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Shaft misalignment accounts for about half of all hydraulic pump failures. This is because the shaft and the bearings are on different planes. As a result, the pump’s bearing load capacities and output are altered, so they are less efficient.
 
All types of hydraulic pumps use bearings to support the shaft. If there is a misalignment of the shaft, it can cause the bearings also to become damaged. The misalignment of the key moving parts and components inside the hydraulic pump will affect pump performance and bearing life.
 

How Properly Aligned Pumps Function

When the shaft and bearings of a pump are functioning correctly, there will be a minutel gap between the pump shaft and bearings. When an angular misalignment occurs, the gap will no longer be even. The shaft will touch against the bearings and rub against them.
 
Gradually, the moving parts will create friction and wear on each other. Friction can create additional heat and cause overheating problems.  Furthermore, small metallic shavings can flake off the shaft and bearings, allowing them to get into hydraulic fluid and contaminate it.
 
These shavings can become stuck inside hoses, valves, and other such locations within the hydraulic system. As a result, pump efficiency and fluid power output are reduced. Therefore, the excessive wear on the shaft and pump bearings will cause premature pump failure. 
 

Signs of Misalignment in a Hydraulic Pump

When the bearings are misaligned, they will shorten the pump’s life. However, there are some things you can do to help prevent misalignment issues.  Special tools are used with predictive maintenance that allow you to check vibration, heat, and other measures to verify if there could be a misalignment.
 
The most common sign of pump misalignment is detected through vibration. Therefore, It is best to take a baseline reading when installing a new pump since there will be some pump vibration with a perfectly aligned pump.
 
Friction and vibration go hand-in-hand. As the friction between the moving parts increases, so do the vibrations. Should you notice the pump’s vibrations seem louder, then you should take a vibration reading and compare it to your baseline reading.  If it suggests pump misalignment, then you need to realign the pump.
 
Another sign that could indicate an alignment problem is finding metal shavings in the hydraulic fluid. While there could be other causes for metal shavings, they often imply misalignment in pumps and motors where two metal components are rubbing together.
 
The worst mistake you can make is to wait until you notice load-bearing problems or experience a pump failure. Doing so results in reactive maintenance and unwanted downtime.
 

How to Ensure Precision Alignment

The best way to ensure precision alignment is to use close couplings to connect the pump and motor together. This creates a secure connection and proper alignment. However, this method is not always feasible for every hydraulic configuration.
 
When close coupling cannot be used, then long coupling is your best option using a flexible or fixed coupling. However, since the hold is not as secure, misalignment is still possible. To verify shafts and couplings are properly aligned, you should use laser shaft alignment.
 
Laser shaft alignment allows you to align the shaft easily and pump to the micrometre. It is also the preferred alignment method since it is one of the most cost-effective methods to use.
 

Misalignment Hydraulic Pump Review

By using these methods and tools as part of your predictive maintenance plan, you can better identify and correct misalignments when they occur. Addressing misalignment problems early ensures you get the most life out of your hydraulic pumps.
 
Should you require replacement pumps for your hydraulic systems, we offer a wide range of different types of hydraulic pumps, as well as motors, accessories, and other hydraulic products. Please register online or call White House Products, Ltd. at +44 (0) 1475 742500 today!