JP2017007575A - Steering device, and vehicle having steering device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure safety of a traveling state of a vehicle having a special travel mode such as a mode of steering left and right wheels in left and right opposite directions.SOLUTION: A steering device comprises a steering mechanism 20 capable of steering left and right wheels in left and right opposite directions, and a plurality of lock mechanisms 50 for preventing actuation of the steering mechanism 20 by inputs from the wheels W. Even when a failure occurs to one of the lock mechanisms 50, a lock function is exerted by the other lock mechanism 50. Thus, the left and right wheels W are prevented from being steered unexpectedly by resistance received by the wheels W from a road surface, thereby ensuring a stable traveling state.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a steering device and a vehicle including the steering device, and in particular, a plurality of switches that enable switching to a special traveling mode in which left and right wheels are steered in opposite directions and prevent reverse input from the wheels. It is related with the thing provided with the lock mechanism.

  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 uses a tie rod and a knuckle arm, and is configured such that the left and right wheels have the same turning center when the vehicle turns.

  According to this steering device, during normal traveling, 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 turning of the vehicle, so that smooth traveling is possible. However, in special driving modes such as lateral movement of the vehicle (transverse movement in the lateral direction with the vehicle facing in the front-rear direction), the wheels need to be steered greatly (in the case of lateral movement, It is necessary to steer the wheel in a direction of 90 degrees with respect to the front-rear direction), and such steering is often difficult due to the length of the steering link and interference with other members. In addition, in a steering device that can greatly steer left and right wheels, it is necessary to ensure sufficient running stability by preventing the left and right wheels from being inadvertently steered by the resistance that the wheels receive from the road surface. .

  Therefore, for example, the steering device according to Patent Document 1 employs a configuration in which a steering link mechanism for left and right wheels using tie rods and knuckle arms is employed for at least one of the front and rear wheels. In this configuration, the length of the tie rod, the distance between the left and right tie rods, or the angle formed by each wheel and the knuckle arm is changed by the actuator. When this steering device is used, it is possible to smoothly perform traveling such as normal traveling and parallel movement in an oblique direction, and excellent responsiveness can be obtained.

  In addition, the steering device according to Patent Document 2 is disposed between front and rear left and right wheels, and is interposed between a steering shaft that can rotate around an axis and a left and right divided steering shaft. And a forward / reverse switching mechanism that switches the rotation direction between forward and reverse directions. According to this configuration, various steering modes such as large turning and on-site rotation are possible without using complicated control of the actuator.

  In Patent Document 3, in the rear wheel steering apparatus, a restriction pin is provided in a pin receiving part formed on the rack shaft so as to be freely inserted and removed, and the rack pin is inserted into the pin receiving part so that the rack shaft is in a neutral position. The structure fixed with is adopted. By adopting this configuration, it is possible to prevent the rear wheels from being inadvertently turned and to ensure a stable traveling state.

Japanese Patent Laid-Open No. 04-262971 Japanese Patent No. 4635754 JP 2014-24536 A

  The configuration of Patent Document 1 includes an actuator that changes 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, so there is no space and a large turning angle of about 90 degrees. Has the problem of difficulty. In addition, the left and right actuators must perform not only the respective controls but also the control for ensuring the left and right balance, and there is a problem that the control becomes very complicated.

  Further, the structure of 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 steering shaft. For this reason, there is a problem that rattling is likely to occur and it is difficult to smoothly steer the wheels.

  Furthermore, in the configuration of Patent Document 3, the rack shaft is fixed at one central portion of the rack shaft. However, if the restriction pin comes off or is damaged due to some trouble, the rear wheel steering device is locked. There is a problem that the mechanism is damaged and the running state becomes unstable.

  Therefore, an object of the present invention is to ensure the stability of the traveling state of a vehicle having a special traveling mode such as turning left and right wheels in opposite directions.

  In order to solve the above-described problem, in the present invention, a steering mechanism capable of turning left and right wheels in opposite directions, and a plurality of mechanisms that prevent the steering mechanism from operating due to input from the wheels. And a steering device provided with the locking mechanism.

  In a steering mechanism that can steer left and right wheels in opposite directions, it is necessary to prevent the left and right wheels from being inadvertently steered by the resistance that the wheels receive from the road surface in order to ensure a stable running state. Thus, by adopting a configuration including a plurality of locking mechanisms, even if one locking mechanism is lost, the locking function by another locking mechanism is exhibited. For this reason, it is possible to prevent the left and right wheels from being inadvertently turned by the resistance that the wheels receive from the road surface, and to ensure a stable traveling state.

  In the above configuration, the steering mechanism is connected to the left and right wheels, the tie rods for turning the wheels to the left and right, the pair of special steering rack bars connected to the tie rods, and the pair of special wheels. A special turning pinion gear that meshes with each of the rudder rack bars and moves the special turning rack bar by the same distance in the left and right directions, and a driving force transmission mechanism that transmits the driving force of the motor to the special turning pinion gear side. A rack case that houses the pair of special steered rack bars, a moving mechanism that moves to the left and right based on the steering operation of the driver, and the moving mechanism and the rack case are coupled, A connecting member that moves the rack case to the left and right along with the movement to the left and right can be used.

  In this way, when the rack case that houses the special steered rack bar and the moving mechanism are connected by the connecting member, the driver performs the normal steer operation, so that the entire pair of special steered rack bars is bundled together. The left and right wheels can be steered in the same direction. On the other hand, the driver can move the pair of special steerable rack bars by the same distance in the opposite direction from each other by performing the switching operation of the travel mode without performing the normal steering operation. It can be switched to a special travel mode such as a travel mode.

  In the configuration employing the driving force transmission mechanism, the driving force transmission mechanism includes a worm provided coaxially with a motor shaft of the motor, and a worm wheel meshing with the worm, and the plurality of lock mechanisms. It can be set as the structure which functions as one of them.

  Depending on the design conditions of the worm and the worm wheel, the worm wheel can be easily rotated by the rotation of the worm, whereas the rotation of the worm wheel makes it difficult to rotate the worm. Therefore, by providing a worm on the motor shaft side, it is possible to transmit the rotational driving force of the motor to the steering mechanism side, but even if the rotational driving force acts on the worm wheel due to the resistance that the wheel receives from the road surface. The transmission (reverse input) of the rotational driving force to the motor shaft side can be cut off. For this reason, it is possible to prevent the wheels from being inadvertently steered during traveling and to ensure a stable traveling state.

  Further, in the configuration in which the special steered rack bar is moved left and right with the special steered pinion gear, a reverse input prevention clutch that functions as one of the plurality of lock mechanisms is provided coaxially with the special steered pinion gear. It can be set as the provided structure.

  Thus, by providing the reverse input prevention clutch, the reverse input from the steering mechanism side can be surely prevented, and the running stability of the vehicle can be further enhanced.

  In the configuration employing this reverse input prevention clutch, the reverse input prevention clutch has a flat surface on a part of the outer peripheral surface with a predetermined angular interval and a relatively short distance from the shaft center to the surface. A cam member formed with a cam surface, a clutch housing provided coaxially with the cam member on the outer diameter side of the cam member, and a rolling member provided between the cam member and the clutch housing. A pocket is formed at the same angular interval as the cam surface, and a holder that holds the rolling elements two by two in the pocket and rotates around the axis as the motor shaft rotates, and the pocket A structure may be provided that includes an urging member that is interposed between the two held rolling elements and urges the rolling elements in opposite directions.

  By configuring the reverse input prevention clutch in this way, it is possible to reliably prevent reverse input from the steered mechanism side with a simple configuration, and to further improve the running stability of the vehicle.

  The drive force transmission mechanism having a worm provided coaxially with the motor shaft of the motor and a worm wheel meshing with the worm functions as one of the plurality of lock mechanisms, while the outer peripheral surface A cam member formed with a flat cam surface at a predetermined angular interval and having a relatively short distance from the axis to the surface at a predetermined angular interval, and an outer diameter side of the cam member. A clutch housing provided coaxially with the cam member, a rolling element provided between the cam member and the clutch housing, and a pocket are formed at the same angular interval as the cam surface, and the pocket is formed in the pocket. Each rolling element is provided between each of the two rolling elements held by two holders each holding two rolling elements and rotating around the axis as the motor shaft rotates. A reverse input prevention clutch having biasing members biasing in opposite directions functions as another one of the plurality of lock mechanisms, and the worm wheel and the cam member are provided coaxially. It can also be.

  As described above, by providing the worm wheel and the cam member coaxially, it is possible to more reliably prevent the reverse input from the steering mechanism side. That is, in the driving force transmission mechanism (worm gear), the power transmission shafts of the worm and the worm wheel are in a twisted position of 90 degrees, whereas in the reverse input prevention clutch, the power transmission shafts of the cam member and the cage are It has a coaxial positional relationship.

  The steering device according to each of the above configurations is mounted on a vehicle. A vehicle equipped with this steering device can prevent the wheels from being inadvertently turned left and right by the resistance received from the road surface when the left and right wheels are turned in a special driving mode such as turning in the opposite direction. And high running stability can be ensured.

  In this invention, a steering mechanism comprising: a steering mechanism capable of turning left and right wheels in opposite directions; and a plurality of lock mechanisms that prevent the steering mechanism from being operated by input from the wheels. Configured the device. In this way, by adopting a configuration including a plurality of locking mechanisms, even if one locking mechanism fails, the locking function by another locking mechanism is exhibited. For this reason, it is possible to prevent the left and right wheels from being inadvertently turned by the resistance that the wheels receive from the road surface, and to ensure a stable traveling state.

Image of vehicle using steering apparatus according to the present invention FIG. 1 is a plan view showing the arrangement of the steering device according to the present invention on the vehicle shown in FIG. The perspective view of the steering device mounted in the vehicle shown in FIG. A longitudinal sectional view of a steering device according to the present invention Sectional drawing which follows the VV line in FIG. Sectional drawing which follows the VI-VI line in FIG. It is a longitudinal cross-sectional view which shows the effect | action of the reverse input prevention clutch shown in FIG. 6, Comprising: (a) is a standby state, (b) is the state which the lock | rock was cancelled | released, (c) is the state which the cam member rotated. FIG. 2 is a plan view showing a state where the vehicle shown in FIG. The top view which shows the state which made the vehicle shown in FIG. 2 the spot turn mode The top view which shows the state which made the vehicle shown in FIG. 2 the spot rotation mode FIG. 2 is a plan view showing a state where the vehicle shown in FIG. 2 is in a lateral movement mode.

  The overall configuration of the vehicle, the details of the steering device, and the travel mode of the vehicle according to the present invention will be sequentially described with reference to the drawings.

(1) About the whole structure of a vehicle, and the detail of a steering apparatus Steering apparatuses 10 and 11 (refer FIG. 2) which concern on this invention are employ | adopted for the vehicle 1 shown in FIG. 1, for example. This vehicle 1 is an ultra-compact mobility of two-seater (side-by-side two-seater). The driver can operate the steering wheel 2 to rotate the steering shaft 3 around the axis so that the wheel w can be steered in a desired direction. In addition, although the microminiature mobility was mentioned as an example in this figure, this steering apparatus 10 and 11 is applicable not only to a small vehicle but to various types of vehicles 1.

  As shown in FIG. 2, steering devices 10 and 11 are provided on the front and rear wheels w, respectively. On the front wheel side, the left and right wheels w are steered in the opposite directions, the special steering mechanism 20 for switching the vehicle 1 to a special travel mode such as a lateral movement mode, and the left and right wheels w in the normal travel mode. A steering apparatus 10 including both a normal steering mechanism 40 that steers in the same direction is employed. In this normal steering mechanism 40, an Ackermann-Jantou type mechanism is adopted around the undercarriage, and the vehicle 1 can be driven smoothly.

  On the other hand, on the rear wheel side, a steering device 11 having only a special turning mechanism 20 that switches the vehicle 1 to a special traveling mode is employed. Each wheel w of the vehicle 1 is provided with an in-wheel motor M, and the wheel w is rotationally driven by the driving force of the in-wheel motor M. As shown in this figure, instead of providing the in-wheel motor M on all four wheels, a configuration may be adopted in which the in-wheel motor M is provided only on the front or rear two wheels. In FIG. 2, the direction indicated by the left-pointing white arrow is the straight traveling direction when the vehicle 1 is traveling normally. The same applies to FIGS. 8 to 11 described later.

  A steering device 10 provided on the front wheel side of the vehicle 1 will be described with reference to FIGS. 3 is a perspective view of the steering apparatus 10 as a whole, FIG. 4 is a longitudinal sectional view showing a gear configuration, FIG. 5 is a sectional view taken along line VV in FIG. 4, and FIG. 6 is taken along line VI-VI in FIG. It is sectional drawing which follows.

  As shown in FIG. 4 and the like, the special turning mechanism 20 includes left and right tie rods 21, a pair of special turning rack bars 22, 23, a special turning pinion gear 24, a motor gear 25, and a rack case 26. It is a member. The tie rod 21 is a member that is connected to the left and right wheels w and steers the wheels w to the left and right. A pair of special steerable rack bars 22 and 23 are connected to the left and right tie rods 21 and 21, respectively. In the following, the special turning rack bar 22 for turning the left wheel w with respect to the front-rear direction of the vehicle 1 is the first rack bar 22 and the special turning rack bar 23 for turning the right wheel w is the second. These will be referred to as rack bars 23, respectively. The first rack bar 22 and the second rack bar 23 are arranged in parallel to each other. In addition, in this figure, description of the motor 27 and the reduction gear 28 (refer FIG. 3) is abbreviate | omitted.

  The pair of specially steered rack bars 22 and 23 (first rack bar 22 and second rack bar 23) are housed in a rack case 26 so that the rack case 26 can protrude freely left and right around the rack case 26. It has become. The rack case 26 is not directly fixed to the frame (not shown) of the vehicle 1, and is connected to a connecting member 41 provided in the normal steering mechanism 40 described later. It is supported. Then, as the connecting member 41 moves to the left and right, the entire special steering mechanism 20 moves to the left and right.

  Two special turning pinion gears 24 are provided in parallel between the first rack bar 22 and the second rack bar 23 so as to be parallel in the moving direction of the rack bars 22 and 23. Both special steered pinion gears 24, 24 and both rack bars 22, 23 mesh with each other. The number of teeth of the two special turning pinion gears 24, 24 is the same. A motor gear 25 driven by a motor 27 (see FIG. 3) is disposed between the two special steered pinion gears 24 and 24. A reduction gear 28 is provided on the output shaft side of the motor 27 (see FIG. 3), and the rotation of the motor 27 is transmitted to the motor gear 25 after being decelerated by the reduction gear 28.

  A synchronous gear 29 is provided between the motor gear 25 and the two special steered pinion gears 24 and 24, respectively. The two synchronous gears 29 and 29 have the same number of teeth. When the motor 27 is driven to rotate the motor gear 25 about the axis, the driving force is transmitted to the special steered pinion gear 24 via the synchronous gear 29. Since the number of teeth of the two special steered pinion gears 24 and 24 and the number of teeth of the two synchronous gears 29 and 29 are both the same, the rotation of the motor gear 25 around the axis causes the first rack The bar 22 and the second rack bar 23 can be moved the same distance in the opposite directions.

  As described above, the motor gear 25 is disposed between the two special turning pinion gears 24 and 24 and is driven by the single motor 27, so that the pair of gears driven by the special turning pinion gear 24 can be driven. The special steerable rack bars 22 and 23 can be completely synchronized. For this reason, each wheel w can be accurately steered to the turning angle corresponding to each special traveling mode, and the traveling state in each special traveling mode can be stabilized.

  Further, by arranging a plurality of special steered pinion gears 24 in the moving direction of the two special steered rack bars (first rack bar 22 and second rack bar 23), the special steered rack bars 22 and 23 are moved to the left and right. Even if it moves to any position in the direction, it can always be engaged with at least one of the special steered pinion gears 24, and in order to ensure this meshing, the total length of the special steered rack bars 22 and 23 is increased. There is no need. For this reason, the special steering mechanism 20 can be reduced in size.

  Furthermore, by increasing the number of teeth of the special steered pinion gear 24 compared to the number of teeth of the motor gear 25, the rotational speed can be reduced and the rotational torque can be increased. For this reason, drive sources, such as the motor 27, can be reduced in size.

  The pair of special steerable rack bars 22 and 23 are provided with retractable protective covers 30 and 30. The stretchable protective cover 30 prevents rainwater, mud, or the like from entering the special turning mechanism 20 or the grease inside the special turning mechanism 20 from being scattered outside.

  The normal turning mechanism 40 includes a normal turning pinion gear 42 and a normal turning rack bar 43 as main components. As shown in FIG. 3, the normal steering pinion gear 42 is connected to the steering shaft 3 that rotates around the axis together with the steering 2 (see FIG. 2), and rotates around the axis based on the steering operation of the driver. To do.

  The normal turning rack bar 43 is meshed with the normal turning pinion gear 42. As the normal turning pinion gear 42 rotates about the axis, the normal turning rack bar 43 moves to the left and right. As shown in FIG. 4, the normal steered rack bar 43 is housed in a rack case 44. The rack case 44 is provided with a vehicle body fixing portion (not shown) in which a bolt hole is formed, and is fixed to the frame of the vehicle 1 by a fixing member such as a bolt provided in the bolt hole.

  The normal turning rack bar 43 is integrally provided with a connecting member 41, and the connecting member 41 connects the normal turning rack bar 43 and the rack case 26 of the special turning mechanism 20 (FIG. 4). reference). When the normal steering rack bar 43 is moved left and right by the steering operation of the driver, the entire special steering mechanism 20 moves left and right, and the left and right wheels w can be steered in the same direction.

  The normal steerable rack bar 43 is provided with a retractable protective cover 45. The retractable protective cover 45 prevents rainwater, mud, etc. from entering the normal steering mechanism 40 and the grease inside the normal steering mechanism 40 from being scattered outside.

  The steering device 11 provided on the rear wheel side of the vehicle 1 is different from the steering device 10 provided on the front wheel side in that it does not normally include the steering mechanism 40, but the other configurations are the same. Note that the front-wheel side steering device 10 including both the special steering mechanism 20 and the normal steering mechanism 40 has the rack case 44 of the normal steering mechanism 40 fixed to the frame of the vehicle 1 as described above. Thus, the special steering mechanism 20 that moves to the left and right integrally with the normal steering mechanism 40 is not fixed to the frame. On the other hand, the rear-wheel-side steering device 11 that employs only the special steering mechanism 20 fixes the rack case 26 and the like of the special steering mechanism 20 to the frame.

  The steering devices 10 and 11 provided on the front and rear wheels are provided with two types of lock mechanisms 50 and 50, respectively. The lock mechanism 50 will be described with reference to FIG.

  The first locking mechanism 50a includes a worm 51 provided coaxially with the motor shaft 27a of the motor 27 (see FIG. 3), and a worm wheel 53 provided coaxially with the shaft 52 constituting the driving force transmission mechanism. Consists of worm gear. The worm 51 and the worm wheel 53 are meshed with each other, and the worm 51 rotates as the motor shaft 27a rotates about the axis, and the worm wheel 53 rotates about the axis by the rotational driving force. The shaft 52 is supported by motor housings 55a and 55b via bearings 54. Depending on the design conditions of the worm 51 and the worm wheel 53, the rotational driving force can be easily transmitted from the worm 51 to the worm wheel 53, but it is difficult to rotate the worm 51 by the rotation of the worm wheel 53. become.

  As shown in FIG. 5, by providing the worm 51 on the motor shaft 27a side, the rotational driving force of the motor 27 can be transmitted to the wheel w side, while the worm wheel 53 is caused by the resistance that the wheel w receives from the road surface. Even if a rotational driving force is applied to the motor shaft, transmission (reverse input) of the rotational driving force to the motor shaft 27a can be blocked. For this reason, it is prevented that the wheels w are inadvertently steered during traveling, and a stable traveling state can be ensured. In this configuration, by making the torsion angle of the worm 51 smaller than the repose angle (friction angle), the reverse input can be blocked more reliably.

  The second lock mechanism 50 b is configured by a reverse input prevention clutch provided in the motor gear 25. As shown in FIG. 6, the reverse input preventing clutch includes a cam member 61, a clutch housing 62, a rolling element 63, a retainer 64, and an urging member 65 as main components.

  On the outer peripheral surface of the cam member 61, a cam surface 61 a made of a flat surface is formed at a predetermined angular interval and the distance from the axis to the surface is relatively shorter than other portions. Further, through holes 66 are formed in the side surface (surface perpendicular to the paper surface) of the cam member 61 at a predetermined interval (60 ° interval around the rotation axis in this embodiment). The clutch housing 62 is provided coaxially with the cam member 61 on the outer diameter side of the cam member 61. A plurality of rollers are provided as rolling elements 63 between the cam member 61 and the clutch housing 62. Pockets are formed in the retainer 64 at the same angular intervals as the cam surface 61a, and two rolling elements 63 are accommodated in each pocket. The cage 64 extends in the axial direction of the motor gear 25, and a cage projection 67 at the tip is inserted into the through hole 66 of the cam member 61. The cage protrusion 67 has a columnar shape, and the outer diameter thereof is smaller than the inner diameter of the through hole 66. For this reason, a gap is formed between the inner diameter surface of the through-hole 66 and the cage protrusion 67 (see FIG. 6).

  The retainer 64 rotates around the shaft in response to the rotational driving force generated by the rotation of the motor shaft 27a, coaxially and integrally with the shaft 52. The urging member 65 is provided between the two rolling elements 63 and 63 housed in the pocket, and urges the rolling elements 63 and 63 in opposite directions. In this configuration, the worm wheel 53 of the first lock mechanism 50a and the cam member 61 of the second lock mechanism 50b are provided coaxially.

  The operation of the reverse input preventing clutch will be described with reference to FIG. When no rotational driving force is applied from either the motor shaft 27 a side (see FIG. 5) or the steering mechanism side, the two rolling elements 63 a and 63 b are driven by the urging force of the urging member 65. The cam surface 61a meshes with both the inner surface of the clutch housing 62 and the relative rotation between the cam member 61 and the clutch housing 62 is lightly locked (standby state). At this time, a gap exists between the inner diameter surface of the through-hole 66 and the cage protrusion 67 (see FIG. 5A).

  Here, when a rotational driving force is applied to the motor shaft 27a (see FIG. 5) and the shaft 52 is rotated in the clockwise direction around the shaft, the retainer 64 rotates integrally with the shaft 52 (in FIG. 5B). See the white arrow). When the cage 64 is rotated, the rolling element 63a at the rear in the rotational direction is pushed by the cage 64 in the rotational direction. This pushed direction is a direction in which the gap between the cam surface 61a and the inner surface of the clutch housing 62 is widened, so that the engagement between the rolling element 63a and the cam surface 61a of the cam member 61 and the inner surface of the clutch housing 62 is reduced. The locked state between the cam member 61 and the clutch housing 62 is released. The retainer protrusion 67 also rotates in the same direction and at the same angle as the retainer 64 rotates, but at the time of unlocking, there is still a slight gap between the inner diameter surface of the through-hole 66 and the retainer protrusion 67. Exists (see FIG. 4B).

  When the cage 64 (shaft 52) continues to rotate in the same direction (see the white arrow in this figure (c)), the inner diameter surface of the through-hole 66 and the cage projection 67 come into contact with each other, and this cage projection A rotational driving force is transmitted to the cam member 61 (and the motor gear 25) side via 67 (see the black arrow in FIG. 6C). Accordingly, the rotational driving force is sequentially transmitted from the motor shaft 27a (see FIG. 5) to the shaft 52, the cage 64, the cage projection 67, the cam member 61, and the motor gear 25. The cam member 61 and the motor gear 25 are coupled so as to rotate integrally by spline fitting or serration fitting. When a rotational driving force in the opposite direction, that is, in the counterclockwise direction is applied, the rolling element 63b at the rear in the rotational direction is pushed in the rotational direction by the cage 64, and the rolling element 63b, the cam surface 61a of the cam member 61, and the clutch Engagement with the inner surface of the housing 62 is reduced, the locked state between the cam member 61 and the clutch housing 62 is released, and the rotational driving force is transmitted.

  On the other hand, in the standby state shown in FIG. 7A, in the state where the rotational driving force is not acting from the motor shaft 27a (see FIG. 5) side, from the steering mechanism (motor gear 25) side in the clockwise direction. When the rotational driving force is applied, the cam member 61 is rotated in the clockwise direction around the axis by the rotational driving force. For example, when the cam member 61 rotates in the direction indicated by the black arrow in FIG. 7C and the cam surface 61a is inclined in that direction, the rolling element 63a at the rear in the rotation direction is changed to the cam surface 61a of the cam member 61 and Both the inner surfaces of the clutch housing 62 are strongly engaged, and the relative rotation between the cam member 61 and the clutch housing 62 is completely locked. Thereby, the reverse input blocking action from the steering mechanism side is exhibited. When a rotational driving force is applied in the counterclockwise direction from the steering mechanism (motor gear 25) side, the rolling element 63b at the rear in the rotational direction is strongly engaged, and the relative rotation between the cam member 61 and the clutch housing 62 is completely locked. The

  Note that the worm gear and the reverse input prevention clutch employed as the lock mechanism 50 (50a, 50b) in this embodiment are merely examples, and other lock mechanisms 50 may be employed as long as reverse input can be prevented. it can. Also, the same type of locking mechanism 50 can be used in combination.

(2) Vehicle Travel Modes Hereinafter, the main travel modes (normal travel mode, spot turn mode, spot turn mode, lateral movement mode) of the vehicle 1 described in the above item (1) will be described with reference to FIG. Will be described with reference to FIG. Switching between the travel modes is performed, for example, by operating travel mode switching means (not shown) provided in the vicinity of the driver's seat.

(Normal driving mode)
FIG. 8 shows a state where the vehicle 1 shown in FIG. 2 is in the normal travel mode. The normal travel mode is a mode in which the front wheels are steered in the same direction in the left and right during normal travel, as in a normal vehicle. FIG. 8 shows a state in which the left and right front wheels are steered in the right direction. When the driver operates the steering wheel 2 and rotates the normal steering pinion gear 42 of the steering device 10 on the front wheel side around the axis, the normal steering rack bar 43 constituting the normal steering mechanism 40 is associated with this rotation. (See FIG. 4) moves in one direction (the left side of the vehicle 1 in FIG. 8). Along with this movement, the special turning mechanism 20 connected to the normal turning rack bar 43 also moves in the left-right direction (the left side of the vehicle 1 in FIG. 8) together with the normal turning rack bar 43. At this time, the steering device 11 on the rear wheel side is always in a neutral state that does not steer in either the left or right direction.

  In this normal travel mode, the normal steering rack bar 43 of the normal steering mechanism 40 is moved to the left and right by the steering operation by the driver, and the front wheels can be steered to the left and right in the same manner as in a normal vehicle. On the other hand, the special steering mechanisms 20 of both the front wheel side and rear wheel side steering devices 10, 11 are locked by the lock mechanisms 50 (50a, 50b). For this reason, it is possible to prevent the traveling stability of the vehicle 1 from being impaired due to the special turning mechanism 20 being inadvertently operated by reverse input from the wheels w during normal traveling.

(Spot turn mode)
FIG. 9 shows a state where the vehicle 1 shown in FIG. The spot turn mode is a mode in which the direction of the vehicle 1 is changed at substantially the same position. In the in-situ turning mode, the left and right rear wheels are moved left and right by the special turning mechanism 20 of the steering device 11 on the rear wheel side while the front wheels are made to go straight by the normal turning mechanism 40 of the steering device 10 on the front wheel side. The vehicle is steered so as to face the center point of the front wheel (see reference numeral C1 in FIG. 9). At this time, the normal steering mechanism 40 of the steering device 10 on the front wheel side is maintained by the driver holding the steering 2 or by operating an actuator (not shown) provided in the normal steering mechanism 40. Fixed. On the other hand, the special steering mechanisms 20 of both the front wheel side and rear wheel side steering devices 10, 11 are locked by the lock mechanisms 50 (50a, 50b).

  In this state, when the in-wheel motor M provided on the rear wheel is driven, the vehicle 1 turns with the center point C1 as the turning center. By providing the locking mechanisms 50 (50a, 50b) on the front and rear wheel steering devices 10, 11, it is possible to prevent the turning center from deviating from the center point C1 during turning of the vehicle 1 and thus making the turning state unstable. can do.

(In-situ rotation mode)
FIG. 10 shows a state where the vehicle 1 shown in FIG. The spot rotation mode is a mode in which the direction of the vehicle 1 is changed at the same position. In the in-situ rotation mode, the front wheel is made straight by the normal steering mechanism 40 of the front wheel side steering device 10, and then the special steering mechanism 20 of the front wheel side and rear wheel side steering devices 10, 11 is used. The left and right front and rear wheels are steered so as to face the center point of the vehicle 1 (see C2 in FIG. 10). At this time, the normal steering mechanism 40 of the steering device 10 on the front wheel side is maintained by the driver holding the steering 2 or by operating an actuator (not shown) provided in the normal steering mechanism 40. Fixed. On the other hand, the special steering mechanisms 20 of both the front wheel side and rear wheel side steering devices 10, 11 are locked by the lock mechanisms 50 (50a, 50b).

  When at least one of the in-wheel motors M provided on the front and rear wheels is driven in this state, the vehicle 1 rotates around the center point C2. By providing the locking mechanisms 50 (50a, 50b) on the front and rear wheel steering devices 10, 11, it is possible to prevent the rotational state from deviating from the center point C2 during rotation of the vehicle 1 and causing the rotational state to become unstable. can do.

(Lateral movement mode)
FIG. 11 shows a state in which the vehicle 1 shown in FIG. 2 is in the lateral movement mode. The lateral movement mode is a mode in which the vehicle 1 is moved in a direction orthogonal to the straight direction of the vehicle 1 by 90 degrees with the vehicle 1 facing forward. In the lateral movement mode, the normal steering mechanism 40 of the steering device 10 on the front wheel side makes the front wheels straight, and then the special steering mechanism 20 of the steering devices 10 and 11 on the front wheel side and the rear wheel side The left and right front and rear wheels are steered in a direction orthogonal to the straight direction of the vehicle 1 by 90 degrees. At this time, the normal steering mechanism 40 of the steering device 10 on the front wheel side is maintained by the driver holding the steering 2 or by operating an actuator (not shown) provided in the normal steering mechanism 40. Fixed. On the other hand, the special steering mechanisms 20 of both the front wheel side and rear wheel side steering devices 10, 11 are locked by the lock mechanisms 50 (50a, 50b).

  In this state, when at least one of the in-wheel motors M provided on the front and rear wheels is driven, the vehicle 1 can be moved in the lateral direction. By providing the locking mechanisms 50 (50a, 50b) on the front and rear wheel steering devices 10, 11, the special steering mechanism 20 is inadvertently caused by reverse input from the wheels while the vehicle 1 is moving in the lateral direction. Acting can prevent the running stability of the vehicle from being impaired. In addition, when the driver operates the steering wheel 2 during the movement in the lateral direction, the normal turning mechanism 40 is unlocked, and the traveling direction of the vehicle can be adjusted.

  In the present invention, a special turning mechanism 20 capable of turning the left and right wheels w in the left and right reverse directions, a plurality of lock mechanisms 50 that prevent the special turning mechanism 20 from being activated by input from the wheels w, Steering devices 10 and 11 having the above are configured. According to the steering devices 10 and 11, the lock mechanism 50 can prevent the special steering mechanism 20 from inadvertently operating and ensure the stability of the traveling state.

  Note that the above-described embodiment is merely an example, and it is an object of the present invention to ensure the stability of the traveling state of the vehicle 1 having a special traveling mode such as turning the left and right wheels w in opposite directions. As long as the above can be solved, it is allowed to appropriately change the shape and arrangement of the members constituting the steering devices 10 and 11.

DESCRIPTION OF SYMBOLS 1 Vehicle 2 Steering 3 Steering shaft 10 (front wheel side) steering device 11 (rear wheel side) steering device 20 Special turning mechanism (steering mechanism)
21 Tie rod 22 First rack bar (special steering rack bar)
23 Second rack bar (special steering rack bar)
24 Special steered pinion gear 25 Motor gear 26 Rack case 27 Motor 27a Motor shaft 28 Reducer 29 Synchronous gear 30 Protective cover 40 Normal steered mechanism (moving mechanism)
41 connecting member 42 normal turning pinion gear 43 normal turning rack bar 44 rack case 45 protective cover 50 lock mechanism 50a first lock mechanism 50b second lock mechanism 51 worm 52 shaft 53 worm wheel 54 bearings 55a and 55b motor housing 61 Cam member 61a Cam surface 62 Clutch housing 63 (63a, 63b) Rolling body 64 Cage 65 Energizing member 66 Through hole 67 Cage protrusion w Wheel M In-wheel motor

Claims (7)

A steering mechanism (20) capable of steering the left and right wheels (w) in opposite directions;
A plurality of locking mechanisms (50) for preventing the steering mechanism (20) from being activated by input from the wheels (w);
Steering device with   The steering mechanism (20) is connected to the left and right wheels (w), and the pair of special wheels connected to the tie rod (21) and the tie rod (21) that steers the wheel (w) to the left and right. A special rack wheel (22, 23) and a special steering rack bar (22, 23) engaged with each of the pair of special steering rack bars (22, 23) and moving the special steering rack bar (22, 23) by the same distance in the opposite left and right directions. A turning pinion gear (24), a driving force transmission mechanism for transmitting the driving force of the motor (27) to the special turning pinion gear (24) side, and the pair of special turning rack bars (22, 23) A rack case (26) to be housed, a moving mechanism (40) that moves to the left and right based on a steering operation by the driver, and the moving mechanism (40) and the rack case (26) are connected to each other, and the moving mechanism (40) move left and right , The steering apparatus according to claim 1 having a coupling member (41) for moving the rack case (26) to the left and right.   The driving force transmission mechanism includes a worm (51) provided coaxially with a motor shaft (27a) of the motor (27), and a worm wheel (53) meshing with the worm (51), The steering apparatus according to claim 2, which functions as one of the locking mechanisms (50).   The steering apparatus according to claim 2 or 3, wherein a reverse input prevention clutch that functions as one of the plurality of lock mechanisms (50) is provided coaxially with the special turning pinion gear (24).   A cam member in which the reverse input prevention clutch forms a cam surface (61a) having a flat surface on a part of the outer peripheral surface at a predetermined angular interval and having a relatively short distance from the shaft center to the surface. (61), a clutch housing (62) provided coaxially with the cam member (61) on the outer diameter side of the cam member (61), the cam member (61) and the clutch housing (62) And a pocket is formed at the same angular interval as the cam surface (61a), and the two rolling elements (63) are held in the pocket two by one. Each rolling element is provided between a cage (64) that rotates around the axis with the rotation of the axis (27a) and the two rolling elements (63, 63) held in the pocket. (63, 63) are urged in opposite directions to each other Energizing member (65) and the steering device according to claim 4 having a. The drive force transmission mechanism having a worm (51) provided coaxially with a motor shaft (27a) of the motor (27) and a worm wheel (53) meshing with the worm (51) includes the plurality of lock mechanisms. While functioning as one of (50),
A cam member (61) having a cam surface (61a) formed of a flat surface on a part of the outer peripheral surface at a predetermined angular interval and having a relatively short distance from the shaft center to the surface, compared to other locations; Provided on the outer diameter side of the member (61) is a clutch housing (62) provided coaxially with the cam member (61) and interposed between the cam member (61) and the clutch housing (62). A pocket is formed at the same angular interval as the rolling element (63) and the cam surface (61a), and two of the rolling elements (63) are held in the pocket to rotate the motor shaft (27a). Along with this, the cage (64) that rotates around the axis and the two rolling elements (63, 63) held in the pocket are provided between the rolling elements (63, 63). And a biasing member (65) for biasing in the reverse direction. Input prevention clutch functions as another one of the plurality of locking mechanisms (50),
The steering device according to claim 2, wherein the worm wheel (53) and the cam member (61) are provided coaxially.   A vehicle employing the steering device according to any one of claims 1 to 6.

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