Large industrial fans have longer blade lengths and hea […]
Large industrial fans have longer blade lengths and heavier blades, so that the root connection of the blades bears a greater load. The size of the blade root structure is large, and the blade root is the weak link of the overall structure. There are many failure modes of the connection, and Strength prediction is difficult, so the root connection of the blade is crucial.China Industrial Exhaust Fans Suppliers
At present, there are three main connection methods for industrial fan blade roots on the market: T-bolt connection, embedded bolt connection, and implanted bolt connection.
T-bolt connection is to make a circle of bolt holes uniformly in the circumferential direction perpendicular to the root end surface, and in the corresponding direction of the bolt, make a round nut hole in the radial direction perpendicular to the bolt hole. One end of the double-ended screw is connected to the round nut, and the other end is connected to the bearing installed on the hub. The double-headed bolt and nut form a T-shaped structure, so this connection is called T-bolt connection or cross-bolt connection. This is a reference The connection method of large-scale power generation windmill design. Since the bolt holes and the round nut holes are made after the blades are formed, the accuracy of the punching is also guaranteed by the equipment. There is no need to consider the root connection during the manufacture of the fan blades, nor will it be due to curing shrinkage during the blade manufacturing process. And affect the accuracy of root connection, so the manufacture of blades is relatively simple, especially suitable for companies that produce industrial fan blades in assembly lines.
The embedded bolt connection is composed of embedded bolt sleeve and double-ended screw. The outer surface of the embedded bolt sleeve has wavy or tooth-shaped annular protrusions, and the surface is sandblasted to improve the cleanliness and roughness of the surface. Before use, the continuous glass fiber bundle is wound to fill the groove. Because the root of the blade is formed by bonding two semi-cylindrical molds, the accuracy of the mold clamping also directly affects the accuracy of the bolt connection. Generally, the end face of the blade root connected with embedded bolts is no longer trimmed. The flatness is guaranteed by the flatness of the end face of the mold after forming and clamping. Therefore, the manufacture of the embedded bolt connection puts forward higher requirements on the rigidity of the mold root, the manufacturing accuracy and structural rationality of the embedded bolt positioning tooling, and the mold clamping accuracy and manufacturing process of the blade mold, and also increases the quality problems of the blade. The probability.
The implantable bolt connection is to make axial connection bolt holes on the end surface of the blade root as required, and insert the steel connection bolt into the axial connection bolt hole, and bond with epoxy adhesive. However, this method makes it impossible to replace the steel connecting bolt. An improved method is to implant a connector similar to a pre-embedded bolt sleeve in the axial connecting bolt hole, and then use a double-ended screw to connect to the host.