Info

Cylindrical

Double-enveloping cone-drive gears

Finishing methods (singly or in combination)

Worm gears: hobbed, worm-milled, and ground

Worms: threads generated with cutter and finished by polishing. Gears: hobbed. Both members then lapped and matched together

Power range, hp (kW)

Up to 400 (300)

Fractional to 1,430 (1070) dependent on ratio, center distance, and speed

Speed range pitch line velocity, ft/min (m/min)

Up to 6000 (1830)

0 to 2400 rpm, or 2000 (610) rubbing speed with splash lubrication. Higher speeds permissible with special combinations.

Gear efficiency, %

From 25 to 95, depending on ratio

52 to 94, depending on ratio and speed

Quietness of operation

Relatively quiet operation up to 6000 ft/min (1830 m/min)

Smooth and quiet up to 2000 ft/min (610 m/min); can run quietly at higher speeds with special attention to lubrication, mounting, materials, balancing, and so on.

Load imposed on bearings

Radial and thrust

Radial and thrust

Gear tolerances are dependent on method of manufacture, application, load requirements, and speeds. For spur, helical, and herringbone gears, ANSI/AGMA Gear Classification Manual 2000 A-88 lists quality numbers from 3 to 15 for coarse-pitch gears and 5 to 16 for fine-pitch gears, quality increasing as quality number increases. The general range of quality for gears now being manufactured is from quality numbers 5 to 14. Quality numbers relate to runout, tooth-to-tooth, spacing, profile, total composite, and lead tolerances. Bevel and hypoid gear tolerances range from 3 to 13.

Gear tolerances are dependent on method of manufacture, application, load requirements, and speeds. For spur, helical, and herringbone gears, ANSI/AGMA Gear Classification Manual 2000 A-88 lists quality numbers from 3 to 15 for coarse-pitch gears and 5 to 16 for fine-pitch gears, quality increasing as quality number increases. The general range of quality for gears now being manufactured is from quality numbers 5 to 14. Quality numbers relate to runout, tooth-to-tooth, spacing, profile, total composite, and lead tolerances. Bevel and hypoid gear tolerances range from 3 to 13.

[C > SOLAR GEAR FIGURE 8 Single epicyclic gear drives

unit is transmitting its rated power because when no power is being transmitted through the reducer, all the input power (small as it may be) is used in friction and the efficiency is zero.

Ratios available in standard reducers and efficiencies to be expected when units are transmitting rated power are given in Table 1.

Epicyclic Gear Units Epicyclic gear units are sometimes used for pump drive applications. The important advantages are compact configuration, coaxial shafts, and light weight.

The most common types of epicyclic arrangements are planetary, star, and solar (Figure 8). The planetary configuration (with the planet carriers integral with the output shaft) is the most commonly used arrangement. It is simple and rugged and gives the maximum ratio for the size of gears. The star arrangement (where the planet carrier is fixed and the internal gear rotates integrally with the output shaft) is used for higher-speed applications because centrifugal loads of the planet gears are eliminated with nonrotating planet carrier. The solar arrangement (where the pinion is fixed and the planet carrier is integral with the output shaft) has the input through the internal gear. This arrangement gives epicyclic advantages but allows a low ratio, generally less than 2:1. Higher ratios (in the range of 8:1 to 60:1) can be obtained utilizing double-reduction or compound-planetary arrangements.

Renewable Energy 101

Renewable Energy 101

Renewable energy is energy that is generated from sunlight, rain, tides, geothermal heat and wind. These sources are naturally and constantly replenished, which is why they are deemed as renewable. The usage of renewable energy sources is very important when considering the sustainability of the existing energy usage of the world. While there is currently an abundance of non-renewable energy sources, such as nuclear fuels, these energy sources are depleting. In addition to being a non-renewable supply, the non-renewable energy sources release emissions into the air, which has an adverse effect on the environment.

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