Solid rotor core, rotor assembly and motor

Abstract

The utility model provides a solid rotor core, a rotor assembly and a motor, the solid rotor core comprises an iron core body, the outer circumferential wall of the iron core body is provided with a plurality of annular grooves arranged at intervals along the axial direction of the iron core body, the depth of each annular groove is b, the depth b of a fundamental wave magnetic flux generated in the operation process of a motor applying the iron core body into the outer circumferential wall of the iron core body is larger than or equal to 7% and smaller than 7%. According to the solid rotor iron core, a harmonic eddy current loop is effectively cut off on the outer circumferential wall of the iron core body without hindering closed-loop flow of fundamental wave eddy current in the iron core body, so that the harmonic eddy current loss of the solid rotor iron core is greatly reduced, the efficiency and mechanical characteristics of a solid rotor motor are improved, and the service life of the solid rotor motor is prolonged. And popularization and application of the solid rotor iron core in the industry are facilitated.

Description

Technical Field

[0001] The utility model belongs to the technical field of motor design, and in particular relates to a solid rotor core, a rotor assembly and a motor. Background Art

[0002] The operating principle of a solid rotor induction motor is the same as that of a conventional induction motor. When current flows through the motor's multiphase stator windings, a synthetic rotating magnetic field is generated, generating an induced electromotive force and current in the solid rotor. These interactions produce electromagnetic force and torque, causing the rotor to rotate, thereby converting electrical energy into mechanical energy. The stator structure of a solid rotor induction motor is the same as that of a conventional induction motor, while the rotor is a solid ferromagnetic cylinder. It serves as both the core of the magnetic circuit and the winding of the circuit, combining the two into one. This is the key difference between solid rotor induction motors and conventional induction motors.

[0003] Solid rotors offer a simple structure, high mechanical strength, and excellent balance, making them suitable for frequent heavy-load starts or prolonged braking. However, solid rotors also have significant drawbacks, significantly impacting their application and development. On the one hand, high rotor losses result in low motor efficiency, which in turn leads to weaker mechanical characteristics and high slip under rated operating conditions. On the other hand, the harmonic magnetic flux penetrates the rotor surface only shallowly, but the eddy current losses caused by these harmonic magnetic fluxes are high, resulting in low motor efficiency and severely hindering the promotion and application of this type of motor.

[0004] In order to at least partially solve the above-mentioned deficiencies in the prior art, the present utility model is proposed. Utility Model Content

[0005] Therefore, the utility model provides a solid rotor core, a rotor assembly and a motor, which can solve the technical problem in the prior art that the solid rotor core has large eddy current losses caused by harmonic magnetic flux, resulting in low efficiency of the motor, which seriously affects the promotion and application of this type of motor.

[0006] In order to solve the above problems, the present invention provides a solid rotor core, including an iron core body, wherein the outer circumferential wall of the iron core body is configured with a plurality of annular grooves spaced along its axial direction, the depth of the annular grooves being b, and the depth of the fundamental wave magnetic flux generated in the motor used in the iron core body during operation penetrating into the outer circumferential wall of the iron core body is △, and 7% △≤b<△.

[0007] In some embodiments, Where ρ is the rotor resistivity, s is the slip rate, μ0 is the magnetic permeability of the vacuum material, μ1 is the magnetic permeability of the rotor core material, and ω is the power supply angular frequency.

[0008] In some embodiments, the width of each annular groove is a, 0<a<b.

[0009] In some embodiments, the core body is further configured with a plurality of ventilation holes penetrating through both axial ends thereof.

[0010] The utility model also provides a rotor assembly, comprising the above-mentioned solid rotor core, wherein a rotating shaft is inserted into the rotating shaft hole of the solid rotor core.

[0011] In some embodiments, the rotating shaft and the rotating shaft hole are interference fit.

[0012] In some embodiments, conductive and non-magnetic end rings are respectively provided at both ends of the core body, and the radial ring width of the conductive and non-magnetic end rings is c, where c>Δ.

[0013] In some embodiments, when ventilation holes are configured on the core body, the inner ring wall of the conductive and non-magnetic end ring is located radially outside each of the ventilation holes.

[0014] In some embodiments, the conductive and non-magnetic end rings are welded to the core body.

[0015] The utility model also provides a motor, comprising the above-mentioned rotor assembly.

[0016] The solid rotor core, rotor assembly and motor provided by the utility model have the following beneficial effects:

[0017] By providing an annular groove arranged along the circumferential direction on the outer circumferential wall of the core body and limiting the depth b of the annular groove, the depth b of the annular groove is not greater than the fundamental magnetic flux penetration depth, i.e., the aforementioned Δ, and not less than the harmonic magnetic flux penetration depth region, i.e., the aforementioned 7% Δ, thereby effectively cutting off the harmonic eddy current circuit on the outer circumferential wall of the core body while not hindering the closed-loop flow of the fundamental eddy current in the core body. In this way, the harmonic eddy current loss (i.e., the additional loss) of the solid rotor core is greatly reduced, which improves the efficiency and mechanical properties of the solid rotor motor (i.e., overcomes the deficiency of the relatively soft mechanical properties of the solid rotor motor in the prior art), and is conducive to the promotion and application of the solid rotor core in the industry;

[0018] a<b can minimize the adverse effects on the stator and rotor air gap width, ensuring that the magnetic flux density of the radial air gap is at a high level;

[0019] Conductive and non-magnetic end rings are respectively provided at both axial ends of the core body, so that the reactance at the ends of the core body is greatly reduced, which is equivalent to reducing the end coefficient, thereby reducing the impedance of the solid rotor, improving the power density and force energy index of the motor, and making c>△, which can ensure that most of the eddy currents generated by the fundamental wave magnetic flux of the solid rotor are closed through the conductive and non-magnetic end rings. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following is a brief introduction to the drawings required for the embodiments or the description of the prior art. The drawings described below are merely exemplary. For those skilled in the art, other implementation drawings can be derived from the provided drawings without inventive effort.

[0021] Figure 1 1 is a schematic diagram of the three-dimensional structure of the solid rotor core of an embodiment of the present invention (partial cross-section);

[0022] Figure 2 This is a schematic diagram of the three-dimensional structure of the rotor assembly of an embodiment of the present utility model;

[0023] Figure 3 yes Figure 2 Side view of

[0024] Figure 4 yes Figure 3 Left view of;

[0025] Figure 5 This is a schematic diagram of a simulation of the flow path of harmonic eddy currents in a solid rotor core according to an embodiment of the present invention;

[0026] Figure 6 This is a schematic diagram of a simulation of the flow path of the fundamental eddy current in the solid rotor core of an embodiment of the present invention;

[0027] Figure 7 It is a schematic diagram of the three-dimensional structure of a rotor assembly according to another embodiment of the present invention;

[0028] Figure 8 This is a schematic diagram of the three-dimensional structure of the motor according to an embodiment of the present utility model;

[0029] Figure 9 yes Figure 8 A schematic diagram of a three-dimensional structure of a motor after partial cross-section;

[0030] Figure 10 When a<b, the simulation diagram of the air gap magnetic flux in the stator and rotor air gap shows that the maximum value of the air gap magnetic flux is 0.5610T.

[0031] Figure 11 When a>b, the simulation diagram of the air gap magnetic flux in the stator and rotor air gap shows that the maximum value of the air gap magnetic flux is 0.4538T.

[0032] The accompanying drawings are:

[0033] 1. Core body; 11. Ring groove; 12. Ventilation hole; 13. Rotating shaft hole; 2. Rotating shaft; 3. Conductive and non-magnetic end rings; 4. Stator assembly; 41. Stator core; 42. Stator winding; 5. End cover; 51. Threaded fastener; 6. Bearing. DETAILED DESCRIPTION

[0034] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is in no way intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0035] In the description of the present invention, it needs to be understood that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "horizontal, vertical, vertical, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the drawings. They are only for the convenience of describing the present invention and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the device or element referred to must have a specific direction or be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the scope of protection of the present invention; the directional words "inside and outside" refer to the inside and outside relative to the outline of each component itself.

[0036] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used herein to describe the spatial positional relationship of a device or feature to other devices or features as shown in the figures. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figures. For example, if the device in the drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90° or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0037] In addition, it should be noted that the use of words such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. Unless otherwise stated, the above words have no special meaning and therefore cannot be understood as limiting the scope of protection of this utility model.

[0038] See also Figure 1 and Figure 11 As shown, according to an embodiment of the present invention, a solid rotor core is provided, including a core body 1 (made of ferromagnetic material), and a plurality of annular grooves 11 are constructed on the outer circumferential wall of the core body 1 and arranged at intervals along its axial direction. The depth of the annular grooves 11 is b, and the depth of the fundamental magnetic flux generated by the motor used in the core body 1 during operation penetrating into the outer circumferential wall of the core body 1 is △, 7%△≤b<△. It can be understood that the aforementioned depth △ is objectively a relatively determined parameter after the specifications and models of the motor used in the core body 1 are determined. According to research, the total harmonic distortion rate of the total harmonic content as a percentage of the fundamental content is generally less than 7%. When b is not less than 7%△, most of the harmonic eddy currents can be effectively cut off.

[0039] In this technical solution, an annular groove 11 is provided on the outer circumferential wall of the core body 1 along its circumferential direction, and the depth b of the annular groove 11 is limited so that the depth b of the annular groove 11 is not greater than the fundamental magnetic flux penetration depth, i.e., the aforementioned △, and is not less than the harmonic magnetic flux penetration depth area, i.e., the aforementioned 7% △. This effectively cuts off the harmonic eddy current circuit on the outer circumferential wall of the core body 1 while not hindering the closed-loop flow of the fundamental eddy current in the core body 1. In this way, the harmonic eddy current loss (i.e., additional loss) of the solid rotor core is greatly reduced, which improves the efficiency and mechanical properties of the solid rotor motor (i.e., overcomes the deficiency of the solid rotor motor in the prior art that the mechanical properties are relatively soft), which is conducive to the promotion and application of the solid rotor core in the industry.

[0040] In a preferred embodiment, the annular grooves 11 are evenly spaced apart along the axial direction of the core body 1 , which can simplify the machining process of forming the annular grooves 11 on the outer circumferential wall of the core body 1 by machining.

[0041] The above △ can be obtained by finite element simulation or according to the formula The preferred method is to use the formula Here, ρ is the rotor resistivity, expressed in Ω·m; s is the slip, a dimensionless percentage; μ0 is the magnetic permeability of the vacuum material, expressed in H / m; μ1 is the magnetic permeability of the rotor core material, expressed in H / m; and ω is the power supply angular frequency, expressed in rad / s. Thus, using the above formula, once the rotor core material selection and motor design performance are determined, the design range of the annular groove 11 depth can be further determined, thereby simplifying the process of selecting the design parameters for the annular groove 11 for a specific rotor core.

[0042] Specifically, when s=1, that is, the penetration depth △ value is the smallest during startup, and when running at a small slip rate, the △ value is larger. For the fundamental magnetic flux (magnetic field), since the penetration depth of the magnetic flux is large, most of the fundamental magnetic flux will pass through the convex portion between the two adjacent annular grooves 11 and penetrate into the inner side of the annular groove 11, ensuring that the additional loss caused by the harmonic eddy current is reduced while the effective output force energy index of the motor is not affected, thereby improving the efficiency of the motor.

[0043] In a specific embodiment, the value of b ranges from 0.01 to 0.015 cm.

[0044] In some embodiments, the width of each annular groove 11 is a, 0<a<b, that is, the axial width of each annular groove 11 should be smaller than its depth, so as to minimize the adverse effect on the stator and rotor air gap width. If a>b, it is equivalent to a relative increase in the radial air gap between the stator and rotor of the motor. The air gap is the core of the motor energy conversion. The larger the air gap, the lower the motor efficiency. For example, the simulation comparison data of a certain motor can be found in the following table. Figure 10 and Figure 11 As shown in FIG, when a<b, the maximum radial air gap magnetic flux density is a higher 0.5610T, while when a>b, the maximum radial air gap magnetic flux density is a lower 0.4538T.

[0045] In some embodiments, the core body 1 is further constructed with a plurality of ventilation holes 12 passing through both axial ends thereof, so as to effectively cool and dissipate the heat of the core body 1 during operation, thereby preventing the motor temperature from rising excessively.

[0046] See Figures 2 to 7 As shown, according to an embodiment of the present invention, a rotor assembly is further provided, comprising the aforementioned solid rotor core. A rotating shaft 2 is inserted into a rotating shaft hole 13 of the solid rotor core to output torque. In a specific embodiment, the rotating shaft 2 and the rotating shaft hole 13 are interference-fitted. The interference fit is achieved by press-fitting, a mature process that is relatively easy to implement.

[0047] In some embodiments, conductive and non-magnetic end rings 3 are respectively provided at both ends of the core body 1, and the radial ring width of the conductive and non-magnetic end rings 3 is c, c>△. Specifically, the material of the conductive and non-magnetic end rings 3 can be a good conductor of non-ferromagnetic materials, such as copper, aluminum, gold, silver, etc., and copper or aluminum can be used based on cost considerations.

[0048] In this technical solution, conductive and non-magnetic end rings 3 are respectively provided at both axial ends of the core body 1, so that the reactance at the ends of the core body 1 is greatly reduced, which is equivalent to reducing the end coefficient, thereby reducing the impedance of the solid rotor, improving the power density and force energy index of the motor, and making c>△, which can ensure that most of the eddy currents generated by the fundamental wave magnetic flux of the solid rotor are closed through the conductive and non-magnetic end rings 3.

[0049] When ventilation holes 12 are constructed on the core body 1, the inner ring wall of the conductive and non-magnetic end ring 3 is located radially outside each ventilation hole 12. This can reduce the difficulty of structural design of the conductive and non-magnetic end ring 3, thereby reducing manufacturing costs, that is, there is no need to set and process the structure corresponding to the ventilation hole 12 thereon.

[0050] In a preferred embodiment, the conductive non-magnetic end ring 3 is welded to the core body 1, which can ensure good electrical contact between the conductive non-magnetic end ring 3 and the core body 1, ensuring the smooth flow of fundamental eddy current while improving the structural installation reliability of the rotor core. In a specific embodiment, the conductive non-magnetic end ring 3 and the core body 1 are connected by fusion welding.

[0051] The solid rotor core can be manufactured by machining or die-casting, and the conductive and non-magnetic end rings 3 can also be manufactured by machining or die-casting.

[0052] According to an embodiment of the present invention, a motor is also provided, comprising the above-mentioned rotor assembly. Figure 8 and Figure 9 As shown, the motor also includes a stator assembly 4 and end caps 5 at both ends of the stator assembly 4. The stator assembly 4 includes a stator core 41 (which is formed by press-fitting multiple silicon steel sheets) and stator windings 42 wound around the stator teeth of the stator core 41. The outer side of the stator core 41 is overmolded with an insulation layer, and the stator windings 42 are wound outside the insulation layer. The stator assembly 4 is sleeved on the outer side of the rotor assembly via the stator core 41. The ends of the rotating shaft 2 in the rotor assembly are supported on two end caps 5 by bearings 6. The end caps 5 at both ends axially clamp the stator core 41 via threaded fasteners 51. When current is passed through the stator winding 42, a synthetic rotating magnetic field is generated, generating an induced electromotive force and current in the solid rotor core. The interaction generates electromagnetic force and electromagnetic torque, causing the rotor assembly to rotate.

[0053] The following is a detailed description of the assembly process of the motor of the present invention:

[0054] Step 1: Using a dedicated stamping die, silicon steel sheets with excellent magnetic conductivity are laminated into a specific stator core (i.e., the aforementioned stator core 41, the same below). The stator core is then insulated with plastic wrap. A stator winding with a specific number of turns (i.e., the aforementioned stator winding 42, the same below) is then wound onto the stator core insulation material layer. The stator winding material is preferably enameled copper wire or enameled aluminum wire, thereby completing the stator production.

[0055] Step 2: Using a dedicated die-casting mold, die-casting a solid rotor core of a specific shape and size. Alternatively, a CNC machine tool can be used to precision-turn a solid rotor core of a specific shape (also referred to as the aforementioned solid rotor core, the same below). The solid rotor core is preferably made of a ferromagnetic material with excellent magnetic conductivity.

[0056] Step 3: Use a dedicated die-casting mold to die-cast end rings of specific shape and size (i.e., the aforementioned conductive and non-magnetic end rings 3, the same below), and then weld the core body 1 to the end rings. The end rings should have good electrical contact with the rotor core and possess a certain mechanical strength. The end rings are preferably made of non-magnetic materials with excellent conductive properties, such as aluminum, copper, etc.

[0057] Step 4: Use a hydraulic press to press the rotating shaft (also referred to as the rotating shaft 2, similarly hereinafter) into the solid rotor shaft hole (also referred to as the rotating shaft hole 13) to complete the rotor assembly.

[0058] Step 5: Assemble and tighten the stator assembly, rotor assembly, end cover, fastening screws (i.e. the aforementioned threaded fasteners 51 ), bearings and other components in a specific order to complete the production of the solid rotor motor.

[0059] It is easy for those skilled in the art to understand that, under the premise of no conflict, the advantageous technical features of the above-mentioned methods can be freely combined and superimposed.

[0060] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principles of the present invention shall be included in the scope of protection of the present invention. The above description is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and variations can be made without departing from the technical principles of the present invention. Such improvements and variations shall also be considered within the scope of protection of the present invention.

Claims

1. A solid rotor core, characterized in that: The invention comprises an iron core body (1), wherein the outer circumferential wall of the iron core body (1) is provided with a plurality of annular grooves (11) spaced apart along the axial direction thereof, the depth of the annular grooves (11) being b, the depth of the fundamental wave magnetic flux generated in the motor used in the iron core body (1) during operation penetrating into the outer circumferential wall of the iron core body (1) being △, and 7% △≤b<△.

2. The solid rotor core according to claim 1, characterized in that: Where ρ is the rotor resistivity, s is the slip rate, μ0 is the magnetic permeability of the vacuum material, μ1 is the magnetic permeability of the rotor core material, and ω is the power supply angular frequency.

3. The solid rotor core according to claim 1, wherein: The groove width of each annular groove (11) is a, 0<a<b.

4. The solid rotor core according to claim 3, characterized in that: The iron core body (1) is also provided with a plurality of ventilation holes (12) penetrating through both axial ends thereof.

5. A rotor assembly, characterized in that: The solid rotor core comprises the solid rotor core according to any one of claims 1 to 4, wherein a rotating shaft (2) is inserted into a rotating shaft hole (13) of the solid rotor core.

6. The rotor assembly according to claim 5, wherein: The rotating shaft (2) and the rotating shaft hole (13) are interference-fitted.

7. The rotor assembly according to claim 5, wherein: Both ends of the iron core body (1) are respectively provided with conductive and non-magnetic end rings (3), and the radial ring width of the conductive and non-magnetic end rings (3) is c, where c>Δ.

8. The rotor assembly according to claim 7, wherein: When ventilation holes (12) are configured on the core body (1), the inner ring wall of the conductive and non-magnetic end ring (3) is located radially outside each ventilation hole (12).

9. The rotor assembly according to claim 7, wherein: The conductive and non-magnetic end ring (3) is welded to the iron core body (1).

10. A motor, characterized in that: A rotor assembly comprising any one of claims 5 to 9.

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