Sealing arrangement

Abstract

Sealing arrangement for a ball joint (1) of a chassis with: a ball pin (3) associated with the ball joint (1), which comprises a ball part (4) and a pin part (14) projecting therefrom and is mounted by means of the ball part (4) in a rotatable and pivotable manner relative to a joint housing (2), and a sealing bellows (5) which, for sealing the ball joint (1) from the environment, is mounted with a housing-side edge section (6) relative to the joint housing (2) and with a pin-side edge section (7) relative to the ball pin (3), wherein the ball pin (3) is assigned a receiving area (8; 18) which the pin-side edge section (7) of the sealing bellows (5) contacts at three circumferential contact surfaces (9, 10, 11; 19, 20, 21), of which an axial contact surface (10; 20) simultaneously borders on an inner radial contact surface (9; 19) and on an outer radial contact surface (11; 21), characterized in that the outer radial contact surface (11; 21) encloses an obtuse angle with the axial contact surface (10; 20) for absorbing both radial and axial sealing forces.

Description

The invention relates to a sealing arrangement for a ball joint of a chassis according to the preamble of claim 1 and to a raceway for use on such a sealing arrangement according to claim 11.Such a sealing arrangement is known from CH 465 971 A. In this case, a radial flange of a bearing ring has three circumferential contact surfaces, wherein a radial outer contact surface is inclined radially inward.U.S. Pat. No. 6,357,956 B1 discloses a bearing ring having a surface inclined radially outwards, wherein a sealing bellows is pressed by means of a spring ring to the radially inner side.Ball joints are generally known from vehicle construction. These are used in particular in the construction of a chassis in order to connect chassis components to one another in a articulated manner. In this context, reference is made quite generally by way of example to the laid-open specification DE 100 05 979 A1, which describes a ball joint. As essential structural elements, a ball joint always comprises a joint housing and a ball stud. The ball stud usually consists of a ball part and a stud part projecting therefrom. The ball part is received by the joint housing, so that the ball stud is mounted rotatably and pivotably with respect to the joint housing.To ensure reliable and permanent operation, it is necessary to protect the joint interior from moisture and / or contaminants. Ball joints used in vehicle construction are therefore equipped with a sealing system which usually comprises a sealing bellows which surrounds the ball stud in regions and is installed with one end on the housing side and with an opposite end on the stud side, in order in this way to seal the interior of the joint from the external environment and thus to prevent entry of moisture and / or contaminants.For the connection of a pin-side edge section of the sealing bellows, various technical solutions are known from the prior art. For example, known conventional races have a protruding portion toward the joint inner side. An integrated clamping ring hardly permits any expansion (in contrast to the slotted round wire ring). Therefore, although these bellows can realize higher contact pressures (=higher tightness), they cannot be mounted on a conventional raceway (or over its protruding section).Referring now to Figures 1 and 2 of the drawings, there are shown two different conventional seal assemblies. In the seal arrangement shown in FIG. 1, a substantially L-shaped raceway 32 is used, with respect to its cross section, which abuts with one leg on the ball stud 34 and with one leg on the chassis component 33. The pin-side edge section 30 of the sealing bellows touches the two legs of the raceway 32 in a plurality of regions, a round wire clamping ring 31 arranged on the outer circumference of the pin-side edge section 30 serves for securing and applying the sealing forces. When the raceway is pushed onto the ball stud, the stud-side edge section of the sealing bellows must be pulled over a radially outwardly projecting section of the raceway even with the clamping element pre-assembled; in addition, a clamping element engaging from the outside (round wire clamping ring 31) is required to be subsequently installed in order to apply the necessary sealing forces. In addition, many elastomers tend to stiffen under minus temperatures. Therefore, the pin-side radial sealing light lips (with the pin bent out) on the pulling side can lose contact with the sealing surface of the pin. This results in a leak in the joint.In a sealing arrangement which is likewise known from the prior art and is shown in FIG. 2, the pin-side edge section 40 of the sealing bellows bears directly, i.e. without the interposition of a raceway, radially on the inside against the ball pin 44 and axially against the chassis component 43. A clamping ring 41 for applying sealing forces is integrated into the material of the pin-side edge section. A disadvantage of this design is that the sealing effect with respect to the chassis component 43 is relatively low, in particular in the radially outer region, and practically only dust rejection takes place here because of the sealing forces that are to be applied only slightly in this region. Overall, the sealing effect is subject to relatively great aging effects of the rubber of the sealing bellows, so that the latter decreases in an undesired manner with increasing operating duration.It is an object of the present invention to provide a sealing arrangement of the type mentioned at the beginning which can be mounted in a simple and reliable manner and which has a long-lasting high sealing effect over the service life.The object is achieved by a sealing arrangement according to claim 1, which is a sealing arrangement for a ball joint of a chassis, comprising a ball stud assigned to the ball joint, which comprises a ball joint and a stud part projecting therefrom and is mounted rotatably and pivotably with respect to a joint housing by means of the ball part, and a sealing bellows, which is mounted with a housing-side edge section with respect to the joint housing and with a stud-side edge section with respect to the ball stud for sealing the ball joint with respect to the environment. According to the invention, the sealing arrangement is characterized in that the ball stud is assigned a receiving region which the stud-side edge section of the sealing bellows touches on three circumferential contact surfaces, of which an axial contact surface simultaneously adjoins an inner radial contact surface and an outer radial contact surface.It was first recognized that the sealing effect of the sealing arrangement can be advantageously increased in that the pin-side edge section of the sealing bellows is supported not only on two contact surfaces-as is known in the previously described prior art-but rather better on three contact surfaces arranged in a special manner. According to the invention, the three circumferential contact surfaces are an axial contact surface and two radial contact surfaces. An axial contact surface is understood to be a contact surface which is in contact with the pin-side edge section of the sealing bellows in order to achieve an axial sealing effect. For this purpose, the axial contact surface expediently extends in a substantially radial direction with respect to a central axis of the ball stud. According to the invention, the axial contact surface is simultaneously adjoined by an inner radial contact surface and an outer radial contact surface. An inner radial contact surface is understood to mean a contact surface which is in contact with the housing-side edge section of the sealing bellows in order to achieve an inner radial sealing effect with respect to the sealing bellows. For this purpose, the inner radial contact surface, with respect to the center axis of the ball stud, extends within the housing-side edge section of the sealing bellows, i.e. is surrounded circumferentially by the latter. To absorb radial sealing forces, the inner radial contact surface extends substantially in the axial direction with respect to the central axis of the ball stud. The outer radial contact surface is a contact surface which is in contact with the pin-side edge section of the sealing bellows in order to achieve a radial sealing effect at least partially. In contrast to the inner radial contact surface, the outer radial contact surface serves at least partially to absorb sealing forces directed radially outwards, for which purpose the outer radial contact surface runs radially outside at least part of the housing-side edge section with respect to the central axis of the ball stud.The sealing arrangement according to the invention ensures a specific sealing of the pin-side edge section of the sealing bellows both in the radial and in the axial direction. By the cooperation of the pin-side edge section with three differently oriented contact surfaces of the receiving region assigned to the ball pin, a particularly effective sealing system is created by the multiple sealing mechanisms, wherein, due to the presence of the outer radial contact surface, not only is an improved pre-sealing effect achieved, but also losses of the contact pressure due to aging phenomena of the material of the sealing bellows can be compensated. Due to the at least partially inwardly directed radial contact force due to the outer radial contact surface, the sealing contact between the sealing bellows and the receiving region can be maintained at any rate even if parts of the axial contact force are lost. The sealing arrangement thus has a long-lasting sealing effect.Expediently, the pin-side edge section of the sealing bellows directly contacts the three contact surfaces of the receiving region, i.e. without the interposition of further structural elements.A constructionally advantageous configuration of the sealing arrangement results in the contact surfaces of the receiving region being arranged approximately J-shaped relative to one another in cross section, wherein the inner radial contact surface forms the long limb of the "J", the outer radial contact surface forms the short limb "J" and the axial contact surface forms a connecting section of these limbs. The configuration described in this way offers the advantage of simple assembly, relatively great freedom of movement of the sealing bellows, achieving a high sealing effect and reliable function. In a J-shaped configuration, the raceway encloses the pin-side sealing region of the bellows for the most part, whereby a so-called box design is achieved. The reaction forces of the outer radial sealing lip hold the plug-side sealing system in the intended position, in particular in the event of a tensile stress caused by full deflection. The loss of contact of the bellows with the sealing surface is prevented. In addition, the short leg of the "J" shields the pin-side sealing labyrinth, so that water can more difficult enter the sealing system.As an alternative to a J-shaped arrangement of the contact surfaces, a U-shaped arrangement with respect to one another is conceivable, which would differ from a J-shaped arrangement in that the outer radial contact surface had approximately the same length as the inner radial contact surface.The sealing arrangement can be advantageously designed in that the outer radial contact surface is designed to absorb both radial and axial sealing forces. The alignment of the outer radial contact surface has an influence on which types (radial and / or axial) of sealing forces can be absorbed by the latter.In order that radial as well as axial sealing forces can be absorbed at the same time with the outer radial contact surface, an advantageous further development of the seal arrangement provides that the outer radial contact surface encloses an obtuse angle with respect to the axial contact surface, i.e. an angle lying between 90 and 180 degrees.In vehicle technology, ball joints which have a sealing arrangement as described here are used, in particular, for the articulated connection of two chassis components. Accordingly, in the sealing arrangement described here, the ball stud is expediently connected to a chassis component. The chassis component can be, for example, a link, wheel carrier, etc.For connecting the ball stud to the vehicle component, the stud part expediently projects partially into a recess formed on the chassis component, in particular a passage, in order to be received in it in a form-fitting manner. In a manner known per se, the pin part has a conical course at least in regions for this purpose, wherein the recess formed on the chassis component has a conicity complementary thereto, so that a positive connection between these components is possible.For applying the pressing forces required for the sealing effect, an advantageous further development of the sealing arrangement provides that a clamping ring is integrated in the material of the pin-side edge section of the sealing bellows. By integrating a clamping ring, no separate assembly step for applying a clamping ring is required during the assembly of the sealing arrangement, which represents a simplification of the production process.The receiving region assigned to the ball stud with the three circumferential contact surfaces can be designed in different ways. From a manufacturing point of view, it is expedient that the receiving region is formed on a raceway mounted with respect to the ball stud. In this case, the receiving region is thus provided by a separate component in the form of a raceway. It is advantageous in this respect that the friction surfaces between the sealing bellows and the receiving region thus consist exclusively between the sealing bellows and a single component, namely the raceway. The surface condition in this case is thus independent of that of the ball stud and the chassis component. In other words, a complicated surface treatment of the ball stud and / or of the chassis component in the region of the contact surfaces is not necessary in this case, since these are formed on the raceway. The raceway can in turn be produced as a relatively cost-effective one-piece sheet metal form.As an alternative to a configuration of the receiving region on a raceway, it is conceivable for the receiving region to be formed jointly by contact surfaces formed on the ball stud and on the chassis component. In this case, the three circumferential contact surfaces provided according to the invention are therefore formed directly on the ball stud and on the chassis component. Such a configuration offers the advantage that without additional component a receiving region for the pin-side edge section of the sealing bellows is created. A shaping required for this can be carried out in different ways.In particular, the contact surfaces formed on the chassis component can be produced at least partially by machining.The invention further relates to a race for use on a seal assembly as described in claims 1 to 9. The raceway is characterized by three circumferential contact surfaces, of which an axial contact surface simultaneously adjoins an inner radial contact surface and an outer radial contact surface.As already mentioned above, an advantageous embodiment provides that the raceway is produced as a one-piece sheet metal formed part. Preferably, the race has an approximately J-shaped cross-sectional profile. Alternatively, it is conceivable for the raceway to have an approximately U-shaped cross-sectional profile.In a particularly preferred embodiment of the raceway with an approximately J-shaped cross-sectional profile, it preferably comprises an inner section forming the long leg of the "J", an outer section forming the short leg of the "J", and an intermediate section connecting the latter.Expediently, the inner section of the raceway is designed for bearing against an outer surface of the ball stud, in particular its stud part, and the intermediate section is designed for bearing against the chassis component. The raceway can thus advantageously come to bear simultaneously with the journal part and the chassis component. The invention is explained in more detail below with reference to a drawing which reproduces two exemplary embodiments of the invention. This also results in further advantageous effects of the invention. The figures show: FIG. 1 shows a conventional sealing arrangement according to the prior art in a detailed view, which is explained within the scope of the introduction to the description, FIG. 2 shows a further conventional sealing arrangement according to the prior art in a detailed view, which is explained within the scope of the introduction to the description, FIG. 3 shows a ball joint in schematic sectional illustration, which is provided with a sealing arrangement according to a first exemplary embodiment of the invention, FIG. 4 shows a detailed view of the detail designated by the letter "A" in FIG. 3, FIG. 5 shows a detailed view of a sealing arrangement according to a second exemplary embodiment of the invention.FIG. 3 shows a ball joint 1, which is suitable in particular for use on the chassis of a passenger vehicle or commercial vehicle. The ball joint 1 is equipped with a sealing arrangement according to the invention according to the first exemplary embodiment of the invention. The ball joint 1 has a ball stud 3 which comprises a ball part 4 and a stud part 14 projecting therefrom. By means of the ball part 4, the ball stud 3 is mounted rotatably and pivotably with respect to a joint housing 2 in a manner known per se. The ball stud 3 can thus be rotated about a central axis 26 and can be pivoted about a central point 27 of the ball part 4 relative to the joint housing 2.To seal the ball joint 1 from the environment, the ball joint 1 is assigned a sealing bellows 5 which surrounds the ball stud 3 in regions. The sealing bellows 5 is a hose-like element consisting essentially of elastomer material, wherein the sealing bellows 5 is mounted with a housing-side edge section 6 opposite the joint housing 2 and with a pin-side edge section 7 opposite the ball pin 3. Due to the inherently flexible material of the sealing bellows and its outwardly curved course, the sealing bellows 5 ensures that the ball stud 3 can perform operational swivel movements about the center point 27 with respect to the joint housing 2, but at the same time prevents contaminants and / or moisture from entering the interior of the joint.The ball joint 1 shown in FIG. 3 is equipped with a specially designed sealing arrangement, which is explained below with reference to FIG. 4, which shows the detail designated by the letter "A" in FIG. 3 in an enlarged view. As can be seen from FIG. 4, a raceway 13 is arranged on the pin part 14 (associated with the ball pin 3). The raceway 13 is a sheet metal formed part produced in one piece, which circumferentially surrounds the ball stud 3 in the region of the stud part 14 and bears with an inner portion 23 against an outer surface of the stud part 14. The raceway 13 has an approximately J-shaped profile in cross section, comprising an inner portion 23 forming the long leg of the "J", an outer portion 25 forming the short leg of the "J", and an intermediate portion 24 connecting them.As can be seen from FIG. 4, an outer surface of the intermediate section 24 lies flat against the chassis component 12. The chassis component 12 is, for example, a wheel carrier, wherein the chassis component 12 has a conical passage 15 (compare. FIG. 3 ) is provided, wherein the pin part 14 of the ball pin 3 for connecting the ball pin 3 to the chassis component 12 partially protrudes into this passage 15 in order to be received by it in a form-fitting manner. By means of fastening means not shown here, the ball stud 3 is axially braced with the chassis component 12, so that a force-fit and form-fit connection is produced between these components due to the conicity of the passage 15 and stud part 14.On the raceway 13, a receiving region 8 is formed, which serves for receiving and mounting the pin-side edge section 7 of the sealing bellows 5. Due to the special configuration of the raceway 13 and of the journal-side edge section 7, the journal-side edge section 7 contacts the raceway 13 at three circumferential contact surfaces 9, 10, 11 In particular, this is an axial contact surface 10 which simultaneously adjoins an inner radial contact surface 9 and an outer radial contact surface 11. The pin-side edge section 7 of the sealing bellows 5 directly contacts these three contact surfaces 9, 10, 11 of the receiving region 8 of the raceway 13. Due to the configuration of the raceway 13, the contact surfaces 9, 10, 11 of the receiving region 8 are arranged approximately J-shaped with respect to one another in cross section. The inner radial contact surface 9 forms the long leg of the "J", the outer radial contact surface 11 forms the short leg of the "J", and the axial contact surface 10 forms a connecting section of these legs.On the journal-side edge section 7 of the sealing bellows 5, a plurality of sealing lips 17, 18, 22 are formed, via which the sealing bellows 5 is in contact with the contact surfaces 9, 10, 11 formed on the raceway 13. The journal-side edge section 7 of the sealing bellows 5 contacts the inner radial contact surface 9 in the exemplary embodiment shown via three sealing lips 17 spaced apart from one another in the axial direction. Furthermore, the journal-side edge section 7 contacts the axial contact surface 10 of the raceway 13 via an axial sealing lip 22.While the axial contact surface 10 serves to absorb sealing forces acting in the axial direction and the inner radial contact surface 9 serves to absorb sealing forces acting in the radial direction, the outer radial contact surface 11 is designed such that it can absorb both radial and axial sealing forces. For this purpose, the outer radial contact surface 11 encloses an obtuse angle with respect to the axial contact surface 10, i.e. an angle lying between 90 and 180 degrees. In the contact region of the outer sealing lip 18 with respect to the outer radial contact surface 11, a sealing thus takes place, in which radial and axial sealing forces occur in combination. The outer sealing lip 18 can therefore function as a real sealing lip and assume a pre-sealing function which is essential for the longevity of the sealing arrangement.In the sealing arrangement of the first exemplary embodiment shown, a clamping ring 16 is integrated into the material of the pin-side edge section 7 of the sealing bellows 5. The shape of the raceway 13 contributes to simplified assembly of the sealing bellows with integrated clamping ring 16 on the raceway 13, since joining in the axial direction is possible without adverse effects. In addition, the J-shaped cross-sectional profile of the raceway prevents the raceway from folding over during assembly due to its increased dimensional stability.In the embodiment shown in FIG. 4, the ball stud 3 has a conical stud part 14. It should be noted that, in contrast thereto, the invention can also be realized on a ball stud with a cylindrical stud part. In this case, it is possible, but not absolutely necessary, for the raceway to contact the chassis component. However, it is also conceivable for a gap to be formed between the raceway and the chassis component.FIG. 5 shows a sealing arrangement according to a second exemplary embodiment of the invention. As can be seen from FIG. 5, which shows a sealing arrangement for a ball joint otherwise as shown in FIG. 3, the ball stud of the ball joint is again assigned a receiving region 18 which touches the stud-side edge section 7 of the sealing bellows at three circumferential contact surfaces 19, 20, 21, of which an axial contact surface 20 simultaneously adjoins an inner radial contact surface 19 and an outer radial contact surface 21.Again, the contact surfaces of the receiving region 18 are arranged approximately J-shaped to one another in cross section, wherein the inner radial contact surface 19 forms the long leg of the "J", the outer radial contact surface 21 forms the short leg of the "J", and the axial contact surface 20 forms a connecting section of these legs. To absorb both radial and axial sealing forces, the outer radial contact surface 21 encloses an obtuse angle with respect to the axial contact surface 20. In contrast to the first exemplary embodiment of the sealing arrangement, in which the receiving region is formed on a raceway which is designed as a separate component, in the sealing arrangement according to the second exemplary embodiment the receiving region 18 is now formed jointly by contact surfaces 19, 20, 21 which are formed directly on the ball stud 3, in particular stud part 14, and directly on the chassis component 12. A separate raceway is thus not used. At least the contact surfaces 20 and 21 are produced by machining the chassis component 12.Reference numerals denote reference numerals1 Ball joint 2 Joint housing 3 Ball stud 4 Ball part 5 Sealing bellows 6 Housing-side edge section 7 Stud-side edge section 8 Receiving region 9 Inner radial contact surface 10 Axial contact surface 11 Outer radial contact surface 12 Chassis component 13 Raceway 14 Stud part 15 Passage 16 Clamping ring 17 Inner sealing lip 18 Outer sealing lip 19 Inner radial contact surface 20 Axial contact surface 21 Outer radial contact surface 22 Axial sealing lip 23 Inner section 24 Intermediate section 25 Outer section 26 Central axis 27 Center point 30 Stud-side edge section 31 Round wire clamping ring 32 Raceway 33 Chassis component 34 Ball stud 40 Stud-side edge section 41 Clamping ring 43 Chassis component 44 Ball stud

Claims

Sealing arrangement for a ball joint (1) of a chassis, having: a ball stud (3) assigned to the ball joint (1), which stud comprises a ball part (4) and a stud part (14) projecting therefrom and is mounted by means of the ball part (4) in a rotationally and pivotably movable manner with respect to a joint housing (2), and a sealing bellows (5) which, for sealing the ball joint (1) with respect to the environment, is mounted with a housing-side edge section (6) with respect to the joint housing (2) and with a stud-side edge section (7) with respect to the ball stud (3), wherein the ball stud (3) is assigned a receiving region (8; 18) which the stud-side edge section (7) of the sealing bellows (5) touches at three circumferential contact surfaces (9, 10, 11; 19, 20, 21), of which an axial contact surface (10; 20) simultaneously touches an inner radial contact surface (9; 19) and adjoining an outer radial contact surface (11; 21), characterized in that the outer radial contact surface (11; 21) encloses an obtuse angle with respect to the axial contact surface (10; 20) for absorbing both radial and axial sealing forces.Sealing arrangement according to claim 1, characterised in that the pin-side edge section (7) of the sealing bellows (5) directly contacts the three contact surfaces (9, 10, 11; 19, 20, 21) of the receiving region (8; 18).Sealing arrangement according to claim 1 or 2, characterised in that the contact surfaces (9, 10, 11; 19, 20, 21) of the receiving region (8; 18) are arranged approximately J-shaped relative to one another in cross-section, wherein the inner radial contact surface (9; 19) forms the long limb of the "J", the outer radial contact surface (11; 21) forms the short limb of the "J" and the axial contact surface (10; 20) forms a connecting section of these limbs.Sealing arrangement according to one of the preceding claims, characterized in that the outer radial contact surface (11; 21) is designed to absorb both radial and axial sealing forces.Sealing arrangement according to one of the preceding claims, characterized in that the ball stud (3) is connected to a chassis component (12).Sealing arrangement according to one of the preceding claims, characterized in that the pin part (14) for connecting the ball pin (3) to the chassis component (12) projects partially into a recess (15) formed on the latter (12), in order to be received by the latter in a form-fitting manner.Sealing arrangement according to one of the preceding claims, characterized in that a clamping ring (16) is integrated in the material of the pin-side edge section (7) of the sealing bellows (5).Sealing arrangement according to one of the preceding claims, characterized in that the receiving region (8) is formed on a raceway (13) which is mounted with respect to the ball stud (3).Sealing arrangement according to one of Claims 1 to 7, characterized in that the receiving region (18) is formed jointly by contact surfaces (19, 20, 21) which are formed on the ball stud (3) and on the chassis component (12).Sealing arrangement according to Claim 9, characterized in that the contact surfaces (20, 21) formed on the chassis component are produced at least partially by machining.Raceway (13) for use on a sealing arrangement according to one of Claims 1 to 8, characterized byrecirculatory contact surfaces (9, 10, 11), of which an axial contact surface (10) simultaneously adjoins an inner radial contact surface (9) and an outer radial contact surface (11), wherein the outer radial contact surface (11; 21) encloses an obtuse angle with respect to the axial contact surface (10; 20) for absorbing both radial and axial sealing forces.Raceway according to claim 11, characterised in that it is produced as a one-piece shaped sheet metal part, preferably with an approximately J-shaped cross-sectional profile.A raceway according to claim 11 or 12, characterized in that it comprises an inner portion (23) forming the long leg of the "J", an outer portion (25) forming the short leg of the "J", and an intermediate portion (24) connecting the same.Raceway according to one of Claims 11 to 13, characterized in that the inner section (23) is designed to bear against an outer surface of the ball stud (3), in particular its stud part (14), and the intermediate section (24) is designed to bear against the chassis component (12).

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