Rotor and EPS motor

Abstract

The utility model belongs to the technical field of automobile steering systems, and discloses a rotor and an EPS motor. The rotor comprises a cylindrical rotor core body, slotted holes are formed in the rotor core body, magnetic steel sheets are inserted into the slotted holes, the rotor core body is connected in sequence, a protruding part is formed on the outer wall of the rotor core body, and the outer surface of the protruding part is in an arc shape; the rotor core bodies are in butt joint in the axial direction, and the protruding parts are staggered with one another. The problem that in the prior art, higher harmonics of an EPS motor are too large, and consequently working noise of the EPS motor is too high is solved.

Description

Technical Field

[0001] The utility model relates to the technical field of automobile steering systems, in particular to a rotor and an EPS motor. Background Art

[0002] With the development of new energy vehicles and intelligent driving industries, the electrification of automobile steering systems has become a technological development trend, and electric power steering systems require the use of EPS motors.

[0003] Since the EPS motor is connected to the steering wheel through mechanical components, when the EPS motor vibrates and generates noise, the noise will be transmitted to the steering wheel through the mechanical components, causing the driver to clearly feel the noise and vibration. Analysis shows that when the EPS motor generates loud noise, the higher harmonics of the EPS motor will become significantly larger. The EPS motor is provided with a stator and a rotor, and an air gap is formed between the rotor and the stator. The air gap will affect the magnetic flux of the rotor. Under the prior art, since the rotor is a cylinder, the air gap is annular, and the two sides of the air gap are arc-shaped, this causes the magnetic flux of the rotor to be close to a horizontal state at the peak and trough positions, and the magnetic flux fluctuation of the rotor is close to a trapezoid when observed from the coordinate system, and the rotor magnetic density is correlated with the stator's back electromotive force, causing the stator's back electromotive force fluctuation to be close to a trapezoid, resulting in an increase in the higher harmonics of the EPS motor, which in turn causes the EPS motor to be excessively noisy. Utility Model Content

[0004] The utility model aims to provide a rotor and an EPS motor to solve the problem that the EPS motor has excessively large high-order harmonics and causes excessively high operating noise in the EPS motor under the prior art.

[0005] To achieve this purpose, the utility model adopts the following technical solution: the utility model provides a rotor, including a rotor core, which is cylindrical, with slots opened inside the rotor core, magnetic steel sheets inserted into the slots, the rotor cores are connected in sequence, and a protrusion is formed on the outer wall of the rotor core, and the outer surface of the protrusion is arc-shaped; the rotor cores are butt-jointed along the axial direction, and the protrusions are staggered with each other.

[0006] Preferably, the slot is circumferentially opened near the edge of the rotor core, the slot is in a straight line shape, the length direction of the slot is perpendicular to the radial direction of the rotor core, and the magnetic steel sheet is embedded in the slot.

[0007] Preferably, the radius of the protrusion is r1, the radius of the rotor core is r2, the distance between the protrusion and the center of the circle is r3, and r3+r1>r2.

[0008] Preferably, the protrusions are distributed at equal intervals in the circumferential direction of the rotor core, and the protrusions correspond to the slots one by one.

[0009] Preferably, perpendicular to the axial direction of the rotor, the protrusions on the rotor core are distributed in a stepped manner.

[0010] Preferably, perpendicular to the axial direction of the rotor, the protrusions on the rotor core are distributed in a W-shape.

[0011] Preferably, a weight-reducing hole is opened in the rotor core along the axial direction of the rotor core.

[0012] An EPS motor comprises the rotor described above and a stator, wherein the rotor is inserted into the stator.

[0013] Beneficial effect: By providing a protrusion on the rotor core, when the rotor core rotates in the stator, the spacing of the air gap between the stator and the rotor is changed, thereby changing the peak and trough values ​​of the rotor magnetic flux density to be closer to a parabola shape, which makes the rotor magnetic flux density fluctuation closer to a sine wave, thereby making the stator's back electromotive force closer to a sine wave, reducing high-order harmonics, and thereby reducing the noise of the EPS motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 The utility model is a rotor core body arranged in a stepped manner;

[0015] Figure 2 It is a cross-sectional view of the rotor core of the utility model.

[0016] In the figure: 1, rotor core; 11, slot hole; 12, magnetic steel sheet; 13, protrusion; 14, weight reduction hole. DETAILED DESCRIPTION

[0017] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only the parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0018] In the description of the present invention, unless otherwise clearly specified and limited, the terms "connected", "connected", and "fixed" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0019] In the present utility model, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0020] In the description of this embodiment, the terms "upper", "lower", "right", etc., are based on the directions or positions shown in the drawings, and are only for the convenience of description and simplified operation, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation of the present invention. In addition, the terms "first" and "second" are only used to distinguish in the description and have no special meaning.

[0021] Under the existing technology, the outer wall of the rotor core is relatively smooth, resulting in the air gap between the rotor and the stator to be a regular ring. The ideal rotor magnetic flux density changes into a sinusoidal wave, but due to the ring shape of the air gap, the magnetic flux density changes in the peak and trough areas are close to a constant, which affects the stator back electromotive force and also makes it close to a constant in the peak and trough areas, resulting in larger values ​​of high-order harmonics during operation, which ultimately leads to the problem of higher noise in the EPS motor.

[0022] In order to solve the above problems, Figure 1 to Figure 2 As shown, the utility model provides a rotor, which includes a rotor core 1, the rotor core 1 is cylindrical, a slot 11 is opened in the rotor core 1, a magnetic steel sheet 12 is inserted in the slot 11, the rotor cores 1 are connected in sequence, a protrusion 13 is formed on the outer wall of the rotor core 1, and the outer surface of the protrusion 13 is arc-shaped; the rotor core 1 is butt-jointed along the axial direction, and the protrusions 13 are staggered with each other.

[0023] Since the rotor core 1 is provided with a protrusion 13, the protrusion 13 will be driven to rotate when the rotor rotates, so that the distance of the air gap can be changed periodically with the rotation of the rotor. The change of the above structure will act on the magnetic flux of the rotor, so that the magnetic flux of the rotor can be changed periodically, so that the fluctuation of the magnetic flux of the rotor can be made to fit the sine wave, especially at the positions of the peaks and troughs that were originally close to a constant, the fluctuation of the magnetic flux can be made closer to the form of a parabola and closer to the style of a sine wave. Since the rotor is closer to a sine wave, the fluctuation of the back electromotive force of the stator will also be close to the form of a sine wave. Since the above conditions are achieved, the high-order harmonics in the EPS motor will be reduced, so that the noise generated by the EPS motor can be reduced.

[0024] The slot hole 11 is circumferentially opened near the edge of the rotor core 1 . The slot hole 11 is in a straight line shape. The length direction of the slot hole 11 is perpendicular to the radial direction of the rotor core 1 . The magnetic steel sheet 12 is embedded in the slot hole 11 .

[0025] The slot 11 of the utility model is in a straight line shape and is located at the edge of the rotor core 1. Its main purpose is to correspond one-to-one with the protrusions 13, so that each protrusion 13 can affect the magnetic density generated by the magnetic steel sheet 12 in the slot 11, thereby making the magnetic density change of the rotor closer to a sine wave, and ultimately reducing high-order harmonics, thereby reducing the noise generated by the EPS motor.

[0026] The radius of the protrusion 13 is r1, the radius of the rotor core 1 is r2, the distance between the protrusion 13 and the center of the circle is r3, r3+r1>r2, a point on the radius direction of the rotor core 1 is selected as the center of the circle, and an arc is drawn according to the above dimensions so that the drawn arc intersects with the outer diameter of the rotor core 1 at two points.

[0027] For different rotor core 1 radii r2, the Maxwell module in ANSYS software is used as a tool to optimize the rotor topology. A point at the best position on the core can be selected as the center of the circle, so that the magnetic flux density change formed by the rotor is close to a sine wave, thereby reducing the noise generated by the EPS motor during operation.

[0028] The protrusions 13 are distributed at equal intervals in the circumferential direction of the rotor core 1 , and the protrusions 13 correspond to the slots 11 one by one.

[0029] A plurality of groups of protrusions 13 are evenly distributed in the circumferential direction of the rotor core 1, and the protrusions 13 are independent of each other, so that the cross-section of the rotor core 1 can be approximately petal-shaped. Through the above steps, the magnetic flux density fluctuation of the rotor can be closer to the form of a sine wave, thereby reducing the noise generated by the EPS motor during operation.

[0030] The rotor cores 1 of the utility model need to be connected in sequence and placed in a cavity inside the stator, wherein the protrusions 13 on the rotor core 1 are distributed in a stepped manner when viewed from a direction perpendicular to the axial direction of the rotor, that is, each rotor core 1 is rotated a certain angle at the position of the previous rotor core 1, and are arranged in sequence according to the above rotation angles, so that the above protrusions 13 can be distributed in a stepped manner. Through the new arrangement, the magnetic flux density of the rotor is closer to a sine wave, which can further reduce the noise generated by the EPS motor during operation.

[0031] In addition, the rotor core 1 of the utility model can also have another arrangement method. When observed perpendicularly to the rotor axis, the protrusions 13 on the multiple groups of rotor cores 1 are distributed in a W shape. Through the above distribution, the magnetic flux density of the rotor can be closer to a sine wave, which can further reduce the noise generated by the EPS motor during operation.

[0032] In the rotor core 1 , a weight-reducing hole 14 is opened along the axial direction of the rotor core 1 , and the weight of the rotor itself can be reduced through the weight-reducing hole 14 .

[0033] The EPS motor also includes a stator, a cavity is formed in the stator, and the rotor is inserted in the cavity of the stator.

[0034] Obviously, the above embodiments of the present invention are merely examples for the purpose of clearly illustrating the present invention, and are not intended to limit the implementation methods of the present invention. For those skilled in the art, various obvious changes, readjustments and substitutions can be made without departing from the scope of protection of the present invention. It is not necessary and impossible to list all implementation methods here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention shall be included in the scope of protection of the claims of the present invention.

Claims

1. A rotor, characterized in that: The invention comprises a rotor core (1), wherein the rotor core (1) is cylindrical, a slot (11) is provided in the rotor core (1), a magnetic steel sheet (12) is inserted into the slot (11), the rotor cores (1) are connected in sequence, a protrusion (13) is formed on the outer wall of the rotor core (1), and the outer surface of the protrusion (13) is arc-shaped; the rotor cores (1) are butt-jointed along the axial direction, and the protrusions (13) are staggered with each other.

2. The rotor according to claim 1, characterized in that The slot (11) is circumferentially opened near the edge of the rotor core (1), the slot (11) is in a straight line shape, the length direction of the slot (11) is perpendicular to the radial direction of the rotor core (1), and the magnetic steel sheet (12) is embedded in the slot (11).

3. The rotor according to claim 1, characterized in that The radius of the protrusion (13) is r1, the radius of the rotor core (1) is r2, the distance between the protrusion (13) and the center of the circle is r3, and r3+r1>r2.

4. The rotor according to claim 2, characterized in that The protrusions (13) are distributed at equal intervals in the circumferential direction of the rotor core (1), and the protrusions (13) correspond one-to-one to the slots (11).

5. The rotor according to claim 1, characterized in that Perpendicular to the rotor axis, the protrusions (13) on the rotor core (1) are distributed in a stepped manner.

6. The rotor according to claim 1, characterized in that Perpendicular to the rotor axis, the protrusions (13) on the rotor core (1) are distributed in a W-shape.

7. The rotor according to claim 1, characterized in that A weight-reducing hole (14) is provided in the rotor core (1) along the axial direction of the rotor core (1).

8. An EPS motor, characterized in that: It comprises the rotor according to any one of claims 1 to 7, and also comprises a stator, wherein the rotor is inserted into the stator.

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