Steering Cylinders: Safe Around Every Turn

In cars and trucks, rack-and-pinion steering is standard. Although it is supported in many cases by a hydraulic cylinder, steering linkages and the rack-and-pinion remain the core components in these fast and relatively light vehicles. However, for heavy work machines such as tractors, wheel excavators, or rough-terrain forklifts, rack-and-pinion steering is too capricious and prone to wear. Therefore, hydraulic steering was invented for these highly stressed machines. Its core component is the steering cylinder.

Structure and Function of the Steering Cylinder

The steering cylinder is a conventional hydraulic cylinder that can be mounted rotatably on both sides along the horizontal axis. For lighter vehicles, a threaded pin is attached on both sides for this horizontal rotation. Larger machines are mounted with a double-eye pin connection.

Technically, the steering cylinder is a simple, double-acting hydraulic linear motor. It consists of a housing, two valves, and a piston rod with double sealing. Hydraulic oil is introduced, extracted, or held via hydraulic lines and a control valve. Therefore, the operation of the steering cylinder requires a hydraulic pump and all other components of a powerful hydraulic system.

Advantages of the Steering Cylinder

Operating a steering axle with a hydraulic linear motor is structurally quite simple. This is why many of these work vehicles are equipped with four-wheel steering. This allows for an astonishingly small turning radius even for very large and heavy equipment. The larger a work vehicle is, the more likely it is equipped with all-wheel steering. Dump trucks practically have this feature as standard.

Steering cylinders can be precisely controlled and maintain the steering angle with great force and reliability. This makes maneuvering in difficult terrain comfortable and safe.

The exposed position of the steering cylinders makes them easy to maintain. They are easily accessible and can be visually inspected as part of a daily check. In case of detected leaks or other defects, the steering cylinders can be removed and replaced with an intact component within a few minutes.

Unless they are bent or the housing has a crack, defects in steering cylinders are usually found in the seals. These can be easily replaced. A leaking steering cylinder is therefore far from being scrap, but can usually be repaired many times with a few simple steps.

Their greatest advantage is the force they can generate and transmit. With their help, steering large and heavy wheels is only possible. After steering with steering cylinders, only track steering, as known from tracked vehicles, is available for navigating heavy vehicles. In this case, one track must always be blocked and the other operated to change the vehicle’s direction. This always severely damages the ground. This tearing up of the topsoil is avoided by using steering cylinders.

Disadvantages of the Steering Cylinder

Hydraulic steering cylinders can transmit large forces, but they are very large and heavy. In addition, they work comparatively slowly. They are therefore only suitable for construction and work vehicles. Their reaction time is too sluggish for higher speeds. Therefore, they are not installed in cars or trucks. Furthermore, a hydraulic system is always required for their operation.

Areas of Application for Steering Cylinders

Typical vehicles steered with hydraulic linear motors include tractors, wheel excavators, wheel loaders, dump trucks, rough-terrain forklifts, heavy industrial forklifts, and other heavy work vehicles.