High-Torque-Density Actuators

Compact QDD actuator concepts for robot joints that must balance torque, weight, thermal duty, and controllability in a limited envelope.

Target Buyer:Best for teams trying to reduce joint size or weight without losing torque-control behavior.

High-torque integrated actuator module for compact robot joints

Capability Highlights

Motor, winding, ratio, and housing review for torque density
Thermal-duty evaluation for repeated robot motion
OEM support for package-constrained robot axes

Typical Applications

Humanoid lower limbs and compact robot arms
Quadruped legs with payload and impact requirements
Battery-powered research and field robots

Engineering Focus

Torque per mass, torque per diameter, and thermal margin
Peak-current limit, copper fill, winding choice, and voltage class
Housing heat path, mounting interface, and ambient temperature

Buyer Decision Summary

A buyer should leave this page with a shortlist decision: whether this actuator family deserves a sample review, what must be measured first, and which constraints must be fixed before price comparison.

Best Evidence

Start with torque density and connect it to the real robot duty cycle instead of reviewing catalog values alone.

Primary Risk

High torque density is requested without thermal validation

Next Buyer Action

Prepare available diameter, length, and target mass plus validation targets before requesting samples or commercial terms.

How to Evaluate This Actuator Family

Use this page to turn a product family into a shortlist decision. The useful comparison is not one headline torque number; it is how the actuator behaves inside the real robot joint.

Torque density

25–50 Nm/kg for integrated QDD modules (varies by motor class)

Directly affects leg mass, robot payload, battery runtime, and joint packaging.

Thermal margin

Continuous-to-peak ratio typically 1:2.5–1:3.5

Determines whether compact packaging can survive repeated motion.

Voltage/current envelope

24V / 48V nominal, 10–40A peak per joint

Connects actuator design to the robot power system and driver limits.

Sample Validation Plan

Before a batch decision, buyers should define the evidence expected from sample review and internal testing.

Signal to Check	Review Basis	Evidence to Ask For
Torque density	25–50 Nm/kg for integrated QDD modules (varies by motor class)	Review RMS torque, mounting heat path, ambient temperature, and sample test plan before batch release.
Thermal margin	Continuous-to-peak ratio typically 1:2.5–1:3.5	Share voltage, current, driver, and bus requirements before final winding selection.
Voltage/current envelope	24V / 48V nominal, 10–40A peak per joint	Review RMS torque, mounting heat path, ambient temperature, and sample test plan before batch release.

Acceptance Thresholds to Define

Define measurable pass/fail thresholds before the sample arrives. This prevents a subjective review where one team checks torque, another checks packaging, and nobody records whether the actuator can move toward pilot build.

Torque density: Directly affects leg mass, robot payload, battery runtime, and joint packaging.
Thermal margin: Determines whether compact packaging can survive repeated motion.
Voltage/current envelope: Connects actuator design to the robot power system and driver limits.

When This Family May Not Fit

A QDD actuator family is valuable only when the application needs its trade-offs. The same module can be a poor fit when the surrounding joint requirements point in a different direction.

High torque density is requested without thermal validation: Review RMS torque, mounting heat path, ambient temperature, and sample test plan before batch release.
The actuator fits mechanically but exceeds controller current limits: Share voltage, current, driver, and bus requirements before final winding selection.

Buyer Inputs That Improve the First Reply

A complete first inquiry shortens review loops because engineering can separate fixed constraints from adjustable actuator choices.

Fixed Constraints

Available diameter, length, and target mass
Continuous and peak torque with motion duty cycle
Battery voltage, current limit, and controller strategy

Review Targets

Cooling path, mounting material, and ambient conditions
Quantity forecast and target cost constraints

Key Evaluation Matrix

Metric	Typical Range	Why It Matters
Torque density	25–50 Nm/kg for integrated QDD modules (varies by motor class)	Directly affects leg mass, robot payload, battery runtime, and joint packaging.
Thermal margin	Continuous-to-peak ratio typically 1:2.5–1:3.5	Determines whether compact packaging can survive repeated motion.
Voltage/current envelope	24V / 48V nominal, 10–40A peak per joint	Connects actuator design to the robot power system and driver limits.

Engineering Documents by RFQ

Document packages are shared after the actuator family, joint envelope, and program context are clear. Ask for available datasheets, drawings, CAD files, torque-speed notes, compliance records, or test reports during RFQ review.

Document	Status	RFQ Input Needed
Datasheet PDF	Available by actuator class review	Torque, speed, voltage, and quantity target
2D drawing	Available by mechanical envelope review	Shaft, flange, bolt pattern, and connector constraints
3D CAD / STEP / IGES	Shared when applicable after RFQ context	Joint envelope, mounting direction, and confidentiality needs
Torque-speed / thermal envelope	Program-dependent review	Duty cycle, ambient temperature, current limit, and mounting heat path
Compliance or test reports	Requestable per program when available	Destination market and required document list

How to Request CAD / Datasheets Compliance Document Scope

RFQ Checklist

Available diameter, length, and target mass
Continuous and peak torque with motion duty cycle
Battery voltage, current limit, and controller strategy
Cooling path, mounting material, and ambient conditions
Quantity forecast and target cost constraints

Risk Controls

High torque density is requested without thermal validation: Review RMS torque, mounting heat path, ambient temperature, and sample test plan before batch release.
The actuator fits mechanically but exceeds controller current limits: Share voltage, current, driver, and bus requirements before final winding selection.

Product Gallery

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Buyer FAQ

Can torque density be improved through customization?

Often yes, but the best lever depends on motor size, winding, voltage, ratio, housing, and thermal path.

Do you publish one fixed torque-density number?

No. The useful value depends on duty cycle, cooling, ratio, and control limits, so it should be reviewed per program.

Related Resources

Inquiry Email

[email protected]

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Include robot type, joint location, torque/speed/voltage targets, quantity, and destination.

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Send QDD actuator specs, STEP files, or actuator references for engineering review.