JP2005061979A - Threaded hole location measuring tool, and the threaded hole location measuring method using this - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a threaded hole position measuring tool capable of measuring accurately the position of a threaded hole, and easily mountable/dismountable when performing measurement, and a threaded hole position measuring method using the tool. <P>SOLUTION: This tool has a screw part formed on one side in the axial direction of a shaft-shaped body, to be fixed in the threaded hole to be measured having a counterbore formed on the inlet side, and a screw head part formed on the other side of the shaft-shaped body, wherein the circumference includes a cylindrical shape used for measuring the threaded hole position, and a tapered part formed between the screw part and the screw head part so as to spread from the screw part side toward the screw head part side. The taper angle has a larger shape than the angle of the tapered part formed by the counterbore, and when fixing the screw part into the threaded hole to be measured, the tapered part of the screw head part abuts on the counterbore abutting on a part of the tapered part of the counterbore. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a screw hole position measuring jig for measuring the position of a screw hole of a workpiece, and a screw hole position measuring method using the same.

  For example, a gas turbine case of an automobile engine is divided into two cases by aluminum die-casting, and one is provided with a bolt through hole and the other is provided with a screw hole. However, since there are many positions to be fixed with bolts, there are cases where the assembly is not possible when there is a positional deviation in the screw holes. Therefore, it is necessary to measure the position of the screw hole, sort out the non-defective product and the defective product, and remove the defective product.

  However, a caliper or a three-dimensional measuring device is generally provided as a measurement facility, but it is difficult to directly measure the position of the screw hole with a caliper or a three-dimensional measuring device. For example, in the measurement using a caliper, a so-called “beak” portion that is brought into contact with the inner surface at the time of measurement may not be able to be measured because it does not enter the screw hole, and in the measurement using a three-dimensional measuring instrument, the probe contact position ( This is because an erroneous measurement may occur depending on the top and the slope.

  Therefore, the position of the screw hole is measured using a caliper or a three-dimensional measuring device via a screw gauge for inspecting the screw portion. For example, the position of the screw hole is obtained by measuring the shaft portion of the screw gauge with a caliper or a three-dimensional measuring instrument with the screw gauge attached.

  In addition, as a device that facilitates measurement, there is a measurement device that uses the principle of an air micrometer to enable non-contact measurement of screw holes (for example, see Patent Document 1).

JP-A-6-323835 (paragraphs [0011]-[0045], FIGS. 1 to 25)

  By the way, the screw gauge is intended for the inspection of the screw, and since the thread portion is made with high accuracy, the cost is high, and it is usually performed to prepare dozens of gauges with a certain nominal diameter. Absent. Therefore, when measuring the positions of many screw holes using a screw gauge, the screw gauge is frequently attached and detached. Moreover, since the thread part of a screw gauge is highly accurate, when the backlash with a screw hole is small, the attachment or detachment is not easy. Moreover, since the accuracy of the shaft portion of the screw gauge is not normally required, the measurement result includes an error. Furthermore, it includes errors due to tilting of the screw holes and backlash with the screw holes.

  In addition, since measurement with a three-dimensional measuring instrument is automatically performed according to a program, it is necessary to attach a screw gauge so that the position of the shaft portion is constant. Since it does not have a directional positioning function, it is troublesome for the operator to attach the shaft portion so that the position of the shaft portion is constant.

  On the other hand, it is often difficult to provide a measuring device for the purpose of measuring only screw holes as disclosed in Patent Document 1 in terms of economy and space.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to measure the position of a screw hole that can accurately measure the position of a screw hole and is easily attached and detached at the time of measurement. It is to provide a jig and a screw hole position measuring method using the jig.

  In order to solve the above-mentioned problem, the invention according to claim 1 is a screw formed on one side of the shaft-like body in the axial direction and fixed to a measurement screw hole having a counterbore formed on the entrance side. And a screw head including a cylindrical shape whose outer periphery is used for measuring the screw hole position, and between the screw part and the screw head, from the screw part side. When the taper portion is formed so as to expand toward the screw head side, and the taper angle is larger than the angle of the taper portion formed by the counterbore, and when the screw portion is fixed to the screw hole to be measured Further, the taper portion of the screw head is in contact with a part of the taper portion of the counterbore.

  The invention according to claim 2 is characterized in that the taper portion of the screw head is set so that the taper angle is 130 ° ± 1 °.

  According to a third aspect of the present invention, as a screw hole position measuring jig, a screw portion is formed on one side, and a screw head including a columnar shape is formed on the other side, between the screw portion and the screw head. In addition, a taper portion is formed so as to widen from the screw portion side toward the screw head side, and the taper angle is larger than the angle of the taper portion formed by the counterbore formed at the entrance of the screw hole to be measured. Preparing the one made in step, fixing the screw hole position measuring jig to the screw hole, and contacting the taper portion of the screw head with a part of the tapered portion of the counterbore, Measuring the position of the axial center of the screw hole position measuring jig from the cylindrical outer periphery of the screw head, and setting the position of the axial center as the position of the screw hole to be measured. Yes.

  The invention according to claim 4 is characterized in that the preparing step prepares a plurality of screw hole position measuring jigs corresponding to screw holes of various nominal diameters.

  The invention according to claim 5 is characterized in that the length of the cylindrical portion of the prepared screw hole position measuring jig is made equal.

  The invention according to claim 6 is characterized in that the taper portion of the screw head is set so that an angle of the taper is 130 ° ± 1 °.

  According to the screw hole position measuring jig according to claim 1, since the taper portion comes into contact with a part of the tapered portion of the counterbore when fixed to the screw hole to be measured, there is no backlash, And the position of a screw hole can be measured.

  According to the screw hole position measuring jig according to the second aspect of the present invention, it is possible to attach the screw hole while avoiding flashing of the screw hole, so that no erroneous measurement due to a fall occurs.

  According to the screw hole position measuring method according to claim 3, since the taper portion that comes into contact with a part of the tapered portion of the counterbore when fixed to the screw hole to be measured is provided, there is no backlash, and The position of the screw hole can be measured.

  According to the screw hole position measuring method according to the fourth aspect of the present invention, it is convenient to prepare screw hole position measuring jigs for various screw holes.

  According to the screw hole position measuring method according to claim 5, since the height of the cylindrical shape of the screw head can be made equal, for example, when measuring automatically according to a program with a three-dimensional measuring instrument, There is no need to change the height to be measured depending on the nominal diameter.

  According to the screw hole position measuring method according to the sixth aspect, since the screw hole can be mounted while avoiding the flash hole, erroneous measurement due to falling does not occur.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of a screw hole position measuring jig and a screw hole position measuring method using the same according to the present invention will be described in detail with reference to the drawings.

(One embodiment of a jig for measuring screw hole position)
FIG. 1 shows an embodiment of the present invention, and shows a structure of a screw hole position measuring jig 1 fixed to a screw hole of a workpiece to be measured. FIG. FIG. 1 and FIG. 1B are front views. This screw hole position measuring jig 1 has a shaft-like body. As shown in FIG. 1, a screw portion 11 in which a screw having a predetermined nominal diameter is machined on the right side, and a caliper or a three-dimensional measuring instrument on the left side. Between the screw head 12 and the screw portion 11, there is a taper portion 13 whose diameter gradually increases from the screw portion 11 side toward the screw head 12 side. doing. Further, in FIG. 1, a bald portion 14 having a diameter smaller than the diameter of the valley of the screw is provided between the left end of the screw portion 11 and the tapered portion 13, but the bald portion 14 is easy to process the screw. It is not necessary to do.

  In addition, the end face of the screw head 12 is provided with a slot, but this is for inserting and turning a minus screw driver during installation, and a plus screw driver can be inserted into a cross groove shape. In addition, when the diameter of the screw head 12 is sufficient for the operator to rotate and tighten by hand, there is no need for a slit or a cross groove shape. Further, the end portion is chamfered in consideration of safety in handling.

  If the screw portion 11 has a length that can include at least the number of screw threads that do not bite the screw hole of the workpiece when the hole position measuring jig 1 is tightened to the screw hole with a predetermined torque. Good. In addition, preferably, if the accuracy of the thread is made to be about the second grade of the thread grade defined by JIS (Japan Industrial Standard), the screw hole has a backlash, so that it can be attached to and detached from the workpiece. It can be done smoothly.

The minimum diameter of the taper portion 13 on the screw portion 11 side is not more than the outer diameter of the screw of the screw portion 11 and not less than a diameter having sufficient strength against bending force, shearing force, etc., for example, as shown in FIG. when having Nanige portion 14, the minimum diameter of the diameter of the relief portion 14, if no relief portion 14, the outer diameter D ₁ of the screw and the minimum diameter, thread taper portion 13 The maximum diameter W ₁ on the head 12 side is made larger than the nominal diameter of the screw (the nominal diameter of the screw hole or the screw portion 11 is the same in either case) (for example, 2 mm larger in diameter), and the taper angle T Is larger than the taper angle Z of the tapered portion of the counterbore of the screw hole described later, and is preferably 130 ° ± 1 °. Although will be described later action of the tapered portion 13, it reveals thereby and the reason for increasing the maximum diameter W ₁ than the nominal diameter of the screw, the reason or the like for greater than 120 degrees taper angle T.

The length l ₁ of the cylindrical portion of the screw head 12 is sufficient to receive a so-called “jou” or “beak” portion of the caliper that is contacted for measurement in the axial direction, or a three-dimensional measurement. to receive a probe of the vessel may be there is sufficient length, also, with respect to the length l ₀ for example the whole of as a good balance when a worker picked the screw head 12 with a finger 1/3 The above length is preferable. In addition, the diameter W ₁ of the cylindrical portion of the screw head 12 may be a step shape smaller than the maximum diameter of the tapered portion 13, but it is easy to make, easy to pick, and for calipers and three-dimensional measuring instruments. From the ease of receiving the probe (easy to measure), as shown in FIG. 1, it is the same as the maximum diameter W ₁ of the tapered portion 13, that is, the nominal diameter of the screw (the nominal diameter of the screw hole or the screw portion 11). A larger diameter is preferred in either case.

  Further, such a screw hole position measuring jig 1 can be created by cutting with a lathe or a machining center, but in order to ensure the coaxiality of the screw portion 11, the taper portion 13, and the screw head 12, It is preferable that the machining of these parts is carried out simultaneously without changing the center axis when the center axis is set in the machining process. Further, the screw hole position measuring jig 1 can be formed not by cutting but by rolling or header processing.

(Screw hole position measurement method)
Next, the screw hole position measuring method using the above-described screw hole position measuring jig 1 will be described in detail. FIG. 2 is a flowchart showing an example of main steps of the screw hole position measuring method according to the present invention.

  First, a plurality of screw hole position measuring jigs 1 are prepared for various nominal diameters (step S101 in FIG. 2; hereinafter, abbreviated as S101; the same applies to others). For example, as shown in FIG. Nine types of screw hole position measuring jigs 1a to 1i from M6 to M24 are prepared and stored in the case 3 in advance. In this way, if a plurality of screw hole position measuring jigs corresponding to each of the various nominal diameter screw holes are prepared, it is possible to cope with various screw holes in the workpiece, When the screw hole is vacated, there is a case where it is not necessary to attach or detach the screw hole position measuring jig 1 during measurement, which is convenient.

  Then, a plurality of screw hole position measuring jigs 1 corresponding to the nominal diameter of the screw hole 21 vacated in the workpiece 2 to be measured are selected and fixed to the screw hole 21 of the workpiece 2 (S102). ). FIG. 4 shows a cross-sectional view of the screw hole position measuring jig 1 fixed to the screw hole 21. The screw hole 21 has a counterbore 22 having a taper portion 221. Usually, the taper angle Z of the taper portion 221 of the counterbore 22 is 90 degrees to 120 degrees (120 degrees in FIG. 4). On the other hand, the taper angle T of the taper portion 13 of the screw hole position measuring jig 1 is set to be larger than 120 degrees of the taper angle Z of the taper portion 221 of the counterbore 22 and not more than 180 degrees (130 degrees in FIG. 4). Therefore, as shown in FIG. 4, when the taper portion 13 abuts against the end portion of the counterbore 22 (a part of the counterbore taper portion 221), the screw hole position measuring jig 1 does not rattle and the screw hole position measurement is performed. The axial center of the jig 1 is fixed so as to coincide with the axial center of the counterbore 22. However, in the processing of the screw hole using a machining center or the like, the coaxiality between the screw hole and the counterbore is secured. Therefore, the axial center of the screw hole position measuring jig 1 is fixed so as to coincide with the axial center of the counterbore 22, that is, the axial center of the screw hole 21.

  Further, when a screw is machined into the screw hole, burr may be generated at the entrance of the screw hole, but the taper angle T of the taper portion 13 is larger than the taper angle Z of the taper portion 221 of the counterbore 22 (FIG. 4). Therefore, a gap is formed between the entrance of the screw hole and the taper portion 13, so that the burr and the taper portion 13 come into contact with each other and the screw hole position measuring jig 1 may be tilted and attached. No. In the case where the screw head 12 is tilted and attached, the screw hole position changes depending on the axial position of the screw head 12 to be measured. Therefore, the screw hole position can be accurately measured by making the taper angle T larger than 120 degrees to eliminate the tilt due to the contact with the flash. Further, the taper angle T is preferably set to 130 ° ± 1 °, and if it is 130 ° ± 1 °, the contact with the flash is more reliably avoided experimentally, and the taper is stably attached to the counterbore.

  Even if the counterbore diameter is larger than the diameter of the screw head 12, the screw hole position measuring jig 1 is not shown, but the end of the taper portion 13 abuts a part of the taper portion 221 of the counterbore 22, Since a gap is formed between the entrance of the screw hole and the taper portion 13, it can be attached so as to coincide with the axial center of the screw hole 21 without similarly falling down by the flash.

Further, the screw hole position measuring jig 1 is fixed in a state where the tapered portion 13 is in contact with a part of the tapered portion 221 of the counterbore 22 of the workpiece 2 as described above. When measuring automatically according to a program, the screw head 12 can be easily fixed at a constant height. Further, if the length l ₁ of the cylindrical portion of each screw head 12 of the screw hole position measuring jig corresponding to various nominal diameters shown in FIG. 3 is made equal, the measurement height depends on the nominal diameter. Therefore, it is more convenient if the height to be measured is set to the same setting when measuring automatically according to the program.

  Next, the position of the screw hole 21 is obtained by measuring the screw head 12 of the screw hole position measuring jig 1 attached to the screw hole 21 as the position of the screw hole 21 of the workpiece 2 (S103). For example, as shown in FIG. 5, measurement can be performed by bringing a probe of a three-dimensional measuring instrument into contact with the screw head 12, or using calipers as shown in FIG. By measuring the screw head 12 in this way, the axis of the screw hole position measuring jig 1 can be measured, and the axis of the screw hole position measuring jig 1 is aligned with the axis of the screw hole 21. Since they are fixed so as to match, the position of the screw hole 21 can be obtained.

It is a side view which shows the shape of the jig | tool for screw hole position measurement which concerns on this invention. It is a front view which shows the shape of the jig | tool for screw hole position measurement which concerns on this invention. It is a flowchart which shows an example of the process of the screw hole position measuring method using the jig for screw hole position measurement of this invention. It is an example of a plurality of screw hole position measuring jigs prepared for each of various nominal diameters. It is sectional drawing which shows a mode that the jig for screw hole position measurement was fixed to the screw hole. It is a figure which shows the mode of a measurement using the jig | tool for screw hole position measurement. It is a figure which shows the mode of a measurement using the jig | tool for screw hole position measurement.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Screw hole position measuring jig 11 Screw part 12 Screw head 13 Tapered part 14 Narrow part 2 Workpiece 21 Screw hole 22 Counterbore 221 Tapered part 3 Case

Claims (6)

A threaded portion that is formed on one side of the shaft-like body in the axial direction, and is fixed to a measurement target screw hole in which a counterbore is formed on the entrance side;
A screw head including a cylindrical shape formed on the other side of the shaft-like body and having an outer periphery used for measuring the screw hole position;
A taper portion is formed between the screw portion and the screw head so as to expand from the screw portion side toward the screw head side, and the taper angle is larger than the angle of the taper portion formed by the counterbore. A screw hole position measuring jig having a large shape, wherein when the screw portion is fixed to the screw hole to be measured, the taper portion of the screw head abuts a part of the taper portion of the counterbore. . The screw hole position measuring jig according to claim 1, wherein the taper portion of the screw head is set so that an angle of the taper is 130 degrees ± 1 degree. As a screw hole position measuring jig, a screw portion is formed on one side, and a screw head including a cylindrical shape is formed on the other side, and the screw head from the screw portion side is formed between the screw portion and the screw head. A taper portion is formed so as to expand toward the portion side, and the taper angle is prepared with a shape larger than the angle of the taper portion formed by the counterbore formed at the entrance of the screw hole to be measured; and
Fixing the screw hole position measuring jig to the screw hole, and contacting the taper portion of the screw head with a part of the tapered portion of the counterbore;
Measuring the position of the axis of the screw hole position measuring jig from the outer periphery of the cylindrical shape of the screw head, and setting the position of the axis as the position of the screw hole to be measured. Screw hole position measurement method. The screw hole position measuring method according to claim 3, wherein the preparing step prepares a plurality of screw hole position measuring jigs corresponding to screw holes of various nominal diameters. The screw hole position measuring method according to claim 4, wherein the cylindrical portion of the prepared screw hole position measuring jig has the same length. The screw hole position measuring method according to any one of claims 3 to 5, wherein the taper portion of the screw head is set so that an angle of the taper is 130 degrees ± 1 degree.

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