JP6607305B2 - Wheel support bearing unit - Google Patents

Description

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

  Various wheel support bearing units equipped with a rotation sensor have been proposed in order to measure the rotational speed of automobile wheels. For example, in the case of a wheel support bearing unit that supports a driven wheel, it is known that a rotation sensor is provided on the inner side of the bearing unit that is the inner side of the vehicle body, and the inner side end of the inner ring that is a rotating wheel is provided. While the encoder is fixed, a sensor holder (cover member) holding a sensor is disposed at the inner side end of the outer ring which is a stationary ring.

As a sensor holder, a sensor holder is known in which a resin portion is molded into a bottomed cylindrical shape on an annular metal core. When molding the resin part on the core metal, the core metal and the resin part do not adhere to each other due to molding shrinkage of the resin material, and the butted surface (butting surface) of the inner side end surface of the outer ring and the outer side surface of the resin part of the sensor holder The sealing performance in the mating region) may be lowered.
If the sealing performance of the abutting surface is lowered in this manner, foreign matter such as muddy water enters from the abutting area, and there is a possibility that the muddy water may reach the inside of the bearing through the surface of the core metal. .

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

  However, when the axial surface portion 101 rusts due to moisture that has entered the butting region 300 radially outward (external space side) from the O-ring 400, and an axial gap is generated in the butting region 300, the O-ring is generated from this gap. 400 plasticizers of rubber material may flow out. Furthermore, since the O-ring 400 is used in a state where three sides are covered with an O-ring groove 500 provided in the resin portion, the plasticizer of the rubber material of the O-ring 400 may move to the resin portion. . In such a case, the rubber elasticity of the O-ring 400 is lost and hardened, and the sealing performance may be reduced. In addition, if a resin part material is selected that has water resistance and salt carbonate resistance and does not absorb the rubber plasticizer, the resin part material is limited, resulting in high costs. It was.

JP 2008-256512 A

  The present invention has been made in view of the above-described problems of the prior art, and the problem is that the sealing performance by the O-ring disposed in the abutting region between the inner side end of the outer ring and the cover member is improved. It is an object of the present invention to provide a wheel-supporting bearing unit that is maintained for a long period of time and prevents foreign matters such as muddy water from entering the inside of the bearing.

In order to achieve the above-described problems, a wheel support bearing unit according to the present invention includes an outer ring having an outer ring raceway on an inner peripheral surface, and an inner ring having an inner ring raceway and a flange for supporting the wheel on an outer peripheral 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 an inner side end of the outer ring,
The cover member is composed of an annular cored bar that fits to an inner side end of the outer ring, and a resin part that is molded integrally with the cored bar. An outer diameter side of the inner ring side end of the outer ring is formed with a cover protruding in the outer side, and an inner diameter surface of the flange has a tapered surface that increases in diameter toward the outer side. A small-diameter step portion is formed, an outer diameter surface of the small-diameter step portion is an outer ring radial direction surface portion, and an inner side 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 shafts. Abutting area is formed by abutting in the direction, and an O-ring is interposed in the abutting area, and the cored bar is fitted and fixed to the inner diameter surface of the outer ring located on the outer side of the abutting area And provided 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 configured to protrude and overlap in a bowl shape on the outer diameter side of the step portion. Therefore, the inner side end surface of the outer ring and the cover member It is possible to prevent muddy water from being directly applied to the abutting 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 abutting region between the inner side end portion of the outer ring and the cover member is maintained for a long period of time, and foreign matters such as water and mud enter the bearing. It is possible to provide a wheel-supporting bearing unit that can effectively prevent this.

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

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Each embodiment is merely an embodiment of the present invention, and is not construed as being limited thereto. The design can be changed within the scope of the present invention. In addition, 3rd Embodiment and 4th Embodiment are the scope of the present invention, 1st Embodiment has shown the premise description, 2nd Embodiment is a reference example.

[First embodiment]
FIG. 1 shows a first embodiment of the present invention. The wheel support bearing unit of the present embodiment includes an outer ring 1 having a double-row outer ring raceway 7 on the inner peripheral surface, and an outer peripheral surface having a mounting flange 5 that is fixed to a suspension device (not shown) of an automobile. The inner ring 19 having a double-row inner ring raceway 21 on the outer peripheral surface, and a plurality of rolling elements incorporated between each outer ring raceway 7 and each inner ring raceway 21 (see FIG. Ball) 29, an encoder 33 fixed to the inner side end of the inner ring 19, a sensor holder 43 that is a cover member that is fitted and fixed to the inner side end of the outer ring 1 and seals the bearing inner space, and a sensor holder And a sensor 39 fixed to the 43 sensor holes 59. In addition, the arrow X in a figure has shown the axial direction, and the right side of each figure is defined as an inner side and the left side is defined as an outer side. An arrow Y indicates the radial direction.

  The outer ring 1 is made of medium carbon steel, and a recess 11 is formed by denting the radially inner portion of the inner side end toward the outer side. The inner diameter surface of the recessed portion 11 that is the outer ring radial direction surface portion 13 is formed into a tapered surface that increases in diameter toward the inner side. The inner side surface of the recessed portion 11 is a plane orthogonal to the axis 17 and is formed in an annular shape, 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 is formed with a diameter smaller than the radial width of the recessed portion 11 and with a thickness larger than the axial width of the recessed portion 11, and partly from the recessed portion 11 toward the inner side. It is arranged in a protruding state.
The entire sensor holder 43 is formed of a cored bar 45 and a resin portion 53 in a bottomed cylindrical shape. The cored bar 45 is formed by pressing a metal plate, and has a cylindrical cored bar cylindrical part 47 and an annular shape formed continuously from the inner side end of the cored bar cylindrical part 47 to the outer diameter side. The core metal ring part 49 is constituted. The resin portion 53 includes a cylindrical resin cylindrical portion 55 and a disk-shaped resin bottom plate portion 57 formed continuously from the inner side end of the resin cylindrical portion 55 to the inner diameter side. The resin portion 53 is formed integrally with a core metal ring portion 49 of the core metal 45 and a portion of the core metal cylindrical portion 47 while covering the entire inner diameter surface of the core metal cylindrical portion 47.

  The outer side portion of the outer diameter surface of the cored bar cylindrical portion 47 is not covered with the resin portion 53, and the fitting surface 3 of the outer ring 1 formed continuously from the inner diameter edge of the recessed portion 11 toward the outer side. The sensor holder 43 is fixed to the outer ring 1 by directly fitting and fixing the outer side outer diameter surface of the cored bar portion 47. Then, the sensor holder 43 is positioned in the axial direction with respect to the outer ring 1 by an abutment region 65 in which the outer side end surface of the resin cylindrical portion 55 is abutted against the inner side surface of the recessed portion 11 in the axial direction.

  A circumferential groove 61 that is recessed toward the inner side is formed on the inner diameter side portion of the butting region 65 on the outer side end face of the resin cylindrical portion 55 constituting the sensor holder 43 over the entire circumference. The circumferential groove 61 is formed in a rectangular cross section that opens toward the outer side. The outer side surface and the outer side surface are formed by the resin portion 53, and the inner diameter side surface is formed by the cored bar cylindrical portion 47. Yes. 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 sealing performance of the sensor holder 43 with respect to the outer ring 1 is ensured.

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

  The sensor holder 43 is press-fitted into the recessed portion 11 formed at the inner side end of the outer ring 1, and the outer side end surface of the resin portion 53 in the sensor holder 43 is butted against the inner side surface of the recessed portion 11 (a butted region 65 is formed). When the cored bar cylindrical portion 47 is fitted and fixed to the fitting portion 3 of the outer ring 1 located on the outer side of the butting region 65, the outer ring radial surface portion 13 of the recessed portion 11 becomes the cover diameter of the sensor holder 43. On the outer diameter side of the directional surface portion 63, they are arranged so as to overlap with a predetermined radial clearance. For this reason, muddy water or the like is not directly applied to the abutting region 65 between the outer ring 1 and the sensor holder 43.

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

  Furthermore, the sealing property of the O-ring 67 disposed in the butt region 65 can be maintained for a long time. That is, since the rust is generated by the ingress of moisture and the axial gap is prevented from being generated in the butting region 65, the plasticizer of the rubber material of the O-ring 67 does not flow out to the outside. Furthermore, the O-ring 67 mounted in the circumferential groove 61 is used in a state where only two sides are covered with the resin portion 53 and the remaining two sides are covered with a metal material (the outer ring 1 and the cored bar 45). , The plasticizer of the O-ring 67 is suppressed from moving to the resin portion. Accordingly, it is possible to prevent the rubber elasticity of the O-ring 67 from being lost and becoming hard and the sealing performance from being lowered. In addition, since there is no limitation on the compatible material by using an O-ring, 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 description of the first embodiment will be used for other configurations and effects.

In the present embodiment, the outer ring radial surface portion 13 of the recessed portion 11 is a cylindrical surface having a constant inner diameter with respect to the axial direction, and a predetermined distance is provided between the cover radial direction surface portion 63 of the resin portion 53 and the outer ring radial surface portion 13. A dome-shaped protrusion (annular protrusion) 69 is formed over the entire circumference in a cross-sectional view having a tightening allowance.
According to the present embodiment, the same effect as the first embodiment is exhibited, and the tip portion of the ridge 69 has a tightening margin on the outer ring radial surface portion 13 located on the outer diameter side of the ridge 69. Since the contact is made over the entire circumference in the state, it is possible to prevent muddy water from entering the butt area 65.

In the present embodiment, the dome-shaped protrusion 67 is formed in a cross-sectional view, but is not limited to the protruding shape, and is formed with a predetermined allowance with the outer ring radial surface portion 13. If it is, the design can be changed as appropriate, such as a triangular shape or a polygonal shape in cross-sectional view. In addition, although this embodiment demonstrated with the form currently formed in series in the circumferential direction, the form formed in the axial direction by 2 series and 3 series may be sufficient, and a seal area | region is made by using multiple series. It is within the scope of the present invention to increase the sealing performance by increasing the number.
Moreover, in this embodiment, even if it is the structure which forms the outer ring radial direction surface part 13 in the taper surface which becomes large diameter as it goes to an inner side, it is applicable.

[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 description of the first embodiment will be used for other configurations and operational effects.

  In the present embodiment, a small-diameter step portion 71 is formed at the inner end of the outer ring 1, and the flange portion 77 of the sensor holder 43 is overlapped with a predetermined radial gap on the outer-diameter side of the small-diameter step portion 71. Embodiment which arrange | positions so that it may match is employ | adopted.

The small diameter step portion 71 is formed to have a smaller diameter than the outer diameter surface of the outer ring 1 on the entire outer diameter surface of the inner side end of the outer ring 1. A drainage groove 75 that is recessed toward the inner diameter side is provided all week of the outer side portion of the small-diameter stepped portion 71, and the outer side portion of the groove bottom of the drainage groove 75 has a taper that decreases in diameter toward the inner side. It is formed on the surface.
The inner side portion of the small-diameter stepped portion 71 is the outer ring radial direction surface portion 13 in the present embodiment, and is formed in a tapered surface that becomes smaller in diameter toward the outer side.

The sensor holder 43 is provided with an annular flange 77 projecting in the axial direction toward the outer side on the outer diameter surface of the resin portion 53. The inner diameter surface of the collar portion 77 is the cover radial direction surface portion 63 in the present embodiment, and is formed in a tapered surface having a larger diameter toward the outer side.
In addition, the circumferential groove 61 that accommodates the O-ring 67 is constituted by the cored bar 45 on both the inner diameter surface and the outer side surface, 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 side end portion of the outer ring 1, the inner side end surface of the outer ring 1 having a smaller diameter than the small diameter step portion 71 (outer ring radial direction surface portion 13) and the resin cylinder of the sensor holder 43. The outer side end face of the portion 55 abuts in the axial direction to form the abutment region 65 in the present embodiment, and the flange portion 77 is located on the outer diameter side of the small diameter step portion 71. Therefore, the cover radial direction surface portion 63 of the flange portion 77 is positioned on the outer diameter side of the butting region 65 so as to overlap 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 so as to extend slightly beyond the outer ring radial surface portion 13 of the small diameter step portion 71 toward the outer side and to a position overlapping the drain groove 75 in the radial direction.

According to the present embodiment, the outer ring radial surface portion 13 and the cover radial direction surface portion 63 are positioned on the outer diameter side of the butting region 65 so as to overlap each other in the radial direction. It is possible to do so.
The outer diameter surface (outer ring radial direction surface portion 13) of the small diameter step portion 71 is a tapered surface having a smaller diameter toward the outer side, and the inner diameter surface (cover radial direction surface portion 63) of the flange portion 77 is directed toward the outer side. Since the tapered surface has a large diameter, even if muddy water enters the small diameter step portion 71, the muddy water can be quickly drained from the small diameter step portion 71 (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 a metal material (the outer ring 1 and the cored bar 45). The plasticizer of the ring 67 is further suppressed from moving to the resin portion, thereby preventing the sealing performance from being lowered.
In addition, since the thickness in the radial direction of the resin cylindrical portion 55 can be increased compared to the first and second embodiments described above, the resin moldability is improved and the strength of the sensor holder 43 is increased. . Therefore, the sensor holder 43 can be prevented from being damaged when the resin cylindrical portion 55 is pushed to press-fit the sensor holder 43 to the fitting surface 3 of the outer ring 1.

[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, a labyrinth seal is formed by increasing the amount of protrusion (extension amount) in the axial direction of the flange portion 77 and extending to the vicinity of the step surface 73 of the step portion 71 as compared to the third embodiment described above. In addition, the small-diameter step portion 71 is not provided with a drain groove.
Further, by bending the outer side portion of the cored bar cylindrical portion 47 to the inner diameter side, the fitting force to the fitting surface 3 is enhanced while facilitating press-fitting.

Since both the outer ring 1 and the sensor holder 43 are stationary members, a very narrow labyrinth gap can be set, and foreign matter such as muddy water can be prevented from being directly applied to the butting region 65.
In addition, when the labyrinth gap is narrow and the drainage performance of muddy water is poor, a drain hole (not shown) can be provided in the lower portion in the vertical direction of the flange portion 77 of the sensor holder 43.
In addition, since the axial thickness of the resin cylindrical portion 55 is thicker than that of 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 having a resin end cap as a cover member. The present invention can also be applied to other wheel support bearing units than those shown in this specification.

DESCRIPTION OF SYMBOLS 1 Outer ring 3 Fitting part 5 Fixed flange 7 Outer ring raceway 11 Recessed part 13 Outer ring radial surface part 19 Inner ring 20 Rotating flange 21 Inner ring raceway 29 Rolling element 33 Encoder 39 Sensor 43 Sensor holder 45 Core metal 47 Core metal cylindrical part 49 Core metal circle Ring portion 53 Resin portion 55 Resin cylindrical portion 57 Resin bottom plate portion 59 Sensor hole 61 Circumferential groove 63 Cover radial direction surface portion 65 Abutting area 67 O-ring 69 Projection 71 Small diameter step portion 73 Step portion 75 Drainage groove 77 ridge portion

Claims (3)

An outer ring having an outer ring raceway on the inner peripheral surface;
An inner ring having an inner ring raceway and a flange for supporting the wheel on the outer peripheral surface;
A plurality of rolling elements incorporated between the outer ring raceway and the inner ring raceway;
A wheel support bearing unit comprising a cover member fitted to an inner side end of the outer ring,
The cover member is composed of an annular cored bar that fits to an inner side end of the outer ring, and a resin part that is molded integrally with the cored bar. Forming a flange that protrudes toward the outer side, and the inner diameter surface of the flange is a cover radial surface portion having a tapered surface that increases in diameter toward the outer side;
Forming a small diameter step on the outer diameter side of the inner side end of the outer ring, the outer diameter surface of the small diameter step is an outer ring radial surface portion;
An inner side 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 abutted in the axial direction to form a butt region, and an O-ring is interposed in the butt region. And
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 direction surface portion provided at the inner side end of the outer ring and the cover member The wheel support bearing unit, wherein the cover radial surface portion provided is positioned in a state of overlapping 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 an outer side of the small diameter step portion of the outer ring.   2. The wheel support bearing unit according to claim 1, wherein the small-diameter step portion of the outer ring is a tapered surface having a maximum outer diameter on the inner side end surface and a smaller diameter toward the outer side.

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