SANY Crawler Hydraulic Excavator (SY195C9, SY205C9, SY215C9, SY225C9). Shop Manual (2013) - page 7
Structure and Function
B
6
13
7
8
1
18
18
4
A
5
17
ZX215-1002020
Function
Ɣ The torque of the engine is transmitted
to the pump shaft (1), and drives cylinder
block (7) to rotate. At the same time, nine
plungers (6) slide along the thrust plate (8).
Plunger (6) moves back and forth inside
cylinder block (7) and pressurized oil is
sucked and discharged alternatively.
Ɣ It is possible to change the discharge
amount by changing the swash plate an-
gle.
4-30
Structure and Function
Structure
Ɣ
Cylinder block (7) is supported to shaft (1)
by spline (17).
Ɣ
Shaft (1) is supported by front and rear
bearings (18).
Ɣ
Tip of plunger (6) is shaped as a concave
ball and slipper (5) is caulked to it to form
one unit.
Ɣ
Plunger (6) and slipper (5) constitute the
spherical bearing.
Ɣ
Swash plate (4) has flat surface (A), and
slipper (5) is always pressed against this
surface while sliding in a circular move-
ment.
Ɣ
Swash plate (4) conducts high pressure oil
to cylinder surface (B), and forms a static
pressure bearing when it slides.
Ɣ
Plunger (6) carries out relative movement
in the axial direction inside each cylinder
chamber of cylinder block (7).
Ɣ
Cylinder block (7) seals the pressurized oil
to thrust plate (8) and carries out relative
rotation.
Ɣ
This surface is designed so that the oil
pressure balance is maintained at a suit-
able level.
Ɣ
The oil inside the respective cylinder cham-
bers of cylinder block (7) is sucked in and
discharged through thrust plate (8).
4-31
Structure and Function
Operation of pump
Ɣ Cylinder block (7) rotates together with
1
4
5
7
A
shaft (1), and slipper (5) slides on flat sur-
face (A).
Ɣ When this happens, swash plate (4) moves
along cylindrical surface (B), so angle (a)
between central line (X) of swash plate (4)
a
and the axial direction of cylinder block (7)
X
changes.
B
ZX215-1002021
Ɣ (a) is named the swash plate angle.
Ɣ
With central line (X) of swash plate (4) at
4
6
a swash plate angle (a) in relation to the
5
A
F
axial direction of cylinder block (7), flat sur-
face (A) acts as a cam in relation to slipper
(5).
Ɣ
In this way, plunger (6) slides on the in-
side of cylinder block (7), so a difference
a
between volumes (E) and (F) is created
X
E
inside cylinder block (7).
7
ZX215-1002022
Ɣ
A single plunger sucks and discharges the
oil by the amount (F) - (E).
Ɣ
As cylinder block (7) rotates and the vol-
ume of chamber (E) becomes smaller, the
pressurized oil is discharged.
Ɣ
On the other hand, the volume of chamber
(F) grows larger and, in this process, the
oil is sucked.
Ɣ
As central line (X) of swash plate (4) over-
laps the axial direction of cylinder block (7)
F
(swash plate angle (a) = 0), the difference
between volumes (E) and (F) inside cylin-
der block (7)becomes 0.
Ɣ
Suction and discharging of pressurized
oil is not carried out in this state. Namely
pumping action is not performed. (In real-
E
ity, however, the swash plate angle is not
4
7
set to 0)
ZX215-1002023
4-32
Structure and Function
Control of delivery
Ɣ If swash plate angle (a) becomes larger,
13 16
F
the difference between volumes (E) and
(F) becomes larger and pump delivery (Q)
increases.
Ɣ Piston (13) is used for changing swash
plate angle (a).
Ɣ Piston (13) carries out linear alternating
a
motion under the control of the adjustor.
Ɣ This linear motion is transmitted to swash
plate (4) via drive pin (16). The sliding of
4
E
ZX215-1002024
the swash plate changes the swash plate
angle and changes the discharge amount
of the main pump.
4-33
Structure and Function
4.4.4 Pilot pump
NOTE: For the location of the pilot pump on the machine, see “Hydraulic equipment layout” on
page 4-24.
435
433
710
700
354
351
434
310
355
732
311
312
309
307
308
434
850
466
725
435
361
353
ZX215-1002025
307: Valve stem
361: Body
308: Valve base
433: Screw
309: Retainer
434: Screw
310: Spring
435: screw
311: Adjusting screw
466: Plug
312: Nut
700: Washer
351: Body
710: O-ring
353: Gear shaft
725: O-ring
354: Gear shaft
732: O-ring
355: Filter element
850: Washer
Function
Ɣ The engine actuates the main pump and
the drive shaft of the pilot pump through
the transmission case, and drives the pilot
pump through gear engagement.
4-34
Structure and Function
4.4.5 Regulator
(KR3G-0E11-AV)
NOTE: Both the front pump and the rear pump are equipped with a regulator. For the location of
the hydraulic pump, see “Hydraulic equipment layout” on page 4-24.
SKY5P
079
496
- 17 - S
418
PSV
B
624
627
646
897
415
A
325
408
a
496
924
801
601
755
402
614
466
543
656
407
643
755
A
756
733
631
708
724
545
731
887
611
651 652 733
541
A-A
(KDRDE5K) PSV
Tightening torTue
Name plate and s/n
Tightening torTue
Part No.
Thread size
a
Nm
Type
402, 407
M6
12
408
415
M8
29
s/n
G-OE11-V
418
M5
6.9
466
G1/4
16
496
NPTF1/16
8.8
614
G1/4
36
Direction B
801
M10
29
Hydraulic schematic diagram
ZX225-1102002
4-35
Structure and Function
Category
Part No.
Part name
Q’ty
Remark
C
924
Hexagon socket head locating screw
1
/
897
Pin
1
/
887
Pin
1
D
801
Hexagon nut
1
JIS B 1181 N-M10
D
756
O-ring
2
D
755
O-ring
2
D
733
O-ring
2
D
731
O-ring
1
D
724
O-ring
5
D
708
O-ring
1
/
656
Cover plate
1
/
652
Spool valve
1
/
651
Sleeve
1
/
646
Guide spring
1
/
643
Pilot plunger
1
/
631
Pf pilot sleeve
1
/
627
Adjusting roller
1
/
624
Spring seat
1
/
614
Plug
1
/
611
Feedback lever
1
/
601
Casing
1
/
545
Ball
2
/
543
Stopper
2
/
541
Valve seat
2
C
496
Embedded plug
9
C
466
VIP plug
1
D
418
Hex socket head bolt
2
JIS B 1176 M5-12
D
415
Hex socket head bolt
6
JIS B 1176 M8-50
D
408
Hex socket head bolt
1
JIS B 1176 M6-40
D
407
Hex socket head bolt
4
JIS B 1176 M6-30
D
402
Hex socket head bolt
4
JIS B 1176 M6-16
/
325
Valve body
1
B
079
Sol proportional reducing valve
1
B
—
Regulator assembly
1
B:
Assembly obtainable at the dealers (individual parts not purchasable)
/:
Individual components included in assemblies of category B
C:
Parts obtainable at the dealers
D:
Parts obtainable on the market
4-36
Structure and Function
Function
Ɣ The regulator controls the pump discharge
PSV
amount according to the command signal
pressure, keeping the driving power of the
pump lower than the engine output.
a
Ɣ Pumps 1 and 2 are both equipped with a
regulator. Key components of the regulator
1
include a solenoid proportional pressure
reducing valve (1), a positive flow regulator
(2), a servo reversing valve (3) and a servo
2
piston (4). The regulator opens and shuts
the oil circuit of the servo piston (3) and
changes the tilting angle of the hydraulic
tank according to various command signal
3
pressure so as to control the pump dis-
4
charge amount.
ZX225-1102003
4.4.5.1 Control mechanism makeup
Current control
Ɣ The inclination (output delivery amount)
of the pump can be controlled freely by
changing of the command current I flow-
ing into the solenoid proportional pressure
reducing valve. This regulator applies posi-
tive flow control (positive control), through
which output delivery amount Q changes
according to the increase of command cur-
rent. Necessary current for corresponding
operation can be input through this control
mechanism. The pump only delivers nec-
essary oil amount and wastes no useless
power.
4-37
Structure and Function
4.4.5.2 Adjustment of the regulator
806
532
548 531
808
954
953
ZX215-1002028
531: Inclination pin
SKY5P
- 17 - S
532: Servo piston
PSV
548: Feedback pin
806: Retaining nut
808: Retaining nut
924
953: Adjusting screw
954: Adjusting screw
Ɣ It is possible to adjust the maximum and
minimum flow by the adjusting screws (953,
ZX225-1102004
954) in the pump block side. Flow control
features can be adjusted with the hexagon
socket head locating screw (924) on the
regulator.
4-38
Structure and Function
Maximum flow adjustment (pump block
side)
Ɣ Loosen the hexagon nut (808), and tighten
(or loosen) hexagon socket head locating
screw (954). No control features except the
maximum flow changes.
Command current I
ZX215-1002033
Minimum flow adjustment (pump block
side)
Ɣ Loosen the hexagon nut (806), and tighten
(or loosen) the hexagon socket head locat-
ing screw (953). Though this action is the
same as the adjustment of maximum flow
and all the other control features do not
change, power required under maximum
output pressure (overflow) is likely to in-
crease if over-tightened. Be careful in this
case.
Command current I
ZX215-1002034
4-39
Structure and Function
Flow control feature adjustment
Ɣ After hexagon nut (810) is loosened, tight-
en (or loosen) the hexagon socket head lo-
cating screw (924) to carry out adjustment.
When the hexagon socket head locating
screw (924) is being tightened, the control
diagram (as shown) will move to the right.
Command current I
ZX215-1002037
4.4.5.3 Operation
Flow control
Ɣ The output flow of the pump can be con-
trolled by the command current I, as
shown.
Command current I
ZX215-1002030
4-40
Structure and Function
Action of increasing flow rate
Ɣ
When command current I increases, the
079
solenoid proportional pressure reducing
651
652
valve secondary pressure P2 will increase,
627 646
and the spool valve (652) will move the
643
P1
801
right with the help of the guide piston (643).
924
When a relative balance between the right-
611
532
ward hydraulic force and the spring force
808
A
806
of guide spring (646) is achieved, spool
954
953
valve (652) stops moving.
P1
Ɣ
As spool valve (652) moves to the right,
because port cl and tank port are intercon-
Tilt angle large
nected, pressure of the large diameter
ZX225-1102005
portion of the servo piston is released and
servo piston (532) moves to the left via the
output pressure P1 in the shall diameter
portion. The inclination becomes larger.
PSV
Ɣ
Since feedback lever (611) is integrated
with the servo piston and valve sleeve
(651), if servo piston (632) moves to the
a
left, feedback lever swings with point A as
the pivot. In this way, valve sleeve moves
to the right.
Ɣ
Through this movement, the opening por-
tion between the spool and the valve block
is closed slowly. The servo piston stops
moving when the opening portion is com-
pletely closed.
ZX225-1102006
4-41
Structure and Function
Action of reducing flow rate
Ɣ When command current I decreases, the
079
solenoid proportional pressure reducing
651 652
valve secondary pressure P2 will decrease,
627 646
and guide piston (643) will move to the left.
643
801
P1
However, as spool valve (652) moves, out-
924
611
put pressure P1 is introduced into the large
532
diameter chamber of the servo piston via
808
A
806
954
the port cl. On the other hand, output pres-
953
sure P1 is introduced into the small diam-
P1
eter chamber of the servo piston and servo
piston moves to the right via are difference.
Tilt angle small
The inclination becomes smaller.
ZX225-1102007
Ɣ As servo piston (532) moves to the right,
the feedback lever swings with point A as
the pivot and the valve sleeve moves to the
PSV
left. Through this movement, the opening
portion between the spool and the valve
block is slowly closed. The servo piston
a
stops moving when the opening portion is
completely closed.
ZX225-1102008
Adjustment value of the regulator
Type of regulator
KR3G-0E11-AV
Rotating speed (min-1)
2050
Adjusting screw (954) screw-in (rotation)
+1/4
Adjustment of max. flow
Flow rate change (L/min)
-5.9
Adjusting screw (953) screw-in (rotation)
+1/4
Adjustment of min. flow
Flow rate change (L/min)
+4.7
4-42
Structure and Function
4.5 Hydraulic System, Part 2
4.5.1 Control valve
NOTE: For the location of the control valve on the machine, see “Hydraulic equipment layout” on
page 4-24.
(XAo)
XBp2
XAa1
BaR
XAa2
BoR
BkR
Psp
BbR
XAb1
Dr2
XBtr
XBtL
XAs
(PTa)
XBtr
Dr3
PnA2
Dr6
Dr7
Pns
Bs
Btr
As
Atr
Pz
AtL
PX
PG
PbL
TRAVEL STRAIGHT
MR
TRAVEL RIGHT
Py
XAtr
TRAVEL LEFT
SWING
XAtL
BtL
Dr1
XBs
BOOM1
SWING PRIORITY
BOOM2
Bb(Rod)
XBb1
XAb2
AbR
BUCKET
OPTION
PCk
(XBo)
XAk
AkR
(Bo)
ARM2
ARM1
XBa2
XBk
Dr3
XBa1
AoR
(BYPASS CUT 1)
Bk(Rod)
PCV1
(XBp1)
DR3
AaR
R2
PaL
Ba(Head)
Aa(Rod) Ak(Head) Ab(Head)
(Ao)
P2
P1
R1
R1
ZX225-1102009
4-43
Structure and Function
XAtr : R. travel (reverse) pilot port
XBp2:
Bypass cut spool pilot port (P2 side)
XBtr : R. travel (forward) pilot port
XAb2:
Boom confluence (UP) pilot pressure
(XAo): (Option pilot port)
Psp:
Swing priority pilot port
(XBo): (Option pilot port)
R1:
Return port
XAk:
Bucket (DIG) pilot port
R2:
Oil feed port
XBk:
Bucket (DUMP) pilot port
Atr:
R. travel motor port (reverse)
XAb1:
Boom 1 (UP) pilot port
Btr:
R. travel motor port (forward)
XBb1:
Boom 2 (DOWN) pilot port
(Ao):
Option
XAa2:
Arm 2 (OUT) pilot port
(Bo):
Option
XBa2:
Arm 2 (IN) pilot port
Ak:
Bucket cylinder head end port (DIG)
XAtL:
L. travel (reverse) pilot port
Bk:
Bucket cylinder rod end port (DUMP)
XBtL:
L. travel (forward) pilot port
Ab:
Boom cylinder head end port (UP)
XAs:
Swing (left) pilot port
Bb:
Boom cylinder rod end port (DOWN)
XBs:
Swing (right) pilot port
AtL:
L. travel motor port (reverse)
XAa1:
Arm 1 (OUT) pilot port
BtL:
L. travel motor port (forward)
XBa:
Arm 1 (IN) pilot port
As:
Swing motor port (left swing)
Dr1:
Drain port
Bs:
Swing motor port (right swing)
Px:
Work equipment signal port
Aa:
Arm cylinder rod end port (OUT)
Py:
Travel signal port
Ba:
Arm cylinder head end port (IN)
Pz:
Main relief valve boosting pressure
P1:
Pump port (P1 side)
PG:
Pilot pressure resource port
P2:
Pump port (P2 side)
Pns:
Swing logic control valve pilot port
MR:
Main relief valve
PCK:
Bucket (DIG) stroke limit pilot port
AR:
Arm regeneration check valve
PnA2:
Arm 2 logic control valve pilot port
AbR:
Port relief valve
Dr2:
Drain port
BbR:
Port relief valve
Dr3:
Drain port
AkR:
Port relief valve
Dr6:
Drain port
BkR:
Port relief valve
Dr7:
Drain port
AoR:
Port relief valve
Pal:
Lock valve pilot port (arm rod end)
BoR:
Port relief valve
PbL:
Lock valve pilot port (boom head end)
AaR:
Port relief valve
(XBp1):Bypass cut spool pilot port (P1 side)
BaR:
Port relief valve
NOTE: For more technical information about the control valve, see “Control valve” on page 3-6.
4-44
Structure and Function
Hydraulic circuit diagram (with bucket confluence function)
P2
(P3)
R1
(P0)
P1
PG
d1
d2
d3
ĭ0.7
ĭ0.7
ĭ0.7
MR
CMR2
CMR1
XBtr
Pz
TRAVEL R
(PTa)
TRAVEL
XAtr
STRAIGHT
Px
Atr
CPG
Btr
CP1
Dr2
Dr6
LCs
Py
XBs
SWING
XBtl
4-ĭ2.1
TRAVEL L
XAs
XAtl
As
Btl
Bs
Atl
Pns
C2
Dr1
SWING
PRIORITYPsp
LCb
XBb1
XAb1
BOOM1
BOOM2XAb2
Bb
AbR
(ROD)
BbR
CCb
Ab
(HEAD)
HVb
PbL
LCk
LCo
PCk
(XBo)
XBk
BUCKET
OPTION(XAo)
XAk
AoR
(Ao)
BkR
(ROD)
Bk
(Bo)
Ak
AkR
(HEAD)
BoR
AR
PnA2
Dr3
Dr7
LCa
LCAT2
2-ĭ1.0
LCAP2
2-ĭ2.0
XAa1
XBa2
ARM2
ARM1
XBa1
XAa2
(HEAD)
AaR
Ba
BaR
Aa
CCo
(ROD)
HVa
CCk
PaL
BYPASS(XBp1)
CUT
R2
XBp2
(P5)
ZX225-1102010
4-45
Structure and Function
4.5.2 Operating principle
4.5.2.1 When spool is in neutral position
[Main circuit]
Ɣ When all the spools are in neutral position,
Ɣ Working oil supplied from the hydraulic
working oil supplied from the hydraulic
pump (Rear) flows in through pump port P2
pump (Front) flows in through pump port
and is introduced into the main passage
P1 and is introduced into the main pas-
(3). It passes the neutral bypass (2) (neutral
sage (1). It passes the neutral bypass (2)
M-shaped spool mechanism) of the spools
(neutral M-shaped spool mechanism) of
of R travel (301), swing (305), boom con-
the spools of straight travel (308), L. travel
fluence (boom 2: 307), option (309), arm 1
(301), boom 1 (303), bucket (304) and arm
(302), and flows back into the working oil
2 (306), and flows back into the working oil
tank via return port (R1).
tank via return port (R1).
4-46
Structure and Function
(1)
(2)
(PTa)
XAtL
XBtL
XBb1
XAbL
XAk
PCk
X8k
XBa2
XAa2
CCo CCk
P2
(P3)
R1
(3)
(2)
XBtr
XAtr
XAs
XBs
Psp
XAb2
(XAo)
(XBo)
XAa1
XBa1
XBp2
(XBp1)
ZX225-1102011
4-47
Structure and Function
4.5.2.2 Travel
[Pilot circuit]
Ɣ Likewise, when pressure at port XBtr for
the right travel spool (301) rises, neutral
Ɣ When the left or right travel spool is
bypass (2) at arm 1 side is closed, and
switched, the side bypass circuit is closed
working oil supplied from the hydraulic
and pressure at port Py (travel signal port)
pump (rear) is introduced into the right
rises.
travel motor via port Btr.
[Main circuit]
Ɣ On the other hand, return oil from the left
and right travel motor passes the left (right)
Ɣ When pressure at pilot port XBtL for left
travel spool via port Atl (Atr), and returns to
travel spool (301) rises, neutral bypass (2)
working oil tank via return port (R1).
at boom 1 side is closed, and working oil
supplied from the hydraulic pump (front) is
Ɣ The principle is the same when travel on
introduced into the left travel motor via port
the opposite side is operated (when pres-
Btl.
sure at pilot port XAtr and XAtl rises).
XAtr
XBtr
Atr
Btr
Travel motor
ZX225-1102012
4-48
Structure and Function
4.5.2.3 Arm
(1) Arm OUT
[Pilot circuit]
Ɣ
On the other hand, working oil from port
P1 is introduced into neutral bypass (2) via
Ɣ When the arm 2 spool (306) is switched,
main passage (1). Neutral bypass is cut off
the side path is closed and pressure at port
by switching the arm 2 spool (306). There-
Px (work equipment signal port) rises.
fore, working oil in the parallel passage
pushes open the logic cone valve (256-101)
[Main circuit]
of the arm 2 logic valve GP, and working oil
Ɣ When arm OUT is operated, pilot pres-
from neutral bypass pushes open the cone
sure oil is supplied into port XAa1 and port
valve (511) of the check valve and flows
XAa2. When pilot pressure oil is applied at
into the arm 2 spool (306) via the U pas-
the two sides of port XAa1 and port XAa2,
sage. Then, it merges with port As via the
arm 1 spool and arm 2 spool are switched
inner passage of arm 2 spool (306) and is
to the left as shown in the illustration. As
supplied into the arm cylinder rod end (R).
a result, working oil from P2 is introduced
Ɣ
Return oil from the arm cylinder head end
into neutral bypass (2) via main passage
(H) via port Ba flows into the tank circuit of
(3). Neutral bypass is cut off by switching
arm 1 and arm 2, and returns to working oil
arm 1 spool (302). Therefore, working oil
tank via tank port (R1).
in the parallel passage pushes open the
cone valve (511) of the check valve, and
flows into the arm 1 spool (302) via the U
passage. Then, it flows into the periphery
of arm 1 spool (302) and arm 2 spool (306)
and is supplied into the arm cylinder rod
end (R) via port As.
4-49