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The working principle of non-rotating steel wire ropes
2025-07-08
I. Core Design: Multi-layer reverse twisting structure
Non-rotating steel wire ropes typically adopt a double-lay (multi-strand) symmetrical structure, consisting of an inner rope core and an outer multi-strand steel wire. The key lies in the fact that the lay directions of the inner and outer layers are opposite. Inner rope core: It is made by twisting several strands of steel wire in a certain direction (such as right twist), forming a basic force-bearing unit. Outer steel wire strands: They are twisted around the inner rope core in the opposite direction to the inner layer (such as left twist), and the number of outer strands is symmetrical to the structure of the inner layer (such as 6 strands in the inner layer and 6 strands in the outer layer). Ii. Mechanical Principles of Torque Cancellation When a steel wire rope is under tension, each strand of wire will have a "straightening tendency" due to the twisting Angle, which in turn generates a rotational torque on the entire rope (similar to the rotational force when a tightly wound spring is released). The torque is balanced by the non-rotating steel wire rope in the following way:The torque direction of a single strand: The twist direction determines the rotation direction of a single strand when subjected to force (a right-twisted strand tends to rotate to the right when under tension, while a left-twisted strand rotates to the left). Overall balance: The number of strands in the inner and outer layers is equal, the twist directions are opposite, and the cross-sectional areas and lengths of the strands are matched, so that the total torque generated by the inner layer is equal in magnitude and opposite in direction to the total torque of the outer layer. Eventually, the total torque approaches zero, achieving a "non-rotation" effect. Iii. Additional Design: Enhance stability Rope core support: The inner layer usually adopts fiber core or steel core, which not only enhances the overall strength but also fixes the position of the outer strands, avoiding torque imbalance caused by misalignment between strands when subjected to force.Precision twisting parameters: By controlling the lay length (the axial distance of each steel wire rotating one full circle) and lay Angle (the Angle between the steel wire and the rope axis) of the inner and outer layers, the accuracy of torque cancellation is ensured. For instance, the twist of the outer layer might be slightly greater than that of the inner layer to accommodate the slight deformation under force and maintain torque balance. |
