WO2018235830A1

WO2018235830A1 - Steering device and intermediate shaft

Info

Publication number: WO2018235830A1
Application number: PCT/JP2018/023345
Authority: WO
Inventors: 誠一森山; 圭佑中尾; 哲也狩野; 高橋　正樹
Original assignee: 日本精工株式会社
Priority date: 2017-06-20
Filing date: 2018-06-19
Publication date: 2018-12-27

Abstract

This steering device is provided with: a first universal joint; a second universal joint which is arranged in a more anterior position than the first universal joint; and an intermediate shaft which is positioned between the first universal joint and the second universal joint. The intermediate shaft is provided with a first shock absorbing part which has a groove in the outer circumferential surface.

Description

Steering device and intermediate shaft

The present invention relates to a steering device and an intermediate shaft.

The vehicle is provided with a steering device as a device for transmitting an operation of a steering wheel of an operator (driver) to the wheels. There is known a steering device that makes it difficult to transmit an impact to a steering wheel when a vehicle collision occurs. For example, Patent Document 1 describes an intermediate shaft having a tubular bellows. According to Patent Document 1, the impact is absorbed by the deformation of the bellows at the time of the primary collision.

JP 2005-145164 A

However, the production of tubular bellows requires dedicated and expensive equipment. Furthermore, in order to change the deformation characteristics of the bellows in accordance with the individually determined shock absorption performance, it is necessary to change the mold. For this reason, there has been a demand for an intermediate shaft which can be easily manufactured and whose deformation characteristics can be easily changed.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a steering device which absorbs an impact by an intermediate shaft which can be easily manufactured and whose deformation characteristics can be easily changed.

In order to achieve the above object, a steering apparatus according to an aspect of the present disclosure includes a first universal joint, a second universal joint disposed on the front side of the first universal joint, the first universal joint, and the first universal joint. An intermediate shaft located between the two universal joints, and the intermediate shaft includes a first shock absorbing portion having a groove in an outer circumferential surface.

Thereby, since the first impact absorbing portion can be formed by cutting or the like, no mold is required when forming the first impact absorbing portion. Therefore, the formation of the first impact absorbing portion is facilitated. Further, the deformation characteristics of the first impact absorbing portion change in accordance with the shape of the groove of the first impact absorbing portion. Since it is easy to change the shape of the groove by changing the cutting range, it is easy to adjust the deformation characteristics of the first shock absorber. Thus, the steering device can absorb the impact by means of the intermediate shaft which can be easily manufactured and whose deformation characteristics can be easily changed.

As a desirable mode of the steering device, the intermediate shaft is a solid member.

Thereby, the intermediate shaft can be easily manufactured and the strength can be improved.

As a desirable mode of the steering apparatus, the intermediate shaft includes a first shaft which is a solid member, and a cylindrical second shaft which is releasably connected to the first shaft, and the first shaft is The first shock absorber is provided.

Thereby, the second shaft moves relative to the first shaft at the time of the primary collision. The steering device can absorb an impact by the friction generated between the first shaft and the second shaft.

As a desirable mode of the steering apparatus, the first shaft includes a first fitting portion having a serration on an outer peripheral surface, and the second shaft includes a second fitting portion having a serration on an inner peripheral surface, One fitting portion fits into the second fitting portion, and the maximum diameter of the first impact absorbing portion is smaller than the minimum diameter of the first fitting portion.

Thereby, when the second shaft moves relative to the first shaft, the serrations of the first impact absorbing portion and the second fitting portion are less likely to interfere with each other. For this reason, the steering device can suppress the variation in the shock absorbing capability of the intermediate shaft.

As a desirable mode of the steering device, the intermediate shaft includes a first shaft which is a hollow member whose inner diameter is constant over the entire axial length, and the first shaft includes the first impact absorbing portion.

Thus, the intermediate shaft can be easily manufactured and reduced in weight.

As a desirable mode of the steering device, the first shaft includes a second impact absorbing portion having an outer diameter smaller than the outer diameter of the first impact absorbing portion at a position corresponding to the bottom of the groove.

Thus, when a large torque acts on the intermediate shaft, energy is absorbed by the deformation of the second impact absorbing portion. On the other hand, deformation of the first impact absorbing portion is suppressed. For this reason, the designed deformation characteristics of the first shock absorber are maintained. As a result, when a vehicle collision occurs, the intermediate shaft can exhibit a predetermined shock absorbing capability.

As a desirable mode of the steering device, at least a part of the surface of the first shock absorber facing the groove has a first arc in a cross section obtained by cutting the first shaft in a plane perpendicular to the radial direction, At least a portion of the surface of the second impact absorbing portion draws a second arc, and the radius of curvature of the second arc is larger than the radius of curvature of the first arc.

Thus, when bending stress occurs in the intermediate shaft, stress concentration is more likely to occur in the first impact absorbing portion than in the second impact absorbing portion. Therefore, the intermediate shaft bends not from the second impact absorbing portion but from the first impact absorbing portion. Therefore, when a vehicle collision occurs, the intermediate shaft can exhibit a predetermined shock absorbing capability.

As a desirable mode of the steering device, the minimum thickness of the second impact absorbing portion is 10% or more and 20% or less of the outer diameter of the second impact absorbing portion.

Thereby, the buckling of the second impact absorbing portion is suppressed and the second impact absorbing portion is easily twisted. For this reason, the shock absorbing ability of the intermediate shaft is improved.

As a desirable mode of the steering device, the intermediate shaft includes a cylindrical second shaft which is releasably connected to the first shaft.

As a desirable mode of the steering device, the first impact absorbing portion includes a plurality of the grooves, and the grooves are annular.

Thus, when bending stress acts on the intermediate shaft, stress concentration occurs in the plurality of portions of the first impact absorbing portion. For this reason, the range of the deformed portion of the first impact absorbing portion tends to be large, so that the impact absorbing capability of the intermediate shaft is improved. Furthermore, since the groove is annular, it is difficult to limit the bending direction of the intermediate shaft.

As a desirable mode of a steering device, the above-mentioned slot is helical.

Thus, when bending stress acts on the intermediate shaft, stress concentration occurs in the plurality of portions of the first impact absorbing portion. Therefore, the deformation of the first impact absorbing portion tends to be large, and the impact absorbing capability of the intermediate shaft is improved. Furthermore, since the groove is spiral, it is difficult to limit the bending direction of the intermediate shaft.

As a desirable mode of the steering apparatus, the maximum width of the groove is 1 mm or more and 3 mm or less, and in a cross section obtained by cutting the intermediate shaft in a plane perpendicular to the radial direction, the first impact absorbing portion facing the groove At least a portion of the surface draws an arc having a radius of curvature of 0.2 mm or more and 1.0 mm or less.

As a result, extreme stress concentration does not occur in the first impact absorbing portion, and the first impact absorbing portion is easily bent.

As a desirable mode of the steering apparatus, the width of the groove is reduced toward the bottom of the groove.

As a result, when bending stress occurs in the intermediate shaft, stress concentration tends to occur.

An intermediate shaft according to an aspect of the present disclosure is an intermediate shaft used in a steering apparatus, and includes a first impact absorbing portion having a groove on an outer circumferential surface.

Thereby, since the first impact absorbing portion can be formed by cutting or the like, no mold is required when forming the first impact absorbing portion. Therefore, the formation of the first impact absorbing portion is facilitated. Further, the deformation characteristics of the first impact absorbing portion change in accordance with the shape of the groove of the first impact absorbing portion. Since it is easy to change the shape of the groove by changing the cutting range, it is easy to adjust the deformation characteristics of the first shock absorber. Thus, the intermediate shaft can be easily manufactured and can easily change its deformation characteristics.

According to the present invention, it is possible to provide a steering device that absorbs shock with an intermediate shaft which can be easily manufactured and whose deformation characteristics can be easily changed.

FIG. 1 is a schematic view of a steering apparatus according to the first embodiment. FIG. 2 is a perspective view of the steering device of the first embodiment. FIG. 3 is a side view of the intermediate shaft of the first embodiment. FIG. 4 is a cross-sectional view taken along line AA in FIG. FIG. 5 is an enlarged view of the periphery of the groove in FIG. FIG. 6 is a perspective view of the intermediate shaft after bending. FIG. 7 is a side view of the shock absorber in the intermediate shaft of the first modification of the first embodiment. FIG. 8 is an enlarged view of the periphery of the groove in the intermediate shaft of the second modified example of the first embodiment. FIG. 9 is a perspective view of the steering device of the second embodiment. FIG. 10 is a side view of the intermediate shaft of the second embodiment. FIG. 11 is a cross-sectional view taken along the line BB in FIG. FIG. 12 is an enlarged view of the periphery of the groove in FIG. FIG. 13 is a cross-sectional view taken along the line CC in FIG. FIG. 14 is a perspective view of the intermediate shaft after bending. FIG. 15 is a perspective view of the steering device of the third embodiment. FIG. 16 is a side view of the intermediate shaft of the third embodiment. FIG. 17 is a cross-sectional view taken along the line DD in FIG. FIG. 18 is an enlarged view of the periphery of the groove in FIG. FIG. 19 is a perspective view of the intermediate shaft after bending. FIG. 20 is a graph showing the relationship between displacement and load when the intermediate shaft of the comparative example is bent. FIG. 21 is a graph showing the relationship between displacement and load when the intermediate shaft of the third embodiment bends. FIG. 22 is a side view of an impact absorbing portion in the intermediate shaft of the first modified example of the third embodiment. FIG. 23 is a side view showing an intermediate shaft of a second modified example of the third embodiment. FIG. 24 is a cross-sectional view taken along line EE in FIG. FIG. 25 is a side view of an intermediate shaft of a third modified example of the third embodiment. FIG. 26 is a cross-sectional view along the line FF in FIG. FIG. 27 is a cross-sectional view of a groove located at the center of the shock absorbing portion. FIG. 28 is a cross-sectional view of a groove located at the end of the shock absorbing part. FIG. 29 is a perspective view of the steering device of the fourth embodiment. FIG. 30 is a perspective view of the intermediate shaft of the fourth embodiment. FIG. 31 is a cross-sectional view of the intermediate shaft of the fourth embodiment. FIG. 32 is an enlarged cross-sectional view of a first impact absorbing portion and a lower fitting portion of the lower shaft. FIG. 33 is an enlarged cross-sectional view of the periphery of the groove of the first impact absorbing portion. FIG. 34 is an enlarged cross-sectional view of a second impact absorbing portion of the lower shaft. FIG. 35 is a front view of an example of the stopper. FIG. 36 is a front view of an example of a stopper. FIG. 37 is a front view of an example of a stopper. FIG. 38 is a front view of an example of a stopper. FIG. 39 is a front view of an example of a stopper. FIG. 40 is a front view of an example of the stopper. FIG. 41 is a cross-sectional view taken along the line GG in FIG. FIG. 42 is a cross-sectional view taken along the line HH in FIG. FIG. 43 is a perspective view of the intermediate shaft after the lower shaft has entered the upper shaft. FIG. 44 is a perspective view of the intermediate shaft after the lower shaft is bent. FIG. 45 is a perspective view of the steering device of the fifth embodiment. FIG. 46 is a perspective view of the intermediate shaft of the fifth embodiment. FIG. 47 is a cross-sectional view of the intermediate shaft of the fifth embodiment. FIG. 48 is an enlarged cross-sectional view of the first impact absorbing portion and the first fitting portion of the first shaft. FIG. 49 is an enlarged cross-sectional view of the periphery of the groove of the first impact absorbing portion. FIG. 50 is an enlarged sectional view of a second impact absorbing portion of the first shaft. 51 is a cross-sectional view taken along line II in FIG. 52 is a cross-sectional view taken along line JJ in FIG. FIG. 53 is a perspective view of the intermediate shaft after the first shaft has entered the second shaft. FIG. 54 is a perspective view of the intermediate shaft after the first shaft is bent. FIG. 55 is an enlarged cross-sectional view of a peripheral portion of a groove of a first impact absorbing portion in a first modified example of the fifth embodiment. FIG. 56 is an enlarged cross-sectional view of a first impact absorbing portion in a second modified example of the fifth embodiment. FIG. 57 is a cross-sectional view of the intermediate shaft of the third modified example of the fifth embodiment. FIG. 58 is a perspective view of the steering device of the sixth embodiment. FIG. 59 is a side view of the intermediate shaft of the sixth embodiment. FIG. 60 is a cross-sectional view of the intermediate shaft of the sixth embodiment. FIG. 61 is an enlarged view of the first shock absorber in FIG. 60. Figure 62 is an enlarged view of the groove of Figure 60; FIG. 63 is an enlarged view of a second shock absorber shown in FIG. 60. FIG. 64 is a side view of the intermediate shaft after bending. FIG. 65 is a perspective view of an intermediate shaft of a first modified example of the sixth embodiment. FIG. 66 is a cross-sectional view of the intermediate shaft of the first modified example of the sixth embodiment. FIG. 67 is an enlarged cross-sectional view of a first impact absorbing portion and a first fitting portion of a first shaft. FIG. 68 is a cross-sectional view taken along line KK in FIG. 69 is a cross-sectional view taken along line LL in FIG. FIG. 70 is a perspective view of the intermediate shaft after the first shaft is in the second shaft. FIG. 71 is a perspective view of the intermediate shaft after the first shaft is bent. FIG. 72 is a cross-sectional view of the intermediate shaft of the second modified example of the sixth embodiment. FIG. 73 is an enlarged cross-sectional view of a peripheral portion of a groove of a first impact absorbing portion in a third modified example of the sixth embodiment. FIG. 74 is an enlarged cross-sectional view of a first shock absorber in a fourth modification of the sixth embodiment.

Hereinafter, the present invention will be described in detail with reference to the drawings. The present invention is not limited by the following embodiments (hereinafter referred to as embodiments). Further, constituent elements in the following embodiments include those which can be easily conceived by those skilled in the art, those substantially the same, and so-called equivalent ranges. Furthermore, the components disclosed in the following embodiments can be combined as appropriate.

First Embodiment
FIG. 1 is a schematic view of a steering apparatus according to the first embodiment. FIG. 2 is a perspective view of the steering device of the first embodiment. As shown in FIG. 1, in the steering device 80, the steering wheel 81, the steering shaft 82, the steering force assist mechanism 83, the first universal joint 84, and the intermediate shaft 85 are transmitted in the order of transmission of the force applied by the operator. And a second universal joint 86, and is joined to the pinion shaft 87. In the following description, the front of the vehicle on which the steering device 80 is mounted is described simply as the front, and the rear of the vehicle is described as the rear.

As shown in FIG. 1, the steering shaft 82 includes an input shaft 82a and an output shaft 82b. One end of the input shaft 82a is connected to the steering wheel 81, and the other end of the input shaft 82a is connected to the output shaft 82b. Further, one end of the output shaft 82b is connected to the input shaft 82a, and the other end of the output shaft 82b is connected to the first universal joint 84.

As shown in FIG. 1, the intermediate shaft 85 connects the first universal joint 84 and the second universal joint 86. One end of the intermediate shaft 85 is connected to the first universal joint 84, and the other end is connected to the second universal joint 86. One end of the pinion shaft 87 is connected to the second universal joint 86, and the other end of the pinion shaft 87 is connected to the steering gear 88. The first universal joint 84 and the second universal joint 86 are, for example, cardan joints. The rotation of the steering shaft 82 is transmitted to the pinion shaft 87 via the intermediate shaft 85. That is, the intermediate shaft 85 rotates with the steering shaft 82.

As shown in FIG. 1, the steering gear 88 includes a pinion 88 a and a rack 88 b. The pinion 88 a is coupled to the pinion shaft 87. The rack 88 b meshes with the pinion 88 a. The steering gear 88 converts the rotational motion transmitted to the pinion 88a into a linear motion at the rack 88b. The rack 88 b is connected to the tie rod 89. The movement of the rack 88b changes the angle of the wheel.

As shown in FIG. 1, the steering force assist mechanism 83 includes a reduction gear 92 and an electric motor 93. The reduction gear 92 is, for example, a worm reduction gear. The torque generated by the electric motor 93 is transmitted to the worm wheel via the worm in the reduction gear 92 to rotate the worm wheel. The reduction gear 92 increases the torque generated by the electric motor 93 by the worm and the worm wheel. Then, the reduction gear 92 applies an auxiliary steering torque to the output shaft 82b. That is, the steering device 80 is a column assist system.

As shown in FIG. 1, the steering device 80 includes an ECU (Electronic Control Unit) 90, a torque sensor 94, and a vehicle speed sensor 95. The electric motor 93, the torque sensor 94, and the vehicle speed sensor 95 are electrically connected to the ECU 90. The torque sensor 94 outputs the steering torque transmitted to the input shaft 82 a to the ECU 90 by CAN (Controller Area Network) communication. The vehicle speed sensor 95 detects the traveling speed (vehicle speed) of the vehicle body on which the steering device 80 is mounted. The vehicle speed sensor 95 is provided on the vehicle body and outputs the vehicle speed to the ECU 90 by CAN communication.

The ECU 90 controls the operation of the electric motor 93. The ECU 90 obtains signals from the torque sensor 94 and the vehicle speed sensor 95, respectively. Electric power is supplied to the ECU 90 from the power supply device 99 (for example, an on-board battery) while the ignition switch 98 is on. The ECU 90 calculates the assist steering command value based on the steering torque and the vehicle speed. The ECU 90 adjusts the power value supplied to the electric motor 93 based on the assist steering command value. The ECU 90 acquires information on the induced voltage from the electric motor 93 or information output from a resolver or the like provided in the electric motor 93. The control of the electric motor 93 by the ECU 90 reduces the force required to operate the steering wheel 81.

FIG. 3 is a side view of the intermediate shaft of the first embodiment. FIG. 4 is a cross-sectional view taken along line AA in FIG. FIG. 5 is an enlarged view of the periphery of the groove in FIG.

The intermediate shaft 85 is a substantially cylindrical solid member. For example, the intermediate shaft 85 is formed of S35C which is carbon steel for machine structure (SC material). As shown in FIG. 3, the intermediate shaft 85 includes a base 11, a shock absorber 15, and a base 19.

The base 11 is connected to a first universal joint 84. The diameter of the base 11 is constant. The shock absorber 15 is located in front of the base 11. The shock absorbing portion 15 is located at the center of the intermediate shaft 85 in the axial direction of the intermediate shaft 85. The base 19 is connected to the second universal joint 86. The diameter of the base 19 is constant and equal to the diameter of the base 11.

In the following description, the axial direction of the intermediate shaft 85 is simply described as the axial direction, and the direction orthogonal to the axial direction is described as the radial direction. 4 and 5 are cross sections of the intermediate shaft 85 cut in a plane orthogonal to the radial direction.

As shown in FIG. 4, the shock absorption unit 15 includes a plurality of grooves 3 and a plurality of protrusions 4. The groove 3 is annular. The grooves 3 are formed by cutting, for example. The plurality of grooves 3 are arranged at equal intervals in the axial direction. The protrusion 4 is located between the two grooves 3. The diameter D1 of the shock absorbing portion 15 at the position corresponding to the convex portion 4 is equal to the diameters of the base 11 and the base 19.

As shown in FIG. 5, the shock absorbing portion 15 has a first side surface 31, a second side surface 33, a bottom surface 35, a first connection surface 36 and a second connection surface 37 as surfaces facing the groove 3. ,including. The first side surface 31 and the second side surface 33 are perpendicular to the axial direction. That is, the second side surface 33 is parallel to the first side surface 31. The bottom surface 35 is located between the first side surface 31 and the second side surface 33. The first side surface 31 is located rearward with respect to the bottom surface 35, and the second side surface 33 is located forward with respect to the bottom surface 35. The bottom surface 35 is a curved surface. The first connection surface 36 is a curved surface connecting the first side surface 31 and the bottom surface 35. The second connection surface 37 is a curved surface connecting the second side surface 33 and the bottom surface 35.

The maximum width W of the groove 3 is preferably 1 mm or more and 3 mm or less. The maximum width W of the groove 3 is set so that the shock absorber 15 does not break when the shock absorber 15 is bent. The maximum width W of the groove 3 is set such that, when the shock absorbing portion 15 is bent, adjacent convex portions 4 are in contact before the shock absorbing portion 15 breaks. In the cross section shown in FIG. 5, the first connection surface 36 and the second connection surface 37 draw the same arc. The radius of curvature C1 of the arc drawn by the first connection surface 36 and the second connection surface 37 is preferably 0.2 mm or more and 1.0 mm or less. For example, the curvature radius C1 in the first embodiment is 0.3 mm.

The shock absorber 15 is designed to transmit a torque of, for example, 300 Nm. When the intermediate shaft 85 is formed of S35C, the diameter D2 of the impact absorbing portion 15 at the position corresponding to the bottom of the groove 3 is about 14 mm or more and 16 mm or less. The diameter D2 is determined by the depth H of the groove 3 shown in FIG.

FIG. 6 is a perspective view of the intermediate shaft after bending. A load is applied to the steering gear 88 at the time of a primary collision of the vehicle. The load applied to the steering gear 88 generates bending stress on the intermediate shaft 85. At this time, stress concentration occurs in the first connection surface 36 and the second connection surface 37, so that the shock absorbing portion 15 is bent starting from the first connection surface 36 and the second connection surface 37. One side in the radial direction of the groove 3 expands, and the other side in the radial direction of the groove 3 contracts. On the side where the groove 3 is contracted, the convex portion 4 is in contact with the adjacent convex portion 4. The bent intermediate shaft 85 enters the clearance of the peripheral parts of the intermediate shaft 85. The impact absorbing portion 15 bends to absorb the impact due to the collision. As a result, the shock transmitted to the steering wheel 81 is reduced.

Since the shock absorbing portion 15 includes the plurality of grooves 3, when bending stress acts on the intermediate shaft 85, stress concentration occurs at a plurality of portions of the shock absorbing portion 15. As a result, the range of the deformed portion of the shock absorbing portion 15 tends to be large, so that the shock absorbing ability of the intermediate shaft 85 is improved.

The groove 3 of the impact absorbing portion 15 may not necessarily have the above-described shape. For example, the first connection surface 36 and the second connection surface 37 may be connected without the bottom surface 35 interposed therebetween. That is, in a cross section obtained by cutting the intermediate shaft 85 in a plane perpendicular to the radial direction, the surface of the shock absorber 15 at a position corresponding to the bottom of the groove 3 may draw a semicircle. Also, the first connection surface 36 and the second connection surface 37 may not be present. That is, the first side surface 31 and the second side surface 33 may be directly connected to the bottom surface 35. This description is also applicable to the other embodiments described below.

The number of grooves 3 provided in the impact absorbing portion 15 may not necessarily be as shown in the drawing. The shock absorber 15 may have at least one groove 3. This description is also applicable to the other embodiments described below.

The diameter D1 of the impact absorbing portion 15 at the position corresponding to the convex portion 4 may not necessarily be equal to the diameter of the base 11. The diameter D1 may be larger than the diameter D2 of the shock absorber 15 at a position corresponding to at least the bottom of the groove 3. The diameter D 1 may be smaller than the diameter of the base 11 or larger than the diameter of the base 11. This description is also applicable to the other embodiments described below.

As described above, the steering apparatus 80 includes the first universal joint 84, the second universal joint 86 disposed on the front side of the first universal joint 84, the first universal joint 84, and the second universal joint 86. And an intermediate shaft 85, which is a solid member connecting the two. The intermediate shaft 85 includes an impact absorbing portion 15 having a groove 3 on the outer peripheral surface.

As a result, no mold is required when forming the shock absorbing portion 15, so that the shock absorbing portion 15 can be easily formed. Further, the deformation characteristics of the shock absorbing portion 15 change in accordance with the shape of the groove 3 of the shock absorbing portion 15. Since it is easy to change the shape of the groove 3, it is easy to adjust the deformation characteristics of the impact absorbing portion 15. Thus, the steering device 80 can absorb the impact by means of the intermediate shaft 85 which can be easily manufactured and whose deformation characteristics can be easily changed.

Further, in the steering device 80, the impact absorbing portion 15 is provided with a plurality of grooves 3. The grooves 3 are annular.

As a result, when bending stress acts on the intermediate shaft 85, stress concentration occurs at a plurality of portions of the impact absorbing portion 15. As a result, the range of the deformed portion of the shock absorbing portion 15 tends to be large, so that the shock absorbing ability of the intermediate shaft 85 is improved. Furthermore, since the groove 3 is annular, the bending direction of the intermediate shaft 85 is unlikely to be limited.

Further, in the steering device 80, the maximum width W of the groove 3 is 1 mm or more and 3 mm or less. In a cross section obtained by cutting the intermediate shaft 85 in a plane perpendicular to the radial direction, at least a part of the surface of the shock absorbing portion 15 facing the groove 3 has an arc having a curvature radius of 0.2 mm or more and 1.0 mm or less Draw.

As a result, extreme stress concentration does not occur in the shock absorbing portion 15, and the shock absorbing portion 15 is easily bent.

First Modified Example of First Embodiment
FIG. 7 is a side view of the shock absorber in the intermediate shaft of the first modification of the first embodiment. In addition, the same code | symbol is attached | subjected to the same component as what was demonstrated in embodiment mentioned above, and the overlapping description is abbreviate | omitted.

As shown in FIG. 7, the impact absorbing portion 15 </ b> A of the first modified example of the first embodiment includes a groove 3 </ b> A. The groove 3A is helical. The description of the maximum width W and the curvature radius C1 of the groove 3 described above can be applied to the groove 3A.

As a result, when bending stress acts on the intermediate shaft 85, stress concentration occurs at a plurality of portions of the impact absorbing portion 15A. Therefore, the deformation of the shock absorbing portion 15A is likely to be large, so that the shock absorbing ability of the intermediate shaft 85 is improved. Furthermore, since the groove 3A is helical, the bending direction of the intermediate shaft 85 is unlikely to be limited.

Second Modified Example of First Embodiment
FIG. 8 is an enlarged view of the periphery of the groove in the intermediate shaft of the second modified example of the first embodiment. In addition, the same code | symbol is attached | subjected to the same component as what was demonstrated in embodiment mentioned above, and the overlapping description is abbreviate | omitted.

The impact absorbing portion 15B of the second modified example of the first embodiment includes a plurality of grooves 3B. As shown in FIG. 8, the impact absorbing portion 15B has a first side 31B, a second side 33B, a bottom 35B, a first connection surface 36B, and a second connection surface 37B as surfaces facing the groove 3B. ,including. The bottom surface 35B is located between the first side 31B and the second side 33B. The first connection surface 36B is a curved surface connecting the first side surface 31B and the bottom surface 35B. The second connection surface 37B is a curved surface connecting the second side surface 33B and the bottom surface 35B. The distance between the first side surface 31B and the second side surface 33B decreases toward the bottom surface 35B. That is, the width of the groove 3B decreases toward the bottom of the groove 3B.

As a result, when bending stress acts on the intermediate shaft 85, stress concentration tends to occur.

The configurations of the first modification of the first embodiment and the second modification of the first embodiment are also applicable to the second and subsequent embodiments.

Second Embodiment
FIG. 9 is a perspective view of the steering device of the second embodiment. FIG. 10 is a side view of the intermediate shaft of the second embodiment. FIG. 11 is a cross-sectional view taken along the line BB in FIG. FIG. 12 is an enlarged view of the periphery of the groove in FIG. FIG. 13 is a cross-sectional view taken along the line CC in FIG. In addition, the same code | symbol is attached | subjected to the same component as what was demonstrated in embodiment mentioned above, and the overlapping description is abbreviate | omitted.

The intermediate shaft 85C is a substantially cylindrical solid member. For example, the intermediate shaft 85C is formed of S35C which is carbon steel for machine structure (SC material). As shown in FIG. 10, the intermediate shaft 85C includes a base 11C, a first shock absorber 15C, a base 16C, a second shock absorber 17C, and a base 19C.

The base 11C is connected to the first universal joint 84. The diameter of the base 11C is constant. The first shock absorber 15C is located in front of the base 11C. The first impact absorbing portion 15C is located at the center of the intermediate shaft 85C in the axial direction of the intermediate shaft 85C. The base 16C is located in front of the first shock absorber 15C. The second shock absorber 17C is located in front of the base 16C. The second impact absorbing portion 17C is located forward of the center of the intermediate shaft 85C in the axial direction of the intermediate shaft 85C. The base 19C is connected to the second universal joint 86. The diameter of the base 19C is constant and equal to the diameter of the base 11C.

As shown in FIG. 11, the first impact absorbing portion 15C includes a plurality of grooves 3C and a plurality of convex portions 4C. The groove 3C is annular. The grooves 3C are formed by cutting, for example. The plurality of grooves 3C are arranged at equal intervals in the axial direction. The convex portion 4C is located between the two grooves 3C. The diameter D1C of the first shock absorber 15C at a position corresponding to the convex portion 4C is equal to the diameters of the base 11C, the base 16C, and the base 19C.

As shown in FIG. 12, the first impact absorbing portion 15C has a first side 31C, a second side 33C, a bottom 35C, a first connection surface 36C, and a second connection surface as surfaces facing the groove 3C. And 37C. The first side surface 31C and the second side surface 33C are perpendicular to the axial direction. That is, the second side surface 33C is parallel to the first side surface 31C. The bottom surface 35C is located between the first side 31C and the second side 33C. The first side surface 31C is located rearward with respect to the bottom surface 35C, and the second side surface 33C is located forward with respect to the bottom surface 35C. The bottom surface 35C is a curved surface. The first connection surface 36C is a curved surface connecting the first side surface 31C and the bottom surface 35C. The second connection surface 37C is a curved surface connecting the second side surface 33C and the bottom surface 35C.

The maximum width WC of the groove 3C is preferably 1 mm or more and 3 mm or less. The maximum width WC of the groove 3C is set so that the first shock absorber 15C does not break when the first shock absorber 15C bends. The maximum width WC of the groove 3C is set such that, when the first impact absorbing portion 15C is bent, adjacent convex portions 4C are in contact before the first impact absorbing portion 15C breaks. In the cross section shown in FIG. 12, the first connection surface 36C and the second connection surface 37C draw the same arc (hereinafter referred to as a first arc). The radius of curvature C1C of the first arc is preferably 0.2 mm or more and 1.0 mm or less. For example, the curvature radius C1C in the second embodiment is 0.3 mm.

The first shock absorber 15C is designed to transmit, for example, a torque of 300 Nm. When the intermediate shaft 85C is formed of S35C, the diameter D2C of the first shock absorber 15C at a position corresponding to the bottom of the groove 3C is about 14 mm or more and 16 mm or less. The diameter D2C is determined by the depth HC of the groove 3C shown in FIG.

FIG. 14 is a perspective view of the intermediate shaft after bending. A load is applied to the steering gear 88 at the time of a primary collision of the vehicle. The load applied to the steering gear 88 generates bending stress on the intermediate shaft 85C. At this time, stress concentration occurs in the first connection surface 36C and the second connection surface 37C, and the first impact absorbing portion 15C is bent starting from the first connection surface 36C and the second connection surface 37C. One side of the groove 3C in the radial direction expands, and the other side of the groove 3C in the radial direction contracts. On the side where the groove 3C is contracted, the convex portion 4C is in contact with the adjacent convex portion 4C. The bent intermediate shaft 85C enters the clearance of the peripheral parts of the intermediate shaft 85C. By bending the first impact absorbing portion 15C, the impact due to the collision is absorbed. As a result, the shock transmitted to the steering wheel 81 is reduced.

Since the first impact absorbing portion 15C includes the plurality of grooves 3C, when bending stress acts on the intermediate shaft 85C, stress concentration occurs in the plurality of portions of the first impact absorbing portion 15C. For this reason, the range of the deformed portion of the first impact absorbing portion 15C is likely to be large, so that the impact absorbing capability of the intermediate shaft 85C is improved.

As shown in FIG. 13, the second impact absorbing portion 17C includes a small diameter portion 175C, a first connection portion 171C, and a second connection portion 179C. The small diameter portion 175C is cylindrical. The diameter D3C of the small diameter portion 175C is smaller than the diameter D2C shown in FIG. The axial length LC of the small diameter portion 175C is larger than the maximum width WC of the groove 3C. The first connection portion 171C connects the base portion 16C and the small diameter portion 175C. The second connection portion 179C connects the base 19C and the small diameter portion 175C. In the cross section shown in FIG. 13, the surfaces of the first connection portion 171C and the second connection portion 179C draw the same arc (hereinafter, referred to as a second arc). The radius of curvature C2C of the second arc is larger than the radius of curvature C1C of the first arc. The curvature radius C2C is preferably 5 mm or more. For example, the radius of curvature C2C is 8 mm.

The second impact absorbing portion 17C is designed to be deformed by a torque of, for example, 150 Nm or more and 250 Nm or less. When the intermediate shaft 85C is formed of S35C, the diameter D3C is about 13 mm or more and 15.5 mm or less. For example, in the second embodiment, the diameter D3C is 13 mm.

The intermediate shaft 85C may generate bending stress due to the primary collision, and may receive a large torque (twisting force) when the vehicle runs on a curb or the like. Therefore, the intermediate shaft 85C is required to be able to suppress damage when receiving a large torque and to absorb an impact at the time of a primary collision.

In the intermediate shaft 85C of the second embodiment, the diameter D3C is smaller than the diameter D2C. For this reason, the second impact absorbing portion 17C is deformed (twisted) when the vehicle rides on a curb or the like. The deformation of the second impact absorbing portion 17C absorbs the energy input to the intermediate shaft 85C. Since energy is absorbed by the second impact absorbing portion 17C, deformation of the first impact absorbing portion 15C is suppressed.

On the other hand, in the middle shaft 85C of the second embodiment, the curvature radius C2C is larger than the curvature radius C1C. For this reason, when bending stress is generated in the intermediate shaft 85C at the time of the primary collision, the first impact absorbing portion 15C, not the second impact absorbing portion 17C, is deformed (bent).

As described above, the steering device 80C includes the first universal joint 84, the second universal joint 86 disposed forward of the first universal joint 84, the first universal joint 84, and the second universal joint 86. And an intermediate shaft 85C which is a solid member connecting the two. The intermediate shaft 85C has a first impact absorbing portion 15C having a groove 3C on the outer peripheral surface, and a second impact absorbing portion having a diameter D3C smaller than the diameter D2C of the first impact absorbing portion 15C at a position corresponding to the bottom of the groove 3C. And 17C.

As a result, no mold is required when forming the first impact absorbing portion 15C, so the formation of the first impact absorbing portion 15C is facilitated. Also, the deformation characteristics of the first impact absorbing portion 15C change in accordance with the shape of the groove 3C of the first impact absorbing portion 15C. Since it is easy to change the shape of the groove 3C, it is easy to adjust the deformation characteristics of the first shock absorber 15C. Therefore, the steering device 80C can absorb an impact by the intermediate shaft 85C which can be easily manufactured and can easily change its deformation characteristics.

Furthermore, when a large torque acts on the intermediate shaft 85C, energy is absorbed by the deformation of the second impact absorbing portion 17C. On the other hand, the deformation of the first shock absorber 15C is suppressed. For this reason, the designed deformation characteristics of the first shock absorber 15C are maintained. As a result, when a collision of a vehicle occurs, the intermediate shaft 85C can exhibit a predetermined shock absorbing capability.

Further, in a cross section obtained by cutting the intermediate shaft 85C in a plane perpendicular to the radial direction, at least a portion of the surface of the first shock absorber 15C facing the groove 3C draws a first arc, and the second shock absorber 17C At least a portion of the surface of the circle draws a second arc. The radius of curvature C2C of the second arc is larger than the radius of curvature C1C of the first arc.

As a result, when bending stress acts on the intermediate shaft 85C, stress concentration tends to occur in the first impact absorbing portion 15C. Therefore, the intermediate shaft 85C bends not from the second impact absorbing portion 17C but from the first impact absorbing portion 15C. Therefore, when a collision of a vehicle occurs, the intermediate shaft 85C can exhibit a predetermined shock absorbing capability.

Third Embodiment
FIG. 15 is a perspective view of the steering device of the third embodiment. FIG. 16 is a side view of the intermediate shaft of the third embodiment. FIG. 17 is a cross-sectional view taken along the line DD in FIG. FIG. 18 is an enlarged view of the periphery of the groove in FIG. In addition, the same code | symbol is attached | subjected to the same component as what was demonstrated in embodiment mentioned above, and the overlapping description is abbreviate | omitted.

The intermediate shaft 85D is a substantially cylindrical solid member. For example, the intermediate shaft 85D is formed of S35C which is carbon steel for machine structure (SC material). As shown in FIG. 16, the intermediate shaft 85D includes a base 11D, a shock absorber 15D, and a base 19D.

The base 11D is connected to the first universal joint 84. The diameter of the base 11D is constant. The shock absorbing portion 15D is located in front of the base 11D. The shock absorbing portion 15D is located at the center of the intermediate shaft 85D in the axial direction of the intermediate shaft 85D. The base 19D is connected to the second universal joint 86. The diameter of the base 19D is constant and equal to the diameter of the base 11D.

In the following description, the axial direction of the intermediate shaft 85D is simply described as the axial direction, and the direction orthogonal to the axial direction is described as the radial direction. FIGS. 17 and 18 are cross sections of the intermediate shaft 85D cut in a plane orthogonal to the radial direction.

As shown in FIG. 17, the impact absorbing portion 15D includes a plurality of grooves 3D and a plurality of convex portions 4D. The grooves 3D are annular. The grooves 3D are formed by cutting, for example. The plurality of grooves 3D are arranged at equal intervals in the axial direction. The protrusion 4D is located between the two grooves 3D. The diameter D1 of the impact absorbing portion 15D at the position corresponding to the convex portion 4D is equal to the diameters of the base 11D and the base 19D.

As shown in FIG. 17, the plurality of grooves 3D are a groove 3aD, a groove 3bD, a groove 3cD, a groove 3dD, a groove 3eD, a groove 3fD, a groove 3gD, a groove 3hD, a groove 3iD, and a groove 3jD and a groove 3kD. Grooves 3aD to 3kD line up from the rear end to the front end of the impact absorbing portion 15D. The groove 3fD is located at the center of the shock absorber 15D in the axial direction.

The shape of the groove 3kD is the same as the shape of the groove 3aD. The shape of the groove 3jD is the same as the shape of the groove 3bD. The shape of the groove 3iD is the same as the shape of the groove 3cD. The shape of the groove 3hD is the same as the shape of the groove 3dD. The shape of the groove 3gD is the same as the shape of the groove 3eD. As shown in FIG. 17, the diameter of the impact absorbing portion 15D at a position corresponding to the groove 3aD to the bottom of the groove 3kD is from the diameter DaD to the diameter DkD. Among the diameter DaD to the diameter DkD, the diameter DfD is the largest, and the diameter DaD and the diameter DkD are the smallest. The diameter of the shock absorber 15D at a position corresponding to the bottom of one groove 3D is the shock absorber at a position corresponding to the bottom of another groove 3D located axially on the center side of the intermediate shaft 85D than the groove 3D. Less than 15D diameter.

As shown in FIG. 18, the shock absorbing portion 15D has a first side 31D, a second side 33D, a bottom 35D, a first connection surface 36D, and a second connection surface 37D as surfaces facing the groove 3D. ,including. FIG. 18 shows the groove 3fD, but the grooves 3aD to 3eD and the grooves 3gD to 3kD have the same structure except for the depth. The first side surface 31D and the second side surface 33D are perpendicular to the axial direction. That is, the second side surface 33D is parallel to the first side surface 31D. The bottom surface 35D is located between the first side 31D and the second side 33D. The first side surface 31D is located rearward with respect to the bottom surface 35D, and the second side surface 33D is located forward with respect to the bottom surface 35D. The bottom surface 35D is a curved surface. The first connection surface 36D is a curved surface connecting the first side surface 31D and the bottom surface 35D. The second connection surface 37D is a curved surface connecting the second side surface 33D and the bottom surface 35D.

The maximum width WD of the groove 3D is preferably 1 mm or more and 3 mm or less. The maximum width WD of the groove 3D is set so that the shock absorber 15D does not break when the shock absorber 15D is bent. The maximum width WD of the groove 3D is set such that, when the shock absorbing portion 15D is bent, adjacent convex portions 4D are in contact before the shock absorbing portion 15D breaks. In the cross section shown in FIG. 18, the first connection surface 36D and the second connection surface 37D draw the same arc. The curvature radius C1D of the arc drawn by the first connection surface 36D and the second connection surface 37D is preferably 0.2 mm or more and 1.0 mm or less. For example, the curvature radius C1D in the present embodiment is 0.3 mm.

The shock absorber 15D is designed to transmit, for example, a torque of 300 Nm. When the intermediate shaft 85D is formed of S35C, the diameter DaD and the diameter DkD are about 14 mm or more and 16 mm or less.

FIG. 19 is a perspective view of the intermediate shaft after bending. A load is applied to the steering gear 88 at the time of a primary collision of the vehicle. The load applied to the steering gear 88 generates bending stress on the intermediate shaft 85D. At this time, stress concentration occurs in the first connection surface 36D and the second connection surface 37D, so that the impact absorbing portion 15D is bent starting from the first connection surface 36D and the second connection surface 37D. One side of the groove 3D in the radial direction expands, and the other side of the groove 3D in the radial direction contracts. On the side where the groove 3D is contracted, the convex portion 4D is in contact with the adjacent convex portion 4D. The bent intermediate shaft 85D enters the clearance of the peripheral parts of the intermediate shaft 85D. By the impact absorbing portion 15D being bent, the impact due to the collision is absorbed. As a result, the shock transmitted to the steering wheel 81 is reduced.

Since the impact absorbing portion 15D includes the plurality of grooves 3D, when bending stress acts on the intermediate shaft 85D, stress concentration occurs in a plurality of portions of the impact absorbing portion 15D. As a result, the range of the deformed portion of the shock absorbing portion 15D tends to be large, so that the shock absorbing ability of the intermediate shaft 85D is improved.

FIG. 20 is a graph showing the relationship between displacement and load when the intermediate shaft of the comparative example is bent. FIG. 21 is a graph showing the relationship between displacement and load when the intermediate shaft of the third embodiment bends. 20 and 21 are conceptual diagrams for explaining the difference between the comparative example and the third embodiment.

The comparative example is different from the third embodiment in that all the grooves 3D have the same shape. That is, in the comparative example, the diameter of the impact absorbing portion 15D at a position corresponding to the bottom of the groove 3D is constant. The magnitude of the bending moment acting on the intermediate shaft 85D due to the load applied to the steering gear 88 varies depending on the axial position. The bending moment is maximum at the center of the intermediate shaft 85D in the axial direction and decreases toward the end. For this reason, in the comparative example, the load required to bend the end of the impact absorbing portion 15D is larger than the load required to bend the center of the impact absorbing portion 15D. As a result, as shown in FIG. 20, after the center of the shock absorbing portion 15D is bent, the load required to bend the shock absorbing portion 15D increases as the displacement of the shock absorbing portion 15D increases.

On the other hand, in the third embodiment, the diameter of the shock absorbing portion 15D at the position corresponding to the bottom of one groove 3D is the other one located axially on the center side of the intermediate shaft 85D than the groove 3D. The diameter is smaller than the diameter of the shock absorber 15D at a position corresponding to the bottom of the groove 3D. Therefore, the difference between the load required to bend the center of the impact absorbing portion 15D and the load required to bend the end of the impact absorbing portion 15D is reduced. As a result, as shown in FIG. 21, after a portion of the shock absorbing portion 15D is bent, the load required to bend the other portion of the shock absorbing portion 15D hardly changes. That is, variation in load required to deform the intermediate shaft 85D is suppressed.

The number of grooves 3D provided in the impact absorbing portion 15D may not necessarily be as shown in the drawing. The shock absorbing portion 15D may have at least two grooves 3D.

The diameter D1 of the impact absorbing portion 15D at the position corresponding to the convex portion 4D may not necessarily be equal to the diameter of the base 11D. The diameter D1 may be larger than the diameter DfD of the shock absorber 15D at a position corresponding to at least the bottom of the groove 3fD. The diameter D1 may be smaller than the diameter of the base 11D or larger than the diameter of the base 11D.

As described above, the steering device 80D includes the first universal joint 84, the second universal joint 86 disposed forward of the first universal joint 84, the first universal joint 84, and the second universal joint 86. And an intermediate shaft 85D which is a solid member connecting the two. The intermediate shaft 85D includes an impact absorbing portion 15D having a first groove (for example, a groove 3aD) and a second groove (for example, a groove 3fD) on the outer peripheral surface. The diameter (for example, diameter DfD) of impact absorbing portion 15D at the position corresponding to the bottom of the second groove is different from the diameter (for example, diameter DaD) of impact absorbing portion 15D at the position corresponding to the bottom of the first groove.

As a result, no mold is required when forming the impact absorbing portion 15D, so the formation of the impact absorbing portion 15D is facilitated. Further, the deformation characteristics of the shock absorbing portion 15D change according to the shape of the groove 3D of the shock absorbing portion 15D. Since it is easy to change the shape of the groove 3D, it is easy to adjust the deformation characteristics of the impact absorbing portion 15D. Accordingly, the steering device 80D can absorb an impact by means of the intermediate shaft 85D which can be easily manufactured and whose deformation characteristics can be easily changed.

Furthermore, in the steering device 80D, it is possible to make the section coefficient of the portion corresponding to the first groove of the impact absorbing portion 15D different from the section coefficient of the portion corresponding to the second groove. For this reason, adjustment of the bending stress in each cross section of impact-absorbing part 15D is possible.

In the steering device 80D, the second groove (for example, the groove 3fD) is located on the center side of the intermediate shaft 85D in the axial direction of the intermediate shaft 85D with respect to the first groove (for example, the groove 3aD). The diameter (for example, the diameter DfD) of the impact absorbing portion 15D at a position corresponding to the bottom of the second groove is larger than the diameter (for example, the diameter DaD) of the impact absorbing portion 15D at a position corresponding to the bottom of the first groove.

Therefore, the difference between the load required to bend the portion corresponding to the first groove of the impact absorbing portion 15D and the load required to bend the portion corresponding to the second groove of the impact absorbing portion 15D is reduced. Therefore, the variation in load required to deform the intermediate shaft 85D is suppressed.

Further, in the steering device 80D, the first groove (for example, the groove 3aD) and the second groove (for example, the groove 3fD) are annular.

This makes it difficult to limit the bending direction of the intermediate shaft 85D.

Further, in the steering device 80D, the maximum widths WD of the first groove (for example, the groove 3aD) and the second groove (for example, the groove 3fD) are 1 mm or more and 3 mm or less. In a cross section obtained by cutting the intermediate shaft 85D in a plane perpendicular to the radial direction, at least a part of the surface of the shock absorbing portion 15D facing the first groove and at least the surface of the shock absorbing portion 15D facing the second groove One part draws the circular arc whose curvature radius is 0.2 mm or more and 1.0 mm or less.

As a result, extreme stress concentration does not occur in the impact absorbing portion 15D, and the impact absorbing portion 15D is easily bent.

First Modification of Third Embodiment
FIG. 22 is a side view of an impact absorbing portion in the intermediate shaft of the first modified example of the third embodiment. In addition, the same code | symbol is attached | subjected to the same component as what was demonstrated in embodiment mentioned above, and the overlapping description is abbreviate | omitted.

As shown in FIG. 22, the impact absorbing portion 15E of the first modified example of the third embodiment includes a plurality of grooves 3aE. The plurality of grooves 3E include a groove 3aE, a groove 3bE, a groove 3cE, a groove 3dE, and a groove 3eE. The grooves 3aE to 3eE are each in a spiral shape. The grooves 3aE to 3eE may be connected or may be separate grooves. As shown in FIG. 22, the radius of the shock absorbing portion 15E at a position corresponding to the groove 3aE to the bottom of the groove 3eE is set from a radius RaE to a radius RaE. Among the radius RaE to the radius ReE, the radius RcE is the largest, and the radius RaE and the radius ReE are the smallest. The diameter of the shock absorber 15E at a position corresponding to the bottom of one groove 3E is the shock absorber at a position corresponding to the bottom of another groove 3E located axially on the center side of the intermediate shaft 85D with respect to the groove 3E. Less than 15E diameter. The description of the maximum width WD and the curvature radius C1D of the groove 3D described above can be applied to the groove 3aE to the groove 3eE.

This makes it difficult to limit the bending direction of the intermediate shaft 85E.

Second Modified Example of Third Embodiment
FIG. 23 is a side view showing an intermediate shaft of a second modified example of the third embodiment. FIG. 24 is a cross-sectional view taken along line EE in FIG. In addition, the same code | symbol is attached | subjected to the same component as what was demonstrated in embodiment mentioned above, and the overlapping description is abbreviate | omitted.

As shown in FIG. 23, the impact absorbing portion 15F in the second modification of the third embodiment is closer to the rear side than the center of the intermediate shaft 85F in the axial direction. More specifically, the front end of the shock absorbing portion 15F is located rearward of the center of the intermediate shaft 85F in the axial direction. The shock absorbing portion 15F includes a plurality of grooves 3F.

As shown in FIG. 24, the plurality of grooves 3F include grooves 3aF, grooves 3bF, grooves 3cF, grooves 3dF, grooves 3eF, and grooves 3fF. Grooves 3aF to 3fF are arranged from the rear end to the front end of the shock absorbing portion 15F. As shown in FIG. 24, the diameter of the shock absorbing portion 15F at the position corresponding to the groove 3aF to the bottom of the groove 3fF is set from the diameter DaF to the diameter DfF. Among the diameter DaF to the diameter DfF, the diameter DfF is the largest and the diameter DaF is the smallest. The diameter of the shock absorbing portion 15F at a position corresponding to the bottom of one groove 3F is the shock absorbing portion at a position corresponding to the bottom of another groove 3F located on the center side of the intermediate shaft 85F in the axial direction than the groove 3F. Less than 15F diameter.

Third Modified Example of Third Embodiment
FIG. 25 is a side view of an intermediate shaft of a third modified example of the third embodiment. FIG. 26 is a cross-sectional view along the line FF in FIG. FIG. 27 is a cross-sectional view of a groove located at the center of the shock absorbing portion. FIG. 28 is a cross-sectional view of a groove located at the end of the shock absorbing part. In addition, the same code | symbol is attached | subjected to the same component as what was demonstrated in embodiment mentioned above, and the overlapping description is abbreviate | omitted.

As shown in FIG. 25, the shock absorbing portion 15G of the third modified example of the third embodiment is located at the center of the intermediate shaft 85G in the axial direction. The shock absorbing portion 15G includes a plurality of grooves 3G.

As shown in FIG. 26, the plurality of grooves 3G are a groove 3aG, a groove 3bG, a groove 3cG, a groove 3dG, a groove 3eG, a groove 3fG, a groove 3gG, a groove 3hG, a groove 3iG, and a groove 3jG and grooves 3kG. A groove 3aG to a groove 3kG are axially aligned from the rear end to the front end of the shock absorbing portion 15G. The groove 3fG is located at the center of the shock absorbing portion 15G in the axial direction.

The shape of the groove 3kG is the same as the shape of the groove 3aG. The shape of the groove 3jG is the same as the shape of the groove 3bG. The shape of the groove 3iG is the same as the shape of the groove 3cG. The shape of the groove 3hG is the same as the shape of the groove 3dG. The shape of the groove 3gG is the same as the shape of the groove 3eG.

As shown in FIG. 27, the shock absorbing portion 15G includes a first connection surface 36fG and a second connection surface 37fG as a surface facing the groove 3fG. As shown in FIG. 28, the shock absorbing portion 15G includes a first connection surface 36aG and a second connection surface 37aG as surfaces facing the groove 3aG. The grooves 3bG to 3eG and the grooves 3gG to 3kG have the same configuration except for the shapes of the first connection surface and the second connection surface.

In the cross section shown in FIG. 27, the first connection surface 36fG and the second connection surface 37fG draw the same arc. The radius of curvature of the arc drawn by the first connection surface 36fG and the second connection surface 37fG is taken as the curvature radius CfG. In the cross section shown in FIG. 28, the first connection surface 36aG and the second connection surface 37aG draw the same arc. The curvature radius of the arc drawn by the first connection surface 36aG and the second connection surface 37aG is taken as a curvature radius CaG. Similarly, the radius of curvature of the arc drawn by the first connecting surface and the second connecting surface of the groove 3bG, the groove 3cG, the groove 3dG, the groove 3eD, the groove 3gG, the groove 3hG, the groove 3iG, the groove 3jG, and the groove 3kG is the radius of curvature CbG The radius of curvature CcG, the radius of curvature CdG, the radius of curvature CeG, the radius of curvature CgG, the radius of curvature ChG, the radius of curvature CiG, the radius of curvature CjG, and the radius of curvature CkG.

Among the curvature radius CaG to the curvature radius CkG, the curvature radius CfG is the largest, and the curvature radius CaG and the curvature radius CkG are the smallest. In the cross section shown in FIG. 26, the radius of curvature of the arc drawn by the surface of the shock absorbing portion 15G facing one groove 3G is the same as that of the other groove 3G located on the center side of the intermediate shaft 85G in the axial direction than the groove 3G. The radius of curvature of the arc drawn by the surface of the facing shock absorbing portion 15G is smaller than that of the arc. For example, from the curvature radius CaG, the curvature radius CkG is preferably 0.2 mm or more and 1.0 mm or less.

The shock absorber 15G is designed to transmit a torque of, for example, 300 Nm. When the intermediate shaft 85G is formed of S35C, the diameter D2D is about 14 mm or more and 16 mm or less. The diameter D2D is a diameter of the shock absorber 15G at a position corresponding to the bottom of the groove 3G. In a third variant of the third embodiment, the diameter D2D is constant.

As described above, the steering device 80D of the third modified example of the third embodiment includes the first universal joint 84, the second universal joint 86 disposed on the front side of the first universal joint 84, and the first universal joint 86. And an intermediate shaft 85G which is a solid member connecting the universal joint 84 and the second universal joint 86. The intermediate shaft 85G includes an impact absorbing portion 15G having a first groove (for example, a groove 3aG) and a second groove (for example, a groove 3fG) on the outer peripheral surface. In a cross section obtained by cutting the intermediate shaft 85G in a plane perpendicular to the radial direction, at least a portion of the surface of the shock absorbing portion 15G facing the first groove (for example, the first connection surface 36aG) draws a first arc, and the first At least a part of the surface of the shock absorbing portion 15G facing the two grooves (for example, the first connection surface 36fG) draws a second arc. The radius of curvature of the second arc (eg, radius of curvature CfG) is different from the radius of curvature of the first arc (eg, radius of curvature CaG).

Thereby, in the third modification of the third embodiment, the bending stress generated in the portion corresponding to the corner of the first groove of the impact absorbing portion 15G and the bending stress generated in the portion corresponding to the corner of the second groove And can be different. For this reason, adjustment of the bending stress in each cross section of impact-absorbing part 15G is possible.

In the third modification of the third embodiment, the second groove (for example, the groove 3fG) is located on the center side of the intermediate shaft 85G in the axial direction with respect to the first groove (for example, the groove 3aG). The radius of curvature (for example, radius of curvature CfG) of the second arc is larger than the radius of curvature (for example, radius of curvature CaG) of the first arc.

Therefore, the difference between the load required to bend the portion corresponding to the first groove of the impact absorbing portion 15G and the load required to bend the portion corresponding to the second groove of the impact absorbing portion 15G is reduced. Therefore, the variation in load required to deform the intermediate shaft 85G is suppressed.

Fourth Embodiment
FIG. 29 is a perspective view of the steering device of the fourth embodiment. FIG. 30 is a perspective view of the intermediate shaft of the fourth embodiment. FIG. 31 is a cross-sectional view of the intermediate shaft of the fourth embodiment. FIG. 32 is an enlarged cross-sectional view of a first impact absorbing portion and a lower fitting portion of the lower shaft. FIG. 33 is an enlarged cross-sectional view of the periphery of the groove of the first impact absorbing portion. FIG. 34 is an enlarged cross-sectional view of a second impact absorbing portion of the lower shaft. 35 to 40 are front views of an example of the stopper. FIG. 41 is a cross-sectional view taken along the line GG in FIG. FIG. 42 is a cross-sectional view taken along the line HH in FIG. In addition, the same code | symbol is attached | subjected to the same component as what was demonstrated in embodiment mentioned above, and the overlapping description is abbreviate | omitted.

As shown in FIG. 30, the intermediate shaft 85H includes a lower shaft 1H and an upper shaft 2H.

The lower shaft 1H is a substantially cylindrical solid member. For example, the lower shaft 1H is formed of S35C which is carbon steel for machine structure (SC material). As shown in FIG. 31, the lower shaft 1H includes a base 10H, a first shock absorber 15H, a stopper 16H, a base 11H, a second shock absorber (fuse) 12H, a base 13H, and a lower fitting. And a unit 17H.

As shown in FIGS. 30 and 31, the base 10H is fixed to the second universal joint 86. The diameter of the base 10H is constant. The first shock absorber 15H is located behind the base 10H. Further, the first impact absorbing portion 15H is located forward of the center of the lower shaft 1H in the axial direction of the lower shaft 1H.

The stopper 16H is located behind the first impact absorbing portion 15H in the axial direction of the lower shaft 1H. Further, the stopper 16H is located at a position slightly closer to the center of the lower shaft 1H in the axial direction of the lower shaft 1H. The base 11H is located behind the stopper 16H.

The second impact absorbing portion 12H is located rearward of the base 11H in the axial direction of the lower shaft 1H. The base 13H is located behind the second shock absorber 12H. The diameter of the base 13H is constant and equal to the diameters of the base 10H and the base 11H.

The lower fitting portion 17H is located at the rear end of the lower shaft 1H. The lower fitting portion 17H includes male splines (or male serrations) 17aH on the outer peripheral surface. The male spline (or male serration) 17aH meshes with a female spline (or female serration) 21aH described later.

Further, as shown in FIG. 31, the lower fitting portion 17H has a recess 170H on the end face on the rear side.

In the axial direction of the lower shaft 1H, the base 10H, the base 11H, the second impact absorbing portion (fuse) 12H, the base 13H, the stopper 16H, the first impact absorbing portion 15H, and the lower fitting portion 17H And may be provided. In this case, the base 10H and the base 11H are integrally continuous, and the second shock absorber 12H is located on the front side of the lower shaft 1H.

In the following description, the axial direction of the lower shaft 1H is simply described as the axial direction, and the direction orthogonal to the axial direction is described as the radial direction. 31 to 34 are cross sections obtained by cutting the lower shaft 1H in a plane orthogonal to the radial direction.

As shown in FIG. 32, the first impact absorbing portion 15H includes a plurality of grooves 3H and a plurality of convex portions 4H. The groove 3H is annular. The grooves 3H are formed by cutting, for example. The plurality of grooves 3H are arranged at equal intervals in the axial direction. The protrusion 4H is located between the two grooves 3H. The diameter D1H of the first impact absorbing portion 15H at the position corresponding to the convex portion 4H is equal to the diameters of the base 10H, the base 11H and the base 13H. Further, the diameter D1H is smaller than the minimum diameter D4H of the lower fitting portion 17H. The minimum diameter D4H is the diameter of the lower fitting portion 17H at a position corresponding to the valley of the male spline 17aH.

As shown in FIG. 33, the first impact absorbing portion 15H has a first side 31H, a second side 33H, a bottom 35H, a first connecting surface 36H, and a second connecting surface as surfaces facing the groove 3H. And 37H. The first side surface 31H and the second side surface 33H are perpendicular to the axial direction.

That is, the second side surface 33H is parallel to the first side surface 31H. The bottom surface 35H is located between the first side 31H and the second side 33H. The first side surface 31H is located rearward with respect to the bottom surface 35H, and the second side surface 33H is located forward with respect to the bottom surface 35H. The bottom surface 35H is a curved surface. The first connection surface 36H is a curved surface connecting the first side surface 31H and the bottom surface 35H. The second connection surface 37H is a curved surface connecting the second side surface 33H and the bottom surface 35H.

The maximum width WH of the groove 3H is preferably 1 mm or more and 3 mm or less. The maximum width WH of the groove 3H is set so that the first impact absorbing portion 15H does not break when the first impact absorbing portion 15H is bent. The maximum width WH of the groove 3H is set such that, when the first impact absorbing portion 15H is bent, adjacent convex portions 4H are in contact before the first impact absorbing portion 15H breaks. In the cross section shown in FIG. 33, the first connection surface 36H and the second connection surface 37H draw the same arc (hereinafter, referred to as a first arc). The radius of curvature C1H of the first arc is preferably 0.2 mm or more and 1.0 mm or less. For example, the curvature radius C1H in the fourth embodiment is 0.3 mm.

The first shock absorber 15H is designed to transmit, for example, a torque of 300 Nm. When the lower shaft 1H is formed of S35C, the diameter D2H of the first impact absorbing portion 15H at the position corresponding to the bottom of the groove 3H is about 14 mm or more and 16 mm or less. The diameter D2H is determined by the depth HH of the groove 3H shown in FIG.

As shown in FIG. 34, the second impact absorbing portion 12H includes a small diameter portion 125H, a first connection portion 121H, and a second connection portion 129H. The small diameter portion 125H is cylindrical. The diameter D3 of the small diameter portion 125H is smaller than the diameter D2H shown in FIG. The axial length LH of the small diameter portion 125H is larger than the maximum width WH of the groove 3H. The first connection portion 121H connects the base 11H and the small diameter portion 125H. The second connection portion 129H connects the base 13H and the small diameter portion 125H. In the cross section shown in FIG. 34, the surfaces of the first connection portion 121H and the second connection portion 129H draw the same arc (hereinafter, referred to as a second arc). The curvature radius C2 of the second arc is larger than the curvature radius C1H of the first arc. The curvature radius C2 is preferably 5 mm or more. For example, the curvature radius C2 is 8 mm.

The second impact absorbing portion 12H is designed to be deformed by, for example, a torque of about 150 Nm to 250 Nm. When the intermediate shaft 85H is formed of S35C, the diameter D3 of the small diameter portion 125H is about 13 mm or more and 15.5 mm or less. For example, in the fourth embodiment, the diameter D3 is 13 mm.

As shown in FIG. 31, the stopper 16H has a function of restricting the relative displacement amount (collapse amount) in the axial direction. The stopper 16H is a member formed on the lower shaft 1H in order to restrict the distance (collapse stroke S) in which the lower shaft 1H can move in the axial direction with respect to the upper shaft 2H. For example, the stopper 16H has an outer diameter larger than the minimum diameter D4H of the lower fitting portion 17H shown in FIG.

In the fourth embodiment, as an example of the stopper 16H, an annular retaining ring made of metal of the same quality as that of the lower shaft 1H is formed at a predetermined position of the collapse stroke S in the axial direction. The stopper 16H may be a stopper member integrated by welding to the lower shaft 1H. Alternatively, the stopper 16H may be configured by a combination of a C-shaped retaining ring or an E-shaped retaining ring and another member. The fixing method of the stopper 16H can be appropriately adopted, and it is not particularly limited.

For example, the members shown in FIGS. 35 to 40 can be used.

The one shown in FIG. 35 is made by bending and forming an elastic cross-sectional circular wire rod, and the ring-shaped retaining ring main body having an annular shape and the radial outward direction from both circumferential end portions of the retaining ring main body And a pair of locking rings.

The one shown in FIG. 36 is generally called a C-shaped ring, and is manufactured by punching and forming a metal plate. The one shown in FIG. 36 includes a notched annular retaining ring main body, and a pair of ear portions projecting radially outward from both end portions in the circumferential direction of the retaining ring main body.

The one shown in FIG. 37 is generally called an E-shaped ring, and is manufactured by punching and forming a metal plate. The one shown in FIG. 37 includes a notched annular retaining ring main body, and three claws projecting radially inward from both circumferential end portions of the retaining ring main body and the circumferential center.

The one shown in FIG. 38 is provided with an annular portion and a plurality of tongues projecting radially inward from a plurality of circumferential positions of the annular portion.

The one shown in FIG. 39 is made of, for example, a material having a lower shear resistance than synthetic resins and iron-based materials such as copper and aluminum. The whole of what is shown in FIG. 39 is configured to be an annulus.

Similar to the one shown in FIG. 39, the one shown in FIG. 40 is made of a material having a lower shear resistance than an iron-based material. The one shown in FIG. 40 is configured in a pin shape.

Furthermore, as the stopper 16H, one having a shape other than an annular or shaft shape can be used. Various fixing structures conventionally known such as welding, bonding, press-fitting, caulking, screwing, etc. can be adopted as a structure for fixing the stopper 16H to the lower shaft 1H.

When the lower shaft 1H moves by the collapsing stroke S with respect to the upper shaft 2H at the time of the primary collision by such a stopper 16H, the stopper 16H abuts on the front end of the upper fitting portion 21H, and the movement of the lower shaft 1H stops. As a result, the lower shaft 1H is displaced in the axial direction and expands and contracts so as to absorb an impact load, but is stopped by the stopper 16H. By applying a load to the first impact absorbing portion 15H, it is avoided that an excessive load is applied to the upper shaft 2H side.

Therefore, by optimizing the collapse stroke S in accordance with the degree of impact at the time of collision, the timing of contraction and bending of the intermediate shaft can be controlled.

As shown in FIG. 31, the upper shaft 2H is cylindrical. For example, the upper shaft 2H is formed of carbon steel tube for mechanical structure (STKM material (Carbon Steel Tubes for Machine Structural Purposes)). The upper shaft 2H includes an upper fitting portion 21H, a large diameter portion 23H, and a base 25H.

The upper fitting portion 21H is disposed at the front end of the upper shaft 2H. The lower fitting portion 17H is inserted into the upper fitting portion 21H. The upper fitting portion 21H is provided with a female spline 21aH on the inner circumferential surface. The female splines 21aH mesh with the male splines 17aH.

As shown in FIG. 41, the outer shape of the lower fitting portion 17H draws a circle in a cross section orthogonal to the axial direction. In the cross section shown in FIG. 41, the outer shape of the upper fitting portion 21H draws an ellipse. As shown in FIG. 42, the outer shape of the lower fitting portion 17H draws an ellipse in a cross section different from that of FIG. 41 among the cross sections orthogonal to the axial direction. In the cross section shown in FIG. 42, the outer shape of the upper fitting portion 21H draws a circle. The shapes of the upper fitting portion 21H of FIG. 41 and the lower fitting portion 17H of FIG. 42 are exaggerated for the sake of description, and are different from the actual shapes. In practice, all the teeth of the female spline 21aH are respectively located between the two teeth of the male spline 17aH. That is, the teeth of the female spline 21aH located on the left and right sides of FIG. 41 are not in contact with the teeth of the male spline 17aH, but are located between the two teeth of the male spline 17aH. The teeth of the female splines 21aH located on the upper side and the lower side of FIG. 42 are not in contact with the teeth of the male splines 17aH, but are located between the two teeth of the male splines 17aH.

When assembling the intermediate shaft 85H, a part of the lower fitting portion 17H is inserted into the upper fitting portion 21H. Then, the lower fitting portion 17H and the upper fitting portion 21H are pressed from two directions at a position corresponding to the recess 170H. Thereafter, the lower fitting portion 17H is further pushed into the upper fitting portion 21H. Thereby, cross-sectional shapes shown in FIGS. 41 and 42 are formed. In addition, such a connection method of lower fitting part 17H and upper fitting part 21H may be called elliptical fitting.

Moreover, although the connection method called such elliptical fitting enables relative displacement when a strong impact load is applied in the axial direction of the intermediate shaft 85H, another embodiment which enables relative displacement in the light axial direction There are connection methods using so-called resin-coated sliders and rolling elements (balls and rollers).

In the connection method using the resin-coated slider, for example, the outer peripheral surface of the lower fitting portion 17H is coated with a synthetic resin, and further, grease is applied to be fitted to the lower fitting portion 17H. As a result, it is possible to reduce wear of the contact portion between the lower fitting portion 17H and the upper fitting portion 21H and to reduce the frictional resistance.

Note that the outer surface of at least one of the lower fitting portion 17H and the upper fitting portion 21H may be coated with a lubricating coating with either or both of synthetic resin and grease.

In addition, the lubricating film may be coated with resin or grease on the outer shape of at least one of the lower fitting portion 17H and the upper fitting portion 21H.

In the connection method using rolling elements, for example, a rolling element in which a ball or a roller and a combination of a ball and a roller are interposed between the lower fitting portion 17H and the upper fitting portion 21H. As a result, it is possible to reduce wear of a contact portion of the upper fitting portion 21H with the lower fitting portion 17H and to reduce frictional resistance.

The movement of the upper fitting portion 21H with respect to the lower fitting portion 17H is restricted by the friction generated at the contact portion between the lower fitting portion 17H and the upper fitting portion 21H. That is, in normal use (when no collision occurs), the upper fitting portion 21H does not move relative to the lower fitting portion 17H. On the other hand, when a predetermined axial load is applied to the upper shaft 2H at the time of a collision, the upper fitting portion 21H moves by the collapse stroke S relative to the lower fitting portion 17H. The predetermined load is, for example, about 1 kN or more and 3 kN or less.

That is, the upper shaft 2H is connected to the lower shaft 1H so as to be separated from the lower shaft 1H at the time of a collision. The impact is absorbed by the friction between the upper fitting portion 21H and the lower fitting portion 17H. The impact is absorbed by the friction between the upper fitting portion 21H and the lower fitting portion 17H.

The large diameter portion 23H is disposed in front of the upper fitting portion 21H. The outer diameter of the large diameter portion 23H is constant. The outer diameter of the large diameter portion 23H is larger than the outer diameter of the upper fitting portion 21H.

The base 25H is disposed at the front end of the upper shaft 2H. The base 25H is fixed to the second universal joint 86. The outer diameter of the base 25H is constant. The outer diameter of the base 25H is equal to the outer diameter of the upper fitting portion 21H.

FIG. 43 is a perspective view of the intermediate shaft after the lower shaft has entered the upper shaft. FIG. 44 is a perspective view of the intermediate shaft after the lower shaft is bent.

When the vehicle collides, a load is applied to the steering gear 88. The load applied to the steering gear 88 is transmitted to the upper shaft 2H via the second universal joint 86. If all of the front of the vehicle collides with the collision object (in the case of a full wrap collision), the upper shaft 2H is often subjected to an axial load. In the case of a full wrap collision, as shown in FIG. 43, the upper shaft 2H moves to the stopper 16H with respect to the lower shaft 1H to absorb the shock (indicated by arrow P in FIG. 43). As a result, the shock transmitted to the steering wheel 81 is reduced.

On the other hand, when a part of the front of the vehicle hits a collision target (in the case of an offset collision), a further force is applied (indicated by arrow Q in FIG. 44) and a non-axial load is applied to the upper shaft 2H. There are many. Therefore, the upper shaft 2H can not move straight with respect to the lower shaft 1H. In the case of an offset collision, bending stress occurs in the intermediate shaft 85H.

At this time, stress concentration occurs in the first connection surface 36H and the second connection surface 37H, whereby the first impact absorbing portion 15H is bent as shown in FIG. 44 starting from the first connection surface 36H and the second connection surface 37H. . One side of the groove 3H in the radial direction expands, and the other side of the groove 3H in the radial direction contracts. On the side where the groove 3H is contracted, the convex portion 4H is in contact with the adjacent convex portion 4H. The bent intermediate shaft 85H enters the clearance of the peripheral parts of the intermediate shaft 85H. By bending the first impact absorbing portion 15H, an impact due to a collision is absorbed. As a result, the shock transmitted to the steering wheel 81 is reduced.

Since the first impact absorbing portion 15H includes the plurality of grooves 3H, when bending stress acts on the intermediate shaft 85H, stress concentration occurs in the plurality of portions of the first impact absorbing portion 15H. For this reason, the range of the deformed portion of the first impact absorbing portion 15H tends to be large, so that the impact absorbing ability of the intermediate shaft 85H is improved.

The intermediate shaft 85H may generate bending stress due to the primary collision, and may receive a large torque (twisting force) when the vehicle runs on a curb or the like. Therefore, the intermediate shaft 85H is required to be able to suppress damage when receiving a large torque and to absorb an impact at the time of a primary collision.

In the intermediate shaft 85H of the fourth embodiment, the diameter D3 is smaller than the diameter D2H. For this reason, the second impact absorbing portion 12H is deformed (twisted) when the vehicle rides on a curb or the like. The energy input to the intermediate shaft 85H is absorbed by the deformation of the second impact absorbing portion 12H. Since energy is absorbed by the second impact absorbing portion 12H, deformation of the first impact absorbing portion 15H is suppressed.

Thus, by providing the second impact absorbing portion 12H in the twisting direction in a portion close to the lower fitting portion 17H, in view of the behavior of the vehicle body at the time of a collision, the transmission of the impact to the first impact absorbing portion 15H can be performed. It can be relaxed as appropriate.

On the other hand, in the intermediate shaft 85H of the fourth embodiment, the curvature radius C2 is larger than the curvature radius C1H. Therefore, when bending stress is generated in the intermediate shaft 85H at the time of the primary collision, the first impact absorbing portion 15H, not the second impact absorbing portion 12H, is deformed (bent).

At this time, the second impact absorbing portion 12H moves into the upper shaft 2H since the lower shaft 1H moves to the stopper 16H which is the collapse stroke S.

The groove 3H of the first impact absorbing portion 15H may not necessarily have the above-described shape. For example, the first connection surface 36H and the second connection surface 37H may be connected without the bottom surface 35H. That is, in a cross section obtained by cutting the intermediate shaft 85H in a plane perpendicular to the radial direction, the surface of the first shock absorber 15H at a position corresponding to the bottom of the groove 3H may draw a semicircle. In addition, the first connection surface 36H and the second connection surface 37H may not be necessary. That is, the first side surface 31H and the second side surface 33H may be directly connected to the bottom surface 35H.

The number of grooves 3H provided in the first impact absorbing portion 15H may not necessarily be as shown in the drawing. The first shock absorber 15H may have at least one groove 3H.

The diameter D1H of the first impact absorbing portion 15H at the position corresponding to the convex portion 4H may not necessarily be equal to the diameter of the base 11H. The diameter D1H should be at least larger than the diameter D2H of the first shock absorber 15H at a position corresponding to the bottom of the groove 3H and smaller than the minimum diameter D4H of the lower fitting portion 17H. The diameter D1H may be smaller than the diameter of the base 11H or larger than the diameter of the base 11H.

As described above, the steering device 80H includes the first universal joint 84, the second universal joint 86 disposed on the front side of the first universal joint 84, the first universal joint 84, and the second universal joint 86. And an intermediate shaft 85H connecting the two. The intermediate shaft 85H includes a lower shaft 1H which is a solid member, and a cylindrical upper shaft 2H which is detachably coupled to the lower shaft 1H. The lower shaft 1H includes a first impact absorbing portion 15H having a groove 3H on the outer peripheral surface. Further, the lower shaft is provided with a stopper capable of restricting the amount of axial collapse of the lower shaft with respect to the upper shaft.

As a result, no mold is required when forming the first impact absorbing portion 15H, so the formation of the first impact absorbing portion 15H is facilitated. Further, the deformation characteristics of the first impact absorbing portion 15H change in accordance with the shape of the groove 3H of the first impact absorbing portion 15H. Since it is easy to change the shape of the groove 3H, it is easy to adjust the deformation characteristics of the first impact absorbing portion 15H. Therefore, the steering device 80H can absorb an impact by the intermediate shaft 85H which can be easily manufactured and can easily change its deformation characteristics.

Furthermore, the upper shaft 2H moves relative to the lower shaft 1H at the time of the primary collision. The steering device 80H can absorb an impact by the friction generated between the lower shaft 1H and the upper shaft 2H.

The lower shaft 1H further includes a lower fitting portion 17H having a male spline 17aH on the outer peripheral surface. The upper shaft 2H includes an upper fitting portion 21H having a female spline 21aH on the inner circumferential surface. The lower fitting portion 17H fits into the upper fitting portion 21H. The maximum outer diameter (diameter D1H) of the first impact absorbing portion 15H is smaller than the minimum diameter D4H of the lower fitting portion 17H.

As a result, when the upper shaft 2H moves relative to the lower shaft 1H, the first impact absorbing portion 15H and the female spline 21aH of the upper fitting portion 21H do not easily interfere with each other. Therefore, the steering device 80H can suppress the variation in the shock absorbing capability of the intermediate shaft 85H.

Further, in the steering device 80H, the first impact absorbing portion 15H includes a plurality of grooves 3H. The grooves 3H are annular.

As a result, when bending stress acts on the intermediate shaft 85H, stress concentration occurs in a plurality of portions of the first impact absorbing portion 15H. For this reason, the range of the deformed portion of the first impact absorbing portion 15H tends to be large, so that the impact absorbing ability of the intermediate shaft 85H is improved. Furthermore, since the groove 3H is annular, the bending direction of the intermediate shaft 85H is unlikely to be limited.

In the steering device 80H, the maximum width WH of the groove 3H is 1 mm or more and 3 mm or less. In a cross section obtained by cutting the intermediate shaft 85H in a plane perpendicular to the radial direction, at least a part of the surface of the first shock absorber 15H facing the groove 3H has a curvature radius of 0.2 mm or more and 1.0 mm or less Draw an arc.

As a result, extreme stress concentration does not occur in the first impact absorbing portion 15H, and the first impact absorbing portion 15H is easily bent.

As described above, in the steering apparatus according to the fourth embodiment, in the case of a primary collision or the like which has collided with a curb, the fuse in the torsion direction absorbs the impact in the portion near the upper fitting portion 21H. . In the case of a full wrap collision, the lower shaft 1H moves to the stopper 16H with respect to the upper shaft 2H to absorb the shock. Furthermore, in the case of an offset collision, the first impact absorbing portion 15H is bent at the plurality of grooves 3H, and the lower shaft 1H enters the gaps of the peripheral parts, whereby the impact is absorbed.

Therefore, the collapsing stroke S of the upper shaft 2H can be adjusted in view of the behavior of the vehicle body in various collisions. For this reason, the transmission of the impact can be suitably mitigated by the intermediate shaft.

Fifth Embodiment
FIG. 45 is a perspective view of the steering device of the fifth embodiment. FIG. 46 is a perspective view of the intermediate shaft of the fifth embodiment. FIG. 47 is a cross-sectional view of the intermediate shaft of the fifth embodiment. FIG. 48 is an enlarged cross-sectional view of the first impact absorbing portion and the first fitting portion of the first shaft. FIG. 49 is an enlarged cross-sectional view of the periphery of the groove of the first impact absorbing portion. FIG. 50 is an enlarged sectional view of a second impact absorbing portion of the first shaft. 51 is a cross-sectional view taken along line II in FIG. 52 is a cross-sectional view taken along line JJ in FIG. In addition, the same code | symbol is attached | subjected to the same component as what was demonstrated in embodiment mentioned above, and the overlapping description is abbreviate | omitted.

As shown in FIG. 46, the intermediate shaft 85I includes a first shaft 1I and a second shaft 2I.

The first shaft 1I is a substantially cylindrical solid member. For example, the first shaft 1I is formed of S35C which is carbon steel for machine structure (SC material). As shown in FIG. 47, the first shaft 1I includes a base 11I, a second impact absorbing portion 12I, a base 13I, a first impact absorbing portion 15I, and a first fitting portion 17I.

The base 11I is fixed to the first universal joint 84. The diameter of the base 11I is constant. The second shock absorber 12I is located in front of the base 11I. The second impact absorbing portion 12I is located rearward of the center of the first shaft 1I in the axial direction of the first shaft 1I. The base 13I is located in front of the second shock absorber 12I. The diameter of the base 13I is constant and equal to the diameter of the base 11I. The first shock absorber 15I is located in front of the base 13I. The first impact absorbing portion 15I is located at the center of the first shaft 1I in the axial direction of the first shaft 1I. The first fitting portion 17I is located at the front end of the first shaft 1I. The first fitting portion 17I includes serrations 17aI on the outer peripheral surface. Further, as shown in FIG. 47, the first fitting portion 17I has a recess 170I on the end face on the front side. The serrations 17aI may be splines.

In the following description, the axial direction of the first shaft 1I is simply described as the axial direction, and the direction orthogonal to the axial direction is described as the radial direction. 47 to 50 are cross sections obtained by cutting the first shaft 1I in a plane orthogonal to the radial direction.

As shown in FIG. 48, the first impact absorbing portion 15I includes a plurality of grooves 3I and a plurality of convex portions 4I. The grooves 3I are annular. The grooves 3I are formed by cutting, for example. The plurality of grooves 3I are arranged at equal intervals in the axial direction. The protrusion 4I is located between the two grooves 3I. The diameter D1I of the first impact absorbing portion 15I at the position corresponding to the convex portion 4I is equal to the diameters of the base 11I and the base 13I. Further, the diameter D1I is smaller than the minimum diameter D4I of the first fitting portion 17I. The minimum diameter D4I is the diameter of the first fitting portion 17I at a position corresponding to the valley of the serration 17aI. The diameter D1I may not necessarily be equal to the diameter of the base 11I. The diameter D1I should be at least larger than the diameter D2I of the first impact absorbing portion 15I at a position corresponding to the bottom of the groove 3I and smaller than the minimum diameter D4I of the first fitting portion 17I.

As shown in FIG. 49, the first impact absorbing portion 15I, as the surface facing the groove 3I, includes the first side surface 31I, the second side surface 33I, the bottom surface 35I, the first connection surface 36I, and the second connection surface. And 37I. The first side surface 31I and the second side surface 33I are perpendicular to the axial direction. That is, the second side surface 33I is parallel to the first side surface 31I. The bottom surface 35I is located between the first side surface 31I and the second side surface 33I. The first side surface 31I is located rearward with respect to the bottom surface 35I, and the second side surface 33I is located forward with respect to the bottom surface 35I. The bottom surface 35I is a curved surface. The first connection surface 36I is a curved surface connecting the first side surface 31I and the bottom surface 35I. The second connection surface 37I is a curved surface connecting the second side surface 33I and the bottom surface 35I.

The maximum width WI of the groove 3I is preferably 1 mm or more and 3 mm or less. The maximum width WI of the groove 3I is set so that the first impact absorbing portion 15I does not break when the first impact absorbing portion 15I is bent. The maximum width WI of the groove 3I is set such that, when the first impact absorbing portion 15I is bent, adjacent convex portions 4I are in contact before the first impact absorbing portion 15I breaks. In the cross section shown in FIG. 49, the first connection surface 36I and the second connection surface 37I draw the same arc (hereinafter, referred to as a first arc). The radius of curvature C1I of the first arc is preferably 0.2 mm or more and 1.0 mm or less. For example, the curvature radius C1I in the fifth embodiment is 0.3 mm.

The first shock absorber 15I is designed to transmit a torque of, for example, 300 Nm. When the first shaft 1I is formed of S35C, the diameter D2I of the first impact absorbing portion 15I at a position corresponding to the bottom of the groove 3I is approximately 14 mm or more and 16 mm or less. The diameter D2I is determined by the depth HI of the groove 3I shown in FIG.

As shown in FIG. 50, the second impact absorbing portion 12I includes a small diameter portion 125I, a first connection portion 121I, and a second connection portion 129I. The small diameter portion 125I is cylindrical. The diameter D3 of the small diameter portion 125I is smaller than the diameter D2I shown in FIG. The axial length L of the small diameter portion 125I is larger than the maximum width WI of the groove 3I. The first connection portion 121I connects the base 11I and the small diameter portion 125I. The second connection portion 129I connects the base 13I and the small diameter portion 125I. In the cross section shown in FIG. 50, the surfaces of the first connection portion 121I and the second connection portion 129I draw the same arc (hereinafter, referred to as a second arc). The curvature radius C2I of the second arc is larger than the curvature radius C1I of the first arc. The curvature radius C2I is preferably 5 mm or more. For example, the curvature radius C2I is 8 mm.

The second impact absorbing portion 12I is designed to be deformed by, for example, a torque of about 150 Nm or more and 250 Nm or less. When the intermediate shaft 85I is formed of S35C, the diameter D3 is about 13 mm or more and 15.5 mm or less. For example, in the fifth embodiment, the diameter D3 is 13 mm.

As shown in FIG. 47, the second shaft 2I is cylindrical. For example, the second shaft 2I is formed of carbon steel pipe for machine structure (STKM material). The second shaft 2I includes a second fitting portion 21I, a large diameter portion 23I, and a base 25I.

The second fitting portion 21I is disposed at the rear end of the second shaft 2I. The first fitting portion 17I is inserted into the second fitting portion 21I. The second fitting portion 21I includes serrations 21aI on the inner circumferential surface. The serration 21aI meshes with the serration 17aI. The serrations 21aI may be splines.

As shown in FIG. 51, the outer shape of the first fitting portion 17I draws a circle in a cross section orthogonal to the axial direction. In the cross section shown in FIG. 51, the outer shape of the second fitting portion 21I draws an ellipse. As shown in FIG. 52, the outer shape of the first fitting portion 17I draws an ellipse in a cross section different from that of FIG. 51 among the cross sections orthogonal to the axial direction. In the cross section shown in FIG. 52, the outer shape of the second fitting portion 21I draws a circle. The shapes of the second fitting portion 21I of FIG. 51 and the first fitting portion 17I of FIG. 52 are exaggerated for the sake of description, and are different from the actual shapes. In fact, all the teeth of serration 21aI are located between the two teeth of serration 17aI respectively. That is, the teeth of serration 21aI located on the left side and the right side of FIG. 51 are not in contact with the teeth of serration 17aI, but are located between the two teeth of serration 17aI. The teeth of serration 21aI located on the upper and lower sides of FIG. 52 are not in contact with the teeth of serration 17aI, but are located between the two teeth of serration 17aI.

When assembling the intermediate shaft 85I, a part of the first fitting portion 17I is inserted into the second fitting portion 21I. Then, the first fitting portion 17I and the second fitting portion 21I are pressed from two directions at the position corresponding to the recess 170I. Thereafter, the first fitting portion 17I is further pushed into the second fitting portion 21I. Thereby, cross-sectional shapes shown in FIGS. 51 and 52 are formed. In addition, such a connection method of the 1st fitting part 17I and the 2nd fitting part 21I may be called an elliptical fitting.

The movement of the second fitting portion 21I with respect to the first fitting portion 17I is restricted by the friction generated in the contact portion of the first fitting portion 17I with the second fitting portion 21I. That is, in normal use (when no collision occurs), the second fitting portion 21I does not move with respect to the first fitting portion 17I. On the other hand, when a predetermined load in the axial direction is applied to the second shaft 2I at the time of a collision, the second fitting portion 21I moves relative to the first fitting portion 17I. The predetermined load is, for example, about 1 kN or more and 3 kN or less. That is, the second shaft 2I is connected to the first shaft 1I so that it can be separated from the first shaft 1I at the time of a collision. An impact is absorbed by the friction between the second fitting portion 21I and the first fitting portion 17I.

The large diameter portion 23I is disposed in front of the second fitting portion 21I. The outer diameter of the large diameter portion 23I is constant. The outer diameter of the large diameter portion 23I is larger than the outer diameter of the second fitting portion 21I.

The base 25I is disposed at the front end of the second shaft 2I. The base 25I is fixed to the second universal joint 86. The outer diameter of the base 25I is constant. The outer diameter of the base 25I is equal to the outer diameter of the second fitting portion 21I.

FIG. 53 is a perspective view of the intermediate shaft after the first shaft has entered the second shaft. FIG. 54 is a perspective view of the intermediate shaft after the first shaft is bent.

When the vehicle collides, a load is applied to the steering gear 88. The load applied to the steering gear 88 is transmitted to the second shaft 2I via the second universal joint 86. If all of the front of the vehicle hit the collision object (in the case of a full wrap collision), the second shaft 2I is often subjected to an axial load. In the case of a full wrap collision, as shown in FIG. 53, the impact is absorbed by moving the second shaft 2I relative to the first shaft 1I. As a result, the shock transmitted to the steering wheel 81 is reduced.

On the other hand, when a part of the front of the vehicle collides with the collision target (in the case of an offset collision), a non-axial load is often applied to the second shaft 2I. For this reason, the second shaft 2I can not move straight with respect to the first shaft 1I. In the case of an offset collision, bending stress occurs in the intermediate shaft 85I. At this time, stress concentration occurs in the first connection surface 36I and the second connection surface 37I, whereby the first impact absorbing portion 15I is bent as shown in FIG. 54 starting from the first connection surface 36I and the second connection surface 37I. . One side of the groove 3I in the radial direction expands, and the other side of the groove 3I in the radial direction contracts. On the side where the groove 3I is contracted, the convex portion 4I is in contact with the adjacent convex portion 4I. The bent intermediate shaft 85I enters the clearance of the peripheral parts of the intermediate shaft 85I. By the bending of the first impact absorbing portion 15I, the impact due to the collision is absorbed. As a result, the shock transmitted to the steering wheel 81 is reduced.

Since the first impact absorbing portion 15I includes the plurality of grooves 3I, when bending stress acts on the intermediate shaft 85I, stress concentration occurs in the plurality of portions of the first impact absorbing portion 15I. Therefore, the range of the deformed portion of the first impact absorbing portion 15I is likely to be large, so that the impact absorbing ability of the intermediate shaft 85I is improved.

The intermediate shaft 85I may generate bending stress due to the primary collision, and may receive a large torque (twisting force) when the vehicle runs on a curb or the like. Therefore, the intermediate shaft 85I is required to be able to suppress damage when receiving a large torque and to absorb an impact at the time of a primary collision.

In the intermediate shaft 85I of the fifth embodiment, the diameter D3 is smaller than the diameter D2I. For this reason, the second impact absorbing portion 12I is deformed (twisted) when the vehicle rides on a curb or the like. The energy input to the intermediate shaft 85I is absorbed by the deformation of the second impact absorbing portion 12I. Since energy is absorbed by the second impact absorbing portion 12I, deformation of the first impact absorbing portion 15I is suppressed.

On the other hand, in the intermediate shaft 85I of the fifth embodiment, the curvature radius C2I is larger than the curvature radius C1I. Therefore, when bending stress is generated in the intermediate shaft 85I at the time of the primary collision, the first impact absorbing portion 15I, not the second impact absorbing portion 12I, is deformed (bent).

In addition, the connection method of the 1st fitting part 17I and the 2nd fitting part 21I may be a connection method using a resin coat slider, or a connection method using a rolling element. The connection method using the resin-coated slider is a method of fitting the first fitting portion 17I having a lubricating film to the second fitting portion 21I. The lubricating coating is formed, for example, by applying a grease on a coating of a synthetic resin on the outer peripheral surface of the first fitting portion 17I. As a result, the wear on the contact portion between the first fitting portion 17I and the second fitting portion 21I is reduced and the frictional resistance is reduced. In addition, a lubricating film may be provided in the 2nd fitting part 21I, and may be provided in both the 1st fitting part 17I and the 2nd fitting part 21I. Moreover, the connection method using a rolling element is a method of connecting the 1st fitting part 17I and the 2nd fitting part 21I via a rolling element. Examples of rolling elements include balls or rollers. Balls and rollers may be combined as rolling elements. As a result, the wear on the contact portion between the first fitting portion 17I and the second fitting portion 21I is reduced and the frictional resistance is reduced.

As described above, the steering device 80I includes the first universal joint 84, the second universal joint 86 disposed forward of the first universal joint 84, the first universal joint 84, and the second universal joint 86. And an intermediate shaft 85I connecting the two. The intermediate shaft 85I includes a first shaft 1I which is a solid member, and a cylindrical second shaft 2I releasably connected to the first shaft 1I. The first shaft 1I includes a first impact absorbing portion 15I having a groove 3I on the outer peripheral surface.

As a result, no mold is required when forming the first impact absorbing portion 15I, so the formation of the first impact absorbing portion 15I is facilitated. Also, the deformation characteristics of the first impact absorbing portion 15I change according to the shape of the groove 3I of the first impact absorbing portion 15I. Since it is easy to change the shape of the groove 3I, it is easy to adjust the deformation characteristics of the first impact absorbing portion 15I. Therefore, the steering device 80I can absorb an impact by the intermediate shaft 85I which can be easily manufactured and can easily change its deformation characteristics.

Furthermore, the second shaft 2I moves relative to the first shaft 1I at the time of the primary collision. The steering device 80I can absorb an impact by the friction generated between the first shaft 1I and the second shaft 2I.

In addition, the first shaft 1I includes a first fitting portion 17I having serrations 17aI on the outer peripheral surface. The second shaft 2I includes a second fitting portion 21I having serrations 21aI on its inner circumferential surface. The first fitting portion 17I fits into the second fitting portion 21I. The maximum outer diameter (diameter D1I) of the first impact absorbing portion 15I is smaller than the minimum diameter D4I of the first fitting portion 17I.

As a result, when the second shaft 2I moves relative to the first shaft 1I, interference between the first impact absorbing portion 15I and the serration 21aI of the second fitting portion 21I becomes difficult. Therefore, the steering device 80I can suppress the variation in the shock absorbing capability of the intermediate shaft 85I.

First Modification of Fifth Embodiment
FIG. 55 is an enlarged cross-sectional view of a peripheral portion of a groove of a first impact absorbing portion in a first modified example of the fifth embodiment. In addition, the same code | symbol is attached | subjected to the same component as what was demonstrated in embodiment mentioned above, and the overlapping description is abbreviate | omitted.

As shown in FIG. 55, in the first modification of the fifth embodiment, the covering material 5I is provided in the first impact absorbing portion 15J. The covering material 5I covers the surfaces (the first side surface 31I, the second side surface 33I, the bottom surface 35I, the first connection surface 36I and the second connection surface 37I) facing the groove 3I of the first impact absorbing portion 15J. That is, the covering material 5I covers the inner peripheral surface of the groove 3I. In addition, the covering material 5I covers the main surface 150I which is the surface outside the groove 3I of the first impact absorbing portion 15J. That is, in the first modification of the fifth embodiment, the covering material 5I covers the entire surface of the first impact absorbing portion 15J. The covering material 5I is an antirust film. The covering material 5I contains, for example, zinc or nickel. In other words, zinc plating, nickel plating, or the like is applied to the surface of the first impact absorbing portion 15J.

In addition, the covering material 5I does not necessarily need to cover the whole surface of the 1st impact-absorbing part 15J. The covering material 5I should just cover at least one part of the surface which faces the groove 3I of the 1st impact-absorbing part 15J. The covering material 5I preferably covers at least the bottom surface 35I, the first connection surface 36I, and the second connection surface 37I. Also, the covering material 5I may be, for example, a grease. In this case, the viscosity of the grease is preferably high.

As described above, the steering device 80I according to the first modified example of the fifth embodiment includes the covering material 5I covering at least a part of the surface of the first impact absorbing portion 15J facing the groove 3I. The covering material 5I is an antirust film.

The first shock absorber 15J is designed to transmit a predetermined torque (for example, 300 Nm). In the first impact absorbing portion 15J having the groove 3I, the strength against torque of the portion corresponding to the groove 3I is low. Although the first shock absorber 15J is designed in consideration of a sufficient safety factor, there is a possibility that the first shock absorber 15J can not withstand a predetermined torque if rust occurs in the first shock absorber 15J. is there. On the other hand, in the first impact absorbing portion 15J, the covering material 5I suppresses the occurrence of rust on the surface facing the groove 3I. The reduction in strength of the portion of the first impact absorbing portion 15J corresponding to the groove 3I is suppressed. The first modification of the fifth embodiment is particularly effective when disposed at a place where water such as rain may be applied.

In addition, the covering material 5I covers the main surface 150I which is the surface outside the groove 3I of the first impact absorbing portion 15J.

As described above, when a predetermined load in the axial direction is applied to the intermediate shaft 85I, the first shaft 1I and the second shaft 2I move relatively. If a bending moment is also applied to the intermediate shaft 85I, the second shaft 2I may be caught by the first impact absorbing portion 15J. In contrast, the friction between the second shaft 2I and the first impact absorbing portion 15J is reduced by covering the main surface 150I with the covering material 5I. Therefore, even if the second shaft 2I contacts the first impact absorbing portion 15J, the second shaft 2I is unlikely to be caught by the first impact absorbing portion 15J. For this reason, the movement of the second shaft 2I becomes smooth.

Second Modification of Fifth Embodiment
FIG. 56 is an enlarged cross-sectional view of a first impact absorbing portion in a second modified example of the fifth embodiment. In addition, the same code | symbol is attached | subjected to the same component as what was demonstrated in embodiment mentioned above, and the overlapping description is abbreviate | omitted.

As shown in FIG. 56, in the second modification of the fifth embodiment, the filler 6I is provided in the groove 3I. For example, the filler 6I is disposed in all of the plurality of grooves 3I. For example, the depth of the filler 6I is equal to the depth HI of the groove 3I (see FIG. 49). The filler 6I is preferably a resin or rubber. Furthermore, the filler 6I is preferably a rubber which is a closed cell. The Young's modulus of the filler 6I is smaller than the Young's modulus of the first impact absorbing portion 15K. When a bending moment is applied to the first impact absorbing portion 15K, the filler 6I is easily deformed.

The depth of the filler 6I may be smaller than the depth HI (see FIG. 49) of the groove 3I. That is, the volume of the filler 6I embedded in one groove 3I may be smaller than the volume of one groove 3I. The filler 6I preferably covers the bottom surface 35I, the first connection surface 36I and the second connection surface 37I. In addition, both the filler 6I and the covering 5I described in the first modification of the fifth embodiment may be provided in the groove 3I. That is, the covering material 5I may cover the first impact absorbing portion 15K, and the filling material 6I may cover the covering material 5I. The filler 6I may be, for example, grease. In this case, the viscosity of the grease is preferably high.

As described above, the steering device 80I of the second modified example of the fifth embodiment includes the filler 6I disposed in the groove 3I.

In the first impact absorbing portion 15K of the second modified example of the fifth embodiment, the filling material 6I makes it difficult for water to enter the groove 3I. For this reason, the generation of rust on the surface of the first impact absorbing portion 15K facing the groove 3I is suppressed. The reduction in strength of the portion of the first impact absorbing portion 15K corresponding to the groove 3I is suppressed. The second modification of the fifth embodiment is particularly effective in the case of being disposed at a place where water such as rain may be applied.

The filler 6I is a resin. This makes it difficult for the filler 6I to inhibit the deformation of the first impact absorbing portion 15K.

The filler 6I is rubber. This makes it difficult for the filler 6I to inhibit the deformation of the first impact absorbing portion 15K.

The filler 6I is a closed cell. Thereby, the increase in the weight of the first shock absorber 15K is suppressed.

Further, the volume of the filler 6I is the same as the volume of the groove 3I.

As a result, the groove 3I is filled with the filler 6I, so the outer peripheral surface of the first impact absorbing portion 15K becomes smooth. The friction between the second shaft 2I and the first shock absorber 15K is reduced. Therefore, even when the second shaft 2I contacts the first impact absorbing portion 15K, the second shaft 2I is unlikely to be caught by the first impact absorbing portion 15K. For this reason, the movement of the second shaft 2I becomes smooth.

(Third Modification of Fifth Embodiment)
FIG. 57 is a cross-sectional view of the intermediate shaft of the third modified example of the fifth embodiment. In addition, the same code | symbol is attached | subjected to the same component as what was demonstrated in embodiment mentioned above, and the overlapping description is abbreviate | omitted.

As shown in FIG. 57, in the third modification of the fifth embodiment, the first shaft 1I is located in front of the second shaft 2I. The first shaft 1I includes a stopper 14I and a base 19I. The stopper 14I protrudes radially from the outer peripheral surface of the base 13I. The stopper 14I is integrally formed with the base 13I. The stopper 14I overlaps the end face of the second fitting portion 21I when viewed from the axial direction. The stopper 14I is located behind the first impact absorbing portion 15I. For this reason, the distance from the end face of the second fitting portion 21I to the stopper 14I is smaller than the distance from the end face of the second fitting portion 21I to the first impact absorbing portion 15I. The base 19I is located in front of the first shock absorber 15I and connected to the second universal joint 86. The diameter of the base 19I is constant and equal to the diameter of the base 11I.

When the first shaft 1I and the second shaft 2I move relative to each other, the stopper 14I contacts the end face of the second fitting portion 21I. The stopper 14I regulates the relative movement amount of the first shaft 1I and the second shaft 2I. Since the stopper 14I is located at the rear of the first shock absorbing portion 15I, the stopper 14I contacts the second fitting portion 21I before the first shock absorbing portion 15I enters the second shaft 2I. Thus, the first shaft 1I can bend after being moved relative to the second shaft 2I.

The stopper 14I may be provided on the second shaft 2I. For example, the stopper 14I may be provided on the inner circumferential surface of the second shaft 2I and may overlap the first fitting portion 17I when viewed in the axial direction. In such a case, the distance from the end face of the first fitting portion 17I to the stopper 14I is preferably smaller than the distance from the end face of the second fitting portion 21I to the first impact absorbing portion 15I. Thus, the first fitting portion 17I contacts the stopper 14I before the first impact absorbing portion 15I enters the second shaft 2I. Thus, the first shaft 1I can bend after being moved relative to the second shaft 2I.

The stopper 14I may be connected to the base 13I by welding or the like. A C-type retaining ring or an E-type retaining ring may be used as the stopper 14I.

As described above, the intermediate shaft 85L includes the stopper 14I that regulates the relative movement amount of the first shaft 1I and the second shaft 2I.

This makes it possible to adjust the relative movement amount of the first shaft 1I and the second shaft 2I, so that it is possible to prevent an excessive load from being applied to the second shaft 2I.

Sixth Embodiment
FIG. 58 is a perspective view of the steering device of the sixth embodiment. FIG. 59 is a side view of the intermediate shaft of the sixth embodiment. FIG. 60 is a cross-sectional view of the intermediate shaft of the sixth embodiment. FIG. 61 is an enlarged view of the first shock absorber in FIG. 60. Figure 62 is an enlarged view of the groove of Figure 60; FIG. 63 is an enlarged view of a second shock absorber shown in FIG. 60.

In the following description, the axial direction of the intermediate shaft 85M is simply described as the axial direction, and the direction orthogonal to the axial direction is described as the radial direction. 60 to 63 are cross sections obtained by cutting the intermediate shaft 85M in a plane orthogonal to the radial direction.

The intermediate shaft 85M is a substantially cylindrical hollow member. For example, the intermediate shaft 85M is formed of carbon steel pipe for machine structure (STKM material). The intermediate shaft 85M is preferably formed of STKM 12B (JIS G 3445). The tensile strength of STKM 12B is 340 MPa or more, and the elongation in the direction perpendicular to the tube axis is 20% or more. For this reason, the intermediate shaft 85M is easy to twist and does not easily buckle. The intermediate shaft 85M may be formed of STKM 13A or STKM 15A (JIS G 3445) or the like. As shown in FIG. 60, the intermediate shaft 85M is provided with a hole 10M. The inner diameter D10M (diameter of the hole 10M) of the intermediate shaft 85M is constant over the entire axial length. The inner diameter D10M is preferably 9 mm or more and 15 mm or less. For example, the inner diameter D10M in the sixth embodiment is 9.4 mm. The tolerance of the inner diameter D10M is preferably within ± 0.1 mm.

As shown in FIGS. 59 and 60, the intermediate shaft 85M includes a base 11M, a first shock absorber 15M, a base 16M, a second shock absorber 17M, and a base 19M.

The base 11M is connected to the first universal joint 84. The base 11M is cylindrical, and the outer diameter of the base 11M is constant. The base 11M has an outer diameter D1M. The outer diameter D1M is preferably 15 mm or more and 18 mm or less. For example, the outer diameter D1M in the sixth embodiment is 16.8 mm. The tolerance of the outer diameter D1M is preferably within +0.2 mm. The thickness T1M of the base 11M is 3.7 mm. The first shock absorber 15M is located in front of the base 11M. The first impact absorbing portion 15M is located at the center of the intermediate shaft 85M in the axial direction of the intermediate shaft 85M. The base 16M is located in front of the first shock absorber 15M. The outer diameter of the base 16M is constant and equal to the outer diameter D1M. The second shock absorber 17M is located in front of the base 16M. The second shock absorber 17M is located forward of the center of the intermediate shaft 85M. The base 19M is connected to the second universal joint 86. The outer diameter of the base 19M is constant and equal to the outer diameter D1M.

As shown in FIG. 61, the first impact absorbing portion 15M includes a plurality of grooves 3M and a plurality of convex portions 4M. The groove 3M is annular. The groove 3M is formed, for example, by cutting the outer peripheral surface of the carbon steel pipe for machine structure. The plurality of grooves 3M are arranged at equal intervals in the axial direction. The protrusion 4M is located between the two grooves 3M. The outer diameter of the first impact absorbing portion 15M at the position corresponding to the convex portion 4M is equal to the outer diameter D1M.

As shown in FIG. 61, the first impact absorbing portion 15M has a first side 31M, a second side 33M, a bottom 35M, a first connection surface 36M, and a second connection surface as surfaces facing the groove 3M. And 37M. The first side surface 31M and the second side surface 33M are perpendicular to the axial direction. That is, the second side surface 33M is parallel to the first side surface 31M. The bottom surface 35M is located between the first side 31M and the second side 33M. The first side surface 31M is located rearward with respect to the bottom surface 35M, and the second side surface 33M is located forward with respect to the bottom surface 35M. The bottom surface 35M is a curved surface. The first connection surface 36M is a curved surface connecting the first side surface 31M and the bottom surface 35M. The second connection surface 37M is a curved surface connecting the second side surface 33M and the bottom surface 35M.

The first shock absorber 15M is designed to transmit, for example, a torque of 300 Nm. The torque that can be transmitted by the first shock absorber 15M is determined by the outer diameter D2M of the first shock absorber 15M at the position corresponding to the groove 3M (determined by the depth HM of the groove 3M shown in FIG. 62). The outer diameter D2M is preferably 15.5 mm or more and 16.5 mm or less. For example, the outer diameter D2M in the sixth embodiment is 16 mm.

The maximum width WM of the groove 3M is preferably 1 mm or more and 3 mm or less. The maximum width WM of the groove 3M is set so that the first shock absorber 15M does not break when the first shock absorber 15M is bent. The maximum width WM of the groove 3M is set such that, when the first impact absorbing portion 15M is bent, adjacent convex portions 4M are in contact before the first impact absorbing portion 15M breaks. In the cross section shown in FIG. 62, the first connection surface 36M and the second connection surface 37M draw the same arc (hereinafter referred to as a first arc). The curvature radius C 1 M of the first arc is preferably 0.2 mm or more and 1.0 mm or less (the curvature of the first arc is preferably 1.0 mm −1 or more and 5.0 mm 1 or less). For example, the radius of curvature C1M in the sixth embodiment is 0.3 mm (the curvature of the first arc is 10/3 mm −1).

As shown in FIG. 63, the second impact absorbing portion 17M includes a small diameter portion 175M, a first connection portion 171M, and a second connection portion 179M. The small diameter portion 175M, the first connection portion 171M and the second connection portion 179M are formed, for example, by cutting the outer peripheral surface of the carbon steel pipe for machine structure. The arithmetic mean roughness (Ra) of the small diameter portion 175M, the first connection portion 171M and the second connection portion 179M is preferably 6.3 μm or less. For example, the arithmetic mean roughness (Ra) in the sixth embodiment is 3.2 μm. As a result, when the small diameter portion 175M is twisted, shearing is less likely to occur in the small diameter portion 175M.

The small diameter portion 175M is cylindrical, and the outer diameter of the small diameter portion 175M is constant. The small diameter portion 175M has an outer diameter D3M. The outer diameter D3M is smaller than the outer diameter D1M. The second impact absorbing portion 17M is designed to be deformed by a torque of, for example, 150 Nm or more and 250 Nm or less. Therefore, the outer diameter D3M is preferably 14 mm or more and 16 mm or less. For example, in the sixth embodiment, the outer diameter D3M is 15 mm. The tolerance of the outer diameter D3M is preferably within ± 0.05 mm. The thickness T3M of the small diameter portion 175M shown in FIG. 7 is 2.8 mm. The thickness T3M is preferably 10% or more and 20% or less of the outer diameter D3M. That is, in the sixth embodiment, the thickness T3M is preferably 1.5 mm or more and 3.0 mm or less. Thereby, the buckling of the small diameter portion 175M is suppressed and the small diameter portion 175M is easily twisted. The axial length LM of the small diameter portion 175M is larger than the maximum width WM of the groove 3M. The length LM is preferably 10 mm or more and 50 mm or less. For example, the length LM in the sixth embodiment is 15 mm. As the length LM increases, the small diameter portion 175M is more easily twisted. If the length LM is larger, the intermediate shaft 85M may be formed of a material whose elongation in the direction perpendicular to the tube axis is smaller than STKM 12B. On the other hand, the smaller the length LM, the easier the formation of the small diameter portion 175M.

The first connection portion 171M connects the base 16M and the small diameter portion 175M. The outer diameter of the first connection portion 171M decreases toward the small diameter portion 175M. The second connection portion 179M connects the base 19M and the small diameter portion 175M. The outer diameter of the second connection portion 179M decreases toward the small diameter portion 175M. In the cross section shown in FIG. 62, the surfaces of the first connection portion 171M and the second connection portion 179M draw the same arc (hereinafter, referred to as a second arc). The curvature radius C2M of the second arc is larger than the curvature radius C1M of the first arc (the curvature of the second arc is smaller than the curvature of the first arc). The radius of curvature C2M is preferably 2 mm or more (the curvature of the second arc is preferably 0.5 mm-1 or less). For example, the radius of curvature C2M is 8 mm (the curvature of the second arc is 0.125 mm-1).

FIG. 64 is a side view of the intermediate shaft after bending. A load is applied to the steering gear 88 at the time of a primary collision of the vehicle. The load applied to the steering gear 88 generates bending stress on the intermediate shaft 85M. In addition, bending stress due to a primary collision may occur in the intermediate shaft 85M, and a large torque (torsion force) may be input when the vehicle runs on a curb or the like. Therefore, the intermediate shaft 85M is required to be able to suppress damage when receiving a large torque and to absorb an impact at the time of a primary collision.

In the intermediate shaft 85M, the first impact absorbing portion 15M and the second impact absorbing portion 17M are more easily deformed than the other portions. As described above, the radius of curvature C2M shown in FIG. 63 is larger than the radius of curvature C1M shown in FIG. Therefore, when bending stress occurs in the intermediate shaft 85M, the first impact absorbing portion 15M bends from the first connection surface 36M and the second connection surface 37M where stress concentration easily occurs. One side in the radial direction of the groove 3M expands, and the other side in the radial direction of the groove 3M contracts. On the side where the groove 3M is contracted, the convex portion 4M is in contact with the adjacent convex portion 4M. The bent intermediate shaft 85M enters the clearance of the peripheral parts of the intermediate shaft 85M. By bending the first impact absorbing portion 15M, the impact due to the collision is absorbed. As a result, the shock transmitted to the steering wheel 81 is reduced.

On the other hand, the outer diameter of the intermediate shaft 85M is minimized at the small diameter portion 175M. Therefore, when a large torque is input to the intermediate shaft 85M, the second impact absorbing portion 17M is deformed (twisted). The energy input to the intermediate shaft 85M is absorbed by the deformation of the second impact absorbing portion 17M. Since energy is absorbed by the second impact absorbing portion 17M, deformation of the first impact absorbing portion 15M is suppressed. For this reason, in the first impact absorbing portion 15M, the designed deformation characteristic to the bending stress is maintained. The energy absorbed by the deformation (twisting) of the second impact absorbing portion 17M is required to be, for example, about 300 J or more and about 500 J.

In addition, the intermediate shaft 85M may not necessarily be formed of carbon steel pipe for machine structure, and may be formed of other materials. However, in order to facilitate manufacture, the intermediate shaft 85M is preferably formed of a cylindrical material.

The groove 3M of the first impact absorbing portion 15M may not necessarily have the above-described shape. For example, the first connection surface 36M and the second connection surface 37M may be connected without the bottom surface 35M. That is, in a cross section obtained by cutting the intermediate shaft 85M in a plane perpendicular to the radial direction, the surface of the first shock absorber 15M at a position corresponding to the bottom of the groove 3M may draw a semicircle. Also, the first connection surface 36M and the second connection surface 37M may not be present. That is, the first side surface 31M and the second side surface 33M may be directly connected to the bottom surface 35M.

The number of grooves 3M provided in the first impact absorbing portion 15M may not necessarily be as shown in the drawing. The first shock absorber 15M may have at least one groove 3M. The outer diameter of the first impact absorbing portion 15M at the position corresponding to the convex portion 4M may not necessarily be equal to the outer diameter D1M, and may be at least larger than the outer diameter D2M.

The intermediate shaft 85M may have a plurality of members. For example, the intermediate shaft 85M may include a first shaft and a second shaft coupled to the first shaft. In such a case, at least one of the first shaft and the second shaft may have the above-described configuration of the intermediate shaft 85M. In other words, in the sixth embodiment, the intermediate shaft 85M is the first shaft.

As described above, the steering device 80M includes the first universal joint 84, the second universal joint 86 disposed on the front side of the first universal joint 84, the first universal joint 84, and the second universal joint 86. And an intermediate shaft 85M positioned therebetween. The intermediate shaft 85M is a hollow member whose inner diameter is constant over the entire axial length. The intermediate shaft 85M includes a first impact absorbing portion 15M having a groove 3M on the outer circumferential surface.

Thereby, since the first impact absorbing portion 15M can be formed by cutting or the like, no mold is required when forming the first impact absorbing portion 15M. Therefore, the formation of the first impact absorbing portion 15M is facilitated. Also, the deformation characteristics of the first impact absorbing portion 15M change according to the shape of the groove 3M of the first impact absorbing portion 15M. Since it is easy to change the shape of the groove 3M by changing the cutting range, it is easy to adjust the deformation characteristics of the first impact absorbing portion 15M. Accordingly, the steering device 80M can absorb an impact by the intermediate shaft 85M which can be easily manufactured and can easily change its deformation characteristics.

The intermediate shaft 85M also includes a second impact absorbing portion 17M having an outer diameter D3M smaller than the outer diameter D2M of the first impact absorbing portion 15M at a position corresponding to the bottom of the groove 3M.

Thus, when a large torque acts on the intermediate shaft 85M, energy is absorbed by deformation of the second impact absorbing portion 17M. On the other hand, the deformation of the first shock absorber 15M is suppressed. For this reason, the designed deformation characteristic of the first impact absorbing portion 15M is maintained. As a result, when a collision of a vehicle occurs, the intermediate shaft 85M can exhibit a predetermined shock absorbing capability.

Further, in a cross section obtained by cutting the intermediate shaft 85M in a plane perpendicular to the radial direction, at least a part of the surface of the first impact absorbing portion 15M facing the groove 3M draws a first arc, and the second impact absorbing portion 17M At least a portion of the surface of the circle draws a second arc. The radius of curvature C2M of the second arc is larger than the radius of curvature C1M of the first arc.

As a result, when bending stress is generated in the intermediate shaft 85M, stress concentration is more likely to occur in the first impact absorbing portion 15M than in the second impact absorbing portion 17M. For this reason, the intermediate shaft 85M bends not from the second impact absorbing portion 17M but from the first impact absorbing portion 15M. Therefore, when a collision of a vehicle occurs, the intermediate shaft 85M can exhibit a predetermined shock absorbing capability.

The minimum thickness (thickness T3M) of the second impact absorbing portion 17M is 10% or more and 20% or less of the outer diameter D3M of the second impact absorbing portion 17M.

Thereby, the buckling of the second impact absorbing portion 17M is suppressed and the second impact absorbing portion 17M is easily twisted. As a result, the shock absorbing ability of the intermediate shaft 85M is improved.

First Modification of Sixth Embodiment
FIG. 65 is a perspective view of an intermediate shaft of a first modified example of the sixth embodiment. FIG. 66 is a cross-sectional view of the intermediate shaft of the first modified example of the sixth embodiment. FIG. 67 is an enlarged cross-sectional view of a first impact absorbing portion and a first fitting portion of a first shaft. FIG. 68 is a cross-sectional view taken along line KK in FIG. 69 is a cross-sectional view taken along line LL in FIG. The same components as those described in the first embodiment described above are denoted by the same reference numerals and redundant description will be omitted.

As shown in FIG. 65, the intermediate shaft 85N includes a first shaft 1M and a second shaft 2M.

As shown in FIG. 66, the first shaft 1M is a substantially cylindrical hollow member. The first shaft 1M is formed of carbon steel pipe for machine structure. The first shaft 1M includes a base 13M and a first fitting portion 18M.

The second shock absorber 17M is located in front of the base 11M. The second shock absorber 17M is located rearward of the center of the first shaft 1M in the axial direction. The base 13M is located in front of the second shock absorber 17M. The outer diameter of the base 13M is constant and equal to the outer diameter D1M. The first shock absorber 15M is located in front of the base 13M. The first impact absorbing portion 15M is located at the center of the first shaft 1M in the axial direction of the first shaft 1M. The first fitting portion 18M is located at the front end of the first shaft 1M. The first fitting portion 18M includes serrations 18aM on the outer peripheral surface. As shown in FIG. 67, the outer diameter D1M is smaller than the minimum outer diameter D4 of the first fitting portion 18M. The minimum outer diameter D4 is the outer diameter of the first fitting portion 18M at a position corresponding to the valley of the serration 18aM. Further, as shown in FIG. 66, the first fitting portion 18M has a recess 180M on the end face on the front side. The serrations 18aM may be splines.

In the manufacturing process of the first shaft 1M, after the first fitting portion 18M is formed, the second impact absorbing portion 17M is formed by cutting. Then, after the second impact absorbing portion 17M is formed, the resin coating is applied to the first shaft 1M. Thereafter, the shaving process is performed on the first shaft 1M. If cutting is performed after resin coating, cutting powder may be mixed into the resin coating. In such a case, when the first shaft 1M and the second shaft 2M move relative to each other, friction may increase and a stick-slip phenomenon (vibration due to repeated friction and sliding) may occur. On the other hand, in the manufacturing process of the first shaft 1M, since the cutting for forming the second impact absorbing portion 17M is performed before the resin coating, the mixing of the cutting powder into the resin coating is suppressed. . For this reason, the stick-slip phenomenon when the first shaft 1M and the second shaft 2M move relative to each other is suppressed.

As shown in FIG. 66, the second shaft 2M is cylindrical. For example, the second shaft 2M is formed of carbon steel pipe for machine structure. The second shaft 2M includes a second fitting portion 21M, a large diameter portion 23M, and a base 25M.

The second fitting portion 21M is disposed at the rear end of the second shaft 2M. The first fitting portion 18M is inserted into the second fitting portion 21M. The second fitting portion 21M includes serrations 21aM on the inner circumferential surface. The serration 21aM meshes with the serration 18aM. The serrations 21aM may be splines.

As shown in FIG. 68, the outer shape of the first fitting portion 18M draws a circle in a cross section perpendicular to the axial direction. In the cross section shown in FIG. 68, the outer shape of the second fitting portion 21M draws an ellipse. As shown in FIG. 69, of the cross sections perpendicular to the axial direction, the outer shape of the first fitting portion 18M draws an ellipse in a cross section different from FIG. In the cross section shown in FIG. 69, the outer shape of the second fitting portion 21M draws a circle. The shapes of the second fitting portion 21M of FIG. 68 and the first fitting portion 18M of FIG. 69 are exaggerated for the sake of description, and are different from the actual shape. In fact, all the teeth of serration 21aM are located between the two teeth of serration 18aM respectively. That is, the teeth of serration 21aM located on the left and right sides of FIG. 68 are not in contact with the teeth of serration 18aM, but are located between two teeth of serration 18aM. The upper and lower serration 21aM teeth of FIG. 69 are not in contact with the teeth of serration 18aM, but are located between the two teeth of serration 18aM.

When assembling the intermediate shaft 85N, a part of the first fitting portion 18M is inserted into the second fitting portion 21M. And the 1st fitting part 18M and the 2nd fitting part 21M are pressed from 2 directions in the position corresponding to the recessed part 180M. Thereafter, the first fitting portion 18M is further pushed into the second fitting portion 21M. Thereby, cross-sectional shapes shown in FIGS. 68 and 69 are formed. In addition, such a connection method of the 1st fitting part 18M and the 2nd fitting part 21M may be called an elliptical fitting.

The movement of the second fitting portion 21M with respect to the first fitting portion 18M is restricted by the friction generated in the contact portion of the first fitting portion 18M with the second fitting portion 21M. That is, during normal use (when no collision occurs), the second fitting portion 21M does not move with respect to the first fitting portion 18M. On the other hand, when a predetermined load in the axial direction is applied to the second shaft 2M at the time of a collision, the second fitting portion 21M moves relative to the first fitting portion 18M. The predetermined load is, for example, about 1 kN or more and 3 kN or less. That is, the second shaft 2M is connected to the first shaft 1M so that it can be separated from the first shaft 1M at the time of a collision. An impact is absorbed by the friction between the second fitting portion 21M and the first fitting portion 18M.

The large diameter portion 23M is disposed in front of the second fitting portion 21M. The outer diameter of the large diameter portion 23M is constant. The outer diameter of the large diameter portion 23M is larger than the outer diameter of the second fitting portion 21M.

The base 25M is disposed at the front end of the second shaft 2M. The base 25M is fixed to the second universal joint 86. The outer diameter of the base 25M is constant. The outer diameter of the base 25M is equal to the outer diameter of the second fitting portion 21M.

FIG. 70 is a perspective view of the intermediate shaft after the first shaft is in the second shaft. FIG. 71 is a perspective view of the intermediate shaft after the first shaft is bent. When the vehicle collides, a load is applied to the steering gear 88. The load applied to the steering gear 88 is transmitted to the second shaft 2M via the second universal joint 86. If all of the front of the vehicle hit the collision object (in the case of a full wrap collision), the second shaft 2M is often axially loaded. In the case of a full wrap collision, as shown in FIG. 70, the second shaft 2M moves relative to the first shaft 1M to absorb the shock. As a result, the shock transmitted to the steering wheel 81 is reduced.

On the other hand, when a part of the front of the vehicle collides with the collision target (in the case of an offset collision), a non-axial load is often applied to the second shaft 2M. For this reason, the second shaft 2M can not move straight with respect to the first shaft 1M. In the case of an offset collision, bending stress occurs in the intermediate shaft 85N. At this time, stress concentration occurs in the first connection surface 36M and the second connection surface 37M (see FIG. 62), so that the first impact is generated as shown in FIG. 71 starting from the first connection surface 36M and the second connection surface 37M. Absorbent part 15M bends. The bent intermediate shaft 85N enters the gap of the peripheral parts of the intermediate shaft 85N. By bending the first impact absorbing portion 15M, the impact due to the collision is absorbed. As a result, the shock transmitted to the steering wheel 81 is reduced.

In addition, the connection method of the 1st fitting part 18M and the 2nd fitting part 21M may be a connection method using a resin coat slider, or a connection method using a rolling element. The connection method using the resin-coated slider is a method of fitting the first fitting portion 18M having a lubricating film to the second fitting portion 21M. The lubricating coating is formed, for example, by applying a grease on a coating of a synthetic resin on the outer peripheral surface of the first fitting portion 18M. As a result, the wear of the contact portion between the first fitting portion 18M and the second fitting portion 21M is reduced and the frictional resistance is reduced. In addition, a lubricating film may be provided in the 2nd fitting part 21M, and may be provided in both the 1st fitting part 18M and the 2nd fitting part 21M. Moreover, the connection method using a rolling element is a method of connecting the 1st fitting part 18M and the 2nd fitting part 21M via a rolling element. Examples of rolling elements include balls or rollers. Balls and rollers may be combined as rolling elements. As a result, the wear of the contact portion between the first fitting portion 18M and the second fitting portion 21M is reduced and the frictional resistance is reduced.

The intermediate shaft 85N may be provided with a stopper for preventing the relative displacement of the first shaft 1M and the second shaft 2M. The stopper is, for example, a C-shaped resin ring, and is disposed around the second impact absorbing portion 17M.

As described above, the intermediate shaft 85N includes the cylindrical second shaft 2M releasably connected to the first shaft 1M.

Thereby, the second shaft 2M moves relative to the first shaft 1M at the time of the primary collision. The steering device 80M can absorb an impact by the friction generated between the first shaft 1M and the second shaft 2M.

In addition, the first shaft 1M includes a first fitting portion 18M having serrations 18aM on the outer peripheral surface. The second shaft 2M includes a second fitting portion 21M having serrations 21aM on the inner circumferential surface. The first fitting portion 18M fits into the second fitting portion 21M. The maximum outside diameter (outside diameter D1M) of the first impact absorbing portion 15M is smaller than the minimum outside diameter D4 of the first fitting portion 18M.

As a result, when the second shaft 2M moves relative to the first shaft 1M, the first impact absorbing portion 15M and the serrations 21aM of the second fitting portion 21M do not easily interfere with each other. Therefore, the steering device 80M can suppress the variation in the shock absorbing capability of the intermediate shaft 85N.

Second Modified Example of Sixth Embodiment
FIG. 72 is a cross-sectional view of the intermediate shaft of the second modified example of the sixth embodiment. In addition, the same code | symbol is attached | subjected to the same component as what was demonstrated in embodiment mentioned above, and the overlapping description is abbreviate | omitted.

As shown in FIG. 72, in the second modification of the sixth embodiment, the first shaft 1M is located in front of the second shaft 2M. The first shaft 1M includes a stopper 14M. The stoppers 14M project radially from the outer peripheral surface of the base 13M. The stopper 14M is integrally formed with the base 13M. The stopper 14M overlaps the end face of the second fitting portion 21M when viewed from the axial direction. The stopper 14M is located at the rear of the first shock absorber 15M. Therefore, the distance from the end face of the second fitting portion 21M to the stopper 14M is smaller than the distance from the end face of the second fitting portion 21M to the first impact absorbing portion 15M.

When the first shaft 1M and the second shaft 2M move relative to each other, the stopper 14M contacts the end face of the second fitting portion 21M. The stopper 14M regulates the relative movement amount of the first shaft 1M and the second shaft 2M. Since the stopper 14M is located behind the first impact absorbing portion 15M, the stopper 14M contacts the second fitting portion 21M before the first impact absorbing portion 15M enters the second shaft 2M. Thus, the first shaft 1M can bend after being moved relative to the second shaft 2M.

The stopper 14M may be provided on the second shaft 2M. For example, the stopper 14M may be provided on the inner circumferential surface of the second shaft 2M and may overlap the first fitting portion 18M as viewed in the axial direction. In such a case, the distance from the end face of the first fitting portion 18M to the stopper 14M is preferably smaller than the distance from the end face of the second fitting portion 21M to the first impact absorbing portion 15M. Thus, the first fitting portion 18M contacts the stopper 14M before the first impact absorbing portion 15M enters the second shaft 2M. Thus, the first shaft 1M can bend after being moved relative to the second shaft 2M.

The stopper 14M may be connected to the base 13M by welding or the like. A C-shaped retaining ring or an E-shaped retaining ring may be used as the stopper 14M.

As described above, the intermediate shaft 85P includes the stopper 14M that regulates the relative movement amount of the first shaft 1M and the second shaft 2M.

As a result, since it is possible to adjust the relative movement amount of the first shaft 1M and the second shaft 2M, it is possible to prevent an excessive load from being applied to the second shaft 2M.

Third Modified Example of Sixth Embodiment
FIG. 73 is an enlarged cross-sectional view of a peripheral portion of a groove of a first impact absorbing portion in a third modified example of the sixth embodiment. In addition, the same code | symbol is attached | subjected to the same component as what was demonstrated in embodiment mentioned above, and the overlapping description is abbreviate | omitted.

As shown in FIG. 73, in the third modification of the sixth embodiment, the covering material 5M is provided in the first impact absorbing portion 15Q. The covering material 5M covers the surface (the first side surface 31M, the second side surface 33M, the bottom surface 35M, the first connection surface 36M, and the second connection surface 37M) of the first shock absorber 15Q facing the groove 3M. That is, the covering material 5M covers the inner peripheral surface of the groove 3M. In addition, the covering material 5M covers the main surface 150 which is the surface outside the groove 3M of the first impact absorbing portion 15Q. That is, in the third modification of the sixth embodiment, the covering material 5M covers the entire surface of the first impact absorbing portion 15Q. The covering material 5M is a rustproof film. The covering material 5M contains, for example, zinc or nickel. In other words, the surface of the first shock absorber 15Q is plated with zinc, nickel or the like.

In addition, the covering material 5M does not necessarily need to cover the whole surface of the 1st impact-absorbing part 15Q. The covering material 5M should just cover at least one part of the surface which faces the groove 3M of the 1st impact-absorbing part 15Q. The covering material 5M preferably covers at least the bottom surface 35M, the first connection surface 36M, and the second connection surface 37M. Further, the covering material 5M may be, for example, a grease. In this case, the viscosity of the grease is preferably high.

As described above, the steering device 80M according to the third modified example of the sixth embodiment includes the covering material 5M covering at least a part of the surface of the first impact absorbing portion 15Q facing the groove 3M. The covering material 5M is a rustproof film.

The first shock absorber 15Q is designed to transmit a predetermined torque (for example, 300 Nm). In the first impact absorbing portion 15Q having the groove 3M, the strength against torque of the portion corresponding to the groove 3M is low. Although the first shock absorber 15Q is designed in consideration of a sufficient safety factor, there is a possibility that the first shock absorber 15Q can not withstand a predetermined torque if rust occurs in the first shock absorber 15Q. is there. On the other hand, in the first impact absorbing portion 15Q, the covering material 5M suppresses the occurrence of rust on the surface facing the groove 3M. The reduction in strength of the portion corresponding to the groove 3M of the first impact absorbing portion 15Q is suppressed. The third modification of the sixth embodiment is particularly effective when disposed at a place where water such as rain may be applied.

When the covering material 5M is applied to the first modification of the sixth embodiment (or the second modification of the sixth embodiment) described above, the covering material 5M is closer to the groove 3M of the first impact absorbing portion 15Q. It is preferable to cover the major surface 150 which is the outer surface. As described in the first modification of the sixth embodiment, when a predetermined axial load is applied to the intermediate shaft 85MC, the first shaft 1M and the second shaft 2M move relatively. If a bending moment is also applied to the intermediate shaft 85MC, the second shaft 2M may be caught by the first impact absorbing portion 15Q. On the other hand, the main surface 150 is covered with the covering material 5M, whereby the friction between the second shaft 2M and the first impact absorbing portion 15Q is reduced. Therefore, even if the second shaft 2M contacts the first impact absorbing portion 15Q, the second shaft 2M is less likely to be caught by the first impact absorbing portion 15Q. For this reason, the movement of the second shaft 2M becomes smooth.

(4th modification of 6th Embodiment)
FIG. 74 is an enlarged cross-sectional view of a first shock absorber in a fourth modification of the sixth embodiment. In addition, the same code | symbol is attached | subjected to the same component as what was demonstrated in embodiment mentioned above, and the overlapping description is abbreviate | omitted.

As shown in FIG. 74, in the fourth modification of the sixth embodiment, the filler 6M is provided in the groove 3M. For example, the filler 6M is disposed in all of the plurality of grooves 3M. For example, the depth of the filler 6M is equal to the depth HM of the groove 3M (see FIG. 62). The filler 6M is preferably a resin or a rubber. Furthermore, the filler 6M is preferably a rubber which is a closed cell. The Young's modulus of the filler 6M is smaller than the Young's modulus of the first impact absorbing portion 15R. When a bending moment is applied to the first impact absorbing portion 15R, the filler 6M is easily deformed.

The depth of the filler 6M may be smaller than the depth HM (see FIG. 62) of the groove 3M. That is, the volume of the filler 6M embedded in one groove 3M may be smaller than the volume of one groove 3M. The filler 6M preferably covers the bottom surface 35M, the first connection surface 36M, and the second connection surface 37M. In addition, both the filler 6M and the covering 5M described in the third modification of the sixth embodiment may be provided in the groove 3M. That is, the covering material 5M may cover the first impact absorbing portion 15R, and the filling material 6M may cover the covering material 5M. The filler 6M may be, for example, grease. In this case, the viscosity of the grease is preferably high.

As described above, the steering device 80M of the fourth modified example of the sixth embodiment includes the filler 6M disposed in the groove 3M.

In the first impact absorbing portion 15R of the fourth modified example of the sixth embodiment, the filling material 6M makes it difficult for water to enter the groove 3M. For this reason, the generation of rust on the surface of the first impact absorbing portion 15R facing the groove 3M is suppressed. The reduction in strength of the portion of the first impact absorbing portion 15R corresponding to the groove 3M is suppressed. The fourth modification of the sixth embodiment is particularly effective when arranged at a place where water such as rain may be applied.

The filler 6M is a resin. This makes it difficult for the filler 6M to inhibit the deformation of the first impact absorbing portion 15R.

The filler 6M is rubber. This makes it difficult for the filler 6M to inhibit the deformation of the first impact absorbing portion 15R.

The filler 6M is a closed cell. Thereby, the increase in the weight of the first impact absorbing portion 15R is suppressed.

When the filler 6M is applied to the first modification of the sixth embodiment (or the second modification of the sixth embodiment), the volume of the filler 6M is the same as the volume of the groove 3M. Is preferred. Thereby, since the groove 3M is filled with the filler 6M, the outer peripheral surface of the first impact absorbing portion 15R becomes smooth. The friction between the second shaft 2M and the first impact absorbing portion 15R is reduced. Therefore, even if the second shaft 2M contacts the first impact absorbing portion 15R, the second shaft 2M is unlikely to be caught by the first impact absorbing portion 15R. For this reason, the movement of the second shaft 2M becomes smooth.

1H

lower shaft

1I, 1M first shaft 10H

base 10M hole

11, 11C, 11D, 11H, 11M base 125H, 125I

small diameter portion

13H, 13I,

13M base

14I,

14M stopper

15, 15A, 15D, 15E, 15E, 15F,

15G shock absorbers

15C, 15H, 15I, 15J, 15K, 15M, 15R first shock absorbers 150, 150I main surface 16C base 16H stopper 16M base 17C, 17M second shock absorber 17H lower fitting portion 170H, 170I recessed

portion

171C, 171M

first connection portion

175C, 175M

small diameter portion

179C, 179M second connection portion 17aH male spline (male serration)
17aI Serration (spline)
18aM serration (spline)

180M recess

19, 19C, 19D, 19I, 19M base 2H upper shaft 2I, 2M second shaft 21H upper fitting portion 21aH female spline (female serration)
21aI Serration (spline)
21aM serration (spline)
23H, 23I, 23M large diameter portions 25H, 25I, 25M base 3, 3A, 3B, 3C, 3D (3aD, 3bD, 3cD, 3dD, 3eD, 3fD, 3hD, 3iD, 3jD, 3kD), 3E (3aE , 3bE, 3cE, 3dE, 3eE), 3F (3aF, 3bF, 3cF, 3dF, 3eF, 3fF), 3G (3aG, 3bG, 3cG, 3dG, 3eG, 3fG, 3gG, 3hG, 3iG, 3jG 3kG) , 3H, 3I, 3M grooves 31, 31B, 31C, 31D, 31I, 31M first side surfaces 33, 33B, 33C, 33D, 33H, 33I, 33M second side surfaces 35, 35B, 35C, 35D, 35H, 35I , 35M bottom surface 36, 36B, 36C, 36D, 36aG, 36fG, 36H, 36I, 36M first connection surface 37, 37B , 37C, 37D, 37aG, 37fG, 37H, 37I, 37M second connection surface 4, 4C, 4D, 4H, 4I, 4M convex portion 5I, 5M coating material 6I, 6M filler 80, 80C, 80H, 80I , 80M steering device 81 steering wheel 82 steering shaft 82a input shaft 82b output shaft 83 steering force assist mechanism 85, 85C, 85D, 85E, 85F, 85G, 85H, 85I, 85L, 85M, 85MC, 85P, intermediate shaft 87 pinion Shaft 88 Steering gear 88a Pinion 88b Rack 89 Tie rod 90 ECU
92 reduction gear 93 electric motor 94 torque sensor 95 vehicle speed sensor 98 ignition switch 99 power supply

Claims

With the first universal joint,
A second universal joint disposed forward of the first universal joint;
An intermediate shaft located between the first universal joint and the second universal joint;
Equipped with
The intermediate shaft includes a first impact absorbing portion having a groove on an outer peripheral surface thereof.
The steering apparatus according to claim 1, wherein the intermediate shaft is a solid member.
The intermediate shaft includes a first shaft which is a solid member, and a cylindrical second shaft which is releasably connected to the first shaft,
The steering apparatus according to claim 1, wherein the first shaft comprises the first shock absorber.
The first shaft includes a first fitting portion having serrations on an outer peripheral surface thereof,
The second shaft includes a second fitting portion having serrations on an inner circumferential surface,
The first fitting portion is fitted to the second fitting portion;
The steering apparatus according to claim 3, wherein a maximum diameter of the first impact absorbing portion is smaller than a minimum diameter of the first fitting portion.
The intermediate shaft includes a first shaft which is a hollow member whose inner diameter is constant over the entire axial length,
The steering apparatus according to claim 1, wherein the first shaft comprises the first shock absorber.
The steering apparatus according to claim 5, wherein the first shaft includes a second impact absorbing portion having an outer diameter smaller than an outer diameter of the first impact absorbing portion at a position corresponding to a bottom of the groove.
In a cross section obtained by cutting the first shaft in a plane perpendicular to the radial direction, at least a part of the surface of the first shock absorber facing the groove draws a first arc, and the second shock absorber At least a portion of the surface draws a second arc,
The steering apparatus according to claim 6, wherein a curvature radius of the second arc is larger than a curvature radius of the first arc.
The steering apparatus according to claim 6 or 7, wherein the minimum thickness of the second impact absorbing portion is 10% or more and 20% or less of the outer diameter of the second impact absorbing portion.
The steering apparatus according to any one of claims 5 to 8, wherein the intermediate shaft includes a cylindrical second shaft which is releasably connected to the first shaft.
The first impact absorbing portion includes a plurality of the grooves.
The steering device according to any one of claims 1 to 9, wherein the groove is annular.
The steering apparatus according to any one of claims 1 to 9, wherein the groove is helical.
The maximum width of the groove is 1 mm or more and 3 mm or less,
In a cross section obtained by cutting the intermediate shaft in a plane perpendicular to the radial direction, at least a portion of the surface of the first impact-absorbing portion facing the groove has a curvature radius of 0.2 mm or more and 1.0 mm or less The steering apparatus according to any one of claims 1 to 11, which draws a circular arc.
The steering apparatus according to any one of claims 1 to 12, wherein a width of the groove decreases toward a bottom of the groove.
An intermediate shaft used in a steering system,
An intermediate shaft comprising a first impact absorbing portion having a groove in an outer peripheral surface.