WO2015180764A1

WO2015180764A1 - Sealing assembly with anti-rotation structure

Info

Publication number: WO2015180764A1
Application number: PCT/EP2014/061008
Authority: WO
Inventors: Sylvain Chaussat; Franck Landrieve
Original assignee: SKF AB
Current assignee: SKF AB
Priority date: 2014-05-28
Filing date: 2014-05-28
Publication date: 2015-12-03
Anticipated expiration: 2016-11-28

Abstract

Sealing assembly with anti-rotation structure The invention relates to a sealing assembly including a first part(11) including a first sealing component (36) and a second part (21) including a second sealing component (22, 40) in sliding contact with the first sealing component (36), wherein the first part (11) is configured to be connected to a first ring of a bearingand the second part (21) is configured to be connected to a second ring of the bearing so as to be rotatable relative to one another. It is proposed that that a radial surface of one or the parts (11, 21) of the sealing configured to befitted onto-or into a supporting part (10, 12) is provided with an anti-rotation structure (52) of elastomeric material for avoiding a creeping rotation of the part (11, 21) in relation to the supporting part (10, 12).

Description

Sealing assembly with anti-rotation structure Technical field The invention relates to a sealing assembly to be mounted on/or in a ring of a rolling bearing .

Background of the invention It is known to use labyrinth seals and/or sealing lips interposed between two rings of a rolling bearing, wherein the sealing lip fixed on one of the rings may be in sliding contact with the other ring or with a pertinent sealing member fixed thereto. Further, the document WO2011/121383 Al teaches to provide a rolling bearing with a sensor unit in order to determine a rotation parameter of an outer ring with respect to an inner ring . A Hall-effect cell is attached to the first part of the sensor unit which is fixed to a shaft and thereby fast in rotation with the inner ring. An encoder washer is fixed to the outer ring of the bearing and the space between the Hall-effect cell and the encoder washer is protected by a sealing gasket.

It is further known to use sensor arrangements in a cartridge design, which can be mounted as one piece. However, a general problem if sensor arrangements is that creeping phenomena may lead to wear and to insufficient sealing performance.

It is therefore an object of the invention to provide a sealing arrangement with reduced creeping.

Summary of the Invention

The invention relates to a sealing assembly including a first part including a first sealing component and a second part including a second sealing component in sliding contact with the first sealing component, so as to be rotatable relative to one another. It is proposed that that a radial surface of one or the parts of the sealing configured to be fitted onto- or into a supporting part is provided with an anti-rotation structure of elastomeric material for avoiding a creeping rotation of the part in relation to the supporting part.

Preferably, the part provided with the anti-rotation structure is a radially outer part of the sealing assembly, where the displacements due to unintended rotations are larger. Preferably, the first part is configured to be connected to a first ring of a bearing and the second part is configured to be connected to a second ring of the bearing .

Unintended rotation due to creeping are particularly detrimental in sealing assemblies including a sensor arrangement because the transmission of the sensor signals to the outside may be impaired in this case. Accordingly, the advantages of the invention are particularly important in the case where the part provided with the anti-rotation structure is a part comprising electronic components of the sensor assembly.

In a preferred embodiment of the invention, the sensor arrangement further includes at least one circuit board equipped with at least one electronic component arranged in an interior space of the sealing assembly and at least one wire connected to said circuit board, wherein at least one of said sealing components is provided with a channel for guiding the wire from the interior space to an outside of the interior space. The anti-rotation structure may avoid tensions or damages of the wire as they may result from unintended rotations or its supporting parts. According to a further aspect of the invention, the assembly includes a supporting ring holding a wire serving as antenna for transmitting signals generated by the sensor arrangement, wherein the anti-rotation structure is provided on a radially outer surface of the supporting ring . In a preferred embodiment of the invention, the assembly comprises a flange with a sealing lip consisting of a rubber material, wherein anti-rotation structure consists of the rubber material of the sealing lip. Using the same material for the two different structures and different functions may lead to a reduction of manufacturing costs. Preferably, the flange comprises a cylindrical portion provided with the anti-rotation structure and a portion protruding radially inward provided with the sealing lip. The manufacturing costs may be reduced even further when the anti-rotation structure and the sealing lip are formed in the same manufacturing step, in particular when the anti-rotation structure and the sealing lip are formed by overmoulding combined with vulcanization. The sealing performance can be further improved when anti-rotation structure is formed as a closed ring and configured to seal a gap between the sealing assembly and the supporting part.

In cases where the sensor comprising a sensor arrangement including electronic components, it is possible to avoid short-cuts while saving on manufacturing costs by coating at least one surface of said flange facing said electronic components with the electrically insulating material of the sealing lip and/or of the anti-rotation structure. This holds in particular where the sensor arrangement comprises a sensor and electronic devices for reading out the sensor signals and/or for pre-processing the sensor signals of the sensor. Damages of these fragile components may be avoided or reduced by a damping effect of the coating.

In a preferred embodiment, the assembly includes generator means or harvester means for generating energy for self-powering electronic devices of the sensor assembly.

Damages of the seal or of other components during transport or handling may be avoided, when the assembly comprises a magnetic encoder ring attached to one of the first part and the second part, wherein the magnetic encoder ring exerts the magnetic attraction to at least one component of the other part out of the first part and the second part such that a gap between the encoder ring and the pertinent sensor means or generator means is closed in the absence of external forces and upon transporting and handling the sensor assembly. The following non-limiting description of embodiments of the invention as well as the appended claims and figures show multiple characterizing features of the invention in specific combinations. The skilled person will easily be able to consider further combinations or sub-combinations of these features in order to adapt the invention as defined in the claims to his specific needs.

Brief description of the drawings Fig. 1 is a sectional view of a hub including a sealing assembly according to a first embodiment of the invention;

Fig. 2 is an enlarged view of the sealing assembly in Fig. 1;

Fig. 3 is a sectional view of the sealing assembly according to Figs.

1 - 3; Fig. 4 is a perspective view of a cartridge constituting the sealing assembly according to the first embodiment of the invention;

Fig. 5 is a further perspective view of the cartridge constituting the sealing assembly according to the first embodiment of the invention; Fig. 6 is an exploded view of the sealing assembly according to the first embodiment of the invention;

Fig. 7a is a sectional view of the sealing assembly according to Figs.

1 - 6 in transport configuration;

Fig. 7b is a sectional view of the sealing assembly according to Figs.

1 - 6 in an intermediate state;

Fig. 7b is a sectional view of the sealing assembly according to Figs.

1 - 6 in its operating configuration;

Fig. 8 is a perspective view of an antenna and of an antenna carrier ring of the sealing assembly according to Figs. 1 - 7; Fig. 9 is a perspective view of the antenna carrier ring holding the antenna according to Fig. 8;

Fig. 10 is a perspective view of a hub unit including a sealing assembly according to a second embodiment of the invention;

Fig. 11 is a sectional view of the hub unit sealing assembly according to the second embodiment of the invention;

Fig. 12 is a partial view of the sealing assembly according to Fig. 11;

Fig. 13 is a sectional view of the sealing assembly according to the second embodiment of the invention;

Fig. 14 is a perspective view of a sleeve carrying an antenna in a sealing assembly according to the second embodiment of the invention;

Fig. 15 is an exploded view of the sealing assembly according to the second embodiment of the invention;

Fig. 16 is a perspective view of a cartridge constituting a sealing assembly according to the second embodiment of the invention;

Fig. 17 is a further perspective view of the cartridge according to the second embodiment of the invention;

Detailed description of the embodiments

Fig . 1 is a sectional view of a hub 10 of a light motorcycle. A body of the hub 10 is mounted on a shaft 12 via two single-row ball bearings 14a, 14b, wherein the outer rings of the bearings 14a, 14b are fitted into the hub 10 and the inner rings are fitted over the shaft 12 and are held in place by a spacer ring 16 and a bushing 18. The bearing 14b on the right hand side is sealed by a sealing assembly 20 according to the invention, which is fitted into a pertinent recess of the hub 10 such that the hub 10 serves as a first supporting part of the sealing assembly.

The sealing assembly 20 is fitted over the shaft 12 being a second supporting part for the sealing assembly, wherein a sleeve 22 may be provided between a metallic flange 24 of the sealing assembly and the shaft 12 if the inner diameter of the flange 24 does not match the outer diameter of the shaft 12. The radial thickness of the sleeve 22 can be adapted to the outer diameter of the shaft 12 such that the rest of the assembly may be used for multiple different shaft diameters. Further, it is possible to use a similar sleeve between the outer diameter of the sealing assembly 20 and the inner diameter of a bore in the body of the hub 10 if these do not match.

Figs. 2 and 3 are enlarged views of the sealing assembly 20 according to the first embodiment of the invention. The sealing assembly 20 has two parts which are rotatable relative to one another, wherein the first, inner part is fastened to the shaft 12 so as to rotate with the shaft 12 and the second, outer part is fastened to the body of the hub 10 via an outer flange 34 and rotates together with the latter. Sensor means are arranged within the sealing assembly and are suitable for measuring the rotational speed of the hub 10.

As described in further detail below, the measurement values of the sensor mans or speed data depending thereon are transmitted to a control unit (not illustrated) outside of the hub 10 e.g . to a tachometer of a motorcycle being equipped with the hub 10. Besides of measuring the rotational speed, the sealing assembly 20 seals the sensor means received therein as well as the bearing 14b such that the intrusion of dust or the like is avoided. The sensor means in the embodiment of Fig. 2 comprises a Hall sensor 28 and a magnetic encoder ring 26 fixed on the flange 24 connected to the shaft 12 arranged opposite to the Hall sensor 28 mounted on a printed circuit board 30 arranged in an interior space of the sealing assembly. The interior space is the space axially limited by the flange 34 and the sealing lip on the one hand and the encoder ring 26 on the other hand . The printed circuit board 30 is mounted on a plastic support ring 32 (Fig. 1, Fig. 6) fitted into the outer flange 34. The outer flange 34 has a cylindrical portion and a portion protruding radially inward, wherein the radially inner part of the flange 34 is provided with a sealing lip 36. The lip 36 is overmoulded or vulcanized onto the flange 34 and the rubber or sealing material covers a side of the flange facing the electronic components of the sensor assembly mounted on the printed circuit board 30. The sealing lip 36 is preloaded with a circular spring 37 and is in sliding contact with the corresponding sealing bushing 40 provided with a radial deflection part and an axial portion which is fitted over the sleeve 22 and rotates with the first part of the sealing assembly.

The last-mentioned bushing 40 and the flange 24 are portions which protrude radially outward from the sleeve 22 up to a radius exceeding the inner radius of the flange 34 such that the assembly cannot be detached in an non-destructive way by axially moving the first part of the sealing arrangement relative to the second part of the sealing arrangement.

The first part of the sealing arrangement comprises the sleeve 22, the flange 24, the bushing 40 and the encoder ring 26 and the second part fixed to the hub body comprises the flange 25, the sealing lip 36, the support ring 32, the printed circle port 30, the Hall sensor 28 and further electronic components for the sensor assembly mounted on the printed circle port 30. The two parts of the sealing assembly can be more clearly distinguished in the simplified Figs. 7a - 7c below, where the components belonging to the first part are illustrated with a simple hatching and the components belonging to the second part are illustrated with a cross-hatching.

Attached to an axially outer side of the flange 24 facing away from the circuit board 30 arranged in a sealed inner space of the sealing assembly is a supporting ring 44 supporting a wire formed as an antenna 46 (Fig. 6). The supporting ring 44 is a plastic part fixed to the flange 24 by means of pins 48 which extend through associated holes on the radial portion of the flange 24. The pins 48 may further serve to fix the printed circuit board 30 to the flange 24. Other fixing means are possible such as glue, vulcanization, screws, overmoulding etc. Preferably, the pins 48 are heated in order to ensure a secure material bonded connection. Besides of the holes for the pins 48, the flange 24 comprises holes for guiding the antenna 46 outside the interior space of the sensor arrangement which is electromagnetically screened by the metallic flange 24. The antenna 46 is connected to the printed circuit board by welding or via a coaxial switch.

Due to the meshing radial portions of the first part and of the second part of the sealing assembly, the parts cannot be detached and are combined to form a stable cartridge which can be handled as one piece when being mounted in the hub 10 by fitting the cartridge over the shaft 12 and pushing it into the recess. The meshing radial protrusions are, however, designed in such a way that an axial play essentially equal to the width of an air gap 49 between the encoder ring 26 and the Hall sensor 28 is possible. The magnetic encoder ring 26 exerts a magnetic attraction force to the Hall sensor 28 and to other metallic parts on the printed circuit board 30 and/or to the flange 34. In the transport configuration illustrated in Fig . 7a and Fig . 7b, the magnetic attraction force closes the gap 49 between the encoder ring 26 and the Hall sensor 28 and makes the Hall sensor 28 stick to the encoder ring 26 unless these are separated by an external force. As a consequence, the two parts of the sealing assembly 20 stick together and are not loose when handling or transporting the cartridge.

Figs. 4 and 5 illustrate the cartridge in an unmounted configuration and in different perspective views. The antenna 46 is embedded into the plastic support ring 44 by overmoulding or otherwise. Opposite thereto, protruding legs 50 of the support ring 32 protrude axially over the radially outermost surface of the flange 34.

The outer flange 34 may optionally be provided with an overmoulded anti- rotation structure formed as a rubber ring 52 for sealing and anti-rotation purposes.

Fig. 6 is an exploded view of the sealing assembly 20 according to the first embodiment of the invention. For mounting the assembly, the bushing 40 with the regularly protruding deflector is press-fitted over the sleeve 22. In alternative embodiments, the connection between the sleeve 22 and finally the flange 24 may be achieved otherwise, e.g . by bonding, gluing, snap- fitting or screwing . The printed circuit board 30 is essentially ring-shaped with cut-outs on its outer circumference and can be fitted into the supporting ring 32 from below. The supporting ring 32 is provided with protrusions 54 at the radially inner side of its legs 50 and the cut-outs of the printed circuit board 30 are such that the printed circuit board 30 can be axially pushed over the protrusions 54 in a suitable orientation. The printed circuit board 30 is then rotated and axially supported by the protrusions 54.

The supporting ring 32 (without the pins 48) provided with a printed circuit board 30 is then fitted into the outer flange 34 and the supporting ring 44 with the antenna 46 on the axially outer side of the outer flange 34 such that the latter is sandwiched between a supporting ring 32 and the supporting ring 34. The assembly is fixed by means of the pins 48 connecting the supporting ring 44, the flange 34 and the supporting ring 32. This assembly is then fitted over the sleeve 22 and finally the flange 24 with the encoder ring 26 is press-fitted over the axial end of the sleeve 22 so as to form a stable cartridge. In alternative embodiments, the connection between the sleeve 22 and finally the flange 24 may be achieved otherwise, e.g . by bonding, gluing, snap-fitting or screwing. It is worthwhile to note that the end face of the supporting ring 34 is provided with holes 34a for the pins and with holes 34b for the antenna 46 having the function of a channel 58 for guiding the wire formed as the antenna 46 from the interior space to an outside of the interior space. The holes 34b for the antenna are at least partially filled with the rubber material of the sealing lip 36 with which the inside of the supporting ring 34 facing the electronic components of the sensor assembly is coated in such a way that the channel is configured such that the rubber material encompasses the wire and that the rubber material is stretched by the antenna wire 46 so as to bear with an elastic force on a radially outer surface of the antenna wire 46. This achieved by the diameter of the hole forming the channel 58 in the unstretched configuration illustrated in Fig. 6 being smaller than an outer diameter of the antenna wire 46.

Fig . 7a illustrates the cartridge in a transport configuration where no gap 49 between the encoder ring 26 and the hall sensor 28 is magnetically attracted by the encoder ring 26. When the cartridge forming the sealing assembly 20 is pushed into the recess of the hub 10, the axial ends of the legs 50 will come in contact with the bottom face of the recess or bore in the hub 10 as illustrated in Fig. 7b and will define the axial position of the second, outer part 21 of the sealing assembly. The sleeve 22 of the first part 11 can then be pushed further axially inward until it comes to abutment with the inner ring of the bearing 14b while the second part 21 is stopped at the position defined by the legs 50. As a consequence, the gap 49 between the Hall sensor 28 and the encoder ring 26 will be opened as illustrated in Fig . 7c.

Fig . 8 shows the antenna 46 and the supporting ring 44 separated from each other and Fig. 9 shows the supporting ring 44 with the antenna 46. The antenna may be received in a suitably interior space of the supporting ring 44 or may be integrally moulded with the supporting ring 44. The dotted line in Fig . 8 illustrates a further embodiment of the invention where the ring- shaped sealing- and anti-rotation structure 52 is moulded onto the supporting ring .

Figs. 10 - 17 show a second embodiment of the invention. The following description of the second embodiment of the invention will be generally limited to the differences to the first embodiment of the invention as described above. The reader is referred to the above description of the first embodiment with regard to features which are unchanged . In order to simplify the understanding, features with identical or similar functions are labeled with the same reference numbers. In the embodiment of Figs. 10 - 17, the printed circuit board 30 is fixed to a sleeve 22 attached to the shaft 12 and the magnetic encoder ring 26 is attached to a flange 34 which rotates together with the body of the hub 10. The encoder ring 26 includes magnets or magnetic particles embedded in a plastics material or overmoulded which is fixed in holes in the axial end face of the outer flange 34. The outer flange 34 is provided with an overmoulded rubber ring 52 for sealing and anti-rotation. This anti-rotation feature is preferably provided in the part of the sealing assembly which guides the antenna 46 or another wire to the outside, in particular in case where that wire is - unlike the antenna - connected to other components. The anti- rotation means could be formed otherwise than by a rubber ring 52 or rubber lip and avoids that a creeping rotation of the pertinent part or the sealing assembly leads to damages of the wire or of the sealing function. As illustrated in Figs. 10 - 13, the antenna 46 is guided from the printed circuit board 30 along the shaft 50 to the outside of the space screened by the flange 24 and is fitted into a circumferential groove 56 on the axial end face of the radial portion of the sleeve 22 as illustrated in Figs. 14 and 17. The sleeve 22 may be made of different plastic materials or different parts fitted together including the first radial portion holding the antenna 46 as illustrated in Fig. 6 and the second radial portion holding the printed circuit board 30 as illustrated in Fig . 7. A cylindrical core part of the flange 24 may be formed of a material with higher rigidity or of metal sufficiently hard to support the forces acting on the wheel, in particular of metal .

Fig. 15 is an exploded view of the sealing assembly 20 according to the second embodiment of the invention. As for the mounting procedure, the antenna 46 is mounted in the groove 56 on the flange 24 and its end part is guided through an axial groove 58 on the radially inner side of the sleeve 22. In the embodiment illustrated in Fig. 15, the sleeve 22 is composed of a metallic core part 22a and a plastic part 22b protruding radially outward and receiving the antenna 46 in its groove 56. The plastic part 22b forms a labyrinth with the flange 34 protruding radially inward and deflects liquids or particles toward an axial end face of the flange 34.

The encoder ring 26 is fitted into the outer flange 34 and fixed thereto with pins 48. Alternatively, the encoder ring 26 may be formed by overmoulding, fixed to the flange 34 by bonding or curing or simply be held in place by the magnetic attraction force. In the second embodiment of the invention, the sealing lip 36 moulded on the flange 34 is in direct sliding contact with the sleeve 22. The printed circuit board 30 with the hall sensor 28 or coil arrangement is mounted in a supporting ring 32 having protrusions 54 for a snap-fitting connection. The flange 34 with the encoder ring 26 is then fitted over the sleeve 22 and then the supporting ring 32 is fixed to the sleeve 22 by positive engagement of protrusions 60 with pertinent recesses 62 in the sleeve. Metal strips 64 on the axial end of the outer flange 34 can be folded radially inward so as to encompass the supporting ring 32 and to prevent an unintended dismantling of the partridge due to excessive axial play. The final configuration of the cartridge is different views in Figs. 16 and 17. The axial play limited by the metal strips 64 on the one hand and by the contact between the plastic part 22b of the sleeve and the flange 34 is set in such a way that damages of the sealing lip are safely avoided . In all the embodiments of above, the Hall sensor may be used as or replaced by an energy harvester as generator means for generating energy for self- powering electronic devices of the sensor assembly with a capacity sufficient to drive the electronic components mounted on the printed circuit board 30. The harvester may include one or more piezo crystals or coils configured to extract field energy from the oscillating magnetic field generated by the encoder ring . The piezo-elements may be connected to the printed circuit board via elastomeric connectors as elastomeric connector pads on the market allowing for a sufficient amount of deformation. A thickness of the elastomeric connector layer available may be in the range between 0,5 and 1,5 mm. The piezo-elements may be placed on a side of the printed circuit board 30 facing the encoder ring whereas the other electronic components may be placed on the other side of the printed circuit board 30. In this case, the elastomeric connector may be formed as an elastomeric seal having an additional sealing function.

Further the antenna 46 may be replaced by a cable for transmitting or transporting energy or sensor data from and to the sensor assembly and the printed circuit board . A connector may be provided on an outer surface of the cartridge for connecting the sensor arrangement to a data processing unit for processing the sensor data and/or for supplying energy to the sensor arrangement. Besides of or instead of a sensor for measuring the rotational speed, it is possible to provide temperature sensors, vibration sensors, pressure sensors or other kinds of sensors on the printed circuit board 30 or in other places inside the cartridge.

Claims

Sealing assembly including a first part (11) including a first sealing component (36) and a second part (21) including a second sealing component (22, 40) in sliding contact with the first sealing component (36), so as to be rotatable relative to one another, characterized in that a radial surface of one or the parts (11, 21) of the sealing configured to be fitted onto- or into a supporting part (10, 12) is provided with an anti-rotation structure (52) of elastomeric material for avoiding a creeping rotation of the part (11, 21) in relation to the supporting part (10, 12).

Sealing assembly according to claim 1,

wherein the first part (11) is configured to be connected to a first ring of a bearing and the second part (21) is configured to be connected to a second ring of the bearing, the first and second rings being rotatable relative to one another.

Sealing assembly according to claim 1 or 2,

characterized in that the part (21) provided with the anti-rotation structure is a radially outer part of the sealing assembly.

Sealing assembly according to one of the preceding claims,

characterized by further including a sensor arrangement, wherein the part (21) provided with the anti-rotation structure (52) is a part comprising electronic components of the sensor assembly.

Sealing assembly according to one of the preceding claims,

characterized in that the sensor arrangement further includes at least one circuit board (30) equipped with at least one electronic component (26) arranged in an interior space of the sealing assembly and at least one wire (46) connected to said circuit board (30), wherein at least one of said sealing components (36, 22, 40) is provided with a channel (58) for guiding the wire (46) from the interior space to an outside of the interior space.

6. Sealing assembly according one of claims 4 and 5, characterized by comprising a supporting ring (44) holding a wire serving as antenna (46) for transmitting signals generated by the sensor arrangement, wherein the anti-rotation structure (52) is provided on a radially outer surface of the supporting ring (44).

7. Sealing assembly according one of the preceding claims,

characterized by comprising a flange (34) with a sealing lip (36) consisting of a rubber material, wherein anti-rotation structure (52) consists of the rubber material of the sealing lip (38).

8. Sealing assembly according claim 6,

characterized in that the flange (34) comprises a cylindrical portion provided with the anti-rotation structure (52) and a portion protruding radially inward provided with the sealing lip (36).

9. Sealing assembly according claim 6 or 7,

characterized in that the anti-rotation structure (52) and the sealing lip (38) are formed in the same manufacturing step.

10. Sealing assembly according claim 6, 7 or 8,

characterized in that the anti-rotation structure (52) and the sealing lip (38) are formed by overmoulding.

11. Sealing assembly according to one of the preceding claims,

characterized in that the anti-rotation structure (52) is formed as a closed ring and configured to seal a gap between the sealing assembly and the supporting part (10, 12).

12. Sealing assembly according to one of claims 7 - 10,

characterized by comprising a sensor arrangement including electronic components, wherein at least one surface of said flange (34) facing said electronic components (26, 30) is coated with the electrically insulating material of the sealing lip (36) and/or of the anti-rotation structure.

13. Sealing assembly according to one of the preceding claims, characterized in that the sensor arrangement comprises a sensor (28) and electronic devices for reading out the sensor signals and/or for pre-processing the sensor signals of the sensor (28).

14. Sealing assembly according to one of the preceding claims, characterized by comprising generator means (28, 26) for generating energy for self-powering electronic devices of the sensor assembly.

15. Sealing assembly according to one of claims 12 - 14, characterized by including a magnetic encoder ring (26) attached to one of the first part (11) and the second part (21), wherein the magnetic encoder ring (26) exerts the magnetic attraction to at least one component of the other part out of the first part (11) and the second part (21) such that a gap (49) between the encoder ring (26) and the pertinent sensor means (28) or generator means is closed in the absence of external forces and upon transporting and handling the sensor assembly.