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Analysis of Design and Manufacture Technology of Concrete Pump Car Chassis
Concrete pump truck chassis is primarily composed of a rotating base, outriggers, swing cylinders, and telescopic cylinders. As the core structural component of the concrete pump truck, the chassis is typically designed as a box-shaped structure, which integrates both an internal fuel tank and a water tank. The rationality of this design directly affects the reliability, stability, and overall weight of the pump truck. At the BAUMA CHINA 2004 International Exhibition, numerous well-known domestic and international companies showcased their latest products and high-quality solutions, highlighting the level of chassis design and manufacturing. With the rapid development of China’s construction machinery industry, the technological gap between domestic concrete pump chassis and advanced foreign counterparts has been gradually narrowing. Domestic manufacturers have also made significant progress in structural design and production technology, drawing from years of experience in pump part design and manufacturing, as well as extensive participation in large-scale exhibitions.
The structure of a concrete pump truck chassis mainly consists of a rotating base and outriggers. The rotating base serves as the main support, bearing the weight and vibrations of the boom, while the outriggers ensure the safety and stability of the vehicle during operation. Unlike cranes, concrete pump trucks do not have counterweights, so when the boom extends horizontally, a large overturning moment is generated. This is mainly balanced by the reaction force from the outriggers, which must have sufficient structural dimensions and support area. Both the rotating base and outriggers require adequate strength and fatigue resistance.
Chassis structures are generally categorized based on how the outriggers extend: swing-type front and rear outriggers, telescopic front and rear outriggers, and the former type with telescopic swing legs.
Swing-type front and rear outriggers operate by pivoting around a central axis, offering good stability and a simple structure. However, they require sufficient space on both sides of the vehicle, which may limit their use in confined areas. Due to these constraints, most domestic and international manufacturers have adopted this structure.
Telescopic front and rear outriggers, also known as XH legs, allow the legs to extend and retract horizontally within the box-shaped frame of the rotating base. These legs can cross in an X-shape or extend parallel. However, due to limitations in vehicle width and the need for high-precision manufacturing of the rotating base frame, the overall weight tends to be heavier. Additionally, integrating a fuel tank inside the chassis makes disassembly and maintenance difficult. As a result, only a few manufacturers produce models above 37 meters. This structure was more common in early pump truck designs due to its flexible working space, and some manufacturers still use it today, such as CIFA and MEBCO.
The front telescopic swing leg structure combines the advantages of the previous two designs, offering reduced weight and a narrower working footprint. More manufacturers are now adopting this design. In 2004, XCMG became the first Chinese company to launch the HB40 model using this structure. Foreign manufacturers like Germany's PM and South Korea's brands also widely use similar designs for models up to 42 meters.
Designing and manufacturing the concrete pump truck chassis presents several challenges. The rotating base, as the main connecting component, requires complex structural design to ensure dynamic strength and rigidity, along with welds that can withstand vibration. Accurately calculating stress distribution across the rotating base is a major design challenge. XCMG has conducted extensive research on finite element analysis, achieving successful calculations and valuable design experience. Additionally, the rotating base often contains fuel and water tanks, making it crucial to prevent delayed cracking in welded areas. Leak prevention at weld joints is another critical manufacturing task. Common detection methods include magnetic particle inspection combined with kerosene testing, as well as ultrasonic testing. Domestic manufacturers choose the most economical approach based on their equipment capabilities.
In the rotating area of the chassis, where the slewing ring and reducer are connected, ensuring proper meshing characteristics is essential. To achieve this, manufacturers typically increase the rigidity of the components. The most widely used solution involves reinforcing thin ring plates or using thick seat plate connections. All manufacturers have explored effective ways to address these challenges.