Permanent magnet, permanent magnet motor and clothes airing equipment

Abstract

The utility model discloses a permanent magnet, a permanent magnet motor and clothes airing equipment, and belongs to the technical field of power devices. The arc centers of the inner arc surface and the outer arc surface of the permanent magnet are arranged at intervals, when the permanent magnet is applied to the permanent magnet motor, an air gap is formed between the permanent magnet and a rotor, the air gaps on the two sides are larger than the air gap in the middle, the air gap close to the end of the permanent magnet is increased, concentration and mutation of a magnetic field in the edge area of the air gap can be reduced, and the magnetic field distribution is smoother; alternating radial force causing electromagnetic vibration and noise is weakened, and therefore the electromagnetic vibration and noise are reduced. The permanent magnet motor adopts the permanent magnet, and an air gap can be optimized, so that electromagnetic vibration and noise are reduced. The clothes airing equipment adopts the permanent magnet motor, the performance of the motor can be optimized, the running noise of the motor can be reduced, the noise is lower when the clothes airing equipment is used in a family environment, and the user experience is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of power devices, in particular to a permanent magnet, a permanent magnet motor and a clothes drying device. Background Art

[0002] Permanent magnet DC motors will generate a certain degree of electromagnetic vibration and noise during operation. In many electric devices, electric motors are configured as power sources. For example, in clothes drying equipment, the motor drives the winding wheel to rotate, and the winding wheel reels and unwinds the hanging rope, thereby driving the clothes drying rod to rise and fall. When these devices using electric motors are used in home environments or other environments that require low noise, the noise of the motor operation has a greater impact on the user experience. Therefore, how to reduce the electromagnetic vibration and noise of permanent magnet DC motors during operation has become an urgent problem to be solved. Utility Model Content

[0003] The purpose of the embodiments of the utility model is to provide a permanent magnet, a permanent magnet motor and a clothes drying device, which can reduce the electromagnetic vibration and noise in the permanent magnet motor by optimizing the structure shape of the permanent magnet.

[0004] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0005] A permanent magnet is applied to a motor stator, the permanent magnet having an outer wall and an inner wall; the outer wall comprises an outer arc surface, and the inner wall comprises an inner arc surface;

[0006] The arc center of the outer arc surface is the first arc center, the arc center of the inner arc surface is the second arc center, the second arc center is spaced from the first arc center, and the second arc center is located on a side of the first arc center away from the inner wall.

[0007] Optionally, the inner wall further includes end surfaces respectively connected to both sides of the inner arc surface;

[0008] The inner arc surface is located on the inner circle track; from the side where the end surface is close to the inner arc surface to the side where the end surface is far away from the inner arc surface, the distance between the end surface and the inner circle track increases.

[0009] Optionally, the end surface is a plane, and the plane is tangent to or intersects with the inner arc surface;

[0010] Alternatively, the end surface is a curved surface, and the end surface and the inner curved surface are configured so that arc centers deviate from each other.

[0011] Optionally, the end surface is a plane, and the angle between the end surfaces on both sides is α, 74 degrees ≤ α ≤ 100 degrees;

[0012] The side edges on both sides of the inner arc surface are the second side edges, and the side edge of the end surface away from the inner arc surface is the third side edge; the line connecting the second side edge to the first arc center is the first line, and the line connecting the third side edge to the first arc center is the second line; the angle between the two second lines is β1, and the angle between the two second lines is β2, 60%≤β1 / β2≤90%.

[0013] Optionally, the sides of the outer curved surface are first sides, the outer curved surface has an outer center line located between the two first sides, and the angles between the two first sides and the outer center line are equal; the sides of the inner curved surface are second sides, the inner curved surface has an inner center line located between the two second sides, and the angles between the two second sides and the inner center line are equal;

[0014] The permanent magnet has a middle thickness, the middle thickness is T1, and the middle thickness is the distance between the inner center line and the outer center line; the permanent magnet has a first end thickness, the first end thickness is T2, and the first end thickness is the vertical distance from the first side to the inner wall;

[0015] T1 is greater than T2, 1.05≤T1 / T2≤1.35.

[0016] Optionally, the radial distance from the outer arc surface to the first arc center is a first radius R1, the radial distance from the inner arc surface to the second arc center is a second radius R2, and the distance between the first arc center and the second arc center is an eccentricity r;

[0017] 1≤R1 / R2≤1.7;

[0018] and / or, 11.6≤R1 / r≤21.5;

[0019] And / or, 9.1≤R2 / r≤16.9.

[0020] A permanent magnet motor, comprising:

[0021] A housing having a mounting cavity therein;

[0022] A stator, comprising a plurality of permanent magnets as described in the above scheme; the plurality of permanent magnets are arranged in the installation cavity, and the plurality of permanent magnets are arranged around the first arc center;

[0023] The rotor is arranged in the installation cavity; the rotor is located between the plurality of permanent magnets.

[0024] Optionally, the central axis of the rotor is collinear with the axis where the first arc center is located;

[0025] The gap between the inner wall and the outer surface of the rotor is an air gap, the air gap is σ, and the ratio of the maximum value of σ to the minimum value of σ is greater than 0 and less than or equal to 3.

[0026] Optionally, the inner surface of the housing is the cavity wall of the installation cavity, the cavity wall is provided with a limiting protrusion, and the permanent magnet abuts against the limiting protrusion.

[0027] A clothes drying device comprises the permanent magnet motor as described in the above scheme, and also comprises a clothes drying rod, wherein the motor is used to drive the clothes drying rod to rise and fall.

[0028] The beneficial effect of the utility model is that when the permanent magnet is applied to the permanent magnet motor, an air gap is formed between the inner wall of the permanent magnet and the rotor. In this scheme, the arc centers of the inner arc surface and the outer arc surface of the permanent magnet are spaced apart, so that the air gap increases in the area close to the edge of the permanent magnet, which can reduce the concentration and mutation of the magnetic field in the edge area of ​​the air gap, making the magnetic field distribution smoother, so as to weaken the alternating radial force causing electromagnetic vibration and noise, thereby reducing electromagnetic vibration and noise.

[0029] The permanent magnet motor adopts the permanent magnet to optimize the air gap, thereby reducing electromagnetic vibration and noise. The clothes drying device adopts the permanent magnet motor to optimize the motor performance and reduce the motor running noise. When used in a home environment, the noise is lower, which improves the user experience. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The utility model is further described in detail below based on the drawings and embodiments.

[0031] Figure 1 This is one of the cross-sectional schematic diagrams of the structure of the permanent magnet described in the embodiment of the utility model;

[0032] Figure 2 This is a second cross-sectional schematic diagram of the structure of the permanent magnet according to an embodiment of the utility model;

[0033] Figure 3 for Figure 2 A magnified view of part A in FIG.

[0034] Figure 4 This is a schematic diagram of the partial structure of a permanent magnet according to another embodiment of the utility model;

[0035] Figure 5 This is a schematic diagram of the partial structure of a permanent magnet according to another embodiment of the utility model;

[0036] Figure 6 This is the third cross-sectional schematic diagram of the permanent magnet according to the embodiment of the utility model;

[0037] Figure 7 This is a schematic diagram of the inner side of the permanent magnet according to the embodiment of the utility model;

[0038] Figure 8 This is the fourth cross-sectional schematic diagram of the permanent magnet according to the embodiment of the utility model;

[0039] Fig. 9 This is the fifth cross-sectional schematic diagram of the permanent magnet according to the embodiment of the utility model;

[0040] Fig.10 It is a cross-sectional schematic diagram of the permanent magnet motor according to an embodiment of the utility model;

[0041] Fig.11 It is a schematic diagram of the permanent magnet of the permanent magnet motor according to the embodiment of the utility model being assembled in the casing;

[0042] Fig.12 It is a schematic structural diagram of the casing of the permanent magnet motor described in an embodiment of the utility model.

[0043] In the figure: 10, permanent magnet; 101, first arc center; 102, second arc center; 103, first side; 104, second side; 105, outer center line; 106, inner center line; 107, third side;

[0044] 11. Outer wall; 111. Outer arc surface; 12. Inner wall; 121. Inner arc surface; 122. End surface; 81. First plane; 82. Second plane; 83. First connecting line; 84. Second connecting line; 91. Outer circle trajectory; 92. Inner circle trajectory; 93. Reference circle; 100. Casing; 200. Rotor; 300. Limiting protrusion. DETAILED DESCRIPTION

[0045] In order to make the technical problems solved by the utility model, the technical solutions adopted and the technical effects achieved clearer, the technical solutions of the embodiments of the utility model will be further described in detail below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the utility model.

[0046] In the description of the present invention, unless otherwise clearly specified and limited, the terms "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.

[0047] 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.

[0048] A permanent magnet motor includes a housing, a stator and a rotor. The stator is fixed to the housing and includes main magnetic poles, brushes and a commutator. For a permanent magnet DC motor, the main magnetic poles of the stator are permanent magnets, which are used to generate a magnetic potential source. The rotor is located in the middle of the main magnetic poles. The rotor generally includes an armature core and a winding wrapped around the armature core. The air gap in a permanent magnet motor refers to the gap between the permanent magnet and the rotor. The size and shape of the air gap directly affect the motor's magnetic field distribution, magnetic flux density, electromagnetic force and other performance.

[0049] In the related art, the air gap of the permanent magnet motor is evenly distributed, but there are still many problems such as electromagnetic vibration and noise.

[0050] Based on this, reference Figures 1 to 12 The present application provides a permanent magnet 10 and a permanent magnet motor including the same, which can optimize the air gap and make the air gap present a characteristic of being more uniform in the middle and larger on both sides, which can weaken the armature reaction, reduce the commutation spark during the operation of the motor, and weaken the electromagnetic vibration and noise.

[0051] The permanent magnet motor is suitable for use in household electric appliances that have requirements on operating noise. For example, the permanent magnet motor is suitable for use in electric clothes drying equipment.

[0052] The permanent magnet 10 and a permanent magnet motor including the same will be described below.

[0053] Reference Figure 1 , Figure 2 The cross section of the permanent magnet 10 is tile-shaped, and the two sides of the permanent magnet 10 are respectively an outer wall 11 and an inner wall 12. The outer wall 11 includes at least an outer arc surface 111, and the inner wall 12 includes at least an inner arc surface 121.

[0054] The arc center of the outer arc surface 111 is the first arc center 101, and the outer arc surface 111 is on the outer circular trajectory 91. The arc center of the inner arc surface 121 is the second arc center 102, and the inner arc surface 121 is on the inner circular trajectory 92. The outer circular trajectory 91 is a circular trajectory with the first arc center 101 as the center and the radius being the first radius R1; the arc center of the inner arc surface 121 is a circular trajectory with the second arc center 102 as the center and the radius being the second radius R2.

[0055] In the present application, the second arc center 102 does not coincide with the first arc center 101, there is a gap r between the second arc center 102 and the first arc center 101, and the second arc center 102 is located on the side of the first arc center 101 away from the inner wall 12. Wherein, the first arc center 101 and the second arc center 102 are both located in the first plane 81, and the plane perpendicular to the first plane 81 and passing through the first arc center 101 is the second plane 82. At this time, the second arc center 102 is located on the side of the second plane 82 away from the inner wall 12.

[0056] By eccentrically setting the arc centers of the inner arc surface 121 and the outer arc surface 111 of the permanent magnet 10, the thickness of the middle part of the permanent magnet 10 can be greater than the thickness of the two ends of the permanent magnet 10. The thickness of the permanent magnet 10 refers to the distance between the outer wall 11 and the inner wall 12 in the cross section of the permanent magnet 10. Figure 6 The thickness values ​​of the permanent magnet 10 at multiple positions are shown. From the middle of the permanent magnet 10 to the end of the permanent magnet 10, the thickness of the permanent magnet 10 gradually decreases. Figure 6 The values ​​of T1, T3, T4, and T2 decrease gradually.

[0057] refer to Figure 6 , Fig.10 When the permanent magnet 10 is applied to a permanent magnet motor, the air gap between the inner wall 12 of the permanent magnet 10 and the outer wall 11 of the rotor 200 gradually increases in the area close to the edge of the permanent magnet 10, thereby optimizing the air gap. Figure 6 The reference circle 93 is used to illustrate the outer wall 11 of the rotor 200 to reflect the improvement effect of the shape design of the permanent magnet 10 of the present application on the edge area of ​​the air gap; wherein the reference circle 93 is a circular trajectory with the first arc center 101 as the center and a certain distance from the inner wall 12.

[0058] The permanent magnet 10 in the present application is configured to be eccentrically arranged with the inner arc surface 121 and the outer arc surface 111. When the permanent magnet 10 is applied to a permanent magnet motor, the motor can obtain an uneven air gap, the air gap is relatively uniform in the middle area, and the air gap increases in the area close to the edge of the permanent magnet 10, which can optimize the magnetic field distribution, reduce the concentration and mutation of the magnetic field in the edge area of ​​the air gap, reduce the armature reaction and electromagnetic force fluctuations, reduce the commutation sparks when the motor is running, and weaken the alternating radial force that causes electromagnetic vibration and noise, thereby weakening electromagnetic vibration and noise. The permanent magnet motor is more suitable for use in electric equipment with higher requirements for noise control, and the motor is suitable for use in clothes drying equipment.

[0059] In order to facilitate understanding of the shape of the permanent magnet 10 in the present application, the definitions and positions of the first side 103, the outer center line 105, the second side 104, the inner center line 106, the first plane 81, the first arc center 101, and the second arc center 102 are explained below. The sides on the left and right sides of the outer arc surface 111 are the first side 103, and the outer arc surface 111 has an outer center line 105 located between the two first side 103, and the angles between the two first side 103 and the outer center line 105 are equal. The sides on both sides of the inner arc surface 121 are the second side 104, and the inner arc surface 121 has an inner center line 106 located between the two second side 104, and the angles between the two second side 104 and the inner center line 106 are equal. Figure 2 As shown, the first arc center 101, the second arc center 102, the outer center line 105, and the inner center line 106 are all located in the first plane 81. It should be noted that the first side 103, the outer center line 105, the second side 104, the inner center line 106, the first plane 81, the first arc center 101, the second arc center 102, etc. are used as reference systems, which are not necessarily physical points, lines, or surfaces, but can be virtual points, lines, or surfaces.

[0060] Please refer to Figures 1 to 5 In one embodiment, the inner wall 12 further includes end surfaces 122 connected to both sides of the inner arc surface 121. The end surfaces 122 are used to increase the air gap in the left and right areas of the inner wall 12. Figure 2 , Figure 3 The inner arc surface 121 is located on the inner circle trajectory 92, from the end surface 122 close to the inner arc surface 121 to the end surface 122 away from the inner arc surface 121, refer to Figure 3 , the distance between the end surface 122 and the inner circular trajectory 92 increases, and correspondingly, the air gap formed between the end surface 122 and the rotor 200 will increase.

[0061] On the basis of the eccentric configuration of the inner arc surface 121 and the outer arc surface 111 of the permanent magnet 10, end surfaces 122 are also configured on the left and right sides of the inner arc surface 121. In the permanent magnet motor, the air gap corresponding to the middle area of ​​the permanent magnet 10 is relatively uniform and can be kept small, and the air gap corresponding to the two end areas of the permanent magnet 10 can be gradually increased to weaken the alternating radial force of the electromagnetic vibration and noise.

[0062] The end surface 122 of the inner wall 12 can be configured in at least the following three ways.

[0063] Configuration method 1 of the end surface 122 of the inner wall 12: Figure 3 As shown, the end surface 122 is a plane, and the end surface 122 is tangent to the inner arc surface 121 , that is, the end surface 122 is tangent to the inner circular trajectory 92 .

[0064] Configuration method 2 of the end surface 122 of the inner wall 12: Figure 4 As shown, the end surface 122 is a plane, and the end surface 122 intersects with the inner arc surface 121 , that is, the end surface 122 intersects with the inner circular trajectory 92 .

[0065] Configuration method 3 of the end surface 122 of the inner wall 12: Figure 5 As shown, the end surface 122 is an arc surface, and the arc center of the end surface 122 and the arc center of the inner arc surface 121 are eccentrically arranged. In this way, the air gap can still be increased at the end surface 122.

[0066] It is understandable that, referring to Figure 3 , Figure 4 When the end surface 122 is arranged in the above-mentioned configuration mode 1 or configuration mode 2, that is, when the end surface 122 is a plane, when manufacturing the permanent magnet 10, the entire inner wall 11 can be first processed into a whole arc surface, and the left and right sides of the inner arc surface can be directly cut to form a curved surface. Figure 3 , Figure 4 The approximately triangular structure in the middle S1 area is removed, so that the end surface 122 on one side, the middle inner arc surface 12, and the end surface 122 on the other side can be directly formed on the inner wall 12, so that the end surfaces 122 are provided on both sides of the inner wall, and the air gap is increased in the left and right edge areas. The processing cost is low and it is easy to achieve.

[0067] When the end face 122 is a plane, compared with the manner in which the end face 122 intersects with the inner arc surface 121, in configuration method one, the end face 122 is tangent to the inner arc surface 121, so that the distance between the inner wall 12 and the first arc center 101 gradually increases from the inner arc surface 121 to the end face 122, thereby gradually increasing the air gap between the inner wall 12 of the permanent magnet 10 and the rotor 200, and making the air gap change more uniform, which is conducive to more stable and better alternating radial force, thereby reducing electromagnetic vibration and noise.

[0068] It is understandable that, since the arc center distance between the inner arc surface 121 and the outer arc surface 111 can make the air gap on both sides slightly larger, the requirement for the inclination angle of the flat end surface 122 is reduced, and the air gap requirement on both sides can be met.

[0069] In one embodiment, referring to Figure 8 , the end face 122 is a plane, and the two inclined dotted lines in the figure respectively indicate the virtual planes where the two end faces 122 are located, and the angle between the end faces 122 on both sides is α, 74 degrees ≤ α ≤ 100 degrees. Optionally, 83 degrees ≤ α ≤ 91 degrees, or 86 degrees ≤ α ≤ 88 degrees. When the end face 122 is a plane, by controlling the angle between the two end faces 122, the overall inclination of the end face 122 can be controlled, and the size of the cutting angle at both ends of the inner wall 12 can be controlled, so as to facilitate direct cutting on both sides of the complete inner arc surface 121 to obtain the planes at the two ends, so as to form the shape of the end face 122 with the inner arc surface 121 in the middle and the planes on both sides on the inner wall 12.

[0070] Optionally, when processing the permanent magnet 10, the permanent magnet 10 can be placed on a jig by controlling the angle α, with the center of the jig coinciding with the second arc center 102 of the inner arc surface 121 of the permanent magnet 10, so that the two cutting heads present an angle α, and then the cutting is advanced or lowered simultaneously, while cutting both sides of the inner wall 12, so that the inner wall 12 forms an end face 122 with an inner arc surface 121 in the middle and flat shapes on both sides.

[0071] In one embodiment, referring to Fig. 9 In the case where the inner wall 12 has an inner arc surface 121 in the middle and end surfaces 122 on both sides, the ratio of β1 / β2 is controlled to control the area range of the inner arc surface 121 and the area range of the end surfaces 122 of the inner wall 12, so as to ensure that the air gap in the middle area is relatively uniform and small, so as to reduce the magnetic resistance and reduce the loss of the motor; the air gap is increased in the appropriate edge area to eliminate or improve the vibration and noise problems caused by alternating stress in the edge area of ​​the air gap.

[0072] Please continue to refer to Fig. 9 , the sides of the air gap are the second sides 104, and the side of the end face 122 away from the inner arc surface 121 is the third side 107; the line from the second side 104 to the first arc center 101 is the first line 83, and the line from the third side 107 to the first arc center 101 is the second line 84; the angle between the two second lines 84 is β1, and the angle between the two second lines 84 is β2, 60%≤β1 / β2≤90%, in other words, the curvature of the inner arc surface 121 is 60% to 90% of the curvature of the entire inner wall 12, and the air gap corresponding to the inner arc surface 121 is relatively uniform and small. Optionally, 68%≤β1 / β2≤78%, or 70%≤β1 / β2≤74%.

[0073] In one embodiment, two symmetrical permanent magnets 10 are provided in a motor, and β2 is between 120 degrees and 160 degrees. Optionally, β2 is between 138 degrees and 145 degrees. In other embodiments, a motor may also be provided with a plurality of permanent magnets 10, such as three permanent magnets 10, four permanent magnets 10, five permanent magnets 10, etc., and β2 is in other numerical ranges.

[0074] In one embodiment, referring to Figure 6 , the permanent magnet 10 has a middle thickness T1 and a first end thickness T2. The middle thickness T1 is the distance between the inner center line 106 and the outer center line 105, and the first end thickness T2 is the perpendicular distance from the first side 103 to the inner wall 12. T1 is greater than T2, and the permanent magnet 10 is an unequal thickness structure with a thick middle and thin ends. In this way, when the permanent magnet 10 is applied to a permanent magnet motor, the arc center of the outer arc surface 111 of the permanent magnet 10 coincides with the axis of the motor, and the two ends of the permanent magnet 10 are thinner, so that the air gap formed between the inner wall 12 of the permanent magnet 10 and the rotor 200 can be slightly enlarged at the edges on both sides, thereby obtaining an uneven air gap, weakening the armature reaction, and weakening electromagnetic vibration and noise.

[0075] Optionally, 1.05≤T1 / T2≤1.35, or 1.1≤T1 / T2≤1.3. By controlling the ratio of T1 to T2 within a suitable range, the structural strength and magnetic field uniformity problems caused by excessive thickness difference can be avoided. Controlling the ratio of T1 to T2 within the aforementioned range is conducive to making the magnetic field distribution in the air gap smoother and more stable.

[0076] Reference Figure 2 In one embodiment, the radial distance from the outer arc surface 111 to the first arc center 101 is the first radius R1, the radial distance from the inner arc surface 121 to the second arc center 102 is the second radius R2, and the distance between the first arc center 101 and the second arc center 102 is the eccentricity r.

[0077] Optionally, 1≤R1 / R2≤1.7.

[0078] Optionally, 11.6≤R1 / r≤21.5.

[0079] Optionally, 9.1≤R2 / r≤16.9.

[0080] In one embodiment, 1.2≤R1 / R2≤1.4, 15.5≤R1 / r≤17.5, and 12≤R2 / r≤14.

[0081] In one embodiment, R1 / R2=1.3.

[0082] Among them, for 1≤R1 / R2≤1.7, that is, the radius R1 of the outer arc surface 111 is greater than or equal to the radius R2 of the inner arc surface 121. In the case where the inner arc surface 121 and the outer arc surface 111 are eccentrically set, if the radius R1 of the outer arc surface 111 is smaller than the radius R2 of the inner arc surface 121, it may be necessary to set the eccentricity r to be larger to ensure that the thickness T1 of the middle part of the permanent magnet 10 meets the requirements, and the eccentricity r value is set to be larger, which may lead to a large difference in the degree of curvature between the outer arc surface 111 and the inner arc surface 121, thereby causing the thickness of the permanent magnet 10 to decrease too much from the middle to the end. In this way, the ratio of the middle thickness T1 to the end thickness T2 of the permanent magnet 10 will be too large, and the magnetic field will be uneven, which is not conducive to the performance of the motor. Controlling R1 / R2 to be greater than or equal to 1 is beneficial to ensuring that the curvature of the outer arc surface 111 and the inner arc surface 121 does not differ too much, and also avoids the need to set a large eccentricity, thereby taking into account the requirements for the middle thickness T1 of the permanent magnet 10 and the end thickness T2 of the permanent magnet 10.

[0083] Moreover, by controlling the R1 / R2 value, and at least one of the R1 / r value and the R2 / r value, the curvature of the outer arc surface 111 of the permanent magnet 10, the curvature of the inner arc surface 121, the thickness change of the permanent magnet 10, and the overall shape of the permanent magnet 10 can be controlled to meet the requirements of the motor.

[0084] Please refer to Figures 10 to 12 The permanent magnet motor includes a housing 100, a stator and a rotor 200. The housing 100 has an installation cavity inside. The stator includes a plurality of permanent magnets 10. The plurality of permanent magnets 10 are arranged in the installation cavity. The plurality of permanent magnets 10 are arranged around the axis where the first arc center 101 is located. The permanent magnets 10 are fixed to the inner wall 12 of the housing 100 by welding, clamping, or a stopper. The rotor 200 is arranged in the installation cavity; the rotor 200 is located between the plurality of permanent magnets 10.

[0085] In one embodiment, the permanent magnet motor adopts an eccentric design of the inner arc surface 121 and the outer arc surface 111, and configures the inner wall 12 as the end surfaces 122 on both sides of the middle inner arc surface 121 to optimize the air gap between the inner wall 12 of the permanent magnet 10 and the outer surface of the rotor 200, so that the air gap is relatively uniform in the middle part, and the air gap is slightly increased in the area close to the two ends of the permanent magnet 10, so that the motor obtains an uneven air gap, weakens the armature reaction, reduces the commutation spark when the motor is running, and weakens the electromagnetic vibration and noise.

[0086] In other embodiments, the entire inner wall 12 may be the inner arc surface 121 without the end surface 122 .

[0087] In one embodiment, the central axis of the rotor 200 is colinear with the axis where the first arc center 101 is located, so as to ensure coaxiality and motor efficiency.

[0088] In one embodiment, the gap between the inner wall 12 and the outer surface of the rotor 200 is an air gap, the air gap is σ, and the ratio of the maximum value of σ to the minimum value of σ is greater than 0 and less than or equal to 3. Fig.10 In the equation, the maximum value of σ is σmax, the minimum value of σ is σmin, and 0<σmax / σmin≤3.

[0089] It should be noted that the use of a non-uniform air gap under the main magnetic pole can weaken the alternating radial force, electromagnetic vibration and noise, and by controlling the size of the center air gap and the edge air gap, the ratio of the maximum value of σ to the minimum value of σ is less than 3. When the ratio of the maximum value of σ to the minimum value of σ is 2 or 3, the tooth frequency excitation force can be reduced by about half compared to when a uniform air gap is used (i.e., the air gaps everywhere are σ).

[0090] Optionally, 2≤σmax / σmin≤3.

[0091] Optionally, 2.5≤σmax / σmin≤2.8.

[0092] Optionally, σmin is between 0.4 mm and 0.6 mm, and σmax is between 1.23 mm and 1.43 mm.

[0093] For ease of understanding, the calculation method of the maximum and minimum values ​​of σ is explained below. Fig.10 , the inner wall 12 has an inner center line 106, and the outermost sides of the inner wall 12 are respectively third sides 107, and the two third sides 107 are symmetrical about the inner center line 106. Among them, the line between the inner center line 106 and the first arc center 101 is the third line, and the line length of the third line between the inner wall 12 and the outer surface of the rotor 200 is σmin; correspondingly, the line between the third side 107 and the first arc center 101 is the fourth line, and the line length of the fourth line between the inner wall 12 and the outer surface of the rotor 200 is σmax.

[0094] In one embodiment, if Fig.12 As shown, the inner side of the housing 100 is provided with a plurality of limiting protrusions 300, that is, the cavity wall of the installation cavity is provided with a plurality of limiting protrusions 300, and the outer wall 11 of the permanent magnet 10 abuts against the cavity wall of the installation cavity. The limiting protrusions 300 are used to abut against the upper end or lower end surface of the permanent magnet 10 to achieve the axis positioning of the permanent magnet 10, or the limiting protrusions 300 are used to interfere with the outer wall 11 of the permanent magnet 10 to limit the tendency of the permanent magnet 10 to rotate around the axis of the motor. The limiting protrusions 300 play a role in limiting the position of the permanent magnet 10, thereby reducing vibration and noise.

[0095] The present application also provides a clothes drying device, which includes the permanent magnet motor in the above-mentioned scheme, and the permanent magnet motor also includes a winding wheel, a connecting line and a drying rod. The rotor 200 of the permanent magnet motor is connected to the motor shaft, and the motor shaft is connected to the winding wheel to drive the winding wheel to rotate. The connecting line is wound on the winding wheel, and the other end of the connecting line is connected to the drying rod. When the motor is running, the winding wheel is driven to rotate to reel in or unreel the connecting line, thereby driving the drying rod to rise and fall.

[0096] The vibration and noise problems of the permanent magnet motor in the clothes drying device are improved, which is beneficial to improving the user experience of the clothes drying device when used in households.

[0097] In the description of this article, it should be understood that the terms "upper", "lower", "left", "right" and other directions or positional relationships are based on the directions or positional relationships 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.

[0098] In the description of this specification, the description with reference to the terms "an embodiment", "example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the utility model. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example.

[0099] In addition, it should be understood that although this specification is described according to implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

[0100] The technical principle of the present invention is described above in combination with specific embodiments. These descriptions are only for explaining the principle of the present invention and cannot be interpreted as limiting the protection scope of the present invention in any way. Based on the explanations here, technicians in this field can think of other specific implementation methods of the present invention without creative work, and these methods will fall within the protection scope of the present invention.

Claims

1. A permanent magnet, applied to a motor stator, characterized in that: The permanent magnet (10) comprises an outer wall (11) and an inner wall (12); the outer wall (11) comprises an outer arc surface (111), and the inner wall (12) comprises an inner arc surface (121); The arc center of the outer arc surface (111) is the first arc center (101), the arc center of the inner arc surface (121) is the second arc center (102), the second arc center (102) is spaced from the first arc center (101), and the second arc center (102) is located on a side of the first arc center (101) away from the inner wall (12); The inner wall (12) further comprises end surfaces (122) respectively connected to two sides of the inner arc surface (121); The inner arc surface (121) is located on the inner circular track (92); the distance between the end surface (122) and the inner circular track (92) increases from the side where the end surface (122) is close to the inner arc surface (121) to the side where the end surface (122) is far away from the inner arc surface (121); The end surface (122) is a plane, and the plane is tangent to or intersects with the inner arc surface (121); Alternatively, the end surface (122) is a curved surface, and the end surface (122) and the inner curved surface (121) are configured such that arc centers deviate from each other.

2. The permanent magnet according to claim 1, characterized in that The end surface (122) is a plane, and the angle between the end surfaces (122) on both sides is α, 74 degrees ≤ α ≤ 100 degrees; The side edges on both sides of the inner arc surface (121) are second side edges (104), and the side edge of the end surface (122) away from the inner arc surface (121) is a third side edge (107); a line connecting the second side edge (104) to the first arc center (101) is a first line (83), and a line connecting the third side edge (107) to the first arc center (101) is a second line (84); an angle between the two second lines (84) is β1, and an angle between the two second lines (84) is β2, and 60%≤β1 / β2≤90%.

3. The permanent magnet according to claim 1, characterized in that The side edges on both sides of the outer arc surface (111) are first side edges (103), the outer arc surface (111) has an outer center line (105) located between the first side edges (103) on both sides, and the angles between the two first side edges (103) and the outer center line (105) are equal; the side edges on both sides of the inner arc surface (121) are second side edges (104), the inner arc surface (121) has an inner center line (106) located between the second side edges (104) on both sides, and the angles between the two second side edges (104) and the inner center line (106) are equal; The permanent magnet (10) has a middle thickness, the middle thickness is T1, and the middle thickness is the distance between the inner center line (106) and the outer center line (105); the permanent magnet (10) has a first end thickness, the first end thickness is T2, and the first end thickness is the vertical distance from the first side (103) to the inner wall (12); T1 is greater than T2, 1.05≤T1 / T2≤1.

35.

4. The permanent magnet according to claim 1, characterized in that The radial distance from the outer arc surface (111) to the first arc center (101) is a first radius R1, the radial distance from the inner arc surface (121) to the second arc center (102) is a second radius R2, and the distance between the first arc center (101) and the second arc center (102) is an eccentric distance r; 1≤R1 / R2≤1.7; and / or, 11.6≤R1 / r≤21.5; And / or, 9.1≤R2 / r≤16.

9.

5. A permanent magnet motor, characterized in that: include: A housing (100) having a mounting cavity therein; A stator, comprising a plurality of permanent magnets (10) according to any one of claims 1 to 4; the plurality of permanent magnets (10) are arranged in the mounting cavity, and the plurality of permanent magnets (10) are arranged around the first arc center (101); A rotor (200) is disposed in the installation cavity; the rotor (200) is located between the plurality of permanent magnets (10).

6. The permanent magnet motor according to claim 5, characterized in that: The central axis of the rotor (200) is collinear with the axis where the first arc center (101) is located; The gap between the inner wall (12) and the outer surface of the rotor (200) is an air gap, the air gap is σ, and the ratio of the maximum value of σ to the minimum value of σ is greater than 0 and less than or equal to 3.

7. The permanent magnet motor according to claim 5, characterized in that: The inner surface of the housing (100) is the cavity wall of the installation cavity, the cavity wall is provided with a limiting protrusion (300), and the permanent magnet (10) abuts against the limiting protrusion (300).

8. A clothes drying device, characterized in that: It comprises the permanent magnet motor as claimed in any one of claims 5 to 7, and also comprises a drying rod, wherein the motor is used to drive the drying rod to rise and fall.

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