JP2012188090A - Bearing device for wheel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a bearing device for a wheel for protecting a magnetic encoder by increasing airtightness of a fitting part between a protective cover and an external member, and increasing reliability by firmly fixing and positioning the protective cover.SOLUTION: The protective cover 10 is formed in a cup shape by pressing a nonmagnetic austenite stainless steel sheet. The protective cover includes: a fitting part 10a press-fitted to the inner peripheral surface of the end part of the external member 2 with a predetermined interference; a disk-like blocking part 10b which extends radially inward from the fitting part 10a and allows the inner side side-surface thereof to be brought close to or into contact with a rotating speed sensor 15; and a bottom part 10d which closes the inner side end of an internal member 1 from the blocking part 10b through a step part. The inner side end of the fitting surface between the external member 2 and the protective cover 10 is formed in a plurality of circumferential joint parts 17 by arc welding.

Description

  The present invention relates to a wheel bearing device equipped with a protective cover for rotatably supporting a wheel of an automobile or the like and sealing the inside of the bearing.

  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. .

  A structure as shown in FIG. 8 is known as an example of such a wheel bearing device. 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 for mounting a wheel (not shown) at one end portion, and an inner rolling surface 53a and a small-diameter step portion 53b extending in the axial direction from the inner rolling surface 53a are formed on the outer periphery. Has been. 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.

  An encoder 55 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 56 having an L-shaped cross section, and an encoder body 57 that is attached and supported on the side surface of the support ring 56 over the entire circumference. The encoder body 57 has magnetic poles N and S alternately magnetized at equal intervals in the circumferential direction.

  An inner end opening of the outer member 50 is closed by a cover 58. The cover 58 is formed of a nonmagnetic plate material such as a nonmagnetic stainless steel plate, aluminum alloy plate, or high-functional resin, and is a cylindrical portion that is press-fitted and fixed to the inner peripheral surface of the outer member 50 at the outer peripheral edge portion. 59 and a flat plate portion 60 bent inward in the radial direction from the cylindrical portion 59. The flat plate portion 60 is closely opposed to the encoder main body 57 via a minute gap 61, and the detection portion of a sensor (not shown) is brought close to or in contact with the side surface of the cover 58. Are opposed to each other through a cover 58.

  Here, a non-contact portion 62 is formed over the entire circumference at the inner end portion in the axial direction of the cylindrical portion 59 constituting the cover 58. The non-contact portion 62 is formed in a partial conical cylinder shape that is inclined by α in a direction in which the diameter decreases as it goes inward in the axial direction, and has an outer diameter smaller than the inner diameter D1 of the inner end portion of the outer member 50. D2 (D1> D2). Thereby, the presence of the cover 58 can prevent water, iron powder, magnetized debris, etc. from entering between the sensor and the encoder 55 to prevent damage to the sensor and the encoder 55, and the cylindrical portion 59. Even in a state in which the cover 58 is press-fitted, the outer peripheral surface of the non-contact portion 62 does not contact the inner peripheral surface of the outer member 50, and deformation of the cover 58 can be prevented (see, for example, Patent Document 1). .

JP 2010-190421 A

  In such a conventional wheel bearing device, when the cover 58 is press-fitted into the outer member 50, the non-contact portion 62 is formed over the entire circumference. The outer peripheral surface of the non-contact portion 62 is not in contact with the inner peripheral surface of the outer member 50, and the cover 58 can be prevented from being deformed. However, since the fitting portion is only the cylindrical portion 59 that is press-fitted into the inner peripheral surface of the end portion of the outer member 50, there is a possibility that the tight contact area of the fitting portion is reduced and the sealing performance is lowered. For this reason, it is conceivable to improve the airtightness of the fitting portion by vulcanizing and bonding rubber to the non-contact portion 62. However, this is not preferable because the manufacturing cost of the cover 58 increases.

  The present invention has been made in view of such circumstances, and enhances the airtightness of the fitting portion between the protective cover and the outer member to protect the magnetic encoder, and strengthens the positioning and fixing of the protective cover for reliability. An object of the present invention is to provide a wheel bearing device with improved performance.

In order to achieve such an object, the invention according to claim 1 of the present invention has a vehicle body mounting flange integrally attached to the knuckle constituting the suspension device on the outer periphery, and double row outer rolling on the inner periphery. A hub wheel having an integrally formed outer member, a wheel mounting flange for mounting a wheel at one end, and a small-diameter step portion extending in the axial direction on the outer periphery, and the hub wheel An inner member comprising at least one inner ring press-fitted into a small-diameter step portion, and having an outer periphery formed with a double-row inner rolling surface opposite to the double-row outer rolling surface, the inner member and the outer member A plurality of rolling elements housed in a freely rolling manner between the rolling surfaces of the outer member, a seal is attached to an outer end of the outer member, and an inner member of the outer member A protective cover is attached to the end on the side, the outer member and the inner part In the wheel bearing device in which the opening of the annular space formed by the sealing member is sealed, the protective cover is fitted to the end portion of the outer member, and radially inward from the fitting portion. A disc-shaped shielding part, the rotation speed sensor approaching or abutting on the inner side surface, and a bottom part closing the inner side end of the inner member from the shielding part via a step part. In addition, the outer member and the protective cover are joined by welding, and the joint is sealed by the welding.
They are joined together.

  Thus, in the inner ring rotation type wheel bearing device, the protective cover is fitted to the end portion of the outer member, and extends radially inward from the fitting portion. A disc-shaped shielding portion that is close to or abuts on the side surface on the side, and a bottom portion that covers the inner side end of the inner member from the shielding portion via a step portion, and the outer member and the protective cover Since the joint is sealed by welding, the airtightness of the fitting surface between the outer member and the protective cover can be improved over a long period of time and the vehicle is running. Even if a vibration or impact load is applied, the protective cover can be reliably prevented from coming out.

  Preferably, as in the invention described in claim 2, if the protective cover is formed from a steel plate by pressing, the productivity is high and the cost can be reduced.

  Further, preferably, as in the invention described in claim 3, if a magnetic encoder is fitted on the inner ring and the protective cover is formed of a nonmagnetic austenitic stainless steel plate, Rigidity is increased, deformation due to flying stones and the like can be suppressed, durability is improved over a long period of time with excellent corrosion resistance, and desired detection accuracy is obtained without affecting the flow path of magnetic flux.

  Further, as in the invention described in claim 4, if the detection surface of the magnetic encoder and the large end surface of the inner ring are substantially flush or set so as to slightly protrude to the inner side from the large end surface. The air gap can be easily adjusted, and the air gap can be aimed at smaller.

  Further, as in the invention according to claim 5, the fitting portion of the protective cover is formed in a cylindrical shape and is press-fitted into the inner peripheral surface of the end portion of the outer member, and the outer periphery of the end portion of the outer member. If a pilot portion serving as a fitting surface with the knuckle is formed and a small-diameter portion is formed on the end surface side of the pilot portion, the pilot can be used even if the small-diameter portion of the outer member is deformed due to the thermal effect of welding. It does not reach the department.

  In addition, as in the invention described in claim 6, if the joint between the outer member and the protective cover is formed over the entire circumference, the airtightness of the fitting surface between the outer member and the protective cover Therefore, it is not necessary to secure the fitting area, and at least the fitting accuracy can be maintained without increasing the press-fitting squeeze, so the width of the fitting portion can be made as much as possible. The bearing portion can be made compact.

  Further, as in the invention described in claim 7, if an annular projection is formed at the end of the outer member and the fitting portion of the protective cover is attached to the annular projection and welded, the protective cover Even if the plate thickness is reduced, heat from welding is less likely to enter the protective cover than the outer member, and the molten state of both can be made equal.

  In addition, if the welding is laser welding as in the invention described in claim 8, not only high-speed welding is possible, but deep penetration welding is possible, and the thermal influence is small, and deformation accompanying it is also possible. Since there are few, reliability can be improved.

  Further, as in the invention of claim 9, if the welding is brazing, an alloy having a melting point lower than that of the outer member or the protective cover is used, and the base material is joined without melting, so that the base material is melted. Therefore, thermal deformation can be reliably suppressed and desired accuracy can be ensured.

  If the welding is TIG welding as in the invention described in claim 10, the electrode is tungsten having a high melting point, and therefore the electrode does not decrease over a long period of time, the productivity is improved, and a spark is obtained. Does not scatter, which can prevent adverse effects on the surrounding environment.

  Further, as in the invention described in claim 11, if the surface of the joint by welding is coated or rust-proof, oxidation of the joint can be prevented and the reliability can be improved.

  A wheel bearing device according to the present invention has a vehicle body mounting flange integrally attached to a knuckle constituting a suspension device on an outer periphery, and an outer side in which a double row outer rolling surface is integrally formed on an inner periphery. And a hub wheel integrally having a wheel mounting flange for mounting a wheel at one end thereof and having a small-diameter step portion extending in the axial direction on the outer periphery, and at least one press-fitted into the small-diameter step portion of the hub ring An inner member formed of two inner rings and formed on the outer periphery with a double row inner rolling surface facing the outer row rolling surface of the double row, and between the respective rolling surfaces of the inner member and the outer member A plurality of rolling elements housed in a freely rotatable manner, and a seal is attached to the outer end of the outer member, and a protective cover is attached to the inner end of the outer member. An annular space formed by the outer member and the inner member. In the wheel bearing device in which the mouth is sealed, the protective cover has a fitting portion attached to an end portion of the outer member, and extends radially inward from the fitting portion. A disc-shaped shielding portion that is close to or abuts on the side surface on the side, and a bottom portion that closes an inner side end portion of the inner member from the shielding portion via a stepped portion, and the outer member; Since the protective cover is joined by welding and the joint is sealed by welding, the airtightness of the fitting surface between the outer member and the protective cover can be improved over a long period of time, It is possible to reliably prevent the protective cover from coming out even when a vibration or impact load is applied during traveling.

It is a longitudinal section showing one embodiment of a wheel bearing device concerning the present invention. It is a principal part enlarged view which shows the detection part of FIG. It is a principal part enlarged view which shows the modification of FIG. It is sectional drawing which shows the other modification of FIG. It is a principal part enlarged view which shows the modification of FIG. It is a principal part enlarged view which shows the modification of FIG. It is a principal part enlarged view which shows the modification of FIG. It is a longitudinal cross-sectional view which shows the conventional wheel bearing apparatus.

  An outer member that integrally has a vehicle body mounting flange to be attached to a knuckle constituting a suspension device on the outer periphery, and an outer member in which a double row outer rolling surface is integrally formed on the inner periphery, and a wheel on one end A hub wheel having a wheel mounting flange integrally formed and having an inner rolling surface facing the outer rolling surface 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 an inner member formed of an inner ring press-fitted into the small diameter step portion of the hub wheel and formed with the other inner rolling surface facing the outer rolling surface of the double row, and the inner member and the outer side. A double-row rolling element housed between the rolling surfaces of the member so as to be freely rollable, and a magnetic encoder externally fitted to the inner ring, and plastically deforming an end of the small-diameter step portion of the hub ring. The inner ring is in a state where a predetermined bearing preload is applied by the caulking portion formed by The shaft is fixed in the axial direction with respect to the hub wheel, a seal is attached to the outer end of the outer member, and a protective cover is attached to the inner end of the outer member. In the wheel bearing device in which the opening of the annular space formed by the member and the inner member is sealed, the protective cover is formed into a cup shape by pressing from a nonmagnetic austenitic stainless steel plate, and the outer member A fitting part that is press-fitted into the inner peripheral surface of the end part via a predetermined shimiro, and a disk-like shape that extends radially inward from the fitting part so that the rotational speed sensor approaches or contacts the inner side surface And a bottom portion for closing the inner side end portion of the inner member from the shielding portion through a step portion, and the inner side end portion of the fitting surface of the outer member and the protective cover is By arc welding There is a junction.

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 is an enlarged view of a main part showing a detection part of FIG. 1, and FIG. 3 is a main part showing a modification of FIG. FIG. 4 is a sectional view showing another modification of FIG. 2, FIG. 5 is an enlarged view of a main part showing a modification of FIG. 4, and FIG. 6 is an enlarged main part showing a modification of FIG. FIG. 7 is an enlarged view of a main part showing a modification of FIG. 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).

  This wheel bearing device is for a driven wheel referred to as a third generation, and is a double row rolling element housed in a freely rollable manner between the inner member 1, outer member 2, and both members 1,2. (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 outer member 2 is made of medium and high carbon steel containing 0.40 to 0.80 wt% of carbon such as S53C, and integrally has a vehicle body mounting flange 2b for mounting to a knuckle (not shown) on the outer periphery. Double row outer rolling surfaces 2a, 2a are integrally formed. These double-row outer raceway surfaces 2a and 2a are formed with a hardened layer having a surface hardness of 58 to 64 HRC by induction hardening.

  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 hub bolts 6a are implanted at circumferentially equidistant positions of the wheel mounting flange 6. Yes. Moreover, the inner side rolling surface 4a which opposes one (outer side) of the said double row outer side rolling surface 2a, 2a and the small diameter step part 4b extended in an axial direction from this inner side rolling surface 4a are formed in outer periphery. Yes. On the other hand, the inner ring 5 is formed on the outer periphery with an inner rolling surface 5a facing the other (inner side) of the double row outer rolling surfaces 2a, 2a, and a small-diameter step portion 4b of the hub wheel 4 via a predetermined shimoshiro. It is press-fitted. The inner ring 5 is fixed in the axial direction in a state where a predetermined bearing preload is applied by a crimping portion 7 formed by plastically deforming an end portion of the small-diameter stepped portion 4b of the hub wheel 4 radially outward. .

  Between the double row outer rolling surfaces 2a, 2a of the outer member 2 and the double row inner rolling surfaces 4a, 5a facing these, the double row rolling elements 3, 3 are respectively accommodated, and the cage 8 , 8 are held so as to roll freely. A seal 9 is attached to the outer opening of the annular space formed between the outer member 2 and the inner member 1, and the magnetic encoder 14 and the protection are provided to the inner opening. A cover 10 is attached to prevent leakage of lubricating grease sealed in the bearing and prevent rainwater, dust, and the like from entering the bearing from the outside.

  In addition, although the wheel bearing apparatus comprised by the double row angular contact ball bearing which used the ball for the rolling element 3 was illustrated here, it is not restricted to this, The double row tapered roller bearing which used the tapered roller for the rolling element 3 It may consist of. In addition, here, a third generation structure in which the inner rolling surface 4a is formed directly on the outer periphery of the hub wheel 4 is illustrated, but although not shown, a pair of inner rings are press-fitted and fixed to the small-diameter step portion of the hub wheel. It may be a first generation or second generation structure.

  The hub wheel 4 is made of medium and high carbon steel containing 0.40 to 0.80 wt% of carbon such as S53C, and extends from the inner raceway surface 4a to the small diameter step portion 4b from the base portion 6b on the inner side of the wheel mounting flange 6. Thus, the surface hardness is set to a range of 58 to 64 HRC by induction hardening. The caulking portion 7 is an unquenched portion with the surface hardness after forging. This facilitates the caulking process, prevents the occurrence of microcracks during the process, improves not only the wear resistance of the base part 6b serving as the seal land part of the seal 9, but also loads the wheel mounting flange 6. Therefore, the durability of the hub wheel 4 is improved. The inner ring 5 and the rolling element 3 are made of high carbon chrome bearing steel such as SUJ2, and are hardened in the range of 58 to 64 HRC to the core portion by quenching.

  The seal 9 is an integrated seal composed of a core metal 11 press-fitted into the inner periphery of the outer side end portion of the outer member 2 through a predetermined shimiro and a seal member 12 joined to the core metal 11. It is configured. The core metal 11 is formed by press-working a cold-rolled steel plate (JIS standard SPCC system or the like).

  On the other hand, the sealing member 12 is made of synthetic rubber such as nitrile rubber and is integrally joined to the core metal 11 by vulcanization adhesion. The seal member 12 is formed to be inclined outward in the radial direction, and has a side lip 12a slidably contacting a side surface on the inner side of the wheel mounting flange 6 with a predetermined axial squeeze, and a base portion 6b having a cross section formed in an arc shape. The side lip 12b is slidably contacted with a predetermined axial squeeze, and the grease lip 12c is formed to be inclined toward the inner side of the bearing and is slidably contacted with a predetermined radial squeeze.

  A support ring 13 having an L-shaped cross section is fitted on the inner ring 5. The support ring 13 includes a cylindrical portion 13a that is press-fitted into the outer diameter of the inner ring 5, and a standing plate portion 13b that extends radially outward from the cylindrical portion 13a, and a magnet is formed on the inner side surface of the standing plate portion 13b. The encoder 14 is integrally joined by vulcanization adhesion. In the magnetic encoder 14, magnetic powder such as ferrite is mixed in an elastomer such as synthetic rubber, and the magnetic poles N and S are magnetized alternately at equal pitches in the circumferential direction.

  Further, the support ring 13 is formed by pressing 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 (JIS standard SPCC or the like). Is formed. As a result, it is possible to prevent the support ring 13 from rusting and to increase the magnetic output of the magnetic encoder 14 to ensure stable detection accuracy.

  The protective cover 10 mounted on the inner side end of the outer member 2 is formed into a cup shape by press working from a nonmagnetic austenitic stainless steel plate (such as JIS 304 SUS standard). As shown in an enlarged view in FIG. 2, the protective cover 10 includes a cylindrical fitting portion 10a that is press-fitted into the inner periphery of the end of the outer member 2, and a circle that extends radially inward from the fitting portion 10a. A plate-shaped shielding portion 10b and a bottom portion 10d that closes the inner side end of the inner member 1 from the shielding portion 10b through the cylindrical portion 10c are provided. The detection unit 16 of the rotation speed sensor 15 is brought close to or in contact with the shielding unit 10 b of the protective cover 10, and the detection unit 16 and the magnetic encoder 14 pass through the protective cover 10 to have a predetermined air gap (axial clearance). Are arranged opposite each other. Such a stepped shape increases the rigidity of the protective cover 10 and can suppress deformation due to flying stones, etc., and since the protective cover 10 is a non-magnetic material, it does not affect the flow path of magnetic flux and has excellent corrosion resistance. The durability can be improved over a period of time.

  Here, in this embodiment, the outer member 2 and the fitting part 10a of the protective cover 10 press-fitted into the outer member 2 are joined by welding. Specifically, end portions on the inner side of the fitting surface of the outer member 2 and the protective cover 10 are formed into a plurality of joint portions 17 in the circumferential direction by arc welding. As a result, the airtightness of the fitting surface between the outer member 2 and the protective cover 10 can be improved over a long period of time, and the protective cover 10 can be pulled out even when a vibration or impact load is applied during traveling. It can be surely prevented. At the time of welding, it is possible to prevent the welded portion from being oxidized by performing welding while spraying a shielding gas on the welded portion, or by performing coating or rust prevention treatment after welding.

  Further, in the present embodiment, the inner side end surface 2c of the outer member 2 is formed so as to protrude from the inner end 5 by a step L1 to the inner side, and the shielding portion 10b of the protective cover 10 and the outer member are formed. The end face 2c of 2 and the detection face of the magnetic encoder 14 and the large end face 5b of the inner ring 5 are set to be substantially flush with each other. As a result, the protective cover 10 can be prevented from coming into contact with the inner ring 5. Further, if the detection surface of the magnetic encoder 14 and the large end surface 5b of the inner ring 5 are substantially flush or set so as to slightly protrude toward the inner side from the large end surface 5b, the protective cover 10 is attached to the outer member 2. The end surface 2c can be positioned and fixed with high accuracy, and the support ring 13 can be positioned and fixed with high accuracy based on the large end surface 5b of the inner ring 5. As a result, the air gap can be easily adjusted and the detection accuracy can be improved. Can be increased.

  FIG. 3 is a modification of the protective cover 10 described above. The protective cover 18 is basically different in shape from the protective cover 10 described above, and the same components are denoted by the same reference numerals and detailed description thereof is omitted.

  The protective cover 18 is formed in a cup shape by press working from a non-magnetic austenitic stainless steel plate, and has a cylindrical fitting portion 18a that is press-fitted into the outer periphery of the end portion of the outer member 19, and the fitting portion 18a. A disc-shaped shielding portion 18b extending inward in the radial direction and in close contact with the end surface 2c on the inner side of the outer member 19, and an inner side of the inner member 1 from the shielding portion 18b via the reduced diameter portion 18c. And a bottom portion 10d that closes the end portion. Such a stepped shape increases the rigidity as in the protective cover 10 described above, can suppress deformation due to flying stones, etc., and since the protective cover 18 is non-magnetic, it does not affect the flow path of magnetic flux, and also has corrosion resistance. And durability can be improved over a long period of time.

  Here, in the present embodiment, the protective cover 18 and the outer member 19 into which the fitting portion 18a of the protective cover 18 is press-fitted are integrally joined by welding. Specifically, end portions on the outer side of the fitting surface between the small-diameter portion 20 of the outer member 19 and the protective cover 18 are formed as a plurality of joint portions 17 in the circumferential direction by arc welding. Thereby, while being able to improve the airtightness of the fitting surface of the outer member 19 and the protective cover 18 over a long period of time, the positioning accuracy of the protective cover 18 can be improved.

  The protective cover 21 shown in FIG. 4 is formed into a cup shape by press working from a nonmagnetic austenitic stainless steel plate, and is fitted into a cylindrical fitting portion 10a that is press-fitted into the end inner peripheral surface 2d of the outer member 22. A disc-shaped shielding portion 10b extending radially inward from the fitting portion 10a, and a bottom portion 10d for closing the inner side end portion of the inner member 1 from the shielding portion 10b through the reduced diameter portion 18c. Yes.

  Here, the protective cover 21 is press-fitted into the end inner peripheral surface 2 d of the outer member 22, and the small diameter portion 20 is formed on the outer periphery of the end of the outer member 22. And the fitting part 10a of the protective cover 21 press-fitted into the outer member 22 is joined by welding. Specifically, end portions on the inner side of the fitting surface of the outer member 2 and the protective cover 21 are formed into a plurality of joint portions 17 in the circumferential direction by arc welding. Thereby, while being able to improve the airtightness of the fitting surface of the outer member 22 and the protective cover 21 over a long period of time, even if the small-diameter portion 23 of the outer member 22 is deformed due to the thermal effect in welding, It does not reach the pilot portion 23 which becomes a fitting surface with a knuckle (not shown).

  FIG. 5 is a modified example of the protective cover 21 described above. The protective cover 24 is basically different in shape from the protective cover 10 described above, and the same components are denoted by the same reference numerals and detailed description thereof is omitted.

  The protective cover 24 shown in FIG. 5 is formed in a cup shape by press working from a nonmagnetic austenitic stainless steel plate, and is fitted into a cylindrical fitting portion 24a that is press-fitted into the end inner peripheral surface 2d of the outer member 22. A disc-shaped shielding portion 10b extending radially inward from the fitting portion 24a, and a bottom portion 10d for closing the inner side end of the inner member 1 from the shielding portion 18b through the reduced diameter portion 18c. Yes.

  Here, the fitting portion 24a is reduced in width compared to the above-described one, and the inner side end of the fitting surface of the outer member 22 and the protective cover 24 is entirely welded by arc welding. It is set as the joining part 25 which turns. Thereby, since the airtightness of the fitting surface between the outer member 22 and the protective cover 24 can be further improved, it is not necessary to secure a fitting area, and at least the fitting is performed without increasing the press-fitting shimoshiro. As long as the accuracy can be maintained, the width of the fitting portion 24a can be reduced as much as possible, and the bearing portion can be made compact.

  A protective cover 26 shown in FIG. 6 is a modification of the above-described protective cover 24 (see FIG. 5), and is formed into a cup shape by pressing from a nonmagnetic austenitic stainless steel plate. The disk-shaped shielding part 26a fitted to 27a and the bottom part 10d which closes the inner side end of the inner member 1 from the shielding part 26a through the reduced diameter part 18c are provided.

  Here, the outer member 27 and the protective cover 26 are integrally joined by laser welding. That is, the fitting portion between the stepped portion 27a of the outer member 27 and the shielding portion 26a of the protective cover 26 is a joint portion 28 that extends over the entire circumference. This laser welding is performed by irradiating the joint portion 28 with a laser beam having a high energy density collected by a condensing unit, causing the temperature of the joint portion 28 to rapidly increase to cause local melting / solidification. Therefore, not only high-speed welding is possible, but also deep penetration welding is possible, and there is little thermal influence, and the deformation associated therewith is small, so that reliability can be improved. In addition to this laser welding, for example, plasma welding, electron beam welding, high-speed pulse projection welding, and the like can be exemplified.

  In addition to such welding, the outer member 27 and the protective cover 26 may be integrally joined by brazing. This brazing uses a base material to be joined, that is, an alloy having a melting point lower than that of the outer member 27 and the protective cover 26 and joins the base material by a peeling phenomenon without melting, so that thermal deformation is reliably suppressed. The desired accuracy can be ensured.

  A protective cover 29 shown in FIG. 7 is a modification of the above-described protective cover 26 (see FIG. 6). In the present embodiment, the annular protrusion 31 is formed on the inner side end face of the outer member 30. The protective cover 29 is formed into a cup shape by press working from a nonmagnetic austenitic stainless steel plate, and has a cylindrical fitting portion 29a that is press-fitted into the annular protrusion 31 of the outer member 30, and the fitting portion 29a. A disc-shaped shielding portion 10b extending radially inward from the bottom portion 10b, and a bottom portion 10d for closing the inner side end portion of the inner member 1 from the shielding portion 10b through the reduced diameter portion 18c.

  The outer member 30 and the protective cover 29 are integrally joined by TIG welding. That is, the fitting portion between the annular protrusion 31 of the outer member 30 and the fitting portion 29a of the protective cover 29 is a joint portion 32 that extends over the entire circumference. Usually, when two members are welded, the molten state differs depending on the volume of the welded portion. That is, in the present embodiment, the plate thickness of the protective cover 29 is thinner than the end portion of the outer member 30, and heat is likely to enter the protective cover 29 more than the outer member 30. By providing an annular protrusion 31 at the portion and fitting and welding the protective cover 29 to the annular protrusion 31, the molten state of both can be made equal.

  This TIG welding is a method of welding with a tungsten electrode that is resistant to heat and flowing an inert gas such as argon gas around it. Since there is no oxygen (air) in the welded part and the material is not oxidized, stainless steel or aluminum Suitable for welding alloys. In addition, since the electrode has a high melting point tungsten, the electrode does not decrease over a long period of time, the productivity is improved, and sparks are not scattered, so that adverse effects on the surrounding environment can be prevented.

  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 the wheel bearing device on the driven wheel side of the first to third generation structure of the inner ring rotation type.

DESCRIPTION OF SYMBOLS 1 Inner member 2, 19, 22, 27, 30 Outer member 2a Outer rolling surface 2b Car body mounting flange 2c End side 2d of inner side of outer member End inner peripheral surface 3 of outer member 3 Rolling element 4 Hub ring 4a 5a Inner rolling surface 4b Small diameter step portion 5 Inner ring 5b Large end surface 6 Wheel mounting flange 6a Hub bolt 6b Inner side base 7 Clamping portion 8 Cage 9 Outer side seals 10, 18, 21, 24, 26, 29 Protection Cover 10a, 18a, 24a, 29a Fitting part 10b, 18b, 26a Shield part 10c Cylindrical part 10d Bottom part 11 Core metal 12 Seal member 12a, 12b Side lip 12c Grease lip 13 Support ring 13b Standing plate part 14 Magnetic encoder 15 Rotational speed Sensor 16 Detection part 17, 25, 28, 32 Joint part 18c Reduced diameter part 20 Small diameter part 23 Pilot part 27a Stepped part 31 Annular protrusion 50 Outer member 50a Outer rolling surface 50b Car body mounting flange 51 Inner member 52 Ball 53 Hub wheel 54a Inner rolling surface 53b Small diameter step portion 53c Clamping portion 54 Inner ring 55 Encoder 56 Support ring 57 Encoder body 58 Cover 59 Cylindrical portion 60 flat plate portion 61 minute gap 62 non-contact portion D1 inner diameter D2 of inner end portion of outer member outer diameter L1 of non-contact portion α step difference between inner end surface of outer member and large end surface of inner ring Inclination angle

In order to achieve such an object, the invention according to claim 1 of the present invention has a vehicle body mounting flange integrally attached to the knuckle constituting the suspension device on the outer periphery, and double row outer rolling on the inner periphery. A hub wheel having an integrally formed outer member, a wheel mounting flange for mounting a wheel at one end, and a small-diameter step portion extending in the axial direction on the outer periphery, and the hub wheel An inner member comprising at least one inner ring press-fitted into a small-diameter step portion, and having an outer periphery formed with a double-row inner rolling surface opposite to the double-row outer rolling surface, the inner member and the outer member A plurality of rolling elements housed in a freely rolling manner between the rolling surfaces of the outer member, a seal is attached to an outer end of the outer member, and an inner member of the outer member A protective cover is attached to the end on the side, the outer member and the inner part In the wheel bearing device in which the opening of the annular space formed by the sealing member is sealed, the protective cover is fitted to the end portion of the outer member, and radially inward from the fitting portion. A disc-shaped shielding part, the rotation speed sensor approaching or abutting on the inner side surface, and a bottom part closing the inner side end of the inner member from the shielding part via a step part. In addition, the outer member and the protective cover are joined by welding, and the joint is sealed by the welding .

Claims (11)

An outer member integrally having a vehicle body mounting flange for being attached to a knuckle constituting a suspension device on the outer periphery, and an outer rolling surface of a double row integrally formed on the inner periphery;
From 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 in a freely rolling manner between the rolling surfaces of the inner member and the outer member;
An annular space is formed by the outer member and the inner member having a seal attached to the outer end portion of the outer member and a protective cover attached to the inner end portion of the outer member. In the wheel bearing device in which the opening of
The protective cover has a fitting portion attached to an end portion of the outer member, and a disk that extends radially inward from the fitting portion, and the rotational speed sensor is close to or abuts on the inner side surface. And a bottom portion that covers the inner side end of the inner member from the shielding portion via a step portion, and the outer member and the protective cover are joined by welding, A bearing device for a wheel, wherein a joint portion is sealed by the welding.   The wheel bearing device according to claim 1, wherein the protective cover is formed from a steel plate by pressing.   The wheel bearing device according to claim 1 or 2, wherein a magnetic encoder is fitted on the inner ring, and the protective cover is formed of a nonmagnetic austenitic stainless steel plate.   4. The wheel bearing device according to claim 3, wherein the detection surface of the magnetic encoder and the large end surface of the inner ring are substantially flush with each other, or are set so as to slightly protrude toward the inner side from the large end surface.   A fitting portion of the protective cover is formed in a cylindrical shape and is press-fitted into the inner peripheral surface of the end portion of the outer member, and a pilot portion serving as a fitting surface with the knuckle is provided on the outer periphery of the end portion of the outer member. The wheel bearing device according to claim 1, wherein the wheel bearing device is formed and has a small-diameter portion formed closer to the end face than the pilot portion.   The wheel bearing device according to any one of claims 1 to 3, wherein a joint portion between the outer member and the protective cover is formed over the entire circumference.   The wheel bearing device according to any one of claims 1 to 3, wherein an annular protrusion is formed at an end portion of the outer member, and a fitting portion of the protective cover is attached to the annular protrusion and welded.   The wheel bearing device according to claim 1, wherein the welding is laser welding.   The wheel bearing device according to claim 1, wherein the welding is brazing.   The wheel bearing device according to claim 1, wherein the welding is TIG welding.   The wheel bearing device according to any one of claims 1 and 7 to 10, wherein a surface of the joint portion by welding is coated or rust-proofed.

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