Determination of Optimum Working Parameters for Multiple Response Characteristics of Worm Gear Box

Abstract

The reason for this task is to optimize the multiple response of single start worm gear using three working parameters to improve its performance. As the input torque and lubricant heating time are the most effective responses of worm gear box to reduce the no-load dependent losses, they are taken as the response parameters in this research. Taguchi Grey Relational Analysis (GRA) is the method used to determine the influence of type of lubricant, volume of lubricant and speed of worm gear on multiple responses (input torque & lubricant heating time) of worm gear. The specific test rig is developed based on direct torque measurement technique to measure the input torque and lubricant heating time of worm gear box. Experimental results have shown that the input torque and lubricant heating time can be improved effectively through Taguchi-Grey Relational Analysis. The result is validated using the Confirmation Test. ANOVA determines the important of parameters. It has been found that the type of lubricant and speed of worm gear are influential parameters for worm gear performance. By selecting these parameters, efficiency of the worm gearbox can be increased.

Comparative Investigation of Worm Positions for Worm Gear-box Performance under No-Load Condition

“…The test matrix is given in Table 1. The speed of the driving shaft was selected as 1000 rpm minimum speed and 1400 rpm maximum speed [18]. Static oil levels were selected based on the capacity of the gearbox and worm gear manufacturer report [19].…”

“…The gearbox was operated at various lubricant volumes which are shown in Figure 4. The experiments were tested at three temperature levels of 30 ºC, 40 ºC and 50 ºC [18]. When worm gear operated at a 1.5-liter volume only the worm is fully immersed in lubricant and it operated at 2.7-liter volume both worm shaft and worm wheel are almost immersed in lubricant for worm at the bottom position as shown in Figure 4(b).…”

“…At 1.5-liter volume, there is no dragging of lubricant for worm at the top position therefore the input torque was very small. For the worm shaft at the bottom position at 1.5liter volume, the worm shaft was fully immersed so there is dragging of lubricant therefore comparatively large input torque was noted [18]. Once the volume of lubricant increased to the next level, dragging of lubricant faced by the worm shaft at the top position so the gap in input torque between both positions was reduced.…”

“…As temperature increases viscosity of lubricant goes down, this reduces the dragging force of lubricant [14]. Due to static head, dragging forces are high for worm shaft at the bottom and less for worm at the top so input torque for worm at top position is less for every temperature condition [18]. Input torque required for the bottom position of the worm shaft reduces as temperature increases, however, the gap was remained almost the same for temperature range from 30 ºC to 50 ºC.…”

“…Lubricant is not essential only for the friction of gear and bearing but it is also useful to dissipate the heat during the operating condition [18]. Figure 8(a) shows the heating rate of lubricant for both operating conditions at volume 2.1 liter and speed of worm 1000 rpm.…”