JP3809845B2 - Vehicle ground load control device - Google Patents

Description

  The present invention relates to a vehicle ground load control device that is employed in a vehicle such as a four-wheeled vehicle.

This type of ground load control device is disclosed in Patent Document 1 below, for example. In the contact load control device shown in the following Patent Document 1, by using the active cylinder provided corresponding to each wheel, the reaction force when raising and lowering the sprung mass acts on the contact surface, The grounding load is controlled.
Japanese Patent Laid-Open No. 11-91329

  In the above-described ground load control device disclosed in Patent Document 1, the ground load of each wheel is changed by individually controlling each active cylinder provided corresponding to each wheel. . For this reason, when changing the grounding load of each wheel, there is a possibility that not only there is a change in the posture of the vehicle body, but there is also a possibility that vibration in the vertical direction occurs.

  In order to deal with the above-described problems, in the present invention, the front and rear, left and right load sharing means that respectively share the ground loads of the front and rear wheels, and the load that can change the ground load that each of these load sharing means can be changed by operation. In a vehicle ground load control device comprising a changing means, a vehicle state detecting means for detecting a vehicle state, and a control means for controlling the operation of the load changing means in response to a detection signal from the vehicle state detecting means, As the load changing means, each grounding load of one of the diagonal wheels and each grounding load of the other diagonal wheel are changed in opposite increasing and decreasing directions, and in each diagonal wheel The load changing means that can operate to change the ground contact load in the same increase / decrease direction is adopted, and the front / rear / left / right load sharing means for sharing the ground load of the front / rear / right / left wheels are respectively applied to the front / rear / right / left wheels. versus The front and rear, left and right suspension hydraulic cylinders each having a single port are mounted, and load changing means that can change the ground load shared by each suspension hydraulic cylinder by operation correspond to the left and right front wheels. One hydraulic load control hydraulic cylinder that receives the hydraulic pressure from each of the suspension hydraulic cylinders mounted and operates by differential pressure, and the hydraulic pressure from each of the suspension hydraulic cylinders mounted corresponding to the left and right rear wheels. The ratio of the axial force acting on each piston rod of the other contact load control hydraulic cylinder that operates by differential pressure and the contact load control hydraulic cylinder is changed to the fulcrum position of the arm connected to both piston rods. The axial force ratio variable mechanism that can be changed by changing the fulcrum position of the arm according to the detection signal from the vehicle state detection means It is characterized in that an actuator.

  According to the present invention, the operation of the load changing means can be controlled by the control means according to the vehicle state. For example, when turning, the ground load of one set of diagonal wheels is increased and changed while the other is changed. It is possible to decrease and change each ground load of a pair of diagonal wheels and to change each ground load in each diagonal wheel in the same increase / decrease direction. For this reason, for example, when turning left, both the ground loads on the right front wheel and the left rear wheel are reduced, and the ground loads on the left front wheel and the right rear wheel are both increased, so that the load movement is burdened on the rear side. (In other words, the rear roll stiffness distribution can be increased), and the steering characteristics can be oversteered while suppressing changes in the posture of the vehicle, or at this time, the left front wheel and the right rear wheel Reduce the ground contact load together and increase the ground load load on the right front wheel and left rear wheel together to bear the load movement on the front side (in other words, increase the front roll stiffness distribution). ), And it is possible to make the steering characteristic have an understeer tendency while suppressing the posture change of the vehicle body.

  Further, according to the present invention, it is possible to change the ratio of the axial force acting on each piston rod of the hydraulic cylinder for both contact load control by changing the fulcrum position of the arm by the actuator. For this reason, it is possible to accurately change the front-rear wheel sharing ratio of roll rigidity and roll damping. Also, because it is displacement control, not force control, when maintaining the roll rigidity front / rear wheel sharing ratio, which is easy to control, it is only necessary to maintain and hold the actuator, so each grounding load does not consume energy. Since the control hydraulic cylinder can be freely displaced even during control, it is possible to expect effects such as a small amount of road surface vibration input to the vehicle body and good ride comfort.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 schematically shows a first embodiment of a vehicle suspension device including a vehicle ground load control device according to the present invention. In this suspension device, as shown in FIGS. The hydraulic cylinders 11, 12, 13, 14 are connected to the bouncing suppressor 20, the rolling suppressor 30, the pitching suppressor 40, and the ground load changing device 50 through the pipes P1, P2, P3, P4, respectively.

  Each of the suspension hydraulic cylinders 11, 12, 13, and 14 is attached to each of the front and rear, left and right wheels (see FL, FR, RL, and RR in FIG. 14), and has a single port 11a, 12a, 13a, and 14a, which share the ground loads of the front and rear wheels FL, FR, RL, and RR. Further, as shown in FIG. 1, each of the suspension hydraulic cylinders 11, 12, 13, 14 is assembled with each of the hydraulic sensors PS1, PS2, PS3, PS4 for detecting the internal pressure. The sensors PS1, PS2, PS3 and PS4 are electrically connected to the electric control unit ECU.

  The bouncing suppressor 20 is a behavior suppressing unit that suppresses the operation of each suspension hydraulic cylinder 11, 12, 13, 14 in a state where bouncing, which is one of the behaviors of the vehicle body, occurs. Bouncing control cylinders 21, 22, 23, 24 connected to the ports 11a, 12a, 13a, 14a of the 11, 12, 13, 14 via pipes P1, P2, P3, P4, respectively. The cylinders 21, 22, 23, 24 are provided with pistons 21a, 22a, 23a, 24a having substantially the same pressure receiving area.

  The pistons 21a, 22a, 23a, 24a are integrated, and a hydraulic chamber 25 is provided on the back thereof. The hydraulic chamber 25 communicates with a hydraulic chamber 26a of an accumulator 26 (which can be implemented by a gas type or a spring type) that also functions as a spring element, and a damping element that suppresses vibration of the spring element is provided in the communication path. A variable aperture 27 is interposed.

  The rolling suppressor 30 is a behavior suppressing means for suppressing the operation of each suspension hydraulic cylinder 11, 12, 13, 14 in a state where rolling, which is one of the behaviors of the vehicle body, is generated. The rolling control cylinders 31, 32, 33, and 34 connected to the ports 11a, 12a, 13a, and 14a of the 11, 12, 13, and 14 via pipes P1, P2, P3, and P4, respectively. The cylinders 31, 32, 33, and 34 include pistons 31a, 32a, 33a, and 34a having substantially the same pressure receiving area.

  Each rolling control cylinder 31, 34 is connected to both suspension hydraulic cylinders 11, 14 located diagonally (front left and right rear), and each operation thereof is in reverse phase (piston 31a associated with increase / decrease in hydraulic pressure). , 34a are reversed so that the left and right rolling control cylinder 30A is configured. In the left and right pair rolling control cylinder 30A, the pistons 31a and 34a of both the rolling control cylinders 31 and 34 are integrated and shared.

  On the other hand, the rolling control cylinders 32 and 33 are connected to both suspension hydraulic cylinders 12 and 13 located diagonally (front right and rear left), and are connected so that their operations are in opposite phases. The left and right pair rolling control cylinder 30B is configured. In the left and right pair rolling control cylinder 30B, pistons 32a and 33a of both rolling control cylinders 32 and 33 are integrated and shared.

  The left and right paired rolling control cylinders 30A, 30B are in the same phase on the left and right (for example, both pistons 31a, 34a and 32a, 33a are on the right side of the figure when the hydraulic pressure of the left suspension hydraulic cylinders 11, 13 is increased. The pistons 31 a, 34 a and 32 a, 33 a are connected via a connecting rod 35.

  The connecting rod 35 extends outside the cylinder, and has one end of a coil spring 36 that functions as a spring element at its extended end and one end of a shock absorber 37 that functions as a damping element that controls vibration of the spring element. And the operation (axial movement) is suppressed by the coil spring 36 and the shock absorber 37. In this embodiment, the other ends of the coil spring 36 and the shock absorber 37 are fixed so as not to move.

  The pitching suppressor 40 is a behavior suppressing means that suppresses the operation of each suspension hydraulic cylinder 11, 12, 13, 14 in a state where pitching, which is one of the behaviors of the vehicle body, is generated. Pitching control cylinders 41, 42, 43, 44 connected to the ports 11 a, 12 a, 13 a, 14 a of 11, 12, 13, 14 via pipes P 1, P 2, P 3, P 4, respectively. The cylinders 41, 42, 43, and 44 are provided with pistons 41a, 42a, 43a, and 44a having substantially the same pressure receiving area.

  The pitching control cylinders 41 and 44 are connected to both suspension hydraulic cylinders 11 and 14 located diagonally (front left and rear right), and are connected so that their operations are in opposite phases. An anti-pitching control cylinder 40A is configured. In the front / rear pair pitching control cylinder 40A, the pistons 41a, 44a of both the pitching control cylinders 41, 44 are integrated and shared.

  On the other hand, the pitching control cylinders 42 and 43 are connected to both suspension hydraulic cylinders 12 and 13 located diagonally (front right and rear left), and are connected so that their operations are in opposite phases. The front / rear pair pitching control cylinder 40B is configured. In the front / rear pair pitching control cylinder 40B, the pistons 42a and 43a of both the pitching control cylinders 42 and 43 are integrated and shared.

  Each of the front / rear pair pitching control cylinders 40A, 40B has the same front / rear phase (for example, both the pistons 41a, 44a and 42a, 43a are on the right side of the figure when the hydraulic pressure of the front suspension hydraulic cylinders 11, 12 is increased). The pistons 41 a, 44 a and 42 a, 43 a are connected via a connecting rod 45.

  The connecting rod 45 extends out of the cylinder, and has one end of a coil spring 46 that functions as a spring element at the extended end portion and one end of a shock absorber 47 that functions as a damping element that controls vibration of the spring element. And the operation (axial movement) is suppressed by the coil spring 46 and the shock absorber 47. In this embodiment, the other ends of the coil spring 46 and the shock absorber 47 are fixed so as not to move.

  The ground load changing device 50 is controlled by the electric control unit ECU to change the ground load shared by the suspension hydraulic cylinders 11, 12, 13, and 14, and each suspension hydraulic cylinder 11, 12, 13 and 14 are provided with ground load control cylinders 51, 52, 53 and 54 connected to the ports 11a, 12a, 13a and 14a via pipes P1, P2, P3 and P4, respectively. , 52, 53, 54 are provided with pistons 51a, 52a, 53a, 54a having substantially the same pressure receiving area.

  The ground load control cylinders 52 and 54 are connected to both suspension hydraulic cylinders 12 and 14 located on the right side (right front and right rear), and are connected so that their operations are in opposite phases. A grounding load control cylinder 50A is configured. In the right ground contact load control cylinder 50A, the pistons 52a and 54a of both the ground load control cylinders 52 and 54 are integrated and shared.

  On the other hand, the ground load control cylinders 51 and 53 are connected to both suspension hydraulic cylinders 11 and 13 located on the left side (front left and rear left), and are connected so that their respective operations are in reverse phase. The left ground contact load control cylinder 50B is configured. In the left ground contact load control cylinder 50B, the pistons 51a and 53a of both the ground load control cylinders 51 and 53 are integrated and shared.

  The right-side anti-loading load control cylinder 50A and the left-side anti-load-control cylinder 50B are in the same phase diagonally (for example, both when the hydraulic pressure of the right front suspension hydraulic cylinder 12 and the left rear suspension hydraulic cylinder 13 becomes high. The pistons 51a, 53a and 52a, 54a are arranged so as to be pushed to the right in the figure), and the pistons 51a, 53a and 52a, 54a are connected via a connecting rod 55.

  The connecting rod 55 extends outside the cylinder, and has one end of a coil spring 56 that functions as a spring element at the extended end portion and one end of a shock absorber 57 that functions as a damping element that controls vibration of the spring element. And the operation (axial movement) is suppressed by the coil spring 56 and the shock absorber 57, and the operation (axial movement) is performed by the actuator 58 connected to the other end of the coil spring 56 and the shock absorber 57. It is supposed to be suppressed.

  The actuator 58 applies an operating force to the ground load control cylinders 51 to 54 via the coil spring 56 and the shock absorber 57, and the operation is controlled by the hydraulic control device 60. The actuator 58 includes a cylinder 58a whose supply and discharge of hydraulic fluid is controlled by the hydraulic control device 60, a piston 58b that is assembled in the cylinder 58a so as to be able to reciprocate, and a cylinder 58a that is integrated with the piston 58b. And a rod 58c that applies operating force to the coil spring 56 and the other end of the shock absorber 57, and a pair of oil chambers R1 and R2 are formed in the cylinder 58a by a piston 58b. The cylinder 58a is assembled with hydraulic pressure sensors PS5 and PS6 for detecting the pressures of the oil chambers R1 and R2, and the hydraulic pressure sensors PS5 and PS6 are electrically connected to the electric control unit ECU. .

  The hydraulic control device 60 includes a pump 61 capable of supplying forward and reverse rotation to the oil chambers R1 and R2 of the actuator 58, an electric motor 62 capable of rotating forward and reverse, and each oil chamber. A four-port two-position switching valve 63 that is interposed in a connection passage between R1, R2 and the pump 61 and communicates and shuts off between them, and a bypass passage that connects both ports of the pump 61. A two-port two-position on-off valve 64 that opens and closes is provided. In the hydraulic control device 60, the operations of the electric motor 62, the 4-port 2-position switching valve 63, the 2-port 2-position opening / closing valve 64, and the like are controlled by the electric control device ECU via the drive circuit 70. .

  The electric control unit ECU is electrically connected to the hydraulic pressure sensors PS1 to PS6 and the drive circuit 70, and also includes a motor current sensor S1, a steering angle sensor S2, a vehicle speed sensor S3, each wheel tire pressure sensor S4, and each wheel brake hydraulic pressure. It is electrically connected to a sensor S5, each wheel speed sensor S6, a yaw rate sensor S7, a lateral acceleration sensor S8, and the like.

  The electric control unit ECU includes a microcomputer having a CPU, a ROM, a RAM, an interface, and the like, and the CPU of the electric control unit ECU is illustrated when an ignition switch (not shown) is turned on. 3 to 13 are repeatedly executed every predetermined calculation cycle (for example, 8 msec), and the electric motor 62, the 4-port 2-position switching valve 63, and the 2-port 2-position opening / closing in the hydraulic control device 60 are executed. The operation of the valve 64 and the like is controlled.

  The electric control unit ECU outputs a VSC control signal during VSC control of a known VSC device (vehicle stability control device) that suppresses understeer and oversteer when the vehicle turns. The electric control unit ECU is configured to be able to control the operation of a known steering gear ratio variable mechanism (VGRS) that varies the steering gear ratio in accordance with the vehicle speed.

  In the vehicle suspension apparatus according to the first embodiment configured as described above, when the ignition switch is in the ON state, the CPU of the electric control unit ECU controls the hydraulic control unit 60 based on the signal from each sensor. The electric motor 62, the 4-port 2-position switching valve 63, and the 2-port 2-position opening / closing valve 64 are controlled to control the ground loads of the front, rear, left and right wheels FL, FR, RL, RR.

  The control of the ground load is performed by the CPU of the electric control unit ECU repeatedly executing the main routine shown in FIG. 3 every predetermined calculation cycle (for example, 8 msec). 3 is started at step 101, control presence / absence determination / initialization processing is executed at step 200, tire air pressure control processing is executed at step 300, and VSC cooperative control processing is executed at step 400. In step 500, the crossing braking control process is executed, in step 600, the vehicle speed sensitivity / VGRS coordination / control speed limit process is executed, in step 700, the yaw rate control process is executed, and in step 800, the actuator target difference is executed. The pressure calculation process is executed, the motor control process is executed in step 900, and the process is temporarily ended in step 102. .

  When the CPU of the electric control unit ECU executes the control presence / absence determination / initialization process in step 200 of FIG. 3, the subroutine shown in FIG. 4 is executed. Specifically, the CPU of the electric control unit ECU starts processing in step 201, sets the flag F to “0” in step 202, and measures the electric resistance value R of the electric motor 62 in step 203. Remember. The electric resistance value R is measured from the detection signal of the motor current sensor S1 by passing a minute current through the electric motor 62. When the electric motor 62 is disconnected and cannot be energized, the electric resistance value R is larger than the set value Ro.

  For this reason, when the electric motor 62 is disconnected (at the time of failure), the CPU of the electric control unit ECU determines “Yes” in step 204, and in step 205, the 4-port 2-position switching valve 63. 3 is output to the drive circuit 70, the process returns to step 102 in FIG. Therefore, when the electric motor 62 is disconnected and the operation of the actuator 58 cannot be controlled by the hydraulic control device 60, the actuator 58 is hydraulically locked by the 4-port 2-position switching valve 63 to disable the operation. .

  On the other hand, when the electric motor 62 is not disconnected, the CPU of the electric control unit ECU makes a “No” determination at step 204 and detects and stores the steering angle from the detection signal of the steering angle sensor S2 at step 206. To do. At this time, if the steering angle is larger than the threshold value 1 (for example, about 3 degrees), “Yes” is determined in Step 207, and the vehicle speed is detected from the detection signal of the vehicle speed sensor S 3 and stored in Step 208. At this time, if the vehicle speed is larger than the threshold value 2 (for example, about 6 km / h), “Yes” is determined in Step 209, Steps 210, 211, and 212 are executed, and then Step 213 is executed. Return to the main routine.

  Further, if the steering angle is equal to or smaller than the threshold 1 at the time of execution of step 207 described above (substantially straight running), the CPU of the electric control unit ECU determines “No” in step 207, and step 214. , 215, the process returns to step 102 in FIG. Further, if the vehicle speed is equal to or lower than the threshold value 2 when the above-described step 209 is executed (the vehicle speed is equal to or lower than the vehicle speed at which the effect due to the change in the ground load is effectively obtained), the CPU of the electric control unit ECU determines “No” in step 209 And after executing Steps 214 and 215, the process returns to Step 102 of FIG.

  By the way, in step 210, the CPU of the electric control unit ECU detects each suspension cylinder hydraulic pressure from the detection signal of each hydraulic sensor PS1, PS2, PS3, PS4 provided in each suspension hydraulic cylinder 11, 12, 13, 14 respectively. In step 211, the ground load value of each wheel is calculated from each suspension cylinder hydraulic pressure and stored. In step 212, the right rear wheel ground load value and the left rear of the ground load values of each wheel are stored. The rear wheel ground load value is calculated from the wheel ground load value and stored. The contact load value of each wheel in step 211 is calculated by adding up the pressure receiving areas of the suspension cylinder hydraulic pressures and the suspension hydraulic cylinders 11, 12, 13, and 14. Further, the rear wheel ground load value in step 212 is calculated by adding the right rear wheel ground load value and the left rear wheel ground load value.

  In step 214, the CPU of the electric control unit ECU outputs an opening signal for opening the 2-port 2-position opening / closing valve 64 to the drive circuit 70. In step 215, both hydraulic pressures provided in the cylinder 58a of the actuator 58 are output. The sensors PS5 and PS6 are reset and initialized. Therefore, at this time, the bypass passage connecting both ports of the pump 61 is opened, and free operation of the piston 58b and the rod 58c in the actuator 58 is allowed. Therefore, at this time, by allowing free operation of each of the ground load control cylinders 51 to 54, it is possible to cut off transmission of vibration input from the road surface and improve riding comfort.

  In addition, since the hydraulic pressure sensors PS5 and PS6 are reset and initialized in the execution of step 215, it is possible to prevent neutral displacement of the hydraulic pressure sensors PS5 and PS6. Further, when the vehicle speed is less than or equal to the threshold value 2 in the execution of steps 208 and 209 (when the effect due to the change in the ground load cannot be obtained effectively), steps 300 to 900 in FIG. In addition, it is possible to suppress energy consumption by eliminating the operation, and to improve the durability of the device.

  Further, when the CPU of the electric control unit ECU executes the tire air pressure control process at step 300 in FIG. 3, the subroutine shown in FIG. 5 is executed. Specifically, the CPU of the electric control unit ECU starts processing in step 301, and in step 302, the tire pressure of each wheel is detected and stored from the detection signal of each wheel tire pressure sensor S4. At this time, if the tire air pressure of each wheel is equal to or higher than a threshold value 3 (for example, a normal lower limit value of about 150 kPa), the CPU of the electric control unit ECU sets “No” in Steps 303, 304, 305, and 306, respectively. After the determination, step 307 is executed, and the process returns to the main routine of FIG.

  At this time, if the tire air pressure of each wheel other than the tire pressure of the left rear wheel is greater than or equal to the threshold 3, the CPU of the electric control unit ECU determines “No” in each of steps 303, 304, and 305, respectively. , “Yes” is determined in Step 306, the target ground load value of the left rear wheel is set to zero in Step 308, the flag F is set to “1” in Step 309, and Step 307 is executed. Returning to the main routine of FIG.

  At this time, if the tire air pressure of the left and right front wheels is greater than or equal to the threshold value 3 and the tire air pressure of the left and right rear wheels is less than the threshold value 3, the CPU of the electric control unit ECU determines “No” in steps 303 and 304, respectively. After making a determination and determining “Yes” in steps 305 and 310, respectively, step 307 is executed, and the process returns to the main routine of FIG.

  At this time, if the tire air pressure of each wheel other than the tire air pressure of the right rear wheel is equal to or greater than the threshold value 3, the CPU of the electric control unit ECU determines “No” in each of steps 303 and 304, respectively. “Yes” is determined in 305, “No” is determined in step 310, and the target ground load value of the left rear wheel is determined in step 311 as the rear wheel ground load value (the ground calculated in step 212 of FIG. 4). Load value) and the flag F is set to "1" in step 312, then step 307 is executed, and the process returns to the main routine of FIG.

  At this time, if the tire air pressure of the right front wheel and the left rear wheel is greater than or equal to the threshold value 3 and the tire air pressure of the left front wheel is less than the threshold value 3, the CPU of the electric control unit ECU determines “No” in each step 303. In Step 304, “Yes” is determined. In Step 313, “No” is determined. In Step 311, the target ground load value of the left rear wheel is set to the above-described rear wheel ground load value. After setting the flag F to “1” in step 312, step 307 is executed, and the process returns to the main routine of FIG.

  At this time, if the tire pressure of the right front wheel is greater than or equal to the threshold value 3 and the tire pressures of the left front wheel and the left rear wheel are less than the threshold value 3, the CPU of the electric control unit ECU determines “No” in step 303. After making a determination and determining “Yes” in steps 304 and 313, respectively, step 307 is executed and the process returns to the main routine of FIG.

  At this time, if the tire air pressure of the left and right front wheels is less than the threshold 3, the CPU of the electric control unit ECU determines “Yes” in steps 303 and 314, respectively, and then executes step 307. Return to the main routine. At this time, if the tire pressure of the right front wheel is less than threshold 3, the tire pressure of the left front wheel is greater than or equal to threshold 3, and the tire pressure of the right rear wheel is less than threshold 3, the CPU of the electric control unit ECU In Step 303, “Yes” is determined. In Step 314, “No” is determined. In Step 315, “Yes” is determined. Then, Step 307 is executed, and the process returns to the main routine of FIG.

  At this time, if the tire pressure of the right front wheel is less than the threshold value 3 and the tire pressures of the left front wheel and the right rear wheel are greater than or equal to the threshold value 3, the CPU of the electric control unit ECU determines “Yes” in step 303. In Steps 314 and 315, “No” is determined. In Step 316, the target ground load value of the left rear wheel is set to zero. In Step 317, the flag F is set to “1”. Step 307 is executed, and the process returns to the main routine of FIG.

  Further, when the CPU of the electric control unit ECU executes the VSC cooperative control process in step 400 of FIG. 3, the subroutine shown in FIG. 6 is executed. Specifically, the CPU of the electric control unit ECU starts processing in step 401, and in step 402, detects and stores a VSC control signal (a signal output by the electric control unit ECU itself during VSC control). At this time, if the VSC control is not being executed, the CPU of the electric control unit ECU determines “No” in step 403, then executes step 404, and returns to the main routine of FIG. When the VSC control is being executed, the CPU of the electric control unit ECU determines “Yes” in step 403, and then, in step 405, determines the brake hydraulic pressure of each wheel from the detection signal of each wheel brake hydraulic pressure sensor S 5. Is detected and stored.

  At this time, if the brake hydraulic pressure of the left and right front wheels is equal to or less than a threshold value 4 (for example, about 1 MPa), the CPU of the electric control unit ECU determines “No” in steps 406 and 407, and then executes step 404. Then, the process returns to the main routine of FIG. At this time, if the brake hydraulic pressure of the right front wheel is less than or equal to the threshold value 4 and the brake hydraulic pressure of the left front wheel is greater than the threshold value 4, the CPU of the electric control unit ECU determines “No” in step 406 and step 407. In step 408, the target ground load value of the left rear wheel is set to zero. In step 409, the flag F is set to "1", and then step 404 is executed. Return to the main routine.

  Further, at this time, if the brake hydraulic pressure of the right front wheel is larger than the threshold value 4, the brake hydraulic pressure of the left rear wheel is larger than the threshold value 5 (for example, about 0.5 MPa), and the brake hydraulic pressure of the right rear wheel is less than the threshold value 5, The CPU of the electric control unit ECU determines “Yes” at step 406, determines “Yes” at step 410, determines “No” at step 411, and sets the target for the left rear wheel at step 408. After the ground load value is set to zero and the flag F is set to “1” in step 409, step 404 is executed, and the process returns to the main routine of FIG.

  At this time, if the brake oil pressure of the right front wheel is greater than the threshold value 4 and the brake oil pressure of the left and right rear wheels is greater than the threshold value 5, the CPU of the electric control unit ECU determines “Yes” in each step 406, 411, 412, respectively. ”Is executed, step 404 is executed, and the process returns to the main routine of FIG.

  At this time, if the brake oil pressure of the right front wheel is greater than the threshold value 4 and the brake oil pressure of the left rear wheel is less than or equal to the threshold value 5, the CPU of the electric control unit ECU determines “Yes” in step 406, It is determined as “No” in 410, the target ground load value of the left rear wheel is set to the above-mentioned rear wheel ground load value in Step 412, and the flag F is set to “1” in Step 413. Execute 404 and return to the main routine of FIG.

  Further, when the CPU of the electric control unit ECU executes the crossing braking control process in step 500 of FIG. 3, the subroutine shown in FIG. 7 is executed. Specifically, the CPU of the electric control unit ECU starts processing in step 501, and detects the brake hydraulic pressure of each wheel from the detection signal of each wheel brake hydraulic pressure sensor S5 (see FIG. 1) in step 502. Remember. At this time, if all the brake hydraulic pressures are zero, the CPU of the electric control unit ECU determines “Yes” in step 503, executes step 504, and returns to the main routine of FIG.

  If at least one brake hydraulic pressure is not zero, the CPU of the electric control unit ECU determines “No” in step 503 and then calculates the slip ratio (each wheel slip ratio) of each wheel in step 505. In step 506, the ground load value (each wheel ground load value) of each wheel is calculated and stored. In step 507, the friction coefficient of each road surface on which each wheel is grounded (each wheel surface) μ) is calculated and stored.

  Each wheel slip rate described above is calculated from the wheel speed obtained from the detection signal of each wheel speed sensor S6 (see FIG. 1) and the vehicle speed obtained from the detection signal of the vehicle speed sensor S1 (see FIG. 1). It is calculated by a relational expression of (wheel speed) / vehicle speed. Each wheel brake force described above includes the brake oil pressure of each wheel obtained from the detection signal of each wheel brake oil pressure sensor S5 (see FIG. 1) and the specifications of the brake device mounted on each wheel (piston area, pad μ, (Effective brake radius, tire effective radius) is calculated by a relational expression of brake force = brake hydraulic pressure × piston area × pad μ × effective brake radius ÷ tire effective radius. Each wheel ground contact load value is determined based on the pressure obtained from the detection signals of the hydraulic sensors PS1 to PS4 (see FIG. 1) provided in the suspension hydraulic cylinders 11 to 14 and the suspension hydraulic cylinders 11 to 14. It is calculated by integrating the pressure receiving area. Each wheel road surface μ described above is calculated from each wheel slip ratio and each wheel contact load value with reference to the map of FIG.

  By the way, when each wheel road surface μ is estimated and stored, the difference between the friction coefficient of the road surface on which the right front wheel is in contact (μ right front) and the friction coefficient of the road surface on which the left front wheel is in contact (μ left front) is a threshold value. The difference between the friction coefficient of the road surface on which the left front wheel is in contact (μ left front) and the friction coefficient of the road surface on which the right front wheel is in contact (μ right front) is 6 (for example, about 0.1) or less. If it is below, the CPU of the electric control unit ECU makes a “No” determination at Step 508, determines “No” at Step 509, executes Step 504, and returns to the main routine of FIG.

  At this time, the difference between the friction coefficient of the road surface on which the right front wheel is in contact (μ right front) and the friction coefficient of the road surface on which the left front wheel is in contact (μ left front) is a threshold value 6 or less, and the left front wheel is in contact with the ground. The difference between the friction coefficient of the road surface (μ left front) and the friction coefficient of the road surface where the right front wheel is in contact (μ right front) is greater than the threshold value 6, and the friction coefficient of the road surface where the left front wheel is in contact (μ left front) ) And the friction coefficient (μ left rear) of the road surface on which the left rear wheel is in contact is equal to or greater than a threshold value 7 (for example, about 0.1), the CPU of the electric control unit ECU at step 508 “No” is determined, “Yes” is determined in Step 509, “No” is determined in Step 510, and the target ground load value of the left rear wheel is changed to the above-described rear wheel ground load value in Step 511. After setting the flag F to “1” in step 512, execute step 504. Then, returns to the main routine shown in FIG.

  At this time, the difference between the friction coefficient of the road surface on which the right front wheel is in contact (μ right front) and the friction coefficient of the road surface on which the left front wheel is in contact (μ left front) is a threshold value 6 or less, and the left front wheel is in contact with the ground. The difference between the friction coefficient of the road surface (μ left front) and the friction coefficient of the road surface where the right front wheel is in contact (μ right front) is greater than the threshold value 6, and the friction coefficient of the road surface where the left front wheel is in contact (μ left front) ) And the friction coefficient of the road surface on which the left rear wheel is in contact (μ left rear) is smaller than the threshold value 7, the CPU of the electric control unit ECU makes a “No” determination at step 508, and then proceeds to step 509. "Yes" is determined at step 510, "Yes" is determined at step 510, and the target ground load value of the left rear wheel is determined at step 513. The above-mentioned rear wheel ground load value x μ right rear / (μ right rear + μ After setting the flag F to “1” in step 512, step 50 The execution and returns to the main routine of FIG. 3.

  At this time, the difference between the friction coefficient of the road surface to which the right front wheel is grounded (μ right front) and the friction coefficient of the road surface to which the left front wheel is grounded (μ left front) is larger than the threshold value 6, and the right front wheel is grounded. If the difference between the friction coefficient of the road surface (μ right front) and the friction coefficient of the road surface where the right rear wheel is in contact (μ right rear) is smaller than the threshold value 7, the CPU of the electric control unit ECU at step 508 “Yes” is determined, “Yes” is determined in Step 514, and the target ground load value of the left rear wheel is set to the rear wheel ground load value × μ right rear / (μ right rear + μ left rear) in Step 513. After setting and setting the flag F to “1” in step 512, step 504 is executed, and the process returns to the main routine of FIG.

  At this time, the difference between the friction coefficient of the road surface to which the right front wheel is grounded (μ right front) and the friction coefficient of the road surface to which the left front wheel is grounded (μ left front) is larger than the threshold value 6, and the right front wheel is grounded. If the difference between the friction coefficient of the road surface (μ right front) and the friction coefficient of the road surface where the right rear wheel is in contact (μ right rear) is greater than or equal to the threshold value 7, the CPU of the electric control unit ECU proceeds to step 508. "Yes" is determined, "No" is determined in step 514, the target ground load value of the left rear wheel is set to zero in step 515, and the flag F is set to "1" in step 512 Thereafter, step 504 is executed, and the process returns to the main routine of FIG.

  Further, when the CPU of the electric control unit ECU executes the vehicle speed response / VGRS coordination / control speed limiting process in step 600 of FIG. 3, the subroutine shown in FIG. 9 is executed. Specifically, the CPU of the electric control unit ECU starts processing in step 601, detects and stores the vehicle speed from the detection signal of the vehicle speed sensor S 3 (see FIG. 1) in step 602, and in step 603. The gear ratio of VGRS is acquired from the vehicle speed and stored, and in step 604, the target roll stiffness front wheel distribution value is determined and stored according to the vehicle speed and VGRS gear ratio described above with reference to the map of FIG.

  At this time, if the vehicle speed is greater than the threshold value 9 (for example, about 60 km / h), the CPU of the electric control unit ECU determines “Yes” in step 605 and corrects the target roll stiffness front wheel distribution value in step 606. After calculating and storing, step 607 is executed, and the process returns to the main routine of FIG. The correction calculation of the target roll stiffness front wheel distribution value in step 606 described above is performed by calculating the current target roll stiffness front wheel distribution value obtained by executing step 604 and the previous target roll stiffness obtained by executing step 604. This is done by adding the rigid front wheel distribution values to ½ (averaged).

  At this time, the vehicle speed is equal to or less than the threshold value 9, and the current target roll stiffness front wheel distribution value obtained by the execution of step 604 described above is the previous target roll stiffness front wheel distribution value obtained by the previous execution of step 604. If it is above, CPU of electric control unit ECU will determine with "No" in step 605, will determine with "No" in step 608, will perform step 607, and will return to the main routine of FIG.

  At this time, the vehicle speed is equal to or less than the threshold value 9, and the current target roll stiffness front wheel distribution value obtained by the execution of step 604 described above is the previous target roll stiffness front wheel distribution value obtained by the previous execution of step 604. If smaller, the CPU of the electric control unit ECU determines “No” in step 605, determines “Yes” in step 608, and corrects and calculates the current target roll stiffness front wheel distribution value in step 606. Then, step 607 is executed to return to the main routine of FIG.

  Further, when the CPU of the electric control unit ECU executes the yaw rate control process in step 700 of FIG. 3, the subroutine shown in FIG. 11 is executed. Specifically, the CPU of the electric control unit ECU starts processing in step 701, detects and stores the vehicle speed from the detection signal of the vehicle speed sensor S3 (see FIG. 1) in step 702, and in step 703. The steering angle is detected and stored from the detection signal of the steering angle sensor S2 (see FIG. 1), and the target yaw rate is calculated in step 704. This target yaw rate is calculated from the above vehicle speed and steering angle according to the relational expression of target yaw rate = vehicle speed × steering angle × constant.

  The CPU of the electric control unit ECU detects and stores the actual yaw rate (actual yaw rate) from the detection signal of the yaw rate sensor S7 (see FIG. 1) in step 705, and in step 706, the yaw rate deviation, that is, The difference between the target yaw rate and the actual yaw rate is calculated and stored. At this time, if the absolute value of the deviation is larger than a threshold value 8 (for example, about 0.1 deg / s), the CPU of the electric control unit ECU determines “Yes” in step 707, and in FIG. After correcting the target roll stiffness front wheel distribution value according to the yaw rate deviation with reference to the map, step 709 is executed, and the process returns to the main routine of FIG. At this time, if the absolute value of the deviation is equal to or less than the threshold value 8, the CPU of the electric control unit ECU determines “No” in step 707, executes step 709, and returns to the main routine of FIG. .

  When the CPU of the electric control unit ECU executes the actuator target differential pressure calculation process at step 800 in FIG. 3, the subroutine shown in FIG. 13 is executed. Specifically, the CPU of the electric control unit ECU starts processing in step 801 and determines in step 802 whether or not the flag F is “1”. At this time, if the flag F is “1”, the CPU of the electric control unit ECU determines “Yes” in step 802, executes steps 803, 804, 805, and then executes step 806. Return to 3 main routine.

  In step 803 described above, the CPU of the electric control unit ECU performs the target ground load value of the left rear wheel obtained by executing the subroutine shown in FIGS. 5 to 7 and the actual ground load of the left rear wheel at this time. Value (actual contact load value calculated by integrating the pressure obtained from the detection signal of the hydraulic sensor PS3 (see FIG. 1) provided in the suspension hydraulic cylinder 13 of the left rear wheel and the pressure receiving area of the suspension hydraulic cylinder 13) ) Is calculated and stored.

  In step 804 described above, the target actuator thrust (force in the axial direction applied to the rod 58c of the actuator 58) required for the CPU of the electric control unit ECU to eliminate the deviation calculated in step 803 is used as the target actuator. In step 805, the target actuator differential pressure (the differential pressure between the oil chambers R1, R2 in the actuator 58) is calculated and stored from the target actuator thrust.

  Further, if the flag F is “0” at the time of executing step 802 described above, the CPU of the electric control unit ECU determines “No” at step 802 and executes steps 807, 808, and 809, and then Steps 805 and 806 are executed, and the process returns to the main routine of FIG.

  In step 807 described above, the CPU of the electric control unit ECU detects and stores the actual lateral acceleration from the detection signal of the lateral acceleration sensor S8 (see FIG. 1). In step 808, the actual lateral acceleration and vehicle specifications are detected. From left and right (vehicle sprung mass, center of gravity height, tread), the left and right load moving amount is estimated by the following relational expression: load moving amount = vehicle spring top mass × lateral acceleration × center of gravity height ÷ tread. In step 809 described above, the CPU of the electric control unit ECU performs the target roll stiffness front wheel distribution value obtained by executing the subroutine shown in FIG. 9 or FIG. 11 and the left and right load movement amounts obtained in step 808. From the pressure receiving area of the piston rod of the suspension hydraulic cylinders 11 to 14 and the pressure receiving area of the pistons 51a to 54a of the ground load change device 50, the target actuator thrust is calculated as: target actuator thrust = (target roll rigidity front wheel distribution value × 2-1) × (left and right Load movement amount) × (piston area of ground load changing device 50) ÷ (piston rod pressure receiving area of suspension hydraulic cylinder) is calculated and stored.

  Further, when the CPU of the electric control unit ECU executes the motor control process in step 900 of FIG. 3, the subroutine shown in FIG. 14 is executed. Specifically, the CPU of the electric control unit ECU starts processing at step 901, executes steps 902 to 906, then executes step 907, and returns to the main routine of FIG.

  In step 902 described above, the CPU of the electric control unit ECU detects and stores the actual oil pressures of the oil chambers R1 and R2 in the actuator 58 from the detection signals of the oil pressure sensors PS5 and PS6 (see FIG. 1). In step 903, the actual hydraulic pressure difference (actual differential pressure) between the oil chambers R1 and R2 is calculated and stored. In step 904 described above, the CPU of the electric control unit ECU calculates and stores the deviation between the target differential pressure obtained in step 805 in FIG. 12 and the actual differential pressure obtained in step 903. In step 905 described above, the motor current (driving direction and driving force) of the electric motor 62 is calculated and stored in a relational expression of motor current = deviation × constant in accordance with the deviation between the target differential pressure and the actual differential pressure. In step 906 described above, the CPU of the electric control unit ECU outputs a drive signal with the motor current obtained in step 905 to the drive circuit 70 of the electric motor 62.

  As is apparent from the above description, in the vehicle suspension device of the first embodiment, for example, the tire air pressure of all the wheels is in a normal value (a value that is greater than or equal to the threshold value 3) and the left rear wheel RL is When the tire air pressure becomes smaller than the threshold 3, steps 302, 303, 304, 305, 306, 308, and 309 are executed in the subroutine of FIG. 5, and steps 802, 803, 804, and 805 are executed in the subroutine of FIG. All steps are executed in the subroutine of FIG. 14, and the electric motor 62 is driven by the motor current (drive direction and driving force) obtained in step 905 of FIG.

  Therefore, as shown in FIGS. 15A and 15B, the connecting rod 55 of the ground load changing device 50 is moved from the state shown in FIG. 15A to the state shown in FIG. When pressed, the ground load can be moved from the right front wheel FR to the left front wheel FL for the left and right front wheels, and the ground load can be moved from the left rear wheel RL to the right rear wheel RR for the left and right rear wheels. Therefore, it is possible to reduce the contact load of the left rear wheel RL in which the tire air pressure is smaller than the threshold 3, and reduce the damage of the tire mounted on the left rear wheel RL. In addition, in FIG. 15, the magnitude | size of each grounding load was displayed with the magnitude | size of the circle according to each wheel FL, FR, RL, RR.

  When the tire pressure of the right front wheel FR becomes smaller than the threshold 3, steps 302, 303, 314, 315, 316, and 317 are executed in the subroutine of FIG. 5, and steps 802, 803 and 317 are executed in the subroutine of FIG. 804 and 805 are executed, and all the steps are executed in the subroutine of FIG. 14 to obtain the same operation as that described above, and the ground contact of the right front wheel FR in which the tire air pressure is smaller than the threshold value 3 is obtained. It is possible to reduce the load and reduce the damage to the tire mounted on the right front wheel FR.

  On the other hand, when the tire air pressure of the right rear wheel RR becomes smaller than the threshold 3, steps 302, 303, 304, 305, 310, 311 and 312 are executed in the subroutine of FIG. 5, and step 802 is executed in the subroutine of FIG. , 803, 804, 805 are executed, all the steps are executed in the subroutine of FIG. 14, and the electric motor 62 is driven by the motor current (drive direction and driving force) obtained in step 905 of FIG. The

  For this reason, as shown in FIGS. 15A and 15C, the connecting rod 55 of the ground load changing device 50 is moved from the state shown in FIG. 15A to the state shown in FIG. When pressed, the ground load can be moved from the left front wheel FL to the right front wheel FR in the left and right front wheels, and the ground load can be moved from the right rear wheel RR to the left rear wheel RL in the left and right rear wheels. Therefore, it is possible to reduce the contact load of the right rear wheel RR in which the tire air pressure is smaller than the threshold 3, and to reduce damage to the tire mounted on the right rear wheel RR.

  When the tire air pressure of the left front wheel FL becomes smaller than the threshold value 3, steps 302, 303, 304, 313, 311 and 312 are executed in the subroutine of FIG. 5, and steps 802, 803 and 312 are executed in the subroutine of FIG. Steps 804 and 805 are executed, and all the steps are executed in the subroutine of FIG. 14, and the same operation as the above-described operation can be obtained, and the ground contact of the left front wheel FL in which the tire air pressure becomes smaller than the threshold value 3 It is possible to reduce the load and reduce the damage to the tire mounted on the left front wheel FL.

  Further, in the vehicle suspension device of the first embodiment, for example, a rear wheel skid occurs during VSC control during a right turn, the brake oil pressure of the right front wheel FR is equal to or less than a threshold value 4, and the brake of the left front wheel FL is performed. When the hydraulic pressure exceeds the threshold value 4, steps 402, 403, 405, 406, 407, 408, and 409 are executed in the subroutine of FIG. 6, and steps 802, 803, 804, and 805 are executed in the subroutine of FIG. Then, all the steps are executed in the subroutine of FIG. 14, and the electric motor 62 is driven by the motor current (drive direction and driving force) obtained in step 905 of FIG.

  Therefore, at this time, the connecting rod 55 of the ground load changing device 50 is pressed by the actuator 58 toward the state shown in FIG. 16B, and the ground load is moved to the left front wheel FL and the right rear wheel RR. it can. Therefore, the braking force of the left front wheel FL increases, and the amount of side slip of the rear wheel can be reduced. In addition, in FIG. 16, the magnitude | size of each grounding load was displayed with the magnitude | size of the circle according to each wheel FL, FR, RL, RR.

  Further, a front wheel skidding occurs during VSC control during a left turn, the brake hydraulic pressure of the right front wheel FR is greater than threshold 4, the brake hydraulic pressure of the left rear wheel RL is greater than threshold 5, and the brake hydraulic pressure of the right rear wheel RR is When the threshold value is 5 or less, steps 402, 403, 405, 406, 410, 411, 408, and 409 are executed in the subroutine of FIG. 6, and steps 802, 803, 804, and 805 are executed in the subroutine of FIG. Then, all the steps are executed in the subroutine of FIG. 14, and the electric motor 62 is driven by the motor current (drive direction and driving force) obtained in step 905 of FIG.

  Therefore, at this time, the connecting rod 55 of the ground load changing device 50 is pressed toward the state of FIG. 17B by the actuator 58, and the ground load is moved to the left front wheel FL and the right rear wheel RR. it can. Therefore, the roll stiffness distribution is later and the tendency toward oversteering can be reduced, so that the amount of side slip of the front wheels can be reduced. In addition, in FIG. 17, the magnitude | size of each grounding load was displayed by the magnitude | size of the circle according to each wheel FL, FR, RL, RR.

  When the rear wheel side slip occurs during the VSC control during the left turn, the brake hydraulic pressure of the right front wheel FR is larger than the threshold value 4, and the brake hydraulic pressure of the left rear wheel RL becomes the threshold value 5 or less, the subroutine of FIG. Steps 402, 403, 405, 406, 410, 412, and 413 are executed, steps 802, 803, 804, and 805 are executed in the subroutine of FIG. 13, and all steps are executed in the subroutine of FIG. Thus, the electric motor 62 is driven by the motor current (driving direction and driving force) obtained in step 905 of FIG.

  Therefore, at this time, the connecting rod 55 of the ground load changing device 50 is pressed toward the state of FIG. 17C by the actuator 58, and the ground load is moved to the right front wheel FR and the left rear wheel RL. it can. Therefore, the braking force of the right front wheel FR is increased, and the side slip amount of the rear wheel can be reduced.

  Further, when the front wheel side slip occurs during the VSC control when turning right, the brake hydraulic pressure of the right front wheel FR is larger than the threshold value 4, and the brake hydraulic pressure of the left rear wheel RL becomes the threshold value 5 or less, the subroutine of FIG. Steps 402, 403, 405, 406, 410, 412, and 413 are executed, steps 802, 803, 804, and 805 are executed in the subroutine of FIG. 13, and all steps are executed in the subroutine of FIG. Thus, the electric motor 62 is driven by the motor current (driving direction and driving force) obtained in step 905 of FIG.

  Therefore, at this time, the connecting rod 55 of the ground load changing device 50 is pressed toward the state of FIG. 16C by the actuator 58, and the ground load is moved to the right front wheel FR and the left rear wheel RR. it can. Therefore, the roll stiffness distribution is later and the tendency toward oversteering can be reduced, so that the amount of side slip of the front wheels can be reduced.

  Further, in the vehicle suspension apparatus of the first embodiment, for example, when only the left front wheel FL is on a high μ road surface during braking control on a crossing road, steps 502, 503, and 505 are executed in the subroutine of FIG. , 506, 507, 508, 509, 510, 511, 512 are executed, steps 802, 803, 804, 805 are executed in the subroutine of FIG. 13, and all steps are executed in the subroutine of FIG. The electric motor 62 is driven by the motor current (driving direction and driving force) obtained in step 905 of FIG.

  Therefore, at this time, the connecting rod 55 of the ground load changing device 50 is pressed from the state shown in FIG. 15A to the state shown in FIG. 15C by the actuator 58, so that the right front wheel FR and the left rear wheel RL are grounded. The load can be moved, and the ground load of the left front wheel FL can be reduced. Therefore, it is possible to reduce the braking force of the left front wheel FL and avoid spin due to yaw moment imbalance.

  Further, during braking control on a straddle road, when the front and rear left wheels are on a high μ and the front and rear right wheels are on a low μ road surface, steps 502, 503, 505, 506, 507, 508, 509, 510, 513, and 512 are executed, steps 802, 803, 804, and 805 are executed in the subroutine of FIG. 13, and all the steps are executed in the subroutine of FIG. Driven by the motor current (drive direction and drive force) obtained in step 905.

  Therefore, at this time, the connecting rod 55 of the ground load changing device 50 is pressed by the actuator 58 toward the state shown in FIG. 15B, and the ground load is moved to the left front wheel FL and the right rear wheel RR. This can increase the contact load of the right rear wheel RR. Therefore, the product of the road surface μ and the ground load on the rear wheels can be made equal on the left and right, and the braking force on the rear wheels can be maximized.

  Further, during braking control on a crossing road, when the front and rear right wheels are on a high μ and the front and rear left wheels are on a low μ road surface, steps 502, 503, 505, 506, 507, 508, 514, 513 and 512 are executed, steps 802, 803, 804 and 805 are executed in the subroutine of FIG. 13, all steps are executed in the subroutine of FIG. 14, and the electric motor 62 is changed to step 905 in FIG. It is driven by the motor current (driving direction and driving force) obtained in.

  Therefore, at this time, the connecting rod 55 of the ground load changing device 50 is pressed by the actuator 58 toward the state shown in FIG. 15C, and the ground load is moved to the right front wheel FR and the left rear wheel RL. Thus, the ground load of the left rear wheel RL can be increased. Therefore, the product of the road surface μ and the ground load on the rear wheels can be made equal on the left and right, and the braking force on the rear wheels can be maximized.

  Further, during braking control on a straddle road, when only the right front wheel FR is on the high μ road surface, steps 502, 503, 505, 506, 507, 508, 514, 515, 512 are executed in the subroutine of FIG. Steps 802, 803, 804, and 805 are executed in the subroutine shown in FIG. 13, and all steps are executed in the subroutine shown in FIG. 14, so that the electric motor 62 obtains the motor current (step 905 shown in FIG. Drive direction and drive force).

  Therefore, at this time, the connecting rod 55 of the ground load changing device 50 is pressed by the actuator 58 toward the state shown in FIG. 15B, and the ground load is moved to the left front wheel FL and the right rear wheel RR. This can reduce the ground load of the right front wheel FR. Therefore, it is possible to reduce the braking force of the right front wheel FR and avoid spin due to yaw moment imbalance.

  In the vehicle suspension device of the first embodiment, for example, when the vehicle speed is greater than the threshold value 9 by turning right, steps 602, 603, 604, 605, and 606 are executed in the subroutine of FIG. Steps 802, 807, 808, 809, and 805 are executed in the subroutine of FIG. 13, and all the steps are executed in the subroutine of FIG. 14, so that the electric motor 62 is obtained by step 905 in FIG. Driven by current (drive direction and drive force).

  Therefore, at this time, the connecting rod 55 of the ground load changing device 50 is pressed by the actuator 58 toward the state of FIG. 16B, and the left front wheel FL (turning outer front wheel) and the right rear wheel RR (turning inner side). The ground load can be moved to the rear wheel. Therefore, at this time, the roll rigidity distribution is more than before, and an understeer tendency tends to occur, so that the stability of the vehicle can be improved. At this time, it is possible to reduce the change in behavior by slowing the control speed by executing step 606.

  Further, when the gear ratio of VGRS becomes small or the vehicle speed decreases during a right turn with the vehicle speed of 9 or less, steps 602, 603, 604, 605, 608, 606 are executed in the subroutine of FIG. 13 is executed, steps 802, 807, 808, 809, and 805 are executed in the subroutine of FIG. 13, all steps are executed in the subroutine of FIG. 14, and the electric motor 62 is obtained in step 905 of FIG. It is driven by the motor current (drive direction and drive force).

  Therefore, at this time, the connecting rod 55 of the ground load changing device 50 is pressed by the actuator 58 toward the state shown in FIG. 16C, and the right front wheel FR (turning inner front wheel) and the left rear wheel RL (turning outer side). The ground load can be moved to the rear wheel. Therefore, at this time, the roll rigidity distribution is later, and the steering tends to be oversteered, so that the maneuverability can be improved. At this time, it is possible to reduce the change in behavior by slowing the control speed by executing step 606.

  Further, when the gear ratio of VGRS increases or the vehicle speed increases during a right turn with the vehicle speed of 9 or less, steps 602, 603, 604, 605, and 608 are executed in the subroutine of FIG. Steps 802, 807, 808, 809, and 805 are executed in the subroutine of FIG. 13, and all steps are executed in the subroutine of FIG. 14, and the electric motor 62 is obtained in step 905 of FIG. Driven by motor current (drive direction and drive force).

  Therefore, at this time, the connecting rod 55 of the ground load changing device 50 is pressed by the actuator 58 toward the state of FIG. 16B, and the left front wheel FL (turning outer front wheel) and the right rear wheel RR (turning inner side). The ground load can be moved to the rear wheel. Therefore, at this time, the roll rigidity distribution is more than before, and an understeer tendency tends to occur, so that the stability of the vehicle can be improved. At this time, since step 606 is not executed, it is possible to increase the control speed and increase the control effect.

  Further, in the vehicle suspension device of the first embodiment, for example, when the absolute value of the deviation between the target yaw rate and the actual yaw rate becomes larger than the threshold value 8 during the right turn, all steps in the subroutine of FIG. 13 is executed, steps 802, 807, 808, 809, and 805 are executed in the subroutine of FIG. 13, all steps are executed in the subroutine of FIG. 14, and the electric motor 62 is obtained in step 905 of FIG. It is driven by the motor current (drive direction and drive force).

  Therefore, when the actual yaw rate is larger than the target yaw rate at this time, the connecting rod 55 of the ground load changing device 50 is pressed toward the state of FIG. 16B by the actuator 58, and the left front wheel FL (the turning outer front wheel). ) And the right rear wheel RR (turning inner rear wheel). Therefore, at this time, the roll stiffness distribution of the front wheels becomes large and tends to understeer, so that the actual yaw rate can be brought close to the target yaw rate.

  If the actual yaw rate is smaller than the target yaw rate at this time, the connecting rod 55 of the ground load changing device 50 is pressed toward the state of FIG. 16C by the actuator 58, and the right front wheel FR (turning inner front wheel). The ground load can be moved to the left rear wheel RL (turning outer rear wheel). Therefore, at this time, the roll stiffness distribution of the rear wheels is increased and an oversteer tendency is obtained, so that the actual yaw rate can be brought close to the target yaw rate.

  In the first embodiment, a shock absorber 57 as a damping means and a coil spring 56 as an elastic means are interposed between the ground load changing device 50 and the actuator 58. For this reason, it is possible to always allow and control the operation of the ground load control cylinders 51 to 54 by the coil spring 56 and the shock absorber 57, and the vibration input from the road surface is absorbed by the coil spring 56 and the shock absorber 57. It is possible to improve the ride comfort. In addition, it is also possible to implement without interposing the shock absorber 57 as the damping means and the coil spring 56 as the elastic means between the ground load changing device 50 and the actuator 58.

  Further, in the vehicle suspension device of the first embodiment, the bouncing suppressor 20 is activated during bouncing of the vehicle body, and the bouncing of the vehicle body is controlled. At this time, since the suspension hydraulic cylinders 11, 12, 13, and 14 perform substantially the same operation (compression operation), each control is performed from the ports 11a, 12a, 13a, and 14a via the pipes P1, P2, P3, and P4. The cylinders 21 to 24, 31 to 34, and 41 to 44 are supplied with substantially the same hydraulic pressure (high hydraulic pressure).

  By the way, at this time, the hydraulic pressures are balanced in the control cylinders 31, 34, 32, 33 and 41, 44, 42, 43 of the rolling suppressor 30 and the pitching suppressor 40, and the pistons 31a, 34a, 32a, 33a and 41a, 44a, 42a, 43a do not operate. On the other hand, in the bouncing suppressor 20, the pistons 21a, 22a, 23a, and 24a operate under the action of the accumulator 25 and the variable throttle 26, and the operations of the suspension hydraulic cylinders 11, 12, 13, and 14, that is, bouncing the vehicle body. Suppresses the impact from the road surface.

  Further, in the vehicle suspension apparatus of the first embodiment, the rolling suppressor 30 is operated during the rolling of the vehicle body, and the rolling of the vehicle body is controlled. At this time (for example, when the vehicle turns to the left), the right suspension hydraulic cylinders 12 and 14 perform substantially the same operation (compression operation), and the left suspension hydraulic cylinders 11 and 13 perform substantially the same operation. In order to perform (extension operation), substantially the same hydraulic pressure is applied to the control cylinders 22, 24, 32, 34 and 42, 44 from the ports 12a, 14a of the right suspension hydraulic cylinders 12, 14 via the pipes P2, P4. (High hydraulic pressure) is supplied and from the control cylinders 21, 23, 31, 33 and 41, 43 to the ports 11a, 13a of the left suspension hydraulic cylinders 11, 13 via the pipes P1, P3. The same oil pressure (low oil pressure) is supplied.

  By the way, at this time, the hydraulic pressures are balanced in the control cylinders 21, 24, 22, 23 and 41, 44, 42, 43 of the bouncing suppressor 20 and the pitching suppressor 40, and the pistons 21a, 24a, 22a, 23a 41a, 44a, 42a, 43a does not operate. On the other hand, in the rolling suppressor 30, pistons 31a, 34a and 32a, 33a connected by the connecting rod 35 operate under the action of the coil spring 36 and the shock absorber 37, and the suspension hydraulic cylinders 11, 12, 13 and 14, that is, rolling of the vehicle body is suppressed.

  Further, in the vehicle suspension device of the first embodiment, the pitching suppressor 40 is operated during the pitching of the vehicle body to control the pitching of the vehicle body. At this time (for example, when the vehicle is dive), the front suspension hydraulic cylinders 11 and 12 perform substantially the same operation (compression operation), and the rear suspension hydraulic cylinders 13 and 14 operate approximately the same. In order to perform (extension operation), substantially the same hydraulic pressure is applied to the control cylinders 21, 22, 31, 32 and 41, 42 from the ports 11a, 12a of the both suspension hydraulic cylinders 11, 12 via the pipes P1, P2. (High hydraulic pressure) is supplied to the ports 13a, 14a of the rear suspension hydraulic cylinders 13, 14 from the control cylinders 23, 24, 33, 34 and 43, 44 via the pipes P3, P4. Approximately the same hydraulic pressure (low hydraulic pressure) is supplied.

  By the way, at this time, the hydraulic pressures are balanced in the control cylinders 21, 24, 22, 23 and 31, 34, 32, 33 of the bouncing suppressor 20 and the rolling suppressor 30, and the pistons 21a, 24a, 22a, 23a 31a, 34a, 32a and 33a do not operate. On the other hand, in the pitching suppressor 40, the pistons 41a, 44a and 42a, 43a connected by the connecting rod 45 operate under the action of the coil spring 46 and the shock absorber 47, and the suspension hydraulic cylinders 11, 12, 13, 14, that is, the pitching of the vehicle body is suppressed.

  In the vehicle suspension device of the first embodiment, when the vehicle is torsionally input on rough terrain, both the right front and left rear hydraulic cylinders 12 and 13 perform substantially the same operation (compression operation), and Since both the left front hydraulic cylinders 11 and 14 and the right rear hydraulic cylinders 11 and 14 perform substantially the same operation (extension operation), the control cylinders are connected from the ports 12a and 13a of the both suspension hydraulic cylinders 12 and 13 through the pipes P2 and P3. 22, 23, 32, 33 and 42, 43 are supplied with substantially the same hydraulic pressure (the same neutral hydraulic pressure as shown in FIG. 1), and pipes P <b> 1 from the control cylinders 21, 24, 31, 34 and 41, 44. , P4, substantially the same hydraulic pressure (neutral hydraulic pressure) is supplied to the ports 11a, 14a of the suspension hydraulic cylinders 11, 14.

  In this state, the hydraulic pressures are balanced in the control cylinders 31, 34, 32, 33 and 41, 44, 42, 43 of the rolling suppressor 30 and the pitching suppressor 40, and the pistons 31a, 34a, 32a. 33a and 41a, 44a, 42a, 43a do not operate. On the other hand, in the bouncing suppressor 20, hydraulic oil is supplied to the control cylinders 22 and 23, and hydraulic oil is discharged from the control cylinders 21 and 24, so that the pistons 21a and 24a and 22a and 23a are in the same direction. Although it operates, since the operation amount is substantially equal, the bouncing suppressor 20 does not substantially function (does not suppress the operation of each suspension hydraulic cylinder 11, 12, 13, 14).

  As is apparent from the above description, in the vehicle suspension device of the first embodiment, the operation of each of the suspension hydraulic cylinders 11, 12, 13, 14 is performed by accumulator 25 (spring element) and variable throttle 26 (damping). A bouncing suppressor 20 including an element), a rolling suppressor 30 including a coil spring 36 (spring element) and a shock absorber 37 (damping element), and a coil spring 46 (spring element) and a shock absorber 47 (damping element). The pitching suppressor 40 is configured to suppress independently, and the characteristics of each spring element and each damping element that specify the suppression function of each suppressor 20, 30, 40 can be set independently. . Therefore, characteristics suitable for each behavior (bouncing, rolling, pitching) of the vehicle body can be set independently, and each behavior can be optimally suppressed.

  Further, in the vehicle suspension device of the first embodiment, the single ports 11a to 14a of the suspension hydraulic cylinders 11 to 14 attached to the front, rear, left and right wheels are connected by pipes P1 to P4. Thus, the hydraulic circuit can be configured, and the hydraulic circuit can be configured simply and inexpensively.

  Further, in the vehicle suspension device of the first embodiment, since the rolling suppressor 30 and the pitching suppressor 40 are provided in addition to the bouncing suppressor 20, the behavior of the vehicle body in the heave direction (bouncing) is effective. In addition, the behavior of the vehicle body in the roll direction (rolling) and the behavior in the pitch direction (pitching) can be effectively suppressed.

  In the vehicle suspension device of the first embodiment, an actuator capable of increasing / decreasing the hydraulic pressure of the hydraulic chamber 25 in the bouncing suppressor 20 is provided, or the spring force of the coil spring 36 in the rolling suppressor 30 can be increased / decreased controlled. Active actuator (see the phantom line in FIG. 2), or by providing an actuator (see the phantom line in FIG. 2) that can control the spring force of the coil spring 46 in the pitching suppressor 40 (see the phantom line in FIG. 2). It is possible to control.

  In the first embodiment described above, the vehicle ground load control device according to the present invention includes the ground load changing device 50 as shown in FIGS. 1 and 2, and the actuator 58 in the ground load changing device 50 is provided. Although implemented as a configuration including a hydraulic control device 60 for controlling the operation under the control of the electric control unit ECU, as in the second embodiment shown in FIGS. 18 and 19, the vehicle ground load control device according to the present invention is used. However, the hydraulic pressure from one of the ground load control hydraulic cylinders 81 operated by the differential pressure upon receiving the hydraulic pressure from the suspension hydraulic cylinders 11 and 12 for the left and right front wheels and the hydraulic pressure from the suspension hydraulic cylinders 13 and 14 for the left and right rear wheels. And the other contact load control hydraulic cylinders 82 operated by the differential pressure and the piston rods 8 of the contact load control hydraulic cylinders 81 and 82. The ratio of the axial force acting on b and 82b can be changed by changing the fulcrum position of the arm 83 connected to both piston rods 81b and 82b. It is also possible to implement as a configuration including a ground load changing device 80 including an actuator 85 that can be changed under the control of the control device ECU.

  One grounding load control hydraulic cylinder 81 is divided into two oil chambers by a piston 81a that is slidable in the axial direction. These oil chambers are connected to the ports 11a, 11 of the suspension hydraulic cylinders 11 and 12, respectively. 12a is connected to each other via pipes P1 and P2. The piston rod 81b integrated with the piston 81a extends outside the cylinder and is slidably connected along one elongated hole 83a at one end of the arm 83.

  The other contact load control hydraulic cylinder 82 is divided into two oil chambers by a piston 82a slidable in the axial direction. These oil chambers are connected to the ports 13a, 13 of the suspension hydraulic cylinders 13, 14, respectively. 14a is connected to each other via pipes P3 and P4. The piston rod 82b integrated with the piston 82a extends outside the cylinder, and one end of the piston rod 82b is rotatably connected to the other end of the arm 83. The other end of the piston rod 82b is connected to the rod 86a of the lock cylinder 86.

  The variable axial force ratio mechanism 84 includes a moving base 84a movable along the longitudinal direction of the arm 83, a connecting shaft 84b assembled at an intermediate portion of the moving base 84a, and a nut portion provided on the connecting shaft 84b ( The screw shaft 84c is screwed and connected to (not shown). The moving base 84 a is movably assembled in a guide hole 84 d provided in the fixed portion, and is slidably connected along the other long hole 83 b of the arm 83.

  The actuator 85 is an electric motor that changes the fulcrum position of the arm 83 by rotating the screw shaft 84c of the axial force ratio variable mechanism 84 and moving the moving base 84a along the guide hole 84d. The (rotation direction / number of rotations) is controlled by the electric control unit ECU 2 shown in FIG. 18, and a drive signal from the electric control unit ECU 2 is given via the drive circuit 71.

  The lock cylinder 86 is for restricting / permitting movement of the piston rod 82b in the axial direction, and the oil chamber defined by the piston 86b is communicated / blocked through the 2-port 2-position open / close valve 87. Yes. The two-port two-position opening / closing valve 87 is controlled to be opened / closed by the electric control unit ECU2 via the drive circuit 71, and allows the piston rod 82b to move in the axial direction in the open state and the piston in the closed state. The movement of the rod 82b in the axial direction is restricted.

  The electric control unit ECU2 is electrically connected to the hydraulic pressure sensors PS1 to PS4 and the drive circuit 71, and includes a motor current sensor S1, a steering angle sensor S2, a vehicle speed sensor S3, each wheel brake hydraulic pressure sensor S5, and each wheel speed sensor. It is electrically connected to S6, yaw rate sensor S7, lateral acceleration sensor S8, and the like.

  The electric control unit ECU2 includes a microcomputer having a CPU, a ROM, a RAM, an interface, and the like, and the CPU of the electric control unit ECU2 is illustrated when an ignition switch (not shown) is turned on. The control program corresponding to the flowchart of 20 is repeatedly executed every predetermined calculation cycle (for example, 8 msec) to control the operation of the actuator 85 and the 2-port 2-position opening / closing valve 87.

  The electric control unit ECU2 outputs a VSC control signal during VSC control of a known VSC device (vehicle stability control device) that suppresses understeer and oversteer when the vehicle turns. The electric control unit ECU2 is configured to be able to control the operation of a known steering gear ratio variable mechanism (VGRS) that varies the steering gear ratio in accordance with the vehicle speed.

  In the vehicle suspension apparatus of the second embodiment configured as described above, when the ignition switch is in the ON state, the CPU of the electric control unit ECU2 operates the actuator 85 based on the signal from each sensor. To control the ground contact load of the front, rear, left and right wheels FL, FR, RL, RR.

  The control of the ground load is performed by the CPU of the electric control unit ECU2 repeatedly executing the main routine shown in FIG. 20 every predetermined calculation cycle (for example, 8 msec). The process is started in step 101A of 20, the control presence / absence determination / initialization process is executed in step 200A, the VSC cooperative control process is executed in step 400A, and the vehicle speed response / VGRS cooperation / control speed is executed in step 600A. A limit process is executed, a yaw rate control process is executed in step 700A, a target fulcrum position calculation process is executed in step 800A, a motor control process is executed in step 900A, and the process is temporarily terminated in step 102A. .

  When the CPU of the electric control unit ECU2 executes the control presence / absence determination / initialization process in step 200A of FIG. 20, the subroutine shown in FIG. 21 is executed. Specifically, the CPU of the electric control unit ECU2 starts processing at step 251, sets the flag F to “0” at step 252, and sets the electric resistance value R of the actuator 85 (electric motor) at step 253. Is measured and memorized. This electrical resistance value R is measured from the detection signal of the motor current sensor S1 by passing a minute current through the actuator 85, and is larger than the set value Ro when the actuator 85 is disconnected and cannot be energized.

  For this reason, when the actuator 85 is disconnected (at the time of failure), the CPU of the electric control unit ECU2 determines “Yes” at step 254, and the 2-port 2-position opening / closing valve 87 is turned on at step 255. After outputting the closing signal for making the closing state to the drive circuit 71, the process returns to step 102A in FIG. 20, and the process is temporarily ended in step 102A. Therefore, when the actuator 85 is disconnected and the operation of the actuator 85 cannot be controlled, the lock cylinder 86 is hydraulically locked by the 2-port 2-position opening / closing valve 87, and the operation of the ground load changing device 80 is disabled. Is done. On the other hand, when the actuator 85 is not disconnected, the CPU of the electric control unit ECU2 determines “No” in step 254, executes step 256, and returns to the main routine of FIG.

  When the CPU of the electric control unit ECU2 executes the target fulcrum position calculation process in step 800A of FIG. 20, the subroutine shown in FIG. 22 is executed. Specifically, the CPU of the electric control unit ECU2 starts processing in step 851, confirms the flag F in step 852, and when the flag F is “0”, executes step 853 and then executes step 854. To return to the main routine of FIG. In step 853, the rear wheel cylinder side end position (position in FIG. 24B) of the moving base 84a is set to the zero point, and the front wheel cylinder side end position (position in FIG. 24C) is set to 100. The target fulcrum position is calculated and set based on the arithmetic expression from the length between them (full stroke) and the target roll rigidity front wheel distribution amount.

  Further, when the flag F is “1”, the lateral acceleration is leftward, and the target ground load on the left rear wheel is zero, Steps 855, 856, 857, and 858 are executed, and then Step 854 is executed. Return to the routine. Further, when the flag F is “1”, the lateral acceleration is leftward, and the target ground contact load of the left rear wheel is not zero, Steps 855, 856, 857, and 859 are executed, then Step 854 is executed, and the main routine of FIG. Return to.

  Further, when the flag F is “1”, the lateral acceleration is rightward, and the target ground load on the left rear wheel is zero, Steps 855, 856, 860, and 859 are executed, and then Step 854 is executed. Return to the routine. Further, when the flag F is “1”, the lateral acceleration is rightward, and the target ground load on the left rear wheel is not zero, Steps 855, 856, 860, 861 are executed, then Step 854 is executed, and the main routine of FIG. Return to.

  When the CPU of the electric control unit ECU2 executes the motor control process in step 900A of FIG. 20, the subroutine shown in FIG. 23 is executed. Specifically, the CPU of the electric control unit ECU2 starts processing at step 951, executes steps 952, 953, 954, 955, then executes step 956, and returns to the main routine of FIG.

  When the CPU of the electric control unit ECU2 executes the VSC cooperative control process in step 400A of FIG. 20, a subroutine that is substantially the same as the subroutine shown in FIG. 6 of the first embodiment is executed. Further, when the CPU of the electric control unit ECU2 executes the process in step 600A of FIG. 20, the substantially same subroutine as the subroutine shown in FIG. 9 of the first embodiment is executed. Further, when the CPU of the electric control unit ECU2 executes the yaw rate control process in step 700A of FIG. 20, the substantially same subroutine as the subroutine shown in FIG. 11 of the first embodiment is executed. For this reason, the description of the subroutine executed in each step 400A, 600A, 700A of FIG. 20 is omitted.

  As is apparent from the above description, in the vehicle suspension device of the second embodiment, for example, a front wheel skid occurs during VSC control during a left turn, and the brake hydraulic pressure of the right front wheel FR is greater than the threshold value 4. When the brake hydraulic pressure of the left rear wheel RL is greater than the threshold value 5 and the brake hydraulic pressure of the right rear wheel RR is less than or equal to the threshold value 5, the steps 402, 403, and 405 in FIG. , 406, 410, 411, 408, 409 are executed, steps 852, 855, 856, 857, and 858 are executed in the subroutine of FIG. 22, and all steps are executed in the subroutine of FIG. The actuator (electric motor) 85 is energized according to the drive pulse pattern obtained by the calculation in step 954. It is driven Te.

  Therefore, at this time, the moving base 84a of the ground load changing device 80 is pressed toward the state shown in FIG. 24B by the actuator 85, and the ground load is moved to the left front wheel FL and the right rear wheel RR. it can. Therefore, the roll stiffness distribution is later and the tendency toward oversteering can be reduced, so that the amount of side slip of the front wheels can be reduced. In FIG. 24, the size of each ground load is indicated by a circle in accordance with each wheel FL, FR, RL, RR.

  When the rear wheel side slip occurs during the VSC control during the left turn, the brake hydraulic pressure of the right front wheel FR is larger than the threshold value 4, and the brake hydraulic pressure of the left rear wheel RL becomes the threshold value 5 or less, the subroutine of FIG. Steps 402, 403, 405, 406, 410, 412, and 413 in FIG. 6 are executed in the subroutine similar to FIG. 22, steps 852, 855, 856, 857, and 859 are executed in the subroutine in FIG. All the steps are executed in the subroutine, and the actuator (electric motor) 85 is energized and driven according to the drive pulse pattern obtained by the calculation of step 954.

  Therefore, at this time, the moving base 84a of the ground load changing device 80 is pressed toward the state of FIG. 24C by the actuator 85, and the ground load can be moved to the right front wheel FR and the left rear wheel RL. it can. Therefore, the braking force of the right front wheel FR is increased, and the side slip amount of the rear wheel can be reduced.

  The other specific operations and effects obtained by the second embodiment are described as the specific operations and effects of the first embodiment and the specific operations and effects of the second embodiment. The explanation is omitted because it seems to be easily understood from the contents.

  In each of the above embodiments, the present invention is implemented as a configuration including the bouncing suppressor 20, the rolling suppressor 30, and the pitching suppressor 40. However, as shown in FIG. 25, the bouncing suppressor 20, the rolling suppressor 30, and It is also possible to employ a configuration in which the pitching suppressor 40 is not provided, and the suspension hydraulic cylinders 11, 12, 13, and 14 are each provided with an accumulator 90 and a damping valve 91.

  In each of the above embodiments, the suspension hydraulic cylinders 11, 12, 13, and 14 all share the ground loads of the front and rear wheels FL, FR, RL, and RR. Although the present invention has been implemented, auxiliary springs are provided in parallel to the suspension hydraulic cylinders 11, 12, 13, and 14, respectively, and the suspension hydraulic cylinders 11, 12, 13, and 14 are connected to the auxiliary cylinders. Embodiment in which the ground load of each of the front, rear, left and right wheels FL, FR, RL, RR is shared by a spring (each auxiliary spring uses a part of the ground load of each wheel FL, FR, RL, RR) It is also possible to implement the present invention in the respective embodiments).

  Further, when the control program is set so that the operation of the hydraulic cylinder for ground load control is disabled when the vibration input from the road surface is excessive when the present invention is carried out, the required output of the actuator is reduced, and the actuator It is possible to reduce the energy consumption of the physique and actuator.

1 is a configuration diagram schematically illustrating a first embodiment of a vehicle suspension device including a vehicle ground load control device according to the present invention. FIG. FIG. 2 is an enlarged view of the mechanical system configuration shown in FIG. 1. It is a flowchart which shows the main routine which CPU of the electric control apparatus shown in FIG. 1 performs. It is a flowchart which shows the subroutine performed at step 200 of FIG. It is a flowchart which shows the subroutine performed in step 300 of FIG. It is a flowchart which shows the subroutine performed at step 400 of FIG. It is a flowchart which shows the subroutine performed in step 500 of FIG. It is a map which shows the relationship between a slip ratio, a contact load, and road surface μ. It is a flowchart which shows the subroutine performed in step 600 of FIG. It is a map which shows the relationship between a vehicle speed, a gear ratio, and roll rigidity distribution (front wheel). It is a flowchart which shows the subroutine performed in step 700 of FIG. It is a map which shows the relationship between the deviation of a yaw rate, and roll rigidity distribution (front wheel). It is a flowchart which shows the subroutine performed in step 800 of FIG. It is a flowchart which shows the subroutine performed in step 900 of FIG. FIG. 6 is an operation explanatory diagram when the ground load is controlled in a straight traveling state of the vehicle in the first embodiment. FIG. 6 is an operation explanatory diagram when the ground load is controlled in the right turn state of the vehicle in the first embodiment. FIG. 5 is an operation explanatory diagram when the ground load is controlled in the left turn state of the vehicle in the first embodiment. It is the block diagram which showed schematically 2nd Embodiment of the suspension apparatus for vehicles containing the vehicle ground load control apparatus by this invention. It is an enlarged view of the mechanical system structure shown in FIG. It is a flowchart which shows the main routine which CPU of the electric control apparatus shown in FIG. 18 performs. It is a flowchart which shows the subroutine performed by step 200A of FIG. It is a flowchart which shows the subroutine performed at step 800A of FIG. It is a flowchart which shows the subroutine performed in step 900A of FIG. FIG. 12 is an operation explanatory diagram when the ground load is controlled in the left turn state of the vehicle in the second embodiment. It is the block diagram which showed schematically the deformation | transformation embodiment of the mechanical system structure in the vehicle ground load control apparatus by this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11, 12, 13, 14 ... Hydraulic cylinder for suspension, 11a, 12a, 13a, 14a ... Port, 20 ... Bouncing suppressor, 26 ... Accumulator, 27 ... Variable throttle (damping valve), 30 ... Rolling suppressor, 40 ... Pitching suppressor, 50 ... Grounding load changing device, 50A, 50B ... Grounding load control cylinder, 58 ... Actuator, 60 ... Hydraulic control device, 61 ... Pump, 62 ... Electric motor, 63 ... 4-port 2-position switching valve, 64 ... 2-port 2-position open / close valve, P1, P2, P3, P4 ... piping, S1 ... motor current sensor, S2 ... steering angle sensor, S3 ... vehicle speed sensor, S4 ... tire pressure sensor for each wheel, S5 ... brake oil pressure sensor for each wheel, S6: Each wheel speed sensor, S7: Yaw rate sensor, S8: Lateral acceleration sensor, PS1 to PS6 ... Hydraulic pressure sensor, ECU ... Electric The control device.

Claims (1)

Front / rear / left / right load sharing means for sharing the ground load of each front / rear / right / left wheel, load changing means for changing the ground load shared by each load sharing means by operation, and vehicle state detection for detecting the vehicle state In the vehicle ground load control device comprising: a control means for controlling the operation of the load changing means in accordance with a detection signal from the vehicle state detecting means; The operation to change each grounding load of the diagonal wheel and each grounding load of the other pair of diagonal wheels in opposite increasing / decreasing directions, and changing each grounding load in each diagonal wheel in the same increasing / decreasing direction Load changing means is adopted, and the front / rear / left / right load sharing means that share the ground contact load of the front / rear / right / left wheels are respectively attached to the front / rear / right / left wheels, and a single port is installed. Load changing means that can change the grounding load shared by each of the suspension hydraulic cylinders by operating each of the suspension hydraulic cylinders attached to the left and right front wheels. One grounding load control hydraulic cylinder which receives hydraulic pressure and operates by differential pressure, and the other grounding load control which operates by differential pressure by receiving hydraulic pressure from each of the suspension hydraulic cylinders mounted corresponding to the left and right rear wheels Axial force ratio variable mechanism that can change the ratio of the axial force acting on each piston rod of the hydraulic cylinder for grounding load control and the hydraulic cylinder for ground contact load control by changing the fulcrum position of the arm connected to both piston rods And an actuator capable of changing the fulcrum position of the arm in accordance with a detection signal from the vehicle state detection means. The vehicle ground contact load control device that.

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