Study On Mechanism And Experimental Study On Cooling And Lubrication Characteristics Of Ball Screw

With the development of high-speed cutting technology, ball screw pair is one of the key rolling parts of CNC machine. But high speed ball screw pairs are facing problems such as noise, vibration and temperature rise caused by friction. This research focus on the lubricating mechanism of ball screw pair and the factors influencing the temperature rise and thermal deformation; the corresponding tests are carried out.The result provides theoretical and experimental basis for the reasonable lubrication and cooling of the ball screw pair.First, based on the theory of elastohydrodynamic lubrication analysis and the lubrication state of the ball screw mechanism, combining with the ball screw pair structure characteristics and Hamrock - Dowson minimum oil film thickness formula, analysed the effect of different screw structure parameters different speed, different load, and different lubricating oil viscosity on the minimum oil film thickness by numerical calculation methodSecondly, the main heat source distribution and the heat conduction of the ball screw pair feeding system are analyzed, and the specific factors that affect the temperature rise are obtained. A hollow ball screw mathematical model of temperature field and thermal balance analysis is established, and the influence of the ball screw pair’s rotational speed, cooling capacity and heat transfer coefficient on the temperature rise was analyzed the influence of thermal expansion coefficient on thermal displacement of lead screw was analyzed.Then, according to the test requirements, determined the overall design of the test station, including mechanical design and test system design. By designing calculation program, determined the mechanical structure and 3D modeling test bench; described the structure and function of the test system, the selection of the PLC; according to the testing requirements, selected a sensor and introduced the sensor performance; according to the test result demand, designed a PC monitor screen.Last, in the cooling test, the temperature rise and noise contrast test of ball screw pairs under different speed, different load, different lubricating oil and different cooling conditions were provided by the test bench test. In the lubrication test, in order to provide the test basis for the reasonable lubrication of the ball screw pair, the test of the best lubricating quantity selection, the choice test of the best lubricating grease and the best lubrication time interval test were carried out.