Strain-wave units and joint integration

Laifual: specify the reducer unit before designing the joint around it

Laifual's current FS product section includes FSS cup-shaped strain-wave units, with separate torque definitions and assembly variants. For a robot joint, a rotary fixture or another constrained axis, the procurement task is to match the unit's mechanical interfaces and load cycle to the surrounding structure.

Prepare your enquiry Manufacturer website ↗

Decide what the reducer unit supplies and what the joint must supply

The FSS product description identifies a cup flexspline, circular spline and wave generator, and describes a unit with crossed-roller output support. For a machine designer, that is a starting architecture. The final drawing must still identify the input connection, output flange, housing attachment and the selected variant's load-support arrangement.

Describe how the payload is attached and where its forces act. A tool mounted away from the output flange imposes an overturning moment; a direct drive torque calculation alone misses that load. Request the permissible radial, axial and moment loads for the actual assembly rather than treating the presence of an output bearing as unlimited support.

If the space claim depends on a component-set version rather than a complete unit, make that distinction explicit in the quotation. Identify which company supplies the surrounding bearings, shaft support, seals and housing, and who owns the assembly tolerances. Component dimensions and complete-unit dimensions are not interchangeable.

FSS20 at ratio 50: specify four different load quantities

The current FSS table states rated torque at 2,000 rpm input. For size 20, ratio 50, it gives these separate entries.

Official load definition	Value for FSS20 · ratio 50	Procurement use
Rated torque at 2,000 rpm input	25 Nm	Check the intended continuous operating point.
Permitted start / stop peak	56 Nm	Specify start/stop frequency and duration.
Maximum average-load torque	34 Nm	Have the supplier calculate the complete duty cycle.
Maximum momentary torque	98 Nm	Keep exceptional events separate from normal duty.

These entries come from the selected row, not the largest FS-family values. Variant-specific dimensions, weights and bearing limits still need the matching drawing.

Define the required behavior at the tool, not just at the reducer

Error budget

Give the permitted motion or positioning error at the working point. Tool offset, mounting stiffness, coupling compliance and reducer torsional deflection all affect that result. A catalog angular allowance is one contribution to the axis budget.

Test conditions

Agree load, temperature, approach direction, measurement method and cycle before requesting acceptance data. Ask for the selected unit's backlash and transmission-accuracy definitions rather than treating different precision figures as synonyms.

Assembly and life duty

Describe acceleration, reversals, dwell, working hours and overload events. Obtain the lubrication, fastener-tightening and alignment instructions for the selected variant. A brochure life figure cannot establish the life of an unspecified robot duty cycle.

Existing FS family record

FSS20 Cup-Type Harmonic ReducerSpecifications

The linked record retains its original FS-family scope. For the FSS20 example above, use the current FSS table and matching variant drawing; do not extend that one row across the whole FS family.

Prepare a joint assembly brief

Give Laifual the layout, load history and acceptance conditions for a specific unit.

Prepare sourcing request

Save this manufacturer first to include it in your sourcing request.

Joint or rotary-axis function, payload, center-of-gravity offsets and external radial/axial/moment loads.
Input connection, output flange, housing drawing, selected assembly variant and available envelope.
Ratio, motor speed, rated working load, start/stop and exceptional peak events with their durations.
Working-point accuracy requirement, duty hours, environment and agreed measurement conditions.
Quantity, complete order code, bearing/load documentation, assembly instructions and current contracting-company name.

Sources & review

The numeric example is an FSS20 manufacturer table row. Design and acceptance questions are editorial analysis. The securities announcement is used for a dated identity issue, not as product-test evidence.

Reviewed 8 October 2026.

Laifual · Current FSS product and technical table ↗Unit description and size-20 ratio-50 torque entries, rated at 2,000 rpm input.
Laifual · HKEX-filed announcement, 16 September 2026 ↗Company name in that filing and approved name-change procedures; effective-date statement remains separate.