JP2729073B2 - Measuring device for female thread - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial applications]

The present invention relates to a female thread measuring device for measuring the taper, effective diameter, and standoff of a female thread in a special threaded joint used for, for example, an oil country tubular good.

[Prior art]

Conventionally, the measurement of female threads in special threaded joints used for oil country tubular goods has not been stipulated in the API standard, but the taper, effective diameter, stand-off, and the like have been measured in accordance with the API standard. The taper measurement of the female thread is usually performed by a dedicated female thread taper measuring gauge using a dial gauge or a female thread taper measuring caliper. It was measured by a plug gauge for measurement. The effective diameter is not included as a measurement item in the API standard, but is guaranteed by the stand-off.

[Problems to be solved by the invention]

The conventional method for measuring an internal thread has a problem that it takes a long time to measure since different gauges are used for the taper and the standoff. Also, when measuring the taper, an error will occur if the measurement is not performed reliably on the same diameter of the internal thread of the female thread. Was. Further, when measuring the standoff, there is a problem that the measurement result varies due to the tightening force of the plug gauge. The present invention has been made in view of the conventional problems described above, and uses the same gauge for the taper and standoff of the female thread, and can be easily performed without skill.
An object of the present invention is to provide a screw measuring device so that a measurement can be performed without any variation.

[Means for Solving the Problems]

The present invention relates to a male screw part which can be screwed into a part of a female screw to be measured, and the female screw part is formed when the male screw part is screwed with the female screw. A cylindrical insertion portion that has a positioning end surface that abuts on the opening side end surface, and when the external thread portion and the internal thread portion are screwed together, the internal insertion portion is inserted with a gap with respect to the internal diameter of the internal thread, A pair of the cylindrical insertion portions are disposed on one diameter when viewed from the axial direction, and are capable of radially projecting and retracting in the axial direction at the axial position where the tip can abut against the thread of the female screw. A plurality of sets of stylus provided at a plurality of different positions in the axial direction of the cylindrical insertion portion, and with a phase shift being changed around an axis; It is supported coaxially with the inner diameter of the part so as to be slidable and slidable in the axial direction. Parts located within the inner diameter of, and an inner tubular body having a base end protrudes from the proximal end of the tubular insertion portion,
Within the inner diameter of the inner cylindrical body, the inner cylindrical body is swingably supported by a swing shaft in a direction orthogonal to the axis of the inner cylindrical body, and a tip projects from the tip of the inner cylindrical body into the cylindrical insertion portion, And a pair of lever-shaped link bars whose protruding distal ends are capable of urging the pair of styluses radially outward of the cylindrical insertion portion, and whose base ends protrude from the base end of the inner cylindrical body, A displacement detection device that is supported on the proximal end side of the inner cylindrical body and detects a displacement amount of each of the proximal ends of the pair of link bars protruding from the proximal end; and The above object is achieved.

[Action]

In the present invention, at different axial positions of the internal thread,
Since the displacement amount of a plurality of sets of styluses each arranged on the same diameter can be detected by a displacement detection device via a pair of link bars, without replacing a measuring tool,
The taper and the standoff of the female thread can be easily and reliably detected.

【Example】

Hereinafter, embodiments of the present invention will be described with reference to the drawings. The internal thread measuring device 10 according to this embodiment includes a male thread portion 14 that can be screwed into a part of the internal thread 12 to be measured.
And, when the external thread portion 14 is screwed into the internal thread 12, the external thread portion is provided with a positioning end face 16 which is in contact with the opening side end face 13 A of the thread portion 13 because the internal thread is formed, and the external thread portion 14 and the internal thread 12 are provided.
When screwed, a cylindrical insertion portion 20 inserted into the female screw portion 13 with a gap 18 with respect to the internal diameter of the female screw 12,
The cylindrical insertion portion 20 is disposed on one diameter when viewed from the axial direction, and is capable of freely protruding and retracting in the axial direction in the axial direction where the tip can abut on the ridge of the female screw 12. A pair of styluses 22A and 22B, and styluses 22C and 22D provided with a 90 ° phase shift about the axis of the cylindrical insertion portion 20 with respect to the styluses 22A and 22B, and the cylindrical insertion portion 20. The two sets of stylus and the two sets of stylus 24
A, 24B and 24C, a probe consisting of 24D, and the cylindrical insertion portion 20
The inner diameter 20A of the cylindrical insertion portion 20 is coaxially supported by the inner diameter 20A of the cylindrical insertion portion 20 so as to be slidable and rotatable and slidable in the axial direction.
0A, and the inner cylindrical body 26 whose base end 26B protrudes from the base end 20C of the cylindrical insertion portion 20, and the tip ends 28A, 30A are the pair of styluses 22A, 22B and 22C, 22D or 24A, 24B and 24C, 2
4D can be biased radially outward of the cylindrical insertion portion 20, and a pair of lever-like link bars 28, 30 whose base ends 28B, 30B protrude from the base end of the inner cylindrical body 26, and the inner side A displacement detection device 32 that is supported on the base end 26B side of the tubular body 26 and detects a displacement amount of each base end 28B, 30B of the pair of link bars 28, 30 protruding from the base end 26B. This is a configuration of a female screw measuring device. The displacement detection device 32 is a normal digital dial gauge configured to detect the displacement of the base ends 28B, 30B of the pair of link bars 28, 30. The digital outputs of the digital dial gauges 32A and 32B are output to the hand-held computer 36 via the measurement data transmission cables 34A and 34B. The male screw part 14 of the cylindrical insertion part 20 is formed with a small thread at a position adjacent to the distal end side from the positioning end face 16. This is because even if the inner diameter of the measured internal thread 12 near the open end face 13A is the minimum limit of the dimensional variation, the screw can be screwed in, and the measured open end face 13A of the internal thread 12 and the measuring device This is to ensure that the positioning end faces 16 of the 10 abut. A stylus 22A supported on the distal end 20B side by the cylindrical insertion portion 20,
As shown in FIG. 1, 22B, 22C and 22D are arranged offset by half a pitch of the female screw 12 in the axial direction of the cylindrical insertion portion 20. Further, the styluses 22A and 22C are arranged offset by 1/4 pitch of the female screw 12. This is because the styluses 22A, 22B and 22C, 22D are
In order to be able to contact the mountains. Therefore, when the female screw 12 is, for example, a double thread, a half-pitch offset is not required for the pair of styluses 22A, 22B and 22C, 22D. A pair of styluses 24A, 24B and 2 on the proximal end 20C side of the cylindrical insertion portion 20
Similarly, 4C and 24D are also offset by half a pitch of the female screw 12 in the axial direction of the cylindrical insertion portion 20. Here, in FIG. 1, two pairs of styluses 22A, 22B and
Although only 24A and 24B are shown, as shown in FIG.
Stylus 22C, 22D and 24C, 24D are stylus 22A, 22B and 24A, 24B
The phase is shifted by 90 ° around the central axis of the cylindrical insertion section 20 with respect to the cylindrical insertion section 20 (see FIG. 2). Furthermore, in this embodiment, two pairs of styluses 22A and 22B
The distance between 24A and 24B is set to 1 inch so that the taper calculation described later is convenient. The styluses 22A, 22B and 22C, 22D and 24A, 24B and 24C, 24D
Both are slidably held in a cylindrical holder 23 screwed into the cylindrical insertion portion 20, and are urged in the central axis direction of the cylindrical insertion portion 20 by a spring 23A. . That is, under normal conditions, the styluses 22A, 22B, 22C, 22D, 24A, 24B, 24
The tips of C and 24D are set to the most retracted positions. The position of each stylus in the center direction of the cylindrical insertion portion 20 is regulated by a flange portion 23B formed integrally with the stylus in the cylindrical insertion portion 20,
It is configured to contact the bottom surface 23C of the hole formed for inserting the holder 23. The end of each stylus on the center side of the cylindrical insertion portion 20 protrudes inward from the inner diameter 20A of the cylindrical insertion portion 20. The tips 28A, 30A of the pair of link bars 28, 30 are the styluses 22A and 22B and 22C and 22D or 24A and 24B and 24C and 24D
Equal to the axial offset amount of the cylindrical insertion portion 20,
It is offset in the axial direction. Both ends of a support shaft 29 that swingably supports the pair of link bars 28 and 30 are supported by the inner cylindrical body 26. From this support shaft 29, the digital dial gauge 32
The distance between A and 32B to the contacts 33A and 33B is slightly larger than the distance from the support shaft 29 to the tips 28A and 30A. The pair of digital dial gauges 32A, 32B are pivotally movable via pins 31A, 31B at the distal ends of support fittings 27A, 27B protruding radially outward from a base end 26B of the inner cylindrical body 26. Supported. Therefore, when not in use, the digital dial gauges 32A and 32B are flipped up about the pins 31A and 31B so that the contacts 33A and 33B are kept in non-contact with the link bars 28 and 30. ing. As shown in FIG. 2, the outer periphery of the cylindrical insertion portion 20 is a cylindrical outer peripheral surface having a diameter smaller than the minimum inner diameter of the female screw 12. The mounting position of the holder 23 is chamfered in a flat shape so that the outer end and the female screw 12 do not interfere with each other. In addition, the outer periphery of the inner cylindrical body 26 is a cylindrical outer peripheral surface so as to be adjacent to the inner diameter 20A of the cylindrical insertion portion 20, but the stylus 22A, 22B and 22C, 22D or 24A, 24B and 24
To prevent interference with the inner ends of C and 24D, two pairs of facing portions 26C and 26D are formed, respectively. A total of six positioning recesses 38 are formed on the cylindrical outer peripheral surface of the inner cylindrical body 26 at two positions spaced apart in the axial direction at equal angular intervals of 90 ° around the central axis. ing. The axial positions of these positioning recesses 38 are such that the tips 28A, 30A of the pair of link bars 28, 30 are stylus 22A, 22B or 22.
C, 22D, when located at a position where it can come into contact with the base end, the positioning spring plunger 40 screwed to the base end 20B, which is outside the positioning end face 16 of the tubular insertion portion 20 and outside the female screw 12, The position where the tip of fits, and the link bar 28,
When the distal ends 28A, 30A of the 30 are at positions where they can come into contact with the base ends of the styluses 24A, 24B or 24C, 24D, the distal ends of the positioning spring plungers 40 are adapted to be fitted positions. The handle-held computer 36 includes a digital signal output from the digital dial gauges 32A and 32B, and a preset distance between the four sets of styluses (1 inch in this embodiment), a link bar 28, 30, the distance from the support shaft 29 to the distal end 28A, 30A and the proximal contacts 33A, 33B
The taper, the stand-off, and the effective diameter of the female screw 12 are calculated based on the ratio of the distance to the contact point (lever ratio). Next, a process of measuring and detecting the taper, the stand-off and the effective diameter of the female screw 12 by the above embodiment will be described with reference to FIG. First, the cylindrical insertion portion 20, the inner cylindrical body 26 and the link bar 2
The measuring device 10 including 8 and 30 is inserted into a master gauge (not shown) whose inner diameter has been measured in advance, and is set therein (step 101). 22A and 22B are extruded so that the tips come into contact with the inner diameter of the master gauge, and in this state, zero adjustment of the digital dial gauges 32A and 32B is performed (step 102). Next, the measuring device 10 is inserted into the female screw 12 to be measured, and the male thread portion 14 of the cylindrical insertion portion 20 is screwed into the female screw 12 until the positioning end face 16 contacts the opening side end face 13A. (Step 103). At this time, the inner cylindrical body 26 is
The tips 28A and 30A of the link bars 28 and 30 are set in advance so as to be located at the positions of the styluses 22A and 22B (Position 1-0).
゜). In this state, the contacts 33A, 33B of the digital dial gauges 32A, 32B are brought into contact with the base ends 28B, 30B of the link bars 28, 30 from both sides. Digital dial gauge 32A, 32B contacts 33A, 33B
Is biased by a spring so that a predetermined measurement pressure can be obtained, so that the base ends 28B and 30B are pushed in a direction in which both approach. The pressing force at this time is based on the principle of leverage.
The tip 28A, 30A of the tip 28A, 30A is transmitted to the tip 28A, 30A so that the stylus 22A, 22B projects radially outward against the spring 23A. Since the tip positions of the styluses 22A and 22B coincide with the ridges of the internal thread 12, the tip ends of the
Abut each mountain. The measured values of the digital dial gauges 32A and 32B at this time are read by the handheld computer 36 (step
104). Next, the inner tubular body 26 is pulled out of the tubular insertion portion 20 by a distance of 1 inch outward. After being pulled out by one inch, the positioning spring plunger 40 fits into the positioning recess 38 located at this axial position, and the operator moves the tip 28 of the link bar 28, 30.
It is known that A and 30A have reached the base positions of the styluses 24A and 24B (Position 2-0). Next, in the same manner as described above, the digital dial gauge
Connect the contacts 33A, 33B of 32A, 32B to the base end 28 of the link bar 28, 30.
B and 30B, the contact pressure causes the link bar
The tip 28A, 30B of 28, 30 pushes the base end of the stylus 24A, 24B,
This is made to project outward. Therefore, the styluses 24A and 24B abut against the ridges of the female screw 12 at positions different from the above by one inch in the axial direction. The digital dial gauges 32A and 32B in this state
Is read by the handheld computer 36 (step 104). Next, the inner cylindrical body 26 is rotated by 90 ° about the axis. At this time, the displacement device support bar 27 to which the displacement detection devices 32A and 32B are attached abuts on the rotation direction positioning stopper 21B attached to the tubular insertion portion 20, and the inner tubular body 26 is moved relative to the measurement position. Notice that the 90 ° phase shift has shifted around the axis. When the inner cylindrical body 26 is inserted by one inch in this state, the positioning spring plunger 40 fits into the positioning recess 38 in the axial direction (Position 1-90 °). Next, the output values of the digital dial gauges 32A and 32B at the positions of the styluses 22C and 22D are measured in the same manner as in the measurement position (Position 1-0).
Is read (step 104). Next, the inner tubular body 26 is pulled outward by a distance of 1 inch with respect to the tubular body insertion portion 20. After being pulled out by one inch, the positioning spring plunger 40 is fitted into the positioning concave portion 38 in the axial direction, and the operator holds the tips 28A, 30A of the link bars 28, 30 with the bases of the styluses 24C, 24D. Know that it has reached the end position (Position 2-90 °). Next, the output values of the digital type dial gauges 32A and 32B at the positions of the styluses 24C and 24D are measured in the same manner as in the measurement position (Position 2-0).
Reading is performed by 36 (step 104). The hand-held computer 36 obtains the positions 1-0 °, 1- 1 from the previously input lever ratios of the link bars 28, 30, the length of the stylus, and the measurement values of the master gauge.
The inner diameter of the female screw 12 at 90 °, 2-0 ° and 2-90 ° is calculated (step 105). Here, in the positions 1-0 ° and 1-90 ° and in the positions 2-0 ° and 2-90 °, since the link bars 28 and 30 are displaced by 90 ° around the axis, the female screw 12 has one thread. If it is a screw, a shift in the 1/4 pitch axis direction occurs. Therefore, the calculated inner diameter value is interpolated by a 1/4 pitch shift to calculate the inner diameter value at the reference position of each position (1 and 2) (step 106). Next, the average inner diameters D ₁ and D ₂ of the respective positions 1 and 2 are calculated (step 106). Next, as described above, the distance L ₂ between the positions 1 and ₂ is 1
Since the distance is inches, the taper Te = D ₂ −D ₁ / L as shown in FIG. 5 (A) from this distance and the average inner diameters D ₁ and D ₂ at the positions 1 and 2 determined above. Ask for ₂ (Step 108). Next, as shown in FIG. 5 (B), the effective diameter D _{0 of the} screw is determined by the distance L from the positioning end face 16 to the position 2.
_{Based on 1} and the distance L from the positioning end face 16 to the reference position of the screw and the above-mentioned D ₁ and D ₂ , the formula D ₀ = (L ₁ + L ₂ −L)
/ L ₂ · (D ₂ −D ₁ ) (step 109). Next, as shown in FIG.
D ₀ and a reference effective diameter D _0K, the reference taper Te _K, standoff = S (D _0K -D ₀₎ Request / Te _K (step 110). Then, the tapered Te, as compared with a preset allowable value measurements of the effective diameter D ₀ and standoff S determines acceptability of the internal thread (step 111), further, the measured values and acceptance judgment result Print out from printer 42 (step 11
2). After the printout, the measuring device 10 is detached from the female thread portion 13 to complete the measurement (Step 113). Next, a description will be given of an embodiment of a measuring device for measuring the parallel portion 12A at the innermost portion of the internal thread shown in FIGS. This embodiment differs from the embodiment shown in FIGS. 1 to 3 only in the structure of the terminal comprising the stylus, and the other parts are the same as those in the first embodiment. First
The description is omitted by attaching the same reference numerals as those in FIGS. In this embodiment, the styluses 44A and 44B are
Are fixedly mounted on the outer periphery of the distal ends of the levers 46A and 46B which are swingably supported by the pins 48 in the outer grooves 50A and 50B. The pair of grooves 50A, 50B are, as shown in FIG.
They are arranged opposite to each other on the same diameter, and are formed to be long in the axial direction of the cylindrical insertion portion 20. The ends of the levers 46A and 46B on the side opposite to the styluses 44A and 44B are urged radially outward by springs 54A and 54B via urging pins 52A and 52B. Therefore, the tips of the levers 46A, 46B on the side of the styluses 44A, 44B are
The springs 54A and 54B press the grooves 50A and 50B against the bottom surfaces. Further, a through hole 56 formed in the cylindrical insertion portion 20 is provided at a position between the pin 48 and the stylus 44A, 44B of the lever 46A, 46B.
Fixing pins 58A and 58B whose tips project from the inside diameter 20A of the cylindrical insertion portion 20 through A and 56B are attached. The positions of the fixing pins 58A and 58B and the through holes 56A and 56B are as follows.
The link bars 28, 30 are disposed at positions corresponding to the tips 28A, 30A. The stylus 44A, 44B has a lever 46A, 46B with a spring 54A, 54B.
Female thread 12 and its parallel parts when biased by
When the bases 28B, 30B of the link bars 28, 30 are pushed out by the contacts 33A, 33B of the digital dial gauges 32A, 32B, the links are pulled out into the grooves 50A, 50B so as not to interfere with 12A. When the fixing pins 58A and 58B are pushed up by the tips 28A and 30A of the bars 28 and 30, the stylus 44 is
A and 44B can contact the parallel portion 12A. The measuring mechanism for the parallel part 12A consisting of the stylus, the lever, the pin, the groove, the biasing pin, the spring, the through hole and the fixing pin is shown in FIG. 7 in addition to the one shown in FIG. In addition, a component having a similar configuration is disposed at a position shifted by 90 ° from the center axis of the cylindrical insertion portion 20. However, with respect to the through holes 56A, 56B and the fixing pins 58A, 58B, the through holes 66A, 66B and the fixing pins 68A, 68B are arranged so as to be shifted by 1/4 pitch in the axial direction of the cylindrical insertion portion 20, respectively. . In this embodiment, the inner diameter of two places is measured simply by rotating the link bars 28, 30 without moving them in the axial direction, and the diameter of the parallel portion 12A can be measured from the average value. In the above embodiment, the digital dial gauges 32A and 32B are used as the displacement detection devices.
The present invention is not limited to this. If necessary, it is sufficient that the displacement of the link bars 28, 30 can be detected. Therefore, for example, the displacement may be obtained from the swing angle of the link bars 28, 30. It may be one that has been made. Also, instead of using a digital dial gauge, it may be calculated from a read value of an analog dial gauge.

【The invention's effect】

Since the present invention is configured as described above, it has an excellent effect that the taper and the stand-off of the internal thread can be easily and reliably measured without changing the gauge.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of a female thread measuring device according to the present invention, FIG. 2 is a sectional view taken along the line II-II of FIG.
Fig. 4 is a left side view of the embodiment of Fig. 1, Fig. 4 is a flow chart showing the process of measuring the inner diameter from the embodiment, Fig. 5 is a schematic sectional view showing a measuring point, and Fig. FIG. 7 is a sectional view taken along the line VII-VII of FIG. 6, and FIG. 8 is a sectional view showing a main part of the embodiment in an enlarged manner. 10: Female thread measuring device, 12: Female thread, 13: Female thread, 13A: Open end face, 14: Male thread, 16: Positioning end face, 18: Gap, 20 ... Cylindrical insertion part, 20A …… Inner diameter, 20C …… Basic end, 22A, 22B, 24A, 24B …… Touch, 26 …… Inner cylindrical body, 26A …… Tip, 26B …… Basic end, 28, 30 …… Link bar, 28A, 30A …… Tip, 28B, 30B …… Basic end, 29 …… Support shaft, 32 …… Displacement detector, 32A, 32B …… Digital dial gauge, 36… Handheld computer.

Claims (1)

(57) [Claims] 1. A thread part which can be screwed into a part of a female thread to be measured, and a thread part which is formed when said male thread is screwed into said female thread. A positioning end face that abuts the opening side end face of the female thread portion, and when the external thread portion and the internal thread are screwed together, a cylindrical insertion portion inserted with a gap with respect to the internal diameter of the internal thread in the internal thread portion. The cylindrical insertion portion is disposed on one diameter when viewed from the axial direction, and is axially movable in the radial direction at an axial position where the tip can abut against the thread of the female screw. A pair of stylus is set as a set, a plurality of sets of stylus provided at a plurality of different positions in the axial direction of the cylindrical insertion portion, and changing the phase shift around the axis, and the cylindrical probe On the inner diameter of the insertion part, coaxially, supported slidably and slidably in the axial direction,
An inner tubular body having a distal end located within the inner diameter of the tubular insertion portion, and a base end projecting from the proximal end of the tubular insertion portion; and the inner tubular body within the inner diameter of the inner tubular body. Is pivotably supported by a pivot shaft in a direction perpendicular to the axis of the inner cylindrical body. A pair of lever-like link bars whose base ends protrude from the base end of the inner cylindrical body, and are supported on the base end side of the inner cylindrical body; A displacement detection device that detects a displacement amount of a base end of each of the pair of link bars protruding from an end,
An internal thread measuring device comprising: