EP0044922B1 - Elément commutateur à membrane pour l'actionnement d'un dispositif indicateur - Google Patents

Elément commutateur à membrane pour l'actionnement d'un dispositif indicateur Download PDF

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Publication number
EP0044922B1
EP0044922B1 EP81104351A EP81104351A EP0044922B1 EP 0044922 B1 EP0044922 B1 EP 0044922B1 EP 81104351 A EP81104351 A EP 81104351A EP 81104351 A EP81104351 A EP 81104351A EP 0044922 B1 EP0044922 B1 EP 0044922B1
Authority
EP
European Patent Office
Prior art keywords
diaphragm
circumferential bead
pressure differential
membrane
end position
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.)
Expired
Application number
EP81104351A
Other languages
German (de)
English (en)
Other versions
EP0044922A1 (fr
Inventor
Hellmuth Dipl.-Ing. Gutjahr
Ditrich Dipl.-Ing. Lenzen
Berthold Pscheidt
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.)
Knecht Filterwerk GmbH
Original Assignee
Knecht Filterwerk GmbH
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 Knecht Filterwerk GmbH filed Critical Knecht Filterwerk GmbH
Publication of EP0044922A1 publication Critical patent/EP0044922A1/fr
Application granted granted Critical
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Expired legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M35/00—Combustion-air cleaners, air intakes, intake silencers, or induction systems specially adapted for, or arranged on, internal-combustion engines
    • F02M35/02—Air cleaners
    • F02M35/08—Air cleaners with means for removing dust, particles or liquids from cleaners; with means for indicating clogging; with by-pass means; Regeneration of cleaners
    • F02M35/09—Clogging indicators ; Diagnosis or testing of air cleaners

Definitions

  • the invention relates to a diaphragm switching element for actuating a differential pressure-controlled display device for excessive contamination of an intake air filter of an internal combustion engine according to the preamble of claim 1.
  • Such a display device is e.g. B. known from DE-B 12 32 788.
  • the vacuum chamber and atmosphere are separated by a so-called inverted membrane, which is spring-loaded.
  • a kind of pin is articulated in the center of the diaphragm, which follows the deflection of the diaphragm center and triggers an optical display when the diaphragm is in a corresponding position.
  • the pen for the optical display of the vacuum is subject to slight vibrations. As long as it is a purely optical display, this is no longer a problem because of the low vibration deflection.
  • a vibration of the indicator pin is disadvantageous if the pin is not intended to give an optical indicator signal, but is used to actuate an electrical contact to trigger an indicator signal when a certain differential pressure is exceeded. This is because the vibrations in the switching area lead to undesirable contact fluctuations, which lead to premature wear of the contacts.
  • the essential feature of this device is the use of a plate-shaped membrane, taking advantage of its residual stresses present in certain positions to stabilize the contactor at the time of switching, ie. H. when the specified differential pressure value triggering the display is exceeded.
  • This is achieved in that the plate membrane is installed in such a way that, in the absence of differential pressure, it is biased in its end position opposite the tension-free final resting position by the spring which loads it.
  • the membrane center moves towards the tension-free final resting position of the membrane.
  • the membrane passes through an unstable area in which its internal stresses cancel each other out in the axial direction.
  • the diaphragm is now adjusted by means of the springs which load it so that the pressure difference value, above which a display signal is to be triggered, comes to lie in the so-called unstable region of the diaphragm.
  • Exceeding the pressure difference value means that the effect of the negative pressure is further supported by the potential energy released in the direction of the final resting position after the unstable position in the membrane has been exceeded. This results in a kind of snap effect, which leads to a vibration-free closing of the electrical contact for triggering the display signal as in the toggle switches known in electrical engineering.
  • the decreasing differential pressure in a transition area also counteracts the membrane force that is required to re-tension the membrane force.
  • a truncated cone-shaped membrane in the idle state is known from DE-U 7 005 833, but this membrane is not prestressed by a spring in the installed state. It is therefore in the relaxed final resting position when there is no pressure difference.
  • An internal combustion engine 1 is connected to an intake air filter 5 via an intake duct 2, into which the membrane switching element 3 according to the invention protrudes, and a carburetor 4 with a throttle valve which can be actuated at will.
  • the intake air filter 5 is divided by a filter insert 6 into a clean air space 7 and a raw air space 8.
  • the membrane switching element 3 consists of a two-part housing made of the upper housing part 9 and lower housing part 10, which are connected to one another by a snap connection.
  • a plate-shaped membrane 12 made of elastic material, for. B. silicone rubber, with its outer, annular peripheral bead 13 tightly clamped and divides the housing into two chambers 14, 15.
  • One chamber 14 communicates with the surrounding atmosphere and the other chamber 15 communicates with the intake duct 2 via an opening 16.
  • the truncated cone-shaped membrane 12 according to FIG. 3 in its relaxed state has, in addition to the outer circumferential bead 13, a lateral surface 17 which connects the outer circumferential bead 13 to an inner, annular circumferential bead 18.
  • a multiple offset, shouldered, partially hollow shift rod 19 is guided in its lower, perforated sleeve-shaped end 20 in the lower housing part 10.
  • a compression spring 22 rests on a shoulder 21, which is supported at its other end on the lower housing part 10.
  • a contact disk 26 which is acted upon by a compression spring 25, loosely rests and limits the stroke of the shift rod 19 by contacting a shoulder 27 of the upper housing part 9.
  • Two contact brackets 28, 29 are clamped in the parting plane 11 between the upper and lower parts of the housing and each have an angled part 30, 31 with which the contact disk 26 can be brought into contact to trigger a switching signal.
  • the membrane 12 is sealingly connected to the shift rod 19 with its inner, annular peripheral bead 18.
  • the membrane 12 When assembling the membrane switching element 3, the membrane 12 is inserted as shown in FIG. 3.
  • the inner circumferential bead 18, viewed axially, lies in a plane below the plane in which the outer circumferential bead 13 lies.
  • the compression spring 22 is designed so that when the membrane switching element 3 is assembled, the maximum pressure present in the intake duct of z. B. balances 35 millibars and the switching mechanism assumes a position as shown in Fig. 2.
  • the axial upward stroke of the shift rod 19 is limited by the contact disk 26 being placed on the shoulder 27 of the upper housing part 9.
  • the setting of the switching point takes place after the assembly of the membrane switching element in an adjustment process, in which to the chamber 15 the vacuum corresponding to the switching point of z. B. 50 mbar is applied at a certain ambient temperature, by biasing the compression spring 25th
  • the position of the membrane 12 in the housing 9, 10 is chosen so that the negative pressure of 50 mbar, beyond which the electrical contact to trigger the display signal is to be closed, is then applied to the membrane 12 when it is just in their unstable liner. If this target differential pressure is exceeded, not only the resulting force from the negative pressure and the force of the springs acting on the diaphragm, but also the potential energy of the residual stresses in the diaphragm itself, which wants to bring the diaphragm to rest, acts on the contact can assume a value of approximately 3 mbar in the present case. As a result, when the electrical contact is triggered once, negative pressure drops of up to 3 mbar, as can easily occur due to pulsations, do not take effect. H. they do not open the contact. Rather, the contact can only be opened again when the pressure decrease the value from here z. B. exceeds 3 mbar.
  • the electrical contact for triggering the display signal is brought about in that the contact disk 26 connects the contact brackets 28, 29 to one another.
  • the electrical switching signal can, for. B. a visual display on the dashboard of the vehicle.

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Measuring Fluid Pressure (AREA)
  • Filtering Of Dispersed Particles In Gases (AREA)
  • Switches Operated By Changes In Physical Conditions (AREA)

Claims (2)

1. Elément commutateur à membrane pour l'actionnement d'un dispositif commandé par pression différentielle indiquant un encrassement excessif d'un filtre (5) d'air d'aspiration d'un moteur à combustion interne (1) comportant une membrane (12) en un matériau élastique qui, coincée par son bourrelet périphérique (13) dans un boîtier (9, 10), subdivise ce dernier en deux chambres (14, 15) et est articulée en son centre sur une tige de commutation (19) qui, actionnable perpendiculairement au plan de coincement et chargée élastiquement, suit le mouvement du centre de la membrane (12) avec le bourrelet périphérique interne (18), résultant de la différence de pression entre les deux chambres (14, 15), et provoque un affichage lorsqu'est dépassée une différence de pression prédéterminée, élément caractérisé par la combinaison des caractéristiques suivantes :
a) la membrane (12) est en forme de coupelle elle est réalisée tronconique à l'état détendu et est incorporée de telle façon qu'elle se trouve, en l'absence d'une différence de pression entre les deux chambres (14,15), dans sa position extrême (12 sur la Fig. 2) opposée à sa position extrême de repos détendue (12 sur la Fig. 3) et que, lorsque la différence de pression augmente, elle traverse de part en part le plan de coincement de son bourrelet périphérique externe (13) en décalant son centre avec le bourrelet périphérique interne (18) et se déplace vers sa position extrême détendue (12 sur la Fig.3) en franchissant une position intermédiaire instable,
b) la force élastique (22, 25) appliquée à la membrane (12) est conçue de telle sorte que, en présence de la différence de pression lors du dépassement de laquelle la tige de commutation (19) doit déclencher un affichage, la membrane (12) se trouve dans sa position intermédiaire instable à partir de laquelle elle a tendance à gagner sa position extrême de repos détendue (12 sur la Fig. 3) lorsque la différence de pression continue d'augmenter, avec le concours de l'énergie potentielle qu'elle accumule et qui est alors libérée,
c) la tige de commutation (19) articulée sur la membrane (12) actionne un contact électrique (26, 31) en vue de l'affichage de la différence de pression prédéterminée qui a été dépassée.
2. Elément commutateur à membrane selon la revendication 1, caractérisé par le fait que, dans la position intermédiaire instable de la membrane (12), le bourrelet périphérique interne (18) et le bourrelet périphérique externe (13) se trouvent sensiblement dans un plan (11).
EP81104351A 1980-07-30 1981-06-05 Elément commutateur à membrane pour l'actionnement d'un dispositif indicateur Expired EP0044922B1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE19803028858 DE3028858A1 (de) 1980-07-30 1980-07-30 Membran-schaltelement zur betaetigung einer anzeigevorrichtung
DE3028858 1980-07-30

Publications (2)

Publication Number Publication Date
EP0044922A1 EP0044922A1 (fr) 1982-02-03
EP0044922B1 true EP0044922B1 (fr) 1984-01-18

Family

ID=6108457

Family Applications (1)

Application Number Title Priority Date Filing Date
EP81104351A Expired EP0044922B1 (fr) 1980-07-30 1981-06-05 Elément commutateur à membrane pour l'actionnement d'un dispositif indicateur

Country Status (2)

Country Link
EP (1) EP0044922B1 (fr)
DE (2) DE3028858A1 (fr)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5036698A (en) * 1990-05-04 1991-08-06 Allied-Signal Inc. Method and apparatus for predicting life of air filter cartridges
JP2008531241A (ja) 2005-01-28 2008-08-14 エンジニアード プロダクツ カンパニー フィルタ監視用の無ロックスイッチ

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1232788B (de) * 1962-10-15 1967-01-19 Bacharach Ind Instr Company Saugdruckmesser
US3312187A (en) * 1966-02-02 1967-04-04 Ford Motor Co Fluid filter assembly having a warning indicator
US3556043A (en) * 1968-12-16 1971-01-19 Ambac Ind Filter gauge
DE7005833U (de) * 1970-02-19 1970-05-21 Vdo Schindling Membran fuer ein durch unterdruck betaetigbares schaltorgan.

Also Published As

Publication number Publication date
EP0044922A1 (fr) 1982-02-03
DE3161947D1 (en) 1984-02-23
DE3028858A1 (de) 1982-02-18

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