• Gearbox Service Kit
• Gearbox Service Factor Calculation

Sizing a gearbox (or gearmotor) for an industrial application typically begins with determining the appropriate service factor. In simple terms, the service factor is the ratio of the gearbox rated horsepower (or torque) to the application’s required horsepower (or torque). Service factors are defined by the American Gear Manufacturers Association (AGMA), based on the type of gearbox, the expected service duty, and the type of application.

While service factors may seem to be very specific, with thousands of combinations of gearbox types and applications each assigned its own numerical value, the criteria used to determine these values are based not on testing and empirical data, but rather on extensive review and analysis of gearbox manufacturers’ experience.

In general, the horsepower (or torque) rating of a gear tooth is based on the durability of the gear surface — its resistance to pitting — or on its bending fatigue. As the service factor of a gearbox is increased, the relationship between the gear teeth life (based on durability of the gear surface) and load is proportional to the increase in service factor, raised to the 8.78 power. In other words, if the service factor is increased by 30 percent (from 1.0 to 1.30, for example), the gear tooth life will increase 10 times (1.30^8.78 = 10.01).

To determine the gearbox service factor, start by consulting a set of tables or charts provided by the manufacturer, based on the type of gearing (worm, spiral bevel, helical, etc.). These tables list a wide range of applications (conveyors, cranes, winders, saws, blowers, etc.), each with (typically) three levels of service duty the gearbox is expected to see: zero to 3 hours per day; 3 to 10 hours per day; or greater than 10 hours per day. Each of these application-service duty combinations is assigned a recommended service factor.

Remember, the gearbox service factor is much like a safety factor to ensure the gearbox meets the application requirements, taking into account typical operating conditions known to exist for various types of applications. Once the AGMA-recommended service factor is determined, consider other, non-typical, working conditions that can cause additional stress and wear on the gear teeth, bearings, or lubrication. If any of these conditions exist, increase the service factor accordingly to ensure a sufficient safety margin and life of the gearbox.

Gear World is one of the largest and most diverse gear manufacturing companies in North America. We service a wide spectrum of industries, including power generation, mining, timber products, wind, construction, oil and gas, steel, marine, aerospace, and many more. Gearbox services To ensure that our clients’ equipment continues to run at optimal levels, we offer a complete gearbox maintenance services portfolio. Outsourcing maintenance allows our customers to focus on their core competencies and daily operations. Nov 29, 2020 In a typical transmission service, the fluid is completely flushed (including the torque converter), a filter is changed, the transmission pan is cleaned and a new pan gasket installed. Common Problems. Premature transmission failure due to lack of maintenance, low fluid, dirty filter. Onsite gearbox repair, inspection, alignment and commissioning Our service engineers have besides their tremendous commitment and flexibility, also a great knowledge of gearboxes in their specific environment. Often the environment is the basis for earlier failure. In addition to onsite inspections and assembly, we can execute the following.

Gearbox Service Kit

Some conditions that may require an increase in the service factor are:

• Elevated temperatures
• Extreme shock loads or vibrations
• Non-uniform loads (cutting versus conveying, for example)
• Cyclic loads (frequent starts and stops)
• High peak versus continuous loads

Once the appropriate gearbox service factor is determined, multiply the service factor by the horsepower (or torque) required for the application, and the result is the output horsepower (or torque) required by the gearbox.

How does service class differ from service factor?

In some cases, manufacturers cite gearbox “service classes” rather than service factors. Service classes are designated as I, II, or III, and are generally translated to numerical service factors of 1.0, 1.4, and 2.0, respectively, to be used in gearbox sizing calculations. It’s common that even if a manufacturer publishes service classes for general application types, they also publish the more specific service factors for specific applications as well.

Why don’t some catalogs list gearbox service factors?

Using service factor to guide the selection of a gearbox is appropriate for applications driven by traditional AC induction motors. But because gearbox output torque, speed, and inertia are much more critical for the proper operation of a servo system, sizing a so-called “servo-rated” gearbox requires a more detailed and exact method. For gearboxes that are used in servo systems, the primary emphasis in the sizing process is on required torque and inertia match.

For the 8-speed automatic transmission, ZF set out to design and develop an entirely new gear set concept. The result is a revolution in transmission design: a transmission concept with 4 gearsets which requires only 5 shift elements – of which only two are open in any given gear. The 8HP also requires no more than 3 multi-disk clutches and 2 brakes, which allows it to achieve a greater degree of efficiency than other concepts. As a result of the fact that only 2 shift elements are open per gear, drag losses in the transmission are sustainably reduced. This effect is supported by the use of a new parallel-axis vane-type oil pump. 4 A torque range from 300 to 1000 newton meter makes the 8HP the perfect partner for all rear-wheel-drive and all-wheel-drive designs. From the lower midsize segment to sporty luxury cars, and in every type of SUV and offroad vehicle – its revolutionary design is always an efficient and economical solution. Although the 8HP features 2 more speeds than the extremely successful 6HP, the dimensions have remained unchanged and the weight was even reduced by 3% to 87 kg (transmission modular system 8HP70) including oil. At the same time, the total transmission ratio spread of 7.0 ensures that the engine is always in its optimum operating range. This translates into improved acceleration and reduced fuel consumption.

Gearbox Service Factor Calculation

Based on a really successful product, it combines dynamics and comfort with improved efficiency – also with regard to the costs. And it is ideally equipped for even stricter fuel consumption and CO2 emission regulations. In the premium and mid-size car range, the optimized 8HP product family enables the average fuel consumption to be cut by another 3%. CO2 emissions decrease to the same extent. These potentials can also be completely transferred to hybrid drives. Incidentally, additional savings potential by a further optimized startstop function is not yet included here. To achieve these innovations, ZF engineers have optimized some details. Thus, the reduction of drag torques and engine speeds further reduced the already very low power losses. Essential success aspects are the higher transmission ratio spread and the reduction of system pressures in many areas. Another factor is the multidisk separation of the brakes. Furthermore, advanced torsional vibration dampers enable a faster bypassing of the hydrodynamic power transmission and therefore further reduction in speed. Thus, the new 8HP is perfectly prepared for use with the new engines (3-8 cylinders) which will determine the trend of the years-to-come.