EP0396288A1 - Hydraulic tappet - Google Patents
Hydraulic tappet Download PDFInfo
- Publication number
- EP0396288A1 EP0396288A1 EP90304248A EP90304248A EP0396288A1 EP 0396288 A1 EP0396288 A1 EP 0396288A1 EP 90304248 A EP90304248 A EP 90304248A EP 90304248 A EP90304248 A EP 90304248A EP 0396288 A1 EP0396288 A1 EP 0396288A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- reservoir
- collar
- tappet
- annular
- duct
- 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
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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
- F01L1/20—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
Definitions
- the present invention refers to an internal combustion engine having a hydraulic tappet able to prevent any air bubbles which may be present in oil arriving from a lubricating circuit and made to circulate in an outer reservoir, from reaching an inner reservoir and possibly the high pressure chamber, since gases tend to exert an unsteadying or prejudicial effect on the supply of oil to the inner reservoir and thence to the high pressure chamber, and therefore also on the compensation of play in the tappet, particularly when the internal combustion engine is restarted after a period of rest.
- Hydraulic tappets basically comprise a first element, or outer part engaging a driving cam, an outer reservoir where the oil is first collected, and a second element, or inner part, telescopically moving inside the first element and in contact with the stem of one of the valves of the internal combustion engine.
- An inner reservoir and a high pressure chamber of variable capacity are formed by the telescopic sliding of the second element within the first element, such high pressure chamber communicating with the inner reservoir by means of a check or ball-valve.
- the invention is conceived for generally overhead cam drives, where bubbles tend to rise to the parts in the region driven by the cam.
- the present invention in a first embodiment, features an inclined duct extending from the outside of the inner wall of the outer reservoir towards the inside, and also extending in an upwards direction to a higher point in the inner reservoir, obtained by mechanical working on the known inner annular collar provided in the outer part to separate the outer reservoir from the inner reservoir.
- the duct provided in the collar which is positioned between the labyrinth and the receiving seat for the inner reservoir is obtained by making suitable grooves and rebates, for instance by milling, in said inner collar.
- an L-shaped channel being a closed portion in the form of a right-angle in co-operation with an insert able to close the bottom of the reservoir as in the first embodiment of the invention, wherein a vertical cylindrical element of the insert fits into the receiving cavity for the telescopically moving inner part and thus can form a vertical guiding wall for the inner part which slides inside the outer one.
- the vertical cylindrical element thus performs two important functions.
- a hydraulic tappet comprising an inner part and an outer part. Between these parts there are defined an outer reservoir, an inner reservoir and a high pressure chamber, respectively.
- the oil from the lubrication circuit enters the outer reservoir via an inlet and then moves into the inner reservoir flowing through suitable openings. Subsequently, the oil moves into the high pressure chamber as the result of the relative movement of the telescopically moving parts.
- the oil flowing from the lubrication circuit to the outer reservoir tends to contain air bubbles which would prejudice the compensating function of the tappet if the bubbles flowed into the inner reservoir and thence into the high pressure chamber.
- the oil in the outer reservoir is transferred to the inner one via a duct which preferably draws it directly from the bottom of the outer reservoir. Since any air bubbles in the oil tend to rise upwards in the outer reservoir, the duct inlet will contain reduced or no air contact.
- this concept has been difficult to put into practice, and the present invention aims to practise it in an easy and economical way.
- the outer part 10 of the hydraulic tappet consists of a monoblock provided with an inwardly and upwardly extending inlet duct 12 through which the oil from the lubrication circuit of the internal combustion engine enters.
- the oil then arrives in the upper region of an outer reservoir 14 and flows through a minimum of 180° along a circular path 16 formed between an outer wall 18 and an inner collar 20 which are integral with the outer part monobloc, and reaches a position on the right hand side as viewed, which side is indicated at 22 in Figs 1 and 2.
- the collar 20 provides an abutment 24, which is drilled or other mechanically worked to obtain an upwardly and inwardly inclined duct 26.
- the bottom of the outer annular reservoir comprises an insert 28 consisting of an annular diaphragm which is not present for the working, being mounted only after the inclined duct 26 has been formed. Therefore, before positioning insert 28, it has been made possible for the tip of a drill to be inserted from below in the appropriately inclined direction of the axis 30 of duct 26, in order to enable production of such duct by boring or drilling in an easy and economical way.
- the inlet of duct 26 is in the lower part of the outer chamber portion 22 and the outlet of duct 26 is located in the upper part of a cavity 32 destined to receive the parts intended to form the inner reservoir and the high pressure chamber and intended also to engage the valve stem in a manner compensated for lost motion.
- duct 26 enables oil to be drawn in with minimum or zero air bubbles even after long standing before a start-up of the engine.
- the bottom of the outer reservoir is closed by insert of said annular diaphragm 28, which is made in any suitable material.
- the inner cylindrical surfaces 36 and 34 of collar 20 define respectively a receiving cavity and a guide for the known telescopically moving parts (not shown) of the hydraulic tappet which form the inner reservoir and the high pressure chamber in known manner.
- the function of oil conveying duct 26 of the first embodiment is provided by formation by mechanical working for example by milling, of a vertical groove 38 in the wall of a collar 20 likewise formed as a monobloc with outer part 20 and outer wall 18 and inlet channel 12, said collar 20 generally dividing outer and inner reservoirs 14 and 32.
- the collar 20 separates an outer reservoir labyrinth 22 from a cavity which receives the telescoping part forming the abutment with the valve stem, the inner reservoir and the high pressure chamber.
- a radial groove 40 is provided e.g. milled in the lower edge of the collar 20.
- the grooves 38 and 40 generally perpendicular to each other, together with a preferably metal insert 42 which consists of an upper and axially extending cylindrical sleeve 44 and an annular and radially extending lower flange 46, form a duct, which has a closed portion in the general form of a right- angle, i.e. shaped as a "L", which duct communicates with and draws oil from the bottom of the outer reservoir.
- the external periphery of the flange 46 is suitably secured to the internal vertical surface 48 of the outer wall 18 of the outer part 10, whereas the external surface of the sleeve 44 fits snugly into the internal bore or cavity formed on the internal surface of collar 20. Therefore, the inner surface of sleeve 44 acts as a guide for the usual telescopically moving parts of the hydraulic tappet.
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Valve-Gear Or Valve Arrangements (AREA)
Abstract
Description
- The present invention refers to an internal combustion engine having a hydraulic tappet able to prevent any air bubbles which may be present in oil arriving from a lubricating circuit and made to circulate in an outer reservoir, from reaching an inner reservoir and possibly the high pressure chamber, since gases tend to exert an unsteadying or prejudicial effect on the supply of oil to the inner reservoir and thence to the high pressure chamber, and therefore also on the compensation of play in the tappet, particularly when the internal combustion engine is restarted after a period of rest.
- Hydraulic tappets basically comprise a first element, or outer part engaging a driving cam, an outer reservoir where the oil is first collected, and a second element, or inner part, telescopically moving inside the first element and in contact with the stem of one of the valves of the internal combustion engine. An inner reservoir and a high pressure chamber of variable capacity are formed by the telescopic sliding of the second element within the first element, such high pressure chamber communicating with the inner reservoir by means of a check or ball-valve. The invention is conceived for generally overhead cam drives, where bubbles tend to rise to the parts in the region driven by the cam.
- One of the drawbacks of this type of tappet is the fact that the oil reaching first the outer reservoir and then the inner reservoir and the high pressure chamber may contain air bubbles so that there is less oil than needed in the high pressure chamber especially when the engine is restarted and therefore play of the tappet cannot be fully adjusted.
- In order to minimise the drawback of gas, e.g. air bubbles in the oil reaching the high pressure chamber, provision is made in prior proposals for a duct drawing in oil from the bottom of the outer reservoir where there is minimum or no air since air tends to rise. Such a duct is usually complicated and costly to make, but the invention aims at improving this kind of duct. In order to overcome these drawbacks, the present invention, in a first embodiment, features an inclined duct extending from the outside of the inner wall of the outer reservoir towards the inside, and also extending in an upwards direction to a higher point in the inner reservoir, obtained by mechanical working on the known inner annular collar provided in the outer part to separate the outer reservoir from the inner reservoir. This can be obtained by boring a hole in an element projecting from the collar, e.g. using a drill which is introduced from the bottom of the outer part, such introduction being enabled by the fact that the channel forming the outer labyrinth-shaped reservoir is open at the bottom for the mechanical working and is only closed later, after such duct has been made, by addition of an annular base.
- According to another embodiment of the present invention, the duct provided in the collar which is positioned between the labyrinth and the receiving seat for the inner reservoir is obtained by making suitable grooves and rebates, for instance by milling, in said inner collar. There is thus provided an L-shaped channel, being a closed portion in the form of a right-angle in co-operation with an insert able to close the bottom of the reservoir as in the first embodiment of the invention, wherein a vertical cylindrical element of the insert fits into the receiving cavity for the telescopically moving inner part and thus can form a vertical guiding wall for the inner part which slides inside the outer one. The vertical cylindrical element thus performs two important functions.
- The present invention will now be described in detail with reference to the attached drawings wherein:
- Figs 1 and 2 show respectively a vertical cross-section and an underneath plan view of the outer part of the tappet, according to a first embodiment of the invention; and
- Figs 3 and 4 show a vertical cross-section and an underneath plan view of a second embodiment of the invention.
- There is known a hydraulic tappet comprising an inner part and an outer part. Between these parts there are defined an outer reservoir, an inner reservoir and a high pressure chamber, respectively. The oil from the lubrication circuit enters the outer reservoir via an inlet and then moves into the inner reservoir flowing through suitable openings. Subsequently, the oil moves into the high pressure chamber as the result of the relative movement of the telescopically moving parts.
- The oil flowing from the lubrication circuit to the outer reservoir tends to contain air bubbles which would prejudice the compensating function of the tappet if the bubbles flowed into the inner reservoir and thence into the high pressure chamber. In order to avoid this drawback, the oil in the outer reservoir is transferred to the inner one via a duct which preferably draws it directly from the bottom of the outer reservoir. Since any air bubbles in the oil tend to rise upwards in the outer reservoir, the duct inlet will contain reduced or no air contact. However, this concept has been difficult to put into practice, and the present invention aims to practise it in an easy and economical way.
- According to one form of embodiment of the invention (Figs 1 and 2), the
outer part 10 of the hydraulic tappet consists of a monoblock provided with an inwardly and upwardly extendinginlet duct 12 through which the oil from the lubrication circuit of the internal combustion engine enters. The oil then arrives in the upper region of anouter reservoir 14 and flows through a minimum of 180° along acircular path 16 formed between anouter wall 18 and aninner collar 20 which are integral with the outer part monobloc, and reaches a position on the right hand side as viewed, which side is indicated at 22 in Figs 1 and 2. In a position opposite that of theoil inlet duct 12, thecollar 20 provides anabutment 24, which is drilled or other mechanically worked to obtain an upwardly and inwardly inclined duct 26. This working is made possible by the fact that the bottom of the outer annular reservoir comprises aninsert 28 consisting of an annular diaphragm which is not present for the working, being mounted only after the inclined duct 26 has been formed. Therefore, before positioning insert 28, it has been made possible for the tip of a drill to be inserted from below in the appropriately inclined direction of theaxis 30 of duct 26, in order to enable production of such duct by boring or drilling in an easy and economical way. As shown in Fig 1, the inlet of duct 26 is in the lower part of theouter chamber portion 22 and the outlet of duct 26 is located in the upper part of acavity 32 destined to receive the parts intended to form the inner reservoir and the high pressure chamber and intended also to engage the valve stem in a manner compensated for lost motion. By this means, duct 26 enables oil to be drawn in with minimum or zero air bubbles even after long standing before a start-up of the engine. After the inclined duct 26 has been formed, the bottom of the outer reservoir is closed by insert of saidannular diaphragm 28, which is made in any suitable material. The innercylindrical surfaces 36 and 34 ofcollar 20 define respectively a receiving cavity and a guide for the known telescopically moving parts (not shown) of the hydraulic tappet which form the inner reservoir and the high pressure chamber in known manner. - According to the second embodiment of the invention (Figs 3 and 4) which aims also to achieve the same result, e.g. reduce (air) bubbles reaching the inner reservoir, the function of oil conveying duct 26 of the first embodiment is provided by formation by mechanical working for example by milling, of a
vertical groove 38 in the wall of acollar 20 likewise formed as a monobloc withouter part 20 andouter wall 18 andinlet channel 12, saidcollar 20 generally dividing outer andinner reservoirs collar 20 separates anouter reservoir labyrinth 22 from a cavity which receives the telescoping part forming the abutment with the valve stem, the inner reservoir and the high pressure chamber. Aradial groove 40 is provided e.g. milled in the lower edge of thecollar 20. Thegrooves metal insert 42 which consists of an upper and axially extendingcylindrical sleeve 44 and an annular and radially extendinglower flange 46, form a duct, which has a closed portion in the general form of a right- angle, i.e. shaped as a "L", which duct communicates with and draws oil from the bottom of the outer reservoir. The external periphery of theflange 46 is suitably secured to the internalvertical surface 48 of theouter wall 18 of theouter part 10, whereas the external surface of thesleeve 44 fits snugly into the internal bore or cavity formed on the internal surface ofcollar 20. Therefore, the inner surface ofsleeve 44 acts as a guide for the usual telescopically moving parts of the hydraulic tappet.
Claims (3)
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
IT2021489 | 1989-04-20 | ||
IT8920214A IT1230012B (en) | 1989-04-20 | 1989-04-20 | HYDRAULIC TAPPET WITH OIL SUCTION DUCT, FROM THE EXTERNAL TANK TO THE INTERNAL TANK WITHOUT INCLUSIONS OF AIR BUBBLES, MADE BY MECHANICAL PROCESSING. |
Publications (2)
Publication Number | Publication Date |
---|---|
EP0396288A1 true EP0396288A1 (en) | 1990-11-07 |
EP0396288B1 EP0396288B1 (en) | 1993-06-16 |
Family
ID=11164816
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP90304248A Expired - Lifetime EP0396288B1 (en) | 1989-04-20 | 1990-04-20 | Hydraulic tappet |
Country Status (3)
Country | Link |
---|---|
EP (1) | EP0396288B1 (en) |
DE (1) | DE69001952T2 (en) |
IT (1) | IT1230012B (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0443146A1 (en) * | 1990-02-20 | 1991-08-28 | Bayerische Motoren Werke Aktiengesellschaft | Tappet with hydraulic valve lash adjuster |
EP0566526A1 (en) * | 1992-04-14 | 1993-10-20 | Alusuisse-Lonza Services Ag | Hydraulic valve tappet cup-like housing for internal combustion engines with overhead camshaft |
US5267538A (en) * | 1991-06-07 | 1993-12-07 | Ina Walzlager Schaeffler Kg | Mechanical valve tappet for an internal combustion engine |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0224666A1 (en) * | 1985-11-29 | 1987-06-10 | INA Wälzlager Schaeffler KG | Self adjusting hydraulic valve tappet |
DE3805002A1 (en) * | 1987-07-01 | 1989-08-31 | Irm Antriebstech Gmbh | Cup tappet with compensation for hydraulic valve play - take-up plate hardened by plasma discharge |
EP0355360A1 (en) * | 1988-08-24 | 1990-02-28 | Daimler-Benz Aktiengesellschaft | Method for manufacturing tappets for reciprocating-piston engines |
Family Cites Families (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE1808000A1 (en) * | 1968-11-09 | 1970-05-27 | Richard Kuechen Sen | Hydraulic, automatically working valve clearance compensation device |
DE3809702A1 (en) * | 1988-03-23 | 1989-10-05 | Schaeffler Waelzlager Kg | COMPONENT IN THE VALVE CONTROL DRIVE OF AN INTERNAL COMBUSTION ENGINE |
-
1989
- 1989-04-20 IT IT8920214A patent/IT1230012B/en active
-
1990
- 1990-04-20 EP EP90304248A patent/EP0396288B1/en not_active Expired - Lifetime
- 1990-04-20 DE DE90304248T patent/DE69001952T2/en not_active Expired - Fee Related
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0224666A1 (en) * | 1985-11-29 | 1987-06-10 | INA Wälzlager Schaeffler KG | Self adjusting hydraulic valve tappet |
DE3805002A1 (en) * | 1987-07-01 | 1989-08-31 | Irm Antriebstech Gmbh | Cup tappet with compensation for hydraulic valve play - take-up plate hardened by plasma discharge |
EP0355360A1 (en) * | 1988-08-24 | 1990-02-28 | Daimler-Benz Aktiengesellschaft | Method for manufacturing tappets for reciprocating-piston engines |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0443146A1 (en) * | 1990-02-20 | 1991-08-28 | Bayerische Motoren Werke Aktiengesellschaft | Tappet with hydraulic valve lash adjuster |
US5267538A (en) * | 1991-06-07 | 1993-12-07 | Ina Walzlager Schaeffler Kg | Mechanical valve tappet for an internal combustion engine |
EP0566526A1 (en) * | 1992-04-14 | 1993-10-20 | Alusuisse-Lonza Services Ag | Hydraulic valve tappet cup-like housing for internal combustion engines with overhead camshaft |
Also Published As
Publication number | Publication date |
---|---|
DE69001952T2 (en) | 1994-02-03 |
EP0396288B1 (en) | 1993-06-16 |
IT8920214A0 (en) | 1989-04-20 |
IT1230012B (en) | 1991-09-20 |
DE69001952D1 (en) | 1993-07-22 |
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