What Are The Main Components Of A Tractor?
Tractors have come a long way in the past 20 years. Today, even the smallest yard tractor has complex hydraulic systems and trick differentials. While this has brought productivity enhancements across the farm, it makes life difficult for farmers who prefer to repair their own vehicles.
But there is nothing to worry about. While tractors come in different shapes and sizes, broadly speaking, they all contain the same components. So in this guide, we will look at the basic components of a modern tractor. This should help you identify what is wrong with your tractor and ensure you get the right parts to get it fixed as quickly as possible.
Cab & controls
The cab is where the operator controls the tractor and any connected implements. Most modern tractors have a closed cab for driver comfort. The cab itself can be made from either metal or GRP panels and sits on mounting bushes to reduce vibration.
The instrument panel is where the controls are for the tractor. Most tractors have separate fuel and temperature gauges along with a speedometer and rev counter.
The linkage controls are usually located to the left of the driver. These consist of hydraulic levers that can be used to attach various implements. The tractor's PTO controls are also located here for ease of use.
The front axle provides a mounting point for the front wheels. Most front axles consist of either a rigid tubular construction or I-section steel which pivots in the middle. The front axle also contains the front differential that distributes power to the wheels via a drive shaft.
The rear axle provides a mounting point for the rear wheels. Most of the tractor's drive is delivered through the rear axle so it’s much stronger than the front axle. The rear axle also contains the rear differential which delivers drive via a linkage.
The differential serves two purposes. It delivers drive from the engine and allows both wheels on the axle to rotate at different speeds. This is required because during a turn, the outside wheel has further to travel than the inside wheel.
Most tractors have a steering box that contains the drag link, kingpin and steering gears. Some modern tractors have 4-wheel steering. In this case, there is no steering box as the wheels are controlled independently using the tractor's hydraulic system.
Modern tractors use either wet or dry braking systems. Dry braking systems consist of a drum or disc attached to the drive axle. Wet braking systems consist of a set of discs sealed inside a drum filled with gear oil. This helps to dissipate heat and keep dirt out.
The layout of most tractors hasn’t changed much in 70 years. The engine is mounted longitudinally up front and provides drive to the gearbox behind. The engine also serves as a mounting point for the water pump, hydraulic pump and alternator.
A traditional gearbox consists of a set of gears, shafts and bearings that deliver power from the engine to the drive axle. But most modern tractors have a CVT gearbox that uses a single belt in place of multiple gears.
The clutch connects the drive from the engine to the gearbox. Most modern tractors use a fluid clutch, not a friction clutch like the one in your car. This allows more power to be transferred at low revs.
The PTO (Power Take-Off) connects to the transmission to provide power to attached implements. Most tractors have a single rear PTO, but some tractors also have a front PTO. This allows implements to be connected to both the front and rear of the tractor.
Most tractors use a hydraulic gear pump to generate pressure in the hydraulic system. The power of the pump varies depending on the size of the tractor, but you can expect anything from 150 to 200 kg/cm2.
The hydraulic cylinder, sometimes called a RAM cylinder, transmits fluid from the piston to the hydraulic arm. The increase in pressure causes the arm to lift when required by the operator.
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