JP2017067747A - Method for determining fastening axial force of tapping screw and display device of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for determining fastening axial force of a tapping screw on a computer monitor screen which can display the fastening axial force of the tapping screw to determine optimal fastening axial force and a display device of the same.SOLUTION: With a method for determining fastening axial force of a tapping screw, a pressure sensor 10 is disposed between a fastening member 9 and a fastened member 11 that are coupled by a tapping screw 8 to be measured and vertically arranged with a rotational torque analyzer having a screw bit 6 and a rotational torque sensor. A tapping screw 8 engaged with the screw bit 6 is inserted from above the fastened member 11 and fastening is started. Based on data from the rotational torque sensor and data from the pressure sensor 10 during a period before a female screw is broken, target fastening torque of the tapping screw and/or fastening axial force of the tapping screw is determined.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a method for determining a fastening axial force of a tapping screw and a display device therefor.

  The screw tightening axial force refers to the tightening force when tightening by turning the screw. The screw tightening axial force is determined by the torque coefficient (k) obtained from the standard bolt-nut combination. As examples of measuring the combined tightening axial force, those disclosed in, for example, registered utility model No. 3188661 and JP 2010-117334 A are known.

  The one disclosed in the registered utility model No. 3188661 relates to the name of the device “Axial force measurement sensor and axial force measurement sensor device using this sensor”, and “A male screw when a male screw member is fastened to a female screw member” In the object of the invention solution (see paragraph No. 0009 of the same publication), the object is to provide an axial force measurement sensor capable of directly measuring the axial force of a member and an axial force measurement sensor device using this sensor. An axial force measurement sensor that is disposed between the head of the male screw member and the female screw member and measures the axial force of the male screw member when the male screw member is screwed into the female screw member, the shaft portion of the male screw member A cylindrical member that is inserted through, an upper flange and a lower flange that project outward with respect to the cylindrical member and that are provided with a predetermined gap therebetween, and the upper flange. And at least one load sensor that detects a change in load as a change in resistance value, and projects downward from the lower surface of the upper flange or from the upper surface of the lower flange. A pressing element that protrudes upward and presses the load sensor, and when the male screw member is turned in the tightening direction, the cylindrical member is compressed by the head of the male screw member, and the pressing The element presses the load sensor and measures the load from the pressure element acting on the load sensor, thereby measuring the axial force of the male screw member ''. (Refer to the description of claim 1 in the scope of the above)), “Axial force measuring sensor capable of directly measuring the axial force of the male screw member when the male screw member is tightened with respect to the screw member, and this sensor In which an effect that can "be obtained axial force measuring sensor device (see the publication specification paragraph number 0020).

FIGS. 7A and 7B show an axial force measurement sensor according to the first embodiment of the idea described in the registered utility model No. 3188661 disclosed in FIG. 1 and FIG. 2 in the registered utility model No. 3188661. It is the perspective view which shows the state in which A was attached, and its sectional drawing.
7A and 7B, 101 is an axial force measurement sensor, 102 is a cylindrical member, 102a is a protrusion, 103 is a (upper) flange, 104 is a (lower) flange, 105 Is a presser, 106 is a load sensor, 107 is a lead wire, 111 is a female screw member, 111a is a female screw hole, 112 is a male screw member, 112a is a shaft portion, and 112b is a head (reference numeral) Was changed to three digits in order to clarify the prior art to the applicant of the present application).

  The disclosure of Japanese Patent Application Laid-Open No. 2010-117334 relates to the invention name “bolt axial force measuring method and bolt axial force measuring machine”, and “a bolt tightening management method that leads to prevention of bolt loosening and breakage in the field”. It is an excellent method that does not require any special skill level or high skill at any site, indoors or outdoors, and a method for measuring the axial force of a bolt that can be easily implemented by anyone, and an unprecedented simple structure The purpose of this invention is to provide a bolt axial force measuring machine having an equipment configuration capable of measuring axial force accurately, quickly and very economically for all bolt sizes ''. (See paragraph No. 0009 of the gazette specification), “When tightening in the field using bolts and nuts that penetrate the body to be fastened, the tightening bolts and nuts are not subjected to any processing. Bolt axial force detection means is placed between the body and the head of the bolt or between the body to be fastened and the nut, and nut tightening means is provided on the nut so that the tightening axial force and tightening torque are "Simultaneous measurement" and the like (see the description of claim 1 of the patent publication), "At the work site, first select three typical bolts and nuts of the body to be fastened, On the spot, the bolt axial force measuring device of the present invention is mounted on the bolt and nut, and the axial force acting on the bolt is subjected to the yield point via the elastic region of the bolt using the torque wrench or gyro wrench. The tightening test is continuously performed until the point exceeding the maximum value and the point exceeding the maximum value, which indicates the relationship of the tightening axial force to the tightening torque or the relationship of the tightening axial force to the tightening rotation angle. After that, a simple calculation is performed based on the values shown in the graph, and the target tightening torque value (referred to as torque method) that gives the target tightening axial force value in the elastic region, or the target of the elastic limit A target tightening rotation angle (referred to as torque gradient method) that gives a tightening axial force value, or a target tightening rotation angle (referred to as rotation angle method) that gives a target tightening axial force in each of the elastic region and plastic region is calculated. The tightening operation of all bolts of the body to be fastened is performed by using the target tightening torque value or the target tightening rotation angle as an index. It is possible to achieve such an effect as to "accurate tightening" (see paragraph number 0018 of the same gazette specification).

  8 (a) and 8 (b) show a bolt axial force measuring machine according to an embodiment of the invention described in JP 2010-117334 A disclosed in FIGS. 1 and 2 in JP 2010-117334 A described above. It is sectional drawing of the center hole type load meter of the volt | bolt axial force measuring machine concerning the whole block diagram and embodiment.

  8A and 8B, 201 is a bolt axial force measuring machine, 202 is a tightening bolt, 221 is a bolt head, 222 is a tightening nut, 203 is a center hole type load meter, and 204 is , Ratchet wrench, etc. 241 is a ratchet wrench head, 205 is a torque wrench or gyro wrench, 251 is a torque wrench or gyro wrench replacement head, 252 is a socket, 206 is a sensor interface, 261 and 262 are connected 207 is a core part of a load cell, 273 is a through hole, 281, 282 and 283 are strain gauges, 208 a, 208 b, 208 c and 208 d are gauge lead wires, 209 is a protective case, 215 is Personal computers, A, and B are fastened objects (the reference sign indicates that the present applicant is prior art). It was subjected to change to a three-digit number two hundred bills in order to do).

  In addition, since it is generally difficult to measure the tightening axial force of a screw, for example, the disclosure of Japanese Patent Application Laid-Open No. 06-226666 is known. The disclosure of Japanese Patent Application Laid-Open No. 06-226666 relates to the invention name “screw axial force management method and apparatus”, and “about 90% of the tightening torque is consumed by friction between the screw surface and the seat surface. For the purpose of solving the problems such as the influence of the influence, the variation of the tightening axial force is large, and the reliability of torque management is very low ... (see paragraph No. 0003 of the specification), With regard to the screw (100) to be performed, the yield point known from the calculation or the data of the same type of screw is the end point of screw tightening, and the rotational load at this yield point, that is, the torque, is 100%. In addition, the load condition of a torque at a predetermined ratio with respect to this load torque at the yield point is set as the screw tightening origin, and the axial force management of the screw (100) is controlled from the origin to the yield point, that is, the end point. (Ten 0) By controlling the rotation angle, the screw tightening is performed (see the description of claim 1 in the claims of the same publication), and so on. Even if it is done, there will be no variation in the starting point of tightening ... Friction generated between the male screw and female screw and friction generated on the screw seating surface will not always allow the screw to be tightened from a specific starting point, making it an appropriate axial force It is possible to eliminate the situation where management cannot be performed ・ ・ Tighten to the yield point and obtain a more stable axial force ・ ・ Data of the origin that owns itself, that is, the load state at the yield point The torque detection means 2 and the screw tightening means 1 are controlled on the basis of the load ratio data of the predetermined ratio, and the screw is tightened to the origin position. After reaching the origin, the screw until the yield point of the control means 4 is reached. Rotation angle of Based on the data, the rotation amount detection means 3 can be controlled to the screw tightening means 1 and the screw can be tightened to the yield point position. Therefore, the starting point of the axial force management of the screw is not varied, In addition, it is possible to accurately perform screw tightening to the yield point position, and to realize stable generation of axial force ”(see paragraph number 0007 of the publication).

  However, the axial force measurement disclosed in these registered utility model Nos. 3188661 and 2010-117334 and in Japanese Patent Application Laid-Open No. 06-226656 is both a bolt (male screw member) and a nut (female screw member). It is based on the measurement of the axial force applied to the combination, and is not related to tapping screws.

  Fastening with a tapping screw requires a certain amount of screwing torque in order to be seated (the bottom surface (seat surface) of the screw head is in close contact with the mounting member or the mounted member). It is common to use a soft material that will occur, so if too much screw tightening torque is applied after seating, too much axial force will be applied to the strength, which in turn will cause the female thread of the mating member to break, For the tapping screw, it is necessary to measure the axial force in consideration of the relationship with the member to be fastened. In other words, since the tapping screw is fastened while the screw itself is plastic tapped (Self Tapping), if the material to be fastened is a thermoplastic resin or the like, the screw tightening torque is changed by the change in the rotational speed of the screwed spindle. Changes greatly, and it is difficult to calculate axial force.

Registered Utility Model No. 3188661 JP 2010-117334 A Japanese Patent Laid-Open No. 06-226656

  Accordingly, the present invention has an object to provide a method for determining the tightening axial force of a tapping screw, which can display the tightening axial force of the tapping screw on a computer monitor screen, and determine the optimum tightening axial force, and a display device thereof. To do.

In order to solve the above-mentioned problem, the invention according to claim 1 of the present application includes at least a screw bit and a rotational torque sensor in a method for determining a target tightening torque of a tapping screw and / or a tightening axial force of the tapping screw. In the torque analyzer, place a pressure sensor between the fastening member to be fastened with the tapping screw to be measured and the fastening member, and insert the tapping screw engaged with the screw bit from above the fastening member and tighten it. The target tightening torque of the tapping screw and / or the tightening axial force of the tapping screw is determined on the basis of the data from the rotational torque sensor and the data from the pressure sensor until the internal screw breaks. To do.
The invention according to claim 2 of the present application is the method for determining the target tightening torque of the tapping screw and / or the tightening axial force of the tapping screw according to claim 1, wherein the pressure sensor is the tapping screw to be measured. It is a washer-type pressure sensor having a hole through which is inserted.
Further, the invention according to claim 3 of the present application is the method for determining the target tightening torque of the tapping screw and / or the tightening axial force of the tapping screw according to the first aspect of the invention, wherein the target tightening torque of the tapping screw is determined. Determine the tightening torque and screwing torque from the seating of the tapping screw to the female screw breakage and the female screw breaking torque by multiple measurements, and average values of the screwing torque and female screw breaking torque obtained by the multiple measurements. And the sum of the average value of the screwing torque obtained from the multiple times measurement and the standard deviation of four times the average value of the screwing torque is set as the minimum value of the target tightening torque, and the internal thread breakage obtained from the multiple times measurement The difference between the average value of the torque and the standard deviation of 4 times the average value of the female screw breaking torque is taken as the maximum value of the target tightening torque. The half of the sum of the minimum tightening torque values (1/2) is the median value of the target tightening torque of the tapping screw, and half the difference between the maximum value and the minimum value is the target tightening torque of the tapping screw. It is characterized by a tolerance of ± attached torque.
The invention according to claim 4 of the present invention is the method for determining the target tightening torque of the tapping screw and / or the tightening axial force of the tapping screw according to claim 3, wherein the target tightening of the tapping screw with ± tolerance is performed. Torque is displayed as a mathematical expression and / or a band-shaped range on the monitor screen of the computer.
The invention according to claim 5 of the present application is the method for determining the target tightening torque of the tapping screw and / or the tightening axial force of the tapping screw according to claim 3, wherein the axial force (FS) of the screw and the screw are determined. FS = (T−TTP) / uk (T is the tightening torque of the screw, uk is the demonstration individual torque coefficient, FS is the axial force (kN), and TPP is the relational expression of the tightening torque (T). On the basis of the seating point torque value), an axial force with ± tolerance is determined from the target tightening torque with ± tolerance.
Further, in the invention according to claim 6 of the present invention, in the method for determining the target tightening torque of the tapping screw and / or the tightening axial force of the tapping screw according to claim 5, the ± tensioning axial force of the tapping screw is Further, a tolerance display and / or a band-shaped range is displayed on the monitor screen of the computer.
Furthermore, the invention according to claim 7 of the present application is the method for determining the target tightening torque of the tapping screw and / or the tightening axial force of the tapping screw according to claim 6, wherein the torque value data from the rotational torque sensor is obtained. The horizontal axis indicates the axial force value data from the pressure sensor and the vertical axis indicates a band-shaped range on the monitor screen of the computer.
Further, the invention according to claim 8 of the present application is the method for determining the target tightening torque of the tapping screw and / or the tightening axial force of the tapping screw according to claim 7, wherein the mathematical expression is displayed on the monitor screen of the computer and / or Alternatively, the target tightening torque with ± tolerance of the tapping screw and the axial force with tolerance of the tapping screw displayed in a band-like range are displayed in a cross shape at the same time.
Next, an invention according to claim 9 of the present application is a display device for a target tightening torque of a tapping screw and / or a tightening axial force of a tapping screw, and a torque analyzer including at least a screw bit, a rotational torque sensor, and a computer, It consists of a pressure sensor arranged between the fastening member to be fastened with the measuring tapping screw and the material to be fastened. The tapping screw engaged with the screw bit is inserted from above the fastening member to start tightening. The data from the rotational torque sensor and the data from the pressure sensor until the female screw breaks are captured and displayed on the computer.
The invention according to claim 10 of the present application is the display device for the target tightening torque of the tapping screw and / or the tightening axial force of the tapping screw. The target tightening torque of the screw and / or the tightening axial force of the tapping screw is displayed.
The invention according to claim 11 of the present application is the method of determining the target tightening torque of the tapping screw and / or the tightening axial force of the tapping screw according to claim 1, wherein the target tightening torque of the tapping screw is determined. Is determined by multiple measurements of the tightening torque, screwing torque and female screw breaking torque from the seating of the tapping screw to the female screw breaking, and the maximum and minimum values of the tightening torque up to the obtained female screw breaking torque. The tightening torque range and the corresponding axial force range based on the demonstrative individual torque coefficient obtained from the following formula from the maximum axial force value at the maximum tightening torque value and the minimum axial force value at the minimum tightening torque value: Is a tolerance of the target tightening torque of the tapping screw.
uk = (TSmax−TSmin) / (FSmax−FSmin) (uk is the demonstration individual torque coefficient, TSmax is the maximum value of the target tightening torque (TS), TSmin is the minimum value of the target tightening torque (TS), FSmax Is the maximum axial force at TSmax (ms), FSmin is the minimum axial force at TSmin (ms))
The invention according to claim 12 of the present application is the method for determining the target tightening torque of the tapping screw and / or the tightening axial force of the tapping screw according to claim 11, wherein the tightening torque range is the target of the tapping screw. It is determined as a tolerance of the tightening torque, and a mathematical expression and / or a band-shaped range is displayed on the monitor screen of the computer.
The invention according to claim 13 of the present application is the method for determining the target tightening torque of the tapping screw and / or the tightening axial force of the tapping screw according to claim 11, wherein the torque value data from the rotational torque sensor is obtained. The axial force value data from the pressure sensor is plotted on the horizontal axis, and the axial force with a tolerance of the tapping screw is displayed in a band-shaped range on the monitor screen of the computer.
Furthermore, the invention according to claim 14 of the present invention is the method for determining the target tightening torque of the tapping screw and / or the tightening axial force of the tapping screw according to claim 13, wherein the mathematical expression is displayed on the monitor screen of the computer and / or Alternatively, the target tightening torque with ± tolerance of the tapping screw and the axial force with tolerance of the tapping screw displayed in a band-like range are displayed in a cross shape at the same time.
The invention according to claim 15 of the present application displays the target tightening torque of the tapping screw and / or the tightening axial force of the tapping screw by the determination method according to any of claims 11 to 14. A display device for the target tightening torque of the tapping screw and / or the tightening axial force of the tapping screw.

Until now, it was impossible to calculate the tightening axial force with tolerance against the target tightening torque with tolerance of the tapping screw, but it is possible to display the tightening axial force of the tapping screw on the computer monitor screen. It became.
In addition, as a result, the tightening axial force with tolerance against the target tightening torque with tolerance of the tapping screw is indicated by a cross-shaped square frame, so that the tapping screw having a certain specification is used. Both optimum torque and axial force determined from the material can be confirmed simultaneously and visually.

FIG. 1 is a schematic diagram of a method for determining a fastening axial force of a tapping screw according to the first embodiment and a screw torque analyzer 1 constituting the display device. FIGS. 2A and 2B are diagrams showing an outline of measuring the target tightening torque (TS) and axial force (FS) of the tapping screw using the torque analyzer 1. FIG. 3 shows a method of determining the tightening axial force of the tapping screw according to the first embodiment and its display device, wherein the rotational drive motor 2 has a rotational speed of 400 revolutions / minute and an outer diameter of 2.9 mm when tightening the screws. (Nominal diameter 3 mm), head outer diameter 6.7 mm, neck length 11.44 mm, pitch 1.14, torque from the torque sensor 3 in the case of using a trivalent chromate plating specification The value data and the axial force value data from the washer pressure sensor 10 are “time (ms)” on the horizontal axis, the “torque value (N · m)” from the rotational torque sensor 4 and the washer pressure sensor 10. It is a figure which shows the outline of a display displayed on the monitor screen of the said computer 7 as "axial force value (kN)" from. 4 is a graph on the monitor screen of the computer 7 as “torque value (N · m)” from the rotational torque sensor 4 and “axial force value (kN)” from the washer-type pressure sensor 10 shown in FIG. It is a figure which shows the outline which displays the said target fastening torque (TS) with tolerance and the said axial force (FS) with tolerance superimposed on the figure which shows the display outline displayed. FIG. 5 is the same as FIGS. 3 and 4, and uses the method for determining the tightening axial force of the tapping screw according to the first embodiment and its display device, and the rotational speed 400 of the rotary drive motor 2 when tightening the screw. Rotation / min, When using a tapping screw with an outer diameter of 2.9 mm (nominal diameter of 3 mm), a head outer diameter of 6.7 mm, a neck length of 11.44 mm, a pitch of 1.14, and trivalent chromate plating As for the torque value data from the torque sensor 3 and the axial force value data from the washer-type pressure sensor 10, the torque value data (N · m) is plotted on the horizontal axis and the axial force value data (kN) is plotted on the horizontal axis. It is a figure which shows the outline displayed on the vertical axis | shaft. FIG. 6 shows a method for determining the fastening axial force of a tapping screw according to the first embodiment and its display device, wherein the rotational drive motor 2 has a rotational speed of 400 revolutions / minute and an outer diameter of 2.9 mm during screw fastening. (Nominal diameter 3 mm), head outer diameter 6.7 mm, neck length 11.44 mm, pitch 1.14, torque from the torque sensor 3 in the case of using a trivalent chromate plating specification Value data and axial force value data from the washer-type pressure sensor 10, the torque value data (N · m) is on the horizontal axis, the axial force value data (kN) is on the vertical axis, and the tolerance target It is a so-called torque / axial force diagram in which the range of the axial force (FS) with tolerance is displayed on the schematic diagram showing the tightening torque (TS) by touching. FIGS. 7A and 7B show an axial force measurement sensor according to the first embodiment of the idea described in the registered utility model No. 3188661 disclosed in FIG. 1 and FIG. 2 in the registered utility model No. 3188661. It is the perspective view which shows the state in which A was attached, and its sectional drawing. FIGS. 8 (a) and 8 (b) show a bolt axial force measuring machine according to an embodiment of the invention disclosed in JP 2010-117334 A disclosed in FIGS. 1 and 2 in JP 2010-117334 A. It is sectional drawing of the center hall | hole type load meter of the bolt axial force measuring machine concerning a whole block diagram and embodiment. FIG. 9 shows how to determine the axial force value (kN) on the horizontal axis and the axial force value data (kN) on the horizontal axis using the method for determining the fastening axial force of the tapping screw according to the second embodiment and its display device. FIG. 7 is a torque / axial force diagram displayed as an axis, and in the torque / axial force diagrams corresponding to FIG. 5 and FIG. 6, a linear portion (which is between the target tightening torque minimum value and the target tightening torque maximum value); Focusing on the minimum value (TSmin) of the target tightening torque (TSmin), the maximum value of the target tightening torque (TSmax), and the minimum value of the axial force at the time of TSmin (ms) ( The target tightening torque range and the axial force range are obtained from the maximum axial force value (FSmax) at FSmin) and TSmax (ms), and the target tightening torque and axial force with ± tolerance are expressed numerically with hatching. Is.

  An embodiment for carrying out a method for determining a tightening axial force of a tapping screw and a display device thereof according to the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a schematic diagram of a method for determining a fastening axial force of a tapping screw according to the first embodiment and a screw torque analyzer 1 constituting the display device. In FIG. 1, 1 is a torque analyzer that detects the torque of a tapping screw, 2 is a rotational drive motor, 3 is a rotational torque sensor, 4 is a handle, 5 is a bit holder, 6 is a bit, 7 is A computer having a monitor screen.

  The torque sensor 3 used in the method for determining the tightening axial force of the tapping screw according to the first embodiment and the display device thereof is preliminarily incorporated coaxially into the torque analyzer 1 and is, for example, a rotational torque sensor (manufactured by Lorentz, Germany) Model DR2447 / M310) is used. That is, the bit 6 fixed to the bit holder 5 gives torque to the tapping screw at the tip thereof by the rotational drive motor 2, and at that time, the torque in the rotating state is measured by the torque sensor 3, and the torque is measured. It is comprised so that it may output to the computer 7.

2A and 2B are diagrams showing an outline of measuring the target tightening torque (TS) and axial force (FS) of the tapping screw using the torque analyzer 1. 2A and 2B, reference numeral 5 denotes the above-mentioned bit holder, 6 denotes the same bit, 8 denotes a tapping screw for measuring axial force, 9 denotes a fastening member, 10 denotes a washer-type pressure sensor, 11 Is a member to be fastened, and 12 is a support jig.
The washer-type pressure sensor 10 used in the method of determining the fastening axial force of the tapping screw according to the first embodiment and the display device thereof is a thin force sensor (model 9130B ...- 9137B of Nippon Kisler Co., Ltd., headquartered in Switzerland). Is a hollow disk washer-type pressure sensor having a hollow hole with a hole diameter of 2.7 mm to 15 mm and a thickness of 3.0 mm to 5.0 mm and an outer diameter of 8.0 to 36.0 mm. is there.
In this case, when the axial force of the tapping screw 8 is measured, the tapping screw 8 longer than the actually used tapping screw by the thickness of the washer type sensor 10 is used.

  Then, as shown in FIGS. 2A and 2B, in order to measure the axial force of the tapping screw 8 using the method for determining the fastening axial force of the tapping screw according to the first embodiment and its display device, The fastening member 9 made of SPCC material or the like having a fool hole and the fastened member 11 made of ABS resin or the like in which a pilot hole shaped hole for tapping (thread cutting) has been drilled are prepared. The washer type pressure sensor 10 is sandwiched between the fastening member 9 and the fastened member 11 and the washer type pressure sensor 10 is arranged in accordance with both holes into which the tapping screws 8 are inserted. The axial force of the tapping screw 8 is measured.

(1) Determination of Tightening Torque for Tapping Screw First, the relationship between the screw tightening torque and the axial force for a normal bolt / nut combination that is not a tapping screw is as follows.

Formula 1

However, (Equation 1) includes parameters that are very difficult to measure, such as the thread friction coefficient μ and the bearing surface friction coefficient μn, in addition to many parameters.
Therefore, the following formula is generally used for the relationship between the screw tightening torque and the axial force.

Formula 2

  T = kdF ÷ 1,000 (Formula 2) k: Torque coefficient, d: Nominal diameter of screw mm

Normally, the screw tightening torque can be easily measured using a torque wrench, but the screw tightening axial force cannot be easily measured using a special tester. The torque and axial force are measured in combination, and then the axial force corresponding to the screw tightening torque of the nominal diameter of each screw is calculated using (Equation 2).
For example, when the combination of M10 bolt and nut (nominal diameter d: 10 mm), measured torque T: 10 N · m, measured axial force F: 5,000 N, the torque coefficient (k) using (Equation 2) To decide. That is,

10N · m = k × 10mm × 5,000N ÷ 1,000
k = {10 N · m / (10 mm × 5,000 N)} × 1,000 = 0.2

  Thus, using the torque coefficient (k) determined from the combination of the M10 bolt and nut, which is a standard bolt-nut combination, for the required bolt-nut combination, for example, the M3 bolt and nut ( The axial force (F) = 1.667N at the tightening torque T = 1 N · m was obtained from the following equation (Equation 3) obtained by converting Equation 2).

Formula 3

F = (T / kd) × 1,000 (Formula 3)
= {1N · m / (0.2 × 3mm)} × 1,000 = 1,667N

  The axial force of the screw determined in this way, as described above, is the relationship between the torque and axial force in the bolt against a nut specially prepared for a standard already formed with an internal thread. It is a formula, and cannot be applied to a tapping screw that performs tightening while threading a pilot hole of a material to be fastened.

(2) Measurement and Acquisition of Torque Value Data / Axial Force Value Data Therefore, in the method of determining the fastening axial force of the tapping screw according to the first embodiment having the above-described configuration and the display device thereof, the fastening member 9 and The washer-type pressure sensor 10 is sandwiched between the fastening member 11 and the washer-type pressure sensor 10 is arranged in accordance with both holes into which the tapping screws 8 are inserted. Then, the bit 6 is attached to the tapping pin. Engage with the screw head of the screw 8 and turn on the switch of the rotary drive motor 2, and operate the handle 4 to rotate the rotary drive motor 2 at the set number of rotations, resulting in a screw stupid Screw tightening is performed using the torque analyzer 1 until (female screw breakage).

Two types of data, the torque value data from the torque sensor 3 and the axial force value data from the washer type pressure sensor 10, are obtained from the computer ( PC) 7.
In this case, the same measurement is performed a plurality of times (for example, 3 to 10 times) in order to obtain a standard deviation for taking into account measurement variations.

  FIG. 3 shows a method of determining the tightening axial force of the tapping screw according to the first embodiment and its display device, wherein the rotational drive motor 2 has a rotational speed of 400 revolutions / minute and an outer diameter of 2.9 mm when tightening the screws. (Nominal diameter 3 mm), head outer diameter 6.7 mm, under head length 11.44 mm, pitch 1.14, torque value data from the torque sensor 3 when using tapping screws with trivalent chromate plating specifications The axial force value data from the washer pressure sensor 10 is “time (ms)” on the horizontal axis, the “torque value (N · m)” from the rotational torque sensor 4 and the washer pressure sensor 10 It is a figure which shows the display outline displayed on the monitor screen of the said computer 7 as a graph as "axial force value (kN)."

  In FIG. 3, the “time (ms)” is taken on the horizontal axis, the “torque value (N · m)” graph is shown in “thin line display”, and the torque value (N · m) is shown on the left vertical axis. Then, the “axial force value (kN)” graph is displayed in “thick line display”, and the axial force value (kN) value on the right vertical axis is displayed.

  That is, the torque value from the torque sensor 3 from the start of tightening of the tapping screw 8 taken in by using the method of determining the tightening axial force of the tapping screw according to the first embodiment and its display device. Data and axial force value data from the washer-type pressure sensor 10 show changes in torque values and axial force values that change with time. In FIG. 3, the “torque value (N · m)” graph is shown. “TD” in the “thin line display” indicates screwing torque (torque required for the bottom surface of the tapping screw to reach the upper surface of the material to be fastened), and “TF” indicates internal thread breaking torque (the tapping screw causes female thread breaking). Torque), “TP” in “thick line display” of the “axial force value (kN)” graph is a seating point (a point where the bottom surface of the head of the tapping screw reaches the upper surface of the material to be fastened), “FF” Is a destructive axial clamping force (point a screw idiot by with tapping screw tightening).

In FIG. 3, the horizontal bar graph described above the right vertical axis is a histogram of the female screw breaking torque (with a normal distribution curve), and the horizontal bar graph described below the vertical axis on the right is a histogram of screwing torque ( With normal distribution curve).
As shown in FIG. 3, the “thin line display” and “torque value (N · m)” data are applied with a screwing torque (TD) gently while threading the pilot hole from the start of tightening, and the tapping screw 8 Bites into the pilot hole and becomes a high torque value. Thereafter, the screwing torque (TD) reaches the maximum tightening torque (TF), and thereafter, the torque in the idling state is reduced.

  In addition, the “axial force value (kN)” data of “thick line display” has a small screw tip diameter immediately after the start of tightening, so that torque is gently applied to the seating point (TP), and then the pilot hole is threaded. If the rotation continues while applying the required powerful torque, the axial force is generated at the start of (TP) and reaches the breaking fracture axial force (FF). After the female screw is broken, the axial force is reduced without being attracted strongly. .

(3) Determination of target tightening torque (TS) and tolerance (average value of screwing torque (TD) and female thread breaking torque (TF))
The target tightening torque for the tapping screw (“target tightening torque (TS)”) is, as is apparent from FIG. 3, a moderate torque is applied while the pilot hole is threaded from the start of tightening, and the tapping screw 8 After the screw bites into the pilot hole, the screw torque (TD) is applied and the torque value increases, and then reaches the maximum female screw breaking torque (TF). The target tightening torque (TS), which is the target of the above, is always between the screwing torque (TD) and the female screw breaking torque (TF), that is, the maximum value of the screwing torque (TD) and the female screw breaking torque (TF). Between the minimum values of.

That is, the target tightening torque (TS) takes a range of (maximum value of screwing torque (TD)) <TS <(minimum value of internal thread breaking torque (TF)).
Therefore, the maximum value of the screwing torque (TD) and the minimum value of the female screw breaking torque (TF) must be obtained. As described above, the determination of the tightening axial force of the tapping screw according to the first embodiment is performed. In the method and its display device, there are variations in the measurement of the tightening torque of the tapping screw. In consideration of this variation, the same measurement is performed a plurality of times (for example, 3 to 10 times) as described above in order to obtain the maximum value and the minimum value, and obtained by the measurement of the plurality of times (for example, 3 to 10 times). Respective average values (arithmetic average: a value obtained by dividing the sum of the measurement data of the plurality of times by the number of measurements) for the screwing torque (TD) and the female screw breaking torque (TF) are obtained.
The average value does not prevent the average value from being a geometric average in some cases.

(Necessity of tolerance)
On the other hand, for the tapping screw, as described above, a member to be fastened with a soft material that is immediately plastically deformed is used, and if the screw tightening torque is excessively applied even after seating, the internal thread breakage may occur. It can be tightened with a narrow torque range. That is, if the target tightening torque (TS) is not screwed with a torque equal to or higher than the screwing torque (TD), the target tightening torque (TS) is not seated. Therefore, the screwing torque (TD) and the female screw breaking torque (TF) have a variation (standard deviation), and the screwing torque (TD) and the female screw breaking torque (TF) are obtained even if a plurality of measurement tests are performed. Do not show the same numerical value, but they always vary.

Therefore, in order to obtain the target tightening torque (TS) with tolerance in consideration of the varied numerical values, the median value of the target housing torque (TS) is required.
(± median of target tightening torque (TS) required for tolerance determination)
The median value of a certain value in the range is half (1/2) of the sum of the maximum value and the minimum value.
Therefore, the median value of the target tightening torque (TS) having a range is half (1/2) of the sum of the female screw breaking torque (TF) which is the maximum value and the screwing torque (TD) which is the minimum value. Can be sought.

(Determining tolerance)
In the method for determining the tightening axial force of the tapping screw according to the first embodiment and its display device, in order to determine the screwing torque (TD) and the female screw breaking torque (TF) in consideration of this variation, Determine by statistical method.
Based on the theoretical statistics of statistical methods, the value of the population is 99.73% within the standard deviation of ± 3 times the median average value, so the screw torque (TD) and the female screw failure The torque (TF) also has a standard deviation of ± 3 of the average value, which is the median value of the target tightening torque (TS), by this method, but with a standard deviation of ± 3 times the average value, 100% Since it is not always possible to ensure safety, the method for determining the tightening axial force of the tapping screw according to the first embodiment and its display device take a standard deviation of ± 4 times the average value in view of safety. And

(Relationship between target tightening torque (TS), screwing torque (TD), female screw breaking torque (TF))
In order to set the range of the target tightening torque (TS) to a standard deviation of ± 4 times the average value, the minimum value of the target tightening torque (TS) is the maximum value of the screwing torque (TD), and The average value of the screwing torque (TD) and the sum of four times the standard deviation of the screwing torque (TD) (average value of the screwing torque (TD) + 4 × standard deviation of the screwing torque (TD)), and The maximum value of the target tightening torque (TS) is the minimum value of the female screw breaking torque (TF), and the difference between the average value of the female screw breaking torque (TF) and the standard deviation of the female screw breaking torque (TF) is four times. (Average value of TF−4 × standard deviation of TF).

  In other words, considering the standard deviation of the screwing torque (TD) and the female screw breaking torque (TF), the minimum value of the target tightening torque (TS) is the average value of the screwing torque (TD). The maximum value of the target tightening torque (TS) is 4 times the deviation of the female screw breaking torque (TF) to the average value of the female screw breaking torque (TF). The subtracted values are + tolerance and −tolerance, respectively. In the method of determining the fastening axial force of the tapping screw according to the first embodiment and the display device thereof, these are the values of the target fastening torque (TS) of the tapping screw. ± tolerance.

(Target tightening torque with tolerance (TS))
Target tightening torque (TS) is a tolerance with ± tolerance, with (maximum screwing torque (TD) + minimum value of internal thread breaking torque (TF)) ÷ 2 being the median of target tightening torque (TS) The target tightening torque (TS) is determined.

(4) The axial force value (FS) with tolerance is obtained from the target tightening torque (TS) with tolerance.
Next, considering the above-mentioned target tightening torque (TS) with ± tolerance, the tapping screw has already been subjected to a predetermined torque before screw fastening, which can be called the seating point torque. Based on the seating point torque (TTP), the individual torque coefficient (uk) is obtained, and the axial force (FS) corresponding to the torque range of the target tightening torque (TS) is also obtained with ± tolerance. .

That is, the method for determining the tightening axial force of the tapping screw and the display device thereof according to the first embodiment calculates the axial force (FS) related to the tapping screw, and the tightening torque (TS) of the tapping screw is described above. Thus, a new finding that the tightening torque (TS) is applied before the seating point torque value (TTP) is the relationship between the conventionally known axial force (F) and screw tightening torque (T). The axial force (FS) with tolerance is calculated from FS = (TS−TTP) / uk based on (T−TTP) value obtained by subtracting the seating point torque (TTP) value from the equation (T = uk × dF). Ask.
Here, TS is the screw tightening torque, uk is the demonstration individual torque coefficient, FS is the axial force (kN), TPP is the seating point torque value, and the demonstration individual torque coefficient (uk) is the tapping. Torque coefficient when measured under the same conditions as the actual tightening conditions of the screw.

(5) Measurement example For example, when the screw is tightened, the rotational drive motor 2 has a rotational speed of 400 rotations / minute, an outer diameter of 2.9 mm (nominal diameter of 3 mm), a head outer diameter of 6.7 mm, and a neck length of 11 As an example of using a tapping screw with a specification of .44 mm, pitch 1.14, and trivalent chromate plating, the upper part has a 4.0 mm hollow hole on a 1.0 mm thick SPCC iron plate as a material to be fastened. The fastening shaft of the tapping screw according to the first embodiment is used for fastening the fastening member 9 and the lower fastening member 11 having a through hole of 2.6 mm to the ABS resin material having a thickness of 6.0 mm. When the force determination method and its display device are measured, the seating point torque value (TTP) with respect to the target tightening torque (TS), the demonstration individual torque coefficient (uk), the axial force with respect to the target tightening torque (FS) (F) Respectively Serial to become.

(a) Target tightening torque with tolerance (TS) = 0.53 ± 0.31 N · m
(b) Seating point torque (TTP) = 0.14 N · m
(c) Demonstration individual torque coefficient (uk) = 0.648
(d) Axial force with tolerance (FS) = 0.60 ± 0.47kN

(6) Numerical Expression Display Therefore, in the method for determining the tightening axial force of the tapping screw and the display device thereof according to the first embodiment, the obtained target tightening torque (TS) with tolerance and the axial force with tolerance ( For FS), the median value is indicated by a mathematical expression with the respective tolerances.

  4 is a graph on the monitor screen of the computer 7 as “torque value (N · m)” from the rotational torque sensor 4 and “axial force value (kN)” from the washer-type pressure sensor 10 shown in FIG. It is a figure which shows the outline which displays the said target tightening torque (TS) with a tolerance, and the said axial force (FS) with a tolerance over the figure which shows the display outline displayed, In FIG. 4, in the upper left of FIG. Displayed with “TS =” is the target tightening torque (TS) display with tolerance, and “FS =” is displayed next to the target tightening torque (TS) with tolerance at the upper left of FIG. What is done is the axial force (FS) display with tolerance, and the other symbols are the same as those shown in FIG.

  Furthermore, in the method for determining the tightening axial force of the tapping screw and the display device thereof according to the first embodiment, the target tightening torque (TS) determined as described above is used for the target tightening torque value (TS) with tolerance. The tolerance range is displayed on the graph together with the center value of TS). That is, in the method for determining the tightening axial force of the tapping screw according to the first embodiment and the display device thereof, the target tightening torque with tolerance (TS) central value (0.53) and the tolerance ( ± 0.31) is obtained and displayed together with the center value with tolerance, and the target tightening torque with tolerance (TS) = 0.53 ± 0.31 is displayed.

Then, the target tightening torque (TS) with tolerance is displayed in a graph.
The hatched display portion (0.22 (0.53-0.31) to 0.84 (0.53 + 0.31)) in FIG. 4 indicates the tolerance range of the target tightening torque (TS) in the above example. It is displayed. The lower limit is 0.22 (0.53-0.31), the upper limit is 0.84 (0.53 + 0.31), and the target tightening torque (TS) is within this range. With the tightening torque (TS) of the above, in the tapping screw of the above example, it is possible to avoid a seating defect in which the tightening torque is insufficient and a screw flap where the torque is excessively applied.

(7) Determination of torque range / axial force range and graph display Next, with respect to the torque value data from the rotational torque sensor 3 and the axial force value data from the washer-type pressure sensor 10 shown in FIG. Data (N · m) is displayed on the horizontal axis and the axial force value data (kN) is displayed on the vertical axis.

  FIG. 5 is the same as FIG. 3 and FIG. 4, and uses the method for determining the fastening axial force of the tapping screw according to the first embodiment and its display device, and the rotational speed 400 of the rotary drive motor 2 during screw fastening is shown. Rotation / min, When using a tapping screw with an outer diameter of 2.9 mm (nominal diameter of 3 mm), a head outer diameter of 6.7 mm, a neck length of 11.44 mm, a pitch of 1.14, and trivalent chromate plating As for the torque value data from the torque sensor 3 and the axial force value data from the washer-type pressure sensor 10, the torque value data (N · m) is plotted on the horizontal axis and the axial force value data (kN) is plotted on the horizontal axis. FIG. 5 is a diagram showing an outline displayed on the vertical axis, in FIG. 5, the “thin line display” graph indicates the “torque value (N · m)”, and the “thick line display” graph indicates the “axial force value (kN)”. ”,“ TS ”are the target tightening torque, and“ FS ”is The axial force, and the remaining “TF (female thread breaking torque)” and “TP (sitting point)” are the same as those shown in FIG. Further, the numbers indicated by “TS =” and “FS =” shown in the upper left of FIG. 5 are the target tightening torque with tolerance and the axial force (FS) with tolerance, which are obtained in the above (3). For the target tightening torque value (TS) with tolerance, the median value is displayed with tolerance.

  Further, in FIG. 5, the hatched portion is a graph display of the target tightening torque (TS) with tolerance shown by the hatching in FIG. 4. As described above, the hatching portion is the tightening torque (TS) within this range. For example, in the case of the tapping screw of the above example, it is possible to avoid a poor seating due to insufficient tightening torque and an excessively applied screw flapping.

  Next, the tolerance range of the center value is also displayed for the axial force with tolerance (FS). That is, the rotational speed of the rotary drive motor 2 at the time of screw tightening is 400 rotations / minute, the outer diameter is 2.9 mm (nominal diameter is 3 mm), the head outer diameter is 6.7 mm, the neck length is 11.44 mm, and the pitch is 1. .14 For tolerance of axial force (FS) = 0.60 ± 0.47 kN when using tapping screws with trivalent chromate plating specifications, tolerance (= ± 0.47) with center value (= 0.60) ) Is displayed overlapping the display of FIG.

  FIG. 6 shows a method for determining the fastening axial force of a tapping screw according to the first embodiment and its display device, wherein the rotational drive motor 2 has a rotational speed of 400 revolutions / minute and an outer diameter of 2.9 mm during screw fastening. (Nominal diameter 3 mm), head outer diameter 6.7 mm, neck length 11.44 mm, pitch 1.14, torque from the torque sensor 3 in the case of using a trivalent chromate plating specification Value data and axial force value data from the washer-type pressure sensor 10, the torque value data (N · m) is on the horizontal axis, the axial force value data (kN) is on the vertical axis, and the tolerance target It is a so-called torque / axial force diagram in which the range of the axial force with tolerance (FS) is superimposed on the schematic diagram showing the tightening torque (TS) by touching and displayed in a cross shape.

  In the hatched portion in FIG. 6, the axial force (FS) corresponding to the torque range of the target tightening torque (TS) derived in the above example is displayed with ± tolerance as with the target tightening torque (TS) with tolerance. By displaying in this way, the portion surrounded by a so-called square frame where the range of the target tightening torque with tolerance (TS) and the axial force with tolerance (FS) overlap is constant. It is possible to determine both the optimum torque and axial force determined from the material of the material to be fastened and the shape of the pilot hole at the same time for the tapping screw having the specifications of, and confirm it instantly visually. Means you can.

  By the way, in the method for determining the fastening axial force of the tapping screw according to the first embodiment and the display device thereof according to the first embodiment described above, in order to obtain the axial force with tolerance (FS), as described above, the second embodiment is used. The new knowledge that the torque (TTP) is applied to the axial force (FS) of the tapping screw also before the seating point in the method for determining the fastening axial force of the tapping screw and the display device has been known. This is applied to (T = uk × dF), which is a relational expression between the axial force (FS) and the screw tightening torque (T), and the (TS−TTP) value obtained by subtracting the seating point torque value (TTP) is used as a reference. FS = (TS−TTP) / uk is used to determine the axial force (FS) with tolerance (where TS is the tightening torque of the screw, uk is the demonstrative individual torque coefficient, FS is the axial force (kN), TPP) Is the seating point torque value. The click coefficients (uk), refers to the torque coefficient when measured in actual conditions the same conditions tightening tapping screws.) (See original document paragraph Nos. 0046).

  That is, the demonstrative individual torque coefficient (uk) obtained here is calculated from the following calculation formula by regarding the torque-axial force diagram as a primary curve. This will be described based on the display of FIGS. 5 and 6. As shown in FIGS. 5 and 6, the demonstration individual torque coefficient (uk) is “TP”, that is, the seating point (the head of the tapping screw). The slope of the straight line connecting the bottom surface (the point where the bottom surface has reached the top surface of the material to be fastened) and “TF”, that is, the internal thread breaking torque (torque that causes the tapping screw to cause the internal thread breaking), is regarded as the demonstration individual torque coefficient (uk). T Based on this assumption, calculation and display were performed.

  However, as shown in FIGS. 5 and 6, the torque-axial force line (shown in bold lines in FIGS. 5 and 6) is not necessarily a straight line, and slightly increases upward as it approaches the internal thread breaking torque (TF) of the tapping screw. It has a bow-like curve. For this reason, it has been found that the ± tolerance of the axial force (FS) is also inaccurate, and there is a problem that the verification individual torque coefficient (uk) is not correct.

  That is, as shown in FIGS. 5 and 6, “TP”, that is, a seating point (a point where the bottom surface of the head of the tapping screw reaches the upper surface of the material to be fastened) and “TF”, that is, a female screw breaking torque ( The inclination of the straight line connecting the torque that causes the tapping screw to break the female screw was slightly different from the demonstrative individual torque coefficient (uk) required for the tapping screw, and lacked accuracy.

  Therefore, while various studies are made to solve this problem, the minimum value (TSmin) of the target tightening torque (TS) and the target tightening torque (TS) for the torque-axial force line shown in FIGS. The torque-axial force curve (shown by a solid bold line in FIGS. 5 and 6) changes substantially linearly between the maximum values (TSmax), and the slope of the torque-axial force curve (uk) )

  Therefore, as a second embodiment, in the method for determining the tightening axial force of the tapping screw according to the first embodiment and the display device thereof according to the first embodiment, the torque-axial force curves shown in FIGS. 5 and 6 are substantially linear. For a certain part (between the minimum value (TSmin) of the target tightening torque (TS) and the maximum value (TSmax) of the target tightening torque (TS)), the axial force minimum value (FSmin) and the axial force maximum value ( The proof individual torque coefficient (uk) was determined from FSmax).

As already described in detail, the maximum value (TSmax) of the target tightening torque (TS) and the minimum value (TSmin) of the target tightening torque (TS) have been obtained as follows.
Target tightening torque (TS) maximum value (TSmax) = TF average value−4 × TF standard deviation Target tightening torque (TS) minimum value (TSmin) = TD average value + 4 × TD standard deviation here Thus, as described above, TF and TD are the internal thread breaking torque (TF: torque value that causes the tapping screw to cause the internal thread breaking) and the screwing torque (TD: the bottom face of the tapping screw head reaches the upper surface of the material to be fastened. The average value is the arithmetic average value of multiple data acquisitions (in some cases, the geometric mean value), and the standard deviation is the measured data with variations and its It is the square of the variance value obtained by dividing the sum of the squares of the difference from the average value by the number of data. The reason for subtracting or adding four times the standard deviation is to consider the safety of the required numerical value for the three times required in the statistical method, as described above.

  As described above, each standard deviation must be determined in consideration of each numerical value with this variation. To obtain the standard deviation, the median value of the deviations must be determined and fixed. The median of a certain value in the range is half (1/2) of the sum of the maximum value and the minimum value, and the median value of the female screw breaking torque (TF) having a variation range is the female screw breaking torque that is the maximum value. The screw screw torque (TD) having a variation range can be obtained by half (1/2) of the sum of the female screw break torque maximum value (TFmax) of (TF) and the minimum value of female screw break torque (TFmin) which is the minimum value. The median value was determined by half (1/2) of the sum of the maximum screw torque (TDmax), which is the maximum value, and the minimum screw torque minimum value (TDmin), which is the minimum value.

Median female screw breaking torque (TFmed) = (Maximum female screw breaking torque (TFmax) + Minimum female screw breaking torque (TFmin)) / 2
・ Screw torque median value (TDmed) = (Maximum screw torque (TDmax) + Minimum screw torque (TDmin)) / 2

  Here, the female screw breaking torque maximum value (TFmax) and the female screw breaking torque minimum value (TFmin), which are the minimum values, are the maximum value and the minimum value of any of a plurality of measured values, and the screwing torque. Similarly, the maximum value (TDmax) and the minimum screwing torque value (TDmin) are also the maximum value and the minimum value among the measurement values obtained a plurality of times. Then, a difference between these median values and the average values of the respective data is obtained, and the difference is used as the respective standard deviations. (1) TF average value = arithmetic average value of each data of TF (or synergistic value) (Average value), (2) standard deviation of TF = average value of TF−median value of TF, (3) average value of TD = arithmetic average value (or geometric average value) of each data of TD, (4) TD Standard deviation of TD = average value of TD−median value of TD is obtained, and further, the above TSmax and TSmin are obtained from the average value of TF, the standard deviation of TF, the average value of TD, and the standard deviation of TD, and TSmax = TF average value-4 x TF standard deviation, TSmin = TD average value + 4 x TD standard deviation, ± axial tolerance with tolerance (FS) and proof individual torque coefficient (uk) In addition to displaying, mathematical expressions have been displayed.

However, as described above, in the method for determining the tightening axial force of the tapping screw and the display device thereof according to the second embodiment, the target tightening torque maximum value (TSmax), the target tightening torque (TSmin), Since the axial force maximum value (FSmax) at TSmax (ms) and the axial force minimum value (FSmin) at TSmin (ms) can be directly obtained from a plurality of acquisition data, TSmax, TSmin, FSmax, From FSmin, the verification individual torque coefficient (uk) is obtained directly from the following expression from the relational expression uk = TS / FS of torque coefficient (uk), tightening torque (TS) and axial force (FS). It is.
uk = (TSmax−TSmin) / (FSmax−FSmin)
Here, TSmax is the maximum value of the target tightening torque (TS), TSmin is the minimum value of the target tightening torque (TS), FSmax is the maximum axial force value at the time of TSmax (ms), and FSmin. Is the minimum axial force at the time of TSmin (ms) and can be directly obtained from a plurality of measurement data.

  Based on the verification individual torque coefficient (uk) obtained in this way, in the method for determining the tightening axial force of the tapping screw according to the second embodiment and its display device, the median value of the target tightening torque (TS) and It was calculated with ± tolerance along with the median of axial force, and further, it was displayed numerically with ± tolerance.

This will be described with reference to the drawings.
FIG. 9 shows how to determine the axial force value (kN) on the horizontal axis and the axial force value data (kN) on the horizontal axis using the method for determining the fastening axial force of the tapping screw according to the second embodiment and its display device. FIG. 5 is a torque / axial force diagram displayed as an axis, and is a diagram corresponding to FIGS. 5 and 6. FIG. 5 and FIG. 6 are different from FIGS. 5 and 6 in FIG. 5 and FIG. uk), but in the same torque and axial force diagram, a straight line part (that is, a new line between the target tightening torque minimum value and the target tightening torque maximum value is found to be linear) The target tightening torque minimum value (TSmin), the target tightening torque maximum value (TSmax), and the axial force minimum value (FSmin) at the time of TSmin (ms) and the shaft at the time of TSmax (ms). From the maximum force value (FSmax) to the target tightening torque range and shaft Determined range, and setting equation the target tightening torque and axial force with ± tolerances with which the hatched.

5 and FIG. 6 are basically the same as FIG. 5 and FIG. 6, although there are differences in FIG. 5 and FIG.
As shown in FIG. 9, the demonstration individual torque coefficient (uk) includes the target tightening torque minimum value (TSmin), the target tightening torque maximum value (TSmax) and the minimum axial force at the time of TSmin (ms) based on actually measured data. An appropriate target tightening torque range (TS) and its torque range based on an accurate demonstration individual torque coefficient (uk) that can be directly obtained from the value (FSmin) and the maximum axial force value (FSmax) at the time of TSmax (ms) The axial force (FS) range corresponding to is indicated by hatching, so the overlapping area, the so-called quadrangular framed portion, is the material of the material to be fastened used for the tapping screw having a certain specification. It is possible to simultaneously determine both the optimum torque and axial force determined from the shape of the pilot hole and the shape of the prepared hole, and to visually confirm it.
Further, since the target tightening torque (TS) and the axial force (FS) range can be numerically displayed with ± tolerance, accurate display based on the correct demonstration individual torque coefficient (uk) can be achieved.

  The present invention is used for analyzing the tightening axial force of a tapping screw.

DESCRIPTION OF SYMBOLS 1 Torque analyzer 2 Rotation drive motor 3 Rotation torque sensor 4 Handle 5 Bit holder 6 Screw bit 7 Computer 8 Tapping screw 9 Fastening member 10 Washer type pressure sensor 11 Fastened member 12 Support jig 101 Axial force measurement sensor 102 Cylindrical member 102a Protrusion part 103 (Upper) Flange 104 (Lower) Flange 105 Presser 106 Load Sensor 107 Lead Wire 111 Female Thread Member 111a Female Thread Hole 112 Male Thread Member 112a Shaft 112b Head 201 Bolt Axial Force Measuring Machine 202 Tightening Bolt 221 Bolt Head Part 222 Tightening nut 203 Center hole type load cell 204 Latchet wrench, etc. 241 Latchet wrench head 205 Torque wrench or gyro wrench 251 Torque wrench or gyro wrench replacement head 252 Socket 206 Sensor interface 261, 262 Connection terminal 207 Load gauge core 273 Through hole 281, 282, 283 Strain gauge 208a, 208b, 208c, 208d Gauge lead 209 Protective case 215 PC A, B Fastened body TD Screwed Torque (Torque required for the bottom surface of the tapping screw to reach the top surface of the material to be fastened)
TF Internal thread breaking torque (Torpin screw causing internal thread breaking)
TP seating point (point where the bottom of the head of the tapping screw reaches the top surface of the material to be fastened)
FF Tightening fracture axial force TS Target tightening torque μ Friction coefficient μn Bearing surface friction coefficient

In order to solve the above-mentioned problems, the invention according to claim 1 of the present application is a method for determining a target tightening torque of a tapping screw and / or a tightening axial force of a tapping screw, wherein at least a screw bit, a rotational torque sensor, and a computer are provided. A pressure sensor is placed between the fastening member to be fastened with the tapping screw to be measured and the fastening member, and the tapping screw engaged with the screw bit is inserted from above the fastening member. The target tightening torque of the tapping screw and / or the tightening axial force of the tapping screw is determined based on the data from the rotational torque sensor and the data from the pressure sensor from the start of tightening until the female screw breaks. Features.
The invention according to claim 2 of the present application is the method for determining the target tightening torque of the tapping screw and / or the tightening axial force of the tapping screw according to claim 1, wherein the pressure sensor is the tapping screw to be measured. It is a washer-type pressure sensor having a hole through which is inserted.
Further, the invention according to claim 3 of the present application is the method for determining the target tightening torque of the tapping screw and / or the tightening axial force of the tapping screw according to the first aspect of the invention, wherein the target tightening torque of the tapping screw is determined. Determine the tightening torque and screwing torque from the seating of the tapping screw to the female screw breakage and the female screw breaking torque by multiple measurements, and average values of the screwing torque and female screw breaking torque obtained by the multiple measurements. And the sum of the average value of the screwing torque obtained from the multiple times measurement and the standard deviation of four times the average value of the screwing torque is set as the minimum value of the target tightening torque, and the internal thread breakage obtained from the multiple times measurement The difference between the average value of the torque and the standard deviation of 4 times the average value of the female screw breaking torque is taken as the maximum value of the target tightening torque. The half of the sum of the minimum tightening torque values (1/2) is the median value of the target tightening torque of the tapping screw, and half the difference between the maximum value and the minimum value is the target tightening torque of the tapping screw. It is characterized by a tolerance of ± attached torque.
The invention according to claim 4 of the present invention is the method for determining the target tightening torque of the tapping screw and / or the tightening axial force of the tapping screw according to claim 3, wherein the target tightening of the tapping screw with ± tolerance is performed. Torque is displayed as a mathematical expression and / or a band-shaped range on the monitor screen of the computer.
The invention according to claim 5 of the present application is the method for determining the target tightening torque of the tapping screw and / or the tightening axial force of the tapping screw according to claim 3, wherein the axial force (FS) of the screw and the screw are determined. FS = (T−TTP) / uk (T is the tightening torque of the screw, uk is the demonstration individual torque coefficient, FS is the axial force (kN), and TPP is the relational expression of the tightening torque (T). On the basis of the seating point torque value), an axial force with ± tolerance is determined from the target tightening torque with ± tolerance.
Further, in the invention according to claim 6 of the present invention, in the method for determining the target tightening torque of the tapping screw and / or the tightening axial force of the tapping screw according to claim 5, the ± tensioning axial force of the tapping screw is Further, a tolerance display and / or a band-shaped range is displayed on the monitor screen of the computer.
Furthermore, the invention according to claim 7 of the present application is the method for determining the target tightening torque of the tapping screw and / or the tightening axial force of the tapping screw according to claim 6, wherein the torque value data from the rotational torque sensor is obtained. The horizontal axis indicates the axial force value data from the pressure sensor and the vertical axis indicates a band-shaped range on the monitor screen of the computer.
Further, the invention according to claim 8 of the present application is the method for determining the target tightening torque of the tapping screw and / or the tightening axial force of the tapping screw according to claim 7, wherein the mathematical expression is displayed on the monitor screen of the computer and / or Alternatively, the target tightening torque with ± tolerance of the tapping screw and the axial force with tolerance of the tapping screw displayed in a band-like range are displayed in a cross shape at the same time.
Next, an invention according to claim 9 of the present application is a display device for a target tightening torque of a tapping screw and / or a tightening axial force of a tapping screw, and a torque analyzer including at least a screw bit, a rotational torque sensor, and a computer, It consists of a pressure sensor arranged between the fastening member to be fastened with the measuring tapping screw and the material to be fastened. The tapping screw engaged with the screw bit is inserted from above the fastening member to start tightening. The data from the rotational torque sensor and the data from the pressure sensor until the female screw breaks are captured and displayed on the computer.
The invention according to claim 10 of the present application is the display device for the target tightening torque of the tapping screw and / or the tightening axial force of the tapping screw. The target tightening torque of the screw and / or the tightening axial force of the tapping screw is displayed.
The invention according to claim 11 of the present application is the method of determining the target tightening torque of the tapping screw and / or the tightening axial force of the tapping screw according to claim 1, wherein the target tightening torque of the tapping screw is determined. Is determined by multiple measurements of the tightening torque, screwing torque and female screw breaking torque from the seating of the tapping screw to the female screw breaking, and the maximum and minimum values of the tightening torque up to the obtained female screw breaking torque. The tightening torque range and the corresponding axial force range based on the demonstrative individual torque coefficient obtained from the following formula from the maximum axial force value at the maximum tightening torque value and the minimum axial force value at the minimum tightening torque value: Is a tolerance of the target tightening torque of the tapping screw.
uk = (TSmax−TSmin) / (FSmax−FSmin) (uk is the demonstration individual torque coefficient, TSmax is the maximum value of the target tightening torque (TS), TSmin is the minimum value of the target tightening torque (TS), FSmax Is the maximum axial force at TSmax (ms), FSmin is the minimum axial force at TSmin (ms))
The invention according to claim 12 of the present application is the method for determining the target tightening torque of the tapping screw and / or the tightening axial force of the tapping screw according to claim 11, wherein the tightening torque range is the target of the tapping screw. It is determined as a tolerance of the tightening torque, and a mathematical expression and / or a band-shaped range is displayed on the monitor screen of the computer.
The invention according to claim 13 of the present application is the method for determining the target tightening torque of the tapping screw and / or the tightening axial force of the tapping screw according to claim 11, wherein the torque value data from the rotational torque sensor is obtained. The axial force value data from the pressure sensor is plotted on the horizontal axis, and the axial force with a tolerance of the tapping screw is displayed in a band-shaped range on the monitor screen of the computer.
Furthermore, the invention according to claim 14 of the present invention is the method for determining the target tightening torque of the tapping screw and / or the tightening axial force of the tapping screw according to claim 13, wherein the mathematical expression is displayed on the monitor screen of the computer and / or Alternatively, the target tightening torque with ± tolerance of the tapping screw and the axial force with tolerance of the tapping screw displayed in a band-like range are displayed in a cross shape at the same time.
The invention according to claim 15 of the present application displays the target tightening torque of the tapping screw and / or the tightening axial force of the tapping screw by the determination method according to any of claims 11 to 14. A display device for the target tightening torque of the tapping screw and / or the tightening axial force of the tapping screw.

Claims (15)

  A tapping screw in which a pressure sensor is arranged between a fastening member arranged at the top and bottom to be fastened with a tapping screw to be measured and a to-be-fastened member in a torque analyzer having at least a screw bit and a rotational torque sensor and engaged with the screw bit Is inserted from above the fastening member to start tightening, and based on the data from the rotational torque sensor and the data from the pressure sensor until the female screw is broken, the target tightening torque of the tapping screw and / or the tightening of the tapping screw is performed. A method for determining a target tightening torque for a tapping screw and / or a tightening axial force for a tapping screw, wherein the axial force is determined.   The target pressure of the tapping screw and / or the tapping shaft of the tapping screw according to claim 1, wherein the pressure sensor is a washer type pressure sensor having a hole through which the measured tapping screw is inserted. How to determine power.   The determination of the target tightening torque of the tapping screw is to determine the tightening torque and screwing torque from the seating of the tapping screw to the destruction of the female screw and the female screw breaking torque by a plurality of measurements, and the screwing obtained by the plurality of measurements. Each average value of the torque and internal thread breaking torque is obtained, and the sum of the average value of the screwing torque obtained from the plurality of measurements and the standard deviation four times the screwing torque average value is set as the minimum value of the target tightening torque, and The difference between the average value of the female screw breaking torque obtained from the multiple measurements and the standard deviation of four times the average value of the female screw breaking torque is taken as the maximum value of the target tightening torque, and the target tightening torque maximum value and the target tightening torque Half the sum of the minimum values (1/2) is the median value of the target tightening torque of the tapping screw, and half the difference between the maximum value and the minimum value is the tapping screw. The biasing target tightening torque for tapping screw according to claim 1 and / or tapping method for determining the fastening shaft force of the screw, characterized in that the ± tolerance of the target tightening torque pin thread.   The target tightening torque of the tapping screw according to claim 3, wherein the target tightening torque with ± tolerance of the tapping screw is displayed on the monitor screen of the computer as a mathematical expression and / or a band-shaped range. Or a method for determining the tightening axial force of the tapping screw.   FS = (T−TTP) / uk (T is the screw tightening torque, uk is the demonstration individual torque coefficient, and FS is the relational expression between the axial force (FS) and the screw tightening torque (T) for the screw. The axial force with tolerance (± N) is determined based on the target tightening torque with tolerance (±) based on the axial force (kN) and TPP is a seating point torque value). A method for determining a target tightening torque and / or a fastening axial force of a tapping screw.   6. The target tightening torque of the tapping screw and / or the tapping pin according to claim 5, wherein the axial force with a tolerance of the tapping screw is displayed on a monitor screen of the computer with a tolerance display and / or a band-shaped range. Determination method of screw tightening axial force.   7. The belt-shaped range is displayed on the monitor screen of the computer, with the torque value data from the rotational torque sensor on the horizontal axis and the axial force value data from the pressure sensor on the vertical axis. The method for determining the target tightening torque of the tapping screw and / or the tightening axial force of the tapping screw.   The target tightening torque with ± tolerance of the tapping screw and the axial force with ± tolerance of the tapping screw displayed on the monitor screen of the computer and / or in a band-like range are simultaneously displayed in a cross shape. The method for determining the target tightening torque of the tapping screw and / or the tightening axial force of the tapping screw according to claim 7.   A tapping screw comprising at least a screw bit, a torque analyzer including a rotational torque sensor and a computer, and a pressure sensor disposed between a fastening member to be fastened by a tapping screw to be measured and a fastened material, and being engaged with the screw bit. A tapping screw for inserting and displaying data from the rotational torque sensor and data from the pressure sensor from the time when the fastening member is inserted and started to be tightened until the female screw of the fastened member is broken. Display device for target tightening torque and / or tightening axial force of tapping screw.   The target tightening torque of the tapping screw and / or the target tightening torque of the tapping screw and / or the tightening axial force of the tapping screw are displayed by the determination method according to any one of claims 1 to 8. Or a display device of the tightening axial force of the tapping screw. The target tightening torque of the tapping screw is determined by measuring the tightening torque and screwing torque from the seating of the tapping screw until the female screw breakage and the female screw breaking torque by a plurality of measurements. Based on the maximum and minimum values of the tightening torque, the maximum axial force at the maximum tightening torque value, and the minimum axial force at the minimum tightening torque value, the tightening is based on the demonstrative individual torque coefficient obtained by the following equation. 2. The target tightening torque for the tapping screw and / or the tightening of the tapping screw according to claim 1, wherein the attaching torque range and the corresponding axial force range are defined as ± tolerances of the target tightening torque of the tapping screw. A method for determining the axial force.
uk = (TSmax−TSmin) / (FSmax−FSmin) (uk is the demonstration individual torque coefficient, TSmax is the maximum value of the target tightening torque (TS), TSmin is the minimum value of the target tightening torque (TS), FSmax Is the maximum axial force at TSmax (ms), FSmin is the minimum axial force at TSmin (ms))   In the method for determining the target tightening torque of the tapping screw and / or the tightening axial force of the tapping screw according to claim 11, the tightening torque range is determined as ± tolerance of the target tightening torque of the tapping screw, 12. The method for determining a target tightening torque of a tapping screw and / or a tightening axial force of a tapping screw according to claim 11, wherein a mathematical expression and / or a band-shaped range are displayed on a monitor screen of a computer.   The torque value data from the rotational torque sensor is plotted on the horizontal axis and the axial force value data from the pressure sensor is plotted on the vertical axis, and the axial force with ± tolerance of the tapping screw is displayed in a band-like range on the computer monitor screen. The method for determining the target tightening torque of the tapping screw and / or the tightening axial force of the tapping screw according to claim 11.   The target tightening torque with ± tolerance of the tapping screw and the axial force with ± tolerance of the tapping screw displayed on the monitor screen of the computer and / or in a band-like range are simultaneously displayed in a cross shape. The method for determining the target tightening torque of the tapping screw and / or the tightening axial force of the tapping screw according to claim 13. The target tightening torque of the tapping screw and / or the target tightening torque of the tapping screw and / or the tightening axial force of the tapping screw is displayed by the determination method according to any one of claims 11 to 14. Or a display device of the tightening axial force of the tapping screw.

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