Harmonic Drive CSF-GH and CSG-GH Servo-Mount Gearheads Review: Specs, Price and Applications
Updated: 4 days ago
CSF-GH and CSG-GH are servo-mount strain-wave gearheads with a cross-roller output bearing and Quick Connect motor coupling. CSF supplies the standard-torque choice, while CSG raises the torque ratings in matched frames. Both rely on an external servo motor and drive, with the actual adapter and output arrangement selected for the application.
Quick Verdict
Consider GH when a directly mounted servo motor, supported output and compact high reduction fit the machine layout. Compare CSF and CSG using the same size, ratio and duty basis. The coupling simplifies attachment, but the shaft dimensions, motor interface and tightening procedure must still match the exact supplied gearhead.
Harmonic Drive CSF-GH and CSG-GH Servo-Mount Gearheads at a Glance
Specification | Details |
Mechanical architecture | Servo-mount strain-wave gearhead with integrated cross-roller output support |
Family ratio range | 50:1 to 160:1; select available ratio for exact frame |
CSF-20-100-GH torque | 40 Nm L10; 68 Nm L50; 82 Nm repeated peak; 147 Nm momentary peak |
CSG-20-100-GH torque | 52 Nm L10; 89 Nm L50; 107 Nm repeated peak; 191 Nm momentary peak |
Size-20 ratio-100 common entries | 90 mm frame; 1.4 kg; 1 arcmin standard accuracy |
Maximum input-speed entry | 6500 rpm for the above size-20 ratio-100 examples; duty qualifications still apply |
Output choices | Flange, smooth shaft or keyed shaft with tapped center hole, subject to ordering configuration |
Motor connection | Quick Connect coupling configured for the selected motor shaft |
Electronics | Separate motor feedback, servo drive and controller |
Price | Request a quote for complete gearhead, output and motor adapter |
Design and Engineering Assessment
The matched size-20 ratio-100 tables list CSF at 40 Nm L10 and CSG at 52 Nm L10. The corresponding L50 entries are 68 and 89 Nm, repeated peaks 82 and 107 Nm, and momentary peaks 147 and 191 Nm. Keep these four categories separate: a more favorable L50 number does not replace an L10 requirement, and a momentary entry is not a routine operating target.
Both examples list a 90 mm frame, 1.4 kg mass and 1 arcmin standard accuracy. That makes the CSG torque increase relevant in a matched package, but does not prove universal interchangeability. Confirm current dimensions, output form, motor adapter and mounting requirements rather than substituting from a shared family description.
The output bearing lets the machine load attach to a supported gearhead structure. Its radial, axial and overturning capacities are independent selection constraints. Belt preload, process forces and load overhang can govern the design even when the transmitted torque fits comfortably inside the gearing rating.
The GH name describes a motor-mount architecture, not an integrated servo actuator. Electrical compatibility, feedback protocol, fieldbus, brake control and safety functions come from the selected motor and drive. The reducer does not make an unsupported motor-drive combination compatible.
Quick Connect and the Motor Boundary
Select the motor before finalizing the adapter. Confirm shaft diameter, length, key arrangement where applicable, locating pilot and mounting pattern. Obtain the correct coupling and assembly procedure for that motor. The manufacturer’s convenient-mounting description should not be interpreted as mechanical compatibility with an arbitrary servo.
Alignment and clamp retention matter because the motor must transmit repeated reversals without slipping or creating unwanted loading. Follow the specified access and tightening sequence and confirm that the installed orientation remains serviceable after the surrounding machine is assembled.
Choosing CSF-GH or CSG-GH
Compare the torque-speed cycle using the same life and duty criteria. The verified size-20 example shows a 30% increase in rated L10 torque for CSG, along with higher repeated and momentary limits. That helps when gearing torque is the limiting factor; it does not eliminate a motor thermal limit or an output-bearing moment limit.
Do not treat source-announcement maximum torque as a value available in all five listed frame sizes or at all ratios. Select an actual row, then calculate normal load, acceleration and stop events. A compact high-ratio gearbox is still a finite-life mechanical transmission.
Output Form and Load Attachment
Flange and shaft outputs require different adjoining structures. A flange can support direct attachment of a rotary plate, while a shaft output may suit a coupling or pulley. Confirm output geometry and load location in the selected drawing before sizing the tooling support.
Combined radial, axial and moment loading must be checked with the manufacturer’s applicable method. A long cantilever can increase both bearing deflection and mounting-face loads. Strength, stiffness and positioning should be evaluated at the tooling, not only at the reducer’s nominal output interface.
Backlash, Accuracy and Axis Tuning
The zero-backlash description does not remove transmission error or elastic windup. The current size-20 ratio-100 tables list 1 arcmin standard accuracy; that remains distinct from repeatability and from the loaded axis’s final positioning behavior. Define what must be measured, under which load and in which direction.
Motor-side feedback measures input rotation. The mechanical reduction, output bearing, flange and attached tooling lie downstream. Tune with representative inertia and evaluate reversals and settling. Higher electronic gains can excite a flexible load path rather than correcting its underlying deflection.
Installation, Thermal Duty and Acceptance
The 6500 rpm maximum input entry in the selected examples is not an unrestricted continuous-speed permission. Check the gearbox duty qualifications, motor speed capability, lubrication and heat rejection for the actual cycle. Include dwell at torque, repeated accelerations and the local installation temperature.
Before production release, inspect retention, running current and temperature and compare loaded bidirectional positioning with the acceptance target. Review controlled stops and gravity holding separately. A zero-backlash reducer does not itself provide a safety-rated stop or a guaranteed non-backdrivable holding function.
Applications and Selection
Servo-driven rotary tooling, compact indexing and precision automation mechanisms
For Harmonic Drive CSF-GH and CSG-GH Servo-Mount Gearheads, 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
Motor-specific Quick Connect simplifies servo mounting
Cross-roller output support and multiple output forms offer flexible integration
CSF and CSG provide a documented matched-package torque choice
Limitations
Motor adapter and shaft compatibility require exact configuration
Rated, repeated and momentary torque limits cannot be interchanged
No included servo drive, fieldbus or machine safety function
Who Should Consider Harmonic Drive CSF-GH and CSG-GH Servo-Mount Gearheads?
machine builders matching a servo motor to a supported precision gearhead
Harmonic Drive CSF-GH and CSG-GH Servo-Mount Gearheads FAQ
Are CSF-GH and CSG-GH complete servo actuators?
No. They are gearheads designed for servo mounting. The motor, feedback, drive and control system are selected separately.
How much more torque does CSG provide in the size-20 example?
At ratio 100, the current tables list 52 Nm rated L10 for CSG-GH and 40 Nm for CSF-GH. Other sizes and ratios require their own comparison.
Can L50 torque replace the L10 requirement?
No. L10 and L50 use different life-rating criteria. Select the rating basis required for the application and apply the corresponding duty and life calculation.
Does Quick Connect fit any motor without an adapter review?
No. Confirm the motor’s shaft and mounting dimensions and obtain the correct coupling and interface. Follow the approved assembly and tightening instructions.
Which output forms are offered?
The manufacturer describes flange output, a smooth shaft and a keyed shaft with a tapped center hole. Availability and dimensions depend on the full ordering configuration.
Does zero backlash guarantee the tooling position?
No. Transmission error, torsional compliance, bearing deflection and the surrounding structure still affect the load. Verify the complete axis under representative conditions.
Can the example run continuously at 6500 rpm input?
The table identifies a maximum input-speed entry. Continuous or average operation requires the applicable thermal, lubrication and duty checks; do not assume the maximum is unrestricted continuous capability.
What should be included in a quote request?
State the CSF or CSG family, size, ratio, output form, motor model and shaft dimensions, torque-speed cycle, combined bearing loads, environment and required positioning performance.
Prices are indicative and may change. Confirm the final configuration, commercial terms and delivery schedule before ordering.
