CN111895095A

CN111895095A - Seal assembly

Info

Publication number: CN111895095A
Application number: CN201910371541.8A
Authority: CN
Inventors: 刘鑫; 李定; 蔡向阳; 王臻颖
Original assignee: Schaeffler Technologies AG and Co KG
Current assignee: Schaeffler Technologies AG and Co KG
Priority date: 2019-05-06
Filing date: 2019-05-06
Publication date: 2020-11-06

Abstract

The invention relates to a sealing assembly for sealing between a first member and a second member which can rotate relatively, the sealing assembly is annular and comprises a framework and a sealing part, and the sealing part comprises a first main sealing lip extending from the radial inner end part of the framework towards the axial inner side and towards the radial inner side. The seal assembly also includes a second primary seal lip disposed radially spaced from the first primary seal lip, and a dust guard including a first edge extending generally axially of the seal assembly for fixedly mounting the dust guard to the first member, a second edge and a third edge extending generally axially, the first primary seal lip being configured to form a contact seal with the first member or the first edge, the second primary seal lip being configured to form a contact seal with the third edge, such that the dust guard, the first primary seal lip, the second primary seal lip, and a portion of the skeleton and/or seal between the first primary seal lip and the second primary seal lip circumscribe a seal cavity.

Description

Seal assembly

Technical Field

The present invention relates to the field of seals, and more particularly to a seal assembly for use between first and second members of an electric drive hub (IWD) that are rotatable relative to each other.

Background

For an electric drive wheel hub for a vehicle, it generally comprises a first member (e.g. a shaft of an electric motor) and a second member (e.g. a gear box) which are capable of rotating relative to each other, wherein the shaft of the electric motor is capable of rotating relative to the gear box, and a contact-type seal assembly is employed between the shaft of the electric motor and the gear box to form a sealed space between the gear box and the seal assembly, which can prevent oil (e.g. lubricating oil) inside the gear box from entering the electric motor and simultaneously prevent dust and other impurities of the external environment from entering the interior of the gear box.

In the prior art, sealing is generally performed in an electric drive hub using a seal assembly as shown in fig. 1, where the left side is the oil side and the right side is the environment side. The seal assembly is generally ring-shaped and, as shown in the partial cross-sectional view of fig. 1, includes a frame 10, a seal portion 20, and a spring 30 assembled together.

Specifically, the skeleton 10 is made of a hard material such as metal and includes: a backbone axial portion 101 extending generally along an axial direction a of the seal assembly; a backbone radial portion 103 extending generally along a radial direction R of the seal assembly; and a carcass connecting portion 102 as a transition between the carcass axial portion 101 and the carcass radial portion 103.

On the other hand, the seal portion 20 is attached to the bobbin 10, and particularly, is attached mostly to the ends of the bobbin axial portion 101, the bobbin connecting portion 102, and the bobbin radial portion 103. Specifically, the seal portion 20 includes a main seal lip 21 extending from a radially inner end of the bobbin radial portion 103 to, for example, a shaft 40 of the electric motor, whereby a seal space K is formed surrounded on the inside of the seal assembly by the seal portion 20 on the upper side in the drawing, the main seal lip 21 on the lower side in the drawing, and the bobbin 10. Furthermore, the method is simple. The main seal lip 21 is abutted against the surface of the shaft 40 by the spring 30 in the seal space K on the radially outer side thereof, and a spring force toward the radially inner side is always applied to the main seal lip 21 by the spring 30, so that the main seal lip 21 achieves contact sealing with the shaft 40 with its wedge-shaped contact portion.

The sealing assembly with the structure is mainly used for an electric driving hub in an automobile. Leakage is a particular concern for sealing systems. In most cases of seal failure, the resulting leakage can have many adverse consequences.

Disclosure of Invention

The present invention has been made in view of the above-mentioned drawbacks of the prior art. The invention aims to provide a sealing assembly, which can improve the sealing performance and reduce the possibility of leakage without additionally increasing the overall size or space requirement of the sealing assembly by fully utilizing the internal sealing space and adding an additional sealing structure therein.

In order to achieve the above object, the present invention may adopt the following technical solutions.

The invention provides a sealing assembly for sealing between a first member and a second member which can rotate relatively, the sealing assembly is annular and comprises a framework and a sealing part, the framework is used for being fixedly installed on the second member, and the sealing part comprises a first main sealing lip extending from the radial inner end of the framework towards the axial inner side and towards the radial inner side. In particular, the seal assembly further includes a second primary seal lip disposed radially spaced from the first primary seal lip and a dust shield, the dust guard includes a first side extending generally in an axial direction of the seal assembly, a second side and a third side extending generally in the axial direction, the second edge connecting the first edge and the third edge, the first edge for fixedly mounting the dust guard to the first member, the first primary seal lip is configured to form a contact seal with the first member or the first edge, the second primary seal lip is configured to form a contact seal with the third side such that the dust guard, the first primary seal lip, the second primary seal lip, and a portion of the skeleton and/or the seal portion between the first primary seal lip and the second primary seal lip define a seal cavity therearound.

In at least one embodiment, the second primary seal lip has a similar configuration and size as the first primary seal lip.

In at least one embodiment, a first spring is disposed radially outward of the first primary seal lip and exerts a spring force on the first primary seal lip toward a radially inward side. The second main seal lip extends from an axial inner side surface of a radial portion of the frame toward a radial inner side and also toward the axial inner side, wherein a second spring is provided on a radial outer side of the second main seal lip, and the second spring applies a spring force toward the radial inner side to the second main seal lip.

In at least one embodiment, the second primary sealing lip has the configuration of an arc-shaped thin plate and extends arcuately towards the radially inner side and simultaneously towards the axially inner side.

In at least one embodiment, a thickness of the second primary seal lip in the radial direction is less than a thickness of the first primary seal lip in the radial direction of the seal assembly.

In at least one embodiment, the radially outer side of the second primary seal lip is free of springs that exert a spring force thereon.

In at least one embodiment, the second primary seal lip contacts the third side in an arcuate portion having a length.

In at least one embodiment, the axial cross section of the second primary seal lip has an overall arcuate profile that is convex toward the radially inner side.

In at least one embodiment, the second primary seal lip is disposed radially intermediate the backbone.

In at least one embodiment, a first primary seal lip is in contact with the first side and a second primary seal lip is in contact with a radially outward face of the third side.

Drawings

FIG. 1 is a partial cross-sectional schematic view of a prior art seal assembly.

Fig. 2 is a schematic view, partly in section, of a sealing assembly according to a first embodiment of the invention.

Fig. 3 is a schematic view, partly in section, of a sealing assembly according to a second embodiment of the invention.

Description of the reference numerals

10 framework 101 framework axial portion 102 framework connecting portion 103 framework radial portion 20 sealing portion 21 first main sealing lip 201 first main sealing lip 202 second main sealing lip 30 spring 31 first spring 32 second spring 40 shaft 50 first side 52 second side 53 third side a axial direction R radial direction K sealing space.

Detailed Description

The following detailed description of the invention refers to the accompanying drawings that illustrate specific embodiments of the invention. The overall shape of the seal assembly of the present invention is annular. Unless otherwise specified, "axial" and "radial" as used in the following detailed description refer to the axial and radial directions of the seal assembly, respectively. In the following embodiments, the axially outer side (environment side) is the right side in the drawings, and the axially inner side (sealed side/lubricant side/oil side) is the left side in the drawings; the radially outer side is the upper side in the drawings, and the radially inner side is the lower side in the drawings.

A number of exemplary embodiments according to the present invention will be described below.

(first embodiment)

In the present embodiment, as shown in fig. 2, the seal assembly mainly includes a frame 10 and a seal portion 20, wherein the seal portion 20 is attached to the frame 10. The frame 10 is preferably made of a hard material such as metal, and the sealing part 20 is preferably made of an elastic material such as rubber.

The construction of the skeleton 10 in this embodiment is substantially the same as that of the skeleton 10 of the prior art seal assembly shown in fig. 1. As shown in FIG. 2, the armature 10 includes an armature axial portion 101 extending generally in the axial direction A of the seal assembly and an armature radial portion 103 extending generally in the radial direction R of the seal assembly, wherein the armature axial portion 101 is adapted to be fixedly secured to a second member. Here, "substantially along the axial direction a of the sealing assembly" means not absolutely parallel to the axial direction a, but with possible minor deviations. "generally along the radial direction R of the seal assembly" also means similar.

The structure of the seal portion 20 in the present embodiment is partially the same as that of the seal portion 20 of the related art seal assembly shown in fig. 1. As shown in fig. 2, the seal portion 20 includes a first main seal lip 201 extending from a radially inner end of the skeleton radial portion 103 toward the axially inner side while facing the radially inner side. The first primary seal lip 201 can apply a spring force toward the radially inner side to the first primary seal lip 201 by the first spring 31 located on the radially outer side thereof.

In the present embodiment, in the seal space K, a second main seal lip 202 is preferably provided at a radially intermediate position (not necessarily the midpoint) of the skeleton radial portion 103, radially spaced from the first main seal lip 201, the second main seal lip 202 having a similar configuration and size to the first main seal lip 201, also extending from the axially inner side face of the skeleton radial portion 103 toward the radially inner side and simultaneously toward the axially inner side, and a spring force toward the radially inner side may be applied to the second main seal lip 202 by a second spring 32 located on the radially outer side thereof. The extension angle of the second main seal lip 202 may be the same as or different from that of the first main seal lip 201, and the extension length of the second main seal lip 202 may be the same as or different from that of the first main seal lip 201. The second primary sealing lip 202 can divide the sealed space K into two portions having similar volumes. The position of the second primary seal lip 202 in the radial direction may be changed as desired.

In particular, in the present embodiment, there is also provided a dust-proof 50 made of, for example, a metal plate, which is annular in shape having a substantially U-shaped cross section (axial section) and includes a first side 51, a second side 52, and a third side 53. As shown in fig. 2, the cross section of the dust-proof member 50 is a U shape of a side, the length directions of the first side 51 and the third side 53 which are approximately parallel to each other are parallel or approximately parallel to the axial direction a, and the length direction of the second side 52 is parallel to the radial direction R, wherein the dust-proof member 50 is assembled on the shaft 40 in such a manner that the first side 51 is interference-fitted, so that the dust-proof member 50 rotates together with the shaft 40 due to a large contact force with the shaft 40, wherein a sealing effect is achieved between the dust-proof member 50 and the shaft 40.

The radially inward spring force exerted on the first primary seal lip 31 by the first spring 31 forms a contact seal between the wedge-shaped contact portion of the first primary seal lip 201 and the first edge 51 (radially outer surface) of the dust guard 50, enhancing the sealing effect, and the surface roughness of the first edge 51 toward the first primary seal lip 201 is small, so that the friction force and the friction torque therebetween are not large, and the wear of the first primary seal lip 201 can be reduced. At the same time, the third side 50 of the dust prevention member 50 is in contact with the wedge-shaped contact portion of the second main seal lip 202, and a contact seal is formed between the wedge-shaped contact portion of the second main seal lip 32 and the third side 53 (the radially outer side surface thereof) of the dust prevention member 50 by the second spring 32. Thus, the dust guard 50, the first main seal lip 201, the second main seal lip 202, and the portion of the skeleton 10 (the skeleton radial portion 103) and/or the seal portion 20 between the first main seal lip 201 and the second main seal lip 202 define the seal cavity G around. Similarly, the surface roughness of the third side 53 toward the second main seal lip 202 is small, so that the frictional force and the frictional torque therebetween are not large, and thus the wear of the second main seal lip 202 can be reduced. According to the present invention, the second main seal lip 202 can achieve the sealing effect of the conventional seal assembly, isolate the medium such as the lubricating oil, and even if a small amount of the lubricating oil breaks through the seal of the second main seal lip 202, the first main seal lip 201 can further perform the sealing, and the lubricating oil reaching the second main seal lip 202 can play a role of lubricating it. By the multiple sealing structure, the overall sealing effect of the sealing assembly is obviously enhanced compared with the traditional sealing assembly.

(second embodiment)

As shown in fig. 3, the basic structure of the seal assembly according to the present embodiment is the same as that of the seal assembly according to the first embodiment, and their differences include the configuration of the second primary seal lip 202.

In the seal assembly according to the present embodiment, as shown in the sectional view of fig. 3, the second main seal lip 202 extends arcuately toward the radially inner side and simultaneously toward the axially inner side in an arcuate thin plate configuration, wherein the thickness of the second main seal lip 204 in the radial direction R is smaller than that of the first main seal lip 201 in the radial direction R, and the second main seal lip 202 contacts the third side 53 of the dust piece 50 in an arcuate portion having a certain length, thereby forming a seal.

Since the second main seal lip 202 has the configuration of an arc-shaped thin plate, the amount of interference with the third side 53 can be greater than that of the wedge-shaped contact portion with the third side 53 in the first embodiment, and therefore, a spring may not be provided for the second main seal lip 202, and thus, although the amount of interference of the second main seal lip 202 with the third side 53 is greater, the contact pressure thereof with the third side 53 can be reasonably controlled, so that large wear is less likely to occur.

It is to be understood that the amount of interference of the second main seal lip 202 with the third side 53 mentioned herein may refer to the maximum amount of deformation/displacement in the radial direction R of the portion of the second main seal lip 202 in contact with the third side 53 from the natural state of being unassembled together to the installed state of being assembled together.

Preferably, the axial cross section of the second primary seal lip 202 has an overall arc-shaped profile that is convex toward the radially inner side. Due to the fact that the elongated and curved configuration has the property of being easily deformed, a greater interference with, for example, a counterpart component, and thus a greater contact force, can be achieved even without an external force applied thereto by a spring or the like, as opposed to the wedge-shaped contact portion of the second primary seal lip 202 in the first embodiment, thereby achieving a better sealing action.

Although the above embodiments have described the specific technical solutions of the present invention in detail, it should be noted that:

(1) although the second primary seal lip 202 has been described as having the configuration of an arc-shaped thin plate in the above-described embodiment, the present invention is not limited thereto, and the first primary seal lip 201 may also have the configuration of an arc-shaped thin plate.

(2) The thickness and material of the dust-proof member 50 may be selected according to the requirement of interference fit.

(3) The second primary seal lip 202 may be made of the same or different material as the first primary seal lip 201, including but not limited to fluoro-rubber (FKM), acrylate rubber (ACM), and the like.

Claims

1. A seal assembly for sealing between a first and a second relatively rotatable member, the seal assembly being generally annular and comprising a skeleton (10) for fixed mounting to the second member and a seal portion (20), the seal portion (20) comprising a first primary seal lip (201) extending from a radially inner end of the skeleton (10) towards an axially inner side and towards a radially inner side,

the seal assembly further comprises:

a second primary seal lip (202) disposed radially spaced from the first primary seal lip (201); and

a dust guard (50), the dust guard (50) including a first side (51) extending generally along an axial direction (A) of the seal assembly, a second side (52), and a third side (53) extending generally along the axial direction (A), the second side (52) connecting the first side (51) and the third side (53), the first side (51) for fixedly mounting the dust guard (50) to the first member, the first primary seal lip (201) configured to form a contact seal with the first member or the first side (51), the second primary seal lip (202) configured to form a contact seal with the third side (53) such that the dust guard (50), the first primary seal lip (201), the second primary seal lip (202), and a portion of the skeleton and/or the seal between the first primary seal lip (201) and the second primary seal lip (202) define a seal around the dust guard (50), the first primary seal lip (201), the second primary seal lip (202), and a portion of the skeleton and/or the seal portion between the first primary seal lip (201) and the second primary seal lip (202) And a cavity (G) is sealed.

2. The seal assembly of claim 1, wherein the second primary seal lip (202) has a similar configuration and dimensions as the first primary seal lip (201).

3. A seal assembly according to claim 2, characterized in that a first spring (31) is arranged radially outside the first primary seal lip (201), which first spring (31) exerts a spring force on the first primary seal lip (201) directed radially inwards,

the second main seal lip (202) extends from an axial inner side surface of a frame radial portion (103) of the frame (10) toward a radial inner side and also toward the axial inner side, wherein a second spring (32) is provided radially outside the second main seal lip (202), and the second spring (32) exerts a spring force toward the radial inner side on the second main seal lip (202).

4. The seal assembly of claim 1, wherein the second primary seal lip (202) has an arcuate web configuration and extends arcuately toward a radially inner side and simultaneously toward an axially inner side.

5. The seal assembly according to claim 4, characterized in that the thickness of the second primary seal lip (202) in the radial direction (R) of the seal assembly is smaller than the thickness of the first primary seal lip (201) in the radial direction (R).

6. The seal assembly of claim 4, wherein a radially outer side of the second primary seal lip (202) is free of a spring exerting a spring force thereon.

7. The seal assembly of claim 5, wherein the second primary seal lip (202) contacts the third side (53) in an arcuate portion having a length.

8. The seal assembly of claim 7, characterized in that the axial cross section of the second primary seal lip (202) has overall an arcuate profile that is convex towards the radially inner side.

9. The seal assembly according to any one of claims 1 to 8, characterized in that the second primary sealing lip (202) is arranged in a radially intermediate position of the skeleton (10).

10. The seal assembly according to any one of claims 1 to 8, characterized in that the first main sealing lip (201) is in contact with the first edge (501) and the second main sealing lip (202) is in contact with a radially outer side of the third edge (503).