JP2019049360A - Bearing unit for supporting wheel - Google Patents

Abstract

To provide a bearing unit which maintains sealability by an O ring disposed in a butted area between an inner side end part of an outer ring and a cover member to effectively prevent entry of foreign objects, such as water and slurry, into a bearing.SOLUTION: A bearing unit for supporting a wheel includes: an outer ring 1 connected to the vehicle body side; a hub ring 19 which is disposed so as to rotate relatively to the outer ring 1; rolling elements 29 incorporated between the outer ring 1 and the hub ring 19; and a cover member 43 which is fitted in an inner side end part of the outer ring 1 to make a seal. The bearing unit has a butted area 65 where the inner side end surface of the outer ring 1 and an outer side surface of the cover member 43 are butted in an axial direction. A small diameter step part 71 of the inner side end part of the outer ring 1 and an eaves part 77 of the cover member 43 are located so as to overlap with each other in a radial direction at the outer diameter side of the butted area 65.SELECTED DRAWING: Figure 3

Description

  The present invention relates to, for example, a bearing unit for supporting a wheel, which rotatably supports a wheel of an automobile with respect to a suspension device and has a resin cover member such as a sensor holder or an end cap disposed at an end of an outer ring.

  In order to measure the rotation speed of the wheel of a car, various bearing units for wheel support provided with a rotation sensor have been proposed. For example, in the case of a wheel supporting bearing unit for supporting a driven wheel, it is known that a rotation sensor is provided on the inner side of the bearing unit which is the inner side of the vehicle body. While the encoder is fixed, a sensor holder (cover member) holding a sensor is disposed at an inner end of an outer ring which is a stationary wheel.

As the sensor holder, one configured by molding a resin portion in a cylindrical shape with a bottom on an annular core metal is known. When molding the resin part on the metal core, the core metal and the resin part are not in close contact due to the effect of molding shrinkage of the resin material, and the butt surface of the inner end face of the outer ring and the outer side face of the resin part of the sensor holder The sealing performance in the mating area may be low.
If the sealability of the butt surfaces is lowered in this way, foreign matter such as muddy water may infiltrate from the butt region, and muddy water may reach the inside of the bearing along the surface of the metal core. .

  In order to improve the sealing performance between the inner end of the outer ring and the sensor holder, as illustrated in FIG. 5, in the axial surface portion 101 of the inner end of the outer ring 100 and the resin portion of the sensor holder 200 An O-ring 400 is disposed in the butting region 300 with the axial surface portion 201 on the outer side, and waterproofing is performed by the O-ring 400 (to improve sealing performance) (see Patent Document 1).

  However, when the axial surface portion 101 is rusted by moisture invading the butt region 300 radially outward (external space side) of the O ring 400 and an axial gap is generated in the butt region 300, the O ring Plasticizer of 400 rubber materials may flow out. Furthermore, since the O-ring 400 is used with the O-ring groove 500 provided in the resin portion covered in three directions, the plasticizer of the rubber material of the O-ring 400 may be transferred to the resin portion. . In such a case, the rubber elasticity of the O-ring 400 is lost and the O-ring 400 becomes hard, which may reduce the sealing performance. In addition, if the material of the resin portion is selected so as to have water resistance and salt resistance and does not cause absorption of the rubber plasticizer, the material of the resin portion is limited, and as a result, the cost increases. The

JP 2008-256512 A

  The present invention has been made in view of the above-mentioned problems of the prior art, and the place to be solved is the sealing property by the O-ring disposed in the butt region of the inner end of the outer ring and the cover member. An object of the present invention is to provide a wheel support bearing unit which is maintained for a long period of time to prevent the entry of foreign matter such as muddy water into the interior of the bearing.

In order to achieve the problems as described above, the bearing unit for supporting a wheel according to the present invention is an inner ring having an outer ring having an outer ring raceway on an inner circumferential surface and a flange for supporting an inner ring raceway and a wheel on an outer circumferential surface. A wheel support bearing unit comprising: a plurality of rolling elements incorporated between the outer ring raceway and the inner ring raceway; and a cover member fitted to the inner end of the outer ring.
The cover member is configured of an annular core metal fitted to the inner end of the outer ring, and a resin portion integrally formed with the core, and the outer diameter end of the resin portion An outer diameter side of the cover is formed with a flange portion projecting to the outer side, and the inner diameter surface of the flange portion has a tapered surface having a larger diameter toward the outer side, and the outer diameter side of the inner end portion of the outer ring The small diameter step portion is formed, the outer diameter surface of the small diameter step portion is the outer ring radial direction surface portion, and the inner side end surface of the outer ring and the outer side surface of the resin portion located on the inner diameter side of the flange portion The core metal is fixedly fitted on the inner diameter surface of the outer ring which is butted in a direction to form a butting area, and an O-ring is interposed in the butting area, and is located on the outer side of the butting area. And at the inner end of the outer ring The cover radial surface portion provided on the cover member and the outer ring radially face which has been characterized in that position while overlapping in the radial direction at the outer diameter side of the butt area.

  According to the present invention, the step portion is provided on the outer diameter side of the outer ring, and the cover radial direction surface portion is formed to overlap and overlap in a bowl shape on the outer diameter side of the step portion. It is possible to prevent muddy water from being caught directly on the butt region of the resin portion with the outer side surface.

  According to the present invention, the sealing performance of the O-ring disposed in the butt region between the inner end of the outer ring and the cover member is maintained for a long time, and foreign matter such as water and mud infiltrates into the bearing. It is possible to provide a wheel support bearing unit that can effectively prevent the

BRIEF DESCRIPTION OF THE DRAWINGS (a) schematic sectional drawing which shows 1st Embodiment, (b) partial expanded sectional view. The (a) schematic sectional view, (b) partial expanded sectional view which shows 2nd Embodiment. (A) schematic sectional drawing which shows 3rd Embodiment, (b) partial expanded sectional view. (A) schematic sectional drawing which shows 4th Embodiment, (b) partial expanded sectional view. BRIEF DESCRIPTION OF THE DRAWINGS FIG.

  Hereinafter, each embodiment of the present invention will be described based on the drawings. Each embodiment is only one embodiment of the present invention and is not construed as limiting in any way, and design changes can be made within the scope of the present invention. The third embodiment and the fourth embodiment are the scope of the present invention, the first embodiment shows the premise thereof, and the second embodiment is a reference example.

First Embodiment
FIG. 1 shows a first embodiment of the present invention. The wheel support bearing unit according to the present embodiment includes an outer ring 1 having a plurality of outer ring raceways 7 on its inner circumferential surface, and an outer circumferential surface provided with a mounting flange 5 fixed to a suspension system (not shown) of a vehicle. And an inner ring 19 having a plurality of inner ring raceways 21 on the outer peripheral surface thereof, and a plurality of rolling elements incorporated between each outer ring raceway 7 and each inner ring raceway 21 A ball 29), an encoder 33 fixed to the inner end of the inner ring 19, a sensor holder 43 as a cover member which is fitted and fixed to the inner end of the outer ring 1 and seals the space in the bearing; And a sensor 39 fixed to the 43 sensor holes 59. The arrow X in the drawings indicates the axial direction, and the right side of each drawing is defined as the inner side, and the left side is defined as the outer side. The arrow Y indicates the radial direction.

  The outer ring 1 is made of medium carbon steel, and a recessed portion 11 is formed by recessing the radially inner portion of the inner end portion toward the outer side. The inner diameter surface of the recessed portion 11 which is the outer ring radial direction surface portion 13 is formed as a tapered surface which increases in diameter toward the inner side. The inner side surface of the recessed portion 11 is formed in an annular shape at a plane orthogonal to the axial center 17 and is formed continuously with the outer side end portion of the outer ring radial direction surface portion 13.

The sensor holder 43, which is a cover member, has a diameter smaller than the radial width of the recess 11, and is thicker than the axial width of the recess 11. A portion of the sensor holder 43 extends from the recess 11 toward the inner side. It is disposed in a protruding state.
The sensor holder 43 is entirely configured in a cylindrical shape with a bottom by the core metal 45 and the resin portion 53. The metal core 45 is formed by pressing a metal plate, and has an annular shape formed continuously from the inner end portion of the cylindrical metal core cylindrical portion 47 and the core metal cylindrical portion 47 to the outer diameter side. And a core metal ring portion 49 of FIG. The resin portion 53 is constituted by a cylindrical resin cylindrical portion 55 and a disk-shaped resin bottom plate portion 57 formed continuously from the inner end portion of the resin cylindrical portion 55 to the inner diameter side. The resin portion 53 is integrally molded by a configuration in which the core metal ring portion 49 of the core metal 45 and a part of the core metal cylindrical portion 47 are embedded and the entire inner diameter surface of the core metal cylindrical portion 47 is covered.

  The outer side portion of the outer diameter surface of the metal core cylindrical portion 47 is not covered by the resin portion 53, and the fitting surface 3 of the outer ring 1 continuously formed from the inner diameter edge of the recessed portion 11 toward the outer side. In addition, the sensor holder 43 is fixed to the outer ring 1 by directly fitting and fixing the outer side outer diameter surface of the metal core cylinder 47. Then, the butt region 65 in which the outer end surface of the resin cylindrical portion 55 is axially abutted against the inner side surface of the recessed portion 11 positions the sensor holder 43 in the axial direction with respect to the outer ring 1.

  A circumferential groove 61 recessed toward the inner side is formed over the entire circumference on the inner diameter side portion of the butting region 65 at the outer side end surface of the resin cylindrical portion 55 that constitutes the sensor holder 43. The circumferential groove 61 is formed in a rectangular shape in cross section that opens toward the outer side, and the outer diameter side surface and the outer side surface are constituted by the resin portion 53 and the inner diameter side surface is constituted by the metal core cylindrical portion 47. There is. In a state where the sensor holder 43 is fixed to the outer ring 1, an O-ring 67 is attached to the circumferential groove 61, and the O-ring is held between the inner side surface of the recessed portion 11 and the outer side surface of the circumferential groove 61. Thus, the sealability of the sensor holder 43 with respect to the outer ring 1 is secured.

A sensor hole 59 is recessed in the resin bottom plate portion 57 of the sensor holder 43 in a state where it is opened to the inner side surface of the resin bottom plate portion 57 and the outer side surface is closed. A sensor 39 is internally mounted in the sensor hole 59, and the sensor 39 axially faces the encoder 33 via the bottom of the sensor hole 59.
Further, the outer diameter surface of the resin portion 53 (the resin cylindrical portion 55) which is the cover radial direction surface portion 63 is formed as a tapered surface which becomes smaller in diameter toward the inner side.

  The sensor holder 43 is pressed into the recess 11 formed at the inner end of the outer ring 1, and the outer end surface of the resin portion 53 in the sensor holder 43 is butted to the inner side surface of the recess 11 (a butting area 65 is formed) ), And the core metal cylindrical portion 47 is fixedly fitted to the fitting portion 3 of the outer ring 1 positioned on the outer side of the butting region 65, the outer ring radial direction surface portion 13 of the recessed portion 11 has a cover diameter of the sensor holder 43. It is disposed on the outer diameter side of the direction surface portion 63 so as to overlap in a state in which a predetermined radial gap is opened. For this reason, muddy water or the like does not directly contact the butting region 65 of the outer ring 1 and the sensor holder 43.

  Further, since the outer ring radial direction surface portion 13 of the recessed portion 11 is a tapered surface whose diameter increases toward the inner side, and the cover radial direction surface portion 63 of the sensor holder 43 is a tapered surface whose diameter decreases toward the inner side. Even if muddy water intrudes into the vicinity of the butt region 65, the muddy water is quickly discharged to the outside along the outer ring radial direction surface portion 13 or the cover radial direction surface portion 63 of the recessed portion 11.

  Furthermore, the sealability of the O-ring 67 disposed in the butt region 65 can be maintained for a long time. That is, since the occurrence of rust due to the entry of water and the generation of an axial gap in the butt region 65 is prevented, the plasticizer of the rubber material of the O-ring 67 does not flow out. Furthermore, the O-ring 67 mounted in the circumferential groove 61 is used in a state in which only two sides are covered with the resin portion 53 and the other two sides are covered with the metal material (the outer ring 1 and the core metal 45) The plasticizer of the O-ring 67 is suppressed from migrating to the resin portion. Therefore, it is possible to prevent the rubber elasticity of the O-ring 67 from being lost and becoming hard, and the sealing performance being lowered. Moreover, since the limitation of the compatible material by the use of the O-ring can also be eliminated, the material cost does not increase.

Second Embodiment
FIG. 2 shows a second embodiment of the present invention. In the present embodiment, only the differences from the first embodiment will be described, and the descriptions of the first embodiment will be incorporated for other configurations and effects.

In the present embodiment, the outer ring radial direction surface portion 13 of the recessed portion 11 is a cylindrical surface whose inner diameter is constant in the axial direction, and the distance between the outer ring radial direction surface portion 13 and the cover radial direction surface portion 63 of the resin portion 53 is predetermined. A dome-like protrusion (annular protrusion) 69 is formed over the entire circumference in a cross-sectional view with an interference of.
According to the present embodiment, the same effects as those of the first embodiment are exhibited, and the tip portion of the protrusion 69 has an interference in the outer ring radial direction surface portion 13 located on the outer diameter side of the protrusion 69 Since contact is made over the entire circumference in the state, it is possible to prevent muddy water infiltration into the butting area 65.

In the present embodiment, the dome-shaped protrusion 67 is formed in a cross-sectional view, but it is not limited to the protruding shape and is formed with a predetermined interference with the outer ring radial direction surface portion 13 As long as it is made, it is possible to appropriately change the design, such as a triangular shape or a polygonal shape in a cross sectional view. In the present embodiment, the circumferential direction is described as being formed in series, but it may be formed in two or three in the axial direction, and the sealing area may be formed by forming a plurality of series. It is also within the scope of the present invention to improve the sealability in many cases.
Further, in the present embodiment, the outer ring radial direction surface portion 13 may be formed into a tapered surface which increases in diameter toward the inner side.

Third Embodiment
FIG. 3 shows a third embodiment of the present invention. In the present embodiment, only the differences from the first and second embodiments will be described, and the descriptions of the first embodiment will be incorporated in other configurations and operational effects.

  In the present embodiment, the small diameter step portion 71 is formed at the inner side end portion of the outer ring 1, and the flange portion 77 of the sensor holder 43 is overlapped on the outer diameter side of the small diameter step portion 71 with a predetermined radial gap. The embodiment arranged to match is adopted.

The small diameter step portion 71 is formed on the entire outer diameter surface of the inner end portion of the outer ring 1 so as to be smaller in diameter than the outer diameter surface of the outer ring 1. A drainage groove 75 recessed toward the inner diameter side is provided all week of the outer side portion of the small diameter step portion 71, and the outer side portion of the groove bottom of the drainage groove 75 has a tapered shape with a smaller diameter toward the inner side. It is formed on the surface.
The inner side portion of the small diameter step portion 71 is the outer ring radial direction surface portion 13 in the present embodiment, and is formed as a tapered surface whose diameter decreases toward the outer side.

The sensor holder 43 is provided on the outer diameter surface of the resin portion 53 with an annular collar portion 77 that protrudes in the axial direction toward the outer side. The inner diameter surface of the collar portion 77 is the cover radial direction surface portion 63 in the present embodiment, and is formed as a tapered surface having a large diameter toward the outer side.
Further, in the circumferential groove 61 for housing the O-ring 67, two sides of the inner diameter surface and the outer side surface are constituted by the core metal 45, and only the outer diameter surface is constituted by the resin portion 53.

In a state where the sensor holder 43 is fitted to the inner end of the outer ring 1, the inner end face of the outer ring 1 having a diameter smaller than that of the small diameter step 71 (the outer ring radial surface 13) and the resin cylinder of the sensor holder 43 The outer end surface of the portion 55 abuts in the axial direction to constitute the butting region 65 in the present embodiment, and the collar portion 77 is positioned outside the small diameter step portion 71. Therefore, on the outer diameter side of the butting region 65, the cover radial direction surface portion 63 of the collar portion 77 is overlapped with the outer ring radial direction surface portion 13 of the small diameter step portion 71 with a predetermined radial clearance. doing.
The flange portion 77 is formed to extend slightly to the outer side on the outer ring radial direction surface portion 13 of the small diameter step portion 71 to a position overlapping the drainage groove 75 in the radial direction.

According to the present embodiment, the outer ring radial direction surface portion 13 and the cover radial direction surface portion 63 are positioned so as to overlap in the radial direction on the outer diameter side of the butt region 65, so muddy water is not directly applied to the butt region 65 It is possible to do so.
Further, the outer diameter surface (outer ring radial direction surface portion 13) of the small diameter step portion 71 is a tapered surface which decreases in diameter toward the outer side, and the inner diameter surface (cover radial direction surface portion 63) of the collar portion 77 faces the outer side. Since the tapered surface has a large diameter, even if the muddy water enters into the small diameter step portion 71, the muddy water can be drained quickly from the small diameter step portion 71 (the drainage groove 75).

The O-ring 67 mounted in the circumferential groove 61 is used in a state where only one side is covered with the resin portion 53 and the remaining three sides are covered with the metal material (the outer ring 1 and the core metal 45). The transfer of the plasticizer of the ring 67 to the resin portion is further suppressed to prevent the sealing performance from decreasing.
Further, since the radial thickness of the resin cylindrical portion 55 can be formed to be thicker than in the first and second embodiments described above, the moldability of the resin is improved and the strength of the sensor holder 43 is increased. . Therefore, when the resin cylindrical portion 55 is pressed to press fit the sensor holder 43 to the fitting surface 3 of the outer ring 1, the sensor holder 43 can be prevented from being damaged.

Fourth Embodiment
FIG. 4 shows a fourth embodiment of the present invention. In the present embodiment, only the differences from the first to third embodiments will be described, and the description of the first embodiment will be used for other configurations and operational effects.

In the present embodiment, the labyrinth seal is formed by extending the protrusion amount in the axial direction (the protrusion amount) of the collar portion 77 to the vicinity of the step surface 73 of the step portion 71 with respect to the third embodiment described above. And the small diameter step portion 71 is not provided with a drainage groove.
Further, by bending the outer side portion of the metal core cylindrical portion 47 to the inner diameter side, the fitting force with respect to the fitting surface 3 is strengthened while facilitating press-fitting.

Since both the outer ring 1 and the sensor holder 43 are stationary members, it is possible to set a very narrow labyrinth gap, and it is possible to prevent foreign matter such as muddy water from being directly applied to the butt region 65.
When the labyrinth gap is narrow and drainage of muddy water is poor, it is also possible to provide a drain hole (not shown) at the lower part in the vertical direction of the ridge portion 77 of the sensor holder 43.
Further, since the axial thickness of the resin cylindrical portion 55 is increased as compared with the third embodiment, the strength of the sensor holder 43 is further increased to prevent the sensor holder 43 from being damaged.

  The present invention is applicable to a wheel support bearing unit provided with a resin end cap as a cover member. The present invention is also applicable to other forms of wheel support bearing units than those described herein.

DESCRIPTION OF SYMBOLS 1 outer ring 3 fitting portion 5 fixed flange 7 outer ring raceway 11 recessed portion 13 outer ring radial direction surface 19 inner ring 20 rotating flange 21 inner ring track 29 rolling element 33 encoder 39 sensor 43 sensor holder 45 core metal 47 core metal cylindrical portion 49 core metal circle Ring portion 53 Resin portion 55 Resin cylindrical portion 57 Resin bottom plate portion 59 Sensor hole 61 Peripheral groove 63 Cover radial direction surface portion 65 Butt region 67 O ring 69 Protrusion 71 Small diameter step portion 73 Step portion 75 Drain groove 77 Collar

Claims (3)

An outer ring having an outer ring raceway on an inner circumferential surface;
An inner ring having an inner ring raceway and a flange for supporting the wheel on an outer peripheral surface;
A plurality of rolling elements incorporated between the outer ring raceway and the inner ring raceway;
And a cover member fitted to the inner end of the outer ring.
The cover member is configured of an annular core metal fitted to the inner end of the outer ring, and a resin portion integrally formed with the core, and the outer diameter end of the resin portion A flange portion projecting toward the outer side is formed, and an inner diameter surface of the flange portion is a cover radial direction surface portion having a tapered surface which becomes larger in diameter toward the outer side,
A small diameter step portion is formed on the outer diameter side of the inner side end portion of the outer ring, and an outer diameter surface of the small diameter step portion is an outer ring radial direction surface portion,
An inner end surface of the outer ring and an outer side surface of the resin portion located on the inner diameter side of the flange portion are axially butted to form a butting region, and an O ring is interposed in the butting region. Yes,
The core metal is fitted and fixed to the inner diameter surface of the outer ring located on the outer side of the butting region, and the outer ring radial surface portion and the cover member provided at the inner end portion of the outer ring A bearing unit for wheel support characterized in that the provided cover radial direction surface portions are positioned so as to overlap in the radial direction on the outer diameter side of the butting region.   The wheel support bearing unit according to claim 1, wherein a groove is formed on the outer side of the small diameter step portion of the outer ring.   The wheel support bearing unit according to claim 1, wherein the small diameter step portion of the outer ring is a tapered surface whose end surface on the inner side is a maximum outer diameter and whose diameter decreases toward the outer side.

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