JP5890636B2 - Wheel bearing device - Google Patents

Description

  The present invention relates to a wheel bearing device that rotatably supports a wheel of an automobile or the like with respect to a suspension device.

  2. Description of the Related Art Wheel bearing devices for vehicles such as automobiles include those for driving wheels and those for driven wheels. In particular, a wheel bearing device that rotatably supports a wheel with respect to a suspension device of an automobile has been reduced in weight for improving fuel consumption, not to mention cost reduction.

  In a conventional wheel bearing device, a double row outer rolling surface is formed on the inner periphery of the outer member, and a shoulder is formed between the double row outer rolling surfaces. When the vehicle is turning, the rolling element may tilt inside the bearing due to the moment load from the tire, and the rolling element may pass through the shoulder of the outer rolling surface. This type of outer member is made of, for example, medium carbon steel such as S53C, and a predetermined hardened layer is formed by induction hardening on at least the double row outer raceway surface. Even if the heat treatment conditions and the shape / dimensions of the chamfered part are sufficiently controlled so as to prevent the crystal grains from being overheated, the crystal grains may be coarsened. When the structure becomes coarse, the rolling fatigue life is reduced. In addition, when riding on the shoulder, there was a limit in trying to take measures against the short life due to edge loading with the shape of the shoulder. Here, shoulder climbing refers to a phenomenon in which the contact ellipse of the ball deviates from the outer rolling surface, and edge load is an excessive stress concentration occurring at the corners, etc. Says the phenomenon that becomes one.

  Therefore, the present applicant has proposed a wheel bearing device that solves these problems. As shown in FIG. 14A, the outer member 51 of the wheel bearing device has a cylindrical shoulder portion 52 formed by forging between the double row outer rolling surfaces 51a and 51b. After the outer rolling surfaces 51a and 51b are turned, a hardened layer 53 is formed with a surface hardness in the range of 58 to 64 HRC by induction hardening (indicated by cross hatching in the figure). An annular notch 54 is formed by quenching steel cutting from the double row outer raceway surfaces 51 a and 51 b to the shoulder 52. As shown in (b), the notch 54 is formed to have a predetermined width so that at least the range of the hardened layer 53 is removed (indicated by a two-dot chain line in the figure). Thereby, even if the edge part 55 of the double row outer side rolling surfaces 51a and 51b and the shoulder part 52 overheats by induction hardening and a crystal grain coarsens and deteriorates, it can remove reliably, It is possible to prevent a short life of the bearing due to cracks and cracks (for example, see Patent Document 1).

JP 2008-261384 A

  Thus, in the conventional outer member 51, since the notch part 54 is formed in the predetermined width | variety so that all the removals in the range of the hardening layer 53 may be carried out, it is the double row outer side rolling surface 51a, 51b. Even if the edge portion 55 between the shoulder portion 52 and the shoulder portion 52 is overheated and the surface crystal grains are coarsened and deteriorated, the edge portion 55 can be surely removed, and the short life of the bearing due to cracks and chips due to burning cracks can be prevented. Can do.

  However, when the ball rides on the outer rolling surfaces 51a and 51b due to the moment load during turning of the vehicle and the long-side vertex of the contact ellipse falls off the edge portion 55, an edge load is generated, resulting in an extremely high surface pressure. Life is greatly reduced. In order to improve the fuel efficiency of automobiles, further downsizing and weight reduction of wheel bearing devices are required. In the future, it is considered that the technique of Patent Document 1 will be insufficient as a countermeasure against the occurrence of edge load. Furthermore, it is necessary to remove the hardened layer by quenching steel cutting, and the number of processes increases, resulting in high costs.

  Further, in order not to coarsen the grains, even if the vicinity of the edge portions 55 of the outer rolling surfaces 51a and 51b is not excessively heated during induction hardening, in order to cope with the high surface pressure during the turning, a certain degree A deep hardened layer is necessary, and it is difficult to form a deep hardened layer while preventing coarsening.

  Here, it is conceivable to select a steel type with good hardenability, but since the material standard is special, it is not preferable because the cost increases due to the prevention of mixing with other materials. Therefore, there is a demand for a short life countermeasure due to a high surface pressure near the edge portion 55 when the vehicle is turning while keeping the current steel grade.

  The present invention has been made in view of such conventional problems, and suppresses overheating of the shoulder portion of the outer rolling surface during heat treatment of the outer member, prevents crystal coarsening, and An object of the present invention is to provide a wheel bearing device that prevents an extreme edge load even when a rolling element protrudes from a running surface and rolls, thereby extending the life of the bearing.

In order to achieve such an object, the invention according to claim 1 of the present invention includes an outer member in which a double row outer rolling surface is integrally formed on the inner periphery, and an outer rolling of the double row on the outer periphery. An inner member in which a double row inner rolling surface facing the surface is formed, and a double row accommodated between the rolling surfaces of the inner member and the outer member via a retainer so as to roll freely. In the wheel bearing device provided with a rolling element, a cylindrical shoulder is formed between the outer rolling surfaces of the double row of the outer member, and the end of the outer rolling surface on which the rolling element rolls. A tapered surface extending from the shoulder to the shoulder, and an end of the outer rolling surface and a corner of the edge of the tapered surface are formed in an arc shape having a predetermined radius of curvature R1, R2, A radius of curvature R1 is set larger than a radius of curvature R2 of the edge portion of the tapered surface (R1> R2), and The angle of inclination of the surface is smaller than the angle formed by the tangent line of the outer rolling surface at the terminal position of the outer rolling surface and the inner diameter surface of the shoulder, and is set in a range of 30 ° to 75 °, A predetermined hardened layer is formed on the double row outer rolling surface to form a grinding surface .

Thus, in the wheel bearing device provided with the outer member in which the double row outer rolling surfaces are integrally formed on the inner periphery, the cylindrical shoulder portion between the double row outer rolling surfaces of the outer member. And a tapered surface is formed from the end of the outer rolling surface to the shoulder where the rolling element rolls, and the end of the outer rolling surface and the corner of the edge of the tapered surface have a predetermined radius of curvature R1. , R2 is formed in a circular arc shape, the curvature radius R1 on the terminal side is set larger than the curvature radius R2 of the edge portion of the tapered surface (R1> R2), and the inclination angle of the tapered surface is the outer rolling surface. Is smaller than the angle formed by the tangent line of the outer rolling surface and the inner diameter surface of the shoulder at the end position, and is set in a range of 30 ° to 75 °, and a predetermined hardened layer is formed on the double row outer rolling surface. Since it is a ground surface, it may be the end of the outer rolling surface where the rolling element rolls by the tapered surface. An edge portion is provided at a position far away from the heat source, and heat raised by induction hardening is also released in the direction of the edge portion, so that the vicinity of the end of the double row outer rolling surface can be prevented from overheating. That is, the portion where the structure is likely to coarsen due to heat is contained in the tapered surface, and the structure near the end of the outer rolling surface is not coarsened, so that the high surface pressure of the coarsened structure Short life can be prevented. Further, when the vehicle turns μ = 0.6, the rolling element protrudes beyond the height at which it does not roll, the diameter of the rolling element is Da, and the groove curvature radius Ra of the outer rolling surface is 0.51 to 0. If it is set to 54 Da, h ≦ 0.45 Da, when the rolling element protrudes from the end of the outer rolling surface and rolls, the volume receiving the load is increased, and the shoulder edge portion As compared with the above, it is possible to prevent the end corner portion of the outer rolling surface from becoming an extreme edge load.

Further, as in the invention described in claim 2 , the austenite crystal grain size within 1 mm from the surface of the hardened layer at the terminal portion of the outer rolling surface is set smaller than the austenite crystal grain size at the edge part of the tapered surface. If so, it is possible to prevent a short life due to coarsening under high surface pressure and to extend the life of the bearing.

Further, as in the invention described in claim 3 , the height h from the groove bottom at the inner diameter side of the outer rolling surface is a turning μ = 0.6 of the vehicle to which the wheel bearing device is applied. When the rolling element protrudes beyond the height where it does not roll, the diameter of the rolling element is Da, and the groove curvature radius Ra of the outer rolling surface is 0.51 to 0.54 Da, h ≦ If it is set to 0.45 Da, it is possible to prevent grinding burn in the grinding process of the outer rolling surface and to prevent the rolling element from climbing over the shoulder, thereby extending the life of the bearing.

Further, as in the invention described in claim 4, when the height H from the groove bottom of the outer rolling surface of the inner diameter surface of the shoulder portion is H ≦ 0. If it is set to 5 Da, it is possible to prevent the interference with the cage and facilitate the design and processing while maintaining the required strength of the cage.

It is preferable as defined in claim 5, wherein if a tapered MengaKen Kezumen, the oxide scale deposited by the heat treatment can reliably remove the acoustic by oxidation scale from entering the outer raceway surfaces, It is possible to prevent vibration deterioration and damage from the oxide scale biting indentation.

Further, it is possible as in the invention of claim 6, the inner diameter surface of the shoulders lever is a ground surface, to reduce the number of processing steps.

Further, as in the invention described in claim 7 , the axial depth of the hardened layer of the outer member gradually increases in the axial direction from the contact point position with the rolling element of the outer rolling surface to the shoulder. If formed in this way, a sufficient hardened layer depth corresponding to a high surface pressure during turning can be ensured, and the life of the bearing can be extended.

Further, as in the invention described in claim 8 , the outer member is formed of medium-high carbon steel containing 0.40 to 0.80% by weight of carbon, and at least the surface hardness of the outer raceway of the double row. Is set in a range of 58 to 64 HRC, a desired life can be secured.

According to a ninth aspect of the present invention, the outer member is integrated with a vehicle body mounting flange for mounting the vehicle body on the outer periphery, and the inner member is a wheel for mounting a wheel at one end. A hub wheel integrally having a mounting flange and having an inner rolling surface facing one of the outer rolling surfaces of the double row on the outer periphery, and a small-diameter step portion extending in the axial direction from the inner rolling surface; and The inner ring may be formed of an inner ring that is fixed to the small-diameter step portion of the hub wheel and has an inner rolling surface facing the other of the double row outer rolling surfaces on the outer periphery.

Further, as in the invention according to claim 10 , the outer member has a vehicle body mounting flange for mounting the vehicle body on the outer periphery, and the inner member has a wheel for mounting a wheel at one end. A hub wheel integrally having a mounting flange and having an inner rolling surface facing one of the outer rolling surfaces of the double row on the outer periphery, and a small-diameter step portion extending in the axial direction from the inner rolling surface; and This outer joint is composed of an outer joint member of a constant velocity universal joint that is fitted to the small-diameter step portion of the hub wheel and has an inner rolling surface facing the other of the outer rolling surfaces of the double row on the outer periphery. The member and the hub ring may be integrally plastically coupled.

The wheel bearing device according to the present invention includes an outer member in which a double row outer rolling surface is integrally formed on an inner periphery, and a double row inner rolling that faces the outer rolling surface of the double row on an outer periphery. A wheel bearing comprising: an inner member having a surface formed therein; and a double-row rolling element that is rotatably accommodated between both rolling surfaces of the inner member and the outer member via a cage. In the apparatus, a cylindrical shoulder portion is formed between the outer rolling surfaces of the double row of the outer member, and a tapered surface is formed from the end of the outer rolling surface where the rolling element rolls to the shoulder portion. In addition, the end of the outer rolling surface and the corner of the edge of the tapered surface are formed in an arc shape having predetermined curvature radii R1 and R2, and the curvature radius R1 on the end is the edge of the tapered surface. Larger than the radius of curvature R2 (R1> R2), and the inclination angle of the taper surface is Smaller than the angle made by the inner surface of the tangent and the shoulder of the outer raceway surfaces at the end position of the surface, is set within a range of 30 ° to 75 °, predetermined curing the outer raceway surfaces of the double row Since the layer is formed and used as the grinding surface , an edge is provided at a position away from the end of the outer rolling surface where the rolling element rolls due to the tapered surface, and the heat raised by induction hardening is applied to this edge. It is also possible to prevent the overheating of the vicinity of the end of the double row outer rolling surface. That is, the portion where the structure is likely to coarsen due to heat is contained in the tapered surface, and the structure near the end of the outer rolling surface is not coarsened, so that the high surface pressure of the coarsened structure Short life can be prevented. Further, when the vehicle turns μ = 0.6, the rolling element protrudes beyond the height at which it does not roll, the diameter of the rolling element is Da, and the groove curvature radius Ra of the outer rolling surface is 0.51 to 0. If it is set to 54 Da, h ≦ 0.45 Da, when the rolling element protrudes from the end of the outer rolling surface and rolls, the volume receiving the load is increased, and the shoulder edge portion As compared with the above, it is possible to prevent the end corner portion of the outer rolling surface from becoming an extreme edge load.

It is a longitudinal section showing a 1st embodiment of a bearing device for wheels concerning the present invention. It is an expanded sectional view which shows the outer member single-piece | unit of FIG. FIG. 3 is an enlarged view of a main part of FIG. 2. It is a principal part enlarged view which shows the modification of FIG. It is explanatory drawing which shows the hardened layer of the outward member of FIG. It is a longitudinal cross-sectional view which shows 2nd Embodiment of the wheel bearing apparatus which concerns on this invention. It is a longitudinal cross-sectional view which shows 3rd Embodiment of the wheel bearing apparatus which concerns on this invention. It is a longitudinal cross-sectional view which shows 4th Embodiment of the wheel bearing apparatus which concerns on this invention. It is a longitudinal cross-sectional view which shows 5th Embodiment of the wheel bearing apparatus which concerns on this invention. It is a longitudinal cross-sectional view which shows 6th Embodiment of the wheel bearing apparatus which concerns on this invention. It is an expanded sectional view which shows the outward member single-piece | unit of FIG. It is a longitudinal cross-sectional view which shows 7th Embodiment of the wheel bearing apparatus which concerns on this invention. It is an expanded sectional view which shows the outer member single-piece | unit of FIG. (A) is an expanded sectional view which shows the outer member single-piece | unit of the conventional wheel bearing apparatus, (b) is a principal part enlarged view of (a).

  An outer member integrally having a vehicle body mounting flange to be attached to the vehicle body on the outer periphery, a double row outer rolling surface formed integrally on the inner periphery, and a wheel mounting flange for mounting a wheel on one end A hub wheel integrally formed and having an inner rolling surface facing one of the outer rolling surfaces of the double row on the outer periphery, and a small-diameter step portion extending in the axial direction from the inner rolling surface, and the hub wheel An inner member made of an inner ring that is press-fitted into a small-diameter step portion of the inner diameter through a predetermined squeeze and has an inner rolling surface that faces the other of the outer rolling surfaces of the double row on the outer periphery, and the inner member In a wheel bearing device comprising a double row of balls accommodated so as to roll freely between both rolling surfaces of the outer member via a cage, between the outer rolling surfaces of the double row of the outer member A cylindrical shoulder is formed on the outer rolling surface where the rolling element rolls. A notch is formed into a tapered surface, and the end of the outer rolling surface and the corner of the edge of the notch are formed in an arc shape having a predetermined radius of curvature R1, R2, and the end side Is set to be larger than the curvature radius R2 of the edge portion of the notch (R1> R2), the outer rolling surfaces of the double row are turned, and then a predetermined hardened layer is formed by induction hardening. After that, the double row outer rolling surfaces are finished to a predetermined shape and surface roughness by grinding and superfinishing.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a longitudinal sectional view showing a first embodiment of a wheel bearing device according to the present invention, FIG. 2 is an enlarged sectional view showing a single outer member of FIG. 1, and FIG. 3 is a main portion of FIG. FIG. 4 is an enlarged view, FIG. 4 is an enlarged view of a main part showing a modification of FIG. 3, and FIG. 5 is an explanatory view showing a hardened layer of the outer member 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 called the third generation for driven wheels, and is a double row rolling element (ball) accommodated between the inner member 1 and the outer member 2 and between the members 1 and 2 so as to roll freely. 3 and 3. The inner member 1 includes a hub ring 4 and an inner ring 5 press-fitted into the hub ring 4 through a predetermined shimiro.

  The hub wheel 4 integrally has a wheel mounting flange 6 for attaching a wheel (not shown) to an end portion on the outer side, and a hub bolt for fixing the wheel at a circumferentially equidistant position of the wheel mounting flange 6. 6a is planted. Further, one (outer side) inner rolling surface 4a is directly formed on the outer periphery of the hub wheel 4, and a small-diameter step portion 4b extending in the axial direction from the inner rolling surface 4a is formed. And the inner ring | wheel 5 by which the inner side rolling surface 5a of the other (inner side) was formed in the outer periphery is press-fit in this small diameter step part 4b, and also the edge part of the small diameter step part 4b is plastically deformed to radial direction outward. The inner ring 5 is fixed to the hub wheel 4 in the axial direction in a state where a predetermined bearing preload is applied by the formed caulking portion 4c, thereby constituting a back-to-back type double row angular ball bearing.

  The hub wheel 4 is made of medium and high carbon steel containing carbon of 0.40 to 0.80% by weight, such as S53C, and includes a seal land portion in which an outer side inner rolling surface 4a and an outer side seal 8 described later are in sliding contact. To the small-diameter step portion 4b, the surface hardness is set to a range of 58 to 64 HRC by induction hardening. The caulking portion 4c is an unquenched portion having a surface hardness of 25HRC or less after forging. On the other hand, the inner ring 5 and the rolling element 3 are made of a 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. Thereby, not only the wear resistance of the seal land portion is improved, but also the strength of the hub wheel 4 is improved, and the fretting wear on the fitting surface of the inner ring 5 is suppressed, thereby improving the durability. Moreover, the workability of the caulking portion 4c can be improved, and the occurrence of cracks and the like due to plastic deformation can be prevented.

  The outer member 2 integrally has a vehicle body mounting flange 2b for mounting to the vehicle body (not shown) on the outer periphery, and faces the double row inner rolling surfaces 4a, 5a of the inner member 1 on the inner periphery. Double row outer rolling surfaces 2a, 2a are integrally formed. This outer member 2 is formed of medium and high carbon steel containing 0.40 to 0.80% by weight of carbon such as S53C, as with the hub wheel 4, and is formed between the rolling surfaces 2a, 4a and 2a, 5a. The rolling elements 3 and 3 in rows are accommodated, and the rolling elements 3 and 3 in double rows are held by the cages 7 and 7 so as to freely roll. Seals 8 and 9 are attached to the opening of the annular space formed between the outer member 2 and the inner member 1, and leakage of lubricating grease sealed inside the bearing and rainwater and dust from the outside. Etc. are prevented from entering the inside of the bearing.

  Here, as shown in an enlarged view in FIG. 2, the outer member 2 has a cylindrical shoulder portion 10 formed between the double row outer rolling surfaces 2a, 2a, and both end portions of the shoulder portion 10. An annular notch 11 is formed in the upper surface. Then, after the double row outer rolling surfaces 2a and 2a are turned, a hardened layer 12 is formed with a surface hardness of 58 to 64 HRC by induction hardening (the hardened layer 12 is cross-hatched in the figure). Show). After induction hardening, the double row outer rolling surfaces 2a, 2a are finished to a predetermined shape and surface roughness by grinding and superfinishing.

  The height from the groove bottom of the end 13 on the inner diameter side of the outer rolling surface 2a, the so-called groove depth h is such that the rolling element 3 protrudes when the vehicle turning μ = 0.6 to which the wheel bearing device is applied. More than the height that does not roll, preferably higher than the height at which the rolling element 3 protrudes when turning μ = 0.7 and the diameter of the rolling element 3 is Da, h ≦ 0.45 Da Has been. Thereby, it is possible to prevent the rolling element 3 from climbing over the shoulder and to extend the life of the bearing. However, the groove curvature radius Ra of the outer rolling surface 2a is 0.51 to 0.54 Da. Here, turning μ means that when the vehicle makes a turning motion, the tire generates a cornering force, that is, a force that acts on each wheel toward the center of the turning motion circle. The coefficient of friction is shown.

  The turn μ = 0.6 is a value of the turn μ that may occur sufficiently in a sudden turn, and needs to correspond to it. Further, when h ≦ 0.45 Da, when the groove depth h becomes deeper than this, when grinding the outer rolling surface 2a, if grinding is performed coaxially with the outer member 2, the vicinity of the shoulder portion 10 is a grindstone. This is because it is in a state of being processed on the side surface, and grinding burn is likely to occur. Moreover, if grinding is performed by so-called angular feed, in which the double-row outer rolling surfaces 2a, 2a are fed in a state where the grindstone is inclined in the contact angle direction one side at a time, it is difficult to be in a state of machining on the side surface of the grindstone. The accuracy of the double row outer rolling surfaces 2a, 2a, such as the coaxiality, the groove pitch dimension, and the right / left mutualness of the groove diameter, is not preferable.

  The height H from the groove bottom of the inner diameter surface of the shoulder portion 10 is set to H ≦ 0.5 Da. When the inner diameter surface of the shoulder portion 10 becomes smaller than this, not only does the interference with the cage 7 occur, but also the design and processing while maintaining the required strength of the cage 7 become difficult.

  The notch 11 is formed in a tapered surface having a predetermined inclination angle θ. In this way, the edge portion 11a is provided at a position away from the terminal end 13 of the outer rolling surface 2a where the rolling element 3 rolls by the notch portion 11, and the heat raised by induction hardening is directed to the edge portion 11a. It is also possible to prevent the over-heating of the vicinity of the terminal end 13 of the double row outer rolling surfaces 2a, 2a. That is, by storing the portion where the structure is likely to be coarsened due to heat in the notch portion 11 formed of a tapered surface, the structure in the vicinity of the terminal end 13 of the outer rolling surface 2a is not coarsened. It is possible to prevent a short life due to a high surface pressure of the coarsened structure under pressure.

  Further, when the vehicle turns μ = 0.6, the rolling element protrudes beyond the height at which it does not roll, the diameter of the rolling element is Da, and the groove curvature radius Ra of the outer rolling surface is 0.51 to 0. When 54 Da is set, h ≦ 0.45 Da is set, a notch 11 is formed in a tapered surface from the end 13 of the outer rolling surface 2 a on which the rolling element 3 rolls to the shoulder 10, and the outer rolling is performed. When the rolling element 3 protrudes from the end 13 of the running surface 2a and rolls, the volume receiving the load is increased, and the corner of the end 13 of the outer rolling surface 2a is larger than the edge 11a of the shoulder 10. An extreme edge load can be prevented.

  Here, with respect to the hardened layer 12 to be hardened, the maximum shear is obtained within 1 mm from the surface on the outer diameter side (the range of fine cross-hatching in FIG. 2) from the terminal end 13 of the outer rolling surface 2a, that is, the turning μ = 0.7. The austenite grain size number specified in JIS G0551 is within the depth that allows the stress depth to be sufficiently allowed to be on the inner diameter side from the end 13 of the outer raceway surface 2a of the hardened layer 12 (range of rough cross-hatching in FIG. 2). ), That is, larger than the austenite grain size number which is the coarsest grain within 1 mm from the surface in the vicinity of the edge portion 11a. Specifically, for the austenite grain size number which is the coarsest grain within 1 mm from the surface of the edge portion 11a of the hardened layer 12 (the grain size is about 150 μm), the end of the outer rolling surface 2a The austenite grain size number within 1 mm from the surface on the outer diameter side from 13 is refined to No. 5 (crystal grain size is about 60 μm). As a result, the life of the bearing can be extended.

  The inclination angle θ of the notch 11 is an angle α formed by the tangent line 14 of the outer rolling surface 2a and the inner diameter surface of the shoulder 10 at the end 13 position of the outer rolling surface 2a, as shown in an enlarged view in FIG. And is set in a range of θ = 30 ° to 75 °. When the inclination angle θ is less than 30 °, the distance between the inner diameter surface of the shoulder portion 10 and the terminal end 13 of the outer rolling surface 2a is shortened, and the effect of preventing coarsening is diminished and the edge load reducing effect is lowered. On the other hand, when the inclination angle θ exceeds 75 °, the shoulder portion 10 has a small diameter, which is not preferable because of an increase in mass and interference with the cage 7.

  The surface finish of the tapered surface of the notch 11 may be a turning surface by turning before quenching or a turning surface by quenching hardened steel after quenching, but here, the outer rolling surface 2a after quenching and At the same time, it is a ground surface with a total grinding wheel. Thereby, the oxide scale adhering by the heat treatment can be surely removed, and sound and vibration deterioration due to the penetration of the oxide scale into the outer rolling surface 2a and damage from the indentation impression of the oxide scale can be prevented. Further, in the case of hardened steel cutting, the oxide scale can be removed as in the case of grinding, but since the grinding of the outer rolling surface 2a is required after that, the merits are considered in consideration of the work efficiency in which the grinding process must be performed. There are few. Furthermore, if the inner diameter surface of the shoulder portion 10 is ground by the total-type grindstone simultaneously with the outer rolling surface 2a and the notch portion 11 described above, the oxide scale can be removed more reliably.

  FIG. 4 shows a modification of FIG. This embodiment basically differs from the above-described embodiment only in the shape of the end portion 13a of the outer rolling surface 2a and the edge portion 11b of the notch portion 11 ′ of the shoulder portion 10, except for the same part. The same reference numerals are assigned and detailed description is omitted.

  A notch 11 ′ is formed in a tapered surface from the end 13a of the outer rolling surface 2a on which the rolling element 3 rolls to the shoulder 10, and the corners of the end 13a and the edge 11b of the notch 11 ′ are predetermined. It is formed in a circular arc shape having the curvature radii R1 and R2. The curvature radius R1 of the terminal end 13a is set to be larger than the curvature radius R2 of the edge portion 11b of the notch portion 11 '(R1> R2). As a result, as in the above-described embodiment, the heat raised by induction hardening is also released in the direction of the edge portion 11b, and the vicinity of the end 13a of the double-row outer raceway 2a, 2a is prevented from overheating. In addition, the edge load can be prevented from occurring when a high surface pressure is applied to the corner.

  Here, the end portion 13a of the outer rolling surface 2a and the corner portion of the edge portion 11b of the notch portion 11 ′ may be a turning surface by turning before quenching, or a turning surface by cutting hardened steel after quenching. However, here, the outer raceway surface 2a after quenching is used as a grinding surface with a total-type grindstone. Thereby, when the rolling element 3 rolls over the terminal end 13a of the outer rolling surface 2a, it is possible to prevent the rolling element 3 itself from being damaged, and an excessive load is applied by eliminating the edge portion. It is possible to prevent cracks from starting.

  FIG. 5 is an explanatory view showing the hardened layer 12 of the outer member 2 of FIG. The hardened layer 12 of the outer member 2 in this embodiment is formed so that its axial depth gradually increases in the axial direction from the contact point P position of the outer rolling surface 2a with the rolling element 3 to the shoulder 10. Yes. That is, the induction heating coil for induction hardening is formed into an appropriate shape, and the current acting on the coil is controlled. For example, the axial depths A to E of the hardened layer 12 are A <B <C <. It is set so that D <E. As a result, a sufficient hardened layer depth corresponding to the high surface pressure during turning can be ensured, and the life of the bearing can be extended.

  FIG. 6 is a longitudinal sectional view showing a second embodiment of the wheel bearing device according to the present invention. Note that this embodiment basically differs from the first embodiment (FIG. 1) described above only in the configuration of the hub wheel, and the same reference numerals are given to other parts and parts having the same function or the same function. The detailed description is omitted.

  This wheel bearing device is referred to as the third generation for driving wheels, and the inner member 15 and outer member 2, and the double row rolling elements 3, 3 accommodated between the members 15, 2 so as to roll freely. It has. The inner member 15 includes a hub ring 16 and an inner ring 5 that is press-fitted into the hub ring 16 via a predetermined scissors.

  The hub wheel 16 integrally has a wheel mounting flange 6 at an end portion on the outer side, and a hub bolt 6 a for fixing the wheel at a circumferentially equidistant position of the wheel mounting flange 6 is implanted. Further, one (outer side) inner rolling surface 4a is directly formed on the outer periphery of the hub wheel 16, and a small-diameter step portion 4b extending in the axial direction from the inner rolling surface 4a is formed. Serrations (or splines) 16a are formed. The inner ring 5 having the outer (inner side) inner rolling surface 5a formed on the outer periphery is press-fitted into the small diameter step 4b, and the end of the small diameter step 4b is plastically deformed radially outward. The inner ring 5 is fixed to the hub ring 16 in the axial direction in a state where a predetermined bearing preload is applied by the crimped portion 4c.

  The hub wheel 16 is made of medium and high carbon steel containing 0.40 to 0.80% by weight of carbon such as S53C, and has a small diameter from the seal land portion where the outer side seal 8 is in sliding contact with the outer side inner rolling surface 4a. Curing treatment is performed in the range of 58 to 64 HRC by induction hardening over the step 4b.

  The outer member 2 integrally has a vehicle body mounting flange 2b for mounting to the vehicle body (not shown) on the outer periphery, and faces the double row inner rolling surfaces 4a, 5a of the inner member 1 on the inner periphery. Double row outer rolling surfaces 2a, 2a are integrally formed. 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 after the double row outer rolling surfaces 2a and 2a are turned, surface hardening is performed by induction hardening. The hardened layer 12 is formed in the range of 58 to 64 HRC (the hardened layer 12 is indicated by cross-hatching in the figure). Thereafter, the double row outer rolling surfaces 2a, 2a are finished to a predetermined shape and surface roughness by grinding and superfinishing.

  Here, the outer member 2 has a cylindrical shoulder portion 10 formed between the double row outer rolling surfaces 2a and 2a, and annular notches 11 are formed at both ends of the shoulder portion 10. ing. The notch 11 is formed in a tapered surface having a predetermined inclination angle θ. As a result, the heat raised by induction hardening can be released in the direction of the edge portion 11a, and overheating of the vicinity of the terminal end 13 of the double row outer rolling surfaces 2a, 2a can be prevented. That is, by storing a portion in which the structure is likely to be coarse due to the influence of heat in the notch portion 11 formed of a tapered surface, the structure in the vicinity of the terminal end 13 of the outer rolling surface 2a is not coarsened. It is possible to prevent a short life due to the high surface pressure of the converted tissue. Further, when the vehicle turns μ = 0.6, the rolling element protrudes beyond the height at which it does not roll, the diameter of the rolling element is Da, and the groove curvature radius Ra of the outer rolling surface is 0.51 to 0. If 54 ≦ Da is set to h ≦ 0.45 Da, when the rolling element 3 protrudes from the end 13 of the outer rolling surface 2a and rolls, the volume receiving the load is increased, and the shoulder portion Compared to the ten edge portions 11a, the corner portion of the terminal end 13 of the outer rolling surface 2a can be prevented from becoming an extreme edge load.

  FIG. 7 is a longitudinal sectional view showing a third embodiment of the wheel bearing device according to the present invention. This embodiment basically differs from the above-described embodiment (FIGS. 1 and 6) only in the configuration of the bearing portion, and the same reference numerals are given to the same parts and parts having the same function or the same function. Detailed description will be omitted.

  This wheel bearing device is referred to as a second generation for driven wheels, and includes an outer member 17, a pair of inner rings 5, 5, and double-row rolling elements 3, 3 accommodated between the two members in a freely rotatable manner. ing.

  The outer member 17 integrally has a wheel mounting flange 6 at an end portion on the outer side, and double row outer rolling surfaces 2a and 2a are integrally formed on the inner periphery. This outer member 17 is made of medium-high carbon steel containing 0.40 to 0.80% by weight of carbon such as S53C, and after the double row outer rolling surfaces 2a and 2a are turned, surface hardening is performed by induction hardening. The hardened layer is formed in the range of 58 to 64 HRC. After induction hardening, the double row outer rolling surfaces 2a, 2a are finished to a predetermined shape and surface roughness by grinding and superfinishing.

  Here, the outer member 17 has a cylindrical shoulder portion 10 formed between the double row outer rolling surfaces 2a, 2a, and annular notches 11 are formed at both ends of the shoulder portion 10. ing. The notch 11 is formed on a tapered surface having a predetermined inclination angle θ, as in the above-described embodiment. As a result, the heat raised by induction hardening can be released in the direction of the edge portion 11a, and overheating of the vicinity of the terminal end 13 of the double row outer rolling surfaces 2a, 2a can be prevented. That is, by storing a portion in which the structure is likely to be coarse due to the influence of heat in the notch portion 11 formed of a tapered surface, the structure in the vicinity of the terminal end 13 of the outer rolling surface 2a is not coarsened. It is possible to prevent a short life due to the high surface pressure of the converted tissue.

  Further, when the vehicle turns μ = 0.6, the rolling element protrudes beyond the height at which it does not roll, the diameter of the rolling element is Da, and the groove curvature radius Ra of the outer rolling surface is 0.51 to 0. If 54 ≦ Da is set to h ≦ 0.45 Da, when the rolling element 3 protrudes from the end 13 of the outer rolling surface 2a and rolls, the volume receiving the load is increased, and the shoulder portion Compared to the ten edge portions 11a, the corner portion of the terminal end 13 of the outer rolling surface 2a can be prevented from becoming an extreme edge load.

  FIG. 8 is a longitudinal sectional view showing a fourth embodiment of the wheel bearing device according to the present invention. This embodiment basically differs from the above-described embodiment (FIGS. 1 and 6) only in the configuration of the bearing portion, and the same reference numerals are given to the same parts and parts having the same function or the same function. Detailed description will be omitted.

  This wheel bearing device is referred to as a fourth generation for driving wheels, and the inner member 18 and outer member 2, and the double row rolling elements 3, 3 accommodated between the members 18, 2 so as to roll freely. It has. The inner member 18 includes a hub wheel 19 and an outer joint member 21 that constitutes a constant velocity universal joint 20 to be described later that is fitted in the hub wheel 19.

  The hub wheel 19 integrally has a wheel mounting flange 6 at an end portion on the outer side, and has one (outer side) inner rolling surface 4a on the outer periphery and a cylindrical shape extending in the axial direction from the inner rolling surface 4a. A small diameter step 4b is formed. The hub wheel 19 is made of medium and high carbon steel containing 0.40 to 0.80% by weight of carbon such as S53C, and the inner raceway surface 4a and the base portion on the inner side of the wheel mounting flange 6 are connected to the small diameter step portion 4b. Thus, the surface hardness is set to a range of 58 to 64 HRC by induction hardening.

  Here, an uneven portion 22 that is hardened by induction hardening is formed on the inner periphery of the hub wheel 19. The concavo-convex portion 22 is formed in an iris knurl shape, a plurality of annular grooves formed independently by turning or the like, and a plurality of axial grooves formed by broaching or the like and a cross groove formed by substantially orthogonally crossing, Or it consists of the crossing groove | channel comprised by the helical groove | channel inclined mutually. Moreover, in order to ensure good biting properties, the tip of the concavo-convex portion 22 is formed in a spire shape such as a triangular shape.

  The constant velocity universal joint 20 includes an outer joint member 21, a joint inner ring 23, a cage 24, and a torque transmission ball 25. The outer joint member 21 is integrally formed with a cup-shaped mouth portion 26, a shoulder portion 27 that forms the bottom of the mouth portion 26, and a hollow shaft portion 28 that extends from the shoulder portion 27 in the axial direction. On the outer periphery of the shoulder portion 27, the other (inner side) inner rolling surface 21a facing the double row outer rolling surfaces 2a, 2a of the outer member 2 is formed. The shaft portion 28 is formed with an inrow portion 28a that is cylindrically fitted to the small-diameter step portion 4b of the hub wheel 19 via a predetermined shimiro, and a fitting portion 28b is formed at the end of the inrow portion 28a. .

  The outer joint member 21 is formed of medium-high carbon steel containing 0.40 to 0.80 wt% of carbon such as S53C, and the inner joint surface 21a, the outer periphery of the shoulder portion 27 and the inrow portion 28a of the shaft portion 28 Thus, the surface hardness is set to a range of 58 to 64 HRC by induction hardening. In addition, the fitting part 28b is left with the raw surface hardness after forging.

  Double-row rolling elements 3, 3 are accommodated between the rolling surfaces 2a, 4a and 2a, 21a of the outer member 2 and the inner member 18, and these double-row rolling elements 3, 3 is rotatably held. Further, seals 8 and 9 are attached to the opening of the annular space formed between the outer member 2 and the inner member 18, leakage of the lubricating grease sealed inside the bearing, rainwater, dust, etc. from the outside Is prevented from entering the inside of the bearing.

  Here, the shaft portion 28 of the outer joint member 21 is press-fitted into the hub wheel 19 with a predetermined squeezing force, and the shoulder portion 27 of the outer joint member 21 is abutted against the end surface of the small-diameter stepped portion 4b to apply a predetermined preload. In this state, the fitting portion 28b is expanded in diameter by pushing a diameter expanding jig such as a mandrel from the inner side toward the outer side through the inner diameter of the fitting portion 28b. The hub wheel 19 and the outer joint member 21 are integrally plastically joined by biting into 22. As a result, the device can be reduced in weight and size, and even when a large moment load is applied, loosening of the coupling portion can be prevented over a long period of time, and durability can be improved. Reference numerals 29 and 30 are end caps fitted inside the opening end of the hub wheel 19 and the shoulder 27 of the outer joint member 21. Leakage of the lubricating grease sealed inside the joint and the inside of the joint from the outside. This prevents foreign matter such as rainwater and dust from entering.

  The outer member 2 integrally has a vehicle body mounting flange 2b for mounting to the vehicle body (not shown) on the outer periphery, and faces the double row inner rolling surfaces 4a and 21a of the inner member 18 on the inner periphery. Double row outer rolling surfaces 2a, 2a are integrally formed. 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 after the double row outer rolling surfaces 2a and 2a are turned, surface hardening is performed by induction hardening. The hardened layer is formed in the range of 58 to 64 HRC. After induction hardening, the double row outer rolling surfaces 2a, 2a are finished to a predetermined shape and surface roughness by grinding and superfinishing.

  Here, the outer member 2 has a cylindrical shoulder portion 10 formed between the double row outer rolling surfaces 2a and 2a, and annular notches 11 are formed at both ends of the shoulder portion 10. ing. The notch 11 is formed in a tapered surface having a predetermined inclination angle θ. As a result, the heat raised by induction hardening can be released in the direction of the edge portion 11a, and overheating of the vicinity of the terminal end 13 of the double row outer rolling surfaces 2a, 2a can be prevented. That is, by storing a portion in which the structure is likely to be coarse due to the influence of heat in the notch portion 11 formed of a tapered surface, the structure in the vicinity of the terminal end 13 of the outer rolling surface 2a is not coarsened. It is possible to prevent a short life due to the high surface pressure of the converted tissue.

  Further, when the vehicle turns μ = 0.6, the rolling element protrudes beyond the height at which it does not roll, the diameter of the rolling element is Da, and the groove curvature radius Ra of the outer rolling surface is 0.51 to 0. If 54 ≦ Da is set to h ≦ 0.45 Da, when the rolling element 3 protrudes from the end 13 of the outer rolling surface 2a and rolls, the volume receiving the load is increased, and the shoulder portion Compared to the ten edge portions 11a, the corner portion of the terminal end 13 of the outer rolling surface 2a can be prevented from becoming an extreme edge load.

  FIG. 9 is a longitudinal sectional view showing a fifth embodiment of the wheel bearing device according to the present invention. This embodiment basically differs from the above-described embodiment (FIGS. 1 and 6) only in the configuration of the bearing portion, and the same reference numerals are given to the same parts and parts having the same function or the same function. Detailed description will be omitted.

  This wheel bearing device is referred to as a first generation, and includes an outer member 31, a pair of inner rings 5, 5 and double row rolling elements 3, 3 accommodated between the two members in a freely rotatable manner.

  The outer member 31 has a double row of outer rolling surfaces 31a and 31a formed integrally on the inner periphery. This outer member 31 is made of high carbon chrome bearing steel such as SUJ2, and after turning the outer rolling surfaces 31a, 31a of the double row, it is heated up to the core by heating with a high frequency coil or heating with a heating furnace. Curing treatment is performed in the range of 58 to 64 HRC. After quenching, the double row outer rolling surfaces 31a, 31a are finished to a predetermined shape and surface roughness by grinding and superfinishing.

  Here, the outer member 31 has a cylindrical shoulder portion 10 formed between the double-row outer rolling surfaces 31 a and 31 a, and annular notches 11 are formed at both ends of the shoulder portion 10. ing. The notch 11 is formed in a tapered surface having a predetermined inclination angle θ. As a result, when it is quenched by induction hardening, the heated heat is also released in the direction of the edge portion 11a, and the vicinity of the end 13 of the double row outer rolling surfaces 31a, 31a is overheated. Can be prevented. That is, the portion where the structure is likely to become coarse due to the influence of heat is accommodated in the notch portion 11 formed of a tapered surface, and the structure in the vicinity of the terminal end 13 of the outer rolling surface 31a is not coarsened. It is possible to prevent a short life due to the high surface pressure of the converted tissue.

  Further, when the vehicle turns μ = 0.6, the rolling element protrudes beyond the height at which it does not roll, the diameter of the rolling element is Da, and the groove curvature radius Ra of the outer rolling surface is 0.51 to 0. When 54 Da is set to h ≦ 0.45 Da, the above-mentioned partial overheating does not occur when being quenched by a heating furnace, but with the case where it is quenched by heating with a high frequency coil. Even when the rolling element 3 protrudes from the end 13 of the outer rolling surface 31a and rolls, the volume receiving the load is increased, and the end 13 of the outer rolling surface 31a is larger than the edge 11a of the shoulder 10. It is possible to prevent the corner portion from becoming an edge load and to extend the life of the bearing.

  FIG. 10 is a longitudinal sectional view showing a sixth embodiment of the wheel bearing device according to the present invention. Note that this embodiment is basically the same as the above-described embodiment (FIG. 1) except that the left and right pitch circle diameters of the double row rolling elements are different, and the same parts or parts having the same function. Are denoted by the same reference numerals, and detailed description thereof is omitted.

  This wheel bearing device is referred to as a third generation for a driven wheel, and includes an inner member 32 and an outer member 33, and a double row rolling element 3 ′ accommodated so as to roll between both members 32 and 33, 3 is provided. The inner member 32 includes a hub ring 34 and an inner ring 5 that is press-fitted into the hub ring 34 through a predetermined shimiro.

  The hub wheel 34 integrally has a wheel mounting flange 6 at an end portion on the outer side, one (outer side) inner rolling surface 34a on the outer periphery, and an axial portion extending in the axial direction from the inner rolling surface 34a. A small-diameter step portion 4 b is formed via 35.

  The hub wheel 34 is made of medium and high carbon steel containing 0.40 to 0.80% by weight of carbon such as S53C, and includes the inner rolling surface 34a and the base portion 6b on the inner side of the wheel mounting flange 6 to the small diameter step portion 4b. As a result, the surface hardness is set to a range of 58 to 64 HRC by induction hardening.

  The outer member 33 integrally has a vehicle body mounting flange 2b to be attached to a knuckle (not shown) on the outer periphery, and the outer side outer rolling facing the inner rolling surface 34a of the hub wheel 34 on the inner circumference. The surface 33a and the inner side outer rolling surface 2a facing the inner rolling surface 5a of the inner ring 5 are integrally formed. Double-row rolling elements 3 ′ and 3 are accommodated between these rolling surfaces, and are held by the cages 7 ′ and 7 so as to roll freely.

  The outer member 33 is formed of medium-high carbon steel containing 0.40 to 0.80 wt% of carbon such as S53C, and the double row outer rolling surfaces 33a and 2a have a surface hardness of 58 to 64 HRC by induction hardening. Hardened to range. Seals 8 and 9 are attached to the opening of the annular space formed between the outer member 33 and the inner member 32, and leakage of grease sealed inside the bearing and rainwater from the outside. And dust are prevented from entering the bearing.

  The outer shape of the hub wheel 34 is such that the shoulder 35 a and the inner ring 5 are brought into contact with each other via the counter part 36 from the groove bottom part of the inner rolling surface 34 a and the shaft part 35 extending in the axial direction from the counter part 36. It continues to the small diameter step 4b through 35b. A mortar-shaped recess 37 is formed at the outer end of the hub wheel 34. The depth of the recess 37 is a depth up to the vicinity of the groove bottom of the inner rolling surface 34a, and the outer side of the hub wheel 34 has a substantially uniform thickness.

  In this embodiment, the pitch circle diameter PCDo of the outer side rolling element 3 ′ is set larger than the pitch circle diameter PCDi of the inner side rolling element 3. The outer diameter do of the outer side rolling element 3 ′ is smaller than the outer diameter di of the inner side rolling element 3. The number of outer side rolling elements 3 ′ is set to be larger than the number of inner side rolling elements 3 due to the difference in pitch circle diameters PCDo and PCDi. Thus, the rigidity of the outer bearing row can be increased and the load capacity can be increased without effectively using the bearing space and increasing the outer diameter of the outer member 33. In addition, a recess 37 is formed along the outer shape at the outer end of the hub wheel 34, and the outer side of the hub wheel 34 is set to a uniform thickness, so that the device is lighter, more compact and more rigid. It is possible to solve the conflicting problem.

  In the outer member 33, the outer rolling surface 33a on the outer side is formed with a larger diameter than the outer rolling surface 2a on the inner side due to the difference in pitch circle diameters PCDo and PCDi, and the outer rolling surface 33a on the outer side is formed. From the cylindrical large-diameter shoulder 38 and the stepped portion 38a, the small-diameter shoulder 10 continues to the inner-side outer rolling surface 2a.

  Further, as shown in FIG. 11, annular notches 11 ″ at the outer rolling surfaces 33a and 2a side end portions of the large diameter shoulder 38 and the small diameter shoulder 10 of the outer member 33, respectively. The notches 11 ″ and 11 are formed on a tapered surface having a predetermined inclination angle θ. As a result, the heat raised by induction hardening is also released in the direction of the edge portion 11a, and overheating of the vicinity of the terminal ends 13 'and 13 of the double row outer rolling surfaces 33a and 2a can be prevented. . That is, a portion where the structure is likely to be coarsened due to the influence of heat is accommodated in the notches 11 ″ and 11 formed of a tapered surface, and the structure in the vicinity of the terminal ends 13 ′ and 13 of the outer rolling surfaces 33a and 2a is coarsened. By avoiding the high surface pressure of the structure, a short life due to coarsening can be prevented.

  Further, when the vehicle turns μ = 0.6, the rolling element protrudes beyond the height at which it does not roll, the diameter of the rolling element is Da, and the groove curvature radius Ra of the outer rolling surface is 0.51 to 0. As long as 54 Da is set, h ≦ 0.45 Da, the volume that receives the load even when the rolling element 3 protrudes from the terminal ends 13 ′ and 13 of the outer rolling surfaces 33 a and 2 a and rolls. In comparison with the edge portion 11a of the shoulder portion 10, it is possible to prevent the corner portions of the terminal ends 13 'and 13 of the outer rolling surfaces 33a and 2a from becoming extremely edge-loaded.

  FIG. 12 is a longitudinal sectional view showing a seventh embodiment of the wheel bearing device according to the present invention. This embodiment is basically different from the above-described embodiment (FIG. 1) only in the configuration of the left and right of the double row rolling elements, and other parts and parts having the same function or similar functions are used. The same reference numerals are assigned and detailed description is omitted.

  This wheel bearing device is referred to as a third generation for driven wheels, and includes an inner member 39 and an outer member 40, and a double row rolling element 3 ′ accommodated in a freely rolling manner between both members 39, 40. 3 is provided. The inner member 39 includes a hub ring 41 and an inner ring 5 that is press-fitted into the hub ring 41 through a predetermined shimiro.

  The hub wheel 41 integrally has a wheel mounting flange 6 at an end portion on the outer side, one (outer side) inner rolling surface 41a on the outer periphery, and an axial portion extending in an axial direction from the inner rolling surface 41a. A small-diameter step portion 4 b is formed via 35.

  The hub wheel 41 is formed of medium and high carbon steel containing 0.40 to 0.80% by weight of carbon such as S53C, and includes the inner rolling surface 41a and the base portion 6b on the inner side of the wheel mounting flange 6 to the small diameter step portion 4b. As a result, the surface hardness is set to a range of 58 to 64 HRC by induction hardening.

  The outer member 40 integrally has a vehicle body mounting flange 2 b on the outer periphery, and has an outer outer rolling surface 40 a that faces the inner rolling surface 41 a of the hub wheel 41 on the inner periphery, and an inner rolling surface of the inner ring 5. An inner side outer rolling surface 2a opposite to 5a is integrally formed. Double-row rolling elements 3 ′ and 3 are accommodated between these rolling surfaces, and are held by the cages 7 ′ and 7 so as to roll freely.

  This outer member 40 is made of medium-high carbon steel containing 0.40 to 0.80% by weight of carbon such as S53C, and the double row outer rolling surfaces 40a and 2a have a surface hardness of 58 to 64 HRC by induction hardening. Hardened to range. Seals 8 and 9 are attached to the opening of the annular space formed between the outer member 40 and the inner member 39, and leakage of grease sealed inside the bearing and rainwater from the outside. And dust are prevented from entering the bearing.

  The outer shape of the hub wheel 41 is formed through a counter portion 36 from the groove bottom portion of the inner rolling surface 41a and a shoulder portion 35b against which the inner ring 5 is abutted via a shaft-like portion 35 extending in the axial direction from the counter portion 36. It continues to the small diameter step 4b. A mortar-shaped recess 37 is formed at the outer end of the hub wheel 41.

  In this embodiment, the pitch circle diameter PCDo of the outer side rolling element 3 ′ and the pitch circle diameter PCDi of the inner side rolling element 3 are set to be the same. The outer diameter do of the outer side rolling element 3 ′ is smaller than the outer diameter di of the inner side rolling element 3. The number of outer side rolling elements 3 ′ is set to be larger than the number of inner side rolling elements 3 due to the difference in outer diameters do and di of the rolling elements 3 ′ and 3. Thereby, the rigidity of the outer bearing row can be increased, and the load capacity of the inner bearing row can be increased. Furthermore, the recess 37 is formed along the outer shape at the outer side end of the hub wheel 41, and the outer side of the hub wheel 41 is set to have a uniform thickness, so that the device is lighter, more compact and more rigid. It is possible to solve the conflicting problem.

  Further, as shown in FIG. 13, annular notches 11 ″ and 11 are formed at both ends of the shoulder 10 of the outer member 40. The notches 11 ″ and 11 are formed from a predetermined inclination angle θ. It is formed on the tapered surface. As a result, the heat raised by induction hardening is also released in the direction of the edge portion 11a, and overheating of the vicinity of the terminal ends 13 'and 13 of the double row outer rolling surfaces 40a and 2a can be prevented. . That is, the portion where the structure is likely to become coarse due to the influence of heat is accommodated in the notches 11 ″ and 11 having a tapered surface, and the structure in the vicinity of the terminal ends 13 ′ and 13 of the outer rolling surfaces 40a and 2a is not coarse. By doing so, the short life by the high surface pressure of the coarse structure can be prevented.

  Further, when the vehicle turns μ = 0.6, the rolling element protrudes beyond the height at which it does not roll, the diameter of the rolling element is Da, and the groove curvature radius Ra of the outer rolling surface is 0.51 to 0. As long as 54 Da is set, h ≦ 0.45 Da, the volume that receives the load even when the rolling element 3 protrudes and rolls from the terminal ends 13 ′, 13 of the outer rolling surfaces 40 a, 2 a In comparison with the edge portion 11a of the shoulder portion 10, it is possible to prevent the corner portions of the terminal ends 13 'and 13 of the outer rolling surfaces 40a and 2a from being extremely edge-loaded.

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

  The wheel bearing device according to the present invention can be applied to a wheel bearing device having a first generation to a fourth generation structure including an outer member in which double row outer rolling surfaces are integrally formed on the inner periphery.

1, 15, 18, 32, 39 Inner members 2, 17, 31, 33, 40 Outer members 2a, 31a, 33a, 40a Outer rolling surface 2b Car body mounting flange 3, 3 'Rolling bodies 4, 16, 19 , 34, 41 Hub wheel 4a, 5a, 21a, 34a, 41a Inner rolling surface 4b Small-diameter stepped portion 4c Clamping portion 5 Inner ring 6 Wheel mounting flange 6a Hub bolt 6b Base portion 7, 7 'on the inner side of the wheel mounting flange 8, 9 Seal 10, 27, 35b, 38 Shoulder 11, 11 ', 11 "Notch 11a, 11b Edge 12 Hardened layer 13, 13', 13a End of outer rolling surface 14 Tangent of outer rolling surface 16a Serration 20 Constant velocity universal joint 21 Outer joint member 22 Uneven portion 23 Joint inner ring 24 Cage 25 Torque transmission ball 26 Mouse portion 28 Shaft portion 28a Inrow portion 28b Fitting portions 29, 30 Decap 35 Axial part 35a, 38a Step part 36 Counter part 37 Recess 51 Outer member 51a, 51b Outer rolling surface 52 Shoulder part 53 Hardened layer 54 Notch part 55 Edge parts A to E Axial depth of hardened layer Di The outer diameter of the inner side rolling element do The outer diameter Da of the outer side rolling element Da The diameter of the rolling element h The height from the groove bottom at the inner diameter side of the outer rolling surface H The groove bottom of the inner diameter surface of the shoulder Height from PCDi Pitch circle diameter of the inner side rolling element PCDo Pitch circle diameter of the outer side rolling element R1 Curvature radius of the end of the outer rolling surface R2 Curvature radius of the corner of the notch edge Ra Radius of curvature of outer raceway α Angle formed by tangent of outer raceway and inner diameter of shoulder θ Angle of notch

Claims (10)

An outer member in which a double row outer rolling surface is integrally formed on the inner periphery;
An inner member in which a double row inner rolling surface facing the outer row rolling surface of the double row is formed 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 cylindrical shoulder is formed between the outer rolling surfaces of the double row of the outer member, and a tapered surface is formed from the end of the outer rolling surface where the rolling element rolls to the shoulder. The end of the outer rolling surface and the corner of the edge of the tapered surface are formed in an arc shape having predetermined curvature radii R1 and R2, and the curvature radius R1 on the end side is the radius of curvature of the edge of the tapered surface. It is set larger than R2 (R1> R2),
The inclination angle of the tapered surface is smaller than the angle formed by the tangent line of the outer rolling surface at the terminal position of the outer rolling surface and the inner diameter surface of the shoulder, and is set in a range of 30 ° to 75 °.
A wheel bearing device, wherein a predetermined hardened layer is formed on the outer rolling surfaces of the double row to form a ground surface .   2. The wheel bearing device according to claim 1, wherein the austenite grain size within 1 mm from the surface of the hardened layer at the terminal portion of the outer rolling surface is set smaller than the austenite grain size of the edge portion of the tapered surface.   The height h from the groove bottom on the inner diameter side of the outer rolling surface is not less than the height at which the rolling element protrudes and does not roll when the vehicle turns μ = 0.6 to which the wheel bearing device is applied. And when the diameter of the rolling element is Da and the groove curvature radius Ra of the outer rolling surface is 0.51 to 0.54 Da, h ≦ 0.45 Da is set. Wheel bearing device.   The wheel according to claim 1, wherein the height H of the inner diameter surface of the shoulder portion from the groove bottom of the outer rolling surface is set to H≤0.5 Da, where Da is the diameter of the rolling element. Bearing device. A bearing device for a wheel according to claim 1 or 2 are said tapered MengaKen Kezumen. A bearing device for a wheel according to claim 1 or 4 inner surface of the shoulder portion that is the ground surface.   The wheel according to claim 1, wherein an axial depth of a hardened layer of the outer member is formed so as to gradually increase in an axial direction from a contact point position with the rolling element of the outer rolling surface to the shoulder. Bearing device.   The outer member is formed of medium-high carbon steel containing carbon of 0.40 to 0.80% by weight, and at least the surface hardness of the outer raceway of the double row is set in a range of 58 to 64 HRC. The wheel bearing device according to 1 or 7. The outer member is integrally provided with a vehicle body mounting flange for mounting a vehicle body on the outer periphery, and the inner member is integrally provided with a wheel mounting flange for mounting a wheel on one end, and the double row is disposed on the outer periphery. A hub ring formed with an inner rolling surface facing one of the outer rolling surfaces, a small diameter step portion extending in an axial direction from the inner rolling surface, and an outer periphery fixed to the small diameter step portion of the hub ring The wheel bearing device according to claim 1, further comprising an inner ring formed with an inner rolling surface facing the other of the double row outer rolling surfaces.   The outer member is integrally provided with a vehicle body mounting flange for mounting a vehicle body on the outer periphery, and the inner member is integrally provided with a wheel mounting flange for mounting a wheel on one end, and the double row is disposed on the outer periphery. The outer raceway is fitted to the inner raceway surface facing one of the outer raceway surfaces, a hub wheel formed with a small-diameter step portion extending in the axial direction from the inner raceway surface, and a small-diameter step portion of the hub wheel. Are formed of an outer joint member of a constant velocity universal joint formed with an inner rolling surface facing the other of the double row outer rolling surfaces, and the outer joint member and the hub ring are integrally plastically coupled. The wheel bearing device according to claim 1.

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