Planetary gearbox
STOBER PHQ planetary gearboxes gearbox
High-torque flange-output planetary gearboxes with ratios from 5.5 to 600, permitted acceleration torque from 200 to 43,000 Nm and backlash from 1 to 3 arcmin.
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Key specifications
| Ratio | 5.5–600:1 |
|---|---|
| Backlash (max) | 3 arcmin |
| Efficiency | 90–96% |
| Torque accel max | 43,000 |
| Output | flange shaft |
Summarised in our own words from STÖBER Antriebstechnik GmbH + Co. KG's published data; series maxima, individual models vary. Last checked 2026-10-30. Source 1
Specify Motion is not affiliated with STÖBER Antriebstechnik GmbH + Co. KG. STOBER and PHQ planetary gearboxes are used only to identify the product. Comparisons use published figures; always confirm against the current datasheet.
STOBER PHQ planetary gearboxes replacement and alternative options
Use these supply-network options as a starting point for an engineering check. We can also help source the original STOBER part. Published series figures do not establish an exact-model or drop-in replacement: confirm ratings, fit, interfaces and approvals for your application.
Apex Dynamics high-precision helical planetary with a one-piece stainless planet cage and very short length; ADS adds a keyed input shaft for belt pulley or coupling drive.
| Published maximum | PHQ planetary gearboxes | AD / ADR / ADS |
|---|---|---|
| Ratio (max) | 600:1 | — |
| Backlash (lower is better) | 3 arcmin | 1 arcmin meets or exceeds |
Apex Dynamics economy planetary family (PE, PG, PA, PS, PN, PD, PL sub-series) for high-volume automation; standard backlash, inline or right-angle.
| Published maximum | PHQ planetary gearboxes | P-II / P-IIR |
|---|---|---|
| Rated torque | — | 459 Nm |
| Ratio (max) | 600:1 | 1,000:1 meets or exceeds |
| Backlash (lower is better) | 3 arcmin | — |
High-precision round-flange planetary with high input speed capability and near-zero backlash, aimed at robotics and CNC.
| Published maximum | PHQ planetary gearboxes | WAE |
|---|---|---|
| Ratio (max) | 600:1 | — |
| Backlash (lower is better) | 3 arcmin | 2 arcmin meets or exceeds |
Figures are the highest published for each series and are not always measured the same way. A higher figure is not automatically a better choice: mounting, duty cycle, feedback, connectors and approvals matter too. An engineer will check the fit against your application before recommending anything.
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 STOBER PHQ planetary gearboxes
Send these with your enquiry and an engineer can confirm the right PHQ planetary gearboxes variant or an equivalent:
- 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
STOBER PHQ planetary gearboxes: frequently asked questions
Can you help replace STOBER PHQ planetary gearboxes or source the original?
Send the full model code, quantity and required date. Our engineers can check original-part availability and assess suitable alternatives, including Motion Control Products options where appropriate. We confirm compatibility and any changes needed before recommending a replacement.
What is the STOBER PHQ planetary gearboxes?
High-torque flange-output planetary gearboxes with ratios from 5.5 to 600, permitted acceleration torque from 200 to 43,000 Nm and backlash from 1 to 3 arcmin. Published series figures include ratio 5.5:1, ratio 600:1, backlash 3 arcmin. It is made by STÖBER Antriebstechnik GmbH + Co. KG; Specify Motion can help source it or propose an equivalent.
Who makes the STOBER PHQ planetary gearboxes?
The STOBER PHQ planetary gearboxes is made by STOBER (STÖBER Antriebstechnik GmbH + Co. KG) and is listed here for engineers comparing options. Specify Motion is not affiliated with STÖBER Antriebstechnik GmbH + Co. KG; brand names are used only to identify the product.
What is the ratio of the STOBER PHQ planetary gearboxes?
The published series minimum ratio is 5.5:1. Individual models and sizes in the PHQ planetary gearboxes 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.
Is there an alternative to the STOBER PHQ planetary gearboxes?
We can assess suitable replacement options. On published figures, APEX Dynamics AD / ADR / ADS and APEX Dynamics P-II / P-IIR are options to assess from our supply network. An engineer confirms the fit against your application before recommending anything.
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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Tell us how you use the STOBER PHQ planetary gearboxes: the load, speed, duty and environment. Our engineers will confirm whether it is still the right part, find it for you, or propose an alternative that fits better.
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