# US 12,759,617 B2 · Steering actuator and initial free play adjustment method between reducer gears of steering actuator > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,759,617 B2 - Document ID: US12759617B2 - Status: Granted - Kind: B2 - Application number: 18/211,186 - Filed: 2023-06-16 - Published: 2023-12-21 - Granted: 2026-10-13 - Earliest claimed: 2022-06-17 - Assignees: Hl Mando Corporation - Applicants: Hl Mando Corporation - Inventors: Seongmoo Heo - Web page: https://patentgrep.com/patent/US12759617B2 ## CPC - B62D 5/0421: {Electric motor acting on or near steering gear} - B62D 7/16: Arrangement of linkage connections (pivots per se F16C) - F16H 37/122: {for interconverting rotary motion and oscillating motion} - F16H 57/021: Shaft support structures, e.g. partition walls, bearing eyes, casing walls or covers with bearings - F16H 57/023: Mounting or installation of gears or shafts in the gearboxes, e.g. methods or means for assembly - F16H 57/039: Gearboxes for accommodating worm gears - F16H 57/12: Arrangements for adjusting or for taking-up backlash not provided for elsewhere - F16H 2057/02034: {Gearboxes combined or connected with electric machines} - F16H 2057/02082: {for application in vehicles other than propelling, e.g. adjustment of parts} - F16H 2057/125: {Adjustment of backlash during mounting or assembly of gearing} - 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) - F16H: GEARING ## Abstract Disclosed herein is a steer-by-wire type steering actuator. In accordance with one aspect of the present disclosure, a steering actuator may include: a first reducer including a worm configured to rotate by receiving a rotational force of a motor and a worm wheel configured to rotate in engagement with the worm; a pinion shaft coupled to a center of the worm wheel and configured to rotate together with the worm wheel; a second reducer including a first gear formed on the pinion shaft, and an output shaft configured to operate a pitman arm while rotating by receiving a rotational force through a second gear engaged with the first gear; a first gear housing configured to receive the worm and coupled to the motor; a second gear housing provided with a first mounter for receiving and mounting the pinion shaft and a second mounter formed apart to communicate with the first mounter and configured to receive and mount the output shaft, and coupled to the first gear housing; and a holder configured to rotatably support the pinion shaft and having a rotational center axis eccentric with respect to a central axis of the pinion shaft to adjust an axial distance between the pinion shaft and the output shaft. ## Claims ### Claim 1 A steering actuator comprising: a first reducer including a worm configured to rotate by receiving a rotational force of a motor and a worm wheel configured to rotate in engagement with the worm; a pinion shaft coupled to a center of the worm wheel and configured to rotate together with the worm wheel; a second reducer including a first gear formed on the pinion shaft, and an output shaft configured to operate a pitman arm while rotating by receiving a rotational force through a second gear engaged with the first gear; a first gear housing configured to receive the worm and coupled to the motor; a second gear housing provided with a first mounter for receiving and mounting the pinion shaft and a second mounter formed apart to communicate with the first mounter and configured to receive and mount the output shaft, and coupled to the first gear housing; and a holder configured to rotatably support the pinion shaft and having a rotational center axis eccentric with respect to a central axis of the pinion shaft to adjust an axial distance between the pinion shaft and the output shaft, wherein the first mounter of the second gear housing has free play adjustment protrusions that are spaced a predetermined distance apart from each other and have a predetermined length, the first gear housing has a free play adjustment groove, into which each of the free play adjustment protrusions is inserted, in a position corresponding to each of the free play adjustment protrusions, and the free play adjustment groove has a greater length than the free play adjustment protrusion. ### Claim 2 (depends on 1) The steering actuator of claim 1, wherein the holder further comprises an upper bearing coupled to the pinion shaft and assembled at an upper side of the holder and a lower bearing coupled to the pinion shaft and assembled at a lower side of the holder. ### Claim 3 (depends on 2) The steering actuator of claim 2, further comprising a fixing device configured to restrict an axial movement of the pinion shaft and fix the upper bearing and the lower bearing to the holder. ### Claim 4 (depends on 3) The steering actuator of claim 3, wherein the fixing device comprises: a wave washer disposed above the upper bearing; a lock ring disposed below the lower bearing and stacking-assembled with the pinion shaft to support an inner ring of the lower bearing; and a flange formed to extend from the pinion shaft in a radial direction and configured to apply a pressure to support an inner ring of the upper bearing through the wave washer. ### Claim 5 (depends on 4) The steering actuator of claim 4, wherein the wave washer is elastically deformed by being pressed by the flange and absorbs tolerance. ### Claim 6 (depends on 2) The steering actuator of claim 2, wherein the holder comprises an upper holder having an upper assembly groove in which the upper bearing is assembled and a lower holder having a lower assembly groove in which the lower bearing is assembled, and the upper assembly groove and the lower assembly groove are formed in a row so as to have the same central axis as the pinion shaft. ### Claim 7 (depends on 6) The steering actuator of claim 6, wherein a stopper configured to support an outer ring of the upper bearing and an outer ring of the lower bearing is provided between the upper assembly groove and the lower assembly groove. ### Claim 8 (depends on 6) The steering actuator of claim 6, wherein the lower holder is formed to have a central axis eccentric with respect to the central axis of the pinion shaft so that a position of the central axis of the pinion shaft is changed according to rotation of the lower holder. ### Claim 9 (depends on 6) The steering actuator of claim 6, wherein the first mounter has a seating jaw protruding upward to form a seating groove where the lower holder is seated, and the upper holder is seated on an upper surface of the seating jaw and supported. ### Claim 10 (depends on 9) The steering actuator of claim 9, wherein a plurality of coupling pieces, which are spaced a predetermined distance apart and protrude in a radial direction are provided at an edge of the upper holder, and the second gear housing is provided with a free play adjustment protrusion with a fastening hole formed in a position corresponding to each of the plurality of coupling pieces. ### Claim 11 (depends on 10) The steering actuator of claim 10, wherein, in the plurality of coupling pieces, a coupling hole is formed so that a bolt passes through to be fastened to the fastening hole, and the coupling hole is provided as a long hole having a predetermined length in a direction corresponding to a circumferential direction of the lower holder. ### Claim 12 (depends on 11) The steering actuator of claim 11, wherein the upper holder is bolted to the free play adjustment protrusion through the long hole and the fastening hole after a backlash between the first gear of the pinion shaft and the second gear of the output shaft is adjusted. ### Claim 13 (depends on 1) The steering actuator of claim 1, wherein the free play adjustment protrusion and the free play adjustment groove are formed to have a predetermined length in a direction where the worm and the worm wheel face each other, and the first gear housing is moved through the free play adjustment groove and the free play adjustment protrusion and fixed to the second gear housing by a bolt after backlash adjustment between the worm and the worm wheel. ### Claim 14 (depends on 1) The steering actuator of claim 1, further comprising a fixing member configured to fix the output shaft to the second mounter. ### Claim 15 (depends on 14) The steering actuator of claim 14, wherein the fixing member comprises: a first fixer assembled with an upper portion of the output shaft with respect to the second gear and rotatably supporting the output shaft; and a second fixer assembled with a lower portion of the output shaft with respect to the second gear and rotatably supporting the output shaft. ### Claim 16 (depends on 15) The steering actuator of claim 15, wherein the first fixer comprises: a needle bearing coupled to an upper end of the output shaft; and a bearing cover having the needle bearing installed at a center and press-fitted to the second mounter. ### Claim 17 (depends on 15) The steering actuator of claim 15, wherein the second fixer comprises: a fixed bearing having an inner ring supported on a stepped portion of the output shaft and an outer ring supported on a mounting hole of the second gear housing; a lock nut screwed to the output shaft to support the inner ring of the fixed bearing; a plug having an inner side receiving the lock nut and an outer side screwed to the mounting hole of the second gear housing; and a dust seal interposed between the inner side of the plug and the output shaft. ### Claim 18 An initial free play adjustment method between reducer gears of a steering actuator, wherein the steering actuator comprises: a first gear housing configured to receive a worm and cover a worm wheel engaged with the worm; a second gear housing in which the worm wheel is disposed and mounted; a plurality of free play adjustment protrusions provided in the second gear housing to be located radially outside the worm wheel; and a free play adjustment groove provided in the first gear housing at a position corresponding to each of the free play adjustment protrusions so that each of the free play adjustment protrusions is inserted, the free play adjustment groove and the free play adjustment protrusion have a predetermined length in a direction where the worm and the worm wheel face each other, and the free play adjustment groove has a greater length than the free play adjustment protrusion, and the steering actuator adjusts a backlash between the worm and the worm wheel by moving the first gear housing in a longitudinal direction of the free play adjustment protrusion and the free play adjustment groove.