Screw drill tool rotor polishing wheel and design method thereof

Abstract

A kind of screw drill rotor polishing wheel and its design method.The main core disc of the polishing wheel of the present application, elastomer layer, polishing abrasive layer are sequentially fixedly connected from inside to outside;The main core disc is a metal part, the elastomer layer is of rubber material, the elastomer layer is fixed as a whole with the main core disc by rubber adhesive and rubber vulcanization process;The polishing abrasive layer is fixedly bonded with the elastomer layer by adhesive;The generatrix of the surface polishing curve of the polishing abrasive layer is consistent with a section of the profile line of the normal section;The design method of the polishing wheel is based on three-dimensional modeling software according to the rotor design size.The beneficial effects are that the polishing wheel structure is simple and easy to process;The polishing wheel design method is simple and easy to execute, the surface of the polishing wheel and the rotor surface design size are highly consistent, the rotor helical surface can be accurately processed, the rotor surface processing quality is improved, the motor leakage is reduced, the motor volumetric efficiency is improved, the motor performance is improved, so as to improve the design and manufacturing level of screw drill.

Description

Technical Field

[0001] This invention relates to a screw drill rotor processing device, and more particularly to a screw drill rotor polishing wheel and its design method, belonging to the field of petroleum drilling technology. Background Technology

[0002] A screw drill is a positive displacement downhole power drill that uses drilling fluid as its power source to convert fluid pressure energy into mechanical energy. The motor assembly of a screw drill mainly consists of a stator and a rotor. The outer surface curve of the rotor is machined through milling, polishing, and surface coating. The stator has one more head than the rotor. After the rotor is installed in the stator, any section perpendicular to the axis is taken, and both are conjugately meshed. Therefore, there is a series of meshing points on the left-hand screw around the axis. These meshing points enclose a sealed cavity with a fixed volume. As the rotor moves within the stator, the sealed cavity gradually moves along the axis, discharging the energy-converted mud from the low-pressure chamber of the motor.

[0003] The precision of the rotor surface curve is a crucial factor determining the performance of a screw drill motor. Strict requirements are placed on the rotor's surface profile and dimensional accuracy. After milling, noticeable tool marks remain, necessitating polishing. Currently, polishing of the rotor surface is mostly done using abrasive belts or grinding wheels. However, mechanical polishing equipment has limited freedom of movement, only allowing the grinding wheel assembly to move up and down. This prevents precise polishing of the complex helical surface of the screw drill rotor, leading to problems such as leakage, unstable performance, and low efficiency during motor operation.

[0004] The existing rotor polishing wheels are designed with the rotor end section profile in mind, ensuring a proper fit between the wheel and the rotor end section. However, due to the helix angle on the rotor's helical surface, the wheel needs to feed along the helical groove for polishing. Since there's a certain angle (helix angle) between the wheel profile and the rotor end section, the wheel must swing a certain angle (helix angle) from its initial position to align with the helical groove direction. This results in a mismatch between the wheel and the helical surface. Because the current rotor polishing design is flawed, significant errors occur in the machining of the rotor surface profile during the process. Summary of the Invention

[0005] To overcome the shortcomings of existing methods that use grinding wheels to polish the outer surface of rotors, such as the mismatch between the grinding wheel surface shape and the rotor's spiral surface leading to significant errors in rotor profile machining, and the resulting leakage, unstable performance, and low efficiency in the operation of screw drill motors, this invention provides a screw drill rotor polishing wheel and its design method.

[0006] The technical solution adopted by the present invention to solve its technical problem is: a screw drill rotor polishing wheel, including a main core disk, an elastomer layer and a polishing abrasive layer, which are fixedly connected from the inside to the outside; the main core disk is a metal part, the elastomer layer is made of rubber, and the elastomer layer is fixed to the main core disk as a whole by means of rubber adhesive and rubber vulcanization process; the polishing abrasive layer is fixedly bonded to the elastomer layer by means of adhesive.

[0007] The generatrix L of the polishing wheel surface M3 on the surface of the polishing abrasive layer coincides with a segment of the normal profile T2.

[0008] This invention discloses a method for designing a polishing wheel for a screw drill rotor, comprising a rotor and a polishing wheel. The method is characterized by the following design steps based on 3D modeling software, according to the rotor's design dimensions:

[0009] S1, Create rotor equidistant lines T4.

[0010] S1-1, Create bone line T3.

[0011] The curve obtained by applying the cycloidal equation is the rotor bone line T3, and the X-axis coordinate points and Y-axis coordinate points are:

[0012] Formula 1

[0013] In the formula: θ—roll angle, which is the radian traversed by the radius of the roll circle.

[0014] R a —Guide circle radius

[0015] R b ——Rounding radius

[0016] e — the distance from the moving point to the center of the round circle.

[0017] S1-2, Create equidistant line T4.

[0018] Based on the rotor's major diameter design dimensions, the rotor is offset equidistantly from the outside of the rib line T3. The rotor's major diameter design dimensions are equal to the diameter of the circumcircle of the equidistant line, and the resulting curve is the rotor's equidistant line T4.

[0019] S2. Create the spiral curve T.

[0020] The application software's "helix" function allows you to set the helix angle, helix diameter, pitch, length, and helix direction based on the rotor's design dimensions. The helix diameter is the same as the diameter of the circumscribed circle of the equidistant line T4, and the resulting curve is the rotor's helix T.

[0021] S3. Create the rotor helical surface M.

[0022] The application software's "sweep" function includes: the section line corresponds to the equidistant line T4, the guide line corresponds to the helix T, and the vector direction corresponds to the Z-axis direction.

[0023] S4. Calculate the equation of the rotor theoretical normal plane M2.

[0024] Based on the T-parameter equation of the cylindrical helix

[0025] Formula 2

[0026] Where: t — parameter

[0027] R—Radius of the helix T

[0028] H – Lead of the spiral T

[0029] when The equation of the normal plane at time,

[0030] Differentiate the parametric equation of the helix:

[0031] Formula 3

[0032] when When, then point P(0,R, ), corresponding tangent vector The equation of the theoretical normal plane M2 is:

[0033] Formula 4

[0034] In the formula: X — coordinate point X

[0035] Z—Z coordinate point

[0036] S5. Create the rotor normal plane M2'.

[0037] Passing through point P(0,R, Draw the normal plane M2' of the spiral.

[0038] S6. Create the intersection line between the rotor helical surface M and the normal plane M2'.

[0039] Using the "Intersection Curves" function in the application software, select "Helical Surface M" for the first set of surfaces and "Normal Plane M2'" for the second set of surfaces. Draw the intersection line between the rotor helical surface M and the normal plane M2', which is the normal profile line T2.

[0040] S7. Select three points P, P1, and P2 on the normal contour line T2.

[0041] Take two points on either side of point P: point P1(X1,Y1,Z1) and point P2(X2,Y2,Z2).

[0042] S8. Determine that points P, P1, and P2 all lie on the theoretical normal plane M2.

[0043] Let point P(0,R, Substituting P1(X1,Y1,Z1) and P2(X2,Y2,Z2) into the equations of the theoretical normal plane M2, we get:

[0044]

[0045] If the three equations are equal, then the normal plane M2' is coplanar with the theoretical normal plane M2.

[0046] S9. Create a polishing wheel.

[0047] S9-1. On the normal contour line T2 of the intersection of the rotor helical surface M and the normal plane M2', select the highest point P' of one helical head of the rotor and the lowest point of the two symmetrical helical grooves on both sides, and take the curve segment between the two lowest points, including point P', as the generatrix L of the polishing wheel.

[0048] S9-2. Using the generatrix L as the cross-sectional curve, the polishing wheel surface M3 is formed by applying the "rotation" function of the software.

[0049] Furthermore, in step S1-2, the distance of the equidistant offset to the outside of the rib line T3 is half of the rotor's major diameter design size minus the radius of the circumscribed circle of the rib line.

[0050] The beneficial effects of this invention are that the polishing wheel has a simple structure and is easy to process; the polishing wheel design method is simple and easy to implement; the design dimensions of the polishing wheel surface and the rotor surface have a high degree of fit; it can accurately process the rotor helical surface, improve the rotor surface processing quality, reduce motor leakage, improve motor volumetric efficiency, and enhance motor performance, thereby improving the design and manufacturing level of screw drill tools. Attached Figure Description

[0051] Figure 1 This is a schematic diagram of the rotor polishing wheel of the screw drill of the present invention.

[0052] Figure 2 This is a schematic diagram illustrating the principle of modeling the surface curve of the polishing wheel in this invention.

[0053] Figure 3 yes Figure 2 The left view.

[0054] Figure 4 yes Figure 3 A bottom view.

[0055] Figure 5 This is a schematic diagram of the normal contour line T2 of the present invention and the surface curve of the polishing wheel.

[0056] Figure 6 This is a schematic diagram showing the relationship between the bone line, equidistant line, and rotor diameter in this invention.

[0057] In the diagram: 10. Polishing abrasive layer, 20. Elastomer layer, 30. Main core disk, 40. Rotor major diameter, 50. Rotor, 60. Polishing wheel, 70. Outer diameter circle of the rib line. Detailed Implementation

[0058] The present invention will be further described below with reference to the accompanying drawings and embodiments. However, those skilled in the art should understand that the present invention is not limited to the specific embodiments listed, and any embodiment that conforms to the spirit of the present invention should be included within the scope of protection of the present invention.

[0059] See appendix Figure 1 This invention discloses a polishing wheel for a screw drill rotor, comprising a main core disk 30, an elastomer layer 20, and a polishing abrasive layer 10. The main core disk 30, elastomer layer 20, and polishing abrasive layer 10 are sequentially fixedly connected from the inside to the outside. The main core disk 30 is a metal component, and the elastomer layer 20 is made of rubber. The elastomer layer 20 is fixed to the main core disk 30 as a whole by means of a rubber adhesive and a rubber vulcanization process. The polishing abrasive layer 10 is fixedly bonded to the elastomer layer 20 by an adhesive. A segment of the generatrix L of the polishing wheel curved surface M3 on the surface of the polishing abrasive layer 10 coincides with a segment of the normal contour line T2.

[0060] The present invention discloses a design method for a polishing wheel of a screw drill rotor, which is a parametric design based on equations from three-dimensional modeling software according to the rotor design dimensions. The design dimensions of the rotor 50 include: the guide circle radius, the rolling circle radius, the distance from a fixed point on the rolling circle to the center of the rolling circle, the rotor major diameter, and the radius of the circumscribed circle of the rib line, etc.

[0061] See appendix Figure 2-6 In this design method, the helical surface M is the rotor surface formed by the parallel movement of the rotor equidistant lines along the helical line T; the cross-sectional plane M1 is a plane perpendicular to the rotor axis; the theoretical normal plane M2 is a normal plane obtained through theoretical calculation; the normal plane M2'; the polishing wheel surface M3 is the surface of the polishing wheel 60, formed by rotating the generatrix L of the polishing wheel; the helical line T is the helical line of the rotor; the cross-sectional profile T1 is the intersection line formed by the cross-sectional plane M1 and the helical surface M; the normal profile T2 is the intersection line formed by the normal plane M2' and the helical surface M; the rib line T3 is the basic line for designing the rotor equidistant lines, and is a closed curve that meets the motor sealing requirements; the equidistant line T4 is a closed curve formed by the rib line T3 being offset outwards at equal intervals; the generatrix L is the generatrix of the polishing wheel 60, and is part of the intersection line formed by the intersection of the helical surface M and the normal plane M2'; point P is any point on the helical line T.

[0062] The design method for the polishing wheel of the screw drill rotor includes a rotor 50 and a polishing wheel 60, and the steps are as follows.

[0063] S1, Create rotor equidistant lines T4

[0064] S1-1, Create bone line T3

[0065] The curve obtained by applying the cycloidal equation is the rotor bone line T3, and the X-axis coordinate points and Y-axis coordinate points are:

[0066] Formula 1

[0067] In the formula: θ—roll angle, which is the radian traversed by the radius of the roll circle.

[0068] R a —Guide circle radius

[0069] R b ——Rounding radius

[0070] e — the distance from the moving point to the center of the round circle.

[0071] S1-2, Create equidistant lines T4

[0072] Based on the rotor's major diameter design dimension of 40, an equidistant offset is made outward from the rib line T3. The rotor's major diameter design dimension of 40 is equal to the diameter of the circumcircle of the equidistant line, resulting in the curve T4 of the rotor (see Appendix). Figure 6 ).

[0073] Furthermore, the distance equidistantly offset from the outside of the bone line T3 is half of the rotor's major diameter 40 design size minus the radius of the circumscribed circle of the bone line. The outer diameter circle 70 of the bone line is the circumscribed circle of the bone line, where all vertices of the bone line lie on the same circumference.

[0074] S2, Create a spiral curve T

[0075] The application software's "helix" function allows you to set the helix angle, helix diameter, pitch, length, and helix direction based on the rotor's design dimensions. The helix diameter is the same as the diameter of the circumscribed circle of the equidistant line T4, and the resulting curve is the rotor's helix T.

[0076] S3, Create rotor helical surface M

[0077] The application software's "sweep" function includes: the section line corresponds to the equidistant line T4, the guide line corresponds to the helix T, and the vector direction corresponds to the Z-axis direction.

[0078] S4. Calculate the equation of the rotor theoretical normal plane M2.

[0079] Based on the T-parameter equation of the cylindrical helix

[0080] Formula 2

[0081] Where: t — parameter

[0082] R—Radius of the helix T

[0083] H – Lead of the spiral T

[0084] when The equation of the normal plane at time,

[0085] Differentiate the parametric equation of the helix:

[0086] Formula 3

[0087] when When, then point P(0,R, ), corresponding tangent vector The equation of the theoretical normal plane M2 is:

[0088] Formula 4

[0089] In the formula: X — coordinate point X

[0090] Z — Z coordinate point.

[0091] S5. Create the rotor normal plane M2'

[0092] Through point P(0,R, ...) on M2 Draw the normal plane M2' of the spiral.

[0093] S6. Create the intersection line between the rotor helical surface M and the normal plane M2'.

[0094] Using the "Intersection Curves" function in the application software, select "Helical Surface M" for the first set of surfaces and "Normal Plane M2'" for the second set of surfaces. Draw the intersection line between the rotor helical surface M and the normal plane M2', which is the normal profile line T2.

[0095] The cross-sectional plane M1 is a plane perpendicular to the rotor axis. The intersection line formed by the cross-sectional plane M1 and the helical surface M is the cross-sectional profile T1. The cross-sectional profile T1 is the basis for the traditional polishing wheel design, and it is different from the normal profile T2.

[0096] S7. Select three points P, P1, and P2 on the normal contour line T2.

[0097] Take two points on either side of point P: point P1(X1,Y1,Z1) and point P2(X2,Y2,Z2).

[0098] S8. Points P, P1, and P2 are all located on the theoretical normal plane M2.

[0099] Let point P(0,R, Substituting P1(X1,Y1,Z1) and P2(X2,Y2,Z2) into the equations of the theoretical normal plane M2, we get:

[0100]

[0101] If the three equations are true and equal, then the normal plane M2' is coplanar with the theoretical normal plane M2.

[0102] S9. Create a polishing wheel.

[0103] S9-1. On the normal contour line T2, which is the intersection of the rotor helical surface M and the normal plane M2', select the highest point P' of one helical head of the rotor and the lowest point of the two symmetrical helical grooves. Take the curve segment between the two lowest points, including point P', as the generatrix L of the polishing wheel (see Appendix). Figure 5 ).

[0104] S9-2. Using the generatrix L as the cross-sectional curve, the polishing wheel surface M3 is formed by applying the "rotation" function of the software.

[0105] Furthermore, the software uses the "rotate" function to rotate the base section line L to form the polishing wheel surface M3. The software uses the "offset" function to offset the polishing wheel surface M3 and the software uses the "thicken" function to thicken the surface. Then, the polishing abrasive layer, elastomer layer, and main core disk are created in sequence to obtain the polishing wheel model.

[0106] The polishing wheel of the screw drill rotor of this invention is easy to manufacture. The design method of the polishing wheel can intuitively verify the accuracy of the created polishing wheel surface, and has a high degree of conformity with the rotor design line, resulting in a precise polishing wheel profile. When solving for the intersection of the helical surface and the normal plane, it can avoid complicated equation solving and calculation errors in the solution process. It is convenient to obtain the machining coordinates of the polishing wheel profile, which facilitates CNC machining programming and writing CNC code, thereby improving rotor machining efficiency, reducing the labor intensity and working time of workers, and saving manpower, material resources and financial resources.

[0107] It should be noted that the above embodiments are examples and not limitations of the present invention, and those skilled in the art will be able to design many alternative embodiments without departing from the scope of the claims of this patent.

Claims

1. A screw-rotor polisher wheel for a screw-rotor drill string, comprising a main core disc, characterized in that: The main core disc, the elastic body layer and the polishing abrasive layer of the polishing wheel are sequentially fixed and connected from inside to outside; the main core disc is a metal piece, the elastic body layer is rubber material, and the elastic body layer is fixed into one with the main core disc through rubber adhesive and rubber vulcanization process; the polishing abrasive layer is fixed and adhered with the elastic body layer through adhesive; The generatrix L of the polishing abrasive layer surface polishing wheel curved surface M3 is in line with a section of the normal profile line T2; On the intersection normal profile line T2 of the rotor helical curved surface M and the normal plane M2', the highest point P' of one helical head of the rotor and the lowest points of the two symmetrical helical grooves are selected, and the curve segment between the two lowest points containing the point P' is the generatrix L of the polishing wheel; The normal plane M2' is obtained by the following method: Based on three-dimensional modeling, S1, creating rotor equidistant line T4, S2, creating helical curve T, S3, creating rotor helical curved surface M, S4, calculating rotor theoretical normal plane M2 equation, S5, creating rotor normal plane M2', the normal plane M2' of the helical line passing through the point P on the rotor theoretical normal plane M2, S6, creating the intersection of the rotor helical curved surface M and the normal plane M2', that is, the normal profile line T2, S7, selecting three points P, P1, P2 on the normal profile line T2, S8, substituting the points P, P1 and P2 into the theoretical normal plane M2 equation respectively, to determine that the points P, P1 and P2 are on the theoretical normal plane M2, then the normal plane M2' is coplanar with the theoretical normal plane M2.

2. A method of designing a polishing wheel for a screw-rotor of a screw-rotor drill string according to claim 1, comprising a rotor, a polishing wheel, characterized in that: According to the rotor design size, the design steps based on three-dimensional modeling software are as follows, S1, creating rotor equidistant line T4, S1-1, creating bone line T3, The curve obtained by applying the cycloid equation is the rotor bone line T3, and the X-axis coordinate point and the Y-axis coordinate point are: Formula 1 In the formula: θ - rolling angle, which is the radian passed by the rolling radius R a — lead-in radius R b — rounding radius e - the distance from the moving point to the center of the rolling circle; S1-2, creating equidistant line T4, According to the rotor major diameter design size, the equidistant line T4 is offset outward at equal distance, the rotor major diameter design size is equal to the diameter of the circumscribed circle of the equidistant line, and the obtained curve is the equidistant line T4 of the rotor; S2, creating helical curve T, According to the rotor design size, the helical line angle, the helical diameter, the pitch, the length and the helical direction are set by applying the "helical line" function of the software, wherein the helical diameter is the same as the diameter of the circumscribed circle of the equidistant line T4, and the obtained curve is the helical line T of the rotor; S3, creating rotor helical curved surface M, Applying the "sweeping" function of the software, wherein: the cross-sectional line corresponds to the equidistant line T4, the guide line corresponds to the helical line T, and the vector direction corresponds to the Z-axis direction; S4, calculating rotor theoretical normal plane M2 equation, Based on the cylindrical helical line T parameter equation, Formula 2 Wherein: t - parameter R - helical line T radius H - helical line T lead When the normal plane equation of the time, Derive the helical line parameter equation: Formula Three Formula Three When , then point P (0, R, ), the corresponding tangent vector , the equation of the theoretical normal plane M2 is: Formula 4 In the formula: X - X coordinate point Z - Z coordinate point S5, creating rotor normal plane M2', Through point P(0,R, ...) on M2 Draw the normal plane M2' of the helix; S6, creating the intersection of the rotor helical curved surface M and the normal plane M2', The intersection curve function of the application software is used, the first group of surfaces is selected as the spiral surface M, and the second group of surfaces is selected as the normal plane M2', to obtain the intersection line of the rotor spiral surface M and the normal plane M2', i.e. the normal contour line T2; S7, selecting three points P, P1 and P2 on the normal contour line T2, Two points are selected on both sides of the point P, i.e. the point P1 (X1, Y1, Z1) and the point P2 (X2, Y2, Z2); S8, determining that the points P, P1 and P2 are on the theoretical normal plane M2, Let point P(0,R, Substituting P1(X1,Y1,Z1) and P2(X2,Y2,Z2) into the equations of the theoretical normal plane M2, we get: ； If the three equations are equal, the normal plane M2' is coplanar with the theoretical normal plane M2; S9, creating a polishing wheel, S9-1, selecting the highest point P' of one spiral head of the rotor and the lowest points of the symmetrical spiral grooves on both sides on the intersection line normal contour line T2 of the rotor spiral surface M and the normal plane M2', and taking the curve segment between the two lowest points and containing the point P' as the generatrix L of the polishing wheel; S9-2, using the generatrix L as a cross-sectional curve, and using the "rotation" function of the application software to form the polishing wheel surface M3.

3. The method of designing a polishing wheel for a screw-rotor of a screw-rotor drill-stem as defined in claim 2, characterized by: The distance of the equal-distance offset to the outside of the bone line T3 in the step S1-2 is one half of the rotor large-diameter design size minus the radius of the bone line circumscribed circle.

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