JP4012397B2 - Brake device for vehicle - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention is for a vehicle that applies a braking force to a brake portion provided in a vehicle by causing an electric motor to rotate forward in accordance with an operating force of a brake pedal to generate an oil pressure in a master cylinder that is a hydraulic source. it relates to the brake equipment.
[0002]
[Prior art]
As a brake device for a vehicle such as an automobile, a disc brake device, a drum brake device, and the like are common. Many of these brake devices are mainly hydraulic. For example, in the case of a hydraulic disc brake device, when the brake pedal is depressed, the pedal force is transmitted to the piston of the master cylinder, and the disc-like brake disc that rotates with the axle by the hydraulic pressure generated at that time is held between the brake pads. Is done. As a result, a braking force is generated. Usually, a booster (brake booster) is used to operate the master cylinder with a small pedal effort. With this booster, a large braking force can be obtained with a small pedal effort.
[0003]
In this type of brake device, there is a case where the brake disk is shaken or deformed when the vehicle is traveling. At this time, the caliper piston for moving the brake pad toward and away from the brake disk is pushed back, and the brake pedal depression stroke amount is greatly increased during braking. That is, a so-called “Knock Back” occurs in which the brake pad is separated from the brake disc more than a specified amount. Then, as shown in FIG. 5, when the brake pedal reaches the stroke end on the depression side, the occurrence of knockback is transmitted to the driver. Specifically, the brake pedal hits the floor of the vehicle. Incidentally, when knockback occurs, the driver recovers the braking force by instantaneously repressurizing the brake pedal (depressing it again).
[0004]
Incidentally, in addition to the above-described hydraulic disc brake device, a hydraulic intervening electric brake device is known. In this type of electric brake device, an electric motor is used instead of the booster used in the hydraulic disc brake device. The reason for using the electric motor is to enable various types of brake control by converting the stroke amount of the brake pedal into an electric signal by a stroke simulator. In addition to the function of converting the brake pedal brake pedal force into an electrical signal as described above, the stroke simulator also has a function of simulating the amount of oil consumed to eliminate the uncomfortable feeling when the brake pedal is depressed. ing.
[0005]
[Problems to be solved by the invention]
However, since the hydraulic intervening electric brake device uses a stroke simulator along with the use of the electric motor, even if knockback occurs as shown in FIG. 6, the brake pedal reaches the depression side stroke end. There is no. This means that the driver is less aware that knockback has occurred. Therefore, it is difficult to obtain a large braking force even though a feeling of pedaling force is continuously applied to the brake pedal by the electric motor and the stroke simulator.
[0006]
The present invention has been made paying attention to such problems existing in the prior art. An object of the present invention is to provide a vehicle brake device that can recover braking force by automatically detecting that knockback has occurred .
[0007]
[Means for Solving the Problems]
(Invention of Claim 1)
In the first aspect of the invention, the braking force is applied to the brake portion provided in the vehicle by causing the electric motor to rotate forward in accordance with the operating force of the brake pedal to generate an oil pressure in the master cylinder that is a hydraulic power source. In the vehicular brake device, the braking state detecting means for detecting the braking state of the vehicle, the motor driving state detecting means for detecting the driving state of the electric motor, and the detection result detected by the braking state detecting means Is a knockback determination means for determining whether or not the detection result detected by the motor drive state detection means is suitable, and a motor control for driving and controlling the electric motor based on the determination result of the knockback determination means and means, the brake state detecting means is a hydraulic force sensor for detecting the oil pressure of the hydraulic path including said hydraulic pressure source, the The motor drive state detection means is a motor rotation amount detection sensor that detects the rotation amount of the electric motor, and when the knockback determination means determines that the knockback has occurred, the motor control means The gist is to reversely rotate in the opposite direction and then rotate the electric motor in the same direction as that during braking .
[0008]
Here, “the operating force of the brake pedal” includes both the stepping force when the brake pedal is operated or the stepping stroke amount (stepping amount) when the brake pedal is operated.
[0009]
According to this invention, the braking state of the vehicle is detected by the braking state detection means, and the driving state of the electric motor is detected by the motor driving state detection means. If the braking state of the vehicle does not match the driving state of the electric motor, the knockback determination means determines that knockback has occurred in the brake unit. Based on this determination result, the drive of the electric motor is controlled by the motor control means, so that the knockback of the brake portion is eliminated. Moreover, the driver does not need to depress the brake pedal, and can keep the brake pedal depressed. In other words, there is no need for an operation for eliminating the knockback, and there is no burden on the driver of the vehicle.
[0011]
Further, the knockback determination means uses whether or not the hydraulic pressure in the hydraulic path according to the driving state of the electric motor is within a specified range as a determination criterion for knockback. Therefore, it is possible to accurately determine knockback by detecting the hydraulic pressure in the hydraulic path that directly affects the braking force. Further, the knockback determination means uses whether or not the hydraulic pressure of the hydraulic path according to the rotation amount of the electric motor is within a specified range as a knockback determination criterion. Therefore, knockback can be determined more accurately by detecting the rotation amount of the electric motor that directly affects the control of the braking force. In addition, since the knockback of the brake unit can be easily eliminated simply by controlling the rotation direction of the electric motor, the mechanical structure of the vehicle brake device can be reduced without complicating and increasing the size. It becomes possible.
[0012]
(Invention of Claim 2 )
In the invention described in claim 2, in the vehicle braking apparatus according to claim 1, wherein the motor control means, the reverse rotation of the electric motor, from the amount of rotation rotates forward until before it is determined that the knock-back The main point is to increase the
[0013]
According to the present invention, when it is determined that knockback has occurred in the brake portion, the electric motor is reversely rotated, but the amount of rotation is larger than the amount of rotation that has been normally rotated until it is determined that knockback has occurred. Therefore, the hydraulic pressure in the hydraulic path including the hydraulic power source can be reliably restored. Therefore, knockback can be reliably eliminated.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment in which a vehicle brake device of the present invention is embodied in a disk type will be described with reference to the drawings.
[0021]
As shown in FIG. 1, the brake unit 12 of the vehicle brake device 11 includes a brake caliper 14. The brake caliper 14 is provided with a brake pad (not shown), and the brake pad is arranged to be opposed to and separated from the outer side surface and the inner side surface of the disc-like brake disc 16 fixed to the axle 15.
[0022]
The brake caliper 14 is movable along the axial direction of the axle 15 by the hydraulic pressure generated by the master cylinder 20. When the inner brake pad is brought into pressure contact with the brake disc 16 by the operation of the master cylinder 20, the brake caliper 14 moves to the inner side along the axial direction by the reaction force generated at that time, so that the outer brake pad is also Press contact with the brake disc 16. Thereby, a braking force is generated in the brake unit 12.
[0023]
The master cylinder 20 is operated by an electric motor (brushless motor) 22 that can be rotated in the forward direction or the reverse direction in accordance with the operation of the brake pedal 21. The electric motor 22 has a role of operating the master cylinder 20 with a small pedal effort. That is, the electric motor 22 applies a large braking force to the brake unit 12 with a small pedal effort.
[0024]
Next, the electrical configuration of the vehicle brake device 11 will be described.
As shown in FIG. 1, the vehicle brake device 11 is provided with a controller 25 for controlling it. The controller 25 includes a ROM 26 as a recording medium, a RAM 27 as a storage unit, and a CPU 28. The ROM 26 stores a control program necessary for controlling the electric motor 22. The RAM 27 temporarily stores data and the like obtained with the execution of the control program. Further, the CPU 28 reads the control program from the ROM 26 and executes it.
[0025]
The stroke simulator 30 connected to the brake pedal 21 detects the stroke amount of the brake pedal 21 and outputs the stroke amount detection signal to the CPU 28. Then, according to the stroke amount detected by the stroke simulator 30, the CPU 28 determines the rotation amount of the electric motor 22 and outputs a motor rotation amount instruction signal to the electric motor 22. Instead of detecting the stroke amount of the brake pedal 21, it is also possible to detect the depression force of the brake pedal 21 and output it to the CPU 28.
[0026]
The electric motor 22 is provided with a motor rotation amount detection sensor 31 for detecting the rotation amount, and the detection sensor 31 outputs a rotation amount detection signal to the CPU 28. The master cylinder 20 is provided with an oil pressure detection sensor 32 for detecting the oil pressure in the hydraulic path 33 including the master cylinder 20, and the oil pressure detection sensor 32 outputs an oil pressure detection signal to the CPU 28.
[0027]
The RAM 27 stores characteristic data (characteristic map) D between the motor rotation amount and the hydraulic pressure shown in FIG. On the vertical axis of the characteristic data D, the oil pressure value of the master cylinder 20 is set. On the other hand, the rotation amount of the electric motor 22 is set on the horizontal axis of the characteristic data D. Then, the CPU 28 determines whether or not an oil pressure suitable for the rotation amount of the electric motor 22 is generated in the hydraulic path 33 with reference to the characteristic data D.
[0028]
Next, the operation of the vehicle brake device 11 configured as described above will be described based on the flowchart shown in FIG. 3 and the timing chart shown in FIG. This operation proceeds under the control of the CPU 28 based on the control program stored in the ROM 26.
[0029]
(Steps S1, S2)
When the brake pedal 21 is depressed by the driver at the timing T <b> 1, the stroke amount is detected by the stroke simulator 30. Then, the CPU 28 determines a rotation amount instruction value of the electric motor 22 according to the stroke amount of the brake pedal 21 and rotates the electric motor 22 in the normal direction according to the instruction value.
[0030]
(Steps S3 and S4)
Then, the CPU 28 determines whether the hydraulic value of the master cylinder 20 is suitable for the motor rotation amount based on the characteristic data of the motor rotation amount and the hydraulic pressure shown in FIG. At timing T2, when the electric motor 22 is rotating forward, if the hydraulic value of the master cylinder 20 does not match the amount of motor rotation, the CPU 28 determines that knockback has occurred in the brake unit 12. The knockback is a phenomenon in which the stroke of the brake pedal 21 is greatly increased during braking because a caliper piston (not shown) provided in the brake caliper 14 is pushed back due to the deflection or deformation of the brake disc 16.
[0031]
(Step S5)
Based on the determination result, the CPU 28 instantaneously reverses the electric motor 22 by a predetermined amount. Incidentally, it takes time to reversely rotate the electric motor 22 from the operation time (between T1 and T2) from when the electric motor 22 first starts to rotate forward by the depression operation of the brake pedal 21 until it is determined to be knockback. The operation time (between T3 and T4) is shorter. Further, the reverse rotation amount of the electric motor 22 is larger than the normal rotation amount from when the electric motor 22 first starts to rotate forward by the depression operation of the brake pedal 21 until it is determined that the knockback is made.
[0032]
(Step S6)
When the reverse rotation of the electric motor 22 is completed, the CPU 28 rotates the electric motor 22 forward again at the timing T3. At this time, a gap between the pad provided on the brake caliper 14 and the brake disk 16, that is, a so-called pad clearance starts to narrow. Note that the operation time during which the electric motor 22 is rotated forward again is substantially the same as the operation time during the reverse rotation, and is extremely short. The reason why the operation time required to reversely rotate the electric motor 22 and the operation time required to rotate the electric motor 22 again after the knockback is determined is set to a short time is that the braking force is applied to the brake unit 12. This is in order to shorten the time required.
[0033]
Then, at timing T4, when the amount of rotation when it is assumed that knockback has not occurred before the electric motor 22 reaches the rotation amount instruction value, the hydraulic pressure of the master cylinder 20 suddenly increases, and normal oil Start to return to pressure. Here, the rotation amount of the electric motor 22 at the timing T4 indicates the motor rotation amount corresponding to the extension line of the timing T2 in the graph of the rotation amount of the electric motor 22 shown in FIG. Then, when the hydraulic pressure in the hydraulic path 33 returns to a normal value, braking force starts to be applied to the brake unit 12. In addition, after the electric motor 22 is rotated forward again, the processes in steps S3 and S4 described above are repeated.
[0034]
(Step 7)
Thereafter, when the rotation amount of the electric motor 22 coincides with the rotation amount instruction value set by the depression operation of the brake pedal 21 at the timing T5, the CPU 28 holds the torque of the electric motor 22. As a result, the hydraulic pressure in the hydraulic path 33 including the master cylinder 20 reaches the target value, and a braking force is applied to the brake unit 12.
[0035]
Therefore, according to the present embodiment, the following effects can be obtained.
(1) By determining whether or not the braking state of the vehicle and the driving state of the electric motor 22 are compatible, it is possible to automatically determine whether or not the brake unit 12 is knocked back. . And when it determines with a knockback, the rotation of the electric motor 22 is drive-controlled, and the knockback of the brake part 12 can be eliminated automatically.
[0036]
(2) Moreover, even if the knockback is determined, the driver does not need to depress the brake pedal. In short, since the driver does not need to perform an operation for eliminating the knockback, the operation burden on the driver can be reduced.
[0037]
(3) The oil pressure detection sensor 32 detects the hydraulic path 33 including the master cylinder 20 as the vehicle braking state. Further, the rotation amount of the electric motor 22 is detected by a motor rotation amount detection sensor 31. Whether or not an oil pressure corresponding to the amount of rotation of the electric motor 22 is generated in the hydraulic path 33 is used as a determination criterion for knockback. That is, the criterion for knockback is to detect an element that directly affects the braking force of the brake unit 12, that is, the oil pressure in the hydraulic path 33. Therefore, the pedal force is always applied to the brake pedal 21 as in the vehicle brake device 11 in the present embodiment, and the knockback can be accurately determined even if it is difficult to recognize that the knockback has occurred.
[0038]
(4) Even when knockback occurs, the electric pedal continues to provide a feeling of pedaling force to the brake pedal, so that the knockback can be eliminated without giving the driver a sense of incongruity.
[0039]
(5) When the electric motor 22 is reversely rotated and forwardly rotated again after the knockback is determined, the operating time of the electric motor 22 is set to be extremely short by rapidly rotating the electric motor 22. Thereby, the knockback of the brake part 12 can be eliminated instantaneously.
[0040]
(6) A simple method of controlling the rotation of the electric motor 22 is used to eliminate the knockback that occurs in the brake unit 12. Therefore, since it is not necessary to change the structure of the vehicle brake device 11 significantly, it is possible to prevent the structure of the vehicle brake device 11 from becoming complicated and large. Accordingly, the cost of the vehicle brake device 11 can be prevented from increasing.
[0041]
(7) If it is determined that the brake unit 12 is knocked back, the amount of rotation that reversely rotates the electric motor 22 is set to be larger than the amount of rotation that is rotated forward until it is determined that knockback. Therefore, the hydraulic pressure in the hydraulic path 33 including the master cylinder 20 can be reliably restored. Therefore, knockback can be reliably eliminated.
[0042]
(Another embodiment)
The embodiment of the present invention may be modified as follows.
The vehicle brake device 11 of the above embodiment is embodied as a disc brake type, but may be embodied as a drum brake type.
[0043]
In the above embodiment, the master cylinder 20 is used as a hydraulic pressure generation source for driving the brake caliper 14, but other than this, for example, an electric hydraulic pump or the like may be used.
[0044]
In the embodiment described above, it is determined whether or not the hydraulic pressure in the hydraulic path 33 generated by the master cylinder 20 is suitable for the rotation amount of the electric motor 22 to determine that the brake unit 12 is knocked back. . In addition to the oil pressure, a change in the pressure of the brake pad against the brake disc 16, the braking torque of the axle 15, or the wheel speed may be used as a knockback determination factor. Furthermore, the knockback is determined by combining two or more determination elements among the knockback determination elements such as the hydraulic pressure of the hydraulic path 33, the pressure contact force of the brake pad, the braking torque of the axle 15, or the wheel speed. May be.
[0045]
In the above-described embodiment, the knockback is determined based on whether or not the hydraulic pressure generated by the master cylinder 20 matches the rotation amount of the electric motor 22. Instead of the rotation amount of the electric motor 22, the drive pulse may be changed. A drive pulse refers to a rectangular wave that is sent in response to an encoder signal of each phase.
[0046]
The electric motor 22 may be any type of a three-phase motor or a single-phase motor.
Next, the technical idea grasped by the previous mentioned with the embodiments below.
(1) pre-Symbol braking state detecting means is a pad contact pressure sensor for detecting the pressing force of the brake pad provided on the brake unit 12 is pressed against the brake disc.
[0047]
(2) pre-Symbol braking state detecting means is a braking force sensor for detecting the brake torque axle.
(3) pre-Symbol braking state detecting means is a wheel speed sensor for detecting a wheel speed of the vehicle.
[0048]
(4) before SL motor driving state detecting means is a driving pulse sensor for detecting a driving pulse of the electric motor.
(5) Based on an electric motor for driving a piston provided in a master cylinder that generates hydraulic pressure, a stroke detection means for detecting the amount of depression of the brake pedal, and a detection signal detected by the stroke detection means Control means for driving and controlling the electric motor, and in the vehicle brake device for applying a braking force to the brake portion of the vehicle by generating an oil pressure in the master cylinder by the electric motor, the hydraulic pressure including the master cylinder An oil pressure detection sensor for detecting the hydraulic pressure of the path, a motor rotation amount detection sensor for detecting the rotation amount of the electric motor, and an oil pressure detected by the oil pressure detection sensor are detected by the motor rotation amount detection sensor. Knockback determination means for determining whether the rotation amount of the electric motor is suitable When the knockback is determined by the knockback determination means, the motor control means rotates the electric motor in the direction opposite to that during braking, and then rotates the electric motor again in the rotation direction during braking. A brake device for a vehicle.
[0049]
(6) A vehicular brake device that applies a braking force to a brake portion provided in a vehicle by generating an oil pressure in a master cylinder with an electric motor according to a depression stroke amount of a brake pedal. In the method of eliminating the knockback generated in the brake unit, the hydraulic pressure of the hydraulic path including the master cylinder is detected by an oil pressure detection sensor, the rotation amount of the electric motor is detected by the motor rotation amount detection sensor, and the hydraulic path If the hydraulic pressure of the motor does not match the amount of rotation of the electric motor, it is determined that knockback has occurred in the brake unit, and based on the determination result, the electric motor is rotated in the opposite direction to that during braking. After that, the knockback of the brake unit is eliminated by rotating the electric motor in the same direction as when braking again. A knockback elimination method for a vehicle brake device.
[0050]
(7) A vehicular brake device that applies a braking force to a brake portion provided in a vehicle by generating an oil pressure in a hydraulic pressure source with an electric motor in accordance with an operation force of a brake pedal. In the method of detecting a knockback generated in the vehicle, the braking state of the vehicle is detected by a braking state detection unit, the driving state of the electric motor is detected by a motor driving state detection unit, and the braking state of the vehicle is driven by the electric motor. If it is not suitable for a state, it will determine with the brake part having knocked back, The knock-back detection method of the brake device for vehicles characterized by the above-mentioned.
[0051]
(8) A vehicular brake device that applies a braking force to a brake portion provided in a vehicle by generating an oil pressure in a master cylinder with an electric motor in accordance with a depression amount of a brake pedal. In the method of detecting the knockback generated in the section, the hydraulic pressure of the hydraulic path including the master cylinder is detected by an oil pressure detection sensor, the rotation amount of the electric motor is detected by the motor rotation amount detection sensor, and the hydraulic path of the hydraulic path is detected. A knockback detection method for a vehicle brake device, characterized in that if the hydraulic pressure does not match the amount of rotation of the electric motor, it is determined that knockback has occurred in the brake portion.
[0052]
(9) A vehicular brake device that applies a braking force to a brake portion provided in a vehicle by generating an oil pressure in a hydraulic pressure source with an electric motor in accordance with an operation force of a brake pedal, In a knockback detection device for detecting a knockback generated in a section, a braking state detection unit that detects a braking state of the vehicle, a motor driving state detection unit that detects a driving state of the electric motor, and the braking state detection unit Knockback detection for a vehicle brake device, comprising: a knockback determination means for determining whether or not a detection result detected matches a detection result detected by the motor drive state detection means. apparatus.
[0053]
【The invention's effect】
According to the first aspect of the present invention, the braking force of the brake part can be recovered by automatically detecting that knockback has occurred in the brake part.
[0054]
Further, it is possible to more accurately determine knockback occurring in the brake portion. In addition, since the structure of the vehicle brake device is not complicated and does not increase in size, the cost can be reduced.
According to the second aspect of the present invention, it is possible to reliably eliminate knockback that occurs in the brake portion.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of a vehicle brake device according to an embodiment.
FIG. 2 is characteristic data showing the relationship between the rotation amount of the electric motor and the hydraulic pressure in the hydraulic path.
FIG. 3 is a flowchart showing the operation of the vehicle brake device.
FIG. 4 is a timing chart showing the operation of the vehicle brake device.
FIG. 5 is a timing chart of a vehicular brake device according to a conventional technique.
FIG. 6 is a timing chart of a vehicle brake device showing a different type of prior art from FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 11 ... Brake apparatus for vehicles, 12 ... Brake part, 20 ... Master cylinder (hydraulic pressure source), 21 ... Brake pedal, 22 ... Electric motor, 28 ... CPU (motor control means, knockback determination means), 32 ... Oil pressure detection Sensor (braking state detection means) 31 ... Motor rotation amount detection sensor (motor driving state detection means), 33 ... hydraulic path.

Claims (2)

In a vehicle brake device that applies a braking force to a brake portion provided in a vehicle by causing an electric motor to rotate forward in accordance with an operation force of a brake pedal to generate an oil pressure in a master cylinder that is a hydraulic source.
Braking state detecting means for detecting the braking state of the vehicle;
Motor driving state detecting means for detecting the driving state of the electric motor;
Knockback determination means for determining whether the detection result detected by the braking state detection means is compatible with the detection result detected by the motor drive state detection means;
Motor control means for driving and controlling the electric motor based on the determination result of the knockback determination means ,
The braking state detection means is an oil pressure detection sensor that detects an oil pressure of a hydraulic path including the hydraulic pressure source, and the motor drive state detection means is a motor rotation amount detection sensor that detects the rotation amount of the electric motor. ,
When it is determined that the knockback is determined by the knockback determination means, the motor control means reversely rotates the electric motor in the direction opposite to that during braking, and then rotates the electric motor in the same direction as that during braking again. A brake device for a vehicle. 2. The vehicle brake device according to claim 1, wherein the motor control unit increases a reverse rotation amount of the electric motor to be larger than a rotation amount that has been normally rotated before it is determined to be knockback . 3.

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