EP0281990A1 - Compensateur hydraulique de jeu - Google Patents

Compensateur hydraulique de jeu Download PDF

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Publication number
EP0281990A1
EP0281990A1 EP88103558A EP88103558A EP0281990A1 EP 0281990 A1 EP0281990 A1 EP 0281990A1 EP 88103558 A EP88103558 A EP 88103558A EP 88103558 A EP88103558 A EP 88103558A EP 0281990 A1 EP0281990 A1 EP 0281990A1
Authority
EP
European Patent Office
Prior art keywords
hydraulic
compensating element
sleeve part
hydraulic medium
leakage opening
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Withdrawn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
EP88103558A
Other languages
German (de)
English (en)
Inventor
Thomas Feustel
Alois Haberl
Alwin Macht
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.)
Bayerische Motoren Werke AG
Original Assignee
Bayerische Motoren Werke AG
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 Bayerische Motoren Werke AG filed Critical Bayerische Motoren Werke AG
Publication of EP0281990A1 publication Critical patent/EP0281990A1/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Withdrawn legal-status Critical Current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

  • the invention relates to a hydraulic compensating element according to the preamble of claim 1, as it is used, for example, as a clamping compensating element on endless traction mechanisms or as a play compensating element in the valve train of internal combustion engines.
  • a generic clamping compensation element shows, for example, DE-PS 849938; In the valve train, such compensating elements are known both on tappets (for example from DE-OS 34 37 478) or as insertion or support elements on rocker arms or finger levers (for example from DE-OS 34 15 889).
  • Conventional hydraulic compensation elements have a rate of descent that changes with the temperature of the hydraulic medium. That sink rate results from the leakage losses of the hydraulic medium stored in the hydraulic chamber of the compensating element via the annular gap formed by the piston part and sleeve part, and is strongly dependent on the viscosity of the hydraulic medium and thus on its temperature. For example, with conventional compensation elements at a temperature of the hydraulic medium of 20 ° C a sink rate of 1 mm was found in 100 seconds, while at a temperature of 120 ° C the sink rate of 1 mm was already reached within 10 seconds.
  • the lubricating oil of the machine is mostly used as the hydraulic medium, which, however, has a significantly higher viscosity when the internal combustion engine is cold than when the engine is at operating temperature. The result is very different sink rates over the operating temperature. This is extremely disadvantageous both on tension compensation elements and on play compensation elements. In the former case, the traction mechanism drive is overstressed as a result of reactions to load changes that cannot be determined exactly; in the valve train of an internal combustion engine, the valve control times inevitably change as they heat up. This is also undesirable because of the increase in wear and the influence on the gas exchange.
  • a remedial measure was known from DE-PS 823538. It proposes a play compensation element, the piston part of which is made of a material whose coefficient of thermal expansion is higher than that of the material used for the sleeve part. When the hydraulic medium and the compensating element are heated, the piston part thus expands more than the sleeve part, as a result of which the cross section of the annular gap formed by these two parts is reduced. The decreasing viscosity with increasing heating of the hydraulic medium as well as the resulting increased leakage losses are thus compensated for by a reduction in the leakage cross-section. Even though the proposed solution to achieve a constant rate of descent is astounded by its simplicity, such a compensation element cannot fully meet the requirements. Experiments and calculations have shown that it is not possible to achieve a rate of descent that is completely independent of the temperature of the hydraulic medium. The results that can be achieved with that element do not justify the increased construction effort.
  • the object of the invention is to provide an improved hydraulic compensation element which, in the cold operating state and in particular in the case of a cold hydraulic medium, has an at least approximately the same rate of descent as in the completely heated operating state with likewise heated hydraulic medium. This object is achieved by the characterizing features of the first claim.
  • the annular gap formed by the piston part and the sleeve part preferably serves as the leakage opening.
  • the regulating body is preferably designed as a tension ring which promotes the thermal expansion of the piston part or reduces that of the sleeve part.
  • the clamping ring can be arranged within the piston part, in the latter case it envelops the sleeve part in some areas.
  • sleeve part 1 consists essentially of the sleeve part 1 and the piston part 2, which is guided longitudinally displaceably therein, which is designed here as divided and is composed of a piston lower part 2a and a piston upper part 2b. The latter is led out of the sleeve part and provided with a ball socket 3 for supporting a rocker arm, not shown, of an internal combustion engine valve train, also not shown.
  • the piston part 2 and the sleeve part 1 form the hydraulic chamber 4, which is filled via a bore 6 provided with a check valve 5 (consisting of a spring 5a and a sealing ball 5b).
  • the volume of this hydraulic chamber 4 finally determines the total length L of the compensating element, so that the desired length compensation can take place by appropriately filling the hydraulic chamber.
  • these leakage losses remain almost constant regardless of changing temperatures of the hydraulic medium if the cross-section of the annular gap 7 decreases with increasing temperature of the hydraulic medium.
  • a reduction is achieved in that the piston part 2 expands more than the sleeve part 1 when heated.
  • the lower piston part 2 a is provided with a clamping ring 8, which has a higher coefficient of thermal expansion than the piston part 2 or the sleeve part 1.
  • the heating hydraulic medium also heats the sleeve part 1, the piston lower part 2a, and the clamping ring 8, whereby the components mentioned expand.
  • the clamping ring 8 expands more than the lower piston part 2a and the sleeve part 1 and thus mechanically brings about an additional expansion of the piston lower part 2a, whereby the cross section of the annular gap 7 is reduced.
  • FIG. 2 A further exemplary embodiment is shown in FIG. 2.
  • the same reference numbers are used on the hydraulic tensioning compensation element for the same components.
  • a coil spring 10 is provided within the hydraulic space 4 to apply the required clamping force.
  • a separate leakage opening 11 is provided to achieve a constant sink rate, in the mouth region of which a control body 12 forms a throttle gap 13.
  • the control body 12 is suspended within a cage 14, which is provided with openings 15 to the hydraulic chamber 4, so that there is a continuous hydraulic connection between the hydraulic chamber 4 and the leakage opening 11.
  • the hydraulic flow flowing through that leakage opening 11 is determined by the cross section of the Throttle gap 13 determined.
  • control body expands more than the piston part 2 or the sleeve part 1 due to its higher coefficient of thermal expansion with heating of the hydraulic medium, the throttle gap 13 narrows. Despite a decreasing viscosity, an approximately constant amount of hydraulic medium flows over that leak opening 11. The rate of descent of that tension compensation element can thus be kept constant. It is also important here that, in addition to the first influencing parameter of the different thermal expansion coefficients, there is a second influencing parameter in the form of the geometry of control body 12 and leakage opening 11 or throttle gap 13.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Valve Device For Special Equipments (AREA)
  • Valve-Gear Or Valve Arrangements (AREA)
EP88103558A 1987-03-11 1988-03-08 Compensateur hydraulique de jeu Withdrawn EP0281990A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3707776 1987-03-11
DE3707776 1987-03-11

Publications (1)

Publication Number Publication Date
EP0281990A1 true EP0281990A1 (fr) 1988-09-14

Family

ID=6322761

Family Applications (1)

Application Number Title Priority Date Filing Date
EP88103558A Withdrawn EP0281990A1 (fr) 1987-03-11 1988-03-08 Compensateur hydraulique de jeu

Country Status (1)

Country Link
EP (1) EP0281990A1 (fr)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19627982A1 (de) * 1996-07-11 1998-01-15 Schaeffler Waelzlager Kg Hydraulisches Spielausgleichselement
US6039018A (en) * 1999-02-18 2000-03-21 General Motors Corporation Hydraulic lash adjuster with plunger inner control ring
US6119644A (en) * 1997-05-22 2000-09-19 Ina Walzlager Schaeffler Ohg Hydraulic clearance compensation element
DE10005073A1 (de) * 2000-02-04 2001-09-20 Schaeffler Waelzlager Ohg Spanneinrichtung für Zugmittel wie Riemen und Ketten
WO2005068793A1 (fr) * 2004-01-19 2005-07-28 Toyota Jidosha Kabushiki Kaisha Mecanisme d'actionnement de soupape variable pour moteur a combustion interne
DE102008004169B4 (de) * 2007-04-04 2020-12-03 Iwis Motorsysteme Gmbh & Co. Kg Spannvorrichtung mit temperaturabhängigem Ventil

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2964027A (en) * 1958-03-19 1960-12-13 Johnson Products Inc Valve for metering lubricating oil from a hydraulic tappet to a hollow push rod
DE1425653A1 (de) * 1963-07-08 1969-01-23 Richard Kuechen Sen Ventilantrieb mit hydraulischem Spielausgleich

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2964027A (en) * 1958-03-19 1960-12-13 Johnson Products Inc Valve for metering lubricating oil from a hydraulic tappet to a hollow push rod
DE1425653A1 (de) * 1963-07-08 1969-01-23 Richard Kuechen Sen Ventilantrieb mit hydraulischem Spielausgleich

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN, Band 11, Nr. 114 (M-579)[2561], 10. April 1987; & JP-A-61 258 911 (HONDA MOTOR CO. LTD) 17-11-1986 *
PATENT ABSTRACTS OF JAPAN, Band 8, Nr. 104 (M-296)[1541], 16. Mai 1984; & JP-A-59 015 614 (ATSUGI JIDOUSHIYA BUHIN K.K.) 26-01-1984 *

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19627982A1 (de) * 1996-07-11 1998-01-15 Schaeffler Waelzlager Kg Hydraulisches Spielausgleichselement
US6119644A (en) * 1997-05-22 2000-09-19 Ina Walzlager Schaeffler Ohg Hydraulic clearance compensation element
US6039018A (en) * 1999-02-18 2000-03-21 General Motors Corporation Hydraulic lash adjuster with plunger inner control ring
DE10005073A1 (de) * 2000-02-04 2001-09-20 Schaeffler Waelzlager Ohg Spanneinrichtung für Zugmittel wie Riemen und Ketten
WO2005068793A1 (fr) * 2004-01-19 2005-07-28 Toyota Jidosha Kabushiki Kaisha Mecanisme d'actionnement de soupape variable pour moteur a combustion interne
DE102008004169B4 (de) * 2007-04-04 2020-12-03 Iwis Motorsysteme Gmbh & Co. Kg Spannvorrichtung mit temperaturabhängigem Ventil

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