CN-121979007-A - Three-section control method for anti-slip tooth of screw of impact screwdriver

Abstract

The invention discloses a three-section control method for preventing sliding teeth of a screw of an impact screwdriver, and aims to solve the problem that in the prior art, the impact screwdriver is easy to slide teeth when screwing a thin plate. The technical scheme is that the three-stage control method for the anti-slip tooth of the screw driver comprises the following procedures that a first stage, an impact driver outputs according to a set rotating speed n 1 , meanwhile, whether a screw is close to a through plate is judged by collecting load current change in a motor, whether the load current is obviously reduced or not is judged according to the judgment, if so, the procedure is switched to the next stage independently, a second stage, the impact driver outputs according to the set rotating speed n 2 , n 2 is smaller than n 1 , whether the screw is close to screwing is judged by collecting load current change in the motor, whether the load current is increased or distributed according to a specific waveform is judged according to the judgment, if so, the procedure is switched to the next stage independently, and a third stage, the impact driver outputs according to a set pulse mode.

Inventors

• XU XIAO
• WANG HENG
• XU RUI
• TU ZHONGYANG
• DAI XIUBO

Assignees

• 华丽电器制造有限公司

Dates

Publication Date

20260505

Application Date

20260209

Claims (8)

1. 1. A three-stage control method for preventing the screw from being slipped by an impact screwdriver is characterized by comprising the following procedures of outputting the impact screwdriver according to a set rotating speed n 1 , judging whether the screw is close to a penetrating plate or not, if so, automatically switching the procedure to the next stage, outputting the impact screwdriver according to the set rotating speed n 2 , wherein n 2 is smaller than n 1 , judging whether the screw is close to tightening or not, and if so, automatically switching the procedure to the next stage, and outputting the impact screwdriver according to a set pulse mode.
2. 2. The method of claim 1, wherein the determining whether the screw is approaching the through plate is based on a change in load current in the motor, and if the load current is significantly reduced, the approaching to the through plate is indicated.
3. 3. The three-stage control method for preventing the screw from being slipped by an impact screwdriver according to claim 1, wherein the basis for judging whether the screw is close to being screwed is that the load current change in the motor is collected, and if the load current is obviously increased or distributed according to a specific waveform, the screw is indicated to be close to being screwed.
4. 4. A three-stage control method for an impact driver to screw in a non-slip dental unit according to claim 3, wherein when the impact driver is in a plasterboard/wood gear, the screw is indicated to be approaching tightening if the load current increases significantly.
5. 5. The method for controlling an anti-slip tooth for a screw driver according to claim 3, wherein when the impact driver is in a thick iron gear, if the load current is distributed in a specific waveform, the impact driver is indicated to be in an "impact state" and the screw is close to being screwed.
6. 6. The three-stage control method for preventing the screw from being slipped by an impact screwdriver machine according to claim 5, wherein the detection program for detecting whether the impact screwdriver is impacted is characterized in that a current detection module in a main control chip detects that a current sampling value changes, judges whether current is in an ascending or descending trend, further detects whether an ascending stage meets a detection time window when the ascending trend is detected, judges that ascending detection is successful when the ascending trend is detected, switches to detect a descending trend at the moment, judges whether current is in the descending trend, judges whether the descending stage meets the detection time window if the descending trend is met, switches to detect the ascending trend if the descending detection is successful when the condition is detected, sets a threshold value for each detection time window, switches to detect the detecting trend if the condition is met, overturns, returns to an initial detection stage until all detection pairs are met, and judges to be in an 'impact state'.
7. 7. The method of claim 1, wherein when the impact driver is in a gypsum board/wood board gear, n 1 is 1400, the corresponding duty cycle is 35%, n 2 is 1000, the corresponding duty cycle is 25%, and in the pulse mode, the corresponding duty cycle is 50%, and the pulse frequency is 2 times/sec.
8. 8. The method of claim 1, wherein when the impact driver is in a thick iron gear, n 1 is 3700, the corresponding duty cycle is 94%, n 2 is 1800, the corresponding duty cycle is 45%, and in the pulse mode, the corresponding duty cycle is 50%, and the pulse frequency is 2 times/sec.

Description

Three-section control method for anti-slip tooth of screw of impact screwdriver Technical Field The invention relates to a control method of an impact screwdriver, in particular to a three-section control method for preventing a screw from slipping of the impact screwdriver. Background Compared with a conventional electric drill, the impact screwdriver has the core advantages that a special impact module is integrated inside, the impact module can adaptively switch two working states according to the load amplitude born by an output shaft so as to adapt to the torque requirements of different working situations, when the output shaft is in a low-load working condition (such as screwing in an idle screw, fastening materials with low hardness such as wood and plastic, and the like), the impact module keeps a locking or synchronous transmission state, can stably transmit the output energy from a main shaft to realize continuous linear torque output, the working mode is defined as a non-impact output state, and when the output shaft encounters a high-load working condition (such as screwing in the screw to a mechanical limit or the working of relatively high-hardness materials, dismounting the rust screw, and the like), the impact module releases the locking and enters an intermittent transmission state, intermittently transmits the output energy from the main shaft so that the output shaft intermittently outputs high-strength pulse torque (energy) to overcome high-load resistance effectively, and the working mode is defined as an impact output state. In the actual operation process, particularly when the self-tapping screw is used for tapping into plates such as aluminum profiles, gypsum boards and iron plates, the self-tapping screw has obvious step-change characteristics on the load born by the self-tapping screw in different tapping stages, and the self-tapping screw can be particularly divided into three continuous operation stages, wherein the first stage is the initial tapping stage of the screw, the self-tapping screw gradually cuts (or grinds) into the plates, the friction resistance of the plate to the screw and the extrusion resistance are synchronously and linearly increased along with the continuous increase of the tapping depth, the output power of the corresponding impact screwdriver is also linearly increased along with the increase of the friction resistance to match the load, the smooth tapping is ensured, the second stage is the approaching and penetrating stage of the screw, the self-tapping screw continuously penetrates through the plates gradually, the wrapping force and the resistance of the plate to the screw are rapidly attenuated until the screw completely penetrates through the plates, the load born by the screw is reduced to an extremely low level at the moment, the screw is almost unloaded, the screw is driven to continue screwing in, the third stage is the tightening and the self-tapping screw penetrates through the plates, the nut or the matched nut starts to abut against the surface of the plate, the screwdriver continuously outputs torque along with the continuous impact, the tightening load born by the screw is rapidly increased until the preset tightening strength reaches the preset tightening strength. The loads of the first stage and the second stage are relatively low no matter what kind of plate is used for screwing, and the switching logic of the two working states of the impact screwdriver is combined, so that the loads generated by the two stages are below the non-impact trigger threshold value of the impact screwdriver, and therefore the impact screwdriver always maintains a non-impact output state, and a larger gap exists in the third stage according to the different materials of the plates, such as on a wood plate, a gypsum plate and a thin aluminum alloy plate, even if the load generated by the third stage cannot break through the threshold value of 'impact', the load of the screw in the third stage is rapidly increased on a thicker iron plate, and the impact trigger threshold value of the impact screwdriver is rapidly exceeded, so that the impact screwdriver is switched to the impact output state. The two typical sliding teeth problems are easily caused by the stepwise load change, namely, firstly, in the second stage, the output power of the impact screwdriver is still maintained at a higher level in the first stage due to the rapid reduction of the plate resistance, the output shaft drives the self-tapping screw to idle or rotate at a higher speed, excessive friction and engagement failure are generated between screw threads and plate threads, so that the sliding teeth are caused, secondly, in the third stage, the load is rapidly increased, when the plate is a middle-low-strength plate, the material can be structurally damaged to cause the sliding teeth due to the material characteristics, and when the plate is a high-strength plate such as a thick iron plate, th