Method for acquiring balance correction information and balance correction information acquisition device

Abstract

The method for obtaining balance correction information comprises: a step for obtaining first vibration data when rotating at a specific rotational speed without performing trial cutting; a step for obtaining second vibration data when rotating at a low-frequency rotational speed lower than the specific rotational speed without performing trial cutting; a step for obtaining third vibration data in a state in which the rotating body is rotated at a specific rotational speed after trial cutting is performed at the first correction position; using the first vibration data and the third vibration data to obtain a first influence coefficient indicating the degree of influence of trial cutting on the vibration of the rotating body; a step for obtaining radial runout information indicating the degree of runout caused by the shape of the rotating body, using the second vibration data; and a step for obtaining balance correction information using the first vibration data, the influence coefficient, and the radial run-out information.

Description

Technical Field

[0001] This disclosure relates to a method for obtaining balance correction information and an apparatus for obtaining balance correction information. Background Technology

[0002] Vibration data is obtained by measuring the vibration of a high-speed rotating body using a vibration meter. The non-uniform mass distribution around the axis of rotation of the rotating body is the cause of dynamic imbalance. The vibration data mentioned above includes vibration components caused by dynamic imbalance. Furthermore, vibration data sometimes includes vibration components caused by factors different from those caused by dynamic imbalance. For example, vibration components that appear to be vibrating due to the shape of the rotating body can be listed as factors different from those caused by dynamic imbalance. This phenomenon is called radial runout.

[0003] For example, Patent Document 1 discloses a testing apparatus for rotating equipment. The testing apparatus of Patent Document 1 determines the shape deviation of the rotating body when it is stationary as the radial runout. Furthermore, it determines the shape deviation at the operating speed based on the radial runout. By subtracting the shape deviation during operation from the vibration synchronized with the rotation generated during operation, highly accurate vibration characteristics can be obtained.

[0004] Patent Document 1: Japanese Patent Application Publication No. 7-270229

[0005] To correct the dynamic balance of a rotating body, it is necessary to accurately know the vibration components caused by the dynamic imbalance. As shown in Patent Document 1, vibration data obtained using a vibrator sometimes includes apparent vibration components caused by radial runout. As mentioned above, the apparent vibration components caused by radial runout are not the vibration components caused by the dynamic imbalance. Therefore, it is necessary to subtract the apparent vibration components caused by radial runout from the vibration data obtained using the vibrator. Several methods for subtracting the apparent vibration components caused by radial runout have been proposed, exemplified by Patent Document 1. However, in this technical field, a technique is desired that can easily obtain highly accurate balance correction information based on the vibration data after subtracting the apparent vibration components caused by radial runout. Summary of the Invention

[0006] This disclosure provides a method for obtaining high-precision balance correction information and an apparatus for obtaining balance correction information, which can easily obtain high-precision balance correction information.

[0007] One method of obtaining balance correction information disclosed herein is a method for obtaining balance correction information for correcting dynamic imbalances in a rotating body rotatably supported by a non-contact bearing and rotating around a rotation axis. The method for obtaining balance correction information includes the following steps: obtaining first vibration data along a direction intersecting the rotation axis when the rotating body is rotating at a specific speed without applying a test weight or performing a test cut; obtaining second vibration data along a direction intersecting the rotation axis when the rotating body is rotating at a low-frequency speed lower than the specific speed without applying a test weight or performing a test cut; obtaining third vibration data along a direction intersecting the rotation axis when the rotating body is rotating at a specific speed with a test weight applied or a test cut performed at a first correction position in the rotating body; obtaining a first influence coefficient representing the degree of influence of applying a test weight or performing a test cut on the vibration of the rotating body using the first vibration data and the third vibration data; obtaining radial runout information representing the degree of oscillation caused by the shape of the rotating body using the second vibration data; and obtaining balance correction information using the first vibration data, the first influence coefficient, and the radial runout information.

[0008] Other aspects of this disclosure include an apparatus for obtaining balance correction information for correcting dynamic imbalances in a rotating body rotatably supported by a non-contact bearing and rotating around a rotation axis. The apparatus for obtaining balance correction information includes: a vibration data acquisition unit that receives first vibration data, second vibration data, and third vibration data, wherein the first vibration data is vibration data along a direction intersecting the rotation axis when the rotating body rotates at a specific speed without applying a test weight or performing a test cut; the second vibration data is vibration data along a direction intersecting the rotation axis when the rotating body rotates at a low-frequency speed lower than the specific speed without applying a test weight or performing a test cut; and the third vibration data is vibration data along a direction intersecting the rotation axis when a test weight is applied or a test cut is performed at a first correction position in the rotating body, and the rotating body rotates at a specific speed; an influence coefficient acquisition unit that uses the first vibration data and the third vibration data to obtain a first influence coefficient representing the degree of influence of applying a test weight or performing a test cut on the vibration of the rotating body; a radial runout information acquisition unit that uses the second vibration data to obtain radial runout information representing the degree of oscillation caused by the shape of the rotating body; and a balance correction information acquisition unit that uses the first vibration data, the first influence coefficient, and the radial runout information to obtain balance correction information.

[0009] According to the method and apparatus for obtaining balance correction information, radial runout information is obtained using second vibration data along the direction intersecting the rotation axis when the rotating body rotates at a low-frequency speed lower than a specific speed without applying a test weight or performing test cutting. In this way, balance correction information can be obtained even by reducing one unknown compared to the past. As a result, balance correction information can be obtained with a smaller number of measurement data. Therefore, high-precision balance correction information, including radial runout, can be easily obtained with fewer measurement data.

[0010] One method for obtaining balance correction information involves obtaining the first vibration data by applying a predetermined driving force to the rotating body, creating a forced rotation state where the rotating body rotates at a specific speed. The process of obtaining the second vibration data can also be performed after obtaining the first vibration data, by stopping the application of the predetermined driving force applied in the first vibration data acquisition process, creating a free rotation state where the rotational speed of the rotating body gradually decreases, and obtaining the second vibration data. Based on these processes, good radial runout information can be obtained.

[0011] One method for obtaining balance correction information may further include the following steps: obtaining fourth vibration data along a direction intersecting the rotation axis when a trial weight is applied or a trial cut is performed at a second correction position different from the first correction position in the rotating body, and the rotating body is rotating at a specific rotational speed; and obtaining a second influence coefficient representing the degree of influence of applying the trial weight or performing the trial cut on the vibration of the rotating body using the third and fourth vibration data. Based on these steps, so-called two-sided correction can be performed as a correction to the rotational balance.

[0012] One method for obtaining balance correction information can also be achieved at a specific rotational speed higher than the floating speed at which the rotating body rises from the bearing. The low-frequency rotational speed can also be lower than the floating speed. Based on these conditions, good radial runout information can also be obtained.

[0013] One method for obtaining balance correction information can also be achieved at a specific rotational speed higher than the critical rotational speed of the rotating body. Similarly, low-frequency rotational speeds can be lower than the critical rotational speed of the rotating body. Based on these conditions, good radial runout information can also be obtained.

[0014] According to this disclosure, a method for obtaining balance correction information and an apparatus for obtaining balance correction information are provided, which can easily obtain high-precision balance correction information. Attached Figure Description

[0015] Figure 1This diagram schematically illustrates the method for obtaining balance correction information according to the present disclosure and the balance correction information acquisition device for performing balance correction.

[0016] Figure 2 This is a diagram illustrating the main steps of the method for obtaining balance correction information according to this disclosure.

[0017] Figure 3 This is a diagram illustrating the functional structure of the balance correction information acquisition device of this disclosure.

[0018] Figure 4 This is a diagram used to illustrate the method for obtaining radial runout information. Detailed Implementation

[0019] Hereinafter, the embodiments for carrying out the present invention will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same elements are labeled with the same reference numerals, and repeated descriptions are omitted.

[0020] like Figure 1 As shown, the method for obtaining balance correction information and the balance correction information acquisition device 1 of this disclosure are used to correct the balance of a rotating body 9 rotating about a rotation axis A. The rotating body 9 has a shaft 90 and two impellers 91 and 92. The rotating body 9 is, for example, a component of a turbocharger. The rotating body 9 is supported by two journal bearings 93 and 94 and a pair of thrust bearings 95 to enable it to rotate.

[0021] Journal bearings 93 and 94 are non-contact bearings. For example, journal bearings 93 and 94 are a type of gas bearing. Journal bearings 93 and 94 float during rotation due to fluid being drawn between the shaft 90 and the inner circumferential surface of the bearing. At speeds higher than the specified floating speed, the rotating body 9 does not make physical contact with journal bearings 93 and 94.

[0022] The thrust bearing 95 is also a non-contact bearing. For example, the thrust bearing 95 could also be a foil bearing using corrugated foil. When the shaft 90 rotates at a speed higher than the specified speed, a fluid film forms between the thrust ring 96 and the thrust bearing 95. Therefore, when the shaft 90 rotates at a speed higher than the specified speed, the rotating body 9 does not physically contact the thrust bearing 95.

[0023] For the rotating body 9, when there is a deviation in the mass distribution around the axis of rotation A, the centrifugal force corresponding to the deviation in mass acts periodically. That is, the rotating body 9 sometimes vibrates at a frequency corresponding to the rotational speed.

[0024] When the rotating body 9 is rotated about the rotation axis A, due to the non-uniformity of its shape relative to the rotation axis A, periodic displacement changes with a frequency corresponding to the rotational speed are captured by displacement sensors 21 and 22. Therefore, it appears as if the rotating body 9 is vibrating. This apparent vibration is called radial runout.

[0025] When the rotating body 9 rotates, the periodic displacement information captured by displacement sensors 21 and 22 includes components caused by dynamic imbalance and components caused by radial runout. The purpose of balance correction for the rotating body 9 is to reduce the components caused by dynamic imbalance. Therefore, if the outputs of displacement sensors 21 and 22 include components caused by radial runout, there is a tendency for the accuracy of balance correction to decrease. The method for obtaining balance correction information and the balance correction information acquisition device 1 disclosed herein suppress the influence of radial runout and obtain good balance correction information.

[0026] If the rotating body 9 is rotated at an extremely low speed, the centrifugal force becomes smaller. Therefore, the magnitude of the component caused by dynamic imbalance becomes smaller. On the other hand, the component caused by radial runout is due to the shape of the rotating body 9, and therefore its magnitude is not affected by the rotational speed. Therefore, in order to deduce the component caused by radial runout, consider rotating the rotating body 9 at an extremely low speed.

[0027] However, as described above, the rotating body 9, which is the object of this disclosure, is supported by non-contact journal bearings 93 and 94. In order for the journal bearings 93 and 94 to be in a non-contact rotating support state, the rotational speed of the rotating body 9 must be higher than the specified upward speed. That is to say, by rotating the rotating body 9 at an extremely low speed, it is difficult to infer the component caused by radial runout.

[0028] Assume that the rotating body 9 is supported by a contact-type bearing such as a rolling bearing. In this case, the vibration of the rotating body 9 is transmitted to the bearing, and then to the housing on which the bearing is mounted. Therefore, the vibration of the rotating body 9 supported by a contact-type bearing such as a rolling bearing can be indirectly captured by a sensor mounted on the housing.

[0029] However, as repeatedly stated, the rotating body 9, which is the object of this disclosure, is supported by non-contact journal bearings 93 and 94. Vibrations of the rotating body 9 are difficult to transmit to the housing, etc., via the journal bearings 93 and 94 and the thrust bearing 95. Therefore, the vibrations of the rotating body 9, which is the object of this disclosure, can be measured with high precision using non-contact displacement sensors 21 and 22 and a rotation pulse sensor 23.

[0030] The method for obtaining balance correction information and the balance correction information acquisition device 1 disclosed herein are applied to balance correction under such special conditions, and can obtain good balance correction results through a simple method. The method for obtaining balance correction information and the balance correction information acquisition device 1 disclosed herein will be described in detail below.

[0031] [Methods for correcting the balance]

[0032] Reference Figure 2 The method for correcting the balance is described herein. The method for obtaining balance correction information disclosed herein is used for correcting the balance. Balance correction information is needed to correct the balance of the rotating body 9. The method for obtaining balance correction information disclosed herein acquires balance correction information for correcting the balance. The method for correcting the balance mainly includes: measuring the movement of the rotating body 9, obtaining balance correction information using the measured data, and correcting the movement of the rotating body 9 based on the balance correction information.

[0033] A driving force is applied to the rotating body 9, causing it to rotate at a specific speed (S10). In step S10, no trial cutting is performed on the rotating body 9. No trial weight is applied in step S10. For the state of step S10, the driving force is applied, maintaining the specific speed even after time has elapsed. The state of step S10 can also be described as a forced rotation state. Therefore, the first condition is defined by elements such as "no trial cutting is performed, and no trial weight is applied," "a driving force is applied," and "it is a specific speed." The specific speed can, for example, be the speed at which the rotating body 9 operates stably. At the specific speed, the rotating body 9 is supported in a non-contact state by the journal bearings 93 and 94 and the thrust bearing 95. That is, the rotating body 9 floats. Therefore, the specific speed is higher than the floating speed.

[0034] Next, first vibration data V1 based on the first condition is obtained (S11). This step S11 is performed by displacement sensors 21 and 22, rotation pulse sensor 23, and balance correction information acquisition device 1. In the step S11 of obtaining the first vibration data, it is not necessary to continuously apply driving force. The purpose of applying driving force is to maintain a specific rotational speed. Therefore, if it is a state in which a specific rotational speed is maintained even after time has passed, it can be a state in which driving force is applied. For example, the period of obtaining the first vibration data can also alternate between the period of applying driving force and the period of stopping driving force.

[0035] Next, stop applying the driving force to the rotating body 9 (S12).

[0036] Next, second vibration data V2 based on the second condition is obtained (S13). This step S13 is also performed by displacement sensors 21 and 22, rotation pulse sensor 23, and balance correction information acquisition device 1. Unlike step S11, no driving force is applied during the acquisition of the second vibration data. As a result, the rotational speed gradually decreases over time. In other words, the state of step S13 can also be described as a free rotation state. Therefore, the second condition is defined by elements such as "no trial cutting is performed, and no trial weight is applied," "no driving force is applied," and "the rotational speed gradually decreases." After obtaining the second vibration data V2, the rotation of the rotating body 9 is completely stopped.

[0037] The rotational speed at which the second vibration data V2 is obtained is lower than a specific rotational speed. In the following explanation, for convenience, the rotational speed at which the second vibration data V2 is obtained will be referred to as the "low-frequency rotational speed." For example, the low-frequency rotational speed can also be a value predetermined by a preliminary test. The low-frequency rotational speed can also be a value lower than the critical rotational speed of the rotating body 9. If the floating speed of the journal bearings 93 and 94 is known, a value near the floating speed can be set as the low-frequency rotational speed. That is, a value slightly higher than the floating speed can be set as the low-frequency rotational speed. A value equal to the floating speed can be set as the low-frequency rotational speed. A value slightly lower than the floating speed can be set as the low-frequency rotational speed.

[0038] From another perspective, a low-frequency rotational speed is preferably the lowest possible speed. The rotational speed of a low-frequency rotational speed does not need to be constant, but sudden changes in rotational speed are preferable. The low-frequency rotational speed simply needs to be the lowest possible speed that allows the rotating body 9 to rotate smoothly.

[0039] Next, radial runout information is obtained (S14). This step S14 is performed by the balance correction information acquisition device 1. The specific processing of obtaining radial runout information performed by the balance correction information acquisition device 1 will be described later.

[0040] Next, third vibration data V3 based on the third condition is obtained (S15). This step S15 is also performed by displacement sensors 21 and 22, rotation pulse sensor 23, and balance correction information acquisition device 1. A trial cut is performed on the rotating body 9. In step S15, the portion of the rotating body 9 corresponding to the first axial position is cut. A driving force is applied to the rotating body 9 after the trial cut, causing the rotating body 9 to rotate at a specific speed. The rotation state in step S15 is the same as in step S11, except that the trial cut is performed on the rotating body 9. Therefore, the third condition is defined by elements such as "the portion of the rotating body 9 corresponding to the first axial position is cut through the trial cut", "a driving force is applied", and "a specific speed". After obtaining the third vibration data V3, the rotation of the rotating body 9 is completely stopped.

[0041] Next, fourth vibration data V4 based on the fourth condition is obtained (S16). This step S16 is also performed by displacement sensors 21 and 22, rotation pulse sensor 23, and balance correction information acquisition device 1. A trial cut is also performed in this step S16. For the trial cut in step S16, the portion corresponding to the second axial position, which is different from the first axial position, is cut. Then, a driving force is applied to the rotating body 9 after the trial cut, causing it to rotate at a specific speed. The rotation state in step S16 is the same as in steps S11 and S15. Compared to step S11, step S16 differs only in that the portions corresponding to the first and second axial positions are cut. Compared to step S15, the positions cut by the trial cut are different in step S16. Therefore, the fourth condition is defined by elements such as "the portions corresponding to the first and second axial positions of the rotating body 9 are cut by the trial cut" and "a specific speed." After obtaining the fourth vibration data V4, the rotation of the rotating body 9 is completely stopped.

[0042] Next, the influence coefficient is obtained (S17). Step S17 is performed by the balance correction information acquisition device 1. The specific processing of obtaining the influence coefficient performed by the balance correction information acquisition device 1 will be described later.

[0043] Next, imbalance information is obtained (S18). Step S18 is also performed by the balance correction information acquisition device 1. The specific processing of obtaining imbalance information performed by the balance correction information acquisition device 1 will be described later.

[0044] Next, the rotating body 9 is corrected (S19). Step S19 is performed by an operator. The operator corrects the rotating body 9 based on the imbalance information obtained from the balance correction information acquisition device 1. Specifically, using the imbalance information, the correction mass and the position (phase) at which the correction mass is applied are determined. The balance correction information includes the correction mass and the position at which the correction mass is applied. The method for obtaining balance correction information and the balance correction information acquisition device of this disclosure obtain information containing the correction mass and the position at which the correction mass is applied, either directly or indirectly indicating this information, as balance correction information.

[0045] Next, the modified rotating body 9 is rotated at a specific speed (S20). In step S20, the vibration of the modified rotating body 9 is measured again under the first condition.

[0046] Determine whether the vibration data result of process S20 meets the benchmark (S21). If the vibration data result of process S20 meets the benchmark (process S21: Yes), the operation to correct the balance of the rotating body 9 ends. If the vibration data result of process S20 does not meet the benchmark (process S21: No), the operation can be repeated starting from process S15.

[0047] [Balance correction information acquisition device]

[0048] The device for acquiring balance correction information 1 will be described. For example... Figure 3 As shown, the balance correction information acquisition device 1 is physically a computer. The computer's processor 10A executes a program that defines a series of processes to acquire balance correction information m using displacement data d and rotation pulse data P. As a result, several functional components constituting the balance correction information acquisition device 1 are implemented.

[0049] like Figure 3 As shown, the balance correction information acquisition device 1 receives displacement data d from displacement sensors 21 and 22. The balance correction information acquisition device 1 receives rotational pulse data P from rotational pulse sensor 23. Using the displacement data d and the rotational pulse data P, the balance correction information acquisition device 1 obtains balance correction information m. The balance correction information acquisition device 1 then displays the balance correction information m to the operator.

[0050] The balance correction information acquisition device 1 includes a vibration data acquisition unit 11, an influence coefficient acquisition unit 12, a radial runout information acquisition unit 13, and a balance correction information acquisition unit 14 as functional components. These functional components are implemented by a processor 10A executing a predetermined program. In addition to the processor 10A, the balance correction information acquisition device 1 also includes a memory 10B that stores various data required for processing these functional components. The memory 10B receives data from the functional components. Furthermore, the memory 10B transfers the stored data to the requesting functional component according to its request. Multiple functional components can also perform data transmission and reception between each other. Alternatively, multiple functional components can perform data transmission and reception indirectly via the memory 10B without performing data transmission and reception between each other.

[0051] The vibration data acquisition unit 11 receives displacement data d and rotational pulse data P. The vibration data acquisition unit 11 can also directly receive displacement data d from displacement sensors 21 and 22. The vibration data acquisition unit 11 can also receive displacement data d stored in memory 10B. The vibration data acquisition unit 11 can also directly receive rotational pulse data P from rotational pulse sensor 23. The vibration data acquisition unit 11 can also receive rotational pulse data P stored in memory 10B. The vibration data acquisition unit 11 uses the displacement data d and rotational pulse data P to acquire vibration data V. The vibration data acquisition unit 11 assigns the vibration data V to the influence coefficient acquisition unit 12, the radial runout information acquisition unit 13, and the balance correction information acquisition unit 14. The vibration data acquisition unit 11 can also output the vibration data V to memory 10B. The vibration data acquisition unit 11 performs... Figure 2 The flowchart shows the processes S11, S13, S15, and S16.

[0052] The vibration data acquisition unit 11 acquires first vibration data V1 using first displacement data d obtained according to the first condition and first rotational pulse data P. Similarly, it acquires second, third, and fourth vibration data V2 to V4 using second, third, and fourth displacement data d2 to d4 and second, third, and fourth rotational pulse data P2 to P4 obtained according to the second, third, and fourth conditions. Displacement data d is data that establishes a correlation between time and displacement. Rotational pulse data P is data that establishes a correlation between time and phase. Vibration data V is defined by the displacement (amplitude) represented by displacement data d and the phase represented by rotational pulse data P.

[0053] The influence coefficient acquisition unit 12 receives vibration data V from the vibration data acquisition unit 11. The influence coefficient acquisition unit 12 may also receive vibration data V from the memory 10B. The influence coefficient acquisition unit 12 uses the vibration data V to acquire the influence coefficient α. The influence coefficient acquisition unit 12 assigns the influence coefficient α to the balance correction information acquisition unit 14. The influence coefficient acquisition unit 12 may also assign the influence coefficient α to the memory 10B. The influence coefficient acquisition unit 12 performs... Figure 2 The flowchart shows process S17.

[0054] The influence coefficient acquisition unit 12 uses first vibration data V1 obtained from a rotating body 9 that is neither subjected to trial cutting nor to the application of trial weight, and third vibration data V3 obtained from a rotating body 9 whose portion is cut corresponding to the first axial position to obtain a first influence coefficient α (process S17a). The influence coefficient acquisition unit 12 uses third vibration data V3 obtained from a rotating body 9 whose portion is cut corresponding to the first axial position to obtain a third vibration data V3, and fourth vibration data V4 obtained from a rotating body 9 whose portion corresponding to the second axial position is cut in addition to the first axial position to obtain a fourth influence coefficient α (process S17b). The processing of obtaining the influence coefficient using vibration data obtained from a rotating body 9 that is neither subjected to trial cutting nor to the application of trial weight, and vibration data obtained from a rotating body 9 that has undergone trial cutting, can use known methods.

[0055] The radial runout information acquisition unit 13 receives second vibration data V2 from the vibration data acquisition unit 11. The radial runout information acquisition unit 13 may also receive the second vibration data V2 from the memory 10B. The radial runout information acquisition unit 13 uses the second vibration data V2 to acquire radial runout information R. The radial runout information acquisition unit 13 assigns the radial runout information R to the balance correction information acquisition unit 14. The radial runout information acquisition unit 13 may also assign the radial runout information R to the memory 10B. The radial runout information acquisition unit 13 performs... Figure 2 The flowchart shows process S14.

[0056] For example, the vibration data V at low speeds can be regarded as radial runout information. Figure 4 This is a line graph showing the vibration as the rotational speed gradually decreases from a specific speed. Vibration data can be displayed using imaginary numbers. Figure 4 In the diagram, the horizontal axis represents real numbers, and the vertical axis represents imaginary numbers. A vibration rotating at a certain speed can be represented as a point on the first trajectory T1. A vector is defined connecting the point on the first trajectory T1 to the origin. The length of the vector represents the amplitude of the vibration, and the angle of the vector represents the phase of the vibration.

[0057] For example, suppose the vibration during rotation at a certain speed is represented by point W0. In this case, the vibration data V can be represented by the length and angle (phase) of vector W1. The vibration data V represented by vector W1 includes components caused by dynamic imbalance and components caused by radial runout. (Refer to...) Figure 4 It can be seen that the vector W1 representing the vibration data V is the sum of the vector component W1a caused by dynamic imbalance and the vector component W1b caused by radial runout. The magnitude (amplitude of vibration) and phase of the vector component W1a caused by dynamic imbalance vary with the rotational speed. On the other hand, the magnitude and phase of the vector component W1b caused by radial runout are not affected by the rotational speed. The magnitude and phase of the vector component W1b caused by radial runout remain constant.

[0058] As the rotational speed decreases, the first trajectory T1 converges towards point W2. Point W2 represents the actual radial runout. However, in reality, the first trajectory T1 does not reach point W2. This is because the rotating body 9 is supported by non-contact journal bearings 93 and 94, and in the region below the floating speed, the shaft 90 contacts the journal bearings 93 and 94. Due to this contact, the vibration state of the rotating body 9 changes. The change in the vibration state of the rotating body 9 is represented by the second trajectory T2.

[0059] Therefore, point W4, where the trajectory changes from the first trajectory T1 to the second trajectory T2, is defined as a discontinuity. Furthermore, vibration data at rotational speeds near the discontinuity are treated as radial runout information R. Based on this determination of the radial runout information R, sufficiently effective results can be obtained in the dynamic balance correction.

[0060] For example, it is also possible to plot the data each time the second vibration data V2 is obtained. Figure 4 The line graph shown determines the rotational speed of the point chosen as the radial runout each time. In the case of balancing multiple rotating bodies 9, this is achieved by drawing a line graph on a particular rotating body 9. Figure 4 The line graph shown is used to determine the rotational speed of the point selected for radial runout. Furthermore, other rotating bodies 9 can also use the determined rotational speed as a low-frequency speed to obtain radial runout information R from the vibration data V corresponding to that speed.

[0061] The balance correction information acquisition unit 14 receives vibration data V from the vibration data acquisition unit 11, influence coefficient α from the influence coefficient acquisition unit 12, and radial runout information R from the radial runout information acquisition unit 13. The balance correction information acquisition unit 14 may also receive vibration data V, influence coefficient α, and radial runout information R from the memory 10B. The balance correction information acquisition unit 14 uses the vibration data V, influence coefficient α, and radial runout information R to acquire balance correction information m. The balance correction information acquisition unit 14 outputs the balance correction information m. For example, the balance correction information acquisition unit 14 may also assign the balance correction information m to the memory 10B. The balance correction information acquisition unit 14 may also display the balance correction information m via the output unit 10C constituting the balance correction information acquisition device 1. An example of the output unit 10C is a display.

[0062] Vibration data V, influence coefficient α, radial runout information R, and imbalance information are defined by the following equation (1). In equation (1), V, R, and m represent vectors. α represents a matrix.

[0063] V=αm+R …(1)

[0064] Equation (1) contains four elements. The vibration data V, the influence coefficient α, and the radial runout information R are known. The imbalance information is unknown. Therefore, by applying the vibration data V, the influence coefficient α, and the radial runout information R to Equation (1), the imbalance information can be obtained. The balance correction information m can be obtained as information that reduces the imbalance information. For example, the balance correction information m can also be obtained as information that makes the imbalance information zero.

[0065] However, rotating machinery containing the rotating body 9 sometimes cannot be removed without disassembling the rotating body 9. In this case, the balance correction of the rotating body 9 is performed while it is assembled in the stationary structure. At this time, vibration data is generally obtained from a sensor installed in the stationary structure. However, in particular, if the rotating body 9 is supported by a non-contact gas bearing, sufficient balance accuracy may not be obtained from the vibration data of the stationary structure. Therefore, a non-contact displacement sensor is used to measure the vibration of the rotating body 9. The vibration data measured by the non-contact displacement sensor includes not only the vibration component of the rotating body but also the radial runout of the vibration measuring unit. The radial runout of the vibration measuring unit includes mechanical radial runout and electromagnetic radial runout. Therefore, when performing balance correction using the vibration measurement results obtained from the non-contact displacement sensor, it is necessary to determine not only the imbalance but also the radial runout. To determine the imbalance and radial runout, vibration data at two or more rotational speeds are used.

[0066] In high-speed rotating machinery where the rotating body 9 is supported by gas bearings, a gas film cannot form in the low-rotation region, thus preventing continuous operation. Furthermore, vibration data obtained when the rotating body 9 is not fully buoyed cannot be used to determine imbalance. The buoyancy speed is generally quite high. Therefore, if vibration data obtained at speeds above the buoyancy speed is desired to determine imbalance and radial runout, sufficient accuracy may not be achieved in determining radial runout.

[0067] The method for obtaining balance correction information and the balance correction information acquisition device 1 disclosed herein were made in view of the above-mentioned problems.

[0068] [Effects]

[0069] The method for obtaining balance correction information m disclosed herein includes: step S11, obtaining first vibration data V1 along the direction intersecting the rotation axis A when the rotating body 9 is rotated at a specific rotation speed without applying a test weight or performing a test cut on the rotating body 9; step S13, obtaining second vibration data V2 along the direction intersecting the rotation axis A when the rotating body 9 is rotated at a low-frequency rotation speed lower than the specific rotation speed without applying a test weight or performing a test cut on the rotating body 9; and step S15, obtaining the rotation after performing a test cut on the first correction position in the rotating body 9. The process involves obtaining third vibration data V3 along the direction intersecting the rotation axis A when the body 9 is rotating at a specific speed; step S17a, using the first vibration data V1 and the third vibration data V3, obtaining a first influence coefficient α representing the degree of influence of the trial cut relative to the first correction position on the vibration of the rotating body 9; step S14, using the second vibration data V2, obtaining radial runout information R representing the degree of sway caused by the shape of the rotating body 9; and step S18, using the first vibration data V1, the influence coefficient α, and the radial runout information R, obtaining balance correction information.

[0070] The balance correction information acquisition device 1 disclosed herein includes a vibration data acquisition unit 11, which receives first vibration data V1, second vibration data V2, and third vibration data V3. The first vibration data V1 is data along the direction intersecting the rotation axis A when the rotating body 9 rotates at a specific speed without applying a test weight or performing test cutting. The second vibration data V2 is data along the direction intersecting the rotation axis A when the rotating body 9 rotates at a low-frequency speed lower than the specific speed without applying a test weight or performing test cutting. The third vibration data V3 is data related to the first vibration data V1 received by the rotating body 9. The data obtained by the correction unit 12, which uses the first vibration data V1 and the third vibration data V3 to obtain a first influence coefficient α representing the degree of influence of the test cut relative to the first correction position on the vibration of the rotating body 9, is as follows: The radial runout information acquisition unit 13 uses the second vibration data V2 to obtain radial runout information R representing the degree of oscillation caused by the shape of the rotating body 9; and the balance correction information acquisition unit 14 uses the first vibration data V1, the influence coefficient α, and the radial runout information R to obtain balance correction information.

[0071] The method for obtaining balance correction information and the balance correction information acquisition device 1 use second vibration data V2 along the direction intersecting the rotation axis A when the rotating body 9 is rotating at a low-frequency speed lower than a specific speed without applying a test weight or performing test cutting. As a result, compared to the past, balance correction information m can be obtained even with one less unknown. That is, balance correction information m can be obtained with a small number of measurement data. Therefore, high-precision balance correction information m, including radial runout, can be easily obtained with a small amount of measurement data.

[0072] Step S11, which obtains the first vibration data V1, involves applying a predetermined driving force to the rotating body 9, creating a forced rotation state where the rotating body 9 rotates at a specific speed, thereby obtaining the first vibration data V1. Step S13, which obtains the second vibration data V2, is performed after step S11, where the application of the predetermined driving force applied in step S11 (S12) is stopped, and the rotating body 9 is placed into a free rotation state where the speed of rotation gradually decreases, thereby obtaining the second vibration data V2. According to step S13, good radial runout information can be obtained.

[0073] The method for obtaining balance correction information includes: step S16, obtaining fourth vibration data V4 along the direction intersecting the rotation axis A in the rotating body 9 when a trial cut has been performed on a second correction position different from the first correction position and the body is rotating at a specific speed; and step S17b, obtaining a second influence coefficient α representing the degree of influence of the trial cut on the vibration of the rotating body 9 using the third vibration data V3 and the fourth vibration data V4. Based on these steps S16 and S17b, so-called two-sided correction can be performed as a correction to the rotational balance.

[0074] [Variation Example]

[0075] The above describes examples of methods for obtaining balance correction information and apparatus for obtaining balance correction information. The methods for obtaining balance correction information and apparatus for obtaining balance correction information are not limited to the examples described above and can be implemented in various ways.

[0076] In steps S15 and S16, any change in mass that alters the rotational balance of the rotating body 9 is sufficient. In steps S15 and S16 of the embodiment, the change in rotational balance is achieved by cutting the rotating body 9. For example, the change in rotational balance of the rotating body 9 can also be achieved by applying a trial weight.

[0077] In the first illustrated step S15, a first test weight is applied at a first axial position. In the first illustrated step S16, a second test weight, different from the first test weight, is applied at a second axial position. In the first illustrated step S16, the counterweight applied in step S15 is not removed. According to the first illustration, in step S17a, the first influence coefficient α can be obtained using first vibration data V1 and third vibration data V3. In step S17b, the second influence coefficient α can be obtained using third vibration data V3 and fourth vibration data V4.

[0078] In the second illustrated step S15, a first test weight is applied at a first axial position. In the second illustrated step S16, a second test weight, different from the first test weight, is applied at a second axial position. In the second illustrated step S16, the counterweight applied in step S15 is removed. According to the second illustration, in step S17a, the first influence coefficient α can be obtained using first vibration data V1 and third vibration data V3. In step S17b, the second influence coefficient α can be obtained using first vibration data V1 and fourth vibration data V4.

[0079] The balance correction illustrated in the embodiment is a so-called two-sided correction. The method for obtaining balance correction information described in the embodiment can also be applied to a so-called one-sided correction. In this case, Figure 2 The process shown omits steps S16 and S17b.

[0080] The operations performed in steps S15 and S16 to change the rotational balance of the rotating body 9 can be the same or different. For example, a trial cut can be performed in step S15, and a trial weight can be applied in step S16.

[0081] For example, if the rotating body 9 is a machine integrated with a drive mechanism such as a motor, then in process S13, it is also possible to perform operation at extremely low speed and for a short time to obtain vibration data for obtaining radial runout information.

[0082] For example, in the case where the rotating body 9 is a machine that is not integrated with a drive mechanism such as a motor, the motor may be temporarily connected in step S13. Then, extremely low-speed and short-duration operation may be performed to obtain vibration data for obtaining radial runout information.

[0083] Explanation of reference numerals in the attached figures

[0084] 1… Balance correction information acquisition device; 9… Rotating body; 11… Vibration data acquisition unit; 12… Influence coefficient acquisition unit; 13… Radial runout information acquisition unit; 14… Balance correction information acquisition unit; A… Rotation axis; V1… First vibration data; V2… Second vibration data; V3… Third vibration data; m… Balance correction information; R… Radial runout information; α… Influence coefficient.

Claims

1. A method for obtaining balance correction information, comprising obtaining balance correction information for correcting dynamic imbalances in a rotating body rotatably supported by a non-contact bearing and rotating around a rotation axis, characterized in that, It has the following processes: A process for obtaining first vibration data along a direction intersecting the axis of rotation when the rotating body is rotating at a specific speed without applying a test weight or performing a test cut; A process for obtaining second vibration data along a direction intersecting the rotation axis when the rotating body is rotating at a low-frequency speed lower than the specific rotation speed without applying a test weight or performing the test cut on the rotating body; The process of obtaining third vibration data along a direction intersecting the rotation axis when the state after applying the test weight or performing the test cut to the first corrected position in the rotating body is such that the rotating body is rotating at the specific rotation speed; A process of obtaining a first influence coefficient, representing the degree of influence of applying the test weight or performing the test cut on the vibration of the rotating body, using the first vibration data and the third vibration data; The process of obtaining radial runout information representing the degree of oscillation caused by the shape of the rotating body using the second vibration data; and The process of obtaining the balance correction information using the first vibration data, the influence coefficient, and the radial runout information.

2. The method for obtaining balance correction information according to claim 1, characterized in that, The process of obtaining the first vibration data involves applying a predetermined driving force to the rotating body, thereby creating a forced rotational state in which the rotating body rotates at the specified rotational speed, and thus obtaining the first vibration data. The process of obtaining the second vibration data is performed after the process of obtaining the first vibration data. The application of the prescribed driving force given in the process of obtaining the first vibration data is stopped, and the rotational speed of the rotating body is gradually reduced to a free rotational state, thereby obtaining the second vibration data.

3. The method for obtaining balance correction information according to claim 1 or 2, characterized in that, It also includes the following processes: A process of obtaining fourth vibration data along a direction intersecting the rotation axis when the state after applying the test weight or performing the test cut to a second correction position different from the first correction position in the rotating body, and when the rotating body is rotating at the specific rotation speed; as well as The process of obtaining a second influence coefficient, representing the degree of influence of applying the test weight or performing the test cut on the vibration of the rotating body, using the third vibration data and the fourth vibration data.

4. The method for obtaining balance correction information according to claim 1, characterized in that, The specific rotational speed is higher than the upward rotational speed at which the rotating body rises from the bearing. The low-frequency rotation speed is lower than the upward rotation speed.

5. The method for obtaining balance correction information according to claim 1, characterized in that, The specific rotational speed is higher than a critical rotational speed of the rotating body. The low-frequency rotational speed is lower than the critical rotational speed of the rotating body.

6. A balance correction information acquisition device, which acquires balance correction information for correcting dynamic imbalances in a rotating body rotatably supported by a non-contact bearing and rotating around a rotation axis, characterized in that... have: The vibration data acquisition unit receives first vibration data, second vibration data, and third vibration data. The first vibration data is vibration data along the direction intersecting the rotation axis when the rotating body is rotating at a specific speed without applying a test weight or performing a test cut. The second vibration data is vibration data along the direction intersecting the rotation axis when the rotating body is rotating at a low-frequency speed lower than the specific speed without applying a test weight or performing a test cut. The third vibration data is vibration data along the direction intersecting the rotation axis when the test weight is applied to the first correction position of the rotating body or the test cut is performed, and the rotating body is rotating at the specific speed. The influence coefficient acquisition unit uses the first vibration data and the third vibration data to obtain a first influence coefficient representing the degree of influence of applying the test weight or performing the test cut on the vibration of the rotating body; The radial runout information acquisition unit uses the second vibration data to obtain radial runout information representing the degree of oscillation caused by the shape of the rotating body; and The balance correction information acquisition unit obtains the balance correction information using the first vibration data, the influence coefficient, and the radial runout information.

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