JB/T 7240-1994 Technical requirements for main components of general reciprocating piston compressors JB/T7240-1994 Standard download decompression password: www.bzxz.net

Mechanical Industry Standard of the People's Republic of China
JB/T 7240-1994
General Reciprocating Piston Air Compressor
Technical Conditions for Main Components
Published on 1994-07-18
Ministry of Machinery Industry of the People's Republic of China
Implementation on 1995-07-01
Mechanical Industry Standard of the People's Republic of China
General Reciprocating Piston Air Compressor
Technical Conditions for Main Components
Subject Content and Scope of Application
JB/T7240-1994
This standard specifies the technical requirements, test methods, inspection rules, marking, packaging and storage requirements for the main components of general reciprocating piston air compressors (hereinafter referred to as air compressors). This standard applies to the main components of air compressors with a drive power of 0.18~560kW and a rated exhaust pressure not exceeding 1.4MPa. Cited standards
GB 699
GB1031
GB 1173
GB1184
GB1220
GB1801
GB3077
GB3191
GB9438
GB9439
JB2230
JB2231
JB5439
JB5440
JB5441
JB5442
JB/T6431
JB/T6908
ZB J72 016
ZB J72 025
：Terms
High-quality carbon structural steel
Technical conditions
Surface roughness parameters and their values
Technical conditions for cast aluminum alloys
Shape and position tolerances
Provisions for unmarked tolerances
Stainless steel bars
Tolerance zones and fits of holes and shafts up to 500 mm in size
Technical conditions for alloy structural steels
Aluminum and aluminum alloy extruded bars
Technical conditions for aluminum alloy castings
Grey cast iron parts
Reciprocating piston compressors
Reciprocating compressor
Shaft pin outer diameter size
Cylinder diameter size
Ultrasonic flaw detection of ductile iron parts of compressorUltrasonic flaw detection of forged steel parts of compressor
Ultrasonic flaw detection of cast steel parts of compressor
Magnetic particle flaw detection of important parts of compressor
Technical conditions for gray cast iron parts for positive displacement compressorsTechnical conditions for forged parts of positive displacement compressors
Ductile iron parts for positive displacement compressors
Technical conditions
Reciprocating compressors
The terms of air compressor parts and components shall comply with the relevant provisions of ZBJ72025. 4
Technical requirements
Main parts and components of air compressors shall comply with the provisions of this standard and be manufactured according to drawings and technical documents approved by the prescribed procedures. 4.2 The materials of the main parts of air compressors can be selected according to the provisions of Table 1, and materials with performance not lower than the grades specified in Table 1 can also be used. Approved by the Ministry of Machinery Industry on July 18, 1994
Implemented on July 1, 1995
Part Name
Crankcase
Connecting Rod Body
Crosshead Body
Cylinder Sleeve
Piston Rod
Crosshead Pin
Piston Pin
Connecting Rod Bolt
Connecting Rod Nut
Piston Rod Nut
JB/T7240-1994
HT150，F
HT200, HT250, HT300
ZL108，ZL109
QT700-2
QT600-3，9
40, 45 | | tt | HT300 | | tt | 08, ZL109 | | tt | 45
38CrMoAl,20Cr
30CrMo, 3
35CrMo, 4
30CrMo, 20Cr, 30Mn2
JB/T6431
GB 1173
ZB J72 016| ||GB 699
ZB J72 016
GB 3077
GB3191
JB/T6431
ZB J72 016
JB/T6431
ZB J72 016
GB 1173
JB/T6431
GB 1173
GB3191
GB 699
GB3077,
GB 1220
GB 699
GB3077
GB 699
GB3077
GB 699
GB 3077
Gray cast iron parts of air compressors shall comply with the provisions of JB/T64311. Castings such as fuselage,
crankcase,
middle body, cylinder,
head body, etc. shall be subjected to aging treatment. The radius of the casting fillet not specified shall be 1/6-1/4 of the wall thickness. Pistons, cross
cylinder sleeves,
forgings are not allowed to have white spots and cracks. Air compressor steel forging parts should comply with the provisions of JB/T6908. 4.4
The ductile iron casting parts of air compressors shall comply with the provisions of ZBJ72016. The main parts of ductile iron castings after finishing shall not have defects such as visible sand holes and inclusions. The reinforcement ribs of castings such as cylinder blocks, cylinder seats, cylinder heads and crosshead bodies shall not have cracks, shrinkage holes, shrinkage porosity, etc. The supply status, mechanical properties and other requirements of aluminum alloy casting parts of air compressors shall comply with the provisions of GB9438. The supply status, mechanical properties and other requirements of aluminum alloy forging parts of air compressors shall comply with the provisions of GB3191. The main journals of the crankshaft of the air compressor, the outer diameters of the crank pin, crosshead pin, piston pin and piston rod shall comply with the provisions of JB2230. The cylinder diameter size of the air compressor shall comply with the provisions of JB2231. The thread accuracy of connecting rod bolts and nuts, external threads of piston rods and crossheads of air compressors, and the thread accuracy of internal threads shall not be less than 6g.
JB/T 7240-1994
The tolerance level of important parts of the main parts of air compressors shall not be less than the requirements of Table 2. Table 2
Parts Name
Crankcase
Connecting rod body
Crosshead body
Cylinder (cylinder liner)
Piston rod
Crosshead pin, piston pin
Large bearing hole
Small bearing hole
Part name
Bearing seat mounting hole
Slideway hole
Main shaft journal
Crank Pin
Large and small head holes
Friction surface
Location stoppers at both ends
Slideway hole
Inner cylindrical friction surface
Outer cylindrical friction surface
Friction surface
Friction surface
Equipped with rolling bearing
Equipped with sliding bearing
The surface roughness of the machined surface of the main parts of the air compressor shall not be greater than the values ​​specified in Table 3. Table 3
Parts name
Crankcase
Connecting rod body
Crosshead body
Machinery surface
Main bearing hole
Friction surface of crosshead slideway
Main journal and crankpin
Rounded corners and oil hole rounded corners
Big and small head holes and bolt holes for installing pulley (or coupling)
Friction surface
Pin hole surface
Location stop at both ends
Friction surface of crosshead slideway
Tolerance grade
(GB1801)
H8 (h7)
Surface roughness R
(GB1031)
Part name
Cylinder (including cylinder liner)
Cylinder liner
Piston rod
Cross pin
Live pin
Connecting rod bolt
Connecting rod nut
Piston rod nut
JB/T7240-1994
Continued Table 3
Processing surface
Inner cylindrical friction surface (oil-free machine)
Diameter ≤500mm
>500mm
Inner cylindrical friction surface (oil-free machine)
>300~500mm
>500mm
Outer circle and positioning support end face
Outer circle and both sides of piston ring groove
Mating surface and fitting end face with piston rod
Friction surface
Fitting end face with piston
Thread surface
Transition arc surface
Friction surface
Rounded corner and transition of oil hole rounded corner
Outer surface of positioning part and transition arc surface
Threaded surface
Threaded surface
The shape and position tolerances of main parts of air compressor shall not be lower than those specified in Table 4. Table 4
Part name
Crankcase
Part and tolerance name
Coaxiality of each bearing hole to its common axisSurface roughness R
(GB1031)
Tolerance grade
(GB 1184)
Parallelism of the fitting surface of the mounting cylinder (or middle body) to the common axis of the bearing holeVerticality of the fitting surface of the crosshead clearance axis to the mounting cylinder (or middle body)Coaxiality of the crosshead slideway axis to the axis of the positioning stop of the mounting cylinder (or middle body)
Cylindricity of the crosshead slideway
Part name
Connecting rod body
Crosshead body
Cylinder body
Gas-oxygen sleeve
JB/T 7240-1994
Continued Table 4
Name of parts and tolerances
Cylindricity of main journal and crankpin
Parallelism of crankpin axis to common axis of main journal in vertical and horizontal directions
Radial runout of journal for installing pulley or coupling to common axis of main journal at both ends
Cylindricity of large head hole and small head hole
Parallelism of axis of large and small head hole
Horizontal parallelism of axis of two bolt holes
Verticality of end face of bolt hole to its axis
Coaxiality of axis of friction surface of crosshead to axis of cylindrical surface (or conical surface or thread) matching with piston rod
Verticality of bearing surface of fastening nut for installing piston rod to cylindrical surface (or conical surface or thread) matching with piston rod
Axis of crosshead pin hole Perpendicularity of the line to the axis of the crosshead friction surfaceCylindricity of the friction surface
Coaxiality of the two ends of the positioning stop to the common axisThe perpendicularity of the positioning stop axis to the mating surface of the surfaceThe coaxiality of the crosshead slideway axis to the positioning stop axisThe perpendicularity of the crosshead slideway axis to the mating surface axisCylindricity of the crosshead slideway
Cylindricity of the inner cylindrical surface
Perpendicularity of the inner cylindrical surface axis to the mating surface with the fuselage (or middle body)The coaxiality of the inner cylindrical surface axis to the positioning stop axisThe perpendicularity of the cylinder sleeve positioning flange end face to the working surface axisThe coaxiality of the outer circle axis matching with the cylinder to the cylinder working surface axisCylindricity of the inner cylindrical surface
Perpendicularity of the mating end face matching with the piston rod to the piston locating hole axisThe coaxiality of the outer cylindrical surface axis to the piston locating hole axisThe perpendicularity of the outer cylindrical surface axis to the piston pin hole axisTolerance grade
(GB 1184)
Parts name
Piston rod
Crosshead pin
Piston pin
Connecting rod bolt
Connecting rod nutPiston rod nut
JB/T7240-1994
Continued table 4
Name of parts and tolerances
Coaxiality of the axis of the cylindrical surface (or conical surface) matching with the piston to the axis of the friction surface of the piston rod
Cylindricity of friction surface
Axis of the cylindrical surface (or conical surface or thread) matching with the crosshead Coaxiality of the piston rod friction cylindrical surface axisbzxz.net
Perpendicularity of the piston shoulder end face to the piston rod friction cylindrical surface axisCylindricity of the friction surface
Perpendicularity of the bolt support surface to the bolt axisVerticality of the nut support surface to the thread axisTolerance grade
(GB1184)
4.14The weight of the piston, piston rod, crosshead and connecting rod of the air compressor shall comply with the requirements of the drawings, and the weight deviation shall not exceed 3% of the specified weight. The total weight deviation of the above moving parts shall not exceed 3% of the specified total weight. 4. 15
During the assembly process of the main parts and components of the air compressor, the following items shall be measured, and the measured results shall comply with the requirements of the product drawings and technical documents.
Radial clearance between piston and cylinder;
Internal and external dead point clearance of each level of piston;
Radial clearance and contact between crosshead and crosshead slideway: Radial clearance and contact between crankshaft crankpin and connecting rod big end bearing: Radial clearance and contact between crosshead pin and connecting rod small end bearing; Axial play clearance of crankshaft;
Torque value range and locking reliability requirements between connecting rod bolts and nuts: Tightening and locking requirements of front and rear nuts of piston rod during general assembly: Coaxiality requirements of air compressor and driver during general assembly. Test methods and inspection rules
The air compressor body or crankcase oil pool should be tested for leakage. Inject kerosene into the oil pool and keep it for 4 hours without leakage. 2 The air cavity of the air compressor cylinder, cylinder liner, piston and other pressure-bearing parts shall be subjected to a water pressure test at a pressure not less than 1.5 times the maximum allowable working pressure. 5.2
The pressure holding time shall be not less than 30 minutes, and no leakage shall be allowed. 5.3 The water cavity of the air compressor cylinder and other parts shall be subjected to a water pressure test at a pressure of 0.6MPa, and the pressure holding time shall be not less than 30 minutes, and no leakage shall be allowed. 5.4 The mechanical properties, metallographic inspection methods and chemical analysis methods of gray cast iron parts shall be inspected in accordance with the provisions of GB9439, and in accordance with the provisions of JB/T6431, product drawings and technical documents. 5 The chemical analysis, mechanical properties and heat treatment requirements of the main parts of the air compressor shall comply with the provisions of ZBJ72016, JB/T6431 and JB/T69085.5
, and the test methods shall also be carried out in accordance with the relevant provisions of the above standards. 5.6 The ultrasonic flaw detection and magnetic particle flaw detection tests of the main parts of the air compressor shall be carried out in accordance with the methods specified in JB5439, JB5440, JB5441 and JB5442 respectively, and the results shall comply with the requirements of ZBJ72016, JB/T6431, JB/T6908 and product drawings. 6
Marking, packaging, storage
JB/T7240-1994
When the parts and components shipped with the main machine of the air compressor need to be packed separately, the parts and components of each box shall be indicated on the packing list according to the box number. The product model, name and box number shall be marked in a conspicuous position outside the packing box. 6.2 When the main parts and components of the air compressor are shipped as spare parts, in addition to complying with the provisions of Article 6.1, they shall also have the manufacturer's name and the part's qualification certificate or qualified mark.
6.3 When the main parts and components of the air compressor are packed with the main machine and shipped, the machine shall be wiped clean and the oil seal shall be rust-proofed before packing after the product factory inspection is completed.
6.4 From the date of shipment, the manufacturer shall ensure that the parts and components will not be rusted or damaged due to poor packaging within one year under normal storage and transportation conditions. Special requirements shall be implemented according to the agreement between the supply and demand parties. Additional notes:
This standard is proposed by the National Technical Committee for Compressor Standardization. This standard is under the jurisdiction of the Hefei General Machinery Research Institute of the Ministry of Machinery Industry. This standard is drafted by Nanjing Compressor Factory. The main drafters of this standard are Ming Jun, Wu Hui, Lu Huixian, Yu Guanghe, and Yao Chunzan. 7
People's Republic of China
Mechanical Industry Standard
General Reciprocating Piston Air Compressor
Technical Conditions for Main Components
JB/T 72401994
Published and issued by the China Academy of Mechanical Science
Printed by the China Academy of Mechanical Science
(No. 2, Shouti South Road, Beijing
Postal Code 100044)
Sheet 3/4 Number of words 14,000
Format 880X1230
First printing in January 1995
Number of prints 1-500
Price 6.00 Yuan
Mechanical Industry Standard Service Network: http://www.JB.ac.cn61
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