Sealing structure of a robot wrist
By setting an annular baffle and a cable outlet tube inside the mounting hole of the robot wrist, combined with rolling bearings, a stable sealing structure is formed, which solves the problem of insufficient sealing stability in the prior art and achieves stable sealing effect and smooth rotation of the robot wrist.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- ZHEJIANG QIANJIANG ROBOT CO LTD
- Filing Date
- 2025-07-25
- Publication Date
- 2026-07-14
AI Technical Summary
The existing robot wrist structure has insufficient sealing stability, especially the second oil seal, which is prone to deformation and axial movement under external gas and liquid pressure, resulting in unstable sealing performance.
An annular retaining edge is provided on the inner edge of the mounting hole, and the oil seal ring is embedded in the mounting hole with the open side facing the wrist housing side. Combined with the cable outlet and rolling bearing, a stable sealing structure is formed. The retaining edge is used to constrain the axial position of the oil seal ring, reducing the risk of deformation and dislodgement.
It effectively reduces the degree of annular deformation of the oil seal, maintains sealing stability, avoids seal failure, and ensures smooth rotation and sealing effect of the robot wrist.
Smart Images
Figure CN224489188U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the field of robotics technology and relates to a sealing structure for a robot wrist. Background Technology
[0002] The robot's wrist shell can rotate and swing relative to the housing to meet the needs of picking up objects at different angles. In order to prevent external dust, gas and liquid from entering the housing and affecting the normal operation of the robot, a sealing structure is usually required at the joint between the housing and the wrist.
[0003] Patent application CN202222027842.9 discloses a robot wrist structure, including a wrist body and a reducer end assembly and a support end assembly respectively disposed on opposite sides of the wrist body; the wrist body is rotatable relative to the reducer end assembly and the support end assembly. The support end assembly includes a second oil seal shaft and a second oil seal sleeved on the second oil seal shaft; the second oil seal shaft is fixedly connected to the forearm body; the second oil seal is located between the second oil seal shaft and the wrist body.
[0004] The wrist structure of the robot mentioned above still has shortcomings: the opening side of its second oil seal is set inward toward the forearm body, which is prone to deformation after being subjected to external gas and liquid pressure, and the second oil seal may move axially and come into contact with the wrist body, causing wear at the end and affecting the stability of the sealing effect. Summary of the Invention
[0005] This invention addresses the aforementioned problems in existing technologies by providing a sealing structure for a robot wrist. The technical problem this invention aims to solve is that the sealing stability of existing wrist structures is insufficient.
[0006] The objective of this utility model can be achieved through the following technical solutions:
[0007] A sealing structure for a robot wrist, the wrist comprising a housing and a wrist shell, the housing having a mounting hole, the sealing structure comprising an oil seal ring with a U-shaped cross-section, characterized in that the inner edge of the mounting hole has an annular retaining edge, the oil seal ring is embedded in the mounting hole and the outer edge of the oil seal ring abuts against the inner edge of the mounting hole, the open side of the oil seal ring is disposed along the axial direction of the mounting hole toward the wrist shell and abuts against the retaining edge, the outer side of the wrist shell has an annular cable outlet tube, the cable outlet tube is rotatably inserted into the mounting hole and the oil seal ring is sleeved on the outer periphery of the cable outlet tube.
[0008] By setting an annular retaining edge on the inner edge of the mounting hole and embedding the oil seal ring inside the mounting hole to form a seal between the outer edge and the inner wall of the mounting hole, and by fitting the oil seal ring onto the outer circumference of the cable outlet tube on the wrist housing to form a seal, and by setting the open side of the oil seal ring to face the wrist housing and abutting against the retaining edge, under the condition that the rotating connection between the housing and the wrist housing is sealed by the oil seal ring, the open side of the oil seal ring facing the wrist housing, i.e. the side connected to the outside, allows gas and liquid impacting the oil seal ring to enter the inner cavity of the oil seal ring and generate a radially expanding force on the oil seal ring. This force is offset by the inner wall of the mounting hole and the outer wall of the cable outlet tube, reducing the degree of deformation of the oil seal ring and ensuring its positional stability. At the same time, the retaining edge can constrain the axial position of the oil seal ring, preventing it from deforming under force and falling out to the outside along the cable outlet tube, which would lead to seal failure. This effectively ensures the sealing stability of the robot wrist.
[0009] In the sealing structure of the robot wrist described above, the wrist also includes a rolling bearing, which is embedded in the mounting hole and sleeved on the outer periphery of the cable outlet tube. The oil seal ring is located axially between the rolling bearing and the retaining edge. In this way, the rolling bearing can effectively reduce the resistance to the rotation of the wrist and the housing relative to the box. Simultaneously, the rolling bearing, in conjunction with the retaining edge, restricts the axial position of the oil seal ring, keeping it in its working position to stably perform its sealing function.
[0010] In the sealing structure of the aforementioned robot wrist, the oil seal ring includes an outer ring and an inner ring, both annular and coaxially arranged. The inner ring is fitted around the outer circumference of the cable outlet tube. An annular inner liner, coaxially arranged with the oil seal ring, is embedded on the outer circumferential surface of the inner ring. The inner liner is made of a rigid material. This inner liner increases the radial stiffness of the side of the oil seal ring that is in contact with the cable outlet tube, ensuring a stable fit between the oil seal ring and the cable outlet tube. This prevents radial inward deformation of the oil seal ring from affecting the sealing effect, resulting in a more stable seal.
[0011] In the sealing structure of the robot wrist described above, the inner edge of the inner ring has an annular protrusion. This protrusion corresponds to the position of the inner liner frame along the radial direction of the oil seal ring, and is fitted onto the outer periphery of the cable outlet tube. This allows the protrusion to fill the space between the inner liner frame and the outer periphery of the cable outlet tube, continuously compensating for frictional losses with the cable outlet tube, thereby maintaining a stable sealing contact effect. Simultaneously, it avoids excessive frictional resistance between the oil seal ring and the cable outlet tube, ensuring smooth rotation of the wrist housing.
[0012] In the sealing structure of the robot wrist described above, the inner diameter of the retaining edge is larger than the inner diameter of the oil seal ring. This helps to limit the movement of the oil seal ring while ensuring that there is a certain clearance space between the inner edge of the retaining edge and the cable outlet tube, reducing the probability of scratching interference between the wrist housing and the retaining edge during rotation.
[0013] Compared with the prior art, the advantages of this utility model are as follows:
[0014] The sealing structure of this robot wrist effectively reduces the degree of deformation that the oil seal ring may undergo, ensuring its positional stability. At the same time, the retaining edge can constrain the axial position of the oil seal ring, preventing it from deforming under stress and coming off along the cable tube to the outside, thus preventing seal failure. This effectively ensures the sealing stability of the robot wrist. Attached Figure Description
[0015] Figure 1 This is a three-dimensional structural diagram of the robot wrist in this embodiment.
[0016] Figure 2 This is a front view structural diagram of the robot wrist in this embodiment.
[0017] Figure 3 yes Figure 2 A schematic diagram of the AA cross section.
[0018] Figure 4 yes Figure 3 Enlarged view of part B in the image.
[0019] In the diagram, 1 is the housing; 11 is the mounting hole; 12 is the retaining edge; 2 is the wrist housing; 21 is the cable outlet tube; 3 is the oil seal ring; 31 is the outer ring; 32 is the inner ring; 321 is the protruding rib; 4 is the rolling bearing; and 5 is the inner liner frame. Detailed Implementation
[0020] The following are specific embodiments of the present invention, which are described in conjunction with the accompanying drawings. However, the present invention is not limited to these embodiments.
[0021] like Figure 1-3 As shown, the robot wrist includes a housing 1 and a wrist shell 2. The outer side of the wrist shell 2 has an annular cable outlet tube 21, which is rotatably inserted into the housing 1.
[0022] like Figure 4As shown, the housing 1 has a mounting hole 11. The sealing structure includes an oil seal ring 3 with a U-shaped cross-section. The oil seal ring 3 is made of elastic material. The inner edge of the mounting hole 11 has an annular retaining edge 12. The oil seal ring 3 is embedded in the mounting hole 11, and its outer edge seals against the inner edge of the mounting hole 11. The open side of the oil seal ring 3 is positioned along the axial direction of the mounting hole 11 towards the wrist housing 2 and is limited and abuts against the retaining edge 12. The inner diameter of the retaining edge 12 is larger than the inner diameter of the oil seal ring 3. The cable outlet 21 is located in the mounting hole 11, and the oil seal ring 3 is sealed and fitted around the outer periphery of the cable outlet 21. The wrist also includes a rolling bearing 4, which is an existing component. The rolling bearing 4 is embedded in the mounting hole 11 and fitted around the outer periphery of the cable outlet 21. The oil seal ring 3 is located axially between the rolling bearing 4 and the retaining edge 12. The oil seal ring 3 includes an outer ring 31 and an inner ring 32. The inner ring 32 is fitted around the outer periphery of the cable outlet 21. An annular inner liner 5 is embedded on the outer periphery of the inner ring 32. The inner liner 5 is a metal part and is arranged coaxially with the oil seal ring 3. The inner edge of the inner ring 32 has an annular protrusion 31. The protrusion 31 corresponds to the position of the inner liner 5 along the radial direction of the oil seal ring 3. The protrusion 31 is fitted around the outer periphery of the cable outlet 21.
[0023] The oil seal ring 3 is axially confined between the rolling bearing 4 and the retaining edge 12 to ensure axial stability and prevent dislocation. At the same time, the open side of the oil seal ring 3 faces the wrist housing 2 and communicates with the outside, improving its resistance to deformation and maintaining good stability of the sealing effect.
[0024] The specific embodiments described herein are merely illustrative examples illustrating the spirit of this utility model. Those skilled in the art to which this utility model pertains may make various modifications or additions to the described specific embodiments or use similar methods to replace them, without departing from the spirit of this utility model or exceeding the scope defined by the appended claims.
Claims
1. A sealing structure for a robot wrist, the wrist comprising a housing (1) and a wrist shell (2), the housing (1) having a mounting hole (11), the sealing structure comprising an oil seal ring (3) with a U-shaped cross-section, characterized in that, The inner edge of the mounting hole (11) has an annular retaining edge (12). The oil seal ring (3) is embedded in the mounting hole (11) and the outer edge of the oil seal ring (3) is sealed against the inner edge of the mounting hole (11). The open side of the oil seal ring (3) is set along the axial direction of the mounting hole (11) toward the side where the wrist housing (2) is located and is limited against the retaining edge (12). The outer side of the wrist housing (2) has an annular cable outlet tube (21). The cable outlet tube (21) is rotatably inserted into the mounting hole (11) and the oil seal ring (3) is sleeved on the outer periphery of the cable outlet tube (21).
2. The sealing structure of the robot wrist according to claim 1, characterized in that, The wrist also includes a rolling bearing (4), which is embedded in the mounting hole (11) and sleeved on the outer periphery of the cable outlet (21). The oil seal ring (3) is located axially between the rolling bearing (4) and the retaining edge (12).
3. The sealing structure of the robot wrist according to claim 1 or 2, characterized in that, The oil seal ring (3) includes an outer ring (31) and an inner ring (32) that are both annular and coaxially arranged. The inner ring (32) is sleeved on the outer periphery of the cable outlet tube (21). The outer periphery of the inner ring (32) is fitted with an inner liner (5) that is annular and coaxially arranged with the oil seal ring (3). The inner liner (5) is made of a rigid material.
4. The sealing structure of the robot wrist according to claim 3, characterized in that, The inner edge of the inner ring (32) has an annular protrusion (321), which is located along the radial direction of the oil seal ring (3) and corresponds to the position of the inner liner (5). The protrusion (31) is sleeved on the outer periphery of the cable outlet tube (21).
5. The sealing structure of the robot wrist according to claim 1 or 2, characterized in that, The inner diameter of the retaining edge (12) is larger than the inner diameter of the oil seal ring (3).