Steering operation input device and steer-by-wire steering device

Abstract

This steering operation input device comprises: a first shaft (19); a second shaft (20); a connection member (13) provided between the first shaft (19) and the second shaft (20); a first torsion spring (16) provided on the first shaft (19) and connected to the connection member (13); and a second torsion spring (17) provided on the second shaft (20). The second torsion spring (17) has the same spring constant as the first torsion spring (16), and is preloaded. Until the first shaft (19) is twisted by 60 degrees in a predetermined rotation direction, the biasing force of the first torsion spring (16) acts on the first shaft (19). After the first shaft (19) is twisted by 60 degrees in the predetermined rotation direction, the biasing forces of the first torsion spring (16) and the second torsion spring (17) act on the first shaft (19).

Description

[Technical Field]

[0001] The present invention relates to a steering operation input device and a steer-by-wire type steering device. [Background technology]

[0002] As a steering operation input device, for example, the steering operation input device described in Patent Document 1 below is known.

[0003] The steering operation input device of Patent Document 1 has a first biasing member that generates a reaction force against one rotation direction of a steering operation input member of the steering device, and a second biasing member that generates a reaction force against the other rotation direction opposite to the one rotation direction of the steering operation input member. Switching between reaction force generation by the first biasing member and the second biasing member is performed via a linear motion conversion device that converts the rotational force input from the steering operation input member into linear motion. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-082071 Summary of the Invention [Problem to be solved by the invention]

[0005] In the steering operation input device of Patent Document 1, a dedicated biasing member is provided to generate a reaction force against each rotational direction of the steering operation input member, which increases the number of parts in the steering operation input device, resulting in a problem of increased manufacturing costs for the steering operation input device.

[0006] The present invention has been devised in view of the conventional situation, and one object of the present invention is to provide a steering operation input device that can reduce manufacturing costs. [Means for solving the problem]

[0007] In one aspect of the present invention, the steering operation input device has a biasing member that applies a biasing force against the rotation of the shaft, and this biasing member includes a first biasing member that applies a biasing force to the shaft regardless of the rotation direction of the shaft, and a second biasing member that is attached in a preloaded state and applies a biasing force to the shaft regardless of the rotation direction of the shaft after the first biasing member applies a biasing force. [Effects of the Invention]

[0008] According to the present invention, the manufacturing cost of the steering operation input device can be reduced. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a schematic diagram of a steer-by-wire steering system to which a steering operation input device of the present invention is applied. [Figure 2] 1 is a vertical cross-sectional view of a steering operation input device according to a first embodiment. [Figure 3] 10 is an explanatory diagram showing the positional relationship between a first torsion spring and the first and second arcuate grooves of the first shaft in a neutral position when viewed in the axial direction of the first shaft. FIG. [Figure 4] 10 is an explanatory diagram showing the positional relationship between the first torsion spring and the first and second arcuate grooves of the first shaft when rotated clockwise from the neutral position. FIG. [Figure 5] 10 is an explanatory diagram showing the positional relationship between the first torsion spring and the first and second arcuate grooves of the first shaft when rotated left from the neutral position. FIG. [Figure 6] 4 is a graph showing an operation force relative to an operation angle in the first embodiment. [Figure 7] FIG. 6 is a vertical cross-sectional view of a steering operation input device according to a second embodiment. [Figure 8] (a) is an explanatory diagram showing the steering operation input device when the third shaft is rotated 180 degrees to the left from the neutral position, (b) is an explanatory diagram showing the steering operation input device when the third shaft is rotated 60 degrees to the left from the neutral position, and (c) is an explanatory diagram showing the steering operation input device in the neutral position. [Figure 9] (a) is an explanatory diagram showing the steering operation input device in the neutral position, (b) is an explanatory diagram showing the steering operation input device when the third shaft is rotated to the right by 60 degrees from the neutral position, and (c) is an explanatory diagram showing the steering operation input device when the third shaft is rotated to the right by 180 degrees from the neutral position. [Figure 10] 11 is a graph showing the operation force relative to the operation angle in the third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, an embodiment of a steering operation input device of the present invention will be described with reference to the drawings. The following embodiment will be described as an example in which the steering operation input device is applied to a steer-by-wire steering device mounted on a vehicle.

[0011] [First embodiment] FIG. 1 is a schematic diagram of a steer-by-wire steering system to which the steering operation input device of the present invention is applied.

[0012] The steer-by-wire steering device is configured so that a steering operation input device (described below), in which a steering operation is input via a dial 1, which is a steering operation input member used by a driver to perform steering operations, and a steering mechanism 3 that steers a pair of steerable wheels 2, 2, are mechanically separated.

[0013] Dial 1 is fixed to one end of shaft 4, which is a column shaft provided in the steering operation input device. Note that instead of dial 1, another steering operation input member, for example, a steering wheel, may be fixed to one end of shaft 4. An operation angle sensor 6 is provided on the outer periphery of shaft 4 to detect the operation angle (steering angle) of shaft 4 associated with the driver's steering operation. An operation angle signal detected by operation angle sensor 6 is transmitted to control device 7. In addition, various detection signals other than the steering angle signal are transmitted to control device 7 by external sensor 8. Control device 7 controls electric motor 9 provided in steering mechanism 3 based on the steering angle signal, a steering amount signal described below, and various detection signals.

[0014] The steering mechanism 3 includes a steering shaft 10, a pair of tie rods 11, 11 connected to both ends of the steering shaft 10 and steering the pair of steerable wheels 2, 2, an electric motor 9 that controls the steering operation of the steering shaft 10, and a steering amount sensor 12 that detects a steering amount signal of the steering shaft 10. The steering amount signal detected by the steering amount sensor 12 is sent to the control device 7.

[0015] FIG. 2 is a longitudinal cross-sectional view of the steering operation input device of the first embodiment. For simplicity, the operation angle sensor 6 is omitted from FIG. 2. FIG. 3 is an explanatory diagram showing the positional relationship between the first torsion spring 16 and the first and second arcuate grooves 23 and 24 of the first shaft 19 at the neutral position when viewed from the axial direction of the first shaft 19. Although FIG. 3 shows the first and second arcuate grooves 23 and 24 as being formed on the same plane, in reality, the first arcuate groove 23 is formed on one axial end face 19h, while the second arcuate groove 24 is formed on the other axial end face 19i, which is shifted from the one axial end face 19h toward the other end 19b of the first shaft 19. FIG. 4 is an explanatory diagram showing the positional relationship between the first torsion spring 16 and the first and second arcuate grooves 23 and 24 of the first shaft 19 when the first shaft 19 is rotated clockwise from the neutral position. Fig. 5 is an explanatory diagram showing the positional relationship between first torsion spring 16 and first arcuate groove 23 and second arcuate groove 24 of first shaft 19 when rotated left from the neutral position. Fig. 6 is a graph showing the operating force versus the operating angle in the first embodiment.

[0016] The steering operation input device includes a shaft 4, a connecting member 13, a connecting member cover 14, a housing 15, a first torsion spring (first biasing member) 16, a second torsion spring (second biasing member) 17, and a blocking member 18.

[0017] The shaft 4 includes a first shaft 19 to which the operating force from the dial 1 is transmitted and which rotates about a rotation axis O, and a second shaft 20 connected to the first shaft 19 via a connecting member 13 and a first torsion spring 16. For convenience of the following description, in FIG. 2, of both axial ends 19a, 19b of the first shaft 19, the end to which the dial 1 is fixed is defined as the "one end 19a," and the end opposite the end to which the dial 1 is fixed is defined as the "other end 19b." In addition, in FIG. 3, a center line that passes through the rotation axis O of the first shaft 19 and divides the first shaft 19 into left and right halves is defined as a "first center line X1," and a center line that passes through the rotation axis O of the first shaft 19 and is perpendicular to the first center line X1 is defined as a "second center line X2." The direction along the second center line X2 in FIG. 3 coincides with the left-right direction in FIG. 2.

[0018] The shaft 4 has a first small diameter portion 19c which is an axial portion located on the one end 19a side, a medium diameter portion 19d which is an axial portion formed integrally with the first small diameter portion 19c and has a larger diameter than the first small diameter portion 19c, a large diameter portion 19e which is an axial portion formed integrally with the medium diameter portion 19d and has a larger diameter than the medium diameter portion 19d, and a second small diameter portion 19f which is an axial portion formed integrally with the large diameter portion 19e and has a smaller diameter than the large diameter portion 19e.

[0019] A D-cut portion 19g for engagement with the dial 1 is formed on the outer periphery of the first small diameter portion 19c on one end 19a side. The D-cut portion 19g is fixed to the dial 1 via, for example, a well-known key connection. A first ball bearing 21, which is a bearing for rotatably supporting the first small diameter portion 19c, is provided on the outer periphery of the axial center portion of the first small diameter portion 19c. Furthermore, a second ball bearing 22, which is a bearing for rotatably supporting the first small diameter portion 19c, is provided on the outer periphery of the axial end portion of the first small diameter portion 19c located on the other end 19b side.

[0020] Large diameter portion 19e is a shaft portion around which first torsion spring 16 is attached. The outer diameter of large diameter portion 19e is set to be smaller than the inner diameter of first torsion spring 16 when it is twisted and maximally compressed. As shown in Fig. 2, large diameter portion 19e is located on one end 19a side and has one axial end face 19h which is a continuous ring-shaped surface, and another axial end face 19i which is located on the other end 19b side and is also a continuous ring-shaped surface.

[0021] A first arc-shaped groove 23 is formed in the axial end face 19h at a position closer to the outer periphery of the first shaft 19, on the side where the D-cut portion 19g of the first small diameter portion 19c of the first shaft 19 is provided. The first arc-shaped groove 23 is concentric with the outer periphery of the first shaft 19. As shown in FIG. 3 , the first arc-shaped groove 23 is located to the left of the first center line X1 and extends counterclockwise from the second center line X2 at a predetermined angle, 180 degrees in this embodiment. Note that the first arc-shaped groove 23 may be formed so as to continue in an arc shape at any angle other than 180 degrees. The first arc-shaped groove 23 has a first groove end portion 23a adjacent to the second center line X2 and a second groove end portion (not shown) on the opposite side of the first groove end portion 23a. As shown in FIG. 3, when first torsion spring 16 is in the neutral state, first bent portion 16e of first spring end 16b (described later) of first torsion spring 16 is positioned at first groove end 23a of first arc groove 23.

[0022] Meanwhile, a second arc-shaped groove 24 is formed in the other axial end face 19i near the outer periphery of the first shaft 19 and diagonally across the rotation axis O of the first shaft 19 from the first arc-shaped groove 23. The second arc-shaped groove 24 is concentric with the outer periphery of the first shaft 19 and has a similar shape to the first arc-shaped groove 23. As shown in FIG. 3 , the second arc-shaped groove 24 is located to the right of the first center line X1 and extends counterclockwise from the second center line X2 at a predetermined angle—180 degrees in this embodiment. Note that the second arc-shaped groove 24 may be formed so as to extend continuously in an arc shape at any angle other than 180 degrees. The second arc-shaped groove 24 has a third groove end 24a adjacent to the second center line X2 and a fourth groove end (not shown) on the opposite side of the third groove end 24a. As shown in FIG. 3, when first torsion spring 16 is in a neutral state, second bent portion 16g of second spring end portion 16c (described later) of first torsion spring 16 is positioned at third groove end portion 24a of second arcuate groove 24.

[0023] A third ball bearing 25, which is a bearing that rotatably supports second small diameter portion 19f, is provided on the outer periphery of second small diameter portion 19f. Second small diameter portion 19f also has a stepped reduced diameter portion 19j whose tip is formed in a stepped reduced diameter shape. A fourth ball bearing 26, which is a bearing that rotatably supports stepped reduced diameter portion 19j, is provided on the outer periphery of stepped reduced diameter portion 19j.

[0024] The second shaft 20 is formed in a cylindrical shape with an outer diameter larger than that of the large diameter portion 19e of the first shaft 19. The second shaft 20 has a circular first through hole 20a in its center, and a small diameter cylindrical portion 13a (described below) of the connecting member 13 is inserted into the first through hole 20a, with the first small diameter portion 19c of the first shaft 19 passing through it. The second shaft 20 has an axial one end side end face 20b, which is located on the one end 19a side and is a continuous ring-shaped surface, and an axial other end side end face 20c, which is located on the other end 19b side and is also a continuous ring-shaped surface.

[0025] A third arc-shaped groove 27 is formed in one axial end face 20b at a position closer to the outer periphery of second shaft 20. The third arc-shaped groove 27 is concentric with the outer periphery of second shaft 20. The third arc-shaped groove 27 has the same shape as first arc-shaped groove 23, but is provided at a position further outward than first arc-shaped groove 23 in the radial direction of first shaft 19. The positional relationship between third arc-shaped groove 27 and a third protrusion 36 (described below) when second torsion spring 17 is in the neutral position is the same as the positional relationship between first arc-shaped groove 23 and first protrusion 30 when first torsion spring 16 is in the neutral state (the positional relationship shown in FIG. 3).

[0026] Furthermore, a fourth arc-shaped groove 28 is formed in the other axial end face 20c at a position closer to the outer periphery of the second shaft 20 on the side opposite to the side where the D-cut portion 19g of the large-diameter portion 19e of the first shaft 19 is provided. The fourth arc-shaped groove 28 is concentric with the outer periphery of the second shaft 20. The fourth arc-shaped groove 28 has the same shape as the second arc-shaped groove 24, but is provided at a position further outward than the second arc-shaped groove 24 in the radial direction of the first shaft 19. The positional relationship between the fourth arc-shaped groove 28 and a fourth protrusion 35 (described later) when the second torsion spring 17 is in the neutral position is the same as the positional relationship between the second arc-shaped groove 24 and a second protrusion 32 (described later) when the first torsion spring 16 is in the neutral state (the positional relationship shown in FIG. 3).

[0027] The connecting member 13 is cylindrically formed from a metal material or resin. The connecting member 13 includes a small-diameter cylindrical portion 13a, a large-diameter cylindrical portion 13b, and a connecting portion 13c that connects the small-diameter cylindrical portion 13a and the large-diameter cylindrical portion 13b. A first small-diameter portion 19c of the first shaft 19 penetrates the space inside the inner circumferential surface of the small-diameter cylindrical portion 13a. The inner circumferential surface of the small-diameter cylindrical portion 13a is separated from the outer circumferential surface of the first small-diameter portion 19c by a small gap. A D-shaped portion (not shown) is formed on the outer circumferential surface of the small-diameter cylindrical portion 13a, and the D-shaped portion is fixed to the first through-hole 20a of the second shaft 20 via a known key connection. Note that instead of a known key connection, a known screw connection may be used to fix the first through-hole 20a of the second shaft 20 to the D-shaped portion of the small-diameter cylindrical portion 13a. Moreover, instead of the D-cut portion, the first through-hole 20a of the second shaft 20 may be fixed to the small diameter cylindrical portion 13a via a spline portion.

[0028] The large-diameter cylindrical portion 13b has a cylindrical shape with a larger diameter than the small-diameter cylindrical portion 13a. The large-diameter cylindrical portion 13b accommodates the medium-diameter portion 19d, the large-diameter portion 19e, a part of the second small-diameter portion 19f of the first shaft 19, and the first torsion spring 16. An axial end portion of the large-diameter cylindrical portion 13b on the one end 19a side is connected to an axial end portion of the small-diameter cylindrical portion 13a on the other end 19b side by a connecting portion 13c. Meanwhile, the open surface of the other axial end portion of the large-diameter cylindrical portion 13b on the other end 19b side is covered by a connecting member cover 14.

[0029] The coupling portion 13c has a first annular extension portion 13d that extends radially outward from the outer periphery of the small-diameter cylindrical portion 13a on the first shaft 19, a cylindrical protruding portion 13e that protrudes from a radial end of the first annular extension portion 13d toward the other end 19b, and a second annular extension portion 13f that extends radially outward from the outer periphery of the cylindrical protruding portion 13e on the first shaft 19. The space inside the inner circumferential surface of the cylindrical protruding portion 13e forms a first bearing receiving portion 29 that receives a second ball bearing 22 that rotatably supports the first small-diameter portion 19c. When the second ball bearing 22 is received in the first bearing receiving portion 29, an end face 22b of an inner race 22a of the second ball bearing 22 on the other end 19b side abuts an end face 19k of the medium-diameter portion 19d on the one end 19a side.

[0030] A first protrusion 30 (shown by solid and dashed lines in FIG. 2) is formed on a surface 13g on the other end 19b side of the second annular expansion portion 13f near the first arc-shaped groove 23 of the large-diameter portion 19e of the first shaft 19, protruding toward the large-diameter portion 19e. More specifically, as shown in FIG. 3, the first protrusion 30 is provided adjacent to the second center line X2 in an area to the left of the first center line X1 and above the second center line X2. As shown in FIG. 3, the first protrusion 30 is adjacent to the first groove end 23a of the first arc-shaped groove 23 when the first torsion spring 16 is in the neutral position. The width of the first protrusion 30 along the radial direction of the first shaft 19 is greater than the width of the first arc-shaped groove 23 along the radial direction of the first shaft 19. The first protrusion 30 has a first flat surface 30a along the second center line X2, a second flat surface 30b on the opposite side of the first flat surface 30a in the circumferential direction of the first shaft 19, a first arcuate surface 30c connecting inner ends of the first flat surface 30a and the second flat surface 30b, and a second arcuate surface 30d connecting outer ends of the first flat surface 30a and the second flat surface 30b. A first inclined portion 16d of a first spring end 16b (described later) of the first torsion spring 16 can abut against the first flat surface 30a of the first protrusion 30.

[0031] The connecting member lid 14 is formed in a disk shape from a metal material or resin. A second through-hole 14a is formed in the center of the connecting member lid 14 along the axial direction of the first shaft 19. The second through-hole 14a is formed in a stepped shape that decreases in diameter from one end 19a to the other end 19b via a continuous annular step 14b. The space closer to the one end 19a than the step 14b serves as a second bearing accommodating portion 31 that accommodates a third ball bearing 25 that rotatably supports the second small-diameter portion 19f of the first shaft 19. A continuous annular step 14c is formed on the outer peripheral edge of the connecting member lid 14 on the one end 19a side. The other axial end of the large-diameter cylindrical portion 13b of the connecting member 13 on the other end 19b side is fixed to the step 14c. The surface of the connecting member cover 14 on the other end 19b side facing the closing member 18 is separated from the surface 18b of the closing member 18 on the one end 19a side via a small gap.

[0032] Furthermore, a second protrusion 32 (shown by solid and dashed lines in FIG. 2 ) is formed on the surface 14d on the one end 19a side of the connecting member cover 14 near the second arc-shaped groove 24 of the large-diameter portion 19e of the first shaft 19, protruding toward the large-diameter portion 19e. More specifically, as shown in FIG. 3 , the second protrusion 32 is provided adjacent to the second center line X2 in an area to the right of the first center line X1 and above the second center line X2. As shown in FIG. 3 , the second protrusion 32 is adjacent to the third groove end 24a of the second arc-shaped groove 24 when the first torsion spring 16 is in the neutral position. The second protrusion 32 has a shape similar to that of the first protrusion 30. The width of the second protrusion 32 along the radial direction of the first shaft 19 is greater than the width of the second arc-shaped groove 24 along the radial direction of the first shaft 19. The second protrusion 32 has a third flat surface 32a along the second center line X2, a fourth flat surface 32b on the opposite side of the third flat surface 32a in the circumferential direction of the first shaft 19, a third arcuate surface 32c connecting the inner ends of the third flat surface 32a and the fourth flat surface 32b, and a fourth arcuate surface 32d connecting the outer ends of the third flat surface 32a and the fourth flat surface 32b. A second inclined portion 16f of a second spring end portion 16c (described later) of the first torsion spring 16 can abut against the third flat surface 32a of the second protrusion 32.

[0033] The housing 15 has a first housing 33 located on the other end 19b side and a second housing 34 located on the one end 19a side.

[0034] The first housing 33 is made of metal or resin and has a cylindrical shape with a bottom. The first housing 33 accommodates a portion of the first shaft 19 closer to the other end 19b than the second ball bearing 22, a portion of the coupling portion 13c and the large-diameter cylindrical portion 13b of the connecting member 13, the first torsion spring 16, and the connecting member cover 14. The first housing 33 has a circular, plate-shaped bottom wall portion 33a and a cylindrical peripheral wall portion 33b extending from the outer periphery of the bottom wall portion 33a toward the other end 19b. A third through hole 33c is formed in the center of the bottom wall portion 33a along the axial direction of the first shaft 19. The coupling portion 13c of the connecting member 13, with the first small-diameter portion 19c of the first shaft 19 passing through it, is inserted into the third through hole 33c. The inner circumferential surface of the third through hole 33c is spaced from the outer circumferential surface of the coupling portion 13c. In addition, a fourth protrusion 35 (shown by solid and dashed lines in Figure 2) is formed on the surface 33d on the one end 19a side of the bottom wall portion 33a at a position near the fourth arc groove 28 of the second shaft 20, protruding toward the second shaft 20 side.

[0035] The second housing 34 is made of metal or resin and has a cylindrical shape with a bottom. The second housing 34 accommodates a part of the first small diameter portion 19c of the first shaft 19, the small diameter cylindrical portion 13a of the connecting member 13, the second shaft 20, and the second torsion spring 17. The second housing 34 has a bottom wall 34a, a cylindrical peripheral wall 34b extending from the outer periphery of the bottom wall 34a toward the other end 19b, and a cylindrical extension 34c extending from the center of the bottom wall 34a toward the dial 1. A third protrusion 36 (shown by solid and dashed lines in FIG. 2) is formed on a surface 34d on the other end 19b side of the bottom wall 34a near the third arcuate groove 27 of the second shaft 20, protruding toward the second shaft 20. Furthermore, an annular flange portion 34e is formed on the axial end portion of the peripheral wall portion 34b on the other end portion 19b side so as to protrude radially outward from the first shaft 19. This flange portion 34e is attached and fixed to the bottom wall portion 33a of the first housing 33 via a fixing member (not shown), for example, a bolt.

[0036] A fourth through-hole 34f is formed through the bottom wall 34a and the expanded portion 34c in the axial direction of the first shaft 19. The first small-diameter portion 19c of the first shaft 19 is inserted into the fourth through-hole 34f. A third bearing accommodating portion 37, which is a circular recess recessed from the surface 34d of the bottom wall 34a toward the one end 19a, is formed in the bottom wall 34a and a portion of the expanded portion 34c. A first ball bearing 21 that rotatably supports the first small-diameter portion 19c of the first shaft 19 is accommodated in the third bearing accommodating portion 37. A continuous annular groove 34g is formed in the inner circumferential surface of the expanded portion 34c at a position closer to the one end 19a than the first ball bearing 21. An O-ring 38, which serves as a sealing member, is provided in the annular groove 34g. The O-ring 38 provides a seal between the inner circumferential surface of the expanded portion 34c of the second housing 34 and the outer circumferential surface of the first small diameter portion 19c of the first shaft 19. Furthermore, the O-ring 38 generates a viscous sensation due to friction with the first shaft 19 when the dial 1 begins to be turned, and this viscous sensation gives the driver the sensation of operating the dial 1. Note that the sealing member does not have to be the O-ring 38 as long as it provides a seal between the inner circumferential surface of the expanded portion 34c of the second housing 34 and the outer circumferential surface of the first small diameter portion 19c of the first shaft 19; for example, an oil seal or a dust seal may be provided. Furthermore, the oil seal or dust seal may be provided in combination with the O-ring 38.

[0037] The first torsion spring 16 is a linear spring that is attached to the large diameter portion 19e of the first shaft 19 via the first arcuate groove 23 and the second arcuate groove 24 of the first shaft 19 when no preload is applied. The first torsion spring 16 has a helical portion 16a formed by helically winding a thin, cylindrical metal member, a hook-shaped first spring end 16b at one end of the helical portion 16a, and a hook-shaped second spring end 16c at the other end of the helical portion 16a. The first torsion spring 16 is arranged so that the large diameter portion 19e of the first shaft 19 is inserted inside the helical portion 16a. 2, the first spring end 16a has a first inclined portion 16d inclined from one axial end of the helical portion 16a toward the first arc-shaped groove 23 of the first shaft 19, and a first bent portion 16e bent from the tip of the first inclined portion 16d into the first arc-shaped groove 23. The second spring end 16c has a similar shape to the first spring end 16a, and has a second inclined portion 16f inclined from the other axial end of the helical portion 16a toward the second arc-shaped groove 24 of the first shaft 19, and a second bent portion 16g bent from the tip of the second inclined portion 16f into the second arc-shaped groove 24.

[0038] The reaction force due to the torsion of first torsion spring 16 is generated by position switching mechanism 39 shown in Figures 3 to 5. Position switching mechanism 39 has first arcuate groove 23 and second arcuate groove 24 of first shaft 19, first bent portion 16e and second bent portion 16g of first torsion spring 16 that are inserted into first arcuate groove 23 and second arcuate groove 24, respectively, first protrusion 30 of connecting member 13, and second protrusion 32 of connecting member cover 14. Position switching mechanism 39 switches first spring end 16b or second spring end 16c of first shaft 19 between the unlocked position and the locked position when first shaft 19 rotates in response to operation of dial 1. That is, the position switching mechanism 39 switches the position of the first bent portion 16e inserted into the first arcuate groove 23 or the second bent portion 16g inserted into the second arcuate groove 24 from a fixed position to an unlocked position depending on the rotation direction of the first shaft 19. This position switching mechanism 39 causes the first torsion spring 16 to apply a biasing force to the first shaft 19 regardless of the rotation direction of the first shaft 19. That is, the position switching mechanism 39 causes the first torsion spring 16 to apply a biasing force to the first shaft 19 in response to either the clockwise rotation direction or the counterclockwise rotation direction of the first shaft 19.

[0039] 3, when the first torsion spring 16 is in the neutral position, the position switching mechanism 39 fixes both the first bent portion 16e and the second bent portion 16g of the first torsion spring 16 in the fixed position. More specifically, the position of the first bent portion 16e is fixed by a first inclined portion 16d formed integrally with the first bent portion 16e of the first spring end portion 16a abutting against the first flat surface 30a of the first protrusion 30 of the connecting member 13. Meanwhile, the position of the second bent portion 16g is fixed by a second inclined portion 16f formed integrally with the second bent portion 16g of the second spring end portion 16c abutting against the third flat surface 32a of the second protrusion 32 of the connecting member cover 14. The above-mentioned "neutral position" refers to a neutral position in which the dial 1 is not rotated to either the right (right turning) or the left (left turning) relative to the vehicle's direction of travel, and therefore the first torsion spring 16 is not twisted in either the right or left direction of rotation.

[0040] Furthermore, when the first shaft 19 rotates to the right (clockwise in FIG. 3) in conjunction with the clockwise rotation of the dial 1, as shown in FIG. 4, while the first inclined portion 16d remains in contact with the first flat surface 30a of the first protrusion 30, the second bent portion 16g is pushed by the third groove end portion 24a of the second arcuate groove 24 rotating to the right, and is twisted to the non-fixed position, that is, to a position spaced apart in the clockwise rotation direction from the third flat surface 32a of the second protrusion 32. As a result, a reaction force (biasing force) is generated in the counterclockwise rotation direction, which is opposite to the clockwise rotation direction of the first shaft 19.

[0041] On the other hand, when the first shaft 19 rotates to the left (counterclockwise in FIG. 3) in conjunction with the left rotation of the dial 1, as shown in FIG. 5, while the second bent portion 16g remains in contact with the third flat surface 32a of the second protrusion 32, the first bent portion 16e is pushed by the first groove end portion 23a of the first arcuate groove 23 rotating to the left, and is twisted to the non-fixed position, that is, to a position spaced apart in the left rotation direction from the first flat surface 30a of the first protrusion 30. This generates a reaction force in the right rotation direction, which is opposite to the left rotation direction of the first shaft 19.

[0042] When the first torsion spring 16 configured in this manner reaches a predetermined load due to the rotation of the first shaft 19, the connecting member 13 begins to rotate in the same direction as the rotation of the first shaft 19 through the abutment between the first protrusion 30 and the first inclined portion 16d or the abutment between the second protrusion 32 and the second inclined portion 16f. Here, the "predetermined load" is a load generated by the preload set in the second torsion spring 17. As shown in FIG. 6 , in this embodiment, the predetermined load is set to approximately 0.17 Nm and is reached when the operating angle of the dial 1 is 60 degrees. Furthermore, as the connecting member 13 rotates, the second shaft 20 fixed to the outer periphery of the connecting member 13 also begins to rotate. At this time, the first shaft 19 continues to rotate even after the second shaft 20 has rotated. First torsion spring 16 continues to apply a biasing force to first shaft 19 even after the biasing force of second torsion spring 17 has been applied to second shaft 20. Note that instead of configuring first torsion spring 16 and second torsion spring 17 in this manner, a configuration may be used in which, even if the rotation of first torsion spring 16 applying a biasing force to first shaft 19 stops during rotation of dial 1, a switching device (not shown) applies a biasing force to shaft 4 only by second torsion spring 17, in other words, a configuration in which first torsion spring 16 applies a biasing force to first shaft 19 and then second torsion spring 17 applies a biasing force to second shaft 20.

[0043] The second torsion spring 17 has the same spring constant as the first torsion spring 16 and is a linear spring that is attached to the second shaft 20 via the third arcuate groove 27 and the fourth arcuate groove 28 of the second shaft 20 in a preloaded state. The second torsion spring 17 has a helical portion 17a formed by helically winding a thin, cylindrical metal member, a third spring end 17b which is one end of the helical portion 17a, and a fourth spring end 17c which is the other end of the helical portion 17a. The second torsion spring 17 is arranged so that the second shaft 20 is inserted inside the helical portion 17a. 2, third spring end 17b has third inclined portion 17d inclined from one axial end of helical portion 17a toward third arc-shaped groove 27 of second shaft 20, and third bent portion 17e bent from the tip of third inclined portion 17d into third arc-shaped groove 27. Fourth spring end 17c has a shape similar to third spring end 17b, and has fourth inclined portion 17f inclined from the other axial end of helical portion 17a toward fourth arc-shaped groove 28 of second shaft 20, and fourth bent portion 17g bent from the tip of fourth inclined portion 17f into fourth arc-shaped groove 28. The reaction force due to the torsion of second torsion spring 17 is generated by a position switching mechanism similar to position switching mechanism 39 applied to first torsion spring 16. The position switching mechanism applied to second torsion spring 17 includes third arc-shaped groove 27 and fourth arc-shaped groove 28 of second shaft 20, third bent portion 17e and fourth bent portion 17g of second torsion spring 17 inserted into third arc-shaped groove 27 and fourth arc-shaped groove 28, respectively, third protrusion 36 of second housing 34, and fourth protrusion 35 of first housing 33. The position switching mechanism switches third spring end 17b or fourth spring end 17c of second shaft 20 between the unlocked position and the locked position when second shaft 20 rotates in conjunction with the rotation of first shaft 19. In other words, the position switching mechanism switches the position of third bent portion 17e inserted into third arc-shaped groove 27 or fourth bent portion 17g inserted into fourth arc-shaped groove 28 from the locked position to the unlocked position depending on the rotation direction of second shaft 20.The mechanism for switching the position of the position switching mechanism for the second torsion spring 17 is similar to the mechanism for switching the position of the position switching mechanism 39 for the first torsion spring 16, i.e., the switching style described above with reference to Figures 4 and 5. The position switching mechanism for the second torsion spring 17 causes the second torsion spring 17 to apply a biasing force to the second shaft 20 regardless of the direction of rotation of the second shaft 20.

[0044] Furthermore, a rotary damper mechanism (not shown) may be provided at any position on the first shaft 19. This reduces the rotational speed of the first shaft 19, thereby slowing the torsional speed of the first torsion spring 16, thereby applying a damping force to the first torsion spring 16. This rotary damper mechanism is a well-known rotary damper mechanism that utilizes the viscous resistance of oil, and includes a case, a rotor housed in the case together with oil, and a cap that covers the case and has a shaft through-hole through which the rotor shaft passes. Note that when the rotational speed of the first shaft 19 is increased (turned further), the oil may be throttled. Furthermore, when the first shaft 19 is rotated in one rotational direction and then turned back to the other rotational direction (turned back), the oil may be bypassed via a flow path provided in the rotary damper mechanism.

[0045] Here, the two-stage spring characteristics using first torsion spring 16 and second torsion spring 17 will be described with reference to Fig. 6. First, the spring constant of first torsion spring 16 is defined as "K1," while the spring constant of second torsion spring 17 is defined as "K2." As shown in Fig. 6, when the steering angle is from 0 degrees to less than 60 degrees (small steering angle region), the biasing force of only first torsion spring 16 acts on shaft 4, so the steering force applied to shaft 4 increases linearly against a reaction force based on the spring constant K1 (operating force gain K1). Then, when the operating angle reaches 60 degrees and the operating force reaches a predetermined load, approximately 0.17 Nm in this embodiment, the biasing force of second torsion spring 17 acts in addition to the biasing force of first torsion spring 16, so the composite spring constant K obtained by regarding first torsion spring 16 and second torsion spring 17 as being connected in series can be obtained from the formula "1 / K = 1 / K1 + 1 / K2". As described above, the spring constant of first torsion spring 16 and the spring constant of second torsion spring 17 in this embodiment are the same, so the formula "1 / K = 2 / K1" holds, and rearranging this formula gives "K = K1 / 2". Therefore, in this embodiment, when the steering angle is in the range of 60 degrees to 180 degrees (large steering angle region), the operating force applied to the shaft 4 increases linearly against a reaction force based on the composite spring constant K1 / 2 (operating force gain K1 / 2). That is, as shown in FIG. 6, the operating force in the large steering angle region increases linearly at half the increase rate of the operating force in the small steering angle region. Therefore, in the large steering angle region, the dial 1 is operated with half the force required in the small steering angle region. Note that, although an example has been shown in which the spring constants of the first torsion spring 16 and the second torsion spring 17 are the same, the spring constants may be different depending on the desired reaction force characteristics.

[0046] The closing member 18 is formed into a disk shape from a metal material or resin. One end 19a of the closing member 18 is fixed to the other axial end 19b of the first housing 33. A fourth bearing accommodating portion 40 is formed in the center of the surface 18b of the closing member 18 on the one end 19a side, recessed from the surface 18b toward the other end 19b. A fourth ball bearing 26 is accommodated in the fourth bearing accommodating portion 40, which rotatably supports the stepped reduced diameter portion 19j provided in the second small diameter portion 19f.

[0047] In the present embodiment, the first torsion spring 16 is attached to the large diameter portion 19e of the first shaft 19 via the first arcuate groove 23 and the second arcuate groove 24 of the first shaft 19 without any preload applied. However, taking into consideration friction between the first torsion spring 16 and the large diameter portion 19e of the first shaft 19 caused by a seal member provided in the annular groove 34g, the first torsion spring 16 may be attached to the large diameter portion 19e of the first shaft 19 with a preload corresponding to the torque resulting from the friction. When friction (viscous feeling) is applied between the first torsion spring 16 and the first shaft 19 by the seal member, the first torsion spring 16 becomes less likely to return to the neutral position. Therefore, applying a preload corresponding to the torque resulting from the friction prevents the first torsion spring 16 from becoming less likely to return to the neutral position. This improves the driver's feel when operating the dial (steering feel).

[0048] [Advantages of the first embodiment] As described above, in the first embodiment, first torsion spring 16 generates a biasing force in the direction opposite to the rotational direction of first shaft 19, regardless of the rotational direction of first shaft 19. In other words, first torsion spring 16 applies a biasing force in the counterclockwise direction when first shaft 19 rotates clockwise, and applies a biasing force in the clockwise direction when first shaft 19 rotates counterclockwise. More specifically, compared to the conventional technology in which dedicated springs that are biasing members are provided to apply biasing forces (reaction forces) in each rotational direction of the shaft, this embodiment provides a shared first torsion spring 16 that generates biasing forces in both rotational directions. This reduces the number of springs compared to the conventional technology, thereby reducing the manufacturing costs of the steering operation input device.

[0049] Furthermore, in the prior art, a single spring is provided to apply a biasing force when the shaft rotates to the right, and another single spring is provided to apply a biasing force when the shaft rotates to the left. This creates a problem in that the biasing force differs between the right and left rotation of the shaft due to individual differences between the two springs.

[0050] However, in this embodiment, the common first torsion spring 16 applies a biasing force when the first shaft 19 is rotated both clockwise and counterclockwise, so that the difference in biasing force between clockwise and counterclockwise rotations can be eliminated.

[0051] In addition, in the prior art, the switching of each spring between when the shaft is rotating to the right and when it is rotating to the left is performed via a linear motion conversion device that converts the rotational force input from the steering operation input member into linear movement.

[0052] However, in this embodiment, the common first torsion spring 16 applies a biasing force when the first shaft 19 rotates in both directions, so there is no need for a linear motion conversion device as in the prior art. Therefore, compared to the prior art, it is possible to reduce the manufacturing costs and assembly time of the steering operation input device by the amount of the linear motion conversion mechanism.

[0053] Furthermore, in this embodiment, a configuration may be used in which first torsion spring 16 applies a biasing force to first shaft 19, and then second torsion spring 17 applies a biasing force to second shaft 20. In this case, even if the rotation of first torsion spring 16 applying a biasing force to first shaft 19 stops, the switching device will cause only second torsion spring 17 to apply a biasing force to shaft 4. Therefore, even if first torsion spring 16 fails, the second torsion spring 17 can apply a biasing force to shaft 4, allowing the steering operation input device to continue operating.

[0054] Furthermore, in this embodiment, first torsion spring 16 continues to apply a biasing force to first shaft 19 even after the biasing force of second torsion spring 17 is applied to second shaft 20. In this case, there is no need for a switching device as in the above-described configuration in which first torsion spring 16 applies a biasing force to first shaft 19 and then second torsion spring 17 applies a biasing force to second shaft 20, and therefore the steering operation input device can be manufactured more easily than with the above-described configuration.

[0055] Furthermore, in this embodiment, the steering operation input device has a position switching mechanism 39 that switches the first bent portion 16e of the first spring end 16a of the first torsion spring 16 or the second bent portion 16g of the second spring end 16c between an unlocked position and a locked position when the first shaft 19 rotates. Therefore, unlike the prior art, where a linear motion member is not moved over a relatively long distance by a linear motion conversion mechanism, a biasing force in the opposite direction to the rotation of the first shaft 19 can be easily applied by simply switching the position of the first bent portion 16e or the second bent portion 16g in response to the rotation of the first shaft 19. Furthermore, while in the prior art, the load from the spring and the linear motion conversion mechanism acts on the shaft, in this embodiment, only the load from the first torsion spring 16 or the second torsion spring 17 acts on the first shaft 19, etc. Therefore, the load on the steering operation input device can be reduced.

[0056] In addition, in the conventional technology, two coil springs are arranged along the axial direction of the shaft, and then a linear motion conversion mechanism is provided. Furthermore, in the conventional technology, the steering operation input device needs to be designed taking into account the stroke of the coil springs along the axial direction of the shaft, which tends to result in a larger steering operation input device.

[0057] However, in this embodiment, first torsion spring 16 and second torsion spring 17 are used as the biasing members. First torsion spring 16 and second torsion spring 17 expand relatively little after deformation, and generate a biasing force simply by twisting the spring in the circumferential direction, so the dimension of the steering operation input device along the axial direction of first shaft 19 can be made shorter than in the prior art.

[0058] Furthermore, in order to shorten the axial dimension of the steering operation input device, it is possible to arrange two coil springs in series and arrange a direct-acting conversion mechanism radially outside these coil springs (see Figure 7). However, in this embodiment, no direct-acting conversion mechanism is required, so the steering operation input device can be made smaller along the radial direction of the first shaft 19 compared to the steering operation input device of the second embodiment described below.

[0059] In this embodiment, shaft 4 has first shaft 19 provided with first torsion spring 16 and second shaft 20 provided with second torsion spring 17, and connecting member 13 covering first shaft 19 and first torsion spring 16 is provided radially outward of first shaft 19. Connecting member 13 is connected to first shaft 19 via first torsion spring 16 and is also connected to second shaft 20. Connecting member 13 rotates when first torsion spring 16 reaches a predetermined load. As connecting member 13 rotates, second shaft 20 rotates, thereby twisting second torsion spring 17 provided on second shaft 20. Therefore, until first torsion spring 16 reaches a predetermined load, a biasing force based only on first torsion spring 16 is generated, and after first torsion spring 16 reaches the predetermined load, a biasing force based on first torsion spring 16 and second torsion spring 17 is generated. As a result, as shown in FIG. 6, the operating force of dial 1 changes in two stages, with an operating angle of 60 degrees in between. In other words, the operating force increases at a predetermined rate (gradient of increase) until the operating angle reaches 60 degrees, but after 60 degrees, it increases at half the rate compared to when the operating angle is less than 60 degrees. Therefore, in the large steering angle range after the operating angle is 60 degrees, it is possible to reduce the driver's steering fatigue and suppress a decrease in vehicle maneuverability.

[0060] Furthermore, in this embodiment, the predetermined load is a load generated by a preload set in the second torsion spring 17. Therefore, by changing the preload, it is possible to adjust the time point at which the operating force changes.

[0061] Furthermore, in this embodiment, the outer diameter of first shaft 19 is set to be smaller than the inner diameter of first torsion spring 16 when first torsion spring 16 generates a biasing force and is deformed. This makes it possible to prevent first torsion spring 16 and first shaft 19 from being damaged due to the deformed first torsion spring 16 coming into contact with the outer peripheral surface of first shaft 19. Furthermore, it is possible to prevent first shaft 19 from stopping its rotation due to the deformed first torsion spring 16 coming into contact with the outer peripheral surface of first shaft 19.

[0062] Furthermore, in this embodiment, a D-cut portion is formed on the outer peripheral surface of the small-diameter cylindrical portion 13a of the connecting member 13, and the connecting member 13 is fixed to the first through-hole 20a of the second shaft 20 via the D-cut portion. Therefore, when assembling the second shaft 20 to the connecting member 13, the D-cut portion makes it easy to position the second shaft 20, particularly the third arc groove 27.

[0063] In this embodiment, the connecting member 13 and the second shaft 20 may be fixed to each other via a spline portion. Therefore, even when a large rotational torque is generated in the connecting member 13, the connecting member 13 and the second shaft 20 can be firmly fixed to each other.

[0064] Furthermore, in this embodiment, an O-ring 38, which is a sealing member, is provided in the annular groove 34g of the second housing 34. The O-ring 38 seals between the inner circumferential surface of the expanded portion 34c of the second housing 34 and the outer circumferential surface of the first small diameter portion 19c of the first shaft 19. As a result, the first shaft 19 rotates against the frictional force of the O-ring 38, which creates a viscous feeling when the dial 1 starts to be turned. This improves the operation feel (steering feel) of the dial for the driver.

[0065] In this embodiment, a damper mechanism that applies a damping force to first torsion spring 16 may be provided at any position on first shaft 19. In this case, the biasing force of first torsion spring 16 is damped, thereby reducing the force required by the driver to operate dial 1 and reducing driver fatigue.

[0066] [Second embodiment] Fig. 7 is a vertical cross-sectional view of the steering operation input device of the second embodiment, showing the steering operation input device in the neutral position.

[0067] The steering operation input device of the second embodiment includes a rotational-linear motion converter 41, a housing 42, a connecting portion 43, a reaction force generator 44, a first blocking cover member 45, a second blocking cover member 46, a third blocking cover member 47, and a fourth blocking cover member 48. In this steering operation input device, a rotational force input to a third shaft 49 (described later) is converted into linear motion by the rotational-linear motion converter 41, and this linear motion is transmitted to the reaction force generator 44 via the connecting portion 43. The reaction force generator 44 transmits the biasing forces of a first coil spring 81 and a second coil spring 82 (described later) that are biased in accordance with the transmitted linear motion to the rotational-linear motion converter 41 via the connecting portion 43.

[0068] The rotary-linear motion conversion unit 41 has a third shaft 49 and a linear motion conversion mechanism 50 which is a ball screw mechanism provided on the outer periphery of the third shaft 49 .

[0069] The third shaft 49 has a first small-diameter cylindrical portion 49c located on one end 49a side, a medium-diameter cylindrical portion 49d formed integrally with the first small-diameter cylindrical portion 49c and having a larger diameter than the first small-diameter cylindrical portion 49c, a large-diameter cylindrical portion 49e formed integrally with the medium-diameter cylindrical portion 49d and having a larger diameter than the medium-diameter cylindrical portion 49d, and a second small-diameter cylindrical portion 49f formed integrally with the large-diameter cylindrical portion 49e and having a smaller diameter than the large-diameter cylindrical portion 49e. The first small-diameter cylindrical portion 49c has a D-cut portion 49g formed therein for fixing to a dial (not shown) through which steering operation is input. A fifth ball bearing 51, which rotatably supports the medium-diameter cylindrical portion 49d, and an O-ring 38, which serves as a sealing member, are provided on the outer periphery of the medium-diameter cylindrical portion 49d. As in the first embodiment, the sealing member does not have to be the O-ring 38, and an oil seal or a dust seal, for example, may be provided. The oil seal or dust seal may also be used in combination with the O-ring 38. A linear motion conversion mechanism 50 is provided on the outer periphery of the large-diameter cylindrical portion 49e. The linear motion conversion mechanism 50 converts the rotational force input to the third shaft 49 from a dial (not shown) into linear motion along the axial direction of the third shaft 49. The linear motion conversion mechanism 50 will be described in detail later. A sixth ball bearing 52, which rotatably supports the second small-diameter cylindrical portion 49f, is provided on the outer periphery of the second small-diameter cylindrical portion 49f.

[0070] The linear motion conversion mechanism 50 includes a shaft-side ball screw groove 49h, which is a helical groove formed on the outer peripheral surface of the large-diameter cylindrical portion 49e of the third shaft 49; a nut-side ball screw groove 53a, which is a helical groove formed on the inner peripheral surface of a nut 53, which is a linear motion member; a plurality of balls 54 arranged between the ball screw grooves 49h and 53a; a restricting member 55 that restricts rotation of the nut 53 in the rotational direction of the third shaft 49 and allows movement of the nut 53 along the axial direction of the third shaft 49; and a cap member 56 that holds the nut 53 against the restricting member 55. The balls 54 support the nut 53 so that it can rotate relative to the large-diameter cylindrical portion 49e of the third shaft 49. The nut 53 has an annular protrusion 53b that protrudes radially outward from its outer peripheral surface. The annular protrusion 53b is located near the axial end of the nut 53 on the one end 49a side. The restricting member 55 is formed in a cylindrical shape with a bottom, and is disposed in a position where the bottom 55a is located on the other end 49b side. A restricting member through-hole 55b is formed in the bottom of the restricting member 55, penetrating along the axial direction of the third shaft 49. The large-diameter cylindrical portion 49e of the third shaft 49 is inserted into the restricting member through-hole 55b. The restricting member 55 is fixed to the nut 53 with an axial end 55c on the one end 49a side of the restricting member 55 abutting a first abutment surface 53b on the other end 49b side of the annular protrusion 53b of the nut 53. The restricting member 55 is configured to move smoothly along the axial direction of the third shaft 49 by a guide rail (not shown) provided on a converter-side housing portion 57 (described later).

[0071] The cap member 56 is formed in a cylindrical shape with a bottom that is shorter than the restricting member 55, and is disposed in an orientation in which the bottom 56a is located on the one end 49a side. A cap member through-hole 56b is formed in the bottom 56a of the cap member 56 and penetrates in the axial direction of the third shaft 49. The large-diameter cylindrical portion 49e of the third shaft 49 is inserted into the cap member through-hole 56b. In addition, a female thread portion (not shown) is provided on the inner peripheral surface of the cap member 56, and this female thread portion is fitted with a male thread portion (not shown) provided on the outer peripheral surface of the nut 53, thereby pressing the annular protrusion 53b of the nut 53 against the axial end 55c of the restricting member 55.

[0072] Furthermore, instead of the linear motion conversion mechanism 50, which is the above-described ball screw mechanism, a linear motion conversion mechanism using thread engagement may be applied to the steering operation input device of this embodiment. In this case, this linear motion conversion mechanism has a first helical uneven portion (male thread portion) formed on the outer peripheral surface of the third shaft 49 and a second helical uneven portion (female thread portion) that engages with the first uneven portion, and has a nut that is a movable member that can move in the axial direction of the third shaft 49 in response to rotation of a dial (not shown), and a restricting member that restricts rotation of the nut in the rotational direction of the third shaft 49 and allows movement of the nut along the axial direction of the third shaft 49.

[0073] The housing 42 has a converter-side housing portion 57 that is generally cylindrical and has a bottom, and that houses a portion of the third shaft 49 and the linear motion conversion mechanism 50, and a generator-side housing portion 58 that is generally cylindrical and is located radially outward of the converter-side housing portion 57 and houses the reaction force generator 44. As shown in FIG. 7 , the housing 42 is configured by joining a portion of the outer periphery of the converter-side housing portion 57 to a portion of the outer periphery of the generator-side housing portion 58, and then providing a communication portion 59 at this joint that communicates the interior of the converter-side housing portion 57 with the interior of the generator-side housing portion 58.

[0074] The opening of the converter-side housing 57 on the one end 49a side is closed by a first closing cover member 45. The first closing cover member 45 is cylindrical and has a cover member through-hole 45a in its center. A medium-diameter cylindrical portion 49d and a large-diameter cylindrical portion 49e of the third shaft 49 are inserted into the cover member through-hole 45a. The inner circumferential surface of the cover member through-hole 45a has a first inner circumferential surface portion 45c adjacent to the cover member end 45b on the one end 49a side of the cover member through-hole 45a, a second inner circumferential surface portion 45e connected to the first inner circumferential surface portion 45c via a first step portion 45d and having a smaller diameter than the first inner circumferential surface portion 45c, and a third inner circumferential surface portion 45g connected to the second inner circumferential surface portion 45e via a second step portion 45f and having a smaller diameter than the second inner circumferential surface portion 45e. The space inside the first inner circumferential surface portion 45c is an O-ring receiving portion 60 that receives an O-ring 38. The space inside the second inner circumferential surface portion 45e is a fifth bearing receiving portion 85 that receives a fifth ball bearing 51 that rotatably supports the medium-diameter cylindrical portion 49d of the third shaft 49. A ring-shaped cover member-side annular protrusion 45i that protrudes from the surface 45h toward the other end 49b is formed on the surface 45h of the first block cover member 45 at a position adjacent to the third inner circumferential surface portion 45g. A ring-shaped cover member-side annular recess 45j that is recessed from the surface 45h toward the one end 49a is formed on the surface 45h of the first block cover member 45 at a position adjacent to the cover member-side annular protrusion 45i.

[0075] A first stopper rubber 61 made of rubber is provided on the outer periphery of the lid member side annular protrusion 45i and the lid member side annular recess 45j, and the first stopper rubber 61 reduces the impact of the cap member 56 against the lid member side annular protrusion 45i and the resulting hitting noise when the nut 53 of the linear motion conversion mechanism 50 moves toward the one end 49a along the axial direction of the third shaft 49. The first stopper rubber 61 has a cylindrical first cylindrical main body 61a and an annular first protruding portion 61b protruding radially outward from the outer periphery on the one end 49a side of the first cylindrical main body 61a. The first stopper rubber 61 is disposed on the outer periphery of the cover member-side annular recess 45j such that the first protruding portion 61b is located within the cover member-side annular recess 45j and the tip of the first cylindrical main body 61a is closer to the other end 49b than the first protruding portion surface 45k on the other end 49b side of the cover member-side annular recess 45i. The first stopper rubber 61 is attached to the first block cover member 45 by pressing the first protruding portion 61b toward the one end 49a against the bottom surface of the cover member-side annular recess 45j with the heads of multiple fixing members, for example, bolts 62 (two bolts 62 are shown in this embodiment). The first block cover member 45 further has an annular block member flange 45m that extends radially outward from its outer periphery relative to the third shaft 49. The blocking member flange portion 45m is attached and fixed to the housing flange portion 57a ​​provided on the conversion unit side housing portion 57 by screwing a fixing member, such as a bolt 63, into the flange portion 57a ​​of the conversion unit side housing portion 57 through a fixing member hole 45n provided in the blocking member flange portion 45m.

[0076] Furthermore, a bottom wall 64 is provided integrally with the inner periphery of the converter-side housing 57 at a position inside the converter-side housing 57 facing the linear motion conversion mechanism 50. The bottom wall 64 is formed in a generally cylindrical shape with a bottom wall through-hole 64a in its center. The large-diameter cylindrical portion 49e and the second small-diameter cylindrical portion 49f of the third shaft 49 are inserted into the bottom wall through-hole 64a. The bottom wall through-hole 64a has a first inner surface portion 64c adjacent to a bottom wall end portion 64b located on the one end portion 49a side, and a second inner surface portion 64e connected to the first inner surface portion 64c via a stepped intermediate portion 64d and having a larger diameter than the first inner surface portion 64c. The space inward of the portion of the second inner surface portion 64e adjacent to the stepped intermediate portion 64d serves as a sixth bearing accommodating portion 65 that accommodates a sixth ball bearing 52, which is a bearing that rotatably supports the second small diameter cylindrical portion 49f of the third shaft 49.

[0077] A female thread is formed in a portion of the second inner side surface portion 64e on the other end 49b side, and this female thread is screwed into a male thread provided on the outer peripheral surface of the cup-shaped second block cover member 46. This screwing causes the shaft end surface 46a provided on the second block cover member 46 to press the outer race 52a of the sixth ball bearing 52 against the stepped intermediate portion 64d, thereby fixing the outer race 52a between the bottom wall portion 64 and the second block cover member 46. A male thread is formed in a portion of the outer peripheral surface of the second small-diameter cylindrical portion 49f that is closer to the other end 49b than the sixth ball bearing 52, and this male thread is screwed into a female thread formed on the inner peripheral surface of the ring-shaped pressing member 66. This screw fastening causes a pressing surface 66a provided on one end 49a of the pressing member 66 to press the inner race 52b of the sixth ball bearing 52 against the abutment surface 49i of the large-diameter cylindrical portion 49e, thereby fixing the inner race 52b between the third shaft 49 and the pressing member 66. Furthermore, a circular bottom-wall-side annular protrusion 64g protruding from the surface 64f toward the one end 49a is formed on a surface 64f of the bottom wall 64 on the one end 49a side, at a position adjacent to the first inner side surface portion 64c. Furthermore, a circular bottom-wall-side annular recess 64h recessed from the surface 64f toward the other end 49b is formed on the surface 64f of the bottom wall 64 at a position adjacent to the bottom-wall-side annular protrusion 64g.

[0078] A second stopper rubber 67 made of rubber is provided on the outer periphery of the bottom wall side annular protrusion 64g and the bottom wall side annular recess 64h, and the second stopper rubber 67 reduces the collision of the restricting member 55 with the bottom wall side annular protrusion 64g and the resulting hitting noise when the nut 53 of the linear motion conversion mechanism 50 moves toward the other end 49b along the axial direction of the third shaft 49. The second stopper rubber 67 has a cylindrical second cylindrical main body 67a and an annular second overhang 67b that protrudes radially outward from the outer periphery of the second cylindrical main body 67a on the other end 49b side of the third shaft 49. The second stopper rubber 67 is disposed on the outer periphery of the bottom wall-side annular protrusion 64g such that the second protrusion 67b is located within the bottom wall-side annular recess 64h and the tip of the second cylindrical main body 67a is closer to the one end 49a than the bottom wall end 64b on the one end 49a side of the bottom wall-side annular protrusion 64g. The second stopper rubber 67 is attached to the bottom wall 64 by pressing the second protrusion 67b toward the other end 49b against the bottom surface of the bottom wall-side annular recess 64h with the heads of multiple fixing members, for example, bolts 68 (two bolts 68 are shown in this embodiment).

[0079] The generation unit side housing part 58 is connected to the outer periphery of the conversion unit side housing part 57 by a one end side housing connecting part 42a located on the one end side 49a side and an other end side housing connecting part 42b located on the other end side 49b side. The opening provided on the one end side 49a side of the generation unit side housing part 58 is closed by a third closing lid member 47, while the opening provided on the other end side 49b side is closed by a fourth closing lid member 48.

[0080] A small tube portion 71 having a bottomed cylindrical shape and a diameter smaller than the outer diameter of the generation unit side housing portion 58 is integrally formed on the inner periphery of the generation unit side housing portion 58. The small tube portion 71 has a bottom portion 71a formed at a position closer to the fourth blockage cover member 48 and a peripheral wall portion 71b rising from the outer edge of the bottom portion 71a toward the third blockage cover member 47. The bottom portion 71a is disposed within the generation unit side housing portion 58 so as to be positioned closer to the one end portion 49a than the position of the surface 64f of the bottom wall portion 64 of the conversion unit side housing portion 57 in the axial direction of the third shaft 49. An insertion hole 73c, into which a large shaft portion 77b of a second shaft portion 77 (described later) is inserted, is formed through the center of the bottom portion 71a along the axial direction of the third shaft 49. The surrounding wall portion 71b extends from the outer edge of the bottom portion 71a to near the position of the one-end-side housing coupling portion 42a in the axial direction of the third shaft 49 within the generation unit-side housing portion 58.

[0081] Most of the connecting portion 43 is disposed within the generator-side housing portion 58 and the communication portion 59, and connects the regulating member 55 of the linear motion conversion mechanism 50 to the reaction force generating portion 44. As shown in FIG. 7 , the connecting portion 43 has a first connecting half portion 72 and a second connecting half portion 73 that are provided symmetrically in the axial direction of the third shaft 49. The first connecting half portion 72 and the second connecting half portion 73 are formed by bending a thin plate-shaped member made of a metal material three times.

[0082] The first connecting half 72 has a first fixing portion 72a fixed to the restricting member 55, a first bent piece 72b bent at a right angle from the first fixing portion 72a toward the reaction force generating portion 44, a second bent piece 72c bent at a right angle from one end of the first bent piece 72b toward the third blocking cover member 47, and a third bent piece 72d bent at a right angle from one end of the second bent piece 72c to the opposite side from the first bent piece 72b. A first fixing hole 72e is formed through the first fixing portion 72a, and the first fixing portion 72a is attached and fixed to the restricting member 55 by screwing a fixing member, for example, a bolt 74, into the outer periphery of the restricting member 55 through the first fixing hole 72e. In addition, a first insertion hole 72f is formed near the free end of the third bent piece 72d, penetrating along the axial direction of the third shaft 49, into which a small shaft portion 76a of a first shaft portion 76 described below is inserted.

[0083] The second connecting half 73 has a shape similar to that of the first connecting half 72. The second connecting half 73 has a second fixing portion 73a fixed to the restricting member 55, a fourth bent piece 73b bent at a right angle from the second fixing portion 73a toward the reaction force generating portion 44, a fifth bent piece 73c bent at a right angle from one end of the fourth bent piece 73b toward the fourth blocking cover member 48, and a sixth bent piece 73d bent at a right angle from one end of the fifth bent piece 73c toward the opposite side from the fourth bent piece 73b. A second fixing hole 73e is formed through the second fixing portion 73a, and the second fixing portion 73a is attached and fixed to the restricting member 55 by screwing a fixing member, such as a bolt 75, into the outer periphery of the restricting member 55 through the second fixing hole 73e. 7, a surface of the fourth bent piece 73b located on the one end 49a side is abutted against a surface of the first bent portion 16e of the first connecting half 72 located on the other end 49b side. A second insertion hole 73f is formed near the free end of the sixth bent piece 73d and extends through along the axial direction of the third shaft 49, into which a small shaft portion 77c of a second shaft portion 77 described below is inserted.

[0084] The reaction force generating unit 44 includes a first shaft portion 76, a second shaft portion 77, a first cylindrical guide member 78, a second cylindrical guide member 79, a spring connecting member 80, a first coil spring 81, and a second coil spring 82.

[0085] The first shaft portion 76 has a small diameter small shaft portion 76a located on the third closure cover member 47 side, a central shaft portion 76b formed integrally with the small shaft portion 76a and having a larger diameter than the small shaft portion 76a, and a large shaft portion 76c formed integrally with the central shaft portion 76b and having a larger diameter than the central shaft portion 76b. The first shaft portion 76 is provided radially outward of the third shaft 49 and is arranged in parallel to the third shaft 49. Therefore, the axial direction of the first shaft portion 76 is parallel to the axial direction of the third shaft 49. When the third shaft 49 rotates left, the nut 53 moves toward the other end 49b, and as a result, the first connecting half 72 moves toward the fourth blocking cover member 48.The third bent piece 72d of the first connecting half 72 presses the first pressing surface 76d on the third blocking cover member 47 side of the central shaft portion 76b of the first shaft 76, causing the first shaft 76 to move toward the fourth blocking cover member 48.

[0086] The second shaft portion 77 has a spring accommodating cylindrical portion 77a with a bottom, a large shaft portion 77b protruding from the bottom of the spring accommodating cylindrical portion 77a toward the fourth block cover member 48, a small shaft portion 77c formed integrally with the large shaft portion 77b and having a smaller diameter than the large shaft portion 77b, and a protrusion 77d protruding from the bottom of the spring accommodating cylindrical portion 77a toward the third block cover member 47. The second shaft portion 77 is disposed parallel to the third shaft 49. Therefore, the axial direction of the second shaft portion 77 is parallel to the axial direction of the third shaft 49. When the nut 53 moves toward the other end 49b when the third shaft 49 rotates clockwise, and as a result, the second connecting half 73 moves toward the third blockage cover member 47, the sixth bent piece 73d of the second connecting half 73 presses the second pressing surface 77e on the fourth blockage cover member 48 side of the large shaft portion 77b of the second shaft 77, thereby moving toward the third blockage cover member 47. With the steering operation input device in the neutral position, the tip surface 77f of the protrusion 77d is flush with the axial end surface of the other end 49b side of the regulating member 55 (see Figures 8(c) and 9(a)).

[0087] The first guide cylindrical member 78 slidably guides the center shaft portion 76b of the first shaft portion 76 along the axial direction of the first shaft portion 76. The first guide cylindrical member 78 has a cylindrical first guide tube portion 78a and a circular first annular extension portion 78b that protrudes radially outward from the outer periphery of the axial end portion of the first guide tube portion 78a on the third blockage cover member 47 side. The first guide tube portion 78a is fixed to the surrounding wall portion 71b by press-fitting, for example.

[0088] The second guide cylindrical member 79 slidably guides the large shaft portion 76c of the first shaft portion 76 along the axial direction of the first shaft portion 76. The second guide cylindrical member 79 has a cylindrical second guide tube portion 79a and a ring-shaped second annular extension portion 79b that protrudes radially outward from the outer periphery of the axial end portion of the second guide tube portion 79a on the third block cover member 47 side. The inner circumferential surface of the second guide tube portion 79a has an inclined portion 79c that is inclined so that the inner diameter of the second guide tube portion 79a decreases from the third block cover member 47 side toward the fourth block cover member 48 side. As shown in FIG. 7 , with the steering operation input device in the neutral position, the shaft portion end surface 76e of the large shaft portion 76c of the first shaft portion 76 on the fourth block cover member 48 side is located near the second annular extension portion 79b of the second guide tube portion 79a. In addition, the space inside the second guide cylindrical member 79, which is closer to the fourth blocking cover member 48 than the large shaft portion 76c of the first shaft portion 76, serves as a first spring accommodating portion 83 in which a first coil spring 81, which is a biasing member, is accommodated.

[0089] A spring connecting member 80 that connects the first coil spring 81 and the second coil spring 82 is provided at the axial end of the second cylindrical guide member 79 on the side of the fourth blocking cover member 48. The spring connecting member 80 has a cylindrical connecting cylindrical portion 80a and a ring-shaped abutting extension portion 80b that protrudes radially outward from the outer periphery of the axial center of the connecting cylindrical portion 80a. The outer diameter of the abutting extension portion 80b is smaller than the inner diameter of the spring accommodating cylindrical portion 77a of the second shaft portion 77.

[0090] The first coil spring 81 is a coiled linear spring that is provided in a state where no preload is applied, i.e., in a state of free length. The first coil spring 81 is disposed radially outward of the third shaft 49. That is, the first coil spring 81 extends parallel to the third shaft 49 in the first spring accommodating portion 83 of the second guide cylindrical member 79. In the first spring accommodating portion 83, one end of the first coil spring 81 abuts against the shaft end surface 76e of the large shaft portion 76c of the first shaft portion 76, while the other end of the first coil spring 81 abuts against the first abutment surface 80c on the third block cover member 47 side of the spring connecting member 80. Here, the inclined portion 79c also functions as a guide that serves to restrict radially outward displacement of the first coil spring 81 in the event that the first coil spring 81 is displaced radially outward from the axis of the first shaft portion 76 due to external vibration, impact, or the like. The inclined portion 79c can also function as a stopper against which the shaft end surface 76e of the large shaft portion 76c abuts when the first shaft portion 76 moves to the fourth block cover member 48 side to the maximum extent.

[0091] Furthermore, the space within the spring accommodating cylindrical portion 77a of the second shaft portion 77 that is closer to the fourth blocking cover member 48 than the spring connecting member 80 serves as a second spring accommodating portion 84 in which the second coil spring 82 is accommodated.

[0092] The second coil spring 82 is a coiled linear spring provided in a preloaded state. The second coil spring 82 is disposed radially outward from the third shaft 49. That is, the second coil spring 82 extends parallel to the third shaft 49 in a second spring accommodating portion 84 within the spring accommodating cylindrical portion 77a. In this second spring accommodating portion 84, one end of the second coil spring 82 abuts against a second abutment surface 80d on the fourth closing cover member 48 side of the spring connecting member 80, while the other end of the second coil spring 82 abuts against the bottom of the spring accommodating cylindrical portion 77a of the second shaft portion 77 around the protrusion 77d.

[0093] A damper mechanism for damping the biasing force of the first coil spring 81, such as an axle-suspended damper mechanism similar to a suspension provided on a vehicle, may be provided between one end of the first coil spring 81 and the axle end surface 76e of the large axle portion 76c of the first axle portion 76. Similarly, a damper mechanism for damping the biasing force of the second coil spring 82, such as an axle-suspended damper mechanism similar to a suspension provided on a vehicle, may be provided between the other end of the second coil spring 82 and the bottom of the spring housing cylindrical portion 77a of the second axle portion 77. This damper mechanism may also be built into the large axle portion 76c of the first axle portion 76 or the large axle-shaped portion 77b and protrusion 77d of the second axle portion 77.

[0094] 8(a) is an explanatory diagram showing the operation of the steering operation input device when the third shaft 49 is rotated 180 degrees to the left from the neutral position, FIG. 8(b) is an explanatory diagram showing the steering operation input device when the third shaft 49 is rotated 60 degrees to the left from the neutral position, and FIG. 8(c) is an explanatory diagram showing the steering operation input device in the neutral position. In FIG. 8(a) to FIG. 8(c), the position of the shaft end face 76e of the large shaft portion 76c of the first shaft portion 76 in the neutral position is indicated by dashed line A, and the trajectory of the position of the shaft end face 76e of the large shaft portion 76c when the third shaft 49 is rotated 180 degrees to the left from the neutral position is indicated by dashed line B. 8(a) to 8(c), the position of the tip surface 77f of the protrusion 77d of the second shaft portion 77 is indicated by a dashed line C. Note that in Figures 8(a) to 8(c), the position of the tip surface 77f is constant, that is, it is the position of the tip surface 77f in the neutral position.

[0095] First, when the third shaft 49 is rotated leftward by 60 degrees (shown as "-60 degrees" in FIG. 8(b)) from the neutral position shown in FIG. 8(c), the nut 53 moves toward the other end 49b, and accordingly, the first connecting half 72 moves toward the fourth block cover member 48 together with the second connecting half 73, as shown in FIG. 8(b). Then, the third bent piece 72d of the first connecting half 72 presses the first pressing surface 76d of the central shaft portion 76b of the first shaft portion 76 toward the fourth block cover member 48, causing the first shaft portion 76 to move toward the fourth block cover member 48 and compress the first coil spring 81 between the first shaft portion 76 and the spring connecting member 80. At this time, the sixth bent piece 73d of the second connecting half 73 is separated from the second pressing surface 77e of the large shaft portion 77b of the second shaft portion 77. The biasing force of first coil spring 81 generated by compression acts on nut 53 via first shaft portion 76, first connecting half portion 72, and restricting member 55. As a result, a reaction force corresponding to the biasing force of first coil spring 81 acts in a direction that rotates third shaft 49 to the right.

[0096] Furthermore, when the third shaft 49 is rotated leftward from the position shown in FIG. 8(b) to the position of 180 degrees (shown as "-180°" in FIG. 8(a)), the nut 53 moves further toward the other end 49b, and accordingly, the first connecting half 72 moves further toward the fourth block cover member 48 together with the second connecting half 73. Here, the movement of the nut 53 continues until the axial end of the restricting member 55 on the other end 49b side abuts against the second stopper rubber 67. Then, the third bent piece 72d of the first connecting half 72 further presses the first pressing surface 76d of the center shaft portion 76b of the first shaft portion 76 toward the fourth block cover member 48, causing the first shaft portion 76 to move further toward the fourth block cover member 48. As a result, the first shaft portion 76 further compresses the first coil spring 81 between itself and the spring connecting member 80, and in addition, compresses the second coil spring 82 via the first coil spring 81 and the spring connecting member 80. At this time, the sixth bent piece 73d of the second connecting half 73 is further spaced apart from the second pressing surface 77e of the large shaft portion 77b of the second shaft portion 77. Furthermore, the shaft end surface 76e of the first shaft portion 76 abuts against the inclined portion 79c of the second cylindrical guide member 79, thereby restricting movement of the first shaft portion 76 toward the fourth blocking cover member 48. The biasing forces of the first coil spring 81 and the second coil spring 82 generated by the compression further act on the nut 53 via the first shaft portion 76, the first connecting half 72, and the restricting member 55. As a result, a reaction force corresponding to the biasing forces of the first coil spring 81 and the second coil spring 82 acts further in a direction that rotates the third shaft 49 to the right.

[0097] 9(a) and 9(b) are explanatory diagrams showing the operation of the steering operation input device when the third shaft 49 is rotated to the right, with FIG. 9(a) being an explanatory diagram showing the steering operation input device in the neutral position, FIG. 9(b) being an explanatory diagram showing the steering operation input device when the third shaft 49 is rotated 60 degrees to the right from the neutral position, and FIG. 9(c) being an explanatory diagram showing the steering operation input device when the third shaft 49 is rotated 180 degrees to the right from the neutral position. In FIGS. 9(a) and 9(b), the position of the shaft end face 76e of the large shaft portion 76c of the first shaft portion 76 is indicated by a dashed line A. In FIGS. 9(a) and 9(b), the position of the shaft end face 76e is constant, i.e., the position of the shaft end face 76e in the neutral position. In addition, in Figures 9(a) to 9(b), the position of the tip surface 77f of the protrusion 77d in the neutral position is shown by dashed line C, and the trajectory of the position of the tip surface 77f of the protrusion 77d when the third shaft 49 is rotated to the right by 180 degrees from the neutral position is shown by dashed line D.

[0098] First, when the third shaft 49 is rotated to the right by 60 degrees (shown as "+60 degrees" in FIG. 9(b)) from the neutral position shown in FIG. 9(a), the nut 53 moves toward the one end 49a, and accordingly, the second connecting half 73 moves toward the third block cover member 47 together with the first connecting half 72, as shown in FIG. 9(b). Then, the sixth bent piece 73d of the second connecting half 73 presses the second pressing surface 77e of the large shaft portion 77b of the second shaft portion 77 toward the third block cover member 47, causing the second shaft portion 77 to move toward the third block cover member 47 and compress the first coil spring 81 via the second coil spring 82 and the spring connecting member 80. At this time, the third bent piece 72d of the first connecting half 72 is separated from the first pressing surface 76d of the center shaft portion 76b of the first shaft portion 76. Additionally, the bottom of the spring accommodating cylindrical portion 77a of the second shaft portion 77 is spaced apart from the bottom portion 71a of the small cylindrical portion 71 of the generator-side housing portion 58. The biasing force of the first coil spring 81 generated by compression acts on the nut 53 via the second shaft portion 77, the second connecting half portion 73, and the restricting member 55. As a result, a reaction force corresponding to the biasing force of the first coil spring 81 acts in a direction that rotates the third shaft 49 to the left.

[0099] When the third shaft 49 is further rotated to the right from the position shown in FIG. 9(b) to the position of 180 degrees (shown as "+180°" in FIG. 9(c)), the nut 53 moves further toward the one end 49a, and accordingly, the second connecting half 73 moves further toward the third block cover member 47 together with the first connecting half 72. Here, the movement of the nut 53 continues until the axial end of the cap member 56 on the one end 49a side abuts against the first stopper rubber 61. Then, the sixth bent piece 73d of the second connecting half 73 further presses the second pressing surface 77e of the large shaft portion 77b of the second shaft portion 77 toward the third block cover member 47, causing the second shaft portion 77 to move further toward the third block cover member 47. As a result, the second shaft portion 77 further compresses the first coil spring 81 between the large shaft portion 76c of the first shaft portion 76 and the spring connecting member 80, and in addition, compresses the second coil spring 82 relative to the connecting member 80. At this time, the shaft portion end surface 76e of the first shaft portion 76 abuts against the inclined portion 79c of the second guide cylindrical member 79. The biasing forces of the first coil spring 81 and the second coil spring 82 generated by the compression then act on the nut 53 via the second shaft portion 77, the second connecting half 73, and the restricting member 55. As a result, a reaction force corresponding to the biasing forces of the first coil spring 81 and the second coil spring 82 further acts in a direction rotating the third shaft 49 to the left.

[0100] [Effects of the second embodiment] As described above, in the second embodiment, the steering operation input device has the linear motion conversion mechanism 50 that converts rotation of the third shaft 49 into axial movement of the third shaft 49, and the linear motion conversion mechanism 50 is provided with the nut 53 that moves in the axial direction of the third shaft 49. Furthermore, the first coil spring 81 and the second coil spring 82 apply a biasing force to the nut 53 via the connecting portion 43 and the restricting member 55. Therefore, a biasing force is applied to the movement of the nut 53 along the axial direction of the third shaft 49, which allows for a wider range of choices in the type of biasing member.

[0101] In this embodiment, the linear motion conversion mechanism 50 includes a shaft-side ball screw groove 49h, which is a helical groove formed on the outer peripheral surface of the large-diameter cylindrical portion 49e of the third shaft 49, a nut-side ball screw groove 53a, which is a helical groove formed on the inner peripheral surface of the nut 53, which is a linear motion member, a plurality of balls 54 arranged between the ball screw grooves 49h and 53a, a restricting member 55 that restricts rotation of the nut 53 in the rotational direction of the third shaft 49 and allows movement of the nut 53 along the axial direction of the third shaft 49, and a cap member 56 that holds the nut 53 against the restricting member 55. In other words, the linear motion conversion mechanism 50 is a ball screw mechanism. Therefore, the nut 53 moves smoothly on the third shaft 49 by sliding via the plurality of balls 54 arranged between the ball screw grooves 49h and 53a, and therefore the rotation of the third shaft 49 can be quickly and efficiently converted into linear motion.

[0102] Furthermore, in this embodiment, the linear motion conversion mechanism may be a linear motion conversion mechanism using a screw fit instead of a ball screw mechanism. In this case, the linear motion conversion mechanism can be manufactured with fewer parts than a ball screw mechanism, thereby reducing manufacturing costs.

[0103] Furthermore, in this embodiment, the first coil spring 81 and the second coil spring 82 are provided radially outward of the third shaft 49 and extend parallel to the third shaft 49. In other words, the first coil spring 81 and the second coil spring 82 are not provided on the third shaft 49 that includes the linear motion conversion mechanism 50. Therefore, the biasing force applied to the steering operation input device can be easily changed by simply replacing the first coil spring 81 and the second coil spring 82 at a position away from the linear motion conversion mechanism 50.

[0104] In this embodiment, as in the first embodiment, first coil spring 81 may be attached with a preload corresponding to the torque caused by the friction, taking into consideration the friction caused by the sealing member between first coil spring 81 and third shaft 49. Furthermore, the spring constant of first coil spring 81 and the spring constant of second coil spring 82 may be the same or different.

[0105] [Third embodiment] FIG. 10 is a graph showing the operating force versus the operating angle in the third embodiment.

[0106] In the third embodiment, two nonlinear springs are used as biasing members instead of the linear springs of the second embodiment, namely, first coil spring 81 and second coil spring 82. The nonlinear springs may be, for example, barrel-shaped coil springs or drum-shaped coil springs. In the third embodiment, the operating force changes in three stages with respect to the operating angle. More specifically, as shown in FIG. 10 , the operating force increases at a first increasing rate up to a first operating angle α by one nonlinear spring, and then increases at a second increasing rate greater than the first increasing rate from the first operating angle α to a second operating angle β greater than the first operating angle α. Furthermore, the operating force increases at a third increasing rate less than the second increasing rate by the other nonlinear spring from the second operating angle β onward.

[0107] [Effects of the third embodiment] As described above, in the third embodiment, two nonlinear springs are used as biasing members. Therefore, in the third embodiment, too, the operation force is reduced after the second operation angle β, thereby reducing driver fatigue. Furthermore, when operating the dial to cross the second operation angle β, for example, when turning the third shaft 49 from a rightward turn to a leftward turn, the driver is less likely to feel a sense of impediment.

Claims

1. A steering operation input device in which a driver's steering operation is input via a steering operation input member attached to a vehicle, a shaft that receives the steering force from the steering operation input member and rotates around a rotation axis; a biasing member that applies a biasing force against rotation of the shaft, The biasing member is A steering operation input device comprising: a first biasing member that applies a biasing force to the shaft regardless of the rotation direction of the shaft; and a second biasing member that is attached in a preloaded state and that applies a biasing force to the shaft regardless of the rotation direction of the shaft after the first biasing member applies a biasing force.

2. The steering operation input device according to claim 1, The steering operation input device, wherein the first biasing member continues to apply a biasing force to the shaft even after the biasing force of the second biasing member has been applied to the shaft.

3. The steering operation input device according to claim 2, The steering operation input device is characterized in that it has a position switching mechanism that switches the ends of the first biasing member and the second biasing member between an unfixed position and a fixed position when the shaft rotates.

4. The steering operation input device according to claim 3, The steering operation input device, wherein the first biasing member and the second biasing member are torsion springs.

5. The steering operation input device according to claim 4, the shaft includes a first shaft provided with the first biasing member and a second shaft provided with the second biasing member, a connecting member that covers the first shaft and the first biasing member is provided on the radially outer side of the first shaft; the connecting member is connected to the first shaft via the first biasing member and is also connected to the second shaft; The steering operation input device, wherein the second shaft rotates together with the connecting member when the first biasing member reaches a predetermined load.

6. The steering operation input device according to claim 5, The steering operation input device, wherein the predetermined load is a load generated by a preload set in the second biasing member.

7. The steering operation input device according to claim 5, A steering operation input device, wherein an outer diameter of the first shaft is smaller than an inner diameter of the first biasing member when the first biasing member generates a biasing force and is deformed.

8. The steering operation input device according to claim 5, The steering operation input device, wherein the connecting member and the second shaft are fixed to each other via a D-cut portion.

9. The steering operation input device according to claim 5, The steering operation input device, wherein the connecting member and the second shaft are fixed to each other via a spline portion.

10. The steering operation input device according to claim 1, The steering operation input device, wherein the first biasing member and the second biasing member are nonlinear springs.

11. The steering operation input device according to claim 1, the steering operation input device has a housing that accommodates a portion of the shaft and the biasing member, The steering operation input device is characterized in that the housing is provided with a seal member that seals between the housing and an outer peripheral surface of the shaft.

12. The steering operation input device according to claim 1, The steering operation input device has a damper mechanism that applies a damping force to the biasing member.

13. The steering operation input device according to claim 2, the steering operation input device has a linear motion conversion mechanism that converts rotation of the shaft into axial movement of the shaft, the linear motion conversion mechanism includes a linear motion member, The steering operation input device, wherein the first biasing member and the second biasing member apply a biasing force to the linearly moving member.

14. The steering operation input device according to claim 13, The steering operation input device, wherein the first biasing member and the second biasing member are provided radially outward of the shaft and extend parallel to the shaft.

15. The steering operation input device according to claim 13, a steering operation input device characterized in that the linear motion conversion mechanism has a first spiral uneven portion formed on the outer peripheral surface of the shaft and a second uneven portion that engages with the first uneven portion, and has a movable member that can move in the axial direction of the shaft in response to rotational operation of the steering operation input member, and a regulating member that regulates the rotation of the movable member in the rotational direction of the shaft and allows movement of the movable member along the axial direction of the shaft.

16. The steering operation input device according to claim 13, The steering operation input device is characterized in that the linear motion conversion mechanism is a ball screw mechanism.

17. A steer-by-wire type steering system comprising the steering operation input device according to any one of claims 1 to 16.

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