JP6137890B2 - Vehicle braking device - Google Patents

Description

  The present invention relates to a braking device for a vehicle in which a brake pad operated by an electric parking brake system operated by an electric motor is shared with a brake pad operated by a main brake system operated by a driver's brake pedal operation.

  Conventionally, as a brake device for a vehicle in which a brake pad operated by an electric parking brake system operated by an electric motor is shared with a brake pad operated by a main brake system operated by a driver's brake pedal operation, for example, There is a technique of a disc brake device disclosed in Japanese Unexamined Patent Application Publication No. 2012-127418 (hereinafter, Patent Document 1). The disc brake device includes a brake device that generates a braking force by propelling a piston disposed in a cylinder portion by an electric motor and pressing the friction member against a disc rotor that rotates together with a wheel by the piston. The rigidity corresponding to is acquired, and the thrust of the electric motor is controlled according to the rigidity.

JP 2012-127418 A

  By the way, in the braking device for a vehicle as disclosed in the above-described prior art, the brake pad becomes high temperature by continuous braking by the main brake system, and wear powder of the friction material of the brake pad is generated by this high temperature continuous braking. In addition, there is moisture such as rain water, and there is a problem that when the electric parking brake is operated under the influence of such wear powder and moisture, the fixing force between the brake pad and the disc rotor increases. Furthermore, if the shear stress of the brake pad friction material base itself is reduced due to high-temperature braking, the brake pad remains in the disc rotor even if the electric parking brake is released after the electric parking brake is operated for a long time. The friction material base of the brake pad may be broken. In order to prevent such an increase in the adhesive force between the brake pad and the disc rotor, while trying to improve the brake pad friction material base itself, while maintaining the brake quality so as not to cause brake squeal and judder, etc. It is necessary to change, and it must be disadvantageous in terms of design and cost. In addition, in order to suppress the temperature rise of the brake, it is possible to change the disk rotor type from the solid disk type to the ventilated disk type, but this also increases the cost and increases the weight. is there.

  The present invention has been made in view of the above circumstances, and it is possible to effectively prevent the brake pad and the disk rotor from adhering to each other without changing the current brake configuration and without increasing the cost and weight. An object of the present invention is to provide a braking device for a vehicle.

A vehicle braking apparatus according to an aspect of the present invention includes a main brake system that generates a braking force by pressing a brake pad against a disc rotor from a brake caliper by an operation of a driver's brake pedal, and when a predetermined condition is satisfied. In a vehicle braking apparatus including a parking brake system that generates a braking force by pressing the brake pad against the disc rotor from a brake caliper, the parking brake system selects a parking range, and sets the brake pad in advance. If there is a usage history under high temperature and the gradient of the travel path does not exceed a preset threshold , one parking brake system for the left and right wheels Brake that presses the brake pad against one disc rotor In the N state, the other parking brake system sets the other brake pad to the brake OFF state in which the other brake pad is separated from the other disk rotor, and then sets the brake ON state to press the other brake pad against the other disk rotor. Thereafter, the other parking brake system remains in a brake-on state in which the other brake pad is pressed against the other disk rotor, and the one parking brake system moves the one brake pad to the one disk rotor. After the brake is separated from the disc rotor, the brake ON state in which the one brake pad is pressed against the one disk rotor is repeatedly executed.

  According to the vehicle braking device of the present invention, it is possible to effectively prevent the brake pad and the disk rotor from being firmly fixed without specially changing the configuration of the current brake and without increasing the cost and weight. .

1 is a configuration explanatory diagram of a brake system according to a first embodiment of the present invention. FIG. It is a flowchart of the electric parking brake control program by 1st Embodiment of this invention. It is a flowchart of the electric parking brake control program by the 2nd Embodiment of this invention.

Hereinafter, a first embodiment of the present invention will be described with reference to the drawings.
In FIG. 1, reference numeral 1 denotes a vehicle, and 2FL, 2FR, 2RL, and 2RR denote a left front wheel, a right front wheel, a left rear wheel, and a right rear wheel of the vehicle 1, respectively. The vehicle 1 basically includes a main brake system 20 that generates a braking force based on the depression force of the brake pedal 3 of the driver, and an electric parking brake system 30 that restricts the movement of the vehicle 1 when the vehicle 1 is parked. I have.

  The main brake system 20 generates brake fluid pressure in the master cylinder 4 via a booster (not shown) according to the depression force of the brake pedal 3 by the driver. The brake fluid pressure is introduced into the brake calipers 7FL, 7FR, 7RL, and 7RR of the wheel cylinders 8FL, 8FR, 8RL, and 8RR of the brake devices 6FL, 6FR, 6RL, and 6RR of each wheel through the brake driving unit 5. The brake pads 9FL, 9FR, 9RL, and 9RR are pressed against the disk rotors 10FL, 10FR, 10RL, and 10RR of each wheel to brake each wheel.

  Here, the brake drive unit 5 is composed of a hydraulic unit including a pressurizing source, a pressure reducing valve, a pressure increasing valve, and the like. In addition to the operation of the brake pedal 3 by the driver described above, In response to the control signal, the brake fluid pressure can be independently introduced into each wheel cylinder 8FL, 8FR, 8RL, 8RR of each wheel. Control using brake force such as antilock brake system (Antilock Brake System) to prevent wheel lock and side slip prevention control can be realized.

  On the other hand, in the present embodiment, the electric parking brake system 30 is configured to operate the left and right rear wheel brake devices 6RL, 6RR, and the electric motors 11RL provided in the left and right rear wheel brake devices 6RL, 6RR, 11RR is driven by the parking brake control unit 31 via the motor drive units 12RL and 12RR, respectively, so that the brake calipers 7RL and 7RR of the left and right rear wheel brake devices 6RL and 6RR are moved to the left and right brake pads 9RL and 9RR. The left and right rear wheels 2RL, 2RR are braked by being pressed against the rear wheel disk rotors 10RL, 10RR.

  The parking brake control unit 31 of the electric parking brake system 30 includes an electric parking brake ON / OFF switch 41 that the driver selects and executes ON / OFF of the electric parking brake, and a shift position (drive “D”) selected by the driver. Inhibitor switch 42 for detecting reverse “R”, neutral “N”, parking “P”, etc.), road surface gradient estimating device 43 for estimating road surface gradient θs, and brake pad temperature (for example, A brake pad temperature estimating device 44 (as disclosed in Japanese Patent Laid-Open No. 2005-14692 by the applicant), other sensors, and switches are connected. The parking brake control unit 31 is disclosed in, for example, Japanese Patent Application Laid-Open No. 2010-265793 by the applicant in addition to the on / off of the electric parking brake by the operation of the electric parking brake on / off switch 41 by the driver. In addition, automatic ON / OFF control of the electric parking brake can be executed.

  Further, the parking brake control unit 31 selects the “P” range in accordance with an electric parking brake control program described later, has a use history of the brake pads 9RL and 9RR at a preset high temperature, and the road gradient θs is When the preset threshold value θc (for example, 5%) is not exceeded, the left and right rear wheel brake devices 6RL and 6RR are operated until the preset time Ta elapses after the electric parking brake system 30 is operated. A brake OFF state in which one brake pad 9RR (9RL) is kept pressed to press one disc rotor 10RR (10RL) and the other brake pad 9RL (9RR) is separated from the other disc rotor 10RL (10RR). After the other brake pad 9RL (9RR) After the brake ON state that presses against the disc rotor 10RL (10RR) is set, the other brake pad 9RL (9RR) remains in the brake ON state that presses against the other disc rotor 10RL (10RR), and the one brake pad 9RR (9RL) ) Is set to the brake-off state in which the brake pad 9RR (9RL) is separated from the one disk rotor 10RR (10RL), and the brake-on state in which the one brake pad 9RR (9RL) is pressed against the one disk rotor 10RR (10RL) is repeatedly executed.

  The electric parking brake control program executed by the parking brake control unit 31 will be described with reference to the flowchart of FIG. This electric parking brake control program is executed, for example, when the electric parking brake ON-OFF switch 41 is operated by the driver and the electric parking brake is turned on. In step S101, the brake ON / OFF counter n is cleared (n = 0). This brake ON-OFF counter n is in an ON state after one brake device 6RR (6RL) of the left and right rear wheel brake devices 6RL and 6RR is left in an ON state and the other brake device 6RL (6RR) is in an OFF state. After that, with the other brake device 6RL (6RR) kept in the ON state, the counter is incremented by 1 each time the one brake device 6RR (6RL) is turned off and then turned on once. It has become.

  Next, the process proceeds to S102, where it is determined whether or not the high temperature use condition is satisfied in order to check the use history of the brake pads 6RL and 6RR of the left and right rear wheel brake pads 9RL and 9RR at high temperatures. . Specifically, it is referred to whether or not a history in which the estimated temperature of the brake pads 9RL and 9RR estimated by the brake pad temperature estimation device 44 exceeds, for example, 400 ° C. for 30 minutes or longer is recorded in the memory. Judge by.

  As a result of the determination in S102, if there is a usage history of the brake pads 9RL and 6RR of the left and right rear wheel brake devices 9RL and 9RR at a high temperature, the process proceeds to S103.

  In S103, it is determined whether or not the “P” range is selected. If the “P” range is selected, the process proceeds to S104.

  In S104, it is determined whether the road surface gradient θs does not exceed a preset threshold value θc (for example, 5%) (θs <θc). If θs <θc, the process proceeds to S105.

  That is, the determination of S102 to S104 described above is a determination of an execution condition for executing the subsequent sticking prevention process of the electric parking brake system 30, and if any one of the determinations of S102 to S104 cannot be satisfied ( If the high temperature use condition is not satisfied in S102, or if the “P” range is not selected in S103, or if θs ≧ θc in S104), the program exits as it is.

  When all the above determinations of S102 to S104 are satisfied and the process proceeds to S105, an elapsed time t after the electric parking brake system 30 is operated is determined whether or not a preset time Ta has elapsed. When t <Ta and the preset time Ta has not elapsed since the electric parking brake system 30 was operated, the sticking prevention processing of the electric parking brake system 30 after S106 is performed. On the other hand, if t ≧ Ta and the electric parking brake system 30 has been operated for a preset time Ta or more, it is determined that the sticking prevention processing of the electric parking brake system 30 has been sufficiently performed. And exit the program. Thus, the determination in S105 is a determination of an end condition.

  When it is determined in S105 that t <Ta and the process proceeds to S106, the elapsed time t after the electric parking brake system 30 is operated is tc · n (: tc is one of the brake devices 6RL and 6RR for the left and right rear wheels. The brake device 6RR (6RL) is left in the ON state, the other brake device 6RL (6RR) is turned off and then turned on, and then the other brake device 6RL (6RR) is left in the ON state. It is determined whether or not the brake device 6RR (6RL) has reached (t = tc · n).

  If t = tc · n is not determined as a result of the determination in S106, the processing from S105 is repeated, and if t = tc · n, the process proceeds to S107 and the brake device for the right rear wheel is set. The brake pad 9RR of the left rear wheel is set to the brake OFF state in which the brake pad 9RL of the left rear wheel is separated from the disk rotor 10RL while the brake pad 9RR of the 6RR is pressed against the disc rotor 10RR. The brake is pressed to press the disc rotor 10RL.

  Next, the process proceeds to S108, the brake pad 9RL of the left rear wheel brake device 6RL is pressed against the disc rotor 10RL, and the brake pad 9RR of the right rear wheel brake device 6RR is separated from the disc rotor 10RR. An OFF state is set, and immediately after that, a brake ON state in which the brake pad 9RR is pressed against the disc rotor 10RR is set.

  In S109, the brake ON-OFF counter n is incremented by 1 (n = n + 1), and the processing from S105 is repeated.

  Thus, according to the first embodiment of the present invention, the parking brake control unit 31 selects the “P” range, has a use history of the brake pads 9RL and 9RR at a preset high temperature, and When the road surface gradient θs does not exceed a preset threshold value θc (for example, 5%), the brakes for the left and right rear wheels are applied until a preset time Ta elapses after the electric parking brake system 30 is operated. One brake device 6RR (6RL) of the devices 6RL and 6RR is kept in the ON state, the other brake device 6RL (6RR) is turned off and then turned on, and then the other brake device 6RL (6RR) is turned on. Since it is repeatedly in the state of being turned on after one brake device 6RR (6RL) is turned off, the electric parking Even if the brake system 30 is operated, the brake pad 9RL (9RR) and the disc rotor 10RL (10RR) are effectively prevented from sticking to each other. Further, since the configuration of the present invention can be performed only by control change, it can be realized without causing problems such as design change, cost increase, and weight increase. Furthermore, since the OFF time of one or the other brake device according to the first embodiment can be realized short, the braking force of the parking brake control unit 31 is sufficiently maintained.

  Next, FIG. 3 shows a flowchart of an electric parking brake control program executed by the parking brake control unit 31 according to the second embodiment of the present invention. In the electric parking brake control according to the second embodiment, one brake device 6RR (6RL) of the left and right rear wheel brake devices 6RL and 6RR is left in the ON state, and the other brake device 6RL (6RR) is set in the OFF state. After the ON state is turned on, the other brake device 6RL (6RR) remains in the ON state, and when the one brake device 6RR (6RL) is turned OFF and then turned ON, the OFF state Unlike the first embodiment, the configuration and operation are the same as those of the first embodiment, and the same components and processes are denoted by the same reference numerals, and the description thereof is omitted.

  That is, the flowchart of FIG. 3 corresponds to the flowchart of FIG. 2 of the first embodiment. If t = tc · n is not satisfied as a result of the determination in S106, the processing from S105 is repeated, and t If t = tc · n, the routine proceeds to S201, where the brake pad 9RR of the right rear wheel brake device 6RR is pressed against the disc rotor 10RR, and the brake device 6RL of the left rear wheel is maintained. The brake pad 9RL is brought into a brake OFF state in which the brake pad 9RL is separated from the disc rotor 10RL.

  Then, the process proceeds to S202, and whether or not half of the time necessary to increase the counter n by 1, that is, the time corresponding to “0.5” of the counter has passed (t = tc · (n + 0.5)). Determined. When the time corresponding to “0.5” of the counter has elapsed in S202 and the time corresponding to “0.5” of the counter has elapsed, that is, the brake device 6RL for the left rear wheel is turned off. When the time to be in the state becomes a time corresponding to “0.5” of the counter, the process proceeds to S203 and the brake device 6RL for the left rear wheel is turned on.

  Next, in S204, the brake pad 9RL of the brake device 6RL for the left rear wheel is kept in the brake-on state to press the disc rotor 10RL, and the brake pad 9RR of the brake device 6RR for the right rear wheel is separated from the disc rotor 10RR. Set to OFF state.

  Then, the process proceeds to S205, and from S203, half of the time necessary to increase the counter n by 1, that is, a time corresponding to “0.5” of the counter has passed (t = tc · (n + 1)). Is determined. If the time corresponding to “0.5” of the counter has elapsed in S205 and the time corresponding to “0.5” of the counter has elapsed, that is, the brake device 6RR for the right rear wheel is turned off. When the time to keep the state becomes the time corresponding to “0.5” of the counter, the process proceeds to S206, and the brake device 6RR for the right rear wheel is turned on.

  In step S207, the brake ON-OFF counter n is incremented by 1 (n = n + 1), and the processing from step S105 is repeated.

  As described above, according to the second embodiment of the present invention, as in the first embodiment, the parking brake control unit 31 selects the “P” range and sets the brake pads 9RL and 9RR at a preset high temperature. If the road surface gradient θs does not exceed a preset threshold value θc (for example, 5%), a preset time Ta has elapsed since the electric parking brake system 30 was activated. Until one brake device 6RR (6RL) of the left and right rear wheel brake devices 6RL and 6RR remains in an ON state until the other brake device 6RL (6RR) is turned off and then turned on. The brake device 6RL (6RR) is kept in the ON state, and one brake device 6RR (6RL) is repeatedly turned off after being turned off. Therefore, even if the electric parking brake system 30 is operated, the brake pad 9RL (9RR) and the disc rotor 10RL (10RR) are effectively prevented from sticking to each other. Further, since the configuration of the present invention can be performed only by control change, it can be realized without causing problems such as design change, cost increase, and weight increase.

  Further, in the second embodiment, one brake device 6RR (6RL) of the left and right rear wheel brake devices 6RL and 6RR is kept in the ON state, and the other brake device 6RL (6RR) is turned off and then turned on. After setting the state, the other brake device 6RL (6RR) is left in the ON state, and when the one brake device 6RR (6RL) is repeatedly turned off and then turned on, the time for turning it off is repeated. Since the setting is made long, it is more effectively prevented that the brake pad 9RL (9RR) and the disc rotor 10RL (10RR) are fixed.

  In each of the embodiments of the present invention, the brake device 6RR for the right rear wheel is left in the ON state, the brake device 6RL for the left rear wheel is turned off and then turned on, and then the left rear wheel is turned on. The order in which the brake device 6RL is kept in the ON state and the right rear wheel brake device 6RR is in the OFF state after the brake device 6RR is in the ON state is illustrated, but the order is reversed as indicated by the parentheses in the description. Also good.

DESCRIPTION OF SYMBOLS 1 Vehicle 2FL, 2FR, 2RL, 2RR Wheel 3 Brake pedal 4 Master cylinder 5 Brake drive part 6FL, 6FR, 6RL, 6RR Brake device 7FL, 7FR, 7RL, 7RR Brake caliper 8FL, 8FR, 8RL, 8RR Wheel cylinder 9FL, 9FR , 9RL, 9RR Brake pad 10FL, 10FR, 10RL, 10RR Disc rotor 11RL, 11RR Electric motor 12RL, 12RR Motor drive unit 20 Main brake system 21 Main brake control unit 30 Electric parking brake system 31 Parking brake control unit 41 Electric parking brake ON -OFF switch 42 Inhibitor switch 43 Road surface slope estimation device 44 Brake pad temperature estimation device

Claims (3)

A main brake system that generates a braking force by pressing the brake pad from the brake caliper to the disc rotor by operating the brake pedal of the driver, and pressing the brake pad from the brake caliper to the disc rotor when a predetermined condition is satisfied A braking device for a vehicle having a parking brake system for generating braking force
The parking brake system is preset when a parking range is selected, the brake pad has a usage history under a preset high temperature, and the gradient of the travel path does not exceed a preset threshold. Until the condition is satisfied, one parking brake system of the left and right wheels remains in a brake-on state in which one brake pad is pressed against one disk rotor, and the other parking brake system holds the other brake pad on the other disk. After the brake OFF state, which is separated from the rotor, is set to the brake ON state in which the other brake pad is pressed against the other disk rotor, the other parking brake system is configured such that the other brake pad is set to the other disk rotor. While the brake is pressed Then, the one parking brake system sets the one brake pad to a brake OFF state in which the one brake pad is pressed against the one disk rotor after the one brake pad is set to a brake OFF state that separates from the one disk rotor. A vehicle braking device characterized by repeatedly executing the above. Exit conditions set above in advance, the vehicle according to claim 1, wherein determining that the termination condition when the parking brake system has exceeded the time set in advance since the operation has been established Braking device. 3. The vehicle according to claim 1 , wherein the brake OFF state is continued until a preset time elapses in one of the one brake system and the other brake system. Braking device.

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