While the volume of the compression chamber (23) increases, the low-pressure gas refrigerant in the low-pressure space (S1) is sucked into the compression chamber (23) through the suction port (24) (suction stroke, see FIG. 5). As the rotation of the screw rotor (40) proceeds, the compression chamber (23) is partitioned by the spur teeth (51) of the gate rotor (50), and the expansion operation of the volume of the compression chamber (23) ends and shrinks. Operation starts. While the volume of the compression chamber (23) is reduced, the sucked refrigerant is compressed (compression stroke, see FIG. 6). The compression chamber (23) moves to the right side of FIG. 6 as the screw rotor (40) further rotates, and eventually communicates with the discharge port (25). Thus, when the discharge side end of the compression chamber (23) is opened, the high-pressure gas refrigerant is discharged from the compression chamber (23) to the high-pressure space (S2) (discharge process, see FIG. 7). The “compression chamber (23)” referred to here is indicated by hatching in FIGS.

-Manufacturing method-
Next, a manufacturing method of the single screw compressor (1) will be described with reference to FIG.

    When manufacturing this single screw compressor (1), as shown in FIG. 8, a casting process (ST1) is first performed, and a cast body in which at least a part becomes a cylindrical wall (30) is formed by casting. That is, the cast body later constitutes the casing (10).

    Next, a roughing process (ST2) is performed, and the above-mentioned cast body is roughly processed to remove unnecessary protrusions and the like formed on the cast body.

    Next, a pre-pressurization step (ST3) is performed, and a pressure larger than the design pressure is applied to the inside of the cylindrical wall (30) before finishing. If the inside of the casing (10) is pressurized, not only the inside of the cylindrical wall (30) but also the whole inside the casing (10) including the space that becomes the low pressure space (S1) and the high pressure space (S2) is pressurized. . The pressure applied at this time is equal to or higher than the test pressure applied to the cylindrical wall (30) in the subsequent pressure resistance test step (ST5). The test pressure is stipulated to be 1.5 times or more the design pressure according to laws and regulations (refrigeration and safety regulation related examples). Therefore, in this pre-pressurization step, the inside of the cylindrical wall (30) is pressurized with a pressure 1.5 times the design pressure. In addition, the said pressure is good also as 1.5 times or more of design pressure.

    Furthermore, in this pre-pressurization step (ST3), pressurization and decompression inside the cylindrical wall (30) are repeated a plurality of times. For example, during pressurization, a pressure 1.5 times the design pressure is applied for a certain period of time. Thereafter, during decompression, the inside of the cylindrical wall (30) is decompressed to atmospheric pressure for a fixed time.

    As a result, a strain is generated in the pressurized cylindrical wall (30), and a permanent strain is generated by exceeding the yield stress of the material of the cylindrical wall (30), so that the cylindrical wall (30) remains deformed. That is, the inner surface shape (hereinafter referred to as the casing bore) of the cross section perpendicular to the axial direction of the cylindrical wall (30) expands from a circular shape at the beginning of casting to an elliptical shape and deforms. On the other hand, the yield stress of the cylindrical wall (30) before finishing is increased by strain hardening.

    Next, a finishing step (ST4) is performed, and the cast body is finished by machining to form a cylindrical wall (30). This reduces the amount of deformation of the cylindrical wall (30) due to the permanent strain generated in the pre-pressurization step (ST3) so that the casing bore has a shape close to a perfect circle.

    Next, a pressure test step (ST5) is performed, and a test pressure larger than the design pressure (for example, 1.5 times the design pressure) is applied to the interior of the finished cylindrical wall (30). The cylindrical wall (30) may be distorted by pressurizing the inside again, but the yield stress of the cylindrical wall (30) is increased by strain hardening generated in the pre-pressurization step (ST3). Therefore, the amount of change in the cylindrical wall (30) due to pressurization in this pressure test step (ST5) is reduced. As a result, the non-uniformity of the gap between the screw rotor (40) and the cylindrical wall (30) is reduced, and the performance of the screw compressor (1) is improved. A screw compressor (1) is manufactured by performing the above steps.

    Here, examples in which the casing bores in the cylindrical wall (30) after the pre-pressurization step (ST3), the finishing step (ST4), and the pressure resistance test step (ST5) were actually measured will be described. 9 to 11, the distance from the axial center of the cylindrical wall (30) to the inner wall surface is measured at a plurality of points in the inner circumferential direction and plotted with ♦.

    After the pre-pressurization step (ST3), as shown in FIG. 9, it can be seen that it is deformed into an ellipse that expands substantially in the vertical direction. The roundness at this time is 1.0.

    After the finishing process (ST4), as shown in FIG. The roundness at this time was 0.30.

    After the pressure resistance test step (ST5), as shown in FIG. 11, it can be seen that it is slightly deformed into an elliptical shape that slightly expands in the vertical direction in FIG. The roundness at this time was 0.37.

    Therefore, according to this embodiment, it was confirmed that the casing bore after the pressure resistance test step (ST5) is maintained at a high roundness.

-Effect of the embodiment-
By the way, if the pre-pressurization step (ST3) is not performed, the screw compressor is manufactured through a casting step, a roughing step, a finishing step, and a pressure test step in order. In the pressure test process, a relatively large permanent strain is generated in the cylindrical wall (30). Therefore, even if the casing bore of the cylindrical wall (30) is formed in a perfect circle shape with high accuracy in the finishing process, after the pressure resistance test, as shown by a two-dot chain line A in FIG. It will be greatly deformed into an elliptical shape.

    In particular, the cylindrical wall (30) of the screw compressor (1) is opened so that the spur teeth (51) of the gate rotor (50) can penetrate, so the rigidity is relatively low. It is easy to deform.

    On the other hand, according to this embodiment, since the pre-pressurization step (ST3) for applying a pressure larger than the design pressure to the inside of the cylindrical wall (30) before finishing is performed, the cylindrical wall ( 30) can be strain-hardened in advance to increase its yield stress, and deformation of the cylindrical wall (30) due to pressurization in the pressure test step (ST5) can be suppressed. Further, the deformation of the cylindrical wall (30) generated in the pre-pressurization step (ST3) can be appropriately reduced in the subsequent finishing process, and the casing bore can be formed in a shape close to a perfect circle. As a result, the amount of deformation of the cylindrical wall (30) after the pressure test can be reduced, so that the unevenness of the gap between the screw rotor (40) and the cylindrical wall (30) is reduced, and the screw compressor (1) Performance can be improved dramatically.

    Furthermore, in this embodiment, in the pre-pressurization step (ST3), the pressurization and depressurization inside the cylindrical wall (30) are repeated a plurality of times, so that the strain hardening of the cylindrical wall (30) is surely generated. Can be made.

    Furthermore, in the pre-pressurization step (ST3), the inside of the cylindrical wall (30) is pressurized with a sufficiently high pressure 1.5 times higher than the design pressure. Strain hardening can be caused, and deformation of the cylindrical wall (30) can be more suitably suppressed in the pressure resistance test process. Further, since the roughing process (ST2) is performed before the pre-pressurization process (ST3), the finishing process can be performed easily and with high accuracy.

<< Other Embodiments >>
In the above embodiment, the screw compressor has been described as an example. However, the present invention is not limited to this, and a substantially cylindrical cylindrical wall provided in the casing, and a rotating body that rotates inside the cylindrical wall; The method of manufacturing the compressor that compresses the fluid inside the cylindrical wall by rotating the rotating body can be similarly applied. Therefore, for example, the present invention can be applied to a method of manufacturing another compressor such as a turbo compressor having an impeller as a rotating body.

    In the above embodiment, the pressurization and depressurization inside the cylindrical wall (30) are repeated a plurality of times in the pre-pressurization step (ST3). However, the present invention is not limited to this, and the cylindrical wall (30) The inner pressure may be one time.

    In addition, the above embodiment is an essentially preferable illustration, Comprising: It does not intend restrict | limiting the range of this invention, its application thing, or its use.

    As described above, the present invention is useful for a method of manufacturing a compressor that compresses a fluid by rotating a rotating body inside a cylindrical wall.

Drawing 1 is a longitudinal section showing the composition of the important section of the single screw compressor concerning an embodiment. 2 is a cross-sectional view taken along the line II-II in FIG. FIG. 3 is a plan view showing configurations of a screw rotor and a gate rotor according to the embodiment. FIG. 4 is a perspective view of the configuration of the screw rotor and the gate rotor according to the embodiment as viewed from the discharge side end. FIG. 5 is a perspective view illustrating a suction stroke of the compression mechanism according to the embodiment. FIG. 6 is a perspective view illustrating a compression stroke of the compression mechanism according to the embodiment. FIG. 7 is a perspective view illustrating a discharge stroke of the compression mechanism according to the embodiment. FIG. 8 is a flowchart illustrating a manufacturing process of the compressor according to the embodiment. FIG. 9 is a graph showing the measurement result of the casing bore after the pre-pressurization step. FIG. 10 is a graph showing the measurement result of the casing bore after the finishing process. FIG. 11 is a graph showing the measurement result of the casing bore after the pressure resistance test process.

Explanation of symbols

ST1 Casting process
ST2 Roughing process
ST3 Pre-pressurization process
ST4 Finishing process
ST5 Pressure test process
1 Single screw compressor
10 Casing
30 cylindrical wall
40 Screw rotor (rotary body)
41 tooth gap
50 Gate rotor

Claims (6)

A substantially cylindrical cylindrical wall (30) provided in the casing (10) and a rotating body (40) rotating inside the cylindrical wall (30), and the rotating body (40) rotates. A method of manufacturing a compressor for compressing fluid inside the cylindrical wall (30),
A casting step (ST1) for forming a cast body, at least part of which is the cylindrical wall (30);
A finishing step (ST4) for finishing the cast body to form the cylindrical wall (30);
A pressure test step (ST5) for applying a test pressure larger than the design pressure inside the cylindrical wall (30) that has been finished;
A method for manufacturing a compressor, comprising: a pre-pressurizing step (ST3) for applying a pressure larger than a design pressure inside a cylindrical wall (30) before finishing. In the manufacturing method of the compressor according to claim 1,
In the pre-pressurization step (ST3), the pressurizing and depressurizing inside the cylindrical wall (30) is repeated a plurality of times. In the manufacturing method of the compressor according to claim 1,
In the preliminary pressurizing step (ST3), the inside of the cylindrical wall (30) is pressurized with a pressure of 1.5 times or more the design pressure. In the manufacturing method of the compressor according to claim 1,
In the pre-pressurizing step (ST3), the inside of the cylindrical wall (30) is pressurized with a pressure equal to or higher than the test pressure. In the manufacturing method of the compressor according to claim 1,
A compressor manufacturing method comprising a roughing step (ST2) for roughing the cast body before the pre-pressurizing step (ST3). In the manufacturing method of the compressor according to claim 1,
The rotating body (40) is a screw rotor (40) that is rotatably fitted to the cylindrical wall (30) and has a helical tooth groove (41) on the outer peripheral surface,
The compressor is provided with a gate rotor (50) that penetrates the cylindrical wall (30) and meshes with a tooth groove (41) of the screw rotor (40).

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