Specifications

GOLDCUP CONTROLS SECONDARY CONTROLS
CODE **4 - TORQUE LIMITER
OPTION
S23-12299
Both sides of center
S23-12298
“A” Mounting CCW Rotation
“B” Mounting CW Rotation
S23-12300
“A Mounting CW Rotation
“B Mounting CCW Rotation
DESCRIPTION
DISASSEMBLY
See S23-12299
REWORK OF WEAR PARTS
The torque limiter override hydraulically limits the maximum shaft torque imposed by
the pump load at all speeds.
This operation is in addition to the pressure compensator override. It limits the com-
pensating pressure in proportion to displacement so that the product of pressure and
displacement, P x Q, does not exceed the set value.
A fixed flow of servo oil is applied to the end of a spool. A stroke controlled orifice
meters this flow to the pump case, establishing a pressure on the end of the spool.
System pressure is applied to the end of a pin in contact with the opposite end of the
spool. A port opens to allow system pressure into the control chamber to de-stroke
the pump whenever the force on the 1/8” (3.18mm) dia. pin overcomes the force on the
end of the 7/16” (11.1mm) dia. spool.
The area of the orifice is varied by the pump stroke in such a manner that the pressure
developed will be inversely proportional to stroke. For example, at 1/2 stroke, the pres-
sure will be twice the pressure at full stroke. At 1/3 stroke, the pressure will be 3 times
the pressure at full stroke. An adjustable flow control establishes the pilot flow, and
thereby the controlled torque value. An adjustable restriction in series with the stroke
controlled orifice permits adjustment of linearity.
For limiting on both system ports, two independent torque limiters are required. The
control contains both in the same body.
The one side of center control contains one torque limiter, to limit the “A” system port.
1. Disconnect tubing lines from pump. Remove screws (2). Remove control from
pump.
2. Remove indicator (39). Remove retaining ring (3) and press the shaft assembly
through the valve body.
3. Examine shoes (7) and (41) for contamination in balance pads or excessive
scratching on faces. Note: the two shoes are not identical and must be installed in the
proper position on reassembly.
4. Remove the bodies (27) with attached parts. Remove the spools (25). Examine
spools and bores for free motion, wear or contamination.
5. Remove cover nuts (36) and screws (35).
6. Remove plug (34), spring (32), retainer (31) and filter assembly (28). Examine filter
assembly carefully for contamination.
7. Remove cover nuts (38) and screws (44).
8. Remove plugs (21) springs (19) and spools (18).
9. Solvent wash and check all passageways for free flow.
Preparation for assembly
All parts are to be inspected and be free of material defects, dirt, scratches or any for-
eign material.
All parts are to be cleaned with a suitable cleaning solvent and all cores and passages
blown out with clean dry compressed air.
After cleaning and inspection, all parts are to be covered with a light film of oil and
should be protected from dirt and excessive handling until assembled onto the unit.
During assembly, lapped and ground surfaces should be kept lubricated and protected
from nicks or surface damage.
101
Description Rework
Servo plate face Fine stone to remove raised burrs & dings
Shear seal Fine stone to remove raised burrs & dings. Note:
grooves to supply balance pads must be present
and adequate.
Control cover Stone or lap inside face to remove raised burrs &
dings.
Spool Break sharp edges or dings.