CN210005147U

CN210005147U - Stress monitoring bolt

Info

Publication number: CN210005147U
Application number: CN201921110193.0U
Authority: CN
Inventors: 王永洁; 顾青丽; 李晨晖
Original assignee: SHANGHAI SHENGUANG HIGH STRENGTH BOLTS CO Ltd
Current assignee: SHANGHAI SHENGUANG HIGH STRENGTH BOLTS CO Ltd
Priority date: 2019-07-16
Filing date: 2019-07-16
Publication date: 2020-01-31
Anticipated expiration: 2029-07-16

Abstract

The utility model provides an stress monitoring bolt, it includes the screw rod, the cross-section of screw rod is just circular, body shaping is provided with the end respectively at screw rod both ends, the end periphery is provided with the screw thread and the cross-section is just circular, two the length inequality of end in the axial direction is longer be provided with interior hexagonal depressed part on the terminal surface of end, stress monitoring chip sets up in the bottom of depressed part, through set up at screw rod both ends that axial direction length is unequal end makes the deformation that stress produced concentrate more in longer end side for the measurement accuracy of stress is higher, and the measuring result is also more stable.

Description

Stress monitoring bolt

Technical Field

The utility model relates to an kinds of stress monitoring bolt.

Background

At present, with the large-scale development of the wind power industry, for high-strength fasteners, a host factory pays more and more attention to exact real-time fastening axial force during bolt installation, and the intelligent high-strength bolts capable of monitoring the fastening axial force in real time have more urgent requirements.

The intelligent bolt can detect the current pretension value of bolted connection, can diagnose whether the connection structural member has faults of looseness, overload and the like, can early warn potential faults, and avoids major accidents.

According to the traditional intelligent bolt, the tension of the screw is directly detected in a mode that the strain gauge is arranged in the central hole in the bolt, the method is used for detecting the telescopic deformation of the screw by fixing the strain gauge in the hole in the bolt in a mode of bonding by using a bonding agent or filling and binding glue, and the strain of the screw cannot be directly transmitted to the strain gauge sensitive grid due to the use of the bonding agent, so that the problem of great time lag is caused. In addition, because the elastic modulus of the adhesive and the elastic modulus of the screw body are obviously different, the deformation relationship between the adhesive and the screw body has serious nonlinear relationship, the measurement range of the strain gauge is greatly limited, and the measurement precision is reduced. In addition, the strain gauge fixed by adopting the adhesive or the filling binding glue cannot be used in the occasions with higher temperature, so that the application range of the intelligent bolt is greatly limited.

In view of this, patent document 1(CN109632006A) discloses wireless intelligent bolts and an online monitoring system, which includes a bolt body, a force-measuring rod, a strain gauge, a temperature sensor, an integrated circuit board, a power supply device, a sealing cover, a local signal receiving and transmitting device and a terminal signal receiving and processing device, wherein a built-in hole with a fixed depth of is formed at the end of the non-threaded end of the bolt body, the bottom surface of the built-in hole is provided with the temperature sensor, the center of the bolt body is provided with a central hole with a fixed depth and diameter of , the bottom of the central hole is provided with a mounting thread, the end of the force-measuring rod is fixed at the bottom of the central hole of the bolt body through threaded connection, and the other end of the force-measuring rod is in close contact with the bottom surface of the built-in hole at the head of the.

However, in the field of wind power, blade bolts are used as important parts for connecting blades and hubs, bear large alternating load in the running process of a fan, and fatigue failure is more easily caused due to the fact that the blades are enlarged and lengthened, so that the quality requirement on products is higher. Because the blade bolt can bear larger alternating load in the operation process, the middle rod part can adopt a structure of a slender rod body to improve the fatigue resistance of the bolt in the common design.

In the case of a long and thin screw, the position of deformation of the screw due to stress is often not specified, or the degree of deformation is different at different screw positions, and therefore, if the technical solution of patent document 1 is adopted, the stress measurement result is difficult to maintain accurate and results.

SUMMERY OF THE UTILITY MODEL

The to-be-solved technical problem of the utility model is to provide stress measurement accuracy is higher, the more stable stress monitoring bolt of measuring result in order to overcome the defect that current stress monitoring bolt is difficult to keep precision and to send the nature when measuring the bolt of long and thin screw rod.

The utility model discloses an above-mentioned technical problem is solved through following technical scheme:

stress monitoring bolts are characterized by comprising a screw rod, wherein the cross section of the screw rod is in a regular circle shape, ends are respectively arranged at two ends of the screw rod in a body forming mode, threads are arranged on the periphery of each end, the cross sections of the ends are in the regular circle shape, the lengths of the two ends are not equal in the axial direction, an inner hexagonal concave part is arranged on the end face of the longer end, and a stress monitoring chip is arranged at the bottom of the concave part.

Preferably, the radius of the cross section of the end head is smaller than that of the cross section of the screw rod.

Preferably, the radius of the cross section of the end head is larger than that of the screw.

Preferably, the joint of the end head and the screw rod is formed into a circular truncated cone shape.

Preferably, the bottom of the concave part is also formed with tapered empty grooves.

Preferably, the stress monitoring chip is provided with an ultrasonic monitoring sensor.

Preferably, the stress monitoring chip is connected to a thin film sensor, and at least parts of the thin film sensor are attached to the joints of the terminals and the screws.

The utility model has the positive improvement effect that the two ends of the screw rod are provided with the ends with different axial lengths, so that the deformation generated by the stress is more concentrated on the longer end side, the measurement precision of the stress is higher, and the measurement result is more stable.

Drawings

Fig. 1 is a schematic structural view of a stress monitoring bolt according to embodiment 1 of the present invention.

Fig. 2 is a schematic structural view of a stress monitoring bolt according to embodiment 2 of the present invention.

Detailed Description

The present invention will be more clearly and completely described below by way of examples and with reference to the accompanying drawings.

Example 1

Fig. 1 is a schematic structural view of a stress monitoring bolt according to embodiment 1, and as shown in fig. 1, a stress monitoring bolt 100 according to embodiment 1 includes a screw 10, wherein a cross section of the screw 10 is a perfect circle,

ends

11 and 12 are respectively formed by at two ends of the screw 10, the outer peripheries of the

ends

11 and 12 are respectively provided with a thread 112 and a thread 122, and the cross sections of the

ends

11 and 12 are perfect circles.

Wherein, the end 11 is provided with an inner hexagonal recess 13 on the outer end face, and the bottom of the recess 13 is attached with a stress monitoring chip 20. The length of the tip 11 in the axial direction is larger than that of the tip 12.

The end head 11 is provided with the recessed part 13 of the hexagon socket, so that the stress borne by the end head 11 is larger, and the length of the end head 11 in the axial direction is larger than that of the end head 12, so that most of the shearing force of the stress monitoring bolt 100 is concentrated on the end head 11 side, so that deformation mainly occurs on the end head 11 side, and the stress monitoring chip 20 is located in the recessed part 13 and is close to a deformation generation area, so that the monitoring precision and the stability of a monitoring result are improved.

Furthermore, the cross-sectional radius of the

end heads

11, 12 is larger than the cross-sectional radius of the screw 10. The joints of the

ends

11 and 12 and the screw 10 are respectively formed into circular

truncated cone shapes

111 and 121. The stress monitoring chip 20 has an ultrasonic monitoring sensor (not shown in the figure).

Here, the joints of the

ends

11 and 12 and the screw 10 are both formed into a circular truncated cone shape, so that the end 12 can also share part of shearing force , and the screw 10 and the end 11 are less prone to fracture, and in addition, the circular truncated cone shape can better feed back ultrasonic signals for a stress monitoring chip using an ultrasonic monitoring sensor, so that the monitoring precision is further improved .

The performance index of the stress monitoring bolt 100 of example 1 can reach the following standard through practical monitoring: the hardness is 32-39 HRC, the tensile strength is not less than 1040MPa, the yield strength is not less than 940MPa, the elongation is not less than 9%, and the reduction of area is not less than 48%. The flatness of the bottom of the inner hexagonal concave part 13 is less than or equal to 0.02mm, the roughness is less than or equal to Ra0.8, and the area is larger than the diameter of the strain gauge by 2-3 mm. The depth of the recessed part 13 of the inner hexagon is deepened by 3mm than normal, and the use of the inner hexagon wrench is not influenced after the stress monitoring chip is pasted.

Example 2

Fig. 2 is a schematic structural view of a stress monitoring bolt according to embodiment 2. Embodiment 2 differs from embodiment 1 in that the cross-sectional radius of the screw 10 is slightly larger than the cross-sectional radius of the

heads

11, 12. The outer circumference of the screw 10 is slightly flush with the

threads

112, 122.

In addition, tapered recesses 131 are formed in the bottom of the recess 13.

The tapered slot 131 can obtain better feedback ultrasonic signals, so that the monitoring precision is further improved .

In addition, in some other embodiments, the stress monitoring chip 20 can be connected to a film sensor, at least portion of the film sensor can be attached to the outer surface of the thread 112 as shown in fig. 2, covering the connection between the tip 11 and the screw 10. the film sensor can also be arranged to be attached to the outer periphery of the connection between the tip 11 and the screw 10 in a ring shape.

Although particular embodiments of the present invention have been described above, it will be appreciated by those skilled in the art that these are examples only and that the scope of the present invention is defined by the appended claims. Various changes and modifications to these embodiments may be made by those skilled in the art without departing from the spirit and the principles of the present invention, and these changes and modifications are all within the scope of the present invention.

Claims

1, kinds of stress monitoring bolt, its characterized in that, it includes:

the section of the screw rod is in a perfect circle shape;

ends are respectively arranged at the two ends of the screw rod in a -shaped manner;

the periphery of the end head is provided with threads, the cross section of the end head is in a perfect circle shape,

the lengths of the two ends in the axial direction are unequal,

the end face of the longer end head is provided with an inner hexagonal concave part;

and the stress monitoring chip is arranged at the bottom of the depressed part.

2. The stress-monitoring bolt of claim 1,

the radius of the cross section of the end head is smaller than that of the cross section of the screw.

3. The stress-monitoring bolt of claim 2,

the radius of the cross section of the end head is larger than that of the cross section of the screw.

4. A stress-monitoring bolt according to any of claims 2 to 3,

the joint of the end head and the screw rod is in a circular truncated cone shape.

5. A stress-monitoring bolt according to claim 4,

the bottom of the recess is also formed with tapered voids.

6. A stress-monitoring bolt according to claim 5,

the stress monitoring chip is provided with an ultrasonic monitoring sensor.

7. A stress-monitoring bolt according to claim 5,

the stress monitoring chip is connected to a film sensor, and at least parts of the film sensor are attached to the joints of the terminals and the screws.