Section III Basic structure of H12 excavators mechanical system
1
Power system
H12 excavator is equipped with single-cylinder air-cooling diesel/gasoline engine, include KOOP/CHANGCHAI or
BRIGGS & STRATTON Engine. The KUBOTA engine is three-cylinder water-cooling engine, which is made by Japan.
2
Drive system
H12 excavator's drive system could transfer the output power from engine through the hydraulic system to work
equipment, swing mechanism and traveling mechanism.
3
Swing mechanism
Swing mechanism could turn the work equipment and upper rotary leftwards and rightwards, so as to do the
excavating and the unloading. H12 excavator's swing mechanism has to fix the rotary table onto frame and
has it swing flexibly, without any inclining risk. Therefore, H12 excavator is equipped with a slewing
support (supports) and a slewing drive (power of turntable slewing), which are called by a joint name as
swing mechanism.
3.1
Slewing support
H12 excavator has its rotary table supported with a rolling bearing, realizing the swinging of upper rotary.
3.2
Rotary drive
H12 excavator adopts the direct drive type. Namely, the output shaft of low-speed high-torque hydraulic
motor is mounted with a driving pinion which meshes with the slewing gear ring.
4
Traveling mechanism
Traveling mechanism supports the complete weight of excavator and drives it to run.
H12 excavator has the crawler traveling mechanism similar to other crawlers, with one hydraulic motor drives one
track. This excavator adopts low-speed high-torque motor. When two hydraulic motors run in the same direction,
this machine goes straightly forward; when one motor is supplied with oil and the other is braked, excavator steers
around the braked track; when two motors runs reversely, excavator rotates as circle.
Each part of traveling mechanism is mounted on integral traveling frame. The pressure oil from hydraulic pump
goes through the multi-way directional valve and the central swing joint into the hydraulic traveling motor that
changes the pressure energy into output torque that then goes to sprocket, driving excavator to run.
H12 excavator’s sprockets are integral castings and able to correctly engage with track, featuring balance drive.
Sprockets located at rear part of excavator, shortening the tensioner part and relieving the track abrasion, wear
and power consumption. Each track is equipped with a tensioner, adjusting the tracking tension and reducing
the track vibration noise, abrasion, wear and power loss.
5
Work equipment
The hydraulic excavator could install multiple working equipment, 200mm bucket and ripper are most popular.
The boom, arm and bucket are articulated with each other, as shown in figure and swing around their articulated points
respectively with aid of the hydraulic cylinder, to finish the excavating,lifting and unloading.
5.1
Boom
As the main component of backhoe work equipment, the integrated skewed boom is adopted on H12
excavator.
Being of the most popular type at present, skewed boom could allow excavator to dip deeper and to lower the
unloading depth, satisfying the backhoe requirements.
