Fastening bolt looseness detection device and detection method

Abstract

The invention belongs to the field of bolt structures, and particularly relates to a bolt detection device which comprises a bolt, a connecting piece, a bolt sleeve and a detection box, the bolt sleeve is rotatably arranged in the detection box, the bolt sleeve is provided with a bolt groove used for being arranged on the bolt in a sleeving mode, and the outer contour of the bolt sleeve is formed by splicing a semicircle and a semiellipse; the detection box is provided with a pair of detection assemblies, each detection assembly comprises a force sensor and an elastic rope, one end of each elastic rope is connected to the inner wall of the detection box, the other end of each elastic rope is connected with one force sensor, and when the bolt is fastened, the two elastic ropes are tangent to the two connecting points of the semicircle and the semiellipse of the outer wheel of the bolt sleeve respectively. According to the detection device provided by the invention, when the bolt is loosened, the bolt drives the bolt sleeve to rotate, the semicircular side elastic rope is always tangent, the semielliptical side elastic rope is jacked up to deform, the value of the force sensor of the deformed elastic rope changes, the deformation length of the elastic rope can be obtained according to the change value and the deformation curve, and the rotation angle of the bolt sleeve is calculated according to a geometric formula. Therefore, the looseness degree of the bolt is obtained.

Description

Technical Field

[0001] The invention relates to the field of bolt detection, and in particular to a device and method for detecting loosening of fastening bolts. Background Art

[0002] Bolt connection is the most commonly used connection method. It has been widely used in aerospace, mechanical engineering and civil engineering because of its high bearing capacity, high reliability and easy disassembly. my country's infrastructure has developed rapidly in recent years. Many large-scale engineering structures such as steel bridges and wind turbines use a large number of bolt structures. This type of large-scale engineering structure is complex. In terms of design and construction, most of them adopt the method of factory program processing components. After transportation, they are assembled and installed on site using bolted connections. Therefore, stable and reliable bolted connections are extremely important in the construction of this type of structure. In actual engineering applications, bolted connections are prone to loosening of bolted connections due to being in various high-intensity loads and extreme external environments for a long time. After loosening, the bolt preload drops rapidly, and the stability and reliability of the bolted connection structure are seriously affected, which poses a great safety hazard to industrial production, and is prone to structural damage, causing safety accidents, and even affecting the life safety of workers in serious cases. Therefore, bolt detection technology is of great significance.

[0003] The detection methods in the prior art include acoustic elastic effect detection, piezoelectric active sensor detection, strain resistor detection, etc. Among them, the acoustic elastic effect detection requires the emission of a longitudinal pulse wave to one end of the bolt and the reception of a reflected wave signal. The detection process is complicated and cannot be applied to large-scale detection. Piezoelectric active sensors and strain resistor detection add electronic components to receive electrical signals to obtain pressure changes and thus know the looseness of the bolt. The above methods require processing of the connector or the bolt itself to fix components such as wires and pressure sensors therein, and there are also certain application limitations. Summary of the invention

[0004] Therefore, the technical problem to be solved by the present invention is to provide a device for detecting loosening of fastening bolts to solve the problems existing in the prior art.

[0005] A device for detecting loosening of fastening bolts comprises a bolt, a connecting piece, a bolt sleeve and a detection box, wherein the bolt sleeve is rotatably arranged in the detection box, the bolt sleeve is provided with a bolt groove for being sleeved on the bolt, and the outer contour of the bolt sleeve is a combination of a semicircle and a semi-ellipse; the detection box is provided with a pair of detection components, each detection component comprises a force sensor and an elastic rope, one end of the two elastic ropes are connected to the inner wall of the detection box, and the other end is respectively connected to a force sensor, and when the bolt is tightened, the two elastic ropes are respectively tangent to the two connection points of the semicircle and the semi-ellipse of the outer wheel of the bolt sleeve.

[0006] Furthermore, a reset assembly is included for resetting the loosened bolts.

[0007] Furthermore, the reset assembly includes a handle connected to the bolt sleeve and an arc groove arranged on the detection box. The handle passes through the arc groove, and rotating the handle drives the bolt sleeve to rotate, thereby changing the tightness of the bolt.

[0008] Furthermore, a reference scale is provided on the edge of the arc-shaped groove, and when the handle is at the reference scale, it represents that the bolt is in a tightened state.

[0009] Furthermore, a processor is included for receiving force sensor data and calculating the degree of bolt loosening.

[0010] Furthermore, the detection box is fixed on the connecting piece.

[0011] The present invention also provides a detection method using the above-mentioned fastening bolt loosening detection device, comprising the following steps:

[0012] S1 sets the bolt head in the bolt sleeve according to the angle of the bolt when tightening, fixes the detection box on the connecting piece, and ensures that the two elastic ropes are tangent to the two connection points of the semicircle and semi-ellipse of the outer wheel width of the bolt sleeve respectively;

[0013] When the S2 bolt is loose, the values ​​of the two force sensors are obtained, and the deformation length of the elastic rope is obtained according to the deformation degree of the elastic rope and the elastic force change curve, and the rotation angle value of the bolt sleeve is calculated according to the deformation length;

[0014] S3 determines whether the bolt reaches a loosening threshold value based on the calculated rotation angle value, and issues a loosening warning if the threshold value is reached.

[0015] The present invention provides a fastening bolt loosening detection device, which is implemented by arranging a bolt head sleeve in a bolt sleeve, and rotatably arranging the bolt sleeve in a detection box, and by arranging the outer contour of the bolt sleeve into a splicing of a semicircle and a semi-ellipse, and arranging two elastic ropes tangent to the splicing point in the detection box. When the bolt is loose, the bolt drives the bolt sleeve to rotate, the elastic ropes on the semicircle side are always tangent, and the elastic ropes on the semi-ellipse side are lifted up and deformed, and the value of the force sensor of the deformed elastic rope changes. The deformation length of the elastic rope can be obtained according to the change value and the deformation curve, and the rotation angle of the bolt sleeve can be calculated according to a geometric formula, thereby obtaining the looseness degree of the bolt.

[0016] The fastening bolt loosening detection device provided by the present invention does not require processing of bolts or connectors, and bolt sleeves of corresponding shapes can be selected according to practical scenarios of the bolts. It has a wide range of application scenarios and is easy to use. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a structural diagram of the present invention;

[0018] Figure 2 This is a schematic diagram of the use state of the present invention;

[0019] Figure 3 This is a schematic diagram of the bolt loosening angle calculation method; DETAILED DESCRIPTION

[0020] Embodiment 1:

[0021] like Figure 1-2 The present invention as shown provides a fastening bolt loosening detection device, including a bolt, a connecting piece, a bolt sleeve 2 and a detection box 3, wherein the bolt sleeve 2 is rotatably arranged in the detection box 3, the bolt sleeve 2 is provided with a bolt groove for being sleeved on the bolt, and the outer contour of the bolt sleeve 2 is the splicing of a semicircle and a semi-ellipse; the detection box 3 is provided with a pair of detection components 4, each detection component 4 includes a force sensor 41 and an elastic rope 42, one end of the two elastic ropes 42 are connected to the inner wall of the detection box 3, and the other end is respectively connected to a force sensor 41, and when the bolt is tightened, the two elastic ropes are respectively tangent to the two connection points of the outer semicircle and the semi-ellipse of the bolt sleeve 2.

[0022] When the bolt is loose, it is necessary to tighten the bolt. The present invention provides a reset structure for resetting the bolt without disassembling the device, wherein the reset structure is a reset component arranged in the detection box 3, including a handle connected to the bolt sleeve 2 and an arc groove arranged on the detection box 3, an end of the handle is fixed to the outside of the bolt sleeve 2, and the other end extends through the arc groove, and the edge of the arc groove can refer to the scale line. When the bolt is tightened, the position of the handle is located at the reference scale line. When the bolt is loose, the handle is away from the scale line. The operator holds the handle and rotates the bolt sleeve to the scale line to reset the bolt.

[0023] Embodiment 2:

[0024] This embodiment provides a method for detecting loose bolts based on the device for detecting loose bolts in Embodiment 1. Figure 3 As shown, the short semi-axis of the bolt sleeve semi-ellipse is the same as the semi-circle radius. When the bolt is loosened and the bolt sleeve rotates, the elastic rope on the semi-circle side is always tangent to the bolt sleeve contour, and the other elastic rope is lifted up by the semi-ellipse and deformed. The initial length of the contact point between the force sensor and the elastic rope and the bolt sleeve is set to L, and the length between the contact point and the force sensor after deformation is L'. Figure 3 After the deformation, the vertical direction is S. The lateral displacement distance of the contact point here is very small and can be ignored. Then we have , set the rotation angle to θ, then Figure 3 The following relationship exists , where R0 is the length of the major semi-axis of the semi-ellipse, R is the distance from the center point of the bolt sleeve to the connection point, and R=S+r, where r is the length of the minor semi-axis of the semi-ellipse. From the above, the value of the rotation angle θ can be obtained. The elastic rope deformation degree and the force sensor value in this embodiment are known in advance by measuring and drawing curves in advance.

[0025] It is easy for those skilled in the art to understand that, under the premise of no conflict, the above-mentioned advantageous methods can be freely combined and superimposed.

[0026] The above embodiments are intended to illustrate the present invention, not to limit the present invention. Any solution that is a simple transformation of the present invention belongs to the protection scope of the present invention.

Claims

1. A fastening bolt loosening detection device, comprising a bolt, a connecting piece, a bolt sleeve (2) and a detection box (3), wherein the bolt sleeve (2) is rotatably arranged in the detection box (3), characterized in that: The bolt sleeve (2) is provided with a bolt groove for being sleeved on the bolt, and the outer contour of the bolt sleeve (2) is a combination of a semicircle and a semi-ellipse; the detection box (3) is provided with a pair of detection components (4), each detection component (4) comprises a force sensor (41) and an elastic rope (42), one end of the two elastic ropes (42) are connected to the inner wall of the detection box (3), and the other end is respectively connected to a force sensor (41), and when the bolt is tightened, the two elastic ropes are respectively tangent to the two connection points of the semicircle and the semi-ellipse of the outer wheel of the bolt sleeve (2).

2. A fastening bolt loosening detection device according to claim 1, characterized in that: Also included is a reset assembly for resetting the loosened bolts.

3. A fastening bolt loosening detection device according to claim 2, characterized in that: The reset assembly comprises a handle connected to the bolt sleeve (2) and an arc groove arranged on the detection box (3); the handle passes through the arc groove, and rotating the handle drives the bolt sleeve (2) to rotate, thereby changing the tightness of the bolt.

4. A fastening bolt loosening detection device according to claim 3, characterized in that: A reference scale is provided on the edge of the arc-shaped groove, and when the handle is at the reference scale, it represents that the bolt is in a tightened state.

5. The device for detecting loosening of fastening bolts according to claim 1, characterized in that: The device also includes a processor for receiving data from the force sensor (41) and calculating the degree of bolt loosening.

6. A fastening bolt loosening detection device according to claim 1, characterized in that: The detection box (3) is fixed on the connecting piece.

7. A detection method using the fastening bolt loosening detection device according to any one of claims 1 to 6, characterized in that: The steps include: S1 sets the bolt head in the bolt sleeve (2) according to the angle of the bolt when it is tightened, fixes the detection box on the connecting piece, and ensures that the two elastic ropes are tangent to the two connection points of the semicircle and the semi-ellipse of the outer wheel of the bolt sleeve (2) respectively; When the S2 bolt is loose, the values ​​of the two force sensors are obtained, and the deformation length of the elastic rope is obtained according to the deformation degree of the elastic rope and the elastic force change curve, and the rotation angle value of the bolt sleeve is calculated according to the deformation length; S3 determines whether the bolt reaches a loosening threshold value based on the calculated rotation angle value, and issues a loosening warning if the threshold value is reached.

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