Some standard content:
ICS33.120
Machinery Industry Standard of the People's Republic of China
JB/T970-1999
Fan balance accuracyforair conditioning
Fan balance accuracyforair conditioningPublished on 1999-07-12
National Bureau of Machinery Industry
Implemented on 2000-01-01bzxz.net
JB/Y9070-1999
This standard is a revision of 2BJ7204890 "Fan balance accuracy for air conditioning".
This standard replaces ZBJ72048-90 from the date of implementation. This standard is issued and submitted by the National Technical Committee for Standardization of Refrigeration Equipment. The responsible drafting unit of this standard: Yuyao Tanfeng Air Conditioning Equipment Co., Ltd. This standard is originated by Zhang Jingzheng and Mei Shuang, and is the mechanical industry standard of the People's Republic of China. This standard specifies the balance accuracy of fans for air conditioners (hereinafter referred to as fans) and the measurement method. This standard applies to the balance accuracy of fans for air conditioners. Reference standards: JB79070-1959, 172, 1I4X H, and the provisions contained in the above standards. The referenced documents in this standard constitute the standard. When the standard is published, the versions shown are valid. All standards will be revised. All parties to this standard should explore the possibility of using the latest versions of the following standards: G04201-1981 General horizontal balance machine calibration method Fan rotor type
The fan impeller rotor type is shown in Figure 1 to Figure 9. The transmission type shown in Figure 3-6 includes a shaft-through fan, 3.1 Limited to 1 pressure-adopting external rotation two-motor multi-wing flat high-center type! Output: The small wheel is fixed on the external rotation of the motor
External F motor
3.1 Two 2 are two coins installed on the wheel, in a symmetrical position 1 double common wind (or single inlet) called wheels. Transmission station is a wheel installation shop.
Approved by the State Machinery Industry Bureau on July 12, 1999. Figure 2
Implemented on January 1, 2000
B/T9070-1999
3.3 Figure 3 shows that the impeller is directly mounted on the motor shaft head. Impeller
Motor
3.4 Figure 4 shows that the two impellers are respectively installed at the symmetrical positions of the left and right shaft heads of the motor. Impeller
Motor
3.5 Figure 5 shows that the impeller is installed at one end of the transmission group, and the blade-end is equipped with a pulley. JB/T9070—1999
3. Figure 6 shows that the impeller is installed at one end of the transmission group. The other end is connected to the coupling pump, and the return wheel
37 Figure 7 shows that more than two impellers are installed on a common shaft, one end of the shaft is supported by a bearing, and the other end is supported by a motor. The impeller
3.8 Figure 8 shows that more than two impellers are installed on a common shaft, the shaft end is supported by a cat bearing, and the drive pulley is installed on the outer side of a chrysanthemum bearing.
9070-1999
3.99 is a negative flow fan impeller with one end supported by a bearing and the other end supported by a drive motor. Request motor
4 Balancing method
4.1 Static balance
4, 1 [Robbery or rotation of the parts to be balanced: The ratio of the width of the fan wheel to the diameter is less than .1: b) When static balance can meet the essential requirements of balance; Figure 9
When the rotor is only statically balanced (i.e. single-plane balancing) corrected. 4.1.2 During static balancing, the formula for calculating the center of gravity on the correction plane is as shown in formula (1)! fnurs
In the formula: e,
The product of the center of gravity offset on the balancing correction plane is, m or g: mm.kg(r)
The product of the unbalance amount m and the distance from the center of rotation in the plane, mm: The weight of the rotor. k
4.1.3 The expression method of balancing accuracy is shown in formula [2] ee
In the formula:
Balance accuracy, mm/s;
2-- The center of gravity offset on the correction plane, m; The maximum operating speed of the rotor: Tads;
The maximum operating speed of the rotor, n.
4.2 Dynamic balancing
4.2.11 The impeller is dynamically balanced when: a) it can also meet the requirements of 4.1.1; b) there are higher requirements for the vibration and noise during the operation of the unit or there are special provisions for the balancing accuracy of the impeller: (
4.2.2 During dynamic balancing, the calculation formulas for the center offset band on the two straight planes are shown in formula (1) and formula (4), and see Figure 10: (mr)g
(3)
E/90701999
(mur)a
Book collection
When the center of gravity of the rotor is within the range of L/6 from the two bearing span points to the right and left, and the correction plane is equidistant from the center water level . In formula (and formula (4), take L-1/L-1, then the calculation formula of the unbalanced disk m () on the two correction planes is shown in formula (): eaf
4.1.1 Expression of balancing considerations The same as formula (4.1.3), 4.3 Balance requirements for different rotor types
4.3.1 For the rotor type shown in Figure 1, the rotor center is set at the center point of the bearingless distance. The weight of the rotor is the weight of the outer rotor of the motor plus the weight of the impeller. The left and right correction planes are on the left and right sides of the outer rotor motor. From the top, the weight of the impeller on the left and right sides is divided into 12 stages and the calculation is carried out. After the impeller and the outer rotor motor are installed, the overall dynamic balance is carried out. The motor shaft is used as the symmetrical fulcrum, and the balancing parts are set in the dovetail shape at both end surfaces of the motor. 4 .3.2 For the rotor types shown in Figures 2, 5 and 8, when the impeller is balanced separately, the impeller and shaft are dynamically balanced according to the requirements of 4.3.1, and the weight of the impeller is the weight of the impeller plus the weight of the auxiliary weight plate. In order to eliminate the influence of the pulley on the balance accuracy after installation, the balance accuracy requirements can be appropriately increased. When the impeller is dynamically balanced as a whole, the weight distribution of the left and right sides should be calculated according to the formula specified in 4.2.2. The weight of the rotor is the weight of each impeller plus the weight of the shaft and the pulley weight plate. 4.3.3 For the rotor types shown in Figures 3 and 4, regardless of the size of the motor rotor, the impeller is balanced separately, and the weight of the impeller is balanced separately, and the balance accuracy requirements are appropriately increased to compensate for the assembly process. 4.3.4 For the rotor types shown in Figures 6 and 7, a coupling is usually used between the motor and the impeller shaft, so the dynamic balance of the motor is not considered. Only the impeller is dynamically balanced after the common shaft is installed. The weight of the impeller is the weight of each impeller, and the accuracy requirement is appropriately increased to compensate for the impact of the installation error. The balance is carried out in accordance with the provisions of 4.3.2. 5 Balancing accuracy
According to the different rotor types and half-balancing methods of the machine, the balancing accuracy limit of the impeller is 6.3: corresponding to the rotor at the same working speed, the allowable single center shift test e, and the table 1 is checked: the highest working speed of the rotor
allowable center of gravity shift!
or by formula (2) to obtain
B/T 9070—[999
1000×G_60000×G
After the rotor is weighed and the center distance is determined, the allowable unbalance value (value) in the correction plane is calculated using formula [1], formula (3) and formula (4). This value is compared with the residual unbalance value actually read on the instrument of the dynamic balancing machine to determine whether it is appropriate. 6 Inspection of balancing accuracy
6. Requirements for balancing equipment and mounting: a) The weight of the balancing workpiece should be within the load range allowed by the equipment; b) The balancing equipment should be regularly measured according to the provisions of 0B 4201, and its accuracy should be higher than or equal to the balancing accuracy requirements of the following parts: ) The balancing shaft used for the workpiece should have sufficient latitude and the vertical displacement should be minimized, and should be calibrated by dynamic semi-balance, and its balancing accuracy should be 2.5 level:
d) The matching of the balancing shaft and the impeller hole is a transitional matching, and its coaxiality requirement should not be greater than 2mm: The supporting surface of the balancing shaft should be restored, and its hardness should not be less than 40HRC: The surface roughness R should not be higher than 1.6μm: The error of the angularity and cylindricality should not be less than half of IT6.
6.2 Requirements for counterweights:
a) The material of the counterweight of the welded impeller should be the same as that of the base material, and its width should not exceed that of the base material to be welded. It should be fully welded to the impeller using the same welding method as the impeller. The shape of the counterweight should also be beautiful, and the four sides should be inverted; b) When the impeller counterweight is in the form of thin plate folding and biting, the folding should be firm and there should be no looseness; when the counterweight is fixed by hammering, anti-loosening measures should be adopted;
) When the impeller requires very little counterweight, or for rotating parts such as cast wheels, the eccentricity of the parts can also be reduced by grinding or drilling to achieve the balance requirement. However, the grinding and drilling of the parts does not affect the strength of the structure: d) When the balance weight is used on the front side (for example, the electric cutting counterweight is used), the excess block should be removed on the premise of meeting the counterweight requirements, so that the counterweight is reduced to a minimum and fixed firmly; the number of balancing weights on the same calibration plane should not exceed two (except for sliding counterweights), and the relative difference between the two weights should not exceed 90°. The outer edge of the counterweight should be less than 10mm away from the outer edge of the measuring wheel. 6.3 For a rotating component assembled from two or more parts, when the whole is not balanced after assembly, the sum of the remaining unbalance of each part and the sum of the unbalances generated shall be the total allowable unbalance of the assembled component. For this reason, the precision test requirements of this type of components should be appropriately improved to ensure the overall balancing accuracy. Marking of balancing accuracy in drawings
7.1 The balancing method and accuracy requirements shall be specified (see Figure 1 for an example of single-plane balancing method and Figure 12 for an example of double-plane balancing method) 6
Projection correction]
JBrt 90701999
(correction)
7.2 The position of the calibration stop surface shall be indicated [single-plane or double-plane. Gim (ats:ig*mm:
[with calibration surface
7.3 The weight and tolerance of the rotor shall be marked, the maximum operating speed, that is, the allowable residual unbalance mrg, mm).
Tip: This standard content only shows part of the intercepted content of the complete standard. If you need the complete standard, please go to the top to download the complete standard document for free.