Overview of the Development History of the Power System for Fully Automatic Pipe Bending Machines

A pipe bender is a machine with an extremely broad range of applications, from small components like those used in refrigerators to the bending of large‑diameter pipelines. As technological advances across various industries have progressed, new demands have emerged for higher precision and integrated multi‑process capabilities in pipe‑bending equipment. The operating principle of a pipe bender involves applying a bending moment through appropriately positioned fulcrums and load points, inducing plastic deformation in the steel pipe and thereby achieving cold bending. The lower die is mounted at the front of the machine and suspended from the frame via a hydraulic cylinder, allowing it to remain floating. A lifting device guides the steel pipe from the rear of the machine, passing through a clamping mechanism and the upper die before being fed into the lower die. An internal mandrel is then inserted into the pipe and positioned at the center of the upper die; its expansion blocks press against the inner wall of the pipe, preventing abnormal deformation during the bending process.

Throughout the evolution of pipe bending machines, their power sources have been continuously refined and upgraded. In the early days, when pipes were bent manually, the primary driving force was the physical labor of one or more operators, and the products typically consisted of small-diameter tubing. This method suffered from low productivity, insufficient precision, and limited versatility in shaping pipe profiles. With advances in modern technology and rising industrial standards, high‑performance pipe benders such as CNC‑controlled models and three‑dimensional hydraulic bending machines have been developed. These advanced machines generally employ one of three main drive systems: electric motor drive, hydraulic drive, or a hybrid electric–hydraulic configuration.

1. Motor drive

In today’s modern industrial landscape, most machinery and equipment rely on electric motors as their primary power source, driving the fundamental operations of the entire system. While the motor serves as the initial power input, a variety of transmission mechanisms can be employed—such as gears, racks, cams, and linkages—to drive these components. Based on specific application requirements, a pipe‑bending machine can be designed to meet the desired performance criteria.

2. Hydraulic Drive

With the continuous advancement of industrial technology, hydraulic transmission has become one of the fastest‑growing technologies in mechanical equipment, particularly entering a new stage of development in recent years. Thanks to its advantages—high power transmission, high control accuracy, rapid response, and ease of integrating motor–hydraulic system control—hydraulic transmission and control systems are widely employed across various industries. A hydraulically powered pipe bender is a novel pipe‑bending device that boasts a rational structure, convenient operation, safe use, quick loading and unloading, and versatile functionality.

3. Electro-hydraulic hybrid drive

Although hydraulic pipe bending offers advantages such as high power transmission, precise control, and rapid response, it also has certain drawbacks: excessive operator movements lead to low production efficiency; significant machine wear reduces service life; and the need for a larger workforce results in higher labor costs, thereby increasing overall product costs. Therefore, further research proposes adopting a hybrid electromechanical–hydraulic drive system, which leverages the respective strengths of electric and hydraulic actuation to achieve the most efficient drive configuration, thereby reducing production costs, enhancing productivity, and improving machining accuracy.