Strain-wave (harmonic) gear
Harmonic Drive CSF-2A component sets strain-wave (harmonic) gear
Harmonic Drive's general-purpose cup-type strain wave gear component set. It covers sizes from tiny instrument gears to very large robot-joint units, with zero backlash.
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Select everything you need. A motor, drive and gearbox can be specified together as one axis.
Key specifications
| Rated torque (max) | 3,550 Nm |
|---|---|
| Peak torque (max) | 15,500 Nm |
| Ratio | 30–160:1 |
| Backlash (max) | 0 arcmin |
| Sizes | 8, 11, 14, 17, 20, 25, 32, 40, 45, 50, 58, 65, 80, 90, 100 |
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
Torques are for CSF-100-160 (Harmonic Drive LLC). Rated (L10) is 3550 Nm, repeated peak 9180 Nm and momentary peak 15500 Nm (the momentary peak is stored in torque_Nm_peak_max). The smallest rating is CSF-8-30 at 0.9 Nm rated. Backlash is stated only as 'zero backlash'; standard accuracy is 1–2 arcmin. Ratio 30 is offered only on sizes 8–32. The page gives no input speed or bore. Variants include CSF-2A-LW, -2XH, -1U, -2UH, -2UP, -ULW and -GH.
Specify Motion is not affiliated with Harmonic Drive SE / Harmonic Drive LLC. Harmonic Drive and CSF-2A component sets are used only to identify the product. Comparisons use published figures; always confirm against the current datasheet.
Harmonic Drive CSF-2A component sets replacement and alternative options
Use these supply-network options as a starting point for an engineering check. We can also help source the original Harmonic Drive part. Published series figures do not establish an exact-model or drop-in replacement: confirm ratings, fit, interfaces and approvals for your application.
Ultra-flat cup-type strain-wave gear with a very short axial length, light weight and high stiffness for its size.
| Published maximum | CSF-2A component sets | LCD |
|---|---|---|
| Rated torque | 3,550 Nm | — |
| Peak torque | 15,500 Nm | — |
| Ratio (max) | 160:1 | 500:1 meets or exceeds |
| Backlash (lower is better) | 0 arcmin | — |
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 | CSF-2A component sets | LCS / LCSG |
|---|---|---|
| Rated torque | 3,550 Nm | — |
| Peak torque | 15,500 Nm | — |
| Ratio (max) | 160:1 | 500:1 meets or exceeds |
| Backlash (lower is better) | 0 arcmin | — |
Ultra-flat hollow-shaft strain-wave gear, combining a very low axial height with a through-bore for wiring.
| Published maximum | CSF-2A component sets | LHD |
|---|---|---|
| Rated torque | 3,550 Nm | — |
| Peak torque | 15,500 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.
Harmonic Drive CSF-2A component sets model codes
Published model codes in the CSF-2A component sets range, with key figures from the manufacturer's data. Search this page for your part number, or send it to us for availability or an equivalent.
Typical applications
What a strain-wave (harmonic) gear is
A strain-wave gear, often called a harmonic gear, reduces speed using three parts: an elliptical wave generator, a thin flexible toothed cup or hat called the flexspline, and a rigid circular spline with internal teeth. The wave generator deforms the flexspline so its teeth engage the circular spline at two points. Because the flexspline has typically two fewer teeth, each input turn advances it slightly, giving ratios of about 30:1 to 160:1 in one stage, with near-zero backlash.
When engineers choose a strain-wave (harmonic) gear
Choose a strain-wave gear for compact, lightweight, high-ratio reduction with near-zero backlash, such as robot joints, cobots, medical robots, aerospace and optics. Hollow versions allow cables through the centre. The trade-offs are torsional stiffness at low load, which is lower than some alternatives, limited input speed and the risk of tooth ratcheting under overload. For shock loads and heavy base joints, cycloidal reducers are often preferred.
How to specify the Harmonic Drive CSF-2A component sets
Send these with your enquiry and an engineer can confirm the right CSF-2A component sets variant or an equivalent:
- Ratio (:1)
- Rated, peak and momentary torque (Nm)
- Input speed limits (rpm)
- Torsional stiffness (Nm/arcmin)
- Hysteresis and accuracy (arcmin)
- Component set or housed unit
- Hollow shaft diameter and output bearing loads
Common mistakes to avoid
- Exceeding momentary torque and ratcheting the teeth
- Ignoring low-load stiffness in precision control
- Poor housing tolerances for component sets
- Using the wrong lubricant or quantity
Harmonic Drive CSF-2A component sets: frequently asked questions
Can you help replace Harmonic Drive CSF-2A component sets 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 supply-network options where appropriate. We confirm compatibility and any changes needed before recommending a replacement.
What is the Harmonic Drive CSF-2A component sets?
Harmonic Drive's general-purpose cup-type strain wave gear component set. It covers sizes from tiny instrument gears to very large robot-joint units, with zero backlash. Published series figures include rated torque 3,550 Nm, peak torque 15,500 Nm, ratio 30:1, ratio 160:1. It is made by Harmonic Drive SE / Harmonic Drive LLC; Specify Motion can help source it or propose an equivalent.
What model codes are in the Harmonic Drive CSF-2A component sets range?
The CSF-2A component sets range includes CSF-8-30-2A-R, CSF-8-50-2A-R, CSF-8-100-2A-R, CSF-11-30-2A-R, CSF-11-50-2A-R, CSF-11-100-2A-R, CSF-14-30-2A-R, CSF-14-50-2A-R and 65 more. The table on this page lists each published model code with its key figures. Send us the code you use, or the one you need to replace, and our engineers will confirm availability, lead time or the closest equivalent.
Who makes the Harmonic Drive CSF-2A component sets?
The Harmonic Drive CSF-2A component sets is made by Harmonic Drive (Harmonic Drive SE / Harmonic Drive LLC) and is listed here for engineers comparing options. Specify Motion is not affiliated with Harmonic Drive SE / Harmonic Drive LLC; brand names are used only to identify the product.
What is the rated torque of the Harmonic Drive CSF-2A component sets?
The published series maximum rated torque is 3,550 Nm. Individual models and sizes in the CSF-2A component sets 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 Harmonic Drive CSF-2A component sets?
We can assess suitable replacement options. On published figures, LeaderDrive LCD and LeaderDrive LCS / LCSG are options to assess from our supply network. An engineer confirms the fit against your application before recommending anything.
Why do strain-wave gears have near-zero backlash?
The flexspline teeth are preloaded into the circular spline teeth by the elliptical wave generator, and many teeth engage at once. There is no clearance between teeth at the engagement zones, so backlash is close to zero. Lost motion comes mainly from elastic deflection.
What is the difference between a strain-wave component set and a housed unit?
A component set is the wave generator, flexspline and circular spline, which the machine builder mounts in its own housing with bearings. A housed unit adds a housing, output bearing and seals. Component sets save weight and space; housed units are easier to integrate.
Further reading: Harmonic vs planetary vs cycloidal · How to select a gearbox · Gearboxes and harmonic drives
Other strain-wave (harmonic) gear series
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