JP4824491B2 - Air gap eccentricity measuring apparatus for motor and air gap eccentricity measuring method - Google Patents

Description

  The present invention relates to an air gap eccentricity measuring device and an air gap eccentricity measuring method for an electric motor.

  Generally, in an electric motor, there is an air gap between the rotor and the stator. If this air gap is biased, the magnetic attraction force acting on the rotor changes due to the amount of eccentricity during operation of the motor, causing the rotor to vibrate. Therefore, it becomes a factor such as efficiency and torque characteristic deterioration, vibration and noise generation, and bearing deterioration. In particular, when this electric motor is used for a compressor, problems such as deterioration of the function of the compressor and defective products occur. Therefore, it is necessary to always check how much eccentricity is generated in the air gap of the electric motor.

  Therefore, conventionally, an electric motor is operated, vibration is detected by a piezoelectric pickup during the operation, a specific frequency component is extracted by the vibration detection, and the level of the component is measured. There has been proposed a technique for determining (see, for example, Patent Document 1).

  In another conventional technique, when power is supplied from an AC power source to the induction motor, if the generated torque of the induction motor is smaller than the starting torque of the compressor, the induction motor does not start and the rotor is locked. Therefore, paying attention to this fact, the maximum suction direction by the main winding of the induction motor and the phase angle direction of 90 degrees with respect to this maximum suction direction are generated. Determine the strength and direction of vibration by wearing vibration detection sensors and observing the rise of the vibration signal generated in the locked state before the rotation of the induction motor obtained by each vibration detection sensor. Thus, there has been proposed an apparatus in which the amount of eccentricity and direction of the air gap of the rotor portion of the induction motor is measured (see, for example, Patent Document 2).

JP 47-19301 A JP-A-6-284655

  By the way, in the former prior art described in Patent Document 1, although the amount of eccentricity of the air gap can be measured, there is no mechanism for measuring the direction of eccentricity of the air gap, so the direction of eccentricity of the air gap cannot be obtained.

  On the other hand, in the latter prior art described in Patent Document 2, it is possible to measure the eccentric direction of the air gap as well as the eccentric amount of the air gap, but when measuring the eccentric direction of the air gap, the vibration waveform detected by the acceleration sensor Since the vibration direction is determined by observing the rising edge of the waveform, the waveform actually measured is likely to be disturbed by the influence of external disturbances such as mechanical vibration and electrical noise, and the vibration direction can be determined. difficult. Therefore, a highly accurate vibration waveform measurement system for removing the influence of disturbance is required, and the entire apparatus is expensive.

  The present invention has been made to solve the above-described problems, and can accurately measure the eccentric state (the amount of eccentricity and the direction of eccentricity) of the air gap of the electric motor without requiring a highly accurate vibration waveform measuring system. An object of the present invention is to provide an air gap eccentricity measuring device and an air gap eccentricity measuring method for an electric motor.

An electric air gap eccentricity measuring apparatus for an electric motor according to the present invention is an apparatus for measuring the eccentricity of an air gap between a rotor and a stator of an electric motor,
An installation base capable of fixing the whole motor in a plurality of postures rotated about the main shaft in a horizontal orientation of the main shaft of the rotor, and vibration for measuring a vertical vibration amount of the motor when the rotor is rotated And a measuring means .

  In addition, the air gap eccentricity measuring method of the present invention includes a positioning step of positioning and positioning the electric motor so that the main shaft of the rotor is horizontal, and the amount of vibration in the vertical direction of the electric motor while the rotor is rotationally driven after positioning The vibration amount measurement step to be measured and the measurement position are sequentially rotated by rotating the whole motor so that each position on two virtual axes orthogonal to each other about the main axis of the rotor is set as a vibration amount measurement position. A measurement position changing step to be changed, and each of the above steps is sequentially repeated until the entire electric motor makes one round around the main shaft of the rotor, and based on each vertical vibration amount obtained at each measurement position. It is characterized in that an eccentric amount and an eccentric direction of the air gap of the electric motor are obtained.

  According to the present invention, when the main shaft of the rotor is installed horizontally, when the air gap is eccentric, not only the unbalanced magnetic attractive force due to the eccentricity but also the excitation force applied with gravity acts on the rotor. Therefore, the entire electric motor is sequentially rotated until it makes one rotation around the main axis of the rotor so that each position on two virtual axes orthogonal to each other about the main axis of the rotor is set as a measurement position of the vibration amount. By changing the measurement position of the vibration amount and measuring the magnitude of vibration in the vertical direction during operation of the electric motor at each measurement position, both the eccentric amount and the eccentric direction of the air gap can be obtained with high accuracy. Therefore, a highly accurate vibration waveform measurement system as in the prior art is not required and can be realized at low cost.

Embodiment 1 FIG.
FIG. 1 is a longitudinal sectional view of a compressor equipped with a single-phase induction motor to be measured for air gap eccentricity, and FIG. 2 is a sectional view taken along line AA in FIG.

  The compressor 1 includes a single-phase induction motor (hereinafter simply referred to as an electric motor) 2, and the electric motor 2 is disposed in a shell 3 that is a pressure vessel. An air gap 6 that is a cylindrical space is formed between the rotor 4 and the stator 5 constituting the electric motor 2.

  The stator 5 is provided with a main winding 10 and an auxiliary winding 11. The stator 5 is shrink-fitted and fixed to the inner wall of the shell 3. Further, the rotor 4 is integrally fixed to the main shaft 12 by shrink fitting, and the main shaft 12 is rotatably supported by a slide bearing (not shown) included in the frame 13 and the cylinder head 14. The frame 13 and the cylinder head 14 are fixed to the cylinder 15 with bolts (not shown), and the cylinder 15 is fixed by welding at three locations along the circumferential direction of the shell 3 (only one location is illustrated).

  A connection terminal 16 for supplying current to the main winding 10 and the auxiliary winding 11 of the stator 5 is welded and fixed to the upper part of the shell 3, and a discharge pipe 17 for discharging compressed gas to the outside is fixed by brazing. ing. Further, a muffler 18 as a gas inlet before compression is fixed to the peripheral side portion of the shell 3 by brazing. Further, the bottom portion of the shell 3 is provided with leg portions projecting radially outward at three locations along the circumferential direction, and a reference hole 20 is formed in each foot portion 19.

  In this compressor 1, the uncompressed gas is sucked from the muffler 18, then introduced into the cylinder 15, where it is compressed, and then discharged from the frame 13 into the shell 3. It passes through and is discharged to the outside of the shell 3.

  FIG. 3 is a front sectional view showing a schematic configuration of the air gap eccentricity measuring apparatus according to Embodiment 1 of the present invention, and FIG. 4 is a side sectional view of the apparatus.

  In the air gap eccentricity measuring apparatus 30 of the first embodiment, a pair of left and right mounting tables 32 on which the compressor 1 is installed are fixed on the upper surface of the base 31 so that the main shaft 12 of the rotor 4 of the electric motor 2 is horizontal, In addition, horizontality adjusters 33 are attached to the four corners of the lower surface of the base 31. Each mounting table 32 has a V-shaped upper surface cut out so that the shell 3 of the compressor 1 can be stably mounted, and vibrations between the mounting table 32 and the compressor 1 are formed on the upper surface. A vibration isolating material 34 made of rubber or the like for preventing transmission is fixed.

  Further, a support column 35 is erected vertically at the end of the base 31, and a beam 36 is fixed horizontally to the support column 35 so as to be positioned above the mounting table 32. The acceleration pickup cylinder 37 is fixed so as to be extendable and contractable along the vertical direction. An acceleration pickup 39 for vibration detection is attached to the lower end of the acceleration pickup cylinder 37 via a vibration isolator 38. As a result, the acceleration pickup 39 moves up and down in the vertical direction as the acceleration pickup cylinder 37 is expanded and contracted. The acceleration pickup cylinder 37, the vibration isolating material 38, and the acceleration pickup 39 correspond to the vibration measuring means in the claims.

  A flat plate 40 is erected vertically on the base 31 so as to be orthogonal to the main shaft 12 of the rotor 4 when the electric motor 2 is mounted on the mounting table 32. A plurality of positioning holes 41 for determining the vibration measurement position of the compressor 1 are formed.

  That is, by inserting the positioning pin 42 into the predetermined positioning hole 41 through the reference hole 20 of the foot 19, each measurement position by the acceleration pickup 39 can be reliably determined.

  Next, a method for measuring an eccentric state (an eccentric amount and an eccentric direction) of the air gap 6 of the electric motor 2 using the apparatus 30 will be described with reference to a flowchart shown in FIG. In addition, the code | symbol S means each process step.

  First, an AC power source (not shown) is connected to the connection terminal 16 (S1). Next, after the compressor 1 is installed on the vibration isolator 34 so that the main shaft 12 of the rotor 4 is horizontal, the positioning pin 42 is inserted into the reference hole 20 and the positioning hole 41 of the foot portion 19, After the alignment, the positioning pins 42 are removed (S2).

Next, energization of the compressor 1 is started to rotate the rotor 4, and in this state, the acceleration pickup 39 is lowered by the acceleration pickup cylinder 37 and pressed against the outer peripheral portion of the shell 3 of the compressor 1 (S3). And the magnitude | size of the vibration of the perpendicular direction in the outer peripheral part of the shell 3 at the time of rotation of the rotor 4 is measured by the acceleration pick-up 39 (S4). The magnitude of the vibration obtained by measuring this time is .delta.a _1.

  Next, the energization of the compressor 1 is stopped to stop the rotation of the rotor 4, and the acceleration pickup 39 is raised by the acceleration pickup cylinder 37 to be separated from the outer peripheral portion of the shell 3 of the compressor 1 (S5). Subsequently, after the compressor 1 as a whole is rotated 180 degrees in the circumferential direction around the main shaft 12 of the rotor 4, the direction is accurately determined by the positioning hole 41 different from the case of S2 (S6).

Next, energization of the compressor 1 is started and the rotor 4 is rotated. In this state, the acceleration pickup 39 is lowered by the acceleration pickup cylinder 37 and pressed against the outer peripheral portion of the shell 3 of the compressor 1 (S7). And the magnitude | size of the vibration of the perpendicular direction in the outer peripheral part of the shell 3 at the time of rotation of the rotor 4 is measured by the acceleration pick-up 39 (S8). The magnitude of vibration obtained by measurement at this time is defined as δb ₁ .

Next, it is determined whether or not the number of times n of measuring the magnitude of vibration satisfies a preset number of times k (in this example, k = 4) (S9), and the number of times of measurement n does not meet the number of times k. When (when n <k), the compressor 1 is de-energized to stop the rotation of the rotor 4 and the acceleration pickup 39 is raised by the acceleration pickup cylinder 37 to start from the outer periphery of the shell 3 of the compressor 1. Then, the entire compressor 1 is rotated by a predetermined angle (90 degrees in the first embodiment) (S10). And it returns to S2 and repeats S2-S8. When this measurement is repeated, the magnitudes of vibrations obtained in S4 and S8 are denoted by δa ₂ and δb ₂ .

Thus, when the four measurement values δa ₁ , δb ₁ , δa ₂ , and δb ₂ of the magnitude of vibration are obtained, the number of times of measurement n (= 4) satisfies the preset number of times k (= 4) in S9. Therefore (n ≧ k), the eccentric state (the eccentric amount and the eccentric direction) of the two-dimensional air gap 6 is calculated based on the above four measured values δa ₁ , δb ₁ , δa ₂ , δb _2. (S11).

Next, a method of determining the eccentric state (the eccentric amount and the eccentric direction) of the two-dimensional air gap 6 based on the four measured values δa ₁ , δb ₁ , δa ₂ , and δb ₂ in S11 will be described with reference to FIGS. This will be described with reference to the explanatory diagram shown in FIG.

  FIG. 6A shows an initial state when the compressor 1 is installed and the magnitude of vibration is measured, and FIG. 6B shows a state where the entire compressor 1 is rotated 180 degrees from the state of FIG. Each shows the state when the magnitude of vibration is measured after installation.

  When the main shaft 12 of the rotor 4 is installed in a horizontal state and an alternating current is passed, if the air gap 6 is eccentric, an unbalanced magnetic attractive force Fm is generated at the eccentric position (location where the gap is narrow). At the same time, gravity acts on the rotor 4 vertically downward.

  6A, when the eccentric position of the air gap 6 happens to be above the center of the electric motor 2, the rotor 4 has unbalanced magnetic attractive force Fm and gravity Fg caused by the eccentricity of the air gap 6. Difference ΔFa (= Fm−Fg) works vertically upward as an excitation force. On the other hand, in FIG. 6B, since the entire compressor 1 is installed after being rotated 180 degrees, the eccentric position of the air gap 6 exists below the center of the electric motor 2. Therefore, the sum ΔFb (= −Fm−Fg) of the unbalanced magnetic attractive force Fm and the gravity Fg caused by the eccentricity of the air gap 6 acts on the rotor 4 vertically downward as an excitation force.

  Thus, in the state before and after rotating the entire compressor 1 by 180 degrees, the direction of gravity does not change, whereas the eccentric position of the air gap 6 rotates by 180 degrees. Is the difference ΔFa between the unbalanced magnetic attractive force Fm and the gravity Fg as described above, and the case where the difference ΔFb is the unbalanced magnetic attractive force Fm and the gravity Fg. Accordingly, since the vibration becomes larger when the excitation force is larger, the state where the vibration is large becomes the state shown in FIG.

Then, for example, the magnitude of vibration in the state shown in FIG. 6A is the above measured value δa _1, and the magnitude of vibration measured in the state shown in FIG. 6B is the above measured value δb _1. Then, δa ₁ corresponds to the magnitude of vibration measured when the excitation force ΔFa is applied, and δb ₁ corresponds to the magnitude of vibration measured when the excitation force ΔFb is applied.

Therefore,
ΔFa = Fm−Fg (1)
ΔFb = −Fm−Fg (2)
Deri, again
ΔFa = K · δa ₁ (3)
ΔFb = K · δb ₁ (4)
Here, K is a proportional constant representing the excitation force and the magnitude of vibration, and the following equations are established from equations (1), (2), (3), and (4).
| Fm | = | ΔFa−ΔFb | / 2
= K · | δa ₁ -δb ₁ | / 2 (5)

The unbalanced magnetic attractive force Fm resulting from the eccentricity of the air gap 6 increases in accordance with the amount of eccentricity of the air gap 6, and the magnitude of vibration increases accordingly. Therefore, when the magnitude of vibration according to the amount of eccentricity of the air gap 6 in the measurement direction is δy, the magnitude of vibration δy is expressed by the following equation.
δy = | δa ₁ −δb ₁ | / 2 (6)
The direction of eccentricity of the air gap 6 is determined by one of the following two cases.
(A) In the case of δa ₁ <δb _{1 When} the measurement result δb ₁ after the compressor is rotated 180 ° is larger than the measurement result δa ₁ before the rotation, the air is moved vertically downward depending on the position of the compressor after the rotation 180 °. The gap 6 is eccentric.
(B) In the case of δa ₁ > δb _{1 When} the measurement result δb ₁ after the compressor is rotated 180 ° is smaller than the measurement result δa ₁ before the rotation, the air is moved upward in the vertical direction depending on the position of the compressor after the rotation by 180 °. The gap 6 is eccentric.

In the above description, the magnitudes of vibrations δa ₁ and δb ₁ are respectively measured at the reference position (rotation angle 0 degree) and the position where the compressor 1 is rotated 180 degrees in the circumferential direction from the reference position. This is a case where the magnitude of vibration δy according to the amount of eccentricity of 6 is determined. In the first embodiment, the compressor 1 is further rotated by 90 degrees from the reference position, and is further 90 + 180 degrees from the reference position. The magnitudes of vibration δa ₂ and δb ₂ are measured at the rotated positions. If the magnitude of vibration according to the amount of eccentricity of the air gap 6 at this time is δx, the magnitude δx of the vibration is expressed by the following formula, as in the case of formula (6).
δx = | δa ₂ −δb ₂ | / 2 (7)

In this case, as shown in FIG. 7, the magnitudes of vibration δx and δy according to the eccentricity of the air gap 6 obtained by the above equations (6) and (7) are two axes (X axis, Y The magnitude of vibration along the axis. On the other hand, in the electric motor 2 when the AC voltage is applied, the eccentric amount Δ of the air gap 6 and the magnitude of vibration δ measured on the outer periphery of the electric motor 2 are straight lines as shown in FIG. There is a relationship. Therefore, an experiment using a test work is performed in advance, and by examining the linear relationship between the vibration magnitudes δx, δy measured by the acceleration pickup 39 and the eccentric amounts Δx, Δy of the air gap 6, the X axis The amount of eccentricity Δx can be obtained from the magnitude δx of the vibration about δ, and the amount of eccentricity Δy can be obtained from the magnitude δy of the vibration about the Y axis.
That is, the following relationship is established.
Δx = h1 · δx (8)
Δy = h2 · δy (9)
Here, h1 and h2 are proportional constants indicating the relationship between the magnitude of vibration and the air gap eccentricity.

When the eccentric amounts Δx and Δy about the X axis and the Y axis are obtained in this way, the actual eccentric amount Δ and the eccentric direction α of the air gap 6 can be calculated by the following equations.
Δ = √ (Δx ² + Δy ² ) (10)
α = tan ⁻¹ (Δy / Δx) (11)
Thus, the eccentric amount Δ and the eccentric direction α of the air gap 6 can be expressed by two-dimensional coordinates on a plane perpendicular to the main shaft 12 of the rotor 4.

  As described above, according to the first embodiment, the positional relationship between the rotor 4 and the stator 5 is directly visually confirmed by measuring only the vertical vibration magnitude of the compressor 1 by the acceleration pickup 39. Even in a finished state of the product that cannot be performed, the eccentric state (the eccentric amount and the eccentric direction) of the air gap 6 can be accurately obtained.

Embodiment 2. FIG.
In the first embodiment, the entire compressor 1 is rotated along the circumferential direction around the main shaft 12 of the rotor 4 to obtain measured values δa ₁ , δb ₁ , δa ₂ , and δb ₂ at four vibration positions. Thus, the magnitudes δx and δy of vibration along two directions (X axis and Y axis) orthogonal to each other are obtained. In the second embodiment, the position at which the vibration of the compressor 1 is measured is set more finely. Thus, the measurement accuracy of the eccentric amount and the eccentric direction of the air gap 6 is increased.

  That is, in the second embodiment, as in the case of the first embodiment, the compressor 1 of FIGS. 1 and 2 is the measurement object, and the apparatus 30 having the same configuration as that shown in FIGS. 3 and 4 is used. Then, the eccentric amount and the eccentric direction of the air gap 6 of the electric motor 2 are measured.

In this case, the difference from the first embodiment is that in the flowchart shown in FIG. 9, the prescribed number of times k in S9 is set to a multiple of “2” and a value of “8” or more. The measurement position is changed for each θi along the circumferential direction around the main shaft 12 of the rotor 4. At this time, θi is given by the following equation.
θi = i × (360 / k) (i = 1, 2,..., k) (12)

  Then, the processes from S2 to S10 are repeatedly executed, and the process is terminated when the number of measurement n exceeds the specified number k, and the magnitudes of vibrations at different k positions along the circumferential direction of the compressor 1 are determined. Measure sequentially. In this case, as shown in FIG. 10, with the compressor 1 installed on the mounting table 32, two-dimensional coordinates are taken on a plane perpendicular to the main shaft 12 of the rotor 4, and the vertical upward direction is the positive direction of the Y axis. The X axis is taken so as to be a coordinate system. The angle θi is taken counterclockwise from the positive direction of the X axis.

When the measurement result δi of the magnitude of vibration at each angle θi (i = 1, 2,..., K) is thus obtained, a pair of measurement points δaj, δbj (j = 1, 2,. , K / 2), the vibration magnitude δj is calculated by the following equation.
δj = | δaj−δbj | / 2 (j = 1, 2,..., k / 2) (13)
Then, each eccentric amount Δj corresponding to each vibration magnitude δj is obtained from the relationship shown in FIG. Further, the magnitude relationship between the measurement points δaj, δbj (j = 1, 2,..., K / 2) facing each other is examined, and the angle θi when giving the larger measured value is adopted as the eccentric direction γj. To do.

Thus, when k / 2 eccentricity value Δj and eccentric direction value γj are obtained, the sum of vibration magnitude Δx along the X axis and the sum of vibration magnitude Δy along the Y axis are obtained. Is obtained by the following equation.
(Δx, Δy)
= (1 / (k / 4) · Σ _{j = 1, K / 2} Δj · cosγj,
1 / (k / 4) · Σ _{j = 1, k / 2} Δj · sin γj) (14)

  If the sum of the vibration magnitudes Δy and Δx in the X-axis and Y-axis directions is obtained from the equation (14), the actual eccentricity Δ of the air gap 6 can be obtained from the equations (10) and (11). The eccentric direction α can be calculated.

  As described above, according to the second embodiment, in addition to the effects of the first embodiment, by setting the position for measuring the vibration of the compressor 1 more finely than in the first embodiment, The measurement accuracy of the eccentric amount and the eccentric direction of the gap 6 can be further increased.

Embodiment 3 FIG.
FIG. 11 is a front sectional view showing a schematic configuration of an air gap eccentricity measuring apparatus according to Embodiment 3 of the present invention in which an electric motor of a compressor is measured, and FIG. 12 is a side sectional view of the same apparatus. Parts corresponding to those of the configuration of the first embodiment shown in FIG.

  In the first and second embodiments, the operation for changing the position at which the vibration of the compressor 1 is measured is all performed manually. In the third embodiment, the measurement position changing operation is semi-automated to perform the measurement operation. This is a way to save time.

  That is, in the air gap eccentricity measuring apparatus according to the third embodiment, the acceleration pickup cylinder 37 is provided between the pair of left and right mounting tables 32 provided on the upper surface of the base 31 so as to extend and contract along the vertical direction. . An acceleration pickup 39 is attached to the upper end of the acceleration pickup cylinder 37 via a vibration isolating material 38. Therefore, the acceleration pickup 39 moves up and down in the vertical direction as the acceleration pickup cylinder 37 expands and contracts.

  Further, on the outside of the pair of mounting tables 32 on the base 31, the peripheral side portions on the terminal side (right side in FIG. 12) and the foot 19 side (left side in FIG. 12) of the shell 3 of the compressor 1 are respectively provided. A pair of left and right clamp mechanisms 45 for clamping are disposed to face each other. Each clamp mechanism 45 is slidably provided on a column 46 erected from the base 31, and each clamp mechanism 45 includes a mechanism moving cylinder that slides the mechanism 45 up and down along the column 46. 47 and a mechanism rotating motor 48 for rotating the mechanism 45 are provided.

  Each clamp mechanism 45 itself has a well-known structure, and has clamp claws 49 that protrude along the main shaft 12 of the rotor 4 at three locations along the circumferential direction of the shell 3 of the compressor 1. Further, a flat plate 50 is fixed along the vertical direction to one clamp mechanism 45 (the left side in FIG. 12), and this flat plate 50 is used to determine the measurement position of the vibration of the compressor 1 by the acceleration pickup 39. One positioning hole 51 is formed.

The clamp mechanism 45, the mechanism moving cylinder 47, and the mechanism rotating motor 48 correspond to the automatic measurement position changing means in the claims.
Since other configurations are the same as those in the first embodiment, detailed description thereof is omitted here.

  In the air gap eccentricity measuring apparatus 30 according to the third embodiment, when changing the position at which the vibration of the compressor 1 is measured, the compressor 1 is connected to the main shaft of the rotor 4 in advance as shown in FIG. 12 is placed on the anti-vibration material 34 so as to be horizontal, and the phase of the compressor 1 is determined by aligning the positions of the reference hole 20 and the positioning hole 51 of the foot 19 with the positioning pin 42.

  Then, as shown in FIG. 13B, after clamping the peripheral side portion of the shell 3 of the compressor 1 with the clamp claws 49 of the both clamp mechanisms 45, the mechanism moving cylinder 47 is extended to expand the compressor 1. It moves upward along the column 46. Next, as shown in FIG. 13C, the compressor 1 is rotated about the main shaft 12 of the rotor 4 to a predetermined angle by rotating the mechanism rotation motor 48. Subsequently, as shown in FIG. 13 (d), the mechanism moving cylinder 47 is retracted to move the compressor 1 downward, and the compressor 1 is placed on the vibration isolator 34. With this series of operations, the vibration measurement position of the compressor 1 can be changed.

  The measurement procedure of the eccentric state (the eccentric amount and the eccentric direction) of the air gap 6 in the third embodiment is shown in the flowchart of FIG. The measurement procedure in this case is the same as that in the first or second embodiment. That is, the eccentric state of the air gap 6 may be calculated based on four measured values as in the first embodiment, or the air gap may be calculated based on a larger number of measured values as in the second embodiment. 6 may be calculated to increase the measurement accuracy. 14 correspond to the procedure shown in FIGS. 13A to 13D.

  As described above, according to the third embodiment, the clamp mechanism 45 is moved up and down by the mechanism moving cylinder 47 and rotated by the mechanism rotating motor 48, so that the compressor clamped by the clamp mechanism 45 is used. 1 vibration measurement position can be easily changed. For this reason, the measurement of the magnitude of vibration by the acceleration pickup 39 can be performed semi-automatically, and labor and labor at the time of measurement can be saved.

  In the first and second embodiments, the acceleration pickup 39 is positioned above the compressor 1 to measure vibration. However, the acceleration pickup 39 may be attached below the compressor 1 to measure vibration. Good. Also in the third embodiment, the acceleration pickup 39 is positioned below the compressor 1 to measure vibration, but it can also be attached above the compressor 1 to measure vibration.

  In the first to third embodiments, the acceleration pickup 39 is used as a sensor for measuring the vibration of the compressor 1. However, the acceleration pickup 39 is not a type that measures acceleration, but may be one that measures speed or displacement.

  Furthermore, in said Embodiment 1-3, although the measuring object was set to the compressor 1 carrying the single phase induction motor 2, it is a compressor carrying not only a single phase induction motor but a multiphase induction motor. Furthermore, in addition to the compressor, the present invention can be applied when it is necessary to simply measure the eccentric amount and direction of the air gap of various electric motors.

It is a longitudinal cross-sectional view of the compressor carrying the single phase induction motor used as air gap eccentricity measurement object. It is sectional drawing which follows the AA line of FIG. It is front sectional drawing which shows schematic structure of the air gap eccentricity measuring apparatus in Embodiment 1 of this invention. It is side surface sectional drawing of the apparatus. It is a flowchart with which it uses for description of the air gap measuring method in Embodiment 1 of this invention. It is a schematic diagram which shows the relationship between an air gap eccentric state and the magnitude | size of the vibration of an electric motor. It is explanatory drawing in the case of calculating | requiring the eccentric amount and eccentric direction of an air gap from the magnitude | size of the vibration obtained by a two-dimensional coordinate system. It is a characteristic view which shows the relationship between the magnitude | size of vibration, and the amount of air gap eccentricity. It is a flowchart with which it uses for description of the air gap measuring method in Embodiment 2 of this invention. It is explanatory drawing of the two-dimensional coordinate system applied at the time of the air gap eccentricity measurement in Embodiment 2 of this invention. It is front sectional drawing which shows schematic structure of the air gap eccentricity measuring apparatus in Embodiment 3 of this invention which made the measurement object the electric motor of a compressor. It is side surface sectional drawing of the apparatus. It is explanatory drawing with which operation | movement description in the case of changing the position which measures the vibration of a compressor with the same apparatus is provided. It is a flowchart with which it uses for description of the air gap measuring method in Embodiment 3 of this invention.

Explanation of symbols

1 Compressor, 2 Electric motor, 4 Rotor, 5 Stator, 6 Air gap,
12 spindles, 30 air gap eccentricity measuring device, 32 mounting table,
37 acceleration pickup cylinder, 38 anti-vibration material, 39 acceleration pickup,
42 positioning pin, 45 clamping mechanism, 47 mechanism moving cylinder,
48 Mechanism rotation motor.

Claims (7)

An apparatus for measuring the eccentricity of an air gap between a rotor and a stator of an electric motor,
An installation base capable of fixing the whole motor in a plurality of postures rotated about the main shaft in a horizontal orientation of the main shaft of the rotor, and vibration for measuring a vertical vibration amount of the motor when the rotor is rotated And an air gap eccentricity measuring device for an electric motor . The motor air gap eccentricity measuring device according to claim 1, wherein the motor installation surface of the installation table is formed in a V shape. The apparatus for measuring an air gap eccentricity of an electric motor according to claim 1 or 2, wherein a vibration isolating material is provided at a portion of the installation base that comes into contact with the electric motor. The above installation base is a base base,
A mounting table for mounting the electric motor provided on the base;
4. The apparatus according to claim 1, further comprising a flat plate that is erected from the base so as to be orthogonal to the main shaft of the electric motor mounted on the mounting table and has a positioning hole for fixing the electric motor. An air gap eccentricity measuring device for an electric motor as described. Air gap eccentricity measuring apparatus of an electric motor according to any one of claims 1 to 3, characterized in that an automatic measurement position changing means for changing the vibration measurement position by the upper Symbol vibration measuring means. A method for measuring an eccentric state of an air gap between a rotor and a stator of an electric motor, wherein the electric motor is installed and positioned so that a main shaft of the rotor is horizontal, and the rotor is driven to rotate after positioning. The vibration amount measuring step for measuring the vibration amount in the vertical direction of the electric motor in the state, and each position on two virtual axes that are orthogonal to each other about the main axis of the rotor are set as vibration amount measurement positions. A measurement position changing step of sequentially changing the measurement position by rotating the entire motor, and repeating the above steps until the entire motor makes one round around the main shaft of the rotor, thereby obtaining each measurement position. An air gap eccentricity measuring method for an electric motor , wherein an eccentric amount and an eccentric direction of an air gap of the electric motor are obtained based on each vibration amount in a vertical direction. In the measurement position changing step, instead of sequentially changing the measurement position by rotating the entire motor so that each position on two virtual axes orthogonal to each other about the main axis of the rotor is set as the measurement position, The position on each axis when the two virtual axes orthogonal to each other about the main axis of the rotor are rotated along the circumferential direction in increments of smaller than 90 degrees is set as the measurement position of the vibration amount. 7. The method for measuring an air gap eccentricity of an electric motor according to claim 6 , wherein the measurement position is changed by rotating the entire electric motor.

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