WO2024248657A1 - Shaft seal and sealing ring for the implementation thereof (embodiments) - Google Patents

Abstract

The invention relates to the field of mechanical engineering and can be used for sealing cylindrical rotating surfaces. A shaft seal consists of a sealing ring mounted in a groove of a housing. The sealing ring is a resilient polymer ring with flat faces. Formed on the outside surface of the ring is a cylindrical ledge. Formed on the inside surface of the ring is a ledge with a hydrodynamic sealing surface, one of the faces of the ledge being flat and aligned with a face of the ring, and the other face of the ledge being wavy and having a rounded contour with a hydrodynamic sealing surface. The technical result consists in improving the operating efficiency of the shaft seal both by increasing the lifespan thereof and by ensuring the hermeticity of the seal throughout its working life.

Description

SHAFT SEAL AND SEAL RING FOR ITS IMPLEMENTATION (OPTIONS)

The invention relates to the field of mechanical engineering, in particular to sealing technology, and can be used for sealing cylindrical rotating surfaces.

A rotary seal of compression type with hydrodynamic lubrication is known, which is suitable for retaining lubricant and protecting against environmental influences. In particular, the geometry of the seal ensures the restriction of the hydrodynamic seal in such a way as to prevent wear caused by distortion, and provides sufficient space inside the gland to compensate for thermal expansion. The seal allows large deviations in the coefficient of thermal expansion of the sealing material during manufacture, provides a relatively rigid effect of the built-in spring to minimize pressure-induced movement of the seal inside the gland, and also maintains the interfacial contact pressure at the boundary of the dynamic seal in an optimal range for effective hydrodynamic lubrication and environmental protection (according to patent US6315302, cl. F16J 15/32, published 13.11.2001).

A composite dynamic seal is known, suitable for use in high-temperature conditions, which seal includes an elastic annular sealing body having a first layer formed from a first elastic sealing material, and a second layer formed from a second elastic sealing material. The first and second layers are preferably molded and cured together simultaneously and chemically crosslinked with each other. The first elastic sealing material is selected for its wear-resistant dynamic properties, and the second elastic sealing material is selected for its compression-resistant properties. Preferably, the first elastic sealing material is a copolymer of tetrafluoroethylene and propylene, and the second elastic sealing material is fluorocarbon rubber (according to patent US8075000, cl. F17J 15/32, published 13.12.2011). Known analogues have a similar design. The patents do not contain data on the geometric parameters of the dynamic sealing surface and edge, which directly affect the characteristics and performance of the seal.

The closest technical solution is a hydrodynamically lubricated seal, which is made in the form of a circular housing with a static sealing surface and a dynamic sealing lip projecting from the housing and having a dynamic sealing surface, a non-hydrodynamic lip and a non-circular inclined lip with a side angle. The side angle and the dynamic sealing surface have a theoretical intersection located from the non-hydrodynamic lip at a variable distance having a minimum size of at least 1/16 inch and a maximum size. The housing of the circular seal defines a theoretical center line, and when viewed in longitudinal cross-section taken along the theoretical center line, a hydrodynamic inlet curve is shown which combines the theoretical intersection between the side angle and the dynamic seal surface. This hydrodynamic inlet curve is tangent to the surface of the dynamic seal at the point of contact and has a degree of curvature less than the degree of curvature of the radius Y» inch. The number of waves of the dynamic sealing surface is less than the rounded result of its circumference divided by 1.1 inches. According to the embodiment, the radius of curvature of the dynamic sealing edge does not exceed 5/32 inches (according to patent US6382634, class F16J 15/32, published 07.05.2002).

The disadvantage of this design is that the dynamic sealing surface has a minimum size of at least 1/16 inch (-1.6 mm), the preferred range in the description is from 0.09 to 0.12 inches (2.29 to 3.05 mm), and the maximum size is specified as a ratio to the minimum size, which should be less than 1.8 and preferably less than 1.67. The specified intervals imply the implementation of seals with a very large difference in size (with a large value of the minimum size of the sealing surface and a ratio to the maximum of 1.8), and the implementation of a sealing surface with a straight edge (with a ratio of sizes of 1, which fits into the specified values). Whereas to obtain a reliable seals, it is necessary to ensure hydrodynamic wedging of the lubricating film between the seal and the rotating surface. It also follows from the formula and description of the known solution that the number of waves for shafts with a diameter of less than 17 mm will be equal to one, which will not ensure hydrodynamic wedging of the lubricating film. And for shafts with a diameter of less than 9 mm, the use of such seals is impossible.

The technical result, which the proposed invention is aimed at achieving, consists in increasing the efficiency of the shaft seal, which consists in increasing the service life and ensuring tightness throughout the entire service life.

The specified technical result is achieved in that the shaft seal consists of a sealing ring installed in a groove of the housing and representing an elastic polymer ring with flat end surfaces, a cylindrical protrusion is made on the outer cylindrical surface of the ring, a protrusion with a hydrodynamic sealing surface is made on the inner surface of the ring, one of the ends of which is made flat and coincides with the end surface of the ring, and the other end is made wavy with alternating peaks and valleys and having a rounding with a hydrodynamic sealing surface in contact with the shaft, and is characterized in that the diameter of the hydrodynamic sealing surface is equal to the diameter of the shaft, while the sealing ring is pressed against the shaft due to the fact that the diameter of the groove is less than the diameter of the cylindrical protrusion on the outer cylindrical surface of the sealing ring, while the wave height of the wave-shaped end of the sealing ring is made in the range from 1 to 2 mm, the wavelength of the wave-shaped end is made in the range from 10 to 30 mm, while the value of the circumference hydrodynamic sealing surface is a multiple of the wavelength, and the number of waves is not less than 2.

The technical result is also achieved by the fact that the shaft seal consists of a sealing ring installed in a groove in the housing and representing an elastic polymer ring with flat end surfaces, a cylindrical protrusion is made on the outer cylindrical surface of the ring, a protrusion with a hydrodynamic sealing surface in contact with the shaft is made on the inner surface of the ring, one of the ends of the protrusion is made flat and coincides with the end surface of the ring, and the other end is made wavy with alternating peaks and valleys, and is distinguished by the fact that the wavy end is formed by helical surfaces, evenly distributed around the circumference.

The technical result is also achieved by the fact that the shaft seal consists of a sealing ring installed in a groove in the housing and is an elastic polymer ring, on one end of which a groove is made in which a meander spring is installed, the inner part of the ring contacts the shaft and is made of plastic, and the outer part of the ring is made of elastomer, and is distinguished by the fact that on the inner surface of the ring there are uniformly distributed depressions in the form of inclined sectors around the circumference, emerging on the end opposite the groove.

The preferred compression of the sealing ring is provided in the range from 5 to 11%.

The shaft seal is implemented using a sealing ring, which is an elastic polymer ring with flat end surfaces, a cylindrical protrusion is made on the outer cylindrical surface of the ring, a protrusion with a hydrodynamic sealing surface is made on the inner surface of the ring, one of the ends of which is made flat and coincides with the end surface of the ring, and the other end is made wavy with alternating peaks and valleys and having a rounding with a hydrodynamic sealing surface, and is characterized in that the wave height of the wavy end is made in the range from 1 to 2 mm, the wavelength of the wavy end is made in the range from 10 to 30 mm, while the value of the circumference of the hydrodynamic sealing surface is a multiple of the wavelength, and the number of waves is at least 2.

In addition, the number of waves can be determined by the equation: y = 0.5N • cos(2n • x / d), where

H - wave height; n - number of waves; d - diameter of the hydrodynamic sealing surface.

In addition, the radius of rounding of the troughs of the wave-shaped end face can be 2 to 50 times greater than the radius of rounding of its peaks. In addition, the wave height of the wavy end face can smoothly decrease in the radial direction from the hydrodynamic sealing surface.

In addition, the radius of rounding of the vertices of the wave-shaped end face may be greater than the radius of rounding of its depressions by 2 to 50 times, and on the hydrodynamic sealing surface opposite the vertices of the wave-shaped end face, depressions in the form of a triangle are made, one of the vertices of which goes onto the rounding of the wave-shaped end face with the hydrodynamic sealing surface, while the edges of the depression have roundings with the hydrodynamic sealing surface.

In addition, the radius of rounding of the vertices of the wave-shaped end face is 2 to 50 times greater than the radius of rounding of its depressions, and on the hydrodynamic sealing surface opposite each 2 to 5 vertices of the wave-shaped end face, depressions in the form of a triangle are made, one of the vertices of which goes onto the rounding of the wave-shaped end face with the hydrodynamic sealing surface, while the edges of the depression have roundings with the hydrodynamic sealing surface.

In addition, the inner part of the ring can be made of a material with greater hardness than the outer part of the ring.

The shaft seal is also implemented using a sealing ring, which is an elastic polymer ring with flat end surfaces, a cylindrical protrusion is made on the outer cylindrical surface of the ring, a protrusion with a hydrodynamic sealing surface is made on the inner surface of the ring, one of the ends of which is made flat and coincides with the end surface of the ring, and the other end is made wavy with alternating peaks and valleys, and is distinguished by the fact that the wavy end is formed by helical surfaces uniformly distributed around the circumference.

The shaft seal is also implemented using a sealing ring, which is an elastic polymer ring, on one end of which a groove is made in which a meander spring is installed, the inner part of the ring is made of plastic, and the outer part of the ring is made of elastomer, and is distinguished by the fact that on the inner surface of the ring there are uniformly distributed depressions around the circumference. in the form of inclined sectors, extending to the end opposite the groove.

The proposed invention is illustrated by the following drawings:

Fig. 1 - sealing ring, axonometry;

Fig. 2 - sealing ring, longitudinal section;

Fig. 3 - sealing ring, reamer;

Fig. 4 - sealing ring made of materials with different hardness, longitudinal section.

Fig. 5 - sealing ring with a wide profile, axonometry;

Fig. 6 - sealing ring with axially constant profile, development;

Fig. 7 - rings with a profile providing improved lubrication, axonometry;

Fig. 8 - ring with a profile providing increased tightness, axonometry;

Fig. 9 - spring-loaded ring, longitudinal section;

Fig. 10 - spring-loaded ring, axonometry;

Fig. 11 - shaft seal.

The shaft seal is realized by means of a sealing ring (Fig. 1), which is an elastic polymer ring 1 with flat end surfaces 2 and 3. On the outer surface 4 of the ring 1, a cylindrical projection 5 is made. On the inner surface of the ring 1, a projection 6 with a hydrodynamic sealing surface 7 is made. The end face 8 (Fig. 2) of the projection 6 is made flat and coincides with the end surface 3 of the ring 1. The other end face 9 of the projection 6 is made wavy and has a rounding 10 with a hydrodynamic sealing surface 7, as well as peaks 11 and depressions 12.

The height of the wave H (Fig. 3) of the wavy end face 9 is made in the range from 1 to 2 mm. The length of the wave L of the wavy end face 9 is made in the range from 10 to 30 mm, wherein the value nd (d is the diameter of the hydrodynamic sealing surface) of the circumference of the hydrodynamic sealing surface 7 is a multiple of the value of the wavelength L, and the number of waves n is not less than 2. The number of waves is determined by the equation: y = 0.5H • cos(2n • x / d). The inner part 13 (Fig. 4) of the ring 1 can be made of a material with greater hardness than the outer part 14. This makes it possible to increase the wear resistance of the hydrodynamic surface 7 in contact with the sealed shaft.

Fig. 5 shows a ring with a wide profile, in which the radius of rounding R] of the depressions 12 of the wave-like end face 9 is greater than the radius of rounding Ri of its peaks I by 2 - 50 times. Such profile geometry ensures an increase in service life when using lubricants under pressure, and also ensures increased abrasion and wear resistance.

Fig. 6 shows a ring with an axially constant profile, in which the wave height of the wavy end face 9 can smoothly decrease from Hi to H ₂ in the radial direction from the hydrodynamic sealing surface 7. Such a profile provides resistance to abrasive ingress during operation without pressure and at low levels of back pressure. It is also applicable for retaining lubricants under pressure up to 5 MPa.

Fig. 7 shows the design of a ring with a profile that provides improved lubrication. This profile has a radius of rounding R ₂ of the vertices of the wave-like end face that is greater than the radius of rounding r ₂ of its valleys 12 by 2 to 50 times. On the hydrodynamic sealing surface 7 opposite the vertices 11 of the wave-like end face 9, depressions 13 in the form of a triangle are made. The apex 14 of the depression 13 goes onto the rounding 10 of the wave-like end face 9 with the hydrodynamic sealing surface 7. The edges of the depression 13 have roundings 15 with the hydrodynamic sealing surface 7. The hydrodynamic wave geometry of this profile provides improved lubrication, which is especially important when using low-viscosity lubricants, high temperatures, poor heat transfer conditions, or high pressure drops. Compared to standard and wide profile seals, the high lubricity profile provides significantly higher speeds under low pressure drop conditions when using low viscosity lubricants.

It is possible to use rings with a hybrid profile, where waves of increased lubricity alternate with traditional ones, in order to reduce the level of leaks associated with hydrodynamic pumping, while maintaining the advantage in torque compared to standard seals. For example, for every 2 - 5 vertices, a profile with improved lubricity, while the remaining tips have a standard profile. Hybrid seals were developed to provide reduced operating torque and seal heat in oilfield tools, and are also useful in a variety of other applications.

It is also possible to use highly lubricious rings with a beveled profile, which are a hybrid of an axially constant profile with a highly lubricious profile.

Fig. 8 shows a ring with a profile that provides increased tightness. Hydrodynamic surface 7 is formed by helical surfaces 16 with roundings 17. The helical surfaces 16 are uniformly distributed around the circumference. Such a special-purpose seal has a unidirectional hydrodynamic geometry to retain lubricant under pressure and eliminate abrasive wear in units that can withstand or operate at a high hydrodynamic pumping speed. Even water can be used as a lubricant.

Fig. 9, 10 shows a spring-loaded ring, on the end face 18 of which a groove 19 is made, in which a meander spring 20 is installed. The inner part of the ring is made of plastic 21, and the outer part of the ring 22 is made of elastomer. On the inner surface 23 of the ring there are recesses 24 uniformly distributed around the circumference in the form of inclined sectors, emerging on the end face 25 opposite from the groove 19.

These rings are designed for high pressure, unidirectional applications. The ring contains grooves 24 which pump a thin film of lubricant onto the dynamic seal surface during rotation, reducing friction and wear.

The sealing ring is used to seal (hermetically seal) the rotating shaft 26 (Fig. 11). The diameter d of the hydrodynamic sealing surface 7 is approximately equal to the diameter d _B of the shaft 13. The ring 1 is installed in the groove 27 of the fixed housing 28, while the cylindrical protrusion 5 ensures pressing with the required force of the hydrodynamic sealing surface 7 to the shaft 26 due to the fact that the diameter D _K of the groove 27 is smaller than the diameter D of the cylindrical protrusion 5 on the outer cylindrical surface 4. Due to the compressed state of the ring, the shaft is sealed during rotation and the occurrence of the Gough-Joule effect, which appears when the shaft is stretched, is eliminated. condition of the sealing ring and negatively affects its operation. The preferred compression value should be in the range of 5 to 11%. At such values, the necessary pressure of the ring to the shaft is ensured to ensure tightness. A lower value will reduce the provided pressure drop on the sealing ring, and a higher value will lead to high resistance to shaft rotation and heating.

The contact surface of the stationary sealing ring and the rotating shaft becomes dynamic due to the fact that the wave-shaped end face 9 of the projection 6 ensures hydrodynamic wedging of the lubricant film between the hydrodynamic sealing surface 7 and the surface of the rotating shaft 26, thereby eliminating dry friction, which leads to heating and rapid wear of the seal.

The implementation of the wave height H of the wave-shaped end face 9 in the range from 1 to 2 mm, and allows the most effective wedging of the lubricant film between the surfaces rotating relative to each other. A smaller value does not provide a sufficient amount of lubrication. A larger value contributes to the formation of stagnant zones, which also reduces the efficiency of oil film formation.

The implementation of the wavelength L of the wavy end face 9 in the range from 10 to 30 mm allows selecting the optimal number of waves on rings of different diameters. It is obvious that the value of the circumference of the hydrodynamic sealing surface is a multiple of the wavelength, and the number of waves n must be more than two to ensure uniform distribution of the oil film on the shaft. It should be noted that smaller values from the wavelength range are used to seal small-diameter shafts, and larger values are used to seal larger-diameter shafts. Values less or greater than the specified range do not provide sufficient intensity of wedging of the lubricant film.

Preferably, the number of waves of the wavy end face should be determined by the equation y = 0.5N • cos(2n • x / d). With this choice of the number of waves, the best conditions for wedging the lubricant film between the surfaces rotating relative to each other at high speeds are ensured.

Thus, the solutions used in the invention contribute to increasing the efficiency of the shaft seal, which consists in increasing the service life and ensuring tightness throughout the entire service life, and thereby ensure the achievement of the technical result.

Claims

CLAUSE OF THE INVENTION 1. A shaft seal consisting of a sealing ring installed in a groove in a housing and representing an elastic polymer ring with flat end surfaces, a cylindrical protrusion is formed on the outer cylindrical surface of the ring, a protrusion with a hydrodynamic sealing surface in contact with the shaft is formed on the inner surface of the ring, one of the ends of the protrusion is formed flat and coinciding with the end surface of the ring, and the other end is formed wavy with alternating peaks and valleys and having a rounding with a hydrodynamic sealing surface, characterized in that the diameter of the hydrodynamic sealing surface of the protrusion is equal to the diameter of the shaft, wherein the sealing ring is pressed against the shaft due to the fact that the diameter of the groove is less than the diameter of the cylindrical protrusion on the outer cylindrical surface of the sealing ring, wherein the wave height of the wave-shaped end of the sealing ring is formed in the range from 1 to 2 mm, the wavelength of the wave-shaped end is formed in the range from 10 to 30 mm, wherein the value of the circumference of the hydrodynamic the sealing surface is a multiple of the wavelength, and the number of waves is not less than 2. 2. A shaft seal according to item 1, characterized in that the compression of the sealing ring is provided in the range from 5 to 11%. 3. A shaft seal according to item 1 or 2, characterized in that the number of waves is determined by the equation: y = 0.5N • cos(2n • x / d), where H is the wave height; n is the number of waves; d is the diameter of the hydrodynamic sealing surface of the ledge. 4. A shaft seal according to item 1 or 2, characterized in that the radius of rounding of the troughs of the wave-shaped end face is 2 to 50 times greater than the radius of rounding of its peaks. 5. A shaft seal according to item 1 or 2, characterized in that the height of the wave of the wavy end face smoothly decreases in the radial direction from the hydrodynamic sealing surface. 6. A shaft seal according to item 1 or 2, characterized in that the radius of rounding of the peaks of the wave-shaped end face is 2 to 50 times greater than the radius of rounding of its valleys, and on the hydrodynamic sealing surface Opposite the vertices of the wave-shaped end, depressions are made in the shape of a triangle, one of the vertices of which goes onto the rounding of the wave-shaped end with a hydrodynamic sealing surface, while the edges of the depression have roundings with a hydrodynamic sealing surface. 7. A shaft seal according to claim 1 or 2, characterized in that the radius of rounding of the vertices of the wave-shaped end face is greater than the radius of rounding of its depressions by 2 to 50 times, and on the hydrodynamic sealing surface opposite each 2 to 5 vertex of the wave-shaped end face, depressions in the shape of a triangle are made, one of the vertices of which goes onto the rounding of the wave-shaped end face with the hydrodynamic sealing surface, while the edges of the depression have roundings with the hydrodynamic sealing surface. 8. A shaft seal according to item 5, characterized in that on the hydrodynamic sealing surface opposite the vertices of the wave-shaped end face there are depressions in the shape of a triangle, one of the vertices of which extends onto the rounding of the wave-shaped end face with the hydrodynamic sealing surface, while the edges of the depression have roundings with the hydrodynamic sealing surface. 9. A shaft seal according to item 1 or 2, characterized in that the inner part of the ring is made of a material with greater hardness than the outer part of the ring. 10. A shaft seal consisting of a sealing ring installed in a groove in a housing and representing an elastic polymer ring with flat end surfaces, a cylindrical protrusion is made on the outer cylindrical surface of the ring, a protrusion with a hydrodynamic sealing surface in contact with the shaft is made on the inner surface of the ring, one of the ends of the protrusion is made flat and coincides with the end surface of the ring, characterized in that the hydrodynamic sealing surface is formed by helical surfaces with roundings uniformly distributed around the circumference. 11. A shaft seal according to item 10, characterized in that the compression of the sealing ring is provided in the range from 5 to 11%. 12. A shaft seal consisting of a sealing ring installed in a groove in the housing and representing an elastic ring, on one end of which a groove is made in which a seal is installed. meander spring, the inner part of the ring contacts the shaft and is made of plastic, and the outer part of the ring is made of elastomer, characterized in that on the inner surface of the ring there are uniformly distributed depressions in the form of inclined sectors around the circumference, extending to the end opposite the groove. 13. A shaft seal according to item 12, characterized in that the compression of the sealing ring is provided in the range from 5 to 11%. 14. A sealing ring, which is an elastic polymer ring with flat end surfaces, a cylindrical protrusion is made on the outer cylindrical surface of the ring, a protrusion with a hydrodynamic sealing surface is made on the inner surface of the ring, one of the ends of which is made flat and coincides with the end surface of the ring, and the other end is made wavy with alternating peaks and valleys and having a rounding with a hydrodynamic sealing surface, characterized in that the wave height of the wavy end is made in the range from 1 to 2 mm, the wavelength of the wavy end is made in the range from 10 to 30 mm, wherein the value of the circumference of the hydrodynamic sealing surface of the protrusion is a multiple of the wavelength, and the number of waves is at least 2. 15. The ring according to item 14, characterized in that the number of waves is determined by the equation: y = 0.5N • cos(2n • x / d), where H is the wave height; n is the number of waves; d is the diameter of the hydrodynamic sealing surface of the ledge. 16. A ring according to item 14 or 15, characterized in that the radius of rounding of the troughs of the wave-shaped end face is 2 to 50 times greater than the radius of rounding of its peaks. 17. A ring according to item 14 or 15, characterized in that the height of the wave of the wavy end face smoothly decreases in the radial direction from the hydrodynamic sealing surface. 18. A ring according to item 14 or 15, characterized in that the radius of rounding of the vertices of the wave-like end face is greater than the radius of rounding of its depressions by 2 to 50 times, and on the hydrodynamic sealing surface opposite the vertices of the wave-like end face, depressions in the shape of a triangle are made, one of the vertices of which goes onto the rounding of the wave-like end face with hydrodynamic sealing surface, while the edges of the recess are rounded with a hydrodynamic sealing surface. 19. A ring according to item 14 or 15, characterized in that on each 2-5 vertex of the wave-shaped end face, the radius of rounding of the vertices of the wave-shaped end face is greater than the radius of rounding of its depressions by 2-50 times, and on the hydrodynamic sealing surface opposite such vertex, depressions in the form of a triangle are made, one of the vertices of which goes onto the rounding of the wave-shaped end face with the hydrodynamic sealing surface, while the edges of the depression have roundings with the hydrodynamic sealing surface. 20. A ring according to claim 17, characterized in that on the hydrodynamic sealing surface opposite the vertices of the wavy end face there are depressions in the shape of a triangle, one of the vertices of which goes onto the rounding of the wavy end face with the hydrodynamic sealing surface, while the edges of the depression have roundings with the hydrodynamic sealing surface. 21. A ring according to item 5 or 6, characterized in that the inner part of the ring is made of a material with greater hardness than the outer part of the ring. 22. A sealing ring, which is an elastic polymer ring with flat end surfaces, on the outer cylindrical surface of the ring a cylindrical protrusion is made, on the inner surface of the ring a protrusion with a hydrodynamic sealing surface is made, one of the ends of which is made flat and coincides with the end surface of the ring, characterized in that the hydrodynamic sealing surface is formed by helical surfaces with roundings uniformly distributed around the circumference. 23. A sealing ring, which is an elastic polymer ring, on one end of which a groove is made in which a meander spring is installed, the inner part of the ring contacts the shaft and is made of plastic, and the outer part of the ring is made of elastomer, characterized in that on the inner surface of the ring there are recesses uniformly distributed around the circumference in the form of inclined sectors, extending to the end opposite from the groove.