JP2016094156A - Steering device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate a variation in internal pressure of a steering device accompanying steering to improve durability of an extension member and move smoothly rack bars.SOLUTION: The steering device is provided with extension members 70 which extend accompanying movements of a pair of rack bars 53 and 54 while wholly covering rack bars 53 and 54. When the pair of rack bars 53 and 54 are brought from an approached state into an opened state so that inner volumes of the extension members 70 are increased, air corresponding to the increased inner volumes is suctioned through an outside air port 72 into inside the extension members 70. While, when the pair of rack bars 53 and 54 are brought from the opened state into the approached state so that the inner volumes of the extension members 70 are decreased, air corresponding to the decreased inner volumes is exhausted through the outside air port 72 to the outside of the extension members 70.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a steering device that steers either a front wheel or a rear wheel, in particular, a steering device that includes a four-wheel steering mechanism, and relates to a steering device that includes a mechanism that eliminates a change in internal pressure of the steering device that accompanies steering.

  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 mechanism called. 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.

  There is also a steering mechanism provided with an actuator that changes either 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. According to this steering mechanism, all of normal traveling, parallel movement, and small traveling can be smoothly performed, and the response is excellent (see, for example, Patent Document 1).

  Further, the steering mechanism is arranged between the left and right wheels of the front and rear wheels, and includes a rack bar that is rotatable about an axis and divided into left and right, and a forward / reverse switching means between the two divided rack bars. There is. The forward / reverse switching means can transmit the rotation of one of the divided rack bars to the other in the forward / reverse direction. According to this steering mechanism, movements such as a steering angle of 90 degrees and lateral movement are possible (for example, see Patent Document 2).

  There is 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 (see, for example, Patent Document 3). There is also a steering mechanism in which traveling stability is improved by adjusting toe of the left and right wheels by moving a rack housing connecting the left and right wheels in the front-rear direction (see, for example, Patent Document 4).

  In addition, it has two rack bars that can move independently on the left and right, and each of the rack bars is connected to one of the left and right wheels via a tie rod, and the rack bar is connected by a synchronous gear held in a synchronous gear box. There is also a steering mechanism that can move the same distance symmetrically with respect to the synchronous gearbox (see Patent Document 5).

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 2013-200188 (unpublished)

  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.

  Further, in this type of vehicle, the front wheels that are main steered wheels can be steered in a predetermined traveling direction of the vehicle, and the rear wheels that are follower steered wheels are set in parallel with the longitudinal direction of the vehicle. ing. For this reason, when the front wheel of this vehicle is steered and turned, the front wheel and the rear wheel do not coincide with the turning circle. Therefore, at low vehicle speeds, the vehicle turns in a posture in which the rear wheels enter the inside of the turning circle due to the inner wheel difference, and at high vehicle speeds, the vehicle turns in a posture in which the front wheels enter the inside of the turning circle by centrifugal force. That is, there is a problem that even if the front wheels are steered in the turning direction, which is the traveling direction of the vehicle, the vehicle posture cannot be made to match the turning direction. Therefore, there is a vehicle having a four-wheel steering mechanism (four-wheel steering device) that improves not only the front wheels but also the rear wheels to improve traveling performance.

  As a vehicle having a four-wheel steering mechanism (a so-called 4WS vehicle), for example, in the technique described in Patent Document 1, it is possible to move the vehicle in the lateral direction, make a small turn, 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. 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.

  Patent Document 3 is an example of a conventional four-wheel steering mechanism. Although the rear wheel can be steered, it is difficult to move in the lateral direction with this mechanism alone for the same reason described above. Further, although Patent Document 4 can perform toe adjustment, it cannot cope with a lateral movement or a small turn of the vehicle.

  Patent Document 5 is devised by the applicant, solves the above-mentioned problems of Patent Documents 1 to 4, and has no problem with a basic four-wheel steering mechanism. However, unlike a steering device used in a general vehicle, there may be a problem caused by moving the pair of rack bars in the opposite direction. That is, this type of steering device is provided with an elastic member such as a boot in order to prevent the entry of foreign matter such as water and dust from the outside and the outflow of internal grease, and the pair of rack bars is sealed by this elastic member. It is in the state. For example, when the pair of rack bars move away from each other in the opposite direction, the expansion / contraction member extends and the internal volume of the expansion / contraction member (steering device) increases. As the internal volume increases, the internal pressure of the expansion / contraction member decreases, and the expansion / contraction member is deformed (collapsed). Due to this deformation, there is a problem that the elastic member is damaged due to contact with the rack bar inside the elastic member and its peripheral members. Further, since the rack bar movement resistance due to the change in the internal pressure is generated, it is necessary to move the rack bar against the movement resistance, which causes a problem of reducing the fuel consumption of the vehicle. This change in the internal pressure of the expansion / contraction member also occurs when the pair of rack bars move in opposite directions so as to approach each other.

  Accordingly, an object of the present invention is to eliminate the change in the internal pressure of the steering device that accompanies turning, improve the durability of the expansion and contraction member, and smoothly move the rack bar.

  In order to solve the above problems, in the present invention, tie rods connected to the left and right wheels of the front wheel or rear wheel and steering the left and right wheels, and a pair of rack bars respectively connected to the tie rods of the left and right wheels A synchronous gear that meshes with each of the pair of rack bars and converts the movement of the rack teeth of one rack bar in one direction relative to the parallel direction to the movement of the other rack bar in the other direction, and the pair of racks The rack bar operating means capable of moving the bar in the opposite direction along the parallel direction of the rack teeth of each rack bar, and the movement of the rack bar while covering the entire pair of rack bars. And a telescopic member that expands and contracts, and an outside air port that communicates air inside and outside the telescopic member.

  When the pair of rack bars move in the opposite direction so as to be separated from each other, the elastic member is in an extended state, and its internal volume increases. In this case, an amount of air corresponding to the increased internal volume is sucked into the elastic member through the outside air port. For this reason, the internal pressure can be kept almost constant, and due to the decrease in the internal pressure accompanying the increase in the internal volume, the expansion / contraction member collapses (dents) and contacts the rack bar and its peripheral members, causing damage. Can be prevented.

  Further, when the pair of rack bars move in the opposite direction so as to approach each other, the elastic member is contracted, and the internal volume is reduced. In this case, an amount of air corresponding to the reduced internal volume is discharged to the outside of the expansion / contraction member through the outside air port. For this reason, it is possible to keep the internal pressure almost constant as described above, and prevent the expansion / contraction member from expanding and contacting the peripheral member due to the increase in the internal pressure accompanying the decrease in the internal volume, and being damaged. Can do.

  As described above, with the movement of the pair of rack bars in the opposite direction, the air inside the expansion / contraction member can be freely taken in and out through the outside air port, so that the change in the internal pressure of the expansion / contraction member is the resistance to the movement of the rack bar. The rack bar can be moved smoothly. For this reason, the fuel consumption improvement of a vehicle can be aimed at.

  Such movement of the pair of rack bars in the reverse direction can be easily realized by providing a synchronous gear so as to be interposed between both rack bars. By enabling the movement in the reverse direction, it is possible to easily switch the traveling mode between the normal traveling mode and the special traveling mode such as spot rotation and small turn.

  In the above configuration, it further includes an opening facing the outside of the vehicle, a ventilation member that connects the opening and the outside air port and allows air to pass therethrough, and has a height from the ground to the opening, The height from the ground to the outside air port is preferably at least twice as high.

  If this height is less than twice, foreign substances such as rainwater and muddy water are likely to enter from the opening, but the entry can be reliably prevented by making this height at least twice.

  In each of the above-mentioned configurations, it is preferable to provide a blocking member for stopping the foreign matter flowing in the flow path while allowing the air flow in the flow path of the air passing through the outside air port.

  By providing the blocking member, it is possible to reliably prevent foreign matters such as rainwater and muddy water from entering the expansion member through the outside air port while allowing the air to flow.

  In this invention, each of the tie rods connected to the left and right wheels of the front wheel or the rear wheel to steer the left and right wheels, the pair of rack bars connected to the tie rods of the left and right wheels, and the pair of rack bars, respectively. A synchronous gear that meshes and converts the movement of one rack bar in one direction with respect to the parallel direction of the rack teeth into the other direction of the other rack bar, and the pair of rack bars is connected to the rack of each rack bar. Rack bar operating means capable of moving in the opposite direction along the teeth parallel direction, an elastic member that covers the entire pair of rack bars and expands and contracts as the rack bar moves, and the expansion and contraction The steering device has an outside air port that communicates air inside and outside the member.

  By configuring the steering device in this way, even if the expansion / contraction member expands / contracts with the turning and the internal volume increases / decreases, the amount of air corresponding to the increased / decreased internal volume expands / contracts through the outside air port. It can be made to go in and out of the member. For this reason, the internal pressure of the expansion / contraction member can be kept substantially constant, and the expansion / contraction member is prevented from being crushed (dented) or swelled due to a change in the internal pressure to come into contact with peripheral members and break. be able to. For this reason, durability of an expansion-contraction member can be improved significantly. In addition, the rack bar can be moved smoothly because resistance to movement of the rack bar due to changes in internal pressure does not occur.

Image of vehicle using steering apparatus according to the present invention The top view of the drive system of the vehicle which employ | adopted the steering device which concerns on this invention is shown, (a) is a general vehicle system, (b) is a steer-by-wire system. Sectional view showing the support state of the wheel Top view of steering apparatus according to the present invention (a state in which a pair of rack bars are brought close to each other) A plan view of the steering device according to the present invention (a state where a pair of rack bars are opened) 4 is a perspective view of the steering device shown in FIG. 4 is a plan view of the steering device shown in FIG. The side view which shows the state which connected the ventilation member to the steering apparatus shown in FIG. The front view which shows the inside of the steering device shown in FIG. It is a front view which shows the principal part of the steering apparatus shown in FIG. 4, (a) is the separation state of a connection mechanism, (b) is the connection state of a connection mechanism. FIG. 5 is a perspective view of the steering device shown in FIG. FIG. 5 is a plan view of the steering device shown in FIG. FIG. 2 is a plan view showing a normal driving mode of the vehicle of FIG. FIG. 2 is a plan view showing the small turn mode of the vehicle shown in FIG. The top view which shows the spot rotation mode of the vehicle of FIG. FIG. 2 is a plan view showing a lateral running mode of the vehicle of FIG.

  An embodiment of the present invention will be described with reference to the drawings. In this embodiment, in-wheel motors M are mounted on the steering wheels 10 and 20 of the drive wheels of the vehicle 1 in the wheels of all the front and rear wheels and the right and left wheels w. By providing the in-wheel motor M, various travel patterns are possible.

  FIG. 1 shows an image diagram of a vehicle 1 (for side-by-side two-seater) using a steering device according to the present invention. The vehicle 1 is configured such that the wheel w can be steered via the steering shaft 3 by the operation of the steering 2.

  FIG. 2 is a plan view showing a drive system of the vehicle 1 of this embodiment. In this vehicle 1, steering devices 10 and 20 according to the present invention are connected to left and right front wheels (FL and FR) and left and right rear wheels (RL and RR) via tie rods 12 and 22, respectively. In-wheel motors M are mounted in the wheels of all four wheels w connected to the tie rods 12 and 22.

  The steering device 10 for the front wheels operates in accordance with a method (see FIG. 2A) adopted for a general vehicle that is steered by a steering shaft 3 that is rotated by a rotation operation of the steering 2, and a rotation operation of the steering 2. Any of the steer-by-wire systems (see FIG. 2B) for steering by an actuator 31 such as a motor can be adopted. In any case, the rotation accompanying the rotation operation is transmitted to the pinion shaft 61 (see FIG. 9) of the steering device 10, and the turning can be performed by rotating the pinion shaft 61. As shown in FIGS. 2 (a) and 2 (b), the steering device 20 for the rear wheels employs a steer-by-wire system that is steered by an actuator 31 such as a motor that operates in accordance with the rotation operation of the steering 2. It is steered in the same way as the front wheels.

  FIG. 3 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 the kingpin axis P connecting the center lines 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. It has become. The in-wheel motor M is configured by sequentially arranging a motor unit 101, a reduction gear 102, and a wheel bearing 103 in series from the inside of the vehicle body toward the wheel w.

  The steering devices 10 and 20 may be employed for both the front wheels and the rear wheels, or the steering device 20 may be employed only for the rear wheels, and an ordinary general steering device may be employed for the front wheels. .

  The steering devices 10 and 20 will be described in detail with reference to FIGS. The steering devices 10 and 20 are provided with a pair of rack bars for turning the left and right wheels w. Hereinafter, as shown in FIGS. 2 (a) and 2 (b), the rack bar connected to the left wheel w with respect to the front-rear direction of the vehicle 1 is referred to as the first rack bar 53 and the right wheel as shown in FIG. The rack bar connected to w is referred to as a second rack bar 54. The rack bars 53 and 54 can be moved by the same distance in the opposite directions from each other by a rack bar operating means 60 described later. Note that the direction indicated by the arrow pointing left in FIG. 2 is the forward direction of the vehicle 1. The same applies to FIGS. 13 to 16 described later.

  Each rack bar 53, 54 has an accordion cylinder shape in order to prevent entry of foreign matter such as rainwater, muddy water, and dust into the steering devices 10, 20 and to prevent the grease from flowing out from the steering devices 10, 20. The boots 70 are respectively provided so as to ensure hermeticity. One end side of the boot 70 is attached to a boot attachment portion provided in the rack case 50, and the other end side is attached to rack front end portions 53c and 54c of the rack bars 53 and 54, respectively.

  The rack case 50 is fixed to the frame side of the vehicle 1, and the boots 70, 70 can freely expand and contract as the rack bars 53, 54 move (see FIGS. 4 and 5). The steering device is also provided with a motor 31. During the rotation operation of the steering wheel 2 (see FIG. 2), the motor 31 can be driven simultaneously to assist the steering operation. In the case of the steer-by-wire system (see FIG. 2B), the steering is enabled by driving the motor 31 together with the rotation operation of the steering 2. 6 and 7 show a state in which the boots 70 provided on the steering devices 10 and 20 shown in FIG. 4 are removed.

  As shown in FIG. 8, the rack case 50 of the steering devices 10, 20 is formed with an outside air port 72 that communicates the air inside and outside the boot 70, and the outside air port 72 has an opening that faces the outside of the vehicle 1. A hose-like ventilation member 74 that connects between the two and 73 is connected. By setting the height b from the ground G to the opening 73 at least twice as high as the height a from the ground G to the outside air port 72, the wheel w becomes a foreign object such as rainwater or muddy water as the vehicle 1 travels. Even if it is bounced up, the foreign matter does not reach the opening 73. For this reason, it is possible to reliably prevent foreign matters such as rainwater and muddy water from entering the boot 70 (in the steering devices 10 and 20) through the outside air port 72.

  A blocking member 75 is provided near the outlet of the ventilation member 74. By providing the blocking member 75, it is possible to stop the foreign matter flowing in the flow path while allowing the air flow, and to prevent the foreign matter from being sucked into the boot 70 together with the air and causing trouble. be able to. As the blocking member 75, a net or a filter can be employed.

  If the outside air port 72 is formed in the rack case 50 that does not move to the left and right during turning, the ventilation member 74 connected to the outside air port 72 is stable without being shaken during turning. As long as this air can be communicated, it is allowed to form the outside air port 72 at a position other than the rack case 50 (for example, the boot 70).

  When the paired rack bars 53 and 54 are brought close to each other (the state shown in FIG. 4) to the opened state (the state shown in FIG. 5), the boot 70 extends and its internal volume increases. In this case, an amount of air corresponding to the increased internal volume is sucked into the boot 70 through the outside air port 72. Therefore, the internal pressure can be kept substantially constant, and the boot 70 is crushed (dented) due to a decrease in the internal pressure accompanying an increase in the internal volume. Can be prevented from being damaged.

  Further, when the pair of rack bars 53 and 54 is moved from the open state (the state shown in FIG. 5) to the close state (the state shown in FIG. 4), the boot 70 is contracted and the internal volume thereof is reduced. In this case, an amount of air corresponding to the reduced internal volume is discharged to the outside of the boot 70 through the outside air port 72. For this reason, the internal pressure can be kept substantially constant as described above, and the boot 70 can be prevented from inflating and coming into contact with peripheral members on the outside due to the decrease in the internal volume and being damaged. it can.

  In addition, as the pair of rack bars 53 and 54 move in the reverse direction, the air in the boot 70 can be freely taken in and out through the outside air port 72, so that the change in the internal pressure of the boot 70 is caused by the rack bars 53 and 54. Thus, the rack bars 53 and 54 can be moved smoothly. For this reason, extra power is not required for the movement, and the fuel efficiency of the vehicle 1 can be improved. In this embodiment, the outside air port 72 is formed in the rack case 50, but can also be formed in the boot 70 itself. Even if it does in this way, it is because the objective of the external opening 72 of communicating the air inside and outside the boot 70 can be achieved.

  A steering shaft 3 is connected to the steering devices 10 and 20 via a steering joint. When the steering 2 is rotated, the rotational force is transmitted to the pinion shaft 61 (see FIG. 9) described later by the steering shaft 3 and the steering joint, and acts as a driving force for moving the rack bars 53 and 54. Tie rods 12 and 22 are connected to the ends of the rack bars 53 and 54, and the tie rods 12 and 22 are directly connected to the wheels w.

  The internal configuration of the steering devices 10 and 20 is shown in FIGS. FIG. 9 shows a state in which the boots 70 provided on the rack bars 53 and 54 are removed.

  The pinion shaft 61 shown in FIG. 9 is connected to the steering shaft 3 (see FIG. 2A) or the actuator 31 such as a motor that operates by the rotation operation of the steering 2 (see FIG. 2B). A first pinion gear 62 is coupled to the pinion shaft 61 so as to be integrally rotatable, and a second pinion gear 65 is provided coaxially with the first pinion gear 62. The first pinion gear 62 meshes with the steering rack gear 53 b formed on the first rack bar 53, and the second pinion gear 65 meshes with the steering rack gear 54 b formed on the second rack bar 54. The steering rack gears 53b and 54b function as a driving force input means for moving the rack bars 53 and 54 along the parallel direction of the rack teeth with respect to the frame of the vehicle 1.

  Between the first pinion gear 62 and the second pinion gear 65, there is provided a coupling mechanism 63 that couples or separates both pinion gears 62, 65 in the rotational direction. FIG. 10A shows a state where the coupling mechanism 63 is separated, and FIG. 10B shows a state where the coupling mechanism 63 is coupled. The connection mechanism 63 will be described in detail later.

  The steering devices 10 and 20 include rack bar operating means 60 shown in FIG. The rack bar operating means 60 includes a first rack bar 53 and a second rack bar along the left-right direction with respect to the straight traveling direction of the vehicle 1, that is, along the direction in which the rack bars 53, 54 extend and contract (the direction in which the rack teeth are parallel). 54 has the function of moving the same distance in the opposite directions (reciprocal directions) by the same distance.

  As shown in FIG. 9, the rack bar operating means 60 is a rack gear of the pair of rack bars 53, 54 facing each other, that is, the synchronization rack gear 53 a of the first rack bar 53 and the synchronization rack gear 54 a of the second rack bar 54. A first synchronization gear 55 that meshes with the first synchronization gear 55, a second synchronization gear 56 that meshes with the first synchronization gear 55, a first pinion gear 62 that meshes with the steering rack gear 53 b formed on the first rack bar 53, and a second rack bar 54, a second pinion gear 65 that meshes with the turning rack gear 54b, a coupling mechanism 63 that contacts and separates the rotation of the two pinion gears 62 and 65, and an input shaft 66 (pinion shaft 61).

  The first synchronization gear 55 includes three gears 55a, 55b, and 55c arranged in parallel at a constant interval along the parallel direction of the rack teeth of the pair of rack bars 53 and 54. While the coupling of the first and second pinion gears 62 and 65 by the coupling mechanism 63 is in a separated state (see FIG. 10A), the first rack bar 53 is driven by the driving force input from the rack bar operating means 60. When the rack teeth are moved in one direction with respect to the parallel direction of the rack teeth, the movement is converted into the movement of the second rack bar 54 in the other direction.

  As shown in FIG. 9, gears 56 a and 56 b constituting the second synchronization gear 56 are disposed 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. The second synchronization gear 56 meshes only with the first synchronization gear 55 without meshing 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. 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 smoothly move relative to each other.

  In the straight traveling state (see FIG. 2), the first pinion gear 62 and the second pinion gear 65 are rotationally fixed by engaging the coupling mechanism 63 at the position of the wheel w (rack bars 53 and 54) in the straight traveling state (see FIG. 2). 10 (b)). In this state, when the steering 2 is rotated and the steering shaft 3 is rotated, the first rack bar 53 and the second rack bar 54 are simultaneously moved by the same distance in the same direction in the left-right direction in the rack case 50 attached to the frame. The left and right wheels w are steered in the same direction (see FIG. 13).

  For example, when switching to a special travel mode such as an in-situ rotation mode (see FIG. 15) described later, the coupling mechanism 63 is once separated (see FIG. 10A). In this state, the first rack bar 53 is moved in one direction by the input of the driving force from the rack bar operating means 60. Then, the movement direction of the first rack bar 53 is opposite to the moving direction of the first rack bar 53 via the first synchronization gear 55 meshing with both the first rack bar 53 and the second rack bar 54, that is, as shown in FIGS. Thus, the 2nd rack bar 54 moves to the direction which both the rack bars 53 and 54 open, and the right-and-left wheel w steers to a reverse direction (refer FIG. 15).

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

  The rack bar operation means 60 of the front-wheel steering device 10 includes an input shaft 66 that directly rotates in accordance with the rotation operation of the steering 2 performed by the driver, and a second pinion gear 65 that transmits torque via a gear. Thus, instead of directly rotating the input shaft 66 in accordance with the rotation operation of the steering wheel 2 performed by the driver, the driving force of the mode switching actuator 32 operating in conjunction with the rotation operation of the steering wheel 2 performed by the driver is used. Alternatively, the rotation can be transmitted to the input shaft 66 side 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 operation means 60 of the rear wheel steering device 20 is driven by the driving force of the mode switching actuator 32 that operates in conjunction with the rotational operation of the steering 2 performed by the driver or the mode switching means 42 of the vehicle 1. An input shaft 66 that transmits torque by the driving force of the mode switching actuator 32 that operates in conjunction with the operation, and a second pinion gear 65 that transmits torque from the input shaft 66 via a gear are provided.

  The rack bar operation means 60 includes a first pinion gear 62 integrated with or coupled to a first rotation shaft (pinion shaft) 61, a second rotation shaft 64 disposed coaxially with the first rotation shaft 61, A second pinion gear 65 is attached to the two rotary shaft 64 so as to be integrally rotatable. As shown in FIG. 10A, the first pinion gear 62 meshes with the steering rack gear 53 b of the first rack bar 53, and the second pinion gear 65 meshes with the steering rack gear 54 b of the second rack bar 54. ing.

  Between the first pinion gear 62 and the second pinion gear 65, a coupling mechanism 63 that can be coupled and separated from each other is provided. The coupling mechanism 63 has a state in which the first rotating shaft 61 and the second rotating shaft 64 can be relatively rotated (separated state) (see FIG. 10A) and a state in which the first rotating shaft 61 and the second rotating shaft 64 cannot be relatively rotated (coupled state) ( b) see)).

  As shown in FIG. 10, the coupling mechanism 63 includes a fixing portion 63b on the second rotating shaft 64 side and a moving portion 63a on the first rotating shaft 61 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 can rotate together. 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 in the axial direction with respect to 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 first rotating shaft 61 and the second rotating shaft 64 rotate independently. That is, the first pinion gear 62 and the second pinion gear 65 can be independently rotated.

  When the first pinion gear 62 and the second pinion gear 65 are capable of relative rotation due to the separation of the coupling mechanism 63, the first pinion gear 62 is engaged with the first rack bar 53, and the second pinion gear 65 is engaged with the second rack. It meshes with the 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. At this time, when a rotational force is 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 1. When the first rack bar 53 moves in the lateral direction, the first synchronization gear 55 rotates, and the second rack bar 54 moves simultaneously 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 is freely rotated by the movement of the second rack bar 54.

  As described above, the first rackion gear 62 and the second pinion gear 65 can be switched to the coupled state or the separated state by the coupling mechanism 63 so that the pair of rack bars 53 and 54 move integrally in the left-right direction. Thus, it is possible to easily switch between the state of moving separately in the opposite direction.

  That is, the coupling mechanism 63 is coupled so that the pair of rack bars 53 and 54 move together in the left-right direction, and the driver operates the steering wheel 2 to move the left and right wheels w to the kingpin axis P (see FIG. 3) can be simultaneously steered around in the same direction. 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, by separating the coupling mechanism 63 so that the pair of rack bars 53 and 54 are separately moved in opposite directions, the left and right wheels w are rotated in the opposite direction around the kingpin axis P (see FIG. 3). It is possible to simultaneously steer in opposite directions.

  When the traveling mode is switched, the driving force of the mode switching actuator 32 (see FIG. 2) is input to the rack bars 53 and 54 through the rotation of the pinion gears 62 and 65, respectively. Note that when the driving force of the mode switching actuator 32 is input to the rack bars 53 and 54 through the rotation of the pinion gears 62 and 65, the rotation of the steering shaft 3 may not be transmitted to the steering 2. However, the transmission may be allowed.

  Furthermore, the normal steering actuator 31 can also serve as the mode switching actuator 32. That is, the normal steering actuator 31 may transmit torque to the input shaft 66 via the steering shaft 3 when the mode is switched. Further, the role of the mode switching actuator 32 can be substituted by the driving force of the in-wheel motor M provided on each wheel w.

  Note that the configurations of the coupling mechanism 63 and the rack bar operation means 60 described above are merely examples, and the configuration of the present invention can be applied to different types of steering devices.

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

(Normal driving mode)
2 (a) and 2 (b), the first rack bar 53 and the second rack bar 54 held by the rack case 50 of the front wheel steering device 10 can be moved integrally, that is, The first pinion gear 62 and the second pinion gear 65 are connected to each other by the connecting mechanism 63 (see FIG. 10B). In this state, when the input shaft 66 is rotated by the driving force of the normal steering actuator 31 or the operation of the steering 2, the pair of rack bars 53 and 54 in the rack case 50 attached to the frame of the vehicle 1 are left and right. The left and right wheels w are steered by a predetermined angle in the same direction. FIG. 13 shows a state steered to the right. In this way, the pair of rack bars 53 and 54 can be completely integrated by the connecting mechanism 63, so that the driver can operate the steering 2 in a straight line, right turn, left turn, and the like as in the case of the normal vehicle 1. Steering can be performed.

  In the normal travel mode, when the wheels w are steered in the same direction, the rack bars 53 and 54 move in the same direction, so that the total inner volume of the left and right boots 70 is almost unchanged during the steer operation. It does not change. For this reason, the internal pressure of the boot 70 hardly changes, and the boot 70 can be smoothly steered without contacting the peripheral members.

(Turn mode)
The small turning mode (so-called 4WS vehicle) is shown in FIG. In addition to the operation of the front-wheel steering device 10 shown in FIG. 13, the first rack bar 53 and the second rack bar 54 held by the rack case 50 of the rear-wheel steering device 20 can be moved integrally, that is, a coupling mechanism. 63, the first pinion gear 62 and the second pinion gear 65 are connected to each other (see FIG. 10B). As with the front wheels, the pair of rack bars 53 and 54 in the rack case 50 attached to the frame of the vehicle 1 are moved the same distance in the same direction in the left and right directions by the driving force of the normal steering actuator 31, and the left and right wheels w Is steered at a predetermined angle in the same direction that is opposite in phase to the steering direction of the front wheels (when the front wheels are steered to the right, the rear wheels are steered to the left). By turning the front and rear wheels as shown in FIG. 14, it is possible to make a small turn with a smaller turning radius than in the normal travel mode.

  In the small turn mode, when the front and rear wheels w are steered in the same direction, the rack bars 53 and 54 of the front and rear steering devices 10 and 20 move in the same direction. The total inner volume of the boot 70 is almost unchanged. For this reason, the internal pressure of the boot 70 hardly changes, and the boot 70 can be smoothly steered without contacting the peripheral members.

(In-situ rotation mode)
The in-situ rotation mode is shown in FIG. Switching from the normal travel mode to the in-situ rotation mode is performed by the first rack bar held by the rack case 50 of the front and rear wheel steering devices 10 and 20 at the straight wheel position shown in FIGS. 53 and the second rack bar 54 are moved in the left and right reverse directions, that is, after the connecting mechanism 63 is separated (see FIG. 10A). In this state, when the input shaft 66 is rotated by the driving force of the normal steering actuator 31 or the mode switching actuator 32 or the operation of the steering 2, the pair of rack bars 53 in the rack case 50 attached to the frame of the vehicle 1. , 54 move the same distance in the left-right reverse direction, and the left and right wheels w are steered by a predetermined angle in the reverse direction.

  The first rack bar 53 and the second rack bar 54 are moved in opposite directions to each other, and as shown in FIG. 15, the connecting mechanism 63 is coupled and fixed at a position where the central axes of all four front and rear wheels w are substantially directed to the vehicle center. (See FIG. 10B). Since the central axes of all the four wheels w are substantially directed to the vehicle center, the vehicle center is in a certain state (or substantially not moved) by the driving force of the in-wheel motor M provided on each wheel w. ) Is maintained, and so-called in-situ rotation is possible.

  FIG. 15 shows a configuration in which 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 rotation is possible.

  In the in-situ rotation mode, when the front and rear wheels w are respectively steered in the reverse direction, the rack bars 53 and 54 of the front and rear steering devices move in the reverse direction. The sum of the internal volume varies greatly. By forming the outside air port 72 in the rack case 50, when the pair of rack bars 53 and 54 move in the opposite directions away from each other and the internal volume of the boot 70 increases, it corresponds to the increased internal volume. A sufficient amount of air is sucked into the boot 70 through the outside air port 72. On the other hand, when the pair of rack bars 53, 54 move in the opposite direction so as to approach each other and the internal volume of the boot 70 decreases, an amount of air corresponding to the reduced internal volume flows into the outside air port 72. It passes through the boot 70 and passes through. For this reason, the internal pressure of the boot 70 can be kept substantially constant, and the boot 70 is crushed (dented) to contact the rack bars 53 and 54 and peripheral members inside the boot 70, or the boot 70 swells to the outside periphery thereof. Contact with the member can prevent the boot 70 from being damaged.

(Horizontal running mode)
A side running mode is shown in FIG. As in the case of the in-situ rotation mode, switching from the normal running mode to the side running mode is performed at the wheel position in the straight traveling state shown in FIGS. 2 (a) and 2 (b). The first rack bar 53 and the second rack bar 54 held by 50 are moved in the left-right reverse direction, that is, after the connecting mechanism 63 is separated (see FIG. 10A). In this state, when the input shaft 66 is rotated by the driving force of the normal steering actuator 31 or the mode switching actuator 32 or the operation of the steering 2, the pair of rack bars 53 in the rack case 50 attached to the frame of the vehicle 1. , 54 move the same distance in the left-right reverse direction, and the left and right wheels w are steered 90 degrees in the reverse direction.

  The first rack bar 53 and the second rack bar 54 are moved in opposite directions to each other, and as shown in FIG. 16, the coupling mechanism 63 is coupled at a position where all the four front and rear wheels w face 90 degrees with respect to the straight direction. It fixes (refer FIG.10 (b)). When the steering 2 is operated in this state, the lateral movement angle can be finely adjusted.

  FIG. 16 shows a configuration in which 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, You can run sideways.

  In the lateral running mode, when the front and rear wheels w are steered in the opposite directions, the rack bars 53 and 54 of the front and rear steering devices 10 and 20 move in the opposite directions. The total inner volume of the boot 70 varies greatly. By forming the outside air port 72 in the rack case 50, when the pair of rack bars 53 and 54 move in the opposite directions away from each other and the internal volume of the boot 70 increases, it corresponds to the increased internal volume. A sufficient amount of air is sucked into the boot 70 through the outside air port 72. On the other hand, when the pair of rack bars 53, 54 move in the opposite direction so as to approach each other and the internal volume of the boot 70 decreases, an amount of air corresponding to the reduced internal volume flows into the outside air port 72. It passes through the boot 70 and passes through. For this reason, the internal pressure of the boot 70 can be kept substantially constant, and the boot 70 is crushed (dented) to contact the rack bars 53 and 54 and peripheral members inside the boot 70, or the boot 70 swells to the outside periphery thereof. Contact with the member can prevent the boot 70 from being damaged.

  The in-situ rotation mode and side running mode described above are merely examples, and the configuration of the present invention can be applied to a running mode in which the internal volume of the boot 70 changes.

  In the present invention, the entire rack bars 53 and 54 constituting the steering devices 10 and 20 are covered with the expansion and contraction members 70 (boots), and the outside air vents that allow the air inside and outside the expansion and contraction members 70 to communicate with the steering devices 10 and 20. 72, and when the internal volume of the expansion / contraction member 70 changes when the travel mode is switched between the normal travel mode and the special travel mode such as the in-situ rotation mode and the lateral travel mode, the internal volume changes. A corresponding amount of air was taken in and out of the open air vent. Thereby, as the internal volume of the elastic member 70 changes, the elastic member 70 is crushed (dented) to contact the rack bars 53 and 54 and peripheral members inside thereof, or the elastic member 70 swells to the outside. It is possible to improve the durability by preventing the elastic member 70 from being damaged by contacting with the peripheral members of the rack bar, and to reduce the movement resistance of the rack bars 53 and 54 due to the change in internal pressure. Can be done smoothly.

12, 22 Tie rods 53, 54 Rack bar 55 Synchronous gear 60 Rack bar operating means 70 Extendable member (boot)
72 Outside air opening 73 Opening 74 Ventilation member 75 Blocking member w Wheel G Ground

Claims (3)

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);
A pair of rack bars (53, 54) respectively connected to the tie rods (12, 22) of the left and right wheels (w);
The pair of rack bars (53, 54) mesh with each other, and the movement of one rack bar (53) in one direction with respect to the parallel direction of the rack teeth is changed to the movement of the other rack bar (54) in the other direction. A synchronous gear (55) to convert,
Rack bar operating means (60) capable of moving the pair of rack bars (53, 54) in opposite directions along the parallel direction of the rack teeth of the respective rack bars (53, 54);
An elastic member (70) that covers the entire pair of rack bars (53, 54) and expands and contracts as the rack bars (53, 54) move;
An outside air port (72) communicating the inside and outside air of the elastic member (70);
A steering apparatus having   An opening (73) facing the outside of the vehicle; and a ventilation member (74) for connecting the opening (73) and the outside air port (72) to allow air to pass therethrough, and the ground (G) The steering device according to claim 1, wherein a height from a ground to the opening (73) is at least twice as high as a height from the ground (G) to the outside air port (72).   The steering apparatus according to claim 1 or 2, wherein a blocking member (75) for stopping foreign matter flowing in the flow path while allowing air flow is provided in a flow path of air passing through the outside air port (72). .

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