Sealing device

Abstract

This invention relates to a sealing device for dynamic sealing. The sealing device includes a frame, an elastic sealing body, and a dust cover. All three are coaxially arranged in annular shapes. The elastic sealing body is fixed radially inward of the frame. The dust cover has an axial section extending radially inward of the elastic sealing body and a folded section located on the first axial side of the frame. An annular sealing cavity is formed between the axial section and the folded section. The axial end of the sealing cavity facing the frame is open, and the axial end away from the frame is closed. The elastic sealing body includes a lip section extending continuously in a zigzag shape within the sealing cavity. The ends and bends of the lip section form multiple sealing lips that mate with the inner wall of the sealing cavity. A labyrinthine channel is formed around the lip section between it and the inner wall of the sealing cavity. The sealing device of this invention exhibits low friction and high reliability.

Description

Technical Field

[0001] This invention relates to the field of sealing technology. Specifically, this invention relates to a sealing device for dynamic sealing. Background Technology

[0002] In components involving relative rotation, such as bearings, dynamic sealing devices are often required. For example, tapered roller bearings (TAROL) used in the wheelset axle heads of railway vehicles are typically equipped with shaft seals. Such seals generally consist of a skeleton, a resilient seal body, and a spring. The resilient seal body has a main lip, which is spring-loaded, and a dust lip to prevent the ingress of external particles. After the seal is pressed into the bearing, the skeleton remains relatively stationary with respect to the bearing's outer ring, while a portion of the resilient seal body (the main lip) contacts the bearing's inner ring or the wear-resistant sealing ring.

[0003] When the bearing rotates, the lubricating grease stored inside is thrown onto the inner wall of the bearing housing and accumulates. Eventually, the grease leaks through the gap between the sealing lip and the inner ring or the wear-resistant sealing ring. The root cause of this leakage is that the presence of the spring increases the friction between the main lip and the wear-resistant sealing ring, leading to faster lip wear. Furthermore, high temperatures are easily generated in localized areas of the sealing lip during relative rotation, causing the accumulated grease to thin and be squeezed out of the gap. Simultaneously, due to the high frictional torque, this type of sealing device is not suitable for high-speed rail vehicle products, and prolonged periods of inactivity may allow external contaminants to enter the bearing.

[0004] To address the aforementioned technical problems, existing technologies often employ the addition of multiple layers of light-contact or non-contact lips to improve the reliability of the sealing effect. For example, CN 106151522A discloses a box-type sealing assembly in which two second lips mate with a dust cover. In this design, springs are still retained, therefore the friction remains significant. Summary of the Invention

[0005] Therefore, the technical problem that this invention needs to solve is to provide a sealing device with low friction and high reliability.

[0006] The aforementioned technical problem is solved by a sealing device according to the present invention. The sealing device includes a frame, an elastic sealing body, and a dust cover, all three being coaxially arranged annular structures. The elastic sealing body is fixed radially inner to the frame. The dust cover has an axial section extending radially inner to the elastic sealing body and a folded section located on a first axial side of the frame. The folded section folds back from the end of the axial section toward the frame, thereby forming an annular sealing cavity between the axial section and the folded section. The axial end of the sealing cavity facing the frame is an open end, while the axial end away from the frame is a closed end. The elastic sealing body includes a lip section extending continuously in a zigzag shape within the sealing cavity. The end and turning portion of the lip section form multiple sealing lips that mate with the inner wall of the sealing cavity, forming a labyrinthine channel around the lip section between the lip section and the inner wall of the sealing cavity. The lip section can be continuously bent multiple times according to the size of the sealing cavity, for example, forming an N-shaped zigzag structure. This construction creates multiple sealing lips at the ends and bends of the lip section, which can form either a contact seal or a non-contact seal with the inner wall of the sealing cavity. During installation, the first axial side where the reverse bend section is located is the outer side of the bearing. Lubricating grease or other liquids leaking from the inside of the bearing (i.e., the liquid seal side) or contaminants infiltrating from the outside need to flow along the tortuous channel between the lip section and the inner wall of the sealing cavity, and must pass through multiple sealing lips, thus achieving a labyrinth seal effect. Therefore, a reliable low-friction seal can be obtained without spring loading.

[0007] According to a preferred embodiment of the present invention, the first end of the lip segment near the skeleton constitutes a shaft lip that mates with the axial segment. The lip segment extends continuously in a zigzag pattern from the first end between the inner wall of the outer diameter side and the inner wall of the inner diameter side of the sealing cavity. The turning portion of the lip segment constitutes a plurality of sealing lips that mate with either the inner wall of the outer diameter side or the inner wall of the inner diameter side. Preferably, the fit between the shaft lip and the axial segment can be a contact fit, i.e., the shaft lip is a contact lip that contacts the axial segment. The shaft lip is located near the liquid sealing side in the labyrinth channel, primarily serving as a lip to prevent leakage of liquids such as lubricating grease. Furthermore, preferably, the second end of the lip segment constitutes a sealing lip that mates with the closed end.

[0008] According to a further preferred embodiment of the present invention, a gap exists between the sealing lip formed by the bend and the second end of the lip body segment and the inner wall of the sealing cavity. The sealing lip formed by the bend and the second end of the lip body segment is located near the outer side in the labyrinth channel, primarily serving as a dustproof lip to prevent external particles from entering the liquid sealing side. More preferably, a light-contact lip is formed on the bend and / or the second end of the lip body segment, respectively, to contact the inner wall of the sealing cavity. The thickness of the light-contact lip is less than the thickness of the lip body segment, resulting in relatively small contact force with the dustproof cover, thus reducing friction and enhancing the sealing effect.

[0009] According to another preferred embodiment of the invention, the dust cover further includes a radial section located on a second axial side of the skeleton opposite to the first axial side, and the resilient seal also includes a radial lip extending toward the radial section. Preferably, the radial lip is a contact lip that contacts the radial section. The second axial side where the radial section is located is the liquid-sealing side inside the bearing, and the radial lip is the lip closest to the liquid-sealing side in the entire resilient seal, which helps to enhance the liquid-sealing effect by assisting the shaft lip. Attached Figure Description

[0010] The invention is further described below with reference to the accompanying drawings. In the drawings, the same reference numerals represent elements with the same function. Wherein:

[0011] Figure 1a and Figure 1b These are, respectively, a plan sectional view and a perspective sectional view of a sealing device according to an embodiment of the present invention;

[0012] Figure 2 yes Figure 1a and Figure 1b A schematic diagram showing the installation method of the sealing device on the bearing; and

[0013] Figure 3a and Figure 3b These are, respectively, a plan sectional view and a perspective sectional view of a sealing device according to another embodiment of the present invention. Detailed Implementation

[0014] The following describes specific embodiments of the sealing device according to the present invention in conjunction with the accompanying drawings. The detailed description and drawings below are provided to illustrate the principles of the invention, and the invention is not limited to the described preferred embodiments; the scope of protection of the invention is defined by the claims.

[0015] Reference Figure 1a and Figure 1bThe figures show partial plan sectional views and perspective sectional views of a sealing device 1 according to an embodiment of the present invention. As shown, the sealing device 1 includes three annular components arranged along the axis of rotation: a frame 10, an elastic sealing body 20, and a dust cover 30. The frame 10, made of a rigid material (e.g., metal), has a generally axially extending section and a generally radially extending section, wherein the generally axially extending section is used to fix to an external workpiece (e.g., a bearing outer ring), while the generally radially extending section is used to connect to and support the elastic sealing body 20. The frame 10 is divided into opposite sides in the axial direction: the first axial side (right side in the figure) is the external environment of the workpiece, i.e., the external side; while the second axial side (left side in the figure) is the sealing space inside the workpiece, i.e., the liquid sealing side. The elastic sealing body 20, made of an elastic material (e.g., rubber), is fixed to the inner diameter end of the generally radially extending section of the frame 10 by means of vulcanization or the like. A dust cover 30 (also called an oil slinger) made of a rigid material (e.g., metal) is fixed to an internal workpiece (e.g., a bearing inner ring), and the dust cover 30 is rotatable relative to the frame 10 (together with the resilient seal 20). The dust cover 30 comprises three integrally formed parts: an axial section 31, a folded section 32, and a radial section 33. The axial section 31 extends axially toward the radially inner side of the resilient seal 20 for fixing to the internal workpiece. The folded section 32 is a portion of the axial section 31 that folds back toward the frame 10 at one end. In this embodiment, the folded section 32 includes a section extending axially toward the frame 10 and a radially extending section connecting it to the axial section 31. In a longitudinal section of the dust cover 30, a rectangular space (annular in three-dimensional space) is formed between the axial section 31 and the folded section 32, referred to herein as a sealing cavity 34. The sealing cavity 34 opens toward the axial end of the frame 10 and closes away from the axial end of the frame 10. The radial section 33 extends radially outward from the liquid-sealed end of the axial section 31.

[0016] The elastic seal 20 has a lip segment extending in a continuous zigzag shape within the sealing cavity 34. The first end of the lip segment near the skeleton 10 abuts against the axial segment 31 of the dust cover 30, thus forming a axial lip 21 that engages with the axial segment 31 for a contact seal. The lip segment extends continuously from the first end between the outer diameter side inner wall (i.e., the axially extending portion of the folded segment 32) and the inner diameter side inner wall (i.e., the axial segment 31) of the sealing cavity 34, folding towards the opposite inner wall each time it reaches one side of the sealing cavity 34, and this can be repeated multiple times. Each bend in the lip segment forms a sealing lip that engages with the inner wall of the sealing cavity 34. In this embodiment, these bends form non-contact lips 23 that clearance-fit with the inner wall of the sealing cavity 34. The number of folds in the lip segment depends primarily on the spatial shape and size of the sealing cavity 34. In this embodiment, the lip section is folded back twice to form an N-shaped cross-sectional structure. Its second end terminates at the closed end of the sealing cavity 34 (i.e., the radially extending section of the folded section 32), thus forming another non-contact lip 23 that has a clearance fit with the inner wall of the sealing cavity 34. The elastic sealing body 20 also has a radial lip 22 that extends obliquely toward the radial section 33 of the dust cover 30. The radial lip 22 abuts against the radial section 33, thereby forming a contact seal.

[0017] Reference Figure 2 , which shows Figure 1a and Figure 1b The sealing device 1 is installed on the tapered roller bearing 2 in the following manner: The radial outer side of the frame 10 is fixed to the inner side of the outer ring of the bearing 2, while the axial section 31 of the dust cover 30 is fixed to the outer side of the sealing wear ring of the bearing 2, and the radial section 33 of the dust cover 30 abuts against the end face of the inner ring of the bearing 2, wherein the inner ring of the bearing 2 and the sealing wear ring are fixed relative to each other.

[0018] One advantage of this design is that a labyrinthine channel is formed between the lip section and the inner wall of the sealing cavity 34 through a zigzag structure, surrounding the outer side of the lip section. As shown by the arrow in Figure 1, liquids such as lubricating grease leaking outward from the liquid sealing side or contaminants invading inward from the outside need to flow along the tortuous channel between the lip section and the inner wall of the sealing cavity 34, and need to pass through multiple layers of sealing lips, thus achieving the effect of a labyrinth seal. Therefore, a reliable low-friction seal can be obtained without spring loading, making it more suitable for high-speed dynamic sealing. Among them, the shaft lip 21 and the radial lip 22 are close to the liquid sealing side in the labyrinth channel, mainly serving as lips to prevent the outward leakage of liquids such as lubricating grease; while the non-contact lip 23 formed by the bend of the lip section and the second end is close to the outside in the labyrinth channel, mainly serving as a dustproof lip to prevent external particles from entering the liquid sealing side.

[0019] Another advantage of this design is that, in the reverse-folding section 32, the two ends of each straight-line extension engage with different walls of the sealing cavity 34. In other words, two adjacent lips are the two ends of the reverse extension of the same elastic sealing body portion. When accumulated lubricating grease or contaminants cause localized compressive loads on the elastic sealing body 20, the two adjacent lips can be mutually supported in the sealing cavity 34 by means of the connecting lip sections, thereby greatly improving the overall structural strength of the elastic sealing body 20.

[0020] It should be noted that the construction of the folded section 32 in this embodiment is merely illustrative. Its purpose is to fold the dust cover 30 from its axial end on the outer side towards the liquid-sealing side, thereby forming an annular sealing cavity 34 opening towards the liquid-sealing side, which, together with the zigzag lip section, forms a labyrinthine passage. Therefore, the specific form of the folded section 32 is not limited to the construction shown in the figure, as long as it achieves the above objective. For example, the radially extending section of the folded section 32 can be formed into an arc-shaped structure, and the axially extending section of the folded section 32 can also extend obliquely about the axial direction. Alternatively, the folded section 32 can extend directly radially outward from the end of the axial section 31 of the dust cover 30 without the need for a radially extending section for transition.

[0021] See Figure 3a and Figure 3b The diagram shows partial plan sectional views and perspective sectional views of a sealing device 1 according to another embodiment of the present invention. Compared to Figure 1a and Figure 1b , Figure 3a and Figure 3b The difference in the sealing device 1 is that a light contact lip 24 is formed on each non-contact lip 23, which contacts the inner wall of the sealing cavity 34. The thickness of these light contact lips 24 is smaller than the thickness of the lip body section, so the pressure and friction on the contact surface are small, and the wear generated when the elastic seal 20 rotates relative to the dust cover 30 is also relatively small.

[0022] While possible embodiments have been described exemplarily in the foregoing description, it should be understood that numerous variations of embodiments exist through combinations of all known and readily conceived technical features and implementation methods. Furthermore, it should be understood that the exemplary embodiments are merely examples and do not in any way limit the scope, application, or construction of the invention. The foregoing description is more intended to provide those skilled in the art with technical guidance for transforming at least one exemplary embodiment, wherein various changes, particularly regarding the function and structure of the components, can be made without departing from the scope of the claims.

[0023] Appendix Label Table

[0024] 1. Sealing device

[0025] 2 bearings

[0026] 10. Skeleton

[0027] 20. Elastic sealing body

[0028] 21 Shaft lip

[0029] 22. Diameter of the lip

[0030] 23 Non-contact lip and mouth

[0031] 24. Lightly touch the lips.

[0032] 30 Dust Cover

[0033] 31 Axial section

[0034] 32. Reverse fold section

[0035] 33 Radial Section

[0036] 34 Sealed cavity

Claims

1. A sealing device for dynamic sealing, comprising a frame (10), an elastic sealing body (20), and a dust cover (30), wherein the frame (10), the elastic sealing body (20), and the dust cover (30) are all coaxially arranged annular structures, and the elastic sealing body (20) is fixed to the radially inner side of the frame (10). Its features are, The dust cover (30) has an axial section (31) extending radially inward from the elastic sealing body (20) and a folded section (32) located on the first axial side of the frame (10). An annular sealing cavity (34) is formed between the axial section (31) and the folded section (32). The sealing cavity (34) is open at its axial end facing the frame (10) and closed at its axial end away from the frame (10). The elastic seal (20) includes a lip segment that extends in a continuous zigzag shape in the sealing cavity (34). Each time the lip segment reaches one side of the inner wall of the sealing cavity (34), it folds and extends towards the opposite side of the inner wall. The end of the lip segment and each bend form a plurality of sealing lips that cooperate with the inner wall of the sealing cavity (34). A labyrinthine channel is formed between the lip segment and the inner wall of the sealing cavity (34) around the lip segment.

2. The sealing device according to claim 1, characterized in that, The first end of the lip section near the skeleton (10) forms an axial lip (21) that mates with the axial section (31). The lip section extends in a continuous zigzag shape between the outer diameter side inner wall and the inner diameter side inner wall of the sealing cavity (34) starting from the first end. The turning part of the lip section forms a plurality of sealing lips that mate with the outer diameter side inner wall or the inner diameter side inner wall.

3. The sealing device according to claim 2, characterized in that, The lip (21) of the shaft portion contacts the axial section (31).

4. The sealing device according to claim 2, characterized in that, The second end of the lip segment, away from the skeleton (10), forms a sealing lip that mates with the closing end.

5. The sealing device according to claim 4, characterized in that, There is a gap between the sealing lip formed by the turning part and the second end of the lip body segment and the inner wall of the sealing cavity (34).

6. The sealing device according to claim 5, characterized in that, A light contact lip (24) is formed on the turning portion and / or the second end of the lip body segment, respectively, to contact the inner wall of the sealing cavity (34), and the thickness of the light contact lip (24) is less than the thickness of the lip body segment.

7. The sealing device according to any one of claims 1 to 6, characterized in that, The dust cover (30) also includes a radial section (33) located on the second axial side of the skeleton (10), the second axial side being opposite to the first axial side, and the resilient seal (20) also includes a radial lip (22) extending toward the radial section (33).

8. The sealing device according to claim 7, characterized in that, The lip (22) of the radial portion contacts the radial section (33).

Images