Steering device

Abstract

The present application provides a steering device capable of changing the steering angle of a wheel steered by a steering gear section while inhibiting the steering gear section from being complicated in structure. The steering device includes a steering gear section that steers a wheel, a link section that connects the steering gear section and the wheel, and a posture changing section provided between the steering gear section and a vehicle body and capable of moving the steering gear section relative to the vehicle body in at least one of a front-rear direction and a rotational direction in which the steering gear section rotates about a vertical axis.

Description

Technical Field

[0001] The present invention relates to a steering device that turns wheels by driving a steering gear. Background Technology

[0002] Patent Document 1 discloses a toe-angle adjustment mechanism for adjusting the toe-angle of the left and right wheels by changing the length of the rack shaft in a rack and pinion type vehicle steering system. This toe-angle adjustment mechanism includes: a first rack shaft connected to the right wheel; a second rack shaft connected to the left wheel; a switching unit for switching the relative movement direction of the first and second rack shafts during steering; and an electric motor for moving the first rack shaft axially.

[0003] The first rack shaft has: a pair of arms for integration with the second rack shaft during normal steering; and a hollow portion serving as a cylindrical space coaxially arranged with the first rack shaft. The second rack shaft has: a coaxial portion disposed within the hollow portion of the first rack shaft and located on the side of the second rack shaft for sliding; a vertical portion extending vertically relative to the coaxial portion and housing a telescopic mechanism; and a switching shaft extending parallel to the first rack shaft and the coaxial portion from the vertical portion.

[0004] Patent Document 1: Japanese Patent Application Publication No. 2005-297782 Summary of the Invention

[0005] The technology disclosed in Patent Document 1 has a mechanism that allows the rack shaft length to be variable, thus complicating the structure of the rack and pinion type steering gear section.

[0006] The purpose of this invention is to provide a steering device that can suppress the structural complexity of the steering gear section while changing the steering angle of the wheel that is steered by the steering gear section.

[0007] To address the aforementioned issues, one aspect of the steering device of the present invention includes: a steering gear portion that steers a wheel; a linkage portion that connects the steering gear portion to the wheel; and a posture changing portion disposed between the steering gear portion and the vehicle body, which enables the steering gear portion to move relative to the vehicle body in at least one of the longitudinal direction and the rotational direction about the upper and lower axes.

[0008] Invention Effects

[0009] According to the present invention, a steering device is provided that can suppress the complication of the steering gear section structure while changing the steering angle of the wheel that is steered by the steering gear section. Attached Figure Description

[0010] Figure 1 This is a diagram illustrating the configuration of the steering device and its surroundings in an embodiment.

[0011] Figure 2 This is a diagram illustrating the functional configuration of the steering device in an embodiment.

[0012] Figure 3 This is a diagram showing the steering device and its surrounding structure in the state where the steering gear moves forward.

[0013] Figure 4 This is a diagram showing the steering device and its surrounding structure in the state where the steering gear moves backward.

[0014] Figure 5 It is a diagram used to illustrate the operation of the steering mechanism when a vehicle turns. Detailed Implementation

[0015] Figure 1 This diagram illustrates the configuration of the steering device 10 and its surroundings in an embodiment. The steering device 10 is disposed on the front wheel side of the vehicle and steers the right wheel 18a and left wheel 18b (referred to as "wheels 18" without distinction) which are the front wheels. The vehicle equipped with the steering device 10 can perform autonomous driving control. The steering device 10 steers the wheels 18 according to the steering angle input by the driver or autonomous driving control.

[0016] The steering mechanism 10 includes a steering gear section 12, a posture changing section 16, a right connecting rod section 26a, and a left connecting rod section 26b. The steering gear section 12 has, for example, a gear in the form of a rack and pinion, such that moving the rack in the left-right direction causes the wheel 18 to turn. The steering gear section 12 includes a rack and pinion, a pinion, and a housing that houses them.

[0017] The housing of the steering gear unit 12 is fixed to the attitude change unit 16 via the mounting part 12a. The rack and pinion of the steering gear unit 12 is connected to the right link part 26a and the left link part 26b (referred to as "link part 26" without distinguishing between them) via rotatable joints.

[0018] Linkage 26 is a steering link that connects steering gear 12 and wheel 18. Right link 26a is rotatably connected to steering knuckle arm 22 of right steering knuckle 20a. Left link 26b is rotatably connected to steering knuckle arm 22 of left steering knuckle 20b.

[0019] The right wheel 18a steers around the right kingpin 24a. The left wheel 18b steers around the left kingpin 24b. The right wheel 18a and left wheel 18b steer by moving the rack of the steering gear 12 left and right. The steering angle relative to the fore-and-aft direction of the wheel 18 is sometimes referred to as the toe angle. Figure 1 In the initial state shown, the steering gear 12 is located further back than the right kingpin 24a by a position R.

[0020] The posture change unit 16 is disposed between the steering gear unit 12 and the vehicle body 14, and is capable of changing the posture of the steering gear unit 12. The posture change unit 16 is fixed to the housing of the steering gear unit 12 and to the suspension structure member that is part of the vehicle body 14.

[0021] The posture changing unit 16 is capable of moving the steering gear unit 12 relative to the vehicle body 14 in at least one of the longitudinal direction FR and the rotation direction S about the vertical axis. The posture changing unit 16 has a rotating shaft 28 connected to the steering gear unit 12. The rotating shaft 28 is arranged in the vertical direction to rotate the steering gear unit 12. Furthermore, the rotating shaft 28 rotates in the longitudinal direction FR. The rotating shaft 28 is also capable of moving in the longitudinal direction FR.

[0022] Figure 2 This is a diagram illustrating the functional configuration of the steering device 10 in an embodiment. Figure 2 In this context, the various components described as functional blocks for performing various processes can be constructed in hardware as circuit blocks, memory, and other LSIs, and implemented in software as programs loaded into memory. Therefore, those skilled in the art will understand that these functional blocks can be implemented in various forms, either solely in hardware, solely in software, or through combinations thereof, and are not limited to any one of them.

[0023] The steering system 10 includes an attitude change unit 16, a control unit 30, a vehicle height sensor 32, and a driving status detection sensor 34. The control unit 30 drives the attitude change unit 16 based on the detection results of the vehicle height sensor 32 and the driving status detection sensor 34.

[0024] The posture changing unit 16 includes a rotating shaft 28, an actuator 42, and a sliding part 44. The sliding part 44 is capable of sliding in the front-rear direction FR. The sliding part 44 is, for example, a mechanism that causes the rotating shaft 28 to slide in the front-rear direction FR.

[0025] Actuator 42 moves sliding part 44 in the front-rear direction FR and rotates rotating shaft part 28 in the rotation direction S. Actuator 42 may have a first actuator for moving sliding part 44 and a second actuator for rotating rotating shaft part 28, both of which can be driven by motors. Posture changing unit 16 may have a locking mechanism for locking the movement of rotating shaft part 28 and sliding part 44 respectively.

[0026] The vehicle height sensor 32 detects the vertical height of the vehicle body 14 and sends the detection result to the control device 30. The driving status detection sensor 34 detects the driving status of the vehicle and sends the detection result to the control device 30. The driving status detection sensor 34 includes a sensor that detects the turning angle of the vehicle, such as a steering angle detection sensor that detects the steering angle or rudder angle. In addition, the steering angle is the input of the driver, and the rudder angle is the output to the wheels 18.

[0027] The control device 30 includes an acquisition unit 36, a processing unit 38, and a control unit 40. The acquisition unit 36 ​​acquires the detection results from the vehicle height sensor 32 and the driving state detection sensor 34. The processing unit 38 sets the longitudinal position of the steering gear unit 12 based on the detection results from the vehicle height sensor 32. The processing unit 38 uses numerical formulas or two-dimensional graphs determined through experiments, etc., to derive the longitudinal position of the steering gear unit 12 from the vehicle height, and sends the derived position information of the steering gear unit 12 to the control unit 40.

[0028] The control unit 40 drives the actuator 42 based on the position information of the steering gear unit 12 derived from the processing unit 38. The control unit 40 drives the actuator 42 of the posture change unit 16 based on the height of the vehicle body 14, causing the sliding part 44 of the steering gear unit 12 to move in the front-rear direction, thereby setting the position of the steering gear unit 12 in the front-rear direction.

[0029] Figure 3 This diagram shows the steering device 10 and its surrounding structure in a state where the steering gear 12 is moving forward F. The sliding part 44 of the attitude change part 16 moves the steering gear 12 forward F relative to the vehicle body 14. Figure 3 In the middle, the connection position of the steering gear part 12 and the connecting rod part 26 is located from the rear R close to the connection position of the steering knuckle 20 and the connecting rod part 26 and is arranged in the left and right direction.

[0030] As a result, the connecting rod 26 lengthens in the left-right direction, pushing the steering knuckle 20 outwards from a position further rearward than the kingpin 24, thereby pushing the wheel 18 towards the inward tilt direction. For example, when the vehicle height decreases and the wheel 18 tilts outwards due to the load, the posture adjustment unit 16 can move the steering gear 12 forward by F to adjust the wheel 18 to the inward tilt side. Furthermore, when the load is low and the vehicle height increases, the posture adjustment unit 16 can move the steering gear 12 forward by F to adjust the wheel 18 to the inward tilt side, thereby improving straight-line driving performance.

[0031] Figure 4 This diagram shows the steering device 10 and its surrounding structure in a state where the steering gear section 12 moves rearward by R. The sliding part 44 of the attitude change section 16 causes the steering gear section 12 to move rearward by R relative to the vehicle body 14. Figure 4In the middle, the connection position of the steering gear part 12 and the connecting rod part 26 is far away from the connection position of the steering knuckle 20 and the connecting rod part 26.

[0032] As a result, the connecting rod 26 becomes shorter in the left-right direction, pulling the steering knuckle 20 inward further rearward than the kingpin 24, thereby pushing the wheel 18 towards the camber direction. For example, when the vehicle height increases and the wheel 18 becomes cambered, the posture change unit 16 can move the steering gear unit 12 rearward by R to adjust the wheel 18 to the camber side.

[0033] Furthermore, when the load is heavy and the vehicle height is low, the attitude adjustment unit 16 can move the steering gear unit 12 rearward by R to adjust the wheels 18 to the camber side, thereby improving cornering performance. The control unit 40 can drive the actuator 42 based on the detection result of the vehicle height sensor 32 when the ignition switch is turned on.

[0034] Figure 5 This diagram illustrates the operation of the steering device 10 when a vehicle is turning. Figure 5 (a) shows the state where the steering gear 12 is not rotating when the vehicle is turning. Figure 5 (b) shows the state of the steering gear 12 rotating when the vehicle is turning.

[0035] exist Figure 5 In (a), when the steering angle for left rotation is input, the left and right wheels 18 turn to the left. Since the steering gear 12 does not rotate, the wheels 18 steer at the normal gear ratio.

[0036] exist Figure 5 In (b), the input was the same as... Figure 5 (a) With the same left-hand rotation angle, but with the steering gear 12 rotating in the same left direction, the left and right wheels 18 turn to the left. Therefore, with Figure 5 Compared to the wheel 18 shown in (a), the wheel 18 steers to a greater extent. That is, the gear ratio of the steering angle relative to the steering angle becomes variable as the steering gear 12 rotates.

[0037] The processing unit 38 sets the rotation angle of the steering gear unit 12 according to the vehicle's driving state when the vehicle is turning. The processing unit 38 derives the rotation angle of the steering gear unit 12 based on the driving state such as the steering angle and vehicle speed, and sends the derived result to the control unit 40.

[0038] When the vehicle turns, the control unit 40 drives the posture change unit 16 according to the vehicle's driving state, thereby moving the steering gear unit 12 in the rotation direction around the rotation axis unit 28. This sets the position of the rotation direction of the steering gear unit 12. Thus, the gear ratio of the steering angle to the steering angle can be changed like a transmission gear.

[0039] When the vehicle turns, the control unit 40 drives the posture change unit 16 by rotating the steering gear unit 12 in the turning direction of the vehicle. That is, the control unit 40 rotates the rotation shaft unit 28 in the same direction as the turning direction of the vehicle, and the steering gear unit 12 rotates in the turning direction of the vehicle. As a result, it is possible to make the steering angle relative to the steering angle greater than the steering gear unit 12 without rotation.

[0040] When the vehicle speed is below the specified speed, the control unit 40 can control the posture change unit 16 so that when the steering angle increases, the rotation angle of the steering gear unit 12 around the rotation axis 28 increases.

[0041] The present invention has been described above based on embodiments. The present invention is not limited to the above embodiments, and various design changes and modifications can be made based on the knowledge of those skilled in the art.

[0042] In this embodiment, the steering device 10 is shown as being used for the front wheels, but the embodiment is not limited to this method. For example, the posture changing unit 16 provided on the steering gear unit 12 and the vehicle body 14 can be provided on the rear wheels. Alternatively, the posture changing unit 16 can be provided on both the front and rear wheels, not limited to the rear wheels.

[0043] Symbol Explanation

[0044] 10-Steering device, 12-Steering gear, 12a-Mounting part, 14-Body body, 16-Attitude change part, 18a-Right wheel, 18b-Left wheel, 20a-Right steering knuckle, 20b-Left steering knuckle, 22-Steering knuckle arm, 24a-Right kingpin, 24b-Left kingpin, 26a-Right connecting rod, 26b-Left connecting rod, 28-Rotating shaft, 30-Control device, 32-Vehicle height sensor, 34-Driving status detection sensor, 36-Acquisition part, 38-Processing part, 40-Control part, 42-Actuator, 44-Sliding part.

Claims

1. A steering device, characterized in that, have: Steering gears, which turn the wheels; Linkage portion, which connects the steering gear portion and the wheel; and The posture change unit is disposed between the steering gear unit and the vehicle body, and is capable of moving the steering gear unit relative to the vehicle body in at least one of the longitudinal direction and the rotational direction about the upper and lower axes.

2. The steering device according to claim 1, characterized in that, The steering device includes a control unit that drives the attitude change unit. The posture change unit enables the steering gear unit to move relative to the vehicle body in the forward and backward direction. The control unit drives the posture change unit according to the height of the vehicle body, thereby causing the steering gear unit to move in the forward and backward direction.

3. The steering device according to claim 1, characterized in that, The steering device includes a control unit that drives the attitude change unit. The posture change unit enables the steering gear unit to move relative to the vehicle body in the direction of rotation. When the vehicle turns, the control unit drives the posture change unit according to the vehicle's driving state, thereby causing the steering gear unit to move in the direction of rotation.

4. The steering device according to claim 3, characterized in that, When the vehicle turns, the control unit drives the posture change unit to rotate the steering gear unit in the turning direction of the vehicle.

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