Combined oil seal with reverse lip structure

Abstract

The invention provides a combined oil seal with a reverse lip structure, which comprises a lip I and a lip II which can be in contact sealing with a rotating shaft, an oil side angle alpha 1 is formed between a front lip of the lip I and the rotating shaft, and an air side angle beta 1 is formed between a rear lip of the lip I and the rotating shaft; the front lip of the lip II and the rear lip of the lip I are oppositely arranged; an air side angle beta'is formed between the front lip of the lip II and the rotating shaft, and an oil side angle alpha 'is formed between the rear lip of the lip I and the rotating shaft, so that the lip I and the lip II form a reverse lip structure. According to the design method of the combined oil seal with the reverse lip structure, for the combined oil seal, one lip can seal an oil medium, the other lip can resist foreign matter and water media, compared with a traditional oil seal, the foreign matter and water medium resisting sealing capacity can be remarkably improved, and the reliability of the oil sealing lip on the inner side can be guaranteed.

Description

Technical Field

[0001] The invention belongs to the technical field of sealing, relates to an oil seal structure, and in particular to a combined oil seal with a reverse lip structure. Background Art

[0002] Conventional oil seal structure such as Figure 1 As shown, the product consists of a metal skeleton, a rubber seal body, and a spring. The metal skeleton plays a supporting role in the oil seal structure. A dynamic seal is formed between the rubber seal body and the rotating shaft. The spring provides auxiliary clamping force to keep the oil seal lip and the shaft in contact at all times. According to the current oil seal sealing theory, the lip of the oil seal product adopts a wedge-shaped structure, with the oil side and the air side on both sides of the lip respectively. The key parameters of the lip are the front lip angle α (also called the oil side angle), the rear lip angle β (also called the air side angle), and the distance R between the center of the spring and the center of the lip (called the spring offset). The above structure will cause the oil seal lip to form a stress triangle distribution toward the oil side after contacting the shaft, as shown in the figure. Figure 2 As shown, due to the different angles on both sides (front lip angle > rear lip angle), a pumping effect toward the oil side is formed here, achieving sealing on the oil side.

[0003] The oil seal structure in the prior art is prone to cause sealing failure of the overall structure, especially for trace dust and water media, which is more likely to cause sealing failure of the overall structure. Summary of the Invention

[0004] In view of the shortcomings of the existing technology, the purpose of the present invention is to provide a combined oil seal with a reverse lip structure to solve the technical problem that the ability of the combined oil seal structure in the existing technology to resist trace dust and water media needs to be further improved.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0006] A combined oil seal with a reverse lip structure includes a No. 1 lip capable of contacting and sealing with a rotating shaft, wherein an oil-side angle α1 is formed between the front lip of the No. 1 lip and the rotating shaft, and an air-side angle β1 is formed between the rear lip of the No. 1 lip and the rotating shaft.

[0007] It also includes a No. II lip that can be in contact and sealed with the rotating shaft. The No. II lip is located on the rear side of the No. I lip, and the front lip of the No. II lip is arranged opposite to the rear lip of the No. I lip.

[0008] The front lip of the No. II lip forms an air side angle β' with the rotation axis, and the rear lip of the No. I lip forms an oil side angle α' with the rotation axis, so that the No. I lip and the No. II lip form a reverse lip structure.

[0009] The present invention also has the following technical features:

[0010] The oil side angle α1>the air side angle β1, and the oil side angle α'>the air side angle β'.

[0011] α1=40~50°, β1=17~25°, R1=0.2~0.7; α′=40~50°, β′=17~25°,

[0012] R'=0.2~0.7;

[0013] in:

[0014] R is the spring offset of lip No. I;

[0015] R' is the spring deflection of lip II.

[0016] α1=α';β 1＝ β'; R' = -R, where - represents the reverse direction.

[0017] The No. I lip is a wedge-shaped lip; the No. II lip is a wedge-shaped lip.

[0018] It also includes a No. II frame, a No. II rubber sealing body is installed on the No. II frame, and a No. II lip is provided on the No. II rubber sealing body.

[0019] Static sealing is achieved between the No. II frame and the mounting hole of the No. II frame by using rubber interference fit.

[0020] It also includes a No. 1 frame, on which a No. 1 rubber sealing body is installed, and on which a No. 1 lip is provided.

[0021] Frame I is connected to frame II by means of interference fit through rubber, so that static sealing is achieved between frame I and frame II.

[0022] Compared with the prior art, the present invention has the following technical effects:

[0023] (I) The design method of the reverse lip structure combined oil seal of the present invention can realize that one lip seals the oil medium and the other lip resists foreign matter and water medium. Compared with traditional oil seals, it can significantly improve the sealing ability against foreign matter and water medium and ensure the reliability of the inner oil sealing lip.

[0024] (II) In the present invention, the stress triangle distribution is opposite to that of the conventional design through the reverse design of lip II, thereby achieving a reverse pumping effect, that is, the medium in area C can be sealed to prevent it from entering area B, which can significantly improve the ability to resist foreign matter in the outside world (area C) and ensure the sealing performance of lip I.

[0025] (III) The outer ring of the combined oil seal designed in the present invention forms a static seal with the mounting hole, and the inner lip forms a dynamic seal with the shaft. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a schematic diagram of the structure of a conventional oil seal.

[0027] Figure 2 Schematic diagram of the oil seal principle of a conventional oil seal structure.

[0028] Figure 3 Schematic diagram of the structure of a conventional combined oil seal in a comparative example.

[0029] Figure 4 It is a structural schematic diagram of the reverse lip structure combined oil seal provided in the present invention.

[0030] The meanings of the numbers in the figure are: 1-rotating shaft, 2-lip No. I, 3-lip No. II, 4-skeleton No. II, 5-rubber sealing body No. II, 6-skeleton No. I, 7-rubber sealing body No. I, 8-spring.

[0031] The specific contents of the present invention are further explained in detail below with reference to the embodiments. DETAILED DESCRIPTION

[0032] It should be noted that, unless otherwise specified, all components in the present invention are components known in the prior art.

[0033] Specific embodiments of the present invention are given below. It should be noted that the present invention is not limited to the following specific embodiments, and all equivalent changes made on the basis of the technical solution of this application fall within the protection scope of the present invention.

[0034] Comparative Example:

[0035] This comparative example provides a combined oil seal, such as Figure 3 As shown, lip No. I 2 adopts a conventional structural design, with the front side area A being the oil side and area B being the air side. Lip No. II 3 also adopts a conventional structural design, with the front side area B being the oil side and area C being the air side. In the combined oil seal design, lip No. I 2 plays the role of sealing the oil medium, and lip No. II 3 plays the role of resisting foreign matter. However, since the conventional structural design is still adopted, the large-particle dust-proofing effect is achieved only by relying on the interference fit of the rubber. If there is a small amount of dust and water medium, the dynamic pumping action of the lip will suck the dust, foreign matter and water medium on the outside (area C) into the inside (area B), which will affect the sealing function of lip I and cause the sealing failure of the overall structure.

[0036] Example:

[0037] This embodiment provides a reverse lip structure combined oil seal, such as Figure 4As shown, it includes a No. 1 lip 2 capable of contacting and sealing with the rotating shaft 1, the oil side angle α1 is formed between the front lip of the No. 1 lip 2 and the rotating shaft 1, and the air side angle β1 is formed between the rear lip of the No. 1 lip 2 and the rotating shaft 1, and is characterized in that:

[0038] It also includes a No. II lip 3 capable of contacting and sealing with the rotating shaft 1. The No. II lip 3 is located at the rear side of the No. I lip 2. The front lip of the No. II lip 3 is arranged opposite to the rear lip of the No. I lip 2.

[0039] like Figure 4 As shown, the air side angle β' is formed between the front lip of lip No. II 3 and the rotating shaft 1, and the oil side angle α' is formed between the rear lip of lip No. I 2 and the rotating shaft 1, so that lip No. I 2 and lip No. II 3 form a reverse lip structure.

[0040] As a further solution of this embodiment, Figure 4 As shown, the oil side angle α1>the air side angle β1, and the oil side angle α'>the air side angle β'.

[0041] As a preferred solution of this embodiment, α1=40-50°, β1=17-25°, R1=0.2-0.7; α'=40-50°, β'=17-25°, R'=0.2-0.7;

[0042] in:

[0043] R is the spring offset of lip No. I;

[0044] R' is the spring deflection of lip II.

[0045] As a further solution of this embodiment, Figure 4 As shown, α1=α'; β 1＝ β'; R' = -R, where - represents the reverse direction.

[0046] In this embodiment, Figure 4 As shown in the figure, the oil side angle α1, air side angle β1, and spring offset R of lip No. 1 2 are designed in a forward direction, that is, the oil side angle α1>air side angle β1, and the center of the spring is on the rear side of lip No. 1 2, that is, the spring β1 side (air side / B area side) ensures the oil medium sealing in area A.

[0047] In this embodiment, Figure 4 As shown, the oil side angle α', air side angle β' and spring offset R' of lip No. II 3 are designed in reverse, that is, the oil side angle α'>air side angle β', and the center of the spring is on the front side of lip No. II 3, that is, the center of the spring is on the β' side (air side / B area side). In this way, the medium sealing ability of area C of lip No. II 3 can be achieved to prevent foreign matter and water medium from entering area B.

[0048] In this embodiment, Figure 4 As shown, lip No. I is arranged in front of lip No. II to ensure the oil medium sealing function of the front side A area.

[0049] As a preferred solution of this embodiment, Figure 4 As shown, lip 2 (I) and lip 3 (II) are wedge-shaped. Lip 3 (II) is the outer lip, primarily designed to resist foreign matter and seal water. It still uses the wedge-shaped design. The front and rear corners of the rubber distribute the sealing stress, while a spring provides additional preload. A rubber auxiliary lip is added to the outermost (rear) side.

[0050] As a further solution of this embodiment, Figure 4 As shown, it also includes a frame II 4, on which a rubber seal 5 is mounted, and a lip II 3 is provided on the rubber seal 5. The overall frame II 4 of the oil seal structure of this embodiment is supported to ensure the overall frame structure of the oil seal.

[0051] As a preferred solution of this embodiment, Figure 4 As shown, the II frame 4 and the mounting hole of the II frame 4 are statically sealed by using rubber with interference fit. Preferably, the interference fit is 0.15 to 0.55.

[0052] As a further solution of this embodiment, Figure 4 As shown, it also includes a No. 1 frame 6, on which a No. 1 rubber seal 7 is installed, and on which a No. 1 lip 2 is provided. In this embodiment, the No. 1 frame 6 plays the role of maintaining the overall framework of the No. 1 lip 2.

[0053] As a preferred solution of this embodiment, Figure 4 As shown, the frame I 6 is connected to the frame II 4 by means of interference fit through rubber, so that a static seal is achieved between the frame I 6 and the frame II 4. Preferably, the interference fit is 0.15 to 0.55.

[0054] In this embodiment, Figure 4 As shown, the stress triangle formed by lip No. 1 2 realizes the dynamic sealing of the oil medium in area A, the interference fit of the outer ring rubber of skeleton No. 1 6 realizes the static sealing between areas A and B, the stress triangle formed by lip No. 2 3 realizes the sealing of foreign matter and water medium in area C, and the interference fit of the outer ring rubber of skeleton No. 2 5 forms the static sealing between areas A and C, realizing the oil medium sealing function in area A and the foreign matter and water medium sealing function in area C as a whole.

[0055] In this embodiment, Figure 4As shown in the figure, from the stress distribution of lip 3 No. II, a wedge-shaped stress distribution is formed when the oil seal lip contacts the shaft. Due to the existence of the oil side angle α' and the air side angle β' on both sides, pumping toward the center is formed. However, the stress distribution center is biased toward the oil side angle α', and the net pumping is from the air side angle β' to the oil side angle α', thus achieving the medium sealing effect in area C.

[0056] Performance comparison test:

[0057] To further compare and verify the effectiveness of the present invention, a mud test was designed, subjecting area C to continuous mud splashing. The conventional structured combined oil seal described in the comparative example could withstand mud leakage into area A for only 40 hours, while the reverse lip structured combined oil seal described in the embodiments of the present invention could withstand at least 480 hours of mud testing, far outperforming the conventional structure. Therefore, the reverse lip structured combined oil seal of the present invention significantly improves its resistance to dust and aqueous media compared to the conventional combined oil seal in the comparative example, addressing the problem of oil seal lip failure caused by the ingress of dust and foreign matter in actual use.

Claims

1. A combined oil seal with a reverse lip structure, comprising a No. 1 lip (2) capable of contacting and sealing with a rotating shaft (1), wherein the front lip of the No. 1 lip (2) forms an oil-side angle α1 with the rotating shaft (1), and the rear lip of the No. 1 lip (2) forms an air-side angle β1 with the rotating shaft (1), and is characterized in that: It also includes a No. II lip (3) capable of contacting and sealing with the rotating shaft (1), the No. II lip (3) being located at the rear side of the No. I lip (2), and the front lip of the No. II lip (3) being arranged opposite to the rear lip of the No. I lip (2); The front lip of the No. II lip (3) forms an air side angle β' with the rotation axis (1), and the rear lip of the No. I lip (2) forms an oil side angle α' with the rotation axis (1), so that the No. I lip (2) and the No. II lip (3) form a reverse lip structure.

2. The reverse lip structure combined oil seal according to claim 1, characterized in that: The oil side angle α1>the air side angle β1, and the oil side angle α'>the air side angle β'.

3. The reverse lip structure combined oil seal according to claim 2, characterized in that: α1=40~50°, β1=17~25°, R1=0.2~0.7; α'=40~50°, β'=17~25°, R'=0.2~0.7; in: R is the spring offset of lip No. I; R' is the spring deflection of lip II.

4. The reverse lip structure combined oil seal according to claim 2, characterized in that: α1=α';β 1＝ β'; R' = -R, where - represents the reverse direction.

5. The reverse lip structure combined oil seal according to claim 1, characterized in that: The No. I lip (2) adopts a wedge-shaped lip; the No. II lip (3) adopts a wedge-shaped lip.

6. The reverse lip structure combined oil seal according to claim 1, characterized in that: It also includes a No. II frame (4), a No. II rubber sealing body (5) is installed on the No. II frame (4), and a No. II lip (3) is provided on the No. II rubber sealing body (5).

7. The reverse lip structure combined oil seal according to claim 6, characterized in that: Static sealing is achieved between the No. II frame (4) and the mounting hole of the No. II frame (4) by using interference fit with rubber.

8. The reverse lip structure combined oil seal according to claim 6, characterized in that: It also includes a No. 1 frame (6), a No. 1 rubber sealing body (7) is installed on the No. 1 frame (6), and a No. 1 lip (2) is provided on the No. 1 rubber sealing body (7).

9. The reverse lip structure combined oil seal according to claim 8, characterized in that: The No. I frame (6) is connected to the No. II frame (4) through rubber by an interference fit, so that a static seal is achieved between the No. I frame (6) and the No. II frame (4).

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