Sealing arrangement for use in robot joint

A sealing arrangement for application in a robot joint. The sealing arrangement includes: a circular sealing assembly arranged between a swing and a base of the robot joint in a longitudinal direction, the circular sealing assembly defining a tubular cavity in a circumferential direction and having a gas inlet and a gas outlet; and an air channel coupled to the gas inlet and operable to continuously conduct pressured air flow into the cavity to maintain an air pressure inside the cavity above an air pressure outside the cavity, and thereby a high-speed airflow out of the gas outlet.

FIELD

Embodiments of present disclosure generally relates to a mechanical apparatus, and more particularly, to a sealing arrangement for use in a robot joint.

BACKGROUND

Robots, especially industrial robots (also called robot arms) have been widely utilized to aid manufacturers, for example, improve productivity, product quality and worker safety in various application fields. Industrial robots have various axis configurations. The vast majority of articulated robots normally enable multiple degrees (for example, four to six degrees) of freedom depending on the designed number of axis. In general, robots with more axes allow for greater flexibility and can perform a wider variety of applications than robots with fewer axes.

Axis1of an industry robot is a robot joint between the robot base and the swing. This axis allows the robot to rotate and sweep over a wide range to cover the area on either side of the robot and even behind the robot. In some cases, this axis allows the robot to spin up to a full 180 degree range from the center point.

However, for most of the current industrial robots, there is usually a gap existing in a region of Axis1between the base and the swing. In this case, pollutions/contaminants from the ambient, and otherwise, debris generated during the operation of the industry robot might cause issues and directly impact the performance of industrial robots. For example, the produced metal debris will be splashed around, or some liquid pollution might flow into the internal space of Axis1when the robot is operating in humid ambient. Once the infiltration of contaminants occurs, the internal structure of Axis1might be damaged, which will inevitably deteriorate the performance of the Axis1and thus the overall performance of the robot.

SUMMARY

In first aspect, a sealing arrangement for use in a robot joint is provided. The sealing arrangement comprises: a circular sealing assembly arranged between a swing and a base of the robot joint in a longitudinal direction, the circular sealing assembly defining a tubular cavity in a circumferential direction and having a gas inlet and a gas outlet; and an air channel coupled to the gas inlet and operable to conduct pressured air flow into the cavity to maintain an air pressure inside the cavity above an air pressure outside the cavity, and thereby a high-speed airflow out of the gas outlet.

Such sealing arrangement can rely on its circular sealing assembly to effectively isolate the internal space of Axis1from especially the external solid contaminants. Further, with such continuously directed higher-pressure air flow into the cavity, a relative high-speed airflow out of the gas outlet can be achieved. In such a way, the liquid pollutions/contaminants can be stopped outside the cavity. In this way, a more reliable protection of the internal structure of Axis1can be achieved.

In some embodiments, the circular sealing assembling comprises: a sealing ring forming a first side wall and a top wall of the cavity, wherein the first side wall is oriented in the longitudinal direction and the top wall is fixed to the swing and oriented in a horizontal direction that is substantially perpendicular to the longitudinal direction.

In some embodiments, the circular sealing assembling further comprises: a base ring coaxially arranged with the sealing ring and forming a second side wall of the cavity, wherein the second side wall is oriented opposite to the first side wall. Such vertically oriented base ring (or the second side wall of the cavity), as the outmost barrier/blocking component, can effectively reduce the risk of the solid contaminants entering into the internal space of Axis1structure. In some embodiments, the gas outlet is defined by the base ring together with the sealing ring, and thus the size of the gas outlet can be properly designed and tuned as needed.

In some embodiments, the circular sealing assembling further comprises: a radial seal arranged coaxially with the sealing ring and forming a bottom wall of the cavity, wherein the radial seal is positioned between a third side wall of the base and the first side wall in a radial direction.

In some embodiments, the radial seal is elastically arranged between the third side wall and the first side wall to abut against the third side wall and the first side wall in the radial direction.

In some embodiments, at least a portion of the radial seal is made of flexible material. The flexible material can help achieve a better sealing effect as it enables a sufficient contact with the counterpart surface.

In some embodiments, the flexible material is rubber.

In some embodiments, the sealing arrangement further comprising: an air tube connected to the air channel via a tube connector, wherein the air tube is operable to conduct the pressured air that is supplied from an external air source.

In some embodiments, the air pressure inside the cavity is in a range of 35 KPa to 55 KPa.

In some embodiments, the air pressure inside the cavity is approximately 45 KPa. Such properly tuned air pressure inside the cavity is beneficial, because it not only provides a stable and sufficient pressure to against the contaminant's infiltration, but also avoids a too high pressure at which the radial seal may lose its sealing ability

In second aspect, a robot joint is provided. The robot joint comprises: a base; a swing coupled to the base; and the sealing arrangement according to the first aspect of present disclosure.

It would be apparent through the following discussions that by using such sealing arrangement along with a continuously provided high air pressure inside the cavity of the sealing arrangement according to various embodiments of the present disclosure, the infiltration of solid and liquid pollutions or contaminants can be effectively avoided, and thereby a more reliable robot joint protection for Axis1can be achieved. Furthermore, such sealing arrangement according to various embodiments of the present disclosure has a simply structure/design, which enables a simple and straightforward manufacture/assembly process with a low cost.

Throughout the drawings, the same or similar reference symbols are used to indicate the same or similar elements.

DETAILED DESCRIPTION OF EMBODIMENTS

Principles of the present disclosure will now be described with reference to several example embodiments shown in the drawings. Though example embodiments of the present disclosure are illustrated in the drawings, it is to be understood that the embodiments are described only to facilitate those skilled in the art in better understanding and thereby achieving the present disclosure, rather than to limit the scope of the disclosure in any manner.

FIG. 1illustrates a general view of an industrial robot1000according to an embodiment of the present disclosure. Such industrial robot as shown inFIG. 1may be used as a grinding/polishing machine to handle surface grinding and polishing process. For instance, such industrial robot may be used for grinding/polishing the case of a cellphone. In a standard position as illustrated inFIG. 1, the base1is fixed on the ground, and the swing2that is arranged on top of the base1could rotate around the Axis1which is defined as a robot joint between a base1and a swing2, so that the swing2could sweep within a large operation area. The industrial robot1000may also be adapted to be used in an upside down orientation as shown inFIG. 2, depending on the specific requirements and operating conditions.

As discussed above, the debris (such as metal debris) produced during the grinding process might be splashed around in an uncontrolled way and thereby increasing the risk of the infiltration of debris into the gap between the base1and the swing2. In particular, when the robot is used in humid environments, such as wet grinding environment, cooling water is normally introduced in order to cool down the heat produced during the grinding process. In this case, even some blocking structures (for example, the wall of a base ring) may be designed and arranged to block the splashed solid debris, the slurry-like mixture produced from the cooling water and the debris may still be able to flow into the internal structure of Axis1due to the liquid surface tension. Liquid surface tension helps the liquid climb over the wall to arrive at the internal space of the Axis1structures, such as sealing structure, drive train structure, electrical parts and cables, which will damage the internal Axis1structure and thereby deteriorate the overall performance of the robot.

FIG. 3shows a detailed side view of the sealing arrangement100for use in a robot joint200as illustrated inFIG. 1. The sealing arrangement100generally includes a circular sealing assembly110(with its cross section being labeled by a dashed box) and an air channel1acoupled to the sealing assembly110. As shown inFIG. 3, the circular sealing assembly110is arranged between the swing2and the base1of the robot joint200in a longitudinal direction Y. In other words, the circular sealing assembly110is arranged surrounding the Axis1structure for sealing the gap existing between the swing2and the base1of the robot joint200. The sealing arrangement100as shown inFIG. 3can rely on its walls to effectively isolate the internal space of Axis1from the external solid contaminants.

Still in reference toFIG. 3, the circular sealing assembly110defines a tubular cavity120in a circumferential direction C and has a gas inlet111and a gas outlet112connected with the cavity120. The air channel1ais coupled to the gas inlet111and operable to continuously conduct pressured air flow into the cavity120to maintain an air pressure inside the cavity120above an air pressure outside the cavity120, and thereby a high-speed airflow coming out of the gas outlet. The higher air pressure inside the cavity120along with the high-speed air flow coming out of the gas outlet112helps further improve the sealing effect, because the pressured air coming out of the cavity120through the gas outlet112can further stop the liquid contaminant, such as slurry-like mixture, infiltrating into the cavity and the internal space of Axis1structure.

In some embodiments, the gas outlet112has a relative small feature size, for example, approximately 1 mm. Such small feature size, on one hand, is beneficial to keep a relatively strong air flow coming out of the gas outlet112, and on the other hand, will prevent the contaminants from infiltrating into the internal space of the cavity120and thus into the internal space of the robot joint200. It is to be understood that althoughFIG. 3shows a vertically oriented gas outlet112, the scope of the present disclosure is not limited to the shape or the orientation of the gas outlet112. Those skilled in the art would have a motivation to modify the shape or the orientation of gas outlet112according to the requirements.

FIG. 4shows an exploded perspective view of the sealing arrangement100for use in a robot joint200. As shown, in this embodiment, the circular sealing assembling110includes a sealing ring9. The sealing ring9forms a first side wall901and a top wall902of the cavity120. As illustrated inFIG. 4, the sealing ring9has a substantially inverted “L” shaped cross section. The first side wall901is oriented in the longitudinal direction Y and the top wall902is to be fixed to the swing2and oriented in a horizontal direction X that is substantially perpendicular to the longitudinal direction Y.

In some embodiments, the sealing ring9is fixed to the swing2via fixing means. For example, as shown inFIG. 4, the sealing ring9can be fixed to the swing2via at least one screw11. In some embodiments, an intermediate part, such as gasket10, is arranged between an end surface of the swing2and the sealing ring9in order to provide additional sealing between the two components. The scope of the present disclosure is not limited by the type of fixing/connecting mechanism between the sealing ring9and the swing2. Any suitable fixing/connecting mechanisms, such as a clip assembly, a magnet assembly, and an adhesive assembly that can achieve same or similar sealing effect are possible as well.

In some embodiments, the circular sealing assembling110may further include a base ring8. The base ring8is coaxially arranged with the sealing ring9and forms a second side wall801of the cavity120. The second side wall801is oriented opposite to the first side wall901. In other words, the second side wall801is also substantially oriented in the longitudinal Y direction. In some embodiments, the second side wall801is fixed at the top opening of the base1via interference fit. Of course, other securing mechanisms of the base ring8onto the top opening of the base1are also possible. Such vertically oriented base ring8(or the second side wall801of the cavity120) as shown inFIG. 3 or 4functions as the outmost barrier/blocking component which can effectively stop the solid contaminants to enter the internal space of Axis1structure.

Alternatively, or in addition, in some embodiments, the circular sealing assembling110further includes a radial seal7. The radial seal7is also arranged coaxially with the sealing ring9and forming a bottom wall701of the cavity120. As shown inFIG. 4, the radial seal7may be positioned between a third side wall101of the base1and the first side wall901in a radial direction R. In such embodiment, the gas inlet111is defined by the radial seal7and the base ring8, and the gas outlet112is defined by the sealing ring9and the base ring8. In this way, the size of gas inlet111and gas outlet112can both be properly designed and tuned.

In some embodiments, the radial seal7is elastically arranged between the third side wall101and the first side wall901to abut against the third side wall101and the first side wall901in the radial direction R. For example, the radial seal7may have an inverted “V” shaped cross section (or the so-called V-shaped sealing ring), and at least a portion of the radial seal7is made of flexible material such as rubber. The V-shaped sealing ring7can help achieve a better sealing effect as it enables a sufficient contact with the counterpart surface and the compressed amount is tunable via the angle of the V-shaped cross section.

The sealing arrangement100may further include an air tube5which is connected to the air channel1avia a tube connector6. The air tube5is operable to conduct the pressured air that is supplied from an external air source as shown inFIG. 5into the cavity20. One end of the tube connector6is shaped to fit with the channel1aand the other end of the tube connector6is shaped to receive the tube5, so that the connector6can be detachably connected with both the channel1aand the tube5.

Returning toFIG. 3, in some embodiments, the channel1ais built as part of the top wall of the base1, which may improve the integrity of the whole sealing arrangement100and meanwhile saves the internal space for accommodating the channel1a. It is to be understood that the example described with reference toFIG. 3is only for illustration, without suggesting any limitations as to the scope of the present disclosure. The channel1awith any other suitable shape, dimension, or orientation can be utilized in the sealing arrangement100.

In some embodiments, the air pressure inside the cavity120can be in a relatively broad range of 35 KPa to 55 KPa. However, in an ideal case, the air pressure inside the cavity120is properly tuned to approximately 45 KPa. Such properly tuned air pressure inside the cavity120is beneficial, because it not only provides a stable and sufficient pressure to against the contaminant's infiltration, but also avoids a too high pressure at which the radial seal7may lose its sealing ability.

FIG. 6is a flowchart of a method600for manufacturing a sealing arrangement100according to embodiments of the present disclosure.FIG. 7shows an exploded view of the sealing arrangement for use in a robot joint in an unassembled state, according to embodiments of the present disclosure.

In accordance with embodiments of the present disclosure, the sealing arrangement100as described above can be manufactured in a simple and straightforward way. Actions of the method600will now be described with reference toFIGS. 6 and 7.

At block602, the circular sealing assembly110defining a tubular cavity120in a circumferential direction C and having a gas inlet111and a gas outlet112is arranged between the swing2and the base1of the robot joint200in a longitudinal direction Y. In some embodiments, arranging the circular sealing assembly110may include arranging the base ring8via interference fit to an upper opening of the base1to define a second side wall801of the cavity120; arranging the radial seal7coaxially with the base ring8to define the bottom wall701of the cavity120; and arranging the sealing ring9pre-fixed to the swing2to define the first side wall901and the top wall902of the cavity120, respectively.

At block604, an air channel1ais coupled to the gas inlet111to conduct high pressured air into the cavity120. In some embodiments, coupling the air channel to the gas inlet to conduct pressured air includes: connecting one end of an air tube5to the air channel1avia a tube connector6; connecting the other end of the air tube5to an external air source; and supplying the pressured air from the external air source to the cavity120. Optionally, method600may further includes fixing a base cover3with some screws4in order isolate the external air source from the air tube5and therefore the internal space of the base1.

In an example, the ideal inside pressure is set to be 45 KPa. In order to achieve such an ideal inside pressure, the air pressure that actually needs to be pumped into the gas inlet111is in a range of 50 KPa to 55 KPa considering the air leakage from gas outlet112. In this example, the upper limit of 55 KPa indicates an air pressure level beyond which the radial seal7may lose its sealing ability, and the lower level of 50 KPa indicates an air pressure at which the sealing arrangement100may not be able to provide stable and sufficient air flow to against the contaminant infiltration.

It should be appreciated that the above detailed embodiments of the present disclosure are only to exemplify or explain principles of the present disclosure and not to limit the present disclosure. Therefore, any modifications, equivalent alternatives and improvement, etc. without departing from the spirit and scope of the present disclosure shall be included in the scope of protection of the present disclosure. Meanwhile, appended claims of the present disclosure aim to cover all the variations and modifications falling under the scope and boundary of the claims or equivalents of the scope and boundary.