JP2016050667A - Rolling bearing unit with encoder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a structure of a rolling bearing unit with an encoder, capable of ensuring sufficient sealability between a seal material disposed on an outer peripheral face of a cap and an inner peripheral face of an outer ring.SOLUTION: A fitting cylindrical portion 21a constituting a cap 20a is composed of a main body cylindrical portion 24a internally fitted and fixed to a first fitting face 23 formed on an inner peripheral face of an axial inner end part of an outer ring 2 by interference fitting, and a non-contact cylindrical portion 25a disposed at an axial inner side with respect to the main body cylindrical portion 24a, and not kept in contact with the inner peripheral face of the outer ring 2. Further a seal material 26a is fixed to an outer peripheral face of the non-contact cylindrical portion 25a, and the seal material 26a is composed of a lip main body 27a having a substantially trapezoidal cross-sectional shape, and kept in contact with a seal face 50 having an inner diameter dimension larger than the first fitting face 23a of the inner peripheral face of the outer ring 2 at its tip edge, and an auxiliary lip 49 formed on a radial outer part in an extended state, and kept in contact with a chamfer portion 52 formed on an axial inner side of the seal face 50 at its axial side face in a used state.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an improvement in a rolling bearing unit with an encoder that supports, for example, a wheel of an automobile so as to be rotatable with respect to a suspension device and is used for detecting the rotational speed of the wheel.

  2. Description of the Related Art Conventionally, various types of rolling bearing units have been known as rolling bearing units that support a wheel on an automobile suspension so as to be rotatable and also include a rotation speed detection device for detecting the rotation speed of the wheel. In any structure, the detection part of the sensor supported and fixed to the non-rotating part is opposed to the detection surface of the encoder supported and fixed to a part of the hub that rotates together with the wheel. And it is comprised so that the rotational speed of the wheel which rotates with an encoder may be calculated | required based on the frequency or the period of the output signal of a sensor which changes with rotation of an encoder.

  Use this encoder to prevent the encoders that make up such a rolling bearing unit with a rotational speed detector from being damaged by adhesion of muddy water or dust, or when foreign particles such as magnetic powder adhere to the encoder. In order to prevent the reliability of the detected rotation speed from being impaired, a structure in which the encoder is separated from the outside using a cap (cover) or the like has been conventionally considered. 6 and 7 show an example of a conventional structure described in Patent Document 1. FIG.

  A rolling bearing unit 1 with an encoder having a conventional structure is configured such that a hub 3 is rotatably supported via a plurality of rolling elements 4 and 4 on the inner diameter side of an outer ring 2. Of these, the outer ring 2 is provided with a stationary flange 6 on the outer peripheral surface for supporting and fixing to a knuckle 5 as a suspension device, and double row outer ring raceways 7a and 7b on the inner peripheral surface. Further, the hub 3 is provided with double row inner ring raceways 8a and 8b and a rotation side flange 9 for supporting and fixing a rotor constituting a wheel and a disc brake on the outer peripheral surface. Further, a plurality of rolling elements 4, 4 are provided between the outer ring raceways 7a, 7b and the inner ring raceways 8a, 8b so as to be freely rollable in each row.

  The hub 3 is formed by coupling and fixing a hub body 10 and an inner ring 11. Of these, the hub body 10 is a portion closer to the outer end in the axial direction on the outer peripheral surface (outside with respect to the axial direction means the outer side in the width direction of the vehicle body when assembled to the knuckle 5 and is the left side of each figure. On the contrary, the right side of each figure, which is the center side in the width direction of the vehicle body, is referred to as the inside in the axial direction (the same applies to the entire specification and claims). The inner ring raceway 8a on the outer side in the axial direction of the inner ring raceways 8a and 8b is provided in the portion, and the small-diameter step portion 12 is provided on the portion closer to the inner end in the axial direction. In addition, the inner ring 11 is provided with an inner ring raceway 8b on the outer peripheral surface on the inner side in the axial direction of the inner ring raceways 8a and 8b. Such an inner ring 11 is in a state of being fitted and fixed to the small-diameter step portion 12 of the hub main body 10, and a caulking portion 13 in which the axial inner end surface of the inner ring 11 is formed at the axial inner end portion of the hub main body 10. The hub body 10 is coupled and fixed to the hub body 10.

  An encoder 15 is externally fitted and fixed to a shoulder 14 provided in the inner half of the inner ring 11 in the axial direction. Thus, the encoder 15 is supported and fixed to the hub 3 concentrically with the hub 3. The encoder 15 includes a support ring 16 which is L-shaped in cross section and has an annular shape as a whole, and an encoder body 17 made of a permanent magnet fixed to the support ring 16. The encoder body 17 is magnetized in the axial direction, and by alternately changing the magnetization direction in the circumferential direction at equal intervals, the S pole and the N pole Are arranged alternately and at equal intervals.

  Further, a seal ring 18 is mounted between the inner peripheral surface of the outer end portion in the axial direction of the outer ring 2 and the outer peripheral surface of the intermediate portion in the axial direction of the hub 3, and the inner portion existing between the two peripheral surfaces. The axially outer side opening of the space 19 is blocked. On the other hand, the axially inner side opening of the inner space 19 is closed by a cap (inner cap) 20.

  The cap 20 is formed by subjecting an austenitic stainless steel plate to press working. The cap 20 has a bottomed cylindrical shape as a whole, and includes a fitting tube portion 21 extending in the axial direction, and the fitting tube portion 21. And a bottom plate portion 22 extending radially inward from the axial inner end edge. Of these, the fitting cylinder portion 21 is provided on the outer portion in the axial direction, and is fitted and fixed to the first fitting surface 23 formed on the inner peripheral surface of the outer ring 2 near the inner end in the axial direction by an interference fit. And a non-contact cylindrical portion 25 having a partially conical cylindrical shape, which is provided in an axially inner portion and is inclined in a radially inward direction as it goes inward in the axial direction. The non-contact cylindrical portion 25 does not contact the inner peripheral surface of the outer ring 2 when the cap 20 is attached. When the cap 20 is mounted, the outer surface in the axial direction (the surface on the inner space 19 side) of the bottom plate portion 22 is closely opposed to the detected surface of the encoder body 17 through a minute gap. .

  A rubber sealing material 26 is fixed to the outer peripheral surface of the non-contact cylindrical portion 25 by vulcanization adhesion. The sealing material 26 is provided with a lip main body 27 having an outer diameter larger than the outer diameter of the fitting cylinder 21 (main cylinder 24) in a free state. Then, with the cap 20 mounted, the tip edge (outer peripheral edge) of the lip body 27 is brought into contact with the first fitting surface 23 with a tightening margin.

  A sensor holding member (outer cap) 28 is provided on the axially inner side of the cap 20 having the above-described configuration. The sensor holding member 28 is used to hold a sensor 29 for detecting the rotation speed, and is axially more than the portion of the inner peripheral surface of the outer ring 2 where the cap 20 is fitted and fixed. Internally fitted and fixed. The sensor holding member 28 is formed by pressing a metal plate, and has a bottomed cylindrical shape as a whole, and includes a cylindrical portion 30 that extends in the axial direction and an inner end in the axial direction of the cylindrical portion 30. And a bottom 31 extending radially inward from the edge. The sensor holding member 28 having such a configuration is configured such that the axially outer half portion of the cylindrical portion 30 is formed on the inner peripheral surface of the axially inner end portion of the outer ring 2 in a state of being mounted on the outer ring 2. While the inner fitting is fixed to the two fitting surfaces 32 by an interference fit, the axially outer side surface of the outward flange portion 33 formed at the axially intermediate portion of the cylindrical portion 30 is abutted against the axially inner end surface of the outer ring 2. ing. A through hole 34 is formed in a portion of the bottom portion 31 facing the detected surface of the encoder body 17 in the axial direction, and the detection portion of the sensor 29 is inserted into the through hole 34. Yes. Further, a mounting hole 35 is formed in the bottom portion 31 in the radially inner portion of the through hole 34. A nut 36 is caulked and fixed around the mounting hole 35 in the outer side surface of the bottom portion 31 in the axial direction.

  The sensor 29 is held by the sensor holding member 28 by screwing a mounting bolt 55 into the nut 36 and tightening the sensor 29 in a state where the detection portion is inserted through the through hole 34. Further, in this state, the detection portion of the sensor 29 is made to face and oppose the axial inner side surface (outer surface) of the bottom plate portion 22. Thus, the detection unit is opposed to the detection surface of the encoder body 17 through the bottom plate part 22. As a result, when the encoder body 17 rotates together with the hub 3, the S pole and the N pole existing on the detected surface pass alternately in the vicinity of the detection portion of the sensor 29, and the output of the sensor 29 is Therefore, the rotational speed of the wheel fixed to the hub 3 can be obtained. In the case of the conventional structure, since the encoder body 17 is separated from the outside by the cap 20, it is possible to prevent foreign matter from adhering to the detection surface of the encoder body 17. For this reason, the surface to be detected is kept clean, and the reliability of rotation speed detection using the encoder body 17 is ensured.

However, in the case of the conventional structure as described above, there is room for improvement in terms of sufficiently securing the sealing performance by the sealing material 26.
That is, the operation of fixing the sealing material 26 to the outer peripheral surface of the fitting cylinder portion 21 (non-contact cylinder portion 25) constituting the cap 20 is generally performed by vulcanization bonding. The inner mold is inserted on the inner diameter side, and the outer mold is inserted into the fitting tube portion 21 from the inner side in the axial direction and fitted. For this reason, it is difficult to increase the protruding amount of the lip main body 27 from the outer peripheral surface of the fitting cylinder portion 21 because it is necessary to remove (forcibly remove) the outer mold in the axial direction after vulcanization adhesion. Therefore, it is difficult to give the lip body 27 a large fastening allowance for the inner peripheral surface of the outer ring 2, and the sealing performance by the sealing material 26 tends to be lowered.

  Further, as described in, for example, Patent Document 2, in order to prevent damage such as scratches from occurring on the outer peripheral surface of the main body cylindrical portion 24 constituting the fitting cylindrical portion 21, the inner peripheral surface of the outer ring 2 is prevented. Of these, it is conceivable that the inner diameter dimension of the inner portion in the axial direction of the first fitting surface 23 to which the main body cylinder portion 24 is fitted and fixed is made larger than the inner diameter dimension of the first fitting surface 23. ing. If such a configuration is adopted, the outer peripheral surface of the main body cylinder portion 24 is a part of the inner peripheral surface of the outer ring 2 (for example, a joint portion between the grinding surfaces) when the cap 20 is attached (press-fit operation). ), It is possible to prevent damage such as scratches on the outer peripheral surface of the main body cylinder portion 24. However, the tightening allowance of the lip body 27 is further reduced, and there is a possibility that a minute gap is formed between the tip edge of the lip body 27 and the inner peripheral surface of the outer ring 2. When such a minute gap is formed, moisture is easily absorbed by the portion due to the capillary phenomenon, and it becomes difficult to ensure the sealing performance of the sealing material 26.

JP 2013-194461 A International Publication No. 2011/086982

  In view of the circumstances as described above, the present invention provides a rolling bearing with an encoder that can sufficiently ensure a sealing performance between a sealing material provided on an outer peripheral surface of a cap used for separating the encoder from the outside and an inner peripheral surface of an outer ring. It was invented to realize the structure of the unit.

The rolling bearing unit with an encoder of the present invention is used for rotatably supporting a wheel (driven wheel) with respect to a portion that does not rotate even when a knuckle or the like is used, for example, an outer ring, a hub, and a plurality of A rolling element, an encoder, a cap, and a sensor holding member are provided.
Among these, the outer ring has a double row outer ring raceway on the inner peripheral surface, and does not rotate while being supported by a suspension device such as a knuckle during use.
The hub is configured by combining, for example, an inner end of the hub body in the axial direction with an inner ring separate from the hub body, and has a double row of inner ring raceways on the outer peripheral surface. The inner ring is supported concentrically with the outer ring. Further, for example, a rotation-side flange for supporting the wheel is provided in a portion of the outer peripheral surface that protrudes outward in the axial direction from the outer end portion in the axial direction of the outer ring.
Each of the rolling elements is, for example, a ball, a cylindrical roller (including a needle), a tapered roller or a spherical roller, and a plurality of rolling elements are provided in each row between the outer ring raceway and the inner ring raceway. It is provided freely.
The cap is made of a non-magnetic plate and has a bottomed cylindrical shape. The fitting cylinder portion extends in the axial direction, and radially inward from the axial inner end edge of the fitting cylinder portion. And a bottom plate portion extending toward the inner ring, and is fitted and fixed to a portion near the inner end in the axial direction of the outer ring.
Further, the sensor holding member is fitted and fixed on the inner side in the axial direction than the portion of the outer ring where the cap is fitted and fixed, and the detection portion is connected to the detection surface of the encoder via the bottom plate portion. The sensor is held in a state where the is opposed in the axial direction.

In particular, in the case of the rolling bearing unit with an encoder according to the present invention, the fitting cylinder portion is fitted into the first fitting surface formed on the inner circumferential surface of the outer ring near the axial inner end by an interference fit. The main body cylinder part to be fixed and the non-contact cylinder part which is provided on the inner side in the axial direction than the main body cylinder part and does not contact the inner peripheral surface of the outer ring are provided.
An elastic sealing material is fixed to the outer peripheral surface of the non-contact cylindrical portion.
In addition, the sealing material is provided with a lip body (nose gasket) having a substantially trapezoidal cross section or a substantially triangular cross section, for example, and an auxiliary that is provided on the inner side in the axial direction than the lip body and extends outward in the radial direction. It has a lip (radial lip).
Of these, the first fitting surface formed on the tip edge (outer circumferential edge) of the lip main body at a portion of the inner circumferential surface of the outer ring adjacent to the inner side in the axial direction of the first fitting surface. A seal surface having a larger inner diameter than the entire circumference is brought into contact with the entire circumference.
In addition, a part of the auxiliary lip is a portion (for example, a chamfered portion, a stepped portion, an inclined portion) between the seal surface and the second fitting surface on which the sensor holding member is fitted and fixed in the inner peripheral surface of the outer ring. Surface, flat surface, etc.) over the entire circumference.
The shape of the non-contact cylindrical portion is not particularly limited, and the non-contact cylindrical portion can be constituted by, for example, a partial conical cylindrical portion and a cylindrical portion, only a partial conical cylindrical portion, or other shapes. It can comprise from the cylinder part etc. which have.
Further, when the present invention is carried out, the auxiliary lip is extended in a free state in parallel with a virtual plane orthogonal to the central axis of the cap (outward in the radial direction without being inclined in the axial direction). Can only be extended). Then, with the cap attached, the auxiliary lip is elastically inclined in the axial direction, and a part (side surface) of the auxiliary lip is brought into contact with a portion between the seal surface and the second fitting surface. You can make it.
In addition, the radial position of the distal end edge of the auxiliary lip in the free state can be positioned radially outward from the radial position of the distal end edge of the lip body in the free state.
In addition, the inner diameter of the second fitting surface can be made larger than the inner diameter of the seal surface.

When implementing the rolling bearing unit with an encoder of the present invention having the above-described configuration, for example, as in the invention described in claim 2, the tip of the auxiliary lip has a stepped shape, and the auxiliary lip A configuration in which a thin extension portion extending radially outward as compared to the axially outer portion is provided on the axially inner portion of the tip portion can be additionally employed.
Moreover, the structure which makes such a thin extension part contact with a part of said sensor holding member can also be employ | adopted additionally.

According to the rolling bearing unit with an encoder of the present invention having the above-described configuration, it is possible to sufficiently ensure the sealing performance between the sealing material provided on the outer peripheral surface of the cap and the inner peripheral surface of the outer ring.
That is, in the case of the present invention, the sealing material extends not only in a substantially trapezoidal cross-sectional lip body in contact with the sealing surface formed on the inner peripheral surface of the outer ring, but also in a radially outward direction, An auxiliary lip is provided in contact with a portion of the inner peripheral surface of the outer ring between the seal surface and a second fitting surface on which the sensor holding member is fitted and fixed. For this reason, this auxiliary lip can supplement the sealing performance of the lip body. Therefore, according to the present invention, it is possible to sufficiently secure the sealing performance between the sealing material and the inner peripheral surface of the outer ring.

  According to the second aspect of the present invention, a part of the auxiliary lip and a mating surface (a seal surface and a second fitting surface) are formed by the thin extension portion that constitutes the auxiliary lip when the cap is attached. It is possible to cover and protect the contact part with the intermediate part).

Sectional drawing of the rolling bearing unit with an encoder which shows the 1st example of embodiment of this invention. Similarly the upper right part enlarged view of FIG. Similarly, the lower right part (vertical lower end part) enlarged view of FIG. The figure equivalent to FIG. 3 which shows the 2nd example of embodiment of this invention. The figure corresponding to FIG. 3 which shows a 3rd example similarly. Sectional drawing which shows the rolling bearing unit with an encoder of the conventional structure. The A section enlarged view of FIG. 6 similarly.

[First example of embodiment]
A first example of the embodiment of the present invention will be described with reference to FIGS. The feature of the present invention lies in the structure for ensuring the sealing performance between the sealing material 26a provided on the outer peripheral surface of the cap 20a and the inner peripheral surface of the outer ring 2. Also in each example of the other embodiments including this example, the shape in the free state is shown by a solid line as the shape of the sealing material in the drawing, and the shape in the elastically deformed state. Is indicated by a broken line.

The rolling bearing unit with an encoder 1a of this example is a so-called third generation, and supports the hub 3 on the inner diameter side of the outer ring 2 so as to be rotatable via a plurality of rolling elements (balls) 4 and 4. Become. Of these, the outer ring 2 has a stationary flange 6 (see FIG. 6) for supporting and fixing to a knuckle 5 (see FIG. 6) as a suspension device on the outer peripheral surface, and double-row outer ring raceways 7a and 7b on the inner peripheral surface. Are provided. Further, in the case of this example, three cylindrical surfaces (single cylindrical surface) whose inner diameter dimension sequentially increases from the outer side in the axial direction on the inner peripheral surface of the inner end side portion (knuckle pilot portion) of the outer ring 2. The first fitting surface 23a, the seal surface 50, and the second fitting surface 32a are formed. Further, a clearance groove 51 is formed in the inner peripheral surface of the outer ring 2 between the sealing surface 50 and the second fitting surface 32a. The clearance groove 51 and the sealing surface 50 A chamfered portion 52 is formed in the continuous portion. The hub 3 is provided with double row inner ring raceways 8a and 8b and a rotation side flange 9 for supporting and fixing a rotor constituting a wheel and a disc brake on the outer peripheral surface. Further, a plurality of rolling elements 4, 4 are held between the outer ring raceways 7a, 7b and the inner ring raceways 8a, 8b by a plurality of cages 37, 37, respectively, so that they can roll freely. It is provided in the state that was done.
In the example shown in the drawing, balls are used as the rolling elements 4, 4. However, in the case of a rolling bearing unit for an automobile having a heavy weight, tapered rollers may be used as the rolling elements.

  The hub 3 is formed by coupling and fixing a hub body 10 and an inner ring 11. Of these, the hub body 10 has the outer flange on the outer side near the axial end and the flange 9 on the rotation side, and the inner ring raceway 8a on the axially outer side of the inner ring raceways 8a and 8b. Similarly, a small-diameter step portion 12 is provided at a portion near the inner end in the axial direction. The inner ring 11 has an annular shape, and an inner ring raceway 8b on the inner side in the axial direction of the inner ring raceways 8a and 8b is provided on the outer peripheral surface. Such an inner ring 11 is in a state of being fitted and fixed to the small-diameter step portion 12 of the hub main body 10, and a caulking portion 13 in which the axial inner end surface of the inner ring 11 is formed at the axial inner end portion of the hub main body 10. The hub body 10 is coupled and fixed to the hub body 10. Each of the rolling elements 4, 4 and the inner ring 11 is made of high carbon chrome bearing steel such as SUJ2, and is tempered. On the other hand, the hub body 10 is made of medium carbon steel (C: 0.40-0.80% by weight), and the induction hardening process is performed on the outer peripheral surface excluding the caulking part 13. It has been subjected. In addition, when the present embodiment is implemented, an internal thread portion is formed instead of the caulking portion at the inner end portion in the axial direction of the hub, and the inner ring is prevented from coming off by using a nut screwed into the internal thread portion. You can also do things.

  An encoder 15 is fitted and fixed to a shoulder portion 14 provided in the inner half of the inner ring 11 in the axial direction. Thus, the encoder 15 is supported and fixed to the hub 3 concentrically with the hub 3. The encoder 15 includes a support ring 16 that is L-shaped in cross section and has an annular shape as a whole, and an encoder body 17 that is fixed to the support ring 16. Of these, the support ring 16 is made of a magnetic metal plate such as a ferritic stainless steel plate or a cold-rolled steel plate subjected to rust prevention treatment, and is formed by pressing, and is press-fitted into the shoulder portion 14. The support cylinder part 38 and the annular ring part 39 bent at right angles outward in the radial direction from the axial inner end edge of the support cylinder part 38 are provided. The encoder body 17 is fixed to the inner side surface of the annular portion 39 in the axial direction. The encoder body 17 is made of a permanent magnet such as a rubber magnet and is formed in an annular shape. The encoder body 17 is magnetized in the axial direction, and the magnetizing direction is changed alternately and at equal intervals in the circumferential direction. S poles and N poles are alternately arranged at equal intervals on the inner side surface in the axial direction, which is the surface to be detected.

  Further, a seal ring 18 is mounted between the inner peripheral surface of the outer end portion in the axial direction of the outer ring 2 and the outer peripheral surface of the intermediate portion in the axial direction of the hub 3, and the inner portion existing between the two peripheral surfaces. The axially outer side opening of the space 19 is blocked. On the other hand, the axially inner opening of the inner space 19 is closed by a cap (inner cap) 20a. This prevents leakage of grease sealed in the internal space 19 and prevents foreign matter such as muddy water and dust from entering the internal space 19 from the outside.

  The seal ring 18 that closes the axially outer opening of the internal space 19 is supported by the cored bar 40 having an L-shaped cross section that is fitted and fixed to the inner peripheral surface of the axially outer end of the outer ring 2. And an elastic material 41 made of an elastic material such as rubber. The elastic material 41 is provided with a plurality of (three in the illustrated example) lips, and the tip edges of these lips are brought into contact with the outer peripheral surface of the hub 3 over the entire circumference.

  The cap 20a that closes the axially inner opening of the internal space 19 has an austenitic stainless steel plate such as SUS304, an aluminum alloy plate, a synthetic resin plate so as not to adversely affect the detection performance of the sensor 29 for detecting the rotational speed. Etc., and is made of a non-magnetic plate, and the plate thickness is constant. The cap 20a has a bottomed cylindrical shape (substantially U-shaped cross section) as a whole, a fitting cylinder part 21a extending in the axial direction, and a radial direction from an axial inner end edge of the fitting cylinder part 21a. And a bottom plate portion 22a extending inward. Among these, the fitting cylinder part 21a is provided in the main body cylinder part 24a provided in the axially outer half part and in the axially inner half part, and the inner peripheral surface of the outer ring 2 in the mounted state of the cap 20a. It is comprised from the non-contact cylinder part 25a which does not contact. Of these, the main body cylinder portion 24a is formed in a single cylindrical shape whose outer diameter dimension does not change in the axial direction, and is a cylindrical surface shape formed on the inner peripheral surface of the outer ring 2 near the inner end in the axial direction. The first fitting surface 23a is internally fitted and fixed by interference fitting. On the other hand, the non-contact cylindrical portion 25a is provided in a state of being continuous with the axially inner end edge of the main body cylindrical portion 24a, and is a partial conical cylindrical portion that is inclined in a direction toward the radially inward as it goes inward in the axial direction. 42 and a small-diameter cylindrical portion 43 which is provided in a state of being continuous with the partial conical cylinder portion 42 and whose outer diameter dimension does not change in the axial direction. The axial dimension of the non-contact cylindrical portion 25a is at least twice, preferably at least three times the thickness dimension of the plate material constituting the cap 20a. Thereby, when the fitting tube portion 21a is fitted and fixed to the first fitting surface 23a by an interference fit, the radially inward force applied to the fitting tube portion 21a is applied to the non-contact tube. By consuming the deformation of the portion 25a, it is possible to effectively prevent the axial deformation of the bottom plate portion 22a (especially an outer diameter side flat plate portion 44 described later).

  The bottom plate portion 22a is formed in a disc shape as a whole, and in order from the outer diameter side, an outer diameter side flat plate portion 44, a cylindrical portion 45, an intermediate flat plate portion 46, and an inclined plate portion 47, The central flat plate portion 48 is provided. The outer diameter side flat plate portion 44 is provided in a state of being bent radially inward from the axial inner end edge of the non-contact cylindrical portion 25a (small diameter cylindrical portion 43). It is provided in a portion that is in close proximity to the detection surface. The cylindrical portion 45 is cylindrical and is provided in a state of being bent inward in the axial direction from the radially inner end edge of the outer diameter side flat plate portion 44 so as to cover the caulking portion 13. The intermediate flat plate portion 46 has an annular shape and is provided in a state of being bent radially inward from the axial inner end edge of the cylindrical portion 45. The inclined plate portion 47 is inclined in the radially inward direction as it goes outward in the axial direction, and is a portion between the inner peripheral edge of the intermediate flat plate portion 46 and the outer peripheral edge of the central flat plate portion 48. Is provided. Further, the central flat plate portion 48 has a circular plate shape and is provided in a state of being bent radially inward from the axial outer end edge of the inclined plate portion 47.

  In the case of this example, on the outer peripheral surface of the non-contact cylindrical portion 25a constituting the fitting cylindrical portion 21a, acrylonitrile butadiene rubber (NBR), hydrogenated acrylonitrile butadiene rubber (HNBR), ethylene propylene rubber (EPDM), poly A sealing material 26a made of an elastic material such as acrylic rubber (ACM), fluorine rubber (FKM), silicon rubber or the like is fixed by vulcanization adhesion. The sealing material 26a includes a lip body (nose gasket) 27a and an auxiliary lip (radial lip) which have a larger outer diameter than the outer diameter of the fitting cylinder 21a (main cylinder 24a) in a free state. 49) is provided in a state of being continuous with the seal base fixed to the outer peripheral surface of the non-contact cylindrical portion 25a. Of these, the lip main body 27a has a substantially trapezoidal cross section in which the thickness dimension in the axial direction decreases from the proximal end portion toward the distal end portion, and is provided in the axially outer portion of the sealing material 26a. In the state where the cap 20 a is fitted and fixed to the outer ring 2, the tip edge (outer circumferential edge) of the lip body 27 a is positioned in the axial direction of the first fitting surface 23 a among the inner circumferential surface of the outer ring 2. The cylindrical seal surface 50 having a larger inner diameter than that of the first fitting surface 23 formed in a portion adjacent to the inside is brought into contact with the entire circumference in a state having a tightening allowance. The auxiliary lip 49 has a constant thickness dimension from the base end portion to the tip end portion, and extends in a free state in parallel with a virtual plane orthogonal to the central axis of the cap 20a (not inclined in the axial direction). It extends only outward in the radial direction. Further, in the free state of the sealing material 26a, the radial position of the tip edge of the auxiliary lip 49 is positioned radially outward from the radial position of the tip edge of the lip body 27a. Then, in a state where the cap 20 a is fitted and fixed to the outer ring 2, the radially outer end portion of the auxiliary lip 49 on the outer side in the axial direction is opposed to the chamfered portion 52 formed on the inner peripheral surface of the outer ring 2. It is in contact with the entire circumference. Further, in this state, the auxiliary lip 49 starts from a constricted portion provided at a continuous portion of the base end portion of the auxiliary lip 49 and the seal base, and goes inward in the axial direction as it goes outward in the radial direction. Inclined elastically in the direction. The chamfered portion 52 is a cylindrical second fitting surface 32a for fitting and fixing the seal surface 50 that contacts the lip main body 27a and the sensor holding member 28a to be described later, of the inner peripheral surface of the outer ring 2. More specifically, a portion between the sealing surface 50 and the clearance groove 51 provided on the outer side in the axial direction of the second fitting surface 32a. The shape is a partially conical cylindrical surface that is inclined in a direction in which the inner diameter dimension increases as it goes inward in the axial direction.

  Also in the case of this example, a sensor holding member (outer cap) 28a is provided on the inner side in the axial direction of the cap 20a having the above-described configuration. The sensor holding member 28a is used to hold the sensor 29 for detecting the rotation speed, and is axially more than the portion of the inner peripheral surface of the outer ring 2 where the cap 20a is fitted and fixed. Internally fitted and fixed. The sensor holding member 28a is formed by, for example, pressing a cold-rolled steel sheet that has been subjected to rust prevention treatment, and has a bottomed cylindrical shape (substantially U-shaped cross section), and extends in the axial direction. A cylindrical portion 30a, and a bottom portion 31a extending radially inward from the axial inner end edge of the cylindrical portion 30a. The sensor holding member 28a having such a configuration is a cylinder formed on the inner peripheral surface of the axially inner end portion of the outer ring 2 with the axially outer half portion of the cylindrical portion 30a being mounted on the outer ring 2. While the inner fitting is fixed to the planar second fitting surface 32a by interference fitting, the outer side surface of the outer ring 2 is formed on the axially outer surface of the outward flange portion (bent portion) 33a formed at the axially intermediate portion of the cylindrical portion 30a. It is abutted against the inner end face in the axial direction. A through hole 34a is formed in a portion of the bottom portion 31a that faces the detected surface of the encoder body 17 in the axial direction, and the detection portion of the sensor 29 is inserted into the through hole 34a. Yes. A mounting hole 35a is formed in the bottom portion 31a in the radially inner portion of the through hole 34a. And the nut 36a is caulked and fixed to the peripheral part of this attachment hole 35a among the axial direction outer surfaces of this bottom part 31a. Further, in the axially inner half portion of the cylindrical portion 30a, in the state where the rolling bearing unit with encoder 1a is assembled to the vehicle body, a drain hole 53 penetrating in the radial direction is formed in a portion positioned vertically downward. One or more are formed.

  The sensor 29 is held by the sensor holding member 28a by screwing the mounting bolt 55 into the nut 36a and tightening it with the detecting portion inserted through the through hole 34a. Further, in this state, the detection portion of the sensor 29 is brought close to or in contact with the axial inner side surface (outer surface) of the outer diameter side flat plate portion 44 constituting the bottom plate portion 22a. Thereby, this detection part is made to oppose the to-be-detected surface of the said encoder main body 17 through this outer diameter side flat plate part 44. FIG. As a result, also in the case of this example, when the encoder body 17 rotates together with the hub 3, the S pole and the N pole existing on the detected surface pass alternately in the vicinity of the detection portion of the sensor 29. Since the output of the sensor 29 changes, the rotational speed of the wheel fixed to the hub 3 can be obtained.

In particular, in the case of the structure of this example, it is possible to sufficiently ensure the sealing performance between the sealing material 26 a provided on the outer peripheral surface of the cap 20 a and the inner peripheral surface of the outer ring 2.
That is, in the case of the present example, not only the lip body 27a having a substantially trapezoidal cross section in contact with the sealing surface 50 formed on the inner peripheral surface of the outer ring 2 but also outward in the radial direction. The auxiliary lip 49 that extends over and contacts the chamfered portion 52 formed in the inner peripheral surface of the outer ring 2 between the seal surface 50 and the second fitting surface 32a. Is provided. For this reason, the auxiliary lip 49 can supplement the sealing performance of the lip body 27a. More specifically, as shown in FIG. 3, in the state where the cap 20a is fitted and fixed to a portion near the inner end in the axial direction of the outer ring 2, the auxiliary lip 49 is pivoted outward in the radial direction. Inclined elastically in the direction toward the inner side (configured in a partially conical cylinder shape). Therefore, even when muddy water or the like enters the inside of the sensor holding member 28a, the muddy water flows down along the inner side surface (outer surface) in the axial direction of the bottom plate portion 22a constituting the cap 20a. Along the axially inner side surface of the auxiliary lip 49, the auxiliary lip 49 is guided radially outward from the contact portion between the tip edge of the lip body 27 a and the seal surface 50. And it becomes possible to discharge muddy water to the outside through the drain hole 53 formed in the cylindrical portion 30a constituting the sensor holding member 28a. Thus, according to the rolling bearing unit with an encoder 1a of this example, a sufficient sealing performance between the sealing material 26a and the inner peripheral surface of the outer ring 2 can be secured.

  In addition, in the case of this example, since the inner diameter dimension of the seal surface 50 and the second fitting surface 32a is larger than the inner diameter dimension of the first fitting surface 23a, when the cap 20a is press-fitted. Further, it is possible to prevent a long scratch in the axial direction on the outer peripheral surface of the main body cylinder portion 24a. Therefore, it is possible to prevent foreign matter from entering the internal space 19 through the scratches generated in this way.

[Second Example of Embodiment]
A second example of the embodiment of the present invention will be described with reference to FIG. In the case of this example, the shape of the tip of the auxiliary lip 49a constituting the sealing material 26b is different from that of the first example of the above-described embodiment. That is, in the case of this example, the tip of the auxiliary lip 49a has a stepped shape, and the tip of the tip of the auxiliary lip 49a has an inner half in the axial direction and radially outward compared to the outer half in the axial direction. An extended thin extension 54 is provided. As shown in FIG. 4, such a thin extension portion 54 covers the chamfered portion 52 so as to cover the contact portion with the axially outer side surface of the auxiliary lip 49 a in contact with the chamfered portion 52. It becomes a curved shape (curved) in a direction approaching. Therefore, the portion of the auxiliary lip 49a that contacts the chamfered portion 52 can be effectively protected from foreign matter such as muddy water.
Other configurations and operational effects are the same as those in the first example of the embodiment.

[Third example of embodiment]
A third example of the embodiment of the present invention will be described with reference to FIG. In the case of this example, the seal material 26b provided with the auxiliary lip 49a similar to the second example of the above-described embodiment is used, but the thin extension 54 constituting the seal material 26b is attached to the sensor. It is made to contact a part of member 28b. That is, in the case of this example, a bent portion 55 is formed at the outer end in the axial direction of the cylindrical portion 30b that constitutes the sensor holding member 28b. The distal end edge (outer peripheral edge) of the thin extension 54 is brought into contact with the inner peripheral surface of the bent portion 55 over the entire periphery. Specifically, when the sensor holding member 28b is fitted and fixed to the inner end portion in the axial direction of the outer ring 2, the thin extension portion 54 is elastically deformed outward in the axial direction by the bent portion 55, and this thin wall By elastically restoring the extension portion 54, the tip edge of the thin extension portion 54 is brought into contact with the inner peripheral surface of the bent portion 55.

In the case of this example having the above-described configuration, the outer ring 2 is provided in a portion adjacent to the outer side in the axial direction of the second fitting surface 32a for fitting and fixing the cylindrical portion 30b. It is possible to effectively prevent foreign matter such as muddy water from accumulating in the escape recess 51. Accordingly, it is possible to effectively prevent the sensor holding member 28b from being rusted, and to effectively prevent the fitting holding force of the sensor holding member 28b from being lowered over a long period of time.
About another structure and an effect, it is the same as that of the case of the 1st example and 2nd example of embodiment mentioned above.

  The present invention can also be implemented by a rolling bearing unit with an encoder, in which a hub body and an inner ring are coupled and fixed by a nut. Further, when the present invention is carried out, the shape of the cap and the sensor holding member and the sensor holding structure (support structure) with respect to the sensor holding member are not limited to the structure of each example of the above-described embodiment. Changes and selections can be made as long as the gist is not changed.

DESCRIPTION OF SYMBOLS 1, 1a Rolling bearing unit for wheel support 2 Outer ring 3 Hub 4 Rolling body 5 Knuckle 6 Static side flange 7a, 7b Outer ring raceway 8a, 8b Inner ring raceway 9 Rotating side flange 10 Hub body 11 Inner ring 12 Small diameter step part 13 Caulking part 14 Shoulder Part 15 Encoder 16 Support ring 17 Encoder body 18 Seal ring 19 Internal space 20, 20a Cap (inner cap)
21, 21a Fitting cylinder part 22, 22a Bottom plate part 23, 23a First fitting surface 24, 24a Body cylinder part 25, 25a Non-contact cylinder part 26, 26a, 26b Sealing material 27, 27a Lip body 28, 28a, 28b Sensor holding member (outer cap)
29 Sensor 30, 30a, 30b Cylindrical part 31, 31a Bottom part 32, 32a Second fitting surface 33, 33a Outward flange part 34, 34a Through hole 35, 35a Mounting hole 36, 36a Nut 37 Cage 38 Supporting cylinder part 39 yen Ring part 40 Metal core 41 Elastic material 42 Partial conical cylinder part 43 Small diameter cylindrical part 44 Outer diameter side flat plate part 45 Cylindrical part 46 Intermediate flat plate part 47 Inclined plate part 48 Central flat plate part 49, 49a Auxiliary lip 50 Seal surface 51 Relief Groove 52 Chamfer 53 Water drain hole
54 Thin extension 55 Mounting bolt

Claims (2)

An outer ring having a double-row outer ring raceway on the inner peripheral surface and not rotating during use;
A hub having a double-row inner ring raceway on the outer peripheral surface and supported concentrically with the outer ring on the inner diameter side of the outer ring;
Between the both outer ring raceways and the both inner ring raceways, a plurality of rolling elements provided so as to be freely rollable in both rows,
An annular encoder that is formed by alternately changing the magnetic properties of the inner surface in the axial direction with respect to the circumferential direction, and is supported concentrically with the hub at the inner end in the axial direction of the hub;
A fitting cylinder portion extending in the axial direction; and a bottom plate portion extending radially inward from an inner edge in the axial direction of the fitting cylinder portion; A non-magnetic plate-made bottomed cylindrical cap that is fitted and fixed,
A sensor in which the cap is fitted and fixed inward in the axial direction with respect to the portion where the cap is fitted and fixed in the outer ring, and the detection portion is opposed to the detection surface of the encoder in the axial direction through the bottom plate portion. A sensor holding member for holding
A rolling bearing unit with an encoder comprising:
A main body cylinder portion in which the fitting cylinder portion is fitted and fixed by an interference fit to a first fitting surface formed on an inner peripheral surface of the outer ring in the axial direction inner end portion, than the main body cylinder portion. A non-contact cylindrical portion that is provided on the inner side in the axial direction and does not contact the inner peripheral surface of the outer ring,
A sealing material made of an elastic material is fixed to the outer peripheral surface of the non-contact cylindrical portion,
This sealing material has a lip body and an auxiliary lip that is provided on the inner side in the axial direction than the lip body and extends outward in the radial direction. Out of the inner peripheral surface of the outer ring, contact is made over the entire circumference with a seal surface having a larger inner diameter than the first fitting surface formed in a portion adjacent to the inner side in the axial direction of the first fitting surface. A portion of the auxiliary lip is brought into contact with the entire circumference of the inner circumferential surface of the outer ring between the seal surface and the second fitting surface on which the sensor holding member is fitted and fixed. Yes,
Rolling bearing unit with encoder characterized by this.   The tip of the auxiliary lip has a stepped shape, and a thin-walled extension that extends radially outward compared to the axially outer portion is provided at the axially inner portion of the tip of the auxiliary lip. The rolling bearing unit with an encoder according to claim 1.

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