Strain-wave (harmonic) gear
LeaderDrive LHD strain-wave (harmonic) gear
Ultra-flat hollow-shaft strain-wave gear, combining a very low axial height with a through-bore for wiring.
Key specifications
| Ratio | 30–500:1 |
|---|
Series ranges as published; individual models vary. The full datasheet, drawings and CAD models are available on request.
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 LeaderDrive LHD
Send these with your enquiry and an engineer can confirm the right LHD variant:
- 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
LeaderDrive LHD: frequently asked questions
What is the LeaderDrive LHD?
Ultra-flat hollow-shaft strain-wave gear, combining a very low axial height with a through-bore for wiring. Published series figures include ratio 30:1, ratio 500:1. It is available through our supply network, and our engineers can confirm the right variant for your application.
Who makes the LeaderDrive LHD?
The LeaderDrive LHD is made by LeaderDrive (Leader Harmonious Drive Systems Co., Ltd.) available through our supply network. Send us your requirement for pricing, lead time, datasheets and CAD.
What is the ratio of the LeaderDrive LHD?
The published series minimum ratio is 30:1. Individual models and sizes in the LHD 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.
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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