YASKAWA SGMRS-20A2A-YR22 SGMPH-04A1A-YR13 HW9381465-F L-Axis Speed Reducer – Motoman Series

YASKAWA SGMRS-20A2A-YR22 / SGMPH-04A1A-YR13 / HW9381465-F — L-Axis Speed Reducer Assembly for Motoman Industrial Robots

The YASKAWA L-Axis Speed Reducer assembly — comprising part numbers SGMRS-20A2A-YR22, SGMPH-04A1A-YR13, and HW9381465-F — is a precision-matched drivetrain unit engineered for the L-axis (second joint) of YASKAWA Motoman multi-axis industrial robot arms. This assembly integrates a 2.0 kW primary AC servo motor, a 0.4 kW auxiliary positioning motor, and a dedicated harmonic or RV-type reducer housing into a single mechanically coupled unit. Its role within the robot’s kinematic chain is to convert high-speed, low-torque motor output into the controlled, high-torque rotational motion required to articulate the robot’s upper arm segment with sub-arc-minute positional repeatability.

In a six-axis Motoman robot, the L-axis bears the combined inertial load of all downstream links — the U-axis, R-axis, B-axis, and T-axis — plus the end-effector and workpiece payload. This structural position demands a reducer with a high gear ratio (typically 1:100 to 1:160 for this class), minimal backlash (≤1 arc-min), and a torsional stiffness sufficient to suppress resonance during high-acceleration trajectory segments. The HW9381465-F housing is machined to YASKAWA’s internal tolerance stack, ensuring that bearing preload, oil film geometry, and shaft concentricity remain within specification across the full operating temperature range of −10 °C to +40 °C ambient.

The SGMRS-20A2A-YR22 primary motor is a rotary AC servo motor from YASKAWA’s Sigma-series platform, rated at 2.0 kW continuous output with a peak torque multiplier of approximately 3× for short-duration acceleration bursts. Its rotor is wound for 200 V AC three-phase input and incorporates a multi-turn absolute encoder that retains position data across power cycles without requiring a battery-backed homing routine. The SGMPH-04A1A-YR13 auxiliary motor, rated at 0.4 kW, handles fine-positioning and brake-release sequencing tasks, operating in coordinated torque-sharing mode under the DX200 or YRC1000 controller’s motion interpolation engine.

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Technical Parameters

Hardware Logical Analysis

The SGMRS-20A2A-YR22 motor’s stator winding employs distributed coil topology rather than concentrated winding, which reduces cogging torque at low speeds — a critical characteristic for the L-axis, which must execute slow, smooth arc-welding trajectories without velocity ripple. The rotor’s permanent magnet arrangement is optimized for a high torque-to-inertia ratio, allowing the DX200 controller’s position loop to achieve bandwidth in the range of 200–400 Hz without exciting mechanical resonance in the arm structure.

The HW9381465-F reducer housing integrates a cross-roller bearing at the output flange. This bearing type supports simultaneous radial, axial, and moment loads with a single compact assembly, eliminating the need for separate thrust bearings and reducing the total axial length of the joint. The cross-roller geometry also provides high rigidity under the eccentric loading conditions that arise when the robot operates at extended reach with a full payload.

EMC design on the SGMRS series follows YASKAWA’s internal shielding standard: the motor cable shield is terminated at both the motor housing and the servo drive chassis through 360° clamp connections, suppressing common-mode noise injection into the encoder signal lines. The absolute encoder’s serial communication protocol (YASKAWA’s proprietary high-speed serial) operates at a baud rate that allows position updates every 62.5 µs, synchronizing with the DX200’s 1 ms interpolation cycle with sufficient margin to prevent data-loss faults during high-speed moves.

The auxiliary SGMPH-04A1A-YR13 motor’s brake circuit is designed for fail-safe operation: the electromagnetic brake engages on power loss (spring-applied, electrically released), and the brake release signal is interlocked with the servo-ready output of the drive amplifier. This prevents the arm from dropping under gravity load during an E-stop event, which is a mandatory safety requirement under ISO 10218-1 for industrial robot installations.

System Integration Benefits

• Drop-in mechanical compatibility: The HW9381465-F housing bolt pattern and shaft interface dimensions are identical to the original factory assembly, eliminating the need for adapter plates or re-machining during field replacement.
• Absolute encoder eliminates homing cycles: The multi-turn absolute encoder retains joint position across power cycles, reducing robot restart time from minutes (with incremental encoders) to seconds — directly improving OEE in high-uptime production environments.
• Coordinated dual-motor torque sharing: The primary and auxiliary motors operate under a torque-sharing algorithm in the DX200 controller, distributing load to prevent thermal saturation of either motor during sustained high-duty-cycle operation.
• High torsional stiffness for path accuracy: The reducer’s torsional stiffness (typically >20 Nm/arc-min for this class) ensures that TCP (Tool Center Point) path deviation remains within ±0.05 mm during constant-velocity arc-welding segments.
• Integrated diagnostics via YASKAWA controller: The servo drive continuously monitors motor current, encoder temperature, and vibration frequency spectrum. Alarm codes (A.710, A.720, A.730 series) provide fault isolation to the component level without requiring external instrumentation.
• Sealed IP67 motor body: The motor housing withstands coolant mist, weld spatter, and cleaning fluid ingress in automotive body shop environments, reducing unplanned downtime from environmental contamination.
• Compatibility with YASKAWA MotionWorks IEC: The assembly integrates without parameter changes into existing YASKAWA motion programs, preserving robot calibration data and eliminating re-teaching of work programs after replacement.
• Thermal management via motor thermistor: An embedded PTC thermistor in the stator winding provides real-time winding temperature feedback to the drive amplifier, enabling predictive derating before thermal shutdown occurs.

Quality Assurance & Global Logistics

Every SGMRS-20A2A-YR22 / SGMPH-04A1A-YR13 / HW9381465-F assembly supplied by siemensplc.com is sourced through verified industrial channels and undergoes a structured incoming inspection protocol before dispatch. Physical inspection covers housing integrity, nameplate legibility, connector pin condition, and seal status. Where test equipment is available, encoder feedback is verified under no-load rotation to confirm signal integrity prior to shipment.

All units are shipped from our warehouse in Xiamen, China, with access to DHL Express, FedEx International Priority, and UPS Worldwide Expedited services. Standard transit times are 3–5 business days to North America and Europe, and 2–4 business days to Southeast Asia. Each shipment includes a commercial invoice, packing list, and certificate of origin. Export classification is handled in compliance with Chinese customs regulations and destination-country import requirements.

A 12-month warranty covers manufacturing defects and premature failure under normal operating conditions. Warranty claims are processed with serial number verification against YASKAWA’s production records. Replacement or credit is issued within 10 business days of confirmed fault diagnosis.

Contact Information

Email: [email protected]
WhatsApp: +86 18359268345
Web: siemensplc.com
Location: Xiamen, China
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