# US 9,039,397 B2 · Rotor for oil pump with different contours for the drive-side versus non-drive side of the teeth > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,039,397 B2 - Document ID: US9039397B2 - Status: Granted - Kind: B2 - Application number: 13/903,877 - Filed: 2013-05-28 - Published: 2013-12-05 - Granted: 2015-05-26 - Earliest claimed: 2012-06-01 - Assignees: Yamada Manufacturing Co., Ltd. - Applicants: Yamada Manufacturing Co., Ltd - Inventors: Kenichi Fujiki; Masato Izutsu; Takatoshi Watanabe - Web page: https://patentgrep.com/patent/US9039397B2 ## CPC - F04C 2/10: of internal-axis type with the outer member having more teeth or tooth-equivalents, e.g. rollers, than the inner member - F04C 2/084: {Toothed wheels} - F04C 2/102: {the two members rotating simultaneously around their respective axes} - F04C: ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS (engines F03C); ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS ## Abstract A rotor for an oil pump according to the present invention is a rotor that includes an inner rotor configured by teeth, each of which has a plurality of ellipses or circles, and an outer rotor that is disposed on the outside of the inner rotor and has one tooth more than the inner rotor, wherein, in a tooth of the inner rotor, a tooth top and a tooth root of a drive-side half-tooth region extending from the tooth top to the tooth root and a tooth top and a tooth root of a non-drive-side half-tooth region extending from the tooth top to the tooth root are each configured by a different ellipse or a circle. A circumferential axis along a circumferential direction of the ellipse or circle configuring the tooth top is longer in the non-drive-side half-tooth region than in the drive-side half-tooth region. ## Claims ### Claim 1 A rotor for an oil pump, comprising: an inner rotor part having a plurality of inner rotor teeth, each of which has a plurality of ellipses or circles; and an outer rotor part that is disposed on an outside of the inner rotor part, the outer rotor part having a plurality of outer rotor teeth, and has one outer rotor tooth more than the inner rotor part, wherein, in an inner rotor tooth of the plurality of inner rotor teeth, a tooth top and a tooth root of a drive-side half-tooth region extending from the tooth top to the tooth root and a tooth top and a tooth root of a non-drive-side half-tooth region extending from the tooth top to the tooth root are each configured by a different ellipse or a circle, and a circumferential axis along a circumferential direction of the ellipse or circle configuring the tooth top is longer in the non-drive-side half-tooth region than in the drive-side half-tooth region, and wherein a top of the tooth of the inner rotor part is in a shape of an ellipse, a root of the tooth in the non-drive-side half-tooth region of the inner rotor part is in a shape of an ellipse, and the teeth of the outer rotor part are each formed of an envelope that is formed when the teeth of the inner rotor part rotate. ### Claim 2 (depends on 1) The rotor for an oil pump according to claim 1, wherein a circumferential axis along a circumferential direction of the ellipse or circle configuring the tooth root is longer in the non-drive-side half-tooth region than in the drive-side half-tooth region. ### Claim 3 (depends on 1) The rotor according to claim 1, wherein the plurality of inner rotor teeth are each asymmetric. ### Claim 4 (depends on 1) The rotor according to claim 1, wherein the drive-side half-tooth region and the non-drive-side half-tooth region have an asymmetrical shape. ### Claim 5 (depends on 1) The rotor according to claim 1, wherein the non-drive-side half-tooth region is larger than the drive-side half-tooth region. ### Claim 6 (depends on 1) The rotor according to claim 1, wherein a difference in a radial height between the tooth top and the tooth root is common between the drive-side half-tooth region and the non-drive-side half-tooth region. ### Claim 7 A rotor for an oil pump, comprising: an inner rotor part having a plurality of inner rotor teeth, each of which has a plurality ellipses or circles; and an outer rotor part that is disposed on the outside of the inner rotor part, the outer rotor part having a plurality of outer rotor teeth, and has one outer rotor tooth more than the inner rotor part, wherein, in a tooth of the inner rotor part, a tooth top and a tooth root of a drive-side half-tooth region extending from the tooth top to the tooth root and a tooth top and a tooth root of a non-drive-side half-tooth region extending from the tooth top to the tooth root are each configured by a different ellipse or a circle, and a sum of the length of a circumferential axis along a circumferential direction of the ellipse or circle configuring the tooth top and the length of a circumferential axis along a circumferential direction of the ellipse or circle configuring the tooth root is greater in the non-drive-side half-tooth region than in the drive-side half-tooth region, and wherein a top of the tooth of the inner rotor part is in a shape of an ellipse, a root of the tooth in the non-drive-side half-tooth region of the inner rotor part is in a shape of an ellipse, and the teeth of the outer rotor part are each formed of an envelope that is formed when the teeth of the inner rotor part rotate. ### Claim 8 (depends on 7) The rotor according to claim 7, wherein the plurality of inner rotor teeth are each asymmetric. ### Claim 9 (depends on 7) The rotor according to claim 7, wherein the drive-side half-tooth region and the non-drive-side half-tooth region have an asymmetrical shape. ### Claim 10 (depends on 7) The rotor according to claim 7, wherein the non-drive-side half-tooth region is larger than the drive-side half-tooth region. ### Claim 11 (depends on 7) The rotor according to claim 7, wherein a difference in a radial height between the tooth top and the tooth root is common between the drive-side half-tooth region and the non-drive-side half-tooth region. ### Claim 12 An oil pump, comprising: a rotor including: an inner rotor part having a plurality of inner rotor teeth, each of which has a plurality of ellipses; and an outer rotor part that is disposed on an outside of the inner rotor part, the outer rotor part having a plurality of outer rotor teeth, and has one outer rotor tooth more than the inner rotor part, wherein, in an inner rotor tooth of the plurality of inner rotor teeth, a tooth top and a tooth root of a drive-side half-tooth region extending from the tooth top to the tooth root and a tooth top and a tooth root of a non-drive-side half-tooth region extending from the tooth top to the tooth root are each configured by a different ellipse, and a circumferential axis along a circumferential direction of the ellipse configuring the tooth top is longer in the non-drive-side half-tooth region than in the drive-side half-tooth region, and wherein a top of the tooth of the inner rotor part is in a shape of an ellipse, a root of the tooth in the non-drive-side half-tooth region of the inner rotor part is in a shape of an ellipse, and the teeth of the outer rotor part are each formed of an envelope that is formed when the teeth of the inner rotor part rotate. ### Claim 13 (depends on 12) The oil pump according to claim 12, wherein the plurality of inner rotor teeth are each asymmetric. ### Claim 14 (depends on 12) The oil pump according to claim 12, wherein the drive-side half-tooth region and the non-drive-side half-tooth region have an asymmetrical shape. ### Claim 15 (depends on 12) The oil pump according to claim 12, wherein the non-drive-side half-tooth region is larger than the drive-side half-tooth region. ### Claim 16 (depends on 12) The oil pump according to claim 12, wherein a difference in a radial height between the tooth top and the tooth root is common between the drive-side half-tooth region and the non-drive-side half-tooth region.