(19)
(11)EP 2 151 612 B1

(12)EUROPEAN PATENT SPECIFICATION

(45)Mention of the grant of the patent:
08.11.2017 Bulletin 2017/45

(21)Application number: 08711799.0

(22)Date of filing:  22.02.2008
(51)International Patent Classification (IPC): 
F16J 15/324(2016.01)
F16J 15/3244(2016.01)
(86)International application number:
PCT/JP2008/053025
(87)International publication number:
WO 2008/126478 (23.10.2008 Gazette  2008/43)

(54)

OIL SEAL

ÖLDICHTUNG

JOINT ÉTANCHE À L'HUILE


(84)Designated Contracting States:
AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MT NL NO PL PT RO SE SI SK TR

(30)Priority: 11.04.2007 JP 2007103436

(43)Date of publication of application:
10.02.2010 Bulletin 2010/06

(73)Proprietor: NOK Corporation
Minato-ku Tokyo 105-8585 (JP)

(72)Inventors:
  • MATSUI, Hiroki
    Fukushima-shi Fukushima 960-1102 (JP)
  • TANIDA, Masayuki
    Fukushima-shi Fukushima 960-1102 (JP)
  • MIZUTA, Hirotaka
    Fujisawa-shi Kanagawa 251-0042 (JP)
  • FURUYAMA, Hideyuki
    Fukushima-shi Fukushima 960-1102 (JP)
  • YOSHIKAWA, Ken
    Fukushima-shi Fukushima 960-1102 (JP)
  • SATO, Yuki
    Fujisawa-shi Kanagawa 251-0042 (JP)

(74)Representative: TBK 
Bavariaring 4-6
80336 München
80336 München (DE)


(56)References cited: : 
EP-A1- 1 479 949
EP-A2- 0 939 257
JP-A- 08 159 294
JP-A- 11 311 338
JP-A- 2005 172 061
US-B1- 6 726 211
EP-A1- 1 698 809
FR-A1- 2 456 888
JP-A- 08 178 082
JP-A- 2002 022 027
JP-U- 06 056 568
  
      
    Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention).


    Description

    BACKGROUND OF THE INVENTION


    Field of the Invention



    [0001] The present invention relates to an oil seal which is a kind of a sealing device. For example, the oil seal of the present invention is used in a field relating to an automobile or in a field of a general purpose machine and the like.

    Description of the Conventional Art



    [0002] An oil seal is generally required to have low torque characteristics so as to suppress sliding abrasion of a seal lip. In order to obtain low torque characteristics, a technique for reducing fastening force by reducing a cross section of a seal lip or the like, and a technique for reducing a friction coefficient by change of a material, modification of a surface (for example, coating of a fluorine resin) and the like have been discussed. However, in order to realize more excellent low torque characteristics, it is considered to realize low torque characteristics based on fluid lubrication by increasing the thickness of an oil film on a sliding surface.

    [0003] Fig. 6 illustrates a conventional technique developed. In this technique, screw sections 54 and 55 are provided on a slope 52 at the side of sealed fluid and a slope 53 at the side opposite to the sealed fluid of a seal lip 51 respectively, and a pumping effect induced by the screw sections 54 and 55 pushes back the sealed fluid toward the side of the sealed fluid (refer to the patent document 1).
    Patent Document 1: Japanese Utility Model Application Laid-Open No. 3-29768

    [0004] According to this technique, since the pumping effect induced by screw sections 54 and 55 pushes back the sealed fluid toward the side of the sealed fluid, sealing property increases. However, since the thickness of the oil film on the sliding surface necessarily decreases, low torque characteristics based on fluid lubrication can not be realized.

    [0005] Further, the patent document 2 describes a technique, in which an intermediate surface is provided between a slope at the side of sealed fluid and a slope at the side opposite to the sealed fluid. However, this prior art is not to provide a reverse screw section on the intermediate surface.
    Patent Document 2: Japanese Patent Application Laid-Open No. 2003-254439

    [0006] An oil seal according to the preamble of claim 1 is known from patent document 3.

    [0007] Patent Document 3: EP 1479949 A1

    [0008] A further oil seal is known from patent document 4.

    [0009] Patent Document 4: FR 2 456 888 A1

    SUMMARY OF THE INVENTION


    Problems to be Solved by the Invention



    [0010] The present invention is to solve the aforementioned problems, and aims to obtain an oil seal having low torque characteristics based on fluid lubrication by increasing the thickness of an oil film on a sliding surface.

    Means for Solving the Problem



    [0011] In order to achieve the objective, an oil seal according to claim 1 of the present invention has a seal lip in slidably close contact with a circumferential surface of a mating member such as an shaft, a slope at the side of sealed fluid and a slope at the side opposite to the sealed fluid both of which are provided on the seal lip, and a screw section provided on the slope at the side opposite to the sealed fluid to perform a function of pushing back sealed fluid by a pumping effect induced at a time of rotation, wherein an intermediate surface is provided between a slope at the side of the sealed fluid and a slope at the side opposite to the sealed fluid, the intermediate surface is in surface contact with the circumferential surface of the mating member along a predetermined axial direction width, and an oppositely threaded screw section for performing a function of sucking the sealed fluid by a pumping effect induced at a time of rotation is provided on the intermediate surface. The oppositely threaded screw section provided on the intermediate surface is provided in such a way that the oppositely threaded screw section does not reach a boundary between the intermediate surface and the slope at the side opposite to the sealed fluid, so that a threadless region lying in the entire circumference between the screw section and the boundary and being in close contact with the circumferential surface of the mating member is provided.

    Effect of the Invention



    [0012] The oil seal of the present invention having the aforementioned configuration has an intermediate surface between the slope at the side of the sealed fluid and the slope at the side opposite to the sealed fluid of the seal lip, and the intermediate surface has a predetermined axial direction width and is in close contact with the circumferential surface of the mating member. Thus, the seal lip can stably contact the mating member with suppressed sliding abrasion. Further, an oppositely threaded screw section (which will be also called "a reverse screw section" below) is provided on the intermediate surface and performs a function of sucking the sealed fluid by a pumping effect induced at a time of rotation. Thus, the sealed fluid is positively introduced to the intermediate surface by the pumping effect induced by the reverse screw section, dynamic pressure is generated on the intermediate surface, and the thickness of the oil film thus increases. The intermediate surface is parallel to a center axial line of the oil seal. Therefore, according to this oil seal, since a portion having the thick oil film lies in a wide region, the oil seal can have low torque characteristics based on fluid lubrication which is the objective of the present invention. Further, since the pumping effect induced by the screw section (which will be called also "a normal screw section" below) provided on the slope at the side opposite to the sealed fluid pushes back the sealed fluid introduced to the intermediate surface, the sealed fluid does not leak toward the side opposite to the sealed fluid.

    [0013] Further, since a threadless region lies at the side opposite to the sealed fluid of the reverse screw section on the intermediate surface, so-called static leakage can be prevented.

    [0014] In addition, as described above, the intermediate surface is parallel to a center axial line of the oil seal.

    BRIEF EXPLANATION OF DRAWINGS



    [0015] 

    [Fig. 1] A sectional view of main part of an oil seal according to an example which is useful for understanding the present invention but not claimed.

    [Fig. 2] A view of main part of the same oil seal.

    [Fig. 3] A view illustrating main part of an oil seal according to the present invention.

    [Fig. 4] A view illustrating main part of an oil seal according to another example which is useful for understanding the present invention but not claimed.

    [Fig. 5] A view illustrating a sloping angle of an intermediate surface in (A), (B) and (C).

    [Fig. 6] A sectional view of main part of an oil seal according to a conventional embodiment.


    Explanation of Reference Numerals



    [0016] 

    1: Oil seal

    2: Metal ring

    3: Rubber-like elastic body

    4: Outer circumferential seal section

    5: Dust lip

    6: Seal lip

    7: Slope at the side of sealed fluid

    8: Slope at the side opposite to sealed fluid

    9: Screw section

    10: Intermediate surface

    11, 11A, 11B: Oppositely threaded screw sections (reverse screw sections)

    12, 13: Boundaries

    14: Threadless region


    DETAILED DESCRIPTION OF PREFERRED EMBODIMENT



    [0017] The present invention includes the following embodiment.
    Relating to claim 1:
    1. (1) The low torque characteristics are realized by making a lip to have a geometric shape and increasing a thickness of an oil film.
    2. (2) In order to increase the thickness of an oil film on a lip sliding surface and hold a sealing property, a lip shape is made such that an oppositely threaded screw, for example, is provided on a flat section (an intermediate surface) having a flat lip shape, and a conventional screw is provided on a section at the atmosphere side (a slope at the side opposite to sealed fluid).
    3. (3) Dynamic pressure on the sliding surface is generated by making the sealed fluid to freely leak by the reverse screw section, and the thickness of the oil film thus increases. Thus, the low torque characteristics can be expected.
    4. (4) A contact width of the reverse screw section expands by making the lip shape to be a flat shape, and a thick portion of the oil film on the sliding surface can also expand.
    5. (5) In order to prevent the total leakage at the lip, pumping force (discharge force) of the screw provided on the section at the atmosphere side is set to be larger than pumping force (suction force) of the reverse screw provided on the flat section.
    6. (6) The thickness of the oil film on the sliding surface is increased by providing the reverse screw section on the flat lip portion, and the low torque characteristics can be realized. However, when the screw section penetrates the entire sliding width, the static leakage could occur. Consequently, the screw section stops at a middle of the sliding width, and the static leakage is thus prevented. Furthermore, a non-penetrating region does not come to be at the same portion with respect to the sliding width, both an effect for increasing the oil film and an effect for preventing the static leakage can be obtained.


    [0018] Relating to an example which is useful for understanding the present invention:

    (7) Conventionally, the intermediate surface has an angle at the atmosphere side (the side opposite to sealed fluid), and the seal lip slides on a line between the intermediate surface and the oil side surface (the slope at the side of sealed fluid). Therefore, an effect induced by the screw appears almost only at the atmosphere side, and the oil film on the sliding section is thin. Thus, there is a fault that the torque is high.

    (8) Consequently, the intermediate surface is provided between the oil side surface (the slope at the side of sealed fluid) and the atmosphere side surface (the slope at the side opposite to the sealed fluid) and has an angle (being more than 0 degree to 25 degrees or less, preferably 0.1 degrees or more to 20 degrees or less) at the oil side in a mounted state. Further, a reverse screw is provided on the intermediate surface.

    (9) The lip sides between the atmosphere side surface (the slope at the side opposite to the sealed fluid) having a normal screw and the intermediate surface having a reverse screw. Oil (sealed fluid) is gathered in a sliding line by an effect induced by the normal screw at the atmosphere side and the reverse screw on the intermediate surface. Thus, the thickness of the oil film on the sliding section increases, and torque comes to be low. The sealing property can be held by the pumping effect induced by the normal screw at the atmosphere side, and both the sealing property and the low torque can be thus obtained.

    (10) The intermediate surface is provided between the oil side surface (the slope at the side of sealed fluid) and the atmosphere side surface (the slope at the side opposite to the sealed fluid) and has an angle (being more than 0 degree to 25 degrees or less, preferably 0.1 degrees or more to 20 degrees or less) at the oil side in a mounted state. The normal screw is provided on the atmosphere side surface, and the reverse screw is provided on the intermediate surface. A type of the screw does not matter (for example, the normal screw has a ship bottom shape, and the reverse screw has a parallel shape). The lip slides on a line between the atmosphere side surface having the normal screw and the intermediate surface having the reverse screw. Oil (sealed fluid) is gathered on a sliding line by an effect induced by the normal screw at the atmosphere side and the reverse screw on the intermediate surface. Thus, the thickness of the oil film on the sliding section increases, and low torque is obtained. The sealing property can be held by the pumping effect induced by the normal screw at the atmosphere side, and both the sealing property and the low torque can be thus obtained. Furthermore, because of low torque, heat generation by sliding is low. Because of thick oil film, the oil seal has low abrasion, and thus has a long life.


    Example



    [0019] Examples of the present invention will be described below with reference to the drawings.

    [0020] Fig. 1 illustrates a section of main part of an oil seal 1 according to the example which is useful for understanding the present invention. The oil seal 1 according to the examples has a following configuration.

    [0021] The oil seal 1 has an outer circumferential seal section 4 and a dust lip 5 which are provided with a rubber-like elastic body 3 bonded (vulcanized and bonded) to a metal ring 2. In addition, the oil seal 1 has a seal lip 6 in slidably close contact with the circumferential surface of a shaft (a mating member, not illustrated). The seal lip 6 has a slope 7 at the side of sealed fluid and a slope 8 at the side opposite to the sealed fluid which are provided on a top end sliding section of the seal lip 6. The latter, i.e. the slope 8 at the side opposite to the sealed fluid, has a screw section (normal screw section) 9 for performing a function of pushing back the sealed fluid by a pumping effect induced at a time of by rotation. The normal screw section 9 consists of a plurality of spiral protrusions provided on the circumferential surface and having a ship bottom shape specifically in this figure. The height of a screw thread is about 180 to 240µm in actual dimension.

    [0022] Further, a cylindrical intermediate surface (flat surface) 10 is provided between the slope 7 at the side of sealed fluid and the slope 8 at the side opposite to the sealed fluid, and is in surface contact with the circumferential surface of the shaft along a predetermined axial direction width L. An oppositely threaded screw section (reverse screw section) 11 is provided on the intermediate surface 10, and performs a function of sucking the sealed fluid by a pumping effect induced at time of rotation. The reverse screw section 11 consists of a plurality of spiral protrusions provided on the circumferential surface. In this figure, since the thicknesses of the protrusions are thin, the protrusion is illustrated with one line. The height of a screw thread is about 20 to 35µm in actual dimension. The axial direction width L of the intermediate surface 10 is about 0.5 mm (0.1 to 1.0 mm) in actual dimension.

    [0023] As for a direction of spiral, the screw section 9 is set in the direction which inclines frontward in the axis rotation direction (refer to an arrow in Fig. 2) from an end section at the side opposite to the sealed fluid to an end section at the side of the sealed fluid, and, to the contrary, the reverse screw section 11 is set in the direction which inclines backward in the axis rotation direction from the end section at the side opposite to the sealed fluid to the end section at the side of the sealed fluid.

    [0024] In the oil seal 1 having the aforementioned configuration, the intermediate surface 10 in surface contact with the circumferential surface of the shaft along the predetermined axial direction width L is provided between the slope 7 at the side of the sealed fluid and the slope 8 at the side opposite to the sealed fluid of the seal lip 6. Thus, the seal lip 6 stably contacts the shaft with the suppressed sliding abrasion. In addition, the reverse screw section 11 is provided on the intermediate surface 10, and performs a function of sucking the sealed fluid by the pumping effect induced at a time of rotation of the shaft. Thus, the sealed fluid is positively introduced onto the intermediate surface 10 by the pumping effect of the reverse screw section 11, a dynamic pressure is generated on the intermediate surface 10, and the thickness of an oil film increases. Therefore, since a portion having the thick oil film is formed in a wide region, the low torque characteristics based on fluid lubrication is realized. In addition, since the sealed fluid introduced onto the intermediate surface 10 is pushed back by the pumping effect of the screw section 9 provided on the slope 8 at the side opposite to the sealed fluid, the sealed fluid does not leak to the side opposite to the sealed fluid. In order to complete this sealing property, the pumping force of the screw section 9 is set larger than the pumping force of the reverse screw section 11.

    [0025] As for the oil seal 1 according to the aforementioned example, it can be considered that the configuration thereof is changed and/or added as follows.

    [0026] In the aforementioned example, the reverse screw section 11 consists of a plurality of spiral protrusions provided on the circumferential surface, as illustrated in an expanding way in Fig. 2. However, as illustrated in Fig. 3, the reverse screw section 11 can consists of a plurality of spiral grooves (recessions) provided on the circumferential surface instead of the spiral protrusions. The reverse screw section 11 can perform a pumping effect like the case of the protrusions even if the grooves are provided. Further, if the reverse screw section 11 consists of the grooves, the reverse screw section 11 can hold the sealed fluid (oil) in the grooves. Thus, even when supplying of the sealed fluid is a little, the sliding surface can hold lubrication, and the damage of the seal due to abrasion can decrease even at a time of poor lubrication.

    [0027] Further, in the aforementioned example which is useful for understanding the invention, the reverse screw section 11 reaches a boundary 13 between the intermediate surface 10 and the slope 8 at the side opposite to the sealed fluid from a boundary 12 between the intermediate surface 10 and the slope 7 at the side of the sealed fluid, as illustrated in an expanding way in Fig. 2. However, instead of such, as illustrated in Fig. 3 and according to the invention, the reverse screw section 11 can be provided in such a way that the reverse screw section 11 does not reach the boundary 13 between the intermediate surface 10 and the slope 8 at the side opposite to the sealed fluid, and a belt-like threadless region 14, which lies in the entire circumference between the reverse screw section 11 and the boundary 13 and is in close contact with the circumferential surface of the shaft, is thus provided. When the threadless region 14 lying in the entire circumference is provided in such a configuration, the threadless region 14 performs a function as a seal dam. Thus, so-called static leakage at a time of stopping the rotation of the shaft can be prevented.

    [0028] Furthermore, as illustrated in Fig. 4 and according to another example which is useful for understanding the invention but not claimed, a reverse screw section 11A is provided in such a way that the reverse screw section 11A does not reach the boundary 13 between the intermediate surface 10 and the slope 8 at the side opposite to the sealed fluid, a reverse screw section 11B is provided in such a way that the reverse screw section 11B does not reach the boundary 12 between the intermediate surface 10 and the slope 7 at the side of the sealed fluid, and both these reverse screw sections 11A and 11B are provided alternately on the circumferential surface. When the threadless regions 14 are provided alternately on the circumferential surface in this configuration, the oil seal 1 can have both a function for increasing the thickness of the oil film and a function for preventing the static leakage, and can thus have low torque and excellent sealing property. In addition, the former, i.e. the reverse screw section 11A reaches the boundary 12 between the intermediate surface 10 and the slope 7 at the side of the sealed fluid, and the latter, i.e. the reverse screw section 11B reaches the boundary 13 between the intermediate surface 10 and the slope 8 at the side opposite to the sealed fluid.

    [0029] In addition, the intermediate surface 10 is parallel to a center axis (not illustrated) of the oil seal 1 which is an annular body, or has a smaller sloping angle with respect to the center axis of the oil seal 1 than the sloping angle of the slope 7 at the side of the sealed fluid and the sloping angle of the slope 8 at the side opposite to the sealed fluid. Therefore, there are the following three kinds of examples which are useful for understanding the present invention of the intermediate surface 10 in a mounted state (when the shaft is inserted).
    1. (1) A cylindrical intermediate surface parallel to the center shaft of the oil seal 1, as illustrated in Fig. 5 (A).
    2. (2) A sloping (conical) intermediate surface having an angle θ1 at the side E opposite to the sealed fluid (the intermediate surface has an inner diameter size expanding from the side D of the sealed fluid to the side E opposite to the sealed fluid), as illustrated in Fig. 5 (B).
    3. (3) A sloping (conical) intermediate surface having an angle θ2 at the side D of the sealed fluid (the intermediate surface has an inner diameter size expanding from the side E opposite to the sealed fluid to the side D of the sealed fluid), as illustrated in Fig. 5 (C).


    [0030] In these cylindrical intermediate surfaces, the intermediate surface in (3) has following effectiveness.

    [0031] In case of (3), the intermediate surface 10 is a slope surface having the angle θ2 at the side D of the sealed fluid. Thus, the seal lip 6 slides on a line (the boundary 13) between the slope 8 at the side opposite to the sealed fluid and the intermediate surface 10. On the other hand, the line is a portion where the sealed fluid is gathered most by the pumping effect induced by the screw section 9 provided on the slope 8 at the side opposite to the sealed fluid and the pumping effect induced by the reverse screw section 11 provided on the intermediate surface 10. Therefore, since the seal lip 6 slides on the portion where the sealed fluid is gathered most, the thickness of the oil film of the sliding portion increases more than the thickness of the oil film in case of (1) or (2), and the oil seal 1 can thus have more excellent low torque characteristics.

    [0032] The magnitude of the sloping angle θ2 of the intermediate surface 10 to the side D of the sealed fluid in a mounted state is properly within a range of 0<θ2≤25 degrees, and more properly 0.1<θ2≤20 degrees.

    [0033] Further, the magnitude of the sloping angle θ1 of the intermediate surface 10 to the side E opposite to the sealed fluid in a mounted state is properly 0<θ1≤25 degrees. The magnitude of the sloping angle of the slope 7 at the side of the sealed fluid is properly 50±10 degrees, and the magnitude of the sloping angle of the slope 8 at the side opposite to the sealed fluid is properly 20±10 degrees.


    Claims

    1. An oil seal (1) comprising:

    a seal lip (6) in slidably close contact with a circumferential surface of a mating member such as an shaft;

    a slope (7) at the side of sealed fluid and a slope (8) at the side opposite to the sealed fluid, both of which are provided on the seal lip (6); and

    a screw section (9) provided on the slope (8) at the side opposite to the sealed fluid to perform a function of pushing back sealed fluid by a pumping effect induced at a time of rotation,

    wherein an intermediate surface (10) is provided between the slope (8) at the side of the sealed fluid and the slope at the side opposite to the sealed fluid, the intermediate surface (10) being in surface contact with the circumferential surface of the mating member along a predetermined axial direction width (L),

    characterized in that

    an oppositely threaded screw section (11) for performing a function of sucking the sealed fluid by a pumping effect induced at a time of rotation is provided on the intermediate surface (10), and

    the oppositely threaded screw section (11) provided on the intermediate surface (10) is provided in such a way that the oppositely threaded screw section (11) does not reach a boundary (13) between the intermediate surface (10) and the slope (8) at the side opposite to the sealed fluid,

    so that a threadless region (14) lying in the entire circumference between the screw section (11) and the boundary (13) and being in close contact with the circumferential surface of the mating member is provided.


     


    Ansprüche

    1. Öldichtung (1) mit:

    einer Dichtungslippe (6), die mit einer Umfangsfläche eines Gegenbauteils, wie zum Beispiel einer Welle, im verschiebbaren engen Kontakt ist;

    einer Schräge (7) an der Seite einer abgedichteten Flüssigkeit und einer Schräge (8) an der zu der abgedichteten Flüssigkeit entgegengesetzten Seite, die beide an der Dichtungslippe (6) vorgesehen sind; und

    einem Schraubenabschnitt (9), der an der Schräge (8) an der zu der abgedichteten Flüssigkeit entgegengesetzten Seite vorgesehen ist, um eine Funktion eines Zurückdrückens von abgedichteter Flüssigkeit durch eine Pumpenwirkung durchzuführen, die bei Rotation bewirkt wird,

    wobei eine Zwischenfläche (10) zwischen der Schräge (8) an der Seite der abgedichteten Flüssigkeit und der Schräge an der zu der abgedichteten Flüssigkeit entgegengesetzten Seite vorgesehen ist, wobei die Zwischenfläche (10) in Flächenkontakt mit der Umfangsfläche des Gegenbauteils entlang einer vorbestimmten Axialrichtungsbreite (L) ist,

    dadurch gekennzeichnet, dass

    ein Schraubenabschnitt (11) mit entgegengesetztem Gewinde zum Durchführen einer Funktion eines Saugens der abgedichteten Flüssigkeit durch eine Pumpwirkung, die bei Rotation bewirkt wird, an der Zwischenfläche (10) vorgesehen ist, und

    der Schraubenabschnitt (11) mit entgegengesetztem Gewinde, der an der Zwischenfläche (10) vorgesehen ist, derart vorgesehen ist, dass der Schraubenabschnitt (11) mit entgegengesetztem Gewinde eine Grenze (13) zwischen der Zwischenfläche (10) und der Schräge (8) an der zu der abgedichteten Flüssigkeit entgegengesetzten Seite nicht erreicht,

    sodass ein gewindeloses Gebiet (14) vorgesehen ist, das in dem gesamten Umfang zwischen dem Schraubenabschnitt (11) und der Grenze (13) liegt und im engen Kontakt mit der Umfangsfläche des Gegenbauteils ist.


     


    Revendications

    1. Joint d'étanchéité à l'huile (1) comprenant :

    une lèvre de joint d'étanchéité (6) en contact immédiat coulissant avec une surface circonférentielle d'un élément de couplage tel qu'un arbre ;

    une inclinaison (7) du côté du fluide scellé et une inclinaison (8) du côté opposé au fluide scellé, dont les deux sont prévues sur la lèvre de joint d'étanchéité (6) ; et

    une section de vis (9) prévue sur l'inclinaison (8) du côté opposé au fluide scellé afin de réaliser une fonction de repoussage de fluide scellé par un effet de pompage induit au moment de la rotation ;

    dans lequel une surface intermédiaire (10) est prévue entre l'inclinaison (8) du côté du fluide scellé et l'inclinaison du côté opposé au fluide scellé, la surface intermédiaire (10) étant en contact de surface avec la surface circonférentielle de l'élément de couplage le long d'une largeur dans la direction axiale prédéterminée (L),

    caractérisé en ce que :

    une section de vis (11) filetée à l'opposé pour réaliser une fonction d'aspiration du fluide scellé par un effet de pompage induit au moment de la rotation, est prévue sur la surface intermédiaire (10), et

    la section de vis (11) filetée à l'opposé prévue sur la surface intermédiaire (10), est prévue de sorte que la section de vis (11) filetée à l'opposé n'atteint pas une limite (13) entre la surface intermédiaire (10) et l'inclinaison (8) du côté opposé au fluide scellé,

    de sorte qu'une région sans filetage (14) se trouvant dans toute la circonférence entre la section de vis (11) et la limite (13) et étant en contact immédiat avec la surface circonférentielle de l'élément de couplage est prévue.


     




    Drawing

















    Cited references

    REFERENCES CITED IN THE DESCRIPTION



    This list of references cited by the applicant is for the reader's convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard.

    Patent documents cited in the description