Electric push rod and robot

Abstract

The present disclosure provides an electric push rod, comprising: a motor and a reverse lead screw arranged in an axial direction; the reverse lead screw comprises a nut and a screw rod; the motor is in driving connection with the nut, and the motor drives the nut to rotate to drive the screw rod to reciprocate in the axial direction. The present disclosure also provides a robot. The electric push rod has a compact structure, a high load density and a long service life.

Description

Technical Field

[0001] This disclosure relates to the field of mechanical actuation, and in particular to an electric actuator and a robot. Background Technology

[0002] In humanoid robot design, to achieve independent actuation and precise motion control of multi-degree-of-freedom joints, high-power-density electromechanical actuation systems need to be integrated into each joint module. However, the space for joints such as the hands and fingers of humanoid robots is extremely limited. The design of joint modules faces a contradiction between stringent space constraints and high torque output requirements, posing a significant technical challenge to the design and manufacturing of humanoid robots. Utility Model Content

[0003] This disclosure provides an electric linear actuator and a robot using the electric linear actuator.

[0004] In a first aspect, embodiments of this disclosure provide an electric linear actuator, the electric linear actuator comprising: a motor and a reverse lead screw, the motor and the reverse lead screw being arranged axially; the reverse lead screw comprising a nut and a lead rod; the motor being driven to the nut, the motor driving the nut to rotate, thereby causing the lead rod to reciprocate axially.

[0005] In some embodiments, the electric actuator further includes at least one eccentric shaft, which is offset from the axis of the motor and the reverse lead screw; the motor is connected to the nut via the eccentric shaft.

[0006] In some embodiments, the electric actuator further includes a first housing, in which an internal gear ring is disposed in the inner hole of the first housing; the output shaft of the motor is provided with a sun gear portion, and at least one planetary gear meshes with the internal gear ring and the sun gear portion respectively; the eccentric shaft is coaxially disposed with the planetary gear, one end of which is connected to the planetary gear and the other end of which is connected to the nut; the planetary gear performs planetary motion along the internal gear ring under the drive of the sun gear portion, and drives the nut to rotate through the eccentric shaft.

[0007] In some embodiments, the output shaft of the motor is provided with a transmission tooth, the outer periphery of the nut is provided with an external gear ring, and the eccentric shaft is provided with a first tooth and a second tooth; the first tooth meshes with the transmission tooth, and the second tooth meshes with the external gear ring; the eccentric shaft is circumferentially fixed with the output shaft as the center.

[0008] In some embodiments, the plurality of eccentric shafts are evenly distributed circumferentially around the output shaft of the motor.

[0009] In some embodiments, the electric actuator includes two eccentric shafts, which are symmetrically distributed about the output shaft of the motor.

[0010] In some embodiments, the electric actuator further includes a first housing, in which the inverted lead screw and the eccentric shaft are disposed; the electric actuator further includes a bearing, the outer ring of which is fixed in the first housing, and the inner ring of which is sleeved on the outer periphery of the nut.

[0011] In some embodiments, the electric actuator further includes a second housing, in which the motor is disposed; the first housing is spliced ​​with the second housing, and the outer wall of the first housing is flush with that of the second housing.

[0012] In some embodiments, the motor is a coreless motor.

[0013] Secondly, embodiments of this disclosure provide a robot, which includes the electric push rod described in the first aspect of this disclosure.

[0014] In this embodiment, the motor and the reverse lead screw are arranged coaxially. The motor drives the nut of the reverse lead screw to rotate, thereby driving the lead screw of the reverse lead screw to reciprocate along the axis. This achieves a compact structure for the electric push rod, which helps to reduce the size of the electric push rod. It can be applied to joints such as robot fingers to meet the requirements of high load density. It also helps to achieve independent and flexible control of the joint through separate programming. Attached Figure Description

[0015] Figure 1 This is a side sectional view of the electric actuator according to an embodiment of the present disclosure.

[0016] Figure 2 This is a perspective view of an electric actuator according to an embodiment of the present disclosure.

[0017] Figure 3 This is a partial side sectional view of the electric actuator according to an embodiment of the present disclosure.

[0018] Figure label:

[0019] 1. Electric actuator; 10. Reverse lead screw; 20. Eccentric shaft; 30. Motor; 40. Planetary gear; 11. Nut; 12. Lead screw; 2. First housing; 3. Second housing; 111. Internal thread; 121. External thread; 102. Flange; 104. Main body; 13. Base plate; 14. Center hole; 15. Rod; 16. Screw; 106. Bearing; 107. Inner ring; 108. Rolling element; 109. Outer ring; 21. 1. Step section; 22. Second step section; 31. Output shaft; 32. First end; 33. Second end; 34. Sun gear section; 35. First bearing; 36. Second bearing; 37. Fastener; 38. Motor housing; 39. Cover; 4. Front cover; 41. Outer perimeter; 42. Middle section; 43. Central through hole; 5. Rear cover; 51. Outer side; 52. Central section; 53. Rear space; 60. Connecting wire; 70. Fastener. Detailed Implementation

[0020] To enable those skilled in the art to better understand the technical solutions of this disclosure, the technical solutions of this disclosure will be described in detail below with reference to the accompanying drawings.

[0021] Exemplary embodiments will be described more fully below with reference to the accompanying drawings; however, these exemplary embodiments may be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will enable those skilled in the art to fully understand the scope of this disclosure.

[0022] Where there is no conflict, the various embodiments of this disclosure and the features thereof in the embodiments may be combined with each other.

[0023] As used herein, the term “and / or” includes any and all combinations of one or more related enumerated entries.

[0024] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit this disclosure. As used herein, the singular forms “a” and “the” are also intended to include the plural forms unless the context clearly indicates otherwise. It will also be understood that when the terms “comprising” and / or “made of” are used in this specification, the presence of the stated feature, integral, step, operation, element, and / or component is specified, but the presence or addition of one or more other features, integrals, steps, operations, elements, components, and / or groups thereof is not excluded.

[0025] In this article, the directional terms “front” and “rear” are used for ease of description, but these terms are not intended to limit the installation method of devices, components, etc.

[0026] The embodiments described herein can be described with reference to plan views and / or cross-sectional views using the ideal schematic diagrams of this disclosure. Therefore, the example illustrations can be modified according to manufacturing techniques and / or tolerances. Therefore, the embodiments are not limited to those shown in the drawings, but include modifications to configurations formed based on manufacturing processes. Therefore, the areas illustrated in the drawings are schematic in nature, and the shapes of the areas shown in the figures illustrate specific shapes of areas of an element, but are not intended to be limiting.

[0027] Unless otherwise specified, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art. It will also be understood that terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant art and this disclosure, and will not be interpreted as having an idealized or overly formal meaning, unless expressly so defined herein.

[0028] Because the space inside a robot's hand, and even its fingers, is very small, the movement of the fingers is usually driven by pulleys or links. However, the movement of the fingers lacks independence and flexibility, and it is difficult to control the fingers independently through separate programming.

[0029] The present disclosure aims to provide an electric actuator that can be integrated into the joints of a robot, such as fingers, and can be independently controlled through separate programming, thereby improving the independence and flexibility of the movements of the finger joints.

[0030] Figures 1 to 3 This is a schematic diagram of an electric actuator 1 provided in an embodiment of this disclosure. Wherein, Figure 1 This is a side sectional view of the electric actuator 1. Figure 2 This is a three-dimensional schematic diagram of electric actuator 1. Figure 3 This is a partial side sectional view of the electric linear actuator 1. In the embodiments of this disclosure, "front" refers to the output side of the electric linear actuator 1, and "rear" refers to the side of the electric linear actuator 1 opposite to the output side.

[0031] like Figure 1 As shown, the electric actuator 1 includes a reverse lead screw 10 and a motor 30. The reverse lead screw 10 includes a nut 11 and a lead screw 12. The motor 30 is connected to the nut 11 in a transmission manner, and the motor 30 can drive the nut 11 to rotate. The nut 11 is threadedly engaged with the lead screw 12, thereby driving the lead screw 12 to reciprocate along the axial direction. For example, as... Figure 1 As shown, the nut 11 includes an internal thread 111, and the lead screw 12 includes an external thread 121. The internal thread 111 of the nut 11 meshes with the external thread 121 of the lead screw 12, so that when the nut 11 is driven to rotate, the rotational motion of the nut 11 is converted into the linear motion of the lead screw 12 along the axis X inside the nut 11 through the threaded connection.

[0032] like Figure 1As shown, the reverse lead screw 10 and the motor 30 are coaxially arranged along the axis X. The lead screw 12 extends outward from the front side of the electric push rod 1 and can reciprocate along the axis X. The motor 30 is located on the rear side of the reverse lead screw 10.

[0033] In this embodiment, the motor 30 and the reverse lead screw 10 are arranged coaxially. The motor 30 drives the nut 11 of the reverse lead screw 10 to rotate, thereby driving the lead screw 12 of the reverse lead screw 10 to reciprocate along the axis. This makes the structure of the electric push rod compact, which is beneficial to reducing the volume of the electric push rod and also to increasing the load density.

[0034] In some embodiments, the electric linear actuator is the size of a human finger joint. For example, the electric linear actuator is 1 to 4 centimeters long and 1 to 2 centimeters in diameter. In some embodiments, the electric linear actuator has a load density greater than 200 kN / kg. For example, the electric linear actuator has a load density of 235 kN / kg.

[0035] When the electric actuator provided in this embodiment is integrated into the finger of a humanoid robot, it is advantageous to independently control each finger or even each joint through separate programming, thereby improving the independence and flexibility of the fingers and joints; it can also meet the demand for greater output force of the fingers and joints.

[0036] like Figure 1 As shown, the electric actuator 1 also includes at least one eccentric shaft 20, which is offset from the axis X of the motor 30 and the reverse lead screw 10; the motor 30 is connected to the nut 11 through the eccentric shaft 20 and drives the lead screw 12 to reciprocate along the axis X.

[0037] In this embodiment of the disclosure, the motor 30 and the reverse lead screw 10 are connected by the eccentric shaft 20 to drive the reverse lead screw 10. This reduces the axial space required for the connection and power transmission between the motor 30 and the reverse lead screw 10, shortens the axial length of the electric actuator 1, and makes the structure of the electric actuator 1 more compact and smaller in size. For example, the volume of the electric actuator 1 can be equivalent to that of a human finger.

[0038] In some embodiments, such as Figure 1 As shown, the lead screw 12 also includes a base plate 13 and a central hole 14. A screw 16 is fixed to the base plate 13 and passes through the base plate 13 and the central hole 14 to connect to one end of a rod 15 disposed within the nut 11. Those skilled in the art will understand that the specific connection method between the lead screw 12 and the rod 15 is not limited to... Figure 1The structure shown is as follows. For example, the specific positions and structures of the base plate 13, screw 16, and corresponding center hole 14 can be other ways, as long as the lead screw 12 and the rod 15 can be connected. The other end of the rod 15 can be connected to other components as needed, such as other components associated with the robot finger, without specific limitations. Thus, the linear movement of the lead screw 12 along the axis X within the nut 11 will drive the rod 15 to move linearly accordingly, thereby enabling the robot finger to perform certain actions as needed.

[0039] This disclosure does not specify the particular method by which the motor 30 is connected to the nut 11 via the eccentric shaft 20. For example, the output shaft 31 of the motor 30 is connected to the eccentric shaft 20 via friction drive, linkage drive, gear drive, etc., and the eccentric shaft 20 is connected to the nut 11 via friction drive, linkage drive, gear drive, etc., thereby connecting the motor 30 and the nut 11.

[0040] In some embodiments, such as Figure 1 , Figure 3 As shown, the electric actuator also includes a first housing 2, an internal gear ring is provided in the inner hole of the first housing 2, a sun gear 34 is provided on the output shaft 31 of the motor 30, and at least one planetary gear 40 meshes with the internal gear ring and the sun gear 34 respectively; an eccentric shaft 20 is coaxially arranged with the planetary gear 40, one end is connected to the planetary gear 40, and the other end is connected to the nut 11; the planetary gear 40 performs planetary motion along the internal gear ring under the drive of the sun gear 34, and drives the nut 11 to rotate through the eccentric shaft 20.

[0041] In this embodiment, the internal gear ring, the sun gear 34, the planetary gear 40, and the eccentric shaft 20 constitute a planetary reducer structure, which can improve the transmission efficiency from the motor 30 to the reverse lead screw 10, increase the load density of the electric push rod 1, facilitate the realization of a compact structure of the electric push rod 1, and extend the service life of the electric push rod 1.

[0042] In this embodiment, the internal gear ring can be directly disposed on the inner wall of the first housing 2; alternatively, it can be a structure independent of the first housing 2, fixed in the inner hole of the first housing 2 by means of interference fit or other connection methods. This embodiment does not impose any special limitations on this.

[0043] like Figure 3As shown, the inverted lead screw 10, eccentric shaft 20, and planetary reducer are arranged in the first housing 2. The inner bore of the first housing 2 has two adjacent inwardly protruding stepped portions, namely the first stepped portion 21 and the second stepped portion 22. The first stepped portion 21 protrudes further inward than the second stepped portion 22, that is, the inner diameter of the first housing 2 at the first stepped portion 21 is smaller than the inner diameter at the second stepped portion 22. An internal gear ring is formed on the inner circumference of the first stepped portion 21, or the internal gear ring is mounted on the inner circumference of the first stepped portion 21.

[0044] like Figure 3 As shown, the nut 11 of the reverse lead screw 10 includes a body 104 and a flange 102 disposed at the rear end of the body 104 and extending radially outward from the body 104. In some embodiments, one end of the eccentric shaft 20 is fixedly connected to the flange 102. In embodiments of this disclosure, the eccentric shaft 20 may be integrally formed with the planetary gear 40, and the eccentric shaft 20 may be the central shaft of the planetary gear 40; the eccentric shaft 20 may also be independent of the planetary gear 40, with the eccentric shaft 20 inserted into the central hole of the planetary gear 40 and fixedly connected to the planetary gear 40. This disclosure does not impose any special limitations on these embodiments.

[0045] like Figure 3 As shown, a bearing 106 is provided between the first housing 2 and the reverse lead screw 10. The bearing 106 is disposed between the outer peripheral surface of the main body 104 of the reverse lead screw 10 and the inner peripheral surface of the first housing 2, and is disposed between the first housing 2 and the nut 11 of the reverse lead screw 10 in any suitable manner. The bearing 106 includes an inner ring 107, an outer ring 109, and rolling elements 108 disposed between the inner ring 107 and the outer ring 109. The inner ring 107 is engaged with the outer peripheral surface of the reverse lead screw 10, and the outer ring 109 is fixed in the first housing 2 so that the reverse lead screw 10 can drive the inner ring 107 to rotate relative to the outer ring 109, and thus relative to the first housing 2, about the axis X.

[0046] In some embodiments, the rear end of the bearing 106 abuts against the front side of the second step portion 22, and the front end of the bearing 106 abuts against the rear side of the front end cover 4 (specifically the peripheral portion 41).

[0047] like Figure 3 As shown, the front cover 4 includes a peripheral portion 41, a central portion 42, and a central through-hole 43. The central portion 42 protrudes forward along axis X relative to the peripheral portion 41 to accommodate the body 104 of the reverse lead screw 10. The front surface of the body 104 of the reverse lead screw 10 abuts against the rear side of the central portion 42 of the front cover 4. The rod 15 extends outward through the central through-hole 43 for connection to other parts.

[0048] The embodiments disclosed herein do not impose any special limitation on the number of eccentric shafts 20, i.e. the number of planetary gears 40.

[0049] In some embodiments, the electric actuator 1 is provided with a plurality of planetary gears 40, which are evenly distributed circumferentially around the sun gear portion 34 of the output shaft 31. For example, the number of planetary gears 40 is 2, 3, 4, etc.

[0050] In some embodiments, the electric actuator 1 is provided with two planetary gears, which are symmetrically distributed around the sun gear portion 34 of the output shaft 31.

[0051] In this embodiment, multiple planetary gears 40 are evenly distributed circumferentially around the sun tooth portion 34 of the output shaft 31, which helps to improve the stability of power transmission from the motor 30 to the lead screw 10.

[0052] like Figure 1 The illustrated motor 30 includes an output shaft 31, a motor housing 38, and connecting wires 60, etc. The output shaft 31 is connected to the rear end of the motor housing 38 at its first end 32 via a first bearing 35 and extends forward. At its second end 33, it is connected to the front end of the motor housing 38 via a second bearing 36, and the second end 33 continues to extend forward to the outside. The connecting wires 60 pass through a through-hole in the rear end of the motor housing 38 and extend beyond the rear end of the motor housing 38 for connection to other components, such as a controller. In some embodiments, the connecting wires 60 may include or be connected to an encoder, etc.

[0053] Compared to pneumatic and hydraulic drive systems, using a small, high-power micro-motor is advantageous for integrating a mechanical system with significant output force into an extremely limited space. In this disclosure, the motor 30 can be a coreless motor, a brushless cogging motor, etc., and the specific type can be selected according to requirements. The coreless motor, in particular, features a coreless rotor design, reducing eddy current losses and exhibiting high efficiency, high power density, low inertia, and fast response.

[0054] In some embodiments, motor 30 is a DC brushless coreless motor. In this disclosure, by integrating a high-load-density DC brushless coreless motor with an eccentric shaft and a reverse lead screw design as described above, a more compact design can be achieved, which is beneficial for increasing the load density of the electric actuator 1. When applied to a robot's finger, it enables high finger dexterity and also provides the possibility of individual programming.

[0055] like Figure 1 , Figure 2 As shown, the electric actuator 1 includes a cylindrical first housing 2 and a second housing 3, as well as a circular front end cover 4 and a rear end cover 5. The first housing 2, the second housing 3, the front end cover 4, and the rear end cover 5 can be fixed together in any suitable manner to form a space that accommodates the reverse lead screw 10, the eccentric shaft 20, and the motor 30. Figure 2 The diagram schematically shows the first housing 2, the second housing 3, the front cover 4, and the rear cover 5 being secured to each other by multiple fasteners 70, but they can also be secured in other ways without specific limitations. Additionally, the diagram schematically shows multiple circular holes arranged around the periphery of the front cover 4; these holes can be configured in other numbers, shapes, and structures according to connection and arrangement requirements.

[0056] like Figure 1 As shown, the second housing 3 and the rear end cover 5 are fixed together to form an internal space that houses the motor 30. The front side of the second housing 3 is fixed to the motor housing 38 of the motor 30 by fasteners 37. The rear side of the rear end cover 5 is provided with a through hole for the connecting wire 60 to pass through. In some embodiments, the rear end cover 5 includes an outer portion 51 and a central portion 52. The central portion 52 protrudes rearward along the axis X relative to the outer portion 51, thereby forming a rear space 53 between the rear end cover 5 and the rear end of the motor 30 that can accommodate other required components. On the front side of the second housing 3, each fastener 37 is provided with a cover 39 to cover the fastener 37. The front side of the cover 39 is preferably flush with the front side of the second housing 3 to form a flat surface.

[0057] like Figure 1 , Figure 3 As shown, when assembled, the platform surface formed by the second housing 3 and the cover 39 abuts against the rear side of the first step portion 21, and the rear surface of the reverse lead screw 10 abuts against the front side of the first step portion 21.

[0058] In some embodiments, such as Figure 3 As shown, the rear end of the bearing 106 abuts against the front side of the second step portion 22, and the front end of the bearing 106 abuts against the rear side of the front end cover 4 (specifically the outer peripheral portion 41).

[0059] The front end cover 4 includes a peripheral portion 41, a central portion 42, and a central through-hole 43. The central portion 42 protrudes forward along axis X relative to the peripheral portion 41 to accommodate the body 104 of the reverse lead screw 10. The front surface of the body 104 of the reverse lead screw 10 abuts against the rear side of the central portion 42 of the front end cover 4. The rod 15 extends outward through the central through-hole 43 for connection to other parts.

[0060] In some embodiments, such as Figure 2 As shown, the first housing 2 and the second housing 3 of the electric push rod 1 are spliced ​​together, and the outer walls of the first housing 2 and the second housing 3 are flush, forming a cylindrical appearance.

[0061] This disclosure also provides an electric linear actuator, including a reverse lead screw and a motor. The reverse lead screw includes a nut and a lead rod. The motor is driven to rotate the nut, and the nut engages with the lead rod threadedly, thereby driving the lead rod 12 to reciprocate axially. The electric linear actuator also includes at least one eccentric shaft, which is offset from the axes of the motor and the reverse lead screw. The motor is driven to rotate through the eccentric shaft and the nut.

[0062] and Figures 1 to 3 The difference between the electric linear actuators shown is that the motor output shaft is equipped with a transmission gear, the outer circumference of the reverse lead screw nut is equipped with an external gear ring, and the eccentric shaft is equipped with a first gear and a second gear; the first gear meshes with the transmission gear, and the second gear meshes with the external gear ring; the eccentric shaft is fixed circumferentially with the output shaft as the center.

[0063] When the motor rotates, the output shaft drives the eccentric shaft to rotate through the meshing transmission teeth and the first tooth. Since the eccentric shaft is fixed circumferentially around the output shaft, the rotation of the eccentric shaft will drive the nut to rotate through the meshing second tooth and the outer gear ring, thereby causing the lead screw to reciprocate along the axial direction.

[0064] In this embodiment, the diameters of the first and second teeth of the eccentric shaft can be the same or different. In practical applications, the appropriate diameter can be selected based on requirements such as torque and rotational speed. This embodiment does not impose any special limitations on this.

[0065] The embodiments disclosed herein do not impose any special limitation on the number of eccentric shafts.

[0066] In some embodiments, the electric actuator is provided with multiple eccentric shafts, which are evenly distributed circumferentially around the transmission teeth of the motor's output shaft. For example, the number of eccentric shafts may be 2, 3, 4, etc.

[0067] In some embodiments, the electric actuator is provided with two eccentric shafts, which are symmetrically distributed around the transmission teeth of the output shaft.

[0068] In this embodiment of the present disclosure, multiple output shafts are evenly distributed circumferentially around the transmission teeth of the output shaft, which is beneficial to improving the stability of power transmission from the motor to the reverse lead screw.

[0069] This disclosure also provides a robot, including the electric actuator provided in this disclosure. In some embodiments, the robot is a humanoid robot, which includes a robotic arm, and the electric actuator provided in this disclosure is integrated into the internal space of the robotic arm.

[0070] Example embodiments have been disclosed herein, and while specific terminology has been used, it is for illustrative purposes only and should be construed as such, and is not intended to be limiting. In some instances, it will be apparent to those skilled in the art that features, characteristics, and / or elements described in connection with particular embodiments may be used alone, or in combination with features, characteristics, and / or elements described in connection with other embodiments, unless otherwise expressly indicated. Therefore, those skilled in the art will understand that various changes in form and detail may be made without departing from the scope of this disclosure as set forth by the appended claims.

Claims

1. An electric linear actuator, characterized in that, The electric actuator (1) includes: A motor (30) and a reverse lead screw (10) are arranged axially; The reverse lead screw (10) includes a nut (11) and a lead screw (12); The motor (30) is connected to the nut (11) for transmission. The motor (30) drives the nut (11) to rotate, which in turn drives the lead screw (12) to reciprocate along the axial direction.

2. The electric linear actuator according to claim 1, characterized in that, The electric push rod (1) also includes at least one eccentric shaft (20), which is offset from the axis of the motor (30) and the reverse lead screw (10); the motor (30) is connected to the nut (11) through the eccentric shaft (20).

3. The electric linear actuator according to claim 2, characterized in that, The electric push rod (1) also includes a first housing (2), in which an internal gear ring is provided in the inner hole of the first housing (2); the output shaft (31) of the motor (30) is provided with a sun gear (34), and at least one planetary gear meshes with the internal gear ring and the sun gear (34) respectively; the eccentric shaft (20) is coaxially arranged with the planetary gear, one end is connected to the planetary gear, and the other end is connected to the nut (11); the planetary gear moves along the internal gear ring under the drive of the sun gear (34), and drives the nut (11) to rotate through the eccentric shaft (20).

4. The electric actuator according to claim 2, characterized in that, The output shaft (31) of the motor (30) is provided with a transmission tooth, the outer periphery of the nut (11) is provided with an external gear ring, and the eccentric shaft (20) is provided with a first tooth and a second tooth; the first tooth meshes with the transmission tooth, and the second tooth meshes with the external gear ring; the eccentric shaft (20) is fixed circumferentially with the output shaft (31) as the center.

5. The electric actuator according to any one of claims 2 to 4, characterized in that, The plurality of eccentric shafts (20) are evenly distributed circumferentially around the output shaft (31) of the motor (30).

6. The electric linear actuator according to claim 5, characterized in that, The electric push rod (1) includes two eccentric shafts (20), which are symmetrically distributed about the output shaft (31) of the motor (30).

7. The electric actuator according to any one of claims 2 to 4, characterized in that, The electric push rod (1) also includes a first housing (2), and the reverse lead screw (10) and the eccentric shaft (20) are disposed in the first housing (2); The electric push rod (1) also includes a bearing (106), the outer ring (109) of the bearing (106) is fixed in the first housing (2), and the inner ring (107) of the bearing (106) is sleeved on the outer periphery of the nut (11).

8. The electric linear actuator according to claim 7, characterized in that, The electric push rod (1) also includes a second housing (3), and the motor (30) is disposed in the second housing (3); the first housing (2) is spliced ​​with the second housing (3), and the outer wall of the first housing (2) is flush with the outer wall of the second housing (3).

9. The electric linear actuator according to any one of claims 1 to 4, characterized in that, The motor (30) is a coreless motor.

10. A robot, characterized in that, The robot includes an electric actuator (1) according to any one of claims 1 to 9.

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