JP2014084893A - Bearing unit with rotation speed detection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a structure that prevents abrasion of an encoder and does not increase the width dimension of a bearing unit, at low cost.SOLUTION: An auxiliary seal 41 having an axial lip 43 and a radial lip 44 is fitted and fixed to the inner diameter part of a sensor holder 26a. The axial lip 43 is slidably contacted or proximately opposite to the end surface of an inner ring 2b, and the radial lip 44 is slidably contacted or proximately opposite to the outer peripheral surface of an outer ring 13 for a constant velocity joint. The width dimension of a guide part 45 provided at the tip of the radial lip 44 is larger than the chamfer width dimension of the outer ring for a constant velocity joint.

Description

  The present invention relates to a bearing unit with a rotational speed detecting device that rotatably supports a wheel with respect to a suspension device and measures the rotational speed of the wheel.

  2. Description of the Related Art Conventionally, automobile wheels are rotatably supported by a double-row angular type rolling bearing unit or the like with respect to a suspension device. Moreover, in order to ensure the running stability of the vehicle, a vehicle running stabilization device such as an anti-lock brake system (ABS) or a traction control system (TCS) is used, and these running stabilization devices are controlled. For this purpose, information on the rotational speed of the wheel is required. FIG. 5 shows an example of a conventional structure of such a bearing unit with a rotational speed detection device for driving wheels (front wheels of FF vehicles, rear wheels of FR vehicles and RR vehicles, all wheels of 4WD vehicles). ing. This bearing unit with a rotational speed detector includes an outer ring 1, a first inner ring 2a and a second inner ring 2b, a plurality of tapered rollers 3, 3 each of which is a rolling element, and a hub 4 which is a shaft member. It has.

  Of these, the outer ring 1 has a first outer ring raceway 5a and a second outer ring raceway 5b each having a conical surface on the inner peripheral surface, and a coupling flange 6 on the outer peripheral surface. The inclination directions of the first and second outer ring raceways 5a and 5b are opposite to each other. The first inner ring 2a forms a conical first inner ring raceway 7a on the outer peripheral surface, and the second inner ring 2b forms a conical second inner ring raceway 7b on the outer peripheral surface. doing. Each of the first and second inner rings 2a and 2b is arranged concentrically with the outer ring 1 on the radially inner side of the outer ring 1 in a state where the respective end surfaces on the small diameter side are abutted with each other. The tapered rollers 3, 3 are provided between the first outer ring raceway 5a and the first inner ring raceway 7a, and between the second outer ring raceway 5b and the second inner ring raceway 7b. Each is provided so that it can roll freely. A preload is applied to each of these tapered rollers 3 and 3 by a contact angle of a rear combination type.

  The hub 4 has a mounting flange 9 for supporting and fixing a wheel at a portion near the outer end in the axial direction of the outer peripheral surface, a cylindrical surface portion 10 at the center or inner end, and a spline hole 11 at the center. , Each formed. Then, the first and second inner rings 2a and 2b are externally supported by the cylindrical surface portion 10 in such a state that a tightening margin is provided (press-fit state). In this state, the large-diameter side end surface of the first inner ring 2a is abutted against the step surface 12 provided at the base end portion of the cylindrical surface portion 10, and the large-diameter side end surface of the second inner ring 2b is The hub 4 protrudes inward in the axial direction from the inner end surface of the hub 4. Note that “outside in the axial direction” means the outside in the width direction of the vehicle in the assembled state in the automobile, 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, is referred to as the inside in the axial direction.

  A combination seal ring 8a is attached between the outer peripheral surface of the outer ring 1 in the axial direction and the outer peripheral surface of the first inner ring 2a on the large diameter side, and the inner periphery of the outer ring 1 in the axial direction. By inserting a combination seal ring 8b between the surface and the outer peripheral surface on the large-diameter side of the second inner ring 2b, the foreign material enters and is enclosed in the internal space where the tapered roller 3 is installed. Prevents leakage of grease.

  The combination seal ring 8 b includes a seal ring 22, a slinger 21, and an encoder 20 each having an annular shape. Of these, the seal ring 22 includes a cored bar 23 and a plurality of seal lips 24. The metal core 23 is formed by bending a metal plate such as a mild steel plate to have an L-shaped cross section and an annular shape as a whole, and is fitted and fixed to the inner end in the axial direction of the outer ring 1. Each of the seal lips 24 is made of an elastic material such as an elastomer such as rubber, and is provided over the entire circumference of the core metal 23 with the respective base end portions attached and fixed to the core metal 23. Yes. The slinger 21 has an L-shaped cross section and is formed into an annular shape as a whole, and is externally fitted and fixed to the outer peripheral surface on the large diameter side of the second inner ring 2b. The tip edge of each seal lip 24 is in sliding contact with the outer circumferential surface or the outer circumferential surface of the slinger 21 over the entire circumference.

  The encoder 20 has an annular shape, and is attached to the inner side surface (the right side surface in FIG. 5) of the slinger 21 concentrically with the hub 4 by bonding, baking, or the like. The encoder 20 is made of a rubber magnet or a plastic magnet, 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 in the axial direction, which is the detected surface of the encoder 20. Then, the sensor 25 is fixed inside the sensor holder 26 that is externally fitted and fixed to the axially inner end opening of the outer ring 1, and the detection portion of the sensor 25 is opposed to the detection surface of the encoder 20. Thus, the rotational speed of the wheel coupled and fixed to the hub 4 is detected.

The sensor holder 26 is made of a metal plate such as a mild steel plate and has a substantially L-shaped cross section and is formed in an annular shape as a whole. In such a sensor holder 26, the outer end portion in the axial direction of the cylindrical portion is fitted and fixed to the inner end portion in the axial direction of the outer ring 1 by an interference fit. The sensor 25 is coupled and fixed inside the sensor holder 26 by screwing or bonding.
The signal representing the rotational speed of the wheel obtained from the sensor 25 facing the detection surface of the encoder 20 is an anti-lock brake system (ABS), a traction control system (TCS), etc. Furthermore, it is input to a controller (not shown) of the vehicle stabilization device for ensuring the stability of the vehicle during turning.

  When the bearing unit with a rotational speed detection device as described above is assembled in an automobile, a spline shaft 14 that is a drive shaft fixed at the center of the outer end surface of the outer ring 13 for a constant velocity joint is inserted into the spline hole 11. In addition, the outer diameter side portion of the outer end surface of the constant velocity joint outer ring 13 is abutted against the large diameter side end surface of the second inner ring 2b. In this state, the nut 16 is screwed into a male screw portion provided at a portion protruding from the spline hole 11 at the tip end portion of the spline shaft 14 and further tightened. As a result, the spline shaft 14 and the hub 4 are coupled and fixed to each other, and the stepped surface 12 provided on the outer peripheral surface of the hub 4 and the outer ring 13 for the constant velocity joint are removed from each other based on the tightening force of the nut 16. A force in a direction approaching each other is applied to each of the first and second inner rings 2a and 2b sandwiched between the end faces. The coupling flange 6 is coupled and fixed to a knuckle 17 constituting a suspension device using bolts 18, and wheels and brake rotors (not shown) are supported and fixed to the mounting flange 9.

  In the case of the combination seal ring 8b shown in FIG. 5, the encoder 20 is exposed to the external space (the surrounding environment in which foreign matter such as muddy water and dust may be present). For this reason, it cannot be denied that a foreign object adheres to the detection surface of the encoder 20 and the encoder 20 is worn. When the encoder 20 is worn, the amount of magnetic flux (magnetic flux density) that enters and exits the detection surface of the encoder 20 and passes through the detection unit of the sensor 25 is reduced. There is a possibility that accuracy or reliability may be lowered. For this reason, conventionally, a part of the outer ring 13 for constant velocity joint and a part of the sensor holder 26 are brought close to each other and a labyrinth seal is formed on the part, so that the surface to be detected of the encoder 20 is made. To prevent the adhesion of foreign matter. However, the effect of preventing foreign matter adhesion by the labyrinth seal is not always sufficient, and the encoder 20 may be worn with use over a long period of time.

  On the other hand, Patent Document 1 describes a structure that prevents foreign matter from adhering to the encoder. A sensor seal is mounted between the magnetic encoder and the external space to prevent foreign substances existing in the external space from adhering to the encoder. In addition, a drain is provided at the bottom of the cover to prevent foreign matter such as muddy water and pebbles from staying in the cover.

JP 2010-043711 A

  However, in this prior art, a small-diameter portion for mounting the sensor seal is formed on the inner side in the axial direction of the inner ring. Therefore, the small-diameter portion increases the width direction dimension of the inner ring, and consequently the width of the entire bearing unit. The dimensions will increase. Therefore, it may be difficult to apply this structure to the front wheels (steering wheels and drive wheels) of FF vehicles that require the virtual kingpin angle to coincide with the center of the constant velocity joint. . Further, when the structure of Patent Document 1 is applied to a so-called first and second generation wheel support bearing unit, such as the bearing unit with a rotation speed detection device shown in FIG. Since the shapes of the inner rings are different, there are problems that two types of inner rings are required and the cost is increased, and the assembling work of each inner ring becomes complicated.

  In view of the circumstances as described above, the present invention has been invented to realize a structure capable of preventing wear of the encoder and not increasing the width of the bearing unit at a low cost.

A bearing unit with a rotational speed detection device according to the present invention includes an outer ring having an outer ring raceway on an inner peripheral surface, an inner ring having an inner ring raceway on an outer peripheral surface, and a plurality of portions provided between the outer ring raceway and the inner ring raceway. A rolling member, a cylindrical member fixed in contact with the end face of the inner ring, an encoder supported and fixed to the end of the inner ring, an annular sensor holder fixed to the end of the outer ring, and the sensor A sensor supported by a holder and facing the encoder is provided.
In particular, in the bearing unit with a rotational speed detection device of the present invention, an auxiliary seal having at least one seal lip is fitted and fixed to the inner diameter portion of the sensor holder, and the seal lip is slidably contacted or closely opposed to the end face of the inner ring. At the same time, a guide portion is formed at the tip end portion of the seal lip that is in sliding contact with or close to the outer peripheral surface of the cylindrical member, and whose inner peripheral surface is a cylindrical surface or a partial conical surface.

Furthermore, the axial width dimension of the guide portion is larger than the axial width dimension of the chamfer formed on the portion of the cylindrical member that contacts the end face of the inner ring.
The cylindrical member is an outer ring of a constant velocity joint.
The cylindrical member is a nut.

According to the bearing unit with a rotational speed detection device of the present invention configured as described above, it is possible to realize a structure that can prevent wear of the encoder and that does not increase the width of the bearing unit at low cost.
To prevent wear of the encoder, the auxiliary seal is fitted and fixed to the inner surface of the sensor holder, and the encoder is provided in a seal space that is cut off from the external space. This can be achieved by preventing the adhesion of.
Further, the width dimension of the bearing unit is not increased by making the seal lip of the auxiliary seal slidably contact or closely face the outer peripheral surface of the cylindrical member (constant velocity joint or nut). With this configuration, since the seal space is formed by closing the space between the auxiliary seal and the outer peripheral surface of the cylindrical member and the end surface of the inner ring, it is not necessary to increase the width of the inner ring, and the width of the bearing unit is Does not increase.
Further, the cost reduction can be achieved by making it possible to use two inner rings having the same shape as in the conventional structure shown in FIG. 5 without newly forming a small-diameter portion or the like on the inner ring. Further, by providing a guide portion at the tip of the seal lip, the assembly work of the cylindrical member to the bearing unit is facilitated.

The fragmentary sectional view which shows the 1st example of embodiment of this invention. The fragmentary sectional view which shows the 2nd example of embodiment of this invention. The fragmentary sectional view which shows the 3rd example of embodiment of this invention. Sectional drawing which shows the 4th example of embodiment of this invention. Sectional drawing which shows an example of the conventional structure.

[First example of embodiment]
FIG. 1 shows a first example of an embodiment of the present invention. The feature of this embodiment is the structure of the sensor holder 26a constituting the rotational speed detection device and the auxiliary seal 40 fitted and fixed to the inner diameter portion thereof. Since the structure and operation of the other parts are almost the same as those of the conventional structure shown in FIG. 5 described above, the same parts are denoted by the same reference numerals, and redundant description is omitted or simplified. The characteristic part of the embodiment and the part different from the conventional structure will be mainly described.

  Also in this example, an internal space in which the combination seal ring 8b is provided between the large-diameter outer peripheral surface of the second inner ring 2b and the inner peripheral surface of the outer ring 1 in the axial direction, and the tapered roller 3 is installed. The inner end opening is closed. This combination seal ring 8 b includes a slinger 21 fitted and fixed to the second inner ring 2 b and a seal ring 22 fitted and fixed to the outer ring 1. The seal ring 22 includes a cored bar 23 having an L-shaped cross section and formed in an annular shape, and a sealing material 24 reinforced by the cored bar 23. The leading edge of the sealing material 24 is brought into sliding contact with the slinger 21. The encoder 20 is attached to the inner side surface (the right side surface in FIG. 1) of the slinger 21 by bonding or baking. The encoder 20, which is a permanent magnet, is magnetized in the axial direction, and the magnetization direction is changed alternately at equal intervals over the circumferential direction. Therefore, the south pole and the north pole are alternately arranged at equal intervals on the inner side surface in the axial direction, which is the detected surface of the encoder 20.

  On the other hand, a sensor holder 26a is fitted and fixed to the inner end of the outer ring 1 in the axial direction. The sensor holder 26a is formed into a ring shape by drawing a nonmagnetic metal plate such as an austenitic stainless steel plate, and has an inner edge in the axial direction and an inner diameter side cylinder of the outer diameter side cylindrical portion 28. The inner end edge in the axial direction of the portion 30 is configured to be continuous by an annular portion 29. Of these, the outer diameter side cylindrical portion 28 has sufficient rigidity by forming the cross section into a crank shape, and the outer half of the axial direction is fitted and fixed to the inner end of the outer ring 1 in the axial direction. Positioning in the axial direction is performed by abutting the intermediate portion in the axial direction against the inner end surface of the outer ring 1 in the axial direction.

A sensor 25a in which the detection unit 27 is embedded is supported and fixed on the inner half in the axial direction of the sensor holder 26a. The sensor 25 a has a rectangular parallelepiped shape that is long in the attached direction, is inserted from the outer diameter side of the sensor insertion hole 31 formed in the outer diameter side cylindrical portion 28, and is the outer periphery of the inner diameter side cylindrical surface 30. In a state of being abutted against the surface, it is fixed by adhesion or the like. In this state, the detection unit 27 of the sensor 25a is opposed to the inner side surface in the axial direction, which is the detection surface of the encoder 20, with a small gap.
When the encoder 20 rotates together with the hub 4 and the second inner ring 2b, the magnetic flux density in the detection unit 27 changes. Based on the change in the magnetic flux density, the sensor 25a outputs a signal that changes at a frequency proportional to the rotational speed of the wheel fixed to the hub 4.

  Further, the auxiliary seal 40 is fitted and fixed to the inner peripheral surface of the inner diameter side cylindrical portion 30. The auxiliary seal 40 includes a cored bar 41 and a sealing material 42 having a plurality of lips. The lip is disposed on the outer peripheral surface of the outer ring 13 for the constant velocity joint and the inner end surface in the axial direction of the second inner ring 2b. The seal space 50 in which the encoder 20 is installed is shut off from the external space by sliding contact or close proximity. The core metal 41 is a non-magnetic metal plate that is L-shaped in cross section and is press-formed as a whole in an annular shape, and is fitted and fixed to the inner peripheral surface of the inner diameter side cylindrical portion 30. The sealing material 42 is formed in an annular shape by an elastic material such as rubber or elastomer, and has a base end portion coupled and supported on the inner peripheral surface of the cored bar 41, and includes an axial lip 43 and a radial lip 44. Yes. The axial lip 43 extends radially outward from the axially outer side portion of the sealing material 42 toward the axially outer side, and the tip portion thereof is the axially inner end surface of the second inner ring 2b. They are in sliding contact or close to each other. The radial lip 44 extends radially inward from the portion closer to the inner diameter of the sealing material 42 toward the inner side in the axial direction, then extends radially outward toward the inner side in the axial direction, and further extends inward in the axial direction. A guide 45 is formed. The portion of the radial lip 44 located closest to the inner diameter side is slidably contacted or closely opposed to the outer peripheral surface of the constant velocity joint outer ring 13.

  The guide portion 45 is a tip portion of the radial lip 44, and its inner peripheral surface is formed into a cylindrical surface shape, and its axial width dimension b is set to be outside of the constant velocity joint outer ring 13 in the axial direction. The end face is larger than the axial width dimension a of the chamfer formed at the portion in contact with the inner end face in the axial direction of the second inner ring 2b (a <b). Therefore, when the bearing unit with a rotational speed detection device of this example is assembled to an automobile, the spline shaft 14 is inserted into the spline hole 11 (see FIG. 5), and the outer ring 13 for the constant velocity joint is moved in the axial direction. When the outer diameter side portion of the end face is abutted against the larger diameter end face of the second inner ring 2b, the inner diameter side end of the radial lip 44 is the outer diameter edge of the axial outer end face of the constant velocity joint outer ring 13. To prevent inversion due to interference. Further, if the inner peripheral surface of the guide portion 25 is formed in a partial conical surface shape having a diameter that increases inward in the axial direction, the reversal of the radial lip 44 can be prevented more reliably.

In the lower part of the sensor holder 26a, there is provided a drainage hole (not shown, see FIG. 4 described later) for discharging muddy water or the like that has entered from between the sensor insertion holes 31 and the like to the external space. This prevents muddy water and the like from accumulating in the seal space 50.
Further, on the inner peripheral surface of the auxiliary seal 40, the distance from the tip end portion of the axial lip 43 to the sliding contact portion of the radial lip 44 with the outer ring 13 for the constant velocity joint increases toward the outer side in the axial direction. It has a partial conical surface shape that becomes the diameter. Therefore, the muddy water that has entered the space surrounded by the auxiliary seal 40, the second inner ring 2b, and the constant velocity joint outer ring 13 is guided by gravity and collected in the lower part without staying, and then the axial lip 43 is formed. Due to the shape of the self-leakage and the swing-off effect due to the rotation of the outer ring 13 for the constant velocity joint, it is further guided to the lower part of the sensor holder 26a and discharged from the drain hole to the external space.

In the case of the bearing unit with a rotational speed detecting device as described above, it is possible to realize a structure that can prevent wear of the encoder and that does not increase the width of the bearing unit at a low cost.
In order to prevent the wear of the encoder, the auxiliary seal 41 having the axial lip 43 and the radial lip 44 is fitted and fixed to the inner diameter portion of the sensor holder 26a, and the encoder 20 is sealed from the external space. This is achieved by providing it inside. This configuration prevents foreign matter from adhering to the detection surface of the encoder 20 and can always keep the detection surface of the encoder 20 in a clean state, so that the performance of the rotation detection device is stable over a long period of time. Can be maintained. Since the combination seal ring 8b is further mounted on the bearing inner side of the seal space 50, foreign matter can be prevented from entering the inner space of the bearing in which the tapered rollers 3 are installed, and the grease sealed in the inner space. Is prevented from adhering to the encoder 20.

Further, the width dimension of the bearing unit is not increased by making the radial seal lip 44 of the auxiliary seal 40 slidably contact or closely face the outer peripheral surface of the constant velocity joint outer ring 13 which is a cylindrical member. In this configuration, the seal space 50 is formed by closing the space between the auxiliary seal 40 and the outer peripheral surface of the constant velocity joint outer ring 13 and the end surface of the second inner ring 2b. Therefore, it is not necessary to increase the width dimension of the second inner ring 2b, and the width dimension of the bearing unit does not increase.
Further, in order to reduce the cost, it is not necessary to newly provide a small-diameter portion or the like in the inner ring in order to form the seal space 50, and the first inner ring 2a and the second inner ring 2 having the same shape as in the conventional structure shown in FIG. This is achieved by enabling the use of the inner ring 2b. Further, since the guide portion 45 is provided at the tip of the radial sea lip 44, the radial lip 44 is prevented from being reversed by the axial outer end surface of the outer ring 13 for the constant velocity joint when the bearing unit is assembled to the automobile. Assembly work is easy.

[Second example of embodiment]
FIG. 2 shows a second example of the embodiment of the present invention. In the case of this example, a part of the radial lip 44a is extended outward in the axial direction so as to be close to and opposed to the axial inner end surface of the second inner ring 2b, thereby replacing the axial lip 43 in the first example. The radial width of the radial lip 44a is small and reduced in size so that the radial lip 44a does not protrude inward in the axial direction (is located on the outer side in the axial direction) from the axial inner end surface of the core metal 41 of the auxiliary seal 40a. . And the inner peripheral surface of the guide part 45a which is the front-end | tip part of the radial lip 44a is made into the shape of a partial conical surface which becomes large diameter toward the inner side in the axial direction, and the axial width dimension b of the guide part 45a is the same as the above. The chamfer width dimension a of the outer end surface in the axial direction of the outer ring 13 for the speed joint is set to be larger (a <b). Further, the sealing member 42a constituting the auxiliary seal 40a has a collar lip 46, and this collar lip 46 extends inward in the axial direction, and its tip is formed on the outer ring 13 for the constant velocity joint. The stepped portion 47 is slidably contacted or closely opposed to the axially outer end surface.

  In the case of this example having the above-described configuration, by providing the collar lip 46 on the outer space side of the radial lip 44a, mud water or the like wound up by the wheels can be prevented from hitting the radial lip 44a directly. Therefore, the sealing performance (mud water resistance) can be improved. Further, since the inner peripheral surface of the guide portion 45a has a partially conical surface shape that increases in diameter toward the inner side in the axial direction, when the bearing unit is assembled to the constant velocity joint, the radial lip 44a is connected to the outer ring 13 for the constant velocity joint. It does not invert due to interference. Other configurations and operations are the same as those of the first example of the embodiment of the present invention described above.

[Third example of embodiment]
FIG. 3 shows a third example of the embodiment of the present invention. In the case of this example, it extends outward in the axial direction on the outer diameter side (bearing inner side) of the axial lip 43 in the first example described above, and is slidably contacted or closely opposed to the axial inner end of the second inner ring 2b. An axial lip 43a is further provided. The radial width of the radial lip 44b is small and reduced in size so that the radial lip 44b does not protrude inward in the axial direction (positioned outward in the axial direction) from the axial inner end surface of the core metal 41 of the auxiliary seal 40b. . And the inner peripheral surface of the guide part 45b which is the front-end | tip part of the radial lip 44b is made into the partial conical surface shape which becomes large diameter as it goes to an axial direction inner side, and the axial direction width dimension b of the guide part 45b is the said etc. The chamfer width dimension a of the outer end surface in the axial direction of the outer ring 13 for the speed joint is set to be larger (a <b).
Since the sealing material 42b of the auxiliary seal 40b is downsized (space-saving) so as not to protrude inward in the axial direction from the core metal 41 and the sensor holder 26a, the sensor holder 26a (auxiliary seal 40b) and a constant velocity joint are used. Interference with the outer ring 13 is prevented. Further, an axial lip 43a is added, and the core metal 41 prevents direct hitting of the radial lip 44b such as muddy water, thereby improving the sealing performance. Other configurations and operations are the same as those of the first example of the embodiment of the present invention described above.

[Fourth example of embodiment]
FIG. 4 shows a fourth example of the embodiment of the present invention, in which the invention is applied as a bearing unit with a rotational speed detection device for driven wheels (rear wheels of FF vehicles, front wheels of FR vehicles and RR vehicles). It is an example. In the case of this example, since the bearing unit is for a driven wheel, no spline hole is provided at the center of the hub 4b, and instead, a male screw 51 is provided at the inner end in the axial direction of the hub 4b. A large-diameter side end surface of the second inner ring 2b is pressed against the stepped surface 12 formed on the outer peripheral surface of the hub 4b by a nut 52 that is screwed into the male screw 51 and tightened. And by restraining in this way, a force in a direction approaching each other in the axial direction is applied to each of the first and second inner rings 2a, 2b. The nut 52 has an outer peripheral surface finished in a cylindrical shape, and through holes 54 for engaging a fastening tool are provided at a plurality of positions on the side surface at predetermined intervals in the circumferential direction. The radial lip 44 of the auxiliary lip 40 is slidably contacted or closely opposed to the outer peripheral surface of the nut 52, which is a cylindrical member. Also in this example, the inner peripheral surface of the guide portion 45 that is the tip portion of the radial lip 44 is a cylindrical surface (or a partial conical surface shape having a larger diameter toward the inner side in the axial direction), and the guide portion 45. The axial width dimension of the nut 52 is made larger than the axial width dimension of the chamfer formed on the axially outer end face of the nut 52 at the portion in contact with the axially inner end face of the second inner ring 2b. Other configurations and operations are the same as those of the first example of the embodiment of the present invention described above.

In addition, this invention is not limited to each embodiment mentioned above, A various deformation | transformation is possible. For example, in the bearing unit, a caulking portion is formed at the inner end portion in the axial direction of the hub, and the large-diameter side end surface of the second inner ring is suppressed by the caulking portion (so-called third generation wheel support bearing unit). In this case, a radial lip of the auxiliary seal is slidably contacted or closely opposed to the caulking portion. Further, balls can be used instead of tapered rollers as rolling elements for the purpose of reducing the weight and torque of the vehicle.

  The bearing unit with a rotational speed detection device of the present invention can be applied to a wheel support bearing unit that rotatably supports a wheel of an automobile.

DESCRIPTION OF SYMBOLS 1 Outer ring 2a, 2b Inner ring 3 Tapered roller 4, 4b Hub 5a, 5b Outer ring raceway 6 Coupling flange 7a, 7b Inner ring raceway 8a, 8b Combination seal ring 9 Mounting flange 10 Cylindrical surface part 11 Spline hole 12 Step surface 13 Outer ring for constant velocity joint 14 spline shaft 15 male thread portion 16 nut 17 knuckle 18 bolt 20 encoder 21 slinger 22 seal ring 23 cored bar 24 seal lip 25, 25a sensor 26, 26a sensor holder 27 detection portion 28 outer diameter side cylindrical portion 29 annular portion 30 inner diameter side Cylindrical portion 31 Sensor insertion hole 40, 40a, 40b Auxiliary seal 41 Core metal 42, 42a, 42b Sealing material 43, 43a Axial lip 44, 44a, 44b Radial lip 45, 45a, 45b Guide portion 46 庇 Lip 47 Step portion 50 Le space 51 external thread 52 nut 53 drain hole 54 through hole

Claims (4)

An outer ring having an outer ring raceway on the inner peripheral surface, an inner ring having an inner ring raceway on the outer peripheral surface, a plurality of rolling elements provided between the outer ring raceway and the inner ring raceway, and abutting against the end face of the inner ring A cylindrical member, an encoder supported and fixed to the end of the inner ring, an annular sensor holder fixed to the end of the outer ring, and a sensor supported by the sensor holder and facing the encoder. In the provided bearing unit with a rotational speed detection device,
An auxiliary seal having at least one seal lip is fitted and fixed to the inner diameter portion of the sensor holder, and the seal lip is slidably contacted or closely opposed to the end surface of the inner ring and is slidably contacted or adjacent to the outer peripheral surface of the cylindrical member. A bearing unit with a rotational speed detecting device, characterized in that a guide portion that is opposed and has an inner peripheral surface that is a cylindrical surface or a partial conical surface is formed at a tip portion of the seal lip.   2. The rotational speed detecting device according to claim 1, wherein an axial width dimension of the guide portion is larger than an axial width dimension of a chamfer formed on a portion of the cylindrical member that contacts the end face of the inner ring. Bearing unit.   3. The bearing unit with a rotational speed detection device according to claim 1, wherein the cylindrical member is an outer ring of a constant velocity joint.   The bearing unit with a rotation speed detecting device according to claim 1 or 2, wherein the cylindrical member is a nut.

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