JP4021293B2 - Wheel bearing device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a wheel bearing device for supporting wheels of a vehicle such as an automobile.
[0002]
[Prior art]
Wheel bearing devices are roughly classified into driven wheels and driving wheels. Among these, for example, a wheel bearing device for a drive wheel is composed of a hub wheel and a double row bearing, and there is also a unit in which these and a constant velocity universal joint are unitized.
[0003]
One of the wheel bearing devices for driving wheels is one in which one of the double row inner races of the bearing is formed on the outer periphery of the hub wheel and the other is formed on the outer periphery of the outer joint member of the constant velocity universal joint. In this type of bearing device, it is necessary to connect the hub wheel and the constant velocity universal joint in order to position the double-row inner race and to maintain the preload applied in the bearing. In recent years, from the viewpoint of effective utilization of the axial space and improvement of rigidity at the plastic deformation part, the stem part of the outer joint member is plastically deformed in the diameter expansion direction, and the uneven part of the inner periphery of the hub wheel is bitten by this. (Hereinafter, referred to as “expansion caulking”) has been proposed (for example, Japanese Patent Laid-Open No. 2001-18605).
[0004]
In this type of wheel bearing device, the outer joint member and the hub wheel are both forged. After forging, the outer joint member is ground on the outer periphery of the stem portion and the track groove on the inner periphery of the mouse portion. In addition, the hub ring is ground on the inner periphery and inner race after forging, and further, an uneven portion is formed on the inner periphery by broaching or the like. Therefore, in the finished product, the ground surface remains on the outer periphery of the plastic deformation portion and the surface of the uneven portion (particularly the surface of the convex portion).
[0005]
[Patent Document 1]
Japanese Patent Laid-Open No. 2001-18605
[Problems to be solved by the invention]
In the above-described enlarged diameter caulking type wheel bearing device, fretting may occur between the plastic deformation portion of the outer joint member and the uneven portion of the hub wheel after plastic deformation in the expansion direction. As fretting progresses, the preload of the bearing is reduced and the axial force is reduced, so that the product function may be remarkably deteriorated. Therefore, it is desirable to take measures to avoid such problems.
[0007]
In general, countermeasures against fretting in general machine parts are performed in such a manner that a friction-reducing material such as a lubricant is interposed between two opposing surfaces to reduce the friction coefficient between the two surfaces. Following this measure, even in the wheel bearing device described above, the outer peripheral surface of the plastically deformed portion is subjected to a bond process, and then subjected to an endurance test by performing diameter expansion caulking, but rather the durability life of the bearing device is reduced. It became clear.
[0008]
In view of the above phenomenon, an object of the present invention is to provide a wheel bearing device that can reliably suppress fretting between a plastic deformation portion of an outer joint member and an uneven portion of a hub ring.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, a wheel bearing device according to the present invention is fitted to an outer member having a double row outer race formed on the inner periphery, a hub wheel having a wheel mounting flange, and an inner periphery or outer periphery of the hub wheel. It has a mating member, an inner member with a double-row inner race formed on the outer periphery, and a double-row rolling element interposed between the outer race and the inner race. Among the members, in the wheel bearing device in which the inner diameter side member is provided with a plastic deformation portion that is plastically deformed in the diameter increasing direction, and the outer diameter side member is provided with an uneven portion that bites into the expanded diameter plastic deformation portion, Roughness to increase the friction coefficient between two surfaces on the outer peripheral surface of the plastic deformation portion and the surface of the concavo-convex portion with metal contact without interposing low friction inclusions between both surfaces and at least one surface of both surfaces. subjected to roughening treatment, of prior plastic deformation of the plastic deformation portion 'The ratio of the inner diameter .phi.D1 after the plastic deformation Δ (Δ = φd1 / φd1' dimensions .phi.D1) of 1.05 or more is obtained by 1.20 or less.
Further, the outer peripheral surface of the plastic deformation portion and the surface of the concavo-convex portion are brought into metal contact without interposing low-friction inclusions between both surfaces , and at least one surface of both surfaces is forged skin, The ratio Δ (Δ = φd1 / φd1 ′) between the inner diameter dimension φd1 ′ before plastic deformation and the inner diameter dimension φd1 after plastic deformation is set to 1.05 or more .
[0010]
In the wheel bearing device described above, since the concavo-convex portion bites into the plastic deformation portion after plastic deformation, originally no slip occurs between the hub wheel and the outer joint member. However, since it is difficult to fill all of the concave and convex portions of the plastic deformed portion with plastic flow, a minute relative slip occurs between the hub wheel and the outer joint member due to rotational torque, etc. Wear (fretting wear) may occur due to minute slip. In the present invention, the friction coefficient between two surfaces is increased by roughening, and thereby minute slip generated between both surfaces is regulated.
[0011]
Specifically, the surface roughening is performed such that the surface roughness of the roughened portion is Ra 1.6 or more (preferably Ra 3.2 or more) in terms of the centerline average roughness specified by JIS. In the conventional product, since the outer peripheral surface of the plastic deformation portion and the surface of the uneven portion are ground surfaces, the surface roughness was about Ra 0.2 to 0.63, but the present invention is more intentional than this. It is rough. As a result of experiments by the present inventors, it has been clarified that when Ra is smaller than 1.6, a remarkable fretting prevention effect cannot be expected.
[0012]
On the other hand, if the surface roughness of the roughened portion exceeds Ra12.5, a predetermined dimensional tolerance cannot be obtained. Therefore, the surface roughness is Ra12.5 or less, more preferably Ra6.3 or less. Is desirable.
[0013]
In order to enhance the effect of preventing fretting due to roughening, it is desirable that the outer peripheral surface of the plastic deformation portion and the surface of the concavo-convex portion are brought into metal contact without interposing low friction inclusions.
[0014]
The “low-friction inclusion” as used herein refers to a case where these are in metal contact between the outer peripheral surface of the plastic deformation portion and the surface of the concavo-convex portion (including cases where one or both are hardened layers by heat treatment). Inclusions that can provide a lower coefficient of friction, such as lubricating oil or grease oil film, solid lubricating film, bonder film or Parker film.
[0015]
As a specific configuration of the wheel bearing device, as described above, the fitting member may be an outer joint member of a constant velocity universal joint. In this case, either the hub wheel or the outer joint member becomes a member on the inner diameter side, and is subjected to plastic deformation processing in the diameter increasing direction. The other is a member on the outer diameter side. In either case, double row inner races can be formed on the outer circumferences of the hub wheel and the outer joint member (see FIGS. 1 and 5).
[0016]
As another specific configuration, for example, it is conceivable that the fitting member is an inner ring fitted to the hub ring. In this case, the double-row inner race can be formed on each outer periphery of the hub wheel and the inner ring (see FIG. 6), or can be formed on each outer periphery of two inner rings fitted on the outer periphery of the hub ring ( (See FIG. 7).
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to FIGS.
[0018]
FIG. 1 shows an example of a wheel bearing device for a drive wheel to which the present invention is applied. This wheel bearing device is configured by unitizing the hub wheel 10, the bearing 20, and the constant velocity universal joint 40. In the following description, the side closer to the outside of the vehicle when assembled to the vehicle is referred to as the outboard side (the left side of the drawing in each figure), and the side closer to the center of the vehicle is referred to as the inboard side (in each figure). Right side of the drawing).
[0019]
The hub wheel 10 is formed in a hollow shape having an axial through hole in the shaft center portion. A wheel mounting flange 14 for mounting a wheel (not shown) is formed at an end portion on the outboard side of the hub wheel 10, and a hub bolt for fixing a wheel disk at circumferentially equidistant positions of the flange 14. 15 has been implanted. An inner race 27 on the outboard side is formed on the outer peripheral surface on the inboard side of the flange 14 of the hub wheel 10.
[0020]
The constant velocity universal joint 40 transmits torque from the drive shaft to the outer joint member 41 via the inner joint member 42 and the torque transmission ball 43. A plurality of track grooves 41 a are formed in the inner peripheral portion of the outer joint member 41. A plurality of ball tracks are formed in cooperation with the track grooves 41 a and a plurality of track grooves 42 a provided on the outer peripheral portion of the inner joint member 42, and a torque transmission ball 43 is disposed on each ball track. Each torque transmission ball 43 is held in the same plane by a cage 44 (see FIG. 5).
[0021]
The outer joint member 41 is a fitting member fitted to the inner periphery of the hub wheel 10. The outer joint member 41 includes a stem portion 45 and a mouth portion 46 that are integrally formed, and is fitted to the inner periphery of the hub wheel 10 by the stem portion 45. The shoulder surface 47 of the mouse portion 46 abuts against the end surface on the inboard side of the hub wheel 10, whereby the hub wheel 10 and the outer joint member 41 are positioned in the axial direction, and the dimension between the inner races 27 and 28. Is defined. An inner lace 28 on the inboard side is formed on the outer peripheral surface of the mouse portion 46 near the shoulder surface 47. The outer joint member 41 is formed hollow by providing the stem portion 45 with an axial through hole 48 communicating with the bottom of the bowl-shaped mouth portion 46. The stem portion 45 is formed with a plastic deformation portion 34 that is plastically deformed to the outer diameter side at the time of expansion caulking described later at the shaft end on the outboard side.
[0022]
As a material of the outer joint member 41, carbon steel for mechanical structure (specified in JIS) having carbon amount of 0.30 to 0.61 can be widely used, including S40C and S53C. In addition, it contains 0.5 to 0.7% by weight, 0.6 to 1.2% Si, 0.6 to 1.0% Mn, and the balance of Fe and inevitable impurities. Steel can also be used.
[0023]
The outer joint member 41 is partially heat treated after the forging of the material. As shown in FIG. 1 with hatching, the portion hardened by the heat treatment is a region extending from the shoulder surface 47 to the sliding contact surface (seal land) with the seal lip of the seal 26 through the inner race 28 on the inboard side. And an area of the track groove 41a on the inner periphery of the mouse portion 46 where the torque transmitting ball rolls, and both are hardened until reaching HRc58 or more. As the heat treatment, induction hardening is suitable, in which local heating can be performed, the depth of the hardened layer can be freely selected, and the performance of the base material can be maintained with little influence on the heat other than the hardened layer.
[0024]
In other parts, in particular, in the stem portion 45, the plastic deformation portion 34 is not subjected to heat treatment even after forging. Of these unheat-treated parts, the hardness of the plastically deformed part 34 is preferably as low as possible in view of the workability at the time of diameter expansion caulking, but if it is too low, the fatigue durability is reduced. Therefore, it is preferable that the plastic deformation portion 34 has a hardness of HRc 13 to 28, preferably HRc 18 to 25.
[0025]
The bearing 20 includes an outer member 21 and double row rolling elements 22. The outer member 21 includes a flange 23 for attachment to a vehicle body (not shown), and a double-row outer race 24 on which the double-row rolling elements 22 roll is formed on the inner peripheral surface. Double row rolling elements 22 are incorporated between the inner race 27 of the hub wheel 10, the inner race 28 of the outer joint member 41, and the double row outer race 24 of the outer member 21. Here, the case of a double row angular contact ball bearing using a ball as the rolling element 22 is illustrated. However, in the case of a wheel bearing device for automobiles which is heavy in weight, a double row tapered roller using a tapered roller as the rolling element is shown. A bearing may be employed. Seals 25 and 26 are attached to openings at both ends of the outer member 21 to prevent leakage of grease filled in the bearing and intrusion of water and foreign matters from the outside.
[0026]
An uneven portion 31 is formed in a portion of the inner periphery of the hub wheel 10 facing the outer periphery of the plastic deformation portion 34 of the outer joint member 41. On the inboard side of the concavo-convex portion 31, a fitting surface 16 is formed which is closely fitted to the cylindrical outer peripheral surface of the stem portion 45, and the bending moment loaded on the wheel bearing device is supported by the fitting of both. It has a structure.
[0027]
The concavo-convex shape of the concavo-convex portion 31 is arbitrary, and is formed into, for example, a screw shape or a serration (including spline) shape by a broaching process after forging, or an iris knurl shape in which a plurality of parallel grooves are crossed. The The concavo-convex portion 31 thus formed is cured to HRc 58 or higher by heat treatment.
[0028]
As shown by hatching in FIG. 1, the hardened layer by heat treatment is not only the region of the uneven portion 31 on the inner periphery of the hub wheel 10 but also on the inboard side from the seal land of the seal 25 on the outer periphery of the hub wheel 10 through the inner race 27. It is also formed in a region that reaches the end face of. These heat treatments are desirably performed by induction hardening for the same reason as described above. It should be noted that by making both the hardened layers discontinuous as shown in the figure, it is possible to make the hub wheel 10 hard to be cracked.
[0029]
The hub wheel 10 as the member on the inner diameter side and the outer joint member 41 as the fitting member are integrally plastically coupled by so-called diameter expansion caulking. That is, in a state where the stem portion 45 of the outer joint member 41 is fitted to the inner periphery of the hub wheel 10, the plastic deformation portion 34 of the stem portion 45 is plastically deformed from the inner diameter side to the outer diameter side, and the outer periphery of the plastic deformation portion 34 is The hub wheel 10 and the outer joint member 41 are plastically coupled by biting into the concavo-convex portion 31. Thereby, the dimension between the inner races 27 and 28 is defined, and a predetermined preload is applied to the inside of the bearing 20. The plastically coupled hub wheel 10 and the outer joint member 41 form an inner member 29 having double rows of inner races 27 and 28 on the outer periphery.
[0030]
At the time of caulking, as described above, the uneven portion 31 has a high hardness so that it is not easily crushed, and the plastic deformation portion 34 on the expanded diameter side has a lower hardness than the uneven portion 31 and is rich in ductility. Even if it is large, caulking cracks are unlikely to occur in the stem portion 45. Therefore, the uneven portion 31 can be deeply digged into the plastic deformation portion 34, and thereby a high bonding strength is ensured between the hub wheel 10 and the outer joint member 41.
[0031]
For example, as shown in FIG. 2, the crimping can be performed by inserting a crimping jig (punch) 60 into the through hole 48 in the inner periphery of the stem portion 45 of the outer joint member 41. The caulking jig 60 includes a small-diameter cylindrical portion 61, a tapered portion 62, and a large-diameter cylindrical portion 63 in order from the distal end side (insertion side to the stem portion 45). The outer diameter dimension of the small-diameter cylindrical portion 61 is It is smaller than the inner diameter dimension of the plastic deformation part 34 before caulking, and the outer diameter dimension of the large diameter cylindrical part 63 is larger than the inner diameter dimension.
[0032]
At the time of caulking, the wheel bearing device is set on the cradle 64 with the outer joint member 41 inserted into the inner periphery of the hub wheel 10. At this time, the end surface on the outboard side of the wheel mounting flange 14 is supported by the end surface of the cradle 64. The hub bolt 15 is accommodated in a bolt hole 65 provided in the cradle 64.
[0033]
In this state, the caulking jig 60 is pushed into the through hole 48 of the outer joint member 41 from the inboard side. As a result, the plastic deformation portion 34 of the stem portion 45 is expanded by the tapered surface 62 of the caulking jig 60 and further by the large-diameter cylindrical portion 63 and is plastically deformed in the diameter-expanding direction so that the outer peripheral surface is the inner periphery of the hub wheel 10. It bites into the uneven part 31.
[0034]
At this time, as the caulking jig 60 is pushed, the outer joint member 41 receives a pushing force toward the outboard side. On the other hand, since the hub wheel 10 supported by the cradle 64 opposes this pushing force, the axial contact portion between the hub wheel 10 and the outer joint member 41 (the shoulder surface 47 of the outer joint member 41 and the hub wheel 10). Compressive strain occurs at the contact portion with the end face on the inboard side. This makes it possible to apply a preload to the bearing 20 with the axial bearing gap being negative, and to complete the preload setting simultaneously with the completion of the caulking connection. A similar effect can be obtained by inserting the caulking jig 60 in a direction in which compressive strain is generated at the abutting portion (axial abutting portion) between the two members to be caulked and joined.
[0035]
When the diameter of the plastic deformation portion 34 is increased, if the amount of expansion is equal to or less than a certain amount, the amount of biting of the plastic deformation portion 34 with respect to the concavo-convex portion 31 is insufficient, and therefore the inner diameter dimension φd1 of the plastic deformation portion 34 before plastic deformation. The ratio Δ (Δ = φd1 / φd1 ′) between “and the inner diameter dimension φd1 after plastic deformation is preferably 1.05 or more (φd1 and φd1 ′ are not shown). On the other hand, if the amount of diameter expansion is equal to or greater than a certain amount, the extension of the material may be excessive, which may cause problems such as caulking cracks. Therefore, the upper limit value of the ratio Δ is (the plastic deformation portion 34 It is desirable to set it in the range of 1.14 to 1.20 (depending on the amount of carbon contained in the material).
[0036]
In the wheel bearing device according to the present invention, the outer peripheral surface of the plastic deformation portion 34 of the outer joint member 41 is roughened as compared with the conventional product. Specific means for roughening include, for example, a method of subjecting the surface after forging / grinding to chemical / physical treatment, a method of subjecting the surface after forging / grinding to mechanical treatment such as sandblasting, or after forging A method in which the grinding process is omitted and the outer peripheral surface is used with the forged skin (including those that have been heat-treated thereafter) may be considered. If grinding is omitted, the machining cost can be reduced accordingly.
[0037]
This roughening is performed so that the surface roughness of the outer periphery of the plastic deformation portion 34 is in the range of Ra 1.6 to 12.5, and more preferably in the range of Ra 3.2 to 6.3. The surface roughness of the outer periphery of the plastic deformation portion 34 is measured before the outer joint member 41 and the hub wheel 10 are joined by caulking, and even after the caulking connection, as shown in FIG. It can also be measured at the outer peripheral surface 34a of the plastically deformed portion 34 where the portion 31a does not bite. On the surface of the plastic deformation portion 34, the surface roughness can be easily measured because the area of the portion where the uneven portion 31 does not bite is large.
[0038]
By setting the surface roughness as described above, the coefficient of friction between the surface of the concavo-convex portion 31 and the outer periphery of the plastic deformation portion 34 before caulking is compared with that of a conventional product (μ = 0.08). It can be increased (for example, about 0.18). FIG. 4 shows the results of a durability life comparison test on wheel bearing devices having the friction coefficients of 0.08 (comparative product) and 0.18 (product of the present invention). As is apparent from the drawing, the product of the present invention has a durability life of about 1.4 times that of the conventional product, and the fretting suppression effect of the present invention has been demonstrated. In order to obtain such an effect, it is desirable to set the friction coefficient to 0.1 or more.
[0039]
From the viewpoint of increasing the friction coefficient, it is not preferable to interpose a low-friction inclusion such as an oil film between the outer peripheral surface of the plastic deformation portion 34 and the surface of the uneven portion 31. Therefore, it is desirable to make metal contact between both surfaces without the presence of these inclusions.
[0040]
The roughening can be performed on the surface of the uneven portion 31 as well as on the outer periphery of the plastic deformation portion 34 as described above. In this case, the roughening may be performed before the formation of the concavo-convex portion 31, that is, at the stage where the formation region of the concavo-convex portion is still a smooth surface, or after the formation of the concavo-convex portion 31 if possible. Further, it is sufficient that the roughening is performed at least in the vicinity of the convex portion 31a (see FIG. 3) that contacts the plastic deformation portion 34 after the caulking connection, and it is necessary that the roughening is necessarily performed on the entire surface of the uneven portion 31. There is no. Of course, both the outer periphery of the plastic deformation portion 34 and the uneven portion 31 may be roughened.
[0041]
In FIG. 1, the hub wheel 10 is arranged on the outer diameter side in the caulking portion, but conversely, the present invention is similarly applied to a wheel bearing device in which the outer joint member 41 is arranged on the outer diameter side. (See FIG. 5). In this case, the hub wheel 10 becomes a member on the inner diameter side, the plastic deformation portion 34 is formed on the inboard side, and the outer joint member 41 becomes a fitting member fitted on the outer periphery thereof. Further, the concavo-convex portion 31 is formed in the inner periphery of the outer joint member 41 and in a region facing the plastic deformation portion 34 of the hub wheel.
[0042]
Hereinafter, other embodiments of the wheel bearing device will be described with reference to FIGS. 6 and 7. In both figures, members having the same functions as those shown in FIG. 1 are given the same reference numerals, and redundant description is omitted.
[0043]
FIG. 6 shows an embodiment in which the inner member 29 is formed by the hub wheel 10 and the inner ring 50 fitted to the outer periphery of the hub wheel 10. Of the inner races 27, 28 of the inner member 29, the inner race 27 on the outboard side is formed on the outer periphery of the hub wheel 10, and the inner race 28 on the inboard side is formed on the outer periphery of the inner ring 50.
[0044]
In this embodiment, the inner ring 50 is press-fitted into the outer periphery of the small-diameter cylindrical portion 19 formed at the inboard side end of the hub wheel 10. The outer joint member 41 is fitted to the inner periphery of the hub wheel 10, is connected to the hub wheel 10 via a torque transmission means 37 such as a spline, and is prevented from coming off from the hub wheel 10 by a retaining ring 38. . The end surface on the inboard side of the inner ring 50 is in contact with the shoulder surface 47 of the outer joint member 41, and the end surface on the outboard side is in contact with the shoulder surface 18 of the hub wheel 10.
[0045]
In this embodiment, the plastic deformation portion 34 is formed in the small-diameter cylindrical portion 19 of the hub wheel 10, and the uneven portion 31 is formed on the inner periphery of the inner ring 50 (the formation region of the uneven portion 31 is indicated by x). By making the plastic deformation portion 34 of the hub wheel 10 an unheat-treated portion and plastically deforming it in the diameter increasing direction, the outer periphery of the plastic deformation portion 34 bites into the concavo-convex portion 31 of the inner ring 50 so that the hub wheel 10 and the inner ring 50 are Be joined plastically. In this case, the hub wheel 10 is a member on the inner diameter side, and the inner ring 50 is a fitting member fitted to the outer periphery of the hub wheel 10.
[0046]
FIG. 7 shows an embodiment in which the inner member 29 is formed by the hub wheel 10 and the first inner ring 51 and the second inner ring 52 fitted to the outer periphery of the hub wheel 10. The inner races 27 and 28 of the inner member 29 are formed on the outer circumferences of the inner rings 51 and 52, respectively. An outer joint member (not shown) is fitted to the inner periphery of the hub wheel 10 and is coupled to the hub wheel 10 so that torque can be transmitted.
[0047]
An axially extending portion 53 is formed at the inboard side end portion of the first inner ring 51 on the inboard side, and an uneven portion 31 is formed on the inner periphery thereof. The plastic deformation portion 34 at the end of the inboard side of the hub wheel 10 is used as an unheat-treated portion, and this portion is plastically deformed in the diameter-expanding direction so as to bite into the uneven portion 31, whereby the hub wheel 10 and the inner ring 51 are plasticized. Combined with In this case, the hub wheel 10 is a member on the inner diameter side, and the inner rings 51 and 52 are fitting members fitted to the outer periphery of the hub wheel 10.
[0048]
The present invention can be similarly applied to any of the embodiments shown in FIGS.
[0049]
6 and 7 exemplify the wheel bearing device for the drive wheel in which the hub wheel 10, the bearing 20, and the outer joint member are unitized as the wheel bearing device, the hub joint does not include the outer joint member. The present invention can be similarly applied to a wheel bearing device for a driven wheel in which only the wheel 10 and the bearing 20 are unitized.
[0050]
【The invention's effect】
According to the present invention, since at least one of the outer peripheral surface of the plastic deformation portion and the surface of the uneven portion is roughened from the conventional product, fretting occurring between these two surfaces can be suppressed. . Therefore, the durability life of the wheel bearing device can be improved.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an embodiment of a wheel bearing device according to the present invention.
FIG. 2 is a sectional view showing a diameter expansion caulking process of the wheel bearing device.
FIG. 3 is an enlarged view of an axial cross section of a caulking joint.
FIG. 4 is a diagram showing the results of a durability life comparison test between a conventional product and a product of the present invention.
FIG. 5 is a sectional view showing another embodiment of the wheel bearing device according to the present invention.
FIG. 6 is a sectional view showing another embodiment of the wheel bearing device according to the present invention.
FIG. 7 is a sectional view showing another embodiment of the wheel bearing device according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Hub wheel 14 Wheel mounting flange 20 Bearing 21 Outer member 22 Rolling element 24 Outer race 27 Inner race (outboard side)
28 Inner race (inboard side)
29 Inner member 31 Uneven portion 34 Plastic deformation portion 40 Constant velocity universal joint 41 Outer joint member 50 Inner ring 51 First inner ring 52 Second inner ring

Claims (7)

An outer member having a double row outer race formed on the inner periphery;
A hub wheel having a wheel mounting flange, and an inner member having a fitting member fitted to the inner periphery or outer periphery of the hub wheel, and a double row inner race formed on the outer periphery;
A double row rolling element interposed between the outer race and the inner race, and a plastic deformation portion that is plastically deformed in the diameter-expanding direction is provided on a member on the inner diameter side of the hub wheel and the fitting member. In the wheel bearing device in which the uneven portion that bites into the expanded plastic deformation portion is provided on the outer diameter side member,
Roughness to increase the friction coefficient between two surfaces on the outer peripheral surface of the plastic deformation portion and the surface of the concavo-convex portion with metal contact without interposing low friction inclusions between both surfaces and at least one surface of both surfaces. Surface treatment was performed, and the ratio Δ (Δ = φd1 / φd1 ′) between the inner diameter dimension φd1 ′ before plastic deformation of the plastic deformation portion and the inner diameter dimension φd1 after plastic deformation was set to 1.05 or more and 1.20 or less. A wheel bearing device. An outer member having a double row outer race formed on the inner periphery;
A hub wheel having a wheel mounting flange, and an inner member having a fitting member fitted to the inner periphery or outer periphery of the hub wheel, and a double row inner race formed on the outer periphery;
A double row rolling element interposed between the outer race and the inner race, and a plastic deformation portion that is plastically deformed in the diameter-expanding direction is provided on a member on the inner diameter side of the hub wheel and the fitting member. In the wheel bearing device in which the uneven portion that bites into the expanded plastic deformation portion is provided on the outer diameter side member,
The outer peripheral surface of the plastic deformation part and the surface of the concavo-convex part are brought into metal contact without interposing low-friction inclusions between both surfaces , and at least one surface of both surfaces is forged skin, and the plastic deformation of the plastic deformation part A wheel bearing device characterized in that a ratio Δ (Δ = φd1 / φd1 ′) between a previous inner diameter dimension φd1 ′ and a plastic inner diameter dimension φd1 is 1.05 or more and 1.20 or less . The wheel bearing device according to claim 1 or 2, wherein the surface roughness of the one surface is Ra 1.6 or more and Ra 12.5 or less .   The wheel bearing device according to any one of claims 1 to 3, wherein the fitting member is an outer joint member of a constant velocity universal joint, and a double row inner race is formed on each outer periphery of the hub wheel and the outer joint member.   The wheel bearing device according to any one of claims 1 to 3, wherein the fitting member is an inner ring fitted to the outer periphery of the hub wheel.   The wheel bearing device according to claim 5, wherein the double row inner race is formed on each outer periphery of the hub wheel and the inner ring.   The wheel bearing device according to claim 5, wherein the double row inner race is formed on each outer periphery of two inner rings fitted on the outer periphery of the hub wheel.

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