WO2015180763A1

WO2015180763A1 - Sealing assembly, notably for rolling bearings

Info

Publication number: WO2015180763A1
Application number: PCT/EP2014/061007
Authority: WO
Inventors: Sylvain Chaussat; Franck Landriève
Original assignee: Aktiebolaget Skf
Priority date: 2014-05-28
Filing date: 2014-05-28
Publication date: 2015-12-03

Abstract

The invention relates to a sealing assembly comprising a sensor arrangement and including a first part (11) and a second part (21), wherein the first part (11) is configured to be connected to a first ring of a bearing (14b) and the second part (21) is configured to be connected to a second ring of the bearing (14b) so as to be rotatable relative to one another. It is proposed that the first part (11) and the second part (21) of the assembly are pre-assembled in an undetachable way so as to form a compact cartridge which can be mounted as one single component.

Description

Sealing assembly, notably for rolling bearings 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.

However, the sealing assembly can be easily disassembled and is formed by two separate parts of the unit. As a consequence, they cannot be pre- assembled and maintained together during the transport. A further example of such a combined sealing and sensor arrangement is disclosed in WO 2011/045637.

It is therefore an object of the invention to provide a combined sealing and sensor arrangement which can be pre-assembled and easily mounted as a compact assembly in the device where it is finally used .

Summary of the Invention The invention concerns a sealing assembly comprising a sensor arrangement including a first part and a second part, wherein 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 so as to be rotatable relative to one another. In this context, the expression "connected to" means that the parts rotate with each other when the bearing is operating. It is proposed that the first part and the second part of the assembly are pre-assembled in an undetachable way so as to form a compact cartridge which can be mounted as one single component.

The pre-assembly facilitates the mounting procedure, i.e. the procedure of mounting the sealing assembly in the rolling bearing or in the device where it is intended to be used avoids assembly errors and helps to guarantee tolerances. The fragile and sensitive components of the sensor assembly can be effectively protected inside the cartridge when the cartridge is mounted, transported or handled.

In a preferred embodiment of the invention, an encompassing part out of said first part and said second part comprises a cylindrical portion and at least two radial portions radially protruding from the cylindrical portion respectively, wherein the other one of said first part and said second part is an engaging part and comprises at least one portion protruding radially in a direction opposite to the two radially protruding portions of the encompassing part up to a diameter exceeding the end diameter of the two radial portions in their protruding direction such that the one radial portion meshes with the at least two radial portions. If the encompassing part is the inner part and has protrusions protruding radially outward the at least one protrusion of the engaging part should have an inner diameter smaller than the outer diameter of the protrusions of the encompassing part. If the encompassing part is the inner part and has protrusions protruding radially inward the at least one outward protrusion of the engaging part should have an outer diameter smaller than the inner diameter of the protrusions of the encompassing part.

It is to be noted that the expression "undetachable" in this context means that the two parts are unlikely to disassemble in the course of regular handling operations or during transport. The force needed to disassemble the two parts should be at least 10 N, preferably 100 N or more. Further, it is proposed that the cartridge comprises a sensor and electronic devices for reading out the sensor signals and eventually pre-processing the sensor signals. Preferably, the printed circuit board is integrated in the assembly in a sealed space.

Further, it is proposed that the sealing assembly comprises generator means for generating energy for self-powering the electronic devices in the cartridge. The generator means may include piezo-elements or cells interacting with magnetic devices fixed to the part of the assembly which rotates relative to the magnetic sensor or coil device. The self-powering function is particularly advantageous in cases where the assembly includes a wireless communication interface such as an antenna for transmitting signals generated based on the sensor to the outside. In a preferred embodiment of the invention, the magnetic encoder ring is magnetically attracted to a coil or a ring attached to the part configured to rotate relative to the encoder ring in the pre-assembled state for save handling. A gap between the magnetic parts of the encoder ring and the pertinent magnetic sensors opposing these parts may be opened and fixed in its width only in the course of mounting the cartridge in its final destination, wherein the mounting procedure may include exerting axial forces sufficient to overcome the magnetic force and to separate the encoder ring from an opposing ferromagnetic ring or harvester. Magnetic attraction may avoid a dangling of the parts in the course of transport which could impair the sealing quality of the sealing lips.

Further, it is proposed that one of the parts of the sealing assembly includes a ring having a channel or groove suitable for receiving an antenna and/or electric cable for powering and/or reading out the sensor which is suitable for leading the antenna and/or cable from a sealed inside space of the cartridge to the outside thereof. If the ring provided with the channel or groove is designed to be the rotating ring, it can be used for receiving the antenna and may be further provided with means for fixing the antenna on the axially outer surface of the ring. The means may include a circumferential groove with protrusion since ensuring the positive fixing of the antenna cable such that it can be snap-fitted into the groove in a simple way. In cases where the assembly is not provided with a self-energizing function, the groove or channel may be used to guide an electric cable and/or a signal line from the outside to the inside, or vice versa. In this case, the ring is preferably the non-rotating ring of the bearing. Further, it is proposed that the cylindrical portion includes a sleeve and that two radial portions are independent parts each fastened to the outer surface of the slave. The spacer length and/or the inner diameter and/or the outer diameter of the sleeve can be adjusted as a function of the assembly design or intended field of application, whereas the other parts of the cartridge may be standardized . Preferably, the cylindrical portion and/or at least one of the radial portions is made in a plastic or polymer material.

Further, it is proposed that at least one of the radial portions is overmoulded on to the outer surface of the cylindrical portion or that at least one of the radial portions is press-fitted onto the outer surface of the cylindrical portion.

Preferably, the seal in between the two radial portions consists in a flange, the actual sealing lip being overmoulded or vulcanized onto the flange. In this case, the seal rubber material/layer preferably covers one side of the flange, facing the electronic components in order to protect the space receiving the electronic incensing components from electrostatic discharging.

Preferably, the sealing material is nitrile. The sealing lips and the sealing layer may be formed in one injection moulding step and be formed as a unique seal or may consist in two distinct parts formed in two steps.

Further, it is proposed that the passage or channel for the antenna or cable passes through the seal such that it is kept sealed thanks to the sealing rubber. Further, it is possible that a portion of the antenna is overmoulded onto the fixing ring.

Further, it is proposed that the flange supporting the seal comprises an outer cylindrical portion surrounding the interior components including the sensor, the seals and the sleeve as well as eventually magnetic devices or encoder rings and that the outer cylindrical portion of the flange comprises inwardly bent skirts avoiding an axial movement of the flange. Preferably, the axial movement is limited in such a way that the seal deformation in the course of axial movements within the limited range does not damage the seal. Further, it is proposed that at least one of the parts, preferably the flange supporting the seal, is provided with an anti-rotation structure such as a rubber ring, which is preferably overmoulded onto a portion of the cartridge part or flange supporting the seal. Further, the radial portion may comprise a contactless deflector directed towards the flange and the other part of the cartridge.

The cartridge may be arranged between an inner and an outer ring if the bearing is sufficiently large or attached to the respective axial end faces of the inner ring and the outer ring .

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.

The sealing assembly 20 is fitted over the shaft 12, 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. 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 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. 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 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. 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. 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, wherein 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 .

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.

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.

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 encoder ring 26 is fitted into the outer flange 34 and fixed thereto with pins 48. 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.

In all the embodiments of above, the Hall sensor may be used as or replaced by an energy harvester with a capacity sufficient to drive the electronic components mounted on the PCB 30. 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 PCB. A connector may be provided in 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 comprising a sensor arrangement and including a first part (11) and a second part (21), so as to be rotatable relative to one another,

characterized in that the first part (11) and the second part (21) of the assembly are pre-assembled so as to form a compact cartridge which can be mounted as one single component, wherein :

- an encompassing part (11) out of said first part (11) and said second part (21) comprises a cylindrical portion (22) and at least two radial portions (24, 40) radially protruding from the cylindrical portion (22) respectively, and

- the other one of said first part (11) and said second part (21) is an engaging part (21) and comprises at least one portion (34, 36) protruding radially in a direction opposite to the two radially protruding portions (24, 40) of the encompassing part (11) up to a diameter exceeding the end diameter of the two radial portions (24, 40) in their protruding direction such that the one radial portion (34, 36) meshes with the at least two radial portions (24, 40).

Sealing assembly according to claim 1,

characterized in that the first part (11) is configured to be connected to a first ring of a bearing (14b) and the second part (21) is configured to be connected to a second ring of the said bearing (14b), the first and second rings being rotatable relative to one another.

Sealing assembly according to claim 1 or 2,

characterized in that the cylindrical portion includes a sleeve (22), wherein the two radial portions are independent parts (24, 40) each fastened to the radially outer surface of the sleeve. (22).

Sealing assembly according to any of the preceding claims,

characterized in that a sealing lip (36) is provided between the two radial portions.

5. Sealing assembly according to claim 4, characterized in that the seal includes a sealing lip (36) materially bonded to a flange (34).

6. Sealing assembly according to claim 5,

characterized in that a seal rubber material is provided so as to cover one side of the flange (34) facing the electronic components.

7. Sealing assembly according to claim 6,

characterized in that a passage for a cable passes through the seal such that it is kept sealed by the sealing rubber material .

8. Sealing assembly according to one of claims 5 to 7,

characterized in that the flange (34) supporting the sealing lip (36) comprises an outer cylindrical portion surrounding electronic components of the sensor assembly, wherein the outer cylindrical portion of the flange (34) comprises inwardly bent skirts (64) avoiding an axial movement of the flange (34).

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

characterized in that the force needed to disassemble the two parts

(11, 21) amounts to at least 10 N, preferably 100 N or more.

10. 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).

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

characterized by comprising generator means (26) for generating energy for self-powering electronic devices of the sensor assembly.

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

characterized in that the sensor assembly includes 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) is closed in the absence of external forces and upon transporting and handling the cartridge.

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

characterized by further including a ring (44; 22) having a channel suitable for receiving an electrical cable connected to electronic components of the sensor assembly.

14. Sealing assembly according to claim 13,

characterized in that the ring (44, 22) provided with a channel designed to be the rotating ring .

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

characterized in that at least one of the parts (11, 21) is provided with an anti-rotation structure (52).