EP0028736A1 - Poussoir hydraulique - Google Patents

Poussoir hydraulique Download PDF

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Publication number
EP0028736A1
EP0028736A1 EP80106445A EP80106445A EP0028736A1 EP 0028736 A1 EP0028736 A1 EP 0028736A1 EP 80106445 A EP80106445 A EP 80106445A EP 80106445 A EP80106445 A EP 80106445A EP 0028736 A1 EP0028736 A1 EP 0028736A1
Authority
EP
European Patent Office
Prior art keywords
valve
valve member
fluid
cavity
tappet
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Withdrawn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
EP80106445A
Other languages
German (de)
English (en)
Inventor
John J. Krieg
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.)
Eaton Corp
Original Assignee
Eaton Corp
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
Application filed by Eaton Corp filed Critical Eaton Corp
Publication of EP0028736A1 publication Critical patent/EP0028736A1/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Withdrawn legal-status Critical Current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
    • F01L1/20—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

Definitions

  • This invention relates to an improved hydraulic tappet for use in internal combustion engine valve gear and particularly in those engines having lower displacements and higher operating speeds.
  • Pump-up An operating condition known as "pump-up" sometimes occurs in hydraulic tappets during conditions in which engine speeds generally exceed 4000 r.p.m.
  • pump-up occurs an excessive amount of hydraulic fluid enters a cavity within the lifter located between the lifter body and the lower end of the plunger which results in extension of the force transmitting length of the lifter.
  • the excessive length prevents the intake or exhaust valve from completely closing. Failure of the valves to properly seat results in loss of engine power, back firing into the exhaust or intake manifold chamber, and valve burning.
  • ball type check valves are employed pump-up problems can be eliminated by increasing the distance that the ball valve member of the tappet check valve travels. The longer ball travel allows the check valve to be open for a greater period of time, thereby permitting the tappetto "pump down" even after valve gear forces are again transferred through the lifter.
  • a problem associated with providing long ball travel in tappet check valves is that, in some engine applications, the space available for accommodating the increased length of the check valve assembly is not available due to dimensional constraints imposed by existing valve gear components geometry.
  • a hydraulic tappet having a one-way check valve assembly which provides increased ball travel.
  • the check valve assembly includes an open ended cup-shaped spring retainer maintained in abutment with the lower surface of the lifter plunger by a compression biasing spring.
  • a ball valve member is maintained in seating engagement with a valve seat formed around a fluid passageway which connects a fluid reservoir in the plunger with a cavity beneath the plunger.
  • the cavity is defined by the lower end of the plunger and a blind bore formed in the lower end of the lifter body.
  • a conical biasing spring has its major diameter end seated against the bottom end of the cup shaped retainer and its minor diameter end reacting against the ball valve member.
  • the wire diameter, number of coils, and configuration of the conical biasing spring are established by known techniques to permit the spring to compress to a height substantially equivalent to its wire diameter thereby permitting the ball valve member to realize maximum travel away from the valve seat. Slots formed through the side wall of the cup shaped retainer permit the free flow of oil from the reservoir into the cavity.
  • a hydraulic tappet indicated generally at 10, is shown in association with conventional pushrod type valve gear of an internal combustion engine. It should be noted that the principles of the invention are applicable also to other valve gear systems such as stationary lash adjusters for cam-over-rocker type valve gear.
  • the valve gear includes a valve 12 having a stem 14 thereof received in a valve guide 16 formed in a cylinder head 18 of the engine.
  • a valve closing means as, for example, spring 20 is received over the valve stem with a keeper 22 attached thereon to retain the spring, thus causing spring 20 to bias valve 12 to a closed position.
  • a rocker shaft 24 is provided on engine head 18 and individual rocker arms 26 pivot thereabout so as to each have one end thereof contacting the end of the valve stem.
  • the opposite end 28 of each rocker arm is in pivotal contact with a pushrod 30 which extends downwardly through a passage 32 in cylinder head 18 in a manner such that pushrod 30 is free to reciprocate in the cylinder head.
  • a tappet guide bore 34 is provided in an engine block 36 and guide bore 34 has a passage 38 communicating therewith, which passage also communicates with a gallery 40 in a pressurized engine oil pump circuit.
  • Tappet 10 is received slidably in bore 34 and has an end face 42 thereof in contact with a cam surface 44 of a rotating camshaft 46.
  • Cam surface 44 of shaft 46 has a conventional base circle portion 48 and a radially extending lobe portion 50 for causing longitudinal movement of hydraulic tappet 10 within bore 34 during each revolution of the camshaft.
  • Hydraulic tappet 10 has an oil receiving groove 52 provided around the periphery thereof for registering with oil passage 38 as the tappet moves in bore 34 for receiving a supply of pressurized oil from the engine pump circuit to operate the hydraulic lash adjusting means within the tappet.
  • hydraulic tappet 10 is shown in enlarged cross-section as having a body 54.
  • a blind bore 56 is formed in body 54 with the blind end of the bore terminating adjacent cam face 42 of the tappet.
  • Inlet port means are provided in the form of a hole 58 in the wall of the body 54.
  • Oil receiving groove 52 communicates with bore 56 through hole 58 for transmitting metered engine lubricant to the hydraulic lash adjusting means contained therein.
  • the tappet bore 56 has a plunger means 62 slidably received therein.
  • Plunger means 62 is formed of an upper portion 64 and a lower portion 66 which portions are in abutting contact along their respective adjacent transverse faces. At least one, and preferably a plurality, of radial grooves 68 and 70 are formed in the bottom surface of upper plunger portion 64. Plunger means 62 forms, in cooperation with the end of blind bore 56, a cavity 70 for retaining oil therein.
  • a fluid reservoir 72 is defined by plunger means 62.
  • An internal groove 69 formed into bore 56 and a reduced upper diameter portion 71 on lower plunger portion 66 facilitate the flow of oil from oil receiving groove and hole 58 through grooves 68 and 70 and then into fluid reservoir 72.
  • a one-way valve means indicated generally at 74, communicates reservoir 72 with cavity 70 and is in abutment with the lower end of lower plunger portion 66.
  • Valve means 74 has a valve seat 76 formed at the juncture of a passage 77 which fluidly communicates reservoir 72 with cavity 70.
  • a ball valve member 78 is movable from a closed position contacting valve seat 76 to an open position spaced from valve seat 76.
  • a retaining cage 79 is received over ball valve member 78 and serves to retain the ball therein.
  • a conical biasing spring 80 is provided within retaining cage 79 and has a major diameter end 82 in abutment with cage 79 and a minor diameter end 84 in abutment with ball valve member 79.
  • Cage 79 has a plurality of longitudinally extending slots 86 through the side wall thereof, one of which is shown partially in Fig. 3, for permitting the free flow of fluid past cage 78 into cavity 70.
  • Cage 78 has an opening 88 through the lower end thereof for achieving maximum travel of ball valve member 78 away from seat 76 by allowing the lower portion of the ball to extend therein as shown by Fig. 3.
  • Conical spring 80 urges ball valve member 78 to a closed position in contact with valve seat 76.
  • the maximum ball travel necessary to avoid pump-up for a ball having a diameter of 0.2187 inch (5.556 mm) is approximately 0.075 inch (1.905 mm).
  • Pump-up was found to occur when ball travel with a conventional one-way valve assembly was approximately 0.030 inch (0.076 mm).
  • a plunger bias spring 90 is provided in cavity 70 and registers against the lower end of lower plunger portion 66 to urge plunger means 62 in a direction away from the blind end of bore 56.
  • An annular plunger retainer 92 is provided over the upper end of upper plunger portion 64. When no load is present on the plunger means 62 from the associated engine valve gear components, retainer 92 serves to retain the plunger means in body 54 against the bias force of spring 90.
  • the force on pushrod 30 then decreases to a level as determined by the plunger bias spring 90 provided in cavity 70 of the tappet body 54.
  • the plunger bias spring 90 moves the plunger upwardly within the tappet body, thereby causing the plunger to take up any lash in the pushrod-rocker-valve train; and, simultaneously oil is admitted into the cavity 70 through the one-way valve means 74 by the suction formed in cavity 70 due to the outward motion of the plunger means therefrom.
  • the pushrod exerts a force on the plunger means 62 and causes one-way valve means 74 to close, retaining the plunger in its adjusted position by trapping therein the fluid which entered into cavity 70 during the time when the valve means 74 was open.
  • an amount of oil can sometimes flow into the cavity which is in excess of that needed to take up lash in the valve gear.
  • the excess oil volume in cavity 70 causes the force transmitting length to increase which in turn prevents the valve from closing.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Valve-Gear Or Valve Arrangements (AREA)
EP80106445A 1979-11-13 1980-10-22 Poussoir hydraulique Withdrawn EP0028736A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US9378279A 1979-11-13 1979-11-13
US93782 1979-11-13

Publications (1)

Publication Number Publication Date
EP0028736A1 true EP0028736A1 (fr) 1981-05-20

Family

ID=22240686

Family Applications (1)

Application Number Title Priority Date Filing Date
EP80106445A Withdrawn EP0028736A1 (fr) 1979-11-13 1980-10-22 Poussoir hydraulique

Country Status (2)

Country Link
EP (1) EP0028736A1 (fr)
JP (1) JPS5683510A (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2197435A (en) * 1986-10-25 1988-05-18 Teves Gmbh Alfred Pressure control valve

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5832111U (ja) * 1981-08-28 1983-03-02 日鍛バルブ株式会社 内燃機関の動弁機構
JPS6056888B2 (ja) * 1981-10-08 1985-12-12 日産自動車株式会社 ハイドロリツク・リフタ

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3450228A (en) * 1967-07-19 1969-06-17 Gen Motors Corp Hydraulic valve lifter
US3605707A (en) * 1969-12-04 1971-09-20 Eaton Yale & Towne Hydraulic valve lifter with pump-up prevention means
US3967602A (en) * 1974-06-10 1976-07-06 Brown William G Hydraulic valve lifter for reciprocating internal combustion engines
US4083334A (en) * 1973-04-26 1978-04-11 Carlos Alberto Ferrari Roncon Hydraulic valve lifter
US4164917A (en) * 1977-08-16 1979-08-21 Cummins Engine Company, Inc. Controllable valve tappet for use with dual ramp cam

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3450228A (en) * 1967-07-19 1969-06-17 Gen Motors Corp Hydraulic valve lifter
US3605707A (en) * 1969-12-04 1971-09-20 Eaton Yale & Towne Hydraulic valve lifter with pump-up prevention means
US4083334A (en) * 1973-04-26 1978-04-11 Carlos Alberto Ferrari Roncon Hydraulic valve lifter
US3967602A (en) * 1974-06-10 1976-07-06 Brown William G Hydraulic valve lifter for reciprocating internal combustion engines
US4164917A (en) * 1977-08-16 1979-08-21 Cummins Engine Company, Inc. Controllable valve tappet for use with dual ramp cam

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2197435A (en) * 1986-10-25 1988-05-18 Teves Gmbh Alfred Pressure control valve
US4825903A (en) * 1986-10-25 1989-05-02 Alfred Teves Gmbh Pressure control valve
GB2197435B (en) * 1986-10-25 1991-04-24 Teves Gmbh Alfred Pressure control valve

Also Published As

Publication number Publication date
JPS5683510A (en) 1981-07-08

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EP0028736A1 (fr) Poussoir hydraulique

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Designated state(s): DE FR GB IT

17P Request for examination filed

Effective date: 19811030

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN

18D Application deemed to be withdrawn

Effective date: 19830630

RIN1 Information on inventor provided before grant (corrected)

Inventor name: KRIEG, JOHN J.