Case CX130 CX160 CX210 CX240 Mini Excavator Service Manal
All of the CX Series Excavators use an open center hydraulic system, in that there is always an output flow from the hydraulic pump flowing through the system.
CX130, CX160, CX210, CX240
CX160 CX210 CX240
Make
Model
CASE
4TA390
CASE
4TA390
CASE
6TAA590
CASE
6TAA590
HP (net) 106 106 138 163
Cold Start Ether Ether Electric Electric
Rated rpm 2200 2200 1950 2150
TABLE OF CONTENTS
Section 1 – General Introduction
PAGE NO.
Engines .
Reservoir.
Filters .
Pumps.
Pilot System
Hydraulic Systems
Cushion Control
Swing
Travel
Cylinders
Electrical System.
Case CX130 CX160 CX210 CX240 Mini Excavator Service Manal
The CX Series Excavators use a variable volume piston pump system to be able to fully use the engine horsepower available. As the system operating pressure increases, the flow gradually reduces, to maintain a constant horsepower load on the engine.
The theory is that when very high pressures are required, speed isn’t so important.
The CX Series Excavators use a twosection variable displacement piston pump, to provide the flow required to operate the functions.
Variable pumps are used to allow the delivery of a higher flow rate at lower
working pressures, and then allow the pump to reduce flow at higher pressures to keep from stalling the engine. The increased flow at lower pressures makes the machine cycle faster, to increase the overall efficiency of the machine.
The engine horsepower required to drive a hydraulic pump depends on the flow delivered by the pump, as well as the pressure at which system is operating. There is a mathematical formula to calculate the pump drive horsepower, but a rule of thumb to visualize this, is that it requires approximately 1 engine horsepower to deliver 1 gallon per minute of oil at 1500 psi.
Therefore, it would require 25 HP to deliver 25 GPM at 1500 psi. If the pressure increases to 3000 psi, the requirement would be 50 HP.
The CX Series Excavators have an automatic pump de-stroke feature that reduces pump
flow to a minimum delivery when all control levers are in the neutral position. This is
accomplished with a hydraulic pilot signal from the control valve. This system saves fuel and eliminates wasted engine and hydraulic power.
The minimum flow delivery of the pumps increases with machine size and engine horsepower. Although the pump configuration and manufacturer varies, in principal, all of the pump control systems operate the same.
Case CX130 CX160 CX210 CX240 Mini Excavator Service Manal