Operating Principle; When Spool Is In Neutral Position - SANY SY195C9 Shop Manual

Structure and Function

4.5.2 Operating principle

4.5.2.1 When spool is in neutral position

[Main circuit]
● When all the spools are in neutral position,
working oil supplied from the hydraulic
pump (Front) flows in through pump port
P1 and is introduced into the main pas-
sage (1). It passes the neutral bypass (2)
(neutral M-shaped spool mechanism) of
the spools of straight travel (308), L. travel
(301), boom 1 (303), bucket (304) and arm
2 (306), and fl ows back into the working oil
tank via return port (R1).
4-46
SY195/205/215/225C9 Crawler Hydraulic Excavator
Shop Manual - June 2013
https://www.tractormanualpdf.info/
● Working oil supplied from the hydraulic
pump (Rear) fl ows in through pump port P2
and is introduced into the main passage
(3). It passes the neutral bypass (2) (neutral
M-shaped spool mechanism) of the spools
of R travel (301), swing (305), boom con-
fl uence (boom 2: 307), option (309), arm 1
(302), and flows back into the working oil
tank via return port (R1).