Steering device

Abstract

The present application relates to a steering device. The steering device has a support cylinder (17) that supports a steering shaft (2), and a housing (18) that has a cylindrical portion (41) that houses a speed reducer (20). A bearing support member (50) is fitted to an inner peripheral surface of the cylindrical portion (41). A bearing (71) is disposed between an outer peripheral surface of the steering shaft (2) and an inner peripheral surface of the bearing support member (50). The bearing support member (50) has an inner peripheral wall (51) that is fitted to an outer peripheral surface of the bearing (71), an outer peripheral wall (52) that is fitted to the inner peripheral surface of the cylindrical portion (41), and a link wall (53) that links the inner peripheral wall (51) and the outer peripheral wall (52) in a radial direction. The inner peripheral wall (51) extends from the link wall (53) in the same direction as a mounting direction (DW), and the outer peripheral wall (52) extends in a direction opposite to the mounting direction (DW).

Description

TECHNICAL FIELD

[0001] The present application relates to a steering device. BACKGROUND

[0002] In the past, there has been an electric power steering device that assists steering operation with a motor. For example, the steering device of Patent Literature 1 has a motor and a bearing unit. A steering shaft penetrates the bearing unit in the axial direction. The bearing unit has a housing. The housing has a housing and a housing cover. The housing has an opening portion that is open in the axial direction. The housing cover is installed to the housing in a manner that plugs the opening portion of the housing.

[0003] The housing houses a bevel gear and a damper disc. The bevel gear is linked to the steering shaft in a manner that can rotate integrally. The bevel gear is driven by the motor. The bevel gear is supported in the axial direction by both a first bearing and a second bearing. The first bearing is provided to the damper disc. The second bearing is provided to an end wall of the housing. The end wall is a wall on the side opposite the opening portion. The steering shaft is supported so as to be rotatable relative to the housing via the first bearing and the second bearing.

[0004] The damper disc is located between the bevel gear and the housing cover in the axial direction. The damper disc is installed to the outer peripheral surface of the steering shaft via the first bearing. The outer peripheral surface of the damper disc is in abutment with the inner peripheral surface of the housing. A portion of the housing cover is supported by the side surface of the damper disc via a spring member. The spring member exerts an elastic force on the damper disc in the axial direction toward the bevel gear. The movement of the damper disc in the direction away from the bevel gear is suppressed by the elastic force of the spring member.

[0005] The damper disc has a function of damping the impact in the radial direction and the axial direction of the steering shaft.

[0006] Patent Literature 1: Japanese Patent Application Laid-Open No. 2018-520926

[0007] In recent years, the requirements of customers for steering devices based on the specifications of vehicles and the like have diversified. In order to cope with the above requirements, various research and development have been conducted throughout the structure of the steering device. Steering devices with new structures are sought. SUMMARY

[0008] The turning device of one embodiment of the present application has a cylindrical support cylinder having a flange and supporting a turning shaft so as to be rotatable, a speed reducer configured to apply a torque to the turning shaft, a housing having a cylindrical portion that houses the speed reducer, the cylindrical portion being connected coaxially with the flange, a bearing support member that is fitted to an inner peripheral surface of the cylindrical portion from a direction along an axial direction, that is, a mounting direction, and through which the turning shaft is passed, and a bearing that is sandwiched between an outer peripheral surface of the turning shaft and an inner peripheral surface of the bearing support member. The bearing support member has an inner peripheral wall that is fitted to an outer peripheral surface of the bearing, an outer peripheral wall that is fitted to the inner peripheral surface of the cylindrical portion, and a connecting wall that connects the inner peripheral wall and the outer peripheral wall in a radial direction. The inner peripheral wall has a base end portion connected to the connecting wall and extends from the connecting wall in the same direction as the mounting direction. The outer peripheral wall has a base end portion connected to the connecting wall and extends from the connecting wall in a direction opposite to the mounting direction. BRIEF DESCRIPTION OF DRAWINGS

[0009] Figure 1 is a schematic view showing the structure of the turning device of the first embodiment.

[0010] Figure 2 is Figure 1 a perspective view of the steering column of

[0011] Figure 3 is Figure 2 a cross-sectional view of the connecting portion of the housing and the lower tube of

[0012] Figure 4 is a perspective view of the bearing support member of Figure 3 from an oblique upper side.

[0013] Figure 5 is a perspective view of the bearing support member of Figure 3 from an oblique lower side.

[0014] Figure 6 is Figure 3 a semi-cross-sectional view of the bearing support member of

[0015] Figure 7 is Figure 3 a semi-cross-sectional view of the bearing support member of

[0016] Figure 8 is a cross-sectional view of the housing of the second embodiment. DETAILED DESCRIPTION

[0017] <First Embodiment>

[0018] The first embodiment of the turning device will be described.

[0019] AsFigure 1 As shown in the figure, the steering device 1 has a steering shaft 2, an intermediate shaft 3, a pinion shaft 4, and a rack shaft 5. A steering wheel 6 is connected to a first end portion of the steering shaft 2. A first end portion of the intermediate shaft 3 is connected to a second end portion of the steering shaft 2 via a universal joint 7. A first end portion of the pinion shaft 4 is connected to a second end portion of the intermediate shaft 3 via a universal joint 8. A pinion 4a is provided to a second end portion of the pinion shaft 4. The pinion 4a is engaged with a rack 5a provided to 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 left direction or a right direction with respect to a traveling direction of the vehicle. Both end portions of the rack shaft 5 have steering tie rods (not shown) and left and right steering wheels (not shown) connected thereto.

[0020] The steering shaft 2 has an outer shaft 11 and an inner shaft 12. The outer shaft 11 and the inner shaft 12 are connected to each other, for example, by spline coupling. The outer shaft 11 and the inner shaft 12 are integrally rotatable and relatively movable in the axial direction of each other. The steering shaft 2 is provided obliquely with respect to the front-rear direction of the vehicle with the steering wheel 6 upward.

[0021] The steering device 1 has a steering column 15. The steering shaft 2 is inserted through the steering column 15. The steering shaft 2 is rotatably supported by the steering column 15 via a bearing (not shown). The steering column 15 is mounted to two frames 13, 14 provided to the vehicle body. One frame 13 is located more rearward than the other frame 14 in the front-rear direction of the vehicle.

[0022] The steering column 15 has an upper tube 16, a lower tube 17, and a housing 18. The upper tube 16 is cylindrical. The lower tube 17 is cylindrical and has a flange 31. The upper tube 16 and the lower tube 17 are fitted to each other. As one example, the upper tube 16 is inserted into a first end portion of the lower tube 17. The first end portion is an end portion on the side opposite to a second end portion provided with the flange 31. The upper tube 16 and the lower tube 17 are relatively movable in the axial direction of the steering shaft 2. The lower tube 17 has a column bracket 17A. The lower tube 17 is mounted to the frame 13 of the vehicle body via the column bracket 17A.

[0023] The upper tube 16 and the lower tube 17 are formed of a magnetic body, for example. The magnetic body contains a magnetic metal such as iron. The upper tube 16 and the lower tube 17 constitute a support cylinder that rotatably supports the steering shaft 2.

[0024] The housing 18 is connected to the second end portion of the lower tube 17. The housing 18 has two support portions 18A (in the figure, only one support portion 18A is shown) that rotatably support the steering column 15. Figure 1(Only one is shown in the figure) and support shaft 18B. Two support portions 18A are provided on the side opposite to the lower tube 17 of the housing 18. The two support portions 18A are opposite to each other in the width direction of the vehicle body. Support shaft 18B extends between the two support portions 18A. Support shaft 18B is rotatably connected to bracket 24 fixed to the frame 14 of the vehicle body.

[0025] A steering assist motor 19 is mounted on the exterior of the housing 18. A speed reducer 20 is housed inside the housing 18. The speed reducer 20 reduces the rotational speed of the motor 19 and transmits this reduced rotational speed to the inner shaft 12. The speed reducer 20 is a worm gear reducer with a worm 21 and a worm wheel 22. The worm 21 is connected to the output shaft of the motor 19 (not shown) in a manner that allows it to rotate integrally. The axis of the worm 21 and the axis of the output shaft of the motor 19 are on the same straight line. The worm wheel 22 meshes with the worm 21. The worm wheel 22 is configured to rotate integrally with the inner shaft 12. The axis of the worm wheel 22 and the axis of the inner shaft 12 are on the same straight line.

[0026] The steering device 1 has a locking mechanism (not shown). The locking mechanism selectively locks and unlocks the swing and extension / retraction of the steering column 15 around its support shaft 18B by operating a lever (not shown). Unlocking the lever allows the steering column 15 to swing relative to the column bracket 17A around its support shaft 18B. After unlocking the lever, the vertical position of the steering wheel 6 can be adjusted by moving it upwards or downwards. Furthermore, unlocking the lever allows the upper tube 16 to move axially relative to the lower tube 17 towards the steering shaft 2. After unlocking the lever, the axial position of the steering wheel 6 can be adjusted by moving it axially towards the steering shaft 2.

[0027] Next, the structure of the lower tube 17 will be explained in detail.

[0028] like Figure 2 As shown, the lower tube 17 has a flange 31. The flange 31 is located at the second end of the lower tube 17. The second end of the lower tube 17 is the end opposite to the first end into which the upper tube 16 is inserted. The flange 31 is an annular plate. The flange 31 has two mounting portions 31A. The two mounting portions 31A are located on the outer peripheral surface of the flange 31. The two mounting portions 31A protrude radially outward from the outer peripheral surface of the flange 31. The two mounting portions 31A are located on opposite sides of the flange 31 in the radial direction. Figure 3 As shown, each of the two mounting portions 31A has a through hole 31B. A bolt 30 is inserted through the through hole 31B. By fastening the bolt 30 to the housing 18, the flange 31 is fixed to the housing 18. The bolt 30 has a head 30A and a shaft portion 30B.

[0029] Next, the structure of the housing 18 will be described in detail.

[0030] As shown in Figure 2 , the housing 18 has a worm gear housing member 41 and a worm housing member 42. The worm gear housing member 41 and the worm housing member 42 are each cylindrical. The worm housing member 42 is joined to the outer peripheral surface of the worm gear housing member 41. The worm housing member 42 extends in a direction orthogonal to the axis of the worm gear housing member 41. The inside of the worm gear housing member 41 and the inside of the worm housing member 42 are in communication with each other via a communication hole (omitted from the drawing). The worm gear housing member 41 constitutes the cylindrical portion of the housing 18. The housing 18 is formed of, for example, a non-magnetic body. The non-magnetic body includes a non-magnetic metal such as aluminum.

[0031] The worm gear 22 is rotatably housed in the inside of the worm gear housing member 41. The worm 21 is rotatably supported in the inside of the worm housing member 42 via a bearing (omitted from the drawing). The worm gear 22 and the worm 21 are engaged with each other via a communication hole provided in the front of the inside of the housing 18. The worm gear 22 and the worm 21 are formed of, for example, a magnetic body. The magnetic body includes a magnetic metal such as iron.

[0032] As shown in Figure 3 , the worm gear housing member 41 has an opening portion 41A at a first end portion in the axial direction, and an end wall at a second end portion on the side opposite to the first end portion. The opening portion 41A opens toward the lower pipe 17 along the axis of the worm gear housing member 41. The outer diameter of the worm gear housing member 41 is virtually the same as the outer diameter of the flange 31.

[0033] The worm gear housing member 41 has a bearing support portion 43 that is cylindrical. The bearing support portion 43 is provided at the end wall of the worm gear housing member 41. The opening portion 41A and the bearing support portion 43 are disposed on the same axis. The inside of the worm gear housing member 41 and the outside of the worm gear housing member 41 are in communication with each other via the bearing support portion 43.

[0034] The worm gear housing member 41 has two fastening portions 44. Each fastening portion 44 is a portion where the bolt 30 is fastened when the flange 31 is fixed to the housing 18. Each fastening portion 44 protrudes to the radially outer side from the outer peripheral surface of the worm gear housing member 41. The two fastening portions 44 are located on opposite sides of each other in the radial direction of the worm gear housing member 41. Each fastening portion 44 has a threaded hole 44A. The end surface of each fastening portion 44 where the threaded hole 44A opens is coplanar with the end surface of the worm gear housing member 41 where the opening portion 41A opens.

[0035] The periphery of flange 31 abuts against the end face of worm gear housing component 41 with opening 41A. The insertion hole 31B of flange 31 and the threaded hole 44A of housing 18 are aligned. Bolt 30 is inserted into the insertion hole 31B of flange 31 from the side opposite to housing 18. Bolt 30 is fastened to fastening portion 44 of housing 18. Thus, flange 31 is fixed to housing 18. That is, lower tube 17 is connected to housing 18 via flange 31. Furthermore, opening 41A of housing 18 is blocked by flange 31. Flange 31 also acts as a cover to close opening 41A of housing 18.

[0036] The worm gear housing component 41 supports the inner shaft 12 for rotation. The inner shaft 12 passes through the worm gear housing component 41. The axis of the inner shaft 12 and the axis of the worm gear housing component 41 are on the same straight line. The inner shaft 12 has an input shaft 12A, an output shaft 12B, and a torsion bar 12C. The input shaft 12A and the output shaft 12B are connected to each other via the torsion bar 12C. The output shaft 12B is a hollow cylinder.

[0037] The first end of the input shaft 12A is connected to the outer shaft 11. The second end of the input shaft 12A is inserted into the first end of the output shaft 12B. There is a gap between the outer circumferential surface of the input shaft 12A and the inner circumferential surface of the output shaft 12B. A sliding bearing 12D is fitted between the outer circumferential surface of the input shaft 12A and the inner circumferential surface of the output shaft 12B. The input shaft 12A and the output shaft 12B can rotate relative to each other via the sliding bearing 12D.

[0038] The first end of the torsion bar 12C is fixed to the second end of the input shaft 12A, inserted into it. The second end of the torsion bar 12C is inserted into the interior of the output shaft 12B. There is a gap between the outer circumferential surface of the torsion bar 12C and the inner circumferential surface of the output shaft 12B. The second end of the torsion bar 12C is fixed to the second end of the output shaft 12B. The steering torque applied to the steering wheel 6 is transmitted to the output shaft 12B via the input shaft 12A and the torsion bar 12C. The torsion bar 12C twists according to the steering torque.

[0039] The worm gear housing 41 houses the worm gear 22 and the bearing support 50. The worm gear 22 is fixed to the outer circumferential surface of the output shaft 12B in a rotatable manner. The bearing support 50 is cylindrical and is mounted to the outer circumferential surface of the output shaft 12B in a relatively restrictive manner. The worm gear 22 and the bearing support 50 are arranged at intervals along the axial direction of the worm gear housing 41. The worm gear 22 is disposed between the bearing support 50 and the end wall of the worm gear housing 41. The worm gear housing 41, the worm gear 22, and the bearing support 50 are arranged coaxially.

[0040] like Figure 4 as well as Figure 5As shown, the bearing support member 50 has a cylindrical inner peripheral wall 51, a cylindrical outer peripheral wall 52, and an annular connecting wall 53.

[0041] The inner peripheral wall 51 is located radially inward of the outer peripheral wall 52. The axial position of the inner peripheral wall 51 is slightly different from the axial position of the outer peripheral wall 52. The connecting wall 53 is a wall portion that extends radially of the bearing support member 50. The connecting wall 53 connects the base end portion of the inner peripheral wall 51 with the base end portion of the outer peripheral wall 52. The front end portion of the inner peripheral wall 51 and the front end portion of the outer peripheral wall 52 face opposite sides of each other in the axial direction. The front end portion is the end portion on the side opposite the base end portion.

[0042] The connecting wall 53 has an inner side flat portion 53A, an inclined portion 53B, and an outer side flat portion 53C. The inner side flat portion 53A, the inclined portion 53B, and the outer side flat portion 53C are connected in this order with the inner peripheral wall 51 as a reference. The inner side flat portion 53A and the outer side flat portion 53C extend in a direction orthogonal to the axial direction. The inner peripheral portion of the inner side flat portion 53A is connected with the base end portion of the inner peripheral wall 51. The outer peripheral portion of the outer side flat portion 53C is connected with the base end portion of the outer peripheral wall 52. The outer side flat portion 53C is disposed at a position offset toward the front end portion side of the inner peripheral wall 51 in the axial direction of the bearing support member 50, relative to the inner side flat portion 53A. The inclined portion 53B is inclined in such a manner that the closer to the front end portion of the inner peripheral wall 51 in the axial direction of the bearing support member 50, the more outward in the radial direction of the connecting wall 53.

[0043] The inner diameter of the inner peripheral wall 51 is set to be slightly smaller than the outer diameter of the bearing 71. The outer diameter of the outer peripheral wall 52 is set to be slightly larger than the inner diameter of the worm wheel housing member 41. The inner diameter of the inner peripheral wall 51 and the outer diameter of the outer peripheral wall 52 are determined in accordance with the determined press-in amount.

[0044] The bearing support member 50 is formed by bending a single sheet of material. The bearing support member 50 is formed of a magnetic material, for example. The magnetic material includes a magnetic metal such as iron. The bearing support member 50 is formed by plastically deforming a single sheet of metal material, for example, by press punching into a prescribed shape by a press machine.

[0045] As Figure 3As shown, the inner circumferential surface of the bearing support member 50, i.e., the inner circumferential surface of the inner circumferential wall 51, fits into the outer circumferential surface of the bearing 71. The outer circumferential surface of the bearing support member 50, i.e., the outer circumferential surface of the outer circumferential wall 52, fits into the inner circumferential surface of the worm gear housing member 41. The bearing support member 50 is pressed into the inner circumferential surface of the worm gear housing member 41 from the mounting direction DW. The mounting direction DW is along the axis of the worm gear housing member 41, and is the direction in which the bearing support member 50 is inserted into the worm gear housing member 41. The axial position of the bearing support member 50 relative to the worm gear housing member 41 is determined by managing the pressing stroke of the pressing device (not shown). The inner circumferential wall 51 extends from the connecting wall 53 in the same direction as the mounting direction DW. The outer circumferential wall 52 extends from the connecting wall 53 in the opposite direction to the mounting direction DW. The front end of the inner circumferential wall 51 faces the same direction as the mounting direction DW. The front end of the outer circumferential wall 52 faces the opposite direction to the mounting direction DW. The base end of the outer peripheral wall 52 is positioned offset from the base end of the inner peripheral wall 51 in the mounting direction DW. The inclined portion 53B is inclined such that the portion further outward in the radial direction is displaced towards the mounting direction DW.

[0046] The output shaft 12B is supported by the inner circumferential surface of the bearing support portion 43 via the bearing 61, allowing it to rotate. The bearing 61 is in a state that restricts axial movement. An annular stepped portion 62 and a retaining ring 63 are provided on the outer circumferential surface of the output shaft 12B. The inner ring of the bearing 61 is clamped between the stepped portion 62 and the retaining ring 63. An annular protrusion 64 and a retaining ring 65 are provided on the inner circumferential surface of the bearing support portion 43. The outer ring of the bearing 61 is clamped between the protrusion 64 and the retaining ring 65.

[0047] The output shaft 12B is supported by the inner peripheral wall 51 of the bearing support member 50 via the bearing 71, enabling it to rotate. The bearing 71 is in a state that restricts axial movement. An annular protrusion 72 is provided on the outer peripheral surface of the output shaft 12B. In addition, a cylindrical nut member (not shown) is installed at the first end of the output shaft 12B. The inner ring of the bearing 71 is clamped between the protrusion 72 and the nut member. The outer ring of the bearing 71 is maintained in a state where it is elastically pressed radially inward by the inner peripheral wall 51. The outer ring of the bearing 71 is supported by the inner peripheral wall 51.

[0048] The internal space of the worm gear housing component 41 is divided into two spaces by the bearing support component 50. A sensor 80 is disposed in the space between the bearing support component 50 and the flange 31. The sensor 80 includes a torque sensor and a rotation angle sensor. The torque sensor detects the steering torque based on the torsion of the torsion bar 12C. The rotation angle sensor detects the rotation angle of the input shaft 12A as the steering angle. Grease is sealed in the space between the bearing support component 50 and the end wall of the worm gear housing component 41.

[0049] <The function and effects of the first embodiment>

[0050] The first implementation method has the following functions and effects.

[0051] (1-1) As Figure 6 As shown, the bearing support member 50 is mounted on the worm gear housing member 41 with its outer peripheral wall 52 facing in the opposite direction to the mounting direction DW. When the bearing support member 50 is pressed into the worm gear housing member 41, the outer peripheral surface of the outer peripheral wall 52 slides relative to the inner peripheral surface of the worm gear housing member 41. At this time, a sliding resistance acts on the outer peripheral wall 52 in the opposite direction to the mounting direction DW. Due to this sliding resistance, the connecting wall 53, with the connection portion between the inner peripheral wall 51 and the inner flat portion 53A as the fulcrum, slightly elastically deforms in a manner that is inclined in the opposite direction to the mounting direction DW. Accompanying this, the outer diameter of the front end of the outer peripheral wall 52 is slightly reduced as it tilts radially inward through the front end.

[0052] Therefore, the contact area between the outer peripheral surface of the outer peripheral wall 52 and the worm gear housing component 41 is reduced. Furthermore, due to the reduced contact area, the sliding resistance between the outer peripheral wall 52 and the worm gear housing component 41 is reduced. The bearing support component 50 can be easily inserted into the worm gear housing component 41, thus improving assemblability. Additionally, the pressing load can be reduced. The pressing load is the force required to press the bearing support component 50 into the worm gear housing component 41. Therefore, a new steering device 1 that allows for easy pressing of the bearing support component 50 into the worm gear housing component 41 can be obtained.

[0053] (1-2) Due to reasons such as vehicles riding on curbs or the end application of rack shaft 5, there are concerns about the so-called reverse input load F acting on output shaft 12B. End application refers to the situation where the end of rack shaft 5 abuts against housing 10. The reverse input load F is a force in the opposite direction to the mounting direction DW. For example... Figure 7 As shown, the reverse input load F is transmitted to the inner peripheral wall 51 of the bearing support member 50 via the output shaft 12B and the bearing 71. Under this reverse input load F, a force is applied to the connecting wall 53, attempting to tilt it in the same direction as the mounting direction DW, with the connection between the inner peripheral wall 51 and the inner flat portion 53A as the fulcrum. Simultaneously, a force is applied to the outer peripheral wall 52, attempting to tilt its front end radially outward by expanding its outer diameter.

[0054] Therefore, the outer peripheral surface of the outer peripheral wall 52 is pressed more strongly to the radially outer side with respect to the inner peripheral surface of the worm housing member 41. Since the contact load of the outer peripheral surface of the outer peripheral wall 52 with respect to the inner peripheral surface of the worm housing member 41 increases, the drop load of the bearing support member 50 increases. The drop load is a force required to move the bearing support member 50 in a state of being pressed into the worm housing member 41 in the direction opposite to the mounting direction DW. Therefore, by the increase in the drop load, the movement of the bearing support member 50 in the direction opposite to the mounting direction DW is suppressed. For example, even if the reverse input load F acts on the output shaft 12B, the bearing support member 50 is maintained at the appropriate axial position. A new steering apparatus 1 in which the bearing support member 50 is difficult to drop in the direction opposite to the mounting direction DW can be obtained.

[0055] Further, it is also considered that the outer peripheral wall 52 is designed to face in the same direction as the mounting direction DW. In this case, when the reverse input load F acts on the output shaft 12B, the link wall 53 is slightly elastically deformed in a manner of tilting in the same direction as the mounting direction DW with the joint portion of the inner peripheral wall 51 and the inner side flat portion 53A as a fulcrum. Along therewith, since the front end portion of the outer peripheral wall 52 tilts to the radially inner side, the outer diameter of the front end portion of the outer peripheral wall 52 is slightly reduced. Therefore, since the contact load of the outer peripheral surface of the outer peripheral wall 52 with respect to the inner peripheral surface of the worm housing member 41 decreases, there is a concern that the drop load of the bearing support member 50 decreases. Therefore, from the viewpoint of securing the drop load of the bearing support member 50, it is preferable that the outer peripheral wall 52 is designed to face in the direction opposite to the mounting direction DW.

[0056] (1-3) The bearing support member 50 is maintained in a state of being pressed into the inner peripheral surface of the worm housing member 41. Therefore, it is not necessary to provide other members for maintaining the axial position of the bearing support member 50. In addition, it is not necessary to fasten the bearing support member 50 to the worm housing member 41 with a bolt or the like fastening member. Therefore, it is possible to suppress the increase in the number of components of the steering apparatus 1. In addition, it is possible to reduce the product cost of the steering apparatus 1.

[0057] (1-4) The bearing support member 50 is maintained in a state of being pressed into the inner peripheral surface of the worm housing member 41. The inner peripheral surface of the inner peripheral wall 51 is maintained in a state of being elastically pressed to the radially inner side with respect to the outer peripheral surface of the outer ring of the bearing 71. Ideally, there is no gap between the inner peripheral surface of the inner peripheral wall 51 and the outer peripheral surface of the outer ring of the bearing 71. Therefore, the lubricating grease is difficult to pass through the boundary portion between the inner peripheral surface of the inner peripheral wall 51 and the outer peripheral surface of the outer ring of the bearing 71. Therefore, it is possible to suppress the case where the lubricating grease leaks from the first space between the bearing support member 50 and the end wall of the worm housing member 41 to the second space between the bearing support member 50 and the flange 31.

[0058] Further, the outer peripheral surface of the outer peripheral wall 52 is maintained in a state of being elastically pressed to the radially outer side with respect to the inner peripheral surface of the worm housing member 41. Ideally, there is no gap between the outer peripheral surface of the outer peripheral wall 52 and the inner peripheral surface of the worm housing member 41. Therefore, it is difficult for the lubricating grease to pass through the boundary portion of the outer peripheral surface of the outer peripheral wall 52 and the inner peripheral surface of the worm housing member 41. Therefore, it is possible to suppress the case where the lubricating grease leaks from the first space between the bearing support member 50 and the end wall of the worm housing member 41 to the second space between the bearing support member 50 and the flange 31.

[0059] (1-5) Ideally, there is no gap between the inner peripheral surface of the inner peripheral wall 51 and the outer peripheral surface of the outer ring of the bearing 71. Therefore, it is possible to suppress the case where a knocking sound or a stick-slip sound is generated between the bearing support member 50 and the bearing 71. The stick-slip sound is an abnormal noise generated due to the friction between the bearing support member 50 and the bearing 71. Therefore, it is possible to improve the quietness of the steering apparatus 1.

[0060] (1-6) The connecting wall 53 has an inclined portion 53B. By adjusting the degree of inclination of the inclined portion 53B, it is possible to adjust the load deflection characteristic of the connecting wall 53. The load deflection characteristic is a case where the load acting on a member and the deflection amount of the member with respect to the load are related.

[0061] (1-7) The bearing support member 50 is made by bending a single sheet material. The sheet material is, for example, a metal sheet material having magnetism. Therefore, it is possible to simply mold the bearing support member 50 by a press machine or the like. Further, it is possible to make the bearing support member 50 lightweight.

[0062] (1-8) The bearing support member 50 is made of metal. Therefore, for example, at the time of mounting the bearing support member 50 to the worm housing member 41, it is possible to suppress the damage of the bearing support member 50.

[0063] (1-9) Since it is possible to assemble the worm 22, the bearing support member 50, and the sensor 80 in one direction with respect to the mounting direction DW in the worm housing member 41, the assemblability is improved.

[0064] <Second Embodiment>

[0065] A second embodiment of a steering apparatus will be described. This embodiment basically has the same structure as the first embodiment shown in FIG. 1. Therefore, the same components and the same structures as the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted. Figures 1 to 7

[0066] ​Sensor 80 includes a magnetic torque sensor. The torque sensor has a permanent magnet fixed to the input shaft 12A and a yoke unit fixed to the output shaft 12B. The yoke unit is a unit in which two yokes are integrated via a resin portion. If a torque is applied to the input shaft 12A and the torsion bar 12C is torsional, the relative position of the permanent magnet and the yoke changes in the direction of rotation. The torque sensor detects the torque applied to the torsion bar 12C based on the change in magnetic flux of the yoke accompanying the change in the relative position of the permanent magnet and the yoke. The permanent magnet and the two yokes form a magnetic circuit.

[0067] When a magnetic field source, such as a vehicle speaker, is present near the steering device 1, there is a concern that magnetic flux generated from the magnetic field source may be applied to the sensor 80 via a first magnetic flux path R1. The first magnetic flux path R1 is a path that includes the upper tube 16, the lower tube 17, and the sensor 80. In this case, the torque detection accuracy of the sensor 80 may be reduced due to the influence of the magnetic field from the magnetic field source. Therefore, in this embodiment, the steering device 1 employs the following structure.

[0068] like Figure 8 As shown, the steering device 1 has two magnetic circuit components 81. Magnetic circuit components 81 are used to connect the flange 31 to the outer peripheral wall 51 of the bearing support component 50. Magnetic circuit components 81 are formed of a magnetic metal. Magnetic circuit components 81 are formed by bending a single sheet of metal. Magnetic circuit components 81 are formed by plastically deforming a single sheet of metal, for example, by stamping it into a predetermined shape using a press.

[0069] The magnetic circuit component 81 has a first magnetic circuit portion 81A and a second magnetic circuit portion 81B. The first magnetic circuit portion 81A extends radially along the worm gear housing component 41. The first magnetic circuit portion 81A is flat and is sandwiched between the fastening portion 44 of the worm gear housing component 41 and the mounting portion 31A of the flange 31. The first magnetic circuit portion 81A is axially fixed together with the mounting portion 31A and the fastening portion 44 by bolts 30. A portion of the first radial end of the first magnetic circuit portion 81A may also be exposed to the outside of the housing 18. The second radial end of the first magnetic circuit portion 81A is located inside the housing 18.

[0070] The second magnetic path portion 81B is inclined so as to approach the inner circumferential surface of the worm housing member 41 as the bearing support member 50 is oriented in the direction of installation DW. The first end portion of the second magnetic path portion 81B is connected to the second end portion of the first magnetic path portion 81A. The connecting portion of the first magnetic path portion 81A and the second magnetic path portion 81B is smoothly curved. The second end portion of the second magnetic path portion 81B is curved toward the radially inner side of the worm housing member 41. The curved convex portion of the second end portion functions as a contact portion 81C against the bearing support member 50. The contact portion 81C is maintained in a state of being elastically pressed toward the radially outer side with respect to the inner circumferential surface of the outer circumferential wall 52.

[0071] The distance between the bearing support member 50 and the worm 22 in the axial direction is set to a distance through which the magnetic flux from the assumed magnetic field generation source can pass. In addition, the upper tube 16, the lower tube 17, the flange 31, the magnetic path member 81, the bearing support member 50, and the worm 22 are all formed of a magnetic metal. Therefore, the upper tube 16, the lower tube 17, the flange 31, the magnetic path member 81, the bearing support member 50, and the worm 22 can be magnetically coupled to each other, and the second magnetic flux path R2 can be formed. The second magnetic flux path R2 is a magnetic flux path that bypasses the surroundings of the sensor 80.

[0072] Ideally, there is no gap between the flange 31 and the first magnetic path portion 81A. In contrast, the flange 31 and the magnetic member of the sensor 80 are distanced in the axial direction. That is, the magnetic resistance between the flange 31 and the first magnetic path portion 81A is smaller than the magnetic resistance between the flange 31 and the magnetic member of the sensor 80. The magnetic member is a permanent magnet and a magnetic yoke. Therefore, the magnetic flux applied from the outside of the steering apparatus 1 more easily flows to the first magnetic path portion 81A than to the magnetic member of the sensor 80.

[0073] The distance in the axial direction between the front end portion of the inner circumferential wall 51 of the bearing support member 50 and the worm 22 is shorter than the distance in the axial direction between the flange 31 and the magnetic member of the sensor 80. In addition, the distance in the axial direction between the front end portion of the inner circumferential wall 51 of the bearing support member 50 and the worm 22 is shorter than the distance in the axial direction between the magnetic member of the sensor 80 and the worm 22. Therefore, overall, the magnetic resistance of the second magnetic flux path R2 is smaller than the magnetic resistance of the first magnetic flux path R1.

[0074] Furthermore, there can be a slight gap between the flange 31 and the first magnetic path portion 81A. However, the gap is shorter than the distance in the axial direction between the flange 31 and the magnetic member of the sensor 80. In addition, there can be a slight gap between the contact portion 81C and the inner circumferential surface of the outer circumferential wall 52. However, the gap is a gap through which the magnetic flux from the assumed magnetic field generation source can pass.

[0075] Effects of the Second Embodiment

[0076] The second embodiment achieves the effects of the first embodiment described in the columns of (1-1) to (1-9) above, in addition to achieving the effects described below.

[0077] (2-1) The magnetic reluctance of the second magnetic flux path R2 that does not include the sensor 80 is smaller than the magnetic reluctance of the first magnetic flux path R1 that includes the sensor 80. Therefore, magnetic flux applied from the outside of the steering apparatus 1 does not pass through the first magnetic flux path R1 that includes the sensor 80, but passes through the second magnetic flux path R2 that bypasses the radial outer side of the sensor 80. By suppressing the case where magnetic flux from the magnetic field generation source is applied to the sensor 80, the detection accuracy of the sensor 80 can be ensured.

[0078] Furthermore, in the case where the bearing support member 50 is formed of a non-magnetic material such as a synthetic resin, it is difficult to form the second magnetic flux path R2 that bypasses the radial outer side of the sensor 80. In this case, the possibility that magnetic flux from the magnetic field generation source passes through the first magnetic flux path R1 that includes the sensor 80 is high.

[0079] (2-2) The second magnetic flux path R2 that bypasses the sensor 80 is formed using the flange 31, the bearing support member 50, and the worm wheel 22 and the like, which are magnetic members. It is also possible to provide only the magnetic path member 81 that magnetically couples the flange 31 and the bearing support member 50. Therefore, compared to the case where, for example, a magnetic shield that covers the surroundings of the sensor 80 is provided, it is possible to reduce the product cost. The magnetic shield is complicated to process, so there is a concern that the product cost will increase. According to the present embodiment, by magnetically coupling the parts of the members that exist in the surroundings of the sensor 80 and that are magnetic to each other, it is possible to provide the steering apparatus 1 with the function of the magnetic shield that cuts off the influence of the external magnetic field on the sensor 80.

[0080] <Other Embodiments>

[0081] Furthermore, the first and second embodiments can also be implemented by being changed as follows.

[0082] In the first embodiment, the bearing support member 50 and the housing 18 can also be made of synthetic resin. Synthetic resin materials are less expensive than metal materials. Therefore, it is possible to reduce the product cost of the steering apparatus 1.

[0083] In the first embodiment, the inclined portion 53B of the connecting wall 53 can also be omitted. In this case, the connecting wall 53 is a flat wall portion that extends in the radial direction.

[0084] In the second embodiment, the magnetic path member 81 can also be provided only one. Alternatively, three or more magnetic path members 81 can be provided.

[0085] In the second embodiment, the magnetic path member 81 can also be omitted depending on the product specifications and the like. In this case, the axial distance between the flange 31 and the outer peripheral wall 52 is shortened, for example, to the extent that the flange 31 and the outer peripheral wall 52 can be magnetically coupled. For example, the outer peripheral wall 52 can be extended in the direction opposite to the mounting direction DW. The extent that the flange 31 and the outer peripheral wall 52 can be magnetically coupled is the extent that the magnetic flux from the magnetic flux generation source can pass from the flange 31 to the outer peripheral wall 52.

[0086] In the second embodiment, in the case where the magnetic path member 81 is omitted, the housing 18 can also be formed of a magnetic metal. In this case, the magnetic flux from the magnetic flux generation source passes, for example, in the order of the flange 31, the worm wheel housing member 41, and the bearing support member 50.

[0087] In the second embodiment, the second magnetic flux path R2 can also be configured to include a member that contacts the output shaft 12B. For example, in the case where the outer ring, the inner ring, and the balls of the bearing 71 are products made of a magnetic metal, the bearing 71 can constitute a part of the second magnetic flux path R2.

[0088] Depending on the specifications of the product and the like, the steering device 1 can not be provided with a structure for adjusting the up-and-down position of the steering wheel 6 and a structure for adjusting the position in the axial direction of the steering wheel 6. In this case, instead of the upper pipe 16 and the lower pipe 17, a single support tube that does not stretch and contract is provided. The steering shaft 2 is supported so as to be rotatable by the single support tube. In addition, the housing 18 is fixed to the frame 14 of the vehicle body. A structure in which the support portion 18A and the support shaft 18B are omitted from the housing 18 can be employed. In addition, a lock mechanism that selectively locks and unlocks the swing of the steering column 15 about the support shaft 18B and the stretching and contraction of the steering column 15 is not required.

[0089] The steering device 1 can also be an electric power steering type steering device. In this case, the power transmission between the steering wheel 6 and the steered wheels is separated. The motor 19 functions as a reaction force motor. The reaction force motor generates a steering control reaction torque that is applied to the steering shaft 2 of the vehicle. The steering control reaction torque is a torque in the direction opposite to the steering control direction of the steering wheel 6.

Claims

1. A steering device comprising: A cylindrical support tube with a flange supports the steering shaft so that it can rotate; The speed reducer is configured to apply torque to the aforementioned steering shaft; The housing has a cylindrical portion for housing the aforementioned reducer, the cylindrical portion being coaxially connected to the aforementioned flange; A bearing support component, which fits into the inner circumferential surface of the aforementioned cylindrical portion in the axial direction, i.e., the mounting direction, and through which the aforementioned steering shaft passes; and The bearing is clamped between the outer circumferential surface of the steering shaft and the inner circumferential surface of the bearing support component. The aforementioned bearing support component has an inner peripheral wall that fits into the outer peripheral surface of the bearing, an outer peripheral wall that fits into the inner peripheral surface of the cylindrical portion, and a connecting wall that connects the inner peripheral wall and the outer peripheral wall radially. The aforementioned inner peripheral wall has a base end portion connected to the aforementioned connecting wall, and extends from the aforementioned connecting wall in the same direction as the aforementioned mounting direction. The aforementioned outer peripheral wall has a base end connected to the aforementioned connecting wall, and extends from the aforementioned connecting wall in a direction opposite to the aforementioned mounting direction. The aforementioned bearing support component is fixed inside the aforementioned housing only through the aforementioned fitting. The aforementioned housing does not have a structure that restricts the axial position of the aforementioned bearing support component.

2. The steering device according to claim 1, wherein, The aforementioned connecting wall has an inclined portion that tilts in such a way that the portion further outward in the radial direction is displaced in the aforementioned installation direction.

3. The steering device according to claim 1 or 2, wherein, The aforementioned bearing support component is made of a single bent sheet metal.

4. The steering device according to claim 1 or 2, wherein, The aforementioned bearing support components are made of metal.

5. The steering device according to claim 1 or 2, wherein, It has a magnetic sensor, which is disposed inside the housing in the space between the flange and the bearing support member. The aforementioned flange and bearing support component are made of magnetic metal, while the aforementioned housing is made of non-magnetic metal. The aforementioned flange and bearing support components are configured to form a magnetic flux path that bypasses the sensor.

6. The steering device according to claim 5, wherein, A magnetic circuit component made of magnetic metal that connects the aforementioned flange to the aforementioned outer peripheral wall.

7. The steering device according to claim 1 or 2, wherein, The aforementioned reducer has a worm gear that rotates integrally with the aforementioned steering shaft, and a worm that meshes with the aforementioned worm gear. The aforementioned housing includes a worm gear housing component for housing the worm gear and a worm gear housing component for housing the worm. The aforementioned cylindrical portion is the aforementioned worm gear housing component.

Images