Harmonic Drive SHD-2SH Hollow-Shaft Simplicity Gear Units Review: Specs, Price and Applications
Updated: 4 days ago
SHD-2SH combines ultra-flat hollow-shaft strain-wave gearing with a cross-roller output bearing in a non-housed simplicity gear-unit architecture. It omits the housing and output flange of a conventional housed gear unit so the OEM can integrate the assembly more closely into its own structure. It is neither a bare gearing component set nor a complete motorized actuator.
Quick Verdict
Consider SHD-2SH for a tightly integrated hollow-shaft mechanism when the OEM can design the surrounding housing and load attachment. The supplied cross-roller bearing is valuable, but the machine structure and mounting interfaces remain part of the customer design. Select the exact ratio and frame using actual torque, bearing-load and stiffness requirements.
Harmonic Drive SHD-2SH Hollow-Shaft Simplicity Gear Units at a Glance
Specification | Details |
Product scope | Non-housed simplicity gear unit with cross-roller output support |
Not supplied as conventional housed scope | Housing and output flange require customer integration |
Routing feature | Large hollow input shaft; verify exact usable passage in drawing |
SHD-14-50-2SH | 3.7 Nm rated L10; 12 Nm repeated peak; 23 Nm momentary peak; 0.33 kg |
SHD-17-100-2SH | 16 Nm rated L10; 37 Nm repeated peak; 71 Nm momentary peak; 0.42 kg |
SHD-20-100-2SH | 28 Nm rated L10; 57 Nm repeated peak; 95 Nm momentary peak; 0.52 kg |
Size-20 ratio-100 positioning | 1 arcmin standard accuracy; 21 ×10^4 Nm/rad output moment stiffness |
Current inspected ratio rows | 50 / 80 / 100; other proposed configurations require exact confirmation |
Control boundary | External motor and drive; no native fieldbus or safety function |
Price | Request a quote including integration drawings and installation requirements |
Design and Engineering Assessment
Simplicity refers to a specific supplied mechanical scope: the reduction and precision output support are provided without the conventional housing and output flange. That allows close structural integration, but it transfers design work to the OEM. It should not be advertised as a ready-to-mount housed box or treated as a bare component set with no output support.
The SHD-20-100-2SH row lists 28 Nm rated L10, 57 Nm repeated peak and 95 Nm momentary peak at 0.52 kg. The matched CSD-20-100-2UH housed unit lists the same torque entries at 0.65 kg, but the scope and geometry differ. The 0.13 kg bare-unit difference does not predict the mass of either completed machine assembly.
The source announcement refers to additional 80:1 and 120:1 choices. The inspected current SHD-2SH table contains 50, 80 and 100 rows. Confirm a proposed 120:1 option through an exact current drawing and quotation. Neither an old announcement nor another SHD family’s ratio menu establishes availability for the selected frame.
A hollow input shaft can route services or support a coaxial mechanism. The space is useful only if the selected motor connection and customer structure preserve it. It is not an unlimited-rotation cable solution, nor a guarantee that every listed family size has the same clear bore.
Integrating the Non-Housed Assembly
Design the surrounding structure and output attachment using the exact mounting drawing. Control locating surfaces, concentricity, runout, axial positioning and fastener retention. The supplied bearing still depends on appropriate mounting support and correct assembly.
The ability to mount loads without an additional support-bearing set does not mean that any flange or housing can carry them. The customer structure must transfer bearing reactions into the machine without excessive deformation. Document the load path and make service access part of the drawing review.
Bearing Loads and Hollow-Shaft Routing
Calculate combined radial, axial and overturning loads at the actual load position. Process forces, belt tension and a cantilevered tool can impose substantial bearing demand even where gearing torque is modest. Use the manufacturer’s applicable limits and combination rules.
Route cables and tubing with their bend radius, permissible twist and maintenance access in mind. A central passage can reduce external loops, but it must remain clear throughout travel. Unlimited rotation requires a separately designed rotary connection where the application needs one.
Torque Duty and Positioning
Check the rated, repeated and momentary torque categories separately. Normal cyclic accelerations belong within the appropriate repeated-duty calculation, while exceptional stop or shock events need their own boundary. The largest published torque is not a blanket continuous capability.
Zero backlash, transmission accuracy and output stiffness describe different behavior. The current size-14 and size-17 examples list 1.5 arcmin standard accuracy, while size 20 lists 1 arcmin. Load-point motion also depends on the customer housing, bearing support and tooling compliance.
Motor, Drive and Feedback Choices
The gear unit does not select a servo motor, encoder protocol or fieldbus. Match the motor and drive to the required input torque-speed cycle and mechanical interface. Confirm brake and controlled-stop requirements separately for gravity-loaded or high-inertia axes.
Input-side feedback does not directly measure every elastic movement of the output or customer structure. Evaluate the finished axis under load and during reversals. Load-side measurement can support demanding positioning requirements, but resonance and mechanical compliance still need proper treatment.
Assembly and Acceptance
Use the approved lubrication and installation requirements for the selected configuration. Protect the mechanism from contamination through the customer’s housing design. An open integration architecture does not itself establish an environmental protection rating.
Commission the completed assembly with representative tooling. Check retention, running current, temperature and bidirectional loaded positioning, including settling. Compare measured performance with defined load-side acceptance conditions rather than only the motor encoder reading.
Applications and Selection
Tightly integrated hollow-shaft rotary axes, compact joints and coaxial automation mechanisms
For Harmonic Drive SHD-2SH Hollow-Shaft Simplicity 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 hollow-shaft layout suits close OEM integration
Cross-roller output bearing is supplied despite the non-housed architecture
Customer-designed structure can avoid redundant housing features
Limitations
OEM must engineer housing and output attachment interfaces
Hollow passage does not provide unlimited cable rotation
Duty, bearing loads and current configuration availability need exact checking
Who Should Consider Harmonic Drive SHD-2SH Hollow-Shaft Simplicity Gear Units?
OEM motion designers selecting a compact rotary reduction stage
Harmonic Drive SHD-2SH Hollow-Shaft Simplicity Gear Units FAQ
What is a simplicity gear unit?
In this family it is non-housed gearing combined with a precision cross-roller output bearing, with the conventional housing and output flange omitted for customer integration.
Does SHD-2SH include an output bearing?
Yes. It includes cross-roller output support. The customer must still provide the correct surrounding structure and mounting interfaces for the actual machine loads.
Is it the same as SHD-2UH-LW?
No. The non-housed 2SH and housed lightweight 2UH-LW constructions have different supplied scope and drawings. Do not substitute one configuration’s geometry or mass for the other.
What are the size-20 ratio-100 ratings?
The current row lists 28 Nm rated L10, 57 Nm repeated peak and 95 Nm momentary peak at 0.52 kg, with 1 arcmin standard accuracy.
Is 120:1 established for every frame?
No. An older announcement mentions additional ratios, while the inspected current table lists 50, 80 and 100. Confirm any proposed 120:1 configuration by exact current code and drawing.
Can the hollow shaft carry cables through unlimited rotation?
The bore provides routing space. Unlimited rotation requires suitable slip rings, rotary unions or another independently designed service connection; ordinary cables retain twist and bend limits.
Does zero backlash remove structural deflection?
No. Gearing elasticity, bearing deflection and the customer housing or load attachment can affect output positioning. Verify the assembled mechanism under representative loads.
What belongs in a quotation and design review?
Specify frame, ratio, motor interface, customer housing and output attachment, combined bearing loads, torque-speed duty, bore use, environment and required output accuracy. Include stop and holding requirements.
Prices are indicative and may change. Confirm the final configuration, commercial terms and delivery schedule before ordering.
