# US 2014/0154120 A1 · Internal gear pump > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0154120 A1 - Document ID: US20140154120A1 - Status: Published application - Kind: A1 - Application number: 14/088,229 - Filed: 2013-11-22 - Published: 2014-06-05 - Earliest claimed: 2012-11-30 - Assignees: Yamada Manufacturing Co., Ltd. - Applicants: Yamada Manufacturing Co., Ltd - Inventors: Masato Izutsu; Takatoshi Watanabe; Junichi Miyajima; Yasuhiro Kosugi; Kosuke Yamane - Web page: https://patentgrep.com/patent/US20140154120A1 ## CPC - F04C 14/223: {using a movable cam} - 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 14/10: characterised by changing the positions of the inlet or outlet openings with respect to the working chamber - F04C 14/226: {by pivoting the cam around an eccentric axis} - F04C: ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS (engines F03C); ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS ## Abstract The internal gear pump according to the present invention includes: an inner rotor; an outer rotor that rotates with predetermined eccentricity to a rotation center of the inner rotor; an outer ring that rotatably holds the outer rotor, and has at least three cam protruded parts formed; a pump housing that has a rotor chamber; pins in the same number as that of the cam protruded parts; and operation means for oscillating the outer ring. Positions of the pins are set so that a diameter center of the holding-inner peripheral part of the outer ring is moved by the operation means along a locus of a circle, the radius of which is the eccentricity to the rotation center of the inner rotor. ## Claims ### Claim 1 An internal gear pump comprising: an inner rotor; an outer rotor that rotates with predetermined eccentricity to a rotation center of the inner rotor; an outer ring that includes a holding-inner peripheral part rotatably holding the outer rotor and that has at least three cam protruded parts formed along a circumferential direction of an outer periphery surface of the outer ring; a pump housing that has a rotor chamber in which the outer ring is freely and oscillatably arranged; pins that are in the same number as that of the cam protruded parts and are always brought into contact with the cam protruded parts, and that are installed in the rotor chamber as members separate from the pump housing; and operation means for oscillating the outer ring, wherein positions of the pins are set so that a diameter center of the holding-inner peripheral part of the outer ring is moved by the operation means along a locus of a circle, the radius of which is the eccentricity to the rotation center of the inner rotor. ### Claim 2 (depends on 1) The internal gear pump according to claim 1, wherein in contacting and sliding between the pins and the cam protruded parts, the pins are brought into point contact with the cam protruded parts at the same portions thereof. ### Claim 3 (depends on 1) The internal gear pump according to claim 1, wherein the pins are formed in an arc shape at portions that are brought into contact with the cam protruded parts. ### Claim 4 (depends on 1) The internal gear pump according to claim 1, wherein the pins are formed in a circular cylindrical shape. ### Claim 5 (depends on 1) The internal gear pump according to claim 1, wherein the pins are formed of iron alloy. ### Claim 6 (depends on 1) The internal gear pump according to claim 1, wherein a space is provided between the pins and the inner periphery side surface of the rotor chamber. ### Claim 7 (depends on 1) The internal gear pump according to claim 1, wherein stopper wall surface parts with which the cam protruded parts are brought into contact are formed to regulate an oscillation angle of the outer ring to within a predetermined range. ### Claim 8 (depends on 1) The internal gear pump according to claim 1, wherein in contacting and sliding between the pins and the cam protruded parts, the pins are brought into point contact with the cam protruded parts while turning. ### Claim 9 (depends on 8) The internal gear pump according to claim 8, wherein the pins are turnably installed in the rotor chamber. ### Claim 10 (depends on 8) The internal gear pump according to claim 8, wherein the pins are configured by supporting pillar parts and collar parts, and the collar parts are formed in a cylindrical shape and are turnably installed on the supporting pillar parts. ### Claim 11 (depends on 8) The internal gear pump according to claim 8, wherein the pins are configured by supporting pillar parts and collar parts, and the collar parts are configured as ball bearings. ### Claim 12 (depends on 2) The internal gear pump according to claim 2, wherein the pins are formed in an arc shape at portions that are brought into contact with the cam protruded parts. ### Claim 13 (depends on 2) The internal gear pump according to claim 2, wherein the pins are formed in a circular cylindrical shape. ### Claim 14 (depends on 3) The internal gear pump according to claim 3, wherein the pins are formed in a circular cylindrical shape. ### Claim 15 (depends on 2) The internal gear pump according to claim 2, wherein the pins are formed of iron alloy. ### Claim 16 (depends on 3) The internal gear pump according to claim 3, wherein the pins are formed of iron alloy. ### Claim 17 (depends on 2) The internal gear pump according to claim 2, wherein a space is provided between the pins and the inner periphery side surface of the rotor chamber. ### Claim 18 (depends on 3) The internal gear pump according to claim 3, wherein a space is provided between the pins and the inner periphery side surface of the rotor chamber. ### Claim 19 (depends on 2) The internal gear pump according to claim 2, wherein stopper wall surface parts with which the cam protruded parts are brought into contact are formed to regulate an oscillation angle of the outer ring to within a predetermined range. ### Claim 20 (depends on 3) The internal gear pump according to claim 3, wherein stopper wall surface parts with which the cam protruded parts are brought into contact are formed to regulate an oscillation angle of the outer ring to within a predetermined range.