A production method for preventing cross-threading of oil casing coupling with conical threads at both ends

Abstract

The invention relates to a production method for preventing cross-threading of an oil casing coupling with tapered threads at both ends, and relates to the technical field of oil casing couplings. The method comprises a coupling fixing step and a thread processing tool adjustment and correction step. The coupling is fixed by using a fixed chuck or an automatic flip chuck. The invention realizes the same spiral line when processing threads at both ends quickly and accurately, thereby avoiding the cross-threading phenomenon at the middle cutting position of the threads at both ends of the joint, effectively improving the qualified rate of the product, being economical and effective, saving time and labor, and being applicable to both the fixed chuck and the automatic flip chuck of the machine tool.

Description

Technical Field

[0001] The present invention relates to the technical field of oil casing couplings, and specifically, to a production method for preventing cross-threading of oil casing couplings with tapered threads at both ends. Background Art

[0002] Currently, in the domestic and foreign oil well pipe product manufacturing industries, a coupling with tapered threads of the same model and specification at both ends is often processed. In the currently most commonly used processing method, the threads at both ends are processed separately, so it is difficult to ensure that the threads at both ends are on the same helix. This is manifested in the product morphology as cross-threading at the tool-changing position between the tapered threads at both ends, resulting in unqualified products. Summary of the Invention

[0003] The purpose of the present invention is to provide a production method for preventing cross-threading of oil casing couplings with tapered threads at both ends, which quickly and accurately realizes the same helix during the processing of the threads at both ends, thereby avoiding cross-threading at the tool-changing position between the threads at both ends of the joint, effectively improving the qualified rate of products, and being economical, effective, time-saving and labor-saving, and applicable to both the machine tool fixed chuck and the automatic flipping chuck.

[0004] To achieve the above purpose, the technical solution adopted by the present invention is as follows: A production method for preventing cross-threading of oil casing couplings with tapered threads at both ends, including the steps of fixing the coupling and adjusting and correcting the thread processing tool. The fixing of the coupling is by using a fixed chuck or an automatic flipping chuck.

[0005] As an optimized solution,

[0006] The method for fixing the coupling with the fixed chuck includes the following steps:

[0007] 1.1. Draw a through and axis-parallel marking line on the outer circumference of the coupling along the axis direction of the coupling;

[0008] 1.2. Make a first marking point or a first marking line on the chuck: Make a marking point at any circumferential position on the end face of the fixed chuck for clamping the coupling or a marking line diverging outward perpendicular to the chuck axis;

[0009] 1.3. Clamp the coupling sample to be processed with threads onto the fixed chuck, ensuring that the marking line made on the coupling in step 1.1 is aligned with the first marking point or the first marking line made on the chuck in step 1.2, and clamp firmly.

[0010] As an optimized solution,

[0011] The method for fixing the coupling with the fixed chuck includes the following steps:

[0012] 1.1. Draw a through and axis-parallel marking line on the outer circle of the coupling along the axis direction of the coupling;

[0013] 1.2. Make a second marking point or second marking line on the chuck: When the chuck stops locking, make a marking point or a marking line that diverges outward perpendicular to the chuck axis on the chuck end face closer to the operator on the plane of the moving trajectory of the thread tool tip, that is, make a marking point or line at the specified position.

[0014] 1.3. Clamp the coupling of the thread to be machined onto the fixed chuck, ensuring that the marking line made in step 1.1 is aligned with the second marking point or second marking line made on the chuck in step 1.2, and clamp it firmly.

[0015] As an optimized solution,

[0016] The method for the automatic flipping chuck to fix the coupling includes the following steps: Position and clamp the coupling in the direction of the rotation center line of the automatic flipping chuck, and the positioning point should ensure that the flipping center of the flipping chuck is at the midpoint position of the coupling length.

[0017] As an optimized solution,

[0018] The flipping axis of the automatic flipping chuck must be within the plane of the thread tool.

[0019] As an optimized solution,

[0020] The steps for adjusting and correcting the thread machining tool include the following steps:

[0021] 2.1. Zero the thread tool for machining the opposite taper threads at both ends of the coupling with the outer end face of the coupling to determine the zero position reference of the tool.

[0022] 2.2. Zero correction of the thread machining tool:

[0023] (1) Offset the zero position reference of the tool backward by 2 - 10 mm as the zero point for the tool to start turning, so as to ensure that the thread tool meets the machining requirements during machining and is convenient for machining operations. Then program the thread machining program as required to machine the thread at the first end.

[0024] (2) After machining the thread at the first end, loosen the chuck and replace it to machine the other end. When replacing, the clamping position of the coupling and the fixed chuck is the same as that in step 1.3. At this time, there is no need to adjust the tool zero point, and directly use the programmed thread machining program to machine the thread at the second end.

[0025] After machining the threads at both ends, measure the thread pitch at both ends along the axis at any position inside the coupling to obtain the value L1.

[0026] Use the following formula to calculate the thread tool adjustment value:

[0027] a = (L1 - A * p) / 2

[0028] Wherein: a is the adjustment value of the threading tool (mm);

[0029] p is the thread pitch value (mm);

[0030] A is an integer. When selecting A, the absolute value of L1 - A*p should be minimized;

[0031] If a is negative, the positioned threading tool is adjusted by |a| value in the direction away from the workpiece; if a is positive, the positioned threading tool is adjusted by |a| value in the direction close to the workpiece;

[0032] Correct the zero point of the threading tool, re - machine the sample after adjustment and detect.

[0033] As an optimization scheme,

[0034] The adjustment and correction steps of the threading tool include the following steps:

[0035] 2.1. Use the outer end face of the coupling to zero the threading tools for machining the opposite - end taper threads at both ends of the coupling to determine the tool zero - point reference.

[0036] 2.2. Zero - point correction of the threading tool:

[0037] (1) Measure the total length L1 of the coupling to be machined;

[0038] (2) Calculate the adjustment value of the threading tool using the following formula:

[0039] a = (L1 - A*p) / 2

[0040] Wherein: a is the adjustment value of the threading tool (mm);

[0041] p is the thread pitch value (mm);

[0042] A is an integer. When selecting A, the absolute value of L1 - A*p should be minimized;

[0043] If a is negative, the positioned threading tool is adjusted by |a| value in the direction away from the workpiece; if a is positive, the positioned threading tool is adjusted by |a| value in the direction close to the workpiece;

[0044] Correct the zero point of the threading tool, machine the sample and detect.

[0045] The present invention adopts the above - mentioned technical solutions and has the following advantages:

[0046] 1. It quickly and accurately realizes the same helix during the threading of both ends, thus avoiding the thread - jamming phenomenon at the tool - changing position between the threads at both ends of the joint, effectively improving the product qualification rate, and is economical, effective, time - saving and labor - saving, and is applicable to both the machine - tool fixed chuck and the automatic flipping chuck;

[0047] 2. The rapid machining and debugging of workpieces on the machine tool are realized, the debugging time is reduced, and the production efficiency of the assembly line is effectively improved.

[0048] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments. Description of the Drawings

[0049] Figure 1 It is a schematic cross-sectional structure diagram of an oil casing coupling with tapered threads at both ends of the present invention;

[0050] Figure 2 It is a schematic structure diagram of the marked straight line on the outer circumference of the coupling in Embodiments 1 and 2 of the present invention;

[0051] Figure 3 It is a schematic structure diagram of the first marked point or the first marked line on the fixed chuck in Embodiment 1 of the present invention;

[0052] Figure 4 It is a schematic structure diagram of the first marked point or the first marked line on the fixed chuck in Embodiment 2 of the present invention.

[0053] In the figure,

[0054] 1 - coupling, 2 - tapered thread, 3 - marked straight line, 4 - first marked point, 5 - first marked line, 6 - second marked point, 7 - second marked line, 8 - plane of the moving track of the thread tip, 9 - fixed chuck. Specific Embodiments

[0055] Next, in combination with the embodiments of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0056] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, "a plurality" means two or more, unless otherwise specifically defined. Embodiment 1

[0057] As Figures 1-3 shown, a production method for preventing cross-threading of an oil casing coupling with tapered threads at both ends includes a fixing step of the coupling and an adjustment and correction step of the thread machining tool.

[0058] The collar is fixed by using a fixed chuck. The method of fixing the collar with a fixed chuck includes the following steps:

[0059] 1.1. Draw a continuous and axis - parallel marking line 3 along the axis direction on the outer circumference of the collar.

[0060] 1.2. Make a first marking point 4 or a first marking line 5 on the chuck: Make a marking point at any circumferential position on the end face of the fixed chuck for clamping the collar or a marking line that diverges outward perpendicular to the chuck axis.

[0061] 1.3. Clamp the collar sample to be threaded onto the fixed chuck, ensuring that the marking line 3 made on the collar in step 1.1 is aligned with the first marking point 4 or the first marking line 5 made on the chuck in step 1.2, and clamp it firmly.

[0062] The steps for adjusting and correcting the threading tool include the following steps:

[0063] 2.1. Zero the threading tool for machining the opposing taper threads at both ends of the collar using the outer end face of the collar to determine the zero - position reference of the tool.

[0064] 2.2. Zero - position correction of the threading tool:

[0065] (1) Shift the zero - position reference of the tool backward by 2 - 10 mm as the zero point for the tool to start turning, so as to ensure that the threading tool meets the processing requirements during machining and is convenient for machining operations. Then, program the threading process according to the requirements to machine the threads at the first end.

[0066] (2) After machining the threads at the first end, loosen the chuck, replace the machining end. When replacing, the clamping position of the collar and the fixed chuck is the same as in step 1.3. At this time, there is no need to adjust the tool zero point, and directly use the programmed threading process to machine the threads at the second end.

[0067] After machining the threads at both ends, measure the thread pitch between the threads at both ends (the pitch between any tooth groove machined at the first end and any tooth groove machined at the second end) at any position along the axis inside the collar to obtain the value L1.

[0068] Calculate the threading tool adjustment value using the following formula.

[0069] a = (L1 - A * p) / 2

[0070] Where: a is the threading tool adjustment value (mm).

[0071] p is the thread pitch value (mm).

[0072] A is an integer. When selecting A, make the absolute value of L1 - A * p the smallest.

[0073] If a is negative, adjust the positioned threading tool away from the workpiece by |a| value; if a is positive, adjust the positioned threading tool towards the workpiece by |a| value.

[0074] Correct the zero point of the threading tool, reprocess the sample after adjustment and conduct inspection.

[0075] Cross-threading will no longer occur in the middle of the reprocessed sample, and the product is qualified. Embodiment 2

[0076] As Figures 1-2 shown in FIGS. 3 and 4, a production method for preventing cross-threading of a casing coupling with tapered threads at both ends includes a fixing step of the coupling and an adjusting and correcting step of the threading tool.

[0077] The coupling is fixed by using a fixed chuck. The method for fixing the coupling with the fixed chuck includes the following steps:

[0078] 1.1. Draw a continuous marking line 3 parallel to the axis along the outer circumference of the coupling in the axial direction of the coupling.

[0079] 1.2. Make a second marking point 6 or a second marking line 7 on the chuck: When the chuck stops locking, make a marking point or a marking line diverging outward perpendicular to the chuck axis on the chuck end face closer to the operator in the plane 8 of the moving trajectory of the threading tool tip, that is, make a marking point or a line at the specified position.

[0080] 1.3. Clamp the coupling to be threaded onto the fixed chuck, ensuring that the marking line 3 made on the coupling in step 1.1 is aligned with the second marking point 6 or the second marking line 7 made on the chuck in step 1.2, and clamp it firmly.

[0081] The adjusting and correcting step of the threading tool includes the following steps:

[0082] 2.1. Zero the threading tool for machining the opposite tapered threads at both ends of the coupling with the outer end face of the coupling to determine the zero position reference of the tool.

[0083] 2.2. Zero position correction of the threading tool:

[0084] (1) Measure the total length L1 of the coupling to be machined.

[0085] (2) Calculate the threading tool adjustment value using the following formula.

[0086] a = (L1 - A * p) / 2

[0087] Where: a is the threading tool adjustment value (mm).

[0088] p is the thread pitch value (mm).

[0089] A is an integer. When selecting A, make the absolute value of L1 - A*p the smallest.

[0090] If a is negative, adjust the positioned threading tool away from the workpiece by |a| value; if a is positive, adjust the positioned threading tool towards the workpiece by |a| value.

[0091] Correct the zero point of the threading tool, machine a sample part and conduct inspections.

[0092] There will no longer be thread jamming in the middle of the machined sample part, and the product is qualified.

[0093] Example 2 saves more time and sample parts than Example 1, but has fixed position requirements for the chuck positioning points or the marked positions of the positioning lines. The production site can select and implement according to the actual situation. Example 3

[0094] A production method for preventing cross-thread jamming of a casing coupling with tapered threads at both ends includes a fixing step for the coupling and an adjustment and correction step for the threading tool.

[0095] The fixing of the coupling is by automatic flipping chuck fixing, including the following steps: Position and clamp the coupling in the direction of the rotary center line of the automatic flipping chuck. The positioning point should ensure that the flipping center of the flipping chuck is at the midpoint position of the coupling length. There are no special requirements for the position between the flipping axis of the automatic flipping chuck and the plane of the threading tool.

[0096] The adjustment and correction step for the threading tool includes the following steps:

[0097] 2.1. Zero the threading tool for machining the opposite tapered threads at both ends of the coupling with the outer end face of the coupling to determine the tool zero position reference.

[0098] 2.2. Zero position correction of the threading tool:

[0099] (1) Shift the tool zero position reference backward by 2 - 10 mm as the zero point for the tool to start turning, so as to ensure that the threading tool meets the machining requirements and is convenient for machining operations during machining. Then, program the threading machining program as required to machine the threads at the first end.

[0100] (2) After machining the threads at the first end, directly machine the second end after the chuck flips. At this time, there is no need to adjust the tool zero point, and directly use the programmed threading machining program to machine the threads at the second end.

[0101] After machining the threads at both ends, measure the thread pitch at both ends (the pitch between any tooth groove machined at the first end and any tooth groove machined at the second end) in any position along the axis inside the coupling to obtain the value L1.

[0102] Use the following formula to calculate the threading tool adjustment value.

[0103] a = (L1 - A * p) / 2

[0104] Where: a is the adjustment value of the threading tool (mm).

[0105] p is the thread pitch value (mm).

[0106] A is an integer. When selecting A, the absolute value of L1 - A * p should be minimized.

[0107] If a is negative, adjust the positioned threading tool away from the workpiece by |a| value; if a is positive, adjust the positioned threading tool towards the workpiece by |a| value.

[0108] Correct the zero point of the threading tool, re - machine the sample after adjustment and inspect.

[0109] There will be no more thread jamming in the middle of the re - machined sample, and the product is qualified. Example 4

[0110] A production method for preventing cross - thread jamming of an oil - casing coupling with tapered threads at both ends includes a fixing step of the coupling and an adjustment and correction step of the threading tool.

[0111] The fixing of the coupling is to use an automatic flipping chuck for fixing, including the following steps: position and clamp the coupling along the rotation center line direction of the automatic flipping chuck. The positioning point should ensure that the flipping center of the flipping chuck is at the mid - point position of the coupling length, and the flipping axis of the automatic flipping chuck must be within the plane of the threading tool.

[0112] The adjustment and correction step of the threading tool includes the following steps:

[0113] 2.1. Zero the threading tool for machining the opposite - facing tapered threads at both ends of the coupling with the outer end face of the coupling to determine the zero - point reference of the tool.

[0114] 2.2. Zero - point correction of the threading tool:

[0115] (1) Measure the total length L1 of the coupling to be machined.

[0116] (2) Calculate the adjustment value of the threading tool using the following formula.

[0117] a = (L1 - A * p) / 2

[0118] Where: a is the adjustment value of the threading tool (mm).

[0119] p is the thread pitch value (mm).

[0120] A is an integer. When selecting A, the absolute value of L1 - A * p should be minimized.

[0121] If a is negative, adjust the positioned threading tool away from the workpiece by |a| value; if a is positive, adjust the positioned threading tool towards the workpiece by |a| value.

[0122] Correct the zero point of the threading tool, machine the sample part and conduct inspection.

[0123] Thread disorder will no longer occur in the middle of the machined sample part, and the product is qualified.

[0124] Example 4 saves more time and sample parts than Example 3, but has special requirements for the position of the flipping axis of the automatic flipping chuck. Its flipping axis needs to be within the moving plane of the threading tool, and it can be selected and implemented according to the actual situation at the production site.

[0125] In summary, set the distance between the two-end threads as an integer multiple of the specified thread pitch of the thread, and thread disorder will no longer occur after the two-end threads are machined.

[0126] Finally, it should be noted that the above are only the preferred embodiments of the present invention and are not used to limit the present invention. Examples of implementation methods, parts not described in detail therein are all common general knowledge of those of ordinary skill in the art. For those skilled in the art, they can still modify the technical solutions recorded in the foregoing embodiments or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A production method for preventing cross-threading of oil casing couplings with tapered threads at both ends, characterized in that: It includes the steps of fixing the coupling and adjusting and correcting the thread processing tool; The thread machining tool adjustment and correction step comprises the following steps: 2.

1. The thread cutter for processing the top cone threads at both ends of the coupling uses the outer end face of the coupling to zero and determine the tool zero position reference; 2.

2. Zero position correction of thread machining tool: (1) The tool zero reference is offset 2-10 mm backward as the zero point for the tool to start turning, to ensure that the thread tool meets the processing requirements and is convenient for processing operations, and then compile the thread processing program as required to process the thread at the first end; (2) After processing the first end thread, loosen the chuck and replace it to process the other end. When replacing, the clamping position of the coupling and the fixed chuck is the same as in step 1.

3. At this time, there is no need to adjust the tool zero point, and the second end thread can be directly processed using the prepared thread processing program; (3) After the threads at both ends are processed, measure the thread spacing at both ends along the axial direction at any position inside the coupling to obtain the value L1; (4) Use the following formula to calculate the thread tool adjustment value: a=(L1-A*p) / 2 Where: a is the thread tool adjustment value (mm); p is the thread pitch value (mm); A is an integer. When selecting A, the absolute value of L1-A*p should be minimized; If a is a negative value, the positioned thread tool is adjusted by the value |a| in the direction away from the workpiece; if a is a positive value, the positioned thread tool is adjusted by the value |a| in the direction close to the workpiece; (5) Correct the thread tool zero point, reprocess the sample after adjustment and inspect it.

2. The method for producing a coupling for oil casing with tapered threads at both ends to prevent cross-threading according to claim 1, characterized in that: The coupling is fixed by using a fixing chuck. The method of fixing the coupling by the fixing chuck includes the following steps: 1.

1. Draw a straight line (3) on the outer periphery of the coupling that runs through the coupling and is parallel to the axis. 1.

2. Make a first marking point (4) or a first marking line (5) on the chuck: make a marking point or a marking line that diverges perpendicular to the axis of the chuck at any position on the end surface of the fixed chuck of the clamping coupling; 1.

3. Clamp the coupling sample to be processed with threads onto the fixed chuck, ensuring that the marking straight line (3) made on the coupling in step 1.1 is aligned with the first marking point (4) or the first marking line (5) made on the chuck in step 1.2, and clamp it securely.

3. The method for producing a coupling for oil casing with tapered threads at both ends to prevent cross-threading according to claim 1, characterized in that: The coupling is fixed by using an automatic flip chuck. The method of fixing the coupling by the automatic flip chuck includes the following steps: positioning and clamping the coupling in the direction of the rotation center line of the automatic flip chuck. The positioning point must ensure that the flip center of the flip chuck is the midpoint of the coupling length.

4. A production method for preventing cross-threading of oil casing couplings with tapered threads at both ends, characterized in that: It includes the steps of fixing the coupling and adjusting and correcting the thread processing tool; The thread machining tool adjustment and correction step comprises the following steps: 2.

1. The thread cutter for processing the top cone threads at both ends of the coupling uses the outer end face of the coupling to zero and determine the tool zero position reference; 2.

2. Thread machining tool zero position correction: (1) Measure the total length L1 of the coupling to be processed; (2) Use the following formula to calculate the thread tool adjustment value: a=(L1-A*p) / 2 Where: a is the thread tool adjustment value (mm); p is the thread pitch value (mm); A is an integer. When selecting A, the absolute value of L1-A*p should be minimized; If a is a negative value, the positioned thread tool is adjusted by the value |a| in the direction away from the workpiece; if a is a positive value, the positioned thread tool is adjusted by the value |a| in the direction close to the workpiece; (3) Correct the thread tool zero point, process the sample and inspect it.

5. The method for producing a coupling for oil casing with tapered threads at both ends to prevent cross-threading according to claim 4, characterized in that: The coupling is fixed by using a fixing chuck. The method of fixing the coupling by the fixing chuck includes the following steps: 1.

1. Draw a straight line (3) on the outer circle of the coupling that runs through the coupling and is parallel to the axis. 1.

2. Make a second marking point (6) or a second marking line (7) on the chuck: when the chuck stops locking, make a marking point or a marking line that diverges outwards perpendicular to the chuck axis on the chuck end surface close to the operator on the moving trajectory plane (8) of the thread cutter tip, that is, make a marking point or line at a designated position; 1.

3. Clamp the coupling to be threaded onto the fixed chuck, ensuring that the marking straight line (3) made on the coupling in step 1.1 is aligned with the second marking point (6) or the second marking line (7) made on the chuck in step 1.2, and clamp it securely.

6. The method for producing a coupling for oil casing with tapered threads at both ends to prevent cross-threading according to claim 4, characterized in that: The coupling is fixed by using an automatic flip chuck, and the flip axis of the automatic flip chuck must be in the plane of the thread tool.

Images