JB/T 9003-2016 Three-in-One Crane Reducer Standard Guide
JB/T 9003-2016, "Three-in-One Reducers for Cranes," is the product standard governing geared motor units used in crane applications. It specifies the classification, technical requirements, test methods, and inspection rules for three-in-one reducers.
Product Structure and Key Parameters
Kelude Heavy Industry supplies three-in-one reducers manufactured in full compliance with this standard. The three-in-one reducer integrates the electric motor, gearbox, and brake into a single compact unit, offering a space-saving design, easy installation, and high transmission efficiency. The motor is a conical rotor type, the gearbox uses planetary gear transmission, and the brake is built into the motor tail or the reducer input shaft. The standard covers a power range of 0.2–15 kW with output speeds from 15 to 150 r/min. Mounting configurations include horizontal and vertical types, with the output shaft gear engaging either a wheel or a rack on the crane rail to provide drive.
These reducers are primarily used in the Long Travel (bridge travel) and Cross Travel (trolley travel) mechanisms of overhead cranes. When the conical rotor motor is energized, the axial magnetic pull generated by the magnetic flux overcomes the spring force, allowing the rotor to shift axially while the brake releases. When power is cut off, the spring pushes the rotor back, engaging the brake and bringing the mechanism to a stop. This design eliminates the need for a separate brake, keeping the overall package compact. The motor features Class F insulation and IP54 protection.
The standard sets detailed requirements for the gear drive system of three-in-one reducers. Gear accuracy must meet Grade 8 or better per GB/T 10095, with tooth contact pattern coverage of at least 40% along the tooth height and 50% along the tooth length. Gears are made of 20CrMnTi steel, carburized and quenched to a tooth surface hardness of HRC 58–62, with an effective case depth of 0.3–0.8 mm depending on module. Core hardness is maintained at HRC 33–48 to balance toughness and strength. The reducer gears must undergo fatigue strength verification for both tooth surface contact and tooth root bending, with a minimum safety factor of 1.5.
Three-in-one reducers are designed for a normal operating temperature range of -20°C to +40°C. For low-temperature environments (below -20°C), a low-temperature gear oil should be used to prevent solidification. In high-temperature conditions, a high-viscosity-index lubricant is recommended to maintain adequate oil film strength. During installation, the coaxiality between the output shaft and the driven wheel shaft must not exceed 0.2 mm; otherwise, additional bending moments may cause premature bearing failure. Base mounting bolts should be tightened with a torque wrench to the torque values specified in the instruction manual.
Technical Performance Requirements
Transmission efficiency is at least 96% for single-stage planetary reducers, 93% for two-stage units, and 88% for three-stage units. Efficiency losses mainly stem from gear mesh friction, bearing friction, and oil churning losses. Using high-precision gears (Grade 6–7) and the appropriate lubricant viscosity can improve efficiency. Reducer noise is limited to 75 dB(A) or less, with a temperature rise not exceeding 60 K. Gears are made of 20CrMnTi steel, carburized and quenched to HRC 58–62. Lubrication is by oil bath, with L-CKD220 industrial gear oil recommended.
Full range coverage
Application-matched
Three-stage ≥88%
Smooth operation
Continuous duty
HRC 58–62
| Model | Power(k W) | Output Rotational speed | Torque(N·m) | transmission ratio |
|---|---|---|---|---|
| QS-05S | 0.2 | 60 | 32 | 23 |
| QS-10S | 0.4 | 60 | 64 | 23 |
| QS-20S | 0.8 | 60 | 127 | 23 |
| QS-30S | 1.5 | 45 | 318 | 31 |
| QS-50S | 2.2 | 45 | 467 | 31 |
Maintenance and Inspection
Change the lubricating oil after the first 100 hours of operation to remove metal particles generated during the break-in period. Under normal use, replace the oil every 1,000 working hours or every 6 months, whichever comes first. During operation, check the oil level (between the upper and lower marks on the sight glass), inspect for leaks, and watch for abnormal vibration. Relubricate the bearings with grease every 2,000 working hours. The factory routine test includes a no-load test (smooth operation, noise ≤ 75 dB), a load test (temperature rise at rated torque ≤ 60 K), and a brake test (verifying reliable braking).
| inspection items | technical requirements | Method | Cycle |
|---|---|---|---|
| No-Load Test | Smooth Operation | Visual+Auditory | factory |
| load test | rated torque | temperature rise≤60K | factory |
| brake test | Reliable Braking | Loading Testing | factory |
| Oil Change | L-CKD220 | Periodically | 1000h/6Monthly |
Mounting of the three-in-one gear reducer in the crane bridge travel mechanism — the reducer output shaft connects to the wheel axle via a gear coupling. During installation, the coaxiality between the output shaft and the wheel axle must be maintained within 0.2 mm; otherwise, additional loads will be induced, leading to premature bearing failure. The reducer base is secured to the chassis frame with bolted connections, and the mounting surface must be machined to a flatness of 0.5 mm/m or better.
Three-in-One Reducer: FAQ & Maintenance Tips
Q: What does "three-in-one" refer to in a three-in-one gear reducer?
A: The three-in-one gear reducer integrates the electric motor, gearbox, and brake into a single compact unit, offering a space-saving design, easy installation, and high transmission efficiency. The motor is a conical rotor motor, the gearbox uses planetary gear transmission, and the brake is built into the motor tail or the reducer input end.
Q: How is the three-in-one gear reducer used in cranes?
A: It is primarily used in the crane bridge travel mechanism and trolley travel mechanism. Motor power ranges from 0.2 to 15 kW, with output speeds from 15 to 150 r/min. Available in horizontal and vertical mounting types, the unit drives the crane wheel or rail pinion through the gear on the output shaft end.
Q: What is the transmission efficiency of the gear reducer?
A: A single-stage planetary reducer achieves an efficiency of ≥96%, a two-stage unit ≥93%, and a three-stage unit ≥88%. Efficiency losses result from gear mesh friction, bearing friction, and oil churning losses. Using high-precision gears (grade 6–7) and lubricating oil with the appropriate viscosity can improve efficiency.
Q: What are the maintenance points for the three-in-one gear reducer?
A: Change the gear oil after the first 100 hours of operation. Under normal conditions, replace the oil every 1,000 hours or every 6 months. L-CKD220 industrial gear oil is recommended. During operation, check the oil level (between the upper and lower marks on the oil sight glass), inspect for leaks, and monitor for abnormal vibration. Bearings should be relubricated with grease every 2,000 hours.
