WO2020027068A1

WO2020027068A1 - Brake control device

Info

Publication number: WO2020027068A1
Application number: PCT/JP2019/029708
Authority: WO
Inventors: 和寛中村; 泰浩阿部; 宮崎　直人
Original assignee: 株式会社アドヴィックス
Priority date: 2018-07-30
Filing date: 2019-07-29
Publication date: 2020-02-06
Also published as: JP2020019306A

Abstract

The present invention is a brake control device which is provided with a first braking device 811 that corresponds to first wheels Wfr, Wfl provided on a vehicle and a second braking device 812 that corresponds to second wheels Wrr, Wrl provided on the vehicle, and which applies a braking force on the vehicle by controlling the first braking device 811 and the second braking device 812. The brake control device comprises a preliminary operation control unit 61 that preliminarily, prior to applying the braking force, operates the first braking device 811 and/or the second braking device 812 on the basis of the operating characteristics of both the first braking device 811 and the second braking device 812.

Description

Braking control device

The present invention relates to a braking control device.

In the case where the braking control device is configured to generate a hydraulic braking force, for example, the braking control device includes an actuator that increases the hydraulic pressure (wheel pressure) of the wheel cylinder on the downstream side. The wheel cylinder is provided in the hydraulic braking device of each wheel. An oil passage connected to each wheel cylinder is provided in the actuator. 2. Description of the Related Art Conventionally, in a brake control device, for example, a precharge process of previously reducing a clearance between a brake pad and a brake rotor has been performed in order to improve responsiveness. In the precharge process, the brake fluid is supplied to the wheel cylinder in advance by a common actuator before the start of braking. The precharge processing is described in, for example, JP-A-2006-69495.

JP 2006-69495 A

However, for example, the disc brake device and the drum brake device differ in the amount of brake fluid required for the precharge process, and the responsiveness can be improved only by performing a uniform precharge process on a vehicle equipped with both brake devices. There is a limit to improvement. In particular, in a vehicle that can generate a braking force different from the target of the precharge processing, such as a regenerative braking force, for example, when the braking force of the precharge processing target is added to the braking force of the precharge processing target, insufficient precharge occurs. As a result, the increase in the braking force may temporarily stagnate, giving the driver an uncomfortable feeling.

The present invention has been made in view of such circumstances, and has as its object to provide a braking control device capable of improving responsiveness.

The present invention includes a first braking device corresponding to a first wheel provided in a vehicle, and a second braking device corresponding to a second wheel provided in the vehicle, wherein the first braking device and the second braking device correspond to each other. A braking control device for applying a braking force to the vehicle by controlling a second braking device, wherein prior to the application of the braking force, the operating characteristics of both the first braking device and the second braking device are adjusted. A preliminary operation control unit that preliminarily activates at least one of the first braking device and the second braking device.

According to the present invention, a preliminary operation is performed in consideration of the operation characteristics of each of the braking devices (for example, a precharge amount required until the braking force starts to be generated). As a result, it is possible to perform a selective precharge process more suitable for exhibiting overall responsiveness, rather than performing the precharge process uniformly for a plurality of braking devices. That is, according to the present invention, the responsiveness can be improved.

It is a lineblock diagram of a brake control device of this embodiment. 5 is a time chart for explaining a preliminary operation of the present embodiment. 5 is a time chart for explaining a preliminary operation of the present embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. Each drawing used for explanation is a conceptual diagram, and the shape of each part is not always strict. As shown in FIG. 1, the brake control device 1 according to the present embodiment includes a brake pedal 11, a booster 12, a master cylinder 13, a reservoir 14, a brake switch 15, a stroke sensor 16, an actuator 5, The brake ECU 6, a hydraulic braking device 81, and a regenerative braking device 82 are provided.

The brake pedal 11 is an operating member that can be operated by the driver to brake. The brake switch 15 is a sensor that detects whether or not the brake pedal 11 is depressed (ie, whether or not an operation is performed). The brake switch 15 is also called a brake stop switch. The brake switch 15 outputs a detection signal to the brake ECU 6.

The booster 12 is a vacuum booster that assists the brake operating force by using the intake negative pressure of the engine. The master cylinder 13 is a device that converts the operation force of the brake pedal 11 by the driver into a master pressure and supplies the master pressure to the wheel cylinders 541 to 544 via the actuator 5. The master cylinder 13 includes a first master chamber 13a and a second master chamber 13b that generate a master pressure according to the operation of the brake pedal 11. The master cylinder 13 is configured such that the same hydraulic pressure is formed in the first master chamber 13a and the second master chamber 13b. That is, the first master chamber 13a is formed between the first master piston 13c and the second master piston 13d, and the second master chamber 13b is formed between the second master piston 13d and the bottom of the master cylinder 13. Have been. A first spring 13e is interposed between the first master piston 13c and the second master piston 13d, and a second spring 13f is interposed between the second master piston 13d and the bottom of the master cylinder 13. Have been.

The reservoir 14 is a member for storing the brake fluid and replenishing the master cylinder 13 with the brake fluid. In other words, it is a member that stores the brake fluid, and is connected to the

master chambers

13a and 13b. The

master chambers

13a and 13b communicate with the reservoir 14 in an initial state, and are shut off when the strokes of the

master pistons

13c and 13d become equal to or more than a predetermined value. That is, the

master pistons

13c and 13d are configured to shut off the space between the

master chambers

13a and 13b and the reservoir 14 when the stroke of the brake pedal 11 is equal to or more than the predetermined value. The

master pistons

13c and 13d are mechanically connected to the brake pedal 11 via a booster 12. The movement of the

master pistons

13c and 13d and the movement of the brake pedal 11 are mechanically linked.

The stroke sensor 16 is a sensor that detects the operation amount (stroke) of the brake pedal 11. The stroke sensor 16 outputs a detection signal to the brake ECU 6. In the braking control device 1, an invalid stroke is set for the operation of the brake pedal 11, and the generation of the regenerative braking force is prioritized until the stroke exceeds a predetermined value, and the hydraulic braking force by the master pressure is applied. Is configured not to occur.

The actuator 5 is arranged between the first master chamber 13a and the second master chamber 13b in which the master pressure is generated, and the

wheel cylinders

541, 542, 543, and 544. The actuator 5 and the first master chamber 13a are connected by an oil passage 31, and the actuator 5 and the second master chamber 13b are connected by an oil passage 32. The actuator 5 is a device that adjusts the hydraulic pressure (wheel pressure) of the wheel cylinders 541 to 544 according to an instruction from the brake ECU 6. The actuator 5 executes a pressure control for further increasing the brake fluid from the master pressure, a pressure reduction control for reducing the wheel pressure, and a holding control for holding the wheel pressure in accordance with a command from the brake ECU 6. The actuator 5 can also execute a pressure increase control for supplying the master pressure to the wheel cylinders 541 to 544 as it is. The actuator 5 executes anti-skid control (ABS control), side skid prevention control (ESC control), brake assist control (BA control), and the like based on a command from the brake ECU 6.

Specifically, the actuator 5 includes a hydraulic circuit 5A and an electric motor 90. The hydraulic circuit 5A includes a first piping system 50a and a second piping system 50b. The first piping system 50a is a system that controls the hydraulic pressure (wheel pressure) applied to the front wheel Wfl and the rear wheel Wrr. The second piping system 50b is a system that controls the hydraulic pressure (wheel pressure) applied to the front wheel Wfr and the rear wheel Wrl. In addition, a wheel speed sensor is provided for each wheel W (in some cases, the sign of the wheel is collectively described as “W”, the sign of the front wheel is described as “Wf”, and the code of the rear wheel is collectively described as “Wr”). 73 are provided. In this embodiment, an X pipe is employed.

The first piping system 50a includes a main oil passage A, a differential pressure control valve 51,

holding valves

52 and 53, a pressure reducing oil passage B,

pressure reducing valves

54 and 55, a pressure regulating reservoir 56, a reflux oil passage C , A pump 57, an auxiliary oil passage D, an orifice 58, a damper 59, and a pressure sensor 71. In the description, the term “oil passage” can be replaced with, for example, a hydraulic passage, a flow path, a pipe, a passage, a pipe, or the like.

The main oil passage A is an oil passage connecting the oil passage 32 and the

wheel cylinders

541 and 542. That is, the main oil passage A (and the oil passage 32) connects the master cylinder 13 (second master chamber 13b) and the

wheel cylinders

541 and 542. The differential pressure control valve 51 is an electromagnetic valve that is provided in the main oil passage A and controls the main oil passage A between an open state (instruction pressure = 0) and a differential pressure state (instruction pressure> 0). The differential pressure state can be said to be a throttle state. The differential pressure control valve 51 controls the differential pressure between the hydraulic pressure on the master cylinder 13 side and the hydraulic pressure on the

wheel cylinders

541 and 542 relative to itself according to the command pressure (control current) from the brake ECU 6. I do. That is, the differential pressure control valve 51 is an electromagnetic valve that can adjust the difference in hydraulic pressure between the master cylinder 13 and the wheel cylinders 541 to 544. The differential pressure control valve 51 is a valve capable of controlling the fluid pressure on the wheel cylinders 541 to 544 side higher than the fluid pressure on the

master chambers

13a and 13b side by the command pressure.

The differential pressure control valve 51 is provided with a check valve 51a that permits the flow from the master cylinder 13 side (upstream side) to the wheel cylinders 541 to 544 side (downstream side) and prohibits the reverse flow. . The main oil passage A is branched into two oil passages A1 and A2 at a branch point X on the downstream side of the differential pressure control valve 51 so as to correspond to the

wheel cylinders

541 and 542.

The holding

valves

52 and 53 are electromagnetic valves that are opened and closed according to instructions from the brake ECU 6, and are normally open type electromagnetic valves that are opened (communicated) when not energized. The holding valve 52 is arranged in the oil passage A1, and the holding valve 53 is arranged in the oil passage A2. The holding

valves

52 and 53 are opened in a non-energized state during the pressure increasing control to communicate with the

wheel cylinders

541 and 542 and the branch point X, and are energized and closed when the holding control and the pressure reducing control are performed. And the branch point X are cut off. The holding

valves

52 and 53 may be on / off valves (binary control valves) or linear valves capable of controlling the branch point X side higher than the

wheel cylinders

541 and 542 by the indicated pressure.

The decompression oil passage B connects the pressure regulating reservoir 56 between the holding valve 52 and the wheel cylinder 541 in the oil passage A1, and connects the pressure regulating reservoir 56 between the holding valve 53 and the wheel cylinder 542 in the oil passage A2. Is an oil path that connects The

pressure reducing valves

54 and 55 are electromagnetic valves that open and close according to instructions from the brake ECU 6, and are normally closed type electromagnetic valves that are closed (disconnected) when not energized. The pressure reducing valve 54 is arranged in the pressure reducing oil passage B on the wheel cylinder 541 side. The pressure reducing valve 55 is disposed in the pressure reducing oil passage B on the wheel cylinder 542 side. The pressure-reducing

valves

54 and 55 are energized mainly during pressure-reducing control and become open, and communicate the

wheel cylinders

541 and 542 and the pressure-regulating reservoir 56 via the pressure-reducing oil passage B. The pressure regulation reservoir 56 is a reservoir having a cylinder, a piston, and a biasing member.

The recirculation oil passage C is an oil passage connecting the pressure-reducing oil passage B (or the pressure regulating reservoir 56) and the main oil passage A between the differential pressure control valve 51 and the holding valves 52, 53 (here, the branch point X). It is. The pump 57 is provided in the return oil passage C such that the discharge port is located on the branch point X side and the suction port is located on the pressure regulation reservoir 56 side. The pump 57 is an electric pump driven by the electric motor 90. The pump 57 discharges the brake fluid to a portion of the main oil passage A closer to the

wheel cylinders

541 and 542 than the differential pressure control valve 51 (a branch point X in the present embodiment) via the return oil passage C. Further, the pump 57 pumps the brake fluid in the

wheel cylinders

541 and 542 back to the master cylinder 13 via the

pressure reducing valves

54 and 55 in the open state, for example, during anti-skid control. As described above, the pump 57 is disposed between the master cylinder 13 and the

wheel cylinders

541 and 542, and can discharge the brake fluid in the

wheel cylinders

541 and 542 to the outside of the

wheel cylinders

541 and 542. The orifice portion 58 and the damper portion 59 are pulsation reduction mechanisms for reducing pulsation.

The auxiliary oil passage D is an oil passage that connects the pressure adjusting hole 56a of the pressure adjusting reservoir 56 with the main oil passage A upstream of the differential pressure control valve 51 (or the master cylinder 13). The pressure regulating reservoir 56 is configured such that the valve hole 56b is closed with an increase in the amount of brake fluid flowing into the pressure regulating hole 56a due to an increase in the stroke. A reservoir chamber 56c is formed on the oil passages B and C sides of the valve hole 56b.

By driving the pump 57, the brake fluid in the pressure regulating reservoir 56 or the master cylinder 13 causes a portion (branch point) between the differential pressure control valve 51 and the holding

valves

52 and 53 in the main oil passage A via the return oil passage C. X). Then, the wheel pressure is increased according to the control states of the differential pressure control valve 51 and the holding

valves

52 and 53. As described above, in the actuator 5, pressurization control is performed by driving the pump 57 and controlling various valves. The pressure sensor 71 is a sensor that detects a master pressure. The pressure sensor 71 transmits a detection result to the brake ECU 6.

The second piping system 50b has the same configuration as the first piping system 50a, and corresponds to the main oil passage A, and connects a main oil passage Ab that connects the oil passage 31 with the

wheel cylinders

543 and 544; A differential pressure control valve 91 corresponding to 51, holding

valves

92 and 93 corresponding to the holding

valves

52 and 53, a pressure reducing oil passage Bb corresponding to the pressure reducing oil passage B, and a pressure reducing valve 94 corresponding to the

pressure reducing valves

54 and 55. , 95, a pressure regulating reservoir 96 corresponding to the pressure regulating reservoir 56, a return oil passage Cb corresponding to the return oil passage C, a pump 97 corresponding to the pump 57, and an auxiliary oil passage Db corresponding to the auxiliary oil passage D And an orifice portion 58 a corresponding to the orifice portion 58 and a damper portion 59 a corresponding to the damper portion 59. For the detailed configuration of the second piping system 50b, the description of the first piping system 50a can be referred to, and the description is omitted.

Here, each control state by the brake ECU 6 will be briefly described by taking control of the wheel cylinder 541 as an example. In a state without control, the differential pressure control valve 51 and the holding valve 52 are in the open state, and the pressure reducing valve 54 is in the closed state. As a result, the master pressure is supplied to the wheel cylinder 541. In the pressure reduction control, the holding valve 52 is closed, and the pressure reduction valve 54 is opened. In the holding control, the holding valve 52 and the pressure reducing valve 54 are closed. The holding control can also be executed by closing the pressure reducing valve 54 and closing the differential pressure control valve 51 without closing the holding valve 52. In the pressurization control, the differential pressure control valve 51 is in a differential pressure state (a throttle state), the holding valve 52 is in an open state, the pressure reducing valve 54 is in a closed state, and the pump 57 is driven.

As described above, the brake control device 1 according to the present embodiment is configured such that the

master pistons

13 c and 13 d mechanically connected to the brake pedal 11 and the

master pistons

13 c and 13 d are driven by the operation of the brake pedal 11 to thereby drive the master. A master cylinder 13 for generating a master pressure in the

chambers

13a and 13b, and an actuator 5 for sucking brake fluid in the

master chambers

13a and 13b when increasing the hydraulic braking force and supplying the sucked brake fluid to the wheel cylinders 541 to 544. And a system for applying at least one of a hydraulic braking force and a regenerative braking force to the wheel W of the vehicle.

The brake ECU 6 is an electronic control unit including a CPU, a memory, and the like. Various sensors such as a brake switch 15, a stroke sensor 16, a pressure sensor 71, and a wheel speed sensor 73 are connected to the brake ECU 6 via a communication line (not shown). The brake ECU 6 determines whether the operation of the actuator 5 is necessary based on the detection results of these various sensors. When the brake ECU 6 determines that the operation of the actuator 5 is necessary, the brake ECU 6 calculates a target wheel pressure as a wheel pressure target value for each of the wheel cylinders 541 to 544, and controls the actuator 5. The target wheel pressure corresponds to the target hydraulic braking force. The brake ECU 6 can calculate the master pressure (upstream hydraulic pressure) based on the detection value of the pressure sensor 71 and the control state of the differential pressure control valve 51, and detect the detection value of the pressure sensor 71 and the holding

valves

52 and 53. The wheel pressure (downstream hydraulic pressure) can be calculated based on the control state of the

pressure reducing valves

54 and 55.

Here, the first piping system 50a will be further described. A portion of the oil passage A1 between the holding valve 52 and the wheel cylinder 541 is referred to as a first oil passage 81a, and a portion of the oil passage A2 between the holding valve 53 and the wheel cylinder 542 is referred to as a second oil passage 81b. Name. The pump 57, the motor 90, and the pressure regulating reservoir 56 constitute a hydraulic pressure supply unit 81c that supplies brake fluid to the first oil passage 81a and the second oil passage 81b via the holding

valves

52, 53. I have. The first oil passage 81a and the second oil passage 81b are connected via holding

valves

52 and 53. The holding valve 52 is an electromagnetic valve that is provided in a first oil passage 81a connected to a disc brake device 811 to be described later and holds the brake fluid in the first oil passage 81a. The holding valve 53 is an electromagnetic valve that is provided in a second oil passage 81b connected to a drum brake device 812 described later, and holds the brake fluid in the second oil passage 81b. The second piping system 50b also has the same configuration as the first piping system 50a.

The hydraulic braking device 81 includes a disk brake device (corresponding to a “first braking device” and a “first hydraulic braking device”) 811 provided on each front wheel Wf, and a drum brake provided on each rear wheel Wr. And a device (corresponding to a “second brake device” and a “second hydraulic brake device”) 812. The disc brake device 811 of the first piping system 50a includes a wheel cylinder 541, and the disc brake device 811 of the second piping system 50b includes a wheel cylinder 544. The drum brake device 812 of the first piping system 50a includes a wheel cylinder 542, and the drum brake device 812 of the second piping system 50b includes a wheel cylinder 543.

As described above, the brake control device 1 of the present embodiment corresponds to the disc brake device 811 corresponding to the first wheels Wfr and Wfl provided in the vehicle and the second wheel Wrr and Wrl provided to the vehicle. A drum brake device 812 is provided, and a braking force is applied to the vehicle by controlling the disk brake device 811 and the drum brake device 812.

The regenerative braking device 82 is a device that generates regenerative braking force on the wheels W, and includes a generator, an inverter, a motor, and a hybrid ECU (not shown). The brake ECU 6 performs regenerative cooperative control with the regenerative braking device 82. The regenerative braking device 82 is configured to apply a regenerative braking force to the front wheels or the rear wheels. In the regenerative cooperative control, the target regenerative braking force and the target hydraulic braking force are set such that the total of the regenerative braking force and the hydraulic braking force becomes the target braking force while considering the regeneration efficiency. The change gradient of the target regenerative braking force and the target hydraulic braking force is reflected on the change gradient of the regenerative braking force and the hydraulic braking force as a result. The target braking force (target deceleration) is set according to, for example, a driver's brake operation.

(Precharge processing)
The brake ECU 6 includes a preliminary operation control unit 61 and a cooperative control unit 62 as functions for the precharge process and the cooperative control. The preliminary operation control unit 61 preliminarily activates at least one of the disk brake device 811 and the drum brake device 812 based on the operation characteristics of both the disk brake device 811 and the drum brake device 812 prior to the application of the braking force. It is configured to be. That is, the preliminary operation control unit 61 considers the operating characteristics of the hydraulic braking device for the front wheels Wf and the hydraulic braking device for the rear wheels Wr, and controls at least one of the disc brake device 811 and the drum brake device 812. Perform precharge processing. Since the control related to the precharge process is the same for the first piping system 50a and the second piping system 50b, the first piping system 50a and the

wheel cylinders

541 and 542 will be described, and the second piping system 50b will be described. Omitted.

The operating characteristics of the disc brake device 811 include, for example, the stiffness of the wheel cylinder 541, which is the required fluid amount or the required precharge amount related to the hydraulic pressure until the hydraulic braking force starts to be generated, or the required pressure change amount per unit volume change. This is a characteristic that is determined based on such factors. In the present embodiment, the operation characteristics of the disc brake device 811 are set based on the required precharge amount. In other words, the hydraulic pressure or the amount of fluid required to make the clearance between the brake pad and the brake rotor in the disc brake device 811 substantially zero is considered as the operating characteristic of the disc brake device 811. Similarly, the operation characteristics of the drum brake device 812 are characteristics determined based on, for example, the required precharge amount or the rigidity of the wheel cylinder 542, and are set in the present embodiment based on the required precharge amount. That is, the hydraulic pressure or the amount of fluid required to make the clearance between the brake shoe and the drum in the drum brake device 812 substantially zero is considered as the operation characteristic of the drum brake device 812.

The required precharge amount of the disc brake device 811 is different from the required precharge amount of the drum brake device 812 in both the fluid amount and the fluid pressure. For example, the disc brake device 811 completes the precharge process at 0.1 MPa (clearance # 0), and the drum brake device 812 completes the precharge process at 0.4 MPa (clearance # 0). In the present embodiment, a preliminary operation (precharge processing) is performed in consideration of the magnitude relationship between the required precharge amounts of the two braking devices. In the present embodiment, the precharge process is selectively performed in consideration of the fact that the hydraulic pressure required for completing the precharge differs between the two braking devices.

Here, the braking control device 1 of the present embodiment generates regenerative braking force by the regenerative braking device 82 until a predetermined condition is satisfied, and after the predetermined condition is satisfied, the disc brake device 811 and the drum brake device 812 also perform hydraulic pressure control. It is configured to generate power. The braking control device 1 generates a braking force by the regenerative braking device 82 according to the target braking force, and when the target braking force and the regenerative braking force become equal to or more than a predetermined value, the disc brake device 811 The drum braking device 812 is configured to generate a braking force.

An example of the precharge process according to the present embodiment will be described with reference to FIG. As shown in FIG. 2, as the stroke increases, the target braking force increases, and the target regenerative braking force (regenerative torque command value) also increases so as to satisfy the target braking force only with the regenerative braking force. Immediately after the start of the stroke increase, a preliminary operation, that is, a precharge process is performed on the drum brake device 812 having a large required precharge amount.

Specifically, the preliminary operation control unit 61 drives the hydraulic pressure supply unit 81c, closes the holding valve 52, opens the holding valve 53, and sets the hydraulic pressure (hereinafter, “necessary”) corresponding to the required precharge amount. The hydraulic pressure of the wheel cylinder 542 is increased until the hydraulic pressure increases. When the hydraulic pressure of the wheel cylinder 542 reaches the required hydraulic pressure, the preliminary operation control unit 61 closes the holding valve 53, opens the holding valve 52, and stops the hydraulic pressure supply unit 81c. That is, when the hydraulic pressure of the wheel cylinder 542 reaches the required hydraulic pressure, the preliminary operation control unit 61 executes the holding control on the wheel cylinder 542 (the second oil passage 81b). Unless the pressure reduction control is performed, the

pressure reduction valves

54 and 55 are closed.

When the target braking force and the regenerative braking force reach predetermined values, the invalid stroke ends and a master pressure corresponding to the stroke is generated. At this time, the preliminary operation control unit 61 continues the holding control on the wheel cylinder 542, maintains the closed state of the holding valve 53, and shuts off the wheel cylinder 542 from another oil path. Due to the increase in the master pressure, the pressure in the non-precharge region including the oil passage around the branch point X, the first oil passage 81a, and the wheel cylinder 541 is increased. Then, when the hydraulic pressure in the non-precharge area reaches the holding hydraulic pressure (= required hydraulic pressure) of the wheel cylinder 542, the preliminary operation control unit 61 opens the holding valve 53.

(4) Before the hydraulic pressure in the non-precharged area reaches the holding hydraulic pressure of the wheel cylinder 542, the wheel cylinder 541 exceeds the required hydraulic pressure, and thereafter, the disk brake device 811 generates a hydraulic braking force on the front wheel Wf. Thereafter, when the hydraulic pressure in the non-precharge region (here, the master pressure) reaches the holding hydraulic pressure of the wheel cylinder 542, the preliminary operation control unit 61 opens the holding valve 53. Accordingly, the brake fluid is also supplied to the wheel cylinder 542, and a hydraulic braking force is generated on the rear wheel Wr by the drum brake device 812. In the braking control device 1 of the present embodiment, when the target braking force is equal to or more than a predetermined value, a hydraulic braking force is generated in addition to the regenerative braking force, and the braking force follows the target braking force.

According to the present embodiment, at least one of the two

hydraulic braking devices

811 and 812 preliminarily operates based on the operation characteristics of the two

hydraulic braking devices

811 and 812. Therefore, as in the above example, the precharge process can be selectively executed on the hydraulic braking device 812 having the larger required precharge amount. A braking device that requires a large amount of precharge and requires a relatively large amount of brake fluid in the early stages of increasing wheel pressure is selected according to operating characteristics, rather than being precharged like other types of braking devices By performing the precharge processing in advance, the responsiveness of the hydraulic braking force can be improved as a whole. According to the present embodiment, it is possible to perform a selective (independent) precharge process that is more suitable for exhibiting overall responsiveness than performing a precharge process uniformly for a plurality of braking devices having different operation characteristics. Become. That is, the responsiveness can be improved.

Further, as described in the above example, the preliminary operation control unit 61 controls the holding

valves

52 and 53 and the hydraulic pressure supply unit 81c so that the disc brake device 811 and the drum brake 811 Based on both the required precharge amounts of the device 812, the holding control for holding the brake fluid in at least one of the first oil passage 81a and the second oil passage 81b is executed.

According to this configuration, appropriate and selective precharge processing can be performed on the

hydraulic braking devices

811 and 812 according to their required precharge amounts. That is, the responsiveness can be improved. Further, as in the above-described example, by performing the precharge processing on the drum brake device 812 having a relatively large required precharge amount, a large amount of brake fluid is generated when the drum brake device 812 generates a braking force. Therefore, it is easy to ensure responsiveness, and it is difficult for the pump 57 to suck the brake pedal 11 due to the sudden suction of the brake fluid from the master cylinder 13. Thereby, deterioration of the brake feeling is also suppressed.

In the above example, the preliminary operation control unit 61 executes the holding control on the second oil passage 81b after generating the required hydraulic pressure in the wheel cylinder 542 (closes the holding valve 53), and thereafter, The hydraulic pressure supply unit 81c is operated to perform the pressurization control, the differential pressure control valve 51 is controlled, and the hydraulic pressure of the wheel cylinder 541 is maintained at the required hydraulic pressure while the holding valve 52 is kept open. As described above, the precharge processing may be performed. In this case, while the hydraulic pressure supply unit 81c continues to operate, the holding control is performed for both the

wheel cylinders

541 and 542 to maintain the wheel pressure at the required hydraulic pressure.

Further, as in the above example, the preparatory operation control unit 61 activates the hydraulic pressure supply unit 81c when applying the hydraulic braking force after the execution of the holding control, and the first hydraulic passage 81a and the second hydraulic passage 81b. The fluid pressure of the first fluid passage 81a (low pressure side fluid passage) which is the lower fluid pressure is changed to the fluid pressure of the second fluid passage 81b (high pressure side fluid passage) which is the higher fluid pressure. , The holding control for the second oil passage 81b is continued.

With this configuration, it is possible to suppress the brake fluid from flowing from the second oil passage 81b, which is the high-pressure side oil passage, to the first oil passage 81a, which is the low-pressure side oil passage, and to more reliably use the pre-operation that utilizes each operation characteristic. Charge processing becomes possible. When the wraparound occurs, the fluid amount and hydraulic pressure of the pre-charged brake fluid fluctuate, so that the responsiveness may also fluctuate. Regarding the drum brake device 812, no hydraulic braking force is generated until the holding control is released. However, since the flow path connected to the wheel cylinder 542 is blocked, regardless of the characteristics (eg, rigidity) of the wheel cylinder 542. The pressure in the non-precharged region can be increased. That is, the pressure in the non-precharge region can be efficiently increased, and the responsiveness can be improved.

Here, when the regenerative braking force of the regenerative braking device 82 becomes insufficient before the predetermined condition is satisfied, that is, before the target braking force becomes equal to or more than the predetermined value, the cooperative control unit 62 sets the disc brake device 811 and Of the drum brake devices 812, the braking device with the smaller required precharge amount (here, the disk brake device 811) is configured to generate a braking force.

As shown in FIG. 3, for example, when the regenerative braking force is insufficient after the holding control for the second oil passage 81b is executed, the cooperative control unit 62 activates the hydraulic pressure supply unit 81c and compares the required precharge amount. The pressure of the wheel cylinder 541 of the disc brake device 811 that is not precharged because of its small size and the corresponding holding valve 52 is open is increased. That is, the shortage of the regenerative braking force is compensated only by the braking force of the disk brake device 811 (the front wheel Wf) by the operation of the hydraulic pressure supply unit 81c.

According to this configuration, the insufficient braking force can be secured by simpler control without changing the state of the holding

valves

52 and 53, and malfunctions and the like can be suppressed. In addition, responsiveness can be easily ensured by securing the insufficient braking force by the braking device having a small required precharge amount.

Note that the braking device that is controlled by the cooperative control unit 62 and that secures the insufficient braking force corresponds to a braking device that has a higher rigidity of the

wheel cylinders

541 and 542 that is a pressure change amount required for a unit volume change. The braking device may be determined to be the braking device in which the holding

valves

52 and 53 are open, or the braking device provided on the front wheel Wf when the front wheel Wf and the rear wheel Wr can be selected. When the rigidity is high, the hydraulic pressure increases with a small amount of liquid, and the responsiveness increases. Further, in the braking device in which the corresponding holding

valves

52 and 53 are open, the control can be simplified as described above. Further, the braking force of the front wheel Wf has a greater effect on the overall braking force than the braking force of the rear wheel Wr, and the responsiveness is improved. In the present embodiment, the rigidity of the wheel cylinder 541 is relatively high.

When the emergency braking is detected, the preliminary operation control unit 61 opens the holding

valves

52 and 53 regardless of whether or not the holding control is performed, or the front wheel that has a relatively large effect on the overall braking force. The holding valve 52 corresponding to Wf is opened. Whether or not the emergency braking is performed is determined based on, for example, whether or not the increasing gradient of the stroke is equal to or greater than a predetermined gradient. When the increase gradient of the stroke is equal to or greater than the predetermined gradient, the preliminary operation control unit 61 determines that the brake operation is emergency braking and detects the emergency braking. At the time of emergency braking, ignoring the continuation conditions of the holding control as in the above example, ignoring the influence on the brake feeling caused by the spillage of the brake fluid and the suction of the brake pedal 11, simplifies the control. Therefore, responsiveness is given the highest priority. As a result, the braking control according to the situation becomes possible. In the present embodiment, at least one of the holding

valves

52 and 53 is provided corresponding to the front wheel Wf of the vehicle, and when the preliminary operation control unit 61 detects the emergency braking, regardless of whether the holding control is performed or not. At least one of the holding

valves

52 and 53 corresponding to the front wheel Wf is opened.

According to the present embodiment, as shown in FIGS. 2 and 3, when a braking force (a hydraulic braking force) to be precharged is applied to a braking force (a regenerative braking force) that is not to be precharged. The stagnation time of the braking force increase can be reduced, and the braking force can smoothly follow the target braking force. Thus, it is possible to prevent the driver from feeling uncomfortable when the braking force is added. Further, according to the present embodiment, it is possible to recover the energy due to the regenerative braking force to the maximum value while suppressing the driver from feeling uncomfortable, which is preferable in terms of energy efficiency. Note that the transition of each braking force and the transition of each wheel pressure in FIGS. 2 and 3 can be regarded as the transition of the target value in the control.

<Others>
The present invention is not limited to the above embodiment. For example, each brake device corresponding to a wheel is not limited to a hydraulic brake device, and may be an electric brake device. The third braking device is not limited to the regenerative braking device, and may be, for example, an electric braking device. That is, the third braking force is not limited to the regenerative braking force. The electric brake device is a device that generates a braking force by pressing a brake pad against a brake rotor by, for example, an electric direct acting type. The operation characteristics of the braking device are not limited to the required precharge amount and the rigidity of the wheel cylinder, but may be, for example, a structural hysteresis characteristic, a play amount (ineffective operation amount) in the electric brake device, and the like. Further, according to the present invention, even if each braking device is the same type of device, if the operation characteristics are structurally different, it is possible to perform a precharge process suitable therefor. In addition, the precharge processing of the present embodiment can be said to be a play reduction processing for reducing clearance. Further, the present invention can be applied to the technology of automatic driving and automatic braking.

Claims

A first braking device corresponding to a first wheel provided in the vehicle; and a second braking device corresponding to a second wheel provided in the vehicle, wherein the first braking device and the second braking device are provided. A braking control device that applies a braking force to the vehicle by controlling
Prior to the application of the braking force, a preliminary operation of preliminarily operating at least one of the first braking device and the second braking device based on the operating characteristics of both the first braking device and the second braking device A braking control device including an operation control unit.
A first holding valve that is provided in a first oil passage connected to a first hydraulic braking device as the first braking device and that holds brake fluid in the first oil passage;
A second holding valve that is provided in a second oil passage connected to a second hydraulic braking device as the second braking device and that holds brake fluid in the second oil passage;
A hydraulic pressure supply unit that supplies brake fluid to the first oil passage and the second oil passage via the first holding valve and the second holding valve;
With
The preliminary operation control unit controls the first holding valve, the second holding valve, and the hydraulic pressure supply unit, so that, prior to the application of the hydraulic braking force, the first hydraulic braking device and the At least one of the first oil passage and the second oil passage is based on a required fluid amount or a required precharge amount related to the hydraulic pressure until the hydraulic braking force for both of the two hydraulic braking devices starts to be generated. The brake control device according to claim 1, wherein the brake control device executes a holding control for holding the brake fluid.
The first oil passage and the second oil passage are connected via the first holding valve and the second holding valve,
The preparatory operation control unit activates the hydraulic pressure supply unit when the hydraulic braking force is applied after the execution of the holding control, and selects the lower hydraulic pressure of the first hydraulic passage and the second hydraulic passage. The holding control for the high-pressure side oil passage is continued until the hydraulic pressure of the low-pressure side oil passage that is the oil passage follows the hydraulic pressure of the high-pressure side oil passage that is the higher oil pressure. A braking control device according to claim 1.
At least one of the first holding valve and the second holding valve is provided corresponding to a front wheel of the vehicle,
When detecting the emergency braking, the preliminary operation control unit opens at least one of the first holding valve and the second holding valve corresponding to the front wheel, regardless of whether the holding control is performed. The braking control device according to claim 2.