JP4071965B2 - Drive wheel bearing device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a drive wheel bearing device that supports a drive wheel of an automobile or the like, and more particularly to a drive wheel bearing device in which a hub wheel, a constant velocity universal joint, and a double row rolling bearing are unitized.
[0002]
[Prior art]
Driving wheels of automobiles such as rear wheels of FR vehicles, front wheels of FF vehicles, or all wheels of 4WD vehicles are supported on a suspension device by a bearing device for driving wheels. In recent years, bearing devices for drive wheels have a tendency to unitize a hub wheel, a constant velocity universal joint, and a bearing portion in order to reduce weight and size.
[0003]
FIG. 4 is a longitudinal sectional view showing a conventional drive wheel bearing device, in which a hub wheel 50, a bearing portion 60, and a constant velocity universal joint 70 are unitized. The hub wheel 50 integrally has a wheel mounting flange 51 for mounting a wheel (not shown), and a hub bolt 52 for fixing the wheel is implanted at a circumferentially equidistant position of the wheel mounting flange 51. Yes.
[0004]
The bearing portion 60 includes an outer member 61, an inner member 62, and double-row rolling elements 63, 63. The outer member 61 is integrally provided with a vehicle body mounting flange 64 for mounting to a vehicle body (not shown) on the outer periphery. And the double-row rolling surfaces 61a and 61a are formed on the inner periphery. On the other hand, the inner member 62 forms double-row rolling surfaces 50a and 71a facing the rolling surfaces 61a and 61a of the outer member 61 described above. One rolling surface 50 a is integrally formed on the outer periphery of the hub wheel 50, and the other rolling surface 71 a is integrally formed on the outer periphery of the outer joint member 71 of the constant velocity universal joint 70. Double-row rolling elements 63 and 63 are accommodated between the rolling surfaces 61a and 50a and 61a and 71a, respectively, and are held by rollers 65 and 65 so as to be freely rollable. In this case, the inner member 62 refers to the hub wheel 50 and the outer joint member 71. Seals 66 and 67 are attached to the end portion of the bearing portion 60 to prevent leakage of lubricating grease sealed inside the bearing and intrusion of rainwater and dust from the outside.
[0005]
The constant velocity universal joint 70 includes an outer joint member 71, a joint inner ring (not shown), a cage, and a torque transmission ball. The outer joint member 71 has a cup-shaped mouth portion 72 and a shaft portion 73 extending in the axial direction from the mouth portion 72, and a curved track groove 72 a extending in the axial direction is formed on the inner periphery of the mouth portion 72. ing.
[0006]
The shaft portion 73 of the outer joint member 71 formed in a hollow shape is fitted into the hub wheel 50, and an uneven portion 53 that is cured on the inner peripheral surface of the hub wheel 50, and a cylindrical small-diameter stepped portion 54 is formed at the end. Then, the diameter of the shaft portion 73 is expanded to bite into the concavo-convex portion 53, and the fitting portion is crimped to plastically connect the hub wheel 50 and the outer joint member 71 (Japanese Patent Laid-Open No. 2001-18605).
[0007]
In the conventional drive wheel bearing device described above, the looseness of the fitting portion can be prevented and the wear of the fitting portion can be suppressed compared to torque transmission means such as serrations, so that the durability and handling stability of the device can be reduced. Can be improved. In addition, since this coupling portion has both the torque transmission means and the coupling means for the hub wheel and the outer joint member, a fixing means such as a fastening nut is not required, and the apparatus can be further reduced in weight and size.
[0008]
[Problems to be solved by the invention]
However, in the drive wheel bearing device, when an excessive bending moment load is generated during turning of the vehicle, the butted portion between the hub wheel and the outer joint member becomes a node and repeatedly receives the bending load. At this time, excessive stress is generated in the small-diameter step portion of the thin hub ring, and the strength and durability may be reduced.
[0009]
The present invention has been made in view of such circumstances, and it is intended to provide a drive wheel bearing device in which the strength and durability of the device are improved while the device is lightweight and compacted by plastic coupling. It is aimed.
[0010]
[Means for Solving the Problems]
In order to achieve such an object, the invention according to claim 1 of the present invention is that the hub wheel, the constant velocity universal joint, and the double row rolling bearing are unitized, and among the inner rolling surfaces of the double row rolling bearing, One inner rolling surface and a small cylindrical step portion extending in the axial direction from the inner rolling surface are formed on the hub wheel, and the hub wheel and the outer joint member of the constant velocity universal joint are fitted to each other. By forming a hardened uneven portion on the inner peripheral surface of the hub wheel at the fitting portion, and expanding the fitting portion of the outer joint member into the uneven portion, In the drive wheel bearing device in which the outer joint member is integrally plastically coupled, the uneven portion is composed of an independent annular groove formed by turning and an axial groove formed by broaching orthogonal to the groove. And shape by this broaching The groove diameter is a diameter smaller than the inner diameter of the cylindrical portion, the convex portion of the concavo-convex portion is formed in a triangular shape spire shape.
[0011]
As described above, the concave and convex portions are constituted by independent annular grooves formed by turning and axial grooves formed by broaching orthogonal thereto, and the diameter of the groove formed by broaching is reduced to a small diameter step. Since the convex portion of the concavo-convex portion is formed in a triangular spire shape, the torque can be efficiently transmitted from the outer joint member to the hub wheel by a plurality of parallel axial grooves. In addition, both members can be fixed in the axial direction without play by a plurality of parallel annular grooves, and good biting property can be secured, and the teeth of the broach pass through the inner diameter of the small diameter step portion. In this case, it is possible to avoid scratches that occur at the time, and to ensure the strength and durability of the small-diameter step portion of the hub wheel that is the weakest portion.
[0015]
The invention according to claim 2 employs a so-called fourth generation structure in which one of the inner rolling surfaces of the double row rolling bearing is formed on the hub wheel and the other is formed on the outer joint member. This makes it possible to minimize the number of fitting parts and parts such as the fitting between the bearing part and the hub wheel, and misalignment of the fitting part is cumulatively added to the wheel mounting flange of the hub wheel, so that Since it is possible to suppress adverse effects on vibration, the device can be further reduced in weight and size, and durability and steering stability can be improved.
[0016]
Preferably, when a hardened layer is formed on the surface from the inner rolling surface to the end surface of the small-diameter step portion and the inner diameter of the end portion as in the invention described in claim 3 , the small-diameter step portion and the cylindrical surface are fitted. Wear with the shaft portion of the mating outer joint member is suppressed.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a longitudinal sectional view showing an embodiment of a drive wheel bearing according to the present invention.
[0019]
This drive wheel bearing device comprises a hub wheel 1, a double row rolling bearing 2 and a constant velocity universal joint 3 as a unit. In the following description, the side closer to the outside of the vehicle in the state assembled to the vehicle is referred to as the outboard side (left side in the drawing), and the side closer to the center is referred to as the inboard side (right side in the drawing).
[0020]
The hub wheel 1 integrally has a wheel mounting flange 4 for mounting a wheel (not shown) at an end portion on the outboard side. Concave and convex portions 5 are formed on the inner peripheral surface of the hub wheel 1, and the hardened layer 10 is formed with a surface hardness in the range of 54 to 64 HRC by heat treatment (indicated by a dotted pattern in the figure). As the heat treatment, local heating is preferable, and quenching by high-frequency induction heating that can set the hardened layer depth relatively easily is preferable.
[0021]
In addition, the uneven | corrugated | grooved part 5 can illustrate the shape which orthogonally crossed the groove | channel of several rows as shown to FIG. 2 and FIG. FIG. 2 shows the formation of the iris knurl-like uneven portion 5 in a process including broaching. First, as shown in FIG. 2A, a plurality of rows parallel to the inner periphery of the hub wheel 1 by cutting such as turning. Then, as shown in FIG. 2B, a plurality of parallel axial grooves 5b orthogonal to the annular groove 5a are formed by broaching. The order of formation of the annular groove 5a and the axial groove 5b is not particularly limited, and the axial groove 5b may be formed first, contrary to the above.
[0022]
Here, the inner diameter of the small-diameter step portion 1b formed at the end of the hub wheel 1 is D1, the inscribed circle diameter of the annular groove 5a is D2, and the groove bottom diameter is D4, while the groove bottom diameter of the axial groove 5b is By setting D1> D3 when D3 is set, it is possible to prevent scratches caused by the passage of the broach teeth in the inner diameter D1 portion during broaching. In this embodiment, the dimensional relationship between D1 and D2 is D1> D2, and the dimensional relationship between D4 and D1 is set to D4 = D1. However, either D4 or D1 may have a large diameter. The small-diameter step portion 1b of the hub wheel 1 that is the weakest portion with respect to repeated bending stress has not only such scratches but also a relationship with the in-wax clearance with the shaft portion 17 of the outer joint member 14 to be described later, which is delicately strong. It has been found from the durability test conducted by the present applicant that it affects the durability.
[0023]
In this embodiment, the radial clearance between the small-diameter step portion 1b of the hub wheel 1 and the shaft portion 17 of the outer joint member 14 is suppressed as compared with the conventional case and set to 0.5 mm or less. The smaller the clearance in the radial direction of the inlay fitting portion, the more advantageous because it is possible to suppress the deformation of the hub wheel 1, but here, considering the ease of fitting, 0.50 to -0.10 mm. Preferably, it is set to 0.35 to -0.05 mm. Thereby, the deformation of the small-diameter step portion can be suppressed against repeated bending loads, and the load can be reliably received by the cylindrical surface, so that the durability of the apparatus can be significantly improved.
[0024]
Here, although the uneven part 5 illustrated the iris knurl-like uneven part 5 with the annular groove 5a and the axial groove 5b orthogonal to the annular groove 5a, it may be a single spiral groove instead of the annular groove 5a. It has the same function as the annular groove 5a and can be easily formed by turning or the like.
[0025]
In addition, as shown in FIG. 3, the first spiral groove 6a is formed by a plurality of times of helical broaching, and then the second helical broaching is performed axially symmetrically to thereby form the second spiral groove 6b. By forming it, the iris knurl-like uneven portion 6 can also be formed. Here, the first spiral groove 6a may be formed by cutting such as turning. Further, the convex portions of the concavo-convex portions 5 and 6 are formed in a spire shape such as a triangular shape in order to ensure good biting property.
[0026]
The double row rolling bearing 2 includes an outer member 7, an inner member 8, and double row rolling elements 9, 9. The outer member 7 is a vehicle body mounting flange for mounting to the vehicle body (not shown) on the outer periphery. 7a is integrally formed, and double row outer rolling surfaces 7b and 7b are formed on the inner periphery. On the other hand, the inner member 8 refers to the hub wheel 1 and an outer joint member 14 to be described later. The inner rolling surface 1a on the outboard side facing the outer rolling surfaces 7b and 7b of the outer member 7 is connected to the hub wheel 1. An inner rolling surface 14a on the inboard side is formed on the outer periphery and on the outer periphery of the outer joint member 14, respectively. Double row rolling elements 9, 9 are accommodated between the rolling surfaces 7b, 1a and 7b, 14a, respectively, and are held by the retainers 11, 11 so as to be freely rollable. Seals 12 and 13 are attached to the ends of the double-row rolling bearing 2 to prevent leakage of lubricating grease sealed inside the bearing and intrusion of rainwater and dust from the outside.
[0027]
On the outer periphery of the hub wheel 1, induction hardening is applied to the surface of the small-diameter step portion 1b which is in contact with the seal land portion where the seal lip of the seal 12 is slidably contacted, the inner rolling surface 1a, and the shoulder portion 16 of the outer joint member 14 to be an in-row portion To form a hardened layer 10 '(shown as a dotted pattern in the figure). Here, the double-row rolling bearing 2 is exemplified as a double-row angular ball bearing in which the rolling elements 9 and 9 are balls. However, the double-row rolling bearing 2 is not limited to this and may be a double-row tapered roller bearing using a tapered roller as the rolling element. .
[0028]
The constant velocity universal joint 3 includes an outer joint member 14, a joint inner ring N, a cage C, and a torque transmission ball B. The outer joint member 14 has a cup-shaped mouth portion 15, a shoulder portion 16 that forms the bottom portion of the mouth portion 15, and a shaft portion 17 that extends from the shoulder portion 16 in the axial direction. A curved track groove 15a extending in the axial direction is formed.
[0029]
The outer joint member 14 is formed in a hollow shape, and the inner rolling surface 14 a described above is formed on the outer periphery of the shoulder portion 16. The shaft portion 17 of the outer joint member 14 has a small diameter step portion 17a and a fitting portion 17b. The small diameter step portion 1 b of the hub wheel 1 press-fitted into the small diameter step portion 17 a is abutted against the shoulder portion 16 of the outer joint member 14, and the fitting portion 17 b is fitted into the hub wheel 1. Thereafter, the fitting portion 17b is expanded in diameter by an appropriate means such as inserting / withdrawing a mandrel into / from the inner diameter of the fitting portion 17b, so that the concave / convex portion 5 of the hub wheel 1 is bitten into the hub wheel 1 and the outer joint member 14. And are plastically connected. As a result, since this coupling portion has both the torque transmission means and the coupling means for the hub wheel 1 and the outer joint member 14, it is necessary to form a conventional torque transmission means such as serration on the hub wheel 1 or the outer joint member 14. In addition, since fixing means such as a fastening nut is not required, the apparatus can be further reduced in weight and size.
[0030]
In the outer joint member 14, the hardened layer 10 ″ is applied to the surface over the rolling surface 14 a and the small diameter step portion 17 a from the seal land portion in which the seal groove 13 is in sliding contact with the track groove 15 a formed on the inner periphery of the mouth portion 15. Hardening by high-frequency induction heating is suitable as the curing treatment, and the fitting portion 17b whose diameter is expanded is an unquenched portion having a surface hardness of 24HRC or less after forging, and the uneven portion 5 of the hub wheel 1 described above. It is preferable to set the hardness difference between the surface hardness of 54 and 64 HRC to 30 HRC or more, so that the fitting portion 17b can easily and deeply bite into the uneven portion 5, and the tip of the uneven portion 5 can be firmly crushed. Both can be plastically bonded.
[0031]
An end cap E formed by pressing a steel plate is attached to the inner diameter of the hollow outer joint member 14 to prevent leakage of the lubricating grease enclosed in the mouth portion 15 to the outside and dust intrusion from the outside. Yes.
[0032]
The embodiment of the present invention, that is, the so-called fourth generation structure in which one of the inner rolling surfaces of the double row rolling bearing is formed on the hub wheel and the other is formed on the outer joint member has been described. Of course, the present invention is not limited to these embodiments, but is merely an example, and can be implemented in various forms without departing from the gist of the present invention. The scope of the present invention is defined by the terms of the claims, and includes the equivalent meanings of the claims and all modifications within the scope. For example, one of the inner rolling surfaces of the double row rolling bearing is formed on a hub ring, the other rolling surface is formed on a separate inner ring, and the inner ring is press-fitted into a small diameter step portion of the hub ring. A so-called third generation structure may be used.
[0033]
【The invention's effect】
As described in detail above, the drive wheel bearing device according to the present invention forms an uneven portion in which the fitting portion between the hub wheel and the outer joint member of the constant velocity universal joint is cured on the inner peripheral surface of the hub wheel. In the drive wheel bearing device in which the hub wheel and the outer joint member are integrally plastically bonded by enlarging the engagement portion of the outer joint member into the uneven portion, the uneven portion is turned by turning. It is composed of an independent annular groove formed and an axial groove formed by broaching orthogonal to this, and the groove diameter formed by this broaching is smaller than the inner diameter of the small diameter step part, Since the protrusion is formed in a triangular spire shape, torque can be efficiently transmitted from the outer joint member to the hub wheel by a plurality of parallel axial grooves, and a plurality of parallel annular grooves By loosening both parts Ku shaft can be secured to the direction, and it is possible to ensure good biting properties, it can broach teeth to reliably prevent the abrasion that occurs when passing through the inner diameter of the cylindrical portion, weakest portion The strength and durability of the small-diameter step portion of the hub wheel can be ensured.
[0034]
In addition, the small-diameter step portion of the hub wheel and the shaft portion of the outer joint member are in-row portions, and the radial clearance thereof is suppressed to 0.5 mm or less including shimeshiro. Since the deformation can be suppressed and the load can be reliably received by the cylindrical surface, the durability of the apparatus can be remarkably improved.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing an embodiment of a bearing device for a drive wheel according to the present invention.
FIG. 2 (a) is a longitudinal sectional view showing the shape of an uneven portion of a hub wheel according to the present invention.
(B) is the principal part side view which shows an axial direction groove | channel same as the above.
FIG. 3 is a longitudinal cross-sectional view showing a process of forming a concavo-convex portion of a hub wheel according to the present invention.
FIG. 4 is a longitudinal sectional view showing a conventional drive wheel bearing device.
[Explanation of symbols]
1 ..... Hub wheel 1a, 14a ..... Inner rolling surface 1b, 17a ..... Small diameter step 2 ....・ ・ ・ ・ ・ Double row rolling bearing 3 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Constant velocity universal joint 4 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Wheel mounting flanges 5, 6 ・ ・ ・ ・··················································· Annular groove 5b One spiral groove 6b ········· Second spiral groove 7 ········ Outside member 7a ······ Body Mounting flange 7b ··· Outer rolling surface 8 ··········· Inner member 9 ············ Rolling element 10 10 ', 10 "... Hardened layer 11 ... Retainer 12, 13 ... Seal 14 ... Outer joint member 15 ... Mouse part 15a ... Track groove 16 ...・ ・ ・ ・ ・ Shoulder 17 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Shaft 17b ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Fitting 50 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Hub wheel 50a , 61a, 71a ··· Rolling surface 51 ··· Wheel mounting flange 52 ···························································· 54 ... Small diameter step 60 ... Bearing 61 ... Outer member 62 ...・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Inner member 63 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Rolling element 64 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Car body mounting flange 65 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・・ Retainers 66, 67 ... ・ ・ ・ ・ ・ Seal 70 ...・ ・ ・ Constant velocity universal joint 71 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Outer joint member 72 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Mouse part 72a ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Track Groove 73 ... Shaft B ... Torque transmission ball C ... Cage D1 ... ·············· Inner diameter D2 of the small diameter step ············· Inscribed circle diameter D3 of the annular groove ····················· D4 ··························· End groove E

Claims (3)

A hub wheel, a constant velocity universal joint, and a double row rolling bearing are unitized, and one inner rolling surface of the inner rolling surfaces of the double row rolling bearing and a cylinder extending in the axial direction from the inner rolling surface. Formed in the hub wheel, the hub wheel and the outer joint member of the constant velocity universal joint are fitted, and the concave and convex portions hardened on the inner peripheral surface of the hub wheel at the fitting part. In the drive wheel bearing device in which the hub wheel and the outer joint member are integrally plastically coupled by forming a portion and encroaching the fitting portion of the outer joint member into the uneven portion.
The concavo-convex portion is composed of an annular groove formed by turning and an axial groove formed by broaching perpendicular to the groove, and the groove diameter formed by broaching is determined from the inner diameter of the small diameter step portion. And a convex portion of the concavo-convex portion is formed in a triangular spire shape . Driving wheel bearing apparatus of claim 1, the other inner raceway surface of the inner raceway surface formed on the outer joint member in a rolling bearing of the double row. The end face of the inner raceway surface the cylindrical portion, and the driving wheel bearing apparatus of claim 1 or 2 on the surface leading to an end portion inner diameter to form a cured layer.

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