JP2012180091A - Bearing device for wheel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a bearing device for a wheel, by which occurrence of brake judder is suppressed by improving face deflection accuracy of an end face of a flange, and in which environment friendly working can be performed and cost is reduced.SOLUTION: The bearing device for the wheel includes: a bearing 2 having rolling elements 30 of a plurality of rows disposed between opposing outer races 26 and 27, and inner races 28 and 29; and a hub wheel 1 mounted on the wheel. The inner race 28 of the outboard side is formed on the outer diameter surface of the hub wheel 1. The inner race 29 of the inboard side is formed in the inner wheel 24 fitted in the inboard side of the outer diameter surface of the hub wheel 1. The hub wheel 1 includes a wheel mounting flange 21 for mounting the wheel, and face working of the inner race 28 and the wheel mounting flange 21 in the hub wheel 1 is carried out on the same axis.

Description

  The present invention relates to a wheel bearing device for rotatably supporting a wheel with respect to a vehicle body in a vehicle such as an automobile.

  The wheel bearing device has evolved from a structure in which a double row rolling bearing called a first generation is used alone to a second generation in which a vehicle body mounting flange is integrated with an outer member. The third generation in which the inner raceway is integrally formed on one of the double row rolling bearings on the outer periphery of the hub wheel having an integral, and the constant velocity universal joint is integrated with the hub wheel. A fourth generation type has been developed in which the other inner rolling surface of the double row rolling bearing is integrally formed on the outer periphery of the outer joint member constituting the joint.

  As shown in FIG. 6, a wheel bearing device called a third generation (for example, Patent Document 1) is disposed on a hub wheel 102 having a flange 101 extending in the outer diameter direction and on the outer peripheral side of the hub wheel 102. The bearing structure 100 is provided.

  The hub wheel 102 has an outer raceway surface (inner race) 103 formed on the outer peripheral surface thereof, and hub bolts 105 for fixing the wheel are implanted at equal intervals in the circumferential direction of the flange 101. Further, an inner ring 107 of the bearing structure 100 is fitted to a small diameter step portion 106 formed on the inboard side of the hub wheel 102, and an inboard side raceway surface (inner race) 108 is formed on the outer peripheral surface of the inner ring 107. ing. The inner ring 107 is press-fitted with an appropriate tightening allowance to prevent creep, and is fixed to the hub ring 102 by caulking the end of the small-diameter stepped portion 106 of the hub ring 102 to the outside in the diametrical direction in order to prevent falling off.

  In this way, the raceway surface 103 located on the outboard side of the vehicle and the raceway surface 108 located on the inboard side form a double-row raceway surface. Here, the outboard side means a side that is outside the vehicle body with the wheel bearing device attached to the vehicle body, and the inboard side means a side that is inside the vehicle body.

  The outer ring 110 of the bearing structure 100 is formed with double-row raceway surfaces (outer races) 111 and 112 facing the raceway surfaces 103 and 108 of the hub wheel 102 and the inner ring 107 on the inner peripheral surface, and flanges (not shown) are attached to the vehicle body. Omitted). Double row rolling elements 109 are incorporated between the raceway surfaces 103 and 108 of the hub wheel 102 and the inner ring 107 and the double row raceway surfaces 111 and 112 of the outer ring 110.

  In this wheel bearing device, the raceway surfaces 111 and 112 of the outer ring 110 are hardened by induction hardening and tempering in order to improve rolling fatigue life and strength. That is, the outer ring 110 manufactured by forging from carbon steel for machine structure (S40C to S70C, etc.) is finished by turning so that the outer shape becomes the final shape, and then the outer ring 110 having the final finished shape is induction-hardened and tempered. Thus, the hardened layers 115 and 116 are formed on the raceway surfaces 111 and 112, respectively. The outer ring 110 is subjected to grinding finishing of the raceway surfaces 111 and 112 after induction hardening as described above.

  In addition, the region from the seal surface of the seal member S of the hub wheel 102 to the track surface 103 on the outboard side and the small-diameter step portion 106 is also hardened by induction hardening to form a hardened layer 117 in the region. By forming the hardened layer 117, the rolling fatigue life and strength of the wheel bearing device are improved. The hub wheel 102 is also subjected to grinding finishing of the raceway surface 103 and the like after induction hardening.

JP 2005-325903 A

In general, the braking force has increased due to the widespread use of disc brakes. On the other hand, when braking is performed with the disc brake rotor held between brake pads, vibration occurs especially when the vehicle is running at low speed, causing low frequency unpleasant noise. There are things to do. Such a phenomenon is called a brake judder, and in recent years, this analysis and improvement have attracted attention as a new technical issue as the performance and silence of vehicles become higher.

  The exact mechanism of the brake judder has not yet been elucidated in detail, but one factor is the accuracy of the pad sliding contact surface of the brake rotor. As for this runout accuracy, not only the runout accuracy of the brake rotor alone, but also the surface runout accuracy of the wheel mounting flange to which the brake rotor is mounted, the axial runout of the rolling bearing, the accuracy of the rolling surface, the assembly accuracy of the rolling bearing, etc. are accumulated. Ultimately, it appears as the surface runout accuracy on the side of the brake rotor.

  By the way, in the conventional wheel bearing device, the end surface on the outboard side of the flange of the hub wheel is a brake rotor mounting surface. For this reason, it is necessary to grind the end face. However, the grinding finish of the raceway surface 103 and the like and the grinding finish of the brake rotor mounting surface are performed in separate steps. Therefore, even if grinding of the brake rotor mounting surface is finished with high accuracy, when the brake rotor is assembled to the wheel bearing device, surface vibration of the end surface of the flange is likely to occur.

  Moreover, in grinding processing, it was necessary to use grinding coolant which is environmentally undesirable. Grinding has the drawbacks that the processing unit is small, the processing takes time and the efficiency is poor, the temperature rise is uneven, and deformation due to residual stress is difficult to predict.

  In view of the above problems, the present invention provides a wheel capable of suppressing the generation of brake judder by increasing the surface runout accuracy of the end face of the flange, enabling environmentally friendly processing, and reducing the cost. A bearing device is provided.

A first wheel bearing device of the present invention includes a bearing having a plurality of rows of rolling elements arranged between opposing outer races and an inner race, and a hub wheel attached to the wheel, and the outer diameter of the hub wheel. A bearing device for a wheel in which an inner race on the outboard side is formed on the surface, and an inner race on the inboard side is formed on an inner ring fitted on the inner board side of the outer diameter surface of the hub wheel, The wheel has a wheel mounting flange, and the inner race and the wheel mounting flange in the hub wheel are continuously subjected to surface machining on the same axis. This first wheel bearing device is a third generation wheel bearing device.

  A second wheel bearing device of the present invention includes a bearing having a plurality of rows of rolling elements arranged between opposing outer races and an inner race, and a hub wheel attached to the wheel, and the outer diameter of the hub wheel. A wheel bearing device in which an inner race on the outboard side is formed on the surface, and an inner race on the inboard side is formed on the outer diameter surface of the outer joint member of the constant velocity universal joint connected to the hub wheel. The hub wheel has a wheel mounting flange, and the inner race and the wheel mounting flange in the hub wheel are continuously subjected to surface machining on the same axis. This second wheel bearing device is a fourth generation wheel bearing device.

  According to the first and second wheel bearing devices of the present invention, the inner race and the wheel mounting flange in the hub wheel are subjected to surface machining on the same axis. Center misalignment between the center (rotation center) and the processing axis (rotation center) during processing of the wheel mounting flange can be avoided.

  The surface processing of the outer diameter surface of the hub wheel in the first and second wheel bearing devices is performed by forming a hardened portion on at least the seal land or the inner race of the outer diameter surface of the hub wheel and then cutting them. It may be a hardened steel cutting to be performed, a hardened steel cutting and a surface roughness improving finish. Hardened steel cutting is simply cutting, and since cutting is usually performed in the state of raw material, it was referred to as hardened steel cutting in order to clarify that the cutting was after heat treatment (after quenching). Surface finish improving finishing is surface finishing by super finishing, processing with an elastic grindstone, burnishing, lapping (paper wrap), or the like. Super-finishing means that fine abrasive grains are pressed against the workpiece surface with low pressure to rotate the workpiece and at the same time give fine vibration (oscillation) parallel to the workpiece surface and have excellent cleaning properties. This is a processing method in which fine cutting is performed while pouring a large amount of coolant oil to finish the surface smoothly and to obtain a highly accurate finished surface. In super-finishing, low-temperature and low-speed processing generates less heat and uses a large amount of metalworking oil, so the work-affected layer is removed, and therefore the finished surface has wear resistance, corrosion resistance, and lubricity. It is excellent, and a great effect can be obtained when it is used on a part that is subject to wear. The elastic grindstone is obtained by bonding hard abrasive grains such as diamond particles and CBN abrasive grains as a lapping material, or ordinary abrasive grains such as GC and WA with a polyurethane resin. Burnishing is a method of crushing unevenness of the surface roughness of a metal workpiece with a hard sphere or cylindrical tool to finish it into a smooth mirror surface. In lapping, a workpiece is placed on a flat table called a lapping platen, a lapping agent (diamond slurry) is sandwiched between the lapping platen and the bottom surface of the workpiece, and pressure is applied to the workpiece from above. It is a polishing method performed by moving.

  A third wheel bearing device according to the present invention is a wheel bearing device including a hub integrated outer ring having an outer race formed on an inner diameter surface and an inner ring having an inner race formed on an outer diameter surface. The outer ring has a wheel mounting flange, and the outer race and the wheel mounting flange in the hub-integrated outer ring are continuously subjected to surface machining on the same axis.

  According to the third wheel bearing device of the present invention, since the outer race and the wheel mounting flange in the hub integrated outer ring are subjected to surface machining on the same axis, the machining center (rotation) at the time of inner race machining is provided. Center misalignment between the center) and the processing axis (rotation center) during processing of the wheel mounting flange can be avoided.

  Further, the surface processing of the inner diameter surface of the hub integrated outer ring in the third wheel bearing device may be hardened steel cutting in which a hardened portion is formed on the outer race of the inner diameter surface of the hub integrated outer ring and then the outer race is cut. , Hardened steel cutting and surface roughness improvement processing finish.

  In each wheel bearing device, surface treatment of the wheel mounting flange is performed by forming a hardened portion at the base portion on the outboard side and then out of the end surface on the outboard side of the wheel mounting flange or the pilot portion protruding to the outboard side. It is preferable that the cutting is performed on the radial surface.

In the first and second wheel bearing devices of the present invention, misalignment between the machining axis (rotation center) when machining the inner race and the machining axis (rotation center) when machining the wheel mounting flange is avoided. can do. For this reason, the surface runout accuracy of the end face of the flange can be increased and the occurrence of brake judder can be suppressed.

  When the inner race of the hub wheel cuts the hardened steel, it is not necessary to perform grinding for finishing these portions. For this reason, it is possible to refrain from using environmentally unfavorable grinding coolant, enabling environmentally friendly processing and reducing costs. Moreover, the site | part in which the hardened layer was formed is excellent in abrasion resistance, lifetime resistance, etc., and becomes a high quality wheel bearing apparatus. If the surface roughness is improved and finished after cutting hardened steel, the inner race and the like are processed into a smooth surface and excellent in torque transmission. By forming the hardened layer, it is possible to improve the wear resistance of the seal land with which the seal lip of the seal member is slidably contacted, and to improve the creep resistance and the fretting resistance. Moreover, since the seal land is processed into a smooth surface, it is possible to prevent the seal function from being deteriorated.

  In the third wheel bearing device of the present invention, it is possible to avoid misalignment between the machining axis (rotation center) when the outer race is machined and the machining axis (rotation center) when the wheel mounting flange is machined. . For this reason, the surface runout accuracy of the end face of the flange can be increased and the occurrence of brake judder can be suppressed.

  Since the outer race of the hub-integrated outer ring cuts the hardened steel, it is not necessary to perform grinding for finishing these portions. For this reason, it is possible to refrain from using environmentally unfavorable grinding coolant, enabling environmentally friendly processing and reducing costs.

  Surface processing of the wheel mounting flange is done by finishing hardened steel to the end surface on the outboard side of the wheel mounting flange or the outer diameter surface of the pilot portion protruding to the outboard side. There is no need to grind. For this reason, it is possible to refrain from using environmentally unfavorable grinding coolant, enabling environmentally friendly processing and reducing costs.

  In the case of cutting the brake rotor mounting surface, base portion and pilot outer diameter surface of the wheel mounting flange, the brake rotor can be mounted with high accuracy and stability. In addition, if a hardened layer is formed at the base, the strength of the outboard side base that is the weakest part of rotational bending fatigue can be increased.

It is sectional drawing of the wheel bearing apparatus which shows 1st Embodiment of this invention. It is sectional drawing of the hub ring of the wheel bearing apparatus of the said FIG. It is sectional drawing of the wheel bearing apparatus which shows 2nd Embodiment of this invention. It is sectional drawing of the wheel bearing apparatus which shows 3rd Embodiment of this invention. It is sectional drawing of the outer ring | wheel of the wheel bearing apparatus of the said FIG. It is sectional drawing of the conventional wheel bearing apparatus.

Hereinafter, embodiments of the present invention will be described with reference to FIGS. FIG. 1 shows a wheel bearing device according to a first embodiment. This wheel bearing device is a third generation for a drive wheel, and includes a hub wheel 1 and a double row rolling bearing 2.

  The hub wheel 1 has a cylindrical portion 20 and a flange (wheel mounting flange) 21 provided at the end of the cylindrical portion 20 on the side opposite to the joint. A short cylindrical pilot portion 45 on which a wheel and a brake rotor (not shown) are mounted is projected from an end face on the outboard side of the hub wheel 1. The pilot portion 45 includes a large-diameter first portion 45a and a small-diameter second portion 45b. A wheel is externally fitted to the second portion 45b, and a brake rotor is externally fitted to the first portion 45a. A bolt mounting hole 32 is provided in the flange 21 of the hub wheel 1, and a hub bolt 33 for fixing the wheel and the brake rotor to the flange 21 is mounted in the bolt mounting hole 32. The side closer to the outside of the vehicle in the state assembled to the vehicle is called an outboard side (left side in the drawing), and the side closer to the center is called an inboard side (right side in the drawing).

  A shaft portion of the outer ring as an outer joint member of a constant velocity universal joint (not shown) is inserted into the hole portion 22 of the cylindrical portion 20 of the hub wheel 1. A male serration is formed on the shaft portion, and a female serration 42 is formed on the inner peripheral surface (inner diameter surface) of the cylindrical portion 20 of the hub wheel 1. For this reason, when the shaft portion is inserted into the tubular portion 20 of the hub wheel 1, the male serration on the shaft portion side and the female serration 42 on the hub wheel 1 side are engaged. The hub wheel 1 is made of, for example, medium carbon steel containing 0.40 to 0.80 wt% of carbon such as S53C.

  The rolling bearing 2 includes an inner ring 24 fitted to a small diameter step portion 23 provided on the joint side of the tube portion 20 of the hub wheel 1, and an outer ring 25 as an outer member fitted to the tube portion 20 of the hub wheel 1. With. The outer ring 25 is provided with two rows of outer rolling surfaces (outer races) 26 and 27 on the inner periphery thereof, and a first inner rolling surface provided on the outer periphery of the first outer rolling surface 26 and the shaft portion of the hub wheel 1 ( The inner race) 28 is opposed to the second outer rolling surface 27, and the second inner rolling surface (inner race) 29 provided on the outer peripheral surface of the inner ring 24 is opposed to each other as a rolling element 30 therebetween. Ball is inserted. That is, the rolling bearing 2 having the inner races 28 and 29 with a part of the hub wheel 1 (outer diameter surface of the cylindrical portion 20) and the inner ring 24 press-fitted into the outer periphery of the end portion of the hub wheel 1 on the inboard side. The inward member is comprised. The rolling element 30 is rotatably held by a retainer 34 interposed between the outer races 26 and 27 and the inner races 28 and 29. In addition, seal members S and S are attached to both openings of the outer ring 25.

  A vehicle body mounting flange 36 having a screw hole 35 is formed on the outer diameter surface of the outer ring 25. The outer diameter surface on the inboard side of the vehicle body mounting flange 36 is a fitting surface 37 that is fitted into a knuckle (not shown).

  In this case, the end of the hub wheel 1 on the joint side is swaged, and the swaged portion 31 is pressed against the end surface 24 a of the inner ring 24, thereby applying a preload to the inner member (inner ring) 24. As a result, the inner ring 24 can be fastened to the hub wheel 1. At this time, the end surface 24 a of the inner ring 24 is in contact with the notch end surface 23 a of the notch portion (small diameter step portion) 23.

  By the way, the hub wheel 1 is provided with a hardened layer H (H1, H2) as shown in FIG. That is, the hardened layer H1 is formed at the corner extending from the outboard side base portion 50 of the flange (wheel mounting flange) 21, that is, the first portion 45a of the cylindrical pilot portion 45 from the brake rotor mounting surface 21a, and the seal land A hardened layer H <b> 2 is formed in a region extending from 51 (the seal mounting portion on which the seal member S on the outboard side is mounted) through the rolling surface (inner race) 28 to the small-diameter step portion (notch portion) 23.

  The hardened layer H <b> 2 is not formed up to the inboard side end of the small diameter step portion 23. This is because in this wheel bearing device, the end portion on the inboard side of the hub wheel 1 is crimped to the outer diameter side, so that cracking due to this crimping is prevented.

  A hardened layer may be formed on the surface of the female serration 42 formed on the inner diameter surface of the hole 22 of the hub wheel 1. Further, the hole portion 22 of the hub wheel 1 is formed with a large diameter portion 22a corresponding to the base portion of the shaft portion in the opening portion on the inboard side, and a female serration 42 is formed in addition to the large diameter portion 22a. .

  The inner ring 24 and the outer ring 25 are made of, for example, medium carbon steel containing 0.40 to 0.80 wt% of carbon such as S53C. Further, hardened layers H4 and H5 are formed on the surfaces of the rolling surfaces 26 and 27 of the outer ring 25. The hardness of each hardened layer H (H1, H2, H4, H5) is about 50 to 65 in HRC.

  As the curing process, induction hardening, carburizing and quenching are performed. Quenching by high-frequency heating is a quenching method that applies the principle of heating a conductive object by placing Joule heat in a coil through which high-frequency current flows, and generating Joule heat by electromagnetic induction. is there. Carburizing and quenching is a process in which carbon is impregnated from the surface layer (carburizing treatment) by heating the steel in a carburizing agent such as activated carbon-rich gas, liquid or solid for a long time. It is a method of quenching and tempering steel.

  Each hardened layer H is formed by cutting hardened steel that performs cutting after quenching. Hardened steel cutting is simply cutting, and since cutting is usually performed in the state of raw material, it was referred to as hardened steel cutting in order to clarify that the cutting was after heat treatment (after quenching). Since cutting is performed after quenching, the heat treatment deformation of the material can be removed in this cutting process. When quenching, tensile residual stress tends to remain, and fatigue strength decreases as it is. For this reason, if the surface is cut, a compressive residual stress can be given to the outermost surface portion, thereby improving the fatigue strength.

  A cutting tool 54 (see FIG. 2) capable of such cutting is used as a cutting tool. For example, a sintered tool obtained by adding a special ceramic binder to CBN (cubic boron nitride) can be used as the cutting tool 54 capable of cutting hardened steel. In this case, while holding the hub wheel 1 with a cutting device and rotating the hub wheel 1 around the axis, the tool 54 is moved from the seal land 51 through the rolling surface 28 to the small-diameter step portion (see FIG. 2). The area extending to the notch 23) is moved. In this quenching cutting, the end 38 on the inboard side of the hub wheel 1 is not crimped, and the hardened steel cutting by the cutting tool 54 is performed on the end of the hub wheel 1 on the inboard side. Up to 38 edges.

  By the way, when cutting with the cutting tool 54 is performed up to the edge of the end portion 38 on the inboard side of the hub wheel 1, the cutting resistance is reduced between the hardened layer H2 and the portion where the hardened layer H2 is not formed (non-hardened layer portion). Is different. Therefore, as a cutting device (for example, an NC lathe), the cutting force is reduced by applying vibration to the cutting tool (bite 54), and the difference in cutting resistance between the hardened layer H2 and the non-hardened layer portion is reduced. It is preferable to change the machining conditions by detecting cutting power.

  Further, the outer diameter surfaces of the brake rotor mounting surface 21a, the root portion 50, and the pilot portion 45 are also cut by the cutting tool 54a. For this reason, hardened steel cutting is performed at the base 50.

  In this case, the cutting on the brake rotor mounting surface 21a side of the hub wheel 1 and the cutting on the outer diameter surface side of the cylindrical portion 20 of the hub wheel 1 are finished on the same axis (cutting). That is, the cutting on the brake rotor mounting surface 21a side of the hub wheel 1 and the cutting on the outer diameter surface side of the cylindrical portion 20 of the hub wheel 1 are performed by the same cutting device (for example, an NC lathe). In this case, in both processes, the so-called one chuck that does not release the chucked state of the hub wheel 1 is continuously performed. In the case shown in FIG. 2, the inner surface is chucked.

  Further, the hardened steel is also cut on the rolling surfaces 26 and 27 of the outer ring 25. That is, for example, the rolling surfaces 26 and 27 are cut using a tool made of the sintered body tool or the like.

  As described above, after the hardened steel is cut, the surface finish is improved on the cut surface (in particular, the seal land 51 of the hub wheel 1, the inner board 28, and the outer races 26 and 27 of the outer ring 25). Do. Surface finish improving finishing is surface finishing by super finishing, processing with an elastic grindstone, burnishing, lapping (paper wrap), or the like. Super-finishing means that fine abrasive grains are pressed against the workpiece surface with low pressure to rotate the workpiece and at the same time give fine vibration (oscillation) parallel to the workpiece surface and have excellent cleaning properties. This is a processing method in which fine cutting is performed while pouring a large amount of coolant oil to finish the surface smoothly and to obtain a highly accurate finished surface. In super-finishing, low-temperature and low-speed processing generates less heat and uses a large amount of metalworking oil, so the work-affected layer is removed, and therefore the finished surface has wear resistance, corrosion resistance, and lubricity. It is excellent, and a great effect can be obtained when it is used on a part that is subject to wear. The elastic grindstone is obtained by bonding hard abrasive grains such as diamond particles and CBN abrasive grains as a lapping material, or ordinary abrasive grains such as GC and WA with a polyurethane resin. Burnishing is a method of crushing unevenness of the surface roughness of a metal workpiece with a hard sphere or cylindrical tool to finish it into a smooth mirror surface. In lapping, a workpiece is placed on a flat table called a lapping platen, a lapping agent (diamond slurry) is sandwiched between the lapping platen and the bottom surface of the workpiece, and pressure is applied to the workpiece from above. It is a polishing method performed by moving.

  In the present invention, misalignment between the machining axis (rotation center) when machining the inner race 28 and the machining axis (rotation center) when machining the wheel mounting flange 21 can be avoided. For this reason, the surface runout accuracy of the end face of the flange can be increased and the occurrence of brake judder can be suppressed.

  Further, the seal land 51 to the inner race 28 on the outer diameter surface of the hub wheel 1, the inner ring fitting surface (the outer diameter surface of the small diameter step portion 23), and the outer races 26 and 27 of the outer ring 25 are hardened steel cut. This eliminates the need for grinding to finish these parts. For this reason, it is possible to refrain from using environmentally unfavorable grinding coolant, enabling environmentally friendly processing and reducing costs.

  And the site | part in which the hardened layer H was formed is excellent in abrasion resistance, lifetime resistance, etc., and becomes a high quality wheel bearing apparatus. In particular, by forming the hardened layer H1, it is possible to increase the strength of the outboard side root that is the weakest part of rotational bending fatigue. By forming the hardened layer H2, it is possible to improve the wear resistance of the seal land 51 with which the seal lip of the seal member S is in sliding contact, and to improve the creep resistance and the fretting resistance.

  In particular, since the outer races 26 and 27, the inner race 28, and the like are subjected to surface roughness improving finishing after cutting hardened steel, they are excellent in torque transmission and can have a long life. Further, since the seal land 51 is processed to have a smooth surface, it is possible to prevent the seal function from being lowered.

  Next, FIG. 3 shows a second embodiment. In this case, a fourth generation wheel bearing device in which an inner race 29 on the inboard side is formed on the outer diameter surface of the outer ring 5 as an outer joint member of the constant velocity universal joint 3. It is.

  A hardened layer H3 formed by induction hardening or the like is provided on the outboard side of the inner diameter surface of the hub wheel 1, and an uneven portion 56 is formed in the hardened layer H3. The concavo-convex portion 56 is formed in the shape of an iris knurl, a cross groove formed by substantially orthogonally crossing a plurality of annular grooves formed independently by turning or the like and a plurality of axial grooves formed by broaching or the like, Or it consists of the crossing groove | channel comprised by the helical groove | channel inclined mutually. Further, in order to ensure good biting property, the tip of the concavo-convex portion 56 is formed in a spire shape such as a triangular shape.

  The constant velocity universal joint 3 includes an outer ring 5 as an outer joint member, an inner ring (not shown) as an inner joint member disposed in the mouth portion 11 of the outer ring 5, and the inner ring and the outer ring 5. A ball (not shown) to be disposed and a cage (not shown) for holding the ball are provided. The outer ring 5 includes the mouse portion 11, a shoulder portion 13 that forms the bottom of the mouse portion 11, and a shaft portion 12. A seal land 64 to which the inboard-side seal member S is mounted and an inner race 29 are formed on the outer diameter surface of the shoulder portion 13.

  In addition, the shaft portion 12 has an inrow portion 60a fitted to an end portion on the inboard side of the hub wheel 1 through a predetermined allowance, and an outboard side fit fitted to the uneven portion 56 of the hub wheel 1. A joint portion 60b is formed. Then, in a state where the shaft portion 12 is fitted into the hub wheel 1 and the outer ring 5 and the hub wheel 1 are integrated, the end surface 13a of the shoulder portion 13 and the end surface 62 on the inboard side of the hub wheel 1 contact each other. Touch.

  Also in this case, the outer diameter surface of the hub wheel 1 is hardened in a region extending from the seal land 51 (the seal mounting portion where the seal member S on the outboard side is mounted) through the rolling surface 28 to the edge on the inboard side. Layer H2 is formed. Although not shown in the figure, it is preferable to form the hardened layer H1 at the root (corner) 50 extending from the brake rotor mounting surface 21a to the first portion 45a of the cylindrical pilot portion 45.

  A hardened layer H (H6) is formed on the outer diameter surface of the outer ring 5 of the constant velocity universal joint 3 from the outer diameter surface of the shoulder portion 13 to the inboard side of the outer diameter surface of the shaft portion 12. That is, the hardened layer H6 is formed in a range from the seal land 64 of the shoulder portion 13 to the inner race 29 and the inner wax portion 60a. A hardened layer H (H3) is formed on the bottom surface of the ball groove 59 on the inner diameter surface of the outer ring 5. The outer ring 25 of the bearing 2 is the same as the outer ring 25 shown in FIG.

  Also in this wheel bearing device, the seal land 51 of the hub wheel 1, the inner race 28, the outer races 28 and 29 of the outer ring 25 of the bearing 2, the inner race 29 of the outer ring 5 of the constant velocity universal joint 3, and the seal land 64 are Hardened steel cutting that performs cutting after quenching and surface roughness improvement processing finish are made. In addition, the inner race and the wheel mounting flange in the hub wheel are subjected to surface machining on the same axis. For this reason, this wheel bearing device also has the same effects as the wheel bearing device shown in FIG.

  Next, FIG. 4 shows a second generation outer ring rotating type, which is a hub-integrated outer ring 65 having outer races 66 and 67 formed on the inner diameter surface, and a pair of inner rings 72A having inner races 70 and 71 formed on the outer diameter surface. 72B. Between the outer races 66 and 67 and the inner races 70 and 71, a rolling element 92 held by a cage 93 is interposed.

  That is, the inner ring 72 (72 </ b> A, 72 </ b> B) includes a large diameter portion 73, a small diameter portion 74, and a tapered portion 75 between the large diameter portion 73 and the small diameter portion 74. In this case, the outer diameter surface of the large diameter portion 73 becomes the seal mounting surface 77, and the outer diameter surface of the tapered portion 75 becomes the rolling surfaces (inner races) 70 and 71.

  The hub-integrated outer ring 65 includes a cylindrical main body portion 80 and a flange (wheel mounting flange) 81 that protrudes from the outer diameter surface of the cylindrical main body portion 80 on the outboard side in the outer diameter direction. The pilot portion 82 is projected from the end face of the main body portion 80 on the outboard side. A hole 83 into which the hub bolt 33 is inserted is formed in the flange 81. And the shoulder part 87 (refer FIG. 5) of the outer-board-side edge part of the inner surface of the outer ring 65 is a seal mounting part 88, and the in-board side edge part is a seal mounting part 89. For this reason, the seal members S are mounted between the seal mounting surfaces 77 and 77 of the inner rings 72A and 72B and the seal mounting portions 88 and 89 of the hub integrated outer ring 65, respectively.

  As shown in FIG. 5, hardened layers H <b> 8 and H <b> 9 are formed on the surfaces of the rolling surfaces 66 and 67 of the outer ring 65, and a hardened layer H <b> 10 is formed on the flange root 91. Also in this case, the hardened layers H8, H9, and H10 are formed by cutting hardened steel that performs cutting after quenching. Furthermore, the hardened layers H8 and H9 are subjected to surface roughness improving processing finish.

The inner surface of the outer ring 65 is cut using a cutting tool 85 made of, for example, the sintered body tool. In this case, while holding the outer ring 65 with a cutting device and rotating the outer ring 65 around the axis, the bit 85 is at least the outer race 67 on the inboard side and the distance between the races as indicated by the dotted arrows in FIG. The shoulder portion 86, the outer race 66 on the outboard side, and the shoulder portion 87 on the outboard side of the outer race 66 are moved. The outboard side seal mounting portion 88 and the inboard side seal mounting portion 89 of the inner surface of the outer ring 65 are subjected to surface roughness improving finishing.

  Further, the end surface (brake rotor mounting surface) 81a of the flange 81 (brake rotor mounting surface) 81, the root portion 91, and the outer diameter surface 84 of the pilot portion 82 are cut with a cutting tool 90 made of, for example, the sintered body tool.

  The cutting on the brake rotor mounting surface 81a side of the outer ring 65 and the cutting of the inner diameter surface of the outer ring 65 are finished on the same axis (cutting). That is, the cutting on the brake rotor mounting surface 81a side of the outer ring 65 and the cutting on the inner diameter surface side of the outer ring 65 are performed by the same cutting device. In this case as well, in both steps, the so-called one chuck that does not release the chucked state of the hub wheel 1 is continuously performed.

  For this reason, misalignment between the machining axis (rotation center) when machining the outer races 66 and 67 and the machining axis (rotation center) when machining the wheel mounting flange 81 can be avoided, and the end face of the flange can be avoided. The occurrence of brake judder can be suppressed by increasing the surface runout accuracy. The outer races 66 and 67 and the seal mounting portions 88 and 89 are finished with a surface roughness improving process after cutting hardened steel. For this reason, even if it is the wheel bearing apparatus shown in FIG. 4, even if it is the wheel bearing apparatus shown in FIG. 4, there exists an effect similar to the wheel bearing apparatus shown in the said FIG.

  The wheel bearing device according to the present invention can be applied to various types. That is, it may be used for a drive wheel or a driven wheel (the hub wheel 1 has a solid shaft member). ) Or an outer ring rotating type (a type in which the outer member side of the bearing 2 rotates). As shown in FIG. 1, when the hub wheel 1 is for a drive wheel having a cylindrical portion 20, a screw provided at the tip of the shaft portion as means for fixing the shaft portion of the outer ring 5 of the constant velocity universal joint 3 Even if the nut member is screwed to the portion, the tip end portion of the shaft portion of the outer ring 5 may be swaged and engaged with the hub wheel 1. Further, a male spline is provided on the outer diameter surface of the shaft portion of the outer ring 5, and the shaft portion of the outer ring 5 is press-fitted into the cylindrical portion 20 of the hub wheel 1 in a state where no female spline is provided on the inner diameter surface. Also good. Further, the outer ring 5 of the constant velocity universal joint 3 may have a cylindrical shaft portion, and the boss portion of the hub wheel 1 may be fitted into the cylindrical shaft portion.

  As described above, the embodiments of the present invention have been described. However, the present invention is not limited to the above-described embodiments, and various modifications are possible. For example, in the case of forming a hardened layer, in the above-described embodiments, high-frequency heat treatment is used. However, it may be performed by laser heat treatment. Laser quenching is a method in which a surface of a steel part is irradiated with a laser beam having a high energy density and heated, and is quenched and hardened by a self-cooling action. There are various types of laser oscillation devices such as a carbon dioxide laser, YG laser, plasma laser, and excimer laser. In this case, for example, a carbon dioxide laser can be used. Heating by the laser beam is extremely rapid, and quenching is self-cooling without using a coolant. For this reason, laser quenching has the advantage that local quenching can be performed in a small area in a short time and distortion is less likely to occur. Moreover, it is not necessary to perform tempering after quenching.

  Incidentally, in the embodiment shown in FIG. 1, a hardened layer provided on the inner diameter surface side of the hub wheel 1 may be provided. The hardened layer may be formed over substantially the entire length of the female serration 42, or such a hardened layer may be provided only on the inboard side. When the hardened layer is provided over substantially the entire length of the female serration 42, a stable serration fitting can be formed, and a high-quality product can be provided. When excessive torque is generated, a large load is applied to the inboard side in the serration formed in the hole of the hub wheel. For this reason, if a hardened layer is provided at least on the inboard side in the serration, it is possible to sufficiently cope with such an excessive torque.

  In addition, it is possible to form a smooth surface that functions as a rolling surface without cutting the outer surface or inner race without performing surface roughness improvement finishing. A mark) may be formed. For this reason, when the surface roughness improvement processing finish is not performed, the hardened steel cutting is performed by cutting with a general shape tool so that tool marks are not generated on the raceway surfaces (outer races 26, 27, inner race 28, etc.). It is also possible. The general shape tool is a tool having a certain contour, and can cut (total shape) a workpiece into the same shape as the contour. For this reason, if hardened steel cutting is performed with such a total shape tool, tool marks (cut marks) are not generated in the outer race and the inner race.

DESCRIPTION OF SYMBOLS 1 Hub wheel 2 Bearing 3 Constant velocity universal joint 21 Wheel mounting flange 24 Inner ring 26, 27 Outer race 28, 29 Inner race 30 Rolling element 45 Pilot part 51 Seal land 65 Hub integrated outer ring 66, 67 Outer race 70, 71 Inner race 72A, 72B Inner ring 80 Main part 81 Wheel mounting flange 82 Pilot part

Claims (7)

A bearing having a plurality of rows of rolling elements arranged between opposing outer races and inner races, and a hub wheel attached to the wheel are provided, and an inner race on the outboard side is formed on the outer diameter surface of the hub wheel. A wheel bearing device in which an inner race on the inboard side is formed on the inner ring fitted on the inboard side of the outer diameter surface of the hub wheel,
The hub wheel has a wheel mounting flange, and the inner race and the wheel mounting flange in the hub wheel are continuously subjected to surface machining on the same axis. A bearing having a plurality of rows of rolling elements arranged between opposing outer races and inner races, and a hub wheel attached to the wheel are provided, and an inner race on the outboard side is formed on the outer diameter surface of the hub wheel. A wheel bearing device in which an inner race on the inboard side is formed on the outer diameter surface of the outer joint member of the constant velocity universal joint connected to the hub wheel,
The hub wheel has a wheel mounting flange, and the inner race and the wheel mounting flange in the hub wheel are continuously subjected to surface machining on the same axis.   The surface processing of the outer diameter surface of the hub wheel is a hardened steel cutting in which a hardened portion is formed on at least a seal land or an inner race of the outer diameter surface of the hub wheel, and then the cutting is performed on these. The wheel bearing device according to claim 1 or 2.   The surface processing of the outer diameter surface of the hub wheel is performed by forming a hardened portion on at least the seal land or the inner race of the outer diameter surface of the hub wheel, and thereafter cutting the hardened steel and surface roughness improvement processing. The wheel bearing device according to claim 1, wherein the wheel bearing device is a wheel bearing device. A wheel bearing device comprising a hub-integrated outer ring having an outer race formed on an inner diameter surface and an inner ring having an inner race formed on an outer diameter surface,
The hub integrated outer ring has a wheel mounting flange, and the outer race and the wheel mounting flange in the hub integrated outer ring are continuously subjected to surface machining on the same axis.   6. The surface machining of the inner diameter surface of the hub integrated outer ring is a hardened steel cutting in which a hardened portion is formed on the outer race of the inner diameter surface of the hub integrated outer ring and then the outer race is cut. Wheel bearing device.   The surface processing of the inner surface of the hub-integrated outer ring is a hardened steel cutting and surface roughness improvement processing finish that cuts the outer race of the inner surface of the hub-integrated outer ring after forming a hardened portion. The wheel bearing device according to claim 5.

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