ISO 10767-3:2025

Overview

ISO 10767-3:2025 is an international standard published by the International Organization for Standardization (ISO). Titled "Hydraulic fluid power - Determination of pressure ripple levels generated in systems and components - Part 3: Method for motors," this document sets out a procedure to evaluate pressure ripple levels, source flow ripple, and source impedance for positive-displacement hydraulic motors, including bidirectional types. It applies to motors of all sizes, operating under steady-state conditions, and is relevant for frequencies between 50 Hz and 3,500 Hz. Specifically, the method focuses on measuring at the inlet port of positive-displacement hydraulic motors to assess their fluid-borne noise and vibration characteristics.

Key Topics

• Pressure Ripple Measurement: Outlines a standardized procedure to measure the fluctuating pressure signals generated by hydraulic motors.
• Source Flow Ripple and Impedance Rating: Enables quantification of the inherent flow ripple independent of system interaction, and measures the motor's source impedance.
• Motor Types: Applies to all positive-displacement motor designs, regardless of size or manufacturer, including bidirectional motors.
• Frequency Range: Methodology is valid for frequencies from 50 Hz up to 3,500 Hz.
• Test Conditions and Setup: Specifies requirements for the test rig, including fluid type, temperature, instrumentation, and test procedures to ensure repeatable and accurate results.
• Data Analysis: Includes evaluation of amplitude and phase spectra, calculation of single figures of merit (e.g., anechoic flow ripple, anechoic power), and detailed reporting requirements.

Applications

• Hydraulic Motor Design and Selection: The standard allows manufacturers and system designers to compare different motors objectively in terms of fluid-borne noise and pressure ripple generation. This assists in selecting low-vibration motors for sensitive applications.

  • Design Optimization: Engineers can evaluate the effectiveness of motor design modifications aimed at reducing pressure ripple.
  • System Integration: Hydraulic system designers can use the data to avoid selecting motors with high pressure ripple, thus improving system reliability and reducing noise-related issues.

• Testing and Quality Assurance: Testing organizations, laboratories, and OEMs use the standardized procedure to certify hydraulic motors' compliance with noise and vibration requirements.

  • Conformance Testing: Documentation ensures motors meet specific fluid power and noise criteria for market access or regulatory compliance.
  • Benchmarking: Provides clear, comparable benchmarks for motoring frequency, ripple amplitude/phase, and impedance.

• Maintenance and Troubleshooting: Identifies excessive pressure ripple sources in existing hydraulic circuits, leading to more accurate maintenance and troubleshooting.

Related Standards

• ISO 10767-1 and ISO 10767-2: Broader series covering pressure ripple determination in fluid power systems and components beyond just motors.
• ISO 5598: Defines the vocabulary for fluid power systems and components, ensuring consistent terminology.
• ISO 1219-1: Specifies graphical symbols used in hydraulic and pneumatic diagrams, aiding in the correct interpretation and implementation of test rigs.
• IEC Electropedia and ISO Online Browsing Platform: Offer accessible standardization terminology databases, supporting adoption and clarification of technical terms in fluid power and hydraulic systems.

ISO 10767-3:2025 establishes a robust, repeatable method for evaluating the pressure ripple and noise characteristics of positive-displacement hydraulic motors. This enables manufacturers, engineers, and system integrators to improve fluid power system performance, reduce unwanted noise, and enhance product reliability. Adhering to this international standard helps ensure optimal selection, integration, and ongoing performance of hydraulic motors in industrial, mobile, and specialized fluid power applications.