Design; The System Circuit - Danfoss K Frame Series Service Manual

Service Manual
K and L Frame Variable Motors, Cartridge Mount
Introduction

Design

The System circuit

6 | © Danfoss | July 2017
Pressure measurement / gauge location or specification
The symbols above appear in the illustrations and text of this manual. They are intended to communicate
helpful information at the point where it is most useful to the reader. In most instances, the appearance
of the symbol itself denotes its meaning. The legend above defines each symbol and explains its purpose.
K and L Frame Variable Motors (KC/LC) are low to medium power, two-position axial piston motors
incorporating an integral servo piston. They are designed for operation in both open and closed circuit
applications. KC/LC motors have a cartridge style mounting configuration. The standard control is a direct
acting single line hydraulic control. The integral servo piston controls motor displacement.
The motor is spring biased to maximum displacement and hydraulically shifted to minimum
displacement. Minimum and maximum displacement can be set with fixed internal stops. The large
diameter servo piston allows smooth acceleration and deceleration with relatively large circuit orificing.
The motor is ideally configured for installations requiring compact packaging and optimized plumbing,
such as wheel ends. One face of the motor contains all hydraulic porting.
KC/LC cross section
Servo piston
Bias spring
Cylinder
block
Endcap
Valve plate
The circuit below shows the KC/LC motor in a simple closed-loop hydrostatic propel application. The
motor is driven by a Series 42 medium power axial piston pump with manual displacement control.
Control pressure applied through an external control valve shifts the motor to minimum displacement;
spring force returns the motor to maximum displacement in the absence of control input.
Swashplate
Bearing
Slipper
Piston
Output
shaft
Shaft
seal
P104 161E
520L0631 | AX00000042en-US0402