A robot joint module with sealing structure

Abstract

The utility model relates to the field of robot technology, and in particular to a robot joint module with a sealing structure, which includes a motor assembly, a friction brake assembly, a harmonic reducer, and a shaft group that runs through the motor assembly, the friction brake assembly, and the harmonic reducer from top to bottom, wherein the brake assembly includes a brake pad, a brake pad fixing, and a brake body, and the harmonic reducer includes a flexible wheel, a steel wheel, a reducer bearing, and a wave generator, and the shaft group includes a coaxially arranged input shaft and an output shaft, and a pressure difference sealing structure is arranged between the inner surface of the input shaft and the outer surface of the output shaft. The robot joint module with a sealing structure described in the utility model has a pressure difference sealing structure arranged between the inner surface of the input shaft and the outer surface of the output shaft, and no additional sealing member is required, so that there is not only no friction between the output shafts, which improves the transmission efficiency, but also has high reliability, almost no maintenance, and a long service life.

Description

Technical Field

[0001] The utility model relates to the technical field of robots, in particular to a robot joint module with a sealing structure. Background Art

[0002] With the rapid development of automation technology, robots, as an important automation equipment, are gaining more and more attention and are being used more and more widely. As an important branch of robots, medical robots are developing rapidly. More and more medical robots are being developed and put into the market after rigorous testing, becoming a powerful assistant for frontline medical staff and patients.

[0003] Due to the particularity of medical application scenarios, there are many stringent requirements for the safety and reliability of medical robots, and the core component that determines the motion performance of medical robots is the joint module. Therefore, the operating accuracy and reliability of the joint module of medical robots are required to be high. In the robot joint module of the related technology, the sealing between the coaxial input shaft and the output shaft has always been a difficult problem. If a sealing ring is used for sealing, not only will the transmission efficiency be reduced due to friction, but the sealing ring is easy to wear and has a short life, and it is easy to cause oil leakage after wear. Utility Model Content

[0004] In view of this, the utility model provides a robot joint module with a sealing structure, which at least partially solves the problems existing in the prior art.

[0005] A robot joint module with a sealing structure comprises a motor assembly, a brake assembly, a harmonic reducer and a shaft group passing through the motor assembly, the brake assembly and the harmonic reducer arranged from top to bottom, wherein:

[0006] The motor assembly includes a housing, a rotor, and a stator, wherein the housing is a cylindrical metal structure, and the stator is arranged on the inner wall of the housing;

[0007] The brake assembly comprises a brake pad, a brake pad fixing part, and a brake body, wherein the brake body and the brake pad fixing part are both flange-shaped structures, and the rotor is sleeved on the brake pad fixing part;

[0008] The harmonic reducer includes a flexible wheel, a steel wheel, a reducer bearing, and a wave generator.

[0009] The shaft group includes an input shaft and an output shaft coaxially arranged, wherein the output shaft is a hollow shaft, the input shaft is sleeved on the output shaft, a mounting flange is arranged at the lower end of the input shaft, the wave generator is assembled on the mounting flange and forms a harmonic reducer with the flexible wheel, the steel wheel, and the reducer bearing; a pressure difference sealing structure is arranged between the inner surface of the input shaft and the outer surface of the output shaft.

[0010] Preferably, the pressure differential sealing structure is that at least two countersunk holes are formed on the inner surface of the input shaft, and the inner diameter of the countersunk holes gradually decreases from bottom to top, and shaft shoulders corresponding to the countersunk holes are formed on the outer surface of the output shaft, and a sealing gap is formed between the shaft shoulders and the corresponding countersunk holes.

[0011] Preferably, the pressure differential sealing structure is that a conical barrel-shaped through hole is formed on the inner surface of the input shaft, and the inner diameter of the through hole gradually decreases from bottom to top, a frustum corresponding to the through hole is formed on the outer surface of the output shaft, and a sealing gap is formed between the through hole and the frustum.

[0012] Preferably, the size of the sealing gap remains consistent from bottom to top or gradually decreases from bottom to top.

[0013] Preferably, the pressure differential sealing structure is as follows: at least two countersunk holes are formed on the inner surface of the input shaft, and the inner diameter of the countersunk holes gradually decreases from bottom to top, a frustum is formed on the outer surface of the output shaft, and a sealing gap is formed between the countersunk holes and the frustum.

[0014] Preferably, the pressure differential sealing structure is as follows: at least two countersunk holes are formed on the inner surface of the input shaft, and the inner diameter of the countersunk holes gradually decreases from bottom to top; the output shaft is a straight shaft, and the countersunk holes and the outer surface of the output shaft form a sealing gap.

[0015] Preferably, a conical barrel-shaped through hole is formed on the inner surface of the input shaft, and the inner diameter of the through hole gradually decreases from bottom to top; the output shaft is a straight shaft, and a sealing gap is formed between the through hole and the outer surface of the output shaft.

[0016] Preferably, the lower end of the output shaft is a flange-shaped structure, and the upper end surface of the output shaft flange is fixedly connected to the steel wheel and the inner ring of the reducer bearing.

[0017] Preferably, the brake pad fixing part and the brake body are both sleeved on the middle part of the input shaft, wherein the brake pad fixing part is fixed on the input shaft, the outer edge of the brake body extends to the outer surface of the shell in the diameter direction and is fixedly connected to the shell, and the brake pad is connected to the lower end surface of the brake pad fixing part and constitutes a braking surface with the upper end surface of the brake body.

[0018] Preferably, sealing rings are provided between the flexible wheel and the brake body, and between the steel wheel and the flange-shaped structure of the output shaft.

[0019] The robot joint module with a sealing structure described in the utility model has a pressure difference sealing structure between the inner surface of the input shaft and the outer surface of the output shaft, and no additional sealing is required. Therefore, there is no friction between the output shafts, which improves the transmission efficiency, and the robot joint module has high reliability, almost no maintenance, and a long service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions of the embodiments of the utility model, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0021] Figure 1 This is a three-dimensional schematic diagram of a robot joint module with a sealing structure according to an embodiment of the utility model;

[0022] Figure 2 This is a cross-sectional schematic diagram of a robot joint module with a sealing structure according to an embodiment of the utility model;

[0023] Figure 3 This is an exploded view of the entire robot joint module with a sealing structure according to an embodiment of the utility model;

[0024] Figure 4 This is a schematic diagram of a brake assembly of a robot joint module with a sealing structure according to an embodiment of the utility model;

[0025] Figure 5 An exploded view of a harmonic reducer of a robot joint module with a sealing structure according to an embodiment of the utility model;

[0026] Figure 6 This is an exploded view of the shaft group of the robot joint module with a sealing structure according to an embodiment of the utility model;

[0027] Figure 7 Schematic diagram of the pressure difference sealing structure of the robot joint module with sealing structure according to the embodiment of the utility model Figure 1 ;

[0028] Figure 8 Schematic diagram of the pressure difference sealing structure of the robot joint module with sealing structure according to the embodiment of the utility model Figure 2 ;

[0029] Fig. 9 A cross-sectional view of another embodiment of the robot joint module according to an embodiment of the present invention Figure 1 ;

[0030] Fig.10A cross-sectional view of another embodiment of the robot joint module according to an embodiment of the present invention Figure 1 ;

[0031] Fig.11 A cross-sectional view of another embodiment of the robot joint module according to an embodiment of the present invention Figure 2 ;

[0032] Fig.12 A cross-sectional view of another embodiment of the robot joint module according to an embodiment of the present invention Figure 2 .

[0033] Description of reference numerals:

[0034] 1-motor assembly, 11-housing, 12-rotor, 13-stator;

[0035] 2-brake assembly, 21-brake pad fixing member, 22-brake pad, 23-brake body, 231-second bearing mounting position;

[0036] 3-harmonic reducer, 31-flexible wheel, 32-steel wheel, 33-reducer bearing, 34-wave generator;

[0037] 4-shaft assembly, 41-input shaft, 411-positioning shoulder, 412-first thread, 42-input locking nut, 43-first input bearing, 44-second input bearing, 45-output shaft, 451-second thread, 46-output locking nut, 47-first output bearing;

[0038] 5-sealing gap, 51-countersunk hole, 52-cone, 53-shaft shoulder. DETAILED DESCRIPTION

[0039] The embodiments of the utility model are described in detail below with reference to the accompanying drawings.

[0040] It should be noted that the following embodiments and features in the embodiments may be combined with each other in the absence of conflict; and, based on the embodiments in the present disclosure, all other embodiments obtained by ordinary technicians in the field without making any creative work are within the scope of protection of the present disclosure.

[0041] It should be noted that various aspects of the embodiments within the scope of the appended claims are described below. It should be apparent that the aspects described herein may be embodied in a wide variety of forms, and any specific structure and / or function described herein is merely illustrative. Based on the present disclosure, it should be understood by those skilled in the art that an aspect described herein may be implemented independently of any other aspect, and two or more of these aspects may be combined in various ways. For example, any number of aspects described herein may be used to implement the device and / or practice the method. In addition, other structures and / or functionalities other than one or more of the aspects described herein may be used to implement this device and / or practice this method.

[0042] Figures 1 to 10 The three-dimensional schematic diagram, cross-sectional schematic diagram, overall exploded diagram and exploded diagram of each component of the robot joint module with a sealing structure described in the embodiment of the utility model are now described in detail in conjunction with the accompanying drawings.

[0043] See also Figures 1 to 10 As shown, the robot joint module with a sealing structure described in this embodiment includes a motor assembly 1, a friction brake assembly 2, a harmonic reducer 3 and a shaft group 4 that runs through the motor assembly 1, the friction brake assembly 2 and the harmonic reducer 3, which are arranged from top to bottom, wherein: the motor assembly 1 includes a housing 11, a rotor 12, and a stator 13; the brake assembly 2 includes a brake pad 22, a brake pad fixing member 21, and a brake body 23; the harmonic reducer 3 includes a flexible wheel 31, a steel wheel 32, a reducer bearing 33, and a wave generator 34; the shaft group 4 includes a coaxially arranged input shaft 41 and an output shaft 45, and also includes an input locking nut 42, a first input bearing 43, a second input bearing 44, an output locking nut 46 and a first output bearing 47;

[0044] Among them, the stator 13 is provided with a winding coil, the rotor 12 is a permanent magnet, the output shaft 45 is a hollow shaft, the input shaft 41 is sleeved on the output shaft 45, the shell 11 is a cylindrical metal structure, and the stator 13 is arranged on the inner wall of the shell 11; the brake body 23 and the brake pad fixing part 21 are both flange-like structures, the stator 13 is sleeved on the brake pad fixing part 21, the brake pad fixing part 21 and the brake body 23 are both sleeved in the middle part of the input shaft 41, the brake pad fixing part 21 is fixed on the input shaft 41, the outer edge of the brake body 23 extends to the outer surface of the shell 11 along the diameter direction and is fixedly connected to the shell 11, the brake pad 22 is connected to the lower end surface of the brake pad fixing part 21 and constitutes a braking surface with the upper end surface of the brake body 23.

[0045] The above-mentioned robot joint module adopts a friction brake component 2, which has a permanent magnet built in it. When power is on, the coil generates magnetic force to offset the magnetic force of the permanent magnet, so that the robot joint module can operate normally. On the contrary, when the power is off, the coil is powered off and has no magnetic force to offset the magnetic force of the permanent magnet. The permanent magnet absorbs the brake spring to brake, that is, when the power is off, the brake pad 22 will automatically hold the brake body 23 for braking, thereby greatly improving safety and reliability. In addition, because the brake component 2 is arranged in the middle of the input shaft 41, during braking, the input shaft 41 is subjected to more balanced force, the shaft runout is smaller, and the braking stability is good. Moreover, because the brake body 23 extends to the outer surface of the shell 11 along the diameter direction, it is not only larger in size and higher in heat capacity, but also has fast heat dissipation, which greatly improves the adaptability of the robot joint module and improves reliability.

[0046] Reference Figure 1 , Figure 3 It can be seen that the outer surface of the shell 11 is provided with convex rib-shaped heat dissipation ribs, and the stator 13 is arranged on the inner wall of the shell 11. Therefore, the heat generated by the stator 13 during operation can be quickly dissipated through the heat dissipation ribs of the shell 11, and heat accumulation will not be generated in the joints, which greatly improves the working environment of the motor assembly 1 and the brake assembly 2. In addition, the heat dissipation ribs of the shell 11 can also play the role of reinforcing ribs. Under the premise of ensuring the strength of the shell 11, the weight of the shell 11 is reduced, which not only reduces the material cost of the shell 11, but also reduces the inertia of the joint when it moves with the robot arm, and reduces the control difficulty of the robot arm. In other embodiments, the heat dissipation ribs on the outer surface of the shell 11 can also be grille-shaped. In some other embodiments, the shell 11 and the brake body 23 are an integrated metal structure.

[0047] Reference Figure 3 , Figure 6 It can be seen that a mounting flange is provided at the lower end of the input shaft 41, the wave generator 34 is assembled on the mounting flange and forms a harmonic reducer 3 with the flexible wheel 31, the steel wheel 32 and the reducer bearing 33, and the upper end surface of the output shaft 45 flange is fixedly connected to the inner ring of the steel wheel 32 and the reducer bearing 33. Moreover, the outer edge of the flexible wheel 31 extends to the outer surface of the housing 11 along the diameter direction and is fixedly connected to the housing 11, the brake body 23 and the outer ring of the reducer bearing 33. A heat conductive adhesive is provided between the brake body 23 and the housing 11, and / or between the brake body 23 and the flexible wheel 31.

[0048] Through the above structure, the heat generated by the harmonic reducer 3 during operation can be transferred to the outer surface of the robot joint through the flexible wheel 31 on the one hand, and dissipated through the steel wheel 32 and the reducer bearing 33 on the other hand, and can also be dissipated through the flange-like structure at the lower end of the output shaft 45.

[0049] In summary, although the embodiment of the utility model adopts a friction brake component 2 that is very easy to generate a large amount of heat and the brake component 2 is arranged between the motor component 1 and the harmonic reducer 3, because heat dissipation ribs are arranged on the outer surface of the shell 11, the heat generated by the stator 13 can be quickly dissipated, and the outer edge of the brake body 23 of the brake component extends all the way to the outer edge of the shell 11. It has a high heat capacity and can also quickly dissipate the heat of the brake component. Coupled with the three-way heat dissipation route of the harmonic reducer 3, the heat dissipation capacity of the robot joint described in this embodiment is extremely excellent. Therefore, it can have the high safety and high reliability of the friction brake component 2, and will not cause the internal working environment of the robot joint to deteriorate due to heat accumulation.

[0050] As is known to all, the harmonic drive reducer relies on the wave generator 34 to assemble a flexible bearing to make the flexible wheel 31 produce controllable elastic deformation, and mesh with the rigid wheel to transmit the purpose of reduction transmission. In order to achieve controllable elastic deformation, it is necessary to take a variety of measures. On the one hand, the material of the flexible wheel 31 is set to a thin steel sheet, and the shape is set to a trumpet shape. Figure 5 It can be seen that the closer to the steel wheel 32, the larger the opening is. Therefore, the position of the wave generator 34 in the flexible wheel 31 needs to be kept constant. If the position is too low, it will easily cause the flexible wheel 31 to crack. If the position is too high, it will cause insufficient torque and fail to achieve the desired transmission efficiency. The wave generator 34 is assembled on the mounting flange at the lower end of the input shaft 41. Therefore, the assembly accuracy of the input shaft 41 in the vertical direction will directly affect the life and transmission efficiency of the harmonic reducer 3.

[0051] Reference Figure 2 , Figure 3 It can be seen that a positioning shoulder 411 is provided in the middle of the input shaft 41, and the brake pad fixing part 21 is sleeved on the input shaft 41 and the lower end face abuts against the positioning shoulder 411. The upper end of the input shaft 41 is provided with a first thread 412 matching the input locking nut 42, and the input locking nut 42 is connected to the upper end of the input shaft 41 through the first thread 412, and the lower end of the locking nut abuts against the upper end of the brake pad fixing part 21. It can be seen from the above structure that as long as the position accuracy of the positioning shoulder 411 on the input shaft 41, the length accuracy of the brake pad fixing part 21 and the height accuracy of the input locking nut 42 are ensured, the height accuracy of the top surface of the input locking nut 42 relative to the bottom surface of the wave generator 34 can be ensured.

[0052] An annular boss is provided at the upper end of the input locking nut 42, and an outer edge bearing mounting position and an inner edge bearing mounting position are respectively provided on the outer edge and inner edge of the annular boss. The inner ring of the first input bearing 43 is installed in the outer edge bearing mounting position, and the outer ring of the first input bearing 43 cooperates with the inner wall of the upper end of the shell 11. Therefore, as long as the assembly accuracy of the outer ring of the first input bearing 43 on the inner wall of the upper end of the shell 11 can be ensured, the assembly accuracy of the input shaft 41 in the vertical direction can be ensured, thereby ensuring that the wave generator 34 is installed in a suitable position.

[0053] As can be seen from the above, the robot joint described in this embodiment mainly ensures the installation accuracy of the wave generator 34 at the bottom end of the input shaft 41, the processing accuracy of the positioning shoulder 411 and the processing accuracy of the installation position of the first input bearing 43, and then cooperates with the high processing accuracy of the brake pad fixing 21 and the input locking nut 42 to ensure the assembly accuracy of the wave generator 34, which greatly reduces the difficulty of assembling the robot joint and reduces the errors caused by human factors, thereby ensuring the life and transmission efficiency of the harmonic reducer 3 and improving the product qualification rate.

[0054] Reference Figure 2 , Figure 4 and Figure 6 It can be seen that a second input bearing mounting position 441 for mounting a second input bearing 44 is provided on the lower end surface of the brake body 23. The inner ring of the second input bearing 44 is fixedly mounted on the input shaft 41. The second input bearing 44 is located at a position slightly lower than the middle of the input shaft 41, and cooperates with the first input bearing 43 located at the top of the input locking nut 42 to form a double bearing support for the input shaft 41. Since the braking surface of the brake assembly 2 and the rotor 12 of the motor assembly 1 are both arranged between the double bearings of the input shaft 41, the double bearing structure of the input shaft 41 can greatly improve the stability of the motor drive and braking, prevent the input shaft 41 from jumping or shaking, and greatly reduce the vibration of the input shaft 41.

[0055] Reference Figure 2 , Figure 3 , Figure 7It can be seen that the lower end of the output shaft 45 is a flange-shaped structure, and the upper end surface of the output shaft 45 flange is directly fixedly connected to the steel wheel 32 and the inner ring of the reducer bearing 33, that is, a bearing is arranged at the lower end of the output shaft 45. The upper end of the output shaft 45 is higher than the upper end of the input shaft 41, and a second thread 451 matching the output locking nut 46 is arranged at the upper end of the output shaft 45, and an output bearing mounting position is arranged at the outer edge of the output locking nut 46, and the first output bearing 47 is arranged at the output bearing mounting position and the inner edge bearing mounting position, that is, a bearing is arranged at the top end of the output shaft 45. Therefore, the output shaft 45 forms a double bearing support through the reducer bearing 33 and the first output bearing 47. This structure greatly reduces the vibration of the output shaft 45, and can effectively prevent the output shaft 45 from jumping or shaking, and ensure the coaxiality with the input shaft 41.

[0056] It can be seen from the above that the double bearing structure of the input shaft 41 and the double bearing structure of the output shaft 45 together constitute the four-bearing support structure of the robot joint described in this embodiment, which greatly improves the stress environment of the input shaft 41 and the output shaft 45, improves the coaxiality and stability of the input shaft 41 and the output shaft 45, reduces vibration during operation, and thus improves the control accuracy of the robot joint and extends the service life of the robot joint.

[0057] Reference Figure 2 It can be seen that sealing rings are provided between the flexible wheel 31 and the brake body 23, and between the steel wheel 32 and the flange structure of the output shaft 45, and the sealing rings between the flexible wheel 31 and the outer ring of the reducer, and between the steel wheel 32 and the inner ring of the reducer, constitute, Figure 8 , Fig. 9 It forms a seal for the grease in the harmonic reducer 3.

[0058] like Figure 2 , Figure 7 As shown, since the input shaft 41 and the output shaft 45 are coaxially sleeved together, in order to prevent the grease in the harmonic reducer 3 from leaking out from the gap between the inner surface of the input shaft 41 and the outer surface of the output shaft 45, a pressure difference sealing structure is provided between the inner surface of the input shaft 41 and the outer surface of the output shaft 45.

[0059] like Figure 7 , Figure 8 As shown, in the present embodiment, the pressure differential sealing structure includes three countersunk holes 51 formed on the inner surface of the input shaft 41, and the inner diameter of the countersunk holes 51 gradually decreases from bottom to top, and shaft shoulders 53 corresponding to the countersunk holes 51 are formed on the outer surface of the output shaft 45, and a sealing gap 5 is formed between the shaft shoulder 53 and the corresponding countersunk holes 51, and the size of the sealing gap 5 gradually decreases from bottom to top. In other embodiments, this sealing gap 5 may also remain unchanged.

[0060] When the robot joint is in operation, the grease penetrates into the sealing gap 5, and the input shaft 41 rotates at a high speed, thereby driving the grease attached to its inner wall to rotate along the outer edge of the output shaft 45 in the sealing gap 5; because the inner diameter of the counterbore 51 of the input shaft 41 gradually decreases from bottom to top, when the output shaft 45 rotates, the linear speed of the inner surface of the counterbore 51 also gradually decreases from bottom to top, and the speed of the driven grease in the sealing gap 5 also gradually decreases from bottom to top. According to the Bernoulli principle, the greater the flow rate, the smaller the pressure. Therefore, the pressure in the sealing gap 5 gradually increases from bottom to top, so that a pressure difference can be formed to form a pressure difference sealing structure.

[0061] The above-mentioned pressure differential sealing structure does not require additional sealing components between the input shaft 41 and the output shaft 45 , so there is no friction between the output shafts 45 , which improves the transmission efficiency, and the structure is highly reliable, requires almost no maintenance, and has a long service life.

[0062] Fig. 9 , Fig.10 Two cross-sectional schematic diagrams of another embodiment of the pressure differential sealing structure of the robot joint module according to the embodiment of the utility model. As shown in the figure, in this embodiment, the output shaft 45 is a straight shaft, and the counterbore 51 of the input shaft 41 and the outer surface of the output shaft 45 form a sealing gap 5 that gradually decreases from bottom to top;

[0063] Fig.10 , Fig.11 Two cross-sectional schematic diagrams of another embodiment of the pressure differential sealing structure of the robot joint module according to the embodiment of the utility model. As shown in the figure, in this embodiment, a frustum 52 is formed on the outer surface of the output shaft 45, and a sealing gap 5 which gradually decreases from bottom to top is formed between the counterbore 51 of the input shaft 41 and the frustum 52;

[0064] In some other embodiments, the pressure differential sealing structure is that a conical barrel-shaped through hole is formed on the inner surface of the input shaft 41, and the inner diameter of the through hole gradually decreases from bottom to top, and a cone 52 corresponding to the through hole is formed on the outer surface of the output shaft 45. At this time, the sealing gap 5 can be consistent from top to bottom, or can gradually decrease from bottom to top; or, a conical barrel-shaped through hole is formed on the inner surface of the input shaft 41, and the inner diameter of the through hole gradually decreases from bottom to top, the output shaft 45 is a straight shaft, and a sealing gap 5 is formed between the through hole and the outer surface of the output shaft 45.

[0065] The above is only a specific implementation of the utility model, but the protection scope of the utility model is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the utility model should be included in the protection scope of the utility model. Therefore, the protection scope of the utility model should be based on the protection scope of the claims.

Claims

1. A robot joint module with a sealing structure, characterized in that: The invention comprises a motor assembly (1), a brake assembly (2), a harmonic reducer (3) and a shaft assembly (4) which passes through the motor assembly (1), the brake assembly (2) and the harmonic reducer (3) and is arranged from top to bottom, wherein: The motor assembly (1) comprises a housing (11), a rotor (12), and a stator (13), wherein the housing (11) is a cylindrical metal structure, and the stator (13) is arranged on the inner wall of the housing (11); The brake assembly (2) comprises a brake pad (22), a brake pad fixing member (21), and a brake body (23), wherein the brake body (23) and the brake pad fixing member (21) are both flange-shaped structures, and the rotor (12) is sleeved on the brake pad fixing member (21); The harmonic reducer (3) comprises a flexible wheel (31), a steel wheel (32), a reducer bearing (33), and a wave generator (34). The shaft group (4) comprises an input shaft (41) and an output shaft (45) which are coaxially arranged, wherein the output shaft (45) is a hollow shaft, the input shaft (41) is sleeved on the output shaft (45), a mounting flange is arranged at the lower end of the input shaft (41), the wave generator (34) is assembled on the mounting flange and forms a harmonic reducer (3) together with the flexible wheel (31), the steel wheel (32) and the reducer bearing (33); a pressure difference sealing structure is arranged between the inner surface of the input shaft (41) and the outer surface of the output shaft (45).

2. The robot joint module with a sealing structure according to claim 1, characterized in that: The pressure differential sealing structure comprises at least two countersunk holes (51) formed on the inner surface of the input shaft (41), wherein the inner diameter of the countersunk holes (51) gradually decreases from bottom to top, and shaft shoulders (53) corresponding to the countersunk holes (51) are formed on the outer surface of the output shaft (45), and a sealing gap (5) is formed between the shaft shoulders (53) and the corresponding countersunk holes (51).

3. The robot joint module with a sealing structure according to claim 1, characterized in that: The pressure differential sealing structure is as follows: a conical barrel-shaped through hole is formed on the inner surface of the input shaft (41), and the inner diameter of the through hole gradually decreases from bottom to top; a frustum (52) corresponding to the through hole is formed on the outer surface of the output shaft (45); and a sealing gap (5) is formed between the through hole and the frustum (52).

4. The robot joint module with a sealing structure according to claim 2 or 3, characterized in that: The size of the sealing gap (5) remains consistent from bottom to top or gradually decreases from bottom to top.

5. The robot joint module with a sealing structure according to claim 1, characterized in that: The pressure differential sealing structure comprises: at least two countersunk holes (51) are formed on the inner surface of the input shaft (41), and the inner diameter of the countersunk holes (51) gradually decreases from bottom to top; a frustum (52) is formed on the outer surface of the output shaft (45); and a sealing gap (5) is formed between the countersunk holes (51) and the frustum (52).

6. The robot joint module with a sealing structure according to claim 1, characterized in that: The pressure differential sealing structure comprises: at least two countersunk holes (51) are formed on the inner surface of the input shaft (41), and the inner diameter of the countersunk holes (51) gradually decreases from bottom to top; the output shaft (45) is a straight shaft; and a sealing gap (5) is formed between the countersunk holes (51) and the outer surface of the output shaft (45).

7. The robot joint module with a sealing structure according to claim 1, characterized in that: A conical barrel-shaped through hole is formed on the inner surface of the input shaft (41), and the inner diameter of the through hole gradually decreases from bottom to top; the output shaft (45) is a straight shaft; and a sealing gap (5) is formed between the through hole and the outer surface of the output shaft (45).

8. The robot joint module with a sealing structure according to claim 1, characterized in that: The lower end of the output shaft (45) is a flange-shaped structure, and the upper end surface of the flange of the output shaft (45) is fixedly connected to the steel wheel (32) and the inner ring of the reducer bearing (33).

9. The robot joint module with a sealing structure according to claim 8, characterized in that: The brake pad fixing part and the brake body are both sleeved on the middle part of the input shaft (41), wherein the brake pad fixing part is fixed on the input shaft (41), the outer edge of the brake body extends to the outer surface of the shell (11) along the diameter direction and is fixedly connected to the shell (11), and the brake pad is connected to the lower end surface of the brake pad fixing part and forms a braking surface with the upper end surface of the brake body.

10. The robot joint module with a sealing structure according to claim 9, characterized in that: Sealing rings are provided between the flexible wheel (31) and the brake body, and between the steel wheel (32) and the flange-shaped structure of the output shaft (45).

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