Hyundai Excavator R450LC-7. Service and repair manual - page 3

1-22

Category

Applications

Precautions

A

B

C

Rocky ground, 
river beds, 
normal soil

Normal soil,
soft ground

Extremely soft gound
(Swampy ground)

Travel at low speed on rough ground with large obstacles such as

boulders or fallen trees

These shoes cannot be used on rough ground with large obstacles such

as boulders or fallen trees

Travel at high speed only on flat ground

Travel slowly at low speed if it is impossible to avoid going over

obstacles

Use the shoes only in the conditions that the machine sinks and it is

impossible to use the shoes of category A or B

These shoes cannot be used on rough ground with large obstacles such

as boulders or fallen trees

Travel at high speed only on flat ground

Travel slowly at low speed if it is impossible to avoid going over

obstacles

·

·

·
·

·

·

·
·

※

T

T

able 2

SECTION  2  STRUCTURE AND FUNCTION

Group   1  Pump Device - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 2-1

Group   2  Main Control Valve - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 2-21

Group   3  Swing Device - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 2-46

Group   4  Travel Deviceb - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 2-57

Group   5  RCV Lever - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 2-64

Group   6  RCV Pedal - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 2-71

2-3

04

Gear pump

080 Proportional reducing 

valve assy

111 Drive shaft
113 Driven shaft
123 Roller bearing
124 Needle bearing
126 Spacer
127 Spacer
128 Bearing spacer
129 Bearing spacer
130 Booster
131 Booster cover
141 Cylinder block
151 Piston
152 Shoe
153 Plate
156 Bushing
157 Cylinder spring
171 Front casing
191 Drive gear
192 Driven gear
211 Shoe plate
212 Swash plate
214 Tilting bushing
251 Swash plate support
261 Front cover

262 Cover
271 Pump casing
312 Valve cover
313 Valve plate(R)
314 Valve plate(L)
405 Hexagon socket bolt
406 Hexagon socket bolt
408 Hexagon socket bolt
409 Hexagon socket bolt
410 Hexagon socket bolt
411 Hexagon socket bolt
412 Hexagon socket bolt
413 Hexagon socket bolt
467 Plug
469 Plug
490 Plug
491 Plug
492 Restrictor
493 Plug
531 Tilting pin
532 Servo piston
534 Stopper(L)
535 Stopper(S)
536 Servo cover
541 Seat
543 Stopper
545 Steel ball

548 Feed back pin
702 O-ring
709 O-ring
711 O-ring
712 O-ring
724 O-ring
725 O-ring
726 O-ring
728 O-ring
732 O-ring
752 Seat packing
774 Oil seal
789 Back up ring
792 Back up ring
806 Nut
807 Nut
823 Snap ring
824 Snap ring
825 Snap ring
827 Snap ring
828 Snap ring
885 Valve plate pin
886 Spring pin
888 Pin
901 Eye bolt
953 Set screw
954 Set screw

2-4

MAIN PUMP(2/2)

079

Proportional reducing valve

325

Valve casing 

407

Hexagon screw

408

Hexagon screw

467

Plug

490

Plug

724

O-ring

725

O-ring

732

O-ring

45070MP04

2-6

REGULATOR(2/2)

412

Hexagon socket screw

413

Hexagon socket screw

436

Hexagon socket screw

438

Hexagon socket screw

496

Plug

601

Casing

611

Feed back lever

612

Lever(1)

613

Lever(2)

614

Center plug

615

Adjust plug

621

Compensator piston

622

Piston case

623

Compensator rod

624

Spring seat(C)

625

Outer spring

626

Inner spring

627

Adjust stem(C)

628

Adjust screw(C)

629

Cover(C)

630

Lock nut

631

Sleeve, pf

641

Pilot cover

642

Adjust screw(QMC)

643

Pilot piston

644

Spring seat(Q)

645

Adjust stem(Q)

646

Pilot spring

647

Stopper

648

Piston(QMC)

651

Sleeve

652

Spool

653

Spring seat

654

Return spring

655

Set spring

656

Block cover

708

O-ring

722

O-ring

723

O-ring

724

O-ring

725

O-ring

728

O-ring

730

O-ring

732

O-ring

733

O-ring

734

O-ring

735

O-ring

755

O-ring

756

O-ring

763

O-ring

801

Nut

814

Snap ring

836

Snap ring

858

Snap ring

874

Spring pin

875

Pin

887

Pin

897

Pin

898

Pin

924

Set screw

925

Adjust screw(QI)

45070RG02

2-7

GEAR PUMP

3)

307

Poppet

308

Seat

309

Spring seat

310

Spring

311

Adjusting screw

312

Lock nut

351

Gear case

353

Drive gear

354

Driven gear

355

Filter

361

Front case

433

Flange socket

434

Flange socket

435

Flange socket

466

Plug

700

Ring

709

O-ring

725

O-ring

732

O-ring

850

Snap ring

45070RG03

2-8

Rotary group
The rotary group consists of drive shaft
(F)(111), cylinder block(141), piston
shoes(151,152), set plate(153), spherical
bush(156) and cylinder spring(157).   
The drive shaft is supported by
bearing(123,124) at its both ends.
The shoe is caulked to the piston to from
a spherical coupling.   It has a pocket to
relieve thrust force generated by loading
pressure and the take hydraulic balance
so that it slides lightly over the shoe
plate(211).   The sub group composed by
a piston and a shoe is pressed against the
shoe plate by the action of the cylinder
spring via a retainer and a spherical bush.
Similarly, the cylinder block is pressed
against valve plate(313) by the action of
the cylinder spring.

Swash plate group
The swash plate group consists of swash
plate(212), shoe plate(211), swash plate
support(251), tilting bush(214), tilting
pin(531) and servo piston(532).
The swash plate is a cylindrical  part
formed on the opposite side of the sliding
surface of the shoe and is supported by
the swash support.
If the servo piston moves to the right and
left as hydraulic force controlled by the
regulator is admitted to hydraulic chamber
located on both sides of the servo piston,
the swash plate slides over the swash
plate support via the spherical part of the
tilting pin to change the tilting angle(

α

)

2

2

. FUNCTION

MAIN PUMP
The pumps may classified roughly into the rotary group performing a rotary motion and working as
the major part of the whole pump function: the swash plate group that varies the delivery rates: and
the valve cover group that changes over oil suction and discharge.

1)

(1) 

(2)

45070RG04

45070RG05

2-7 (210-7)

α

α

2-9

Valve cover group
The valve cover group consists of valve
cover(312), valve plate(313, 314),
booster(130), boost cover(131) and valve
plate pin(885).
The valve plate having two melon-shaped
ports is fixed to the valve cover and feeds
and collects oil to and from the cylinder
cover.
The oil changed over by the valve plate is
connected to an external pipeline by way
of the valve cover.
Now, if the drive shaft is driven by a prime
mover(electric motor, engine, etc), it
rotates the cylinder block via a spline
linkage at the same time.  If the swash
plate is tilted as in Fig(previous page) the
pistons arranged in the cylinder block
make a reciprocating motion with respect
to the cylinder block, while they revolve
with the cylinder block.
If you pay attention to a single piston, it
performs a motion away from the valve
plate(oil sucking process) within 180
degrees, and makes a motion towards the
valve plate(or oil discharging process) in
the rest of 180 degrees.  When the swash
plate has a tilting angle of zero, the piston
makes no stroke and discharges no oil.

(3)

45070RG06