JP5920022B2 - Brake device for vehicle - Google Patents

Description

  The present invention relates to a vehicle brake device provided with an electric parking brake (hereinafter referred to as EPB (Electric parking brake)).

  Conventionally, when a vehicle collides with another vehicle or the like, there is a technique in which a parking brake force is generated by automatically driving an EPB after the collision to stop the vehicle (see Patent Document 1). Thus, by automatically driving the EPB after a collision, the vehicle can be stopped without the driver performing a braking operation, and safety can be improved. However, since it is assumed that the EPB is driven with the power turned on even after the collision, there is a concern about a fire or an electric accident.

  On the other hand, there is a technique for stopping a vehicle by applying an automatic brake while shutting off a power source other than a predetermined device that should be operated after the vehicle collision after the vehicle collision (see Patent Document 2). In this way, the power supply is shut off to prevent fires and electrical accidents, while automatic braking is applied to prevent secondary collisions.

JP 2003-276583 A JP-A-6-234342

  However, with the technique described in Patent Document 2, the power source for automatic braking and the like is not shut off, so the possibility of a fire or an electrical accident remains. For this reason, it is conceivable to turn off the power supply for automatic braking after applying the automatic brake, but it is not known whether it has the self-holding ability of the braking force. It is unknown whether it can be blocked.

  In view of the above points, the present invention can quickly shut off the electric system of the vehicle, and can automatically generate the braking force after the vehicle collision while allowing the braking force to be self-held. An object of the present invention is to provide a vehicle brake device.

  In order to achieve the above object, according to the invention described in claim 1, in addition to the power source (5), a battery that can store power for generating parking brake force by operating the EPB (2) at least once. 9), and when the collision detection means (10) detects that the vehicle has collided, the power switch (7) is turned off to cut off the power supply from the power source (5), and the battery (9 The parking brake force is generated by operating the EPB (2) on the basis of the power supply from the above.

  As described above, the battery (9) is provided that can store the power for generating the parking brake force by operating the EPB (2) at least once. Thus, even if the power source (5) is shut off immediately in the event of a vehicle collision, the EPB (2) can be operated by the battery (9), so that the electric system of the vehicle can be shut off quickly and the battery (9 It is possible to automatically generate a braking force based on the power supply from) and to be able to hold the braking force by itself.

  For example, as described in claim 2, the power source may include a vehicle-mounted battery (5), and the capacitor may include a capacitor (9) connected to the vehicle-mounted battery (5).

  According to a third aspect of the present invention, it is provided with a storage state detection means for detecting a storage state of the battery (9), and the storage state detection means detects that the storage state is sufficient to operate the EPB (2). When this happens, the power switch (7) is turned off to cut off the power supply from the power supply (5), and the EPB (2) is activated based on the power supply from the battery (9) to generate the parking brake force. It is characterized by letting.

  Thus, only when the storage state is sufficient to operate the EPB (2), the power switch (7) is turned off to cut off the power supply from the power source (5) and The parking brake force may be generated by operating the EPB (2) based on the power supply.

  In this case, as described in claim 4, when the storage state detection means detects that the storage state is insufficient to operate the EPB (2), the power switch (7) remains on. After operating the EPB (2) based on the power supply from the power source (5) to generate the parking brake force, the power switch (7) is turned off to cut off the power supply from the power source (5) You should do it.

  In invention of Claim 5, it has a service brake (1) which has an automatic pressurization function which generates service brake force by automatically pressurizing brake fluid pressure in a wheel cylinder provided for every wheel, When it is detected by the collision detection means (10) that the vehicle has collided, in addition to operating the EPB (2) to generate a parking brake force, an automatic pressurizing function by the service brake (1) It is characterized by generating service brake force.

  As described above, when it is determined that the vehicle has collided, the service brake force is generated simultaneously with the parking brake force by using the automatic pressurizing function of the service brake (1), so that the braking force can be secured earlier. You may do it. In this way, it becomes possible to generate a larger braking force at the time of a collision, and it is possible to stop more quickly if the vehicle is in a state before stopping.

  In the invention according to claim 6, the capacitor (9) is connected to the power line (6) to store electricity based on the power supply from the power source (5), and the power line (6) An auxiliary power switch (8) is provided in addition to the switch (7), and the power supply from the capacitor (9) to the EPB (2) is turned on and off by the auxiliary power switch (8). Based on the power supply, the EPB (2) is activated to generate the parking brake force, and then the auxiliary power switch (8) is turned off to cut off the power supply from the battery (9) to the EPB (2). It is characterized by doing.

  In this way, after the EPB (2) is operated based on the power supply from the battery (9) to generate the parking brake force and the wheels are locked, the auxiliary power switch (8) is also switched from on to off. The power supply from the battery (9) is also stopped to bring the EPB (2) down. As a result, the electric system of the vehicle can be promptly shut off.

  In addition, the code | symbol in the bracket | parenthesis of each said means shows the correspondence with the specific means as described in embodiment mentioned later.

It is the figure which showed the circuit structure of the brake device for vehicles concerning 1st Embodiment of this invention. It is the flowchart which showed the detail of the power supply control process at the time of the collision which EPB-ECU4 performs. It is the figure which showed the timing chart at the time of the collision when the electrical storage state of the capacitor 9 is sufficient.

(First embodiment)
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram illustrating a circuit configuration of a vehicle brake device according to the present embodiment. With reference to this figure, the structure of the brake device for vehicles concerning this embodiment is demonstrated.

  As shown in FIG. 1, the vehicle brake device includes a service brake 1 that generates a service brake force based on a driver's stepping force and an EPB 2 that regulates the movement of the vehicle during parking.

  The service brake 1 is a hydraulic brake mechanism that generates a brake fluid pressure based on depression of a brake pedal by a driver and generates a service brake force based on the brake fluid pressure. Specifically, the service brake 1 boosts the pedaling force according to the depression of the brake pedal by the driver with a booster, and then applies the brake hydraulic pressure corresponding to the boosted pedaling force to the master cylinder (hereinafter referred to as M). / C)). The brake fluid pressure is transmitted to a wheel cylinder (hereinafter referred to as W / C) provided in the brake mechanism of each wheel, thereby generating a service brake force. Further, an actuator for controlling the brake fluid pressure is provided between the M / C and the W / C, and various controls for adjusting the service brake force generated by the service brake 1 and improving the safety of the vehicle. (For example, anti-skid control).

  Various controls using the actuator are executed by an ESC (Electronic Stability Control) -ECU 3. For example, by outputting a control current for controlling various control valves (not shown) provided in the actuator and a motor for driving the pump from the ESC-ECU 3, the hydraulic circuit provided in the actuator is controlled and transmitted to the W / C. W / C pressure is controlled. Thereby, avoidance of wheel slip is performed, and the safety of the vehicle is improved. For example, the actuator is a pressure-increasing control valve that controls whether the brake fluid pressure generated in the M / C or the brake fluid pressure generated by driving the pump is applied to the W / C for each wheel. In addition, it is equipped with a pressure-reducing control valve that reduces the W / C pressure by supplying brake fluid in each W / C to the reservoir, and is configured to increase / hold / depressurize the W / C pressure. Yes. In addition, the actuator can realize the automatic pressurization function of the service brake 1, and automatically pressurizes W / C even when there is no brake operation based on pump drive and control of various control valves. I can do it. Since the configuration of this actuator has been conventionally known, the details are omitted here.

  On the other hand, the EPB 2 generates a parking brake force by controlling a brake mechanism with an electric motor, and is controlled by an EPB control device (hereinafter referred to as EPB-ECU) 4.

  EPB2 has, for example, a reduction gear having a gear mechanism that decelerates and amplifies the rotational force of the electric motor, and a linear motion conversion device that converts the rotational force of the electric motor decelerated and amplified by the reduction device into a linear motion. The brake pad is moved based on the linear motion converted by the linear motion converter. Specifically, the brake pad is brought into contact with the brake disk and pressed by driving the electric motor in the forward direction to generate a parking brake force, and the brake pad is moved in the reverse direction by driving the electric motor in the reverse direction. The parking brake force is configured to be released from the parking space.

  The EPB 2 configured as described above can hold the brake pad in the same position even after the electric motor is stopped by the frictional force generated by the engagement between the male screw groove and the female screw groove in the screw mechanism constituting the linear motion conversion device. . Therefore, the EPB 2 has a self-holding function capable of holding the parking brake force when the electric motor is stopped in a state where the parking brake force is generated.

  A vehicle-mounted battery 5 is used as a power source for the ESC-ECU 3 that controls the service brake 1 and the EPB-ECU 4 that controls the EPB 2. The ESC-ECU 3 and the EPB-ECU 4 are connected to the in-vehicle battery 5, and based on the power supply from the in-vehicle battery 5, the ESC-ECU 3 drives various control valves and motors provided in the actuator, and EPB- ECU4 drives the electric motor of EPB2.

  The power supply line 6 that supplies power to the EPB-ECU 4 from the in-vehicle battery 5 is provided with a power switch 7 and an auxiliary power switch 8. The power line 6 is turned on and off by turning on and off the switches 7 and 8. Can be controlled. The power switch 7 and the auxiliary power switch 8 are connected in series. The power switch 7 is disposed on the in-vehicle battery 5 side, and the auxiliary power switch 8 is disposed on the EPB-ECU 4 side. The power switch 7 and the auxiliary power switch 8 can be turned on / off based on a control signal from the EPB-ECU 4.

  In addition, a capacitor 9 serving as a capacitor constituting an auxiliary power source is connected in parallel to the in-vehicle battery 5, and the capacitor 9 is charged based on power supply from the in-vehicle battery 5. Capacitor 9 is configured with a capacity that can store power for generating parking brake force by operating EPB 2 at least once even when power supply from in-vehicle battery 5 to EPB-ECU 4 is interrupted.

  Specifically, the capacitor 9 is connected to the power supply line 6 between the power supply switch 7 and the auxiliary power supply switch 8, and is charged when the power supply switch 7 is turned on to store electricity. . When the power switch 7 is turned off and the auxiliary power switch 8 is turned on, the EPB-ECU 4 controls the electric motor of the EPB 2 by supplying electric power based on the electric charge stored in the capacitor 9 to increase the parking brake force. Can be generated.

  The EPB-ECU 4 detects the voltage of the in-vehicle battery 5 serving as a power supply source (hereinafter referred to as battery voltage). Then, by determining whether or not the battery voltage is higher than a predetermined threshold, it is possible to detect that the battery voltage is low and insufficient to operate the EPB 2.

  Furthermore, the vehicle brake device according to the present embodiment includes an acceleration sensor 10. A detection signal of the acceleration sensor 10 is input to the EPB-ECU 4 so that the vehicle acceleration can be detected by the EPB-ECU 4. When the vehicle collides, the acceleration of the vehicle changes abruptly. Therefore, the EPB-ECU 4 can determine that the vehicle has collided when the vehicle acceleration changes, for example, when the vehicle acceleration change speed exceeds a predetermined threshold. The vehicle acceleration is assumed to be a vehicle longitudinal acceleration and a vehicle lateral acceleration, which can be detected by a longitudinal acceleration sensor and a lateral acceleration sensor, respectively, and the acceleration sensor 10 here includes any acceleration. .

  Next, the operation of the vehicle brake device configured as described above will be described. FIG. 2 is a flowchart showing details of a power supply control process at the time of a collision executed by the EPB-ECU 4 provided in the vehicle brake device according to the present embodiment. With reference to this figure, operation | movement of the brake device for vehicles is demonstrated.

  First, during a non-collision when the vehicle is not colliding, a normal braking operation is performed. That is, the service brake 1 generates a brake fluid pressure based on the driver's depression of the brake pedal, and generates a service brake force based on the brake fluid pressure. Further, when wheel slip can occur during braking, the anti-skid control is executed by controlling various control valves and motors in the ESC-ECU 3, and the wheel slip is suppressed to avoid the wheel from being locked.

  When the vehicle collides, the change rate of the vehicle acceleration detected based on the detection signal of the acceleration sensor 10 exceeds a predetermined threshold value, so that the EPB-ECU 4 determines that the vehicle has collided. Based on this determination, the EPB-ECU 4 executes the process shown in the flowchart of FIG.

  First, in step 100, it is determined whether or not the battery voltage is higher than a predetermined threshold value. When the battery voltage is higher than a predetermined threshold, it is assumed that the capacitor 9 is also charged enough to operate the EPB 2. For this reason, when an affirmative determination is made here, the EPB 2 can be operated based on the power supply from the capacitor 9 even if the power supply is shut off and the power supply from the in-vehicle battery 5 is stopped. Yes. Conversely, when a negative determination is made here, it may be difficult to operate the EPB 2 based on the power supply from the capacitor 9 when the power supply is shut off and the power supply from the in-vehicle battery 5 is stopped. There is sex. Therefore, if an affirmative determination is made in step 100, the processes of steps 110 to 130 are executed, and if a negative determination is made, the processes of steps 140 to 150 are executed.

  Specifically, when an affirmative determination is made in step 100, the system is shut down in each part including the engine system by shutting off the power in step 110. At this time, the power supply from the in-vehicle battery 5 to the EPB-ECU 5 is also stopped by switching the power switch 7 from on to off. Subsequently, in step 120, the EPB 2 is operated based on the power supply from the capacitor 9 to generate a parking brake force, and the wheels are locked. Thereafter, in step 130, the auxiliary power switch 8 is also switched from on to off, the power supply from the capacitor 9 to the EPB-ECU 4 is also stopped, and the system of the EPB 2 is brought down.

  On the other hand, when a negative determination is made in step 100, the parking brake force is generated by operating the EPB 2 based on the power supply from the in-vehicle battery 5 and the wheels are locked before the power is turned off in step 140. Thereafter, in step 150, the power supply is shut off to shut down the various parts including the engine system, and the power switch 7 and the auxiliary power switch 8 are switched from on to off, and the EPB-ECU 4 is switched from the vehicle battery 5 or the capacitor 9 to the EPB-ECU 4. The power supply to the system is stopped and EPB2 is also brought down.

  In this manner, the storage state of the capacitor 9 is detected based on the battery voltage, and it can be determined whether or not the storage state is sufficient to operate the EPB 2. If the power storage state is sufficient at the time of a vehicle collision, the power supply from the in-vehicle battery 5 to each part including the engine system is immediately stopped so that the electric system of the vehicle can be shut off quickly, and the capacitor 9 The EPB 2 is reliably operated based on the power supply from the vehicle, and the parking brake force is automatically generated. Further, the parking brake force generated at this time is braked by the frictional force generated by the engagement between the male screw groove and the female screw groove in the screw mechanism constituting the linear motion conversion device even after the power supply from the capacitor 9 is stopped. Since the pad can be held in the same position, it is self-held. Further, after the parking brake force is generated, the auxiliary power switch 8 is turned off and the EPB 2 is also brought down, so that the electric system of the vehicle can be shut off quickly.

  Further, if the state of charge is not sufficient at the time of a vehicle collision, the power supply from the in-vehicle battery 5 is not immediately stopped, but the EPB 2 is reliably operated based on the power supply from the in-vehicle battery 5, and the parking brake force is automatically set. Is generated so that the parking brake force can be self-maintained, and thereafter the power supply from the in-vehicle battery 5 is stopped so that the electric system of the vehicle can be shut off quickly.

  As described above, the EPB 2 is operated by the capacitor 9 when the storage state of the capacitor 9 is sufficient, and the EPB 2 is operated by the in-vehicle battery 5 when the storage state of the capacitor 9 is insufficient. Accordingly, the electric system of the vehicle can be quickly shut down by shutting off the power source at the earliest possible stage while ensuring that the EPB 2 can be operated and maintained without fail regardless of the storage state of the capacitor 9.

  FIG. 3 is a diagram showing a timing chart at the time of collision when the storage state of the capacitor 9 is sufficient. As shown in this figure, when a large acceleration that exceeds a predetermined threshold is detected, the power switch 7 is switched from on to off at the same time, and the power supply from the in-vehicle battery 5 to the ESC-ECU 3 is stopped. Is done. Thereby, since the service brake force by the service brake 1 decreases, the braking force generated in the vehicle decreases.

  However, since the auxiliary power switch 8 remains on at this time, the EPB 2 is operated based on the power supply from the capacitor 9. As a result, a parking brake force is generated and the braking force is increased again. When the motor current flowing through the electric motor of EPB2 reaches a predetermined value, the electric motor is stopped and the auxiliary power switch 8 is switched from on to off, assuming that a desired parking brake force is generated. In this way, it is possible to operate the EPB 2 based on the power supply from the capacitor 9 to generate the parking brake force and to self-hold the parking brake force while shutting off the power supply at an earlier stage.

  As described above, according to the vehicle brake device of the present embodiment, the electric system of the vehicle can be quickly shut down by immediately shutting off the power supply in the event of a vehicle collision, and power supply from the capacitor 9 can be performed. It is possible to automatically generate a braking force based on the above and to be able to self-hold the braking force. When the storage state of the capacitor 9 is insufficient, the EPB 2 is reliably operated based on the power supply from the in-vehicle battery 5 so that the brake force can be self-maintained, and thereafter the power source is shut off to It is possible to quickly shut off the electrical system.

(Other embodiments)
In the above embodiment, the parking brake force is generated by operating the EPB 2 based on the power supply from the capacitor 9. However, since the service brake force is not always generated at the time of the collision, when it is determined that the vehicle has collided, the service brake force is parked by using the automatic pressurizing function of the service brake 1. It may be generated at the same time as the force so that the braking force can be secured earlier. In this way, it becomes possible to generate a larger braking force at the time of a collision, and it is possible to stop more quickly if the vehicle is in a state before stopping. Moreover, since the operation | movement based on the electric power supply from the vehicle-mounted battery 5 can be performed when the electrical storage state of the capacitor 9 is insufficient, the automatic pressurization function of the service brake 1 can also be used only in that case. .

  In the above-described embodiment, the storage state detection unit has been described by taking as an example the case where the storage state of the capacitor 9 as a storage device is detected based on the battery voltage, but other methods, for example, the voltage across the capacitor 9 The storage state may be detected.

  Moreover, although the said embodiment demonstrated the case where the acceleration sensor 10 was used as a collision detection means, you may detect a vehicle based on the image of a vehicle-mounted camera, for example. When the acceleration sensor 10 is used, when the acceleration sensor 10 of the airbag device is used, or when a collision of the vehicle is detected by the airbag device, a detection signal indicating that is sent through the in-vehicle LAN or the like. Collision detection may be performed.

  Furthermore, although the case where the ESC-ECU 3 that controls the service brake 1 and the EPB-ECU 4 that controls the EPB 2 are configured by separate ECUs has been described in the above embodiment, they may be integrated.

  DESCRIPTION OF SYMBOLS 1 ... Service brake, 2 ... EPB, 3 ... ESC-ECU, 4 ... EPB-ECU, 5 ... In-vehicle battery, 6 ... Power supply line, 7 ... Power switch, 8 ... Auxiliary power switch, 9 ... Capacitor, 10 ... Acceleration sensor

Claims (6)

A parking brake force is generated by being connected to a power supply line (6) connected to a power supply (5) provided in the vehicle and operated based on power supply from the power supply (5) through the power supply line (6). And an electric parking brake (2) having a self-holding ability to hold the parking brake force generated even after the power supply from the power source (5) is cut off,
An electric parking brake control device (4) for controlling the operation of the electric parking brake (2);
A power switch (7) provided on the power line (6) for controlling on / off of power supply from the power source (5) to the electric parking brake control device (4);
A battery (9) for storing electricity for generating the parking brake force by operating the electric parking brake (2) at least once;
Collision detection means (10) for detecting that the vehicle has collided,
When the collision detection means (10) detects that the vehicle has collided, the power switch (7) is turned off to cut off the power supply from the power source (5), and the battery (9 ) To actuate the electric parking brake (2) to generate the parking brake force based on power supply from the vehicle brake device.   The vehicle brake device according to claim 1, wherein the power source is an in-vehicle battery (5), and the capacitor is a capacitor (9) connected to the in-vehicle battery (5). A storage state detection means for detecting a storage state of the battery (9);
When the storage state detection means detects that the storage state is sufficient to operate the electric parking brake (2), the power switch (7) is turned off and the power source (5) is turned off. 3. The parking brake force is generated by operating the electric parking brake (2) based on the power supply from the battery (9) to cut off the electric power supply of the vehicle. Brake device for vehicles.   When the storage state detection means detects that the storage state is insufficient to operate the electric parking brake (2), the power switch (7) remains on and the power source (5) After operating the electric parking brake (2) based on the power supply from the vehicle to generate the parking brake force, the power switch (7) is turned off to cut off the power supply from the power source (5) The vehicle brake device according to claim 3, wherein the vehicle brake device is a vehicle brake device. A service brake (1) having an automatic pressurizing function for generating a service brake force by automatically pressurizing a brake fluid pressure in a wheel cylinder provided for each wheel;
When the collision detection means (10) detects that the vehicle has collided, in addition to operating the electric parking brake (2) to generate the parking brake force, the service brake (1) The vehicle brake device according to any one of claims 1 to 4, wherein the service brake force is generated by the automatic pressurizing function. The battery (9) is connected to the power supply line (6) to store electricity based on power supply from the power supply (5),
The power line (6) is provided with an auxiliary power switch (8) in addition to the power switch (7). The auxiliary power switch (8) is connected to the electric parking brake (9) from the battery (9). The power supply to 2) is turned on and off,
After the electric parking brake (2) is operated based on the power supply from the battery (9) to generate the parking brake force, the auxiliary power switch (8) is turned off to turn off the battery (9 The vehicle brake device according to any one of claims 1 to 5, wherein the electric power supply to the electric parking brake (2) is also cut off.

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