JP2019052738A - Hub unit bearing - Google Patents

Abstract

[Problem] To realize a structure that can prevent foreign matter such as muddy water from entering an annular gap that exists between the inner peripheral surface of an encoder, the outer peripheral surface of an inner ring, and the axial outer end face of a sensor cover. [Solution] An encoder lip portion 46 that extends radially inward is provided on the inner peripheral edge of an encoder 20a of an encoder-attached combination seal ring 17a that closes the axial inner end opening of an internal space 16a of a hub unit bearing 1a. The tip edge of the encoder lip portion 46 is brought into contact with the outer peripheral surface of the axial outer end of a fitting cylindrical portion 26a that constitutes a sensor cover 25a with a tightening margin. [Selected Figure] Figure 2

Description

  The present invention relates to a hub unit bearing used for rotatably supporting a wheel with respect to a suspension device.

  An automobile wheel and a braking rotator are supported by a hub unit bearing so as to be rotatable with respect to the suspension device. In addition, in order to control a vehicle behavior control device such as an anti-lock brake system (ABS), the rotation speed of a wheel is also detected using a hub unit bearing. FIG. 4 shows an example of a conventional structure of a hub unit bearing described in Japanese Patent Application Laid-Open No. 2011-117475.

  The hub unit bearing 1 is a hub unit bearing for a driving wheel used in combination with a constant velocity joint, and an inner member (hub) 3 and a plurality of rolling elements 4 are provided on the inner diameter side of the outer member 2. It is comprised by supporting through rotation freely.

  The outer member 2 is provided with a double row outer ring raceway 5 on the inner peripheral surface, and a stationary flange 7 for supporting and fixing to the knuckle 6 on the outer peripheral surface. The inner member 3 is provided with a double row inner ring raceway 8 and a rotating flange 9 for supporting and fixing the wheel on the outer peripheral surface, and a spline hole 10 is provided on the inner peripheral surface. Such an inner member 3 includes a hub ring 11 and an inner ring 12 that is externally fitted to the hub ring 11. A spline shaft 14 fixed to the constant velocity joint outer ring 13 is inserted into the spline hole 10, and a nut 15 is screwed into a tip portion of the spline shaft 14.

Openings at both ends in the axial direction of the internal space 16 existing between the outer member 2 and the inner member 3 are seal rings to prevent entry of foreign matter such as muddy water and leakage of lubricant such as grease. It is blocked. In the hub unit bearing 1 having a conventional structure, the axially inner end opening of the internal space 16 is closed by the combined seal ring 17 with an encoder in order to detect the rotational speed of the wheel.
Note that “inside” in the axial direction refers to the right side of FIGS. 1 to 5, which is the center side in the width direction of the vehicle when the hub unit bearing is assembled to the suspension device. On the contrary, the left side of FIGS. 1 to 5, which is the outer side in the width direction of the vehicle in a state where the hub unit bearing is assembled to the suspension device, is referred to as “outside” in the axial direction.

  As shown in FIG. 5, the combined seal ring 17 with an encoder includes a seal ring 18 and a slinger 19 that constitute the combined seal ring, and an encoder 20.

  The seal ring 18 is fitted and fixed to the inner end of the outer member 2 in the axial direction, and includes a cored bar 21 and a sealing material 22 made of an elastic material fixed to the cored bar 21. The seal material 22 is provided with a plurality of seal lips 23a to 23c. The slinger 19 has an L-shaped cross section and is formed in an annular shape as a whole, and is externally fitted and fixed to the outer peripheral surface of the inner ring 12 constituting the inner member 3. The encoder 20 is made of a permanent magnet, has a ring shape as a whole, and is supported by a slinger 19. S poles and N poles are alternately arranged at equal intervals in the circumferential direction on the inner side surface in the axial direction, which is the detected surface of the encoder 20.

  The detection portion 24a of the sensor 24 supported by the knuckle 6 is opposed to the detection surface of the encoder 20 in close proximity. When the encoder 20 rotates together with the inner member 3, the south pole and the north pole existing on the detection surface of the encoder 20 pass in the vicinity of the detection unit 24a of the sensor 24, and the output signal of the sensor 24 is set to the rotational speed of the wheel. Change accordingly. For this reason, it becomes possible to detect the rotational speed of the wheel from the output signal of the sensor 24.

  A sensor cover 25 is fixed to the inner ring 12 in order to protect the detection part 24a of the sensor 24 from stepping stones and muddy water. The sensor cover 25 has a substantially L-shaped cross section and is formed in an annular shape as a whole. The sensor cover 25 is bent so as to be bent radially outward from the axially inner end of the fitting cylinder 26 and the fitting cylinder 26. Part 27. The outer end portion in the axial direction of the fitting tube portion 26 is formed in a cylindrical shape, whereas the inner end portion or the intermediate portion in the axial direction of the fitting tube portion 26 has an outer diameter dimension as it goes inward in the axial direction. It is configured in the shape of a conical cylinder that increases. The axially outer end portion of the fitting cylinder portion 26 is externally fitted to the cover fitting surface 29 on the outer peripheral surface of the inner ring 12. The cover fitting surface 29 has a smaller diameter than the slinger fitting surface 28 to which the slinger 19 is fitted and fixed, and is located on the inner side in the axial direction on the outer peripheral surface of the inner ring 12. Further, the outer peripheral edge in the axial direction of the fitting cylinder portion 26 is made to enter the inner diameter side of the encoder 20, and the labyrinth seal 30 is formed between the outer peripheral surface of the fitting cylinder portion 26 and the inner peripheral surface of the encoder 20. ing. This prevents foreign matter such as muddy water from entering the annular gap 32 existing between the inner peripheral surface of the encoder 20, the outer peripheral surface of the inner ring 12, and the axially outer end surface of the fitting cylinder portion 26. Yes.

JP 2011-117475 A

  However, in the conventional structure described above, once foreign matter such as muddy water enters the annular gap 32, the foreign matter is hardly discharged from the annular gap 32 due to the presence of the labyrinth seal 30. For this reason, when foreign matters stay in the annular gap 32 for a long period of time, rust is generated in the inner ring 12 and the sensor cover 25, and there is a possibility that alkaline rust juice is generated.

  Here, the phenol resin adhesive widely used for fixing the encoder 20 to the slinger 19 or vulcanizing and bonding rubber to the core has a property of low alkali resistance. . For this reason, when alkaline rust juice stays in the annular gap 32, a part of the encoder 20 is peeled off from the slinger 19, leading to a decrease in detection accuracy of the sensor 24, or the encoder 20 falling off the slinger 19. There is a possibility that the rotation speed cannot be detected by the sensor 24 itself.

  The present invention has been made in view of the circumstances as described above, and its purpose is in an annular gap existing between the inner peripheral surface of the encoder, the outer peripheral surface of the inner ring, and the axial outer end surface of the sensor cover. The object is to realize a structure that can effectively prevent the intrusion of foreign matter such as muddy water.

The hub unit bearing of the present invention includes an outer member, an inner member, a plurality of rolling elements, a combined seal ring with an encoder, and a sensor cover.
The outer member has a double-row outer ring raceway on the inner peripheral surface, and is supported and fixed to the suspension device during use, and does not rotate.
The inner member is formed by coupling and fixing a hub wheel and an inner ring. The inner member has a double-row inner ring raceway on an outer peripheral surface, and a wheel is fixed during use and rotates together with the wheel.
Each of the rolling elements is provided between the outer ring raceway and the inner ring raceway so as to roll freely.
The combined seal ring with an encoder closes an axially inner end opening of an internal space existing between an inner peripheral surface of the outer member and an outer peripheral surface of the inner member, and is fixed to the outer member. A sealing ring, a slinger externally fixed to the inner ring, and an annular encoder supported by the slinger.
The sensor cover protects a sensor disposed opposite to the inner side surface in the axial direction of the encoder, and includes a fitting cylinder portion that is fitted and fixed to the inner ring, and an inner end portion in the axial direction of the fitting cylinder portion. And a bent portion that is bent outward in the radial direction.
Furthermore, in the hub unit bearing of the present invention, a slinger fitting surface on which the slinger is fitted and fixed to the outer peripheral surface of the inner ring, and a smaller diameter than the slinger fitting surface and provided on the inner side in the axial direction. And a cover fitting surface on which the fitting tube portion is fitted and fixed, and a step portion connecting the cover fitting surface and the slinger fitting surface.
An encoder lip portion is provided on the inner peripheral edge of the encoder over the entire circumference. The encoder lip portion is offset to the outside in the axial direction from the portion facing the detection portion of the sensor, on the inner side surface in the axial direction of the encoder, and the tip edge of the encoder lip portion is set to the inner diameter of the slinger. It is made to contact the outer peripheral surface of the axial direction outer end part of the said fitting cylinder part whose outer diameter is smaller than.

  In the present invention, the sensor cover can be made of a plated steel plate that has been plated with a base metal (for example, zinc) that has a higher ionization tendency than the steel plate that is the base material.

  According to the hub unit bearing of the present invention as described above, foreign matter such as muddy water enters the annular gap existing between the inner peripheral surface of the encoder, the outer peripheral surface of the inner ring, and the axial outer end surface of the sensor cover. Can be effectively prevented.

FIG. 1 is a cross-sectional view showing a hub unit bearing, showing a first example of an embodiment of the present invention. FIG. 2 is an enlarged view of a portion X in FIG. FIG. 3 is a diagram corresponding to FIG. 2 regarding the second example of the embodiment. FIG. 4 is a cross-sectional view showing a conventional hub unit bearing. FIG. 5 is a view corresponding to FIG. 2 with respect to FIG. 4 having a conventional structure.

[First example of embodiment]
A first example of the embodiment will be described with reference to FIGS. The hub unit bearing 1a of this example is a hub unit bearing for a driving wheel used in combination with a constant velocity joint, and includes an outer member 2a that is a stationary wheel, an inner member 3a that is a rotating wheel, Rolling elements 4.

  The outer member 2a is made of a hard metal such as medium carbon steel, and includes a double row outer ring raceway 5a and a stationary flange 7a for supporting and fixing the outer member 2a to the suspension device. Each of the double-row outer ring raceways 5a has a circular arc cross section and is formed on the inner peripheral surface of the outer member 2a. The stationary flange 7a is provided at the axially intermediate portion of the outer member 2a so as to protrude radially outward. Mounting holes 33 are provided at a plurality of locations in the circumferential direction of the radial intermediate portion of the stationary flange 7a. The outer member 2 a is supported and fixed to the knuckle 6 constituting the suspension device by a coupling member 34 such as a bolt screwed or inserted into the mounting hole 33.

  The inner member 3a is disposed coaxially with the outer member 2a on the inner diameter side of the outer member 2a, and rotates to support the double-row inner ring raceway 8a, the driving wheel, and the braking rotator. And a flange 9a. Each of the double-row inner ring raceways 8a has an arc shape in cross section, and is provided on a portion of the outer peripheral surface of the inner member 3a facing the double-row outer ring raceway 5a. The rotating flange 9a is provided on the outer side in the axial direction of the inner member 3a. Coupling holes 35 are provided at a plurality of locations in the circumferential direction on the radially outer side of the rotating flange 9a. The wheel and the brake rotating body are supported on the rotating flange 9a by a stud 36 press-fitted into the coupling hole 35 or a screwed bolt.

The inner member 3a is configured by coupling and fixing the hub ring 11a and the inner ring 12a, and is rotatably supported via the rolling element 4 on the inner diameter side of the outer member 2a.
The hub wheel 11a is made of a hard metal such as medium carbon steel, and has a rotating flange 9a extending radially outward at a portion protruding axially outward from the axially outer end of the outer member 2a. have. Further, the hub wheel 11a has an inner ring raceway 8a in an axially outer row at an axially intermediate portion of the outer peripheral surface, and has a small-diameter step portion 37 at a portion closer to the inner end in the axial direction of the outer peripheral surface. A spline hole 10a is provided on the inner peripheral surface (center portion) of the hub wheel 11a.

  The inner ring 12a is made of a hard metal such as bearing steel that has not been subjected to rust prevention treatment, and the whole is configured in an annular shape. As shown in FIG. 2, on the outer peripheral surface of the inner ring 12a, the inner ring raceway 8a in the axially inner row, the slinger fitting surface 28a, the step portion 31, and the cover fit from the axially intermediate portion to the inner end portion. A surface 29a is provided. Such an inner ring 12a is externally fitted to a small-diameter stepped portion 37 of the hub wheel 11a, and an axial inner end surface is suppressed by a caulking portion 38 formed at an axial inner end portion of the hub wheel 11a.

The inner ring raceway 8a in the inner row in the axial direction has a circular arc cross section and is formed on the outer peripheral surface in the axial direction intermediate portion of the inner ring 12a. The slinger fitting surface 28a has a cylindrical surface and is provided on the shoulder portion of the inner ring 12a adjacent to the inner side in the axial direction of the inner ring raceway 8a in the inner row in the axial direction. The cover fitting surface 29a has a cylindrical surface, is formed on the outer peripheral surface of the inner end portion in the axial direction of the inner ring 12a, and has a smaller diameter than the slinger fitting surface 28a. Sensor In this example, the 1/2 of the difference between the outer diameter _{D 29} of the outer diameter _{D 28} and the cover fitting surface 29a of the slinger fitting surface _{28a {(D 28 -D 29)} / 2}, later are the same _{{(D 28 -D 29) /} 2 = T} and the thickness T of the metal plate for use in making the cover 25a. The step portion 31 is a composite surface configured by combining a plurality of surfaces whose outer diameters change in the axial direction, and exists between the slinger fitting surface 28a and the cover fitting surface 29a, and these slinger fitting surfaces. 28a and the cover fitting surface 29a are connected. Specifically, the step portion 31 is provided adjacent to the inner side in the axial direction of the slinger fitting surface 28a, and a first inclined surface portion whose outer diameter decreases linearly toward the inner side in the axial direction, and the first inclined surface A second inclined surface portion having an inclination angle larger than that of the first inclined surface portion, and a concave curved surface portion smoothly connecting the second inclined surface portion and the cover fitting surface 29a, which are provided adjacent to the inner side in the axial direction of the surface portion. It is composed of

  A spline shaft 14a fixed to the outer end surface in the axial direction of the constant velocity joint outer ring 13a is inserted into the spline hole 10a provided on the inner peripheral surface of the hub wheel 11a (spline engagement). A nut 15a is screwed onto the tip of the spline shaft 14a. As a result, the constant velocity joint and the hub wheel 11a are coupled so as to be able to transmit torque, and the hub wheel 11a is prevented from coming off from the spline shaft 14a in the axial direction. Further, the axial outer end surface of the constant velocity joint outer ring 13 a is abutted against the axial inner side surface of the caulking portion 38.

  The rolling elements 4 are made of hard metal such as bearing steel or ceramic, and a plurality of rolling elements 4 can be freely rolled between each row between the outer ring raceway 5a and the inner row raceway 8a. Has been placed. In the illustrated example, balls are used as the rolling elements 4, but tapered rollers can also be used.

  Of the cylindrical inner space 16a existing between the inner peripheral surface of the outer member 2a and the outer peripheral surface of the inner member 3a, the axially outer end opening is closed by the seal ring 39, and the axial direction The inner end opening is closed by a combined seal ring 17a with an encoder. This prevents foreign matters such as muddy water from entering the internal space 16a and prevents the lubricant such as grease enclosed in the internal space 16a from leaking to the outside.

  The seal ring 39 includes a cored bar 40 made of a metal plate such as a cold rolled steel plate (SPCC), and a sealing material 41 made of an elastic material such as an elastomer fixed to the cored bar 40 by an adhesive means such as vulcanization adhesion. It is composed of The core metal 40 is fitted and fixed to the outer end of the outer member 2a in the axial direction by an interference fit. In this state, the leading edges of the plurality of seal lips provided on the seal material 41 are connected to the rotary flange 9a. Are respectively slidably contacted with each other along the inner circumferential surface and the outer circumferential surface of the intermediate portion in the axial direction of the hub wheel 11a.

  As shown in FIG. 2, the combined seal ring 17a with an encoder includes a seal ring 18a and a slinger 19a that constitute a combined seal ring, and an encoder 20a that constitutes a rotational speed detection device together with a sensor 24 described later.

  The seal ring 18a is fitted and fixed to the inner end portion in the axial direction of the outer member 2a, and includes a cored bar 21a and a sealing material 22a fixed to the cored bar 21a.

  The cored bar 21a is formed by pressing a metal plate such as a cold rolled steel plate, has an L-shaped cross section, and is configured in an annular shape as a whole. The cored bar 21a is a cylindrical fixed cylindrical portion 42 that is fitted and fixed to the inner end in the axial direction of the outer member 2a, and is bent radially inward from the outer end in the axial direction of the fixed cylindrical portion 42. An annular ring-shaped fixed ring portion 43 is provided.

  The sealing material 22a is made of an elastic material such as acrylonitrile butadiene rubber (NBR), and is fixed to the surface of the core metal 21a over the entire circumference by an adhesive means such as vulcanization adhesion. Specifically, the sealing material 22a covers the inner peripheral surface of the fixed cylindrical portion 42 and the inner end portion in the axial direction of the fixed cylindrical portion 42 over the entire circumference, and the axial inner side surface of the fixed annular portion 43 and the fixed circular ring. The radially inner end of the portion 43 is covered over the entire circumference. The sealing material 22a is provided with a plurality of (three in the illustrated example) sealing lips 23d to 23f. Of the seal lips 23d to 23f, the seal lip 23d disposed on the outermost radial direction is an axial lip (side lip) extending inward in the axial direction, and the remaining two seal lips 23e and 23f are in the radial direction. A radial lip extending inward. 2 and FIG. 3 to be described later show the shapes of the seal lips 23d to 23f and the encoder lip portion 46 to be described later in a free state.

  The slinger 19a is formed by pressing a metal plate such as a ferritic stainless steel plate such as SUS430 or a cold-rolled steel plate that has been subjected to rust prevention treatment, and has an L-shaped cross section and is configured in an annular shape as a whole. The slinger 19a is externally fitted and fixed to a slinger fitting surface 28a formed on the shoulder of the inner ring 12a. The slinger 19a includes a cylindrical rotating cylindrical portion 44 that is fitted and fixed to the slinger fitting surface 28a by an interference fit, and a circle that is bent at a right angle from the axially inner end of the rotating cylindrical portion 44 toward the radially outer side. And a ring-shaped rotating annular portion 45. In a state where the rotating cylindrical portion 44 constituting the slinger 19a is externally fitted and fixed to the slinger fitting surface 28a, the rotating annular portion 45 has a step portion 31 (first inclined surface portion) constituting the outer peripheral surface of the inner ring 12a. Is located radially outward. Further, the outer peripheral surface of the rotating cylindrical portion 44 and the axially outer surface of the rotating annular ring portion 45 are respectively smooth surfaces. Of the seal lips 23 d to 23 f, the tip edge of the seal lip 23 d arranged on the outermost side in the radial direction is brought into sliding contact with the axially outer side surface of the rotating ring portion 45. Further, the leading edges of the remaining two seal lips 23 e and 23 f are slidably contacted or closely opposed to the outer peripheral surface of the rotating cylindrical portion 44.

  The encoder 20a is made of a permanent magnet such as a rubber magnet or a plastic magnet, and is configured in a ring shape as a whole. A phenol resin rubber adhesive is formed on the inner surface in the axial direction of the rotating ring portion 45 constituting the slinger 19a. Is fixed by adhesion. The encoder 20a is located radially outward of the step portion 31 that forms the outer peripheral surface of the inner ring 12a. The encoder 20a is magnetized in the axial direction, and the magnetization direction changes alternately and at equal intervals in the circumferential direction. For this reason, S poles and N poles are alternately arranged at equal intervals in the circumferential direction on the detection surface of the encoder 20a.

An encoder lip 46 that extends radially inward is provided on the inner peripheral edge of the encoder 20a over the entire circumference. The encoder lip 46 has a triangular cross section or a trapezoidal cross section, and its axial width decreases toward the tip side. Further, the encoder lip portion 46 has a dimension H on the axially outer side of the inner side surface in the axial direction of the encoder 20a and the portion facing the detection portion 24a of the sensor 24 (detected surface, radial intermediate portion). It is provided with an offset (in a retracted state). For this reason, the annular recessed part 47 is provided in the radial direction inner end part of the axial direction inner surface of the encoder 20a. The inner diameter dimension of the encoder lip portion 46 in the free state is smaller than the inner diameter dimension of the rotating cylindrical portion 44 constituting the slinger 19a. Further, of the radially inner end of the encoder 20 a, the portion that is present on the axially outer side than the encoder lip 46 covers the inner peripheral surface of the bent portion of the rotating cylindrical portion 44 and the rotating annular portion 45. , the inner circumferential surface of the part is constructed in a cylindrical surface shape having an inner diameter larger slightly than the inner diameter d ₄₄ of the slinger 19a (rotating cylindrical portion 44).

In the encoder 20a having the above-described configuration, the slinger 19a is disposed in a mold (mold), and a permanent magnet material (polymer material such as rubber or synthetic resin containing a ferromagnetic material) to be a permanent magnet. Is fixed to the slinger 19a. However, when the encoder 20a is manufactured in this way, a part of the molding die is slinger 19a (the radially inner end of the axially outer surface of the rotating ring portion 45) in order to block the flow of the polymer material. Therefore, when extracting the slinger 19a and the solidified permanent magnet material (unmagnetized encoder) from the mold, it is necessary to deform the portion to be the encoder lip portion 46 (so-called forcible removal is necessary). is there). However, the portion to be the encoder lip portion 46 contains a large amount of a ferromagnetic material such as ferrite, and is less likely to be elastically deformed than a general sealing material and is brittle. For this reason, it becomes difficult to make the protrusion amount of the encoder lip 46 sufficiently large. Therefore, in this example, the amount of protrusion of the encoder lip 46 is set so that the difference between the inner diameter of the rotating cylinder 44 and the inner diameter of the tip edge of the encoder lip 46 is about 0.5 mm. Among the radially inner end portion of the encoder 20a, the inner diameter of the portion that is present in the axially outward from the encoder lip 46 is slightly greater than the inner diameter d ₄₄ of the slinger 19a (rotating cylindrical portion 44) The reason is that, as described above, at the time of vulcanization molding, a part of the molding die is brought into contact with (injected into, or bitten into) the radially inner end portion of the outer surface in the axial direction of the rotating annular portion 45.

  The detection part 24a of the rod-shaped sensor 24 supported by the knuckle 6 is made to face and face the detection surface of the encoder 20a. When the encoder 20a rotates together with the inner member 3a, the S pole and N pole existing on the detection surface of the encoder 20a pass through the vicinity of the detection unit 24a of the sensor 24, and the output signal of the sensor 24 is set to the rotational speed of the wheel. Change accordingly. For this reason, it becomes possible to detect the rotational speed of the wheel from the output signal of the sensor 24. Therefore, the signal representing the rotational speed of the wheel can be used for control of a vehicle behavior control device such as an antilock brake system (ABS) or a traction control system (TCS).

  In order to protect the detection part 24a of the sensor 24 from a stepping stone or muddy water, the sensor cover 25a is fixed to the inner ring 12a. The sensor cover 25a is formed by pressing a metal plate, has an L-shaped cross section, and is configured in an annular shape as a whole. The sensor cover 25a is preferably made of a magnetic material in order to increase the magnetic flux density of the magnetic flux that exits the detection surface of the encoder 20a and passes through the detection unit 24a of the sensor 24. For this reason, as a metal plate which comprises the sensor cover 25a, the ferritic stainless steel plate (SUS430 type) which is a magnetic material, the martensitic stainless steel plate, or the steel plate which is a base material (for example, cold rolled steel plate) A plated steel sheet (for example, hot dip galvanized steel sheet) that has been subjected to a plating treatment (rust prevention treatment) with a base metal such as zinc having a higher ionization tendency than this steel sheet can be preferably used. In particular, a plated steel sheet can be preferably used from the viewpoint of cost reduction and press workability.

  The sensor cover 25a includes a fitting cylinder portion 26a that is formed in a cylindrical shape in the entire axial direction, and an annular bent portion that is bent at a right angle from the axially inner end portion of the fitting cylinder portion 26a toward the outside in the radial direction. 27a, of which the outer half in the axial direction of the fitting cylinder part 26a is externally fitted and fixed to the cover fitting surface 29a of the inner ring 12a. Thus, the sensor cover 25a covers the detection unit 24a of the sensor 24 from the inside in the radial direction and the inside in the axial direction.

The axial dimension of the fitting cylinder portion 26a takes into account the thickness dimension of the sensor 24 (the horizontal dimension in FIGS. 1 and 2) (so as not to hinder the insertion), and the axis of the cover fitting surface 29a. It is larger than the directional dimension (in the example shown, it is about 1.5 times). The outer diameter of the bent portion 27a is such that a labyrinth is provided between the inner peripheral surface of the mounting hole formed in the knuckle 6 for inserting the hub unit bearing 1a (the inner end portion in the axial direction of the outer member 2a). In order to form, it is larger than the internal diameter dimension of the axial direction inner end part of the outer member 2a, and smaller than an outer diameter dimension. Further, the outer diameter dimension of the fitting cylinder part 26a is from the viewpoint of preventing the magnetic flux emitted from the detected surface of the encoder 20a from being absorbed by the fitting cylinder part 26a without passing through the detection part 24a of the sensor 24. Is preferably as small as possible. However, as will be described later, the encoder lip portion 46 is formed if the outer diameter of the fitting cylinder portion 26a is made too small in order to bring the tip edge of the encoder lip portion 46 into contact with the outer peripheral surface of the fitting tube portion 26a. Cannot be removed from the mold (cannot be forcibly removed). Therefore, in this embodiment, the outer diameter _{D 26} of the fitting tube 26a, as well as to the extent to be smaller than the outer diameter _{D 28} of the slinger fitting surface 28a (the outer diameter difference) slightly (less than 0.1 mm), The degree of moldability of the encoder lip portion 46 is set to be less than 0.5 mm (less than 1% of the outer diameter D ₂₈ ) to be smaller than the inner diameter of the encoder 20a (the inner diameter of the portion outside the encoder lip portion 46 in the axial direction). Both securing and securing of the tightening allowance are achieved.

As described above, the 1/2 of the difference between the outer diameter _{D 29} of the outer diameter _{D 28} and the cover fitting surface 29a of the slinger fitting surface _{28a {(D 28 -D 29)} / 2}, the sensor cover 25a {(D ₂₈ -D ₂₉ ) / 2 = T}, which is the same as the thickness T of the metal plate used in manufacturing the metal plate. However, the plate thickness t of the fitting tube portion 26a of the sensor cover 25a manufactured by pressing the metal plate is slightly smaller than T due to the press processing (t <T). Therefore, the outer diameter _{D 26} of the fitted on the fitting tube 26a on the cover fitting surface 29a is slightly smaller than the outer diameter _{D 28} of the slinger fitting surface 28a _(D 26 _{<D 28)} . Therefore, the outer diameter _{D 26} of the fitting tube 26a is than the inner diameter _{d 44} of fitted on the slinger 19a (rotating cylindrical portion 44) to the slinger fitting surface 28a is slightly smaller _(D 26 _{<d 44} ). In this embodiment, the outer diameter D ₂₆ of the fitting tube 26a, including the portion where the encoder lip 46 is in contact, is constant over the axial length.

  With the sensor cover 25a fixed to the inner ring 12a, the axially outer end face of the fitting cylinder part 26a is brought close to and opposed to the step part 31 (second inclined surface part) constituting the outer peripheral surface of the inner ring 12a and fitted. The outer edge portion in the axial direction of the cylindrical portion 26a is made to enter the inner diameter side of the encoder 20a. Further, the tip end edge of the encoder lip portion 46 is brought into contact with the outer peripheral surface of the outer end edge portion in the axial direction of the fitting cylinder portion 26a in a state having a tightening margin over the entire circumference. Thus, in this example, the encoder lip portion 46 exists between the stepped portion 31 of the inner peripheral surface of the encoder 20a and the outer peripheral surface of the inner ring 12a and the outer end surface in the axial direction of the fitting cylindrical portion 26a. Foreign matter such as muddy water is prevented from entering the annular gap 32a where the bonding surface between 19a and the encoder 20a is exposed.

According to the hub unit bearing 1a of the present example having the above configuration, between the inner peripheral surface of the encoder 20a and the stepped portion 31 of the outer peripheral surface of the inner ring 12a and the axially outer end surface of the fitting tube portion 26a. It is possible to effectively prevent foreign matters such as muddy water from entering the annular gap 32a existing in the area.
That is, in this example, an encoder lip portion 46 extending radially inward is provided on the inner peripheral edge portion of the encoder 20a, and the leading end edge of the encoder lip portion 46 is fitted to the fitting cylinder portion constituting the sensor cover 25a. Since the outer peripheral surface of the axially outer end portion 26a is in contact with the entire circumference, it is possible to more effectively prevent foreign matter from entering the annular gap 32a as compared with the case where a labyrinth seal is provided as in the conventional structure. Therefore, it is possible to prevent rust from being generated in the inner ring 12a and the sensor cover 25a, and it is possible to prevent alkaline rust juice from staying in the annular gap 32a. As a result, even when the encoder 20a is fixed to the slinger 19a with a phenol resin adhesive, a part or the whole of the encoder 20a can be prevented from falling off the slinger 19a, and the detection accuracy of the sensor 24 is ensured. can do. In particular, when the sensor cover 25a is made of a plated steel plate that is plated with a base metal rather than a steel plate that is a base material, the rust juice is likely to be strongly alkaline, so the effect of implementing the present invention is significant. Become.

  Further, since the encoder lip portion 46 is provided on the inner side surface in the axial direction of the encoder 20a so as to be offset outwardly in the axial direction from the portion where the detection portion 24a of the sensor 24 is opposed, the front end edge of the encoder lip portion 46 Even when the encoder 20a is deformed due to contact with the outer peripheral surface of the fitting cylinder portion 26a, it is possible to prevent the deformation from affecting the detected surface. Furthermore, it is possible to prevent the portion where the deformation has occurred from protruding inward in the axial direction from the surface to be detected. Accordingly, sufficient detection accuracy of the sensor 24 can be ensured.

[Second Example of Embodiment]
A second example of the embodiment will be described with reference to FIG.
In this example, the shape of the fitting cylinder part 26b which comprises the sensor cover 25b is changed from the structure of the 1st example of embodiment. That is, in this example, the conical cylinder portion 26b is a cone whose outer diameter increases toward the inner side in the axial direction on the inner half portion in the axial direction that is not externally fitted to the cover fitting surface 29a of the inner ring 12a. A cylindrical portion 48 is provided. However, also in this example, the portion of the fitting tube portion 26b that is fitted onto the cover fitting surface 29a is configured in a cylindrical shape, and the fitting tube portion 26b that contacts the encoder lip portion 46 is outside in the axial direction. The outer diameter of the edge portion is smaller than the inner diameter of the slinger 19a.

In this example, water such as muddy water attached to the outer peripheral surface of the caulking portion 38 (see FIG. 1) and the constant velocity joint outer ring 13a (see FIG. 1) provided at the inner end of the hub wheel 11a in the axial direction is rotated. Even when adhering to the inner peripheral surface of the conical cylinder portion 48 due to the accompanying centrifugal force, the moisture can be moved axially along the inner peripheral surface of the conical cylinder portion 48 (to the bent portion 27a side). . For this reason, it can prevent effectively that a water | moisture content penetrate | invades between the internal peripheral surface of the fitting cylinder part 26b, and the cover fitting surface 29a. As a result, it can be prevented that the inner ring 12a is corroded and the durability is lowered.
About another structure and an effect, it is the same as the 1st example of embodiment.

  When implementing this invention, you may form the slit and through-hole for draining in the part which becomes a vertical direction lower side at the time of use among the fitting cylinder parts which comprise a sensor cover. In addition, an annular seal member is fixed to the inner peripheral surface of the fitting cylinder portion constituting the sensor cover, and this seal member is elastically brought into contact with the caulking portion provided on the hub wheel or the outer peripheral surface of the constant velocity joint outer ring. You can let it. In addition, the stepped portion provided on the outer peripheral surface of the inner ring constituting the inner member is not limited to the shape described in the embodiment, and if the slinger fitting surface and the cover fitting surface are continuous, The cross-sectional shape is not particularly limited.

DESCRIPTION OF SYMBOLS 1, 1a Hub unit bearing 2, 2a Outer member 3, 3a Inner member 4 Rolling body 5, 5a Outer ring track 6 Knuckle 7, 7a Stationary flange 8, 8a Inner ring track 9, 9a Rotating flange 10, 10a Spline hole 11, 11a Hub wheel 12, 12a Inner ring 13, 13a Constant velocity joint outer ring 14, 14a Spline shaft 15, 15a Nut 16, 16a Inner space 17, 17a Combination seal ring with encoder 18, 18a Seal ring 19, 19a Slinger 20, 20a Encoder 21, 21a Core metal 22, 22a Sealing material 23a-23f Seal lip 24 Sensor 24a Detection part 25, 25a, 25b Sensor cover 26, 26a, 26b Fitting cylinder part 27, 27a Bending part 28, 28a Slinger fitting surface 29, 29a Cover fitting 30 labyrinth seal 31 stepped portion 32, 32a annular gap 33 mounting hole 34 coupling member 35 coupling hole 36 stud 37 small diameter stepped portion 38 caulking portion 39 seal ring 40 cored bar 41 sealing material 42 fixed cylindrical portion 43 fixed annular portion 44 rotating cylinder Part 45 rotating ring part 46 encoder lip part 47 annular recess 48 conical cylinder part

Claims (2)

An outer member having a double-row outer ring raceway on the inner peripheral surface, which is supported and fixed to the suspension device and does not rotate;
An inner member that is formed by coupling and fixing a hub ring and an inner ring, and has a double-row inner ring raceway on an outer peripheral surface, and a wheel is fixed and rotates together with the wheel,
A plurality of rolling elements provided between the outer ring raceways and the inner ring raceways so as to roll freely;
It closes the axially inner end opening of the internal space existing between the inner peripheral surface of the outer member and the outer peripheral surface of the inner member, the seal ring fixed to the outer member, and the inner ring A combined seal ring with an encoder having a slinger that is externally fitted and fixed, and an annular encoder supported by the slinger;
Protects a sensor disposed opposite to the inner side surface of the encoder in the axial direction, and a fitting cylinder part fitted and fixed to the inner ring, and radially outward from an axial inner end of the fitting cylinder part. A sensor cover having a bent portion that is bent toward the
On the outer peripheral surface of the inner ring, a slinger fitting surface on which the slinger is fitted and fixed, and the fitting cylinder portion provided on the inner side in the axial direction and having a smaller diameter than the slinger fitting surface are fitted and fixed. A cover fitting surface, and a step portion connecting the cover fitting surface and the slinger fitting surface,
An encoder lip portion is provided on the inner peripheral edge of the encoder, and the encoder lip portion is offset outward in the axial direction from the portion of the inner surface in the axial direction of the encoder that faces the detection portion of the sensor. A hub unit bearing, wherein a tip edge of the encoder lip portion is in contact with the outer peripheral surface of the axially outer end portion of the fitting tube portion having an outer diameter smaller than the inner diameter of the slinger.   The hub unit bearing according to claim 1, wherein the sensor cover is made of a plated steel plate that is plated with a metal that is baser than a steel plate that is a base material.

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