Hydraulic Motor China – Hydraulic Motor Housing Drain: Optional


When the hydraulic motor housing drain is optional – unless you want reliability!

Hydraulic Motor China     point out: “Without axial, radial or curved shaft design, unrestricted housing drains are critical for piston-type hydraulic motors. But for gear designs – external, internal and geared rotors, housing is generally considered – Drain lines are optional. This is because these types of motors do not have large capacity housings or sump like piston motors. However, they do have internal leaks, and their design usually accumulates in a small cavity before the shaft seal. in.”

In theory, by installing a high pressure shaft seal and two check valves, the internal leak is discharged into the return line (which is unacceptable for the piston motor or pump). This is why dedicated drains are generally considered optional.

Internally circulated gear motor configuration

However, if reliability is the most important criterion, then the hydraulic motor professional manufacturing designer explained:

“Our part of our design for the rig is to install two low-speed, high-torque (large-rotor) motors on the front of the rig to turn the shaft with a wire rope brush to clean the rig. Drill The early design did not have a casing drain because the motor did not need it according to the specifications. But after the shaft seal leaked several failed motors I suggested that we install the casing drain. This means quite a lot of extra work and materials (hose, Brackets, fittings, etc.) return the oil to the tank, but problems have been eliminated since then. Any machine that we make this modification now includes a standard motor drain.

This problem is one of the many obvious conflicts in hydraulic systems, according to the component manufacturer and the best way to achieve the best reliability. Another example that comes to mind is that most pump manufacturers can let the pump “lift” its oil from the tank. In other words, install the pump above the minimum oil level. However, if you want the pump to last as long as possible, you will give it an overflow inlet (the oil head above the pump head).

Of course, there are exceptions to any rule. You may have installed a pump above the tank that looks good to rust before it needs to be replaced. Or a swing motor without a dedicated drain, which never leaks from the shaft seal, seems unlikely. But the strange exception is not because you have not followed best practices. Especially if optimizing reliability is your biggest concern