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Cross section view
Swashplate
Cylinder block
Auxiliary mounting pad “B”
Charge pump
Servo piston
Piston
Shaf t seal
Shaf t
Slippe r
Electric displacement control
P106 045E
Valve plate
Swashplate feedback pin
The Basic Closed Circuit
Hydraulic lines connect the main ports of the pump to the main ports of the motor. Fluid flows in either
direction from the pump to the motor and back. Either of the hydraulic lines can be under high pressure.
In pumping mode the position of the pump swashplate determines which line is high pressure as well as
the direction of fluid flow.
Case Drain and Heat Exchanger
The pump and motor require case drain lines to remove hot fluid from the system. The pump and motor
drain from the topmost port to ensure the cases remain full of fluid.
The motor case drain can connect to the lower drain port on the pump housing or it can tee into the case
drain line upstream of the heat exchanger. A heat exchanger with bypass valve cools the case drain fluid
before it returns to the reservoir.
Service Manual
H1P 069—H1P 280 Axial Piston Single Pumps
Introduction
©
Danfoss | January 2021
AX152886482551en-000601 | 9