CN203702886U - Bearing unit with rotational speed detection device - Google Patents

Abstract

The utility model relates to a bearing unit with a rotational speed detection device, which supports a wheel freely rotatable with respect to a suspension device, and measures the rotational speed of the wheel. On the inner diameter of the sensor holder, an auxiliary seal with an axial flange and a radial flange is fitted and fixed, so that the axial flange is in sliding contact with or close to the end face of the inner ring, and the radial flange The edge is in sliding contact with or close to and opposed to the outer peripheral surface of the constant velocity coupling outer ring. The width dimension of the guide portion provided at the front end of the radial flange is larger than the chamfer width dimension of the outer ring for constant velocity coupling. Thus, a bearing unit that prevents wear of the encoder without increasing the width dimension can be provided at low cost.

Description

Bearing unit with speed detection device

technical field

The utility model relates to a bearing unit for freely rotatably supporting automobile wheels.

Background technique

Conventionally, a wheel of an automobile is rotatably supported by a rolling bearing unit, and the rotational speed thereof is detected. A bearing unit with a rotational speed detection device of a conventional structure shown in FIG. 3 has an outer ring 1 , inner rings 2 a , 2 b , tapered rollers 3 as rolling elements, and a hub 4 .

Outer ring 1 forms outer ring raceways 5a, 5b on the inner peripheral surface, and forms coupling flange 6 on the outer peripheral surface. The inner rings 2a, 2b form inner ring raceways 7a, 7b on the outer peripheral surfaces, respectively. A plurality of tapered rollers 3 are provided so as to be rotatable between the outer ring raceways 5a, 5b and the inner ring raceways 7a, 7b. The hub 4 is formed with a mounting flange 9 for supporting and fixing the wheel on the outer peripheral surface near the axially outer end, and a cylindrical surface 10 is formed on the inner end surface from the central part, and a spline is formed on the central part. Hole 11. The respective inner rings 2a, 2b are press-fitted and fitted to the cylindrical surface portion 10 . In addition, regarding the axial direction, outer means the outer side in the width direction of the vehicle in the assembled state to the automobile, and is the left side in each figure. On the other hand, regarding the axial direction, the right side in each figure on the center side in the width direction of the vehicle is referred to as the inside.

Openings at both axial ends of the outer ring 1 are closed by combination seal rings 8a, 8b, respectively. The ring-shaped encoder 20 is a permanent magnet such as a rubber magnet, and is vulcanized and bonded to the axial inner surface of the combination seal ring 8b. S poles and N poles are arranged alternately and at equal intervals along the circumferential direction on the axial inner surface of the encoder 20 as the surface to be detected. A sensor 25 is fixed inside a sensor holder 26 which is externally fitted and fixed to an opening at an axially inner end of the outer ring 1 . By making the detecting part of the sensor 25 face the detected surface of the encoder 20 , the rotational speed of the wheel coupled and fixed to the hub 4 is detected.

In the case of assembling the above-mentioned bearing unit with a rotational speed detection device to an automobile, the spline shaft 14 fixedly provided at the center of the outer end surface of the outer ring 13 for a constant velocity coupling is inserted into the spline hole 11, and , the outer diameter side portion of the outer end surface of the constant velocity coupling outer ring 13 is brought into contact with the large diameter side end surface of the inner ring 2b. In this state, the nut 16 is fastened to the front end portion of the spline shaft 14 , whereby the spline shaft 14 and the hub 4 are coupled and fixed.

However, since the encoder 20 is exposed in the external space, it cannot be denied that foreign matter may adhere to the detected surface of the encoder 20 and cause abrasion. Patent Document 1 discloses a structure in which a sensor seal is installed between the encoder and the external space to prevent foreign matter from adhering to the encoder. However, the installation of the sensor seal increases the width direction dimension of the inner ring, and further The overall width dimension of the bearing unit has been increased.

Patent Document 1: Japanese Patent Application Publication No. 2010-043711

Utility model content

In order to solve the above problems, the utility model (1) provides a bearing unit with a speed detection device, which has: an outer ring with an outer ring raceway on the inner peripheral surface; an inner ring raceway on the inner peripheral surface; Inner ring; a plurality of rolling elements arranged between the raceway of the outer ring and the raceway of the inner ring; a cylindrical part fixed by abutting against the end face of the inner ring; an encoder supported and fixed on the end of the inner ring; An annular sensor holder fixed on the end of the sensor holder; and a sensor supported on the sensor holder and opposite to the encoder, the bearing unit with a rotation speed detection device is characterized in that, on the inner diameter of the sensor holder, An auxiliary seal having at least one sealing lip is fitted and fixed, and the sealing lip is in sliding contact with or close to and opposite to the end surface of the inner ring, and is in sliding contact with or close to and opposite to the outer peripheral surface of the cylindrical member, and at the front end of the sealing lip A guide portion whose inner peripheral surface is a cylindrical surface or a partial conical surface is formed on the top.

(2) The above-mentioned bearing unit with a rotation speed detection device is characterized in that a chamfer is formed on a portion of the cylindrical member that abuts against the end surface of the inner ring, and the axial width dimension of the guide portion is larger than the axial width of the chamfer. The size is large.

(3) The above bearing unit with a rotational speed detection device is characterized in that the cylindrical member is an outer ring of a constant velocity coupling.

(4) In the above-mentioned bearing unit with a rotational speed detection device, the cylindrical member is a nut.

According to the bearing unit with rotational speed detection device of the present invention, the auxiliary seal is fitted and fixed on the inner diameter surface of the sensor holder, and the encoder is arranged in the sealed space, thereby preventing the detected surface of the encoder from being damaged. wear and tear. In addition, since the sealing lip is brought into sliding contact with or close to and opposed to the outer peripheral surface of the cylindrical member to form a sealed space, it is not necessary to increase the width of the inner ring and the width of the bearing unit does not increase. Furthermore, the guide portion is provided at the front end of the seal lip, thereby facilitating the assembly work of the cylindrical member to the bearing unit.

Description of drawings

FIG. 1 is a partial cross-sectional view of the periphery of a sensor holder according to the present embodiment.

Fig. 2 is a partial cross-sectional view around a sensor of a modified example.

Fig. 3 is a cross-sectional view of a bearing unit with a rotational speed detection device as an example of a conventional structure.

Detailed ways

The present embodiment is characterized by a structure in which the sensor holder 26a constituting the rotational speed detection device and the auxiliary seal 40 are fitted and fixed to the inner diameter portion thereof. The structures and functions of other parts are substantially the same as those of the conventional structure shown in FIG. Describe the center.

As shown in FIG. 1 , the axially inner end opening of the outer ring 1 is closed by a combination seal ring 8 b. The combination seal ring 8 b has a seal ring 22 fitted and fixed at the axially inner end of the outer ring 1 , and a slinger 21 fitted and fixed on the large-diameter side outer peripheral surface of the inner ring 2 b. A seal lip having a base end portion on the seal ring 22 is brought into sliding contact with the flinger 21 . An encoder 20 is vulcanized and bonded to the axial inner surface (the right side in FIG. 1 ) of the oil slinger 21 .

On the axial inner end portion of the outer ring 1 , a sensor holder 26 a which is integrally formed in an annular shape by a non-magnetic metal plate is fitted and fixed on the outside. In the sensor holder 26 a , the axially inner end edge of the radially outer cylindrical portion 28 and the axially inner end edge of the radially inner cylindrical portion 30 are continuous through the annular portion 29 . The outer diameter side cylindrical portion 28 has a crank shape in section, and its axially outer half is fitted and fixed on the axially inner end portion of the outer ring 1, and its axial middle portion is connected to the axial direction of the outer ring 1. The inner end faces abut. A drain hole (not shown) for draining moisture penetrating into the sensor holder 26 a to the outside is provided at a vertically lower portion of the sensor holder 26 a.

In addition, the sensor 25a covering and embedding the detecting portion 27 is supported and fixed on the axially inner half of the sensor holder 26a. The sensor 25 a is inserted from the outer diameter side of the sensor insertion hole 31 and is fixed by adhesion or the like in a state of being in contact with the outer peripheral surface of the inner diameter side cylindrical surface 30 . The detection portion 27 faces the axial inner surface of the encoder 20 with a slight gap therebetween.

An auxiliary seal 40 is fitted and fixed on the inner peripheral surface of the inner diameter side cylindrical portion 30 . The auxiliary seal 40 is composed of a metal core 41 and a sealing material 42 . The metal core 41 is a ring-shaped member made of a non-magnetic metal plate, and is fitted and fixed to the inner peripheral surface of the radially inner cylindrical portion 30 . The sealing member 42 is formed in an annular shape from an elastic material, has a base end portion bonded and supported on the inner peripheral surface of the metal core 41 , and has an axial flange 43 and a radial flange 44 . The axial flange 43 extends radially outward as it goes axially outward, and its front end portion is in sliding contact with or close to and opposed to the axially inner end surface of the inner ring 2b. The radial flange 44 extends radially inward as it goes axially inward, then extends radially outward as it goes axially inward, and further extends axially inward to form a guide portion 45 . Further, the radial flange 44 has a portion located on the innermost radial side in sliding contact with or close to and opposed to the outer peripheral surface of the constant velocity coupling outer ring 13 .

The guide portion 45 is a front end portion of the radial flange 44, and its inner peripheral surface is formed into a cylindrical surface shape. On the axially outer end surface of the constant velocity coupling outer ring 13, a chamfer is formed on the portion abutting against the axially inner end surface of the inner ring 2b, and the axial width dimension b of the guide portion 45 corresponds to the chamfer The axial width dimension a of the corner is relatively large (a<b). Therefore, when the bearing unit with a rotation speed detection device according to this embodiment is assembled to an automobile, the radially inner end of the radial flange 44 and the outer radial edge of the axially outer end surface of the constant velocity coupling outer ring 13 Interference prevents reverse rotation, making assembly easier.

As described above, by providing the encoder 20 inside the sealed space 50 separated from the external space, foreign matter is prevented from adhering to the detected surface of the encoder 20 and causing wear.

In addition, since the outer peripheral surface of the outer ring 13 for the constant velocity coupling 20 and the end surface of the inner ring 2 b are sealed by the auxiliary seal 40 to form the sealed space 50 , it is not necessary to increase the size as in Patent Document 1. The width dimension of the inner ring 2b will not increase the width dimension of the bearing unit.

In the modified example shown in FIG. 2 , a part of the radial flange 44 a extends axially outward to be close to and opposed to the axial inner end surface of the inner ring 2 b, thereby replacing the axial flange in FIG. 1 . 43. The radial flange 44 a does not protrude axially inward from the axially inner end surface of the metal core 41 . The inner peripheral surface of the guide portion 45a of the radial flange 44a is formed into a conical shape having a larger diameter as it goes axially inward. Furthermore, a shielding flange 46 is provided on the sealing member 42a constituting the auxiliary seal 40a to improve sealing performance. The shielding flange 46 extends inward in the axial direction, and its front end is in sliding contact with or close to and opposed to the bearing outer end surface of the stepped portion 47 formed on the constant velocity coupling outer ring 13 .

In addition, when the utility model is applied to a bearing unit with a rotating speed detection device for a driven wheel, a convex thread is provided on the axially inner end of the hub, and each nut is installed on the convex thread. The inner ring is fixed on the hub. The outer peripheral surface of the nut is processed into a cylindrical shape, and the radial flange of the auxiliary seal is brought into sliding contact with or close to and opposed to the outer peripheral surface of the nut as a cylindrical member. In addition, a chamfer is formed on the axially outer end surface of the nut at a portion abutting against the axially inner end surface of the inner ring, and the axial width dimension of the guide portion becomes smaller than the axial width dimension of the chamfer. big.

Claims (4)

1. the bearing unit with speed detector, it has: the outer ring on inner peripheral surface with outer ring raceway; On inner peripheral surface, there is the inner ring of inner ring raceway; Be located at the multiple rolling elements between described outer ring raceway and described inner ring raceway; The fixing cylinder part with the end face butt of described inner ring; At the fixing encoder of the end of described inner ring upper support; The circular sensor retainer of fixing on the end of described outer ring; Be bearing in described sensor retainer on and the sensor relative with described encoder, this bearing unit with speed detector is characterised in that,

On the inside diameter of described sensor retainer, the chimeric secondary seal with at least one sealing lip of having fixed, the end face sliding contact of described sealing lip and described inner ring or approach and relative, and, with the outer circumferential face sliding contact of described cylinder part or approach and relative, on the front end of described sealing lip, to be formed with inner peripheral surface be barrel surface or be the guide portion of part conical surface.

2. the bearing unit with speed detector according to claim 1, it is characterized in that, in part described cylinder part and end face butt described inner ring, be formed with chamfering, the axial width dimension of described guide portion is larger than the axial width dimension of described chamfering.

3. the bearing unit with speed detector according to claim 1 and 2, is characterized in that, described cylinder part is the outer ring of homokinetic joint.

4. the bearing unit with speed detector according to claim 1 and 2, is characterized in that, described cylinder part is nut.