Rotor, motor and industrial robot

Abstract

The utility model discloses a rotor, a motor and an industrial robot, the rotor comprises a rotor punching sheet and a permanent magnet, the rotor punching sheet is provided with a plurality of boss parts located in the radial direction of the rotor punching sheet, the outer periphery of the rotor punching sheet and two adjacent boss parts form a limiting groove, the permanent magnet is arranged in the limiting groove, and the permanent magnet is arranged in the limiting groove. The two boss parts can limit the movement of the permanent magnet in the circumferential direction, the boss parts are provided with grooves, the size of the boss parts can be reduced and the magnetic leakage phenomenon can be improved by arranging the grooves in the boss parts, the rotor punching sheet rotates around the central axis, and the permanent magnet comprises an outer side face located on the radial outer side. The distance from the middle portion of the outer side face in the circumferential direction to the central axis is larger than the distance from the side portion of the outer side face in the circumferential direction to the central axis, namely, the outer side face of the permanent magnet is eccentrically designed, and the harmonic content in the magnetic flux density waveform of an air-gap magnetic field can be reduced. The working condition requirements of high rotating speed and low torque pulsation can be met at the same time.

Description

Technical Field

[0001] The utility model relates to the technical field of motors, in particular to a rotor, a motor and an industrial robot. Background Art

[0002] In the technical field of industrial robots, some types of industrial robots require the motor to have a higher speed and lower torque pulsation in the working environment, which brings difficulties to the design, installation and fixation of the surface-mounted permanent magnet synchronous motor. In the related art, in order to limit the permanent magnet, a fixed boss for limiting the permanent magnet is arranged on the periphery of the rotor punching to ensure that the permanent magnet is not easy to fly out of the rotor and cause structural separation during the high-speed operation of the motor. However, since the fixed boss is located between two adjacent permanent magnets, and the polarity of the two permanent magnets close to each other is different, since the magnetic resistance of the fixed boss is small, according to the principle that the magnetic flux lines pass through the minimum magnetic resistance, part of the magnetic flux lines of the two permanent magnets will be directly closed through the fixed boss, causing leakage magnetic flux, thereby reducing the output torque of the motor and reducing the anti-demagnetization ability. And it causes a large change in the magnetic permeability of the permanent magnet, resulting in an increase in the cogging torque of the motor, which in turn leads to a large torque pulsation of the motor. Utility Model Content

[0003] The utility model aims to solve at least one of the technical problems existing in the prior art. To this end, the utility model proposes a rotor, which can improve the magnetic leakage phenomenon by arranging a groove on the boss part to reduce the volume of the boss part, and the eccentric design of the outer side of the permanent magnet can reduce the harmonic content in the magnetic flux density waveform of the air gap magnetic field, so that the waveform of the magnetic flux density is more consistent with the sine wave, reduce the cogging torque and torque pulsation, and can simultaneously meet the working conditions of high speed and low torque pulsation.

[0004] The utility model also provides a motor with the rotor.

[0005] The utility model also provides an industrial robot with the motor.

[0006] According to the rotor of the first aspect of the utility model, the embodiment includes: a rotor punching, which is provided with a plurality of bosses located in the radial direction of the rotor punching, and the outer peripheral edge of the rotor punching and two adjacent bosses are configured to form a limiting groove; a permanent magnet, which is arranged in the limiting groove and the circumferential movement of the permanent magnet is limited by the two bosses; wherein the boss is provided with a groove, and the groove is located on the radial outer side of the boss and in the circumferential middle of the boss; the rotor punching rotates around the central axis, and the permanent magnet includes an outer side surface located on the radial outer side, and the distance from the circumferential middle of the outer side surface to the central axis is greater than the distance from the circumferential side of the outer side surface to the central axis.

[0007] According to the rotor of the first embodiment of the utility model, there are at least the following beneficial effects: by arranging a plurality of bosses on the periphery of the rotor punching sheet, a limiting groove is formed between two adjacent bosses, and the limiting groove can limit the permanent magnet. When the rotor rotates at high speed, the permanent magnet is not easy to separate from the rotor, meeting the high speed working condition requirements. By arranging the groove on the boss, the volume of the boss is reduced. Since the groove is an air gap, the magnetic resistance of the air gap is large, and the magnetic flux of the permanent magnet is not easy to pass through the air gap at the groove. It can also be understood that the magnetic flux passing through the boss is reduced, thereby improving the leakage phenomenon, reducing the change of the permanent magnet magnetic permeability, reducing the tooth torque, thereby suppressing the torque pulsation, allowing the motor to run more smoothly, meeting the working condition requirements of low torque pulsation, and improving the anti-demagnetization ability. And by making the distance from the middle of the circumference of the outer surface to the central axis greater than the distance from the side of the circumference of the outer surface to the central axis, it can be understood that the outer surface of the permanent magnet is designed eccentrically. Since the distance from the stator to the central axis is basically unchanged, the air gap between the permanent magnet and the stator is gradual, which can change the distribution of the air gap magnetic field, reduce the harmonic content in the magnetic flux density waveform of the air gap magnetic field, make the magnetic flux density waveform more consistent with the sine wave, reduce the cogging torque, thereby suppressing the torque pulsation, and make the motor run more smoothly, meeting the working requirements of low torque pulsation.

[0008] According to some embodiments of the utility model, the outer surface includes a first line segment, a second line segment, and a third line segment arranged in sequence along the circumferential direction, the distance from the second line segment to the central axis is greater than the distance from the first line segment and the third line segment to the central axis, the second line segment is an arc, the circle where the arc is located is a virtual circle, and the first line segment and the third line segment are located within the virtual circle.

[0009] According to some embodiments of the present invention, the first line segment and the third line segment are symmetrically arranged about a circumferential symmetry line, and the first line segment and the third line segment are both arcs and are eccentrically arranged with respect to the second line segment.

[0010] According to some embodiments of the present invention, the projection length of the line connecting the center of the first line segment and the center of the second line segment on the circumferential symmetry line is h3, satisfying 25cm≤h3≤30cm.

[0011] According to some embodiments of the present invention, the angle between the line connecting the center of the first line segment and the center of the second line segment and the circumferential symmetry line is α, which satisfies 5°≤α≤7°.

[0012] According to some embodiments of the present invention, the maximum length from the fitting surface of the boss portion and the permanent magnet to the radially outer side of the boss portion, and the projection length on the circumferential symmetry line of the permanent magnet is h1, which satisfies 1mm≤h1≤1.2mm.

[0013] According to some embodiments of the present invention, the wall thickness of the side wall of the groove is d, satisfying 0.5mm≤d≤0.7mm.

[0014] According to some embodiments of the utility model, the outer periphery of the rotor punching sheet is provided with positioning protrusions, and the permanent magnet abuts against the positioning protrusions, so that a space for accommodating the adhesive is formed between the outer periphery of the rotor punching sheet and the permanent magnet.

[0015] According to some embodiments of the present utility model, the radial height of the positioning protrusion is h2, which satisfies 0.1mm≤h2≤0.3mm.

[0016] The motor according to the second embodiment of the utility model includes the rotor of the first embodiment.

[0017] The motor according to the second aspect of the present invention comprises the rotor of the first aspect, and thus has at least the above-mentioned beneficial effects, which will not be described in detail here.

[0018] An industrial robot according to an embodiment of the third aspect of the utility model comprises the motor of the embodiment of the second aspect.

[0019] The industrial robot according to the third aspect of the present invention comprises the motor according to the second aspect and thus has at least the above-mentioned beneficial effects, which will not be described in detail herein.

[0020] Additional aspects and advantages of the present invention will be given in part in the following description, and in part will become apparent from the following description, or will be learned through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The present invention is further described below with reference to the accompanying drawings and embodiments, wherein:

[0022] Figure 1 It is a schematic diagram of the structure of the rotor of some embodiments of the utility model;

[0023] Figure 2 for Figure 1 The enlarged view of point A in the middle;

[0024] Figure 3 It is a schematic diagram of the structure of the rotor of some embodiments of the utility model;

[0025] Figure 4 for Figure 3 The enlarged view of point B in the middle;

[0026] Figure 5 It is a schematic diagram of the structure of the rotor punching of the rotor in some embodiments of the utility model;

[0027] Figure 6 for Figure 5 Enlarged view of point C in the middle;

[0028] Figure 7 for Figure 5 The enlarged view of point D in the middle;

[0029] Figure 8 It is a schematic diagram of the structure of the permanent magnet of the rotor in some embodiments of the utility model;

[0030] Fig. 9 It is a schematic diagram of the structure of the permanent magnet of the rotor in some embodiments of the utility model;

[0031] Fig.10 It is a schematic structural diagram of a surface-mounted permanent magnet synchronous motor according to some embodiments of the utility model.

[0032] Reference numerals:

[0033] Surface mounted permanent magnet synchronous motor 1000;

[0034] Rotor 100, rotor punching 110, boss portion 111, groove 1111, first protrusion 1112, second protrusion 1113, first wall surface 1114, second wall surface 1115, limit groove 112, positioning convex point 113, process groove 114, permanent magnet 120, outer side surface 121, first line segment 1211, second line segment 1212, third line segment 1213, middle position 1214, side position 1215, inner side surface 122, left side surface 123, right side surface 124, fitting surface 125, bonding space 130;

[0035] Stator 200;

[0036] Output shaft 300;

[0037] Housing 400. DETAILED DESCRIPTION

[0038] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0039] Reference Figure 1 As shown in FIG. 1 , a rotor 100 provided in an embodiment of the present invention is provided. The rotor 100 includes a rotor punching 110 and a permanent magnet 120. The rotor punching 110 is made of a metal material and has a substantially annular structure. Figure 1The arrow directions in the figure can define the radial and circumferential directions of the rotor sheet 110. The radial direction can be understood as the radial direction of the rotor sheet 110, and the circumferential direction can be understood as the circumferential direction of the outer periphery of the rotor sheet 110. The direction radially toward the center of the rotor sheet 110 is called the radial inner side, and the direction radially away from the center of the rotor sheet 110 is called the radial outer side. Figure 5 As shown, at the outer periphery of the rotor punching 110, the rotor punching 110 is provided with a plurality of bosses 111 located in the radial direction of the rotor punching 110. It can also be understood that the plurality of bosses 111 protrude toward the outside, and the plurality of bosses 111 are arranged at intervals along the circumference of the rotor punching 110. It should be explained that, referring to Figure 3 and Figure 4 , the boss portion 111 can protrude outward along the radial direction of the rotor punching 110, that is, the protruding direction of the boss portion 111 is the same as the radial direction of the rotor punching 110, which can make the side wall of the boss portion 111 relatively straight, so that the boss portion 111 and the permanent magnet 120 can be easily abutted. Alternatively, the protruding direction of the boss portion 111 can also deviate from the radial direction of the rotor punching 110, and the protruding direction is inclined relative to the radial direction, that is, the protruding direction of the boss portion 111 has a certain angle with the radial direction. Since the boss portion 111 protrudes outward, refer to Figure 6 As shown, a groove structure is naturally formed between two adjacent bosses 111, and the groove structure can be understood as a limiting groove 112. It can also be understood that the limiting groove 112 is configured between the outer periphery of the rotor punching 110 and the two adjacent bosses 111, that is, the boss 111 is configured as the side wall of the limiting groove 112, and the outer periphery of the rotor punching 110 is configured as the bottom wall of the limiting groove 112. The permanent magnet 120 is arranged in the limiting groove 112, and the limiting groove 112 is used to install the permanent magnet 120. The length of the limiting groove 112 along the circumferential direction matches the length of the permanent magnet 120 along the circumferential direction. The permanent magnet 120 is located between two adjacent bosses 111. The two bosses 111 can respectively abut on both sides of the permanent magnet 120. When the rotor 100 rotates at high speed, the two bosses 111 can limit the movement of the permanent magnet 120 along the circumferential direction, play a limiting role, and avoid the permanent magnet 120 from moving. The fixing effect is good and meets the working conditions of high speed. In some embodiments, the boss 111 is an axisymmetric structure with a relatively standardized shape, which can be easily manufactured.

[0040] It should be noted that after the boss portion 111 is arranged, the boss portion 111 separates the two permanent magnets 120. The distance between the two adjacent permanent magnets 120 is large, which will cause an air gap to appear between the two adjacent permanent magnets 120. In addition, the polarity of the side of the two adjacent permanent magnets 120 that are close to each other is different, and part of the magnetic flux lines of the two permanent magnets 120 will be closed to each other. Compared with the boss portion 111 made of metal material, the magnetic resistance of the air gap is greater. According to the principle that the magnetic flux lines pass through the smallest magnetic resistance, part of the magnetic flux lines of the permanent magnet 120 will be closed through the boss portion 111. Based on this, refer to Figure 6 As shown, in this embodiment, the boss portion 111 is provided with a groove 1111, and the groove 1111 is located radially outside the boss portion 111, and the groove 1111 is located in the circumferential middle of the boss portion 111. It can be understood that the groove 1111 is located in the center. The groove 1111 can be understood as being formed by removing a portion of the material of the boss portion 111, which reduces the volume of the boss portion 111. Since the groove 1111 is an air gap, the magnetic resistance of the air gap is greater than that of the solid structure of the boss portion 111, and the magnetic flux lines of the permanent magnet 120 are not easy to pass through the air gap at the groove 1111. It can also be understood that the magnetic flux lines passing through the boss portion 111 are reduced, which can reduce magnetic leakage. It can also be understood that more magnetic flux lines of the permanent magnet 120 will pass through the stator, optimizing the distribution of the magnetic field, making the magnetic field at the boss portion 111 easier to saturate, and the magnetic permeance of the permanent magnet 120 is not easy to change significantly, which can reduce the cogging torque, thereby suppressing the torque pulsation, making the motor run more smoothly, meeting the working condition requirements of low torque pulsation, and improving the anti-demagnetization ability. The rotor 100 can be used in working occasions with high speed and low torque pulsation working conditions, such as in the joint drive, end effector drive or mobile industrial robot drive of industrial robots. It is understandable that the shape of the groove 1111 can be semicircular, trapezoidal, square or other shapes as long as the volume of the boss portion 111 can be reduced.

[0041] It should be noted that after using ansoft software to simulate the motor without groove 1111 on the boss part 111 and the motor with groove 1111 on the boss part 111, the results showed that for the motor without groove 1111 on the boss part 111, the minimum magnetic flux density is 0.3530T, and for the motor with groove 1111 on the boss part 111, the minimum magnetic flux density is 0.4329T. Obviously, the value of the minimum magnetic flux density is improved, which proves that the anti-demagnetization ability of the motor is improved.

[0042] Reference Figure 2 and Figure 6As shown, after the groove 1111 is provided on the boss portion 111, a structure of a first protrusion 1112 and a second protrusion 1113 will be left on both sides of the boss portion 111. Taking the first protrusion 1112 as an example, the first protrusion 1112 has two wall surfaces arranged opposite to each other, one of which is a first wall surface 1114, and the other is a second wall surface 1115. The first wall surface 1114 is located on a side of the first protrusion 1112 close to the permanent magnet 120, and the first wall surface 1114 is used to abut against the permanent magnet 120. The second wall surface 1115 is located on a side of the first protrusion 1112 close to the groove 1111, and the second wall surface 1115 can also be understood as a part of the side wall of the groove 1111. Since the first wall surface 1114 is used to abut against the permanent magnet 120, the protruding direction of the boss portion 111 can be understood as the extension direction of the first wall surface 1114. When the first wall surface 1114 and the second wall surface 1115 are parallel to each other, the protruding direction of the boss portion 111 can be understood as the extension direction of the first wall surface 1114 and the second wall surface 1115. When the boss portion 111 is an axisymmetric structure, the first protrusion 1112 and the second protrusion 1113 are of the same structure. It should be noted that part of the magnetic field of the permanent magnet 120 will pass through the first protrusion 1112 and the second protrusion 1113. The volume size of the first protrusion 1112 and the second protrusion 1113 will affect the leakage magnetic phenomenon and also affect the limiting effect on the permanent magnet 120.

[0043] It is understandable that, referring to Figure 2 , Figure 6 and Figure 8 As shown, in some embodiments, the permanent magnet 120 is symmetrical about the circumferential symmetry line X2, the boss portion 111 can protrude outward along the circumferential symmetry line X2, the permanent magnet 120 is fitted with at least part of the first wall surface 1114 of the boss portion 111, thereby forming a fitting surface 125, the permanent magnet 120 can be fitted with part of the first wall surface 1114, and the permanent magnet 120 can also be fitted with all of the first wall surface 1114. The fitting surface 125 has a maximum length from the radial outside of the boss portion 111, and the length of the projection of the maximum length on the circumferential symmetry line X2 is h1, and h1 satisfies 1mm≤h1≤1.2mm. h1 can be understood as the protruding length of the boss portion 111 on the circumferential symmetry line X2, and can also be understood as the height of the boss portion 111. The size of h1 is related to the volume of the boss portion 111 and the area of ​​the fitting surface 125. The circumferential symmetry line X2 is the same as the radial direction of the rotor punching sheet 110, and h1 can be understood as the radial length of the boss portion 111, that is, h1 is the radial projection length of the line connecting the radial outermost position and the radial innermost position of the boss portion 111. In this embodiment, h1 satisfies 1mm≤h1≤1.2mm, which can make the volume of the boss portion 111 smaller, reduce magnetic leakage, and ensure that the area of ​​the fitting surface 125 is larger, thereby improving the limiting effect on the permanent magnet 120.

[0044] Specifically, refer to Figure 2 , Figure 4 and Figure 6 As shown, there is a first contact point F1 and a second contact point F2 between the permanent magnet 120 and the first wall surface 1114. F1 and F2 can be understood as the endpoints on the fitting surface 125. F1 is the radially innermost position of the fitting surface 125, and F2 is the radially outermost position of the fitting surface 125. The length of the line connecting F1 and F2 can be understood as the radial length of the fitting surface 125. Taking the first protrusion 1112 as an example, the first protrusion 1112 has a highest point F3 and a lowest point F4. F3 can be understood as the radially outermost position of the first protrusion 1112, and F4 can be understood as the radially innermost position of the first protrusion 1112, that is, F3 is the highest position of the first protrusion 1112, and F4 is the lowest position of the first protrusion 1112. At the same time, F3 is also the highest position of the entire boss portion 111. In some embodiments, F1 and F4 are at the same position, and F1 is also the radially innermost position of the first protrusion 1112. The length of the line connecting F1 to F3 is the maximum length from the fitting surface 125 to the radial outer side of the boss portion 111, and the projected length of the maximum length on the circumferential symmetry line X2 is h1. The angle between the line connecting F1 to F3 and the circumferential symmetry line X2 is σ, and h1 is equal to the product of the line connecting F1 to F3 and cosσ. h1 can be understood as the protruding length of the first protrusion 1112. The circumferential symmetry line X2 is the same as the radial direction of the rotor punching 110. h1 can be understood as the length of the first protrusion 1112 along the radial direction. The size of h1 is related to the volume of the boss portion 111 and the area of ​​the fitting surface 125. The larger h1 is, the larger the area of ​​the fitting surface 125 is, and the better the limiting effect on the permanent magnet 120 is, but it will cause the radial length of the first protrusion 1112 to be larger, the volume of the first protrusion 1112 to be larger, and the magnetic flux lines passing through the first protrusion 1112 to be more, and the magnetic leakage phenomenon is more serious, so it needs to be considered comprehensively. In this embodiment, h1 is designed to meet 1mm≤h1≤1.2mm, which can make the area of ​​the fitting surface 125 larger, while ensuring that the volume of the first protrusion 1112 is small, ensuring the limiting effect on the permanent magnet 120 and taking into account the effect of reducing magnetic leakage.

[0045] In some embodiments, F2 and F3 overlap, which can also be understood as the protruding length of the boss portion 111 is equal to the length of the fitting surface 125, that is, σ is 0 degrees, h1 is equal to the length of the line connecting F1 and F2, and at this time, the permanent magnet 120 fits with the entire first wall surface 1114 to form the fitting surface 125. In some embodiments, refer to Figure 2 As shown, the maximum radial length of the boss portion 111 is smaller than the minimum radial length of the permanent magnet 120 . It can also be understood that the permanent magnet 120 only fits a portion of the first wall surface 1114 of the boss portion 111 , ensuring that the volume of the boss portion 111 is relatively small.

[0046] It is understandable that, referring to Figure 2 and Figure 6 As shown, in some embodiments, the wall thickness of the side wall of the groove 1111 is d, and d can also be understood as the wall thickness of the first protrusion 1112 or the second protrusion 1113, that is, the distance between the first wall surface 1114 and the second wall surface 1115. Taking the first protrusion 1112 as an example, it should be noted that the size of d will affect the structural strength of the first protrusion 1112 and the volume of the groove 1111. If d is too small, although the volume of the groove 1111 can be guaranteed to be larger, the effect of reducing magnetic leakage is more obvious, but the structural strength of the first protrusion 1112 will be poor. Taking into account the structural strength of the first protrusion 1112 and the volume of the groove 1111, the design of this embodiment satisfies 0.5mm≤d≤0.7mm, ensuring that the structural strength of the first protrusion 1112 is relatively large, and at the same time, the volume of the groove 1111 is relatively large, ensuring that the magnetic leakage phenomenon is reduced. It should be noted that when measuring the value of d, the value of d can be measured by clamping the first protrusion 1112 or the second protrusion 1113 with a vernier caliper. It can also be understood that the value of d can be measured by clamping the first wall 1114 and the second wall 1115 with a vernier caliper, or the value of d can be directly measured with a ruler.

[0047] Reference Fig. 9 As shown, in some embodiments, the permanent magnet 120 includes an outer side surface 121, an inner side surface 122, a left side surface 123 and a right side surface 124, the outer side surface 121 is located on the radial outside of the permanent magnet 120, the outer side surface 121 faces the stator, the inner side surface 122 is located on the radial inside of the permanent magnet 120, the left side surface 123 is located on the left side of the permanent magnet 120, and the right side surface 124 is located on the right side of the permanent magnet 120, the left side surface 123, the outer side surface 121, the right side surface 124 and the inner side surface 122 are connected in sequence to form a circle of outer circumferential surface, the left side surface 123 and the right side surface 124 are used to abut against the first wall surface 1114, the left side surface 123 and the right side surface 124 extend radially, the left side surface 123 and the right side surface 124 can be designed as a plane, mainly used to abut against the first wall surface 1114 of the boss portion 111, and the first wall surface 1114 can also be designed as a plane, which can increase the area of ​​the fitting surface 125.

[0048] Reference Figure 2 and Figure 7As shown, in some embodiments, the outer periphery of the rotor punching sheet 110 is provided with a positioning protrusion 113, the positioning protrusion 113 is located in the limiting groove 112, the positioning protrusion 113 protrudes radially outward, and the inner side surface 122 of the permanent magnet 120 abuts against the positioning protrusion 113 to play a positioning role. Due to the presence of the positioning protrusion 113, a bonding space 130 is formed between the inner side surface 122 and the outer periphery of the rotor punching sheet 110. The bonding space 130 can accommodate an adhesive, and the adhesive can The rotor punching 110 and the permanent magnet 120 are bonded together to play a fixing role. The bonding space 130 can be understood as a gap. The inner side surface 122 can be a plane, and the plane is opposite to the bottom wall of the limiting groove 112. The bottom wall of the limiting groove 112 can be designed as a plane parallel to the inner side surface 122, so that the distance between the inner side surface 122 and the bottom wall of the limiting groove 112 is basically unchanged. The bonding space 130 is distributed more evenly, and the adhesive is more uniform, which can improve the bonding and fixing effect.

[0049] It is understandable that, referring to Figure 2 and Figure 7 As shown, in some embodiments, the radial height of the positioning protrusion 113 is h2, which satisfies 0.1mm≤h2≤0.3mm. h2 can also be understood as the distance between the inner side 122 of the permanent magnet 120 and the bottom wall of the limiting groove 112, or h2 can also be understood as the thickness of the adhesive in the bonding space 130. The cross-section of the positioning protrusion 113 can be square, semicircular, trapezoidal or other shapes.

[0050] It is understandable that, referring to Figure 2 and Figure 7 As shown, in some embodiments, a process groove 114 is provided on the outer periphery of the rotor punching 110. For one boss portion 111, the number of process grooves 114 is two, and the two process grooves 114 are respectively located on both sides of the boss portion 111 along the circumferential direction. The process groove 114 can be roughly semicircular, or can be an arc or other shape. When the permanent magnet 120 is fitted with the boss portion 111, the inner side surface 122 of the permanent magnet 120 will face the process groove 114, and the inner side surface 122 does not contact the side wall of the process groove 114, which is conducive to the fitting of the permanent magnet 120 and the boss portion 111. It can also be understood that after the process groove 114 is provided, part of the outer periphery of the rotor punching 110 can be removed, or the angle formed between the side wall of the boss portion 111 and the outer periphery of the rotor punching 110 can be removed, so that the permanent magnet 120 and the boss portion 111 are better fitted. In addition, the process groove 114 can also reduce the volume of the rotor punching 110. The air gap magnetic resistance at the process groove 114 is relatively large, and the magnetic flux lines of the permanent magnet 120 are not easy to pass through the process groove 114, so that the magnetic flux lines of the permanent magnet 120 passing through the rotor punching 110 are reduced, further improving the leakage magnetic phenomenon.

[0051] It should be explained that the air gap magnetic field refers to the magnetic field between the rotor 100 and the stator in the motor, which is generated by the permanent magnet 120 and forms a closed magnetic circuit between the rotor 100 and the stator. The air gap magnetic field is a key factor in the motor to generate torque. The distribution of the air gap magnetic field in space is uneven and is affected by various factors, such as the air gap, the thickness or shape of the permanent magnet 120, etc. The air gap refers to the gap between the permanent magnet 120 and the stator.

[0052] Reference Figure 1 As shown, the rotor sheet 110 has a central axis X1, referring to Figure 1 and Fig.10 As shown in the arrow direction, the central axis X1 extends in the front-rear direction, the rotor punching 110 rotates around the central axis X1, and the entire rotor 100 also rotates around the central axis X1. Figure 8 and Fig. 9 As shown, the circumferential direction of the outer side surface 121 has a middle position 1214 and a side position 1215, and the side position 1215 is located on both sides of the middle position 1214. The line connecting the midpoint of the middle position 1214 and the central axis X1 coincides with the circumferential symmetry line X2. The middle position 1214 is understood to be the position in the middle of the outer side surface 121 or the position close to the circumferential symmetry line X2, and the side position 1215 is understood to be the position close to the two ends of the outer side surface 121 or the position away from the circumferential symmetry line X2. Figure 8 Taking the arrow direction in FIG. 1 as an example, the middle position 1214 can be understood as the position of the outer side surface 121 close to the left and right ends. Figure 8 As shown, the distance from the middle position 1214 of the outer side surface 121 to the central axis X1 is D2, and the distance from the side position 1215 of the outer side surface 121 to the central axis X1 is D1. In some embodiments, the outer side surface 121 of the permanent magnet 120 can be eccentrically designed so that D2 is greater than D1. Specifically, at the middle position 1214, with the circumferential symmetry line X2 as the starting point, D2 gradually decreases toward the left direction or the right direction, or it can be that at the side position 1215, D1 gradually decreases toward the direction away from the middle position 1214. After such a design, the distance from the outer side surface 121 to the central axis X1 at the outer side surface 121 of the permanent magnet 120 can be gradually reduced from the middle position 1214 to the side position 1215. Since the distance from the stator to the central axis X1 is basically unchanged, the air gap gradually increases from the middle position 1214 to the side position 1215.

[0053] Specifically explain the above-mentioned embodiment that "the distance from the outer side surface 121 to the central axis X1 is gradually reduced", refer to Figure 8As shown, a point on the outer side surface 121 is connected to the central axis X1, and the angle between the connecting line and the circumferential symmetry line X2 is β. Counting from the circumferential symmetry line X2 to the left, β is a positive angle, and Y represents the distance from the point to the central axis X1. Assume function f:β→Y, "the distance from the outer side surface 121 to the central axis X1 is gradually decreasing" means that: the function f(β) can be monotonically decreasing, and the function f(β) is not a constant function, that is, for any β2>β1, there is f(β2)≤f(β1), and at the same time, there is β4>β3, so that f(β4)<f(β3) holds. For example, at the middle position 1 At 214, as the angle β increases, the distance from the middle position 1214 to the central axis X1 can remain unchanged, that is, at the middle position 1214, any β2>β1, there is f(β2)=f(β1), and at the side position 1215, as the angle β increases, the distance from the side position 1215 to the central axis X1 begins to decrease again, that is, β3 can be taken at the middle position 1214, and β4 can be taken at the side position 1215, so that f(β4)<f(β3) holds; the function f(β) can also be strictly decreasing, that is, for any β2>β1, there is f(β2)<f(β1). To summarize simply, that is, from the middle position 1214 to the side position 1215, the distance from the outer surface 121 to the central axis X1 can remain unchanged at a certain position, but it needs to maintain a gradually decreasing trend overall. It should be noted that, for the terms "gradually decrease" or "gradually increase" described in the present invention, their meanings can be referred to the explanation content of this paragraph. The "air gap gradually increases from the middle position 1214 to the side position 1215" described in the above embodiment is the same. The air gap can remain unchanged at a certain position, but the overall trend of gradually increasing needs to be maintained, which will not be elaborated here.

[0054] This embodiment can reduce the harmonic content in the magnetic flux density waveform of the air gap magnetic field by changing the distribution law of the air gap, so that the magnetic flux density waveform of the air gap magnetic field tends to a sine wave, and the back electromotive force waveform of the motor can tend to a sine wave, which can reduce the cogging torque and the torque pulsation of the motor, so that the motor load can run more smoothly at high speed, with lower vibration and noise, more precise control accuracy, and more superior and reliable motor performance.

[0055] Specifically, the outer side surface 121 can be a curved surface or a combination of multiple curved surfaces. When viewed from the side, the edge line of the outer side surface 121 can be a circular arc, an elliptical arc, a parabola or other types of curves, or can be composed of multiple circular arcs with different radii, or can be composed of multiple elliptical arcs with different eccentricities, or can be composed of multiple parabolas with different focal lengths, or can be composed of multiple circular arcs, elliptical arcs and parabolas. It can be understood that the permanent magnet 120 is in a bread shape. Alternatively, in some embodiments, the outer side surface 121 is a combination of multiple non-parallel planes, and the multiple planes are eccentrically arranged. The edge line of the outer side surface 121 can be composed of multiple non-parallel straight line segments, and the permanent magnet 120 is in a tile shape. Specifically, taking the edge line of the outer surface 121 as an example of an arc line, the center of the arc line can be offset from the central axis X1. After such an arrangement, the distance from the arc line to the central axis X1 can be gradual along the circumferential direction, either gradually increasing or gradually decreasing. The distance from the middle of the arc line to the central axis X1 is greater than the distance from the side of the arc line to the central axis X1. If you go from the middle of the arc line to both sides, the distance from the arc line to the central axis X1 is gradually decreasing.

[0056] It is understandable that, referring to Fig. 9As shown, in some embodiments, the outer side surface 121 includes a first line segment 1211, a second line segment 1212, and a third line segment 1213 sequentially arranged along the circumferential direction. It can also be understood that the outer side surface 121 is composed of the first line segment 1211, the second line segment 1212, and the third line segment 1213, and the first line segment 1211, the second line segment 1212, and the third line segment 1213 are sequentially connected together, and the second line segment 1212 is located between the first line segment 1211 and the third line segment 1213. 213, the second line segment 1212 is located at the middle position 1214 of the outer side surface 121, the first line segment 1211 and the third line segment 1213 are located at the side position 1215 of the outer side surface 121, and the distance from the second line segment 1212 to the central axis X1 is greater than the distance from the first line segment 1211 and the third line segment 1213 to the central axis X1. It can be understood that the first line segment 1211 and the third line segment 1213 are both eccentrically arranged relative to the second line segment 1212. Referring to the figures and the figure, taking the eccentric setting of the first line segment 1211 relative to the second line segment 1212 as an example, the distance from the second line segment 1212 to the central axis X1 is D2, and the distance from the first line segment 1211 to the central axis X1 is D1, and D2 is greater than D1, so that the distance from the edge line of the outer side surface 121 to the central axis X1 gradually decreases from the middle position 1214 to the side position 1215, and the air gap between the permanent magnet 120 and the stator gradually increases from the middle position 1214 to the side position 1215. By changing the distribution law of the air gap, the harmonic content in the magnetic flux density waveform of the air gap magnetic field can be reduced, and the magnetic flux density waveform of the air gap magnetic field tends to a sine wave, so that the back electromotive force waveform of the motor can tend to a sine wave, which can reduce the cogging torque and the torque pulsation of the motor, so that the motor load is more stable when running at high speed, the vibration and noise are lower, the control accuracy is more precise, and the motor performance is more superior and reliable.

[0057] It is understandable that, referring to Figure 8 and Fig. 9 As shown, in some embodiments, the permanent magnet 120 is an axisymmetric structure, and the permanent magnet 120 is symmetrical about the circumferential symmetry line X2, so that the shape of the permanent magnet 120 is relatively regular and it is relatively convenient to manufacture. The circumferential symmetry line X2 is perpendicular to the central axis X1, and the first line segment 1211 and the third line segment 1213 are symmetrically arranged about the circumferential symmetry line X2. Fig. 9Taking the arrow direction in as an example, the circumferential symmetry line X2 extends in the up-down direction, and the first line segment 1211, the second line segment 1212 and the third line segment 1213 are all arc lines with relatively standard shapes and are relatively convenient to manufacture. Since the first line segment 1211 and the third line segment 1213 are symmetrical, the first line segment 1211 and the third line segment 1213 have the same properties, and the first line segment 1211 is mainly used for explanation below. The center P1 of the first line segment 1211 deviates from the central axis X1, the radius of the first line segment 1211 is R1, the center of the third line segment 1213 also deviates from the central axis X1, the angle between the first line segment 1211 and the circumferential symmetry line X2 is α, the center P2 of the second line segment 1212 coincides with the central axis X1 and the circumferential symmetry line X2, and the radius of the second line segment 1212 is R2. Here, a virtual circle E is first defined. The contour of the second line segment 1212 coincides with the edge of the virtual circle E. It can also be understood that the second line segment 1212 is a partial arc length of the virtual circle E. The center P3 of the virtual circle E coincides with the central axis X1. It can also be understood that the center P1 of the second line segment 1212 coincides with the center P3 of the virtual circle E. Since the center P1 of the first line segment 1211 and the center of the third line segment 1213 are both eccentrically arranged relative to the center P2 of the second line segment 1212, the first line segment 1211 and the third line segment 1213 are located within the virtual circle E. It should be noted that the distance D2 from the second line segment 1212 to the central axis X1 is equal to R2. Since the center P2 of the second line segment 1212 coincides with the central axis X1, D2 is unchanged.

[0058] Reference Figure 8 and Fig. 9 As shown, in some embodiments, the center P2 of the second line segment 1212 may also be deviated from the central axis X1, so that the second line segment 1212 is located at the middle position 1214 and the side position 1215 of the outer side surface 121 at the same time. It can also be understood that the second line segment 1212 completely covers the middle position 1214, and part of the second line segment 1212 is located at the side position 1215. In some embodiments, the outer side surface may also only include the second line segment 1212. In this case, the second line segment 1212 completely covers the middle position 1214 and the side position 1215. From the middle to the side of the second line segment 1212, the distance from the second line segment 1212 to the central axis X1 is gradually reduced. At the same time, since the distance from the stator to the central axis X1 is basically unchanged, the air gap between the second line segment 1212 and the stator is gradually increased, achieving a gradual effect, which is conducive to reducing the harmonic content in the magnetic flux density waveform of the air gap magnetic field.

[0059] Not limited to circular arcs, in some embodiments, the first line segment 1211, the second line segment 1212, and the third line segment 1213 may be other types of curves, such as elliptical arcs, parabolas, etc., or a combination of multiple different types of curves. Alternatively, the first line segment 1211, the second line segment 1212, and the third line segment 1213 may be straight line segments, or a combination of multiple non-parallel straight line segments, as long as the distance from the second line segment 1212 to the central axis X1 is greater than the distance from the first line segment 1211 and the third line segment 1213 to the central axis X1.

[0060] Reference Figure 8 and Fig. 9 As shown, on the basis of the above embodiment, the inner side surface 122 of the permanent magnet 120 is a plane, so that the distance from the outer side surface 121 to the inner side surface 122 gradually decreases from the middle position 1214 to the side position 1215. It can also be understood that the thickness of the permanent magnet 120 is gradual. At the middle position 1214, the permanent magnet 120 is thicker, and at the side position 1215, the permanent magnet 120 is thinner. In general, the thickness of the permanent magnet 120 gradually decreases from the middle position 1214 to the side position 1215. Such a design will also affect the air gap magnetic field, which can help reduce the harmonic content in the magnetic flux density waveform of the air gap magnetic field.

[0061] In some embodiments, the inner side surface 122 of the permanent magnet 120 can also be designed to be eccentric. The inner side surface 122 can be a curved surface or a combination of multiple curved surfaces. The edge line of the inner side surface 122 can be a circular arc, an elliptical arc, a parabola or other types of curves. It can also be composed of multiple circular arcs with different radii, or it can be composed of multiple elliptical arcs with different eccentricities, or it can be composed of multiple parabolas with different focal lengths, or it can be composed of multiple circular arcs, elliptical arcs and parabolas. For example, the edge line of the inner side surface 122 is a circular arc, and the edge line of the outer side surface 121 is also a circular arc. The centers of the two circular arcs deviate from the central axis X1, and the centers of the two circular arcs deviate from each other. Alternatively, in some embodiments, the inner side surface 122 may be a combination of multiple non-parallel planes, the multiple planes are eccentrically arranged, and the edge line of the outer side surface 121 may be composed of multiple non-parallel straight line segments, so that the thickness of the permanent magnet 120 is gradual, and the thickness of the permanent magnet 120 gradually decreases from the middle position 1214 to the side position 1215.

[0062] It is understandable that, referring to Fig. 9As shown, in some embodiments, the projected length of the line connecting the center P1 of the first line segment 1211 and the center P2 of the second line segment 1212 on the circumferential symmetry line X2 is h3, and h3 satisfies 25cm≤h3≤30cm. It can also be understood that the line connecting the center P1 of the first line segment 1211 and the center P2 of the second line segment 1212, the angle between the line and the circumferential symmetry line X2 is α, and the length of the line is H, H can be understood as the eccentricity of the center P1, that is, the distance of the center P1 from the central axis X1, and the projected length of the line on the circumferential symmetry line X2 is h3, h3=H*cosα. The size of h3 is related to the size of the eccentricity H. The larger h3 is, the larger the eccentricity H is. By limiting the size of h3, the eccentricity H can be appropriately adjusted, thereby adjusting the degree of gradual change of the air gap. In this embodiment, the eccentricity effect achieved by h3 is better, which is conducive to reducing the harmonic content in the magnetic flux density waveform of the air gap magnetic field.

[0063] It is understandable that, referring to Fig. 9 As shown, in some embodiments, the angle between the line connecting the center P1 of the first line segment 1211 and the center P2 of the second line segment 1212 and the circumferential symmetry line X2 is α, and α satisfies 5°≤α≤7°. α can be understood as the eccentricity angle of the center P1 from the circumferential symmetry line X2. In this embodiment, the eccentricity effect achieved by α is better, which is conducive to reducing the harmonic content in the magnetic flux density waveform of the air gap magnetic field.

[0064] It should be noted that the "central axis" mentioned in the above embodiment refers to an imaginary axis (straight line) that serves as the center of rotation of the rotating body. That is, the central axis is an imaginary axis without any entity. The "circumferential symmetry line" mentioned in the above embodiment refers to an imaginary extension line, which only serves to assist understanding. The "virtual circle" mentioned in the above embodiment refers to an imaginary circle, which only serves to assist understanding. That is, the virtual circle is an imaginary circle without any entity. That is, the virtual circle E is an imaginary line without any entity.

[0065] Reference Fig.10 As shown, the embodiment of the utility model further provides a motor, which includes a housing 400, a stator 200 and a rotor 100 of the above embodiment, and the rotor 100 rotates synchronously with the output shaft 300. Specifically, the motor is a surface mount permanent magnet synchronous motor 1000 (SPMM for short), and the rotor 100 is located at the inner circumference of the stator 200. After adopting the rotor 100 of the above embodiment, the motor has the advantages of low torque pulsation, low working vibration, low working noise, and stable operation. It is particularly important to emphasize that the motor can meet the working conditions of high speed and low torque pulsation, and is suitable for the application scenarios of industrial robots.

[0066] The utility model also provides an industrial robot, which includes the motor of the above embodiment. The industrial robot may be an articulated industrial robot, an autonomous mobile industrial robot, a Cartesian coordinate industrial robot, a spherical coordinate industrial robot, etc. After adopting the motor of the above embodiment, the industrial robot has the advantages of low noise, stable operation, and fast response speed, especially superior performance in high speed and low torque ripple.

[0067] Finally, it should be emphasized that the core point of the utility model is that a groove 1111 is set on the boss portion 111 of the rotor punching 110, which reduces the volume of the boss portion 111, improves the magnetic leakage phenomenon, and makes it difficult for the magnetic flux lines of the permanent magnet 120 to pass through the air gap at the groove 1111. It can also be understood that the magnetic flux lines passing through the boss portion 111 are reduced, and more magnetic flux lines pass through the stator 200, which can reduce the change of the magnetic permeability of the permanent magnet 120, reduce the tooth slot torque, thereby suppressing the torque pulsation, making the motor run more smoothly, and can also improve the anti-demagnetization ability, and the outer side surface 121 of the permanent magnet 120 is also The eccentric design gradually increases the air gap on the outer side surface 121 from the middle position 1214 to the side position 1215. By changing the distribution pattern of the air gap, the harmonic content in the magnetic flux density waveform of the air gap magnetic field can be reduced, so that the magnetic flux density waveform of the air gap magnetic field tends to a sine wave, and the back electromotive force waveform of the motor tends to a sine wave, which can reduce the cogging torque and the torque pulsation of the motor, making the motor load more stable when running at high speed, with lower vibration and noise, more precise control accuracy, and more superior and reliable motor performance. It can meet the working requirements of high speed and low torque pulsation at the same time, and can be specially used in industrial robot scenarios.

[0068] In the description of the present invention, it should be understood that descriptions involving orientation, such as up, down, front, back, left, right, etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0069] In the description of the present utility model, "several" means one or more, "more" means more than two, "greater than", "less than", "exceed" etc. are understood to exclude the number itself, and "above", "below", "within" etc. are understood to include the number itself. If there is a description of "first" or "second", it is only used to distinguish the technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0070] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, connecting, etc. should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0071] The embodiments of the present invention are described in detail above in conjunction with the accompanying drawings, but the present invention is not limited to the above embodiments, and various changes can be made within the knowledge scope of ordinary technicians in the relevant technical field without departing from the purpose of the present invention.

Claims

1. A rotor, characterized in that: include: The rotor punching sheet is provided with a plurality of boss portions located in the radial direction of the rotor punching sheet, and the outer peripheral edge of the rotor punching sheet and two adjacent boss portions are configured to form a limiting groove; A permanent magnet is disposed in the limiting groove, and the movement of the permanent magnet in the circumferential direction is limited by the two boss portions; Wherein, the boss portion is provided with a groove, which is located on the radial outer side of the boss portion and in the circumferential middle part of the boss portion; the rotor punching rotates around the central axis, and the permanent magnet includes an outer side surface located on the radial outer side, and the distance from the circumferential middle part of the outer side surface to the central axis is greater than the distance from the circumferential side part of the outer side surface to the central axis.

2. The rotor according to claim 1, characterized in that The outer surface includes a first line segment, a second line segment and a third line segment which are arranged in sequence along the circumferential direction, the distance from the second line segment to the central axis is greater than the distance from the first line segment and the third line segment to the central axis, the second line segment is an arc, the circle where the arc is located is a virtual circle, and the first line segment and the third line segment are located within the virtual circle.

3. The rotor according to claim 2, characterized in that The first line segment and the third line segment are symmetrically arranged about a circumferential symmetry line, and both the first line segment and the third line segment are arcs and are eccentrically arranged with respect to the second line segment.

4. The rotor according to claim 3, characterized in that The projection length of the line connecting the center of the first line segment and the center of the second line segment on the circumferential symmetry line is h3, satisfying 25cm≤h3≤30cm.

5. The rotor according to claim 3, characterized in that The angle between the line connecting the center of the first line segment and the center of the second line segment and the circumferential symmetry line is α, which satisfies 5°≤α≤7°.

6. The rotor according to claim 1, characterized in that The maximum length from the fitting surface between the boss and the permanent magnet to the radially outer side of the boss is projected on the circumferential symmetry line of the permanent magnet as h1, which satisfies 1mm≤h1≤1.2mm.

7. The rotor according to claim 1, characterized in that The side wall thickness of the groove is d, satisfying 0.5mm≤d≤0.7mm.

8. The rotor according to claim 1, characterized in that The outer periphery of the rotor punching sheet is provided with positioning protrusions, and the permanent magnet abuts against the positioning protrusions, so that a space for accommodating adhesive is formed between the outer periphery of the rotor punching sheet and the permanent magnet.

9. The rotor according to claim 8, characterized in that The radial height of the positioning protrusion is h2, which satisfies 0.1mm≤h2≤0.3mm.

10. A motor, characterized in that A rotor comprising any one of claims 1 to 9.

11. An industrial robot, characterized in that The motor comprising the motor described in claim 10.

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