SE2050489A1 - A seal, a connection assembly comprising a seal, and a vehicle comprising a connection asembly - Google Patents

Abstract

The invention relates to a ring-shaped seal (1) for sealing an end portion of an interface (18) between a shaft (10) and a tube (20). The seal (1) comprises a first, inner widened portion (2) arranged to be in contact with an axial end surface (13) of the shaft (10), a second, outer widened portion (3) arranged to be in contact with an axial end surface (23) of the tube (20), and a waist portion (4) arranged between the first, inner widened portion (2) and the second, outer widened portion (3). The waist portion (4) is arranged to cover the interface (18) without being in direct contact with the surfaces forming the interface. The invention also relates to a connection assembly comprising such a seal and to a vehicle including such a connection assembly.

Description

A SEAL, A CONNECTION ASSEMBLY COMPRISING A SEAL, AND A VEHICLECOMPRISING A CONNECTION ASEMBLY TECHNICAL FIELD The invention relates to a ring-shaped seal and to a connection assembly comprisingsuch a seal. The invention also relates to a vehicle including such a connection assembly.BACKG ROUND ln the automotive industry most products, e.g. vehicles, comprise interconnected partswith interacting surfaces. The interacting surfaces of two such interconnected parts, e.g.a shaft and a tube are often protected from wear by the application of a lubricant between the interacting surfaces.

A lubricant may be grease or it may be a liquid of a viscosity adapted to its application.When lubricants are used in an open or a semi-open interface, i.e. when there is anopening between the interacting surfaces from which the lubricant may escape, it isgenerally desired to seal off the interface in order to keep the lubricant in place and to avoid spillage. ln the event of a connection comprised of a shaft arranged inside a tube, such as splinedshaft and tube, a conventional sealing method is to use a rubber seal which is arranged to seal the open or semi-open interface of the connection bet\Neen the shaft and the tube.

One such arrangement is known from EP 2 787 255 A1, in which an annular seal isprovided to seal the end portion of the connection between a splined shaft and aninteracting tube. The annular seal comprises equidistantly arranged protrusions configured to fit inside the outer gap bet\Neen the splines of the shaft and the tube.

A problem with this arrangement is that the sealing effect have proven to degrade overtime. The invention is based on the notion that the degrading sealing effect is due to thecontinuous interaction bet\Neen the shaft and the tube, and the varying gap width th erebetween. lt would be advantageous to achieve a device overcoming, or at least alleviating, at least one or some of the drawbacks of the prior art.

SUMMARY OF THE INVENTION lt is an object of the invention to provide a solution that provides an efficient sealingbetween a shaft and a tube, which is also efficient over time, or at least has an extended service life with respect to prior art solutions.

This object is achieved by the invention in accordance with a first, second and third aspect thereof.

According to a first aspect the invention relates to a ring-shaped seal configured to sealan end portion of an interface between a shaft and a tube the shaft being arranged insidethe tube, wherein the interface is formed betvveen a radially outermost portion of the shaftand a radially innermost portion of the tube wherein the seal comprises: - a first, inner widened portion arranged to be in contact with an axial end surfaceof the shaft, - a second, outer widened portion arranged to be in contact with an axial endsurface of the tube, and - a waist portion arranged between the first, inner widened portion and thesecond, outer widened portion, wherein the waist portion sealingly connects the first and second widened portions toeach other and is arranged to extend over a full width of the interface between the shaftand the tube.

According to a second aspect the invention relates to a connection assembly comprising:- a shaft and - a tube, wherein the shaft is arranged inside the tube, and wherein an interface is formed between a radially outermost portion of the shaft anda radially innermost portion of the tube, wherein the connection assembly comprises a ring-shaped seal according to the firstaspect, wherein the ring-shaped seal is arranged to seal an end portion of the interface betweenthe radially outermost portion of the shaft and the radially innermost portion of the tube,wherein the first, inner widened portion of the seal is arranged to be in contact with anaxial end surface of the shaft, wherein the second, outer widened portion of the seal is arranged to be in contact with an axial end surface of the tube, and wherein the waist portion of the seal sealingly connects the first and second widened portion to each other and extends over a full width of the interface.

The sealing function o the seal is in accordance with characterising features of the sealachieved by the seal without direct contact of the waist portion of the seal with either the radially outermost portion of the shaft or the radially innermost portion of the tube.

The inventive seal and connection assembly according to the first and second aspects ofthe invention, respectively, provides an efficient tightening of the interface formedbetween the end portions of a shaft and a tube. Further, the fact that the sealing has awaist provided between two widened portions that is arranged to seal the interfacewithout being in direct contact with the end portions of the shaft and the tube, the wear of the seal is substantially reduced so as to drastically increase its service life.

Further, in view of that the seal has few interacting parts with the interface it is arrangedto seal, it is very easy to put in place, and it has a shape that facilitates positioning it in acorrect position. ln embodiments of the first and second aspects of the invention the first, inner widened portion and the second, outer widened portion of the seal have a rounded shape.

The rounded shape provides a better adaptability of the seal to the space in which it is tobe located. Hence, the rounded shape will improve the tolerance of the dimensions of the space to seal off with the seal without endangering the sealing function. ln embodiments of the first and second aspects of the invention the first, inner widenedportion and the second, outer widened portion of the seal have substantially the same thicknesses.

The seal may of course be arranged with a shape to fit its application. A seal with equallythick widened portions is well adapted to an application with equally spaced distancesbetween the end surfaces of the shaft and tube with respect to a retainer or the like arranged to clamp the seal into a sealing position. ln embodiments of the first and second aspects of the invention the waist portion has asubstantially smaller thickness than the thicknesses of the first, inner widened portion andthe second, outer widened portion of the seal. Moreover, the thickness may increasegradually, and/or continuously, from the second thickness towards the first thickness at the two widened portions.

A gradually and/or continuously increasing thickness provides a good force distributionwithin the seal and is beneficial in view of minimising the risk of rupture of the seal as it implies that the seal will have no pointed portions liable to initiation of cracks or crazings. ln embodiments of the first and second aspects of the invention at least one of the firstand the second widened portions of the seal is formed of a twin-ring wherein an annularrecess is formed between individual rings of the tvvin-ring at a radially outermost portion of the ring-shaped seal, or at a radially innermost portion of the seal.

A construction with a recessed twin-ring has the advantage that the radius of the widenedportion will be reduced for a given width, which will imply that the widest part of the sealwill be closer to the periphery or innermost circumferential part of the seal, respectively.ln view of that the widest portion of the seal will be in contact with the axial end surfacesto be sealed off, the effective area to be sealed off may be increased, and the seal maybe more effective in a confined space. ln other words, this embodiment represents anefficient manner of providing a useful contact-free length of the waist portion, as is further described below. ln embodiments of the first and second aspects of the invention the waist portion of theseal has a first length that is defined as the length between a first position where theinner widened portion has a maximal thickness and a second position where the outerwidened portion has a maximal thickness, and wherein the first length represents at least60% of a full length of the seal in the radial direction. ln further specific embodiments thefirst length represents at least 70% or even 75% of the full length of the seal in the radial direction.

The full length of the seal in the radial direction corresponds to the length between the outer radius and the inner radius of the seal. ln an intended use of the seal the waist represents a useful length of the seal in that thewidened portions provides fluid tight sealings in both directions, while the length of thewaist provides a contact-free sealing that is not subject to friction wear. Hence, the longerthe waist the longer the contact-free portion of the seal and the better the margin with respect to the width of the interface between the shaft and the tube. ln embodiments of the first and second aspects of the invention the seal has asymmetrical cross-sectional shape. This is advantageous from both the perspective of producing the seal, and from the perspective of mechanical properties such as elasticity of the seal, Which Will also be symmetrical, thereby providing a symmetrical sealing effect. ln embodiments of the second aspect of the invention the connection assemblycomprises a retainer that is arranged to press the seal into contact with the axial endsurfaces of the shaft and the tube, respectively. The retainer may be fastened to the shaft or to the tube.

An end cap may be secured to the axial end of a connection to axially secure the shaftand the tube to each other. The retainer may be a separate part, or an integrated part of such an end cap. ln specific embodiments of the second aspect of the invention the retainer is fastened tothe shaft and comprises a disc-shaped portion arranged to press the seal into contact with the axial ends of the shaft and the tube, respectively. ln specific embodiments of the second aspect of the invention the retainer comprises anouter rim with a contact surface arranged to extend into contact with a contact surface of the tube radially outside the seal.ln an alternative embodiment, the retainer is attached to the tube instead of the shaft. ln the alternative embodiment, where the retainer is instead attached to tube, the retainercomprises a contact surface arranged to extend into contact with a contact surface of theshaft. ln these embodiments the retainer forms part of an end cap to axially secure the shaft and the tube to each other so as to achieve simultaneous locking and sealing. ln embodiments of the second aspect of the invention the tube comprises acircumferential delimiting surface outside of an interface, and wherein the seal has anouter diameter that corresponds to a diameter of the circumferential delimiting surface,such that the seal is held in position by interaction between its outer widened portion and the delimiting surface of the tube.

This is an efficient manner of correctly positioning the seal, Which also makes it very easy to arrange the seal in a correct position. ln embodiments of the second aspect of the invention the waist portion of the seal has a length that is greater than the full width of the interface, the length of the waist portion being defined as the length between a first position where the inner widened portion hasa maximal thickness and a second position where the outer widened portion has a maximal thickness.

With these embodiments the contact surfaces of the seal will be arranged securelyoutside of the limits of the interface, such that an efficient sealing is achieved with minimised wear of the seal. ln embodiments of the second aspect of the invention the interface is formed of a splined connection between internal splines on the shaft and external splines on the tube. ln this embodiment, details of the external splines of the shaft form the radially innermostpart of the interface and details of the internal splines of the tube form the radiallyoutermost part of the interface. Hence, in this embodiment the full width w of the interfaceis defined as the distance between the details of the external splines of the shaft thatform the radially innermost part of the interface and the details of the internal splines of the tube that form the radially outermost part of the interface.ln embodiments the connection assembly is a power transmission unit. ln specific embodiments of the second aspect of the invention the seal is positioned suchthe first position of the seal is located radially inside the innermost part of the interfaceand the second position of the seal is located radially outside the outermost part of the interface.

According to a third aspect the invention relates to a vehicle comprising a connection assembly as described above.

Other embodiments and advantages will be apparent from the detailed description and the appended drawings.

BRIEF DESCRIPTION OF THE DRAWINGS Below, specific embodiments of the invention will be described with reference to the appended drawings, of which:Fig. 1 shows an exemplary vehicle in accordance with an aspect of the invention, Fig. 2 is an exploded view of a retainer, a seal and a connection assembly in accordance with one embodiment, Fig. 3A is partly cut side view of a ring-shaped seal in accordance with an aspect of the invention,Fig. 3B is a detailed view of part B of the ring-shaped seal in Fig. 3A,Fig. 3C is partly cut side view of a ring-shaped seal of a second embodiment,Fig. 3D is a detailed view of part D of the ring-shaped seal in Fig. 3C, Fig. 4A is an exploded view of a retainer, a seal and a connection assembly in accordance with one embodiment,Fig. 4B is a view of an assembled retainer, seal and connection assembly of Fig. 4A, Fig. 5A is an exploded view of a retainer, a seal and a connection assembly in accordance with a second embodiment,Fig. 5B is a view of an assembled retainer, seal, and connection assembly of Fig. 5A, Fig. 6A is a perspective and partly cut view of a retainer, a seal, and a connection assembly in accordance with one embodiment,Fig. 6B is a detailed view of a portion of Fig. 6A, Fig. 7A is a perspective and partly cut view of a retainer, a seal, and a connection assembly in accordance with a second embodiment, andFig. 7B is a detailed view of a portion of Fig. 7A.

DETAILED DESCRIPTION OF THE SHOWN EMBODIMENTS ln Fig. 1 a vehicle 100 is schematically illustrated, in which a connection assembly 19 in accordance with one aspect of the invention is illustrated in very schematically manner.

The vehicle 100 includes a powertrain with a power source 101, which in the presentexample is exemplified by an internal combustion engine, which, in a conventionalmanner, is connected via an output shaft of the power source 101, via a flywheel 102, toa gearbox 103 via a clutch 106. An output shaft 107 from the gearbox 103 propels drivewheels 113, 114 via a final gear 108, such as a common differential, and half shafts 104,105 connected to said final gear 108. A connection assembly 19 in accordance with one aspect of the invention may be implemented at the output side of the gearbox 103. The connection assembly 19 may also be located at other places in the vehicle 100, and the vehicle 100 may include several connection assemblies 19.

The power source 101 is controlled by a vehicle control system via a control unit 115, andsimilarly the clutch and gearbox may be controlled by a control unit 116, which mayautomatically perform changes of gears. lf the power source is a combustion engine anexhaust pipe 109 is arranged to exhaust combustion gases from said motor via a catalytic converter 110, and preferably a particle filter.

Fig. 2 is an exploded view of a connection assembly 19 in accordance with one aspect ofthe invention. The connection assembly 19 comprises a shaft 10 and a tube 20, the shaft10 being arranged inside the tube 20. An interface 18 is formed between the shaft 10 andthe tube 20. The interface 18 is formed between the interaction between an externalradial surface of the shaft 10 and an inner radial surface of the tube 20. Hence, externalradial surface of the shaft 10 constitutes an innermost and an inner radial surface of thetube 20. ln a specific not shown embodiment where the interface 18 is formed between twosmooth circular surfaces, an annular space or gap is formed between the shaft 10 andthe tube 20, A ring-shaped seal 1 is arranged to seal the interface 18 between the axial end surfaces 13 and 23 of the shaft 10 and the tube 20, respectively. ln the shown embodiment a retainer 30 is arranged to press the seal 1 into contact withthe axial end surfaces 13 and 23 of the shaft 10 and the tube 20, respectively. Theretainer 30 shown in Fig. 2 includes an internal thread 34 arranged to interact with anexternal thread 14 on a protruding part of the shaft 10. Further, the retainer 30 comprisesa grip portion 36 at its periphery for interaction with a tool or a hand of an operator inorder to allow screwing of the retainer 30 onto the tube 10 and to thereby clamp or pressthe seal 1 towards the desired sealing contact with the axial end surfaces 13 and 23 of the shaft 10 and the tube 20, respectively. ln the shown embodiment the tube 20 is connected to a follower 25 for transmitting adriving force from a gear box 103 to the output shaft 107. See Fig. 1. ln fact, in the shownembodiment, the connection assembly 19 is a power transmission unit, and the interface18 is formed of a splined connection between internal splines, forming a radiallyoutermost portion 12 of the shaft 10, and external splines, forming a radially innermostportion 22 of the tube 20. See e.g. Figs 6B and 7B.

As illustrated in Figs. 3A-D, the ring-shaped seal 1 comprises a first, inner widenedportion 2 arranged to be in contact with an axial end surface 13 of the shaft 10, and asecond, outer widened portion 3 arranged to be in contact with an axial end surface 23 ofthe tube 20.

Preferably, the seal 1 is made of an elastic material, such as an elastomer or rubber.

A waist portion 4 is arranged between the first, inner widened portion 2 and the second,outer widened portion 3 of the seal 1. The waist portion 4 is arranged to cover the interface 18 without being in direct contact with the interacting surfaces thereof. ln the shown embodiments, both the first, inner widened portion 2 and the second, outerwidened portion 3 of the seal 1 have a rounded shape and are connected by the waist portion 4. ln this specification the geometry and dimension of the ring-shaped seal 1 is defined as follows: The ring-shaped seal 1 has an inner radius r1 and an outer radius r;, wherein a length Lof the seal is defined as the distance in the radial direction r of the seal, from the inner radius r1 to the outer radius r;.L = f2 - l'1 The thickness t of the ring-shaped seal 1 should be understood as the thickness in anaxial direction along an axial axis A, i.e. orthogonal to the radial direction r, and henceorthogonal to the direction of the length L. The seal 1 has a varying thickness over itslength L, spanning from a maximal, first thickness t1 at the centre of its widened portions to a minimal second thickness t; at a centre of the waist portion 4.

The first, inner widened portion 2 and the second, outer widened portion 3 of the seal 1may have substantially the same thickness, defined as the first thickness t1. Typically, thedifference in thicknesses between first, inner widened portion 2 and the second, outer widened portion 3 of the seal 1 is less than 20%, preferably less than 10% or even 5%.

The waist portion 4 has a substantially smaller, second thickness t; than the firstthickness t1 of the widened portion 2 and 3 of the seal 1. Specifically, the minimal secondthickness t; may be less than 75%, or even less than 60% of the maximal thickness t1.The waist portion 4 may have a gradually and continuously increasing thickness from its position of minimal thickness t; outwards, towards the widened portions 2 and 3.

The total length L of the seal 1 is comprised of a first length |1 of the waist portion 4, asecond length Iz, radially inside of the waist portion 4, and third length lg, radially outside of the waist portion 4.

The first length |1 of the waist portion may be defined as the length bet\Neen a firstposition P1 where the inner widened portion 2 has a maximal thickness t1 and a secondposition P2 where the outer widened portion 3 has a maximal thickness t1. From thisfollows that the second length lg, constitutes the length of the seal radially inside of thefirst position P1, and the third length lg, constitutes the length of the seal radially outside of the second position P2.|1 + lz, + la = L ln the embodiment shown in Figs. 3A and 3B both the first and the second widenedportions 3 and 4, respectively, of the seal 1 are formed of a ring-shaped portion 5 and 6, respectively. ln the embodiment shown in Figs. 3C and 3D both the first and the second widenedportions 3 and 4, respectively, of the seal 1 are formed of a twin-ring 7 and 8,respectively. An annular recess 9 is formed between the individual rings of the twin-rings.An outer annular recess 9 is formed at a periphery or an radially outermost portion of thering-shaped seal 1 between the individual rings of the outer t\Nin-ring 7 and acorresponding inner annular recess 9 is formed at a radially innermost portion of the seal 1 between the individual rings of the inner t\Nin-ring 8. ln the shown embodiments, the seal 1 has a symmetrical cross-sectional shape as seenfrom the waist portion 4, such that the first and second widened portions 3 and 4 arealike. The seal 1 may however very well have an asymmetrical cross-sectional shape.For instance, only the outer second widened portion 3 may be formed by a twin-ring 8, or vice versa. ln both of the shown embodiments the seal 1 has a bone-shaped cross-sectional shape,formed of two lobes, i.e. widened portions 3 and 4, which are connected by a shaft, i.e.the waist portion 4. ln the specific embodiments where at least one of the first and thesecond widened portions 3 and 4 are formed of a twin-ring 7 and 8, respectively, the twin-ring is advantageously formed of two rings, which have a similar cross-sectional diameter, and/or which may be partly merged with each other. 11 Further, with respect to the inner radius and an outer radius ring-shaped seal 1 asdescribed above, the tvvo rings of a twin-ring 7 or 8 are preferably positioned on the sameradial distance from the centre of the axial axis A of the ring-shaped seal 1. Thereby, thetwin-rings 7 and 8 will have their maximal extension along the axial axis A, normal to theradial direction r of the seal 1. ln this way the twin-rings 7 and 8 will contribute effectivelyto the local thickness of the seal 1 at its widened portions 3 and 4, i.e. where it will provide an effective sealing effect. ln Fig. 4A a connection assembly 19 is shown with a seal 1 and a retainer 30 to beattached to the shaft 10. ln Fig. 4B the parts are shown in an assembled state, whereinthe retainer 30 is fastened to the shaft 10 radially inside the seal 1. The retainer 30comprises a disc-shaped portion 31 arranged to press the seal 1 into contact with theaxial ends 11 and 12 of the shaft 10 and the tube 20, respectively. ln this embodiment theretainer 30 includes an internal thread 34 engaged with an external thread 14 on a protruding part of the tube 10.

The retainer 30 comprises an outer rim 32 with a contact surface 34 arranged to extend into contact with a contact surface 24 of the tube 20 radially outside of the seal 1.

A second embodiment is shown in Fig. 5A and 5B, a first difference of this embodimentwith respect to the first embodiment is that the retainer 30 is attached by screws 16 to theshaft 10. lnstead of an internal thread, the retainer 30 includes through holes 35 forallowing passage of the screws 16 into the screw holes 15 arranged in the axial end 11 ofthe shaft 10.

Further, in this embodiment the retainer 30 has a flatter design, such that the contactsurface 33, arranged to be in clamping contact with a contact surface 23 of the tube 20, is formed as a peripheral part of the disc-shaped portion 31. ln Figs. 6A and 7A, the connection assembly is shown in perspective and partly cutviews, wherein Figs. 6B and 7B are detailed views of a part of Figs. 6A and 7A, respectively.

As is apparent from the detailed views, the tube 20 comprises a circumferential delimitingsurface 26 radially outside of the interface 18. The outer diameter of the seal 1 is adaptedto correspond to the diameter of the circumferential delimiting surface 26. Thereby, theseal 1 is held in position by interaction between its outer widened portion 3 and thedelimiting surface 26 of the tube 20. The circumferential delimiting surface 26 is in the shown embodiment formed by a circumferential surface that is orthogonal to the axial end 12 surfaces 13 and 23 of the shaft 10 and the tube 20, respectively. Thereby, thecircumferential delimiting surface 26 and the axial end surface 23 of the tube 20 areinterconnected by a 90 degree angle, wherein the seal 1 is in contact with both thecircumferential delimiting surface 26 and the axial end surface 23 of the tube 20, and in sealing contact with at least the axial end surface 23 of the tube 20.

As is i||ustrated in Fig. 7B, the waist portion of the seal 1 has a length |1 that is greaterthan the full width w of the interface 18. As explained above the length |1 of the waistportion, is defined as the length between a first position P1 where the inner widenedportion 2 has a maximal thickness t1 and a second position P2 where the outer widenedportion 3 has a maximal thickness t1. See Fig. 2. lt may of course be advantageous tohave a safety margin, such that the length |1 of the waist portion 4, is clearly greater thanthe full width w of the interface 18, such as for example at least 5%, or at least 10% or20%, greater than the full width w of the interface 18.

The interface 18 is formed between a radially outermost portion 12 of the shaft 10 and a radially innermost portion 22 of the tube 20. ln the shown embodiment, the interface 18 is formed of a splined connection betweeninternal splines, forming the radially outermost portion 12 of the shaft 10, and externalsplines, forming the radially innermost portion 22 of the tube 20. The full width w of theinterface 18 is hence comprised of the distance between the radially innermost part of theinternal splines of the shaft 10 and the radially outermost part of the external splines ofthe tube 20. The first position P1 should accordingly be located radially inside aninnermost part of the interface 18 formed by the internal splines and the second positionP2 should be located radially outside an outermost part of the interface 18 formed by the external splines.

Above, the invention has been described with reference to specific embodiments. Theinvention is however not limited to these embodiments. lt is obvious to a person skilled in the art that other embodiments are possible within the scope of the following claims.

Claims (5)

1. _ A ring-shaped seal (1) configured to seal an end portion of an interface (18) between a shaft (10) and a tube (20) the shaft (10) being arranged inside the tube (20),wherein the interface (18) is formed between a radially outermost portion (12) of theshaft (10) and a radially innermost portion (22) of the tube (20), wherein the seal (1) comprises: - a first, inner widened portion (2) arranged to be in contact with an axial endsurface (13) of the shaft (10), - a second, outer widened portion (3) arranged to be in contact with an axial endsurface (23) of the tube (20), and - a waist portion (4) arranged between the first, inner widened portion (2) and thesecond, outer widened portion (3), wherein the waist portion (4) sealingly connects the first and second widened portions(2,3) to each other and is arranged to extend over a full width (w) of the interface (18)between the shaft (10) and the tube (20)_ The ring-shaped seal (1) according to claim 1, wherein the first, inner widened portion (2) and the second, outer widened portion (3) of the seal (1) have a rounded shape_ The ring-shaped seal (1) according to claim 1 or 2, wherein the first, inner widened portion (2) and the second, outer widened portion (3) of the seal (1) have substantially the same thicknesses (t1)_ _ The ring-shaped seal (1) according to claim 3, wherein the waist portion (4) has a substantially smaller second thickness (t2) than the first thickness (t1) of the first, innerwidened portion (2) and the second, outer widened portion (3) of the seal (1), andwherein the thickness increases gradually from the second thickness (t2) towards the first thickness (t1)_ _ The ring-shaped seal (1) according to anyone of the preceding claims, wherein at least one of the first and the second widened portions (3,4) of the seal (1) is formed ofa twin-ring (7,8), wherein an annular recess (9) is formed between individual rings ofthe tvvin-ring (7,8), at a radially outermost portion of the ring-shaped seal (1), and/or at a radially innermost portion of the seal (1)_ The ring-shaped seal (1) according to anyone of the preceding claims, wherein the waist portion (4) of the seal (1) has a first length (l1) that is defined as the lengthbetween a first position (P1) where the inner widened portion (2) has a maximal thickness (t1) and a second position (P2) where the outer widened portion (3) has a 10 11. 1

2. 14 maximal thickness (t1), and wherein the first length (l1) represents at least 60% of a full length (L) of the seal (1) in the radial direction. A connection assembly (19) comprising: - a shaft (10) and - a tube (20), wherein the shaft (10) is arranged inside the tube (20), and wherein an interface (18) is formed between a radially outermost portion (12) ofthe shaft (10) and a radially innermost portion (22) of the tube (20), wherein the connection assembly (19) comprises a ring-shaped seal (1) according to anyone of the preceding claims. The connection assembly (19) according to claim 7, wherein the connection assembly(19) comprises a retainer (30) arranged to press the seal (1) into contact with theaxial end surfaces (13,23) of the shaft (10) and the tube (20), respectively. The connection assembly (19) according to claim 8, wherein the retainer (30) isfastened to the shaft (10) and comprises a disc-shaped portion (31) arranged to pressthe seal (1) into contact with the axial end surfaces (13,23) of the shaft (10) and thetube (20), respectively. The connection assembly (19) according to claim 9, wherein the retainer (30)comprises an outer rim (32) with a contact surface (33) arranged to extend into contact with a contact surface (24) of the tube (20). The connection assembly (19) according to anyone of the claims 7-10, wherein thetube (20) comprises a circumferential delimiting surface (26) outside of the interface(18), and wherein the seal (1) has an outer diameter that corresponds to a diameterof the circumferential delimiting surface (26), such that the seal (1) is held in positionby interaction between its outer widened portion (3) and the delimiting surface (26) ofthe tube (20). The connection assembly (19) according to anyone of the claims 7-11, wherein thewaist portion (4) of the seal (1) has a length (l1) that is greater than the full width (w)of the interface (18), the length (l1) of the waist portion (4) being defined as the length(l1) between a first position (P1) of the seal (1)where the inner widened portion (2)has a maximal thickness (t1) and a second position (P2) of the seal (1) where the outer widened portion (3) has a maximal thickness (t1). 1

3. The connection assembly (19) according to anyone of the claims 7-12, wherein theinterface (18) is formed of a splined connection bet\Neen internal splines on the shaft (10) and external splines on the tube (20). 1

4. The connection assembly (19) according to claim 12, or claim 13 in dependence ofclaim 12, wherein the seal (1) is positioned such the first position (P1) of the seal (1)is located radially inside the radially outermost portion (12) of the shaft (10) and thesecond position (P2) of the seal (1) is located radially outside the radially innermostportion (22) of the tube (20). 1

5. A vehicle (100) comprising a connection assembly (5) according to anyone of the claims 7-14.