Patent Application
20140165396
The present disclosure relates generally to a self-centering seal. More particularly, the present disclosure relates to a self-centering seal for a counterbore.
Many components of an internal combustion engine are subject to high loads and wear during operation of the engine. One such component, for example, is the engine block, which may experience loads from combustion events occurring within combustion chambers formed by the cylinder head, pistons, and cylinder bores of the engine block. These events may subject the engine block to high loads and stresses, including thermal stresses and mechanical stresses, which may be transmitted to the engine block at, among other locations, the cylinder head, which is mounted to a top deck of the engine block, and the cylinder bores. As a result of these stresses, small cracks may form, or general wear may occur, within the engine block, particularly within or near the cylinder bores at the top deck of the engine block. In addition, wear and erosion may occur along edges of fluid passages surrounding the cylinder bores and opening through the top deck.
U.S. Pat. No. 5,222,295 teaches a method for repairing diesel engine cylinder blocks. Specifically, the cited reference teaches a method for removing selected portions along the longitudinal axis of a cylinder bore of the engine block, and installing inserts within the cavities formed within the cylinder bore. Although the described method may adequately repair cracks occurring within the cylinder bore, the reference does not contemplate cracks that may radiate from the cylinder bore and across the top deck of the engine block, or that may occur along edges of the surrounding water passages. Nor does the method address providing sealing for a relatively shallow insert or how sealing, if it were to be provided, would be centered around the cylinder bore or water passages. Additionally, there remains a continuing need for methods of engine block repair and remanufacture that are effective and economically feasible.
In one aspect, a self-centering seal for a counterbore with an inner passageway and a counterbore diameter defining a recessed area is described. The self-centering seal includes an annular shape including an aperture defined by an inner diameter matched to the diameter of the inner passageway, a circular outer edge having an outer diameter less than the counterbore diameter, a sealing surface at least partially disposed between the inner diameter and the circular outer edge, and a plurality of centering tabs projecting form the outer edge.
In another aspect, a method is described for manufacturing an engine block includes removing material from the top deck of the engine block surrounding a first opening, such as a fluid passage, cylinder bore, or attachment bore, to create a first recessed area including a first bottom surface and a diameter defining a sidewall. The method also includes centering a first seal around the first opening on the first bottom surface, the first seal including an aperture defined by an inner diameter that matches the first opening, a circular outer edge having an outer diameter less that the first recessed area diameter, a sealing surface at least partially disposed between the inner diameter and the outer edge, and a plurality of centering tabs projecting from the outer edge. The centering tabs are arranged to contact the first recessed area sidewall to align the first seal inner diameter about the first opening. The method additionally includes positioning a first insert within the first recessed area and against the first seal.
An exemplary embodiment of a self-centering seal is 110 is shown generally in
In one embodiment, a sealing surface 124 is at least partially disposed between the inner diameter 112 and the outer diameter 118. The sealing surface 124 may be provided on either the top face 122 or the bottom face 124 of the seal 110. For example, the sealing surface 124 may be provided on the top surface 120 and extend around the extent of the outer edge 116 but not extend inwardly to the inner diameter 112. In another embodiment, the sealing surface 124 may be provided on the entire top face 122 but not on the bottom face 124. In a further embodiment, the seal may be provided on both the top surface 120 and the bottom surface 122.
The self-centering seal 110 is provided with a plurality of centering tabs 130 projecting from the outer edge 116. In an exemplary embodiment, the seal 110 may be provided with from 2-10 centering tabs 130 although it may be contemplated for the seal 110 to be provided with more than 10 centering tabs 130. Seal 110 as depicted in
The centering tabs 130 are sized to project a length L1 from the outer edge 116 of the seal 110. The length L1 may be about 0.25 mm to about 3 from the circular shape of the outer edge 116. In a preferred embodiment, the length L1 is about 1 mm. The centering tabs 130 each extend an angular distance dO around a portion of the outer edge 116. The angular distance dO is measured from a first point 132 from which the tab extends away from the generally circular outer edge 116 to a second point 134 at which the tab 130 terminates and the outer edge 116 resumes its generally circular shape. Each tab 130 extends an angular distance dO at the outer edge 116 of about 0.25° to about 3.0°. In a preferred embodiment, the angular distance dO is about 1.0°.
As described above, the self-centering seal 110 is provided with a sealing surface 124. The sealing surface 124 may be configured and provided in the form of an o-ring, a rubber coated metal gasket or an edge bonded integral seal.
The self-centering seal 110 may be used in a counterbore 150 as depicted in
As described above self-centering seal 110 is provided with an aperture 114 defined by an inner diameter 112. The aperture 114 of the self-centering seal is sized to match the inner passageway diameter DA. The outer edge 116 of the seal 110 having diameter 118 is provided such that it is less than that of the counterbore diameter DB. However, the centering tabs 130 project length L1 to span the distance D2 between the outer edge 116 and sidewall 154 and center the aperture 114 of the seal 110 around the passageway 152. By providing the centering tabs 130 around the outer edge 116 of the seal 110, the seal 110 is seated in the counterbore 150 on bottom surface 158 without the need of tools to assure proper centering of the seal 110.
An exemplary embodiment of an engine block 10, also referred to as a cylinder block, in which the self-centering seal may be used is shown generally in
The engine block 10 may be a one-piece casting and may generally include an upper section 12 and a lower section 14. The upper section 12 of the engine block 10 may include a variety of openings, such as cylinder bores, fluid passages, and attachment bores. In the depicted embodiment, the upper section 12 may include a plurality of cylinder bores 16 formed within the engine block 10 and opening through a top deck 18 of the engine block 10. Although six cylinder bores 16 are shown, it should be appreciated that the engine block 10 may include any number of cylinder bores 16, each of which may or may not include a cylinder liner. A cylinder head (not shown) may be attached to the engine block 10, such as, for example, by using a plurality of attachment bolts that may be threadably received within a corresponding number of attachment bores 20. The cylinder head, as is known in the art, may seal each of the cylinder bores 16, thus creating combustion chambers therein, and may provide a structure for supporting intake and exhaust valves and/or ports, fuel injectors, necessary linkages, and/or other known devices or structures.
The upper section 12 of the engine block 10 may also include a plurality of fluid passages 22, such as water passages, circumferentially spaced about each cylinder bore 16. Although eight fluid passages 22 are shown, it should be appreciated that any number of fluid passages 22 may be provided throughout the engine block 10. Each fluid passage 22 may be formed within the engine block 10 and may open through the top deck 18, as shown. It should be appreciated that the fluid passages 22, and additional fluid passages and/or chambers within the engine block 10, may form a water jacket or other similar cooling system for controlling circulation of a coolant and providing proper cooling of the engine block 10. It should also be appreciated that the fluid passages 22, which may include ferrule type coolant directors, and/or the water jacket may be configured to provide cooling of the cylinder head, or components thereof, attached to the engine block 10. Furthermore, while the diameters of the fluid passages 22 shown in
The lower section 14 of the engine block 10 may also include and/or define a portion of the water jacket described above. The lower section 14 may be of conventional form, and may include a crankcase, in which a crankshaft rotates. The lower section 14 of the engine block 10, as well as the cylinder head and the internal combustion engine, in general, are not within the scope of the present disclosure and, therefore, will not be described herein in greater detail. It should be appreciated, however, that the engine block 10, including features described herein, is contemplated for use with any type and/or configuration of internal combustion engine.
Turning now to
During a manufacturing process 40 (
As used herein, “manufacturing” may refer broadly to the original manufacture, remanufacture, repair, or other similar process associated with the engine block 10. Specifically, engine block material, which may include one or more of the cracks 30, 34, 36, and 38 shown in
As shown in
In one embodiment, the first recessed area 46 has a diameter D1 of about 20 mm to about 24 mm and a depth X1 of about 10 mm to about 14 mm. In another embodiment, the first recessed area 46 has a diameter D1 of about 22 mm and a depth X1 of about 12 mm. In yet another embodiment, the first recessed area 46 has a diameter D1 of about 30 mm to about 34 mm and a depth X1 of about 10 mm to about 14 mm. In yet a further embodiment, the first recessed area 46 has a diameter D1 of about 32 mm and a depth X1 of about 12 mm. In another embodiment, the engine block 10 has a plurality of first recessed areas 46 with some of the first recessed areas having diameter D1 of about 20 mm to about 24 mm while other of the first recessed areas having a diameter D1 of about 30 mm to about 34 mm. For example, the engine block 10 of
Turning now to
When placed in the first recessed area 46, the first seal 90 is positioned such that the inner opening 92 of the first seal 90 is aligned with the opening of the fluid passage 22. For example, first seal 90 may be a self-centering seal 110 with an outer edge 116 having an outer diameter 118 (e.g., D7) that is less than diameter D1 and a plurality of centering tabs 130 provided around the outer edge 116 such that the first seal 90 self-centers around passage 22 in the manner described above with regard to the self-centering seal 110. The surface 94 of the first seal 90 is placed against the first bottom surface 48 of the first recessed area 46.
Turning now to
The first insert 50 has a thickness T1 and an outer diameter D2. The combined thickness T1 of the first insert 50 and thickness T3 of the first seal 90 is configured to be equal to or greater than the depth X1 of the first recessed area 46. For example, in one embodiment, the first insert 50 has a thickness T1 of about 12 mm to 12.7 mm. In another embodiment, the first insert 50 has a thickness T1 of about 12.35 mm. In a further embodiment, the first insert 50 has a thickness T1 of about 3 mm to about 7 mm, preferably about 5 mm. The diameter D2 of the first insert 50 is configured to allow the first insert 50 to fit securely within the first recessed area 46. Thus, the diameter of the first insert 50 is matched to the corresponding first recessed area. For example, where an interference fit is used to secure the first insert 50 in the first recessed area 46, the diameter D2 of the first insert 50 is configured to be slightly larger than the diameter D1 of the first recessed area 46. In one embodiment, the first insert 50 has a diameter D2 about 0.02 mm to about 0.05 mm greater than the diameter D1 of the first recessed area 46, and preferably about 0.035 mm greater. As indicated above, a plurality of first recessed areas 46 may be made in the engine block 10 and some of the plurality of first recessed areas may be sized different than some of the other first recessed areas. Likewise, first inserts 50 and first seals 90 with different diameters may be used on the same engine block 10 to match up with corresponding first recessed areas. In one embodiment, an engine block 10 includes a plurality of first inserts 50, some of which have a diameter that is about 40% or more greater than the diameter of the remaining plurality of first inserts.
In yet another embodiment, the first insert 50 may have a sealing material such as rubber, bonded to its bottom surface 60 using techniques knowing in the art for bonding materials such as rubber to metal, effectively forming a combined first insert 50 and first seal 90. The combined first seal 90 and first insert 50 could then be placed into the first recessed area 46 in a single step.
As shown in
The first recessed area 46 has a depth X1 that is greater than the depth X2 of the second recessed area 70 and the second depth X2 does not extend down to a depth such that the formation of the second recessed area 70 disturbs the first seal 90. In some embodiments, for example, the depth of the first recessed area may be 50% or more greater that the depth of the second recessed area. As a result, a lens-shaped shoulder 72 is formed on the first insert 50. In some embodiments, however, it may be possible to form the first insert 50 with the shoulder 72 as opposed to machining the shoulder when forming the second recessed area 70. When the first insert 50 is installed, the shoulder may be positioned toward the bore. Thus, the second recessed area 70 may be formed without removing material from the first insert 50.
It will be understood that engine block material may be removed from the top deck 18 surrounding each of the plurality of cylinder bores 16, resulting in a corresponding number of second recessed areas 70. Furthermore, it will be understood that the diameter D4 and depth X2 of the second recessed area 70 may vary for different engine sizes and types and may vary on a single engine block if desired. In one embodiment, the second recessed area 70 has a diameter D4 of about 211 mm to about 215 mm and a depth X2 of about 5.5 mm to about 9.7 mm. In another embodiment, the first recessed area 46 has a diameter D4 of about 213 mm and a depth X1 of about 7.6 mm.
Turning now to
When placed in the second recessed area 70, the second seal 95 is positioned such that the inner opening 96 of the second seal 95 is aligned with the opening of the cylinder 16. For example, second seal 95 may be a self-centering seal 110 with an outer edge 116 having an outer diameter 118 (e.g., D9) that is less than diameter Dc and a plurality of centering tabs 130 provided around the outer edge 116 such that the second seal 95 self-centers around the opening of the cylinder 16 in the manner described above with regard to the self-centering seal 110. The surface 98 of the second seal 95 is placed against the second bottom surface 74 of the second recessed area 70.
As shown in
The second insert 78 has a thickness T2 and an outer diameter D5 (see
In yet another embodiment, the second insert 78 may have a sealing material such as rubber, bonded to its bottom surface 86 using techniques knowing in the art for bonding materials such as rubber to metal, effectively forming a combined second insert 78 and second seal 95. The combined second seal 95 and second insert 78 could then be placed into the first recessed area 70 in a single step.
The outer diameter D5 of the second insert 78 is configured to allow the second insert 78 to fit securely within the second recessed area 70 and overlap the first insert 50 the radial distance DR. Thus, the outer diameter D5 of the second insert 78 is matched to the second recessed area 70. For example, where an interference fit is used to secure the second insert 78 in the second recessed area 70, the diameter D5 of the second insert 78 is configured to be slightly larger than the diameter D4 of the second recessed area 70. In one embodiment, the second insert 78 has a diameter D5 about 0.044 mm to about 0.084 mm greater than the diameter D4 of the second recessed area 70, and preferably about 0.064 mm greater.
The first insert 50 and the second insert 78 may be made from stainless steel, or any other useful material, and may include a substantially uniform thickness. In the depicted embodiment, while not illustrated, it will be understood that after positioning the first insert 50 and the second insert 78 within the first and second recessed areas 46, 70, respectively, a machining tool may be used to plane the surface of the top deck 18, thus removing any excess portions of the first insert 50 and second insert 78. Such a procedure may ensure a substantially planar surface of the top deck 18 after the first insert 50 and the second insert 78 have been positioned within the first and second recessed areas 46, 70, respectively.
Moreover, prior to placing the first insert 50 and second insert 78, a chemical adhesive (e.g. RTV®, LOCTITE®) may be applied to the inserts or to the recessed areas 46, 70, respectively. This may be done in addition to, or in lieu of an interference fit.
In yet another exemplary embodiment, a seal 90, 95 may in certain instances only be placed under one of the first insert 50 or second insert 78 and not under the other. For instance, the recessed area 70 may be formed around the cylinder opening 16, the seal 95 may be placed on the bottom surface 74 of the recessed area 70, and the insert 78 positioned in the recessed area 70 against the seal 95. If inserts 50 are placed around fluid passages 22, in this instance, they may not have seals 90 placed in the recessed areas 46. Dependent on the extent of the cracks in the top surface 18 of the engine, it may not be necessary for the first and second inserts 50, 78 to overlap.
Similarly, a recessed area 46 may be formed around a fluid passage, a seal 90 may be placed on the bottom surface 48 of the recessed area 46, and an insert positioned in the recessed are 46 and against the seal 90. If insert 78 is placed around the cylinder 16, in this instance, they may not have seals 95 placed in the recessed area 70.
The present disclosure finds potential applicability to any engine block that may be subject to operational loads causing cracks and/or wear. Further, the disclosure may be specifically applicable to engine blocks having cracks radiating from cylinder bores and extending across a top deck of the engine block. Yet further, the present disclosure may be applicable to fluid passages surrounding such cylinder bores that may be subject to general wear and/or erosion. Although the disclosure describes the remanufacture, or repair, of such engine blocks, the method described herein may also be used during manufacture to reduce the occurrence of such cracks and/or wear during operation.
During remanufacture, or repair, the engine block 10 may be inspected for cracks, such as by visual inspection or using a magneflux check or other known means. Cracks, such as cracks 30, 34, 36, and 38, may be discovered during the inspection. Additionally, one or more of the fluid passages 22 may exhibit wear and/or erosion around the openings thereof, along the top deck 18 of the engine block 10. To repair the engine block 10, as shown in
It will be understood that the engine block 10 may include multiple top decks (such as with a Vee-style engine), multiple cylinder bores 16, and multiple fluid passages 22. Thus, the manufacturing method 40 may include creating multiple first recessed areas 46 and second recessed areas 70 and using multiple first inserts 50, first seals 90, second inserts 78, and second seals 95 in corresponding recessed areas. A plurality of first and second inserts 50, 78, and first and second seals 90, 95 may be packaged together as a repair kit for a predetermined engine.
First seals 90 and second seals 95 should not overlap into the fluid passage 22 or cylinder 16. To assure that the inner opening 92 of the first seal 90 is centered about the fluid passage 22, self-centering seals 110 as described above may be used to assure that the seal does not overlap the fluid passage 22 or the cylinder 16. By not having to use centering tools to assure the seals are properly centered, manufacturing time may be reduced when placing inserts. Moreover, any counterbore 150 that needs sealing at the bottom surface 158 could benefit from the use of a self-centering seal 110 to reduce installation time and the need for additional tools.
It should be appreciated that cracks, such as cracks formed within or radiating from the first and second recessed areas 46, 70, may occur after repair. The presently disclosed method 40, as described herein, may be repeated to repair such cracks. Specifically, the first and second inserts 50, 78 and first and second seals 90, 95 may be removed, such as by creating one or more threaded bores within the inserts 50, 78 to attach a removal tool, and the additional cracks and/or wear occurring near the cylinder bore 16 and fluid passages 22 may be machined out. However, the recessed areas 46, 70 may be enlarged only an amount sufficient to remove most of the cracks and/or wear, without interfering with other structures or components of the engine block 10. As such, the engine block 10 may be limited to a finite number of repairs. After the additional engine block material has been removed, an appropriately dimensioned inserts 50, 78, and seals 90, 95 may be placed and press fit within the corresponding recessed areas 46, 70.
The presently disclosed method may provide an effective means for repairing cracks and/or wear occurring within an engine block, particularly at or near a cylinder bore and surrounding water passages. Alternatively, the present disclosure may be implemented during manufacture of an engine block to reduce the occurrence of such cracks and/or wear.
It should be appreciated that the disclosed method may be used on other openings in the engine block.
It should be understood that the above description is intended for illustrative purposes only, and is not intended to limit the scope of the present disclosure in any way. Thus, those skilled in the art will appreciate that other aspects of the disclosure can be obtained from a study of the drawings, the disclosure and the appended claims.
