Screwing mechanism and coupling centering and screwing device

Abstract

The invention discloses a screwing mechanism which is used for centering and screwing a coupling pre-screwed on a steel pipe and comprises an annular rotating part driven by a driving device to rotate, and the inner wall of a shaft hole of the annular rotating part is provided with at least two outwards-sunken arc-shaped adjusting faces. Main clamp assemblies are installed in the shaft hole and are arranged in one-to-one correspondence with the arc-shaped adjusting faces, the near end of each main clamp assembly is in rolling connection with the arc-shaped adjusting faces, and the far end of each main clamp assembly is arranged in a sliding mode in the radial direction under the matching action of a limiting mechanism and the arc-shaped adjusting faces, so that the main clamp assemblies can have a coupling clamping state or a receding state. The mechanism at least has the following advantages that centering clamping and screwing of the coupling can be achieved, and meanwhile, the coupling can be prevented from being damaged due to too large screwing force in the mode.

Description

technical field [0001] The invention relates to the technical field of collar tightening, in particular to a screwing mechanism and a collar centering screwing device. Background technique [0002] The statements in this section only provide background information related to the present disclosure and may not constitute prior art. [0003] The coupling is a kind of oilfield drilling tool, which mainly provides connection for the oil casing and oil pipe used in the downhole through the threads at both ends of the coupling. Usually, the seamless steel pipe used in the oil field is screwed on one end of the steel pipe with a coupling before leaving the factory, and the other end is only provided with a protective sleeve for the thread. When drilling in the oil field, the thread at the end with the protective sleeve is screwed into the coupling of the previous steel pipe. Inside, they are connected in turn to form the well wall of the oil well. [0004] The existing coupling t...

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Problems solved by technology

[0004] The existing coupling tightening device, such as the application number: 201220562170.5, is named: a Chinese patent for a coupling tightening device. There are main tongs and back tongs, the main tongs are respectively connected with a control device and a motor, the back tongs are connected to each other with a pressure sensor and a torque meter, and the back tongs are connected to the cylinder, the torque It can be seen that in the prior art, when the main tong is clamping the coupling, it is easy to clamp more tightly on one side eccentrically, and there is a gap on the other side, and the clamping effect is poor. It is prone to warping and poor screwing accuracy, and what's more, the screw teeth are easy to be screwed, which affects the connection performance and sealing performance between the coupling and the casing.

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