Construction machinery is the hot market this year. The last round of high growth can be traced back to the 4 trillion investment in 2008. This year, on the fast train of new infrastructure construction, the construction machinery market is booming, and the excavator is the most representative product.
Modern hydraulic excavators come in many sizes. The smaller ones are called small or compact excavators. For example, Caterpillar’s smallest small excavator weighs 2060 pounds (930 kg) and weighs 13 horsepower; the largest excavator (developed and produced by Orenstein & Koppel in Germany until Caterpillar was acquired in 2011 under the name ? RH400?), CAT 6090, which weighs more than 2,160,510 pounds (979,990 kg) and 4500 hp.
Hydraulic excavators usually couple engine power to three hydraulic pumps instead of a mechanical transmission system. Two main pumps supply high pressure (up to 5000 psi, 345 bar) oil for the arms, swing motors, crawler motors and accessories, and the third is a low pressure (~700 psi, 48 bar) pump for pilot control. Generally, the 3 pumps used in excavators consist of 2 variable displacement piston pumps and gear pumps. The arrangement of pumps in the excavator unit varies according to the settings of different manufacturers.
The three main parts of an excavator are the landing gear, the housing and the stick (also using the boom). The undercarriage system includes crawlers, crawler frames and final drives. These drives have hydraulic motors and gears to drive each crawler. The undercarriage can also have a blade similar to a bulldozer. The house includes a cab, counterweight, engine, fuel tank and hydraulic tank. The house is fixed on the chassis with a center pin. The high-pressure oil is supplied to the hydraulic motor of the crawler through the hydraulic rotating device on the pin shaft, so that the machine can swing 360° unimpeded, thereby realizing left and right movement. The arm provides up and down movement and further (or digging movement) movement. The arm usually consists of a boom, a stick and a bucket, and there are three joints between them and the house.
The boom is connected to the house and provides up and down movement. It contains several different configurations:
The most common is a single arm, which only moves straight up and down.
Others have steering knuckle arms, which can also move left and right in line with the machine.
Another option is a hinge at the bottom of the boom, which allows it to be hydraulically rotated to 180° independently of the house. However, this usually only applies to compact excavators.
The variable angle boom has an additional joint in the middle of the boom to change the curvature of the boom. These are also called triple boom (TAB) or three-piece boom.
Attached to the end of the boom is a stick (or bucket arm). The stick provides the digging motion required to pull the bucket across the ground. The joystick length is optional, depending on whether a longer joystick or a shorter joystick is required. The most common is the single rod, but there are also telescopic rods.
Before 1990, all excavators had a longer counterweight, which was suspended at the rear of the machine to provide greater digging force and lifting capacity. This becomes troublesome when working in confined areas. In 1993, Yanmar introduced the world's first zero-tail slewing excavator, so that the counterweight can be kept within the width of the crawler when slewing, so it is safer to use in confined spaces. This type of machine is now widely used all over the world.
Two main types of "control" configurations are commonly used in excavators to control the boom and bucket, both of which extend four main excavation controls between two xy joysticks. This requires a skilled operator to control all four functions simultaneously. The most common configuration in the United States is the SAE control configuration, while in other parts of the world, the ISO control configuration is more common. Some manufacturers (such as Takeuchi) allow the operator to choose the control configuration to use.
Excavator accessories
The function of the hydraulic excavator has gone far beyond the excavation task of the bucket. With the advent of hydraulic accessories such as crushers, grabs or augers, excavators are widely used in many applications other than excavation. Many excavators are equipped with quick couplings to simplify the installation of accessories, thereby increasing the utilization rate of the machine on site. Excavators are usually used with loaders and bulldozers. Most wheeled, compact and some medium (11 to 18 tons) excavators have backfill (or bulldozer) blades. It fixes a bulldozer-like horizontal blade to the chassis to level and push the removed material back into the hole.
Major excavator manufacturers in the world
oktobar
Bobcat Company
Bucyrus International
Caterpillar
Deere
Downers
Doosan Infracore (formerly Daewoo Heavy Industries)-Including the Solar brand
HEPCO
Hitachi Construction Machinery
three one
Hyundai Heavy Industry
JC Bamford (JCB)
Kato Plant-a subsidiary of IHICM Ltd.
LBX (chain belt) excavator
ThyssenKrupp
KOBELCO Construction Machinery Co., Ltd.-produces Kobelco worldwide
Kobelco-a subsidiary of Kobe Steel, which also produces Kobelco
Kubota
Liebherr
Liugong
Lonking
L&T-Komatsu's subsidiary, as L&T Komatsu's business in the Indian market
Mahindra
Marion Power Shovel Company-ceased operations in 1997
Mitsubishi Heavy Industries-The excavator market is fully owned by Caterpillar.
Samsung Group → This business was acquired by Volvo Construction Equipment
Sandvik Mining and Construction
three one
SDLG-Subsidiary of Volvo Construction Equipment Corporation
ST dynamics
Sumitomo
Shantui
Tata Hitachi Construction Machinery Company-Hitachi Construction Machinery Company for the Indian market
Terex Corporation
Uralva Gunzavod
Volvo Construction Equipment
Wacker Neuson
Xugong Group
XGMA
Yanmar
Yuchai
Zoomlion
