JB/T 7084-1993 Guidelines for the stacking process of cores for electric tools JB/T7084-1993 Standard download decompression password: www.bzxz.net

Mechanical Industry Standard of the People's Republic of China
Technical Guidelines for the Stacking of Cores for Electric Tools
Subject Content and Scope of Application
B/T7084—1993bzxz.net
This standard applies to the stacking of stator cores fastened by rivets or welding and rotor cores fixed by interference fit or plastic injection molding in electric tools.
2 Reference standards
GB2900.25
GB1958
GB2900.28
GB1184
JB1292
GB9166
JB3915
JB4129
JB/Z331
GB2828
3 Terminology
Electrical terminology Motor
Shape and position tolerance inspection Measurement regulations
Electrical termsElectrical tools
Shape and position tolerancesRegulations without tolerancesSingle-column hydraulic press accuracy
Four-column hydraulic press accuracy
Hydraulic press safety technical requirements
Stamping parts burr height
Electrical tools double insulation guide
Batch inspection counting sampling procedures and sampling tables (applicable to continuous batch inspection)The terms and terms of this standard conform to GB2900.25 and GB2900.28. The following terms are only applicable to this standard. 3.1 Rotor core
Laminated core on the motor rotor.
3.2 Stator core
Laminated core on the motor stator.
3.3 Slotted positioning rod
A rod-shaped component inserted into the slot of the punching sheet to position the stacked sheets when the punching sheets are stacked. 3.4 Slotted test rod
A rod-shaped component that is inserted into the core slot to check the quality of the laminated core. 3.5 Rotor without outer diameter processing
A rotor whose outer diameter is no longer processed after the rotor core is stacked until the assembly is completed. 3.6 Degree of elasticity
After the punching sheets are stacked, the laminated core is deformed in the axial direction due to local stress, which is expressed as L. Ld=LL, '
Where: L. The longest length of the core at the tooth, mm; L—The length of the core near the fastening point, mm. 4 Equipment
The press used should comply with the provisions of JB1292 and GB9166. 4.1
Approved by the Ministry of Machinery Industry on October 8, 1993
Implemented on January 1, 1994
JB/T7084-1993
4.2 Self-made oil (air compressor or other special equipment can be used, but these equipment must meet the corresponding standards. 4.3 The above-mentioned presses used must meet the requirements of JB3915. 5 Clamps
5.1 The clamps should have sufficient rigidity.
5.2 The clamps should not cause danger to the operator. 5.3 The clamps should be designed with reliable positioning structures to ensure the quality of core stacking. 5.4 When using an internal expansion type stator core stacking clamp, the taper of the inner cone sleeve is generally selected from 3° to 5°5.5 When using a gap type stacking clamp, the size of the matching gap should be able to ensure positioning Precision and easy demolding. 5.5.1 The fitting clearance between the locating shaft of the stator core stacking fixture and the inner hole of the stator core can be selected as 0.04~0.06mm. The fitting clearance between the slotted positioning rod of the rotor core stacking fixture and the slot of the rotor punching sheet can be selected as 0.03~0.05mm. 5.5.2 Turning
5.5.3 The fitting clearance between the outer circle of the rotor without outer diameter machining and the fixture positioning hole can be selected as 0.03~0.05mm. 5.6 The verticality or parallelism tolerance of each locating surface of the fixture shall be equal to or higher than the 6th grade accuracy in GB1184. 5.7
The maximum allowable value of the surface roughness parameter Ra of each locating surface is 0.8um. ​​Hardness HRC55~66. When the shape and position of the punching sheet after stacking are out of tolerance, the fixture needs to be corrected or remade. 6 Material Standard Preparation
6.1 The parts used for stacked cores shall comply with the requirements of the drawings. 6.2 The surface of the punching sheets shall be clean and flat.
6.3 The burrs on the punching sheets shall comply with the provisions of JB4129. 7 Test pressure assembly of cores
Before the new product is put into production, it shall be tested according to the process requirements of Chapter 8, and it can only be used in mass production after it has passed the inspection items in Chapter 9.
8 Core stacking process
8.1 Align the marking grooves and align the punching sheets.
8.2 According to the core weight specified in the drawing, weigh a certain amount of punching sheets. If the core weight is not specified in the drawing, calculate and count the corresponding punching sheets according to formula (2) and weigh their weight. P=LxK
Where: P——Number of punching sheets
L—Core stack length, mm ;
K—overlap coefficient;
-nominal thickness of silicon steel sheet, mm.
During press fitting, weight is the main factor, and pressure is allowed to vary within a certain range; the number of sheets should be appropriately increased or decreased to ensure the core length. The core length cannot be controlled by the number of punching sheets. For punching sheets punched out by precision progressive dies, they can also be measured by length, but the influence of the overlap coefficient should be taken into account at this time. 8.3 Place the weighed punching sheets in the fixture in sequence, and place other parts on the core at the same time. 8.4· Pressurize and tighten to make the core reach the specified length. (2)
8.4.1 For the rotor core with secondary forming of shaft insulation, shaft insulation and Class 1 tools, the pressure can be 45MPa. The pressure is related to the net area and interference of the punching sheets. Excessive pressure can easily damage the insulation between the punching sheets, resulting in changes in motor performance. 8.4.2 For riveted stator cores, the pressure can be 78MPa, and then the rivets are tightened. 45
JB/T7084—1993
8.4.3 For welded stator core, pre-press with 4IMPa pressure first, then weld. The welding parameters are selected according to the requirements of the equipment used.
The stacking process of shaft insulation one-time forming rotor core shall be carried out in accordance with the relevant provisions of JB/Z331. 9 Quality inspection
9.1 Core appearance inspection
The core, slot wall and slot, the inner and outer circles of the stator core and the outer circle of the unprocessed rotor shall be smooth and neat, and there shall be no missing corners or unevenness.
Check whether it meets the requirements through observation and manual test. 9.2 Core weight
The core weight shall not be less than the minimum weight specified in the drawing, and its error shall not exceed the weight of a punching sheet. It shall be weighed with a balance during inspection. 9.3 Dimensional accuracy
The length of the core after stacking, the outer diameter of the stator core, and the outer diameter of the rotor without machining the outer diameter shall comply with the requirements of the drawing. 9.4 Shape and position accuracy
9.4.1 The elastic opening of the stator core is near the fastening point and the tooth farthest from the fastening point. The difference between the two shall comply with the requirements of the drawing. 9.4.2 The elastic opening of the rotor core is near the shaft hole and the outer circular tooth part. The difference between the two in the axial direction is measured with a vernier caliper or an outside diameter micrometer, which shall comply with the requirements of the drawing.
9.4.3 The slot error is checked with a slot inspection rod, and all slots should pass. The size of the slot inspection rod is generally 0.10~0.15mm smaller than the slot shape of the punching sheet. 9.4.4 The coaxiality or circular runout shall be checked with a deflection meter or similar instrument and shall comply with the requirements of the drawing. 9.4.5 The slot of the rotor core shall be straight, and the degree of skewness of the slot shall not affect the operation of the next winding process and damage the wire paint mold. 9.5 The influence of the insulating end plate shall be removed during measurement. 9.6 Fastening quality
9.6.1 The rivets of the riveted stator core shall be all flanged and free of cracks. 9.6.2 The weld of the welded stator core shall be flat and smooth, without cold welding or false welding. 9.6.3 If necessary, 7 to 10 times the rated torque of the motor may be applied to the rotor core, and a torsion test may be performed using a torque tester or other torque test methods. The core shall not be loose.
9.7 During inspection, the normal inspection shall be carried out according to the sampling plan when AQL=6.5JL=1 in GB2828. Additional notes:
This standard is proposed and managed by the National Technical Committee for Standardization of Electric Tools. This standard was drafted by the Shanghai Electric Tool Research Institute of the Ministry of Machinery Industry. The main drafters of this standard are Hua Ziqiang and Zheng Keyao.
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