WO2022193061A1

WO2022193061A1 - Sealing component, gearbox and robot

Info

Publication number: WO2022193061A1
Application number: PCT/CN2021/080764
Authority: WO
Inventors: Gongyao Ma; Qianhu Zhang; Xinguo FU
Original assignee: Abb Schweiz Ag
Priority date: 2021-03-15
Filing date: 2021-03-15
Publication date: 2022-09-22
Also published as: CN116964356A

Abstract

Embodiments of the present disclosure provide a sealing component, a gearbox and a robot. The sealing component comprises a base ring arranged in an internal chamber of the gearbox adjacent to a bearing for supporting a main shaft of the gearbox, the base ring coupled to the main shaft to rotate with the main shaft; and at least one stirring member radially protruding from a periphery of the base ring and each comprising a pair of inclined stirring surfaces inclined in opposite directions, so that a circumferential distance between the pair of inclined stirring surfaces is gradually reduced in an axial direction away from the bearing. With the pair of inclined stirring surfaces, during the operation of the gearbox, the lubricant trapped between the end part and the main shaft can be pushed out to re -participate in the lubricating and cooling of other components, thereby increasing the utilization rate of the lubricant. In addition, the assembling complexity of the gearbox can be reduced due to the absence of the dynamic seal. Furthermore, the pressure in the internal chamber may be reduced and thus the sealing performance of the gearbox may be further improved.

Description

SEALING COMPONENT, GEARBOX AND ROBOT

FIELD

Embodiments of the present disclosure generally relate to a gearbox of a robot, and more specifically, to a sealing component for a gearbox.

BACKGROUND

Robots are widely-used automation mechanisms that increase operational efficiency and accuracy. A robot typically comprises robot arm links and joints. The robot arm link can be driven to rotate or move by a motor arranged in the joint or a base. To meet the reduction ratio requirements, a gearbox or a reducer needs to be arranged between the motor and the robot arm links to be driven. The gearbox is a device that uses gears and gear trains to provide speed and torque conversions from a rotating power source to another device.

Lubricant such as oil and/or grease is usually provided in the gearbox to provide lubrication for the gears and other components. Besides the lubrication function for the individual elements to substantially reduce friction, lubricant in the gearbox can also cool the heated subassemblies as well as mitigate and attenuate gear strokes. In addition, it reduces vibration, protects against corrosion, and keeps everything clean. Lubricant is usually located in an internal chamber of the gearbox to provide lubrication to the various components around the internal chamber. Lubricant usually fills roughly half of the internal chamber.

SUMMARY

Embodiments of the present disclosure provide a sealing component for a gearbox, an associated gearbox and a robot.

In a first aspect, a sealing component for a gearbox is provided. The sealing component comprises a base ring arranged in an internal chamber of the gearbox adjacent to a bearing for supporting a main shaft of the gearbox, the base ring coupled to the main shaft to rotate with the main shaft; and at least one stirring member radially protruding from a periphery of the base ring and each comprising a pair of inclined stirring surfaces inclined in opposite directions, so that a circumferential distance between the pair of inclined stirring surfaces is gradually reduced in an axial direction away from the bearing.

With the pair of inclined stirring surfaces, during the operation of the gearbox, the lubricant trapped between the end part and the main shaft can be pushed out to re-participate in the lubricating and cooling of other components, thereby increasing the utilization rate of the lubricant. In addition, the assembling complexity of the gearbox can be reduced due to the absence of the dynamic seal. Furthermore, the pressure in the internal chamber may be reduced and thus the sealing performance of the gearbox may be further improved.

In some embodiments, a radially protruding distance of the at least one stirring member is below a radial thickness of the bearing. This arrangement can ensure the stirring effect while reducing the friction between the stirring member and the end part.

In some embodiments, absolute values of inclination angles of the pair of inclined stirring surfaces relative to a plane of an axis of the main shaft are equal. In this way, the same stirring effect can be obtained regardless of whether the main shaft rotates forward or backward.

In some embodiments, each of the at least one stirring member comprises a pair of stirring plates; and wherein the pair of inclined stirring surfaces are outer surfaces of the pair of stirring plates away from each other, respectively. This arrangement can simplify the manufacturing of the stirring member.

In some embodiments, each of the at least one stirring members comprises a stirring portion; and a reinforced portion arranged between the stirring portion and the base ring and having a circumferential thickness that gradually increases from the stirring portion to the base ring. On the one hand, with the reinforced portion, the strength of the stirring member may be improved. On the other hand, the gradually thicker structure of the stirring member towards the base ring pushes the lubricant away from the bearing while also pushing it radially outward, thereby further enhancing the stirring effect and thus the sealing performance of the gearbox.

In some embodiments, the at least one stirring member comprises a plurality of stirring members evenly arranged on the periphery of the base ring. As a result, the stirring effect with the plurality of stirring members may be further improved.

In some embodiments, the body is embedded with a metal ring. This arrangement can enhance the strength of the stirring member.

In some embodiments, the sealing component is adapted to be radially arranged between the main shaft and an end part for the gearbox. This arrangement makes the arrangement of the pressure relief component more flexible and more applicable.

In a second aspect of the present disclosure, a gearbox is provided. The gearbox comprises a main shaft and a sealing component as mentioned in the first aspect coupled to the main shaft to rotate with the main shaft.

In some embodiments, the gearbox further comprises a housing at least partially surrounding an internal chamber to receive the main shaft and lubricant; an end part arranged at an end of the housing to close the internal chamber; and a bearing arranged to support a main shaft of the gearbox and allow a relative movement between the main shaft and the end part, wherein the sealing component is arranged in the internal chamber adjacent to the bearing to stir the lubricant away from the gear and out of a gap between the main shaft and the end part.

In some embodiments, the end part is an input or output flange for the gearbox or at least a part of a robot arm coupled to the gearbox. This arrangement makes the arrangement of the sealing component more flexible and more applicable.

In a third aspect of the present disclosure, a robot is provided. The robot comprises at least one robot arm coupled to the gearbox as mentioned in the above second aspect.

It is to be understood that the Summary is not intended to identify key or essential features of embodiments of the present disclosure, nor is it intended to be used to limit the scope of the present disclosure. Other features of the present disclosure will become easily comprehensible through the description below.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objectives, features and advantages of the present disclosure will become more apparent through more detailed depictions of example embodiments of the present disclosure in conjunction with the accompanying drawings, wherein in the example embodiments of the present disclosure, same reference numerals usually represent the same components.

FIG. 1 shows a side sectional view of a gearbox in the prior art;

FIG. 2 shows a partial perspective view of a gearbox according to embodiments of the present disclosure;

FIG. 3 shows a side sectional view of a gearbox according to embodiments of the present disclosure;

FIGs. 4 and 5 show perspective views of a sealing component according to embodiments of the present disclosure; and

FIG. 6 shows a side view of a sealing component according to embodiments of the present disclosure.

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

DETAILED DESCRIPTION

The present disclosure will now be discussed with reference to several example embodiments. It is to be understood these embodiments are discussed only for the purpose of enabling those skilled persons in the art to better understand and thus implement the present disclosure, rather than suggesting any limitations on the scope of the subject matter.

As used herein, the term “comprises” and its variants are to be read as open terms that mean “comprises, but is not limited to. ” The term “based on” is to be read as “based at least in part on. ” The term “one embodiment” and “an embodiment” are to be read as “at least one embodiment. ” The term “another embodiment” is to be read as “at least one other embodiment. ” The terms “first, ” “second, ” and the like may refer to different or same objects. Other definitions, explicit and implicit, may be comprised below. A definition of a term is consistent throughout the description unless the context clearly indicates otherwise.

FIG. 1 shows a side sectional view of a gearbox in the prior art. As shown in FIG. 1, a gearbox typically comprises a main shaft 204’ and a housing for receiving gears for transmission, bearings 203’ for supporting the main shaft 204’ and allowing relative movement between the main shaft 204’ and the end part. The housing is closed by end parts such as end flanges or parts of a robot arm coupled to the gearbox 200’. The housing and end parts enclose an internal chamber 202’ for containing lubricant to lubricate various parts received in the housing.

Lubricant used for the gearbox is usually located in an internal chamber inside the gearbox and occupies roughly half of the volume of the internal chamber, while the other half is occupied by air. The internal chamber is typically at least partially surrounded by a housing for receiving at least a part of a main shaft, gears and bearings. There are end parts arranged at both ends of the housing to close the internal chamber. Each end part may be an end flange or a part of a robot arm coupled to the gearbox. During the operation of a gearbox, due to factors such as friction between the various components, the temperature of the lubricant and the components will increase, which will increase the volume of the lubricant and air, resulting in an increased pressure in the internal chamber.

The increased pressure will deteriorate the sealing system of the gearbox used for the internal chamber, which typically comprises dynamic seals 205’ and static seals 206’. Dynamic seals 205’ mean seals arranged between parts, such as the main shaft 204’ and the end part 201’, that have relative motions, and static seals 206’ mean seals arranged between parts without relative motions. Under normal circumstances, the pressure that the sealing system can withstand is a predetermined value or range. When the pressure of the internal chamber is greater than this value or range, the sealing system may fail, causing lubricant to leak out and thus causing a series of serious problems.

Furthermore, during assembling of the main shaft 204’ and the bearing 203’ to the end part 201’, in order to provide guidance for ease of assembly, the inwardly facing end 2011’ of the end part 201’ is usually axially elongated. This causes a gap to be formed between the inwardly facing end 2011’ of the end part 201’ and the main shaft 204’ after the assembly is completed. This gap is a part of the internal chamber 202’. During the operation of the gearbox, especially when the gearbox 200’ is in the vertical orientation shown in FIG. 1, the gap is likely to retain lubricant such as oil and grease. On the one hand, the lubricant trapped here is usually difficult to be reused, which leads to the reduction of lubricant in other parts and thus deteriorates the lubrication and cooling effect of the gearbox. On the other hand, the lubricant accumulated here is easier to escape when the internal chamber 202’ is under high pressure, causing sealing problems.

In order to at least partially address the above and other potential problems, embodiments of the present disclosure provide a sealing component 100 for a gearbox 200 to improve sealing performance of the gearbox 200 by preventing the lubricant from being trapped in the gap between the end part 204 and the main shaft 201 and by allowing high-pressure gas within the internal chamber 202 to escape. Now some example embodiments will be described with reference to FIGs. 2-6.

FIGs. 2 and 3 respectively show a partial perspective view and a side sectional view of a gearbox 200 with a sealing component 100 according to embodiments of the present disclosure. As shown in FIGs. 2 and 3, the sealing component 100 generally comprises a base ring 101 and at least one stirring member 102. The base ring 101 is arranged in the internal chamber 202 adjacent to the bearing 203 and coupled to the main shaft 201 to rotate with the main shaft 201. That is, the base ring 101 is arranged between the main shaft 201 and an inwardly facing end of the end part 204. The bearing 203 is used to support the main shaft 201 and allow the relative movement between the mian shaft 201 and the end part 204. The end part 204 for the gearbox 200 is a part close to the internal chamber 202 and may be an end flange or a part of a robot arm coupled to the gearbox 200. In the following, embodiments of the present disclosure will be described mainly by taking the end part 204 as an end flange as an example. It is to be understood that embodiments where the end part 204 comprises other components such as robot arms are similar, and will not be described separately in the following.

In some embodiments, the base ring 101 may be a ring made of elastic material such as rubber or silicon, so that the base ring 101 can be tightly sleeved on the main shaft 201 by means of a restoring force thereof. In this way, the base ring 101 can be easily mounted on the main shaft 201.

It is to be understood that the above embodiments where the base ring 101 is a ring made of elastic material are merely illustrative, without suggesting any limitation as to the scope of the present application. Any other suitable arrangement is also possible. For example, in some embodiments, to improve the strength of the base ring 101, the base ring 101 may be embedded with a metal ring. For example, the metal ring may be embedded in the base ring 101 when the base ring 101 is manufactured by molding, etc.

The at least one stirring member 102 radially protrudes from a periphery of the base ring 101. In some embodiments, there may be a plurality of stirring members 102 evenly arranged on the periphery of the base ring 101 in a circumferential direction. Each stirring member 102 may comprise a pair of inclined stirring surfaces 1022 inclined in opposite directions relative to a plane of an axis of the main shaft 201. The stirring surfaces 1022 according to embodiments of the present disclosure mean surfaces that actually participate in stirring, that is, surfaces that can contact lubricant and push the lubricant to move. The inclined stirring surfaces 1022 are arranged so that a circumferential distance between the pair of inclined stirring surfaces 1022 is gradually reduced in an axial direction away from the bearing 203, as shown in FIGs. 2 and 3. In this way, when viewed in the radial direction towards the axis of the main shaft 201, these two surfaces basically correspond to two bevel edges of a triangle or a trapezoid in some cases, and the vertex of the triangle or the short side of the trapezoid is away from the bearing 203.

During the operation of a gearbox 200, the base ring 101 and the stirring member 102 rotate with the main shaft 201. Due to the inclined stirring surfaces 1022, the lubricant trapped in the gap between the main shaft 201 and the end part 204 and adjacent to the bearing 203 may be pushed out of the gap and away from the bearing 203. The lubricant that is pushed out will re-participate in the lubricating and cooling of other components, thereby increasing the utilization rate of the lubricant. In addition, because the stirring member 102 is evenly distributed on the base ring 101, there will be enough lubricant in contact with the bearing 203 to lubricate and cool the bearing 203 in the gap.

Furthermore, with the stirring member 102 and the base ring 101, since a large amount of lubricant does not accumulate in the gap between the main shaft 201 and the end part 204, there is no need for a dynamic seal, e.g., the dynamic seal 205’ as shown in FIG. 1, arranged at the same end of the main shaft 201, and there will be no leakage of lubricant at this position. In this way, the assembling complexity of the gearbox 200 can be reduced due to the absence of the dynamic seal.

Furthermore, without the dynamic seal at the same end of the main shaft 201, the high-pressure gas within the internal chamber 202 of the gearbox 200 may escape through some tiny gaps, e.g., in the bearing 203 or the like without causing lubricant leakage. As a result, the pressure in the internal chamber 202 may be maintained at an appropriate level and thus the sealing performance of the gearbox 200 may be further improved.

In some embodiments, the base ring 101 may axially extend a predetermined distance. That is, the base ring 101 may have an axial width equal to the predetermined distance in an axial direction. Correspondingly, each of the inclined stirring surfaces 1022 may extend along at least a half of the width of the base ring 101 in the axial direction. In some embodiments, to obtain a better stirring effect, each of the inclined stirring surfaces 1022 may extend along the full width of the base ring 101 in the axial direction.

In some embodiments, the pair of inclined stirring surfaces 1022 may intersect. For example, in some embodiments, the pair of inclined stirring surfaces 1022 may be two side surfaces of a triangular prism protruding radially from the base ring 101. That is, in some embodiments, the stirring member 102 may be a solid structure of the triangular prism. In some alternative embodiments, the stirring member 102 may also be a hollow structure of the triangular prism. In this case, besides the pair of inclined stirring surfaces 1022, the stirring member 102 may also comprise a bottom surface intersecting with the pair of inclined stirring surfaces 1022 and extending in the circumferential direction.

In some embodiments, the stirring member 102 may only comprise a pair of stirring plates 1021 radially protruding from the base ring 101, without the bottom surface as mentioned above, as shown in FIG. 2. In this case, the pair of the inclined stirring surfaces 1022 are outer surfaces of the pair of the stirring plates 1021 away from each other, respectively. In this way, the stirring member 102 may be formed easily and thus simplify the manufacturing of the sealing component 100.

It is to be understood that the above embodiments where the pair of inclined stirring surfaces 1022 intersecting with each other are merely illustrative, without suggesting any limitation as to the scope of the present disclosure. Any other suitable arrangement or structure is also possible. For example, in some alternative embodiments, the pair of inclined stirring surfaces 1022 may not intersect with each other. For example, the pair of inclined stirring surfaces 1022 may intersect with an upper surface at ends thereof away from the bearing 203. In this case, when viewed in the radial direction to the axis of the main shaft 201, these two surfaces basically correspond to the two bevel edges of a trapezoid, and there may be a short side of the trapezoid corresponding to the upper surface and arranged between the pair of the inclined stirring surfaces 1022 at the end away from the bearing 203.

To obtain a better effect of pushing lubricant out of the gap between the main shaft 201 and the end part 204, in some embodiments, a radially protruding distance of the stirring member 102 may be below, i.e., equal to or smaller than a radial thickness of the bearing 203, as shown in FIG. 3. In this way, together with the base ring 101, the stirring member 102 extends radially from the main shaft 201 almost to an inner side of the end part 204, and does not touch or just touch the inner side of the end part 204. In this way, a better stirring effect can be obtained without generating friction between the end part 204 and the stirring member 102.

In some embodiments, absolute values of inclination angles of the pair of inclined stirring surfaces 1022 relative to a plane of the axis of the main shaft 201 may be equal. For example, in some embodiments, one of the pair of inclined stirring surfaces 1022 may be inclined by 45° with respect to the plane of the axis of the main shaft 201, while the other inclined surface is inclined by -45°. In this way, the same stirring effect can be obtained regardless of whether the main shaft 201 rotates forward or backward.

It is to be understood that the above embodiments where the inclined stirring surfaces 1022 are inclined by 45° and -45° are merely illustrative, without suggesting any limitation as to the scope of the present disclosure. Depending on the viscosity of the lubricant used and the required stirring effect, the inclination angles of the inclined stirring surfaces 1022 may also be different and may be any predetermined value, such as 30° or 60°.

In some embodiments, the stirring member 102 and the base ring 101 may be integrally made of suitable material such as rubber or silicon. In this way, the sealing component 100 may be manufactured in a cost-efficient way.

FIGs. 4-6 show perspective and side views of the sealing component 100 according to some example embodiments of the present disclosure. As can be seen from FIGs. 4-6, to further improve the strength of the sealing component 100, the stirring member 102 may comprise a stirring portion 1024 and a reinforced portion 1025. The reinforced portion 1025 is arranged between the stirring portion 1024 and the base ring 101 and has a circumferential thickness that gradually increases from the stirring portion 1024 to the base ring 101. In addition, a smooth transition is provided at the junction of the reinforced portion 1025 and the base ring 101, thereby making the sealing component 100 easier to manufacture and further improving the stirring effect of the stirring member 102.

On the one hand, with the reinforced portion 1025, the strength of the stirring member 102 may be improved. In this way, the high-speed flow of lubricant relative to the stirring member 102 cannot deform the stirring member 102 so as to ensure the stirring effect. On the other hand, with the gradually thicker structure towards the base ring 101, the stirring member 102 can push the lubricant away from the bearing 203 while also pushing it radially outward, thereby further enhancing the stirring effect and thus the sealing performance of the gearbox 200.

According to other aspects of the present disclosure, a gearbox 200 comprising the sealing component 100 as mentioned above and a robot comprising the gearbox 200 are provided. The gearbox 200 further comprises a main shaft, a housing at least partially surrounding the internal chamber to receive the main shaft and lubricant. The sealing component 100 is adapted to be arranged in the internal chamber of the gearbox adjacent to a bearing, e.g., between the main shaft 201 and the end part 204 of the gearbox 200, to stir the lubricant away from the gear and out of a gap between the main shaft 201 and the end part 204. The end part 204 may be an end flange or a part of a robot arm coupled to the gearbox. The robot comprises at least one robot arm coupled to the gearbox 200 as mentioned above. With the sealing component 100 according to embodiments of the present disclosure, the sealing performance of the gearbox 200 can be significantly improved and thus prolong the service life of the gearbox 200 and the robot.

It should be appreciated that the above detailed embodiments of the present disclosure are only for exemplifying or explaining principles of the present disclosure and do not limit the present disclosure. Therefore, any modifications, equivalent alternatives and improvements, etc. without departing from the spirit and scope of the present disclosure shall be comprised 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.

Claims

A sealing component for a gearbox (200) , comprising:

a base ring (101) arranged in an internal chamber (202) of the gearbox (200) adjacent to a bearing (203) for supporting a main shaft (201) of the gearbox (200) , the base ring (101) coupled to the main shaft (201) to rotate with the main shaft (201) ; and

at least one stirring member (102) radially protruding from a periphery of the base ring (101) and each comprising a pair of inclined stirring surfaces (1022) inclined in opposite directions, so that a circumferential distance between the pair of inclined stirring surfaces (1022) is gradually reduced in an axial direction away from the bearing (203) .
The sealing component of claim 1, wherein a radially protruding distance of the at least one stirring member (102) is below a radial thickness of the bearing (203) .
The sealing component of claim 1, wherein absolute values of inclination angles of the pair of inclined stirring surfaces (1022) relative to a plane of an axis of the main shaft (201) are equal.
The sealing component of claim 1, wherein each of the at least one stirring member (102) comprises a pair of stirring plates (1021) ; and

wherein the pair of inclined stirring surfaces (1022) are outer surfaces of the pair of stirring plates (1021) away from each other, respectively.
The sealing component of claim 1, wherein each of the at least one stirring member (102) comprises:

a stirring portion (1024) ; and

a reinforced portion (1025) arranged between the stirring portion (1024) and the base ring (101) and having a circumferential thickness that gradually increases from the stirring portion (1024) to the base ring (101) .
The sealing component of claim 1, wherein the at least one stirring member (102) comprises a plurality of stirring members (102) evenly arranged on the periphery of the base ring (101) .
The sealing component of claim 1, wherein the body is embedded with a metal ring.
The sealing component of claim 1, wherein the sealing component is adapted to be radially arranged between the main shaft (201) and an end part (204) for the gearbox (200) .
A gearbox (200) , comprising:

a main shaft (201) ; and

a sealing component of any of claims 1-8 coupled to the main shaft (201) to rotate with the main shaft (201) .
The gearbox (200) of claim 9, further comprising:

a housing at least partially surrounding an internal chamber (202) to receive the main shaft (201) and lubricant;

an end part (204) arranged at an end of the housing to close the internal chamber (202) ; and

a bearing (203) arranged to support a main shaft (201) of the gearbox (200) and allow a relative movement between the main shaft (201) and the end part (204) ,

wherein the sealing component (100) is arranged in the internal chamber (202) adjacent to the bearing (203) to stir the lubricant away from the gear (203) and out of a gap between the main shaft (201) and the end part (204) .
The gearbox (200) of claim 9 or 10, wherein the end part (204) is an input or output flange for the gearbox (200) or at least a part of a robot arm coupled to the gearbox (200) .
A robot, comprising at least one robot arm coupled to a gearbox (200) of any of claims 9-11.