SANY Crawler Hydraulic Excavator SY215CLC (CUMMINS QSB6.7 engine). Shop Manual

Structure and Function

SY215C

4-28

4.4.3

Hydraulic pump

Type: K3V112DTP1N9R

ZX215-1002018

a1
{36N·m}

a2
{36N·m}

a5
{16N·m}

a4
{36N·m}

PH1

PH2

Clockwise

Psv2

DR2{170N·m}

DR4{170N·m}

DR3{170N·m}

DR1{170N·m}

a3
{36N·m}

Structure and Function

SY215C

4-29

a1: F. pump main pressure detection port

a2: R. pump main pressure detection port

a3: F. pump regulator pressure detection port

a4: Adjustor control pressure detection port

a5: Pilot gear pump output pressure detection
port

PH1: F. pump pressure sensor assembly port

PH2: R. pump pressure sensor assembly port

A1: F. pump delivery port

A2: R. pump delivery port

A3: Pilot gear pump delivery port

Psv1: F. pump regulator control port

Psv2: R. pump regulator control port

Dr1: F. pump drain plug

Dr2: R. pump drain plug

Dr3: Air bleeder

Dr4: Drain plug

B1: Pump suction port

B3: Pilot gear pump oil suction port

1: Front pump

2: Rear pump

3: Pilot gear pump

4: Front pump regulator

5: Rear pump regulator

Outline

●

This pump consists of 2 variable capacity swash plate plunger pumps, 2 regulators, and 1 pi-
lot gear pump.

Structure and Function

SY215C

4-32

Structure

●

Cylinder block (7) is supported to shaft (1)
by spline (17).

●

Shaft (1) is supported by front and rear
bearings (18).

●

Tip of plunger (6) is shaped as a concave
ball and slipper (5) is caulked to it to form
one unit.

●

Plunger (6) and slipper (5) constitute the
spherical bearing.

●

Swash plate (4) has flat surface (A), and
slipper (5) is always pressed against this
surface while sliding in a circular move-
ment.

●

Swash plate (4) conducts high pressure oil
to cylinder surface (B), and forms a static
pressure bearing when it slides.

●

Plunger (6) carries out relative movement
in the axial direction inside each cylinder
chamber of cylinder block (7).

●

Cylinder block (7) seals the pressurized oil
to thrust plate (8) and carries out relative
rotation.

●

This surface is designed so that the oil
pressure balance is maintained at a suit-
able level.

●

The oil inside the respective cylinder cham-
bers of cylinder block (7) is sucked in and
discharged through thrust plate (8).

Structure and Function

SY215C

4-33

Operation of pump

●

Cylinder block (7) rotates together with
shaft (1), and slipper (5) slides on

at sur-

face (A).

●

When this happens, swash plate (4) moves
along cylindrical surface (B), so angle (a)
between central line (X) of swash plate (4)
and the axial direction of cylinder block (7)
changes.

●

(a) is named the swash plate angle.

●

With central line (X) of swash plate (4) at
a swash plate angle (a) in relation to the
axial direction of cylinder block (7),

at sur-

face (A) acts as a cam in relation to slipper
(5).

●

In this way, plunger (6) slides on the in-
side of cylinder block (7), so a difference
between volumes (E) and (F) is created
inside cylinder block (7).

●

A single plunger sucks and discharges the
oil by the amount (F) – (E).

●

As cylinder block (7) rotates and the vol-
ume of chamber (E) becomes smaller, the
pressurized oil is discharged.

●

On the other hand, the volume of chamber
(F) grows larger and, in this process, the
oil is sucked.

●

As central line (X) of swash plate (4) over-
laps the axial direction of cylinder block (7)
(swash plate angle (a) = 0), the difference
between volumes (E) and (F) inside cylin-
der block (7)becomes 0.

●

Suction and discharging of pressurized
oil is not carried out in this state. Namely
pumping action is not performed. (In real-
ity, however, the swash plate angle is not
set to 0)

ZX215-1002021

ZX215-1002022

ZX215-1002023

Structure and Function

SY215C

4-35

4.4.4

Pilot pump

ZX215-1002025

710

435

433

700

434

355

354

310

351

732

311

312

309

307

308

434 850

466

725

435

361

353

307: Valve stem
308: Valve base
309: Retainer
310: Spring
311: Adjusting screw
312: Nut
351: Body
353: Gear shaft
354: Gear shaft
355: Filter element

361: Body
433: Screw
434: Screw
435: screw
466: Plug
700: Washer
710: O-ring
725: O-ring
732: O-ring
850: Washer

Function

●

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.

Structure and Function

SY215C

4-36

4.4.5

Regulator (KR3G-0E11-AV)

G-OE11-V

Type

s/n

Name plate and s/n

Tightening torque

(KDRDE5K)

Hydraulic schematic diagram

KDRDE5C-1

079

325

496

408

755 466

407

643

651

652

733

631

731

624

627

A-A

646

897

924

801

402

656

614

755

708

611

733

724

887

SKY5P

- 17 - S

Direction B

ZX225-1102002

418

415

496

601

543

756

545

541

Part No.

Thread size

Tightening torque

N•m

402, 407

408

415

418

466

496

614

801

G1/4

M10

NPTF1/16

6.9

8.8

Structure and Function

SY215C

4-37

Category

Part No.

Part name

Q’ty

Remark

924

Hexagon socket head locating screw

897

887

801

Hexagon nut

JIS B 1181 N-M10

756

O-ring

755

O-ring

733

O-ring

731

O-ring

724

O-ring

708

O-ring

656

Cover plate

652

Spool valve

651

Sleeve

646

Guide spring

643

Pilot plunger

631

Pf pilot sleeve

627

Adjusting wheel

624

Spring seat

614

Plug

611

Feedback lever

601

Casing

545

Ball

543

Stopper

541

Valve seat

496

Embedded plug

466

VIP plug

418

Hex socket head bolt

JIS B 1176 M5-12

415

Hex socket head bolt

JIS B 1176 M8-50

408

Hex socket head bolt

JIS B 1176 M6-40

407

Hex socket head bolt

JIS B 1176 M6-30

402

Hex socket head bolt

JIS B 1176 M6-16

325

Valve body

079

Sol proportional reducing valve

—

Regulator assembly

Assembly obtainable at the dealers (individual parts not purchasable)

Individual components included in assemblies of category B

Parts obtainable at the dealers

Parts obtainable on the market

Structure and Function

SY215C

4-38

●

The regulator controls the pump discharge
amount according to the command signal
pressure, keeping the driving power of the
pump lower than the engine output.

●

Pumps 1 and 2 are both equipped with a
regulator. Key components of the regulator
include a solenoid proportional pressure
reducing valve (1), a positive

ow regulator

(2), a servo reversing valve (3) and a servo
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
pressure so as to control the pump dis-
charge amount.

Function

4.4.5.1 Control mechanism makeup

Current control

●

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

ow 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.

ZX225-1102003

Structure and Function

SY215C

4-39

4.4.5.2 Adjustment of the regulator

531: Inclination pin

532: Servo piston

548: Feedback pin

806: Retaining nut

808: Retaining nut

953: Adjusting screw

954: Adjusting screw

●

It is possible to adjust the maximum and
minimum

ow by the adjusting screws (953,

954) in the pump block side. Flow control
features can be adjusted with the hexagon
socket head locating screw (924) on the
regulator.

ZX215-1002028

953

806

532

548 531

808

954

KDRDE5C-1

924

SKY5P
- 17 - S

ZX225-1102004

Structure and Function

SY215C

4-40

Maximum flow adjustment (pump block
side)

●

Loosen the hexagon nut (808), and tighten
(or loosen) hexagon socket head locating
screw (954). No control features except the
maximum

ow changes.

Minimum flow adjustment (pump block
side)

●

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

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.

ZX215-1002033

Output flow Q

Command current I

ZX215-1002034

Output flow Q

Command current I

ZX215-1002037

Output flow Q

Command current I

Flow control feature adjustment

●

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.

Structure and Function

SY215C

4-41

4.4.5.3 Operation

Flow control

●

The output flow of the pump can be con-
trolled by the command current I, as
shown.

ZX215-1002030

Output flow Q

Command current I

Action of increasing fl ow rate

●

When command current I increases, the
solenoid proportional pressure reducing
valve secondary pressure P2 will increase,
and the spool valve (652) will move the
right with the help of the guide piston (643).
When a relative balance between the right-
ward hydraulic force and the spring force
of guide spring (646) is achieved, spool
valve (652) stops moving.

●

As spool valve (652) moves to the right,
because port cl and tank port are intercon-
nected, pressure of the large diameter
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.

●

Since feedback lever (611) is integrated
with the servo piston and valve sleeve
(651), if servo piston (632) moves to the
left, feedback lever swings with point A as
the pivot. In this way, valve sleeve moves
to the right.

●

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.

Tilt angle large

808
954

643

079

652

651

627 646

801

924
611

532

806
953

ZX225-1102005

ZX225-1102006

Structure and Function

SY215C

4-42

Action of reducing fl ow rate

●

When command current I decreases, the
solenoid proportional pressure reducing
valve secondary pressure P2 will decrease,
and guide piston (643) will move to the left.
However, as spool valve (652) moves, out-
put pressure P1 is introduced into the large
diameter chamber of the servo piston via
the port cl. On the other hand, output pres-
sure P1 is introduced into the small diam-
eter chamber of the servo piston and servo
piston moves to the right via are difference.
The inclination becomes smaller.

●

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
left. Through this movement, the opening
portion between the spool and the valve
block is slowly closed. The servo piston
stops moving when the opening portion is
completely closed.

Tilt angle small

808
954

643

079

652

651

627 646

801
924
611

532

806
953

ZX225-1102007

ZX225-1102008

SANY Crawler Hydraulic Excavator SY215CLC (CUMMINS QSB6.7 engine). Shop Manual - page 8