Intelligent bolt stretching device

Abstract

The utility model provides an intelligent bolt stretching device which comprises a stretching device cylinder body, a piston, a supporting frame and a displacement measuring device, high-pressure oil is injected into an oil cylinder and pushes the piston to move, meanwhile, the piston drags a bolt to apply load, and when the bolt is stretched, the bolt is stretched. And the displacement measuring device measures the displacement between the piston and the tensioner cylinder body in real time and feeds back the displacement to the control system, when the pre-tightening force reaches a preset value, the nut is locked, then the pressure of the oil cylinder is relieved, in the pressure relief process, the displacement measuring device continues to monitor the pressure-displacement relation of the return stroke of the oil cylinder, and the bolt fastening quality is evaluated based on the return result. The intelligent bolt stretching device solves the problems that a stretcher is controlled only by pressure, flange bolts can be fastened to a target value only through multi-round stretching and pre-tightening, and the uniformity is not ideal.

Description

Technical Field

[0001] This utility model relates to the field of bolt fastening technology, specifically to an intelligent bolt tensioning device. Background Technology

[0002] Bolt tightening is an indispensable process in all engineering projects. For industries and fields with high bolt tightening requirements, such as petrochemicals, construction, wind power, and nuclear power, the quality and control of bolt tightening are crucial guarantees for engineering installation and safe equipment operation. For these major projects, high-quality flange bolt tightening is the foundation for their safe operation.

[0003] Hydraulic tensioning relies on a hydraulic system to stretch bolts to a preset target force, followed by tightening the nut to maintain the bolt load. During tensioning, all bolts experience the same pressure, resulting in a uniform tensile load. However, after tightening the nut, uneven contact between the screw threads causes dispersion in the preload after the nut settles, requiring multiple rounds of tensioning to achieve the desired dispersion coefficient. Furthermore, existing tensioners only control hydraulic pressure and the bolt's tensile load, without simultaneously recording tensile displacement. When the preload approaches the yield load, some bolts may be overstretched or even break, seriously threatening equipment safety and limiting the maximum tensile load achievable with a tensioner. Utility Model Content

[0004] In view of the shortcomings of the existing technology, the purpose of this utility model is to provide an intelligent bolt tensioning device, which solves the problem that the tensioner relies solely on pressure control and requires multiple rounds of tensioning and pre-tightening to tighten the flange bolts to the target value and has poor uniformity.

[0005] To solve the above problems, the technical solution of this utility model is as follows:

[0006] An intelligent bolt tensioning device includes a tensioner cylinder, a piston, a support frame, and a displacement measuring device. High-pressure oil is injected into the cylinder to push the piston, which simultaneously pulls the bolt to apply load. During bolt tensioning, the displacement measuring device measures the displacement between the piston and the tensioner cylinder in real time and feeds it back to the control system. When the preload reaches a preset value, the nut is locked, and then the cylinder is depressurized. During the depressurization process, the displacement measuring device continues to monitor the pressure-displacement relationship of the cylinder's return stroke and evaluates the bolt tightening quality based on the return result.

[0007] Preferably, the displacement measuring device includes a flow sensor installed at the oil inlet of the hydraulic pump to record the flow-pressure curves during bolt loading and unloading. Combined with the cylinder size, it enables the evaluation of tensile and retraction displacements and the assessment of the fastening quality after the tensioned bolt is depressurized.

[0008] Preferably, the flow sensor is a flow meter.

[0009] Preferably, the displacement measuring device includes a displacement sensor installed at the support frame of the bolt tensioning device to measure the relative displacement between the support frame and the piston. The system synchronously records the tension displacement and system pressure to obtain the pressure-displacement relationship during the tightening and retraction processes, enabling the comparison of tension and retraction displacements and achieving intelligent evaluation of the tightening quality.

[0010] Preferably, the displacement sensor is a displacement gauge.

[0011] Compared with existing technologies, the intelligent bolt tensioning device provided by this utility model solves the problem that tensioners rely solely on pressure control, requiring multiple rounds of tensioning and pre-tightening to tighten flange bolts to the target value and exhibiting poor uniformity. Furthermore, based on the tension curve and load, it can control the bolts to be safely and reliably tightened to the yield and near-yield states, obtaining the maximum tightening force, improving the bolts' ability to resist external loads, and reducing the probability of thread loosening. Attached Figure Description

[0012] Other features, objects, and advantages of this invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0013] Figure 1 This is a cross-sectional schematic diagram of the intelligent bolt tensioning device of this utility model. Detailed Implementation

[0014] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the present invention in any way. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention.

[0015] Specifically, this utility model provides an intelligent bolt tensioning device, such as... Figure 1 As shown, the intelligent bolt tensioning device uses hydraulic tensioning to tighten bolts, and includes a tensioner cylinder 1, a piston 4, a support frame 2, and a displacement measuring device. During operation, high-pressure oil is injected into the cylinder and pushes the piston 4 to move, while the piston simultaneously drags the bolt to apply load. During bolt tensioning, the displacement measuring device measures the displacement between the piston 4 and the tensioner cylinder 1 in real time and feeds it back to the control system. After the preload reaches the preset value, the nut is locked, and then the cylinder is depressurized. During the depressurization process, the displacement measuring device continues to monitor the pressure-displacement relationship of the cylinder's return stroke and evaluates the bolt tightening quality based on the return result.

[0016] The key feature of this invention lies in its simple and convenient monitoring of the displacement-pressure relationship between the piston 4 and the tensioner cylinder 1 during bolt tightening. Based on a comparison of the loading and unloading processes, it intelligently assesses the actual preload of the bolt after tightening, thereby significantly improving the control accuracy of the actual bolt load after unloading and reducing the number of bolt tightening cycles. Furthermore, by combining the pressure-displacement relationship, it can monitor whether the bolt has entered the yielding stage during tightening, achieving tightening in the plastic zone or avoiding the risks posed by excessive plastic deformation to the bolt connection.

[0017] Regarding the measurement of piston displacement, the displacement measuring device of this utility model includes two methods. The first method: Since the bolt tensioning device is a one-way cylinder, a flow sensor is installed at the oil inlet position (low-pressure zone) of the hydraulic pump to record the flow-pressure curves during bolt loading and unloading. Combined with the cylinder dimensions, the tensioning and retraction displacements can be evaluated, and the tightening quality after the tensioned bolt is depressurized can be assessed. In this embodiment, the flow sensor is a flow meter. The second method: In Figure 1 A displacement sensor is installed at the support frame 2 of the bolt tensioning device shown to measure the relative displacement between the support frame 2 (stationary part) and the piston 4 (moving part). The system synchronously records the tension displacement and system pressure to obtain the pressure-displacement relationship during the tightening and retraction processes, realize the comparison of tension and retraction displacements, and achieve intelligent evaluation of tightening quality. In this embodiment, the displacement sensor is a displacement gauge.

[0018] In addition, to automate the bolt tensioning device, the system needs to add a human-machine interface screen for parameter input and result output, add a pressure sensor for automatic system pressure measurement, and add a data acquisition and calculation module for data acquisition, recording, and result evaluation. The system can also upload the fastening results to the server via Bluetooth and network.

[0019] The specific embodiments of this utility model have been described above. It should be understood that this utility model is not limited to the specific embodiments described above, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the substantive content of this utility model. Unless otherwise specified, the embodiments and features described in this application can be arbitrarily combined with each other.

Claims

1. An intelligent bolt tensioning device, characterized in that, The device includes a tensioner cylinder, a piston, a support frame, and a displacement measuring device. High-pressure oil is injected into the cylinder to push the piston to move. At the same time, the piston drags the bolt to apply load. When the bolt is stretched, the displacement measuring device measures the displacement between the piston and the tensioner cylinder in real time and feeds it back to the control system. When the preload reaches the preset value, the nut is locked. Then the cylinder is depressurized. During the depressurization process, the displacement measuring device continues to monitor the pressure-displacement relationship of the cylinder return stroke and evaluates the bolt tightening quality based on the return result.

2. The intelligent bolt tensioning device according to claim 1, characterized in that, The displacement measuring device includes a flow sensor installed at the oil inlet of the hydraulic pump. This flow sensor records the flow-pressure curves during the bolt loading and unloading process. Combined with the cylinder size, it enables the evaluation of tensile and retraction displacements and the assessment of the fastening quality after the tensioned bolt is depressurized.

3. The intelligent bolt tensioning device according to claim 2, characterized in that, The flow sensor is a flow meter.

4. The intelligent bolt tensioning device according to claim 1, characterized in that, The displacement measuring device includes a displacement sensor installed at the support frame of the bolt tensioning device. The sensor measures the relative displacement between the support frame and the piston. The system synchronously records the tension displacement and system pressure to obtain the pressure-displacement relationship during the tightening and retraction processes. This enables the comparison of tension and retraction displacements and achieves intelligent evaluation of the tightening quality.

5. The intelligent bolt tensioning device according to claim 4, characterized in that, The displacement sensor is a displacement meter.

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