EP2003295A2 - Dispositif de poussoir de soupape - Google Patents

Dispositif de poussoir de soupape Download PDF

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Publication number
EP2003295A2
EP2003295A2 EP07740682A EP07740682A EP2003295A2 EP 2003295 A2 EP2003295 A2 EP 2003295A2 EP 07740682 A EP07740682 A EP 07740682A EP 07740682 A EP07740682 A EP 07740682A EP 2003295 A2 EP2003295 A2 EP 2003295A2
Authority
EP
European Patent Office
Prior art keywords
rocker arms
portions
end portions
pair
cam follower
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP07740682A
Other languages
German (de)
English (en)
Inventor
Noriyuki Takeo
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
NSK Ltd
Original Assignee
NSK Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from JP2006238741A external-priority patent/JP2008057514A/ja
Priority claimed from JP2006282123A external-priority patent/JP2007292042A/ja
Application filed by NSK Ltd filed Critical NSK Ltd
Publication of EP2003295A2 publication Critical patent/EP2003295A2/fr
Withdrawn legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
    • F01L1/00—Valve-gear or valve arrangements, e.g. lift-valve gear
    • F01L1/26—Valve-gear or valve arrangements, e.g. lift-valve gear characterised by the provision of two or more valves operated simultaneously by same transmitting-gear; peculiar to machines or engines with more than two lift-valves per cylinder
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
    • F01L1/00—Valve-gear or valve arrangements, e.g. lift-valve gear
    • F01L1/12—Transmitting gear between valve drive and valve
    • F01L1/18—Rocking arms or levers
    • F01L1/181—Centre pivot rocking arms
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
    • F01L1/00—Valve-gear or valve arrangements, e.g. lift-valve gear
    • F01L1/12—Transmitting gear between valve drive and valve
    • F01L1/18—Rocking arms or levers
    • F01L1/185—Overhead end-pivot rocking arms
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
    • F01L1/00—Valve-gear or valve arrangements, e.g. lift-valve gear
    • F01L1/20—Adjusting or compensating clearance
    • F01L1/22—Adjusting or compensating clearance automatically, e.g. mechanically
    • F01L1/24—Adjusting or compensating clearance automatically, e.g. mechanically by fluid means, e.g. hydraulically
    • F01L1/2405—Adjusting or compensating clearance automatically, e.g. mechanically by fluid means, e.g. hydraulically by means of a hydraulic adjusting device located between the cylinder head and rocker arm
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
    • F01L2301/00—Using particular materials
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
    • F01L2303/00—Manufacturing of components used in valve arrangements
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
    • F01L2305/00—Valve arrangements comprising rollers

Definitions

  • a cam follower device is built in a valve train of an engine such as, for example, a three-valve engine, four-valve engine or five-valve engine in which the number of at least either of inlet valves and exhaust valves which are provided for one cylinder is two or more for converting rotation of a camshaft into a reciprocating motion of the two inlet valves or two exhaust valves.
  • an engine such as, for example, a three-valve engine, four-valve engine or five-valve engine in which the number of at least either of inlet valves and exhaust valves which are provided for one cylinder is two or more for converting rotation of a camshaft into a reciprocating motion of the two inlet valves or two exhaust valves.
  • an inlet valve and an exhaust valve which are adapted to open and close in synchronism with rotation of a crankshaft are provided in reciprocating engines (reciprocating piston engines).
  • reciprocating engines like these, the movement of the camshafts which rotate in synchronism with rotation of the crankshaft (at one half crankshaft speed in the case of a four-cycle engine) is transmitted to the inlet valve and the exhaust valve by rocker arms, so as to cause the inlet valve and the exhaust valve to reciprocated in an axial direction.
  • Figs. 30 to 31 show a conventional cam follower device which is described in Patent Document No. 1 as a first example of a conventional construction of a cam follower device which includes the rocker arm and the tappet roller described above.
  • a rocker arm 3 constituting the cam follower device is provided at a portion which confronts a cam 2 fixedly provided on a camshaft 1 which rotates in synchronism with a crankshaft of an engine.
  • a rocker arm shaft 5, which is a stationary shaft provided parallel to the camshaft 1, is inserted into a through hole 4 formed in an intermediate portion of the rocker arm 3. This configuration enables a swinging displacement of the rocker arm 3 about the rocker arm shaft 5.
  • a pair of support wall portions 6, 6 which are parallel to each other is provided at one end portion (a right end portion in Fig. 30 ) of the rocker arm 3 as shown in detail in Fig. 31 .
  • a support shaft 7 is fixed to the one end portion so as to extend between the end portions.
  • both end portions of the support shaft 7 are fixedly fitted, respectively, in a pair of support holes 8, 8 formed in both the support wall portions 6, 6 in positions which are aligned with each other.
  • a tappet roller 9 is supported rotatably on the periphery of an intermediate portion of the support shaft 7 via a radial needle bearing 10. Then, an outer circumferential surface of this tappet roller 9 is brought into an outer circumferential surface of the cam 2.
  • a screw hole is provided at the other end portion (a left end portion in Fig. 30 ) of the rocker arm 3, and an adjustment screw 11 is fixedly screwed into this screw hole. Then, a distal end portion (a pressing portion) of the adjustment screw 11 is caused to strike a proximal end face of a valve element 12 which is an inlet valve or an exhaust valve.
  • the rocker arm 3 When the engine is running, the rocker arm 3 is displaced in a swinging fashion about a center (a fulcrum) of the rocker arm shaft 5 in accordance with rotation of the cam 2. Then, the rocker arm 3 reciprocates the valve element 12 in an axial direction by pressing force of the adjustment screw 11 and spring force of a return spring 13. As this time, the tappet roller 9 can reduce frictional force acting between the cam 2 and the rocker arm 3, and therefore, a reduction in fuel consumption rate when the engine is running can be realized.
  • Figs. 32 to 34 show a cam follower device which is also described in Patent Document No. 1 as a second example of a conventional construction of a cam follower device including the rocker arm and the tappet roller.
  • a rocker arm 3a in the cam follower device of the second example of conventional construction is formed by applying to a sheet metal, such as sheet steel, stamping process for removing unnecessary portions and plastic process such as drawing process for obtaining a desired shape.
  • rocker arm 3a includes a pair of support wall portions 6a, 6a which are parallel to each other, a first connecting portion 14 which connects one end portions (right end portions in Figs.
  • a tappet roller 9 is disposed between the support wall portions 6a, 6a and between the first and second connecting portions 14, 15. This tappet roller 9 is supported rotatably around the periphery of an intermediate portion of a support shaft 7 which is fixed directly or via radial needle bearing to the support wall portions 6a, 6a so as to extend therebetween.
  • both end portions of the support shaft 7 are fittingly fixed, respectively, in a pair of support holes 8 formed in both the support wall portions 6a, 6a in positions aligned with each other for fixing the support shaft 7 at both the support wall portions 6a, 6a.
  • a distal end face of a plunger 16 constituting a lash adjuster is caused to strike a spherically recessed portion (a receiving portion) provided on one side (a lower side in Fig. 34 ) of the first connecting portion 14 and a proximal end portion of the valve element 12 which is the inlet valve or the exhaust valve is caused to strike one side (a lower side in Fig. 34 ) of the second connecting portion 15 (the pressing portion).
  • an outer circumferential surface of a cam 2 fixedly provided at an intermediate portion of a camshaft 1 is brought into abutment with an outer circumferential surface of the tappet roller 9.
  • the rocker arm 3a When the engine is running, in accordance with rotation of the cam 2, the rocker arm 3a is displaced in a swinging fashion about an abutment portion between the distal end face of the plunger 16 and the spherically recessed portion as a center (a fulcrum) between states indicated by solid and chain lines in Fig. 34 , so as to reciprocate the valve element 12 in the axial direction by the pressing force of the second connecting portion 15 and the spring force of a return spring 13.
  • the tappet roller 9 can reduce frictional force acting between the cam 2 and the rocker arm 3a, and therefore, a reduction in fuel consumption rate when the engine is running can be realized.
  • both the support wall portions 6, 6 (6a, 6a) are formed integrally on the rocker arm 3 (3a), and a space between both the support wall portions 6, 6 (6a, 6a) cannot be expanded.
  • the conventional method is, after hardening only the outer circumferential surface of the intermediate portion of the support shaft 7 by induction hardening, while inwardly fitting both the end portions of the support shaft 7 are fitted, respectively, in insides of both the support holes 8, 8 without looseness and interference therebetween, outer circumferential edge portions of both end faces of the support shaft 7 are compressed to be expanded towards circumferential edge portions of openings of both the support holes 8, 8.
  • the fixing method of this type needs a number of steps and causes an increase in production costs.
  • valve train of the engine when only conventional cam follower devices like one that has been described above are used as cam follower devices that are to be built in the valve train, the same numbers of cams 2 and tappet rollers 9 as valve elements 12 are necessary.
  • the numbers of inlet valves and exhaust valves to be provided per cylinder are gradually increased such as two or three. Therefore, in configuring the valve train of such a multi-valve engine, when only conventional cam follower devices like one that has been described above are used, the number of components of the valve train becomes too many, and this easily calls for drawbacks of the valve train being made enlarged in size, heavy in weight, highly frictional and highly expensive in cost.
  • Patent Document No. 1 Japanese Patent Unexamined Publication JP-A-2004-100499
  • a cam follower device of the invention has been made in view of the situations described above and an object thereof is to realize a construction which can reduce the numbers of cams and tappet rollers which are used when configuring a valve train of a multi-valve engine.
  • the invention is attained by the following configurations.
  • the two inlet valves or the two exhaust valves can be opened and closed simultaneously only by providing the single cam and the single tappet roller.
  • the cam follower device that is to be built in the valve train, the cam follower device can realize a reduction in the number of components of the valve train, when compared with the above described conventional cam follower device. Consequently, the valve train can be made smaller in size (space saving) and lighter in weight and can realize reductions in friction and production costs.
  • the method of fittingly fixing both the end portions of the support shaft in the support holes the method of press fitting both the end portions of the support shaft in both the support holes can be adopted.
  • the outer circumferential surface of the support shaft ⁇ the inner ring raceway of the radial needle bearing (or the inner sliding surface of the slide bearing) for supporting the tappet roller rotatably ⁇ can be prevented from being damaged.
  • both the end portions of the support shaft can be press fitted, respectively, in the insides of both the support holes through the openings of the support holes which lie on sides thereof opposing to each other.
  • the step of press fitting both the end portions of the support shaft, respectively, in the pair of support holes it is not necessary to cause the support shaft to pass through the inside of either of the support holes while the intermediate portion of the support shaft is press fitted (fitted through interference fit) in either of the support holes.
  • the pair of rocker arms of the invention which can prevent the damage to the outer circumferential surface of the intermediate portion of the support shaft may be parts which are separate from each other. Further, the pair of rocker arms of the invention may be constructed such that although the pair of rocker arms are connected together by a connecting portion in at least one location so that the rocker arms are disabled from a relative displacement, a distance between the portions where the support holes are formed and the connecting portion is made relatively large so that the interval between the rocker arms can be expanded.
  • the cam follower device set forth under (3) in the event that the configurations set forth under (4), (5) are adopted, even if the interval between the proximal end faces of the two inlet valves or two exhaust valves which are to be pressed by the pair of pressing portions is made remarkably large compared with the axial dimension of the tappet roller, the pair of pressing portions which can press both the proximal end faces accurately can be provided and the intervals between both the axial end faces of the tappet roller and the inner surfaces of the pair of rocker arms can be made small sufficiently (the axial displacement permitted to the tappet roller can be controlled to the desired magnitude). In other words, it becomes unnecessary to increase the axial dimension of the tappet roller so as to match the interval between both the proximal end faces.
  • a sliding area relative to the outer circumferential surface of the rocker arm shaft can be secured sufficiently, whereby wear amount of the outer circumferential surface of the rocker arm shaft can be made sufficiently small. Accordingly, duration life of the rocker arm shaft can be increased.
  • the thickness of both the rocker arms can be made thinner by such an amount.
  • the cam follower device set forth under (7) is carried out and the configurations set forth under (8), (9) are adopted, even if the interval between the proximal end faces of the two inlet or exhaust valves to be pressed by the pair of pressing portions and the interval between the distal end faces of the pair of plungers to be made to strike the pair of receiving portions become remarkably large compared with the axial dimension of the tappet roller, the pair of pressing portions which can press both the proximal end faces accurately and the pair of receiving portions having both the distal end faces made to strike accurately can be provided and also the intervals between both the axial end faces of the tappet roller and the inner surfaces of the pair of rocker arms can be made small sufficiently (the axial displacement permitted to the tappet roller can be controlled to the desired magnitude). In other words, it becomes unnecessary to increase the axial dimension of the tappet roller so as to match the interval between both the proximal end faces and the interval between both the distal end faces.
  • FIGs. 1 to 4 show a first embodiment of the invention.
  • a cam follower device of this embodiment is built, for use, in a valve train of an engine (of an OHC or DOHC type) such as, for example, a three-valve engine, a four-valve engine or a fifth-valve engine in which the number of at least one of inlet valves and exhaust valves provided per cylinder is made to be two or more.
  • the cam follower device of the embodiment that is so designed includes a pair of plate-shaped rocker arms 17, 17 which are identical in shape and size to each other, a support shaft 7a and a tappet roller 9.
  • the pair of plate-shaped rocker arms 17, 17 is formed separately into a shape like a boomerang by applying stamping process to a sheet metal such as a sheet steel.
  • the two so formed rocker arms 17, 17 are disposed parallel to each other with a predetermined interval defined therebetween.
  • the support shaft 7a is fixed to one end portions (right end portions in Figs. 1 to 2 ) of both the rocker arms 17, 17 so as to be extended therebetween.
  • a pair of support holes 8a, 8a is formed concentric with each other in positions which are aligned with each other at the one end portions of both the rocker arms 17, 17.
  • both end portions of the support shaft 7a are press fitted, respectively, in insides of both the support holes 8a, 8a through openings of the support holes 8a, 8a which lie on sides thereof opposing to each other.
  • both the rocker arms 17, 17 prevent the relative swing between the rocker arms about the support shaft 7a effectively.
  • the tappet roller 9 is supported rotatably on an outer circumferential surface of an intermediate portion of the support shaft 7a via a radial needle bearing 10.
  • a pair of through holes 4, 4 which is concentric with each other is formed at intermediate portions of both the rocker arms 17, 17 in positions aligned with each other.
  • a pair of projecting portions 18, 18 (pressing portions) is provided on lower sides of the other end portions (left end portions in Figs. 1 to 2 ) of both the rocker arms 17, 17. Distal end faces of both the projecting portions 18, 18 are each made into a partially cylindrical surface.
  • the tappet roller 9 is adaptable to support the tappet roller 9 rotatably on the circumference of the intermediate portion of the support shaft 7a via the radial rolling bearing such as the radial needle bearing 10, it is also adaptable to support the tappet roller 9 rotatably on the support shaft 7a directly or via a slide bearing.
  • the radial rolling bearing as in this embodiment, swing resistance of the pair of rocker arms 17, 17 about the rocker arm shaft 5 can be reduced and also the fuel consumption rate at the running of the engine can be reduced.
  • both the rocker arms 17, 17 are swung about the rocker arm shaft 5 as the cam 2 rotates, so as to reciprocate the two valve elements 12, 12 in an axial direction by pressing force exerted by both the projecting portions 18, 18 and spring force by the return spring 13 (which is omitted in Figs. 1 to 4 .
  • the return spring 13 which is omitted in Figs. 1 to 4 .
  • Figs. 30 , 34 Refer to Figs. 30 , 34 ).
  • the cam follower device of the embodiment when used, only by providing the single cam 2 and the single tappet roller 9, the two valve elements 12, 12 can be reciprocated simultaneously.
  • the number of parts in the valve train can be reduced. Consequently, the resulting valve train can be made smaller in size (space saving) and lighter in weight and can realize reductions in friction and production costs.
  • both the end portions of the support shaft 7a can be press fitted in the pair o support holes 8a, 8a without damaging the outer circumferential surface of the intermediate portion of the support shaft 7a.
  • a hardening treatment applied to the surface of the support shaft 7a an immersion quenching which is more inexpensive than induction hardening can be adopted. Consequently, the production costs can be suppressed.
  • both the rocker arms 17, 17 it is only required for both the rocker arms 17, 17 to be formed in the same shape and size, then, the positional relationship between both the rocker arms 17, 17 can be made proper, whereby the occurrence of a difference in contact state with their mating parts such as the valves can be prevented effectively.
  • rocker arms 17a to 17e which are shown in Figs. 5 to 9 can also be used as the pair of rocker arms.
  • These rocker arms 17a to 17e differ from the rocker arm 17 that has been described heretofore in shape of at least the other end portions (left end portions in Figs. 5 to 9 ) thereof.
  • a pair of holding pieces 19, 19 is projectingly provided on both front and rear sides (left- and right-hand sides in Fig. 5 ) of a projecting portion 18 provided on a lower surface of the other end portion thereof.
  • a pressing plate portion 21 having U-shaped cross section provided with a recessed portion 20 on a lower surface thereof is provided at the other end thereof, and a bottom surface of the recessed portion 20 is made into a pressing portion caused to strike a proximal end face of the valve element.
  • a flat plate portion 22 which is perpendicular to one end portion (a right end portion in Fig. 7 ) to an intermediate portion is provided at the other end portion, hole opening work is applied to a central portion of this flat plate portion 22 and then, burring process is applied to the portion to which the hole opening work is applied so as to form a cylindrical portion 23.
  • this cylindrical portion 23 is made into a through hole (or a screw hole) 24.
  • a distal end portion of an adjustment pin (or an adjustment screw), not shown, which is fittingly fixed in the through hole (or the screw hole) 24 is made into a pressing portion caused to strike the proximal end face of the valve element.
  • a cylindrical portion 25 is formed integrally at the other end portion by bending process.
  • An inside of the cylindrical portion 25 is made into a through hole (or a screw hole) 24 in which the aforesaid adjustment pin (or the adjustment screw), not shown, is fittingly fixed (or screw fixed).
  • burring process is applied to a peripheral portion of the through hole 4 so as to form a cylindrical portion 26.
  • a cylindrical member 27 is fixedly joined to the other end portion through welding, electric welding or the like. Then, an inside of the cylindrical member 27 is made into a through hole (or a screw hole) 24 in which the aforesaid adjustment pin (or the adjustment screw), not shown, is fittingly fixed (or screw fixed). Additionally, in order to secure an insertion length of the rocker arm shaft 5 (refer to Fig. 2 ) relative to a through hole 4 provided in an intermediate portion of the rocker arm 17e, a sleeve 28 is fittingly fixed in an inside of the through hole 4, so that the rocker arm shaft 5 is made to be inserted into an inside of the sleeve 28.
  • Figs. 10 to 11 show a second embodiment of the invention.
  • both the end portions are made into thick portions 31, 31.
  • internal surfaces of the other end portions of both the rocker arms 17h, 17h are caused to swell.
  • a thickness dimension T of the other end portions (the thick portions 31, 31) of both the rocker arms 17h, 17h is made larger than a thickness dimension t of one end portions and intermediate portions thereof (T>t).
  • Fig. 12 shows a third embodiment of the invention.
  • both the other end portions are made into thick portions 31a, 31a.
  • both side surfaces of the other end portions of both the rocker arms 17i, 17i are caused to swell.
  • the other configuration and function of this embodiment are similar to those of the second embodiment described above.
  • Fig. 13 shows a fourth embodiment of the invention.
  • an interval between a pair of valve elements 12, 12 which are to be pressed becomes remarkably large. Due to this, in this embodiment, an interval between a pair of rocker arms 17i, 17i is made remarkably large compared to the aforementioned respective embodiments so as to match the interval between both the valve elements 12, 12.
  • a tappet roller 9 disposed between one end portions (right end portions in Fig. 13 ) of both the rocker arms 17i, 17i, a tappet roller 9 is used which has the same axial dimension as those of the respective embodiments.
  • widths of gaps which reside between internal surfaces of the one end portions of both the rocker arms 17i, 17i and both axial end faces of the tappet roller 9 are both made far larger than a permissible axial displacement of the tappet roller 9.
  • the tappet roller 9 is displaced largely in the axial direction, whereby there emerges a possibility that a drawback is caused, such as a radial needle bearing 10 disposed radially inwards of the tappet roller 9 being dislocated outwards of the tappet roller 9 or the tappet roller 9 being disengaged from the cam 2, and hence, the construction is not preferred.
  • a drawback such as a radial needle bearing 10 disposed radially inwards of the tappet roller 9 being dislocated outwards of the tappet roller 9 or the tappet roller 9 being disengaged from the cam 2, and hence, the construction is not preferred.
  • the axial dimension of the tappet roller 9 is increased so as to match the interval between the internal surfaces of both the rocker arms 17i, 17i.
  • a drawback of increasing of the weight of the tappet roller 9 will be caused and it makes difficult for the engine to revolve at higher speeds or the fuel consumption rate at the time of running of the engine is increased, thus, such a construction is not preferred.
  • a ring spacer 32 and a cylindrical spacer 33 which are both fitted on a support shaft 7a are disposed in each of the gaps between the internal surfaces of the one end portions of both the rocker arms 17i, 17i and both the axial end faces of the tappet roller 9 in this order from the tappet roller 9 side while eliminating large looseness in the axial direction. Then, the axial displacement permitted to the tappet roller 9 (and the radial needle bearing 10) is controlled to a desired magnitude (a minute amount) by the respective ring spacers 32, 32 and the respective cylindrical spacers 33, 33.
  • the other configuration and function of this embodiment are similar to those of the third embodiment that has been described above.
  • Fig. 15 shows a fifth embodiment of the invention.
  • this embodiment in place of omitting the pair of cylindrical spacers 33, 33 (refer to Fig. 13 ), internal surfaces of one end portions (right end portions in Fig. 15 ) of a pair of rocker arms 17k, 17k are caused to swell into thick portions 34, 34.
  • an interval between the internal surfaces of the one end portions of both the rocker arms 17, 17 is narrowed, so that an axial displacement permitted to a tappet roller 9 is controlled to a desired magnitude (a minute amount).
  • the other configuration and function of this embodiment are similar to those of the fourth embodiment that has been described above except for the fact that no thick portion is provided at the other end portions (left end portions in Fig. 15 ) of both the rocker arms 17k, 17k.
  • Fig. 16 shows a sixth embodiment of the invention.
  • inclined plate portions 35, 35 are formed between one end portions (right end portions in Fig. 16 ) to intermediate portions and the other end portions (left end portions in Fig. 16 ) of a pair of rocker arms 17m, 17m so as to be inclined in directions in which the inclined plate portions 35, 35 approach each other as they extend towards the one end portions.
  • Figs. 17 to 18 show a seventh embodiment of the invention.
  • the sleeve 29 is fixed to both the rocker arms 17h, 17f so as to be extended therebetween.
  • male serrations (not shown) formed on outer circumferential surfaces of both end portions of the sleeve 29 into engagement with female serrations (not shown) formed on inner circumferential surfaces of both the through holes 4a, 4a, relative rotation at the press fitted portions is prevented effectively.
  • a rocker arm shaft 5 is inserted into an inside of thus formed sleeve 29.
  • lubricant is supplied between the inner circumferential surface of the sleeve 29 and the outer circumferential rocker arm shaft 5 from openings at the end portions of the sleeve 29 during the running of the engine, whereby frictional force acting between both the circumferential surfaces is reduced sufficiently.
  • the lubricant can be supplied to both the circumferential surface by this oil communication hole.
  • the aforesaid shapes of the other end portions of the rocker arms 17a to 17e, 17h, 17i which are shown in Figs. 5 to 12 can be adopted as the shape of the other end portions of the pair of rocker arms.
  • the other configuration and function are similar to those of the aforesaid first embodiment which is shown in Figs. 1 to 4 .
  • a radial needle bearing 36 is provided between an inner circumferential surface of a cylindrical sleeve 29 and an outer circumferential surface of a rocker arm shaft 5.
  • a pair of circular ring plates 37, 37 are fixedly joined to external surfaces of a pair of rocker arms 17f, 17f at peripheral portions of through holes 4a, 4a so that inner circumferential edges thereof are made to closely confront the outer circumferential surface of the rocker arm shaft 5.
  • the radial needle bearing 36 is prevented from being dislocated to an outside of the sleeve 29 through openings at both ends thereof by inner circumferential edge portions of both the circular ring plates 37, 37.
  • Figs. 20 to 22 show a ninth embodiment of the invention.
  • a tappet roller 9 is supported rotatably around a circumference of a support shaft 7a via a radial needle bearing 10 and is disposed in an interval portion defined between intermediate portions of a pair of plate-shaped rocker arms 17g, 17g. Therefore, in this embodiment, a pair of support holes 8a, 8a in which both end portions of the support shaft 7a are press fitted (brought into serrated engagement with) are formed concentric with each other at the intermediate portions of the pair of plate-shaped rocker arms 17g, 17g in positions aligned with each other.
  • spherically recessed portions 30, 30 are provided on lower surfaces of one end portions (right end portions in Figs. 20 to 21 ) of both the rocker arms 17g, 17g.
  • projecting portions 18, 18 which are similar to those in the aforesaid first to second embodiments are provided on lower surfaces of the other end portions (left end portions in Figs. 20 to 21 ) of both the rocker arms 17g, 17g.
  • both the rocker arms 17g, 17g are displaced in a swinging fashion about the abutment portion between the distal end faces of both the plungers 16, 16 and both the spherically recessed portions 30, 30 as centers (fulcrums) of their swing, so as to reciprocate the two valve elements 12, 12 in an axial direction by pressing force exerted by both the projecting portions 18, 18 and spring force by a return spring 13 (which is omitted in Figs. 20 to 22 . Refer to Figs. 30 , 34 .).
  • the cam follower device of this embodiment As has been described above, also when making up a valve train by the use of the cam follower device of this embodiment, only by providing the single cam 2 and the single tappet roller 9, the two valve elements 12, 12 can be made to reciprocate simultaneously.
  • the use of the cam follower device of this embodiment as a cam follower device to be built in the valve train can reduce the number of components involved in the valve train. Consequently, the resulting valve train can be made smaller in size (space saving) and lighter in weight and can realize reductions in friction and production costs.
  • both the end portions of the support shaft 7a can press fitted in the support holes 8a, 8a without damaging an outer circumferential surface of an intermediate portion of the support shaft 7a. Therefore, as a hardening treatment applied to the surface of the support shaft 7a, an immersion quenching which is more inexpensive than induction hardening can be adopted. Consequently, the production costs can be suppressed.
  • the aforesaid shapes of the other end portions of the rocker arms 17a to 17e, 17h, and 17i shown in Figs. 5 to 12 can be adopted as the shape of the other end portions of the pair of rocker arms.
  • various constructions can be adopted including a construction in which they are formed directly or via separate members at the one end portions of both the rocker arms.
  • a construction can also be adopted in which screw holes are provided at the one end portions of both the rocker arms and adjustment screws whose distal end portions are made into receiving portions are fixedly screwed into the screw holes, respectively.
  • Fig. 23 shows a tenth embodiment of the invention.
  • an interval between distal end faces of a pair of plungers 16, 16 which constitute fulcrums and an interval between proximal end faces of a pair of valve elements 12, 12 which are to be pressed become far larger than those of the ninth embodiment.
  • a tappet roller 9 which is disposed between intermediate portions of a pair of rocker arms 17n, 17n
  • a tappet roller 9 which has the same axial dimension as that of the tappet roller of the ninth embodiment. Therefore, in this embodiment, inclined plate portions 35a, 35b (non-parallel plate portions) are formed, respectively, between one end portions (right end portions in Fig.
  • an interval between internal surfaces of the intermediate portions of both the rocker arms 17n, 17n is narrowed, so as to control an axial displacement permitted to the tappet roller 9 to a desired magnitude (a minute amount).
  • a desired magnitude a minute amount.
  • the axial dimension of the tappet roller 9 is not necessary to be increased so as to match the interval between the distal end faces of both the plungers 16, 16 and the interval between the proximal end faces of both the valve elements 12, 12.
  • the other configuration and function are similar to those of the ninth embodiment.
  • FIGs. 25 to 27 show an eleventh embodiment of the invention.
  • a cam follower device of this embodiment is built in a valve train of an engine (of an OHC or DOHC type) such as, for example, a three-valve engine, a four-valve engine or a fifth-valve engine in which the number of at least one of inlet valves and exhaust valves provided per cylinder is made to be two or more.
  • the thus designed cam follower device of the embodiment includes a pair of plate-shaped rocker arms 17q, 17q which are identical to each other in shape and size, a single support shaft 7a and a single tappet roller 9.
  • the pair of plate-shaped rocker arms 17q, 17q are disposed parallel to each other with a predetermined interval (the same pitch as a pitch at which a pair of valve elements 12, 12 are disposed) and are joined together so as to prohibit a relative displacement therebetween by a connecting portion 38 provided in at least one location.
  • the support shaft 7a is fixed to one end portions (right end portions in Figs. 25 to 26 ) of both the rocker arms 17q, 17q so as to be extended therebetween. Because of this, a pair of support holes 8a, 8a is formed concentric with each other at the one end portions of both the rocker arms 17q, 17q in positions aligned with each other.
  • both end portions of the support shaft 7a are press fitted, respectively, in insides of both the support holes 8a, 8a through openings lying on sides thereof which oppose to each other.
  • angles at connecting portions between the rocker arms 17q, 17q and the connecting portion 38 are increased (to a magnitude which exceeds 90 degrees).
  • the relative swing of both the rocker arms 17q, 17q about the support shaft 7a is prevented by the connecting portion 38.
  • the tappet roller 9 is supported rotatably on an outer circumferential surface of an intermediate portion of the support shaft 7a via a radial needle bearing 10 (refer to Fig. 3 ).
  • a pair of through holes 4, 4 is formed concentric with each other at intermediate portions of the rocker arms 17q, 17q in positions aligned with each other.
  • a pair of projecting portions 18, 18 (pressing portions) is provided on lower surfaces of the other end portions (left end portions in Figs. 25 to 26 ) of the rocker arms 17q, 17q. Distal end faces of these projecting portions 18, 18 are each made into a partially cylindrical surface.
  • rocker arms 17q, 17q are fabricated in the following manner. Firstly, as shown in Fig. 27A , by applying stamping process to a single sheet metal, a pair of plate-shaped rocker arms 17q, 17q which are identical to each other in shape and size are formed so that the pair of plate-shaped rocker arms 17q, 17q are made integral by a connecting portion 38 provided in at least one location. Thereafter, as shown in Fig.
  • both end portions of the connecting portion 38 are each bent through 90 degrees until the pair of rocker arms become parallel to each other, whereby the pair of plate-shaped rocker arms 17q, 17q are formed which are disposed parallel to each other with a predetermined interval provided therebetween and are connected together by the connecting portion 38 which is provided in at least one location so that relative displacement between the rocker arms 17q, 17q are disabled.
  • both the end portions of the support shaft 7a having the tappet roller 9 provided around the circumference of the intermediate portion thereof can also be fitted in the support holes 8a, 8a, respectively.
  • a rocker shaft 5 as a stationary shaft is inserted in the respective through holes 4, 4 without looseness and interference therebetween, whereby the swing displacement of the rocker arms 17q, 17q about the rocker arm shaft 5 is enabled.
  • an outer circumferential surface of the tappet roller 9 is brought into abutment with an outer circumferential surface of a cam 2 which is fixedly provided on a camshaft 1, and the distal end faces of the projecting portions 18, 18 are caused to strike individually proximal end faces of the two valve elements 12, 12 (the two inlet valves or the two exhaust valves provided for the same cylinder).
  • the two valve elements 12, 12 can be reciprocated simultaneously. Therefore, compared with the case where only the conventional cam follower devices are built in the valve train (the independent cam follower device is built in each valve element), the number of components in the valve train can be reduced. Consequently, the resulting valve train can be made smaller in size (space saving) and lighter in weight and can realize reductions in friction and production costs.
  • the end portions of the support shaft 7a can be press fitted, respectively, in the pair of support holes 8a, 8a without damaging the outer circumferential surface of the intermediate portion of the support shaft 7a.
  • an immersion quenching which can be implemented inexpensive relative to induction hardening, can be adopted as a hardening treatment applied to the surface of the support shaft 7a. Consequently, the production costs can be suppressed.
  • the support shaft 7a by forming the support shaft 7a into a circular tubular shape and providing an oil supply hole at an axially intermediate portion thereof, it also becomes possible to supply oil to the radial needle bearing 10.
  • rocker arm shaft 5 by forming the rocker arm shaft 5 into a circular tubular shape and providing oil holes at an axially intermediate portion of the rocker arm shaft 5 in positions lying in insides of the through holes 4, 4, a slide contact portion between inner circumferential surfaces of the through holes 4, 4 and the outer circumferential surface of the rocker arm shaft 5 can be lubricated.
  • Figs. 28 to 29 show a twelfth embodiment of the invention.
  • cylindrical portions 39, 39 are formed by burring process which is applied to peripheral portions of through holes 4b, 4b provided at intermediate portions of a pair of rocker arms 17r, 17r, which are disposed parallel to each other with a predetermined interval and are connected by a connecting portion 38 in at least one location so as to disable relative displacement.
  • These cylindrical portions 39, 39 secure an insertion length of a rocker arm shaft 5 (refer to Fig. 26 ) into the respective through holes 4b, 4b and suppress wear at the swing support portions. Since the configuration and function of other portions are like to those of the cam follower device illustrated in the eleventh embodiment, the description of like portions will be omitted herein.
  • the connecting portion which connects integrally the pair of rocker arms to each other can be formed on the edges of the rocker arms in positions which cause no problem when being built in the cam follower device, when the cam follower device is assembled on to the engine and when the cam follower device is incorporated in the engine.
  • the position where the connecting portion is formed is desirably as close to the through hole into which the rocker arm shaft is inserted as possible. This is because the inertia moment around the rocker arm shaft can be suppressed to a smaller level as the connecting portion forming position comes closer to the through hole.
  • the construction (the single-roller type) is adopted in which the single tappet roller is disposed round the support shaft.
  • a construction (a double-roller type) can also be adopted in which two outside diameter side and inside diameter side tappet rollers which are combined concentrically and relatively rotatably are disposed around the circumference of the support shaft.
  • the construction of the invention can also be applied to a screw type adjuster system, an HLA system in which the cam follower device of the invention is combined with lash adjusters and the like.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Valve-Gear Or Valve Arrangements (AREA)
EP07740682A 2006-03-31 2007-03-30 Dispositif de poussoir de soupape Withdrawn EP2003295A2 (fr)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
JP2006096399 2006-03-31
JP2006238741A JP2008057514A (ja) 2006-09-04 2006-09-04 カムフォロア装置
JP2006282123A JP2007292042A (ja) 2006-03-31 2006-10-17 カムフォロア装置
PCT/JP2007/057246 WO2007114381A1 (fr) 2006-03-31 2007-03-30 Dispositif de poussoir de soupape

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EP2003295A2 true EP2003295A2 (fr) 2008-12-17

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EP (1) EP2003295A2 (fr)
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US9179796B2 (en) * 2010-09-22 2015-11-10 Cornelia Bean Ltd. Beverage making container for placement onto a cup
DE102011012614A1 (de) 2011-02-28 2012-08-30 Neumayer Tekfor Holding Gmbh Nockenfolger und Ventiltrieb

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Publication number Priority date Publication date Assignee Title
US4614171A (en) * 1985-07-05 1986-09-30 W H Industries Inc. Rocker arm construction
JPH09217751A (ja) * 1996-02-09 1997-08-19 Nippon Seiko Kk 軸受装置
JP3535431B2 (ja) * 1999-12-28 2004-06-07 本田技研工業株式会社 内燃機関の動弁装置
JP2003206708A (ja) * 2002-01-16 2003-07-25 Ntn Corp ローラ付きカムフォロア
JP4110882B2 (ja) * 2002-08-22 2008-07-02 トヨタ自動車株式会社 ロッカーアーム
JP2004100499A (ja) 2002-09-06 2004-04-02 Nsk Ltd カムフォロア装置
JP3905454B2 (ja) * 2002-10-11 2007-04-18 株式会社ジェイテクト ロッカアーム
JP4318969B2 (ja) * 2003-06-17 2009-08-26 本田技研工業株式会社 内燃機関の動弁装置
JP2006096399A (ja) 2004-09-30 2006-04-13 Lion Corp 段ボール箱
JP2006238741A (ja) 2005-03-01 2006-09-14 Nagasaki Univ 流れ藻捕集装置と藻場の生成方法
JP2006282123A (ja) 2005-04-05 2006-10-19 Toyota Motor Corp 太陽電池出力により空調出力が制御される車輌

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US20090173300A1 (en) 2009-07-09

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