JP2014126106A - Rolling bearing unit for supporting wheel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rolling bearing unit for supporting a wheel capable of more effectively preventing intrusion of foreign matters into an internal space and having high durability, without increasing rotational resistance.SOLUTION: A labyrinth lip 33 is positioned at a radial outer part with respect to a step portion 20 between a forging plane formed just molding a rotation-side flange 12 by side extrusion of cold-forging (having streaks in radial direction), and a ground sliding plane 21, on which grinding work is performed, at a radial outer part with respect to a seal lip 32a disposed near the outermost space. By making a tip portion of the labyrinth lip 33 and the step portion 20 be close and opposed to each other over the whole periphery in a state of being superposed in the radial direction, the labyrinth seal in the axial direction is formed between an inner peripheral face of the tip portion of the labyrinth lip 33 and an outer peripheral face of the step portion 20.

Description

  The present invention relates to, for example, a rolling bearing unit for rotatably supporting a wheel of an automobile with respect to a suspension device. The wheel support is formed by closing an end opening of an inner space of a bearing with a seal ring or a combination seal ring. The present invention relates to a rolling bearing unit for use.

  As a rolling bearing unit for rotatably supporting a wheel of an automobile with respect to a suspension device, for example, in Patent Document 1, one end opening of an internal space in which a rolling element is installed is a seal ring, and the other is a combined seal ring. Describes the structure of a wheel bearing rolling bearing unit sealed by In order to ensure the durability of such a wheel-supporting rolling bearing unit, the sealing performance of these sealing devices is improved to prevent entry of foreign matter into the internal space and leakage of grease filled in the internal space. It is important to prevent enough. On the other hand, these sealing devices are used under severe conditions where muddy water or the like is applied during use. In particular, in the seal ring, foreign matter such as muddy water guided radially inward along the inner surface of the flange slides between the tip edge of the seal lip constituting the seal ring and the inner surface of the flange. There is a possibility of entering into the part and causing damage such as abnormal wear to the sliding part. Further, if the water of the muddy water that has entered the seal space evaporates and solidifies, and solid content (mud) accumulated in the seal space adheres to the seal lip, the movement of the seal lip may be hindered. As a result, a part of the front end edge of the seal lip is lifted from the seal sliding surface, and foreign matters such as muddy water may enter the seal space through the part.

  As a structure for improving the sealing performance of the combined seal ring, Patent Document 2 discloses that the tip end edge of the second seal lip constituting the second seal ring fitted on the outer ring is connected to the rotation-side annular portion of the slinger. Among them, a structure is described in which the entire surface is slid on the side surface opposite to the seal ring. According to such a structure, foreign matter can be prevented from entering the seal internal space, but the number of parts increases and the cost increases. Further, an installation space for the portion where the second seal ring is provided is required, and there is a possibility that the degree of freedom in design may be limited to prevent interference with other articles provided adjacent to the rolling bearing unit. Further, since the second seal lip is provided in a state of being added to the seal lip originally provided on the combined seal ring side, the sliding portion is increased and the rotational resistance (dynamic torque) of the rolling bearing unit is increased. There was a problem.

JP 2007-085478 A JP 2008-151111 A

  In view of the circumstances as described above, the present invention improves the sealing performance of the sealing device that closes the end opening of the internal space existing between the stationary and rotating bearing rings constituting the rolling bearing unit, The invention has been invented to realize a rolling bearing unit for supporting a wheel, which has a further excellent effect of preventing foreign matter from entering the internal space in which the rolling elements are installed, and has excellent durability without increasing the rotational resistance.

A rolling bearing unit for supporting a wheel according to the present invention has an outer ring having an outer ring raceway on an inner peripheral surface, an inner ring raceway in a portion of the outer peripheral surface facing the outer ring raceway, and is arranged concentrically with the outer ring. An inner ring, a plurality of rolling elements provided between the outer ring raceway and the inner ring raceway so as to be freely rollable, and radially extending radially outward from an outer peripheral surface of the inner ring, and the inner ring is formed by cold forging. A flange integrally formed with the outer ring, and a seal ring that closes an end opening of the inner space existing between the inner peripheral surface of the outer ring and the outer peripheral surface of the inner ring, and grinding the outer peripheral surface of the inner ring Provided with a processed sliding surface, the seal ring comprises a cored bar fixed to the end of the outer ring, and an elastic sealing material reinforced by the cored bar. And at least one sheet sliding on the entire sliding surface. A labyrinth seal is formed between the lip and the side surface of the flange. The lip is provided further radially outward than the seal lip, and its tip is opposed to the side surface of the flange in close proximity to the entire circumference. It is equipped with a labyrinth slip.
In particular, in the rolling bearing unit for supporting a wheel of the present invention, a step portion is formed between the forging surface of the cold forging and the sliding surface on the side surface of the flange near the proximal end, The leading end of the labyrin slip is positioned radially outward from the stepped portion, and the leading end of the labyrin slip and the stepped portion are overlapped in the radial direction.

According to the wheel support rolling bearing unit of the present invention configured as described above, the sealing performance by the sealing device is improved, the effect of preventing foreign matter from entering the internal space in which the rolling elements are installed is further improved, and is excellent. A wheel bearing rolling bearing unit with high durability can be realized without increasing the rotational resistance.
In particular, in the case of the present invention, the labyrinth slip is extended further to the flange side than the sliding point of the seal lip, and the tip of the labyrinth slip is made to face the step portion on the side surface of the relatively rotating flange. Therefore, the labyrinth effect by the labyrinth slip can be improved. In addition, the flange side surface of the outer diameter side portion from the stepped portion is a forged surface, and radial streaks are formed by cold forging. Increases the effect of swinging outward.

  As a result, the amount of foreign matter such as muddy water reaching the seal lip is reduced, damage to the sliding part of the seal lip such as abnormal wear occurs, and a large amount of solid matter adheres to the movement of the seal lip. Can be prevented. Accordingly, it is possible to ensure good durability over a long period of time and to ensure the durability of the wheel bearing rolling bearing unit. Moreover, the rotational resistance of the wheel bearing rolling bearing unit does not increase with the provision of the labyrinth slip that is a non-contact lip.

Sectional drawing of the rolling bearing unit for wheel support which shows 1st Embodiment. Same as above, side view (a) for explaining the inner ring main body, sectional view (b) along the line AA, side view (c) for explaining the outer ring, along the line BB Sectional drawing (d). The fragmentary sectional view of a seal ring. The fragmentary sectional view which shows the modification of a seal ring similarly. Sectional drawing of the rolling bearing unit for wheel support which shows 2nd Embodiment. The fragmentary sectional view of a seal ring. The fragmentary sectional view of a combination seal ring. Sectional drawing of the rolling bearing unit for wheel support which shows 3rd Embodiment. The fragmentary sectional view of a seal ring. The fragmentary sectional view of a combination seal ring.

[First Embodiment]
1 to 3 show a first embodiment of the present invention. The wheel support rolling bearing unit 1 of this embodiment is a bearing unit for a driven wheel of an inner ring rotation type, and an inner ring 3 that is a rotation side raceway is provided on the inner diameter side of an outer ring 2 that is a stationary side raceway. It is rotatably supported via balls 4 and 4 which are rolling elements. The outer ring 2 is provided with a stationary side flange 5 for supporting and fixing to a suspension device (not shown) on the outer peripheral surface, and double row outer ring raceways 6 and 6 on the inner peripheral surface. The inner ring 3 is an inner ring body 7 and an inner ring element 8 which are combined and fixed by a caulking portion 9, and has double-row inner ring raceways 10, 10 on the outer peripheral surface. The balls 4 and 4 are held by the cages 11 and 11 between the inner ring raceways 10 and 10 and the outer ring raceways 6 and 6, respectively. It is provided to roll freely.

A rotation-side flange 12 is provided at a portion of the inner ring main body 7 that is close to the outer end in the axial direction and protrudes from the opening at the outer end in the axial direction of the outer ring 2. A base end portion of a plurality of studs 13 is supported and fixed to the rotation side flange 12, and a wheel constituting a wheel and a disk rotor constituting a braking device are attached to the rotation side flange 12 by each stud 13. Supports and can be fixed. The outside in the axial direction means the outside in the width direction of the vehicle in the assembled state to the vehicle, and is the left side of each drawing excluding FIGS. 2 (a) and 2 (c). On the other hand, the right side of each figure (excluding FIGS. 2A and 2C), which is the inner side in the width direction of the vehicle, is referred to as the inner side in the axial direction.
In the illustrated example, the balls 4 are used as rolling elements. However, in the case of a wheel bearing rolling bearing unit used for a heavy vehicle, a tapered roller may be used as the rolling element.

  A seal ring 14 is mounted between the inner peripheral surface of the outer end in the axial direction of the outer ring 2 and the outer peripheral surface of the intermediate portion in the axial direction of the inner ring 3, and the inner peripheral surface of the outer ring 2 and the outer peripheral surface of the inner ring 3 And closes the axially outer end opening of the internal space 15 provided with the plurality of balls 4 and 4. Further, by closing the axially inner end opening of the outer ring 2 with the cover 16, foreign matter such as dust and rainwater can be prevented from entering from the outer space into the inner space 15, and the grease filled in the inner space 15 can be removed from the outside. It is intended to prevent leakage into the space.

As shown in FIGS. 2 (a) and 2 (b), the inner ring body 7 has a radially outer portion (left side of FIG. 2 (b)) on the outer circumferential surface and a direction perpendicular to the rotation center axis radially outward. The rotation side flange 12 extending radially is formed, and a plurality of mounting holes 24 are formed in the rotation side flange 12 at substantially equal intervals in the circumferential direction in order to fix the stud 13. The rotation side flange 12 is configured not to be connected in the circumferential direction at the pitch circle position of the mounting holes 24. Further, a pilot portion 23 used for positioning the wheel is projected from the outer side of the rotation side flange 12 in the axial direction.
In such an inner ring body 7, the rotating side flange 12 extending radially in a direction perpendicular to the rotation center axis is formed integrally with the inner ring body 7 by cold side extrusion (cold forging). . In addition, the pilot portion 23 constituted by the unpressed portion at the time of cold side extrusion is also formed integrally with the inner ring body 7.

  A small-diameter step portion 25 is formed on the inner side of the inner ring main body 7 (on the right side in FIG. 2B), and the inner ring element 8 is fitted and fixed to the small-diameter step portion 25. The inner ring raceway 10 is formed on the outer peripheral surface of the inner ring element 8, and the outer ring inner raceway surface 10 is formed on the outer peripheral surface of the axially intermediate portion of the inner ring main body 7. The inner end portion in the axial direction of the inner ring main body 7 is formed in a cylindrical shape, and the inner ring element 8 is crimped to the inner ring main body 7 by spreading the cylindrical portion (the caulking portion 9) outward in the radial direction. Fixed. In addition, the inner ring element 8 can also be configured to be fastened and fixed by a nut (not shown) on the inner side in the axial direction of the inner ring main body in addition to caulking and fixing.

On the other hand, as shown in FIGS. 2 (c) and 2 (d), the outer ring 2 is entirely formed in a hollow cylindrical shape, and is formed on the outer peripheral surface of the inner ring 3 on the inner peripheral surface of the outer ring 2. Double row outer ring raceways 6, 6 corresponding to the inner ring raceways 10, 10 are formed. The stationary flange 5 is formed on the outer peripheral surface of the axially intermediate portion of the outer ring 2 so as to extend radially outward in a direction perpendicular to the rotation center axis. A plurality of mounting holes 24a for attaching the outer ring 2 to the suspension device are formed in the stationary side flange 5, and the stationary side flange 5 is configured not to be connected in the circumferential direction at the pitch circle positions of these mounting holes 24a. Further, on the inner side in the axial direction of the stationary flange 5 (on the right side in FIG. 2D), the outer ring 2 is positioned in the radial direction on the inner diameter surface of the knuckle (not shown) constituting the suspension device, and the cover 16 A cylindrical portion is formed to fix the inner part.
In such an outer ring 2, stationary side flanges 5 that extend radially in a direction orthogonal to the rotation center axis are integrally formed with the outer ring 2 by cold side extrusion (cold forging).

  The wheel support rolling bearing unit 1 is provided with a rotation detection device for detecting the rotation state of the inner ring 3 (the wheel supported and fixed to the inner ring 3). This rotation detection device includes an encoder 17 fixed concentrically with the inner ring 3 on the outer peripheral surface of the inner end of the inner ring element 8 constituting the inner ring 3 in the axial direction, and is attached to the cover 16 and close to the encoder 17. It is comprised with the sensor 18 arrange | positioned facing. The encoder 17 is a ring-shaped permanent magnet magnetized in the axial direction, and the detected surface thereof has N poles and S poles alternately arranged at equal intervals in the circumferential direction. By detecting a change in the magnetic flux density accompanying the rotation of the encoder 17 with the sensor 18, the rotational speed of the inner ring 3 (wheel) can be detected.

As shown in FIG. 3, the seal ring 14 incorporated to seal the axially outer end opening of the internal space 15 is composed of a core metal 30 and a seal material 31. The metal core 30 is formed by forming a metal plate such as a mild steel plate into a substantially annular shape, and an outer diameter side edge of the metal core 30 is formed on an inner peripheral surface of an outer end portion in the axial direction of the outer ring 2. The groove 22 is internally fitted and fixed with a part of the sealing material 31 interposed.
The sealing material 31 is made of an elastic material such as an elastomer such as rubber, and is bonded and fixed to the core metal 30. Two contact-type seal lips 32a and 32b and a labyrinth seal form a labyrinth seal. And a lip 33. The seal lips 32a and 32b have their respective leading edges slid over the entire circumference on a sliding surface 21 provided on the outer peripheral surface of the intermediate portion in the axial direction of the inner ring 3. This sliding surface 21 is integrally ground together with the inner ring raceway 10 after heat treatment, and is made a smooth surface having no radial or axial streak, thereby ensuring the sealing performance by the seal lips 32a and 32b. doing.

The labyrinth slip 33 is provided radially outward from the seal lip 32a provided closest to the outer space, and the position of the labyrin slip 33 is provided on the inner side surface of the base end portion of the rotation side flange 12. Regulated in relation to the part 20. In addition, the stepped portion 20 is subjected to a grinding process in which the sealing lips 32a and 32b slide on the forged surface (having a streak in the radial direction) formed by the side extrusion of the cold side forging of the rotary flange 12 and the sealing lips 32a and 32b. It is provided between the applied sliding surface 21, and is a boundary portion between the forged surface and the sliding surface 21.
The labyrinth slip 33 is positioned radially outward from the stepped portion 20, and the leading end portion of the labyrinth slip 33 and the stepped portion 20 are overlapped in the radial direction (the leading edge of the labyrinth slip 33 is a stepped portion). 20 is located outside the axial direction). And the front-end | tip inner peripheral surface of the labyrinth slip 33 and the outer peripheral surface of the step part 20 are made to oppose and approach over the perimeter. Thus, an axial labyrinth seal is formed between the inner peripheral surface of the tip of the labyrinth slip 33 and the outer peripheral surface of the stepped portion 20. Further, the labyrinth slip 33 is inclined in a direction toward the radially outer side toward the outer side in the axial direction (front end side).

In the case of the wheel support rolling bearing unit 1 of the present embodiment having the above-described configuration, the effect of preventing foreign matter from entering the inner diameter side of the labyrinth slip 33 is improved. Even when it enters and adheres to the inner side surface of the rotation side flange 12, a structure in which this foreign matter can be easily discharged is realized.
In other words, since the labyrinth slip 33 is inclined in the direction toward the radially outer side as it goes toward the tip side, the muddy water or the like that reaches the outer circumferential surface of the labyrin slip 33 along the outer circumferential surface of the outer ring 2 is transferred to the labyrin slip 33. By guiding it to the base end and flowing it to the bottom, foreign matter can be prevented from entering through the labyrinth seal. Further, even when foreign matter such as moisture enters the inner diameter side of the labyrinth slip 33, the foreign matter blown outward in the radial direction by the centrifugal force of the rotary flange 12 increases in the inner diameter dimension toward the tip edge. Along the inner peripheral surface of the inclined labyrinth slip 33, it is effectively discharged toward the external space.

  Furthermore, since the surface of the flange has radial streaks due to friction with the forging die, the sliding surface 21 of the seal lip is subjected to grinding or the like. In comparison, since the material does not flow easily, a large corner R is formed on the inner side in the axial direction of the proximal end portion of the flange. Therefore, since a large space exists between the side surface of the rotation side flange 12 in the portion that seals the axial direction outer end opening of the internal space 15, there is a severe environment in which muddy water or the like easily enters. The bowl-shaped labyrinth slip 33 that constitutes the seal ring 14 of the present embodiment is provided so as to cover the entire sliding surface 21 that has been subjected to the grinding process, and its front end portion is close to the step portion 20 and is opposed thereto. This prevents foreign matters such as muddy water from entering the sliding surface 21. Further, since the sliding surface 21 on the inner diameter side of the labyrinth slip 33 is a ground grinding surface, the generation of rotating airflow due to the streak is prevented. On the other hand, radial streaks (forged surfaces) are present on the outer diameter side portion of the step portion 20 of the rotation side flange 12, and the muddy water that has entered the sliding surface 21 is removed by the centrifugal force of the rotation flange 12. The effect of shaking off to the side is enhanced to promote drainage. In addition, the forged surface where the bondage treatment (lubricating film treatment) remains during the cold forging process has corrosion resistance, and the rust prevention property is excellent by making the tip of the labyrin slip 33 face the cold forged surface. It has a configuration.

  Further, the outer ring 2 and the inner ring main body 7 formed by cold forging have excellent finished dimensional accuracy after forming and a good surface can be obtained, so that the cost can be reduced by omitting the machining in the subsequent process. I can do things. Furthermore, since the strength of the stationary side flange 5 and the rotary side flange 12 formed by side extrusion in the cold increases due to work hardening, the outer ring 2 and the inner ring main body 7 are reduced in weight while ensuring sufficient strength. I can do things.

  FIG. 4 shows a modification of the first embodiment. The metal core 30a constituting the seal ring 14a in the present modification is formed by forming a metal plate such as a mild steel plate into a substantially L-shaped cross section, and a fitting cylinder part 34 and an outer edge in the axial direction of the fitting cylinder part 34 And an annular portion 35 that is bent radially inward. The fitting tube portion 34 is fitted and fixed to the inner peripheral surface of the outer end portion of the outer ring 2 in the axial direction by an interference fit. This configuration eliminates the need for processing for forming the annular groove 22 on the inner peripheral surface of the outer ring 2.

[Second Embodiment]
5 and 6 show a second embodiment of the present invention. A wheel support rolling bearing unit 1a according to the present embodiment is a bearing unit for an outer ring rotating type driven wheel, and includes an outer ring 2a that is a rotating side bearing ring having double-row outer ring raceways 6a and 6b on an inner circumferential surface, and an outer circumference. The inner ring 3a, which is a stationary-side bearing ring having double-row inner ring raceways 10a, 10b on the surface, and a plurality of rollers can be rolled in each row between the outer ring raceways 6a, 6b and the inner ring raceways 10a, 10b. Balls 4a and 4b, which are rolling elements to be disposed, are provided.

The outer ring 2a has a rotation-side flange 12a extending radially outwardly on the outer side in the axial direction (left side in FIG. 5). A plurality of studs 13 for mounting a wheel (not shown) constituting a wheel (not shown) and a disk rotor constituting a braking device are implanted on the rotation side flange 12a at substantially equal intervals in the circumferential direction. .
The inner ring 3a has an inner ring main body 7a in which the (inner) inner ring raceway 10b is formed on the outer peripheral surface of the axially intermediate portion, and the inner end of the inner ring main body 7a in the axial direction (on the right side in FIG. 5). A stationary flange 5a extending outward in the radial direction is formed at the end). A small-diameter step portion 25 is formed at the axially outer end portion of the outer peripheral surface of the inner ring main body 7a, and the inner ring in which the (outer) inner ring raceway 10a is formed on the outer peripheral surface. Element 8 is fitted externally. The inner ring element 8 is fixed to the inner ring main body 7a by caulking the axially outer end portion (caulking portion 9) of the inner ring main body 7a.

In the present embodiment, the outer ring raceway 6b inside the outer ring 2a is formed with a larger diameter than the outer ring raceway 6a outside, and the inner ring raceway 10b inside the inner ring 3a is formed with a larger diameter than the outer ring raceway 10a, The pitch circle diameter (PCD) of the ball rows of the inner balls 4b is made larger than the pitch circle diameter of the ball rows of the outer balls 4a. And each ball | bowl 4a, 4b arrange | positioned in these double rows is provided with the contact angle of the back combination type with the preload. Further, the number of balls 4b constituting the inner ball row is made larger than the number of balls 4a constituting the outer ball row.
In the present embodiment, the balls 4a and 4b have the same diameter, but the outer diameter of the inner ball 4b can be made smaller than the outer diameter of the outer ball 4a.

The outer ring 2a is made of an annular billet made of carbon steel for mechanical structure that has been spheroidized and annealed, and the outer peripheral surface and the inner peripheral surface are formed by cold forging, and the rotating side flange is formed by lateral extrusion. 12a is molded. The rotation-side flange 12a has a so-called star flange shape in which a plurality of flange pieces are arranged in the circumferential direction of the outer ring 2a (see FIG. 2A). Further, since the outer side surface in the axial direction of the rotation side flange 12a and the outer peripheral surface of the pilot portion 23 are surfaces having good dimensional accuracy, it is not necessary to perform machining after cold forging.
The inner ring main body 7a constituting the inner ring 3a is made of a cylindrical billet made of carbon steel for mechanical structure that has been spheroidized and annealed, formed by cold forging, and formed a stationary flange 5a by side extrusion. doing. By the work hardening of the side extrusion molding, the hardness of the root portion of the stationary flange 5a can be increased, and the strength can be improved. On the other hand, the axially outer end portion of the inner ring main body 7a that does not undergo significant deformation during cold forging remains as hard as a billet, and therefore, the caulking process for fixing the inner ring element 8 can be easily performed.

  As described above, according to the wheel bearing rolling bearing unit 1a of the present embodiment, the pitch circle diameter (PCD) of the ball train of the inner ball 4b is larger than the pitch circle diameter of the ball train of the outer ball 4a. Therefore, the load capacity of the inner ball train (ball 4b) can be increased while suppressing an increase in the weight of the bearing unit, so that the durability of the rolling bearing unit can be improved. In addition, since a separate member for fixing the inner ring element 8 to the inner ring main body 7a is not necessary, the bearing structure can be simplified, and the rolling bearing unit can be reduced in weight and cost.

  In the present embodiment, the axially inner end opening of the internal space 15 existing between the inner peripheral surface of the outer ring 2a and the outer peripheral surface of the inner ring 3a is sealed with a seal ring 14b as shown in FIG. doing. This seal ring 14b has substantially the same configuration as the seal ring 14a shown in FIG. 4 described above, and the tip of the labyrin slip 33a is ground and forged on the outer surface in the axial direction of the stationary flange 5a. It is made to face in close proximity to the stepped portion 20 that becomes the boundary with the sliding surface 21. Further, since the seal ring 14b is fixed to the outer ring 2a, which is a rotating raceway, the distal end portion of the labyrinth slip 33a is deformed radially outward when a centrifugal force is applied during the rotation of the outer ring 2a. Therefore, considering the influence of the centrifugal force, the distance between the inner peripheral surface of the tip of the labyrin slip 33a and the outer peripheral surface of the stepped portion 20 is smaller than the labyrin slip 33 shown in FIGS. doing.

  In addition, when the outer ring 2a is in a stationary state (when the automobile is stopped), the tip of the labyrinth slip 33a may be lightly contacted (contacted with zero tightening) to the stepped portion 20. As a result, when the automobile is stopped, the labyrinth slip 33a seals the sliding surface 21 to prevent intrusion of foreign matter, and when the automobile is running, the labyrinth slip 33a is separated from the stepped portion 20 by centrifugal force. Since it forms a labyrinth seal in a non-contact state, the rotational torque of the rolling bearing unit does not increase.

  FIG. 7 shows a modification of the second embodiment. The combination seal ring 19 of this modification is a sealing device that seals the axially inner end opening of the internal space 15, and is configured by combining a slinger 40 and a seal ring 41. The slinger 40 is formed by bending a metal plate to form a generally annular shape with a substantially U-shaped cross section. The slinger 40 is radially outward from the slinger cylinder 42 and the axial inner edge of the slinger cylinder 42. The slinger ring part 43 is bent at the center, and the flange part 44 is bent from the radial outer end edge of the slinger ring part 43 to the outside in the axial direction. Such a slinger 40 is fixed to the inner ring 3a by fitting the slinger cylindrical portion 42 to the inner side in the axial direction of the inner ring 3a by an interference fit. Further, in this state, the flange portion 44 is positioned radially outward from the outer peripheral edge of the axially inner end of the outer ring 2a, and the inner peripheral surface of the tip portion of the flange portion 44 is opposed to the outer peripheral surface of the outer ring 2a. I am letting.

  The seal ring 41 includes a metal plate core 45 and an elastic member 46. The elastic member 46 is bonded and fixed to the cored bar 45, and includes a plurality (three in the illustrated example) of seal lips 47a, 47b, 47c and a bowl-shaped labyrinth slip 51 constituting a labyrinth seal. I have. The metal core 45 is formed by bending a metal plate and is formed into an annular shape with a cross-sectional crank shape. The seal cylinder 48 and a radial direction from the axial outer end edge of the seal cylinder 48 are provided. The seal ring portion 49 is bent inward, and the fitting ring portion 50 is bent radially outward from the axial inner end edge of the seal cylindrical portion 48. The seal ring 41 having such a cored bar 45 has a seal cylindrical portion 48 fitted into the inner end portion of the outer ring 2a in the axial direction by an interference fit, and the outer circumferential surface of the fitting ring portion 50 is disposed on the axially outer surface. The outer ring 2a is fixed to the outer ring 2a by abutting against the inner end surface in the axial direction. In this state, the tip edge of the seal lip 47a is slid over the entire circumference, and the tip edge of each seal lip 47b, 47c is on the outer periphery of the slinger cylindrical portion 42. Touching.

  On the other hand, the labyrinth slip 51 is provided further outward in the radial direction than the seal lip 47a provided at the outermost radial direction, and overlaps the outer peripheral edge of the inner end in the axial direction of the outer ring 2a in the axial direction. Formed in position. And the front-end | tip part of this labyrinth slip 51 and the axial direction outer side surface of the said slinger ring part 43 are made to oppose and adjoin over the perimeter. Thereby, a labyrinth seal in the radial direction of the labyrinth gap a is formed between the leading edge of the labyrinth slip 51 and the axially outer side surface of the slinger ring portion 43. Further, the labyrinth seal in the axial direction of the labyrinth gap b is provided between the outer peripheral surface of the labyrin slip 51 and the inner peripheral surface of the flange portion 44 in a state where the radial labyrinth seal is bent outward in the axial direction. Forming. The labyrinth gap a of the radial labyrinth seal is smaller (a <b) than the labyrinth gap b of the axial labyrinth seal.

  Also in the present embodiment, the labyrinth slip 51 is inclined in the direction toward the radially outer side toward the inner side in the axial direction (front end side), and the flange portion 44 is formed on the outer side in the axial direction (front end). It is made to incline in the direction which goes to a radial direction outer side as it goes to the side. Thereby, the muddy water or the like that has entered the inner diameter side of the labyrin slip 51 is guided radially outward along the inclined inner peripheral surface of the labyrin slip 51 by the centrifugal force of the rotating seal ring 41, and the inclined flange portion 44 can be discharged to the external space along the inner peripheral surface. Accordingly, it is possible to effectively prevent foreign matters such as muddy water from entering the seal internal space existing on the bearing inner side with respect to the seal lip 47a. Further, it is possible to prevent foreign matters from adhering to the outer peripheral surface of the seal lip 47a present in the portion closest to the outer space, and the behavior of the seal lip 47a is impaired, resulting in a decrease in sealing performance.

As described above, the sealing lip 47a extending in the axial direction is newly provided with respect to the configuration of the seal ring 14b shown in FIG. 6 by fitting and fixing the slinger 40 to the inner ring 3a as a sliding ring. It is possible to further improve the sealing performance. The labyrinth slip 51 may be configured to be lightly contacted with the slinger ring portion 43 (contact with zero tightening allowance).
Since the configuration and operation of the other parts are the same as those in the first embodiment described above, the same parts are denoted by the same reference numerals, and redundant description is omitted.

[Third Embodiment]
8 to 10 show a third embodiment of the present invention. The wheel-supporting rolling bearing unit 1b of the present embodiment is an inner ring rotating type drive wheel bearing unit, and has a spline hole 26 at the center of the inner ring 3b (the inner ring main body 7b constituting the inner ring 3b) that is a rotating side race. The spline shaft 28, which is a drive shaft fixed to the outer end surface in the axial direction of the constant velocity joint outer ring 27, can be engaged. Further, the inner side surface of the nut 29 is abutted against the peripheral portion of the outer peripheral edge of the spline hole 26 in the inner peripheral surface of the inner ring 3b. At the time of assembling to the vehicle, the spline shaft 28 is engaged with the spline hole 26, and a nut 29 is screwed into a male screw portion provided at the front end portion of the spline shaft 28, and further tightened to be the front end portion of the spline shaft 28. The inner ring 3b and the constant velocity joint outer ring 27 are coupled and fixed to each other.

The inner ring body 7b constituting the inner ring 3b includes an inner ring element 10 having an (outer) inner ring raceway 10c at an axially intermediate portion and an inner ring element 8 having an (inner) inner ring raceway 10d at an outer peripheral surface at an axially inner end portion. It is fitted. The inner ring body 7b is plastically deformed radially outward to form a crimped portion 9 to restrain the inner ring element 8, and the inner ring element 8 is coupled and fixed to the inner ring body 7b. Yes. Further, the outer inner ring raceway 10c has a diameter larger than the inner inner ring raceway 10d.
The outer ring 2b has double-row outer ring raceways 6c, 6d formed on the inner peripheral surface, and the outer outer ring raceway 6c has a larger diameter than the inner outer ring raceway 6d. A ball 4c is provided between the outer outer ring raceway 6c and the outer inner ring raceway 10c, and a plurality of balls 4d are provided between the inner outer ring raceway 6d and the inner ring raceway 10d so as to be capable of rolling. Yes. Each of the balls 4c and 4d arranged in the double row is preloaded by the contact angle of the back combination type, and the pitch circle diameter of the ball row of the outer ball 4c is set to be equal to that of the ball row of the inner ball 4d. It is larger than the pitch circle diameter. With this configuration, the moment rigidity can be improved while preventing an increase in the size of the rolling bearing unit, so that stability during turning of the automobile is ensured.

  In the present embodiment, the inner space 15 is sealed with an axial outer end opening by a seal ring 14c and an axial inner end opening by a combination seal ring 19a. As shown in FIG. 9, the seal ring 14c includes a cored bar 30b and a sealing material 31b. The metal core 30b is formed by bending a metal plate such as a mild steel plate, and includes a fitting cylinder portion 34 and an annular ring bent radially outward from the axial outer end edge of the fitting cylinder portion 34. A portion 35a, a bent portion 36 folded in a U-shape from the inner end edge in the axial direction of the fitting tube portion 34 toward the radially inward and axially outer sides, and the axial direction from the outer peripheral edge of the annular portion 35a. And a cylindrical portion 37 bent inward. Then, the fitting cylinder portion 34 is fitted and fixed to the inner peripheral surface of the outer end portion in the axial direction of the outer ring 2b by an interference fit, and the inner side surface in the axial direction of the annular portion 35a is fixed to the outer end surface in the axial direction of the outer ring 2b. In this state, a part of the sealing material 31b is abutted.

The sealing material 31b is made of an elastic material such as an elastomer such as rubber, and is fixedly bonded to the core metal 30b. The sealing material 31b forms a labyrinth seal with two contact-type seal lips 32a and 32b. Labyrinth slip 33 is provided. The leading edges of the seal lips 32a and 32b are slid over the entire circumference on a sliding surface 21 that is ground on the outer circumferential surface of the inner ring 3b.
The labyrinth slip 33 is positioned more radially outward than the seal lip 32a provided closest to the outer space, and more radially outward than the step portion 20 provided on the inner surface of the proximal end portion of the rotation side flange 12. In addition, the tip of the labyrinth slip 33 and the stepped portion 20 are overlapped in the radial direction. And the front-end | tip part internal peripheral surface of the labyrinth slip 33 and the outer peripheral surface of the step part 20 are made to oppose and adjoin over the perimeter, and between the front-end | tip part internal peripheral surface of the labyrin slip 33, and the outer peripheral surface of the step part 20 The labyrinth seal in the axial direction is formed. Further, the labyrinth slip 33 is inclined in a direction toward the radially outer side toward the outer side in the axial direction (tip side).

  Further, of the annular portion 35a constituting the core metal 30b by the sealing material 31b, a portion protruding radially outward from the outer peripheral edge of the axially outer end surface of the outer ring 2b, and the annular portion 35a By covering the cylindrical portion 37 that is bent inward in the axial direction from the outer edge, a flange portion 38 is formed. The inner diameter dimension of the flange portion 38 is larger than the outer diameter dimension of the outer peripheral surface of the outer end portion in the axial direction of the outer ring 2b, and the outer peripheral surface of the outer ring 2b, the inner side surface in the axial direction of the circular ring portion 35a, and the flange portion 38. A concave groove surrounded on three sides by the inner peripheral surface is formed over the entire outer peripheral surface of the outer end portion of the outer ring 2b. As a result, moisture that adheres to the outer peripheral surface of the outer ring 2b and tries to enter the labyrinth seal along the outer peripheral surface of the outer ring 2b can be blocked. Further, the sealing material 31b covers the inner surface in the axial direction of the annular portion 35a, and protrudes over the entire circumference on the inner surface in the axial direction of the annular portion 35a that contacts the outer end surface in the axial direction of the outer ring 2b. Article 39 is provided. This prevents foreign matters such as muddy water from entering the internal space 15 from the fitting surface between the outer ring 2b and the seal ring 14c.

  Further, the combined seal ring 19a incorporated in the wheel bearing rolling bearing unit 1b of the present embodiment is configured by combining a slinger 40a and a seal ring 41a as shown in FIG. The slinger 40a is formed by bending a metal plate to form an entire ring shape with an L-shaped cross section. The slinger 40a and the slinger cylinder 42 are radially outward from the axial inner edge of the slinger cylinder 42. It consists of a bent slinger ring part 43a. Such a slinger 40a is formed by fitting the slinger cylindrical portion 42 to the inner ring 3b by tightly fitting the inner ring 3b (the inner ring element 8 that constitutes the inner ring 3b together with the inner ring body 7b) with an interference fit. It is fixed. The seal ring 41a includes a metal plate cored bar 45a and an elastic material 46a. The elastic member 46a includes a plurality of (three in the illustrated example) seal lips 47a, 47b, 47c. The cored bar 45a is formed by bending a metal plate to have a substantially L-shaped cross section, and is formed into an annular shape as a whole. The diameter of the seal cylindrical part 48 and the axially outer edge of the seal cylindrical part 48 is reduced. The seal ring portion 49 is bent inward in the direction. The seal ring 41a provided with such a cored bar 45a is fixed to the outer ring 2b by fitting the seal cylinder 48 into the inner end in the axial direction of the outer ring 2b with an interference fit. In this state, the tip edge of the seal lip 47a is in sliding contact with the outer circumferential surface of the slinger cylindrical portion 42 and the tip edge of each seal lip 47b, 47c is in sliding contact with the entire outer circumference. I am letting.

  A ring-shaped encoder 17a is fixedly attached to the entire inner circumference of the inner surface in the axial direction of the slinger ring portion 43a constituting the slinger 40a. The encoder 17a is made of a permanent magnet, such as a rubber magnet or a plastic magnet, in which a magnetic powder is dispersed in a polymer material such as rubber or synthetic resin to form an annular shape as a whole. On the detection surface), the S poles and the N poles are alternately arranged at equal intervals in the circumferential direction. The encoder 17a is formed so as to cover the front end side peripheral edge (outer peripheral edge) of the slinger ring portion 43a, and between a part of the inner peripheral surface of the elastic member 46a covering the inner peripheral surface of the seal cylindrical portion 48, A labyrinth seal 52 is configured. Further, a part of the elastic member 46 a divides the radially outer side and the axially outer side by the inner peripheral surface of the seal cylindrical portion 48 and the outer diameter side half of the axial inner surface of the seal ring portion 49. A thick portion 53 having a radial thickness and an axial thickness dimension larger than the thickness dimension of other portions is provided in the portion. Then, the annular stepped surface 54 that is the inner end surface in the axial direction of the thick wall portion 53 and the portion that covers the portion near the tip of the inner peripheral surface of the seal cylindrical portion 48 are in a quarter arc shape. A certain outer diameter side curved surface 55 (corner R) makes it continue smoothly. The radius of curvature of the cross-sectional shape of the outer diameter side curved surface 55 is larger than the width dimension of the labyrinth seal 52 in the radial direction. This facilitates the return of foreign matter that has entered the space portion existing on the outer diameter side of the auxiliary seal lip 56 described below through the labyrinth seal 52 to the labyrinth seal 52 side.

  Furthermore, an auxiliary seal lip 56 is extended from the radially inner end of the step surface 54 toward the slinger ring portion 43a (formed integrally with the elastic material 46a together with the seal lips 47a to 47c). Further, the auxiliary seal lip 56 has a partially conical cylindrical shape extending obliquely toward the end in a direction in which the diameter increases inward in the axial direction with the stepped surface 54 as a base end. Such an outer peripheral surface of the base end portion of the auxiliary seal lip 56 and the stepped surface 54 are also smoothly continued by the inner diameter side curved surface 57 whose cross-sectional shape is a quarter arc. The radius of curvature of the cross-sectional shape of the inner diameter side curved surface 57 penetrates into the space portion existing on the outer diameter side of the auxiliary seal lip 56 through the labyrinth seal 52 from a surface that makes the auxiliary seal lip 56 easily moderately bent. In order to facilitate the return of foreign matter to the labyrinth seal 52 side, it is appropriately regulated. For this reason, the radius of curvature of the cross-sectional shape of the inner diameter side curved surface 57 is the same as or slightly larger than the thickness of the base end portion of the auxiliary seal lip 56.

  Such an auxiliary seal lip 56 has a role of suppressing foreign matter from adhering to a seal lip 47a near the outer space called a side lip, which exists on the inner diameter side of the auxiliary seal lip 56, and is a highly sophisticated seal. Sex is not required. Rather, it is important to suppress an increase in rotational resistance (dynamic torque) of the wheel bearing rolling bearing unit 1b incorporating the combination seal ring 19a by providing the auxiliary seal lip 56. For this reason, in the case of the present embodiment, an increase in sliding resistance due to the provision of the auxiliary seal lip 56 is suppressed by the following device.

The cross-sectional shape of the auxiliary seal lip 56 is wedge-shaped with the thickness dimension decreasing toward the tip edge. By doing so, the rigidity of the tip end portion of the auxiliary seal lip 56 is kept low so that the sliding resistance does not increase.
Furthermore, the thickness dimension of the auxiliary seal lip 56 is made sufficiently smaller than the thickness dimension of the seal lip 47a. Specifically, the thickness dimension of the base end portion, which is the thickest portion of the auxiliary seal lip 56, is ½ (half the thickness dimension of the base end portion, which is the thinnest portion of the seal lip 47a. ) Or less, more preferably 1/3 or less, but 1/5 or more in consideration of moldability. By doing so, the rigidity of the entire auxiliary seal lip 56 is kept low so that the sliding resistance does not increase.
Further, in a state where the seal ring 41a and the slinger 40a are combined, the tightening allowance of the auxiliary seal lip 56 is made sufficiently smaller than the tightening allowance of the seal lip 47a. In this way, the elastic deformation amount (axial compression amount) of the auxiliary seal lip 56 is made sufficiently smaller than the elastic deformation amount of the seal lip 47a in a state where the seal ring 41a and the slinger 40a are combined. The surface pressure of the sliding portion between the tip edge of the auxiliary seal lip 56 and the axially outer surface of the slinger ring portion 43a is suppressed so that the sliding resistance does not increase.

  Since the auxiliary seal lip 56 does not require a high degree of sealing performance, the tip of the auxiliary seal lip 56 is in a state where the central axis of the seal ring 41a and the central axis of the slinger 40a are inclined as the automobile turns. The edge may be slightly lifted from the axially outer side surface of the slinger ring portion 43a (even if the allowance is zero or there is a slight gap). Moreover, it is good also as a structure which makes the front-end edge of the auxiliary seal lip 56 oppose the axial direction outer side surface of the slinger ring part 43a over the perimeter via a micro clearance gap.

  In any case, the auxiliary seal lip 56 exists between the seal lip 47 a and the labyrinth seal 52, and the external space 58 is provided in a portion communicating with the labyrinth seal 52 on the outer space side of the auxiliary seal lip 56. Is provided. Both the radially inner and outer peripheral portions of the step surface 54 constituting the outer space 58 are smoothly continuous with the radially inner and outer peripheral surfaces of the outer space 58 by the outer diameter and inner diameter curved surfaces 55 and 57, respectively. I am letting. Furthermore, the outer peripheral surface of the auxiliary seal lip 56 continuing from the inner diameter side curved surface 57 is inclined in the direction toward the labyrinth seal 52 toward the tip. With such a configuration, the flow of foreign matter blown from the labyrinth seal 52 into the external space 58 is converted and returned to the labyrinth seal 52.

According to the wheel support rolling bearing unit 1b of the present embodiment incorporating the combination seal ring 19a configured as described above, the bearing is located on the bearing inner side with respect to the seal lip 47a between the slinger 40a and the seal ring 41a. It is possible to effectively prevent foreign matter such as muddy water from entering the seal internal space. In particular, among the seal lips 47a to 47c, foreign matter adheres to the outer peripheral surface of the seal lip 47a present in the portion closest to the labyrinth seal 52, and the behavior of the seal lip 47a is impaired, and the seal performance of the seal lip 47a is reduced. Can be prevented from decreasing. That is, the labyrinth seal 52 and the stepped surface 54 and the auxiliary seal lip 56 that partition the outer end surface and the inner peripheral surface in the axial direction of the outer side space 58 allow foreign matter to enter the space existing on the inner diameter side of the auxiliary seal lip 56. The entry is suppressed.
Since the configuration and operation of the other parts are the same as those in the first embodiment described above, the same parts are denoted by the same reference numerals, and redundant description is omitted.

  The wheel-supporting rolling bearing unit of the present invention can be suitably used as a bearing unit for supporting automobile wheels on a suspension device.

1, 1a, 1b Rolling bearing unit for wheel support 2, 2a, 2b Outer ring 3, 3a, 3b Inner ring 4, 4a, 4b, 4c, 4d Ball 5, 5a Static side flange 6, 6a, 6b, 6c, 6d Outer ring raceway 7, 7a, 7b Inner ring main body 8 Inner ring element 9 Clamping portion 10, 10a, 10b, 10c, 10d Inner ring raceway 11 Cage 12, 12a Rotating side flange 13 Stud 14, 14a-14c Seal ring 15 Internal space 16 Cover 17, 17a Encoder 18 Sensor 19, 19a Combination seal ring 20 Step portion 21 Sliding surface 22 Annular groove 23 Pilot portion 24, 24a Mounting hole 25 Small diameter step portion 26 Spline hole 27 Outer ring for constant velocity joint 28 Spline shaft 29 Nut 30, 30a, 30b Core metal 31, 31a, 31b Sealing material 32a, 32 Seal lip 33, 33a Labyrinth slip 34 Fitting cylinder part 35, 35a Circular ring part 36 Bending part 37 Cylindrical part 38 Gutter part 39 Projection 40, 40a Slinger 41, 41a Seal ring 42 Slinger cylindrical part 43, 43a Slinger annular part 44 collar 45, 45a core metal 46, 46a elastic material 47a, 47b, 47c seal lip 48 seal cylindrical part 49 seal ring part 50 fitting ring part 51 labyrin slip 52 labyrinth seal 53 thick part 54 step surface 55 outside Diameter side curved surface 56 Auxiliary seal lip 57 Inner diameter side curved surface 58 Small space near opening 59 Projection

Claims (1)

An outer ring having an outer ring raceway on the inner peripheral surface, an inner ring raceway in a portion of the outer peripheral surface facing the outer ring raceway, an inner ring disposed concentrically with the outer ring, and the outer ring raceway and the inner ring raceway. A plurality of rolling elements provided between the inner ring, a flange extending radially outward from the outer peripheral surface of the inner ring, and formed integrally with the inner ring by cold forging; and the outer ring A seal ring that closes an end opening of an internal space existing between an inner peripheral surface and the outer peripheral surface of the inner ring;
On the outer peripheral surface of the inner ring, a sliding surface that has been subjected to grinding is provided,
The seal ring includes a cored bar fixed to the end of the outer ring and an elastic sealant reinforced by the cored bar, and the sealant is slid over the entire circumference on the sliding surface. At least one seal lip that moves, and is provided further radially outward than the seal lip, with its tip facing the flange side surface in close proximity to the entire circumference, A rolling bearing unit for supporting a wheel provided with a labyrinth slip forming a labyrinth seal therebetween,
A step portion is formed between the forging surface of cold forging and the sliding surface on the side surface of the flange near the proximal end, and the leading end portion of the labyrin slip is more radially outward than the step portion. A rolling bearing unit for supporting a wheel, characterized in that the tip end portion of the labyrin slip and the stepped portion are overlapped in the radial direction.