General Description - Sauer Danfoss 51 Series Manual

GROUP 3025

2 GENERAL DESCRIPTION

The Series 51 variable displacement hydraulic motor
uses spherical pistons and piston rings. The angle
between the cylinder block and the output shaft can be
o o
set between 32 and 6 , providing a 5 to 1 maximum to
minimum displacement ratio.
At maximum displacement, the motor will provide a
certain maximum ouput shaft torque and minimum
speed corresponding to the pressure and flow supplied
to the motor. Under the same input conditions but at
minimum displacement, the shaft speed will be
approximately one--fifth the full displacement value.
The displacement is changed by a servo piston which is
connected to the valve segment.
Control
Pressure
Port
3025- -9A, Page 4
Pressure
Compensator
Hydraulic
Override
Proportional
Control
Servo Piston
Cylinder
Charge Pressure
Relief Valve
Figure 1. Sectional View of Series 51 with Hydraulic Proportional Control
An electrohydraulic control is mounted on the motor end
cap to control the servo piston and the motor
displacement. Servo pressure oil is supplied externally
from the hydraulic reservoir pump.
A synchronizing shaft,
synchronizes the rotation of the output shaft and the
cylinder block. The ball end of each piston runs in a
socket bushing pressed into the output shaft. There are
no other parts used to connect the pistons to the shaft.
Two tapered roller bearings support the output shaft.
Minimum Displacement Limiter
Valve Segment
Bearing Plate
Tapered Roller Bearings
Piston
HYDRAULIC PUMP
with spherical rollers,
Synchronizing Shaft