Shell-free permanent magnet synchronous motor

Abstract

The utility model relates to the field of permanent magnet synchronous motors, in particular to a permanent magnet synchronous motor without a shell. Comprising a rear end cover, a stator, a Hall plate, a rotor and a speed reducer, a motor shaft is sequentially sleeved with the rotor and the stator from inside to outside, the motor shaft is sealed in the motor through the rear end cover, specifically, the stator comprises a stator disc set, and one side of the stator disc set comprises Hall positions which are continuously arranged; the Hall plate comprises a circuit board and at least two Hall elements, the Hall elements are vertically inserted in the circuit board, the circuit board is fixed between the stator and the speed reducer, and the Hall elements are contained in the Hall positions so that cables on the Hall plate can be led out through the side edge of the permanent magnet synchronous motor. According to the utility model, a housing is not used to improve the heat dissipation efficiency of the permanent magnet synchronous motor, and the fixed position of the Hall plate is changed, so that the Hall plate cable and the motor driving cable can be led out from the wire outlet groove at the side surface during wiring.

Description

Technical Field

[0001] This utility model relates to the field of permanent magnet synchronous motors, and in particular to a permanent magnet synchronous motor without a casing. Background Technology

[0002] Permanent magnet synchronous motors (PMSMs) use permanent magnets for excitation, simplifying the motor structure, reducing processing and assembly costs, and eliminating the need for potentially problematic slip rings and brushes, thus improving operational reliability. Furthermore, the absence of excitation current and excitation losses increases efficiency and power density. A PMSM consists of a stator, rotor, and end covers. The stator is essentially the same as a conventional induction motor, employing a laminated structure to reduce iron losses during operation. The rotor can be solid or made of laminated laminations. The armature winding can use concentrated full-pitch windings, distributed short-pitch windings, or unconventional windings.

[0003] The housing of a permanent magnet synchronous motor provides stable support and fixation for the core components inside the motor, such as the stator and rotor, ensuring that these components maintain the correct relative position and stable operating state during motor operation. As an external barrier, it effectively prevents dust, moisture, impurities, and other contaminants from entering the motor, thereby protecting the internal electronic components and mechanical parts from damage.

[0004] However, the heat generated by the operation of the permanent magnet synchronous motor causes the ambient temperature inside the casing to rise. Due to the thermal pressure connection between the stator and the casing, it is easy for a single stator to shift, causing abnormal motor operation.

[0005] Therefore, how to overcome the defects of the existing technology and solve the problem of abnormal operation of permanent magnet synchronous motor caused by the thermal pressure connection between the stator and the housing is an urgent problem to be solved in this technical field. Utility Model Content

[0006] In view of the above-mentioned defects or improvement needs of the existing technology, this utility model solves the problem of abnormal operation of permanent magnet synchronous motor caused by the thermal pressing connection between the stator and the shell in the existing permanent magnet synchronous motor with shell.

[0007] The technical solution adopted in this embodiment of the utility model is as follows:

[0008] In a first aspect, this utility model provides a casingless permanent magnet synchronous motor, including a rear end cover, a stator, a Hall plate, a rotor, and a reducer. The rotor and stator are sequentially sleeved on the motor shaft from the inside out. The rear end cover seals the motor shaft inside the motor. Specifically, the stator includes a stator platter assembly, and one side of the stator platter assembly includes continuously arranged Hall positions. The Hall plate includes a circuit board and at least two Hall elements. The Hall elements are vertically inserted into the circuit board, and the circuit board is fixed between the stator and the reducer. The Hall elements are accommodated in the Hall positions to facilitate the routing of cables on the Hall plate through the side of the permanent magnet synchronous motor.

[0009] Preferably, the stator includes an upper frame, a lower frame, a stator platter group, and at least one winding. Specifically, the stator platter group includes at least one stator platter a and at least one stator platter b, stator platter a and stator platter b are stacked and then pressed together, and stator platter b is close to the reducer; wherein, at least two consecutive Hall element slots are included between at least three adjacent windings on stator platter b, and the Hall element slots on all stator platters b are stacked to form a cavity-shaped Hall position, and the depth of the Hall position is greater than the height of the Hall element.

[0010] Preferably, the housing of the reducer extends toward the motor side to form a cavity flange, specifically including: a rear end cover, a stator, and a cavity flange fastened together; the circuit board of the Hall plate is fixed on the lower frame of the stator and placed in the cavity flange.

[0011] Preferably, a cable outlet groove is provided on one side of the cavity flange, and the permanent magnet synchronous motor further includes a wire pressing block and a waterproof gasket. Specifically, the wire pressing block and the waterproof gasket are fixed on the cavity flange so that when the cable in the permanent magnet synchronous motor is led out through the cable outlet groove, the gap between the cable outlet groove and the cable is sealed by the wire pressing block and the waterproof gasket.

[0012] Preferably, the permanent magnet synchronous motor further includes: placing O-rings at the upper and lower frame positions to ensure the seal between the stator and the cavity flange, and between the stator and the rear end cover.

[0013] Preferably, each of the stator discs a or b has at least one set of recessed grooves on its outer edge, specifically including: the recessed grooves extending in a direction parallel to the motor shaft direction, and the recessed grooves of all stator discs a or b in the stator disc group being aligned.

[0014] Preferably, the permanent magnet synchronous motor further includes a heat dissipation device, specifically: the heat dissipation device is fixed on the stator by an indented groove.

[0015] Preferably, the stator specifically includes: stator disc a and stator disc b are silicon steel stator discs, and the silicon steel stator discs are coated with insulating varnish; the upper frame and the lower frame are insulating engineering plastics with a strength higher than specified.

[0016] Preferably, the reducer is a worm gear reducer, wherein the reducer worm and the motor shaft of the permanent magnet synchronous motor are integrally formed and highly coaxial, specifically including: the motor shaft is fixed by bearings at both ends of the reducer worm, and the bearings at both ends of the reducer worm are enclosed inside the reducer by the reducer housing.

[0017] Preferably, the permanent magnet synchronous motor further includes: a reducer worm gear passing through a bearing at the end away from the stator and rotor; the bearing is provided with a keyway or flat protrusion at the end through which the reducer worm gear passes, so as to facilitate manual rotation of the reducer worm gear when the permanent magnet synchronous motor fails due to power failure.

[0018] Compared with the prior art, the beneficial effects of this utility model embodiment are as follows: by eliminating the use of a shell and adding an additional heat dissipation structure on the stator, the heat dissipation efficiency of the permanent magnet synchronous motor is improved, avoiding abnormal operation caused by insufficient heat dissipation; by changing the fixed position of the Hall plate, the routing length of the Hall plate to motor driver connection cable inside the motor is reduced, so that the Hall plate cable and the motor drive cable can be led out together from the side cable outlet groove during routing, thereby increasing the fixing strength of the cable; at the same time, the two cables share the space of the flange cavity, reducing the overall height of the motor. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the embodiments of this utility model will be briefly described below. Obviously, the drawings described below are merely some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without any creative effort.

[0020] Figure 1 This is a schematic diagram of a shell-less permanent magnet synchronous motor structure provided by an embodiment of the present invention;

[0021] Figure 2 This is a schematic diagram of the stator disc assembly in a shell-less permanent magnet synchronous motor provided in this embodiment of the present invention;

[0022] Figure 3 This is a schematic diagram of the stator structure in the shell-less permanent magnet synchronous motor provided in this embodiment of the utility model;

[0023] Figure 4 This is a schematic diagram of the structure of stator disc a in the shell-less permanent magnet synchronous motor provided in this embodiment of the present invention;

[0024] Figure 5 This is a schematic diagram of the structure of stator disc b in the shell-less permanent magnet synchronous motor provided in this embodiment of the present invention;

[0025] Figure 6This is a schematic diagram of the assembly method of stator disc a and stator disc b in the shell-less permanent magnet synchronous motor provided in this embodiment of the present invention;

[0026] Figure 7 This is a schematic diagram of the fixed position of the Hall plate in the shell-less permanent magnet synchronous motor provided in this embodiment of the utility model;

[0027] Figure 8 This is a schematic diagram of the cable lead-out method of the Hall plate in the shell-less permanent magnet synchronous motor provided in this utility model embodiment;

[0028] Figure 9 This is a schematic diagram of the recessed groove on the outer edge of stator disc a or stator disc b in the shell-less permanent magnet synchronous motor provided in this embodiment of the present invention;

[0029] Figure 10 This is a schematic diagram of the structure of the reducer worm gear and the motor shaft of the permanent magnet synchronous motor in the shell-less permanent magnet synchronous motor provided in this embodiment of the utility model;

[0030] Figure 11 This is a schematic diagram of the assembly method of the motor shaft in the shell-less permanent magnet synchronous motor provided in this embodiment of the utility model. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present utility model and are not intended to limit the present utility model.

[0032] This utility model is an architecture of a specific functional system. Therefore, the specific embodiments mainly describe the functional logic relationship of each structural module, and do not limit the specific software and hardware implementation methods.

[0033] Furthermore, the technical features involved in the various embodiments of this utility model described below can be combined with each other as long as they do not conflict with each other. The present utility model will now be described in detail with reference to the accompanying drawings and embodiments.

[0034] The stator core and related structures of a permanent magnet synchronous motor are called stator platters. The stator platters may generate heat due to various factors during operation.

[0035] (1) Electromagnetic effect: When a permanent magnet synchronous motor is working, the current in the stator winding generates an alternating magnetic field, which interacts with the magnetic field generated by the permanent magnet, thereby driving the rotor to rotate. During this process, the interaction of electromagnetic fields will lead to a certain amount of energy loss, which will eventually be released in the form of heat.

[0036] (2) Resistance heating: The stator winding itself has a certain resistance. When current flows through it, according to Joule's law (Q = I), 2 The windings (Rt) generate a certain amount of heat. This heat is one of the reasons for the temperature rise in the stator region.

[0037] (3) Core loss: Under the action of an alternating magnetic field, the stator core will generate eddy current loss and hysteresis loss, which will also be released in the form of heat. Especially when the stator core design is unreasonable or the material selection is inappropriate, the core loss may be more significant.

[0038] (4) Heat dissipation conditions: If the heat dissipation design of the motor is poor or the heat dissipation channel is blocked, the heat generated in the stator area cannot be dissipated in time, which will cause the temperature of the stator plate or stator area to rise further.

[0039] Traditional permanent magnet synchronous motors often employ better airflow designs to dissipate heat from the stator fins, but the presence of the motor casing still hinders heat dissipation.

[0040] In permanent magnet synchronous motors, an absolute encoder containing Hall elements is required to record the motor's position. The absolute encoder is typically integrated onto a circuit board, with the Hall element's pins vertically inserted into the board and its sensing end extending vertically out of the board. In this embodiment, the circuit board integrating the Hall element's absolute encoder is referred to as a Hall board.

[0041] In traditional permanent magnet synchronous motors, Hall effect sensors are typically located below the rear end cover. However, because the insulating varnish on the copper wires in the winding coils can be damaged during winding, potentially causing discharge to the end cover when energized, the rear end cover is usually made of insulating plastic to prevent discharge from damaged windings. Since the rear end cover is made of plastic, and the permanent magnet synchronous motor's cables need to be led out from it, the wire clamping block also needs to be fixed to the plastic rear end cover. During the use of the permanent magnet synchronous motor, the motor cables are frequently pulled, and the plastic rear end cover's fixation strength for the wire clamping block is insufficient, easily leading to cable detachment or damage to the rear end cover.

[0042] Example 1:

[0043] This embodiment provides a housing-less permanent magnet synchronous motor. By eliminating the housing and adding additional heat dissipation structures to the stator, the heat dissipation efficiency of the permanent magnet synchronous motor is improved, avoiding malfunctions caused by insufficient heat dissipation; and by changing the fixing position of the Hall plate and the cable lead-out position, the problem of insufficient strength of the plastic rear end cover is avoided.

[0044] The following is combined Figure 1The specific structure of the casing-less permanent magnet synchronous motor provided by this utility model is described. The casing-less permanent magnet synchronous motor provided in this embodiment includes: a rear end cover 17, a stator 4, a Hall plate 3, a rotor 2 and a reducer 1. The rotor 2 and the stator 4 are sequentially sleeved on the motor shaft 14 of the reducer 1 from the inside to the outside. The rear end cover 17 seals the motor shaft 14 inside the motor.

[0045] In this embodiment, the Hall plate 3 is fixed to the metal structure between the stator 4 and the reducer 1 to improve the fixing strength. Hall positions 41 are provided on the stator 4 to accommodate the Hall devices on the Hall plate 3. Figure 2 As shown, the stator 4 includes a stator platter assembly 42, and one side of the stator platter assembly 42 includes continuously arranged Hall effect positions 41. The Hall plate 3 includes a circuit board and at least two Hall elements 31, which are vertically inserted into the circuit board. The circuit board is fixed between the stator 4 and the reducer 1. The Hall elements 31 are housed in the Hall positions 41 to facilitate the routing of cables from the Hall plate 3 through the side of the permanent magnet synchronous motor. In practice, using continuously arranged Hall positions 41 helps to reduce the size of the Hall plate 3, thereby reducing circuit board and assembly costs. The number of Hall positions 41 can be set according to the specific number of Hall elements 31, or more Hall positions 41 can be reserved as needed. Figure 2 In the example of three Hall positions 41, two of the Hall positions 41 each contain a Hall element 31.

[0046] like Figure 3 As shown, the stator 4 includes an upper frame 43, a lower frame 44, a stator platter assembly 42, and at least one winding 45. The stator platter assembly 42 includes at least one stator platter a 421 and at least one stator platter b 422. Figure 4 The image shown is a top view of a stator disk a 421. Figure 5 The image shown is a top view of a stator platter b 422, which includes at least two consecutive Hall element slots 46 between at least three adjacent windings 45 on the stator platter b 422. Figure 5 In the stator disk b 422, there are three consecutive Hall element slots 46 between the four windings 45 adjacent to one side.

[0047] In practice, the thinner the single silicon steel stator dart, the more effectively eddy current losses can be reduced and energy efficiency improved; however, the thinner the silicon steel stator dart, the higher the cost. Considering both performance and cost, a 0.5mm silicon steel stator dart can meet the motor performance requirements; therefore, the preferred thickness of a single silicon steel stator dart is 0.5mm.

[0048] Stator discs a 421 and b 422 are stacked and then pressed together, with stator disc b 422 located near reducer 1. Stator discs a 421 and b 422 are silicon steel stator discs, coated with insulating varnish. Figure 6 As shown, in a specific implementation, the silicon steel stator disk assembly 42 is formed by stacking and bonding n silicon steel stator disks. These n silicon steel stator disks are specifically divided into X silicon steel stator disks a 421 and Y silicon steel stator disks b 422. The Hall element slots 46 on all stator disks b 422 are stacked to form a cavity-shaped Hall position 41. In actual implementation, the number of stator disks b 422 is determined based on the thickness of each stator disk b 422 and the height of the Hall element 31, ensuring that the depth of the Hall position 41 is greater than the height of the Hall element 31, thus providing sufficient space to accommodate the sensing end of the Hall element 31. In a specific scenario, each Hall position 41 has a depth of 4.0 mm and a width of 4.3 mm.

[0049] To provide sufficient fixing space and strength for the Hall plate 3, in the permanent magnet synchronous motor provided in this embodiment, the housing of the reducer 1 extends towards the motor side to form a cavity flange 13; the rear end cover 17, stator 4, and cavity flange 13 are fastened together. Through this fixing method, both the fins of the reducer housing 11 and the cavity flange 13 can be used for stator heat dissipation. In a specific implementation, the rear end cover 17, stator 4, and cavity flange 13 can be fastened together with four bolts. Furthermore, O-rings can be placed at the positions of the upper frame 43 and the lower frame 44 to ensure a seal between the stator 4 and the cavity flange 13, and between the stator 4 and the rear end cover 17.

[0050] The circuit board of Hall plate 3 is fixed on the lower frame 44 of stator 4 and placed in cavity flange 13. Figure 7 As shown, the Hall plate 3 is fixed on the lower frame 44 and placed in the cavity flange 13 between the stator 4 and the reducer 1. The pins of the Hall element 31 are vertically inserted into the absolute encoder circuit board, and the sensing end of the Hall element 31 is embedded in the Hall position 41 formed by stacking Y-plate silicon steel stator discs b422. In specific implementations, the Hall plate 3 can be fixed by bolts, screws, or other fastening methods.

[0051] On the other hand, since the upper frame 43 has jumpers wound with copper wires from the windings 45, and the copper wires extend to each winding 45; and the lower frame 44 has a Hall plate 3 fixed on it, the materials of both the upper and lower frames should meet the requirements of being non-conductive and having sufficient strength. In a preferred embodiment, the upper frame 43 and the lower frame 44 are made of insulating engineering plastic with a strength exceeding a specified value. The engineering plastic can fix the copper wires in the windings 45 and has insulation properties, which can prevent discharge between the copper wires and the stator; at the same time, the engineering plastic also has the advantages of being lightweight, easy to process and produce, and low in cost.

[0052] In this embodiment, the permanent magnet synchronous motor's cable is no longer led out through the rear end cover 17, but rather from the side of the fixed position of the Hall plate 3. For example... Figure 8 As shown, a cable tray 16 is provided on one side of the cavity flange 13 for leading out motor wires and encoder communication cables; Figure 8 In this embodiment, one of the cables on the Hall plate 3 is led out from the cable outlet 16 to the outer shell of the cavity flange 13 for connection with the externally located motor controller 32. The permanent magnet synchronous motor also includes a wire clamping block 15 and a waterproof gasket. The wire clamping block 15 and the waterproof gasket are fixed to the cavity flange 13 so that when the cable in the permanent magnet synchronous motor is led out through the cable outlet 16, the gap between the cable outlet 16 and the cable is sealed by the wire clamping block 15 and the waterproof gasket. In the permanent magnet synchronous motor provided in this embodiment, the cavity flange 13 used for fixing is a metal structure formed by extending 12 from the reducer housing. Its fixing strength is much greater than that of the plastic end caps in existing permanent magnet synchronous motors, thus avoiding problems such as cable displacement caused by insufficient fixing strength.

[0053] In practice, in order to further improve the heat dissipation performance of the permanent magnet synchronous motor, other heat dissipation structures or heat dissipation devices can be added to the above-mentioned permanent magnet synchronous motor structure.

[0054] As shown in Figure 9, each stator platter a 421 or stator platter b 422 has at least one set of recessed grooves 423 on its outer edge. The recessed grooves 423 extend in a direction parallel to the direction of the motor shaft 14. The recessed grooves 423 of all stator platter a 421 or stator platter b 422 in the stator platter group 42 are aligned to increase the heat dissipation surface area of ​​the outer edge of a single silicon steel stator platter and improve heat dissipation efficiency. Furthermore, additional heat dissipation devices can be added, which are fixed to the stator 4 through the recessed grooves 423 to further improve heat dissipation efficiency.

[0055] In the permanent magnet synchronous motor provided in this embodiment, the reducer 1 is a worm gear reducer. For example... Figure 10 As shown, the worm gear of the reducer 1 is integrally formed with the motor shaft 14 of the permanent magnet synchronous motor and is highly coaxial. The worm gear of the reducer 1 extends towards the stator 4 to form the motor shaft 14, and the rotor 2 is sleeved on the motor shaft 14. That is, the motor shaft 14 and the worm gear of the reducer 1 are integrally formed and highly coaxial. Figure 11 As shown, the rotor 2 of the permanent magnet synchronous motor is sleeved on the motor shaft 14. There are no bearings on the rear end cover 17. The motor shaft 14 is fixed by the bearings at both ends of the worm gear of the reducer 1. The bearings at both ends of the worm gear of the reducer 1 are enclosed inside the reducer by the reducer housing 11.

[0056] Furthermore, the worm gear of the reducer extends out of the reducer 1 through a bearing at the end away from the stator 4 and rotor 2. The bearing is provided with a keyway or flat protrusion at the end of the worm gear extending out of the reducer 1, so as to facilitate manual rotation of the reducer worm gear when the permanent magnet synchronous motor fails due to power failure. For example, by engaging the keyway with a socket wrench, the output shaft of the reducer can be manually rotated when the motor fails due to power failure, thereby manually controlling the mechanical equipment.

[0057] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A casingless permanent magnet synchronous motor, characterized in that: The motor includes a rear end cover, stator, Hall plate, rotor, and reducer. The rotor and stator are sequentially fitted onto the motor shaft from the inside out. The rear end cover seals the motor shaft inside the motor. Specifically, it includes: The stator includes a stator disk assembly, and one side of the stator disk assembly includes continuously arranged Hall positions; The Hall plate includes a circuit board and at least two Hall elements. The Hall elements are vertically inserted into the circuit board, which is fixed between the stator and the reducer. The Hall elements are housed in Hall positions to facilitate the routing of cables from the Hall plate through the side of the permanent magnet synchronous motor.

2. The casingless permanent magnet synchronous motor according to claim 1, characterized in that, The stator includes an upper frame, a lower frame, a stator platters, and at least one winding, specifically including: The stator disc assembly includes at least one stator disc a and at least one stator disc b. Stator disc a and stator disc b are stacked and assembled in layers and then pressed together. Stator disc b is close to the reducer. Among them, at least two consecutive Hall element slots are included between at least three adjacent windings on stator disk b, and the Hall element slots on all stator disk b are stacked to form a cavity-shaped Hall position, with the depth of the Hall position being greater than the height of the Hall element.

3. The casingless permanent magnet synchronous motor according to claim 2, characterized in that, The housing of the reducer extends toward the motor side to form a cavity flange, specifically including: The rear end cover, stator, and cavity flange are fastened together. The circuit board of the Hall plate is fixed on the lower frame of the stator and placed in the cavity flange.

4. The casingless permanent magnet synchronous motor according to claim 3, characterized in that, A cable outlet groove is provided on one side of the cavity flange, and the permanent magnet synchronous motor also includes a wire pressing block and a waterproof gasket, specifically including: The pressure block and waterproof gasket are fixed on the cavity flange so that when the cable in the permanent magnet synchronous motor is led out through the cable outlet slot, the pressure block and waterproof gasket seal the gap between the cable outlet slot and the cable.

5. The casingless permanent magnet synchronous motor according to claim 3, characterized in that, The permanent magnet synchronous motor also includes: O-rings are placed at the upper and lower frame positions to ensure a seal between the stator and the cavity flange, as well as between the stator and the rear end cover.

6. The casingless permanent magnet synchronous motor according to claim 2, characterized in that, Each of the stator disks a or b has at least one set of recessed grooves on its outer edge, specifically including: The recessed groove extends in a direction parallel to the motor shaft, and the recessed grooves of all stator discs a or b in the stator disc group are aligned.

7. The casingless permanent magnet synchronous motor according to claim 6, characterized in that, The permanent magnet synchronous motor also includes heat dissipation devices, specifically including: The heat dissipation device is fixed to the stator by an indented groove.

8. The casingless permanent magnet synchronous motor according to claim 2, characterized in that, The stator specifically includes: Stator disk a and stator disk b are silicon steel stator disks, and the silicon steel stator disks are coated with insulating varnish. The upper and lower skeletons are made of insulating engineering plastics with a strength exceeding the specified value.

9. The casingless permanent magnet synchronous motor according to claim 1, characterized in that, The reducer is a worm gear reducer, in which the worm gear and the motor shaft of the permanent magnet synchronous motor are integrally formed and highly coaxial. Specifically, it includes: The motor shaft is fixed by bearings at both ends of the reducer worm, and the bearings at both ends of the reducer worm are enclosed inside the reducer by the reducer housing.

10. The casingless permanent magnet synchronous motor according to claim 9, characterized in that, The permanent magnet synchronous motor also includes: The worm gear of the speed reducer exits the speed reducer through a bearing at the end away from the stator and rotor; The bearing has a keyway or flat protrusion at the end through which the worm gear of the reducer protrudes, so that the worm gear of the reducer can be manually rotated when the permanent magnet synchronous motor fails due to power failure.

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