Fuel system components and method of fabricating the same

Abstract

A fuel system component is disclosed for use in a fuel system, such as for fuel injectors, fuel cells, fuel pumps, and / or fluid flow control devices. The net shape of the fuel system component is formed from a cold extrusion process as a monolithic, one piece metallic body. The net shape of the fuel system component may include at least one internal passage that is formed by cold extrusion without machining or drilling of the monolithic metallic body.

Description

FUEL SYSTEM COMPONENTS AND METHOD OF FABRICATING THE SAMEFIELD OF THE DISCLOSURE

[0001] The present disclosure generally relates to fuel system components such may be employed in fuel injectors, fuel cells, fuel pumps, and / or fluid flow control devices, and more particularly, to fuel system components manufactured or fabricated using a cold extrusion process.BACKGROUND

[0002] Fuel system components can be employed with fuel injectors, fuel cells, fuel pumps, and / or fluid flow control devices. The fuel system components may be employed as one or more parts in an assembly for devices such as for example, fuel injectors, fuel pumps, fuel cells, and / or fluid flow control devices. Some fuel system components are used in fuel system devices to control the injection and / or flow of fuel under fuel pressure conditions. Therefore, it is desirable that the fabrication of such fuel system components employ materials that are able perform under these conditions while also being capable of fabrication with the desired dimensions, tolerances, roughness, and flatness.

[0003] Fuel system components can be manufactured by machining and assembling pieces of metal material to form the fuel system component with the desired dimensions and finish. The machining process involves fabrication time to be devoted to each fuel system component to be produced along with energy inputs, material waste, and facility cleaning. The machining process may also make it more difficult to control dimensions, tolerances, roughness, and flatness during fabrication, while also ensuring the parts of the fuel system components meet the requirements for perpendicularity and parallelness. In addition, the raw material used for machining the fuel system components can be expensive both in terms of raw material cost and in the subsequent treatment required to provide the desired material hardness. Therefore, there remains a need for further improvement in this area.DISCLOSURE OF ILLUSTRATIVE EMBODIMENTS

[0004] For the purposes of clearly, concisely and exactly describing illustrative embodiments of the present disclosure, the manner, and process of making and using the same, and to enable the practice, making and use of the same, reference will now be made to certain exemplary embodiments, including those illustrated in the figures, and specific language will be used to describe the same. It shall nevertheless be understood that no limitation of the scope of the invention is thereby created and that the invention includes and protects such alterations, modifications, and further applications of the exemplary embodiments as would occur to one skilled in the art.SUMMARY

[0005] Fuel system components according to the present disclosure are manufactured using a cold extrusion process. The cold extrusion process includes extruding a metal blank into a one-piece, monolithic fuel system component having the desired configuration and dimensions for use in a fuel system device, such as for use in fuel injectors, fuel cells, fuel pumps, and / or fluid flow control devices.

[0006] Fuel system components produced according to the present disclosure include dimensional precision and net-shaped features produced at faster speeds with reduced cost, reduced manufacturing time, cleaner work environment, and lower energy consumption as compared to a machining process. Also, the manufacturing tolerances for the fuel system components produced via cold extrusion are closer than in machining processes, and the fuel system component has higher strength due to cold working the material at below the recrystallization temperature. The fuel system component output from the cold extrusion process includes a final surface that requires no machining, grinding, polishing, and / or oxidation process to finish.

[0007] In an embodiment, a method of fabricating a fuel system component for use in association with a fuel system is provided. The method includes forming a monolithic metallic body that corresponds to a net shape of the fuel system component using a cold extrusion process. The monolithic metallic body is formed during the cold extrusion process to extend from a first end to a second end and to include at least one passage extending at least partially through the monolithic metallic body.

[0008] In one embodiment of the present disclosure, an armature is provided, including a monolithic metallic body being extruded as one piece in a cold extrusion process. The monolithic metallic body extends along a longitudinal axis between a first end and an opposite second end. The monolithic metallic body includes a flange at the first end and a shaft extending from the flange. The shaft extends along the longitudinal axis from the flange to the second end of the monolithic metallic body. A passage extends along the longitudinal axis and opens at the first and second ends of the monolithic metallic body.

[0009] In another embodiment of the present disclosure, a method of fabricating an armature for use in actuation of a valve is provided. The method includes a step of forming a monolithic metallic body using a cold extrusion process. The monolithic metallic body is extrudedto include a flange at a first end of the monolithic metallic body, a shaft extending from the flange along the longitudinal axis to an opposite second of the monolithic metallic body, and a passage that extends along the longitudinal axis and opens at the first and second ends of the monolithic metallic body.

[0010] This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used as an aid in limiting the scope of the claimed subject matter. Further embodiments, forms, objects, features, advantages, aspects, and benefits shall become apparent from the following description and drawings.BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The description herein makes reference to the accompanying drawings wherein like numerals refer to like parts throughout the several views, and wherein:

[0012] FIG. l is a schematic diagram of a cold extrusion process to fabricate various fuel system components according to the present disclosure;

[0013] FIG. 2 is a schematic flow diagram of a method for forming various fuel system components using a cold extrusion process according to the present disclosure;

[0014] FIG. 3 is a cross-sectional view of a fuel injector for an internal combustion engine including one or more of the fuel system components of FIG. 1;

[0015] FIG. 4 is a perspective illustrating certain aspects of an armature according to an example embodiment of the present disclosure;

[0016] FIG. 5 is an end elevation view of the armature in FIG. 4;

[0017] FIG. 6 is a longitudinal cross-sectional view of the armature in FIG. 4;

[0018] FIG. 7 is an enlarged, detailed view of a portion of the flange of the armature in FIG. 4;

[0019] FIG. 8 is an enlarged, detailed view of a portion of the passage of the armature in FIG. 4;

[0020] FIG. 9 is a schematic diagram of a cold extrusion process to fabricate an armature according to the present disclosure; and

[0021] FIG. 10 is a schematic flow diagram of a method for forming an armature using a cold extrusion process according to the present disclosure.DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

[0022] In the following detailed description, reference is made to the accompanying drawings which form a part hereof, and in which is shown by way of illustration specific embodiments in which the present disclosure is practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the present disclosure, and it is to be understood that other embodiments can be utilized and that structural changes can be made without departing from the scope of the present disclosure. Therefore, the following detailed description is not to be taken in a limiting sense, and the scope of the present disclosure is defined by the appended claims and their equivalents.

[0023] FIG. l is a schematic diagram of a process for fabricating one or more fuel system components 30, 40, 50, 60, 70 and FIG. 2 is a flow diagram of a method for fabricating the one or more fuel system components 30, 40, 50, 60, 70 using a cold extrusion process according to the present disclosure. FIG. 3 is a detailed cross-sectional illustration of an embodiment of a fuel injector 100 showing an exemplary implementation of the fuel system components 30, 40, 50, 60, 70 in an assembly of a particular fuel injector. FIGs. 4-8 are illustrations associated with an embodiment of fuel system component 30 that is an armature fuel system component 200 in accordance with another aspect of the present disclosure, and FIGs. 9-10 show a cold extrusion process and method for fabricating armature fuel system component 200.

[0024] While the present disclosure describes particular configurations of fuel system components 30, 40, 50, 60, 70, 200 and / or fuel injector 100, one or more of these features described in the present disclosure may be omitted, and other features are not precluded. The fuel system components 30, 40, 50, 60, 70, 200 of the present disclosure can be used on any fuel injector, fuel cell, fuel pump, and / or fluid flow control device compatible with the features of the present disclosure.

[0025] In an embodiment of the present disclosure, a method 90 of fabricating a fuel system component 30, 40, 50, 60, 70, 200 for use in association with a fuel system 101 is provided. The method 90 includes a step 94 of forming a monolithic metallic body 32, 42, 52, 62, 72, 202 that corresponds to the net shape of the fuel system component 30, 40, 50, 60, 70, 200 using a cold extrusion process. The monolithic metallic body 32, 42, 52, 62, 72, 202 is formed during the cold extrusion process to extend from a first end 34, 44, 54, 64, 76, 206 to a second end 36, 46, 56, 66,76, 212 and to include at least one passage 38, 48, 58, 68, 78, 208 extending at least partially through the monolithic metallic body 32, 42, 52, 62, 72, 202.

[0026] In an embodiment of the present disclosure, the armature fuel system component 200 includes monolithic metallic body 202 extruded as one piece in a cold extrusion process. Monolithic metallic body 202 extends along a longitudinal axis 222 between first end 206 and opposite second end 212. The monolithic metallic body 202 includes a flange 204 at one of first end 206 and second end 212 and a shaft 210 extending from flange 204 to the other of first end 206 and second end 212. A passage 208 extends along longitudinal axis 222 and opens at first end 206 and second end 212 of monolithic metallic body 202.

[0027] Referring to FIG. 1, a cold extrusion method or process 10 is shown for fabricating a fuel system component, such as one or more of the fuel system components 30, 40, 50, 60, 70 for use in fuel system 101. Process 10 includes a step 14 of forming a monolithic metallic body 32, 42, 52, 62, and / or 72 in the net shape of the desired fuel system component 30, 40, 50, 60, 70 using a cold extrusion process on a billet or blank 12 of metal material.

[0028] As used herein, “net shape” means the extruded monolithic metallic body 32, 42, 52, 62, and / or 72 is output from the cold extrusion process by cold working the material of blank 12 to include the dimensions and surface finish of the corresponding fuel system component 30, 40, 50, 60, and / or 70 without machining or grinding the external or internal surfaces of the extruded monolithic metallic body 32, 42, 52, 62, and / or 72. The extruded monolithic metallic body 32, 42, 52, 62, and / or 72 can be heat treated with a low pressure carburizing process to provide a hardened case on the finished fuel system component 30, 40, 50, 60, 70.

[0029] The monolithic metallic body 32, 42, 52, 62, and / or 72 is formed from cold extruding blank 12 to extend from a first end of monolithic metallic body 32, 42, 52, 62, and / or 72 to an opposite second of the monolithic metallic body 32, 42, 52, 62, and / or 72. The monolithic metallic body 32, 42, 52, 62, and / or 72 also is formed to include at least one passage forming internal surface(s) that extend at least partially through the monolithic metallic body 32, 42, 52, 62, and / or 72 while cold extruding blank 12.

[0030] In an embodiment, blank 12 is a block or cylinder of metal material of sufficient volume to form the corresponding fuel system component 30, 40, 50, 60, 70. In an embodiment, the metal material for blank 12 is steel, such as a stainless steel material with a chromium and nickel alloy mixture. In an embodiment, the material is 18CrNi8, which provides a low cost,fatigue resistant material that is hardenable using low pressure carburizing heat treatment to provide the desired case hardness for a uniform case depth. Other embodiments contemplate other types of metal materials that are capable of being cold extruded to form the fuel system component 30, 40, 50, 60, 70 according to the present disclosure.

[0031] Blank 12 is inserted during operation 14 into a cold extrusion machine 16. In an embodiment, cold extrusion machine 16 includes at least one die 20 and at least one ram 22 for extruding blank 12 into and / or through the die 20. The die 20 and / or ram 22 can be configured to form the desired fuel system components 30, 40, 50, 60, 70 having one or more of the features discussed herein. The extruded blank 12 is output from cold extrusion machine 16 at operation 18 in the net shape of the desired fuel system components 30, 40, 50, 60, and / or 70.

[0032] Referring to FIG. 2, a method 90 for forming fuel system component 30, 40, 50, 60, and / or 70 as a one-piece monolithic body using a cold extrusion process is disclosed, such as by using cold extrusion process 10 discussed above. Method 90 includes an operation 92 to provide a blank or billet of material, such as blank 12 from which to form the desired fuel system component 30, 40, 50, 60, and / or 70. Method 90 further includes an operation 94 to form fuel system components 30, 40, 50, 60, and / or 70 using a cold extrusion process, such as by using cold extrusion machine 16, to extrude the blank 12 into the net shape of the desired fuel system component 30, 40, 50, 60, and / or 70.

[0033] In an embodiment, the monolithic metallic body 32, 42, 52, 62, 72 of the desired fuel system component 30, 40, 50, 60, 70 is extruded longitudinally from a first end to an opposite second end. In an embodiment, monolithic metallic body 32, 42, 52, 62, 72 is extruded to include at least one passage extending entirely or partially through the monolithic metallic body 32, 42, 52, 62, 72. The net shape of the fuel system component 30, 40, 50, 60, 70 is formed by the extruded monolithic metallic body 32, 42, 52, 62, 72 without requiring machining or drilling or the external surfaces of the body 32, 42, 52, 62, 72 or the internal surfaces forming the passage thereof.

[0034] In addition, a low pressure carburizing heat treatment process can be applied to case harden the outer surfaces of the extruded monolithic metallic body 32, 42, 52, 62, 72 without requiring nitriding or further machining of the hardened surfaces. As a result, a uniform case depth is provided on the monolithic metallic body 32, 42, 52, 62, 72 to provide the fuel system component 30, 40, 50, 60, 70 without the formation of a white layer.

[0035] Referring back to FIG. 1, fuel system component 30 is an example of an armature for fuel injector 100, as shown in FIG. 3. Fuel system component 30 includes monolithic metallic body 32 forming the net shape of the armature that extends from first end 34 to opposite second end 36. Monolithic metallic body 32 also includes a passage 38 extending longitudinally through monolithic metallic body 32 that opens at each of the first and second ends 34, 36. In an embodiment, monolithic metallic body 32 includes a flange 32a at first end 34 and a shaft 32b extending from flange 32a to second end 36. An exemplary embodiment of armature fuel system component 30 is discussed herein with respect to armature fuel system component 200.

[0036] Fuel system component 40 is an example of a valve seat, such as for a pilot valve of fuel injector 100. Fuel system component 40 includes monolithic metallic body 42 forming the net shape of the valve seat that extends from first end 44 to opposite second end 46. Monolithic metallic body 42 also includes a passage 48 extending longitudinally through monolithic metallic body 42 that opens at each of the first and second ends 44, 46. In an embodiment, monolithic metallic body 42 includes a cylindrically shaped flange 42a at second end 46 and a smaller in cross-section, cylindrically shaped shaft 42b extending from flange 42a to first end 34. In an embodiment, first end 44 is configured as a valve seat, such as by including a concave shape, against which a ball valve can be engaged.

[0037] Fuel system component 50 is an example of a nozzle, such as for a nozzle for fuel injector 100. Fuel system component includes monolithic metallic body 52 forming the net shape of the nozzle that extends from first end 54 to opposite second end 56. Monolithic metallic body 52 also includes a passage 58 extending longitudinally into monolithic metallic body 52. In an embodiment, monolithic metallic body 52 includes a cylindrically shaped proximal portion 52a at first end 54 that is larger than a cylindrically shaped distal portion 52b at second end 56. In an embodiment, passage 58 is open at first end 54 and is closed at second end 56 by, for example, a convex semi-spherical dome 52d.

[0038] As shown in FIG. 3, in an embodiment the passage 58 is larger in proximal portion 52a than in the distal portion 52b in order to provide the desired fit with the corresponding parts of a needle valve type of fuel system component 70 that is located within and along the length of passage 58. Monolithic metallic body 52 can include an external shoulder 52c between proximal and distal portions 52a, 52b that is engaged by a nozzle retainer type of fuel system component 60. Monolithic metallic body 52 can include an internal lip or shoulder 58c along passage 58 betweenthe differently sized parts of passage 58. After extruding the monolithic metallic body 52, fuel spray holes 136 can be formed through dome 52d at second end 56 to enable injection of fuel from passage 58 during operation of injector 100. The spray holes 136 can be formed via any suitable technique, including by lasers, drilling, and / or be micro-machining, for example.

[0039] Fuel system component 60 is an example of a retainer, such as for retaining nozzle 50 on injector body 102 of fuel injector 100 or for retaining a valve assembly 150, armature fuel system component 30, and / or valve seat fuel system component 40, within body 102 of fuel injector 100. The fuel system component 60 includes monolithic metallic body 62 forming the net shape of the retainer that extends from first end 64 to opposite second end 66. Monolithic metallic body 62 also includes a passage 68 extending longitudinally through monolithic metallic body 62 that opens at first end 64 and at second end 66. In an embodiment, monolithic metallic body 62 includes a cylindrically shaped proximal portion 62a at first end 64 that is larger than a cylindrically shaped distal portion 62b at second end 66.

[0040] As discussed with respect to FIG. 3, the passage 68 is larger in proximal portion 62a than in the distal portion 62b in order to provide the desired fit with the corresponding parts of nozzle 50 or valve assembly 150 positioned therein and to engage injector body 102. Monolithic metallic body 62 can include an external shoulder 62c between proximal and distal portions 62a, 62b. Passage 68 can include an internal lip or shoulder 68a between the differently sized parts of passage 68. After extruding the monolithic metallic body 62, threads can be formed internally or externally at first end 64 and / or at second end 66 for mounting to the nozzle fuel system component 50, injector body 102, or other part or component of fuel injector 100.

[0041] Fuel system component 70 is an example of a needle, such as for a needle valve of fuel injector 100. Fuel system component 70 includes monolithic metallic body 72 forming the net shape of the needle extending from first end 74 to opposite second end 76. Monolithic metallic body 72 also includes proximal guide projections 72a and distal guide projections 72b. Passages 78 extend obliquely through monolithic metallic body 72 at the distal guide projections 72b of monolithic metallic body 72. Distal end 76 includes a needle tip 79 that is configured to engage a valve seat 142 formed in the interior of nozzle fuel system component 50 to selectively stop and start fuel from spraying through the spray holes 136 of nozzle fuel system component 50.

[0042] With reference to FIG. 3, there is illustrated a cross-sectional view of an embodiment of fuel injector 100 in fuel system 101. In an embodiment, fuel injector 100 isconnected to fuel distribution system 103, which may include a common rail, fuel pumps, fuel source(s), and / or other parts associated with a fuel system. Fuel injector 100 may include one or more of fuel system components 30, 40, 50, 60, and 70 that are coupled to or within various parts of fuel injector body 102.

[0043] In an embodiment, fuel system component 30 is an armature fuel system component 30 configured like armature fuel system component 200 discussed further below with reference to FIG. 4-10. Armature fuel system component 30, 200 can be employed in association with valve assembly 150 of fuel injector 100. Fuel injector 100 may include valve seat fuel system component 40 employed in association with valve assembly 150 within fuel injector body 102. Fuel injector 100 may include nozzle fuel system component 50 positioned at a distal end of injector body 102.

[0044] Fuel injector 100 can also include one or more retainer fuel system components 60. For example, one retainer fuel system component 60 can be configured to threadingly engage to the proximal end of injector body 102 for retaining the valve assembly 150 within fuel injector body 102. In another example, another fuel system component retainer 60 can be configured to threadingly engage to a distal end of injector body 102 in retain nozzle fuel system component 50 thereon.

[0045] Fuel injector 100 can also include a needle fuel system component 70. The needle fuel system component 70 is positioned in passage 58 of nozzle fuel system component 50 and in a passage of injector body 102 to function as a needle valve. Fuel injector 100 may also include a needle sleeve 106, and a needle seal 108 housed in injector body 102. A plunger 112 can extend through passage 58 of armature fuel system component 30, 200.

[0046] Armature fuel system component 30, 200 is configured to move up and down relative to injector body 102 and valve seat fuel system component 40 to facilitate opening and closing of valve assembly 150 of fuel injector 100. Stator assembly 122, which includes solenoid 148, may be disposed directly above armature fuel system component 30, 200 so that when solenoid 148 is in an active state, armature fuel system component 30, 200 moves to an upward position. When solenoid 148 is in an inactive state, armature fuel system component 30, 200 moves to a downward position. An air gap may provide a distance between stator assembly 122 and armature fuel system component 30, 200.

[0047] The upper portion of passage 68 of the upper retainer fuel system component 60 at the upper end of injector body 102 receives armature fuel system component 30, 200, plunger 112,an armature spring 1 18, a spring disk 120, and a stator assembly 122. The lower portion of passage 68 of retainer fuel system component 60 receives shaft portion 42b or valve seat fuel system component 40. Injector body 102 receives the upper end portion of needle fuel system component 70, needle sleeve 106, needle seal 108, a valve seat fuel system component 40, and a check ball 126.

[0048] The region of fuel injector 100 along and above passage 68 of the upper retainer fuel system component 60 provides a lower pressure environment of fuel injector 100 relative to a high pressure environment below check ball 126. Stator assembly 122 is fixed within passage 68 and retained in place by upper retainer fuel system component 60. A bottom surface of stator assembly 122 is a precision calibrated distance away from an upper surface of armature fuel system component 30, 200. At the other end of armature fuel system component 30, 200 is a check ball retainer 130 that supports armature fuel system component 30, 200 via abutting engagement.

[0049] A middle section of plunger 112 includes an angled shoulder 113 disposed on the upper surface of armature fuel system component 30, 200 which creates a reciprocal connection such that when armature fuel system component 30, 200 moves in an upward direction, plunger 112 moves therewith. Armature spring 118 is biased against flange 32a, 204 of armature fuel system component 30, 200 and biases armature fuel system component 30, 200 and plunger 112 in an upward direction. Armature fuel system component 30, 200 includes passage 38, 208 that receives a shaft 115 of plunger 112 therethrough. An outer diameter of the shaft 115 is sized and configured to provide a close or match fit in relation to an inner diameter of passage 38, 208 while still permitting sliding movement of plunger 112. This close / match fit inhibits fuel leakage between the outer diameter of the shaft 115 of plunger 112 and the inner diameter of passage 38, 208 while permitting relative sliding movement.

[0050] The lower portion of fuel injector body 102 includes an inner cavity that houses the proximal portion of needle fuel system component 70, needle sleeve 106, needle seal 108, valve seat fuel system component 40, and check ball 126. The inner cavity of fuel injector body 102 also houses a needle spring 134 that biases needle fuel system component 70 in a downward direction and applies a closing spring force to needle fuel system component 70 thereby preventing fuel from exiting through injector orifice(s) 136. Needle seal 108 includes control orifices 138 integrated within needle seal 108 to admit fuel into needle seal 108 while a proximal end of needle fuel system component 70 is positioned within needle seal 108. Needle seal 108 is disposed aboveneedle fuel system component 70 and includes end points that terminate adjacent needle sleeve 106.

[0051] A surface of a lower end of valve seat fuel system component 40 abuts a top surface of needle seal 108, while a surface of an upper end of valve seat fuel system component 40 is disposed immediately below armature spring 118. Valve seat fuel system component 40 further includes valve seat central passage 48 that extends longitudinally from the lower end 46 of valve seat fuel system component 40 toward the upper end 44.

[0052] Needle fuel system component 70 moves up and down longitudinally in the injector body 102 to selectively start and stop fuel injection from the injector body 102. A distal second end 76 of needle fuel system component 70 is located at a distal portion of the nozzle fuel system component 50 which defines a needle valve seat 142 that seats a tip 79 of needle fuel system component 70 in between fuel injection events. For example, during a fuel injection event using fuel system 100, needle fuel system component 70 is lifted off the needle seat 142 so that fuel is injected into an engine cylinder (not shown).

[0053] Injector body 102 further includes fuel entry orifice 144 which is configured to supply fuel to the inner cavity of injector body 102. Cross-drilled fluid passages 78 in needle fuel system component 70 also facilitate fuel flow throughout the inner cavity of injector body 102. Control orifices 138 function to route fuel flow up valve seat passage 48. When coils 121 are deenergized and solenoid 148 is in an inactive state, check ball 126 is in sealing engagement with valve seat fuel system component 40. Check ball 126 also functions as a moveable valve member and thus moves out of sealing engagement with valve seat fuel system component 40. When check ball 126 is in sealing engagement with valve seat fuel system component 40, fuel from nozzle fuel system component 50 and the inner cavity of injector body 102 is blocked from flowing proximally through passage 48. When fuel is supplied to the inner cavity of injector body 102 and check ball 126 is in sealing engagement with valve seat fuel system component 40, the inner cavity of injector body 102 becomes a highly pressurized volume. When check ball 126 functions as a moveable valve member and moves out of sealing engagement with valve seat fuel system component 40, high pressure fuel flows up valve seat central passage 48 through valve seat fuel system component 40 and into passage 68 of the upper retainer fuel system component 60.

[0054] Fuel injector 100 utilizes needle fuel system component 70 in a normally closed position. When needle fuel system component 70 is in a normally closed position, coils 121 arede-energized and solenoid 148 is in an inactive state. Fuel injector 100 also includes a plunger return spring 151 that exerts a spring force downwardly such that plunger 112 and armature fuel system component 30, 200 exert a downward force on check ball retainer 130, which thereby secures and retains check ball 126 into sealing engagement with valve seat fuel system component 40. Pressurized fuel is continuously supplied to the inner cavity of injector body 102.

[0055] When coils 121 are de-energized, fuel from the inner cavity of injector body 102 is blocked from entering passage 68, thus the inner cavity of injector body 102 becomes highly pressurized. Due to the fuel supply pressure acting downwardly on needle fuel system component 70, a large downward hydraulic force pushes needle fuel system component 70 in the downward direction. Needle spring 134 is also positioned in the inner cavity of injector body 102 and is compressed about the upper end 74 of needle fuel system component 70 such that when solenoid 148 is inactive, high pressure fuel as well as a downward spring force on needle fuel system component 70 both act to secure needle fuel system component 70 against needle valve seat 142 formed by monolithic metallic body 52 in passage 58 of nozzle 50. Securing needle fuel system component 70 against needle valve seat 142 prevents high pressure fuel from exiting fuel injector 100 via injector spray holes 136 of nozzle fuel system component 50.

[0056] In an example use of armature fuel system component 30, 200 in fuel injector 100, flange 204 is positioned below solenoid 148 and coils 121. Plunger 112 includes a shaft portion that is disposed in and received by passage 38, 208 of armature fuel system component 30, 200 to create a reciprocal connection such that when armature fuel system component 30, 200 moves in an upward direction, plunger 112 moves therewith. Armature spring 118 may be biased against the flange 32a, 204 to bias armature fuel system component 30, 200 and plunger 112 in the upward direction.

[0057] In an embodiment, armature fuel system component 30, 200 is configured to axially move in fuel injector 100 or other device as part of valve assembly 150 to facilitate opening and closing of the valve assembly 150. In the illustrated embodiment of FIG. 3, stator assembly 122, which includes solenoid 148, may be disposed directly above armature fuel system component 30, 200 so that when solenoid 148 is in an active state, armature fuel system component 30, 200 moves to an upward position. When solenoid 148 is in an inactive state, armature fuel system component 30, 200 moves to a downward position. An air gap, for example, may provide a distance between stator assembly 122 and armature fuel system component 30, 200. Second end 36, 212 of armaturefuel system component 30, 200 may be supported by check ball retainer 130. Armature spring 1 18 may be biased against the flange 32a, 204 to bias armature fuel system component 30, 200 and plunger 112 in the upward direction.

[0058] Referring to FIGs. 4-8, further details of an embodiment of armature fuel system component 200 are shown. Armature fuel system component 200 includes flange 204 that extends radially outwardly from and perpendicular to shaft 210. Flange 204 includes an outer edge 226 forming a circular shape, with flange 204 extending radially outwardly from passage 208, and shaft 210 extending axially from a side of flange 204. In an embodiment, flange 204 is disc-shaped and shaft 210 is cylindrical in shape, and passage 208 extends longitudinally through flange 204 and shaft 210.

[0059] In an embodiment, flange 204 includes an outer diameter defined by outer edge 226 that is, or is about, 1.7 to 2.3 times larger than the largest outer diameter portion defined by the outer surface of shaft 210. In an embodiment, flange 204 includes an outer diameter that is, or is about, 3.5 to 4.0 times larger than the smallest outer diameter portion of shaft 210. In an embodiment, flange 204 includes an outer diameter defined by outer edge 226 that is at last 2 times larger than the largest outer diameter portion defined by the outer surface of shaft 210. In an embodiment, flange 204 includes an outer diameter that is, or is at least 3.5 times larger than the smallest outer diameter portion of shaft 210.

[0060] Flange 204 includes a plurality of slots 228 that extend through flange 204. Each of the plurality of slots 228 extends radially inwardly from outer edge 226 of flange 204 to a terminal end 230 of the corresponding one of the plurality of slots 228. In an embodiment, the plurality of slots 228 is four slots 228 spaced equi-angularly around flange 204.

[0061] In an embodiment, flange 204 includes an end surface at first end 206 of the monolithic metallic body 202 that includes an outer end face portion 244 around passage 208. Flange 204 also defines a recessed end face portion 236 at first end 206 that is spaced radially outwardly from outer end face portion 244. Recessed end face portion 236 is connected to outer end face portion 244 with a concavely curved transition 246. Outer end face portion 244 includes a channel 238 that extends around the opening of passage 208 at first end 206 of monolithic metallic body 202. In an embodiment, flange 204 includes a second face 240 opposite recessed end face portion 236. Second face 240 faces second end 212 and extends radially outwardly from shaft 210.

[0062] In an embodiment, flange 204 includes a first flange portion 232 extending radially outwardly from the shaft 210 having a first thickness tl between recessed end face 236 and second face 240. Flange 204 also includes a second flange portion 234 between adjacent pairs of slots 228. Second flange portion 234 extends radially outwardly from the first flange portion 232 to the outer edge 226 of flange 204. Second flange portion 234 tapers from the first thickness tl to a second, lesser thickness t2 between recessed end face 236 and second face 240 at the outer edge 226 of flange 204. The reduction in mass of flange 204 using slots 228 and / or tapered second flange portion 234 assists in movement of the armature fuel system component 200 during valve opening and closing operations.

[0063] Flange 204 includes a plurality of holes 242 that each extend axially through the recessed end face portion 236 and second face 240. Each of the plurality of holes 242 is located between a corresponding pair of the plurality of slots 228. Holes 242 are cylindrical in the illustrated embodiment, but other shapes for holes 242 are also contemplated.

[0064] In an embodiment, holes 242 are spaced equi -angularly from one another around flange 204 at angle Al. In an embodiment, four holes 242 are provided that are spaced at an angle Al of 90 degrees. Similarly, slots 228 can be spaced at an equi -angularly at the same angle Al but located so that each hole 242 is positioned between a corresponding pair of slots 228. Other embodiments contemplate fewer than four holes 242 and / or slots 228, or more than four holes 242 and / or slots 228.

[0065] In an embodiment, holes 242 are diffusion holes that can influence fluid flow during all points of travel of the armature fuel system component 200. During travel of the armature fuel system component 200 in the direction toward first end 206, fluid on outer end face portion 244 and recessed end face portion 236 compresses and can lead to high pressure spikes. The presence of diffusion holes 242, recess end face portion 236, and / or slots 228 helps in diffusing squeeze film pressure spikes during armature travel and hence can increase a velocity of the armature fuel system component 200.

[0066] During travel of the armature fuel system component 200 in a direction toward second end 212, fluid, such as fuel, flows from second face 240 of flange 204 to the outer end face portion 244 and recessed end face portion 236 via the diffusion holes 242 and thereby can reduce hydraulic drag on the armature fuel system component 200 and increase the velocity.

[0067] In an embodiment, passage 208 includes a first diameter DI adjacent to second end 212 of monolithic metallic body 202 and a second diameter D2 along a majority of a length of passage 208 between the first and second ends 206, 212 of monolithic metallic body 202. First diameter DI of passage 208 is greater than second diameter D2 of passage 208. In an embodiment, a lip 250 connects the transition of diameter DI to diameter D2. In an embodiment, lip 250 is obliquely oriented to longitudinal axis 222 at an angle A2, as shown in FIG. 8.

[0068] In an embodiment, passage 208 includes a transition part 248. Transition part 248 may include a frusto-conical shape that transitions from the second diameter D2 to the opening of passage 208 in outer end face portion 244 at first end 206 of monolithic metallic body 202. In an embodiment, transition part 248 is flared to open wider at outer end face portion 244 and be greater than diameter D2, as indicated by flare angle F in FIG. 7.

[0069] In an embodiment, shaft 210 of monolithic metallic body 202 includes an outer surface 252 extending from flange 204 to second end 212. Outer surface 252 extends from second end 212 of body monolithic metallic 202 to second face 240 of flange 204. In an embodiment, outer surface 252 has a stepped surface profile along a portion of the length of shaft 210 adjacent to flange 204.

[0070] In an embodiment, the stepped surface profile of outer surface 252 of shaft 204 includes a first shaft portion 254 adjacent to flange 204 having a first outer diameter GDI. The stepped surface profile also includes a second shaft portion 256 adjacent to first portion 254. Second shaft portion 256 includes a second outer diameter OD2 that is less than first outer diameter OD1. The stepped outer surface profile of outer surface 252 of shaft 204 includes a third shaft portion 258 adjacent to second shaft portion 256. Third shaft portion 258 extends to second end 212 of monolithic metallic body 202. Third shaft portion 258 has a third outer diameter OD3 that is less than the second outer diameter OD2.

[0071] In an embodiment, a first fillet 260 connects second face 240 to first shaft portion 254, a second fillet 262 connects first shaft portion 254 to second shaft portion 256, and a third fillet 264 connects second shaft portion 256 to third shaft portion 258. In an embodiment, each of the first, second and third fillets 260, 262, 264 includes a concavely curved shape to provide a non- angular transition between shaft portions 254, 256, 258.

[0072] Referring to FIG. 9, a schematic diagram of a cold extrusion process 600 for extruding armature fuel system component 200 is shown. Process 600 includes a billet or blank602 of material. In an embodiment, blank 602 is a block or cylinder of metal material of sufficient volume to form armature fuel system component 200. In an embodiment, the metal material for blank 602 is steel, such as a low carbon steel.

[0073] Other embodiments contemplate other types of metal materials that are capable of being cold extruded to form armature fuel system component 200. In an embodiment, the monolithic metallic body 202 is formed to include the net shape of armature fuel system component 200 by cold extruding a blank of stainless steel material with a chromium and nickel alloy mixture. In one embodiment, the stainless steel material is 18CrNi8.

[0074] Blank 602 is inserted during operation 604 into a cold extrusion machine 606. In an embodiment, cold extrusion machine 606 includes at least one die 610 and at least one ram 612 for extruding blank 602 into and / or through the die 610. The die 610 and / or ram 612 can be configured to form monolithic metallic body 202 of armature fuel system component 200 having one or more of the features discussed above. The extruded blank 602 is output from cold extrusion machine 606 at operation 608 having the net shape of armature fuel system component 200.

[0075] Referring to FIG. 10, a method 700 for forming armature fuel system component 200 as a one-piece monolithic body using a cold extrusion process is disclosed, such as by using cold extrusion process 600 discussed above. Method 700 includes an operation 702 to provide a blank or billet of material, such as blank 602 from which to form the armature fuel system component 200. Method 700 further includes an operation 704 to form armature fuel system component 200 using a cold extrusion process, such as by using cold extrusion machine 606, to extrude the blank 602 into a monolithic metallic body 202 that corresponds to the net shape of armature fuel system component 200.

[0076] In an embodiment, monolithic metallic body 202 is extruded along longitudinal axis 222 from first end 206 to opposite second end 212. In an embodiment, monolithic metallic body 202 is extruded along longitudinal axis 222 from second end 212 to opposite first end 206.

[0077] Various aspects of the present disclosure are contemplated. According to one aspect of the present disclosure, a method of fabricating a fuel system component for use in association with a fuel system includes forming a monolithic metallic body that corresponds to a net shape of the fuel system component using a cold extrusion process. The monolithic metallic body is formed during the cold extrusion process to extend from a first end to a second end and to include at least one passage extending at least partially through the monolithic body.

[0078] In an embodiment, forming the monolithic metallic body includes forming an armature fuel system component or a valve seat fuel system component in which the net shape includes a flange at one of the first end or the second end and a shaft extending from the flange.

[0079] The shaft extends along the longitudinal axis from the flange to the other of the first end or the second end of the monolithic metallic body. The net shape also includes the at least one passage extending along the longitudinal axis. The passage opens at the first and second ends of the monolithic metallic body.

[0080] In an embodiment, forming the monolithic metallic body includes forming a fuel injector nozzle fuel system component in which the net shape includes the at least one passage extending along the longitudinal axis with the at least one passage opening at the first end of the monolithic metallic body and closed at the second end of the monolithic metallic body, The method further includes forming one or more spray holes through the second end of the monolithic metallic body so that the one or more spray holes extend from an exterior of the monolithic metallic body to the at least one passage.

[0081] In an embodiment, forming the monolithic metallic body includes forming a retainer fuel system component in which the net shape includes the at least one passage extending along the longitudinal axis and opening at the first end and at the second of the monolithic metallic body. The at least one passage is configured to receive at least part of one or more additional fuel system components therein.

[0082] In an embodiment, the method includes forming one or more additional fuel system components by cold extruding a blank of metal material into a net shape of the one or more additional fuel system components. The one or more additional fuel system components include at least one of a nozzle, a valve seat, an armature, a retainer, and a needle for a fuel injector.

[0083] In an embodiment, forming the monolithic metallic body includes forming an elongated needle fuel system component for a fuel injector in which the net shape includes the at least one passage extending transversely through the monolithic metallic body.

[0084] In an embodiment, forming the monolithic metallic body includes forming the net shape by cold extruding a blank of stainless steel material with a chromium and nickel alloy mixture. In a further embodiment, the stainless steel material is 18CrNi8.

[0085] In an embodiment, the method includes hardening the monolithic metallic body with a low pressure carburizing heat treatment.

[0086] In an embodiment, forming the monolithic metallic body includes forming the at least one passage in the net shape of the monolithic metallic body without drilling or machining the monolithic metallic body.

[0087] According to another aspect or the present disclosure, an armature for use in association with actuation of a valve is provided. The armature includes a monolithic metallic body that is extruded as one piece in a cold extrusion process. The monolithic metallic body extends along a longitudinal axis between a first end and an opposite second. The monolithic metallic body includes a flange at the first end and a shaft extending from the flange. The shaft extends along the longitudinal axis from the flange to the second end of the monolithic metallic body. In addition, a passage that extends along the longitudinal axis and opens at the first and second ends of the monolithic metallic body.

[0088] In an embodiment, the flange extends radially outwardly from the passage and the shaft extends along the passage.

[0089] In a further embodiment, the passage includes a first diameter adjacent the second end of the monolithic metallic body, and a second diameter along a majority of a length of the passage between the first and second ends of the monolithic metallic body. The first diameter of the passage is greater than the second diameter of the passage.

[0090] In a further embodiment, the central passage includes a transition with frusto- conical shape that extends from the second diameter to the opening of the central passage at the first end of the monolithic metallic body.

[0091] In an embodiment, the shaft of the monolithic metallic body includes an outer surface. The outer surface extends from the second end of the monolithic metallic body to the flange, and the outer surface has a stepped surface profile.

[0092] In a further embodiment, the stepped surface profile of the outer surface of the shaft includes first shaft portion adjacent to the flange, a second shaft portion adjacent to the first shaft portion, and a third shaft portion adjacent the second shaft portion. The first shaft portion has a first outer diameter, and the second shaft portion has a second outer diameter that is less than the first outer diameter. The third shaft portion extends from the second shaft portion to the second end of the monolithic metallic body, and the third shaft portion has a third outer diameter that is less than the second outer diameter.

[0093] In an embodiment, the flange includes a plurality of slots. Each of the plurality of slots extends radially inwardly from an outer edge of the flange to a terminal end of the corresponding one of the plurality of slots.

[0094] In a further embodiment, the flange includes a first flange portion having a first thickness extending radially outwardly from the shaft and a second flange portion extending radially outwardly from the first flange portion to the outer edge of the flange. The second flange portion tapers from the first thickness to a second, lesser thickness at the outer edge of the flange.

[0095] In a further embodiment, the plurality of slots includes four slots located equi- angularly around the flange.

[0096] In a further embodiment, the flange defines an outer end face portion and a recessed end face portion at the second end of the monolithic metallic body. The outer end face portion includes a channel that extends around the opening of the passage at the first end of the monolithic metallic body.

[0097] In a further embodiment, the flange includes a second face opposite the recessed end face portion. The second face extends radially outwardly from the shaft. The flange includes a plurality of holes. Each of the plurality of holes extends axially through the recessed end face portion and the second face.

[0098] In a further embodiment, each of the plurality of holes is located between a corresponding pair of the plurality of slots.

[0099] According to another aspect of the present disclosure, a method of fabricating an armature for use in association with actuation of a valve includes forming a monolithic metallic body using a cold extrusion process. The monolithic metallic body is formed to include a flange at a first end of the monolithic metallic body, a shaft extending from the flange along a longitudinal axis, the shaft extending to a second end of the monolithic metallic body that is opposite the first end, and a passage that extends along the longitudinal axis and opens at the first and second ends of the monolithic metallic body.

[0100] In an embodiment, the passage includes a first diameter adjacent the second end of the monolithic metallic body, and a second diameter along a majority of a length of the central passage between the first and second ends of the monolithic metallic body. The first diameter of the passage is greater than the second diameter of the passage. A transition with a frusto-conicalshape that extends from the second diameter to the opening of the passage at the second end of the monolithic metallic body.

[0101] In an embodiment, the monolithic metallic body is formed during the cold extrusion process to provide the flange with a plurality of slots. Each of the plurality of slots extends radially inwardly from an outer edge of the flange to a terminal end of the corresponding one of the plurality of slots.

[0102] In an embodiment, the monolithic metallic body is formed during the cold extrusion process to provide the flange with a first flange portion having a first thickness extending radially outwardly from the shaft, and a second flange portion extending radially outwardly from the first flange portion to the outer edge of the flange. The second flange portion tapers from the first thickness to a second, lesser thickness at the outer edge of the flange.

[0103] In an embodiment, the monolithic metallic body is formed during the cold extrusion process to provide the flange with an outer end face portion and a recessed end face portion at the first end of the monolithic metallic body. The recessed end face portion extends radially outwardly from the recessed end face portion. The outer end face portion includes a channel that extends around the opening of the passage at the first end of the monolithic metallic body.

[0104] In a further embodiment, the monolithic metallic body is formed during the cold extrusion process to the provide the flange with a second face opposite the recessed end face portion and a plurality of holes. The second face extends radially outwardly from the shaft, and each of the plurality of holes extends axially through the recessed end face portion and the second face.

[0105] In an embodiment, the monolithic metallic body is formed during the cold extrusion process to include an outer surface on the shaft of the monolithic metallic body that extends from the second end of the monolithic metallic body to the flange. The outer surface is formed with a stepped surface profile that includes a first shaft portion adjacent the flange, a second shaft portion adjacent the first shaft portion, and a third shaft portion extending from the second shaft portion to the second end. The first shaft portion has a first outer diameter, the second shaft portion has a second outer diameter less than the first outer diameter, and the third shaft portion has a third outer diameter less than the second outer diameter.

[0106] In a further embodiment, the monolithic metallic body is formed during the cold extrusion process to include a first fillet between the flange and the first shaft portion, a secondfillet between the first shaft portion and the second shaft portion, and a third fillet between the second shaft portion and the first shaft portion.

[0107] While illustrative embodiments of the disclosure have been illustrated and described in detail in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character, it being understood that only certain exemplary embodiments have been shown and described and that all changes and modifications that come within the spirit of the claimed inventions are desired to be protected. It should be understood that while the use of words such as preferable, preferably, preferred or more preferred utilized in the description above indicates that the feature so described may be more desirable, it nonetheless may not be necessary and embodiments lacking the same may be contemplated as within the scope of the invention, the scope being defined by the claims that follow. In reading the claims, it is intended that when words such as “a,” “an,” “at least one,” or “at least one portion” are used there is no intention to limit the claim to only one item unless specifically stated to the contrary in the claim. When the language “at least a portion” and / or “a portion” is used the item can include a portion and / or the entire item unless specifically stated to the contrary.

Claims

WHAT IS CLAIMED IS:

1. A method of fabricating a fuel system component for use in association with a fuel system, the method comprising: forming a monolithic metallic body that corresponds to a net shape of the fuel system component using a cold extrusion process, the monolithic metallic body being formed during the cold extrusion process to extend from a first end to a second end and to include at least one passage extending at least partially through the monolithic body.

2. The method according to claim 1, wherein forming the monolithic metallic body includes forming an armature fuel system component or a valve seat fuel system component in which the net shape includes: a flange at one of the first end or the second end; a shaft extending from the flange, the shaft extending along the longitudinal axis from the flange to the other of the first end or the second end of the monolithic metallic body; and the at least one passage extending along the longitudinal axis, the passage opening at the first and second ends of the monolithic metallic body.

3. The method according to claim 1, wherein forming the monolithic metallic body includes forming a fuel injector nozzle fuel system component in which the net shape includes the at least one passage extending along the longitudinal axis with the at least one passage opening at the first end of the monolithic metallic body and closed at the second end of the monolithic metallic body, and the method comprises: forming one or more spray holes through the second end of the monolithic metallic body so that the one or more spray holes extend from an exterior of the monolithic metallic body to the at least one passage.

4. The method according to claim 1, wherein forming the monolithic metallic body includes forming a retainer fuel system component in which the net shape includes the at least one passage extending along the longitudinal axis and opening at the first end and at the second ofthe monolithic metallic body, wherein the at least one passage is configured to receive at least part of one or more additional fuel system components therein.

5. The method according to claim 4, further comprising forming the one or more additional fuel system components by cold extruding a blank of metal material into a net shape of the one or more additional fuel system components, wherein the one or more additional fuel system components include at least one of a nozzle, a valve seat, an armature, and a needle for a fuel injector.

6. The method according to claim 1, wherein forming the monolithic metallic body includes forming an elongated needle fuel system component for a fuel injector in which the net shape includes the at least one passage extending transversely through the monolithic metallic body.

7. The method according to any of claims 1-6, wherein forming the monolithic metallic body includes forming the net shape by cold extruding a blank of stainless steel material having a chromium and nickel alloy mixture.

8. The method according to claim 7, wherein the stainless steel material is 18CrNi8.

9. The method according to any of claims 1-6, comprising hardening the monolithic metallic body with a low pressure carburizing heat treatment.

10. The method according to any of claims 1-6, wherein forming the monolithic metallic body includes forming the at least one passage in the net shape of monolithic metallic body without drilling or machining the monolithic metallic body.

11. An armature for use in association with actuation of a valve, the armature comprising: a monolithic metallic body being extruded as one piece in a cold extrusion process, the monolithic metallic body extending along a longitudinal axis between a first end and an opposite second, the monolithic metallic body including: a flange at the first end;a shaft extending from the flange, the shaft extending along the longitudinal axis from the flange to the second end of the monolithic metallic body; and a passage that extends along the longitudinal axis and opens at the first and second ends of the monolithic metallic body.

12. The armature according to claim 11, wherein the flange extends radially outwardly from the passage and the shaft extends along the passage.

13. The armature according to claim 12, wherein the passage includes: a first diameter adjacent the second end of the monolithic metallic body; a second diameter along a majority of a length of the passage between the first and second ends of the monolithic metallic body; and the first diameter of the passage is greater than the second diameter of the passage.

14. The armature according to claim 13, wherein the central passage includes a transition with frusto-conical shape that extends from the second diameter to the opening of the central passage at the first end of the monolithic metallic body.

15. The armature according to claim 11, wherein: the shaft of the monolithic metallic body includes an outer surface; the outer surface extends from the second end of the monolithic metallic body to the flange; and the outer surface has a stepped surface profile.

16. The armature according to claim 15, wherein the stepped surface profile of the outer surface of the shaft includes: a first shaft portion adjacent to the flange, the first shaft portion having a first outer diameter; a second shaft portion adjacent to the first shaft portion, the second shaft portion having a second outer diameter, wherein the second outer diameter is less than the first outer diameter; anda third shaft portion adjacent the second shaft portion, the third shaft portion extending from the second shaft portion to the second end of the monolithic metallic body, the third shaft portion having a third outer diameter that is less than the second outer diameter.

17. The armature according to claim 11, wherein the flange includes a plurality of slots, each of the plurality of slots extending radially inwardly from an outer edge of the flange to a terminal end of the corresponding one of the plurality of slots.

18. The armature according to claim 17, wherein the flange includes: a first flange portion having a first thickness extending radially outwardly from the shaft; and a second flange portion extending radially outwardly from the first flange portion to the outer edge of the flange, the second flange portion tapering from the first thickness to a second, lesser thickness at the outer edge of the flange.

19. The armature according to claim 18, wherein the plurality of slots includes four slots located equi-angularly around the flange.

20. The armature according to claim 18, wherein the flange defines an outer end face portion and a recessed end face portion at the second end of the monolithic metallic body, the outer end face portion including a channel that extends around the opening of the passage at the first end of the monolithic metallic body.

21. The armature according to claim 20, wherein: the flange includes a second face opposite the recessed end face portion, and the second face extends radially outwardly from the shaft; and the flange includes a plurality of holes, each of the plurality of holes extending axially through the recessed end face portion and the second face.

22. The armature according to claim 21, wherein each of the plurality of holes is located between a corresponding pair of the plurality of slots.

23. A method of fabricating an armature for use in association with actuation of a valve, the method comprising: forming a monolithic metallic body using a cold extrusion process, the monolithic metallic body formed to include a flange at a first end of the monolithic metallic body, a shaft extending from the flange along a longitudinal axis, the shaft extending to a second end of the monolithic metallic body that is opposite the first end, and a passage that extends along the longitudinal axis and opens at the first and second ends of the monolithic metallic body.

24. The method according to claim 23, wherein forming the monolithic metallic body includes forming the passage by the cold extrusion process to include: a first diameter adjacent the second end of the monolithic metallic body; a second diameter along a majority of a length of the central passage between the first and second ends of the monolithic metallic body; the first diameter of the passage is greater than the second diameter of the passage; and a transition with a frusto-conical shape that extends from the second diameter to the opening of the passage at the second end of the monolithic metallic body.

25. The method according to claim 23, wherein forming the monolithic metallic body includes forming the flange with a plurality of slots during the cold extrusion process so that each of the plurality of slots extending radially inwardly from an outer edge of the flange to a terminal end of the corresponding one of the plurality of slots.

26. The method according to claim 23, wherein forming the monolithic metallic body includes forming the flange of the monolithic metallic body during the cold extrusion process to include: a first flange portion having a first thickness extending radially outwardly from the shaft; and a second flange portion extending radially outwardly from the first flange portion to the outer edge of the flange, the second flange portion tapering from the first thickness to a second, lesser thickness at the outer edge of the flange.

27. The method according to claim 23, wherein forming the monolithic metallic body includes forming the flange of the monolithic metallic body during the cold extrusion process to include: an outer end face portion and a recessed end face portion at the first end of the monolithic metallic body; the recessed end face portion extending radially outwardly from the recessed end face portion; and the outer end face portion including a channel that extends around the opening of the passage at the first end of the monolithic metallic body.

28. The method according to claim 27, wherein forming the monolithic metallic body includes forming the flange of the monolithic metallic body during the cold extrusion process to include: a second face opposite the recessed end face portion, the second face extending radially outwardly from the shaft; and a plurality of holes, each of the plurality of holes extending axially through the recessed end face portion and the second face.

29. The method according to claim 23, wherein forming the monolithic metallic body includes forming an outer surface of the monolithic metallic body during the cold extrusion process to extend from the second end of the monolithic metallic body to the flange, the outer surface being formed with a stepped surface profile that includes: a first shaft portion adjacent the flange, the first shaft portion having a first outer diameter; a second shaft portion adjacent the first shaft portion, the second shaft portion having a second outer diameter less than the first outer diameter; and a third shaft portion extending from the second shaft portion to the second end, the third shaft portion having a third outer diameter less than the second outer diameter.

30. The method according to claim 29, wherein forming the monolithic metallic body includes forming the monolithic metallic body during the cold extrusion process to include: a first fillet between the flange and the first shaft portion; a second fillet between the first shaft portion and the second shaft portion; and a third fillet between the second shaft portion and the first shaft portion.

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