WO2015041354A1

WO2015041354A1 - Wheel bearing device

Info

Publication number: WO2015041354A1
Application number: PCT/JP2014/074967
Authority: WO
Inventors: 佳祐森井; 慎太朗石川
Original assignee: Ntn株式会社; 佳祐森井; 慎太朗石川
Priority date: 2013-09-20
Filing date: 2014-09-19
Publication date: 2015-03-26
Also published as: JP6298262B2; JP2015058880A

Abstract

Provided is a wheel bearing device with which positioning accuracy and rotational-speed-detection accuracy and reliability are improved, while the rigidity of a protective cover is improved and deformation is inhibited. In this wheel bearing device, a magnetic encoder (13) is externally fitted to an inner race (5), and a bearing interior is sealed by attaching a seal (8) to an outer side of an opening between an external member (2) and an internal member (1), and attaching, to an inner side, a protective cover (14) which has been formed into a cap shape by being pressed worked from a non-magnetic steel sheet. The protective cover (14) is provided with: a cylindrical fitting part (14a) which is press fitted into an inner periphery of an end of the external member (2); a discoid shielding part (14c) which extends radially inward from the fitting part (14a); and a bottom part (14e) which continues on from the shielding part (14c) via a bent part (14d), and which covers an inner-side end of the internal member (1). Press working is used to integrally form a plurality of ribs (25) at a section joining the bottom part (14e) step to the shielding part (14c) and the bent part (14d). The plurality of ribs (25) are radially arranged at equal intervals in a circumferential direction.

Description

Wheel bearing device

The present invention relates to a wheel bearing device in which a wheel of an automobile or the like is rotatably supported and a protective cover for sealing the inside of the bearing is mounted.

There is provided a wheel bearing device in which a rotation speed detection device for detecting a rotation speed of a vehicle and controlling an anti-lock brake system (ABS) is incorporated in the bearing while rotatably supporting a vehicle wheel with respect to a suspension device. Generally known. Conventionally, in such a wheel bearing device, a sealing device is provided between an inner member and an outer member that are in rolling contact with a rolling element, and a magnetic encoder in which magnetic poles are alternately arranged in a circumferential direction is provided as the sealing device. It is integrated with. A rotational speed sensor that is arranged facing this magnetic encoder and detects a change in magnetic pole of the magnetic encoder accompanying the rotation of the wheel is mounted on the knuckle after the wheel bearing device is mounted on the knuckle constituting the suspension device. .

As an example of such a wheel bearing device, a structure as shown in FIG. 8 is known. The wheel bearing device includes an outer member 50, an inner member 51, and a plurality of balls 52 accommodated between the outer member 50 and the inner member 51. The inner member 51 includes a hub ring 53 and an inner ring 54 press-fitted into the hub ring 53.

The outer member 50 integrally has a vehicle body mounting flange 50b fixed to a knuckle (not shown) constituting a suspension device on the outer periphery, and double row outer

rolling surfaces

50a and 50a are integrally formed on the inner periphery. Has been.

The hub wheel 53 integrally has a wheel mounting flange 55 for mounting a wheel (not shown) at one end, an inner rolling surface 53a on the outer periphery, and a small diameter step extending in the axial direction from the inner rolling surface 53a. A portion 53b is formed. The inner ring 54 has an inner rolling surface 54a formed on the outer periphery, and is fixed in the axial direction by a caulking portion 53c formed by plastically deforming an end portion of the small diameter step portion 53b.

A seal member 56 is fixed to the outer end portion of the outer member 50, and the lip of the seal member 56 is in sliding contact with the base portion 55 a of the wheel mounting flange 55. On the other hand, an encoder 57 is fitted and fixed to the outer peripheral surface of the inner end portion of the inner ring 54. The encoder 57 includes a support ring 58 having an L-shaped cross section, and an encoder body 59 that is attached to and supported on the side surface of the support ring 58 over the entire circumference. In the encoder body 59, magnetic poles N and S are alternately magnetized at equal intervals in the circumferential direction.

The inner end opening of the outer member 50 is closed by a cover 60. The cover 60 is formed from a nonmagnetic plate material such as a nonmagnetic stainless steel plate, aluminum alloy plate, or high-functional resin, and is an outer peripheral cylinder that is press-fitted and fixed to the outer peripheral edge of the inner peripheral surface of the outer member 50. The portion 61, the annular flat portion 62 that faces the encoder body 59, and the bottom surface portion 63 that covers the end portion of the inner member 51 are integrally provided. The cover 60 is formed in a predetermined shape and then subjected to a demagnetization process so that the residual magnetism is preferably 3 gauss or less.

The side surface of the encoder main body 59 constituting the encoder 57 is disposed close to and opposed to the cover 60, and the detection unit of the sensor 64 is close to or abutted with the side surface of the cover 60. It is closely opposed via the cover 60. Thereby, the presence of the cover 60 prevents water, iron powder, magnetic fragments, etc. from entering between the sensor 64 and the encoder 57, thereby preventing the encoder 57 from being damaged, and the encoder body 59. It is possible to prevent regular and periodic changes in magnetic characteristics from being disturbed or deteriorated (see, for example, Patent Document 1).

However, in such a conventional wheel bearing device, the encoder 57 is disposed in close proximity to and opposed to the cover 60, the detection unit of the sensor 64 is in proximity to or in contact with the side surface of the cover 60, and the detection unit and the encoder main body 59 are covered. Because it is in close proximity to each other via 60, it is superior to the conventional seal type in terms of torque reduction and sealing performance, but because the information of the encoder 57 is read through the cover 60, the air gap increases. There was a problem.

Further, when the cover 60 is abutted against the inner peripheral step of the outer member 50 and positioned and fixed, when an excessive load or impact load is applied, the cover 60 is plastically deformed and airtightness is lowered. In addition, the encoder 57 may be pushed into contact with the ball 52 on the bearing side to be damaged.

Also known is a cover that suppresses deformation by increasing the rigidity of this type of cover. This protective cover 65 is formed into a cup shape by injection molding of a nonmagnetic synthetic resin, and as shown in FIG. 9, a cylindrical fitting portion 65a fitted inside the outer member 66, and this fitting A flange portion 65b that protrudes radially outward from the portion 65a and is in close contact with the end surface 66a of the outer member 66; a bottom portion 65c that extends radially inward from the flange portion 65b and closes the end portion of the inner ring 67; It has.

A cored bar 68 having a substantially L-shaped cross section formed by pressing from a steel plate is insert-molded at the part of the fitting portion 65a and the flange portion 65b, and the detection portion 69 of the rotation speed sensor is brought close to the outer surface of the bottom portion 65c. It is opposed to the magnetic encoder 70 through a predetermined air gap. And the rib 71 protrudes and is formed in the outer surface of the bottom part 65c except the site | part facing this. Thereby, while improving the rigidity of the protective cover 65 and suppressing deformation, the positioning accuracy can be improved and the reliability of rotation speed detection can be improved (for example, refer to Patent Document 2).

JP 2007-218426 A JP 2011-149836 A

However, since the conventional protective cover 65 is made of synthetic resin, the rib 71 can be provided on the bottom portion 65c formed of a flat surface, but it is difficult to apply the conventional cover 60 formed by pressing from a steel plate.

The present invention has been made in view of such circumstances, and has improved the positioning accuracy and improved the accuracy and reliability of rotation speed detection while increasing the rigidity of the protective cover and suppressing deformation, and the wheel bearing device. The purpose is to provide.

In order to achieve such an object, the invention according to claim 1 of the present invention includes an outer member in which a double row outer rolling surface is integrally formed on the inner periphery, and a wheel attachment for attaching a wheel to one end. A hub ring integrally having a flange and having a small-diameter step portion extending in the axial direction on the outer periphery, and at least one inner ring press-fitted into the small-diameter step portion of the hub ring. An inner member in which a double row of inner rolling surfaces facing the rolling surface is formed, and a double row of rolling members accommodated between the inner member and the outer member so as to roll freely. A moving body and a magnetic encoder externally fitted to the inner ring, and a seal is attached to an opening on the outer side of the annular space formed between the outer member and the inner member, and the inner side A cup shape was formed by pressing from a non-magnetic steel plate at the opening of In the wheel bearing device in which a protective cover is attached and the inside of the bearing is sealed, the protective cover includes a cylindrical fitting portion that is press-fitted into the inner periphery or outer periphery of the end of the outer member, and the fitting portion. A disc-shaped shielding portion extending radially inward, and a bottom portion closing the inner side end portion of the inner member from the shielding portion via a bent portion, and the shielding portion, the bent portion and the bottom portion Ribs are integrally formed by press working at the portion connecting the steps.

Thus, the outer member in which the double row outer rolling surface is integrally formed on the inner periphery, and the small-diameter step portion that has the wheel mounting flange integrally on one end and extends in the axial direction on the outer periphery. An inner member comprising a hub wheel and at least one inner ring press-fitted into a small-diameter step portion of the hub wheel, the inner member having a double-row inner rolling surface opposed to the double-row outer rolling surface on the outer periphery; A double-row rolling element housed in a freely rolling manner between the respective rolling surfaces of the inner member and the outer member, and a magnetic encoder fitted on the inner ring, and the outer member and the inner member. A seal is attached to the opening on the outer side of the annular space formed between the member and a protective cover formed in a cup shape by pressing from a non-magnetic steel plate is attached to the opening on the inner side. The wheel on the driven wheel side of the first generation to third generation structure in which the bearing interior is sealed In the bearing device, the protective cover includes a cylindrical fitting portion that is press-fitted into the inner periphery or outer periphery of the end of the outer member, a disk-shaped shielding portion that extends radially inward from the fitting portion, and the shielding member. Since the rib is integrally formed by press working at the part connecting the step between the shielding part and the bent part and the bottom part, the bottom part that closes the inner side end of the inner member from the part through the bent part, Not only can the mold be changed on a small scale, the processing is easy, but there is little change in the wall thickness and changes in the material to be added, and the strength can be increased within the range of the step. It is possible to provide a wheel bearing device in which positioning accuracy is improved and accuracy and reliability of rotation speed detection are improved while increasing rigidity and suppressing deformation.

Preferably, as in the second aspect of the present invention, when the ribs are formed in a plurality of radial directions at equal intervals in the circumferential direction, the rigidity of the protective cover becomes uniform in the circumferential direction and the fitting force is uneven. It is possible to prevent the airtightness and drop resistance from deteriorating by suppressing.

In addition, as in the third aspect of the present invention, if the ribs are arranged at least on the road surface side and the opposite road surface side, the load is applied to the protective cover on the road surface side and the opposite road surface side of the outer member when a load is applied. Therefore, by increasing the rigidity of the protective cover on the road surface side and the anti-road surface side, deformation during load application can be effectively suppressed.

According to a fourth aspect of the present invention, if the rotational speed sensor is arranged in a flat portion region of the shielding part without the rib, the rib projects to the rotational speed sensor side, The rigidity of the cover can be increased uniformly in the circumferential direction, the air gap between the protective cover and the rotation speed sensor can be reduced, and the magnetic characteristics can be improved.

Further, as in the invention described in claim 5, if the rib is formed in a circular arc shape, the press workability is improved, the durability of the mold is improved, and the cost can be reduced. it can.

Further, as in the invention described in claim 6, a bent portion having an inclination angle α1 is formed in a rectangular shape in the circumferential direction from the shielding portion inward in the radial direction, and is inclined at a corner portion of the bent portion. If a rib having an angle α2 is formed and the inclination angle α1 is set to be larger than the inclination angle α2, the rigidity of the protective cover can be increased, and muddy water or the like can be transmitted along the outer peripheral surface of the bent portion between the ribs. Is discharged, so that the sealing performance can be improved.

Further, as in the invention according to claim 7, if the plate thickness of the other portion than the shielding portion is set to be thicker than the thickness of the shielding portion, the protective cover is not increased without increasing the air gap. The rigidity of can be increased.

The wheel bearing device according to the present invention integrally has an outer member integrally formed with a double row outer rolling surface on the inner periphery, and a wheel mounting flange for mounting the wheel on one end, and on the outer periphery. A hub wheel formed with a small-diameter step portion extending in the axial direction, and at least one inner ring press-fitted into the small-diameter step portion of the hub wheel, and a double-row An inner member on which an inner rolling surface is formed, a double-row rolling element that is slidably accommodated between the rolling surfaces of the inner member and the outer member, and an outer fit to the inner ring. A magnetic encoder, and a seal is attached to the outer opening of the annular space formed between the outer member and the inner member, and the non-magnetic steel plate is attached to the inner opening. A bearing with a protective cover formed into a cup shape by pressing In the wheel bearing device in which the portion is sealed, the protective cover includes a cylindrical fitting portion that is press-fitted into the inner periphery or outer periphery of the end of the outer member, and a circle that extends radially inward from the fitting portion. A plate-shaped shielding part, and a bottom part that closes the inner side end of the inner member from the shielding part through a bent part, and a rib is provided at a portion connecting the shielding part, the bent part, and the step between the bottom part. Since it is integrally formed by press processing, it is only necessary to change the mold on a small scale, which not only simplifies the processing, but also requires less change in wall thickness and changes in the input material, and within the range of the step. It is possible to provide a wheel bearing device that can increase the strength, increase the positioning accuracy and improve the accuracy and reliability of rotation speed detection by increasing the rigidity of the protective cover and suppressing deformation.

It is a longitudinal section showing one embodiment of a wheel bearing device concerning the present invention. FIG. 2A is a front view showing a single protective cover of FIG. 1, and FIG. 2B is a longitudinal sectional view taken along line II-O-II of FIG. 1A is a front view and FIG. 1B is a longitudinal sectional view taken along line III-O-III in FIG. 1A is a front view, and FIG. 1B is a longitudinal sectional view taken along line IV-O-IV in FIG. 1A is a front view, and FIG. 1B is a longitudinal sectional view taken along the line VOV of FIG. 1A. FIG. 1A is a front view, and FIG. 1B is a longitudinal sectional view taken along line VI-O-VI in FIG. 1A is a front view, FIG. 1B is a longitudinal sectional view taken along line VII-O-VII in FIG. 1A, and FIG. FIG. 6 is a cross-sectional view taken along line AA of FIG. It is a longitudinal cross-sectional view which shows the conventional wheel bearing apparatus. It is principal part sectional drawing which shows the conventional protective cover.

An outer member integrally having a vehicle body mounting flange to be attached to the vehicle body on the outer periphery, a double row outer rolling surface formed integrally on the inner periphery, and a wheel mounting flange for mounting a wheel on one end A hub wheel integrally formed and having an inner rolling surface facing one of the outer rolling surfaces of the double row on the outer periphery, and a small-diameter step portion extending in the axial direction from the inner rolling surface, and the hub wheel An inner member formed of an inner ring that is press-fitted into a small-diameter step portion and has an inner rolling surface that is opposed to the other outer rolling surface of the double row on the outer periphery, and each of the inner member and the outer member. An annular ring formed between the outer member and the inner member, and a double row rolling element housed between the rolling surfaces of the inner ring and a magnetic encoder externally fitted to the inner ring. A seal is attached to the opening on the outer side of the space, and the opening on the inner side, In a wheel bearing device in which a protective cover formed in a cup shape by pressing from a magnetic steel plate is attached and the inside of the bearing is sealed, the protective cover is a cylindrical shape that is press-fitted into the inner periphery of the end of the outer member. A disc-shaped shielding portion extending radially inward from the fitting portion, and a bottom portion closing the inner side end portion of the inner member from the shielding portion via a bent portion. A plurality of ribs are integrally formed by press working at a portion connecting the step between the shielding portion, the bent portion, and the bottom portion, and a plurality of ribs are radially arranged in the circumferential direction.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a longitudinal sectional view showing an embodiment of a wheel bearing device according to the present invention, FIG. 2 (a) is a front view showing a single protective cover of FIG. 1, and (b) is II of (a). FIG. 3 is a modification of the protective cover of FIG. 1, (a) is a front view, and (b) is a III-O-III line of (a). FIG. 4 is another modification of the protective cover of FIG. 1, (a) is a front view, and (b) is a longitudinal section taken along line IV-O-IV of (a). 5A and 5B show another modification of the protective cover of FIG. 1, in which FIG. 5A is a front view, FIG. 5B is a longitudinal sectional view taken along line VOV in FIG. Fig. 7 is another modification of the protective cover of Fig. 1, (a) is a front view, (b) is a longitudinal sectional view taken along line VI-O-VI in (a), and Fig. 7 is a diagram of Fig. 1. In another modification of the protective cover, (a) is a front view, (b) is a longitudinal sectional view along the VII-O-VII line), (c) is a sectional view taken along line A-A of (a). In the following description, the side closer to the outer side of the vehicle when assembled to the vehicle is referred to as the outer side (left side in FIG. 1), and the side closer to the center is referred to as the inner side (right side in FIG. 1).

The wheel bearing device shown in FIG. 1 is referred to as the third generation on the driven wheel side, and is a double row rolling element that is accommodated so as to roll freely between the inner member 1 and the outer member 2, and both

members

1 and 2. (Balls) 3 and 3. The inner member 1 includes a hub ring 4 and an inner ring 5 press-fitted into the hub ring 4 through a predetermined shimiro.

The hub wheel 4 integrally has a wheel mounting flange 6 for mounting a wheel (not shown) at an end portion on the outer side, and has one (outer side) inner rolling surface 4a on the outer periphery and the inner rolling surface. A small diameter step 4b extending in the axial direction from the surface 4a is formed. In addition, hub bolts 6a are planted on the wheel mounting flange 6 in the circumferential direction.

The inner ring 5 is formed with the other (inner side) inner raceway surface 5a on the outer periphery and is press-fitted into the small-diameter stepped portion 4b of the hub wheel 4 to form a back-to-back type double row angular contact ball bearing. The inner ring 5 is fixed in the axial direction by a caulking portion 4c formed by plastically deforming the end portion of 4b. Thereby, weight reduction and size reduction can be achieved. The inner ring 5 and the rolling

elements

3 and 3 are made of high carbon chrome steel such as SUJ2, and are hardened in the range of 58 to 64 HRC up to the core part by quenching.

The hub wheel 4 is made of medium and high carbon steel containing carbon of 0.40 to 0.80 wt% such as S53C, and includes an inner rolling surface 4a and an inner side of a wheel mounting flange 6 that becomes a seal land portion of a seal 8 to be described later. The surface hardness of the base portion 6b from the base portion 6b to the small-diameter step portion 4b is set to a range of 58 to 64 HRC by induction hardening. Note that the caulking portion 4c is left with a raw surface hardness after forging. Thereby, it has sufficient mechanical strength with respect to the rotational bending load applied to the wheel mounting flange 6, the fretting resistance of the small-diameter step portion 4b serving as the fitting portion of the inner ring 5 is improved, and the minute There is no occurrence of cracks and the like, and the plastic working of the caulking portion 4c can be performed smoothly.

The outer member 2 integrally has a vehicle body mounting flange 2b to be attached to the knuckle 9 on the outer periphery, and a cylindrical pilot portion 2c fitted to the knuckle 9 is formed on the inner side of the vehicle body mounting flange 2b. The outer outer rolling surface 2a facing the inner rolling surface 4a of the hub wheel 4 and the inner outer rolling surface 2a facing the inner rolling surface 5a of the inner ring 5 are integrally formed on the inner periphery. ing. Double-

row rolling elements

3 and 3 are accommodated between these rolling surfaces and are held by the cages 7 and 7 so as to be freely rollable. The seal 8 is attached to the opening on the outer side of the annular space formed between the outer member 2 and the inner member 1, and the protective cover 14 described later is attached to the opening on the inner side. This prevents the grease sealed inside the bearing from leaking to the outside and prevents rainwater and dust from entering the bearing from the outside.

The outer member 2 is made of medium and high carbon steel containing 0.40 to 0.80 wt% of carbon such as S53C, and at least the double row outer rolling surfaces 2a and 2a have a surface hardness in the range of 58 to 64HRC by induction hardening. Has been cured.

The seal 8 is constituted by an integral seal composed of a cored bar 10 press-fitted into the inner periphery of the outer end of the outer member 2 and a seal member 11 integrally joined to the cored bar 10 by vulcanization adhesion. ing. The metal core 10 has a substantially L-shaped cross section by press working from an austenitic stainless steel plate (JIS standard SUS304 type or the like) or a cold rolled steel plate (JIS standard SPCC type or the like). On the other hand, the seal member 11 is made of a synthetic rubber such as NBR (acrylonitrile-butadiene rubber) and has a side lip 11a, a dust lip 11b, and a grease lip 11c that are in sliding contact with the outer peripheral surface of the base portion 6b. And the sealing member 11 wraps around and joins so that the outer surface of the metal core 10 may be covered, and what is called a half metal structure is comprised. Thereby, airtightness can be improved and the inside of a bearing can be protected.

In addition to the exemplified NBR, the material of the seal member 11 includes, for example, HNBR (hydrogenated acrylonitrile butadiene rubber), EPDM (ethylene propylene rubber), etc. having excellent heat resistance, and heat resistance and chemical resistance. Examples thereof include ACM (polyacrylic rubber), FKM (fluororubber), and silicon rubber, which are excellent in the above.

In addition, although the wheel bearing apparatus comprised by the double row angular contact ball bearing which used the ball for the

rolling elements

3 and 3 was illustrated here, it is not restricted to this but is comprised by the double row tapered roller bearing using a tapered roller It may be what was done. Moreover, although the wheel bearing device called the third generation in which the inner raceway surface 4a is directly formed on the outer periphery of the hub wheel 4 is illustrated, the wheel bearing device according to the present invention is not limited to such a structure, For example, although not shown, a first generation or second generation structure in which a pair of inner rings are press-fitted into a small diameter step portion of the hub ring may be used.

A support ring (pulsar ring) 12 having an L-shaped cross section is externally fitted to the inner ring 5. The support ring 12 includes a cylindrical portion 12a that is press-fitted into the outer diameter of the inner ring 5, and a standing plate portion 12b that extends radially outward from the cylindrical portion 12a, and a magnet is formed on the inner side surface of the standing plate portion 12b. The encoder 13 is integrally joined by vulcanization adhesion. This magnetic encoder 13 is a rotary encoder for detecting the rotational speed of a wheel by mixing magnetic powder such as ferrite in synthetic rubber and magnetizing magnetic poles N and S alternately at equal pitches in the circumferential direction. .

The support ring 12 is formed by press working from a ferromagnetic steel plate, for example, a ferritic stainless steel plate (JIS standard SUS430 or the like) or a rust-proof cold rolled steel plate. Thereby, the magnetic output of the magnetic encoder 13 becomes strong, and stable detection accuracy can be ensured.

In this embodiment, a sensor cap 16 is further attached to the inner side of the protective cover 14. A cylindrical outer fitting surface 18 is formed on the opening side (inner side) of the inner fitting surface 17 of the outer member 2, and the sensor cap 16 is press-fitted into the outer fitting surface 18 via a predetermined shimiro. ing. At least the outer fitting surface 18 and the inner fitting surface 17 are simultaneously processed by cutting such as grinding or turning. Preferably, after the heat treatment step by induction hardening, in the grinding step, simultaneous grinding is performed by the double row outer rolling surfaces 2a and 2a and the overall grindstone.

Thus, if the outer fitting surface 18 and the inner fitting surface 17 are processed at the same time, the accuracy of the roundness, the coaxiality, etc. of each fitting surface 18 and 17 will improve, and the airtightness of a fitting part will be improved. In addition, the number of processing steps can be reduced by simultaneous cutting, and the cost can be reduced. Further, since the outer fitting surface 18 is formed on the inner side of the inner fitting surface 17 via the stepped portion 17a, the press-fitting stroke of the protective cover 14 is minimized to improve the assembly workability and the press-fitting. The deformation of the protective cover 14 in the process can be prevented, and the reliability of the product can be improved.

The sensor cap 16 is formed in a cup shape from a cold-rolled steel plate by pressing and is subjected to a rust prevention treatment such as cationic electrodeposition coating, and is pressed into the outer fitting surface 18 of the outer member 2. A fitting portion 16a, a flange portion 16b that overlaps and extends radially outward from the fitting portion 16a, and is in close contact with the inner end face 2d of the outer member 2, and the outer member 2 from the flange portion 16b. And a bottom portion 16c for closing the opening on the inner side. An insertion hole 19 is formed in the bottom portion 16 c of the sensor cap 16 at a horizontal position corresponding to the magnetic encoder 13, and a rotation speed sensor 24 described later is inserted into the insertion hole 19. Thus, since the sensor cap 16 includes the flange portion 16b that is in close contact with the end surface 2d of the outer member 2, the rigidity can be increased and the positioning accuracy of the rotation speed sensor 24 can be improved, and the insertion hole 19 can be improved. Is formed in a horizontal position, and if the rotational speed sensor 24 is mounted in the fitting insertion hole 19, even when the outer member 2 and the inner member 1 are relatively inclined due to a lateral load from the wheel, The air gap fluctuation between the rotation speed sensor 24 and the magnetic encoder 13 can be suppressed, and stable detection accuracy can be obtained.

Further, a fixing nut 21 is fixed to the perforation 20 formed on the center side of the sensor cap 16 by caulking. The fixing nut 21 is caulked and fixed to the bearing inner side (outer side) of the bottom portion 16 c of the sensor cap 16. The rotation speed sensor 24 inserted into the insertion hole 19 of the sensor cap 16 is fixed by fastening the mounting bolt 23 to the fixing nut 21 via the mounting member 22. In addition to this, the fixing method of the fixing nut 21 may be, for example, welding, adhesion, press-fitting, or the like. Thus, in this embodiment, since the fixing nut 21 is fixed to the bearing inner side of the bottom portion 16c of the sensor cap 16, the fixing nut 21 is pulled into the inner surface of the bottom portion 16c by fastening the mounting bolt 23. Dropping can be prevented only by simple caulking and fixing of the fixing nut 21.

The rotation speed sensor 24 is an IC in which a magnetic detecting element such as a Hall element, a magnetoresistive element (MR element) or the like that changes characteristics according to the flow direction of magnetic flux and a waveform shaping circuit that adjusts the output waveform of the magnetic detecting element are incorporated. The anti-lock brake system of the motor vehicle which consists of these etc. and detects the rotational speed of a wheel and controls the rotation speed is comprised.

The protective cover 14 attached to the inner side end of the outer member 2 is formed in a cup shape by press working from a nonmagnetic austenitic stainless steel plate (JIS standard SUS304 system or the like). As shown in an enlarged view in FIG. 2, the protective cover 14 includes a cylindrical fitting portion 14a that is press-fitted into the inner periphery of the end of an outer member (not shown), and a reduced diameter portion from the fitting portion 14a. An end portion on the inner side of an inner member (not shown) via a disk-shaped shielding portion 14c extending radially inward via 14b and a bent portion 14d bulging outward from the shielding portion 14c And a bottom portion 14e for closing. In this example, the protective cover 14 is formed of an austenitic stainless steel plate so that the sensing performance of the rotational speed sensor 24 is not adversely affected. When the detection is not performed, for example, a cold rolled steel sheet may be subjected to a rust prevention treatment such as plating.

Further, an elastic member (seal member) 15 made of synthetic rubber such as NBR is integrally joined to the outer peripheral surface of the reduced diameter portion 14b by vulcanization adhesion. The elastic member 15 protrudes from the side surface of the shielding portion 14c of the protective cover 14 to the inner side so as not to interfere with a rotation speed sensor 24 described later, and protrudes radially outward from the outer diameter of the fitting portion 14a. An annular protrusion 15a is provided. Then, the annular protrusion 15a of the elastic member 15 is elastically deformed and pressure-bonded to the fitting surface of the outer member 2 when the protective cover 14 is fitted, thereby forming a half metal structure and improving the airtightness of the fitting portion 14a. .

The rotational speed sensor 24 is in close proximity to or in contact with the shielding portion 14c of the protective cover 14, and the rotational speed sensor 24 and the magnetic encoder 13 are arranged to face each other with a predetermined air gap (axial clearance) through the protective cover 14. (See FIG. 1). Such a stepped shape increases the rigidity of the protective cover 14, can suppress deformation during press-fitting and deformation during input of a large bearing load, and is excellent in corrosion resistance and can improve durability over a long period of time. .

Here, in the protective cover 14, ribs 25 that extend radially are integrally formed by pressing at a portion that connects the steps of the shielding portion 14c, the bent portion 14d, and the bottom portion 14e. In the present embodiment, a plurality of ribs 25 are formed at equal intervals in the circumferential direction (here, four locations). Thereby, the rigidity of the protective cover 14 is improved, and it is possible to prevent the fitting force from being biased and to prevent the airtightness and drop resistance from being lowered. In addition, since the rib 25 is only provided at the step portion of the protective cover 14, not only a small mold change is required, but not only the processing becomes easy, but also the change in the thickness and the change of the material to be input can be reduced. Provided is a wheel bearing device that can increase the strength within the range of the step, increase the rigidity of the protective cover 14 and suppress deformation, and improve the positioning accuracy and the accuracy and reliability of rotation speed detection. can do.

FIG. 3 shows a modified example of the protective cover 14 described above. The protective cover 26 is formed in a cup shape by press working from a nonmagnetic austenitic stainless steel plate. In addition, only the shape is basically different from the protective cover 14 described above, and other parts having the same function are denoted by the same reference numerals, and redundant description is omitted.

The protective cover 26 is a cylindrical fitting portion 14a that is press-fitted into the inner periphery of the end of an outer member (not shown), and a circle that extends radially inward from the fitting portion 14a via the reduced diameter portion 14b. A plate-shaped shielding portion 26a and a bottom portion 26c that closes an inner side end portion of an inner member (not shown) from the shielding portion 26a through a bent portion 26b are provided. And the circular recessed part 26d which bulges to an outer side is formed in the center part of this bottom part 26c.

Here, ribs 27 extending radially are integrally formed by pressing at a portion connecting the steps of the shielding portion 26a, the bent portion 26b, and the bottom portion 26c. In the present embodiment, in order to make the rigidity of the protective cover 26 uniform in the circumferential direction, a plurality of ribs 27 (four in this case) are formed in the circumferential direction. And the rotational speed sensor 24 is arrange | positioned at the flat part area | region of the shielding part 26a which does not have the rib 27, as shown to Fig.3 (a). Accordingly, in the configuration in which the rib 27 protrudes toward the rotational speed sensor 24 (inner side), the rigidity of the protective cover 26 can be increased uniformly in the circumferential direction, and the air between the protective cover 26 and the rotational speed sensor 24 can be increased. A gap can be made small and a magnetic characteristic can be improved.

Next, another modification of the protective cover 14 will be shown. The protective cover 28 shown in FIG. 4 is formed in a cup shape by press working from a nonmagnetic austenitic stainless steel plate. It should be noted that, basically, the shape is different from that described above, and parts having the same function are denoted by the same reference numerals and redundant description is omitted.

The protective cover 28 includes a cylindrical fitting portion 14a that is press-fitted into an inner fitting surface of an outer member (not shown), and a disc that extends radially inward from the fitting portion 14a via a reduced diameter portion 14b. -Shaped shielding portion 28a, a bottom portion 26c for closing the inner side end portion of the inner member (not shown) from the shielding portion 28a via the bent portion 28b, and a bulge on the outer side at the center portion of the bottom portion 26c A concave portion 26d is provided. And the rib 29 extended in the part which connects the level | step difference of the shielding part 28a, the bending part 28b, and the bottom part 26c is integrally formed by press work.

In this embodiment, the bent portion 28b and the rib 29 are formed with different inclination angles. Specifically, a bent portion 28b having an inclination angle α1 from the shielding portion 28a radially inward is formed in a rectangular shape having a predetermined width in the circumferential direction, and an inclination angle α2 is formed at a corner portion of the bent portion 28b. Four ribs 29 are formed (α1> α2). Thereby, like the above-mentioned thing, while the rigidity of the protective cover 28 can be improved, since muddy water etc. are discharged | emitted along the outer peripheral surface of the bending part 28b between the ribs 29, a sealing performance can be improved. . In particular, when the bent portion 28b is mounted on the road surface side and the anti-road surface side, a further effect can be expected.

The protective cover 30 shown in FIG. 5 is formed in a cup shape by press working from a nonmagnetic austenitic stainless steel plate. It should be noted that basically the structure is partially different from that described above, and parts having the same function are denoted by the same reference numerals and redundant description is omitted.

The protective cover 30 includes a cylindrical fitting portion 30a that is press-fitted into an inner fitting surface of an outer member (not shown), and a disk-like shape that extends radially inward from the fitting portion 30a via a reduced diameter portion 30b. And a bottom portion 30d for closing the inner side end portion of the inner member (not shown) from the shielding portion 14c through the bent portion 30c. And the rib 25 extended radially is integrally formed by the press work in the part which connects the level | step difference of the shielding part 14c, the bending part 30c, and the bottom part 30d. Here, the plate thickness t1 of other parts other than the shielding portion 14c is set to be thicker than the plate thickness t2 of the shielding portion 14c (t1> t2). Thereby, the rigidity of the protective cover 30 can be increased without increasing the air gap.

The protective cover 31 shown in FIG. 6 is formed in a cup shape by press working from a nonmagnetic austenitic stainless steel plate. It should be noted that, basically, only the fitting direction of the protective cover 14 is different from that described above, and portions having the same function are denoted by the same reference numerals and redundant description is omitted.

The protective cover 31 includes a cylindrical fitting portion 14a that is press-fitted into an inner fitting surface of an outer member (not shown), and a disc that extends radially inward from the fitting portion 14a via a reduced diameter portion 14b. And a bottom portion 14e that closes an inner side end of an inner member (not shown) from the shielding portion 14c through a bent portion 14d. And the rib 32 extended radially is integrally formed by the press work in the part which connects the level | step difference of the shielding part 14c, the bending part 14d, and the bottom part 14e, and this rib 32 is arrange | positioned at least on the road surface side and the anti-road surface side. As a result, when a load is applied, a load is applied in the direction of the road surface side and the anti-road surface side of the outer member. Therefore, by increasing the rigidity of the road surface side and the anti-road surface side, deformation during the load application is effectively suppressed. be able to.

The protective cover 33 shown in FIG. 7 is formed in a cup shape by press working from a non-magnetic austenitic stainless steel plate. It should be noted that, basically, only a part of the shape is different from that described above, and parts having the same function are denoted by the same reference numerals and redundant description is omitted.

The protective cover 33 is a cylindrical fitting portion 14a that is press-fitted into an inner fitting surface of an outer member (not shown), and a disk shape that extends radially inward from the fitting portion 14a via a reduced diameter portion 14b. A shielding portion 14c, and a bottom portion 14e that closes an inner side end portion of an inner member (not shown) from the shielding portion 14c through a bent portion 14d. Then, radially extending ribs 34 are integrally formed by pressing at a portion connecting the steps of the shielding portion 14c, the bent portion 14d, and the bottom portion 14e. As shown in FIG. 7C, the rib 34 has a predetermined cross-sectional shape. It is composed of a circular arc surface (curve) having a radius of curvature r. Thereby, the press workability is improved, the durability of the mold is improved, and the cost can be reduced.

The embodiment of the present invention has been described above, but the present invention is not limited to such an embodiment, and is merely an example, and various modifications can be made without departing from the scope of the present invention. Of course, the scope of the present invention is indicated by the description of the scope of claims, and further, the equivalent meanings described in the scope of claims and all modifications within the scope of the scope of the present invention are included. Including.

The wheel bearing device according to the present invention can be applied to a wheel bearing device on the driven wheel side of the first generation to third generation structure.

DESCRIPTION OF SYMBOLS 1 Inner member 2 Outer member 2a Outer rolling surface 2b Car body mounting flange 2c Pilot part 2d Inner side end surface 3 of outer member Rolling element 4 Hub wheel 4a, 5a Inner rolling surface 4b Small diameter step part 4c Clamping part 5 Inner ring 6 Wheel mounting flange 6a Hub bolt 6b Base 7 on the inner side of the wheel mounting flange Cage 8 Seal 9 Knuckle 10 Core 11 Seal member 11a Side lip 11b Dustrip 11c Grease lip 12 Support ring 12a Cylindrical part 12b Standing plate part 13 Magnetic encoder 14, 26, 28, 30, 31, 33 Protective cover 14a, 16a, 30a Fitting part 14b, 30b Reduced diameter part 14c, 26a, 28a Shield part 14d, 26b, 28b, 30c Bent part 14e, 16c, 26c 30d, bottom 15 elastic member 15a, annular protrusion 16, sensor cap 16b, flange 17 outside Member inner fitting surface 17a Step portion 18 Outer member fitting surface 19 Fitting insertion hole 20 Drilling hole 21 Fixing nut 22 Mounting member 23 Mounting bolt 24 Rotational speed sensor 25, 27, 29, 32, 34 Rib 26d Recess 50 Outside Side member 50a Outer rolling surface 50b Car body mounting flange 51 Inner member 52 Ball 53 Hub wheels 53a, 54a Inner rolling surface 53b Small diameter step portion 53c Clamping portion 54 Inner ring 55 Wheel mounting flange 55a Base 56 Seal member 57 Encoder 58 Support Ring 59 Encoder main body 60 Cover 61 Outer cylindrical part 62 Annular flat part 63 Bottom face part 64 Sensor 65 Protective cover 65a Fitting part 65b Gutter part 65c Bottom part 66 Outer member 66a End face 67 of outer member Inner ring 68 Core metal 69 Rotational speed sensor Detecting section 70 magnetic encoder 71 rib r radius of curvature t1 rib thickness t2 other than shielding section shielding Thickness α1 of shielding part Inclination angle α2 of bending part Inclination angle of rib

Claims

An outer member in which a double row outer rolling surface is integrally formed on the inner periphery;
A hub wheel integrally having a wheel mounting flange for mounting a wheel at one end, and having a small-diameter step portion extending in the axial direction on the outer periphery, and at least one inner ring press-fitted into the small-diameter step portion of the hub ring; An inner member in which a double row inner rolling surface facing the outer rolling surface of the double row is formed on the outer periphery,
A double row rolling element housed movably between the rolling surfaces of the inner member and the outer member;
A magnetic encoder fitted on the inner ring,
A seal is attached to the opening on the outer side of the annular space formed between the outer member and the inner member,
In the wheel bearing device in which a protective cover formed in a cup shape by pressing from a non-magnetic steel plate is attached to the opening on the inner side and the inside of the bearing is sealed,
The protective cover includes a cylindrical fitting portion that is press-fitted into the inner periphery or outer periphery of the end portion of the outer member, a disk-shaped shielding portion that extends radially inward from the fitting portion, and the shielding portion. A bottom portion that closes an end portion on the inner side of the inner member through a bent portion, and
A bearing device for a wheel, characterized in that a rib is integrally formed by pressing at a portion connecting the shielding portion, the bent portion, and the step between the bottom portion.
The wheel bearing device according to claim 1, wherein a plurality of the ribs are radially formed in a circumferentially equidistant manner.
The wheel bearing device according to claim 1 or 2, wherein the ribs are arranged at least on a road surface side and an anti-road surface side.
The wheel bearing device according to any one of claims 1 to 3, wherein the rotational speed sensor is arranged in a flat part region of the shielding part without the rib.
The wheel bearing device according to any one of claims 1 to 4, wherein the rib is formed in an arc shape in cross section.
A bent portion having an inclination angle α1 is formed in a radial direction from the shielding portion inward in the radial direction, and a rib having an inclination angle α2 is formed at a corner portion of the bent portion, and the inclination angle α1 is formed. The wheel bearing device according to claim 1, wherein is set to be larger than the inclination angle α2.
The wheel bearing device according to claim 1, wherein a plate thickness of a portion other than the shielding portion is set to be thicker than a thickness of the shielding portion.