Self-centering seal member for high speed shaft assembly

Abstract

The sealing assembly includes an annular body having a centerline, first and second axial ends spaced apart along the centerline, an inner circumferential surface, and opposing outer circumferential surfaces. The inner surface defines a bore for receiving a shaft, and is sized such that the inner surface of the body frictionally engages with the outer surface of the shaft to connect the component to the shaft. At least three cavities extend axially from the first axial ends of the body and are circumferentially spaced apart about the centerline. Each cavity is located near the bore to define a separate centering body portion between a radially innermost surface portion of the cavity and an axially extending centering surface portion of the inner circumferential surface of the body located inside the cavity. Any radial growth of each centering body portion is less than the simultaneous radial growth of the remainder of the body during rotation of the shaft.

Description

Technical Field

[0001] This invention relates to seals, and more specifically, to sealing components for high-speed shaft assemblies. Background Technology

[0002] Sealing components typically comprise an annular member mounted on a rotatable shaft and providing one or more surfaces, on which a non-rotatable or fixed component is sealed or has one or more flow channels providing such sealing engagement surfaces. Particularly in high-speed applications, such as shaft speeds exceeding 10,000 rpm or even 21,000 rpm, such sealing components experience a substantial radial increase due to the high centrifugal forces generated within the component. If large enough, this radial increase in the sealing component can lead to eccentric operation and excessive shaft vibration due to the resulting imbalance. Summary of the Invention

[0003] On one hand, the present invention is a component for a sealing assembly for sealing around a shaft, the shaft being rotatable about a central axis and having an outer circumferential surface. The sealing component includes an annular body having a centerline, first and second axial ends spaced apart along the centerline, an inner circumferential surface, and opposing outer circumferential surfaces. The inner circumferential surface defines a central bore for receiving the shaft, and its size is configured such that the inner surface of the body frictionally engages with the outer surface of the shaft to connect the component to the shaft. Furthermore, at least three cavities extend axially from the first axial ends, are circumferentially spaced about the centerline, and are located near the bore.

[0004] On the other hand, the present invention is also a component for a sealing assembly for sealing around a shaft rotatable about a central axis and having an outer circumferential surface. The sealing component includes an annular body having a centerline, first and second axial ends spaced apart along the centerline, an inner circumferential surface, and opposing outer circumferential surfaces. The inner circumferential surface defines a central bore for receiving the shaft and is sized such that the inner surface of the body frictionally engages with the outer surface of the shaft to connect the component to the shaft. At least three cavities extend axially from the first axial ends and are circumferentially spaced about the centerline. Each cavity is located near the bore to define a separate centering body portion between a radially innermost surface portion of the cavity and an axially extending centering surface portion of the inner circumferential surface of the body located radially inside the cavity. Thus, any radial growth of each centering body portion is less than the simultaneous radial growth of the rest of the body during rotation of the shaft. Attached Figure Description

[0005] The foregoing summary of the invention and the detailed description of preferred embodiments will be better understood when read in conjunction with the accompanying drawings. To illustrate the invention, illustrative embodiments that are currently preferred are shown in the drawings. However, it should be understood that the invention is not limited to the precise arrangements and means shown. In the figures:

[0006] Figure 1 This is an axial sectional view of a sealing assembly including a sealing component according to the present invention;

[0007] Figure 2 This is a front perspective view of the sealing component;

[0008] Figure 3 This is a rear perspective view of the sealing component;

[0009] Figure 4 This is a front view of the sealing component;

[0010] Figure 5 This is a rear view of the sealing component; and

[0011] Figure 6 yes Figure 1 An enlarged radial cross-sectional view of the sealing assembly shows the radial growth of the sealing component during high-speed rotation. Detailed Implementation

[0012] The use of certain terms in the following description is for convenience only and not as a limitation. The terms “inner,” “inward,” and “outer,” “outward,” respectively refer to directions toward and away from the specified centerline or geometric center of the described element, their specific meanings readily understood from the context of the description. Furthermore, as used herein, the terms “connection” and “linkage” are intended to include, respectively, a direct connection between two components without any other components between them and an indirect connection between components, wherein one or more other components are located between them. Terms include those specifically mentioned above, their derivatives, and words with similar meanings.

[0013] Now refer to the accompanying drawings for details, in which the same numbers are always used to denote the same elements, Figure 1-6 The diagram shows a component 10 for sealing assembly 11 around shaft 1, preferably a dry gas sealing assembly, as described in further detail below. Shaft 1 is oriented about central axis A. CThe shaft 1 rotates and has an outer circumferential surface 2, and is preferably used in relatively high-speed applications, such as engine turbines, compressors, etc. The shaft 1 is configured to rotate at a relatively "high" speed of at least 10,000 revolutions per minute (10,000 rpm) and preferably greater than 21,000 revolutions per minute (21,000 rpm). The sealing component 10 essentially comprises an annular body 12 having a centerline CL, first and second axial ends 12a, 12b spaced apart along the centerline CL, an inner circumferential surface 14, and opposing outer circumferential surfaces 16. The inner circumferential surface 14 defines a central bore 15 for receiving the shaft 1, and its dimensions (i.e., along the diametrical direction) are configured such that the inner surface 14 of the body can frictionally engage with the outer surface 2 of the shaft to connect the component 10 to the shaft 1, preferably by a contraction fit. Furthermore, at least three cavities 18 extend axially from the first axial end 12a, are circumferentially spaced around the centerline CL of the body, and each cavity is located near the bore 15.

[0014] Furthermore, a separate centering body portion 20 is defined between each cavity 18, specifically the radially innermost surface portion 19 of the cavity 18, and an axially extending centering surface portion 21 of the inner circumferential surface 14 of the body located radially inside that particular cavity 18. Preferably, each cavity 18 is formed as an arcuate slot opening, such that each centering body portion 20 is formed as a relatively thin web of material. More specifically, the radial thickness r T ( Figure 1 and 4 The cavity 18 is defined between the innermost radial surface portion 19 and the adjacent centering surface portion 21, and each cavity 18 is positioned relative to the body hole 15 such that the radial thickness r T The value is between approximately 0.050” and approximately 0.300”. Although preferably formed as an arcuate slotted opening, each cavity 18 may alternatively be formed as a substantially circular opening or have any other suitable shape. Furthermore, the annular body 12 preferably has six cavities 18, but may have any other suitable number of cavities 18 as required (e.g., four, five, seven, etc.).

[0015] By providing cavities 18 to the annular body 12, any radial growth of each centering body portion 20 thus formed is substantially less than the simultaneous radial growth of the remaining portion 22 of the body 12 (i.e., the portion without cavities 18) during rotation of the axis 1, such as... Figure 6As shown. That is, during high-speed rotation of shaft 1 at speeds exceeding 10,000 rpm, and preferably exceeding 21,000 rpm, the centrifugal force generated within component 10 causes a fundamental radial strain or increase within the remaining portions 22 of the annular body 12 due to the large mass of these main body portions 22. As a result, when the remaining portions 23 of the inner circumferential surface 14 of the body are radially spaced outward from the outer surface 2 of the shaft, especially when shaft 1 rotates at an angular velocity / rotational speed greater than 10,000 rpm and more significantly exceeding 21,000 rpm, each centering surface portion 21 remains in contact with (or at least adjacent to) the outer surface 2 of the shaft. Furthermore, each centering surface portion 21 is positioned such that the annular body 12 is positioned around the axis A of the shaft. C Centering. In other words, at least three surface portions 21 (or six portions 21, etc.) are spaced apart at substantially equal angles around the circumference of the axis 1, such that the contact between the surface portions 21 and the outer surface 2 of the axis positions the centerline CL of the body 12 relative to the axis A. C Basically coaxial.

[0016] By keeping the sealing component 10 around axis A during the high-speed rotation of shaft 1. C Centering minimizes (or even eliminates) dynamic radial imbalance and avoids eccentric operation, thereby essentially eliminating the main source of vibration for shaft 1. Since the basic components and features have been described above, these and other aspects of this sealing component 10 will be described in more detail below.

[0017] Reference Figure 1-3 In a currently preferred application, the annular body 12 of the sealing member 10 has a radially outwardly extending shoulder 30 adjacent to the first axial end of the body 12a and having an axial length L. S ( Figure 1 Thus, the mass of the annular body 12 at the first axial end 12a is substantially greater than the mass of the annular body 12 at the second axial end 12b. Therefore, the centrifugal growth of the sealing member 10 is greatest in the region of the shoulder 30. Therefore, the cavity 18 is preferably positioned to extend axially inward from the first end 12a of the body, thereby being disposed radially inside the shoulder 30. Preferably, the axial length L of each cavity 18 is... C At least 30 axial length L of the shoulder S One-quarter, such as Figure 1 As shown. Most preferably, the axial length L of each cavity 18 is... C It is at least 0.250 inches (0.250") in length, regardless of whether the body 12 has a shoulder 30.

[0018] Furthermore, the outer circumferential surface 16 of the annular body 12 is preferably formed by a plurality of axially spaced adjacent surface portions 17, each having an outer diameter (not shown) greater than or less than the outer diameter of another surface portion 17. This variation in outer diameter allows for the mounting of different sealing elements or components around the sealing member 10. Preferably, the annular body 12 of the sealing member 10 includes a sealing flow channel surface (not shown), a mounting surface 32 for sealing the flow channel 3, an axially extending annular mounting groove 34 for the axial face sealing member 4, and one or more of a plurality of radially outwardly extending ridges 36 for providing a portion of a labyrinth seal. However, the sealing member 10 may be formed without any of these features or with any other suitable sealing features or structures.

[0019] Special reference Figure 1 In one exemplary application, the sealing element 10 is incorporated into a dry gas sealing assembly 11, which includes a generally tubular sealing channel 3 and a generally tubular face seal retainer 5 disposed around a separated portion 17 of an outer surface 16 and an axial face seal member 4 mounted in an annular groove 34. The sealing assembly 11 also includes: a housing assembly 6 disposed around the sealing element 10; three additional axial face seal members 4 coupled to the housing assembly 6 or the face seal retainer 5, each including a rotatable and fixed sealing member 4; a circumferential sealing member 7 disposed around the sealing channel 3; and a biasing assembly 8 for biasing the face seal members 4. However, the sealing element 10 can be used in any suitable sealing assembly, such as including only one or more circumferential seals, only axial face seals (formed as oil seals), etc. Furthermore, the annular body 12 may have any other suitable structure, such as being formed without shoulders and having a substantially constant outer surface 16, having cavities 18 formed at the two ends 12a, 12b of the body 12, or having cavities 18 extending inward only from the second axial end 12b of the body, etc.

[0020] Those skilled in the art will understand that changes can be made to the above embodiments without departing from the broad inventive concept of the invention. Therefore, it should be understood that the invention is not limited to the specific embodiments disclosed, but is intended to cover modifications within the spirit and scope of the invention as generally defined in the appended claims.

Claims

1. A component for sealing an assembly around a shaft, the shaft being rotatable about a central axis and having an outer peripheral surface, the component comprising: An annular body having: a centerline; a first axial end and a second axial end spaced apart along the centerline; and an inner circumferential surface; The inner circumferential surface defines a central hole for receiving the shaft and is sized such that the inner surface of the body frictionally engages with the outer surface of the shaft to connect the component to the shaft; and at least three cavities extending axially from the first axial end, circumferentially spaced about the centerline, and located near the hole. Each individual centering body portion is defined between each cavity and an axially extending centering surface portion on the inner circumferential surface of the body located radially inside the cavity. Any radial growth of each centering body portion is less than the simultaneous radial growth of the remainder of the body during rotation of the shaft, such that each centering surface portion remains in contact with the outer circumferential surface of the shaft when the remainder of the inner circumferential surface of the annular body is radially spaced outward from the outer circumferential surface of the shaft. Each centering surface portion is positioned to center the annular body about the central axis of the shaft. The annular body has a shoulder that extends radially outward adjacent to the first axial end; The radially outwardly extending shoulder is provided with a plurality of radially outwardly extending ridges for a portion of the labyrinth seal.

2. The component as claimed in claim 1, wherein, Each centering body portion has a radial thickness defined between the innermost radial surface portion of each cavity and the adjacent centering surface portion, the value of which is between 0.50 and 0.300 inches.

3. The component as claimed in claim 1, wherein, When the shaft rotates at a speed greater than 10,000 revolutions per minute, each centering surface portion remains in contact with the outer surface of the shaft.

4. The component as claimed in claim 1, wherein, The shoulder portion causes the mass of the annular body at the first axial end to be greater than the mass of the annular body at the second axial end.

5. The component as claimed in claim 4, wherein, The shoulder has an axial length, and the axial length of each cavity is at least half the axial length of the shoulder.

6. The component as claimed in claim 1, wherein, The axial length of each cavity is at least 250 / 1000 inches.

7. The component as claimed in claim 1, wherein, Each cavity is formed as an arc-shaped slotted opening.

8. The component as claimed in claim 1, wherein, The annular body has at least six cavities.

9. The component as claimed in claim 1, wherein, The annular body includes at least one of a sealing flow channel surface, a mounting surface for sealing the flow channel, and an axially extending annular mounting groove for the axial face seal.

10. The component as claimed in claim 1, wherein, The outer peripheral surface of the annular body includes at least a first outer surface portion and a second outer surface portion, each having an outer diameter, wherein the outer diameter of the first outer surface portion is greater than the outer diameter of the second outer surface portion.

11. A component for sealing an assembly around a shaft, the shaft being rotatable about a central axis and having an outer circumferential surface, the component comprising: An annular body having: a centerline; a first axial end and a second axial end spaced apart along the centerline; and an inner circumferential surface; The inner circumferential surface defines a central bore for receiving the shaft and is sized such that the inner surface of the body frictionally engages with the outer surface of the shaft to connect the component to the shaft; and at least three cavities extending axially from a first axial end and circumferentially spaced about the centerline, each cavity being located near the bore to define a separate centering body portion between a radially innermost surface portion of the cavity and an axially extending centering surface portion of the inner circumferential surface of the body located radially inside the cavity, any radial growth of each centering body portion being less than the simultaneous radial growth of the remainder of the body during rotation of the shaft, such that each centering surface portion remains in contact with the outer circumferential surface of the shaft when the remainder of the inner circumferential surface of the annular body is radially spaced outward from the outer circumferential surface of the shaft, each centering surface portion being positioned to center the annular body about the central axis of the shaft; The annular body has a shoulder that extends radially outward adjacent to the first axial end; The radially outwardly extending shoulder is provided with a plurality of radially outwardly extending ridges for a portion of the labyrinth seal. Each cavity is formed as an arc-shaped slotted opening, and the annular body has at least six cavities.

12. The component as claimed in claim 11, wherein, Each centering body portion has a radial thickness defined between the innermost radial surface portion of each cavity and the adjacent centering surface portion, the value of which is between 0.50 and 0.300 inches.

13. The component as claimed in claim 11, wherein, When the shaft rotates at a speed greater than 10,000 revolutions per minute, each centering surface portion remains in contact with the outer surface of the shaft.

14. The component as claimed in claim 11, wherein, The shoulder portion is such that the mass of the annular body at the first axial end is greater than the mass of the annular body at the second axial end, the shoulder portion has an axial length, and the axial length of each cavity is at least half the axial length of the shoulder portion.

15. The component as claimed in claim 11, wherein, The annular body includes at least one of a sealing flow channel surface, a mounting surface for sealing the flow channel, and an axially extending annular mounting groove for the axial face seal.

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