JB/T 5936-1991 General technical requirements for machined parts of construction machinery
Some standard content:
Machinery Industry Standard of the People's Republic of China
JB/T5936—91
Engineering Machinery
General Technical Conditions for Machined Parts
Published on December 12, 1991
Published by the Ministry of Machinery and Electronics Industry of the People's Republic of China
Implemented on July 1, 1992
Mechanical Industry Standard of the People's Republic of China
Engineering Machinery
General Technical Conditions for Machined Parts
Subject Content and Scope of Application
This standard specifies the general technical requirements for machined parts of engineering machinery. This standard applies to all types of machined parts. Cited standards
GB1184
GB1568
JB/T5937
JB/T5938
JB/T5939
JB/T5940
JB/T5941
JB/T5942
GB2828
General requirements
Form and position tolerances Provisions for tolerances not specified Ordinary thread tolerances and fits (diameter 1~355 mm) tolerances
Trapezoidal thread
Technical conditions for thread finish, shoulder distance, undercut groove, chamfer key
Chinese Center hole
Construction machinery
Construction machinery
Construction machinery
Construction machinery
Construction machinery
General technical conditions for gray iron castings
General technical conditions for ductile iron castings
General technical conditions for steel castings
General technical conditions for high manganese steel castings
General technical conditions for nonferrous alloy castings
General technical conditions for free forgings
Batch inspection counting sampling procedures and sampling tables (applicable to continuous batch inspection) All machined parts must comply with the product drawings, process regulations and the requirements of this standard. The surface of the machined parts is not allowed to have defects such as rust, bumps, scratches, cracks, etc. 3.2
Unless there are special requirements, sharp edges, corners and burrs are not allowed on the machined parts. 3.3
3.4 The surface of the finished rolling shall not be peeled or peeled after rolling. 3.5 The finished surface, friction surface, positioning surface and other working surfaces are not allowed to be printed with marks. The processed parts must be protected from damage, corrosion and deformation during transportation and storage. 3.6
Chamfers not specified in the drawings shall comply with the provisions of Figure 1 and Table 1. Table 1
Approved by the Ministry of Machinery and Electronics Industry on December 12, 1991>10~30
>30~100
>100~250
JB/T5936-91
>250~500
>500~1000
Implemented on July 1, 1992
3.8 Chamfering
JB/T5936-91
When the chamfering size is not specified in the drawing and there is no requirement for root cleaning, it shall comply with the provisions of Figure 2 and Table 2. Figure 2
>10~30
Note: ①D value is used for chamfering of blind holes and external end faces. ②Refer to this table for chamfering of non-cylindrical surfaces. >12~30
>36～60
>30~80
>60~260
>80~140
>260~630
>140~200
>630~1000
Parts processed in groups, such as upper and lower bearing shells of sliding bearings, upper and lower covers of gear boxes, etc., should be marked. 4
Unmarked dimensional tolerance
The limit deviation of unmarked dimensional tolerance (excluding fillet radius and chamfer) shall be in accordance with the provisions of Table 3, and its values are shown in Table 4. Table 3.
Hole diameter and inner dimensions
Outer dimensions of shaft diameter
1/2JS(js)14
Basic dimensions
(js14)
Basic dimensions
(js14)
Basic dimensions
(js14)
>80~120
>120~180
JB/T5936-91
>180~250
>10~18
>250~315
The limit deviations of chamfer and rounding radii shall comply with the provisions of Figure 3 and Table 5. Figure 3
c (e,) r (r,)
Limit deviation
Ae (r)
Ac,(Ar,)
>18~30
>315~400
～2000
>30~50
>400~500
>10~30
>50~80
>500~630
～3150
>30~50
The tooth chamfer of gears, turbines and sprockets shall comply with the provisions of Table 6. The limit deviation of the chamfer size shall comply with the provisions of Article 4.2. 3
>10~20
0.5×45°
1×45°
2×45°
JB/T5936—91
Sprocket pitch
The limit deviation of blind hole drilling depth shall not exceed the following provisions: 4.4
When the hole depth is less than or equal to 50mm, the limit deviation is +\mm. When the hole depth is greater than 50mm, the limit deviation is +\mm. b.
4.5When the lowest point is measured at the armor flat, the limit deviation of the Deping depth is +°mm. Chain
4.6The limit deviation of the unmarked dimensional tolerance with one side as the machined surface and the other side as the non-machined surface shall comply with the following provisions. Reverse
0.5×45°
1×45°
2×45°
4.6.1 For castings, forgings and welded parts, the limit deviation of the non-processed unmarked dimensional tolerance specified in the corresponding general technical conditions for engineering machinery shall be taken as the ± 70% value.
4.6-2 The flange or wall thickness of castings and forgings is allowed to be thinned. When the wall thickness is less than or equal to 10mm, the thinning amount shall not exceed 20% of the wall thickness; when the wall thickness is greater than 10mm, the thinning amount shall not exceed 15% of the wall thickness. 5 Unmarked shape and position tolerance
5.1 Unmarked shape tolerance
The tolerance values of straightness and flatness not marked on the drawing shall be taken as Class C in Table 1 of GB1184. For specific tolerance values, see Table 7. Table 7
Measured element size L
Tolerance value
Measured element size loss
Tolerance value
>10~16
>250-400
>16~25
>400-630
>25~40
>40~63
>6301000||tt| |>63~100
>1000~1600
>100~160
>1600~2500
>160~250
>2500~4000
Note: The dimension L of the measured element in the table refers to the length dimension of the measured element for the straight line tolerance value, and refers to the larger dimension of the measured surface ratio for the flatness tolerance value. 5.1.2 The roundness tolerance value shall not be greater than half of the dimension tolerance value. 5.1.3 For cylindrical surfaces marked with?, the cylindricality shall comply with the provisions of the inclusion principle. For cylindrical surfaces not marked with?, the roundness, the straightness tolerance value of the element line and the dimension tolerance of the element are controlled respectively. 5.2 Unmarked position tolerance
5.2.1 The tolerance values of coaxiality and symmetry not marked on the drawing shall be taken according to Class C in Table 2 of GB1184. The specific values are shown in Table 8. The axis or center plane of the stable design support surface shall be selected as the reference. Table 8
Measured element size d
Tolerance value
Measured element size d
Tolerance value
>120~250
>250~500
>500~800
>10~18
>18~30
>800--1250
>30~50
>1250~-2000
>50~120
>2000-3100
5.2.2 For parallel elements marked with?, their parallelism shall comply with the provisions of the inclusion principle. For parallel elements not marked, they shall be controlled by the unmarked tolerance value of flatness or straightness and the dimensional tolerance between parallel elements respectively. 5.2.3 The vertical elements and inclined elements are controlled by the angle tolerance and the unindicated tolerance value of straightness or flatness respectively. 5.2.4 The tolerance value of circular runout and total runout shall not be greater than the combined value of the unindicated tolerance of the shape and position of the element. 4
JB/T5936-91
When the limit deviation of the center distance between any two screw and bolt holes is not indicated on the drawing, it shall be in accordance with the provisions of Table 9. Table 9
Screw or bolt center distance
Limit deviation of the center distance between any two screw holes
Limit deviation of the center distance between any two bolt holes
Screw or bolt center distance
Limit deviation of the center distance between any two screw holes
Limit deviation of the center distance between any two bolt holes
Limit deviation of the unindicated tolerance angle
>30~50
The limit deviation values of taper or slope parts are shown in Table 10. Table 10
Length dimension
Mating parts
Non-mating parts
Length dimension
Mating parts
Non-mating parts
>80~120
Note: The length values in the table are determined according to the length of the short side, thread
>120~180
>50~100
>10~18
>180~260
>10~18
>100~200
>18~30
1°30°
>260~360
The processed thread surface is not allowed to have defects such as black skin, bumps, random buckles and burrs. 7.1
The machining accuracy and surface roughness of the thread, when not specified on the drawing, shall comply with the following provisions:>30~50
>360~500
>18~30
>50~80
The accuracy of ordinary threads shall comply with the 6H and 6g grades specified in GB197. The surface roughness R. value of internal threads is 12.5μm; the surface roughness R. value of external threads is G.3um.
b. The accuracy of trapezoidal threads shall comply with the provisions of GB5976.4. The surface roughness R. value of internal threads is 6.3μm; the surface roughness R. value of external threads is 3.2μm.
7.3 The coaxiality of the external thread axis to the rod axis and the internal thread axis to the hole axis shall not be greater than half of the dimensional tolerance of the external thread major diameter and the internal thread major diameter respectively (Figure 4).
Thread finish, shoulder distance, undercut groove and chamfer shall comply with the provisions of GB3. JB/T5936-91
5 The verticality of the axis of the tapped screw hole to the end face shall comply with the provisions of Table 11. 7.5
Thread length
Tolerance value
>10~16
>16~25
>25~40
>40~63
The first circle of thread and thread teeth on the end face of the screw and rod shall be trimmed, and the end tooth thickness shall be greater than 1mm. Key and keyway
Key must comply with the provisions of GB1568.
>63~100
When the ratio of key length L to key width b is greater than or equal to 8, the flatness of the key working surface in the length direction shall comply with the following provisions, and its values are shown in Table 12.
When the key width is less than or equal to 6mm, the tolerance grade is 7. When the key width is greater than or equal to 8~36mm, the tolerance grade is 6. When the key width is greater than or equal to 40mm, the tolerance grade is 5. Table 12
Key, key length
Tolerance grade
Key, keyway length
Tolerance grade
>100~160
>10~16
>16~25
>160~250
>25~40
>250~400
The tolerance of the parallelism of the two working surfaces of the unmarked keyway shall be taken according to the tolerance grade 7 in Table 12. The symmetry of the unmarked keyway shall be taken according to the grade 9 in Appendix 4 of GB1184, and its values are shown in Table 13. Table 13
Key width b
Tolerance value
Center hole
>10~18
>18~30
>40~63
>30~50
>63~100
>400~630
>50~120
For parts not indicated in the drawing but requiring a center hole during processing, the center hole can be kept after processing without affecting the use and appearance. The center hole shall comply with the provisions of GB145.
Defects of castings and forgings in mechanical processing and their repair 10.1 Castings
Gray iron castings shall comply with the provisions of JB/T5937.
Spheroidal graphite cast iron parts shall comply with the provisions of JB/T5938, and steel castings shall comply with the provisions of JB/T5939.
High manganese steel castings shall comply with the provisions of JB/T5940. 6
JB/T5936—91
10.1.5Nonferrous alloy castings shall comply with the provisions of JB/T5941. 10.2Forgings
Forgings shall comply with the provisions of JB/T5942.
11Inspection rules
All machined parts shall be inspected and accepted by the quality inspection department of the manufacturer according to the drawings, relevant technical documents and this standard. 11.1
11.2The appearance of machined parts shall be inspected in accordance with the requirements of 3.2-3.6. 11.3The unmarked dimensional tolerances and angle tolerances of machined parts shall be inspected in accordance with the requirements of Chapter 4 and Chapter 6 respectively. 11.4The unmarked shape and position tolerances of machined parts shall be inspected in accordance with the requirements of Chapter 5. 11.5 The appearance, dimensional accuracy, geometric tolerance and surface roughness of the threads of machined parts shall be checked in accordance with the requirements of Chapter 7. 11.6 The dimensional accuracy and geometric tolerance of keys and keys shall be checked in accordance with the requirements of Chapter 8. 11.7 The geometric shape and size of major machined parts shall be checked piece by piece, and the geometric shape and size of general machined parts shall be sampled. The sampling inspection method shall be specified by the manufacturer in the product technical standards or ordering technical requirements according to GB2828 based on the batch size and quality level of the products. 12 Marking, packaging, transportation and storage
12.1 Marking
The machined parts leaving the factory shall have the manufacturer's mark. The position of the mark shall not damage the quality of the machined parts. 12.1.2
The machined parts leaving the factory shall be accompanied by a certificate of conformity or quality certificate. The following shall be indicated: manufacturer name;
part name and drawing number;
material;
date of manufacture.
12.2 Packaging, transportation and storage
The packaging, transportation and storage of machined parts shall comply with the relevant standards or order agreements. Additional remarks:
This standard was proposed and managed by the Tianjin Engineering Machinery Research Institute of the Ministry of Machinery and Electronics Industry. This standard was drafted by the Tianjin Engineering Machinery Research Institute of the Ministry of Machinery and Electronics Industry. The main drafter of this standard was Xu Xiangshan.
People's Republic of China
Mechanical Industry Standard
Engineering Machinery
General Technical Conditions for Machined Parts
JB/T593691
Published and distributed by the Machinery Standardization Research Institute of the Ministry of Machinery and Electronics Industry (PO Box 8144, BeijingWww.bzxZ.net
Copyright reserved
Postal Code 100081)
No reproduction allowed
Printed by Qinghe County Printing Factory, Hebei Province
1/16 Sheet 3/4 Number of words 14000
Format 880×1230
First edition in March 1992
First printing in March 1992
Number of copies 00.001-1000 Price 1.50 yuan
No. 0508
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