Multi-shaft robotic arm

Abstract

The utility model provides a multi-axis robotic arm which comprises a base, a first rotating part and a second rotating part, the first rotating part and the second rotating part are sequentially and rotationally connected, the first rotating part comprises a first arm section and a second arm section which are rotationally connected, the first arm section can rotate relative to the base, and the axial direction of a rotating shaft of the first arm section is in the first direction; the second rotating part comprises a third arm section, a fourth arm section and a fifth arm section which are rotationally connected in sequence from head to tail, the fifth arm section is used for mounting a load, the third arm section is rotationally connected with the second arm section, the axial direction of a rotating shaft of the third arm section is in the second direction, and the first direction is not parallel to the second direction; the height of the first rotating part is larger than that of the second rotating part, the first arm section and the third arm section are connected to the same side of the second arm section, rotating space is formed among the first arm section, the second arm section and the third arm section, and the fourth arm section and the fifth arm section can rotate to be located in the rotating space and rotate in the rotating space. The multi-shaft robotic arm provided by the utility model is more flexible to rotate.

Description

Technical Field

[0001] The utility model relates to the technical field of industrial robots, and particularly relates to a multi-axis robotic arm. Background Art

[0002] A multi-axis robot, also known as a single-axis manipulator, an industrial robotic arm, an electric cylinder, etc., is an operating machine that can achieve automatic control, is reprogrammable, has multiple degrees of freedom, and the degrees of freedom of movement form a spatial right-angle relationship, and has multiple uses. Multi-axis robots can be applied to common industrial production fields such as dispensing, dipping, spraying, palletizing, sorting, packaging, welding, metal processing, handling, loading and unloading, assembly, printing, etc., and have significant application value in replacing manual labor, improving production efficiency, and stabilizing product quality.

[0003] The existing multi-axis robotic arms have a relatively large occupied space, are restricted when working in narrow spaces, and the swinging between each arm segment is likely to affect each other, resulting in poor flexibility of the overall multi-axis robotic arm. Content of the Utility Model

[0004] In view of this, the purpose of the utility model is to provide a more flexible multi-axis robotic arm.

[0005] The technical solution adopted by the utility model is as follows:

[0006] Provide a multi-axis robotic arm, including a base and a first rotating part and a second rotating part that are installed on the base and are sequentially rotatably connected. The first rotating part includes a first arm segment and a second arm segment that are rotatably connected. The first arm segment is rotatable relative to the base, and the axis of the rotating shaft of the first arm segment is along a first direction. The second rotating part includes a third arm segment, a fourth arm segment, and a fifth arm segment that are sequentially rotatably connected from the head to the tail. The fifth arm segment is used for installing a load. The third arm segment is rotatably connected to the second arm segment, and the axis of the rotating shaft of the third arm segment is along a second direction. The first direction and the second direction are not parallel. The height of the first rotating part is greater than the height of the second rotating part. The first arm segment and the third arm segment are respectively connected to the same side of the second arm segment. There is a rotating space between the first arm segment, the second arm segment, and the third arm segment. The fourth arm segment and the fifth arm segment can rotate to be located in the rotating space and rotate within the rotating space.

[0007] Preferably, the angle range within which the second rotating part can rotate relative to the second arm segment is greater than or equal to 360 degrees.

[0008] In the first rotating part, the axes of the rotating shafts of adjacent arm segments are not parallel. In the second rotating part, the axes of the rotating shafts of adjacent arm segments are not parallel. The rotation angle ranges of the first arm segment, the third arm segment, and the fourth arm segment are greater than or equal to 360 degrees.

[0009] Preferably, the first direction is perpendicular to the second direction, the axial direction of the rotation axis of the second arm segment is perpendicular to the axial direction of the rotation axis of the first arm segment, the axial direction of the rotation axis of the third arm segment is perpendicular to the axial direction of the rotation axis of the fourth arm segment, the axial direction of the rotation axis of the fourth arm segment is perpendicular to the axial direction of the rotation axis of the fifth arm segment, and the axial direction of the rotation axis of the second arm segment is parallel to the axial direction of the rotation axis of the third arm segment.

[0010] Preferably, the tail end of the first arm segment is connected to the head end of the second arm segment, the head end of the third arm segment is connected to the tail end of the second arm segment, and the height of the second arm segment is greater than the height of the second rotating part.

[0011] Preferably, the fifth arm segment is provided with an externally output mounting rotating part, the axial direction of the rotating shaft of the mounting rotating part is not parallel to the axial direction of the rotating shaft of the fifth arm segment, and the load is mounted on the mounting rotating part; the first arm segment, the second arm segment, the third arm segment, the fourth arm segment, the fifth arm segment and the mounting rotating part can all rotate independently under the drive of the corresponding driving mechanism, and when the second arm segment rotates away from the base and extends upward in the first direction, the fifth arm segment can rotate to be located above the rotating shaft of the first arm segment, so that the rotating shaft of the mounting rotating part is coaxially arranged with the rotating shaft of the first arm segment.

[0012] Preferably, the mounting rotating portion can be rotated to be located between the fifth arm segment and the first arm segment;

[0013] and / or,

[0014] The mounting rotating part can be rotated to between the fourth arm segment and the first arm segment. When the second arm segment is rotated in the direction away from the base to extend upward in the first direction, the fifth arm segment can be rotated to be located above the rotation axis of the first arm segment, so that the rotation axis of the mounting rotating part is coaxially arranged with the rotation axis of the first arm segment and the rotation axis of the fourth arm segment.

[0015] Preferably, the fifth arm segment can be rotated to be located between the fourth arm segment and the second arm segment;

[0016] Alternatively, the fifth arm segment can be rotated to be located between the fourth arm segment and the first arm segment; the fourth arm segment can be rotated to have a portion thereof located between the fifth arm segment and the second arm segment and another portion thereof located between the fifth arm segment and the third arm segment.

[0017] Preferably, the third arm segment and / or the fifth arm segment include a transverse column and a longitudinal column which are interconnected and axially perpendicular, and independent joint assemblies are respectively arranged in the transverse column and the longitudinal column, and some wires and / or air pipes pass through one of the transverse column and the longitudinal column and the corresponding joint assembly, enter the other of the transverse column and the longitudinal column and the corresponding joint assembly, and pass out from the other of the transverse column and the longitudinal column.

[0018] Preferably, the fifth arm segment is also provided with an externally output mounting rotating portion, the load is mounted on the mounting rotating portion, the third arm segment and the fifth arm segment both include a transverse column and a longitudinal column which are interconnected and axially perpendicular, the transverse column of the third arm segment is connected to the second arm segment, and the longitudinal column is connected to the fourth arm segment; the longitudinal column of the fifth arm segment is connected to the mounting rotating portion, and the transverse column is connected to the fourth arm segment.

[0019] Preferably, the fifth arm segment is also provided with a mounting rotating part for external output, the load is installed on the mounting rotating part, the base and the first arm segment, the first arm segment and the second arm segment, the second arm segment and the third arm segment, the third arm segment and the fourth arm segment, and the fourth arm segment and the fifth arm segment are all rotatably connected through a joint assembly, and the fifth arm segment is also provided with a joint assembly connected to the mounting rotating part, and some wires and / or air pipes pass through the joint assemblies between the base and the first arm segment, between the first arm segment and the second arm segment, between the second arm segment and the third arm segment, between the third arm segment and the fourth arm segment, and between the fourth arm segment and the fifth arm segment in sequence, and pass through the mounting rotating part.

[0020] Preferably, the base and the first arm segment, the first arm segment and the second arm segment, the second arm segment and the third arm segment, the third arm segment and the fourth arm segment, and the fourth arm segment and the fifth arm segment are all rotatably connected via joint assemblies, and at least one of the joint assemblies has the following structure:

[0021] The joint assembly includes a main output shaft, a connecting shaft, a driving mechanism and a reduction mechanism. The main output shaft is an axially through hollow structure. The connecting shaft is sleeved on the outside of the main output shaft. The reduction mechanism is sleeved on the outside of the main output shaft. The connecting shaft is connected to the input end of the reduction mechanism. The output end of the reduction mechanism is connected to the main output shaft. The driving mechanism is sleeved on the outside of the connecting shaft and is used to drive the connecting shaft to rotate, and then drive the main output shaft to rotate after being decelerated by the reduction mechanism.

[0022] The main output shaft is the rotating shaft of the corresponding first arm segment, second arm segment, third arm segment, fourth arm segment and fifth arm segment, and the driving mechanism is the driving mechanism of the corresponding first arm segment, second arm segment, third arm segment, fourth arm segment and fifth arm segment.

[0023] Preferably, the joint assembly further comprises a brake mechanism, which cooperates with the connecting shaft and is used to stop the connecting shaft from rotating when braking, thereby stopping the main output shaft from rotating. The brake mechanism, the driving mechanism and the reduction mechanism are sequentially arranged along the axial direction of the main output shaft toward the output end of the main output shaft, and an end cover is arranged at one end of the main output shaft away from the reduction mechanism. The end cover is sleeved on the main output shaft, and a first bearing is arranged between the end cover and the main output shaft.

[0024] The speed reduction mechanism is a harmonic reducer, which includes a wave generator, a flexspline, and a rigid gear. The wave generator is sleeved outside the main output shaft and connected to the connecting shaft. The flexspline is sleeved outside the wave generator, and the rigid gear is sleeved outside the flexspline and connected to the main output shaft;

[0025] The joint assembly further includes a heat dissipation mechanism, which is sleeved outside the connecting shaft and can rotate with the connecting shaft. The heat dissipation mechanism, the braking mechanism, the driving mechanism, and the speed reduction mechanism are sequentially arranged along the axial direction of the main output shaft towards the output end of the main output shaft; The heat dissipation mechanism includes a heat dissipation mounting seat, which is sleeved outside the connecting shaft and can rotate with the connecting shaft. An annular connecting plate is arranged on the heat dissipation mounting seat, and a plurality of fan blades are arranged at intervals along the circumferential direction of the annular connecting plate.

[0026] Preferably, the load is a grasping device, a detection device, a fixing jig, or a connecting device.

[0027] Preferably, at least one of the following sealing structures of the robotic arm is adopted between the base and the first arm segment, between the first arm segment and the second arm segment, between the second arm segment and the third arm segment, between the third arm segment and the fourth arm segment, and between the fourth arm segment and the fifth arm segment:

[0028] The sealing structure of the robotic arm includes a front arm, a rear arm, and a joint assembly. Mounting holes are respectively formed on the first surface of the front arm and the second surface of the rear arm. One end of the joint assembly extends into the front arm through the mounting hole on the first surface of the front arm and is connected to the front arm, and the other end extends into the rear arm through the mounting hole on the second surface of the rear arm and is connected to the rear arm. The front arm and the rear arm can rotate relative to each other through the joint assembly. A sealing member is arranged at the joint assembly and between the front arm and the rear arm or between one of the front arm and the rear arm and the joint assembly;

[0029] A neck facing the rear arm is arranged at the mounting hole of the front arm. The neck on the front arm extends into the rear arm through the mounting hole of the rear arm, and the sealing member is arranged between the side wall of the neck on the front arm and the side wall of the rear arm; or

[0030] A connecting member is arranged on the outer side wall of the joint assembly. When connecting the joint assembly between the front arm and the rear arm, the joint assembly is mounted on the front arm or the rear arm through the connecting member thereon, and the sealing member is arranged between the joint assembly and the side wall of the front arm or the rear arm where the connecting member is not mounted.

[0031] In the multi-axis robotic arm according to the embodiments of the present utility model, the first arm segment and the third arm segment are respectively connected to the same side of the second arm segment, reducing the lateral occupied space of the overall robotic arm and forming a rotating space through which the fourth arm segment and the fifth arm segment can pass, enabling the robotic arm to achieve multi-angle and multi-posture adjustments within a relatively small space range. On the basis of saving occupied space, it can also have high adjustment flexibility. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The above and other objects, features, and advantages of the present utility model will become clearer through the preferred embodiments of the present utility model shown in the drawings. The same reference numerals in all the drawings indicate the same parts, and the drawings are not deliberately drawn to scale in actual size, with the emphasis on showing the gist of the present utility model.

[0033] Figure 1 and Figure 2 are schematic diagrams of the structures of different states of the multi-axis robotic arm according to Embodiment 1 of the present utility model.

[0034] Figure 3 is a cross-sectional view of the multi-axis robotic arm according to Embodiment 1 of the present invention.

[0035] Figure 4 is a schematic diagram of the structure of the first rotating part according to Embodiment 1;

[0036] Figure 5 and Figure 6 are schematic diagrams of the structures of different states of the multi-axis robotic arm according to Embodiment 2 of the present invention.

[0037] Figure 7 is a schematic diagram of the structure of the joint assembly according to the embodiment of the present invention.

[0038] Figure 8 is Figure 7 a cross-sectional view of the joint assembly.

[0039] Figure 9 is Figure 8 a schematic diagram of the structure of the heat dissipation mechanism of the joint assembly.

[0040] Figure 10 is a schematic diagram of the sealing structure of the multi-axis robotic arm according to the embodiment of the present invention.

[0041] Figure 11 is a schematic diagram of the sealing structure of the multi-axis robotic arm according to another embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0042] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand the present invention and be able to implement it. However, the embodiments cited do not limit the present invention. In this embodiment, it should be understood that the terms "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention, rather than indicating or implying 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 of the present invention.

[0043] It should be noted that when an element is considered to be "connected" to another element, it can be directly connected to the other element and integrated with it, or there may be an intermediate element at the same time. The terms "installation", "one end", "the other end" and similar expressions used in the present invention are only for the purpose of illustration.

[0044] Please refer to Figures 1 to 11 , the embodiment of the present invention provides a multi-axis robotic arm, including a base 80 and a first rotating part 101 and a second rotating part 102 that are installed on the base 80 and connected in sequence. The first rotating part 101 includes a first arm segment 10 and a second arm segment 20 that are rotatably connected. Further, the first arm segment 10 and the second arm segment 20 are connected end to end. The first arm segment 10 is rotatable relative to the base 80, and the axis of rotation of the first arm segment 10 is along the first direction. In this embodiment, the first arm segment 10 is directly rotatably connected to the base 80. In other embodiments, a rotating member that can rotate relative to the base 80 and the axis of rotation is along the first direction can be provided on the base 80. The first arm segment 10 is fixed on the rotating member or the first arm segment 10 is rotatably connected to the rotating member. Driven by the rotating member, the first arm segment 10 is rotatable relative to the base 80 and the axis of rotation is along the first direction. The second rotating part includes a third arm segment 30, a fourth arm segment 40, and a fifth arm segment 50 that are rotatably connected in sequence from the head to the tail. Further, the first arm segment 10, the second arm segment 20, the third arm segment 30, the fourth arm segment 40, and the fifth arm segment 50 are rotatably connected in sequence from the head to the tail. The third arm segment 30 is rotatably connected to the second arm segment 20, and the axis of rotation of the third arm segment 30 is along the second direction. The fifth arm segment is used to install a load 90 (such as a fixture, a detection device, a welding device, etc.). As Figure 1 an example, the height a of the first rotating part (the distance from the bottom end to the top end of the first rotating part) is greater than the height b of the second rotating part (the distance from the bottom end to the top end of the second rotating part), so that when the second rotating part rotates relative to the second arm segment driven by the third arm segment, it can be not interfered by the first rotating part, so that the third arm segment can drive the second rotating part 102 as a whole to achieve a rotation angle greater than or equal to 360 degrees. AsFigure 2 For example, in this embodiment, the first direction and the second direction are not parallel and are directions that can intersect each other.

[0045] In this embodiment, the first arm segment 10 and the third arm segment 30 are respectively connected to the same side of the second arm segment 20, so that the extension directions of the first arm segment 10 and the third arm segment 30 relative to the second arm segment 20 are the same. The installation of the first and third arm segments both occupies the same side of the second arm segment 20, reducing the lateral occupied space of the overall robotic arm. In this embodiment, there is a rotation space f between the first arm segment 10, the second arm segment 20, and the third arm segment 30. The fourth arm segment 40 and the fifth arm segment 50 can be rotated to be located in the rotation space f and can rotate within the rotation space f (refer to Figures 1 - 2 ). Also because the first and third arm segments are on the same side, a rotation space f can be formed. This rotation space can enable the third arm segment 30 to drive the fourth arm segment 40 and the fifth arm segment 50 to pass through this rotation space f when the third arm segment 30 rotates. In this way, the rotation angle of the third arm segment 30 relative to the second arm segment can be greater than or equal to 360 degrees, and the third arm segment 30 can drive the fourth arm segment 40 and the fifth arm segment 50 to swing to more positions. At the same time, the rotation space f formed by the installation of the first and third arm segments on the same side is used as the space through which the fourth and fifth arms can pass, enabling the robotic arm to achieve multi-angle and multi-posture adjustment within a relatively small space range. On the basis of saving occupied space, it can also have high adjustment flexibility, so that each arm segment of the multi-axis robotic arm will not interfere with the previous arm segment during operation, making the multi-axis robotic arm have a high degree of freedom and flexibility and can complete complex actions in a narrow space.

[0046] The multi-axis robotic arm provided by the present utility model is usually installed at a certain position and works with a load 90 (such as a fixture, a detection device, a welding device, etc.). The head end of the multi-axis robotic arm referred to here is its installation end, and the tail end is its working end. From the head to the tail refers to from the head end to the tail end. In this embodiment, the base 80 is used to be installed on the ground, on the wall, or on other working platforms, and the fifth arm segment 50 is used to install the load 90. In the first and second embodiments, an installation rotating part 53 that can rotate relative to the rotating shaft of the fifth arm segment 50 is provided on the fifth arm segment 50, and the load 90 is installed on the installation rotating part 53. In some other embodiments, the load 90 can also be directly fixed on the fifth arm segment 50.

[0047] Refer to Figure 2, in a preferred embodiment, the first direction and the second direction are two perpendicular directions. The perpendicularity referred to in this embodiment is substantially perpendicular, and there may be certain measurement errors, which are approximately within 90 ± 10 degrees. The angle range within which the second rotating part 102 can rotate relative to the second arm segment is greater than or equal to 360 degrees. When the third arm segment 30 rotates, it can drive the fourth arm segment 40 and the fifth arm segment 50 to rotate integrally through the rotating space. Of course, in addition to being driven by the third arm segment 30 to rotate, the fourth arm segment 40 and the fifth arm segment 50 themselves will also rotate. For example, the fourth arm segment 40 can rotate relative to the third arm segment 30, and the fifth arm segment 50 can rotate relative to the fourth arm segment 40. The angle range of rotation referred to in the present utility model means that it can have a relatively large rotation range, rather than being limited to rotating definitely greater than or equal to 360 degrees. It can achieve rotation at any angle within this rotation range, such as 30 degrees, 60 degrees, 180 degrees, 270 degrees, etc.

[0048] Reference Figure 2 and Figure 6 , in a preferred embodiment, in the first rotating part 101, the axial directions of the rotating shafts of adjacent arm segments (the first arm segment 10 and the second arm segment 20) are not parallel. In the second rotating part 102, the axial directions of the rotating shafts of adjacent arm segments are not parallel. By arranging the swing arms with different axial directions of the rotating shafts in each rotating part, more swing possibilities can be achieved, and the flexibility of the robotic arm can be improved.

[0049] Reference Figures 1 - 2 and Figures 5 - 6 In a preferred embodiment, the rotation angle ranges of the first arm segment 10, the third arm segment 20, the fourth arm segment 30, and the fifth arm segment 50 are greater than or equal to 360 degrees. The rotation angle range of the first arm 10 referred to in this embodiment means the rotation of the first arm segment 10 relative to the base 80, that is, the rotation angle range of the first arm segment 10 around the axial direction y1 of the rotating shaft is greater than or equal to 360 degrees. The rotation angle range of the third arm 30 means the rotation of the third arm segment 30 relative to the second arm segment 20, that is, the rotation angle range of the third arm 30 around the axial direction Y3 of the rotating shaft is greater than or equal to 360 degrees. The rotation angle range of the fourth arm segment 30 refers to the rotation of the fourth arm segment 40 relative to the third arm segment 30, that is, the rotation angle range of the fourth arm segment 40 around the axial direction y4 of the rotating shaft is greater than or equal to 360 degrees. In the example of Embodiment 1 (reference Figures 1 - 2 ), the rotation angle range of the fifth arm segment 50 can also be greater than or equal to 360 degrees. In the example of Embodiment 2 (reference Figures 5 - 6) When the length of the second arm segment is extended to a certain height, the rotation angle range of the fifth arm segment 50 can also be greater than or equal to 360 degrees. The rotation angle range of the fifth arm segment 50 refers to the rotation range of the fifth arm segment 50 around the rotation axis y5. The rotation axis range defined in the present invention means that the arm segment can rotate to any angle within this range, for example, it can rotate to 30 degrees, 60 degrees, 90 degrees, etc., and will not list them one by one here. In this embodiment, the rotation angle ranges of multiple arm segments are relatively large, and in addition to independent rotation, each arm segment will also be driven by the rotation of other arm segments to achieve more posture adjustments.

[0050] Reference Figures 1 - 2 and Figures 5 - 6 , in a further preferred embodiment, the axial direction y2 of the rotation axis of the second arm segment 20 is perpendicular to the axial direction y1 of the rotation axis of the first arm segment 10, the axial direction y3 of the rotation axis of the third arm segment 30 is perpendicular to the axial direction y4 of the rotation axis of the fourth arm segment 40, and the axial direction y4 of the rotation axis of the fourth arm segment 40 is perpendicular to the axial direction y5 of the rotation axis of the fifth arm segment 50. The perpendicularity referred to in the present invention is basically perpendicular, and there may be a certain measurement error, which is basically about 90 ± 10 degrees. Through this layout in this embodiment, the axial directions of the rotation axes of multiple arm segments are perpendicular to each other, which can achieve more adjustment possibilities and enable the robotic arm to have a more flexible posture adjustment.

[0051] Reference Figures 1 - 2 and Figures 5 - 6 , in a preferred embodiment, the axial direction y2 of the rotation axis of the second arm segment 20 is parallel to the axial direction y3 of the rotation axis of the third arm segment 30. The parallelism referred to here is basically parallel, allowing a certain error of ±10 degrees.

[0052] Reference Figures 1 - 2 and Figures 5 - 6 , in a preferred embodiment, the tail end of the first arm segment 10 is connected to the head end of the second arm segment 20, and the head end of the third arm segment 30 is connected to the tail end of the second arm segment 20, so that there can be a relatively large rotation space f between the first arm segment 10 and the third arm segment 30. At the same time, the height c of the second arm segment is greater than the height of the second rotating part b, which enables the second rotating part 102 to rotate through the rotation space f formed between the first arm segment 10 and the third arm segment 30 in a specific posture.

[0053] Reference Figures 1 - 6, in a preferred embodiment, an externally output mounting rotating part 53 is provided on the fifth arm segment 50. The axial direction y6 of the rotating shaft of the mounting rotating part 53 is not parallel to the axial direction y5 of the rotating shaft of the fifth arm segment 50. Further, the axial direction y6 of the rotating shaft of the mounting rotating part 53 is substantially perpendicular to the axial direction y5 of the rotating shaft of the fifth arm segment 50, so that the rotating mounting part 53 can provide another direction of rotation relative to the fifth arm segment 50. The load 90 is mounted on the mounting rotating part 53. By providing the mounting rotating part 53, the load 90 can work more flexibly. In this embodiment, the first arm segment 10, the second arm segment 20, the third arm segment 30, the fourth arm segment 40, the fifth arm segment 50 and the mounting rotating part 53 can all rotate independently under the drive of corresponding drive mechanisms.

[0054] When the second arm segment 20 rotates away from the base in a direction and extends upward in the first direction (which can be understood by referring to Figure 2 and Figure 6 ), that is, when the end of the second arm segment 20 rotates to be substantially at the highest point, the fifth arm segment 50 can rotate to be located above the rotation axis of the first arm segment 10, so that the rotation axes of the mounting rotating part 53 and the first arm segment 10 are coaxially arranged at an upper and lower interval (which can be understood by referring to Figure 1 and Figure 5 ). These two axes are concentric, which can make the twisting range smaller when reaching certain postures.

[0055] Refer to Figure 1 , in the solution of Embodiment 1, the mounting rotating part 53 can rotate to be located between the fifth arm segment 50 and the first arm segment 10, with a simple and compact structure and better flexibility. Refer to Figure 5 , in the solution of Embodiment 2, the mounting rotating part 53 can rotate to be located between the fourth arm segment 40 and the fifth arm segment 50. When the second arm segment 20 rotates away from the base in a direction and extends upward in the first direction (which can be understood by referring to Figure 6 ), that is, when the end of the second arm segment 20 rotates to be substantially at the highest point, the fifth arm segment 50 can rotate to be located above the rotation axis of the first arm segment, so that the rotation axes of the mounting rotating part 53, the first arm segment 10 and the fourth arm segment 40 are coaxially arranged at an upper and lower interval. In this embodiment, more rotation axes can swing to be coaxial, which can further make the twisting range smaller when reaching certain postures. The coaxiality referred to in the present utility model does not mean sharing a rotating shaft, but means that the rotation axes are substantially coincident.

[0056] Refer to Figures 1 - 2 , in the solution of Embodiment 1, the fifth arm segment 50 can rotate to be located between the fourth arm segment 40 and the second arm segment 20, that is, the fifth arm segment 50 can rotate within the rotation space surrounded by the first arm segment 10, the second arm segment 20, the third arm segment 30 and the fourth arm segment 40, making the robotic arm structure simple and compact, having a large rotation space and good flexibility.

[0057] refer to Figures 5 - 6 In the solution of the second embodiment, the fifth arm segment 50 can be rotated to be located between the fourth arm segment 40 and the first arm segment 10; the fourth arm segment 40 can be rotated to a point where a portion 402 of the fourth arm segment 40 is located between the fifth arm segment 50 and the second arm segment 20, and another portion 401 is located between the fifth arm segment 50 and the third arm segment 30. That is, the fourth arm segment 40 has a turning point, so that the fifth arm segment 50 can not only rotate in the rotation space, but also realize the coaxial arrangement of the rotating shaft of the installation rotating part, the rotating shaft of the first arm segment 10, and the rotating shaft of the fourth arm segment.

[0058] It should be noted that the rotation axes of the first arm segment 10, the second arm segment 20, the third arm segment 30, the fourth arm segment 40, and the fifth arm segment 50 referred to in this application all refer to the rotation axes of the arm segments relative to the previous arm segment (towards the head end of the multi-axis robot arm), and the rotation angle range referred to also refers to the rotation angle range relative to the previous arm segment, wherein for the first arm segment 10, it is the rotation angle range relative to the base 80. The axial direction of the rotation axis of the first arm segment 10 along the first direction is not strictly limited to be parallel to the first direction, and there may also be a certain angle deviation (for example, a deviation of 2-10 degrees). Similarly, in the above descriptions of "along the second direction", "along the third direction" and the following descriptions of "vertical", there may be a certain angle deviation.

[0059] refer to Figures 1 - 6 In a preferred embodiment, the third arm segment and / or the fifth arm segment include a transverse column and a longitudinal column that are interconnected and axially perpendicular, and independent joint assemblies 70 are respectively provided in the transverse column and the longitudinal column, and part of the wires and / or the air pipe 60 pass through one of the transverse column and the longitudinal column and the corresponding joint assembly, enter the other of the transverse column and the longitudinal column and the corresponding joint assembly, and pass out from the other of the transverse column and the longitudinal column. The wires are used to transmit electricity to the electrical components (such as the joint assembly 70) in each arm segment, and the air pipe is used to provide conveying gas for the gas load carried by the multi-axis robot arm. In some embodiments, the air pipe may not be provided. Through the combination of the transverse column and the longitudinal column, the structure of the multi-axis robot arm is made more compact, and the wires and / or the air pipe 60 are also inside the arm segment, so it is very suitable for working in a narrow space.

[0060] refer to Figure 1 and Figure 4, in a preferred embodiment, both the third arm segment 30 and the fifth arm segment 50 include a transverse cylinder and a longitudinal cylinder that are connected to each other and perpendicular to each other axially. The transverse cylinder 32 of the third arm segment 30 is connected to the second arm segment 20, and the longitudinal cylinder 31 is connected to the fourth arm segment 40; the longitudinal cylinder 51 of the fifth arm segment 50 is connected to the mounting rotating part 53, and the transverse cylinder 52 is connected to the fourth arm segment 40. In this embodiment, through the arrangement of the transverse cylinder and the longitudinal cylinder, the arm segment can be turned, the length of the one-way extension of the arm segment can be reduced, and at the same time, a compact structure and a rotation angle exceeding 360 degrees can be achieved.

[0061] Reference Figure 3 , in a preferred embodiment, the base 80 and the first arm segment 10, the first arm segment 10 and the second arm segment 20, the second arm segment 20 and the third arm segment 30, the third arm segment 30 and the fourth arm segment 40, and the fourth arm segment 40 and the fifth arm segment 50 are all rotatably connected through the joint assembly 70. A joint assembly 70 connected to the mounting rotating part 53 is also provided in the fifth arm segment 50. Part of the wires and / or air pipes 60 sequentially pass through the joint assemblies between the base 80 and the first arm segment 10, between the first arm segment 10 and the second arm segment 20, between the second arm segment 20 and the third arm segment 30, between the third arm segment 30 and the fourth arm segment 40, and between the fourth arm segment 40 and the fifth arm segment 50, and exit from the mounting rotating part 53. The part of the wires and / or air pipes 60 is referred to because part of the wires and air pipes 60 (such as the wires connecting the first arm segment 20) may not need to extend to the fifth arm segment 50. By this wiring method, the structure of the multi-axis robotic arm can be made more concise and safer.

[0062] Reference Figure 3 and Figures 7 - 9 , in a preferred embodiment, the base 80 and the first arm segment 10, the first arm segment 10 and the second arm segment 20, the second arm segment 20 and the third arm segment 30, the third arm segment 30 and the fourth arm segment 40, and the fourth arm segment 40 and the fifth arm segment 50 are all rotatably connected through the joint assembly 70, and at least one of the joint assemblies 70 has the following structure.

[0063] The joint assembly 70 includes a main output shaft 701, a connecting shaft 702, a driving mechanism 704, and a speed reduction mechanism 703. The main output shaft 701 has a hollow structure that runs through axially, allowing wires and air pipes 900 to pass through. A flange is provided at the output end of the main output shaft 701 for connecting to the corresponding arm section body. The connecting shaft 702 is sleeved outside the main output shaft 701, and the speed reduction mechanism 703 is sleeved outside the main output shaft 701. The connecting shaft 702 is connected to the input end of the speed reduction mechanism 703, and the output end of the speed reduction mechanism 703 is connected to the main output shaft 702. The driving mechanism 704 is sleeved outside the connecting shaft 702 and is used to drive the connecting shaft 702 to rotate, and then drive the main output shaft 701 to rotate after being decelerated by the speed reduction mechanism 703. Specifically, the driving mechanism 704 includes a stator 7042 and a rotor 7041. The rotor 7041 is sleeved outside the connecting shaft 702, and the stator 7042 is sleeved outside the rotor 7041 for driving the rotor 7041 to rotate. The housings of the speed reduction mechanism 703 and the driving mechanism 704 can be fixed to the previous arm section, and the output end of the main output shaft 701 is fixedly connected to the subsequent arm section. Since the driving mechanism 704 generally rotates at a relatively high speed while the swing arm rotates at a relatively low speed, the power output of the driving mechanism 704 is transmitted to the connecting shaft 702, transferred to the input end of the speed reduction mechanism 703 through the connecting shaft 702, decelerated by the speed reduction mechanism 703, and then output from the output end of the speed reduction mechanism 703 to the main output shaft 701, and then transmitted to the arm section body through the main output shaft 701. The main output shaft 701 is provided with a hollow structure that runs through axially, which allows cables, air pipes and other lines to pass through the inner cavity of the main output shaft 701 to achieve electrical connection, etc., avoiding the external placement of cables, air pipes, etc. of the robotic arm, thereby making the internal structure of the robotic arm compact and the appearance neat and beautiful.

[0064] It can be understood that when the above joint assembly 70 is used between the base 80 and the first arm segment 10, between the first arm segment 10 and the second arm segment 20, between the second arm segment 20 and the third arm segment 30, between the third arm segment 30 and the fourth arm segment 40, and between the fourth arm segment 40 and the fifth arm segment 50, the main output shaft 701 is the rotating shaft of the corresponding first arm segment 10, second arm segment 20, third arm segment 30, fourth arm segment 40, and fifth arm segment 50, and the driving mechanism 704 is the driving mechanism of the corresponding first arm segment 10, second arm segment 20, third arm segment 30, fourth arm segment 40, and fifth arm segment 50.

[0065] Reference Figure 8 , in a preferred embodiment, the joint assembly 70 further includes a braking mechanism 705. The braking mechanism 705 cooperates with the connecting shaft 702 to stop the connecting shaft 702 from rotating during braking, and thus stop the main output shaft 701 from rotating. The braking mechanism 705, the driving mechanism 704, and the speed reduction mechanism 703 are sequentially arranged along the axial direction of the main output shaft 701 towards the output end of the main output shaft 703 to Figure 8From the perspective of [description not provided], they are arranged in sequence from bottom to top. This arrangement makes the structure of the joint assembly 70 very compact and small in size. At one end of the main output shaft 701 facing away from the reduction mechanism 703 (i.e., the end opposite to the output end), an end cover 707 is provided. The end cover 707 is sleeved outside the main output shaft 701, and a first bearing 708 is provided between the end cover 707 and the main output shaft 701. This first bearing 708 can enhance the load-bearing capacity of the joint assembly 70 and is more durable.

[0066] Reference Figure 8 , in the preferred embodiment, the reduction mechanism 703 is a harmonic reducer. The reduction mechanism 703 includes a wave generator 7031, a flexspline 7033, and a rigid gear 7032. The wave generator 7031 serves as the input end of the reduction mechanism 703 and is sleeved outside the connecting shaft 702 and the main output shaft 701. The flexspline 7033 is sleeved outside the wave generator 7031, and the rigid gear 7032 is sleeved outside the flexspline 7033 and is connected to the main output shaft 701.

[0067] Reference Figures 8 - 9 , in the preferred embodiment, the joint assembly 70 further includes a heat dissipation mechanism 706. The heat dissipation mechanism 706 is sleeved outside the connecting shaft 702 and can rotate with the connecting shaft 702 for dissipating heat from the joint assembly 70. The heat dissipation mechanism 706, the braking mechanism 705, the driving mechanism 704, and the reduction mechanism 703 are arranged in sequence along the axial direction of the main output shaft 701 towards the output end of the main output shaft 703. The heat dissipation mechanism 706 includes a heat dissipation mounting seat 7061. The heat dissipation mounting seat 7061 is sleeved outside the connecting shaft 702 and can rotate with the connecting shaft 706. An annular connecting plate 7064 is provided on the heat dissipation mounting seat 7061. A plurality of fan blades 7062 are arranged at intervals along the circumferential direction of the annular connecting plate 7064. By providing the heat dissipation assembly 706, the wind generated by the rotation of the fan blades 7062 can quickly blow out the heat generated inside the joint assembly 70. A plurality of heat dissipation holes can be provided on the end cover 707, and the hot air flow fanned by the fan blades 7062 will quickly flow out from the heat dissipation holes to the outside of the joint assembly 70, thus ensuring the normal operation of the joint assembly 70.

[0068] Please refer to Figure 10 and Figure 11 , in the preferred embodiment, at least one of the following machine arm sealing structures is adopted between the base 80 and the first arm segment 10, between the first arm segment 10 and the second arm segment 20, between the second arm segment 20 and the third arm segment 30, between the third arm segment 30 and the fourth arm segment 40, and between the fourth arm segment 40 and the fifth arm segment 50.

[0069] The sealing structure of the robotic arm includes a forearm 200, a rear arm 100, and a joint assembly 70. Mounting holes (mounting hole 201 on the forearm 200 and mounting hole 101 on the rear arm 100) are respectively provided on the first surface of the forearm 200 and the second surface of the rear arm 100. One end of the joint assembly 70 extends into the forearm 200 through the mounting hole 201 on the first surface of the forearm 200 and is connected to the forearm 200, and the other end extends into the rear arm 100 through the mounting hole 101 on the second surface of the rear arm 100 and is connected to the rear arm 100. The structure of the joint assembly 70 can refer to the description of the aforementioned joint assembly 70. Specifically, the housing of the drive mechanism 704 of the joint assembly 70 can be fixed on the forearm 200, and the main output shaft 701 of the joint assembly 70 can be connected to the rear arm 100. The forearm 200 and the rear arm 100 can rotate relative to each other through the joint assembly 70. When the above-mentioned sealing structure of the robotic arm is provided between the base 80 and the first arm segment 10, the base 80 can be the forearm 200, and the first arm segment 10 can be the rear arm 100, and so on, which can be applied to the sealing structures between the first arm segment 10 and the second arm segment 20, between the second arm segment 20 and the third arm segment 30, between the third arm segment 30 and the fourth arm segment 40, and between the fourth arm segment 40 and the fifth arm segment 50. A seal 300 is provided at the joint assembly 70 and between the forearm 200 and the rear arm 100 or between one of the forearm 200 and the rear arm 100 and the joint assembly 70. The seal 300 can be an O-ring.

[0070] By providing the seal 300 at the joint assembly 70 and between the forearm 200 and the rear arm 100 or between one of the forearm 200 and the rear arm 100 and the joint assembly 70, the sealing structure of the robotic arm can effectively prevent external moisture, dust and other debris from entering the interior of the robotic arm from the moving connection of adjacent arm segments, so as to improve the sealing performance inside the robotic arm, protect the precision components inside the robotic arm, ensure the normal operation of the robotic arm, and extend its service life.

[0071] Please refer to Figure 10 In a preferred embodiment, a neck 202 facing the rear arm 100 is provided at the mounting hole 201 of the forearm 200. The neck 202 on the forearm 200 extends into the rear arm 100 through the mounting hole 101 of the rear arm 100, and a seal 300 is provided between the outer wall of the neck 202 of the forearm 200 and the inner wall of the rear arm 100.

[0072] Please refer to Figure 11, in another embodiment, a connecting member 71 is provided on the outer sidewall of the joint assembly 70. When connecting the joint assembly 70 between the forearm 200 and the rear arm 100, the joint assembly 70 is mounted on the forearm 200 or the rear arm 100 through the connecting member 71 thereon, and a seal 300 is provided between the joint assembly 70 and the sidewall of the forearm 200 or the rear arm 100 on which the connecting member 71 is not mounted. Specifically, in Figure 10 , the connecting member 71 is connected to the top end of the forearm 200, and the top end of the forearm 200 is inserted into the mounting hole 101 of the rear arm 100, and a seal 300 is provided between the joint assembly 70 and the inner sidewall of the rear arm 100. In other embodiments, the connecting member 71 may also be connected to the inner sidewall of the rear arm 100, and at this time, a seal 300 is provided between the joint assembly 70 and the forearm 200.

[0073] In this specification, unless otherwise clearly defined and limited, the first feature being "on" or "under" the second feature may be that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "over" and "on top of" the second feature may be that the first feature is directly above or obliquely above the second feature, or merely indicates that the first feature has a higher horizontal height than the second feature. The first feature being "under", "below" and "beneath" the second feature may be that the first feature is directly below or obliquely below the second feature, or merely indicates that the first feature has a lower horizontal height than the second feature.

[0074] In the description of this specification, the description with reference to terms such as "preferred embodiment", "another embodiment", "other embodiments" or "specific examples" etc. means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0075] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present application. Those of ordinary skill in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present application.

Claims

1. A multi-axis robotic arm, characterized in that, It includes a base, a first rotating part and a second rotating part which are mounted on the base and are sequentially rotatably connected. The first rotating part includes a first arm segment and a second arm segment which are rotatably connected. The first arm segment is rotatable relative to the base, and the axial direction of the rotating shaft of the first arm segment is along a first direction. The second rotating part includes a third arm segment, a fourth arm segment and a fifth arm segment which are sequentially rotatably connected from the head to the tail. The fifth arm segment is used for mounting a load. The third arm segment is rotatably connected to the second arm segment, and the axial direction of the rotating shaft of the third arm segment is along a second direction. The first direction and the second direction are not parallel. The height of the first rotating part is greater than the height of the second rotating part. The first arm segment and the third arm segment are respectively connected to the same side of the second arm segment. There is a rotating space between the first arm segment, the second arm segment and the third arm segment. The fourth arm segment and the fifth arm segment can be rotated to be located in the rotating space and rotate within the rotating space.

2. The multi-axis robotic arm according to claim 1, wherein The angle range within which the second rotating part can rotate relative to the second arm segment is greater than or equal to 360 degrees. In the first rotating part, the axial directions of the rotating shafts of adjacent arm segments are not parallel. In the second rotating part, the axial directions of the rotating shafts of adjacent arm segments are not parallel. The rotation angle ranges of the first arm segment, the third arm segment and the fourth arm segment are greater than or equal to 360 degrees.

3. The multi-axis robotic arm according to claim 2, wherein, The first direction and the second direction are perpendicular. The axial direction of the rotating shaft of the second arm segment is perpendicular to the axial direction of the rotating shaft of the first arm segment. The axial direction of the rotating shaft of the third arm segment is perpendicular to the axial direction of the rotating shaft of the fourth arm segment. The axial direction of the rotating shaft of the fourth arm segment is perpendicular to the axial direction of the rotating shaft of the fifth arm segment. The axial direction of the rotating shaft of the second arm segment is parallel to the axial direction of the rotating shaft of the third arm segment.

4. The multi-axis robotic arm according to claim 1, wherein, The tail end of the first arm segment is connected to the head end of the second arm segment. The head end of the third arm segment is connected to the tail end of the second arm segment. The height of the second arm segment is greater than the height of the second rotating part.

5. The multi-axis robotic arm according to claim 1, wherein An externally output mounting rotating part is provided on the fifth arm segment. The axial direction of the rotating shaft of the mounting rotating part is not parallel to the axial direction of the rotating shaft of the fifth arm segment. The load is mounted on the mounting rotating part. The first arm segment, the second arm segment, the third arm segment, the fourth arm segment, the fifth arm segment and the mounting rotating part can all rotate independently under the drive of corresponding drive mechanisms. When the second arm segment rotates away from the base and extends upward in the first direction, the fifth arm segment can be rotated to be located above the rotating shaft of the first arm segment, so that the rotating shaft of the mounting rotating part is coaxially arranged with the rotating shaft of the first arm segment.

6. The multi-axis robotic arm according to claim 5, characterized in that The mounting rotating part can be rotated to be located between the fifth arm segment and the first arm segment. and / or The mounting rotating part can be rotated to be located between the fourth arm segment and the fifth arm segment. When the second arm segment rotates away from the base and extends upward in the first direction, the fifth arm segment can be rotated to be located above the rotating shaft of the first arm segment, so that the rotating shaft of the mounting rotating part is coaxially arranged with the rotating shaft of the first arm segment and the rotating shaft of the fourth arm segment.

7. The multi-axis robotic arm according to claim 1, wherein The fifth arm segment can be rotated to be located between the fourth arm segment and the second arm segment. Alternatively, the fifth arm segment can be rotated to be located between the fourth arm segment and the first arm segment; the fourth arm segment can be rotated to have a portion thereof located between the fifth arm segment and the second arm segment and another portion thereof located between the fifth arm segment and the third arm segment.

8. The multi-axis robotic arm according to claim 1, wherein, The third arm segment and / or the fifth arm segment include a transverse column and a longitudinal column that are interconnected and axially perpendicular, and independent joint components are respectively arranged in the transverse column and the longitudinal column. Some wires and / or air pipes pass through one of the transverse column and the longitudinal column and the corresponding joint component, enter the other of the transverse column and the longitudinal column and the corresponding joint component, and pass out from the other of the transverse column and the longitudinal column.

9. The multi-axis robotic arm according to claim 8, wherein, The fifth arm segment is also provided with an externally output mounting rotating portion, and the load is mounted on the mounting rotating portion. The third arm segment and the fifth arm segment both include a transverse column and a longitudinal column which are interconnected and axially perpendicular. The transverse column of the third arm segment is connected to the second arm segment, and the longitudinal column is connected to the fourth arm segment; the longitudinal column of the fifth arm segment is connected to the mounting rotating portion, and the transverse column is connected to the fourth arm segment.

10. The multi-axis robotic arm according to any one of claims 1-9, characterized in that, The fifth arm segment is also provided with an installation rotating part for external output, and the load is installed on the installation rotating part. The base and the first arm segment, the first arm segment and the second arm segment, the second arm segment and the third arm segment, the third arm segment and the fourth arm segment, and the fourth arm segment and the fifth arm segment are all rotationally connected through joint components. The fifth arm segment is also provided with a joint component connected to the installation rotating part, and some wires and / or air pipes pass through the joint components between the base and the first arm segment, between the first arm segment and the second arm segment, between the second arm segment and the third arm segment, between the third arm segment and the fourth arm segment, and between the fourth arm segment and the fifth arm segment in sequence, and pass through the installation rotating part.

11. The multi-axis robotic arm according to any one of claims 1-9, characterized in that, The base and the first arm segment, the first arm segment and the second arm segment, the second arm segment and the third arm segment, the third arm segment and the fourth arm segment, and the fourth arm segment and the fifth arm segment are all rotatably connected via joint components, and at least one of the joint components has the following structure: The joint assembly includes a main output shaft, a connecting shaft, a driving mechanism and a reduction mechanism. The main output shaft is an axially through hollow structure. The connecting shaft is sleeved on the outside of the main output shaft. The reduction mechanism is sleeved on the outside of the main output shaft. The connecting shaft is connected to the input end of the reduction mechanism. The output end of the reduction mechanism is connected to the main output shaft. The driving mechanism is sleeved on the outside of the connecting shaft and is used to drive the connecting shaft to rotate, and then drive the main output shaft to rotate after being decelerated by the reduction mechanism. The main output shaft is the rotating shaft of the corresponding first arm segment, second arm segment, third arm segment, fourth arm segment and fifth arm segment, and the driving mechanism is the driving mechanism of the corresponding first arm segment, second arm segment, third arm segment, fourth arm segment and fifth arm segment.

12. The multi-axis robotic arm according to claim 11, wherein The joint assembly further includes a brake mechanism, which cooperates with the connecting shaft and is used to stop the connecting shaft from rotating when braking, thereby stopping the main output shaft from rotating. The brake mechanism, the driving mechanism and the reduction mechanism are sequentially arranged along the axial direction of the main output shaft toward the output end of the main output shaft. An end cover is arranged at one end of the main output shaft away from the reduction mechanism. The end cover is sleeved on the main output shaft, and a first bearing is arranged between the end cover and the main output shaft. The speed reduction mechanism is a harmonic speed reducer, and the speed reduction mechanism includes a wave generator, a flexible wheel and a rigid wheel. The wave generator is sleeved on the outside of the main output shaft and connected to the connecting shaft, the flexible wheel is sleeved on the outside of the wave generator, and the rigid wheel is sleeved on the outside of the flexible wheel and connected to the main output shaft. The joint assembly also includes a heat dissipation mechanism, which is sleeved on the outside of the connecting shaft and can rotate with the connecting shaft. The heat dissipation mechanism, brake mechanism, drive mechanism and reduction mechanism are arranged in sequence along the axial direction of the main output shaft toward the output end of the main output shaft; the heat dissipation mechanism includes a heat dissipation mounting seat, which is sleeved on the outside of the connecting shaft and can rotate with the connecting shaft. An annular connecting plate is arranged on the heat dissipation mounting seat, and a plurality of fan blades are arranged at intervals along its circumference.

13. The multi-axis robotic arm according to any one of claims 1-9, characterized in that, The load is a grasping device, a detecting device, a fixing fixture or a connecting device.

14. The multi-axis robotic arm according to any one of claims 1-9, characterized in that, At least one of the sealing structure of the following robot arm is used between the base and the first arm segment, between the first arm segment and the second arm segment, between the second arm segment and the third arm segment, between the third arm segment and the fourth arm segment, and between the fourth arm segment and the fifth arm segment: The sealing structure of the robot arm comprises a forearm, a rear arm and a joint assembly, wherein the first surface of the forearm and the second surface of the rear arm are respectively provided with mounting holes, one end of the joint assembly extends from the mounting hole on the first surface of the forearm into the forearm and is connected to the forearm, and the other end extends from the mounting hole on the second surface of the rear arm into the rear arm and is connected to the rear arm, the forearm and the rear arm can rotate relative to each other through the joint assembly, and a sealing member is provided at the joint assembly and between the forearm and the rear arm or between one of the forearm and the rear arm and the joint assembly; A neck portion facing the rear arm is provided at the mounting hole of the forearm, the neck portion on the forearm extends into the rear arm through the mounting hole of the rear arm, and the sealing member is provided between the side wall of the neck portion of the forearm and the side wall of the rear arm; or A connecting piece is provided on the outer side wall of the joint assembly. When the joint assembly is connected between the forearm and the rear arm, the joint assembly is installed on the forearm or the rear arm through the connecting piece thereon, and the sealing piece is provided between the joint assembly and the side wall of the forearm or the rear arm where the connecting piece is not installed.

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