Classification stepped transmissions and their requirements

Classification stepped transmissions. Stepped gear classified according to the following features: the mobility of shafts and axles are distinguished from the fixed gear shafts and planetary (with movable axes of the gears of the satellite), and the number of shafts with fixed gear shafts are divided into two-, three-and multi-shaft, by number of steps to move forward gear can be two-, three-, four-, five-and multi-stage (two stage boxes are used in conjunction with the continuously variable transformer) to distinguish non-automatic mode control, semi-automatic and automatic transmissions. Switching gears in a planetary box produce without breaking the flow of power, which contributes to the generator, which facilitates the management of transmission and increases the number of steps, as well as improve the car's dynamic, but it can lead to what you need to repair the generators. However, the planetary gear harder and more expensive, but their overall dimensions and mass are usually somewhat larger than with fixed transmission shafts, the most widespread. Planetary gearboxes are used as the mechanical part of stepless transmissions, as well as speed gearbox with automatic control. Currently the most widely used four-and five-speed gearbox. Multi-stage gearbox with a number of steps 6-15 is set on the trucks and heavy-duty cross-country. Non-automatic gearbox controlled either directly or through an amplifier (hydraulic, pneumatic, vacuum, electromagnetic, or a combination). Requirements for speed gearbox. The main requirements imposed to speed gearbox, should include providing the best traction and fuel and economic properties of the vehicle, high efficiency, ease of management, shock-free gear changes, quiet operation, inability to turn two gears simultaneously or reverse gear while moving forward, reliable retention programs in the included and the neutral position, simple design and low-cost, small size and weight, ease of maintenance and repair, and design reliability. To satisfy the first requirement, it is necessary to choose the number of stages in the gearbox and gear ratios. As the number of steps possible to ensure conditions of the engine close to the most advantageous in terms of agility and fuel efficiency of cars. However, in this case is complicated design, increasing the overall dimensions and weight of the gearbox, as well as difficult to drive. However, the increase in the number of steps usually causes an increase in the time during which the gap flow of power that can affect the dynamic car. Easy to operate manual transmission depends on its design concept, method and type of gear drive switch. This helps the starters in which there are serrated Inside bendeks. Transfer switch with movable gears (carriages), gear couplings, clutch synchromesh, friction or electromagnetic devices. The most simple and compact gearbox with change carriages. However, the carriage can not provide the shock-free gear, so you have to use special methods of switching, slowing down or speeding up the slave of the clutch motor; Durability transmission in this case is completely inadequate. Gear couplings somewhat increase its longevity, as the blows when you switch receives a greater number of teeth of couplings and gear included. However, in this case the strikes did not completely excluded, and the construction of the gearbox is a more complicated. For shock-free gear synchro set, which, however, complicate the design, as well as increase the overall dimensions and weight of the gearbox. Therefore, the most widely used transmission, in which the higher rate: switch synchronizers, and the lower - scalloped sleeves and carriages. In planetary gearbox switches, using friction or electromagnetic devices, sometimes used in transmissions with fixed shafts. Noise of the gearbox, which depends mainly on the type of gear in it, is greatly reduced by replacing spur gears helical or herring-bone (the latter is used very rarely).