# US 2019/0170187 A1 · Ball bearing, spindle device, and machine tool > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2019/0170187 A1 - Document ID: US20190170187A1 - Status: Published application - Kind: A1 - Application number: 16/325,451 - Filed: 2017-08-10 - Published: 2019-06-06 - Earliest claimed: 2016-08-15 - Assignees: Nsk Ltd. - Applicants: Nsk Ltd. - Inventors: Kyohei MATSUNAGA; Yoshiaki KATSUNO - Web page: https://patentgrep.com/patent/US20190170187A1 ## CPC - F16C 19/181: {with angular contact} - F16C 19/28: with two or more rows of rollers - F16C 33/6637: {with liquid lubricant} - F16C 33/6662: {the liquid being carried by air or other gases, e.g. mist lubrication} - F16C 33/78: with a diaphragm, disc, or ring, with or without resilient members {(F16C33/761 takes precedence)} - F16C 19/163: {with angular contact} - F16C 33/586: {outside the space between the races, e.g. end faces or bore of inner ring} - F16C 2322/39: General buildup of machine tools, e.g. spindles, slides, actuators - F16C: SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS ## Abstract In an angular contact ball bearing (10), an outer ring (12) has at least one radial hole (15) passing through in the radial direction from the outer peripheral surface to the inner peripheral surface of the outer ring (12), and the axial-direction position of an inner-diameter-side opening part of the radial hole (15) is located between the groove bottom of the outer ring (12) and the point of contact between a ball (13) and the outer ring (12), as well as being separated from a contact ellipse between the ball (13) and an outer ring track groove (12a) ## Claims ### Claim 1 A ball bearing comprising: an inner ring having an inner ring raceway groove formed in an outer peripheral surface; an outer ring having an outer ring raceway groove formed in an inner peripheral surface, a counterbore formed at one axial side of the outer ring raceway groove, and a groove shoulder formed at the other axial side of the outer ring raceway groove; and a plurality of balls arranged rollably between the inner ring raceway groove and the outer ring raceway groove, wherein the ball bearing is lubricated by lubricating oil, wherein the outer ring has at least one radial hole penetrating from an outer peripheral surface thereof to the inner peripheral surface thereof in a radial direction, and wherein an axial position of an inner diameter-side opening of the radial hole is located between a groove bottom of the outer ring and a contact point of the ball and the outer ring and is spaced from a contact ellipse between the ball and the outer ring raceway groove. ### Claim 2 A ball bearing comprising: an inner ring having an inner ring raceway groove formed in an outer peripheral surface; an outer ring having an outer ring raceway groove formed in an inner peripheral surface, a counterbore formed at one axial side of the outer ring raceway groove, and a groove shoulder formed at the other axial side of the outer ring raceway groove; and a plurality of balls arranged rollably between the inner ring raceway groove and the outer ring raceway groove, wherein the ball bearing is lubricated by lubricating oil, wherein the outer ring has at least one radial hole penetrating from an outer peripheral surface thereof to the inner peripheral surface thereof in a radial direction, and wherein an axial position of an inner diameter-side opening of the radial hole is located in the outer ring raceway groove at an opposite side to a groove bottom of the outer ring with respect to a contact point of the ball and the outer ring and is spaced from a contact ellipse between the ball and the outer ring raceway groove. ### Claim 3 A ball bearing comprising: an inner ring having an inner ring raceway groove formed in an outer peripheral surface; an outer ring having an outer ring raceway groove formed in an inner peripheral surface, a counterbore formed at one axial side of the outer ring raceway groove, and a groove shoulder formed at the other axial side of the outer ring raceway groove; and a plurality of balls arranged rollably between the inner ring raceway groove and the outer ring raceway groove, wherein the ball bearing is lubricated by lubricating oil, wherein the outer ring has at least one radial hole penetrating from an outer peripheral surface thereof to the inner peripheral surface thereof in a radial direction, and wherein an axial position of an inner diameter-side opening of the radial hole is spaced from a contact ellipse between the ball and the outer ring raceway groove and is provided over the outer ring raceway groove and the groove shoulder at an opposite side to a groove bottom of the outer ring with respect to a contact point of the ball and the outer ring. ### Claim 4 A ball bearing comprising: an inner ring having an inner ring raceway groove formed in an outer peripheral surface; an outer ring having an outer ring raceway groove formed in an inner peripheral surface, a counterbore formed at one axial side of the outer ring raceway groove, and a groove shoulder formed at the other axial side of the outer ring raceway groove; and a plurality of balls arranged rollably between the inner ring raceway groove and the outer ring raceway groove, wherein the ball bearing is lubricated by lubricating oil, wherein the outer ring has at least one radial hole penetrating from an outer peripheral surface thereof to the inner peripheral surface thereof in a radial direction, wherein an axial position of an inner diameter-side opening of the radial hole is provided in the groove shoulder, and wherein at least a part of the inner diameter-side opening of the radial hole axially overlaps the ball. ### Claim 5 (depends on 1) The ball bearing according to claim 1, wherein the outer peripheral surface of the outer ring is formed with a concave groove which is formed along a circumferential direction and which is configured to communicate with the radial hole. ### Claim 6 (depends on 5) The ball bearing according to claim 5, wherein the outer peripheral surface of the outer ring is formed with annular grooves which is formed along the circumferential direction and which is formed at both axial sides with the concave groove being interposed therebetween, and wherein an annular seal member is arranged in each of the annular grooves. ### Claim 7 (depends on 1) The ball bearing according to claim 1, wherein a diameter of the radial hole is 0.5 to 1.5 mm. ### Claim 8 (depends on 1) The ball bearing according to claim 1, wherein a contact angle of the ball is within a range of 25 to 60°. ### Claim 9 (depends on 1) A spindle device comprising: the ball bearing according to claim 1; a cylindrical roller bearing arranged at a side of the ball bearing; and a housing to which the outer ring of the ball bearing and an outer ring of the cylindrical roller bearing are internally fitted, wherein a radial gap Δ between the outer peripheral surface of the outer ring of the ball bearing and an inner peripheral surface of the housing to which the outer ring of the ball bearing is internally fitted is 0.01 to 1 mm measured by a radius measuring method. ### Claim 10 (depends on 9) A machine tool comprising the spindle device according to claim 9. ### Claim 11 (depends on 2) A spindle device comprising: the ball bearing according to claim 2; a cylindrical roller bearing arranged at a side of the ball bearing; and a housing to which the outer ring of the ball bearing and an outer ring of the cylindrical roller bearing are internally fitted, wherein a radial gap Δ between the outer peripheral surface of the outer ring of the ball bearing and an inner peripheral surface of the housing to which the outer ring of the ball bearing is internally fitted is 0.01 to 1 mm measured by a radius measuring method. ### Claim 12 (depends on 3) A spindle device comprising: the ball bearing according to claim 3; a cylindrical roller bearing arranged at a side of the ball bearing; and a housing to which the outer ring of the ball bearing and an outer ring of the cylindrical roller bearing are internally fitted, wherein a radial gap Δ between the outer peripheral surface of the outer ring of the ball bearing and an inner peripheral surface of the housing to which the outer ring of the ball bearing is internally fitted is 0.01 to 1 mm measured by a radius measuring method. ### Claim 13 (depends on 4) A spindle device comprising: the ball bearing according to claim 4; a cylindrical roller bearing arranged at a side of the ball bearing; and a housing to which the outer ring of the ball bearing and an outer ring of the cylindrical roller bearing are internally fitted, wherein a radial gap Δ between the outer peripheral surface of the outer ring of the ball bearing and an inner peripheral surface of the housing to which the outer ring of the ball bearing is internally fitted is 0.01 to 1 mm measured by a radius measuring method.