Seal assembly including connecting channel

Abstract

A seal assembly for sealing a shaft bearing includes a seal housing, first and second seal rings retained by the seal housing, an annular chamber formed between the first and second seal rings and a connecting channel configured to place the annular chamber in fluid communication with a bearing-housing-side oil space. When the seal assembly is installed on a shaft, the connecting channel is configured to permit a fill-level equalization between the oil space and the annular chamber when the oil space is filled to a first possible fill level (N.sub.1) and to prevent the fill-level equalization between oil space and annular chamber when the oil space is filled to a second possible fill level (N.sub.2).

Claims

1. A seal assembly for sealing a shaft bearing, the seal assembly comprising: a seal housing; a first seal ring and a second seal ring retained by the seal housing, the first seal ring and the second seal ring each being configured to encircle a shaft and the first seal ring having a sliding diameter D, an annular chamber formed between the first seal ring and the second seal ring; and a connecting channel configured to place the annular chamber in fluid communication with a bearing-housing-side oil space, wherein, when the seal assembly is installed on a shaft, the connecting channel is configured to permit a fill-level equalization between the oil space and the annular chamber when the oil space is filled to a first possible fill level (N.sub.1), and to prevent the fill-level equalization between oil space and annular chamber when the oil space is filled to a second possible fill level (N.sub.2).

2. The seal assembly according to claim 1, wherein, when the seal assembly is installed on the shaft, the first possible fill level (N.sub.1) lies above a bottom of the annual chamber by at most 100% of the sliding diameter D.

3. The seal assembly according to claim 2, wherein, when the seal assembly is installed on the shaft, a distance (d.sub.2) of the second possible fill level (N.sub.2) from the bottom of the annular chamber is at most 95%, of a distance (d.sub.1) of the first possible fill level (N.sub.1) from the bottom of the annular chamber and at least 20% of a distance (d.sub.1) of the first possible fill level (N.sub.1) from the bottom of the annular chamber.

4. The seal assembly according to claim 2, wherein, when the seal assembly is installed on the shaft, a distance (d.sub.2) of the second possible fill level (N.sub.2) from the bottom of the annular chamber is at most 80%, of a distance (d.sub.1) of the first possible fill level (N.sub.1) from the bottom of the annular chamber and at least 70% of a distance (d.sub.1) of the first possible fill level (N.sub.1) from the bottom of the annular chamber.

5. The seal assembly according to claim 1, wherein, when the seal assembly is installed on the shaft, the first possible fill level (N.sub.1) lies above a bottom of the annual chamber by at most 40% of the sliding diameter D.

6. The seal assembly according to claim 5, wherein, when the seal assembly is installed on the shaft, a distance (d.sub.2) of the second possible fill level (N.sub.2) from the bottom of the annular chamber is at most 95%, of a distance (d.sub.1) of the first possible fill level (N.sub.1) from the bottom of the annular chamber and at least 20% of a distance (d.sub.1) of the first possible fill level (N.sub.1) from the bottom of the annular chamber.

7. The seal assembly according to claim 5, wherein, when the seal assembly is installed on the shaft, a distance (d.sub.2) of the second possible fill level (N.sub.2) from the bottom of the annular chamber is at most 80%, of a distance (d.sub.1) of the first possible fill level (N.sub.1) from the bottom of the annular chamber and at least 70% of a distance (d.sub.1) of the first possible fill level (N.sub.1) from the bottom of the annular chamber.

8. The seal assembly according to claim 1, wherein, when the seal assembly is installed on the shaft, an opening of the connecting channel into the annular chamber or an oil-chamber-side inlet of the connecting channel in a deepest or a central point has a distance (a) from the first possible fill level (N.sub.1) that satisfies the relation D/20a2D/3.

9. The seal assembly according to claim 1, wherein, when the seal assembly is installed on the shaft, an opening of the connecting channel into the annular chamber or an oil-chamber-side inlet of the connecting channel in a deepest or a central point has a distance (a) from the first possible fill level (N.sub.1) that satisfies the relation D/11aD/9.

10. The seal assembly according to claim 1, wherein, when the seal assembly is installed on the shaft, an opening of the connecting channel into the annular chamber or an oil-chamber-side inlet of the connecting channel in a deepest or a central point has a distance (b) from the second possible fill level (N.sub.2) that satisfies the relationship D/20b2D/3.

11. The seal assembly according to claim 1, wherein, when the seal assembly is installed on the shaft, an opening of the connecting channel into the annular chamber or an oil-chamber-side inlet of the connecting channel in a deepest or a central point has a distance (b) from the second possible fill level (N.sub.2) that satisfies the relationship D/11bD/9.

12. The seal assembly according to claim 1, wherein the connecting channel includes a section that partially encircles the shaft.

13. The seal assembly according to claim 1, wherein a section of the connecting channel extends between two housing rings of the seal housing.

14. The seal assembly according to claim 1, wherein the seal housing includes a venting channel extending above the first possible fill level (N.sub.1) of the oil space and connecting the annular chamber to the oil space.

15. The seal assembly according to claim 14, wherein the venting channel includes at least one bend.

16. The seal assembly according to claim 14, wherein, the venting channel includes a descending section that drops off into the oil space.

17. The seal assembly according to claim 16, wherein the descending section has a length (L) that is at least three times a diameter (d) of an opening of the venting channel into the oil space.

18. The seal assembly according to claim 1, wherein the connecting channel includes a section that partially encircles the shaft, wherein a section of the connecting channel extends between two housing rings of the seal housing, wherein the seal housing includes a venting channel extending above the first possible fill level (N.sub.1) of the oil space and connecting the annular chamber to the oil space, wherein the venting channel includes at least one bend, and wherein the venting channel includes a descending section that drops off into the oil space.

19. A seal assembly for sealing a shaft bearing, the seal assembly comprising: a seal housing; a first seal ring and a second seal ring retained by the seal housing, the first seal ring and the second seal ring each being configured to encircle a shaft and the first seal ring having a sliding diameter D, an annular chamber formed between the first seal ring and the second seal ring; and a connecting channel having a first opening in the annular chamber and a second opening in a bearing-housing-side oil space, wherein when the seal assembly is installed on a shaft, the bearing-housing-side oil space has a maximum operating fill level and a minimum operating fill level, and wherein the second opening is located at a distance from a bottom of the bearing-housing-side oil space greater than the minimum operating fill level and less than the maximum operating fill level.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIGS. 1a-1d show cross-sections of an exemplary seal assembly according to the present disclosure in various sections; and

(2) FIG. 2 shows a schematic overview depiction of the seal assembly of FIGS. 1a-1d.

DETAILED DESCRIPTION

(3) In FIGS. 1a-1d various sections of an exemplary embodiment of the disclosed seal assembly 100 are each shown in section. The seal assembly 100 serves to seal the (not-shown) bearing of a shaft 10, which is disposed in a (partly shown) bearing housing 12. FIGS. 1a, 1c, and 1d show a cross-section along the intended axis of rotation R of the shaft 10 which is horizontal in the installed position (wherein the respective sectional planes have different inclinations with respect to the horizontal); in FIG. 1b a cross-section is shown perpendicular to this axis R.

(4) The seal assembly 100 comprises a seal housing 110 as well as, in the present case, two identically formed seal rings 121 and 122 retained by the seal housing, which seal rings 121 and 122 each abut on a shaft-protecting sleeve 11 of the shaft 10 and thus both have the same sliding diameter D. An annular chamber 130 is formed between the seal rings 121 and 122 that is delimited by the shaft-protecting sleeve 11, the seal housing 110, and the seal rings 121, 122.

(5) In the seal housing 110 a connecting channel 111 is formed that includes a section 111a starting from a bearing-housing-side oil space 13 that extends horizontally in the present case. At point 111 the connecting channel 111 has a bend and here leaves the sectional plane visible in FIG. 1a; its further course is shown in FIG. 1b, wherein it can be seen that the connecting channel 111 partially encircles the shaft 10 in a section 111b extending in the rotational direction (namely around the center angle , which in the present case is between 75 and 90). For example, the connecting channel can be introduced (wholly or partially) in this section 111b in at least one surface of at least one housing ring, in particular turned-in or milled-in, from which the housing 110 among other things can be assembled. In the case shown, the connecting channel 111 is sealed toward the shaft by seal ring beads 121a, 122b; O-rings 113 and 114 serve as outward seals.

(6) In FIG. 1b a first possible fill level N.sub.1 and a second possible fill level N.sub.2 are marked for the oil space 13 (visible in FIG. 1a) surrounding a section of the shaft 10; here all fill levels that are conceivable or settable between the empty and the full oil space are to be understood as possible fill levels that define an abstract horizontal cross-sectional plane. Preferably N.sub.1 corresponds to a fill level specified by the bearing manufacturer; it is usually located in the region of the intended axis of rotation R of the shaft.

(7) Embodiments are advantageous wherein the first possible fill level N.sub.1 lies at most 100%, 80%, 60%, 50% or even at most 40% of the slide diameter D of one of the seal rings above the bottom of the annular chamber (in the installed position). In the example shown in FIG. 1b the marked first possible fill level lies at the height of the axis of rotation R and the second possible fill level N.sub.2 therebelow.

(8) The distance a+b from N.sub.1 to N.sub.2 is preferably in the range from 10% to 77% of the sliding diameter D of at least one of the seal rings, in particular between 15% and 25% of the sliding diameter.

(9) In a further bend 111 the connecting channel merges into a section 111c, which is depicted in FIG. 1c and which leads into the annular chamber 130.

(10) In the installed position the connecting channel 111 of the embodiment shown in FIGS. 1a-1c is thus disposed continuously below the first possible fill level N.sub.1; in particular its channel bottom, on which oil can flow, extends below this fill level N.sub.1. When the oil space has a fill level at the level of this fill level N.sub.1, the connecting channel 111 is thus flooded continuously, i.e., it sets the same oil level in the oil space 13 and the annular chamber 130. Both seal rings 121 and 122 are thus lubricated and thus protected from excessive wear and heat development. Here the seal ring 122 represents the main seal ring, which in the usual case (namely as long as it is intact) ensures the sealing of the shaft bearing; the seal ring 121 is the auxiliary seal ring for the case of a defect of the main seal ring 122.

(11) In the region around a second bend 111, in particular in section 111c, which in the present case represents the vertically highest section of the connecting channel in the installed position, the channel bottom extends above the second possible fill level N.sub.2. The opening 111d into the annular chamber has a distance a (in a central point or a lowest point in the installed position) from the first possible fill level N.sub.1, wherein, for example, it applies that D/20a2D/3, in the present case even D/9aD/11. For the second possible fill level N.sub.2 the opening 111d has a distance b (in a central point or a lowest point in the installed position), which, analogous to the inequality D/20b2D/3, in the present case satisfies D/9bD/11.

(12) Due to the position of the opening 111d above the second possible fill level N.sub.2, even with a connecting channel 111 sealed in an air-tight manner a flow from the oil space 13 into the annular chamber 130 can be prevented by a lowering of the fill level in the oil space 13 to this first fill level N.sub.2; the connecting channel 111 then prevents a fill-level equalization between oil space and annular chamber. In the case of a defect of the main seal ring 122, wherein oil flows outward from the annular chamber 130, in this way an afterflow of oil from the oil space can be prevented and the annular chamber 130 is thus drained. In this case the auxiliary seal ring 121 then effects the reliable sealing of the shaft bearing.

(13) In FIG. 1d a cross-section of the seal assembly 100 is depicted in a further section, which in the installed position lies above the first possible fill level N.sub.1: In the exemplary embodiment shown a venting channel 112 is formed in this region, which venting channel 112 connects the annular chamber 130 to the oil space 13.

(14) In the example shown, the venting channel 112 comprises a first section 112a as well as a second section 112b and a third section 112c, which are separated from one another by bends 112 or 112 such that (in particular in the temporary case when the annular chamber 130 is drained) the penetration of spray oil through the venting channel 112 into the annular chamber is reduced. In addition, in the present case the third section 112c is formed narrower than the sections 112a, 112b, which further reduces the probability of spray oil penetration.

(15) Furthermore, in the installed position shown, the section 112c drops off over a length L toward the oil space 13 so that in this region if appropriate any sprayed-in oil can flow back into the oil space. At its opening into the oil space the venting channel has a diameter d. An embodiment is particularly advantageous for which dL/3 holds: The possibility of spray oil penetrating though the venting channel into the annular chamber is thereby further minimized.

(16) In FIG. 2 a simplified view is shown of the seal assembly 100 for sealing a shaft bearing 14 of the shaft 10 in the installed position. To be noted in particular is the connecting channel 111, extending continuously below the first possible fill level N.sub.1 of the oil space, including the sections 111a, 111b, 111c, of which the section 111b partially encircles the shaft 10 and of which the section 111c (including its associated channel bottom and the opening 111d into the annular chamber 130) lies above the second possible fill level N.sub.2 of the oil space 13.

(17) In the upper region a venting channel 112 is disposed whose section 112c opening into the oil space drops off toward the oil space 13. The oil space 13 in turn includes a venting line 15 outside the bearing housing 12.

(18) A seal assembly 100 for sealing a shaft bearing 14 is disclosed, which comprises a seal housing 110 as well as two seal rings 121, 122 retained by the seal housing. The seal rings 121, 122 are each configured to encircle a shaft 10 so that an annular chamber 130 is formed between them. The annular chamber 130 is connected to the oil space 13 by a connecting channel 111. In the installed position of the seal assembly, with a first possible fill level N.sub.1 of the oil space the connecting channel realizes a fill-height compensation between oil space and annular chamber; with a second possible fill level N.sub.2 of the oil space the connecting channel prevents the fill-height compensation.

(19) Furthermore, a seal housing 110 for such a seal assembly is disclosed.

(20) Representative, non-limiting examples of the present invention were described above in detail with reference to the attached drawings. This detailed description is merely intended to teach a person of skill in the art further details for practicing preferred aspects of the present teachings and is not intended to limit the scope of the invention. Furthermore, each of the additional features and teachings disclosed above may be utilized separately or in conjunction with other features and teachings to provide improved seal assemblies.

(21) Moreover, combinations of features and steps disclosed in the above detailed description may not be necessary to practice the invention in the broadest sense, and are instead taught merely to particularly describe representative examples of the invention. Furthermore, various features of the above-described representative examples, as well as the various independent and dependent claims below, may be combined in ways that are not specifically and explicitly enumerated in order to provide additional useful embodiments of the present teachings.

(22) All features disclosed in the description and/or the claims are intended to be disclosed separately and independently from each other for the purpose of original written disclosure, as well as for the purpose of restricting the claimed subject matter, independent of the compositions of the features in the embodiments and/or the claims. In addition, all value ranges or indications of groups of entities are intended to disclose every possible intermediate value or intermediate entity for the purpose of original written disclosure, as well as for the purpose of restricting the claimed subject matter.

REFERENCE NUMBER LIST

(23) 10 Shaft 11 Shaft-protecting sleeve 12 Bearing housing 13 Oil space 14 Shaft bearing 15 Venting line of the oil space 100 Seal assembly 110 Seal housing 111 Connecting channel 111a, 111b, 111c Sections of the connecting channel 111 111d Opening of the connecting channel into the annular chamber 130 111, 111 Bends of the connecting channel 112 Venting channel of the annular chamber 130 112a, 112b, 112c Sections of the venting channel 112 112, 112 Bends of the venting channel 112 113, 114 O-ring 121 Seal ring (auxiliary seal ring) 122 Seal ring (main seal ring) 122a Seal ring bead of the seal ring 122 130 Annular chamber d Diameter of the venting channel at its opening into the oil space 13 d.sub.1 Distance of the first possible fill level from the bottom of the annular chamber d.sub.2 Distance of the second possible fill level from the bottom of the annular chamber D Sliding diameter of the seal rings G Bottom of the annular chamber in the installed position L Length of section 112c of the venting channel N.sub.1 First possible fill level N.sub.2 Second possible fill level R Axis of rotation of the shaft 1