Simulation And Experimental Study On Churning Loss Of Gearbox

Automobile gearbox is the main component of energy consumption of automobile transmission system,and its transmission efficiency occupies an important place in the whole vehicle.It is of great significance to improve the service life and energy utilization rate of gearbox by reducing the power loss of gearbox and optimizing the transmission structure of gearbox.It is found that the gear churning loss accounts for a large proportion in the loss of gearbox.However,the research on the gear churning loss mostly focuses on the aspects of speed,gear and lubricating oil parameters and temperature.The box geometry is also an important factor,but there are few studies on the relationship between this factor and the gear churning loss.In this paper,adopting the research method combined the MPS fluid simulation and experimental,Different fluid models were built and gear churning experimental equipment was set up with the geometric structure of the box,gear speed,steering,immersion depth as the main research parameters.Then Simulation and experimental analysis are carried out on the gear churning model affected by different factors.Specific research contents are as follows:(1)The experimental study of gear churning based on the box structure is summarized,and the box geometry is determined as one of the key factors affecting the gear churning loss and the research direction of this paper.A solid-liquid coupling model of MPS gear pair churning was established based on the gear thickness as a variable.The results of torque loss and the distribution of lubricating oil flow pattern and velocity were obtained and it is verified by experiments.The results show that the velocity vector distribution of MPS fluid simulation basically conforms to the fluid continuity hypothesis,and the lubricating oil distribution of simulation and experiment are basically consistent,and the churning loss error between the two is less than 9%,thus verifying the reliability of MPS method.It is also shown that the churning loss increases with the increase of the thickness of the gear.(2)The gear pair churning models with different fillers and different space sizes of reducer were established,and the lubricating oil flow pattern and velocity distribution of the gear churning under different MPS model conditions at the same speed were analyzed.The churning loss data graph was drawn based on the simulation results.The results show that the partition can inhibit the fluctuation of the lubricating oil,and reduces the torque loss by reducing the lubricating oil flow stirred by the gear.Because of the number and location of the vertical partition,the result is not the same.As for the influence of the distance between the box wall and the gear,that the closer the box wall is to the gear in axial and radial direction leads to smaller gear churning torque loss.(3)Establishing the three dimensional model of the experimental device,drawing and processing the parts,selecting the model of electrical components,designing the data acquisition system and circuit,On this basis,a gear churning loss experimental device was built.Secondly,according to the experimental method and purpose,the influence law of gear steering,immersion height,diaphragm and vertical partitions on the gear churning loss is tested under different rotating speeds.Through analysis of the experimental data,it is concluded that with the increase of the speed,the gear churning loss increases continuously,which basically conforms to the linear relationship.The churning loss of gear increases with the increase of immersion depth.When other factors remain unchanged,the churning loss of the diaphragm model is lower than that of the non-diaphragm model.However,with other conditions unchanged and the same diaphragm model,the churning loss of counterclockwise steering is lower than that of clockwise steering.When other factors remain unchanged,the churning loss of the single pair vertical partitions model does not change significantly compared with that of the model without partitions.The gear churning loss of the two-pair vertical partitions model is lower than that of the no-partitions model.