Rolling device for vehicle

Patent metadata

Field	Value
Publication number	US-10087985-B2
Application number	US-201715660274-A
Country	US
Kind code	B2
Filing date	Jul 26, 2017
Priority date	Sep 29, 2016
Publication date	Oct 2, 2018
Grant date	Oct 2, 2018

Abstract

A rolling device for a vehicle includes an inner raceway member including first and second inner raceways; an outer raceway member including first and second outer raceways; first rolling elements disposed rollably between the first inner raceway and the first outer raceway and second rolling elements disposed rollably between the second inner raceway and the second outer raceway; and grease disposed on raceway surfaces of the first inner raceway, the first outer raceway, the second inner raceway, and the second outer raceway and rolling surfaces of the first rolling elements and the second rolling elements. The grease includes a base oil, a thickener, and additives. The grease includes a synthetic oil as the base oil. A kinematic viscosity of the base oil at 40° C. is 20 mm 2 /s to 50 mm 2 /s. The additives include a phosphorus compound, a calcium compound, and a hydrocarbon wax.

First claim

What is claimed is:

1. A rolling device for a vehicle, comprising:
an inner raceway member including a first inner raceway and a second inner raceway formed on an outer peripheral surface of the inner raceway member;
an outer raceway member including a first outer raceway and a second outer raceway formed on an inner peripheral surface of the outer raceway member;
a plurality of first rolling elements disposed rollably between the first inner raceway and the first outer raceway and a plurality of second rolling elements disposed rollably between the second inner raceway and the second outer raceway; and
grease disposed on a raceway surface of the first inner raceway, a raceway surface of the first outer raceway, rolling surfaces of the plurality of first rolling elements, a raceway surface of the second inner raceway, a raceway surface of the second outer raceway, and rolling surfaces of the plurality of second rolling elements, wherein:
in a case where, on a section including a central axis of the inner raceway member, a first position is a position of the inner raceway member, the outer raceway member, the plurality of first rolling elements, and the plurality of second rolling elements at a time when the plurality of first rolling elements is disposed between the first inner raceway and the first outer raceway and the plurality of second rolling elements is disposed between the second inner raceway and the second outer raceway, each of the first rolling elements and the first inner raceway make contact with each other at a first nominal contact point, each of the first rolling elements and the first outer raceway make contact with each other at a second nominal contact point, each of the second rolling elements and the second inner raceway make contact with each other at a third nominal contact point, and each of the second rolling elements and the second outer raceway make contact with each other at a fourth nominal contact point;
a radius from the central axis of the inner raceway member to the first nominal contact point is a first radius, a radius from the central axis of the inner raceway member to the second nominal contact point is a second radius, a radius from the central axis of the inner raceway member to the third nominal contact point is a third radius, and a radius from the central axis of the inner raceway member to the fourth nominal contact point is a fourth radius;
in a case where the inner raceway member and the outer raceway member are disposed at a same position as the first position while none of the plurality of first rolling elements is disposed between the first inner raceway and the first outer raceway and none of the plurality of second rolling elements is disposed between the second inner raceway and the second outer raceway,
a first length is a length of a first line segment in a direction parallel to the central axis of the inner raceway member, the first line segment connecting a first virtual contact point on the first inner raceway to a second virtual contact point on the first outer raceway, the first virtual contact point being separated in a radial direction parallel to the first radius from the central axis of the inner raceway member by a same distance as the first radius, the second virtual contact point being separated in a radial direction parallel to the second radius from the central axis of the inner raceway member by a same distance as the second radius, and
a second length is a length of a second line segment in a direction parallel to the central axis of the inner raceway member, the second line segment connecting a third virtual contact point on the second inner raceway to a fourth virtual contact point on the second outer raceway, the third virtual contact point being separated in a radial direction parallel to the third radius from the central axis of the inner raceway member by a same distance as the third radius, the fourth virtual contact point being separated in a radial direction parallel to the fourth radius from the central axis of the inner raceway member by a same distance as the fourth radius;

in a case where the plurality of first rolling elements and the plurality of second rolling elements are disposed at a same position as the first position without disposing the inner raceway member and the outer raceway member,
a third length is a length of a third line segment in a direction parallel to the central axis of the inner raceway member, the third line segment connecting a fifth virtual contact point on a surface of each of the first rolling elements to a sixth virtual contact point on the surface of the first rolling element, the fifth virtual contact point being separated in the radial direction parallel to the first radius from the central axis of the inner raceway member by a same distance as the first radius, the sixth virtual contact point being separated in the radial direction parallel to the second radius from the central axis of the inner raceway member by a same distance as the second radius,
a fourth length is a length of a fourth line segment in a direction parallel to the central axis of the inner raceway member, the fourth line segment connecting a seventh virtual contact point on a surface of each of the second rolling elements to an eighth virtual contact point on the surface of the second rolling element, the seven virtual contact point being separated in the radial direction parallel to the third radius from the central axis of the inner raceway member by a same distance as the third radius, the eighth virtual contact point being separated in the radial direction parallel to the fourth radius from the central axis of the inner raceway member by a same distance as the fourth radius;

the first length is set to be shorter than the third length and the second length is set to be shorter than the fourth length;
the grease includes a base oil, a thickener, and additives;
the grease includes a synthetic oil as the base oil;
a kinematic viscosity of the base oil at 40° C. is 20 mm 2 /s to 50 mm 2 /s; and
the additives include a phosphorus compound, a calcium compound, and a hydrocarbon wax.

2. The rolling device for the vehicle, according to claim 1 , wherein a range of a total sum of a value obtained by subtracting the third length from the first length and a value obtained by subtracting the fourth length from the second length is −0.06 mm to −0.1 mm.

3. The rolling device according to claim 1 , wherein the thickener includes a compound including a urea group.

4. The rolling device according to claim 3 , wherein the compound including the urea group includes diurea represented by a following formula (A),

and wherein in the formula (A), R 2 represents a diphenylmethane group; each nitrogen atom, which is bonded to a corresponding one of phenyl groups in R 2 , is in a para-position with respect to a methylene group in the diphenylmethane group; R 1 and R 3 are functional groups which are same or different from each other, and each of R 1 and R 3 represents a cyclohexyl group, or a linear or branched alkyl group having 16 to 20 carbon atoms; and a ratio of a number of moles of the cyclohexyl group to a total number of moles of the cyclohexyl group and the alkyl group [{(Number of Moles of Cyclohexyl Group)/(Number of Moles of Cyclohexyl Group+Number of Moles of Alkyl Group)}×100] is 50 mol % to 90 mol %.

5. The rolling device according to claim 3 , wherein a content of the compound including the urea group is 5 mass % to 15 mass % with respect to a total amount of the grease.

6. The rolling device according to claim 1 , wherein a kinematic viscosity of the synthetic oil at −30° C. is 5000 mm 2 /s or lower.

Assignees

• Jtekt Corp

Inventors

• Inoue Yuya
• Okumura Tsuyoshi
• Wakisaka Teruyuki
• Ina Yoshiyuki
• Hakata Toshihiro
• Onizuka Takaaki

Classifications

• F16C13/02

  Bearings · CPC title

• C10M2219/046

  Overbased sulfonic acid salts · CPC title

• C10M2215/14

  Containing carbon-to-nitrogen double bounds, e.g. guanidines, hydrazones, semicarbazones · CPC title

• C10M2207/2835

  used as base material · CPC title

• C10M2205/14

  Synthetic waxes, e.g. polythene waxes · CPC title