Gear boxes are to be rigidly mounted so as to minimise the effect of fluctuating or heavy loads. Always check the alignment after bolting down. After installation and alignment has taken place, properly locate the gear unit by means of dowels at appropriate locations preferably in diagonal direction.
The use of flexible couplings (Love joy / Gear coupling flanges with rubber bushes/tyre couplings) are very important for the improved performance of the gearbox. The couplings are to be lined up to avoid the misalignment of angularity and eccentricity.
When changing the handing of the slow shaft extension, the shaft complete with wormwheel, bearings, etc. should be reversed as a unit. It should be appreciated that this has the effect of reversing the offset of the wheel relative to the worm. When changing the slow speed shaft handling of V type units, it should be noted that the position of the wheel relative to the case must not be changed; it is necessary therefore to press the wheel from the shaft. The position of the shaft in relation to the wormwheel must be reversed. The end covers should be located in their respective positions.
It is necessary to check contact markings on the worm wheel teeth and if any axial adjustment of the worm wheel is necessary, it can be effected by means of the shims between covers and bearing housing which should be moved from one side to the other. It is essential that the top half of the gear case be replaced in its original position (Not applicable for Adaptables).
The contact marking is checked by painting the worm with red lead or Prussion Blue and rotating the worm by hand while applying a small breaking pressure to the wheel by hand.
The correct marking should be slightly heavier on the “leaving side” of the teeth, relative to the direction of rotation of the worm, so as to provide “lead in” for the lubricant and to avoid concentration of pressure on the entering side as this would affect the smoothness of operation.
After re-handing it is essential that shaft end floats be correctly set. The following axial floats for wormshaft and wheelshaft are recommended. They should be checked preferably using a dial indicator gauge mounted on a magnetic base.
The MM Speed Reducer lubrication system is self contained positive and automatic at all speeds of operation and in either direction of rotation. Adaptable units are provided with breather, oil level and drain plugs and it must be ensured that these are correctly positioned as shown on the accompanying diagram. Other units incorporate a dipstick for oil level checking, an oil filler-cum-ventilator and drain plugs. Their locations are shown below.
MM Speed Reducer units are supplied without oil and must be filled with the correct grade of lubricant to the correct level. It is important to ensure that the correct oil level is not exceeded as over filling causes oil churning which resulting in overheating and leakage.