Product Overview
The forklift steering gearbox is the core transmission component of the hydraulic steering system for electric and internal combustion forklifts. It converts steering wheel rotation into high-torque hydraulic pump output to drive the steering cylinders for wheel articulation. This gearbox must deliver high torque output, high transmission efficiency, bidirectional reversibility, low backlash, and withstand the frequent start-stop, forward-reverse, and impact load conditions typical of industrial vehicles.
Yubao Transmission Technology's forklift steering gearboxes deliver rated output torque ≥500N·m (peak 800N·m), transmission efficiency ≥95% (bidirectional), backlash ≤15arcmin, and IP65 protection rating. Gears use helical cylindrical design (helix angle 15°–25°) with contact ratio >2, ground to DIN Grade 6 accuracy with tooth surface roughness Ra≤0.8μm. The sealing system employs dual lip seals + labyrinth configuration, suitable for -40℃ to +90℃ wide temperature operation. Cumulative deliveries exceed 500,000 units with 30% market share, supporting internationally renowned brands.
Technical Parameters
Dimensions
| Parameter |
Symbol |
Unit |
Value/Range |
Tolerance |
Notes |
| Overall Length |
L |
mm |
200–400 |
±2 |
Varies with ratio and structure |
| Overall Width |
W |
mm |
150–300 |
±2 |
Including mounting flange |
| Overall Height |
H |
mm |
180–350 |
±2 |
Including output shaft height |
| Center Height |
— |
mm |
80–160 |
±0.1 |
Output shaft center to mounting face |
| Weight |
— |
kg |
10–30 |
±10% |
Including lubricant |
Transmission Parameters
| Parameter |
Symbol |
Unit |
Value/Range |
Tolerance |
Notes |
| Input Speed |
n1 |
rpm |
≤3000 |
max. |
Motor rated speed |
| Output Speed |
n2 |
rpm |
Customized |
— |
Determined by ratio |
| Reduction Ratio |
i |
— |
10:1–50:1 |
±3% |
Per customer requirements |
| Rated Output Torque |
T2 |
N·m |
≥500 |
— |
Continuous duty |
| Max Output Torque |
T2max |
N·m |
800 |
— |
Peak/instantaneous |
| Rated Input Power |
P1 |
kW |
0.5–3.0 |
— |
Matched to motor |
| Transmission Efficiency |
η |
% |
≥95 |
≥ |
Bidirectional |
| Backlash |
jt |
arcmin |
≤15 |
≤ |
Precision grade <10′ |
Mounting & Connection
| Parameter |
Symbol |
Unit |
Value/Range |
Tolerance |
Notes |
| Mounting Dimensions |
— |
mm |
φ75–φ150 |
±0.1 |
Hole pattern/PCD |
| Input Shaft/Flange |
— |
— |
Customized |
— |
Keyway/Spline/Flange options |
| Output Shaft |
— |
— |
Spline/Keyway |
— |
Connection to hydraulic pump |
| Grease Type |
— |
— |
Mobil EP0/Lithium Grease |
— |
Long-life lubrication |
| Certification |
— |
— |
CE/ISO |
— |
Per export market requirements |
Structure & Materials
| Parameter |
Symbol |
Unit |
Value/Range |
Tolerance |
Notes |
| Housing Material |
— |
— |
Aluminum Alloy/Cast Iron |
— |
ADC12/HT250 |
| Gear Material |
— |
— |
20CrMnTi/16MnCr5 |
— |
Carburizing steel |
| Bearing Brand |
— |
— |
NSK/SKF |
— |
Input/output ends |
| Lubrication Method |
— |
— |
Grease Lubrication |
— |
Long-life maintenance-free |
| Sealing Type |
— |
— |
Dual Lip Seal + Labyrinth |
— |
Oil seal + labyrinth seal |
| Parameter |
Symbol |
Unit |
Value/Range |
Tolerance |
Notes |
| Protection Rating |
IP |
— |
IP65 |
— |
Dust-tight and water-resistant |
| Operating Temperature |
— |
℃ |
-40–+90 |
— |
Wide temperature design |
| Noise Level |
— |
dB(A) |
≤65 |
≤ |
Measured at 1m distance |
| Design Life |
— |
h |
≥10000 |
— |
Or 10 years |
| Maintenance-Free Period |
— |
h |
≥10000 |
— |
Grease lifespan |
Gear Design Features
| Design Element |
Solution |
Advantage |
| Tooth Profile |
Helical cylindrical gear, helix 15°–25° |
Contact ratio >2, smooth transmission, low noise |
| Accuracy Grade |
Ground to DIN Grade 6 |
Backlash ≤15arcmin |
| Tooth Hardness |
HRC 58–62 |
High wear resistance, long life |
| Profile Modification |
Tip/root relief |
Reduced meshing impact |
| Bearing Configuration |
Angular contact ball + deep groove ball |
Handles combined radial + axial loads |
Sealing System
| Seal Level |
Structure |
Function |
| Primary Seal |
Dual lip seals (TC/SC type) |
Main seal, prevents oil leakage |
| Secondary Seal |
Labyrinth seal structure |
Auxiliary dust/water protection |
| Breather Device |
Breather valve/cap |
Balances internal/external pressure, prevents seal overpressure |
Product Features
- High Torque Output: Rated ≥500N·m, peak 800N·m, meeting heavy forklift steering demands
- Bidirectional High Efficiency: Efficiency ≥95%, consistent forward/reverse, light steering feel
- Low Backlash: ≤15arcmin, rapid steering response, no free play sensation
- Wide Temperature Range: -40℃–+90℃ normal operation, low cold-start torque
- Extended Maintenance-Free Period: Grease life ≥10,000 hours, reducing customer operating costs
- Reliable Sealing: IP65 protection, dual seals for dusty/wet industrial environments
- 100% Testing: Every unit undergoes performance bench testing and leak testing before delivery
Quality Inspection
| Inspection Item |
Method |
Acceptance Criteria |
| Air Tightness |
Leak Tester |
Leak rate ≤0.05mL/min |
| Performance Bench |
Dedicated Test Stand |
Torque, efficiency, noise, temperature rise — full inspection |
| Backlash |
Angle Encoder |
≤15arcmin |
| Appearance |
Visual |
No dents, no leakage traces |
| Cleanliness |
Particle Count |
Meets customer-specified cleanliness level |
