Rotor, motor and screw drill

Abstract

The invention relates to the technical field of drilling equipment. The invention provides a rotor, a motor and a screw drill. The rotor comprises a rotor body, and the outer surface of the rotor body is a continuous cycloid spiral curved surface; the rotor main body is provided with a first end and a second end which are oppositely arranged, and a first section body, a middle section body and a second section body which are sequentially arranged along the axis direction of the rotor main body; the outer diameter of the first section body is gradually reduced from the first end to the second end, and the outer diameter of the second section body is gradually reduced from the second end to the first end. The problems that an existing screw drill is large in leakage loss and low in efficiency are solved.

Description

Technical Field

[0001] The present application relates to the technical field of drilling equipment, and in particular to a rotor, a motor and a screw drill. Background Art

[0002] The screw drill is an indispensable downhole tool in drilling engineering, and the motor is an important power component of the screw drill. The motor includes a stator and a rotor. Any cross section of the stator and the rotor presents a conjugate cycloid line shape. The number of heads of the stator is one more than that of the rotor, so that several regions are formed between the stator and the rotor. When the high-pressure drilling fluid flows through the working pair of the motor, the water pressure in different regions is different, which drives the rotor to perform a plane planetary motion (that is, it revolves around the stator axis while rotating around its own axis). The rotor axis and the stator axis will not be in a straight line. The distance between the two is called the eccentricity. Due to the existence of the eccentricity, the cross-sectional area of ​​the rotor on the eccentric side is larger than that on the other side. Under the action of the drilling fluid pressure difference ΔP at the inlet and outlet of the motor, a tilting torque M will be formed on the rotor. The torque M will cause the eccentricity of the upper end area of ​​the motor to increase and the eccentricity of the lower end area to decrease, thus destroying the meshing state of the stator and rotor in the ideal state, and also causing the motor to increase leakage and reduce efficiency.

[0003] In the related art, the problem of motor leakage is improved by increasing the number of motor stages. Although this method can improve the sealing performance to a certain extent, the increase in the number of motor stages will also increase the friction resistance, which will reduce the motor efficiency. At the same time, there is also the problem of increased manufacturing difficulty. The lower end of the motor is connected to a high-strength universal shaft. Although the high-strength universal shaft can limit the excessive deviation of the rotor and reset the rotor to a certain extent, it has no effect on the tilt of the upper end of the rotor.

[0004] In the related technology, the stator rubber is also made into a cone to eliminate the eccentricity caused by the tilt of the rotor, but the conical stator has many difficulties in actual processing: for example, the inner hole size of the stator rubber is not easy to measure, so it is impossible to accurately select it; for example, the conical stator requires a conical injection mold core. On the one hand, the conical surface of the conical mold core is not easy to straighten, which causes the stator rubber to skew; on the other hand, the conical mold core is not easy to demold after vulcanization. Summary of the invention

[0005] The present application provides a rotor, a motor and a screw drill to solve the problems of large leakage and low efficiency of existing screw drills.

[0006] The present application provides a rotor, comprising:

[0007] A rotor body, wherein the outer surface of the rotor body is a continuous cycloid spiral surface;

[0008] The rotor body has a first end and a second end that are arranged opposite to each other, and a first segment body, a middle segment body and a second segment body that are arranged in sequence along the axis direction of the rotor body;

[0009] The outer diameter of the first section gradually decreases from the first end to the second end, and the outer diameter of the second section gradually decreases from the second end to the first end.

[0010] The present application provides a rotor, wherein the length of the rotor body is defined as L, the length of the first segment is defined as p*L, and the condition is satisfied: 0<p<1, and the length of the second segment is defined as (1-p)*L.

[0011] The present application provides a rotor, in which the outer diameter of the middle section is defined as a, and the maximum outer diameters of the first section and the second section are both larger than the outer diameter of the middle section by b, and b satisfies the condition 0<b<2mm.

[0012] The present application provides a rotor, wherein any cross section in the first section is defined as S1, and the distance between S1 and the first end is x, 0≤x≤p*L, and the condition is satisfied:

[0013] The present application provides a rotor, wherein any cross section in the second segment is defined as S2, and the distance between S2 and the second end is y, 0≤y≤(1-p)*L, satisfying the following conditions:

[0014]

[0015] The present application provides a rotor, wherein the cycloid spiral surface on the surface of the rotor body can be formed by numerical control machining.

[0016] In a second aspect, the present application provides a motor, comprising a stator and a rotor;

[0017] The rotor comprises a rotor body, and the outer surface of the rotor body is a continuous cycloid spiral surface;

[0018] The rotor body has a first end and a second end that are arranged opposite to each other, and a first segment body, a middle segment body and a second segment body that are arranged in sequence along the axis direction of the rotor body;

[0019] The outer diameter of the first section gradually decreases from the first end to the second end, and the outer diameter of the second section gradually decreases from the second end to the first end.

[0020] The stator is formed with a cavity, the rotor is arranged in the cavity, and the inner wall surface of the cavity is formed with a cycloid spiral surface meshing with the rotor.

[0021] The present application provides a motor, wherein the stator of the motor comprises:

[0022] A housing and a bushing arranged inside the housing, wherein an inner wall surface of the bushing forms a cycloid spiral surface meshing with the rotor.

[0023] In a third aspect, the present application provides a screw drill, comprising a stator and a rotor, wherein the stator is formed with a cavity, and the rotor is arranged in the cavity; the rotor comprises a rotor body, and the outer surface of the rotor body is a continuous cycloid spiral surface;

[0024] The rotor body has a first end and a second end that are arranged opposite to each other, and a first segment body, a middle segment body and a second segment body that are arranged in sequence along the axis direction of the rotor body;

[0025] The outer diameter of the first section gradually decreases from the first end to the second end, and the outer diameter of the second section gradually decreases from the second end to the first end.

[0026] The inner wall surface of the cavity is formed with a cycloid spiral surface meshing with the rotor.

[0027] The above technical solution provided by the embodiment of the present application has the following advantages compared with the prior art:

[0028] By setting the rotor to a double-conical structure with larger outer diameters at both ends and smaller outer diameters in the middle section, the motor can effectively overcome the problem of unsatisfactory meshing state caused by larger eccentricity in the upper end area and smaller eccentricity in the lower end area when working. By optimizing the outer diameter of the rotor body, the rotor and the stator are in an ideal meshing state when meshing, effectively improving the meshing gap between the stator and the two ends of the rotor, reducing motor leakage, improving the volumetric efficiency and output performance of the motor, and thus improving the efficiency of the motor. At the same time, since the size of the rotor outer diameter can be directly processed and measured from the outer surface, it is more convenient to process the inner wall of the stator, and the processing difficulty is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0030] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0031] One or more embodiments are exemplarily described by pictures in the corresponding drawings, and these exemplified descriptions do not constitute limitations on the embodiments. Elements with the same reference numerals in the drawings represent similar elements, and unless otherwise stated, the figures in the drawings do not constitute proportional limitations.

[0032] Figure 1 is a cross-sectional view of an existing motor in the axial direction;

[0033] Figure 2 for Figure 1 A radial cross-sectional view of the motor;

[0034] Figure 3 A cross-sectional view in the axial direction of the motor of the present application;

[0035] Figure 4 Figure 3 A radial cross-sectional view of the motor;

[0036] Figure 5 This is a schematic diagram of the structure of a rotor in one embodiment of the present application;

[0037] Figure 6 It is a schematic diagram of the structure of the rotor in another embodiment of the present application.

[0038] Description of reference numerals:

[0039] 100, motor; 10, rotor; 11, first section; 111, first end; 13, second section; 131, second end; 15, middle section; 20, stator; 21, housing; 23, bushing. DETAILED DESCRIPTION

[0040] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0041] The disclosure below provides many different embodiments or examples to implement different structures of the present invention. In order to simplify the disclosure of the present invention, the parts and settings of specific examples are described below. Of course, they are only examples, and the purpose is not to limit the present invention. In addition, the present invention can repeat reference numbers and / or letters in different examples. This repetition is for the purpose of simplification and clarity, and does not itself indicate the relationship between the various embodiments and / or settings discussed.

[0042] For ease of description, spatial relative terms may be used herein to describe the relative positional relationship or movement of one element or feature relative to another element or feature as shown in the figure, such as "inside", "outside", "inner side", "outer side", "below", "below", "above", "above", "front", "back", etc. Such spatial relative terms are intended to include different orientations of the device in use or operation in addition to the orientation depicted in the figure. For example, if the device in the figure undergoes a position flip or a posture change or a motion state change, then these directional indications also change accordingly, for example: an element described as "below other elements or features" or "below other elements or features" will subsequently be oriented as "above other elements or features" or "above other elements or features". Therefore, the example term "below..." may include both upper and lower orientations. The device may be otherwise oriented (rotated 90 degrees or in other directions) and the spatial relative descriptors used herein are interpreted accordingly.

[0043] In order to solve the technical problem of large leakage and low efficiency of the motor 100 in the prior art, the present application provides a rotor 10, a motor 100 and a screw drill.

[0044] Please refer to Figure 1 and Figure 2 , Figure 1 is a cross-sectional view of the existing motor 100 in the axial direction; Figure 2 for Figure 1 A radial cross-sectional view of the motor 100 in FIG. When high-pressure drilling fluid flows through the working pair of the motor 100, differences in water pressure in different areas occur, which in turn drives the rotor 10 to perform a planar planetary motion, that is, while revolving around the axis of the stator 20, it also rotates around its own axis. The axis of the rotor 10 and the axis of the stator 20 will not be in a straight line. The distance between the two is called the eccentricity. Due to the existence of the eccentricity, the cross-sectional area of ​​the rotor 10 on one side of the eccentricity is larger than that on the other side. Under the action of the drilling fluid pressure difference ΔP at the inlet and outlet of the motor 100, a tilting torque M will be formed on the rotor 10. The torque M will cause the eccentricity of the upper end area of ​​the motor 100 to increase, and the eccentricity of the lower end area to decrease. As shown in FIG. Figure 1 As shown in the figure, in the dotted box on the left side of the top, there is a gap between the rotor 10 and the stator 20, and in the dotted box on the right side of the top, part of the rotor 10 eats into the stator 20, causing a gap between the stator 20 and the rotor, causing leakage, reducing the efficiency of the motor, and affecting the performance output; correspondingly, in the dotted box on the right side of the bottom, there is a gap between the rotor 10 and the stator 20, and in the dotted box on the left side of the bottom, part of the rotor 10 eats into the stator 20, causing a gap between the stator 20 and the rotor, causing leakage, reducing the efficiency of the motor, and affecting the performance output. Figure 2 for Figure 1 In the cross-sectional view of the top of the motor 100 in a certain radial direction, the two dotted circles on the left indicate that there is a gap between the rotor 10 and the stator 20, and the dotted circle on the right indicates that the rotor 10 is embedded in the stator 20. Obviously, this meshing state is not the meshing state of the stator 20 and the rotor 10 in an ideal state, which will cause the leakage of the motor 100 to increase and the efficiency to decrease.

[0045] Reference Figures 3 to 6 , the present application provides a rotor 10, comprising:

[0046] A rotor body, wherein the outer surface of the rotor body is a continuous cycloid spiral surface;

[0047] The rotor body has a first end 111 and a second end 131 which are arranged opposite to each other, and a first segment 11, a middle segment 15 and a second segment 13 which are arranged in sequence along the axis direction of the rotor body;

[0048] The outer diameter of the first section 11 gradually decreases from the first end 111 to the second end 131 , and the outer diameter of the second section 13 gradually decreases from the second end 131 to the first end 111 .

[0049] In the embodiment of the present application, the rotor 10 is set to a double-conical structure with a larger outer diameter at both ends and a smaller outer diameter in the middle section. In this way, when the motor 100 is working, the problem of an unsatisfactory meshing state caused by the larger eccentricity of the upper end area of ​​the motor 100 and the smaller eccentricity of the lower end area is effectively overcome. By optimizing the outer diameter of the rotor body, the rotor 10 is in an ideal meshing state when meshing with the stator 20, effectively improving the meshing clearance between the stator 20 and the two ends of the rotor 10, reducing the leakage of the motor 100, improving the volumetric efficiency and output performance of the motor 100, and thus improving the efficiency of the motor 100. At the same time, since the size of the outer diameter of the rotor 10 can be directly processed and measured from the outer surface, it is more convenient to process the inner wall of the stator 20, and the difficulty of processing is also reduced.

[0050] The first end 111 can be understood as the top of the motor 100 and also the entrance of the motor 100, and the second end 131 can be understood as the bottom of the motor 100 and also the exit of the motor 100. In this embodiment, the outer diameter of the middle section 15 of the rotor 10 is the smallest, and the outer diameters of the first section 11 and the second section 13 gradually increase from the middle section 15 to the two ends, so that the entire rotor 10 forms a cone structure with large ends and small middle.

[0051] It can be understood that this embodiment only demonstrates the simplest linear ratio as an example, but is not limited to this proportional relationship. Other shapes such as parabolas, spline curves, etc. are also included in this patent.

[0052] Please refer to Figure 6 The present application provides a rotor 10, defining the length of the rotor body as L, the length of the first section 11 as p*L, satisfying the condition: 0<p<1, and the length of the second section as (1-p)*L.

[0053] In this embodiment, the length of the first segment 11 is p*L, and the condition is satisfied: 0<p<1, then the length of the second segment 13 is (1-p)*L, and the length of the third segment is a plane and can be ignored. For example, when p is 0.6, the length of the first segment 11 is 0.6L, and correspondingly, the sum of the lengths of the second segment 13 and the middle segment 15 is 0.4L.

[0054] Please refer to Figure 6 The present application provides a rotor 10, defining the outer diameter of the middle section 15 as a, the maximum outer diameters of the first section 11 and the second section 13 are both larger than the outer diameter of the middle section 15 by b, and b satisfies the condition 0<b<2mm.

[0055] In this embodiment, the maximum outer diameters of the first segment 11 and the second segment 13 are both greater than the outer diameter of the middle segment 15 by b, that is, the outer diameters of the top of the first segment 11 and the bottom of the second segment 13 are equal, both changed to a+b.

[0056] In one embodiment, when p takes a value of 0.6, the length of the first segment 11 is 0.6L, and correspondingly, the sum of the lengths of the second segment 13 and the middle segment 15 is 0.4L. At this time, since the length of the first segment 11 is longer than that of the second segment 13, the dimensional change rate of the outer diameter in the second segment 13 is relatively large.

[0057] Please refer to Figure 6 The present application provides a rotor 10, wherein any cross section of the first segment 11 is defined as S1, and the distance between S1 and the first end 111 is x, where 0≤x≤p*L; and the following conditions are satisfied:

[0058]

[0059] The present application provides a rotor 10, wherein any cross section of the second segment 13 is defined as S2, and the distance between S2 and the second end 131 is y, wherein 0≤y≤(1-p)*L, and the condition is satisfied:

[0060] In the above embodiment, the outer diameter of any position of the rotor 10 can be accurately obtained by the above formula, which facilitates subsequent processing and measurement. It should be noted that the cycloid spiral surface on the surface of the rotor 10 in this solution can be accurately processed by a CNC processing program, so that the size of the rotor 10 can be accurately controlled during the entire processing process, thereby improving the processing accuracy of the rotor 10.

[0061] In this solution, the size of the rotor 10 is optimized, such as Figure 3 As shown, in the dotted frame on the left side of the top, the gap between the rotor 10 and the stator 20 has been eliminated, and in the dotted frame on the right side of the top, the rotor 10 eats into the stator 20. Since the bushing 23 of the stator 20 is made of rubber, it can produce a large deformation; correspondingly, in the dotted frame on the right side of the bottom, there is no gap between the rotor 10 and the stator 20. In the dotted frame on the left side of the bottom, the amount of the rotor 10 eating into the stator 20 is less than the amount eaten at the top. Since the bushing 23 of the stator 20 is made of rubber, it can produce a large deformation. Correspondingly, Figure 2 for Figure 1 In a radial cross-sectional view of the top of the motor 100, in the two dotted circles on the left, there is no gap between the rotor 10 and the stator 20, and in the dotted circle on the right, the amount of the rotor 10 eating into the stator 20 is small. Through improvement, the meshing state between the rotor 10 and the stator 20 can be close to the ideal state, which effectively improves the leakage problem of the motor 100, improves the volumetric efficiency and output performance of the motor 100, and thus improves the efficiency of the motor 100.

[0062] In a second aspect of the present application, a motor 100 is further provided, the motor 100 comprising a stator 20 and a rotor 10;

[0063] The rotor 10 comprises a rotor body, the outer surface of which is a continuous cycloid spiral surface; the rotor body has a first end 111 and a second end 131 which are arranged opposite to each other, and a first segment 11, an intermediate segment 15 and a second segment 13 which are arranged in sequence along the axis direction of the rotor body;

[0064] The outer diameter of the first segment 11 gradually decreases from the first end 111 to the second end 131, and the outer diameter of the second segment 13 gradually decreases from the second end 131 to the first end 111. The stator 20 is formed with a cavity, and the rotor 10 is disposed in the cavity. The inner wall surface of the cavity is formed with a cycloid spiral surface meshing with the rotor 10.

[0065] In this embodiment, the stator 20 includes a housing 21 and a bushing 23 disposed inside the housing 21, and the inner wall surface of the bushing 23 forms a cycloidal spiral surface meshed with the rotor 10. The housing 21 can be a metal housing 21, and the bushing 23 is made of rubber, and the bushing 23 and the housing can be bonded by vulcanization. By setting the rotor 10 to a double-conical structure with a larger outer diameter at both ends and a smaller outer diameter in the middle section, the motor 100 can effectively overcome the problem of an unsatisfactory meshing state caused by the larger eccentricity of the upper end area of ​​the motor 100 and the smaller eccentricity of the lower end area when working. By optimizing the outer diameter of the rotor body, the rotor 10 is in an ideal meshing state when meshing with the stator 20, effectively improving the meshing clearance between the two ends of the stator 20 and the rotor 10, reducing the leakage of the motor 100, and improving the volumetric efficiency and output performance of the motor 100, thereby improving the efficiency of the motor 100. At the same time, since the outer diameter of the rotor 10 can be directly processed and measured from the outer surface, it is more convenient to process the inner wall of the stator 20, and the difficulty of processing is also reduced.

[0066] The motor 100 in the embodiment of the present application includes the above-mentioned rotor 10, and the specific structure of the rotor 10 refers to the above-mentioned embodiment. Since the motor 100 adopts all the technical solutions of all the above-mentioned embodiments, it has at least all the beneficial effects brought by the technical solutions of the above-mentioned embodiments, which will not be repeated here one by one.

[0067] In a third aspect, the present application provides a screw drill, comprising a stator 20 and a rotor 10, wherein the stator 20 is formed with a cavity, and the rotor 10 is arranged in the cavity; the rotor 10 comprises a rotor body, and the outer surface of the rotor body is a continuous cycloid spiral surface;

[0068] The rotor body has a first end 111 and a second end 131 which are arranged opposite to each other, and a first segment 11, a middle segment 15 and a second segment 13 which are arranged in sequence along the axis direction of the rotor body;

[0069] The outer diameter of the first section 11 gradually decreases from the first end 111 to the second end 131 , and the outer diameter of the second section 13 gradually decreases from the second end 131 to the first end 111 .

[0070] The inner wall surface of the cavity is formed with a cycloid spiral surface meshing with the rotor 10.

[0071] The screw drill in the embodiment of the present application includes the above-mentioned motor 100, and the specific structure of the motor 100 refers to the above-mentioned embodiment. Since the present screw drill adopts all the technical solutions of all the above-mentioned embodiments, it at least has all the beneficial effects brought by the technical solutions of the above-mentioned embodiments, which will not be described one by one here. In the above-mentioned embodiments, the description of each embodiment has its own emphasis. For the part that is not described in detail in a certain embodiment, please refer to the relevant description of other embodiments.

[0072] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0073] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0074] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be connected, detachably connected, or integrated; it can be mechanically connected or electrically connected; it can be directly connected or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0075] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0076] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms should not be understood as necessarily referring to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification.

[0077] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

[0078] The above is a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed by the present invention, and these modifications or replacements should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A rotor, characterized in that: include: A rotor body, wherein the outer surface of the rotor body is a continuous cycloid spiral surface; The rotor body has a first end and a second end that are arranged opposite to each other, and a first segment body, a middle segment body and a second segment body that are arranged in sequence along the axis direction of the rotor body; The outer diameter of the first section gradually decreases from the first end to the second end, and the outer diameter of the second section gradually decreases from the second end to the first end.

2. The rotor according to claim 1, characterized in that The length of the rotor body is defined as L, the length of the first segment is defined as p*L, satisfying the condition: 0<p<1, and the length of the second segment is defined as (1-p)*L.

3. The rotor according to claim 2, characterized in that The outer diameter of the middle section is defined as a, and the maximum outer diameters of the first section and the second section are both greater than the outer diameter of the middle section by b, and b satisfies the condition 0<b<2mm.

4. The rotor according to claim 3, characterized in that Define any cross section in the first segment as S1, and the distance between S1 and the first end is x, 0≤x≤p*L, satisfying the following conditions:

5. The rotor according to claim 3, characterized in that Define any cross section in the second segment as S2, and the distance between S2 and the second end is y, 0≤y≤(1-p)*L satisfies the condition:

6. The rotor according to claim 3, characterized in that The cycloid spiral surface on the surface of the rotor body can be formed by numerical control machining.

7. A motor, characterized in that: comprising a stator and a rotor as claimed in any one of claims 1 to 6; The stator is formed with a cavity, the rotor is arranged in the cavity, and the inner wall surface of the cavity is formed with a cycloid spiral surface meshing with the rotor.

8. The motor according to claim 7, characterized in that The stator comprises: A housing and a bushing arranged inside the housing, wherein an inner wall surface of the bushing forms a cycloid spiral surface meshing with the rotor.

9. A screw drill, characterized in that: Comprising a motor as claimed in claim 7 or 8.

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