Rotor balance adjustment procedure

Abstract

A balance adjustment method for a rotor in which a turbine wheel and a compressor wheel are connected via a rotary shaft, comprising: an imbalance detection step of detecting an imbalance position and amount of the rotor after a first balance correction step of correcting a balance of the rotor by cutting the compressor wheel and / or a nut member connecting the compressor wheel to the rotary shaft; a cutout target portion determination step of determining, based on the imbalance position and amount of the rotor detected in the imbalance detection step, a cutout target area including an imbalance correction position of the turbine wheel and a removal amount in the cutout target area; a second balance correction step of correcting the balance of the rotor by repeatedly irradiating the cutout target area determined in the cutout target portion determination step with laser light using a laser marker device, thereby removing the removal amount from the turbine wheel; and a clipping condition determining step of determining, with reference to at least a piece of unit clipping information, an irradiation frequency of the laser light and a scanning speed of the laser light of the laser marker device are associated with a unit removal amount, which is a removal amount per unit area, the irradiation frequency of the laser light and the scanning speed of the laser light in the second balance correction step from the clipping target range and the removal amount determined in the clipping target portion determining step.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a balance adjustment method for a rotor in which a turbine wheel and a compressor wheel are connected via a rotary shaft. BACKGROUND

[0002] A turbocharger uses energy from an exhaust gas emitted by an internal combustion engine (such as an engine) to supercharge a gas (such as air) sent to the internal combustion engine, thereby improving performance of the internal combustion engine and improving fuel efficiency.

[0003] The turbocharger may include a rotor in which a turbine wheel and a compressor wheel are mechanically connected via a rotating shaft, and a housing for rotatably receiving the above-described rotor. Furthermore, the above-described housing may include a bearing housing for receiving a bearing for rotatably supporting the rotating shaft, a turbine housing for receiving a turbine wheel, and a compressor housing for receiving a compressor wheel.

[0004] If an imbalance (an unbalanced weight with respect to a rotation axis of the rotor) is caused in the rotor described above, the turbocharger may cause vibration due to a centrifugal force generated by an imbalance during rotation of the rotor and may generate noise caused by the vibration described above.

[0005] Conventionally, as a method for adjusting balance during turbocharger rotation, double-plane correction is known. This correction removes imbalance by cutting the compressor wheel and a nut connecting the compressor wheel to the rotating shaft in a cartridge of the turbocharger with an end mill, a grindstone, or the like. The cartridge described above is obtained by mounting the bearing and bearing housing described above on the rotor described above. Performing double-plane correction on the cartridge also removes imbalance caused when individual components constituting the cartridge are assembled. Citation listPatent literature

[0006] Patent Document 1: JP2011-112514A

[0007] Document DE 10 2016 106 676 A1 relates to a rotating body balance correction device and a rotating body balance correction method that correct the balance of a rotating body. The balance of the rotating body is corrected by irradiating a laser with a laser beam device onto a first machining section of the rotating body, which is determined based on the measurement result, and by ablating this machining section. After the first machining section of the rotating body has been ablated, the balance of the rotating body is measured again.If the measurement result is a result where the balance correction is insufficient, the rotating body is rotated at a speed lower than a rotation speed of the rotating body when the first machining portion is ablated, and the laser is irradiated through the laser beam section onto a second machining portion of the rotating body determined based on the re-measurement of the balance, and the second machining portion is ablated.

[0008] Document DE 10 2016 111 785 A1 relates to an unbalance correction device for a rotor, such as a compressor impeller or a turbine wheel of a turbocharger. Specifically, an unbalance correction position of a turbine wheel head is irradiated with a laser beam in such a way that an outer peripheral portion of the turbine wheel head remains intact. A groove formed by the laser irradiation is formed such that the depth of the groove is shallower toward a side closer to the outer periphery of the turbine wheel head. SUMMARYTechnical problem

[0009] With the above-described dual-plane correction, it is possible to significantly reduce cartridge imbalance. However, if an imbalance remains in the cartridge even after the above-described dual-plane correction is performed and the vibration acceleration (G value) increases, further balance adjustment is required. It is conceivable to reduce the vibration acceleration (G value) by performing balance correction on the turbine wheel of the cartridge. However, since the turbine wheel is generally made of a difficult-to-cut material, such as a nickel-based superalloy, there is a problem that removal processing with the accuracy required for fine balance adjustment after the above-described dual-plane correction is difficult in the above-described cutting.

[0010] Patent Document 1 discloses that balance correction for a rotor is performed by irradiating an imbalance correction position of the rotor with laser light in the axial direction of the rotor while the rotor is rotating, and removing the mass of the imbalance correction position described above. However, a laser processing machine for metal processing that cuts or shears a metal material by laser light irradiation is expensive, which may lead to an increase in equipment costs. Furthermore, as a result of intensive research, the present inventors have found that since the laser processing machine for metal processing described above has a large laser light output, removal processing with the accuracy required for fine balance adjustment after the above-described double-plane correction is difficult.

[0011] In view of the above problems, it is an object of at least one embodiment of the present disclosure to provide a balance adjustment method for the rotor capable of suppressing the increase in equipment costs as well as capable of improving accuracy in balance adjustment of the rotor. Solution to the problem

[0012] A balance adjustment method for a rotor according to the present disclosure is a balance adjustment method for a rotor in which a turbine wheel and a compressor wheel are connected via a rotating shaft, comprising an imbalance detection step of detecting an imbalance position and an imbalance amount of the above-described rotor after a first balance correction step of correcting a balance of the above-described rotor by cutting at least one of the above-described compressor wheel and a nut member connecting the above-described compressor wheel to the above-described rotating shaft, a cutout target portion determination step of determining, based on the imbalance position and the imbalance amount of the above-described rotor detected in the above-described imbalance detection step, a cutout target area,which includes an imbalance correction position of the above-described turbine wheel and a removal amount in the above-described cutout target area, and a second balance correction step of correcting the balance of the above-described rotor by repeatedly irradiating the above-described cutout target area, which was determined in the above-described cutout target portion determination step, with laser light from a laser marker device to remove the above-described removal amount from the above-described turbine wheel, and a cutout condition determination step of determining, with reference to at least a piece of unit cutout information, an irradiation frequency of the laser light and a scanning speed of the laser light of the laser marker device are associated with a unit removal amount, which is a removal amount per unit area,the irradiation frequency of the laser light and the scanning speed of the laser light in the second balance correction step from the cut-out target area and the distance amount determined in the cut-out target section determination step.

[0013] A turbocharger according to the present disclosure is a turbocharger including a rotor in which a turbine wheel and a compressor wheel are connected via a rotating shaft. The above-described turbine wheel has a laser marking engraved on a peripheral surface of a hub portion by a laser marking device. Beneficial effects

[0014] According to at least one embodiment of the present disclosure, a balance adjustment method for a rotor is provided which is capable of suppressing an increase in equipment costs and is capable of improving accuracy in balance adjustment of the rotor. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a flowchart of a rotor balance adjustment method according to one embodiment. Fig. 2 is a schematic configuration view schematically showing the configuration of a cartridge of a turbocharger in an embodiment. Fig. 3 is a schematic configuration view schematically showing the configuration of an imbalance detecting device and a laser marker device used for the rotor balance adjusting method according to an embodiment. Fig. 4 is an explanatory view for describing a cutout target area of ​​a turbine wheel in an embodiment. Fig. 5 is an explanatory view for describing the cutout target area of ​​the turbine wheel in an embodiment. Fig. 6 is an explanatory view for describing a trajectory of a laser irradiation target position per scan in the clipping target area. Fig. 7 is a graph showing a relationship between a rotor speed and the vibration acceleration (G-value) before a first compensation correction step. Fig. Figure 8 is a graph showing a relationship between the rotor speed and the vibration acceleration (G value) after the first compensation correction step. Fig. Figure 9 is a graph showing a relationship between the rotor speed and the vibration acceleration (G-value) after a second compensation correction step. Fig. 10 is an explanatory view for describing the cutout target area of ​​the turbine wheel in an embodiment. Fig. 11 is an explanatory view for describing the cutout target area of ​​the turbine wheel in an embodiment. Fig. 12 is a flowchart of the rotor balance adjustment method according to one embodiment. Fig. 13 is an explanatory diagram for describing an example of unit clipping information in an embodiment. Fig. 14 is an explanatory table for describing an example of the unit clipping information and unit clipping period information in an embodiment. DETAILED DESCRIPTION

[0015] Embodiments of the present disclosure will be described below with reference to the accompanying drawings. However, unless specifically identified, dimensions, materials, shapes, relative positions, and the like of components described or shown in the drawings as the embodiments are intended to be interpreted as illustrative only and are not intended to limit the scope of the present disclosure.

[0016] For example, an expression of a relative or absolute arrangement, such as "in a direction", "along a direction", "parallel", "orthogonal", "centered", "concentric" and "coaxial" should not be construed as indicating only the arrangement in a strict literal sense, but also includes a condition in which the arrangement is relatively shifted by a tolerance or by an angle or a distance, whereby it is possible to achieve the same function.

[0017] For example, an expression of a same state, such as "same", "equal", and "uniform", should not be construed to indicate only the state in which the characteristic is strictly the same, but also includes a state in which there is a tolerance or difference that can still achieve the same function.

[0018] Furthermore, for example, an expression of a shape such as a rectangular shape or a tubular shape shall not only be construed as the geometrically strict shape, but also includes a shape with bumps or beveled corners within the range where the same effect can be achieved.

[0019] On the other hand, the expression “comprising”, “containing” or “having” a constitutional element is not an exclusive expression that excludes the presence of other constitutional elements.

[0020] The same configurations are indicated by the same reference numerals and cannot be described again in detail.

[0021] Fig. 1 is a flowchart of a rotor balance adjustment method according to one embodiment. Fig. 2 is a schematic configuration view schematically showing the configuration of a cartridge of a turbocharger in an embodiment. Fig. 3 is a schematic configuration view schematically showing the configuration of an imbalance detecting device and a laser marker device used for the rotor balance adjusting method according to an embodiment.

[0022] A balance adjustment method 1 for the rotor according to some embodiments is a method for adjusting the balance of a rotor 3 in which a turbine wheel 5 and a compressor wheel 6 are mechanically connected via a rotary shaft 4, as shown in Fig. 2. In the balance adjustment method 1 for the rotor described above, a balance adjustment of the rotor 3 is carried out in a state in which the components are assembled in a cartridge 20 of a turbocharger 2, as shown in Fig. 2 shown.

[0023] (Rotor, Turbocharger) As in Fig. 2, the rotor 3 includes the rotating shaft 4 having a longitudinal direction along an axis L of the rotating shaft 4, the turbine wheel 5 mechanically connected to one end portion 41 of the rotating shaft 4 in the longitudinal direction, and the compressor wheel 6 mechanically connected to another end portion 42 of the rotating shaft 4 in the longitudinal direction.

[0024] As in Fig. 2, the turbine wheel 5 includes a hub 51 extending along the axial direction along the axis L of the rotating shaft 4, a plurality of blades 53 arranged on an outer peripheral surface 52 of the hub 51, and a hub portion 55 arranged coaxially with the hub 51 and protruding from an end portion 54 of the hub 51 in the above-described axial direction.

[0025] In the illustrated embodiment, the turbine wheel 5 is fixed to the rotating shaft 4 by causing a central portion of a rear surface 511 of the hub 51 to abut against one end portion 41 of the rotating shaft 4, and a periphery of the abutting portion is joined by welding. The rotating shaft 4 and the turbine wheel 5, which are joined by welding, are collectively referred to as the turbine rotor 50. The method for joining the rotating shaft 4 and the turbine wheel 5 is not limited to joining by welding.

[0026] As in Fig. 2, the compressor wheel 6 includes a hub 61 extending along the axial direction along the axis L of the rotating shaft 4, and a plurality of blades 63 arranged on an outer peripheral surface 62 of the hub 61.

[0027] In the illustrated embodiment, the compressor wheel 6 is fixed to the rotating shaft 4 by screw fastening. A through hole 64 is formed in the compressor wheel 6, penetrating the hub 61 in the axial direction along the above-described axis L. In the compressor wheel 6, the other end portion 42 of the rotating shaft 4 is inserted through the through hole 64, and a protruding portion 44 of the rotating shaft 4 protrudes from a leading edge end 65 of the hub 61. The compressor wheel 6 is fixed to the rotating shaft 4 by screwing an internally threaded portion 211 of a nut member 21 into an externally threaded portion 451 formed on the outer peripheral surface 45 in the protruding portion 44 of the rotating shaft 4. That is, the nut member 21 mechanically connects the compressor wheel 6 to the rotating shaft 4. The method for connecting the rotating shaft 4 and the compressor wheel 6 is not limited to screw fastening.

[0028] As in Fig. 2, the cartridge 20 of the turbocharger 2 includes the rotor 3 described above, a bearing 22 for rotatably supporting the rotary shaft 4 of the rotor 3, and a bearing housing 23 for receiving the bearing 22. As shown in Fig. As shown in Figure 2, the turbocharger 2 includes the cartridge 20, a turbine housing 24 configured to receive the turbine wheel 5, and a compressor housing 25 configured to receive the compressor wheel 6. Both the turbine housing 24 and the compressor housing 25 are assembled to the cartridge 20 after the balance adjustment of the rotor 3 is completed, and are thus indicated by a double-dotted chain line in the drawing. Both the turbine housing 24 and the compressor housing 25 are mechanically connected to the bearing housing 23 by a fastener such as a fastening bolt or a V-clamp. (Rotor balance adjustment procedure)

[0029] As in Fig. 1, the balance adjustment method 1 for the rotor according to some embodiments includes a cartridge mounting step S101, a first imbalance detection step S102, a first cutout target portion determination step S103, a first balance correction step S104, a second imbalance detection step S105 (imbalance detection step), a second cutout target portion determination step S106 (cutout target portion determination step), and a second balance correction step S107.

[0030] The cartridge assembly step S101 involves assembling the cartridge 20 by assembling individual components that form the cartridge 20. Before the cartridge assembly step S101, a balance adjustment may be performed on each of the components (such as the turbine rotor 50 and the compressor wheel 6) that form the cartridge 20 during rotation of the individual component.

[0031] The first imbalance detection step S102 includes detecting an imbalance position and an amount (mass) of the rotor 3 of the cartridge 20 after the cartridge assembly step S101. More specifically, as shown in Fig. 3, in the cartridge 20, the rotor 3 is rotatably supported by an imbalance detection device 7 in the first imbalance detection step S102.

[0032] In the illustrated embodiment, as shown in Fig. As shown in Figure 3, the imbalance detection device 7 includes two housing members 71 (a turbine-side housing member 71A and a compressor-side housing member 71B) and two bearing mechanisms 72 (a turbine-side bearing mechanism 72A and a compressor-side bearing mechanism 72B). The imbalance detection device 7 supports the cartridge 20 by sandwiching the bearing housing 23 of the cartridge 20 with the turbine-side housing member 71A for internally accommodating the turbine wheel 5 and the compressor-side housing member 71B for internally accommodating the compressor wheel 6 from both sides in the axial direction along the above-described axis L, and pressing at least one of the two housing members 71 toward the other through the two bearing mechanisms 72.The turbine-side bearing mechanism 72A is connected to the turbine-side housing member 71A, and the compressor-side bearing mechanism 72B is connected to the compressor-side housing member 71B. Each of the two bearing mechanisms 72 is fixed to a floor of a factory or the like so as not to move when the cartridge 20 is pressed, and is also connected to a corresponding one of the housing members 71 via a vibration isolation member 73 (for example, an elastic member such as rubber).

[0033] In the Fig. In the embodiment shown in Figure 3, a pressing device 74 provided for the compressor-side bearing mechanism 72B is configured to press the compressor-side housing member 71B toward the cartridge 20. As the pressing device 74, for example, a piston device configured to be capable of expanding and contracting a piston rod by receiving air pressure or hydraulic pressure may be specified.

[0034] As in Fig. 3, the imbalance detection device 7 includes a rotating device 75 configured to rotate the rotor 3 by supplying a gas (such as air) to either the turbine wheel 5 or the compressor wheel 6, and a detecting device 76 for detecting an imbalance from the rotating rotor 3.

[0035] In the illustrated embodiment, the rotating device 75 includes a fan 751 configured to send the gas, and an air supply pipe 752 connected at one end portion to the fan 751 and at another end portion to the compressor-side housing member 71B, and configured to supply air from the fan 751 to the compressor wheel 6 housed in the compressor-side housing member 71B via the air supply pipe 752. When the compressor wheel 6 rotates, the rotating shaft 4 and the turbine wheel 5 rotate. In some other embodiments, the rotor 3 may be configured to rotate by connecting the other end portion of the air supply pipe 752 to the turbine-side housing member 71A to supply the air from the fan 751 to the turbine wheel 5.

[0036] In the illustrated embodiment, the detection device 76 includes an acceleration sensor (vibration sensor) 761 for detecting vibration of the rotor 3, a rotation angle sensor 762 for detecting a phase of the rotor 3, and a computing device (such as a computer) 763 configured to calculate the imbalance position and amount (mass) of the rotor 3 from a vibration signal detected by the acceleration sensor 761 and the phase of the rotor 3 detected by the rotation angle sensor 762. The first imbalance detection step S102 involves detecting, by the acceleration sensor 761, the vibration during rotation of the rotor 3 caused by the imbalance of the rotating rotor 3. At the same time as the detection of the vibration by the acceleration sensor 761, the phase of the rotor 3 is detected by the rotation angle sensor 762.Based on a relationship between the vibration signal detected by the acceleration sensor 761 and the phase of the rotor 3 detected by the rotation angle sensor 762, the computing device 763 calculates the imbalance position and amount (mass) of the rotor 3 that cause the vibration. It is only necessary that the detecting device 76 be configured to be able to detect the imbalance position and amount (mass) from the rotor 3, and the present disclosure is not limited to the illustrated configuration.

[0037] The first cutout target portion determining step S103 includes determining, based on the imbalance position and amount of the rotor 3 detected in the first imbalance detecting step S102, a position (imbalance correction position) and a cutout amount that are optimal for balancing the rotor 3 in at least one of the compressor wheel 6 and the nut member 21.

[0038] In a specific embodiment, at least a piece of first relationship information (such as an effect vector) indicating a relationship between a mass (unit weight) cut from either the compressor wheel 6 or the nut member 21 of the rotor 3 and a change in the magnitude of vibration due to the above-described cutting of the mass is acquired in advance through an experiment using the cartridge 20 of the same model number (same product). If a target to be cut from the rotor 3 is different, the above-described first relationship information will also be different, making it necessary to acquire the above-described first relationship information for each of the compressor wheel 6 and the nut member 21.Then, based on the imbalance position and amount (initial imbalance) of the rotor 3 detected in the first imbalance detection step S102 and the first relationship information, first cancellation information is calculated including the position (imbalance correction position) and the cut-out amount optimal for balancing the rotor 3.

[0039] The first balance correction step S104 includes correcting the balance of the rotor 3 by cutting the compressor wheel 6 and / or the nut member 21 connecting the compressor wheel 6 to the rotating shaft 4 in the cartridge 20 described above.

[0040] In a specific embodiment, the compressor wheel 6 or the nut member 21 is cut based on the imbalance correction position and the cutout amount (cutout information) determined in the first cutout target portion determination step S103. The first balance correction step S104 includes cutting, for example, an outer surface 212 of the nut member 21 or an outer peripheral surface 62 of the hub 61 of the compressor wheel 6 to remove the imbalance of the rotor 3.

[0041] Since the nut member 21 can be easily attached to / detached from the cartridge 20 and is cheaper than the compressor wheel 6, cutting of the nut member 21 can be prioritized. The first balance correction step S104 does not need to include performing cutting in a state where the rotor 3 is rotated.

[0042] The second imbalance detection step S105 (imbalance detection step) involves detecting the imbalance position and amount (mass) of the rotor 3 by the same method as the first imbalance detection step S102 described above, after the first balance correction step S104. That is, based on the relationship between the vibration signal detected in the state where the rotor 3 is rotated and the phase of the rotor 3 corresponding to the vibration signal, the imbalance position and amount (mass) of the rotor 3 causing the vibration are specified.

[0043] Fig. 4 and Fig. 5 are each an explanatory view for describing the cutout target area of ​​the turbine wheel in an embodiment. The second cutout target portion determination step S106 (cutout target portion determination step) includes determining, based on the imbalance position and amount of the rotor 3 detected in the second imbalance detection step S105, a cutout target area 57 (see Fig. 4, Fig. 5), which includes an imbalance correction position P1 (the optimal position for balancing the rotor 3) of the turbine wheel 5 and a removal amount in the cutout target area 57. Herein, the cutout target area 57 is an area to be cut out by a laser marker device 8, which will be described later in the second balance correction step S107, and the removal amount in the cutout target area 57 is an amount (mass) removed from the turbine wheel 5 by the laser marker device 8 in the second balance correction step S107.

[0044] In the illustrated embodiment, as shown in Fig. 4, Fig. 5, the cutout target area 57 is located on a circumferential surface 551 of the hub portion 55 of the above-described turbine wheel 5. The circumferential surface 551 of the hub portion 55 is uniformly spaced from a rotational center axis RC, and thus, it is unnecessary to change the shape of the cutout target area 57 for each circumferential position, making it easy to determine the cutout target area 57. In some other embodiments, the cutout target area 57 may be located anywhere other than the circumferential surface 551 of the hub portion 55. Further, in the illustrated embodiment, the cutout target area 57 is set so that the imbalance correction position P1 is located at the center.

[0045] In the illustrated embodiment, second relationship information (such as an effect vector) indicating a relationship between a mass (such as a unit weight) cut from the turbine wheel 5 of the rotor 3 and a change in the magnitude of vibration due to the above-described cutting of the mass is acquired in advance through an experiment using the cartridge 20 of the same model number (same product). Then, based on the imbalance position and amount (initial imbalance) of the rotor 3 acquired in the second imbalance detection step S105 and the second relationship information, second cancellation information is calculated, including the position (imbalance correction position) and the cutout amount that are optimal for balancing the rotor 3.Then, based on the second deletion information described above, the clipping target area and the removal amount in the clipping target area are determined. For example, by referring to setting information corresponding to the second deletion information, in which the clipping target area 57 and the removal amount in the clipping target area 57 are set, the clipping target area 57 and the removal amount in the clipping target area 57 can be determined from the second deletion information.

[0046] The second balance correction step S107 includes correcting the balance of the rotor 3 by repeatedly irradiating the cutout target area 57 determined in the second cutout target portion determining step S106 (cutout target portion determining step) with laser light 20 from the laser marker device 8 to remove the cutout target area 57 from the turbine wheel 5 by the removal amount described above.

[0047] The laser light of the laser marker device 8 has a maximum output power of not more than 100 W. For example, the laser marker device 8 can be a device used to engrave an object by laser light irradiation. In the illustrated embodiment, as shown in Fig. 3, Fig. As shown in Figure 6, the laser marker device 8 includes a laser light irradiation part 81 configured to irradiate a laser irradiation target position with laser light (such as a pulsed laser), and an irradiation position adjustment part 82 configured to adjust the laser irradiation target position. In the illustrated embodiment, an output power of the laser light emitted from the laser light irradiation part 81 is set to a predetermined value.

[0048] Fig. 6 is an explanatory view for describing a trajectory of the laser irradiation target position per scan in the clipping target area. As in Fig. As shown in Figure 6, the irradiation position adjustment part 82 changes a laser irradiation target position TP so that the entire cut-out target area 57 can be engraved by the laser light for each scan. A trajectory T in Fig. 6 shows an example of the trajectory of the laser irradiation target position TP. The laser marker device 8 repeats scanning several times (preferably not less than 10 times), and the laser irradiation target position follows the trajectory T several times, thereby gradually removing imbalance from the cutout target area 57.

[0049] Fig. Figure 7 is a graph showing a relationship between a rotor speed and the vibration acceleration (G value) before the first compensation correction step. Fig. Figure 8 is a graph showing a relationship between the rotor speed and the vibration acceleration (G value) after the first compensation correction step. Fig. Figure 9 is a graph showing a relationship between the rotor speed and the vibration acceleration (G value) after the second compensation correction step.

[0050] As in Fig. As shown in Figure 7, before the first compensation correction step S104, the rotor 3 has the vibration acceleration (G-value) that often exceeds a reference vibration acceleration RG at both low rotation (such as less than 100,000 rotations) and high rotation (such as not less than 100,000 rotations). In contrast, as shown in Fig. As shown in Figure 8, the imbalance of the rotor 3 after the first balance correction step S104 is significantly reduced by the balance correction in the first balance correction step S104, and particularly at low rotation (such as less than 100,000 rotations), the vibration acceleration (G value) is reduced relative to the reference vibration acceleration RG. However, the rotor 3 after the first balance correction step S104 may have the vibration acceleration (G value) exceeding the reference vibration acceleration RG at high rotation (such as not less than 100,000 rotations).

[0051] Fig. 9 shows a result of performing the second compensation correction step S107 on the rotor 3 whose vibration acceleration (G-value) exceeds the reference vibration acceleration RG in a measurement after the first compensation correction step S104. As shown in Fig. As shown in Figure 9, the imbalance of the rotor 3 after the second balance correction step S107 is significantly improved by the balance correction in the second balance correction step, and at high rotation (such as not less than 100,000 rotations), the vibration acceleration (G value) is reduced relative to the reference vibration acceleration RG. This result indicates that the balance adjustment in the second balance correction step S107 is very effective in fine-tuning the balance of the rotor 3.

[0052] As in Fig. 1, the balance adjustment method 1 for the rotor according to some embodiments includes, after the above-described first balance correction step S104, the second imbalance detection step S105 (imbalance detection step) of detecting the imbalance position and the amount (mass) of the rotor 3, the second cutout target portion determination step S106 (cutout target portion determination step) of determining, based on the imbalance position and the amount (mass) of the rotor 3 detected in the second imbalance detection step S105, the cutout target area 57 (see, for example, Fig. 4) which includes the imbalance correction position P1 of the turbine wheel 5 and the distance amount in the cut-out target area 57, and the second balance correction step S107 of correcting the balance of the rotor 3 by repeatedly irradiating the cut-out target area 57 determined in the second cut-out target portion determination step S106 with the laser light from the laser marker device 8 to remove from the turbine wheel 5 by the above-described distance amount.

[0053] With the above method, the second balance correction step S107 includes correcting the balance of the rotor 3 by repeatedly irradiating the cutout target area 57 with the laser light from the laser marker device 8 to remove the imbalance from the turbine wheel 5 by the above-described removal amount (the removal amount in the cutout target area 57). Here, the laser marker device 8 has a smaller laser light output than a laser processing machine for metal processing and can reduce the removal amount from the turbine wheel 5 per scan in the cutout target area 57. Thus, accurate removal by a desired removal amount is possible by repeatedly scanning the cutout target area 57. That is, the laser marker device 8 is suitable for finely adjusting the balance of the rotor 3 in the second balance correction step S107. Furthermore, the laser marker device 8 can accurately process the turbine wheel 5 even when the turbine wheel 5 is made of a material that is difficult to cut. Thus, with the above method, it is possible to improve the accuracy of the balance adjustment of the rotor 3.Furthermore, since the laser marker device 8 is cheaper than the laser processing machine for metal processing, it is possible to suppress the increase in equipment costs.

[0054] In some embodiments, for example, as in Fig. 4, the above-described cutout target area 57 is located on the peripheral surface 551 of the hub portion 55 of the turbine wheel 5. In the illustrated embodiment, the cutout target area 57 is located on a peripheral surface 551A away from an end surface 552 (tip) of the hub portion 55 by not less than a predetermined distance (such as 1 mm) in the axial direction of the turbine wheel 5 (an extending direction of the rotational center axis RC). The end surface 552 of the hub portion 55 is cut off alone at the time of balance adjustment in the turbine rotor 50, and it may be impossible to secure a sufficient cutting allowance. Thus, the cutout target area 57 is preferably located on the above-described peripheral surface 551A.

[0055] With the above method, the cutout target area 57 is located on the peripheral surface 551 of the hub portion 55 of the turbine wheel 5. In order to remove a part of the turbine wheel 5 as an imbalance from the cutout target area 57 located on the peripheral surface 551 of the hub portion 55, the laser light of the laser marker device 8 is emitted along a direction that intersects with (for example, is orthogonal to) the axial direction of the turbine wheel 5. Herein, due to the removal processing in the cutout target area 57, the hub portion 55 of the turbine wheel 5 has a smaller centrifugal force generated during the rotation of the turbine wheel 5 than the hub 51 and the blades 53, which makes it possible to reduce an adverse effect (such as a decrease in high-cycle fatigue strength).

[0056] Then, since the peripheral surface 551 of the hub portion 55 has a longer distance from the rotational center axis RC of the hub portion 55 (turbine wheel 5) than the end surface 552 of the hub portion 55, it is possible to reduce the amount of removal required to eliminate the imbalance. Furthermore, at the time of balancing in the turbine rotor 50, the end surface 552 of the hub portion 55 is cut off alone, and it may be impossible to secure a sufficient cutting allowance. However, the peripheral surface 551 of the hub portion 55 can secure a sufficient cutting allowance even if the amount of removal is large.

[0057] In some embodiments, for example, as in Fig. As shown in Figure 4, the above-described cutout target area 57 has a long axis LA along the circumferential direction of the turbine wheel 5 and a short axis SA along the axial direction of the above-described turbine wheel. By repeatedly irradiating the cutout target area 57 with the laser light from the laser marker device 8 (see Fig. 3, Fig. 6) a laser mark 58 engraved by the laser marker device 8 is formed on the peripheral surface 551 of the hub portion 55.

[0058] In the illustrated embodiment, the cutout target area 57 is set in a rectangular shape, and the laser mark 58 has a rectangular concave shape. The long axis LA may extend in the same direction as the circumferential direction of the turbine wheel 5, or may be inclined within a range of ±45° with respect to the circumferential direction of the turbine wheel 5. Furthermore, the short axis SA may extend in the same direction as the axial direction of the turbine wheel 5, or may be inclined within a range of ±45° with respect to the axial direction of the turbine wheel 5.

[0059] With the above method, the cutout target area 57 has the long axis LA along the circumferential direction of the turbine wheel 5, and has the short axis SA along the axial direction of the turbine wheel 5. Since the peripheral surface 551 of the hub portion 55 of the turbine wheel 5 has the circumferential length longer than the axial length, the cutout target area 57 having the long axis LA along the circumferential direction easily secures its area.

[0060] In some embodiments, the condition 1.5 ≤ L2 / L1 ≤ 100 is satisfied, where L1 is a length of the short axis SA extending along the axial direction of the turbine wheel 5, and L2 is a length of the long axis LA extending along the circumferential direction of the turbine wheel 5.

[0061] If the length L2 of the long axis LA of the cutout target area 57 is too long, the distances from the imbalance correction position to both end portions 571, 572 of the long axis LA extending along the circumferential direction of the turbine wheel 5 increase, which may make the two end portions less effective in correcting imbalance. Furthermore, if the length L2 of the long axis LA of the cutout target area 57 is too short, it may be impossible to remove the amount of imbalance required to eliminate the imbalance. With the above method, since the condition 1.5 ≤ L2 / L1 ≤ 100 is satisfied, it is possible to suppress the increase in the distances from the imbalance correction position P1 to the two end portions 571, 572 of the long axis LA, and to make the two end portions 571, 572 effective in correcting the imbalance over the entire cutout target area 57.Furthermore, it is possible to secure the amount of removal needed to eliminate the imbalance.

[0062] Fig. 10 is an explanatory view for describing the cutout target area of ​​the turbine wheel in one embodiment. In some embodiments, as shown in Fig. As shown in Figure 10, the above-described cutout target area 57 has the long axis LA along the circumferential direction of the turbine wheel 5 and the short axis SA along the axial direction of the above-described turbine wheel. The above-described cutout target area 57 includes a first cutout target area 57A and a second cutout target area 57B arranged along the first cutout target area 57A in the axial direction of the turbine wheel 5. The area of ​​the second cutout target area 57B can be adjusted based on the imbalance position and amount (mass) detected after the balance adjustment in the first cutout target area 57A.

[0063] With the above method, since each of the plurality of cutout target areas 57 (the first cutout target area 57A, the second cutout target area 57B) has the short axis SA along the axial direction of the turbine wheel 5, the plurality of cutout target areas 57 can be located on the peripheral surface 551 of the hub portion 55 of the turbine wheel 5. Furthermore, since the plurality of cutout target areas 57 are located on the peripheral surface 551 of the hub portion 55 of the turbine wheel 5 adjacent to each other in the axial direction of the turbine wheel 5, compared to a case where the single cutout target area 57 is located, it is possible to increase the amount removable from the hub portion 55 of the turbine wheel 5 while suppressing an excessive increase in the long axis LA of each cutout target area 57.

[0064] In the rotor balance adjustment method 1 described above, the second imbalance detection step S105 (imbalance detection step), the second cutout target portion determination step S106 (cutout target portion determination step), and the second balance correction step S107 may be performed multiple times in this order.

[0065] In some embodiments, the range of the above-described second clipping target area 57B may be adjusted based on the imbalance position and amount (mass) detected after the balance adjustment in the first clipping target area 57A. In this case, it is possible to improve the accuracy of the balance adjustment in the second clipping target area 57B.

[0066] Fig. 11 is an explanatory view for describing the cutout target area of ​​the turbine wheel in one embodiment. In some embodiments, as shown in Fig. As shown in Fig. 11, the above-described cutout target area 57 has the short axis SA along the circumferential direction of the turbine wheel 5, and the long axis LA along the axial direction of the turbine wheel 5. In this case, it is possible to suppress an increase in the distances from the imbalance correction position P1 to both end portions 571A, 572A of the short axis SA extending along the circumferential direction of the turbine wheel 5, allowing the two end portions 571A, 572A to be effective in correcting the imbalance over the entire cutout target area 57.

[0067] Fig. 12 is a flowchart of the rotor balance adjustment method according to one embodiment. In some embodiments, as in Fig. As shown in Fig. 12, the above-described rotor balance adjustment method 1 further includes a clipping condition determination step S201. The clipping condition determination step S201 is performed after the second clipping target portion determination step S106 (clipping target portion determination step) and before the second balance correction step S107.

[0068] Fig. 13 is an explanatory diagram for describing an example of unit cutout information in an embodiment. Before the cutout condition determination step S201, at least a piece of unit cutout information UE is prepared in advance, wherein a combination of a laser light irradiation frequency TI and a laser light scanning speed SS of the laser marker device 8 is associated with a unit removal amount UR, which is a removal amount per unit area. The unit cutout information UE can be prepared before starting the balance adjustment process 1. The unit cutout information UE can be acquired in advance through an experiment using the same type of material as the turbine wheel 5.However, in order to improve the accuracy, the unit cutout information UE is preferably acquired in advance by an experiment using the cartridge 20 of the same model number (the same product).

[0069] The above-described at least one piece of unit clipping information UE may include not only the information (information indicating the relationship) about the combination of the irradiation frequency TI and the scanning speed SS and the unit removal amount UR in the above-described combination, but also information (individual information such as numerical values) about the irradiation frequency TI, the scanning speed and the unit removal amount whose relationship is indicated by the information (information indicating the relationship). Furthermore, in a specific embodiment, the above-described at least one piece of unit clipping information UE is electronic data, such as a map, a table, or a machine learning model, and is stored in a database. The above-described computing device 763 has a general configuration as a computer (e.g., a CPU, a memory, an internal storage, and the like) and is configured to be able to refer to the above-described database. The above-described database may be installed in the computing device 763.

[0070] Fig. Fig. 13 is a diagram showing the laser light irradiation frequency TI of the laser marker device 8 on the abscissa and the unit distance UR (the distance per unit area) on the ordinate, and graphically representing a different marker for each of the laser light scanning speeds SS (25 mm / s, 50 mm / s, 100 mm / s). That is, the graphical representation in Fig. 13 indicates the unit cutout information UE (including the information indicating the relationship described above and the individual information), and Fig. Figure 13 shows, by approximate lines AL1, AL2, AL3 for the scanning speeds SS and a plurality of graphic representations, a plurality of pieces of unit cutout information UE, which differ in the irradiation frequency TI and the scanning speed SS. Furthermore, the approximate lines AL1, AL2, AL3 for the scanning speeds SS in Fig. 13 respectively indicate the plurality of pieces of unit clipping information UE which differ in the irradiation frequency TI. The laser light irradiation frequency TI of the laser marker device 8 indicates the number of repetitions of the above-described scan (the number of times following the trajectory T), and the laser light scanning speed SS indicates a moving speed at which the irradiation position adjusting part 82 moves through the laser irradiation target position TP.

[0071] The clipping condition determining step S201 includes referring to the above-described at least one piece of unit clipping information UE (S201A) and determining the laser light irradiation frequency TI and the laser light scanning speed SS in the second balance correcting step S107 from the clipping target area 57 and the distance amount in the clipping target area 57 determined in the second clipping target portion determining step S106 (clipping target portion determining step) (S201B).

[0072] The clipping condition determination step S201 includes obtaining the distance amount per unit area in the clipping target region 57 by dividing the distance amount in the clipping target region 57 by the area of ​​the clipping target region 57. By referring to at least a piece of unit clipping information UE, it is possible to determine the irradiation frequency TI and the scanning speed SS corresponding to the distance amount per unit area in the clipping target region 57. In a specific embodiment, the above-described computing device 763 refers to the database storing the unit clipping information UE (S201A) and performs the above-described step S201B.

[0073] With the above method, based on the relationship (unit cutout information UE) between the laser light irradiation frequency TI and the laser light scanning speed SS of the laser marker device 8 and the unit removal amount UR, which is the removal amount per unit area, the laser light irradiation frequency TI and the laser light scanning speed SS are determined in the second balance correction step S107 from the cutout target area 57 and the removal amount determined in the second cutout target portion determination step S106 (cutout target portion determination step). In this case, a difference between the removal amount determined in the second cutout target portion determination step S106 and an actual amount removed in the second balance correction step S107 can be reduced, making it possible to remove the imbalance of an appropriate amount from the turbine wheel 5.Thus, with the above method, it is possible to improve an accuracy in the balance adjustment of the rotor 3.

[0074] Fig. 14 is an explanatory table for describing an example of the unit clipping information and unit clipping period information in an embodiment. Fig. Fig. 14 shows a plurality of pieces of unit clipping information UE (UE1 to UE5) with different scanning speeds SS (SS1 to SS5) and irradiation frequencies TI (TI1 to TI5) with respect to the same unit distance UR (UR1). Here, each of the scanning speeds SS (SS1 to SS5) is Fig. 14 higher because an accompanying numerical value is larger. That is, SS1 is the lowest, and SS5 is the highest. As the scanning speed SS increases, the distance per scan decreases, and thus each of the irradiation frequencies TI (TI1 to TI5) decreases in Fig. 14 because an accompanying numerical value is larger.

[0075] Fig. 14 also shows periods (unit cutout periods UT, UT1 to UT5) required for the laser marker device 8 to cut out the unit distance amount UR according to the cutout conditions (the respective combinations of the scanning speeds SS and the irradiation frequencies TI) under the above-described cutout conditions. Fig. 14 further shows the plurality of pieces of information (unit cutout period information) in which the cutout conditions and the unit cutout periods UT are associated with each other. Each of the unit cutout periods UT (UT1 to UT5) in Fig. 14 corresponds to a corresponding combination of the scanning speeds SS and the irradiation frequencies TI, and is longer because an accompanying numerical value is larger. That is, UT1 is the shortest period, and UT5 is the longest period. Furthermore, Fig. 14 cycle times CT (CT1 to CT5) under the respective cutting conditions. The "cycle time" means a time required for the laser marker device 8 to remove the imbalance from the turbine wheel 5 by the amount required for balance adjustment in the second balance correction step S107.

[0076] In some embodiments, for example, as in Fig. As shown in Figure 14, the above-described at least one piece of unit clipping information UE includes a plurality of pieces of unit clipping information UE each having a different scanning speed SS with respect to the same unit distance UR described above. The above-described clipping condition determining step S201 includes determining, as the irradiation frequency TI and the scanning speed SS in the second balance correction step S107, the irradiation frequency TI and the scanning speed SS of the unit clipping information UE having the highest scanning speed SS among the plurality of pieces of unit clipping information UE.

[0077] In Fig. 14, since the unit clipping information UE5 has the highest scanning speed SS among the plurality of pieces of unit clipping information UE (UE1 to UE5), the clipping condition determining step S201 includes determining the irradiation frequency TI5 and the scanning speed SS5 of the unit clipping information UE5 as the irradiation frequency TI and the scanning speed SS in the second balance correction step.

[0078] Although the imbalance removal amount per irradiation frequency NI (scan) decreases when the laser light scanning speed SS is increased, it is possible to reduce the difference between the expected imbalance removal amount and the actual imbalance removal amount. That is, it is possible to improve the imbalance removal accuracy. In contrast, when the laser light scanning speed SS is decreased, although the difference between the expected imbalance removal amount and the actual imbalance removal amount increases compared to the case where the scanning speed SS is high, it is possible to increase the imbalance removal amount per irradiation frequency NI (scan).With the above method, since the clipping condition determining step S201 includes determining, as the irradiation frequency NI and the scanning speed SS in the second balance correcting step S107, the irradiation frequency NI and the scanning speed SS of the unit clipping information UE having the highest scanning speed SS among the plurality of pieces of unit clipping information UE, it is possible to improve the imbalance removal accuracy.

[0079] In some embodiments, for example, as in Fig. 14, each scanning speed SS of the plurality of pieces of unit clipping information UE described above is smaller than an upper threshold value USS of the scanning speed SS. The clipping condition determining step S201 includes determining, as the irradiation frequency NI and the scanning speed SS in the second balance correcting step S107, the irradiation frequency NI and the scanning speed SS of the unit clipping information UE having the highest scanning speed SS among the plurality of pieces of unit clipping information UE including the scanning speed SS smaller than the upper threshold value USS.

[0080] In the example shown in Fig. As shown in Figure 14, the scanning speed SS5 of the unit clipping information UE5 is greater than the upper threshold value USS of the scanning speed SS and is thus excluded from the one piece of unit clipping information UE adopted in the second balance correction step S107. The unit clipping information UE4 has the highest scanning speed SS among the plurality of pieces of unit clipping information UE (UE1 to UE4) excluding the unit clipping information UE5, and thus the irradiation frequency TI and the scanning speed SS of the unit clipping information UE4 are determined as the irradiation frequency TI and the scanning speed SS in the second balance correction step.

[0081] When the laser light scanning speed SS is increased, it is possible to improve the imbalance removal accuracy compared to the case where the scanning speed SS is low. However, when the scanning speed SS is increased, the imbalance removal amount per irradiation frequency NI (scan) decreases, which increases the irradiation frequency NI and increases the cycle time CT in the second balance correction step S107. For example, in a manufacturing process of the turbocharger 2 including the rotor 3, if the cycle time CT in the second balance correction step S107 is longer than that in other processes, the productivity of the turbocharger 2 decreases.With the above method, since the irradiation frequency NI and the scanning speed SS of the unit clipping information UE with the highest scanning speed SS among the plurality of pieces of unit clipping information UE including the scanning speed SS smaller than the upper threshold USS are determined as the irradiation frequency NI and the scanning speed SS in the second balance correction step S107, it is possible to make the scanning speed SS smaller than the upper threshold USS in the second balance correction step S107. Thus, it is possible to prevent the cycle time CT from becoming too long in the second balance correction step S107 while improving the imbalance removal accuracy.

[0082] In some embodiments, for example, as in Fig. As shown in FIG. 14, the above-described plurality of pieces of unit clipping information UE includes the plurality of pieces of unit clipping information UE each having a different scanning speed SS with respect to the same unit distance UR described above. The above-described clipping condition determining step S201 includes determining, as the irradiation frequency TI and the scanning speed SS in the second balance correction step S107, the irradiation frequency TI and the scanning speed SS of the unit clipping information UE with the minimum cycle time CT in the above-described second balance correction step among the plurality of pieces of unit clipping information UE.

[0083] In a specific embodiment, a plurality of pieces of unit clipping period information RT are prepared in advance before the clipping condition determination step S201. The unit clipping period information RT includes at least one piece of information indicating the relationship between the combination of the scanning speed SS and the irradiation frequency TI in the unit clipping information UE and the unit clipping period UT. The above-described plurality of pieces of unit clipping period information RT can be prepared before the start of the balance adjustment process 1.The unit clipping period information RT can be acquired by an experiment in advance using the laser marker device 8 or can be acquired by calculating the unit clipping period UT from various conditions such as the scanning speed SS, the irradiation frequency T1, the unit removal amount UR and the trajectory T.

[0084] The clipping condition determination step S201 may include specifying the one piece of unit clipping information UE assumed in the second balance correction step S107 by referring to the plurality of pieces of unit clipping period information RT. The above-described cycle time CT corresponds to the unit clipping period UT when the area of ​​the clipping target region 57 is equal. That is, as shown in Fig. As shown in Figure 14, the cycle time CT increases as the unit cut-out period UT is longer, and the cycle time CT decreases as the unit cut-out period UT is shorter. Each of the cycle times CT (CT1 to CT5) in Fig. 14 is longer because an accompanying numerical value is larger. That is, CT1 is the shortest time, and CT5 is the longest time. Thus, when one piece of unit cutout information UE is specified, a comparison can be made with the unit cutout period UT instead of the cycle time CT. Further, in another specific embodiment, a period obtained by multiplying the unit cutout period UT by the area of ​​the cutout target region 57 is regarded as the cycle time CT, and when one piece of unit cutout information UE is specified, a comparison with the cycle time CT can be made when determining the cutout condition.

[0085] In Fig. 14, since the unit cutout information UE1 has the minimum unit cutout period UT and the cycle time CT among the plurality of pieces of unit cutout information UE (UE1 to UE5), the cutout condition determining step S201 includes determining the irradiation frequency TI1 and the scanning speed SS1 of the unit cutout information UE1 as the irradiation frequency TI and the scanning speed SS described above in the second balance correction step.

[0086] The above-described plurality of pieces of unit clipping period information RT may include not only the information (information indicating the relationship) about the combination of the irradiation frequency TI and the scanning speed SS and the unit clipping period UT in the above-described combination, but also information (individual information such as numerical values) about the irradiation frequency TI, the scanning speed SS, and the unit clipping period UT whose relationship is indicated by the information (information indicating the relationship). Further, in a specific embodiment, the above-described plurality of pieces of unit clipping period information RT are each electronic data, such as a map, a table, or a machine learning model, and are stored in the above-described database.In a specific embodiment, the above-described computing device 763 refers to the database that stores the unit clipping period information RT (S201A) and performs the above-described step S201B.

[0087] With the above method, since the above-described clipping condition determining step S201 includes determining, as the above-described irradiation frequency TI and the above-described scanning speed SS in the second balance correction step S107, the irradiation frequency TI and the scanning speed SS of the unit clipping information UE having the minimum cycle time in the above-described second balance correction step among the plurality of pieces of unit clipping information UE, it is possible to shorten the cycle time in the second balance correction step S107.

[0088] In some embodiments, for example, as in Fig. 14, each scanning speed SS of the plurality of pieces of unit clipping information UE described above is greater than a lower threshold LSS of the scanning speed SS. The clipping condition determining step S201 includes determining, as the irradiation frequency NI and the scanning speed SS in the second balance correcting step S107, the irradiation frequency NI and the scanning speed SS of the unit clipping information UE having the minimum cycle time CT among the plurality of pieces of unit clipping information UE including the scanning speed SS greater than the lower threshold LSS.

[0089] In the example shown in Fig. As shown in Fig. 14, the scanning speed SS1 of the unit clipping information UE1 is smaller than the lower threshold value LSS of the scanning speed SS and is thus excluded from the one piece of unit clipping information UE adopted in the second balance correction step S107. The unit clipping information UE2 has the minimum unit clipping period UT and cycle time CT among the plurality of pieces of unit clipping information UE (UE2 to UE5) excluding the unit clipping information UE1, and thus the irradiation frequency TI and the scanning speed SS of the unit clipping information UE2 are determined as the irradiation frequency TI and the scanning speed (SS) described above in the second balance correction step. When the laser light scanning speed SS is reduced, the imbalance removal amount per irradiation frequency NI (scan) increases compared to the case where the scanning speed SS is high, making it possible to reduce the irradiation frequency NI and shorten the cycle time CT in the second balance correction step S107. However, when the scanning speed SS is reduced, the difference between the expected removal amount and the actual removal amount of the imbalance increases, which reduces the imbalance removal accuracy.

[0090] For example, if, as in Fig. As shown in Figure 13, when the scanning speed SS is high (for example, 50 mm / s, 100 mm / s) in a case where the scanning speed SS is fixed, the laser light irradiation frequency TI of the laser marker device 8 and the unit removal amount UR are in a linear relationship. In contrast, when the scanning speed SS is low (for example, 25 mm / s), the removal amount of the imbalance removed per irradiation frequency NI (scan) is large, and a depth in the cut-out target area 57 increases. As the depth in the cut-out target area 57 increases, the distance between the laser light irradiation part 81 and the laser irradiation target position TP increases compared to the start of the laser light irradiation, making it impossible to narrow the focus of the laser light and remove the unit removal amount UR corresponding to the irradiation frequency TI.Thus, the difference between the expected removal amount and the actual removal amount of the imbalance is increased, which decreases the imbalance removal accuracy.

[0091] With the above method, since the irradiation frequency NI and the scanning speed SS of the unit clipping information UE with the minimum cycle time CT among the plurality of pieces of unit clipping information UE including the scanning speed SS greater than the lower threshold LSS are determined as the irradiation frequency NI and the scanning speed SS in the second balance correction step S107, it is possible to make the scanning speed SS in the second balance correction step S107 greater than the lower threshold LSS. Thus, it is possible to ensure the imbalance removal accuracy while shortening the cycle time CT in the second balance correction step S107.

[0092] In some embodiments described above, although the unit clipping information UE whose scanning speed SS is greater than the upper threshold USS or the unit clipping information UE whose scanning speed SS is less than the lower threshold LSS is excluded from the one piece of unit clipping information UE adopted in the second balance correction step S107, the unit clipping information UE whose unit clipping period UT or cycle time CT is greater than the upper threshold or less than the lower threshold may be excluded from the part of the one piece of unit clipping information UE adopted in the second balance correction step S107.

[0093] For example, in a specific embodiment, the unit clipping period UT corresponding to the irradiation frequency NI and the scanning speed SS of each of the plurality of pieces of unit clipping information UE described above is smaller than an upper threshold UUT of the unit clipping period UT and larger than a lower threshold LUT of the unit clipping period UT. The clipping condition determining step S201 includes determining, among the plurality of pieces of unit clipping information UE including the irradiation frequency NI and the scanning speed SS, the one piece of unit clipping information UE assumed in the second balance correction step S107, which corresponds to the unit clipping period UT that is smaller than the upper threshold UUT and larger than the lower threshold LUT.Furthermore, in a specific embodiment, the cycle time CT corresponding to the unit removal amount UR, the irradiation frequency NI, and the scanning speed SS of each of the plurality of pieces of unit clipping information UE described above is smaller than an upper threshold UCT of the cycle time CT and larger than a lower threshold LCT of the unit clipping period UT. The unit clipping information UE that does not satisfy the condition (for example, smaller than the upper threshold) may be excluded in step S201A or S201B described above, or may not be prepared before step S201A described above.

[0094] In some embodiments, for example, as in Fig. 13, the above-described at least one piece of unit clipping information UE includes the plurality of pieces of unit clipping information UE each having the different scanning speed SS. The above-described clipping condition determining step S201 includes determining, as the irradiation frequency TI and the scanning speed SS in the second balance correction step S107, the irradiation frequency TI and the scanning speed SS of each of first unit clipping information UE6 including a first scanning speed SS6 as the scanning speed SS, and second unit clipping information UE7 including a second scanning speed SS7 higher than the first scanning speed SS6 as the scanning speed SS, among the plurality of pieces of unit clipping information UE.

[0095] The second balance correction step S107 includes a low-speed correction step S107A in which the laser light scanning speed SS is the first scanning speed SS6, and a high-speed correction step S107B in which the laser light scanning speed SS is the second scanning speed SS7.

[0096] In a specific embodiment, the clipping condition determining step S201 includes a step of dividing, based on the first unit clipping information UE6 and the second unit clipping information UE7, the removal amount in the clipping target area 57 determined in the second clipping target portion determining step S106 (clipping target portion determining step) into a low-speed removal amount in which the clipping target area 57 is removed by the low-speed correction step S107A and a high-speed removal amount in which the clipping target area 57 is removed by the high-speed correction step S107B.Then, from the cutout target area 57, the low-speed removal amount, and the high-speed removal amount based on the first unit cutout information UE6 and the second unit cutout information UE7, the laser light irradiation frequency TI and the laser light scanning speed SS are determined in each of the low-speed correction step S107A and the high-speed correction step S107B.

[0097] With the above method, since the clipping condition determination step S201 includes determining the irradiation frequency TI and the scanning speed SS of each of the two pieces of unit clipping information UE (the first unit clipping information UE6, the second unit clipping information UE7) that differ from each other in scanning speed SS as the irradiation frequency TI and the scanning speed SS in the second balance correction step S107, it is possible to change the laser light scanning speed SS in the second balance correction step S107. Thus, the imbalance can be quickly removed by scanning with the laser light at the first scanning speed SS6, which is lower than the second scanning speed SS7, and it is possible to suppress the increase in the cycle time.Furthermore, by scanning with the laser light at the second scanning speed SS7, which is higher than the first scanning speed SS6, it is possible to ensure the imbalance removal accuracy.

[0098] In a particular embodiment, the low-speed removal amount described above is greater than the high-speed removal amount described above. In this case, it is possible to quickly remove the imbalance.

[0099] In some embodiments, as in Fig. 12, the second balance correction step S107 includes the above-described low-speed correction step S107A (former half-correction step) and the above-described high-speed correction step S107B (latter half-correction step) performed after the low-speed correction step S107A.

[0100] With the above method, since the balance correction in the second balance correction step S107 has the relationship between the laser light irradiation frequency TI and the laser light scanning speed SS of the laser marking device 8 and the unit removal amount UR serving as the removal amount per unit area that is weakened with the increase of the cutting depth, it is possible to suppress the reduction of the imbalance removal accuracy by scanning with the laser light at the second scanning speed SS7 which is higher than the first scanning speed SS6 in the latter half correction step.

[0101] In some embodiments, the laser marker device 8 described above has the above-described maximum laser light output of not more than 100 W. In this case, since the laser marker device 8 has the maximum laser light output of not more than 100 W, it is possible to reduce the removal amount from the turbine wheel 5 per scan, thereby enabling accurate removal by the desired removal amount by repeatedly scanning the cutout target area 57. Furthermore, since the laser marker device 8 whose maximum laser light output is not more than 100 W is cheaper than a laser marker device whose maximum laser light output exceeds 100 W, it is possible to suppress the increase in equipment costs. In particular, since the turbine wheel 5 of the small turbocharger 2 for an automobile or the like is small, the maximum laser light output is preferably not more than 50 W.Preferably, the maximum laser light output is not less than 15 W and not more than 50 W.

[0102] The method for manufacturing the turbocharger 2 according to some embodiments includes the rotor balance adjustment method 1 described above. In this case, since the balance of the rotor 3 of the turbocharger 2 is precisely adjusted in the rotor balance adjustment method 1, it is possible to suppress the vibration and noise caused during rotation of the rotor 3.

[0103] The turbocharger 2 according to some embodiments includes the rotor 3 in which the turbine wheel 5 and the compressor wheel 6 are connected via the rotary shaft 4. Then, as in Fig. 2, the turbine wheel 5 described above has the laser marking 58 engraved on the circumferential surface 551 of the hub portion 55 by the 8.

[0104] With the above configuration, since the turbocharger 2 has the laser mark 58 engraved on the peripheral surface 551 of the hub portion 55 of the turbine wheel 5 by the laser marker device 8, the balance of the rotor 3 has already been accurately adjusted, and it is possible to suppress the vibration and noise caused during the rotation of the rotor 3. For example, it is possible to accurately remove the imbalance by repeatedly irradiating the peripheral surface 551 of the hub portion 55 of the turbine wheel 5 with laser light from the laser marker device 8, making it possible to improve the accuracy of the balance adjustment of the rotor 3. Furthermore, since the laser marker device 8 is cheaper than the laser processing machine for metal processing, it is possible to suppress the increase in equipment costs.

[0105] Furthermore, in the illustrated embodiment, as shown in Fig. 4, Fig. 5, the turbine wheel 5 has a cut mark 59 cut into the end surface 552 of the hub portion 55 to remove the imbalance. In this case, the balance of the turbine wheel 5 alone has already been precisely adjusted, and it is possible to suppress the vibration and noise caused during the rotation of the rotor 3.

[0106] Furthermore, in the illustrated embodiment, as shown in Fig. 2, the turbocharger 2 has a compressor-side cut mark 26 cut into the outer surface 212 of the nut member 21 and / or the outer peripheral surface 62 of the hub 61 of the compressor wheel 6 to remove the imbalance. In this case, the balance of the rotor 3 in the cartridge 20 has already been precisely adjusted, and it is possible to suppress the vibration and noise caused during rotation of the rotor 3.

[0107] The present disclosure is not limited to the above-described embodiments, and also includes an embodiment obtained by modifying the above-described embodiments and an embodiment obtained by combining these embodiments as needed.

[0108] The content described in some embodiments described above would be understood, for example, as follows.

[0109] 1) The balance adjustment method (1) for a rotor according to at least one embodiment of the present disclosure is a balance adjustment method for a rotor (3) in which a turbine wheel (5) and a compressor wheel (6) are connected via a rotary shaft (4), comprising an imbalance detection step (second imbalance detection step S105) for detecting an imbalance position and an amount of the above-described rotor (3) after a first balance correction step (step S104) for correcting a balance of the above-described rotor (3) by cutting at least one of the above-described compressor wheel (6) and a nut member (21) connecting the above-described compressor wheel (6) to the above-described rotary shaft (4), a section for determining a cut-out target section (second cut-out target section determination section S106) for determining,based on the imbalance position and amount of the above-described rotor (3) detected in the above-described imbalance detection step (second imbalance detection step S105), a cutout target area (57) comprising an imbalance correction position (P1) of the above-described turbine wheel (5) and a distance amount in the above-described cutout target area (57), and a second balance correction step (S107) for correcting the balance of the above-described rotor (3) by repeatedly irradiating the above-described cutout target area (57) determined in the above-described cutout target section determination section (second cutout target section determination section S106) with laser light from a laser marker device (8) to remove the above-described distance amount from the above-described turbine wheel (5).

[0110] With the above method 1), the second balance correction step includes correcting the balance of the above-described rotor by repeatedly irradiating the cutout target area with the laser light from the laser marking device to remove the imbalance from the turbine wheel by the above-described removal amount. Herein, the above-described laser marking device has a smaller laser light output than a laser processing machine for metal processing and can reduce the removal amount from the turbine wheel per scan in the cutout target area. Thus, accurate removal by a desired removal amount is possible by repeatedly scanning the cutout target area. That is, the above-described laser marking device is suitable for finely adjusting the balance of the rotor in the second balance correction step.Furthermore, the laser marking device described above can accurately process the turbine wheel, even if the turbine wheel is made of a material that is difficult to cut. Thus, with the above method, it is possible to improve the accuracy of rotor balance adjustment. Furthermore, since the laser marking device described above is cheaper than the laser processing machine for metal processing, it is possible to suppress the increase in equipment costs.

[0111] 2) In some embodiments, in the balance adjustment method (1) for the rotor according to the above method 1), the above-described cutout target area (57) is located on a circumferential surface (551) of a hub portion (55) of the above-described turbine wheel (5).

[0112] With the above method 2), the cutout target area is located on the peripheral surface of the hub portion of the turbine wheel. To remove a portion of the turbine wheel as an imbalance from the cutout target area located on the peripheral surface of the hub portion, the laser light of the laser marker device is emitted along a direction that intersects with (e.g., orthogonal to) the axial direction of the turbine wheel. Here, the hub portion of the turbine wheel has a smaller centrifugal force generated during rotation of the turbine wheel than the hub (51) and the blades (53), which makes it possible to reduce an adverse effect (such as a decrease in high-cycle fatigue strength) due to the removal processing in the cutout target area. Then, since the peripheral surface of the hub portion has a longer distance from the rotational center axis (RC) of the hub portion (turbine wheel) than the end surface (552) of the hub portion, it is possible to reduce the amount of removal required to eliminate the imbalance. Furthermore, the end surface of the hub portion is cut off alone at the time of balancing in the turbine rotor, and it may be impossible to secure a sufficient cutting allowance. However, the peripheral surface of the hub portion can ensure a sufficient cutting allowance even if the amount of removal is large.

[0113] 3) In some embodiments, the balance adjustment method (1) for the rotor according to the above method 1) or 2) further comprises a cutout condition determination step (S201) of determining, with reference to at least one piece of unit cutout information (UE), an irradiation frequency (TI) of the above-described laser light and a scanning speed (SS) of the above-described laser light of the above-described laser marker device (8) are associated with a unit removal amount (UR), which is a removal amount per unit area, the above-described irradiation frequency (TI) of the above-described laser light and the above-described scanning speed (SS) of the above-described laser light in the above-described second balance correction step (S107) from the above-described cutout target area (57) and the above-described removal amount,which were determined in the above-described clipping target section determination step (second clipping target section determination step S106).

[0114] With the above method 3), based on the relationship (unit cutout information) between the laser light irradiation frequency and the laser light scanning speed of the laser marker device and the unit removal amount, which is the removal amount per unit area, the laser light irradiation frequency and the laser light scanning speed are determined in the second balance correction step from the cutout target range and the removal amount determined in the cutout target portion determination step. In this case, a difference between the removal amount determined in the cutout target portion determination step and an actual amount removed in the second balance correction step can be reduced, making it possible to remove the imbalance of the turbine wheel (5) by an appropriate amount.Thus, with the above method, it is possible to improve the accuracy of the balance adjustment of the rotor (3).

[0115] 4) In some embodiments, in the balance adjustment method (1) for the rotor according to the above method 3), the above-described at least one piece of unit cutout information (UE) includes a plurality of pieces of unit cutout information (UE) each having the above-described different scanning speed (SS) with respect to the same above-described unit removal amount, and the above-described cutout condition determining step (S201) includes determining, as the above-described irradiation frequency (TI) and the above-described scanning speed (SS) in the above-described second balance correction step, an irradiation frequency (TI) and a scanning speed (SS) of unit cutout information (UE) having the above-described highest scanning speed (SS) among the above-described plurality of pieces of unit cutout information (UE).

[0116] Although the imbalance removal amount per irradiation frequency decreases when the laser light scanning speed is increased, it is possible to reduce the difference between the expected imbalance removal amount and the actual imbalance removal amount. This means that it is possible to improve the imbalance removal accuracy. In contrast, when the laser light scanning speed is decreased, although the difference between the expected imbalance removal amount and the actual imbalance removal amount increases compared to the case where the scanning speed is high, it is possible to increase the imbalance removal amount per irradiation frequency.With the above method 4), since the clipping condition determining step includes determining, as the irradiation frequency and the scanning speed in the second balance correction step, the irradiation frequency and the scanning speed of the unit clipping information having the highest scanning speed among the plurality of pieces of unit clipping information, it is possible to improve the imbalance removal accuracy.

[0117] 5) In some embodiments, in the balance adjustment method (1) for the rotor according to the above method 4), each scanning speed (SS) of the above-described plurality of pieces of unit clipping information (UE) is less than an upper threshold value (USS).

[0118] By increasing the laser light scanning speed, it is possible to improve the imbalance removal accuracy compared to a case where the scanning speed is low. However, as the scanning speed is increased, the imbalance removal amount per irradiation frequency (scan) decreases, which increases the irradiation frequency and increases the cycle time in the second balance correction step. The "cycle time" means a time required for the laser marker device 8 to remove the imbalance from the turbine wheel 5 by the amount required for balance adjustment in the second balance correction step. For example, in a manufacturing process of the turbocharger including the rotor, if the cycle time in the second balance correction step is longer than that in other processes, the productivity of the turbocharger decreases.With the above method 5), since the irradiation frequency and scanning speed of the unit clipping information with the highest scanning speed among the plurality of pieces of unit clipping information including the scanning speed lower than the upper threshold are determined as the irradiation frequency and scanning speed in the second balance correction step, it is possible to make the scanning speed in the second balance correction step lower than the upper threshold. Thus, it is possible to prevent the cycle time in the second balance correction step from becoming too long while improving the imbalance removal accuracy.

[0119] 6) In some embodiments, in the balance adjustment method (1) for the rotor according to the above method 3), the above-described at least one piece of unit cutout information (UE) includes a plurality of pieces of unit cutout information (UE) each having the above-described different scanning speed (SS) with respect to the same unit removal amount (UR), and the above-described cutout condition determining step (S201) includes determining, as the above-described irradiation frequency (TI) and the above-described scanning speed (SS) in the above-described second balance correction step, an irradiation frequency (TI) and a scanning speed (SS) of unit cutout information (UE) with a minimum cycle time in the above-described second balance correction step (S107) among the above-described plurality of pieces of unit cutout information (UE).

[0120] With the above method 6), since the clipping condition determining step includes determining, as the irradiation frequency and the scanning speed in the second balance correction step, the irradiation frequency and the scanning speed of the unit clipping information having the minimum cycle time in the second balance correction step among the plurality of pieces of unit clipping information, it is possible to shorten the cycle time in the second balance correction step.

[0121] 7) In some embodiments, in the balance adjustment method (1) for the rotor according to the above method 6), each scanning speed (SS) of the above-described plurality of pieces of unit clipping information (UE) is greater than a lower threshold value (LSS).

[0122] When the laser light scanning speed is reduced, the imbalance removal amount per irradiation frequency (scan) increases compared to the case where the scanning speed is high, making it possible to reduce the irradiation frequency and shorten the cycle time in the second balance correction step. However, when the scanning speed is reduced, the difference between the expected removal amount and the actual removal amount of the imbalance increases, which reduces the imbalance removal accuracy.With the above method (7), since the irradiation frequency and scanning speed of the unit cutout information with the minimum cycle time among the plurality of pieces of unit cutout information containing the scanning speed greater than the lower threshold are determined as the irradiation frequency and scanning speed in the second balance correction step, it is possible to make the scanning speed in the second balance correction step greater than the lower threshold. Thus, it is possible to ensure the required imbalance removal accuracy while shortening the cycle time in the second balance correction step.

[0123] 8) In some embodiments, in the balance adjustment method (1) for the rotor according to the above method 3), the at least one piece of unit cutout information (UE) includes a plurality of pieces of unit cutout information (UE) each having the above-described different scanning speed (SS), and the above-described cutout condition determining step (S201) includes determining, as the above-described irradiation frequency (TI) and the above-described scanning speed (SS) in the above-described second balance correction step, an irradiation frequency (TI) and a scanning speed (SS) of each of first unit cutout information (UE6) including a first scanning speed (SS6) as the above-described scanning speed (SS), and second unit cutout information (UE7) including a second scanning speed (SS7),which is higher than the above-described first scanning speed (SS6) than the above-described scanning speed (SS), among the above-described plurality of pieces of unit clipping information (UE).,

[0124] With the above method (8), since the cutout condition determination step includes determining the irradiation frequency and scanning speed of each of the two pieces of unit cutout information (the first unit cutout information UE6, the second unit cutout information UE7) that differ from each other in scanning speed as the irradiation frequency and scanning speed in the second balance correction step, it is possible to change the laser light scanning speed in the second balance correction step (S107). Thus, the imbalance can be quickly removed with the first scanning speed lower than the second scanning speed as the laser light scanning speed, making it possible to suppress the increase in the cycle time.Furthermore, with the second scanning speed being higher than the first scanning speed than the laser light scanning speed, it is possible to ensure the imbalance removal accuracy.

[0125] 9) In some embodiments, in the balance adjustment method (1) for the rotor according to the above method 8), the above-described second balance correction step (S107) includes a previous half-correction step (low-speed correction step S107A) in which the above-described scanning speed (SS) of the above-described laser light is the above-described first scanning speed (SS1), and a latter half-correction step (high-speed correction step S107B) performed after the above-described previous half-correction step (low-speed correction step S107A) in which the above-described scanning speed (SS) of the above-described laser light is the above-described second scanning speed (SS7), which is higher than the above-described first scanning speed (SS6).

[0126] With the above method 9), since the balance correction in the second balance correction step has the relationship between the laser light irradiation frequency (TI) and the laser light scanning speed of the laser marker device (8), and the unit removal amount (UR) serving as the removal amount per unit area is weakened with increasing cutting depth, it is possible to suppress the decrease in the imbalance removal accuracy by scanning with the laser light at the second scanning speed higher than the first scanning speed in the latter half correction step.

[0127] 10) In some embodiments, in the balance adjustment method (1) for the rotor according to any one of the above methods 1) to 9), the above-described cutout target area (57) is arranged on a peripheral surface (551) of a hub portion (55) of the above-described turbine wheel (5) and has a long axis (LA) along a circumferential direction of the above-described turbine wheel (5) and a short axis (SA) along an axial direction of the above-described turbine wheel (5).

[0128] With the above method 10), the cutout target area has the long axis along the circumferential direction of the turbine wheel and the short axis along the axial direction of the turbine wheel. Since the peripheral surface (551) of the hub portion (55) of the turbine wheel has a circumferential length longer than the axial length, the cutout target area having the long axis along the circumferential direction easily secures its area.

[0129] 11) In some embodiments, in the balance adjustment method (1) for the rotor according to the above method 10), a condition of 1.5 ≤ L2 / L1 ≤ 100 is satisfied, where L1 is a length of the above-described short axis (SA) and L2 is a length of the above-described long axis (LA).

[0130] If the length L2 of the long axis of the cutout target area (57) is too long, the distances from the imbalance correction position (P1) to both end portions (571, 572) of the long axis extending along the circumferential direction of the turbine wheel 5 increase, which may make the two end portions (571, 572) less effective in correcting imbalance. Furthermore, if the length L2 of the long axis of the cutout target area is too short, it may be impossible to remove the amount of removal required to eliminate the imbalance. With the above method (11), since the condition 1.5 ≤ L2 / L1 ≤ 100 is satisfied, it is possible to suppress the increase in the distances from the imbalance correction position to the two end portions of the long axis, and make the two end portions effective in correcting the imbalance throughout the entire cutout target area.Furthermore, it is possible to secure the amount of removal needed to eliminate the imbalance.

[0131] 12) In some embodiments, in the balance adjustment method (1) for the rotor according to the above method 10) or 11), the above-described cutout target region (57) includes a first cutout target region (57A) and a second cutout target region (57B) arranged along the above-described first cutout target region (57A) in the above-described axial direction of the above-described turbine wheel (5).

[0132] With the above method 12), since each of the plurality of cutout target areas (such as the first cutout target area 57A, the second cutout target area 57B) has the short axis (SA) along the axial direction of the turbine wheel, the plurality of cutout target areas (57) can be located on the peripheral surface (551) of the hub portion (55) of the turbine wheel. Furthermore, since the plurality of cutout target areas are located adjacent to each other on the peripheral surface of the hub portion of the turbine wheel in the axial direction of the turbine wheel, compared to a case where the single cutout target area (57) is located, it is possible to increase the amount of material that can be removed from the hub portion of the turbine wheel while suppressing an excessive increase in the long axis (LA) of each cutout target area.

[0133] 13) In some embodiments, in the balance adjustment method (1) for the rotor according to any one of the above methods 1) to 12), the above-described laser light of the above-described laser marker device (8) has a maximum output power of not more than 100 W.

[0134] With the above method 13), since the laser marker device has a maximum laser light output of not more than 100W, it is possible to reduce the removal amount from the turbine wheel (5) per scan, thereby enabling accurate removal by the desired removal amount by repeatedly scanning the cutout target area (57). Furthermore, since the laser marker device with a maximum laser light output of not more than 100W is cheaper than a laser marker device with a maximum laser light output exceeding 100W, it is possible to suppress the increase in equipment costs.

[0135] 14) A turbocharger (2) according to at least one embodiment of the present disclosure is a turbocharger (2) including a rotor (3) in which a turbine wheel (5) and a compressor wheel (6) are connected via a rotating shaft (4). The above-described turbine wheel (5) has a laser marking (58) engraved on a circumferential surface (551) of a hub portion (55) by a laser marker device (8).

[0136] With the above configuration (14), since the turbocharger has the laser marking engraved on the peripheral surface of the hub portion of the turbine wheel by the laser marking device, the balance of the rotor described above has already been adjusted, and it is possible to suppress the vibration and noise caused during rotor rotation. For example, it is possible to accurately remove the imbalance by repeatedly irradiating the peripheral surface of the hub portion of the turbine wheel with laser light from the laser marking device, making it possible to improve the accuracy of rotor balance adjustment. Furthermore, since the above-described laser marking device is cheaper than the laser processing machine for metal processing, it is possible to suppress the increase in equipment costs. List of reference symbols 1 Equilibrium adjustment procedure 2 turbochargers 20 cartridges 21 Nut element 22 warehouses 23 Bearing housing 24 turbine housings 25 Compressor housing 26 Compressor-side cutting mark 3 Rotor 4 rotating shaft 41 A final section 42 Another end section 43, 45 Outer peripheral surface 44 Previous section 5 Turbine wheel 50 turbine rotor 51 Hub 52 Outer peripheral surface 53 shovel 54 A final section 55 Hub section 57 Cutout target area 57A First excision target area 57B Second excision target area 58 Laser marking 59 Cutting mark 6 Compressor wheel 61 Hub 62 Outer peripheral surface 63 shovel 64 through hole 65 Front edge end 7 Imbalance detection device 71 Housing element 71A Turbine-side housing element 71B Compressor-side housing element 72 Bearing mechanism 72A Turbine-side bearing mechanism 72B Compressor-side bearing mechanism 73 Vibration isolation element 74 Pressing device 75 Rotating device 751 blower 752 Air supply pipe 76 Detection device 761 acceleration sensor 762 angle sensor 763 Calculating device 8 Laser marking device 81 Laser light irradiation part 82 Irradiation position adjustment part L axis LA Long Axis P1 Imbalance correction position RC rotation center axis RG reference vibration acceleration RT Unit Cut-Out Period Information S101 Cartridge assembly step S102 First imbalance detection step S103 First cutout target section determination step S104 First balance correction step S105 Second imbalance detection step S106 Second cutout target section determination step S107A Low-speed correction step S107B High-speed correction step S107 Second equilibrium correction step S201 Cutting condition determination step SA Short Axis SS, SS1-SS7 scan speed T trajectory TI, TI1-TI5 irradiation frequency TP laser irradiation target position UE, UE1-UE7 unit cut-out information UR, UR1 Unit distance amount UT, UT1-UT5 unit cut-out period

Claims

[1] A balance adjustment method for a rotor in which a turbine wheel and a compressor wheel are connected via a rotary shaft, comprising: an imbalance detection step of detecting an imbalance position and amount of the rotor after a first balance correction step of correcting a balance of the rotor by cutting the compressor wheel and / or a nut member connecting the compressor wheel to the rotary shaft; a cutout target portion determination step of determining, based on the imbalance position and amount of the rotor detected in the imbalance detection step, a cutout target area including an imbalance correction position of the turbine wheel and a removal amount in the cutout target area; a second balance correction step of correcting the balance of the rotor by repeatedly irradiating the cutout target area determined in the cutout target portion determination step with laser light using a laser marker device, thereby removing the removal amount from the turbine wheel; and a clipping condition determining step of determining, with reference to at least a piece of unit clipping information, an irradiation frequency of the laser light and a scanning speed of the laser light of the laser marker device are associated with a unit removal amount, which is a removal amount per unit area, the irradiation frequency of the laser light and the scanning speed of the laser light in the second balance correction step from the clipping target range and the removal amount determined in the clipping target portion determining step. [2] The balance adjusting method for a rotor according to claim 1, wherein the cutout target area is located on a peripheral surface of a hub portion of the turbine wheel. [3] The balance adjusting method for a rotor according to claim 1, wherein the at least one piece of unit cutout information includes a plurality of pieces of unit cutout information each having a different scanning speed with respect to the same unit distance amount, and wherein the cutout condition determining step includes determining, as the irradiation frequency and the scanning speed in the second balance correcting step, an irradiation frequency and a scanning speed of unit cutout information having the highest scanning speed among the plurality of pieces of unit cutout information. [4] A balance adjusting method for a rotor according to claim 3, wherein each scanning speed of the plurality of pieces of unit cutout information is less than an upper threshold. [5] A rotor balance adjustment method according to claim 1, wherein the at least one piece of unit clipping information includes a plurality of pieces of unit clipping information each having a different scanning speed with respect to the same unit distance amount, and wherein the clipping condition determining step includes determining, as the irradiation frequency and the scanning speed in the second balance correcting step, an irradiation frequency and a scanning speed of unit clipping information having a minimum cycle time in the second balance correcting step among the plurality of pieces of unit clipping information. [6] A balance adjustment method for a rotor according to claim 5, wherein each scanning speed of the plurality of pieces of unit cutout information is greater than a lower threshold. [7] A balance adjustment method for a rotor according to claim 1, wherein the at least one piece of unit clipping information includes a plurality of pieces of unit clipping information each having a different scanning speed, and wherein the clipping condition determining step includes determining, as the irradiation frequency and the scanning speed in the second balance correcting step, an irradiation frequency and a scanning speed of each of first unit clipping information including a first scanning speed as the scanning speed and second unit clipping information including a second scanning speed higher than the first scanning speed as the scanning speed, among the plurality of pieces of unit clipping information. [8] A balance adjustment method for a rotor according to claim 7, wherein the second balance correction step includes: an earlier half-correction step in which the scanning speed of the laser light is the first scanning speed; and a later half-correction step performed after the earlier half-correction step, in which the scanning speed of the laser light is the second scanning speed, which is higher than the first scanning speed. [9] The balance adjustment method for a rotor according to any one of claims 1 to 8, wherein the cutout target area is located on a circumferential surface of a hub portion of the turbine wheel, and has a long axis along a circumferential direction of the turbine wheel and a short axis along an axial direction of the turbine wheel. [10] A balance adjusting method for a rotor according to claim 9, wherein a condition of 1.5 ≤ L2 / L1 ≤ 100 is satisfied, where L1 is a short axis length and L2 is a long axis length. [11] The balance adjustment method for a rotor according to claim 9 or 10, wherein the cut-out target area includes a first cut-out target area and a second cut-out target area arranged along the first cut-out target area in the axial direction of the turbine wheel. [12] A balance adjustment method for a rotor according to any one of claims 1 to 11, wherein the laser light of the laser marker device has an output power of not more than 100 W.

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