JB/T 7935-1999 This standard is a revision of JB/T 7935-95 "Arc Cylindrical Worm Reducer", and the technical parameters have been greatly adjusted during the revision. This standard specifies the basic parameters, models, markings, dimensions, technical requirements, load capacity and selection methods of arc cylindrical worm reducers. This standard is applicable to arc cylindrical worm reducers used in various types of mechanical equipment in industries such as metallurgy, mining, lifting, transportation, construction, building materials, chemicals, energy and light industry. This standard was first issued on April 22, 1988 as GB 9147-88 and was adjusted to JB/T 7935-95 in April 1996. JB/T 7935-1999 Arc Cylindrical Worm Reducer JB/T7935-1999 Standard Download Decompression Password: www.bzxz.net

JB/T7935
This standard is a revision of JB/T7935
-95 "Arc Cylindrical Worm Reducer". Compared with JB/7935-95, the main technical content changes of this standard are as follows: the split body cover is changed to an integral body
-the two reducers with a center distance of 450.500mm are cancelled; ·The fan is added for a center distance of 63, 80.100mm;---the technical parameters have been greatly adjusted.
This standard replaces JB/17935--95 from the date of implementation. Appendix A and Appendix B of this standard are both standard requirements. This standard was proposed and submitted by the Metallurgical Equipment Standardization Technical Committee. The drafting unit of this standard: Xi'an Heavy Machinery Research Institute. The main drafters of this standard: Yang Jun, Zhao Yuliang, Chen Jianxing, Wang Yuhui, Zhang Kai. This standard was first issued in April 1988
1 Scope
Mechanical Industry Standard of the People's Republic of China
Hollow flank worm gear unitsJB/T7935
Replaces J3/T793545
This standard specifies the basic parameters, models, markings, dimensions, technical requirements, load capacity and selection of hollow flank worm gear units.
This standard is applicable to hollow flank worm gear units (hereinafter referred to as reducers) used in various types of mechanical equipment in industries such as metallurgy, mining, lifting, transportation, chemical industry, construction, building materials, energy and light industry. 2 Referenced standards
The provisions contained in the following standards constitute the provisions of this standard by reference in this standard. The versions shown are valid when this standard is published. All standards are subject to revision. Parties using this standard should explore the possibility of using the latest versions of the following standards GB191--1990 Pictorial symbols for packaging, storage and transportation
GB/T1184-1996 Tolerances of shape and position without tolerance value
GB/9439.1988
Grey iron castings
GB/T 10089--1988
GB/T 11368-1989
Precision of cylindrical worms and worm wheels
Cleanliness of gear transmission devices
GB/T 13384 1992
General Technical Conditions for Packaging of Electromechanical Products
J13/T5000.12—1998 General Technical Conditions for Heavy Machinery Coating JB/T5558--1991 Loading Test Method for Worm Reducer 3 Type, Basic Parameters and Dimensions
3.1 Type and dimensions shall conform to the provisions of Figure 1 and Table 1 respectively. 3.2 Basic Parameters
3.2.1 The center distance of the reducer shall conform to the provisions of Table 2 3.2.2 The nominal transmission ratio of the reducer shall conform to the provisions of Table 3. Approved by the State Bureau of Machinery Industry on June 28, 1999 and implemented on January 1, 2000
JB/T7935—1999
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JB/T7935
When the working environment temperature is lower than)C, the lubricating oil must be heated to ((3.2.3 Reducer T working environment temperature -40~+40C. Above or use lubricating oil with low freezing point; when the working environment temperature is higher than 40C, cooling measures must be taken 3.2.4 Reducer can run in forward and reverse directions.
3.2.5 Reducer For the load-bearing capacity, see Table A1 and Table A2 in Appendix A (Standard Appendix). 3.3 Model and marking
3.3.1 Model
Assembly type (F means with fan)
Nominal transmission ratio
Center distance, mm
Worm gear reducer with worm tooth profile ZC
3.3.2 Marking example
Example Center distance α=200mm, nominal transmission ratio i=25, the first assembly type. Arc cylindrical worm reducer CW with fan 200-25-IF JB/T 7935---19994 Technical requirementswwW.bzxz.Net
Machine and end cover
4.1.1 Cast iron parts shall be used, and their mechanical properties shall not be lower than HT200 in GB/T9439. Castings shall be aged (or annealed). 4.1.2
4.1.3 The cylindricity of the bearing hole shall not be lower than Grade 6 in GB/T1184. 4.1.4 The coaxiality of the bearing holes of the worm and worm wheel shall not be lower than Grade 6 in GB/T1184. The perpendicularity of the end face of the bearing hole to its axis shall not be lower than Grade 7 in GB/T1184. 4. 1. 5
The verticality of the axis of the bearing hole shall not be lower than Grade 7 in GB/T1184. The center distance limit deviation (± factory) shall comply with the regulations in Table 4. Table 4
Center distance &
A.2 Worm, worm wheel and worm wheel shaft
80-125
125~180
>180～250
250 317
315-40
4.2.1 The worm adopts S16MnCr forgings, and its chemical composition and mechanical properties shall comply with the provisions of Table 5 and Table 6: Other materials with equivalent or higher mechanical properties are allowed.
Chemical composition
Si6Mncr
0. 15---0. 40
S16MnCr
Heat treatment
Carburizing, annealing,
900-~1 200
JB/T7935
—1999
The worm shaft is made of 45 steel or other materials equivalent to it, with tempering hardness of 217~~255H13, 35
Tooth surface 5862HRC
Minimum core 30HRC
The worm wheel rim material is tin bronze ZQSn12-2, and its chemical composition and mechanical properties should comply with the requirements of Table 7 and Table 8. Table 7
Chemical composition
ZQSn12-2
Alloy grade
2QSn12 2
84--87
Casting method
Centrifugal iron mold casting
11~~13
The accuracy grade and backlash of worm gear transmission shall comply with 7-7-6b specified in (13T10089. Fb
100 HH
The axial pitch limit deviation of worm gear is ±F, and the cumulative tolerance of axial pitch of worm gear is x1., which shall not be lower than the grade 1 in GB/T10089. The profile tolerance of worm gear tooth m shall not be lower than grade 6 in GB/T10089. The cumulative pitch tolerance of worm wheel is ±F, and the pitch limit deviation is ±f shall not be lower than grade 7 in G13/T10089. 4.2.7
The profile tolerance of worm gear tooth shall not be lower than grade 6 in GB/T10089. The tooth thickness tolerance of worm gear tooth 7 shall comply with the provisions of Table 9. The upper deviation E of worm tooth thickness shall comply with the provisions of Table 10. Table 9
Center distance a
63-~80
80~125
>125~-180
2180~ 250
250-~315
315~400
21 ~ 3. 5
2≥ 1 ~3. 5
Jiang: Lower deviation E of worm tooth support
3. 5~～ 6. 3
3. 5 ~ 6.
≥10-16
>10㎡16
16 25
1G~~25
4.3 Complete machine
JB/T7935
4.3.1 The reducer shall comply with the provisions of this standard and shall be manufactured and inspected in accordance with the design drawings and technical documents approved by the prescribed procedures. 4.3.2
The minimum normal backlash jmin of the reducer worm pair shall comply with the provisions of Table 11. Table 11
Center distance α
80~125
Note: Minimum circumferential backlash of worm pair jitumin～jcrin/cos~125 -- 1803
7 180r 250
2503~ 315
315 -- 110
, where " is the cylindrical lead angle of the worm pitch and α is the normal angular angle of the worm. [
4.3.3 The axial clearance of the reducer input and output shafts shall comply with the requirements of Table 12. Table 12
Bearing inner diameter
Worm shaft
30~ 50
50~~80
80~120
2120~200
70~-100
100~-150
150-200
200~-250
Axial clearance
Worm gear shaft
50--100
80~~150
4.3.4 After the no-load test, check the contact spots on the worm gear tooth surface. The contact spots along the tooth length should not be less than 50%, and along the tooth height should not be less than 55%, and should be biased towards the meshing end. At least contact is allowed at the edge of the tooth and the meshing end. 4.3.5 The reducer shall not leak oil, and its cleanliness shall comply with the provisions of GB/T11368. 4.3.6 The appearance of the reducer shall be smooth and smooth, and shall not have defects such as bulges and bubbles. 4.3.7 The unprocessed inner surface of each component of the reducer shall be painted with oil-resistant paint, and the outer spray paint shall be beautiful and easy to dissipate heat. It shall comply with the provisions of JB/T5000.12.
4.3.8 Reducer noise: ≥63~100mm, ≤70dB(A); α125~180mm, 73dB(A); 200~400mm. ≤73dBA)
5 Lubrication
The reducer should use special worm gear lubricating oil. Input speed
Under normal circumstances, the lubricating oil brand can be directly selected from Table 13. Table 13
Center distance
Input speed
JB/T 7935
Continued Table 13
Center distance α
When the sliding speed of the worm gear tooth surface is greater than 10m/s, the reducer should be lubricated by oil injection. Generally, the worm gear oil with a kinematic viscosity of 220mm/s (40C) is used, and the oil injection pressure is 0.15~0.25MPa. The oil injection amount per minute should comply with the provisions of Table 14. Table 14
Center distance
Oil injection
63-100
125~140
160180
200223
250~280
315 ~ 355
Bearings generally use splash lubrication. For low-speed bearings or bearings that cannot be lubricated with oil due to structural reasons, lithium-based grease 5.3
is used for lubrication.
5.4 The temperature rise of the reducer oil pool shall not exceed 80C. The oil pool temperature shall not exceed 100 (.6 Test methods and inspection rules
6.1 The test of the reducer shall be carried out in accordance with JB/T5558. 6.2 Inspection rules
6.2.1 Each reducer shall be inspected before delivery. The inspection items shall comply with the provisions of Table 15. 6.2.2 When the following conditions are met, the reducer type inspection shall be carried out, and the inspection items shall comply with the provisions of Table 15: a) Trial determination and identification of new and old products for factory production; b) When there are major improvements in product structure, materials, and processes that may affect product performance; c) (When the national quality supervision agency proposes the requirement for type inspection, 637
Basic parameters
Structural dimensions
Precision of main components
Assembly precision
Main parts and materials
Room load and running-in test| |tt||Performance test
Fatigue performance test
Note: "+" indicates mandatory inspection items, "" indicates exempted inspection itemsJB/T7935-1999
6.3 The factory inspection and type inspection results of the reducer shall comply with the provisions of relevant technical standards and technical documents+
6.4 The sampling method and judgment rules for the inspection of the reducer shall be carried out in accordance with the relevant standards or the requirements of the type inspection unit. 7 Packaging, transportation and storage
7.1 The outer surface of the reducer shaft extension and key shall be coated with anti-rust grease and shall be tightly wrapped. 7.2 The transmission parts of the reducer shall be coated with lubricating grease. 7.3 The packaging, storage and transportation of the reducer shall comply with the provisions of GB/T13384 and GB191. 7.4 During transportation and storage, attention should be paid to waterproofing and corrosion prevention, and the reducer should be kept 1m away from the heating device. 8
Selection of reducer
The selection of reducer is shown in Appendix A.
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