| Under the background of the increasingly perfect intelligent manufacturing technology and intelligent manufacturing system,the development of industrial robots is changing into each passing day.The high-precision robot reducer has also received more and more attention,among which the RV reducer has been widely used in the field of robots by virtue of its compact structure and large deceleration ratio.The friction between gear transmission and rolling bearing at all levels of RV reducer will generate more heat of the working process.After being absorbed by the reducer,the transmission mechanism will warm up and expand on deformation,reducing the relative motion accuracy between parts.In severe cases,the adhesive failure may be caused,the lubrication effect will be affected,the wear will be accelerated,and the service life of the reducer will be reduced.Therefore,it is necessary to analyze the temperature field distribution of RV reducer.The friction heat distribution of the tooth surface of the gear drive including planetary gear drives and cycloidal pinwheel drive and the heat transfer coefficient of the two gears were calculated theoretically.The steady-state temperature fields and transient temperature field of gear transmission were calculated by finite element method.It was found that the steady-state temperature and meshing heating rate of cycloidal pin wheel transmission were higher than that of planetary gear transmission.On the basis of steady-state temperature production,the thermal-structural coupling calculation is carried out.The maximum thermal stress of gear parts is concentrated on the root position.The influence factors of tooth surface flashover temperature and tooth surface flashover temperature were analyzed.The load,friction coefficient and sliding speed were positively correlated with the flashover temperature.The heat value of cylindrical roller bearing and tapered roller bearing in RV reducer was compared and calculated by three different methods,and the heat transfer coefficient of the two kinds of rolling bearings was analyzed by comparison,and the steady-state temperature fields and heat-structure coupling field of the two kinds of rolling bearings were calculated by finite element analysis software.The results show that the friction heat and heat transfers coefficient of cylindrical roller bearings is higher than that of tapered roller bearings,and the steady-state temperature is slightly lower than that of tapered roller bearings,and the highest temperature of both types of bearings is located in the inner raceway of bearings.The temperature field of RV reducer was simulated.The highest temperature of the main transmission mechanism is the gear,and the bearing temperature is lower than that of the gear.The cycloidal gear,which is the key part with the highest temperature in RV reducer,was modified and cool.The optimal modification amount of different combination modification methods of the same radial clearance was calculated,and the friction heat distribution of tooth surface was compared and analyzed.It was found that the tooth profile modification had little effect on the peak value of instantaneous friction heat,but great effect on the peak position,and opposite effect on the periodic friction heat.On this basis,the steady-state temperature field of the gears before and after the modification was compared by finite element analysis,and the conclusion was drawn that the tooth profile modification could reduce the temperature.The best modification method of the cool effect was positive equidistance + positive shift distance modification.Taking RV-80E reducer as the experimental object,the rated speed was applied to it and the temperature was measured.The correctness and feasibility of temperature field calculation method and hypothermia of cycloidal gear modification were verified by experiments. |
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