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Mechanical Industry Standard of the People's Republic of China
JB/T5615-1991
Tractor Transmission Gear
Technical Conditions
Published on September 19, 1991
Implementation by the Ministry of Machinery and Electronics Industry of the People's Republic of China on July 1, 1992
Mechanical Industry Standard of the People's Republic of China
Tractor Transmission Gear
Technical Conditions
Subject Content and Scope of Application
JB/T5615-1991
Replaces ZBT63008-88
This standard specifies the technical requirements, collection rules, marking, packaging, transportation and storage requirements for tractor transmission gears. This standard applies to involute cylindrical gears and bevel gears of tractor transmissions. It also applies to the corresponding gears of agricultural transport vehicles, combine harvesters and engineering and forestry vehicle transmissions similar to tractors. 2
Referenced standards
GB1357
GB10095bzxz.net
GB1144
GB8539
GB2828
GB11365
ZB T63 007
3 Terminology
3.1 Starting point of meshing
Involute cylindrical gear
Involute cylindrical gear
Cylindrical spur involute spline (tooth side fit)Rectangular splineDimensions, tolerances and inspection
Fit of rolling bearings with shafts and housings
Base profile tolerances
General provisions for quality inspection of gear materials and heat treatmentBatch counting sampling procedures and sampling tables (applicable to inspection of continuous batches)Accuracy of bevel and hypoid gears
Tractor spline shaft
Technical conditions
The innermost point on the tooth profile that meshes with the mating gear. 3.2 Working tooth midpoint
The center of the radial distance between the starting point of meshing on the tooth profile and the top of the tooth3.3 Shaft gear
Gear with shaft.
4 Technical requirements
4.1 Gears shall comply with the requirements of this standard and shall be manufactured in accordance with product drawings and technical documents approved through the prescribed procedures. 4.2 Materials
4.2.1 Carburizing (carbon-nitrogen co-carburizing) steels: 20Mn2, 20Cr, 20CrMn, 20CrMo, 20CrMnTi, 20CrMnMo, 19CrNi5, 20CrNiMo, 25MnTiBRe and 30CrMnTi. 4.2.2
Quenched and tempered steels: 45, 40Cr, 40Mn, 45Cr, 45Mn2, 50Mn. Low hardenability steels: 55DTi, 60DTi.
Approved by the Ministry of Machinery and Electronics Industry on September 19, 1991 and implemented on July 1, 1992
JB/T 56151991
4.2.4 Ductile iron: Rare earth magnesium-molybdenum alloy ductile iron is recommended. Note: ① Other grades of materials can be used under the condition of ensuring strength and service life. ②) For gears with precision of grade 8 or higher and complex structure, requirements for permeability and non-metallic inclusions should be put forward for steel. 4.3 Gear roughness
Steel gear roughness should generally be forged. The metal flow direction of forged roughness should conform to the shape of the part. In the tooth part, the flow direction is not allowed to be distributed parallel to the tooth width direction.
4.4 Gear module
The normal module of cylindrical gears should conform to the provisions of GB1357. 4.5 Gear Accuracy Grade
The gear accuracy grade is determined by the gear designer or the main engine manufacturer according to the use requirements and manufacturing process conditions. In the absence of special requirements, Table C1 in Appendix C (reference) can be used as the basis for determining the accuracy grade of gear tolerance groups II and III. The accuracy grade of tolerance group I can generally be the same as that of tolerance groups II and III, or one level lower or higher than that of tolerance groups II and III. Some indicators in tolerance groups II and III of low-speed and heavy-duty gears can be appropriately higher than the grade determined according to Table C1. 4.6 Gear Accuracy Requirements
4.6.1 Gear Tolerances and Limit Deviations
The manufacturing tolerances and limit deviations of cylindrical gears shall be determined based on GB10095. In view of the characteristics and use requirements of gears within the scope of application of this standard, this standard makes the following additional provisions. 4.6.1.1 It is recommended to use tooth profile modification, and the tooth profile detection line of the modified gear tooth working surface should be within the range of Figure 1 (K-shaped frame diagram). B
Starting point of engagement
4.6.1.2 Tooth tolerance F
Tooth tolerance shall comply with the provisions of GB10095. A-value increased by one level according to the gear accuracy grade B-value decreased by one level according to the gear accuracy grade 4.6.1.3The end face circular runout of the installed hub shall not be greater than the value specified in Table 1. Table 1
End face diameter of hub
>50~120
>120-250
Gear accuracy
Note: When the accuracy grades of the three tolerance groups are different, the end face circular runout value shall be determined according to the highest accuracy grade. 2
JB/T56151991
4.6.1.4When the addendum circle is not used as the measurement reference, its dimensional tolerance shall be in accordance with the value specified in Table 2. 4.6.1.5The limit deviation of the center distance of the gear box housing hole is in accordance with the value specified in Table 2. IT11 given.
Gear tolerance group II accuracy grade
Shell hole center distance limit deviation ± F
Note: When the accuracy grades of the three gear tolerance groups are different and the accuracy grades of the gear pairs in the gearbox are different, the limit deviation value is determined according to the highest accuracy grade.
4.6.1.6 Parallelism tolerance between the center lines of the gearbox housing holes The parallelism tolerance F in the x direction is the parallelism tolerance of the two center lines of the housing holes projected on their reference plane (the plane passing through the ideal positions of the two center lines).
Where: F: Tooth tolerance of the i-th gear, μm. The value is taken according to the highest accuracy grade of the meshing gears between the two shafts; the number of gears on the shaft between the bearing holes. When the shaft span is the same, n takes the larger one. (1)
The parallelism tolerance F in the y direction is the parallelism tolerance of the two center lines of the housing holes projected on a plane perpendicular to its reference plane and parallel to the center line of the reference hole.
The parallelism tolerance zone between the center lines of the shell holes is a quadrangular prism with a positive cross-section size of F×F. (2)
When it is inconvenient to specify the above tolerance value with a quadrangular prism tolerance zone in design, processing or inspection, a cylindrical tolerance zone with a diameter of F. can be used instead of the quadrangular prism tolerance zone.
F. =0.85Fx
4.6.1.7 The manufacturing tolerance and limit deviation of bevel gears shall be determined in accordance with GB11365. 4.6.2 Gear accuracy inspection
4.6.2.1 The accuracy inspection items of cylindrical gears shall be determined in accordance with GB10095. (3)
The accuracy of the installation positioning benchmark of the finished gear should also be used as an accuracy inspection item. The end face runout of the finished gear hub that is not used for installation and positioning may not be inspected.
4.6.2.2 When using a double-sided meshing instrument to conduct a comprehensive inspection of gears, in order to fully reveal the tooth profile error, the inspection meshing angle and the cutting meshing angle must differ by an angle △α
where: k is the number of indexing worm heads of the gear cutting machine; 22 is the number of indexing worm teeth of the gear cutting machine.
If limited to existing equipment, the meshing angle must be equal to the meshing angle of the cutting teeth when checking, and the "radial comprehensive tolerance of one tooth" should be multiplied by 0.8. 4.6.2.3 When checking the tooth profile error, the radius of curvature or the development angle of the involute starting point shall be calculated according to Appendix A (Supplement). 4.6.2.4 The inspection items and inspection methods for the accuracy of bevel gears shall be determined in accordance with GB11365. 4.6.2.5 The tooth profile error and tooth direction error of the non-working surface of the gear teeth may not be checked, and the non-working surface must be marked in the working drawing. Note: In the case where the inspection means are not yet complete, the inspection can be carried out according to the requirements of the product drawing. 3
4.7 Accuracy grade and accuracy requirements of splines
JB/T56151991
4.7.1 The accuracy grade of involute splines shall be in accordance with GB3478.1. Not less than grade 6. 4.7.2 The precision of rectangular splines of grade 7, 8 and 9 gears shall comply with the general dimensional tolerance zone in GB1144; the precision of rectangular splines of grade 6 gears shall comply with the dimensional tolerance zone for precision transmission.
4.7.3 The dimensions, tolerance fit, shape and position tolerance, inspection items and inspection methods of splines on gears shall comply with the provisions of GB1144 and GB3478.1 respectively; the relevant precision requirements of splines on shaft gears shall comply with the provisions of ZBT63007. : Surface roughness
The roughness parameter values of gear tooth surfaces shall comply with Table 3. Table 3
Accuracy grade of tolerance group II
Tooth working surface roughness R
Tooth root fillet surface roughness R
The maximum allowable value of tooth surface roughness R. of meshing sleeve gear pair is 6.3μum. 4.8.2
Spline tooth surface roughness parameter values are shown in Table 4
Spline type
Rectangular spline
Involute spline
Key tooth position
Tooth end fillet surface roughness R
Surface roughness R
3The accuracy, shape and position tolerance and surface roughness parameter values of the surface matching with the rolling bearing shall be determined in accordance with GB275; the maximum allowable value of the surface roughness R of the matching surface with the oil seal 4.8.3
The maximum allowable value of the surface roughness R of the sealing lip is 0.8um. 4.9 Effective hardened layer depth of gear tooth surface
4.9.1 The nominal value of the effective hardened layer depth of the gear tooth surface of carburizing steel (carbon-nitrogen co-diffusion steel) shall be selected within the range of Table 5 without special requirements, and then the limit deviation shall be added. Gear module m
>9.5~11.0
JB/T5615-1991
Effective hardened layer depth nominal value range
0.55~0.70
0.70~0.90
0.90-1.10
1.10~1.30
1.30-1.50
1.50~1.70
1.70~1.90
Note: ①For bevel gears,
According to the midpoint normal module, the same below.
②The effective hardened layer depth of the internal gear tooth surface can be reduced according to Table 6. ③When using carbon-nitrogen co-diffusion process, the effective hardened layer depth can be reduced according to Table 6. Limit deviation
④ When using carburizing steel with high carbon content such as 25MnTiBRe and 30CrMnTi, the effective hardened layer depth can be reduced according to Table 6. For carburizing steel with lower strength and heavy-duty driving gears with a gear ratio greater than 3, the effective hardened layer depth should be increased according to Table 6. Table 6
Effective hardened layer depth adjustment value
The hardened layer depth and measurement position of quenched and tempered steel and low-permeability steel gears are shown in Table 7 and Table 8. Table 7
Normal section of gear teeth in the middle of tooth width
Direction perpendicular to tooth surface at half tooth height
Measurement position and measurement method
Radial direction of tooth bottom
Measured from the surface to 0.8 times the specified surface hardness lower limit value under a load of 9.8N by Vickers hardness method
Quenched and tempered steel
Low hardenability steel
Low tumble permeability steel
Gear module
Effective hardened layer depth
Effective hardened layer depth
(0.17~0.24)m
(0.15~0.20)m
Surface hardness
JB/T 56151991
4.10.1 The tooth surface hardness of carburized (carbon-nitrogen co-diffusion) steel general gears should be 56~64HRC, heavy-duty gears should be 59~64HRC, and the hardness difference of a single gear should not be greater than 3HRC units. The tooth surface hardness of the inner ring gear: the modulus less than 5 should not be less than 50HRC, the modulus equal to and greater than 5 should not be less than 45HRC, and the hardness difference of a single gear should not be greater than 4HRC units. 2 The tooth surface of quenched and tempered steel should generally be hardened, and the tooth surface hardness should not be less than 50HRC; the hardness of the tooth surface that does not require surface hardening should not be less than 255HB.
The hardness difference of a single gear should not be greater than 4HRC (25HB) units. The tooth surface hardness of low hardenability steel gears should not be less than 56HRC, and the hardness difference of a single gear should not be greater than 4HRC units. 4.10.3
The tooth surface hardness of ductile iron gears is 42~46HRC. 5 For large passive gears with a tooth ratio greater than or equal to 3, the tooth surface hardness can be 3~5HRC4.10.5
units lower than the tooth surface hardness of the meshing active gear. The reduction value is determined by the designer and indicated on the drawing. : Spline surface hardness: The surface hardness of the internal spline of the gear should not be less than 50HRC. For gears that are induction heated and quenched after penetration, the spline working surface hardness should be above 35HRC while ensuring the surface strength and wear resistance of Table 4.10.6
. 4.10.7
The hardness of the external spline surface of the shaft gear and the surface matching with the bearing and oil seal lip shall comply with the provisions of ZBT63007. The surface hardness of the thin-walled hollow shaft gear bearing installation part [wall thickness/(fitting diameter) less than 1/5] should not be less than 35HRC. The core hardness of carburized (carbonitriding) steel gears. The core hardness requirements of carburized (carbonitriding) gear teeth are shown in Table 9. Table 9
20CrMnMo
Gear module
Note: 1) This combination should not be selected.
20CrMo
20CrMn
20CrNiMo
20CrMnTi
19CrNi5
25MnTiBRe
The measurement position of the core hardness should be on the normal section in the middle of the tooth width, where the center line of the gear tooth intersects with the root circle. 2 Tooth metallographic structure
Martensite is not greater than level 5.
4.12.2 For other metallographic structure requirements, see Table 10. Table 10
Gear module
Sliding gear
1~5 level
1~5 level
Surface quench carbide
30CrMnTi
Fixed gear
Carbon-nitrogen co-diffusion
1~5 level
1~5 level
1~5 level
1-6 level
1-6 level
Carbon-nitrogen co-penetration
1~5 level
1-5 level
1~5 level
JB/T5615—1991
4.12.3 Black structure at the root circle of the tooth shall not have black bands when the sample is not corroded. The depth of black spots and black nets shall not exceed 0.02mm; after the sample is lightly corroded, the width of the black net shall not exceed 0.04mm. Gears with black wind width greater than 0.04 to 0.06mm and slight black bands (within 0.01mm) can be used as qualified products after strengthening shot peening at the root. 4.13 Gear heat treatment quality inspection methods, except for the rate hard layer measurement location and measurement method specified in Table 8 in Article 4.9.2 of this standard, shall comply with the provisions of GB8539 and other current relevant standards. 4.14 Surface condition of gears
The surface of the finished gears shall not have scale, cracks, scars, cracks, metal stratification and debris. 5 Appearance quality of gears
4.15.1 If the gear product drawing does not indicate that the top of the tooth is allowed to be chamfered, it shall not be chamfered. 4.15.2 There shall be no visible root digging at the root of the tooth. 4.15.3 There shall be no dents and scratches on the tooth surface and the positioning reference surfaces. 4.15.4 There shall be no intersection at the fillet of the tooth end
4.16 Reliable life of gears
The number of bending working cycles of the gears shall be greater than 3×10°, the number of contact working cycles shall be greater than 5×10°, and the reliability shall be more than 90%. 4.17
Warranty period
If the user complies with the assembly, maintenance and use rules specified in the tractor instruction manual, the warranty period shall be the same as the warranty period specified in the main engine. During the warranty period, if the gear fails due to the manufacturer's fault and cannot be used normally, the gear manufacturer shall repair, replace or return it.
5 Acceptance rules
5.1 Gears must be inspected and qualified by the manufacturer's technical inspection department before they can leave the factory. 5.2 The grade and quality of the gear steel should be inspected according to the quality assurance sheet of the steel factory or the raw material acceptance document of the gear manufacturer. 5.3 Acceptance inspection items
5.3.1 Gear accuracy (see Article 4.6.2). 5.3.2
Spline accuracy (see Article 4.7).
Surface roughness of tooth surface, tooth root fillet, spline centering surface, bearing mounting part and oil seal mating surface 5.3.3
Heat treatment quality, including tooth surface and spline surface hardness, core hardness, effective hardened layer depth and metallographic structure, bearing and oil seal sealing lip surface hardness.
5.3.5 Appearance quality (see Article 4.15).
5.4 The acceptance inspection method shall be in accordance with the relevant provisions of Article 5. 5.5 The acceptance sampling method shall be in accordance with the provisions of GB2828. 6 Marking
6.1 The gears shall generally be marked with:
a. Manufacturer name or factory mark;
b. Part number.
6.2 The location, size and method of marking shall be in accordance with the provisions of the product drawings. Care should be taken not to damage the surface of the parts and ensure that the marking remains clear and intact during the entire use period of the gears.
Packaging, transportation and storage
JB/T 56151991
7.1 Before packing, the gears must be cleaned, oil-sealed or wax-sealed, and wrapped with strong, water-proof neutral paper or plastic bags, and then packed in a cardboard box. The cardboard box should be marked with:
a. Manufacturer name, factory logo and address;
b: Main engine model, part name and part number; c. Packing date and anti-rust validity period.
7.2 The cardboard box should be accompanied by a product certificate signed by the manufacturer's technical inspector. Gears or shaft gears packed in cardboard boxes must be packed in dry packaging boxes lined with waterproof paper, and ensure that the products will not be damaged during normal transportation. The total weight after packing should not exceed 50kg. The packaging box should be accompanied by a packing list signed by the manufacturer's packer, which should indicate the product name, part number and quantity. 7.5
The outside of the packaging box should be marked with:
a. b. Name of manufacturer, factory logo and address;
b. Product name;
c. Gross weight and quantity;
d. Receiving unit and address;
e. "Handle with care", "Moisture-proof" and other signs. 7.6
If the ordering party agrees, simple packaging can be used. 7.7 Gears or shaft gears should be stored in a ventilated and dry warehouse. Under normal storage conditions, the manufacturer should ensure that the product will not rust within 12 months from the date of leaving the factory.
JB/T 56151991
Calculation method of the size of the starting point of the involute meshing of a gear pair (supplement)
The radius of curvature of the starting point of the involute meshing of a gear pair gA1.1
For external gear pairs.
o=Asinα
The external gear meshing with the internal gear is expressed by
where: A-
-Asinα
The center distance of the gear pair is replaced by the center distance of the gear box housing, and the deviation is calculated according to the following calculations; gear end face meshing angle;
Gear end face tooth angle, α, =arctg (tooth angle;
End face module, m=
Normal module;
Helix angle;
Number of teeth of the mating gear; ||tt ||The radius of the tooth top circle of the mating gear (the inner gear is a small circle) is calculated according to the upper deviation for the outer gear and the lower deviation for the inner gear; for gears that allow chamfering, r can be deducted from the height of the chamfer. The expansion angle of the starting point of the involute?
mnzcosa
In the formula:
The number of teeth of the gear under test.
Center distance of the housing hole A
>30-50
>50~80
>80~120
>120~180
>1 80~250
>250~315
Gear (midpoint) pitch circle
Working linear speed
JB/T5615-1991
Gear box housing hole center distance tolerance value
(Supplement)
Center distance limit deviation ± F
Appendix C
Basis for determining gear accuracy grade
(Reference)
Accuracy grade and working linear speed of gear tolerance group II and III Corresponding relationship of spur gear
Precision grade of tolerance group II and III
Additional notes:
Not less than grade 9
Not less than grade 8
This standard is proposed and managed by the Luoyang Tractor Research Institute of the Ministry of Machinery and Electronics Industry. This standard is drafted by the Luoyang Tractor Research Institute of the Ministry of Machinery and Electronics Industry. The main drafter of this standard is Zhou Jiliang.
>10~15
Not less than grade 7
>15-25
Not less than grade 6
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