JP4797502B2 - Vehicle steering control device - Google Patents

Description

  The present invention relates to a steering control device that is mounted on a vehicle such as an automobile and controls steering of the vehicle.

As a conventional vehicle steering control device, for example, as described in Patent Document 1, a steering shaft connected to a steering handle, a rack shaft connected to wheels, and a steering shaft and a rack shaft are connected. There is known a gear device that transmits a steering amount of a steering wheel to a wheel via a steering shaft, a gear device, and a rack shaft to steer the wheel.
JP 2003-261038 A

  However, the following problems exist in the prior art. In other words, if the wheels are equipped with sidewall-reinforced run-flat tires, run on an uneven road surface such as a rutted road with the air pressure of the run-flat tires being sufficiently low (puncture state). The contact pressure applied to the tread shoulder portion of the run flat tire increases. For this reason, the torque which steers a wheel generate | occur | produces in a run flat tire, and there exists a possibility that the torque may be transmitted to a steering system. In particular, during running on rutting roads, the ground pressure on the inside of the tread shoulder of the runflat tire increases or the ground pressure on the outside of the tread shoulder increases. It becomes easy. When the torque generated at the wheels is transmitted to the steering system in this way, the driver may feel uncomfortable.

  An object of the present invention is to provide a vehicle steering control device capable of suppressing the torque generated in a run-flat tire from being transmitted to a steering system when the run-flat tire has a low air pressure. .

The present invention relates to a steering control device for a vehicle having wheels equipped with sidewall-reinforced run-flat tires, wheel steering means for turning the wheels according to the steering amount provided in the vehicle, and a run flat. The air pressure detecting means for detecting whether or not the tire air pressure is lower than a predetermined value, and when the air pressure detecting means detects that the air pressure of the run flat tire is lower than the predetermined value, the run flat tire is mounted. The steering wheel force control means for controlling the axial force transmission efficiency of the wheel turning means for the wheel that has been lowered to be lower than that in the normal state, and the air pressure of the run flat tire has become lower than the predetermined value by the air pressure detection means. Is detected, the turning amount of the wheel on the opposite side to the wheel on which the run-flat tire is mounted becomes larger than that in the normal state. It is characterized in further comprising a means for controlling the urchin wheel turning means. The normal state here means a state where the air pressure of the run flat tire is not lower than a predetermined value.

In such a vehicle steering control device, in a normal state, the axial force transmission efficiency of the wheel steering means with respect to the wheels is so high that the wheel steering means turns the wheels according to the steering amount of the steering. . On the other hand, for example, when the run-flat tire is punctured and the air pressure of the run-flat tire becomes lower than a predetermined value, the axial force transmission of the wheel turning means to the wheel on which the run-flat tire is mounted is performed by the turning axial force control means. Efficiency becomes lower (including 0%) than during normal driving. For this reason, even if the run-flat tire has a sufficiently low air pressure, for example, when running on a non-uniform road surface such as a rutted road, even if torque that turns the wheels is generated in the run-flat tire, the torque is It becomes difficult to be transmitted to the steering system.
Also, if the axial force transmission efficiency of the wheel steering means for a wheel fitted with a run-flat tire with reduced air pressure is sufficiently lowered, the vehicle is only turned with normal wheels on the opposite side to the left and right of the wheel. I do not get. Therefore, when the air pressure of the run flat tire becomes lower than the predetermined value, the vehicle is controlled so that the turning amount of the normal wheel on the opposite side to the wheel fitted with the run flat tire is larger than that in the normal state. By controlling the wheel turning means, the cornering force necessary for turning can be obtained with only the normal wheels. Thereby, the fall of the turning property of a vehicle can be prevented.

  Preferably, the wheel turning means has a drive portion provided between a first connecting member connected to the steering and a second connecting member connected to the wheel, and the operation of the first connecting member is second. It is a means to transmit to a connection member.

  In this case, the wheel steering means can be realized with a simple configuration including an actuator such as an electric motor.

Preferably, the vehicle further comprises reverse detection means for detecting whether or not the vehicle is in the reverse state, and the steered axial force control means is configured such that when the vehicle is not in the reverse state, the air pressure of the run flat tire is detected by the air pressure detection means. When it is detected that the value is lower than the predetermined value, control is performed so that the axial force transmission efficiency of the wheel turning means with respect to the wheel on which the run-flat tire is mounted is lowered than in the normal state .

  In general vehicles, the kingpin shaft of the wheel is ahead of the center of the ground contact surface of the tire. Therefore, if the axial force transmission efficiency of the wheel steering means with respect to the wheel is lower than that during normal driving, the tire The slip angle of the tire increases to 0 degrees, but when the vehicle moves backward, the slip angle of the tire increases. Therefore, it is detected whether or not the vehicle is in the reverse state by the reverse detection means, and only when the vehicle is not in the reverse state, the axial force transmission efficiency of the wheel steering means for the wheel equipped with the run-flat tire with low air pressure is determined. Make it lower than during normal driving. In other words, when the vehicle is in the reverse state, the axial force transmission efficiency of the wheel steering means for the wheel fitted with the run-flat tire with low air pressure is prevented from being lowered than during normal running. Accordingly, it is possible to reliably prevent the run-flat tire from being steered unnecessarily because the slip angle of the run-flat tire becomes too large when the vehicle moves backward.

  Further preferably, the vehicle further includes steering detection means for detecting a steering amount of the steering, and the turning axial force control means detects that the air pressure of the run-flat tire has become lower than a predetermined value by the air pressure detection means. The axial force transmission efficiency of the wheel steering means for the wheel fitted with the run-flat tire is controlled according to the steering amount.

  If the axial force transmission efficiency of the wheel steering means for a wheel equipped with a run-flat tire with reduced air pressure is too low, the turning sideways generated on the wheel when the driver turns the vehicle by performing a steering operation. The power is reduced. Therefore, the steering detection means detects the steering amount of the steering, and increases the axial force transmission efficiency of the wheel turning means for the wheel fitted with the run-flat tire with reduced air pressure, for example, as the steering amount of the steering increases. To do. As a result, when the steering amount is large, the turning lateral force generated on the wheel equipped with the run-flat tire with low air pressure increases, so that the vehicle can turn with a small radius.

  ADVANTAGE OF THE INVENTION According to this invention, it can suppress that the torque which generate | occur | produced with the run flat tire is transmitted to a steering system, when driving | running | working on uneven road surfaces, such as a rutted road, in the state where the air pressure of the run flat tire became low. . As a result, it is possible to reduce the uncomfortable feeling felt by the driver by transmitting the torque fluctuation generated in the run-flat tire to the steering system.

  DESCRIPTION OF EMBODIMENTS Hereinafter, a preferred embodiment of a vehicle steering control device according to the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a schematic view showing a vehicle provided with a first embodiment of a steering control device according to the present invention. In the figure, a vehicle 1 includes four wheels 2 (only a steering wheel is shown here), a steering wheel (hereinafter simply referred to as steering) 3 for a driver to perform a steering operation, and a steering control device 4. ing. Each wheel 2 is equipped with a sidewall-reinforced run-flat tire 5 that can travel even when punctured.

  The steering control device 4 operates the tie rod 7 connected to the left and right wheels 2 via the knuckle arms 6, the steering gear box 9 connected to the steering 3 via the steering shaft 8, and the operation of the steering gear box 9. A steering transmission unit 10 is provided for transmitting to the left and right tie rods 7 respectively.

  The specific structures of the tie rod 7, the steering gear box 9, and the steering transmission unit 10 are shown in FIG. In the figure, the tie rod 7 is provided with a rack 11. The steering gear box 9 includes a rack shaft portion 13 having a rack 12 and a pinion gear 14 provided at the tip of the steering shaft 8 and meshing with the rack 12.

  The steering transmission unit 10 has an electric motor (only one is shown in FIG. 2) 15 attached to both ends of the rack shaft 13, and the output shaft of the electric motor 15 meshes with the rack 11 of the tie rod 7. A pinion gear (not shown) is provided. The electric motor 15 and the pinion gear constitute a drive part provided between the tie rod 7 and the rack shaft part 13. The electric motor 15 is provided with a motor reaction force sensor 16 (for example, a strain cage) that detects torque (reaction force) applied to the output shaft.

  As shown in FIG. 1, the steering control device 4 further includes an air pressure sensor 17, a reverse switch 18, an ECU (Electronic Control Unit) 19, and a warning lamp 20. The air pressure sensor 17 is a sensor that detects the air pressure of the run-flat tire 5, and is provided on each wheel 2. The reverse switch 18 is a sensor that detects whether a reverse gear is engaged, that is, whether the vehicle 1 is in a reverse state.

  1 and 2, the ECU 19 inputs detection signals from the air pressure sensor 17, the reverse switch 18 and the motor reaction force sensor 16, performs predetermined processing, controls the electric motor 15, and the run-flat tire 5 is punctured. When the warning lamp 20 is turned on, the warning lamp 20 is turned on. Details of the control processing procedure by the ECU 19 are shown in FIG.

  Here, in the normal state (when the run-flat tire 5 is not punctured), the electric motor 15 is controlled by the ECU 19 so as not to rotate. At this time, the output shaft of the electric motor 15 is locked to the tie rod 7, and the axial force transmission efficiency of the tie rod 7 with respect to the wheel 2 (hereinafter referred to as tie rod axial force transmission efficiency) is 100%. In this state, when the rack shaft portion 13 moves in either the left or right direction by the steering operation of the steering 3, the tie rod 7 moves by the same distance in the same direction, and the wheels 2 are steered according to this movement amount.

  In FIG. 3, first, the detection value of the air pressure sensor 17 provided on each wheel 2 is read (procedure 101), and it is determined whether or not the air pressure of the steering wheel 2 is lower than a predetermined value (puncture state) ( Procedure 102). When the steering wheel 2 is in a punctured state, control is performed to turn on the warning lamp 20 (procedure 103).

  Subsequently, it is determined from the detection signal of the reverse switch 18 whether or not the vehicle 1 is in the reverse state (procedure 104). The electric motor 15 is controlled so that the tie rod axial force transmission efficiency with respect to the puncture wheel becomes 0% (procedure 105). Specifically, the detection value of the motor reaction force sensor 16 is fed back, the rotation direction and the rotation speed of the electric motor 15 are determined such that the torque applied to the output shaft of the electric motor 15 becomes zero, and the electric motor is driven accordingly. The motor 15 is controlled. As a result, the output shaft of the electric motor 15 becomes free with respect to the tie rod 7, and the tie rod axial force transmission efficiency with respect to the puncture wheel becomes 0%.

  On the other hand, when it is determined in step 104 that the vehicle 1 is in the reverse state, the electric motor 15 is controlled so that the tie rod axial force transmission efficiency with respect to the puncture wheel becomes 100% as in the normal state (step 106). .

  In the steering control device 4 as described above, the knuckle arm 6, the tie rod 7, the steering shaft 8, the steering gear box 9, and the steering transmission unit 10 rotate the wheel 2 according to the steering amount of the steering 3 provided in the vehicle 1. Wheel steering means for steering is configured. Steps 101 and 102 of the air pressure sensor 17 and the ECU 19 constitute air pressure detecting means for detecting whether or not the air pressure of the run flat tire 5 has become lower than a predetermined value. When the air pressure detecting means detects that the air pressure of the run flat tire 5 is lower than a predetermined value, the steps 104 to 106 of the motor reaction force sensor 16 and the ECU 19 apply to the wheel 2 to which the run flat tire 5 is attached. A turning axial force control means is configured to control the axial force transmission efficiency of the wheel turning means to be lower than that in the normal state.

  By the way, the run-flat tire 5 supports the weight of the vehicle body at the time of low air pressure (at the time of puncture) by the sidewall, so that the rigidity of the sidewall is high. For this reason, as the contact pressure distribution when the run flat tire 5 is punctured, the pressure on both sides of the tread shoulder portion is higher than that in the normal state. Therefore, when the run-flat tire 5 is punctured and travels on an uneven road surface such as a rutted road, a torque for turning the wheel 2 is generated around the Z-axis of the run-flat tire 5 as shown in FIG. In particular, depending on the road surface condition, the contact pressure at the inner portion of the run flat tire 5 may increase (see FIG. 4A), or the contact pressure at the outer portion of the run flat tire 5 may increase (see FIG. 4B). Then, torque fluctuations that occur around the Z axis of the run flat tire 5 are likely to occur.

  At this time, when the tie rod axial force transmission efficiency with respect to the puncture wheel is 100%, when torque vibration occurs in the run-flat tire 5, the torque vibration is converted into the knuckle arm 6, tie rod 7, This is transmitted to the steering 3 via the steering transmission unit 10, the steering gear box 9, and the steering shaft 8, and the steering 3 vibrates. For this reason, the driver who operates the steering wheel 3 feels uncomfortable.

  On the other hand, in the present embodiment, when the air pressure of the run flat tire 5 decreases more than necessary, the tie rod axial force transmission efficiency for the wheel 2 equipped with the low air pressure run flat tire 5 becomes 0% when the vehicle 1 moves forward. To be controlled. For this reason, even if the run-flat tire 5 is punctured and travels forward on a rough road surface such as a rutted road, even if torque vibration occurs in the run-flat tire 5, the torque vibration is blocked by the tie rod 7. And is not transmitted to the steering 3. As a result, it is possible to suppress the uncomfortable feeling of the steering operation received by the driver.

  Here, as shown in FIG. 6, the kingpin shaft 21 of the wheel 2 is in front of the center of the ground contact surface of the run-flat tire 5. Therefore, when the vehicle 1 travels forward, even if the tie rod axial force transmission efficiency with respect to the wheel 2 on which the low-pneumatic run-flat tire 5 is mounted is 0%, the run-flat tire 5 has a slip angle θ of 0 degree. As described above, the rotating operation is performed around the point G where the extended line of the kingpin shaft 21 and the road surface R intersect. Therefore, when the vehicle 1 travels on a non-flat road surface such as a rutted road, the movement that causes the slip angle θ of the run-flat tire 5 to approach 0 degrees is not hindered. The cornering force necessary for turning the vehicle 1 is supplemented by the wheel 2 on the opposite side to the wheel 2 on which the low-flat run-flat tire 5 is mounted.

  Since the kingpin shaft 21 of the wheel 2 is ahead of the center of the ground contact surface of the run flat tire 5 as described above, the tie rod for the wheel 2 on which the low air pressure run flat tire 5 is mounted when the vehicle 1 is retracted. If the axial force transmission efficiency is set to 0%, the slip angle θ of the run flat tire 5 increases conversely, and the run flat tire 5 may be steered carelessly. Therefore, in this embodiment, even if the air pressure of the run-flat tire 5 decreases more than necessary, when the vehicle 1 moves backward, the tie rod axial force transmission efficiency with respect to the wheel 2 equipped with the low-pressure run-flat tire 5 is 100%. It is controlled to become. Thereby, careless turning of the low-pneumatic run-flat tire 5 when the vehicle 1 moves backward can be prevented.

  In the present embodiment, when the run-flat tire 5 is punctured while the vehicle 1 is moving forward, the tie rod axial force transmission efficiency with respect to the punctured wheel is controlled to be 0%. The tie rod axial force transmission efficiency with respect to the above may be controlled to be lower than in the normal state (100%).

  FIG. 7 is a schematic view showing a vehicle provided with the second embodiment of the steering control device according to the present invention. In the figure, the same or equivalent members as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  In the figure, the steering control device 30 of the present embodiment further includes a steering angle sensor 31 in addition to the components of the steering control device 4 of the first embodiment. The steering angle sensor 31 detects the steering angle (steering amount) of the steering 3. Note that the steering amount of the steering 3 may be detected using a G sensor that detects the lateral G applied to the vehicle 1 instead of the steering angle sensor 31.

  The steering control device 30 includes an ECU 32 instead of the ECU 19 in the first embodiment. The ECU 32 inputs detection signals from the air pressure sensor 17, the reverse switch 18, the steering angle sensor 31, and the motor reaction force sensor 16 (see FIG. 2), performs predetermined processing, and controls the electric motor 15 (see FIG. 2). At the same time, the warning lamp 20 is turned on when the run-flat tire 5 is punctured. Details of the control processing procedure by the ECU 32 are shown in FIG.

  In FIG. 8, procedures 101 to 104 and 106 are the same as those of the ECU 19 in the first embodiment (see FIG. 3). When it is determined in step 104 that the vehicle 1 is not in the reverse state, first, the detection value of the steering angle sensor 31 is read (step 107). Then, the tie rod axial force transmission efficiency for the wheel (punk wheel) on which the punctured run flat tire 5 is mounted is set (procedure 108). The tie rod axial force transmission efficiency for the puncture wheel is set as follows.

  That is, tie rod axial force setting data as shown in FIG. 9 is stored in advance in a memory (not shown) of the ECU 32. This tie rod axial force setting data shows the relationship between the steering angle of the steering 3 and the tie rod axial force transmission efficiency, and is set so that the tie rod axial force transmission efficiency increases as the steering angle of the steering 3 increases. ing. In the tie rod axial force setting data, when the steering angle of the steering 3 is smaller than a predetermined angle, the tie rod axial force transmission efficiency is 0%. Using such tie rod axial force setting data, the tie rod axial force transmission efficiency for the puncture wheel is set.

  Subsequently, the electric motor 15 is controlled so that the tie rod axial force transmission efficiency with respect to the puncture wheel becomes a set value obtained from the tie rod axial force setting data (procedure 109). Specifically, for example, data (not shown) indicating the relationship between the tie rod axial force transmission efficiency and the torque applied to the output shaft of the electric motor 15 is stored in a memory in advance, and the motor is the same as in the first embodiment. The detection value of the reaction force sensor 16 is fed back, and the rotation direction and rotation speed of the electric motor 15 are obtained so that the torque applied to the output shaft of the electric motor 15 becomes the set value obtained from the tie rod axial force setting data. The electric motor 15 is controlled accordingly. Thereby, the tie rod axial force transmission efficiency with respect to the puncture wheel is in accordance with the detected value of the steering angle sensor 31 (the steering angle of the steering wheel 3).

  In the steering control device 30 as described above, when the motor reaction force sensor 16 and the steps 104 and 106 to 109 of the ECU 32 detect that the air pressure of the run-flat tire 5 has become lower than a predetermined value by the air pressure detecting means. The turning axial force control means for controlling the axial force transmission efficiency of the wheel turning means for the wheel 2 equipped with the run flat tire 5 to be lower than that in the normal state is configured.

  Thus, in the present embodiment, even if the air pressure of the run-flat tire 5 decreases more than necessary, when the steering amount of the steering 3 is larger than a predetermined angle, it is determined that the driver has performed the steering operation, and the steering is performed. 3, the tie rod axial force transmission efficiency for the wheel 2 on which the low-pneumatic run-flat tire 5 is mounted is increased. For this reason, when the vehicle 1 turns, the turning lateral force generated on the wheel 2 increases according to the steering amount of the steering 3, so that the vehicle 1 turns with a small radius even when the run-flat tire 5 is punctured. be able to. Thereby, the turning property of the vehicle 1 is improved.

  At this time, if the run flat tire 5 is punctured and travels on a rough road surface such as a rutted road, torque vibration generated in the run flat tire 5 is transmitted to the steering wheel 3 to some extent. However, when the driver is actively performing the steering operation, the driver is willing to turn, so even if the steering wheel 3 vibrates somewhat, the driver rarely feels uncomfortable with the driving. .

  Further, when the steering amount of the steering wheel 3 is large, the transmission efficiency of the tie rod axial force with respect to the punctured wheel is increased. For example, even if the wheel 2 enters immediately when the vehicle 1 turns, the two left and right wheels 2 The reverse C-shape is prevented and the vehicle 1 turns stably.

  FIG. 10 is a schematic view showing a vehicle provided with a third embodiment of the steering control device according to the present invention. In the figure, the same or equivalent members as those in the first and second embodiments are denoted by the same reference numerals, and the description thereof is omitted.

  In the figure, a steering control device 40 according to this embodiment includes an ECU 41 instead of the ECU 32 in the second embodiment. Other configurations of the steering control device 40 are the same as those in the second embodiment. The ECU 41 is different from the ECU 32 only in the control processing method. The details of the control processing procedure by the ECU 41 are shown in FIG.

  In FIG. 11, procedures 101 to 106 are the same as those of the ECU 19 in the first embodiment (see FIG. 3). After the electric motor 15 is controlled so that the tie rod axial force transmission efficiency with respect to the puncture wheel becomes 0% in the procedure 105, the detection value of the steering angle sensor 31 is read (procedure 111). Then, the steering amount of the wheel 2 on the opposite side to the puncture wheel (hereinafter referred to as normal wheel) is set as follows (procedure 112).

  That is, turning amount setting data as shown in FIG. 12 is stored in advance in a memory (not shown) of the ECU 41. This steered amount setting data indicates the relationship between the steering angle of the steering wheel 3 and the steered amount of the wheel 2 (tire cut angle). The steered amount of the wheel 2 is proportional to the steering angle of the steering wheel 3. Is set to be large. Here, the steered amount of normal wheels (P in the figure) is the steered amount of wheels 2 in the normal state (the run-flat tires 5 of the left and right steered wheels 2 are not punctured) (in the figure). Q) is set to be twice. The turning amount of the puncture wheel (R in the figure) is 0 regardless of the steering angle of the steering 3. Using such turning amount setting data, the turning amount of normal wheels is set.

  Subsequently, the electric motor 15 is controlled so that the turning amount of the normal wheel becomes the set value obtained from the turning amount setting data (procedure 113). Here, the tie rod axial force transmission efficiency for the wheel 2 in the normal state is 100%, and the tie rod axial force transmission efficiency for the punctured wheel is 0%. On the other hand, since the turning amount of the normal wheel is twice the turning amount of the wheel 2 in the normal state (see FIG. 12), the tie rod axial force transmission efficiency for the normal wheel is 200%. In this case, when the rack shaft 13 (see FIG. 2) moves in either the left or right direction by the steering operation of the steering 3, the tie rod 7 moves by a double distance in the same direction. The wheel 2 turns twice. At this time, the control of the electric motor 15 is performed by feeding back the detection value of the motor reaction force sensor 16 as in the first and second embodiments.

  In the steering control device 40 as described above, the steering angle sensor 31, the motor reaction force sensor 16, and the steps 111 to 113 of the ECU 41 detect that the air pressure of the run-flat tire 5 has become lower than a predetermined value by the air pressure detecting means. Then, a means for controlling the wheel turning means is configured so that the turning amount of the wheel 2 on the opposite side to the wheel 2 on which the run-flat tire 5 is mounted is larger than that in the normal state.

  As described above, in this embodiment, when the air pressure of the run flat tire 5 decreases more than necessary, the tie rod axial force on the wheel 2 (normal wheel) opposite to the wheel 2 on which the low air pressure run flat tire 5 is mounted. By making the transmission efficiency larger than 100%, the steering amount of the normal wheel is increased from the normal state. Thereby, it is possible to obtain a cornering force necessary for turning with only one normal wheel. Accordingly, a decrease in cornering force due to puncture of the run-flat tire 5 can be suppressed, and the turning performance of the vehicle 1 is improved.

  Although several preferred embodiments of the vehicle steering control apparatus according to the present invention have been described above, the present invention is not limited to the above-described embodiments.

  For example, in the steering control device of the above embodiment, as shown in FIG. 2, the steering transmission unit 10 having the electric motor 15 is provided, and the operation of the steering gear box 9 is transmitted to the tie rod 7 by the steering transmission unit 10. The structure for transmitting the operation of the steering gear box to the tie rod is not particularly limited to this. For example, the structure shown in FIG. 13 may be used.

  In FIG. 13, the steering control device 50 has a cylinder-type tie rod 51, and a knuckle arm 6 is connected to one end of the tie rod 51. Further, both end portions of the rack shaft portion 13 of the steering gear box 9 constitute a piston rod 52 (only one side is shown in FIG. 13). The piston rod 52 is inserted into the tie rod (cylinder) 51 from the other end side of the tie rod 51. A piston 53 is coupled to the end surface of the piston rod 52. A space between the inner end surface on the knuckle arm 6 side and the piston 53 in the tie rod 51 forms a hydraulic chamber 54. The hydraulic chamber 54 is connected to an oil tank 57 and a hydraulic pump 58 via pipes 55 and 56. The hydraulic pump 58 supplies oil in the oil tank 57 to the hydraulic chamber 54. The pipes 55 and 56 are provided with electromagnetic on-off valves 59 and 60, respectively. The on-off valves 59 and 60 are controlled by an electric signal from the ECU 61.

  Here, in a normal state, the oil pressure chamber 54 in the tie rod 51 is filled with oil at a predetermined pressure, and when the rack shaft portion 13 moves, the tie rod 51 moves by the same distance in the same direction. . That is, the tie rod axial force transmission efficiency for the wheel 2 is 100%. On the other hand, when it is detected that the run-flat tire 5 is punctured, the ECU 61 controls the open / close valve 59 to switch from the closed state to the open state. Then, the oil in the hydraulic chamber 54 flows through the pipe 55 to the oil tank 57, and the hydraulic chamber 54 is almost free of oil. In this state, when the vehicle 1 travels on a rutted road or the like, torque that causes the wheel 2 to steer the wheels 2 is generated and the piston rod 52 (rack shaft portion 13) moves even if the tie rod 51 moves. There is nothing. That is, since the tie rod axial force transmission efficiency for the punctured wheel is 0%, the torque generated in the run-flat tire 5 is not transmitted to the steering 3.

  In addition to the above, the structure for transmitting the operation of the steering gear box to the tie rod may include, for example, an electromagnetic solenoid.

  In the steering control device of the above embodiment, the steering shaft 8 is mechanically connected to the tie rod 7 via the steering gear box 9, but the steering control device is mechanically connected to the tie rod. There is also a so-called steer-by-wire type in which an actuator for turning each wheel is provided independently, and the actuator is electrically driven and controlled according to the steering amount of the steering. Some of the steering control devices of this type have a function of feeding back the steered state of the wheel to the steering wheel in order to obtain a steering feeling without a sense of incongruity. The present invention can be applied.

1 is a schematic diagram showing a vehicle including a first embodiment of a steering control device according to the present invention. It is a figure which shows the structure which transmits the steering operation of the steering shown in FIG. 1 to a wheel. It is a flowchart which shows the detail of the control processing procedure by ECU shown in FIG. It is a figure which shows a mode that a torque generate | occur | produces in the punctured run flat tire. It is a figure which shows a mode that the vibration of the torque which generate | occur | produced in the punctured run flat tire is transmitted to a steering. It is a conceptual diagram which shows the relationship between the kingpin axis | shaft of a wheel and a slip angle. It is the schematic which shows the vehicle provided with 2nd Embodiment of the steering control apparatus concerning this invention. It is a flowchart which shows the detail of the control processing procedure by ECU shown in FIG. It is a graph which shows the tie rod axial force setting data used by the process shown in FIG. It is the schematic which shows the vehicle provided with 3rd Embodiment of the steering control apparatus concerning this invention. It is a flowchart which shows the detail of the control processing procedure by ECU shown in FIG. It is a graph which shows the steering amount setting data used by the process shown in FIG. It is a figure which shows the other structure which transmits the steering operation of the steering shown in FIG. 1 to a wheel.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Vehicle, 2 ... Wheel, 3 ... Steering wheel (steering), 4 ... Steering control apparatus, 5 ... Run flat tire, 6 ... Knuckle arm (2nd connection member, wheel steering means), 7 ... Tie rod (2nd Connecting member, wheel steering means), 8 ... steering shaft (first connecting member, wheel steering means), 9 ... steering gear box (first connecting member, wheel steering means), 10 ... steering transmission part (wheel turning) (Steering means), 15 ... electric motor (drive unit), 16 ... motor reaction force sensor (steering axial force control means), 17 ... air pressure sensor (air pressure detecting means), 18 ... reverse switch (reverse detecting means), 19 ... ECU (pneumatic pressure detection means, steered axial force control means), 30 ... steering control device, 31 ... steering angle sensor (steering detection means), 32 ... ECU (air pressure detection means, steered axial force control means), 40 ... steering Control device 41 ... ECU (pneumatic pressure detecting means, steered axial force control means), 50 ... steering control device, 51 ... tie rod (drive unit, wheel steered means), 52 ... piston rod (drive unit, wheel steered means) ), 55, 56 ... Pipe (steering axial force control means), 57 ... Oil tank (steering axial force control means), 58 ... Hydraulic pump (steering axial force control means), 59,60 ... Open / close valve (rolling) Rudder axial force control means), 61... ECU (air pressure detecting means, steered axial force control means).

Claims (4)

In a steering control device for a vehicle having wheels equipped with sidewall-reinforced run-flat tires,
Wheel turning means for turning the wheels according to the steering amount of the steering provided in the vehicle;
Air pressure detecting means for detecting whether the air pressure of the run-flat tire is lower than a predetermined value;
When it is detected by the air pressure detecting means that the air pressure of the run flat tire is lower than a predetermined value, the axial force transmission efficiency of the wheel turning means for the wheel on which the run flat tire is mounted is higher than that in the normal state. and turning axial force controlling means also controls to reduce,
When it is detected by the air pressure detection means that the air pressure of the run flat tire is lower than a predetermined value, the turning amount of the wheel on the opposite side to the wheel on which the run flat tire is mounted is larger than that in the normal state. And a means for controlling the wheel steering means so as to be larger .   The wheel steering means includes a drive unit provided between a first connecting member connected to the steering and a second connecting member connected to the wheel, and the operation of the first connecting member The vehicle steering control device according to claim 1, wherein the steering control device is a means for transmitting to the second connecting member. The vehicle further comprises reverse detection means for detecting whether the vehicle is in a reverse state,
The steered axial force control means detects the run flat tire when the air pressure detecting means detects that the air pressure of the run flat tire is lower than a predetermined value when the vehicle is not in a reverse state. 3. The vehicle steering control device according to claim 1, wherein control is performed so that the axial force transmission efficiency of the wheel steering means for the mounted wheel is lower than in a normal state . A steering detection means for detecting a steering amount of the steering;
When the air pressure detecting means detects that the air pressure of the run flat tire is lower than a predetermined value, the turning axial force control means The vehicle steering control device according to any one of claims 1 to 3, wherein axial force transmission efficiency is controlled in accordance with a steering amount of the steering .

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