Oil seal sealing element

Abstract

The invention discloses an oil seal sealing piece, and relates to the technical field of hydraulic hammer sealing, the oil seal sealing piece comprises an injection molding piece, the injection molding piece comprises a first inner ring face and a first inner side face, the inner ring face is provided with an auxiliary lip, the auxiliary lip comprises a second inner ring face, a second inner side face and a second outer side face, the second inner ring face is of an arc-shaped structure, and the second inner side face is of an arc-shaped structure. A thin blade is arranged at the joint of the side edge of the second inner ring surface and the second inner side surface as well as the second outer side surface; and a polyhedral concave groove is formed in the first inner side surface. On the basis of a thin blade structure, a collaborative design of low-pressure sealing and low-temperature flexibility enhancement of the polyhedral sunken grooves is preferably established, and reliable sealing and long-acting durability of the main lip and the auxiliary lip under the working conditions of being smaller than 5 MPa and being smaller than 50-60 DEG C are achieved.

Description

Technical Field

[0001] The invention relates to a hydraulic hammer sealing technology, in particular to an oil seal. Background Art

[0002] The sealing system of hydraulic hammers (such as breakers and pile drivers) is a core component that directly determines the equipment's operating efficiency, lifespan, and reliability. These seals must withstand harsh operating conditions such as high-frequency shock, extreme pressure fluctuations, severe vibration, dust contamination, and wide temperature fluctuations.

[0003] For example, a Chinese patent, publication number: CN111608986A, publication date: 2020-09-01, discloses a cylinder sealing structure in a hydraulic breaker.

[0004] Another example is a Chinese patent, publication number CN106660199A, published on May 10, 2017, which discloses a hydraulic hammer with a single-piece sealing assembly.

[0005] In the existing technologies, including the aforementioned patents, there are generally deficiencies in the sealing reliability issues under low-pressure (<5MPa) and low-temperature (<50~60°C) working conditions. When the high-speed reciprocating motion of the piston generates local high temperatures (>120°C), the existing solutions can easily cause the polyurethane sealing ring to undergo thermal softening and deformation, and the resilience of the sealing lip decreases. Continuous heat loads can also cause the material's cross-linking degree to decrease and the molecular chains to break, resulting in permanent compression deformation of the sealing surface. At the same time, the high-pressure peak (35MPa+) under piston movement creates a high-frequency hydraulic shock wave, exacerbating the propagation of microcracks at the root of the sealing ring. However, the existing technologies fail to provide an effective solution to the problem of potential failure of the main sealing lip under non-extreme but critical basic working conditions such as low-pressure startup or low-temperature operation. Summary of the Invention

[0006] The object of the present invention is to provide an oil seal to solve the above-mentioned deficiencies in the prior art.

[0007] In order to achieve the above object, the present invention provides the following technical solution: an oil seal, comprising an injection molded part, which includes a first inner ring surface and a first inner side surface, wherein:

[0008] The inner ring surface is provided with an attachment lip, which includes a second inner ring surface, a second inner side surface and a second outer side surface. The second inner ring surface is an arc-shaped structure, and the junction between the side edge of the second inner ring surface and the second inner side surface and the second outer side surface is a thin blade;

[0009] A polyhedral recessed groove is provided on the first inner side surface.

[0010] Preferably, the injection molded part includes a first outer side surface, and the side surface of the attached lip is flush with the first outer side surface.

[0011] Preferably, the axial length of the attachment lip is one-half of the axial length of the injection molded part.

[0012] Preferably, there are two thin blades, and the two are distributed on the same horizontal plane.

[0013] Preferably, the number of the thin blades is two, and the horizontal plane formed by the line connecting the vertices of the two is an inclined plane, and the angle between the inclined plane and the first inner ring surface is an acute angle;

[0014] And located below the inclined surface, one thin blade is a low-position thin blade, and the other thin blade is a high-position thin blade, and the high-position thin blade is distributed adjacent to the first outer side surface.

[0015] Preferably, the thin blade is divided into a first inclined portion, a horizontal portion and a second inclined portion according to the structure;

[0016] a horizontal portion of a thin edge adjacent to the first outer side surface is higher than a horizontal portion of a thin edge adjacent to the first inner side surface;

[0017] The ends of the two second inclined portions are connected by a U-shaped portion;

[0018] The first inclined portion of the thin blade adjacent to the first inner side surface is the second inner side surface;

[0019] The first inclined portion of a thin edge adjacent to the first outer side surface is the second outer side surface.

[0020] Preferably, a third inclined portion is provided on the side surface of the first inner side surface, the third inclined portion is symmetrically distributed with the first inclined portion, and has the same inclined direction, and the third inclined portion, the first inclined portion and the first inner side surface form a polyhedral recessed groove.

[0021] Preferably, the circumferential diameter of the attached lip is smaller than the circumferential diameter of the first inner ring surface.

[0022] Preferably, the polyhedral recessed groove has at least two side edges, and the junction of the two side edges is an arc angle.

[0023] Preferably, the two side edges are of the same length.

[0024] Preferably, the arc angle is centrally distributed on the first inner side surface.

[0025] Preferably, the injection molded part is in a ring shape.

[0026] In the above-mentioned technical solution, the present invention provides an oil seal with the following beneficial effects: The thin blade structure on the auxiliary lip, particularly its curved second inner ring surface, preferentially forms an effective contact seal with the piston rod under low pressure (<5MPa) and low temperature (<50-60°C) operating conditions. The thin blade design significantly reduces the contact area and frictional resistance, thereby reducing frictional heat generation. Secondly, the polyhedral recessed groove with rounded corners on the first inner side surface significantly enhances the flexibility of the seal body, particularly the auxiliary lip area. This enhanced flexibility is particularly critical in low-temperature environments, as it effectively compensates for the increased material stiffness caused by low temperatures, ensuring that the auxiliary lip maintains a tight fit on the piston rod surface at low temperatures and preventing low-temperature leakage. Furthermore, the increased heat dissipation surface area helps disperse thermal stress in higher temperature environments, slowing material aging and ensuring the sealing reliability and durability of the primary and secondary lips throughout the entire operating temperature range. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments described in the present invention. For ordinary technicians in this field, other drawings can also be obtained based on these drawings.

[0028] Figure 1 A schematic diagram of the overall structure provided by an embodiment of the present invention;

[0029] Figure 2 A schematic structural diagram of a first outer side surface provided by an embodiment of the present invention;

[0030] Figure 3 A schematic structural diagram of a first embodiment of the present invention;

[0031] Figure 4 A schematic structural diagram of a second embodiment of the present invention;

[0032] Figure 5 A schematic structural diagram of a third embodiment of the present invention.

[0033] Description of reference numerals:

[0034] 1. Injection molded part; 11. First inner ring surface; 12. First inner side surface; 121. Third inclined portion; 13. First outer side surface; 2. Attached lip; 21. Second inner ring surface; 22. Second inner side surface; 23. Second outer side surface; 3. Thin blade; 31. First inclined portion; 32. Horizontal portion; 33. Second inclined portion; 34. U-shaped portion; 4. Polyhedral recessed groove; 41. Arc angle. DETAILED DESCRIPTION

[0035] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings.

[0036] See also Figure 1-2 The embodiment of the present invention provides a technical solution: an oil seal, comprising an injection molded part 1 (annular), comprising a first inner ring surface 11 and a first inner side surface 12, wherein:

[0037] An attachment lip 2 is provided on the inner ring surface 11. The attachment lip 2 includes a second inner ring surface 21, a second inner side surface 22, and a second outer side surface 23. The second inner ring surface 21 is an arc-shaped structure. A thin blade 3 is formed at the junction of the side edge of the second inner ring surface 21, the second inner side surface 22, and the second outer side surface 23.

[0038] A polyhedral recessed groove 4 is defined on the first inner side surface 12 .

[0039] Specifically, the injection molded part 1 can be made of polyurethane PPDI, MDI, TDI, etc., or can be made of rubber FKM or HNBR.

[0040] The thin blade 3 structure on the auxiliary lip 2 in the above-mentioned technology, particularly its curved second inner ring surface 22, preferentially forms an effective contact seal with the piston rod under low-pressure (<5MPa) and low-temperature (<50-60°C) operating conditions. This thin blade design significantly reduces contact area and frictional resistance, thereby reducing frictional heat generation. Secondly, the polyhedral recessed groove with rounded corners designed on the first inner side surface 12 significantly enhances the flexibility of the seal body, particularly the auxiliary lip area. This enhanced flexibility is particularly critical in low-temperature environments, effectively compensating for the increased material rigidity caused by low temperatures, ensuring that the auxiliary lip 2 maintains a tight fit on the piston rod surface at low temperatures and preventing low-temperature leakage. Furthermore, the increased heat dissipation surface area helps disperse thermal stress in higher-temperature environments, slowing material aging and ultimately ensuring the sealing reliability and durability of the primary and secondary lips throughout the entire operating temperature range.

[0041] The thin blade 3 itself has better compliance and deformation ability, and can more effectively absorb and buffer the energy of high-frequency hydraulic shock waves, reducing the impact damage to the sealing ring base.

[0042] As a further embodiment provided by the present invention, the molded part 1 includes a first outer side surface 13, and the side surface of the attachment lip 2 is flush with the first outer side surface 13. Furthermore, the axial length of the attachment lip 2 is one-half the axial length of the molded part 1. Furthermore, the circumferential diameter of the attachment lip 2 is smaller than the circumferential diameter of the first inner ring surface 11.

[0043] There is a certain height difference between the second inner ring surface 21 of the attachment lip 2 and the first inner ring surface 11 of the injection molded part 1 , thereby forming a step design.

[0044] Furthermore, the side surface of the attached lip 2 is flush with the first outer side surface 13, has a moderate axial length, and a circumferential diameter smaller than the first inner ring surface 11. These designs ensure that the attached lip has sufficient support rigidity and stability to avoid excessive distortion or instability under high pressure and impact, while maintaining the necessary flexibility, thereby enhancing the overall structural strength and damage resistance.

[0045] As another embodiment further provided by the present invention, Figure 3 As shown, there are two thin blades 3, and the two are distributed in the same horizontal plane.

[0046] The thin blade 3 provided on the aforementioned auxiliary lip 2, especially the arcuate second inner ring surface 21 and the thin blade structure, significantly reduces the contact area and friction resistance between the sealing lip and the moving piston rod.

[0047] As another embodiment further provided by the present invention, Figure 4 As shown, there are two thin blades 3, and the horizontal plane formed by the line connecting the two vertices is an inclined plane, and the angle between the inclined plane and the first inner ring surface 11 is an acute angle. Moreover, below the inclined plane, one thin blade 3 is a low-position thin blade, while the other thin blade 3 is a high-position thin blade, and the high-position thin blade is distributed adjacent to the first outer side surface 13.

[0048] The line connecting the vertices of the two thin blades 3 forms an inclined plane, forming a low thin blade and a high thin blade, with the high thin blade adjacent to the first outer side surface 13. This asymmetric stepped layout creates a pressure gradient seal under high-pressure conditions (>35MPa). The high thin blade first withstands and buffers some of the extreme pressure peak, while the low thin blade provides secondary sealing, effectively dispersing the extremely high hydraulic shock load borne by the single sealing lip and significantly reducing stress concentration in the root area.

[0049] As another embodiment further provided by the present invention, the polyhedral recessed groove 4 has at least two side edges, and the junction of the two side edges is an arc corner 41 .

[0050] Furthermore, the lengths of the two sides are the same.

[0051] Secondly, the arc corner 41 is centrally distributed on the first inner side surface 12 .

[0052] The key feature of this technology is the rounded corners 41 at the juncture of the sides of the polyhedral recessed groove 4. They eliminate sharp stress concentration points and significantly improve stress distribution at the groove root. This directly inhibits the initiation of microcracks under high-pressure hydraulic shock and alternating stresses, and effectively hinders the propagation of existing microcracks, particularly those originating at the root. This significantly improves the seal's fatigue resistance and long-term sealing reliability under harsh dynamic operating conditions.

[0053] In summary, the above structures work together to reduce frictional heat generation (thin blades) and enhance heat dissipation / thermal aging resistance (polyhedral recessed grooves 4), stabilizing material properties. Distributing pressure loads (the high and low positions of the two thin blades 3) and eliminating stress concentration (recessed groove arc angles 41) work together to effectively resist high-pressure shocks and suppress cracking. The optimal structure (size and position) of the lip 2 provides stable support for the thin blades. This multi-layered, coordinated design ensures the seal maintains excellent dynamic sealing performance over time even at high reciprocating speeds, effectively resolving the key issue of increasing leakage over time, as discussed in the background.

[0054] As another embodiment further provided by the present invention, Figure 5 As shown, the thin blade 3 is divided into a first inclined portion 31, a horizontal portion 32 and a second inclined portion 33 according to the structure;

[0055] The horizontal portion 32 of one thin edge 3 adjacent to the first outer side surface 13 is higher than the horizontal portion 32 of one thin edge 3 adjacent to the first inner side surface 12;

[0056] The ends of the two second inclined portions 33 are connected by a U-shaped portion 34;

[0057] The first inclined portion 31 of a thin edge 3 adjacent to the first inner side surface 12 is the second inner side surface 22;

[0058] The first inclined portion 31 of one thin edge 3 adjacent to the first outer side surface 13 serves as the second outer side surface 23 .

[0059] Furthermore, a third inclined portion 121 is provided on the side of the first inner side surface 12 . The third inclined portion 121 is symmetrically distributed with the first inclined portion 31 and has the same inclined direction. The third inclined portion 121 , the first inclined portion 31 and the first inner side surface 12 form a polyhedral recessed groove 4 .

[0060] Specifically, the above-mentioned thin blade 3 is a polyhedral structure, and has two surfaces in contact with the piston. While greatly reducing the contact surface, two sealing environments are set up, and the liquid oil passing through the first layer will enter the U-shaped part 34, thereby preventing the oil from escaping from the second sealed thin blade 3.

[0061] The above description is merely illustrative of certain exemplary embodiments of the present invention. It goes without saying that those skilled in the art will be able to modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the above drawings and description are illustrative in nature and should not be construed as limiting the scope of protection of the claims.

Claims

1. An oil seal, characterized in that: An injection molded part (1) includes a first inner ring surface (11) and a first inner side surface (12), wherein: The inner ring surface (11) is provided with an attached lip (2), the attached lip (2) comprising a second inner ring surface (21), a second inner side surface (22) and a second outer side surface (23), the second inner ring surface (21) being an arc-shaped structure, and a thin blade (3) forming a junction between the side edge of the second inner ring surface (21), the second inner side surface (22) and the second outer side surface (23); A polyhedral recessed groove (4) is provided on the first inner side surface (12).

2. The oil seal according to claim 1, characterized in that: The injection molded part (1) comprises a first outer side surface (13), and the side surface of the attached lip (2) is flush with the first outer side surface (13).

3. The oil seal according to claim 1, characterized in that: The axial length of the attached lip (2) is one-half of the axial length of the injection molded part (1).

4. The oil seal according to claim 2, characterized in that: There are two thin blades (3), and the two are distributed on the same horizontal plane.

5. The oil seal according to claim 2, characterized in that: The number of the thin blades (3) is two, and the horizontal plane formed by the line connecting the vertices of the two is an inclined plane, and the angle between the inclined plane and the first inner ring surface (11) is an acute angle; Located below the inclined surface, one thin blade (3) is a low-position thin blade, while the other thin blade (3) is a high-position thin blade, and the high-position thin blade is distributed adjacent to the first outer side surface (13).

6. The oil seal according to claim 2, characterized in that: The thin blade (3) is divided into a first inclined portion (31), a horizontal portion (32), and a second inclined portion (33) according to its structure; A horizontal portion (32) of a thin blade (3) adjacent to the first outer side surface (13) is higher than a horizontal portion (32) of a thin blade (3) adjacent to the first inner side surface (12); The ends of the two second inclined portions (33) are connected via a U-shaped portion (34); The first inclined portion (31) of a thin blade (3) adjacent to the first inner side surface (12) is a second inner side surface (22); The first inclined portion (31) of a thin edge (3) adjacent to the first outer side surface (13) is the second outer side surface (23).

7. The oil seal according to claim 2, characterized in that: A third inclined portion (121) is provided on the side of the first inner side surface (12); the third inclined portion (121) and the first inclined portion (31) are symmetrically distributed and have the same inclined direction; and the third inclined portion (121), the first inclined portion (31) and the first inner side surface (12) form a polyhedral recessed groove (4).

8. The oil seal according to claim 1, characterized in that: The circumferential diameter of the attached lip (2) is smaller than the circumferential diameter of the first inner ring surface (11).

9. The oil seal according to claim 1, characterized in that: The polyhedral recessed groove (4) has at least two side edges, and the junction of the two side edges is an arc angle (41), and the lengths of the two side edges are consistent.

10. The oil seal according to claim 9, characterized in that: The arc angle (41) is centrally distributed on the first inner side surface (12).

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