In the world of hydraulic systems, every detail is related to the reliability and operating efficiency of the system. Although the Case Drain on the hydraulic motor is often overlooked, it can affect the long life and smooth operation of the hydraulic motor. What exactly is Case Drain? What role does it play in the hydraulic motor? Why can't it be ignored when purchasing?
What is hydraulic motor Case Drain?
Case Drain, also known as "case drain" or "drain pipe", is a special drain port set on the hydraulic motor housing to discharge the hydraulic oil generated by internal leakage of the hydraulic motor. This leakage is not a system failure, but an internal leakage oil generated during the normal operation of the internal components of the hydraulic motor (such as shafts, bearings, pistons, and seals). It helps to:
lubricate internal structural parts
cool moving parts
balance internal pressure
If these leaked oils are not discharged in time, they will accumulate in the motor housing, causing more serious consequences.
The main role of Case Drain
1. Prevent seal damage
If hydraulic oil accumulates in the housing, it will cause the internal pressure to rise, thereby breaking the oil seal or seal. Case Drain can lead these leaked oil back to the oil tank in time to avoid seal failure caused by overpressure in the motor.
2. Improve lubrication and cooling efficiency
The experience of Poocca hydraulic manufacturers shows that a good oil drain circuit can ensure that a certain amount of oil flows inside the motor at all times, thereby removing heat, extending the service life of bearings and friction parts, and improving the overall efficiency of the system.
3. Realize condition monitoring
By monitoring the flow or oil state of the Case Drain, it can be determined whether there is wear or failure inside the motor. This is often used in the equipment health diagnosis service provided by Poocca hydraulic manufacturers to customers, and is a practical predictive maintenance method.
4. Ensure normal start and operation of the motor
Especially in a closed-loop system, if there is no Case Drain, the hydraulic motor will not start normally or the speed will be abnormal due to the residual pressure in the shell. The high-end motor series such as Poclain and Rexroth provided by Poocca hydraulic manufacturers clearly recommend connecting the oil drain line to ensure stable operation.
Which motors need Case Drain?
Not all hydraulic motors are required to use motor Case Drain, but it is recommended to be connected in the following situations:
High-pressure plunger motors (such as Rexroth A2FM, Poclain MS series)
Hydraulic motors used in closed-loop systems
Motors that work continuously under high load for a long time
Application scenarios with high speed and large displacement
Parker TE/TG motors, Eaton 5433 motors and MS hydraulic motors sold by Poocca Hydraulic Manufacturer are all equipped with dedicated Case Drain interfaces and provide detailed installation instructions.
The correct way to install motor Case Drain
In order to achieve the best effect of Case Drain, it is recommended to follow the following specifications during installation:
The oil drain pipe must return directly to the oil tank to avoid connecting other equipment in series
The oil return position should be higher than the oil tank level to avoid backflow or back pressure
Use hoses and connectors of appropriate sizes to ensure smooth oil return
Avoid excessive length or excessive bends in the oil drain pipe
Install a back pressure valve when necessary to control the oil drain pressure within a reasonable range
Poocca Hydraulic Manufacturer provides a complete set of oil drain pipe design suggestions for global customers to ensure worry-free use of motors and reduce subsequent maintenance costs.
Consequences of Ignoring Case Drain
If the Case Drain interface is ignored during the selection or installation process, the following problems may occur:
Oil seal rupture, motor oil leakage
Motor overheating leads to reduced efficiency
Poor bearing lubrication leads to early failure
Warranty clause invalidation: Many manufacturers will refuse warranty due to failure to connect the drain
Poocca hydraulic manufacturers will clearly inform customers whether Case Drain is required when selling products, and will include technical parameter tables and installation drawings when shipping to ensure that customers use the specifications and avoid unexpected losses.
Recommended hydraulic motor models with Case Drain interface
Poocca hydraulic manufacturers have rich inventory and complete models. The following products are equipped with standard drain ports and are suitable for various medium and high pressure conditions:
Rexroth A2FM / A6VM motor series
Parker TE / TG motor series
Poclain MS02 / MS08 / MS18 / MS35 series motors
Eaton Char-Lynn hydraulic motors
Support OEM customization, delivery within 24 hours, matching flanges, seals and installation services.
Conclusion: Small diameter, big effect
If you have any needs, please contact us for consultation and purchase
Don't underestimate this small case drain interface, it is directly related to the stability, life and maintenance cost of the hydraulic motor. As a system designer or person in charge of hydraulic procurement, choosing a high-quality hydraulic motor with a standard case drain interface is a very cost-effective investment.
