# US 2009/0260468 A1 · Steering device and movement converting device used therefor > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2009/0260468 A1 - Document ID: US20090260468A1 - Status: Published application - Kind: A1 - Application number: 12/065,375 - Filed: 2006-08-31 - Published: 2009-10-22 - Earliest claimed: 2005-08-31 - Assignees: Thk Co., Ltd. - Inventors: Yuji Tachikake - Web page: https://patentgrep.com/patent/US20090260468A1 ## CPC - B62D 3/02: mechanical - B62D 5/0421: {Electric motor acting on or near steering gear} - B62D 5/0448: {Ball nuts} - F16H 25/2204: {with balls} - F16H 2025/2093: {using conical gears} - Y10T 74/19749: Recirculating rolling elements - 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 - Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION ## Abstract Provided is a novel steering device which can be formed to be compact, which is easily applicable to a vehicle with a small engine room such as a front-engine/front-drive car, and which is of neither the ball nut type nor the rack and pinion type. The steering device operates steerable wheels by converting rotation of a steering shaft to axial movement of a relay rod, the steering device including: a gear casing through which the relay rod is passed; a spiral ball rolling groove provided in the relay rod within the gear casing so as to exhibit a lead of a magnitude of 1 or more; a nut member threadedly engaged with the ball rolling groove of the relay rod through an intermediation of a large number of balls and supported rotatably with respect to the gear casing; an input shaft to which rotation of the steering shaft is transmitted and which is in an intersecting or offset relationship with the relay rod; and a first transmission gear for transmitting rotation of the input shaft to the nut member. ## Claims ### Claim 1 A steering device for operating steerable wheels by converting rotation of a steering shaft to axial movement of a relay rod, the steering device comprising: a gear casing through which the relay rod is passed; a spiral ball rolling groove provided in the relay rod within the gear casing so as to exhibit a lead of a magnitude of 1 or more; a nut member threadedly engaged with the ball rolling groove of the relay rod through an intermediation of a large number of balls and supported rotatably with respect to the gear casing; an input shaft to which rotation of the steering shaft is transmitted and which is in an intersecting or offset relationship with the relay rod; and a first transmission gear for transmitting rotation of the input shaft to the nut member. ### Claim 2 (depends on 1) A steering device according to claim 1, wherein the first transmission gear exhibits a lower transmission efficiency in transmission from the nut member to the input shaft than in transmission from the input shaft to the nut member. ### Claim 3 (depends on 1) A steering device according to claim 1, wherein the relay rod and the input shaft are in an offset relationship with each other, and wherein the first transmission gear includes a driven-side screw gear provided on an outer peripheral surface of the nut member, and a driving-side screw gear fixed to the input shaft and in mesh with the driven-side screw gear. ### Claim 4 (depends on 3) A steering device according to claim 3, wherein a pair of ball rolling grooves are circumferentially formed in the outer peripheral surface of the nut member with the driven-side screw gear therebetween, and wherein an outer ring of a rotary bearing is attached to the nut member through the intermediation of a large number of balls rolling through the ball rolling grooves. ### Claim 5 (depends on 3) A steering device according to claim 3, wherein the driven-side screw gear has a reference cylinder angle of torsion set to be smaller than that of the driving-side screw gear. ### Claim 6 (depends on 2, 5) A steering device according to claim 2 or 5, wherein the nut member is elastically supported within the gear casing with respect to a rotation axis direction thereof, and is displaceable in the rotation axis direction when an external force is applied thereto. ### Claim 7 (depends on 1) A steering device according to claim 1, further comprising: a torque detection sensor for detecting a magnitude of a rotational torque transmitted between the steering shaft and the input shaft; and an auxiliary motor for aiding rotation of the nut member in response to an output signal from the torque detection sensor. ### Claim 8 (depends on 7) A steering device according to claim 7, wherein the auxiliary motor is provided such that an output shaft thereof is in an intersecting or offset positional relationship with the nut member, and wherein there is provided a second transmission gear for transmitting rotation of the auxiliary motor to the nut member, with a speed reduction ratio of the second transmission gear being set to be 1 or more. ### Claim 9 (depends on 7) A steering device according to claim 7, wherein the first transmission gear includes a driven gear fixed to the nut member and a driving gear fixed to the input shaft and in mesh with the driven gear, and wherein the second transmission gear includes the driven gear and an auxiliary driving gear fixed to the output shaft of the auxiliary motor and in mesh with the driven gear. ### Claim 10 (depends on 9) A steering device according to claim 9, wherein the driven gear, the driving gear, and the auxiliary driving gear are bevel gears. ### Claim 11 (depends on 9) A steering device according to claim 9, wherein the driven gear, the driving gear, and the auxiliary driving gear are screw gears. ### Claim 12 A movement converting device having an input shaft and an output shaft in an intersecting or offset relationship with each other and converting rotational movement of the input shaft to axial linear movement of the output shaft, the movement converting device comprising: a gear casing through which the output shaft is passed; a spiral ball rolling groove provided in the output shaft within the gear casing and formed so as to exhibit a lead of 1 or more; a nut member threadedly engaged with the ball rolling groove of the output shaft through an intermediation of a large number of balls and supported rotatably with respect to the gear casing; and a power transmission gear for transmitting rotation of the input shaft to the nut member, which is in an intersecting or offset relationship with the input shaft.