JP2013112113A - Steering device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the size and cost of a steer-by-wire type steering device having a steering actuator provided on a wheel side.SOLUTION: The steering device includes: a bearing part 5 which is provided on the side of a vehicle body; a T-shaped steering central shaft 10 which has a horizontal shaft part 11 supported by the bearing part 5; a hub carrier which is mounted on the wheel side; and the steering actuator which is fixed to an upper bracket and externally fitted to a vertical shaft part 12 of the steering central shaft 10, and which can be rotated integrally with the hub carrier around the axial center of the vertical shaft part 12. The side of the vehicle body and the steering central shaft 10 are connected together via a hinge to simplify a structure and achieve cost reduction. Since the simplification of the structure shortens a distance between the steering central shaft and the vehicle body, a reduction in vehicle height, by extension, size-reduction thereof can be achieved.

Description

  The present invention relates to a steer-by-wire steering device and a vehicle including the steering device.

As a wheel steering device in a vehicle, a so-called steer-by-wire type steering device mechanically separated from a steering input unit including a handle is known.
Specifically, as this type of steering device, as in Patent Document 1, a hub carrier attached to the wheel side, a motor provided on the vehicle body side, and a ball screw mechanism driven by this motor are used. There is known a rudder actuator and a tie rod that links the hub carrier arm and the nut of the ball screw mechanism of the actuator.

In such a steering device, the nut of the ball screw mechanism reciprocates when the motor provided on the vehicle body rotates forward and backward by a predetermined number of rotations in response to an operation with a predetermined steering angle in the steering input unit.
The tie rod coupled to the nut pushes and pulls the arm of the hub carrier, so that the hub carrier is tilted, and the wheel is given a turning angle corresponding to the operation at the steering input portion. .

Thus, although the steering apparatus of patent document 1 is what the steering actuator provided in the vehicle body side, the applicant is using the steering apparatus 2 which provided the steering actuator as shown in FIG. 4 in the wheel side. We are developing.
This steered device 2 is a steerer that rotates a steered central shaft 10 that serves as a rotational center of steering, a hub carrier 20, and a hub carrier 20 (including a wheel W) about the axis of the steered central shaft 10. An actuator 30.

  Here, the pin-type steered central shaft 10 is supported on the vehicle body side via the upper suspension arm S1 and the universal joint J so that the axial center of the pin-type steered central shaft 10 is substantially in the vertical direction.

  Further, the upper bracket 21 of the hub carrier 20 extends substantially horizontally from the inside of the wheel W, and is attached to the wheel side so that the upper surface thereof faces the lower end of the turning center shaft 10. Further, the steered actuator 30 is fixed to the upper bracket 21 and is fitted on the steered central shaft 10.

A worm wheel 13 is formed on the outer periphery of the turning center shaft 10, and the turning actuator 30 includes a driven shaft 31 and a motor 32. The worm wheel 13, the driven shaft 31, and the motor 32 are all casings. 40.
The driven shaft 31 is rotatably supported in the casing so that its axis is substantially horizontal. A worm 31a formed on the outer periphery of the driven shaft 31 meshes with the worm wheel 13 of the turning center shaft 10, and a motor 32. Thus, the rotational driving force can be transmitted.

  Now, when the driven shaft 31 is rotated by the motor 32, the driven shaft 31 turns around the steered central shaft 10 when the turning central shaft 10 meshing with the driven shaft 31 is prevented from rotating. Here, since the hub carrier 20 rotates integrally with the driven shaft 31 via the casing 40, the wheel W is steered.

  Since this steering device is not an aspect in which the components of the device are arranged in parallel in the vehicle axle direction as in Patent Document 1, it does not require a large storage space, and the vehicle can be downsized to a certain extent. .

JP 2007-326459 A

  By the way, the above-mentioned turning device is connected to the suspension arm on the vehicle body side and the turning center shaft through a universal joint having a relatively large size, so that the vehicle height becomes high, and the vehicle is downsized. There is room for.

In addition, since the universal joint is relatively expensive, there is room for improvement in terms of cost.
In particular, when a universal joint is used, it is necessary to stop the turning center axis to be troublesome. As a suspension function, basically it is sufficient if it can cope with the vertical movement of the wheel, so a joint with a high degree of freedom such as a universal joint has excessive performance.

  Therefore, the problem to be solved by the present invention is to reduce the size and cost of a steer-by-wire type steering apparatus in which a steering actuator is provided on the wheel side.

  In order to solve the above problems, the present invention is such that a turning center shaft is directly coupled to a vehicle body side by a hinge structure in a turning device provided with a turning actuator on the wheel side.

  More specifically, the steering device of the present invention is composed of a pair of opposed bearing portions provided on the vehicle body side, an integral horizontal shaft portion and a vertical shaft portion, and both end portions of the horizontal shaft portion are connected to the bearing portion. A T-shaped turning center shaft that is rotatably supported, a hub carrier that is attached to the wheel side and extends in a substantially horizontal direction is opposed to a lower end of a longitudinal axis portion of the turning center shaft, and the upper A steering actuator that is fixed to the bracket and that is externally fitted to the vertical axis of the steering central axis and that can rotate integrally with the hub carrier around the axis of the vertical axis. .

Since the turning center shaft is directly coupled to the vehicle body side by the hinge structure, the universal joint can be omitted, and the cost can be reduced.
Further, since the distance between the turning center axis and the vehicle body side can be shortened, the vehicle can be downsized.
Even with the hinge structure, there is no particular inconvenience as a suspension function because it can cope with the vertical movement of the wheel. In addition, since the structure is simplified, it is resistant to failure.

Partially cutaway front view of the steering device of the embodiment The principal part longitudinal cross-sectional view of the steering apparatus of embodiment Cross-sectional view of main parts of the steering device of the embodiment Partially cutaway front view of the applicant's developed steering system

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
The steered device 1 of the embodiment is a so-called steer-by-wire steered device mechanically separated from a steering input unit including a handle.

As shown in FIG. 1, the steering apparatus 1 according to the embodiment is arranged at the lower part of the vehicle, so that the center of gravity of the entire vehicle can be lowered, and the tire fender F of the vehicle as shown in the figure. Since it is a size that can be almost accommodated in the wheel house under the fender, the entire vehicle can be reduced in size.
The steering device 1 according to this embodiment includes a bearing portion 5, a turning center shaft 10, a hub carrier 20, and a turning actuator 30, and a part of the turning center shaft 10 and the turning actuator 30. Is accommodated in the casing 40.

  As shown in FIG. 2, the vehicle includes suspension arms S <b> 1 and S <b> 2 that are arranged in parallel vertically, and a tip portion of the upper suspension arm S <b> 1 is bifurcated to constitute a bearing portion 5.

The turning center shaft 10 is composed of a cylindrical horizontal axis portion 11 and a vertical axis portion 12 and has a T-shaped appearance. Both end portions of the horizontal shaft portion 11 are supported by the bearing portion 5, and the horizontal shaft portion 11 can rotate around the axis.
Therefore, the vertical axis portion 12 that is integral with the horizontal axis portion 11 and faces substantially in the vertical direction can swing in the vertical direction around the axis of the horizontal axis portion 11.
On the other hand, since the horizontal shaft portion 11 is constrained to the bearing portion 5 so that only the hinge movement is possible as described above, the vertical axis portion 12 is prevented from rotating around the axis.
Further, a reduced diameter portion 12a is formed on the distal end side of the vertical axis portion 12 of the turning center shaft 10, and a worm wheel 13 is fixed to the outer periphery of an intermediate portion of the reduced diameter portion 12a.
The reduced diameter portion 12a vertically penetrates an opening provided in the casing 40, and the upper and lower portions of the worm wheel 13 of the reduced diameter portion 12a are rotatable relative to the casing 40 via the rolling bearing 41. It is supported.

Next, the hub carrier 20 is attached to the wheel W, and has an upper bracket 21 that protrudes almost horizontally from the inner surface of the wheel W at the top. As such a hub carrier 20, a widely used one can be used.
The upper bracket 21 has an upper surface facing the lower end of the turning center shaft 10, and the casing 40 is fixed by appropriate means such as bolting.
The lower portion of the hub carrier 20 is coupled to the tip of the lower suspension arm S2 of the vehicle via a ball joint 22.

The steered actuator 30 further includes a driven shaft 31 and a motor 32.
In the casing 40, the driven shaft 31 is supported by rolling bearings 42 at both ends so that the shaft center is substantially horizontal.
The driven shaft 31 has a worm 31a fixed to the outer periphery of the intermediate portion thereof, and the worm 31a meshes with the worm wheel 13 of the turning center shaft 10 substantially perpendicularly. Further, a spur gear 31 b is fixed to the outer periphery of one end of the driven shaft 31.
On the other hand, the motor 32 is accommodated below the driven shaft 31 in the casing 40 so that the rotating shaft thereof is substantially parallel to the driven shaft 31. As shown in FIG. 1, the lower half of the motor 32 is positioned below the upper bracket 21.
A spur gear 32 a is fixed to the outer periphery of the rotating shaft of the motor 32, and meshes with the spur gear 31 b of the driven shaft 31.

The configuration of the steering device 1 according to the embodiment is as described above. When the rotating shaft of the motor 32 of the steering actuator 30 is driven, the rotational driving force is transmitted to the driven shaft 31 via the spur gears 32a and 31b. The
Here, the worm 31a of the driven shaft 31 and the worm wheel 13 of the vertical axis portion 12 of the turning center shaft 10 are engaged with each other, and the turning center shaft 10 is restrained by the upper suspension arm S1 so that the vertical axis portion thereof. 12 is prevented from rotating. Therefore, the driven shaft 31 rotates (revolves) around the axis of the longitudinal axis portion 12 of the turning center shaft 10 while rotating around the axis (rotating).

The casing 40 (and the motor 32) that accommodates and supports the driven shaft 31 also rotates integrally around the axis of the longitudinal axis portion 12 of the steered central shaft 10. For this reason, the hub carrier 20 to which the casing 40 is fixed also rotates, and the wheel W to which the hub carrier 20 is attached is steered.
If the forward / reverse rotation speed of the motor 32 of the steering actuator 30 is determined in advance according to an operation with a predetermined steering angle in a steering input unit (not shown), the wheel W can be rotated corresponding to the operation in the steering input unit. The steering angle is given.

  Note that the vertical movement of the wheel W during traveling of the vehicle can be absorbed by the vertical axis portion 12 of the turning center shaft 10 to which the turning actuator 30 is fitted, swinging up and down.

  It should be considered that the embodiments disclosed herein are illustrative and non-restrictive in every respect. The scope of the invention is indicated by the claims, and is intended to include all modifications and variations within the scope of the claims.

For example, the bearing portion 5 is not limited to the one provided at the tip of the suspension arm S1, and may be fixed to the chassis by bolting or the like.
Further, the structure of the steered actuator 30 is not particularly limited to the embodiment, and even when the structure of the steered actuator 30 is as in the embodiment, the arrangement of the driven shaft 31 and the motor 32 is not particularly limited. The shaft 31 may be arranged on the lower side and the motor 32 on the upper side.

DESCRIPTION OF SYMBOLS 1 Steering apparatus 2 Embodiment Steering apparatus 5 developed conventionally Bearing part 10 Steering center axis 11 Horizontal axis part 12 Vertical axis part 12a Diameter reduction part 13 Worm wheel 20 Hub carrier 21 Upper bracket 22 Ball joint 30 Steering actuator 31 driven shaft 31a worm 31b spur gear 32 motor 32a spur gear 40 casing 41 rolling bearing 42 rolling bearing F fender W wheel S1 upper suspension arm S2 lower suspension arm J universal joint

Claims (3)

A steer-by-wire vehicle steering device mechanically separated from a steering input unit,
A pair of opposed bearings 5 provided on the vehicle body side;
A T-shaped steered central shaft 10 which is composed of an integral horizontal shaft portion 11 and a vertical shaft portion 12, and both end portions of the horizontal shaft portion 11 are rotatably supported by the bearing portion;
A hub carrier 20 attached to the wheel side and having an upper bracket 21 extending in a substantially horizontal direction facing the lower end of the longitudinal axis portion 12 of the steered central shaft 10;
A steering actuator 30 fixed to the upper bracket 21 and externally fitted to the vertical axis portion 12 of the steering central shaft 10 and rotatable integrally with the hub carrier 20 around the axis of the vertical axis portion 12; A steering apparatus comprising: The vertical axis portion 12 of the turning center shaft 10 has a worm wheel 13 formed on the outer periphery thereof,
The steering actuator 30 includes:
A worm 31a that meshes with the worm wheel 13 is formed on the outer periphery thereof, and a driven shaft 31 that is rotatably supported around an axis that faces substantially the horizontal direction;
The steering apparatus according to claim 1, further comprising: a motor 32 that is disposed below the driven shaft 31 and that transmits a rotational driving force from a rotating shaft whose axis is substantially parallel to the driven shaft 31. Steering device 1 according to claim 1 or 2,
A vehicle body having a bearing portion 5 of the steering device;
A vehicle provided with a wheel W to which the hub carrier 20 of the steering device is attached.

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