Installation and Maintenance

General

The Radicon speed reducer is a precision product incorporating the very best in worm gear design. It is a self- contained unit of simple rigid construction involving in the minimum number of moving parts and embodying a lubrication system which ensures a positive supply of oil to gears and bearings at all running speeds. With careful installations Radicons will give complete reliability in service and the o­nly attention necessary is an occasional oil level check. This publication gives information o­n correct installation, thus ensuring that the high initial efficiency is unimpaired in operation.

Installation

It is preferable, although not essential, to mount the gear unit and prime mover o­n a common bedplate. Any foundation used should be rigid so as to minimize the effect of fluctuating or heavy loads. When lowering a bedplate o­n to its foundation flat steel packing should be used, placed o­n both side and as close as possible to each foundation bolt. Packing should also be placed in such a position that support is given in the plane of the coupling faces. Care must be taken so as not to spring the bedplate when the final bolting down is carried out after the unit and prime mover have been lined up, as strains maybe set up in the gear casing and errors of alignment in shafts and gears may be introduced. It is advisable to check the alignment after bolting down, even when a gear until and motor have been assembled and lined up o­n a bedplate.

After installation and lining up has taken place, the two opposite feet should be drilled, reamed and dowels fitted.

Allowance doe bearing clearance

Where a radicon speed reducer with shafts mounted o­n ball or roller bearings, is coupled to a prime mover or a driven machine with plain bearings, an allowance for “lift” should be made to accommodate the probable change in centre height when running, due to thickness of the oil film and upward reaction (if any) under load.

No hard and fast rule can be given to the exact amount of correction to allow and this, dependent upon so many factors peculiar to individual cases, is largely a matter of experience.

Effects of Temperature

Any change is temperature will alter the height of a shift above its foundations. If there is much difference between the temperature of a gear casing and that of the driven machine, or prime mover, the resulting difference in level may be appreciable. The coefficient of linear expansion of cast iron is 0.000006 inch per inch per deg Fahrenheit: hence with a centre height of 20 in. Above the bedplate and difference in temperature of 50deg F between the gear casing and the machine, the error of alignment, if correct when cold, will be 0.006 in.

Such conditions may, particularly in the case of large units and those which are close- coupled, impose very severe loads o­n the bearings. If this is so, it is recommended that an allowance be made so that the alignment will be more nearly correct under normal working conditions.

Coupling

The use of flexible couplings is recommended for all units o­n driving and driven shafts as they permit limited errors of alignment. David brown “cone ring” flexible couplings are particularly suitable and economical type, being designed to accommodate small alignment errors normally met in practice. Excessive errors should be eliminated to prevent unnecessary wear o­n the rubber bushes. This type of coupling is available in a comprehensive series of standard sizes and is suitable for all applications within the range.

The “cone ring” coupling is, as its name suggests, of the pin and bush type, each bush consisting of a series of conical rubber rings permitting slight errors of alignment without affecting the efficiency. For further details of David brown “cone ring” couplings see publication DBG/ 106.

Lining up

Errors of alignment fall into the categories of angularity (Fig.1) and eccentricity (Fig. 2), or combinations of both. Angularity error should be corrected first by using feeler gauges (Fig. 3) and arriving at a constant measured every 90deg of rotation, rotation both halves simultaneously.

Eccentricity error can be corrected by using a straight edge (Fig. 4) if both couplings have the same outside diameter. If not a straight edge should be used in conjunction with a feeler gauge equal to half the difference in diameters. Here also checking should be done every 90deg while rotating both halves simultaneously.

Changing Handing

When changing the handing of the slow speed shaft extension, the shaft complete with worm wheel, 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 handing 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 worm wheel 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 affected by means of the shims between end covers and bearing housing which should be moved from o­ne side to the other. It is essential that the top of the gear case be replaced in its original position.

The contact marking is checked by painting the worm with red lead or Prussian blue and rotating the worm by hand while applying a small braking pressure to the wheel, also 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. This arrangement is shown in the diagrams. When the correct wheel setting had been reached o­n the U type speed reducers, the oil scraper clearance relative to the worm wheel should be set at 0.010 in. to 0.015in.

Axial Floats

After re-handling it is essential that shaft end floats be correctly set. The following axial floats for worm shaft and wheel shaft are recommended. They should be checked preferable using a dial indicator gauge mounted o­n a magnetic base.

Lubrication

The radicon 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, oil filler ***** ventilator and drain plugs.

Radicon filler are supplied without oil and must be filled with the correct grade of lubricant to the correct level. It is important to ensure at the correct oil level is not exceeded as over filling causes oil churning with resulting overheating and leakage.

Maintenance

(1)Weekly inspection

(a) Check the oil level by means of the dipstick or oil plug and if necessary, top up with the recommended grade of lubricant.

(b) Ensure that breathers are clean and operating properly. Care must be taken not to paint over breathers; otherwise pressure will build up, resulting in oil leakage.

(c) On units having grease lubricated bearings, add two shots of grease from a grease gun, or where screw-in type lubricators are fitted, screw in the lubricator two turns are refill when necessary with the recommended grease.

(2) Oil changes

Regular oil changes are essential to ensure that the unit gives long and trouble – free service. The frequency at which the oil should be changed is determined by the following factors:

(a) Oil temperature – unit operating under load

(b) Type of oil – plain or containing additives

(c) Environment - humidity, duct etc

(d) Operating conditions – shock loading etc