6
Undercarriage
Advanced Resilient Equalized
Undercarriage (REU)
The Komatsu X-type bogie resilient
equalized undercarriage (REU) performs
independent see-saw movements. Tremen-
dous traction can be achieved even on
uneven ground, because the shoe always
follows the contour of the ground.
A rubber shock absorber is mounted on the
X-type bogie and decreases vibration and
shock. This X-bogie and rubber cushion
provide different absorption characteristics,
depending on the ground surface. When the
machine travels on flat ground, the REU
functions as a conventional rigid under-
carriage. When the machine travels on
uneven ground, the REU maximizes the
suspension effect. The Komatsu REU
system improves traction, component
durability, and operator comfort.
Conventional Undercarriage
There is minimal shoe slippage with the
conventional low drive type undercarriage.
The shoe slip limit has been substantially
raised due to long tracks and large ground
contact area. The large traction force thus
obtained, in combination with high engine
power, results in superb drawbar pull. With
the low center of gravity, dynamic stability
is excellent.
D155A-5
CRAWLER DOZER
Inner
bogie
Rubber
pad
Outer
bogie
Track
roller
Shaft:
Fixed to track
frame
Center
Flexibility
Flexibly grasps ground surface due to Komatsu’s unique track-
roller design for more and better ground contact.
●
Independent X-bogies and rubber pads (cushions) are
incorporated into the track rollers.
Powerful Drawbar Pull for All Kinds of Terrain
The X-bogie and rubber pad provide different suspension
characteristics depending on the ground surface. On flat
ground, REU functions as a conventional rigid undercarriage.
On uneven terrain, the REU maximizes the suspension effect
the shoes always follow the contour of the ground, ensuring
a greater actual ground contact for greatly-improved
drawbar pull.
Frame
Flat Bottom Frame
The pivot shafts and monocoque frames prevent mud build-
up. The design facilitates good maneuverability in muddy
conditions and reduces the chance of hanging up on stumps
or boulders.
On flat ground
On uneven ground
Ensures almost the same traction force as
a conventional rigid undercarriage.
Functions as a conventional rigid
undercarriage.
Track frame
Compared with a rigid type, the actual ground contact
area increases and powerful drawbar pull is ensured
because the track shoes follow the contour of the
ground. Large deformation of the rubber pads
contributes to greater suspension effect.
Seesaw movement is performed
corresponding to ground surface.
Comfortable Ride on Uneven Ground
Minimum Shock in Riding Over Obstacles
On uneven ground, the rubber pad provides four times the
suspension effect.
When riding over obstacles, the height of the machine fall is low.
Flat ground travel
Suspension ef
fect
Rough terrain travel
1
4
Obstacle height B
Fall height
A
Conventional
rigid type
REU
A
B
7
U
NDERCARRIAGE
AND
F
RAME
U
NDERCARRIAGE
AND
F
RAME
