Farm Tractor 75hp COC With Cabin

The characteristics of an open-center hydraulic system: simple structure; pump deload in the neutral position, resulting in low power loss. However, it is not suitable for simultaneously operating several actuators to meet multi-functional requirements.

The characteristics of a closed-center system: requires a variable displacement pump; has a more complex structure; but can meet the needs of multi-functional systems.

1. Height Adjustment: Agricultural implements are equipped with ground rollers, and the tillage depth is controlled by the position of the ground rollers, which are adjustable. Height adjustment can be achieved with any hydraulic system; the hydraulic system should be in a "floating" state. Due to the contour-following action of the ground rollers, the tillage depth is uniform, resulting in good tillage quality. When soil resistance varies greatly, the contour-following effect weakens, and the engine load also increases, affecting tillage quality and productivity. Since the implement weight is supported by the ground rollers and not transferred to the tractor, it is detrimental to improving traction performance.

2. Position Adjustment: The implements do not require ground wheels and are suspended in a predetermined position by a hydraulic suspension system, temporarily fixing their height relative to the tractor to control tillage depth or working height. This position is controlled by the driver. A position sensor mechanism automatically maintains the height using the hydraulic system. When using position adjustment, the hydraulic cylinder maintains a certain pressure during operation, fully utilizing the weight of the suspended implements and tillage resistance to increase the load on the drive wheels, thereby improving traction. However, changes in soil resistance cause changes in traction resistance, resulting in changes in engine load, requiring the driver to frequently adjust the tillage depth. On uneven ground, the machine is affected by bumps, resulting in poor work quality; it is only suitable for inter-row cultivation, weeding, harvesting, and tillage on leveled land.

3. Resistance Adjustment: This system automatically adjusts tillage depth by utilizing changes in implement resistance to maintain a relatively constant tillage resistance. The hydraulic cylinders maintain a certain pressure during operation, fully utilizing the weight of the implements and tillage resistance to increase the load on the drive wheels, thereby improving traction and reducing the impact of uneven ground on tillage depth. Suitable for tillage operations. However, when resistance changes are small, the automatic adjustment of tillage depth is not sensitive, making it unsuitable for shallow tillage. When soil resistance changes significantly, resistance adjustment leads to uneven tillage depth. Resistance control, to maintain a near-constant tractor traction and stable engine load, requires slight adjustment of the implements if soil resistance changes during tillage. This adjustment is automatically controlled by the hydraulic suspension system. Resistance control is mainly used for plowing, harrowing, deep tillage, and other tillage operations involving implements. Its advantages are: it can automatically maintain stable tractor traction; although the implements have no ground wheels, they still have a certain conforming effect under the undulation of the ground, and can maintain uniform tillage depth on flat cultivated land; during tillage, the weight of the implements can be transferred to the tractor drive wheels, which is beneficial to improving the tractor's adhesion performance; it does not require a solid ground as a benchmark for tillage depth, so it can adapt to the needs of paddy field tillage.

4. Combined Force and Position Adjustment: This integrates resistance and position adjustment. When the working resistance of the implement changes, the hydraulic system automatically raises or lowers the implement to prevent changes in the tractor's traction load. However, the raising and lowering of the implement is also somewhat suppressed to prevent excessive changes in tillage depth. The aim is to balance the stability of the traction load and the uniformity of tillage depth, improving the adaptability of automatic tillage depth control and achieving high tillage quality under various soil conditions. The driver can adjust the force-position ratio as needed to obtain better overall performance.