JP2005289255A - Driving wheel hub unit for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a driving wheel hub unit for a vehicle, which reduces stick-slip abnormal sound without spoiling reliability of the vehicle, an installation property in manufacture, workability, etc. <P>SOLUTION: This driving wheel hub unit for the vehicle has a bearing outer periphery of which is fitted on the car body side and on an inner periphery of which a flange part to mount a wheel is fitted and an outboard part spline-connected to the flange part and to transmit drive shaft torque transmitted through a constant velocity joint to the flange part, and it is designed so that a portion free to be distorted in the peripheral direction is formed on a wheel side end part of the outboard part, and that the outboard part makes contact with the bearing or the flange part only through the above portion. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention generally relates to a hub unit used for a drive wheel of a vehicle, and more particularly to a vehicle drive with reduced stick-slip noise without impairing the reliability of the vehicle, assembling and workability during manufacture. It relates to a wheel hub unit.

  A hub bearing whose outer periphery is fitted to the vehicle body side and a flange for mounting a wheel is fitted to the inner periphery, and a wheel mounting flange are spline-coupled to each other, and the drive shaft torque transmitted through the constant velocity joint is applied to the hub bearing. In a vehicle drive wheel hub unit having a drive shaft / outboard that transmits to a flange, when driving torque is transmitted, a circumferential direction is formed at the contact portion between the wheel side end surface of the drive shaft / outboard and the vehicle inner end surface of the hub bearing inner ring. There is a problem that slip noise (so-called stick-slip unusual noise) due to torsion (around the axis) can occur.

Conventionally, as a countermeasure for solving this problem, a) an uneven portion is provided in a contact portion between a wheel side end surface of a drive shaft / outboard and a vehicle inner end surface of a hub bearing inner ring to increase frictional resistance, A method of suppressing stick-slip noise by suppressing the occurrence of slip itself in the vehicle (see, for example, Patent Document 1), b) Between the wheel side end surface of the drive shaft / outboard and the vehicle inner end surface of the hub bearing inner ring A method of suppressing stick-slip noise by disposing a spacer made of rubber or resin capable of absorbing torsion to prevent direct contact between both (see, for example, Patent Document 1), and c) Apply grease to the contact area between the wheel side end surface of the drive shaft and outboard and the vehicle inner end surface of the hub bearing inner ring to reduce frictional resistance. Illusion, a method to improve the suppression of the stick slip noise by sliding between both actively (for example, see Non-Patent Document 1), and the like have been proposed.
JP 2003-97588 A Mikio Sakurai, 5 others, “Study on stick-slip noise around bearings of driving wheels”, Honda R & D Technical Review, April 2003, Vol. 15, no. 1, p. 173-180

  However, the above conventional measures have the following problems.

  First, in the method of suppressing the slip itself as in the method described in Patent Document 1, the overall structure of the hub unit is not changed. Therefore, if the drive torque is transmitted, Relative torsion occurs as usual with the hub bearing.

  Therefore, even if the contact portion between the wheel side end surface of the drive shaft / outboard and the vehicle inner end surface of the hub bearing inner ring does not slide, the other portion slips instead to generate abnormal noise, or the contact portion The strain energy is accumulated, and is suddenly released when the threshold value is exceeded. This causes a problem that stick-slip unusual noise is generated from the contact portion.

  In addition, in the method of b) arranging the spacer as in the method described in Patent Document 1 above, the spacer needs to have a sufficient thickness to absorb the twist, and such a separate part is newly added. Assembling and workability deteriorate due to the addition.

  Further, since the axial force due to the nut fastening and the heat from the drive shaft are transmitted from the arrangement location to the spacer, there is a possibility that the spacer may sag in the case of rubber or resin. That is, it is difficult to achieve both absorptivity against torsion and durability of the spacer itself. Once the spacer is bent, the axial force of the nut decreases, which may cause reliability problems such as backlash of the torque transmission spline and inner ring creep of the hub bearing.

  Furthermore, as in the method described in Non-Patent Document 1 described above, c) a method of actively sliding, wear due to aging of grease, grease flow due to muddy water, deterioration of working environment due to application of grease during assembly, cost It causes problems such as high.

  As described above, the above-described conventional measures have a problem that stick-slip abnormal noise cannot be reduced, or even if it can be reduced to some extent, a more serious new problem is caused.

  The present invention is for solving such problems, and provides a vehicle drive wheel hub unit that reduces stick-slip noise without impairing the reliability of the vehicle and the assembly and workability during manufacturing. The main purpose is to provide.

A first aspect of the present invention for achieving the above object is a bearing in which an outer periphery is fitted to the vehicle body side, and a flange portion for attaching a wheel is fitted to the inner periphery.
A vehicle drive wheel hub unit having an outboard portion that is spline-coupled to the flange portion and transmits a drive shaft torque transmitted through a constant velocity joint to the flange portion,
A part that can be twisted in the circumferential direction is formed at the wheel side end of the outboard part,
The outboard part is a vehicle drive wheel hub unit designed to contact the bearing or the flange part only through the part.

  In this first aspect, the part is designed to have a torsional rigidity smaller than the frictional force of the contact portion between the wheel side surface of the outboard part and the bearing inner ring. In other words, it is designed to have a torsional rigidity that starts torsion before the contact portion between the wheel side surface of the outboard portion and the bearing inner ring starts to slide during driving torque transmission.

  According to this first aspect, when driving torque is transmitted, the torsion occurring between the wheel side end surface of the outboard and the bearing inner ring is absorbed by twisting the low-rigidity portion, so the wheel side end surface of the outboard The contact portion between the bearing and the inner ring of the bearing does not slip, and stick-slip noise is suppressed.

  In this first aspect, it is preferable that the part is formed by providing a groove extending in the radial direction on the wheel side end surface of the outboard part without using an additional member.

  In addition, the groove preferably cuts out the outer peripheral edge of the wheel-side end surface of the outboard portion in order to realize sufficiently small torsional rigidity while maintaining the durability of the outboard portion. This is because if the outer peripheral edge is notched, the torsional rigidity in the circumferential direction is greatly reduced as compared to the case where the entire outer peripheral edge is connected.

  Further, in order to further reduce the torsional rigidity in the circumferential direction and sufficiently absorb the torsion, a groove extending in the circumferential direction may be further provided on the wheel side end surface of the outboard portion. The groove extending in the circumferential direction is preferably an annular groove so that the torsional rigidity is uniform in any direction.

  ADVANTAGE OF THE INVENTION According to this invention, the drive-wheel hub unit for vehicles which reduced the stick-slip noise can be provided, without impairing the reliability of a vehicle, the assembly | attachment property / workability | operativity at the time of manufacture, etc.

  Hereinafter, the best mode for carrying out the present invention will be described with reference to the accompanying drawings. The basic concept of the vehicle drive wheel hub unit, the main hardware configuration, the operating principle, the basic control method, and the like are known to those skilled in the art and will not be described in detail.

  FIG. 1 is a longitudinal sectional view of a vehicle drive wheel hub unit according to an embodiment of the present invention. The hub unit 100 rotatably supports the hub 101 with bearings. This bearing includes an outer ring 102, an outer inner ring 103, an inner inner ring 104, and a rolling element 105 that is sandwiched between the outer ring 102 and the inner rings 103, 104 so as to allow rolling.

  The outer ring 102 is press-fitted into a hole 107 provided in the knuckle 106 and is prevented from coming off by a snap ring 108 such as a snap ring. A double row outer ring raceway 109 for the rolling elements 105 is provided on the inner peripheral surface of the outer ring 102.

  A first inner ring raceway 110 and a second inner ring raceway 111 are provided on the inner peripheral surfaces of the outer inner ring 103 and the inner inner ring 104, respectively.

  The hub 101 has a flange 112 for attaching a wheel (not shown). The wheel is attached to the flange 112 by fastening a bolt 113 and a nut (not shown).

  The hollow cylindrical center portion of the hub 102 is press-fitted into the bearing inner peripheral surface 114. A female spline 115 is provided on the inner peripheral surface of the center portion of the hub 102.

  A constant velocity joint 116 provided at the end of a drive shaft (not shown) includes a constant velocity joint outer ring (drive shaft / outboard) 117, a constant velocity joint inner ring 118, and a male spline shaft (outboard shaft) 119. The drive board / outboard 117 and the outboard shaft 119 constitute an outboard portion 120.

  The outboard shaft 119 is configured to be engageable with the female spline 115 and is provided at a wheel side end portion (outer end portion) of the outboard portion 120.

  The drive shaft / outboard 117 is provided at the vehicle inner end portion (inner end portion) of the outboard portion 120. Outer engagement grooves 121 extending in a direction perpendicular to the circumferential direction are formed at a plurality of locations in the circumferential direction on the inner circumferential surface of the drive shaft / outboard 117.

  A female spline 122 is formed at the center of the constant velocity joint inner ring 118, and an inner engagement groove 123 that extends in a direction perpendicular to the circumferential direction and faces the outer engagement groove 121 is formed on the outer peripheral surface thereof. .

  Between each of the inner engagement grooves 123 and each of the outer engagement grooves 121, there is provided a rolling element 125 that is held by a retainer 124 and can roll along the grooves.

  The outboard shaft 119 is inserted through the female spline 115 of the hub 101 from the inside to the outside, and a nut 127 is screwed into a male screw portion 126 provided on a portion of the outboard shaft 119 protruding from the outer end surface of the hub 101. By being tightened further, the hub unit 100 is coupled and fixed.

  In this state, the vehicle inner end surface 128 of the inner inner ring 104 is in contact with the wheel side end surface 129 of the drive shaft / outboard 117 and is prevented from coming off. At the same time, an appropriate preload is applied to each of the rolling elements 105.

  In such an assembled state, the male spline portion provided at the vehicle side end portion of the drive shaft (drive shaft) (not shown) is spline-engaged with the female spline 122 provided at the center portion of the constant velocity joint inner ring 118. The

  A drive shaft (not shown) is loaded with a drive torque from the engine through a constant velocity universal joint, causing the drive shaft to twist. Since the outboard shaft 119 is fixed to the hub 101 by spline coupling, and the hub 101 does not move due to inertia at first, when the driving torque is transmitted to the drive shaft, the rigidity of the hub 101 and the bearing and the outboard shaft 119 is increased. A difference occurs in the twist angle from the difference, and the drive shaft / outboard 117 tends to shift in the driving rotation direction with respect to the bearing. At that time, as described above, slip that causes stick-slip noise occurs on the contact surface where the vehicle inner end surface 128 of the inner inner ring 104 contacts the wheel side end surface 129 of the outboard 117.

  Therefore, in the present embodiment, the wheel side end portion of the drive shaft / outboard 117 is thinned, and specifically, a groove is provided on the wheel side end surface 129 of the drive shaft / out board 117 by, for example, machining. Stiffen. This is intended to make the wheel side end of the drive shaft / outboard 117 easy to twist in the circumferential direction (around the axis) by reducing the rigidity of the portion that contacts the inner inner ring 104.

  In this embodiment, as shown in FIG. 2, the wheel-side end surface 129 of the drive shaft / outboard 117 communicates with the annular circumferential groove 130 and the circumferential groove 130, and the outer peripheral edge of the end surface 129 is cut. A missing radial groove 131 is provided.

  In other words, in this embodiment, as best shown in FIG. 2, there are two notches, an outer peripheral wall that contacts the vehicle inner end surface 128 of the inner inner ring 104, and the outboard shaft 119. A predetermined depth is depressed from the wheel side end surface 129 of the drive shaft / outboard 117, leaving a root portion.

  By reducing the rigidity of the wheel side end of the drive shaft / outboard 117 in this way, when drive torque is applied to the drive shaft, only this part having the lower rigidity than other parts is the first. Twist.

  Therefore, according to the outboard structure as described above, the difference in torsion angle between the hub 101 and the bearing and the outboard shaft 119 at the time of driving as described above is provided (the grooves 130 and 131 are provided). Part) is absorbed by torsion, and no slip occurs on the contact surface where the vehicle inner end surface 128 of the inner inner ring 104 contacts the wheel side end surface 129 of the outboard 117.

  By the way, when forming this low-rigidity part, it is necessary to design so as to satisfy the following two conditions. The first point is that an axial force is applied to the wheel side end surface 129 of the outboard 117, which is the only contact point with the hub bearing in the outboard portion 120, by the nut 127 fastening. The design condition is that a sufficient area for receiving the axial force must be secured on the wheel side end surface 129 of the outboard 117.

  The second point is that the torsional rigidity in the circumferential direction (around the axis) of this low-rigidity portion must be smaller than the frictional force of the contact portion between the wheel side end surface 129 of the outboard portion 120 and the vehicle inner end surface 128 of the inner inner ring 104. In other words, when transmitting the driving torque, the design condition is that the low-rigidity portion provided at the end of the outboard 117 must start to twist before the contact portion starts to slide.

  In this regard, according to the present embodiment, the portion having a relatively low torsional rigidity provided at the wheel side end of the outboard portion 120 is formed in a single member by providing a groove in the outboard 117. The torsional rigidity can be reduced while maintaining the rigidity against axial pressing.

  In particular, by providing not only the circumferential groove 130 but also the radial groove 131 so that notches are formed in the outer peripheral edge, the torsional rigidity is greatly reduced while maintaining the axial rigidity in the same member. be able to.

  Next, with reference to FIG. 3, the outboard structure according to the present embodiment will be described with examples of dimensions.

When the size of the portion A shown in FIG. 3A is 26 millimeters (mm) in diameter, the axial length is 10 mm, and the lateral elastic modulus of the material (for example, iron) is 78,000 N / mm ² , the twist angle of the portion A θ (rad) is calculated using the drive torque T (Nm).
θ = (T × 10) / (78,000 × 26 ⁴ × π / 32)
Therefore, the torsional rigidity T / θ is
T / θ = 3.5 × 10 ⁸ (Nmm / rad) ≈6,000 (Nm / deg)
It can be asked.

The driving torque T is assumed to be 180 Nm in a 1.8 liter class engine, assuming that the first gear ratio is 3.5 and the differential gear ratio is 4.
T = 180 × 3.5 × 4 = 2,520 (Nm)
Therefore, after all, the portion A depends on the driving torque T, and θ = 2,520 / 6,000 = about 0.4 (deg).
You can estimate if you try to twist.

  On the other hand, the inventor of the present application conducted an experiment to reduce stick-slip noise by shortening the axial length of the portion A and increasing the torsional rigidity of the portion A. Then, when the axial length of the portion A was halved (in the above example of dimensions, when 10 mm was changed to 5 mm), an effect was seen in improving stick-slip noise. When the axial length of the portion A is halved, the twist angle is also halved. Therefore, it can be estimated that the stick-slip abnormal noise is improved if the twist angle is reduced to less than half. In addition, the method of shortening the axial length of the portion A in this way is a method limited to experiments, and it is considered difficult to apply to a real vehicle because of the structure of the drive wheel hub unit.

  If this is applied to the torsion angle 0.4 degrees of the part A calculated above, the target value is to suppress the torsion angle of the part A to half of 0.2 degrees or less by the low rigidity portion.

Here, the thickness center line diameter d ₀ of the wheel side end surface 129 of the outboard 117 is 50 mm, the inner diameter d _{1 is} 38 mm, the depths l _{1 of} the circumferential grooves 130 and the radial grooves 131 are 10 mm, and the notch width ( When the lateral width of the radial groove 131 is l ₂ (mm) and the outer peripheral wall thickness is t (mm), the twist angle θX (deg) at the groove bottom surface X is I _p = 20,400.
θ _X = twist angle of portion A + (2,520 × 10 ³ × l ₁ ) / (78,000 × 20,400) × (180 / π) = 0.4 + 0.09≈0.5 (deg)
Here, the nut tightening axial force is 50,000 N, the contact portion (unlubricated) of the wheel side end surface 129 of the outboard 117 (for example, iron) and the vehicle inner end surface 128 of the inner ring 104 (for example, iron) of the hub bearing. When the friction coefficient is 0.25, the torque (Nm) supported by this contact portion is
50,000 × 0.5 × 0.25 × 0.05 = 310 (Nm)
It becomes. Due to this torque 310 Nm, the low rigidity portion provided at the wheel side end portion of the outboard portion 120 is twisted, and the twist angle in the cross section X is absorbed.

If the torsion angle θ _a (deg) at this low rigidity portion is negligible because the notch width l2 is small,
θ _a = (3 × 310 × 10 ³ × l ₁ ) / (50/2 × π × t ³ × 78,000) × 180 / π = 87 / t ³ (deg)
It can be asked. Here, since the target value of theta _a is 0.2 degrees as described above, if t ≒ 7 (mm), will be able to absorb the torsion angle of 0.2 degrees.

In this case, the surface pressure that receives the nut axial force is
50,000 / (50/2 × π × 7) ≈90 (N / mm ² )
Thus, there is no problem in terms of durability.

  Thus, according to the above dimension example, at the wheel side end portion of the outboard portion 120, an annular circumferential groove 130 is provided to a depth of 10 mm around the axis, leaving an edge with a thickness of 7 mm on the outer periphery. It can be expected that stick-slip noise can be reduced by providing one or more notches (radial grooves 131) on the edge.

  Thus, the outboard structure according to the present embodiment has a sufficient effect of reducing stick-slip abnormal noise in light of the above-described realistic dimension example.

  As described above, according to this embodiment, even when a driving torque is transmitted and a relative twist is generated between the bearing and the outboard, the twist is the outboard provided with the grooves 130 and 131. Since the low rigidity portion of the end portion is absorbed by twisting, the contact portion between the vehicle inner end surface 128 of the inner ring 104 of the hub bearing and the wheel side end surface 129 of the outboard 117 is prevented from slipping, and the stick-slip noise Is reduced.

  In the above embodiment, the case where the wheel side end surface 129 of the drive shaft outboard 117 abuts on the vehicle inner end surface 128 of the inner inner ring 104 has been described, but the present invention is not limited to this, and the drive shaft outboard is not limited thereto. The wheel-side end surface 129 of 117 may abut the vehicle inner end surface of the hollow cylindrical center portion of the hub 102. However, from the viewpoint of suppressing the surface pressure due to the axial force of the wheel side end surface 129 of the drive shaft / outboard 117 as much as possible and suppressing the surface pressure due to the axial force, it is larger than the vehicle inner end surface of the hollow cylindrical center portion of the hub 102 in the radial direction. It is preferable to abut the vehicle inner end face 128 of the inner inner ring 104 located on the outer diameter side.

  As a modification of the above embodiment, the inner inner ring 104 may be fixed in the axial direction by crimping the inner end of the hub 101 outward. Further, instead of providing the outer inner ring 103 of the hub bearing, this portion may be a raceway surface formed on the outer periphery of the hub 101. Furthermore, in the above embodiment, the case where a sphere (ball) is used as the rolling element 105 is shown as an example. However, the present invention is not limited to this, and any other type of rolling element such as a conical roller is used. be able to.

  The present invention can be used for a vehicle drive wheel hub unit. The appearance, weight, size, running performance, etc. of the vehicle to be mounted are not limited.

1 is a longitudinal sectional view of a vehicle drive wheel hub unit according to an embodiment of the present invention. It is a schematic perspective view of the wheel side end part of the outboard part 120 which concerns on one Example of this invention. (A) It is an axial front view of the wheel side end part of the outboard part 120 which concerns on one Example of this invention. (B) It is a side view of the wheel side edge part of the outboard part 120 which concerns on one Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Hub unit 101 Hub 102 Hub bearing outer ring 103 Hub bearing outer inner ring 104 Hub bearing inner inner ring 105 Rolling body 106 Knuckle 107 Hole 108 Retaining ring 109 Outer ring race 110 First inner ring race 111 Second inner ring race 112 Flange 113 Bolt 114 Bearing Inner peripheral surface 115 Female spline 116 Constant velocity joint 117 Drive shaft / outboard (constant velocity joint outer ring)
118 Constant velocity joint inner ring 119 Outboard shaft (male spline shaft)
DESCRIPTION OF SYMBOLS 120 Outboard part 121 Outer engagement groove 122 Female spline 123 Inner engagement groove 124 Cage 125 Rolling body 126 Male thread part 127 Nut 128 Vehicle inner side end surface of inner inner ring 104 129 Wheel side end surface of drive shaft / outboard 117

Claims (5)

A bearing whose outer periphery is fitted to the vehicle body side, and a flange portion for attaching a wheel is fitted to the inner periphery;
A vehicle driving wheel hub unit having an outboard portion that is spline coupled to the flange portion and transmits a drive shaft torque transmitted through a constant velocity joint to the flange portion,
A part that can be twisted in the circumferential direction is formed at the wheel side end of the outboard part,
The vehicle drive wheel hub unit according to claim 1, wherein the outboard portion is designed to contact the bearing or the flange portion only through the portion. The vehicle drive wheel hub unit according to claim 1,
The vehicle drive wheel hub unit according to claim 1, wherein the portion is formed by providing a groove extending in a radial direction on a wheel side end surface of the outboard portion. The vehicle drive wheel hub unit according to claim 2,
The vehicle drive wheel hub unit according to claim 1, wherein the groove cuts out an outer peripheral edge of a wheel side end surface of the outboard portion. The vehicle drive wheel hub unit according to claim 2 or 3,
A vehicle drive wheel hub unit, wherein a groove extending in a circumferential direction is further provided on a wheel side end face of the outboard portion. The vehicle drive wheel hub unit according to claim 4,
The vehicle driving wheel hub unit, wherein the circumferentially extending groove is an annular groove.

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