JP4876834B2 - Brake control device for vehicle - Google Patents

Description

  The present invention relates to a vehicle brake control device that prevents rust from occurring in a brake rotor.

  A vehicle brake device generally includes a disc-shaped brake rotor that rotates integrally with a wheel, a brake pad that is opposed to the brake rotor, and a wheel cylinder that presses the brake pad against the brake rotor. Braking is performed by frictional force generated between the contact surfaces of the brake pad and the brake rotor.

  In this vehicular brake device, moisture may adhere to the brake rotor due to rain or fog, and rust is generated on the brake rotor when a long time elapses while moisture remains attached. If rust is generated on the brake rotor, the thickness of the brake rotor will become uneven, causing the brake rotor to vibrate abnormally (brake judder) when the brake pad is pressed against the brake rotor, or causing abnormal noise to the brake rotor. To do.

Then, what is described in the following patent document is known as a vehicle brake control apparatus that can remove rust when the brake rotor is rusted. This vehicle brake control device performs braking using both regenerative braking force and friction braking force during normal braking, and does not generate regenerative braking force when it is determined that the brake rotor is rusted. In addition, the friction braking force is preferentially generated, and the rust of the brake rotor is removed by the friction braking force (Patent Document 1).
JP 2006-103630 A

  However, even if the control that preferentially generates the frictional braking force is performed in this way, the abnormal vibration or squeal of the brake rotor described above is generated after the rust is generated on the brake rotor until the rust is removed. It cannot be avoided.

  In addition, in order to remove the rust generated in the brake rotor, a technology to improve the material of the brake pad and a technology to change the structure of the brake pad have been proposed, but rust is generated even if these technologies are adopted. After that, until the rust is removed, abnormal vibration and squeal of the brake rotor occur.

  The problem to be solved by the present invention is to provide a vehicle brake control device capable of preventing the brake rotor from being rusted.

In order to solve the above-mentioned problem, a moisture adhesion determining means for determining whether or not moisture is attached to a brake rotor that generates a friction braking force, and a long time that rust is generated on the brake rotor to which moisture has adhered Long-time parking determination means for determining whether or not parking is performed, and it is determined by the moisture adhesion determination means that moisture has adhered to the brake rotor, and the long-time parking determination means determines the long-time parking. The vehicle brake control device employs a configuration having braking force increase control means for performing control for increasing the friction braking force during traveling when it is determined that the friction braking force is increased.

  The vehicle brake control device further includes target temperature setting means for setting a target temperature of the brake rotor, and brake rotor temperature acquisition means for acquiring a current temperature of the brake rotor, wherein the braking force increase control means Preferably, the larger the temperature difference between the target temperature set by the target temperature setting means and the temperature acquired by the brake rotor temperature acquisition means, the larger the amount of increase in the friction braking force is. It is more preferable that an outside air temperature acquisition unit that acquires the air temperature is provided, and that the target temperature setting unit sets the target temperature higher as the outside air temperature acquired by the outside air temperature acquisition unit is lower.

  Further, the vehicle brake control device according to the driving force generating means for generating the driving force of the vehicle and the driving force generated by the driving force generating means according to the increase amount of the friction braking force by the braking force increasing means. Driving force addition control means for performing control for adding a driving force having a magnitude can be further provided.

  In the vehicle brake control device according to the present invention, when it is determined that moisture is attached to the brake rotor, and it is determined that parking is performed for a long time such that rust is generated on the brake rotor in which moisture is attached. In addition, the friction braking force generated in the brake rotor is increased more than in normal braking, and the temperature of the brake rotor is increased more than in normal braking, so that the water adhering to the brake rotor evaporates before parking for a long time. Further, it is possible to prevent rust from being generated in the brake rotor.

  Further, as the temperature difference between the target temperature set by the target temperature setting means and the temperature acquired by the brake rotor temperature acquisition means is larger, the braking force increase control means increases the increase amount of the friction braking force. As the brake rotor temperature decreases, the amount of increase of the friction braking force by the braking force increase control means increases. Therefore, even when the temperature of the brake rotor before parking for a long time is low, the brake rotor is more reliably The water can be evaporated.

  Further, the lower the outside air temperature acquired by the outside air temperature acquisition means, the higher the target temperature is set by the target temperature setting means, the lower the outside air temperature is, and the faster the cooling speed of the brake rotor is, Since the amount of increase in the friction braking force by the braking force increase control means increases and the temperature of the brake rotor rises greatly, the water in the brake rotor can be reliably evaporated even when the outside air temperature is low.

  Further, the apparatus further includes a driving force addition control means for performing control for adding a driving force having a magnitude corresponding to the amount of increase of the friction braking force by the braking force increasing means to the driving force generated by the driving force generating means. In addition, since the driving force addition control means absorbs the influence of the braking force increasing means that increases the friction braking force on the movement of the vehicle by adding the driving force, it is difficult for the driver to feel uncomfortable.

  FIG. 1 shows a piping system diagram of a brake system that employs a vehicle brake control device according to an embodiment of the present invention. This brake system has a master cylinder 2 that converts the depression force of the brake pedal 1 into a hydraulic pressure, and a reservoir 4 that stores brake fluid is attached to the master cylinder 2.

  The master cylinder 2 is connected to the wheel cylinder 9RL through a master cylinder side pipe line 3A, a proportional control valve 5A, a pressure increase pipe line 6A, a pressure increase control valve 7RL, and a wheel cylinder side pipe line 8RL in this order. The wheel cylinder 9RL presses a brake pad (not shown) against the disc-like brake rotor 10RL that rotates integrally with the left rear wheel RL. At this time, the brake rotor 10RL is supplied with liquid supplied to the wheel cylinder 9RL. A friction braking force having a magnitude corresponding to the pressure is generated.

  The wheel cylinder side conduit 8RL is connected to the decompression conduit 12A via the decompression control valve 11RL. The pressure increasing line 6A and the pressure reducing line 12A are connected via a pump 14A driven by a pump drive motor 13. The proportional control valve 5A changes the differential pressure between the pressure increasing pipeline 6A and the master cylinder side pipeline 3A in accordance with a control signal from a brake electronic control unit (hereinafter referred to as “brake ECU”) 15 shown in FIG.

  The decompression pipeline 12A and the master cylinder side pipeline 3A are connected via an auxiliary reservoir 16A. When the brake pedal 1 is operated, the auxiliary reservoir 16A contracts the spring 17A due to the hydraulic pressure generated in the master cylinder side conduit 3A, and the valve body 18A is seated on the valve seat 19A, so that the brake fluid flows into the auxiliary reservoir 16A. However, when the pump 14A is driven, the hydraulic pressure in the auxiliary reservoir 16A decreases, the spring 17A extends, the valve body 18A moves away from the valve seat 19A, and in this state, the master cylinder side pipe passes through the auxiliary reservoir 16A. Brake fluid flows from the path 3A to the pressure reducing line 12A.

  The piping system configured as described above supplies the hydraulic pressure of the master cylinder 2 to the wheel cylinder 9RL as it is by opening the pressure increase control valve 7RL and closing the pressure reduction control valve 11RL during normal braking. Further, when supplying a hydraulic pressure larger than that during normal braking to the wheel cylinder 9RL, by driving the pump 14A, the hydraulic pressure in the master cylinder side pipe line 3A is increased and supplied to the wheel cylinder 9RL. At this time, the increase amount of the hydraulic pressure can be changed by controlling the differential pressure before and after the proportional control valve 5A.

  In this brake system, a piping system similar to that of the left rear wheel RL is also connected to the right front wheel FR, the left front wheel FL, and the right rear wheel RR.

  In addition, as shown in FIG. 2, this brake system includes a brake ECU 15, an engine ECU 20, a transmission ECU 21, a meter ECU 22, a navigation ECU 23, and an automatic parking assistance control ECU 24 connected to a bus 25 of the in-vehicle LAN. Information can be exchanged between the ECUs.

  As shown in FIG. 3, the brake ECU 15 includes a master cylinder hydraulic pressure sensor 26 that detects the hydraulic pressure of the master cylinder 2, wheel cylinder hydraulic pressure sensors 27RL to 27RR that detect hydraulic pressures of the wheel cylinders 9RL to 9RR, Signals are input from wheel speed sensors 28RL to 28RR that detect the rotational speeds of the wheels RL to RR. In addition, control signals are output from the brake ECU 15 to the proportional control valves 5A and 5B, the pressure increase control valves 7RL to 7RR, the pressure reduction control valves 11RL to 11RR, and the pump drive motor 13. The meter ECU 22 includes a rain sensor 29 for detecting the attachment of water droplets on the windshield, a wiper switch 30 for operating the wiper, a hazard switch 31 for operating a hazard lamp, and an outside temperature sensor 32 for detecting the temperature outside the vehicle. A signal is input from.

  Control of the brake system configured as described above will be described with reference to FIGS.

FIG. 4 shows the main routine of this control. First, the brake ECU15 performs a determination of whether the water is attached to a brake rotor 10RL～10RR (Step _S 1). This determination is made, for example, when a detection signal of the rain sensor 29 or an operation signal of the wiper switch 30 is acquired from the meter ECU 22 and when water droplets adhere to the windshield or an operation for operating the wiper is performed. It is determined that moisture is attached to the rotors 10RL to 10RR.

The brake ECU15 performs a determination of whether carried out immediately after prolonged parking extent that rust occurs in a state where water is attached brake rotor 10RL~10RR (step _S 1). In this determination, for example, information about whether or not it is just before arrival at the destination is acquired from the navigation ECU 23, and further, an operation signal for the hazard switch 31 is acquired from the meter ECU 22, and the hazard lamp is turned on immediately before arrival at the destination. When the operation is performed, it is determined that the long-time parking is performed immediately after.

Then, moisture adhering to the brake rotor 10RL～10RR, and when the long parking is determined to be performed immediately calculates the (Step _S 2), the target temperature of the brake rotor 10RL～10RR (step S ₃₎ Subsequently, by calculating the temperature rise of the brake rotor 10RL~10RR required to the target temperature (step S _4), calculates the braking force increase amount corresponding to the computed temperature rise (Step S ₅ ) Further, a driving force addition amount corresponding to the braking force increase amount is calculated (Step S ₆ ).

On the other hand, no moisture adheres to the brake rotor 10RL～10RR, or, when the long-time parking is determined not performed immediately (step S _2), both the driving force additional amount of braking force increase amount Set to zero (step S ₇ ).

Thereafter, a process of generating a braking force obtained by adding the braking force increase amount to the braking force during normal braking and a driving force corresponding to the additional driving force amount is performed (step S ₈ ).

Figure 5 shows a subroutine corresponding to the step S ₃ of the main routine. First, the detection signal of the outside air temperature sensor 32 is acquired from the meter ECU 22 (step S ₁₁ ), and the target temperature is set to a default value (for example, 120 degrees) (step S ₁₂ ). When the outside air temperature is high (for example, when 20 degrees <outside temperature), the target temperature is left at the default value (step S ₁₃ ), and when the outside temperature is room temperature (for example, when 10 degrees <outside temperature ≦ 20 degrees) ), because speed is high to cool the brake rotor 10RL~10RR than at a high temperature, sets the target temperature to 20 degrees larger than the default value (step _{S 14, S} 15). When the outside air temperature is low (for example, when 0 degree <outside temperature ≦ 10 degrees), the target temperature is set to a value that is 50 degrees larger than the default value (steps S ₁₆ and S ₁₇ ). Outside temperature when the sub-zero, the speed of chilling brake rotor 10RL~10RR is particularly fast, set the target temperature to 80 ° greater than the default value (Step _{S 18, S} 19).

6 shows a subroutine corresponding to the step S ₄ of the main routine. First, to get the current temperature of the brake rotor 10RL～10RR (step _S 21). The temperature of the brake rotors 10RL to 10RR is acquired by, for example, calculating the temperature increase amount of the brake rotors 10RL to 10RR based on the detection signals of the wheel cylinder hydraulic pressure sensors 27RL to 27RR and the detection signals of the wheel speed sensors 28RL to 28RR. The amount of temperature increase is integrated with the initial temperature of the brake rotors 10RL to 10RR. Thus when the temperature of the computed current brake rotor 10RL～10RR is lower than the target temperature (step _{S 22),} calculates the difference between the target temperature and the current temperature of the brake rotor 10RL～10RR, the calculated value, is set as a temperature increase amount required for the brake rotor 10RL~10RR the target temperature (step _S 23). On the other hand, when the temperature of the brake rotor 10RL~10RR is less than the target temperature (step _{S 22),} set to zero as the temperature increase required for the brake rotor 10RL~10RR the target temperature (step _S 24).

7 shows a subroutine corresponding to step S ₅ of the main routine. First, it calculates the target braking force corresponding to the temperature increasing amount required for a brake rotor 10RL~10RR the target temperature (step _S 31). This calculation is performed, for example, based on a correspondence relationship between a preset amount of temperature increase of the brake rotors 10RL to 10RR and the target braking force as shown in FIG. In FIG. 8, when the amount of temperature rise exceeds a certain amount, the target braking force is set to a certain value to prevent overloading of the brake device.

Next, it is determined based on the detection signal of the master cylinder hydraulic pressure sensor 26 whether or not the driver is performing a braking operation (step S ₃₂ ). The braking force required by operating the brake pedal 1 is calculated based on the hydraulic pressure of the master cylinder 2, and the calculated value is set as the required braking force (step _S33 ). On the other hand, when the driver is not performing a braking operation (step S ₃₂ ), the automatic parking assist control ECU 24 maintains the vehicle speed at a constant low speed when the vehicle is in a state immediately before parking (for example, when the vehicle is in a state immediately before parking). The braking force required for performing control or control for automatically decelerating the vehicle and stopping the vehicle at the parking target position is set as the required braking force (step S ₃₄ ). Thereafter, when the target braking force is larger than the required braking force (step S ₃₅ ), the difference between the target braking force and the required braking force is set as the braking force increase amount (step S ₃₆ ). When the target braking force is less than or equal to the required braking force (step S ₃₅ ), zero is set as the braking force increase amount (step S ₃₇ ).

9 shows a subroutine corresponding to the step S ₆ of the main routine. When the braking force increase amount is larger than zero (step S ₄₁ ), the driving force addition amount corresponding to the braking force increase amount is calculated based on the correspondence relationship between the braking force increase amount and the driving force addition amount shown in FIG. (Step _S42 ). On the other hand, when the braking force increase amount is zero (step S ₄₁ ), zero is set as the additional driving force amount (step S ₄₃ ).

The brake ECU 15 calculates the braking force increase amount as described above, and the proportional control valve 5A so that a braking force obtained by adding the braking force increase amount to the braking force during normal braking is generated in each wheel RL to RR. , 5B, pressure increase control valves 7RL～7RR, outputs a control signal to the pressure reduction control valve 11RL～11RR (step _S 8). Further, a control signal is output to the engine ECU 20 so as to generate a driving force with the additional driving force amount calculated as described above (step S ₈ ).

  When this vehicle brake control device is used, the friction braking force applied to the brake rotors 10RL to 10RR is normally braked when it is determined that parking is performed immediately after a long period of time with moisture adhering to the brake rotors 10RL to 10RR. The temperature of the brake rotors 10RL to 10RR increases more than during normal braking. Therefore, it is possible to prevent moisture adhering to the brake rotors 10RL to 10RR from evaporating before parking for a long period of time and causing rust on the brake rotors 10RL to 10RR. Further, at this time, since a driving force corresponding to the increase amount of the friction braking force is generated, the influence on the movement of the vehicle due to the increase of the friction braking force is absorbed, and the driver does not feel uncomfortable.

  Further, when this vehicle brake control device is used, the lower the temperature of the brake rotors 10RL to 10RR, the greater the amount of temperature increase of the brake rotors 10RL to 10RR necessary for setting the brake rotors 10RL to 10RR to the target temperature. The amount of increase in braking force also increases. Therefore, even when the temperature of the brake rotor before parking for a long time is low, the water in the brake rotor can be reliably evaporated. Further, the amount of increase in braking force increases as the outside air temperature decreases, and the temperature of the brake rotor increases greatly. Therefore, even when the outside air temperature is low, the water in the brake rotor can be reliably evaporated.

Piping system diagram of brake system adopting vehicle brake control device of embodiment of this invention Brake system block diagram Block diagram of brake ECU and meter ECU shown in FIG. The flowchart which shows the main routine of control of brake ECU shown in FIG. Flow diagram showing the process of step S ₃ in Fig. 4 Flow diagram showing the process of step S ₄ in FIG. 4 Flow diagram showing the process of step S ₅ in FIG. 4 The figure which shows an example of the correspondence of the temperature rise amount of a brake rotor, and target braking force Flow diagram showing the process of step S ₆ in FIG. 4 The figure which shows an example of the correspondence of braking force increase amount and driving force addition amount

Explanation of symbols

10RL, 10FR, 10FL, 10RR Brake rotor 20 Engine ECU

Claims (4)

Moisture adhesion determining means (S ₁ ) for determining whether moisture is adhered to the brake rotor (10RL to 10RR) that generates the friction braking force;
Long-time parking determination means (S ₁ ) for determining whether or not long-time parking is performed to such an extent that rust is generated on the brake rotor (10RL to 10RR) to which moisture has adhered;
When the moisture adhesion determining means determines that moisture is attached to the brake rotor, and the long-time parking determining means determines that the long-time parking is performed, the friction braking force is normally braked. Braking force increase control means (S ₅ ) for performing control to increase more than during driving ,
A brake control device for a vehicle. Target temperature setting means (S ₃ ) for setting a target temperature of the brake rotor (10RL to 10RR);
Brake rotor temperature acquisition means (S ₂₁ ) for acquiring the current temperature of the brake rotor (10RL to 10RR);
The braking force increase control means (S ₅ ) increases the temperature difference between the target temperature set by the target temperature setting means (S ₃ ) and the temperature acquired by the brake rotor temperature acquisition means (S ₂₁ ). The vehicle brake control device according to claim 1, wherein an increase amount of the friction braking force is increased. An outside temperature acquisition means (S ₁₁ ) for acquiring the outside temperature of the vehicle;
The target temperature setting means (S ₃₎ for a vehicle brake control device according to claim 2, the outside air temperature acquired by the outdoor temperature acquisition means (S ₁₁₎ is set higher the lower the said target temperature. Driving force generating means (20) for generating a driving force of the vehicle;
Driving force addition control means for controlling the driving force generated by the driving force generating means (20) to add a driving force having a magnitude corresponding to the amount of increase of the friction braking force by the braking force increasing means (S ₅ ). (S ₆ ),
The vehicle brake control device according to any one of claims 1 to 3, further comprising:

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