CN115383454A - Stud bolt screwing device and control method - Google Patents

Abstract

The invention relates to the technical field of high-precision industrial automatic assembly, in particular to a stud bolt screwing device and a control method, and the stud bolt screwing device comprises a screwing driving device, a height measuring device and a screwing controller, wherein the height measuring device is arranged on the screwing driving device and is used for detecting a displacement compression numerical value which is used for calculating the exposure height H of a stud bolt; the tightening controller comprises a tightening control module and a PLC control module, the tightening control module is electrically connected to the tightening driving device and is used for acquiring the current tightening torque T and the threshold angle A of the tightening driving device, the PLC control module is electrically connected to the height measuring device and is used for acquiring the displacement compression amount value and calculating the current exposure height H. The invention can improve the assembly precision and reduce the repair risk, thereby greatly improving the assembly efficiency and quality.

Description

Stud bolt screwing device and control method

Technical Field

The invention relates to the technical field of high-precision industrial automatic assembly, in particular to a double-end stud screwing device and a control method.

Background

With the continuous development of high-precision manufacturing industry, the connection mode is continuously updated in the mechanical assembly process. Among them, the stud bolt is widely used, and particularly, it is used in some workpiece connection places where the material of the body is not allowed to be tightened repeatedly. For example, in the industries and fields of aerospace, automobiles and the like, the stud bolt screwing is used as a common fastener technology, and the correct, standard and effective installation of the stud bolt is very important for ensuring that a joint surface meets the pre-tightening force required by the process, and plays a very important role in ensuring the performance and the structural safety of a host machine. Even if a fastener with excellent performance is used, if the fastener is not installed properly or tightened improperly, for example: torque out-of-tolerance, false torque, exposed height out-of-tolerance and the like can also cause screwing failure and system paralysis, and even threaten equipment and personal safety.

At present, when the stud is used for connection, one end of the stud needs to be screwed into a screw hole of a connected main body on one side, like the situation that one stud is arranged on the main body, a connected auxiliary body on the other side is generally provided with a through hole, the length of the stud in the main body extending out after penetrating through the connected auxiliary body is called the exposure height, and the main body and the auxiliary body can be tightly attached by using a nut screwing mode after the exposure height is adjusted.

In order to ensure the reliability of connection, the tightening torque and the height of the bolt exposed out of the surface of the workpiece are controlled during tightening. The conventional method at present adopts full manual operation, and to ensure the precision of the tightening torque and the exposure height, a worker only can tighten and detect the tightening torque and then repeatedly repeat the actions, so that the efficiency is very low; in addition, the threaded hole in the main body and the stud are in interference fit, and the torque is large when the stud is screwed down, so that manual operation is laborious, and the labor intensity is high. Meanwhile, the control precision requirement of the exposure height is strict, the error is generally required to be not more than +/-0.2 mm, and the phenomenon that the screwing is too deep due to poor control often occurs after the screwing is finished. But the assembly process requires: if the tightening is excessive, the direct loosening and re-tightening are not allowed, the stud bolt must be re-selected for secondary tightening, so that the assembly difficulty is very high, meanwhile, manual assembly is very dependent on the proficiency and elaborateness of an operator, and although the large amount of re-work tightening still occurs, the production efficiency is seriously limited.

Disclosure of Invention

In view of the defects of the prior art, the invention provides a stud bolt screwing device and a control method, wherein hardware such as a height measuring device and a screwing controller is arranged, the screwing torque, the threshold angle and the stud bolt screwing length are sampled circularly simultaneously in the process of screwing the stud bolt at a high speed, and the stud bolt screwing length is controlled according to the data collected in real time and the process setting, so that the purposes of improving the assembly precision and reducing the repair risk are achieved, and the assembly efficiency and the assembly quality are greatly improved.

In order to achieve the above object, the present invention provides a stud bolt tightening device, including a tightening driving device, a height measuring device and a tightening controller, wherein the tightening driving device includes a housing, a driving device fixed to the housing, a mandrel movably connected to the housing, and a tightening sleeve connected to the mandrel, the driving device is drivingly connected to the mandrel to rotate the mandrel relative to the housing; the height measuring device is arranged on the screwing driving device and used for detecting a displacement compression quantity value which is used for calculating the exposure height H of the stud; the tightening controller comprises a tightening control module and a PLC control module, the tightening control module is electrically connected to the tightening driving device and is used for acquiring the current tightening torque T and the threshold angle A of the tightening driving device, the PLC control module is electrically connected to the height measuring device and is used for acquiring the displacement compression quantity value and calculating the current exposure height H; the tightening controller is used for controlling the tightening speed and the stop of the tightening driving device according to the current tightening torque T, the threshold angle A and the current exposure height H, and judging whether the tightening is qualified or not.

Furthermore, the output end of the driving device is connected with a driving gear, and the driving gear is meshed with a driven gear sleeved outside the mandrel.

Further, the height measuring device comprises a first displacement sensor and a second displacement sensor, wherein the first displacement sensor is used for measuring the displacement compression amount value h1 of the housing reference point of the screwing driving device; and the second displacement sensor is used for measuring the displacement compression amount value h2 of the mandrel datum point of the screwing driving device.

Preferably, the housing includes a fixed portion rotatably connected to the mandrel, a floating portion displaceable in an axial direction of the mandrel relative to the fixed portion, and a first elastic element disposed between the fixed portion and the floating portion; the first displacement sensor is used for measuring the displacement compression amount value h1 of the first elastic element.

Further, a first limiting plate is sleeved and fixed on the outer side of the mandrel, a second limiting plate is mounted on the fixing part, and a second elastic element is arranged between the first limiting plate and the second limiting plate; the second displacement sensor is used for measuring the displacement compression amount value h1 of the second elastic element.

Preferably, the first displacement sensor and the second displacement sensor are both contact displacement sensors having a full scale of 100mm, with an accuracy of 0.05% fs.

On the other hand, the technical scheme provided by the invention is a stud bolt screwing control method, which comprises a screwing stage control method, wherein the screwing stage control method comprises the following steps

Acquiring the current tightening torque T in real time;

acquiring a displacement compression value H1 of a shell datum point of the screwing driving device and a displacement compression value H2 of a mandrel datum point of the screwing driving device in real time, and calculating the current exposure height H;

acquiring tightening torque process set parameters, and comparing the tightening torque process set parameters with the current tightening torque T;

acquiring an exposure height process setting parameter, and comparing the exposure height process setting parameter with the current exposure height H;

judging whether the tightening speed is adjusted or not according to the comparison result, and controlling the tightening driving device to switch the tightening speed if the tightening speed needs to be adjusted;

and controlling the tightening driving device to stop tightening until the current tightening torque T is equal to the tightening torque process set parameter or the current exposure height H is equal to the exposure height process set parameter.

Further, the stud bolt tightening control method further includes a torque and angle method determination method including

Setting a threshold torque;

collecting the current tightening torque T and comparing the current tightening torque T with the threshold torque;

when the current tightening torque T exceeds the threshold torque, an angle encoder is cleared to zero and begins to record a tightening angle value;

stopping recording the angle after the screwing is finished to obtain a final screwing corner;

and determining the final screwing corner as a threshold angle A, if the threshold angle A exceeds the angle process range, the screwing is unqualified, and if the threshold angle A is within the angle process range, the screwing is qualified.

The invention has the beneficial effects that: hardware such as a height measuring device and a screwing controller is arranged, the screwing torque, the threshold angle and the screwing length of the stud are sampled circularly at the same time in the process of screwing the stud at a high speed, and the stud is controlled according to the data collected in real time and the process setting, so that the purposes of improving the assembly precision and reducing the repair risk are achieved, and the assembly efficiency and the quality are greatly improved.

Drawings

FIG. 1 is a schematic structural view of a stud tightening device according to an embodiment of the present invention;

fig. 2 is a schematic structural view of a tightening driving device according to an embodiment of the present invention;

FIG. 3 is a flow chart illustrating a method for controlling a tightening phase according to an embodiment of the present invention;

FIG. 4 is a flow chart illustrating a torque and angle method of determining according to an embodiment of the present invention.

In the figure: 100. a screwing driving device 110, a shell 111, a fixed part 112, a floating part 113, a first elastic element 114, a limit column 120, a driving device 121, a driving gear 122, a driven gear 130, a mandrel 131, a first limit plate 132, a second limit plate 133, a second elastic element 140, a screwing sleeve,

200. a height measuring device, 210, a first displacement sensor, 220, a second displacement sensor, 230, a sensor holder,

300. a tightening controller 310, a tightening control module 320, a PLC control module,

1. a stud.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

In the technical field of aerospace and aeroengine assembly, a casing stud is often adopted as a fastener for fastening. The embodiment provides a stud bolt screwing device and a control method, and is applied to the screwing of a casing stud bolt. It should be noted that there are generally two broad categories of studs: the stud of the first type is provided with threads on the whole body, and the stud of the second type is provided with threads only at two ends (the specifications of the threads at the two ends are different).

Referring to fig. 1 and 2, the stud bolt tightening apparatus according to the present embodiment includes a tightening driving device 100, a height measuring device 200, and a tightening controller 300; wherein the tightening driving device 100 is used for executing the tightening action of the stud bolt, the height measuring device 200 is used for collecting height related data, and the tightening controller 300 is used for data processing and controlling the tightening according to real-time data.

Specifically, referring to fig. 2, the tightening driving device 100 includes a housing 110, a driving device 120 fixed to the housing 110, a mandrel 130 movably connected to the housing 110, and a tightening sleeve 140 connected to one end of the mandrel 130, wherein the driving device 120 is connected to the mandrel 130 to rotate the mandrel 130 relative to the housing 110, and the rotation of the mandrel 130 simultaneously rotates and displaces the tightening sleeve 140. Specifically provided, in one embodiment, a driving device is drivingly connected to the spindle 130 so that the spindle 130 can rotate and axially displace with respect to the housing 110, and a tightening sleeve 140 connected to one end of the spindle 130 is synchronously rotated and axially displaced to install the stud 1 in the tightening sleeve 140, or to screw the stud 1 already installed in the tightening sleeve 140 into a threaded hole of a connected body. The driving device 120 may be a driving motor or other driving device, the driving connection manner is not limited to the gear transmission manner in fig. 2, and the driving device may be powered to the spindle 130. In a specific arrangement, as an example, the output end of the driving device 120 is connected with a driving gear 121, and the driving gear 121 is engaged with a driven gear 122 sleeved outside the mandrel 130.

Referring to fig. 1 and 2, a height measuring device 200 is installed on the tightening driving device 100, and the height measuring device 200 is used for detecting a displacement compression value, which is used for calculating the exposure height H of the stud; the tightening controller 300 includes a tightening control module 310 and a PLC control module 320, the tightening control module 310 is electrically connected to the tightening driving device 100, the tightening control module 310 is used for acquiring a current tightening torque T and a threshold angle a of the tightening driving device 100, the PLC control module 320 is electrically connected to the height measuring device 200, the PLC control module 320 is used for acquiring a displacement compression amount value and calculating a current exposure height H; the tightening controller 300 is configured to control the tightening speed and stop of the tightening drive device according to the current tightening torque T, the threshold angle a, and the current exposure height H, and determine whether the tightening is acceptable.

According to the stud bolt tightening device, the height measuring device 200 is mounted on the tightening driving device 100, the height measuring device 200 is used for detecting the displacement compression quantity value, the exposure height H of the stud bolt is further obtained, the PLC control module 320 and the tightening controller 300 are arranged, the tightening speed and the tightening stop of the tightening driving device are controlled according to the current tightening torque T, the threshold angle A and the current exposure height H, and whether the tightening is qualified or not is judged, so that the assembling precision can be improved, the repair risk is reduced, and the assembling efficiency and the assembling quality are further greatly improved.

Referring to fig. 2, in an embodiment, the height measuring device 200 includes a first displacement sensor 210 and a second displacement sensor 220, the first displacement sensor 210 is used for measuring a displacement compression amount value h1 of a housing reference point of the tightening driving device; the second displacement sensor 220 is used for measuring the displacement compression amount value h2 of the mandrel reference point of the tightening driving device.

It should be noted that the specific number of the height measuring devices 200 and the specific installation positions can be set as required, and only the screw-in length of the screw column needs to be circularly sampled through data acquisition, so as to calculate the current exposure height H. As an example, referring to fig. 2, the housing 110 includes a fixed portion 111 rotatably coupled to the stem 130, a floating portion 112 displaceable relative to the fixed portion in an axial direction of the stem 130, and a first elastic member 113 disposed between the fixed portion 111 and the floating portion 112. In the embodiment, the floating portion 112 is a plate-shaped structure and is connected to the position-limiting pillar 114, the position-limiting pillar 114 moves synchronously with the floating portion 112 and penetrates through the fixing portion 111, and the measuring end of the first displacement sensor 210 abuts against one end of the position-limiting pillar 114 away from the floating portion 112. The first displacement sensor 210 is used to measure the displacement compression value h1 of the first elastic element. On the basis of this embodiment, the first limiting plate 131 is sleeved and fixed outside the mandrel 130, the second limiting plate 132 is installed on the fixing portion 111, and the second elastic element 133 is disposed between the first limiting plate 131 and the second limiting plate 132. Specifically, when the positioning device is installed, a limiting sleeve is installed on the fixing portion 111 of the housing 110, the mandrel 130 is arranged in the limiting sleeve in a penetrating manner, the measuring end of the second displacement sensor 220 is fixed at one end of the mandrel 130 far away from the tightening sleeve 140, and the second elastic element 133 is sleeved outside the mandrel 130 in the limiting sleeve. The second displacement sensor 220 is used for measuring the displacement compression amount value h1 of the second elastic element 133. It should be noted that, in the present embodiment, the first elastic element 113 and the second elastic element 133 both include springs, and the specifications of the springs can be selected according to specific needs.

Preferably, in one embodiment, the first displacement sensor 210 and the second displacement sensor 220 are both contact displacement sensors that are 100mm full scale, 0.05% accurate FS. Specifically, the sensor holder 230 is mounted at a suitable position on the housing 110, and the fixed ends of the first displacement sensor 210 and the second displacement sensor 220 are mounted on the sensor holder 230. In one embodiment, the driving device 120 adopts a servo motor with 750w power, the maximum rotating speed of an output head is 160rpm, the precision of dynamic torque of a tightening shaft is less than or equal to +/-2%, the precision of an angle of the tightening shaft is less than or equal to +/-1 ℃, and a DEN-MACU1101 special controller is adopted by a tightening control system.

In the technical field of stud bolt tightening control, in the related art, a tightening process can only directly control tightening torque, and pretightening force and exposure height of a connected part are controlled by detecting a real-time torque value of a stud bolt. The tightening torque T is in direct proportion to the pretightening force F, but is in inverse proportion to the exposure height H, so that the pretightening force F and the exposure height H can be reflected simply through the tightening torque T, but the tightening torque coefficient K of the stud can be changed along with the difference of the smoothness, the lubrication condition, the tightening speed and the used tightening tool of the thread surface and the seat surface, and meanwhile, the K value is also in relation with the temperature, and experiments prove that the torque coefficient K is reduced by 0.31 percent when the environmental temperature is increased by 1 percent. Although the torque method is simple in control strategy and few in set parameters, the torque method cannot be distinguished if false torque (loose connection) occurs. The height can only be detected after being screwed down, if the height is found to be improper, the height is adjusted, so that time and labor are wasted, and the control precision of the exposed height of the screw column is difficult to improve.

In view of the above drawbacks, referring to fig. 3, the technical solution provided by the present invention is a stud bolt tightening control method, including a tightening stage control method, which includes the specific steps of:

s1, collecting the current tightening torque T in real time; acquiring a displacement compression value H1 of a shell datum point of the screwing driving device and a displacement compression value H2 of a mandrel datum point of the screwing driving device in real time, and calculating the current exposure height H;

s2, acquiring a tightening torque process setting parameter, and comparing the tightening torque process setting parameter with the current tightening torque T; synchronously acquiring process setting parameters of the exposure height, and comparing the process setting parameters with the current exposure height H;

s3, judging whether the tightening speed is adjusted or not according to the comparison result, and controlling the tightening driving device to switch the tightening speed if the tightening speed needs to be adjusted; and controlling the tightening driving device to stop tightening until the current tightening torque T is equal to the tightening torque process set parameter or the current exposure height H is equal to the exposure height process set parameter.

Further, referring to fig. 4, in an embodiment, the stud tightening control method further includes a torque and angle method determination method, and the torque and angle method determination method includes the specific steps of:

step H1, setting a threshold torque;

h2, collecting the current tightening torque T, and comparing the current tightening torque T with a threshold torque;

h3, when the current tightening torque T exceeds a threshold torque, resetting the angle encoder to record a tightening angle value; stopping recording the angle after the screwing is finished to obtain a final screwing corner;

and H4, determining that the final screwing corner is a threshold angle A, if the threshold angle A exceeds the angle process range, the screwing is unqualified, and if the threshold angle A is in the angle process range, the screwing is qualified.

According to the stud bolt screwing control method, in the process of screwing the stud bolt at a high speed, sensor values of three channels, namely the current screwing torque T, the threshold angle A and the current exposure height H are detected at the same time, a system calculates according to the cycle sampling values to judge whether the screwing speed needs to be switched at present and finally stops, a PLC synthesizes various measurement values to give a judgment result after the final screwing is finished, and the positions of qualified/unqualified bolt points and screwing data are visually displayed on the HMI. And further greatly improves the screwing efficiency.

In the description of the present invention, it is to be understood that the terms "central," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," "circumferential," and the like are used in the orientations and positional relationships indicated in the drawings for convenience in describing the invention and to simplify the description, and are not intended to indicate or imply that the referenced device or element must have a particular orientation, be constructed and operated in a particular orientation, and are not to be considered limiting of the invention.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.

In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; they may be directly connected or indirectly connected through intervening media, or they may be connected internally or in any other suitable relationship, unless expressly stated otherwise. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

In the present invention, unless expressly stated or limited otherwise, the first feature "on" or "under" the second feature may be directly contacting the second feature or the first and second features may be indirectly contacting each other through intervening media. Also, a first feature "on," "over," and "above" a second feature may be directly or diagonally above the second feature, or may simply indicate that the first feature is at a higher level than the second feature. A first feature "under," "beneath," and "under" a second feature may be directly under or obliquely under the second feature, or may simply mean that the first feature is at a lesser elevation than the second feature. It will be understood that when an element is referred to as being "secured to" or "disposed on" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and the like as used herein are for illustrative purposes only and do not denote a unique embodiment.

Claims (8)

1. Stud bolt tightening device, its characterized in that: comprises that

The tightening driving device comprises a shell, a driving device fixed on the shell, a mandrel movably connected with the shell and a tightening sleeve connected with the mandrel, wherein the driving device is in transmission connection with the mandrel so as to enable the mandrel to rotate relative to the shell;

the height measuring device is arranged on the screwing driving device and used for detecting a displacement compression quantity value which is used for calculating the exposure height H of the stud; and

the tightening controller comprises a tightening control module and a PLC control module, the tightening control module is electrically connected to the tightening driving device and is used for acquiring the current tightening torque T and the threshold angle A of the tightening driving device, the PLC control module is electrically connected to the height measuring device and is used for acquiring the displacement compression quantity value and calculating the current exposure height H;

the tightening controller is used for controlling the tightening speed and the tightening stop of the tightening driving device according to the current tightening torque T, the threshold angle A and the current exposure height H, and judging whether the tightening is qualified or not.

2. The stud bolt tightening apparatus according to claim 1, wherein: the output end of the driving device is connected with a driving gear, and the driving gear is meshed with a driven gear sleeved on the outer side of the mandrel.

3. The stud bolt tightening apparatus according to claim 1, wherein: the height measuring device comprises

A first displacement sensor for measuring a displacement compression amount value h1 of a housing reference point of the tightening driving device; and

and the second displacement sensor is used for measuring the displacement compression amount value h2 of the mandrel datum point of the screwing driving device.

4. The stud bolt tightening apparatus according to claim 3, wherein: the shell comprises a fixed part which is rotationally connected with the mandrel, a floating part which can move along the axial direction of the mandrel relative to the fixed part, and a first elastic element which is arranged between the fixed part and the floating part; the first displacement sensor is used for measuring the displacement compression amount value h1 of the first elastic element.

5. The stud bolt tightening apparatus according to claim 4, wherein: a first limiting plate is sleeved and fixed on the outer side of the mandrel, a second limiting plate is mounted on the fixing part, and a second elastic element is arranged between the first limiting plate and the second limiting plate; the second displacement sensor is used for measuring the displacement compression amount value h1 of the second elastic element.

6. The stud bolt tightening apparatus according to any one of claims 3-5, wherein: the first and second displacement sensors are each a contact displacement sensor with a full scale of 100mm, with an accuracy of 0.05% FS.

7. The stud bolt screwing control method is characterized by comprising the following steps: comprises a control method of a tightening stage, which comprises

Acquiring the current tightening torque T in real time;

acquiring a displacement compression value H1 of a shell datum point of the screwing driving device and a displacement compression value H2 of a mandrel datum point of the screwing driving device in real time, and calculating the current exposure height H;

acquiring tightening torque process set parameters, and comparing the tightening torque process set parameters with the current tightening torque T;

acquiring an exposure height process setting parameter, and comparing the exposure height process setting parameter with the current exposure height H;

judging whether the tightening speed is adjusted or not according to the comparison result, and if the tightening speed needs to be adjusted, controlling the tightening driving device to switch the tightening speed;

and controlling the tightening driving device to stop tightening until the current tightening torque T is equal to the tightening torque process set parameter or the current exposure height H is equal to the exposure height process set parameter.

8. The stud bolt tightening control method according to claim 7, characterized in that: also included are methods for determining torque and angle, including

Setting a threshold torque;

collecting the current tightening torque T and comparing the current tightening torque T with the threshold torque;

when the current tightening torque T exceeds the threshold torque, an angle encoder is cleared to zero and begins to record a tightening angle value;

stopping recording the angle after the screwing is finished to obtain a final screwing corner;

and determining the final screwing corner as a threshold angle A, if the threshold angle A exceeds the angle process range, the screwing is unqualified, and if the threshold angle A is within the angle process range, the screwing is qualified.

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