US20160010546A1

US20160010546A1 - Rocker cover assembly for engines

Info

Publication number: US20160010546A1
Application number: US14/859,359
Authority: US
Inventors: Amar J. Nivarthi
Original assignee: Electro Motive Diesel Inc
Current assignee: Progress Rail Locomotive Inc
Priority date: 2015-09-21
Filing date: 2015-09-21
Publication date: 2016-01-14
Also published as: CN206054023U; US9771970B1; US20170080751A1; US9636949B2

Abstract

A rocker cover assembly for an engine is disclosed. The rocker cover assembly includes a base member, a cover plate, and at least one fastener unit that attach the cover plate to the base member. The base member includes fastener-receiving portions, each of which has a step between a first section and a second section. The second section includes an insert-receiving portion. The cover plate includes fastener holes axially aligned with the fastener-receiving portions of the base member. Each fastener unit includes a retaining insert, a push nut, and a threaded fastener. The retaining insert is fixedly attached to the insert-receiving portion. The push nut is co-axially positioned with the bore within the first section and against the step, to limit a travel of the push nut towards the second section. The threaded fastener includes a head section, a threaded section, and an extended shank section.

Description

TECHNICAL FIELD

The present disclosure relates generally to fastener units for a rocker cover assembly of an engine. More specifically, the present disclosure relates to a fastener unit that facilitates removable attachment between a cover plate and a cover body of the rocker cover assembly, such that the fastener unit is retained with the cover plate upon a disassembly of the cover plate from the rocker cover assembly.

BACKGROUND

Engines, such as internal combustion engines, are commonly known to employ a rocker cover assembly that houses various engine components, such as a rocker arm, a rocker shaft, intake valves, and exhaust valves. Rocker cover assemblies generally include a cover body, a cover plate, and a number of threaded fasteners that facilitate a removable attachment of the cover plate to the cover body of the rocker cover assembly.
In conventional rocker cover assemblies, the threaded fasteners extend through the cover plate and engage with a threaded bore of the cover body. This enables the cover plate to be attached to the cover body of the rocker cover assembly. Notably, the threaded fasteners are generally made of steel and the cover body is generally made of aluminum. Different material for both of the threaded fastener and the base member may cause wear and tear of the threaded bore of the cover body. This results in a relatively less reliable assembly of the threaded fastener with the cover body and the cover plate.
Furthermore, during several events of an engine repair and service, the cover plate needs to be disassembled from the cover plate to access an inside of the rocker cover assembly and the components (rocker shaft, rocker arm) assembled within the rocker cover assembly. Generally, the cover plate is removed by loosening the threaded fasteners from the threaded bore and by altogether removing the threaded fasteners from the cover body and the cover plate. In such situations, if the threaded fasteners are neglected and dropped out of sight, the threaded fasteners are likely to be lost, which incurs additional effort in the recovery of the threaded fasteners. Given a failed recovery attempt, new threaded fasteners are procured, which adds to the burden of cost and effort incurred in the engine's service, and an increased machine downtime.
U.S. Pat. No. 3,777,358 discloses a retained fastener assembly that includes a screw to secure a pair of panels. Although, this reference discloses a retaining ring, which is slideably positioned along a shank of the screw and prevent a withdrawal of the screw from one of the panels, the retaining ring may displace radially from a line of action of the screw during an assembly of the screw on the pair of side panels. This results in a faulted assembly of the retained fastener assembly on the pair of panels.

SUMMARY OF THE INVENTION

Various aspects of the present disclosure are directed towards a rocker cover assembly for an engine. The rocker cover assembly includes a base member, a cover plate, and at least one fastener unit. The fastener unit is used to removably attach the cover plate to the base member. The base member includes a service window and a number of fastener-receiving portions structured on the service window. Each fastener-receiving portion includes a bore, which defines a first section, a second section, and a step. The step is disposed between the first section and the second section. The second section includes an insert-receiving portion. The cover plate includes a plurality of fastener holes axially aligned with the plurality of fastener-receiving portions of the base member. The fastener unit removably attaches the cover plate to the service window of the base member. The fastener unit includes a retaining insert, a push nut, and a threaded fastener. The retaining nut is fixedly conformable within the insert-receiving portion. The push nut is co-axially positionable with the bore within the first section. The push nut is further positioned against the step, to limit a travel of the push nut towards the second section. The threaded fastener includes a head section, a threaded section, and an extended shank section between the head section and the threaded section. During assembly, the threaded fastener axially passes through at least one of the plurality of fastener holes and is movable through the push nut, along an engagement direction, and retained with the cover plate. The threaded fastener further moves in the engagement direction, to threadably engage with the retaining insert.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of a portion of an engine that illustrates multiplicity of rocker cover assemblies for the engine;

FIG. 2 is an enlarged perspective view of one of the rocker cover assemblies of FIG. 1, in accordance with the concepts of the present disclosure; and

FIG. 3 is an exploded perspective view of the rocker cover assembly of FIG. 2, in accordance with the concepts of the present disclosure.

FIG. 4 is a cross-sectional view of a portion of the rocker cover assembly taken along a section 4-4 of the rocker cover assembly of FIG. 2, in accordance with the concepts of the present disclosure; and

FIG. 5 is a perspective view of a portion of the rocker cover assembly of FIG. 3, with a base member disassembled from the cover assembly.

DETAILED DESCRIPTION

Referring to FIG. 1, there is shown an engine 10. Although not limited to, the engine 10 may be one of a spark ignition type and/or a compression ignition type. Other engine types may also be contemplated. Exemplarily, the engine 10 includes six in-line cylinders 12, each of which includes various mechanical components (not shown) arranged to perform one or more functions associated with the engine 10. The mechanical components (not shown) may include, but are not limited to, an intake valve, an exhaust valve, a rocker arm, and a rocker shaft. Additionally, the engine 10 employs six rocker cover assemblies 14, which co-relate to each of the six cylinders 12, and each of which is adapted to cover and protect the mechanical components (not shown) of each of the six cylinders 12 of the engine 10. More specifically, a rocker cover assembly 14 is mounted onto an engine block 16, such that the rocker cover assembly 14 covers the mechanical components (not shown) of a cylinder 12 of the engine 10. Although, the present disclosure describes the engine 10 with the six cylinders 12 and the six associated rocker cover assemblies 14, a varied number of cylinders 12 and associated rocker cover assemblies 14 may be contemplated. Application of the concepts of the present disclosure to a singular cylinder 12 and associated a singular rocker cover assembly 14 may also be contemplated.
Referring to FIG. 2, there is shown a singular rocker cover assembly 14 of the engine 10. The rocker cover assembly 14 houses lubricant oil to facilitate lubrication of these mechanical components (not shown). The rocker cover assembly 14 includes a base member 18, a cover plate 20, and four fastener units 22. The fastener units 22 removably attach the cover plate 20 to the base member 18 of the rocker cover assembly 14.
Referring to FIGS. 2 and 3, the base member 18 is attached to the engine block 16, to facilitate mounting of the rocker cover assembly 14 onto the engine block 16. An attachment between the base member 18 and the engine block 16 may be facilitated by, but is not limited to, an adhesive attachment, a weld attachment, a bolt attachment, and/or a rivet attachment. The base member 18 is a body of the rocker cover assembly 14 that includes a service window 24, which facilitates access to the mechanical components (not shown) of the engine 10, during service and repairs. Additionally, four fastener-receiving portions 26 are structured adjacent to the service window 24 to allow the fastener units 22 to fasten the cover plate 20 with the base member 18. Generally, the base member 18 is a hollow hood structure generally made of casted aluminum material. Other materials for the base member 18 may be contemplated.
The cover plate 20 is generally an aluminum plate that covers the service window 24 of the base member 18. The cover plate 20 includes four fastener holes 38. When applied, the cover plate 20 is positioned against the base member 18 such that the four fastener holes 38 of the cover plate 20 are axially aligned with the four fastener-receiving portions 26 of the base member 18. This arrangement enables the fastener units 22 to engage the cover plate 20 with the base member 18.
Referring to FIG. 3, the fastener units 22 facilitate a removable attachment of the cover plate 20 to the service window 24 of the base member 18. More specifically, each of the four fastener units 22 are adapted to extend through the four fastener holes 38 of the cover plate 20 and engage with the fastener-receiving portion 26 of the base member 18, to removably attach the cover plate 20 to the base member 18. The present disclosure describes four fastener-receiving portions 26, four fastener holes 38, and the associated four fastener units 22, to attach the cover plate 20 to the base member 18. However, use of a varied number of fastener-receiving portions 26, a varied number of fastener holes 38, and a varied number of fastener units 22, to attach the cover plate 20 to the base member 18, may be contemplated. The fastener unit 22 includes a retaining insert 40, a push nut 42, and a threaded fastener 44.
Referring to FIG. 4, an inner profile of each fastener-receiving portion 26 amongst the four fastener-receiving portions 26 is discussed. More particularly, a cross-section of a portion of the rocker cover assembly 14, taken along a section 4-4′ (FIG. 2), is depicted. Also shown is a cross-sectional profile of the fastener unit 22 disposed across one of the fastener holes 38 and one of the fastener-receiving portions 26. For ease in understanding, an exclusive arrangement of a singular fastener unit 22, relative to a bore 28 of the singular fastener-receiving portion 26 and a singular fastener hole 38, of the cover plate 20. Therefore, similar arrangements for the remaining fastener-receiving portions 26 relative to the remaining fastener holes 38 and the remaining fastener units 22 are envisioned.
The bore 28 defines a first section 30 and a second section 32. The first section 30 is defined relatively adjacent to the service window 24, while the second section 32 is defined farther away from the service window 24, and further into the base member 18. The second section 32 has a relatively smaller inner diameter than the first section 30. Therefore, a step 34 is defined between the first section 30 and the second section 32. The second section 32 includes an insert-receiving portion 36.
Referring again to FIGS. 3 and 4, the retaining insert 40 of the fastener unit 22 is generally a steel insert fixedly attached to the insert-receiving portion 36 of the bore 28. As a general practice, the retaining insert 40 is press-fitted into the insert-receiving portion 36, although other forms of assemblage are possible. The retaining insert 40 is coaxially positioned in the insert-receiving portion 36 of the bore 28. Further, the retaining insert 40 includes internal threads, which facilitate an engagement of the retaining insert 40 to the threaded fastener 44 of the fastener unit 22.
The push nut 42 is co-axially positioned with the bore 28 of the fastener-receiving portion 26. More specifically, the push nut 42 is positioned within the first section 30 of the bore 28. The push nut 42 is further positioned against the step 34, to limit a travel of the push nut 42 towards the second section 32, when assembled. In an embodiment, the push nut 42 includes a number of flexible sections (not shown), which allow a unidirectional movement of the threaded fastener 44 in an engagement direction, C. This direction is defined when the threaded fastener 44 is pushed into the fastener hole 38 and further drawn into the bore 28, so as to be eventually threadably fastened with the retaining insert 40. This arrangement limits the movement of the threaded fastener 44 in a direction opposite to the engagement direction, C, unless the threaded fastener 44 is loosened. In an assembled state of the rocker cover assembly 14, the push nut 42 is axially disposed within the fastener hole 38 and substantially loosely disposed about an intermediate section of the threaded fastener 44.
The threaded fastener 44 is a steel bolt that includes a head section 46, a threaded section 48, and an extended shank section 50. The extended shank section 50 is defined as the intermediate section of the threaded fastener 44, defined between the head section 46 and the threaded section 48. The threaded section 48 of the threaded fastener 44 includes external threads meshable with the internal threads of the push nut 42. This allows for threadable engagement with the retaining insert 40 of the fastener unit 22, as noted above. Moreover, this facilitates a removable attachment of the cover plate 20 to the base member 18.
Referring to FIG. 5, there is shown a disassembled state of the rocker cover assembly 14. In the disassembled state of the rocker cover assembly 14, the threaded fastener 44 is unthreaded from the retaining insert 40 of the fastener unit 22. This allows the threaded fastener 44 to move in a direction opposite to the engagement direction, C (FIG. 4) and be removed from the base member 18. In so doing, the cover plate 20 is detachable from the base member 18. However, as the push nut 42 restricts the movement of the threaded fastener 44 in a direction opposite to the engagement direction, C, relative to the cover plate 29, the threaded fastener 44 retains engagement with the cover plate 20 in the disassembled state of the rocker cover assembly 14.

INDUSTRIAL APPLICABILITY

In operation, to facilitate an assembly of the cover plate 20 to the service window 24 of the base member 18, an operator positions the push nut 42 in the first section 30 of the bore 28 of the base member 18. As the first section 30 includes the step 34, the push nut 42 is suitably seated within the step 34 so as to be co-axially disposed relative to the bore 28. Thereafter, the operator positions the cover plate 20 over the service window 24 so as to define a co-axial relationship between each of the fastener holes 38 and fastener-receiving portions 26. The threaded fastener 44 is then pushed in the engagement direction, C, into the first section 30 of the bore 28. As a result, the threaded section 48 passes across the first section 30 and is drawn through the push nut 42. As the push nut 42 is positioned against the step 34 of the bore 28, the push nut 42 is substantially retained in position, while the threaded fastener 44 is moves through the push nut 42 in the engagement direction, C, and progresses into the second section 32 of the base member 18. Additionally, during such a passage, the flexible sections (not shown) of the push nut 42 ensures that the threaded section 48 is adequately prevented from damage. Such an arrangement facilitates a relative ease and reliable installation of the threaded fastener 44 onto the rocker cover assembly 14. Once the threaded section 48 passes across the push nut 42, the push nut 42 assumes a disposal within the extended shank section 50 of the threaded fastener 44.
Furthermore, once the threaded section 48 is drawn into the retaining insert 40, the operator rotates the threaded fastener 44 to drive the threaded section 48 of the threaded fastener 44 to the retaining insert 40 of the fastener unit 22. As both of the threaded fastener 44 and the retaining insert 40 are made of steel, the internal threads of the retaining insert 40 are not damaged, during assembly of the threaded fastener 44 to the retaining insert 40. This facilitates a reliable assembly of the fastener unit 22 to the base member 18 and the cover plate 20.
Furthermore, at the time of service and/or repair events of the engine 10, the cover plate 20 is disassembled from the base member 18 of the rocker cover assembly 14. To facilitate a disassembly of the cover plate 20 from the base member 18, the operator loosens the threaded fastener 44 from the retaining insert 40 of the fastener unit 22. Once loosened, the operator moves the threaded fastener 44 in a direction opposite to the engagement direction, C. As a result, the cover plate 20 is disengaged from the service window 24. However, as the push nut 42 restricts a movement of the threaded fastener 44 in the direction opposite to the engagement direction, C, relative to the cover plate 20, the threaded fastener 44 is retained with the cover plate 20 (as shown in FIG. 5). This eliminates the likelihood of the threaded fastener 44 being lost during service and/or repair events.
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 may be obtained from a study of the drawings, the disclosure, and the appended claim.

Claims

What is claimed is:

1. A rocker cover assembly for an engine, the rocker cover assembly comprising:

a base member including a service window and a plurality of fastener-receiving portions structured on the service window, each of the plurality of fastener-receiving portions including:

a bore defining a first section, a second section, and a step, the step being disposed between the first section and the second section, wherein the second section includes an insert-receiving portion;

a cover plate including a plurality of fastener holes, wherein the plurality of fastener holes are axially aligned with the plurality of fastener-receiving portions of the base member;

at least one fastener unit, the at least one fastener unit being adapted to removably attach the cover plate to the service window of the base member, each of the at least one fastener unit including:

a retaining insert fixedly conformable within the insert-receiving portion of the bore;

a push nut co-axially positionable with the bore within the first section and against the step to limit a travel of the push nut towards the second section; and

a threaded fastener with a head section, a threaded section, and an extended shank section therebetween,

wherein during an assembly the threaded fastener is axially passed through at least one of the plurality of fastener holes and is movable through the push nut to be retained with the cover plate and being further movable to threadably engage with the retaining insert, along an engagement direction.