Semi-direct drive permanent magnet synchronous motor for pumping unit

Abstract

A semi-direct drive permanent magnet synchronous motor for a pumping unit, the semi-direct drive permanent magnet synchronous motor comprising a housing, and a stator and a rotor arranged in the housing. The rotor comprises a rotor core, magnetic steel slots arranged on the rotor core, and magnetic steel arranged in the magnetic steel slots. A magnetic isolation bridge is arranged on the side of each magnetic steel slot close to an outer edge of the rotor core, and a hollow magnetic isolation part is arranged on the side of the magnetic steel slot close to the middle of the rotor core. A magnetic pole is arranged between each two adjacent magnetic steel slots, and the sides of the two pieces of magnetic steel located on two sides of the magnetic pole and facing the magnetic pole have a same polarity. Compared with the prior art, the present invention has the following advantages: each hollow magnetic isolation part is arranged on the side of the magnetic steel close to the middle of the rotor core, which effectively suppresses the flux leakage of the magnetic steel while achieving weight reduction of the rotor core and improving the energy conversion efficiency of the motor. The provision of a first reinforcing annular plate and a second reinforcing annular plate improves the mechanical strength of the rotor and compensates for the impairment to strength caused by the hollow magnetic isolation parts; moreover, the magnetic steel is lowered down to be covered therein, so that harm caused by the magnetic steel falling off is eliminated.

Description

A semi-direct drive permanent magnet synchronous motor for oil pumping units Technical Field

[0001] The present invention relates to the field of electric motors, and in particular to a semi-direct drive permanent magnet synchronous motor for an oil pumping unit. Background Art

[0002] A magnetic isolation bridge is a magnetic isolation measure used in permanent magnet motors to prevent excessive magnetic flux leakage from the permanent magnets, which can lead to low magnet utilization. The magnetic isolation bridge acts like a dam, effectively guiding magnetic flux lines through the permanent magnets, thereby improving motor efficiency.

[0003] Low-speed, high-torque motors, such as those used in oilfield pumping units, generally utilize low-speed, high-torque direct-drive or semi-direct-drive motors with relatively low speeds and multiple stages. For large motors, higher efficiency also means lower heat generation, and therefore greater losses during operation. The preferred operating condition is one of high efficiency. For low-speed, high-torque motors, copper loss is a major loss factor. The main magnetic flux in a permanent magnet motor is established by permanent magnets. If the utilization rate of these magnets is low, the overall armature reaction will be affected, requiring a higher current. This results in greater copper loss, increased motor heating, and reduced efficiency. Therefore, magnetic isolation of the rotor poles to reduce magnetic leakage is essential for energy conservation and efficiency improvement.

[0004] Secondly, traditional stator coils are manually laid out using slotted insulation paper within the stator slots. After winding, the excess slot paper is shaved flat, then the two sides are wrapped into the slots. Finally, slot wedges are inserted into the slots to hold down the conductors and prevent them from leaking out. This has the following disadvantages: 1. The slot paper is a flat insulating paper cut to a specific size. After curling, it doesn't conform to the slot shape. Especially for trapezoidal stator slots, there are large gaps in the corners, preventing them from being laid out. This affects the utilization of the stator slot area, resulting in a low slot fill rate, low motor power density, and poor heat dissipation during operation. 2. The slot paper is a uniformly thick insulating paper. The thickness of the slot paper used in small motors is generally 0.18-0.35mm. During the offline process, the use of auxiliary tools can easily cause unexpected damage to the slot paper. In addition, since the slot paper is smooth and flat, it is easy to deflect and move axially during the offline process, resulting in uneven effective protection lengths at the protruding parts of the two ends. In severe cases, its dielectric performance cannot meet the standard. After the offline process is completed, the electromagnetic wires are discrete and compacted in the slot, and the slot paper cannot axially adjust the protruding lengths on both sides. In this case, it is generally dismantled or reworked.

[0005] The stator of a semi-direct-drive permanent magnet synchronous motor for an oil pumping unit requires rigorous shaping and flattening of both ends of the stator winding due to axial space limitations within the product's exterior. This thinness of the insulating paper within the slots makes the corners susceptible to damage during the shaping process, causing leakage and failing the withstand voltage test and insulation resistance standards. Even if no damage is visible to the naked eye or the withstand voltage test exhibits no flashover, and the leakage current is within acceptable limits, the structure and process inherently dictate that the slot insulation within the stator assembly will harbor numerous small areas of damage and stress concentration. During use, the temperature rise generated by the high load of the motor can exacerbate aging of the insulating paper or fatigue failure in stress-concentrated areas, posing a significant quality risk.

[0006] Furthermore, the gearbox of a traditional beam pumping unit is connected to an induction motor via a belt. During production, the gearbox requires regular lubrication changes, which can lead to environmental pollution problems such as oil seepage and leakage over time. Furthermore, the motor belt is prone to slippage and wear, typically requiring replacement every one or two months. Over time, as wear increases, the pumping unit's transmission efficiency decreases.

[0007] In the past two years, to tap into the potential for energy conservation and consumption reduction and effectively reduce the unit fluid consumption of pumping wells, a new energy-saving technology has been developed. Installing a permanent magnet semi-direct-drive synchronous motor on the pumping unit eliminates the belt drive system and directly drives the pumping unit's input shaft. Through field testing, energy-saving effect comparisons, motor selection calculations, and noise testing, this technology has achieved an average active power saving rate of 16.05% and a 2.96% increase in system efficiency, achieving significant energy-saving and environmental benefits.

[0008] Currently, this type of permanent magnet semi-direct-drive synchronous motor is relatively large, typically with an oblate structure of approximately 0.5-2 meters in diameter. The outer shell is a split, welded structure, making it difficult to precisely control the inner diameter of the outer shell. During stator installation, two unfavorable conditions arise: First, a large gap exists between the stator and the outer shell after installation, resulting in poor motor stability; second, the stator and outer shell have an interference fit, requiring violent installation such as pounding or hammering to insert the stator into the outer shell. This violent press-fitting can easily lead to quality defects, structurally concentrating stress on related components and posing a risk of fatigue failure under long-term, high-load operation. Furthermore, excessive interference fit can distort the local performance of the stator core, increasing the motor's AC and stray losses. In either case, the stator is ultimately welded to the outer shell, making subsequent maintenance of the motor difficult and costly. Summary of the Invention

[0009] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a semi-direct drive permanent magnet synchronous motor for an oil pumping unit.

[0010] The main technical solution adopted by the semi-direct drive permanent magnet synchronous motor for the oil pumping unit provided in accordance with the present invention is: it includes a casing, a stator and a rotor arranged in the casing, the rotor includes a rotor core, a magnetic steel slot arranged on the rotor core and a magnet arranged in the magnetic steel slot, and is characterized in that a magnetic isolation bridge is provided on the side of the magnetic steel slot close to the outer edge of the rotor core, a hollow magnetic isolation portion is provided on the side of the magnetic steel slot close to the middle of the rotor core, a magnetic pole is provided between two adjacent magnetic steel slots, and the two magnets located on both sides of the magnetic pole have the same polarity as the side opposite to the magnetic pole.

[0011] The semi-direct drive permanent magnet synchronous motor for the oil pumping unit provided by the present invention also adopts the following auxiliary technical solutions:

[0012] Preferably, the rotor core includes a silicon steel sheet annular portion and a rotor support fixed to the middle of the silicon steel sheet annular portion, and the magnets and magnetic poles are both provided on the silicon steel sheet annular portion.

[0013] Preferably, the annular portion of the silicon steel sheet includes a magnetic steel positioning ring and a bracket fixing ring arranged on the inner side of the magnetic steel positioning ring. A plurality of connecting beams are evenly arranged between the magnetic steel positioning ring and the bracket fixing ring, and the hollow magnetic isolation portion is formed between two adjacent connecting beams.

[0014] Preferably, a top block is provided at the position of the hollow magnetic isolation portion opposite to the magnetic steel slot, one end of the top block is connected to the bracket fixing ring, and the other end of the top block is against the inner side surface of the magnetic steel. The contact area between the top block and the magnetic steel is smaller than the area of ​​the inner side surface of the magnetic steel, and the hollow magnetic isolation portion is connected to the magnetic steel slot.

[0015] Preferably, a positioning flat key is provided on the outer side wall of the rotor bracket, and a rotor keyway is provided on the inner side wall of the silicon steel sheet annular portion; a positioning ring plate is also included, and a limiting ring plate is provided at one end of the rotor bracket, and the outer diameters of the limiting ring plate and the positioning ring plate are both larger than the inner diameter of the silicon steel sheet annular portion; the other end of the rotor bracket is inserted into the silicon steel sheet annular portion, the positioning flat key is inserted into the rotor keyway, the limiting ring plate is abutted against one side of the silicon steel sheet annular portion, and the positioning ring plate is abutted against the other side of the silicon steel sheet annular portion and is connected to the rotor bracket through a first locking member.

[0016] Preferably, a first reinforcing annular plate and a second reinforcing annular plate are provided on both sides of the rotor core, and also includes a second locking piece, which passes through the first reinforcing annular plate, the rotor core and the first reinforcing annular plate in sequence and locks them together, and the first reinforcing annular plate and the first reinforcing annular plate cover both sides of the magnetic steel slot.

[0017] Preferably, the first reinforcing annular plate and the second reinforcing annular plate are both provided with locking through holes, and the second locking member passes through the locking through holes and the hollow magnetic isolation portion for fixation.

[0018] Preferably, it also includes a reinforcing positioning piece, the first reinforcing annular plate and the second reinforcing annular plate are both provided with reinforcing through holes, and at least some of the sides of the magnetic poles are provided with reinforcing positioning holes, and the reinforcing positioning piece passes through the reinforcing through holes and the reinforcing positioning holes in turn to strengthen and fix the first reinforcing annular plate and the second reinforcing annular plate to the magnetic poles.

[0019] Preferably, the magnetic pole has a fan-shaped structure.

[0020] Preferably, the annular portion of the silicon steel sheet is formed by stacking a plurality of integrally formed silicon steel sheets.

[0021] Preferably, the housing includes a middle housing, a front cover and a rear cover provided at both ends of the middle housing;

[0022] The stator includes a stator core, on which a plurality of stator teeth are evenly arranged, with slots formed between adjacent stator teeth, and coils wound around the stator teeth, with the coils passing through the slots during the winding process;

[0023] The radial cross-section of the tooth slot is trapezoidal, and the free ends of the stator teeth extend to the tooth slots on both sides to form pole shoes. A tooth slot insulation component is provided in the tooth slot, and the tooth slot insulation component includes a slot insulation frame, insulation cover paper and slot wedge. The outer wall of the slot insulation frame fits with the inner wall of the tooth slot, the slot wedge is located at the mouth of the tooth slot and presses the coil, the two ends of the slot wedge are limited by the pole shoes, and the insulation cover paper is located between the coil and the slot wedge to insulate and isolate the two.

[0024] Preferably, the slot insulation skeleton includes an insulation bottom wall and insulation side walls provided on both sides of the insulation bottom wall, the insulation bottom wall abuts against the bottom wall of the tooth slot, and the insulation side walls abut against the side walls of the tooth slot.

[0025] Preferably, one end of the insulating side wall is connected to the insulating bottom wall, and the other end abuts against the root of the pole shoe.

[0026] Preferably, both axial ends of the slot insulation frame extend out of the tooth slots and form limiting ribs, which are clamped on the axial edges of the tooth slots.

[0027] Preferably, the limiting ribs are provided on the insulating bottom wall and the insulating side walls, and a notch is formed in the middle of the limiting rib located on the insulating bottom wall.

[0028] Preferably, the insulating cover paper includes an insulating top and insulating side portions provided at both ends of the insulating top, the insulating top contacts the slot wedge, and the insulating side portions are inserted into the slot insulating frame and overlap with the inner wall of the slot insulating frame.

[0029] Preferably, both axial ends of the insulating cover paper and the slot wedge extend out of the tooth groove.

[0030] Preferably, both the front end cover and the rear end cover are provided with shaft holes, and a drive shaft hole is provided in the middle of the rotor, and the drive shaft hole is opposite to the shaft holes on the front end cover and the rear end cover.

[0031] Preferably, the middle shell and the stator are in transition fit, a limiting ring is provided on the inner wall of the middle shell along the circumferential direction, one end of the stator rests on the limiting ring and is fixedly connected to the limiting ring via a locking member.

[0032] Preferably, a pressure plate is provided at the other end of the stator, and the locking member passes through the pressure plate and the stator in sequence and is fixed to the limiting ring.

[0033] Preferably, the pressure plate is an arc-shaped structure, and there are multiple pressure plates that are evenly attached to the edge of the stator, with a gap formed between two adjacent pressure plates.

[0034] Preferably, a flat key is provided on the inner wall of the middle shell, a stator key slot is provided on the outer wall of the stator, and the flat key and the stator key slot are limitedly matched.

[0035] Preferably, a keyway is provided on the inner wall of the middle shell, the bottom end of the flat key is inserted into the keyway and fixed to the middle shell, and the top end of the flat key is exposed and protrudes from the keyway.

[0036] Preferably, the flat key is provided on the inner wall of the middle shell near the bottom, a water accumulation groove is provided at the position corresponding to the flat key on the limiting ring, a drainage hole is provided at the position of the front cover or the rear cover opposite to the water accumulation groove, and a removable blocking bolt is provided in the drainage hole.

[0037] Preferably, the middle shell is an integrally formed structure.

[0038] Preferably, the middle shell and the limiting ring are an integrally formed structure.

[0039] Preferably, the middle shell is a structure that penetrates from left to right.

[0040] Preferably, the outer shell further comprises a mounting seat, and the bottom of the middle shell is provided with mounting feet, which are fixedly connected to the mounting seat.

[0041] The semi-direct drive permanent magnet synchronous motor for oil pumping units provided by the present invention has the following advantages compared with the prior art: First, the present invention arranges a magnetic isolation bridge on the outer edge of the rotor core, and arranges a hollow magnetic isolation part on the side of the magnet close to the middle of the rotor core, which effectively suppresses the magnetic leakage of the magnet. In particular, the arrangement of the hollow magnetic isolation part not only isolates the magnet but also reduces the weight of the rotor core, which helps to improve the energy conversion efficiency of the motor; it is beneficial to reduce the copper loss of the motor, reduce the iron loss of the rotor and other stray losses; at the same time, for large motors, because their power and load are relatively large, their heat dissipation performance is poorer than that of small motors. Therefore, the above-mentioned magnetic isolation measures can reduce the thermal load of the motor during operation, improve the service life and working stability of the motor, and It has very important practical significance for the efficient operation of large motors. Finally, the two magnets located on both sides of the magnetic pole have the same polarity on the side opposite to the magnetic pole. This structure can superimpose the magnetic flux of one magnetic pole, so that the rotor magnetomotive force of each magnetic pole is greatly enhanced, further improving the air gap magnetic density, thereby increasing the power density of the motor; secondly, the annular part of the silicon steel sheet and the rotor bracket made of different materials are connected and fixed together through structures such as the limiting ring plate and the positioning ring plate, which meets the axial and radial connection strength of the rotor and is easy to assemble; thirdly, the setting of the first reinforcing ring plate and the second reinforcing ring plate improves the mechanical strength of the rotor, compensates for the strength damage caused by the hollow magnetic isolation part, and at the same time reduces the coverage of the magnetic steel, thereby eliminating the harm caused by the falling of the magnetic steel. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] FIG1 is a front view of the annular portion of a silicon steel sheet according to the present invention.

[0043] FIG2 is an exploded view of the structure of the rotor core of the present invention.

[0044] FIG3 is a structural diagram of the rotor core in the present invention.

[0045] FIG4 is an axial cross-sectional view of the motor of the present invention.

[0046] FIG5 is a structural diagram of the motor of the present invention with part of the housing removed.

[0047] FIG6 is a structural diagram of the stator core and the insulation assembly assembled together in the present invention.

[0048] FIG7 is an enlarged view of A in FIG6 .

[0049] FIG8 is a structural diagram of the stator in the present invention.

[0050] FIG9 is a structural diagram of the insulating components of the present invention assembled together.

[0051] FIG10 is an exploded view of the structure of the insulation assembly of the present invention.

[0052] FIG11 is a structural diagram of the present invention without the rear end cover.

[0053] FIG12 is a structural exploded view of the present invention.

[0054] FIG13 is a structural diagram of the present invention without the rear end cover.

[0055] Explanation of Reference Numerals: Casing 1; Middle casing 11, front cover 12, rear cover 13, drain hole 131, pressure plate 14, flat key 15, blocking bolt 16, mounting seat 17; Restricting ring 111, keyway 112, water collection groove 113, mounting foot 114; Stator 2; Stator core 21, coil 22, stator keyway 23; Stator teeth 211, pole shoe 2111, tooth slot 212; Rotor 3; Rotor core 31, silicon steel sheet annular portion 32, rotor bracket 33, magnet 34, positioning ring plate 36, first locking piece 361, positioning flat key 37, bearing 38, drive shaft hole 39; magnet positioning ring 321, bracket fixing ring 322, connecting beam 323, hollow magnetic isolation portion 324, magnet groove 325, magnetic isolation bridge 326, magnetic pole 327, reinforced positioning hole 3271, top block 328, rotor keyway 329; drive shaft cylinder 331, limiting ring plate 332, mounting groove 333; first reinforcing annular plate 351, second reinforcing annular plate 352, locking through-hole 353, second locking piece 354, reinforcing through-hole 355; slot insulation frame 4, insulating bottom wall 41, insulating side wall 42, limiting rib 43, notch 431; insulating cover paper 5, insulating top 51, insulating side portion 52; slot wedge 6. DETAILED DESCRIPTION

[0056] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0057] Referring to Figures 1 to 5 and Figures 12 and 13 , an embodiment of a semi-direct-drive permanent magnet synchronous motor for an oil pumping unit according to the present invention includes a housing 1, a stator 2 disposed within the housing 1, and a rotor 3. The rotor 3 includes a rotor core 31, magnetic steel slots 325 disposed on the rotor core 31, and magnets 34 disposed within the magnetic steel slots 325. A magnetic isolation bridge 326 is provided on a side of the magnetic steel slots 325 near the outer edge of the rotor core 31, and a hollow magnetic isolation portion 324 is provided on a side of the magnetic steel slots 325 near the middle of the rotor core 31. A magnetic pole 327 is provided between two adjacent magnetic steel slots 325. The two magnets 34 on either side of the magnetic pole 327 have the same polarity on the sides opposite the magnetic pole 327. That is, the opposing surfaces of the two magnets 34 facing the magnetic pole 327 have the same polarity. The present invention provides a magnetic isolation bridge 326 on the outer edge of the rotor core 31 and a hollow magnetic isolation portion 324 on the side of the magnet 34 near the middle of the rotor core 31. This effectively suppresses magnetic flux leakage from the magnet 34. In particular, the hollow magnetic isolation portion 324 not only isolates magnetic flux but also reduces the weight of the rotor core 31. This helps reduce the copper loss of the motor, the iron loss of the rotor 3, and other stray losses. Furthermore, large motors have relatively high power and load, resulting in poorer heat dissipation performance than small motors. Therefore, the above-mentioned magnetic isolation measures can reduce the thermal load of the motor during operation, increase the motor's service life and operating stability, and have significant practical significance for the efficient operation of large motors. Finally, the two magnets 34 on either side of the magnetic pole 327 have the same polarity on the side opposite the magnetic pole 327. This structure allows the magnetic flux of each magnetic pole 327 to be superimposed, greatly enhancing the rotor magnetomotive force of each magnetic pole 327, further increasing the air gap magnetic density, and thus increasing the power density of the motor.

[0058] Referring to Figures 1 to 3 , according to the above-described embodiment of the invention, the rotor core 31 includes a silicon steel annular portion 32 and a rotor support 33 fixed in the middle of the silicon steel annular portion 32. Magnets 34 and magnetic poles 327 are both provided on the silicon steel annular portion 32. A drive shaft 331 is provided in the middle of the rotor support 33. The drive shaft 331 and rotor support 33 are integrally formed. The ends of the drive shaft 331 are movably mounted to the motor housing 1 via bearings 38. A drive shaft hole 39 is formed in the middle of the drive shaft 331. When used in a motor, the rotor 3 with this structure can be rotated by coupling the drive shaft hole 39 with the driven shaft of another device. Therefore, the rotor 3 in the present invention adopts this structure, which can reduce the amount of silicon steel sheets used and reduce production costs without affecting the performance of the rotor 3; at the same time, compared with the solution of setting a drive shaft hole 39 on multiple stacked silicon steel sheets and connecting them to an external driven shaft, it is more stable and reliable. The drive shaft tube 331 in the present invention is easier to set up a connection structure for matching the driven shaft; for this type of split structure and rotor core 31 with different material combinations, the setting of the hollow magnetic isolation part 324 can effectively suppress the leakage of magnets 34 near the middle of the rotor 3, thereby improving the reliability of the motor.

[0059] Referring to Figures 1 and 2 , according to the aforementioned embodiment of the invention, the silicon steel sheet annular portion 32 includes a magnetic steel positioning ring 321 and a bracket fixing ring 322 disposed inside the magnetic steel positioning ring 321. Multiple connecting beams 323 are evenly spaced between the magnetic steel positioning ring 321 and the bracket fixing ring 322. The ends of the connecting beams 323 connect the magnetic steel positioning ring 321 and the bracket fixing ring 322, respectively. A hollow magnetic isolation portion 324 is formed between adjacent connecting beams 323. The hollow magnetic isolation portion 324 formed using the aforementioned structure is easy to manufacture, has a large hollow area, and provides excellent magnetic isolation.

[0060] Referring to Figures 1 and 2 , according to the aforementioned embodiment of the invention, a top block 328 is provided in the hollowed-out magnetic isolation portion 324 at a location opposite the magnetic steel slot 325. One end of the top block 328 is connected to the bracket fixing ring 322, while the other end of the top block 328 is free and rests against the inner side of the magnetic steel 34. The contact area between the top block 328 and the magnetic steel 34 is smaller than the inner side of the magnetic steel 34, and the hollowed-out magnetic isolation portion 324 communicates with the magnetic steel slot 325. This structure maximizes the hollowed-out area while ensuring stable installation of the magnetic steel 34, particularly reducing the overhanging area on the inner side of the magnetic steel 34, thereby significantly improving the magnetic isolation effect of the magnetic steel 34.

[0061] Referring to Figures 1 and 2 , according to the aforementioned embodiment of the invention, a positioning key 37 is provided on the outer wall of the rotor support 33, and a rotor keyway 329 is provided on the inner wall of the silicon steel annular portion 32. A positioning ring plate 36 is also provided. A limiting ring plate 332 is provided at one end of the rotor support 33. The outer diameters of both the limiting ring plate 332 and the positioning ring plate 36 are larger than the inner diameter of the silicon steel annular portion 32. The other end of the rotor support 33 is inserted into the silicon steel annular portion 32, i.e., inside the support fixing ring 322. The positioning key 37 is inserted into the rotor keyway 323. The limiting ring plate 332 abuts one side of the silicon steel annular portion 32, while the positioning ring plate 36 abuts the other side of the silicon steel annular portion 32 and is connected to the rotor support 33 via a first locking member 361. Both the positioning ring plate 36 and the rotor support 33 are provided with locking holes for the first locking member 361 to pass through. In this embodiment, the first locking member 361 is preferably a bolt. The outer wall of the rotor support 33 is provided with a mounting slot 333, into which a positioning key 37 is screwed, projecting beyond the slot. This structure of positioning key 37 simplifies the manufacturing process of the rotor support 33. Positioning keys 37 of varying thicknesses can be used to accommodate the depth of the rotor keyway 329 on the silicon steel sheet annular portion 32. This structure secures the silicon steel sheet annular portion 32 and the rotor support 33, ensuring both axial and radial strength of the rotor 3, while also facilitating assembly.

[0062] Referring to Figures 1 to 3 , according to the above-described embodiment of the invention, a first reinforcing annular plate 351 and a second reinforcing annular plate 352 are provided on either side of the rotor core 31. The second locking member 354 also includes a second locking member 354. The second locking member 354 sequentially passes through the first reinforcing annular plate 351, the rotor core 31, and the first reinforcing annular plate 351, locking them together. The first reinforcing annular plate 351 and the first reinforcing annular plate 351 cover both sides of the magnetic steel slot 325. The first and second reinforcing annular plates 351 and 352 are each provided with a locking through-hole 353. The second locking member 354 passes through the locking through-hole 353 and the hollow magnetic isolation portion 324, respectively, to secure the magnet 325. In this embodiment, the second locking member 354 is preferably a bolt. The provision of the first and second reinforcing annular plates 351 and 352 improves the mechanical strength of the rotor 3, compensating for the strength loss caused by the hollow magnetic isolation portion 324, while also reducing the coverage of the magnetic steel 34 and preventing the damage caused by the magnetic steel 34 falling off. Finally, the hollow magnetic isolation portion 324 provides a passing portion for the second locking member 354 , thereby improving assembly efficiency and reducing component manufacturing difficulty.

[0063] Referring to Figures 2 and 3, according to the above-mentioned embodiment of the invention, a reinforcing positioning member is also included. The first reinforcing annular plate 351 and the second reinforcing annular plate 352 are both provided with reinforcing through-holes 355, and at least part of the magnetic poles 327 are both provided with reinforcing positioning holes 3271. The reinforcing positioning member passes through the reinforcing through-holes 355 and the reinforcing positioning holes 3271 in sequence to reinforce and fix the first reinforcing annular plate 351 and the second reinforcing annular plate 352 to the magnetic poles 327. In this embodiment, the reinforcing positioning member is preferably a rivet. This structure improves the connection strength between each magnetic pole 327, and at the same time improves the overall mechanical strength of the rotor core 31. While meeting the outer side limit of the magnetic steel 34, the magnetic isolation bridge 326 can be made thinner to improve the magnetic isolation effect.

[0064] 1 , according to the above embodiment of the invention, the magnetic pole 327 is a fan-shaped structure.

[0065] Referring to Figures 1 and 2 , according to the aforementioned embodiments of the present invention, the silicon steel sheet annular portion 32 is formed from a stack of multiple, integrally formed silicon steel sheets. Compared to the prior art rotor 3, where the magnetic poles 327 are separate and individually mounted on the core, this structure of the silicon steel sheet annular portion 32 allows for higher design precision of the magnetic poles 327 and magnets 34, ensuring stable motor operation.

[0066] 6 to 11 , according to an embodiment of the semi-direct drive permanent magnet synchronous motor for an oil pumping unit provided by the invention, the housing 1 includes a middle housing 11, a front cover 12 and a rear cover 13 provided at both ends of the middle housing 11; the stator 2 includes a stator core 21, a plurality of stator teeth 211 are evenly arranged on the stator core 21, and tooth slots 212 are formed between adjacent stator teeth 211. Coils 22 are wound around the stator teeth 211, and the coils 22 pass through the tooth slots 212 during the winding process; the radial cross-section of the tooth slots 212 is The stator teeth 211 are trapezoidal in shape, with the free ends of the stator teeth 211 extending into the tooth slots 212 on either side to form pole shoes 2111. The tooth slots 212 are equipped with an insulation assembly comprising a slot insulation frame 4, an insulation cover paper 5, and a slot wedge 6. The outer wall of the slot insulation frame 4 fits in place with the inner wall of the tooth slots 212. The slot wedge 6 is located at the mouth of the tooth slot 212 and presses against the coil 22. The ends of the slot wedge 6 are limitedly engaged with the pole shoes 2111. The insulation cover paper 5 is located between the coil 22 and the slot wedge 6 to insulate them. Both the front cover 12 and the rear cover 13 are provided with shaft holes. A drive shaft hole 39 is provided in the middle of the rotor 3, facing the shaft holes in the front cover 12 and the rear cover 13. The present invention adopts the above-mentioned tooth slot 212 insulation component with the following advantages: 1. Simple structure, easy assembly, low production cost, can be installed in place at one time, and no subsequent trimming, cutting and other processes are required; 2. Since the slot insulation skeleton 4 can fit the inner wall of the tooth slot 212, and the slot insulation skeleton 4 is made of a fixed material, the winding can completely fit the inner wall of the slot insulation skeleton 4, and no gaps will be generated at the corners, thereby ensuring the utilization rate of the tooth slot 212 area, thereby improving the slot fill rate and the power density of the motor; 3. Compared with the existing technology, the slot insulation skeleton 4 is used at the part where the insulating paper is most easily damaged, thereby eliminating the problem of insulation failure of the inner wall of the tooth slot 212; 4. Since the two ends of the winding of the stator 2 assembly in the semi-direct drive permanent magnet synchronous motor for the pumping unit need to be subjected to very strict shaping and flattening, the present invention adopts the tooth slot 212 insulation component to avoid the fact that its corners are often easily damaged during the shaping process, causing leakage of the product and failing to pass the voltage withstand test and insulation resistance standard requirements.

[0067] Referring to Figures 7, 9 and 10, according to the above-mentioned embodiment of the invention, the slot insulation skeleton 4 includes an insulating bottom wall 41 and insulating side walls 42 provided on both sides of the insulating bottom wall 41. The insulating bottom wall 41 is in contact with the bottom wall of the tooth groove 212, and the insulating side walls 42 are in contact with the side walls of the tooth groove 212. The slot insulation skeleton 4 is a U-shaped structure. The slot insulation skeleton 4 is injection molded with a high-temperature resistant, high-strength and high-stability injection molding material. The present invention preferably uses nylon material. The above-mentioned slot insulation skeleton 4 has a simple structure, is easy to process and produce, and has a cost that is basically the same as that of insulating paper. The structure of injection molding ensures the accuracy and plasticity of the slot insulation skeleton 4, and can fit the inner wall of the tooth groove 212.

[0068] Referring to FIG. 7 , according to the above-described embodiment of the invention, one end of the insulating side wall 42 is connected to the insulating bottom wall 41, and the other end abuts the base of the pole piece 2111. This facilitates positioning of the slot insulating frame 4 within the tooth slot 212 and prevents interference between the slot insulating frame 4 and the slot wedge 6, ensuring secure installation of the slot wedge 6.

[0069] Referring to Figures 8 to 10 , according to the aforementioned embodiments of the invention, the slot insulation frame 4 extends axially from the slots 212 at both ends and forms limiting ribs 43, which engage the axial edges of the slots 212. The limiting ribs 43 help position the slot insulation frame 4 within the slots 212, preventing axial movement. The limiting ribs 43 thicken the exposed edges of the slot insulation frame 4, preventing tearing during stator 2 shaping, which could lead to potential leakage. Furthermore, the limiting ribs 43 serve as reinforcement and shaping ribs for the slot insulation frame 4, enhancing its structural stability and facilitating production and assembly.

[0070] Referring to Figure 10 , according to the aforementioned embodiment of the invention, retaining ribs 43 are provided on the insulating bottom wall 41 and the insulating side walls 42. A notch 431 is formed in the middle of the retaining rib 43 on the insulating bottom wall 41. This structure reduces the plastic strength of the insulating bottom wall 41. During assembly, workers can easily pinch the two insulating side walls 42 together, causing the insulating bottom wall 41 to elastically deform and easily fit into the tooth groove 212. Once in the tooth groove 212, the insulating bottom wall 41 returns to its original shape and fits against the bottom wall of the tooth groove 212. This structure helps improve the installation efficiency of the slot insulating frame 4.

[0071] Referring to Figures 7 to 13 , according to the above-described embodiment of the invention, the insulating cover paper 5 includes an insulating top 51 and insulating side portions 52 disposed at either end of the insulating top 51. The insulating top 51 contacts the slot wedge 6, while the insulating side portions 52 are inserted into the slot insulation frame 4 and rest against the inner wall of the slot insulation frame 4. After installation, the insulating cover paper 5 forms a U-shaped structure that rests against the inner wall of the slot insulation frame 4, ensuring reliable insulation.

[0072] 7 and 8 , according to the above-mentioned embodiment of the invention, both axial ends of the insulating cover paper 5 and the slot wedge 6 extend out of the slot 212. This structure helps to improve the insulation effect between the coil 22 and the slot 212, thereby increasing the product yield.

[0073] 12 and 13 , according to an embodiment of an easy-to-assemble semi-direct-drive permanent magnet synchronous motor for an oil pumping unit provided by the utility model, the middle shell 11 and the stator 2 are in transition fit, and a limiting ring 111 is provided on the inner wall of the middle shell 11 along the circumferential direction. One end of the stator 2 rests on the limiting ring 111 and is fixedly connected to the limiting ring 111 by a locking member. The locking piece is a bolt. The above scheme sets the middle shell 11 and the stator 2 as a transition fit. The principle of selecting the transition fit is that the limit deviation of the outer diameter of the stator 2 is designed according to p8, and the limit deviation of the inner diameter of the matching surface of the middle shell 11 is designed according to H8, so that the maximum clearance and maximum interference of the generated transition fit are guaranteed to be within a relatively reasonable range; the smoothness of the process of inserting the stator 2 into the middle shell 11 is guaranteed, the product processing precision is high, and there is no need to use a critical hammer when inserting the stator 2 into the middle shell 11 to avoid damage to the stator 2 or invisible damage, which would bury hidden dangers for later use. The product yield is high, which helps to reduce production costs; at the same time, a locking piece is used to lock the stator 2 and the limit ring 111 together. The setting of the limit ring 111 also helps the stator 2 to be quickly installed in place in the middle shell 11, eliminating the process of axial adjustment of the stator 2. It is only necessary to ensure that one end of the stator 2 is against the limit ring 111 and locked with a locking piece. The fixation is firm and convenient, the overall assembly efficiency is high, and the maintenance of the stator 2 is convenient in the later stage.

[0074] Referring to Figures 12 and 13 , according to the aforementioned embodiment of the utility model, a pressure plate 14 is provided at the other end of the stator 2. The locking member passes through the pressure plate 14 and the stator 2 in sequence, and is secured to the retaining ring 111. The provision of the pressure plate 14 ensures that the force applied to the edge of the other end of the stator 2 is more evenly distributed, thus preventing the bolts from causing damage to the stator 2.

[0075] Referring to Figures 12 and 13 , according to the aforementioned embodiment of the utility model, the pressure plate 14 has an arc-shaped structure. Multiple pressure plates 14 are evenly positioned against the edge of the stator 2, with gaps formed between adjacent pressure plates 14. This split, arc-shaped structure of the pressure plate 14 makes assembly more flexible and simple, helping to reduce the production cost of the pressure plate 14 and avoid significant waste of sheet material, further reducing production costs. Bolt holes are provided on the pressure plate 14, the stator 2, and the retaining ring 111.

[0076] Referring to Figures 12 and 13 , according to the aforementioned embodiment of the utility model, a flat key 15 is provided on the inner wall of the middle housing 11, and a stator key slot 23 is provided on the outer wall of the stator 2. The flat key 15 engages with the stator key slot 23 in a position-limiting manner. The provision of the flat key 15 strengthens the connection between the middle housing 11 and the stator 2, reduces the stress on the locking member, improves the reliability and stability of the product, and enhances the product's installation accuracy.

[0077] Referring to Figures 12 and 13 , according to the aforementioned embodiment of the utility model, a keyway 112 is provided on the inner wall of the middle shell 11. The bottom end of a flat key 15 is inserted into this keyway 112 and secured to the middle shell 11, while the top end of the flat key 15 is exposed and protrudes from the keyway 112. The flat key 15 is secured to the keyway 112 via bolts. This split-body structure of the flat key 15 on the middle shell 11 facilitates the machining and casting of the middle shell 11, providing greater flexibility in installation. Furthermore, the size and height of the flat key 15 can be flexibly adjusted and replaced based on actual needs.

[0078] 12 and 13 , according to the above-mentioned embodiment of the utility model, a flat key 15 is provided on the inner wall of the middle shell 11 near the bottom, a water accumulation groove 113 is provided on the limiting ring 111 at a position corresponding to the flat key 15, and a drainage hole 131 is provided at a position opposite to the water accumulation groove 113 on the front cover 12 or the rear cover 13. The drainage hole 131 in this embodiment is provided on the rear cover 13, and a removable blocking bolt 16 is provided in the drainage hole 131. Since this product is mainly used to provide power for outdoor oil pumping units, it is inevitable that rainwater and fog will enter the casing 1 through the gap in the rotating shaft to form accumulated water in the long-term harsh outdoor environment. The design of the water accumulation groove 113 can make the water vapor entering the casing 1 accumulate at the bottom of the casing 1, effectively avoiding the contact between the accumulated water and the stator 2 coil 22, thereby improving the stability of product operation; at the same time, the setting of the drainage hole 131 and the blocking bolt 16 facilitates the discharge of accumulated water, and the drainage process is simple and convenient; the water accumulation groove 113 is arranged relative to the flat key 15, so that the water accumulation groove 113 is adjacent to the key groove 112, which facilitates the grooving process, avoids the frequent displacement of this large middle casing 11, and improves the safety of the production process.

[0079] Referring to Figures 12 and 13 , according to the aforementioned embodiments of the utility model, the middle shell 11 is an integrally formed structure. Compared to the prior art structure in which the shell is welded together in separate pieces, the precision of the shell inner diameter can be easily controlled, effectively avoiding problems such as a large gap between the middle shell 11 and the stator 2, or problems such as a too small gap requiring brute force installation or poor reliability.

[0080] Referring to Figures 12 and 13 , according to the aforementioned embodiments of the utility model, the middle housing 11 and the retaining ring 111 are integrally formed. The retaining ring 111 serves as an intermediate member connecting the middle housing 11 and the stator 2. Its integral molding with the middle housing 11 facilitates processing, provides high mechanical strength, and ensures a strong connection between the stator 2 and the middle housing 11.

[0081] 12 and 13 , according to the above embodiment of the utility model, the middle housing 11 is a through-type structure. For such large motors, the through-type structure of the middle housing 11 is convenient for processing, assembly and maintenance.

[0082] Referring to Figures 12 and 13 , according to the aforementioned embodiment of the utility model, both the front cover 12 and the rear cover 13 are provided with shaft holes. A drive shaft hole 39 is provided in the center of the rotor 3, which faces the shaft holes in the front cover 12 and the rear cover 13. The outer shell also includes a mounting base 17, and mounting legs 114 are provided at the bottom of the middle shell 11. Mounting legs 114 are fixedly connected to the mounting base 17. This provides easy assembly, high stability, and a wide range of adaptability.

[0083] The technical solution provided by the present invention is introduced in detail above. Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. The words such as front, back, left, right, positive and negative in this solution are all used to clearly express the terms from a certain perspective. At the same time, for those skilled in the art, according to the ideas of the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A semi-direct-drive permanent magnet synchronous motor for a pumping unit, comprising a motor housing, a stator and a rotor arranged inside the motor housing, wherein the rotor comprises a rotor core, a magnet groove arranged on the rotor core and a magnet arranged in the magnet groove, and is characterized in that, A magnetic isolation bridge is provided on one side of the permanent magnet groove close to the outer edge of the rotor core, and a hollowed-out magnetic isolation part is provided on one side of the permanent magnet groove close to the middle of the rotor core. A magnetic pole is provided between two adjacent permanent magnet grooves. The two permanent magnets on both sides of the magnetic pole have the same polarity on the side opposite to the magnetic pole.

2. The semi-direct-drive permanent magnet synchronous motor for pumping units according to claim 1, characterized in that The rotor core includes a silicon steel sheet annular part and a rotor bracket fixed in the middle of the silicon steel sheet annular part. The permanent magnets and the magnetic poles are both arranged on the silicon steel sheet annular part.

3. The semi-direct-drive permanent magnet synchronous motor for pumping units according to claim 2, characterized in that, The silicon steel sheet annular part includes a permanent magnet positioning ring and a bracket fixing ring arranged inside the permanent magnet positioning ring. A plurality of connecting beams are evenly arranged between the permanent magnet positioning ring and the bracket fixing ring. The hollowed-out magnetic isolation part is formed between two adjacent connecting beams.

4. The semi-direct drive permanent magnet synchronous motor for pumping unit according to claim 3, characterized in that, A top block is provided at a position of the hollowed-out magnetic isolation part opposite to the permanent magnet groove. One end of the top block is connected to the bracket fixing ring, and the other end of the top block abuts against the inner side surface of the permanent magnet. The contact area between the top block and the permanent magnet is smaller than the area of the inner side surface of the permanent magnet. The hollowed-out magnetic isolation part communicates with the permanent magnet groove.

5. The semi-direct-drive permanent magnet synchronous motor for pumping units according to claim 2, wherein, A positioning flat key is provided on the outer side wall of the rotor bracket, and a rotor key groove is provided on the inner side wall of the silicon steel sheet annular part; It further includes a positioning ring plate. A limiting ring plate is provided at one end of the rotor bracket. The outer diameters of the limiting ring plate and the positioning ring plate are both larger than the inner diameter of the silicon steel sheet annular part; The other end of the rotor bracket is inserted into the silicon steel sheet annular part. The positioning flat key is inserted into the rotor key groove. The limiting ring plate abuts against one side of the silicon steel sheet annular part, and the positioning ring plate abuts against the other side of the silicon steel sheet annular part and is connected to the rotor bracket through a first locking member.

6. The semi-direct drive permanent magnet synchronous motor for pumping unit according to claim 1, characterized in that, First reinforcing annular plates and second reinforcing annular plates are provided on both sides of the rotor core. It further includes a second locking member. The second locking member sequentially passes through the first reinforcing annular plate, the rotor core and the first reinforcing annular plate and locks them together. The first reinforcing annular plate and the first reinforcing annular plate cover both sides of the permanent magnet groove.

7. The semi-direct drive permanent magnet synchronous motor for pumping units according to claim 6, characterized in that, Locking through holes are provided on both the first reinforcing annular plate and the second reinforcing annular plate. The second locking member is respectively fixed by passing through the locking through holes and the hollowed-out magnetic isolation part.

8. The semi-direct drive permanent magnet synchronous motor for pumping units according to claim 6, characterized in that, It further includes a reinforcing positioning member. Reinforcing through holes are provided on both the first reinforcing annular plate and the second reinforcing annular plate. Reinforcing positioning holes are provided on at least part of both sides of the magnetic pole. The reinforcing positioning member sequentially passes through the reinforcing through holes and the reinforcing positioning holes to strengthen and fix the first reinforcing annular plate and the second reinforcing annular plate to the magnetic pole.

9. The semi-direct-drive permanent magnet synchronous motor for pumping unit according to any one of claims 1-8, characterized in that, The magnetic pole is of a sector structure.

10. The semi-direct-drive permanent magnet synchronous motor for pumping units according to any one of claims 1-8, characterized in that, The silicon steel sheet annular part is formed by stacking a plurality of integrally formed silicon steel sheets.

11. The semi-direct-drive permanent magnet synchronous motor for pumping units according to any one of claims 1-8, characterized in that, The housing includes a middle housing, a front end cover and a rear end cover provided at both ends of the middle housing; The stator includes a stator core. A plurality of stator teeth are evenly provided on the stator core. Tooth grooves are formed between adjacent stator teeth. Coils are wound on the stator teeth. The coil winding passes through the tooth grooves during the winding process; It is characterized in that the radial cross-section of the tooth groove is trapezoidal. The free ends of the stator teeth extend towards the tooth grooves on both sides to form pole shoes. A tooth groove insulation assembly is provided in the tooth groove. The tooth groove insulation assembly includes a groove insulation skeleton, insulating cover paper and a groove wedge. The outer wall of the groove insulation skeleton fits with the inner wall of the tooth groove. The groove wedge is located at the mouth of the tooth groove and presses the coil. Both ends of the groove wedge are in limit fit with the pole shoes. The insulating cover paper is located between the coil and the groove wedge to insulate and isolate the two.

12. The semi-direct-drive permanent magnet synchronous motor for pumping unit according to claim 11, wherein, The groove insulation skeleton includes an insulating bottom wall and insulating side walls provided on both sides of the insulating bottom wall. The insulating bottom wall abuts against the bottom wall of the tooth groove, and the insulating side walls abut against the side walls of the tooth groove.

13. The semi-direct-drive permanent magnet synchronous motor for pumping units according to claim 12, characterized in that, One end of the insulating side wall is connected to the insulating bottom wall, and the other end abuts against the root of the pole shoe.

14. The semi-direct-drive permanent magnet synchronous motor for pumping units according to claim 12, wherein, Axial ends of the slot insulating skeleton extend out of the slot and form limiting ribs, and the limiting ribs are snap-fitted on the axial edges of the slot.

15. The semi-direct-drive permanent magnet synchronous motor for pumping units according to claim 14, characterized in that, The limiting ribs are arranged on the insulating bottom wall and the insulating side wall, and a notch is formed in the middle of the limiting rib located on the insulating bottom wall.

16. The semi-direct drive permanent magnet synchronous motor for pumping unit according to claim 11, characterized in that, The insulating cover paper includes an insulating top and insulating side parts provided at both ends of the insulating top. The insulating top contacts the slot wedge, and the insulating side parts are inserted into the slot insulating skeleton and lean against the inner wall of the slot insulating skeleton.

17. The semi-direct-drive permanent magnet synchronous motor for pumping units according to claim 11, characterized in that, Axial ends of both the insulating cover paper and the slot wedge extend out of the slot.

18. The semi-direct-drive permanent magnet synchronous motor for pumping units according to claim 11, wherein, Axial holes are provided on both the front end cover and the rear end cover, a driving shaft hole is provided in the middle of the rotor, and the driving shaft hole is opposite to the axial holes on the front end cover and the rear end cover.

19. The semi-direct drive permanent magnet synchronous motor for pumping unit according to claim 11, wherein The middle shell and the stator are in a transition fit. A limiting ring is arranged along the circumference on the inner wall of the middle shell. One end of the stator abuts against the limiting ring and is fixedly connected to the limiting ring through a locking member.

20. The semi-direct drive permanent magnet synchronous motor for pumping unit according to claim 19, wherein, A pressing plate is provided at the other end of the stator. The locking member sequentially passes through the pressing plate and the stator and then is fixed to the limiting ring.

21. The semi-direct drive permanent magnet synchronous motor for pumping units according to claim 20, wherein, The pressing plate is of an arc-shaped structure. There are multiple pressing plates which are evenly attached to the edge of the stator, and a gap is formed between two adjacent pressing plates.

22. The semi-direct-drive permanent magnet synchronous motor for pumping units according to claim 19, characterized in that, A flat key is provided on the inner wall of the middle shell, and a stator key groove is provided on the outer wall of the stator. The flat key and the key groove are in a limiting fit.

23. The semi-direct drive permanent magnet synchronous motor for pumping units according to claim 22, characterized in that, A key groove is provided on the inner wall of the middle shell. The bottom end of the flat key is inserted into the key groove and fixed to the middle shell, and the top end of the flat key is exposed and protrudes from the key groove.

24. The semi-direct drive permanent magnet synchronous motor for pumping unit according to claim 22, characterized in that, The flat key is arranged on the inner wall of the middle shell near the bottom. A water accumulation groove is provided at the position corresponding to the flat key on the limiting ring. A drain hole is provided at the position of the front end cover or the rear end cover opposite to the water accumulation groove, and a detachable plug bolt is provided in the drain hole.

25. The semi-direct drive permanent magnet synchronous motor for pumping unit according to any one of claims 19-24, characterized in that, The middle shell is of an integrally formed structure.

26. The semi-direct drive permanent magnet synchronous motor for pumping units according to any one of claims 19-24, characterized in that, The middle shell and the limiting ring are of an integrally formed structure.

27. The semi-direct drive permanent magnet synchronous motor for pumping unit according to any one of claims 19-24, characterized in that The middle shell is of a structure that is penetrated from left to right.

28. The semi-direct-drive permanent magnet synchronous motor for pumping units according to any one of claims 19-24, characterized in that, The outer shell further includes a mounting seat. Mounting feet are provided at the bottom of the middle shell, and the mounting feet are fixedly connected to the mounting seat.

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