Balance correcting device for rotating body

Abstract

To reduce time and labor required for correcting the balance of a rotor.SOLUTION: A balance correction device 10 for a rotor includes a position measurement part 20 for measuring a position of a shaft 11, a first excitation part 21 for applying a load to a first bearing 14 for supporting one end of the shaft 11, and a second excitation part 22 for applying a load to a second bearing 17 for supporting the other end of the shaft 11. Further, it has a first force sensor 24 for measuring the load generated in the first bearing 14, a second force sensor 25 for measuring the load generated in the second bearing 17, and an excitation controller 23 for generating signals to be input to the first exciter 21 and the second exciter 22 based on the reference position of the shaft 11 measured by the position measurer 20. The excitation control unit 23 generates and outputs a signal reflecting the load measurement results of the first force sensor 24 and the second force sensor 25.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a device for correcting the balance of a rotating body. [Background technology]

[0002] When a rotating body rotates, a whirling force (centrifugal force) is generated around the center of rotation of the rotating body. A known method for correcting the balance of a rotating body to remove this whirling force is to repeatedly add or remove correction weights to cancel out the whirling force generated in the rotating body.

[0003] Patent Document 1 discloses a method for correcting the balance of a rotor core of a motor, which is an example of the rotating body, by calculating the centrifugal force of a test weight using two bearings that support the rotor core. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-216686 Summary of the Invention [Problem to be solved by the invention]

[0005] In the method for correcting the balance of a rotating body described in Patent Document 1, the centrifugal force caused by a test weight is calculated in two bearings that support a rotor core.

[0006] However, with the above method, the test weight must always be attached and detached to two bearings, which takes time, and it takes a lot of time and effort to correct the balance of the rotating body.

[0007] An object of the present invention is to provide a device for correcting the balance of a rotating body that can reduce the time and labor required to correct the balance of a rotating body. [Means for solving the problem]

[0008] One aspect of the present invention is a balance correction device for a rotating body fixed to a shaft that serves as the center of rotation, the device comprising: a position measurement unit that irradiates a laser onto the rotating shaft to measure the position of the shaft; a first bearing that supports one end of the shaft and a second bearing that supports approximately the longitudinal center of the shaft; a first bearing support that supports the first bearing and a second bearing support that supports the second bearing; a first vibration unit provided on the first bearing support and that applies a load to the first bearing; a second vibration unit provided on the second bearing support and that applies a load to the second bearing; a first load measurement unit that measures the load generated in the first bearing due to the rotation of the rotating body; a second load measurement unit that measures the load generated in the second bearing due to the rotation of the rotating body; and a vibration control unit that generates control signals to be input to the first vibration unit and the second vibration unit based on the position of the shaft measured by the position measurement unit, and the vibration control unit generates the control signal by reflecting the load measurement results of the first load measurement unit and the second load measurement unit.

[0009] In another aspect of the present invention, the vibration control unit variably controls at least one of the amplitude and phase of the control signal input to the first vibration unit and the second vibration unit based on the load measurement result.

[0010] In another aspect of the present invention, the bearing support has a first leg that supports the first bearing support, a second leg that supports the second bearing support, and a base that supports the first leg and the second leg. [Effects of the Invention]

[0011] According to the present invention, it is possible to reduce the time and effort required to correct the balance of a rotating body. [Brief explanation of the drawings]

[0012] [Figure 1]1 is a conceptual diagram of a device for correcting balance of a rotating body according to an embodiment of the present invention. [Figure 2] 2 is a conceptual diagram showing the structure of a main body of the device for correcting balance of a rotating body shown in FIG. 1. FIG. [Figure 3] 2 is a block diagram of a vibration control unit of the device for correcting balance of a rotating body shown in FIG. 1. FIG. [Figure 4] 4 is a signal waveform diagram showing an example of an input signal and an output signal of the vibration control unit shown in FIG. 3. [Figure 5] 2 is a graph showing an example of an output from a first bearing of the device for correcting balance of a rotor shown in FIG. 1. FIG. [Figure 6] 1. FIG. 4 is a graph showing an example of an output from a second bearing of the device for correcting balance of a rotor shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0014] The balancing apparatus for a rotating body according to the present embodiment will be described below. In the present embodiment, the balancing apparatus for a rotating body will hereinafter be simply referred to as a balancing apparatus.

[0015] 1 is a device that corrects the balance of a rotating body 13, such as a rotor core 12, mounted on an electric motor or the like, with respect to a rotation center P1. Specifically, it is a device that corrects the balance of a rotating body 13 that includes a rotor core 12 fixed to a shaft 11 that serves as the rotation center P1.

[0016] As shown in Figure 2, the main body 30 of the balance correction device 10 is configured to include a position measurement unit 20 that irradiates a laser 20a onto the rotating shaft 11 to measure the position of the shaft 11, a first bearing 14 that supports one end of the shaft 11, and a second bearing 17 that supports the shaft 11 near the longitudinal center on the opposite side of the rotor core 12 from the one end of the shaft 11.

[0017] That is, one end of shaft 11 is supported by first bearing 14, and a portion of shaft 11 near the other end, approximately in the center of the longitudinal direction, is supported by second bearing 17. Position measurement unit 20 mainly measures the radial position of shaft 11 while it is rotating. Rotor core 12 and commutator 12a are attached to the center of shaft 11. Here, a case where rotor core 12 and commutator 12a are attached will be described assuming a brushed motor, but a brushless motor may also be assumed, in which case commutator 12a is not necessary.

[0018] In this embodiment, the structure including the rotor core 12 and the commutator 12 a is also called the rotor 13 , and the shaft 11 is also considered to be a part of the rotor 13 .

[0019] The position measurement unit 20 is, for example, a tacho probe, and measures the radial position of the shaft 11 relative to the center of rotation P1 by irradiating a laser 20a onto the rotating shaft 11. Here, the radial position of the rotating shaft 11 is detected to detect the reference position of the rotor core 12.

[0020] In addition, the main body 30 of the balance correction device 10 includes a first bearing support portion 15 that supports the first bearing 14, a second bearing support portion 18 that supports the second bearing 17, a first vibration unit 21 that is provided on the first bearing support portion 15 and applies a load to the first bearing 14, and a second vibration unit 22 that is provided on the second bearing support portion 18 and applies a load to the second bearing 17.

[0021] That is, the first bearing 14 is supported by a first bearing support 15 , while the second bearing 17 is supported by a second bearing support 18 .

[0022] The first vibration unit 21 is a member that applies a load F1 to the first bearing 14, and is, for example, a piezoelectric actuator (piezoelectric element). A piezoelectric actuator is an element that vibrates when an AC voltage is applied. Here, the first vibration unit 21 applies a predetermined load to the first bearing 14.

[0023] Similarly, the second vibration applying unit 22 is a member that applies a load F2 to the second bearing 17, and is, for example, a piezoelectric actuator (piezoelectric element).

[0024] As a result, a predetermined load is applied to the shaft 11 by the first vibration unit 21 and the second vibration unit 22, and when the shaft 11 rotates in this state, a state equivalent to a state in which centrifugal force is generated is created in the rotor 13. The rotation speed of the shaft 11 is, for example, rotation speed (Ω) = 6000 rpm.

[0025] The main body 30 of the balance correction device 10 is provided with a first leg 16 that supports the first bearing support 15 and a second leg 19 that supports the second bearing support 18. The first leg 16 is provided with a first force sensor (first load measuring unit) 24 that measures the load generated on the first bearing 14 due to the rotation of the rotating body 13. Meanwhile, the second leg 19 is provided with a second force sensor (second load measuring unit) 25 that measures the load generated on the second bearing 17 due to the rotation of the rotating body 13.

[0026] The first force sensor 24 and the second force sensor 25 are sensors that measure, for example, the centrifugal force or vibration angle generated in the bearing, and may be acceleration sensors, etc. The first force sensor 24 and the second force sensor 25 are fixed to the first leg 16 and the second leg 19, respectively, with bolts 33.

[0027] The balance correction device 10 also includes a vibration control unit 23 that generates control signals to be input to the first vibration unit 21 and the second vibration unit 22 based on the reference position of the shaft 11 measured by the position measurement unit 20.

[0028] The excitation control unit 23 is, for example, a PLL (Phase-Locked Loop) board, and outputs an AC signal (control signal) of a COS wave synchronized with the signal output from the position measurement unit 20. That is, the pulse signal output from the position measurement unit 20 is input to the excitation control unit 23, and a control signal of a COS wave generated by the excitation control unit 23 is output from the excitation control unit 23, and this control signal is input to the first excitation unit 21 and the second excitation unit 22.

[0029] The vibration control unit 23 reflects the load measurement results of the first force sensor 24 and the second force sensor 25. For example, the magnitude of the vibration that will offset the centrifugal force is detected from the load measurement results. As a result, the vibration control unit 23 generates and outputs a control signal that reflects the load measurement results (including a vibration force of a magnitude that will offset the centrifugal force). The control signal output from the vibration control unit 23 is then input to the first vibration unit 21 and the second vibration unit 22.

[0030] Furthermore, based on the load measurement result, the vibration control unit 23 variably controls at least one of the amplitude and phase of the control signal input to the first vibration exciter 21 and the second vibration exciter 22. Specifically, the vibration control unit 23 may variably control either the amplitude or the phase of the control signal input to the first vibration exciter 21 and the second vibration exciter 22, or may variably control both the amplitude and the phase of the control signal. Preferably, the vibration control unit 23 variably controls both the amplitude and the phase of the control signal based on the load measurement result.

[0031] Here, a method for outputting an input pulse signal as a COS wave in excitation control unit 23 will be described. As shown in Fig. 3, a pulse signal (input pulse 23a) input to excitation control unit 23 enters phase comparator 23b. The signal output from phase comparator 23b is converted into a sawtooth wave with an UP or DN (DOWN) slope and sent to sawtooth wave generator 23c. A sawtooth wave synchronized with input pulse 23a is then output from sawtooth wave generator 23c. Furthermore, a digital comparator 23e compares the sawtooth wave output from sawtooth wave generator 23c with a midpoint 23d of the full scale of the sawtooth wave, and switches the signal to be output from sawtooth wave generator 23c depending on which is larger.

[0032] The signal output from sawtooth wave generator 23c is further phase-shifted by phase shift signal 23f, and the sawtooth wave is converted into a COS wave by COS wave converter 23g and output as a COS wave (COS wave output 23h). As a result, vibration controller 23 outputs a signal (control signal) with the same frequency as the frequency of the signal of input pulse 23a.

[0033] The excitation control unit 23 outputs an analog COS wave and inputs it to the first excitation unit 21 and the second excitation unit 22 as a control signal.

[0034] As shown in FIG. 4, the vibration control unit 23 receives a pulse signal as an input pulse 23a and outputs an analog COS wave signal as a COS wave output 23h.

[0035] The main body 30 of the balance correction device 10 is provided with a base 26 that supports the first leg 16 and the second leg 19. The base 26 is a stand that supports the main body 30 of the balance correction device 10.

[0036] Furthermore, as shown in FIG. 1, the balance correction device 10 is equipped with a position measurement unit 20, a first force sensor 24, and a second force sensor 25, a vector diagram display 31 that displays the centrifugal force acting on the rotating body 13 as a vector based on information sent from the position measurement unit 20, the first force sensor 24, and the second force sensor 25, and a PC (personal computer) 32 that stores and displays data information of the vectors displayed on the vector diagram display 31.

[0037] The balance correction device 10 also includes an amplifier 27 that amplifies the signals sent from the position measurement unit 20 to the vibration control unit 23 and the vector diagram display unit 31, an amplifier 28 that amplifies the signals of the load measurement results sent from the first force sensor 24 and the second force sensor 25 to the vector diagram display unit 31, and an amplifier 29 that amplifies the control signals sent from the vibration control unit 23 to the first vibration unit 21 and the second vibration unit 22.

[0038] As described above, in the rotating body balancing device 10 of this embodiment, instead of using a test weight, each bearing is vibrated using a piezoelectric actuator, and the vibration control unit 23 calculates an influence coefficient and generates and outputs a signal (control signal) in which a vibration force is set to cancel out the centrifugal force. At this time, the amplitude and phase of the signal (control signal) input to the piezoelectric actuator are changed to vibrate each bearing. The vibration control unit 23 also outputs a COS wave signal synchronized with the input pulse signal as a control signal, and inputs this control signal to the piezoelectric actuator to vibrate it. In other words, the vibration control unit 23 has a signal processing function capable of generating a signal that generates a vibration force synchronized with the rotation of the rotor core 12. As a result, the vibration control unit 23 outputs a signal indicating the post-vibration state of the rotating body 13 relative to the pre-vibration state, with its amplitude and phase changed.

[0039] Next, we will explain the measurement points displayed on the vector diagram display 31. The vector diagram display 31 displays the centrifugal force acting on the rotor 13 as a vector based on information sent from the position measurement unit 20, the first force sensor 24, and the second force sensor 25. Fig. 5 shows, as measurement points, the centrifugal force acting on the rotor 13 when a predetermined load is applied to the first bearing 14 by the first vibration unit 21.

[0040] Similarly, Fig. 6 displays, as measurement points, the centrifugal force applied to the rotor 13 when a predetermined load is applied to the second bearing 17 by the second vibration unit 22. Because Figs. 5 and 6 are pie charts, the angle and magnitude of the centrifugal force applied to the rotor 13 can be seen from the displayed measurement points.

[0041] 5 and 6, (0) indicates the initial measurement point A1, (1) indicates the measurement point B1 after the first balance correction, and (2) indicates the measurement point C1 after the second balance correction. The center of each pie chart is the rotation center P1 of the rotor 13. Therefore, by repeating the balance correction multiple times, the balance is corrected so that the measurement point finally coincides with or approaches the rotation center P1 for each of the first bearing 14 and the second bearing 17.

[0042] First, (0) is the initial measurement point A1, and in response to the detection results obtained by irradiating the rotating rotor 13 with laser 20a, a predetermined signal is generated by vibration control unit 23 based on a signal of the radial position serving as a reference for shaft 11 sent from position measurement unit 20, and this signal is input to first vibration unit 21 and second vibration unit 22. In this state, the centrifugal force acting on rotor 13 based on information sent from first force sensor 24 and second force sensor 25 is displayed as a vector, which is the initial measurement point A1 of (0).

[0043] Next, based on the results of this initial measurement point A1, a load that offsets the centrifugal force so that measurement point A1 approaches the center of rotation P1 is generated as a signal by vibration control unit 23 to be input to first vibration unit 21 and second vibration unit 22. This generated predetermined signal is then output as a control signal and input to first vibration unit 21 and second vibration unit 22. In this state, the centrifugal force applied to rotor 13 is again displayed as a vector based on the information sent from first force sensor 24 and second force sensor 25, resulting in measurement point B1 after the first balance correction in (1).

[0044] Next, based on the result of the measurement point B1 after this first balance correction, the vibration control unit 23 generates a signal to input a load to the first vibration unit 21 and the second vibration unit 22 that will offset the centrifugal force so that the measurement point B1 approaches the center of rotation P1 even further. Then, this generated predetermined signal is output as a control signal and input to the first vibration unit 21 and the second vibration unit 22. In this state, the centrifugal force acting on the rotor 13 is again displayed as a vector based on the information sent from the first force sensor 24 and the second force sensor 25, which is the measurement point C1 after the second balance correction in (2).

[0045] In this manner, balance correction is repeated until the measurement point is as close as possible to the center of rotation P1, and balance correction is continued until the centrifugal force becomes approximately zero.

[0046] As shown in FIG. 5, in the first bearing 14, in the initial measurement (0), the measurement point A1 is far from the center of rotation P1, but in the measurement after the first balance correction (1), the measurement point B1 is closer to the center of rotation P1 than the measurement point A1, and further in the measurement after the second balance correction (2), the measurement point C1 is closer to the center of rotation P1 than the measurement point B1.

[0047] 6, in the second bearing 17, measurement point A1 is far from the center of rotation P1 in the initial measurement (0), but measurement point B1 after the first balance correction (1) is much closer to the center of rotation P1, and furthermore measurement point C1 after the second balance correction (2) almost overlaps with the center of rotation P1. Therefore, the balance correction work for the second bearing 17 is complete.

[0048] As described above, the balance adjustment is repeated for each bearing to achieve a state in which no centrifugal force is applied to the rotor 13.

[0049] According to the rotating body balance correction device of this embodiment, the rotating body 13 can be balanced without using a test weight, thereby reducing the time required to balance the rotating body 13. In other words, the time and labor required to balance the rotating body 13 can be reduced.

[0050] Specifically, the vibration control unit 23 generates and outputs a control signal so that a vibration force is generated at a predetermined angle. Therefore, the balance of the rotating body 13 is corrected without using a test weight, so there is no need to attach or detach the test weight. Since attaching or detaching the test weight requires a lot of time and effort, by eliminating the need to attach or detach the test weight, balance correction can be performed efficiently and the time required for balance correction can be shortened.

[0051] Furthermore, since the balance of the rotor 13 is corrected without using a test weight, the accuracy of the balance correction of the rotor 13 can be improved. Specifically, by changing the amplitude and phase of the signals input to the first vibration applying unit 21 and the second vibration applying unit 22 that apply a load to the bearing, the same function as changing the weight of the test weight can be obtained. Information obtained from the position detection results by the position measuring unit 20 and the detection results by the first force sensor 24 and the second force sensor 25 is reflected in the vibration control unit 23, and the amplitude and phase of the signals input to the first vibration applying unit 21 and the second vibration applying unit 22 are changed based on the results.

[0052] Therefore, the conditions for inputting signals to the first vibration applying unit 21 and the second vibration applying unit 22 in relation to the factors of balance correction can be set in detail, and the accuracy of balance correction of the rotor 13 can be improved.

[0053] The balance correction device 10 for a rotating body according to this embodiment can reduce the centrifugal force acting on the rotor core 12 of the electric motor. For example, if the electric motor is a wiper motor, the centrifugal force acting on the rotor core 12 can be reduced, thereby reducing the load on the wiper motor that swings the wiper arm.

[0054] As a result, the rotational efficiency of the wiper motor can be improved, which will contribute to the United Nations' Sustainable Development Goals (SDGs), particularly Goal 7 (Ensure access to affordable, reliable, sustainable and modern energy) and Goal 13 (Take urgent action to combat climate change and its impacts).

[0055] The present invention is not limited to the above-described embodiment, and it goes without saying that various modifications are possible without departing from the spirit of the present invention. For example, in the above-described embodiment, the case where the vibration control unit 23 calculates an influence coefficient from the results of the measurement points and generates a signal (control signal) that cancels out the centrifugal force has been described, but it is also possible to calculate the influence coefficient by a PC based on the results of the measurement points, reflect this calculation result in the vibration control unit 23, and output a signal (control signal) that cancels out the centrifugal force. [Explanation of symbols]

[0056] 10: Rotor balance correction device, 11: Shaft, 12: Rotor core, 12a: Commutator, 13: Rotor, 14: First bearing, 15: First bearing support, 16: First leg, 17: Second bearing, 18: Second bearing support, 19: Second leg, 20: Position measurement unit, 20a: Laser, 21: First vibration unit, 22: Second vibration unit, 23: Vibration control unit, 23a: Input pulse, 23b: Phase comparator, 23c: Sawtooth wave generator, 23d: Midpoint of sawtooth wave full scale, 23e: Digital comparator, 23f: Phase shift signal, 23g: COS wave conversion unit, 23h: COS wave output, 24: First force sensor (first load measurement unit), 25: Second force sensor (second load measuring unit), 26: base, 27, 28, 29: amplifier, 30: main body, 31: vector diagram display, 32: PC, 33: bolt, A1, B1, C1: measurement points, F1, F2: load, P1: center of rotation

Claims

1. A balance correction device for a rotating body fixed to a shaft that serves as the center of rotation, a position measurement unit that irradiates a laser onto the rotating shaft to measure the position of the shaft; a first bearing supporting one end of the shaft and a second bearing supporting the shaft at approximately the center in the longitudinal direction; a first bearing support portion that supports the first bearing and a second bearing support portion that supports the second bearing; a first vibration unit provided on the first bearing support unit and configured to apply a load to the first bearing; a second vibration unit provided on the second bearing support unit and configured to apply a load to the second bearing; a first load measuring unit that measures a load generated in the first bearing due to rotation of the rotating body; a second load measuring unit that measures a load generated in the second bearing due to rotation of the rotating body; a vibration control unit that generates control signals to be input to the first vibration applying unit and the second vibration applying unit based on the position of the shaft measured by the position measuring unit; and The vibration control unit generates the control signal by reflecting the load measurement results of the first load measurement unit and the second load measurement unit.

2. 2. The balance correction device for a rotating body according to claim 1, The vibration control unit variably controls at least one of the amplitude and phase of the control signal input to the first vibration unit and the second vibration unit based on the load measurement result.

3. 3. The balance correction device for a rotating body according to claim 1, a first leg portion supporting the first bearing support portion; a second leg portion supporting the second bearing support portion; a base supporting the first leg and the second leg; A balancing device for a rotating body having the above structure.

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