Reduction gearbox

Fig. 2.9 Free-body diagrams for reduction gearbox. Gearbox parameters...

The foundations of any turbogenerator installation play a significant part in the safe operation of the machine. Industrial turbines will normally operate at above synchronous speed and will drive an alternator via a reduction gearbox. Any vibration or out of balance occurring under both normal or abnormal operation must be accommodated by the foundations, and their design should therefore best be undertaken by a specialist organization. The layout... 

Air cooler fans are normally 14 to 16 ft in diameter. Fan motors are almost always electric, although a few hydraulic and gasoline engines have been used. Fan tip speeds are normally 12,000 ft/min or less. In order to produce this speed, U.S. practice is to use V-belt drives or reduction gearboxes. V-belt drives up to about 30 hp are used, and gear drives at a higher motor horsepower. Single fan motors are usually limited to 50 hp. 

Below, some engineering features including are highlighted and briefly summarized. Beyond the benefit obtained by the fact of using a frequency converter solution instead of the original solution (based on two rotor-wound induction motors with external resistances and reduction gearbox) in terms of energy efficiency, other specific benefits are obtained ... 

Figure 25. Refurbished main reduction gearbox ready for dispatch...

The study is illustrated by reference to a train of gears used in a business machine. The development history of this reduction gearbox is followed, and its production process is outlined. 

Fig. 4.1 Diagrammatic representation of the reduction gearbox used in the office-copier...

This type of coupling effect is common in single-reduction/increase gearboxes or other machine-train components where multiple running or rotational speeds are relatively close together or even integer multiples of one another. It is more destructive than other forms of coupling in that it coincides with real vibration components and tends to amplify any defects within the machine-train. 

Figure 1.2 Schematic of a typical plasticating single-screw extruder. The extruder is equipped with four barrel heating and cooling zones and a combination belt sheave gearbox speed reduction drivetrain (courtesy of William Kramer of American Kuhne)...

The availability of power and torque to the shank of the screw is extremely important to the success of an extrusion process, especially if modifications to the line are planned to increase the rate. That is, the proper level of power must be available at the proper screw speed. Thus, the motor size and speed, belt sheaving if used, and gearbox reduction must be specified to provide enough power to the screw to plasticate and pump the resin at a high rate. 

Pf pressure at the tip of the screw for an injection-molding plasticator (Eq. 10.22) Q extrusion rate in kg/h O specific rate in kg/(h-rpm) for Eq. 10.21 R compression rate in the helical direction Pjs belt sheave reduction Rg speed reduction for the gearbox S support distance from the fixed end of the barrel shear strength of the material used for the screw t plasticating time in seconds (Eq. 10.21)... 

Lead length, flight width, and flight clearance were 203.2, 20, and 0.20 mm, respectively, in all sections of the screw. A 38 mm diameter screw cooling hole was drilled in the shank end of the screw, and it extended 4 diameters into the feed section. The first 2.5 diameters of the screw were inside a water-cooled smooth-bore feed casing. The motor was 450 kW and had a base speed of 1750 rpm. The gearbox reduction was 17.33 1 for a maximum screw speed of 101 rpm at the base motor speed. The motor could be field weakened to provide higher screw speeds. 

In order to provide a higher torque to the screw, a belt sheave system was installed between the motor and the gearbox. This sheave system had a reduction ratio of 1.95, reducing the maximum screw speed from 125 to 65 rpm. Sheaving... 

A typical layout of a palm oil mill is shown in Figure 7 where the main stations of the process are also indicated. The equipment selected has to be carried out with care in order to obtain the correct balance for throughput, steam consumption, energy demands, and economics of the supply of stand-by equipment. Standardization of equipment is an important point to consider when selecting machinery on the basis of within mill and between mills when applicable. When a set range and/or make of equipment can be chosen (e.g., valves, gearboxes, electric motors and starts, etc.), considerable benefits can accrue by way of a reduction in the amount of spare parts to be carried. 

The use of aluminum in the automobile industry is steadily increasing. The replacement of steel permits a decrease in fuel consumption of the vehicles due to weight reduction. In the car industry, aluminum is mainly used in body parts, starters, generators, compressors, admission pipes, oil vats, gearbox housings, cylinder heads, and even engine blocks. 

The experimental setup is shown in Fig. 1. It consists of the following items (1) an AC drive with a nominal speed of 1760rpm (2) a gearbox with a reduction ratio 3.53 1 yielding a rotating speed of 500 rpm (3) a torquemeter with a measurement range between 0 and 22.6 Nm (accuracy of 0.1% at full scale) and (4) a transparent vessel with a hemispherical bottom. 

Due to the reduction ratio between gear (3) and one of the large coupling gears (2), the reduction ratio of the gearbox (4) can be kept small. Consequently,... 

Figure 274(c) shows a drive train that is applied for contemporary medium and large scale roller presses. It employs a double output-shaft gear reducer (2/4) powered by a motor (5) by way of a torque-limiting clutch. The completely enclosed, dust-tight gearbox provides the necessary reduction in speed and the distribution of power to the two roll drive shafts (3). Precision gear-tooth... 

The most important part of the transmission is the main gearbox, which contains the most heavily loaded reduction gears transmitting power to the main rotor blades. It is always oil lubricated but a variety of different oils are used in different helicopters. 

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