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EP-4360997-B1 - STEERING DEVICE

EP4360997B1EP 4360997 B1EP4360997 B1EP 4360997B1EP-4360997-B1

Inventors

  • KAWAMURA, Naofumi
  • ASAKAWA, Kazuhisa
  • SUZUKI, HIROAKI
  • EBISU, Tetsuya
  • FUJIOKA, YUKI
  • SUGIURA, TOMONORI
  • ITO, KOSUKE
  • BAITO, Takahiro
  • NAKAAKI, TAKAO
  • MURAKAMI, YOSHIAKI

Dates

Publication Date
20260513
Application Date
20220209

Claims (9)

  1. A steering device (1) comprising: a cylindrical support tube that includes a flange (31) and that rotatably supports a steering shaft (2); a speed reducer (20) configured to apply a torque to the steering shaft (2); a housing (18) that includes a cylindrical portion housing the speed reducer (20), the cylindrical portion being disposed coaxially with the flange (31); a bolt (30) that couples the flange (31) and the cylindrical portion to each other; a bearing support member (50) that is fitted to an inner peripheral surface of the cylindrical portion and through which the steering shaft (2) extends; and a bearing (71) interposed between an outer peripheral surface of the steering shaft (2) and an inner peripheral surface of the bearing support member (50), wherein the bearing support member (50) includes a wall portion extending in the radial direction, and a deformation allowing portion configured to allow elastic deformation of the bearing support member (50) in the radial direction, the deformation allowing portion includes a first slit (55) provided in the wall portion, and the first slit (55) is an annular groove extending continuously in a circumferential direction along an outer peripheral surface of the bearing support member (50), characterized in that the deformation allowing portion further includes a second slit (56) provided in the wall portion, and the second slit (56) is an annular groove positioned on a radially inner side with respect to the first slit (55) and extending continuously in the circumferential direction along the inner peripheral surface of the bearing support member (50).
  2. The steering device (1) according to claim 1, wherein: the bearing support member (50) includes a peripheral wall (50A), and the wall portion is an end wall (50B) extending radially inward from an end of the peripheral wall (50A) in an axial direction; the end wall (50B) includes a first end face and a second end face positioned opposite to each other in the axial direction; and the first slit (55) and the second slit (56) are provided on one same end face out of the first end face and the second end face, or are provided on different end faces out of the first end face and the second end face.
  3. The steering device (1) according to claim 2, wherein: the first end face includes the first slit (55) and the second slit (56); and the second end face includes: a plurality of recesses (57) provided away from each other in the circumferential direction in a region of the second end face between the first slit (55) and the second slit (56); and a plurality of ribs (58) that is parts of the bearing support member (50) between the two recesses (57) adjacent in the circumferential direction.
  4. The steering device (1) according to any one of claims 1 to 3, wherein the bearing support member (50) and the cylindrical portion include engagement portions that engage with each other in an axial direction of the bearing support member (50).
  5. The steering device (1) according to claim 4, wherein: the engagement portions include an outward protruding thread (53) extending in the circumferential direction along the outer peripheral surface of the bearing support member (50), and a groove (46) extending in the circumferential direction along the inner peripheral surface of the cylindrical portion; and the outward protruding thread (53) engages with the groove (46) in the axial direction of the bearing support member (50).
  6. The steering device (1) according to claim 4 or 5, wherein: the bearing support member (50) includes a peripheral wall (50A), an end wall (50B) extending radially inward from an end of the peripheral wall (50A) in the axial direction, and a corner (54) formed at a part where the peripheral wall (50A) and the end wall (50B) intersect each other; the engagement portions include a stepped portion (45) extending in the circumferential direction along the inner peripheral surface of the cylindrical portion, and the corner (54) of the bearing support member (50); and the corner (54) engages with the stepped portion (45) in the axial direction of the bearing support member (50).
  7. The steering device (1) according to any one of claims 1 to 6, wherein: the bearing support member (50) includes an inward protruding thread (52) extending in the circumferential direction along the inner peripheral surface of the bearing support member (50); and the inward protruding thread (52) engages with the bearing (71) in an axial direction of the bearing support member (50).
  8. The steering device (1) according to any one of claims 1 to 7, wherein the bearing support member (50) and the housing (18) have different linear thermal expansion coefficients.
  9. The steering device (1) according to any one of claims 1 to 8, wherein: the speed reducer (20) includes a worm wheel (22) configured to rotate together with the steering shaft (2), and a worm (21) that meshes with the worm wheel (22); the housing (18) includes a worm wheel housing member (41) housing the worm wheel (22), and a worm housing member (42) housing the worm (21); and the cylindrical portion is the worm wheel housing member (41).

Description

TECHNICAL FIELD The present disclosure relates to a steering device. BACKGROUND ART Hitherto, there is an electric power steering system using a motor to assist steering. For example, a steering device of JP 2020-90 139 A includes a motor and a metal housing. The housing houses a torque sensor and a worm gear mechanism. The motor generates a torque based on a steering torque detected by the torque sensor. The torque of the motor is transmitted to a steering shaft via the worm gear mechanism. The housing includes a worm housing member and a sensor housing member. The worm housing member houses the worm gear mechanism. The sensor housing member houses the torque sensor. The worm housing member and the sensor housing member are fitted together in an axial direction of the steering shaft. The steering shaft is supported via bearings so as to be rotatable relative to the worm housing member and the sensor housing member. EP 2 921 372 A1 discloses a steering device according to the preamble of claim 1. SUMMARY OF THE INVENTION Problem to be Solved by the Invention In recent years, customer demands for steering devices have become increasingly diverse based on vehicle specifications and other factors. In order to meet these demands, a wide range of research and development has been conducted on the configurations of steering devices. A steering device having a new configuration may be required. Means for Solving the Problem A steering device according to an aspect of the present disclosure includes a cylindrical support tube that includes a flange and that rotatably supports a steering shaft, a speed reducer configured to apply a torque to the steering shaft, a housing that includes a cylindrical portion housing the speed reducer, the cylindrical portion being disposed coaxially with the flange, a bolt that couples the flange and the cylindrical portion to each other, a bearing support member that is fitted to an inner peripheral surface of the cylindrical portion and through which the steering shaft extends, and a bearing interposed between an outer peripheral surface of the steering shaft and an inner peripheral surface of the bearing support member. The bearing support member includes a deformation allowing portion configured to allow elastic deformation of the bearing support member in a radial direction. BRIEF DESCRIPTION OF THE DRAWINGS [FIG. 1] FIG. 1 is a schematic diagram showing the configuration of a steering device according to an embodiment.[FIG. 2] FIG. 2 is a perspective view of a steering column in FIG. 1.[FIG. 3] FIG. 3 is a sectional view of a coupling portion between a housing and a lower tube in FIG. 2.[FIG. 4] FIG. 4 is a perspective view of a bearing support member in FIG. 3 that is viewed diagonally from the top.[FIG. 5] FIG. 5 is a perspective view of the bearing support member in FIG. 3 that is viewed diagonally from the bottom.[FIG. 6] FIG. 6 is a sectional perspective view of the bearing support member in FIG. 3.[FIG. 7] FIG. 7 is a sectional perspective view of the bearing support member in FIG. 3.[FIG. 8] FIG. 8 is a sectional view of the bearing support member in FIG. 3.[FIG. 9] FIG. 9 is a sectional view of a bearing support member according to another embodiment.[FIG. 10] FIG. 10 is a sectional view of a bearing support member according to another embodiment. MODES FOR CARRYING OUT THE INVENTION A steering device according to an embodiment will be described. As shown in FIG. 1, a steering device 1 includes a steering shaft 2, an intermediate shaft 3, a pinion shaft 4, and a rack shaft 5. A steering wheel 6 is coupled to a first end of the steering shaft 2. A first end of the intermediate shaft 3 is coupled to a second end of the steering shaft 2 via a universal joint 7. A first end of the pinion shaft 4 is coupled to a second end of the intermediate shaft 3 via a universal joint 8. A pinion 4a is provided at a second end of the pinion shaft 4. The pinion 4a meshes with a rack 5a provided on the rack shaft 5. The rack shaft 5 is supported inside a housing 10 fixed to a frame 9 of a vehicle body. The rack shaft 5 is movable in a right direction or a left direction with respect to a direction of travel of a vehicle. Both ends of the rack shaft 5 are coupled to right and left steered wheels (not shown) via tie rods (not shown). The steering shaft 2 includes an outer shaft 11 and an inner shaft 12. The outer shaft 11 and the inner shaft 12 are coupled to each other by, for example, spline coupling. The outer shaft 11 and the inner shaft 12 can rotate together and can move relatively in their axial direction. The steering shaft 2 is disposed so as to be inclined with respect to a front-rear direction of the vehicle with the steering wheel 6 facing upward. The steering device 1 includes a steering column 15. The steering shaft 2 is inserted through the steering column 15. The steering shaft 2 is supported via a bearing (not shown) so as to be rotatable relative to the steering column 15. T