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1 Mathematical model This paper mainly considers the influence of the impact load of the gear on the elastohydrodynamic lubrication of the gear, and the initial load of w0 in the impact load wi=w0e-0.2tsin(Ï€tÎ 4);
t time variable.
The mathematical model of the line contact thermoelastic problem includes the general Reynolds total relief valve 1 for pressure overload protection.
(4) DOSCO's idea of ​​designing and supporting the rear support device is to raise the unit and provide sufficient space for inspection and inspection of the lower part of the roadheader. In the process of cutting operations, the rock is often hardened. In order to reduce the vibration of the unit and increase its stability, it is also necessary to put down the shovel and the rear support device. Once the driver forgets to retract the support cylinder after the driver has neglected, he will move the engine group. This can cause great damage to the rear support cylinder.
Optimization scheme: design and install 2 or so rear support cylinder shrinkage limit reversing valves on the rear support device (this reversing valve is connected in series to the inlet and return lines of the left and right travel motors), through the touch plate and reversing The valve hydraulically interlocks the rear support cylinder and the travel motor to ensure that the oil passage of the travel motor can be turned on to achieve unit travel only when the rear support cylinder is in a certain position, thereby avoiding accidental mechanical damage.
3 Conclusion For foreign advanced technology and equipment, while insisting on bold “introduction and absorptionâ€, it is necessary to “strictly manage and reform and innovateâ€.
Through engineering practice verification, from the design to the daily use and maintenance of the hydraulic system of the MK3 rock roadheader, paying attention to the above problems, it can ensure safe and reliable operation to a large extent, and play out within a certain range. The greatest performance.
Equation, Roelands viscosity-viscosity temperature equation, density equation, load balance equation, film thickness equation and oil film and two solid energy equations, see the literature [1, 2]. The current design of gear lubrication problems, most of which are applications Assume that the lubricant is the result of a study of the ideal Newtonian fluid. In fact, the fluid used as a gear lubricant is not strictly in accordance with New2ton's viscous shear law and therefore does not belong to Newtonian fluid. This paper uses the Ree-Eyring fluid model. Solve iteration between pressure and temperature. The pressure solution uses the multigrid method, in which the elastic deformation is solved by the multigrid integration method.
2 Results and analysis is the waveform diagram of the impact load and the friction coefficient after considering the impact load, the center pressure and the central film thickness compared with the case without the impact load, S is the distance of the meshing point from the node. The waveform of the impact load, because the impact load is only applied during the initial period of the meshing, as the amplitude of the impact load decreases, it only affects the above parameters during the initial period of meshing, in the subsequent meshing time. There is no effect on these parameters. (b) is a comparison of the friction coefficient. At the maximum impact load, the friction coefficient is three times that without the impact load; the minimum impact load reduces the pressure on the gear, and the friction coefficient can even reach 0. In (c) and 1(d), the central film thickness is reduced by 1 μm under the maximum impact load, the center pressure is increased by 013 GPa under the maximum impact load, and 014 GPa is reduced under the minimum impact load, so this energy increase The impact load of a large load is unfavorable for lubrication.
Comparison of friction coefficient, central film thickness and center pressure when there is impact load and no impact load Consider the impact load at the point of engagement, the initial moment of single tooth engagement, the initial point of joint, double tooth engagement, and the point of engagement. A comparison of oil film pressure and oil film thickness with no impact load at different meshing moments, it can be seen from the figure that only the pressure of the oil film and the thickness of the oil film are affected by the impact load at the time of the biting, and there is no change at other times. At the point of entry, due to the presence of the impact load, the Hertz contact area at this time is widened, the pressure is increased, and the film thickness is thinned.
The pressure and film thickness of different meshing points when there is impact load and no impact load 3 The impact load of the knot at the initial stage has a great influence on the oil film pressure and film thickness at the initial stage. There is little impact on the other moments of the meshing process. The minimum film thickness and the maximum pressure occur at the maximum peak load moment of the impact load, so the biting impact of the gear is unfavorable to the lubrication state of the gear. This conclusion has important practical significance for guiding the lubrication design and anti-fatigue design of gear transmission, preventing gear lubrication failure and fatigue failure.
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Below image as a reference:
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