WO2020263216A1 - Ensemble poussoir destiné à être utilisé dans un système de carburant haute pression d'un moteur à combustion interne - Google Patents
Ensemble poussoir destiné à être utilisé dans un système de carburant haute pression d'un moteur à combustion interne Download PDFInfo
- Publication number
- WO2020263216A1 WO2020263216A1 PCT/US2019/038723 US2019038723W WO2020263216A1 WO 2020263216 A1 WO2020263216 A1 WO 2020263216A1 US 2019038723 W US2019038723 W US 2019038723W WO 2020263216 A1 WO2020263216 A1 WO 2020263216A1
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- WO
- WIPO (PCT)
- Prior art keywords
- tappet
- assembly
- bearing
- tappet body
- tappet assembly
- Prior art date
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Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
- F04B1/00—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders
- F04B1/04—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders having cylinders in star- or fan-arrangement
- F04B1/0404—Details or component parts
- F04B1/0426—Arrangements for pressing the pistons against the actuated cam; Arrangements for connecting the pistons to the actuated cam
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
- F02M59/00—Pumps specially adapted for fuel-injection and not provided for in groups F02M39/00 -F02M57/00, e.g. rotary cylinder-block type of pumps
- F02M59/02—Pumps specially adapted for fuel-injection and not provided for in groups F02M39/00 -F02M57/00, e.g. rotary cylinder-block type of pumps of reciprocating-piston or reciprocating-cylinder type
- F02M59/10—Pumps specially adapted for fuel-injection and not provided for in groups F02M39/00 -F02M57/00, e.g. rotary cylinder-block type of pumps of reciprocating-piston or reciprocating-cylinder type characterised by the piston-drive
- F02M59/102—Mechanical drive, e.g. tappets or cams
Definitions
- Conventional internal combustion engines typically include one or more camshafts in rotational communication with a crankshaft supported in a block, one or more intake and exhaust valves driven by the camshafts and supported in a cylinder head, and one or more pistons driven by the crankshaft and supported for reciprocal movement within cylinders of the block.
- the pistons and valves cooperate to regulate the flow and exchange of gases in and out of the cylinders of the block so as to effect a complete thermodynamic cycle in operation.
- a predetermined mixture of air and fuel is compressed by the pistons in the cylinders, is ignited and combusts, which thereby moves the piston within the cylinder to transfer energy to the crankshaft.
- the mixture of air and fuel can be delivered in a number of different ways, depending on the specific configuration of the engine.
- contemporary engine fuel systems typically include a pump adapted to pressurize fuel from a source (e.g., a fuel tank) and to direct pressurized fuel to one or more fuel injectors selectively driven by an electronic controller.
- a source e.g., a fuel tank
- the fuel injectors atomize the pressurized fuel, which promotes a substantially homogenous mixture of fuel and air used to effect combustion in the cylinders of the engine.
- PFI port fuel injection
- the fuel injectors are arranged up-stream of the intake valves of the cylinder head, are typically attached to an intake manifold, and are used to direct atomized fuel toward the intake valves which mixes with air traveling through the intake manifold and is subsequently drawn into the cylinders.
- a relatively low fuel pressure of 4 bar approximately 58 psi
- the pump of a PFI gasoline fuel system is typically driven with an electric motor.
- DFI direct fuel injection
- modem gasoline DFI fuel systems operate at relatively high fuel pressures, for example 500 bar or higher (approximately 7300 psi). Because the pressure demand of DFI fuel systems is relatively high, a high-pressure fuel pump assembly which is mechanically driven by a rotational movement of a prime mover of the engine (e.g., one of the camshafts) is typically employed.
- the same camshaft used to regulate valves in the cylinder head is also used to drive the high-pressure fuel pump assembly in DFI fuel systems.
- one of the camshafts typically includes an additional lobe that cooperates with a tappet supported in a housing to translate rotational movement of the camshaft lobe into linear movement of the high-pressure fuel pump assembly.
- the high-pressure fuel pump assembly is typically removably attached to the housing with fasteners.
- the housing of the high-pressure fuel pump assembly may be formed as a discrete component, or may be realized as a part of the cylinder head, and includes a tappet cylinder in which the tappet is supported for reciprocating movement.
- the tappet typically includes a bearing which engages the lobe of the camshaft, and a body which supports the bearing and is disposed in force-translating relationship with the high- pressure fuel pump assembly.
- the high-pressure fuel pump assembly typically includes a spring-loaded piston which is pre-loaded against the tappet body when the high-pressure fuel pump assembly is attached to the housing.
- each of the components of an internal combustion engine high-pressure fuel system of the type described above must cooperate to effectively translate movement from the lobe of the camshaft so as to operate the high-pressure fuel pump assembly at a variety of engine rotational speeds and operating temperatures and, at the same time, maintain correct tolerances so as to ensure proper performance.
- each of the components must be designed not only to facilitate improved performance and efficiency, but also so as to reduce the cost and complexity of manufacturing and assembling the fuel system, as well as reduce wear in operation.
- the present invention overcomes the disadvantages in the related art in a tappet assembly for use in translating force between a camshaft lobe and a fuel pump assembly via reciprocal movement within a tappet cylinder having a guide slot.
- the tappet assembly includes a follower assembly having a shaft and first and second bearings rotatably supported by the shaft for engaging the camshaft lobe.
- the tappet assembly further includes an intermediate element disposed between the first and second bearings and coupled to the follower assembly.
- the intermediate element includes a platform for engaging the high-pressure fuel pump assembly.
- the tappet assembly further includes a tappet body with the intermediate element and the follower assembly each disposed therein.
- the tappet assembly of the present invention significantly reduces the complexity of manufacturing high-pressure fuel systems. Moreover, the present invention reduces the cost of manufacturing high-pressure fuel systems that have superior operational characteristics, such as improved engine performance, control, and efficiency, as well as reduced vibration, noise generation, engine wear, emissions, and packaging size.
- Figure l is a perspective view of a high-pressure fuel system, shown depicting portions of a fuel pump assembly, a camshaft lobe, and a housing.
- Figure 2 is a top-side plan view of portions of the high-pressure fuel system of Figure 1, shown without the fuel pump assembly and shown depicting a tappet assembly according to a first embodiment of the present invention supported within a tappet cylinder of the housing.
- Figure 3 is a section view taken along line 3-3 in Figure 2, shown depicting portions of the housing, the tappet assembly, and the camshaft lobe.
- Figure 4 is a section view taken along line 4-4 in Figure 2, shown depicting portions of the housing, the tappet assembly, and the camshaft lobe.
- Figure 5 is an exploded perspective view of the high-pressure fuel system of Figure 1, shown with the camshaft lobe, the fuel pump assembly, and the first embodiment of the tappet assembly of Figures 2-4 spaced from the housing.
- Figure 6 is a perspective view of the first embodiment of the tappet assembly of Figures 2-5.
- Figure 7 is an enlarged partial perspective view of the first embodiment of the tappet assembly of Figures 2-5, shown having a follower assembly supported within a tappet body, the tappet body shown depicted in phantom.
- Figure 8 is a partially-exploded perspective view of the first embodiment of the tappet assembly of Figures 2-6.
- Figure 9 is an exploded perspective view of a second embodiment of a tappet assembly according to the present invention.
- Figure 10 is a partially-exploded perspective view of a third embodiment of a tappet assembly according to the present invention.
- Figure 11 is an exploded perspective view of a fourth embodiment of a tappet assembly according to the present invention.
- Figure 12 is a partially-exploded perspective view of a fifth embodiment of a tappet assembly according to the present invention.
- Figure 13 is a perspective view of a sixth embodiment of a tappet assembly according to the present invention.
- Figure 14 is a perspective view of a seventh embodiment of a tappet assembly according to the present invention.
- Figure 15 is a perspective view of an eighth embodiment of a tappet assembly according to the present invention.
- Figure 16 is a bottom-side plan view of the eighth embodiment of the tappet assembly of Figure 15.
- Figure 17 is a section view taken along line 17-17 in Figure 16.
- Figure 18 is an exploded perspective view of a ninth embodiment of a tappet assembly according to the present invention.
- Figure 19 is a perspective view of a tenth embodiment of the tappet assembly according to the present invention, the tappet body shown depicted in phantom.
- Figure 20 is a section view of the tappet assembly shown in Figure 19.
- Figure 21 is a partially-exploded perspective view of the tappet assembly of Figures 19 and 20.
- the high-pressure fuel system 100 includes a camshaft lobe 102, a high-pressure fuel pump assembly 104, a housing 106, and a tappet assembly 108. Each of these components will be described in greater detail below.
- the camshaft lobe 102 is typically integrated with a camshaft 110 rotatably supported in a cylinder head or engine block of an internal combustion engine (not shown, but generally known in the related art). As is best shown in Figure 3, the illustrated camshaft lobe 102 has a generally rounded eccentric profile and is used to drive the high-pressure fuel pump assembly 104, as described in greater detail below.
- four camshaft lobes 102 are arranged in a rounded- rectangular pattern within the housing 106 and rotate within a housing chamber 112 defined by the housing 106.
- camshaft 110 For the purposes of clarity and consistency, only portions of the camshaft 110, the housing 106, and the housing chamber 112 that are disposed adjacent the camshaft lobe 102 are illustrated herein. Thus, it will be appreciated that the camshaft 110, housing 106, and/or the housing chamber 112 could be configured or arranged in a number of different ways sufficient to cooperate with the high-pressure fuel pump assembly 104 without departing from the scope of the present invention. Specifically, the camshaft 110 and camshaft lobe 102 illustrated herein may be integrated with or otherwise form a part of a conventional engine valvetrain system configured to regulate the flow of gases into and out of the engine (not shown, but generally known in the related art).
- camshaft 110 and/or the camshaft lobe 102 could be configured, disposed, or supported in any suitable way sufficient to operate the high-pressure fuel pump assembly 104 without departing from the scope of the present invention.
- camshaft lobe 102 described herein receives rotational torque directly from the engine, those having ordinary skill in the art will appreciate that the camshaft lobe 102 could be disposed in rotational communication with any suitable prime mover sufficient to operate the high-pressure fuel pump assembly 104 without departing from the scope of the present invention.
- housing 106 and housing chamber 112 adjacent to the camshaft lobe 102 are illustrated throughout the drawings.
- the housing 106 includes a flange 114, which is adapted to releasably secure the high-pressure fuel pump assembly 104, such as with bolts or other fasteners (not shown, but generally known in the related art).
- the housing 106 also includes a tappet cylinder 116, which extends between the housing chamber 112 and the flange 114.
- the tappet assembly 108 is supported for reciprocal movement along the tappet cylinder 116 of the housing 106, as described in greater detail below.
- the tappet cylinder 116 also includes a guide slot 118, which extends between the flange 114 and the housing chamber 112 for indexing the angular position of the tappet assembly 108 with respect to the camshaft lobe 102 (see Figures 2, 3, and 5).
- the guide slot 118 extends to a guide slot end 120 disposed adjacent to and spaced from the housing chamber 112. It will be appreciated that the guide slot end 120 helps prevent the tappet assembly 108 from inadvertently falling into the housing chamber 112 in the absence of the camshaft 110 (e.g., during engine assembly and/or disassembly).
- the high-pressure fuel pump assembly 104 includes a spring- loaded piston, generally indicated at 122, which is pre-loaded against the tappet assembly 108 when the high-pressure fuel pump assembly 104 is attached to the flange 1 14 of the housing 106.
- the high-pressure fuel pump assembly 104 includes a low-pressure port 124 A and a high-pressure port 124B.
- the low-pressure port 124A is typically disposed in fluid communication with a source of fuel such as a fuel tank or a conventional low-pressure fuel system (not shown, but generally known in the related art).
- the high-pressure port 124B is typically disposed in fluid communication with a fuel injector used to facilitate admission of fuel into the engine (not shown, but generally known in the related art).
- the high-pressure fuel pump assembly 104 could be configured in any suitable way, with any suitable number of ports, components, and the like, without departing from the scope of the present invention.
- Rotational movement of the camshaft lobe 102 effects reciprocal movement the tappet assembly 108 along the tappet cylinder 116 of the housing 106 which, in turn, translates force to the spring-loaded piston 122 of the high-pressure fuel pump assembly 104 so as to pressurize fuel across the ports 124 A, 124B.
- potential energy stored in the spring-loaded piston 122 of the high-pressure fuel pump assembly 104 urges the tappet assembly 108 back down the tappet cylinder 116 so as to ensure proper engagement between the tappet assembly 108 and the camshaft lobe 102, as described in greater detail below.
- the tappet assembly 108 generally includes a follower assembly 126, an intermediate element 128, and a tappet body 130, each of which will be described in greater detail below.
- the tappet body 130 of the tappet assembly 108 has a generally cylindrical shape and defines an outer surface 132 and an inner surface 134, each of which have a generally annular profile.
- Two indented walls 136 are formed on the tappet body 130 and are diametrically opposed from each other.
- An aperture 138 is formed in each indented wall 136 extending from the outer surface 132 to the inner surface 134 (see also Figure 4).
- the apertures 138 each have a substantially circular profile, are aligned with each other about an aperture axis A1 (see Figure 8), and cooperate to support the follower assembly 126, as described in greater detail below.
- the tappet body 130 of the tappet assembly 108 also comprises at least one seat 140A, 140B that cooperates with the intermediate member as will be described in greater detail below.
- the tappet assembly includes a first seat 140A and a second seat 140B, each of which is likewise formed extending from the outer surface 132 to the inner surface 134 (see also Figure 3).
- the first and second seats 140A, 140B are also diametrically opposed from each other, and are aligned about a seat axis A2 (see Figure 8).
- the seat axis A2 is arranged perpendicular to and spaced from the aperture axis Al.
- the first and second seats 140A, 140B each have a generally rectangular profile that is configured to support the intermediate element 128, as described in greater detail below.
- the tappet body 130 is formed as a unitary, one-piece component, manufactured from materials such as steel.
- the tappet body 130 is manufactured by a drawing process.
- the apertures 138 and the first and second seats 140 A, 140B may be formed in the tappet body 130 during the drawing process used to form the tappet body 130.
- other machining methods such as drilling and electrical discharge machining (EDM) may also be used.
- EDM electrical discharge machining
- the follower assembly 126 of the tappet assembly 108 includes a shaft 142 and first and second bearings, generally indicated at 144 A and 144B, respectively.
- the first and second bearings 144 A, 144B are each supported for rotation on the shaft 142.
- the first and second bearings 144 A, 144B are realized as roller bearing assemblies.
- other configurations of the first and second bearings 144A, 144B are contemplated by the present disclosure (e.g., hydrodynamic journal bearings).
- the first and second bearings 144A, 144B each extend beneath the bottom of the tappet body 130 so as to engage the camshaft lobe 102 and follow the profile of the camshaft lobe 102 as the camshaft 110 rotates in operation (see Figures 3-4).
- rotation of the camshaft 110 is translated into reciprocal movement of the tappet assembly 108 within the tappet cylinder 116 as the first and second bearings 144A, 144B of the follower assembly 126 roll along the profile of the camshaft lobe 102.
- the follower assembly 126 is coupled to the intermediate element 128 which, in turn, is supported by the tappet body 130 and is interposed between the first bearing 144A and the second bearing 144B along the shaft 142.
- the follower assembly 126, the intermediate element 128, and/or the tappet body 130 can be configured in a number of different ways, such as to accommodate different application requirements of correspondingly-different high-pressure fuel systems 100, without departing from the scope of the present invention.
- the first and second bearings 144 A, 144B of the follower assembly 126 each include an outer race 146, which is adapted to engage the camshaft lobe 102, and a plurality of rollers 148 arranged between the outer race 146 and the shaft 142 (see Figures 4 and 7-8).
- the rollers 148 reduce friction and help distribute load between the shaft 142 and the first and second bearings 144A, 144B during operation.
- the outer race 146 comprises an outer portion 1460 that is adapted to at least partially engage the camshaft lobe 102, and an inner portion 1461 that is adapted to engage the rollers 148.
- each of the first and second bearings 144A, 144B may have a chamfered edge 150 to provide clearance for the bearings 144A, 144B between the inner surface 134 of the tappet body 130 adjacent the respective apertures 138 and indented walls 136.
- the chamfered edges 150 of the bearings 144A, 144B face away from each other in the illustrated embodiment such that the bearings 144 A, 144B have a generally asymmetric profile.
- the chamfered edge 150 is formed on one side of the outer portion 148 of the outer race 146 of each of the bearings 144 A, 144B (a smaller chamfer may be provided on the other side of the outer portion 148 in some embodiments; not shown in detail).
- This configuration allows the width of the outer portion 1460 to maximize contact with the camshaft lobe 102 while still facilitating packaging of the follower assembly 126 within the tappet body 130 and, at the same time, allows both the width of the inner portion 1461 and the length of the rollers 148 to be maximized so as to distribute load across a maximized length of the shaft 142 while generally reducing the rotating mass of the bearings 144 A, 144B.
- the intermediate element 128 of the follower assembly 126 includes a central portion 152, a platform 154, and first and second protrusions 156A, 156B.
- the platform 154 is formed on the central portion 152 of the intermediate element 128 and provides a contact surface that is arranged to engage the spring-loaded piston 122 of the high-pressure fuel pump assembly 104 in force translating relationship (see Figure 5; engagement not shown).
- Each of the first protrusion 156A and the second protrusion 156B extends from the central portion 152 and generally away from the platform 154 in opposing directions.
- a bore 158 is further formed in the central portion 152 and is configured to receive the shaft 142 of the follower assembly 126.
- the platform 154 is disposed slightly above the protrusions 156A, 156B and spaced from the bore 158 such that the platform 154 is spaced from the bearings 144A, 144B and extends outwardly toward the tappet body 130 allowing the contact surface between the spring-loaded piston 122 of the high-pressure fuel pump assembly 104 to be enlarged.
- Each of the protrusions 156A, 156B of the intermediate element 128 has a generally rectangular profile and is configured to be accommodated or otherwise received by one of the respective first and second seats 140A, 140B of the tappet body 130 (see Figure 4).
- the intermediate element 128 further comprises a guide tip 160 extending from at least one of the protrusions 156A, 156B through the respective first or second seat 140 A, 140B and protruding from the tappet body 130.
- the guide tip 160 protrudes beyond the outer surface 132 of the tappet body 130 to be received in and travel along the guide slot 118 of the housing 106 (see Figure 3).
- the first protrusion 156A includes the guide tip 160, which extends through the first seat 140A further away from the central portion 152 and protrudes from the tappet body 130.
- the central portion 152 of the intermediate element 128 is interposed axially between the first and second bearings 144A, 144B.
- the bore 158 of the intermediate element 128 is aligned with the apertures 138 of the tappet body 130 and with the shaft 142.
- the shaft 142 extends through the apertures 138, the first and second bearings 144A, 144B, and the bore 158 of the intermediate element 128.
- the shaft 142 may be retained relative to the tappet body 130 by upsetting opposing ends of the shaft 142 to a diameter larger than the apertures 138.
- Each end may be upset by staking, flaring, or otherwise effectively enlarging opposing ends of the shaft 142 to a size larger than the apertures 138.
- the shaft 142 is retained axially in the tappet body 130 but able to rotate within the apertures 138 and the intermediate element 128.
- the shaft 142 may be fixed against rotation relative to the intermediate element 128 and/or the tappet body 130.
- the indented walls 136 provide clearance between the enlarged opposing ends of the shaft 142 and the tappet cylinder 116.
- the shaft 142 could be configured in any suitable way sufficient to be retained and engage the intermediate element 128, as noted above, without departing from the scope of the present invention.
- the intermediate element 128 of the follower assembly 126 is formed as a unitary, one-piece component. More specifically, in the first embodiment of the tappet assembly 108 illustrated in Figures 2-8, the intermediate element 128 is manufactured from a single piece of sheet steel that has been stamped and contoured to shape. In some embodiments, the platform 154 of the intermediate element 128 may be formed with a coining operation to widen the contact surface that is arranged to engage against the spring-loaded piston 122 of the high-pressure fuel pump assembly 104. However, as will be appreciated from the subsequent description of the embodiment illustrated in Figure 18 below, other manufacturing processes, such as cold-forming, could be utilized. Furthermore, it is contemplated that still other manufacturing processes may be utilized for certain applications, such as casting, forging, metal injection molding, powdered metal sintering, and the like.
- the spring-loaded piston 122 engages against the platform 154 of the intermediate element 128 with the follower assembly 126 engaging the camshaft lobe 102.
- the camshaft lobe 102 urges the follower assembly 126 toward the high-pressure fuel pump assembly 104, where forces are transferred from each of the first and second bearings 144 A, 144B to the shaft 142, through the intermediate element 128, and to the spring-loaded piston 122 of the high-pressure fuel pump assembly 104.
- engagement between the protrusions 156A, 156B and the seats 140 A, 140B effects concurrent movement of the intermediate element 128 and the tappet body 130 as the tappet assembly 108 reciprocates within the tappet cylinder 116.
- FIG. 9 a second embodiment of the tappet assembly of the present invention is shown in Figure 9.
- the second embodiment is similar to the first embodiment of the tappet assembly 108 described above in connection with Figures 2-8.
- the components and structural features of the second embodiment of the tappet assembly that are the same as or that otherwise correspond to the first embodiment of the tappet assembly 108 are provided with the same reference numerals increased by 100. While the specific differences between these embodiments will be described in detail, for the purposes of clarity and consistency, only certain structural features and components common between these embodiments will be discussed and depicted in the drawing(s) of the second embodiment of the tappet assembly 208.
- the above description of the first embodiment of the tappet assembly 108 may be incorporated by reference with respect to the second embodiment of the tappet assembly 208 without limitation.
- the bearings 244A, 244B of the follower assembly 226 are realized as hydrodynamic journal bearings that are rotatably supported via the shaft 242.
- each of the first and second bearings 244A, 244B employs the chamfered edge 250 to provide clearance for the bearings 244A, 244B between the inner surface 234 of the tappet body 230 adjacent the respective indented walls 236.
- the inner portion 2461 is disposed in engagement (e.g., via hydrodynamic“contact”) with the shaft 242 and is wider than the outer portion 2460.
- This likewise allows the width of the outer portion 2460 to maximize contact with the camshaft lobe 102 while still facilitating packaging of the follower assembly 226 within the tappet body 230 and, at the same time, allows the width of the inner portion 2461 to be maximized so as to distribute load across a maximized length of the shaft 242 while generally reducing the rotating mass of the bearings 244 A, 244B.
- FIG. 10 a third embodiment of the tappet assembly of the present invention is shown in Figure 10.
- the third embodiment is similar to the first embodiment of the tappet assembly 108 described above in connection with Figures 2-8.
- the components and structural features of the third embodiment of the tappet assembly that are the same as or that otherwise correspond to the first embodiment of the tappet assembly 108 are provided with the same reference numerals increased by 200. While the specific differences between these embodiments will be described in detail, for the purposes of clarity and consistency, only certain structural features and components common between these embodiments will be discussed and depicted in the drawing(s) of the third embodiment of the tappet assembly 308.
- the above description of the first embodiment of the tappet assembly 108 may be incorporated by reference with respect to the third embodiment of the tappet assembly 308 without limitation.
- the tappet body 330 has an outer surface 332 and an inner surface 334, each having a generally cylindrical profile.
- indented walls 336 are formed on the tappet body 330 arranged diametrically opposed from each other.
- slots 362 are formed in the tappet body 330 adjacent to longitudinal edges of the indented walls 336. The slots 362 facilitate positioning the inner surface 334 of the indented walls 336 in a way that affords additional clearance for the bearings 344A, 344B of the follower assembly 326.
- the bearings 344A, 344B are likewise realized as roller bearings but are provided with a substantially more symmetric profile without distinct chamfered edges that face away from each other (compare Figure 10 with Figure 8).
- the configuration afforded by the third embodiment of the tappet assembly 308 may be advantageously implemented in applications where the camshaft lobe 102 is relatively wide and/or where additional engagement between the bearings 344A, 344B and the camshaft lobe 102 is desirable (e.g., to reduce contact stress during operation).
- FIG. 11 a fourth embodiment of the tappet assembly of the present invention is shown in Figure 11.
- the fourth embodiment is similar to the first embodiment of the tappet assembly 108 described above in connection with Figures 2-8.
- the components and structural features of the fourth embodiment of the tappet assembly that are the same as or that otherwise correspond to the first embodiment of the tappet assembly 108 are provided with the same reference numerals increased by 300. While the specific differences between these embodiments will be described in detail, for the purposes of clarity and consistency, only certain structural features and components common between these embodiments will be discussed and depicted in the drawing(s) of the fourth embodiment of the tappet assembly 408.
- the above description of the first embodiment of the tappet assembly 108 may be incorporated by reference with respect to the fourth embodiment of the tappet assembly 408 without limitation.
- the fourth embodiment of the tappet assembly 408 is shown.
- the fourth embodiment of the tappet assembly 408 is also similar, in certain aspects, to the second embodiment of the tappet assembly 208 described above in connection with Figure 9, and to the third embodiment of the tappet assembly 308 described above in connection with Figure 10.
- the fourth embodiment of the tappet assembly 408 like the second embodiment of the tappet assembly 208, employs bearings 444 A, 444B, which have a journal bearing configuration. Accordingly, the description of this aspect above in connection with the second embodiment may be incorporated by reference with respect to the fourth embodiment of the tappet assembly 408.
- the fourth embodiment of the tappet assembly 408 like the third embodiment of the tappet assembly 308, employs slots 462 formed in the tappet body 430 adjacent to longitudinal edges of the indented walls 436, and bearings 444 A, 444B, which have a substantially symmetric profile without distinct chamfered edges that face away from each other. Accordingly, the above description of these aspects in connection with the third embodiment may be incorporated by reference with respect to the fourth embodiment of the tappet assembly 408.
- FIG. 12 a fifth embodiment of the tappet assembly of the present invention is shown in Figure 12.
- the fifth embodiment is similar to the first embodiment of the tappet assembly 108 described above in connection with Figures 2-8.
- the components and structural features of the fifth embodiment of the tappet assembly that are the same as or that otherwise correspond to the first embodiment of the tappet assembly 108 are provided with the same reference numerals increased by 400. While the specific differences between these embodiments will be described in detail, for the purposes of clarity and consistency, only certain structural features and components common between these embodiments will be discussed and depicted in the drawing(s) of the fifth embodiment of the tappet assembly 508.
- the above description of the first embodiment of the tappet assembly 108 may be incorporated by reference with respect to the fifth embodiment of the tappet assembly 508 without limitation.
- a longitudinal split 564 is formed in the tappet body 530, arranged extending through one of the seats 540A, 540B.
- the tappet body 530 may be manufactured via a stamping operation, such as where stamped sheet steel is rolled to form a generally annular profile with a longitudinal split 564 that defines first and second edges 566A, 566B, which face each other across the longitudinal split 564.
- the longitudinal split 564 is arranged in the tappet body 530 approximately perpendicular to the indented walls 536 and the apertures 538. This arrangement causes the longitudinal split 564 to bisect the first seat 540A.
- each the edges 566A, 566B may be coupled to each other using various techniques known in the art, such as brazing, soldering, welding, and the like.
- the tappet body 530 may be formed resiliently so as to allow relative movement between the first and second edges 566A, 566B.
- the tappet body 530 could be formed such that its profile is larger than the diameter of the tappet cylinder 116.
- the tappet body 530 When installed in the tappet cylinder 116, the tappet body 530 could at least partially compress to bring the first and second edges 566A, 566B closer toward each other, and one or more portions of the tappet body 530 could thus engage against and apply force to the tappet cylinder 116.
- the tappet body 530 could be configured in ways other than with the illustrated longitudinal split 564 where the first and second edges 566 A, 566B are spaced from and movable relative to each other.
- an interlocking split could be utilized in some embodiments, such as various arrangements of vertical, horizontal, curved, and/or angled splits that extend in communication between each other (not shown), where one or more edges define a tab and a slot that are configured to interlock with each other to promote rigidity.
- Other configurations are contemplated.
- FIG. 13 a sixth embodiment of the tappet assembly of the present invention is shown in Figure 13.
- the sixth embodiment is similar to the first embodiment of the tappet assembly 108 described above in connection with Figures 2-8.
- the components and structural features of the sixth embodiment of the tappet assembly that are the same as or that otherwise correspond to the first embodiment of the tappet assembly 108 are provided with the same reference numerals increased by 500. While the specific differences between these embodiments will be described in detail, for the purposes of clarity and consistency, only certain structural features and components common between these embodiments will be discussed and depicted in the drawing(s) of the sixth embodiment of the tappet assembly 608.
- the above description of the first embodiment of the tappet assembly 108 may be incorporated by reference with respect to the sixth embodiment of the tappet assembly 608 without limitation.
- the sixth embodiment of the tappet assembly 608 is shown.
- the sixth embodiment of the tappet assembly 608 is also similar, in certain aspects, to the fifth embodiment of the tappet assembly 508 described above in connection with Figure 12.
- the sixth embodiment of the tappet assembly 608, like the fifth embodiment of the tappet assembly 508, is provided with a longitudinal split 664 formed in the tappet body 630. Accordingly, the description of this aspect above in connection with the fifth embodiment may be incorporated by reference with respect to the sixth embodiment of the tappet assembly 608.
- the tappet body 630 is provided with a plurality of pads, generally indicated at 668, which are formed in the tappet body 630 to help optimize contact with the tappet cylinder 116.
- the pads 668 are arranged about the tappet body 630 and protrude from the outer surface 632 of the tappet body 630 and provide a contact area for contacting the tappet cylinder 116. The reduced size of the contact area reduces wear to the tappet body 630.
- the pads 668 are arranged in four pairs, for a total of eight pads 668, one of each pair being spaced longitudinally along the tappet body 630.
- the tappet body 630 may be formed such that the areas of the outer surface 632 between the pads 668 have no (or only minimal) contact with the tappet cylinder 116.
- the pads 668 may be generally square-shaped with a curved arc-shaped and generally cylindrical profile that corresponds to the shape of the tappet cylinder 116, and may be formed such as via a coining process. Other configurations are contemplated.
- a seventh embodiment of the tappet assembly of the present invention is shown in Figure 14.
- the seventh embodiment is similar to the first embodiment of the tappet assembly 108 described above in connection with Figures 2-8.
- the components and structural features of the seventh embodiment of the tappet assembly that are the same as or that otherwise correspond to the first embodiment of the tappet assembly 108 are provided with the same reference numerals increased by 600. While the specific differences between these embodiments will be described in detail, for the purposes of clarity and consistency, only certain structural features and components common between these embodiments will be discussed and depicted in the drawing(s) of the seventh embodiment of the tappet assembly 708.
- the above description of the first embodiment of the tappet assembly 108 may be incorporated by reference with respect to the seventh embodiment of the tappet assembly 708 without limitation.
- the seventh embodiment of the tappet assembly 708 is shown.
- the seventh embodiment of the tappet assembly 708 is also similar, in certain aspects, to the sixth embodiment of the tappet assembly 608 described above in connection with Figure 13.
- the seventh embodiment of the tappet assembly 708, like the sixth embodiment of the tappet assembly 608, is provided with a plurality of pads 768 radially arranged about the outer surface 732 of the tappet body 730, which is likewise formed with a longitudinal split 764. Accordingly, the description of this aspect above in connection with the sixth embodiment may be incorporated by reference with respect to the seventh embodiment of the tappet assembly 708.
- the tappet body 730 is provided with a plurality of pads, generally indicated at 768, which are arranged about the outer surface 732.
- a total of four pads 768 are formed in the tappet body 730 to help optimize contact with the tappet cylinder 116 during use.
- the pads 768 are generally elongated rectangular-shaped with a curved arc-shaped and generally cylindrical profile that corresponds to the shape of the tappet cylinder 116.
- other configurations, arrangements, profiles, and/or shapes of pads 768 may be employed in certain embodiments.
- an eighth embodiment of the tappet assembly of the present invention is shown in Figures 15-17.
- the eighth embodiment is similar to the first embodiment of the tappet assembly 108 described above in connection with Figures 2-8.
- the components and structural features of the eighth embodiment of the tappet assembly that are the same as or that otherwise correspond to the first embodiment of the tappet assembly 108 are provided with the same reference numerals increased by 700. While the specific differences between these embodiments will be described in detail, for the purposes of clarity and consistency, only certain structural features and components common between these embodiments will be discussed and depicted in the drawing(s) of the eighth embodiment of the tappet assembly 808.
- the above description of the first embodiment of the tappet assembly 108 may be incorporated by reference with respect to the eighth embodiment of the tappet assembly 808 without limitation.
- the eighth embodiment of the tappet assembly 808 is shown.
- the eighth embodiment of the tappet assembly 808 is also similar, in certain aspects, to the seventh embodiment of the tappet assembly 708 described above in connection with Figure 14.
- the eighth embodiment of the tappet assembly 808, like the seventh embodiment of the tappet assembly 708, is provided with a plurality of pads 868 radially arranged about the outer surface 832 of the tappet body 830, which is likewise formed with a longitudinal split 864. Accordingly, the description of this aspect above in connection with the seventh embodiment may be incorporated by reference with respect to the eighth embodiment of the tappet assembly 808.
- the eighth embodiment of the tappet assembly 808 is provided with one or more tabs, generally indicated at 870A, 870B, formed in the tappet body 830 adjacent to each of the seats 840A, 840B. More specifically, and as is best shown in Figures 16-17, a single tab 870A is formed adjacent to the first seat 840 A, and a pair of smaller tabs 870B are formed adjacent to the second seat 840B.
- the tabs 870A, 870B are“bent” or otherwise formed extending inwardly, and are shaped and arranged to abut portions of the protrusions 856A, 856B and/or the guide tip 860 of the intermediate element 828 of the follower assembly 826.
- the tabs 870A, 870B also afford rigidity to the tappet body 830 and help to distribute applied load during use. It will be appreciated that the tabs 870A, 870B may be shaped and/or arranged in ways other than as is illustrated in Figures 15-17 without departing from the scope of the present invention.
- FIG. 18 a ninth embodiment of the tappet assembly of the present invention is shown in Figure 18.
- the ninth embodiment is similar to the first embodiment of the tappet assembly 108 described above in connection with Figures 2-8.
- the components and structural features of the ninth embodiment of the tappet assembly that are the same as or that otherwise correspond to the first embodiment of the tappet assembly 108 are provided with the same reference numerals increased by 800. While the specific differences between these embodiments will be described in detail, for the purposes of clarity and consistency, only certain structural features and components common between these embodiments will be discussed and depicted in the drawing(s) of the ninth embodiment of the tappet assembly 908.
- the above description of the first embodiment of the tappet assembly 108 may be incorporated by reference with respect to the ninth embodiment of the tappet assembly 908 without limitation.
- the intermediate element 928 of the follower assembly 926 comprises a central portion 952 that defines pockets 972 for accommodating the bearings 944A, 944B.
- the intermediate element 928 may be manufactured by cold-forming or forging. Other configurations are contemplated.
- the tenth embodiment of the tappet assembly 1008 is shown. As will be appreciated from the subsequent description below, the tenth embodiment is similar to the first embodiment of the tappet assembly 108 described above in connection with Figures 2-8. As such, the components and structural features of the tenth embodiment of the tappet assembly that are the same as or that otherwise correspond to the first embodiment of the tappet assembly 108 are provided with the same reference numerals increased by 900. While the specific differences between these embodiments will be described in detail, for the purposes of clarity and consistency, only certain structural features and components common between these embodiments will be discussed and depicted in the drawing(s) of the tenth embodiment of the tappet assembly 1008.
- the tappet assembly 1008 includes a follower assembly 1026, an intermediate element 1028, and a tappet body 1030, each of which will be described in greater detail below.
- the tappet body 1030 of the tappet assembly 1008 has a generally cylindrical shape and defines an outer surface 1032 and an inner surface 1034, each of which have a generally annular profile.
- Two indented walls 1036 are formed on opposite sides of the tappet body 1030.
- An aperture 1038 is formed in each indented wall 1036 extending from the outer surface 1032 to the inner surface 1034.
- the apertures 1038 each have a substantially circular profile, are aligned with each other about an aperture axis Al, and cooperate to support the follower assembly 1026 in a manner similar to that described above.
- An ear 1037 may be formed on each indented wall 1036 that extends beneath the tappet body 1030 to provide greater strength to the tappet body 1030.
- the tappet body 1030 of the tappet assembly 1008 also comprises at least one seat 1040 (shown partially in phantom), which is likewise formed extending from the outer surface 1032 to the inner surface 1034 (see also Figure 20).
- the seat 1040 is arranged on a seat axis A2, which is perpendicular to and spaced from the aperture axis Al .
- the seat 1040 has a generally rectangular profile that is configured to support the intermediate element 1028.
- the intermediate element 1028 of the follower assembly 1026 includes a central portion 1052, a platform 1054, and at least one protrusion 1056.
- the platform 1054 is formed on the central portion 1052 of the intermediate element 1028 and provides a contact surface that is arranged to engage the spring-loaded piston 122 of the high-pressure fuel pump assembly 104 in force translating relationship (see Figure 5; engagement not shown).
- the protrusion 1056 extends from the central portion 1052 generally away from the platform 1054 to a distance beyond the bearings 1044A, 1044B.
- a bore 1058 is further formed in the central portion 1052 and is configured to receive the shaft 1042 of the follower assembly 1026.
- the platform 1054 is disposed slightly above the protrusion 1056 and spaced from the bore 1058 such that the platform 1054 is spaced from the bearings 1044A, 1044B and the protrusion 1056 is arranged between the bore 1058 and the platform 1054.
- the platform 1054 extends outwardly in a generally radial direction toward the tappet body 1030, allowing the contact surface between the spring-loaded piston 122 of the high-pressure fuel pump assembly 104 to be enlarged.
- the protrusion 1056 has a generally rectangular profile and is configured to be disposed or otherwise accommodated by the seat 1040 of the tappet body 1030 (see Figure 20).
- the intermediate element 1028 further comprises a guide tip 1060 extending from the protrusion 1056, through the seat 1040, and protruding from the tappet body 1030.
- the guide tip 1060 protrudes beyond the outer surface 1032 of the tappet body 1030 to be received in, and travel along, the guide slot 118 of the housing 106 (see Figure 3).
- This configuration indexes the tappet assembly 1008 within the tappet cylinder 116 and prevents rotation of the tappet assembly 1008 with respect to the camshaft lobe 102 and the high-pressure fuel pump assembly 104, as discussed above.
- the embodiments of the tappet assembly of the present invention significantly reduce the cost and complexity of manufacturing and assembling high-pressure fuel systems 100 and associated components. Specifically, it will be appreciated that the cooperation between the intermediate element, the bearings, and the shaft of the follower assembly, and the tappet body promote reduced mass and increased stiffness without compromising performance. Further, it will be appreciated that the embodiments of the tappet assembly of the present invention afford opportunities for high-pressure fuel systems 100 with superior operational characteristics, such as improved performance, component life and longevity, efficiency, weight, load and stress capability, and packaging orientation.
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Valve-Gear Or Valve Arrangements (AREA)
- Fuel-Injection Apparatus (AREA)
Abstract
L'invention concerne un ensemble poussoir destiné à être utilisé dans la translation d'une force entre un lobe d'arbre à cames et un ensemble pompe à carburant par l'intermédiaire d'un mouvement de va-et-vient à l'intérieur d'un cylindre de poussoir ayant une fente de guidage. L'ensemble poussoir comprend un corps de poussoir définissant une paire d'ouvertures et au moins un siège, et un ensemble suiveur. L'ensemble suiveur a un arbre, un premier palier et un second palier supportés chacun sur l'arbre pour venir en prise avec le lobe d'arbre à cames. Un élément intermédiaire est en outre supporté sur l'arbre entre les premier et second paliers et a une plateforme pour venir en prise avec l'ensemble pompe à carburant. L'élément intermédiaire est au moins partiellement disposé dans ledit siège du corps de poussoir et l'arbre est disposé dans la paire d'ouvertures du corps de poussoir.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
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PCT/US2019/038723 WO2020263216A1 (fr) | 2019-06-24 | 2019-06-24 | Ensemble poussoir destiné à être utilisé dans un système de carburant haute pression d'un moteur à combustion interne |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
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PCT/US2019/038723 WO2020263216A1 (fr) | 2019-06-24 | 2019-06-24 | Ensemble poussoir destiné à être utilisé dans un système de carburant haute pression d'un moteur à combustion interne |
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WO2020263216A1 true WO2020263216A1 (fr) | 2020-12-30 |
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PCT/US2019/038723 WO2020263216A1 (fr) | 2019-06-24 | 2019-06-24 | Ensemble poussoir destiné à être utilisé dans un système de carburant haute pression d'un moteur à combustion interne |
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Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH11294117A (ja) * | 1998-04-07 | 1999-10-26 | Fuji Oozx Inc | 内燃機関用タペット |
US8863716B2 (en) * | 2010-07-07 | 2014-10-21 | Schaeffler Technologies Gmbh & Co. Kg | Tappet |
CN105863919A (zh) * | 2016-05-25 | 2016-08-17 | 杭州新坐标科技股份有限公司 | 一种高压油泵滚子挺柱 |
JP2018044506A (ja) * | 2016-09-16 | 2018-03-22 | 株式会社オティックス | ローラリフタ |
US20180202402A1 (en) * | 2015-07-15 | 2018-07-19 | GT Technologies | Tappet assembly for use in an internal combustion engine high-pressure fuel system |
-
2019
- 2019-06-24 WO PCT/US2019/038723 patent/WO2020263216A1/fr active Application Filing
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH11294117A (ja) * | 1998-04-07 | 1999-10-26 | Fuji Oozx Inc | 内燃機関用タペット |
US8863716B2 (en) * | 2010-07-07 | 2014-10-21 | Schaeffler Technologies Gmbh & Co. Kg | Tappet |
US20180202402A1 (en) * | 2015-07-15 | 2018-07-19 | GT Technologies | Tappet assembly for use in an internal combustion engine high-pressure fuel system |
CN105863919A (zh) * | 2016-05-25 | 2016-08-17 | 杭州新坐标科技股份有限公司 | 一种高压油泵滚子挺柱 |
JP2018044506A (ja) * | 2016-09-16 | 2018-03-22 | 株式会社オティックス | ローラリフタ |
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