SM11-011-0
Page 3
DESCRIPTION
The vane type motor is a fixed displacement, rotary
plate assembly consisting of the port plate with a
balanced motor that converts hydraulic oil flow into
built-in check valve, a cam ring assembly containing
rotary mechanical motion. The motor consists of four
the rotor, vanes, vane springs and cam ring, and the
basic sub-assemblies; a body or housing and shaft
end cap assembly consisting of the end cap and nee-
with a permanently lubricated bearing, a front port
dle bearing.
THEORY OF OPERATION
During operation, hydraulic oil flows through either
pressure applied against the vanes forces the rotor to
one of the two ports in the end cap and is directed to
turn and at the same time rotates the motor shaft. As
both sides of the cam ring assembly through the cast
the rotor turns, the oil moves to the discharge ports in
ports in the end cap and port plate assembly. The
the port plate and end cap.
MAI NTENANCE
TROUBLESHOOTING.
SYMPTOM
PROBABLE CAUSE
SOLUTION
1
External leakage.
a.
Seal failure.
a.
Replace seal.
b.
Defective casting.
b.
Replace casting.
2.
Leakage at fittings,
a. Cracked casting.
a.
Replace.
b. Defective threads.
b.
Replace.
c.
Damaged O-ring.
c.
Replace.
d.
Burr.
d. Stone or file flat.
3.
Loss in speed under load,
a.
Low inlet pressure.
a. Check pressure.
b. Excessive back-pressure at out-
b. Check pressure-increase line
let.
size.
c. Scored port plate or end cap.
c.
Relap flat to clean up.
d.
High oil temperature.
d. Use heavier oil; use oil cooler;
adjust relief valve setting.
