Harmonic Drive HPG-RA Right-Angle Planetary Gearheads Review: Specs, Price and Applications
Updated: 4 days ago
HPG-RA is a right-angle planetary gearhead with a load-supporting cross-roller output bearing and motor-mounting options. It belongs to Harmonic Drive’s planetary range, rather than its strain-wave component sets. Three frame sizes, configuration-specific reduction ratios and distinct output styles let a designer redirect the motor axis while keeping the load close to a supported output.
Quick Verdict
Consider HPG-RA for an automation axis that needs a right-angle motor arrangement, low planetary backlash and substantial output-load support. Size it from the full torque-duty and bearing-load requirements. The 150–2200 Nm family headline describes repeated peak torque across different configurations; it does not describe continuous torque or a single gearbox covering the entire range.
Harmonic Drive HPG-RA Right-Angle Planetary Gearheads at a Glance
Specification | Details |
Architecture | Right-angle planetary gearhead; external motor and drive |
Frame sizes | HPG-32A / HPG-50A / HPG-65A |
Ratio scope | Overall family 5:1 to 50:1; available ratios differ by frame |
Backlash | Manufacturer RA product table: less than 3 arcmin |
Output support | Integrated cross-roller bearing |
Output choices | Flange; smooth shaft; keyed shaft with tapped center hole, subject to configuration |
HPG-32A-5-RA3 | 66 Nm L10; 120 Nm L50; 150 Nm repeated peak; 200 Nm momentary peak |
HPG-32A-5-RA3 additional entries | 6000 rpm maximum input; 4 arcmin standard accuracy; 6 kg mass |
HPG-65A-50-RA5 | 750 Nm L10; 1650 Nm L50; 2200 Nm repeated peak; 4500 Nm momentary peak |
HPG-65A-50-RA5 additional entries | 3000 rpm maximum input; 3 arcmin standard accuracy; 50 kg mass |
Motor interface | Quick Connect coupling with configuration-specific mounting requirements |
Price | Request a quote for frame, ratio, output and motor adapter |
Design and Engineering Assessment
The HPG-32A-5-RA3 row separates four torque terms that are easy to collapse in a headline. It lists 66 Nm rated L10, 120 Nm rated L50, 150 Nm repeated peak and 200 Nm momentary peak. These are not alternative labels for one continuous capability. Use the manufacturer’s corresponding life and duty definitions, rather than selecting whichever number appears most favorable.
The larger HPG-65A-50-RA5 row lists 750 Nm L10, 1650 Nm L50, 2200 Nm repeated peak and 4500 Nm momentary peak. The 2200 Nm endpoint therefore refers to repeated peak, while the emergency or exceptional limit is different again. A machine that applies high torque through much of every cycle needs a duty calculation, not just a comparison to the family’s largest peak.
The cross-roller output bearing can simplify supporting a flange-mounted load. Its permissible radial force, axial force and moment are still configuration-dependent constraints. A compact tooling head with a long overhang can exhaust moment capacity before reaching the gearing torque limit. Include process forces and any braking load at the actual application point.
The right-angle arrangement changes packaging and the mounting geometry around the motor. It does not make HPG-RA equivalent to the HPN-RA family. Their backlash, output support, ratings and motor interfaces must be compared using their own tables; sharing a manufacturer and an RA label is not an identity match.
Ratio Selection and Motor Speed
The overall range is 5:1 to 50:1, but each frame has its own ratio menu. The current size-32 table includes ratios such as 5, 11, 15, 21, 33 and 45; the size-65 table includes 5, 12, 15, 20, 25, 40 and 50. Confirm the exact ratio instead of assuming every integer or every family endpoint is available in each frame.
Convert required output speed to input speed using the selected ratio, then check the motor torque-speed curve and the reducer’s speed limits. A 6000 rpm maximum input entry is not permission to assume indefinite operation at that speed in any thermal environment. The motor and gearbox duty checks must describe the same cycle.
Backlash, Accuracy and Torsional Response
The product page lists backlash below 3 arcmin, while standard accuracy is a separate table field. For example, HPG-32A-5-RA3 lists 4 arcmin standard accuracy, and HPG-65A-50-RA5 lists 3 arcmin. A sub-three-arcminute backlash claim therefore must not be republished as a universal absolute-positioning guarantee.
The manufacturer describes a backlash-compensating mechanism intended to maintain low backlash over service life. That is a mechanical design feature, not a claim that the entire axis has no wear, compliance or maintenance needs. Measure output behavior under load and reversing torque, including temperature and settling effects.
Output Form and Bearing Loads
Flange output suits a directly mounted rotary structure, while shaft outputs connect differently to couplings, pulleys or other mechanisms. Choose the actual output drawing early; changing output form can alter the adjoining structure, load position and service access. Confirm which RA3 or RA5 configuration is supplied rather than inferring all geometry from the short family name.
Evaluate combined bearing loading using the specified method. Radial and axial maxima should not automatically be applied simultaneously with maximum overturning moment. For belt or pulley loads, include belt preload and operating tension; for a cantilever, include the full distance from the bearing support to the center of force.
Motor Mounting and Commissioning
Quick Connect supports convenient motor attachment, but the correct motor adapter, shaft dimensions and coupling requirements still matter. Obtain the approved motor interface and tightening procedure. An arbitrary servo motor is not mechanically compatible merely because its rated torque appears suitable.
The drive controls the motor, not an electrical interface built into the reducer. Select feedback, fieldbus, braking and safety functions in the motor-drive system. On a gravity-loaded axis, analyze holding and stop behavior separately; the existence of gear reduction does not establish a safety-rated holding function.
A Practical Acceptance Sequence
After assembly, check shaft alignment, mounting retention and free running before applying the full load. Run a representative cycle while monitoring motor current, temperature and noise. Verify bidirectional output positioning and repeatability with the intended tooling, rather than relying only on motor encoder counts.
Review the worst recurring acceleration, the highest process load and the controlled stop as separate events. Keep the application within the proper repeated and momentary boundaries, and investigate unexpected current or temperature rather than compensating immediately with more aggressive servo gains.
Applications and Selection
Right-angle servo axes, rotary tooling and supported positioning mechanisms
For Harmonic Drive HPG-RA Right-Angle Planetary 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
Right-angle packaging supports compact motor placement
Integrated cross-roller output support can simplify the surrounding mechanism
Low planetary backlash and multiple output forms suit precision automation
Limitations
Family peak torque is not a continuous rating
Frame-specific ratios, bearing loads and motor adapters require careful selection
External motor, drive and holding/safety design remain necessary
Who Should Consider Harmonic Drive HPG-RA Right-Angle Planetary Gearheads?
OEM motion-axis designers integrating a motor, reduction stage and machine load
Harmonic Drive HPG-RA Right-Angle Planetary Gearheads FAQ
Is HPG-RA a strain-wave reducer?
No. HPG-RA belongs to the manufacturer’s Harmonic Planetary range. Its right-angle planetary construction should not be described as a CSF or CSG strain-wave component set.
Is HPG-RA the same product as HPN-RA?
No. They are distinct right-angle planetary families. Compare their own torque, backlash, output support and mounting data; do not reuse one family’s specifications for the other.
What does the 150–2200 Nm headline represent?
The current RA table identifies those endpoints as repeated peak torque for different configurations. Rated L10, rated L50 and momentary peak are separate entries.
Does every frame offer ratios from 5 to 50?
No. The overall family covers 5:1 to 50:1, while individual frames have specific menus. The selected size and full ordering code determine the available ratio.
Does less than 3 arcmin backlash guarantee that absolute accuracy?
No. Backlash and standard accuracy are separate specifications. The HPG-32A-5-RA3 table lists less than 3 arcmin backlash and 4 arcmin standard accuracy.
What output arrangements are available?
The manufacturer describes flange output, a smooth output shaft and a keyed shaft with a tapped center hole. Confirm the exact configuration and drawing for the selected gearhead.
Can the output bearing carry any load within the torque rating?
No. Radial force, axial force and overturning moment have their own limits and combination rules. Torque capacity alone does not establish the permissible tooling mass or cantilever.
What information is needed for a complete quote?
Provide the frame, ratio, output form, motor model and shaft dimensions, torque-speed duty, mounting orientation and combined bearing loads. Include braking, environment and acceptance requirements for the finished axis.
Prices are indicative and may change. Confirm the final configuration, commercial terms and delivery schedule before ordering.
