A method and a measuring instrument for comprehensive measurement of parameters of a taper pipe thread

Abstract

The application discloses a kind of taper pipe thread parameter comprehensive measuring method and measuring instrument, and the two tooth side data of thread groove in different positions are obtained by measuring head, the measurement datum point coordinates of each measuring head are determined according to tooth side data, and the parameters of thread are determined according to the measurement datum point coordinates of measuring head and tooth side measurement data, the method adopts contact type measuring method, realizes the taper of outer thread pipe outer thread, pitch, top diameter, ellipse, tooth type angle, tooth top height, tooth type height seven parameters, and is suitable for circular thread and trapezoidal thread, and the several parameters of the outer thread of the measured taper pipe thread are directly displayed by digital display, greatly improve measurement efficiency.

Description

Technical Field

[0001] This invention belongs to the field of oil pipe metering, specifically a method and instrument for measuring the thread parameters of an externally threaded pipe. Background Technology

[0002] Oil pipes are subjected to combined external loads downhole, making their threaded connections highly susceptible to failure. Therefore, it is essential to inspect the thread parameters. Taper, pitch, major diameter, ellipticity, thread angle, crest height, and thread profile height are some of the main thread parameters. Each parameter has a corresponding individual measuring instrument, and each parameter needs to be measured using these instruments.

[0003] The existing methods for measuring the external threads of oil pipes have the following problems: each parameter measurement requires a corresponding single measuring instrument, manual operation is time-consuming, and the positioning, measurement accuracy, and measurement efficiency of automatic measurement all need to be improved. Summary of the Invention

[0004] To address the problems existing in the prior art, this invention provides a comprehensive measurement method and instrument for tapered pipe thread parameters, which can simultaneously measure seven parameters of tapered pipe external threads, including taper, pitch, major diameter, ellipticity, thread angle, thread crest height, and thread profile height, without changing the measuring tools, thus greatly improving measurement efficiency.

[0005] This invention is achieved through the following technical solution:

[0006] A comprehensive measurement method and instrument for tapered pipe thread parameters, characterized by comprising the following steps:

[0007] Step 1: Construct a measurement coordinate system with the center of the end of the threaded pipe as the origin;

[0008] Step 2: Insert all four probes into the thread groove and make contact with the tooth sides of the thread groove respectively. Take the spatial coordinate values ​​of the probes at this moment as a set of measurement data. Repeat this process so that the probes form two contact points with each of the two tooth sides of the thread groove, and obtain a total of four sets of data.

[0009] Step 3: Calculate the spatial coordinate position of the corresponding thread groove mid-diameter based on the four sets of data, and use it as the measurement reference position of the probe;

[0010] Step 4: Determine the various parameters of the thread based on the measurement reference coordinates of each probe.

[0011] Preferably, in step 1, the X-axis of the coordinate system is the axis of the threaded pipe, and the Y-axis is the vertical radial direction of the threaded pipe.

[0012] Preferably, in step 2, the four probes are divided into two groups, with the two probes in each group located in the threaded groove of the threaded pipe cross-section.

[0013] Preferably, the two probes in each group are symmetrically arranged along the central axis of the threaded pipe.

[0014] Preferably, the thread parameters in step 4 include thread taper, pitch, major diameter, ellipticity, and thread angle.

[0015] Preferably, the spatial coordinates (x, y) of the measurement reference position of the probe are set. s1 y s1 ,0), (x s2 y s2 ,0), (x s3 y s3 ,0), (x s4 y s4 ,0);

[0016]

[0017]

[0018] Where i represents the i-th probe.

[0019] Preferably, the taper and pitch of the threaded groove are as follows:

[0020] The taper is:

[0021]

[0022] The pitch is:

[0023]

[0024] Where A is the number of teeth within a distance a of the circular thread.

[0025] Preferably, the mean diameter of the thread is:

[0026]

[0027] j = 3, k = 2 or j = 4, k = 1;

[0028] The ellipse of the thread is:

[0029] D = H max -H min

[0030] The thread angle is:

[0031]

[0032] Preferably, the method further includes the following steps: obtaining the spatial coordinates of the tooth tip of the thread tooth, and determining the tooth tip height and tooth profile height by combining the measurement reference coordinates of the probe.

[0033] A measuring instrument for a comprehensive measurement method of tapered pipe thread parameters includes a telescopic rod, an adjustment mechanism, a measuring rod, a measuring head, a control console, and a measuring unit;

[0034] Two probes are mounted parallel and spaced apart on the adjusting mechanism. Each probe has two probes spaced along its axial direction and located on the same plane. The side probes on the two probes are positioned opposite each other and are used to extend into the thread groove. The adjusting mechanism can control the two probes to move radially along the oil pipe. The fixed plate is connected to one end of the telescopic rod, and the other end of the telescopic rod is connected to the control console. The control console is used to control the telescopic rod to move axially. The measuring unit is connected to the control console and receives the measurement data from the side probes.

[0035] Compared with the prior art, the present invention has the following beneficial technical effects:

[0036] This invention provides a comprehensive measurement method and instrument for tapered pipe thread parameters. It acquires data on the two sides of the thread groove at different positions using a probe, determines the measurement reference coordinates of each probe based on the flank data, and then determines the thread parameters based on the probe's measurement reference coordinates and the flank measurement data. This method employs a contact measurement approach to measure seven parameters of the tapered pipe external thread: taper, pitch, major diameter, ellipticity, thread angle, crest height, and thread profile height. It is applicable to both round threads and trapezoidal threads, and these parameters are directly displayed on a digital display, greatly improving measurement efficiency. Attached Figure Description

[0037] Figure 1 This is a schematic diagram of the measuring instrument of the present invention;

[0038] Figure 2 This is a data acquisition sequence diagram of the circular thread tooth side in Embodiment 1 of the present invention;

[0039] Figure 3 This is a diagram showing the movement trajectory of the probe in Embodiment 1 of the present invention;

[0040] Figure 4 This is a schematic diagram illustrating the measurement principle of the circular thread in Embodiment 1 of the present invention;

[0041] Figure 5 This is a schematic diagram of the measurement reference position of the probe in Embodiment 1 of the present invention;

[0042] Figure 6 This is a data acquisition sequence diagram of the trapezoidal thread teeth in Embodiment 2 of the present invention;

[0043] Figure 7 This is a schematic diagram illustrating the measurement principle of the trapezoidal thread teeth in Embodiment 2 of the present invention;

[0044] Figure 8 This is a schematic diagram of the measurement reference position of the probe in Embodiment 2 of the present invention.

[0045] In the diagram, 1-telescopic rod; 2-positioning plate; 3-measuring rod; 4-probe; 5-control console; 6-digital display panel; 7-workbench; 8-computer and data processing software; 9-acquisition system. Detailed Implementation

[0046] The present invention will now be described in further detail with reference to the accompanying drawings. These descriptions are intended to explain the invention and not to limit it.

[0047] See Figure 1 and 2 A comprehensive measuring instrument for tapered pipe thread parameters includes a telescopic rod 1, an adjustment mechanism 2, a measuring rod 3, a measuring head 4, a control console 5, and a measuring unit.

[0048] Two measuring rods are mounted parallel and spaced apart on the adjusting mechanism 2. Each measuring rod 3 has two measuring heads 4 spaced along its axial direction, and the two measuring heads 4 are located on the same plane. The side heads on the two measuring rods are arranged opposite each other and are used to extend into the thread groove. The adjusting mechanism 2 can control the two measuring rods to move radially along the oil pipe. The fixing plate is connected to one end of the telescopic rod 1, and the other end of the telescopic rod is connected to the control console 5. The control console 5 is used to control the telescopic rod to move along its axial direction. The measuring unit is connected to the control console and receives the measurement data from the side heads.

[0049] The measurement unit includes a data processing unit 8, a display panel 6 and an acquisition system 9 connected thereto. The acquisition system 9 is connected to the side head. The display panel 6 is used to display measurement results and analysis results. The control console is set on the workbench 7.

[0050] The initial distance between the two probes on the same probe rod is 25.4 mm (1 inch). The probe moves along the axial direction of the probe rod with a range of 0–20 mm, which can be adjusted according to the actual application. For example, a groove is provided on the probe rod, and the probe connection end is positioned in the groove to move and adjust the position of the probe.

[0051] The aforementioned probe is a contact probe, which is used as a measuring sensor to contact the thread teeth. When measuring each point, the probe (usually ruby) makes a displacement after contacting the workpiece being measured, and the sensor outputs a signal simulating the displacement to the measuring unit.

[0052] The adjustment mechanism 2 is equipped with a transmission device, which is connected to the measuring rod 3 and is used to drive the measuring rod to move up and down so that the measuring head enters the thread groove. For example, in a screw-slider mechanism, the measuring rod is connected to the slider, the slider is connected to the screw, the screw is set vertically and connected to the motor, the motor drives the screw to rotate, thereby driving the slider to move, and synchronously driving the measuring rod to move.

[0053] Example 1

[0054] See Figure 2-5 The following section uses a round thread as an example to describe in detail a method for measuring the thread parameters of an externally threaded pipe provided by this invention, including the following steps:

[0055] Step 1: Adjust the distance between the two measuring rods so that the distance between the two measuring rods is greater than the outer diameter of the threaded pipe being tested. Then, abut and fix the end face of the threaded end being tested against the end face of the positioning plate. This can also be understood as making the axial direction of the threaded pipe being tested coaxial with the axis of the telescopic rod 1, while making the measuring rod parallel to the axis of the threaded pipe being tested. Set the center of the end circle of the threaded pipe being tested as the origin of the spatial coordinate system, with the X-axis parallel to the axial direction of the threaded pipe and the Y-axis parallel to the vertical radial direction of the threaded pipe.

[0056] Step 2: Control the two measuring rods to move towards each other through the control unit, so that all four probes are inserted into the thread groove and contact the tooth side of the thread respectively. The spatial coordinate value of the probe at this moment is used as a set of measurement data. Repeat this process so that the probe forms two contact points with each tooth side of the thread, and four sets of measurement data are obtained.

[0057] The spatial coordinates of the first group of four probes are as follows: (x 11 y 11 ,0), (x 12 y 12 ,0)(x 13 y 13 ,0)(x 14 y 14 ,0).

[0058] The spatial coordinates of the second group of four probes are as follows: (x 21 y 21 ,0), (x 22 y 22 ,0)(x 23 y 23 ,0)(x 24 y 24 ,0).

[0059] The spatial coordinates of the third group of four probes are as follows: (x 31 y 31 ,0), (x 32 y 32 ,0)(x 33 y 33 ,0)(x 34 y 34 ,0).

[0060] The spatial coordinates of the four probes in the fourth group are as follows: (x 41 y 41 ,0), (x 42 y 42,0)(x 43 y 43 ,0)(x 44 y 44 ,0).

[0061] See Figure 2 The four probes on both sides of the measuring rod contact the outer edge of the external thread, and the spatial coordinates of the centers of the four probes are recorded to form the first set of measurement data. Then, the probes are moved along the thread axis towards the other end of the thread, and the probe coordinates are recorded upon contact, forming the second set of measurement data. The probes are then moved obliquely upwards or downwards (at an angle α) to contact the other thread side, and the probe coordinates are recorded upon contact, forming the third set of measurement data. Finally, the probes are moved again to contact the other thread side, and the probe coordinates are recorded upon contact, forming the fourth set of measurement data.

[0062] Figure 2-1 First, place the probe against the upper side of the left tooth. Figure 2-2 The probe is moved horizontally to fit against the upper side of the right tooth. Figure 2-3 The probe moves obliquely to fit against the lower side of the left tooth. Figure 2-4 The probe is moved horizontally to fit against the lower side of the right tooth. Figure 3 The following are four sets of data showing the movement trajectory of the probe during the measurement process:

[0063] The spatial coordinates of the first group of four probes are as follows: (x 11 y 11 ,z0),(x 12 y 12 ,z0)(x 13 y 13 ,z0)(x 14 y 14 ,z0).

[0064] The spatial coordinates of the second group of four probes are as follows: (x 21 y 21 ,z0),(x 22 y 22 ,z0)(x 23 y 23 ,z0)(x 24 y 24 ,z0).

[0065] The spatial coordinates of the third group of four probes are as follows: (x 31 y 31 ,z0),(x 32 y 32 ,z0)(x 33 y 33 ,z0)(x 34 y 34 ,z0).

[0066] The spatial coordinates of the four probes in the fourth group are as follows: (x 41 y 41 ,z0),(x 42 y 42 ,z0)(x 43 y 43 ,z0)(x 44 y 44 ,z0).

[0067] Step 3: Use the center diameter of the thread groove corresponding to the probe as the measurement reference position for the probe, and determine the measurement reference position coordinates for each probe based on the four sets of data obtained. (See also...) Figure 4 , which represents the geometric relationship between the two references located on the thread taper, pitch, thread pitch diameter, and ellipse.

[0068] The spatial coordinates of the measurement reference positions of the four probes are set as (x... s1 y s1 ,0), (x s2 y s2 ,0), (x s3 y s3 ,0), (x s4 y s4 ,0).

[0069]

[0070]

[0071] Where i represents the i-th probe, i = 1, 2, 3, 4, y i2 Let Y be the Y-coordinate of the i-th probe in the second set of data.

[0072] Step 4: Determine the thread taper, pitch, major diameter, ellipticity, and thread angle based on the measurement reference coordinates of each probe. (See also...) Figure 5 The geometric relationship between the probe reference position and the tooth angle, tooth crest height, and tooth height.

[0073] The taper is:

[0074]

[0075] The pitch is:

[0076]

[0077] A represents the number of teeth in 1 inch (25.4 mm) of the round thread;

[0078] The median diameter is:

[0079]

[0080] j = 3, k = 2 or j = 4, k = 1;

[0081] The ellipse is:

[0082] D = H max -H min

[0083] The tooth angle is:

[0084]

[0085] Where x and y are the spatial coordinates of the probe on the guide surface and the bearing surface.

[0086] The data processing system calculates the measurement reference position, the probe moves to the measurement reference position, the probe extends out of the horizontal plate and contacts the corresponding thread tooth tip on the 2nd tooth side, and the spatial coordinates of the contact point are recorded.

[0087] Step 5: Obtain the spatial coordinates of the two symmetrical tooth tips of the thread teeth at the same axial section position, and determine the tooth tip height and tooth profile height by combining them with the measurement reference coordinates of the probe.

[0088] The spatial coordinates of the two tooth tips are (x p1 y p1 ,0), (x p2 y p2 If ,0), then the methods for determining the tooth crest height and tooth profile height are as follows:

[0089] Tooth crest height is:

[0090]

[0091] Tooth height is:

[0092]

[0093] Where R is the probe radius and r is the radius of the circular thread root arc for each specification.

[0094] Example 2

[0095] See Figure 6-8 A comprehensive measurement method and instrument for tapered pipe thread parameters, comprising the following steps:

[0096] Step 1: Set the end center of the threaded pipe to be tested as the origin of the spatial coordinate system. The X-axis is parallel to the axial direction of the threaded pipe, and the Y-axis is parallel to the vertical radial direction of the threaded pipe.

[0097] Step 2: During measurement, adjust the measuring rod to be parallel to the axis of the external thread. When the four probes on both sides of the measuring rod contact the root of the trapezoidal external thread, record the spatial coordinates of the centers of the four probes (first group). Move the probe towards the tooth side of the bearing surface, and record the probe coordinates after contact (second group). Move the probe further towards the thread root, and record the probe coordinates after contact (third group). Finally, move the probe towards the tooth side of the bearing surface again, and record the probe coordinates after contact (fourth group).

[0098] Step 3: Use the center diameter of the thread groove corresponding to the probe as the measurement reference position of the probe, and determine the measurement reference position coordinates of each probe based on the four sets of data obtained.

[0099] Step 4: Determine the thread taper, pitch, major diameter, ellipticity, and tooth profile angle based on the measurement reference coordinates of each probe. The calculation method is the same as in Example 1 and will not be repeated here.

[0100] Step 5: Obtain the spatial coordinates of the thread tooth tip, and determine the tooth tip height and tooth profile height by combining them with the measurement reference coordinates of the probe.

[0101] The tooth angle is:

[0102]

[0103] Tooth height is:

[0104] H j =|y D1 -y S1 |

[0105] The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solution based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. A comprehensive measurement method for tapered pipe thread parameters, characterized in that, Includes the following steps: Step 1: Construct a measurement coordinate system with the center of the end of the threaded pipe as the origin; Step 2: Insert all four probes into the thread groove and make contact with the tooth side of the thread groove respectively, and take the spatial coordinate value of the probe at the current moment as a set of measurement data; The measurement process was repeated so that the probe formed two contact points with each of the two tooth sides of the thread groove, resulting in a total of four sets of data. Step 3: Calculate the spatial coordinate position of the corresponding thread groove mid-diameter based on the four sets of data, and use it as the measurement reference position of the probe; The spatial coordinates of the measurement reference points of the measuring head (x s1 , y s1 , 0), (x s2 , y s2 , 0), (x s3 , y s3 , 0), (x s4 , y s4 , 0) are set. in, Representing the One probe; Step 4: Determine the various parameters of the thread based on the measurement reference coordinates of each probe.

2. The method for comprehensive measurement of tapered pipe thread parameters according to claim 1, characterized in that, In step 1, the X-axis of the coordinate system is the axis of the threaded pipe, and the Y-axis is the vertical radial direction of the threaded pipe.

3. The method for comprehensive measurement of tapered pipe thread parameters according to claim 1, characterized in that, In step 2, the four probes are divided into two groups, with the two probes in each group located in the threaded groove of the threaded pipe cross-section.

4. The method for comprehensive measurement of tapered pipe thread parameters according to claim 3, characterized in that, The two probes in each group are symmetrically arranged along the central axis of the threaded pipe.

5. The method for comprehensive measurement of tapered pipe thread parameters according to claim 3, characterized in that, The thread parameters mentioned in step 4 include thread taper, pitch, major diameter, ellipticity, and thread angle.

6. The method for comprehensive measurement of tapered pipe thread parameters according to claim 1, characterized in that, The taper and pitch of the threaded groove are as follows: The taper is: The pitch is: Where A is a circular thread. Number of teeth within a distance.

7. The method for comprehensive measurement of tapered pipe thread parameters according to claim 5, characterized in that, The mean diameter of the thread is: j=3, k=2 or j=4, k=1; The ellipse of the thread is: The thread angle is: 。 8. The method for comprehensive measurement of tapered pipe thread parameters according to claim 1, characterized in that, It also includes the following steps: obtaining the spatial coordinates of the tooth tip of the thread tooth, and determining the tooth tip height and tooth profile height by combining the measurement reference coordinates of the probe.

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