For sliding friction pairs formed by differential gears and gaskets, it is necessary to study the friction performance under the coupling of multiple working conditions (impact, vibration and alternating load). For example, it is of great significance to study the performance of sliding friction pair in the rear axle differential of truck and the friction and wear performance of the internal parts of aircraft and ships under the coupling condition of multiple working conditions, so as to obtain longer service life and excellent performance by improving the friction performance. The ball-disc pairs were experimentally built to simulate the friction and wear mechanism of materials under different types of dynamic loads. Under the condition of non-polluting white oil lubrication, increased the contact ratio of the pair, and made the pair reach the experimental state of no dynamic pressure lubrication, selected different types of dynamic loads (step load, damped harmonic excitation load (DHE), Short-term high load) loading method. During the experiment, force sensors and online visual ferromagnetic sensors were used to monitor friction and wear rate signals in real time, and TR200 profilometer and scanning electron microscope were used to observe and study friction characteristics. The results show that a reasonable step load can improve the friction and wear state of the ball-disk pair during the running-in period and reduce the peak wear of the surface contact portion of the pair of materials. The main wear form of the experimental pair under constant load and step load for plastic flow and squeezing deformation, the fatigue of the surface material is caused by the high frequency fluctuating load of DHE. Therefore, it is concluded that the step load has an effect on improving the friction and wear performance of the mating pair, and the DHE load has a damage effect on the mating pair.

For complex curved di cult to machine parts, a new method based on pneumatic suspension abrasive pool bright nishing processing is proposed, using the mixing of pneumatic suspension abrasive, the workpiece surface and uidized abrasive to produce relative motion velocity, so that the solid particles and workpiece surface microscopic two-body abrasive wear to achieve the effect of precision machining. The experimental test material is the widely used Q235 steel plate. The experimental parameters include workpiece shape (round tube, square tube, cylindrical), abrasive particle size (24, 80, 120 mesh count), gas-solid two-phase ow pattern (dispersion uidization state, turbulent uidization state, spurting uidization state), abrasive particle shape (sphere, irregularity) and spindle speed (600, 900, 1200 rpm). An orthogonal test was designed according to the experimental parameters, and the degree of in uence of each parameter on the processing of the abrasive cell was evaluated by the roughness of the workpiece surface together with the scanning electron microscope (SEM) micrograph of the workpiece surface, and the optimal combination of parameters was judged using the extreme difference method as well as the factor trend diagram. The results show that under the present experimental conditions, the workpiece surface roughness (Ra) can reach a minimum value of 0.4 µm. The feasibility of gas-solid two-phase ow processing is demonstrated from an experimental point of view, and the advantages of abrasive cell processing are explored.

For complex curved difficult to machine parts, a new method based on pneumatic suspension abrasive pool bright finishing processing is proposed, using the mixing of pneumatic suspension abrasive, the workpiece surface and fluidized abrasive to produce relative motion velocity, so that the solid particles and workpiece surface microscopic two-body abrasive wear to achieve the effect of precision machining. The experimental test material is the widely used Q235 steel plate. The experimental parameters include workpiece shape (round tube, square tube, cylindrical), abrasive particle size (24, 80, 120 mesh count), gas-solid two-phase flow pattern (dispersion fluidization state, turbulent fluidization state, spurting fluidization state), abrasive particle shape (sphere, irregularity) and spindle speed (600, 900, 1200 rpm). An orthogonal test was designed according to the experimental parameters, and the degree of influence of each parameter on the processing of the abrasive cell was evaluated by the roughness of the workpiece surface together with the scanning electron microscope (SEM) micrograph of the workpiece surface, and the optimal combination of parameters was judged using the extreme difference method as well as the factor trend diagram. The results show that under the present experimental conditions, the workpiece surface roughness (Ra) can reach a minimum value of 0.4 µm. The feasibility of gas-solid two-phase flow processing is demonstrated from an experimental point of view, and the advantages of abrasive cell processing are explored.