Braking force control device for vehicle

Abstract

To provide a vehicular braking force control device capable of achieving both turning performance and quietness when a vehicle turns at a low speed.SOLUTION: A behavior stabilizer 21 of a vehicular braking force control device 1 includes: a plurality of first valves 22a-22d for controlling movement of a hydraulic fluid to a plurality of friction brakes 20a-20d, respectively; second valves 23a-23d for controlling movement of the hydraulic fluid to reservoirs 25a-25b; and a drive motor 27 for driving pumps 26a-26b for discharging the hydraulic fluid from the reservoirs 25a-25b into a path leading to a hydraulic pressure generator 12. When a vehicle 100 is in a state of turning at a prescribed vehicle speed or lower, a controller 50 executes turning control to control operation of an electric actuator 33 to cause the hydraulic pressure generator 12 to generate hydraulic pressure, and to control open / closed states of the first valves 22a-22d and the second valves 23a-23d to apply braking force to a plurality of wheels 110a-110d. In the turning control, driving of the drive motor 27 is brought into a stopped state.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a braking force control device for a vehicle. [Background technology]

[0002] In recent years, efforts to provide access to sustainable transport systems that take into consideration vulnerable transport users such as the elderly, people with disabilities, and children have been gaining momentum. To achieve this, we are focusing on research and development to further improve transport safety and convenience through development of vehicle livability.

[0003] Conventionally, when a vehicle is required to have a turning radius smaller than the minimum turning radius, such as when making a U-turn or parking in a narrow parking lot, a technique for performing turning control (vectoring control) by using a difference in driving force or braking force between the left and right wheels has been known. This type of technique is described, for example, in Patent Document 1. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-143753 Summary of the Invention [Problem to be solved by the invention]

[0005] Incidentally, while a vehicle is traveling, there are cases where turning control is performed by a downstream actuator (e.g., a VSA device, etc.) that is different from an upstream brake actuator (e.g., an actuator that operates a slave cylinder). However, the downstream actuator may employ a pump that generates a loud operating noise, and such a configuration poses a problem in terms of improving the vehicle's interior comfort, and therefore, improvement in quietness during low-speed turning is desired.

[0006] An object of the present invention is to provide a braking force control device for a vehicle that can achieve both turning performance and quietness when the vehicle is turning at low speed, thereby contributing to the development of a sustainable transportation system. [Means for solving the problem]

[0007] The present invention relates to a vehicle braking force control device (for example, the vehicle braking force control device 1 described later) that applies a braking force to a vehicle (for example, the vehicle 100 described later). The vehicle braking force control device includes a vehicle speed detection device (for example, the vehicle speed detection device 11 described later) that detects the vehicle speed of the vehicle, a plurality of friction brakes (for example, the friction brakes 20a to 20d described later) arranged on a plurality of wheels (for example, the wheels 110a to 110d described later) of the vehicle and driven by the hydraulic pressure of a working fluid, a hydraulic pressure generating device (for example, the hydraulic pressure generating device 12 described later) that generates a hydraulic pressure in the working fluid by the operation of an electric actuator (for example, the electric actuator 33 described later), a behavior stabilizing device (for example, the behavior stabilizing device 21 described later) that adjusts the hydraulic pressure of the working fluid supplied from the hydraulic pressure generating device and applies the adjusted hydraulic pressure to the plurality of friction brakes to stabilize the behavior of the vehicle, and a control device (for example, the control device 50 described later) that controls the operation of the behavior stabilizing device and adjusts the braking force applied to the plurality of wheels. The behavior stabilizing device includes a plurality of first valves (for example, the first valves 22a to 22d described later) that control the movement of the working fluid to each of the plurality of friction brakes, a reservoir (for example, the reservoirs 25a to 25b described later) from which the working fluid is discharged from a branch portion of a path (for example, the path 40 described later) of the working fluid between the plurality of first valves and the friction brakes, a second valve (for example, the second valves 23a to 23d described later) arranged between each of the plurality of first valves and the reservoir and controlling the movement of the working fluid to the reservoir, a pump (for example, the pumps 26a to 26b described later) that discharges the working fluid discharged to the reservoir by pressurization to a path from the reservoir to the hydraulic pressure generating device, and a drive motor (for example, the drive motor 27 described later) that drives the pump. When the vehicle is in a turning state at a vehicle speed equal to or lower than a predetermined vehicle speed, the control device controls the operation of the electric actuator to generate a hydraulic pressure by the hydraulic pressure generating device, and controls the opening and closing states of the first valve and the second valve to execute a turning control for applying a braking force to the plurality of wheels. In the turning control, the drive of the drive motor is stopped. It relates to a vehicle braking force control device.

[0008] Accordingly, when the vehicle is turning at a low speed, braking force can be applied to the wheels by the hydraulic pressure generated by the hydraulic pressure generating device without using a drive motor that drives a pump with a large operating noise. Therefore, it is possible to improve the merchandise value by reducing the operating noise caused by the pressurization of the hydraulic fluid while improving the turning performance.

[0009] In the turning control, the control device generates hydraulic pressure by the hydraulic pressure generating device, and controls the first valve corresponding to the turning inner wheel to an open valve state and the first valve corresponding to the turning outer wheel to a closed valve state to generate a braking force difference between the plurality of wheels.

[0010] Accordingly, without using a drive motor that drives a pump, it is possible to generate a braking force difference between the turning outer wheel and the turning inner wheel by controlling the opening and closing of the first valve, and it is possible to achieve both higher turning performance and quietness.

[0011] The vehicle braking force control device includes a brake operation detection unit (for example, a brake operation sensor 31 described later) that detects an operation of a brake operation element (for example, a brake pedal 30 described later) by a driver. In the turning control, when an operation of the brake operation element is detected, the control device generates hydraulic pressure by the hydraulic pressure generating device and sets the plurality of first valves to an open valve state.

[0012] Accordingly, even when an operation of the brake operation element is detected during turning control, it is possible to apply braking force by bringing all the wheels into a pressurized state by controlling the opening and closing of the first valve, and to realize prompt braking control while reducing the operating noise related to the pressurization of the hydraulic fluid.

[0013] In the turning control, when the operating force of the brake operation element is equal to or greater than a predetermined value, the control device generates hydraulic pressure by the hydraulic pressure generating device and sets the plurality of first valves to an open valve state. When the operating force of the brake operation element becomes less than the predetermined value in the turning control, the control device closes the second valve corresponding to the turning inner wheel and opens the second valve corresponding to the turning outer wheel.

[0014] Accordingly, when the operating force of the brake operator becomes less than a predetermined value from a value equal to or greater than the predetermined value during turning control, the hydraulic pressure to the friction brake that applies braking force to the turning outer ring is reduced. Prompt pressurization control and depressurization control in response to changes in the operation of the brake operator are achieved.

Advantages of the Invention

[0015] According to the present invention, it is possible to provide a braking force control device for a vehicle that can achieve both turning performance and quietness during low-speed turning of the vehicle.

Brief Description of the Drawings

[0016]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Modes for Carrying Out the Invention

[0017] Hereinafter, each embodiment of the present invention will be described with reference to the drawings. Referring to FIGS. 1 and 2, the overall configuration of the vehicle braking force control device 1 used in the vehicle 100 will be described. FIG. 1 is a functional block diagram showing the configuration of the vehicle braking force control device 1 according to an embodiment of the present invention. FIG. 2 is a schematic diagram showing the path 40 of the working fluid of the vehicle braking force control device 1 according to the present embodiment.

[0018] As shown in FIGS. 1 and 2, the vehicle braking force control device 1 includes a brake operation device 10, a vehicle speed detection device 11, a hydraulic pressure generation device 12, friction brakes 20a to 20d, pressure valves 15a to 15b, suction valves 16a to 16b, a pressure sensor 17, a behavior stabilization device 21, and a control device 50.

[0019] The brake operation device 10 controls the friction brakes 20a to 20d based on the operation of the brake pedal 30 as a brake operation element. The brake operation device 10 is, for example, a BOS (Brake Operating Simulator) that electrically controls the brake operation according to the operation force of the brake pedal 30. The brake operation device 10 of the present embodiment includes a brake operation sensor 31 as a brake operation detection that detects operation information such as the operation amount and the weight based on the operation of the cylinder 5 linked to the operation of the brake pedal 30. The operation information detected by the brake operation sensor 31 is transmitted to the control device 50 and used for the control of the hydraulic pressure generation device 12 described later.

[0020] The vehicle speed detection device 11 detects the vehicle speed, which is the speed of the vehicle 100. The vehicle speed detected by the vehicle speed detection device 11 is transmitted to the control device 50.

[0021] The hydraulic pressure generation device 12 is a slave cylinder that generates hydraulic pressure by moving the piston 32 by the electric actuator 33. The electric actuator 33 operates based on a command from the control device 50. The electric actuator 33 of the present embodiment is a drive device that pressurizes via a ball screw having a smaller operating noise than the pumps 26a to 26b described later.

[0022] The friction brakes 20a to 20d are wheel cylinders that are arranged on each wheel of the vehicle 100 and are driven by hydraulic pressure. The friction brake 20a is an RR caliper arranged on the rear right wheel. The friction brake 20b is an FL caliper arranged on the front left wheel. The friction brake 20c is an FR caliper arranged on the front right wheel. The friction brake 20d is an RL caliper arranged on the rear left wheel.

[0023] The pressure valves 15a to 15b operate to pressurize the hydraulic fluid supplied to the friction brakes 20a to 20d. The pressure valve 15a is arranged on the upstream side of the friction brakes 20a to 20b in the hydraulic fluid path 40, and the pressure valve 15b is arranged on the upstream side of the friction brakes 20c to 20d in the hydraulic fluid path 40. The pressure valves 15a to 15b are electrically controlled by the control device 50.

[0024] The suction valves 16a to 16b perform a suction operation to return the hydraulic fluid to the hydraulic pressure generating device 12 side. The suction valve 16a is arranged on the friction brakes 20a to 20b side, and the suction valve 16b is arranged on the friction brakes 20c to 20d side. The suction valves 16a to 16b are electrically controlled by the control device 50.

[0025] The pressure sensor 17 is a pressure detection unit that detects the pressure of the hydraulic fluid that operates the friction brakes 20a to 20d. The pressure information detected by the pressure sensor 17 is transmitted to the control device 50.

[0026] The steering operation sensor 18 detects the steering operation and transmits it to the control device 50. The control device 50 determines whether or not it is during a turning operation based on the detection value of the steering operation sensor 18.

[0027] The behavior stabilization device 21 is a VSA (Vehicle Stability Assist) device that adjusts the hydraulic pressure of the hydraulic fluid supplied by the hydraulic pressure generating device 12 and applies the adjusted hydraulic pressure to multiple friction brakes 20a to 20d to stabilize the behavior of the vehicle 100.

[0028] The behavior stabilization device 21 of this embodiment includes first valves 22a to 22d, second valves 23a to 23d, reservoirs 25a to 25b, pumps 26a to 26b, and a drive motor 27.

[0029] The first valves 22a to 22d are pressure retention valves arranged upstream of the plurality of friction brakes 20a to 20d in the hydraulic fluid path 40. The first valve 22a is arranged upstream of the friction brake 20a, the first valve 22b is arranged upstream of the friction brake 20b, the first valve 22c is arranged upstream of the friction brake 20c, and the first valve 22d is arranged upstream of the friction brake 20d. The operation of each of the plurality of first valves 22a to 22d is electrically controlled by the control device 50.

[0030] The second valves 23a to 23d are pressure reducing valves arranged upstream of the reservoirs 25a to 25b at branching portions branching from the downstream side of the first valves 22a to 22d in the path 40. The second valve 23a is arranged at a branching portion branching from the downstream side of the first valve 22a to the reservoir 25a side, and the second valve 23b is arranged at a branching portion branching from the downstream side of the first valve 22b to the reservoir 25a side. The second valve 23c is arranged at a branching portion branching from the downstream side of the first valve 22c to the reservoir 25b side, and the second valve 23d is arranged at a branching portion branching from the downstream side of the first valve 22d to the reservoir 25b side. The operation of each of the second valves 23a to 23d is electrically controlled by the control device 50.

[0031] The reservoirs 25a to 25b collect the hydraulic fluid discharged from the second valves 23a to 23d. The hydraulic fluid discharged from the second valve 23a and the second valve 23b is collected in the reservoir 25a through a branch portion. The hydraulic fluid discharged from the second valve 23c and the second valve 23d is collected in the reservoir 25b through a branch portion.

[0032] The pumps 26a to 26b pressurize the hydraulic fluid collected in the reservoirs 25a to 25b and discharge it into the path 40 of the hydraulic fluid leading to the hydraulic generator 12. The pump 26a pressurizes the hydraulic fluid in the reservoir 25a, and the pump 26b pressurizes the hydraulic fluid in the reservoir 25b.

[0033] The drive motor 27 transmits a driving force to the pumps 26a to 26b and operates the pumps 26a to 26b. The drive motor 27 is electrically driven and controlled by the control device 50. In the present embodiment, the drive motor 27 is in a stopped state during low-speed turning and is driven in a driving state other than low-speed turning. Note that the stopped state of the drive motor in the present embodiment includes a state equivalent to stopping the motor to such an extent that it does not affect quietness.

[0034] The control device 50 will be described. The control device 50 is a computer that executes various controls related to the running of the vehicle 100 such as brake operation. The control device 50 is composed of a processor, a main storage device such as a ROM (Read Only Memory) and a RAM (Random Access Memory), an auxiliary storage device such as a storage, and the like. Note that the control device 50 may be configured alone or may be configured by a plurality of computers.

[0035] Above, the overall configuration of the vehicle braking force control device 1 according to the present embodiment has been described. Next, the turning control of the vehicle 100 at low speed by the control device 50 according to the present embodiment will be described.

[0036] Referring to FIGS. 3 and 4, the first turning control executed when no braking operation is performed during a low-speed turn will be described. FIG. 3 is a schematic diagram showing the braking forces applied to wheels 110a to 110d by the first turning control of the vehicle braking force control device 1 according to the present embodiment. FIG. 4 is a schematic diagram showing the flow of the working fluid in the first turning control of the vehicle braking force control device 1 according to the present embodiment. In the following description, wheel 110a is a wheel arranged on the rear right side, wheel 110b is a wheel arranged on the front left side, wheel 110c is a wheel arranged on the front right side, and wheel 110d is a wheel arranged on the rear left side.

[0037] When the control device 50 detects that the vehicle 100 is at or below a predetermined vehicle speed set in advance by the vehicle speed detection device 11 and detects that the vehicle 100 is in a turning state by the steering operation sensor 18 indicating the state of the steering 101, the first turning control is executed. The predetermined vehicle speed may be, for example, any value in the range of 5 to 30 km, and is not limited to this range as long as it is a value that can determine that the vehicle is in a low-speed state. Also, whether or not the vehicle is in a turning state may be determined using information different from the information indicating the state of the steering 101, such as directly detecting the state of the wheels. Further, the turning state is not limited to the forward or reverse state of the vehicle.

[0038] In the first turning control, the electric actuator 33 is operated to apply pressure to the working fluid by the hydraulic pressure generating device 12 to increase the pressure, and by controlling the opening and closing states of the first valves 22a to 22d and the second valves 23a to 23d, a braking force difference is generated in the wheels 110a to 110d. When this first turning control is executed, the drive motor 27 is in a stopped state.

[0039] The relationship between the opening and closing states of the first valves 22a to 22d and the second valves 23a to 23d and the braking force applied to the wheels 110a to 110d in the first turning control will be described by taking a right turn as an example. The control device 50 operates the electric actuator 33 to generate hydraulic pressure, and controls the first valves 22a and 22c corresponding to the wheels 110a and 110c, which are the inner wheels of the turn, to the open valve state. Further, the control device 50 controls the first valves 22b and 22d corresponding to the wheels 110b and 110d, which are the outer wheels of the turn, to the closed valve state. Also, in the first turning control, all of the second valves 23a to 23d for sending the working fluid to the reservoirs 25a to 25b are controlled to the closed state.

[0040] When the first valves 22a and 22c are controlled to the open valve state and the first valves 22b and 22d are controlled to the closed valve state, the hydraulic fluid supplied to the friction brakes 20a of the wheel 110a and the friction brakes 20c of the wheel 110c is pressurized, and a braking force (2 Mpa in the example of FIG. 3) is applied to the inner wheels of the turn. Since the hydraulic fluid is not pressurized in the friction brakes 20b and 20d corresponding to the outer wheels of the turn, the braking force becomes small (0 Mpa in the example of FIG. 3). Here, the braking force may mean the actually applied braking force or may mean the relative difference between the outer wheel and the inner wheel of the turn. That is, the difference in braking force may be 2 MPa.

[0041] As described above, in the first turning control executed during low-speed turning, the inner wheels of the turn are pressurized by the electric actuator 33 of the hydraulic pressure generating device 12, which is a slave cylinder, without using the drive motors 27 that drive the pumps 26a to 26b of the behavior stabilizing device 21. In FIGS. 3 and 4, an example of a right turn has been described, but in a left turn, the left and right relationships are reversed. That is, among the first valves 22a to 22d, the first valves 22b and 22d corresponding to the inner wheels of the left turn are controlled to the open valve state, and the first valves 22a and 22c corresponding to the outer wheels of the turn are controlled to the closed valve state.

[0042] Next, with reference to FIGS. 5 and 6, a second turning control that is executed when a braking operation is performed with a force equal to or greater than a predetermined value during a low-speed turn will be described. FIG. 5 is a schematic diagram showing the braking force applied to wheels 110a to 110d by the second turning control of the vehicle braking force control device 1 according to the present embodiment. FIG. 6 is a schematic diagram showing the flow of the working fluid in the second turning control of the vehicle braking force control device 1 according to the present embodiment.

[0043] When the control device 50 detects a braking operation by the driver with a force equal to or greater than a preset operating force during a low-speed turn, it executes the second turning control. The preset operating force is appropriately set theoretically or empirically, for example, in the configuration and design of the braking operation device 10.

[0044] In the second turning control, the electric actuator 33 is operated to apply pressure to the working fluid by the hydraulic pressure generating device 12, and by controlling the opening and closing states of the first valves 22a to 22d and the second valves 23a to 23d, braking forces are generated on all the wheels 110a to 110d. Even when this second turning control is being executed, the drive motor 27 is in a stopped state.

[0045] During the execution of the second turning control, the control device 50 operates the electric actuator 33 to generate hydraulic pressure, controls all of the first valves 22a to 22d to be in an open valve state, and controls all of the second valves 23a to 23d for sending the working fluid to the reservoirs 25a to 25b to be in a closed state. As a result, the working fluid supplied to all the friction brakes 20a to 20d is pressurized, and a braking force (2 Mpa in the example of FIG. 5) is applied to all the wheels 110a to 110d.

[0046] Next, with reference to FIGS. 7 and 8, a third turning control that is executed when a braking operation with a force less than a predetermined value is performed during a low-speed turn will be described. FIG. 7 is a schematic diagram showing the braking force applied to wheels 110a to 110d by the third turning control of the vehicle braking force control device 1 according to the present embodiment. FIG. 8 is a schematic diagram showing the flow of the working fluid in the third turning control of the vehicle braking force control device 1 according to the present embodiment.

[0047] When the control device 50 detects a brake operation with a force less than a preset operation force during a low-speed turn, it executes third turning control. The preset operation force is appropriately set theoretically or empirically, for example, in the configuration and design of the brake operation device 10.

[0048] In the third turning control, the electric actuator 33 is operated to apply pressure to the working fluid by the hydraulic generator 12, and the braking force difference is generated in the wheels 110a to 110d by controlling the opening and closing states of the first valves 22a to 22d and the second valves 23a to 23d. When this third turning control is executed, the drive motor 27 is in a stopped state.

[0049] The relationship between the opening and closing states of the first valves 22a to 22d and the second valves 23a to 23d in the third turning control and the braking force applied to the wheels 110a to 110d will be described by taking a right turn as an example. The control device 50 operates the electric actuator 33 to generate hydraulic pressure, and the first valve 22a and the first valve 22c are controlled to be in an open valve state, while the first valve 22b and the first valve 22d are controlled to be in a closed valve state. Further, the control device 50 controls the second valves 23b and 23d corresponding to the wheels 110b and 110d, which are the outer wheels of the turn, to be in an open valve state, and controls the second valves 23a and 23c corresponding to the wheels 110a and 110c, which are the inner wheels of the turn, to be in a closed valve state.

[0050] When the first valve 22a and the first valve 22c are controlled to be in an open valve state, and the first valve 22b and the first valve 22d are controlled to be in a closed valve state, the working fluid supplied to the friction brakes 20a and 20c corresponding to the inner wheels of the turn is pressurized and a braking force (2 Mpa in the example of FIG. 7) is applied. On the other hand, the working fluid supplied to the friction brakes 20b and 20d corresponding to the outer wheels of the turn is discharged to the reservoirs 25a to 25b and the braking force becomes smaller (0 Mpa in the example of FIG. 7). In FIGS. 7 and 8, an example of a right turn has been described, but in a left turn, the left and right relationships are reversed.

[0051] Next, with reference to FIG. 9, an example of the overall processing flow of the low-speed turning control will be described. FIG. 9 is a flowchart showing an example of the processing flow of the low-speed turning control by the braking force control device for a vehicle according to the present embodiment.

[0052] First, the control device 50 monitors detection values of the vehicle speed detection device 11, the steering operation sensor 18, etc., and determines whether the traveling state of the vehicle 100 is a low-speed turn (step S10). When the traveling state of the vehicle 100 is a low-speed turn, the control device 50 advances the process to step S11 (step S10; Yes), and when it is not a low-speed turn, the process returns and the monitoring continues (step S10; No).

[0053] In step S11, the control device 50 determines whether a brake operation has been performed during a low-speed turn. When no brake operation has been performed, the control device 50 advances the process to step S12 (step S11; No), and when a brake operation has been performed, the control device 50 advances the process to step S13 (step S11; Yes).

[0054] In step S12, the above-described first turning control, which is a pressure control for generating a braking force on the inner turning wheel, is executed. That is, the control device 50 performs operation control of the electric actuator 33, valve opening control of the first valves 22a to 22d corresponding to the inner turning wheel, valve closing control of the first valves 22a to 22d corresponding to the outer turning wheel, and valve closing control of all the second valves 23a to 23d. After the process of step S12, the control device 50 returns the process to step S10.

[0055] In step S13, the control device 50 determines whether the operating force applied to the brake pedal 30 is equal to or greater than a predetermined value or less than the predetermined value based on the detection value of the brake operation sensor 31. When the operating force is equal to or greater than the predetermined value, the control device 50 advances the process to step S14 (step S13; Yes), and when the operating force is less than the predetermined value, the control device 50 advances the process to step S16 (step S13; No).

[0056] In step S14, the above-mentioned second turning control, which is a pressure application control that generates braking forces on all wheels, is executed. That is, the control device 50 executes operation control of the electric actuator 33, valve opening control of all first valves 22a to 22d, and valve closing control of all second valves 23a to 23d. After processing step S14, the control device 50 proceeds to step S15.

[0057] In step S15, the control device 50 determines whether the operating force has become less than a predetermined value. If the operating force has become less than the predetermined value, the control device 50 proceeds to step S16 (step S15; Yes), and if the operating force is not less than the predetermined value, the control device 50 returns to step S10 (step S15; No).

[0058] In step S16, the control device 50 executes the third turning control, which is a pressure control for applying a braking force to the inside turning wheel. That is, the control device 50 executes operation control of the electric actuator 33, valve opening control of all of the first valves 22a to 22d, valve opening control of the second valves 23a to 23d corresponding to the outside turning wheel, and valve closing control of the second valves 23a to 23d corresponding to the inside turning wheel. After processing step S16, the control device 50 returns the process to step S10.

[0059] In the example shown in Figure 9, the turning control is switched. If a brake operation is performed during the first turning control, the turning control is shifted to the second turning control or the third turning control. Conversely, if a brake operation is no longer detected while the second turning control or the third turning control is being executed, the turning control is shifted to the first turning control.

[0060] According to the vehicle braking force control device 1 for applying braking force to the vehicle 100 of this embodiment described above, the following effects are achieved.

[0061] The braking force control device 1 for a vehicle according to this embodiment includes a vehicle speed detection device 11 that detects the vehicle speed of the vehicle 100, a plurality of friction brakes 20a to 20d that are arranged on a plurality of wheels of the vehicle 100 and are driven by the hydraulic pressure of the working fluid, a hydraulic pressure generating device 12 that generates hydraulic pressure in the working fluid by the operation of the electric actuator 33, a behavior stabilizing device 21 that adjusts the hydraulic pressure of the working fluid supplied from the hydraulic pressure generating device 12 and applies the adjusted hydraulic pressure to the plurality of friction brakes 20a to 20d to stabilize the behavior of the vehicle 100, and a control device 50 that controls the operation of the behavior stabilizing device 21 and adjusts the braking force applied to the plurality of wheels 110a to 110d. The behavior stabilizing device 21 includes a plurality of first valves 22a to 22d that control the movement of the working fluid to each of the plurality of friction brakes 20a to 20d, reservoirs 25a to 25b from which the working fluid is discharged from the branch portions of the path 40 of the working fluid between the plurality of first valves 22a to 22d and the friction brakes 20a to 20d, second valves 23a to 23d that are arranged between the plurality of first valves 22a to 22d and the reservoirs 25a to 25b and control the movement of the working fluid to the reservoirs 25a to 25b, pumps 26a to 26b that discharge the working fluid discharged to the reservoirs 25a to 25b by pressurization to the path from the reservoirs 25a to 25b to the hydraulic pressure generating device 12, and drive motors 27 that drive the pumps 26a to 26b. When the vehicle 100 is in a turning state at a vehicle speed below a predetermined vehicle speed, the control device 50 controls the operation of the electric actuator 33 to generate hydraulic pressure by the hydraulic pressure generating device 12, and controls the opening and closing states of the first valves 22a to 22d and the second valves 23a to 23d to execute turning control for applying braking force to the plurality of wheels 110a to 110d. In the turning control, the driving of the drive motor 27 is stopped.

[0062] Thereby, when the vehicle 100 is turning at a low speed, braking force can be applied to the wheels 110a to 110d by the hydraulic pressure generated by the hydraulic pressure generating device 12 without using the drive motors 27 that drive the pumps 26a to 26b, which produce a large operating sound. Therefore, it is possible to improve the commerciality by reducing the operating sound caused by the pressurization of the working fluid while improving the turning performance.

[0063] In this embodiment, in the turning control, the control device 50 generates hydraulic pressure by the hydraulic pressure generating device 12, opens the first valves 22a and 22c (or the first valves 22b and 22d) corresponding to the turning inner ring, and closes the first valves 22b and 22d (or the first valves 22a and 22c) corresponding to the turning outer ring to generate a braking force difference among the plurality of wheels 110a to 110d.

[0064] Thereby, without using the drive motors 27 that drive the pumps 26a to 26b, it is possible to generate a braking force difference between the turning outer ring and the turning inner ring by controlling the opening and closing of the first valves 22a to 22d, and it is possible to achieve both higher turning performance and quietness.

[0065] The vehicle braking force control device 1 of this embodiment includes a brake operation sensor 31 that detects the operation of the brake pedal 30 by the vehicle driver. In the turning control, when the operation of the brake pedal 30 is detected, the control device 50 generates hydraulic pressure by the hydraulic pressure generating device 12 and opens the plurality of first valves 22a to 22d.

[0066] Thereby, even when the operation of the brake pedal 30 is detected during turning control, it is possible to apply a braking force by pressurizing all the wheels 110a to 110d by controlling the opening and closing of the first valves 22a to 22d, and it is possible to realize prompt braking control while reducing the operating noise related to the pressurization of the working fluid.

[0067] When the operating force of the brake pedal 30 is equal to or greater than a predetermined value in the turning control, the control device 50 of this embodiment generates hydraulic pressure by the hydraulic pressure generating device 12 and opens the plurality of first valves 22a to 22d. When the operating force of the brake pedal 30 becomes less than the predetermined value in the turning control, the second valves 23a and 23c (or the second valves 23b and 23d) corresponding to the turning inner ring are closed, and the second valves 23b and 23d (or the second valves 23a and 23c) corresponding to the turning outer ring are opened.

[0068] As a result, when the operating force of the brake pedal 30 becomes less than a predetermined value from a value equal to or greater than the predetermined value during turning control, the hydraulic pressure to the friction brakes 20b and 20d (or the friction brakes 20a and 20c) that apply braking force to the outer turning wheels is reduced. Prompt pressure control and decompression control according to changes in the operation of the brake pedal 30 are realized.

[0069] As described above, the embodiments of the present invention have been described, but the present invention is not limited to the above-described embodiments. Further, the effects described in each embodiment are merely a list of preferable effects, and are not limited to those described in the above embodiments.

[0070] In the above embodiment, the configuration is not limited to switching the turning control. It may be configured to perform only any one of the first turning control, the second turning control, and the third turning control, or may be configured not to shift to other turning controls when the turning control is executed. Thus, the turning control can be changed as appropriate.

Explanation of Signs

[0071] 1 Vehicle braking force control device 11 Vehicle speed detection device 12 Hydraulic pressure generating device 20a~20d Friction brakes 21 Behavior stabilization device 22a~22d First valves 23a~23d Second valves 25a~25b Reservoirs 26a~26b Pumps 27 Drive motor 30 Brake pedal (brake operator) 31 Brake operation sensor (brake operation detection unit) 33 Electric actuator 50 Control device 100 Vehicle 110a~110d Wheels

Claims

1. A vehicle braking force control device that applies a braking force to a vehicle, comprising: a vehicle speed detection device that detects the vehicle speed of the vehicle; a plurality of friction brakes arranged on a plurality of wheels of the vehicle and driven by the hydraulic pressure of a working fluid; a hydraulic pressure generating device that generates hydraulic pressure in the working fluid by the operation of an electric actuator; a behavior stabilizing device that adjusts the hydraulic pressure of the working fluid supplied from the hydraulic pressure generating device and applies the adjusted hydraulic pressure to the plurality of friction brakes to stabilize the behavior of the vehicle; a control device that controls the operation of the behavior stabilizing device and adjusts the braking force applied to the plurality of wheels; a brake operation detection unit that detects an operation of a brake operating element by a driver, and the behavior stabilizing device includes: a plurality of first valves that control the movement of the working fluid to each of the plurality of friction brakes; a reservoir from which the working fluid is discharged from a branch portion of the path of the working fluid between the plurality of first valves and the friction brakes; a second valve disposed between each of the plurality of first valves and the reservoir and controlling the movement of the working fluid to the reservoir; a pump that discharges the working fluid discharged into the reservoir by pressurization to a path from the reservoir to the hydraulic pressure generating device; a drive motor that drives the pump, and the control device: When the vehicle is in a turning state at a vehicle speed equal to or lower than a predetermined vehicle speed, controls the operation of the electric actuator to generate hydraulic pressure by the hydraulic pressure generating device, and controls the opening and closing states of the first valve and the second valve to apply a braking force to the plurality of wheels, and executes turning control; In the turning control, the driving of the drive motor is stopped; While generating hydraulic pressure by the hydraulic pressure generating device, the first valve corresponding to the inner wheel during turning is set to an open valve state, and the first valve corresponding to the outer wheel during turning is controlled to a closed valve state to generate a braking force difference between the plurality of wheels; A vehicle braking force control device that, when an operation of the brake operating element is detected, generates hydraulic pressure by the hydraulic pressure generating device and sets the plurality of first valves to an open valve state.

2. The control device: In the turning control, when the operating force of the brake operating element is equal to or greater than a predetermined value, generates hydraulic pressure by the hydraulic pressure generating device and sets the plurality of first valves to an open valve state. In the turning control, when the operating force of the brake operator becomes less than a predetermined value, the second valve corresponding to the turning inner ring is closed, and the second valve corresponding to the turning outer ring is opened. The vehicle braking force control device according to claim 1.

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