GB/T 46635.1-2025Plain bearings - Automotive engine bearing test rig using actual connecting rods - Part 1: Test rig (English PDF)

5.1 Test Rig Structure

Figure 1 shows a schematic diagram of the bearing test rig structure.

Explanation of indexing numbers.

1 -- Test shaft;

2 -- Test connecting rod;

3 -- Support bearing housing;

4 -- Oil supply system;

5 -- Force sensor;

6 -- Dynamic servo actuator;

7 -- Torque sensor;

8 -- Gearbox;

9 -- Torque-limiting clutch;

10 -- Drive motor;

11 -- Flexible coupling.

Figure 1 -- Schematic Diagram of the Bearing Test Rig Structure

The specific test rig meeting the requirements of the scope is described below.

An actual connecting rod is used to simulate operating conditions within the engine. The test bearing is mounted on the big or small end of the connecting rod, and a dynamic load is applied.

Figure 1 illustrates the overall structure of the test rig. The test bearing, housed within the test connecting rod (2), is mounted on the test shaft (1); this shaft is driven by a drive motor (10) via a torque sensor (7) and a torque-limiting clutch (9). Friction in the test bearing is measured using the torque sensor, and an emergency stop device protects the test rig from damage caused by bearing failure. The dynamic servo actuator (6) is capable of generating dynamic loads at frequencies higher than the engine speed. The oil supply system (4) supplies oil to the test bearing within the test connecting rod (2), simulating the oil supply delivered through an engine crankshaft. The dynamic load mode is synchronized with the shaft oil hole position. The measurement of the bearing’s stable temperature is shown in Figure 7; contact between the thermocouple and the back of the bearing shell is maintained by applying constant pressure to the thermocouple.

The measurement of the test bearing’s stable temperature is shown in Figure 7; contact between the thermocouple and the bearing backing is maintained by applying constant pressure to the thermocouple. Figure 8 illustrates that the test rig is capable of measuring the effect of axial misalignment on bearing backing temperature.

The dimensions and stiffness of the test connecting rod assembly can be freely selected within appropriate ranges. Other dynamic load parameters that can be freely selected within appropriate ranges include waveform, amplitude, frequency, and load step size. Examples of variables related to bearing performance during testing include temperature, bearing hardness, polishing methods, bearing geometry (roundness, roughness, waviness, concavity, and straightness), lubricant viscosity, and additives. These variables can be specified within appropriate ranges, allowing for the simultaneous testing of multiple bearing performance characteristics.

5.2 Test Rig Frame Structure

When testing bearings under dynamic loads, it is crucial to avoid resonance in the test rig frame.

The resonant frequency of the test rig frame shall be higher than the frequency of the dynamic load. Examples of calculated resonant frequencies based on frame type are provided in

Appendix D.

5.3 Foundation Structure

To ensure the reliability of the test, the structure and mass of the test rig foundation must be considered.

Figure 2 illustrates two types of foundation structures for the test rig.

8 -- Equipment mounting surface;

9 -- Concrete sand barrier.

Figure 2 -- Examples of Test Rig Foundations

In Figure 2a), isolation filler (3) is packed around the panel (1) and the concrete (6) to decouple floor vibrations. In Figure 2b), the panel (1) is supported by vibration-damping springs (2), which isolate vibrations. Generally, the configuration in Figure 2b) offers superior vibration isolation, whereas the configuration in Figure 2a) allows for lower costs.

In Figure 2a), the foundation mass is the combined mass of (1), (6), and (7). In Figure 2b), it is the mass of (1) alone. For both structures, the foundation mass should ideally be 10 to 20 times greater than the maximum vibration load, calculated as the product of the maximum acceleration and the accelerated mass.

5.4 Testing Using An Actual Engine Connecting Rod

5.4.1 Structure around the test bearing

Figure 3 illustrates the structure of the test rig’s main components, including the test bearing and the test shaft.

As described in Clause 4 and shown in Figure 3, the test bearing (1) located in the connecting rod (2) is mounted on a rotating test shaft (3) supported by support bearings (8) and bearing housings (7). Lubricating oil is supplied to the test bearing (1) via the oil supply unit (4) and the oil supply hole (6), simulating an actual crankshaft.

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