WO2016117585A1 - Steering apparatus - Google Patents

Abstract

A steering apparatus provided with: a pair of rack bars (53, 54) connected to tie rods (12, 22) of left and right wheels (w), respectively; a synchronous gear device (57) for converting movement of one rack bar (53) in the left/right direction to movement of the other rack bar (54) in the other left/right direction; a rack bar operating means (60) capable of moving the pair of rack bars (53, 54) in mutually opposite directions; a synchronous gear box (66) capable of retaining the synchronous gear device (57) and moving in the left/right direction; a rack case (50) for retaining the pair of rack bars (53, 54), the rack case (50) being fixed to a frame side of a vehicle (1); and a pair of fixing mechanisms (80) retained by the rack case (50) and arranged at both ends of the synchronous gear box (66).

Description

Steering device

This invention relates to a steering device that steers wheels.

A steering mechanism called Ackermann-Jantou type that steers the wheels using a steering link mechanism that connects the left and right wheels (hereinafter collectively referred to as "wheels" including tires, wheels, hubs, etc.) There is. This steering mechanism uses a tie rod and a knuckle arm so that the left and right wheels have the same turning center when the vehicle turns.

As this steering mechanism, for example, there is a configuration shown in Patent Document 1 below. This steering mechanism has a steering link mechanism for left and right wheels using a tie rod and a knuckle arm on at least one of the front wheel side and the rear wheel side, and the tie rod length, the distance between the left and right tie rods, or each wheel and the knuckle arm. By providing an actuator that changes any one of the angles formed, normal travel, parallel movement, and all of the small travels can be performed smoothly.

The steering mechanism shown in the following Patent Document 2 is disposed between the left and right wheels of the front and rear wheels, and can rotate around the axis, and the rotation of the divided steering shaft between the left and right divided steering shafts. Forward / reverse switching means for switching the direction between forward and reverse directions is provided. This switching means enables a steering angle of 90 degrees, lateral movement, and the like.

Patent Document 3 below discloses a technology of a four-wheel steered vehicle in which an actuator is operated in accordance with the steering of the front wheels to steer the rear wheels. Patent Document 4 below discloses a technique of a steering mechanism in which a toe adjustment of the left and right wheels is performed by moving a rack housing connecting the left and right wheels in the front-rear direction to improve running stability.

Japanese Patent Laid-Open No. 04-262971 JP 2007-22159 A Utility Model Registration No. 2600374 JP 2003-127876 A

According to a general Ackermann-Jantou-type steering link mechanism, during normal driving, a line extending vertically from the rotation line of each wheel (the center line in the width direction of the wheel) gathers at the turning center of the vehicle. Smooth running is possible. However, when the lateral movement of the vehicle (transverse movement in the lateral direction with the vehicle facing in the front-rear direction) is obtained, steering the wheel in a direction of 90 degrees with respect to the front-rear direction is a problem with the length of the steering link. It is difficult to interfere with other members. Further, even if one of the left and right wheels is steered at 90 degrees, the other wheel is not completely parallel to the one wheel, and smooth running is difficult.

With the technique described in Patent Document 1, it is possible to move the vehicle in the lateral direction, turn around, and the like. However, since an actuator for changing the length of the tie rod, the distance between the left and right tie rods, or the angle formed by the wheel and the knuckle arm is provided, the number of actuators is large and the control is complicated. In addition, the technique described in Patent Document 2 not only has a complicated structure due to its mechanism, but also uses a large number of gears to steer the wheels by the rotation of the rack bar. For this reason, rattling is likely to occur, and it is difficult to smoothly steer the wheels.

Further, the technology of Patent Document 3 is an example of a conventional four-wheel steering mechanism and enables rear wheel steering, but it is difficult to move laterally for the same reason described above only with this mechanism. Furthermore, while the technique of Patent Document 4 allows toe adjustment, it cannot cope with lateral movement of the vehicle, small turn, and the like.

Therefore, the present invention has an object to deal with special turning such as lateral movement and small turn without using a complicated mechanism in a vehicle that gives a steering angle to four wheels, and the amount of turning is accurately determined. It is an object to make it possible to control it.

In order to solve the above-described problems, the present invention includes a tie rod connected to the left and right wheels of a front wheel or a rear wheel and steering the left and right wheels, a pair of rack bars respectively connected to the tie rods of the left and right wheels, A synchronous gear device that meshes with a pair of rack bars, and converts the movement of one rack bar in one direction with respect to the parallel direction of the teeth of the rack to the movement of the other rack bar in the other direction; Rack bar operation means capable of moving in the opposite direction along the parallel direction of the rack teeth of the rack bar, a synchronous gear box that holds the synchronous gear device and is movable along the parallel direction, and A rack case that holds the pair of rack bars and is fixed to the vehicle frame; and a fixing mechanism that is held by the rack case. When moving in the opposite direction along the parallel direction, employing a steering apparatus characterized by restricting the movement of the said parallel direction of the synchronous gearbox by the fixing mechanism.

In this configuration, the fixing mechanism is a pair of fixing mechanisms arranged at both ends of the synchronous gear box, and the linear mechanism is the position of the synchronous gear box when the vehicle is traveling straight, and the fixing mechanism is A configuration in which a first fixed portion that restricts movement of the synchronous gearbox in one direction from the gearbox position when traveling straight and a second fixed portion that restricts movement of the synchronous gearbox in the other direction forms a pair. Can be adopted.

Further, when the synchronous gearbox is in a position shifted in one direction from the straight-running gearbox position, the first fixing portion is set to an unregulated state in which the movement of the synchronous gearbox is not restricted. When the synchronous gearbox reaches the linear gearbox position due to the movement of the synchronous gearbox in the other direction, the first fixed portion moves the synchronous gearbox in one direction from the linear gearbox position. The second fixing portion does not restrict the movement of the synchronous gear box when it is set to a restricting state to be restricted and the synchronous gear box is in a position shifted in a different direction from the gear box position during the straight traveling. It is set to the restricted state, and the synchronous gearbox is moved to the gearbox position when traveling straight by moving the synchronous gearbox in one direction from the state. Said second fixing portion when Tsu can adopt a configuration that is set in the restricted state to restrict movement of the synchronous gearbox from the straight running gearbox position the other direction.

Furthermore, it is possible to employ a configuration in which the first fixing portion and the second fixing portion are each provided with a detection mechanism that detects whether the restricted state or the unregulated state.

Due to the difference between the restricted state and the unrestricted state in the first fixed portion and the second fixed portion detected by the detection mechanism, the shift of the synchronous gear box from the position of the straight gearbox to the left and right is changed. It is possible to adopt a configuration provided with a deviation eliminating means for judging the presence / absence and the direction of deviation and moving the synchronous gear box toward the gear box position when traveling straight.

In each of these configurations, a configuration is adopted in which the movement of the synchronous gearbox by the fixing mechanism is restricted when the pair of rack bars are moved in opposite directions along the parallel direction of the rack teeth. be able to.

By connecting the wheels to the pair of rack bars that can be moved independently from each other via tie rods, the pair of rack bars can be fixed together in normal driving mode and operate without a sense of incongruity with conventional steering operations. By moving the pair of rack bars in different directions via the rack bar operating means and the synchronous gear device, various travel modes such as lateral movement and small turn can be realized. Further, by using a pair of rack bars that can be switched between separation and fixation, the cost can be reduced without using complicated mechanisms and controls. That is, in a vehicle that gives steering angles to four wheels, the front and rear wheels are steered to the same or opposite phase rudder angle without using a complicated mechanism, and special steering such as lateral movement and small turning is supported. Can do.

Furthermore, a rack case fixed to the vehicle frame and holding a pair of rack bars, a synchronous gear box that holds a synchronous gear device between the pair of rack bars and is movable in a parallel direction, and is held by the rack case. Since the pair of fixing mechanisms arranged at both ends of the synchronous gear box are provided, the movement of the synchronous gear box in the left-right direction can be restricted by the fixing mechanism when the pair of rack bars are moved in opposite directions. For this reason, even in harsh driving situations such as when a load is applied to one of the left and right wheels, the difference in the amount of movement of the pair of rack bars can be eliminated, and the front wheels or rear wheels are set to the opposite phase steering angle. When turning, the left and right turning amounts can be accurately controlled.

Image of vehicle using steering device of this embodiment Plan view showing a vehicle according to the present invention (general vehicle) Plan view showing a vehicle according to the present invention (steer-by-wire type vehicle) FIG. 2A is a plan view showing a normal driving mode (normal steering mode) in the vehicle of FIG. 2A. FIG. 2A is a plan view showing the small turn mode in the vehicle of FIG. 2A. FIG. 2A is a plan view showing an in-situ turn mode in the vehicle of FIG. 2A FIG. 2A is a plan view showing a lateral movement (parallel movement) mode in the vehicle of FIG. 2A. Sectional view showing the support state of the wheel The perspective view which shows the steering device which concerns on this invention The figure which shows the inside of a steering device when both fixing parts of a fixing mechanism are in a control state The figure which shows the inside of a steering device when one fixing | fixed part is in a regulation state and the other fixing | fixed part is in an unregulated state Side view of the separated state showing details of the rack bar operating means of the steering device Side view of the coupled state showing details of the rack bar operating means of the steering device Plan view showing the inside of the steering device Front view showing the inside of the steering device The top view which shows the inside of a steering device, and shows the state which a pair of rack bar approached The top view which shows the inside of a steering device and shows the state where a pair of rack bars are opened Bottom view showing a pair of rack bars and a synchronous gearbox in a steering device Side view of the locking mechanism as seen from the side with the lock pin FIG. 15A is a cross-sectional view taken along the line II in FIG. 15A showing the fixing mechanism and the lock pin retracted. FIG. 15A is a cross-sectional view taken along the line II in FIG. 15A showing the fixing mechanism and the lock pin protruding. Explanatory drawing showing the action of the fixing mechanism Explanatory drawing showing the action of the fixing mechanism

Embodiments of the present invention will be described with reference to the drawings. In the embodiment, the in-wheel motor M is mounted in the wheels of all the wheels w in the front, rear, left, and right sides of the vehicle 1. By providing the in-wheel motor M, various travel patterns are possible.

FIG. 1 shows an image diagram of a vehicle 1 using the steering device of the present invention. It shows a two-seater (side-by-side two-seat) vehicle body with ultra-compact mobility. The vehicle 1 can steer the wheels w through the steering shaft 3 by operating the steering 2. However, the present invention is not limited to ultra-compact mobility and can also be applied to ordinary vehicles.

2A and 2B are schematic plan views showing the drive system and control path of the vehicle 1. In this embodiment, the steering devices 10 and 20 of the present application are connected to the left and right wheels (FL and FR) of the front wheels and the left and right wheels (RL and RR) of the rear wheels via tie rods 12 and 22, respectively.

A steering device 10 for a front wheel according to the present application is a general vehicle (see FIG. 2A) provided with a steering shaft 3 or a steer-by-wire type vehicle (see FIG. 2B) provided with an actuator such as a motor that is operated by a rotating operation of the steering 2. ). In each example, normal steering can be performed by operating the pinion gear shaft linked to the steering device 10 for the front wheels.
Further, the steering device 20 for the rear wheels is operated by operating a pinion gear shaft linked to the steering device 20 for the rear wheels by an actuator (steer-by-wire) such as a motor that is operated by the rotation operation of the steering 2. Similarly, steering is possible. This rear-wheel steering device 20 can be employed in any type of vehicle shown in FIGS. 2A and 2B.

A vehicle equipped with the steering devices 10 and 20 of the present invention only on either the front wheels or the rear wheels can be adopted, or the steering device 20 of the present invention is equipped only on the rear wheels, and the front wheels are normal. A vehicle equipped with a general steering device can also be used.

The front and rear steering devices 10 and 20 are each provided with two rack bars for turning the left and right wheels w. Hereinafter, for both the front and rear wheels, the rack bar connected to the right wheel w with respect to the front-rear direction of the vehicle is the first rack bar 53, and the rack bar connected to the left wheel w is the second rack bar 54. Called. 2A and 2B, the direction indicated by the arrow on the left side of the page is the forward direction of the vehicle. The same applies to FIGS. 3 to 6 showing various operation modes.

The connecting members 11 and 21 of the rack bars 53 and 54 are connected to the left and right wheels w of the front wheel or the rear wheel via tie rods 12 and 22, respectively. Various members such as a knuckle arm are appropriately interposed between the tie rods 12 and 22 and the wheel w.

FIG. 7 shows a connection state between the wheel w in which the in-wheel motor M is accommodated and the tie rods 12 and 22. All the wheels w can be steered around a kingpin axis P formed by connecting the centers of the ball joints BJ provided at the tips of the upper arm UA and the lower arm LA supported by the frame of the vehicle 1, respectively. ing. In the in-wheel motor M, the motor unit 101, the speed reducer 102, and the wheel bearing 103 are arranged in series in this order from the inner side of the vehicle body toward the wheel w.

Embodiments of the steering devices 10 and 20 according to the present invention will be described. As shown in FIG. 8, the first rack bar 53 and the second rack bar 54 are rack cases (steering cylinders) 50 that extend in the left-right direction with respect to the straight traveling direction (front-rear direction) of the vehicle. Is held in. The rack case 50 includes a front cover 52 and a rear cover 51, and is directly or indirectly screwed to a frame (chassis) (not shown) of the vehicle 1 via a flange 50a.

Although not shown in the drawings, boots are provided for preventing foreign matter from entering the movable portion from the connecting portion between the tie rods 12 and 22 and the first rack bar 53 and the second rack bar 54 to the rack case 50. ing.

The steering devices 10 and 20 mesh with the first rack bar 53 and the second rack bar 54, respectively, and move the rack teeth of one rack bar in one direction with respect to the parallel direction of the rack teeth in the other direction of the other rack bar. The first rack bar 53 and the second rack bar 54 can be moved in the opposite direction along the parallel direction of the teeth of the respective racks through the synchronous gear device 57 for converting the movement into A possible rack bar operating means 60 and a synchronous gear box 66 that holds the synchronous gear device 57 and is movable along the parallel direction are provided. The synchronous gear box 66 is in a state in which it can move along the parallel direction of the rack teeth with respect to the rack case 50 immobile on the vehicle body 1.

Furthermore, the steering devices 10 and 20 include a pair of fixing mechanisms 80 that are held by the rack case 50 and arranged at both ends of the synchronous gear box 66.

The first rack bar 53 and the second rack bar 54 are, as shown in FIGS. 2A and 2B, the normal steering actuator 31 that is directly based on the operation of the steering 2 performed by the driver or interlocked with the operation of the steering 2. By this operation, it can be moved by the same distance in the same direction in the left-right direction. By this movement, the left and right wheels w are steered in the same direction in the left and right during normal travel. In this embodiment, the driving force of the normal steering actuator 31 that operates based on the operation of the steering 2 is input to the steering input shaft 33 (see FIG. 8) of the steering devices 10 and 20 as a rotational force. The steering input shaft 33 is connected to the steering shaft 3 via a steering joint (not shown).

Further, the steering devices 10 and 20 include rack bar operation means 60 as shown in FIGS. 8, 9A, and 9B. The rack bar operating means 60 is operated by the mode switching actuator 32 (see FIGS. 2A and 2B), and is the left-right direction with respect to the straight traveling direction of the vehicle 1, that is, the direction in which the rack expands / contracts The first rack bar 53 and the second rack bar 54 have a function of moving the same distance in opposite directions (in opposite directions) along the same distance.

As shown in FIGS. 11 and 12, the synchronization gear device 57 is a rack gear of the pair of rack bars 53, 54 facing each other, that is, for synchronizing the synchronization rack gear 53 a of the first rack bar 53 and the second rack bar 54. First synchronization gears 55 that mesh with the rack gears 54a are provided.

The first synchronization gear 55 includes three gears 55a, 55b, and 55c that are arranged in parallel at regular intervals along the parallel direction of the rack teeth of the first rack bar 53 and the second rack bar 54. When the first rack bar 53 is moved in one direction with respect to the parallel direction of the teeth of the first rack bar 53 by the driving force input from the rack bar operating means 60, the movement of the first rack bar 53 is different from that of the second rack bar 54. Converted to movement in the direction. Further, the amount of movement of the second rack bar 54 in the other direction is usually the same as the amount of movement of the first rack bar 53 in the one direction.

Note that gears 56 a and 56 b constituting the second synchronization gear 56 are arranged between the adjacent gears 55 a and 55 b of the first synchronization gear 55 and between the gears 55 b and 55 c, respectively. As shown in FIG. 12, the second synchronization gear 56 does not mesh with the synchronization rack gear 53 a of the first rack bar 53 or the synchronization rack gear 54 a of the second rack bar 54, and meshes only with the first synchronization gear 55. . The second synchronization gear 56 is for moving the three gears 55a, 55b, 55c of the first synchronization gear 55 in the same direction by the same angle. By the second synchronization gear 56, the first rack bar 53 and the second rack bar 54 can be smoothly moved relative to each other.

The synchronous gear device 57 including the first synchronous gear 55 and the second synchronous gear 56 is housed in a synchronous gear box 66. The rotation shafts of the first synchronization gear 55 and the second synchronization gear 56 are held in a synchronization gear box 66.

Further, as shown in FIGS. 8, 9A, and 9B, the first rack bar 53 and the second rack bar 54 include steering rack gears 53b and 54b, respectively, in addition to the synchronization rack gears 53a and 54a. . The synchronizing rack gears 53a and 54a may be formed of a member integrated with the steering rack gears 53b and 54b, or may be formed as separate members and fixed integrally by a fixing means such as a bolt.

When the first rack bar 53 is moved from the state shown in FIG. 13A to the state shown in FIG. 13B by the input of the driving force from the rack bar operating means 60, the first synchronization gear 55 is connected to the second rack bar 54. The force is transmitted via (55a, 55b, 55c), and the second rack bar 54 similarly moves from the state shown in FIG. 13A to the state shown in FIG. 13B. During this movement, the coupling mechanism 63 (described later) provided in the rack bar operation means 60 is in a separated state as shown in FIG. 10A, and the turning angle of the wheel w is relative to the vehicle longitudinal direction. After a predetermined angle (90 degrees in the state where the rack bars 53 and 54 are shown in FIG. 13B), the connecting mechanism 63 is connected as shown in FIG. 10B. In this connected state, the rack bars 53 and 54 are integrally moved by the same distance in the same direction in the left-right direction by the operation of the steering 2. 13A and 13B are views of FIG. 11 viewed from the opposite side.

Next, the operation of the rack bar operation means 60 will be described in detail.

The rack bar operation means 60 of the front wheel steering device 10 is driven through the steering input shaft 33 by the driving force of the normal steering actuator 31 that operates in conjunction with the rotation operation (see FIG. 1) of the steering 2 performed by the driver. Alternatively, rotation is transmitted to the first rotating shaft 61 provided in the rack bar operating means 60 by the driving force of the mode switching actuator 32 that operates in conjunction with the operation of the mode switching means 42 provided in the vehicle 1. Yes.

Similarly, the rack bar operation means 60 of the rear wheel steering device 20 is driven by the driving force of the normal steering actuator 31 that operates in conjunction with the rotational operation of the steering 2 performed by the driver, through the steering input shaft 33, or The rotation is transmitted to the first rotating shaft 61 provided in the rack bar operating means 60 by the driving force of the mode switching actuator 32 that operates in conjunction with the operation of the mode switching means 42 provided in the vehicle 1.

The rack bar operating means 60 includes a first pinion gear 62 attached to the first rotary shaft 61 so as to be integrally rotatable. The rack bar operation means 60 includes a second rotation shaft 64 arranged on the same straight line as the first rotation shaft 61 and a second pinion gear 65 attached to the second rotation shaft 64 so as to be integrally rotatable. .

10A and 10B, the first pinion gear 62 meshes with the steering rack gear 53b of the first rack bar 53, and the second pinion gear 65 meshes with the steering rack gear 54b of the second rack bar 54. It is like that.

Furthermore, the connecting mechanism 63 that can be coupled and separated from each other is provided between the first pinion gear 62 and the second pinion gear 65. The coupling mechanism 63 has a function of switching the first rotating shaft 61 and the second rotating shaft 64 between a state in which the first rotating shaft 61 and the second rotating shaft 64 can be relatively rotated (separated state (FIG. 10A)) and a state in which relative rotation is impossible (coupled state (FIG. 10B)).

The connecting mechanism 63 includes a moving part 63a provided on the first rotating shaft 61 side and a fixed part 63b provided on the second rotating shaft 64 side. The moving part 63a is pressed against the fixed part 63b side by an elastic member such as a spring (not shown), and the convex part 63c on the moving part 63a side is coupled to the concave part 63d on the fixed part 63b side of the coupling mechanism 63. The shafts 61 and 64 are integrally rotatable. Note that the projections 63c may be provided on the fixed portion 63b side, and the recesses 63d may be provided on the moving portion 63a side, with the concave / convex forming portions reversed.

By moving the moving part 63a away from the fixing part 63b of the connecting mechanism 63 by an external input from a driving source such as a push solenoid (not shown), the connection between the fixing part 63b and the moving part 63a is separated. The rotating shaft 61 and the second rotating shaft 64 can be rotated independently. At this time, the first pinion gear 62 and the second pinion gear 65 can rotate independently.

At this time, the first pinion gear 62 meshes with the first rack bar 53, and the second pinion gear 65 meshes with the second rack bar 54. Further, the first rack bar 53 and the second rack bar 54 are engaged with each other by a first synchronization gear 55. For this reason, with the rotation input to the first pinion gear 62, the first rack bar 53 moves in the lateral direction (one direction) along the parallel direction of the rack teeth, that is, the left-right direction of the vehicle. When the first rack bar 53 moves in the lateral direction, the first synchronization gear 55 rotates, and the second rack bar 54 moves in the opposite direction (the other direction) from the first rack bar 53 by the same distance. At this time, the second pinion gear 65 rotates as the second rack bar 54 moves.

In this way, by switching the coupled state and the separated state of the first pinion gear 62 and the second pinion gear 65 with the coupling mechanism 63, the pair of rack bars 53 and 54 are integrally moved in the same direction by the same distance, It is possible to easily change the state of moving separately in the opposite direction.

That is, when the connecting mechanism 63 is connected to the first rack bar 53 and the second rack bar 54 via the first pinion gear 62 and the second pinion gear 65, The left and right wheels w are moved in the same direction around the kingpin axis P (see FIG. 7) by integrally moving the first rack bar 53 and the second rack bar 54 in the same direction in the left and right direction with respect to the straight traveling direction of the vehicle. Can be steered. At this time, since the first rack bar 53 and the second rack bar 54 move together, the first synchronization gear 55 does not rotate.

Further, in a state where the coupling mechanism 63 separates the first pinion gear 62 and the second pinion gear 65, the first rack bar 53 and the second rack bar 54 are moved in opposite directions in the left and right direction with respect to the straight traveling direction of the vehicle. By moving, the left and right wheels can be steered in opposite directions around the kingpin axis P (see FIG. 7), that is, in directions opposite to each other.

Thus, the rack bar operating means 60 also functions as means for moving the first rack bar 53 and the second rack bar 54 together during normal operation.

Further, when the driving force of the mode switching actuator 32 is input to the rack bars 53 and 54 through the rotation of the first pinion gear 62 during the mode switching, the rotation of the steering 2 is not transmitted to the steering shaft 3. Alternatively, the transmission may be allowed.

Furthermore, the normal steering actuator 31 can also serve as the mode switching actuator 32. That is, at the time of mode switching, the first rotating shaft 61 may be rotated by the driving force of the normal steering actuator 31 via the steering shaft 3.

Further, the mode switching actuator 32 can also serve as the driving force of the in-wheel motor M disposed on the left and right of the steering 2. Furthermore, the normal steering actuator 31, the mode switching actuator 32, or the left and right in-wheel motors M can also assist each other.

As shown in FIGS. 12, 13A, and 13B, the steering devices 10 and 20 include rack bar movement amount detection means 70 that detects the movement amount of one of the pair of rack bars. In this embodiment, the rack bar movement amount detection means 70 detects the movement amount of the first rack bar 53 in the left-right direction. Installation of the rack bar movement amount detection means 70 is omitted from the second rack bar 54.

The first pinion gear 62 that meshes with the steering rack gear 53 b of the first rack bar 53 is meshed with a movement amount detection gear 71, and the movement amount detection gear 71 is rotated by the rotation of the movement amount detection gear 71. A pulsar gear 72 that rotates with the rotation is provided. Further, a magnetic sensor 73 is provided at a position facing the pulsar gear 72. The magnetic sensor 73 includes a detection element and a detection coil for converting a change in the magnetic field into an electric signal, and measures the amount of rotation of the pulsar gear 72. The magnetic sensor 73, the movement amount detection gear 71, and the pulsar gear 72 constitute a movement amount detection means 70 that detects the movement amount of the first rack bar 53 to the left and right.

When the first pinion gear 62 rotates as the first rack bar 53 moves in the left-right direction, the movement amount detection gear 71 rotates along with the rotation, and the rotation of the movement amount detection gear 71 further rotates. Accordingly, the pulsar gear 72 rotates. Then, an electric signal is generated from the magnetic sensor 73, and the rotational speed of the pulsar gear 72 and further the turning angle of the left and right wheels w are calculated from the electric signal by the steering devices 10 and 20 and the electronic control unit 40. It can be calculated from the means.

Further, as shown in FIG. 13B, an auxiliary gear 74 that meshes with the steering rack gear 54b of the second rack bar 54 is further provided, and the auxiliary gear 74 and the second pinion gear 65 are directly or via other gears. It is preferable to be configured to indirectly mesh with each other. When the auxiliary gear 74 is provided, the overlapping range of the rack teeth of the first rack bar 53 and the second rack bar 54 in the parallel direction becomes small, and the second pinion gear 65 and the turning rack gear 54b are not meshed. In this case, the auxiliary gear 74 can mesh with the steering rack gear 54b to move the second rack bar 54.

The operation angle of the steering wheel 2 by the driver or the target turning angle of the wheel w corresponding to the traveling mode is compared with the actual current turning angle of the wheel w calculated by the calculation means, and the target turning angle and the current turning angle are compared. Feedback control is performed so that the difference from the rudder angle is less than or equal to a predetermined value.

In the above embodiment, the pulsar gear 72 is used, but a magnetic encoder can also be used. Since the pulsar gear 72, the magnetic encoder, and the magnetic sensor 73 are not easily affected by dust, dust, etc., even when used in the vehicle 1, high detection accuracy can always be maintained. In an environment (configuration) in which measures such as dust or dust are taken, an optical rotation sensor can be employed.

Here, the steering devices 10 and 20 are fixed to the rack case 50 attached to the frame so that the synchronous gear box 66 for storing the synchronous gear device 57 is not moved to a predetermined position. A fixing mechanism 80 that prevents relative movement between the rack case 50 and the synchronous gear box 66 is provided. By providing this fixing mechanism 80, a difference occurs between the intended turning angle and the actual turning angle due to the influence of the road surface condition (inclination of the left and right tire contact surfaces, difference in friction state, etc.). Can be prevented.

The fixing mechanism 80 is used during special turning (when the first rack bar 53 and the second rack bar 54 are moved in opposite directions along the parallel direction of the rack teeth), during straight traveling, during normal turning, etc. The synchronous gear box 66 has a function of restricting movement of the rack teeth in the parallel direction.

As shown in FIGS. 16A and 16B, the fixing mechanism 80 of this embodiment is based on the straight-running gearbox position, which is the position of the synchronous gearbox 66 when the vehicle is straight running, in one direction from the straight-running gearbox position, for example, The first fixed portion 81 that restricts the movement of the synchronous gear box in the right direction of the vehicle body and the second fixed portion 86 that restricts the movement of the synchronous gear box 66 in the other direction, for example, the left direction of the vehicle body. is doing. The straight-running gearbox position is usually set at a position where the center of the vehicle body in the width direction and the center of the synchronization gearbox 66 in the length direction (in parallel direction of the rack teeth) coincide with each other. The first fixing portion 81 and the second fixing portion 86 of the fixing mechanism 80 are fixed to both ends of the rack case 50.

The first fixing portion 81 and the second fixing portion 86 of the fixing mechanism 80 are provided at both ends in the length direction of the synchronous gear box 66. As shown in FIGS. 15A to 15C, the first and second fixing portions 81 and 86 are moved in and out by the operations of the electromagnetic solenoids 82 and 87, respectively. It consists of lock pins 83 and 88.

The left and right lock pins 83 and 88 protrude toward the synchronous gear box 66 when the electromagnetic solenoids 82 and 87 are turned on, and restrict the predetermined movement of the synchronous gear box 66 in the left-right direction of the vehicle body. Hereinafter, this state is referred to as a regulated state. Further, the left and right lock pins 83 and 88 are retracted when the excitation operation of the electromagnetic solenoids 82 and 87 is turned off, and the movement of the synchronous gear box 66 in the left-right direction of the vehicle body is not restricted. This state is hereinafter referred to as an unregulated state. The lock pins 83 and 88 are held by a lock pin case 84 (see FIG. 8) fixed to the rack case 50.

Details of the fixing mechanism 80 are shown in FIGS. 15A to 15C. 15A is a side view of the fixing mechanism 80 viewed from the side of the lock pins 83 and 88, and FIGS. 15B and 15C show operations of the lock pins 83 and 88 in the II cross-sectional view of FIG. 15A. FIG. 15B shows a state in which the electromagnetic solenoids 82 and 87 are de-energized and the lock pins 83 and 88 are retracted (retracted) by the restoring force of the coil spring 85. FIG. 15C shows a state in which the lock pins 83 and 88 protrude (advance) due to the excitation operation of the electromagnetic solenoids 82 and 87. In this manner, the lock pins 83 and 88 are protruded and retracted depending on whether the electromagnetic solenoids 82 and 87 are excited.

Further, the fixing mechanism 80 includes a detection mechanism 89 (see FIG. 8) for detecting whether the first fixing portion 81 and the second fixing portion 86 are in a restricted state or an unregulated state, respectively. The detection mechanism 89 is a lock pin sensor that detects whether each of the lock pins 83 and 88 is in a protruding state or a retracted state. As this lock pin sensor, for example, a non-contact type sensor using light, magnetism, or the like may be used, and an engagement element that engages with the lock pins 83 and 88 is provided, and the lock pins 83 and 88 protrude and retract. It may be a contact type sensor that detects the movement of the engaging member accompanying the movement of the. In the embodiment, the position of the magnet attached to the lock pins 83 and 88 is detected by the magnetic sensor as the strength of the magnetic force, and the projection and retraction operation states of the lock pins 83 and 88 are detected. .

The positional relationship between the synchronous gear box 66 and the lock pins 83 and 88 is shown in FIGS. 16A and 16B. In FIG. 16A, the electromagnetic gear 82 of the first fixed portion 81 (see FIGS. 15A to 15C) and the second state with the synchronous gear box 66 shifted from the gear box position to the left in the vehicle body width direction as the initial state. Both electromagnetic solenoids 87 of the fixed part 86 are excited. This excitation is instructed by the electronic control unit 40 in accordance with various driving situations and steering operations performed by the driver.

At this time, the lock pin 83 of the first fixing portion 81 cannot protrude due to the side surface 66b of the synchronous gear box 66 being an obstacle. On the other hand, the lock pin 88 of the second fixing portion 86 protrudes because there is no obstacle. The detection mechanism 89 (see FIG. 8) detects the state of the left and right lock pins 83, 88, so that the synchronous gear box 66 is biased to the left without detecting the amount of movement of each rack bar 53, 54. It can be determined that it is in a state.

Therefore, with the left and right electromagnetic solenoids 82 and 87 excited, rotation is input through the steering input shaft 33 (see FIG. 8) or by the mode switching actuator 32 (see FIGS. 2A and 2B), and the synchronous gearbox. The rack bar operating means 60 is operated so that 66 moves to the right in the vehicle body width direction. Then, the synchronous gear box 66 moves to the position shown in FIG. 16B, and the end surface 66a in the length direction of the synchronous gear box 66 interferes with the lock pin 88 of the second fixing portion 86 in the protruding state and stops.

At this time, the side surface of the synchronous gear box 66 that has been an obstacle to the protrusion of the lock pin 83 of the first fixed portion 81 is disengaged from the position where the lock pin 83 is opposed. As a result, the lock pin 83 protrudes. By detecting the states of the left and right lock pins 83 and 88 by the detection mechanism 89 (see FIG. 8), it can be determined that the position of the synchronous gear box 66 is fixed at the gear box position when traveling straight.

In the initial state, when the synchronous gearbox 66 is shifted from the gearbox position to the right in the vehicle body width direction when traveling straight, the left and right of the above procedure are reversed. For this reason, if the position of the synchronous gearbox 66 is fixed at the straight-running gearbox position in the same procedure in which the left and right are reversed, it can be determined that the fixing is achieved. When the synchronous gear box 66 is in the straight gearbox position as an initial state, both the left and right lock pins 83 and 88 protrude as they are, and the synchronous gear box 66 is fixed at the straight gearbox position. Can be determined.

Here, as shown in FIGS. 13A and 13B, the movement amount detection means 70 detects the movement amount of the first rack bar 53 in each of the normal turning and special turning scenes. When the synchronous gear box 66 is in the straight gearbox position, the movement amount of the second rack bar 54 is the same as the movement amount of the first rack bar 53. However, when the position of the synchronous gear box 66 is unknown, the amount of movement of the second rack bar 54 is unknown. Therefore, as described above, the amount of movement of the second rack bar 54 is clarified by fixing the synchronous gear box 66 to the gear box position at the time of straight traveling and performing predetermined steering, and appropriately switching the traveling mode. It becomes possible. All these determinations and controls are performed by the electronic control unit 40.

As described above, by providing the fixing mechanism 80, when the synchronous gear box 66 is in a position shifted in one direction from the linear gearbox position, the first fixing portion 81 moves the synchronous gear box 66. When the non-regulated state is set to the non-regulated state, and the synchronous gear box 66 reaches the gear box position when the synchronous gear box 66 travels in the other direction from the state, the first fixing portion 81 66 is set to a restricted state that restricts movement in one direction from the gearbox position when traveling straight.
Further, when the synchronous gear box 66 is in a position shifted in the other direction from the straight gearbox position, the second fixing portion 86 is set to an unregulated state in which the movement of the synchronous gear box 66 is not restricted. When the synchronous gear box 66 reaches the gearbox position when traveling straight due to the movement of the synchronous gearbox 66 in one direction from the state, the second fixing portion 86 moves the synchronous gearbox 66 from the gearbox position when traveling straight to the other direction. It is set to a restricted state for restricting movement.

Further, whether or not the synchronous gear box 66 shifts left and right from the gear box position when the straight gear travels straight, depending on whether the first fixing portion 81 and the second fixing portion 86 are detected by the detection mechanism 89. Further, the shift direction can be determined, and the synchronization gear box 66 can be moved toward the gear box position when traveling straight, thereby eliminating the shift of the synchronization gear box 66 in the vehicle body width direction. As described above, the fixing mechanism 80, the detection mechanism 89, the rack bar operation means 60, and the like exhibit a function of eliminating the shift of the synchronous gear box 66 in the vehicle body width direction under the control of the electronic control unit 40. A deviation canceling means of the synchronous gear box 66 is configured.

Hereinafter, several traveling modes when the steering devices 10 and 20 having these respective configurations are mounted on the vehicle 1 will be described.

(Normal driving mode)
2A and 2B, the first rack bar 53 and the second rack bar 54 of the front wheel steering device 10 can be moved integrally, that is, the coupling mechanism 63 is coupled. The entire rack case 50 of the steering device 10 moves integrally in the left-right direction within the holding case attached to the frame of the vehicle 1.

When the steering device 10 is moved in the left-right direction with respect to the straight traveling direction by the driving force of the normal steering actuator 31 or the operation of the steering 2, the first rack bar 53 and the second rack bar 54 are integrally formed in the same direction. By moving the same distance, as shown in FIG. 3, the left and right wheels w of the front wheels are steered to a predetermined angle. FIG. 3 shows the case of turning to the right. In other words, by completely fixing the first rack bar 53 and the second rack bar 54 together, it is possible to travel equivalent to a normal vehicle. In the normal travel mode, the driver can operate the steering 2 through the front wheel steering device 10 to make a straight turn, right turn, left turn, and other necessary turning according to each scene.

(Turn mode)
The small turning mode is shown in FIG. In addition to the operation of the front-wheel steering device 10 shown in FIG. 3, the first rack bar 53 and the second rack bar 54 of the rear-wheel steering device 20 can be moved together, that is, the coupling mechanism 63 is coupled. As with the front wheels, the steering device 20 moves integrally in the left-right direction within a holding case attached to the frame of the vehicle 1.

When the rear wheel steering device 20 is moved in the left-right direction with respect to the straight traveling direction by the driving force of the normal steering actuator 31, the first rack bar 53 and the second rack bar 54 are also integrated in the same direction and at the same distance. As shown in FIG. 4, the left and right wheels w of the rear wheels are steered to a predetermined angle. At this time, the rear wheels and the front wheels are steered in opposite phases (in FIG. 4, the front wheels are steered to the right and the rear wheels are steered to the left) and have a smaller turning radius than in the normal travel mode. Small turning is possible. 4 shows a state in which the rear wheels and the front wheels are steered by the same angle in opposite phases, the steered angles may be different between the front and rear.

(Spot turn mode)
The spot turn mode is shown in FIG. By separating the coupling mechanism 63, the first rack bar 53 and the second rack bar 54 can be operated separately. At this time, the driving force is input from the mode switching actuator 32 to the first pinion gear 62, and the first rack bar 53 and the second rack bar 54 move the same distance in opposite directions. That is, if the first synchronization bar 55 is interposed between the first rack bar 53 and the second rack bar 54 and the first rack bar 53 moves in one direction in the left-right direction, the second rack bar 54 Move in the direction.

The first rack bar 53 and the second rack bar 54 are moved in opposite directions, and the coupling mechanism 63 is coupled and fixed at a position where the central axes of all the four front and rear wheels w are substantially directed to the vehicle center as shown in FIG. Let Since the central axes of all four wheels w are substantially directed to the vehicle center, the vehicle center does not move from the place (or almost does not move) by the driving force of the in-wheel motor M provided on each wheel w. ), So-called in-situ turning is possible.

In FIG. 5, each wheel w is equipped with an in-wheel motor M. However, if at least one wheel w is equipped with an in-wheel motor M, and that one in-wheel motor M is activated, in-situ turning is performed. Is possible.

(Lateral movement mode)
The lateral movement mode is shown in FIG. Similarly to the in-situ turning mode, the coupling mechanism 63 is separated, and the mode switching actuator 32 is arranged so that all the four front and rear wheels w are directed in a direction of 90 degrees with respect to the straight traveling direction (the left-right direction with respect to the straight traveling direction of the vehicle). By the rotation input to the first pinion gear 62, the first rack bar 53 and the second rack bar 54 in the steering devices 10 and 20 are moved in opposite directions. Then, the coupling mechanism 63 is coupled at the position where the wheel w is 90 degrees, and the pair of rack bars 53 and 54 are fixed.

At this time, as a fine adjustment function, the first rack bar 53 and the second rack bar 54 in the steering devices 10 and 20 are integrated with respect to the straight traveling direction by the driving force of the normal steering actuator 31 or the operation of the steering 2. It is possible to finely adjust the direction of the wheel w (tire angle) by moving the wheel w to the left and right.

FIG. 6 shows the positional relationship between the front and rear wheel steering devices 10 and 20 and the direction of the wheels w in the lateral movement mode. The first rack bar 53 and the second rack bar 54 further project outward as compared with the in-situ turning mode, and the connection portion of the tie rods 12 and 22 to the wheel w is the outermost side in the vehicle width direction. It is a driving mode located in the. Even in this lateral movement mode, the direction (tire angle) of the wheel w can be finely adjusted by the driving force of the normal steering actuator 31 or the operation of the steering 2.

(Other travel modes)
As another driving mode, for example, when the electronic control unit 40 recognizes that the vehicle 1 is traveling at a high speed, the actuator driver 30 can change the rear wheel mode switching actuator based on the output of the electronic control unit 40. 32, the left and right wheels w (RL, RR) of the rear wheels are set to a state (toe-in state) where the front side is slightly closed from the parallel state. Thereby, the stable high-speed driving | running is attained.

This toe adjustment may be automatically performed based on the determination of the traveling state such as the vehicle speed and the load applied to the axle by the electronic control unit 40, or input to the mode switching means 42 provided in the cab. It may be performed based on this. The driving mode can be switched by operating the mode switching means 42 by the driver. The mode switching means 42 may be, for example, a switch, lever, joystick, etc. that can be operated by the driver.

(Mode switching, turning amount control)
It should be noted that this mode switching means 42 is used as appropriate when switching between the above-described travel modes. By operating the mode switching means 42 in the passenger compartment, it is possible to select the normal traveling mode, the spot turn mode, the lateral movement mode, the small turn mode, and the like. If switching can be performed by a switch operation or the like, safer operation is possible.

In normal steering, the front wheel steering device 10 requires the electronic control unit 40 in the left and right directions of the first rack bar 53 and the second rack bar 54 based on information from the sensor 41 accompanying the rotation operation of the steering wheel 2. Calculate and output the amount of motion. Based on the output, the front wheel normal steering actuator 31 is commanded to move the rack case 50 containing the first rack bar 53 and the second rack bar 54 integrally in the left-right direction, and to move the left and right wheels w in the required direction. Steer only to the required angle.

In special steering, in the front and rear wheel steering devices 10 and 20, information from the sensor 41 that detects the steering angle or steering torque of the steering wheel 2 in the driver's seat, input from the mode switching means 42, rack bar movement Based on the information from the amount detection means 70, the electronic control unit 40 outputs the required amount of operation of the first rack bar 53 and the second rack bar 54 in the left-right direction. Alternatively, the necessary movement amounts of the first rack bar 53 and the second rack bar 54 are output based on the determination of the traveling state by the electronic control unit 40 itself. Based on the output, the actuator driver 30 can steer the front and rear wheels in a predetermined direction through the normal steering actuator 31 and the mode switching actuator 32.

The various travel modes described above are examples, and various other controls using these mechanisms are possible. In addition, although a pair of fixing parts arranged at both ends of the synchronous gear box is shown as a fixing mechanism, the present invention is not limited to this, and a concave part is provided in the synchronous gear box so that one lock pin can be advanced and retracted in the rack case. It is possible to add various modifications and variations within the same range as the invention, such as a fixing method, or within an equivalent range.

DESCRIPTION OF SYMBOLS 1 Vehicle 2 Steering 3 Steering shafts 12, 22 Tie rod 50 Rack case 53 First rack bar 54 Second rack bar 55 Synchronous gear 60 Rack bar operating means 62 First pinion gear 63 Connection mechanism 66 Synchronous gear box 70 Rack bar movement amount detection Means 80 Fixing mechanism 89 Detection mechanism w Wheel

Claims (6)

Tie rods (12, 22) connected to the left and right wheels (w) of the front wheels or rear wheels and steering the left and right wheels (w), and pairs connected to the tie rods (12, 22) of the left and right wheels (w), respectively. The rack bar (53, 54) and the pair of rack bars (53, 54) are engaged with each other, and the movement of the rack teeth of one rack bar in one direction relative to the parallel direction of the rack teeth is changed in the other direction of the other rack bar. Synchronous gear device (57) for converting into motion, and rack bar operating means capable of moving said pair of rack bars (53, 54) in opposite directions along the parallel direction of the rack teeth of each rack bar (60), a synchronous gear box (66) that holds the synchronous gear device (57) and is movable in the parallel direction, and holds the pair of rack bars (53, 54) and Frame side Includes rack and casing (50) which is fixed, and the fixing mechanism is held in the rack casing (50) (80), a
When the pair of rack bars (53, 54) are moved in the opposite direction along the parallel direction, the fixing mechanism (80) regulates the movement of the synchronous gear box (66) in the parallel direction. A steering apparatus characterized by the above. The fixing mechanism (80) is a pair of fixing mechanisms arranged at both ends of the synchronous gear box (66), and is based on the straight gearbox position that is the position of the synchronous gearbox (66) when the vehicle goes straight, The fixing mechanism (80) includes a first fixing part (81) for restricting the movement of the synchronous gear box (66) in one direction from the position of the straight gearbox, and the synchronous gear box (66 in the other direction). The steering device according to claim 1, wherein the steering device is paired with a second fixing portion (86) that restricts the movement of the second fixing portion. When the synchronous gearbox (66) is in a position shifted in one direction from the linear gearbox position, the first fixing portion (81) does not restrict the movement of the synchronous gearbox (66). When the synchronous gearbox (66) reaches the gearbox position when traveling straight from the state by the movement of the synchronous gearbox (66) in the other direction, the first fixed portion (81) The synchronous gearbox (66) is set to a restricted state for restricting movement in one direction from the gearbox position when traveling straight,
When the synchronous gearbox (66) is in a position shifted in the other direction from the linear gearbox position, the second fixing portion (86) does not restrict the movement of the synchronous gearbox (66). When the synchronous gearbox (66) reaches the gearbox position during straight travel by moving the synchronous gearbox (66) in one direction from the state, the second fixing portion (86) The steering apparatus according to claim 2, wherein the synchronous gearbox (66) is set in a restricted state in which movement of the synchronous gearbox (66) is restricted from the gearbox position in the other direction. The steering device according to claim 3, wherein the first fixing portion (81) and the second fixing portion (86) are provided with detection mechanisms (89) for detecting whether the restricted state and the unregulated state, respectively. According to the regulation state and the non-regulation state in the first fixing portion (81) and the second fixing portion (86) detected by the detection mechanism (89), the linear movement of the synchronous gear box (66) is performed. 5. A deviation canceling means for judging whether or not there is a lateral shift from the hour gearbox position and a direction of the deviation, and moving the synchronous gearbox (66) toward the linear gearbox position. A steering device according to claim 1. The movement of the synchronous gear box (66) by the fixing mechanism (80) is restricted when the pair of rack bars (53, 54) are moved in opposite directions along the parallel direction of the rack teeth. The steering device according to any one of claims 1 to 5.

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