Vehicle steering device
By designing annular elastic components with different gaps in the steering device for vehicles, the problem of insufficient load absorption characteristics in the prior art is solved, and a more refined load absorption and better load relief effect is achieved.
Patent Information
- Application Number
- CN202080101296.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2020-06-16
- Publication Date
- 2024-12-13
- Estimated Expiration
- 2040-06-16
AI Technical Summary
The elastomer of the existing vehicle steering device has two stages of load absorption characteristics, making it difficult to meet the more refined load absorption requirements.
By setting a gap between the shell and the elastic body, designing the first and second elastic parts in the annular shape, the sizes of the first and second voids affect the load characteristics of different compression ranges, respectively, providing more refined load absorption characteristics. .
A more refined load absorption characteristic is achieved, and the handling sense and load relief effect of the steering device are improved.
Smart Images
Figure CN115884913B_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a vehicle steering device including a stopper provided at a shaft end of a steering shaft (for example, a rack shaft) and an elastic body for relieving collision of the stopper. Background Art
[0002] Among the commonly used vehicle steering devices, there is a so-called rack-and-pinion steering device that converts the rotational motion from the steering wheel into the axial motion of the rack shaft (steering shaft) through a rack and pinion. The rack shaft is housed in a housing so as to be movable in the vehicle width direction. A stopper (rack end) is provided at the axial end of the rack shaft. The stopper gently abuts against an elastic body (buffer component) provided at the end of the housing, thereby limiting the movement of the rack shaft and the stopper. This type of vehicle steering device is known, for example, from Patent Document 1.
[0003] The elastic body (buffer component) of the vehicle steering device known from Patent Document 1 is composed of a low spring rate portion and a high spring rate portion, and is integrally molded by one elastic material. The low spring rate portion and the high spring rate portion are both annular structures centered on the rack shaft and arranged in the vehicle width direction. The low spring rate portion protrudes from the end surface of the high spring rate portion toward the stopper. The radial width of the low spring rate portion is smaller than the radial width of the high spring rate portion. The pressure-bearing area of the low spring rate portion is smaller than the pressure-bearing area of the high spring rate portion. Therefore, the spring ratio of the low spring rate portion is smaller than the spring ratio of the high spring rate portion. The low spring rate portion is compressed and deformed preferentially than the high spring rate portion. When the elastic body is subjected to a smaller impact load based on normal operation, the low spring rate portion is deformed to absorb the load. When the elastic body is subjected to a larger impact load, the low spring rate portion and the high spring rate portion are deformed to absorb the load. Therefore, the load on the steering device can be mitigated.
[0004] Prior art literature
[0005] Patent Literature
[0006] Patent Document 1: Japanese Patent No. 6209114 Summary of the invention
[0007] Problems to be solved by the invention
[0008] The elastic body known from Patent Document 1 has a structure in which a low spring rate portion and a high spring rate portion are arranged in a row in the vehicle width direction. Therefore, the characteristics of the compression deformation amount of the elastic body with respect to the compression load applied from the stopper to the elastic body, that is, the load absorption characteristics, are two-stage characteristics. In recent years, it has been required to further improve the steering feel of a vehicle steering device. For this reason, the elastic body preferably has a finer load absorption characteristic.
[0009] An object of the present invention is to provide a vehicle steering device including an elastic body having a more refined load absorbing property.
[0010] Means for solving problems
[0011] The present inventors have conducted intensive studies and have found that an elastic body having finer load absorbing characteristics can be provided by appropriately setting a gap between the housing and the elastic body. The present invention has been completed based on this finding.
[0012] Hereinafter, the present disclosure will be described.
[0013] According to the present disclosure, there is provided a vehicle steering device having:
[0014] A steering axis that can move in the vehicle width direction;
[0015] a stopper, which is arranged at the end of the steering shaft;
[0016] a housing extending in the vehicle width direction and capable of accommodating the steering shaft, wherein an opening portion of an end portion of the housing in the vehicle width direction is formed by an outer cylindrical portion on a radially outer side, an inner cylindrical portion on a radially inner side, and an annular and flat bottom surface closing one end of the outer cylindrical portion and one end of the inner cylindrical portion, so as to be annular and open toward the stopper and have a U-shaped cross section, wherein a length from the bottom surface to an open end of the inner cylindrical portion is shorter than a length from the bottom surface to an open end of the outer cylindrical portion; and
[0017] An elastic body, which is composed of an annular elastic one-piece molded part, in which the steering shaft is inserted in a manner that allows it to move in the vehicle width direction, and the one-piece molded part is composed of the following parts: an annular first elastic part, which has a length equal to the length from the bottom surface to the open end of the inner tube part, is embedded in the opening part, and is supported by the inner circumference of the outer tube part and the bottom surface over the entire surface, and has a first gap throughout the entire circumference between the first elastic part and the outer circumference of the inner tube part; and an annular second elastic part, which extends from the first elastic part toward the stopper, and has a second gap larger than the first gap throughout the entire circumference between the second elastic part and the inner circumference of the outer tube part.
[0018] Effects of the Invention
[0019] The present invention can provide a vehicle steering device including an elastic body having a more refined load absorbing property. BRIEF DESCRIPTION OF THE DRAWINGS
[0020] Figure 1 It is a schematic diagram of the vehicle steering device of Example 1.
[0021] Figure 2 yes Figure 1 A cross-sectional view of the mitigation device shown.
[0022] Figure 3 This is a cross-sectional view of an elastic body provided in an opening portion of a housing of the vehicle steering device of Example 1.
[0023] Figure 4 yes Figure 3 An exploded view of the opening of the housing and the elastomer is shown.
[0024] Figure 5 yes Figure 3 The diagram shows the effect of the initial compression of the elastic body.
[0025] Figure 6 yes Figure 5 The diagram shows the mid-term effect of compression of the elastomer.
[0026] Figure 7 yes Figure 6 The diagram shows the effect of the elastomer in the later stage of compression.
[0027] Figure 8 Yes means Figure 3 The characteristic diagram of the elastic body's compression amount relative to the compressive load is shown.
[0028] Fig. 9 This is a cross-sectional view of an elastic body provided in an opening portion of a housing of a vehicle steering device according to a second embodiment.
[0029] Fig.10 This is a cross-sectional view of an elastic body provided in an opening portion of a housing of a vehicle steering device according to a third embodiment.
[0030] Fig.11 This is a cross-sectional view of an elastic body provided in an opening portion of a housing of a vehicle steering device according to a fourth embodiment.
[0031] Fig.12 yes Fig.11 An exploded view of the opening of the housing and the elastomer is shown.
[0032] Fig.13 yes Fig.11 The diagram shows the effect of the initial compression of the elastic body.
[0033] Fig.14 yes Fig.13 The diagram shows the mid-term effect of compression of the elastomer.
[0034] Fig.15 yes Fig.14 The diagram shows the effect of the elastomer in the later stage of compression. DETAILED DESCRIPTION
[0035] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. In addition, the mode shown in the accompanying drawings is an example of the present invention, and the present invention is not limited to this mode. In the description, left and right refer to left and right based on the occupants riding in the vehicle, and front and back refer to front and back based on the direction of travel of the vehicle.
[0036] <Example 1>
[0037] Reference Figures 1 to 8 The vehicle steering device 10 according to the first embodiment will be described.
[0038] like Figure 1 As shown, the vehicle steering device 10 is constructed to include: a steering system 20 from a steering wheel 21 of the vehicle to wheels 29, 29 (steering wheels 29, 29), an auxiliary torque mechanism 40 for adding auxiliary torque to the steering system 20, and left and right (on both sides of the vehicle width direction) relief devices 50, 50.
[0039] The steering system 20 is constructed by comprising: a steering wheel 21; a steering shaft 22 connected to the steering wheel 21; an input shaft 24 connected to the steering shaft 22 via a universal joint 23; a steering shaft 26 connected to the input shaft 24 via a first transmission mechanism 25; and left and right wheels 29, 29 (on both sides in the vehicle width direction) connected to both ends of the steering shaft 26 via ball joints 27, 27, steering tie rods 28A, 28A and steering knuckles 28B, 28B.
[0040] The first transmission mechanism 25 is constituted by a rack and pinion mechanism, for example. The steering shaft 26 is movable in the through hole 31 of the housing 30 in the vehicle width direction. Both ends of the steering shaft 26 protrude from both ends of the housing 30 in the vehicle width direction. Ball joints 27, 27 are provided at both ends of the steering shaft 26 in the longitudinal direction.
[0041] The housing 30 extends in the vehicle width direction to accommodate the steering shaft 26 and has a through hole 31 extending in the vehicle width direction and openings 32, 32 at both ends in the vehicle width direction. The openings 32, 32 are bottomed circular holes that are concentric with the through hole 31 and have a larger diameter than the through hole 31.
[0042] According to the steering system 20 , when the driver steers the steering wheel 21 , the left and right wheels 29 , 29 can be steered by using the steering torque via the first transmission mechanism 25 , the steering shaft 26 , and the left and right tie rods 28A, 28A.
[0043] The auxiliary torque mechanism 40 is composed of a steering torque sensor 41, a control unit 42, an electric motor 43, and a second transmission mechanism 44. The steering torque sensor 41 detects the steering torque applied to the steering wheel 21 of the steering system 20. The control unit 42 generates a control signal based on the torque detection signal of the steering torque sensor 41. The electric motor 43 generates a motor torque (auxiliary torque) corresponding to the steering torque based on the control signal of the control unit 42. The second transmission mechanism 44 transmits the auxiliary torque generated by the electric motor 43 to the steering shaft 26, and the second transmission mechanism 44 is composed of, for example, a belt transmission mechanism 45 and a ball screw 46.
[0044] According to the vehicle steering system 10 , the wheels 29 , 29 can be steered via the steering shaft 26 using a composite torque obtained by adding the assist torque of the electric motor 43 to the steering torque of the driver.
[0045] As described above, the vehicle steering system 10 includes the left and right (both sides in the vehicle width direction) buffering devices 50, 50. The left and right buffering devices 50, 50 can buffer the collision load generated when the steering shaft 26 moves to the end of the stroke. Hereinafter, the buffering device 50 on the left side will be described as a representative.
[0046] like Figure 2 As shown, the relief device 50 includes a stopper 51 and an elastic body 52 .
[0047] The stopper 51 is provided at the shaft end 26a (end 26a) of the steering shaft 26 exposed from the housing 30, and is constituted by, for example, a bracket 27a (also referred to as a joint housing 27a) of the ball joint 27. The bracket 27a can move forward and backward relative to the opening 32 of the housing 30. The end surface 51a of the stopper 51 is a flat surface at a right angle to the steering shaft 26, and faces the opening 32 of the housing 30.
[0048] like Figure 2 and Figure 3 As shown, the opening portion 32 at the end of the shell 30 in the vehicle width direction is formed by an outer cylinder portion 33 (first cylinder portion 33) on the radially outer side, an inner cylinder portion 34 (second cylinder portion 34) on the radially inner side, and an annular bottom surface 35 (bottom surface 35 of the opening portion 32) that closes one end of the outer cylinder portion 33 and one end of the inner cylinder portion 34, forming a ring shape that opens toward the stopper 51 and has a U-shaped cross section.
[0049] The shapes of the inner circumferential surface 33a of the outer cylinder portion 33 and the outer circumferential surface 34a of the inner cylinder portion 34 are true circles that are concentric with each other. The outer circumferential surface 34a of the inner cylinder portion 34 is a tapered surface that becomes thinner from the bottom surface 35 toward the open end 34b of the inner cylinder portion 34. Hereinafter, the outer circumferential surface 34a of the inner cylinder portion 34 is sometimes referred to as "the tapered surface 34a of the inner cylinder portion 34". The angle θ (taper angle θ) of the tapered surface 34a of the inner cylinder portion 34 is arbitrarily set. The bottom surface 35 is a flat surface that is perpendicular to the steering shaft 26 and faces the end surface 51a of the stopper 51. The length L1 from the bottom surface 35 to the open end 34b of the inner cylinder portion 34 (the open end surface 34b) is shorter than the length L2 from the bottom surface 35 to the open end 33b of the outer cylinder portion 33 (the open end surface 33b).
[0050] like Figure 3 and Figure 4 As shown, the shape of the angle (corner) between the inner peripheral surface 33a of the outer cylinder portion 33 and the bottom surface 35 is an arc shape. The shape of the angle (corner) between the outer peripheral surface 34a of the inner cylinder portion 34 and the bottom surface 35 is an arc shape. The shape of the angle (corner) between the outer peripheral surface 34a of the inner cylinder portion 34 and the open end 34b of the inner cylinder portion 34 is an arc shape.
[0051] The elastic body 52 is provided in the opening 32 of the housing 30 and is an annular member into which the steering shaft 26 is inserted so as to be movable in the vehicle width direction. The elastic body 52 is composed of an elastic integrally molded part, and the integrally molded part is composed of an annular first elastic part 60 and an annular second elastic part 70. The elastic body 52 is composed of an elastic material such as polyurethane resin, rubber, etc.
[0052] The first elastic portion 60 has a length L1 equal to the length L1 from the bottom surface 35 of the opening portion 32 to the open end 34b of the inner tube portion 34, and is fitted into the opening portion 32. The entire surface of the outer peripheral surface 61 of the first elastic portion 60 is supported by the inner peripheral surface 33a of the outer tube portion 33. With respect to the diameter D1 of the inner peripheral surface 33a of the outer tube portion 33, the diameter d1 of the outer peripheral surface 61 of the first elastic portion 60 is set to be the same as the diameter D1 or slightly larger than the diameter D1. The entire surface of the bottom surface 62 of the first elastic portion 60 is supported by the bottom surface 35 of the opening portion 32.
[0053] A first gap 81 is provided over the entire circumference between the outer circumferential surface 34a of the inner tube portion 34 and the inner circumferential surface 63 of the first elastic portion 60. The size δ1 of the first gap 81 is set in consideration of the elastic deformation of the entire elastic body 52 when a compressive load acts on the elastic body 52 from the stopper 51. The size δ1 of the first gap 81 is preferably constant (uniform).
[0054] The inner circumferential surface 63 of the first elastic portion 60 is a tapered surface along the outer circumferential surface 34a of the inner tube portion 34. That is, the inner circumferential surface 63 of the first elastic portion 60 is a tapered surface that tapers from the bottom surface 62 of the first elastic portion 60 toward the tip 64. Hereinafter, the inner circumferential surface 63 of the first elastic portion 60 is sometimes referred to as "the tapered surface 63 of the first elastic portion 60". The straight line Lx extending along the tapered surface 63 of the first elastic portion 60 is referred to as "the extension line Lx of the tapered surface 63". The corner (corner) between the outer circumferential surface 61 and the bottom surface 62, and the corner (corner) between the bottom surface 62 and the inner circumferential surface 63 of the first elastic portion 60 are chamfered.
[0055] The second elastic portion 70 extends continuously from the terminal end 64 of the first elastic portion 60 toward the stopper 51. A second gap 82 is provided over the entire circumference between the outer peripheral surface 71 of the second elastic portion 70 and the inner peripheral surface 33a of the outer tube portion 33. The size δ2 of the second gap 82 is set in consideration of the elastic deformation amount of the entire elastic body 52 when the compressive load acts on the elastic body 52 from the stopper 51, and the size δ2 of the second gap 82 is larger than the size δ1 of the first gap 81.
[0056] More specifically, the diameter d2 of the end 71a of the outer peripheral surface 71 of the second elastic portion 70 is smaller than the diameter d1 of the outer peripheral surface 61 of the first elastic portion 60. The outer peripheral surface 71 is a tapered surface that tapers from the end 61a of the outer peripheral surface 61 of the first elastic portion 60 toward the end 71a of the outer peripheral surface 71 of the second elastic portion 70. Furthermore, the contour of the outer peripheral surface 71 is curved as a whole from the base end 71b (the end 64 of the first elastic portion 60) to the end 71a.
[0057] The outer peripheral surface 71 of the second elastic portion 70 preferably has Figure 4 The annular first groove 72 is indicated by an imaginary line in FIG. The first groove 72 is recessed in a curved shape from the end 61a of the outer peripheral surface 61 of the first elastic portion 60 toward the end surface 73 of the second elastic portion 70 over the entire circumference.
[0058] The inner circumferential surface 74 of the second elastic portion 70 is a tapered surface along the extension line Lx of the tapered surface 63 of the first elastic portion 60 (the outer circumferential surface 34a of the inner tube portion 34). The end 74a of the inner circumferential surface 74 of the second elastic portion 70 preferably coincides with the intersection point Px of the end surface 73 of the second elastic portion 70 and the extension line Lx. The diameter d4 of the intersection point Px (the end 74a of the inner circumferential surface 74) is larger than the diameter D2 of the inner circumferential surface 34c of the inner tube portion 34. The length of the second elastic portion 70 is L3.
[0059] The inner circumferential surface 74 of the second elastic part 70 has an annular second groove 75 that is recessed over the entire circumference. The second groove 75 is recessed in a curved shape over the entire circumference from the distal end 63a of the inner circumferential surface 63 of the first elastic part 60 toward the distal end surface 73 of the second elastic part 70 .
[0060] The boundary 76 between the inner peripheral surface 63 of the first elastic portion 60 and the inner peripheral surface 74 of the second elastic portion 70 is an arc-shaped surface extending over the entire circumference.
[0061] It is preferred that a ring-shaped and flat plate 90 (collar 90) is provided at least at a portion of the end surface 73 of the second elastic portion 70 that contacts the stopper 51. The flat plate 90 is made of metal. The flat plate 90 is integrated with the second elastic portion 70 by, for example, integral molding, welding, or bonding. The outer peripheral surface 91 of the flat plate 90 is exposed from the second elastic portion 70. The outer diameter d5 of the flat plate 90 is the same as the diameter d2 of the end 71a of the outer peripheral surface 71 of the second elastic portion 70. The hole diameter d6 of the flat plate 90 is smaller than the diameter d4 of the end 74a (intersection point Px) of the inner peripheral surface 74 of the second elastic portion 70, and is the same as the diameter D2 of the inner peripheral surface 34c of the inner cylinder portion 34. The plate thickness of the flat plate 90 is Tp.
[0062] Stopper 51 (see Figure 3 ) collides with the end face 73 of the second elastic part 70 via the flat plate 90. The flat plate 90 can be used to evenly distribute the compressive load applied to the second elastic part 70 from the stopper 51 to the end face 73 of the second elastic part 70. Moreover, the end face 73 of the second elastic part 70 is covered by the flat plate 90, thereby being protected from the outside.
[0063] Next, refer to Figure 3 , Figures 5 to 8 The characteristics of the elastic body 52 will be described.
[0064] Now, if Figure 3 As shown by the imaginary line in the middle, the stopper 51 is located away from the elastic body 52. At this time, the end surface 51a of the stopper 51 presses the end surface 73 of the second elastic part 70 via the flat plate 90, and thus, the pressing force fc, that is, the value of the compression load fc is 0 (fc = 0). The value of the compression amount St of the elastic body 52 is 0 (St = 0).
[0065] Then, the end surface 51a of the stopper 51 presses the distal end surface 73 of the second elastic portion 70 via the flat plate 90, whereby a compressive load fc acts on the distal end surface 73 of the second elastic portion 70 from the distal end surface 73 of the stopper 51. The elastic body 52 receives the compressive load fc and starts to compress.
[0066] The entire outer circumferential surface 61 and the bottom surface 62 of the first elastic portion 60 are supported by the inner circumferential surface 33a of the outer cylinder portion 33 and the bottom surface 35 of the opening portion 32. On the other hand, a first gap 81 is provided on the radially inner side of the inner circumferential surface 63 of the first elastic portion 60. A second gap 82 is provided on the radially outer side of the outer circumferential surface 71 of the second elastic portion 70. Therefore, the elastic body 52 begins to be compressed and deformed as a whole, and the inner circumferential surface 63 of the first elastic portion 60 begins to elastically deform radially inward, and the outer circumferential surface 71 of the second elastic portion 70 begins to elastically deform radially outward. Accompanying this, the compression amount St of the elastic body 52 with respect to the compressive load fc gradually increases.
[0067] As the compressive load fc increases, the first gap 81 and the second gap 82 decrease. The size δ1 of the first gap 81 is smaller than the size δ2 of the second gap 82. Therefore, the elastic body 52 continues to be compressed and deformed as a whole, and the inner peripheral surface 63 of the first elastic part 60 is in contact with the outer peripheral surface 34a of the inner tube part 34 and supported (see Figure 5 ). The value of the compressive load fc at this time is fc1, and the value of the compression amount St of the elastic body 52 is St1. The compression range A1 in which the value of the compression amount St of the elastic body 52 is from 0 to fc1 is referred to as the "first compression range A1".
[0068] In the first compression range A1, the elastic body 52 exhibits a first load characteristic (low spring rate characteristic) in which the ratio of the compression load fc per unit amount of the compression amount St of the axial deformation of the steering shaft 26 gradually increases. That is, in the first compression range A1, the elastic body 52 has a tendency to be easily elastically deformed due to the first gap 81 and the second gap 82. The first load characteristic, that is, the size of the first compression range A1 is determined in particular by the size δ1 of the first gap 81.
[0069] As the compressive load fc increases, the second gap 82 decreases. Therefore, the elastic body 52 continues to be compressed and deformed as a whole, and the outer peripheral surface 71 of the second elastic portion 70 is in contact with the inner peripheral surface 33a of the outer tube portion 33 and supported (see Figure 6 ). The value of the compressive load fc at this time is fc2, and the value of the compression amount St of the elastic body 52 is St2. The compression range A2 in which the value of the compression amount St of the elastic body 52 is from fc1 to fc2 is referred to as the "second compression range A2".
[0070] In the second compression range A2, the elastic body 52 has a tendency to exhibit a second load characteristic (medium spring rate characteristic) in which the ratio of the compression load fc per unit amount of the compression amount St of the axial deformation of the steering shaft 26 is larger than the first load characteristic. The second load characteristic, that is, the size of the second compression range A2 is determined in particular by the size δ2 of the second gap 82.
[0071] As the compressive load fc further increases, the inner peripheral surface 74 of the second elastic portion 70 bulges radially inward, and a portion of the second elastic portion 70 bulges from the second gap 82 toward the stopper 51 (see Figure 7 ). That is, the compression deformation of the elastic body 52 reaches the limit. The value of the compression load fc at this time is fc3, and the value of the compression amount St of the elastic body 52 is St3. The compression range A3 in which the value of the compression amount St of the elastic body 52 is from fc2 to fc3 is called the "third compression range A3".
[0072] In the third compression range A3, the elastic body 52 tends to exhibit a third load characteristic (high spring rate characteristic) in which the ratio of the compression load fc per unit amount of the compression amount St of the axial deformation of the steering shaft 26 is sharply increased compared with the second load characteristic.
[0073] The characteristics of the compressive load fc and the compression amount St described above are summarized in Figure 8 . Figure 8 This is a characteristic diagram showing the characteristics of the compression amount St with respect to the compression load fc, with the vertical axis being the compression load fc input to the elastic body 52 and the horizontal axis being the compression amount St of the elastic body 52. The characteristic curve shown in this characteristic diagram shows the following.
[0074] In the first compression range A1, the elastic body 52 is easily deformed due to the influence of the first gap 81 and the second gap 82. In the second compression range A2, the elastic body 52 is not affected by the first gap 81, but only affected by the second gap 82, so it is difficult for the elastic body 52 to deform compared with the first compression range A1. In the third compression range A3, the elastic body 52 is not affected by the first gap 81 and the second gap 82, so it is difficult for the elastic body 52 to deform sharply compared with the second compression range A2. In this way, by appropriately setting the size δ1 of the first gap 81 and the size δ2 of the second gap 82, each compression range A1 to A3 can be set to the best.
[0075] Next, refer to Figure 3 , Figures 5 to 8 , while explaining the function of the mitigation device 50.
[0076] Now, if Figure 3 As shown by the imaginary line in FIG. 1 , the stopper 51 is located away from the elastic body 52. Figure 1) and / or the so-called normal operation based on the drive of the electric motor 43, the steering shaft 26 moves toward the center of the vehicle width. When the steering shaft 26 moves to the limit of movement (end of stroke) toward the center of the vehicle width, the end face 51a of the stopper 51 slowly collides with the end face 73 of the second elastic portion 70 via the flat plate 90. At this time, the impact load based on the normal operation is input from the end face 51a of the stopper 51 to the end face 73 of the second elastic portion 70. As a result, the elastic body 52 absorbs the impact load (compression load) based on the normal operation by elastic deformation. Thereafter, if the steering shaft 26 moves toward the outer side of the vehicle width, the end face 51a of the stopper 51 separates from the flat plate 90. As a result, the elastic body 52 returns to its original position by its own elasticity.
[0077] In addition, if Figure 3 As shown by the imaginary line in FIG. 2 , when the stopper 51 leaves the elastic body 52, for example, when the wheel 31 (refer to FIG. 2 ) Figure 1 ) when climbing onto a curbstone of a road, a large axial impact load will be applied to the stopper 51 from the wheel 31. As a result, the end face 51a of the stopper 51 collides with the end face 73 of the second elastic part 70 via the flat plate 90. The impact load at this time is larger than the impact load based on normal operation. The impact load is input from the end face 51a of the stopper 51 to the end face 73 of the second elastic part 70. At this time, if Figure 5 to Figure 7 As shown, the elastic body 52 is greatly deformed to absorb the impact load. As a result, the impact load received by the steering device 10 can be reduced.
[0078] The above descriptions are summarized as follows.
[0079] like Figure 1 to Figure 4 As shown, the vehicle steering device 10 has:
[0080] A steering shaft 26, which can move in the vehicle width direction;
[0081] a stopper 51 disposed at the end 26a of the steering shaft 26;
[0082] a housing 30 extending in the vehicle width direction and capable of accommodating the steering shaft 26, wherein an opening portion 32 at an end portion of the housing 30 in the vehicle width direction is formed by an outer cylindrical portion 33 on the radially outer side, an inner cylindrical portion 34 on the radially inner side, and an annular and flat bottom surface 35 closing one end of the outer cylindrical portion 33 and one end of the inner cylindrical portion 34, so as to be an annular shape opening toward the stopper 51 and having a U-shaped cross section, and a length L1 from the bottom surface 35 to an open end 34b of the inner cylindrical portion 34 is shorter than a length L2 from the bottom surface 35 to an open end 33b of the outer cylindrical portion 33; and
[0083] The elastic body 52 is composed of an annular elastic one-piece molded part, into which the steering shaft 26 is inserted so as to be movable in the vehicle width direction. The one-piece molded part is composed of the following parts: an annular first elastic portion 60, which has a length L1 equal to the length L1 from the bottom surface 35 to the open end 34b of the inner tube portion 34, is fitted in the opening portion 32, and is supported entirely by the inner peripheral surface 33a of the outer tube portion 33 and the bottom surface 35, and has a first gap 81 throughout the entire circumference between the first elastic portion 60 and the outer peripheral surface 34a of the inner tube portion 34; and an annular second elastic portion 70, which extends from the first elastic portion 60 toward the stopper 51, and has a second gap 82 larger than the first gap 81 throughout the entire circumference between the second elastic portion 70 and the inner peripheral surface 33a of the outer tube portion 33.
[0084] In this way, the first elastic portion 60 is restricted from elastic deformation by the inner peripheral surface 33a of the outer cylinder portion 33 and the bottom surface 35 of the opening portion 32, and a first gap 81 is provided between the first elastic portion 60 and the outer peripheral surface 34a of the inner cylinder portion 34, thereby allowing the first elastic portion 60 to elastically deform radially inward to a certain extent. The second elastic portion 70 has a second gap 82 between the inner peripheral surface 33a of the outer cylinder portion 33, thereby allowing the second elastic portion 70 to elastically deform radially outward to a certain extent. Therefore, by appropriately setting the size δ1 of the first gap 81 and the size δ2 of the second gap 82, the load characteristics (spring rate characteristics) of the elastic body 52 can be optimized. Therefore, it is possible to provide a vehicle steering device 10 having an elastic body 52 with a more refined load absorption characteristic.
[0085] And, if Figure 3 and Figure 4 As shown, the outer peripheral surface 71 of the second elastic part 70 has an annular first groove 72 that is recessed over the entire circumference. Therefore, the second elastic part 70 is more easily elastically deformed.
[0086] And, if Figure 3 and Figure 4 As shown, the outer peripheral surface 34a of the inner tube portion 34 is a tapered surface 34a that tapers from the bottom surface 35 toward the open end 34b of the inner tube portion 34.
[0087] A size δ1 of the first gap 81 between the outer circumferential surface 34 a of the inner tube portion 34 and the inner circumferential surface 63 of the first elastic portion 60 is constant.
[0088] Therefore, it is possible to alleviate the load acting from the inner peripheral surface 63 of the first elastic portion 60 to the outer peripheral surface 34 a of the inner tube portion 34 .
[0089] And, if Figure 3 and Figure 4 As shown, the inner circumferential surface 74 of the second elastic part 70 is a tapered surface along the extension line Lx of the tapered surface 63 of the first elastic part 60 and has an annular second groove 82 that is recessed over the entire circumference. Therefore, the second elastic part 70 is more easily elastically deformed.
[0090] And, if Figure 3 and Figure 4 As shown, an annular flat plate 90 is provided at least at a portion of the end surface 73 of the second elastic portion 70 that contacts the stopper 51. Therefore, the compressive load can be uniformly input to the end surface 73 of the second elastic portion 70. The elastic body 52 can efficiently absorb the compressive load.
[0091] In other words, Figure 1 to Figure 3 As shown, the vehicle steering device 10 has:
[0092] A steering shaft 26, which can move in the vehicle width direction;
[0093] a stopper 51 disposed at the end 26a of the steering shaft 26;
[0094] a housing 30 extending in the vehicle width direction and capable of accommodating the steering shaft 26, wherein an opening portion 32 at an end portion of the housing 30 in the vehicle width direction is formed by an outer cylindrical portion 33 on the radially outer side, an inner cylindrical portion 34 on the radially inner side, and an annular and flat bottom surface 35 closing one end of the outer cylindrical portion 33 and one end of the inner cylindrical portion 34, so as to be an annular shape opening toward the stopper 51 and having a U-shaped cross section, and a length L1 from the bottom surface 35 to an open end 34b of the inner cylindrical portion 34 is shorter than a length L2 from the bottom surface 35 to an open end 33b of the outer cylindrical portion 33; and
[0095] The elastic body 52 is composed of an annular elastic integral molded part, through which the steering shaft 26 is inserted so as to be movable in the vehicle width direction, and the integral molded part is composed of the following parts: an annular first elastic portion 60 having a length L1 equal to a length L1 from the bottom surface 35 to the open end 34b of the inner tube portion 34, fitted in the opening portion 32, and supported entirely by the inner peripheral surface 33a of the outer tube portion 33 and the bottom surface 35, and having a first gap 81 throughout the entire circumference between the first elastic portion and the outer peripheral surface 34a of the inner tube portion 34; and an annular second elastic portion 70 extending from the first elastic portion 60 toward the stopper 51, and having a second gap 82 larger than the first gap 81 throughout the entire circumference between the second elastic portion 70 and the inner peripheral surface 33a of the outer tube portion 33,
[0096] The outer peripheral surface 71 of the second elastic part 70 has an annular first groove 72. The first groove 72 is curvedly recessed from the end 61a of the outer peripheral surface 61 of the first elastic part 60 toward the end surface 73 of the second elastic part 70 over the entire circumference.
[0097] The outer peripheral surface 34a of the inner cylinder portion 34 is a tapered surface that tapers from the bottom surface 35 toward the open end 34b of the inner cylinder portion 34, and the edge between the outer peripheral surface 34a of the inner cylinder portion 34 and the open end 34b of the inner cylinder portion 34 is an arc-shaped surface.
[0098] The size δ1 of the first gap 81 between the outer circumferential surface 34a of the inner tube portion 34 and the inner circumferential surface 63 of the first elastic portion 60 is fixed.
[0099] The inner circumferential surface 74 of the second elastic portion 70 is a tapered surface along the extension line Lx of the tapered surface 63 of the first elastic portion 60 and has an annular second groove 82 that is recessed over the entire circumference.
[0100] The boundary 76 between the inner circumferential surface 63 of the first elastic portion 60 and the inner circumferential surface 74 of the second elastic portion 70 is an arc-shaped surface extending over the entire circumference.
[0101] An annular flat plate 90 is provided at least at a portion of the distal end surface 73 of the second elastic portion 70 that contacts the stopper 51 .
[0102] Next, refer to Fig. 9 Next, a vehicle steering system 10A according to the second embodiment will be described.
[0103] <Example 2>
[0104] Fig. 9 The cross-sectional structure of the elastic body 52A provided in the opening portion 32 of the housing 30 of the vehicle steering device 10A of the second embodiment is similar to the above-mentioned Figure 3 Represented accordingly.
[0105] Fig. 9 The vehicle steering device 10A shown in the figure is characterized in that the following two structures are changed, and the other basic structures are the same as those described above. Figure 1 to Figure 7 The same parts as those of the vehicle steering device 10 are denoted by the same reference numerals and detailed description thereof is omitted.
[0106] The first change is to Figure 3 The outer peripheral surface 34a of the inner cylinder portion 34 of the first embodiment shown is changed to Fig. 9The outer peripheral surface 34Aa of the inner cylindrical portion 34A shown in the figure. The outer peripheral surface 34Aa of the second embodiment is not a tapered surface but a straight surface parallel to the inner peripheral surface 33a of the outer cylindrical portion 33.
[0107] The second change is to Figure 3 The elastic body 52 of the first embodiment shown is changed to an elastic body 52A. In the elastic body 52A of the second embodiment, the inner peripheral surface 63A of the first elastic portion 60 is a straight surface parallel to the outer peripheral surface 34Aa of the inner cylinder portion 34A. Between the outer peripheral surface 34Aa of the inner cylinder portion 34A and the inner peripheral surface 63A of the first elastic portion 60, there is a first gap 81 of size δ1 as in the first embodiment. The inner peripheral surface 74A of the second elastic portion 70 of the second embodiment is a straight surface along the inner peripheral surface 63A of the first elastic portion 60, and does not have the second groove 75 of the first embodiment (see Figure 3 ).
[0108] Next, refer to Fig.10 Next, a vehicle steering system 10B according to the third embodiment will be described.
[0109] <Example 3>
[0110] Fig.10 The cross-sectional structure of the elastic body 52B provided in the opening 32 of the housing 30 of the vehicle steering device 10B of the third embodiment is similar to the above-mentioned Figure 3 Represented accordingly.
[0111] Fig.10 The vehicle steering device 10B shown in the figure is characterized in that the above Figure 3 The elastic body 52 of the embodiment 1 shown in the figure is changed to the elastic body 52B, and the other basic structures are the same as those described above. Figure 1 to Figure 7 The same parts as those of the vehicle steering device 10 are represented by the same reference numerals and detailed description thereof is omitted.
[0112] The elastic body 52B of the third embodiment does not have the first groove 72 of the first embodiment described above on the outer peripheral surface 71 of the second elastic portion 70 (see Figure 3 ). In addition, in the elastic body 52B of the third embodiment, the inner peripheral surface 74B of the second elastic portion 70 is a straight surface parallel to the outer peripheral surface 71 of the second elastic portion 70, and does not have the second groove 75 of the first embodiment (see Figure 3 ).
[0113] Next, refer to Figure 11 to Figure 15 Next, a vehicle steering system 10C according to a fourth embodiment will be described.
[0114] <Example 4>
[0115] Fig.11The cross-sectional structure of the elastic body 52C provided in the opening portion 32 of the housing 30 of the vehicle steering device 10C of the fourth embodiment is similar to the above-mentioned Figure 3 Represented accordingly. Fig.12 express Fig.11 The decomposed structure of the opening portion 32 of the housing 30 and the elastic body 52C shown in FIG. Figure 4 Represented accordingly.
[0116] Fig.11 as well as Fig.12 The vehicle steering system 10C shown in the figure is characterized in that the above Figure 3-4 The elastic body 52 of the embodiment 1 shown in the figure is changed to an elastic body 52C, and the other basic structures are the same as those described above. Figure 1 to Figure 7 The same parts as those of the vehicle steering device 10 are represented by the same reference numerals and detailed description thereof is omitted.
[0117] Regarding the elastic body 52C of the fourth embodiment, the second elastic portion 70 has an annular extension portion 77 extending (bulging) from the terminal end surface 73 toward the stopper 51. The shape of the extension portion 77 is a perfect circle concentric with the second elastic portion 70. The outer peripheral surface 91 of the flat plate 90 is embedded in the extension portion 77. The flat plate 90 is integrated with the terminal end surface 73 of the second elastic portion 70 and the extension portion 77 by, for example, integral molding, welding, or bonding.
[0118] Thus, the outer peripheral surface 91 of the flat plate 90 is embedded in the extension portion 77. Therefore, the flat plate 90 is integrated with the distal end surface 73 of the second elastic portion 70 and also with the extension portion 77. Therefore, the flat plate 90 can be more reliably prevented from peeling off from the distal end surface 73 of the second elastic portion 70.
[0119] The diameter d2C of the end 71a of the outer peripheral surface 71 of the second elastic portion 70 is larger than the outer diameter d5 of the flat plate 90. Figure 3-4 The diameter d2 of the end 71a of the illustrated embodiment 1 is large (d2C>d2=d5).
[0120] A second gap 82 is provided over the entire circumference between the outer circumferential surface 71 of the second elastic portion 70 and the inner circumferential surface 33a of the outer tube portion 33. The size δ2C of the second gap 82 is set in consideration of the elastic deformation of the entire elastic body 52 when the compressive load acts on the elastic body 52 from the stopper 51, and the size δ2C of the second gap 82 is larger than the size δ1 of the first gap 81. Furthermore, the size δ2C of the second gap 82 may be set smaller than the size δ1 of the first gap 81. Figure 3-4 The size δ2 of the second gap 82 in the illustrated embodiment 1 is smaller (δ2C<δ2).
[0121] More specifically, the diameter d2C of the end 71a of the outer peripheral surface 71 of the second elastic portion 70 is smaller than the diameter d1 of the outer peripheral surface 61 of the first elastic portion 60. The outer peripheral surface 71 of the second elastic portion 70 has an annular first groove 72. The first groove 72 is curvedly recessed from the end 61a of the outer peripheral surface 61 of the first elastic portion 60 toward the end surface 73 of the second elastic portion 70 over the entire circumference. The diameter d3 of the most recessed portion of the first groove 72 (see Fig.12 ) is smaller than the diameter d2C of the end 71a of the outer peripheral surface 71 of the second elastic portion 70.
[0122] Thus, the outer peripheral surface 71 of the second elastic portion 70 has the annular first groove 72 that is recessed over the entire circumference. Therefore, the second elastic portion 70 is more easily elastically deformed.
[0123] Next, refer to Fig.11 , Figure 13 to Figure 15 , the characteristics of the elastic body 52C are described. In addition, the characteristics of the elastic body 52C are the same as those described above. Figure 3 , Figures 5 to 8 The characteristics of the elastic body 52 of the first embodiment shown are the same, and therefore only an outline thereof will be described.
[0124] like Fig.11 As shown in FIG. 1 , the end surface 51a of the stopper 51 presses the end surface 73 of the second elastic portion 70 via the flat plate 90, whereby a compressive load fc (not shown) acts from the end surface 73 of the stopper 51 to the end surface 73 of the second elastic portion 70. As the compressive load fc increases, the first gap 81 and the second gap 82 decrease. The elastic body 52 continues to be compressed and deformed as a whole, and the inner peripheral surface 63 of the first elastic portion 60 is supported by contacting the outer peripheral surface 34a of the inner cylinder portion 34 (see FIG. 1 ). Fig.13 ). Fig.13 In the state shown, Figure 5 As in the first embodiment shown, the first load characteristic (low spring rate characteristic) is exhibited.
[0125] As the compressive load fc increases, the second gap 82 decreases. Therefore, the elastic body 52 continues to be compressed and deformed as a whole, and the outer peripheral surface 71 of the second elastic portion 70 is in contact with the inner peripheral surface 33a of the outer tube portion 33 and supported (see Fig.14 ). Fig.14 In the state shown, Figure 6 As in the first embodiment shown, there is a tendency to exhibit the second load characteristic (middle spring rate characteristic).
[0126] As the compressive load fc further increases, the inner peripheral surface 74 of the second elastic portion 70 bulges inward in the radial direction, and the extended portion 77 of the second elastic portion 70 bulges toward the stopper 51 (see Fig.15 ). That is, the compression deformation of the elastic body 52 reaches the limit. Fig.15 In the state shown, Figure 7 As in the first embodiment shown, there is a tendency to exhibit the third load characteristic (high spring rate characteristic).
[0127] The vehicle steering device 10C of the fourth embodiment is different from the above Figures 1 to 8 The vehicle steering system 10 of the first embodiment shown in the figure has the same functions and effects.
[0128] In addition, the vehicle steering devices 10 , 10A, 10B, and 10C according to the present invention are not limited to the embodiments as long as the functions and effects of the present invention can be obtained.
[0129] For example, in the present invention, the vehicle steering device 10 , 10A, 10B, 10C may be a so-called manual steering device that does not include the assist torque mechanism 40 as long as it has a configuration including only the steering system 20 .
[0130] In addition, the vehicle steering device 10, 10A, 10B, 10C can also be a so-called steer-by-wire steering device in which the steering wheel 21 and the steering shaft 26 are mechanically separated, a steering actuator (not shown) generates steering power according to the control amount of the steering wheel 21, and the steering power is transmitted to the steering shaft 26.
[0131] Furthermore, the vehicle steering devices 10 , 10A, 10B, and 10C may be a structure in which any two or more of them are appropriately combined.
[0132] Industrial Applicability
[0133] The vehicle steering device 10 , 10A, 10B, 10C of the present invention is suitable for installation in a vehicle.
[0134] Description of symbols
[0135] 10, 10A, 10B, 10C: Steering device for vehicle;
[0136] 26: steering shaft;
[0137] 26a: shaft end (end) of the steering shaft;
[0138] 30: Shell;
[0139] 32: opening;
[0140] 33: Outer cylinder part (first cylinder part);
[0141] 33a: inner circumferential surface of the outer cylinder;
[0142] 33b: open end of the outer tube (open end surface of the outer tube);
[0143] 34: inner cylinder portion (second cylinder portion);
[0144] 34a: outer peripheral surface of the inner cylinder (conical surface of the inner cylinder);
[0145] 34b: open end of the inner tube (open end surface of the inner tube);
[0146] 34c: inner circumferential surface of the inner cylinder;
[0147] 50: Mitigation device;
[0148] 51: stopper;
[0149] 52, 52A, 52B: elastic body;
[0150] 60: first elastic portion;
[0151] 61: outer peripheral surface of the first elastic portion;
[0152] 61a: end of the outer peripheral surface of the first elastic portion;
[0153] 62: bottom surface of the first elastic portion;
[0154] 63: inner peripheral surface (conical surface) of the first elastic portion;
[0155] 63a: end of the inner circumferential surface of the first elastic portion;
[0156] 64: end of the first elastic portion;
[0157] 70: second elastic portion;
[0158] 71: outer peripheral surface of the second elastic portion;
[0159] 72: First slot;
[0160] 73: terminal end surface of the second elastic portion;
[0161] 74: inner circumferential surface of the second elastic portion;
[0162] 74a: the end of the inner circumferential surface of the second elastic portion;
[0163] 75: Second slot;
[0164] 77: extension;
[0165] 81: First gap;
[0166] 82: Second gap;
[0167] 90: Flat plate;
[0168] L1: Length from the bottom to the open end of the inner tube;
[0169] L2: Length from the bottom to the open end of the outer tube;
[0170] δ1: the size of the first gap;
[0171] δ2, δ2C: the size of the second gap.
Claims
1. A vehicle steering device, comprising: A steering axis that can move in the vehicle width direction; a stopper, which is arranged at the end of the steering shaft; a housing extending in the vehicle width direction and capable of accommodating the steering shaft, wherein an opening portion of an end portion of the housing in the vehicle width direction is formed by an outer cylindrical portion on a radially outer side, an inner cylindrical portion on a radially inner side, and an annular and flat bottom surface closing one end of the outer cylindrical portion and one end of the inner cylindrical portion, so as to be annular and open toward the stopper and have a U-shaped cross section, wherein a length from the bottom surface to an open end of the inner cylindrical portion is shorter than a length from the bottom surface to an open end of the outer cylindrical portion; and An elastic body, which is composed of an annular elastic one-piece molded part, in which the steering shaft is inserted in a manner that allows it to move in the vehicle width direction, and the one-piece molded part is composed of the following parts: an annular first elastic part, which has a length equal to the length from the bottom surface to the open end of the inner tube part, is embedded in the opening part, and is supported by the inner circumference of the outer tube part and the bottom surface over the entire surface, and has a first gap throughout the entire circumference between the first elastic part and the outer circumference of the inner tube part; and an annular second elastic part, which extends from the first elastic part toward the stopper, and has a second gap larger than the first gap throughout the entire circumference between the second elastic part and the inner circumference of the outer tube part.
2. The vehicle steering device according to claim 1, wherein: The outer peripheral surface of the second elastic portion has an annular first groove that is recessed over the entire circumference.
3. The vehicle steering device according to claim 1 or 2, wherein: The outer peripheral surface of the inner cylinder portion is a tapered surface that tapers from the bottom surface toward the open end of the inner cylinder portion. A size of the first gap between the outer circumferential surface of the inner cylinder portion and the inner circumferential surface of the first elastic portion is constant.
4. The vehicle steering device according to claim 3, wherein: The inner peripheral surface of the second elastic portion is a tapered surface along an extension line of the tapered surface of the first elastic portion, and has an annular second groove that is recessed over the entire circumference.
5. The vehicle steering device according to any one of claims 1 to 4, wherein: An annular flat plate is provided at least at a portion of the distal end surface of the second elastic portion that contacts the stopper.
6. A vehicle steering device, comprising: A steering axis that can move in the vehicle width direction; a stopper, which is arranged at the end of the steering shaft; a housing extending in the vehicle width direction and capable of accommodating the steering shaft, wherein an opening portion of an end portion of the housing in the vehicle width direction is formed by an outer cylindrical portion on a radially outer side, an inner cylindrical portion on a radially inner side, and an annular and flat bottom surface closing one end of the outer cylindrical portion and one end of the inner cylindrical portion, so as to be annular and open toward the stopper and have a U-shaped cross section, wherein a length from the bottom surface to an open end of the inner cylindrical portion is shorter than a length from the bottom surface to an open end of the outer cylindrical portion; and An elastic body, which is composed of an annular elastic one-piece molded part, in which the steering shaft is inserted in a manner that allows it to move in the vehicle width direction, and the one-piece molded part is composed of the following parts: an annular first elastic part, which has a length equal to the length from the bottom surface to the open end of the inner tube part, is embedded in the opening part, and is supported by the inner peripheral surface of the outer tube part and the bottom surface in its entirety, and has a first gap throughout the entire circumference between the first elastic part and the outer peripheral surface of the inner tube part; and an annular second elastic part, which extends from the first elastic part toward the stopper, and has a second gap larger than the first gap throughout the entire circumference between the second elastic part and the inner peripheral surface of the outer tube part, The outer peripheral surface of the second elastic part has an annular first groove, and the first groove is concave in a curved shape over the entire circumference from the end of the outer peripheral surface of the first elastic part toward the end surface of the second elastic part. The outer peripheral surface of the inner cylinder portion is a tapered surface that tapers from the bottom surface toward the open end of the inner cylinder portion, and the edge between the outer peripheral surface of the inner cylinder portion and the open end of the inner cylinder portion is an arc-shaped surface, The size of the first gap between the outer circumferential surface of the inner cylinder and the inner circumferential surface of the first elastic portion is fixed. The inner peripheral surface of the second elastic portion is a tapered surface along the extension line of the tapered surface of the first elastic portion, and has an annular second groove that is recessed over the entire circumference. The boundary between the inner circumferential surface of the first elastic portion and the inner circumferential surface of the second elastic portion is an arc-shaped surface extending over the entire circumference. An annular flat plate is provided at least at a portion of the distal end surface of the second elastic portion that contacts the stopper.
7. The vehicle steering device according to claim 5 or 6, wherein: The second elastic portion has an extension portion extending from the end surface toward the stopper, The outer peripheral surface of the flat plate is buried in the extension portion.