Double-Row Tapered Roller Bearing Unit and Method for Manufacturing Same

Patent metadata

Field	Value
Publication number	US-2016245334-A1
Application number	US-201415026800-A
Country	US
Kind code	A1
Filing date	Sep 30, 2014
Priority date	Oct 4, 2013
Publication date	Aug 25, 2016
Grant date	—

Abstract

Construction of a double-row tapered-roller bearing unit that is able to improve the contact state between the rolling contact surfaces of plural tapered rollers and a first inner-ring raceway ( 7 ) and second inner-ring raceway ( 8 ), and a method of manufacturing the same are provided. The inclination angle θ 1 of the first inner-ring raceway ( 7 ) and the inclination angle θ 2 of the second inner-ring raceway ( 8 ) in a state before the first inner ring ( 10 ) and the second inner ring ( 11 ) are press-fitted onto the fitting surface section ( 13 a ) of the hub main body ( 12 a ), the amount of decrease δθ a in the inclination angle of the first inner-ring raceway ( 7 ) and the amount of decrease δθ b in the inclination angle of the second inner-ring raceway ( 8 ) occurring due to press-fitting of the first inner ring ( 10 ) and the second inner ring ( 11 ) onto the fitting-surface section ( 13 a ), and the amount of increase δθ k in the inclination angle of the first inner-ring raceway ( 7 ) occurring due to formation of the crimped section ( 15 ) are adjusted, so that the inclination angle φ 1 of the first inner-ring raceway ( 7 ) and the inclination angle Θ 2 of the second inner-ring raceway ( 8 ) in a state after the crimped section ( 15 ) has been formed are kept within respective proper ranges.

First claim

What is claimed is:

1 . A double-row tapered-roller bearing unit, comprising:
an outer-diameter-side raceway member having a first outer-ring raceway and a second outer-ring raceway formed on the inner-circumferential surface thereof, the first outer-ring raceway and the second outer-ring raceway having partial conical surfaces inclined in directions so that the diameters become larger going in directions away from each other in the axial direction; an inner-diameter-side raceway member having a first inner-ring raceway and a second inner-ring raceway formed on the outer-circumferential surface thereof, the first inner-ring raceway and the second inner-ring raceway having partial conical surfaces inclined in directions so that the diameters become larger going in directions away from each other in the axial direction; and plural tapered rollers rotatably provided respectively between the first outer-ring raceway and the first inner-ring raceway, and between the second outer-ring raceway and the second inner-ring raceway; and the inner-diameter-side raceway member comprising a first inner ring with the first inner-ring raceway formed on the outer-circumferential surface thereof, a second inner ring with the second inner-ring raceway formed on the outer-circumferential surface thereof, and a shaft member; the first inner ring and the second inner ring press-fitted onto the shaft member; and the first inner ring and the second inner ring connected and fastened to the shaft member by securing the large-diameter-side end surface of the first inner ring by a crimped section formed by elastically deforming one end section in the axial direction of the shaft member, and the relationship of the inclination angle θ 1 of the first inner-ring raceway in the state before the first inner ring is press-fitted onto the shaft member; the inclination angle θ 2 of the second inner-ring raceway in the state before the second inner ring is press-fitted onto the shaft member; the amount of decrease δθ a in the inclination angle of the first inner-ring raceway occurring when the first inner ring is press-fitted onto the shaft member; the amount of decrease δθ b in the inclination angle of the second inner-ring raceway occurring when the second inner ring is press-fitted onto the shaft member; the amount of increase δθ k in the inclination angle of the first inner-ring raceway occurring when the crimped section is formed; the press-fit interference ΔX 1 of the first inner ring with respect to the shaft member; and the press-fit interference ΔX 2 of the second inner ring with respect to the shaft member; satisfying the equation
−θ 1 +δθ a (Δ X 1 )+θ 2 −δθ b (Δ X 2 )=δθ k

and the inclination angle φ 1 of the first inner-ring raceway and the inclination angle Θ 2 of the second inner-ring raceway in the state after the crimped section has been formed being both within respective proper ranges.

2 . The double-row tapered-roller bearing unit according to claim 1 , wherein
the inner-diameter dimension of the first inner ring in the state before the first inner ring is press-fitted onto the shaft member, and the inner-diameter dimension of the second inner ring in the state before the second inner ring is press-fitted onto the shaft member are essentially the same; and a stepped section is provided between the portion onto which the inner ring is press-fitted and the portion onto which the second inner ring is press-fitted of the outer-circumferential surface of the shaft member, and the outer-diameter dimension of the portion of the outer-circumferential surface of the shaft member onto which the first inner ring is press-fitted in the state before the first inner ring is press-fitted onto the shaft member is larger than the outer-diameter dimension of the portion of the outer-circumferential surface of the shaft member onto which the second inner ring is press-fitted in the state before the second inner ring is press-fitted onto the shaft member.

3 . The double-row tapered-roller bearing unit according to claim 2 , wherein a spacer is held on the stepped section between the small-diameter-side end surface of the first inner ring and the small-diameter-side end surface of the second inner ring.

4 . The double-row tapered-roller bearing unit according to claim 2 , wherein the properties of the first inner ring and the second inner ring are essentially equivalent.

5 . The double-row tapered-roller bearing unit according to claim 1 , wherein the portion of the outer-circumferential surface of the shaft member onto which the first inner ring is fitted and the portion of the outer-circumferential surface of the shaft member onto which the second inner ring is fitted define a continuous single cylindrical surface, and the inner-diameter dimension of the first inner ring in the state before the first inner ring is press-fitted onto the shaft member is smaller than the inner-diameter dimension of the second inner ring in the state before the second inner ring is press-fitted onto the shaft member.

6 . The double-row tapered-roller bearing unit according to claim 5 , wherein
the first inner ring has an R chamfer section in the continuous section between the inner-circumferential surface and the large-diameter-side end surface; the second inner ring has an R chamfer section in the continuous section between the inner-circumferential surface and the large-diameter-side end surface that has a larger radius of curvature than that of the R chamfer section of the first inner ring, or has a C chamfer section that has a width dimension in the axial direction and width dimension in the radial direction that are larger than the radius of curvature of the R chamfer section of the first inner ring; and the shaft member has a rotating-side flange for supporting and fastening a wheel in a portion of the outer-circumferential surface that is adjacent to the other side in the axial direction of the portion onto which the second inner ring is press-fitted, and has a corner R section that is arc shaped in the cross section and that is located in the connecting section between the outer-circumferential surface of the shaft member and one side surface in the axial direction of the rotating-side flange in a position that faces the R chamfer section or C chamfer section of the second inner ring, and smoothly connects these surfaces.

7 . A method for manufacturing a double-row tapered-roller bearing unit,
the double-row tapered-roller bearing unit comprising: an outer-diameter-side raceway member having a first outer-ring raceway and a second outer-ring raceway formed on the inner-circumferential surface thereof, the first outer-ring raceway and the second outer-ring raceway having partial conical surfaces inclined in directions so that the diameters become larger going in directions away from each other in the axial direction; an inner-diameter-side raceway member having a first inner-ring raceway and a second inner-ring raceway formed on the outer-circumferential surface thereof, the first inner-ring raceway and the second inner-ring raceway having partial conical surfaces inclined in directions so that the diameters become larger going in directions away from each other in the axial direction; and plural tapered rollers rotatably provided respectively between the first outer-ring raceway and the first inner-ring raceway, and between the second outer-ring raceway and the second inner-ring raceway; and the inner-diameter-side raceway member comprising a first inner ring with the first inner-ring raceway formed on the outer-circumferential surface thereof, a second inner ring with the second inner-ring raceway formed on the outer-circumferential surface thereof, and a shaft member; the fi

Assignees

• Nsk Ltd

Inventors

• Hagiwara Nobuyuki

Classifications

• B60B27/0084

  caulking to fix inner race · CPC title

• F16C2226/12

  by press-fit, e.g. plug-in · CPC title

• B60B27/0005

  with ball bearings · CPC title

• B60B35/02

  Dead axles, i.e. not transmitting torque · CPC title

• F16C2226/52

  with plastic deformation, e.g. caulking or staking · CPC title