JP2015064089A - Wheel support bearing unit with encoder - Google Patents

Abstract

[PROBLEMS] To prevent moisture from entering the inside of a bearing from a fitting surface between a slinger and an inner ring without increasing the manufacturing cost and shape (size) of the pack seal, and maintain the bearing performance over a long period of time. Provided is a wheel supporting bearing unit with an encoder that can be used. A slinger 16 includes a rotation-side cylindrical portion 18 that is fitted and fixed to an outer peripheral surface of an axially inner end portion of a hub 3 by an interference fit, and an outer ring 2 from an axially inner end edge of the rotation-side cylindrical portion 18. And an encoder 25a that is supported and fixed on the inner side surface in the axial direction of the rotation-side annular portion 19 includes an inner-diameter lip 26 that extends from the inner-diameter side thereof. In an inverted state in the axial direction, the hub 3 is in contact with the outer peripheral surface of the hub 3 with a tightening margin. [Selection] Figure 1

Description

  The present invention relates to a wheel support bearing unit for rotatably supporting a wheel of an automobile with respect to a suspension device.

  2. Description of the Related Art Conventionally, a wheel support bearing unit in which a rolling bearing such as a ball bearing or a tapered roller bearing is incorporated in a wheel rotation support portion is known. And, in order to control the anti-lock brake system (ABS) and the traction control system (TCS), a sealing device in which a magnetic encoder for detecting the rotational speed of the wheel is integrated is incorporated into the wheel support bearing unit. A wheel support bearing unit with an encoder is also known. FIG. 5 shows an example of a wheel support bearing unit with an encoder provided with such a sealing device with an encoder.

  In the wheel support bearing unit 1 with an encoder shown in FIG. 5, an outer ring 2 that is a stationary side race and a hub 3 that is a rotation side race are arranged concentrically with each other. And the double-row outer ring raceways 4 and 4 each provided on the inner peripheral surface of the outer ring 2 are stationary side tracks, and the double-row inner ring raceway each provided on the outer peripheral surface of the hub 3 and each being a rotary side track. A plurality of balls 6 and 6, each of which is a rolling element, are arranged between each of the rows 5 and 5. The balls 6 and 6 are held by the cages 7 and 7 so as to be able to roll.

  With such a configuration, the hub 3 is rotatably supported on the inner diameter side of the outer ring 2. In order to rotatably support the wheel and the like with respect to the suspension device, the stationary flange 8 provided on the outer peripheral surface of the outer ring 2 is screwed and fixed to the suspension device (not shown), and the outside of the hub 3 in the axial direction. A braking rotary body such as a wheel and a disk rotor is screwed and fixed to a rotation side flange 9 formed on the outer peripheral surface of the end. Note that “outside in the axial direction” means the left side of each figure, which is the outside in the width direction of the vehicle when assembled to the vehicle. On the other hand, the right side of each figure, which is the inner side in the width direction of the vehicle, is referred to as the inner side in the axial direction.

  Between the inner peripheral surface of the outer ring 2 and the outer peripheral surface of the hub 3, both end openings of the bearing internal space 10 in which the balls 6 and 6 are installed are respectively formed by a seal ring 11 and a combination seal ring 12 which are sealing devices. The entire circumference is closed. A seal ring 11 that closes the axially outer end side opening of the bearing internal space 10 is configured by reinforcing an elastomer sealing material 14 such as rubber with a metal core 13 made of a metal plate to form an annular shape as a whole. . The sealing material 14 has a plurality (three in the illustrated example) of sealing lips 15a, 15b, and 15c. Then, in a state where the metal core 13 is fitted into the outer circumferential end portion of the inner peripheral surface of the outer ring 2 with an interference fit, the tip edges of the seal lips 15a to 15c are connected to the inner side surface in the axial direction of the rotary flange 9 or the hub 3. Are respectively slidably contacted with the outer peripheral surface of the intermediate portion.

  The combination seal ring 12 is formed by combining a slinger 16 and a seal ring 17. The slinger 16 is formed by bending a metal plate and is formed into an annular shape with an L-shaped cross section. The slinger 16 is radially outward from the rotation-side cylindrical portion 18 and the axial inner end edge of the rotation-side cylindrical portion 18. And a rotation-side annular ring portion 19 that is bent in a circle. Such a slinger 16 is fixed to the hub 3 by fitting the rotation-side cylindrical portion 18 to the hub 3 (the inner ring that constitutes the hub 3 together with the hub body) with an interference fit. ing.

  The seal ring 17 includes a metal core 20 made of a metal plate and a seal material 21. The sealing material 21 includes a plurality of (three in the illustrated example) sealing lips 22a, 22b, and 22c. The cored bar 20 is formed by bending a metal plate to have a substantially L-shaped cross section, and the whole is formed in an annular shape. The stationary side cylindrical part 23 and the axially outer end edge of the stationary side cylindrical part 23 are arranged in the radial direction. It consists of a stationary-side circular ring portion 24 bent inward. The seal ring 17 provided with such a cored bar 20 is fixed to the outer ring 2 by fitting the stationary-side cylindrical portion 23 into the inner end of the outer ring 2 in the axial direction by an interference fit. Further, in this state, the tip edge of the seal lip 22a is on the outer side surface in the axial direction of the rotation-side annular ring portion 19, and the tip edge of each seal lip 22b, 22c is on the outer peripheral surface of the rotation-side cylindrical portion 18, respectively. It is in contact with slid.

  An annular encoder 25 is vulcanized over the entire circumference on the inner surface in the axial direction of the rotating-side annular portion 19 constituting the slinger 16. The encoder 25 is made of a permanent magnet such as a rubber magnet or a plastic magnet in which a magnetic powder is dispersed in a polymer material such as rubber or synthetic resin to form a ring shape as a whole, and is magnetized in the axial direction. The magnetization direction is changed alternately and at equal intervals in the circumferential direction. Therefore, the south pole and the north pole are alternately arranged at equal intervals in the circumferential direction on the inner side surface of the encoder 25 in the axial direction, which is the detected surface. The detection surface of the rotation detection sensor (not shown) is opposed to the detection surface of such an encoder 25 so that the rotation speed of the wheel rotating together with the hub 3 can be measured.

  In the case of the conventional wheel support bearing unit 1 with the encoder structure as described above, the bearing inner space 10 is filled with muddy water by closing both axial ends of the bearing inner space 10 with the seal ring 11 and the combined seal ring 12. And the like, and the grease enclosed in the bearing internal space 10 is prevented from leaking to the outside. Further, when the slinger 16 fitted and fixed to the hub 3 rotates with the rotation of the wheel, the output of a sensor (not shown) opposed to the encoder 25 that rotates with the slinger 16 changes. The frequency at which the output of this sensor changes is proportional to the rotational speed of the wheel. Therefore, if the output signal of the sensor is input to a controller (not shown), the rotational speed of the wheel can be obtained and the ABS and TCS can be controlled appropriately.

  However, the combination seal ring 12 having the conventional structure as shown in FIG. 5 still has room for improvement from the viewpoint of further improving the sealing performance. That is, as described above, the rotating side cylindrical portion 18 constituting the slinger 16 is externally fitted and fixed to the inner end portion in the axial direction of the hub 3. However, the hub 3 made of a bearing material and the slinger 16 made of a steel plate are metal fittings, and avoid the presence of minute gaps on the fitting surface, such as scratches generated when the slinger 16 is press-fitted into the hub 3. It is difficult to do. For this reason, there is a possibility that moisture may enter the bearing internal space 10 from this fitting surface, and it is necessary to improve the sealing performance.

  As a prior art for improving this part, a lip is provided on the inner diameter side of the encoder attached to the slinger, and this lip is elastically brought into contact with the outer peripheral surface of the shaft (inner ring), thereby sealing the fitting part. Patent Document 1 discloses a pack seal with an encoder that improves the above.

JP 2007-052036 A

  However, the magnetic rubber forming the encoder is a mixture of 80 to 90 wt% magnetic material powder such as ferrite and the remaining 10 to 20 wt% rubber material (NRB (nitrile rubber) or ACM (acrylic rubber)). Therefore, it is a brittle material that is inferior in elongation and elasticity compared to general rubber. Therefore, it is difficult to form an undercut by so-called forced removal at the time of vulcanization molding, and the magnetic rubber lip provided on the inner diameter portion of the encoder is sufficient to prevent water immersion as in Patent Document 1. There is a problem that it is difficult to give tension (rubber elasticity and tightening allowance).

  In view of the above circumstances, the present invention allows moisture to enter the bearing internal space from the fitting surface between the slinger and the hub (inner ring) without increasing the manufacturing cost and shape (size) of the combined seal ring. It is an object of the present invention to provide a bearing unit for supporting a wheel with an encoder that can prevent this from occurring and maintain the bearing performance over a long period of time.

A wheel support bearing unit with an encoder according to the present invention includes a rotation-side bearing ring having a rotation-side track by forming a rotation-side flange for mounting a wheel, a stationary-side raceway having a stationary-side track, and the rotation-side track, A plurality of rolling elements provided between the stationary side raceway and the stationary side raceway so as to be able to roll, and the interior of the bearing existing between the mutually facing peripheral surfaces of the rotation side raceway ring and the stationary side raceway ring And a combination seal ring composed of a seal ring and a slinger for closing the end opening of the space. The slinger has an L-shaped metal plate and is formed in an annular shape as a whole, a rotation-side cylindrical portion that is fitted and fixed to the peripheral surface of the rotation-side raceway, and an axially inner end green of the rotation-side cylinder portion. An encoder that is a permanent magnet with a S-pole and an N-pole alternately magnetized in the circumferential direction, and a rotating-side annular portion bent toward the peripheral surface of the stationary-side raceway. It is supported and fixed on the inner side surface in the axial direction of the rotating-side circular ring portion.
In particular, in the wheel support bearing unit with an encoder according to the present invention, the lip extending from the rotation side raceway side of the encoder is reversed in the axial direction on the circumferential surface of the rotation side raceway. Abutting with tightening allowance.

  Further, in the wheel support bearing unit with an encoder of the present invention, the lip protrudes inward in the axial direction from the encoder in a free state, and is pressed by a press-fitting jig for press-fitting the slinger into the rotating raceway. Then, it is reversed and is in contact with the peripheral surface of the rotating side race.

According to the present invention, without increasing the manufacturing cost and shape (size) of the combined seal ring, moisture can be prevented from entering the bearing from the fitting surface between the slinger and the hub, and the bearing performance can be extended for a long time. You can crawl and maintain.
That is, in the case of the wheel support bearing unit with an encoder according to the present invention, the inner diameter lip extending from the inner diameter side of the encoder has a tightening margin over the entire circumference of the circumferential surface of the rotating side raceway (hub). And abut. Therefore, the mating surface between the slinger and the rotating raceway is sealed by the inner diameter lip of the encoder, and external muddy water does not reach the mating surface, so that moisture can enter the bearing internal space through the mating surface. Can be prevented.
Further, since the inner diameter lip is formed by vulcanization molding of the conventional encoder and the inner diameter lip is inverted and pushed in by the conventional slinger press-fitting process, no new manufacturing process is required, and the manufacturing cost does not increase. The seal ring and slinger of the combined seal ring can use the same structure as the conventional one, and there is no need to change the shape (size).

The fragmentary sectional view of the combination seal ring which shows 1st Embodiment. Explanatory drawing of the internal diameter lip press fit in 1st Embodiment. The fragmentary sectional view of the combination seal ring which shows 2nd Embodiment. Explanatory drawing of the internal diameter lip press fit in 2nd Embodiment. Sectional drawing of the roller bearing unit for wheel support with an encoder of the conventional structure.

[First Embodiment]
FIG. 1 shows a first embodiment of the present invention. The combination seal ring 12a constituting the wheel support bearing unit with an encoder of the present embodiment includes a hub 3 that is a rotating side race ring and a outer ring 2 that is a stationary side race ring, which rotate relative to each other, as shown in FIG. Is installed between the outer peripheral surface of the hub 3 and the inner peripheral surface of the outer ring 2 to close the axial inner end opening of the bearing internal space 10. Regarding the structure, operation, and effect of the portion other than the combined seal ring 12a including the seal ring 11 that closes the axially outer end opening of the bearing internal space 10, the conventional wheel with an encoder shown in FIG. The same as in the case of the supporting bearing unit. For this reason, illustration and description of overlapping portions are omitted or simplified, and the following description will be focused on the combination seal ring 12a.

The combination seal ring 12a of this embodiment includes a seal ring 17, a slinger 16, and an encoder 25a. The seal ring 17 includes a core metal 20 and a seal material 21. The metal core 20 is formed by bending a metal plate such as a mild steel plate to form an annular shape as a whole with a substantially L-shaped cross section, and is fitted into the inner peripheral surface of the axially inner end of the outer ring 2 by an interference fit. The stationary side cylindrical portion 23 to be fixed, and the stationary side circular ring portion 24 bent radially inward from the axial outer end edge of the stationary side cylindrical portion 23 toward the outer peripheral surface of the hub 3. Yes.
The seal material 21 is made of an elastic material such as an elastomer such as rubber, and has three seal lips 22a, 22b, and 22c each having a base end portion vulcanized and formed over the entire circumference. doing. A gasket 29 is formed by covering the outer peripheral surface of the portion near the inner end in the axial direction of the stationary-side cylindrical portion 23 over the entire periphery with the sealing material 21. By elastically fitting the gasket 29 to the inner peripheral surface of the outer ring 2, the fitting surface between the stationary side cylindrical portion 23 and the outer ring 2, which is a metal-to-metal fitting, is sealed.

  The slinger 16 is formed by bending a metal plate made of a magnetic material such as martensitic stainless steel to form an entire ring shape with an L-shaped cross section. The outer peripheral surface of the axially inner end of the hub 3 (inner ring) A rotation-side cylindrical portion 18 that is externally fixed by an interference fit, and a rotation-side circular ring that is bent radially outward from the axial inner end edge of the rotation-side cylindrical portion 18 toward the inner peripheral surface of the outer ring 2. Part 19. The three seal lips 22 a to 22 c are brought into sliding contact with the outer peripheral surface of the rotation-side cylindrical portion 18 and the axially outer surface of the rotation-side annular ring portion 19.

The encoder 25a is formed of a magnetic rubber in which ferrite powder is mixed in rubber in a ring shape, and is magnetized in the axial direction. The magnetization direction is changed alternately and at equal intervals over the circumferential direction. Therefore, on the side surface in the axial direction of the encoder 25a, the S pole and the N pole are alternately arranged at equal intervals over the circumferential direction. The encoder 25a is bonded and fixed to the inner side surface in the axial direction of the rotation-side annular ring portion 19 by vulcanization molding.
In the case of the present embodiment, the inner diameter lip 26 extending from the inner diameter side of the encoder 25a is in contact with the entire surface of the hub 3 with a tightening margin while being reversed in the axial direction. Thereby, the fitting surface of the rotation side cylindrical part 18 and the hub 3 which are fitting of metals is sealed.

  FIG. 2 is an explanatory view of the process of press-fitting the combined seal ring 12a into the outer ring 2 and the hub 3 by the press-fitting jig 30 in order to seal the metal-to-metal fitting surface of the hub 3 and the rotation side cylindrical portion 18. The inner lip 26 is shown in a free state. The inner diameter lip 26 is formed so as to extend from the inner diameter end of the encoder 25a toward the inner side in the axial direction to a position protruding further inward in the axial direction than the inner surface in the axial direction, which is the detection surface of the encoder 25a. With such a shape, the inner diameter lip 26 can be vulcanized without undercut (unreasonable removal during vulcanization molding). Further, by thinning the portion between the inner lip 26 and the detected surface of the encoder 25a in the radial direction, the inner lip 26 can be easily deformed, and the deformation of the inner lip 26 affects the detected surface. It is restrained to do.

  The press-fitting jig 30 presses the outer ring contact portion 31 that determines the press-fitting position of the combined seal ring 12a by contacting the inner end surface in the axial direction of the outer ring 2, the inner end surface (gasket 29) in the axial direction of the seal ring 17 and the encoder 25a. The pressing portion 32 is press-fitted into a predetermined position, and the outer ring contact portion 31 and the protruding portion 33 that protrudes outward in the axial direction from the pressing portion 32 and contacts the inner diameter lip 26. With such a press-fitting jig 30, when the combined seal ring 12a is press-fitted until the outer ring abutting portion 31 abuts on the inner end surface of the outer ring 2 in the axial direction, the inner diameter lip 26 is pressed against the projecting portion 33, whereby the encoder It is pushed between 25a and the hub 3. At this time, the inner diameter lip 26 is reversed in the axial direction and is sandwiched between the encoder 25a and the hub 3, and the tip edge of the inner diameter lip 26 is placed over the entire circumference so as to contact the outer peripheral surface of the hub 3. Configure. In the inverted state, the inner diameter lip 26 is folded back outward in the axial direction, the tip edge portion of the inner diameter lip 26 is positioned on the outer side in the axial direction (inside the bearing) than the free state, and the tip edge is the hub 3. The state which contacted the outer peripheral surface.

In the case of the present embodiment having the above-described configuration, moisture is transferred from the fitting surface between the slinger 16 and the hub 3 without increasing the manufacturing cost and shape (size) of the combined seal ring 12a. 10 can be prevented and the bearing performance can be maintained for a long time.
That is, an inner diameter lip 26 that extends inward in the axial direction is formed at the inner diameter end of the encoder 25a, and the inner diameter lip 26 is reversed and abuts on the outer peripheral surface of the hub 3 with a tightening margin on the entire circumference. I am letting. Accordingly, since the outer muddy water is sealed by the inner diameter lip 26 in contact with the hub 3 and does not reach the fitting surface between the slinger 16 and the metal of the hub 3, the moisture enters the bearing internal space 10 through the fitting surface. There is no invasion.

  Further, the inner diameter lip 26 is formed of the same material as that of the encoder 25a by extending the inner diameter portion of the encoder 25a, and has no undercut portion. Since there is no need to add, the manufacturing cost does not increase. The seal ring 17 and the slinger 16 of the combination seal ring 12a can use the same structure as the conventional one, and there is no need to change the shape (size) or change the design. Further, the process of press-fitting the combined seal ring 12a into the outer ring 2 and the hub 3 is the same as the conventional process.

Furthermore, compared with the lip of Patent Document 1 described above, the inner diameter lip 26 provided at the inner diameter portion of the encoder 25a can be given a tightening force (rubber elasticity and tightening allowance) sufficient to prevent water immersion. That is, in the inner diameter lip 26, the force for restoring the inverted state is applied to the compression force as a force in the compression direction, and the same effect as when the compression force is substantially increased is obtained. The sealing performance of the fitting surface between the hub 3 and the slinger 16 can be further improved.
In addition, since the shape of the inner diameter lip 26 of the present embodiment can be vulcanized without undercut, it can be applied to magnetic rubber containing a large amount of magnetic material (high magnetic flux density) contained in the encoder 25a. . Also, rubber materials such as acrylic rubber (ACM), fluorine rubber (FKM), and silicon rubber (VMQ) that have a slow vulcanization speed, low strength immediately after vulcanization, and need secondary vulcanization It can also be applied to magnetic rubber. Other configurations, operations and effects are the same as those of the conventional structure described above.

[Second Embodiment]
FIG. 3 shows a second embodiment of the present invention. In the case of the combination seal ring 12b of this embodiment, the shape of the inner diameter lip 26a formed on the inner diameter portion of the encoder 25b is different from that of the first embodiment described above. That is, the inner diameter lip 26a extending inward in the axial direction from the inner diameter end of the encoder 25b has a tip portion branched into a Y-shaped cross section, and an outer lip 27 positioned on the inner side in the axial direction (outer bearing side); The inner lip 28 is located on the outer side in the axial direction (bearing inner side). Then, the outer lip 27 (see FIG. 4) in the free state protrudes inward in the axial direction from the inner side surface in the axial direction, which is the detected surface of the encoder 25b. Such an inner diameter lip 26a has the outer lip 27 and the inner lip 28 in contact with the outer peripheral surface of the hub 3 over the entire surface with a tightening margin in a state of being inverted in the axial direction. Thereby, the fitting surface of the rotation side cylindrical part 18 and the hub 3 which are fitting of metals is sealed.

FIG. 4 is an explanatory diagram of a process of press-fitting the combination seal ring 12b into the outer ring 2 and the hub 3 by the press-fitting jig 30a. The tip of the inner diameter lip 26a has a Y-shaped cross section, and the pushing amount of the inner diameter lip 26a can be reduced. Therefore, the protrusion 33 in FIG. It can be pressed.
The inner lip 28 of the inner diameter lip 26a is pressed between the encoder 25b and the hub 3 by being pressed by the pressing surface 32 of the pressing jig 30a, and is sandwiched in an inverted state. Then, a sealing device is formed by contacting the outer peripheral surface of the hub 3 over the entire periphery with the leading edge of the inner side lip 28 having a tightening margin. In addition, the force that the internal lip 28 tries to recover to the inverted state becomes a force in the compression direction and is added to the tightening force, thereby obtaining the same effect as when the tightening force is substantially increased and improving the sealing performance. ing.
Further, since the outer lip 27 comes into contact with the hub 3 by an outward lip shape which is highly effective in preventing water from entering from the outside, the sealing performance at the fitting surface between the hub 3 and the slinger 16 is further improved. I can do things.

In the case of the present embodiment, since both the outer lip 27 and the inner lip 28 are in contact with the hub 3, the fitting portion between the rotating cylindrical portion 18 that is a fitting surface between metals and the hub 3 is excellent. Can be sealed. Further, in the press-fitting process of the combined seal ring 12b, the inner lip 26a is pushed by the same surface as the pressing part 32, so that the press-fitting jig 30a can be easily manufactured and managed.
In addition, when the inner diameter lip 26a of the present embodiment is vulcanized and molded, a slight undercut (unreasonable) occurs, so that it is preferable to apply to a magnetic rubber with a small content of magnetic material. Further, it is preferable to apply to a magnetic rubber whose base material is a rubber material which has high strength immediately after vulcanization molding and does not require secondary vulcanization, such as nitrile rubber (NBR).

  The wheel support bearing unit with an encoder according to the present invention is provided with a sealing device with an encoder in an opening of a bearing internal space formed between the stationary side race ring (outer ring) and the rotation side race ring (hub). The present invention can be applied to a bearing unit for supporting wheels.

DESCRIPTION OF SYMBOLS 1 Bearing support unit with an encoder 2 Outer ring 3 Hub 4 Outer ring raceway 5 Inner ring raceway 6 Ball 7 Cage 8 Static side flange 9 Rotation side flange 10 Bearing inner space 11 Seal ring 12, 12a, 12b Combination seal ring 13 Core 14 Sealing material 15a, 15b, 15c Sealing lip 16 Slinger 17 Sealing ring 18 Rotating side cylindrical part 19 Rotating side annular part 20 Core metal 21 Sealing material 22a, 22b, 22c Sealing lip 23 Stationary side cylindrical part 24 Stationary side annular part 25 , 25a, 25b Encoder 26, 26a Inner lip 27 External lip 28 Internal lip 29 Gasket 30, 30a Press fitting jig 31 Outer ring contact part 32 Press part 33 Projection part

Claims (2)

A rotating side raceway having a rotating side track by forming a rotating side flange for wheel attachment, a stationary side raceway having a stationary side raceway, and freely rotatable between the rotating side raceway and the stationary side raceway A seal ring and a slinger, each of which includes a plurality of rolling elements provided and closes an end opening of a bearing internal space existing between the circumferential surfaces facing each other of the rotation side raceway and the stationary side raceway. The slinger has a L-shaped metal plate and an annular shape as a whole, and is fitted to and fixed to the peripheral surface of the rotating raceway, and the rotating A rotating-side circular ring portion that is bent toward the circumferential surface of the stationary-side raceway ring from the inner end green in the axial direction of the side cylindrical portion, and S poles and N poles are alternately magnetized along the circumferential direction. An encoder, which is a permanent magnet, is disposed in the axial direction of the rotating side annular portion. In the wheel supporting bearing unit with an encoder which is supported fixed to the surface,
With an encoder, wherein a lip extending from the rotary side raceway side of the encoder is in contact with a peripheral surface of the rotary side raceway with a margin in an axially inverted state Wheel support bearing unit.   In a free state, the lip protrudes inward in the axial direction from the encoder, and is pressed and reversed by a press-fitting jig that press-fits the slinger into the rotating raceway, and comes into contact with the circumferential surface of the rotating raceway. The wheel support bearing unit with an encoder according to claim 1.

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