|Cavco Machine Tool Rebuilding Maintenance Tips: Close Coupled Hydraulic Pump / Motor Failures|
Cavco Machine Tool Rebuilding News
There are no “simple motor bearing failures” or “simple hydraulic pump failures,” if one or the other fails, when they are close coupled. One invariably takes out the other.
You'll recognize a close coupled hydraulic pump/motor assembly (or any close coupled assembly for that matter) when the motor shaft does not extend out of the front motor housing. Instead it is bored and broached to accept the keyed input shaft of the pump. It is cheaper to produce but when it fails, it can cause extensive down time for the following reasons:
- When a front motor bearing fails, the heat will destroy the front
seal of the pump.
We have seen all of the above while repairing machines in the field. A “simple motor bearing failure” takes more than a week of down time, even though parts are flown in from all over the country. Recently, we had a motor bearing seize and spin on the motor shaft. This clamped the input shaft of the pump in the motor. The motor and the pump had to be cut apart, which proved to be a waste of time since both were NG.
We have seen so many problems in the field with close coupled pumps/motors, we now advise our customers to replace those assemblies with a standard motor, pump, three piece coupling and interface, to avoid unacceptable down time with critical machines.
Contact Cavco Machine tool Rebuilding at 860-355-1382 for further information