Hydraulic Motor Type

Vane motor
The vane motor consists of a housing with eccentric holes in which a rotor runs, the blades of which slide in and out. The force difference created by the unbalanced force of the pressurized fluid acting on the blades causes the rotor to rotate in one direction. A key element in vane motor design is how the blade tip is machined at the point of contact between the blade tip and the motor housing. Several types of "lip" designs are used, with the primary purpose of providing a tight seal inside the motor housing and between the blades while minimizing wear and metal-to-metal contact.

 

Gear motor
The gear motor (external gear) consists of two gears, a driven gear (connected to the output shaft by keys, etc.) and an idler wheel. The high-pressure oil is injected into one side of the gear, where it flows around the xxx of the gear, between the tip of the gear and the wall shell in which it is located, to the exit. The gears then mesh, not allowing oil flow from the outlet side back to the inlet side. For lubrication, gear motors use a small amount of oil from the pressurized side of the gear, drain it through a (usually) hydrodynamic bearing, and discharge the same oil to the low-pressure side of the gear, or through a port on a dedicated drain motor housing, which is typically connected to the line that drains the motor housing pressure to the system's reservoir. A particularly positive feature of gear motors is that catastrophic failure is rarer than most other types of hydraulic motors. This is because the gear gradually wears out the housing and/or main bushing, gradually reducing the volumetric efficiency of the motor until it is almost useless. This usually occurs long before wear causes the unit to get stuck or damaged.

 

Rotor motor
The gear rotor motor of the hydraulic motor is essentially a rotor with N-1 teeth, and the rotor/stator rotates with N teeth off-center position. A plate dispenser valve placed axially is (usually) used to direct pressurized fluid into the assembly. Several different designs exist, such as Geroller (internal or external rollers) and Nichols motors. Generally, cycloid motors are medium to low speed and medium to high torque.

 

Axial piston motor
For high-quality rotary drive systems, piston motors are usually used. Hydraulic pumps range in speed from 1200 to 1800rpm, while machinery driven by motors usually requires much lower speeds. This means that when using an axial piston motor (xxx displacement of 2 liters), a gearbox is usually required. For continuously adjustable sweep volumes, an axial piston motor is used.

As with piston (reciprocating) pumps, piston motors are most commonly designed to be axial. This type of motor is most commonly used in hydraulic systems. Like their pump counterparts, these motors are available in variable and fixed displacement designs. Typical usable (within acceptable efficiency range) rotational speeds range from less than 50 rpm to above 14,000 rpm. Efficiency and minimum/xxx rpm largely depend on the design of the rotary group, and many different types are used.