JP2016055804A - Steering device and method for changing driving modes of vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve a steering device with a simple structure having a function of changing driving modes from a normal driving mode to a special driving mode.SOLUTION: A steering device 1 includes: a knuckle 3 provided at a chassis through a suspension unit 2; a first king pin axis 4 for rotating the knuckle 3 with respect to the suspension unit 2, in a steering direction; a second king pin axis 5 for rotating a wheel W with respect to the knuckle 3, in a direction corresponding to a driving mode of a vehicle C; first drive means 7 for steering the wheel W around the first king pin axis 4; and second drive means (an in-wheel motor) M for steering the wheel W around the second king pin axis 5. The first king pin axis 4 is engaged in the normal steering, while the second king pin axis 5 is engaged in the changeover of driving modes.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a steering device employed in a vehicle that can switch a traveling mode between a normal traveling mode and a special traveling mode such as in-situ rotation, and a method for switching a traveling mode of a vehicle that employs the steering device. .

  Ackerman-Jantou type is used to steer the wheels using a steering link mechanism that connects the left and right wheels (hereinafter collectively referred to as "wheels" including tires, wheels, hubs, in-wheel motors, etc.) There is a steering device called. This steering device has a tie rod and a knuckle arm, and acts so that the left and right wheels have the same center of rotation when the vehicle rotates.

  As this steering apparatus, there exists a thing of the structure shown in patent document 1, for example. This steering device is provided with a steering link mechanism for left and right wheels using tie rods and knuckle arms 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 the angle formed between each wheel and the knuckle arm. By providing an actuator that changes this, all the normal traveling, parallel movement, and small traveling are smoothly performed, and excellent responsiveness is ensured.

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

  Patent Document 3 discloses a technique 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. Further, Patent Document 4 discloses a technique of a steering device in which toe adjustment of 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.

  According to a general Ackermann-Jantou type steering link mechanism, during normal driving, lines extending vertically from the rotation line of each wheel (the center line in the width direction of the wheel) gather in the center of rotation 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.

  Also, in this type of vehicle, the front wheels, which are the main steered wheels, are usually steered in a predetermined traveling direction of the vehicle, and the rear wheels, which are the follower steered wheels, are designed to be parallel to the longitudinal direction of the vehicle. Has been. For this reason, when the front wheel of this vehicle is steered and rotated, the rotation center of the front wheel and the rear wheel is not at the same position. For this reason, at low vehicle speeds, the vehicle rotates in a posture in which the rear wheels enter the inside of the rotation circle due to the inner wheel difference, and at high vehicle speeds, the vehicles rotate in a posture in which the front wheels enter the inside of the rotation circle by centrifugal force. That is, there is a problem that even if the front wheels are steered in the rotational direction that is the traveling direction of the vehicle, it is not possible to steer the vehicle so that the posture of the vehicle coincides with the rotational direction. Therefore, there is a vehicle having a four-wheel steering device that improves traveling performance by turning not only front wheels but also rear wheels.

  As a vehicle having a four-wheel steering device (a so-called 4WS vehicle), for example, the technique described in Patent Document 1 allows the vehicle to move in the lateral direction, turn around, and the like. However, in order to change the length of the tie rod, the distance between the left and right tie rods, or the angle between the wheel and the knuckle arm, many actuators are provided, and complicated control of each actuator is required. Further, the technique described in Patent Document 2 has a complicated structure due to its mechanism, and 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 between the gears, and it is difficult to smoothly steer the wheels.

  Moreover, although the technique of patent document 3 is an example of the conventional four-wheel steering apparatus and enables rear-wheel steering, lateral movement is difficult only with this mechanism. Furthermore, the technique of Patent Document 4 has a problem that it can not adjust to a lateral movement or a small turn of the vehicle while toe adjustment is possible.

  In order to solve the various problems of the steering device described in Patent Documents 1 to 4, the inventor of the present application has two rack bars that can be moved independently on the left and right as shown in Patent Document 5, and the rack bar The steering device was invented by connecting each of the left and right wheels via a tie rod and allowing the rack bar to move in the opposite direction with respect to the synchronous gear box by a synchronous gear held in the synchronous gear box. The two rack bars are each provided with a pinion gear that meshes with the rack bar, and a coupling mechanism is provided between the two pinion gears so that the rotation shafts of both the pinion gears can be coupled or separated. When this coupling mechanism is coupled, both rack bars can be moved together in the same direction by the same distance, that is, the left and right wheels can be steered in the same direction. On the other hand, when this coupling mechanism is separated, both rack bars can be moved in the opposite direction by the same distance, that is, the left and right wheels can be steered in the opposite direction.

  Here, turning the left and right wheels in the same direction corresponds to normal turning in a general vehicle. Further, turning the left and right wheels in the reverse direction corresponds to switching the travel mode from the normal travel mode to a special travel mode such as spot rotation or lateral movement. Both the normal turning and the switching of the traveling mode are transmitted to the wheel side through a tie rod as a rotation around one kingpin axis of a knuckle provided on each wheel. If this steering device is mounted on a vehicle, a special travel mode such as in-situ rotation and lateral movement can be performed, and a change from the normal travel mode to the special travel mode can be performed smoothly.

Japanese Patent Laid-Open No. 04-262971 Japanese Patent No. 4635754 Utility Model Registration No. 2600374 Japanese Patent Laid-Open No. 2003-127876 Japanese Patent Application No. 2013-158876 (unpublished)

  Since the steering device according to Patent Literature 5 plays both the role of normal steering and switching of the travel mode, compared to a general rack-and-pinion type steering device, the steering device such as a rack and gears is used. Requires many parts. For this reason, as compared with a general steering device, there are many problems such as difficulty in cost reduction, and the device configuration becomes large and the mounting method on the vehicle is likely to be restricted.

  Accordingly, an object of the present invention is to realize a steering device having a function of switching from the normal travel mode to the special travel mode with a simple configuration.

  In order to solve this problem, in the present invention, a knuckle provided in a chassis via a suspension device, a first kingpin shaft for rotating the knuckle in a steering direction with respect to the suspension device, A second kingpin shaft for rotating the wheel in a direction corresponding to a traveling mode of the vehicle with respect to a knuckle; a first driving means for turning the wheel around the first kingpin shaft; And a second driving means for turning the wheel about the kingpin axis.

  In this way, by dividing the kingpin axis into the first kingpin axis and the second kingpin axis, the first kingpin axis is involved in normal steering while the second kingpin axis is in the travel mode. It can also be involved in switching. In this case, the tie rod of the steering device is connected to the first kingpin shaft side, and the steering device only has to perform normal steering. Therefore, a general rack and pinion is used as the first drive means of the steering device. A formula can be adopted. For this reason, the structure can be simplified and the mounting property to a vehicle can be ensured.

  On the second kingpin shaft side, a second driving means that is a traveling mode switching mechanism is provided. Specifically, as the second driving means, an in-wheel motor is mounted inside the wheel, the in-wheel motor is driven to rotate the wheel, and the wheel is rotated around the second kingpin axis by this rotational force. It is convenient and preferable to make it move. By operating this switching mechanism, the vehicle driving mode can be switched smoothly.

  The first kingpin shaft and the second kingpin shaft are either of a configuration that actually includes a shaft body or a configuration that does not actually have a shaft body and rotates around a predetermined rotation axis. Also good.

  In the said structure, it is preferable to set it as the structure further equipped with the lock mechanism which fixes rotation of the said wheel around said 2nd kingpin axis | shaft. By providing a lock mechanism, it is possible to prevent the wheels from rotating around the second kingpin axis and changing the angle inadvertently during normal steering, and operational stability And driving stability can be ensured.

  In each of the above configurations, the knuckle rotation about the first kingpin axis is performed in accordance with the steering operation of the wheel, while the rotation of the wheel about the second kingpin axis is It is preferable to adopt a configuration that is made in accordance with an operation for changing the travel mode of the vehicle. Thus, by setting the rotation axis of the knuckle and the rotation axis of the wheel separately, the first kingpin axis and the second kingpin axis are set to an inclination angle suitable for each rotation axis. The wheel can be steered and the driving mode can be switched more smoothly.

  The rotation of the knuckle around the first kingpin axis is made in accordance with the steering operation of the wheel, while the rotation of the wheel around the second kingpin axis is the driving mode of the vehicle. In the configuration made in accordance with the change operation, the scrub radius of the second kingpin shaft is larger than the scrub radius of the first kingpin shaft. It is preferable that the kingpin shaft is arranged.

  The scrub radius is the distance between the point at which the kingpin axis intersects the ground and the center of the tire's ground contact surface. The scrub radius, along with the position and inclination of the kingpin axis, affects the vehicle's running characteristics and turning characteristics. It has a big impact. Specifically, when the scrub radius is increased, the switching characteristics of the driving mode by the switching mechanism are improved, but the driving characteristics of the vehicle may be deteriorated. In this way, the kingpin axis is configured separately with the first kingpin axis and the second kingpin axis, the first kingpin axis is used for wheel steering operation, and the second kingpin axis is used for switching the driving mode. By functioning, it is possible to achieve both of ensuring the traveling characteristics and ensuring the switching characteristics of the traveling mode by the switching mechanism.

  In each of the above configurations, the second drive means for turning the wheel around the second kingpin axis is an in-wheel motor, or a power source such as a hydraulic cylinder, a pneumatic cylinder, an electric cylinder, a motor, and a speed reducer. It is preferable to have a configuration consisting of

  As described above, instead of configuring the kingpin shaft with the first kingpin shaft and the second kingpin shaft, the wheel corresponds to the traveling mode of the vehicle with respect to the suspension device according to the switching operation of the traveling mode of the vehicle. It can also be set as the structure provided with the kingpin axis | shaft rotated in the direction to do. For example, in the case of a vehicle having a steering device on two front wheels (a so-called 2WS vehicle), it is not necessary to steer the two rear wheels, so that the kingpin shaft related to the travel mode switching mechanism (in each configuration described above, the second If the wheel is rotated by a switching mechanism around (around the kingpin axis), the driving mode of the two wheels that are not involved in normal steering can be switched.

  In the configuration including the kingpin shaft, it is preferable to further include a lock mechanism that fixes the rotation of the wheel around the kingpin shaft. In this way, by providing the lock mechanism, it is possible to prevent the wheel stability from being changed carelessly after the travel mode is switched and the travel stability from being impaired.

  Further, a knuckle provided on the chassis via a suspension device on at least one of the front and rear wheels, a first kingpin shaft for rotating the knuckle in a steering direction with respect to the suspension device, and the knuckle And a second kingpin shaft that rotates the wheel in a direction corresponding to the vehicle driving mode, and when the vehicle driving mode is changed by the steering device, either the front or rear side The vehicle travel mode switching method is configured to prevent the vehicle from moving during the travel mode switching while rotating the other wheel around the second kingpin axis while preventing the other wheel from rotating. did.

  In driving mode switching, since it is necessary to rotate a wheel for switching the driving mode, the vehicle may inadvertently move back and forth with the rotation. Therefore, by preventing the other wheel that is not related to the switching of the traveling mode from rotating, it is possible to prevent the vehicle from inadvertently moving during the switching of the traveling mode. As means for stopping the rotation of the wheel on the other side, a braking force is applied to the wheel, or a switching mechanism (such as an in-wheel motor) provided on the wheel is applied in a direction opposite to the direction in which the wheel is intended to rotate. Can be.

  Furthermore, the knuckle provided in the chassis via the suspension device on the front and rear wheels, the first kingpin shaft for rotating the knuckle in the steering direction with respect to the suspension device, and the wheel against the knuckle And a second kingpin shaft for rotating the vehicle in a direction corresponding to the travel mode of the vehicle. When changing the travel mode of the vehicle by the steering device, both the front and rear wheels are The vehicle driving mode switching method is configured so that the vehicle does not move during the switching of the driving mode.

  As described above, when the front and rear wheels are moved in cooperation instead of stopping the rotation of either front or rear wheels, the moving directions of the vehicles accompanying the rotation of the front and rear wheels are opposite to each other on the same axis. Then, it is possible to prevent the vehicle from inadvertently moving during the switching of the driving mode.

  In the present invention, a knuckle provided in a chassis via a suspension device, a first kingpin shaft for rotating the knuckle in a steering direction with respect to the suspension device, and the wheel with respect to the knuckle A second kingpin shaft that rotates in a direction corresponding to the travel mode, first driving means that steers the wheel about the first kingpin axis, and the wheel about the second kingpin axis. And a second drive means for turning.

  In this way, by configuring the kingpin shaft with the first kingpin shaft and the second kingpin shaft, the first kingpin shaft is involved in normal steering while the second kingpin shaft is switched to the driving mode. Can also be involved. In this case, the tie rod of the steering device is connected to the first kingpin shaft side, and the steering device only has to perform normal steering. Therefore, a general rack and pinion is used as the first drive means of the steering device. A formula can be adopted. For this reason, the structure can be simplified and the mounting property to a vehicle can be ensured.

  Furthermore, the second kingpin shaft side is provided with a second drive means that is a travel mode switching mechanism, which drives the switching mechanism to rotate the wheel, and this rotational force causes the wheel to move around the second kingpin shaft. By making it rotate, the driving mode of the vehicle can be switched easily and smoothly.

1 shows an embodiment of a steering device according to the present invention, where (a) is a front view and (b) is a side view. 1 is a perspective view of the steering device shown in FIG. FIG. 1 is an image diagram of a vehicle equipped with the steering device shown in FIG. FIG. 3 is a plan view showing a straight traveling state of the vehicle shown in FIG. The top view which shows the right turn state of the vehicle shown in FIG. The top view which shows the state which was set as the spot rotation mode in the vehicle shown in FIG. FIG. 3 is a plan view showing a state where the vehicle shown in FIG. FIG. 3 is a plan view showing a state in which the vehicle shown in FIG.

  After describing the configuration of the steering device 1 according to the present invention, a method for switching the travel mode of the vehicle C equipped with the steering device 1 will be described.

(1) Configuration of Steering Device FIGS. 1 and 2 show an embodiment of a steering device 1 according to the present invention. 1A is a front view, FIG. 1B is a side view, and FIG. 2 is a perspective view.

  The steering device 1 includes a knuckle 3 provided on a chassis (not shown) of a vehicle C (see, for example, FIG. 3) via a suspension device 2 (upper arm 2a, lower arm 2b), and a knuckle for the suspension device 2. Basically, a first kingpin shaft 4 that rotates 3 in the steering direction and a second kingpin shaft 5 that rotates the wheel W in directions corresponding to various travel modes of the vehicle C with respect to the knuckle 3. The configuration. In addition, the direction of the wheel W corresponding to the various driving modes of the vehicle C will be described in detail in item (2).

  The knuckle 3 is connected to the tie rod 6 by a first kingpin shaft 4 having rotating shafts 4a and 4b at the upper and lower ends of the knuckle 3. The tie rod 6 is connected to a steering device 7 (7a, 7b) (first driving means) (see FIG. 4 and the like) that steers the wheel W. By driving the steering device 7 and moving the tie rod 6, the knuckle 3 can be rotated around the first kingpin shaft 4 to steer the wheels W. Although this steering device 7 is not shown in the drawing, there are various types such as those that are steered by a steering operation by a driver or automatic driving, such as a rack-and-pinion method or a steer-by-wire method that operates by the action of a sensor and an actuator It can be adopted from those of the system. The wheel W incorporates an in-wheel motor M (second driving means), and driving the in-wheel motor M can switch the traveling mode and perform normal traveling of the vehicle C.

  The second kingpin shaft 5 has rotation shafts 5a and 5b closer to the center of the knuckle 3 than the first kingpin shaft 4, and the wheel W can be rotated on the second kingpin shaft 5. Is provided. The distance between the point where each kingpin shaft 4, 5 intersects the ground and the center of the ground contact surface of the tire (hereinafter referred to as the scrub radius) is the first scrub radius r2 of the second kingpin shaft 5 is the first. The kingpin shafts 4 and 5 are arranged so as to be larger than the scrub radius r1 of the kingpin shaft 4.

  In general, the position and inclination of the kingpin shaft and the size of the scrub radius greatly affect the running characteristics and turning characteristics of the vehicle. Specifically, when the scrub radius is increased, the traveling characteristics of the vehicle C may be deteriorated while the switching characteristics of the traveling mode by the switching mechanism are improved. In this way, the kingpin shaft is composed of the first kingpin shaft 4 and the second kingpin shaft 5 separately, the first kingpin shaft 4 is used for the steering operation of the wheel W, and the second kingpin shaft 5 is used as the traveling mode. In addition, the scrub radius r2 of the second kingpin shaft 5 is configured to be larger than the scrub radius r1 of the first kingpin shaft 4, thereby ensuring running characteristics, It is possible to achieve both of the switching characteristics of the traveling mode by the switching mechanism (in-wheel motor M).

  The knuckle 3 is provided with a lock mechanism 8 that fixes the rotation of the wheel W around the second kingpin shaft 5. The lock mechanism 8 has an insertion hole and a lock body 9 fixed to the knuckle 3, and a plurality of engagement recesses 10a, 10b, and 10c inserted into the insertion hole. It has a provided lock bar 11 and a solenoid operating part 12 for operating the lock part main body 9. Engagement protrusions (not shown) that can be engaged with the engagement recesses 10a, 10b, and 10c are provided in the lock body 9.

  By inserting the lock bar 11 into the insertion hole and operating the solenoid operating portion 12 in a state where any one of the engagement recesses 10a, 10b, and 10c is located in the lock portion main body 9, the engagement recess 12 Engagement or release (locking or unlocking) of the engaging protrusions 10a, 10b, and 10c can be performed freely. Here, the engagement recess 10a corresponds to the in-situ rotation mode, the engagement recess 10b corresponds to the small turn mode, and the engagement recess 10c corresponds to the lateral movement mode. The steering device 1 shown in FIG. 1 shows a state of a normal traveling mode, and although not shown in the drawing, an engagement recess corresponding to the normal traveling mode is provided in the lock body 9. Is located, and the engaging recess and the engaging protrusion are engaged.

  When the solenoid operating portion 12 is operated to bring the lock portion main body 9 into the unlocked state (the state where the engagement concave portion and the engagement protrusion are disengaged), and the in-wheel motor M is driven, the driving force is the second. The wheel W is steered by acting as a rotational force around the kingpin shaft 5. Then, the driving of the in-wheel motor M is stopped at the timing when any one of the engaging recesses 10a, 10b, and 10c is located in the lock portion main body 9. After this stop, the solenoid operating part 12 is operated again, and any one of the engaging recesses 10a, 10b, and 10c is engaged with the engaging protrusion in the lock part main body 9. Thereby, the switching to the travel mode corresponding to the positions of the respective engagement recesses 10a, 10b, and 10c is completed. The number of the engagement recesses 10a, 10b, and 10c is appropriately changed according to the number of travel modes employed in the vehicle C.

  In this embodiment, the lock mechanism 8 is composed of the lock unit main body 9, the lock bar 11, and the solenoid operating unit 12. However, for example, other fixings such as a rotating disk and a fixing pin for fixing the rotation of the rotating disk are possible. A structure can also be adopted. Moreover, in order to improve the certainty of a lock | rock, two or more fixing structures can also be used together. Further, the driving force of the in-wheel motor M is used for switching the traveling mode, but the in-wheel motor is used for switching the traveling mode by using a power source such as a hydraulic cylinder, a pneumatic cylinder, an electric cylinder, a motor and a speed reducer. The driving force of M can be used only for traveling of the vehicle C, or the in-wheel motor M can be omitted.

(2) Method for Switching Vehicle Driving Mode FIG. 3 shows an image diagram of a vehicle C in which the steering device 1 shown in FIG. The vehicle C is a two-seater (side-by-side two-seater) ultra-compact mobility. Note that the steering device 1 according to the present invention is not limited to this ultra-compact mobility, and can also be applied to a normal vehicle C. Each wheel W is provided with an in-wheel motor M, and a so-called 4WS configuration in which a steering device 7 (7a, 7b) is provided on each of the front wheels and the rear wheels is adopted. A rack-and-pinion type steering device 7 (7a, 7b) that steers by steer-by-wire based on the steering operation of the driver for the front wheels and the steering operation for the front wheels is adopted for the rear wheels.

  The travel mode of the vehicle C (see, for example, FIG. 3) will be described with reference to the vehicle plan views shown in FIGS. A white triangle described in each figure indicates the forward direction of the vehicle C during normal travel, and the white arrow indicates the travel direction of the vehicle C in each travel mode (or steered state). In these drawings, the details of the control system and the drive system between the front and rear steering devices 7a and 7b are omitted in order to pay attention to the steering direction of the wheel W in each traveling mode. .

(A) Normal driving mode (FIGS. 4 and 5)
In the normal travel mode, the lock mechanism 8 (see FIG. 1 and the like) is placed at a position corresponding to the normal travel mode of the lock bar 11 while the steering device 7 (7a, 7b) of the vehicle C is in a neutral (straight forward) state. Locked. By setting the lock mechanism 8 to the locked state, the wheel W and the knuckle 3 cannot be rotated relative to each other. Further, when the steering is operated to rotate the knuckle 3 around the first kingpin shaft 4, the wheel W can be steered to the left and right (FIG. 5 is a state steered to the right). When the in-wheel motor M provided on the wheel W is driven in a state where the front wheel is steered to the right as shown in FIG. 5, the vehicle C can be turned to the right as shown by a white arrow in the figure. . Although FIG. 5 shows a state in which only the front wheels are steered by the steering operation, the rear wheels may be steered in conjunction with the steering of the front wheels.

(B) In-situ rotation mode (Fig. 6)
When switching from the normal travel mode to the spot rotation mode, first, the lock mechanism 8 (see FIG. 1 and the like) of each steering device 1 is set to the unlocked state. Next, when the in-wheel motor M provided on the wheel W is driven in this state, the knuckle 3 that rotates around the first kingpin shaft 4 is maintained in its state by the tie rod 6, and instead the second knuckle 3. The wheel W is rotated around the kingpin shaft 5 and steered in the direction in which the rotation center axes of the four front and rear wheels intersect at the rotation center P1 of the vehicle C as shown in FIG. In this steered state, the lock mechanism 8 is brought into the locked state at the position (position 10a) corresponding to the in-situ rotation mode of the lock bar 11 (see FIG. 1 and the like). By setting the lock mechanism 8 in the locked state, the wheel W cannot be relatively rotated around the second kingpin shaft 5 of the knuckle 3. When at least one of the in-wheel motors M provided on each wheel W is driven in this state, the vehicle C rotates about the rotation center P1 and the in-situ rotation operation is realized. Note that the steering can also be operated in this in-situ rotation mode, and the steering center can be moved so as to shift the position of the rotation center P1 of the vehicle C.

(C) Lateral movement mode (FIG. 7)
When switching from the normal travel mode to the lateral movement mode, first, the lock mechanism 8 (see FIG. 1 and the like) of each steering device 1 is set to the unlocked state. Next, when the in-wheel motor M provided on the wheel W is driven in this state, the knuckle 3 that rotates around the first kingpin shaft 4 is maintained in its state by the tie rod 6, and instead of the knuckle 3. The wheel W rotates around the second kingpin shaft 5 and is steered so that the rolling direction of the four front and rear wheels is perpendicular to the normal straight traveling direction of the vehicle C as shown in FIG. In this steered state, the lock mechanism 8 is brought into a locked state at a position (position 10c) corresponding to the lateral movement mode of the lock bar 11 (see FIG. 1 and the like). By setting the lock mechanism 8 in the locked state, the wheel W cannot be relatively rotated around the second kingpin shaft 5 of the knuckle 3. When at least one of the in-wheel motors M provided on each wheel W is driven in this state, the vehicle C is realized in a lateral operation in which the vehicle C moves in a lateral direction with respect to the normal traveling direction. In this lateral movement mode, the steering can be operated, and the steering direction of the vehicle C can be adjusted to a direction slightly deviated from right to left by the steering operation.

(D) Small turn mode (Fig. 8)
When switching from the normal travel mode to the small turn mode, first, the lock mechanism 8 (see FIG. 1 and the like) of each steering device 1 is set to the unlocked state. Next, when an in-wheel motor M provided on the two wheels W of the front wheels is driven in this state, the knuckle 3 that rotates around the first kingpin shaft 4 maintains its state by the tie rod 6, The wheel W rotates around the second kingpin shaft 5 of the knuckle 3, and as shown in FIG. 8, the front wheel intersects at the rotation center P2 connecting the two rear wheels while keeping the rear wheel as it is. Steer in the direction. In this steered state, the lock mechanism 8 is brought into a locked state at a position (position 10b) corresponding to the small turning mode of the lock bar 11 (see FIG. 1 and the like). By setting the lock mechanism 8 in the locked state, the wheel W cannot be relatively rotated around the second kingpin shaft 5 of the knuckle 3. In this state, when at least one of the in-wheel motors M provided on the steered wheels W (the front wheels in FIG. 8) is driven, the vehicle C rotates about the rotation center P2 and a small turning operation is realized. . Thus, instead of turning the front wheels with the steering device 1 to change the travel mode, the rear wheels are steered with the steering device 1 to change the travel mode, while the front wheels are kept as they are. Even in this case, the small turning operation can be realized. Note that the steering can be operated even in the small turn mode, and the steering center can be moved so as to shift the position of the rotation center P2 of the vehicle C.

  As described in the above (b) to (d), when the traveling mode of the vehicle C is changed from the normal traveling mode to the special traveling mode such as the spot rotation mode by the steering device 1, either one of the front and rear The wheel W on the side is rotated around the second kingpin shaft 5 while the wheel W on the other side is prevented from rotating, and the traveling mode of the wheel W on the one side is switched. It is preferable that the traveling mode of the wheel W on the other side is switched so that the vehicle C does not rotate so that the vehicle C does not move during the switching of the traveling mode. Further, the three wheels W out of the four wheels are prevented from rotating, and the remaining one wheel is rotated around the second kingpin shaft 5 to switch the driving mode. It is also possible to prevent the vehicle C from moving during the switching of the traveling modes by sequentially rotating around the second kingpin shaft 5 and switching the traveling modes of all the wheels W.

  In the switching of the respective traveling modes, it is necessary to rotate the wheel W for switching the traveling mode, so that the vehicle C may move carelessly with the rotation. Thus, by preventing the other wheel W, which is not related to the switching of the traveling mode, from rotating, it is possible to prevent the vehicle C from inadvertently moving during the switching of the traveling mode. As a means for stopping the rotation of the wheel W on the other side, a brake is applied to the wheel W, or a switching mechanism (such as an in-wheel motor M) provided on the wheel W is opposite to the direction in which the wheel W is about to rotate. Can be given a driving force.

  As described above, instead of stopping the rotation of one of the front and rear wheels W, both the front and rear wheels W are rotated around the second kingpin shaft 5 so that the vehicle C does not move during the switching of the travel mode. May be. Even when the front and rear wheels W are moved jointly, if the moving directions of the vehicle C accompanying the rotation of the front and rear wheels W are mutually opposite on the same axis, carelessly during the switching of the driving mode This is because the vehicle C can be prevented from moving.

  In the above-described embodiment, the configuration including the first kingpin shaft 4 and the second kingpin shaft 5 is adopted in both the front and rear steering devices 1. The apparatus 2 may be configured to include only one kingpin shaft that rotates the wheel W in a direction corresponding to the traveling mode of the vehicle C. For example, in the case of a 2WS vehicle, the two rear wheels do not need to be steered. Therefore, the knuckle 3 is eliminated and the first kingpin shaft 4 is not provided, and the kingpin shaft related to the travel mode switching mechanism (each of the above-described configurations) In this case, if the wheel W is rotated by a switching mechanism around the second kingpin shaft 5), it is possible to switch between the two-wheel driving modes that are not involved in normal steering. .

  The steering device 1 according to the embodiment and the driving mode switching method of the vehicle C are merely examples, and the steering device 1 having a switching function from the normal driving mode to the special driving mode is realized with a simple configuration. As long as the problems of the present invention can be solved, it is allowed to change a part of the configuration of the steering device 1 or to additionally add other steps to the steps of the traveling mode switching method.

1 Steering device 2 Suspension device 3 Knuckle 4 First kingpin shaft 5 Second kingpin shaft 6 Tie rod 7 Steering device (first drive means)
8 Locking mechanism 9 Locking part body 10a, 10b, 10c Engaging recess 11 Lock bar 12 Solenoid action part r1 Scrub radius r2 (of the first kingpin axis) Scrub radius C of vehicle M In-wheel motor (Second drive means)
W wheel

Claims (7)

A knuckle (3) provided on the chassis via a suspension (2);
A first kingpin shaft (4) for rotating the knuckle (3) in a steering direction with respect to the suspension device (2);
A second kingpin shaft (5) for rotating the wheel (W) in a direction corresponding to the traveling mode of the vehicle (C) with respect to the knuckle (3);
First driving means (7) for turning the wheel (W) around the first kingpin axis (4);
Second driving means (M) for turning the wheel (W) around the second kingpin axis (5);
A steering apparatus comprising:   The steering apparatus according to claim 1, further comprising a lock mechanism (8) for fixing rotation of the wheel (W) around the second kingpin shaft (5).   The rotation of the knuckle (3) around the first kingpin shaft (4) is performed in accordance with the turning operation of the wheel (W), while the rotation around the second kingpin shaft (5) is performed. The steering apparatus according to claim 1 or 2, wherein the wheel (W) is rotated in accordance with an operation for changing a travel mode of the vehicle (C).   The first kingpin shaft (4) and the second kingpin shaft (5) and the second kingpin shaft (5) have a scrub radius (r2) larger than a scrub radius (r1) of the first kingpin shaft (4). The steering apparatus according to claim 3, wherein two kingpin shafts (5) are arranged.   The second drive means (M) for turning the wheel (W) around the second kingpin shaft (5) is an in-wheel motor (M), a hydraulic cylinder, a pneumatic cylinder, an electric cylinder, a motor, The steering apparatus according to any one of claims 1 to 4, comprising a power source such as a speed reducer.   The knuckle (3) provided on the chassis via the suspension device (2) is attached to at least one of the front and rear wheels (W), and the knuckle (3) is rotated in the turning direction with respect to the suspension device (2). A first kingpin shaft (4) to be moved, and a second kingpin shaft (5) for rotating the wheel (W) in a direction corresponding to a travel mode of the vehicle (C) with respect to the knuckle (3). When the travel mode of the vehicle (C) is changed by the steering device (1), the front or rear wheel (W) is moved to the second kingpin shaft ( 5) A vehicle driving mode switching method that prevents the vehicle (C) from moving during the switching of the traveling mode while rotating around and preventing the other wheel (W) from rotating.   A knuckle (3) provided on the chassis via a suspension device (2) on the front and rear wheels (W), and a knuckle (3) for rotating the knuckle (3) in the turning direction with respect to the suspension device (2) One kingpin shaft (4), and a second kingpin shaft (5) for rotating the wheel (W) in a direction corresponding to a traveling mode of the vehicle (C) with respect to the knuckle (3). When the steering device (1) is provided and the traveling mode of the vehicle (C) is changed by the steering device (1), both the front and rear wheels (W) are rotated around the second kingpin shaft (5). A method for switching the travel mode of the vehicle so that the vehicle (C) does not move during the switching of the travel mode.

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