JP4826538B2 - Wheel support bearing unit - Google Patents

Description

  The present invention relates to a wheel support bearing unit that rotatably supports a wheel of an automobile or a railway vehicle with respect to a vehicle body, and more particularly, to an improvement in a sealing structure of the wheel support bearing unit.

Conventionally, various hub unit bearings (wheel support bearing units (hereinafter simply referred to as bearing units)) for supporting wheels of various vehicles such as automobiles and railway vehicles are known.
For example, FIG. 6 illustrates a configuration of a hub unit bearing (hereinafter referred to as a bearing unit A) for rotatably supporting the wheels of an automobile as an example of the configuration of such a bearing unit.

  The bearing unit A includes a stationary wheel 2 fixed to a vehicle body (a knuckle (not shown) of a suspension device) and a rotating wheel 4 fixed to a wheel (a disk wheel (not shown)) and rotating together with the disk wheel. I have. Further, in the bearing unit A, a plurality of rolling elements (balls) 20 roll between the double-row (two rows) raceway surfaces 6 and 8 formed on the stationary wheel 2 and the rotating wheel 4 respectively. Embedded as possible. In this case, the rolling elements (balls) 20 roll between the raceway surfaces 6 and 8 in a state where the rolling elements (balls) 20 are rotatably held one by one in a pocket formed in the annular cage 22.

  In this case, the stationary wheel 2 is integrally formed with a fixing flange 2f that protrudes outward (in the direction of increasing the diameter) from the outer peripheral surface thereof, and is fixed to a fixing hole 2h that passes through the fixing flange 2f. By inserting a bolt (not shown) and fastening it to the vehicle body side, the stationary wheel 2 can be fixed to a knuckle of a suspension device (suspension) not shown.

  On the other hand, the rotating wheel 4 is provided with a hub 10 having a substantially cylindrical shape, and the hub 10 is fixed to a disc wheel (not shown) of a wheel via a brake rotor (not shown) of a brake. It is configured to rotate with the disc wheel. The hub 10 is fixed (externally fitted) with a brake rotor and a disc wheel on one side (wheel side (left side in FIG. 6), hereinafter referred to as the outboard side) in the axial direction (left-right direction in FIG. 6). The hub flange 10f for projecting is projected continuously along the circumferential direction.

  In this case, the hub flange 10f extends outward (in the diameter-enlarging direction of the hub 10) beyond the stationary ring 2, and a plurality of through-holes (in the circumferential direction) are provided in the vicinity of the extended edge. Bolt hole) 10h is provided. A brake rotor and a disc wheel (not shown) are each provided with a plurality of through holes (as an example, the same number as the bolt holes 10h) that can communicate with the bolt holes 10h. Then, the brake rotor and the disc wheel can be positioned and fixed with respect to the hub flange 10f by inserting the hub bolt 10b from the bolt hole 10h into the through hole and fastening (fastening) with a hub nut (not shown). it can.

In addition, an annular inner ring structural body 12 is externally fitted to the hub 10 on the other side (the inner side of the vehicle body (the right side in FIG. 6), hereinafter referred to as the inboard side) in the axial direction (left-right direction in FIG. 6). For example, in a state where a plurality of rolling elements 20 are held by the cage 22 between the stationary wheel 2 and the rotating wheel 4, the inner ring structure 12 is externally fitted to the step portion formed on the hub 10. Thereafter, the inner ring constituting body 12 can be fixed to the inboard side of the hub 10 by caulking the inboard side end of the hub 10 (right end in the figure), and the bearing unit A (more specifically, Can give a predetermined preload to the rolling elements (balls) 20). Here, the inner ring constituting body 12 is a member that forms a raceway surface 8 that faces the raceway surface 6 on the inboard side of the stationary wheel 2 and constitutes the rotating wheel 4 together with the hub 10.
Instead of the above-described caulking and fixing, for example, after the inner ring constituting body 12 is externally fitted to the step formed on the hub 10, the inner ring is tightened by a fastening member such as a nut from the inboard side. In some cases, the structure 12 is fixed to the inboard side of the hub 10.

  By the way, the bearing unit A is provided with various sealing devices for shielding the inside of the unit from the outside and keeping the sealed state (airtight state and liquid-tight state). In addition to preventing foreign matter (e.g., muddy water, dust, etc.) from entering the bearing unit from the outside, lubricant (e.g., grease, lubricating oil, etc.) enclosed inside leaks to the outside. Is preventing.

  In the configuration shown in FIG. 6, a disc-like cover member (hereinafter referred to as an inboard cap) 26 is provided on the inboard side of the bearing unit A, whereas a seal member (hereinafter referred to as an inboard cap) is provided on the outboard side. An outboard seal (24) is provided, and by providing the inboard cap 26 and the outboard seal 24, the sealing performance (airtightness and liquid tightness) inside the unit is maintained.

  Conventionally, various bearing unit configurations in which such an outboard seal 24 is disposed on the outboard side are known. For example, in Patent Document 1, as shown in FIG. A seal portion 24b made of various elastic materials (for example, a resin material such as rubber or plastic) is connected to a part of an annular cored bar 24a formed by pressing or the like, and a plurality (for example, 3 A configuration of the outboard seal 24 having a structure provided with a lip 24c is disclosed as an example.

In this case, the outboard seal 24 is attached to the end portion on the outboard side of the surface facing the rotating wheel 4 (specifically, the hub 10) of the stationary wheel 2, and the lip 24c of the seal portion 24b is the hub. It is positioned so as to be in sliding contact with a base portion (hereinafter referred to as a sliding contact surface) 10s of the flange 10f. Specifically, the lip 24c of the seal portion 24b extends along the curve of the slidable contact surface 10s having a concave curved surface shape, and is in slidable contact with the slidable contact surface 10s along the curve.
Therefore, the outboard seal 24 has a feature that the axial dimension of the seal portion 24b (the distance in the left-right direction in FIG. 7A) is reduced, that is, it is easy to make compact, and the lip 24c is It has the feature of being difficult to reverse.

  On the other hand, when water is immersed between the end face 2c on the outboard side of the stationary wheel 2 and the hub flange 10f, the water is directly applied to the sliding contact portion of the outer lip 24c with respect to the sliding contact surface 10s. The outer lip 24c refers to a lip (upper left lip in FIG. 7) that is in slidable contact with the sliding contact surface 10s on the outermost side among the three lips 24c shown in FIG. Therefore, in order to prevent such water from leaking to the inside of the bearing unit A, it is necessary to set the surface pressure (so-called crimping margin) against the sliding contact surface 10s of the outer lip 24c to a certain extent.

For this reason, the rotational torque of the outboard seal 24 increases, and the rotational accuracy of the bearing unit A may be deteriorated depending on the degree of the torque increase. The outer lip 24c has a large sliding diameter D2, and the rotational torque of the outboard seal 24 tends to increase.
In other words, since the difference between the outer diameter of the outer lip 24c and the outer diameter of the cored bar 24a is small, a press-fitting surface (specifically, when the outboard seal 24 is press-fitted into the stationary ring 2 is specified. Therefore, the diameter difference H2 between the cored bar 24a and the outer lip 24c shown in FIG. 7B becomes small, and the press-fitting work becomes difficult.
JP 2005-155882 A

In order to avoid such an inconvenience, the following measures can be taken.
For example, as shown in FIG. 7C, a predetermined sliding member (hereinafter referred to as a slinger) 30 along the curve of the sliding contact surface 10s with respect to the rotating wheel 4 (specifically, the hub 10). May be provided. By providing the slinger 30, the lip 24 c (outer lip 24 c) of the outboard seal 24 is in sliding contact with the outer peripheral surface 30 s of the slinger 30. Further, the slinger 30 is opposed to the outer end lip 24c at a predetermined distance from the outer end (the upper left end in the figure) of the slinger 30 with a cylindrical portion 30a for shielding the outer lip 24c from the outside of the bearing unit A. It is formed to do.

Thereby, it is possible to prevent water from directly entering the sliding contact portion between the outer lip 24c and the outer peripheral surface 30s. As a result, the surface pressure (tightening allowance) with respect to the outer peripheral surface 30s of the outer lip 24c can be set small, and an increase in the rotational torque of the outboard seal 24 can be suppressed.
However, since the manufacturing process and attachment process of this slinger 30 are needed separately, the extra cost will arise.

  For example, as shown in FIG. 7D, the sliding contact surface 10s of the rotating wheel 4 (specifically, the hub 10) can accommodate the lip 24c (outer lip 24c) of the outboard seal 24. What is necessary is just to make it the structure dented by the magnitude | size. By making the sliding contact surface 10s have such a structure, the lip 24c (outer lip 24c) is in sliding contact with the recess 10b of the sliding contact surface 10s, and the sliding contact portion between the outer lip 24c and the recess 10b is submerged. Can be prevented directly. As a result, the surface pressure (crimping allowance) with respect to the recess 10b of the outer lip 24c can be set small, and an increase in the rotational torque of the outboard seal 24 can be suppressed.

  Here, generally, the sliding contact surface 10 s of the rotating wheel 4 (specifically, the hub 10) is formed by grinding the track surface 8 at the same time as grinding. ing. However, when forming the hollow part 10b with respect to the sliding contact surface 10s, such simultaneous grinding cannot be performed, and only the sliding contact surface 10s itself or the hollow part 10b is formed (processed) in a separate work process. Therefore, extra costs will be incurred.

  The present invention has been made in order to solve such a problem, and its object is to provide a sealing structure that has excellent sealing performance, can reduce rotational torque, and is easy to introduce. The object is to provide a wheel-supporting bearing unit provided.

In order to achieve such an object, a wheel support bearing unit according to the present invention includes a stationary wheel fixed to a vehicle body constituent member, a rotating wheel to which the wheel constituent member is fixed and rotates together with the wheel constituent member, A plurality of rolling elements which are formed on the stationary wheel and the rotating wheel, respectively, and are incorporated so as to be able to roll between the mutually facing double-row raceway surfaces, and interposed between the stationary wheel and the rotating wheel, Is equipped with a sealing device for keeping the airtight and liquid-tight. In such a wheel support bearing unit, the sealing device has an annular shape composed of a cylindrical fixed portion extending in a predetermined direction and an annular portion extending continuously from the extended end on one side of the fixed portion. A core bar, and a seal connected to the core bar and provided with a plurality of lips extending so as to be in sliding contact with the rotating wheel. The seal includes an extended portion in which a lip that is in sliding contact with the rotating wheel on the outermost side extends in a cylindrical shape substantially parallel to the axial direction, and a portion inside the bearing from the extended end of the extended portion It is composed of a sliding contact portion that is continuously projected over the entire circumference of the inner peripheral surface of the part so as to reduce the inner diameter dimension of the part, and is fixed to the stationary wheel via the cored bar. In this state, the sliding contact portion is brought into sliding contact with the outer peripheral portion of the rotating wheel while the extending end of the extending portion is opposed to the outer peripheral portion of the rotating wheel at a predetermined interval with respect to the radial direction . The extension end of the extension portion protrudes toward the wheel component member side from the end surface of the stationary wheel on the wheel component member side, and the extension end is the outer periphery of the rotating wheel. It is positioned so as to face the part with a predetermined interval with respect to the axial direction. Then, when the distance between the extending end of the extending portion and the outer peripheral portion of the rotating wheel in the axial direction is A1, and the protruding height of the sliding contact portion is B1, the relationship of A1 <B1 is set.

When the stationary wheel, the cage, and the rolling element are assembled to the rotating wheel, two assembly jigs that form a substantially semi-annular shape are connected to the end surface of the stationary wheel on the wheel component member side and the rotating wheel. If it is inserted into the gap between the outer periphery of the ring and the extension part is guided by these assembling jigs, the lip of the seal that slides on the outermost side with the rotating wheel is positioned. Good. Note that after the assembly work is completed, the assembly jig may be removed from the gap.

  According to the wheel support bearing unit of the present invention, a sealing structure having excellent sealing performance can be easily introduced, and the rotational torque can be greatly reduced, resulting in a reduction in fuel consumption of the vehicle. It is also possible.

  A wheel support bearing unit (hereinafter simply referred to as a bearing unit) according to the present invention will be described below with reference to the accompanying drawings. The wheel support bearing unit according to the present invention can be applied as a bearing unit that rotatably supports the wheels of various vehicles such as automobiles and railway vehicles. The case where it is applied as a hub unit bearing is assumed as an example. In this case, it is assumed that the basic configuration of the bearing unit according to the present invention is the same as that of the conventional bearing unit A (FIG. 6) described above. Omitted or simplified, and the characteristic configuration of the present invention will be described below.

  Such a bearing unit is a driven wheel of an automobile as shown in FIG. 6 (front wheel of a front engine rear wheel drive (FR) vehicle and rear engine rear wheel drive (RR) vehicle, front engine front wheel drive (FF)). It may be configured as a hub unit bearing that supports the rear wheels of the vehicle, or drive wheels of automobiles (rear wheels of FR and RR vehicles, front wheels of FF vehicles, and all wheels of four-wheel drive (4WD) vehicles) You may comprise as a hub unit bearing to support.

1 (a) and 1 (b) show a sealing structure on one side (wheel side (left side in the figure), hereinafter referred to as outboard side) of the bearing unit X according to an embodiment of the present invention in the axial direction. It is shown.
The bearing unit X includes a stationary wheel 40 fixed to a vehicle body (a knuckle (not shown) of a suspension device) and a rotating wheel 42 fixed to a wheel (a disk wheel (not shown)) and rotating together with the disk wheel. Are formed on the stationary wheel 40 and the rotating wheel 42 so as to roll between the raceway surfaces 40a, 42a of two rows (as an example, two rows (only the outboard side is shown)) facing each other. A plurality of rolling elements (balls) 44 and a sealing device 46 for keeping the inside airtight and liquid-tight are provided.

In this case, the rolling elements (balls) 44 roll between the raceway surfaces 40a and 42a in a state in which the rolling elements (balls) 44 are rotatably held one by one in a pocket formed in an annular retainer (not shown). Thereby, each rolling element 44 can roll between the raceway surfaces 40a and 42a without the rolling surfaces being in contact with each other. As a result, the rolling elements 44 are in contact with each other and friction is generated. It is possible to prevent an increase in rotational resistance and seizure caused by the occurrence. Note that a lubricant (for example, grease) is enclosed inside the bearing unit X in order to more effectively prevent such an increase in rotational resistance and seizure.
Here, FIG. 1A shows an example of a configuration in which a ball is applied as the rolling element 44. However, as the rolling element 44, various rollers (cylindrical rollers, tapered rollers, and spherical rollers are used instead of the balls). Etc.) may be applied.

  In the present embodiment, the sealing device (hereinafter referred to as “outboard seal”) 46 includes an annular cored bar 50 and a seal 60 connected to the cored bar 50. In this case, the cored bar 50 includes a cylindrical fixing portion 52 that extends in a predetermined direction, and an annular portion 54 that extends continuously from an extension end on one side of the fixing portion 52. On the other hand, the seal 60 is provided with a plurality of lips 60 l extending so as to be in sliding contact with the rotating wheel 42.

As an example, in the configuration shown in FIG. 1A, the cored bar 50 has a cylindrical shape in which the fixing portion 52 extends in a predetermined direction (the left-right direction in the figure) with a predetermined length (distance in the same direction in the figure). While being formed, the annular portion 54 is composed of three parts: a base end part 54a, a connecting part 54b, and a front end part 54c. Specifically, a predetermined length (the distance in the vertical direction in the figure) from the extending end on one side of the fixed portion 52 (the left end in FIG. 1 (a)) substantially perpendicular to the diameter reducing direction (downward in the figure). ), The base end portion 54a is extended and then tilted forward from the base end portion 54a to the inboard side (the right side in the figure) (with an internal angle with the base end portion 54a forming an obtuse angle). The connecting portion 54b is extended, and the tip portion 54c is extended from the connecting portion 54b with a predetermined length substantially perpendicular to the diameter reducing direction, thereby forming an annular portion 54.
The core metal 50 having such a configuration is press-fitted and fixed (specifically, fitted) to the stationary wheel 40 of the bearing unit X, and is always kept stationary.

Here, the size (extension length, thickness (distance in the vertical direction in FIG. 1A) and diameter, etc.) and shape of the fixing portion 52, the shape, and the annular portion 54 (base end portion 54a, connection) The size (extension length, thickness (distance in the left and right direction in the figure) and diameter, etc.) and shape of the portion 54b and the tip portion 54c), the shape, etc. are, for example, the stationary wheel 40 and the rotating wheel of the bearing unit X Since it is arbitrarily set according to the size and shape of 42, it is not particularly limited.
Furthermore, the material and the forming method of the cored bar 50 are not particularly limited. For example, the cored bar 50 is made of a predetermined metal plate (made of a steel plate) and may be formed by pressing the metal plate (steel plate). .

  In the configuration shown in FIG. 1 (a), as an example, a step portion 40g formed by continuously cutting the end portion on the outboard side of the inner peripheral surface 40b of the stationary wheel 40 over the entire circumference into a concave shape. Is provided, and the outboard seal 46 is assembled by fixing (fitting) the fixing portion 52 of the cored bar 50 to the stepped portion 40g.

The size (width (distance in the left-right direction in FIG. 1A) and depth (distance in the vertical direction in FIG. 1)) and shape of the stepped portion 40g are not particularly limited. What is necessary is just to set arbitrarily according to a magnitude | size, a shape, a magnitude | size, a shape, etc. of the sealing device 46 (core metal 50). As an example, in the configuration shown in FIG. 1A, the width of the stepped portion 40g is set to a dimension larger than the extension length of the fixing portion 52 of the cored bar 50 (the distance in the left-right direction in the figure). In addition, the depth is set to be approximately the same as the thickness of the fixing portion 52 (the vertical distance in the figure).
With this configuration, the entire fixing portion 52 of the cored bar 50 can be disposed with respect to the stepped portion 40g, and the fixed portion 52 of the cored bar 50 and the stepped portion 40g of the stationary ring 40 are in contact with each other. The contact area (fitting area) can be increased.

  As a result, the fitting force of the metal core 50 to the stationary wheel 40 can be increased, and the lubricant that flows from the row of rolling elements (balls) 44 to the outboard side after assembly to the bearing unit X (as an example, grease). Thus, even when a pressing force (a pressing force in the external direction of the bearing unit (the left direction in FIG. 1A)) acts on the outboard seal 46, it is possible to sufficiently counter the pressing force. Therefore, it is possible to prevent the metal core 50 from moving (that is, misaligned) in the direction outside the bearing unit X (the left direction in FIG. 1A), and the sealing performance of the outboard seal 46 is always constant. Can be kept in.

  In this case, the outboard seal 46 is provided with a fitting allowance for fitting to the stationary wheel 40 with respect to the inner diameter dimension (specifically, the inner diameter dimension of the fixing portion 52 of the cored bar 50). ing. That is, the outboard seal 46 is configured such that the inner diameter dimension of the fixing portion 52 of the cored bar 50 is set to be larger than the diameter dimension of the stepped portion 40g portion of the stationary ring 40 by the fitting allowance. . At that time, the fitting allowance to be set to the fixing portion 52 of the cored bar 50 is not particularly limited because it may be arbitrarily set according to the size of the stationary wheel 40 or the like.

  Further, in the configuration shown in FIG. 1A, a stepped portion 40g is provided in the stationary wheel 40, and the cored bar 50 (fixed portion 52) is fixed (fitted) to the stepped portion 40g, whereby the outboard seal 46 is provided. For example, the fixing portion 52 of the cored bar 50 is fixed (fitted) to the end portion on the outboard side of the inner peripheral surface 40b of the stationary ring 40 without providing such a stepped portion 40g. Thus, a structure in which the outboard seal 46 is assembled to the stationary wheel 40 may be employed. Note that the fixing portion 52 of the core metal 50 may be bonded and fixed to the end portion on the outboard side of the inner peripheral surface 40b of the stationary ring 40 with a predetermined adhesive or the like, for example.

  Further, in the configuration shown in FIG. 1A, the seal 60 has a core metal 50, specifically, an outer surface of the annular portion 54 (base end portion 54a, connecting portion 54b, and tip portion 54c) (the left side of the figure). A plurality of (for example, three) lips 62l, 64l, 66l toward the inboard side (hereinafter referred to as the peripheral surface) 42s of the base portion of the hub flange 42f provided on the rotating wheel 42. The lips 62l, 64l, 66l are in sliding contact with the peripheral surface 42s of the rotating wheel 42.

  In this case, the seal 60 has a lip (hereinafter referred to as an outer lip) 62l slidably in contact with the peripheral surface 42s of the rotating wheel 42 on the outermost side (upper left side of FIG. An extending portion 62s extending in a substantially parallel and cylindrical shape, and a slide continuously projecting over the entire circumference of the inner peripheral surface so as to reduce the inner diameter of the extending portion 62s. It is comprised with the contact part 62t. A lip (hereinafter referred to as an inner lip) 66l slidably in contact with the peripheral surface 42s of the rotating wheel 42 on the innermost side (lower right side in the figure) is directed toward the inner side (lower side in the figure) of the bearing unit X. It is configured to extend. Of the three lips 60l provided on the seal 60, a lip (hereinafter referred to as an intermediate lip) 64l positioned in the middle is, as an example, outward of the bearing unit X (above FIG. 1 (a)). The front end of the rotating wheel 42 is in sliding contact with the outer circumferential surface 42s of the rotating wheel 42. However, the intermediate lip 64l extends inward of the bearing unit X (downward in FIG. 1 (a)), and its tip end is in sliding contact with the peripheral surface 42s of the rotating wheel 42 inward. You may comprise.

  With such a configuration of the seal 60, the outer lip 62l and the intermediate lip 64l can prevent foreign matter (for example, muddy water or dust) from entering the inside of the bearing unit X from the outside to the inside. Leakage of lubricant (as an example, grease) from the inside of X to the outside can be prevented by the inner lip 66l. Thereby, the seal 60 can effectively shield the inside of the bearing unit X from the outside, and can always keep the inside of the unit in a sealed state (airtight state and liquid-tight state).

In the configuration shown in FIG. 1A, as an example, the extending portion 62s has a predetermined length (distance in the left-right direction in the figure) at a substantially right angle toward the outboard side with respect to the connecting portion 54b of the annular portion 54. It has been extended. At this time, the extension length of the extension portion 62 s is such that the extension end 62 v of the extension portion 62 s is the outer peripheral portion of the rotating wheel 42 in a state where the seal 60 is fixed to the stationary wheel 40 via the core metal 50. What is necessary is just to set to the dimension which can oppose (circumferential surface 42s) at predetermined intervals.
The extending part 62s is not necessarily perpendicular to the connecting part 54b of the annular part 54, that is, extends to the outboard side substantially parallel to the axial direction (the left-right direction in FIG. 1A). It is not necessary to let it go out. For example, the extending portion 62s may be configured to extend from the connecting portion 54b so as to have an upward gradient or a downward gradient toward the outboard side.

  Further, the size, shape, number, arrangement position, and the like of the sliding contact portion 62t may be arbitrarily set according to the size of the extending portion 62s, the shape of the peripheral surface 42s of the rotating wheel 42, and the like. As an example, FIG. 1A illustrates a configuration of the sliding contact portion 62t formed in a trapezoidal shape with a tapered cross-sectional shape, but the shape is not particularly limited thereto. For example, the slidable contact portion 62t may be formed in a trapezoidal shape with a cross section, a triangular shape, a rectangular shape, a convex shape, or a shape branched into two or more.

  Further, in the configuration shown in FIG. 1 (a), the sliding contact portion 62t is positioned at a substantially middle portion of the extension dimension of the inner peripheral surface of the extension portion 62s. The sliding end 62t may be positioned at the extended end (left end in the figure) or the base end (right end in the figure). Further, the number of sliding contact portions 62t is not limited to one, and a plurality (several strips) may be provided. In that case, the shape (cross-sectional contour shape) of all the sliding contact portions 62t may be the same or different.

  The sliding contact portion 62t is positioned so as to be in sliding contact with the outer peripheral portion (the peripheral surface 42s) of the rotating wheel 42 in a state where the seal 60 is fixed to the stationary wheel 40 via the cored bar 50. That is, the protruding height (distance B1 shown in FIG. 1A) of the sliding contact portion 62t is in contact with the outer peripheral portion (the peripheral surface 42s) of the rotating wheel 42 (sliding contact) in such a fixed state of the seal 60. It may be set to a predetermined size possible. However, the protruding height B1 of the sliding contact portion 62t is the distance between the extended end 62v of the outer lip 62l and the inner surface (surface on the inboard side (the surface on the right side in FIG. 1A)) 42i of the hub flange 42f. It is preferable to set it larger than (distance A1 shown in the figure) (dimension A1 <B1 in the figure). Thus, by setting A1 <B1, the entrance of the labyrinth formed between the extended end 62v of the outer lip 62l and the inner surface 42i of the hub flange 42f is narrowed, and the space inside is widened. The effect can be enhanced.

As the material of the seal 60, various elastic materials (for example, resin materials such as rubber and plastic) may be arbitrarily selected and applied according to the material of the core metal 50 and the like. Further, the number and shape of the lips 60l provided on the seal 60 are not limited to the configuration shown in FIG. 1A. For example, two lips 60l may be provided on the seal 60, or four or more lips may be provided. The lip 60l may be provided. Furthermore, the core metal 50 and the seal 60 (various elastic materials) may be connected by arbitrarily selecting various methods such as adhesion, caulking, coating, injection molding, and vulcanization molding.
However, in any case, at least the lip (that is, the outer lip) slidably in contact with the peripheral surface 42s of the rotating wheel 42 on the outermost side (the upper left side in FIG. 1A) has an axial direction (the left-right direction in the figure). ) Extending in a cylindrical shape substantially in parallel with the sliding portion, and a slid protruding continuously over the entire circumference of the inner peripheral surface so as to reduce the inner diameter of the extending portion. What is necessary is just to provide a contact part.

  In the configuration shown in FIG. 1A, the peripheral surface 42s of the rotating wheel 42 with which the lip 60l of the seal 60 is in sliding contact has a concave curved surface shape, and the concave curved surface 42c is provided with a predetermined step. It is continued to the inner surface 42i of the hub flange 42f via a formed step surface (hereinafter referred to as a sliding contact surface) 42d. In this case, the step of the peripheral surface 42s is such that the sliding contact surface 42d is substantially parallel to the axial direction (the left-right direction in FIG. 1A), specifically, the outer peripheral portion of the rotating wheel 42, specifically, the hub flange 42f. It is continuously provided over the entire circumference to the inboard side of the root portion.

  With such a configuration of the peripheral surface 42s, of the three lips 60l of the seal 60, the intermediate lip 64l and the inner lip 66l are in sliding contact with the concave curved surface 42c, whereas the outer lip 62l is in sliding contact. 42d is in sliding contact. That is, the outer lip 62l extends along the slidable contact surface 42d with the extended portion 62s spaced from the slidable contact surface 42d, and the extended end 62v is connected to the root portion (the inner surface 42i) of the hub flange 42f. ) With a predetermined interval. The outer lip 62l has a structure in which the sliding contact portion 62t is in sliding contact with the sliding contact surface 42d from a substantially vertical direction (radial direction).

  That is, by this, even if the water is temporarily submerged from between the end surface 40c on the outboard side of the stationary wheel 40 and the inner surface 42i of the hub flange 42f, the submerged water is extended to the extended portion 62s (specifically, the outer lip 62l). Therefore, it is possible to prevent the water from being directly applied to the sliding contact portion of the sliding contact portion 62t with respect to the sliding contact surface 42d. Therefore, even if the surface pressure (so-called crimping margin) with respect to the sliding contact surface 42d of the sliding contact portion 62t is set to be relatively small, it is possible to reliably prevent water from entering the unit from the sliding contact portion.

Further, the sliding contact portion 62t of the outer lip 62l is in sliding contact with the sliding contact surface 42d from a substantially vertical direction (radial direction), so that the sliding of the outer lip 62l (specifically, the sliding contact portion 62t) is performed. The moving diameter D1 can be reduced (for example, D1 <D2 in the relationship with the sliding diameter D2 of the outer lip 24c in the sealing structure of the conventional bearing unit A described above).
As a result, the rotational torque of the outboard seal 46 can be reduced, and consequently the rotational torque of the bearing unit X can be reduced, and the rotational accuracy can be easily increased.

  Similarly, the outer diameter dimension of the outer lip 62l and the outer diameter dimension of the cored bar 50 are configured by the structure in which the sliding contact portion 62t of the outer lip 62l is in sliding contact with the sliding contact surface 42d from a substantially vertical direction (radial direction). More specifically, the difference between the outer diameter dimension of the extending part 62s and the outer diameter dimension of the fixed part 52 can be increased. Therefore, the press-fitting surface when the outboard seal 46 is press-fitted into the stationary wheel 40 (specifically, the diameter difference between the fixed portion 52 of the cored bar 50 and the extended portion 62s of the outer lip 62l shown in FIG. 1B). By increasing H1), the press-fitting operation can be performed very smoothly.

At this time, the extending portion 62s of the outer lip 62l extends from the vicinity of the extending end of the connecting portion 54b of the annular portion 54 (near the lower end of FIG. 1B) to the outboard side. It is preferable to do. Thereby, the diameter difference H1 between the fixing portion 52 of the core metal 50 and the extending portion 62s of the outer lip 62l can be set larger.
Further, it is preferable that the facing distance (distance A1 shown in FIG. 1A) between the extending end 62v of the extending portion 62s and the root portion (inner surface 42i) of the hub flange 42f is set as narrow as possible. . As a result, a labyrinth can be formed between the extended end 62v and the base portion (inner surface 42i) of the hub flange 42f, and the sliding contact portion 62t can come into contact with the sliding contact surface 42d from the outside of the unit. Inundation itself can be effectively prevented.

As described above, according to the wheel support bearing unit (bearing unit X) according to the present embodiment, a sealing structure having excellent sealing performance can be easily introduced, and the rotational torque can be significantly reduced. .
As a result, it becomes possible to continue rotating the bearing unit X with a certain accuracy over a long period of time, and as a result, it is possible to reduce the fuel consumption of the automobile.

  Here, the outboard seal 46 having the above-described structure is assembled to a stationary ring 40 integrated with a rolling element (ball) 44 held by a cage (not shown), and an assembly of the bearing unit X. Configure. After the assembly is assembled to the rotating wheel 42 (specifically, the hub 10 (FIG. 6)), the inner ring component 12 (the same figure) is assembled to the hub 10, and these are integrated. By combining them, the bearing unit X can be assembled.

  At this time, in addition to the configuration according to the present embodiment as described above, the bearing unit X is configured as described below so that the assembly body is connected to the rotating wheel 42 (hub 10 (FIG. 6)). ) (Hereinafter, such work is referred to as assembly work), it is possible to effectively prevent the outer lip 62l (the extended portion 62s and the sliding contact portion 62t) of the seal 60 from being reversed. In this case, each of the following configurations may be individually added to the configuration according to the present embodiment (FIGS. 1A and 1B), or may be arbitrarily selected and combined in the present embodiment. You may add to such a structure (FIG. 1 (a), (b)).

  As shown in FIG. 1A, in the state where the outboard seal 46 is fixed to the stationary wheel 40 via the cored bar 50, the extending end 62v of the extending portion 62s is connected to the stationary wheel 40. It is preferably positioned so as to protrude toward the outboard side from the end surface 40c on the outboard side.

  That is, with this configuration, when the assembling work is performed, the state of the extended portion 62s of the outer lip 62l, particularly the state of the extended end 62v, is set to the end surface 40c of the stationary wheel 40 and the hub of the rotating wheel 40. It can be visually confirmed from a gap between the inner surface 42i of the flange 42f (hereinafter referred to as an assembly gap). Thereby, at the time of the assembly work, it is possible to perform the assembly work while confirming the state of the extended portion 62s (particularly, the extended end 62v) of the outer lip 62l by visual observation. As a result, it is possible to effectively prevent the outer lip 621 (the extending portion 62s and the sliding contact portion 62t) of the seal 60 from being reversed in the assembling operation.

  Further, by projecting the extended end 62v to the outboard side from the end face 40c in this way, a predetermined jig (hereinafter referred to as an assembly jig) 80 is inserted from the assembly gap as shown in FIG. Assembly work can be performed in the inserted state. At that time, since the insertion position of the assembly jig 80 can be visually confirmed, the insertion operation can be performed easily and accurately.

  In the configuration shown in FIG. 2, as an example, the assembling jig 80 is constituted by two plate members 80a and 80b having a substantially semi-annular shape, and the inner diameter dimension thereof is the extension portion 62s of the outer lip 62l. The dimension is set to be slightly larger than the outer diameter dimension, and the thickness dimension (the distance in the left-right direction in the figure) is set to be smaller than the interval dimension of the assembly gap. Thereby, before the assembly work, when the assembly work is performed by inserting the assembly jig 80 (80a, 80b) in advance into the assembly gap from the radial direction and combining them in a substantially annular shape, The extended portion 62s of the outer lip 62l can be guided to a predetermined position over substantially the entire circumference, and the sliding contact portion 62t is in sliding contact with the sliding contact surface 42d of the rotating wheel 42 from a substantially vertical direction (radial direction). The outer lip 62l can be easily positioned. Note that after the assembly work is completed, the assembly jig 80 (80a, 80b) inserted into the assembly gap may be removed.

  Accordingly, the assembling work can be performed in a state where the extending portion 62s of the outer lip 62l is guided by the assembling jig 80 (80a, 80b), and therefore the outer lip 62l (the extending portion 62s and the extending portion 62s of the seal 60). It is possible to effectively prevent the sliding contact portion 62t) from being reversed.

  Further, in the above-described embodiment, as shown in FIG. 1A, the sliding contact surface 42d of the rotating wheel 42 is formed so as to be substantially parallel to the axial direction (the left-right direction in the figure). However, for example, as shown in FIG. 3 (a), it is inclined (tapered) ascending with respect to the moving direction (left direction in the figure) of the extending portion 62s of the outer lip 62l during assembly work. It is more preferable that the sliding contact surface 42d is formed on the surface.

That is, with this configuration, when the assembly work is performed, the sliding contact portion 62t of the outer lip 62l first comes into contact with the lower portion of the tapered sliding contact surface 42d, and gradually the sliding contact surface 42d. Ascending the ridgeline part. Thus, the outer lip 621 can be positioned while gradually increasing the surface pressure of the slidable contact portion 62t of the outer lip 621 against the slidable contact surface 42d. Therefore, the outer lip 621 (the extended portion 62s and the slidable contact of the seal 60) can be positioned. It is possible to effectively prevent the portion 62t) from being inverted.
In addition, since the magnitude | size of a gradient, the length of a ridgeline part, etc. should just be arbitrarily set according to the extension length of the extension part 62s of the outer side lip 62l, the magnitude | size of the sliding contact part 62t, etc. here, especially here Not limited.

  Alternatively, as shown in FIG. 3B, the slidable contact surface 42d of the rotating wheel 42 has a stepped structure, and the slidable contact portion 62t of the outer lip 62l gets over the predetermined step 42g during assembly work. The outer lip 62l may be positioned. In this case, the sliding contact surface 42d is relatively closer to the front side of the step 42g with respect to the moving direction of the outer lip 62l during assembly work (the direction from right to left in FIG. 3B). A portion d1 having a small diameter is formed, and a portion d2 having a relatively large diameter is formed on the back side.

That is, when the sliding contact surface 42d has such a stepped structure, when the assembly work is performed, the sliding contact portion 62t of the outer lip 62l first comes into contact with the lower portion d1 of the sliding contact surface 42d, and gradually. It moves toward the step 42g, gets over the step 42g, and comes into contact with the high portion d2 of the sliding contact surface 42d. Accordingly, the outer lip 62l can be positioned while the surface pressure of the sliding contact portion 62t with respect to the sliding contact surface 42d is increased stepwise before and after the step 42g, so that the outer lip 62l (extension portion 62s and It is possible to effectively prevent the sliding contact portion 62t) from being reversed.
The size and height of the step 42g may be arbitrarily set according to the extension length of the extension portion 62s of the outer lip 62l, the size of the sliding contact portion 62t, and the like, and is not particularly limited here. .

  Further, as in the configuration shown in FIG. 4, the base of the extension portion 62s is arranged on the outer peripheral surface of the outer lip 62l of the seal 60, that is, on the side opposite to the side where the sliding contact portion 62t is provided. A rib 62r may be provided to cover from the end 62u to the extending end 62v. Thereby, the strength (rigidity) against the force (reversing force) for reversing the outer lip 62l (the extending portion 62s and the sliding contact portion 62t) that acts on the extending portion 62s of the outer lip 62l during assembly work. ) And the outer lip 62l can be made to have a structure that can sufficiently resist the reversal force. The size, shape, and the like of the rib 62r are not particularly limited here because they may be arbitrarily set according to the extension length and material of the extension portion 62s of the outer lip 62l.

  Further, as shown in FIG. 5, from the end on the inboard side of the sliding contact surface 42d of the rotating wheel 42 to the portion where the sliding contact portion 62t of the outer lip 62l is positioned and is in sliding contact with the sliding contact surface 42d. The counter bore portion formed by dropping the groove shoulder portion on the inboard side of the raceway surface 42a formed on the rotating wheel 42 (specifically, the hub 10 (FIG. 6)) rather than the dimension (distance 5a shown in the figure). It is preferable to set the axial dimension of 42b (distance 5b shown in the figure) to be large (distance 5a <distance 5b).

  That is, by setting the distance 5a and the distance 5b to such a relationship (distance 5a <distance 5b), the sliding contact portion 62t of the outer lip 62l contacts the sliding contact surface 42d of the rotating wheel 42 when the assembling work is performed. Prior to this, the rolling element (ball) 44 of the assembly body mentioned above comes into contact with the counter bore portion 42b of the rotating wheel 42, and the stationary wheel 40 and the rotating wheel 42 (hub 10 (FIG. 6)) of the assembly body. Will be centered. As a result, in a state where the stationary wheel 40 and the rotating wheel 42 (hub 10) are centered, the outboard seal 46 is moved to a position where the sliding contact portion 62t is in sliding contact with the sliding contact surface 42d from a substantially vertical direction (radial direction). It can be moved and positioned. As a result, it is possible to effectively prevent the outer lip 621 (the extending portion 62s and the sliding contact portion 62t) of the seal 60 from being reversed in the assembling operation.

It is a figure which shows the structural example of the bearing unit for wheel support which concerns on one Embodiment of this invention, Comprising: (a) is principal part sectional drawing for demonstrating the sealing structure of the state which assembled | attached the outboard seal, (b) ) Is a cross-sectional view for explaining the configuration of the outboard seal. The figure for demonstrating the assembly work performed in the state which inserted the assembly jig | tool in the assembly clearance, and the said assembly jig. (a) is principal part sectional drawing which shows the structural example of the wheel support bearing unit which made the sliding contact surface the taper structure, (b) is principal part sectional drawing which shows the structural example of the sliding contact surface made into the stepped structure. . Sectional drawing which shows the structural example which provided the rib in the outer side lip of an outboard seal. The conceptual diagram for demonstrating the centering state of a stationary wheel and a rotary wheel at the time of an assembly | attachment operation | work. Sectional drawing which shows the example of whole structure of the bearing unit for wheel support. It is a figure for demonstrating the sealing structure of the conventional wheel support bearing unit, Comprising: (a) is principal part sectional drawing for demonstrating the state which assembled | attached the outboard seal, (b) is an outboard seal. Sectional drawing for demonstrating this structure, (c), (d) is principal part sectional drawing which shows the structural example for preventing the flooding to the sliding contact part of an outer side lip and a sliding contact surface.

Explanation of symbols

40 stationary wheel 42 rotating wheel 42c concave curved surface 42d sliding contact surface 42f hub flange 42i hub flange inner surface 42s peripheral surface 44 rolling element 46 sealing device (outboard seal)
50 cored bar 52 fixed portion 54 annular portion 54a base end portion 54b connecting portion 54c distal end portion 60 seal 60l (62l, 64l, 66l) lip 62s outer lip extending portion 62t outer lip sliding contact portion 62v outer lip extending end A1 Opposite distance B1 between outer lip extension end and hub flange inner surface B1 Projection height of outer lip sliding contact portion D1 Outer lip sliding diameter H1 Outboard seal press-fitting surface (core metal fixed portion-outer lip extension portion diameter difference)
X Bearing unit for wheel support

Claims (2)

A stationary wheel fixed to the vehicle body component member, a rotating wheel to which the wheel component member is fixed and rotating together with the wheel component member, and a double row raceway surface formed on the stationary wheel and the rotating wheel and facing each other. A wheel-supporting bearing unit comprising a plurality of rolling elements incorporated so as to be able to roll in between, and a sealing device interposed between the stationary wheel and the rotating wheel to keep the inside airtight and liquid-tight. And
The sealing device includes a cylindrical fixed part extending in a predetermined direction, and an annular cored bar continuously extending from an extended end on one side of the fixed part; And a seal provided with a plurality of lips formed to extend in sliding contact with the rotating wheel,
The seal includes an extended portion in which a lip that is in sliding contact with the rotating wheel on the outermost side extends in a cylindrical shape substantially parallel to the axial direction, and a portion inside the bearing from the extended end of the extended portion It is composed of a sliding contact portion that is continuously projected over the entire circumference of the inner peripheral surface of the part so as to reduce the inner diameter dimension of the part, and is fixed to the stationary wheel via the cored bar. In this state, the sliding contact portion is brought into sliding contact with the outer peripheral portion of the rotating wheel while the extending end of the extending portion is opposed to the outer peripheral portion of the rotating wheel at a predetermined interval with respect to the radial direction . The extension end of the extension portion protrudes toward the wheel component member side from the end surface of the stationary wheel on the wheel component member side, and the extension end is the outer periphery of the rotating wheel. It is positioned so as to face the part with a predetermined interval with respect to the axial direction,
When the distance between the extension end of the extension part and the outer peripheral part of the rotating wheel in the axial direction is A1, and the protrusion height of the sliding contact part is B1, the relation of A1 <B1 is set. A wheel support bearing unit characterized by the above. When the stationary wheel, the cage, and the rolling element are assembled to the rotating wheel, two assembly jigs that form a substantially semi-annular shape are attached to an end surface of the stationary wheel on the wheel component member side and the rotating wheel. The seal lip that is slidably contacted on the outermost side with the rotating wheel is positioned and assembled in a state where the extension portion is guided by the assembly jig and the extension portion is guided by these assembly jigs. The wheel support bearing unit according to claim 1, wherein the assembly jig is removed from the gap after the work is completed .

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