A method and device for assembling outer cylinder and stator of submersible linear motor

Abstract

The invention discloses a method and device for assembling an outer cylinder and a stator of a submersible linear motor, and the assembly method includes: S1: selecting an outer cylinder with a yield strength greater than 450Mpa, making the inner diameter of the outer cylinder larger than the outer diameter of the stator by more than 1mm, and placing the stator in the outer cylinder; S2: heating the outer cylinder to 250-350℃; S3: connecting a cold drawing die to heat and cold draw the outer cylinder, so that a reserved gap exists between the outer cylinder and the stator; the reserved gap is 0.05-1mm; S4: cooling to room temperature after the cold drawing is completed, so that the outer cylinder and the stator have an interference fit; and also discloses a device for assembling an outer cylinder and a stator of a submersible linear motor, including a hydraulic drawing mechanism, a diameter reduction mechanism, a set station and a feeding station. The invention heats and keeps the high yield strength outer cylinder warm before cold drawing, so that the outer cylinder expands and then cold draws, and the temperature of the outer cylinder itself cools to room temperature after cold drawing, thereby eliminating the gap between the motor outer cylinder and the stator, avoiding the vibration generated during the operation of the motor, and reducing the failure rate of the submersible linear motor.

Description

Technical Field

[0001] The invention relates to the field of assembling an outer cylinder and a stator of a submersible linear motor, and more specifically, to a method and a device for assembling an outer cylinder and a stator of a submersible linear motor. Background Art

[0002] In the oil field production process, in order to efficiently and continuously extract the crude oil or well fluid from the well, a reliable motor is required. Submersible linear motors are widely used in oil and gas collection because of their slender and cylindrical shape, which is similar to the structure of oil wells. The outer cylinder of the submersible linear motor is usually a hollow cylindrical structure with openings at both ends. The stator is located inside the outer cylinder and consists of components such as the stator core. The assembly gap between the motor stator and the outer cylinder will cause vibrations during the operation of the linear motor, resulting in a decrease in the life of the motor. Therefore, in order to achieve higher stability and durability, the design of the linear motor pursues an interference fit between the outer cylinder and the stator.

[0003] The existing technology mainly uses cold drawing technology to assemble the motor outer cylinder and the stator, but as the yield strength of the outer cylinder increases, the rebound amount after cold drawing also increases. Experiments show that when the yield strength of the outer cylinder is 300Mpa, the cold drawing reduction amount is 1mm, and the rebound amount is 0.05mm; when the yield strength of the outer cylinder is 500Mpa, the cold drawing reduction amount is 1mm, and the rebound amount is 0.2-0.3mm. In order to meet the load requirements of the oil field, submersible linear motors often use outer cylinders made of materials with a yield strength greater than 450Mpa. Due to the large rebound of this material, it is impossible to achieve interference fitting of an outer cylinder with a high yield strength (yield strength > 450Mpa) and an ultra-long slender linear motor stator after cold drawing.

[0004] The invention patent with application number CN103208887A discloses a method for fixing the stator and the housing of a submersible linear motor, which is characterized in that a seamless steel pipe with an inner diameter larger than the outer diameter of the linear motor stator is first selected as the housing, and the linear motor stator is required to be inserted into the tubular seamless steel pipe housing as a whole; a cold drawing and shrinking die is set, and the inner hole of the cold drawing and shrinking die is composed of a front gradually shrinking guide section and a rear equal diameter sizing section, and then the cold drawing and shrinking die assembled on the cold drawing equipment is used to shrink the diameter as a whole, and the inner diameter of the housing and the outer circle of the linear motor stator are integrally zero-gap fitted. This scheme is only suitable for cold drawing of an outer cylinder with low yield strength (yield strength <450Mpa), and cannot meet the interference fit requirements of an outer cylinder with high yield strength and a stator. For an outer cylinder with high yield strength, as the rebound increases, there will be a gap between the outer cylinder and the stator, and the stator is easily damaged due to the zero-gap fit during cold drawing. Summary of the invention

[0005] In order to solve the problems mentioned in the above background technology, the present invention provides a submersible linear motor outer cylinder and stator assembly device and method to solve the problem in the prior art that the high yield strength motor outer cylinder and stator assembly cannot achieve interference fit.

[0006] The technical solution adopted by the present invention is:

[0007] A method for assembling an outer cylinder and a stator of a submersible linear motor, the method comprising the following assembly steps:

[0008] S1: Select an outer cylinder with a yield strength greater than 450Mpa, make the inner diameter of the outer cylinder greater than the outer diameter of the stator by more than 1mm, and place the stator in the outer cylinder;

[0009] S2: Heat the outer cylinder to 250-350°C;

[0010] S3: Connect the cold drawing die to heat and cold draw the outer cylinder, so that there is a reserved gap between the outer cylinder and the stator; the reserved gap is 0.05-1mm;

[0011] S4: After the cold drawing is completed, it is cooled to room temperature to make the outer tube and the stator have an interference fit.

[0012] Furthermore, the heating device is an induction heating device.

[0013] Furthermore, during the cold drawing process, the direction of the drawing force is consistent with the direction of the axis of the outer cylinder.

[0014] Furthermore, after the step S3, the step also includes measuring the dimensions and inspecting the appearance of the outer cylinder and the stator after cooling to room temperature.

[0015] A submersible linear motor outer cylinder and stator assembly device, comprising a hydraulic drawing mechanism, a diameter reduction mechanism, a set-in position and a feeding position; the hydraulic drawing mechanism comprises a hydraulic device, a support device, a blanking position and a drawing connection device, and the hydraulic device is installed on the support device; the blanking position is arranged in front of the diameter reduction mechanism and is fixedly connected to the support device; the drawing connection device is connected to the hydraulic piston rod of the hydraulic device; the diameter reduction mechanism is arranged at the connection between the hydraulic drawing mechanism and the set-in position, and comprises a cold drawing die and an induction heating device; the feeding position comprises an automatic feeding mechanism; the set-in position is fixedly connected to the diameter reduction mechanism and is provided with a lifting system.

[0016] Furthermore, the supporting device includes a base, a retaining frame fixedly connected to the base, and a cylinder supporting frame mounted on the retaining frame.

[0017] Furthermore, the pulling connection device includes an outer tube pulling head, an intermediate connecting rod threadedly connected to the outer tube pulling head, a pulling connection head threadedly connected to the other end of the intermediate connecting rod, and a hydraulic piston rod connection head; the hydraulic piston rod connection head is connected to the pulling connection head through a pin.

[0018] Furthermore, the automatic feeding mechanism includes a feeding base, a lifting mechanism arranged on the feeding base, and a V-shaped support seat connected to the lifting mechanism; the lifting mechanism includes a driving motor, a lifting connecting shaft connected to the driving motor, and the lifting connecting shaft is connected to the V-shaped support seat through a coupling.

[0019] Furthermore, the surface of the V-shaped support seat in contact with the stator is provided with a pulley

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] The present invention heats and keeps the high-yield strength outer cylinder warm before cold drawing, so that the outer cylinder expands and then is cold drawn. After cold drawing, the temperature of the outer cylinder itself cools to room temperature, and physical shrinkage causes interference fit after cold drawing, thereby eliminating the gap between the motor outer cylinder and the stator, avoiding vibration generated during the operation of the motor, thereby reducing the failure rate of the submersible linear motor and increasing the service life of the submersible linear motor. At the same time, the assembly device of the present invention can adapt to the assembly of the outer cylinder of the submersible linear motor with an extra-long length and meet the coaxiality requirements of the assembly. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a structural schematic diagram of an assembly device for an outer cylinder and a stator of a submersible linear motor;

[0023] Figure 2 It is a schematic diagram of the structure of a hydraulic device;

[0024] Figure 3 It is a structural schematic diagram of a pull-out connection device;

[0025] Figure 4 It is a structural schematic diagram of an automatic feeding mechanism of a feeding station;

[0026] Figure 5 It is a structural schematic diagram of a diameter reduction mechanism.

[0027] Among them: 1. outer cylinder; 2. stator; 3. hydraulic drawing mechanism; 301. cylinder support frame; 302. retaining frame; 303. blanking platform; 304. base; 305 linear guide rail; 306. sliding seat; 307. washer; 308. connecting bolt; 309. hydraulic piston rod connector; 310. intermediate connecting rod; 311. outer cylinder drawing head; 312. latch; 313. drawing connector; 4. reducing mechanism; 401. cold drawing die; 402. induction heating device; 5. set platform; 6. feeding platform; 601. feeding base; 602. lifting mechanism; 603. lifting connecting shaft; 604. driving motor; 605. V-shaped support seat; 606. coupling. DETAILED DESCRIPTION

[0028] In order to clearly illustrate the technical features of this solution, the present invention is described in detail below through specific implementation methods and in combination with the accompanying drawings. In the following description, many specific details are described to facilitate a full understanding of the present application, but the present application can also be implemented in other ways different from those described herein, so the protection scope of the present application is not limited by the specific embodiments disclosed below. In addition, in the description of the present application, it should be understood that the orientation or position relationship indicated by the terms "center", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "axial", "radial", "circumferential", etc. is based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, the features defined as "first" and "second" can explicitly or implicitly include one or more of the features. In the description of this application, "multiple" means two or more, unless otherwise clearly specified and specifically defined. In this application, unless otherwise clearly specified and defined, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral body; it can be a mechanical connection, an electrical connection, or a communication; 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 this application can be understood according to the specific circumstances. In this application, unless otherwise clearly specified and defined, the first feature "on" or "under" the second feature can be the first and second features directly contacting, or the first and second features indirectly contacting through an intermediate medium. In the description of this specification, the description of the reference terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" 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 this application. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0029] Example 1

[0030] See also Figures 1 to 5 , an embodiment provided by the present invention:

[0031] A method for assembling an outer cylinder and a stator of a submersible linear motor comprises the following steps:

[0032] S1: Select an outer cylinder with a yield strength greater than 450Mpa, make the inner diameter of the outer cylinder greater than the outer diameter of the stator by more than 1mm, and place the stator in the outer cylinder;

[0033] S2: Heat the outer cylinder to 250-350°C;

[0034] S3: Connect the cold drawing die to heat and cold draw the outer cylinder, so that there is a reserved gap between the outer cylinder and the stator; the reserved gap is 0.05;

[0035] S4: After the cold drawing is completed, it is cooled to room temperature to make the outer tube and the stator have an interference fit.

[0036] During the cold drawing process, the direction of the drawing force must be controlled to be consistent with the axis direction of the outer cylinder, so that the material can undergo uniform plastic deformation along the axis direction, thereby avoiding internal stress concentration and defects caused by uneven deformation.

[0037] After cooling, the outer cylinder and stator need to be measured for size and inspected for appearance to check whether there is any damage.

[0038] This method heats the high yield strength outer cylinder before cold drawing, controls the heating temperature within 250℃~350℃, and then shrinks the diameter through the cold drawing die, and reserves a gap of 0.05mm. After naturally cooling to room temperature, the thermal expansion size of the outer cylinder changes by 0.6~1mm, causing interference after cold drawing. After cold drawing, the gap is controlled at 0.05mm. After the outer cylinder shrinks, combined with the rebound amount, the interference fit between the outer cylinder and the stator can be controlled just right without damaging the stator.

[0039] Example 2

[0040] See also Figures 1 to 5 , an embodiment provided by the present invention:

[0041] A submersible linear motor outer cylinder and stator assembly device, comprising a hydraulic drawing mechanism 3, a diameter reduction mechanism 4, a set position 5 and a feeding position 6; the hydraulic drawing mechanism 3 comprises a hydraulic device, a support device, a blanking position 303 and a drawing connection device, and the hydraulic device is installed on the support device; the blanking position 303 is arranged in front of the diameter reduction mechanism 4 and is fixedly connected to the support device; the drawing connection device is connected to the hydraulic piston rod of the hydraulic device; the diameter reduction mechanism 4 is arranged at the connection between the hydraulic drawing mechanism 3 and the set position 5, and comprises a cold drawing die 401 and an induction heating device 402; the feeding position comprises an automatic feeding mechanism, which can conveniently feed the stator core into the outer cylinder; the set position 5 is fixedly connected to the diameter reduction mechanism 4 and is provided with a lifting system.

[0042] like Figure 2 As shown, the hydraulic device provides a set drawing pressure for the workpiece when the tube is bundled, and the maximum pulling force is 100 tons. The supporting device includes a base 304, a retaining frame 302 fixedly connected to the base, and a cylinder support frame 301 mounted on the retaining frame 302; the retaining frame 302 is connected to the base 304 by connecting bolts 308; the blanking platform 303 is used to support the workpiece, and a linear guide rail 305 is mounted on the blanking platform 303 to assist the movement of the workpiece; a sliding seat 306 is provided at the rear end of the blanking platform 303, which is slidably connected to the cylinder, and a shim 307 is provided at the bottom of the sliding seat 306 to reduce the influence of machine tool vibration; the blanking platform 303 is also provided with a lifting mechanism, and the lifting mechanism can continue to rise a distance upward to facilitate the lifting of the workpiece.

[0043] like Figure 3 As shown, the drawing connection device connects the hydraulic device and the outer cylinder, including an outer cylinder drawing head 311, an intermediate connecting rod 310 threadedly connected to the outer cylinder drawing head 311, a drawing connection head 313 threadedly connected to the other end of the intermediate connecting rod, and a hydraulic piston rod connection head 309; the hydraulic piston rod connection head 309 is connected to the drawing connection head 311 through a pin 312; the outer cylinder drawing head 311 is provided with an external thread, which is threadedly connected to the internal thread of the outer cylinder, and the outer cylinder drawing head 311 and the hydraulic piston rod connection head 309 need to be adjusted to be concentric before drawing, and then the drawing operation is performed.

[0044] like Figure 4 As shown, the automatic feeding mechanism includes a feeding base 601, a lifting mechanism 602 arranged on the feeding base 601, and a V-shaped support seat 605 connected to the lifting mechanism 602; the lifting mechanism includes a driving motor 604, and a lifting connecting shaft 603 connected to the driving motor. The lifting connecting shaft 603 is connected to the V-shaped support seat through a coupling 606, which can control the lifting and lowering of the stator 2 and feed it into the outer cylinder 1. The surface of the V-shaped support seat 605 that contacts the stator is provided with a pulley to facilitate the movement of the outer cylinder on the V-shaped support seat 605.

[0045] like Figure 5 As shown, the shrinking mechanism 4 includes a cold drawing die 401 and an induction heating device 402. The cold drawing die 401 is a die steel with high strength, high hardness and high wear resistance to reduce deformation during the drawing process and improve the drawing accuracy. The induction heating device 402 heats the outer cylinder 1.

[0046] The device of this embodiment is used to assemble a high-yield outer cylinder with a stator. The outer cylinder has a diameter of 143 mm and a length of 15 m. After the outer cylinder is cold-drawn, the temperature of the outer cylinder decreases and radial shrinkage occurs by 0.62 mm, achieving an interference fit between the outer cylinder and the stator, thereby improving the sealing performance of the motor.

[0047] Example 3

[0048] See also Figures 1 to 5 , an embodiment provided by the present invention:

[0049] A method for assembling an outer cylinder and a stator of a submersible linear motor comprises the following steps:

[0050] S1: Select an outer cylinder with a yield strength greater than 450Mpa, make the inner diameter of the outer cylinder greater than the outer diameter of the stator by more than 1mm, and place the stator in the outer cylinder;

[0051] S2: Heat the outer cylinder to 250-350°C;

[0052] S3: Connect the cold drawing die to heat and cold draw the outer cylinder, so that there is a reserved gap between the outer cylinder and the stator; the reserved gap is 1mm;

[0053] S4: After the cold drawing is completed, it is cooled to room temperature to make the outer tube and the stator have an interference fit.

[0054] Furthermore, in the step S2, lubricant is added to the contact surface between the cold drawing device and the outer cylinder to reduce equipment loss and friction during drawing.

[0055] After cooling, the outer cylinder and stator need to be measured for size and inspected for appearance to check whether there is any damage.

[0056] A submersible linear motor outer cylinder and stator assembly device, comprising a hydraulic drawing mechanism 3, a diameter reduction mechanism 4, a set position 5 and a feeding position 6; the hydraulic drawing mechanism 3 comprises a hydraulic device, a support device, a blanking position 303 and a drawing connection device, and the hydraulic device is installed on the support device; the blanking position 303 is arranged in front of the diameter reduction mechanism 4 and is fixedly connected to the support device; the drawing connection device is connected to the hydraulic piston rod of the hydraulic device; the diameter reduction mechanism 4 is arranged at the connection between the hydraulic drawing mechanism 3 and the set position 5, and comprises a cold drawing die 401 and an induction heating device 402; the feeding position comprises an automatic feeding mechanism, which can conveniently feed the stator core into the outer cylinder; the set position 5 is fixedly connected to the diameter reduction mechanism 4 and is provided with a lifting system.

[0057] like Figure 2As shown, the hydraulic device provides a set drawing pressure for the workpiece when the tube is bundled, and the maximum pulling force is 100 tons. The supporting device includes a base 304, a retaining frame 302 fixedly connected to the base, and a cylinder support frame 301 mounted on the retaining frame 302; the retaining frame 302 is connected to the base 304 by connecting bolts 308; the blanking platform 303 is used to support the workpiece, and a linear guide rail 305 is mounted on the blanking platform 303 to assist the movement of the workpiece; a sliding seat 306 is provided at the rear end of the blanking platform 303, which is slidably connected to the cylinder, and a shim 307 is provided at the bottom of the sliding seat 306 to reduce the influence of machine tool vibration; the blanking platform 303 is also provided with a lifting mechanism, and the lifting mechanism can continue to rise a distance upward to facilitate the lifting of the workpiece.

[0058] like Figure 3 As shown, the drawing connection device connects the hydraulic device and the outer cylinder, including an outer cylinder drawing head 311, an intermediate connecting rod 310 threadedly connected to the outer cylinder drawing head 311, a drawing connection head 313 threadedly connected to the other end of the intermediate connecting rod, and a hydraulic piston rod connection head 309; the hydraulic piston rod connection head 309 is connected to the drawing connection head 311 through a pin 312; the outer cylinder drawing head 311 is provided with an external thread, which is threadedly connected to the internal thread of the outer cylinder, and the outer cylinder drawing head 311 and the hydraulic piston rod connection head 309 need to be adjusted to be concentric before drawing, and then the drawing operation is performed.

[0059] like Figure 4 As shown, the automatic feeding mechanism includes a feeding base 601, a lifting mechanism 602 arranged on the feeding base 601, and a V-shaped support seat 605 connected to the lifting mechanism 602; the lifting mechanism includes a driving motor 604, and a lifting connecting shaft 603 connected to the driving motor. The lifting connecting shaft 603 is connected to the V-shaped support seat through a coupling 606, which can control the lifting and lowering of the stator 2 and feed it into the outer cylinder 1.

[0060] like Figure 5 As shown, the shrinking mechanism 4 includes a cold drawing die 401 and an induction heating device 402. The cold drawing die 401 is a die steel with high strength, high hardness and high wear resistance to reduce deformation during the drawing process and improve the drawing accuracy. The induction heating device 402 heats the outer cylinder 1.

[0061] During the drawing operation, molybdenum disulfide lubricant is added to the contact surface between the cold drawing die 401 and the outer tube 1 for lubrication, thereby reducing die loss and friction, reducing tube deformation, and extending the service life of the equipment.

[0062] By using the device and method of this embodiment, an induction heating device is used before cold drawing of the high yield strength outer cylinder. The outer cylinder has a diameter of 123 mm and a length of 15 m. After the outer cylinder is cold drawn, the temperature of the outer cylinder decreases and radial shrinkage occurs by 0.63 mm, achieving an interference fit between the outer cylinder and the stator, thereby improving the sealing performance of the motor.

[0063] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A method for assembling an outer cylinder and a stator of a submersible linear motor, characterized in that: The method comprises the following assembly steps: S1: Select an outer cylinder with a yield strength greater than 450Mpa, make the inner diameter of the outer cylinder greater than the outer diameter of the stator by more than 1mm, and place the stator in the outer cylinder; S2: Heat the outer cylinder to 250-350°C; S3: Connect the cold drawing die to heat and cold draw the outer cylinder, so that there is a reserved gap between the outer cylinder and the stator; the reserved gap is 0.05-1mm; S4: After the cold drawing is completed, it is cooled to room temperature to make the outer tube and the stator have an interference fit.

2. A method for assembling an outer cylinder and a stator of a submersible linear motor according to claim 1, characterized in that: In the step S2, lubricant is added to the contact surface between the cold drawing device and the outer cylinder for lubrication.

3. The method for assembling the outer cylinder and stator of a submersible linear motor according to claim 1, characterized in that: The heating device is an induction heating device.

4. A method for assembling an outer cylinder and a stator of a submersible linear motor according to claim 1, characterized in that: During the cold drawing process, the direction of the drawing force is consistent with the axis direction of the outer cylinder.

5. The method for assembling the outer cylinder and stator of a submersible linear motor according to claim 1, characterized in that: After the step S3, the process also includes measuring the dimensions and inspecting the appearance of the outer cylinder and the stator after they have been cooled to room temperature.

6. A submersible linear motor outer cylinder and stator assembly device, characterized in that: It includes a hydraulic drawing mechanism, a diameter reduction mechanism, a set-up table and a feeding table; the hydraulic drawing mechanism includes a hydraulic device, a supporting device, a blanking table and a drawing connection device, and the hydraulic device is installed on the supporting device; the blanking table is arranged in front of the diameter reduction mechanism and is fixedly connected to the supporting device; the drawing connection device is connected to the hydraulic piston rod of the hydraulic device; the diameter reduction mechanism is arranged at the connection between the hydraulic drawing mechanism and the set-up table, and includes a cold drawing die and an induction heating device; the feeding table includes an automatic feeding mechanism; the set-up table is fixedly connected to the diameter reduction mechanism and is provided with a lifting system.

7. The outer cylinder and stator assembly device of a submersible linear motor according to claim 6, characterized in that: The supporting device comprises a base, a retaining frame fixedly connected to the base, and an oil cylinder supporting frame mounted on the retaining frame.

8. The outer cylinder and stator assembly device of a submersible linear motor according to claim 6, characterized in that: The drawing connection device includes an outer tube drawing head, an intermediate connecting rod threadedly connected to the outer tube drawing head, a drawing connection head threadedly connected to the other end of the intermediate connecting rod, and a hydraulic piston rod connection head; the hydraulic piston rod connection head is connected to the drawing connection head through a pin.

9. The outer cylinder and stator assembly device of a submersible linear motor according to claim 6, characterized in that: A pulley is provided on the surface of the V-shaped support seat in contact with the stator, and is characterized in that: the automatic feeding mechanism includes a feeding base, a lifting mechanism arranged on the feeding base, and a V-shaped support seat connected to the lifting mechanism; the lifting mechanism includes a driving motor, a lifting connecting shaft connected to the driving motor, and the lifting connecting shaft is connected to the V-shaped support seat through a coupling.

10. The outer cylinder and stator assembly device of a submersible linear motor according to claim 9, characterized in that: The surface of the V-shaped support seat in contact with the stator is provided with a pulley.

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