阅读说明：本技术 轴承及密封装置 (Bearing and sealing device ) 是由 刘鑫 吴丽娟 张建昌 秦傲然 李定 于 2021-01-18 设计创作，主要内容包括：本发明实施例提供一种轴承及密封装置,所述密封装置包括：骨架；密封部,整体呈环形结构,所述密封部包括弹性部和塑性部,所述弹性部固定于所述骨架,当将所述密封装置设置于轴承内圈和轴承外圈之间后,所述塑性部与轴承内圈形成接触密封,所述弹性部和所述塑性部相对固定,且在径向方向上至少部分所述塑性部设置于所述轴承内圈和所述弹性部之间,所述塑性部的材料的摩擦系数小于所述弹性部的材料的摩擦系数。本发明实施例提供的密封装置可以提高密封装置的密封效果,且延长密封装置的使用寿命。(The embodiment of the invention provides a bearing and a sealing device, wherein the sealing device comprises: a framework; the sealing part is wholly of an annular structure and comprises an elastic part and a plastic part, the elastic part is fixed on the framework, when the sealing device is arranged between the bearing inner ring and the bearing outer ring, the plastic part and the bearing inner ring form contact sealing, the elastic part and the plastic part are relatively fixed and at least partially arranged in the radial direction, the plastic part is arranged between the bearing inner ring and the elastic part, and the friction coefficient of the material of the plastic part is smaller than that of the material of the elastic part. The sealing device provided by the embodiment of the invention can improve the sealing effect of the sealing device and prolong the service life of the sealing device.)

1. A seal arrangement adapted to be disposed between a bearing inner race and a bearing outer race, the seal arrangement comprising:

a framework;

the sealing part is wholly of an annular structure and comprises an elastic part and a plastic part, the elastic part is fixed on the framework, when the sealing device is arranged between the bearing inner ring and the bearing outer ring, the plastic part and the bearing inner ring form contact sealing, the elastic part and the plastic part are relatively fixed and at least partially arranged in the radial direction, the plastic part is arranged between the bearing inner ring and the elastic part, and the friction coefficient of the material of the plastic part is smaller than that of the material of the elastic part.

2. The seal of claim 1, wherein said plastic portion is generally annular in configuration and includes a fixedly connected outer ring fixed end portion fixed to an axially outer end surface of said frame and an inner ring free end portion capable of bending in an axial direction of said seal when said seal is disposed between an inner race and an outer race of a bearing, said inner ring free end portion being disposed between said inner race and said elastic portion in a radial direction, said elastic portion being fixed relative to said inner ring free end portion.

3. The seal of claim 2, wherein the inner race free end defines an annular groove that opens toward the inner race when the inner race free end is disposed between the inner race and the outer race.

4. The sealing device of claim 2, further comprising:

the stop ring is fixed on the framework, and the stop ring and the framework are respectively arranged at the two axial ends of the plastic part.

5. The seal of claim 3, wherein the plastic portion further includes a thrust surface at an axially inner end of the plastic portion when the plastic portion forms a contact seal with the bearing inner race.

6. The seal of claim 5, wherein the thrust surfaces are evenly distributed along a circumference of the plastic portion and slope directions of adjacent thrust surfaces are symmetrical about a boundary line of adjacent thrust surfaces.

7. A sealing device according to any of claims 1 to 6, wherein the plastic part is made of polytetrafluoroethylene.

8. The sealing device of any of claims 2-6, wherein the plastic portion further comprises:

and the dustproof lip is fixed on the axial outer end face of the annular fixed end part, and when the inner ring free end part is arranged between the bearing inner ring and the bearing outer ring, the dustproof lip extends towards the direction which is axially deviated from the inner ring free end part and is radially close to the bearing inner ring.

9. The sealing device of any one of claims 1-6, further comprising:

and the spring is of an annular structure as a whole, is sleeved on the outer annular surface of the elastic part and is arranged on the cross section where the elastic part, the plastic part and the bearing inner ring exist simultaneously.

10. A bearing comprising an inner race, an outer race and a sealing arrangement as claimed in any of claims 1 to 9, the sealing arrangement being disposed between the inner and outer races.

Technical Field

The embodiment of the invention relates to the technical field of bearing sealing, in particular to a bearing and a sealing device.

Background

An articulated robot, also called an articulated arm robot or an articulated robot arm, is one of the most common forms of industrial robots in the industrial field today, and is suitable for mechanical automation operations in many industrial fields. The articulated arm bearing plays a decisive role in the load-bearing capacity, the dynamic behavior and the accuracy of the robot.

The knuckle arm bearing comprises an inner ring, an outer ring and a sealing ring arranged between the inner ring and the outer ring. The sealing ring is used for preventing grease leakage. Because the articulated arm of robot will realize repeatedly snatching and the rocking arm action of withdrawing, need often switch over the direction of rotation of bearing, easily produce the risk that lubricating grease leaked.

Therefore, the sealing performance of the articulated arm bearing is to be improved.

Disclosure of Invention

The technical problem solved by the embodiment of the invention is to improve the sealing performance of the bearing.

In order to solve the above problem, an embodiment of the present invention provides a bearing adapted to be disposed between a bearing inner ring and a bearing outer ring, where the sealing device includes:

a framework;

the sealing part is wholly of an annular structure and comprises an elastic part and a plastic part, the elastic part is fixed on the framework, when the sealing device is arranged between the bearing inner ring and the bearing outer ring, the plastic part and the bearing inner ring form contact sealing, the elastic part and the plastic part are relatively fixed and at least partially arranged in the radial direction, the plastic part is arranged between the bearing inner ring and the elastic part, and the friction coefficient of the material of the plastic part is smaller than that of the material of the elastic part.

Optionally, the plastic part is integrally of an annular structure and comprises an outer ring fixed end and an inner ring free end which are fixedly connected, the outer ring fixed end is fixed on the axial outer end face of the framework, when the sealing device is arranged between the bearing inner ring and the bearing outer ring, the inner ring free end can bend along the axial direction of the sealing device and is arranged between the bearing inner ring and the elastic part in the radial direction, and the elastic part and the inner ring free end are relatively fixed.

Optionally, the free end of the inner ring is provided with an annular groove, and when the free end of the inner ring is arranged between the bearing inner ring and the bearing outer ring, an opening of the annular groove faces the bearing inner ring.

Optionally, the sealing device further comprises:

the stop ring is fixed on the framework, and the stop ring and the framework are respectively arranged at the two axial ends of the plastic part.

Optionally, the plastic part further comprises a thrust surface located at an axially inner end of the plastic part when the plastic part forms a contact seal with the bearing inner race.

Optionally, the thrust surfaces are uniformly distributed along the circumferential direction of the plastic part, and the slope directions of the adjacent thrust surfaces are symmetrical with respect to the boundary line of the adjacent thrust surfaces.

Optionally, the plastic portion is made of polytetrafluoroethylene.

Optionally, the plastic part further comprises:

and the dustproof lip is fixed on the axial outer end face of the annular fixed end part, and when the inner ring free end part is arranged between the bearing inner ring and the bearing outer ring, the dustproof lip extends towards the direction which is axially deviated from the inner ring free end part and is radially close to the bearing inner ring.

Optionally, the sealing device further comprises:

and the spring is of an annular structure as a whole, is sleeved on the outer annular surface of the elastic part and is arranged on the cross section where the elastic part, the plastic part and the bearing inner ring exist simultaneously.

In order to solve the above problem, an embodiment of the present invention further provides a bearing, which includes a bearing inner ring, a bearing outer ring, and the sealing device, where the sealing device is disposed between the bearing inner ring and the bearing outer ring.

Compared with the prior art, the technical scheme of the embodiment of the invention has the following advantages:

in the sealing device provided by the embodiment of the invention, after the sealing device is arranged between the bearing inner ring and the bearing outer ring, the plastic part and the bearing inner ring form contact sealing, the elastic part and the plastic part are relatively fixed, and the plastic part is arranged between the bearing inner ring and the elastic part in the radial direction, so that in the working process of the bearing, the plastic part and the bearing inner ring generate relative rotation, because the friction coefficient of the material of the plastic part is smaller than that of the material of the elastic part, and the friction force between the plastic part and the bearing inner ring is smaller than that between the elastic part and the bearing inner ring, the surface of the plastic part, which is in contact with the bearing inner ring, is not easy to generate wrinkles, and therefore, even if the bearing suddenly changes the rotation direction, the grease cannot be timely changed along with the rotation direction, and the phenomenon that the grease moves along the axial direction due to the pumping action of the wrinkles is avoided, therefore, when the bearing inner ring changes the rotating direction suddenly, the grease leakage between the bearing inner ring and the plastic part can be improved, the sealing effect of the sealing device is improved, the friction force between the plastic part and the bearing inner ring is further reduced, and the service life of the sealing device can be prolonged.

In the alternative, the plastic part is of an annular structure integrally and comprises an outer ring fixed end part and an inner ring free end part which are fixedly connected, the outer ring fixed end part is fixed on the axial outer end face of the framework, after the sealing device is arranged between the bearing inner ring and the bearing outer ring, the inner ring free end part can bend along the axial direction of the sealing device and is arranged between the bearing inner ring and the elastic part in the radial direction, and the elastic part and the inner ring free end part are fixed relatively. Through being fixed in the skeleton with plasticity portion, improved the fastness, avoided plasticity portion along axial motion, guaranteed that plasticity portion terminal surface is parallel with the axial terminal surface of other parts (bearing inner race ) of bearing. After the sealing device is installed, the free end part of the inner ring can be bent along the axial direction of the sealing device and is arranged between the bearing inner ring and the elastic part in the radial direction, so that the contact area of the plastic part and the bearing inner ring can be increased, and a space is provided for the subsequent arrangement of an annular groove at the free end part of the inner ring.

Drawings

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced below, it is obvious that the drawings in the following description are only embodiments of the present application, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.

FIGS. 1 and 2 are schematic views of the sealing device interacting with the bearing inner race in different rotational directions;

FIG. 3 is a schematic structural diagram of a sealing device provided in an embodiment of the present invention;

FIG. 4 is another schematic structural view of a sealing device provided in accordance with an embodiment of the present invention;

FIG. 5 is a schematic view of the installation state of FIG. 4;

FIG. 6 is a schematic view of another embodiment of a sealing device according to the present invention;

fig. 7 is a schematic structural diagram of a bearing provided in an embodiment of the present invention.

Wherein: 1-sealing lip; 2-bearing inner race; 5-a sealing part; 10-an elastic portion; 20-a plastic portion; 210-outer ring fixed end; 220-inner ring free end; 200-an annular trench; 230-dust lip; 30-a framework; 40-a bearing outer ring; 50-bearing inner race; 60-thrust surface; 70-a stop ring; 80-spring.

Detailed Description

As is known from the background art, the sealing performance of the articulated arm bearing needs to be improved.

The reason for the poor sealing performance of the bearing is analyzed in conjunction with fig. 1-2.

Fig. 1 and 2 are schematic views of the interaction of the sealing device and the bearing inner ring in different rotational directions.

The seal generally comprises a frame, a rubber member bonded to the frame, and a rubber seal lip 1 in contact with a bearing inner race 2. The sealing device is arranged between the bearing inner ring 2 and the bearing outer ring, and the sealing lip 1 and the bearing inner ring 2 form contact sealing. Taking the bearing mounted on the robot arm as an example, the robot arm needs to perform the action of the swing arm for grabbing and retracting, so that the bearing needs to rotate slowly in both directions at a low speed, usually less than 30rpm, and the rotating direction is frequently switched. As shown in fig. 1, an open arrow a represents a bearing rotation direction, and a solid arrow B above the seal lip 1 represents a radial force (a force for making the seal lip 1 abut against the bearing inner ring 2), when the bearing rotates, grease rotates along with the inner ring, and due to friction between the seal lip 1 and the bearing inner ring 2, the seal lip 1 is expanded and deformed at the bearing inner ring 2 to form a wrinkle (as shown by a wavy broken line in fig. 1), and the wrinkle can pump the grease on the seal lip 1 back to the inside (i.e., the left side in fig. 1) of the bearing. The dense arrows below the bearing inner ring 2 represent the C pressure profile, which is determined by the shape of the corrugations in the figure. As shown in fig. 2, when the rotation direction is suddenly switched, the rotation direction of the bearing inner ring 2 is immediately changed (the direction of an open arrow a), and the wave-shaped direction of the fold on the seal lip 1 in contact with the bearing inner ring 2 is switched, but the movement direction of the grease cannot be changed in a short time due to a low rotation speed, and when the fold with the changed direction (shown by the wave-shaped broken line in fig. 2) is encountered, the grease moves toward the outer side of the bearing (i.e., the right side in fig. 2) under the pumping action of the fold, so that the grease is easy to leak.

In order to improve the sealing performance of the knuckle arm bearing, the embodiment of the invention provides a sealing device, in the working process of the bearing, relative rotation is generated between a plastic part and a bearing inner ring, because the friction coefficient of the material of the plastic part is smaller than that of the material of the elastic part, the friction force between the plastic part and the bearing inner ring is smaller than that between the elastic part and the bearing inner ring, and wrinkles are not easily generated on the surface of the plastic part, which is in contact with the bearing inner ring, therefore, even if the bearing suddenly changes the rotating direction, grease cannot timely change along with the rotating direction, the phenomenon that the grease moves along the axial direction due to the pumping action of the wrinkles is not generated, the grease leakage between the bearing inner ring and the plastic part when the rotating direction of the bearing inner ring is suddenly changed can be improved, the sealing effect of the sealing device is improved, and further, the friction force between the plastic part and the bearing inner ring is reduced, the service life of the sealing device can be prolonged.

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

It should be noted that unless otherwise stated, axial, radial and circumferential refer to axial, radial and circumferential, respectively, of the sealing device; the axially outer end is referred to the right in fig. 3-7 and the axially inner end is referred to the left in fig. 3-7; the radially outer side means a side (upper side in fig. 3 to 7) away from the center axis of the seal device in the radial direction, and the radially inner side means a side (lower side in fig. 3 to 7) close to the center axis of the seal device in the radial direction.

The embodiment of the invention provides a sealing device which is suitable for being arranged between a bearing inner ring and a bearing outer ring, and comprises:

a framework;

the sealing part is wholly of an annular structure and comprises an elastic part and a plastic part, the elastic part is fixed on the framework, when the sealing device is arranged between the bearing inner ring and the bearing outer ring, the plastic part and the bearing inner ring form contact sealing, the elastic part and the plastic part are relatively fixed and at least partially arranged in the radial direction, the plastic part is arranged between the bearing inner ring and the elastic part, and the friction coefficient of the material of the plastic part is smaller than that of the material of the elastic part.

It should be noted that, the elastic portion and the plastic portion are relatively fixed, which means that the elastic portion and the plastic portion are relatively stationary during the operation of the sealing device. Therefore, before the sealing device is arranged between the bearing inner ring and the bearing outer ring, the elastic part and the plastic part can be directly fixed together or can be not contacted, so long as the elastic part and the plastic part are relatively fixed after the sealing device is arranged between the bearing inner ring and the bearing outer ring. For example, in one embodiment, the elastic portion and the plastic portion may be directly adhered together, with the plastic portion being disposed between the bearing inner race and the elastic portion in the radial direction; in another embodiment, the elastic portion and the plastic portion may also be 2 separate components, and after the plastic portion is mounted on the bearing inner ring, the elastic portion abuts against the plastic portion by other external force (e.g., spring force), so that the elastic portion and the plastic portion are relatively fixed. Of course, in another embodiment, both the elastic portion and the plastic portion may be fixed to the frame, achieving relative fixation of the elastic portion and the plastic portion.

Specifically, referring to fig. 3, fig. 3 is a partial schematic view of a sealing device according to an embodiment of the present invention. It will be appreciated by those skilled in the art that only a portion of the cross-sectional view of the sealing device is illustrated in figure 3.

As shown in fig. 3, in a specific embodiment, the plastic part 20 is a ring-shaped structure integrally, and includes an outer ring fixing end 210 and an inner ring free end 220, the outer ring fixing end 210 is fixed to the outer axial end surface of the frame 30, when the sealing device is disposed between the inner ring and the outer ring of the bearing, the inner ring free end 220 can be bent along the axial direction of the sealing device (refer to fig. 5), and is disposed between the inner ring of the bearing and the elastic part 10 in the radial direction, and the elastic part 10 is fixed relative to the inner ring free end 220. By fixing the plastic part 20 to the frame 30, the firmness is improved, the plastic part 20 is prevented from moving along the axial direction, and the end face of the plastic part 20 is ensured to be parallel to the end faces of other parts (the bearing inner ring and the bearing outer ring 40) of the bearing. After installation, the inner ring free end part 220 can be bent along the axial direction of the sealing device and is arranged between the bearing inner ring and the elastic part 10 in the radial direction, so that the contact area between the plastic part 20 and the bearing inner ring can be increased, and a space is provided for the subsequent arrangement of the annular groove 200 on the inner ring free end part 220.

In order to improve the contact force between the free end 220 of the inner ring and the inner ring of the bearing, the sealing device may further include a spring 80 having an overall annular structure, which is fitted around the outer annular surface of the elastic part 10 and is disposed on the cross section where the elastic part 10, the plastic part 20 and the inner ring of the bearing coexist. Taking fig. 7 as an example, the spring 80 is disposed on a cross section where the elastic portion 10, the inner ring free end portion 220 and the bearing inner race 50 coexist.

Referring to fig. 4 and 5, in the installation, the plastic part 20 is first bent as shown in fig. 5 by the installation tool, and then the installation tool is pulled out, so that the inner ring free end portion 220 of the plastic part 20 is brought into close contact with the bearing inner ring 50 (shown in fig. 7), and at the same time, the contact force between the plastic part 20 and the bearing inner ring is increased by the elastic part 10 mounted with the loading spring 80 abutting against the plastic part 20.

The coefficient of friction of the material of the plastic part 20 is smaller than the coefficient of friction of the material of the elastic part 10. Specifically, the material of the plastic part 20 may be Polytetrafluoroethylene (PTFE). The PTFE friction coefficient is extremely low, the friction torque of the sealing device can be greatly reduced, the abrasion of the plastic part 20 is reduced, and the service life of the sealing device can be prolonged. Of course, in other embodiments, the plastic part may be made of other materials with lower friction coefficient, so as to reduce the possibility that the plastic part at the joint with the bearing inner ring is deformed due to friction force, thereby improving the sealing performance of the sealing device.

In the sealing device provided by the embodiment of the invention, after the sealing device is arranged between the bearing inner ring and the bearing outer ring, the plastic part and the bearing inner ring form contact sealing, the elastic part and the plastic part are relatively fixed, and the plastic part is arranged between the bearing inner ring and the elastic part in the radial direction, so that in the working process of the bearing, the plastic part and the bearing inner ring generate relative rotation, because the friction coefficient of the material of the plastic part is smaller than that of the material of the elastic part, and the friction force between the plastic part and the bearing inner ring is smaller than that between the elastic part and the bearing inner ring, the surface of the plastic part, which is in contact with the bearing inner ring, is not easy to generate wrinkles, and therefore, even if the bearing suddenly changes the rotation direction, the grease cannot be timely changed along with the rotation direction, and the phenomenon that the grease moves along the axial direction due to the pumping action of the wrinkles is avoided, therefore, when the bearing inner ring changes the rotating direction suddenly, the grease leakage between the bearing inner ring and the plastic part can be improved, the sealing effect of the sealing device is improved, the friction force between the plastic part and the bearing inner ring is further reduced, and the service life of the sealing device can be prolonged.

With continued reference to fig. 3, in one embodiment, the inner ring free end 220 defines an annular groove 200, and the annular groove 200 opens toward the inner race when the inner ring free end 220 is disposed between the inner race and the outer race 40. Once a small amount of grease flows axially outward, the grease is retained in the annular groove 200 from continuing to flow axially outward, further improving the sealing effect of the seal.

The shape of the annular groove 200 is not limited, and the number of the annular grooves 200 may be 1 or at least 2.

Referring to fig. 4 and 5, in order to enhance the fixing effect of the plastic part 20, in a specific embodiment, the sealing device may further include: and the stop ring 70 is fixed on the framework 30, and the stop ring 70 and the framework 30 are respectively arranged at two axial ends of the plastic part 20. When the sealing device is installed on the bearing inner ring, in the process that the inner ring free end part 220 of the plastic part is axially bent, the outer ring fixed end part 210 of the plastic part is limited in an axial area enclosed by the framework 30 and the stop ring 70, and the outer ring fixed end part 210 can be prevented from falling off the framework 30 due to the tendency of moving away from the framework 30 in the axial direction.

Specifically, the stop ring 70 may include an axial portion and a radial portion that are fixedly connected, the radial portion of the stop ring 70 is in interference fit with the framework 30, the plastic portion 20 is located between the axial portion and the framework 30, the axial portion of the stop ring 70 is in interference fit with the plastic portion 20, and the plastic portion 20 may also be directly adhered between the framework 30 and the stop ring 70. Of course, in other embodiments, the sealing device may not include a stop ring, and the outer ring fixing end face of the plastic part is directly attached to the outer end face of the radial part of the frame in order to reduce the cost.

Referring to fig. 5, in one embodiment, the plastic part 20 further includes a thrust surface 60, and the thrust surface 60 is located at an axially inner end of the plastic part 20 when the plastic part 20 forms a contact seal with the bearing inner race.

It will be readily appreciated that the thrust surfaces are sloped, i.e. they are not perpendicular to the axis but form an angle (non-perpendicular) with the axis, and that, for example, in fig. 5, grease is located on the left side of fig. 5, and when grease accumulates on the inner ring free end portion 220 of the plastic portion 20, the thrust surfaces as sloped surfaces can trap the grease, and the thrust surfaces 60 help to prevent further grease flow in the axially outer end direction.

Further, with reference to fig. 5, under the condition that the bearing needs to rotate slowly in two directions, the thrust surfaces 60 are uniformly distributed along the circumferential direction of the plastic part 20, and the slope directions of adjacent thrust surfaces 60 are symmetrical with respect to the boundary line of adjacent thrust surfaces 60. Thus, the thrust surface 60 serves to urge grease back toward the axially inner end to prevent further grease flow toward the axially outer end, regardless of whether the bearing is rotating in the forward or reverse direction.

Referring to fig. 6, in an embodiment, the plastic part 20 may further include:

and a dust lip 230 fixed to an axially outer end surface of the annular fixed end portion, wherein when the inner ring free end portion 220 is disposed between the inner ring and the outer ring 40, the dust lip 230 extends in a direction axially away from the inner ring free end portion 220 and radially close to the inner ring. Because the dust lip 230 is disposed at the axial outer end, the dust lip 230 can block dust and a small amount of splash water, and the sealing effect of the sealing device is further improved.

Referring to fig. 7, to solve the above problem, an embodiment of the present invention further provides a bearing, which includes a bearing inner ring 50, a bearing outer ring 40, and the above sealing device, where the sealing device is disposed between the bearing inner ring and the bearing outer ring 50.

In the bearing working process, relative rotation is generated between the plastic part and the bearing inner ring, and therefore the friction coefficient of the material of the plastic part is smaller than that of the material of the elastic part, the friction force between the plastic part and the bearing inner ring is smaller than that between the elastic part and the bearing inner ring, and wrinkles are not easily generated on the surface of the plastic part, which is in contact with the bearing inner ring, so that even if the bearing suddenly changes the rotating direction, the grease cannot timely change along with the rotating direction, and the phenomenon that the grease moves along the axial direction due to the pumping action of the wrinkles is avoided, so that the grease leakage between the bearing inner ring and the plastic part can be improved when the rotating direction of the bearing inner ring is suddenly changed, the sealing effect of the bearing is improved, further, the friction force between the plastic part and the bearing inner ring is reduced, and the service life of the bearing can be prolonged.

Although the embodiments of the present invention have been disclosed, the present invention is not limited thereto. Various changes and modifications may be effected therein by one skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.