Details

Introduction
Ultra-High Speed, Combined-Load Bearing Life Test System
In critical systems, bearings are often the weakest single point that can bring an entire machine down. A seized bearing in an aero-engine, a failed bearing in a high-speed gearbox, or a thermal runaway in a turbocharger can mean mission abort, unscheduled shutdown, or catastrophic damage. Yet, in most programmes, bearing life is still predicted largely from catalogue data, safety factors and assumptions.

The High Speed Bearing Endurance Test Rig exists to remove those assumptions.

This rig allows you to recreate the real punishment your bearings see in service—extreme speeds up to 70,000 rpm, combined radial and axial loads, controlled lubrication and elevated temperatures—and then watch, in a controlled and instrumented environment, how the bearing actually behaves and fails. Instead of trusting theoretical L10 values, you get hard evidence: how torque drifts, when vibration rises, how temperature builds, and under exactly what combination of load, speed and oil condition the bearing reaches the end of its life.

For organisations working in aerospace, defence, automotive and advanced rotating machinery, this isn’t a “nice-to-have” lab toy. It is a risk-reduction tool: it validates designs before they go into service, exposes weak suppliers, de-risks new lubricants and coatings, and gives your certification and reliability teams data that will stand up to scrutiny.

Functional Objective & Test Capability
The core purpose of this rig is to answer a fundamental question:
“How do high-speed bearings really behave over their life under my specific operating conditions?”

To serve that purpose, the test rig is engineered to:
• Measure endurance life of rolling bearings under:
  ▹ Variable radial load
  ▹ Variable axial (thrust) load
  ▹ Speeds from low rpm up to ~70,000 rpm
  ▹ Controlled lubrication flow and pressure
  ▹ Controlled oil temperature, including high-temperature endurance

• Capture and log key performance indicators throughout the test:
  ▹ Torque / friction evolution
  ▹ Speed and speed stability
  ▹ Radial and axial load levels
  ▹ Oil pressure, temperature and flow
  ▹ Vibration levels (via external analyser input)

• Enable realistic test scenarios, such as:
  ▹ Constant-load, constant-speed endurance runs
  ▹ Multi-step or ramped loads at fixed speeds
  ▹ Temperature-accelerated life tests
  ▹ Comparative tests for bearings, lubricants or coatings
The system is designed for long-duration, partially unattended testing, with adequate interlocks and monitoring to protect both the operator and the equipment.

Typical Applications
This machine is ideal for organisations that must qualify, validate or compare bearings for demanding applications:
• Aero-engine shaft and accessory gearbox bearings
• High-speed gearboxes and turbo-machinery (defence, aviation, industrial)
• Turbochargers, superchargers and high-performance automotive bearings
• Research & development facilities focusing on fatigue, lubrication and failure modes
• Qualification laboratories for new bearing designs, suppliers or production batches
In many programmes, it is used as a qualification and type-test bench before bearings are cleared for critical systems.

System Architecture – Overview
The High Speed Bearing Endurance Test Rig is built around a high-power drive train, a precision high-speed gearbox, a bearing loading fixture, and independent lubrication systems, all integrated with a PC-based control and data acquisition system.

The main subsystems are:
• High-power drive motor with vector control
• Two-stage single-helical gearbox to reach 70,000 rpm
• Bearing loading fixture with precision spindle and housing
• Radial loading using a pneumatic bellow and load cell
• Axial loading using compact pneumatic cylinders and load cells
• Bearing lubrication power pack with heating and flow control
• Gearbox lubrication system
• Instrumentation & DAQ for torque, speed, loads, pressure, temperature and flow
• Cast-iron base frame for stiffness and vibration damping
Each subsystem is designed to be robust, maintainable, and suitable for high-speed continuous operation.

Drive System & High-Speed Gearbox
At the heart of the rig is a powerful, speed-controlled drive system that delivers the mechanical conditions needed for endurance testing.

Drive Motor & Vector Control
The rig uses a 3-phase AC motor in the ~113 kW class, paired with an industrial vector control drive:
• Approximate power: 113 kW
• Supply: 415 V, 3-phase AC
• Nominal speed: ~2900 rpm, with capability up to ~5000 rpm
• Encoder feedback for closed-loop speed control
• Configurable acceleration/deceleration ramps to minimise mechanical shock

This arrangement ensures that test speed can be set, held and limited precisely, with torque monitoring and limitation built into the drive logic.

High-Speed Gearbox
To reach spindle speeds up to 70,000 rpm, the motor drives a dedicated, high-performance gearbox:
• Input speed (max): 5000 rpm
• Output speed (max): 70,000 rpm
• Gear ratio: 14 : 1
• Design: two-stage, single-helical, parallel shaft
• Design standard: AGMA 6011 I-03 (high-speed gear design)
• Bearings: hydrodynamic journal bearings with steel backing and white-metal lining
The gearbox is designed for continuous high-speed operation, with strong emphasis on low vibration and high reliability.

Coupling & Torque Limiting
Between the rotating elements:
• A torque-limiting safety coupling is installed between motor and gearbox:
  ▹ Typically set to slip at around 300 N•m to prevent damage under sudden overloads (e.g., bearing seizure or shaft lock).
• High-speed flexible couplings are used between gearbox output, torque sensor and test spindle:
  ▹ Capable of operating safely at 70,000 rpm
  ▹ Compensate for minor misalignments and reduce transmitted vibration
This layout provides both mechanical protection and measurement integrity at high speeds.

Bearing Housing, Spindle & Mechanical Structure
The bearing under test is mounted in a dedicated fixture that ensures correct fit, alignment and load introduction.

Cast-Iron Bed & Base Frame
The entire assembly (motor, gearbox, bearing fixture) is mounted on a cast-iron bed:
• High bending stiffness to maintain shaft alignment under load
• Excellent vibration damping due to the inherent properties of cast iron
• Reduced transmission of drive and gear vibrations to measurement components
This base design is essential for repeatable results and long component life.

Bearing Spindle & Housing
The bearing loading fixture consists of:
• A precision ground spindle shaft, carrying:
  ▹ The test bearing
  ▹ Supporting bearings and discs as required
• Customisable bearing discs and spacers to match the geometry of the test bearing (e.g. 20 × 47 × 14 mm, or user-specific sizes)
• A two-part housing:
  ▹ The lower housing supports the bearing discs and fixes them to the bed.
  ▹ The upper housing receives radial and axial forces from the loading mechanisms and transfers them into the test bearing.
The housing is designed with lubrication channels and sensor ports so that oil can be supplied and monitored precisely at the bearing locations.

Mounting & Dismantling
To avoid damage during mounting and demounting operations, a dedicated bearing engagement and dismantling fixture is used, ensuring:
• Correct alignment during installation
• Controlled pressing forces
• Efficient bearing changes between tests

Radial & Axial Load Application
To reproduce real-world operating conditions, the rig offers independent control of radial and axial loads.

Radial Loading
Radial load is generated using a pneumatic air bellow:
• Compressed air acts on the bellow, producing a controllable vertical force.
• This force is applied to the upper housing through a radial loading pin, resulting in radial load on the test bearing.
• A radial load cell in the force path measures the actual load applied.

Key characteristics:
• Radial load capacity: up to approx. 25 kN (≈2.5 tonnes), depending on configuration
• Smooth load adjustment by varying air pressure
• Continuous load verification via load cell output and digital indicator

Axial Loading
Axial (thrust) load is applied via compact pneumatic cylinders:
• Multiple cylinders are arranged such that their combined force acts in a pure axial direction on the bearing disc.
• One or more axial load cells measure the applied force accurately.

Typical capabilities:
• Axial load capacity: up to approx. 2.5 kN, depending on number and size of cylinders
• Configurable for pure radial, pure axial, or combined loading scenarios

Pneumatic Control
The pneumatic system includes:
• Filter-regulator units to ensure clean, dry air at stable pressure
• Electro-pneumatic (E/P) regulators which convert electrical control signals into precise pressure levels for the radial and axial actuators
• Solenoid valves (5/2 and 3/2, 24 V DC) for applying or venting pressure, extending or retracting cylinders
This allows the creation of well-defined loading profiles and enables both manual and semi-automated load control strategies.

Lubrication & Thermal Management
Lubrication and temperature control are critical to bearing life testing, and the rig treats them as first-class controlled variables.

Bearing Lubrication Power Pack
The bearing lubrication system provides oil to the test and support bearings at:
• Controlled pressure
• Controlled flow rate
• Controlled temperature

Key features:
• Oil reservoir, pump, filtration and return lines designed for continuous operation
• Electric heater capable of raising oil temperature from ambient (~35 °C) up to approximately 200 °C
• Proportional flow control valve for adjusting oil flow via electrical command

Monitored parameters include:
• Bearing oil pressure (via pressure transmitter, 4–20 mA)
• Bearing oil temperature (via temperature transmitter, typically PT100 + transmitter, 4–20 mA)
• Oil flow rate (in L/min), displayed locally and acquired by DAQ
This enables test conditions ranging from low-flow, high-temperature accelerated tests to well-lubricated, moderate-temperature endurance runs.

Gearbox Lubrication System
A separate gearbox lubrication power pack is used to:
• Supply oil to gears and journal bearings at the required pressure and flow
• Maintain a stable hydrodynamic oil film at high speed
• Protect gearbox components against wear and thermal degradation
The operating procedure ensures that gearbox lubrication is always established and stabilised before high-speed operation is permitted.

Cooling & Heat Rejection
Depending on site utilities, the lubrication systems can be connected to:
• An external chiller, or
• A cooling water circuit
to remove the generated heat and maintain the desired oil temperature during long tests.

Instrumentation, Monitoring & Data Acquisition
The rig is heavily instrumented so that each test is fully documented and traceable.
Measured Variables

Typical instrumentation includes:
• Torque: Non-contact torque sensor (0–50 N•m typical)
• Speed: Integrated with the torque sensor or dedicated pickup (0–80,000 rpm capability)
• Radial load: Measured through a radial load cell (up to ~25 kN)
• Axial load: Measured via axial load cells (up to ~2.5 kN total, depending on configuration)
• Oil pressure (bar): For bearing lubrication and, where instrumented, gearbox lubrication
• Oil temperature (°C): Bearing inlet temperature (and optionally outlet), gearbox temperature
• Flow rate (L/min): Bearing lubrication flow
• Digital status signals: Pump ON/OFF, heater ON/OFF, level switches, limit switches, emergency stops and interlocks

Local Indicators
On the front panel/control panel, digital indicators provide:
• Real-time display of torque, speed, radial load and axial load
• Display of oil pressure, temperature and flow
• Configurable alarm setpoints, allowing local trip logic for unsafe values

PC-Based Data Acquisition
A PC or industrial PC with dedicated DAQ hardware:
• Collects analogue and digital signals from all transmitters and sensors
• Displays real-time values and trends on the HMI
• Logs all relevant data to files, with time stamps and test identifiers

This creates a complete digital record for each test, supporting:
• Statistical life analysis
• Failure investigations
• Supplier comparisons
• Reporting to internal stakeholders or external agencies

Technical Specifications (Typical)
The table below summarises the typical technical specifications of the High Speed Bearing Endurance Test Rig. Values can be customised to user requirements, but this reflects a representative configuration.

  

    

      
Parameter
      
Specification (Typical)
    

    

      
Application
      
Endurance and performance testing of high-speed rolling bearings
    

    

      
Test bearing speed range
      
0 to 70,000 rpm (continuously controllable)
    

    

      
Drive motor rating
      
~113 kW, 3-phase AC, 415 V
    

    

      
Motor nominal speed
      
~2900 rpm (up to approx. 5000 rpm)
    

    

      
Speed control
      
Vector control drive with encoder feedback
    

    

      
Gearbox type
      
Two-stage, single-helical, parallel shaft
    

    

      
Gearbox ratio
      
Approx. 14 : 1
    

    

      
Gearbox input speed (max)
      
5000 rpm
    

    

      
Gearbox output speed (max)
      
70,000 rpm
    

    

      
Gearbox design standard
      
AGMA 6011 I-03
    

    

      
Gearbox bearings
      
Hydrodynamic journal bearings with steel backing & white-metal lining
    

    

      
Radial load capacity
      
Up to ~25 kN (≈2.5 tonnes), via pneumatic bellow + load cell
    

    

      
Axial load capacity
      
Up to ~2.5 kN, via compact pneumatic cylinders + load cells
    

    

      
Radial load actuation
      
Pneumatic single-convoluted air bellow with E/P regulator
    

    

      
Axial load actuation
      
Multiple compact pneumatic cylinders with E/P regulator
    

    

      
Bearing lubrication oil temp
      
Approx. 35 °C to 200 °C (settable)
    

    

      
Bearing lubrication flow
      
Adjustable via proportional flow control valve (L/min range as specified)
    

    

      
Gearbox lubrication
      
Separate power pack with pump, filtration and cooling
    

    

      
Torque measurement range
      
Approx. 0–50 N·m, non-contact torque sensor
    

    

      
Speed measurement range
      
0–80,000 rpm (sensor capability)
    

    

      
Measured variables
      
Torque, speed, radial load, axial load, oil pressure, oil temperature, flow
    

    

      
Base structure
      
Cast-iron bed for high stiffness and vibration damping
    

    

      
Data acquisition
      
PC/IPC-based DAQ with multi-channel analogue and digital inputs
    

    

      
Data logging
      
Continuous logging with time stamping and test identification
    

    

      
Power supply (main)
      
415 V, 3-phase for drive & pumps
    

    

      
Auxiliary power
      
230 V AC single-phase for controls, auxiliaries, indicators
    

    

      
Pneumatic supply
      
Clean, dry compressed air (pressure as per actuator requirements)
    
  


Safety & Operating Philosophy
Due to the high speeds and stored energy, the rig is designed with a multi-layer safety concept:
• Mechanical guarding around all rotating components and moving parts
• Emergency stop circuits:
  ▹ Drive E-stop to cut motor power and decelerate the system
  ▹ System E-stop to safely shut down lubrication and auxiliary systems if necessary

• Interlocks to prevent test start if:
  ▹ Lubrication pressure or flow is insufficient
  ▹ Oil temperatures are outside acceptable ranges
  ▹ Pneumatic pressure for loading is not available
  ▹ Any critical alarm is active

Operating procedures require:
• Starting and stabilising lubrication systems before applying speed/load
• Observing defined warm-up times
• Avoiding any manual intervention while the test is running or components are rotating
The overall principle is that no high-speed operation is possible unless lubrication, loading and safety conditions are confirmed as healthy.

Key Benefits
From the user’s perspective, the High Speed Bearing Endurance Test Rig delivers:
• Realistic, high-fidelity endurance data under combined speed, load and temperature conditions
• Strong repeatability, driven by a rigid mechanical structure and precise control of lubrication and loads
• Deep insight into bearing behaviour, enabling better design choices and supplier management
• Comprehensive digital records that support qualification, certification and troubleshooting
• Flexibility to adapt to different bearing sizes, load levels and test concepts