JP2013224717A - Bearing device for wheel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a bearing device for a wheel capable of improving sealing performance by preventing the entire abutting of a seal lip to improve contact surface pressure of a lip part.SOLUTION: A bearing device for a wheel includes an annular seal plate 14 and a slinger 15. The seal plate 14 comprises a core metal 16 pressed into an outer member 10, and a sealing member 17 joined to the core metal 16 by cure adhesion. The slinger 15 includes a cylindrical part 15a pressed into the outer periphery of an inner ring 3, and an upright plate part 15b extending outward in a radial direction from the cylindrical part 15a. The sealing member 7 includes a side lip 17a brought into slide contact with the upright plate part 16b of the slinger 15 via a predetermined axial interference, and radial lips 17b and 17c brought into slide contact with the cylindrical part 15a via a predetermined radial direction interference. The outer side fade 19 of the upright plate part 15b is formed on the outer side to gradually incline from the end of the cylindrical part 15a outward in the radial direction, and this inclination angle is set equal to or higher than 86.5° to less than 90°.

Description

  The present invention relates to a wheel bearing device that rotatably supports a wheel of an automobile or the like with respect to a suspension device.

  2. Description of the Related Art Conventionally, a wheel bearing device for supporting a wheel of an automobile or the like supports a hub wheel for mounting a wheel rotatably via a double row rolling bearing, and includes a drive wheel and a driven wheel. For structural reasons, an inner ring rotation method is generally used for driving wheels, and an inner ring rotation method and an outer ring rotation method are generally used for driven wheels. Further, the wheel bearing device has a structure called a first generation in which a wheel bearing composed of a double row angular ball bearing or the like is fitted between a knuckle and a hub wheel constituting a suspension device. Second generation structure in which body mounting flange or wheel mounting flange is formed directly on the outer periphery of the member, third generation structure in which one inner rolling surface is directly formed on the outer periphery of the hub wheel, or hub wheel, etc. It is roughly classified into a fourth generation structure in which the inner rolling surface is directly formed on the outer periphery of the outer joint member of the speed universal joint.

  These bearing portions are equipped with a sealing device for preventing leakage of grease sealed in the bearings and preventing intrusion of rainwater, dust and the like from the outside. 2. Description of the Related Art In recent years, maintenance-free automobiles have progressed, and even longer wheel bearing devices have been demanded. For example, the bearing life can be improved by improving the sealing performance of the sealing device in order to prevent the bearing from being damaged due to intrusion of rainwater, dust or the like into the bearing due to a sealing failure or a decrease in sealing performance.

  Conventionally, various sealing devices with improved sealing performance have been proposed. An example of such a sealing device is shown in FIG. The sealing device 51 is provided with a cored bar 52 that is fitted on the inner peripheral side of an outer ring (not shown) as an attachment member, and a rubber-like elastic sealing member 53 is added to the cored bar 52. A plurality of seal lips are integrally formed on the seal member 53, and the plurality of seal lips are fitted on the outer peripheral side of a hub (not shown) which is a relative rotation member in the bearing portion. A side lip 56 slidably in close contact with the axial end surface 55a of the standing plate 55 of the slinger 54 made of a rigid material such as a metal, and slides on the outer peripheral surface 57a of the cylindrical portion (axial portion) 57 of the slinger 54. It is constituted by a dust lip 58 which is freely in close contact.

  Each of the side lip 56 and the dust lip 58 seals foreign matter such as muddy water and dust outside the bearing from entering the inside of the bearing, and has an outward structure because of its function. 56 is formed so that its diameter gradually increases from its proximal end to its distal end.

  Further, the side lip 56 is formed in a cross-sectional linear shape in which the tip surface 56a intersects obliquely (obtuse angle) with respect to the inner peripheral surface 56b, whereby the side lip 56 has a sliding portion tip apex angle. The angle θ1 is larger than 90 degrees and 110 degrees or less (90 ° <θ1 ≦ 110 °, for example, about 100 °). The sliding portion tip apex angle θ <b> 1 is an angle formed by the tip end surface 56 a of the side lip 56 and the inner peripheral surface 56 b in the cross-sectional shape of the side lip 56.

  When the sealing device 51 having such a configuration is mounted on an actual machine, the slinger 54 is displaced in the axial direction relative to the side lip 56 and the size of the side lip 56 with respect to the slinger 54 changes, The slinger 54 is displaced in the radial direction (perpendicular to the axis) relative to the side lip 56 to cause axial eccentricity, or the slinger 54 is oscillated and displaced relative to the side lip 56 so-called surface. Although vibration may occur or they may occur in combination, this sealing device 51 is characterized in that it has the following operational effects by the above-described configuration.

  That is, in the sealing device 51, since the tip angle θ1 of the sliding portion of the side lip 56 is formed at an angle larger than 90 degrees, the volume at the tip of the side lip 56 is substantially increased as compared with the prior art. ing. This is because the front end surface 56a of the side lip 56 is formed in a shape protruding in the front end direction (longitudinal direction) of the side lip 56, as compared with the case where the sliding portion apex angle is 90 degrees or less. .

  That is, since the side lip 56 is not easily deformed and the contact state thereof is stable, the stress distribution of the side lip 56 can be properly maintained even under adverse conditions such as a change in the surface and the occurrence of surface runout. Can do. Therefore, the contact surface pressure peak value of the side lip 56 can be prevented from becoming extremely small and the sealing performance can be prevented from being extremely lowered, whereby the sealing performance can be stabilized. Further, if the contact state of the tip of the side lip 56 is stabilized, it is possible to prevent the tip of the side lip 56 from being lifted, so that the sealing performance can be stabilized also from this point (see, for example, Patent Document 1). .

JP 2005-90526 A

  When strong contact occurs between the side lip 56 and the standing plate portion 55 of the slinger 54, the side lip 56 becomes solid and the contact surface pressure is lowered, the sealing performance is lowered, and muddy water is likely to enter from the outside. Become. In such a conventional sealing device 51, in order to avoid a decrease in the contact surface pressure, the apex angle θ1 of the tip surface 56a is increased, and the rigidity is increased to suppress the contact surface pressure and maintain a constant surface pressure. Trying to maintain high sealing performance.

  However, as schematically shown in FIG. 12, when the contact between the side lip 56 and the upright plate portion 55 of the slinger 54 becomes strong, the upright plate portion 55 is perpendicular to the center of the bearing. As a result, the sliding contact width increases and becomes solid, and as a result, the contact area increases and the contact surface pressure may decrease. As shown in FIG. 13, when the tip surface 56a of the side lip 56 has a V shape as shown in FIG. 13, the inner peripheral surface 56b becomes a solid contact, and the contact area may increase and the contact surface pressure may decrease. is there.

  The present invention has been made in view of such circumstances, and provides a wheel bearing device that prevents the seal lip from becoming solid and improves the sealing performance by increasing the contact surface pressure of the lip portion. The purpose is to do.

  In order to achieve such an object, the invention according to claim 1 of the present invention includes an outer member in which a double row outer rolling surface is integrally formed on the inner periphery, and a wheel attachment for attaching a wheel to one end. The hub ring has a flange integrally formed with a small diameter step portion extending in the axial direction on the outer periphery, and at least one inner ring press-fitted into the small diameter step portion of the hub ring. An inner member in which a double-row inner rolling surface facing the running surface is formed, and a double-row rolling element that is movably accommodated between the inner and outer members. And a seal for sealing both side openings of an annular space formed between the outer member and the inner member, wherein at least one of the seals is the outer seal. Cylindrical fitting that is press-fitted into the inner periphery of the end of the one-way member via a predetermined scissors And an inner diameter portion extending radially inward from the end of the fitting portion, and a cored bar formed by pressing from a steel plate and a synthetic rubber integrally joined to the cored bar by vulcanization adhesion A sealing member, and the sealing member has a side lip that is inclined and extends radially outward, and the side lip is slidably contacted with the mating member via an axial shimiro, and the sliding surface of the mating member However, it is inclined at an angle of 86.5 ° or more and less than 90 ° toward the side lip toward the outside in the radial direction.

  Thus, in the wheel bearing device including the seal that seals both side openings of the annular space formed between the outer member and the inner member, at least one of the seals is the outer member. A metal core formed of a steel plate by press working, comprising a cylindrical fitting portion that is press-fitted into the inner periphery of the end portion via a predetermined shimiro and an inner diameter portion that extends radially inward from the end portion of the fitting portion. And a sealing member made of synthetic rubber integrally joined to the metal core by vulcanization adhesion, and the sealing member has a side lip extending obliquely outward in the radial direction, and the side lip is a counterpart member Since the sliding contact surface of this mating member is formed so as to be inclined at an angle of 86.5 ° or more and less than 90 ° toward the side lip toward the outer side in the radial direction. The sliding surface of the lip is solid Thus, it is possible to provide a wheel bearing device in which the sealing performance is improved by preventing contact and increasing the contact surface pressure of the lip portion.

  Preferably, as in the invention described in claim 2, if the inner peripheral surface of the side lip is formed in a concave shape having a predetermined radius of curvature, the sliding contact surface of the side lip is solid. It can be surely prevented, and the contact surface pressure of the lip portion can be increased to further improve the sealing performance.

  Moreover, if the curvature radius of the inner peripheral surface of the side lip is set in a range of 1.0 to 3.0 times the length of the side lip, as in the invention described in claim 3, The tip angle does not become an acute angle, a stable shape is obtained, and a desired sealing property can be maintained over a long period of time.

  According to a fourth aspect of the present invention, the seal on the outer side of the seal is constituted by an integral seal composed of the core metal and the seal member, and the seal member is an inner member of the wheel mounting flange. A side lip that is in sliding contact with the side surface on the side, and a dust slidable contact with a base of the inner side of the wheel mounting flange that is formed in an arc shape with a predetermined axial direction incline toward the inner side of the bearing, A grease lip that is slidably contacted with a predetermined radial squeeze at the base of the inner side of the wheel mounting flange is integrally formed, and the side surface of the inner side of the wheel mounting flange is gradually inclined radially outward toward the inner side. It may be formed.

  Further, as in the invention described in claim 5, the inner peripheral surface of the dust lip may be formed in a concave shape having a predetermined radius of curvature.

  According to a sixth aspect of the present invention, the seal is composed of a pack seal composed of an annular seal plate and a slinger that are substantially L-shaped in cross section and arranged to face each other, and the seal plate The slinger has a cylindrical portion press-fitted into the outer periphery of the inner ring, and a standing plate portion extending radially outward from the cylindrical portion, and the sealing member is the slinger A side lip that is in sliding contact with the vertical plate portion and a radial lip that is in sliding contact with the cylindrical portion, and the side surface of the slinger is formed to be gradually inclined radially outward from the end of the cylindrical portion. good.

  Further, as in the invention according to claim 7, the end portion of the fitting portion of the cored bar is formed to be thin, and the seal member wraps and is joined so as to cover the end portion, thereby forming a half metal structure. If it is made, the inside of the bearing can be protected by improving the airtightness of the fitting portion.

  If grease is applied to the sliding contact portion of the seal lip as in the invention described in claim 8, the lip wear is prevented and durability is improved, and the friction torque is reduced, so that the seal Rotational torque can be reduced. Moreover, since the inner peripheral surface is formed in a concave shape, the grease can be stably held, and the above-described effects can be maintained over a long period of time.

  The wheel bearing device according to the present invention integrally has an outer member integrally formed with a double row outer rolling surface on the inner periphery, and a wheel mounting flange for mounting the wheel on one end, and on the outer periphery. A hub ring formed with a small-diameter step portion extending in the axial direction, and at least one inner ring press-fitted into the small-diameter step portion of the hub ring, the inner side of the double row facing the outer rolling surface of the double row on the outer periphery An inner member having a rolling surface, a double row rolling element housed between the inner member and the outer member so as to roll freely, and the outer member and the inner member. And a seal for sealing both side openings of the annular space formed between the members, and at least one of the seals is provided on the inner periphery of the end of the outer member. Cylindrical fitting part press-fitted through a shimoshiro, and the end of this fitting part An inner diameter portion extending radially inward from the steel plate and formed by pressing from a steel plate, and a seal member made of synthetic rubber integrally joined to the core by vulcanization adhesion. Has a side lip that extends obliquely outward in the radial direction, and the side lip is slidably contacted with the mating member via an axial shimiro, and the slidable contact surface of the mating member is directed radially outward. Since the side lip is inclined at an angle of 86.5 ° or more and less than 90 °, the sliding contact surface of the side lip is prevented from becoming solid and the contact surface pressure of the lip is increased to improve the sealing performance. An improved wheel bearing device can be provided.

It is a longitudinal section showing a 1st embodiment of a bearing device for wheels concerning the present invention. It is a principal part enlarged view which shows one seal | sticker of FIG. It is a principal part enlarged view which shows the other seal | sticker of FIG. It is a schematic diagram which shows the contact state of the slinger and seal lip of FIG. It is a schematic diagram which shows the modification of FIG. It is a longitudinal cross-sectional view which shows 2nd Embodiment of the wheel bearing apparatus which concerns on this invention. It is a principal part enlarged view which shows one seal | sticker of FIG. It is a principal part enlarged view which shows the other seal | sticker of FIG. It is a schematic diagram which shows the contact state of the slinger and seal lip of FIG. It is a schematic diagram which shows a contact state in case the contact force of the seal lip of FIG. 8 is large. It is a principal part enlarged view which shows the sealing device of the conventional wheel bearing. It is a schematic diagram which shows the contact state of the slinger and seal lip of FIG. It is a schematic diagram which shows the modification of FIG.

  An outer member integrally having a vehicle body mounting flange to be attached to the vehicle body on the outer periphery, a double row outer rolling surface formed integrally on the inner periphery, and a wheel mounting flange for mounting a wheel on one end A hub wheel integrally formed and having an inner rolling surface facing one of the outer rolling surfaces of the double row on the outer periphery, and a small-diameter step portion extending in the axial direction from the inner rolling surface, and the hub wheel An inner member formed of an inner ring that is press-fitted into a small-diameter step portion and has an inner rolling surface that is opposed to the other outer rolling surface of the double row on the outer periphery, and each of the inner member and the outer member A double row rolling element housed between the rolling surfaces, and a seal for sealing both side openings of the annular space formed between the outer member and the inner member. In the wheel bearing device, the inner seal of the seals has a substantially L-shaped cross section. A pack seal composed of an annular seal plate and a slinger formed opposite to each other, and the slinger is a cylindrical portion press-fitted into the outer periphery of the inner ring, and a standing portion extending radially outward from the cylindrical portion. The seal plate includes a core metal that is press-fitted into the inner periphery of the end of the outer member, and a seal member that is integrally joined to the core metal by vulcanization adhesion. A side lip that slidably contacts the standing plate portion of the slinger through a predetermined axial shimillo; and a radial lip that slidably contacts the cylindrical portion via a predetermined radial shimillo; The side surface is formed to be gradually inclined outward from the end of the cylindrical portion toward the outer side in the radial direction, and the inner peripheral surface of the side lip is not straight but has a concave shape having a predetermined radius of curvature. It has been made.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
1 is a longitudinal sectional view showing a first embodiment of a wheel bearing device according to the present invention, FIG. 2 is an enlarged view of a main part showing one seal of FIG. 1, and FIG. 3 is the other of FIG. FIG. 4 is a schematic view showing a contact state between the slinger and the seal lip of FIG. 3, and FIG. 5 is a schematic view showing a modification of FIG. In the following description, the side closer to the outer side of the vehicle when assembled to the vehicle is referred to as the outer side (left side in FIG. 1), and the side closer to the center is referred to as the inner side (right side in FIG. 1).

  This wheel bearing is called the third generation on the drive wheel side, and the inner member 1 and the outer member 10, and the double row rolling elements (balls) 6 accommodated between the members 1 and 10 so as to roll freely. , 6. The inner member 1 includes a hub ring 2 and an inner ring 3 press-fitted into the hub ring 2.

  The hub wheel 2 integrally has a wheel mounting flange 4 for mounting a wheel (not shown) at an end on the outer side, and a hub bolt for fixing the wheel at a circumferentially equidistant position of the wheel mounting flange 4. 5 is planted. Further, one (outer side) inner rolling surface 2a and a cylindrical small-diameter step portion 2b extending in the axial direction from the inner rolling surface 2a are formed on the outer periphery of the hub wheel 2, and serrations ( Or a spline) 2c is formed. The inner ring 3 is formed with the other (inner side) inner raceway surface 3a on the outer periphery, and is press-fitted into the small-diameter step portion 2b of the hub ring 2 through a predetermined squeeze.

  The hub wheel 2 is formed of medium and high carbon steel containing 0.40 to 0.80% by weight of carbon such as S53C, and includes a base portion 11 on the inner side of the wheel mounting flange 4 serving as a seal land portion of the seal 8 described later, The surface hardness is set to a range of 58 to 64 HRC by induction hardening from the inner side rolling surface 2a on the outer side to the small diameter step portion 2b. As a result, not only the wear resistance of the base 11 of the wheel mounting flange 4 is improved, but also sufficient mechanical strength against the rotational bending load applied to the wheel mounting flange 4 is obtained. Strength and durability are improved. On the other hand, the inner ring 3 and the rolling element 6 are made of high carbon chrome bearing steel such as SUJ2, and are hardened in the range of 58 to 64 HRC up to the core by quenching.

  The outer member 10 integrally has a vehicle body mounting flange 10b for mounting to a vehicle body (not shown) on the outer periphery, and a double row facing the inner rolling surfaces 2a, 3a of the inner member 1 on the inner periphery. The outer rolling surfaces 10a and 10a are integrally formed. The outer member 10 is formed of medium and high carbon steel containing 0.40 to 0.80 wt% of carbon such as S53C, like the hub wheel 2, and at least the double row outer raceway surfaces 10 a and 10 a are formed by induction hardening. The surface hardness is set in the range of 58 to 64 HRC. And the double row rolling elements 6 and 6 are accommodated between each rolling surface 10a, 2a and 10a, 3a, and these double row rolling elements 6 and 6 are rollably hold | maintained by the holder | retainers 7 and 7. ing. Seals 8 and 9 are attached to the opening of the annular space formed between the outer member 10 and the inner member 1, and leakage of lubricating grease sealed inside the bearing and rainwater and dust from the outside. Etc. are prevented from entering the inside of the bearing.

  In addition, although the wheel bearing apparatus comprised by the double row angular contact ball bearing which used the ball for the rolling element 6 was illustrated here, it is not restricted to this, The double row tapered roller bearing which used the tapered roller for the rolling element 6 It may consist of. In addition, here, a third generation structure in which the inner raceway surface 2a is formed directly on the outer periphery of the hub wheel 2 is illustrated, but although not shown, a pair of inner rings are press-fitted and fixed to the small-diameter step portion of the hub wheel. It may be a first generation or second generation structure.

  In the present embodiment, as shown in an enlarged view in FIG. 2, the seal 8 on the outer side is an integrated sealing device including a metal core 12 and a seal member 13 that is integrally vulcanized and bonded to the metal core 12. It consists of The core 12 is made of a ferritic stainless steel plate (JIS standard SUS430 or the like), an austenitic stainless steel plate (JIS standard SUS304 or the like), or a rust-proof cold rolled steel plate (JIS standard SPCC system or the like). A cylindrical fitting portion 12a having a substantially L-shaped cross section by press working and press-fitted to the inner periphery of the outer side end of the outer member 10 via a predetermined shimoshiro, and the fitting portion 12a And an inner diameter portion 12b extending inward in the radial direction from the end portion of the first. And the sealing member 13 wraps around and joins so that the outer surface ranging from the internal diameter part 12b to the fitting part 12a may be comprised, and has comprised what is called a half metal structure. Thereby, the airtightness of the fitting part 12a can be improved and the inside of a bearing can be protected.

  On the other hand, the seal member 13 is made of synthetic rubber such as NBR (acrylonitrile-butadiene rubber), and extends incline radially outward, and is slidably contacted with the side surface 4a on the inner side of the wheel mounting flange 4. A dust lip 13b that is slidably contacted with the base 11 of the wheel mounting flange 4 formed in an arc shape and a grease lip 13c that extends obliquely inwardly of the bearing are integrally provided. As the material of the seal member 13, in addition to the exemplified NBR, for example, HNBR (hydrogenated acrylonitrile butadiene rubber), EPDM (ethylene propylene rubber), etc. having excellent heat resistance, heat resistance, chemical resistance, etc. Examples thereof include ACM (polyacrylic rubber), FKM (fluororubber), and silicon rubber, which are excellent in the above.

  Here, the side surface 4a on the inner side of the wheel mounting flange 4 is formed so as to be gradually inclined toward the inner side toward the outside in the radial direction, not at a right angle to the shaft center. The inclination angle θ is set to 86.5 ° or more and less than 90 ° (86.5 ° ≦ θ <90 °). Thereby, it is possible to provide a wheel bearing device in which the side lip 13a is prevented from becoming solid and the contact surface pressure of the lip portion is increased to improve the sealing performance. In consideration of lip squeezing, an inclination angle θ of less than 86.5 ° is not preferable because the shimeshiro may increase and promote heat generation and uneven wear. Further, when the angle is 90 ° or more, the entrance of the labyrinth seal 18 described later is opened, so that it is easy for muddy water to enter, and the angle between the lip and the slinger is reduced to prevent the lip from sticking.

  Further, as shown in an enlarged view in FIG. 3, the inner side seal 9 is a so-called pack seal composed of an annular seal plate 14 and a slinger 15 having a substantially L-shaped cross section and arranged to face each other. It constitutes a so-called composite type seal.

  The annular seal plate 14 includes a cored bar 16 press-fitted into the inner periphery of the inner side end of the outer member 10, and a seal member 17 integrally vulcanized and bonded to the cored bar 16. The core metal 16 is formed from a ferritic stainless steel plate, an austenitic stainless steel plate, or a cold-rolled steel plate that has been rust-proofed by pressing to have a substantially L-shaped cross section, and is formed on the inner periphery of the end of the outer member 10. It has a cylindrical fitting portion 16a that is press-fitted through a predetermined shimoshiro, and an inner diameter portion 16b that extends radially inward from the end of the fitting portion 16a. And the front-end | tip part of the fitting part 16a of the metal core 16 is formed thinly, and the sealing member 17 wraps around and joins so that this front-end | tip part may be covered, and has comprised what is called a half metal structure.

  On the other hand, the slinger 15 is formed into a substantially L-shaped section by pressing from a ferritic stainless steel plate, an austenitic stainless steel plate, or a cold-rolled steel plate that has been rust-proofed, and is press-fitted into the outer peripheral surface of the inner ring 3. A cylindrical portion 15a, and a standing plate portion 15b extending radially outward from the cylindrical portion 15a. The outer edge of the standing plate portion 15b of the slinger 15 is opposed to the seal member 14 through a slight radial clearance to form a labyrinth seal 18.

  The seal member 17 is made of synthetic rubber such as NBR, and has a side lip 17a that is in sliding contact with an outer side surface 19 of the standing plate portion 15b of the slinger 15 via a predetermined axial squeeze, and a fork on the inner diameter side of the side lip 17a. And a grease lip 17c and a dust lip 17b that are in sliding contact with the outer peripheral surface of the cylindrical portion 15a of the slinger 15 via a predetermined radial scissors.

  Here, the standing plate portion 15b of the slinger 15 with which the side lip 17a is slidably contacted is not formed at a right angle with respect to the axial center, but is gradually inclined from the end of the cylindrical portion 15a toward the inner side in the radial direction. Yes. The inclination angle θ is set to 86.5 ° or more and less than 90 ° (86.5 ° ≦ θ <90 °).

  FIG. 4 schematically shows a contact state between the slinger 15 and the side lip 17a. As can be seen from this, when the contact between the side lip 17a and the standing plate portion 15b of the slinger 15 becomes strong, the standing plate portion is not perpendicular to the bearing center as in the prior art, but is inclined so as to have a slightly acute angle. As a result, the inner peripheral surface 20 of the side lip 17a is not solid and the sliding contact width L is substantially shortened. As a result, the contact area increases and the contact surface pressure decreases. Can be prevented. In the case where the front end surface 17aa of the side lip 17a is V-shaped as shown in FIG. 5, the inner peripheral surface 20 is not solid and the contact area increases and the contact surface pressure decreases. Can be prevented.

  6 is a longitudinal sectional view showing a second embodiment of the wheel bearing device according to the present invention, FIG. 7 is an enlarged view of a main part showing one seal of FIG. 6, and FIG. 8 is the other of FIG. FIG. 9 is a schematic view showing a contact state between the slinger and the seal lip of FIG. 8, and FIG. 10 is a schematic view showing a contact state when the contact force of the seal lip of FIG. 8 is large. is there. Note that this embodiment is basically the same as the above-described embodiment (FIG. 1) except that the seal and the sliding contact portion of the seal are different, and other parts and parts having the same or similar functions. Are denoted by the same reference numerals, and detailed description thereof is omitted.

  This wheel bearing is referred to as a third generation on the drive wheel side, and includes an inner member 21 and an outer member 10, and double row rolling elements 6 and 6 accommodated between the members 1 and 10 so as to roll freely. It has. The inner member 21 includes a hub ring 22 and an inner ring 3 press-fitted into the hub ring 22.

  The hub wheel 22 integrally has a wheel mounting flange 4 at an end portion on the outer side, and a hub bolt 5 for fixing the wheel at a circumferentially equidistant position of the wheel mounting flange 4 is implanted. Further, one (outer side) inner rolling surface 2a and a cylindrical small-diameter step portion 2b extending in the axial direction from the inner rolling surface 2a are formed on the outer periphery of the hub wheel 22, and the serration 2c is formed on the inner periphery. Is formed. The inner ring 3 is formed with the other (inner side) inner raceway surface 3a on the outer periphery, and is press-fitted into the small-diameter step portion 2b of the hub ring 2 through a predetermined squeeze.

  The hub wheel 22 is formed of medium and high carbon steel containing 0.40 to 0.80% by weight of carbon such as S53C, and includes the base portion 11 on the inner side of the wheel mounting flange 4 serving as a seal land portion of the seal 23 described later. The surface hardness is set to a range of 58 to 64 HRC by induction hardening from the inner side rolling surface 2a on the outer side to the small diameter step portion 2b.

  Seals 23 and 24 are attached to the opening portion of the annular space formed between the outer member 10 and the inner member 21, and leakage of lubricating grease sealed inside the bearing, rainwater, dust, etc. from the outside. It prevents entry into the bearing.

  In the present embodiment, the outer-side seal 23 is an integral seal comprising a cored bar 12 and a seal member 25 integrally vulcanized and bonded to the cored bar 12, as shown in an enlarged view in FIG. It is configured. The seal member 25 is made of a synthetic rubber such as NBR, extends in a radially outward direction, and has a side lip 25a slidably in contact with the side surface 4b on the inner side of the wheel mounting flange 4 and a cross section formed in an arc shape. A dust lip 25b slidably in contact with the base portion 11 of the wheel mounting flange 4 and a grease lip 25c extending incline toward the bearing inward side are integrally provided. In addition to the exemplified NBR, examples of the material of the seal member 25 include HNBR, EPDM, etc., which are excellent in heat resistance, and ACM, FKM, silicon rubber, etc., which are excellent in heat resistance and chemical resistance. can do.

  Here, the side lip 25a is not straight, and the inner peripheral surface 26 is formed in a concave shape having a predetermined radius of curvature R1. Similarly, the inner peripheral surface 27 of the dust strip 25b is formed in a concave shape having a predetermined radius of curvature R2. Thereby, it is possible to provide a wheel bearing device in which the side lip 25a and the dust lip 25b are prevented from becoming solid and the contact surface pressure of the lip portion is increased to improve the sealing performance.

  The curvature radii R1 and R2 of the inner peripheral surfaces 26 and 27 are set in a range of 1.0 to 3.0 times the lip lengths W1 and W2. When the radii of curvature R1 and R2 are less than the lip lengths W1 and W2, the tip angle becomes too acute when considering the lip shimeoshiro, and it is difficult to manufacture a mold and a stable shape cannot be obtained. There is a risk of promoting. Further, if the curvature radii R1 and R2 exceed 3.0 times the lip lengths W1 and W2, the effect is halved, which is not preferable.

  Further, grease 28 is applied between the side lip 25a and the dust lip 25b and between the dust lip 25b and the grease lip 25c. The grease 16 is the same as the grease sealed for lubricating the bearing portion. Thereby, while preventing lip wear and improving durability, the friction torque can be reduced and the rotational torque of the seal 23 can be reduced. Moreover, since the inner peripheral surfaces 26 and 27 are formed in a concave shape, the grease 28 can be stably held, and the above-described effects can be maintained over a long period of time.

  The grease 28 to be applied may be different from the grease sealed in the bearing portion. In this case, by setting the base oil kinematic viscosity of the grease 28 to be equal to or lower than the base oil kinematic viscosity of the grease sealed in the bearing portion, the friction torque of the lip can be reduced and the rotational torque can be further reduced.

  Further, as shown in an enlarged view in FIG. 8, the inner-side seal 24 is constituted by a pack seal including an annular seal plate 29 and a slinger 30 which are formed in a substantially L-shaped cross section and are arranged to face each other. ing.

  The annular seal plate 29 includes a cored bar 16 press-fitted into the inner periphery of the inner side end of the outer member 10, and a seal member 31 integrally vulcanized and bonded to the cored bar 16. And the front-end | tip part of the fitting part 16a of the metal core 16 is formed thinly, and the sealing member 31 wraps around and joins so that this front-end | tip part may be covered, and has comprised the half metal structure.

  On the other hand, the slinger 30 is formed into a substantially L-shaped section by pressing from a ferritic stainless steel plate, an austenitic stainless steel plate, or a cold-rolled steel plate that has been rust-proofed, and is press-fitted into the outer peripheral surface of the inner ring 3. A cylindrical portion 30a, and a standing plate portion 30b extending radially outward from the cylindrical portion 30a. Note that the outer edge of the standing plate portion 30 b of the slinger 30 faces the opening of the seal plate 29 through a slight radial clearance to constitute the labyrinth seal 18.

  The seal member 31 is made of a synthetic rubber such as NBR, and extends in a radially outward direction. The seal member 31 includes a side lip 31a that slidably contacts the outer side surface 32 of the standing plate portion 30b of the slinger 30 via a predetermined axial shimiro. The side lip 31a is formed in a bifurcated shape on the inner diameter side, and has a dust lip 31b and a grease lip 31c when slidably contacting the outer peripheral surface of the cylindrical portion 30a of the slinger 30 via a predetermined radial shimiro.

  Here, the side lip 31a is not straight, and the inner peripheral surface 33 is formed in a concave shape having a predetermined radius of curvature R3. Thereby, it is possible to prevent the side lip 31a from becoming solid and to increase the contact surface pressure of the lip portion, thereby improving the sealing performance. The radius of curvature R3 of the inner peripheral surface 33 is set in a range of 1.0 to 3.0 times the lip length W3, like the outer side lip 25a described above. The grease 28 is applied to the inner peripheral surface 33 of the side lip 31a.

  FIG. 9 schematically shows a contact state between the slinger 30 and the side lip 31a. As can be seen from this, even when the contact between the side lip 31a and the standing plate portion 30b of the slinger 30 is weak, the contact state of the tip portion 34 of the side lip 31a is less likely to be unstable, per edge, and the contact pressure increases. This improves the sealing performance.

  On the other hand, as shown in FIG. 10, when the contact between the side lip 31 a and the standing plate portion 30 b of the slinger 30 becomes strong, the inner peripheral surface 33 of the side lip 31 a is formed in a concave shape. It is possible to prevent the concave surface of the inner peripheral surface 32 from remaining and not becoming solid, and the sliding contact width L1 to be substantially shortened. As a result, it is possible to prevent the contact area from increasing and the contact surface pressure from decreasing.

  As described above, the inner peripheral surface 33 of the side lip 31a is formed in a concave shape, and the configuration of the above-described embodiment is combined, that is, the standing plate portion 30b of the slinger 30 is radially outward. By gradually inclining toward the outer side, the sliding contact surface of the side lip 31a can be reliably prevented from becoming a solid contact and the contact surface pressure of the lip can be increased to further improve the sealing performance. it can.

  The embodiment of the present invention has been described above, but the present invention is not limited to such an embodiment, and is merely an example, and various modifications can be made without departing from the scope of the present invention. Of course, the scope of the present invention is indicated by the description of the scope of claims, and further, the equivalent meanings described in the scope of claims and all modifications within the scope of the scope of the present invention are included. Including.

  The wheel bearing device according to the present invention can be applied to first to third generation wheel bearing devices of the inner ring rotation type.

1, 2 1 Inner member 2, 22 Hub wheel 2a, 3a Inner rolling surface 2b Small diameter step 2c Serration 3 Inner ring 4 Wheel mounting flange 4a, 4b Side surface on the inner side of the wheel mounting flange 5 Hub bolt 6 Rolling element 7 Cage 8 , 23 Outer seal 9, 24 Inner seal 10 Outer member 10a Outer rolling surface 10b Car body mounting flange 11 Inner side base 12, 16 of the wheel mounting flange Core 12a, 16a Fittings 12b, 16b Portions 13, 17, 25, 31 Seal members 13a, 17a, 25a, 31a Side lips 13b, 17b, 25b, 31b Dustrips 13c, 17c, 25c, 31c Grease lips 14, 29 Seal plates 15, 30 Slinger 15a, 30a Cylindrical 15b, 30b Standing plate 17aa Side lip tip surface 18 Labyrinth 19, 32 Outer side surfaces 20, 26, 33 of the slinger standing plate portion Inner peripheral surface 27 of the side lip 28 Inner peripheral surface 28 of the dust lip 34 Grease 34 applied to the lip 51 End portion 51 of the side lip Sealing device 52 Metal core 53 Seal member 54 Slinger 55 Standing plate portion 55a Axial end surface portion 56 Side lip 56a Tip end surface 56b Inner peripheral surface 57 Cylindrical portion 57a Outer peripheral surface 58 of cylindrical portion Dustrip L, L1 Sliding contact widths R1, R3 of side lip Side lip radius of curvature R2 Dustrip inner radius of curvature W1, W3 Side lip length W2 Dustrip length θ Tilt angle θ1 of the mating member with which the side lip slides Side lip sliding Head apex angle

Claims (8)

An outer member in which a double row outer rolling surface is integrally formed on the inner periphery;
From a hub wheel integrally having a wheel mounting flange for mounting a wheel at one end and having a small-diameter step portion extending in the axial direction on the outer periphery, and at least one inner ring press-fitted into the small-diameter step portion of the hub ring An inner member in which a double row inner rolling surface facing the outer rolling surface of the double row is formed on the outer periphery,
A double row rolling element housed movably between the rolling surfaces of the inner member and the outer member;
In a wheel bearing device comprising: a seal that seals both side openings of an annular space formed between the outer member and the inner member;
At least one of the seals extends inward in the radial direction from a cylindrical fitting portion that is press-fitted into the inner periphery of the end portion of the outer member via a predetermined shimiro, and the end portion of the fitting portion. It comprises an inner diameter portion, a cored bar formed by pressing from a steel plate, and a seal member made of synthetic rubber integrally joined to the cored bar by vulcanization adhesion,
The seal member has a side lip that extends in a radially outward direction, the side lip is slidably contacted with the mating member via an axial shimiro, and the slidable contact surface of the mating member is radially outward. The wheel bearing device is characterized by being inclined toward the side lip side by 86.5 ° or more and less than 90 °.   The wheel bearing device according to claim 1, wherein an inner peripheral surface of the side lip is formed in a concave shape having a predetermined radius of curvature.   The wheel bearing device according to claim 2, wherein a radius of curvature of an inner peripheral surface of the side lip is set in a range of 1.0 to 3.0 times a length of the side lip.   The seal on the outer side of the seal is composed of an integral seal composed of the core metal and the seal member, and the seal member is a side lip that slidably contacts the side surface on the inner side of the wheel mounting flange, and has a circular cross section. The inner side base of the wheel mounting flange formed in an arc shape is formed to be inclined to the inner side of the inner side of the wheel mounting flange, and is formed to be inclined to the inner side of the dust strip and the bearing in sliding contact with a predetermined axial direction. 4. A grease lip that is slidably contacted with a direction squeeze is integrally formed, and the side surface on the inner side of the wheel mounting flange is formed so as to be gradually inclined toward the inner side in the radially outward direction. Wheel bearing device.   The inner peripheral surface of the dust lip is formed in a concave shape having a predetermined radius of curvature, and the radius of curvature is set in a range of 1.0 to 3.0 times the length of the dust lip. The wheel bearing apparatus described in 1.   The seal is composed of a pack seal made of an annular seal plate and a slinger that are formed in a substantially L-shaped cross section and arranged to face each other, and the seal plate is made of the core metal and a seal member, and the slinger Has a cylindrical portion press-fitted into the outer periphery of the inner ring, a standing plate portion extending radially outward from the cylindrical portion, and the seal member is in sliding contact with the standing plate portion of the slinger, and the cylinder A radial lip that is in sliding contact with a portion via a predetermined radial shimoshiro is provided, and a side surface of the slinger is formed so as to be gradually inclined radially outward from an end portion of the cylindrical portion. A wheel bearing device according to claim 1.   The wheel bearing device according to claim 1, wherein grease is applied to a sliding contact portion of the seal lip.   The tip end portion of the fitting portion of the cored bar is formed thin, and the seal member wraps around and joins the tip end portion to form a half metal structure. The wheel bearing apparatus described in 1.

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