Flexible universal shaft

Abstract

The invention discloses a flexible universal shaft. The external structure of a universal joint of the universal shaft is a petal type connecting body replaced by an elastic sleeve which is woven by elastic steel wires or steel bars, and flexible soft links are replaced by rigid hard links. Torque moment of the universal shaft is mainly born by the external structure of the universal joint, thus the universal shaft rotates flexibly and conveniently, and has extremely high wearing resistance. In normal operation, the torque moment transmits mainly through the steel wires or the steel bars. When the torque moment bears a torque force or other forces, because of flexibility of the torque moment, the impact of forces is slowed down, and the torque moment is transformed to a pulling force, the universal shaft is not easy to crack, and has longer service life. Detachable joint components are installed in an inner cavity of the elastic sleeve. Gaps between detachable joints are utilized to form rotation planes with different angles, and the adjustment of the detachable joints can be finished according to practical requirements, so that the realization of application angles in the industrial and mining and requirements of customers can be met.

Description

technical field [0001] The invention relates to a universal joint shaft with free curvature, in particular to a universal joint shaft suitable for screw drilling tools with different curvature change requirements. Background technique [0002] Screw drilling tools are widely used in many fields, such as: geological exploration, drilling, workover, development of gas beds, crossing construction of various pipelines and drilling operations in national defense projects. In recent years, in the drilling of oil and gas fields, screw drilling tools have been used in special process wells, and at this time it is required that screw drilling tools must be adapted to the conversion of various angles. Such as drilling directional wells, highly deviated wells, horizontal wells, extended reach wells, multi-branch wells, cluster wells, etc. It can also be used to drill vertical wells. [0003] The screw drilling tool is composed of four parts: bypass valve assembly, motor assembly, card...

AI Technical Summary

Problems solved by technology

This is because the currently used connecting shaft is to cut the thick-walled tube radially into two petals that engage with each other without breaking. The closed cutting line forms a certain gap, and the size of the gap depends on the size of the curvature range. The inner cavities of the two petals bear the pressure through the ball seat and the ball or the flexure rod device. At the same time, the petal body bears the torque transmission of the drilling tool, and gradually wears out during use, so that the gap between the petal seams gradually increases, while the ball seat and the ball or the flexure rod The wear of the rod also becomes smaller or shorter gradually, so that the axial gap gradually increases, so the petal body bears a certain axial pressure during work, and its working gap gradually becomes smaller, making the two petal bodies less and less Flexible, and increase the transmission torque, and increase the cutting gap of the petal body

When the gap increases to a certain range, the two petals are easy to disengage under the torque and tension of the drilling tool, which will inevitably cause drilling accidents. Therefore, due to the improvement of drilling requirements (referring to special craft wells, Highly deviated wells, horizontal wells, extended-reach wells, multi-branch wells, cluster wells, vertical wells, logging) during the drilling process, if the angle of the cardan shaft is small, it cannot adapt to the drilling of large-camber drilling tools, and the universal shaft must be replaced. to the axis, and the excessive curvature makes the local gap of the petals smaller and bears excessive torque, which accelerates the wear rate and causes the drill tool to fail early

In particular, the petal-type cardan shaft transmits torque through surface-to-surface friction. It not only has a relatively short working life, but also consumes a lot of mechanical energy during work, which reduces the output torque of the drilling tool and reduces the efficiency of the motor.

Therefore, the current structure of the cardan shaft is no longer suitable for various drilling operations.

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