JP2009281181A - Manufacturing method for screw rotor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress axial displacement of spiral grooves with respect to the rotating shaft of a screw rotor. <P>SOLUTION: This manufacturing method for the screw rotor includes: a supporting step of rotatably supporting a screw rotor base material 120 around the rotating shaft A; a first machining step of machining the spiral grooves 41 and first and second reference surfaces 48a, 48b as columnar surfaces with the rotating shaft A as a center from the screw rotor material 120 while the screw rotor material 120 supported in the supporting step is rotated around the rotating shaft A; a resupporting step of resupporting the screw rotor material 120 with the reference surfaces 48a, 48b as basis; and a second machining step of machining an insertion hole 47 for inserting a shaft member from the screw rotor material 120 supported in the resupporting step so that the axis center of the insertion hole 47 matches the axis centers of the first and second reference surfaces 48a, 48b. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a screw rotor manufacturing method for manufacturing a screw rotor that is attached to a shaft member and supported rotatably in a screw compressor by processing a screw rotor base material.

  Conventionally, a single screw compressor has been used as a compressor for compressing refrigerant and air. For example, Patent Document 1 discloses a single screw compressor including one screw rotor and two gate rotors.

  In this single screw compressor, the screw rotor is generally formed in a columnar shape, and a plurality of spiral grooves are carved on the outer peripheral portion thereof. The gate rotor is generally formed in a flat plate shape, and a plurality of rectangular plate gates are provided radially. The gate rotor is installed on the side of the screw rotor so that its rotation axis is orthogonal to the rotation axis of the screw rotor, and the gate is engaged with the spiral groove of the screw rotor. The screw rotor and the gate rotor are accommodated in a casing, and a compression chamber is formed by the spiral groove of the screw rotor, the gate of the gate rotor, and the inner wall surface of the casing. When the screw rotor is rotationally driven by an electric motor or the like, the gate rotor rotates as the screw rotor rotates. Then, the gate of the gate rotor relatively moves from the upstream end to the downstream end of the meshed spiral groove, and the volume of the compression chamber that is completely closed is gradually reduced. As a result, the fluid in the compression chamber is compressed.

  As described above, the screw rotor has a spiral groove and has a complicated shape. Such a screw rotor is manufactured by a processing apparatus as shown in Patent Document 2.

In the processing apparatus disclosed in Patent Document 2, the tool and the screw rotor base material are relatively displaced along the three axes and relatively rotated around the two axes, and the screw rotor base material is moved by the tool. Process the screw rotor. Here, a hole for inserting a shaft member is formed in the screw rotor base material processed by this processing apparatus, and the screw rotor base material is inserted into the base material support portion of the processing apparatus. The central axis is installed so as to coincide with the rotation axis of the base material support. And the process of a spiral groove is performed with respect to the screw rotor base material installed in this way.
JP 2002-202080 A US Pat. No. 6,122,824

  By the way, the screw rotor completed by processing the spiral groove by the processing device is removed from the base material support portion, the shaft member is inserted into the hole for inserting the shaft member, and incorporated into the casing of the screw compressor.

  Here, there is a shape error in the hole for inserting the shaft member of the screw rotor base material, and an installation error occurs when the screw rotor base material is installed in the base material support portion. For this reason, the axial center of the hole and the rotation axis of the base material support portion do not coincide with each other, and the axial center of the hole and the axial center of the spiral groove processed in the screw rotor base material may be misaligned. When such a screw rotor is incorporated into a screw compressor, the spiral groove rotates in a state of being eccentric with respect to the rotation axis of the screw rotor. As a result, in the screw compressor, the gap distribution between the spiral groove and the gate of the gate rotor becomes non-uniform, so that the gap becomes larger during compression and refrigerant leaks, or conversely the gap becomes smaller and the gate becomes smaller. When the screw and the spiral groove interfere with each other, the performance of the screw compressor is deteriorated.

  The present invention has been made in view of such a point, and an object thereof is to suppress axial misalignment of the spiral groove with respect to the rotational axis of the screw rotor.

  In the present invention, after the screw rotor base material is processed with the spiral groove and the reference surface in the same rotational support state, the screw rotor base material is supported again with reference to the reference surface, and the screw rotor base material is inserted into the shaft member. A common hole or a shaft member inserted through the hole is finished with reference to the reference surface.

  Specifically, in the first invention, the screw rotor (40) attached to the shaft member (21) and rotatably supported in the screw compressor (1) is processed into the screw rotor base material (120). The screw rotor manufacturing method manufactured in this way is the object. And a support step for rotatably supporting the screw rotor base material (120) around a predetermined rotation axis (A), and the screw rotor base material (120) supported in the support step around the rotation axis (A). A first processing step of processing a reference surface (48a, 48b) which is a cylindrical surface centered on the spiral groove (41) and the rotation axis (A) in the screw rotor base material (120), A re-supporting step for re-supporting the screw rotor base material (120) with reference to the reference surfaces (48a, 48b), and a hole for inserting a shaft member in the screw rotor base material (120) supported in the re-supporting step (47) includes a second machining step in which the axis of the hole (47) is machined so as to coincide with the axis of the reference plane (48a, 48b).

  In the case of the above-described configuration, the spiral groove (41) is processed in the screw rotor base material (120) that is rotatably supported around the predetermined rotation axis (A), and the cylindrical surface centered on the rotation axis (A) is used as a reference Processed as surfaces (48a, 48b). Then, the screw rotor base material (120) is re-supported with reference to the reference plane (48a, 48b), and the shaft member insertion hole (47) has its axis as the axis of the reference plane (48a, 48b). Process to match your heart.

  That is, the axis of the spiral groove (41) and the axis of the reference surface (48a, 48b) are coincident with each other, and the axis of the shaft member insertion hole (47) is the reference surface (48a, 48b). Therefore, the axial center of the spiral groove (41) and the axial center of the hole (47) can be matched with high accuracy. As a result, axial misalignment of the spiral groove (41) with respect to the rotational axis of the screw rotor (40) can be suppressed.

  According to a second invention, in the first invention, the screw rotor base material (120) is formed with a pilot hole (121) for a shaft member insertion hole (47). The screw rotor base material (120) is attached to a shaft-shaped jig (340) provided rotatably around a predetermined rotation axis (A) through the lower hole (121), and the re-supporting step Then, the screw rotor base material (120) is removed from the jig (340), and the screw rotor base material (120) is re-supported with reference to the reference surfaces (48a, 48b), and the second machining step Then, the said lower hole (121) of the said screw rotor base material (120) shall be processed, and the finishing process of the said hole (47) for shaft member insertion shall be performed.

  In the case of the above configuration, the screw rotor base material (120) is formed with a pilot hole (121) for the shaft member insertion hole (47) at a stage before the support step. Then, the shaft-like jig (340) is inserted through the prepared hole (121), and the supporting step and the processing step are performed. Here, whether or not the axial center of the lower hole (121) coincides with the rotation axis (A) in the supporting process is determined according to the shape accuracy of the lower hole (121), the shape accuracy of the jig (340) and the jig ( 340) and the accuracy of the attachment of the lower hole (121), etc., it is unclear how much the axial center of the lower hole (121) matches the rotational axis (A) in the support process. However, since the spiral groove (41) and the reference surfaces (48a, 48b) are processed with respect to the screw rotor base material (120) having the same support state, at least the axial center of the spiral groove (41) and the reference surfaces (48a, 48b) It is consistent with the axis of 48b).

  Thereafter, the screw rotor base material (120) is supported again with reference to the reference surfaces (48a, 48b), and the shaft member insertion hole (47) of the screw rotor base material (120) is formed in the reference surface ( By finishing with reference to 48a, 48b), the axial center of the hole (47) and the axial center of the reference surface (48a, 48b) can be matched with high accuracy.

  As a result, the axial center of the spiral groove (41) and the axial center of the shaft member insertion hole (47) can be made to coincide with each other with high accuracy regardless of the shape accuracy of the lower hole (121).

  3rd invention is a screw rotor which manufactures the screw rotor (40) which is attached to the shaft member (21) in the screw compressor (1) and is rotatably supported by processing the screw rotor base material (120). The manufacturing method is the target. And a supporting step of supporting the screw rotor base material (120) formed with the shaft member insertion hole (47) rotatably around a predetermined rotation axis (A), and the screw rotor supported in the supporting step While rotating the base material (120) around the rotation axis (A), the screw rotor base material (120) has a spiral groove (41) and a reference surface which is a cylindrical surface centering on the rotation axis (A) ( 48a, 48b), a shaft member (21) is inserted into the hole (47) of the screw rotor base material (120), and the screw rotor base material (120) is moved to the reference plane. (48a, 48b) and the re-supporting step for re-supporting, and the shaft member (21) in the state of re-supporting the screw rotor base material (120), when the shaft member (21) is mounted on the screw compressor (1) (14, 61) The supported parts (21a, 21b) are supported by the axis of the supported parts (21a, 21b). Serial reference surface (48a, 48b) is intended to include a second processing step of processing to match the axis of the.

  In the case of the above-described configuration, the spiral groove (41) is machined in the screw rotor base material (120) rotatably supported around the predetermined rotation axis (A), and the cylindrical surface centering on the rotation axis (A) is used as the reference plane. Process as (48a, 48b). Then, after the shaft member (21) is inserted into the hole (47) of the screw rotor base material (120), the screw rotor base material (120) is re-supported with reference to the reference surfaces (48a, 48b). . Thus, in the state where the screw rotor base material (120) is re-supported, the axis of the supported portion (21a, 21b) of the shaft member (21) coincides with the axis of the reference surface (48a, 48b). To be processed.

  That is, the axis of the spiral groove (41) and the axis of the reference surface (48a, 48b) coincide with each other, and the axis of the supported portion (21a, 21b) of the shaft member (21) is the reference surface. (48a, 48b) and the axial center of the spiral groove (41) and the axis of the supported portion (21a, 21b) of the shaft member (21) can be matched with high accuracy. . As a result, axial misalignment of the spiral groove (41) with respect to the rotational axis of the screw rotor (40) can be suppressed.

  According to a fourth invention, in any one of the first to third inventions, in the second processing step, the outer shape of the screw rotor base material (120) is further determined, and the axis of the outer shape is the reference plane. It shall be finished so as to coincide with the axis of (48a, 48b).

  In the case of the above configuration, in the second processing step, the screw rotor base material (120) is further processed by finishing the outer peripheral shape of the screw rotor base material (120) with reference to the reference surfaces (48a, 48b). ) Of the outer peripheral shape can be matched with the axis of the hole (47) or the axis of the supported portion (21a, 21b) of the shaft member (21) with high accuracy.

  According to a fifth invention, in any one of the first to fourth inventions, the screw rotor (40) has an outer diameter smaller than a portion (40a) in which the spiral groove (41) is formed. A small diameter portion (46) is provided at one end of the axial direction, and the small diameter portion (46) includes a bearing holder (60) when the screw rotor (40) is mounted on the screw compressor (1). And a bent gap is formed between the bearing holder (60) and the screw rotor (40). In the first processing step, the reference surface (48a) is The small diameter part (46) shall be processed.

  In the case of the above configuration, the reference surface (48a) is processed into the portion having another use in the screw rotor (40) as a finished product by processing the reference surface (48a) in the small diameter portion (46). It is not necessary to provide a place for processing the reference surface (48a).

  According to a sixth invention, in any one of the first to fourth inventions, a portion of the screw rotor base material (120) where the reference surface (48b) is processed is deleted after the second processing step. A deletion step is further included.

  In the case of the above configuration, the reference surface (48b) is processed into an unnecessary portion in the screw rotor (40) as a finished product. By doing so, the reference surface (48b) can be processed without being restricted by the shape of the screw rotor (40) as a finished product. That is, the shape of the reference surface (48b) and the place to be processed can be determined in consideration of the ease of making the screw rotor base material (120) and the ease of processing of the reference surface (48b).

  According to a seventh invention, in any one of the first to sixth inventions, in the first machining step, after the spiral groove (41) is machined in the screw rotor base material (120), the reference surface (48a 48b).

  In the case of the above configuration, the machining of the spiral groove (41) has a large cutting resistance, and the weight of the screw rotor base material (120) before the spiral groove processing is heavy, so that before and after the processing of the spiral groove (41) Therefore, there is a possibility that the screw rotor base material (120) is displaced from the rotation axis (A) in the supporting process. However, at the final stage of the processing of the spiral groove (41) in which the spiral groove (41) is substantially processed to reduce cutting resistance and the weight of the screw rotor base material (120) is reduced, the screw rotor base material (120) There is almost no deviation from the rotation axis (A). Therefore, by processing the reference surface (48a, 48b) after processing the spiral groove (41), the rotation axis when processing the spiral groove and the rotation axis when processing the reference surface (48a, 48b) are matched with high accuracy. As a result, the axial center of the spiral groove (41) and the axial center of the reference plane (48a, 48b) can be matched with high accuracy.

  According to the present invention, the spiral groove (41) and the reference surfaces (48a, 48b) are machined in a state where the screw rotor base material (120) is rotatably supported around the predetermined rotation axis (A). Then, the screw rotor base material (120) is re-supported with reference to the reference surfaces (48a, 48b), and the screw rotor base material (120) is re-supported with reference to the reference surfaces (48a, 48b). By machining the shaft member insertion hole (47), the axial center of the spiral groove (41) and the shaft center of the shaft member insertion hole (47) can be matched with high accuracy. As a result, in the screw compressor (1), the axial displacement of the spiral groove (41) with respect to the rotation shaft of the screw rotor (40) can be suppressed, and the performance of the screw compressor (1) can be improved.

  According to the second aspect of the present invention, the screw rotor base material (120) has the shaft member insertion hole (47) with the lower hole (121) formed in advance, and the lower hole (121) is inserted with the jig (340). Even in the configuration in which machining is performed, first, in the first machining step, the screw rotor base material (120) is machined with the spiral groove (41) and the reference surfaces (48a, 48b), and then the screw rotor By supporting the base material (120) again, machining the lower hole (121) with the reference surfaces (48a, 48b) as a reference, and finishing the hole (47) for inserting the shaft member, the lower Regardless of the shape accuracy of the hole (121) and the jig (340), the axial center of the spiral groove (41) and the axial center of the shaft member insertion hole (47) can be matched with high accuracy.

  According to the third aspect of the present invention, the spiral groove (41) and the reference surfaces (48a, 48b) are processed while the screw rotor base material (120) is rotatably supported around the predetermined rotation axis (A). Then, the shaft member (21) is inserted into the hole (47) of the screw rotor base material (120) and the screw rotor base material (120) is supported again with reference to the reference surfaces (48a, 48b). By processing the supported portions (21a, 21b) of the shaft member (21) with the reference surfaces (48a, 48b) as a reference in the re-supported state, the shaft center of the spiral groove (41) and the shaft member (21 ) With the axis of the supported portion (21a, 21b) with high accuracy. As a result, in the screw compressor (1), the axial displacement of the spiral groove (41) with respect to the rotation shaft of the screw rotor (40) can be suppressed, and the performance of the screw compressor (1) can be improved.

  According to the fourth invention, in a state where the screw rotor base material (120) is supported with reference to the reference surfaces (48a, 48b), the screw rotor base material (120) with reference to the reference surfaces (48a, 48b). By finishing the outer shape of the shaft, the shaft center of the outer shape of the screw rotor (40) is also the shaft center of the shaft member insertion hole (47) or the supported portion (21a, 21b) of the shaft member (21). It is possible to match with the axis of

  According to the fifth invention, the screw rotor (40) is provided at one end in the axial direction and is bent with respect to the bearing holder (60) when the screw rotor (40) is mounted on the screw compressor (1). By processing the reference surface (48a) in the small diameter part (46) that forms the gap, there is no need to provide a dedicated part for processing the reference surface (48a) in the screw rotor base material (120). The reference surface (48a) can be processed using (46).

  According to the sixth aspect of the invention, since the reference surface (48b) does not remain on the completed screw rotor (40) by providing a deletion step, the screw rotor (40) at the time of completion is not taken into consideration. The reference surface (48b) can be arbitrarily processed in consideration of only the above.

  According to the seventh invention, in the first machining step, the spiral groove (41) is first machined, and the reference surfaces (48a, 48b) are machined later, whereby the axial center of the spiral groove (41) The axis of the reference plane (48a, 48b) can be matched with higher accuracy.

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

Embodiment 1 of the Invention
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  A screw rotor (40) manufactured by a screw rotor manufacturing method according to an embodiment of the present invention is used for a single screw compressor (hereinafter simply referred to as a screw compressor) (1). First, the screw compressor (1) will be described.

  The screw compressor (1) is provided in a refrigerant circuit that performs a refrigeration cycle and compresses the refrigerant. As shown in FIGS. 2 and 3, the screw compressor (1) is configured in a hermetic type. In the screw compressor (1), the compression mechanism (20) and the electric motor (11) for driving the compression mechanism (20) are accommodated in one casing (10). The compression mechanism (20) is connected to the electric motor (11) via the drive shaft (21). Further, in the casing (10), a low-pressure gas refrigerant is introduced from the evaporator of the refrigerant circuit and the low-pressure space (S1) for guiding the low-pressure gas to the compression mechanism (20), and the compression mechanism (20) A high-pressure space (S2) into which the discharged high-pressure gas refrigerant flows is partitioned.

  The electric motor (11) includes a stator (12) and a rotor (13). The stator (12) is fixed to the inner peripheral surface of the casing (10) in the low-pressure space (S1). One end of a drive shaft (21) is connected to the rotor (13), and the drive shaft (21) is configured to rotate about the rotation axis (X) together with the rotor (13).

  The compression mechanism (20) includes a cylindrical wall (30) formed in the casing (10), a single screw rotor (40) disposed in the cylindrical wall (30), and the screw rotor (40). Two gate rotors (50) (not shown in FIG. 1).

  As shown in FIGS. 4 and 5, the screw rotor (40) is a metal member formed in a substantially cylindrical shape. The outer diameter of the screw rotor (40) is set slightly smaller than the inner diameter of the cylindrical wall (30), and the outer peripheral surface of the screw rotor (40) is in sliding contact with the inner peripheral surface of the cylindrical wall (30). Has been. A plurality (six in this embodiment) of spiral grooves (41) extending spirally from one axial end to the other end of the screw rotor (40) are formed on the outer periphery of the screw rotor (40). .

  Each of the plurality of spiral grooves (41) has a symmetric shape around the axial center of the cylindrical screw rotor (40) (that is, in the cross section of the screw rotor (40), Each has a point-symmetric shape with respect to the center of the screw rotor (40). The axis when the plurality of spiral grooves (41) are symmetric about a certain axis is referred to as the axis of the spiral groove (41). When the spiral groove (41) is accurately formed with respect to the screw rotor (40), the axis of the spiral groove (41) coincides with the axis of the screw rotor (40).

  Here, the taper surface (45) is formed in the peripheral part of the axial direction one end side of the screw rotor (40), and the one end part of the spiral groove (41) is opened to the taper surface (45). Each spiral groove (41) has one end portion (left end portion in FIG. 6) opening in the tapered surface (45) as a start end portion, and the other end portion (right end portion in FIG. 6) is a termination portion. On the other hand, the terminal end of the spiral groove (41) is open to the side circumferential surface at the other axial end of the screw rotor (40). In the spiral groove (41), of the side wall surfaces (42, 43) on both sides, the one located on the front side in the traveling direction of the gate (51) is the first side wall surface (42), and the traveling direction of the gate (51) What is located on the rear side is the second side wall surface (43).

  Moreover, the small diameter part (46) whose outer diameter is smaller than the main-body part (40a) in which the spiral groove (41) is formed is formed in the other end part of the screw rotor (40).

  Furthermore, as shown in FIG. 1, the screw rotor (40) is formed with an insertion hole (47) through which the drive shaft (21) is inserted, through the axial center of the screw rotor (40). . This insertion hole (47) constitutes a hole.

  The drive shaft (21) is inserted through the screw rotor (40) configured as described above. Specifically, as described above, the rotor (13) of the electric motor (11) is connected to one end of the drive shaft (21), and the other end of the drive shaft (21) is connected to the screw rotor (40). Is inserted into the insertion hole (47). The screw rotor (40) and the drive shaft (21) are connected by a key (22). The drive shaft (21) is arranged coaxially with the screw rotor (40).

  Thus, the screw rotor (40) and the rotor (13) of the electric motor (11) are accommodated in the casing (10) in a state of being connected to the drive shaft (21). At this time, the screw rotor (40) is rotatably fitted to the cylindrical wall (30), and the outer peripheral surface thereof is in sliding contact with the inner peripheral surface of the cylindrical wall (30).

  Here, a first supported portion (21a) projecting from the rotor (13) is formed at one end of the drive shaft (21), and this first supported portion (21a) is formed on the roller bearing (14). It is supported rotatably. On the other hand, a second supported portion (21b) protruding from the screw rotor (40) is formed at the other end portion of the drive shaft (21), and this second supported portion (21b) is a compression mechanism (20). Is supported rotatably on a ball bearing (61) located on the high-pressure side.

  The ball bearing (61) is installed in a bearing holder (60) fitted to the cylindrical wall (30) of the casing (10). An annular wall portion (62) protruding toward the screw rotor (40) is provided at the peripheral edge of the end surface of the bearing holder (60) on the screw rotor (40) side.

  When the screw rotor (40) is disposed in the cylindrical wall (30), the annular wall portion (62) is formed so that the small diameter portion (46) of the screw rotor (40) is within the annular wall portion (62). It is configured to enter the circumferential side. At this time, a slight gap is formed between the small diameter portion (46) and the annular wall portion (62), and the small diameter portion (46) of the screw rotor (40) and the annular wall portion of the bearing holder (60). (62) is not in radial or axial contact. That is, between the small diameter portion (46) and the annular wall portion (62), after entering the radially inward from the outer peripheral surface of the screw rotor (40), it is bent in the axial direction and then further radially inward. In other words, a gap having a shape in which the longitudinal section is bent in a crank shape is formed.

  Each gate rotor (50) is a resin member in which a plurality (11 in this embodiment) of gates (51) formed in a rectangular plate shape are provided radially. 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). Each gate rotor (50) is arranged so that the gate (51) penetrates a part of the cylindrical wall (30) and meshes with the spiral groove (41) of the screw rotor (40).

  The gate rotor (50) is attached to a metal rotor support member (55) (see FIG. 5). The rotor support member (55) includes a base portion (56), an arm portion (57), and a shaft portion (58). The base (56) is formed in a slightly thick disk shape. The same number of arms (57) as the gates (51) of the gate rotor (50) are provided and extend radially outward from the outer peripheral surface of the base (56). The shaft portion (58) is formed in a rod shape and is erected on the base portion (56). The central axis of the shaft portion (58) coincides with the central axis of the base portion (56). The gate rotor (50) is attached to a surface of the base portion (56) and the arm portion (57) opposite to the shaft portion (58). Each arm part (57) is in contact with the back surface of the gate (51).

  The rotor support member (55) to which the gate rotor (50) is attached is accommodated in a gate rotor chamber (90) defined in the casing (10) adjacent to the cylindrical wall (30) (FIG. 3). See). The rotor support member (55) disposed on the right side of the screw rotor (40) in FIG. 3 is installed in such a posture that the gate rotor (50) is on the lower end side. On the other hand, the rotor support member (55) disposed on the left side of the screw rotor (40) in the figure is installed in such a posture that the gate rotor (50) is on the upper end side. The shaft portion (58) of each rotor support member (55) is rotatably supported by a bearing housing (91) in the gate rotor chamber (90) via ball bearings (92, 93). 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 spiral groove (41) of the screw rotor (40), and the gate (51) of the gate rotor (50) is compressed. (23) The spiral 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 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).

  Although not shown, the slide valve (70) has a discharge port for communicating the compression chamber (23) and the high-pressure space (S2). That is, the refrigerant compressed in the compression chamber (23) is discharged from the discharge port of the slide valve (70) to the high pressure space (S2). The cylindrical wall (30) has an upstream end of a bypass passage for returning the refrigerant from the compression chamber (23) to the low pressure space (S1), and the slide valve (70) is an upstream end of the bypass passage. Open and close to adjust the capacity of the compression mechanism (20).

-Driving action-
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. Here, the description will be given focusing on the compression chamber (23) shaded in FIG.

  In FIG. 6 (A), the compression chamber (23) with shading communicates with the low-pressure space (S1). Further, the spiral groove (41) in which the compression chamber (23) is formed meshes with the gate (51) of the gate rotor (50) located on the lower side of the figure. When the screw rotor (40) rotates, the gate (51) relatively moves toward the terminal end of the spiral groove (41), and the volume of the compression chamber (23) increases accordingly. As a result, the low-pressure gas refrigerant in the low-pressure space (S1) is sucked into the compression chamber (23) through the suction port (24).

  When the screw rotor (40) further rotates, the state shown in FIG. 6 (B) is obtained. In the figure, the compression chamber (23) with shading is completely closed. That is, the spiral groove (41) in which the compression chamber (23) is formed meshes with the gate (51) of the gate rotor (50) located on the upper side of the figure, and the low pressure space ( It is partitioned from S1). When the gate (51) moves toward the end of the spiral groove (41) as the screw rotor (40) rotates, the volume of the compression chamber (23) gradually decreases. As a result, the gas refrigerant in the compression chamber (23) is compressed.

  When the screw rotor (40) further rotates, the state shown in FIG. In the figure, the shaded compression chamber (23) is in communication with the high-pressure space (S2) via a discharge port (not shown). When the gate (51) moves toward the end of the spiral groove (41) as the screw rotor (40) rotates, the compressed refrigerant gas is pushed out from the compression chamber (23) to the high-pressure space (S2). Go.

  When the compression chamber (23) is completely closed, the gate (51) and the wall surface (42, 43, 44) of the spiral groove (41) do not have to physically rub against each other. There is no problem even if there are minute gaps between them. In other words, even if there is a minute gap between the gate (51) and the wall surface (42, 43, 44) of the spiral groove (41), if this gap can be sealed with an oil film made of lubricating oil, The air tightness of the compression chamber (23) is maintained, and the amount of gas refrigerant leaking from the compression chamber (23) is suppressed to a small amount.

-Screw rotor processing equipment-
Subsequently, a screw rotor processing apparatus (hereinafter simply referred to as a processing apparatus) (100) of the present embodiment will be described. This processing apparatus (100) is used in a first processing step described later.

  As shown in FIGS. 7 and 8, the machining apparatus (100) includes a tool support unit (200) that supports a tool (110) such as an end mill, and a mother that supports a screw rotor base material (120) that is a workpiece. A material support unit (300) and a base (130) on which the tool support unit (200) and the base material support unit (300) are disposed are provided.

  The tool support unit (200) includes a column (210) disposed on the base (130) and a spindle part (220) attached to the column (210).

  The column (210) is slidably attached to a Z-axis guide rail (140, 140) provided on the upper surface of the base (130), and extends in the Z-axis direction in which the Z-axis guide rail (140, 140) extends. It is movable. A Y-axis guide rail (150, 150) extending along the Y-axis extends on the surface of the column (210) facing the base material support unit (300). The Y axis extends in the vertical direction.

  The spindle section (220) has a main shaft (230) to which a tool (110) such as an end mill is attached. The main shaft (230) is attached to the base portion (240) slidably attached to the Y-axis guide rails (150, 150) of the column (210) so that the rotation shaft extends in the Z-axis direction. ing. That is, the spindle portion (220) is movable in the Y-axis direction in which the Y-axis guide rail (150, 150) extends, and the tool (110) is rotated around the rotation axis extending in parallel with the Z-axis guide rail (140, 140). To rotate.

  The tool support unit (200) thus configured supports the tool (110) by the spindle portion (220) and rotationally drives it, and translates the tool (110) along the Y axis and the Z axis. .

  On the other hand, the base material support unit (300) includes a rotary table (310) that is rotatably arranged with respect to the base (130), and a screw that is a work piece that is installed on the rotary table (310). A clamp part (320) for clamping the rotor base material (120), and a rotation center of the screw rotor base material (120) installed on the rotary table (310) and supported by the clamp part (320). And a center push stand (330). This base material support unit (300) constitutes a base material support.

  The rotary table (310) is slidably attached to an X-axis guide rail (160, 160) provided on the upper surface of the base (130) and extending in the X-axis direction (perpendicular to the Y-axis and Z-axis). It has a base part (311) and a turntable (312) attached to be rotatable about a vertical axis (B) extending in the vertical direction with respect to the base part (311). That is, the rotary table (310) is configured to be movable in the X-axis direction via the base portion (311), and is configured to be rotatable around the vertical axis (B) via the rotary table (312). ing.

  The clamp part (320) rotatably supports the screw rotor base material (120) around a horizontal axis (A) extending in the horizontal direction. Specifically, as shown in FIG. 9, the clamp (320) is provided with a shaft-shaped jig (340) that rotates around the horizontal axis (A) about the axis. The screw rotor base material (120) is attached to the jig (340) from the tip side so that the pilot hole (121) of the screw rotor base material (120) is inserted into the jig (340). The Then, the screw rotor base material (120) is fixed to the jig (340) by fastening the nut (360) through the spacer (350) from the tip side of the jig (340). The jig (340) can be removed from the clamp part (320), and can be replaced in accordance with the diameter of the prepared hole of the screw rotor base material (120) to be processed, the axial length, or the like. The horizontal axis (A) intersects the vertical axis (B) that is the rotation center of the turntable (312).

  The center pusher (330) is disposed on the rotary table (310), and the center (331) is configured to be able to advance and retract along the horizontal axis (A). The center of the center (331) coincides with the horizontal axis (A) of the clamp part (320), and is provided rotatably on the clamp part (320) when advanced to the clamp part (320) side. It is comprised so that it may contact | abut from the front end side of this jig | tool (340) with respect to the rotation center of a jig | tool (340). That is, the center push stand (330) is horizontally pushed by the clamp portion (320) by pushing the center of rotation at the free end of the jig (340) supported in a cantilevered manner by the clamp portion (320). The jig (340) that is driven to rotate around the axis (A), and thus the shaft rotor of the screw rotor base material (120) is prevented.

  That is, the base material support unit (300) translates the screw rotor base material (120) clamped by the clamp portion (320) along the X axis, and around the horizontal axis (A) and the vertical axis (B). Rotate.

  Here, the base material support unit (300) is configured such that the vertical axis (B) passes through the center of gravity of the turntable (312) including the clamp portion (320) and the center push stand (330). By doing this, the moment of inertia around the vertical axis (B) of the turntable (312) is reduced, so the drive torque and braking torque of the turntable (312) are reduced, and the screw rotor base material (120) is moved to the vertical axis. (B) It becomes easy to rotate around. Further, since the centrifugal force when rotating the turntable (312) is reduced, the screw rotor base material (120) can be easily rotated around the vertical axis (B) also in this respect.

  Furthermore, the base material support unit (300) is configured so that the vertical axis (B) passes through the screw rotor base material (120) clamped by the clamp portion (320). In other words, the screw rotor base material (120) is attached to the clamp part (320) so as to be positioned on the vertical axis (B). In this way, when the screw rotor base material (120) is rotated to change the posture of the screw rotor base material (120), the screw rotor base material (120) and the tool (110) before and after the rotation. The relative position of the tool (110) is relatively moved in accordance with the rotated screw rotor base material (120) (the tool support unit (200) is moved in the Y-axis and Z-axis directions). And the amount by which the rotary table (310) is moved in the X-axis direction) can be suppressed.

  In the base material support unit (300), a rotary table (310) that can rotate about the vertical axis (B) is first disposed on the base (130), and the screw rotor base material (120) is placed horizontally. Even if the rotary table (310) is rotated around the vertical axis (B) by arranging the clamp part (320) supported rotatably around the axis (A) on the rotary table (310), the screw The orientation of the rotor base material (120) is such that its axis (the axis of the screw rotor (40)) remains in the horizontal direction, and the screw rotor base material (120) is moved to the horizontal axis (A) by the clamp part (320). Of course, even if it is rotated around, the orientation of the screw rotor base material (120) remains the horizontal direction (the axis of the screw rotor (40)), so the clamp part (320) and the rotary table ( 310) the weight of screw rotor base material (120) to Of impact does not change. As a result, the screw rotor base material (120) can be rotated and moved without considering the influence of the gravity of the screw rotor base material (120), and the posture and position of the screw rotor base material (120) can be increased. The accuracy can be controlled.

  The machining apparatus (100) configured in this manner drives the tool support unit (200) and the base material support unit (300) in accordance with a control signal from a control unit (not shown), thereby FIG. As shown, the tool (110) and the screw rotor base material (120) are relatively moved, and the screw rotor base material (120) is processed by the tool (110). The machining apparatus (100) moves the tool (110) and the screw rotor base material (120) relatively straight along the three axes (X axis, Y axis, and Z axis) as described above, and 2 By rotating relative to the axis (horizontal axis (A) and vertical axis (B)), as described above, even complex shapes such as spiral grooves (41) can be processed. Can do.

  Hereinafter, the manufacturing method of a screw rotor (40) is demonstrated.

  As shown in FIG. 1A, the screw rotor base material (120) is a metal member formed in a substantially columnar shape. The outer diameter is slightly larger than the outer diameter of the finished screw rotor (40). Further, the screw rotor base material (120) is formed with a tapered surface (45) and a small diameter portion (46). Further, a reference step (49) for forming a second reference surface (48b) to be described later is formed at the end of the screw rotor base material (120) opposite to the small diameter portion (46). Yes. Furthermore, the screw rotor base material (120) has a through hole (47) through which the drive shaft (21) is inserted, and a through hole (121) passes through the axis of the screw rotor base material (120). Is formed. In the lower hole (121), a key groove (122) into which a key (22) for connecting the screw rotor (40) and the drive shaft (21) is fitted is formed along the axial direction.

  The screw rotor base material (120) configured in this way includes a supporting step of rotatably supporting the screw rotor base material (120) by the processing device (100), and a spiral groove ( 41) a first machining step for performing a grooving step, etc., a re-supporting step for re-supporting the screw rotor base material (120) with a lathe, and an insertion hole (47) in the screw rotor base material (120). A screw rotor (40) as a finished product shown in FIG. 1 (C) after a second machining step for performing a hole machining step and the like, and a deletion process for removing unnecessary portions of the screw rotor base material (120). To be processed.

  First, the screw rotor base material (120) is attached to the processing device (100) in the supporting step. Specifically, as shown in FIG. 9, the screw rotor base material (120) is mounted from the front end side of the jig (340) so that the lower hole (121) is inserted through the jig (340). Then, the screw rotor base material (120) is fixed to the jig (340) by fastening the nut (360) through the spacer (350) from the tip side of the jig (340). Thereafter, the center (331) of the center push stand (330) is advanced, and the jig (340) is center-pressed from the tip side. Thus, the screw rotor base material (120) is rotatably supported around the horizontal axis (A) of the clamp part (320) in the supporting step.

  Next, in the first processing step, as shown in FIG. 10, the spiral groove (41) is processed in the screw rotor base material (120) by the processing device (100).

  Specifically, the machining device (100) moves the tool (110) relative to the screw rotor base material (120) based on a tool path given in advance as numerical data, thereby causing the spiral groove (41) to move. Is processed. The machining apparatus (100) sequentially performs a plurality of steps from roughing to finishing using a plurality of types of tools (110). For example, the processing apparatus (100) uses an end mill as a tool (110) to rough-cut the lower groove of the spiral groove (41) on the screw rotor base material (120). Thereafter, the first side wall surface (42) of the spiral groove (41) is processed by the end mill (110), and then the second side wall surface (43) of the spiral groove (41) is processed by the end mill (110), Finish the spiral groove (41).

  Subsequently, without changing the support state of the screw rotor base material (120) to the support state when the spiral groove (41) is processed, the screw rotor base material (120) is provided with the first reference surface (48a) and the second reference surface. Process the surface (48b).

  Specifically, as shown in FIG. 11, the first reference surface (48a) is processed into the small diameter portion (46) of the screw rotor base material (120) with a tool (110) such as an end mill. Similarly, as shown in FIG. 12, the second reference surface (48b) is processed on the reference step (49) of the screw rotor base material (120) with a tool (110) such as an end mill. That is, the first reference surface (48a) and the second reference surface (48b) are cylindrical surfaces having the horizontal axis (A) as an axis.

  Thus, in the first processing step, as shown in FIG. 1 (B), the screw rotor base material (120) is provided with the spiral groove (41), the first reference surface (48a), and the second reference surface (48b). Is processed.

  Thereafter, in the re-supporting step, the screw rotor base material (120) is removed from the processing apparatus (100) and attached to the lathe (400).

  Specifically, as shown in FIG. 13, the lathe (400) includes a tool support unit (420) that supports a tool (410) such as a tool, and a mother that supports a screw rotor base material (120) that is a workpiece. A material support unit (430), a center press stand (440) that abuts against the rotation center of the screw rotor base material (120) supported by the base material support unit (430) and presses the center, and these tool support units (420) ), A base material support unit (430), and a base (450) on which a center push stand (440) is disposed. The base material support unit (430) includes a chuck portion (431) that grips the screw rotor base material (120), and the screw rotor base material (120) gripped by the chuck portion (431) C) Drive around. The tool support unit (420) can move the supported tool (410) on the base (450) in the three axis directions along the rotation axis (C), the vertical direction, and the directions perpendicular to both directions. It is configured. The center push stand (440) has a center (441) protruding toward the base material support unit (430). The tip of the center (441) is located on the rotating shaft (C) and is mounted on the center pusher (440) so as to be able to advance and retract along the rotating shaft (C).

  In the re-supporting step, as shown in FIG. 14, the first reference surface (48a) of the screw rotor base material (120) is gripped by the chuck portion (431) of the lathe (400). At this time, the screw rotor base material (120) is centered on the basis of the second reference surface (48b). That is, with reference to the second reference surface (48b), adjustment is made so that the axis of the second reference surface (48b) coincides with the rotation axis (C) of the lathe (400). For example, the axial center of the second reference surface (48b) may vary depending on the value of the dial gauge when the chuck portion (431) is manually rotated while the dial gauge is in contact with the second reference surface (48b). It is possible to measure how much the rotation axis (C) of the lathe (400) matches. Thus, in the re-supporting step, the screw rotor base material (120) is supported so as to rotate around the rotation axis (C) of the lathe (400) around the axis of the second reference surface (48b).

  Next, in the second processing step, finishing of the insertion hole (47) of the screw rotor base material (120) is performed. Specifically, as shown in FIG. 13, the through hole (47) is finished by cutting the lower hole (121) of the screw rotor base material (120) with a cutting tool (410).

  In the second processing step, the outer shape of the screw rotor base material (120) is also finished. That is, the outer diameter of the screw rotor base material (120) is slightly larger than the outer diameter of the screw rotor (40) as a finished product. Cut with a tool (410) so that the outer diameter is in sliding contact with the inner peripheral surface of 10).

  Then, after the second processing step, in the deletion step, the reference step portion (49) of the screw rotor base material (120) is deleted by cutting. Specifically, the reference step (49) of the screw rotor base material (120) is deleted by cutting with a cutting tool (410).

  Thus, the screw rotor base material (120) is processed to produce the screw rotor (40).

  Finally, the drive shaft (21) is shrink-fitted into the insertion hole (47) of the completed screw rotor (40), and the screw rotor (40) and the drive shaft (21) are assembled into the casing (10). Assemble the screw compressor (1).

  According to this manufacturing method, the spiral groove (41) and the first and second reference surfaces (48a, 48b) are processed in the screw rotor base material (120) in the first processing step. At this time, the screw rotor base material (120) remains rotatably supported by the jig (340) of the processing device (100) around the horizontal axis (A). That is, the spiral groove (41) and the first and second reference surfaces (48a, 48b) are processed with the horizontal axis (A) as a reference, that is, with the horizontal axis (A) as an axis. That is, the axial center of the spiral groove (41) and the axial center of the first and second reference surfaces (48a, 48b) coincide with each other.

  Thereafter, in the re-supporting step, the screw rotor base material (120) is supported again on the lathe (400) on the basis of the second reference surface (48b). That is, the screw rotor base material (120) is supported so that the axis of the second reference surface (48b) coincides with the rotation axis (C) of the lathe (400). By doing so, the screw rotor base material (120) is supported so that the axis of the spiral groove (41) coincides with the rotational axis (C) of the lathe (400).

  In the second machining step, the insertion hole (47) is machined with a lathe (400). As a result, of course, the axis of the insertion hole (47) coincides with the rotational axis (C) of the lathe (400). At this time, since the axis of the spiral groove (41) also coincides with the rotation axis (C), the axis of the insertion hole (47) coincides with the axis of the spiral groove (41) with high accuracy. It will be.

  Therefore, according to the present embodiment, the screw rotor base material (120) is provided with the spiral groove (41) and the first and second reference surfaces (48a, 48b) in the same supporting state (that is, around the rotation axis (A)). The screw rotor base material (120) is re-supported so as to rotate about the axis of the second reference surface (48b), and the support state is By machining the insertion hole (47) in the screw rotor base material (120), the axis of the spiral groove (41) and the axis of the insertion hole (47) can be made to coincide with each other with high accuracy.

  In the screw compressor (1) equipped with the screw rotor (40) thus manufactured, the screw rotor (40) rotates around the axis of the spiral groove (41), that is, the spiral groove. The eccentricity of (41) can be suppressed and the gap distribution between the gate (51) of the gate rotor (50) and the spiral groove (41) can be made uniform. As a result, it is possible to prevent the gap from becoming larger during the compression and the refrigerant from leaking, or conversely the gap from becoming smaller and the gate (51) and the spiral groove (41) from interfering with each other. The performance of (1) can be improved.

  Further, the tool (110) and the screw rotor base material (120) are moved relatively straight along the three axes (X axis, Y axis and Z axis), and two axes (horizontal axis (A) and vertical axis). (B)) By using the processing device (100) that relatively rotates around the spiral groove (41) and the first and second reference planes to the screw rotor base material (120) in the same supporting state. Processing with (48a, 48b) can be easily realized.

  Further, in the first processing step, the spiral groove (41) is first processed in the screw rotor base material (120), and the first and second reference surfaces (48a, 48b) are processed later, thereby forming the spiral groove. The axis of (41) and the axes of the first and second reference planes (48a, 48b) can be matched with high accuracy. That is, the screw rotor base material (120) is processed during the processing of the spiral groove (41) because the screw rotor base material (120) is heavy and has a large cutting resistance in the early stage when the spiral groove (41) is processed. May shift with respect to the horizontal axis (A). However, in the final stage when processing the spiral groove (41), the screw rotor base material (120) is also relatively light in weight, and the cutting amount is reduced and the cutting resistance is reduced in the finishing stage. The possibility of the screw rotor base material (120) shifting with respect to the horizontal axis (A) during the processing of 41) is reduced. That is, if the spiral groove (41) is processed after the first and second reference surfaces (48a, 48b) are processed in the screw rotor base material (120), the screw rotor base material ( 120) is displaced with respect to the horizontal axis (A), and the axis of the already processed first and second reference surfaces (48a, 48b) and the axis of the processed spiral groove (41) are misaligned. There is a fear. Therefore, after processing the spiral groove (41) in the screw rotor base material (120), by processing the first and second reference surfaces (48a, 48b), the axial center of the spiral groove (41) and the first and second The axis of the second reference plane (48a, 48b) can be matched with high accuracy.

  Further, in the second processing step, not only the insertion hole (47) of the screw rotor base material (120) is finished, but also the outer shape of the screw rotor base material (120) is finished, thereby inserting the insertion hole. The shaft center of (47) and the shaft center of the outer peripheral shape of the screw rotor base material (120) can be matched with high accuracy. As a result, in the screw compressor (1) equipped with the screw rotor (40) thus processed, the gap between the outer peripheral surface of the screw rotor (40) and the inner peripheral surface of the cylindrical wall (30) of the casing (10). The distribution can be made uniform. That is, it is possible to prevent the gap from becoming large during the compression and the refrigerant from leaking, and conversely, the gap from becoming small and preventing the screw rotor (40) and the cylindrical wall (30) from interfering with each other. The performance of (1) can be improved.

  In addition, in the deletion step, the reference step (49) for processing the second reference surface (48b) is finally scraped off so that the screw rotor (40) as a finished product is obtained. Without considering, it is sufficient to provide the reference step (49) considering only the ease of processing the second reference surface (48b) and the ease of making the screw rotor base material (120). And productivity can be improved.

  Furthermore, in the above-described embodiment, the axis of the first reference surface (48a) gripped by the chuck portion (431) of the lathe (400) is similar to the axis of the second reference surface (48b) of the spiral groove (41). By matching the first reference surface (48a) with high accuracy with respect to the shaft center, the shaft center of the spiral groove (41) can be turned into the rotation axis ( C) almost coincides with the second reference surface (48b), so that the adjustment amount for aligning the axis of the second reference surface (48b) with the rotation axis (C) of the lathe (400) can be reduced. The axis of (48b) and the rotation axis (C) of the lathe (400) can be easily matched.

  Furthermore, the annular wall portion (62) of the bearing holder (60) is fitted into the first reference surface (48a) which serves as a reference when supporting the screw rotor base material (120), and the annular wall portion (62). Since the first reference surface (48a) can be processed in a portion necessary for the screw rotor (40) as a finished product by processing into a small diameter portion (46) that forms a gap bent between It is not necessary to separately provide a portion for processing the first reference surface (48a), and further, by processing the cylindrical surface of the small diameter portion (46) as the first reference surface (48a), the small diameter portion (46). The shape accuracy can be improved.

  In the above-described embodiment, the first reference surface (48a) is gripped by the chuck portion (431) and the support state is adjusted based on the second reference surface (48b). (48b) may be gripped by the chuck portion (431), and the support state may be adjusted based on the first reference surface (48a). Further, only one of the first and second reference surfaces (48a, 48b) is provided, and the one reference surface is gripped by the chuck portion (431), and the chuck portion (431) of the reference surface is provided. You may adjust a support state on the basis of the part which protrudes. Further, a portion other than the first and second reference surfaces (48a, 48b) is gripped by the chuck portion (431), and the support state is adjusted based on the first or second reference surface (48a, 48b). There may be.

<< Embodiment 2 of the Invention >>
Then, the screw rotor manufacturing method which concerns on Embodiment 2 of this invention is demonstrated.

  The screw rotor manufacturing method according to the second embodiment is different from the first embodiment in the re-supporting step and the second processing step. Therefore, the same components as those of the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  In the screw rotor manufacturing method according to the second embodiment, the screw rotor (40) is manufactured by processing the screw rotor base material (120) with the processing device (100) and the lathe (400), as in the first embodiment.

  Unlike the screw rotor base material (120) according to the first embodiment, the screw rotor base material (120) used in the screw rotor manufacturing method according to the second embodiment is not provided with the reference step (49), An insertion hole (47) for allowing the drive shaft (21) to pass therethrough is formed in advance in the shaft center of the screw rotor base material (120).

  The screw rotor base material (120) configured in this way includes a supporting step of rotatably supporting the screw rotor base material (120) by the processing device (100), and a spiral groove ( 41) The first machining process to machine etc., the re-support process to re-support the screw rotor base material (120) with the lathe (400), and the processing of the insertion hole (47) etc. in the screw rotor base material (120) The screw rotor (40) as a finished product is processed through the second processing step to be performed.

  Here, the support process is the same as that of the first embodiment, and thus the description thereof is omitted.

  In the screw rotor manufacturing method according to Embodiment 2, in the first processing step, the spiral groove (41) is processed in the screw rotor base material (120), and then the first reference surface (48a) is processed. That is, the processing of the spiral groove (41) and the first reference surface (48a) is the same as in Embodiment 1, but the second reference surface (48b) is not processed in the first processing step according to Embodiment 2.

  In the re-supporting step, first, the screw rotor base material (120) is removed from the processing apparatus (100), and the drive shaft (21) is shrink-fitted into the insertion hole (47) of the screw rotor base material (120). Then, the screw rotor base material (120) with the drive shaft (21) attached is attached to the lathe (400). Specifically, as shown in FIG. 15, a center support jig (432) is separately attached to the base material support unit (430), and one end of the drive shaft (21) is supported by the center support jig (432). On the other hand, the other end of the drive shaft (21) is supported by the center (441) of the center push stand (440). That is, the drive shaft (21) is supported in a state where both centers are pushed. At this time, with reference to the first reference surface (48a), the screw rotor base material is adjusted so that the axis of the first reference surface (48a) coincides with the rotational axis (C) of the lathe (400). (120) is mounted on the lathe (400).

  Thus, in the re-supporting step, the screw rotor base material (120) is supported so as to rotate around the rotational axis (C) of the lathe (400) around the axis of the first reference surface (48a).

  Next, in the second processing step, finishing of the drive shaft (21) of the screw rotor base material (120) is performed. Specifically, the first and second supported portions (21a, 21b) supported by the roller bearing (14) and the ball bearing (61) of the drive shaft (21) are finished. In the drive shaft (21) before processing, the outer diameters of the first and second supported parts (21a, 21b) are slightly larger than the outer diameters suitable for the roller bearing (14) and the ball bearing (61), respectively. The first and second supported portions (21a, 21b) are finished with a lathe (400) so that the first and second supported portions (21a, 21b) are respectively roller bearings. (14) and ball bearing (61).

  Thus, the axial centers of the finished first and second supported parts (21a, 21b) coincide with the rotational axis (C) of the lathe (400). In addition, due to the mounting of the screw rotor base material (120) to the lathe (400) in the re-supporting step, the axis of the first reference surface (48a) also coincides with the rotational axis (C) of the lathe (400). Furthermore, the axial center of the first reference surface (48a) also coincides with the axial center of the spiral groove (41) processed under the same supporting state in the first processing step. That is, the axial centers of the first and second supported parts (21a, 21b) coincide with the axial center of the spiral groove (41) with high accuracy.

  Further, in the second processing step, the outer shape of the screw rotor base material (120) is also finished. That is, the outer diameter of the screw rotor base material (120) is slightly larger than the outer diameter of the screw rotor (40) as a finished product. Process the outer diameter so as to be in sliding contact with the inner peripheral surface of 10).

  Thus, the screw rotor base material (120) is processed to produce the screw rotor (40).

  Finally, the completed screw rotor (40) is assembled into the casing (10) to assemble the screw compressor (1).

  According to this manufacturing method, the spiral groove (41) and the first reference surface (48a) are processed in the screw rotor base material (120) in the first processing step. At this time, the screw rotor base material (120) remains rotatably supported by the jig (340) of the processing device (100) around the horizontal axis (A). That is, the spiral groove (41) and the first reference surface (48a) are processed with the horizontal axis (A) as a reference, that is, with the horizontal axis (A) as an axis. That is, the axis of the spiral groove (41) and the axis of the first reference surface (48a) coincide.

  Thereafter, in the re-supporting step, the drive shaft (21) is inserted through the screw rotor base material (120), and the lathe (400) is turned on the screw rotor base material (120) with reference to the first reference surface (48a). Support again. That is, the screw rotor base material (120) is supported so that the axis of the first reference surface (48a) coincides with the rotation axis (C) of the lathe (400). By doing so, the screw rotor base material (120) is supported so that the axis of the spiral groove (41) coincides with the rotational axis (C) of the lathe (400).

  In the second machining step, the first and second supported parts (21a, 21b) of the drive shaft (21) are machined by a lathe (400). As a result, as a matter of course, the axial centers of the first and second supported parts (21a, 21b) coincide with the rotational axis (C) of the lathe (400). At this time, since the axial center of the spiral groove (41) also coincides with the rotational axis (C), the axial center of the first and second supported portions (21a, 21b) is the same as that of the spiral groove (41). It matches the shaft center with high accuracy.

  Therefore, according to the present embodiment, the spiral groove (41) and the first reference surface (48a) are supported on the screw rotor base material (120) in the same supporting state (that is, rotatable around the rotation axis (A)). The screw rotor base material (120) is then re-supported so as to rotate about the axis of the first reference surface (48a), and the drive shaft (21) is supported in the supported state. By machining the first and second supported parts (21a, 21b), the axis of the spiral groove (41) and the axis of the first and second supported parts (21a, 21b) are matched with high accuracy. Can be made.

  In the screw compressor (1) equipped with the screw rotor (40) manufactured in this way, the screw rotor (40) rotates around the axis of the spiral groove (41), that is, the spiral groove (41 ) Can be suppressed and the gap distribution between the gate (51) of the gate rotor (50) and the spiral groove (41) can be made uniform. As a result, it is possible to prevent the gap from becoming larger during the compression and the refrigerant from leaking, or conversely the gap from becoming smaller and the gate (51) and the spiral groove (41) from interfering with each other. The performance of (1) can be improved.

  In the present embodiment, the first and second supported shafts (21) are finally supported by the roller bearing (14) and the ball bearing (61) so as to be freely rotatable in the screw compressor (1). The shaft of the screw rotor (40) and the axis of the spiral groove (41) in the screw compressor (1) are made to coincide with the axis of the spiral groove (41) with high accuracy by aligning the axis of the part (21a, 21b) The mind can be matched with higher accuracy. In other words, even if there is a shape error of the insertion hole (47) formed in the screw rotor base material (120), a shape error of the drive shaft (21), or an installation error of the drive shaft (21), all these errors are eliminated. In order to process the first and second supported parts (21a, 21b) with respect to the drive shaft (21) in a state in which the axis is aligned with the axis of the spiral groove (41), After absorbing all the errors, the axis of the spiral groove (41) and the axes of the first and second supported parts (21a, 21b) of the drive shaft (21) can be made to coincide with each other with high accuracy.

  In addition, in the second embodiment, the same operations and effects as those of the first embodiment can be achieved with respect to the same configuration as that of the first embodiment.

  In the second embodiment, only the first reference surface (48a) is processed as the reference surface on the screw rotor base material (120). However, the present invention is not limited to this. Similarly to the first embodiment, a reference step (49) may be provided, and the second reference surface (48b) may be further processed on the reference step (49), or the first reference surface (48a) Instead, only the second reference surface (48b) may be processed. However, as described above, when the first reference surface (48a) is processed into the small diameter portion (46) of the screw rotor (40), the first reference surface ( 48a) can be processed, it is not necessary to separately provide a portion for processing the first reference surface (48a), the screw rotor base material (120) can be simplified, and the screw rotor (40 ) Can also be simplified. On the other hand, in the configuration in which the reference step portion (49) is provided in the screw rotor base material (120) and the second reference surface (48b) is processed in the reference step portion (49), after the second processing step. Finally, by cutting off the reference step (49) together with the second reference surface (48b), the reference step (49) does not consider the screw rotor (40) as a finished product. Since it is only necessary to consider the ease of processing the second reference surface (48b) and the ease of making the screw rotor base material (120), workability and productivity can be improved.

<< Other Embodiments >>
The present invention may be configured as follows with respect to the embodiment.

  That is, in the said embodiment, although the screw rotor base material (120) is processed using the processing apparatus (100) and the lathe (400), it is not restricted to this. For example, in the first embodiment, a boring apparatus may be used instead of the lathe (400), and in the second embodiment, a grinding machine may be used instead of the lathe (400).

  Further, the first and second reference surfaces (48a, 48b) are not limited to the above-described embodiment, and may be processed at an arbitrary place.

  Further, the finishing process of the outer peripheral shape of the screw rotor base material (120) may be performed in the first processing step under the same supporting state as the processing of the spiral groove (41) and the reference surfaces (48a, 48b).

  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 screw rotor manufacturing method for manufacturing a screw rotor that is attached to a shaft member and supported rotatably in a screw compressor by processing the screw rotor base material.

It is a longitudinal cross-sectional view of the screw rotor base material and screw rotor which concern on embodiment of this invention, Comprising: (A) is a screw rotor base material before a 1st process process, (B) is a screw rotor after a 1st process process. A base material, (C) shows a screw rotor. It is a longitudinal cross-sectional view of a screw compressor. It is a cross-sectional view of a screw compressor. It is a perspective view which extracts and shows the principal part of a single screw compressor. It is the perspective view seen from another angle which extracted and shows the principal part of a single screw compressor. It is a top view which shows operation | movement of a compression mechanism, (A) shows a suction stroke, (B) shows a compression stroke, (C) shows a discharge stroke. It is a perspective view which shows the whole structure of a screw rotor processing apparatus. It is a perspective view which shows the screw rotor processing apparatus at the time of a process. It is a partial cross section figure which shows the support state of the screw rotor base material in a screw rotor processing apparatus. In a screw rotor processing apparatus, it is a perspective view which shows a state when processing a spiral groove in a screw rotor base material. It is a perspective view which shows a state when processing a 1st reference surface in a screw rotor base material in a screw rotor processing apparatus. In a screw rotor processing apparatus, it is a perspective view which shows a state when processing a 2nd reference surface to a screw rotor base material. It is a front view which shows schematic structure of a lathe. It is an enlarged view of the chuck | zipper part which shows the support state of the screw rotor base material in a lathe. It is a top view of the lathe which shows the mode in the re-supporting process of the manufacturing method of the screw rotor which concerns on Embodiment 2, and a 2nd process process.

Explanation of symbols

A Horizontal axis (rotary axis)
1 Screw compressor
14 Roller bearing (bearing)
21 Drive shaft member
21a First supported part (supported part)
21b Second supported part (supported part)
40 screw rotor
40a Body
41 Spiral groove
46 Small diameter part
47 Insertion hole (hole)
48a First reference plane (reference plane)
48b Second reference plane (reference plane)
60 Bearing holder
61 Ball bearing
120 Screw rotor base material
121 pilot hole
340 Jig

Claims (7)

A screw rotor manufacturing method for manufacturing a screw rotor (40) attached to a shaft member (21) and rotatably supported in a screw compressor (1) by processing a screw rotor base material (120),
A support step for rotatably supporting the screw rotor base material (120) around a predetermined rotation axis (A);
While rotating the screw rotor base material (120) supported in the supporting step around the rotation axis (A), the screw rotor base material (120) is centered on the spiral groove (41) and the rotation axis (A). A first machining step for machining a reference surface (48a, 48b) which is a cylindrical surface;
A re-supporting step for re-supporting the screw rotor base material (120) with reference to the reference surfaces (48a, 48b);
A shaft member insertion hole (47) is inserted into the screw rotor base material (120) supported in the re-supporting step, and the axis of the hole (47) coincides with the axis of the reference plane (48a, 48b). The screw rotor manufacturing method characterized by including the 2nd process process processed like this. In claim 1,
The screw rotor base material (120) is formed with a pilot hole (121) for a shaft member insertion hole (47),
In the supporting step, the screw rotor base material (120) is inserted into the lower hole (121) through a shaft-shaped jig (340) provided to be rotatable around the predetermined rotation axis (A). attachment,
In the re-supporting step, the screw rotor base material (120) is removed from the jig (340), and the screw rotor base material (120) is re-supported with reference to the reference surfaces (48a, 48b),
In the second processing step, the lower hole (121) of the screw rotor base material (120) is processed to finish the shaft member insertion hole (47). Method. A screw rotor manufacturing method for manufacturing a screw rotor (40) attached to a shaft member (21) and rotatably supported in a screw compressor (1) by processing a screw rotor base material (120),
A support step of rotatably supporting a screw rotor base material (120) in which a hole (47) for inserting a shaft member is formed around a predetermined rotation axis (A);
While rotating the screw rotor base material (120) supported in the supporting step around the rotation axis (A), the screw rotor base material (120) is centered on the spiral groove (41) and the rotation axis (A). A first machining step for machining a reference surface (48a, 48b) which is a cylindrical surface;
Re-support by inserting a shaft member (21) through the hole (47) of the screw rotor base material (120) and re-supporting the screw rotor base material (120) with reference to the reference surfaces (48a, 48b) Process,
The supported portion (21a, 21b) supported by the bearing (14, 61) when mounted on the screw compressor (1) in the shaft member (21) with the screw rotor base material (120) re-supported. And a second machining step in which the axis of the supported portion (21a, 21b) is matched with the axis of the reference surface (48a, 48b). . In any one of Claims 1 thru | or 3,
In the second machining step, the outer shape of the screw rotor base material (120) is further finished so that the axis of the outer shape coincides with the axis of the reference surface (48a, 48b). A screw rotor manufacturing method. In any one of Claims 1 thru | or 4,
The screw rotor (40) has a small diameter part (46) whose outer diameter is smaller than the part (40a) in which the spiral groove (41) is formed, and is provided at one end in the axial direction thereof.
The small diameter portion (46) is fitted with a bearing holder (60) when the screw rotor (40) is mounted on the screw compressor (1), and the bearing holder (60), the screw rotor (40), It is configured so that a bent gap is formed between
In the first machining step, the reference surface (48a) is machined into the small diameter portion (46). In any one of Claims 1 thru | or 4,
The screw rotor manufacturing method, further comprising a deletion step of deleting a portion of the screw rotor base material (120) where the reference surface (48b) is processed after the second processing step. In any one of Claims 1 thru | or 6,
In the first processing step, the reference surface (48a, 48b) is processed after the spiral groove (41) is processed in the screw rotor base material (120).

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