JP2014020404A - Wheel bearing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wheel bearing device improved in reliability by improving accuracy in fastening processing and concentricity of a hub ring and a gear member.SOLUTION: In the wheel bearing device of a second or third generation structure in which a gear member 24 for selective switching of four-wheel driving/two-wheel driving, is fixed to an internal member including a hub ring 4, and inner rings 5, 7 fitted to the hub ring 4, the hardened ring-shaped gear member 24 is mounted on an end portion of a small-diameter step portion of the hub ring 4, the gear member 24 is provided with a gear portion 24a on its outer periphery, and a spline portion 24b engaged with a hub spline 25 formed on an outer peripheral face of the small diameter step portion, on its inner periphery, the hub spline 25 has a twist angle inclined at a prescribed angle to an axis, and preload is applied between the hub spline 25 and the spline portion 24b of the gear member 24.

Description

  The present invention relates to a wheel bearing device for rotatably supporting a wheel of an automobile or the like, and more particularly to a wheel bearing device having a clutch function for switching a wheel between driving and non-driving.

  In some four-wheel drive vehicles, a front wheel or a rear wheel can be selectively switched to a driven wheel by a clutch function provided in a wheel bearing device. As shown in FIG. 7, such a wheel bearing device 50 with a clutch function is externally fitted to a hub shaft 52 coaxially mounted on a drive shaft 51 and an axial center of the hub shaft 52. A double-row tapered roller bearing 53 as a rolling bearing, and a coupler ring 54 arranged in parallel with the double-row tapered roller bearing 53 in the axial direction. The wheel bearing device 50 is coaxially supported on the axle 51 by a deep groove ball bearing 55 and a needle roller bearing 56 disposed between the axle 51 and the hub shaft 52. G is a gear ring that can slide in the axial direction.

  The hub shaft 52 includes a sleeve portion 57 formed coaxially with the axle 51, a flange portion 58 formed on one end side (wheel side) of the sleeve portion 57 and extending radially outward, and a sleeve And a bent portion 59 formed on the other end side (the vehicle body center side) of the portion 57 and bent outward in the radial direction. Further, a spline portion 60 in which a plurality of spline grooves (spline grooves) 60 a and a plurality of spline protrusions 60 b are alternately formed is formed on the outer peripheral surface of the sleeve portion 57 in the vicinity of the bent portion 59. The spline portion 60 is formed on the inner peripheral surface of the coupler ring 54, and meshes with an inner peripheral spline portion 61 in which a plurality of spline grooves (spline grooves) 61a and a plurality of spline protrusions 61b are alternately formed. It is configured as follows. Further, a through hole (fastening hole) 58a is formed in the flange portion 58, and a wheel of a wheel as a rotating body (see FIG. 5) is obtained by passing a fastening member BO such as a bolt through the through hole (fastening hole) 58a. (Not shown).

The double-row tapered roller bearing 53 includes an inner ring 62, an outer ring 63, and tapered rollers 64 and 65 as rolling elements that are interposed between the inner and outer rings 62 and 63 and are arranged in two rows in the axial direction. Yes.
Specifically, the inner ring 62 is divided into a first inner ring member 66 having a first track portion 66a and a second inner ring member 67 having a second track portion 67a. The first inner ring member 66 and the second inner ring member 67 are in contact with each other, and the end surface 66b on the first inner ring member 66 side is in contact with the root portion of the flange portion 58 of the hub shaft 52. The end surface 67 b on the inner ring member 67 side of 2 is in contact with the end surface of the coupler ring 54. Therefore, the inner ring 62 (the first inner ring member 66 and the first inner ring member 66 and the double ring tapered roller bearing 53) is formed between the root portion of the flange portion 58 of the hub shaft 52 and the bent portion 59 of the hub shaft 52. The second inner ring member 67) is fixed and is configured so as not to rotate with respect to the hub shaft 52.

  On the other hand, the outer ring 63 includes a first raceway portion 63a and a second raceway portion 63b, and a flange portion 63c extending outward in the radial direction. The flange portion 63c is attached and fixed to a steering knuckle (suspension device) or the like of the vehicle body. Reference numeral 68 denotes a seal member.

  The coupler ring 54 is annular as a whole, and is arranged side by side in the axial direction so as to contact the other end side surface (end surface 67b on the second inner ring member 67 side) of the double row tapered roller bearing 53. An outer peripheral side spline portion 69 in which a plurality of spline grooves (spline grooves) 69a and a plurality of spline protrusions 69b are alternately formed is formed on the outer peripheral surface of 54. The outer peripheral side spline portion 69 is configured to mesh with the spline portion G1 of the gear ring G.

  Referring also to FIG. 8, the inner peripheral edge of the spline protrusion 61b on the other end side in the axial direction of the inner peripheral side spline 61 of the coupler ring 54 is chamfered into a curved surface so that the other end is chamfered. Part 70. The other end side chamfer 70 is formed so that the entirety thereof is positioned on the outer side in the axial direction than the spline part 60 of the hub shaft 52. Specifically, the distance from the side surface 71 on the other end side in the axial direction of the coupler ring 54 to the one end portion (on the spline portion 60 side of the hub shaft 52) 71a of the other end side chamfer 70 is L, and the axial direction of the coupler ring 54 When the distance from the side surface 71 on the other end side to the end point portion 60c of the spline groove (spline groove) 60a of the spline portion 60 of the hub shaft 52 is X, the distance L is formed to be smaller than the distance X. Yes. As a result, when the other axial end of the hub shaft 52 is bent and pressed, the bending radius of the bent portion can be increased, so that a crack (caulking crack) occurs in the root portion of the bent portion 59. Can be effectively suppressed (see, for example, Patent Document 1).

Japanese Patent No. 4466302

  In this conventional wheel bearing device 50, when the other axial end portion of the hub shaft 52 is bent and pressed, the bending radius of the bent portion can be increased, so that the root portion of the bent portion 59 is cracked. It is possible to effectively suppress the occurrence, but the inner peripheral side spline part 61 of the coupler ring 54 is engaged with the spline part 60 of the hub shaft 52, and the other axial end part of the hub shaft 52 is bent to couple the ring. When caulking and fixing 54, the caulking jig (not shown) is caulked while swinging, so that the coupler ring 54 may swing around. As a result, there is a possibility that the caulking accuracy may be lowered, or a misalignment may occur between the coupler ring 54 and the hub shaft 52.

  The present invention has been made in view of such circumstances, and provides a wheel bearing device that improves the accuracy of caulking and improves the concentricity of the hub wheel and the gear member to improve reliability. The purpose is to do.

  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 outer member integrally formed with a surface, a wheel mounting flange for mounting a wheel at one end, and a cylindrical small-diameter step portion extending in the axial direction on the outer periphery; and An inner member having at least one inner ring press-fitted into a small-diameter step portion of the hub wheel through a predetermined shimoshiro and having a double-row inner rolling surface facing the double-row outer rolling surface on the outer periphery. And a double row rolling element that is rotatably accommodated between the rolling surfaces of the inner member and the outer member via a cage, wherein the hub wheel has a small diameter. A ring-shaped gear member that has been cured is attached to the end of the step, The gear member has a gear portion formed on the outer periphery, a spline portion that meshes with a hub spline formed on the outer peripheral surface of the small-diameter stepped portion on the inner periphery, and the hub spline and the spline portion of the gear member. A preload is applied between them.

  As described above, the second or third generation structure in which the gear member that selectively switches between the four wheels and the two wheels is fixed to the inner member having the hub wheel and the inner ring fitted to the hub wheel. In the wheel bearing device, a ring-shaped gear member that is hardened is attached to an end portion of the small-diameter step portion of the hub wheel. The gear member has a gear portion formed on the outer periphery and a small-diameter step portion on the inner periphery. A spline portion that meshes with the hub spline formed on the outer peripheral surface is formed, and since a preload is applied between the hub spline and the spline portion of the gear member, the play in the circumferential direction of the fitting portion is killed, It is possible to improve the accuracy of the caulking process, and to provide a wheel bearing device with improved reliability by improving the coaxiality of the hub wheel and the gear member.

  Preferably, if the hub spline is provided with a torsion angle inclined at a predetermined angle with respect to the axis as in the invention described in claim 2, the initial insertion of the gear member can be used as a clearance. Phase alignment can be easily performed and assembly workability can be improved.

  If the predetermined hardened layer is formed by induction hardening over the entire area of the hub spline as in the invention described in claim 3, the wear of the hub spline can be suppressed and the allowable torque can be suppressed. Becomes higher and durability can be improved. In addition, the accuracy of the caulking process can be further improved, and the strength of the final product can be guaranteed.

  Further, as in the invention described in claim 4, if a predetermined hardened layer is formed by induction hardening over the vicinity of the hub spline or a part of the hub spline, it is easy to preload the fitting portion. The assembly workability can be improved.

  Further, as in the invention described in claim 5, the gear member is formed of a steel material made of carbon 0.15 to 0.45 wt%, and is hardened to the core by quenching, and its surface hardness is set. If it is set to 40 HRC or more, a gear part having an appropriate hardness can be obtained, and desired strength can be ensured as well as the gear part and the spline part.

  Further, as in the invention described in claim 6, the gear member is formed of chromium molybdenum steel containing 0.15 to 0.3 wt% of Mo, and a predetermined hardened layer is formed on the surface by carburizing and quenching. If the hardness is set to 40 HRC or more, brittleness can be suppressed, and the occurrence of micro cracks during caulking is surely prevented, and the strength when driving force is applied is ensured. Can do.

  Further, as in the invention according to claim 7, the end surface of the spline protrusion of the hub spline is formed by a single arc having a predetermined radius of curvature R, and this radius of curvature R is the inner side of the gear member. If it is set to be larger than the dimension A from the end face of the spline to the edge of the spline ridge (R> A) and larger than the height h of the spline ridge (R> h), The root part of the crimped part after tightening has a large rounded shape, which can prevent the stress-concentrated V-shape and prevent cracking of the crimped part and gear member during the crimping process. And the occurrence of cracks during use can be effectively suppressed.

  In addition, as in the invention described in claim 8, the surface roughness of the contact surface of the gear member with the inner ring is set to Ra 1.6 or less, and the contact width with the caulking portion is 1 mm or more. If set, the inner ring and the gear member are brought into close contact with each other, and the frictional resistance of the contact surface is surely increased, and the inner ring can be pushed in to secure a desired axial force. When an external force is applied, the axial force is reduced. It is possible to prevent the bearing preload from being lost due to zero.

  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 cylindrical small-diameter step portion extending in the axial direction on the outer periphery, and a small-diameter step portion of the hub wheel having a predetermined diameter An inner member comprising at least one inner ring that is press-fitted through a nip and having a double-row inner rolling surface facing the double-row outer rolling surface on the outer periphery; and the inner member and the outer member In a wheel bearing device including a double row rolling element that is rotatably accommodated between both rolling surfaces of a side member via a cage, the end portion of the small-diameter step portion of the hub wheel is cured. A ring-shaped gear member is mounted, and this gear member has a gear on the outer periphery. And a spline portion that meshes with a hub spline formed on the outer peripheral surface of the small-diameter step portion is formed on the inner periphery, and a preload is applied between the hub spline and the spline portion of the gear member. As a result, it is possible to eliminate the backlash in the circumferential direction of the fitting part, improve the accuracy of the caulking process, and provide a wheel bearing device with improved reliability by improving the coaxiality of the hub wheel and the gear member. can do.

It is a longitudinal section showing one embodiment of a wheel bearing device concerning the present invention. (A) is a principal part enlarged view which shows the bearing part of FIG. 1, (b) is a principal part enlarged view which shows the seal | sticker of FIG. It is a principal part enlarged view which shows the hub spline part of the hub ring which concerns on this invention. It is IV arrow line view of FIG. It is a principal part enlarged view which shows the hardened layer pattern of the hub ring 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. It is a principal part enlarged view of FIG.

  An outer member integrally having a vehicle body mounting flange to be attached to a knuckle constituting a suspension device on the outer periphery, a double row tapered outer rolling surface formed integrally on the inner periphery, and a wheel on one end A hub wheel integrally having a wheel mounting flange for mounting a wheel and having a cylindrical small-diameter step portion extending in an axial direction from the wheel mounting flange via a shoulder portion on the outer periphery, and a small-diameter step portion of the hub wheel An inner member consisting of a pair of inner rings that are press-fitted through a predetermined squeeze and have a tapered inner rolling surface facing the outer rolling surface of the double row on the outer periphery, and the inner member and the A double row tapered roller that is rotatably accommodated via a cage between both rolling surfaces of the outer member, and plastically deforms the end portion of the small diameter step portion of the hub wheel radially outward. A wheel shaft in which the inner ring is fixed in the axial direction by a caulking portion formed by In the apparatus, a hardened ring-shaped gear member is attached to the end of the small-diameter step portion of the hub wheel, the gear member has a gear portion formed on the outer periphery, and an outer peripheral surface of the small-diameter step portion on the inner periphery. A spline portion that meshes with the hub spline formed on the shaft is formed, and a torsion angle that is inclined by a predetermined angle with respect to the axis is provided on the hub spline, and between the hub spline and the spline portion of the gear member. Preload is applied.

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 an enlarged view of a main part showing a bearing part of FIG. 1, and (b) is a seal of FIG. FIG. 3 is an enlarged view of a main part showing a hub spline part of the hub wheel according to the present invention, FIG. 4 is a view taken along arrow IV of FIG. 3, and FIG. The principal part enlarged view which shows a hardened layer pattern, FIG. 6 is a principal part enlarged view which shows the 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 used on the drive wheel side, and the inner member 1, the outer member 2, and the double row rolling elements (conical rollers) 3, 3 accommodated between the members 1 and 2 so as to roll freely. And. The inner member 1 includes a hub ring 4 and a pair of inner rings 5 and 7 plastically coupled to the hub ring 4.

  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 a cylindrical shape that extends in the axial direction from the wheel mounting flange 6 to the outer periphery via a shoulder portion 4a. The small diameter step 4b is formed. Further, hub bolts 6 a for fixing the wheels at the circumferentially equidistant positions of the wheel mounting flange 6 are planted.

  Each of the pair of inner rings 5 and 7 has a tapered inner rolling surface 5a formed on the outer periphery, and is press-fitted into the small-diameter step portion 4b of the hub wheel 4 via a predetermined squeeze. As shown in an enlarged view in FIG. 2 (a), large collar portions 5b and 5b for guiding the rolling elements 3 are formed on the large diameter side of the inner rolling surface 5a, and on the small diameter side. A back-to-back type set in a state where the small flange portions 5c and 5c for preventing the rolling element 3 from falling off are formed and the small end surfaces 5d and 5d (front end surfaces) of the inner rings 5 and 7 are butted together. A double row tapered roller bearing is configured. The pair of inner rings 5 and 7 have the same specifications, but the chamfered portion of the end portion on the large diameter side of the inner ring 5 on the outer side of the pair of inner rings 5 and 7 is larger than the inner ring 7 on the inner side. The only difference is that it is formed.

  As shown in FIG. 1, the outer member 2 is integrally formed with a vehicle body mounting flange 2b to be attached to a knuckle (not shown) on the outer periphery, and is formed in a tapered double row that opens outward on the inner periphery. The outer rolling surfaces 2a and 2a are integrally formed. And the double row rolling elements 3 and 3 are accommodated so that rolling is possible via the holder | retainer 8 and 8 between both rolling surfaces. Further, an annular groove 9 is formed on the outer diameter surface fitted inside the knuckle, and an elastic ring 10 such as an O-ring is attached to the annular groove 9, thereby improving the airtightness of the fitting portion with the knuckle. be able to.

  The hub wheel 4 is formed of medium-high carbon steel (carbon steel for SC system mechanical structure of JIS standard) containing 0.40 to 0.80 wt% of carbon such as S53C, and has a high frequency extending from the shoulder 4a to the small diameter step 4b. A predetermined hardened layer is formed in the range of surface hardness of 58 to 64 HRC by quenching. Further, the inner rings 5 and 7 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 part by quenching. A caulking portion 4c described later is an unquenched portion with the surface hardness after forging. This facilitates caulking and prevents the occurrence of microcracks during processing, and has sufficient mechanical strength against the rotational bending load applied to the wheel mounting flange 6, and the durability of the hub wheel 4. Improves.

  The outer member 2 is formed of medium and high carbon steel containing carbon of 0.40 to 0.80 wt% such as S53C, as in the case of the hub wheel 4, and at least the double-row outer raceway surfaces 2a and 2a are formed on the surface by induction hardening. A predetermined curing process is performed in the range of 58 to 64 HRC. Seals 11, 11 are attached to the opening of the annular space formed between the outer member 2 and the inner rings 5, 7, leakage of the lubricating grease sealed inside the bearing, rainwater, dust, etc. from the outside Is prevented from entering the inside of the bearing.

  As shown in an enlarged view in FIG. 2B, the seal 11 is configured by a so-called pack seal including a slinger 12 and an annular seal plate 13 that are arranged to face each other. Slinger 12 is an austenitic stainless steel plate (JIS standard SUS304, etc.), a ferritic stainless steel plate (JIS standard SUS430, etc.), or a rust-proof cold rolled steel plate (JIS standard SPCC, etc.). From a cylindrical portion 12a having a substantially L-shaped cross section by press working and press-fitted into the large collar portion 5b of the inner rings 5, 7, and a standing plate portion 12b extending radially outward from the cylindrical portion 12a. Become.

  On the other hand, the seal plate 13 includes a cored bar 14 fitted into the end of the outer member 2 and a seal member 15 integrally joined to the cored bar 14 by vulcanization adhesion. The cored bar 14 is formed in a substantially L-shaped cross section by pressing from an austenitic stainless steel plate or a cold-rolled steel plate that has been rust-proofed.

  The seal member 15 is made of synthetic rubber such as NBR (acrylonitrile-butadiene rubber), and integrally includes a pair of side lips 15a and 15b extending obliquely outward in the radial direction and a grease lip 15c extending inclined inward of the bearing. Have. The side lips 15a and 15b are in sliding contact with the side surface of the standing plate portion 12b of the slinger 12 via a predetermined axial shimiro, and the grease lip 15c is slid onto the cylindrical portion 12a of the slinger 12 via a predetermined radial shimillo. It touches. In addition to the exemplified NBR, the seal member 15 is made of, for example, HNBR (hydrogenated acrylonitrile butadiene rubber), EPDM (ethylene propylene rubber), etc., which have 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 the present embodiment, as shown in FIG. 2A, a sensor insertion hole 16 is formed between the outer rolling surfaces 2a and 2a of the double row of the outer member 2 so as to penetrate in the radial direction. A rotation speed sensor 17 is inserted into the hole 16. This rotational speed sensor 17 incorporates a magnetic detecting element such as a Hall element, a magnetoresistive element (MR element), etc. that changes its characteristics according to the direction of flow of magnetic flux, and a waveform shaping circuit that adjusts the output waveform of this magnetic detecting element. The synthetic resin is integrally molded by injection molding. And it has the shaft-shaped insertion part 17a inserted in the sensor insertion hole 16, and the non-insertion part 17b located in the exterior of the outer member 2. As shown in FIG. An annular groove 18 is formed on the outer periphery of the insertion portion 17a, and an elastic ring 19 made of an O-ring or the like is attached to the annular groove 18. Moreover, the non-insertion part 17b is formed in the shape seated on the sensor attachment part 20 of the outer member 2, and is fastened via the attachment piece (not shown) extended to a side.

  On the other hand, a pulsar ring 21 facing the rotational speed sensor 17 via a predetermined radial clearance (air gap) is externally fitted and fixed to the outer periphery of the outer ring inner ring 5 on the small collar part 5c side. The pulsar ring 21 is formed in the shape of a spur gear composed of an uneven portion 21a. Accordingly, the direction of the magnetic field alternately changes on the circumference along with the rotation of the hub wheel 4, and the rotation speed sensor 17 can detect the rotation speed of the wheel.

  The integration of the hub wheel 4 and the inner rings 5 and 7 is achieved by pressing the inner rings 5 and 7 into the small-diameter step portion 4b of the hub wheel 4 via a predetermined shimiro, and the end of the small-diameter step portion 4b in the radial direction. This is performed by a caulking portion 4c formed by plastic deformation outward (see FIG. 1).

  In the present embodiment, the wheel bearing device in which the rolling element 3 is constituted by a double row tapered roller bearing made of a tapered roller is illustrated. However, the wheel bearing device according to the present invention is not limited to this, for example, illustrated However, the rolling element 3 may be composed of a double-row angular ball bearing using balls.

  Further, as shown in FIG. 1, a shaft portion of an outer joint member constituting a constant velocity universal joint (not shown) is rotatably supported on the inner circumference of the hub wheel 4 via rolling bearings 22 and 23. Out of these rolling bearings 22 and 23, the outer side rolling bearing 22 is a deep groove ball bearing, and the inner side rolling bearing 23 is a shell needle roller bearing.

  Here, as shown in FIG. 2A, the inner ring 7 is fixed to the hub wheel 4 in the axial direction by a caulking portion 4 c via a ring-shaped gear member 24. The gear member 24 has a gear portion 24a formed on the outer periphery and a spline portion 24b formed on the inner periphery. The inner peripheral spline portion 24 b meshes with a hub spline 25 formed on the outer peripheral surface on the inner side of the small-diameter step portion 4 b of the hub wheel 4.

  The gear member 24 is pressed toward the inner ring 7 on the inner side by the crimping pressure from the crimping portion 4c that comes into contact with the end face on the inner side, and is fixed in close contact with the large end surface 7a of the inner ring 7. Yes. The caulking pressure acting from the caulking portion 4c ensures that the gear member 24 and the pair of inner ring members 5 and 7 are fixed to the hub wheel 4.

  Further, the gear portion 24 a of the gear member 24 meshes with the ring-shaped slide gear 28. The slide gear 28 selectively meshes with the gear portion 27 of the outer joint member 26 by sliding in the axial direction. In other words, the driving force is transmitted from the constant velocity universal joint to the wheel via the gear member 24 and the hub wheel 4 in a state where the gear member 24 and the gear portion 27 of the outer joint member are connected via the slide gear 28. The At this time, the wheel supported by the hub wheel 4 becomes a driving wheel. In the state where the slide gear 28 is not engaged with the gear member 24, the driving force is not transmitted to the wheel, and at this time, the wheel supported by the hub wheel 4 becomes a driven wheel, and switching between four wheels and two wheels is selective. To be done.

  In the present embodiment, the gear member 24 is formed of a steel material having a carbon content of medium carbon steel or less, such as chromium steel. Specifically, it is formed from a steel material containing 0.15 to 0.45 wt% carbon, preferably 0.38 to 0.43 wt% carbon. And hardening processing is carried out in the range of 40-55 HRC (392-600 HV) to the core part by sublimation quenching (quenching tempering). As a result, when the caulking portion 4c of the hub wheel 4 is caulked, an axial force can be applied via the gear member 24, and a desired axial force can be ensured. Further, wear of the spline portion 24b on the inner periphery of the gear member 24 can be suppressed, and the allowable torque can be increased to improve the strength and durability.

  Thus, with respect to the hub wheel 4 made of medium and high carbon steel such as S53C, the amount of Cr in the gear member 24 increases to approximately 0.09 to 0.12 wt%, and the tenacity increases. In addition, when the carbon amount is high-carbon steel, the hardness becomes about HRC60 (700HV). However, in the present invention, the carbon content is hardened by sub-firing from a steel material having a medium carbon steel or less. A gear portion having an appropriate hardness can be obtained. That is, a hardness difference of about 132 to 340 HV can be made with respect to the surface hardness 260 HV of the crimped portion 4 c, and desired strength can be ensured as well as the gear portion 24 a and the spline portion 24 b. Therefore, in the caulking step, it is possible to prevent excessive stress from being generated in the gear member 24 and to cause deformation and micro cracks, and when the caulking portion 4c is formed, the small diameter step portion 4b of the hub wheel 4 is formed. Can be plastically deformed outward in the radial direction, preventing a caulking failure such as a microcrack in the caulking portion 4c, and a bearing preload set initially for a long period of time. Can be maintained.

  Note that the gear member 24 may be made of chromium molybdenum steel such as SCM440 or SCM430 to which Mo (molybdenum) is added at approximately 0.15 to 0.3 wt%. Then, if a predetermined hardened layer is formed on the surface by carburizing and quenching and the surface hardness is set in the range of 40 to 55 HRC, the brittleness can be suppressed and the generation of microcracks during the caulking process is ensured. Therefore, it is possible to ensure the strength when the driving force is applied.

  Further, in the present embodiment, the surface roughness of the large end surface 7a of the inner ring 7 is set to Ra 0.63 or less by grinding after the heat treatment, and the outer surface of the gear member 24 that comes into contact with the large end surface 7a of the inner ring 7 is set. The side surface 24c is ground to have a surface roughness of Ra 1.6 or less, preferably Ra 0.63 or less. As a result, the inner ring 7 and the gear member 24 are brought into close contact with each other, the frictional resistance of the contact surface is increased, the torque applied to the hub spline 25 is reduced, and the wheel bearing device is provided with improved durability. be able to. Note that Ra is one of JIS roughness shape parameters (JIS B0601-1994), and is an arithmetic average roughness, which means an average value of absolute value deviations from an average line.

  Furthermore, the contact width W between the gear member 24 and the caulking portion 4c is set to 1 mm or more. Thereby, the inner ring 7 can be pushed in via the gear member 24 by the caulking portion 4c, and a desired axial force can be secured. In other words, it is usually necessary that the axial force becomes zero when the external force is applied to the maximum axial force 20 kN input when the vehicle travels, and the bearing preload does not escape. Here, as a result of measuring the axial force by changing the pushing amount in the caulking process test conducted by the present applicant, in order to secure the lower limit 20 kN of the axial force, the gear member 24 and the caulking portion 4c are secured. It has been found that a contact width W of at least 1 mm is required.

  Here, as shown in an enlarged view in FIG. 3, a hub spline 25 is formed on the outer periphery of the small-diameter step portion 4b of the hub wheel 4 by hobbing. The end surface of the spline protrusion 25a of the hub spline 25, that is, the range of the edge B of the spline protrusion 25a of the hub spline 25 and the bottom C of the spline protrusion 25b is a single circular arc having a predetermined radius of curvature R. It is formed with. The radius of curvature R is larger than the dimension A from the inner end face 24d of the gear member 24 to the edge B of the spline protrusion 25a (R> A), and larger than the height h of the spline protrusion 25a. (R> h). As a result, it is possible to prevent the root portion of the caulking portion 4c after caulking from being formed into a shape having a large roundness and a V-shape in which stress is easily concentrated. Therefore, it is possible to provide a wheel bearing device that effectively suppresses the occurrence of caulking cracks and cracks during use in the caulking portion 4c and the gear member 24 during caulking, and improves durability. . The hub spline 25 may be formed by vibration press or rolling other than hobbing.

  Further, as shown in FIG. 4, the hub spline 25 is provided with a torsion angle α inclined by a predetermined angle with respect to the axis, and the spline protrusion 25a before caulking and the spline portion 24b of the gear member 24 are connected to each other. Preload is applied so that there is a shimoshiro in the fitting. As a result, the initial insertion of the gear member 24 can be used as a clearance, spline phasing can be easily performed, assembling workability can be improved, and play in the circumferential direction of the fitting portion can be killed to improve the accuracy of the caulking process. Thus, it is possible to provide a wheel bearing device with improved reliability by improving the coaxiality of the hub wheel 4 and the gear member 24.

  Here, the twist angle α is set to 5 ° or less, preferably 1 to 3 °. Further, the term “smoke” as used herein refers to the spline of the hub spline 25 based on the distance between the teeth of the spline portion 24b of the gear member 24 in the contact length L1 between the hub spline 25 of the hub wheel 4 and the spline portion 24b of the gear member 24. When the tooth thickness of the ridge 25a (tooth thickness when the contact length is projected with the twist angle α) is subtracted, it is a negative state. In this way, the hub spline 25 is twisted, and the tooth surface texture before crimping is in a state of squeezing. The tooth surface squeezing is set as a clearance at the initial stage of spline insertion, and there is a squeezing in the middle of insertion (press-fit state). Make a hameai like that. Thereby, since the hub wheel 4 and the gear member 24 are fixed by tooth contact before caulking, the gear member 24 does not swing around during caulking and stable caulking is possible. Further, since the gear member 24 does not swing, the coaxiality between the gear member 24 and the hub wheel 4 is improved.

  Here, the hub spline 25 is provided with a torsion angle α and preload is applied between the hub spline 25 and the spline portion 24b of the gear member 24. However, the present invention is not limited to this. The tooth thickness of 25a and the tooth thickness of the spline part 24b of the gear member 24 may be formed to be tight, and the gear member 24 may be press-fitted to apply a preload to the fitting part.

  FIG. 5 shows a hardened layer pattern of the hub wheel 4. The surface hardness is 50 to 64 HRC by induction hardening over the vicinity of the hub spline 25 from the shoulder 4 a to the small diameter step 4 b or a part thereof. A predetermined hardened layer 29 (indicated by cross hatching in the figure) is formed in the range. Thereby, a preload can be easily given to a fitting part and assembly workability | operativity can be improved.

  Further, as shown in FIG. 6, a predetermined hardened layer 30 having a surface hardness in the range of 50 to 64 HRC by induction hardening over the entire region of the hub spline 25 of the small diameter step 4b from the shoulder 4a of the hub wheel 4 '. (Indicated by cross hatching in the figure) may be formed. As a result, the wear of the hub spline 25 can be suppressed, the allowable torque can be increased, and the durability can be improved. In addition, the accuracy of the caulking process can be further improved, and the strength of the final product can be guaranteed.

  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.

  In the wheel bearing device according to the present invention, a gear member that selectively switches between four wheels and two wheels is fixed to an inner member having a hub wheel and an inner ring fitted to the hub wheel. It can be applied to a wheel bearing device of 2 or 3rd generation structure.

DESCRIPTION OF SYMBOLS 1 Inner member 2 Outer member 2a Outer rolling surface 2b Car body mounting flange 3 Rolling body 4, 4 'Hub wheel 4a Shoulder part 4b Small diameter step part 4c Clamping part 5, 7 Inner ring 5a Inner rolling surface 5b Large collar part 5c Small flange portion 5d Small end surface 6 Wheel mounting flange 6a Hub bolt 7a Large end surface 8 of inner ring Cage 9, 18 Annular groove 10, 19 Elastic member 11 Seal 12 Slinger 12a Cylindrical portion 12b Standing plate portion 13 Seal plate 14 Core metal 15 Seal Members 15a and 15b Side lip 15c Grease lip 16 Sensor insertion hole 17 Rotational speed sensor 17a Insertion portion 17b Non-insertion portion 20 Sensor mounting portion 21 Pulsar ring 21a Concavity and convexity portions 22 and 23 Rolling bearing 24 Gear member 24a Gear portion 24b Spline portion 24c Gear member Outer side surface 24d Gear member inner side surface 25 Hub spline 25a Hub spline Spline ridge 25b Hub spline spline ridge 26 Outer joint member 27 Outer joint member gear 28 Slide gear 29, 30 Hardened layer 50 Wheel bearing device 51 Axle 52 Hub shaft 53 Double row conical roller bearing 54 Coupler ring 55 Deep groove ball bearing 56 Needle roller bearing 57 Sleeve portion 58 Flange portion 58a Through hole 59 Folded portion 60 Spline portion 60a Hub shaft spline ridge 60b Hub shaft spline ridge 60c End point portion 61 of hub shaft spline ridge Inner peripheral side spline portion 61a Spline groove 61b Spline protrusion 62 Inner ring 63 Outer ring 63a First race portion 63b of outer ring Second race portion 63c of outer ring Flange portions 64, 65 Tapered rollers 66 First inner ring member 66a First track portion 66b End surface 67 of the first inner ring member Second inner ring member 67a Inner ring second raceway portion 67b Second inner ring member end face 68 Seal member 69 Outer peripheral side spline part 69a Coupler ring spline groove 69b Coupler ring spline protrusion 70 Other end side chamfer 71 Side surface 71a of the coupler ring One end portion A of the side surface of the other end A Dimension B from the end surface of the gear member to the end edge of the spline ridge C Edge of the spline ridge C of the hub spline Bottom G of the spline ridge Gear ring G1 Spline portion h Spline ridge height L Distance from the side of the coupler ring to one end of the other side chamfer L1 Contact length between the hub spline of the hub wheel and the spline of the gear member R Radius of curvature of the spline ridge W Gear Contact width X between the member and the caulking part or fixing nut X From the side of the coupler ring to the end of the spline groove on the hub shaft Distance to

Claims (8)

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;
A hub wheel integrally having a wheel mounting flange for mounting a wheel at one end and having a cylindrical small-diameter stepped portion extending in the axial direction on the outer periphery, and a small diameter stepped portion of the hub wheel via a predetermined squeezing An inner member formed of at least one inner ring press-fitted and formed with a double-row inner rolling surface facing the double-row outer rolling surface on the outer periphery;
In a wheel bearing device comprising a double-row rolling element that is accommodated so as to roll freely between both rolling surfaces of the inner member and the outer member via a cage,
A hardened ring-shaped gear member is attached to the end of the small-diameter step portion of the hub wheel. The gear member has a gear portion formed on the outer periphery and formed on the outer peripheral surface of the small-diameter step portion on the inner periphery. A wheel bearing device, wherein a spline portion meshing with the hub spline is formed, and a preload is applied between the hub spline and the spline portion of the gear member.   The wheel bearing device according to claim 1, wherein the hub spline is provided with a twist angle inclined by a predetermined angle with respect to an axis.   The wheel bearing device according to claim 1 or 2, wherein a predetermined hardened layer is formed by induction hardening over the entire area of the hub spline.   The wheel bearing device according to claim 1 or 2, wherein a predetermined hardened layer is formed by induction hardening over the vicinity of the hub spline or a part of the hub spline.   2. The gear member according to claim 1, wherein the gear member is formed of a steel material made of carbon of 0.15 to 0.45 wt%, and is hardened to the core portion by quenching and the surface hardness is set to 40 HRC or more. Wheel bearing device.   2. The gear member is formed of chromium molybdenum steel containing 0.15 to 0.3 wt% of Mo, a predetermined hardened layer is formed on the surface by carburizing and quenching, and the surface hardness is set to 40 HRC or more. The wheel bearing apparatus described in 1.   The end surface of the spline ridge of the hub spline is formed by a single arc having a predetermined radius of curvature R, and this radius of curvature R is a dimension A from the inner end surface of the gear member to the edge of the spline ridge. 2. The wheel bearing device according to claim 1, wherein the wheel bearing device is set to be larger (R> A) than the height h of the spline protrusions (R> h).   2. The wheel bearing according to claim 1, wherein a surface roughness of a contact surface of the gear member with the inner ring is set to Ra 1.6 or less, and a contact width with the caulking portion is set to 1 mm or more. apparatus.

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