Strain-wave (harmonic) gear
Harmonic Drive SHD-2SH gear units
A short, flat hollow-shaft strain wave gear unit with an output bearing. It is about half the length of SHG/HFUS units, for slim rotary axes.
Key specifications
| Bore (max) | 40 mm |
|---|---|
| Rated torque (max) | 185 Nm |
| Peak torque (max) | 700 Nm |
| Ratio | 50–160:1 |
| Backlash (max) | 0 arcmin |
| Sizes | 14, 17, 20, 25, 32, 40 |
Summarised in our own words from Harmonic Drive SE / Harmonic Drive LLC's published data; series maxima, individual models vary. Last checked 2026-10-29. Source 1 · Source 2
Notes on this data
Harmonic Drive LLC lists ratios 50/80/100 with maxima at SHD-40-100: rated 185 Nm, repeated peak 398 Nm and momentary peak 700 Nm. Harmonic Drive SE lists ratios 50–160, repeatable peak torque of 12–453 Nm, a hollow shaft of 11–40 mm and a tilting moment of 37–424 Nm. SHD-2UH-LW is also listed by LLC. Accuracy is 1–1.5 arcmin.
Specify Motion is not affiliated with Harmonic Drive SE / Harmonic Drive LLC. Harmonic Drive and SHD-2SH gear units are used only to identify the product. Comparisons use published figures; always confirm against the current datasheet.
Typical applications
Alternatives that meet or exceed these figures
Engineers often come to us with a Harmonic Drive part number and leave with an alternative that is easier to source, quicker to deliver or a better fit for the machine. These 3 series from our supply network are the closest match on published figures.
Cup-type strain-wave gear component sets for building your own joint; the LCSG high-torque version lifts capacity by around 30% over the standard LCS.
| Published maximum | SHD-2SH gear units | LCS / LCSG |
|---|---|---|
| Rated torque | 185 Nm | — |
| Peak torque | 700 Nm | — |
| Ratio (max) | 160:1 | 500:1 meets or exceeds |
| Backlash (lower is better) | 0 arcmin | — |
Hollow-shaft strain-wave gear units with a large central bore for routing cables and services; LHSG is the high-torque version (over 30% more torque).
| Published maximum | SHD-2SH gear units | LHS / LHSG |
|---|---|---|
| Rated torque | 185 Nm | — |
| Peak torque | 700 Nm | — |
| Ratio (max) | 160:1 | 500:1 meets or exceeds |
| Backlash (lower is better) | 0 arcmin | — |
Ultra-flat cup-type strain-wave gear with a very short axial length, light weight and high stiffness for its size.
| Published maximum | SHD-2SH gear units | LCD |
|---|---|---|
| Rated torque | 185 Nm | — |
| Peak torque | 700 Nm | — |
| Ratio (max) | 160:1 | 500:1 meets or exceeds |
| Backlash (lower is better) | 0 arcmin | — |
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.
Other strain-wave (harmonic) gear series
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