Servo motor and industrial robot

Abstract

The utility model discloses a servo motor and an industrial robot, the servo motor comprises a housing, a stator assembly and a rotor assembly, the stator assembly is arranged in the housing, the stator assembly comprises a stator iron core and a winding, the stator iron core is fixedly connected with the housing, the winding is wound on the stator iron core, the rotor assembly is rotatably arranged in the stator iron core, and the stator iron core is fixedly connected with the housing. The rotor assembly comprises a rotor iron core and a plurality of magnetic steels, the magnetic steels are installed on the rotor iron core, and the length of the rotor iron core is larger than that of the stator iron core. The maximum outer diameter of the stator core is D1, the minimum inner diameter of the stator core is D2, and 0.65 < = D2 / D1 < = 0.68 is satisfied, so that the ratio of the inner diameter to the outer diameter of the stator core is large, on the premise that the maximum outer diameter of the stator core is kept unchanged, the outer diameter of the rotor core is increased, the rotational inertia of the rotor core is increased, and therefore the rotational inertia of the rotor core is increased under the condition that the increment of the rotational inertia is the same. The length of the rotor core can be shortened, thereby reducing the material cost.

Description

Technical Field

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

[0002] A servo motor is a high-performance motor that can precisely control position, speed, and torque. Compared with traditional servo motors, large-inertia servo motors have higher inertia, can provide greater torque, and have better stability and reliability. In order to obtain a larger moment of inertia, the servo motor in the related art is achieved by increasing the length of the rotor core. However, increasing the length of the rotor core will increase the manufacturing cost 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 provides a servo motor that can increase the moment of inertia of the rotor core while reducing the manufacturing cost.

[0004] The utility model also provides an industrial robot with the servo motor.

[0005] The servo motor of the first embodiment of the utility model comprises a housing having a mounting cavity;

[0006] A stator assembly is arranged in the installation cavity, the stator assembly comprises a stator core and a winding, the stator core is fixedly connected to the housing, the winding is wound around the stator core, and the stator core has an inner cavity;

[0007] A rotor assembly is rotatably disposed in the inner cavity, the rotor assembly comprises a rotor core and a plurality of magnets, the magnets are mounted on the rotor core, and the plurality of magnets are spaced apart in a direction around a rotation axis of the rotor assembly;

[0008] Wherein, the maximum outer diameter of the stator core is D 1 , the minimum inner diameter of the stator core is D 2 , satisfying: 0.65≤D 2 / D 1 ≤0.68;

[0009] Along the direction of the rotation axis, the maximum length of the stator core is L 1 , the maximum length of the rotor core is L 2 , satisfying: L 2 >L 1 .

[0010] The servo motor according to the first embodiment of the utility model has at least the following beneficial effects:

[0011] In the technical solution of the present application, the length of the rotor core is made greater than that of the stator core to increase the length of the rotor core, thereby increasing the moment of inertia of the rotor core. On this basis, the maximum outer diameter of the stator core is D 1 , the minimum inner diameter of the stator core is D 2 , satisfying: 0.65≤D 2 / D 1 ≤0.68, so that the ratio of the inner and outer diameters of the stator core is large. Under the premise of keeping the maximum outer diameter of the stator core unchanged, the minimum inner diameter of the stator core can be increased, so that the maximum outer diameter of the rotor core is increased, the mass of the rotor core is increased, and the moment of inertia of the rotor core is increased. Therefore, under the condition of the same increase in the moment of inertia, the length of the rotor core can be shortened. At the same time, since the maximum outer diameter of the stator core remains unchanged, the sum of the plate amount of the single-layer punching sheets corresponding to the stator core and the rotor core remains unchanged, and shortening the length of the rotor core can reduce the number of punching sheets corresponding to the rotor core, thereby reducing the total plate amount of the stator core and the rotor core, thereby reducing the material cost. In addition, the total length of the servo motor can be shortened, the installation space occupied by the servo motor can be reduced, and it is easy to install.

[0012] According to some embodiments of the present invention, the maximum length of the magnetic steel along the direction of the rotation axis is L 3 , satisfying: L 3 =L 1 .

[0013] According to some embodiments of the utility model, along the direction of the rotation axis, one end of the stator core has a first wall surface, one end of the magnetic steel has a third wall surface, the first wall surface and the third wall surface are located at the same end, and the first wall surface is coplanar with the third wall surface.

[0014] According to some embodiments of the present invention, along the direction of the rotation axis, one end of the rotor core has a second wall surface, the second wall surface and the third wall surface are located at the same end, and the second wall surface and the third wall surface are coplanar.

[0015] According to some embodiments of the present invention, the servo motor further includes a brake assembly, and the brake assembly is located at an end of the rotor assembly facing away from the second wall surface.

[0016] According to some embodiments of the present utility model, the shell includes a limiting step, the limiting step is located on the inner wall of the installation cavity, the limiting step has a fourth wall surface facing the brake assembly, and the first wall surface is in contact with the fourth wall surface.

[0017] According to some embodiments of the present invention, the servo motor also includes a rotating shaft, which is passed through the rotor core and fixedly connected to the rotor core, and the rotating shaft includes a shoulder portion, which has a fifth wall surface facing the brake assembly, and the second wall surface is in contact with the fifth wall surface.

[0018] According to some embodiments of the present invention, the maximum length L of the stator core 1 and the maximum length L of the rotor core 2 Meet: 10mm≤L 2 -L 1 ≤15mm.

[0019] According to some embodiments of the present invention, the maximum length L of the stator core 1 Meet: 30mm≤L 1 ≤50mm.

[0020] According to some embodiments of the present invention, the maximum length L of the rotor core 2 Meet: 45mm≤L 2 ≤65mm.

[0021] According to some embodiments of the present invention, the magnetic steel is located on a side of the rotor core away from the rotation axis.

[0022] The industrial robot of the second embodiment of the utility model comprises the servo motor of the first embodiment of the utility model.

[0023] The industrial robot according to the second embodiment of the utility model has at least the following beneficial effects: compared with the prior art, the servo motor in the industrial robot includes a rotor core and a stator core, so that the length of the rotor core is greater than the length of the stator core, so as to increase the length of the rotor core, thereby increasing the moment of inertia of the rotor core, and on this basis, the maximum outer diameter of the stator core is D 1 , the minimum inner diameter of the stator core is D 2 , satisfying: 0.65≤D 2 / D 1≤0.68, so that the ratio of the inner and outer diameters of the stator core is large. Under the premise of keeping the maximum outer diameter of the stator core unchanged, the minimum inner diameter of the stator core can be increased, so that the maximum outer diameter of the rotor core increases, the mass of the rotor core increases, and then the moment of inertia of the rotor core increases. Therefore, under the condition of the same increase in the moment of inertia, the length of the rotor core can be shortened. At the same time, since the maximum outer diameter of the stator core remains unchanged, the sum of the plate amount of the single-layer punching sheets corresponding to the stator core and the rotor core remains unchanged, and shortening the length of the rotor core can reduce the number of punching sheets corresponding to the rotor core, thereby reducing the total plate amount of the stator core and the rotor core, and thus reducing the material cost. In addition, the total length of the servo motor can be shortened, the installation space occupied by the servo motor can be reduced, and the installation is convenient for installation and reduces the material cost.

[0024] 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

[0025] The present invention is further described below with reference to the accompanying drawings and embodiments, wherein:

[0026] Figure 1 It is a half-section view of a servo motor in an embodiment of the utility model;

[0027] Figure 2 is a cross-sectional view of a rotor assembly and a stator assembly in an embodiment of the utility model;

[0028] Figure 3 is a half-section view of a housing in an embodiment of the utility model;

[0029] Figure 4 yes Figure 1 A in the enlarged view;

[0030] Figure 5 yes Figure 3 The enlarged view of point B in the figure;

[0031] Figure 6 yes Figure 3 The enlarged view of point C in the figure;

[0032] Figure 7 It is a partial view of the rotating shaft in the embodiment of the utility model;

[0033] Figure 8 It is a half-section view of the armature in the embodiment of the utility model.

[0034] Reference numerals:

[0035] Shell 100; mounting cavity 101; limiting step 102; fourth wall 103; rotating shaft 104; shaft shoulder 105; fifth wall 106; shell body 107; end cover 108;

[0036] stator assembly 110; stator core 111; winding 112; ninth wall surface 113; first wall surface 114; first mounting seat 115; second mounting seat 116; plug-in portion 117; sealing groove 118; sealing ring 119;

[0037] Rotor assembly 120; rotor core 121; magnetic steel 122; second wall 123; third wall 124; insulating frame 125; first bearing 126; second bearing 127; retaining spring 128; boss 129; sixth wall 130; retaining groove 131; tenth wall 132; eleventh wall 133;

[0038] Brake assembly 140; armature 141; brake stator 142; seventh wall 143; eighth wall 144;

[0039] Radial X;

[0040] Axis Y. DETAILED DESCRIPTION

[0041] 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.

[0042] 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.

[0043] 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 for the purpose of distinguishing the technical features, and cannot be understood as indicating or implying the relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0044] In the description of the present utility model, unless otherwise clearly defined, terms such as setting, installing, connecting, assembling, and matching 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 utility model based on the specific content of the technical solution.

[0045] The servo motor is a precision control motor and a core component in the servo system. It has the characteristics of high-precision positioning and fast response and is widely used in industrial robots. In the related art, compared with the traditional servo motor, the rotor core of the large inertia servo motor has a higher inertia, which can provide greater torque during continuous operation, maintain a stable rotation speed, and avoid excessive speed fluctuations. Especially in the field of industrial robots, it has better stability and reliability. In order to obtain a larger moment of inertia, in the related art, it is generally achieved by increasing the length of the rotor core. However, increasing the length of the rotor core will lead to an increase in the volume of the motor. At the same time, after the length of the rotor core increases, the amount of punching sheets stacked on the rotor core along the axial direction will increase, resulting in an increase in the manufacturing cost of the servo motor. Correspondingly, the length of the servo motor along the axial direction will also increase, which is not conducive to the spatial layout of the terminal equipment in actual installation.

[0046] To solve the above technical problems, refer to Figure 1 As shown, the first embodiment of the utility model provides a servo motor, specifically, the servo motor includes a housing 100, a stator assembly 110 and a rotor assembly 120, the housing 100 has an installation cavity 101, the stator assembly 110 is arranged in the installation cavity 101 and fixedly installed in the housing 100, the stator assembly 110 has an inner cavity, and the rotor assembly 120 is rotatably arranged in the inner cavity. It can be understood that the housing 100 is coated on the outer periphery of the stator assembly 110 and the rotor assembly 120, so in order to facilitate disassembly and assembly, the housing 100 includes a shell body 107 and an end cover 108 that are detachably connected to each other, the shell body 107 and the end cover 108 both have a cavity, and the cavity of the shell body 107 and the end cover 108 are combined to form the installation cavity 101 of the housing 100, and the shell body 107 and the end cover 108 are fixed by bolt connection.

[0047] It should be noted that, for ease of description and understanding, in the present application, the direction parallel to the rotation axis of the rotor assembly 120 is the axial direction Y, the direction perpendicular to the rotation axis of the rotor assembly 120 is the radial direction X, and the direction surrounding the rotation axis of the rotor assembly 120 is the circumferential direction.

[0048] Reference Figure 1The servo motor includes a rotating shaft 104, a rotor assembly 120 mounted on the rotating shaft 104 and rotating around the axis of the rotating shaft 104, and at the same time, the rotor assembly 120 is located at one end of the rotating shaft 104 close to the shell body 107, and the two ends of the rotating shaft 104 are rotatably connected to the two ends of the shell 100. Specifically, a first bearing 126 and a second bearing 127 are respectively provided at the two ends of the rotating shaft 104, the first bearing 126 is mounted in the shell body 107, and the second bearing 127 is mounted in the end cover 108, and the rotating shaft 104 is rotatably connected to the shell body 107 through the first bearing 126, and is rotatably connected to the end cover 108 through the second bearing 127. Accordingly, referring to Figure 1 and Figure 3 The shell body 107 is provided with a first mounting seat 115 for mounting a first bearing 126, and the end cover 108 is provided with a second mounting seat 116 for mounting a second bearing 127. It can be understood that the first bearing 126 can be fixed in the first mounting seat 115 by interference fit, and the second bearing 127 can be fixed in the second mounting seat 116 by interference fit.

[0049] Reference Figure 5 The end cover 108 is provided with a plug-in portion 117 which can be embedded in the shell body 107. When the shell body 107 and the end cover 108 are connected, the plug-in portion 117 is plugged into the shell body 107, and along the radial direction X, the outer wall of the plug-in portion 117 abuts against the inner wall of the shell body 107, thereby realizing the positioning of the shell body 107 and the end cover 108.

[0050] It is understood that, along the radial direction X, a sealing groove 118 is provided on the outer wall of the plug-in portion 117, and a sealing ring 119 is installed in the sealing groove 118. Along the radial direction X, the outer wall of the sealing ring 119 is pressed against the inner wall of the shell body 107, and the sealing ring 119 and the shell body 107 are interference fit. The sealing ring 119 can be made of materials such as silicone or rubber to achieve the sealing of the shell body 107 and the end cover 108 along the radial direction X, thereby improving the protection capability of the servo motor. It is understood that the plug-in portion 117 can also be provided in the shell body 107, and the plug-in portion 117 is plugged into the end cover 108 during installation, which can also achieve the installation positioning and sealing functions.

[0051] It can be understood that during installation, the shell body 107 and the rotating shaft 104 are positioned through the cooperation of bearings, and the end cover 108 and the rotating shaft 104 are also positioned through bearings. Therefore, along the radial direction X, the gap between the outer wall of the plug-in part 117 and the inner wall of the shell body 107 is larger than the cooperation gap between the shell body 100 and the rotating shaft 104, avoiding interference during installation or causing internal stress in the shell body 100 and the rotating shaft 104.

[0052] Reference Figure 1The servo motor further includes a brake assembly 140. The brake assembly 140 is located on one side of the installation cavity 101 close to the end cover 108. The brake assembly 140 is located in the cavity of the end cover 108. In the technical solution of the present application, the brake assembly 140 uses a permanent magnet brake to achieve braking during shutdown. The brake assembly 140 includes an armature 141 and a brake stator 142. The brake stator 142 is fixedly installed in the end cover 108. The armature 141 is fixed on the rotating shaft 104 and can rotate with the rotating shaft 104. There is a fixed air gap along the axial direction Y between the armature 141 and the brake stator 142. It can be understood that the brake stator 142 has a permanent magnet and a coil. When the servo motor is running, the coil is energized and A magnetic field is generated, and the magnetic field of the coil and the magnetic field of the permanent magnet cancel each other out. Therefore, the permanent magnet has no suction force on the armature 141, and a fixed air gap along the axial direction Y is maintained between the armature 141 and the brake stator 142. The armature 141 rotates with the rotating shaft 104, and the servo motor operates normally. When the servo motor stops, the coil is powered off, and the permanent magnet applies suction force to the armature 141, so that the armature 141 contacts the brake stator 142, and the friction force causes the armature 141 and the rotating shaft 104 to stop rotating, thereby achieving rapid shutdown and meeting the requirements of precise control.

[0053] Reference Figure 7 The shaft 104 is provided with a boss 129, and the boss 129 is provided with a sixth wall surface 130 facing the brake assembly 140. Figure 4 and Figure 8 Along the axial direction Y, the armature 141 has a seventh wall 143 and an eighth wall 144 at both ends. The seventh wall 143 abuts against the sixth wall 130, and the eighth wall 144 abuts against the end surface of the second bearing 127. Therefore, the armature 141 is fixedly installed between the boss 129 and the second bearing 127.

[0054] It can be understood that in actual installation, the brake stator 142 is fixed on the end cover 108 and positioned along the axial direction Y through the second bearing 127. At the same time, the armature 141 is sleeved on the rotating shaft 104, the armature 141 is fixed and the seventh wall 143 of the armature 141 abuts against the sixth wall 130 on the boss 129. Further, the rotating shaft 104 is inserted into the second bearing 127, so that the eighth wall 144 of the armature 141 abuts against the end face of the second bearing 127, thereby realizing the positioning of the rotating shaft 104 along the axial direction Y in the housing 100.

[0055] It can be understood that a slot 131 is provided on the rotating shaft 104, and a retaining spring 128 is inserted into the slot 131. Along the axial direction Y, the side wall of the retaining spring 128 abuts against the end surface of the second bearing 127 facing away from the rotor assembly 120, so that the armature 141 and the slot 131 are clamped on the two end surfaces of the second bearing 127 along the axial direction Y, so as to achieve the fixation of the rotating shaft 104 on the end cover 108 along the axial direction Y during installation, thereby determining the position of the rotor assembly 120 and the brake assembly 140 along the axial direction Y in the housing 100.

[0056] Reference Figure 1 The stator assembly 110 includes a stator core 111 and a winding 112. The stator core 111 is fixedly installed in the housing 100. An insulating frame 125 is installed on the stator core 111. It can be understood that the stator core 111 includes a plurality of stator teeth distributed along the circumferential direction, and a mounting groove is defined between two adjacent stator teeth. The insulating frame 125 is installed on the stator teeth and passes through the mounting groove at both ends of the stator core 111 along the axial direction Y. The winding 112 is wound on the insulating frame 125, and the outer wall of the stator core 111 abuts against the inner wall of the housing 100.

[0057] It can be understood that, along the axial direction Y, the end of the stator core 111 close to the shell body 107 has a first wall surface 114, and the other end of the stator core 111 opposite to the first wall surface 114 is provided with a ninth wall surface 113. Figure 3 and Figure 6 The inner wall of the shell body 107 along the radial direction X has a limiting step 102, the limiting step 102 has a fourth wall surface 103 facing the brake assembly 140, and the first wall surface 114 abuts against the fourth wall surface 103. It can be understood that during actual installation, the stator core 111 is embedded in the shell body 107 along the axial direction Y until the first wall surface 114 of the stator core 111 abuts against the limiting step 102, that is, the positioning of the stator core 111 along the axial direction Y is completed.

[0058] Reference Figure 1The rotor assembly 120 includes a rotor core 121 and a plurality of magnetic steels 122, the magnetic steels 122 are mounted on the rotor core 121, and a plurality of magnetic steels 122 are arranged at intervals on the rotor assembly 120 along the circumferential direction. It can be understood that in the embodiment of the present application, along the radial direction X, the magnetic steel 122 is located on the side of the rotor core 121 away from the rotating shaft 104, and there is an air gap between the outer wall of the magnetic steel 122 along the radial direction X and the inner wall of the stator core 111. The magnetic steel 122 is arranged on the outer cylindrical surface of the rotor core 121 to maximize the use of the magnetic field generated by the magnetic steel 122, so that the path of the magnetic flux directly passing through the air gap is shorter, thereby improving the electromagnetic torque and efficiency of the servo motor, and the magnetic steel 122 is arranged on the outer cylindrical surface of the rotor core 121 to increase the size of the rotor assembly 120 along the radial direction X. When the mass of the rotor assembly 120 is the same, increasing the radial size helps to increase the moment of inertia, thereby meeting the performance requirements of the servo motor. It is understandable that, in other embodiments, the magnetic steel 122 may also be embedded in the rotor core 121 , and a plurality of magnetic steels 122 may be arranged circumferentially on the rotor core 121 .

[0059] It is understandable that, referring to Figure 2 , along the axial direction Y, the rotor core 121 has a second wall surface 123 at one end facing the shell body 107, and a tenth wall surface 132 is provided at the other end of the rotor core 121 opposite to the second wall surface 123. At the same time, one end of the magnetic steel 122 has a third wall surface 124, and the second wall surface 123 and the third wall surface 124 are located at the same end, and the second wall surface 123 and the third wall surface 124 are coplanar. It can be understood that, along the axial direction Y, the magnetic steel 122 has an eleventh wall surface 133 at the other end opposite to the third wall surface 124. It can be understood that the first wall surface 114 and the third wall surface 124 are located at the same end, and the first wall surface 114 and the third wall surface 124 are coplanar, so the first wall surface 114, the second wall surface 123 and the third wall surface 124 are coplanar.

[0060] Reference Figure 7 The shaft 104 includes a shoulder portion 105, and the shoulder portion 105 has a fifth wall 106 facing the rotor core 121. The second wall 123 abuts against the fifth wall 106. It can be understood that since the first wall 114, the second wall 123 and the third wall 124 are coplanar, the fourth wall 103 and the fifth wall 106 are coplanar. During installation, the rotor core 121 is sleeved on the shaft 104 so that the second wall 123 abuts against the fifth wall 106, thereby completing the positioning of the rotor core 121 along the axial direction Y to improve the accuracy and convenience of positioning.

[0061] Reference Figure 2 , along the axial direction Y, the maximum length of the stator core 111 is L 1 , the maximum length of the rotor core 121 is L 2, satisfying: L 2 >L 1 , that is, the maximum length of the rotor core 121 is greater than the maximum length of the stator core 111, so as to increase the length of the rotor core 121, thereby increasing the moment of inertia of the rotor core 121, so that the moment of inertia of the rotor core 121 meets the performance requirements of the servo motor.

[0062] Reference Figure 2 , along the radial direction X, the maximum outer diameter of the stator core 111 is D 1 , the minimum inner diameter of the stator core 111 is D 2 , satisfying: 0.65≤D 2 / D 1 ≤0.68, so that the ratio of the inner and outer diameters of the stator core 111 is large, that is, the maximum outer diameter D of the stator core 111 can be maintained. 1 Increase the minimum inner diameter D while keeping the same 2 The size of the rotor core 121 increases the outer diameter of the rotor core 121, thereby increasing the mass of the rotor core 121 and thus increasing the moment of inertia of the rotor core 121. 2 Greater than the maximum length L of the stator core 111 1 , which can further improve the mass of the rotor core 121 , thereby effectively increasing the moment of inertia of the rotor core 121 .

[0063] Understandably, when D 2 / D 1 When <0.65, the minimum inner diameter D of the stator core 111 2 The outer diameter of the rotor core 121 is too small, and the increase in the inertia of the rotor core 121 is insufficient, so that the performance requirements of the servo motor cannot be met. If the inertia of the rotor core 121 reaches the ideal value, the maximum length of the rotor core 121 needs to be increased, which will increase the manufacturing cost. 2 / D 1 >0.68, the minimum inner diameter D of the stator core 111 2 The larger the diameter D of the stator core 111, the more effective it is to increase the moment of inertia of the rotor core 121. When the increase in the moment of inertia is the same, the maximum length of the rotor core 121 can be shortened and the manufacturing cost can be reduced. However, the maximum outer diameter D of the stator core 111 is 1 Under the premise of being unchanged, the ratio of the inner and outer diameters of the stator core 111 will be too large, which will reduce the effective magnetic circuit area and make the magnetic flux saturation of the stator core 111 too high, which also cannot meet the performance requirements of the servo motor. 2 / D 1 ≤0.68, which can meet the rotational inertia requirements of the servo motor, and can reduce manufacturing costs and shorten the installation space of the servo motor.

[0064] It is understandable that the stator core 111 and the rotor core 121 are formed by stacking a number of punching sheets along the axial direction Y, and in the actual production process, the punching sheets of the stator core 111 and the rotor core 121 can be made by stamping or cutting the same blank. When the maximum outer diameter of the rotor core 121 increases, under the condition of the same increase in the moment of inertia, compared with the current method of increasing the inertia by only increasing the length of the rotor core 121, the technical solution of the present application can shorten the length of the rotor core 121. Since the maximum outer diameter of the stator core 111 remains unchanged, the sum of the plate amount of the single-layer punching sheets corresponding to the stator core 111 and the rotor core 121 remains unchanged, and shortening the length of the rotor core 121 can reduce the number of punching sheets corresponding to the rotor core 121, thereby reducing the total plate amount of the stator core 111 and the rotor core 121, and thus reducing the material cost. In addition, the total length of the servo motor can be shortened, and the installation space occupied by the servo motor can be reduced, which is convenient for installation.

[0065] It can be understood that in actual measurement, the maximum outer diameter D of the stator core 111 along the radial direction X is 1 and minimum inner diameter D 2 The projection shape of the outer peripheral wall of the stator core 111 on the projection plane perpendicular to the axial direction Y includes a circle or a polygon. When the projection shape is a circle, the maximum outer diameter D of the stator core 111 is 1 is twice the distance between the outer wall and the rotation axis along the radial direction X; when the projected shape is a polygon, the maximum outer diameter D of the stator core 111 1 is the diameter of the circumcircle of the polygon.

[0066] Accordingly, on the projection plane perpendicular to the axial direction Y, the projection shape of the inner peripheral wall of the stator core 111 includes a circle or a polygon. When the projection shape is a circle, the minimum inner diameter D of the stator core 111 is 2 is twice the distance between the inner wall and the rotation axis along the radial direction X; when the projection shape is a polygon, the minimum inner diameter D of the stator core 111 is 2 is the diameter of the inscribed circle of the polygon.

[0067] It can be understood that, along the axial direction Y, the maximum distance between the first wall surface 114 and the ninth wall surface 113 on the stator core 111 measured by a vernier caliper is the maximum length L of the stator core 111. 1 Similarly, along the axial direction Y, the maximum distance between the second wall surface 123 and the tenth wall surface 132 on the rotor core 121 measured by a vernier caliper is the maximum length of the stator core 111 .

[0068] It can be understood that when the first wall surface 114 and the third wall surface 124 are coplanar, L 2>L 1 Specifically, in actual installation, there is a gap between the tenth wall 132 and the brake assembly 140. 2 >L 1 , the gap between the ninth wall 113 and the brake assembly 140 can be increased, thereby increasing the distance between the stator assembly 110 and the brake assembly 140. It should be noted that in actual use, in order to ensure good braking performance, the maximum outer diameters of the armature 141 and the brake stator 142 are both greater than the maximum outer diameter of the rotor core 121. Therefore, there is a risk of interference between the stator assembly 110 and the brake assembly 140 in the housing 100. It is understandable that if the ninth wall 113 and the tenth wall 132 are coplanar, in order to avoid interference between the brake assembly 140 and the stator assembly 110, it is necessary to increase the distance between the brake assembly 140 and the stator assembly 110, thereby increasing the length of the servo motor along the axial direction Y, which in turn increases the manufacturing cost of the servo motor. Therefore, when L 2 >L 1 When the stator assembly 110 and the brake assembly 140 are connected, the distance between the stator assembly 110 and the brake assembly 140 can be increased, thereby effectively avoiding interference between the stator assembly 110 and the brake assembly 140.

[0069] Define the maximum length of the magnetic steel 122 as L 3 , satisfying: L 3 =L 1 , that is, along the axial direction Y, the maximum length L of the magnetic steel 122 3 The maximum length L of the stator core 111 1 At the same time, since the first wall surface 114 and the third wall surface 124 are coplanar, in the radial direction X, the wall surfaces of the magnet 122 are all directly opposite to the inner circumferential wall of the stator core 111, so that the magnetic field generated by the magnet 122 can be utilized to the maximum extent, thereby improving the electromagnetic torque output of the motor, and helping to reduce the magnetic leakage at the end of the magnetic circuit, ensuring that most of the magnetic flux passes through the stator winding 112, thereby improving the efficiency of the motor.

[0070] It can be understood that, along the axial direction Y, the maximum distance between the third wall surface 124 and the eleventh wall surface 133 on the magnetic steel 122 measured by a vernier caliper is the maximum length L of the magnetic steel 122 3 .

[0071] It is understandable that the maximum length L of the stator core 111 1 and the maximum length L of the rotor core 121 2 Meet: 10mm≤L 2 -L 1 ≤15mm. It is understandable that L 1 To determine the value, when L 2 -L 1When L is less than 10 mm, the maximum length of the rotor core 121 is too small, resulting in insufficient mass of the rotor core 121 and insufficient moment of inertia of the rotor core 121. If the preset moment of inertia is to be maintained, the maximum outer diameter of the rotor core 121 will continue to increase, which will cause the minimum inner diameter of the stator core 111 to increase. Under the premise that the maximum outer diameter of the stator core 111 remains unchanged, the ratio of the inner and outer diameters of the stator core 111 will increase and exceed a reasonable value, thereby reducing the effective magnetic circuit area, failing to meet the performance requirements, and causing the structural strength of the stator core 111 to decrease. When L is less than 10 mm, the maximum outer diameter of the rotor core 121 will continue to increase, which will cause the minimum inner diameter of the stator core 111 to increase. Under the premise that the maximum outer diameter of the stator core 111 remains unchanged, the ratio of the inner and outer diameters of the stator core 111 will increase and exceed a reasonable value, thereby reducing the effective magnetic circuit area, failing to meet the performance requirements, and causing the structural strength of the stator core 111 to decrease. 2 -L 1 When L is greater than 15 mm, the maximum length of the rotor core 121 is too large, which can meet the moment of inertia requirement of the rotor core 121, but will increase the manufacturing cost of the rotor core 121 and increase the length of the servo motor along the axial direction Y, which is not conducive to the cost control and spatial layout of the servo motor. 2 -L 1 ≤15mm, which can meet the rotational inertia requirements of the servo motor, while reducing manufacturing costs and shrinking the installation space occupied by the servo motor.

[0072] It is understandable that the maximum length L of the stator core 111 1 Meet: 30mm≤L 1 ≤50mm. It is understandable that when L 1 When L is less than 30 mm, the length of the stator core 111 is too small, so that the magnetic field generated by the magnetic steel 122 is insufficiently utilized, which will cause the performance of the servo motor to deteriorate and fail to meet the use requirements; when L 1 When L>50mm, the manufacturing cost of the stator core 111 will increase. Therefore, 30mm≤L 1 ≤50mm, which can meet the performance requirements of the servo motor and reduce the manufacturing cost.

[0073] It is understandable that the maximum length L of the rotor core 121 2 Meet: 45mm≤L 2 ≤65mm. It is understandable that when L 2 When L is less than 45 mm, the maximum length of the rotor core 121 is too small, resulting in insufficient mass of the rotor core 121 and insufficient moment of inertia of the rotor core 121. If the preset moment of inertia is to be maintained, the maximum outer diameter of the rotor core 121 will continue to increase, which will cause the minimum inner diameter of the stator core 111 to increase. Under the premise that the maximum outer diameter of the stator core 111 remains unchanged, the ratio of the inner and outer diameters of the stator core 111 will increase and exceed the reasonable value, and the effective magnetic circuit area will be reduced, thereby failing to meet the performance requirements of the servo motor. On the other hand, when L 2When L is greater than 65 mm, the maximum length of the rotor core 121 is larger, which can meet the moment of inertia requirement of the rotor core 121, but the manufacturing cost of the rotor core 121 will increase, and the length of the servo motor along the axial direction Y will increase, resulting in an increase in the cost of the servo motor, and in actual installation, it is not conducive to the spatial layout of the terminal equipment. 2 ≤65mm, which can meet the motor's rotational inertia requirements, while reducing manufacturing costs and shrinking the installation space occupied by the servo motor.

[0074] The industrial robot of the second embodiment of the utility model includes the servo motor of the first embodiment of the utility model. Since the industrial robot adopts all the technical solutions of the servo motor of the above embodiment, it has at least all the beneficial effects brought by the technical solutions of the above embodiment.

[0075] 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 servo motor, characterized in that: include: A housing having a mounting cavity; A stator assembly is arranged in the installation cavity, the stator assembly comprises a stator core and a winding, the stator core is fixedly connected to the housing, the winding is wound around the stator core, and the stator core has an inner cavity; A rotor assembly is rotatably disposed in the inner cavity, the rotor assembly comprises a rotor core and a plurality of magnets, the magnets are mounted on the rotor core, and the plurality of magnets are spaced apart in a direction around a rotation axis of the rotor assembly; The maximum outer diameter of the stator core is D1, and the minimum inner diameter of the stator core is D2, which satisfies: 0.65≤D2 / D1≤0.68; Along the direction of the rotation axis, the maximum length of the stator core is L1, and the maximum length of the rotor core is L2, satisfying: L2>L1.

2. The servo motor according to claim 1, characterized in that: Along the direction of the rotation axis, the maximum length of the magnetic steel is L3, satisfying: L3 = L1.

3. The servo motor according to claim 2, characterized in that: Along the direction of the rotation axis, one end of the stator core has a first wall surface, and one end of the magnetic steel has a third wall surface. The first wall surface and the third wall surface are located at the same end, and the first wall surface is coplanar with the third wall surface.

4. The servo motor according to claim 3, characterized in that: One end of the rotor core has a second wall surface along the direction of the rotation axis. The second wall surface is located at the same end as the third wall surface, and the second wall surface is coplanar with the third wall surface.

5. The servo motor according to claim 4, characterized in that: The servo motor further comprises a brake assembly, wherein the brake assembly is located at an end of the rotor assembly away from the second wall surface.

6. The servo motor according to claim 5, characterized in that: The housing comprises a limiting step, the limiting step is located on the inner wall of the mounting cavity, the limiting step has a fourth wall surface facing the brake assembly, and the first wall surface abuts against the fourth wall surface.

7. The servo motor according to claim 5, characterized in that: The servo motor also includes a rotating shaft, which is passed through the rotor core and fixedly connected to the rotor core. The rotating shaft includes a shoulder portion, and the shoulder portion has a fifth wall surface facing the brake assembly, and the second wall surface abuts against the fifth wall surface.

8. The servo motor according to claim 1, characterized in that: The maximum length L1 of the stator core and the maximum length L2 of the rotor core satisfy: 10 mm ≤ L2 - L1 ≤ 15 mm.

9. The servo motor according to claim 8, characterized in that: The maximum length L1 of the stator core satisfies: 30 mm ≤ L1 ≤ 50 mm.

10. The servo motor according to claim 8, characterized in that: The maximum length L2 of the rotor core satisfies: 45mm≤L2≤65mm.

11. The servo motor according to claim 1, characterized in that: The magnetic steel is located at a side of the rotor core away from the rotation axis.

12. An industrial robot, characterized in that Comprising a servo motor as claimed in any one of claims 1 to 11.

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