Sealing device, equipment and robot equipped with same

Abstract

The present disclosure discloses a sealing device, an instrument, and a robot including the same. The sealing device is configured for use between a first member and a second member made of metal, and includes a first sealing assembly configured to sealingly connect to the first member and a second sealing assembly configured to sealingly connect to the second member. The first sealing assembly and the second sealing assembly are configured to form a dynamic seal with each other at at least one location in the circumferential direction of the first member and the second member. A portion where the first sealing assembly and the second sealing assembly contact each other is made of plastic. The instrument includes the sealing device. The robot includes a robot arm including at least a first link and the sealing device, where the first member is the first link and the second member is a second link connected to the first link, a base, or an end effector.

Description

[Technical Field]

[0001] The present disclosure relates to the technical field of mechanical seals, and more particularly to seals between links in mechanical devices such as robots. [Background technology]

[0002] Industrial robots are widely used in various industries, including welding, assembly, polishing, painting, medical surgery, agriculture, entertainment, and education. In practical applications, robots can be used both indoors and outdoors. In harsh working environments, robots have high requirements for protection and sealing performance. Failure to do so could result in dust, metal particles, or water penetrating the robot's body, causing corrosion and damage to the robot's joints and affecting its functionality. Furthermore, in specialized environments requiring high levels of cleanliness, such as medical care, food production, and precision electronics manufacturing, the robot itself must not generate contamination, otherwise the manufactured product could be contaminated. Therefore, the links of a robot arm must be sealed to prevent water, dust, and other contaminants from entering the robot's body and damaging it, or to prevent contaminants from leaking into the external environment, thereby meeting the cleanliness requirements of the application environment. Summary of the Invention [Means for solving the problem]

[0003] According to a first aspect of the present disclosure, there is provided a sealing device configured for use between a first member and a second member made of metal, the sealing device including a first sealing assembly configured to sealingly connect to the first member and a second sealing assembly configured to sealingly connect to the second member, the first sealing assembly and the second sealing assembly configured to form a dynamic seal with each other at at least one location around the circumference of the first member and the second member, and a portion of the first sealing assembly and the second sealing assembly where they contact each other is made of plastic.

[0004] In accordance with at least one embodiment of the present disclosure, the first seal assembly may be fixed and sealingly connected to the first member, and / or the second seal assembly may be fixed and sealingly connected to the second member.

[0005] According to at least one embodiment of the present disclosure, the first sealing assembly may include a first sealing portion and a second sealing portion. The first sealing portion may be provided between the first member and the second sealing portion and configured to seal the first member and the second sealing portion along a radial direction of the first member and the second member. The second sealing portion may be made of plastic.

[0006] According to at least one embodiment of the present disclosure, the stiffness of the material of the second sealing portion may be greater than the stiffness of the material of the first sealing portion.

[0007] According to at least one embodiment of the present disclosure, the second sealing assembly may include a third sealing portion and a fourth sealing portion. The third sealing portion may be provided between the second member and the fourth sealing portion and configured to seal the second member and the fourth sealing portion along the radial and axial directions of the first member and the second member. The fourth sealing portion may be made of plastic and configured to form a dynamic seal with the second sealing portion at at least one location in the circumferential direction of the first member and the second member.

[0008] According to at least one embodiment of the present disclosure, the fourth sealing portion may have a stiffness greater than the stiffness of the third sealing portion.

[0009] According to at least one embodiment of the present disclosure, a recess may be formed in one of the second sealing portion and the fourth sealing portion, and a protrusion may be formed in the other of the second sealing portion and the fourth sealing portion. The protrusion may be inserted into and contact the recess to form a dynamic seal at at least one location in the circumferential direction of the first member and the second member.

[0010] According to at least one embodiment of the present disclosure, the contact between the recess and the protrusion may be substantially a line contact.

[0011] According to at least one embodiment of the present disclosure, a side surface or a portion of a side surface of the recess may be a flat surface, and the protrusion may have a smooth surface that contacts the flat surface. Alternatively, a side surface or a portion of a side surface of the recess may be a smooth surface, and the protrusion may have a flat surface that contacts the smooth surface. Alternatively, a side surface or a portion of a side surface of the recess may be a smooth surface, and the protrusion may have a smooth surface that contacts the smooth surface.

[0012] According to at least one embodiment of the present disclosure, the first sealing portion may include an O-ring, an annular sealing gasket, or a U-ring mounted between the second sealing portion and the first member, the second sealing portion may include a pressure ring, and the first sealing portion may be made of rubber.

[0013] According to at least one embodiment of the present disclosure, the second sealing portion and / or the first member may have an annular groove formed therein, and the first sealing portion may be disposed within the annular groove to seal the first member. The first member may have a first shoulder formed therein, and the second sealing portion may be attached to the first shoulder.

[0014] According to at least one embodiment of the present disclosure, the third sealing portion may include a U-ring attached between the fourth sealing portion and the second member, and the fourth sealing portion may include a pressure ring. The third sealing portion may be made of rubber.

[0015] According to at least one embodiment of the present disclosure, an annular groove may be formed in the fourth sealing portion and / or the second member, the third sealing portion may be disposed within the annular groove to seal the second member, a second shoulder may be formed in the second member, and the third sealing portion may be attached to the second shoulder.

[0016] According to at least one embodiment of the present disclosure, the first sealing portion may include an O-ring and may be disposed between the first member and the second sealing portion, the third sealing portion may include a U-ring, and the fourth sealing portion may be disposed between the third sealing portion and the second sealing portion.

[0017] According to at least one embodiment of the present disclosure, the plastic may include at least one of PVCTE, polyvinyl chloride, polypropylene, polyethylene, polybutene, acrylonitrile-butadiene-styrene copolymer, or polytetrafluoroethylene.

[0018] According to a second aspect of the present disclosure, there is provided a device including a first member and a second member made of metal, and the sealing device provided between the first member and the second member.

[0019] According to a third aspect of the present disclosure, there is provided a robot including a robot arm, the robot arm including at least a first member and a second member made of metal, and the sealing device provided between the first member and the second member, the first member may be a first robot arm link, the second member may be a second robot arm link, a base, or an end effector, and the second member may be rotatably connected to the first member.

[0020] According to at least one embodiment of the present disclosure, the first sealing assembly may include a first sealing portion and a second sealing portion, the first sealing portion may be disposed between the first member and the second sealing portion and configured to seal the first member and the second sealing portion along a radial direction of the first member and the second member, and the second sealing portion may be made of plastic and may be fixedly connected to the first member.

[0021] According to at least one embodiment of the present disclosure, the second sealing assembly may include a third sealing portion and a fourth sealing portion, the third sealing portion may be disposed between the second member and the fourth sealing portion and configured to seal the second member and the fourth sealing portion along the radial and axial directions of the first member and the second member, the fourth sealing portion may be made of plastic and may be configured to form a dynamic seal with the second sealing portion at at least one location in the circumferential direction of the first member and the second member.

[0022] According to at least one embodiment of the present disclosure, the fourth sealing portion may be fixedly connected to the second member. [Brief explanation of the drawings]

[0023] In order to more clearly describe the embodiments of the present disclosure or the technical solutions in the prior art, the drawings necessary for describing the embodiments or the prior art will be briefly described below. Obviously, the drawings in the following description are only embodiments of the present disclosure, and those skilled in the art can obtain other drawings based on the disclosed drawings without any creative efforts. [Figure 1] FIG. 1 is a perspective view illustrating a robot having a robotic arm according to one embodiment of the present disclosure. [Figure 2] FIG. 1 is a front view illustrating a sealing device according to one embodiment of the present disclosure. [Figure 3] FIG. 3 is a cross-sectional view showing the sealing device taken along line AA in FIG. 2. [Figure 4]4 is a partially enlarged cross-sectional view of a portion B of the sealing device shown in FIG. 3. FIG. [Figure 5] FIG. 3 is an exploded schematic view of the sealing device shown in FIG. 2. DETAILED DESCRIPTION OF THE INVENTION

[0024] Hereinafter, the technical solutions of the embodiments of the present disclosure will be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present disclosure, but not all of the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present disclosure without creative efforts fall within the scope of protection of the present disclosure. Furthermore, the drawings are not necessarily drawn to scale for clarity, and unnecessary details may be omitted to avoid obscuring the claimed subject matter.

[0025] 1 to 5, a sealing device 300 according to the present disclosure, for example, used between two links of a robot arm 100 of a robot 1000, will be described in detail below. Hereinafter, an embodiment of the sealing device according to the present disclosure will be described using two links of the robot arm 100 of the robot 1000 as an example. However, those skilled in the art will understand that the sealing device according to the present disclosure may be applied between any two members that need to be sealingly connected to each other, and in particular, may be applied between a first member and a second member that are rotationally connected to each other. It should be understood that the sealing device according to the present disclosure is not limited to being applied between two adjacent links of a robot arm 100 or to a robot arm of a robot, but may be applied to any equipment having similar sealing requirements.

[0026] 1 , the robot 1000 includes a robot arm 100 and an end effector 200 attached to the end of the robot arm 100, where the robot arm 100 includes a base 60 and a plurality of links connected to each other via joints. Specifically, in this embodiment, the plurality of links include a first link 10, a second link 20, a third link 30, a fourth link 40, and a fifth link 50. The robot arm 100 rotates each link around its own rotation axis by the action of a driving device, for example, a motor and a reducer, so that the end effector 200 attached to the end of the robot arm 100 reaches a desired position and performs a corresponding operation.

[0027] The motor and reducer may be formed as a joint (not shown), and the joint may be attached between adjacent links, thereby adjusting the rotation of the link by controlling the rotation speed of the motor and reducer. A plurality of joints may be provided based on the number of links in the robot arm 100. For example, the robot arm 100 of the robot shown in FIG. 1 may include six joints. More specifically, the first joint is provided between the base 60 and the first link 10, the second joint is provided between the first link 10 and the second link 20, the third joint is provided between the second link 20 and the third link 30, the fourth joint is provided between the third link 30 and the fourth link 40, the fifth joint is provided between the fourth link 40 and the fifth link 50, and the sixth joint is provided between the fifth link 50 and the end effector 200. By controlling the rotation of the motor and reducer in each joint, the position of the robot arm 100 and the end effector 200 can be changed as needed, thereby achieving the desired operation of the end effector 200.

[0028] To prevent contaminants in the working environment from entering the robot body and contaminants inside the robot from leaking into the external environment, appropriate sealing devices must be provided between each link, between the link and the base, and between the link and the end effector.

[0029] A sealing device 300 according to an embodiment of the present disclosure will be described in detail below with reference to FIGS. 2 to 5. The sealing device 300 is applied between each link of the robot arm 100, between the link and the base 60, and between the link and the end effector 200. In the following description, for ease of understanding, a sealing device 300 provided between two adjacent links will be described as an example, with one of the two adjacent links being a first member 1 and the other link being a second member 2. Note that in order to clearly show the specific structure of the sealing device 300 provided between the two links, the structure of the links will be shown in a simplified schematic form.

[0030] 2 to 4, the sealing device 300 includes a first sealing assembly 310 and a second sealing assembly 320 disposed between a first member 1 and a second member 2. The first sealing assembly 310 is connected to the first member 1, and the second sealing assembly 320 is connected to the second member 2, and a dynamic seal is formed between the first sealing assembly 310 and the second sealing assembly 320 in at least one circumferential direction. In an embodiment according to the present disclosure, the first sealing assembly 310 and the first member 1 are fixedly and sealingly connected by a frictional force, and the second sealing assembly 320 and the second member 2 are also fixedly and sealingly connected by a frictional force.

[0031] More specifically, the first sealing assembly 310 includes a first sealing portion 3 and a second sealing portion 4, and the second sealing assembly 320 includes a third sealing portion 6 and a fourth sealing portion 5. As shown in FIG. 4 , the first sealing portion 3 is an O-ring, and the second sealing portion 4 is a pressure ring with an annular groove 401 formed on its outer surface. The first sealing portion 3 is mounted in the annular groove 401 and is interposed between the inner wall of the first member 1 and the second sealing portion 4. A first shoulder 101 is formed on the inner surface of the first member 1, and one end of the second sealing portion 4 adjacent to the sealing groove 401 is mounted in contact with the first shoulder 101. When the first sealing assembly 310 is mounted to the first member 1, a certain deformation occurs in at least the first sealing portion 3, thereby forming a fixed connection between the first sealing assembly 310 and the first member 1 by frictional sealing. As a result, when the first member 1 rotates, the first sealing assembly 310 rotates accordingly. In the above-described embodiment, the first sealing portion 3 and the second sealing portion 4 are formed separately, but they may also be formed as an integrated structure. In one embodiment, the first sealing portion 3 and the second sealing portion 4 may be formed of different materials. For example, the first sealing portion 3 is formed of rubber, and the second sealing portion 4 is formed of PVCTE. PVCTE is an elastomer formed by mixing polyvinyl chloride and rubber. However, the first sealing portion 3 and the second sealing portion 4 may also be formed of the same material. For example, both sealing portions 3 and 4 may be formed of PVCTE. In some embodiments, the rigidity of the material of the second sealing portion 4 is greater than the rigidity of the material of the first sealing portion 3, thereby providing a more effective sealing effect. As shown in FIGS. 3 to 5 , the third sealing portion 6 may be formed as a U-ring. 4 and 5, the third sealing portion 6 is a U-ring having a U-shaped cross section, and its opening 601 faces the inner wall of the second member 2, and the fourth sealing portion 5 is a pressure ring. A second shoulder 201 is formed on the inner side of the second member 2, and the third sealing portion 6 is attached by abutting against the second shoulder 201.The fourth sealing portion 5 is disposed between the second sealing portion 3 and the third sealing portion 6, so that when the fourth sealing portion 5 applies pressure to the third sealing portion 6, at least the third sealing portion 6 undergoes a certain deformation, forming a fixed sealing connection between the third sealing portion 6 and the second member 2. As a result, when the second member 2 rotates relative to the first member 1, the second sealing assembly 320 can rotate together with the second member 2 due to the action of frictional force.

[0032] In one embodiment, the third sealing portion 6 and the fourth sealing portion 5 may be formed of different materials, for example, the third sealing portion 6 is formed of rubber and the fourth sealing portion 5 is formed of PVCTE. However, the third sealing portion 6 and the fourth sealing portion 5 may be formed of the same material, for example, both are formed of PVCTE. In some embodiments, the stiffness of the material of the fourth sealing portion 5 is greater than the stiffness of the material of the third sealing portion 6, thereby providing a better sealing effect.

[0033] It should be noted that a dynamic seal, such as a line seal, a face seal, and / or a combination of a line seal and a face seal, is formed between the first seal assembly 310 and the second seal assembly 320 in the circumferential direction.

[0034] 4 , a recess 402 may be formed at a lower end of the first sealing assembly 310 (e.g., a lower end of the second sealing portion 4), and a cross section of the recess 402 may be formed as one of a rectangle, a trapezoid, a V-shape, a U-shape, a W-shape, or a semicircle. Correspondingly, a protrusion 502 may be formed at an upper end of the second sealing assembly 320 (e.g., an upper end of the fourth sealing portion 5), and a cross section of the protrusion 502 may be formed as one of a rectangle, a trapezoid, a V-shape, a U-shape, a W-shape, or a semicircle. When the protrusion 502 is inserted into the recess 402, a dynamic seal may be formed between the first sealing assembly 310 and the second sealing assembly 320 at at least one location in the circumferential direction. For example, as shown in FIG. 4 , the cross section of recess 402 is V-shaped, and the cross section of protrusion 502 is semicircular, so that the surfaces on both sides of recess 402 can be sealed by protrusion 502, thereby forming two line seals. Depending on the respective shapes of protrusion 502 and recess 402 and the nature of the contact therebetween (line contact or surface contact), various forms of sealing devices may be formed between first sealing assembly 310 and second sealing assembly 320, such as a surface seal, a line seal, or a combination thereof. Here, line contact includes not only ideal line contact but also contact in which the contact surface is narrow and approximately linear (i.e., contact in which the width of the contact surface is negligible). For this purpose, the line contact referred to herein may be referred to as an approximate line contact or a substantially line contact.

[0035] If the recess and protrusion do not perfectly match, a linear seal is likely to form between them. Linear sealing reduces the contact area between the first seal assembly 310 and the second seal assembly 320, reducing friction and wear, which is advantageous for extending the service life of the seal assemblies 310 and 320 and facilitating removal and replacement of the sealing device. Surface sealing or a combination of surface and linear sealing is also possible in place of a linear seal. Whether a surface seal, a linear seal, or a combination of both is used, the frictional force generated by it is acceptable as long as it is suitable for forming a dynamic seal between the first seal assembly 310 and the second seal assembly 320.

[0036] The shapes of the recess 402 and the protrusion 502 are not limited to those listed above. Generally, the side surface or a portion of the side surface of the recess 402 may be a flat surface, and the protrusion 502 may have a smooth surface that contacts the flat surface. Alternatively, the side surface or a portion of the side surface of the recess 402 may be a flat surface, and the protrusion 502 may have a flat surface that contacts the flat surface. Alternatively, the side surface or a portion of the side surface of the recess 402 may be a smooth surface, and the protrusion 502 may have a flat surface that contacts the smooth surface. Alternatively, the side surface or a portion of the side surface of the recess 402 may be a smooth surface, and the protrusion 502 may have a smooth surface that contacts the smooth surface. This allows various types of seals to be formed between the first seal assembly 310 and the second seal assembly 320 depending on the sealing requirements.

[0037] In some of the embodiments described above, both the second sealing portion 3 and the fourth sealing portion 5 are made of plastic, such as PVCTE, but the present disclosure is not limited thereto. In other embodiments, only the portions of the first sealing assembly and the second sealing assembly that contact each other may be made of plastic. In addition to the above-mentioned PVCTE, other suitable materials such as polyvinyl chloride (PVC), polypropylene (PP), polyethylene (PE), polybutene (PB), acrylonitrile butadiene styrene (ABS), polytetrafluoroethylene (PTFE) or similar plastics are also suitable for forming at least the contacting portions of the protrusions 502 and recesses 402, for forming all of the protrusions 502 and recesses 402, for forming the entire second sealing portion 3 and the entire fourth sealing portion 5, or as a coating material for the contacting portions of the protrusions 502 and recesses 402.

[0038] However, the present disclosure is not limited thereto. A recess may be formed at the upper end of the second sealing assembly 320 (e.g., the upper end of the fourth sealing portion 5), and a protrusion may be formed at the lower end of the first sealing assembly 310 (e.g., the lower end of the second sealing portion 4). Furthermore, the first sealing assembly 310 and the second sealing assembly 320 may use the same sealing structure, except for the engaging recess and protrusion. For example, the first sealing assembly 310 and the second sealing assembly 320 may both use a combination of an O-ring and a pressure ring, or both use a combination of a U-ring and a pressure ring, or both use an annular seal gasket and a pressure ring, where a pair of pressure rings (i.e., the second sealing portion 4 and the fourth sealing portion 5) face each other and engage with each other via the recess and protrusion to form a seal.

[0039] In the above description, the protrusion 502 is provided at the upper end of the second seal assembly 320, and the recess 402 is provided at the lower end of the first seal assembly, and they face each other. However, if necessary, the protrusion may protrude radially outward or inward relative to the first and second members, and the recess may be formed accordingly.

[0040] In another embodiment, the first sealing assembly 310 does not seal with the inner wall of the first member 1, but seals with the outer wall or end surface of the first member 1. That is, the first sealing unit 3 may be configured to seal at least one of the inner, outer, or end surface of the first member 1, as needed. Similarly, the second sealing assembly 320 may be configured to seal not only with the inner wall of the second member 2, but also with the outer wall or end surface of the second member 2. That is, the third sealing unit 6 may be configured to seal at least one of the inner, outer, or end surface of the second member 2. Based on the above description, those skilled in the art will know how to seal the outer wall or end surface of the first member 1 or the second member 2 using a combination of a pressure ring and an O-ring, a sealing gasket, or a U-ring, and the description will be omitted here.

[0041] Although the third sealing portion 6 has been described using a U-ring having a U-shaped cross section as an example, the present disclosure is not limited thereto. First, as described above, an annular seal gasket or an O-ring (i.e., a sealing ring having a circular cross section) may be used as the third sealing portion 6 instead of a U-ring. Furthermore, the shape of the opening 601 of the U-ring is not limited to a U-shape and may be various shapes, such as rectangular, V-shaped, T-shaped, W-shaped, or semicircular. This allows one or more annular grooves to be formed on the inner periphery, outer periphery, or one or both end faces of the sealing ring. The presence of the annular grooves, i.e., the openings 601, allows the third sealing portion 6 to be easily deformed by the pressure of the pressure ring, thereby easily forming a tight seal between the second member 2 and the third sealing portion 6 with a small amount of pressure.

[0042] The sealing device according to the present disclosure described above forms a sealed connection between the first sealing assembly and the first member, between the second sealing assembly and the second member, and between the first sealing assembly and the second sealing assembly, thereby providing good isolation between the inside and outside of the robot arm 100. In addition, the sealing device can convert friction between the links into friction between the sealing members and can also achieve linear friction between the sealing members, thereby ensuring sealing and significantly reducing the frictional resistance of movement.

[0043] In equipment such as a robot with a robot arm, the first member 1 and the second member 2 are generally made of a metal material. By applying the sealing device according to the present disclosure, a pair of pressure rings can be made of PVCTE, thereby avoiding relative friction between the plastic member made of PVCTE and the metal member and reducing wear on the link. Furthermore, friction loss between plastic members such as pressure rings made of PVCTE is small, and even if they wear, chipping is unlikely to occur. Replacement costs are low and replacement is easy.

[0044] While the first and second sealing assemblies and the corresponding connections between the first and second members have been described using sealing members such as O-rings, U-rings, and annular sealing gaskets, those skilled in the art should understand that the present disclosure is not limited thereto. For example, the first sealing assembly can be fixedly connected to the first member by a first sealing portion and a key, screw, pin, threaded connection, or similar removable connecting member, thereby allowing the first sealing assembly and the first member to rotate rigidly and synchronously without relative motion. Similarly, the second sealing assembly can be fixedly connected to the second member by a third sealing portion and a key, screw, pin, threaded connection, or similar removable connecting member, thereby allowing the second sealing assembly and the second member to rotate rigidly and synchronously without relative motion.

[0045] When the sealing device in the embodiments of the present disclosure is applied between links of a robot, between a link and a base, and / or between a link and an end effector, it can not only effectively prevent external water and dust from entering the inside of the robot, but also effectively prevent contaminants such as grease and dust inside the robot from entering the external environment, thereby achieving a high level of dynamic sealing.

[0046] By selecting a material with wear resistance and a low friction coefficient, such as PTV, to form a pair of relatively rotating pressure rings, the sealing device can achieve low friction and wear while still ensuring sealing performance, which is more advantageous for robot motion control.

[0047] By utilizing the structural characteristics of a U-ring with an annular opening, it is possible to reduce the positive pressure at the sealing contact surface with a small amount of deformation, which helps to reduce frictional forces during relative movement of the links and is therefore advantageous for robot motion control. In the embodiment described with reference to the drawings, the O-ring on one side of the first sealing assembly ensures radial and / or axial sealing of the first member depending on its installation position, while the U-ring on the other side of the second sealing assembly ensures radial sealing against the second member and, since it is also subjected to axial pressure, also ensures axial sealing. Therefore, the combined use of an O-ring and a U-ring in a sealing device is particularly suitable for use between two links of a robot arm.

[0048] When an O-ring is used to seal the first member radially and a U-ring is used to seal the second member axially and radially, the pressure between the first and second sealing assemblies only needs to satisfy the axial pressure required for sealing the U-ring. This sealing structure is advantageous in reducing the frictional force between the first and second sealing assemblies and achieving dynamic sealing.

[0049] Considering that materials such as PTV belong to the plastic category, the sealing device is less likely to generate dust particles even when operated for a long time, and is therefore more suitable for special cases where high cleanliness is required.

[0050] Although several embodiments of the present disclosure have been described above, the technical features of the above-described embodiments can be arbitrarily combined. For the sake of brevity, not all combinations of the technical features in the above-described embodiments are described, but combinations of these technical features should be considered within the scope described in this specification unless they are inconsistent.

[0051] The above examples merely illustrate some embodiments of the present disclosure, and although the descriptions are specific and detailed, they should not be construed as limiting the scope of protection of the invention. Those skilled in the art may make minor modifications and improvements without departing from the spirit of the present disclosure, and all of these modifications and improvements are within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined in accordance with the claims.

Claims

1. 1. A sealing device configured for use between a first member and a second member made of metal, comprising: a first seal assembly configured to sealingly connect to the first member; a second seal assembly configured to sealingly connect to the second member; the first sealing assembly and the second sealing assembly are configured to form a dynamic seal with each other at at least one location around the circumference of the first member and the second member; A sealing device, characterized in that a portion where the first sealing assembly and the second sealing assembly contact each other is made of plastic.

2. the first seal assembly is fixedly and sealingly connected to the first member; and / or 10. The sealing device of claim 1, wherein the second sealing assembly is fixedly and sealingly connected to the second member.

3. the first seal assembly includes a first seal portion and a second seal portion; the first sealing portion is provided between the first member and the second sealing portion, and is configured to seal the first member and the second sealing portion along a radial direction of the first member and the second member; The sealing device according to claim 1 , wherein the second sealing portion is made of plastic.

4. The sealing device according to claim 3 , wherein the rigidity of the material of the second sealing portion is greater than the rigidity of the material of the first sealing portion.

5. the second seal assembly includes a third seal portion and a fourth seal portion; the third sealing portion is provided between the second member and the fourth sealing portion and is configured to seal the second member and the fourth sealing portion along the radial direction and the axial direction of the first member and the second member, 4. The sealing device of claim 3, wherein the fourth sealing portion is made of plastic and is configured to form a dynamic seal with the second sealing portion at at least one location in the circumferential direction of the first member and the second member.

6. The sealing device according to claim 5 , wherein the fourth sealing portion has a rigidity greater than that of the third sealing portion.

7. 6. The sealing device according to claim 5, wherein a recess is formed in one of the second sealing portion and the fourth sealing portion, and a protrusion is formed in the other of the second sealing portion and the fourth sealing portion, and the protrusion is inserted into and contacts the recess, forming a dynamic seal at at least one location in the circumferential direction of the first member and the second member.

8. The sealing device according to claim 7 , wherein the contact between the recess and the protrusion is substantially a line contact.

9. The side or part of the side of the recess is a flat surface, and the protrusion has a smooth surface that contacts the flat surface, or The side surface or a part of the side surface of the recess is a smooth surface, and the protrusion has a flat surface that contacts the smooth surface, or The sealing device according to claim 7 , wherein a side surface or a part of a side surface of the recess is a smooth surface, and the protrusion has a smooth surface that contacts the smooth surface.

10. 4. The sealing device of claim 3, wherein the first sealing portion includes an O-ring, an annular seal gasket, or a U-ring mounted between the second sealing portion and the first member, the second sealing portion includes a pressure ring, and the first sealing portion is made of rubber.

11. an annular groove is formed in the second sealing portion and / or the first member, and the first sealing portion is provided in the annular groove to seal the first member; 11. The sealing device of claim 10, wherein the first member defines a first shoulder, and the second sealing portion is attached to the first shoulder.

12. 5. The sealing device of claim 4, wherein the third sealing portion includes a U-ring attached between the fourth sealing portion and the second member, the fourth sealing portion includes a pressure ring, and the third sealing portion is made of rubber.

13. 13. The sealing device of claim 12, wherein an annular groove is formed in the fourth sealing portion and / or the second member, the third sealing portion is provided in the annular groove to seal the second member, a second shoulder is formed in the second member, and the third sealing portion is attached to the second shoulder.

14. the first sealing portion includes an O-ring and is provided between the first member and the second sealing portion; The sealing device according to claim 4 , wherein the third sealing portion includes a U-ring, and the fourth sealing portion is disposed between the third sealing portion and the second sealing portion.

15. 10. The sealing device of claim 1, wherein the plastic comprises at least one of PVCTE, polyvinyl chloride, polypropylene, polyethylene, polybutene, acrylonitrile-butadiene-styrene copolymer, or polytetrafluoroethylene.

16. 10. An apparatus comprising: first and second metallic members; and a sealing device according to claim 1 disposed between the first and second members.

17. 1. A robot including a robotic arm, the robot arm includes a first member and a second member made of metal, and the sealing device according to claim 1 disposed between the first member and the second member; 1. A robot comprising: a first member that is a first robot arm link; a second member that is a second robot arm link, a base, or an end effector; and a second member that is rotatably connected to the first member.

18. 18. The robot of claim 17, wherein the first sealing assembly includes a first sealing portion and a second sealing portion, the first sealing portion being disposed between the first member and the second sealing portion and configured to seal the first member and the second sealing portion along a radial direction of the first member and the second member, and the second sealing portion being made of plastic and fixedly connected to the first member.

19. the second sealing assembly includes a third sealing portion and a fourth sealing portion, the third sealing portion being disposed between the second member and the fourth sealing portion and configured to seal the second member and the fourth sealing portion along radial and axial directions of the first member and the second member; 20. The robot of claim 18, wherein the fourth seal is made of plastic and is configured to form a dynamic seal with the second seal at at least one location around the circumference of the first member and the second member.

20. 20. The robot of claim 18, wherein the fourth sealing portion is fixedly connected to the second member.

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