The hydraulic steering gear is the hydraulic power steering rack. Steering gear (also often referred to as steering gear) is a set of gear mechanisms that completes from rotary motion to linear motion (or approximately linear motion). It is also a reduction gear in the steering system. It is the most essential part of the steering system. The hydraulic steering gear is a cycloid rotary valve type full hydraulic steering gear composed of a follow-up rotary valve and a cycloid rotary stator pair. It is a fully hydraulic steering system composed of a fuel supply pump, relief valve (or diverter valve), steering cylinder, and other connecting accessories.

1 What is the function of hydraulic?

The function of the hydraulic steering gear is to increase the force transmitted from the steering wheel to the steering transmission mechanism and to change the transmission direction of the force. Widely used in low-speed and heavy-duty vehicles such as agricultural machinery, shipping machinery, garden machinery, road maintenance machinery, forestry machinery, construction machinery, and mining machinery. Through it, the driver can achieve a large steering force control with a small operating force, the performance is safe and reliable, and the operation is light and flexible.

hydraulic steering gear

2 How does hydraulic steering gear work?

1) Working principle:

  1. In the middle position (when the steering wheel is not turned). The oil from the oil pump is returned to the oil tank through the interior of the steering gear.
  2. During power steering, the oil from the oil pump enters the cycloidal pinwheel meshing pair (metering motor) through the follow-up valve and pushes the rotor to rotate with the steering wheel. Depending on the size, orientation, and quantity of the steering angle of the steering wheel, the hydraulic oil is pressed into the cylinder. The left cavity or right cavity pushes the guide wheel to realize power steering. The oil on the other side of the cylinder returns to the tank through the follower valve.
  3. Manual steering. When the engine is turned off, the steering wheel is operated manually, and the rotor of the metering motor is driven to rotate through the valve core, dial pin, and linkage shaft in the steering gear. The metering motor presses the hydraulic oil into the cylinder and pushes the guide wheel to realize manual steering.

The volume difference between the two chambers of the oil cylinder can be replenished from the oil tank through the oil return port. Since the steering gear is used for heavy-duty and low-speed vehicles, in order to prevent the steering wheel from thumping, the structure is designed as an open-ended non-responsive structure, and the external force acting on the guide wheel cannot be transmitted to the steering wheel, and the driver has no road feel.

hydraulic steering gear

2) The hydraulic steering gear is a precise hydraulic component, the following points must be paid attention to when disassembling and assembling:

  1. When disassembling the hydraulic steering gear, it is not allowed to use hard metal objects such as a hammer to hit hard, but a copper rod or a rubber hammer should be used to tap lightly.
  2. The sealing surface or precision mating surface shall not be opened with hard metal such as a screwdriver (commonly known as a screwdriver) to avoid scratching the surface.
  3. Be extra careful when disassembling and assembling to avoid losing or damaging small objects.
  4. All parts should be thoroughly cleaned before assembly. The seals should be coated with lubricating oil during assembly.
  5. Do not wear gloves that are prone to lint, such as cotton thread, during assembly, do not use cotton gauze or other rags to wipe the sealing or precision fitting surfaces, and do not assemble in a dusty environment.