Abstract: A mechanical system comprising: a tappet, including a body; an insert mounted in the body; a pin extending along a first axis; and a roller element movable in rotation relative to the pin around the first axis. The insert supports the pin, while the body supports the insert, along at least one first direction parallel to a second axis which is perpendicular to the first axis. The mechanical system can be integrated into an injection pump and/or a valve actuator.

Abstract: A rocker shaft for a valve train of an internal combustion engine, including: a substantially cylindrical outer circumferential surface; and a layer of amorphous hydrocarbon deposited on the substantially cylindrical outer circumferential surface. The rocker shaft is arranged to engage a rocker arm such that the rocker arm is at least partially rotatable about the rocker shaft. A method of forming rocker shaft for a valve train of an internal combustion engine, including: forming a substantially cylindrical outer circumferential surface; and depositing a layer of amorphous hydrocarbon on the substantially cylindrical outer circumferential surface. The rocker shaft is arranged to engage a rocker arm such that the rocker arm is at least partially rotatable about the rocker shaft.

Abstract: A drag lever for actuating a gas exchange valve of an internal combustion engine. The drag lever includes an oblong lever body formed of sheet metal material, wherein the lever body has a bottom and side walls integrally formed at an angle of about 90° onto the bottom on both sides. A first end section of the lever body includes a joint socket formed into the bottom between the side walls. The joint socket serves to pivotally moveably support the drag lever on a joint head mounted stationary in the internal combustion engine. A middle section of the lever body is provided with a cam gripping surface, and a second end section of the lever body has a contact surface extending on the bottom. The contact surface serves for actuating the gas exchange valve. The lever body is dimensioned so as to have essentially the same width in a cross section through the joint socket and in a cross section through the middle section.

Abstract: A detent structure for a rocker shaft includes a camshaft, a rocker shaft, a shaft support, and a detent part. The camshaft is provided at a cylinder head of an engine. The shaft support is provided at the cylinder head to support the rocker shaft and has a support surface supporting the rocker shaft. The detent part is to prevent rotation of the rocker shaft. The detent part includes a bolt insertion hole and a detent bolt. The bolt insertion hole is displaced from a central axis of the rocker shaft and passes through the rocker shaft. The detent bolt is provided in the bolt insertion hole and is fastened to the shaft support to pass across the support surface.

Abstract: The invention relates to a finger follower, or lever (1) of a valve train, for example of a piston-type internal combustion engine, with a lever body (2) having an end-sided base web (4), on which there is a spherical cap-shaped bearing cup (8) for an articulated mounting on a bearing pin of a housing-sided support element, said bearing pin terminating as a spherical cap; and on this base web is fastened a retaining clamp (9), engaging with an annular groove of the bearing pin, in order to secure the finger follower (1) on the support element in such a way that said finger follower can move to a limited extent.

Abstract: A method of manufacturing outer arms of a three arm spring over pivot switchable roller finger follower. The method includes the steps of forming the outer arms of the switchable roller finger follower as a single unit, forming a material web between the outer arms, and separating the outer arms apart from each other. Also, an intermediate assembly of the outer arms of the three arm spring over pivot switchable roller finger follower is disclosed. The intermediate assembly has a first outer arm, a second outer arm, and a material web which extends between the outer arms, and adjoins the outer arms together.

Abstract: A method of manufacturing spring pallets of a switchable roller finger follower. The method includes the steps of forming the spring pallets of the roller finger follower as a single unit, forming a material web between the spring pallets, and separating the spring pallets apart from each other. Also, an intermediate assembly of the spring pallets of the roller finger follower is disclosed. The intermediate assembly includes a first spring pallet, a second spring pallet, and a material web which extends between the spring pallets, and adjoins the spring pallets together. Further, a method of manufacturing an inner arm of the switchable roller finger follower is disclosed in which the inner arm is formed by sheet metal, preferably by stamping.

Abstract: The finger follower employs two independent lost motion arms and a rod which moves longitudinally to lock both arms. The rod is transversely mounted in the follower. In order to avoid premature locking, each arm has a chamfered surface on a top wall to force the rod out of engagement with the arm during upward movement of the arms, to protect premature movement of the rod from an unlocked position to a locked position.

Abstract: The invention proposes a switchable finger lever (1) comprising an inner lever (2) comprising on one end (4), a support (5) for a gas exchange valve and on another end (6), a contact surface (7) for a head of a support element, said inner lever (2) comprising on the one end (4), pivotable outer arms (8) made separately from each other, which outer arms (8) comprise on their upper sides (10), contacting surfaces (11) for high lift cams, a coupling device (12) comprising a coupling slide (13) for simultaneously connecting the outer arms (8) to the inner lever (2) being seated in a section of the another end (6) in the inner lever (2), which coupling slide (13) is seated in an oblong hole (14) extending transversely through the inner lever (2) as also in longitudinal direction of the finger lever (2), the coupling slide (13) comprises two end portions (15) which protrude beyond the outer walls (9),and for effecting coupling, the coupling slide (13) can be displaced with the two end portions (15) partially under

Abstract: An engine assembly may include an engine structure supporting a camshaft and a valve lift mechanism. The camshaft may include a cam lobe and may define a longitudinally extending rotational axis. The valve lift mechanism may define a longitudinally extending cam engagement surface and a first side wall. The cam engagement surface may be engaged with the cam lobe at a first location. The first side wall may be fixed to the cam engagement surface and may include first and second portions. The first portion may extend from the cam engagement surface. The second portion may extend continuously inward from an end of the first portion. The inward extent of the second portion may be greater than or equal to a first height at the first location defined from the cam engagement surface to the end of the first portion.

Abstract: An object of the present invention is to provide a compact and low cost cam follower by using a strong stud which does not have severed fiber flow due to cutting process and has a continuous fiber flow throughout all portions. A cam follower is constituted by an outer ring which has an outer track surface in its inner circumference; a stud which has an inner track surface opposed to the outer track surface, a flange portion abutting on one side of the inner track surface, a side plate fitting portion and a mounting shaft portion abutting on another side of the inner track surface in this order, and a fiber flow formed continuously from the flange portion to the inner track surface along their outer circumferences; rolling elements which are arranged between the outer track surface and inner track surface; and an inner side plate which is pressed into the side plate fitting portion to work with the flange portion for limiting axial movement of the outer ring and the rolling elements.

Abstract: A cam follower for a valve drive of an internal combustion engine. The cam follower has a housing and a cam roller. The cam roller is arranged between the side walls of the housing and is mounted on a journal which bridges the side walls. The cam roller, which has an outer ring, a rolling body set and an inner ring, is a combined plain and rolling bearing. The outer ring and the inner ring are in sliding contact with one another, and the rolling body set is arranged between the inner ring and the journal.

Abstract: One possible embodiment of the invention is essentially an apparatus and methodology for mounting a rocker arm assembly to a cylinder head of an internal combustion engine comprising of at least a unitary stanchion to which multiple rocker arms may be moveably connected. In least one embodiment, the unitary stanchion may comprise a base from which project multiple rows of pedestals. Two of more of these rows may be set in essentially parallel orientation, which further defines a primary space in which a portion of the rocker arm is located. The unitary stanchion may be secured to the cylinder head thorough multiple rows of fasteners. The footprint of the base of unitary stanchion could allow the unitary stanchion to possibly act as generally efficient external buttress for generally providing greater support across the top of the cylinder head.

Abstract: The present invention provides a rocker arm manufacturing method capable of stably forming valve stem guide walls. In the method according to the present invention, an intermediate product 13 having both side walls 20 extended in a predetermined direction and arranged in parallel with each other and a one end side connection wall 30 connecting lower ends of both the side walls 20 at a longitudinal one end of the product is obtained. Next, a first pressing punch 70 is pressed against the outer surface portions of both the side walls 20 from the outside thereof to cause downward plastic flows of regions of the outer surface portions of both the side walls positioned below the cutout portions 31 to thereby form raising walls 32 in a downwardly protruded manner at both sides of the one end side connection wall 30. Thereafter, valve stem guide walls 35 are formed by pressing second pressing punches 80 against both the raising walls 32 of the one end side connection wall 30.

Abstract: A valve gear comprises a cylinder head, a supporting member fixed to the cylinder head, a rocker arm which is mounted on the supporting member so as to be placed on the latter, a substantially plate-shaped clip mountable to the rocker arm, the clip having a fitting hole in which an outer periphery of the supporting member is fitted so that the clip is prevented from falling off, a pair of walls which is formed on the rocker arm so as to be opposed to each other with the supporting member being located therebetween, and a pair of locking portions formed in inner faces of the walls so that outer edges of the clip are elastically engaged with the locking portions thereby to be locked, respectively.

Abstract: An internal combustion engine has one or more engine cylinders (12) within which fuel is combusted and a pair of cylinder valves (14, 16) spring-biased (22, 24) closed but open in unison to place the respective cylinder in flow communication with one of an intake and an exhaust. A bridge (34) bridges ends of the pair external to the cylinder and has a spherically concave depression (42) in a face that is opposite a face that bears against the ends of the pair. The depression is located intermediate locations at which the ends of the pair bear against the bridge. A pivot foot (44) has a spherically convex surface (46) seated with substantial conformity in the depression and a flat surface (48) opposite the spherically convex surface. The flat surface of the pivot foot abuts a flat surface (50) of a rocker (30) that when rocked acts through the pivot foot and bridge to open the respective pair of valves.

Abstract: An inner lever (1) for a switchable finger lever (2) of a valve train of an internal combustion engine is provided, having a box-like main part (5) with two lateral walls (6), which are connected at a first end (7) by a transverse bar (8), which intrinsically includes a driver surface (9) for a coupling slide that can be guided longitudinally by the outer lever (3), and opposite from the first end (7), the lateral walls (6) have two strongly crimped together, thin-walled arms (10), which each extend in the direction toward the second end (11) of the inner lever (1) to form a longitudinal bar (12). The arms contact each other with their inner sides (15), and between the lateral walls (6), a cam contact surface (16) can be provided. The inner lever (1) made from thin-walled steel sheet metal at least to a large extent using punch-bending techniques.

Abstract: A valve train for use in an engine is provided. The valve train includes a rocker arm assembly having a valve side arm and a cam side arm. A valve is coupled to the engine and is in contact with the valve side arm. A pushrod is reciprocatable by a camshaft and is in contact with the cam side arm. An overload feature is located on at least one of the rocker arm assembly or the pushrod. The overload feature has a reduced cross-sectional area calibrated to activate at a predefined load.

Abstract: A rocker arm includes a first end including a substantially horizontal wall having a receptacle formed therein. A second end of the rocker arm is spaced from the first end and includes a substantially horizontal wall for engaging a valve stem. A pair of spaced substantially parallel vertical sidewalls extend between the first end and the second end. In one embodiment, the sidewalls define a width between the first end and the second end that is less than each of the widths of the first and second ends. In another embodiment, a transverse wall extending between the sidewalls is formed in the second end. In yet another embodiment, rocker arm alignment walls are formed in the second end independently of the sidewalls.

Abstract: In a gas exchange valve operating apparatus with at least one overhead camshaft for actuating the gas exchange valves, with a hydraulic medium supply passage extending through the camshaft and with at least one hydraulic switchable support unit cooperating with a lever-like cam follower which is disposed on a switchable support unit and on a gas exchange valve and is furthermore in contact with the overhead camshaft, the support unit is disposed in communication with at least one pressure medium supplied via the hydraulic medium supply passage of the camshaft.

Abstract: According to the present invention, an outer lever (1) of a finger lever (2) that can be switched to different lifts for at least one gas exchange valve is made by a deep drawing method. A salient feature of the invention is that through a special trimming operation of the cup-shaped base body (16) that is formed in a first step of the method, running contact surfaces (14, 15) for cams, preferably high-lift cams, are generated on upper sides (12, 13) of arms (4, 5) of the outer lever (1). Through the deep drawing method of the invention, only relatively low fabrication costs are to be expected.

Abstract: The present invention provides a rocker arm manufacturing method capable of improving the durability and excellent in productivity. In the method according to the present invention, an intermediate product 13 having both side walls 20 extended in a predetermined direction and arranged in parallel with each other and one end side connection wall 30 connecting lower ends of a longitudinal one end of both the side walls is obtained. Next, both side walls 20 formed at the one end of the intermediate product 13 are inwardly bent. Thereafter, ironing dies 60 are pressed down against outer surfaces of both the inclined side walls 20 from an upper side to a lower side to execute ironing of outer surface portions of both the side walls 20 to downwardly plastically fluidize the constituent material of both the side walls 20 to thereby form valve stem guide walls 35 at both sides of the one end side connection wall 30 in a downwardly protruded manner.

Abstract: According to the present invention, an outer lever (1) of a finger lever (2) that can be switched to different lifts for at least one gas exchange valve is made by a deep drawing method. A salient feature of the invention is that a cup-shaped base body (16) having an inverse U-shaped cross-section is deep drawn, and opposing running contact surfaces (14, 15) for high-lift cams are created on arms (4, 5) of the outer lever (1) by punching out a bottom (19) of the base body (16). Through the deep drawing method of the invention, only relatively low fabrication costs are to be expected.

Abstract: A rocker arm is mounted to an eccentric shaft. The shaft has a pair of ends which are mounted to corresponding supports. The shaft has a rocker arm seat portion which is eccentric to the end portions, whereby when the position of the shaft is changed by rotating it, the position of the rocker arm changes. The shaft ends are mounted to riser blocks which are connected to a support structure. The shaft ends may be clamped in a fixed position relative to the riser blocks, or unclamped to permit the shaft to be rotated. When rotated, the position of the rocker arm may be changed up or down relative to the support structure and a valve stem which the rocker arm is intended to engage, thereby adjusting valve clearance.

Abstract: Connecting element (10) retains cam follower (2), which actuates gas-exchange valve (4) of an internal combustion engine, on support element (6). Support element (6) has spherical end (7) on cylindrical section (22) and on which cam follower (2) is mounted, so as to be pivotably movable in the direction of gas-exchange valve (4) about center of rotation (9). Connecting element (10) has elastically deformable projections (21), which proceed from central webs (19), parallel to the pivot axis of cam follower (2) such that connecting element (10) is connected to cylindrical section (22) in a frictionally-engaging manner. Projections (21) are embodied as lugs (20) which angle away from central webs (19) and extend in a direction pointing away from cam follower (2), so that projections (21) are elastic in shape.

Abstract: A rocker arm formed of material in a shape of sheet has a pair of side wall portions, a connection portion for a valve stem receiving portion and a connection portion for a pivot receiving portion which interconnect the side wall portions, and an open portion for arranging a roller which is formed between the two connection portions. A distance between outer side surfaces of the pair of side wall portions in the connection portion for the valve stem receiving portion is reduced in a direction from upper edges to lower edges in a step-like shape having two or more step differences, whereby a first outer side surface and a second outer side surface are formed.

Abstract: A corrosion-resistant alloy tube is formed and bonded to a pre-machined steel alloy rod to form a riser tensioner cylinder rod. During assembly, an epoxy is injected into an annular space between the tube and rod and then cured. The bonded tube is ground to a desired surface finish prior to installation and utilizes a double seal arrangement that prevents external pressure or corrosive fluids from entering the cured epoxy in the annular space.

Abstract: A rocker arm that is rockably attached to a cylinder head actuates a valve by a guide groove that is formed at an end thereof engaging with an upper end of a valve stem, and a roller that is mounted in a roller housing portion of the arm main unit contacting against a cam and rocking. The guide groove is formed by press working ends of the arm main unit in the thickness direction of the plate material to form a pair of walls, and thereafter applying sandwiching pressure in the lateral direction to the walls to increase the height thereof.

Abstract: A rocker arm configured to be supported by a support portion of an internal-combustion engine and to be driven in a swinging manner by a cam. The rocker arm includes a rocker arm body including a cam follower having a first slide-contact surface, wherein the first slide-contact surface is in sliding contact with the cam, a fulcrum portion including a second slide-contact surface, wherein the second slide-contact surface swingably is in sliding contact with respect to the support portion, and a lubricant discharging portion for biasing a lubricant supplied from the fulcrum portion in a direction toward the first slide-contact surface and discharging the lubricant. The fulcrum portion penetrates the rocker arm and is fastened to the rocker arm body. The fulcrum portion has a through hole supplying the lubricant to the lubricant discharging portion through the rocker arm body.

Abstract: A rocker box, pushrod assembly, oil delivery system, tappets and tappet guides are provided for an engine, particularly a motorcycle engine. The rocker box includes a separable upper portion and lower portion with a seal for sealing the upper portion and lower portion when coupled together. The pushrod assembly includes an adjusting unit that collapses into a pushrod shaft. The oil delivery system includes an oil passageway(s) in a rocker shaft of a rocker arm assembly, and at least one of an oil passageway(s) in a rocker box and an oil passageway(s) in a pushrod assembly.

Abstract: A method for manufacturing according to the present invention includes a step of obtaining a bent workpiece 13 with prepared apertures 21 and 21, wherein the bent work piece 13 includes a pair of side walls 20 and 20 disposed in parallel with each other and connecting walls 30 and 40 for connecting the side walls 20 and 20, the pair of side walls 20 an d20 each having a prepared aperture 21, and a step of forming a roller supporting shaft fixing aperture 25 by inserting a sizing punch 60 into the prepared aperture 21, wherein the sizing punch 60 has a tapered push enlarging portion 61 at a tip end portion, a basal end side of the push enlarging portion being larger than the prepared aperture 21 in diameter, and a tip end side of the push enlarging portion 61 being smaller than the prepared aperture 21 in diameter, whereby the push enlarging portion 61 causes plastic flow of an inner peripheral portion of the prepared aperture to finish the inner peripheral surface of the prepared aperture to thereby obtain a

Abstract: A rolling bearing for a rocker arm includes an outer ring in rolling contact with a cam of an engine, an outer-ring shaft placed inside the outer ring and fixed to the rocker arm, and a plurality of rollers provided between the outer ring and the outer-ring shaft. At least one of the outer ring, the outer-ring shaft and the rolling elements has a nitrogen-rich layer, an austenite crystal grain size number in a range exceeding 10, and a surface hardness Hv of at least 653. Thus, the life can be extended.

Abstract: An internal combustion engine with selectively deactivated intake and/or exhaust valves includes a fulcrum plate having a through hole with a slidable plunger supporting a pivot ball that engages an associated rocker arm. A solenoid positioned above the rocker arm cover is directly coupled to a latching mechanism that either allows or prevents sliding movement of the plunger to selectively deactivate associated intake/exhaust valves. When in the valve activated position, the rocker arm pivots about the pivot ball and opens the valve. When in the valve deactivated position, the plunger retracts at least partially into the fulcrum plate so that the rocker arm motion is insufficient to open the associated valve. A lost motion torsional spring acts on the plunger to provide an opposing force to the rocker arm and to return the plunger to the valve activated position during the base circle portion of camshaft rotation.

Abstract: The present invention provides a rocker arm manufacturing method capable of stably forming valve stem guide walls. In the method according to the present invention, an intermediate product 13 having both side walls 20 extended in a predetermined direction and arranged in parallel with each other and a one end side connection wall 30 connecting lower ends of both the side walls 20 at a longitudinal one end of the product is obtained. Next, a first pressing punch 70 is pressed against the outer surface portions of both the side walls 20 from the outside thereof to cause downward plastic flows of regions of the outer surface portions of both the side walls positioned below the cutout portions 31 to thereby form raising walls 32 in a downwardly protruded manner at both sides of the one end side connection wall 30. Thereafter, valve stem guide walls 35 are formed by pressing second pressing punches 80 against both the raising walls 32 of the one end side connection wall 30.

Abstract: The present invention is a shaft-mounted rocker arm arrangement for an internal combustion engine which provides simplified assembly and disassembly by allowing individual rocker arms to be added or removed separately and without removing the rocker shaft. The present invention utilizes a rocker shaft and a rocker arm rotatably coupled to the rocker shaft. The rocker shaft includes a flat portion arranged to receive the rocker arm. The rocker arm includes a body portion and a curved arm portion arranged to match a curvature of the rocker shaft, and arranged to engage more than 180 degrees of the rocker shaft.

Abstract: A valve control mechanism is provided for an overhead valve, internal combustion engine having a camshaft moving a pushrod to move a rocker arm that in turn moves the valve. Three aligned rollers are fastened to the end of the pushrod adjacent the rocker arm. The outer two rollers roll along parallel profiled surfaces that control at least the valve lift and ramp. The middle roller rolls along an engaging surface on the rocker to move the rocker arm in a motion determined by the configuration and location of the profiled surfaces and the engaging first and second rollers. The outer rollers rotate in a direction opposite the middle roller.

Abstract: The present invention provides a rocker arm manufacturing method capable of improving the durability and excellent in productivity. In the method according to the present invention, an intermediate product 13 having both side walls 20 extended in a predetermined direction and arranged in parallel with each other and one end side connection wall 30 connecting lower ends of a longitudinal one end of both the side walls is obtained. Next, both side walls 20 formed at the one end of the intermediate product 13 are inwardly bent. Thereafter, ironing dies 60 are pressed down against outer surfaces of both the inclined side walls 20 from an upper side to a lower side to execute ironing of outer surface portions of both the side walls 20 to downwardly plastically fluidize the constituent material of both the side walls 20 to thereby form valve stem guide walls 35 at both sides of the one end side connection wall 30 in a downwardly protruded manner.

Abstract: A rocker arm includes a first end including a substantially horizontal wall having a receptacle formed therein. A second end of the rocker arm is spaced from the first end and includes a substantially horizontal wall for engaging a valve stem. A pair of spaced substantially parallel vertical sidewalls extend between the first end and the second end. In one embodiment, the sidewalls define a width between the first end and the second end that is less than each of the widths of the first and second ends. In another embodiment, a transverse wall extending between the sidewalls is formed in the second end. In yet another embodiment, rocker arm alignment walls are formed in the second end independently of the sidewalls.

Abstract: Cam actuated systems, such as valve trains for an engine, typically bring cam lobe action to the engine valve via a linkage that includes a cam actuated roller assembly which may be either a rocker or a lifter. These cam actuated rocker assemblies include a housing with a pair of arms with roller support bores there through. A roller support pin is received in the roller support bores, and rotationally supports a roller mounted about the roller pin and between the arms of the housing. The roller pin may include a relatively hard and inexpensive core, such as steel, cladded with a relatively soft more expensive metal, such as bronze.

Abstract: The lever (11) is fitted with two rollers (20A, 20B) which are supported by a core (21) provided with a mounting bore (21B) on an articulated shaft, wherein the rollers (20A, 20B) are both mounted between two webs of a pair of webs which are added to the core (21). The webs (22A, 23B) are on the whole planar. A first web (22A) of each pair of webs is partially engaged in a hollow housing (21C) created on the lateral surface (21D) of the core (21). The second web (23B) of the same pair is maintained at a distance from the first web. The hollow housings (21C) are created on the two opposite lateral surfaces (21D) of the core (21) of the lever (11).

Abstract: A rocker arm and method for manufacture is provided whereby the rocker arm is manufactured in two halves generally symmetric to a central plane. The mating surface of one or both rocker arm halves incorporate grooves which upon assembly provide passageways which may follow any desired pathway for lubricant and or afford a reduction in mass and/or an increase in structural stiffness. The two halves are preferably joined together by metallurgical brazing or by other chemical or mechanical means.

Abstract: An internal combustion engine having a plurality of intake and/or exhaust valves associated with each cylinder includes a valvetrain having a fulcrum with a plurality of pivot ball sockets each associated with a rocker arm and pivot ball disposed between the fulcrum and the rocker arm with the fulcrum extending through apertures of the rocker arms and having a plurality of slots, each slot having generally parallel opposing lateral surfaces for receiving and guiding both sides of an associated rocker arm so the rocker arm pivots about the pivot ball in a plane of the rocker arm. The fulcrum can accommodate at least two rocker arms that may operate in non-parallel planes relative to one another and can include bearing and locating surfaces integrally formed to finish dimensions to eliminate machining.

Abstract: According to the present invention, an outer lever (1) of a finger lever (2) that can be switched to different lifts for at least one gas exchange valve is made by a deep drawing method. A salient feature of the invention is that a cup-shaped base body (16) having an inverse U-shaped cross-section is deep drawn, and opposing running contact surfaces (14, 15) for high-lift cams are created on arms (4, 5) of the outer lever (1) by punching out a bottom (19) of the base body (16). Through the deep drawing method of the invention, only relatively low fabrication costs are to be expected.

Abstract: The present invention provides an improved rocker arm system for actuating poppet valves in high performance internal combustion engines. The rocker arm provides trunnion journals extending from each side fitted to outboard bearing mounts to guide the motion of the rocker arm. An I-beam rocker arm having high stiffness and low mass is disclosed.

Abstract: Disclosed is a unique configuration of a rocker arm per se wherein high stress areas thereof are strengthened and a trunion shaft is rotatively mounted on its push rod end and has a threaded push rod end insertion bore, a unique push rod construction per se wherein the upper end thereof is threaded, the combination of this rocker arm and the push rod wherein the upper end of the push rod is threaded into the insertion bore whereby the sudden, rapid, repeated and severe impact forces of the push rod end against the rocker arm are spread throughout the threaded connection and the rocker arm and are thus greatly diminished for each point of force contact between the push rod and the rocker arm, and further the stated combination mounted on an internal combustion engine.

Abstract: There is provided a cam follower in which a surface roughness of an outer surface of a roller of a cam follower which is in rolling contact with a cam of an engine is obtained individually in an axial direction and a circumferential direction, a skewness Rsk of a profile is formed to be negative, a core roughness depth Rk is made to be 0.3 or less, a reduced valley depth Rvk is made to be 0.3 or less, and a ratio Rk/Rt of the Rk to a maximum height Rt of the profile is made to be 0.19 or more.

Abstract: The present invention provides a method of manufacturing a rocker arm, having a process of rough processing, in which a metallic stock is subjected to compression-forming by cold forging to form a connecting portion, side wall lower portions of two side wall portions, and two projecting portions projecting beyond a rocker arm width outwardly from the side wall lower portions, and to form, at tip ends of the side wall lower portions, two stem guides projecting downwardly lower than a pat surface level of the connecting portion, a process of formation of a side wall, in which at least a part of the two projecting portions is subjected to ironing processing to form side wall upper portions of the two side wall portions, thereby forming the two side wall portions accommodated in a rocker arm width, and a process of working of a stem guide, in which the two side wall portions are subjected to ironing processing from outer surface sides, thereby increasing a projection height from which the stem guides project down

Abstract: There is provided a rocker arm of a kind in which even though the rocker arm is manufactured by the use of a press working technique the arm width can be minimized while the flat outer surface region of a required width is secured on an outer surface of the connecting wall, thereby contributing to reduction in size and weight of the rocker arm. This rocker arm is capable of being driven by a cam for selectively opening and closing a valve of an internal combustion engine. This rocker arm includes an arm body prepared by bending a single plate material to represent a generally inverted U-shaped section including opposite side walls and a connecting wall bridging between the opposite side walls. A roller engageable with the cam is rotatably mounted on a portion of the arm body generally intermediate of the length thereof.

Abstract: A rocker arm includes: a body that is made of sheet metal and includes a pair of side walls; and a pair of axial holes that are respectively formed through the pair of side walls and have a first diameter and through which an axis is inserted. The pair of axial holes include thickened portions formed partially or overall of circumference of the pair of axial holes, and the thickened portion is formed by expanding a hole that has a second diameter smaller than the first diameter and is formed in a pre-arranged range for forming the axial hole in a blank material so as to causing plastic flow in a metallic material of the circumference of the hole.

Abstract: A rocker arm 1 made of sheet metal is formed so that Vickers hardness Hv of the surface layer portion 9a of the valve stem receiver 9 is set at Hv 650 to 800 and a quantity of the retained austenite ?R is set at 25 to 35 vol %.