EP0490426A1 - Valve lifter - Google Patents
Valve lifter Download PDFInfo
- Publication number
- EP0490426A1 EP0490426A1 EP91203144A EP91203144A EP0490426A1 EP 0490426 A1 EP0490426 A1 EP 0490426A1 EP 91203144 A EP91203144 A EP 91203144A EP 91203144 A EP91203144 A EP 91203144A EP 0490426 A1 EP0490426 A1 EP 0490426A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- valve lifter
- lifter
- depending
- valve
- cam lobe
- 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.)
- Granted
Links
Images
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
- F01L1/267—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 with means for varying the timing or the lift of the valves
-
- 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
- F01L1/245—Hydraulic tappets
- F01L1/25—Hydraulic tappets between cam and valve stem
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- 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
- F01L13/00—Modifications of valve-gear to facilitate reversing, braking, starting, changing compression ratio, or other specific operations
- F01L13/0015—Modifications of valve-gear to facilitate reversing, braking, starting, changing compression ratio, or other specific operations for optimising engine performances by modifying valve lift according to various working parameters, e.g. rotational speed, load, torque
- F01L13/0036—Modifications of valve-gear to facilitate reversing, braking, starting, changing compression ratio, or other specific operations for optimising engine performances by modifying valve lift according to various working parameters, e.g. rotational speed, load, torque the valves being driven by two or more cams with different shape, size or timing or a single cam profiled in axial and radial direction
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
- F02B2275/00—Other engines, components or details, not provided for in other groups of this subclass
- F02B2275/18—DOHC [Double overhead camshaft]
Abstract
Description
- This invention relates to valve lifters (also called tappets or cam followers) for use in engines having valve actuation. In preferred embodiments, the invention relates to so-called direct acting valve lifters.
- Increased efficiency in modern engines has resulted from valve train mass reduction, (for lower friction losses and/or higher engine speeds), and from increasing the number of valves per cylinder. Direct acting valve arrangements, as in overhead cam engines are of particular interest since they can limit the reciprocating elements to the valves and their associated valve lifters.
- Design efforts to reduce lifter mass have involved the use of ceramics, metal matrix composites and magnesium, as well as other materials. However, the cost of such materials, the special processing and the extensive development and testing required to use them can cause these designs to be prohibitive in terms of cost.
- The present invention seeks to provide an improved valve lifter.
- According to an aspect of the present invention, there is provided a valve lifter as specified in claim 1.
- The term "oblong" used herein is intended to cover any suitable shape having its chief axis longer than its transverse diameter.
- This invention can provide means to minimize valve lifter mass through changes in geometry not requiring special materials.
- The valve lifter preferably has a cam lobe contact surface that is approximately the width of or slightly wider than the width of an associated cam lobe. The contact surface may be extended longitudinally (usually in the direction of the cam sliding motion) as desired to allow high velocity cam profiles to be used without requiring an increase in the width of the contact surface or the lifter. Semi-cylindrical end walls or skirts may depend from the longitudinal ends of the cam lobe contact surface to guide and stabilize the lifter in the lifter gallery. The walls may be ribbed for strength.
- A circular recess in a mechanical version of the lifter is adapted to receive a valve shim. In a hydraulic version of the lifter, a cylindrical depending wall between the semi-cylindrical skirts defines a cylinder to receive a hydraulic lash adjuster.
- In preferred embodiments, low mass and adequate strength characteristics can be provided by the use of thin walls and reinforcing ribs preferably formed by investment casting.
- The ends of the cam lobe contacting surface and the depending walls are preferably semi-circular, and they may also be of any other suitable part-circular shape.
- According to another aspect of the present invention, there is provided apparatus for operating a valve in an internal combustion engine as specified in claim 12.
- An embodiment of the present invention is described below, by way of illustration only, with reference to the accompanying drawings, in which:
- Figure 1 is a cross-sectional view of part of an engine cylinder head illustrating an embodiment of hydraulic valve lifter and associated cam;
- Figure 2 is a bottom plan view of the hydraulic lifter taken along line 2-2 of Figure 1;
- Figure 3 is a top plan view of part of a lifter gallery showing the surface of several hydraulic lifters, taken along the line 3-3 of Figure 1;
- Figure 4 is a cross-sectional view of the hydraulic lifter of Figure 1 taken along the line of 4-4 of Figure 2;
- Figure 5 is a perspective view of the hydraulic lifter of Figure 1;
- Figure 6 is a partial cross-sectional view of a cylinder head and mechanical lifter;
- Figure 7 is a longitudinal cross-sectional view of the mechanical lifter of Figure 6 taken along line 7-7 of Figure 8;
- Figure 8 is a bottom plan view of the mechanical lifter of Figure 6; and
- Figure 9 is a view corresponding to Figure 3 of an alternative form of hydraulic lifter.
- Referring to Figures 1 to 5, an
engine 10 with a lifter and cam gallery 12 comprises acamshaft 13 and a plurality ofhydraulic valve lifters 14 operated by the camshaft through a plurality ofcams 16 havinglobes 18. - The
lifter gallery 20 andcam cover 22 of the lifter and cam gallery 12 may be made of aluminium, cast iron or other suitable material; while thecamshaft 13 andhydraulic lifters 14 are preferably made of alloy steel, although other materials may be used. - Each
hydraulic lifter 14 includes afollower body 23 carrying a conventional hydraulic element assembly orlash adjuster 24 which receives a supply of hydraulic fluid viapassages 34 from apassage 36 in one wall of the lifter gallery. The cam-engaging top 38 of thefollower body 23 is oblong with semi-circular ends and generally parallel connecting sides. Semi-circularcylindrical end walls 40 depend from the semi-circular ends. Thewalls 40 are optionally reduced in circumference at theirbottom portions 42 to reduce the mass of the lifters. Descendingribs 44 containing thehydraulic passages 34 connect thecylindrical walls 40 with the underside of the cam-engaging top 38. - A substantially circular cylindrical depending
wall 50 extends from the centre of thefollower body 23 to provide a closed-end cylinder for receiving thehydraulic lash adjuster 24. Thiswall 50, as shown, is slightly wider than thetop 38 of thefollower body 23 and has tapered upper edges 52 (best seen in Figure 5). - The lash adjuster or
hydraulic element assembly 24 includes a cup-shaped piston 54 which in use engages the top of avalve stem 56. Thevalve stem 56 is in use urged upwardly (that is, towards the lash adjuster 24) by acompression spring 57 which engages awasher 58 retained on the valve stem bysplit keepers 59 in the usual manner. If desired a smaller circular cylindrical lash adjuster or even a narrow oblong adjuster could be provided in place of theadjuster 24 so that the width of the cylinder formed by thewall 50 could be made so as to be no greater than the width of thetop 38. - Also, as may be seen in Figure 9, the
tapered edges 52 may be omitted, providing lifter 14' with an outwardly bulging oblong flat top 38'. - Turning now to Figures 6, 7 and 8, a
mechanical lifter 60 is shown which shares some of the features of thehydraulic lifter 14.Lifter 60 comprises afollower body 61 reciprocably actuated in a lifter guide (not shown) by alobe 62 of acamshaft 64. Thebody 61 is engaged at its bottom by anend 80 of avalve stem 65 which is urged upwardly (that is, towards the follower body 61) by acompression spring 66 retained between awasher 68 held bykeepers 70 and acylinder head wall 72. Theupper end 80 of thevalve stem 65 carries a lash cap acting as ashim 84 that is received in a recess in the bottom of thefollower body 61. Other types of shims could also be used. - Semi-cylindrical depending
walls 86 at the ends of thefollower body 61 reduce in circumference at 88. Reinforcingribs 90 provide increased rigidity of thebody 61. - It should be understood that in some cases it might be desirable to extend the semi-cylindrical walls downwardly and eliminate the reduction in circumference. This would, of course, increase the mass of the lifter.
- Oblong
openings 92 in the lifter gallery 20 (Figure 3) or 20' (Figure 9), are provided to receive reciprocably thelifters - The
openings 92 preferably include smallsemi-circular ends 94 which are engaged by theend walls 40 of thelifters 14, 14' (orwalls 86 of mechanical lifters 60) to carry both the lateral and longitudinal side forces imposed on the lifters in operation. - The ends 94 (Figure 9) are connected by
arcs 96 of a larger centre circle. Thearcs 96 are spaced with clearance outwardly from the sides of thevalve lifters 14, 14' so that all bearing loads are carried by thesemi-cylindrical end walls 40. This provides good control of lifter motion and minimizes manufacturing tolerance problems since only theends 94 of the openings are required to be closely dimensioned. - The enlarged portions shown as
arcs 96 could be formed of any other suitable configuration or could be omitted from the lifter carrier structure if desired. - Other aspects of the invention are covered in our co-pending Japanese patent application no. (RJ/3583), the contents of which is incorporated herein by reference.
Claims (14)
- A valve lifter comprising an oblong cam lobe contacting surface (38,80) which includes longitudinally spaced ends; and a wall (40,86) depending from each end of the cam lobe contacting surface.
- A valve lifter according to claim 1, wherein the ends of the cam lobe contacting surface are substantially semi-circular.
- A valve lifter according to claim 1 or 2, wherein each end wall is substantially semi-cylindrical and semi-circular.
- A valve lifter according to claim 3, wherein a portion of each depending wall is of a reduced circumference.
- A valve lifter according to any preceding claim, comprising one or more ribs (44,90) depending from the cam lobe contacting surface and connected to the depending walls.
- A valve lifter according to claim 5, wherein the rib or ribs comprise passages therein for receiving hydraulic fluid.
- A valve lifter according to any preceding claim, comprising a substantially cylindrical member (50) depending from the cam lobe contacting surface and adapted to receive a hydraulic lash adjuster (24).
- A valve lifter according to claim 7, comprising two or more ribs (44) depending from the cam lobe contacting surface and connecting the cylindrical member to the depending walls.
- A valve lifter according to any preceding claim, wherein the depending walls are adapted to carry both longitudinal and lateral side loads applied to the lifter.
- A valve lifter according to any preceding claim, wherein the depending walls are formed by investment casting of an alloy steel.
- A valve lifter according to any preceding claim, wherein the lifter is made by casting of an alloy.
- Apparatus for operating a valve in an internal combustion engine comprising a lifter carrier (20,20') including an opening (92) with spaced semi-cylindrical end portions (94), and a valve lifter (14,61) slidably received in the opening and including an oblong cam engaging portion (23,61) which comprises spaced longitudinal ends each connected to a depending semi-cylindrical end wall (40,86), the end walls engaging the end portions of the opening so as to carry both longitudinal and lateral side loads applied to the lifter.
- Apparatus according to claim 12, comprising a camshaft including at least one cam lobe (18,62) adapted to contact the cam engaging portion of the valve lifter in a sliding manner.
- Apparatus according to claim 13, wherein the ends of the cam engaging portion of the lifter lie along a line substantially parallel to the motion of its associated cam lobe.
Applications Claiming Priority (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US628694 | 1990-12-14 | ||
US07/628,694 US5090364A (en) | 1990-12-14 | 1990-12-14 | Two-step valve operating mechanism |
US07/678,402 US5070827A (en) | 1991-04-01 | 1991-04-01 | Low mass valve lifters |
US678402 | 1991-04-01 |
Publications (2)
Publication Number | Publication Date |
---|---|
EP0490426A1 true EP0490426A1 (en) | 1992-06-17 |
EP0490426B1 EP0490426B1 (en) | 1994-08-24 |
Family
ID=27090771
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP19910203144 Expired - Lifetime EP0490426B1 (en) | 1990-12-14 | 1991-12-02 | Valve lifter |
Country Status (4)
Country | Link |
---|---|
EP (1) | EP0490426B1 (en) |
JP (1) | JP2547495B2 (en) |
CA (1) | CA2054877C (en) |
DE (1) | DE69103613T2 (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP1600609A3 (en) * | 2004-05-25 | 2008-10-15 | Schaeffler KG | Valve lifter for an internal combustion engine |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP6295721B2 (en) * | 2014-02-28 | 2018-03-20 | 三菱自動車工業株式会社 | Engine valve structure |
Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0108238A1 (en) * | 1982-10-12 | 1984-05-16 | FIAT AUTO S.p.A. | Tappet for internal combustion engines with variable profile camshafts |
US4637357A (en) * | 1985-04-29 | 1987-01-20 | Yamaha Hatsudoki Kabushiki Kaisha | Tappet arrangement for engine valve train |
EP0267631A1 (en) * | 1983-12-07 | 1988-05-18 | Eaton Corporation | Self-contained hydraulic bucket lifter |
DE3806839A1 (en) * | 1988-03-03 | 1989-09-14 | Bayerische Motoren Werke Ag | Positionally secured valve tappet, especially for internal combustion engines |
Family Cites Families (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2863432A (en) | 1957-07-18 | 1958-12-09 | Curtiss Wright Corp | Valve tappet mechanism |
JPS62154210U (en) * | 1986-03-22 | 1987-09-30 |
-
1991
- 1991-11-04 CA CA 2054877 patent/CA2054877C/en not_active Expired - Fee Related
- 1991-12-02 DE DE1991603613 patent/DE69103613T2/en not_active Expired - Fee Related
- 1991-12-02 EP EP19910203144 patent/EP0490426B1/en not_active Expired - Lifetime
- 1991-12-16 JP JP3332169A patent/JP2547495B2/en not_active Expired - Lifetime
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0108238A1 (en) * | 1982-10-12 | 1984-05-16 | FIAT AUTO S.p.A. | Tappet for internal combustion engines with variable profile camshafts |
EP0267631A1 (en) * | 1983-12-07 | 1988-05-18 | Eaton Corporation | Self-contained hydraulic bucket lifter |
US4637357A (en) * | 1985-04-29 | 1987-01-20 | Yamaha Hatsudoki Kabushiki Kaisha | Tappet arrangement for engine valve train |
DE3806839A1 (en) * | 1988-03-03 | 1989-09-14 | Bayerische Motoren Werke Ag | Positionally secured valve tappet, especially for internal combustion engines |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP1600609A3 (en) * | 2004-05-25 | 2008-10-15 | Schaeffler KG | Valve lifter for an internal combustion engine |
Also Published As
Publication number | Publication date |
---|---|
DE69103613D1 (en) | 1994-09-29 |
EP0490426B1 (en) | 1994-08-24 |
CA2054877A1 (en) | 1992-06-15 |
JP2547495B2 (en) | 1996-10-23 |
CA2054877C (en) | 1994-06-14 |
DE69103613T2 (en) | 1994-12-22 |
JPH04276103A (en) | 1992-10-01 |
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