JPH11344405A - Correction method for dynamic balance of rotating machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a correction method in which a dynamic balance is obtained with high accuracy by correcting not only the imbalance of a component in the radial direction but also the imbalance of a component in the axial direction. SOLUTION: The dynamic balance of a rotating body is measured, and a dynamic imbalance mass at a prescribed mass is then formed in a position which is deviated by a prescribed angle from a first dynamic imbalance position which is measured (a trial machining operation). After that, the dynamic imbalance of the rotating body is measured again, and the dynamic imbalance is corrected. Thereby, since the dynamic imbalance mass at the prescribed mass is added to the imbalance of a component in the axial direction in addition to a first dynamic imbalance mass, the imbalance becomes large as compared with that before the trial machining operation. Consequently, since the imbalance of the component in the axial direction can be measured with high accuracy after the trial machining operation, a dynamic balance can be obtained with high accuracy.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a wesco pump,
The present invention relates to a method of correcting a dynamic balance of a rotating machine that corrects a dynamic imbalance of a rotating machine such as a centrifugal fan or an electric motor.

[0002]

2. Description of the Related Art A general dynamic balance correcting method for a rotating machine is as follows. That is, by measuring the vibration of the rotating machine by operating (rotating) the rotating machine, the dynamic unbalanced mass and the position of the dynamic unbalanced mass are measured, and then the dynamic unbalanced mass is corrected. , Adding a new weight to the rotating body of a rotating machine,
In addition to performing correction processing such as cutting a part of the rotating element, the above operation is repeated until the result of the vibration measurement becomes less than a predetermined value.

[0003]

In the above method, in order to obtain a dynamic balance (dynamic balance) with high accuracy, the dynamic unbalance mass and the position of the dynamic unbalance mass are determined. It is necessary to measure (accurately) with high accuracy, and to accurately correct the measured dynamic unbalance mass and its position.

[0004] However, if the mass or position to be added or cut is slightly different from the measured dynamic unbalance mass and position when performing the correction processing, a new dynamic unbalance is affected by the correction processing. Will occur. on the other hand,
In order to perform complete correction processing with the measured dynamic unbalanced mass and position, it is naturally necessary to perform correction processing with high processing accuracy, so the difficulty of correction processing increases, and eventually, high precision It is highly possible that dynamic balance cannot be obtained.

In view of the above, an object of the present invention is to obtain a dynamic balance with high accuracy.

[0006]

The present invention uses the following technical means to achieve the above object. Claim 1
In the invention described in Item 3, after measuring the dynamic unbalance of the rotating body (2, 7), a dynamic unbalance mass having a predetermined mass is formed at a position shifted by a predetermined angle from the first dynamic unbalance position. Then, the dynamic imbalance of the rotating body (2, 7) is measured again. Then, the dynamic unbalance is corrected based on the predicted value of the dynamic unbalance mass generated in the first correction step and the predicted value of the position thereof, and the second dynamic unbalance mass and the second dynamic unbalance position. It is characterized by the following.

[0007] Thus, the predicted value of the dynamic unbalance mass and the predicted value of the position (hereinafter, these are referred to as predicted values) generated in the first correction step, and the measured second dynamic unbalance are calculated. When the mass and the second dynamic unbalance position (hereinafter, these are referred to as actual measurement values) are different, the actual measurement value includes, in addition to the dynamic imbalance predicted to occur in the first correction process, It can be considered that a new dynamic imbalance accompanying the first correction step is included.

Therefore, in the second correction step, if the correction processing is performed in consideration of the difference between the actually measured value and the predicted value, a dynamic balance can be obtained with high accuracy. On the other hand, if there is no difference between the measured value and the predicted value, it can be considered that a new dynamic imbalance does not occur along with the first correction processing, so that the second correction is performed similarly to the first correction step. If performed, dynamic balance can be obtained with high accuracy.

According to the invention described in claim 2, the rotating body (2,
7) A weight having a mass equal to the first dynamic unbalance mass is added at a position shifted by 120 ° from the first dynamic unbalance position with the rotation center (O) as a center. As a result, as will be described later, the problem that the imbalance of the radial component cannot be measured with high accuracy (accurately), or the problem that the dynamic imbalance newly generated in the first correction process is large and cannot be corrected cannot be performed. Since occurrence can be prevented beforehand, dynamic balance can be obtained with high accuracy.

According to the third aspect of the present invention, the rotating body (2,
7) Cutting a mass equal to the first dynamic unbalance mass at a position shifted by 60 ° from the first dynamic unbalance position about the rotation center (O). Thereby, the same effect as that of the invention described in claim 2 can be obtained. Incidentally, the reference numerals in parentheses of the above-mentioned respective means indicate examples of the correspondence relation with specific means described in the embodiment described later.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment)
The dynamic balance correction method for a rotary machine according to the present invention is applied to a vortex-type electric air pump (hereinafter, abbreviated as a pump) as the rotary machine.

Before describing a method for correcting the dynamic balance of a rotary machine, the general structure of the pump will be described. In FIG. 1, reference numeral 1 denotes a resin pump housing;
Is a plurality of blade grooves 2a rotating in the pump housing 1.
It is a resin impeller (rotating body) made of Reference numeral 3 denotes an electric motor (drive means) for driving the impeller 2 to rotate.
The impeller 2 is a motor shaft (rotation axis) of the electric motor 3.
3a.

Reference numeral 4 denotes a resin motor cover which is fixed to the pump housing 1 and covers the electric motor 3 and houses a filter 5 for removing dust from the air. It is a resin pump cover that forms the pump chamber 2b by covering the impeller 2 together with the housing 1. The pump cover 6 has a discharge port 6a for discharging air pressurized in the pump chamber 2b, while the motor cover 4 has an air suction port 4a. Reference numeral 7 denotes a metal plate fixed to the motor shaft 3a and rotated integrally with the impeller 2.

Next, a dynamic balance correction method for a rotating machine (hereinafter, abbreviated as balance correction method) will be described.
As a pre-process of the balance correction process, a vibration measuring device 10 including an acceleration sensor for detecting a radial vibration D ₁ of the impeller 2 and a rotational axis vibration D ₂ orthogonal to the radial vibration D ₁ is installed in the pump housing 1. A rotation sensor (rotation speed detection means) 11 for detecting the rotation speed (angular speed) of the impeller 2 is mounted on the pump cover 6.

Incidentally, as shown in FIG. 2, the rotation sensor 11 measures the pulse signal generated when the mark 11a attached to the impeller 2 passes through the portion where the rotation sensor 11 is installed, thereby detecting the rotation of the impeller 2. Detect the number of rotations. Hereinafter, the balance correction method will be described in the order of steps based on the flowchart shown in FIG.

1. Initial Vibration Measurement Step (S100) The dynamic imbalance of the impeller 2 and the plate 7 (hereinafter, collectively referred to as a rotating body R) is measured (calculated) from the values detected by the vibration measuring device 10 and the rotation sensor 11. , A first dynamic unbalance position, and a first dynamic unbalance mass at that position (first correction step).

Incidentally, a vector MR _{0 in} FIG. 2 is a vector indicating an unbalance amount consisting of the first dynamic unbalance position and the first dynamic unbalance mass. Hereinafter, this vector is referred to as an initial unbalance vector MR _0. Call. Further, in this specification, the unbalance amount means a vector amount including the first dynamic unbalance position and the first dynamic unbalance mass.

2. Trial processing step (S110) Around the rotation center O of the rotating body R (see FIG. 2), the first
First movement at a position 120 ° shifted from the dynamic unbalance position
W having a mass equal to the target unbalance mass ₁Add
(First correction step). At this time, a 120 ° shift
Position of the rotating body R in either the forward direction or the reverse direction.
It may be in that direction.

Incidentally, the vector MR ₁ is a vector indicating the amount of imbalance newly generated in the trial adding process, and this vector is hereinafter referred to as a first correction vector MR ₁ . Incidentally, in FIG. 2, the weight W ₁ is being added only to the impeller 2, as needed to both plate 7 and the impeller 2, or plates 7 only may be added the weight W _1.

3. Vibration measurement step (S120) After performing the sample processing, the dynamic unbalance of the rotating body R is measured again, and the second dynamic unbalance position and the second dynamic unbalance mass at the position are obtained (the second dynamic unbalance mass). 2 measurement process). Incidentally, vector MR ₂ in FIG. 2 is a vector indicating the unbalance amount of a second dynamic unbalance position and the first dynamic unbalance mass, hereinafter called the vector and the second correction vector MR _2.

4. Correction process (S130) Prediction of dynamic unbalance mass generated by sample processing
Values and their predicted values (hereinafter referred to as predicted values).
Huh. ) And the actually measured second dynamic unbalance mass and the second
Dynamic unbalance position (vector MR₀) And based on
In the second dynamic imbalance position to correct the imbalance
A given mass (ideally W₁) Weight W _TwoAppend
(Second correction step).

In FIG. 2, the weight W ₂ is added only to the impeller 2. However, similarly to the trial adding process, the weight W ₂ is added to both the plate 7 and the impeller 2 or only to the plate 7 as necessary. the weight W ₂ may be added. 5. Final vibration measurement step (S140) The dynamic imbalance of the rotating body R is measured, and if the measured value is less than a predetermined value, the balance correction is completed. On the other hand, if the measured value is equal to or larger than the predetermined value, the process returns to the correcting step (S130).

Next, the balance correcting method according to the present embodiment.
The features of Predicted value and measured second dynamic imbalance
Mass and the second dynamic unbalance position (hereinafter referred to as
Called the actual measurement. ) Is different from the actual measurement (vector
Le MR ' ₁) Is predicted to be generated by the trial processing
Dynamic unbalance amount (first correction vector MR₁)
In addition, a new dynamic imbalance due to the trial processing process
(Vector MR "₁) May be considered to be included
(See FIG. 4).

Therefore, in the correction process, if the correction processing is performed in consideration of the difference between the actually measured value and the predicted value, a dynamic balance can be obtained with high accuracy. On the other hand, if there is no difference between the measured value and the predicted value, it can be considered that a new dynamic imbalance does not occur with the trial processing step, so that the correction step is performed similarly to the first correction step. For example, dynamic balance can be obtained with high accuracy.

[0025] Incidentally, in this embodiment, equal the size of the first correction vector MR ₁ is the size of the initial imbalance vector MR _0, and the angle between the first correction vector MR ₁ and the initial imbalance vector MR ₀ Is 120 °, the dynamic unbalance amount newly generated by the trial processing (vector MR ₃ = vector MR ₁ + vector MR ₀ )
The size of, as shown in FIG. 4, equal to the size of the initial imbalance vector MR _0.

By the way, the trial processing is random (random).
In the case where it is applied to, for example, the position after trial processing is the first
Very close to a position 180 ° off the dynamic unbalance position
And when it is different from the first dynamic unbalance position,
Initial unbalance vector MR ₀And the first correction vector MR
₁Combined vector MR with_ThreeBecomes extremely small,
Measures unbalance of radial components with high accuracy (accurately)
(See (a) of FIG. 5).
See). Hereinafter, this problem is referred to as an unmeasurable problem.

In FIG. 5, the + sign of + W ₁ and + W ₂ means that a weight is added, and (+ W ₁ ) indicates the first dynamically unbalanced mass. On the other hand, when the dynamic unbalance mass when the sample processing is performed at random is larger than the first dynamic unbalance mass, the dynamic unbalance amount newly generated by the sample processing becomes large, and the correction is performed. May not be possible (see FIG. 5B).

On the other hand, in the present embodiment, the weight W ₁ having a mass equal to the first dynamic unbalance mass is shifted from the first dynamic unbalance position by a predetermined angle (in this embodiment, 120 °).
°) Since it is added at a shifted position, the above problem does not occur, and dynamic balance can be obtained with high accuracy. (Second Embodiment) In the above embodiment, the weights W ₁ and W ₂ are added to the rotating body R in the trial processing step and the correction processing step. However, in the present embodiment, the weights are equal to the weights W ₁ and W _2. Trial processing and correction processing are performed by cutting (deleting) the mass from the rotating body R.

In this embodiment, since the trial addition processing and the correction processing are performed by cutting the rotating body R, the trial adding processing is performed at the first dynamic unbalanced position about the rotation center O of the rotating body R. It is necessary to cut a mass equal to the first dynamic unbalanced mass at a position shifted by 60 ° from (see FIGS. 6 and 7).
reference). In FIG. 7, -W _1, the -W ₂ - and symbols,
This means cutting a mass equal to the masses W ₁ and W _2, and (+ W ₁ ) indicates the first dynamic unbalanced mass.

In this connection, as in the present embodiment, when the trial adding process is performed by cutting a part of the rotating body R, the trial adding process is performed near the first dynamic unbalance position. In addition, the above-mentioned measurement impossible problem occurs. by the way,
In the above embodiment, when a weight is added to the rotating body R, the initial unbalance vector MR ₀ and the first correction vector M
Angle formed with R ₁ (hereinafter, this angle is referred to as an additional angle)
Is set to 120 °, and when cutting the rotating body R, the angle formed by the initial unbalance vector MR ₀ and the first correction vector MR ₁ (hereinafter, this angle is referred to as a cutting angle) is set to 60 °. This is because the number of times of the trial processing is one. When the trial processing is performed plural times, other angles may be used.

Incidentally, if the trial processing is performed n times, the additional angle is desirably 360 / (n + 2), and the cutting angle is desirably 180 / (n + 2). Also,
In the trial processing, the mass of the weight added to the rotation or the mass to be cut is limited to the first dynamic unbalanced mass measured in the initial vibration measurement process as long as it can be finally corrected in the correction process. Not something.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of an electric air pump to which a dynamic balance correcting method for a rotary machine according to a first embodiment is applied.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a flowchart showing a work process of balance correction.

FIG. 4 is a vector diagram.

FIG. 5 is a vector diagram.

FIG. 6 is a cross-sectional view of the electric air pump to which the dynamic balance correcting method for the rotary machine according to the first embodiment is applied.

FIG. 7 is a vector diagram.

[Explanation of symbols]

2 impeller, 3 electric motor, 4 motor cover, 5
... filter, 6 ... pump cover.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI H02K 15/16 H02K 15/16 A (72) Inventor Mitsuo Inagaki 14 Iwatani, Shimowasumi-cho, Nishio-shi, Aichi Japan Automotive Parts Co., Ltd. In the laboratory

Claims (3)

[Claims] 1. A method for correcting a dynamic imbalance of a rotating machine having a rotating body (2, 7) rotating with a rotating shaft (3a), comprising: The dynamic imbalance of 7) is measured and the first
A first measurement step for obtaining a dynamic unbalance position and a first dynamic unbalance mass at that position; and a rotation center (O) of the rotating body (2, 7) as a center.
A first correcting step of forming a dynamic unbalance mass having a predetermined mass at a position shifted by a predetermined angle from the first dynamic unbalance position; and after the first correcting step, the rotating body (2, 7). A second measurement step of measuring the dynamic unbalance of the second, and obtaining a second dynamic unbalance position and a second dynamic unbalance mass at that position; and a dynamic unbalance mass generated by the first correction step. A second correcting step of correcting a dynamic imbalance based on the predicted value and the predicted value of the position, and the second dynamic unbalance mass and the second dynamic unbalance position. A method for correcting the dynamic balance of a machine. 2. In the first correcting step, the first dynamic position is shifted from the first dynamic unbalance position by 120 ° about a rotation center (O) of the rotating body (2, 7). The method according to claim 1, wherein a weight having a mass equal to the unbalanced mass is added. 3. In the first correcting step, the first dynamic position is shifted from the first dynamic unbalance position by 60 ° about a rotation center (O) of the rotating body (2, 7). The method according to claim 1, wherein a mass equal to the unbalanced mass is cut.