JP6939123B2 - Steering device and intermediate shaft - Google Patents

Description

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 the operation of the operator (driver) to the steering wheel to the wheels. A steering device is known 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 provided with a tubular bellows. According to Patent Document 1, the impact is absorbed by the deformation of the bellows at the time of the first collision.

Japanese Unexamined Patent Publication No. 2005-145164

However, the production of tubular bellows requires dedicated and expensive equipment. Further, in order to change the deformation characteristics of the bellows according to the impact absorption performance individually required, it is necessary to change the mold. Therefore, there has been a demand for an intermediate shaft that 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 that absorbs an impact by an intermediate shaft that can be easily manufactured and whose deformation characteristics can be easily changed.

In order to achieve the above object, the steering device of one aspect of the present invention includes a first universal joint, a second universal joint arranged on the front side of the first universal joint, the first universal joint, and the first universal joint. 2. An intermediate shaft, which is a solid member for connecting the universal joint, is provided, and the intermediate shaft includes a shock absorbing portion having a groove on the outer peripheral surface.

As a result, a mold is not required to form the shock absorbing portion, so that the shock absorbing portion can be easily formed. Further, the deformation characteristics of the shock absorbing portion change according to the shape of the groove of the shock absorbing portion. Since it is easy to change the shape of the groove, it is easy to adjust the deformation characteristics of the shock absorbing portion. Therefore, the steering device can absorb the impact by the intermediate shaft which can be easily manufactured and whose deformation characteristics can be easily changed.

As a desirable aspect of the steering device, it is desirable that the shock absorbing portion includes a plurality of the grooves, and the grooves are annular.

As a result, when bending stress acts on the intermediate shaft, stress concentration occurs in a plurality of parts of the impact absorbing portion. Therefore, the range of the deformed portion of the shock absorbing portion tends to be large, so that the shock absorbing capacity of the intermediate shaft is improved. Further, since the groove is annular, it is difficult to limit the bending direction of the intermediate shaft.

As a desirable aspect of the steering device, it is desirable that the groove is spiral.

As a result, when bending stress acts on the intermediate shaft, stress concentration occurs in a plurality of parts of the impact absorbing portion. Therefore, the range of the deformed portion of the shock absorbing portion tends to be large, so that the shock absorbing capacity of the intermediate shaft is improved. Further, since the groove is spiral, the bending direction of the intermediate shaft is less likely to be limited.

As a desirable aspect of the steering device, the maximum width of the groove is 1 mm or more and 3 mm or less, and the surface of the shock absorbing portion facing the groove in a cross section obtained by cutting the intermediate shaft in a plane perpendicular to the radial direction. It is desirable to draw an arc having a radius of curvature of 0.2 mm or more and 1.0 mm or less at least in part.

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

As a desirable aspect of the steering device, it is desirable that the width of the groove decreases toward the bottom of the groove.

As a result, stress concentration is likely to occur when bending stress is applied to the intermediate shaft.

The intermediate shaft according to one aspect of the present invention is an intermediate shaft that is a solid member used in a steering device, and includes a shock absorbing portion having a groove on the outer peripheral surface.

As a result, a mold is not required to form the shock absorbing portion, so that the shock absorbing portion can be easily formed. Further, the deformation characteristics of the shock absorbing portion change according to the shape of the groove of the shock absorbing portion. Since it is easy to change the shape of the groove, it is easy to adjust the deformation characteristics of the shock absorbing portion. Therefore, the intermediate shaft can be easily manufactured and its deformation characteristics can be easily changed.

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

FIG. 1 is a schematic view of the steering device of the present embodiment. FIG. 2 is a perspective view of the steering device of the present embodiment. FIG. 3 is a side view of the intermediate shaft of the present embodiment. FIG. 4 is a cross-sectional view taken along the line AA in FIG. FIG. 5 is an enlarged view of the peripheral portion 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 absorbing portion in the intermediate shaft of the first modification. FIG. 8 is an enlarged view of a peripheral portion of the groove in the intermediate shaft of the second modification.

Hereinafter, the present invention will be described in detail with reference to the drawings. The present invention is not limited to the embodiments for carrying out the following inventions (hereinafter referred to as embodiments). In addition, the components in the following embodiments include those that can be easily assumed by those skilled in the art, those that are substantially the same, that is, those in a so-called equal range. Further, the components disclosed in the following embodiments can be appropriately combined.

(Embodiment)
FIG. 1 is a schematic view of the steering device of the present embodiment. FIG. 2 is a perspective view of the steering device of the present 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 in which the force given by the operator is transmitted. And a second universal joint 86 are provided and joined to the pinion shaft 87. In the following description, the front of the vehicle equipped with the steering device 80 is simply referred to as the front, and the rear of the vehicle is simply referred to 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 88a and a rack 88b. The pinion 88a is connected to the pinion shaft 87. The rack 88b meshes with the pinion 88a. The steering gear 88 converts the rotational motion transmitted to the pinion 88a into a straight motion by the rack 88b. The rack 88b is connected to the tie rod 89. The angle of the wheel changes as the rack 88b moves.

As shown in FIG. 1, the steering force assist mechanism 83 includes a speed reducing device 92 and an electric motor 93. The speed reducer 92 is, for example, a worm speed reducer. The torque generated by the electric motor 93 is transmitted to the worm wheel via the worm inside the speed reducer 92 to rotate the worm wheel. The speed reducer 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 82a 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 acquires signals from each of the torque sensor 94 and the vehicle speed sensor 95. Electric power is supplied to the ECU 90 from the power supply device 99 (for example, an in-vehicle battery) with the ignition switch 98 turned on. The ECU 90 calculates the auxiliary steering command value based on the steering torque and the vehicle speed. The ECU 90 adjusts the electric power value supplied to the electric motor 93 based on the auxiliary 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. By controlling the electric motor 93 by the ECU 90, the force required to operate the steering wheel 81 is reduced.

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

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

The base 11 is connected to the first universal joint 84. The diameter of the base 11 is constant. The shock absorbing portion 15 is located in front of the base portion 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 absorbing portion 15 includes a plurality of grooves 3 and a plurality of convex portions 4. The groove 3 is annular. The groove 3 is formed by cutting, for example. The plurality of grooves 3 are arranged at equal intervals in the axial direction. The convex portion 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 portion 11 and the base portion 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 connecting surface 36 is a curved surface connecting the first side surface 31 and the bottom surface 35. The second connecting 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. In the cross section shown in FIG. 5, the first connecting surface 36 and the second connecting surface 37 draw the same arc. The radius of curvature C1 of the arc drawn by the first connecting surface 36 and the second connecting surface 37 is preferably 0.2 mm or more and 1.0 mm or less. For example, the radius of curvature C1 in this embodiment is 0.3 mm.

The shock absorbing unit 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 shock 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 the first collision of the vehicle. Bending stress is generated in the intermediate shaft 85 due to the load applied to the steering gear 88. At this time, stress concentration occurs on the first connection surface 36 and the second connection surface 37, so that the shock absorbing portion 15 bends starting from the first connection surface 36 and the second connection surface 37. One side of the groove 3 in the radial direction expands, and the other side of the groove 3 in the radial direction contracts. On the side where the groove 3 contracts, the convex portion 4 comes into contact with the adjacent convex portion 4. The bent intermediate shaft 85 enters the gap between the peripheral parts of the intermediate shaft 85. By bending the shock absorbing portion 15, the shock caused by the collision is absorbed. As a result, the impact transmitted to the steering wheel 81 is reduced.

Since the shock absorbing portion 15 includes a plurality of grooves 3, when bending stress acts on the intermediate shaft 85, stress concentration occurs in the plurality of portions of the shock absorbing portion 15. Therefore, the range of the deformable portion of the shock absorbing portion 15 tends to be large, so that the shock absorbing capacity of the intermediate shaft 85 is improved.

The groove 3 of the shock absorbing portion 15 does not necessarily have the above-mentioned shape. For example, the first connecting surface 36 and the second connecting surface 37 may be connected without passing through the bottom surface 35. That is, in a cross section of the intermediate shaft 85 cut in a plane perpendicular to the radial direction, the surface of the shock absorbing portion 15 at a position corresponding to the bottom of the groove 3 may be a semicircle. Further, the first connection surface 36 and the second connection surface 37 may not be provided. That is, the first side surface 31 and the second side surface 33 may be directly connected to the bottom surface 35.

The number of grooves 3 provided in the shock absorbing unit 15 does not necessarily have to be the number shown in the figure. The shock absorbing portion 15 may have at least one groove 3.

The diameter D1 of the shock absorbing portion 15 at the position corresponding to the convex portion 4 does not necessarily have to be equal to the diameter of the base portion 11. The diameter D1 may be larger than the diameter D2 of the shock absorbing portion 15 at least at a position corresponding to the bottom of the groove 3. The diameter D1 may be smaller than the diameter of the base 11 or larger than the diameter of the base 11.

As described above, the steering device 80 includes the first universal joint 84, the second universal joint 86 arranged on the front side of the first universal joint 84, the first universal joint 84, and the second universal joint 86. The intermediate shaft 85, which is a solid member for connecting the above, is provided. The intermediate shaft 85 includes a shock absorbing portion 15 having a groove 3 on the outer peripheral surface.

As a result, a mold is not required to form 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 according to 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 shock absorbing portion 15. Therefore, the steering device 80 can absorb the impact by the intermediate shaft 85 which can be easily manufactured and whose deformation characteristics can be easily changed.

Further, in the steering device 80, the shock absorbing unit 15 includes a plurality of grooves 3. The groove 3 is annular.

As a result, when bending stress acts on the intermediate shaft 85, stress concentration occurs in a plurality of portions of the impact absorbing portion 15. Therefore, the range of the deformable portion of the shock absorbing portion 15 tends to be large, so that the shock absorbing capacity of the intermediate shaft 85 is improved. Further, since the groove 3 is annular, the bending direction of the intermediate shaft 85 is less likely 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 of the intermediate shaft 85 cut 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 radius of curvature 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 modification)
FIG. 7 is a side view of the shock absorbing portion in the intermediate shaft of the first modification. The same components as those described in the above-described embodiment are designated by the same reference numerals, and duplicate description will be omitted.

As shown in FIG. 7, the shock absorbing portion 15A of the first modification includes a groove 3A. The groove 3A is spiral. The above description of the maximum width W and the radius of curvature C1 of the groove 3 can also be applied to the groove 3A.

As a result, when bending stress acts on the intermediate shaft 85, stress concentration occurs in a plurality of portions of the impact absorbing portion 15A. Therefore, the range of the deformable portion of the shock absorbing portion 15A tends to be large, so that the shock absorbing capacity of the intermediate shaft 85 is improved. Further, since the groove 3A is spiral, the bending direction of the intermediate shaft 85 is less likely to be limited.

(Second modification)
FIG. 8 is an enlarged view of a peripheral portion of the groove in the intermediate shaft of the second modification. The same components as those described in the above-described embodiment are designated by the same reference numerals, and duplicate description will be omitted.

The shock absorbing portion 15B of the second modification includes a plurality of grooves 3B. As shown in FIG. 8, the shock absorbing portion 15B has a first side surface 31B, a second side surface 33B, a bottom surface 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 surface 31B and the second side surface 33B. The first connecting surface 36B is a curved surface connecting the first side surface 31B and the bottom surface 35B. The second connecting 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, stress concentration is likely to occur when bending stress is applied to the intermediate shaft 85.

11,19 Bases 15, 15A, 15B Shock absorbers 3, 3A, 3B Grooves 31, 31B First side surface 33, 33B Second side surface 35, 35B Bottom surface 36, 36B First connection surface 37, 37B Second connection surface 4 Convex Part 80 Steering device 81 Steering wheel 82 Steering shaft 82a Input shaft 82b Output shaft 83 Steering force assist mechanism 84 1st universal joint 85 Intermediate shaft 86 2nd universal joint 87 Pinion shaft 88 Steering gear 88a Pinion 88b Rack 89 Tie rod 90 ECU
92 Speed reducer 93 Electric motor 94 Torque sensor 95 Vehicle speed sensor 98 Ignition switch 99 Power supply

Claims (4)

With the first universal joint
A second universal joint arranged on the front side of the first universal joint,
An intermediate shaft, which is a solid member connecting the first universal joint and the second universal joint,
With
The intermediate shaft
A first base located on the first universal joint side, a second base located on the second universal joint side, and located between the first base and the second base, and e Bei a shock absorbing portion in which the groove of the plurality of annular is provided on the outer periphery, and
The groove of the shock absorbing portion is formed so as to be recessed inward in the radial direction from the outer peripheral surface.
The diameter of the first base, the diameter of the second base, and the diameter of the outer peripheral surface of the shock absorbing portion are the same.
All of the plurality of grooves are open radially outside and
Each of the plurality of grooves
The surfaces facing the grooves are a planar first side surface extending radially inward from the outer peripheral surface and a planar second side surface extending radially inward from the outer peripheral surface and facing the first side surface. And a flat bottom surface connecting the radial inner end of the first side surface and the radial inner end of the second side surface.
The width of the groove decreases toward the bottom of the groove because the first side surface and the second side surface approach each other toward the inside in the radial direction.
Steering device. The steering device according to claim 1, wherein the groove is spiral. 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 part of the surface of the shock absorbing portion facing the groove has an arc having a radius of curvature of 0.2 mm or more and 1.0 mm or less. draw
The steering device according to claim 1 or 2. An intermediate shaft that is used in a steering device and is a solid member that connects a first universal joint and a second universal joint arranged on the front side of the first universal joint.
A first base located on the first universal joint side, a second base located on the second universal joint side, and located between the first base and the second base, and e Bei a shock absorbing portion in which the groove of the plurality of annular is provided on the outer periphery, and
The groove of the shock absorbing portion is formed so as to be recessed inward in the radial direction from the outer peripheral surface.
The diameter of the first base, the diameter of the second base, and the diameter of the outer peripheral surface of the shock absorbing portion are the same.
All of the plurality of grooves are open radially outside and
Each of the plurality of grooves
The surfaces facing the grooves are a planar first side surface extending radially inward from the outer peripheral surface and a planar second side surface extending radially inward from the outer peripheral surface and facing the first side surface. And a flat bottom surface connecting the radial inner end of the first side surface and the radial inner end of the second side surface.
The width of the groove decreases toward the bottom of the groove because the first side surface and the second side surface approach each other toward the inside in the radial direction.
Intermediate shaft.

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