JP2019105315A - Hub unit bearing - Google Patents

Abstract

To obtain a structure in which magnetic rubber for forming a labyrinth seal is hardly exfoliated from an end part of a core grid in an axial direction regardless of a kind of a magnetic metal plate being a raw material of the core grid constituting an encoder.SOLUTION: A core grid 30 of an encoder 22 has: a fitting cylinder part 32 which is externally fit to an inner end part of an outer ring 18 in an axial direction; a side plate part 33 whose outside face in the axial direction abuts on the inner end face of the outer ring 18 in the axial direction; and a hang-out part 34 which is arranged between the fitting cylinder part 32 and a side plate part 33, and in which a hang-out amount from the outer ring 18 to the inside of the axial direction is larger than a thickness dimension of a magnetic metal plate being a raw material of the core grid 30, and the inner end face in the axial direction is constituted of a side face of the magnetic metal plate. The magnetic rubber 31 of the encoder 22 covers an external peripheral face of the fitting cylinder part 32 and the inner end face of the hang-out part 34 in the axial direction, and has a magnetization part 39 in which the S-pole and the N-pole are alternately arranged in a circumferential direction at an external peripheral face of the magnetic rubber 31.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a hub unit bearing for rotatably supporting a wheel of a vehicle with respect to a suspension system.

  In an outer ring rotating hub unit bearing provided with an outer ring that rotates with the wheel, an encoder for detecting a rotational speed may be attached to an axially inner end portion of the outer ring. Also, in recent years, the magnetic rubber constituting the encoder is used to form an axially inward overhanging flange portion, and the axial inner end portion (tip end portion) of the flange portion and a stationary flange of an axle etc. By constructing a labyrinth seal between the member and the member, it is considered to protect the sealing device that closes the axial inner end opening of the internal space of the hub unit bearing.

  However, the magnetic rubber constituting the encoder contains a large amount of ferrite powder at about 80% by weight to 90% by weight, and the amount of rubber serving as a base material is as small as about 10% by weight to 20% by weight. (brittle). For this reason, there is a problem that when the ridge portion is configured using only magnetic rubber, the ridge portion is easily broken.

  On the other hand, Japanese Patent Application Publication No. 2008-94243 describes an outer ring rotating hub unit bearing in which such a problem is alleviated. In this hub unit bearing, as shown in FIG. 5, an encoder 2 is attached to the axially inner end portion of the outer ring 1 rotating with the wheel. Further, the axially inner end opening of the internal space 15 in which the rolling element 14 is installed, which is present between the inner peripheral surface of the outer ring 1 and the outer peripheral surface of the inner ring 11, is closed by the sealing device 16.

  With regard to the hub unit bearing, the axially inner side is on the right side in each of the figures, which is the center in the width direction of the vehicle in the assembled state to the vehicle, and the axially outer side is the width direction outer side of the vehicle in the assembled state to the vehicle The left side in each figure.

  The encoder 2 includes a core metal 3 made of a magnetic metal plate and a magnetic rubber 4.

  The metal core 3 is formed along the axially inner end face of the outer ring 1 from the axially inner end of the cylindrical large diameter cylindrical portion 5 externally fitted to the axially inner end portion of the outer ring 1 and the large diameter cylindrical portion 5. A radially inward extending annular side plate portion 6 and a cylindrical small diameter cylindrical portion 7 extending axially inward from the radially inner end of the side plate portion 6 are provided.

  The magnetic rubber 4 is integrally configured as a whole, and has a cylindrical portion covering the outer peripheral surface of the large diameter cylindrical portion 5 and a cylindrical elastic cylindrical portion 9 in which the small diameter cylindrical portion 7 is embedded. .

  In the magnetic rubber 4, the outer peripheral surface of the cylindrical portion covering the outer peripheral surface of the large-diameter cylindrical portion 5 is magnetized, so that the magnetized portion 8 in which the S pole and the N pole are alternately arranged in the circumferential direction It has become. The encoder 2 constitutes a rotational speed detection device together with a sensor 17 mounted on the vehicle body side, and the sensor 17 is opposed to the magnetized portion 8.

  The elastic cylindrical portion 9 and the small diameter cylindrical portion 7 constitute a cylindrical collar portion 10. Further, an axially inner end portion of the elastic cylindrical portion 9 which is a tip end portion of the collar portion 10 is closely opposed to an axially outer surface of a stationary flange (stationary member) 12 of an axle on which the inner ring 11 is externally fitted. Thus, the labyrinth seal 13 is formed between the axially inner end portion of the elastic cylindrical portion 9 and the axially outer surface of the stationary flange 12.

  The seal device 16 is protected by the collar 10 and the labyrinth seal 13. That is, the seal device 16 is protected by suppressing or preventing foreign matter such as muddy water and pebbles that have jumped up from the road surface from reaching the seal device 16 by the buttocks 10 and the labyrinth seal 13.

  In the hub unit bearing described above, the collar portion 10 is constituted by the elastic cylindrical portion 9 of the magnetic rubber 4 and the small diameter cylindrical portion 7 of the core 3 embedded in the elastic cylindrical portion 9. That is, the elastic cylindrical portion 9 of the magnetic rubber 4 is reinforced by the small diameter cylindrical portion 7 of the core 3. For this reason, the collar portion 10 is less likely to be damaged than in the case where it is configured using only the magnetic rubber 4.

Unexamined-Japanese-Patent No. 2008-94243

  The hub unit bearing described in Japanese Patent Application Laid-Open No. 2008-94243 has room for improvement in terms of suppressing damage to the tip end of the flange portion 10.

  That is, the axially inner end portion of the elastic cylindrical portion 9 which is the tip end portion of the collar portion 10 is bonded to the axially inner end surface of the small diameter cylindrical portion 7 of the core 3. Here, the axially inner end surface of the small diameter cylindrical portion 7 is a fractured surface of the magnetic metal plate that constitutes the core 3, and the ability to bond the rubber is (extremely) low. Therefore, for example, when the encoder 2 is transported, the axially inner end of the elastic cylindrical portion 9 collides with a surrounding object, a pebble is caught in the labyrinth seal 13 when the automobile is driven, or the outer inner ring When an external force is applied to the axially inner end of the elastic cylindrical portion 9 due to relative inclination or the like, the axially inner end of the elastic cylindrical portion 9 is from the axially inner end surface of the small diameter cylindrical portion 7 It is easy to peel off and break (drop out), and furthermore, since the magnetic rubber has poor elasticity (brittleness) as described above, a dropout chain (a phenomenon in which the adjacent part continues to drop when 1 point is dropped) occurs. easy. Further, in the case where the core metal 3 is made of a material susceptible to rusting, such as a low carbon steel plate such as a deep drawn steel plate, for example, the alkali generated by rust causes destruction of the rubber adhesive layer to further promote dropout chain. Therefore, the labyrinth seal 13 can not be made narrow enough.

  In addition, regarding the magnetic metal plate which constitutes the core metal 3, if an rustproof steel plate such as a stainless steel plate is used, it is possible to prevent the chain of falling off due to the breakage of the rubber adhesive layer described above. Since the adhesion performance of rubber is low, the axially inner end portion of the elastic cylindrical portion 9 is easily peeled from the axially inner end portion of the small diameter cylindrical portion 7. In addition, stainless steel plates are more expensive than low carbon steel plates, and there is a problem that pressing is more difficult than low carbon steel plates.

  The present invention has been made in view of the above-described circumstances, and an object thereof is to form a labyrinth seal from the axial inner end portion of the core regardless of the type of magnetic metal plate constituting the core. The present invention is to realize a structure that can make it difficult to peel off the magnetic rubber to be removed.

The hub unit bearing according to the present invention comprises an outer ring, an inner member, a plurality of rolling elements, a seal device, and an encoder.
The outer ring has an outer ring raceway on its inner circumferential surface and rotates with the wheel in use.
The inner ring has an inner ring track on the outer circumferential surface and does not rotate in use.
The plurality of rolling elements are disposed between the outer ring raceway and the inner ring raceway.
The sealing device closes an axially inner end opening of an internal space existing between the inner peripheral surface of the outer ring and the outer peripheral surface of the inner member.
The encoder is attached to an axially inner end portion of the outer ring, and includes a core metal made of a magnetic metal plate and magnetic rubber.
The cored bar includes a fitting cylindrical portion externally fitted to the axially inner end portion of the outer ring, an annular side plate portion in which an axially outer surface is brought into contact with an axially inner end surface of the outer ring, It is provided between the axially inner end portion of the fitting cylinder portion and the radially outer end portion of the side plate portion, and protrudes inward in the axial direction with respect to the axially inner end surface of the outer ring, and also axially inward. The projecting amount is larger than the thickness dimension of the magnetic metal plate, and the axial inner end surface has an overhanging portion formed by the side surface of the magnetic metal plate.
The magnetic rubber covers the outer peripheral surface of the fitting cylindrical portion and the axially inner end surface of the overhang portion, and on the outer peripheral surface of the magnetic rubber, the S pole and the N pole alternate in the circumferential direction. It has the magnetization part arrange | positioned.

When the present invention is practiced, for example, the following configuration can be employed.
That is, the overhanging portion has an outer diameter side cylindrical portion extending inward in the axial direction from an axial inner end portion of the fitting cylindrical portion. In the magnetic rubber, an outer peripheral surface of a portion covering the outer peripheral surface of the fitting cylindrical portion and the outer diameter side cylindrical portion is the magnetized portion.

  In the case of carrying out the present invention, for example, the magnetic metal plate as a material of the core metal can be a low carbon steel plate such as a deep drawn steel plate. In addition, low carbon steel is carbon steel whose carbon content is 0.25 mass% or less.

  According to the hub unit bearing of the present invention, the magnetic rubber for forming the labyrinth seal can be hardly peeled off from the axial inner end of the core regardless of the type of magnetic metal plate constituting the core. .

FIG. 1 is a half sectional view of a hub unit bearing according to a first example of the embodiment. FIG. 2 is an enlarged view of the encoder in FIG. 1 and its periphery. FIG. 3 is a cross-sectional view showing a state where the magnetic rubber of the encoder has been vulcanized and formed in the cavity of the mold apparatus in the first example of the embodiment. FIG. 4 is a view corresponding to FIG. 2 and showing a second example of the embodiment. FIG. 5 is a partial cross-sectional view showing one example of a conventional hub unit bearing.

First Example of Embodiment
A first example of the embodiment will be described using FIGS. 1 to 3.
The hub unit bearing of this embodiment is for a driven wheel, and includes an outer ring (hub) 18, a pair of inner rings 19 which are inward members, a plurality of rolling elements 20, a sealing device 21, and an encoder 22. Have.

  The outer ring 18 has a double row outer ring raceway 23 on its inner circumferential surface, and has a rotating flange 24 projecting radially outward at an axially outer portion. The rotating flange 24 has mounting holes 25 at a plurality of circumferential positions. In a state where the hub unit bearing of this example is assembled to a car, the wheel and the rotating body for braking (disk or drum) are supported and fixed to the rotating flange 24 using a hub bolt press-fitted or screwed into the mounting hole 25. Ru. Thus, the outer ring 18 rotates with the wheel and the braking rotor.

  The pair of inner rings 19 is axially arranged on the inner diameter side of the outer ring 18 and has an inner ring race 26 on the outer circumferential surface of each. That is, on the outer peripheral surface of the pair of inner rings 19, double rows of inner ring races 26 are provided. With the hub unit bearing of this embodiment assembled to a vehicle, the pair of inner rings 19 is externally fixed to the axle and does not rotate.

  A plurality of rolling elements 20 are arranged in each row between the double row outer ring raceway 23 and the double row inner ring race 26. In the illustrated example, a ball is used as the rolling element 20, but a tapered roller may be used as the rolling element.

  The seal device 21 closes an axially inner end opening of an internal space 27 provided between the inner peripheral surface of the outer ring 18 and the outer peripheral surface of the pair of inner rings 19 in which a plurality of rolling elements 20 are installed. . In the illustrated example, the seal device 21 is a combined seal ring, and the seal ring 28 is internally fitted and fixed to the axially inner end of the outer ring 18 and is externally fitted to the axially inner end of the axially inner inner ring 19. And a slinger 29 which is a fixed sliding ring. The tip end portions of the plurality of seal lips constituting the seal ring 28 are brought into sliding contact with the surface of the slinger 29 to seal the axial inner end opening of the internal space 27. In the hub unit bearing of this embodiment, a hub cap (not shown) is fitted to the axial outer end opening of the outer ring 18 after assembly to the vehicle body, whereby the axial outer end opening of the internal space 27 is sealed.

  The encoder 22 is attached to the axially inner end of the outer ring 18. The encoder 22 includes a cored bar 30 and a magnetic rubber 31.

  The cored bar 30 is a magnetic metal plate and made of a low carbon steel plate such as a deep drawn steel plate, and has a substantially L-shaped cross section, and the whole is formed in an annular shape. Such a core metal 30 has a cylindrical fitting cylindrical portion 32 constituting a radially outer portion, an annular side plate portion 33 constituting a radially inner portion, and an axially inner end of the fitting cylindrical portion 32. And a protruding portion 34 provided between the portion and the radial outer end of the side plate portion 33. The cored bar 30 is formed by pressing a magnetic metal plate, and the core metal 30 is broken at two places of the axial outer end face of the fitting cylindrical portion 32 and the radial inner end face of the side plate portion 33. There is an end face which is a cross section. And the surface of the core metal 30 is comprised by the side surface of a magnetic metal plate except these two end surfaces.

  The fitting cylindrical portion 32 is composed of a press-fit fitting portion 35 which constitutes an axially inner portion, and a non-press-fit fitting portion 36 which constitutes an axially outer portion. The press-fit fitting portion 35 is formed in a single cylindrical shape whose inner diameter does not change in the axial direction. The non-press-fit fitting portion 36 extends axially outward from the axial outer end of the press-fit fitting portion 35, and is formed in a conical cylindrical shape inclined in a direction in which the inner diameter dimension increases toward the axial direction. ing. Such non-press-fit fitting portion 36 functions as a guide for press-fitting the press-fit fitting portion 35 into the outer ring cylindrical surface portion 37 described later, and part of the magnetic rubber 31 covering the non-press-fit fitting portion 36 The inner periphery of the non-press-fit fitting portion 36 is bonded to the inner peripheral surface (a portion other than the fracture surface) of the non-press-fit fit portion 36.

  On the other hand, the outer ring 18 has a single cylindrical outer ring cylindrical surface portion 37 coaxial with the central axis of the outer ring 18 on the outer peripheral surface at the axially inner end portion. The press-fit fitting portion 35 is press-fit into the outer ring cylindrical surface portion 37 from the inside in the axial direction, and is externally fitted and fixed to the outer ring cylindrical surface portion 37 by tight fitting. On the other hand, the non-press-fit fitting portion 36 is externally fitted to the outer ring cylindrical surface portion 37 with a clearance fit. Between the inner peripheral surface of the non-press-fit fitting portion 36 and the outer ring cylindrical surface portion 37, there is a wedge-shaped gap in which the width dimension in the radial direction becomes larger toward the axially outer side.

  The side plate portion 33 is configured in a single circular ring coaxial with the fitting cylinder portion 32. On the other hand, the outer ring 18 has an annular outer ring flat surface portion 38 orthogonal to the central axis of the outer ring 18 at the axially inner end surface. The axially outer side surface of the side plate portion 33 is in contact with the outer ring flat portion 38. Then, by this contact, axial positioning of the encoder 22 with respect to the outer ring 18 is achieved.

  The overhanging portion 34 has an arc-like (substantially semicircular) cross-sectional shape in which the inner side in the axial direction is convex, and the whole is configured in an annular shape. The radially outer end portion of the overhanging portion 34 is coupled to the axially inner end portion of the fitting cylindrical portion 32, and the radially inner end portion is coupled to the radially outer end portion of the side plate portion 33. Further, in a state where the fitting cylindrical portion 32 is externally fitted to the outer ring cylindrical surface portion 37 and the axial outer surface of the side plate portion 33 abuts on the outer ring flat portion 38, the overhanging portion 34 is closer to the outer ring flat portion 38. It also projects inward in the axial direction. In other words, a gap having a substantially semicircular cross section is present between the axially outer surface of the overhanging portion 34 and the outer ring flat portion 38. The amount of inward extension of the overhanging portion 34 with respect to the outer ring flat surface portion 38 is larger than the thickness dimension of the magnetic metal plate which is the material of the core 30. Therefore, the axially inner portion of the overhanging portion 34 projects inward in the axial direction with respect to the axially inner side surface of the side plate portion 33.

  The magnetic rubber 31 is formed in an annular shape by rubber mixed with ferrite powder, and is adhered to the core metal 30 by vulcanization. The magnetic rubber 31 contains a large amount of ferrite powder at about 80% by weight to 90% by weight, and the amount of rubber serving as a base material is small at about 10% by weight to 20% by weight, so the elasticity is poor (brittle) .

  The magnetic rubber 31 has an axially outer end inner peripheral surface (inner peripheral surface of the non-press-fit fitting portion 36) of the fitting cylindrical portion 32 and an axially outer end surface (non-press-fit fitting portion 36) of the fitting cylindrical portion 32. Axially outer end surface), outer peripheral surface of fitting cylindrical portion 32, outer surface of overhanging portion 34 (side surface opposite to outer ring 18 with respect to thickness direction), axially inner side surface of side plate portion 33, side plate It covers a continuous range with the radial inner end face of the portion 33.

  Further, the magnetic rubber 31 is magnetized on the outer peripheral surface of the portion covering the outer peripheral surface of the fitting cylindrical portion 32 and the overhang portion 34, whereby the S pole and the N pole are alternately arranged in the circumferential direction Also, it has a cylindrical magnetized portion 39. The encoder 22 constitutes a rotational speed detection device together with the sensor 40 mounted on the vehicle body side, and the sensor 40 is opposed to the magnetized portion 39.

  Further, the magnetic rubber 31 and the overhanging portion 34 together with the overhanging portion 34 constitute a flange portion 45 projecting inward in the axial direction with respect to the outer ring flat portion 38. Further, the magnetic rubber 31 has an axially inner end portion which is a portion covering the axially inner end surface (the side surface of the magnetic metal plate constituting the axially inner surface) of the overhang portion 34 as a seal forming portion 53. There is. An axially inner surface of the seal forming portion 53 is an annular flat surface perpendicular to the central axis of the outer ring 18. The axial direction of the stationary member 43 which does not rotate in use, such as a stationary flange provided on an axle to which the inner ring 19 is fixedly fitted, and a knuckle constituting a suspension device, is formed on the axially inner surface of the seal forming portion 53. The outer surface (in the illustrated example, a flat surface parallel to the inner surface in the axial direction of the seal forming portion 53) is in close proximity to the entire circumference. Thus, a radially long labyrinth seal 44 is formed between the axially inner side surface of the seal forming portion 53 and the axially outer side surface of the stationary member 43.

  The seal device 21 is protected by the collar 45 and the labyrinth seal 44. That is, the seal device 21 is protected by suppressing or preventing the foreign matter such as muddy water or pebbles that has jumped up from the road surface from reaching the seal device 21 by the flange portion 45 and the labyrinth seal 44.

  Further, the magnetic rubber 31 has a diameter that is larger than the inner diameter of the press-fit fitting portion 35 in a free state in a portion covering the inner circumferential surface (inner circumferential surface of the non-press-fit fitting portion 36) of the axially outer end portion of the fitting cylindrical portion 32. Has a smaller outer diameter side gasket portion 41. Then, by allowing such an outer diameter side gasket portion 41 to elastically abut on the outer ring cylindrical surface portion 37, muddy water from the axial direction outer side between the outer ring cylindrical surface portion 37 and the inner peripheral surface of the press-fit fitting portion 35. And other foreign matter are prevented from intruding. FIG. 2 shows the shape of the outer gasket portion 41 in the free state.

  In addition, the magnetic rubber 31 has an inner side gasket portion 42 protruding outward in the axial direction with respect to the axial outer surface of the side plate portion 33 at the axially outer end portion of the portion covering the radial inner end surface of the side plate portion 33. doing. Then, when such an inner diameter side gasket portion 42 is elastically brought into contact with the outer ring flat surface portion 38, foreign matter such as muddy water intrudes between the outer ring flat surface portion 38 and the side plate portion 33 from inside in the radial direction. , The core metal 3 is prevented from being exposed to the outside. FIG. 2 shows the shape of the inner side gasket portion 42 in the free state.

  In the hub unit bearing of the present embodiment as described above, the seal forming portion 53 which is the axially inner end portion of the magnetic rubber 31 constituting the encoder 22 is the axially inner end surface of the core 30, that is, the protruding portion 34 It is vulcanized and bonded to the axial inner end surface. Here, the axially inner end surface of the overhanging portion 34 is formed by a side surface which is not an end surface which is a fracture surface among the magnetic metal plates constituting the core 30. For this reason, regardless of the type of this magnetic metal plate, that is, as in this example, even if this magnetic metal plate is a low carbon steel plate such as a deep drawn steel plate, the seal against the inner end face in the axial direction of the overhang portion 34 The adhesion of the forming portion 53 can be strengthened. Therefore, when an external force is applied to the seal forming portion 53, for example, when the seal forming portion 53 collides with a surrounding object during conveyance of the encoder 22 or a pebble is caught in the labyrinth seal 44 during operation of the vehicle. However, it is possible to make the seal forming portion 53 less likely to peel off from the axial direction inner end surface of the overhang portion 34 (make it difficult to come off).

  Further, in the present example, the cored bar 30 has an overhanging portion 34 that protrudes inward in the axial direction between the fitting cylindrical portion 32 and the side plate portion 33, and the magnetism that constitutes the cored bar 30. As the metal plate, a low carbon steel plate such as a deep drawn steel plate is used which is inexpensive and easy to press compared to a stainless steel plate. Therefore, not only the material cost of the core metal 30 can be suppressed, but also the core metal 30 can be made with high accuracy. Specifically, when the cored bar 30 is pressed, each portion of the cored bar 30 is stretched, and the fitting cylindrical portion 32, the side plate portion 33, and the like can be formed with high accuracy. As a result, the adhesion of the inner peripheral surface of the press-fit fitting portion 35 to the outer ring cylindrical surface portion 37 and the adhesion of the axial outer surface of the side plate portion 33 to the outer ring flat portion 38 can be increased. The sealing effect of the radial side gasket portion 41 and the inner radial side gasket portion 42 can be enhanced.

  Further, in this example, as shown in FIG. 3, the magnetic rubber 31 constituting the encoder 22 is vulcanized and formed in the cavity 48 provided between the first mold 46 and the second mold 47. Then, when the encoder 22 is extracted axially (rightward in FIG. 3) with respect to the shaft portion 49 of the first mold 46 inserted to the inner diameter side of the encoder 22, the outer diameter side gasket It is necessary to forcibly remove the part 41. That is, of the shaft portion 49, the portion positioned on the right side of FIG. 3 with respect to the outer diameter side gasket portion 41 becomes the large diameter portion 50 whose outer diameter dimension is larger than the inner diameter dimension of the outer diameter side gasket portion 41. ing. In addition, the dashed-dotted line (alpha) in FIG. 3 has shown the virtual cylindrical surface inscribed in the outer diameter side gasket part 41. As shown in FIG. Therefore, when removing the encoder 22 in the axial direction (rightward in FIG. 3) with respect to the shaft portion 49, the outer diameter side gasket portion 41 is elastically expanded in diameter and the outer side with respect to the large diameter portion 50. It is necessary to make the radial side gasket portion 41 get over in the axial direction. This operation is referred to as forced removal of the outer diameter side gasket portion 41.

  On the other hand, as described above, the magnetic rubber 31 (outer side gasket portion 41) has poor elasticity (brittleness). Therefore, if the radial height of the outer gasket portion 41, that is, the tightening margin of the outer gasket portion 41 with respect to the outer ring cylindrical surface portion 37 is excessively increased, the outer gasket is used when performing the above-described forced removal. The part 41 is easily broken. Therefore, the interference of the radially outer gasket portion 41 with respect to the outer ring cylindrical surface portion 37 can not be made so large.

  However, in the present embodiment, as described above, the cored bar 30 can be made with high accuracy. Moreover, along with this, the dimensional accuracy of the outer diameter side gasket portion 41 can be made favorable. Therefore, even if the interference of the outer diameter side gasket portion 41 with respect to the outer ring cylindrical surface portion 37 is small, the sealing effect by the outer diameter side gasket portion 41 can be enhanced.

Second Example of Embodiment
A second example of the embodiment will be described with reference to FIG.
In this example, the axial dimension of the overhanging portion 34a of the cored bar 30a constituting the encoder 22a is larger than that of the first example of the embodiment. For this purpose, specifically, a cylindrical outer diameter side extending inward in the axial direction from the axially inner end portion of the fitting cylindrical portion 32 at the proximal end side portion (axially outer portion) of the projecting portion 34a A cylindrical portion 51 and a cylindrical inner side cylindrical portion 52 extending inward in the axial direction from the radial outer end of the side plate portion 33 are additionally provided. Further, in the present embodiment, the axial dimension of the cylindrical magnetized portion 39a present on the outer peripheral surface of the magnetic rubber 31a constituting the encoder 22a is the same as the axial dimension of the outer diameter side tubular portion 51. It is longer than the case of the first example. Accordingly, the output of the encoder 22a (the magnetic flux density around the magnetized portion 39a) can be increased accordingly.
The other configurations and functions are the same as in the first example of the embodiment.

When carrying out the present invention, the type of magnetic metal plate constituting the cored bar is not particularly limited.
Further, the inward member constituting the hub unit bearing may be a shaft member having an inner ring raceway on the outer peripheral surface.

DESCRIPTION OF SYMBOLS 1 outer ring 2 encoder 3 core metal 4 magnetic rubber 5 large diameter cylindrical portion 6 side plate portion 7 small diameter cylindrical portion 8 magnetized portion 9 elastic cylindrical portion 10 collar portion 11 inner ring 12 stationary flange 13 labyrinth seal 14 rolling element 15 internal space 16 sealing device 17 sensor 18 outer ring 19 inner ring 20 rolling element 21 seal device 22, 22a encoder 23 outer ring raceway 24 rotary flange 25 mounting hole 26 inner ring raceway 27 inner space 28 seal ring 29 slinger 30, 30a core metal 31, 31a magnetic rubber 32 fitting cylinder Part 33 Side plate part 34, 34a Overhang part 35 Press fit fitting part 36 Non press fit fitting part 37 Outer ring cylindrical surface part 38 Outer ring flat part 39, 39a Magnetized part 40 Sensor 41 Outer diameter side gasket part 42 Inner diameter side gasket part 43 Stationary Member 44 Labyrinth seal 45 butt 46 first mold 47 second gold 48 cavity 49 shaft portion 50 large diameter portion 51 the outer diameter side cylindrical portion 52 the inner diameter side cylindrical portion 53 seal forming portion

Claims (3)

An outer ring having an outer ring track on the inner circumferential surface and rotating with the wheel in use;
An inner member having an inner ring raceway on the outer peripheral surface and not rotating in use;
A plurality of rolling elements disposed between the outer ring raceway and the inner ring raceway;
A sealing device for closing an axially inner end opening of an inner space existing between an inner peripheral surface of the outer ring and an outer peripheral surface of the inner member;
An encoder attached to an axial inner end of the outer ring,
The encoder has a core metal made of a magnetic metal plate and a magnetic rubber,
The cored bar includes a fitting cylindrical portion externally fitted to the axially inner end portion of the outer ring, an annular side plate portion in which an axially outer surface is brought into contact with an axially inner end surface of the outer ring, It is provided between the axially inner end portion of the fitting cylinder portion and the radially outer end portion of the side plate portion, and protrudes inward in the axial direction with respect to the axially inner end surface of the outer ring, and also axially inward. And an overhanging portion in which an amount of extension is larger than a thickness dimension of the magnetic metal plate, and an axial inner end surface is formed by a side surface of the magnetic metal plate,
The magnetic rubber covers the outer peripheral surface of the fitting cylindrical portion and the axially inner end surface of the overhang portion, and on the outer peripheral surface of the magnetic rubber, the S pole and the N pole alternate in the circumferential direction. Have a magnetizing section arranged,
Hub unit bearings. The projecting portion has an outer diameter side cylindrical portion extending inward in the axial direction from an axial inner end portion of the fitting cylindrical portion,
In the magnetic rubber, an outer peripheral surface of a portion covering the outer peripheral surface of the fitting cylindrical portion and the outer diameter side cylindrical portion is the magnetized portion.
The hub unit bearing according to claim 1. The magnetic metal plate as a material of the core metal is a low carbon steel plate,
The hub unit bearing according to claim 1.

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