Steering gearbox, suspension assembly, and steering system

Abstract

The present invention has a rack case 101, a rack bar 102 that is accommodated in the rack case 101, a pinion gear 103 that has a larger diameter than the rack case 101, penetrates the rack case 101, engages the rack bar 102, and is connected at one end to a steering column shaft 11, and a lock mechanism 120 that is assembled at the other end of the pinion gear 103 and allows the pinion gear 103 to rotate when in an inactive unlocked state but fixes the pinion gear 103 so as to prevent rotation thereof when in an active locked state.

Description

Steering gearboxes, suspension assemblies and steering systems

[0001] The present invention relates to a steering gearbox, a suspension assembly and a steering system.

[0002] The inventors are developing a vehicle that can be efficiently parked in extremely small spaces, with an eye toward the spread of self-driving vehicles and car sharing. It is desirable for such a vehicle to be able to move laterally and turn on the spot. Japanese Patent Application Laid-Open Publication No. 2016-55804 discloses technology that enables lateral movement and turning on the spot.

[0003] However, the above-mentioned conventional devices are difficult to install in a vehicle and are not easy to operate.

[0004] The present invention has been made in light of the above-mentioned problems in the prior art, and an object of the present invention is to provide a steering gear box, a suspension assembly, and a steering system that can be easily installed in a vehicle, have excellent operability, and enable lateral movement and rotation on the spot.

[0005] The present invention solves the above-mentioned problems by the following means. For ease of understanding, the reference numerals corresponding to the embodiments of the present invention are written in parentheses, but the present invention is not limited to these. Furthermore, the configurations described with reference numerals may be appropriately replaced or improved.

[0006] One embodiment is a steering gearbox (100) having: a rack case (101); a rack bar (102) housed in the rack case (101); a pinion gear (103) that is longer than the diameter of the rack case (101), passes through the rack case (101), meshes with the rack bar (102), and has one end connected to a steering column shaft (11); and a locking mechanism (120) that is attached to the other end of the pinion gear (103), allows the pinion gear (103) to rotate freely in an unlocked state when not activated, and fixes the pinion gear (103) so as not to rotate in a locked state when activated.

[0007] Another aspect is a suspension unit (40) having an actuator unit (50), wherein the suspension unit (40) comprises: a base member (41) having an axle (411) standing upright on a top surface, the axle (411) being inserted into a hole in the body frame (1) and attached to the body frame (1), a suspension arm (42) attached to the base member (41) so as to be able to swing freely, and a wheel attachment body (43) to which a wheel can be attached and attached to the suspension arm (42), wherein the actuator unit (50) comprises: a housing (51) attached above the axle (411) of the base member (41), an actuator (50) housed inside the housing (51) and capable of driving the axle (411) of the base member (41) by rotation of a rotation shaft, The suspension assembly (20) comprises: a locking mechanism (50) housed inside the housing (51) that allows the rotation shaft of the actuator (50) to rotate freely in an unlocked state when not in operation, and that allows the rotation shaft of the actuator (50) to rotate integrally with the housing (51) in a locked state when in operation; and a lever (60) that is fixed to the housing (51) and to which a tie rod (110) of a steering gearbox (100) is connected.

[0008] Yet another aspect is a steering system (10) having a steering gearbox (100), a right front wheel suspension assembly (210), a left front wheel suspension assembly (220), a right rear wheel suspension assembly (230), and a left rear wheel suspension assembly (240), wherein the steering gearbox (100) comprises: a rack case (101); a rack bar (102) housed in the rack case (101); a pinion gear (103) longer than the diameter of the rack case (101), passing through the rack case (101), meshing with the rack bar (102), and having one end connected to a steering column shaft (11); a locking mechanism (120) attached to the other end of the pinion gear (103), allowing the pinion gear (103) to rotate freely in an unlocked state when not in operation, and fixing the pinion gear (103) so as not to rotate in an locked state when in operation, the right front wheel suspension assembly (210) comprises: a right front wheel suspension unit (40); and a right front wheel actuator unit (50), the right front wheel suspension unit (40) comprising: a right front wheel base member (41) having a right front wheel axle portion (411) standing upright on the top surface, the right front wheel axle portion (411) being inserted into a hole in the body frame (1) and attached to the body frame (1), a right front wheel suspension arm (42) attached to the right front wheel base member (41) so as to be able to swing freely, a right front wheel mounting body (43) on which a wheel can be mounted and which is assembled to the right front wheel suspension arm (42), wherein the right front wheel actuator unit (50) comprises: a right front wheel housing (51) which is assembled above the right front wheel axle portion (411) of the right front wheel base member (41); a right front wheel actuator (50) housed inside the right front wheel housing (51) and which is capable of driving the right front wheel axle portion (411) of the right front wheel base member (41) by rotation of a rotary shaft;a right front wheel lock mechanism (50) that is housed inside the right front wheel housing (51) and that allows the rotation shaft of the right front wheel actuator (50) to rotate freely in an unlocked state when not in operation, and that allows the rotation shaft of the right front wheel actuator (50) to rotate integrally with the right front wheel housing (51) in a locked state when in operation, and a right front wheel lever (60) that is fixed to the right front wheel housing (51) and to which a tie rod (110) of a steering gear box (100) is connected, and the left front wheel suspension assembly (220) has a left front wheel suspension unit (40), and a left front wheel actuator unit (50), and the left front wheel suspension unit (40) a left front wheel base member (41) having a left front wheel axle (411) standing upright on the top surface, the left front wheel axle (411) being inserted into a hole in the body frame (1) and attached to the body frame (1); a left front wheel suspension arm (42) attached to the left front wheel base member (41) so as to be able to swing; a left front wheel mounting body (43) to which a wheel can be attached and attached to the left front wheel suspension arm (42); the left front wheel actuator unit (50) comprises: a left front wheel housing (51) attached above the left front wheel axle (411) of the left front wheel base member (41); a left front wheel actuator (50) housed inside the left front wheel housing (51) and capable of driving the left front wheel axle (411) of the left front wheel base member (41) by rotation of a rotary shaft; a left front wheel lock mechanism (50) that is housed inside the left front wheel housing (51) and that allows the rotation shaft of the left front wheel actuator (50) to rotate freely in an unlocked state when not in operation, and that allows the rotation shaft of the left front wheel actuator (50) to rotate integrally with the left front wheel housing (51) in a locked state when in operation, and a left front wheel lever (60) that is fixed to the left front wheel housing (51) and to which a tie rod (110) of a steering gear box (100) is connected, and the right rear wheel suspension assembly (230) comprises: a right rear wheel suspension unit (40);a right rear wheel actuator unit (50), wherein the right rear wheel suspension unit (40) comprises: a right rear wheel base member (41) having a right rear wheel axle portion (411) standing upright on the top surface, the right rear wheel axle portion (411) being inserted into a hole in the body frame (1) and attached to the body frame (1); a right rear wheel suspension arm (42) attached to the right rear wheel base member (41) so as to be able to swing; and a right rear wheel mounting body (43) to which a wheel can be attached and attached to the right rear wheel suspension arm (42), wherein the right rear wheel actuator unit (50) is attached above the right rear wheel axle portion (411) of the right rear wheel base member (41), and comprises: a right rear wheel housing (51); a right rear wheel actuator (50) housed inside the right rear wheel housing (51) and capable of driving a right rear wheel axle portion (411) of the right rear wheel base member (41) by rotation of a rotary shaft; and a right rear wheel locking mechanism (50) housed inside the right rear wheel housing (51) and allowing the rotary shaft of the right rear wheel actuator (50) to rotate freely in an unlocked state when not in operation, and allowing the rotary shaft of the right rear wheel actuator (50) to rotate integrally with the right rear wheel housing (51) in a locked state when in operation, wherein the left rear wheel suspension assembly (240) comprises: a left rear wheel suspension unit (40); and a left rear wheel actuator unit (50), wherein the left rear wheel suspension unit (40) comprises: a left rear wheel base member (41) having a left rear wheel axle portion (411) standing upright on the top surface, the left rear wheel axle portion (411) being inserted into a hole in the body frame (1) and attached to the body frame (1); a left rear wheel suspension arm (42) attached to the left rear wheel base member (41) so as to be able to swing; and a left rear wheel mounting body (43) to which a wheel can be attached and attached to the left rear wheel suspension arm (42), wherein the left rear wheel actuator unit (50) is attached above the left rear wheel axle portion (411) of the left rear wheel base member (41), and comprises a left rear wheel housing (51);The steering system (10) comprises: a left rear wheel actuator (50) housed inside the left rear wheel housing (51) and capable of driving the left rear wheel axle portion (411) of the left rear wheel base member (41) by rotation of a rotary shaft; and a left rear wheel locking mechanism (50) housed inside the left rear wheel housing (51) and allowing the rotary shaft of the left rear wheel actuator (50) to rotate freely in an unlocked state when not in operation, and allowing the rotary shaft of the left rear wheel actuator (50) to rotate integrally with the left rear wheel housing (51) in a locked state when in operation.

[0009] FIG. 1 is a perspective view showing a steering system mounted on a vehicle body frame. FIG. 2 is a perspective view showing a suspension unit. FIG. 3 is a perspective view showing a suspension assembly. FIG. 4A is a side view showing the suspension assembly, and FIG. 4B is a front view. FIG. 5 is a perspective view showing the suspension assembly shown in FIGS. 3 and 4A-B used for a front wheel and assembled to a vehicle body frame. FIG. 6 is a perspective view showing a steering gearbox. FIG. 7A is a plan view showing the steering gearbox, FIG. 7B is a cross-sectional view taken along line B-B of FIG. 7A, and FIG. 7C is a cross-sectional view taken along line C-C of FIG. 7A. FIG. 8 is a diagram showing a steering system centered around a controller. FIG. 9 is a diagram showing an operation touch panel. FIG. 10 is a flowchart executed by the controller in normal driving mode. FIG. 11 is a diagram showing the state of the wheels in normal driving mode. FIG. 12 is a diagram showing an operation touch panel in rotate-on-the-spot mode. FIG. 13 is a flowchart executed by the controller in rotate-on-the-spot mode. FIG. 14 is a diagram showing the state of the wheels in the rotate mode. FIG. 15 is a diagram showing the operation touch panel in the parallel mode. FIG. 16 is a flowchart executed by the controller in the parallel mode 1. FIG. 17 is a diagram showing the state of the wheels in the parallel mode 1. FIGS. 18A-C are diagrams explaining issues in the parallel mode. FIG. 19 is a flowchart executed by the controller in the parallel mode 2. FIGS. 20A-C are diagrams showing the state of the wheels when the parallel mode 2 is executed. FIGS. 21A-C are diagrams explaining the running state of the vehicle when the parallel mode 2 is executed. FIG. 22 is a flowchart executed by the controller in the slanting mode. FIG. 23 is a diagram showing the state of the wheels in the slanting mode. FIG. 24 is a flowchart executed by the controller in the small turn mode.FIG. 25 is a diagram showing the state of the wheels in small turn mode.

[0010] The embodiments of the present invention, the advantages of the present invention will be described in detail below with reference to the accompanying drawings.

[0011] (First embodiment) Fig. 1 is a perspective view showing a steering system mounted on a body frame. The steering system 10 includes a steering gearbox 100, a right front wheel suspension assembly 210, a left front wheel suspension assembly 220, a right rear wheel suspension assembly 230, and a left rear wheel suspension assembly 240. The steering gearbox 100 is mounted to the body frame 1. The right front wheel suspension assembly 210 and the left front wheel suspension assembly 220 are also mounted to the body frame 1. The steering gearbox 100 is connected to a steering wheel 12 via a steering column shaft 11. The steering gearbox 100 is also connected to the right front wheel suspension assembly 210 and the left front wheel suspension assembly 220. When a driver operates the steering wheel 12, the steering angles of the right front wheel and the left front wheel change. A right rear wheel suspension assembly 230 and a left rear wheel suspension assembly 240 are also assembled to the body frame 1 .

[0012] FIG. 2 is a perspective view showing the suspension unit.

[0013] The suspension unit 40 is of a double wishbone type and mainly comprises an upright 41, suspension arms 42 (upper suspension arms 421 and lower suspension arms 422), and a wheel mounting body 43. In the following description, the upper suspension arms will be referred to as "upper arms" where appropriate, and the lower suspension arms will be referred to as "lower arms" where appropriate.

[0014] The upright 41 is a base member to which the suspension arms 42 (upper arms 421, lower arms 422) and the like are attached. As will be described later, the upright 41 is attached to the body frame 1. A shaft 411 is fixedly provided upright on the top surface 41a of the upright 41. As will be described later, this shaft 411 is inserted into a hole in the body frame 1, and the upright 41 is attached to the body frame 1.

[0015] The upper arm 421 is a substantially V-shaped member as shown in Fig. 3 described below. A hole for passing a pivot shaft 4211 is formed near the base end of the upper arm 421. A hole for passing a pivot shaft 4212 is formed near the tip of the upper arm 421. The upper arm 421 is supported by the upright 41 via the pivot shaft 4211.

[0016] The lower arm 422 is a generally H-shaped member having two arm portions 4221 and a connecting portion 4222 that connects the two arm portions 4221. The connecting portion 4222 connects the lower portions of the two arm portions 4221. A hole for passing a pivot shaft 4223 is formed near the base end of the arm portion 4221 of the lower arm 422. A hole for passing a pivot shaft 4224 is formed near the tip of the arm portion 4221 of the lower arm 422. The lower arm 422 is supported by the upright 41 via the pivot shaft 4223.

[0017] The wheel mounting body 43 is a member that mounts the wheel 400 via an axle. The wheel mounting body 43 is mounted near the tip of the upper arm 421 and the lower arm 422 via a pivot shaft 4212 and a pivot shaft 4224. The wheel mounting body 43 illustrated in FIG. 2 is a motor that drives the wheel 400, and a housing 431 is attached to the upper arm 421 and the lower arm 422.

[0018] 3 is a perspective view showing the suspension assembly 20. The suspension assembly 20 is formed by assembling an actuator unit 50 to a suspension unit 40.

[0019] The suspension assembly 20 is assembled to the body frame 1 by inserting the shaft 411 of the suspension unit 40 into the body frame 1 and fastening the fixing member 30 to the body frame 1 with bolts 31. An actuator unit 50 is assembled above the shaft 411. The actuator unit 50 incorporates an actuator and a locking mechanism, as well as a reducer and a rotary encoder. The rotary encoder detects the orientation of the upright 41 (suspension unit 40). A lever 60 is fixed to the housing 51 of the actuator unit 50. This lever 60 is required for the front wheel suspension assemblies 210, 220, but may or may not be provided for the rear wheel suspension assemblies 230, 240.

[0020] Next, the structure of the suspension assembly will be further described with reference to a side view of the suspension assembly shown in FIG. 4A and a front view of the suspension assembly shown in FIG. 4B.

[0021] 4B, a hole for attaching the lower arm 422 is formed at the lower end of the upright 41. A hole near the base end of the arm portion of the lower arm 422 is aligned with this hole, and a pivot shaft 4223 is inserted, thereby attaching the lower arm 422 to the upright 41 so that it can swing freely.

[0022] In addition, a hole for attaching the upper arm 421 is formed directly above the hole into which the pivot shaft 4223 is inserted. A hole near the base end of the arm portion of the upper arm 421 is aligned with this hole, and the pivot shaft 4211 is inserted, whereby the upper arm 421 is attached to the upright 41 so as to be able to swing freely.

[0023] 4B , the lower arm 422 is longer than the upper arm 421. When the upper arm 421 and the lower arm 422 are attached to the upright 41, the tip of the upper arm 421 does not reach the wheel 400 in a front view, but the tip of the lower arm 422 does reach the wheel 400. In other words, the tip of the lower arm 422 is located outward of the tip of the upper arm 421 in a front view.

[0024] 4B, the lower arm 422 has a connecting portion 4222 that connects the lower portions of the two arm portions 4221. The lower arm 422 is supported on the upright 41 via a pivot shaft 4223.

[0025] FIG. 5 is a perspective view showing the suspension assembly shown in FIGS. 3 and 4A-B when used for a front wheel and assembled to a vehicle body frame.

[0026] Holes are formed near both the left and right ends of the body frame 1, and bearings are fitted into these holes. The shaft 411 of the upright 41 is inserted through the inside of this bearing, so that the upright 41 is attached to the body frame 1 so as to be rotatable around the shaft 411. An actuator unit 50 is attached above the shaft 411. The actuator unit 50 incorporates an actuator and a locking mechanism, as well as a reducer and a rotary encoder, all built into one unit. The rotary encoder detects the orientation of the upright 41 (suspension unit 40). A lever 60 is fixed to the housing 51 of the actuator unit 50.

[0027] The actuator built into the actuator unit 50 is connected to the shaft 411 of the suspension unit 40 via a reducer. Therefore, when this actuator is activated, the shaft 411 rotates, and the suspension unit 40 rotates.

[0028] The locking mechanism restricts the rotation of the actuator's rotary shaft. In an unlocked state where the locking mechanism is not activated, the actuator's rotary shaft is freely rotatable. In a locked state where the locking mechanism is activated, the actuator's rotary shaft is integrated with the housing 51 of the actuator unit 50. Therefore, when the lever 60 is moved in this state, the shaft portion 411 rotates integrally with the housing 51 of the actuator unit 50, causing the suspension unit 40 to rotate. An electromagnetic brake is a suitable example of the locking mechanism. However, this is not limiting. For example, a mechanism that mechanically locks using gears or hydraulic pressure may also be used. Furthermore, a suitable electromagnetic brake is one that operates in a locked state when de-energized and is released to enter an unlocked state when energized.

[0029] A steering gear box 100 is attached to the vehicle body frame 1. A tie rod 110 extending from the steering gear box 100 is connected to the lever 60. Note that Fig. 4 shows the tie rod 110 with the tie rod end 112 detached from the tie rod shaft 111.

[0030] When the driver operates the steering wheel 12 while the locking mechanism of the suspension unit 40 is in the locked state, the lever 60 is moved in accordance with the amount of operation of the steering wheel 12. This causes the upright 41 to rotate around the shaft 411 as the center of rotation.

[0031] Fig. 6 is a perspective view showing a steering gear box, Fig. 7A is a plan view of the steering gear box, Fig. 7B is a cross-sectional view taken along line BB of Fig. 7A, and Fig. 7C is a cross-sectional view taken along line CC of Fig. 7A.

[0032] The steering gearbox 100 is a rack-and-pinion type in which a pinion gear 103 meshes with a rack bar 102 housed in a rack case 101. The pinion gear 103 is longer than the diameter of the rack case 101 and passes through the rack case 101. One end of the pinion gear 103 (the rear side in FIG. 6 , the upper side in FIG. 7A ) is connected to the steering column shaft 11. A locking mechanism unit 120 is attached to the other end of the pinion gear 103 (the front side in FIG. 6 , the lower side in FIG. 7A ). In an unlocked state in which a locking mechanism built into the locking mechanism unit 120 is not engaged, the pinion gear 103 is freely rotatable. In a locked state in which a locking mechanism built into the locking mechanism unit 120 is engaged, the pinion gear 103 is fixed and the rack bar 102 does not move. An electromagnetic brake is a suitable example of a locking mechanism built into the locking mechanism unit 120, but this is not limiting. For example, it may be a type that is locked mechanically using gears or hydraulically. Also, the electromagnetic brake is preferably a type that operates to a locked state when energized and is released to an unlocked state when de-energized.

[0033] Here, the rear wheel suspension assemblies will also be described. The basic structure of the rear wheel suspension assemblies 230, 240 is the same as that of the front wheel suspension assemblies 210, 220, as shown in FIGS. 3 and 4 . As shown in FIG. 1 , bearings are fitted into holes formed near both the left and right rear ends of the body frame 1, and the upright 41 is assembled to the body frame 1 by inserting the axle 411 of the upright 41 through the inside of the bearing. Assembled in this manner, the upright 41 (suspension unit) is rotatable around the axle 411. Similar to the front wheel suspension assemblies 210, 220, an actuator unit 50 is assembled above the axle 411. The actuator unit 50 incorporates an actuator and a locking mechanism, as well as a reducer and a rotary encoder. The rear wheel suspension assemblies 230, 240 differ from the front wheel suspension assemblies 210, 220 in that the lever 60 does not have to be fixed to the housing 51 of the actuator unit 50. However, the same unit as that for the front wheels may be used, that is, an actuator unit 50 with the lever 60 fixed to the housing 51 may be used. Furthermore, the wheel mounting body 43 of the suspension unit 40 does not have to have a built-in motor that drives the wheels 400. If only the wheel mounting body 43 of the front wheel suspension unit 40 has a built-in motor, the vehicle can be made into a front-wheel drive vehicle.

[0034] 8 is a diagram showing a steering system centered around a controller. The steering system 10 includes a steering gear box 100 connected to a controller 90 via a signal line, a right front wheel suspension assembly 210, a left front wheel suspension assembly 220, a right rear wheel suspension assembly 230, a left rear wheel suspension assembly 240, and an operation touch panel 70.

[0035] FIG. 9 is a diagram showing an operation touch panel. The operation touch panel 70 displays shift positions "P," "R," "N," and "D." The currently selected shift position is highlighted by a frame. In FIG. 9, the shift position "P" is selected. Special drive modes are displayed below the shift positions. "Rotate mode," "Slanting mode," "Small turn mode," and "Parallel mode" are displayed.

[0036] 10 is a flowchart of the process executed by the controller in the normal driving mode. When the driver does not operate the operation touch panel 70 in any particular way, i.e., when the special drive mode is not selected, the normal driving mode is selected.

[0037] In the normal running mode, as shown in FIG. 10, in step S11, the controller locks the locking mechanisms of the front and rear wheel suspension assemblies when the front and rear wheels are in a neutral position in a straight-ahead state (a state in which the wheels are facing in the fore-and-aft direction of the vehicle).

[0038] In step S12, the controller puts the locking mechanism of the steering gear box 100 into an unlocked state.

[0039] 11 is a diagram showing the state of the wheels in the normal driving mode. When the controller controls the wheels as described above, the wheels (suspension units) are in a neutral state in which the front and rear wheels are oriented in the straight-ahead direction of the vehicle.

[0040] In this state, if the driver depresses the accelerator pedal with the steering wheel 12 in the straight ahead position (neutral position) at shift position "D," the vehicle will move forward in a straight line. If the driver depresses the accelerator pedal with the steering wheel 12 in the straight ahead position (neutral position) at shift position "R," the vehicle will move backward in a straight line. When the driver operates the steering wheel 12, the lever 60 is moved according to the amount of operation, and the front wheel suspension unit rotates around the axle 411 as the rotation center, changing the steering angle of the right front wheel and the left front wheel. When the driver turns the steering wheel 12 to the right, the front wheels are steered to the right, as shown in FIG. 11 .

[0041] (Rotate mode) FIG. 12 is a diagram showing the operation touch panel in the rotate mode. When the shift position "P" is selected, it becomes possible to select a special drive mode. When the driver selects the "rotate mode", an operation area 71 is displayed on the operation touch panel 70, and as shown in FIG. 12, it is displayed that the mode is the "rotate mode".

[0042] FIG. 13 is a flow chart showing the operations performed by the controller in the rotate on the spot mode.

[0043] In the rotate on the spot mode, as shown in FIG. 13 , in step S21, the controller locks the locking mechanism of the steering gear box 100 when the steering gear box 100 is in the neutral position. This fixes the pinion gear. Note that, to place the steering gear box 100 in the neutral position, for example, a command sound may be emitted to the driver or a command lamp may be turned on / off to instruct the driver to move the steering wheel to the neutral position. Alternatively, the position of the rack bar 102 may be adjusted by the power steering device.

[0044] In step S22, the controller unlocks the locking mechanisms of the front and rear wheel suspension assemblies, steers the right front wheel to the left, steers the left front wheel to the right, steers the right rear wheel in the same direction as the left front wheel, and steers the left rear wheel in the same direction as the right front wheel.

[0045] Figure 14 is a diagram showing the state of the wheels in the rotate on the spot mode. When controlled by the controller as described above, the wheels (suspension units) become as shown in Figure 14. That is, the right front wheel is steered to the left by a predetermined angle relative to the straight-ahead state, the left front wheel is steered to the right by a predetermined angle relative to the straight-ahead state, the right rear wheel is steered to the same direction as the left front wheel by a predetermined angle relative to the straight-ahead state, and the left rear wheel is steered to the same direction as the right front wheel by a predetermined angle relative to the straight-ahead state.

[0046] In this state, if the driver traces his / her finger clockwise on the operation area 71 of the operation touch panel 70 shown in Fig. 12, the vehicle will turn right on the spot as shown by the dashed line in Fig. 14. If the driver traces his / her finger counterclockwise on the operation area 71 of the operation touch panel 70, the vehicle will turn left on the spot as shown by the dashed line in Fig. 14.

[0047] (Side-by-side traveling (parallel) mode 1) Fig. 15 is a diagram showing the operation touch panel in the side-by-side traveling (parallel) mode. When the driver selects the "side-by-side traveling (parallel) mode," an operation area 71 is displayed on the operation touch panel 70, and as shown in Fig. 15, it is displayed that the mode is the "side-by-side traveling (parallel) mode."

[0048] FIG. 16 is a flowchart showing the operations executed by the controller in parallel mode 1.

[0049] In the lateral running (parallel) mode 1, as shown in FIG. 16 , in step S31, the controller locks the locking mechanism of the steering gear box 100 when the steering gear box 100 is in the neutral position. This fixes the pinion gear. Note that, to place the steering gear box 100 in the neutral position, for example, a command sound may be emitted to the driver or a command lamp may be turned on / off to instruct the driver to move the steering wheel to the neutral position. Alternatively, the position of the rack bar 102 may be adjusted by the power steering device.

[0050] In step S32, the controller unlocks the locking mechanisms of the front and rear wheel suspension assemblies and steers the front and rear wheels so that they face straight sideways.

[0051] Figure 17 is a diagram showing the state of the wheels in lateral running (parallel) mode 1. When controlled by the controller as described above, the wheels (suspension units) become as shown in Figure 17. That is, the right front wheel is steered approximately 90 degrees to the left with respect to the straight-ahead state and is in a lateral position, the left front wheel is steered approximately 90 degrees to the right with respect to the straight-ahead state and is in a lateral position, the right rear wheel is steered approximately 90 degrees in the same direction as the left front wheel with respect to the straight-ahead state and is in a lateral position, and the left rear wheel is steered approximately 90 degrees in the same direction as the right front wheel with respect to the straight-ahead state and is in a lateral position.

[0052] In this state, if the driver traces his / her finger from left to right on the operation area 71 of the operation touch panel 70 shown in Fig. 15, the vehicle will travel straight to the right. If the driver traces his / her finger from right to left on the operation area 71 of the operation touch panel 70, the vehicle will travel straight to the left.

[0053] In the case of a four-wheel drive type in which motors are built into both the wheel mounting body 43 of the front wheel suspension unit 40 and the wheel mounting body 43 of the rear wheel suspension unit 40, the front and rear wheels are turned approximately 90 degrees from the straight-ahead position to a straight-side position, and equal driving force is generated in all four wheels, making it possible to travel straight-sideways.

[0054] On the other hand, in the case of a front-wheel drive vehicle in which a motor is built only in the wheel mounting body 43 of the front-wheel suspension unit 40, a driving force can be generated in the front wheels (drive wheels), but not in the rear wheels (passive wheels). Therefore, when the rear wheels are steered at the same angle as the front wheels and a driving force F is generated in the front wheels (drive wheels), running resistance R is generated in the front wheels (drive wheels) and rear wheels (passive wheels), as shown in FIG. 18A. Then, as shown in FIG. 18B, the front wheels (drive wheels) lead and the rear wheels (passive wheels) lag, causing rotation around the rear wheels (passive wheels), resulting in movement as shown in FIG. 18C, making it impossible to travel sideways. Therefore, by appropriately adjusting the steering angle of the rear wheels (passive wheels), sideways travel becomes possible. In the case of a rear-wheel drive type in which a motor is built only in the wheel mounting body 43 of the rear wheel suspension unit 40, the rear wheels (drive wheels) will move ahead and the vehicle will not be able to travel sideways, so by appropriately adjusting the steering angle of the front wheels (passive wheels), the vehicle will be able to travel sideways.

[0055] (Parallel driving mode 2)

[0056] FIG. 19 is a flowchart showing the operations executed by the controller in parallel mode 2.

[0057] In the parallel driving mode 1, the vehicle is a four-wheel drive type or a two-wheel drive type (front-wheel drive type / rear-wheel drive type). In contrast, in the parallel driving mode 2, the vehicle is a two-wheel drive type (front-wheel drive type / rear-wheel drive type). In particular, the following description will be given for a front-wheel drive type in which the front wheels are drive wheels and the rear wheels are passive wheels.

[0058] In the parallel running mode 2, as shown in FIG. 19 , in step S310, the controller locks the locking mechanism of the steering gear box 100 when the steering gear box 100 is in the neutral position. This fixes the pinion gear. To place the steering gear box 100 in the neutral position, for example, the controller may issue a command sound to the driver or turn on / off a command lamp to instruct the driver to move the steering wheel to the neutral position. Alternatively, the position of the rack bar 102 may be adjusted by the power steering device.

[0059] In step S320, the controller unlocks the locking mechanisms of the front and rear wheel suspension assemblies and steers the front wheels beyond 90 degrees relative to a straight-ahead state. Depending on the vehicle specifications, the steering angle may exceed 90 degrees by several degrees. In this way, the farther the right and left front wheels are from the vehicle centerline, the more forward the vehicle they will be. The rear wheels are also steered approximately 90 degrees relative to a straight-ahead state. Depending on the vehicle specifications, the steering angle may be several degrees short of 90 degrees, where the rear wheels would be directly to the side, or to 90 degrees, where the rear wheels would be directly to the side. In this way, the farther the right and left rear wheels are from the vehicle centerline, the more forward the vehicle they will be or the more they will be directly to the side.

[0060] 20A-20C are diagrams showing the state of the wheels when the lateral running (parallel) mode 2 is executed. When controlled by the controller as described above, the wheels (suspension units) that were initially in a straight-ahead state as shown in FIG. 20A are changed as follows. That is, as shown in FIG. 20B, the right front wheel is steered to the left relative to the straight-ahead state, the left front wheel is steered to the right relative to the straight-ahead state, the right rear wheel is steered in the same direction as the left front wheel relative to the straight-ahead state, and the left rear wheel is steered in the same direction as the right front wheel relative to the straight-ahead state. Furthermore, as shown in FIG. 20C, the right front wheel is steered to the left by several degrees more than 90 degrees relative to the straight-ahead state, and the left front wheel is steered to the right by several degrees more than 90 degrees relative to the straight-ahead state. That is, the farther the right front wheel and left front wheel are from the vehicle center line CL, the more they are positioned toward the front of the vehicle. Furthermore, the right rear wheel is steered in the same direction as the left front wheel by a few degrees or approximately 90 degrees from the straight-ahead state, and the left rear wheel is steered in the same direction as the right front wheel by a few degrees or approximately 90 degrees from the straight-ahead state. In other words, the farther the right rear wheel and the left rear wheel are from the vehicle center line CL, the more they are positioned toward the front of the vehicle or point directly to the side. Note that in Figure 20C, for ease of understanding, the wheels are shown in a deformed state where they are steered from the directly to the side position by a greater angle than the actual steering angle.

[0061] In this state, if the driver traces his / her finger from left to right on the operation area 71 of the operation touch panel 70 shown in FIG. 15 , as shown in FIG. 21A , a driving force F in the upper right direction and running resistance R in the lower left direction are generated in the right front wheel (drive wheel). A driving force F in the lower right direction and running resistance R in the upper left direction are generated in the left front wheel (drive wheel). A running resistance R in the lower left direction is generated in the right rear wheel (drive wheel). A running resistance R in the upper left direction is generated in the left rear wheel (drive wheel). These driving forces F and running resistance R are balanced, causing the vehicle to travel straight to the right, as shown in FIG. 21B → FIG. 21C . When the driver traces his / her finger from right to left on the operation area 71 of the operation touch panel 70, the right front wheel (drive wheel) and the left front wheel (drive wheel) rotate in the opposite direction to when the vehicle travels straight to the right, causing the vehicle to travel straight to the left.

[0062] (Slanting Mode) FIG. 22 is a flowchart showing the operations executed by the controller in slanting mode.

[0063] In the slanting mode, as shown in FIG. 22, in step S41, the controller locks the locking mechanism of the front wheel suspension assembly when the front wheel is in the neutral position for straight ahead driving.

[0064] In step S42, the controller unlocks the locking mechanism of the steering gear box 100.

[0065] In step S43, the controller unlocks the locking mechanism of the rear wheel suspension assembly and steers the rear wheels in the same direction as the front wheels in accordance with the driver's steering wheel operation amount (the steering amount of the steering gear box).

[0066] FIG. 23 shows the state of the wheels in slanting mode. When the controller controls the wheels (suspension units) as described above, the wheels are as shown in FIG. 23 . That is, the front wheels are steered by the driver's steering wheel operation. The rear wheels are steered in the same direction as the front wheels by the actuator of the rear wheel suspension unit in accordance with the driver's steering wheel operation. In the case of a four-wheel drive vehicle in which motors are built into both the wheel mounting bodies 43 of the front wheel suspension units 40 and the wheel mounting bodies 43 of the rear wheel suspension units 40, equal driving force can be generated for all four wheels, making slanting possible by steering the rear wheels in the same manner as the front wheels. In the case of a front-wheel drive vehicle in which a motor is built only into the wheel mounting bodies 43 of the front wheel suspension units 40, driving force can be generated for the front wheels but not for the rear wheels. Therefore, if the rear wheels are steered at the same angle as the front wheels, the front wheels will lead and the rear wheels will lag, making slanting impossible. Therefore, by appropriately adjusting the steering angle of the rear wheels, it becomes possible to drive diagonally.

[0067] (Small Turn Mode) FIG. 24 is a flowchart that the controller executes in the small turn mode.

[0068] In the small turn mode, as shown in FIG. 24, in step S51, the controller locks the locking mechanism of the front wheel suspension assembly when the front wheel is in the neutral position for straight driving.

[0069] In step S52, the controller puts the locking mechanism of the steering gear box 100 into an unlocked state.

[0070] In step S53, the controller unlocks the locking mechanism of the rear wheel suspension assembly and steers the rear wheels in the opposite direction to the front wheels in accordance with the driver's steering wheel operation amount (the steering amount of the steering gear box).

[0071] FIG. 25 is a diagram showing the state of the wheels in small turn mode. When the controller controls as described above, the wheels (suspension units) become as shown in FIG. 25. That is, the front wheels are steered by the driver's steering wheel operation. The rear wheels are steered in the opposite direction to the front wheels by the actuator of the rear wheel suspension unit in accordance with the amount of steering wheel operation by the driver. The right rear wheel is steered in the opposite direction at an angle approximately equal to the steering angle of the right front wheel relative to the neutral position. The left rear wheel is steered in the opposite direction at an angle approximately equal to the steering angle of the left front wheel relative to the neutral position.

[0072] According to this embodiment, the suspension is unitized and the suspension unit is assembled to the body frame 1 by inserting the shaft portion 411 of the suspension unit into a hole in the body frame 1, which makes assembly easy and provides excellent productivity. Some suspension units have a built-in motor, while others do not, but the basic configuration is the same, which provides excellent mass productivity.

[0073] An electromagnetic brake is suitable as a locking mechanism for a suspension assembly. It is also suitable as a locking mechanism for a steering gear box because it is small, lightweight, and easy to control.

[0074] The electromagnetic brake used in the suspension assembly is preferably a type that operates to a locked state when de-energized and is released to an unlocked state when energized.The electromagnetic brake used in the steering gearbox is preferably a type that operates to a locked state when energized and is released to an unlocked state when de-energized.In this way, in the normal driving mode, both the electromagnetic brake used in the suspension assembly and the electromagnetic brake used in the steering gearbox are de-energized.The normal driving mode lasts for a longer period of time than the special driving mode, which leads to energy savings.

[0075] In rotate mode and parallel driving mode, the driver moves the vehicle by tracing their finger over the operation area of ​​the operation touch panel. Since rotate and parallel driving are not common movements, the driver may feel uncomfortable using the steering wheel, but by tracing their finger over the operation area of ​​the operation touch panel, the operation is easy for the driver to understand.

[0076] Although the embodiments of the present invention have been described above, the above embodiments merely illustrate some of the application examples of the present invention, and it is not intended that the technical scope of the present invention be limited to the specific configurations of the above embodiments.

[0077] For example, although the above description has been given with reference to a double wishbone type suspension, the technical scope of the present invention is not intended to be limited to the double wishbone type and may be applied to other types such as strut types and multi-link types.

[0078] Furthermore, the specific shapes and sizes of the components shown in the drawings are merely examples and can be changed as appropriate.

[0079] The above embodiments can be combined as appropriate.

[0080] This application claims priority based on Japanese Patent Application No. 2023-173760 filed with the Japan Patent Office on October 5, 2023, and Japanese Patent Application No. 2023-198574 filed with the Japan Patent Office on November 22, 2023, the entire contents of which are incorporated herein by reference.

Claims

1. A steering gear box having: a rack case; a rack bar housed in said rack case; a pinion gear that is longer than the diameter of said rack case, passes through said rack case, and meshes with said rack bar, with one end connected to a steering column shaft; and a locking mechanism that is attached to the other end of said pinion gear, and that allows said pinion gear to rotate freely in an unlocked state when not activated, and fixes said pinion gear so as not to rotate in a locked state when activated.

2. A steering gear box according to claim 1, wherein the locking mechanism is an electromagnetic brake which is in an unlocked state in a de-energized state and which is activated to be in a locked state in a powered-on state.

3. A suspension assembly comprising: a suspension unit; and an actuator unit, wherein the suspension unit comprises: a base member having an axle portion standing upright on a top surface, the axle portion being inserted into a hole in the body frame and attached to the body frame; a suspension arm attached to the base member so as to be able to swing; and a wheel mounting body to which a wheel can be attached and which is attached to the suspension arm, wherein the actuator unit is attached above the axle portion of the base member, and comprises: a housing; an actuator housed inside the housing and capable of driving the axle portion of the base member by rotating its rotating shaft; a locking mechanism housed inside the housing and allowing the rotating shaft of the actuator to rotate freely in an unlocked state when not activated, and allowing the rotating shaft of the actuator to rotate integrally with the housing in a locked state when activated; and a lever fixed to the housing and to which a tie rod of a steering gear box is connected.

4. A suspension assembly as claimed in claim 3, wherein the locking mechanism is an electromagnetic brake which operates in a de-energised state to be in a locked state and which is released in a powered state to be in an unlocked state.

5. A steering system having a steering gear box, a right front wheel suspension assembly, a left front wheel suspension assembly, a right rear wheel suspension assembly, and a left rear wheel suspension assembly, wherein the steering gear box comprises: a rack case, a rack bar housed in the rack case, a pinion gear that is longer than the diameter of the rack case, passes through the rack case, meshes with the rack bar, and has one end connected to a steering column shaft, and a lock mechanism that is attached to the other end of the pinion gear, and allows the pinion gear to rotate freely in an unlocked state when not activated, and fixes the pinion gear so as not to rotate in an activated locked state, wherein the right front wheel suspension assembly comprises: a right front wheel suspension unit, and a right front wheel actuator unit, and the right front wheel suspension unit comprises: a right front wheel base member having a right front wheel axle standing upright on a top surface, the right front wheel axle being inserted into a hole in the body frame and attached to the body frame; a right front wheel suspension arm attached to the right front wheel base member so as to be able to swing; and a right front wheel mounting body to which a wheel can be attached and which is attached to the right front wheel suspension arm, wherein the right front wheel actuator unit is attached above the right front wheel axle of the right front wheel base member, and comprises: a right front wheel housing; a right front wheel actuator housed inside the right front wheel housing and capable of driving the right front wheel axle of the right front wheel base member by rotation of a rotating shaft; a right front wheel lock mechanism housed inside the right front wheel housing and which allows the rotating shaft of the right front wheel actuator to rotate freely in an unlocked state when not activated, and allows the rotating shaft of the right front wheel actuator to rotate integrally with the right front wheel housing in an activated locked state; a right front wheel lever fixed to the right front wheel housing and connected to a tie rod of a steering gear box, and the left front wheel suspension assembly comprises: a left front wheel suspension unit;and a left front wheel actuator unit, wherein the left front wheel suspension unit comprises: a left front wheel base member having a left front wheel axle standing upright on a top surface, the left front wheel axle being inserted into a hole in the body frame and attached to the body frame, a left front wheel suspension arm attached to the left front wheel base member so as to be able to swingably move, and a left front wheel mounting body to which a wheel can be attached and which is attached to the left front wheel suspension arm, wherein the left front wheel actuator unit comprises: a left front wheel housing attached above the left front wheel axle of the left front wheel base member; and a left front wheel actuator housed inside the left front wheel housing and capable of driving the left front wheel axle of the left front wheel base member by rotation of a rotating shaft, the left front wheel lock mechanism is housed inside the left front wheel housing and in an unlocked state when not in operation allows the rotation shaft of the left front wheel actuator to rotate freely, and in a locked state when in operation allows the rotation shaft of the left front wheel actuator to rotate integrally with the left front wheel housing; and a left front wheel lever fixed to the left front wheel housing and to which a tie rod of a steering gear box is connected; the right rear wheel suspension assembly has: a right rear wheel suspension unit; and a right rear wheel actuator unit; the right rear wheel suspension unit comprises: a right rear wheel base member having a right rear wheel axle portion standing upright on a top surface, the right rear wheel axle portion being inserted into a hole in the body frame and attached to the body frame; a right rear wheel suspension arm attached to the right rear wheel base member so as to be able to swing; and a right rear wheel mounting body to which a wheel can be attached and which is assembled to the right rear wheel suspension arm; a right rear wheel housing mounted above the right rear wheel axle of the right rear wheel base member; a right rear wheel actuator housed inside the right rear wheel housing and capable of driving the right rear wheel axle of the right rear wheel base member by rotation of a rotary shaft;and a right rear wheel lock mechanism housed inside the right rear wheel housing, which allows the rotation shaft of the right rear wheel actuator to rotate freely in an unlocked state when it is not activated, and allows the rotation shaft of the right rear wheel actuator to rotate integrally with the right rear wheel housing when it is activated and locked; the left rear wheel suspension assembly has: a left rear wheel suspension unit; and a left rear wheel actuator unit; the left rear wheel suspension unit comprises: a left rear wheel base member having a left rear wheel axle portion standing upright on a top surface, the left rear wheel axle portion being inserted into a hole in the body frame and attached to the body frame; a left rear wheel suspension arm attached to the left rear wheel base member so as to be able to swingably mount a wheel; and a left rear wheel mounting body attached to the left rear wheel suspension arm; the left rear wheel actuator unit is attached above the left rear wheel axle portion of the left rear wheel base member, A steering system comprising: a left rear wheel actuator housed inside the left rear wheel housing and capable of driving a left rear wheel axle portion of the left rear wheel base member by rotation of a rotating shaft; and a left rear wheel locking mechanism housed inside the left rear wheel housing and allowing the rotating shaft of the left rear wheel actuator to rotate freely in an unlocked state where it is not activated, and allowing the rotating shaft of the left rear wheel actuator to rotate integrally with the left rear wheel housing in a locked state where it is activated.

6. A steering system as claimed in claim 5, wherein in a normal driving mode, the locking mechanism of the steering gear box is unlocked, the right front wheel locking mechanism of the right front wheel suspension unit is locked when the right front wheel is in a neutral position, the left front wheel locking mechanism of the left front wheel suspension unit is locked when the left front wheel is in a neutral position, the right rear wheel locking mechanism of the right rear wheel suspension unit is locked when the right rear wheel is in a neutral position, and the left rear wheel locking mechanism of the left rear wheel suspension unit is locked when the left rear wheel is in a neutral position.

7. A steering system as claimed in claim 5, wherein in a turn-on-the-spot mode, the locking mechanism of the steering gearbox is locked when the steering gearbox is in a neutral position, the right front wheel locking mechanism of the right front wheel suspension unit is unlocked and the right front wheel is steered to the left by the right front wheel actuator, the left front wheel locking mechanism of the left front wheel suspension unit is unlocked and the left front wheel is steered to the right by the left front wheel actuator, the right rear wheel locking mechanism of the right rear wheel suspension unit is unlocked and the right rear wheel is steered in the same direction as the left front wheel by the right rear wheel actuator, and the left rear wheel locking mechanism of the left rear wheel suspension unit is unlocked and the left rear wheel is steered in the same direction as the right front wheel by the left rear wheel actuator.

8. A steering system according to claim 7, wherein in the on-the-spot turning mode, the vehicle is turned in the same direction as the driver traces his / her finger on the operation area of ​​the operation touch panel.

9. A steering system as claimed in claim 5, wherein in a straight sideways driving mode, the locking mechanism of the steering gear box is locked when the steering gear box is in a neutral position, the right front wheel locking mechanism of the right front wheel suspension unit is unlocked and the right front wheel is steered by the right front wheel actuator to face straight sideways, the left front wheel locking mechanism of the left front wheel suspension unit is unlocked and the left front wheel is steered by the left front wheel actuator to face straight sideways, the right rear wheel locking mechanism of the right rear wheel suspension unit is unlocked and the right rear wheel is steered by the right rear wheel actuator to face straight sideways, and the left rear wheel locking mechanism of the left rear wheel suspension unit is unlocked and the left rear wheel is steered by the left rear wheel actuator to face straight sideways.

10. A steering system as claimed in claim 5, wherein in a straight side running mode, the locking mechanism of the steering gear box is locked when the steering gear box is in a neutral position, the right front wheel locking mechanism of the right front wheel suspension unit is unlocked and the right front wheel actuator is used to steer the right front wheel so that a portion thereof is positioned further forward from the vehicle center line, the left front wheel locking mechanism of the left front wheel suspension unit is unlocked and the left front wheel actuator is used to steer the left front wheel so that a portion thereof is positioned further forward from the vehicle center line, the right rear wheel locking mechanism of the right rear wheel suspension unit is unlocked and the right rear wheel actuator is used to steer the right rear wheel so that it faces straight sideways, and the left rear wheel locking mechanism of the left rear wheel suspension unit is unlocked and the left rear wheel actuator is used to steer the left rear wheel so that it faces straight sideways.

11. A steering system as claimed in claim 5, wherein in a lateral travel mode, the locking mechanism of the steering gearbox is locked when the steering gearbox is in a neutral position, the right front wheel locking mechanism of the right front wheel suspension unit is unlocked and the right front wheel actuator is used to steer the right front wheel so that a portion thereof is positioned further forward from the vehicle center line, the left front wheel locking mechanism of the left front wheel suspension unit is unlocked and the left front wheel actuator is used to steer the left front wheel so that a portion thereof is positioned further forward from the vehicle center line, the right rear wheel locking mechanism of the right rear wheel suspension unit is unlocked and the right rear wheel actuator is used to steer the right rear wheel so that a portion thereof is positioned further forward from the vehicle center line, and the left rear wheel locking mechanism of the left rear wheel suspension unit is unlocked and the left rear wheel actuator is used to steer the left rear wheel so that a portion thereof is positioned further forward from the vehicle center line.

12. A steering system according to any one of claims 9 to 11, wherein in a lateral driving mode, the vehicle is driven lateral in the same direction as the driver traces his / her finger on the operation area of ​​the operation touch panel.

13. A steering system as claimed in claim 5, wherein in a diagonal travel mode, the locking mechanism of the steering gearbox is unlocked, the right front wheel locking mechanism of the right front wheel suspension unit is locked when the right front wheel is in a neutral position, the left front wheel locking mechanism of the left front wheel suspension unit is locked when the left front wheel is in a neutral position, the right rear wheel locking mechanism of the right rear wheel suspension unit is unlocked, and the right rear wheel is steered by the right rear wheel actuator in the same direction as the right front wheel and the left front wheel in accordance with the steering amount of the steering gearbox, and the left rear wheel locking mechanism of the left rear wheel suspension unit is unlocked, and the left rear wheel is steered by the left rear wheel actuator in the same direction as the right front wheel and the left front wheel in accordance with the steering amount of the steering gearbox.

14. A steering system as claimed in claim 5, wherein in a tight turning driving mode, the locking mechanism of the steering gearbox is unlocked, a right front wheel locking mechanism of the right front wheel suspension unit is locked when the right front wheel is in a neutral position, a left front wheel locking mechanism of the left front wheel suspension unit is locked when the left front wheel is in a neutral position, a right rear wheel locking mechanism of the right rear wheel suspension unit is unlocked, and the right rear wheel is turned by the right rear wheel actuator in the opposite direction to the right front wheel and the left front wheel in accordance with the steering amount of the steering gearbox, and a left rear wheel locking mechanism of the left rear wheel suspension unit is unlocked, and the left rear wheel is turned by the left rear wheel actuator in the opposite direction to the right front wheel and the left front wheel in accordance with the steering amount of the steering gearbox.

Images