GROMMET AND GROMMET ASSEMBLY FOR MACHINE FLUID SYSTEM

Description

TECHNICAL FIELD

The present disclosure relates generally to a fluid system in a machine, and more particularly to a grommet and grommet assembly for an engine aftertreatment system.

BACKGROUND

A great many fluid systems are used in machines ranging from fuel systems to lubrication systems, temperature control systems and many others. One known fluid system used for controlling certain internal combustion engine emissions is coupled to the machine's exhaust system and delivers a reductant for catalytic reduction of nitrogen oxides. In one typical system, a fluid reductant, commonly referred to as diesel exhaust fluid (DEF) or by similar terms, includes a urea-based aqueous solution that is injected into a stream of exhaust gas from the internal combustion engine upstream of a catalytic reduction module. The injected DEF produces ammonia that reacts to reduce nitrogen oxides in the exhaust at a catalyst according to well-known pathways to produce nitrogen gas and water.

Various reductant delivery systems are known and used in a number of different machine applications, notably mobile vehicles in the nature of off-highway machinery and on-highway trucks. The machine carries a fluid tank storing reductant, commonly DEF as noted above, which is delivered in prescribed amounts to the engine exhaust system. It is common for the tank in reductant delivery systems of this general type to be refilled with DEF periodically, and not uncommonly as much as once per day depending on the manner and extent to which the machine is operated. One known diesel engine exhaust aftertreatment system is set forth in co-pending U.S. patent application Ser. No. 18/103,958 to Bodedda et al, filed Jan. 21, 2023. Recognizing the ever-evolving nature of technical and commercial challenges, there is always room for improvements and development of alternative strategies.

SUMMARY

In one aspect, a fluid system for a machine includes a tank, a header piece, a sock filter, and a grommet connected to the sock filter. The grommet includes a skirt portion made at least in part of a first material, and a flange portion made at least in part of a second material, with the second material being less compressible than the first material. The grommet further includes a plurality of bolt holes formed within the flange portion, formed at least in part by the second material.

In another aspect, a grommet assembly for an engine aftertreatment system includes a sock filter and a grommet connected to the sock filter. The grommet includes a skirt portion made of a first material, a carrier attached to the skirt portion and made of a second material, and a plurality of bolt holes formed in the carrier.

In yet another aspect, a grommet includes a skirt portion made at least in part of a skirt material, and a carrier made at least in part of a second material more resistant to deformation than the skirt material. The grommet further includes a plurality of bolt holes formed in the carrier, and formed at least in part by the second material.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a side diagrammatic view of a machine, according to one embodiment;

FIG. 2 is a diagrammatic view of a grommet assembly for a fluid system, according to one embodiment;

FIG. 3 is an enlarged view of a portion of the grommet assembly of FIG. 2;

FIG. 4 is a perspective view of a grommet, according to one embodiment;

FIG. 5 is an enlarged view of a portion of the grommet;

FIG. 6 is a perspective view of a portion of the grommet;

FIG. 7 is a side view of the grommet;

FIG. 8 is a sectioned view of the grommet;

FIG. 9 is a perspective view of a grommet, according to another embodiment;

FIG. 10 is a perspective view of a grommet, according to yet another embodiment;

FIG. 11 is a perspective view of a grommet, according to yet another embodiment.

DETAILED DESCRIPTION

Referring to FIG. 1, there is shown a machine 12 according to one embodiment, and including a frame 14 and a cab 16 supported on frame 14. Machine 12 includes a plurality of ground-engaging elements 18, in the illustrated case ground-engaging wheels. Machine 12 also includes an internal combustion engine 20, such as a compression-ignition diesel engine, coupled with an exhaust system 28. A temperature control system 22 is provided and includes a radiator 24 mounted at a front end of frame 14. Machine 12 is shown in the context of a mining truck, however, the present disclosure is not thereby limited and a variety of on-highway or off-highway machines 12 could benefit by application of the present disclosure, including trucks, tractors, excavators, backhoes, and many others. Machine 12 is also not limited to a mobile machine application, and could be a stationary machine application such as a generator set or genset, a compressor, a pump, or still others.

Machine 12 also includes a fluid system 26 coupled with exhaust system 28 and also with temperature control system 22. Fluid system 26 can include a diesel emission fluid (DEF) system structured to provide a reductant in a liquid form to exhaust system 28 for delivery by way of a DEF admission valve or injector 30 in a generally known manner. No specific type of fluid reductant, or even application strictly to a DEF system at all, is intended by way of the present description. Fluid system 26 also includes a tank 32 structured to store DEF. Fluid conduits (not numbered) extend between tank 32 for conveying a temperature control fluid, such as engine coolant, between tank 32 and radiator 24 or other elements of temperature control system 22. A separate fluid connection can extend between tank 32 and DEF injector 30.

Now also referring to FIGS. 2 and 3, fluid system 26 may also include a plurality of manifold assemblies 34 positioned at least partially within tank 32. Each manifold assembly 34 hereinafter may be referred to in the singular. Manifold assembly 34 includes a tube assembly 36, and a plug 38 such as an electrical plug for establishing data and electrical power communications between manifold assembly 34 and an onboard electrical system in machine 12. It should be appreciated that the tube assembly 36 composition and arrangement could differ significantly from that disclosed and illustrated. In other instances, a different number of tubes, a different shape of tubes, or different functional purposes than those described could be employed. Manifold assembly 34 further includes a header piece and a plurality of fluid connectors 40 mounted to header piece 41.

Manifold assembly 34 also includes a sock or sock filter 42 enveloping tube assembly 36. A variety of sock filters are known and commercially available. Sock filter 42 has a flexible form generally akin to a sock or a bag, and can be slipped over one end of tube assembly 36 and secured near or at an opposite end of tube assembly 36 to filter debris and particulates from DEF stored in tank 32 prior to delivery to DEF injector 30. It has been observed in certain earlier systems that the filters may become impermeable when submerged or exposed to application fluids, creating an airtight barrier between the tank 32 volume outside of sock filter 40 and the internal volume within the filter, leading to the entrapment of air, the formation of bubbles, and “gassing” the fuel. Fluid system 26 may further include a grommet 44 and grommet assembly of grommet 44 and sock filter 42 positioned between header piece and manifold assembly 34. Sock filter 42 may be attached directly to grommet 44 such as by stitching or any other suitable connection strategy. Grommet 44 may be bolted between manifold assembly 34 and header piece 41 using a plurality of bolts, typically each installed to apply a bolting load to sandwich grommet under compression between manifold assembly 34 and header piece 41.

Now also referring to FIG. 4, grommet 44 may include a one-piece body, also shown generally via numeral 44, formed by injection molding or compression molding, for example, or a part produced by alternative molding and/or forming techniques. The one-piece body may include two or more than two parts that are irreversibly connected, and formed from suitable materials discussed further herein. Over-molding or co-injection molding of multiple pieces may be employed. In other embodiments, grommet 44 may be formed by attaching multiple separate pieces independently of the molding process. Grommet 44 may include a skirt portion 46 including a first piece 48 defining a skirt axis 50. Hereafter, the terms “skirt” and “skirt portion” are used, at times, interchangeably. Skirt 46 may include an outer skirt surface 52 and an inner skirt surface 54 positioned radially outward of skirt axis 50, forming an opening 56, and a peripheral skirt surface 58. Skirt 46 may be made of a first material or a “skirt material 60”. The first material may include a rubber or a rubber-like material, such as natural rubber or any suitable synthetic rubber, or a material otherwise exhibiting generally known rubber-like properties of resilience, elasticity, hardness, compressibility, chemical resistance, etc.

Grommet 44 may further include a plurality of vents 62 formed in skirt 46, structured to traverse through inner skirt surface 54 and outer skirt surface 52. Each of the plurality of vents 62 may include a plurality of perforations, for example formed in a metallic screen, to facilitate ventilation. It should be understood that vents 62 within the present disclosure may vary in number and/or arrangement contingent upon ventilation requirements. For example, there may be no requirement for vents 62 in some instances or the need for ventilation satisfied by only a single vent. In other examples, there may be at least two vents 62 of finite number.

Grommet 44 further includes a flange portion 64 including a second piece 66 attached to first piece 48. Flange portion 64 may include a carrier 68 which is irreversibly attached to skirt 46 by an interlocking mechanical attachment and an adhesive attachment, discussed further subsequently. Carrier 68 may have an annular shape and includes a peripheral carrier surface 70 spanning around skirt axis 50. Flange portion 64 is designed to establish a rigid connection among header piece 41, grommet 44, and manifold assembly 34 and includes material properties assisting in maintaining a bolting load over time, as further discussed herein.

To this end, carrier 68 may be made at least in part of a second material or a carrier material 71, being less compressible than skirt material 60. Examples of a second material may include a suitable plastic, a metallic material, a composite material, and various other non-rubber materials, more rigid, harder, and more resistant to compression and/or other forms of deformation than skirt material 60. Variability in the composition of grommet 44 material is contemplated within the present disclosure. For example, grommet 44 may be formed uniformly of the second material, provided it maintains the capacity to provide a rigid connection maintaining bolting load as alluded to above. The second material may also be understood to be relatively more set-resistant than the first material in response to a bolting load. Put differently, when carrier 68 is bolted in place for service, the second material forming carrier 68 may be less apt to “take a set” by way of plastic deformation in response to a bolting load over time than skirt material 60, as further discussed herein.

Referring to FIGS. 5 and 6, grommet 44 further includes a plurality of bolt holes 72 formed within carrier 68. Each bolt hole 72 defines a bolt axis 74 oriented parallel relative to skirt axis 50, and further includes an inner bolt hole surface 76 extending around each bolt axis 74. The plurality of bolt holes 72 may be arranged annularly within carrier 68, and may be formed at least in part by the second material. Accordingly, in some embodiments inner bolt surface 76 may also be formed in part by skirt material 60 and in part by the second material. In a refinement, a minority of each respective inner bolt surface 76 is formed by skirt material 60, and a majority of each respective inner bolt surface 76 is formed by the second material. In yet other embodiments, inner bolt surface 76 may be formed entirely by the second material. The usage of “first material” or “skirt material” and “second material” or “carrier material” in the context of the present disclosure do not establish strict definitions; rather, they are used to differentiate between the material used for skirt portion 46 and the material used for flange portion 64.

Grommet 44 further includes a plurality of notches 78 formed within flange portion 64. The number and arrangement of notches 78 corresponds to the number of bolt holes 72, and the position of each notch 78 aligns with, and in part defines, a respective bolt hole 72. Various configurations of notches 78 are within the scope of the present disclosure. For example, notches 78 may be wholly formed within flange portion 64. In another example, notches 78 may be formed in part in skirt portion 46 and in part within flange portion 64. In any case, notches 78 may be formed at least in part from the same material as flange portion 64.

Now referring to FIGS. 7 and 8, as suggested above, carrier 68 and skirt 46 are attached by a tongue-in-groove connection 80. To this end, skirt 46 further includes an annular protrusion 82 forming a mating groove 84. Mating groove 84 may be positioned on peripheral skirt surface 58 and annularly extends around skirt portion 46. Carrier 68 includes a tongue 86 extending along peripheral carrier surface 70 and designed to engage complementarily in mating groove 84. Grommet 44 may further include an adhesive attachment 88 to reinforce the tongue-in-groove connection 80. In other embodiments, the tongue-in-groove connection might be reversed, with a groove formed in carrier 68 and a tongue formed by skirt 46. The connection between the respective parts may be irreversible. “Irreversible” means the connection cannot be reversed without deformation or damage to the connected parts. When tongue 86 is positioned within mating groove 84, adhesive attachment 88 may be interposed between the abutting surfaces of skirt 46 and carrier 68.

A suitable adhesive may be coated upon surfaces of carrier 68 that are to be connected to skirt 46 prior to molding carrier 68 and skirt 46 together. In one embodiment, carrier 68 is made first, then coated with an adhesive and placed in an injection mold. Then the material to form skirt may be injected and the composite part removed once molding is complete. Other strategies and methods for attaching carrier 68 and skirt 46 might include mechanical fasteners, concurrent co-molding of both parts, additive manufacturing, or still others.

Referring now to FIG. 9, there is shown a grommet 144 according to another embodiment. Grommet 144 may be structured in many ways similarly or identically to grommet 44 discussed above, and the foregoing description of grommet 144 should be understood to refer to grommet 144 except where otherwise indicated or apparent from the context. Grommet 144 may include a plurality of skirt portion extensions 145 radially spaced about a skirt axis 156. In contrast to grommet 44, grommet 144 includes bolt holes 172 within each extension 145. Extensions 145 may be formed of a skirt material 160, provided that when installed for service bolting loads are reacted by material that surrounds bolt holes 172 rather than the material actually forming bolt holes 172. The material surrounding bolt holes 172 may be analogous to the second material or carrier material discussed above, and skirt material 160 analogous to the first material or the skirt material discussed above.

Referring now to FIG. 10, there is shown another grommet 244 according to another embodiment. In a manner similar to grommet 144, grommet 244 may also be structured generally akin to grommet 44 discussed above, and the foregoing description of grommet 44 should also be understood to refer to grommet 244 except where otherwise specified. Within the context of the present embodiment skirt 246 may be formed uniformly of a skirt material 260 and carrier 268 may be formed uniformly of a carrier material. Bolt holes (not numbered) in carrier 268 may be formed entirely by the carrier material.

Referring now to FIG. 11, there is shown yet another grommet 344 according to another embodiment. In a manner similar to grommets 144 and 244, grommet 344 may also be structured akin to grommet 44 discussed above, and the foregoing description of grommet 344 should also be understood to refer to grommet 44 except where otherwise specified. In contrast to grommet 44, grommet 344 may be made from skirt material 360 but includes a plurality of inserts 361 formed of a second material and forming a plurality of bolt holes.

INDUSTRIAL APPLICABILITY

Referring to the drawings generally, it will be recalled that a grommet according to the present disclosure can be installed in an engine aftertreatment system in the field. A service technician could receive a suitable grommet or grommet assembly of a grommet and sock, sold as an aftermarket part, and swap out the new grommet and/or grommet assembly for a used part. The fluid system can then be inspected, reassembled, and returned to service. In other instances, the present disclosure can be implemented with grommets and/or grommet assemblies according to the present disclosure sold as part of original equipment in a fluid system or a machine ready for initial placement in service in the field.

As noted above, material forming parts of a grommet according to the present disclosure, including the bolt holes or surrounding areas of the bolt holes may be relatively more rigid, harder, and relatively more set-resistant than material forming other parts of the grommet. It has been observed that when a grommet flange is bolted in place for a period of time, relatively less rigid materials can “take a set” under a bolting load. The phenomenon can be understood as the flange being squished down under load, and eventually plastically deforming to a more squished down state than a starting state. As a result, the reduced springiness of the material can cause the bolts to loosen, potentially risking damage or performance degradation to the fluid system. According to the present disclosure, the use of more rigid, potentially harder, and relatively more set-resistant materials responsive to a given bolting load can address such concerns.

The present description is for illustrative purposes only, and should not be construed to narrow the breadth of the present disclosure in any way. Thus, those skilled in the art will appreciate that various modifications might be made to the presently disclosed embodiments without departing from the full and fair scope and spirit of the present disclosure. Other aspects, features and advantages will be apparent upon an examination of the attached drawings and appended claims. As used herein, the articles “a” and “an” are intended to include one or more items, and may be used interchangeably with “one or more.” Where only one item is intended, the term “one” or similar language is used. Also, as used herein, the terms “has,” “have,” “having,” or the like are intended to be open-ended terms. Further, the phrase “based on” is intended to mean “based, at least in part, on” unless explicitly stated otherwise.