JP2019051810A - Vehicle brake control device, vehicle brake control method and vehicle brake system - Google Patents

Abstract

To provide a vehicle brake control device that can provide a preferable braking state in accordance with a degree of deceleration that is required for a vehicle.SOLUTION: A vehicle brake control device includes: an input part to which information relating to a degree of deceleration that is required for a vehicle is input; and a control part capable of switching a difference between brake force imparted to a front wheel of the vehicle by operating a front brake device and brake force imparted to a rear wheel of the vehicle by operating a rear brake device, in accordance with the information relating to the degree of deceleration to be input.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a vehicle braking control device, a vehicle braking control method, or a vehicle braking system.

  2. Description of the Related Art Conventionally, there is known a vehicle braking control device that can apply a braking force to a front wheel of a vehicle by operating a front braking device, and can apply a braking force to a rear wheel of a vehicle by operating a rear braking device. Yes. For example, the vehicle braking control device disclosed in Patent Document 1 is configured such that, during a brake operation, the rear braking device applies braking force to the rear wheels before the front braking device applies braking force to the front wheels. . By applying a braking force to the rear wheels prior to the front wheels, the load movement of the vehicle toward the front wheels becomes gentle, and the pitching behavior of the vehicle during deceleration is reduced. As a result, discomfort to the occupant is reduced to improve ride comfort.

JP 2009-208518 A

  In the conventional technique described above, in a state where it is desired to obtain a high deceleration, the load movement to the front wheel side is delayed, so that it takes time to generate the deceleration of the vehicle, and the stopping distance may be increased.

  A vehicle braking control device according to an embodiment of the present invention provides a difference between a braking force applied to a front wheel by operating a front braking device and a braking force applied to a rear wheel by operating a rear braking device. It is possible to switch according to the information regarding the deceleration required for the vehicle.

  Thus, the braking state can be optimized according to the deceleration required for the vehicle.

1 shows a configuration of a braking system according to a first embodiment. 2 shows an overall flow of control executed by the control unit of the first embodiment. The threshold value used when the control part of 1st Embodiment determines a control mode is shown. An example of a time change in braking force in the first control of the first embodiment is shown. FIG. 6 shows another example of the time change of the braking force in the first control of the first embodiment. FIG. FIG. 6 shows another example of the time change of the braking force in the first control of the first embodiment. FIG. FIG. 6 shows another example of the time change of the braking force in the first control of the first embodiment. FIG. An example of the time change of the braking force in the second control of the first embodiment is shown. An example of the time change of the braking force in the third control of the first embodiment is shown. The pattern of the time change of target braking force is illustrated. An example of the time change of braking force when the target braking force is set based on the change gradient of the stroke amount of the brake pedal in the first embodiment will be shown. FIG. 6 shows another example of the time change of the braking force when the target braking force is set based on the change gradient of the stroke amount of the brake pedal in the first embodiment. The map used when the control part of 2nd Embodiment determines a control mode is shown. The map used when the control part of 3rd Embodiment determines a control mode is shown. The structure of the braking system of 4th Embodiment is shown. FIG. 10 shows a partial cross section of a wheel cylinder and an electric braking mechanism in a rear right wheel of a fourth embodiment. 10 shows a configuration of a braking system of a fifth embodiment. 10 shows a configuration of a braking system of a sixth embodiment.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

[First embodiment]
First, the configuration will be described. As shown in FIG. 1, the vehicle has front left wheel 2FL, front right wheel 2FR, rear left wheel 2RL, and rear right wheel 2RR as wheels. Each wheel has a brake disc and a brake pad. The vehicle braking system 1 includes a brake pedal 3, a front braking device 1F, a rear braking device 1R, and a control unit. The brake pedal 3 is an operation member to which a brake operation of a vehicle driver is input. The braking system 1 is a so-called by-wire system, and the braking force of each wheel can be arbitrarily controlled by the front braking device 1F and the rear braking device 1R having different energy sources.

  The front braking device 1F includes a hydraulic braking mechanism that generates braking force using the pressure (hydraulic pressure) of the brake fluid, and can apply braking force to the front left wheel 2FL and the front right wheel 2FR. The front braking device 1F includes a reservoir tank 4, a master cylinder 5, a hydraulic pressure control unit 6, a wheel cylinder 19, and a stroke simulator 66. The reservoir tank 4 stores brake fluid. A brake pipe 10I is connected to the reservoir tank 4. The master cylinder 5 is connected to the brake pedal 3 via the push rod 30. The master cylinder 5 is a tandem type and has two hydraulic chambers that are independent of each other. Brake pipes 10P and 10S are connected to the respective hydraulic pressure chambers. A hydraulic pressure (master cylinder hydraulic pressure) is generated in each hydraulic pressure chamber in response to the depression of the brake pedal 3. A reservoir tank 4 is installed in the master cylinder 5. Brake fluid is replenished from the reservoir tank 4 to each hydraulic pressure chamber.

  The fluid pressure control unit 6 includes a fluid pressure circuit formed of a plurality of fluid passages formed inside the housing, a solenoid valve 61 that can switch between fluid passage and passage, and a fluid pressure different from that of the master cylinder 5. And a pump unit 60 as a source. The fluid pressure control unit 6 generates fluid pressure in the fluid pressure circuit by the pump unit 60 (first energy source) and controls the opening and closing of the solenoid valve 61 and the like to control any fluid regardless of the brake operation. Pressure (control hydraulic pressure) can be supplied to the outside. Brake pipes 10FL and 10FR are connected to the hydraulic pressure control unit 6. Brake fluid can be supplied from the reservoir tank 4 to the pump unit 60 via the brake pipe 10I. A brake pipe 10FL is connected to the wheel cylinder 19FL of the front left wheel 2FL, and a brake pipe 10FR is connected to the wheel cylinder 19FR of the front right wheel 2FR. The wheel cylinder 19 is a caliper having a cylinder and a piston. Looking at the wheel cylinder 19FL, the hydraulic pressure supplied from the brake pipe 10FL to the cylinder propels the piston. When the piston presses the brake pad against the disc rotor, braking force is applied to the front left wheel 2FL. The piston functions as a braking member. The same applies to the wheel cylinder 19FR. The hydraulic pressure control unit 6 is supplied with brake fluid (master cylinder hydraulic pressure) from each hydraulic pressure chamber of the master cylinder via the brake pipes 10P and 10S, and the brake fluid (master cylinder) via the brake pipes 10FL and 10FR. Cylinder hydraulic pressure) can be supplied to the wheel cylinders 19FL and 19FR. Further, the hydraulic pressure control unit 6 can supply brake fluid (control hydraulic pressure) to the wheel cylinders 19FL, 19FR via the brake pipes 10FL, 10FR. The hydraulic control unit 6 and the wheel cylinders 19FL and 19FR function as a hydraulic braking mechanism. The stroke simulator 66 operates by receiving brake fluid flowing out from the master cylinder 5 in a state where the communication between the master cylinder 5 and the wheel cylinder 19 is blocked by the fluid pressure control unit 6. In the stroke simulator 66, the spring is compressed in accordance with the operation of the piston, so that a pseudo reaction force (simulating a state where the master cylinder 5 and the wheel cylinder 19 communicate with each other) can be applied to the brake pedal 3.

  The rear braking device 1R includes electric braking mechanisms 7RL and 7RR that generate braking force using the power of the electric motor (motor: second energy source), and can apply braking force to the rear left wheel 2RL and the rear right wheel 2RR. is there. The electric braking mechanism 7RL is disposed on the rear left wheel 2RL, and includes a motor, a rotation-linear motion conversion mechanism, a caliper, and a sub control unit (sub CU). The sub CU supplies power to the motor in accordance with a command signal input via the communication line 90, and drives the motor. The rotation-linear motion conversion mechanism includes a ball screw mechanism and the like, and decelerates the rotation of the output shaft of the motor and converts it into linear motion to propel the caliper piston. When the piston presses the brake pad against the brake disc (disc rotor), braking force is applied to the rear left wheel 2RL. The piston functions as a braking member. Inside the electric braking mechanism 7RL, a thrust sensor for detecting the linear motion thrust of the piston is installed. The thrust sensor is used to control the linear motion thrust of the piston to a target value. The same applies to the electric braking mechanism 7RR.

  The control unit is a vehicle braking control device. The control unit includes a front control unit (front CU) 9F and a rear control unit (rear CU) 9R. The front CU9F mainly controls the braking force of the front wheels 2FL and 2FR, and the rear CU9R mainly controls the braking force of the rear wheels 2RL and 2RR. The front CU 9F is connected to each actuator of the hydraulic pressure control unit 6 and can control these operations. The front CU is installed in the hydraulic control unit 6 (integrated with the hydraulic control unit 6), but is separate from the hydraulic control unit 6 and is connected to the hydraulic control unit 6 via a communication line. It may be configured. The rear CU9R is connected to the sub CUs of the electric braking mechanisms 7RL and 7RR via a communication line, and can control the operation of the motor. Both units 9F and 9R are connected via a communication line 90, and can exchange signals with each other. Both units 9F and 9R are connected to an external recognition device 80, a stroke sensor 81, and other control units of the vehicle via communication lines, and can receive signals from these. The external recognition device 80 is a device capable of recognizing an object (such as a preceding vehicle or an obstacle) in the outside of the vehicle including the traveling direction (forward) of the vehicle. For example, a camera, a rider, a millimeter wave radar, and the like.

  The hydraulic control unit 6 will be described in detail. The hydraulic circuit is divided into a primary P system and a secondary S system. Hereinafter, in order to indicate which member or configuration corresponds to each system, P and S are added to the reference numerals for distinction. Further, in order to indicate which of the front left wheel 2FL and the front right wheel 2FR corresponds to the member or the configuration, the reference numerals are assigned with FL and FR. Multiple solenoid valves include shut-off valve 61, pressure increasing valve 62, communication valve 63, pressure regulating valve 64, pressure reducing valve 65, simulator-in valve (SS-IN valve) 67, and simulator-out valve (SS-OUT valve) 68 Have The shut-off valve 61, the pressure increasing valve 62, and the pressure regulating valve 64 are normally open valves that are opened in a non-energized state. The communication valve 63, the pressure reducing valve 65, the SS-IN valve 67, and the SS-OUT valve 68 are normally closed valves that close in a non-energized state. The shut-off valve 61, the pressure increasing valve 62, and the pressure regulating valve 64 are proportional control valves in which the opening degrees of the valves are adjusted according to the current supplied to the solenoid. The communication valve 63, the pressure reducing valve 65, the SS-IN valve 67, and the SS-OUT valve 68 are on / off valves that are controlled to be switched in a binary manner. The pump unit 60 includes a motor 600 and a pump 601. The motor 600 may be a brushed motor or a brushless motor having a resolver. Pump 601 is driven by motor 600. The pump 601 is commonly used in the P system and the S system. The pump 601 is a plunger pump and includes a plurality of (for example, five) cylinders (plungers). The pump 601 may be a gear pump or the like.

  The plurality of liquid paths are the supply liquid path 11, the suction liquid path 12, the discharge liquid path 13, the communication liquid paths 13P and 13S, the pressure adjustment liquid path 14, the decompression liquid path 15, the simulator liquid path 16, and the back pressure supply liquid path 17. , And a back pressure drainage channel 18. One end of the supply liquid path 11P is connected to the brake pipe 10P, and the other end is connected to the brake pipe 10FL as a liquid path 11FL. The supply liquid path 11P has a shutoff valve 61P. There is a pressure increasing valve 62FL between the shutoff valve 61P and the brake pipe 10FL (liquid path 11FL) in the supply liquid path 11P. The same applies to the supply liquid passage 11S. One end of the suction liquid passage 12 is connected to the brake pipe 10I via a liquid reservoir chamber (volume chamber). The other end of the suction fluid path 12 is connected to the suction port of the pump 601. One end of the discharge liquid path 13 is connected to the discharge port of the pump 601. The discharge liquid path 13 branches into a liquid path 13P and a liquid path 13S. The branch liquid path 13P is connected between the cutoff valve 61P and the pressure increasing valve 62P in the supply liquid path 11P. The same applies to the branch liquid passage 13S. The branch liquid paths 13P and 13S are connected to each other and function as a communication liquid path. The fluid passages 13P and 13S each have a communication valve 63. One end of the pressure adjusting fluid passage 14 is connected between the communication valves 63P and 63S (the discharge side of the pump 601) in the communication fluid passages 13P and 13S. The other end of the pressure adjusting liquid passage 14 is connected to the brake pipe 10I through the liquid reservoir chamber. A pressure regulating valve 64 is provided in the pressure regulating fluid path 14. One end of the decompression liquid path 15FL is connected between the pressure increasing valve 62FL and the brake pipe 10FL in the supply liquid path 11FL. The other end of the decompression liquid path 15FL is connected to the brake pipe 10I through the liquid reservoir chamber. A pressure reducing valve 65FL is provided in the pressure reducing liquid passage 15FL. The same applies to the decompression liquid passage 15FR. One end of the simulator liquid path 16 is connected between the brake pipe 10P and the shutoff valve 61P in the supply liquid path 11P. The other end of the simulator liquid path 16 is connected to the positive pressure chamber of the stroke simulator 66. The stroke simulator 66 is installed in the hydraulic pressure control unit 6, but is not limited thereto. One end of the back pressure supply liquid path 17 is connected to the back pressure chamber of the stroke simulator 66. The other end of the back pressure supply liquid path 17 is connected between the shutoff valve 61S and the pressure increasing valve 62FR in the supply liquid path 11S (liquid path 11FR). The back pressure supply fluid path 17 has an SS-IN valve 67. A check valve 670 is provided in a liquid path that is in parallel with the back pressure supply liquid path 17 and bypasses the SS-IN valve 67. The valve 670 allows only the flow of brake fluid from the back pressure chamber side to the supply fluid path 11FR side. One end of the back pressure discharge liquid path 18 is connected between the back pressure chamber and the SS-IN valve 67 in the back pressure supply liquid path 17. The other end of the back pressure discharge liquid path 18 is connected to the brake pipe 10I through the liquid reservoir chamber.

  Between the brake pipe 10P and the shutoff valve 61P in the supply fluid path 11P, there is a fluid pressure sensor 82 that detects the fluid pressure (master cylinder fluid pressure) at this location. Between the shutoff valve 61P and the pressure increasing valve 62FL in the supply liquid path 11P, there is a hydraulic pressure sensor 83P that detects the hydraulic pressure at this location (corresponding to the hydraulic pressure of the wheel cylinder 19FL). The S system has a similar hydraulic pressure sensor 83S.

  The hydraulic pressure control unit 6 drives the motor 600 at a predetermined rotation speed (ie, pumps) with the shut-off valve 61 closed, the communication valve 63 opened, and the simulator out valve 68 opened, for example. A predetermined amount of brake fluid is discharged from 601), and the valve opening amount of the pressure regulating valve 64 is controlled. As a result, it is possible to realize the desired hydraulic pressure of the wheel cylinders 19FL and 19FR while operating the stroke simulator 66 to generate a brake operation reaction force. By closing the pressure increasing valve 62 and opening the pressure reducing valve 65 as necessary, the hydraulic pressure in the wheel cylinders 19FL and 19FR can be maintained and reduced separately. The hydraulic pressure sensor 83 is used to control the hydraulic pressure of the wheel cylinders 19FL and 19FR to a target value.

  The control unit will be described in detail. For example, the control unit has a central processing unit (CPU), a read only memory (ROM), a random access memory (RAM), and an input / output port device, and these are connected to each other by a bidirectional common bus. It may be a microcomputer. The control unit receives inputs such as detection values sent from the stroke sensor 81 and other sensors, information on the running state sent from the vehicle side, command signals sent from an external control unit, etc. Control can be performed. Brake control includes anti-lock brake control (ABS) to suppress slippage of wheel 2 due to braking, as well as each wheel 2FL to 2RR to realize functions to prevent vehicle side-slip and automatic brake control. Includes braking force control. Automatic brake control includes tracking to the preceding vehicle (the former tracking) or maintaining control of the inter-vehicle distance (automatic inter-vehicle control), emergency avoidance control for collisions with obstacles, and avoidance control for lane departure (lane departure prevention support) Etc. Specifically, the control unit receives the above input, determines whether to intervene and disengage the brake control, calculates the target braking force of each wheel 2FL to 2RR, and calculates the hydraulic pressure control unit 6 and / or electric braking. Command signals are output to mechanisms 7RL and 7RR. Each actuator is driven to control the braking force of each wheel 2FL to 2RR to be the target braking force.

  The front CU 9F includes an input unit 91F and a control unit 92F. Signals from the stroke sensor 81, the external recognition device 80, and other control units of the vehicle are input to the input unit 91F. Of these signals, the signal acquired by the stroke sensor 81 is the stroke amount of the brake pedal 3, and is information relating to the driver's brake operation. The signal acquired by the external recognition device 80 is information related to the outside world of the vehicle (preceding vehicle, obstacle, etc.). The signal from the other control unit is, for example, a signal (automatic brake command signal) for instructing execution of automatic brake control. Note that the input unit 91F may receive the detection signal of the external recognition device 80 via another control unit. The deceleration required by the driver for the vehicle (the driver's intention to brake) is reflected in the depression amount (stroke amount) of the brake pedal 3. Therefore, the signal acquired by the stroke sensor 81 can be used as information regarding the deceleration required for the vehicle (requested deceleration). The target for measuring the stroke amount is not limited to the brake pedal 3, but may be the push rod 30 or the piston of the master cylinder 5. Further, the required deceleration is also reflected in the force applied to the brake pedal 3. Therefore, in order to detect the required deceleration, in addition to the stroke, the force that depresses the brake pedal 3 (pedal depression force), the load that acts on the push rod 30 that pushes the piston of the master cylinder 5, and the generated master cylinder hydraulic pressure are measured. May be. In automatic brake control, the vehicle deceleration required for following the preceding vehicle and avoiding collisions with obstacles depends on the speed of the vehicle relative to the preceding vehicle (relative speed), the distance from the vehicle to the obstacle, etc. Determined. Therefore, the signal acquired by the external recognition device 80 can be used as information related to the deceleration required for the vehicle (requested deceleration).

  The control unit 92F calculates a target braking force (target braking force) using the detection value of the stroke sensor 81 among the information input to the input unit 91F. During automatic brake control, the target braking force is calculated based on the detection signal of the external recognition device 80. Since the target braking force is a value representing the required deceleration, this is hereinafter referred to as G. The control unit 92F executes the braking control by outputting a command signal for realizing the target braking force G to the hydraulic pressure control unit 6 and / or the rear CU 9R (via the electric braking mechanisms 7RL and 7RR). . The target of the braking force applied to the front wheels 2FL and 2FR corresponds to (converted to) the hydraulic pressure target of the wheel cylinders 19FL and 19FR to be realized by the hydraulic pressure control unit 6. The target of the braking force applied to the rear wheels 2RL and 2RR corresponds to the target of the force with which the motor propels the piston in the electric braking mechanisms 7RL and 7RR (converted). The braking control has a plurality of control modes. The control mode includes a first control, a second control, and a third control. The control unit 92F determines which of the first to third controls is to be executed according to the magnitude of the target braking force G.

  The braking force applied to the front wheels 2FL and 2FR by operating the hydraulic pressure control unit 6 is defined as g (F). The braking force applied to the rear wheels 2RL and 2RR by operating the electric braking mechanisms 7RL and 7RR is defined as g (R). The first control is a mode in which g (R) is substantially larger than g (F). For this purpose, for example, the hydraulic control unit 6 is operated after the electric braking mechanisms 7RL and 7RR are operated. The second control is a mode in which g (F) and g (R) are set to substantially the same size. For this purpose, for example, the hydraulic control unit 6 is operated and the electric braking mechanisms 7RL and 7RR are operated (the unit 6 and the mechanism 7 are operated substantially simultaneously). The third control is a mode in which g (F) is substantially larger than g (R). Therefore, for example, after the hydraulic pressure control unit 6 is operated, the electric braking mechanisms 7RL and 7RR are operated or only the hydraulic pressure control unit 6 is operated (the electric braking mechanisms 7RL and 7RR are not operated). The term “substantially” means that at least at the beginning of control. By switching the control mode between the first to third controls, the difference between g (F) and g (R) is switched.

  As shown in FIG. 2, the control unit 92F determines a control mode at a predetermined cycle, and executes braking control according to the selected control mode. Specifically, in step S1, control unit 92F determines whether or not there is a brake operation based on the detection value (stroke amount) of stroke sensor 81. If there is a brake operation, the process proceeds to step S2, and if not, the process proceeds to step S4. In step S2, a target braking force G is calculated based on the stroke amount. Thereafter, the process proceeds to step S3. For example, the target braking force G is increased as the stroke amount is increased. Note that the presence or absence of a brake operation may be determined based on the pedal depression force, the detected value of the master cylinder hydraulic pressure, or the like, and the target braking force G may be calculated. In step S3, it is determined whether there is an input of an automatic brake command signal or whether an obstacle is detected by the external recognition device 80. If there is an input of an automatic brake command signal or the like, it is determined that automatic brake control such as preceding vehicle tracking or emergency avoidance is executed, and the process proceeds to step S6, and if not, the process proceeds to step S8. In step S4, the same determination as in step S3 is performed. If there is an input of an automatic brake command signal, the process proceeds to step S5, and if not, the control is terminated. When the vehicle stops (the vehicle speed is substantially zero), an appropriate inter-vehicle distance is secured with the preceding vehicle, or there are no obstacles in the traveling direction due to lane changes, etc. To establish. In step S5, the target braking force G is calculated based on the detection signal of the external recognition device 80. Thereafter, the process proceeds to step S8. For example, when there is a command for preceding vehicle following control, the target braking force G is calculated from the relative speed with respect to the preceding vehicle. The target braking force G is increased as the relative speed increases, that is, as the speed of the host vehicle is higher than the speed of the preceding vehicle (an object in the traveling direction of the host vehicle) obtained from the detection signal. In step S6, the same calculation as in step S5 is performed, and the process proceeds to step S7. In step S7, the target braking force G calculated in step S2 is compared with the target braking force G calculated in step S6, and the larger value is adopted as the target braking force G actually used for control. Thereafter, the process proceeds to step S8. In step S8, a control mode is determined based on the target braking force G (calculated in step S5 or adopted in step S7). Thereafter, the process proceeds to step S9. In step S9, braking control is executed according to the control mode determined in step S8. Thereafter, the process returns to step S1. Specifically, the control unit 92F outputs a command signal for realizing the target braking force G to the hydraulic pressure control unit 6 and / or the rear CU 9R according to the determined control mode. Note that other brake controls may intervene as appropriate during execution of the brake control. For example, slip of the wheel 2 can be suppressed by the intervention of ABS.

  At step S8, the control unit 92F performs the first control when the target braking force G is less than the first threshold G1, as shown in FIG. The second control is performed when the target braking force G is greater than or equal to G1 and less than the second threshold G2. The third control is performed when the target braking force G is equal to or greater than G2. Assuming regions A1, A2, and A3 separated by lines L1 and L2 corresponding to thresholds G1 and G2, G being less than G1 means that G is in region A1. G being G1 or more and less than G2 means that G is in the region A2. G being equal to or greater than G2 means that G is in the region A3. The travel distance required as the lower limit until the host vehicle stops is hereinafter referred to as a required stop distance. The travel distance required as the upper limit until the host vehicle stops is hereinafter referred to as a required stop distance. The control unit 92F corrects the threshold values G1 and G2 according to the values related to these stop distances. When the necessary stop distance is long, the thresholds G1 and G2 are corrected to be smaller than when the required stop distance is short. When the required stop distance is short, the thresholds G1 and G2 are corrected so as to be smaller than when the required stop distance is long. For example, the required stop distance is long when the speed of the host vehicle (vehicle speed) is high. The required stopping distance is long when the friction coefficient (road surface μ) of the road surface with which the wheel 2 is in contact is small. When the distance (relative distance) between an object (obstacle) in the traveling direction of the host vehicle and the host vehicle is short, the required stop distance is short. Therefore, the control unit 92F corrects G1 and G2 to smaller values G1 ′ and G2 ′, respectively, when the vehicle speed is high than when the vehicle speed is low. In other words, when the vehicle speed is low, G1 and G2 are corrected to larger values G1 ″ and G2 ″ than when the vehicle speed is high. When the road surface μ is small, G1 and G2 are corrected to smaller values G1 ′ and G2 ′ than when the road surface μ is large. In other words, when the road surface μ is large, G1 and G2 are corrected to larger values G1 ″ and G2 ″ than when they are small. As the road surface μ, for example, a value estimated in the ABS control can be used. When the relative distance is short, G1 and G2 are corrected to smaller values G1 ′ and G2 ′ than when the relative distance is long. In other words, when the relative distance is long, G1 and G2 are corrected to larger values G1 ″ and G2 ″ than when the relative distance is short. The relative distance can be grasped using, for example, position information by GPS, a highly accurate map, or the like. When G1 and G2 are corrected in this way, the lines L1 and L2 corresponding to G1 and G2 are also corrected to L1 ′, L2 ′ and L1 ″ and L2 ″, respectively, and as a result, the regions A1 to A3 are corrected. Each increase or decrease.

  The rear CU9R includes an input unit 91R and a control unit 92R. The input unit 91R has the same configuration as the input unit 91F. The control unit 92R has the same configuration as the control unit 92F. The control unit 92R executes the braking control by outputting a command signal for realizing the target braking force G to the electric braking mechanisms 7RL, 7RR and / or the front CU 9F (via the hydraulic pressure control unit 6). . The control unit 92R calculates the target braking force G independently of the control unit 92F and determines the control mode. Note that one of the control unit 92F and the control unit 92R may calculate the target braking force G and determine the control mode, and may instruct the other. In other words, the control unit 92F and the control unit 92R may share the function of the control unit. In addition, the control unit (integrated control unit) that calculates the target braking force G and determines the control mode is separate from the control units 92F and 92R (CU9F and 9R), and has a configuration in which commands are issued to the CU9F and 9R. Good.

  Next, the function and effect will be described. Conventionally, in a vehicle braking control device that can apply a braking force to a front wheel of a vehicle by operating a front braking device and can apply a braking force to a rear wheel of a vehicle by operating a rear braking device, Sometimes, a vehicle braking control device is known in which a rear braking device applies a braking force to a rear wheel before a front braking device applies a braking force to a front wheel. By applying a braking force to the rear wheels prior to the front wheels, the load movement of the vehicle toward the front wheels becomes gentle, and the pitching behavior of the vehicle during deceleration is reduced. As a result, discomfort to the occupant is reduced to improve ride comfort. However, in a state where it is desired to obtain a high deceleration, the load movement to the front wheel side is delayed, so that it takes time to generate the deceleration and there is a possibility that the stopping distance becomes long. On the other hand, in the control unit of the present embodiment, the control unit 92 has a braking force applied to the front wheels 2FL, 2FR by operating the front braking device 1F, and a rear wheel 2RL, by operating the rear braking device 1R. The difference from the braking force applied to 2RR can be switched according to the information on the deceleration required for the vehicle (input from the input unit 91). Thus, the braking state can be optimized according to the deceleration required for the vehicle. For example, a plurality of braking states with different deceleration required for the vehicle are created, and between these braking states, the braking force of the front wheels 2FL and 2FR by the operation of the front braking device 1F and the rear braking device 1R by the operation If it is confirmed that the difference between the braking force of the wheels 2RL and 2RR is switched, the operation of the control unit of the present embodiment is estimated.

  When the deceleration required for the vehicle is low, the control unit 92 operates the front braking device 1F at least at the start of generation of braking force (including immediately after the start; the same applies hereinafter) than when it is high. The braking force applied to the front wheels 2FL and 2FR is made smaller than the braking force applied to the rear wheels 2RL and 2RR by operating the rear braking device 1R. Therefore, in a situation where the required deceleration is low, the rear side braking force becomes larger than the front side braking force at least at the start of braking force generation, so that the vehicle load fluctuation to the front wheels 2FL, 2FR side It becomes gentle and the pitching behavior of the vehicle is reduced, and the ride comfort is improved. In other words, the control unit 92 gives the front wheels 2FL and 2FR by operating the front braking device 1F at least at the start of generation of braking force when the deceleration required for the vehicle is high, rather than when it is low. The braking force is made larger than the braking force applied to the rear wheels 2RL and 2RR by operating the rear braking device 1R. Therefore, in a situation where the required deceleration is high, the vehicle load moves toward the front wheels 2FL and 2FR because the braking force on the front side becomes larger than the braking force on the rear side at least when the generation of the braking force is started. . Due to this load movement, a braking force is quickly generated on the front wheels 2FL and 2FR, so that a high deceleration and a short stopping distance can be obtained. If the sum of the energy for operating the front braking device 1F and the energy for operating the rear braking device 1R is constant, the braking force on the front side (distribution) should be greater than the braking force on the rear side. , Higher deceleration can be obtained (energy efficient).

  The control unit 92 can execute the first control, the second control, and the third control, and selects and executes one of them. In the first control, after operating the rear braking device 1R, the front braking device 1F is operated. Therefore, at least when the generation of the braking force is started, the rear-side braking force becomes larger than the front-side braking force. Note that the operation start timing of the front braking device 1F can be set, for example, after a time point when it can be determined that the pitching behavior of the vehicle can be sufficiently suppressed. In the third control, after the front braking device 1F is operated, the rear braking device 1R is operated or only the front braking device 1F is operated. Therefore, at least when the generation of braking force is started, the braking force on the front side becomes larger than the braking force on the rear side. Note that the operation start timing of the rear braking device 1R can be set after, for example, a time when it can be determined that the load has sufficiently moved to the front wheels 2FL, 2FR. In the second control, the front braking device 1F is operated and the rear braking device 1R is operated. Therefore, in situations where the required deceleration is moderate, at least at the start of braking force generation, the front side braking force and the rear side braking force are equivalent, which increases discomfort due to deceleration to the occupant. While stopping, the stop distance can be shortened. For example, the vehicle requires three deceleration states where the deceleration required is low, medium, and high, and the first control, second control, and third control operate in these braking states, respectively. Is confirmed, the operation of the control unit of the present embodiment is presumed.

  4 to 9 illustrate various patterns (response waveforms) of the time change of the braking force g during the first to third controls. The vertical axis represents braking force g and the horizontal axis represents time t. The target braking force G is indicated by a rough broken line. The braking force g (F) applied to the front wheels 2FL and 2FR when the control unit operates the hydraulic control unit 6 is indicated by a fine broken line. The braking force g (R) applied to the rear wheels 2RL and 2RR when the control unit operates the electric braking mechanisms 7RL and 7RR is indicated by a one-dot chain line. The braking force g (F + R) by the sum of g (F) and g (R) is shown by a solid line. Assume that the brake pedal 3 is depressed and the stroke amount increases from zero with a constant gradient and then is maintained at a constant value. In accordance with the change in stroke amount, the target braking force G increases from zero with a constant gradient and then becomes a constant value.

  4 to 7 show response waveforms of the braking force g when the operation of the hydraulic pressure control unit 6 is started (at the time of the first control) after the operation of the electric braking mechanisms 7RL and 7RR is started. The rear braking force g (R) is generated prior to the front braking force g (F). The gradient (increase speed) and distribution of the braking forces g (F) and g (R) may be appropriately changed according to the characteristics of the vehicle, the road surface conditions, and the like. The various patterns are illustrated in FIGS.

  In the example shown in FIG. 4, the gradient of g (F) and the gradient of g (R) are substantially the same, and the final (after becoming constant) magnitude of g (F) and g (R) The ratio (allocation) is larger for g (R) than for g (F). At time t41, the operation of the electric braking mechanisms 7RL and 7RR is started. After g (R) increases with a constant gradient from t41 to t44, it becomes a constant value. After a predetermined time has elapsed from time t41, the operation of the hydraulic pressure control unit 6 is started at t42. g (F) increases from t42 to t44 with the same gradient as g (R), and then becomes a constant value smaller than g (R). g (F + R) increases with approximately the same gradient as G after t42. G (F + R) coincides with G at t44 later than t43 where G is a constant value.

  In the example shown in FIG. 5, the gradient of g (F) and the gradient of g (R) are substantially the same, and the final sizes of g (F) and g (R) are also approximately the same. At time t51, the operation of the electric braking mechanisms 7RL and 7RR is started. After g (R) increases with a constant gradient from t51 to t54, it becomes a constant value. After a predetermined time has elapsed from time t51, the operation of the hydraulic pressure control unit 6 is started at t52. g (F) increases from t52 to t55 with the same gradient as g (R), and then becomes the same constant value as g (R). g (F + R) increases with the same gradient as G after t52, and increases with the same gradient as g (F) after t54. G (F + R) coincides with G at t55 which is slower than t53 where G is a constant value.

  In the example shown in FIG. 6, the gradient of g (F) is larger than the gradient of g (R), and the final sizes of g (F) and g (R) are substantially the same. At time t61, the operation of the electric braking mechanisms 7RL and 7RR is started. After g (R) increases with a constant gradient from t61 to t64, it becomes a constant value. After a predetermined time has elapsed from time t61, the operation of the hydraulic pressure control unit 6 is started at t62. g (F) increases from t62 to t64 with a gradient greater than g (R), and then becomes the same constant value as g (R). g (F + R) increases with a gradient greater than G after t62. At t64, which is slightly later than t63 where G is a constant value, g (F + R) matches G.

  In the example shown in FIG. 7, the gradient of g (F) is larger than the gradient of g (R), and the final size of g (F) is also larger than the final size of g (R). At time t71, the operation of the electric braking mechanisms 7RL and 7RR is started. After g (R) increases with a constant gradient from t71 to t73, it becomes a constant value. After a predetermined time has elapsed from time t71, the operation of the hydraulic pressure control unit 6 is started at t72. g (F) increases from t72 to t75 with a gradient greater than g (R), and then becomes a constant value greater than g (R). g (F + R) increases with a gradient greater than G after t72, and increases with the same gradient as g (F) after t73. At t75, which is slightly later than t74 where G is a constant value, g (F + R) matches G.

  FIG. 8 illustrates a response waveform of the braking force g when the operation of the electric braking mechanisms 7RL and 7RR and the operation of the hydraulic pressure control unit 6 are started substantially simultaneously (during the second control). The front braking force g (F) and the rear braking force g (R) are generated almost simultaneously. At time t81, the hydraulic pressure control unit 6 and the electric braking mechanisms 7RL and 7RR are started to operate. After g (F) and g (R) increase with substantially the same constant gradient from t81 to t83, they become substantially the same constant value. g (F + R) increases with approximately the same gradient as G after t81. At t83 which is slightly later than t82 where G is a constant value, g (F + R) coincides with G.

  FIG. 9 illustrates the response waveform of the braking force g when the operation of the electric braking mechanisms 7RL and 7RR is started (during the third control) after the operation of the hydraulic pressure control unit 6 is started. The braking force g (F) on the front side is generated prior to the braking force g (R) on the rear side. The operation of the hydraulic pressure control unit 6 is started at time t91. After g (F) increases from t91 to t93 with a constant gradient slightly smaller than G, it reaches a constant value. After t91 (also before t91), the electric braking mechanisms 7RL and 7RR do not operate. g (F + R) changes with the same value as g (F) after t91. At t93, which is slower than t92 where G is a constant value, g (F + R) matches G.

  In addition, in order to switch the difference between the braking force g (F) on the front side and the braking force g (R) on the rear side, not only the generation timing of g (F) and g (R) is shifted, but also Instead, a difference may be made between the gradients of g (F) and g (R). For example, in the first control, the front braking device 1F is operated and the rear braking device 1R is operated, and the gradient of the rear braking force g (R) is controlled on the front side for a predetermined period including immediately after the start of these operations. Make it larger than the gradient of power g (F). Thereby, at least when the generation of the braking force is started, g (R) becomes larger than g (F). In the third control, the front braking device 1F is operated and the rear braking device 1R is operated, and the gradient of g (F) is made larger than the gradient of g (R) for a predetermined period including immediately after the start of these operations. Thereby, at least at the start of generation of the braking force, g (F) becomes larger than g (R).

  The control unit 92 can switch between the first control, the second control, and the third control in accordance with a value representing the deceleration required for the vehicle. Therefore, a suitable one of the three control modes can be selected according to the deceleration required for the vehicle. The “value indicating the deceleration required for the vehicle” is the target braking force G. The target braking force G is calculated based on the detection value of the stroke sensor 81 and the detection signal of the external recognition device 80 input from the input unit 91. The detection value of the stroke sensor 81 is information on the deceleration required for the vehicle. The above-mentioned “information about the deceleration required for the vehicle” is calculated from the detection value and the detection signal in addition to the value detected by the sensor 81 and the signal itself detected by the recognition device 80, and is input to the control unit 92. Information. The control unit 92 is not limited to the target braking force G, and the control mode may be switched using the “information regarding deceleration required for the vehicle” input from the input unit 91 as it is.

  The “information regarding deceleration required for the vehicle” includes a detection value of the stroke sensor 81. The detection value of the stroke sensor 81 reflects the brake operation state of the driver. Therefore, it is possible to optimize the braking state by switching the control mode according to the driver's intention to brake (deceleration required for the vehicle by the driver).

  4 to 9 show simple patterns in which the control mode does not change from the beginning. However, the target braking force G actually fluctuates, and the control mode is switched when the fluctuating G crosses the threshold values G1 and G2. FIG. 10 exemplifies various patterns of time change of the target braking force G when the target braking force G is calculated according to the stroke amount. In general, when the increasing gradient of G (the depression speed of the brake pedal 3) is large, the braking force intended by the driver is large, and the final value of G (the depression amount of the brake pedal 3) is large. α indicates a case where the increasing gradient of G is small and the final value of G is a constant value less than the first threshold value G1. γ indicates a case where the increasing gradient of G is large and the final value of G is a constant value equal to or greater than the second threshold G2. β represents a case where the increasing gradient of G is between α and β, and the final value of G is a constant value not less than G1 and less than G2. As shown in the examples of β and γ, while G increases from zero to a final constant value, the control mode is switched to cross the thresholds G1 and G2. Therefore, the control unit 92 may predict in advance what value the target braking force G will eventually have. In other words, the control unit 92 increases the target braking force G (“the value representing the deceleration required for the vehicle”) as the amount of change in the brake operation obtained from the detection value of the stroke sensor 81 increases. Good. Specifically, in step S2, the control unit 92 calculates G based on the stroke amount change gradient. The target braking force G is increased as the change rate of the stroke amount (change amount of the brake operation) is increased. Note that G may be calculated based on a change gradient such as a pedal effort. As a result, a control mode that more accurately reflects the driver's intention can be realized, and a simple pattern in which the control mode does not change from the beginning as shown in FIGS. 4 to 9 is realized relatively frequently. In other words, frequent switching of the control mode can be suppressed.

  11 and 12 exemplify response waveforms when G varies and crosses thresholds G1 and G2 (control mode switching occurs) when G is calculated based on the change gradient of the stroke amount S. FIG. In the example shown in FIG. 11, the control mode is switched from the second control to the first control. The change gradient of the stroke amount S is intermediate from time t111 to t112, and is small from t112 to t115. Therefore, G is calculated to be medium from t111 to t112 and is in region A2. From t112 to t115 is calculated to be small and is in region A1. Therefore, the second control is executed from t111 to t112, and the control mode is switched to the first control at t112. g (F) and g (R) change from t111 to t112 in the same manner as from t81 to t82 in FIG. 8, and change from t112 to t115 in the same manner from t51 to t55 in FIG.

  In the example shown in FIG. 12, the control mode is switched from the second control to the third control. The change gradient of the stroke amount S is medium from time t121 to t122, and is large from t122 to t123. Therefore, G is calculated to be medium from t121 to t122 and is in the region A2. From t122 to t123 is greatly calculated and is in region A3. Therefore, the second control is executed from t121 to t122, and the control mode is switched to the third control at t122. g (F) and g (R) change from t121 to t122 in the same manner as from t81 to t82 in FIG. 8, and from t122 to t123 in the same manner as from t91 to t93 in FIG. However, after t122, unlike FIG. 9, the electric braking mechanisms 7RL and 7RR are operated to maintain (hold) g (R) at t122. Thereby, g (F) is substantially made larger than g (R).

  The “information regarding deceleration required for the vehicle” includes a detection signal of the external recognition device 80. The detection signal of the external recognition device 80 is information related to the outside world of the vehicle (relationship between the preceding vehicle and the obstacle and the host vehicle). Therefore, for example, according to the deceleration required for the vehicle in automatic brake control, the control mode can be switched to optimize the braking state.

  The controller 92 obtains the target braking force G (vehicle) as the vehicle speed is larger than the speed of the object (preceding vehicle or obstacle) in the traveling direction of the vehicle obtained from the detection signal of the external recognition device 80. (Value indicating the deceleration required). As described above, the larger the relative speed, the larger the target braking force G (the smaller the relative speed, the smaller the target braking force G), which is required for the vehicle in the follow-up control to the preceding vehicle and the emergency avoidance control of the obstacle. It is possible to switch the control mode appropriately according to the deceleration. For example, during the follow-up control to the preceding vehicle, the execution of the first control is promoted more than the third control by reducing the target braking force G as the difference in speed between the preceding vehicle and the host vehicle is smaller. As a result, in a situation where the relative speed is small and the deceleration required for the vehicle is low, the braking force on the rear side becomes larger than the braking force on the front side, so the load fluctuation of the vehicle toward the front wheels 2FL, 2FR It becomes gentle and the pitching behavior of the vehicle is reduced, and the ride comfort is improved. On the other hand, during the collision avoidance control with the obstacle, the execution of the third control is promoted more than the first control by increasing the target braking force G as the speed of the host vehicle with respect to the obstacle increases. As a result, in a situation where the relative speed is high and the deceleration required for the vehicle is high, the braking force on the front side becomes larger than the braking force on the rear side, so the vehicle load is quickly moved toward the front wheels 2FL, 2FR. Move and get high deceleration and short stopping distance.

  Specific means for switching the control mode in accordance with a value (target braking force G) indicating the deceleration required for the vehicle is arbitrary. In the present embodiment, the control unit 92 determines switching of the control mode using the threshold values G1 and G2. The control unit 92 switches to the first control when the target braking force G is less than the first threshold G1, and switches to the second control when the target threshold G is equal to or greater than the first threshold G1 and less than the second threshold G2, and is equal to or greater than the second threshold G2. Switch to 3rd control at Therefore, the control configuration can be simplified.

  The control unit 92 corrects the first threshold value G1 and the second threshold value G2 to a smaller value than when the vehicle speed is small, or an object (preceding vehicle or obstacle) in the traveling direction of the vehicle. When the distance to the vehicle is short, it is corrected to a smaller value than when it is long, or when the friction coefficient μ of the road surface in contact with the wheel 2 is small, it is corrected to a smaller value than when it is large. As described above, the thresholds G1 and G2 are lowered in a situation where the required stop distance is long (vehicle speed is high, road surface μ is small) and a required stop distance is short (relative distance is short). Therefore, the execution of the second control is promoted more than the first control, and the execution of the third control is promoted more than the second control, so that the vehicle load is quickly moved toward the front wheels 2FL and 2FR, and the brake is It becomes effective and a short stop distance can be obtained. Conversely, in situations where the required stop distance is short (the vehicle speed is low and the road surface μ is large) or the required stop distance is long (the relative distance is long), the threshold values G1 and G2 are increased. Therefore, the execution of the second control is promoted more than the third control, and the execution of the first control is promoted more than the second control. Therefore, the vehicle load fluctuations toward the front wheels 2FL and 2FR become gentle and stop. Even if the distance is a little longer, the ride is comfortable. The amount of correction can be set as appropriate for each of the vehicle speed, road surface μ, and relative distance. Each or one of G1 and G2 may be corrected by any one or a combination of the vehicle speed, the road surface μ, and the relative distance. The values related to the required stop distance and the required stop distance are not limited to the vehicle speed, the road surface μ, and the relative distance. A value related to the stop distance for correcting G1 may be different from a value related to the stop distance for correcting G2. Only one of G1 and G2 may be corrected.

  Both the front braking device 1F and the rear braking device 1R may be a hydraulic braking mechanism, or both may be an electric braking mechanism. The front braking device 1F may include only the electric braking mechanism, and the rear braking device 1R may include only the hydraulic braking mechanism. In the present embodiment, the front braking device 1F includes a hydraulic control unit 6 and a wheel cylinder 19FL, 19FR (hydraulic braking mechanism) that can apply a braking force to the wheels 2FL, 2FR by propelling a piston (braking member) with hydraulic pressure. )including. Rear braking device 1R includes electric braking mechanisms 7RL and 7RR that can apply a braking force to wheels 2RL and 2RR by propelling a piston (braking member) with a motor (electric motor). In general, the electric braking mechanism is more responsive to braking force control than the hydraulic braking mechanism. Therefore, when the first control is executed, that is, when the braking force g (R) on the rear side is substantially larger than the braking force g (F) on the front side, g ( Since R) is generated with good response, the response of braking force control can be improved. Also, if a power failure occurs in the electric braking mechanisms 7RL, 7RR (rear braking device 1R), the hydraulic braking mechanism (front braking device 1F) will apply the braking force by the hydraulic pressure to the front wheels 2FL, 2FR. Therefore, the reliability of the braking system 1 can be improved. Even if a power failure occurs in the hydraulic braking mechanism (front braking device 1F), the hydraulic pressure control unit 6 can realize pedal force braking by supplying the master cylinder hydraulic pressure to the wheel cylinders 19FL and 19FR. .

[Second Embodiment]
First, the configuration will be described. The control unit 92 according to the present embodiment determines control mode switching using a map. As shown in FIG. 13, the map is a two-dimensional map with the vertical axis representing the target braking force G and the horizontal axis representing the vehicle speed V. A straight line connecting the first value G1 of the target braking force G and the first value V1 of the vehicle speed V is defined as L1. A straight line connecting the second value G2 of the target braking force G and the second value V2 of the vehicle speed V is defined as L2. Regions A1, A2, and A3 are separated by L1 and L2. The control unit 92 switches to the first control when the point determined by the current target braking force G and the current vehicle speed is in the region A1, switches to the second control when it is in the region A2, and when it is in the region A3. Switch to third control. As in the first embodiment, the control unit 92 corrects G1 and G2 according to values related to the stop distance (road surface μ, relative distance, etc.). Similarly to G1 and G2, V1 and V2 are corrected to V1 ′, V2 ′, V1 ″, and V2 ″ in accordance with values related to the stop distance (road surface μ, relative distance, etc.). For example, when the road surface μ is small, V1 and V2 are corrected to smaller values V1 ′ and V2 ′ than when the road surface μ is large. Alternatively, when the relative distance is short, V1 and V2 are corrected to smaller values V1 ′ and V2 ′ than when the relative distance is long. When G1, G2 and V1, V2 are corrected in this way, L1 and L2 are also corrected to L1 ′, L2 ′ and L1 ″ and L2 ″, respectively, and as a result, the areas A1 to A3 increase or decrease. . Other configurations are the same as those of the first embodiment.

  Next, the function and effect will be described. By using the map in this manner, the above determination can be easily performed while associating the parameters of the respective axes with each other. Note that L1 and L2 may be corrected by correcting only one of G1, G2 and V1, V2. Instead of the vehicle speed V, the horizontal axis of the map may be the road surface μ (reciprocal) or the relative distance (reciprocal). The control unit 92 uses a three-dimensional map in which the third axis is the road surface μ (the reciprocal) or the relative distance (the reciprocal), and the current state is in any of the spaces separated by the plane passing through the values of the respective axes. The switching of the control mode may be determined depending on whether it is located. Furthermore, the control unit 92 represents constants as a and b, and represents the discriminant value D by a mathematical formula such as D = aG + bV, so as to discriminate switching of the control mode depending on whether D exceeds a predetermined threshold. Good. Also in this case, the constants a and b and the threshold value may be made variable according to the road surface μ and the like.

[Third embodiment]
As shown in FIG. 14, the map of the present embodiment is a two-dimensional map with the vertical axis representing the target braking force G and the horizontal axis representing the vehicle speed V. Let L1 be a line composed of a line according to G1 (a line that is constant at G1 regardless of V) and a line according to V1 (a line that is constant at V1 regardless of G). Let L2 be a line composed of a line according to G2 (a line that is constant at G2 regardless of V) and a line according to V2 (a line that is constant at V2 regardless of G). Regions A1, A2, and A3 are separated by L1 and L2. As in the second embodiment, the control unit 92 corrects G1, G2, and V1, V2 in accordance with values related to the stop distance (road surface μ, relative distance, etc.). L1 and L2 are also corrected, and as a result, the areas A1 to A3 increase or decrease. Other configurations and operational effects are the same as those of the second embodiment.

[Fourth embodiment]
First, the configuration will be described. The rear braking device 1R of the present embodiment includes a hydraulic braking mechanism (hydraulic pressure control unit 6R and wheel cylinders 19RL and 19RR) and electric braking mechanisms 7RL and 7RR. The hydraulic control unit 6 is separate for the front braking device 1F and the rear braking device 1R. As shown in FIG. 15, the hydraulic control unit 6R of the rear braking device 1R has a hydraulic circuit, a solenoid valve, and a pump unit, like the hydraulic control unit 6F of the front braking device 1F, and the control hydraulic pressure is externally transmitted. Can be supplied. Only differences from the hydraulic pressure control unit 6F will be described below. The hydraulic pressure control unit 6R is connected to the branch pipes of the brake pipes 10I, 10P, and 10S and the brake pipes 10RL and 10RR. The plurality of solenoid valves have only the shut-off valve 61 and the pressure reducing valve 65. The pump 601 is provided separately for the P system and the S system. The hydraulic circuit has only the supply liquid path 11, the suction liquid path 12, the discharge liquid path 13, and the decompression liquid path 15. The discharge liquid paths 13P and 13S do not communicate with each other. The supply liquid path 11P is connected to the wheel cylinder 19RR of the rear right wheel 2RR via the brake pipe 10RR. The supply liquid path 11S is connected to the wheel cylinder 19RL of the rear left wheel 2RL via the brake pipe 10RL. In the supply liquid path 11P, there is no hydraulic pressure sensor between the brake pipe 10P (branch pipe) and the cutoff valve 61P, and there is a hydraulic pressure sensor 83P between the cutoff valve 61P and the brake pipe 10RR. There is no fluid pressure sensor in the supply fluid passage 11S. The control unit 9R of the rear braking device 1R is integrated with the hydraulic control unit 6R. Both units 9R and 6R may be separate.

  As shown in FIG. 16, the rear right wheel 2RR includes a wheel cylinder 19RR and an electric braking mechanism 7RR. The wheel cylinder 19RR is a caliper having a cylinder 101 and a piston 102. The hydraulic pressure supplied from the brake pipe 10RR to the cylinder 101 propels the piston 102. When the piston 102 presses the brake pad 21 against the disc rotor (brake disc) 20, a braking force is applied to the rear right wheel 2RR. The electric braking mechanism 7RR includes a motor 70, a rotation-linear motion conversion mechanism 71, a caliper 72, and a sub CU 700. The rotation / linear motion conversion mechanism 71 propels the piston 720 of the caliper 72 by the rotation of the motor 70. The piston 720 presses the brake pad 22 against the brake disc 20, whereby braking force is applied to the rear right wheel 2RR. The caliper (wheel cylinder 19RR) of the hydraulic braking mechanism and the caliper 72 of the electric braking mechanism 7RR are provided separately. The hydraulic pressure control unit 6R (wheel cylinder 19RR) and the electric braking mechanism 7RR operate independently of each other, and can apply braking force to the rear right wheel 2RR independently of each other. The same applies to the rear left wheel 2RL. Other configurations are the same as those of the first embodiment.

  Next, the function and effect will be described. The rear braking device 1R includes a hydraulic braking mechanism (hydraulic pressure control unit 6R and wheel cylinders 19RL, 19RR) and electric braking mechanisms 7RL, 7RR. Therefore, if the power failure of the electric braking mechanism 7RL, 7RR occurs, not only can the front braking device 1F apply a braking force by hydraulic pressure (hydraulic braking force) to the front wheels 2FL, 2FR, Since the rear braking device 1R can apply the hydraulic braking force to the rear wheels 2RL and 2RR, the reliability of the braking system 1 can be further improved.

  The hydraulic braking mechanism (hydraulic pressure control unit 6R and wheel cylinders 19RR, 19RL) and the electric braking mechanisms 7RL, 7RR (caliper 72) can apply braking force to the wheels 2RL, 2RR independently of each other. Therefore, it is possible to suppress the control by the hydraulic braking mechanism (specifically, the control by the hydraulic pressure control unit 6R) from affecting the control by the electric braking mechanisms 7RL and 7RR. The calipers of the braking mechanisms of the wheels 2RL and 2RR may be redundant systems, and may have two or more calipers that can be operated by hydraulic pressure and two or more calipers that can be operated by the driving force of the motor. Further, there may be a plurality of pistons in one caliper, at least one piston can be operated by hydraulic pressure, and at least one of the other pistons can be operated by a driving force of a motor. Further, the wheel cylinder 19 and the electric braking mechanism 7 may be provided on the front wheels 2FL and 2FR together with the rear wheels 2RL and 2RR or instead of the rear wheels 2RL and 2RR. Other functions and effects are the same as those of the first embodiment.

[Fifth Embodiment]
First, the configuration will be described. The rear braking device 1R of the present embodiment includes a hydraulic braking mechanism (hydraulic control unit 6 and wheel cylinders 19RL, 19RR) and electric braking mechanisms 7RL, 7RR. The hydraulic control unit 6 is common to the front braking device 1F and the rear braking device 1R. Hereinafter, only the difference between the hydraulic pressure control unit 6 and the first embodiment will be described. As shown in FIG. 17, the pressure increasing valve 62 side of the supply liquid passage 11P with respect to the shutoff valve 61 branches into a liquid passage 11FL and a liquid passage 11RR. The liquid path 11RR is connected to the wheel cylinder 19RR of the rear right wheel 2RR via the brake pipe 10RR. The configuration of the liquid path 11RR is the same as that of the liquid path 11FL. The pressure increasing valve 62 side of the supply liquid path 11S with respect to the shutoff valve 61 branches into the liquid path 11FR and the liquid path 11RL. The liquid passage 11RL is connected to the wheel cylinder 19RL of the rear left wheel 2RL via the brake pipe 10RL. The configuration of the liquid path 11RL is the same as that of the liquid path 11FR. As in the fourth embodiment, the rear wheels 2RL and 2RR include wheel cylinders 19RL and 19RR and electric braking mechanisms 7RL and 7RR. Other configurations are the same as those of the fourth embodiment.

  Next, the function and effect will be described. The wheel cylinders 19RL and 19RR of the rear wheels 2RL and 2RR are connected to the downstream side (discharge side) of the hydraulic pressure source (pump 601) in the hydraulic pressure circuit of the hydraulic pressure control unit 6. Therefore, the wheel cylinders 19RL and 19RR can be increased by the brake fluid discharged from the pump 601. Therefore, in order to include the hydraulic braking mechanism in the rear braking device 1R, the pump 601 of the front braking device 1F can be used, and there is no need to add an additional hydraulic pressure source to the rear braking device 1R. Similarly, the wheel cylinders 19RL and 19RR are connected to the downstream side of the shutoff valve 61 (the discharge side of the pump 601) in the hydraulic circuit of the hydraulic pressure control unit 6. Therefore, the shutoff valve 61 can shut off the master cylinder 5 and the wheel cylinders 19RL and 19RR. Therefore, in order to include the hydraulic braking mechanism in the rear braking device 1R, the shut-off valve 61 of the front braking device 1F can be diverted, and the electromagnetic valve added to the rear braking device 1R can be suppressed. Further, the hydraulic pressure sensor 83 and the like can be shared. Instead of the rear wheels 2RL and 2RR, the front wheels 2FL and 2FR may include the wheel cylinder 19 and the electric braking mechanism 7. Other functions and effects are the same as those of the fourth embodiment.

[Sixth embodiment]
First, the configuration will be described. As shown in FIG. 18, the front left wheel 2FL of the present embodiment includes a wheel cylinder 19FL and an electric braking mechanism 7FL. The front right wheel 2FR includes a wheel cylinder 19FR and an electric braking mechanism 7FR. Other configurations are the same as those of the fifth embodiment.

  Next, the function and effect will be described. The front braking device 1F includes a hydraulic braking mechanism (hydraulic pressure control unit 6 and wheel cylinders 19FL, 19FR) and an electric braking mechanism 7FL, 7FR, and the rear braking device 1R includes a hydraulic braking mechanism (hydraulic pressure control unit 6 and Wheel cylinders 19RL, 19RR) and electric braking mechanisms 7RL, 7RR. Therefore, even if any of the wheels 2 can no longer be applied with the braking force due to the hydraulic pressure due to liquid leakage in the brake pipe 10, the braking force can be applied by the electric braking mechanism 7. Further, the reliability of the braking system 1 can be further improved. Further, when the third control is executed, that is, when the braking force g (F) on the front side is substantially larger than the braking force g (R) on the rear side, g ( By generating F) with good response, the response of braking force control can be improved. Other functions and effects are the same as those of the fifth embodiment.

[Other Embodiments]
As mentioned above, although the form for implementing this invention was demonstrated based on drawing, the specific structure of this invention is not limited to embodiment, The design change etc. of the range which does not deviate from the summary of invention are included. Even if it exists, it is included in this invention. For example, the specific configuration of the hydraulic braking mechanism or the electric braking mechanism is not limited to that of the embodiment. The hydraulic pressure source in the hydraulic pressure control unit is not limited to the pump unit, and may include an accumulator, a piston that is driven by an electric motor and generates hydraulic pressure, and the like. As the hydraulic braking mechanism, an electric booster (a mechanism that assists the driving force of the piston of the master cylinder using the electric motor as a power source) or the like may be used instead of or together with the hydraulic pressure control unit. In the embodiment, the control unit and the input unit of the control unit are realized by software in the microcomputer, but may be realized by an electronic circuit. The calculation means not only mathematical calculation but also general processing on software. The input unit may be an interface of a microcomputer or software in the microcomputer. The command signal may relate to a current value or may relate to torque.

[Technical ideas that can be grasped from the embodiment]
A technical idea (or technical solution, the same applies hereinafter) that can be grasped from the embodiment described above will be described below.
(1) The vehicle braking control device of the present technical idea, in one aspect thereof,
An input unit for inputting information on deceleration required for the vehicle;
Information about the input deceleration is the difference between the braking force applied to the front wheels of the vehicle by operating the front braking device and the braking force applied to the rear wheels of the vehicle by operating the rear braking device. And a control unit that can be switched according to.
(2) In a more preferred embodiment, in the above embodiment,
When the deceleration required for the vehicle is high, the control unit applies the braking force applied to the front wheels of the vehicle by operating the front braking device at least at the start of applying the braking force, rather than when the braking force is low. By operating the rear braking device, the braking force applied to the rear wheel of the vehicle is made larger.
(3) In another preferred embodiment, in any of the above embodiments,
When the deceleration required for the vehicle is low, the control unit applies the braking force applied to the front wheels of the vehicle by operating the front braking device at least at the start of applying the braking force than when the vehicle is high. By operating the rear braking device, the braking force applied to the rear wheel of the vehicle is made smaller.
(4) In still another preferred embodiment, in any of the above embodiments,
The controller is
A first control for operating the front braking device after operating the rear braking device;
A second control for operating the front braking device and operating the rear braking device;
After operating the front braking device, it is possible to execute the third control that operates the rear braking device or only the front braking device.
(5) In still another preferred embodiment, in any of the above embodiments,
The control unit can switch between the first control, the second control, and the third control in accordance with the input information related to deceleration.
(6) In still another preferred embodiment, in any of the above embodiments,
The control unit switches to the first control when a value representing a deceleration required for the vehicle obtained from the input information is less than a first threshold, and is greater than or equal to the first threshold and a second threshold When the value is less than the value, the control is switched to the second control, and when the value is equal to or greater than the second threshold, the control is switched to the third control.
(7) In still another preferred embodiment, in any of the above embodiments,
The input information on deceleration includes information on a driver's brake operation acquired by a sensor.
(8) In still another preferred embodiment, in any of the above embodiments,
The control unit increases the value representing the deceleration required for the vehicle as the amount of change in the brake operation obtained from the input information increases.
(9) In still another preferred embodiment, in any of the above embodiments,
The information regarding the input deceleration includes information regarding the outside world of the vehicle acquired by a sensor.
(10) In still another preferred embodiment, in any of the above embodiments,
The control unit increases a value representing a deceleration required for the vehicle as the vehicle speed is larger than the speed of the object in the traveling direction of the vehicle obtained from the input information. .
(11) In still another preferred embodiment, in any of the above embodiments,
The control unit sets the first threshold value and the second threshold value,
When the speed of the vehicle is large, correct to a smaller value than when it is small, or
When the distance between the object in the traveling direction of the vehicle and the vehicle is short, correct to a smaller value than when the distance is long, or
When the coefficient of friction of the road surface in contact with the vehicle wheel is small, it is corrected to a smaller value than when it is large.
(12) In still another preferred embodiment, in any of the above embodiments,
The front braking device includes a hydraulic braking mechanism capable of applying a braking force to the wheels of the vehicle by propelling a braking member with hydraulic pressure,
The rear braking device includes an electric braking mechanism that can apply a braking force to the wheels of the vehicle by propelling a braking member with an electric motor.
(13) In still another preferred embodiment, in any of the above embodiments,
The rear braking device includes the hydraulic braking mechanism and the electric braking mechanism.
(14) In still another preferred embodiment, in any of the above embodiments,
The hydraulic braking mechanism and the electric braking mechanism can apply braking force to the wheels of the vehicle independently of each other.
(15) In still another preferred embodiment, in any of the above embodiments,
The front braking device includes the hydraulic braking mechanism and the electric braking mechanism,
The rear braking device includes the hydraulic braking mechanism and the electric braking mechanism.
(16) Further, from another viewpoint, the vehicle braking control method of the present technical idea is, in one aspect thereof,
The control unit
Obtaining information about the deceleration required for the vehicle;
The difference between the braking force applied to the front wheels of the vehicle by operating the front braking device and the braking force applied to the rear wheels of the vehicle by operating the rear braking device is the information on the acquired deceleration. Switch accordingly.
(17) In a more preferred embodiment, in the above embodiment,
The control device is
A first control for operating the front braking device after operating the rear braking device;
A second control for operating the front braking device and operating the rear braking device;
After the front braking device is operated, either the rear braking device or the third control for operating only the front braking device is selected and executed.
(18) In another preferred embodiment, in any of the above embodiments,
The control device switches between the first control, the second control, and the third control in accordance with the acquired information regarding the deceleration.
(19) In still another preferred embodiment, in any of the above embodiments,
The control device switches to the first control when a value indicating deceleration required for the vehicle obtained from the acquired information is less than a first threshold, and is greater than or equal to the first threshold and less than a second threshold. At the time of switching to the second control, and to the third control at or above the second threshold.
(20) In still another preferred embodiment, in any of the above embodiments,
The front braking device includes a hydraulic braking mechanism capable of applying a braking force to the wheels of the vehicle by propelling a braking member with hydraulic pressure,
The rear braking device includes an electric braking mechanism that can apply a braking force to the wheels of the vehicle by propelling a braking member with an electric motor.
(21) Further, from another viewpoint, the vehicle braking system of the present technical idea is, in one aspect thereof,
A front braking device for applying braking force to the front wheels of the vehicle;
A rear braking device for applying a braking force to the rear wheels of the vehicle;
A control unit capable of controlling the front braking device and the rear braking device,
An input unit for inputting information on deceleration required for the vehicle;
The difference between the braking force applied to the front wheels of the vehicle by operating the front braking device and the braking force applied to the rear wheels of the vehicle by operating the rear braking device is information relating to the input deceleration. And a control unit having a control unit that can be switched in accordance with the control unit.
(22) In a more preferred embodiment, in the above embodiment,
The controller is
A first control for operating the front braking device after operating the rear braking device;
A second control for operating the front braking device and operating the rear braking device;
After operating the front braking device, it is possible to execute the third control that operates the rear braking device or only the front braking device.
(23) In another preferred embodiment, in any of the above embodiments,
The control unit can switch between the first control, the second control, and the third control in accordance with the input information related to deceleration.
(24) In still another preferred embodiment, in any of the above embodiments,
The control unit switches to the first control when a value representing a deceleration required for the vehicle obtained from the input information is less than a first threshold, and is greater than or equal to the first threshold and a second threshold When the value is less than the value, the control is switched to the second control, and when the value is equal to or greater than the second threshold, the control is switched to the third control.
(25) In still another preferred embodiment, in any of the above embodiments,
The front braking device includes a hydraulic braking mechanism capable of applying a braking force to the wheels of the vehicle by propelling a braking member with hydraulic pressure,
The rear braking device includes an electric braking mechanism that can apply a braking force to the wheels of the vehicle by propelling a braking member with an electric motor.

1 Braking System 1F Front Braking Device 1R Rear Braking Device 2FL Front Left Wheel 2FR Front Right Wheel 2RL Rear Left Wheel 2RR Rear Right Wheel 81 Stroke Sensor 9F Front Control Unit (Vehicle Braking Control Device)
9R Rear control unit (vehicle braking control device)
91 Input unit 92 Control unit

Claims (15)

An input unit for inputting information on deceleration required for the vehicle;
Information about the input deceleration is the difference between the braking force applied to the front wheels of the vehicle by operating the front braking device and the braking force applied to the rear wheels of the vehicle by operating the rear braking device. A vehicle braking control device comprising: a control unit that can be switched according to The vehicle braking control device according to claim 1,
The controller is
A first control for operating the front braking device after operating the rear braking device;
A second control for operating the front braking device and operating the rear braking device;
After actuating the front braking device, it is possible to perform the third control to activate the rear braking device or activate only the front braking device.
Vehicle braking control device. The vehicle braking control device according to claim 2,
The said control part is a vehicle braking control apparatus which can switch said 1st control, said 2nd control, and said 3rd control according to the information regarding the said deceleration input. In the vehicle braking control device according to claim 3,
The control unit switches to the first control when a value representing a deceleration required for the vehicle obtained from the input information is less than a first threshold, and is greater than or equal to the first threshold and a second threshold A vehicle braking control device that switches to the second control when the value is less than the threshold value, and switches to the third control when the value is equal to or greater than the second threshold value. The vehicle braking control device according to claim 4, wherein
The information on the input deceleration is a vehicle braking control device including information on a driver's brake operation acquired by a sensor. The vehicle braking control device according to claim 5, wherein
The said control part is a vehicle braking control apparatus which enlarges the value showing the deceleration requested | required of the said vehicle, so that the variation | change_quantity of the said brake operation obtained from the said input information is large. The vehicle braking control device according to claim 4, wherein
The information on the input deceleration is a vehicle braking control device including information on the outside of the vehicle acquired by a sensor. The vehicle braking control device according to claim 7, wherein
The control unit increases a value representing a deceleration required for the vehicle as the vehicle speed is larger than the speed of the object in the traveling direction of the vehicle obtained from the input information. Vehicle braking control device. The vehicle braking control device according to claim 4, wherein
The control unit sets the first threshold value and the second threshold value,
When the speed of the vehicle is large, correct it to a smaller value than when it is small, or
When the distance between the object in the traveling direction of the vehicle and the vehicle is short, correct to a smaller value than when the distance is long, or
When the friction coefficient of the road surface in contact with the wheel of the vehicle is small, it is corrected to a smaller value than when it is large.
Vehicle braking control device. The vehicle braking control device according to claim 1,
The front braking device includes a hydraulic braking mechanism capable of applying a braking force to the wheels of the vehicle by propelling a braking member with hydraulic pressure,
The rear braking device includes an electric braking mechanism capable of applying a braking force to the wheels of the vehicle by propelling a braking member with an electric motor.
Vehicle braking control device. The vehicle braking control device according to claim 10, wherein
The rear braking device is a vehicle braking control device including the hydraulic braking mechanism and the electric braking mechanism. The vehicle braking control device according to claim 11, wherein
The vehicle braking control device, wherein the hydraulic braking mechanism and the electric braking mechanism can apply braking force to the wheels of the vehicle independently of each other. The vehicle braking control device according to claim 10, wherein
The front braking device includes the hydraulic braking mechanism and the electric braking mechanism,
The rear braking device includes the hydraulic braking mechanism and the electric braking mechanism.
Vehicle braking control device. The control unit
Get information about the deceleration required for the vehicle,
The difference between the braking force applied to the front wheels of the vehicle by operating the front braking device and the braking force applied to the rear wheels of the vehicle by operating the rear braking device is the information on the acquired deceleration. Switch accordingly
Vehicle braking control method. A braking system for a vehicle,
A front braking device for applying a braking force to the front wheels of the vehicle;
A rear braking device for applying a braking force to the rear wheels of the vehicle;
A control unit capable of controlling the front braking device and the rear braking device,
An input unit for inputting information on deceleration required for the vehicle;
The difference between the braking force applied to the front wheels of the vehicle by operating the front braking device and the braking force applied to the rear wheels of the vehicle by operating the rear braking device is information relating to the input deceleration. And a control unit having a control unit that can be switched according to the vehicle braking system.

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