CN115816355A - Control method of threaded fastener tightening device - Google Patents
Control method of threaded fastener tightening device Download PDFInfo
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- CN115816355A CN115816355A CN202211491176.2A CN202211491176A CN115816355A CN 115816355 A CN115816355 A CN 115816355A CN 202211491176 A CN202211491176 A CN 202211491176A CN 115816355 A CN115816355 A CN 115816355A
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Abstract
The invention discloses a control method of a screwing device of a threaded fastener, wherein the screwing device comprises a screwing head, a motor, a torque sensor and a speed reducer, and the motor drives the screwing head to rotate to screw the threaded fastener; the method comprises the following steps: monitoring the rotation number of the tightening head after the tightening head starts to screw the threaded fastener into the fastened object, and screwing the threaded fastener into the fastened object by the tightening head at an initial speed at a constant speed; when the number of rotation turns of the tightening head reaches a preset number of turns, controlling the speed reducer to reduce the rotation speed of the tightening head to a first speed, and triggering a torque sensor to detect the output torque of the monitoring motor; when the output torque of the motor reaches a first torque, controlling a speed reducer to reduce the rotating speed of the tightening head from a first speed to a second speed; when the output torque of the motor reaches the second torque, the motor is controlled to stop; the second torque is greater than the first torque. The invention can improve the screwing efficiency on the basis of ensuring the accuracy of screwing.
Description
Technical Field
The invention relates to the technical field of tightening devices, in particular to a control method of a tightening device of a threaded fastener.
Background
Generally, the locking of bicycle axles is realized through screwing screws, the force of screwing the screws cannot be too large, the screws are easily unscrewed or broken during the riding and using of users, so that the safety problem occurs, the locking of the axles cannot be caused by undersize, and the quality and the safety problem of unstable driving and even wheel separation occur during the riding and using of the users. Therefore, the existing screws for twisting bicycle axles are all screwed according to the set force meeting the safety requirements, so that the quality and the use safety of products are ensured. Meanwhile, in the bicycle assembly line production, a bicycle axle locking assembly line is specially arranged, and the available time of each assembly line operator is 30-40s, so that the requirement on the efficiency of the torque wrench is high.
For this, three types of torque wrenches are available on the market. One is a single-gear torque wrench, which sets a torque meeting safety requirements in advance, and has a very fast rotation speed, and the final tightening torque often exceeds the set torque due to the time delay of wrench control and the high rotation speed. The second is a slow torque wrench, which reduces the rotation speed on the basis of the first torque wrench, so that the final tightening torque is closer to the set torque, but the speed is too slow, the efficiency is low, and the device is not suitable for an axle locking assembly line of a bicycle. The third is a double-gear torque wrench, which sets two torques meeting the safety requirement in advance, and the second torque is realized by reducing the rotation speed, the final tightening torque of the scheme is smaller than the set second torque, and the scheme is also called as a mode of 'initial tightening and final tightening' in the prior art, such as the mode adopted by patent CN 202763750U; however, in order to achieve the final torque close to the preset torque, the rotation speed corresponding to the second torque in the third torque wrench is often set to be much smaller than that corresponding to the first torque, so that the second solution still has the problem of low efficiency.
Therefore, how to improve the tightening efficiency on the basis of ensuring the tightening accuracy makes the torque wrench suitable for the assembly line of bicycle axle locking very important.
Disclosure of Invention
The invention aims to provide a control method of a screwing device of a threaded fastener, which can improve the screwing efficiency on the basis of ensuring the screwing accuracy.
In order to solve the above technical problems, a first aspect of the present invention discloses a control method for a tightening device of a threaded fastener, the tightening device including a tightening head, a motor, a torque sensor, and a speed reducer, the motor driving the tightening head to rotate to tighten the threaded fastener; the method comprises the following steps:
monitoring the number of rotations of the tightening head after the tightening head starts to screw the threaded fastener into the fastened object, and screwing the threaded fastener into the fastened object by the tightening head at a constant speed at an initial speed;
when the number of rotation turns of the tightening head reaches a preset number of turns, controlling the speed reducer to reduce the rotation speed of the tightening head to a first speed, and triggering the torque sensor to detect and monitor the output torque of the motor;
when the output torque of the motor reaches a first torque, controlling the speed reducer to reduce the rotation speed of the tightening head from the first speed to a second speed;
when the output torque of the motor reaches a second torque, controlling the motor to stop; the second torque is greater than the first torque.
As an optional embodiment, in the first aspect of the present invention, the first speed and/or the first torque are determined according to a threaded fastener tightening model corresponding to a preset delay period and a model parameter of the threaded fastener.
As still another alternative embodiment, in the first aspect of the present invention, the delay period is a period between a start when the number of rotations of the tightening head reaches a preset number of rotations and an end when the reduction gear starts to reduce the rotation speed of the tightening head to the first speed.
As yet another alternative, in the first aspect of the present invention, the first torque is 75% of the second torque.
As a further alternative embodiment, in the first aspect of the present invention, the first speed is 50% of the initial speed.
As a further alternative, in the first aspect of the present invention, the second speed is 10% of the initial speed.
As yet another alternative embodiment, in the first aspect of the present invention, the threaded fastener is a screw for fastening a bicycle axle.
In a second aspect of the invention, there is disclosed a tightening apparatus characterized by steps in a control method for performing the threaded fastener tightening apparatus.
A third aspect of the present invention discloses a computer storage medium characterized by storing computer instructions for executing steps in the control method of the threaded fastener tightening apparatus when the computer instructions are invoked.
Compared with the prior art, the embodiment of the invention has the following beneficial effects:
compared with the prior art, the embodiment of the invention has the advantages that most parts of the threaded fastener are screwed into the fastened object at the beginning through higher speed and lower torque, and when the preset depth is reached (through setting the preset number of turns), the mode is switched to the mode of increasing the torque of the tightening head through reducing the rotating speed, so that the threaded fastener is screwed into the fastened object at higher torque to meet the pretightening force requirement of the threaded fastener; particularly, in a mode of reducing the rotating speed and improving the torque of the tightening head, the rotating speed is reduced twice continuously, and compared with a mode of directly reducing the rotating speed to a low speed, the mode of reducing the rotating speed to a low speed can realize less tightening time and efficiency, and can also realize more stable torque improvement and accuracy and safety.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.
Fig. 1 is a schematic flow chart of a control method of a threaded fastener tightening apparatus according to an embodiment of the present invention;
fig. 2 is a schematic diagram of a relationship between a screwing-in turn number and a screwing head torque (N × m) based on a 10-tooth screw tightening device according to an embodiment of the present invention;
fig. 3 is a schematic diagram of torque (N × m) of a tightening head with time(s) when a threaded fastener is screwed into an object to be fastened at a constant rotational speed according to an embodiment of the present invention.
Detailed Description
In order to make the technical solutions of the present invention better understood, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Example one
Referring to fig. 1, fig. 1 is a schematic flow chart illustrating a control method of a threaded fastener tightening apparatus according to an embodiment of the present invention. The tightening device comprises a tightening head, a motor, a torque sensor and a speed reducer, wherein the motor drives the tightening head to rotate to tighten the threaded fastener; the control method comprises the following steps:
101. after the tightening head starts to screw the threaded fastener into the fastened object, the number of rotations of the tightening head is monitored, and the tightening head screws the threaded fastener into the fastened object at a constant speed at an initial speed.
102. When the number of turns of the tightening head reaches a preset number of turns, the speed reducer is controlled to reduce the rotating speed of the tightening head to a first speed, and the torque sensor is triggered to detect and monitor the output torque of the motor.
103. When the output torque of the motor reaches a first torque, the speed reducer is controlled to reduce the rotating speed of the tightening head from the first speed to a second speed.
104. When the output torque of the motor reaches a second torque, controlling the motor to stop; the second torque is greater than the first torque.
In an embodiment of the invention, the second torque is set to a torque that causes the threaded fastener to have a better pretension.
In the embodiment of the invention, after the tightening head starts to screw the threaded fastener into the fastened object, the number of the rotation turns of the tightening head corresponds to the depth of the threaded fastener in the fastened object, and the torque output by the motor is changed along with the increase of the depth.
For example, when the threaded fastener is a 10-thread screw, the predetermined number of turns is 9 turns, the first torque is 30n × m, and the second torque is 40n × m, the relationship between the number of turns of screwing and the torque (N × m) of the tightening head of a 10-thread screw tightening apparatus to which the control method according to the embodiment of the present invention is applied is shown in fig. 2. In 1 turn, along with the entering of the screw, the extrusion force of the screw head on the contact surface of the fastened object is larger and larger, so that the friction force borne by the screw head is larger and larger, at the moment, the screw head overcomes the friction force within unit time and applies more and more work, and under the condition of unchanged rotating speed, the torque of the screw head is continuously increased; after 1 turn, the extrusion force of the screw entering from the back to the contact surface of the fastened object is far less than that of the screw head, and the friction force is only related to the extrusion force and the friction coefficient, so the friction force applied to the screw before 9 turns after 1 turn is basically equal to the friction force at the tail of 1 turn, at the moment, the tightening head does not work against the friction force in unit time, namely, the power is unchanged, and under the condition of unchanged rotating speed, the torque of the tightening head is basically equal to and basically unchanged at the tail of 1 turn; when 9 turns are reached, the tightening head speed is reduced, for example to 50% of the initial speed, since the friction is only related to the pressing force and the friction coefficient, and the friction is still constant, so that the work done against the friction per unit time is constant, i.e. the power is constant, and the torque of the tightening head is increased when the speed is reduced (the speed is gradually reduced to 50% due to inertia); when the torque of the tightening head reaches 30Nxm, the rotating speed of the tightening head is reduced again, and similarly, the friction force and the power are unchanged, and under the condition that the rotating speed is reduced, the torque of the tightening head is increased again, but the increasing speed of the torque is reduced; when the screw is screwed in for 10 turns, the screw is completely inserted into the fastened object.
It can be seen that the embodiment of the present invention, by screwing most of the threaded fastener into the fastened object at a higher speed and a lower torque at the beginning, when reaching a preset depth (by setting a preset number of turns), switches to a mode of increasing the torque of the tightening head by reducing the rotation speed, so that the threaded fastener is screwed into the fastened object with a higher torque to satisfy the pretension requirement of the threaded fastener; particularly, in a mode of reducing the rotating speed and improving the torque of the tightening head, the rotating speed is reduced twice continuously, and compared with a mode of directly reducing the rotating speed to a low speed, the mode of reducing the rotating speed to a low speed can realize less tightening time and efficiency, and can also realize more stable torque improvement and accuracy and safety.
In an alternative embodiment, the first speed and/or the first torque are determined according to a preset delay period and a corresponding tightening model of the threaded fastener. The tightening model corresponding to the threaded fastener is a threaded fastener tightening model corresponding to the model parameter of the threaded fastener, and comprises a relation model of torque of the threaded fastener changing along with time at different speeds.
Optionally, the delay time length is a time length between a start time when the rotation number of turns of the tightening head reaches a preset number of turns and a tail time when the speed reducer starts to reduce the rotation speed of the tightening head to the first speed.
In yet another alternative embodiment, the second torque may be 40n × m, or may be other torque values, as long as sufficient pretension is provided for the threaded fastener.
In yet another alternative embodiment, the first torque may be 30n × m. According to the empirical summary of the actual work, fig. 3 is a schematic view showing the change of the torque (N × m) of the tightening head with time(s) when the screw fastener is screwed into the fastened object at a uniform rotation speed, wherein the torque change rate when the torque is larger than 30n × m is higher than when the torque is smaller than 30n × m, and since the time from transmitting information from the torque sensor to the deceleration of the speed reducer takes 20-30ms when the torque sensor detects that the torque reaches the first torque, an error between the torque at the time of actually starting the deceleration and the first torque is caused in the time of 20-30ms, specifically, in the time of 20-30ms, the torque error when the first torque is set to be larger than 30n × m is higher than the torque error when the first torque is set to be smaller than or equal to 30n × m; therefore, in order to ensure a good torque error, the first torque should be set to 30n × m or less. Meanwhile, since the first torque is decelerated and the torque increasing speed is decreased, the first torque is set to 30n × m in order to shorten the time for the torque to reach the second torque and to take the torque error into consideration.
In yet another alternative embodiment, the first torque may be 75% of the second torque. For example, when the second torque is set to 40n × m, the first torque may be 30n × m.
In yet another alternative embodiment, the initial speed may be 600-800r/min. Wherein, the rotating speed of the motor is 3000-4000r/min, the rotating speed of the motor is reduced to 600-800r/min by the reduction gearbox according to the proportion of 1.
In yet another alternative embodiment, the first speed may be 50% of the initial speed. As can be seen from fig. 2, when the rotation speed decreases, the torque change rate at the relatively high rotation speed is greater than the torque change rate at the lower rotation speed. However, if the rotating speed is too high, a higher torque error is easily caused; if the rotating speed is too low, the use efficiency is influenced; the embodiment is based on multiple experiments, and results in that the torque error and the use efficiency are balanced when the speed is reduced to 50% of the initial speed.
In yet another alternative embodiment, the secondary speed may be 10% of the initial speed. The second speed is used to achieve the second torque accurately, and therefore, a smaller speed is taken than the first speed to achieve a higher torque accuracy.
In yet another alternative embodiment, the threaded fastener may be a screw for fastening a bicycle axle.
Example two
A computer storage medium storing computer instructions which, when invoked, perform steps in a method of controlling a threaded fastener tightening apparatus according to embodiment one.
EXAMPLE III
A tightening apparatus for carrying out the steps in the control method of a threaded fastener tightening apparatus according to embodiment one.
The disclosure of the embodiments of the present invention is only for the purpose of illustrating the preferred embodiments of the present invention, and is not to be construed as limiting the invention; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those skilled in the art; the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the spirit and scope of the technical solutions of the embodiments of the present invention.
Claims (9)
1. A control method of a threaded fastener tightening device comprises a tightening head, a motor, a torque sensor and a speed reducer, wherein the motor drives the tightening head to rotate to tighten a threaded fastener; characterized in that the method comprises:
monitoring the number of rotation turns of the tightening head after the tightening head starts to screw the threaded fastener into the fastened object, and screwing the threaded fastener into the fastened object by the tightening head at a constant initial speed;
when the number of rotation turns of the tightening head reaches a preset number of turns, controlling the speed reducer to reduce the rotation speed of the tightening head to a first speed, and triggering the torque sensor to detect and monitor the output torque of the motor;
when the output torque of the motor reaches a first torque, controlling the speed reducer to reduce the rotation speed of the tightening head from the first speed to a second speed;
when the output torque of the motor reaches a second torque, controlling the motor to stop; the second torque is greater than the first torque.
2. The control method according to claim 1, wherein the first speed and/or the first torque are determined according to a threaded fastener tightening model corresponding to a preset delay period and a model parameter of the threaded fastener.
3. The control method according to claim 2, wherein the delay period is a period between a start when the number of rotations of the tightening head reaches a preset number of rotations and an end when the reduction gear starts to reduce the rotation speed of the tightening head to the first speed.
4. The control method according to claim 1, characterized in that the first torque is 75% of the second torque.
5. The control method according to claim 1, characterized in that the first speed is 50% of the initial speed.
6. The control method according to claim 1, characterized in that the second speed is 10% of the initial speed.
7. The control method of claim 1, wherein the threaded fastener is a screw for fastening a bicycle axle.
8. A tightening apparatus characterized by being used to execute the steps in the control method of the threaded fastener tightening apparatus according to any one of claims 1 to 7.
9. A computer storage medium storing computer instructions which, when invoked, perform the steps in the method of controlling a threaded fastener tightening apparatus according to any one of claims 1-7.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211491176.2A CN115816355A (en) | 2022-11-25 | 2022-11-25 | Control method of threaded fastener tightening device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211491176.2A CN115816355A (en) | 2022-11-25 | 2022-11-25 | Control method of threaded fastener tightening device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN115816355A true CN115816355A (en) | 2023-03-21 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202211491176.2A Pending CN115816355A (en) | 2022-11-25 | 2022-11-25 | Control method of threaded fastener tightening device |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN115816355A (en) |
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2022
- 2022-11-25 CN CN202211491176.2A patent/CN115816355A/en active Pending
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