JP2020106043A - Wheel bearing device - Google Patents

Abstract

To provide a suitable wheel bearing device which is improved in the discharge performance of muddy water or the like intruding therein.SOLUTION: In a wheel bearing device 1 which comprises: an inner member having an outer ring 2, a hub ring 3, and at least one inner ring 4 pressure-inserted into the hub ring 3; double-row rolling bodies 5, 6 rollingly accommodated between both raceway surfaces of the outer ring 2 and the inner member; and a sensor cap 12 fit to an external peripheral face of a pilot part 2g of the outer ring 2, an internal peripheral face 2j of the pilot part 2g is formed into a tapered shape expanding toward an inner side in a radial direction, the sensor cap 12 has a water drain hole 12d adjoining the inner side with respect to a fitting part 12e fit to the external peripheral face of the pilot part 2g, and an inner-side end face 2k of the pilot part 2g is flush with a boundary face 12f with respect to the fitting part 12e out of an internal peripheral face of the water drain hole 12d.SELECTED DRAWING: Figure 2

Description

The present invention relates to a wheel bearing device.

BACKGROUND ART A wheel bearing device that rotatably supports a wheel is known. In the wheel bearing device, a hub wheel, which is an inner member connected to the wheel, is rotatably supported via rolling elements. The wheel bearing device is provided with a seal member that prevents grease from leaking through the gap between the outer member and the inner member and prevents muddy water or the like from entering from the outside.

The wheel bearing device may be provided with a rotation speed detection device that detects the rotation speed of the wheel. Specifically, in the wheel bearing device, a magnetic encoder and a rotation speed sensor that detects a magnetic pole change of the magnetic encoder are provided. Here, the rotation speed sensor is attached to the wheel bearing device while being inserted into the sensor cap. For example, it is as described in Patent Document 1. In the bearing device for a wheel described in Patent Document 1, a drain (drain hole) protruding in the axial direction is formed at the bottom portion (side surface in the axial direction) of the sensor cap in order to discharge foreign matter such as muddy water. ..

JP, 2015-175407, A

However, in the wheel bearing device described in Patent Document 1, the inner peripheral surface of the pilot portion of the outer member and the inner peripheral surface of the sensor cap are formed parallel to the central axis, so that they have entered the inside. A part of muddy water may stay on the inner peripheral surface of the pilot portion or the inner peripheral surface of the sensor cap. The accumulated muddy water may accelerate the corrosion of the outer member or the sensor cap. In addition, when the accumulated mud water evaporates, the residue accumulates on the inner peripheral surface of the pilot portion or the inner peripheral surface of the sensor cap and sticks to it, which may hinder the drain discharge function.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a suitable wheel bearing device that improves the dischargeability of muddy water and the like that have entered the inside.

That is, the first aspect of the present invention includes a pilot portion fitted to a knuckle of a vehicle body, an outer member having a double row outer raceway surface formed on the inner circumference, and a small-diameter step portion extending axially on the outer circumference surface. A double row having a formed hub wheel and at least one inner ring press-fitted into a small-diameter step portion of the hub wheel, and on the outer peripheral surfaces of the hub wheel and the inner ring facing the outer raceway surface of the double row. An inner member having an inner raceway surface formed therein, a double row rolling element accommodated between both raceway surfaces of the outer member and the inner member so as to be rollable, and an inner side of the inner member. An encoder ring which is provided at an end portion and whose magnetism alternately changes at equal intervals in the circumferential direction, a bottomed cylindrical sensor cap fitted to the outer peripheral surface of the pilot portion, and a magnetic sensor provided on the sensor cap. In the bearing device for a wheel, the inner peripheral surface of the pilot portion is formed in a taper shape that spreads radially outward toward the inner side, and the sensor cap is fitted to the outer peripheral surface of the pilot portion. A fitting portion and a drainage hole adjacent to the fitting portion on the inner side, and a boundary surface between the fitting portion and the inner peripheral surface of the drainage hole is the pilot portion. Is a bearing device for a wheel that is positioned flush with the inner side end surface of or on the inner side with respect to the inner side end surface.

The effects of the present invention are as follows.

That is, according to the first aspect of the invention, since the inner peripheral surface of the pilot portion is formed as an inclined surface that descends toward the inner side end, muddy water or the like collected on the bottom portion along the inner peripheral surface of the pilot portion is Flows down to the drain hole adjacent to the inner end surface of the. As a result, muddy water, rainwater, or the like that has entered the inside of the wheel bearing device can be guided to the water drain hole of the sensor cap and discharged without being retained in the pilot portion.

Sectional drawing which shows the whole structure of the bearing device for wheels. The partial expanded sectional view of the pilot part periphery of the bearing device for wheels. FIG. 3 shows the flow of muddy water in the pilot section. (A) is a sectional view perpendicular to the axial direction showing the flow of muddy water or the like in the circumferential direction of the pilot section, and (B) is a partially enlarged sectional view parallel to the axial direction showing the flow of muddy water or the like in the axial direction.

Hereinafter, a wheel bearing device 1 which is an embodiment of a wheel bearing device according to the invention will be described with reference to FIG. 1.

As shown in FIG. 1, a wheel bearing device 1 rotatably supports a wheel in a suspension device of a vehicle such as an automobile. The wheel bearing device 1 includes an outer ring 2 that is an outer member, a hub wheel 3 and an inner ring 4 that are inner members, two inner row ball rows 5 that are rolling rows, outer row ball rows 6, and inner seals. A member 9, an outer seal member 10, a sensor cap 12 and a magnetic sensor 14 are provided. Here, the inner side refers to the vehicle body side of the wheel bearing device 1 when attached to the vehicle body, and the outer side refers to the wheel side of the wheel bearing device 1 when attached to the vehicle body. The axial direction means the direction along the rotation axis of the wheel bearing device 1.

An inner opening 2a into which the inner seal member 9 can be fitted is formed at the inner end of the outer ring 2. An outer opening 2b into which the outer seal member 10 can be fitted is formed at the outer end of the outer ring 2. An inner side outer raceway surface 2c and an outer side outer raceway surface 2d are formed on the inner peripheral surface of the outer ring 2. A vehicle body mounting flange 2e for mounting to the knuckle 100 on the vehicle body side is integrally formed on the outer peripheral surface of the outer ring 2. The vehicle body mounting flange 2e is formed at a position overlapping the inner opening 2a when viewed in the radial direction. A plurality of bolt holes 2f are formed in the vehicle body mounting flange 2e.

A cylindrical pilot portion 2g that fits into the knuckle 100 is formed on the inner side of the vehicle body mounting flange 2e. A knuckle fitting surface 2h into which the knuckle 100 is fitted and a sensor cap fitting surface 2i into which the sensor cap 12 is fitted are formed on the outer periphery of the pilot portion 2g. The knuckle fitting surface 2h is formed on the outer side (the vehicle body mounting flange 2e side) of the pilot portion 2g. The sensor cap fitting surface 2i is formed on the inner side of the pilot portion 2g with an outer diameter smaller than that of the knuckle fitting surface 2h. The inner circumference of the pilot portion 2g is formed to have an inner diameter larger than that of the inner opening 2a.

At the inner end of the hub wheel 3, a small-diameter step portion 3a having a diameter smaller than that of the outer end is formed on the outer peripheral surface. A wheel mounting flange 3b for mounting a wheel is integrally formed on the outer end of the hub wheel 3. The wheel mounting flange 3b is provided with a plurality of hub bolts 3e at circumferentially equidistant positions. Further, the hub wheel 3 is provided with an outer side inner raceway surface 3c that faces the outer side outer raceway surface 2d of the outer ring 2. An inner ring 4 is provided on the small-diameter step portion 3 a of the hub wheel 3.

The inner ring 4 is a rolling row and applies a preload to the inner ball row 5 arranged on the vehicle body side when mounted on the vehicle and the outer ball row 6 arranged on the wheel side when mounted on the vehicle. An inner raceway surface 4a is formed on the outer peripheral surface of the inner ring 4. The inner ring 4 is fixed to the small-diameter step portion 3a of the hub wheel 3 by press fitting and caulking. That is, the inner race 4 constitutes the inner raceway surface 4 a on the inner side of the hub wheel 3. The inner raceway surface 4a of the inner ring 4 faces the outer raceway surface 2c on the inner side of the outer ring 2.

In the inner side ball row 5 and the outer side ball row 6 which are rolling rows, a plurality of balls 8 which are rolling elements are annularly held by a cage 7. The inner ball row 5 is rotatably sandwiched between the inner raceway surface 4a of the inner race 4 and the outer raceway surface 2c of the outer race 2 on the inner side. The outer ball row 6 is rotatably sandwiched between the inner raceway surface 3c of the hub wheel 3 and the outer raceway surface 2d of the outer race 2 on the outer side.

The wheel bearing device 1 is composed of a double row angular contact ball bearing including an outer ring 2, a hub ring 3 and an inner ring 4, an inner side ball row 5, and an outer side ball row 6. In the present embodiment, the wheel bearing device 1 is not limited to the double row angular contact ball bearing, and may be formed of the double row tapered roller bearing.

The inner seal member 9, which is a sealing member, is a pack seal that closes the gap between the inner opening 2 a of the outer ring 2 and the inner ring 4. The inner seal member 9 is composed of, for example, a two-side lip type pack seal that brings two seal lips into contact with each other.

The outer seal member 10, which is a sealing member, is a seal member that mainly closes the gap between the outer ring 2 and the hub ring 3. The outer side seal member 10 has a cylindrical portion fitted to the outer side fitting portion of the outer ring 2, and a plurality of seal lips come into contact with or come close to the lip sliding surface 3d of the hub ring 3 through an oil film, so that the outer ring 2 Muddy water or foreign matter is prevented from entering through the gap between the hub wheel 3 and the hub wheel 3.

The encoder ring 11 (thin black portion) is a part of a rotation speed detection device that detects the rotation speeds of the hub wheel 3 and the inner ring 4 that are members on the rotation side. The encoder ring 11 is made of synthetic rubber in which a magnetic powder such as ferrite is mixed and formed in an annular shape, and the magnetic poles N and S are magnetized at equal pitches in the circumferential direction. The encoder ring 11 is supported on the outer diameter surface of the inner ring 4 via a metal support ring 13. The encoder ring 11 is integrally joined to the bent portion of the support ring formed in a cylindrical shape by vulcanization adhesion. The other end of the support ring is press-fitted into the inner ring 4 from the outer end.

The sensor cap 12 is a cap that holds the magnetic sensor 14 in the inner side opening 2a of the outer ring 2 and seals the opening of the pilot portion 2g of the outer ring 2. The sensor cap 12 has a bottomed cylindrical shape. The sensor cap 12 has a cylindrical cylindrical portion 12a and a disk-shaped bottom portion 12b. The cylindrical portion 12a is formed with an inner diameter smaller than the outer diameter of the sensor cap fitting surface 2i of the pilot portion 2g. That is, the cylindrical portion 12a has a fitting portion 12e having an inner diameter and an axial length that can be press fitted into the sensor cap fitting surface 2i. An attachment portion 12c to which the magnetic sensor 14 is attached is formed on the bottom portion 12b.

The sensor cap 12 is fitted to the sensor cap fitting surface 2i of the pilot portion 2g. That is, the sensor cap 12 is fitted to the pilot portion 2g of the outer ring 2 so as to cover the inner seal member 9. As a result, the sensor cap 12 holds the magnetic sensor 14 attached to the bottom portion 12b thereof at an appropriate position with respect to the encoder ring 11, and closes the opening of the pilot portion 2g.

The magnetic sensor 14 detects the passage time of each magnetism of the encoder ring 11 that rotates integrally with the hub wheel 3 and alternately passes through the detection surface. Thus, the wheel bearing device 1 includes the rotation speed detection device including the encoder ring 11 and the magnetic sensor 14. In addition, in the present embodiment, the rotation speed detection device may have a configuration other than using a detected portion other than the encoder ring 11.

Next, the pilot portion 2g of the outer ring 2 and the sensor cap 12 will be specifically described with reference to FIGS. 2 and 3.

As shown in FIG. 2, the inner peripheral surface 2j of the pilot portion 2g has an inner diameter larger at the inner end than at the outer end. Further, the inner diameter of the outer side end portion is larger than the inner diameter of the inner side opening portion 2a. That is, the inner peripheral surface 2j of the pilot portion 2g is formed in a taper shape with a gradient α that spreads radially outward from the outer side (inner side opening 2a side) toward the inner side. Therefore, when the wheel bearing device 1 is attached to the knuckle 100 (see FIG. 1), the bottom portion of the inner peripheral surface 2j of the pilot portion 2g on the road surface G (see FIG. 3) side faces the inner side. It becomes an inclined surface. Further, the inner peripheral surface 2j of the pilot portion 2g is also an inclined surface inclined toward the bottom portion on the road surface G side. The taper gradient α of the inner peripheral surface 2j is preferably 2% or more, which is considered to flow water.

A water drain hole 12d is formed in the cylindrical portion 12a. Specifically, the water drainage hole 12d is arranged at a position adjacent to the fitting portion 12e in the cylindrical portion 12a. The drain hole 12d is arranged on the inner side with respect to the fitting portion 12e. When the sensor cap 12 is fitted to the outer ring 2, the drain hole 12d is formed at a position adjacent to the inner end surface (axial end surface) 2k of the pilot portion 2g. A boundary surface 12f of the inner peripheral surface of the drain hole 12d with the fitting portion 12e is flush with the inner end surface 2k of the pilot portion 2g. Further, when the wheel bearing device 1 is attached to the knuckle 100, the sensor cap 12 is attached to the outer ring 2 in a direction in which the drain hole 12d is arranged at a position (bottom portion) closest to the road surface G of the cylindrical portion 12a. It is fitted. The inner peripheral surface of the cylindrical portion 12a is arranged radially outside the inner peripheral surface 2j of the pilot portion 2g. That is, the drain hole 12d is arranged in a state of being vertically oriented on the road surface G side of the inner peripheral surface 2j of the pilot portion 2g.

As shown in FIG. 3, when muddy water enters the vicinity of the inner seal member 9, the wheel bearing device 1 uses muddy water or the like on the road surface G side by the inclined surface in the inner circumferential surface 2j of the pilot portion 2g in the circumferential direction. To the bottom (see the black arrow in FIG. 3(A)). Further, the wheel bearing device 1 guides the muddy water or the like guided to the bottom portion of the pilot portion 2g to the inner side end of the pilot portion 2g by the inclined surface extending in the axial direction (see the black arrow in FIG. 3(B)). ). The muddy water or the like, which is guided to the inner end of the pilot portion 2g and collected, is dropped into the water drain hole 12d of the sensor cap 12 adjacent to the inner end surface 2k of the pilot portion 2g and discharged to the outside. In particular, the muddy water guided along the inner peripheral surface 2j of the pilot portion 2f is further guided through the step (inner side end surface 2k) with respect to the water drain hole 12d, and is therefore easily discharged to the outside. In addition, the drainage hole 12d according to the present embodiment has the boundary surface 12f with the fitting portion 12e flush with the inner side end surface 2k, so that the muddy water guided through the pilot portion 2g is discharged to the outside early. can do.

The position of the boundary surface 12f with the fitting portion 12e on the inner peripheral surface of the drainage hole 12d is not limited to being flush with the inner end surface 2k of the pilot portion 2g, but may be on the inner side with respect to the inner end surface 2k. It may be located.

A wheel bearing device 1 according to the present application includes a hub wheel 3 into which an inner ring 4 is fitted as an inner member, and an outer ring 2 serving as an outer member, an inner ring 4 serving as an inner member, and a fitted body of the hub wheel 3. Although the third-generation structure of the inner ring rotating specification is configured as described above, the first-generation structure including the outer ring 2 that is the outer member and the pair of inner rings 4 that is the inner member, and the outer ring 2 that is the outer member. And a pair of inner rings 4 that are inner members, and the pair of inner rings 4 may be a second-generation structure of an inner ring rotation specification in which the pair of inner rings 4 are fitted to the outer periphery of the hub wheel 3. Further, the wheel bearing device 1 has been described as a wheel bearing device for a driven wheel, but may be a wheel bearing device for a drive wheel.

Although the embodiments of the present invention have been described above, the present invention is not limited to these embodiments at all and is merely an example, and further various modifications may be made without departing from the scope of the present invention. It is needless to say that the scope of the present invention is shown by the description of the claims, and further, the equivalent meanings described in the claims and all modifications within the scope are Including.

1 Wheel Bearing Device 2 Outer Ring 2c, 2d Outer Raceway Surface 2g Pilot Part 2j Inner Circumferential Surface 2k Inner Side End Surface 3 Hub Ring 4 Inner Ring 5 Inner Side Ball Row 6 Outer Side Ball Row 12 Sensor Cap 12d Drain Hole 12e Fitting Part 12f boundary surface

Claims (2)

A pilot portion fitted to the knuckle of the vehicle body, and an outer member having a double row outer raceway surface formed on the inner periphery,
A hub wheel having a small-diameter step portion extending in the axial direction on the outer peripheral surface, and at least one inner ring press-fitted into the small-diameter step portion of the hub wheel, wherein the outer peripheral surface of the hub wheel and the inner ring has the An inner member having a double row inner raceway surface facing the double row outer raceway surface,
A double row rolling element housed between the raceways of the outer member and the inner member so as to be rollable,
An encoder ring, which is provided at the inner end of the inner member and in which magnetism alternately changes at equal intervals in the circumferential direction,
A cylindrical sensor cap with a bottom fitted to the outer peripheral surface of the pilot portion,
In a wheel bearing device including a magnetic sensor provided in the sensor cap,
The inner peripheral surface of the pilot portion is formed in a tapered shape that spreads radially outward toward the inner side,
The sensor cap has a fitting portion fitted to the outer peripheral surface of the pilot portion, and a drain hole adjacent to the fitting portion on the inner side,
A bearing device for a wheel, wherein a boundary surface between the fitting portion and an inner peripheral surface of the water drain hole is flush with an inner end surface of the pilot portion or on an inner side with respect to the inner end surface. The wheel bearing device according to claim 1, wherein the boundary surface is flush with the inner end surface of the pilot portion.

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