Screw pump metal stator machining device and machining method

Abstract

The invention relates to a screw pump metal stator machining device and method. A lifting mechanism is used for driving a mandrel to do lifting motion in the axial direction of a stator, an expansion sleeve matched with an inner cavity of the stator in shape enables the expansion sleeve in the stator to expand and contract repeatedly, and the stator is soaked in machining liquid in a liquid storage unit; high-precision machining of the stator is achieved by generating discharge pulses between the expansion sleeve and the stator, the method can be used for the stator with higher hardness after heat treatment, the machining precision is high, and the application range is wide.

Description

Technical Field

[0001] This application relates to the technical field of metal processing, and in particular to a processing device and method for a metal stator of a screw pump. Background Art

[0002] In the field of oil extraction, the stator of a screw pump, as a core lifting component, its processing quality directly determines the pump efficiency, wear resistance life and working condition adaptability. Existing screw pump stators are mainly divided into rubber stators and metal stators. Among them, metal stators are usually processed by cutting methods, which have a wide range of applications and can process most workpieces. However, this method has the following defects when processing stators: on the one hand, the stator of a screw pump will bear a large torque during actual use. In order to improve the hardness, heat treatment is required after processing, and heat treatment usually causes deformation of the inner cavity of the stator; since the hardness of the stator after heat treatment becomes higher and conventional cutting tools can no longer be used for cutting, the processing method of the tools has great limitations. On the other hand, the stator of a screw pump is a long-axis workpiece, so a tool bar with a corresponding length needs to be matched. However, if the tool bar is too long, it is easy to produce deviation, resulting in a larger processing error and it is difficult to ensure the accuracy.

[0003] Therefore, we propose a processing device and method for a metal stator of a screw pump. Summary of the Invention

[0004] The applicant of the present invention aims at the above-mentioned disadvantages in the prior art and provides a processing device and method for a metal stator of a screw pump to achieve high-precision processing of the stator.

[0005] The technical solution adopted by the present invention is as follows: A processing device for a metal stator of a screw pump includes a lifting mechanism 1, a mandrel 2, an expansion sleeve 3 and a liquid storage unit 4; the lifting mechanism 1 is fixedly connected to the mandrel 2 and is used to drive the mandrel 2 to move up and down along the axis of the stator 5; the expansion sleeve 3 is arranged in the stator 5 with a gap, and the shape of its outer wall is adapted to the inner cavity of the stator 5; the inside of the expansion sleeve 3 is hollow and is used to cooperate with the mandrel 2 to achieve periodic expansion and contraction, generating discharge pulses between the inner wall of the stator 5; the liquid storage unit 4 is used to accommodate the stator 5 and the processing liquid, and the stator 5 and the expansion sleeve 3 are fixedly arranged in the liquid storage unit 4 in relative insulation.

[0006] Its further technical solution includes that the processing device for a metal stator of a screw pump further includes a positioning mechanism 6, and the positioning mechanism 6 includes a positioning seat 601 and a chuck 602. The positioning seat 601 is fixed in the liquid storage unit 4, and a groove 6011 and a protrusion 6012 matching the shape of the chuck 602 are provided above the positioning seat 601; the chuck 602 is a hollow structure, sleeved outside the protrusion 6012 and abutted against the groove 6011; the lower end surface of the stator 5 abuts against the chuck 602, and the jaws 6021 of the chuck 602 clamp the outer cylindrical surface of the stator 5 to realize the clamping and positioning of the stator 5.

[0007] Its further technical solution includes that m annularly distributed keyways one 301 are formed on the upper end surface of the expansion sleeve 3, and the length direction of the keyway one 301 is the radial direction of the cross-section of the expansion sleeve 3; The positioning mechanism 6 further includes m expansion sleeve positioning members one 603 annularly distributed around the chuck 602. The expansion sleeve positioning member one 603 includes a bracket 6031 and a pressing plate 6032. The bracket 6031 is fixedly arranged above the positioning seat 601. One end of the pressing plate 6032 is fixedly connected to the bracket 6031, and the flange one 60321 at the other end is slidably fitted into the keyway one 301.

[0008] Its further technical solution includes that n annularly distributed keyways two 302 are formed on the lower end surface of the expansion sleeve 3, and the length direction of the keyway two 302 is the radial direction of the cross-section of the expansion sleeve 3; The positioning mechanism 6 further includes an expansion sleeve positioning member two 604. The expansion sleeve positioning member two 604 is a hollow cylindrical structure. A boss 6041 is arranged at its upper end, and n annularly distributed flanges two 6042 are arranged above the boss 6041. The expansion sleeve positioning member two 604 is located inside the chuck 602, and is coaxially and fixedly connected above the protrusion 6012 of the positioning seat 601, below the expansion sleeve 3, and the flange two 6042 is slidably fitted into the keyway two 302.

[0009] Its further technical solution includes that the inner side of the expansion sleeve 3 is a tapered hollow structure with a larger upper part and a smaller lower part, and its outer side is a helical surface structure matching the inner cavity shape of the stator 5 and reduced in proportion. There are several alternately distributed slits 303 on the side wall of the expansion sleeve 3. The slits 303 penetrate the inside and outside of the side wall, and the extension length of the slits 303 is less than the length of the expansion sleeve 3.

[0010] Its further technical solution includes that the main body of the mandrel 2 is a tapered structure with a larger upper part and a smaller lower part, and its taper is the same as that of the tapered hollow structure inside the expansion sleeve 3.

[0011] Its further technical solution includes that the lower end of the mandrel 2 is a cylindrical structure provided with a hollow groove 201; a ring-shaped groove 6011 matching the shape of the cylindrical structure at the lower end of the mandrel 2 is formed on the upper end surface of the protrusion 6012 of the positioning seat 601.

[0012] Its further technical solution includes that the positioning mechanism 6 further includes an elastic member 605. The elastic member 605 is elastically telescopic along the axis direction of the stator 5 and is arranged in the ring-shaped groove 6011.

[0013] Its further technical solution includes that the screw pump metal stator processing device further includes a planar moving mechanism 7. The planar moving mechanism 7 includes two translation components with perpendicular moving directions and both parallel to the ground. Both translation components include a horizontal guide rail 701, a slider 702 located on the horizontal guide rail 701, and a translation driving part 703 for moving the slider 702 on the horizontal guide rail 701.

[0014] A method for processing a screw pump metal stator includes: Fix the stator 5 on the positioning mechanism 6, and immerse the processing fluid in the liquid storage unit 4 in the stator 5; Place the expansion sleeve 3 in the stator 5 and position it through the positioning mechanism 6; After the stator processing device is powered on, the lifting mechanism 1 drives the mandrel 2 to move downward into the expansion sleeve 3. The mandrel 2 moves periodically along the axial direction of the stator 5, causing the expansion sleeve 3 to expand and contract repeatedly. Discharge pulses are generated between the expansion sleeve 3 and the inner wall of the stator 5 to achieve the processing of the stator 5.

[0015] A method for processing a screw pump metal stator includes: Preliminarily process the stator blank by cutting to obtain a stator with an inner cavity formed; Perform heat treatment on the stator with the inner cavity formed; Use the screw pump stator processing device to perform electrical discharge machining on the heat-treated stator.

[0016] The beneficial effects of this application are as follows: This application designs a screw pump metal stator processing device and a corresponding processing method based on the principle of electrical discharge machining. The lifting mechanism drives the mandrel to move periodically along the axial direction of the stator, causing the expansion sleeve in the stator to expand and contract repeatedly. The stator is immersed in the processing fluid in the liquid storage unit, and high-precision processing of the stator is achieved by generating discharge pulses between the expansion sleeve and the stator.

[0017] This application also designs a positioning mechanism, which can accurately position the stator and the expansion sleeve in the liquid storage unit, make the axis of the stator coincide with the axis of the mandrel, and ensure that the expansion sleeve is fixed and will not rotate or move up and down when the mandrel makes periodic axial movement.

[0018] Existing electrical discharge machining methods usually use electrodes with fixed shapes to process workpieces, and it is difficult to process the complex spiral surface of the stator inner cavity. However, this application creatively designs an expansion sleeve and a conical mandrel that match the shape of the stator inner cavity, and combines the two as an electrode through the set processing method, so as to be able to process the stator stably and accurately. Description of the Drawings

[0019] Figure 1 It is a three-dimensional structural schematic diagram of this application.

[0020] Figure 2 This is the front elevation view with a partial cross-sectional view of the present application.

[0021] Figure 3 This is the assembly diagram of the positioning mechanism, stator, and expansion sleeve in the present application.

[0022] Figure 4 This is the cross-sectional assembly diagram of the positioning mechanism, stator, and expansion sleeve in the present application.

[0023] Figure 5 This is the structural diagram of the expansion sleeve in the present application.

[0024] Figure 6 This is the structural diagram of the pressure plate in the present application.

[0025] Figure 7 This is the structural diagram of the second expansion sleeve positioning part in the present application.

[0026] Figure 8 This is the structural diagram of the mandrel in the present application.

[0027] Reference numerals: 1, lifting mechanism; 101, column; 102, vertical guide rail; 103, lifting drive part; 104, lifting block; 2, mandrel; 201, hollow groove; 3, expansion sleeve; 301, keyway one; 302, keyway two; 303, slit; 3031, upper slit; 3032, lower slit; 4, liquid storage tank; 5, stator; 6, positioning mechanism; 601, positioning seat; 602, chuck; 6021, jaw; 603, first expansion sleeve positioning part; 6031, bracket; 6032, pressure plate; 60321, first flange; 604, second expansion sleeve positioning part; 6041, boss; 6042, second flange; 605, elastic part; 7, planar movement mechanism; 701, horizontal guide rail; 702, slider; 703, translation drive part; 8, rotation mechanism; 801, rotation drive part; 802, rotating part; 9, dial indicator; 10, base. Detailed implementation manners

[0028] The following will describe the detailed implementation manners of the present application with reference to the accompanying drawings.

[0029] Embodiment 1

[0030] As Figure 1 、 2As shown in the figure, this embodiment discloses a screw pump metal stator processing device, including a lifting mechanism 1, a mandrel 2, an expansion sleeve 3, and a liquid storage unit 4. Among them, the lifting mechanism 1 is fixedly connected to the mandrel 2 and is used to drive the mandrel 2 to move up and down along the axis of the stator 5. The expansion sleeve 3 is arranged inside the stator 5 with a gap, and the shape of its outer wall is adapted to the inner cavity of the stator 5. The inside of the expansion sleeve 3 is hollow and is used to cooperate with the mandrel 2 to achieve periodic expansion and contraction, generating discharge pulses between it and the inner wall of the stator 5. The liquid storage unit 4 is used to hold the stator 5 and the processing liquid, and the stator 5 and the expansion sleeve 3 are fixedly arranged in the liquid storage unit 4 in relative insulation.

[0031] The stator 1 in this embodiment is specifically a screw pump stator, and the inner cavity of the stator is a multi-start helical surface structure, which can be used for oil extraction. The processing procedures of the stator usually include rough machining, finish machining, and heat treatment. The stator 1 in this embodiment is a stator after heat treatment, which can effectively correct the deformation of the stator caused by heat treatment, thereby ensuring the inner cavity accuracy of the stator.

[0032] In this embodiment, in order to fixedly arrange the stator 5 in the liquid storage unit 4, the screw pump metal stator processing device further includes a positioning mechanism 6. As Figure 3 、 4 shown, the positioning mechanism 6 includes a positioning seat 601 and a chuck 602. The positioning seat 601 is fixed in the liquid storage unit 4, and a groove 6011 and a protrusion 6012 that match the shape of the chuck 602 are provided above the positioning seat 601. The chuck 602 is a hollow structure, sleeved outside the protrusion 6012 and abutted against the groove 6011. The lower end surface of the stator 5 abuts against the chuck 602, and the jaws 6021 of the chuck 602 clamp the outer cylindrical surface of the stator 5 to realize the clamping and positioning of the stator 5.

[0033] In addition to fixing the stator 5, the positioning mechanism 6 in this embodiment can also position the expansion sleeve 3 circumferentially and axially: As Figure 5 shown, m annularly distributed key grooves 301 are provided on the upper end surface of the expansion sleeve 3, and the length direction of the key grooves 301 is the radial direction of the cross-section of the expansion sleeve 3. As Figure 6 shown, the positioning mechanism 6 further includes m expansion sleeve positioning members 603 that are annularly distributed around the chuck 602. The expansion sleeve positioning member 603 includes a bracket 6031 and a pressing plate 6032. The bracket 6031 is fixedly arranged above the positioning seat 601, one end of the pressing plate 6032 is fixedly connected to the bracket 6031, and the flange 60321 at the other end is slidably fitted into the key groove 301.

[0034] During the machining process of the stator 5, when the expansion sleeve 3 is extruded downward by the mandrel 2, it may rotate to a certain extent. When the mandrel 2 is pulled out upward, due to the interference fit between the two, the expansion sleeve 3 also has a tendency to move upward. To avoid such situations, in this embodiment, the pressing plate 6032 presses the expansion sleeve 3 from its upper end, and the groove and the flange are used in cooperation to prevent the expansion sleeve 3 from rotating. In addition, since the expansion sleeve 3 expands and contracts repeatedly during operation, the degree of freedom of the expansion sleeve 3 to move radially needs to be reserved during positioning. In this embodiment, the extension line of the length direction of the keyway 301 passes through the axis of the expansion sleeve 3, so that when the flange 60321 slides in the keyway 301, the thin wall of the expansion sleeve 3 can expand or contract coaxially, further ensuring the machining accuracy.

[0035] In this embodiment, the selected stator 5 is a double-headed stator. Combining the attached Figure 5 It can be seen that arranging 2 keyways 301 is a preferred method. In other embodiments, a three-headed or four-headed stator can also be used, and the number of keyways 301 can be set correspondingly.

[0036] In another embodiment, n annularly distributed keyways 302 are provided on the lower end surface of the expansion sleeve 3, and the length direction of the keyways 302 is the radial direction of the cross-section of the expansion sleeve 3. As Figure 7 shown, the positioning mechanism 6 further includes an expansion sleeve positioning member 604. The expansion sleeve positioning member 604 is a hollow cylindrical structure, and a boss 6041 is provided at its upper end. Above the boss 6041, n annularly distributed flanges 6042 are provided; the expansion sleeve positioning member 604 is located within the chuck 602, and is coaxially fixedly connected above the protrusion 6012 of the positioning seat 601, below the expansion sleeve 3, and the flange 6042 is slidably fitted within the keyway 302.

[0037] Since the expansion sleeve 3 is a long-axis workpiece, if it is only pressed and fixed from the upper end surface of the expansion sleeve 3, the stability may not be guaranteed. In this embodiment, the lower end of the expansion sleeve 3 is positioned by the expansion sleeve positioning member 604, which can enable the expansion sleeve 3 to maintain a high movement accuracy as a whole during operation to machine the stator.

[0038] In addition, both the pressing plate 6032 and the expansion sleeve positioning member 604 are made of insulating materials, and there is a certain gap between the expansion sleeve 3 and the inner cavity of the stator 5. This is because in electrical discharge machining, the expansion sleeve 3 and the mandrel 2 actually act as one electrode together, while the stator 5 acts as the other electrode, and the two electrodes cannot be in direct contact.

[0039] In this embodiment, as Figure 5As shown, the inner side of the expansion sleeve 3 is a conical hollow structure with a larger upper part and a smaller lower part, and its outer side is a spiral surface structure that matches the inner cavity shape of the stator 5 and is reduced in proportion. There are several slits 303 distributed alternately up and down on the side wall of the expansion sleeve 3. The slits 303 penetrate the inside and outside of the side wall, and the extension length of the slits 303 is less than the length of the expansion sleeve 3.

[0040] In one embodiment, the inner cavity of the stator 5 is a conical spiral surface structure, that is, the volume of the inner cavity of the stator 5 increases / decreases along the axial direction. Correspondingly, the outer side of the expansion sleeve 3 is also a corresponding conical spiral surface structure. Preferably, the taper direction of the outer side of the expansion sleeve 3 is the same as that of its inner side. For example, the taper directions of both the inner and outer sides of the expansion sleeve 3 are larger at the upper part and smaller at the lower part.

[0041] Specifically, the slit 303 includes an upper slit 3031 and a lower slit 3032 arranged alternately. The upper slit 3031 extends from the upper end face of the expansion sleeve 3 to the lower end face, and the lower slit 3032 extends from the lower end face of the expansion sleeve 3 to the upper end face. The slit 303 divides the expansion sleeve 3 into several connected slices, and the slices can expand and contract as the mandrel 2 moves up and down.

[0042] In this embodiment, as Figure 8 shown, the main body of the mandrel 2 is a conical structure with a larger upper part and a smaller lower part, and its taper is the same as that of the conical hollow structure on the inner side of the expansion sleeve 3. When the mandrel 2 extends into the expansion sleeve 3, the extrusion force received by the inner wall of the expansion sleeve 3 is evenly distributed, realizing synchronous expansion.

[0043] Optionally, in order to improve the coaxiality between the mandrel 2 and the stator 5 and the stability of the mandrel 2 during movement, the lower end of the mandrel 2 is a cylindrical structure provided with a hollow groove 201; a ring-shaped groove 6011 matching the shape of the cylindrical structure at the lower end of the mandrel 2 is provided on the upper end face of the protrusion 6012 of the positioning seat 601. During the processing, the cylindrical structure at the lower end of the mandrel 2 extends into the ring-shaped groove 6011 of the positioning seat 601, and the hollow groove 201 of the mandrel 2 cooperates with the boss in the ring-shaped groove 6011.

[0044] In this embodiment, the positioning mechanism 6 further includes an elastic member 605. The elastic member 605 is elastically telescopic along the axial direction of the stator 5 and is arranged in the ring-shaped groove 6011. During processing, the cylindrical structure of the mandrel 2 extends into the elastic member 605, and the conical structure of the mandrel 2 abuts against the upper end of the elastic member 605. The elastic member 605 can assist the lifting movement of the mandrel 2.

[0045] In this embodiment, the stator processing device further includes a planar moving mechanism 7. The planar moving mechanism 7 includes two translation components with mutually perpendicular moving directions and both parallel to the ground. Both translation components include a horizontal guide rail 701, a slider 702 located on the horizontal guide rail 701, and a translation driving part 703 for moving the slider 702 on the horizontal guide rail 701.

[0046] Optionally, the screw pump metal stator processing device further includes a base 10. The lifting mechanism 1 includes a column 101, a vertical guide rail 102, a lifting drive unit 103, and a lifting block 104. Among them, the column 101 is fixed on the base 10, the vertical guide rail 102 is fixedly arranged on the column 101 perpendicular to the ground, the lifting drive unit 103 is used to drive the lifting block 104 to slide on the vertical guide rail 102, and the lifting block 104 is connected to the core shaft 2 to drive the core shaft 2 to perform a lifting movement.

[0047] In another embodiment, the screw pump metal stator processing device further includes a rotating mechanism 8. The rotating mechanism 8 is fixedly arranged on the lifting block 104 and includes a rotation drive unit 801 and a rotating part 802. The rotating part 802 is fixedly connected to the core shaft 2, and the rotation drive unit 801 is used to drive the rotating part 802 to rotate.

[0048] Optionally, the screw pump metal stator processing device further includes a dial indicator 9. The dial indicator 9 is fixedly arranged on the lifting block 104 and is used to detect the coaxiality between the core shaft 2 and the stator 5. When the coaxiality between the core shaft 2 and the stator 5 does not meet the set requirements, the control rotating mechanism 8 drives the stator 5 to move in the horizontal direction and is detected by the dial indicator 9 until the coaxiality between the core shaft 2 and the stator 5 meets the standard.

[0049] In order to process the stator 5 through electric discharge machining, the screw pump metal stator processing device of the present application actually further includes a power supply and a control system. The core shaft 2 is connected to the power supply, and the control system is used to control the operation of each drive unit to achieve the corresponding drive function. Both the core shaft 2 and the expansion sleeve 3 are made of conductive materials, such as copper.

[0050] Embodiment 2

[0051] This embodiment discloses a method for processing a screw pump metal stator, including: S110, fixing the stator 5 on the positioning mechanism 6 so that the machining fluid in the liquid storage unit 4 submerges the stator 5; S120, placing the expansion sleeve 3 into the stator 5 and positioning it through the positioning mechanism 6; S130, after the stator processing device is powered on, the lifting mechanism 1 drives the core shaft 2 to move downward into the expansion sleeve 3. The core shaft 2 moves periodically along the axial direction of the stator 5, causing the expansion sleeve 3 to expand and contract repeatedly, generating discharge pulses between the expansion sleeve 3 and the inner wall of the stator 5 to achieve the processing of the stator 5.

[0052] Among them, the machining fluid can be added after the stator 5 is fixed, or can be added after the expansion sleeve 3 is positioned. The machining fluid is an insulating medium and can be kerosene, deionized water, or special electric discharge machining oil. Its main functions are to ionize to form a discharge path, cool, chip removal, and deionize.

[0053] In this embodiment, the processing object is the stator after heat treatment. Since the deformation of the stator is not too large, the electrical discharge machining in this embodiment belongs to finish machining. The corresponding processing parameter ranges are as follows: pulse width 1 μs - 50 μs, pulse interval 10 μs - 100 μs, pulse frequency 10 kHz - 100 kHz, discharge current 0.5 A - 5 A, and open circuit voltage 60 V - 100 V. And because this embodiment is finish machining, in terms of polarity configuration, the mandrel 2 is connected to the positive electrode and the stator 5 is connected to the negative electrode, which can effectively reduce the loss rate of the mandrel 2 and the expansion sleeve 3 and ensure the accuracy of subsequent processing.

[0054] Exemplarily, in one example, the stator material is selected as 38CrMoAl, the pulse width is 20 μs, the pulse interval is 30 μs, the pulse frequency is 20 kHz, the discharge current is 4 A, and the open circuit voltage is 80 V.

[0055] Embodiment 3

[0056] This embodiment discloses a method for machining a metal stator of a screw pump, including: A110, preliminarily machining the stator blank by a cutting method to obtain a stator with an inner cavity formed; A120, performing heat treatment on the stator with the inner cavity formed; A130, performing electrical discharge machining on the heat-treated stator using a screw pump stator machining device.

[0057] Among them, the preliminary machining includes at least one rough machining and may also include semi-finish machining.

[0058] The cutting allowance range after preliminary machining is 0.1 - 0.5 mm, preferably 0.3 mm. When the cutting allowance is greater than 0.5 mm, the stator is semi-finished by a cutting method; when the cutting allowance is less than 0.1 mm, since heat treatment will cause deformation of the inner cavity of the stator, too small a cutting allowance may not be able to compensate for the deformation amount, resulting in a "depression" of the actual inner cavity surface of the stator compared with the theory and making it impossible to remedy through subsequent electrical discharge machining. Therefore, it is determined that the stator in this case is scrapped and no subsequent processing steps are carried out. That is, only the stator with an inner cavity cutting allowance range of 0.1 - 0.5 mm is a stator with an inner cavity formed.

[0059] Among them, the specific steps of performing electrical discharge machining on the heat-treated stator using a screw pump metal stator machining device can refer to S110 - S130 in Embodiment 2.

[0060] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of concise description, not all possible combinations of the technical features in the above embodiments are described. However, as long as the combinations of these technical features do not conflict, they should all be considered as the scope described in this specification.

[0061] The above description is an explanation of the present invention, not a limitation thereof. For the scope defined by the present invention, refer to the claims. Any form of modification may be made within the scope of protection of the present invention.

Claims

1. A metal stator processing device for a screw pump, characterized in that, It includes a lifting mechanism (1), a mandrel (2), an expansion sleeve (3), and a liquid storage unit (4); The lifting mechanism (1) is fixedly connected to the mandrel (2) and is used to drive the mandrel (2) to move up and down along the axis of the stator (5); The expansion sleeve (3) is arranged inside the stator (5) with a gap, and the shape of its outer wall is adapted to the inner cavity of the stator (5); the inside of the expansion sleeve (3) is hollow and is used to cooperate with the mandrel (2) to achieve periodic expansion and contraction, generating discharge pulses between the inner wall of the stator (5); The liquid storage unit (4) is used to accommodate the stator (5) and the processing liquid, and the stator (5) is fixedly arranged in the liquid storage unit (4) relatively insulated from the expansion sleeve (3).

2. The metal stator processing device for a screw pump according to claim 1, characterized in that, The screw pump metal stator processing device further includes a positioning mechanism (6), the positioning mechanism (6) includes a positioning seat (601) and a chuck (602), the positioning seat (601) is fixed in the liquid storage unit (4), and a groove (6011) and a protrusion (6012) matching the shape of the chuck (602) are provided above the positioning seat (601); the chuck (602) is a hollow structure, sleeved outside the protrusion (6012) and abutted against the groove (6011); the lower end surface of the stator (5) abuts against the chuck (602), and the jaws (6021) of the chuck (602) clamp the outer cylindrical surface of the stator (5) to realize the clamping and positioning of the stator (5).

3. The metal stator processing device for a screw pump according to claim 2, wherein m annularly distributed key grooves one (301) are provided on the upper end surface of the expansion sleeve (3), and the length direction of the key grooves one (301) is the radial direction of the cross section of the expansion sleeve (3); The positioning mechanism (6) further includes m expansion sleeve positioning parts one (603) annularly distributed around the chuck (602), the expansion sleeve positioning parts one (603) include a bracket (6031) and a pressing plate (6032), the bracket (6031) is fixedly arranged above the positioning seat (601), one end of the pressing plate (6032) is fixedly connected to the bracket (6031), and the flange one (60321) at the other end is slidably fitted into the key groove one (301).

4. The metal stator processing device for a screw pump according to claim 2, characterized in that, n annularly distributed key grooves two (302) are provided on the lower end surface of the expansion sleeve (3), and the length direction of the key grooves two (302) is the radial direction of the cross section of the expansion sleeve (3); The positioning mechanism (6) further includes an expansion sleeve positioning part two (604), the expansion sleeve positioning part two (604) is a hollow cylindrical structure, a boss (6041) is provided at its upper end, and n annularly distributed flanges two (6042) are provided above the boss (6041); the expansion sleeve positioning part two (604) is located inside the chuck (602), is coaxially fixedly connected above the protrusion (6012) of the positioning seat (601), is located below the expansion sleeve (3), and the flange two (6042) is slidably fitted into the key groove two (302).

5. The metal stator processing device for a screw pump according to claim 1, characterized in that, The inner side of the expansion sleeve (3) is a conical hollow structure with a larger upper part and a smaller lower part, and its outer side is a helical surface structure that matches the shape of the inner cavity of the stator (5) and is reduced in proportion; there are several slits (303) alternately distributed up and down on the side wall of the expansion sleeve (3), the slits (303) penetrate the inside and outside of the side wall, and the extension length of the slits (303) is less than the length of the expansion sleeve (3); the main body of the mandrel (2) is a conical structure with a larger upper part and a smaller lower part, and its taper is the same as that of the conical hollow structure on the inner side of the expansion sleeve (3).

6. The screw pump metal stator processing device according to claim 2, characterized in that, The lower end of the mandrel (2) is a cylindrical structure provided with a hollow groove (201); a ring-shaped groove (6011) matching the shape of the cylindrical structure at the lower end of the mandrel (2) is formed on the upper end surface of the protrusion (6012) of the positioning seat (601).

7. The metal stator processing device for a screw pump according to claim 6, wherein, The positioning mechanism (6) further includes an elastic member (605), and the elastic member (605) is elastically telescopic along the axis direction of the stator (5) and is arranged in the ring-shaped groove (6011).

8. The screw pump metal stator processing device according to claim 1, characterized in that, The metal stator processing device for screw pumps further includes a planar moving mechanism (7), and the planar moving mechanism (7) includes two translation components with mutually perpendicular moving directions and both parallel to the ground. Both translation components include a horizontal guide rail (701), a slider (702) located on the horizontal guide rail (701), and a translation driving part (703) for moving the slider (702) on the horizontal guide rail (701).

9. A processing method for a metal stator of a screw pump, applied to the screw pump metal stator processing device according to any one of claims 1-8, characterized in that, The method for processing a metal stator of a screw pump includes: Fix the stator (5) on the positioning mechanism (6) so that the processing liquid in the liquid storage unit (4) submerges the stator (5). Place the expansion sleeve (3) inside the stator (5) and position it through the positioning mechanism (6). After the metal stator processing device for screw pumps is powered on, the lifting mechanism (1) drives the mandrel (2) to move down into the expansion sleeve (3), and the mandrel (2) moves periodically along the axial direction of the stator (5), causing the expansion sleeve (3) to expand and contract repeatedly, generating discharge pulses between the expansion sleeve (3) and the inner wall of the stator (5) to achieve the processing of the stator (5).

10. A processing method for a metal stator of a screw pump, applied to the screw pump metal stator processing device described in any one of claims 1-8, characterized in that, The method for processing a metal stator of a screw pump includes: Preliminarily process the stator blank by cutting to obtain a stator with a formed inner cavity. Perform heat treatment on the stator with a formed inner cavity. Use the screw pump stator processing device to perform electrical discharge machining on the heat-treated stator.

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