Harmonic Drive CSD-2UH Ultra-Flat Gear Units Review: Specs, Price and Applications
Updated: 4 days ago
CSD-2UH is a housed ultra-flat strain-wave gear unit with an integrated cross-roller output bearing. It suits a rotary axis where axial length is constrained and a defined output support is valuable. The housed 2UH assembly is a different purchased scope from a CSD component set or the hollow-through-bore CSD-2UF construction.
Quick Verdict
Consider CSD-2UH when short axial packaging matters and the exact torque-duty and output-bearing limits fit the mechanism. Choose by a configuration-specific table, not a generic ultra-flat headline. A compact reducer still requires a compatible motor interface, adequate mounting stiffness and a complete load-path calculation.
Harmonic Drive CSD-2UH Ultra-Flat Gear Units at a Glance
Specification | Details |
Architecture | Housed ultra-flat strain-wave gearing with cross-roller output support |
Current website ratio rows | 50 / 80 / 100 in the inspected CSD-2UH product table |
CSD-14-50-2UH | 3.7 Nm rated L10; 12 Nm repeated peak; 24 Nm momentary peak; 0.35 kg |
CSD-17-100-2UH | 16 Nm rated L10; 37 Nm repeated peak; 71 Nm momentary peak; 0.46 kg |
CSD-20-100-2UH | 28 Nm rated L10; 57 Nm repeated peak; 95 Nm momentary peak; 0.65 kg |
Accuracy examples | 1.5 arcmin for listed sizes 14 and 17; 1 arcmin for size 20 |
Size-20 output moment stiffness | 12.8 ×10^4 Nm/rad in the inspected table |
Drive and control | External motor and drive; reducer has no native control network |
Configuration boundary | 2UH housed unit; 2UF and bare CSD components require separate drawings |
Price | Request a quote for exact size, ratio and motor connection |
Design and Engineering Assessment
Axial compactness can help a tooling head or rotary positioner fit inside an otherwise restricted envelope. It can also bring the load closer to the supporting structure, but that benefit depends on the full flange and tooling arrangement. Use the assembled drawing to assess the bearing moment arm rather than assuming every ultra-flat installation has a short load path.
The CSD-20-100-2UH table lists 28 Nm rated L10, 57 Nm repeated peak and 95 Nm momentary peak at 0.65 kg. Those limits describe different operating events. A normal repeated acceleration should not be justified solely by the larger momentary figure.
The source announcement mentions additional 80:1 and 120:1 ratios, while the inspected current product table exposes 50, 80 and 100 rows. The page also contains inconsistent generic range text. Treat a proposed 120:1 or other ratio as requiring an exact current drawing and quotation, rather than transferring the announcement to every size.
The CSD name also appears on bare component sets and other gear-unit constructions. Similar reduction technology does not establish identical included bearings, flange geometry or bore access. The complete ordering code determines what the OEM receives and what remains to be designed.
What the Housed 2UH Unit Supplies
The integrated output bearing provides a defined route for the rotating load into the gear-unit mounting. That can reduce the amount of custom bearing architecture required compared with a bare component set. It does not remove the need for a rigid and accurately prepared machine mounting surface.
Distinguish the cross-roller output bearing from the bearing inside the wave-generator mechanism. Their functions differ: one supports the machine output load, while the other participates in the reduction. The same word bearing should not obscure which load a particular specification addresses.
Sizing Torque and Bearing Loads Separately
Calculate process torque, inertia-driven acceleration, gravity and stop events for the actual axis. Check the specified torque-life and duty basis, input speed and thermal conditions. The size-20 ratio-100 example provides a useful anchor, but the exact selected row must govern the design.
Evaluate radial force, axial force and overturning moment with the applicable combined-load rules. A load acting away from the output plane can produce substantial bearing moment without requiring much transmission torque. Include mounting bolts and adjoining flanges in the structural calculation.
Accuracy, Repeatability and Compliance
The current small-frame examples list 1.5 arcmin standard accuracy rather than a universal sub-one-arcminute figure. Zero backlash is a separate feature. Neither should be rewritten as a guarantee of the final tool position under arbitrary load.
Observe the output at representative torque and temperature. Transmission error, elastic windup, bearing deflection and the machine structure contribute differently to the result. A load-side encoder can measure downstream position, but the mechanical system still needs suitable stiffness and damping.
Motor and Installation Boundaries
Select the motor and drive for the required input speed, torque and feedback compatibility. The reducer has a mechanical input, not a built-in EtherCAT or CANopen interface. Mounting dimensions, shaft engagement and alignment must follow the exact supplied configuration.
Keep lubrication, sealing and environment requirements explicit. A compact general-purpose gear unit is not automatically suitable for washdown, vacuum or contamination-sensitive use. Obtain the relevant manufacturer-approved construction and instructions when those conditions apply.
Choosing Between CSD and Other Compact Gear Units
Compare axial length, mounting envelope, bearing capacity, torque duty and total assembly mass together. CSD-2UH provides a housed ultra-flat choice, while CSF-2UH offers a different package and torque table. A hollow-shaft application may instead need an appropriate 2UF or SHD construction.
At acceptance, verify running current, temperature, noise, retention and bidirectional loaded positioning. Perform the evaluation with the intended tooling installed. For vertical or gravity-loaded axes, review the brake and stop design independently of reduction ratio.
Applications and Selection
Axially constrained rotary tooling, compact indexers and precision automation mechanisms
For Harmonic Drive CSD-2UH Ultra-Flat Gear Units, define the actual machine duty before selecting an ordering configuration. Include the required operating point, available installation space, environment and control interfaces. The specification table describes the product or family; the surrounding machine determines which of those features matters for the intended job.
Price and Value
Price: Request a quote for the exact configuration. Compare the product, compatible control equipment, required mechanical parts, cabling and commissioning as one installed system. A component price alone does not represent the cost of a working automation axis.
Evaluate an alternative against the same duty and acceptance criteria. Match the continuous operating requirement first, then compare transient capability, feedback, mechanical fit and support. This avoids choosing between superficially similar products whose ratings describe different operating conditions.
Pros and Cons
Advantages
Ultra-flat housed construction suits restricted axial envelopes
Integrated cross-roller bearing provides defined output support
Exact small-frame torque and accuracy data support grounded selection
Limitations
Published ratio descriptions conflict; non-table options need exact confirmation
Bearing loads and housing support remain separate from gear torque
External motor, control and environmental qualification are required
Who Should Consider Harmonic Drive CSD-2UH Ultra-Flat Gear Units?
OEM motion designers selecting a compact rotary reduction stage
Harmonic Drive CSD-2UH Ultra-Flat Gear Units FAQ
Is CSD-2UH a bare gearing component set?
No. It is a housed gear unit with an integrated output-bearing arrangement. A CSD component set has a different supplied mechanical scope.
Is CSD-2UH the same as CSD-2UF?
No. They are different gear-unit constructions. Use the exact drawing, especially when a hollow through bore or specific mounting geometry is required.
Which ratios were present in the current inspected table?
The inspected CSD-2UH table contained 50:1, 80:1 and 100:1 rows. Confirm any other proposed ratio with an exact current manufacturer code, drawing and quotation.
What are the size-20 ratio-100 torque limits?
The current row lists 28 Nm rated L10, 57 Nm repeated peak and 95 Nm momentary peak, with a mass of 0.65 kg. These torque categories are not interchangeable.
Does every CSD-2UH have one-arcminute accuracy?
No. The inspected size-14 and size-17 rows list 1.5 arcmin standard accuracy, while size 20 lists 1 arcmin. Use the selected configuration’s data.
Does output support eliminate load calculations?
No. Check radial, axial and overturning loads and their combinations, as well as the mounting structure and the load’s distance from the support plane.
Does the reducer include a motor controller?
No. The motor, servo drive, feedback and network interface belong to the separately selected axis-control system.
What should be specified before ordering?
Specify the exact frame and ratio, motor connection, load geometry, torque-speed cycle, bearing loads, axial envelope, environment and output-positioning acceptance requirements.
Prices are indicative and may change. Confirm the final configuration, commercial terms and delivery schedule before ordering.
