JP4460926B2 - Torque wrench for tightening inspection - Google Patents

Description

  The present invention relates to a tightening inspection torque wrench for inspecting whether or not a tightened bolt is tightened with a predetermined torque value by tightening the bolt.

  Generally, bolts (screws), nuts, etc. are tightened with a predetermined torque. As a method for inspecting whether or not a bolt being tightened is actually tightened with a predetermined torque value, a torque wrench is used. A method for tightening a bolt to be inspected (inspected bolt) with a torque wrench is known.

In this tightening inspection method, as one of the methods for determining the tightening torque value, the moment when the bolt to be inspected rotates during tightening, and the torque value indicated by the torque wrench at this time is determined as the tightening torque. (Patent Document 1).
Japanese Unexamined Patent Publication No. 6-137975

  When tightening a bolt with a torque wrench using the tightening inspection method, if the torque applied when operating the torque wrench is not constant due to the level of proficiency of the inspector operating the torque wrench, the torque wrench operating speed should be set appropriately. In some cases, it could not be performed at a high speed, which could cause false detection.

  In addition, when tightening the bolt, the torque rise characteristics change in a complex manner due to the influence of the condition of the seating surface where the bolt or nut is in contact with the member to be fastened, the situation of the threaded part, etc. There is a risk that it cannot be confirmed accurately.

  The present invention has been made in view of the above-described conventional problems, and is capable of inspecting the tightening torque of the bolt (screw) and the nut without being affected by the situation in which the bolt (screw) and the nut are tightened. We intend to provide a torque wrench for inspection.

The structure which realizes the object of the present invention includes a lever portion for tightening operation, a head portion provided at a tip portion of the lever portion and attached to an inspection fastening body such as a bolt, and the tightening of the inspection fastening body. Based on detection information from the torque sensor and the angular velocity sensor, and the inspection fastening based on the torque sensor that detects the torque generated during the rotation, the angular velocity sensor that detects the angular velocity of the lever portion that accompanies the rotation operation of the lever portion A tightening inspection torque wrench having a determination means for determining a torque value at the time of movement of the inspection fastening body of the body as a tightening inspection torque value and displaying the torque value on a display unit; The rising gradient of the rotation angle based on the detection information of the angular velocity sensor with respect to the torque based on the information is continuously greater than a predetermined rising gradient by a plurality of times. A first condition determination unit determines that the inspection fastener began to move into engagement, the torque value based on the detection information of the torque sensor is decreased temporarily above a predetermined value, and the torque value is reduced temporarily higher than a predetermined value A second condition determination unit that determines that the inspection fastening body has started to move when the angular velocity of the angular velocity sensor is greater than or equal to a predetermined value set in advance, and the torque value based on detection information of the torque sensor when the torque value changes by a predetermined value A third condition determining unit that determines that the inspection fastening body has started to move when the rotation angle based on the detection information of the angular velocity sensor exceeds a preset threshold angle value, and the first condition determining unit and the second condition determining unit If any one of the conditions of the part and the third condition determination part is satisfied, the tightening inspection torque value of the inspection fastening body is displayed on the display part.

In the above configuration, when the condition of the first condition determination unit is satisfied, the torque value obtained by the torque sensor to obtain the rising gradient of the first rotation angle is set as the tightening inspection torque value, when the condition of the second condition determination unit is satisfied, the torque value at which the torque value when the torque value is reduced temporarily higher than a predetermined value is turned to decrease and the additional-turning test torque value, said first When the condition of the three condition determination unit is satisfied, when the torque value increases and exceeds the threshold angle value, the torque value at the threshold angle value is set as the tightening inspection torque value, and the torque value decreases. When the threshold angle value is exceeded, the torque value when the torque value starts to decrease can be set as the tightening inspection torque value .

  As described above, according to the present invention, when the first condition determination unit indicating a general tightening situation in which the rotation angle increases as the torque increases, the tightening tightening causes an inspection fastening body such as a bolt. The second condition determination unit based on the movement of the decrease of the torque value and the increase of the angular velocity can determine the movement of the inspection fastening body from different viewpoints. However, even when the torque change is small, the second condition determination unit also rotates. It is determined that it is not. However, the third condition determination unit determines that the inspection fastening body has started to move when the rotation angle at that time exceeds the threshold angle value even if the torque value is slightly changed. It is possible to make a reliable determination without overlooking the movement of the inspection fastening body such as a bolt, and the torque value at that time can be displayed on the display unit.

  1 to 4 show an embodiment of the present invention.

  1 is a flowchart showing the operation of the inspection process of the tightening inspection torque wrench, FIG. 2 is a diagram for explaining the conditions of the flowchart shown in FIG. 1, and FIG. 3 is a block diagram showing the electrical configuration of the tightening inspection torque wrench. 4 and 4 are external views of the tightening inspection torque wrench of the present embodiment.

  First, the mechanical configuration of the tightening inspection torque wrench of this embodiment will be described with reference to FIG.

  The tightening inspection torque wrench 1 has a head portion 3 attached to the distal end side of a tube-shaped lever portion 2 having a predetermined length. The head portion 3 has a wrench shape at the tip, but may be of a type having a square shaft to which the socket is replaceably attached. A strain gauge 4 for electrically detecting torque is affixed to the head unit 3, and a detection signal detected by the strain gauge 4 is output to an arithmetic device 5 with a display unit.

  Further, the lever portion 2 is provided with an angular velocity sensor 6 using a vibrating gyroscope composed of a piezoelectric element or the like, and a bolt (screw) or a nut 7 (hereinafter referred to as an inspection fastening body) by tightening the bolt. Since the lever portion 2 is rotated when is rotated, the angular velocity sensor 6 detects the rotation of the lever portion 2, that is, the rotation of the inspection fastening body 7. A detection signal from the angular velocity sensor 6 is output to the arithmetic unit 5.

  As shown in FIG. 3, the arithmetic unit 5 amplifies a detection signal from the strain gauge 4 with an amplifier 51a, digitally converts it with an A / D converter 52a, and obtains a torque value from the arithmetic unit 53 comprising a CPU. input. Further, the detection signal from the angular velocity sensor 6 is amplified by the amplifier 51b, converted into a digital signal by the A / D converter 52b, and inputted to the calculation unit 53 comprising the CPU for obtaining the angular velocity (ω) and the rotation angle (θ). .

  The calculation unit 53 calculates a torque value and an angle based on torque value conversion data and angle conversion data stored in advance in the ROM 56, and displays these calculation results on the display unit 54 provided in the outer case of the calculation device 5. Let Also, operation switches 57 are attached to the exterior case so that various settings, operations such as turning on and off the power, and the like can be performed.

  On the other hand, in the calculation part 53, the discrimination | determination process which discriminate | determines whether the retightening test | inspection was performed appropriately is performed, and when it performs correctly, the green LED of the alerting | reporting part 55 will be lighted and it will be appropriately If not executed, the red LED of the notification unit 55 is blinked to notify the operator. In addition, a buzzer is sounded in conjunction with the lighting and flashing of these LEDs to notify the end of the determination.

  The tightening inspection determination processing by the arithmetic unit 53 will be described below based on the flowchart shown in FIG. 1 and the determination conditions shown in FIGS. 2 (a), (b), (c), and (d).

  In order to perform the tightening inspection, when the head 3 is mounted on the inspection fastening body 7 such as a bolt and the lever portion 2 is rotated in the tightening direction, the strain gauge 4 starts outputting the detection signal. Processing starts. Note that a timer for determining abnormality is also started simultaneously with the start of the determination process.

  When the discrimination process starts, first, condition 1 is checked in S1.

  As shown in FIG. 2A, the condition 1 is based on the characteristic curve L1 between the angle (θ) obtained by the angular velocity sensor 6 and the torque value (T) obtained by the strain gauge 4. If the rising slope of the angle (dθ1 / dT) with respect to the increase is calculated and the rising slope of this angle is larger than the preset threshold value Δ, then the rising slope (dθ2 / dT) of the next angle is subsequently set from the threshold value Δ. Is also compared. Here, if the rising gradient (dθ2 / dT) of the angle compared with the second time is smaller than the threshold value, the lever portion 2 is actually rotated only by the backlash of the torque wrench 1 and the bending of the lever portion 2, etc. Determines that the inspection fastening body 7 is not moving, determines that the condition 1 is not satisfied at the present time, and proceeds to S2. Of course, if the first ascending gradient (dθ1 / dT) is smaller than the threshold value Δ, it is determined that the inspection fastening body 7 is not actually moving, and it is determined that the condition 1 is not satisfied at the present time, and S2 Proceed to

  On the other hand, if the rising gradient (dθ2 / dT) of the angle compared with the second time is larger than the threshold value Δ, the rising gradient of the first and second angles is larger than the threshold value twice in succession. It is determined that the body 7 has started to move, and the process proceeds to S5 where the torque value is displayed on the display unit 54 and stored in the ROM 56. At this time, the tightening inspection torque value displayed on the display unit 54 is the initial torque value obtained by the strain sensor 4 in order to obtain the first angle increase gradient.

  In the present embodiment, the angle increase gradient increases by 5 digits (in the case of a tightening inspection torque wrench with a measurement range of 4 to 20 N · m, 0.1 N · m in terms of torque value). It is the ratio of the angle between.

  Next, when the condition 1 cannot be satisfied, the condition 2 is checked in S2.

  When a torque wrench is attached to the inspection fastening body 7 such as a bolt and the lever portion is pulled with force applied in the tightening direction, and the behavior of the inspection fastening body 7 before and after starting to move is observed, Since the state shifts to the state, as shown by the characteristic curves L2 and L3 shown in FIG. 2B, the movement of the inspection fastening body 7 suddenly becomes smooth and the torque wrench starts to turn suddenly. It has the property of starting to decrease.

  Condition 2 is that the torque value decrease is equal to or greater than a predetermined value as indicated by a characteristic curve L2 in FIG. 2B, and the angular velocity ω is equal to or greater than a predetermined value as indicated by a characteristic curve L3 in FIG. In this case, it is determined that the inspection fastening body 7 such as a bolt has actually rotated.

  That is, in condition 1, although the inspection fastening body 7 such as a bolt actually starts to move, it is not determined that the inspection fastening body 7 has started to rotate unless the rotation angle is somewhat large. Focusing on the behavior when the inspection fastening body 7 starts to move due to tightening, the angle rising gradient of condition 1 is not included in the requirements, and the behavior accompanying the movement of the inspection fastening body 7 such as a bolt is focused on. Judgment can be made in line with the fact that the inspection fastening body 7 has actually moved.

  In this embodiment, the torque value to be reduced under condition 2 is 4 digits (in the case of a torque wrench for tightening inspection with a measurement range of 4 to 20 N · m, 0.08 N · m in terms of torque value) or more, and the angular velocity is 3 digits (0.55 ° / s) or more.

  If this condition 2 is satisfied in S2, the displacement point at which the characteristic curve L2 turns the torque value to the decreasing side is set as the tightening inspection torque value, and is displayed on the display unit 54 in S5.

  If the condition 2 is not satisfied, the process proceeds to S3 and the condition 3 is checked.

  Since the condition 2 described above requires a torque decrease of a predetermined value or more, the inspection fastening body 7 such as a bolt may actually start to move even if the torque decrease value is not less than the predetermined torque decrease value.

Therefore, in condition 3, as shown in FIGS. 2C and 2D, the angle (θ) calculated based on the detection signal of the angular velocity sensor 6 when the torque value slightly changes (ΔT) is set in advance. If it is greater than or equal to the threshold angle θ4, it is determined that the inspection fastening body 7 such as a bolt has actually started moving. Here, FIG. 2 (c) shows a case where the torque value changes by ΔT under a situation where the torque increases. When the threshold angle θ4 is reached, it is determined that the rotation is started and the torque value (peak) at that time is determined. Value) is used as the tightening inspection torque and displayed on the display unit 54. Further, as shown in FIG. 2 (d), when the rotation angle when the torque when the torque value starts to decrease decreased ΔT was over threshold angle θ4 is the torque value of the displacement points begin to decline The tightening inspection torque is displayed on the display unit 54.

  In the present embodiment, the torque change ΔT is 10 digits (in the case of a tightening inspection torque wrench with a measurement range of 4 to 20 N · m, 0.2 N · m in terms of torque value) or less.

  By providing the condition 3 as described above, when the lever portion 2 of the torque wrench 1 is pulled in the tightening direction, the inspection fastening body 7 actually starts to move. For example, the bolt and the member to be fastened come into contact with each other. If the bolt has a strong influence on the seat and the bolt does not rotate smoothly, the decrease in the torque value cannot be cleared under condition 2 without exceeding the predetermined value, but the bolt has actually started to move. If the rotation angle clears the threshold angle θ4 with the change ΔT, the condition 3 is satisfied and the tightening inspection torque can be obtained.

  If the condition 3 is satisfied in S3, the process proceeds to S5 to display the tightening inspection torque value on the display unit 54.

  If it is determined in S3 that the condition 3 is not satisfied, the process proceeds to S4.

  Since the determination process of the above-described conditions 1, 2 and 3 of S1 to S3 is executed in a short time when the tightening inspection is started, each step of S1, S2 and S3 is not possible at the initial time ( NO) is usually determined, and the routines S1 to S3 are repeatedly executed. As the tightening progresses, the torque value, the angle, and the angular velocity increase. The tightening inspection of the fastening body 7 ends.

  When the timer started with the start of the discrimination process reaches the set time by repeating the routines S1 to S3, a tightening inspection error has occurred in S4, or the tightening force is completely insufficient and torque is applied. It is determined that an abnormality such as a failure or a failure has occurred, the abnormality occurrence is displayed on the display unit 54, a warning sound is generated on the notification unit 55, and the process ends.

  On the other hand, when any one of the above conditions 1 to 3 is satisfied and the tightening inspection torque value is displayed, and when the tightening inspection itself is finished with this inspection fastening body 7, the switch 57 is finished. When the switch is turned off, it is determined that the re-measurement is not performed in S6, and the process is terminated. However, when another tightening inspection of another inspection fastening body is performed, the head 3 is attached to the other inspection fastening body as it is, and the lever If the part 2 is pulled in the tightening direction, the above-described determination process is executed in the same manner.

The flowchart which shows embodiment of the torque wrench for tightening inspection by this invention. The figure explaining the conditions 1-condition 3 of FIG. The block diagram which shows embodiment of the electrical structure of the torque wrench for tightening inspection by this invention. 1 is an external view showing an embodiment of a torque wrench for tightening inspection according to the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Torque wrench for retightening inspection 2 Lever part 3 Head part 4 Strain gauge 5 Arithmetic device 51a, 51b Amplifier 52a, 52b A / D converter 53 CPU
54 Display unit 55 Notification unit 56 ROM
57 Switches 6 Angular velocity sensor 7 Bolt (Inspection fastening body)

Claims (4)

A lever portion for tightening operation, a head portion provided at a tip portion of the lever portion and attached to an inspection fastening body such as a bolt, and a torque sensor for detecting torque generated when the inspection fastening body is tightened And an angular velocity sensor that detects an angular velocity of the lever portion accompanying the rotation operation of the lever portion, and detection information from the torque sensor and the angular velocity sensor, when the inspection fastening body starts to move. In the tightening inspection torque wrench having a determination means for determining the torque value as the tightening inspection torque value and displaying the torque value on the display unit,
The determination means starts moving the inspection fastening body when the rising gradient of the rotation angle based on the detection information of the angular velocity sensor with respect to the torque based on the detection information of the torque sensor is larger than a predetermined rising gradient set in advance several times. An angular velocity of the angular velocity sensor when a torque value based on detection information of the torque sensor is temporarily reduced by a predetermined value or more and the torque value is temporarily reduced by a predetermined value or more. Based on detection information of the angular velocity sensor when a torque value based on detection information of the torque sensor changes to a predetermined value, a second condition determination unit that determines that the inspection fastening body has started to move when is equal to or greater than a predetermined value set in advance A third condition determination unit for determining that the inspection fastening body has started to move when the rotation angle exceeds a preset threshold angle value; The tightening inspection torque value of the inspection fastening body is displayed on the display section when any one of the first condition determination section, the second condition determination section, and the third condition determination section is satisfied. Torque wrench for tightening inspection. When the condition of the first condition determination unit is satisfied, a torque value obtained by the torque sensor to obtain a rising gradient of a first rotation angle is used as the tightening inspection torque value. Item 6. The tightening inspection torque wrench according to Item 1. If the condition of the second condition determination unit is satisfied, that said additional-turning test torque value torque value when the torque value when the torque value is reduced temporarily higher than a predetermined value is started to decline The torque wrench for tightening inspection according to claim 1. When the condition of the third condition determination unit is satisfied, when the torque value increases and exceeds the threshold angle value, the torque value at the threshold angle value is set as the tightening inspection torque value, and the torque value decreases. The tightening inspection torque wrench according to claim 1, wherein when the torque exceeds the threshold angle value, the torque value when the torque value starts to decrease is defined as the tightening inspection torque value .

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