Planetary gearbox
Wanshsin WPL / WPF planetary gearbox
Economy spur-gear planetary in round (WPL) or square (WPF) flange formats, for general duty where precision is not critical.
Key specifications
| Ratio | 3–100:1 |
|---|---|
| Sizes | 042, 060, 080, 090, 115, 142 |
Series ranges as published; individual models vary. The full datasheet, drawings and CAD models are available on request.
Options
- WPL round flange
- WPF square flange
Typical applications
What a planetary gearbox is
A planetary gearbox reduces speed and multiplies torque using a central sun gear driven by the motor, several planet gears on a carrier, and an outer ring gear. Load is shared between the planets, so the gearbox is compact, coaxial and torque-dense. A single stage typically gives ratios of about 3:1 to 10:1, and stages are combined for higher ratios. Precision servo planetaries use ground helical or spur gears, preloaded output bearings and a motor adapter flange, with backlash typically a few arcminutes or less.
When engineers choose a planetary gearbox
Choose a planetary gearbox for most servo and stepper axes that need more torque, lower reflected inertia or a better inertia match. It is efficient, typically above 95% per stage, stiff and widely available in standard frames. The trade-offs are backlash, which is low but not zero, and limited single-stage ratio. For zero backlash in a compact joint, a strain-wave gear suits better. For very high shock loads, a cycloidal reducer may be more robust.
How to specify the Wanshsin WPL / WPF
Send these with your enquiry and an engineer can confirm the right WPL / WPF variant:
- Ratio and output speed (:1, rpm)
- Nominal and peak output torque (Nm)
- Emergency stop torque (Nm)
- Backlash (arcmin) and torsional stiffness (Nm/arcmin)
- Radial and axial output loads (N)
- Motor flange, shaft diameter and length (mm)
- Duty cycle, mounting orientation and lubrication
Common mistakes to avoid
- Sizing on motor torque times ratio without checking acceleration torque and service factors
- Ignoring the input speed limit at high motor speeds
- Mounting a pulley or pinion that overloads the output bearing
- Forgetting the gearbox efficiency and heat in continuous duty
Wanshsin WPL / WPF: frequently asked questions
What is the Wanshsin WPL / WPF?
Economy spur-gear planetary in round (WPL) or square (WPF) flange formats, for general duty where precision is not critical. Published series figures include ratio 3:1, ratio 100:1. It is available through our supply network, and our engineers can confirm the right variant for your application.
Who makes the Wanshsin WPL / WPF?
The Wanshsin WPL / WPF is made by Wanshsin (WANSHSIN Seikou (Hunan) Co., Ltd.) available through our supply network. Send us your requirement for pricing, lead time, datasheets and CAD.
What is the ratio of the Wanshsin WPL / WPF?
The published series minimum ratio is 3:1. Individual models and sizes in the WPL / WPF range vary, so check the exact variant against your duty cycle, mounting and environment, or ask our engineers to confirm the right size for you.
How do I choose a planetary gearbox ratio?
Start from the load speed and motor speed range, then check inertia matching and torque. A ratio that brings the reflected load inertia close to the motor inertia improves dynamics. Then confirm peak output torque during acceleration is within the gearbox rating and that input speed stays under the limit.
What backlash does a precision planetary gearbox have?
Precision servo planetary gearboxes typically have backlash from below one arcminute to several arcminutes, depending on grade and stages. Lower backlash costs more. For most positioning axes, a few arcminutes is fine; for robot joints or optics, strain-wave or zero-backlash designs are used.
Further reading: How to select a planetary gearbox · Harmonic vs planetary vs cycloidal · Gearboxes and harmonic drives
Other planetary gearbox series
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