Electric control device

Abstract

To quickly accumulate pressure to an accumulator by using an electric cylinder in an electric control device in which a selector valve is not arranged between the electric cylinder and a wheel cylinder.SOLUTION: A control part (10) of an electric control device (1) switches each of an inter-cylinder channel, a first pressure accumulation channel and a second pressure accumulation channel to a cut-off state after making a first electric cylinder (A1) and a second electric cylinder (A2) to a non-operation state, switches the first pressure accumulation channel to a communication state, drives the first electric cylinder (A1) to accumulate fluid pressure in an accumulator (13), switches the first pressure accumulation channel to a cut-off state, equilibrating fluid pressure of the inter-cylinder channel by switching the inter-cylinder channel to a communication state, switches the inter-cylinder channel to a cut-off state, switches the second pressure accumulation channel to a communication state, and drives the second electric cylinder (A2) to accumulate the fluid pressure in the accumulator (13).SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to an electric control device. [Background technology]

[0002] Patent Document 1 discloses a brake control device in which an accumulator is fluidly connected to a wheel cylinder via an on-off valve, and a pressurizing unit driven by an electric motor is fluidly connected to the wheel cylinder via a switching valve. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2018-12432 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the brake control device disclosed in Patent Document 1, a changeover valve is disposed between the pressurizing unit (hereinafter, electric cylinder) and the wheel cylinder, which raises concerns about reduced responsiveness during braking. In response to this concern, if the changeover valve between the electric cylinder and the wheel cylinder is eliminated, brake fluid is consumed in the wheel cylinder when pressure is accumulated in the accumulator, which may prevent pressure from being accumulated in the accumulator quickly. One aspect of the present disclosure aims to quickly accumulate pressure in an accumulator using an electric cylinder in an electric control device in which a switching valve is not disposed between the electric cylinder and a wheel cylinder. [Means for solving the problem]

[0005] In order to solve the above problems, an electric control device according to one aspect of the present disclosure includes a first electric cylinder connected to a first wheel cylinder provided on a first wheel of a vehicle and discharging brake fluid in response to driving of a first electric motor to generate hydraulic pressure, a second electric cylinder connected to a second wheel cylinder provided on a second wheel different from the first wheel of the vehicle and discharging brake fluid in response to driving of a second electric motor different from the first electric motor to generate hydraulic pressure, an accumulator into which the brake fluid discharged from the first electric cylinder and the second electric cylinder flows to accumulate the hydraulic pressure, and a cylinder-to-cylinder flow path between the first electric cylinder and the second electric cylinder, a first accumulation flow path between the first electric cylinder and the accumulator, and a second accumulation flow path between the second electric cylinder and the accumulator, a control unit that executes a first process of switching each of the inter-cylinder flow paths, the first accumulator flow path, and the second accumulator flow path to a blocked state after bringing the first electric cylinder and the second electric cylinder into a deactivated state, a second process of switching the first accumulator flow path to a connected state and driving the first electric cylinder to accumulate hydraulic pressure in the accumulator, a third process of switching the first accumulator flow path to a blocked state and switching the inter-cylinder flow paths to a connected state to balance the hydraulic pressures in the inter-cylinder flow paths, and a fourth process of switching the inter-cylinder flow paths to the blocked state, the second accumulator flow path to a connected state, and driving the second electric cylinder to accumulate hydraulic pressure in the accumulator. Effect of the Invention

[0006] According to one aspect of the present disclosure, in an electric control device in which a switching valve is not disposed between an electric cylinder and a wheel cylinder, pressure can be quickly accumulated in an accumulator using the electric cylinder. [Brief description of the drawings]

[0007] [Figure 1]1 is a schematic configuration diagram of a braking system of a vehicle equipped with an electric control device according to an embodiment of the present disclosure. [Diagram 2] 10 is a flowchart showing a flow of pressure accumulation control while braking force is maintained. [Diagram 3] 13 is a flowchart showing the flow of a retention control process. [Figure 4] FIG. 4 is a diagram showing an example of the relationship between fluid volume and fluid pressure in a wheel cylinder. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Fig. 1 is a schematic diagram of a braking system of a vehicle equipped with an electric control device according to an embodiment of the present disclosure. The vehicle shown in Fig. 1 is equipped with wheels W1 and W2. The wheels W1 and W2 are provided with calipers equipped with wheel cylinders WC1 and WC2, respectively. In Fig. 1, the wheels W1 and W2 are the left front wheel FL and the right front wheel FR of the vehicle, respectively. In the following, it is assumed that an electric parking brake is provided on the rear wheels of the vehicle.

[0009] The vehicle shown in FIG. 1 includes an electric control device 1 according to an embodiment of the present disclosure, a master cylinder 20, a brake pedal 21, a reservoir tank 22, a stroke sensor 23, a stroke simulator 30, and sensors SE1-SE3. The reservoir tank 22 stores brake fluid.

[0010] The electric control device 1 includes electric cylinders A1 and A2, a control unit 10, a storage unit 11, a switching unit 12, and an accumulator 13. The electric cylinders A1 and A2 are an example of a first electric cylinder and a second electric cylinder, and correspond one-to-one to the wheel cylinders WC1 and WC2, respectively. The electric cylinders A1 and A2 have a cylinder C, a piston P, an electric motor M, and a rotation angle sensor R. The electric motor M of the electric cylinders A1 and A2 is an example of a first electric motor and a second electric motor, respectively. Inside the cylinder C of the electric cylinders A1 and A2, a fluid chamber is partitioned by the piston P. A maximum of V1 of brake fluid can be introduced into the fluid chamber of the cylinder C. V1 is, for example, 16 cc. The piston P moves linearly by being driven by the electric motor M. The piston P moves linearly in a direction narrowing the fluid chamber of the cylinder C of the electric cylinders A1 and A2, thereby discharging the brake fluid from the fluid chamber. Hereinafter, the position of the piston P where the fluid chamber of the cylinder C is widest is referred to as the first position of the piston P, and the position of the piston P where the fluid chamber of the cylinder C is narrowest is referred to as the second position of the piston P. In the wheels W1 and W2, a braking force is generated by a friction member (not shown) being pressed against a rotating member that rotates integrally with the wheels W1 and W2 by the hydraulic pressure PA of the wheel cylinders WC1 and WC2.

[0011] The control unit 10 is, for example, a CPU (Central Processing Unit). The control unit 10 controls the electric cylinders A1 and A2 and the switching unit 12 by reading and executing a program stored in the storage unit 11. The storage unit 11 includes a storage medium such as a hard disk drive (HDD) or a solid state drive (SSD). The storage unit 11 also includes a temporary storage medium such as a random access memory (RAM) that the control unit 10 uses as a workspace.

[0012] The switching unit 12 has a master cut valve VL1, an accumulator valve VL2, communication valves VL3 and VL4, and a simulator cut valve VL5. The switching unit 12 is provided in a hydraulic circuit to which the accumulator 13, the master cylinder 20, the stroke simulator 30, and the electric cylinders A1 and A2 are fluidly connected. The hydraulic circuit includes an inter-cylinder flow path between the electric cylinders A1 and A2, a first accumulator flow path between the electric cylinder A1 and the accumulator 13, a second accumulator flow path between the electric cylinder A2 and the accumulator 13, reservoir flow paths between the reservoir tank 22 and each of the electric cylinders A1 and A2, and a flow path between the stroke simulator 30 and the master cylinder 20. The accumulator 13 accumulates the hydraulic pressure of the brake fluid.

[0013] 1, the reservoir flow path branches at a branch point BP1 into a flow path between the reservoir tank 22 and the electric cylinder A1 and a flow path between the reservoir tank 22 and the electric cylinder A2. That is, the flow path between the reservoir tank 22 and the electric cylinder A1 includes a flow path between the reservoir tank 22 and the branch point BP1 and a flow path between the branch point BP1 and the electric cylinder A1. The flow path between the reservoir tank 22 and the electric cylinder A2 includes a flow path between the reservoir tank 22 and the branch point BP1 and a flow path between the branch point BP1 and the electric cylinder A2. The inter-cylinder flow paths include a flow path between the branch point BP1 and the electric cylinder A1 and a flow path between the branch point BP1 and the electric cylinder A2.

[0014] The master cylinder 20 is disposed in a flow path between the reservoir tank 22 and the branch point BP1. The master cut valve VL1 is an electromagnetic valve and disposed in the flow path between the master cylinder 20 and the branch point BP1. The master cut valve VL1 switches the flow path between the master cylinder 20 and the branch point BP1 between a connected state and a cut-off state. The communication valves VL3 and VL4 are solenoid valves. The communication valve VL3 is disposed in the flow path between the electric cylinder A1 and the branch point BP1, and switches the flow path between a connected state and a cutoff state. The communication valve VL4 is disposed in the flow path between the electric cylinder A2 and the branch point BP1, and switches the flow path between a connected state and a cutoff state. When the master cut valve VL1 and the communication valve VL3 are in communication with each other and the piston P of the electric cylinder A1 is located at the first position, brake fluid can be supplied from the reservoir tank 22 to the fluid chamber of the electric cylinder A1. When the master cut valve VL1 and the communication valve VL4 are in communication with each other and the piston P of the electric cylinder A2 is located at the first position, brake fluid can be supplied from the reservoir tank 22 to the fluid chamber of the electric cylinder A2.

[0015] The flow path between the master cylinder 20 and the branch point BP1 has a branch point BP2. The first accumulation flow paths between each of the electric cylinders A1 and A2 and the accumulator 13 include a flow path between each of the electric cylinders A1 and A2 and the branch point BP2, as well as a flow path between the branch point BP2 and the accumulator 13. The accumulator valve VL2 is a solenoid valve that is disposed in a flow path between the branch point BP2 and the accumulator 13, and switches the flow path between a connected state and a cut-off state. The simulator cut valve VL5 is disposed in a flow passage between the stroke simulator 30 and the master cylinder 20, and switches the flow passage between a connected state and a cutoff state.

[0016] The sensor SE1 detects the brake fluid pressure in the passage between the master cylinder 20 and the master cut valve VL1. The sensor SE2 detects the brake fluid pressure in the passage between the wheel cylinder WC1 and the communication valve VL3. The sensor SE3 detects the brake fluid pressure in the passage between the wheel cylinder WC2 and the communication valve VL4. The sensors SE1-SE3 may also function as temperature sensors. For example, the sensors SE2 and SE3 may further detect the temperatures of the electric cylinders A1 and A2. The control unit 10 can obtain the detection results of the sensors SE1-SE3.

[0017] The control unit 10 executes a holding control process for holding the braking force applied to the vehicle by executing a program stored in the storage unit 11. The holding control process includes a first holding control, a second holding control, and a pressure accumulation control, the details of which will be described later.

[0018] In the first hold control, the control unit 10 switches the communication valves VL3 and VL4 to a cut-off state, energizes the electric motor M of the electric cylinder A1, and stops energization of the electric motor M of the electric cylinder A2. The control unit 10 drives the electric cylinder A1 to discharge brake fluid to the wheel cylinder WC1, and increases the hydraulic pressure PA of the wheel cylinder WC1 to a predetermined value Pth. The electric cylinder A2 releases heat while the drive is stopped, thereby decreasing the temperature. The predetermined value Pth is, for example, 10 MPa.

[0019] In the second hold control, the control unit 10 switches the communication valves VL3 and VL4 to a cut-off state, energizes the electric motor M of the electric cylinder A2, and stops energization of the electric motor M of the electric cylinder A1. The control unit 10 drives the electric cylinder A2 to discharge brake fluid to the wheel cylinder WC2, and increases the hydraulic pressure PA of the wheel cylinder WC2 to a predetermined value Pth. The temperature of the electric cylinder A1 decreases as it dissipates heat while the drive is stopped.

[0020] The amount of brake fluid discharged from the electric cylinders A1 and A2 to the wheel cylinders WC1 and WC2 in order to increase the hydraulic pressure PA of the wheel cylinders WC1 and WC2 to a predetermined value Pth is defined as V2. When the hydraulic pressure PA of the wheel cylinders WC1 and WC2 has increased to the predetermined value Pth, brake fluid remains in the hydraulic chambers of the cylinders C of the electric cylinders A1 and A2.

[0021] In the pressure accumulation control, after the hydraulic pressure PA of the wheel cylinders WC1 and WC2 increases to a predetermined value Pth in the first hold control and the second hold control, the control unit 10 accumulates pressure in the accumulator 13 using the brake fluid remaining in the hydraulic chambers of the cylinders C of the electric cylinders A1 and A2.

[0022] For example, if the amount of brake fluid in the fluid chamber of cylinder C of electric cylinder A1 is 16 cc when piston P of electric cylinder A1 is in the first position, and the amount of fluid in wheel cylinder WC1 needs to be increased to 12.5 cc to set the fluid pressure PA of wheel cylinder WC1 to 10.0 MPa, then 3.5 cc of brake fluid (16 cc minus 12.5 cc) is used for accumulation.

[0023] Fig. 2 is a flow chart showing the flow of pressure accumulation control while the braking force is maintained. The control unit 10 repeatedly executes the process of Fig. 2, and once the process of Fig. 2 is completed, starts the process of the next cycle. Immediately after the vehicle ignition switch is turned on, the control unit 10 executes a process of deactivating the electric cylinders A1 and A2 and switching the inter-cylinder flow paths, the reservoir flow path, the first accumulator flow path, and the second accumulator flow path to the cut-off state. This process is an example of the first process and the seventh process. In this process, the control unit 10, for example, deactivates the electric cylinders A1 and A2 and switches the master cut valve VL1, the accumulator valve VL2, the communication valves VL3 and VL4, and the simulator cut valve VL5 to the cut-off state. At this time, the fluid volume in the wheel cylinders WC1 and WC2 is assumed to be 0 cc.

[0024] In S100, the control unit 10 determines whether or not to maintain the braking force applied to the vehicle. For example, when the parking brake is applied or the brake pedal 21 is depressed by a predetermined amount or more, the control unit 10 determines to maintain the braking force applied to the vehicle (S100: YES), changes the master cut valve VL1 to a shutoff state (S200), and executes the maintenance control process shown in Fig. 3. When the parking brake is not applied and the brake pedal 21 is not depressed by a predetermined amount or more, the control unit 10 determines not to maintain the braking force applied to the vehicle (S100: NO), ends the process of the current cycle, and starts the process of the next cycle.

[0025] 3 is a flowchart showing the flow of the hold control process. In the following, it is assumed that at the start of the hold control process, the control unit 10 selects and executes the first hold control from the first hold control and the second hold control.

[0026] In S301, the control unit 10 linearly moves the piston P of the electric cylinder A1 in a direction from the first position to the second position to increase the hydraulic pressure PA of the wheel cylinder WC1. The process executed by the control unit 10 in S301 is an example of a fifth process. In S302, the control unit 10 determines whether the hydraulic pressure PA in the wheel cylinder WC1 is equal to or greater than a predetermined value Pth. The hydraulic pressure PA in the wheel cylinder WC1 is detected by, for example, a sensor SE2. If the hydraulic pressure PA in the wheel cylinder WC1 is smaller than the predetermined value Pth (S302: NO), the control unit 10 ends the processing of the current cycle and starts the processing shown in FIG. 2 for the next cycle.

[0027] When the hydraulic pressure PA of the wheel cylinder WC1 becomes equal to or higher than the predetermined value Pth (S302: YES), the control unit 10 switches the communication valve VL3 and the accumulator valve VL2 to a communication state to switch the first pressure accumulation flow path to a communication state, and starts accumulating hydraulic pressure in the accumulator 13 (S303). The control unit 10 further drives the electric cylinder A1 and executes a process of accumulating hydraulic pressure in the accumulator 13. This process is an example of the second process and the sixth process. In the next step S304, the control unit 10 determines whether the piston P of the electric cylinder A1 has reached the second position. If the piston P of the electric cylinder A1 has not reached the second position (S304: NO), the control unit 10 ends the processing of the current cycle and starts the processing of the next cycle shown in Fig. 2. If the piston P of the electric cylinder A1 has reached the second position (S304: YES), the control unit 10 switches the accumulator valve VL2 to a shutoff state and stops the accumulation of pressure by the accumulator 13 (S305).

[0028] In S306, the control unit 10 linearly moves the piston P of the electric cylinder A1 in a direction from the second position toward the first position. In the next step S307, the control unit 10 brings the communication valves VL3 and VL4 into communication. This releases the hydraulic pressure PA in the wheel cylinder WC1. At this time, the hydraulic pressure in the inter-cylinder flow path is balanced at a hydraulic pressure higher than when the electric cylinders A1 and A2 are in a non-operating state. The process executed by the control unit 10 in S307 is an example of a third process.

[0029] Fig. 4 is a diagram showing an example of the relationship between the fluid volume and the fluid pressure in the wheel cylinder. The relationship between the fluid volume and the fluid pressure PA in the wheel cylinder WC1 changes depending on the driving state of the electric cylinder A1, etc. Fig. 4 shows the relationship between the fluid volume and the fluid pressure PA in the balanced wheel cylinder WC1 when the electric cylinder A1, etc. are stopped.

[0030] For example, if the fluid volume in the wheel cylinders WC1 and WC2 is 0 cc immediately after the vehicle ignition switch is turned on and the electric cylinders A1 and A2 are in a non-operating state, the balanced fluid pressure PA in the wheel cylinders WC1 and WC2 is 0 MPa.

[0031] When the piston P of the electric cylinder A1 moves linearly from the first position to the second position, if the hydraulic pressure PA of the wheel cylinder WC1 is to be 10.0 MPa, it is necessary to increase the hydraulic volume of the wheel cylinder WC1 to 12.5 cc. In S307 of FIG. 3, when the communication valve VL4 is opened, a part of the brake hydraulic fluid in the wheel cylinder WC1 flows into the wheel cylinder WC2. When the brake hydraulic fluid is balanced in a state where 6.25 cc, which is half of the 12.5 cc of the brake hydraulic fluid in the wheel cylinder WC1, flows into the wheel cylinder WC2, as shown in FIG. 4, the hydraulic pressure PA of the wheel cylinders WC1 and WC2 drops to 1.00 MPa. This hydraulic pressure is higher than the hydraulic pressure PA (0 MPa in the above example) of the wheel cylinders WC1 and WC2 balanced when the electric cylinders A1 and A2 are in a non-operated state.

[0032] In S308 in FIG. 3, the control unit 10 switches from the first hold control to the second hold control, and changes the communication valve VL4 to the closed state. In the next S309, the control unit 10 opens the master cut valve VL1 to supply brake fluid to cylinder C of the electric cylinder A1, ends the process of the current cycle, and starts the process of the next cycle shown in FIG.

[0033] In the subsequent second hold control, in S301, the control unit 10 linearly moves the piston P of the electric cylinder A2 in a direction from the first position to the second position to increase the hydraulic pressure PA of the wheel cylinder WC2. This process is an example of a fifth process.

[0034] In S302, the control unit 10 determines whether the hydraulic pressure PA in the wheel cylinder WC2 is equal to or greater than a predetermined value Pth. When the hydraulic pressure PA in the wheel cylinder WC2 is equal to or greater than the predetermined value Pth (S302: YES), the control unit 10 switches the communication valve VL4 and the accumulator valve VL2 to a communication state to switch the second accumulation flow path to a communication state, and starts accumulating hydraulic pressure in the accumulator 13 (S303). The control unit 10 further drives the electric cylinder A2, and executes a process of accumulating hydraulic pressure in the accumulator 13. This process is an example of the fourth process and the sixth process.

[0035] The amount V2 of brake fluid discharged from the electric cylinder A2 to the wheel cylinder WC2 until the hydraulic pressure PA of the wheel cylinder WC2 reaches the predetermined value Pth can be reduced by the amount of brake fluid that flowed from the wheel cylinder WC1 to the wheel cylinder WC2 in the above S307. In other words, the amount of brake fluid used for pressure accumulation can be increased by the amount of brake fluid that flowed from the wheel cylinder WC1 to the wheel cylinder WC2 in the above S307.

[0036] For example, in order to set the hydraulic pressure PA in wheel cylinder WC2 to 10.0 MPa, it is necessary to increase the amount of brake fluid in wheel cylinder WC2 to 12.5 cc, and the wheel cylinder WC2 is equilibrated with 6.25 cc of brake fluid flowing therein in S307. In this case, by discharging 6.25 cc of brake fluid from electric cylinder A2 to wheel cylinder WC2 and increasing the amount of fluid in wheel cylinder WC2 to 12.5 cc, the hydraulic pressure PA in wheel cylinder WC2 can be set to 10.0 MPa. In the case where a maximum of 16 cc of brake fluid can be introduced into the fluid chamber of cylinder C of electric cylinder A2, the 9.75 cc of brake fluid remaining in cylinder C of electric cylinder A2 can be used for pressure accumulation.

[0037] When the second hold control is being executed, in S307, the control unit 10 brings the communication valves VL3 and VL4 into a communication state, thereby releasing the hydraulic pressure PA in the wheel cylinder WC2. In S308, the control unit 10 switches from the second hold control to the first hold control, and brings the communication valve VL3 into the closed state. In the next S309, the control unit 10 opens the master cut valve VL1 to supply brake fluid to cylinder C of the electric cylinder A2, ends the process of the current cycle, and starts the process of the next cycle shown in FIG. During the second and subsequent first hold control periods, the brake fluid used for pressure accumulation can be increased by the amount that flowed from wheel cylinder WC2 to wheel cylinder WC1 in S307.

[0038] [Modifications] In the above embodiment, the control unit 10 selects and executes the first hold control out of the first hold control and the second hold control at the start of the hold control process shown in Fig. 3. However, the control unit 10 may select the second hold control at the start of the hold control process.

[0039] In the above embodiment, the switching unit 12 has the master cut valve VL1, the accumulator valve VL2, the communication valves VL3 and VL4, and the simulator cut valve VL5. However, the components included in the switching unit 12 are not limited to these. For example, an electric cylinder corresponding to a wheel cylinder provided on a rear wheel of the vehicle may be fluidly connected to the hydraulic circuit in which the switching unit 12 is provided. The switching unit 12 may include a solenoid valve provided in a flow path between the accumulator 13 and the electric cylinder corresponding to the wheel cylinder provided on the rear wheel of the vehicle.

[0040] In the above embodiment, in S301 of Fig. 3, the control unit 10 increases the hydraulic pressure PA in the wheel cylinder WC1 or WC2 by linearly moving the piston P of the electric cylinder A1 or A2 in a direction from the first position to the second position. However, the method of increasing the hydraulic pressure PA in the wheel cylinder WC1 or WC2 is not limited to pressurization by the electric cylinder A1 or A2. For example, the control unit 10 may increase the hydraulic pressure PA in the wheel cylinder WC1 or WC2 by discharging brake fluid that has been previously stored in the accumulator 13.

[0041] The accumulator valve VL2 may have multiple solenoid valves according to the flow rate of the brake fluid in the connected state. The amount of brake fluid flowing through the accumulator valve VL2 in the connected state and the hydraulic pressure of the brake fluid are inversely proportional to each other. The control unit 10 may switch between multiple solenoid valves according to the hydraulic pressure to be accumulated in the accumulator 13 and the amount of brake fluid to be pushed into the accumulator 13.

[0042] 〔summary〕 An electric control device according to one aspect of the present disclosure includes a first electric cylinder connected to a first wheel cylinder provided on a first wheel of a vehicle and discharging brake fluid in response to driving of a first electric motor to generate hydraulic pressure, a second electric cylinder connected to a second wheel cylinder provided on a second wheel different from the first wheel of the vehicle and discharging brake fluid in response to driving of a second electric motor different from the first electric motor to generate hydraulic pressure, an accumulator into which brake fluid discharged from the first electric cylinder and the second electric cylinder flows to accumulate the hydraulic pressure, and a flow path between the first electric cylinder and the second electric cylinder, a first accumulation flow path between the first electric cylinder and the accumulator, and a second accumulation flow path between the second electric cylinder and the accumulator, each of which is switched between a connected state and a blocked state. a control unit that executes a first process of switching each of the inter-cylinder flow paths, the first accumulator flow path, and the second accumulator flow path to a blocked state after putting the first electric cylinder and the second electric cylinder in a deactivated state, a second process of switching the first accumulator flow path to a connected state and driving the first electric cylinder to accumulate hydraulic pressure in the accumulator, a third process of switching the first accumulator flow path to a blocked state and switching the inter-cylinder flow paths to a connected state to balance the hydraulic pressures in the inter-cylinder flow paths, and a fourth process of switching the inter-cylinder flow paths to the blocked state, the second accumulator flow path to a connected state, and driving the second electric cylinder to accumulate hydraulic pressure in the accumulator. In the present disclosure, after the first electric cylinder accumulates pressure in the accumulator, the control unit shuts off the master cut valve and the accumulator valve and opens the two communication valves. This releases the hydraulic pressure in the wheel cylinder corresponding to the first electric cylinder, and the brake fluid in the wheel cylinder corresponding to the first electric cylinder flows into the wheel cylinder corresponding to the second electric cylinder. The wheel cylinder corresponding to the second electric cylinder is pre-pressurized by the brake fluid flowing in from the wheel cylinder corresponding to the first electric cylinder, so that a high hydraulic pressure can be generated from the start of pressurization by the second electric cylinder. Therefore, pressure can be quickly accumulated in the accumulator using the electric cylinder.

[0043] In an electric control device according to one embodiment of the present disclosure, after the non-operated state and before switching the first pressure accumulator flow path to a connected state, the control unit executes a fifth process of driving the first electric cylinder to increase the hydraulic pressure in the wheel cylinder corresponding to the first electric cylinder to a predetermined value, and when the first pressure accumulator flow path is switched to the connected state following the fifth process, the control unit executes a sixth process of further driving the first electric cylinder to accumulate hydraulic pressure in the accumulator. In the present disclosure, the control unit increases the hydraulic pressure in the wheel cylinder corresponding to the first electric cylinder to a predetermined value before switching the flow path between the first electric cylinder and the accumulator to a communication state. Then, the control unit pressurizes the accumulator using the surplus power of the first electric cylinder. This allows the pressure accumulation to be performed by efficiently using the pressurizing capacity of the first electric cylinder.

[0044] In an electric control device according to one embodiment of the present disclosure, the switching unit further switches a reservoir flow path between each of the first electric cylinder and the second electric cylinder and a reservoir tank that stores brake fluid between a connected state and a blocked state, and the control unit executes a seventh process for blocking the reservoir flow path in the non-operated state, and following the seventh process, refills the first electric cylinder with the brake fluid by switching the reservoir flow path between the first electric cylinder and the reservoir tank to a connected state at the timing when the inter-cylinder flow path is switched from the connected state to the blocked state. In the present disclosure, the control unit switches the flow path between the first electric cylinder and the reservoir tank to a connected state at the timing when the flow path between the first electric cylinder and the second electric cylinder is switched from a connected state to a blocked state, thereby making it possible to complete preparations for starting the next first hold control while the second hold control is being executed.

[0045] In an electric control device according to one embodiment of the present disclosure, after switching the inter-cylinder flow path to a blocked state and before switching the second pressure accumulator flow path to an open state, the control unit drives the second electric cylinder to increase the hydraulic pressure in the wheel cylinder corresponding to the second electric cylinder to a predetermined value, and when the second pressure accumulator flow path is switched to the open state, the control unit further drives the second electric cylinder to accumulate hydraulic pressure in the accumulator. In the present disclosure, the control unit increases the hydraulic pressure in the wheel cylinder corresponding to the second electric cylinder to a predetermined value before switching the flow path between the second electric cylinder and the accumulator to a communication state. Then, the accumulator is pressurized using the remaining force of the second electric cylinder. Because brake fluid flows from the wheel cylinder corresponding to the first electric cylinder to the wheel cylinder corresponding to the second electric cylinder before switching the flow path between the first electric cylinder and the second electric cylinder to a blocked state, the amount of brake fluid flowing from the second electric cylinder to the wheel cylinder before the hydraulic pressure in the wheel cylinder corresponding to the second electric cylinder reaches a predetermined value can be reduced. This makes it possible to increase the amount of fluid in the second electric cylinder used for pressure accumulation.

[0046] [Additional Notes] The present disclosure is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present disclosure. [Explanation of symbols]

[0047] 1 Electric control device 10 Control section 12 Switching section 13 Accumulator 22 Reservoir tank A1, A2 Electric cylinder BP1, BP2 branch point C cylinder P piston Pth predetermined value VL1 Master cut valve VL2 Accumulator valve VL3, VL4 connecting valve W1, W2 wheels WC1, WC2 wheel cylinders

Claims

1. a first electric cylinder connected to a first wheel cylinder provided on a first wheel of the vehicle, and discharging brake fluid in response to driving of a first electric motor to generate a hydraulic pressure; a second electric cylinder connected to a second wheel cylinder provided on a second wheel different from the first wheel of the vehicle, and discharging brake fluid to generate a hydraulic pressure in response to driving of a second electric motor different from the first electric motor; an accumulator into which brake fluid discharged from the first electric cylinder and the second electric cylinder flows to accumulate the hydraulic pressure; a switching unit that switches between a connected state and a cut-off state, each of an inter-cylinder flow path between the first electric cylinder and the second electric cylinder, a first accumulator flow path between the first electric cylinder and the accumulator, and a second accumulator flow path between the second electric cylinder and the accumulator; a first process is executed to switch each of the inter-cylinder flow path, the first accumulator flow path, and the second accumulator flow path to a blocked state after the first electric cylinder and the second electric cylinder are deactivated; executing a second process of switching the first pressure accumulation flow path to a communication state and accumulating hydraulic pressure in the accumulator by driving the first electric cylinder, following the first process; Following the second process, a third process is executed in which the first accumulator flow path is switched to a blocked state and the inter-cylinder flow path is switched to a connected state, thereby balancing the hydraulic pressures in the inter-cylinder flow paths; and a control unit that executes, following the third process, a fourth process of switching the inter-cylinder flow path to a blocked state, switching the second accumulator flow path to a connected state, and driving the second electric cylinder to accumulate hydraulic pressure in the accumulator.

2. The control unit is a fifth process is executed in which, after the non-operated state, before the first pressure accumulation flow passage is switched to a communication state, the first electric cylinder is driven to increase a hydraulic pressure in a wheel cylinder corresponding to the first electric cylinder to a predetermined value; 2. The electric control device according to claim 1, wherein when the first accumulator flow path is switched to a connected state following the fifth process, a sixth process is executed in which the first electric cylinder is further driven to accumulate hydraulic pressure in the accumulator.

3. the switching unit further switches a reservoir flow path between each of the first electric cylinder and the second electric cylinder and a reservoir tank that stores brake fluid between a communication state and a cut-off state, The control unit executes a seventh process to block the reservoir flow path in the non-operating state, 2. The electric control device according to claim 1, wherein, following the seventh process, the reservoir flow path between the first electric cylinder and the reservoir tank is switched to a connected state at a timing when the inter-cylinder flow path is switched from a connected state to a blocked state, thereby refilling the first electric cylinder with the brake fluid.

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