Operational efficiency of worm gears varies from 50% to as high as 95%. A number of factors affect the efficacy, including ratio, the input speed, the geometry of the tooth and lubrication. By far the most important is the ratio. Higher helix angles mean less friction and thus push greater efficacy. In comparison, helical gears usually have a yield of 98% comb through. For example, a double-propeller reduction gear has a yield of about 0.98 3 0.98 = 96%. A lower unit ratio (5: 1, for example), a plurality of threads on the worm gear and a pitch angle is greater relative to a high ratio unit.
In addition to speed ratio, the most important factor that determines the effectiveness is the contact pattern between the worm gear and the clutch. Therefore, the fitter the contact patch must be manually measured by varying the positioning of the discs behind the front and rear bearings on the output shaft and gear set. This is time consuming and expensive, so most manufacturers use statistical analysis to predict the amount of Shim and location. Transmission inefficiency converts the energy into heat. AGMA (American Gear Manufacturers Association) Guidelines for worm gears, spur gears, and other types of gear to limit the maximum operating temperature of 100 ° C above the ambient, not more than 200 ° F to have to be much larger than the nominal equivalent remain spur within these guidelines to reduce worm or to auxiliary cooling means (for more heat to dissipate).This is a contact pattern relative usually centered. The preparation of the gearbox housing and Worm drive gear sub-assemblies creates a stack of tolerances so that the position of the center line of the gear teeth cannot be accurately predicted.
A computer records the data and calculates the thickness and the position of the wheels in exactly the gear in the worm shaft center, and ensures the axial clearance in accordance with the exit tapered roller bearings at the same time. This maximizes operational efficiency and reduces the temperature rise. To eliminate inconsistencies ground contact, EFA developed an automatic centering machine which accurately measures each screw and gear subset and the gear housing and bearing cap.
Machine centering is part of the screw conveyor. The operator loads the transmission case cover and the bearing, and the machine determines the distance between the output bearing seats.
The computer then compares the level of the output stack subassembly to the distance between the bearing housing seats and calculates the required compensation module for the axial clearance desired bearing. The middle worm displays it as assemblers distribute washers between the front and rear bearing for the speed in the case to be centered exactly. The measurement accuracy is ± 0.001. Total cycle time, with the exception of loading and unloading in less than 20 sec.
The part of output, that includes the worm gear screw and bearing shells and taper, loads on a separate station for two simultaneous measurements. The device applies a predetermined load, the opposite bearing shells, and the amount of the total stack is measured. At the same time a master worm is engaged and swinging the output speed of worm, the exact center of curvature of the gear teeth to find. The machine then measures the distance between the center line and the rear bearing shell.