CN117728607A - Rotor assembly, direct current motor and robot - Google Patents

Abstract

The application relates to a rotor subassembly, direct current motor and robot, the rotor subassembly includes: the device comprises a limiting piece, a first magnet and a second magnet. One side of the limiting piece is provided with a plurality of limiting grooves which are concavely arranged along the direction from one side to the other side of the limiting piece. The limiting grooves are distributed along the circumferential direction, and adjacent limiting grooves are arranged at intervals. The plurality of first magnets are distributed along the circumferential direction. One end of the first magnet is accommodated in the limiting groove. The plurality of second magnets are distributed along the circumferential direction. The second magnets are arranged between two adjacent first magnets. The maximum distance between the first magnet and the adjacent second magnet is the sum of two negative value tolerances, so that the negative value accumulation tolerance with an excessive absolute value is avoided, and a splicing gap with a larger distance is prevented from being formed between the first magnet and the second magnet. The second magnet can be placed between the two first magnets by means of the residual space of the first magnets, so that the overall gap is reduced, and the pole arc coefficient of the tube is close to 1.

Description

Rotor assembly, direct current motor and robot

Technical Field

The application relates to the technical field of direct current motors, in particular to a rotor assembly, a direct current motor and a robot.

Background

Robots are machine devices that perform work semi-autonomously or fully automatically. It can accept human command, run pre-programmed program and act according to the principle set by artificial intelligence technology. Its task is to assist or replace the work of humans. It is a product of advanced integrated control theory, mechano-electronics, computer, material and bionics, and has important application in the fields of industry, medicine, agriculture, service industry, architecture industry and even military.

Part of robots need to move by using a wheel body, and the wheel body is driven by a direct current motor. In addition, some robots utilize a direct current motor to drive the movement of the joint structure. Therefore, the dc motor has a large role in the robot.

The rotor of a part of the direct current motor comprises a rotor housing and a plurality of magnets which are distributed along the circumferential direction. The pole arc coefficient is a parameter representing the circumferential arrangement characteristic of a plurality of magnets. When the pole arc coefficient is 1, the magnetic flux of the direct current motor is maximum, and the torque density is highest. However, the pole arc coefficient is perfectly achievable only in an ideal state where all magnet manufacturing tolerances are zero. In the case where there is a manufacturing tolerance, if the cumulative tolerance is greater than zero, the adjacent magnets form an interference fit despite the pole arc coefficient of 1, resulting in the magnets possibly being crushed. If the accumulated tolerance is smaller than zero, most adjacent magnets are closely connected due to magnetic force, and a splicing gap with larger space is formed between the two magnets, so that the magnetic poles of the rotor are uneven due to the splicing gap, and noise is generated when the motor operates.

Disclosure of Invention

Accordingly, it is necessary to provide a rotor assembly, a dc motor, and a robot, which are directed to the problem that the rotor magnet is easily subjected to interference fit or a large-pitch splice gap is formed when the magnet has a manufacturing tolerance.

A rotor assembly, comprising:

the limiting piece is provided with a plurality of limiting grooves on one side; the limiting groove is concavely arranged along the direction from one side to the other side of the limiting piece; the limiting grooves are distributed along the circumferential direction; the adjacent limit grooves are arranged at intervals;

the first magnets are distributed along the circumferential direction; one end of the first magnet is accommodated in the limit groove; and

The second magnets are distributed along the circumferential direction, and the second magnets are arranged between two adjacent first magnets.

The rotor assembly comprises a first magnet and a second magnet which are distributed along the circumferential direction. The width of one end of the first magnet is not greater than the width of the limit groove along the circumferential direction, so that one end of the first magnet can be smoothly placed into the limit groove and is prevented from being extruded by the limit piece. Because the relative positions among the limiting grooves on the limiting piece are fixed, after one end of the first magnet is contained in the limiting groove, the first magnets are positioned at stable relative positions. Since the second magnet is located between the two first magnets, the circumferential movement range of the second magnet is limited by the first magnets. Under the condition that the first magnet and the second magnet are limited, all the first magnet and the second magnet are prevented from being completely and closely connected due to magnetic force, the maximum distance between the first magnet and the adjacent second magnet is the sum of two negative value tolerances, the negative value accumulation tolerance with overlarge absolute value is prevented, and a splicing gap with larger distance between the first magnet and the second magnet is prevented from being formed. In addition, since the adjacent first magnets and the second magnets are in the space communicating in the circumferential direction, when there is a positive tolerance in the width of the second magnet and a negative tolerance in the width of at least one adjacent first magnet, the second magnet can be interposed between the two first magnets by the remaining space of the first magnet, thereby reducing the overall gap, and making the pipe pole arc coefficient close to 1. Because the opposite manufacturing tolerance between the adjacent first magnet and the second magnet is utilized, the first magnet or the second magnet cannot be cracked due to excessive extrusion force.

In one embodiment, the length of the second magnet is shorter than the length of the first magnet; the length difference between the second magnet and the first magnet corresponds to the concave depth of the limit groove.

In one embodiment, the length of the first magnet is identical to the length of the second magnet; the width of the first magnet is consistent with the width of the second magnet.

In one embodiment, the device further comprises a shell, wherein the limiting piece is accommodated in the shell; the outer peripheral surface of the limiting piece is propped against the inner peripheral surface of the shell, or the limiting piece and the shell are integrally arranged.

In one embodiment, the housing is in a semi-open configuration; the bottom surface of the limiting groove faces to the opening side of the shell.

A rotor assembly, comprising:

one surface of the end cover is provided with a limit groove; the limiting grooves are distributed at intervals along the circumferential direction;

the shell wall is communicated with the two ends and one end of the shell wall is connected with the end cover;

a first magnet housed within the housing wall; a plurality of first magnets are distributed along the circumferential direction; one end of the first magnet is inserted into the limit groove; and

A second magnet housed within the housing wall; the second magnets are distributed along the circumferential direction, and the second magnets are arranged between two adjacent first magnets.

A rotor assembly comprising;

the shell is provided with a first radial groove on the inner peripheral side; the plurality of first radial grooves are distributed at intervals along the inner circumference of the shell; the inner peripheral side of the shell is also provided with a second radial groove; the second radial grooves are arranged between two adjacent first radial grooves, and the two first radial grooves are communicated through the second radial grooves; the length of the first radial groove along the axial direction of the shell is greater than the length of the second radial groove;

a first magnet accommodated in the first radial groove; the length of the first magnet is greater than the length of the second radial groove; and

A second magnet accommodated in the second radial groove; the length of the second magnet is not greater than the length of the second radial groove.

A rotor assembly, comprising:

the inner peripheral side of the positioning piece is provided with a third radial groove; the third radial grooves are distributed at intervals along the inner circumference of the positioning piece;

the first magnets are distributed along the inner circumference of the positioning piece; the first magnet is accommodated in the third radial groove; the radial thickness of the first magnet is greater than the radial depth of the third radial groove; and

The second magnets are distributed along the inner circumference of the positioning piece; the second magnets are arranged between the adjacent first magnets along the inner circumference of the positioning piece.

A DC motor includes a rotor assembly.

A robot includes a DC motor.

Drawings

Fig. 1 is a schematic perspective view of a dc motor according to an embodiment of the present application.

Fig. 2 is a partial schematic view of the dc motor shown in fig. 1.

Fig. 3 is an exploded view of the dc motor shown in fig. 2.

Fig. 4 is an enlarged view of a portion a of the dc motor shown in fig. 3.

Fig. 5 is a perspective view of a rotor assembly according to an embodiment of the present application.

FIG. 6 is an exploded schematic view of the rotor assembly shown in FIG. 5.

Fig. 7 is a perspective view of a rotor assembly according to another embodiment of the present application.

Fig. 8 is a perspective view of a rotor assembly according to yet another embodiment of the present application.

Fig. 9 is a perspective view of a rotor assembly according to yet another embodiment of the present application.

Reference numerals: 100. a DC motor; 20. a stator assembly; 21. a magnetic conductive member; 30. a rotor assembly; 31. a limiting piece; 311. a through groove; 312. a limit groove; 32. a first magnet; 33. a second magnet; 34. a housing; 341. a first radial groove; 342. a second radial groove; 35. an end cap; 351. a bump; 36. a shell wall; 37. a positioning piece; 371. a third radial groove; 38. a bottom cover; 40. a shaft lever; 41. a bearing member; 50. a stator base; 60. and a control module.

Detailed Description

In order to make the above objects, features and advantages of the present application more comprehensible, embodiments accompanied with figures are described in detail below. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application. This application is, however, susceptible of embodiment in many other forms than those described herein and similar modifications can be made by those skilled in the art without departing from the spirit of the application, and therefore the application is not to be limited to the specific embodiments disclosed below.

In the description of the present application, it should be understood that, if there are terms such as "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., these terms refer to the orientation or positional relationship based on the drawings, which are merely for convenience of description and simplification of description, and do not indicate or imply that the apparatus or element referred to must have a specific orientation, be configured and operated in a specific orientation, and therefore should not be construed as limiting the present application.

Furthermore, the terms "first," "second," and the like, if any, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In the description of the present application, the terms "plurality" and "a plurality" if any, mean at least two, such as two, three, etc., unless specifically defined otherwise.

In this application, unless explicitly stated and limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly. For example, the two parts can be fixedly connected, detachably connected or integrated; can be mechanically or electrically connected; either directly or indirectly, through intermediaries, or both, may be in communication with each other or in interaction with each other, unless expressly defined otherwise. The specific meaning of the terms in this application will be understood by those of ordinary skill in the art as the case may be.

In this application, unless expressly stated or limited otherwise, the meaning of a first feature being "on" or "off" a second feature, and the like, is that the first and second features are either directly in contact or indirectly through intervening media. Moreover, a first feature being "above," "over" and "on" a second feature may be a first feature being directly above or obliquely above the second feature, or simply indicating that the first feature is higher in level than the second feature. The first feature being "under", "below" and "beneath" the second feature may be the first feature being directly under or obliquely under the second feature, or simply indicating that the first feature is less level than the second feature.

It will be understood that if an element is referred to as being "fixed" or "disposed" on another element, it can be directly on the other element or intervening elements may also be present. If an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and the like as used herein, if any, are for descriptive purposes only and do not represent a unique embodiment.

The following describes the technical scheme provided by the embodiment of the application with reference to the accompanying drawings.

The application provides a robot.

In some embodiments, as shown in connection with fig. 1, the robot has a wheel and a dc motor 100. A transmission fit capable of driving the wheel body to rotate around the axle center is formed between the output end of the direct current motor 100 and the wheel body. The robot can move between different positions or can move at a set speed through the rotation of the wheel body.

In some embodiments, the robot has a joint structure and a dc motor 100. The two movable parts of the robot are connected through a joint structure. The dc motor 100 is disposed on the joint structure and is used to drive two connected parts of the joint structure to rotate relatively, so that the relative angle between the movable parts is changed. In some embodiments, the movable component is a lever arm.

As shown in connection with fig. 1 to 9, the present application also provides a dc motor 100.

In some embodiments, as shown in connection with fig. 1-3, a dc motor 100 includes a stator assembly 20 and a rotor assembly 30. The stator assembly 20 is capable of generating an alternating magnetic field. The rotor assembly 30 has magnetism, and the rotor assembly 30 rotates relative to the stator assembly 20 under the guidance of an alternating magnetic field.

In some embodiments, as shown in connection with fig. 2 and 3, the stator assembly 20 includes a stator winding and a magnetically permeable member 21. The stator winding is wound on the magnetic conductive member 21. The magnetic conductive member 21 guides the magnetic field generated by the stator winding to the outer circumference of the magnetic conductive member 21. The current flowing in the stator winding changes according to a rule, so that an alternating magnetic field is generated. Specifically, the magnetic conductive member 21 is made of a high magnetic permeability material. In some embodiments, the magnetically permeable member 21 is a core.

In some embodiments, as shown in fig. 2 and 3, the dc motor 100 further includes a shaft 40 and a stator base 50. The rotor assembly 30 is connected to a shaft 40. The rotor assembly 30 is connected to the stator housing 50. Further, the direct current motor 100 further includes a bearing member 41. In some embodiments, the bearing member 41 is disposed radially between the shaft 40 and the stator mount 50. In another embodiment, the bearing member 41 is radially disposed between the stator housing 50 and the rotor assembly 30.

In some embodiments, as shown in connection with fig. 2 and 3, the dc motor 100 further includes a control module 60. The control module 60 is used to control the change in the direction of current flow of the stator assembly 20. Specifically, the control module 60 includes a PCB circuit board. In some embodiments, the control module 60 is disposed within the stator housing 50.

In some embodiments, as shown in connection with fig. 2 and 3, the control module 60 further includes a sensing unit. The sensing unit is used to identify the number of turns of the rotor assembly 30 relative to the stator windings, or to identify the relative angle between the rotor assembly 30 and the stator windings. In some embodiments, the sensing unit is connected to the shaft 40 in part and to the PCB circuit board in part. In some embodiments, the sensing unit performs the detection operation based on the hall sensing principle.

As shown in connection with fig. 2-9, the present application also provides a rotor assembly 30.

In some embodiments, as shown in connection with fig. 2-3, the rotor assembly 30 includes: end cap 35, shell wall 36, first magnet 32, and second magnet 33. One side of the end cap 35 is provided with a limit slot 312. The plurality of limiting grooves 312 are circumferentially spaced apart. The shell wall 36 is disposed in communication at two ends, and one end of the shell wall 36 is connected to the end cap 35. The first magnet 32 is housed within the housing wall 36. A plurality of first magnets 32 are circumferentially distributed. One end of the first magnet 32 is inserted into the limiting groove 312. The second magnet 33 is accommodated in the case wall 36. A plurality of second magnets 33 are distributed in the circumferential direction. The second magnet 33 is disposed between two adjacent first magnets 32.

Specifically, the first magnet 32 and the second magnet 33 are distributed together circumferentially around the center of the end cover 35. The width of one end of the first magnet 32 is not greater than the width of the limit groove 312 along the circumferential direction, so that one end of the first magnet 32 can be smoothly placed into the limit groove 312 and avoid being extruded. Because the relative positions of the limiting grooves 312 on the end cover 35 are fixed, after one end of the first magnet 32 is inserted into the limiting groove 312, the first magnets 32 are in stable relative positions. Since the second magnet 33 is located between the two first magnets 32, the circumferential movement of the second magnet 33 is limited by the first magnets 32. Under the condition that the first magnet 32 and the second magnet 33 are limited, all the first magnet 32 and the second magnet 33 are prevented from being completely and closely connected due to magnetic force, the maximum distance between the first magnet 32 and the adjacent second magnet 33 is the sum of two negative value tolerances, the occurrence of negative value accumulation tolerance with overlarge absolute value is avoided, and a splicing gap with larger distance between the first magnet 32 and the second magnet 33 is prevented. In addition, since the adjacent first magnets 32 and second magnets 33 are in the space communicating in the circumferential direction, when there is a positive tolerance in the width of the second magnet 33 and a negative tolerance in the width of at least one adjacent first magnet 32, the second magnet 33 can be interposed between the two first magnets 32 with the remaining space of the first magnet 32, reducing the overall gap, and making the polar arc coefficient close to 1. Since the manufacturing tolerance opposite between the adjacent first magnet 32 and second magnet 33 is utilized, the first magnet 32 or second magnet 33 is not caused to collapse due to an excessive pressing force.

In particular, negative tolerances are understood to be manufacturing tolerances smaller than zero. Positive tolerances are understood to be manufacturing tolerances greater than zero. Negative tolerances occur when the actual size is smaller than the standard size. Positive tolerances occur when the actual size is greater than the standard size.

In one hypothetical case, the rotor assembly 30 includes 20 first magnets 32 and 20 second magnets 33. If negative tolerance of-0.05 mm exists in each of the first magnets 32 and each of the second magnets 33, a splice gap of 2mm width is formed between one of the first magnets 32 and one of the second magnets 33 due to the close connection of the first magnets 32 and the second magnets 33 under the action of magnetic force in the conventional art. In this application, since the first magnet 32 is defined in the limit groove 312, in the case that the width of the limit groove 312 is a standard value, the maximum gap between the first magnet 32 and the adjacent second magnet 33 is 0.1mm or 0.15mm, so that the maximum gap between the first magnet 32 and the second magnet 33 is effectively controlled, and the assembly tolerance is reduced.

In some embodiments, a first magnet 32 is disposed diametrically opposite another first magnet 32. The second magnet 33 is disposed diametrically opposite to the other second magnet 33. In some embodiments, the first magnet 32 or the second magnet 33 is made of steel.

In some embodiments, as shown in connection with fig. 2, the magnetically permeable member 21 is housed within the housing wall 36. Further, as shown in connection with fig. 2 and 3, the rotor assembly 30 also includes a bottom cover 38. The shell wall 36 has one end connected to the end cover 35 and the other end connected to the bottom cover 38 to form an enclosed space capable of accommodating the magnetic conductive member 21.

In some embodiments, as shown in connection with fig. 1 and 2, the housing wall 36 is cylindrically configured. The first magnet 32 and the second magnet 33 are bonded to the inner peripheral surface of the case wall 36. Specifically, the first magnet 32 and the second magnet 33 are bonded to the inner peripheral surface of the case wall 36 by an adhesive material, respectively, thereby ensuring that the first magnet 32 and the second magnet 33 are stably arranged in the circumferential direction.

In some embodiments, the limit groove 312 is recessed relative to a surface of one face of the end cap 35.

In other embodiments, as shown in connection with fig. 3 and 4, a tab 351 is attached to one side of the end cap 35. The projection 351 is provided to protrude from a surface of one face of the end cap 35. The plurality of bumps 351 are circumferentially spaced apart. The limiting grooves 312 are formed between adjacent protruding blocks 351.

In some embodiments, the bump 351 is integrally provided with the end cap 35, thereby improving connection stability between the bump 351 and the end cap 35. Further, the protrusions 351 are distributed along the inner circumference of one side of the end cap 35, thereby improving the compactness of the rotor assembly 30. In some embodiments, the plurality of bumps 351 are in abutment with the inner peripheral surface of the housing wall 36. In some embodiments, the tab 351 is an interference fit with the inner peripheral surface of the housing wall 36 to maintain a fixed relative position between the end cap 35 and the housing 34.

In some embodiments, as shown in connection with fig. 5 and 6, the rotor assembly 30 includes: a stopper 31, a first magnet 32 and a second magnet 33. One side of the limiting piece 31 is provided with a plurality of limiting grooves 312, and the limiting grooves 312 are concavely arranged along the direction from one side to the other side of the limiting piece 31. The plurality of limiting grooves 312 are distributed along the circumferential direction, and adjacent limiting grooves 312 are arranged at intervals. A plurality of first magnets 32 are circumferentially distributed. One end of the first magnet 32 is accommodated in the limiting groove 312. A plurality of second magnets 33 are distributed in the circumferential direction. The second magnet 33 is disposed between two adjacent first magnets 32.

Specifically, the first magnet 32 and the second magnet 33 are distributed together in the circumferential direction. The width of one end of the first magnet 32 is not greater than the width of the limiting groove 312 along the circumferential direction, so that one end of the first magnet 32 can be smoothly placed into the limiting groove 312 and is prevented from being extruded by the limiting piece 31. Because the relative positions of the limiting grooves 312 on the limiting piece 31 are fixed, after one end of the first magnet 32 is accommodated in the limiting groove 312, the first magnets 32 are in stable relative positions. Since the second magnet 33 is located between the two first magnets 32, the range of circumferential movement of the second magnet 33 is limited by the first magnets 32. Under the condition that the first magnet 32 and the second magnet 33 are limited, all the first magnet 32 and the second magnet 33 are prevented from being completely and closely connected due to magnetic force, the maximum distance between the first magnet 32 and the adjacent second magnet 33 is the sum of two negative value tolerances, the occurrence of negative value accumulation tolerance with overlarge absolute value is avoided, and a splicing gap with larger distance between the first magnet 32 and the second magnet 33 is prevented. In addition, since the adjacent first magnets 32 and second magnets 33 are in a space communicating in the circumferential direction, when there is a positive tolerance in the width of the second magnet 33 and a negative tolerance in the width of at least one first magnet 32 adjacent thereto, the second magnet 33 can be interposed between the two first magnets 32 by the remaining space of the first magnet 32, thereby reducing the overall gap, and making the pipe pole arc coefficient close to 1. Since the manufacturing tolerance opposite between the adjacent first magnet 32 and second magnet 33 is utilized, the first magnet 32 or second magnet 33 is not caused to collapse due to an excessive pressing force.

In some embodiments, as shown in fig. 5 and 6, the length of the second magnet 33 is shorter than the length of the first magnet 32, and the difference in length between the second magnet 33 and the first magnet 32 corresponds to the recess depth of the limiting groove 312. Specifically, since the length difference between the second magnet 33 and the first magnet 32 corresponds to the recess depth of the limiting groove 312, the end of the first magnet 32 away from the limiting member 31 and the end of the second magnet 33 away from the limiting member 31 can be arranged on the same circumference, so that the end of the second magnet 33 away from the limiting member 31 is prevented from protruding towards the direction away from the limiting member 31 relative to the first magnet 32, which is beneficial to the space occupied by the first magnet 32 and the second magnet 33 along the axial direction, thereby contributing to improving the compactness of the direct current motor 100.

In some embodiments, the difference between the lengths of the first magnet 32 and the second magnet 33 is consistent with the recess depth of the limiting groove 312, so that the end of the first magnet 32 away from the limiting member 31 and the end of the second magnet 33 away from the limiting member 31 can be arranged on the same circumference.

In some embodiments, the length of the second magnet 33 is not less than 80% of the length of the first magnet 32, thereby avoiding an excessive difference in length between the second magnet 33 and the first magnet 32, allowing the magnitude of the magnetic force between the second magnet 33 and the first magnet 32 to approach.

In some embodiments, as shown in fig. 7, the length of the first magnet 32 is consistent with the length of the second magnet 33, and the width of the first magnet 32 is consistent with the width of the second magnet 33, so that the first magnet 32 and the second magnet 33 can adopt magnetic components with the same size specification, which is beneficial to avoiding errors of the first magnet 32 and the second magnet 33 in the installation process, and simultaneously, the preparation of the first magnet 32 or the second magnet 33 is convenient. Further, the thicknesses of the first magnet 32 and the second magnet 33 along the radial direction are the same, so that the inner surfaces of the first magnet 32 and the second magnet 33 are tangential to the same circumference, which contributes to improving the structural compactness of the direct current motor 100.

In some embodiments, as shown in connection with fig. 5-7, the rotor assembly 30 further includes a housing 34. The limiting member 31, the first magnet 32 and the second magnet 33 are accommodated in the housing 34. Specifically, the position of the stopper 31 in the housing 34 is fixedly set, so that the positions of the first magnet 32 and the second magnet 33 in the housing 34 in the circumferential direction can be defined. In some embodiments, the housing 34 is connected to the shaft 40. More specifically, the shaft 40 is connected to a central location of the housing 34.

In some embodiments, as shown in connection with fig. 5, the outer peripheral surface of the stopper 31 is disposed against the inner peripheral surface of the housing 34. Specifically, the limiting member 31 is embedded in the housing 34, and an interference fit is formed between the limiting member 31 and the housing 34, so that the relative angle between the limiting member 31 and the housing 34 is kept fixed. When the first magnet 32 or the second magnet 33 receives the magnetic force of the stator assembly 20, the first magnet 32 can transmit a certain rotational driving force to the housing 34 through the limiting slot 312, so as to drive the housing 34 to rotate relative to the stator assembly 20. In other embodiments, the stop 31 is integrally provided with the housing 34. Specifically, the relative angle between the stopper 31 and the housing 34 is thereby kept fixed.

In some embodiments, as shown in connection with fig. 6, the stop 31 is annular. Specifically, the limiting member 31 is provided with a through slot 311, and the through slot 311 of the limiting member 31 is used for passing through the shaft 40 or the stator assembly 20. In some embodiments, the limiting member 31 is clamped to the housing 34, and the relative angle between the limiting member and the housing 34 is kept fixed.

In some embodiments, as shown in fig. 5, the first magnet 32 and the second magnet 33 are attached to the inner peripheral surface of the case 34. Specifically, the first magnet 32 and the second magnet 33 are bonded to the inner peripheral surface of the housing 34 by an adhesive material, respectively, so that the first magnet 32 and the second magnet 33 are ensured to be stably arranged in the circumferential direction.

In some embodiments, as shown in connection with fig. 5, the housing 34 is in a semi-open configuration. The bottom surface of the limiting groove 312 faces the opening side of the housing 34. Specifically, the opening direction of the limiting groove 312 is the same as the opening direction of the housing 34, so that one end of the first magnet 32 can be conveniently aligned with the limiting groove 312 in the process of placing the first magnet 32 into the limiting groove 312.

In some embodiments, as shown in connection with fig. 2 and 5, the rotor assembly 30 further includes a bottom cover 38, the bottom cover 38 for interfacing with the open end of the housing 34. The bottom cover 38 cooperates with the housing 34 to form a space capable of accommodating the magnetic conductive member 21. Specifically, the bottom cover 38 is fixedly coupled to the open end of the housing 34. Specifically, a bearing member 41 is provided between the bottom cover 38 and the stator base 50 in the radial direction.

In some embodiments, as shown in connection with fig. 8, the rotor assembly 30 includes a housing 34, a first magnet 32, and a second magnet 33. The inner peripheral side of the housing 34 is provided with a first radial groove 341. A plurality of first radial grooves 341 are spaced apart along the inner circumference of the housing 34. The inner peripheral side of the housing 34 is also provided with a second radial groove 342. The housing 34 is provided with a second radial groove 342 between two adjacent first radial grooves 341, and the two first radial grooves 341 communicate via the second radial groove 342. The length of the first radial groove 341 in the axial direction of the housing 34 is longer than the length of the second radial groove 342 in the axial direction of the housing 34. The first magnet 32 is accommodated in the first radial groove 341, and the length of the first magnet 32 is greater than the length of the second radial groove 342. The second magnet 33 is accommodated in the second radial groove 342, and the length of the second magnet 33 is not greater than the length of the second radial groove 342.

Specifically, a plurality of first radial grooves 341 and a plurality of second radial grooves 342 are commonly distributed along the inner peripheral side of the housing 34, and a second radial groove 342 is disposed between two adjacent first radial grooves 341. The first radial groove 341 correspondingly accommodates the first magnet 32, and the second radial groove 342 correspondingly accommodates the second magnet 33. Since the length of the first radial groove 341 in the axial direction of the housing 34 is greater than the length of the second radial groove 342, the length of the first magnet 32 is greater than the length of the second radial groove 342, so that the first magnet 32 cannot move to the adjacent second radial groove 342 in the inner circumferential direction, and thus the position of the first magnet 32 in the inner circumferential direction of the housing 34 is defined. The second magnets 33 in the second radial grooves 342 are located between two adjacent first magnets 32, and thus the circumferential movement of the second magnets 33 is limited by the first magnets 32. Under the condition that the first magnet 32 and the second magnet 33 are limited, all the first magnet 32 and the second magnet 33 are prevented from being completely and closely connected due to magnetic force, the maximum distance between the first magnet 32 and the adjacent second magnet 33 is the sum of two negative value tolerances, the occurrence of negative value accumulation tolerance with overlarge absolute value is avoided, and a splicing gap with larger distance between the first magnet 32 and the second magnet 33 is prevented. In addition, since the adjacent two first radial grooves 341 are communicated with each other through the second radial groove 342, when there is a positive tolerance in the width of the second magnet 33 and a negative tolerance in the width of the adjacent at least one first magnet 32, the second magnet 33 can be placed between the two first magnets 32 through the remaining space of the first magnet 32, reducing the overall gap, and making the polar arc coefficient close to 1. Since the manufacturing tolerance opposite between the adjacent first magnet 32 and second magnet 33 is utilized, the first magnet 32 or second magnet 33 is not caused to collapse due to an excessive pressing force.

In some embodiments, the thicknesses of the first magnet 32 and the second magnet 33 are the same, and the radial depths of the first radial groove 341 and the second radial groove 342 along the housing 34 are the same, so that the inner surface of the first magnet 32 and the inner surface of the second magnet 33 are tangential to the same circumference, so that a uniform gap is maintained between the rotor assembly 30 and the stator assembly 20 along the circumferential direction, which is beneficial to improving the compactness of the dc motor 100.

In some embodiments, as shown in connection with fig. 9, the rotor assembly 30 includes: a positioning member 37, a first magnet 32 and a second magnet 33. The inner peripheral side of the positioning member 37 is provided with a third radial groove 371. A plurality of third radial grooves 371 are spaced apart along the inner circumference of the retainer 37. A plurality of first magnets 32 are distributed along the inner circumference of the positioning member 37. The first magnet 32 is accommodated in the third radial groove 371, and the radial thickness of the first magnet 32 is greater than the radial depth of the third radial groove 371. A plurality of second magnets 33 are distributed along the inner circumference of the positioning member 37. The second magnets 33 are disposed between adjacent first magnets 32 along the inner circumference of the positioning member 37.

Specifically, since the plurality of third radial grooves 371 are spaced apart along the inner circumference of the positioning member 37, the first magnets 32 are accommodated in the third radial grooves 371, and after the first magnets 32 are radially accommodated in the third radial grooves 371, the respective first magnets 32 are in stable relative positions therebetween. Since the radial thickness of the first magnet 32 is larger than the radial depth of the third radial groove 371, the first magnet 32 protrudes outward from the third radial groove 371 in the direction toward the axial center. In the case where the second magnets 33 are disposed between the adjacent first magnets 32 along the inner circumferential direction of the positioning piece 37, the circumferential movement of the second magnets 33 is limited by the first magnets 32. Under the condition that the first magnet 32 and the second magnet 33 are subjected to the circumferential limiting effect, the situation that all the first magnet 32 and the second magnet 33 are completely and closely connected due to magnetic force is avoided, the maximum distance between the first magnet 32 and the adjacent second magnet 33 is the sum of two negative value tolerances, the occurrence of negative value accumulation tolerance with overlarge absolute value is avoided, and a splicing gap with larger distance between the first magnet 32 and the second magnet 33 is prevented. In addition, since the adjacent first magnets 32 and second magnets 33 are in the space communicating in the circumferential direction, when there is a positive tolerance in the width of the second magnet 33 and a negative tolerance in the width of at least one adjacent first magnet 32, the second magnet 33 can be interposed between the two first magnets 32 with the remaining space of the first magnet 32, reducing the overall gap, and making the polar arc coefficient close to 1. Since the manufacturing tolerance opposite between the adjacent first magnet 32 and second magnet 33 is utilized, the first magnet 32 or second magnet 33 is not caused to collapse due to an excessive pressing force.

In some embodiments, the radial thickness of the second magnet 33 corresponds to an excess of the radial thickness of the first magnet 32 relative to the radial depth of the third radial groove 371, such that the inner surface of the first magnet 32 and the inner surface of the second magnet 33 are tangential to the same circumference, and a uniform gap is maintained between the rotor assembly 30 and the stator assembly 20 in the circumferential direction, which is beneficial for improving the compactness of the dc motor 100.

In some embodiments, the positioning member 37 is the housing 34 or an integral part of the housing 34. In other embodiments, the positioning member 37 is a bracket that is received within the housing 34.

The technical features of the above-described embodiments may be arbitrarily combined, and all possible combinations of the technical features in the above-described embodiments are not described for brevity of description, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the description.

The above examples only represent a few embodiments of the present application, which are described in more detail and are not to be construed as limiting the scope of the claims. It should be noted that it would be apparent to those skilled in the art that various modifications and improvements could be made without departing from the spirit of the present application, which would be within the scope of the present application. Accordingly, the scope of protection of the present application is to be determined by the claims appended hereto.

Claims (10)

1. A rotor assembly, comprising:

the limiting piece is provided with a plurality of limiting grooves on one side; the limiting groove is concavely arranged along the direction from one side to the other side of the limiting piece; the limiting grooves are distributed along the circumferential direction; the adjacent limit grooves are arranged at intervals;

the first magnets are distributed along the circumferential direction; one end of the first magnet is accommodated in the limit groove; and

The second magnets are distributed along the circumferential direction, and the second magnets are arranged between two adjacent first magnets.

2. The rotor assembly of claim 1 wherein the second magnet is shorter than the length of the first magnet; the length difference between the second magnet and the first magnet corresponds to the concave depth of the limit groove.

3. The rotor assembly of claim 1 wherein the length of the first magnet is consistent with the length of the second magnet; the width of the first magnet is consistent with the width of the second magnet.

4. The rotor assembly of claim 1, further comprising a housing, the limiter being housed within the housing; the outer peripheral surface of the limiting piece is propped against the inner peripheral surface of the shell, or the limiting piece and the shell are integrally arranged.

5. The rotor assembly of claim 4 wherein the housing is in a semi-open configuration; the bottom surface of the limiting groove faces to the opening side of the shell.

6. A rotor assembly, comprising:

one surface of the end cover is provided with a limit groove; the limiting grooves are distributed at intervals along the circumferential direction;

the shell wall is communicated with the two ends and one end of the shell wall is connected with the end cover;

a first magnet housed within the housing wall; a plurality of first magnets are distributed along the circumferential direction; one end of the first magnet is inserted into the limit groove; and

A second magnet housed within the housing wall; the second magnets are distributed along the circumferential direction, and the second magnets are arranged between two adjacent first magnets.

7. A rotor assembly, comprising;

the shell is provided with a first radial groove on the inner peripheral side; the plurality of first radial grooves are distributed at intervals along the inner circumference of the shell; the inner peripheral side of the shell is also provided with a second radial groove; the second radial grooves are arranged between two adjacent first radial grooves, and the two first radial grooves are communicated through the second radial grooves; the length of the first radial groove along the axial direction of the shell is greater than the length of the second radial groove;

a first magnet accommodated in the first radial groove; the length of the first magnet is greater than the length of the second radial groove; and

A second magnet accommodated in the second radial groove; the length of the second magnet is not greater than the length of the second radial groove.

8. A rotor assembly, comprising:

the inner peripheral side of the positioning piece is provided with a third radial groove; the third radial grooves are distributed at intervals along the inner circumference of the positioning piece;

the first magnets are distributed along the inner circumference of the positioning piece; the first magnet is accommodated in the third radial groove; the radial thickness of the first magnet is greater than the radial depth of the third radial groove; and

The second magnets are distributed along the inner circumference of the positioning piece; the second magnets are arranged between the adjacent first magnets along the inner circumference of the positioning piece.

9. A direct current motor comprising a rotor assembly as claimed in any one of claims 1 to 8.

10. A robot comprising the dc motor of claim 9.