A motor stator core

Abstract

The present invention relates to a motor stator core. The stator core is formed by nesting a ring-shaped grain-oriented silicon steel core and a ring-shaped non-grain-oriented silicon steel core disposed outside the ring-shaped grain-oriented silicon steel core. The ring-shaped grain-oriented silicon steel core is formed by stacking two kinds of grain-oriented silicon steel sheets. The ring-shaped grain-oriented silicon steel core is provided with orientation grooves. The orientation grooves and the ring-shaped non-grain-oriented silicon steel core are fitted to form closed grooves. A notch magnetic bridge is provided between the orientation grooves and the inner side wall of the ring-shaped grain-oriented silicon steel core. A magnetic bridge through hole is provided at the notch magnetic bridge, so that the magnetic path of the notch magnetic bridge is saturated. When in use, the magnetic bridge through hole of the present invention saturates the magnetic path of the notch magnetic bridge, thereby increasing the air-gap magnetic density, reducing the leakage magnetic coefficient, increasing the motor power density, and the dovetail groove can effectively reduce the notch leakage magnetic and the air-gap magnetic flux pulsation, and further increase the motor output torque.

Description

Technical Field

[0001] The present invention relates to the technical field of motors, and more particularly to a motor stator core, and more particularly to a stator core that combines oriented and non-oriented materials. Background Art

[0002] At present, non-oriented silicon steel sheets are used for the stators of electric vehicle motors, and the average motor efficiency ranges from 50% to 80%. Especially for high-speed motors, as the operating frequency increases, the core loss in the iron core increases significantly, which not only reduces the motor efficiency but also affects the long-term stable operation of the motor.

[0003] With the continuous improvement of the overall vehicle's driving range, new energy vehicle drive motors require high power density, high torque, high efficiency, wide high-efficiency range, and low loss. Using non-oriented silicon steel sheets as the motor core material cannot meet these requirements; due to the anisotropic characteristics of oriented silicon steel sheets, it makes it possible, but currently, the oriented technology is mainly applied to large hydro-generators and transformers, and there is no application in the field of new energy vehicle drive motors yet.

[0004] Therefore, there is an urgent need in the market for a stator core that combines oriented and non-oriented silicon steel to achieve the characteristics of high power density, low loss, etc. required for new energy vehicles. Summary of the Invention

[0005] The purpose of the present invention is to provide an improved motor stator core that can overcome the deficiencies of large power loss and low magnetic permeability in the prior art.

[0006] To achieve the above purpose, the technical solution of the present invention is: a motor stator core, characterized in that: the stator core is composed of a ring-shaped oriented silicon steel core and a ring-shaped non-oriented silicon steel core nested outside the ring-shaped oriented silicon steel core. The ring-shaped oriented silicon steel core serves as the stator teeth, and the ring-shaped non-oriented silicon steel core serves as the stator yoke. The ring-shaped oriented silicon steel core is formed by stacking two kinds of oriented silicon steel sheets. An orientation groove is provided on the ring-shaped oriented silicon steel core, and the orientation groove and the ring-shaped non-oriented silicon steel core are fitted together to form a closed groove. A slot mouth magnetic bridge is provided between the orientation groove and the inner side wall of the ring-shaped oriented silicon steel core, and a magnetic bridge through hole is provided at the slot mouth magnetic bridge to saturate the magnetic path of the slot mouth magnetic bridge.

[0007] Preferably, the ring-shaped oriented silicon steel core is formed by alternately stacking forward-oriented silicon steel sheets and reverse-oriented silicon steel sheets. The bottom of the orientation groove of the ring-shaped oriented silicon steel core is the orientation groove bottom yoke. A plurality of dovetail grooves are provided on the orientation groove bottom yoke, and each dovetail groove communicates with an orientation groove. The dovetail grooves form magnetic slot wedges at the slot mouth of the orientation groove. A clearance fit is formed between the orientation groove bottom yoke of the ring-shaped oriented silicon steel core and the inner wall of the ring-shaped non-oriented silicon steel core.

[0008] Furthermore, the two ends of the orientation slot are a large port and a small port respectively, the small port is connected to the slot magnetic bridge, the small port is arc-shaped or formed by multiple folded edges, and the shape of the small port corresponds to the side shape of the magnetic bridge through hole.

[0009] Furthermore, there are three magnetic bridge through holes, the middle one is a rectangular through hole, and the two side edges are quadrilateral through holes, and the angle of each folded edge matches the shape of the magnetic bridge through hole.

[0010] Compared with the prior art, the technical solution of the present invention not only improves the overall technical solution, but also includes many improvements in details. Specifically, it has the following beneficial effects:

[0011] 1. The improved scheme of the present invention is that the stator core is formed by nesting an annular oriented silicon steel core and an annular non-oriented silicon steel core arranged outside the annular oriented silicon steel core. By providing an orientation slot on the annular oriented silicon steel core and a magnetic bridge through hole, the magnetic circuit of the slot magnetic bridge is saturated, thereby increasing the air gap magnetic density, reducing the leakage magnetic coefficient, and improving the power density of the motor;

[0012] 2. In the technical solution of the present invention, the annular oriented silicon steel core is formed by staggered stacking of forward oriented silicon steel sheets and reverse oriented silicon steel sheets, which improves the axial flatness of the annular oriented silicon steel core and increases the uniformity, integrity and firmness of the oriented iron core;

[0013] 3. The yoke at the bottom of the orientation slot of the present invention is provided with a plurality of dovetail slots, which form magnetic slot wedges at the slot openings of the orientation slots. A clearance fit is formed between the yoke at the bottom of the orientation slot of the annular oriented silicon steel core and the inner wall of the annular non-oriented silicon steel core, which can effectively reduce the slot leakage magnetic flux and the air gap magnetic flux pulsation, thereby improving the motor output torque and efficiency and reducing the loss;

[0014] 4. The present invention has a simple structure, is easy to process, has a low cost, and is conducive to promotion and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a structural schematic diagram of the present invention.

[0016] Figure 2 It is a schematic structural diagram of a cross section of an embodiment of the present invention.

[0017] Figure 3 It is a schematic diagram of the structure of the annular oriented silicon steel core of the present invention.

[0018] Figure 4 This is a schematic diagram of the structure of the annular non-oriented silicon steel core of the present invention.

[0019] Figure 5 It is a partial enlarged schematic diagram of the present invention.

[0020] Figure 6 is Figure 5 a partially enlarged schematic view.

[0021] Figure 7 is a schematic view of the superposition structure of the forward-oriented silicon steel single sheet and the reverse-oriented silicon steel single sheet of the present invention.

[0022] Figure 8 is a comparison chart of the single-pole air-gap magnetic density curves of two kinds of stator cores in the embodiment of the present invention.

[0023] Figure 9 is a schematic view of the annular tooling structure of the present invention.

[0024] Reference numerals:

[0025] 1 annular non-oriented silicon steel core, 2 annular oriented silicon steel core, 3 magnetic bridge through-hole, 4 orientation groove, 5 annular tooling;

[0026] 11 dovetail groove;

[0027] 21 forward-oriented silicon steel single sheet, 22 reverse-oriented silicon steel single sheet;

[0028] 211 stator tooth part, 212 orientation groove bottom yoke part, 213 slot opening magnetic bridge;

[0029] 51 base, 52 positioning pin. Detailed implementation manners

[0030] Next, the technical solution of the present invention will be clearly and completely described in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0031] The present invention provides a motor stator core. Specifically, refer to Figure 1 , and its difference from the prior art is that: the stator core is nested by an annular oriented silicon steel core 2 and an annular non-oriented silicon steel core 1 arranged outside the annular oriented silicon steel core. The annular oriented silicon steel core serves as the stator tooth part, and the annular non-oriented silicon steel core serves as the stator yoke part. The annular oriented silicon steel core is composed of two kinds of oriented silicon steel sheets superimposed. There is an orientation groove 4 on the annular oriented silicon steel core. The orientation groove and the annular non-oriented silicon steel core are fitted to form a closed groove. There is a slot opening magnetic bridge 213 between the orientation groove and the inner side wall of the annular oriented silicon steel core. There is a magnetic bridge through-hole 3 at the slot opening magnetic bridge, so that the magnetic path of the slot opening magnetic bridge is saturated, hindering the magnetic force lines of the tooth part from entering the slot opening oriented steel strip. The width of the yoke part steel strip at the slot opening has sufficient strength guarantee after removing the through-hole; in addition, due to the low magnetic permeability in the tangential direction of the oriented silicon steel, it further causes local saturation at the through-hole, achieving the reduction of magnetic leakage and the improvement of the magnetic energy product in the main magnetic path.

[0032] Specifically, the characteristics of grain-oriented silicon steel are that the iron loss of the grain-oriented steel strip in the rolling direction is only 1 / 3 of that in the transverse direction, the ratio of magnetic permeability is 6:1, its iron loss is about 1 / 2 of that of the hot-rolled strip, and the magnetic permeability is 2.5 times that of the hot-rolled strip. Therefore, using grain-oriented steel for the motor core can improve the output torque and efficiency of the motor to a certain extent. However, the problem with grain-oriented silicon steel is that the magnetic permeability in the tangential direction is lower than that of traditional non-oriented silicon steel, with larger iron loss and higher iron consumption. Therefore, the present invention considers combining two different silicon steel materials to make a specific motor stator core. This combination not only needs to consider the process, but also improve the magnetic permeability, reduce magnetic leakage and magnetic loss in terms of structure.

[0033] In one embodiment, the annular grain-oriented silicon steel core is formed by alternately stacking and bonding positive grain-oriented silicon steel sheets 21 and reverse grain-oriented silicon steel sheets 22 to form a ring structure. It is also possible to stack two positive grain-oriented silicon steel sheets and one reverse grain-oriented silicon steel sheet in such a way that the number of positive grain-oriented silicon steel sheets is twice the number of reverse grain-oriented silicon steel sheets. The magnetic permeability of grain-oriented silicon steel is the highest in the rolling direction. Within the range of ±20° in the rolling direction, its performance is far superior to that of non-oriented silicon steel in terms of magnetic characteristics. Based on this special effect, a single tooth of grain-oriented silicon steel forms a unit, which improves the material utilization rate of the grain-oriented silicon steel sheet and further gives full play to the optimal characteristics of grain-oriented silicon steel.

[0034] The bottom of the orientation groove of the annular grain-oriented silicon steel core is the orientation groove bottom yoke part. The orientation groove bottom yoke part is provided with a plurality of dovetail grooves 11, and each dovetail groove communicates with an orientation groove. The dovetail groove forms a magnetic groove wedge at the notch of the orientation groove 4. A clearance fit is formed between the orientation groove bottom yoke part of the annular grain-oriented silicon steel core and the inner wall of the annular non-oriented silicon steel core. Specifically, the dovetail groove is arranged at the central axis position of the orientation groove. Since the dovetail groove is equivalent to placing a magnetic groove wedge at the notch of the orientation groove, it can effectively reduce the notch magnetic leakage and air-gap flux pulsation, thereby improving the output torque and efficiency of the motor and reducing the loss. Specifically, the two ends of the orientation groove are a large port and a small port respectively. The small port is connected to the notch magnetic bridge. The small port is arc-shaped and corresponds to the side shape of the magnetic bridge through hole, so as to increase the magnetic resistance of the notch magnetic bridge. The magnetic bridge through hole here adopts a square hole, a circular hole or a quadrilateral hole.

[0035] The dovetail groove here connects the annular non-oriented silicon steel core 1 and the annular grain-oriented silicon steel core 2, which is convenient for the stator to wind the wire. The dovetail groove structure is trapezoidal, which is convenient for placing a trapezoidal groove wedge to fix during the wire winding process to prevent loosening during winding.

[0036] In another embodiment, to achieve a higher salient pole ratio for the drive motor, when designing the drive motor, grain-oriented silicon steel laminations with higher magnetic permeability are used instead of non-oriented silicon steel laminations in the rotor polarization direction. At the same time, grain-oriented silicon steel laminations are also used for the stator pole shoes, effectively reducing the iron loss and increasing the salient pole ratio of the motor.

[0037] The teeth of the motor stator are made of annular laminated oriented silicon steel sheets, and the layers are bonded with epoxy glue to ensure the firmness of the annular core. The yoke of the motor stator is made of non-oriented silicon steel sheets, and a dovetail groove is left on the inner side of the annular steel belt. The dovetail groove and the oriented annular core are matched with a small gap. The stator magnetic circuit is in an annular selective motion state and is non-directional in the stator yoke. The use of non-oriented silicon steel is conducive to giving full play to the isotropic characteristics of non-oriented electrical steel.

[0038] The two ends of the orientation slot are a large port and a small port respectively. The small port is connected to the slot magnetic bridge. The small port is formed by a plurality of folded edges. The shape of the small port corresponds to the side shape of the magnetic bridge through hole. There are three magnetic bridge through holes, the middle one is a rectangular through hole, and the two sides are quadrilateral through holes. The angle of each folded edge matches the shape of the magnetic bridge through hole. The three through holes are evenly arranged along the slot magnetic bridge, which is conducive to the saturation of the magnetic bridge, saturating the magnetic field around the through hole, and hindering the magnetic lines of force of the tooth from entering the slot oriented steel strip. The width of the steel strip of the yoke of the slot has sufficient strength after removing the through hole; in addition, due to the low magnetic permeability of the oriented silicon steel in the tangential direction, it further leads to local saturation at the through hole, thereby reducing leakage magnetic flux and increasing the magnetic energy product in the main magnetic circuit.

[0039] At the same time, the yoke at the bottom of the orientation groove is provided with an inwardly concave arc surface, and the connection between the yoke at the bottom of the orientation groove and the dovetail groove is provided with an arc chamfer. The large end of the orientation groove is connected to the dovetail groove, and the width of the dovetail groove is 0.2-0.4 times the width of the large end of the orientation groove.

[0040] In another specific embodiment, the annular oriented silicon steel core is formed by stacking single oriented silicon steel sheets in opposite directions, which improves material utilization and gives full play to the advantage of higher magnetic permeability in the rolling direction. It is also beneficial to ensure axial flatness and increase the uniformity, integrity and firmness of the oriented core. In addition, the sheets are bonded together with epoxy glue to increase the firmness of the core.

[0041] Specifically, for the single-piece design of oriented silicon steel, the width of the yoke at the bottom of the oriented slot must meet sufficient mechanical strength, and a small gap must be formed with the non-oriented silicon steel core to reduce the large stress generated between the two punching sheets, which may lead to a decrease in the performance of the silicon steel sheet. The magnetic bridge design at the slot mouth must ensure mechanical strength, and the magnetic slot wedge and oriented silicon steel must be integrated into an integrated design to reduce magnetic leakage at the tooth, reduce magnetic flux pulsation in the air gap, and improve motor performance.

[0042] The oriented silicon steel sheets are stacked in a circular pattern, the slot magnetic bridge holes are in regular shape, and the holes are designed to be circular tooling (see Figure 9 ) The annular tooling consists of a base and a locating pin. The shape of the locating pin is consistent with the orientation groove, ensuring that there is no dimensional deviation during the assembly of the electrical steel. Single-piece stacking can ensure the concentricity of the entire annular core and improve the axial and radial flatness and roughness of the entire core.

[0043] Specifically, the ring-oriented silicon steel core is formed by alternately stacking forward-oriented silicon steel sheets and reverse-oriented silicon steel sheets on a ring-shaped tooling. The ring-shaped tooling includes a base and positioning pins provided on the base. The base is in a circular ring shape, and the positioning pins are arranged in pairs around the circular ring-shaped base. The distance between adjacent pairs of positioning pins is matched with the size of the orientation groove. Further, when the positioning pins are arranged in pairs, the positioning pins in each pair can be arranged in parallel, or there can be an included angle between the two positioning pins, which is beneficial to making the ring-oriented silicon steel core more stable and maintaining firmness and stability.

[0044] When the traditional non-oriented stator core and the stator core of the present invention operate under no-load conditions, the air-gap sinusoidality of the whole machine made of the stator core of the present invention is significantly better than that of the motor made of the traditional open-slot non-oriented stator core. Figure 9 The results show that the average value of the air-gap magnetic density of the new motor is 0.6713 T, which is higher than the average air-gap magnetic density of the traditional motor; the content of each harmonic in the air gap decreases significantly, and the fundamental wave amplitude increases significantly, which is beneficial to improving the output and efficiency of the motor, reducing the motor loss, and significantly improving the performance of the motor in all directions.

[0045] The above content is a further detailed description of the present invention in combination with specific preferred embodiments. It cannot be determined that the specific implementation of the present invention is only limited to the above descriptions. For those of ordinary skill in the technical field to which the present invention pertains, without departing from the concept of the present invention, several simple deductions or substitutions can be made, and all should be regarded as belonging to the protection scope of the present invention.

Claims

1. A motor stator core, characterized in that: The stator core is formed by nesting a ring-shaped grain-oriented silicon steel core and a ring-shaped non-grain-oriented silicon steel core arranged outside the ring-shaped grain-oriented silicon steel core. The ring-shaped grain-oriented silicon steel core serves as the stator tooth part, and the ring-shaped non-grain-oriented silicon steel core serves as the stator yoke part. The ring-shaped grain-oriented silicon steel core is formed by stacking two types of grain-oriented silicon steel sheets. An orientation groove is provided on the ring-shaped grain-oriented silicon steel core. The orientation groove and the ring-shaped non-grain-oriented silicon steel core are fitted together to form a closed groove. A notch magnetic bridge is provided between the orientation groove and the inner side wall of the ring-shaped grain-oriented silicon steel core. A magnetic bridge through-hole is provided at the notch magnetic bridge, so that the magnetic circuit of the notch magnetic bridge is saturated; The ring-shaped grain-oriented silicon steel core is stacked in a manner of two positive grain-oriented silicon steel sheets and one reverse grain-oriented silicon steel sheet, so that the number of positive grain-oriented silicon steel sheets is twice the number of reverse grain-oriented silicon steel sheets; the bottom of the orientation groove of the grain-oriented silicon steel core is the yoke part of the orientation groove bottom. A number of dovetail grooves are provided on the yoke part of the orientation groove bottom. Each dovetail groove communicates with an orientation groove. The dovetail grooves are arranged at the central axis position of the orientation groove. A clearance fit is formed between the yoke part of the orientation groove bottom of the ring-shaped grain-oriented silicon steel core and the inner wall of the ring-shaped non-grain-oriented silicon steel core. The dovetail grooves form magnetic slot wedges at the notch of the orientation groove; the two ends of the orientation groove are respectively a large port and a small port. The large port of the orientation groove communicates with the dovetail groove. The width of the dovetail groove is 0.2 - 0.4 times the width of the large port of the orientation groove; The ring-shaped grain-oriented silicon steel core is formed by alternately stacking positive grain-oriented silicon steel sheets and reverse grain-oriented silicon steel sheets on a ring-shaped tooling. The ring-shaped tooling includes a base and positioning pins arranged on the base. The base is in a ring shape. The positioning pins are grouped in pairs and arranged around the ring-shaped base. The distance between adjacent pairs of positioning pins is matched with the size of the orientation groove.

2. The stator core of an electric machine according to claim 1, characterized in that: The small port of the orientation groove is connected to the notch magnetic bridge. The small port is in an arc shape or formed by a plurality of folded edges connected in series. The shape of the small port corresponds to the side shape of the magnetic bridge through-hole, so as to increase the magnetic resistance of the notch magnetic bridge.

3. The stator core of an electric machine according to claim 2, wherein: There are three magnetic bridge through-holes in total. The middle one is a rectangular through-hole, and the two side ones are quadrilateral through-holes. The angle of each folded edge is matched with the outer shape of the magnetic bridge through-hole.

4. The stator core of an electric machine according to claim 2, characterized in that: The magnetic bridge through-hole is a circular hole or a quadrilateral hole.

5. A motor stator core according to claim 1, characterized in that: The yoke part of the orientation groove bottom is provided with an inward concave arc surface. A circular arc chamfer is provided at the connection between the yoke part of the orientation groove bottom and the dovetail groove.

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