DE102019217606A1 - Sealing device, in particular for a motor shaft - Google Patents

Abstract

Sealing device (1) which comprises a first annular shield (4) which can engage with a first stationary element (2) which carries an axially and radially projecting sealing lip (9), and a second annular shield (7) which also can engage a second rotating element (3), which is attached in a freewheeling manner with the first shield on the opposite side to the sealing lip (9) in order to define a labyrinth seal (19) of the static type therebetween, the second shield (7) with is provided with a plurality of projections (20) which project axially and which are on the opposite side to the sealing lip (9), which have a radial extension and are circumferentially spaced apart from one another by corresponding circumferential recesses (22) in order to form a helix (24 ), which defines a dynamic labyrinth seal (23), which is designed to follow a relative rotation of the shields (4, 7) to a fluid flow (25) generate that repels the external contaminants.

Description

Technical field of the invention

The present invention relates to a sealing device that can be inserted between two elements that perform a relative rotation. In particular, the invention relates to a sealing device for a motor shaft, which can be inserted between the rotating motor shaft and the stationary motor housing or body, which is formed by a base or an oil pan, in order to achieve a double sealing effect, i.e. both for the engine oil contained in the tub and against external contaminants (water, mud, dust, etc.).

State of the art

As is known, sealing devices on a motor shaft have the problem of protecting the sealing lip, which makes sliding contact with the side surface of the motor shaft, and which is intended to prevent the engine oil from seeping out and the ingress of external contaminants, which, if they come into direct contact with the sealing lip, the premature wear of which causes oil leaks.

An oil stop device is currently available on the market which is provided with a rubberized plastic insert which creates an additional labyrinth seal between the external environment, which contains a large amount of contaminants, and the oil side of the sealing lip. Is also from the US 5368314 a sealing device for high pressure pump shafts is known which comprises a contactless front seal between two elements of the sealing device which rotate relative to one another, which results from the formation of a gaseous pressure between the elements which rotate relative to one another, due to axially opposite recesses defined by grooves are that extend spirally in a radial direction.

The known sealing devices are not without drawbacks. The device in US 5368314 is extremely complex, costly and bulky and cannot be used for engine shafts of internal vehicle internal combustion engines.

Oil stoppers currently used in vehicle engines are instead reliable and compact, but are nevertheless unsuitable to prevent some contaminants from entering the labyrinth seal in the long term, particularly in critical operating conditions such as when used in off-road vehicles, and the like Reach sliding contact lip, which increases their natural wear. Furthermore, the production of rubberized plastic inserts is relatively expensive because it requires a double molding process.

Summary of the invention

The object of the present invention is therefore to overcome the disadvantages of the prior art and, in particular, to provide a reliable sealing device which is compact in size and is inexpensive, while at the same time increasing the sealing capacity of the device with regard to external contaminants and oil and in general the performance with regard to to improve the protection of the motor shaft assembly from contaminants compared to prior art solutions.

On the basis of the invention there is therefore provided a sealing device, in particular for a motor shaft, which has the characteristic features which are described in the appended claims.

Figure list

• 1 in schematischer Form eine perspektivische Dreiviertelvorderansicht der Dichtvorrichtung gemäß der Erfindung zeigt, die von der Seite gegenüber der betrachtet wird, die im Gebrauch dem Motoröl ausgesetzt ist, mit anderen Worten von der Seite betrachtet wird, die im Gebrauch in Richtung der äußeren Umgebung gerichtet ist;
• 2 eine entlang der Ebene II-II der 1 geschnittene Seitenansicht der Dichtvorrichtung zeigt, die zwischen zwei Elementen befestigt ist, die eine relative Rotation durchführen und die durch eine rotierende Motorwelle und eine stationäre Motorbasis (in schematischer Form und nur teilweise in gestrichelten Linien gezeigt) definiert ist;
• 3 in schematischer Form eine perspektivische Dreiviertelvorderansicht, das heißt von der Seite, die im Gebrauch in Richtung der äußeren Umgebung gerichtet ist, einer innovativen Komponente der Dichtvorrichtung gemäß 1 und 2 zeigt;
• 4 eine Querschnittsansicht entlang der Ebene IV-IV der 3 der gleichen Komponente ist;
• 5 eine Querschnittsansicht im größeren Maßstab eines Ausschnitts der Querschnittsansicht von 4 ist;
• 6, 7 und 8 in schematischer Form und im größeren Maßstab entsprechende Details der Dichtvorrichtung gemäß den 1 und 2 zeigen; und
• 9 in schematischer Form eine perspektivische und radial geschnittene Dreiviertelvorderansicht einer möglichen Variante der Dichtvorrichtung gemäß 1 zeigt.

The invention will now be described with reference to the accompanying drawings, which show two non-limiting examples of embodiments thereof, in which:

• 1 shows in schematic form a three-quarter perspective front view of the sealing device according to the invention, viewed from the side opposite to that which is exposed to the engine oil in use, in other words viewed from the side which in use is directed towards the external environment;
• 2nd one along level II-II of the 1 shows a sectional side view of the sealing device, which is fixed between two elements which perform a relative rotation and which is defined by a rotating motor shaft and a stationary motor base (shown in schematic form and only partially shown in broken lines);
• 3rd in schematic form, a perspective three-quarter front view, that is, from the side, which in use is directed towards the external environment, according to an innovative component of the sealing device 1 and 2nd shows;
• 4th a cross-sectional view along the plane IV-IV the 3rd is the same component;
• 5 a cross-sectional view on a larger scale of a section of the cross-sectional view of 4th is;
• 6 , 7 and 8th in schematic form and on a larger scale corresponding details of the sealing device according to the 1 and 2nd demonstrate; and
• 9 in schematic form, a perspective and radially cut three-quarter front view of a possible variant of the sealing device according to 1 shows.

Detailed description

With respect to the 1 and 2nd denotes in them 1 a sealing device in its entirety, which is between a first element 2nd , which is stationary, and a rotating second element 3rd can be used, the elements only in schematic form and in dashed lines in 2nd are shown.

In particular, there is the stationary element 2nd in the examples shown, from a base of an internal combustion engine of a vehicle, which is known and which is not shown for the sake of simplicity, while the rotating element is formed by a motor shaft which extends axially from the base 2nd protrudes. The sealing device 1 is radial between the elements 2nd and 3rd used, on the one hand, the lubricating oil, which is necessary for the operation of the engine, in the base 2nd and on the other hand to prevent the entry of any contaminants from the outside, such as water, dust and mud, from the outside in the environment in which the vehicle is moving.

The sealing device 1 comprises a first annular shield 4th that with a substantially cylindrical sleeve portion 5 is provided, which is set up in a known manner fixedly with the first element 2nd engage, and a flange portion 6 which protrudes radially from the sleeve portion 5 in the direction of an axis of symmetry A of the sleeve section 5 extends.

The sealing device also comprises a second annular shield 7 which is adapted to engage firmly with the second element and which, as can be seen below, is attached to the first shield in a freewheeling manner, and an annular sealing ring 8th that with at least a first annular sealing lip 9 is provided, which projects axially and radially from the flange portion 6 in the direction of the axis of symmetry A and on the opposite side to the second shield 7 extends.

The ring-shaped sealing ring 8th is made in a known manner according to a process called vulcanized gluing, from an elastomeric material and in a known manner by means of injection molding or preferably compression molding on a metal frame 10th formed, which consists of a cut and folded sheet metal around the sleeve portion 5 and the flange section 6 the shield 4th to form as a whole.

The ring-shaped sealing lip 9 is made of the same elastomeric material as the sealing ring 8th formed and integrally molded with it as one piece. The sealing lip 9 is also designed to engage and in a fluid-tight manner with the second member or motor shaft 3rd interact as schematically in 2nd is shown with the lip 9 is shown in an undeformed configuration. A contact pressure between the lip 9 and the wave 3rd the lip is sufficient to ensure a substantially constant sealing effect 9 with an annular spring 11 provided that they use against the shaft 3rd presses.

Furthermore, the sealing ring 8th also integrally as one piece with a second annular lip 12 provided, which project radially and axially from the sleeve section 6 in a direction opposite to and substantially symmetrical with the sealing lip 9 extends with which it forms a V in radial cross section, the tip in the direction of the sleeve portion 5 is directed. The lip 12 is designed with the shaft 3rd interact, but do not make contact to provide a labyrinth seal that seals the lip 9 protects. A page 13 the lip 9 going towards the lip 12 is preferred, with known grooves 14 provided to improve the sealing effect.

Around the shields 4th and 7 to enable it to engage with each other in a free running manner has the annular shield 7 a radially outer peripheral edge 15 with axial and radial play in an annular seat 16 ( 2nd ) of the sleeve section 5 intervenes.

The ring-shaped seat 16 is formed in a radial cross section in the manner of a U, in the direction of the axis of symmetry A and is in one non-limiting example shown by one end 18th of the sleeve section 5 the first shield 4th limited, which is on the opposite side to the first annular sealing lip 9 located and folded in an asymmetrical U shape. The radially outer peripheral edge 15 the second shield 7 and the U-shaped annular seat 16 the first shield 4th , namely the U-folded end 18th of the sleeve section 5 It defines a first labyrinth seal between them 19th of a static type, since they are capable of creating a tortuous path for any external contaminants that try to pass through the shield 7 towards the first annular sealing lip 9 to get. The labyrinth seal 19th is therefore a labyrinth seal of the conventional type, namely a non-contact seal, which in any case prevents the passage of external contaminants.

According to the invention, the second shield is on the opposite side of the flange section 6 the first shield with several axially projecting cantilevers 20th provided in the to the first annular sealing lip 9 opposite direction are directed.

The cantilevers 20th have a radial extent in the sense that they extend radially outward in the opposite direction to the axis A from a radially inner annular section 21st the shield 7 extend to a point that is near the edge 15 located, but remain at a predetermined distance from it.

The cantilevers 20th are circumferentially in a ring on the second shield 7 arranged circumferentially spaced from one another, so that a plurality of circumferential recesses 22 , each between a pair of immediately adjacent cantilevers 20th are defined, separate them.

According to the invention, the cantilevers 20th and the corresponding extensive recesses 22 that separate them, if necessary, together with the shield 4th , a second labyrinth seal 23 to define the dynamic type in line with the first labyrinth seal 19th and on one to the first annular sealing lip 9 opposite side is arranged.

In principle, the second labyrinth seal is 23 Defined as a "labyrinth" type because it creates a non-contact barrier that prevents the entry of external contaminants in the manner of a conventional labyrinth seal, such as the seal 19th , prevents; however, unlike the latter, the dynamic labyrinth seal creates 23 not a winding path, but is formed by the fact that the overhangs 20th and the corresponding extensive recesses 22 that separate them, a helix 24th ( 3rd and 4th ) which is suitable for the relative rotation of the first shield 4th and the second shield 7 following a fluid stream 25th (schematically by the arrows in 2nd displayed) to generate the external contaminants from the shields 4th and 7 rejects.

To achieve the dynamic “labyrinth” effect described above, each cantilever is 20th radially outwards through a first active surface 26 and through a second active area 27th limited, which between them an angle different from 180 ° ( 6 ) and which fit together around a vertex 28 to generate a radially outer end 29 every cantilever 20th defined that radially from the edge 15 is spaced.

The cantilevers 20th have the same radial extent and their ends 29 therefore all lie on a circumference or all go through a circumference with a radius R (not shown for simplicity).

Regarding 6 form for each cantilever 20th the first active area 26 along with a line p perpendicular to the radius R the shield 7 that describes the scope on which all ends 29 of the overhangs 20th lie and through the vertex 28 go through a first angle α while the second active areas 27th together with the same line p perpendicular to the radius R by the apex 28 goes through a second angle β form.

According to one aspect of the invention, the first angle α be less than 75 ° and the second angle β should be larger than 35 °. The first angle is preferred α between 55 ° and 65 ° and the second angle β is between 40 ° and 55 °.

Furthermore, according to a preferred embodiment of the invention, at least one of the first and second surfaces 26 , 27th or both curved and have a concavity that is directed radially outwards. In particular, the area 27th a profile that extends in the manner of a helix that defines a spiral section.

The second shield is more general 7 formed in the manner of a flange and the projections 20th are on an annular front surface 30th the second shield 7 formed the same on the opposite side of the first shield 4th limited.

The cantilevers 20th extend over or are in alignment with the radially inner annular portion 21st the shield 7 , which also has a radially inner annular portion of the surface 30th Are defined.

The annular section 21st is preferably step-shaped and forms on the annular surface 30th a cylindrical section 31 with an outside diameter that is smaller than that of the edge 15 .

The vertex 28 every cantilever 20th is at an angle with respect to the axis of symmetry A ( 7 ) arranged and forms with a line c perpendicular to the annular front surface 30th the shield 7 , the vertical line c parallel to the axis of symmetry A is a third angle δ, which is on the opposite side to the axis of symmetry A located between 5 ° and 11 °, the angle being for the purpose of improving the fluid flow 25th to repel external contaminants, especially to promote dispersion thereof, away from the shields 4th and 7 Has.

Finally, the extensive recesses 22 along a radial direction, a width in the circumferential direction that gradually changes in the direction away from the axis of symmetry A elevated.

Now with reference to the 9 shows this one possible variant 100 the sealing device described above 1 . Details similar or identical to those that have already been described are denoted by the same reference numerals for the sake of simplicity.

The sealing device 100 includes a shield 4th , which is identical to that already described and which has an annular sealing ring 8th is provided, and a second annular shield 70 that are different from the shield described above 7 due to the shape of the overhangs 20th differs by the overhangs 200 have been replaced.

The cantilevers 200 are defined by blades that are relative to the axis of symmetry A and have a substantially spiral profile along a radial direction that develops radially outward. The shovels 200 are axially projecting on a radially outer annular section 32 the annular front surface 30th the shield 70 formed, the latter on the opposite side to the first shield 4th restrict.

The shovels 200 also extend radially projecting from the step-shaped annular portion 21st the annular front surface 30th and the shield itself and define extensive recesses between them 220 that extend so that they are radial between a radially outer free end 29 the shovels 200 (more generally the radially outer end of the cantilevers 200 defined) and the step-shaped annular portion 21st the second shield 70 are arranged.

The shovels 200 have adjacent active areas 260 and 270 that the apex 28 define and the radially outer ends 29 of the overhangs 200 restrict.

The critical values of the orders of magnitude of the angles α and β that with the line perpendicular to the radius R are formed, as shown above, are also on the active areas 260 and 270 , only applicable to the described embodiment.

However, it is possible to use the blades 200 to design with a different shape, such as blades, which are formed with thin flanges, which are twisted in a direction to their radial expansion, the active surfaces 260 have a small area.

Finally, in both described embodiments 1 and 100 the second shield 7 or 70 preferably along its radially outer peripheral edge 15 with radial deflectors 33 to improve fluid flow 25th provided that the external impurities (for the sake of simplicity only on the sealing device 1 shown).

The radial deflectors 33 consist of an axial annular shoulder 34 ( 5 and 7 ) along the radially outer peripheral edge 15 are formed and radially inwards and in the direction of the projections 20th (200 in the case of the sealing device 100 ) by several adjacent teeth 35 ( 8th ) are limited, which have a sawtooth profile in the circumferential direction.

The teeth 35 are designed such that the radially outer end 29 of any overhang 20th (200 in the case of the device 100 ) a bend 71 opposite, the two adjacent teeth 35 the annular shoulder 34 separates to eliminate the fluid flow 25th to promote externally.

From the above description it is clear that while the lip 9 A common radial sealing lip is used for the specific application on motor shafts 3rd was optimized, and the one oil seal regardless of the speed of rotation of the shaft 3rd ensures the shielding 7 (or 70), which is made entirely of synthetic resin in one piece by a single molding, physically with the shaft 3rd remains connected, and with respect to the shield 4th that are physically related to the engine base 2nd connected and therefore stationary, rotates while the shaft 3rd rotates.

For this purpose, the radially inner section 21st through a radially inner edge 72 limited, which is designed with a slight engagement in the shaft or the rotating element 3rd intervene (for example with an h6 / H7 fit according to the tolerance system for a basic shaft).

In use causes the shaft 3rd during the rotation also the rotation of the plastic insert or the shield 7 (or 70). The Cantilevers 20th or the shovels 200 covering the outer part of the plastic shield 7 or 70 form, create a fluid-dynamic pumping action that removes any contamination particles (dust, metal particles, etc.) far from the sealing ring 8th pump before they seal the labyrinth 19th the conventional way.

In this way, when the external contamination is in contact with the helix 24th comes, they rejected, increasing the risk of contamination in the sealing maze 19th penetrates, is reduced.

The shape of the helix 24th , namely the overhangs 20th / 200 and the recesses 22 / 220 that they form are designed to repel the contaminant towards the outer diameter of the shield 7 / 70 due to the distance between the blades 200 / projections 20 through the recesses 22 / 220 are defined, which increase their circumferential width or extension from the inside towards the outside, whereby the maximum outer circumferential speed is used.

In fact, due to the geometry described and the values chosen for the angles α and β the active area 26 or 260 parallel to the result of the vector arrangement between the peripheral speed vector of the edge 15 the shield 7 / 70 and the centrifugal force vector, thus resulting in the maximum possible flow rate for the fluid flow 25th can be obtained.

All of the objects of the invention are therefore achieved.

QUOTES INCLUDE IN THE DESCRIPTION

This list of documents listed by the applicant has been generated automatically and is only included for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• US 5368314 [0003,0004]

Claims (10)

Sealing device (1; 100) which can be used between a first element (2) which is stationary and a second element (3) which rotates, in particular between a base and a motor shaft of an internal combustion engine, and which comprises: - A first annular shield (4), which is provided with a sleeve section (5) which is designed to rigidly engage with the first element, and with a flange section (6) which projects radially from the sleeve section in the direction of an axis of symmetry (A) the sleeve portion extends; - a second ring-shaped shield (7; 70), which is designed to rigidly engage with the second element, and which is freely connected to the first shield (4); and - an annular sealing ring (8) which is provided with at least one first annular sealing lip (9) which projects axially and radially from the flange section (6) in the direction of the axis of symmetry (A) and on the opposite side to the second shield (7; 70) extends and is designed to interact with the second element (3) by means of an engagement and in a fluid-tight manner; wherein the first and second shields (4, 7; 70) define between them a first labyrinth seal (19) of the static type, which is adapted to form a tortuous path for the passage of any external contaminants directed towards the first annular sealing lip are to generate; characterized in that: - the second shield (7; 70) on the opposite side to the flange portion (6) of the first shield is provided with a plurality of projections (20; 200) which are axially projecting and in the opposite direction to the first annular Sealing lip are directed, the projections have a radial expansion; - The projections (20; 200) are arranged circumferentially in a ring around the second shield, are circumferentially spaced apart from one another to be separated by a plurality of circumferential recesses (22; 220), which are each defined between a pair of immediately adjacent projections; - The projections (20; 200) and the respective circumferential recesses (22; 220) which separate them are designed to define a second labyrinth seal (23) in series with the first labyrinth seal (19) and on the opposite one Side to the first annular sealing lip (9) is arranged; - The second labyrinth seal (23) is of a dynamic type, the projections and the corresponding circumferential recesses which separate them forming a helix (24) which is designed to follow a relative rotation of the first and the second shielding a fluid flow (25) which repels the external contaminants from the first and second shields. Sealing device according to Claim 1 , characterized in that the second annular shield (7; 70) has a radially outer peripheral edge (15) which engages with axial and radial play within an annular seat (16) of the sleeve spacing (5), which has a radial cross section in the Type of U, which is directed in the direction of the axis of symmetry (A) is formed; the radially outer peripheral edge (15) of the second shield and the U-shaped annular seat of the first shield defining between them the first labyrinth seal (19) of the static type; wherein the U-shaped annular seat (16) is defined by a first end (18) of the sleeve portion of the first shield that is on the opposite side to the first annular sealing lip (9). Sealing device according to Claim 1 or 2nd , characterized in that each projection (20; 200) is delimited radially outwards by a first active surface (26; 260) and a second active surface (27; 270) which form an angle different from one another between 180 ° and which join together to create a vertex (28) defining a radially outer end (29) of each projection. Sealing device according to Claim 3 , characterized in that the first active surface (26; 260) and the second active surface (27; 270) each have a same line (p) passing through the vertex edge (28) that joins them, perpendicular to one Radius (R) of the second shield (7; 70), a first angle (α) and a second angle (β), the first angle (α) being less than 75 °; and the second angle (β) is greater than 35 °. Sealing device according to Claim 4 , characterized in that the first angle (α) is between 55 ° and 65 °; and that the second angle (β) is between 40 ° and 55 °. Sealing device according to one of the Claims 3 to 5 , characterized in that at least one or both of the first and second surfaces (26; 260, 27; 270) are curved and have a concavity which is directed radially outwards. Sealing device according to one of the Claims 3 to 6 characterized in that the second shield (7; 70) is flange-shaped, the projections being formed on an annular front surface (30) of the second shield, the latter delimiting on the opposite side to the first shield; the apex edge (28) of each projection being arranged at an angle with respect to the axis of symmetry (A) and with a line (c) perpendicular to the annular front surface (30) of the second shield, parallel to the axis of symmetry, forms a third angle (δ), which is directed on the opposite side to the axis of symmetry and is between 5 ° and 11 °, this improving the fluid flow which repels the external contaminants. Sealing device (100) according to any one of the preceding claims, characterized in that the projections are defined with blades (200) which, with respect to the axis of symmetry (A) and along a radial direction, have a substantially spiral-like profile which extends radially outwards developed; the blades (200) being axially cantilevered on a first outer annular portion (32) of an annular front surface (30) of the second shield (70), the latter being on the opposite side to the first shield (4), the Blades (200) also project radially from a second stepped annular portion (21) of the annular front surface of the second shield and define between them the circumferential recesses (220) which extend until they extend radially between a radially outer free end (29) the blades and the second step-shaped annular portion (21) of the annular front surface of the second shield. Sealing device according to one of the preceding claims, characterized in that the circumferential recesses (22; 220) along a radial direction have a width in the circumferential direction which gradually increases in the direction away from the axis of symmetry. Sealing device according to one of the preceding claims, characterized in that the second shield (7; 70) is provided on its radial outer peripheral edge (15) with radial deflectors (33) for improving the fluid flow which repel the external impurities; wherein the radial deflectors (33) are formed by an axially annular shoulder (34), which are formed along the radially outer peripheral edge (15) and radially inwards and in the direction of the projections by a plurality of adjacent teeth (35) with a sawtooth profile in one Circumferential direction are limited, with a radially outer end (29) facing each projection of a bend separating two adjacent teeth (35) of the annular shoulder.

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