JB/T 9317-2015 Crane Gearbox Standard Guide
JB/T 9317-2015, "Gear Reducers for Cranes — Product Standard," defines the classification, technical parameters, design requirements, test methods, and inspection rules for gear reducers used in crane applications. It applies to hardened tooth flank gear reducers installed in the hoisting and travel mechanisms of overhead and gantry cranes.
JB/T 9317-2015 is the industry standard for crane gear reducers, specifying their classification, technical requirements, test methods, and inspection rules. As the key transmission component in crane hoisting and travel mechanisms, the reducer's load-bearing capacity and reliability directly affect the crane's operational performance and safety.
Reducer Types and Drive Configurations
JB/T 9317-2015 classifies crane gear reducers into four main types: QJ, QY, ZSC, and three-in-one gear reducers. The QJ type features soft tooth flanks (gears quenched and tempered to HB280–320) and is suitable for duty classifications below A5. The QY type features hardened tooth flanks (gears carburized and quenched to HRC58–62) and offers 30%–50% higher load-bearing capacity than the QJ type, making it suitable for duty classifications of A6 and above.
The ZSC type is a vertical reducer designed for trolley travel mechanisms. The three-in-one reducer integrates the motor, brake, and gearbox into a single compact unit, simplifying installation and making it ideal for crane bridge travel mechanisms. Planetary gear reducers deliver high transmission efficiency (≥96%) in a compact footprint, making them well suited for space-constrained applications such as electric hoists.
Technical Parameters and Load Capacity
Key parameters specified in the standard: Transmission ratio range — 20 to 200 for both QJ and QY types. Input power range — 1.5 to 300 kW for QJ, 2.2 to 400 kW for QY. Center distance series — 100 to 800 mm for QJ, 112 to 900 mm for QY. Gear accuracy grade — QJ type not lower than Grade 8 (GB/T 10095), QY type not lower than Grade 7.
Load capacity requirements: Gear contact fatigue strength safety factor SH ≥ 1.25 (QJ) or ≥ 1.3 (QY). Gear bending fatigue strength safety factor SF ≥ 1.5 (QJ) or ≥ 1.6 (QY). Bearing life ≥ 10,000 hours for hoisting mechanisms or ≥ 15,000 hours for travel mechanisms. Noise limit ≤ 85 dB(A).
Shaft and Key Connection Requirements
The standard specifies the following requirements for reducer shafts and key connections: Input and output shafts must be made of alloy steel (40Cr or 42CrMo), quenched and tempered to a hardness of HB280–320. Shaft extension diameters are determined by load capacity calculations. Key connections use Type A parallel keys (GB/T 1096) made of material no lower than 45 steel. For heavy-load and frequent reversing applications, splined connections are recommended.
Bearing selection — Tapered roller bearings are used on the input and intermediate shafts (to handle combined radial and axial loads), while double-row spherical roller bearings are used on the output shaft (to handle high radial loads with minimal axial loads). Bearing fits: Shaft-to-inner-ring interference fits of k6 or m6, and bearing housing-to-outer-ring transition fits of H7 or J7.
Inspection and Testing
Factory Acceptance Test items: No-load test (run for 2 hours, checking noise, vibration, and temperature rise) and tooth contact pattern inspection (contact area ≥ 50% along tooth height and ≥ 60% along tooth length). Type tests include load testing (running at rated load with a temperature rise ≤ 65 K), efficiency measurement (≥ 92%), noise measurement, and fatigue life testing.
In-service maintenance: Initial oil change after 500 operating hours, followed by gear oil replacement every 5,000 operating hours or every 12 months, whichever comes first. Use L-CKC320/460 gear oil for soft tooth flanks and L-CKD320/460 for hardened tooth flanks. Inspect tooth flanks for pitting and wear every 2,000 operating hours. Check bearing clearance every 5,000 operating hours.
Reducer Type
QJ/QY/ZSC
Three-in-One
Tooth Surface Hardness
Soft: HB280–320
Hardened: HRC58–62
Transmission Ratio
QJ: 20–200
QY: 20–200
Load Capacity
QY 30%–50% higher than QJ
Efficiency
Planetary: ≥96%
Oil Change Interval
Initial: 500 h
Then: 5,000 h / yearly
Kelude Heavy Industry: Overhead & Gantry Crane Solutions
Kelude Heavy Industry specializes in the design, engineering, and manufacturing of heavy-duty overhead cranes and gantry cranes. Our product range covers a wide spectrum of applications, from standard industrial lifting to custom-engineered solutions for specialized processes. We focus on delivering reliable performance, long service life, and strict adherence to international safety and design standards.
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Our overhead cranes are available in single-girder and double-girder configurations, with capacities ranging from light-duty models to heavy-duty class. We also offer a comprehensive line of gantry cranes, including full-gantry, semi-gantry, and portable models. Every crane is engineered to meet specific operational requirements, ensuring optimal efficiency and safety in your facility.
| Common Crane Types | Typical Applications |
| Single-Girder Overhead Crane | Workshops, maintenance bays, light assembly |
| Double-Girder Overhead Crane | Heavy manufacturing, steel yards, foundries |
| Gantry Crane (Full/Semi) | Outdoor storage, precast concrete, shipyards |
| Portable Gantry Crane | Maintenance, loading docks, small workshops |
Key Features & Safety Compliance
Kelude cranes are built with high-quality components and incorporate advanced safety features as standard. Our designs comply with international standards including ISO 4301 for crane classification, ISO 12480 for safe use, and IEC 60204-32 for electrical equipment. We prioritize low-headroom designs, precise load control, and anti-sway technology to enhance operational safety and productivity.
Frequently Asked Questions
Q: What is the typical lead time for a custom crane?
A: Lead times vary depending on the complexity and specifications of the crane. Standard models can often be delivered within 6-8 weeks, while custom-engineered solutions may require 12-16 weeks. Contact our sales team for a specific timeline based on your project.
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Global Standards & Approvals
A: Our manufacturing processes and quality management systems align with international benchmarks. We adhere to ISO 4301 for crane classification and design principles, and our electrical systems are designed to meet IEC 60204-32 requirements. This commitment ensures that our cranes meet the high expectations of clients in the United States and Europe, including compliance with relevant local regulations and safety directives.
| Type | Tooth surface hardness | load-bearing capacity | applicable working conditions |
|---|---|---|---|
| QJ Type | soft tooth flank HB280~320 | General | A5Below Class |
| QY Type | hardened tooth flank HRC58~62 | High(Ratio QJType Height30~50%) | A6Class and Above |
| Planetary Reducer | hardened tooth flank | High | Space-Constrained Applications |
| three-in-one gear reducer | hardened tooth flank | Medium | Crane Travel Mechanism |
FAQ: Crane Gearbox Types, Maintenance & Troubleshooting
Q: What are the main types of crane gearboxes and their applications?
A: QJ series gear reducers feature soft tooth flanks (quenched and tempered to HB280–320) and are suitable for duty classifications up to A5. QY series reducers use hardened tooth flanks (carburized and quenched to HRC58–62), are rated for A6 and above, and offer 30%–50% higher load-bearing capacity than QJ units. Planetary gear reducers provide a compact structure with high efficiency (≥96%), making them ideal for electric hoists. Three-in-one geared motor units integrate the motor, brake, and reducer into a single assembly, designed specifically for Long Travel / Bridge Travel applications.
Q: What is the difference between QJ and QY series reducers?
A: QJ reducers have soft tooth flanks (quenched and tempered to HB280–320) and offer moderate load-bearing capacity and service life. QY reducers feature hardened tooth flanks (carburized and quenched to HRC58–62), delivering 30%–50% greater load capacity and 1–2 times longer service life. Select QJ for duty classifications up to A5; choose QY for A6 and above, or when lifting and transporting molten metal.
Q: What lubrication method and oil change interval should be used?
A: Splash lubrication is standard; forced lubrication is required for high-speed stages or vertical mounting. Use L-CKC320/460 gear oil for soft tooth flanks and L-CKD320/460 for hardened tooth flanks. The initial oil change should be performed after 500 operating hours, followed by replacement every 5,000 working hours or every 12 months, whichever comes first.
Q: What are common gearbox faults and how are they diagnosed?
A: Gear pitting — characterized by pockmarked flaking on tooth surfaces; inspect progression every 1,000 hours. Gear tooth breakage — shut down immediately and replace the gear. Bearing overheating — temperatures above 80°C indicate abnormal conditions. Abnormal vibration — at speeds ≤1,800 rpm, vibration values ≤0.1 mm are considered normal. Oil leakage — replace seals and inspect the breather.
