Tightening tool with built-in double groups of torque sensors and calibration-free method

Abstract

The invention relates to the field of tightening and locking, in particular to a tightening tool with two built-in torque sensors and a verification-free method.The tightening tool further comprises a dynamic torque sensor and a static torque sensor, a power device is arranged on the static torque sensor, and counter-acting force provided by an external source is transmitted to the power device through the static torque sensor; the power device provides torsion for the output end through the dynamic torque sensor; in order to solve the problem that the torsion is abnormal but not known, a new detection mode is used, the detection mode is that more than two torque sensors are used for respectively measuring the torque on the power device and the torque on the output end, and then the two torque values are compared, so that the torsion is obtained. If the torque is outside the threshold value range, the problem that the torque accuracy is reduced exists on the power device or the output end, and according to the mode, the effect of real-time monitoring is achieved, and therefore the problem that the torque is abnormal and not known is solved.

Description

Technical Field

[0001] The invention relates to the field of tightening and locking, and in particular to a tightening tool with built-in double-group torque sensors and a calibration-free method. Background Art

[0002] Electric screwdriver calibration is to use a torque measuring instrument to ensure the accuracy of the electric screwdriver when applying torque.

[0003] There are generally two situations for calibration. The first is that workers must use a torque measuring instrument to calibrate the electric screwdriver before work that day. The other condition for electric screwdriver calibration is that the working time of the electric screwdriver has met the prescribed time requirement. The latter time requirement is an estimate. When the electric screwdriver is manually calibrated using a torque measuring instrument and before the prescribed time requirement is met, the accurate value of the electric screwdriver exceeds the problem, and the products made during this time period will have defects. Summary of the invention

[0004] To solve the above problems, the present invention provides a tightening tool with a built-in dual-group torque sensor, which provides a means for detecting the torque of the output end and the electric screwdriver, and solves the problem of abnormal torque being unknown by judging the difference between the two torque values.

[0005] To achieve the above-mentioned purpose, the technical solution adopted by the present invention is: a tightening tool with a built-in dual-group torque sensor, comprising a main body, a power device is arranged in the main body, and an output end connected to the power device, characterized in that it also includes a dynamic torque sensor and a static torque sensor, the power device is arranged on the static torque sensor, the reaction force provided by an external source is transmitted to the power device through the static torque sensor, and the power device provides torque to the output end through the dynamic torque sensor.

[0006] Beneficial effects of the present invention:

[0007] 1. In order to solve the problem of unknown torque abnormality, the present invention uses a new detection method. This detection method uses two or more torque sensors to measure the torque on the power device and the torque on the output end respectively, and then compares the two torque values. If they are outside the threshold range, it indicates that there is a problem in the power device or the output end that causes the torque accuracy to decline. According to this method, the effect of real-time monitoring is achieved, thereby solving the problem of unknown torque abnormality.

[0008] 2. At the same time, this comparison method can also verify whether the torque sensor has a problem of declining detection effect. That is to say, when the detection source of one of the torque sensors has reached the replacement requirements, its detection result is inaccurate. In order to make the torque output at the output end reach the threshold, the output end or the power device will continue to work in an abnormal state, which makes the torque data detected by the other torque sensor abnormal.

[0009] 3. In addition, the power device can improve the detection accuracy of the output end by connecting the dynamic torque sensor to the output end. That is to say, it does not need to go through multi-stage transmission. Therefore, part of the torque caused by multi-stage transmission is consumed, so that the problem of inaccurate detection accuracy can also be improved. Then, the torque transmission path obtained by the existing torque sensor is: screwdriver-planetary reducer-torque sensor, and the dynamic detection sensor directly detects the torque on the output end. Therefore, the shortening of the detection path makes the control of the power device more timely. In other words, the delay in the control of the power device is reduced.

[0010] The static torque sensor consists of a connecting structure and a first resistance strain gauge. The middle part of the connecting structure is a plurality of spaced-apart connecting plates. The first resistance strain gauge is arranged on the connecting plate. The connecting structure is made of an elastic material with a rebound effect. The advantage of this design is that the middle area of ​​the connecting structure is more easily deformed when subjected to force and twisting. Therefore, the first resistance strain gauge is arranged behind the connecting plate, and any slight deformation caused by twisting will cause a change in resistance.

[0011] Specifically, the power device includes a motor and a planetary reduction box. The power device of the motor is connected to the dynamic torque sensor through the planetary reduction box. The dynamic torque sensor is connected to the bit. The motor is connected to the end of the rotating shaft inside the main body so that the motor is suspended. The above is just one of the implementation methods. According to needs, the planetary reduction box or the motor is fixed in the main body through a static torque sensor, or three static torque sensors are provided to detect the reaction force on the motor and the planetary reduction box. The former has cost advantages, and the latter is conducive to troubleshooting.

[0012] To go deeper, the main body is the shell, the static torque sensor is connected to the inner wall of the shell, and the external source is usually the hands or other equipment, such as a robotic arm. The motor and planetary reducer as the power device will exert force on the shell. The reaction brought by this external source through the shell is directly applied to the static torque sensor. This reaction force is the torque detected by the static torque sensor.

[0013] The dynamic torque sensor includes a rotating part, a brush, and a second resistance strain gauge. The rotating part is a cylindrical structure, and the first end of the rotating part is a deformation part. The second resistance strain gauge is arranged on the deformation part. The brush is located on the second end of the rotating part and is connected to the second resistance strain gauge. When the rotating part rotates in any direction and its reaction force is applied to the deformation part, the second resistance strain gauge follows the deformation of the deformation part and produces a certain distortion. The change in cross-sectional area changes the current flowing to the brush, and the brush transmits the detection signal after the resistance value changes to the processor. This design mainly highlights the application of the second resistance strain gauge. The torque is calculated by the resistance change caused by the slight deformation caused by torsion. This method has high sensitivity and accuracy and can detect slight torque changes.

[0014] The brush includes a conductive slip ring and brush wires. The conductive slip ring is sleeved on the second end of the rotating part. The conductive slip ring is concave on both sides toward the middle. The brush wires are tangential to the middle area of ​​the conductive slip ring. Under this structure, the conductive slip ring itself has a certain restraining effect on the brush wires, reducing the situation where the brush wires are detached from the conductive slip ring.

[0015] In this embodiment, two second resistance strain gauges are provided, and four conductive slip rings are provided, and two conductive slip rings are grouped as a group, respectively serving as the positive and negative electrodes of a single second resistance strain gauge;

[0016] Of course, there are isolating rings between the conductive slip rings, and the brush wires are separated by the isolating rings to avoid short circuits caused by contact between the positive and negative poles.

[0017] It also comprises an insulating sleeve, on which the conductive slip ring and the isolating ring are located, and the insulating sleeve is sleeved on the second end of the rotating part.

[0018] The above does not further limit the number of brush wires and conductive slip rings, and the number can be selected according to the needs; of course, the number of second resistance strain gauges can also be multiple, and the use is not limited to 2.

[0019] Taking into account the generation of static electricity at the output end, a grounding brush ring is also included. The grounding brush ring is sleeved on the rotating part. A part of the brush wire is connected to the grounding brush ring. The static electricity on the output end is directly led out through the grounding brush ring, forming an effect of removing static electricity.

[0020] The utility model also comprises a fixing frame, on which the brush wires are fixed, and the brush wires are projected outwards at an angle.

[0021] In addition, the surfaces of the brush wires, conductive slip rings and grounding brush rings are coated with wear-resistant conductive coatings, which improves the wear resistance and extends the service life of the brushes.

[0022] The deformation part is made of rubber material. When the deformation part is subjected to periodic torsion, fatigue or cracks will occur in the material. After using dual torque sensors, through numerical comparison, when a problem occurs in the deformation part of any torque sensor, the problem can be detected through the other torque sensor.

[0023] Specifically, the inner end of the screwdriver bit is connected to the first end of the rotating member, and the second end of the rotating member is connected to the output shaft of the planetary reduction box.

[0024] Preferably, the main body is also provided with a warning alarm and a control circuit board. The values ​​of the dynamic torque sensor and the static torque sensor are directly input into the control circuit board, and the processor in the control circuit board is responsible for the comparison. When the difference between the static torque sensor and the dynamic torque sensor is greater than the preset value, an alarm will be automatically sounded. In this way, the daily calibration process can be avoided, the operation process can be optimized, and the operation efficiency can be improved.

[0025] Of course, a display screen showing the torque value can also be provided on the main body for manual comparison.

[0026] The above-mentioned control circuit board and processor are all existing technologies, and their structures are not described in detail.

[0027] A method for free calibration of a tightening tool, characterized by comprising:

[0028] S1, a dynamic torque sensor is set on the output end, and the torque on the output end is collected by the dynamic torque sensor;

[0029] S2, setting the power device on the static torque sensor, and collecting the reaction force on the output through the static torque sensor;

[0030] S3, the processor in the control circuit board collects the torque values ​​from the static torque sensor and the dynamic torque sensor and compares them.

[0031] S4, when the difference between the values ​​exceeds the threshold range, the processor determines that the device is abnormal, controls the circuit board to turn on the alarm circuit, and the alarm emits a buzzer sound.

[0032] Under this method, the daily verification process can be eliminated, the operation process can be optimized, and the operation efficiency can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a perspective view of the present invention.

[0034] Figure 2 It is a cross-sectional view of the present invention.

[0035] Figure 3 yes Figure 2 An enlarged schematic diagram of point A.

[0036] Figure 4 It is a three-dimensional diagram of the present invention after removing the outer shell.

[0037] Figure 5 is a perspective view of a dynamic torque sensor.

[0038] Figure 6 yes Figure 5 Stereoscopic image after removing the brush wire and isolation ring.

[0039] Figure 7 is a three-dimensional diagram of a static torque sensor. DETAILED DESCRIPTION

[0040] A tightening tool with a built-in dual-group torque sensor comprises a body 1, a power device is arranged in the body 1, and an output end connected to the power device, and further comprises a dynamic torque sensor 3 and a static torque sensor 4, wherein the power device is arranged on the static torque sensor 4, and the reaction force provided by an external source is transmitted to the power device through the static torque sensor 4, and the power device provides torque to the output end through the dynamic torque sensor 3.

[0041] Beneficial effects of the present invention:

[0042] 1. In order to solve the problem of unknown torque, the present invention uses a new detection method. This detection method uses two or more torque sensors to measure the torque on the power device and the torque on the output end respectively, and then compares the two torque values. If they are outside the threshold range, it indicates that there is a problem in the power device or the output end that causes the torque accuracy to decline. According to this method, the effect of real-time monitoring is achieved, thereby solving the problem of abnormal torque not being known.

[0043] 2. At the same time, this comparison method can also verify whether the torque sensor has a problem of declining detection effect. That is to say, when the detection source of one of the torque sensors has reached the replacement requirements, its detection result is inaccurate. In order to make the torque output at the output end reach the threshold, the output end or the power device will continue to work in an abnormal state, which makes the torque data detected by the other torque sensor abnormal.

[0044] 3. In addition, the power device is connected to the output end through the dynamic torque sensor 3, which can improve the detection accuracy of the output end. That is to say, it does not need to go through multi-stage transmission. Therefore, part of the torque caused by multi-stage transmission is consumed, so that the problem of inaccurate detection accuracy can also be improved. Then, the transmission path of the torque obtained by the existing torque sensor is: screwdriver 2-planetary reducer 6-torque sensor, and the dynamic detection sensor 3 directly detects the torque on the output end. Therefore, the shortening of the detection path makes the control of the power device more timely. In other words, the delay in the control of the power device is reduced.

[0045] The static torque sensor 4 is composed of a connecting structure and a first resistance strain gauge (not shown in the figure). The middle part of the connecting structure is a plurality of spaced-apart connecting plates 41. The first resistance strain gauge is arranged on the connecting plate 41. The connecting structure is made of an elastic material with a rebound effect (preferably steel). The advantage of this design is that the middle area of ​​the connecting structure is more easily deformed when subjected to force and twisting. Therefore, after the first resistance strain gauge is arranged behind the connecting plate 41, any slight deformation caused by twisting will cause a change in resistance.

[0046] Specifically, the power device includes a motor 5 and a planetary reduction box 6, and the output end is a screwdriver bit 2. The output shaft of the motor 5 is connected to the dynamic torque sensor 3 through the planetary reduction box 6, and the dynamic torque sensor 3 is connected to the screwdriver bit 2. The connecting structure is arranged between the motor 5 and the planetary reduction box 6. The motor 5 is connected to the end of the rotating shaft inside the body 1, so that the motor 5 is suspended. The above is just one embodiment.

[0047] According to the needs, the planetary reduction box 6 or the motor 5 is fixed in the main body 1 through the static torque sensor 4, or three static torque sensors are provided to detect the reaction force on the motor 5 and the planetary reduction box 6 at the same time. The former has cost advantages, and the latter is conducive to the troubleshooting of problems.

[0048] To go deeper, the main body 1 is the outer shell, the static torque sensor 4 is connected to the inner wall of the outer shell, and the external source is usually both hands or other equipment, such as a robotic arm, etc. The motor 5 and the planetary reducer 6 as the power device will exert force on the outer shell. The reaction brought by the external source through the outer shell is directly applied to the static torque sensor 4. This reaction force is the torque detected by the static torque sensor 4.

[0049] The dynamic torque sensor 3 includes a rotating member 31, a brush, and a second resistance strain gauge (not shown in the figure). The rotating member 31 is a cylindrical structure, and the first end of the rotating member 31 is a deformation portion 31a. The second resistance strain gauge is arranged on the deformation portion 31a, and the brush is located on the second end of the rotating member 31 and is connected to the second resistance strain gauge. When the rotating member 31 rotates in any direction and its reaction force is applied to the deformation portion 31a, the second resistance strain gauge follows the deformation of the deformation portion 31a and produces a certain distortion. The change in cross-sectional area changes the current flowing to the brush, and the brush transmits the detection signal after the resistance value changes to the processor. This design mainly highlights the application of the second resistance strain gauge, and the torque is calculated by the resistance change caused by the slight deformation caused by torsion. This method has high sensitivity and accuracy and can detect slight torque changes.

[0050] The brush includes a conductive slip ring 32 and a brush wire 33. The conductive slip ring 32 is sleeved on the second end of the rotating member 31. The conductive slip ring 32 is concave on both sides toward the middle. The brush wire 33 is tangential to the middle area of ​​the conductive slip ring 32. Under this structure, the conductive slip ring itself has a certain restraining effect on the brush wire 33, reducing the situation where the brush wire 33 is detached from the conductive slip ring.

[0051] In this embodiment, two second resistance strain gauges are provided, and four conductive slip rings 32 are provided, and two conductive slip rings 32 are grouped as a group, respectively serving as the positive and negative electrodes of a single second resistance strain gauge;

[0052] Of course, an isolation ring 34 is provided between the conductive slip rings 32 , and the brush wires 33 are separated by the isolation ring 34 to avoid the occurrence of a short circuit caused by contact between the positive and negative electrodes.

[0053] It also includes an insulating sleeve 36 , on which the conductive slip ring 32 and the isolation ring 34 are located, and the insulating sleeve 36 is sleeved on the second end of the rotating member 31 .

[0054] The above does not further limit the number of brush filaments 33 and conductive slip rings 32 , and the number can be selected according to the needs; of course, the number of second resistance strain gauges can also be multiple, and the use of only two is not limited.

[0055] Taking into account the generation of static electricity on the screwdriver bit 2, a grounding brush ring 35 is also included. The grounding brush ring 35 is sleeved on the second end of the rotating member 31. A portion of the brush filaments 33 are connected to the grounding brush ring 35. The static electricity on the screwdriver bit 2 is directly led out through the grounding brush ring 35, thereby forming an effect of removing static electricity.

[0056] The utility model further comprises a fixing frame, on which the brush wires 33 are fixed, and the brush wires 33 are projected outwards at an angle.

[0057] In addition, the surfaces of the brush filaments 33 , the conductive slip ring 32 , and the grounding brush ring 35 are coated with a wear-resistant conductive coating, which improves the wear resistance and prolongs the service life of the brushes.

[0058] The deformation part 31a is made of rubber material. When the deformation part 31a is subjected to periodic torsion, fatigue or cracks will occur in the material. After using dual torque sensors, by comparing torque values, when a problem occurs in the deformation part 31a of any torque sensor, the problem can be detected through the other torque sensor.

[0059] Specifically, the inner end of the screwdriver bit 2 is connected to the deformation portion 31 a of the rotating member 31 , and the second end of the rotating member 31 is connected to the output shaft of the planetary reduction box 6 .

[0060] Preferably, the main body 1 is also provided with a warning alarm and a control circuit board. The values ​​of the dynamic torque sensor 3 and the static torque sensor 4 are directly input into the control circuit board, and the processor in the control circuit board is responsible for the comparison. When the difference between the static torque sensor 4 and the dynamic torque sensor 3 is greater than the preset value, an alarm will be automatically sounded. In this way, the daily calibration process can be avoided, the operation process is optimized, and the operation efficiency is improved.

[0061] Of course, a display screen showing the torque value can also be provided on the main body 1 so as to perform the comparison manually.

[0062] The above-mentioned control circuit board and processor are all existing technologies, and their structures are not described in detail.

[0063] A method for free calibration of a tightening tool, characterized by comprising:

[0064] S1, a dynamic torque sensor 3 is set on the screwdriver bit, and the torque on the screwdriver bit is collected by the dynamic torque sensor 3;

[0065] S2, setting the power device on the static torque sensor 4, and collecting the reaction force on the output through the static torque sensor 4;

[0066] S3, the processor in the control circuit board collects the torque values ​​from the static torque sensor 4 and the dynamic torque sensor 3, and compares them.

[0067] S4, when the difference between the values ​​exceeds the threshold range, the processor determines that the device is abnormal, controls the circuit board to turn on the alarm circuit, and the alarm emits a buzzer sound.

[0068] Under this method, the daily verification process can be eliminated, the operation process can be optimized, and the operation efficiency can be improved.

[0069] The above implementation modes are merely descriptions of the preferred implementation modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary engineering and technical personnel in the field shall fall within the protection scope determined by the claims of the present invention.

Claims

1. A tightening tool with a built-in dual-group torque sensor, comprising a body, a power device disposed in the body, and an output end connected to the power device, characterized in that: It also includes a dynamic torque sensor and a static torque sensor. The power device is arranged on the static torque sensor. The reaction force provided by the external source is transmitted to the power device through the static torque sensor. The power device provides torque to the output end through the dynamic torque sensor.

2. A tightening tool with built-in dual-group torque sensors according to claim 1, characterized in that: The static torque sensor consists of a connecting structure and a first resistance strain gauge. The middle part of the connecting structure is a plurality of spaced-apart connecting sheets. The first resistance strain gauge is arranged on the connecting sheet. The connecting structure is made of an elastic material with a rebound effect.

3. A tightening tool with built-in dual-group torque sensors according to claim 1, characterized in that: The power device includes a motor and a planetary reduction box. The power device of the motor is connected to a dynamic torque sensor through the planetary reduction box. The dynamic torque sensor is connected to the output end. The motor is connected to the end of the rotating shaft inside the body so that the motor is suspended.

4. A tightening tool with built-in dual-group torque sensors according to claim 1, characterized in that: The dynamic torque sensor includes a rotating part, a brush, and a second resistance strain gauge. The rotating part is a cylindrical structure, and the first end of the rotating part is a deformation part. The second resistance strain gauge is arranged on the deformation part. The brush is located on the second end of the rotating part and is connected to the second resistance strain gauge. When the rotating part rotates in any direction and its reaction force is applied to the deformation part, the second resistance strain gauge follows the deformation of the deformation part and produces a certain distortion.

5. A tightening tool with built-in dual-group torque sensors according to claim 4, characterized in that: The brush includes a conductive slip ring and brush wires. The conductive slip ring is sleeved on the second end of the rotating member. The conductive slip ring is concave toward the middle on both sides. The brush wires are tangential to the middle area of ​​the conductive slip ring.

6. A tightening tool with built-in dual-group torque sensors according to claim 5, characterized in that: An isolation ring is also provided between the conductive slip rings, and the brush wires are separated by the isolation ring.

7. A tightening tool with built-in dual-group torque sensors according to claim 6, characterized in that: It also comprises an insulating sleeve, on which the conductive slip ring and the isolating ring are located, and the insulating sleeve is sleeved on the second end of the rotating part.

8. A tightening tool with built-in dual-group torque sensors according to claim 4, characterized in that: The utility model also comprises a grounding brush ring, which is sleeved on the rotating part, and a part of the brush wires is connected with the grounding brush ring.

9. A tightening tool with built-in dual-group torque sensors according to claim 1, characterized in that: The main body is also provided with an alarm for warning and a control circuit board. The control circuit board has a processor for comparing torque, and the control end of the processor is connected with the input end of the alarm.

10. A calibration-free method for a tightening tool with a built-in dual-group torque sensor according to any one of claims 1 to 9, characterized in that: Contains: S1, a dynamic torque sensor is set on the output end, and the torque on the output end is collected by the dynamic torque sensor; S2, setting the power device on the static torque sensor, and collecting the reaction force on the output through the static torque sensor; S3, the processor in the control circuit board collects the torque values ​​from the static torque sensor and the dynamic torque sensor and compares them. 11.S4, when the difference between the values ​​exceeds the threshold range, the processor determines that the device is abnormal, controls the circuit board to turn on the alarm circuit, and the alarm emits a buzzer sound.

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