• Sealing components, such as gaskets, o-rings and seals
• Hardware, such as screws, bolts, washers and other fasteners
• Gears, especially those with wear, backlash or broken teeth
• Oil seals on shaft ends

Cleaning

Next, we clean and inspect each part. For hydraulic motors that have fluid or oil constantly flowing over parts, removing oil buildup allows us to more closely evaluate the condition of the motor parts. Hydraulic oil, fluid or cleaning agents can contaminate the interior of a hydraulic motor. Cleaning off these contaminants can reduce friction and improve the efficiency of the motor.

Testing Electronics

Electronics that regulate the motor operation require inspection and testing. With this step, the technician can better find the source of motor issues. In some cases, the motor may only require repairs of the electronics to restore operation.

Restoring Moving Parts

Over time, the constant movement of pistons and shafts can lead to surface scoring. Our technicians have several methods available to remove the scoring. Occasionally honing or polishing will remove minor pitting and scoring. For more serious cases, we can recoat the surface with chrome.

Just as we work to restore the pistons and shafts, we do the same for cylinders and any other contact points. We may need to machine damaged cylinders or replace broken shafts in them. Lastly, for gear motors, we examine the integrity of the teeth and replace worn or damaged gears to restore operation.

Replacing Bearings and Worn Seals

All seals, bearings and gaskets that show signs of wear will have new parts installed to replace them. Worn components such as these can cause fluid leaks that compromise the efficiency of the entire motor operation.

How Hydraulic Motors Work

Hydraulic motors use liquid and pressure to multiply forces, allowing these systems to move heavy parts with little effort. Hydraulic motors differ from hydraulic pumps in that instead of converting the mechanical energy into pressure and flow, they convert pressure and flow into mechanical energy. A hydraulic motor usually needs a pump as one of its components to ensure it has a properly pressurized flow of oil or fluid.

Generally, hydraulic motors fall into one of three categories — gear, vane and piston motors. All types of hydraulic motors have either fixed or variable displacement. Fixed displacement has a constant torque and speed whereas the variable displacement can create different speeds and torque — or twisting force.

Generally, gear motors have the most cost-effective prices and work optimally when operated with medium flows and pressures. These types of hydraulic motors use a pair of gears — the idler gear and the driven gear. The driven gear connects to the output shaft to create the work needed as this gear turns.

To operate, high-pressure hydraulic oil moves into the gear housing and around the gears. A naturally created pressure differential between the high-pressure incoming oil and the low-pressure outlet keeps oil in the system. However, this type of motor requires close monitoring and maintenance to avoid oil leakages. The most common components to fail in these types of motors are the bushings and housing, which wear out long before major failure of the gears and other parts of the motor.

Vane motors fall into the middle of cost and operation settings. These motors use a rotor on a drive shaft. Slots on the rotor fit into the vanes that move in and out as the rotor turns around the shaft. When the vanes are extended, oil flows through them to the inlet or outlet beneath. When compressed, they block oil flow. Vanes located opposite each other on the rotor move in the same direction to create diametric balance.

Pressurized oil moves into the vane motor through an inlet. From there, it causes the rotor to turn unevenly, causing the vanes around the sides to compress or extend depending on the location of the rotor. The unbalanced movement causes single-direction rotation of the rotor. Generally, vane motors do not operate well at low speeds, with the exception of a few models that operate with high displacement and low speed. These motors also have a medium life span compared to piston and gear motors.

Piston motors may cost more than other types. However, these motors offer better efficiency and can handle high pressures and flows. This category of motors has several subtypes, including axial, radial and less common designs.

For axial motors, the pistons have a circular orientation inside the housing. A shaft rotates the housing, causing the pistons to pump. Within this subtype, the motors may have a swashplate design where the shaft and pistons have a parallel arrangement with each other. Bent axis axial piston motors have the shaft and pistons angled to each other.

Radial piston motors have the pistons arranged perpendicular to the shaft in a circle. When the shaft turns and fluid enters the center, it forces the pistons to push outward against the thrust ring surrounding the shaft. This pushing of some pistons causes the cylindrical barrel that holds them to rotate around the driveshaft. This type of piston motor has a long life, good efficiency and high torque at lower speeds. For operations at lower speeds, radial piston motors will operate better than axial motors.