V-ring for a V-ring seal kit

Abstract

V-ring (4, 4') for a V-ring seal set (1, 1') for sealing between two components (2, 3) moving relative to one another in the axial direction (A), wherein the V-ring (4, 4') has two legs extending from one another in a V-shape, wherein one leg has a sealing lip (13) which is provided for contact with the component (3) moving relative to the V-ring (4, 4') in the axial direction (A) of the two components (2, 3) moving relative to one another in the axial direction, wherein a first, low-pressure side sealing surface (11) extends from the sealing lip (13) at a first angle (α1) to the ring axis (A) and a second, high-pressure side sealing surface (12) extends at a second angle (α2) to the ring axis (A), wherein the first and the second angle are each greater than 0° and less than 90° and wherein the first angle (α1) is less than the second angle (α2).

Description

[0001] The present invention relates to a V-ring and a pressure ring for a V-ring seal set according to the preambles of the independent patent claims and to a V-ring seal set. State of the art

[0002] A non-modular sealing arrangement for sealing a rod-shaped element against a substantially cylindrical pipe is known, for example, from DE 199 38 785 A1.

[0003] To seal against axial relative movement between two components, such as between a piston rod and a cylinder or bearing in hydraulic applications, so-called V-ring seal sets are often used, for example, as rod seals or piston seals. These consist of a thrust ring, one or more V-ring seals, and a backup ring. A generic V-ring seal set is described in DE 199 06 733 C2. In this context, reference is also made to DE 692 09 824 T2.

[0004] V-ring seal sets have the advantage of a modular design, which means they can be easily adapted to the prevailing pressure conditions by using more or fewer V-rings, and they are also easy to install, maintain, or replace. They also offer relatively good sealing. On the other hand, however, there is also a high level of friction between the moving component and the seal set, meaning a lot of resistance has to be overcome and wear is also relatively rapid. Particularly in hydraulics, where relatively large pressure differences have to be sealed and therefore often a large number of seals are required, there is a need for improved, particularly lower-friction, sealing options. Especially in heavy-duty hydraulics, the use of V-ring seal sets is hardly possible today because the resulting friction would be too great.As a result, other sealing concepts must be used, which, however, lack modularity. Disclosure of the invention

[0005] According to the invention, a V-ring and a pressure ring for a V-ring seal set, as well as a V-ring seal set, are proposed with the features of the independent patent claims. Advantageous embodiments are the subject of the subclaims and the following description.

[0006] The invention provides the aforementioned sealing rings for V-ring seal sets with a special geometry. During use, surfaces facing the moving component form specific angles with the direction of movement and thus with the component, so that hydrodynamic lubrication is achieved. At the same time, due to the geometry, the movement causes the fluid to be sealed to be pumped back from the low-pressure side to the high-pressure side. Overall, friction can thus be significantly reduced, while at the same time, tightness is hardly affected. As a result, wear and maintenance costs are also significantly reduced. The invention makes it possible, for example, to make V-ring seal sets suitable for use in heavy hydraulics without any disadvantages. The invention creates a seal between the moving components using a fluid film according to hydrodynamic lubrication.This fluid film, combined with the special asymmetric geometry of the sealing surfaces, enables fluid to be pumped back. The invention reduces friction and maintains the modular design and associated advantages of conventional V-ring seal sets.

[0007] The invention is based on the special design of the V-ring, in particular the sealing surfaces on the side facing the moving component, and on the special design of the thrust ring, in particular the side facing the moving component. The support ring for a V-ring sealing ring set according to the invention can be of conventional design. The thrust ring is preferably made entirely or partially of ultra-high molecular weight polyethylene (UHMWPE), and the V-ring is made of a thermoplastic elastomer, e.g., polyurethane (PUR). The support ring can be made of nitrile rubber (NBR).

[0008] A key advantage of asymmetric sealing profiles is that the hydrodynamic flow when the component moves in one direction differs from the hydrodynamic flow when the component moves in the other direction, resulting in effective back-pumping of the fluid to be sealed. When the component, such as the piston or piston rod, moves toward the high-pressure side, a relatively strong drag flow is generated. Conversely, when the component moves toward the low-pressure side, only a minimal fluid film is created. As a result, fluid is effectively pumped back to the high-pressure side, creating a strong sealing effect. This effect is enhanced by the number of sealing collar rings. The structural concept of the invention leads to improved friction and wear properties, allows for even large movements of the component, and is still easy to handle, manufacture, assemble, and maintain.

[0009] Further advantages and embodiments of the invention will become apparent from the description and the accompanying drawings.

[0010] It is understood that the features mentioned above and those to be explained below can be used not only in the combination specified in each case, but also in other combinations or on their own, without departing from the scope of the present invention.

[0011] The invention is illustrated schematically in the drawing using exemplary embodiments and is described in detail below with reference to the drawing. Character description Fig. 1 shows a first preferred embodiment of a V-ring seal set according to the invention in an axial sectional view in use as a rod seal between two components moving axially relative to each other. Fig. 2 shows a second preferred embodiment of a V-ring sealing ring set according to the invention in an axial sectional view in use as a rod seal between two components moving axially relative to each other. Fig. 3 shows a first preferred embodiment of a V-ring sealing ring according to the invention in an axial sectional view. Fig. 4 shows a second preferred embodiment of a V-ring sealing ring according to the invention in an axial sectional view. Fig. 5 shows a preferred embodiment of a pressure ring according to the invention in an axial sectional view.

[0012] The figures depict elements according to the invention in axial section and are described below in a coherent and comprehensive manner. Although the illustrated V-ring seal sets each comprise a pressure ring, three V-ring seals, and a backup ring, it should be expressly clarified that the invention also applies to a single backup ring and a single V-ring seal. Furthermore, the number of rings in a V-ring seal set depends on the intended use and can be selected accordingly by a person skilled in the art.

[0013] In Fig. Figure 1 shows a first preferred embodiment of a V-ring seal set according to the invention in an axial sectional view and is designated overall by 1. Such a V-ring seal set 1 is provided between a first component 3 moving along an axis A, which is also the ring axis (=axis of symmetry), and a second component 2 stationary relative to the V-ring seal set 1, in order to seal a fluid on a high-pressure side H from a low-pressure side N. In particular, a V-ring seal set is used in hydraulics as a rod seal or as a piston seal. The V-ring seal set 1 comprises a pressure ring 8, three V-rings 4 and a support ring 10. The pressure ring closes off the V-ring seal set on the low-pressure side, and the support ring closes off the high-pressure side.

[0014] The second preferred embodiment 1' according to Fig. 2 differs from the first preferred embodiment 1 according to Fig. 1 by a different geometry of the V-ring sealing rings 4'.

[0015] In the following, the geometry of a preferred V-ring sealing ring 4, 4' will be explained in more detail, which is described in detail in Fig. 3 or Fig. 4. The V-ring 4 is preferably made of an elastomer, in particular PUR, and is generally annular, having a V-shaped profile in axial section.

[0016] The sealing side facing the moving component 3, which in the configuration designed here as a rod seal simultaneously describes an inner circumference of the V-ring sealing ring 4, is designated by 5. The design of the sealing side 5 is essentially defined by two sealing surfaces 11 and 12 extending from a sealing lip 13. The sealing surfaces 11 and 12 each enclose different angles with the component 3, here an angle a1 and an angle a2 respectively. The first, low-pressure side sealing surface 11 encloses the first angle a1 with the component 3 or the axis A, and the second, high-pressure side sealing surface 12 encloses the second angle a2 with the component 3 or the axis A. The sealing lip 13 forms the connection between the first and the second sealing surface and can in particular have a fillet radius. The fillet radius can, for example, be between 0 and 0.8 mm.

[0017] The first, low-pressure-side sealing surface 11 is oriented toward another V-ring sealing ring or toward the support ring. The first angle a1 is preferably between 15 and 25 degrees. The second, high-pressure-side sealing surface 12 is oriented toward another V-ring sealing ring or toward the support ring. The second angle a2 is preferably between 30 and 40 degrees. The high-pressure-side sealing surface 12 is essentially straight in profile; the low-pressure-side sealing surface 11 can be curved in profile (cf. Fig. 1 and Fig. 3) or straight (cf. Fig. 2 and Fig. 4) be.

[0018] Opposite the sealing side 5 is a third sealing surface 17, which serves to seal against the stationary component 2. The third sealing surface 17 preferably forms a third angle a3 of 2 to 8 degrees with the second component 2 or the axis A. Adjacent to the third sealing surface 17 on the high-pressure side is a sealing surface 18, which preferably forms an angle of approximately 90 degrees with the axis A.

[0019] The V-ring seal 4, 4' further has three low-pressure-side surfaces 14, 15, and 16 that connect the seal sides 5 and 17 on the low-pressure side and are referred to below as support surfaces. The support surfaces 14 and 16 preferably form an angle of 40 to 45 degrees with the axis A, preferably the same angle. The support surface 15 is straight and preferably perpendicular to the axis A.

[0020] On the high-pressure side, there are corresponding support surfaces 19, 20, and 21, wherein the support surfaces 19 and 21 also preferably form an angle of 40 to 45 degrees with the axis A, more preferably the same angle. The support surface 20 can be curved (as present) or straight (not shown).

[0021] The V-ring sealing ring set 1 further comprises a preferred pressure ring 8, which is described in detail in Fig.5 is shown. The thrust ring 8 is also annular and has a substantially rectangular profile in axial section with a trapezoidal indentation on the high-pressure side for receiving a V-ring. The thrust ring has a sealing side 9 which faces the moving component 3 and, in the configuration shown here as a rod seal, simultaneously describes an inner circumference of the thrust ring 8. The sealing side 9 is characterized by two sealing surfaces 22 and 23, with the fourth sealing surface 22 running parallel to the moving component 3 or to axis A. On the low-pressure side, the fourth sealing surface 22 is adjoined by the fifth sealing surface 23, which preferably encloses a fourth angle a4 of 1 to 8 degrees with the component 3 or the axis A. The sealing surfaces 22 and 23 are substantially linear in profile.A fillet radius, preferably between 0 and 0.3 mm, can be provided.

[0022] The fifth sealing surface 23 is followed on the low-pressure side by a sealing surface 24 which serves as an anti-extrusion surface and forms an angle of 40 to 50 degrees, preferably 45 degrees, with the axis A or the component 3.

[0023] Adjacent to the sealing surface 24 is a surface 25, referred to as the pressure support surface, which closes off the pressure ring 8 and the V-ring sealing ring set 1 on the low-pressure side. The pressure support surface 25 is perpendicular to the axis A.

[0024] From the pressure support surface 25, a surface 26 extends on the high-pressure side at an angle of 90 degrees and thus parallel to the axis A, which describes an outer circumference of the pressure ring 8.

[0025] On the high-pressure side, the thrust ring is provided with support surfaces 28, 29, and 30, which correspond in shape and function to the previously described support surfaces 19, 20, and 21 of the V-ring and define the aforementioned trapezoidal indentation. The support surfaces 28 and 30 are connected to the outer and inner circumferential surfaces 26 and 9, respectively, via sealing surfaces 27 and 31 perpendicular to the axis A.

[0026] The support ring 10 is designed as a conventional support ring.

[0027] The outer dimensions of the V-ring seal set 1, 1', as well as the inner dimensions of the cylinder 2 and the outer dimensions of the piston rod 3, are dimensioned such that, when stationary and without pressure, minimal compression or preload is present in the V-ring seal set 1, 1' to achieve static sealing. In the figures, the individual elements are shown in a non-preloaded and non-pressurized state, as only then can the axial cross-sectional profiles be clearly seen.

[0028] The compression of the V-ring seal set 1, 1' and the configuration of the sealing surfaces 11 and 12 generate a predetermined contact pressure profile, pressing the V-ring seal set against the outer surface of the piston 3. The V-ring seal set experiences maximum contact pressure in the area of ​​the sealing lip 13. From there, the pressure decreases continuously on both sides, with the gradient of the contact pressure decrease being directly linked to the size of the angles a1 and a2 of the associated sealing surfaces 11 and 12.

[0029] This results in the sealing surface with the larger angle having a greater gradient in the contact pressure gradient than the sealing surface with the smaller angle. These different gradients, together with the movement of component 3 in the high-pressure direction, lead to a relatively large drag flow. Previously leaked fluid can thus be pumped back. The magnitude of the drag flow can be adjusted by the first angle a1 on the low-pressure side sealing surface 11.

[0030] The different gradients, together with the movement of component 3 in the low-pressure direction, create a relatively thin fluid film, which ensures sufficient lubrication. The thickness of the fluid film can be adjusted by the second angle α2 at the high-pressure side sealing surface 12 and the fillet radius of the sealing lip 13.

[0031] The geometry of the sealing surfaces 11, 12 and 13 of the V-ring seal 4, 4' is selected such that, with increasing high pressure, the asymmetric pressure profile with which the V-ring seal set is pressed against the component 3 is maintained, which provides the functionality of the asymmetric pressure profile, namely fluid film control and a sufficient back pumping effect.

[0032] It should be made clear that the angles described in connection with the illustrated embodiments independently represent specific developments of the invention. The limits of the described angle ranges lie within these ranges.

Claims

[1] V-ring (4, 4') for a V-ring seal set (1, 1') for sealing between two components (2, 3) moving relative to one another in the axial direction (A), wherein the V-ring (4, 4') has two legs extending from one another in a V-shape, wherein one leg has a sealing lip (13) which is provided for contact with the component (3) moving relative to the V-ring (4, 4') in the axial direction (A) of the two components (2, 3) moving relative to one another in the axial direction, wherein a first, low-pressure side sealing surface (11) extends from the sealing lip (13) at a first angle (α1) to the ring axis (A) and a second, high-pressure side sealing surface (12) extends at a second angle (α2) to the ring axis (A), wherein the first and the second angle are each greater than 0° and less than 90° and wherein the first angle (α1) is less than the second angle (α2). [2] V-ring (4, 4') according to claim 1, wherein the first and second angles (α1, α2) are each greater than 10° and / or less than 45°. [3] V-ring (4, 4') according to claim 1 or 2, wherein the first angle (α1) is in a range of 15° to 25°. [4] V-ring (4, 4') according to one of the preceding claims, wherein the second angle (α2) is in a range of 30° to 40°. [5] V-ring (4, 4') according to one of the preceding claims, wherein the first, low-pressure side sealing surface (11) is straight or curved in profile. [6] V-ring (4, 4') according to one of the preceding claims, wherein the other leg has a third sealing surface (17) which is provided for contact with the component (2) which does not move in the axial direction (A) relative to the V-ring (4, 4') of the two components (2, 3) which move relative to one another in the axial direction, wherein the third sealing surface (17) encloses a third angle (α3) greater than 0° with the ring axis (A). [7] V-ring (4, 4') according to claim 6, wherein the third angle (α3) is in a range of 2° to 8°. [8] Pressure ring (8) for a V-ring seal set (1, 1') for sealing between two components (2, 3) moving relative to one another in the axial direction (A), wherein the pressure ring (8) has a fourth sealing surface (22) which is provided for contact with the component (3) of the two components (2, 3) moving relative to one another in the axial direction (A) and which extends parallel to the ring axis (A), wherein a fifth, low-pressure side sealing surface (23) extends from the fourth sealing surface (22) at a fourth angle (α1) to the ring axis (A), wherein the fourth angle (α4) is greater than 0° and less than 45°, in particular less than 15°. [9] Pressure ring (8) according to claim 8, wherein the fourth angle (α4) is in a range of 1° to 8°. [10] Pressure ring (8) according to claim 8 or 9, wherein a sixth, low-pressure side sealing surface (24) extends from the fifth sealing surface (23) at a fifth angle (α5) to the ring axis (A), wherein the fifth angle (α5) lies in a range from 20° to 70°, in particular from 40° to 50°. [11] Pressure ring (8) according to claim 10, wherein the fifth angle (α5) is 45°. [12] V-ring sealing ring set (1, 1') comprising at least one V-ring sealing ring (4, 4') according to one of claims 1 to 7 and a pressure ring (8) according to one of claims 8 to 11.

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