Sealing device

A sealing device includes a metal core configured to be attached to a stationary member of a bearing mechanism, an annular slinger configured to be attached to a rotary member of the bearing mechanism, a seal member attached to the metal core, and a discharge body. The discharge body includes a base having discharge holes, an attachment that is continuous with the base and attached to the slinger, and fins protruding from the base. The discharge body is configured to be rotated together with the slinger. A communication space surrounded by the slinger and the seal member is configured to communicate with an external space of the bearing mechanism via an opening. At least the fins of the discharge body are positioned in the communication space. When the rotary member rotates, an inflow flowed into the communication space is moved by the fins toward the external space.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims priority from Japanese Patent Application No. 2020-178338 filed on Oct. 23, 2020, the entire contents of which are hereby incorporated by reference.

BACKGROUND

The disclosure relates to a technical field about a sealing device to be used in a bearing mechanism of a vehicle.

In vehicles such as automobiles, bearing mechanisms are used to ensure stable rotation of rotational parts. For example, a hub bearing is disposed as a bearing mechanism in a support unit of a vehicle wheel.

The hub bearing includes an outer race and an inner race. The outer race is a stationary member configured to be fixed to a vehicle body. The inner race is a rotary member to which a vehicle wheel is to be attached. The inner race is supported by the outer race so as to be rotatable around an axis. In the hub bearing, rollers that are in contact with the outer race and the inner race are disposed between these races. The inner race can smoothly rotate relative to the outer race as the rollers are rolled.

However, with the hub bearing described above, for example, if an inflow such as mud or dust splashed by a vehicle wheel during driving enters the inside of the hub bearing from a gap between the outer race and the inner race and reaches the rollers, malfunctioning or a failure of the bearing mechanism may occur.

It may be possible to prevent entry of an inflow by sealing the gap between the outer race and the inner race by providing the outer race with a seal member that contacts the inner race. In this case, however, as the contact area between the seal member and the inner race increases, rotational resistance increases, and the performance of the bearing mechanism may decrease. Therefore, in general, the hub bearing includes, in the gap between the outer race and the inner race at an end of the hub bearing, a sealing device for preventing entry of an inflow in a state in which the contact area between the seal member and the rotary member is reduced.

Among sealing devices configured as described above, there is a known sealing device that prevents entry of an inflow into a space in a bearing mechanism further inside than the sealing device by holding back the inflow in a communication space in the sealing device and causes the inflow that has been held back to flow out to an external space of the bearing mechanism by using rotation of the inner race (see, for example, Japanese Unexamined Patent Application Publication No. 2015-86993).

SUMMARY

An aspect of the disclosure provides a sealing device to be used in a bearing mechanism. The sealing device includes a metal core, an annular slinger, a seal member, and a discharge body. The metal core is configured to be attached to a stationary member of the bearing mechanism. The annular slinger is configured to be attached to a rotary member of the bearing mechanism and to be rotated together with the rotary member. The seal member is attached to the metal core and includes a contact including a part that is in contact with the slinger. The discharge body includes an annular base that has discharge holes that are separated from each other in a circumferential direction, an attachment that is continuous with the base and attached to the slinger, and fins that protrude from the base and are positioned separated from each other in the circumferential direction. The discharge body is configured to be rotated together with the slinger. A space surrounded by the slinger and the seal member is a communication space that is configured to communicate with an external space of the bearing mechanism via an opening. At least the fins of the discharge body are positioned in the communication space. When the rotary member rotates, an inflow flowed into the communication space is moved by the fins toward the external space.

DETAILED DESCRIPTION

In a sealing device, if an inflow does not sufficiently flow out to an external space of a bearing mechanism and the inflow amount of an inflow that flows into a communication space exceeds the outflow amount, it may not be possible to hold back the inflow in the communication space and the inflow may enter a space in the bearing mechanism further inside than the sealing device.

It is desirable to ensure good operating conditions of a bearing mechanism by preventing entry of an inflow to a space in the bearing mechanism further inside than a sealing device.

Structure of Bearing Mechanism

First, the schematic structure of a bearing mechanism100including a sealing device will be described (seeFIG.1).

The bearing mechanism100includes an outer race101that is fixed to a vehicle body and an inner race102that is rotatable relative to the outer race101.

The outer race101has a cylindrical shape and is a stationary member that is fixed to a support unit (not illustrated) of a vehicle.

The inner race102is composed of a hub103and a coupling ring104, each of which has an annular shape. The inner race102is a rotary member that is rotated in accordance with the rotation of a drive shaft200that is coupled to a differential mechanism (not illustrated), a propeller shaft (not illustrated), or the like. The hub103includes a body105having a cylindrical shape and a hub flange106that protrudes outward from the body105. The inner race102is held by the drive shaft200as a nut201is fastened to the drive shaft200inserted through the body105, and is rotated in accordance with the rotation of the drive shaft200. Bolts107are inserted through the hub flange106in a state in which the bolts107are separated from each other in the circumferential direction. A vehicle wheel (not illustrated) is attached to the inner race102by using the bolts107. The coupling ring104is coupled to an end of the body105on the vehicle body side.

Between the outer race101and the inner race102, rollers108are disposed separated from each other in the circumferential direction in a state in which the rollers108are held by a cage109. In the bearing mechanism100, the inner race102is smoothly rotated relative to the outer race101as the rollers108are rolled when the inner race102rotates.

A sealing device1is disposed between the outer race101and the coupling ring104at an end of the bearing mechanism100on the vehicle body side. A sealing member110having, for example, a labyrinthine structure is attached to an end of the outer race101on the vehicle wheel side. The sealing member110seals the gap between the outer race101and the inner race102.

Structure of Sealing Device

Next, the structure of the sealing device1will be described (seeFIGS.2to4).

The sealing device1has a substantially annular shape as a whole and includes a metal core2attached to the outer race101, a slinger3attached to the coupling ring104, a seal member4attached to the metal core2, and a discharge body5attached to the slinger3(seeFIG.2).

The metal core2includes an annular portion6that faces in the axial direction of the drive shaft200and a first tubular portion7that protrudes from an outer peripheral edge of the annular portion6toward the vehicle body side. A space inside of the annular portion6is an insertion hole6athat extends through the annular portion6in the axial direction. An outer peripheral surface of the first tubular portion7of the metal core2is fixed to the outer race101.

The slinger3includes a second tubular portion8whose central axis coincides with the rotation axis of the drive shaft200and a flange9that protrudes outward from an end of the second tubular portion8on the vehicle body side. An inner peripheral surface of the second tubular portion8is fixed to the coupling ring104. Accordingly, the slinger3rotates together with the inner race102in accordance with rotation of the drive shaft200.

The slinger3is disposed on the inner peripheral side of the first tubular portion7in a state in which an end of the second tubular portion8is inserted through the insertion hole6aof the annular portion6. The flange9of the slinger3is positioned separated from the annular portion6in the axial direction.

The seal member4is made of an elastic material and includes a seal base10that is attached along the inside of the metal core2and a contact11and a lip12each of which extends from the seal base10. The contact11protrudes from an inner peripheral edge of the seal base10toward the second tubular portion8side, and a distal end of the contact11is pressed against the outer peripheral surface of the second tubular portion8by an elastic force. The lip12is positioned further toward the outer peripheral side than the contact11in the radial direction, and protrudes toward the flange9. A distal end of the lip12is positioned separated from the flange9.

A space surrounded by the slinger3and the seal member4is a communication space13. The communication space13communicates with an external space300of the bearing mechanism100via an opening14formed in the outside of an outer peripheral edge of the flange9.

The discharge body5includes a base15, an attachment16, and a plurality of fins17(seeFIGS.2to4). The attachment16of the discharge body5is attached to the slinger3, and the discharge body5is rotated together with the slinger3in accordance with rotation of the inner race102. For example, when the vehicle moves forward, the discharge body5is rotated in a rotation direction R illustrated inFIG.3. The discharge body5is made of, for example, a resin material.

The base15includes a peripheral portion18whose central axis coincides with the rotation axis of the drive shaft200and a pair of side portions19that respectively extend inward from both ends in the axial direction of the peripheral portion18. The peripheral portion18has discharge holes20that extend through the peripheral portion18in the radial direction and that are separated from each other in the circumferential direction of the discharge body5. The discharge holes20each have a rectangular shape whose longitudinal direction is the width direction of the peripheral portion18.

The attachment16includes a mating-face portion21that protrudes in the vehicle-body direction from an end of the peripheral portion18of the base15on the vehicle body side and a pressing ring22that is attached to the mating-face portion21. The mating-face portion21has an inside diameter substantially the same as the outside diameter of the flange9and is fitted onto the flange9. The mating-face portion21has attachment pins23that protrude toward the vehicle body side and are separated from each other in the circumferential direction. The pressing ring22has an outside diameter substantially the same as the outside diameter of the mating-face portion21. Attachment holes22aare formed in an outer peripheral part of the pressing ring22at positions corresponding to the attachment pins23.

As the attachment pins23of the discharge body5are press-fitted into the attachment holes22ain a state in which the mating-face portion21is fitted onto the flange9, the discharge body5is attached to the slinger3in a state in which the flange9is held between one of the side portions19of the base15and the pressing ring22. Accordingly, the base15is disposed near the opening14in the communication space13and is positioned further toward the outer peripheral side than the lip12of the seal member4.

The pressing ring22may be attached to the mating-face portion21by forming distal ends of the attachment pins23as engagement hooks to be engaged with the pressing ring22and by engaging the attachment pins23with the pressing ring22in a state in which the attachment pins23are inserted through the attachment holes22a. Thus, accidental removal of the pressing ring22from the mating-face portion21is prevented, and the discharge body5can be reliably attached to the slinger3.

The fins17are disposed in a state in which the fins17protrude from opening edges of the discharge holes20in the peripheral portion18of the base15(seeFIGS.3and4). Accordingly, the fins17are disposed on the base15in a state in which the fins17are separated from each other in the circumferential direction of the discharge body5.

The fins17each include an inner fin24that protrudes to the inside of the peripheral portion18and an outer fin25that protrudes to the outside of the peripheral portion18(seeFIG.3). The inner fins24and the outer fins25of the fins17are alternately positioned in the circumferential direction of the peripheral portion18.

The inner fin24is inclined so as to be displaced forward in the rotation direction R with decreasing distance from the distal end thereof. The outer fin25is inclined so as to be displaced in the direction opposite to the rotation direction R with decreasing distance from the distal end thereof. Accordingly, the inner fin24and the outer fin25protrude in directions opposite to each other with the peripheral portion18interposed therebetween. A distal end25aof the outer fin25is bent with respect to the other portions in a direction toward the peripheral portion18.

Both ends in the width direction of the inner fin24are coupled to the two side portions19of the base15. Thus, parts of each of the fins17are respectively formed so as to be continuous from the side portions19of the base15. Accordingly, high strength of the fins17can be ensured.

An end in the width direction of each of the fins17on the vehicle wheel side is positioned further forward in the rotation direction R than an end in the width direction of the fin17on the vehicle body side in the circumferential direction of the peripheral portion18(seeFIG.5). Accordingly, each of the fins17is inclined so as to be displaced forward in the rotation direction R with increasing distance from the attachment16in the width direction of the peripheral portion18, and is displaced forward in the rotation direction R with increasing distance from the opening14.

Hereafter, an operation of the sealing device1will be described (seeFIG.4).

When the vehicle moves, for example, forward, an inflow50such as mud or dust splashed by a vehicle wheel may flow into the communication space13from the opening14.

The inflow50flowed into the communication space13flows to the inner peripheral side of the communication space13. Because the contact11, which is pressed against the second tubular portion8, suppresses entry of the inflow50to a space in the bearing mechanism100further inside than the communication space13, the inflow50is retained in the communication space13or flows out again through the opening14toward the external space300of the bearing mechanism100.

At this time, if the inflow50does not flow out sufficiently and the inflow amount into the communication space13becomes greater than the outflow amount or if the inflow50flows into the communication space13with a high speed, the water pressure applied to the contact11may increase, the contact11may become displaced, and the inflow50may enter from a contact portion between the second tubular portion8and the contact11to the inside of a space in the bearing mechanism100further inside than the communication space13. However, in the sealing device1, the discharge body5prevents entry of the inflow50to the space further inside than the communication space13.

In the sealing device1, the inflow50flowed into the communication space13is moved by the slinger3that is rotated together with the inner race102. Moreover, a centrifugal force acts on the inflow50that is being moved, and the inflow50is moved toward the outer peripheral side in the communication space13.

A part of the inflow moved toward the outer peripheral side flows out to the external space300from the opening14. Another part of the inflow50moved toward the outer peripheral side is moved toward the discharge body5that is rotated together with the inner race102. The inflow50moved to the discharge body5is moved along the fins17.

The inflow50moved to the discharge body5is first moved along the inner fins24and then is moved toward the outer peripheral side of the base15through the discharge holes20. The inflow moved to the outer peripheral side of the base15is moved toward the opening14along the outer fins25, and flows out from the opening14toward the external space300. Accordingly, the inflow50can be efficiently moved toward the external space300of the bearing mechanism100.

In the sealing device1described above, an end in the width direction of each of the fins17on the vehicle wheel side is positioned further forward in a rotation direction of the inner race102than an end in the width direction of the fin17on the vehicle body side in the circumferential direction of the peripheral portion18. Thus, the inflow50can be easily moved by the fins17toward the opening14when the discharge body5rotates, and therefore the inflow50can efficiently flow out to the external space300of the bearing mechanism100.

As described above, in the sealing device1, the inflow50flowed into the communication space13is moved by the fins17of the discharge body5that is rotated in accordance with the inner race102, and is moved via the discharge holes20toward the external space300of the bearing mechanism100. Therefore, entry of the inflow50into a space in the bearing mechanism100further inside than the communication space13is prevented, and good operating conditions of the bearing mechanism100can be ensured.

Moreover, in the sealing device1, the discharge body5is rotated in accordance with the rotation of the inner race102. Therefore, a dedicated driving source for rotating the discharge body5is not necessary, and the discharge body5can be reliably rotated with a simple structure when the vehicle wheel rotates (when the vehicle moves).

Furthermore, in the sealing device1, the base15of the discharge body5is positioned in the communication space13, and the lip12of the seal member4is positioned between the contact11and the base15in the communication space13. Thus, the base15and the lip12form a labyrinthine structure in the communication space13, and therefore the flow speed of the inflow50flowing into the communication space13toward the contact11side can be reduced, and the flow amount of the inflow toward the contact11side can be reduced.

In the example of the sealing device1structured as described above, the fins17each include the inner fin24and the outer fin25. However, the fins17may each include only the inner fin24(seeFIG.6).

With the structure in which the fins17each include only the inner fin24, nothing protrudes from the peripheral portion18in the radial direction. Therefore, high strength of the discharge body5can be ensured, the fins17are not likely to interfere with a surrounding member when the discharge body5is assembled in the bearing mechanism100, and the workability of assembly operation can be improved.

In the example described above, an end in the width direction of each of the fins17on the vehicle wheel side is positioned further forward in the rotation direction R of the inner race102than an end in the width direction of the fin17on the vehicle body side in the circumferential direction of the peripheral portion18. However, the fins17may be disposed in the width direction parallel to the axial direction the base15(seeFIG.7).

Furthermore, in the example of the sealing device1described above, the attachment16includes the mating-face portion21and the pressing ring22, the attachment pins23are disposed in the mating-face portion21, and the pressing ring22has the attachment holes22a. However, the attachment pins23may protrude from, instead of the mating-face portion21, the side portion19of the base15on the flange9side, and the flange9may have attachment holes9a(seeFIG.8).

Thus, the discharge body5is attached to the slinger3by press-fitting the attachment pins23into the attachment holes9ain a state in which the mating-face portion21is fitted onto the flange9. Accordingly, the pressing ring22is not necessary, and therefore the number of components can be reduced and the operation of attaching the discharge body5to the slinger3can be simplified.