# US 12,005,971 B2 · Rack assist type power steering apparatus > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,005,971 B2 - Document ID: US12005971B2 - Status: Granted - Kind: B2 - Application number: 18/052,869 - Filed: 2022-11-04 - Published: 2023-05-25 - Granted: 2024-06-11 - Earliest claimed: 2021-11-19 - Assignees: Hl Mando Corporation - Applicants: Hl Mando Corporation - Inventors: InHwan Jeon - Web page: https://patentgrep.com/patent/US12005971B2 ## CPC - B62D 5/0448: {Ball nuts} - B62D 5/0403: {characterised by constructional features, e.g. common housing for motor and gear box} - B62D 5/0421: {Electric motor acting on or near steering gear} - B62D 5/0424: {the axes of motor and final driven element of steering gear, e.g. rack, being parallel} - B62D 3/12: of rack-and-pinion type - B62D: MOTOR VEHICLES; TRAILERS (steering, or guiding on a desired track, of agricultural machines or implements A01B69/00; wheels, castors, axles, increasing wheel adhesion B60B; vehicle tyres, tyre inflation or tyre changing B60C; connections between vehicles of a train or the like B60D; vehicles for use on rail and road, amphibious or convertible vehicles B60F; suspension arrangements B60G; heating, cooling, ventilating or other air treating devices B60H; windows, windscreens, non-fixed roofs, doors or similar devices, protective coverings for vehicles not in use B60J; propulsion plant arrangements, auxiliary drives, transmissions, controls, instrumentation or dashboards B60K; electric equipment or propulsion of electrically-propelled vehicles B60L; power supply for electrically-propelled vehicles B60M; passenger accommodation not otherwise provided for B60N; adaptations for load transportation or to carry special loads or objects B60P; arrangement of signalling or lighting devices, the mounting or supporting thereof or circuits therefor, for vehicles in general B60Q; vehicles, vehicle fittings or vehicle parts not otherwise provided for B60R; servicing, cleaning, repairing, supporting, lifting, or manoeuvring, not otherwise provided for, B60S; brake arrangements, brake control systems or parts thereof B60T; air-cushion vehicles B60V; motor-cycles, accessories therefor B62J, B62K; testing of vehicles G01M) ## Abstract A rack assist type power steering apparatus according to the embodiments of the present disclosure comprises a rack bar provided with an outer screw groove on an outer circumferential surface, a ball nut having an inner screw groove corresponding to the outer screw groove on an inner circumferential surface, and a bearing coupled to an outer circumferential surface, and a nut pulley provided with a belt coupling portion on an outer peripheral surface, and one end of an inner circumferential surface is provided with a support end coupled to an outer circumferential surface of the ball nut to support the bearing, and an other end of an inner circumferential surface is provided with an enlarged diameter portion which is stepped from the support end and increases in inner diameter. ## Claims ### Claim 1 A rack assist type power steering apparatus comprising: a rack bar provided with an outer screw groove on an outer circumferential surface; a ball nut having an inner screw groove corresponding to the outer screw groove on an inner circumferential surface, and a bearing coupled to an outer circumferential surface; and a nut pulley provided with a belt coupling portion on an outer peripheral surface, and one end of an inner circumferential surface is provided with a support end coupled to an outer circumferential surface of the ball nut to support the bearing in an axial direction, and an opposite end of an inner circumferential surface is provided with an enlarged diameter portion which is stepped from the support end and increases in inner diameter, wherein a support protrusion is formed by protruding from the outer circumferential surface of the ball nut in a location where the support protrusion is in contact with one end of an inner race of the bearing such that the support protrusion supports the one end of the inner race of the bearing in an opposite axial direction. ### Claim 2 (depends on 1) The rack assist type power steering apparatus of claim 1, wherein a pulley screw portion is formed on an inner circumferential surface of the support end and a nut screw portion is formed on an outer circumferential surface of the ball nut, so that the pulley screw portion is screwed with the nut screw portion. ### Claim 3 (depends on 2) The rack assist type power steering apparatus of claim 2, wherein a fixing groove is formed on an outer circumferential surface of the ball nut to which the nut pulley is coupled, and is caulked and fixed to an end of the support end of the nut pulley. ### Claim 4 (depends on 3) The rack assist type power steering apparatus of claim 3, wherein the fixing groove is one or more, and when two or more are provided, they are arranged at equal intervals in a circumferential direction of the ball nut. ### Claim 5 (depends on 2) The rack assist type power steering apparatus of claim 2, wherein the support end is formed to protrude in the axial direction with a step difference in a radial direction from the belt coupling portion to support an opposite end of the inner race of the bearing in the axial direction. ### Claim 6 (depends on 5) The rack assist type power steering apparatus of claim 5, wherein a tool coupling portion to which a tool is coupled is formed on an outer circumferential surface of the support end. ### Claim 7 (depends on 2) The rack assist type power steering apparatus of claim 2, wherein a fastening groove formed in a circumferential direction is provided on an outer peripheral surface of the ball nut to which the nut pulley is coupled, and a fastening member is coupled to the fastening groove. ### Claim 8 (depends on 7) The rack assist type power steering apparatus of claim 7, wherein the fastening member is formed in a ring shape with one side cut off and is supported at an end of the support end. ### Claim 9 (depends on 1) The rack assist type power steering apparatus of claim 1, wherein an inner circumferential surface of the support end of the nut pulley is press-fitted to the outer circumferential surface of the ball nut and coupled thereto. ### Claim 10 (depends on 9) The rack assist type power steering apparatus of claim 9, wherein a fixing groove is formed on an outer circumferential surface of the ball nut to which the nut pulley is coupled, and is caulked and fixed to an end of the support end of the nut pulley. ### Claim 11 (depends on 10) The rack assist type power steering apparatus of claim 10, wherein the fixing groove is one or more, and when two or more are provided, they are arranged at equal intervals in the circumferential direction of the ball nut. ### Claim 12 (depends on 9) The rack assist type power steering apparatus of claim 9, wherein a fastening groove formed in a circumferential direction is provided on an outer peripheral surface of the ball nut to which the nut pulley is coupled, and a fastening member is coupled to the fastening groove. ### Claim 13 (depends on 12) The rack assist type power steering apparatus of claim 12, wherein the fastening member is formed in a ring shape with one side cut off, and the fastening member is coupled to the fastening groove to be supported by an end of the support end. ### Claim 14 (depends on 9) The rack assist type power steering apparatus of claim 9, wherein the support end is formed to protrude in the axial direction with a step difference in a radial direction from the belt coupling portion to support an opposite end of the inner race of the bearing in the axial direction.