JP2004268703A - Brake squeak control device for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a brake squeak control device for performing a prescribed control for a squeak control by specifying traveling state and temperature condition easy to actually generate brake noise. <P>SOLUTION: This brake squeak control device transmits detection signals from a sensor group for showing the traveling state of a vehicle from a tread force sensor 11 and wheel speed sensors 12 (12a to 12d) and a sensor group for showing temperature states from a temperature sensor 15 of cooling water of an engine E/G, a cabin temperature sensor 13 and an outside air temperature sensor 14 to a control circuit 20. When conditions corresponding to a cold state and an early morning state are detected by a calculation within the control circuit 20, an opening/closing control is performed for a solenoid valve 3b to suppress brake squeak. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a vehicle brake squeal control device that suppresses a so-called squeal phenomenon that occurs during braking of a vehicle such as an automobile.
[0002]
[Prior art]
The so-called brake squeal phenomenon that occurs at the time of braking by a vehicle brake includes various vibration frequencies ranging from a relatively low frequency sound called a grone to a sound that can be heard as a squeal and squeal in a high frequency band of several KHz or more. Various measures have been conventionally proposed to eliminate or reduce noise. As one example, a vehicular braking device in which measures for preventing a brake squeal phenomenon described in Patent Document 1 are taken is known. The countermeasure according to Patent Literature 1 is to attach vibration detecting means for detecting vibration by a piezoelectric effect of a piezoelectric element and vibrating means for attenuating the detected vibration by an inverse piezoelectric effect of the piezoelectric element to a friction member of a brake to reduce the vibration. It is to prevent and eliminate brake squeal.
[0003]
As another example, a brake control device disclosed in Patent Literature 2 is known, and the control device includes a control unit that generates a braking force according to a detection signal from a sensor that detects a depression force on a brake pedal, When the speed of the vehicle becomes equal to or lower than a predetermined speed during the braking operation, the braking force of the brake device is changed in a predetermined cycle to suppress the resonance of each component of the brake device.
[0004]
Further, as a new example, a brake noise prevention device disclosed in Patent Document 3 is known. This device detects the brake torque and caliper vibration during the operation of the brakes while traveling at a predetermined speed or less, and when these values exceed a predetermined value and detects the occurrence of noise, opens the valve provided between the brake device and the reservoir and brakes. The pressure is reduced, or a valve provided between the brake device and the pressure accumulation source is opened to increase the brake pressure to prevent noise.
[0005]
[Patent Document 1]
JP-A-4-54325 [Patent Document 2]
JP-A-11-278229 [Patent Document 3]
Japanese Patent Application Laid-Open No. 2000-344072
[Problems to be solved by the invention]
By the way, the brake squeal phenomenon involves complicated factors, and it is necessary to fundamentally elucidate the cause of the squeal.However, despite various proposals in the above-mentioned prior patent documents, it is still fundamental. Factors have not been clarified or resolved. In the brake squeal phenomenon, the squeal in a specific frequency band (7 to 9 KHz) is large, and it is said that rigid body vibration and bending vibration coexist. This is particularly annoying for a driver, but such noise is generated when braking with a brake. It has been empirically known that it does not occur at all times, but tends to occur at cold start or the first start in the morning.
[0007]
However, in any of the braking devices or the control devices of Patent Documents 1 to 3 described above, under what conditions such a brake squeal phenomenon is likely to occur, little is taken into consideration. It is not a squeal suppression measure. For example, Patent Literature 1 discloses a method in which vibration is detected by a piezoelectric element and the vibration is canceled out by the inverse piezoelectric effect of the piezoelectric element of the vibrating means, and the temperature, braking force, rotation speed, and the like when a brake noise occurs. It is necessary to operate the apparatus continuously during traveling so as to always detect the vibration regardless of the conditions.
[0008]
In addition, the detection capability of sensing the vibration of the piezoelectric element is not uniform over all frequencies, and may not respond in a specific frequency band. The brake control device disclosed in Patent Literature 2 only suppresses the resonance state only under the condition of the vehicle speed equal to or lower than the predetermined speed and the braking force, and does not consider other conditions such as the temperature condition and the running time at all. Further, the squeal phenomenon cannot be suppressed efficiently only by suppressing the resonance state.
[0009]
The brake noise prevention device of Patent Document 3 also performs noise prevention only by the caliper vibration exceeding a predetermined value and the vehicle speed below a predetermined speed, and the condition of decreasing or increasing the brake pressure, and the noise prevention measures are the same as in the case of Patent Document 2. Is not enough. In addition, brake squeal may occur not only at the time of forward movement but also at the time of reverse movement, and there is no example that considers this.
[0010]
The present invention, noting the above-described problem, does not control the noise suppression only by detecting a state that does not necessarily match the actual brake noise generation condition of detecting the caliper vibration or detecting a vehicle speed below a predetermined value. It is another object of the present invention to provide a brake squeal control device that specifies a running state and a temperature condition in which brake noise is likely to actually occur and performs predetermined control for squeal control.
[0011]
It is another object of the present invention to provide a brake squeal control device that performs control for suppressing the occurrence of brake noise during reverse travel.
[0012]
[Means for Solving the Problems]
The present invention solves the above-described problems by providing a predetermined cold state and a first morning state when the time, running state, and temperature conditions are within predetermined ranges after the start switch of the vehicle is turned on. Is detected by a sensor signal and a clock signal, the brake squeal control device suppresses brake squeal by controlling the pressing force of the brake means.
[0013]
According to the brake squeal control device of the present invention having the above-described configuration, when the predetermined cold state and the first morning state are detected by the signals of the sensor and the clock representing these conditions, the control of the pressing force of the brake means is performed. By doing so, brake squeal control is performed. Therefore, the brake squeal control is performed regardless of whether or not the brake squeal phenomenon actually occurs. It is said that the brake squeal phenomenon is likely to occur when the brake pad surface of the vehicle brakes relatively weakly in the process of cooling from a high temperature and in the morning.
[0014]
For this reason, regardless of whether or not the brake squeal phenomenon has occurred, the driving state and the temperature condition in which the brake squeal phenomenon is likely to occur are specified. Instead, brake squeal control was performed. Therefore, irrespective of the expression "first in the morning," the squealing control is not always the case where the brake means is operated first after the first start in the morning.
[0015]
Further, as a device for suppressing brake squeal when the vehicle is moving backward, when a start switch of the vehicle is turned on and detected by a signal of a sensor indicating that the vehicle is in reverse, the pressing force of the brake means is controlled to suppress brake squeal. The brake squeal control device may be configured. In this case, when a signal indicating that the shift lever for switching the vehicle to the reverse state is in the reverse position and a wheel speed signal in the reverse state by the wheel speed sensor are detected, brake squeal control is performed. As the method of determining the reverse state, other known methods such as a method using a yaw rate sensor as disclosed in JP-T-11-501592 may be used in addition to the above-described method.
[0016]
Embodiment
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is an overall schematic system diagram of the brake squeal control of the embodiment, and FIG. 2 is a configuration diagram of a brake squeal control device including a one-wheel brake device. As shown, the vehicle X transmits a depression force of a brake pedal 1 to a brake cylinder 5 and operates a brake hydraulic circuit (described later) of a brake means such as a disc brake (not shown) for operating a brake by the brake cylinder 5. And a control circuit 20 for sending control signals to the solenoid valves 3a and 3b provided in the hydraulic circuit. Signals from various sensors for brake squeal control are sent to the control circuit 20. . The various sensors include a sensor group related to the running state of the vehicle and a sensor group related to the temperature such as the engine E / G water temperature.
[0017]
The brake hydraulic circuit is a means as an example of specific control for reducing generation of squeal. As shown in FIG. 2, the brake pressure of the brake pedal 1 is amplified by the master cylinder 2 and the hydraulic pressure is increased by a solenoid valve of a hold valve. The brake is sent to the brake cylinder 5 via 3a to produce a braking effect. The hold valve solenoid valve 3a is a normally-open two-position switching valve, and the decay valve solenoid valve 3b is a normally-closed solenoid valve. The solenoid valve 3b is controlled to open and close by a signal output from the control circuit 20 described above. The solenoid valves 3a and 3b are provided for all four wheels, but only one for one wheel is shown for simplification. 4 is a hydraulic pump and 6 is a reservoir.
[0018]
In this brake hydraulic circuit, when the brake pedal 1 is depressed, the hydraulic pressure generated in the master cylinder 2 is sent to the brake cylinder 5 via the solenoid valve 3a in an open state, and the brake is operated. During the braking operation, the solenoid valve 3b is in a closed state. When the brake pedal 1 is released, the liquid in the brake cylinder 5 is returned to the master cylinder 2 via the solenoid valve 3a, and the brake is released. When performing such a basic operation of the brake, the illustrated brake hydraulic circuit is configured to perform ABS (antilock) control. The ABS control program is built in the control circuit 20, but the ABS control program itself is publicly known and will be briefly described here.
[0019]
That is, the ABS control calculates the wheel speed based on the input signals from the wheel speed sensors 12a to 12d, and estimates the vehicle speed from the wheel speed by referring to the value of the deceleration by a G sensor (not shown). The solenoid valve 3b is opened (the solenoid valve 3a is closed) to release the lock of the wheel for a short time based on the value of the estimated vehicle body speed, and the solenoid valve 3b is pressed again to apply braking for the wheel. The closing operation is repeated, whereby the reduction in the coefficient of friction is recovered as much as possible, and effective control is performed. The brake fluid discharged from the brake cylinder 5 by opening the solenoid valve 3b is returned to the reservoir 6, and is sucked by the hydraulic pump 4 when pressurized as necessary, and is sent out from the master cylinder 2 to the hydraulic circuit.
[0020]
In contrast to the above-described brake device, the brake squeal control device is configured using a tread force sensor 11, wheel speed sensors 12 (12a to 12d), solenoid valves 3a and 3b, and the like. That is, detection signals from various temperature sensors in addition to the above-mentioned sensors are sent to the control circuit 20, and the control circuit 20 controls the operation of the solenoid valves 3a and 3b based on the detection signals from these sensors to control brake squeal. It is configured to be. The squeal control program will be described later.
[0021]
A treading force sensor 11, wheel speed sensors 12a to 12d are provided as a sensor group relating to the running state, and an engine E / G cooling water temperature sensor 15, a vehicle compartment temperature sensor 13, and an outside air temperature sensor 14 are provided as a sensor group relating to temperature. . These sensors are sensors for detecting a condition at the time of cold and one in the morning when brake squeal is likely to occur, and assume that the measurement can be performed at the same time when the start switch 10 of the vehicle X is turned on. The running time is also measured, and the time is measured by a program or a counter in the control circuit 20 based on a signal from a reference clock 21 for generating a reference timing signal in the control circuit 20. I do. It is also assumed that the number of brakes is obtained by calculation based on a rising signal from the pedaling force sensor, and the travel distance is calculated based on signals from the wheel speed sensors 12 (12a to 12d).
[0022]
In the brake squeal control device of the embodiment configured as described above, squeal control is performed as follows. As described above, in this embodiment, the condition of the vehicle when it is cold and in the morning is first detected by various sensor signals and clock signals. In cold weather and in the morning, when the brake pad surface of the vehicle is relatively weakly braked during the cooling process from high temperature and in the morning, the brake squeal phenomenon is likely to occur. It is assumed that the water temperature of the water, the vehicle interior temperature, and the outside air temperature are each equal to or less than a certain value, and the number of brakes, the travel time, the travel distance, the total brake time, and the total brake distance satisfy the following conditions.
[0023]
When a state that satisfies the above conditions in the cold state and in the morning is detected, the solenoid valve 3b on the discharge side is opened through the solenoid valves 3a and 3b to reduce the brake pressure even during the brake operation. Controls brake squeal. In this case, the opening degree of the discharge side solenoid valve 3b is not completely opened, but may be opened for a short time (for example, only several seconds) so that the squeal disappears, and then closed again for the brake operation. .
[0024]
The above-described brake squeal control will be specifically described with reference to FIG. First, the ignition switch is start switch of the vehicle (IG abbreviated) confirms whether the ON (ON) in step S _1, to check the running state of the vehicle at S ₂ to S _6. Or the S ₂ first brake number N is 5 or less, or in the _{S 3} travel time _{T R} is less than 5 minutes, or the travel distance in _{S 4 L R} is 5km or less, _{S 5} in total braking time T _B is either 20 seconds or less, or the total braking distance in _{S 6 L B} is 50m or less, respectively determined for.
[0025]
As described above, when the signal indicating that the brake pedal 1 is depressed is sent from the pedaling force sensor 11, the number of times of braking N is counted by the counter each time, and the number of times of braking is integrated. Travel time T _R is the signal representing the running of the wheel speed sensor 12a~12d starts sent to the control circuit 20 measures the time to start the counting of the timer time based on the reference clock signal from that time. For the travel distance L _R also measures the distance corresponding to the travel time T _R by integrating the driving signal. The total braking time T _B, of the travel time T _R, measured by dividing the timing signal the beginning and end of the brake is operating, the total brake distance L _B from the traveling distance corresponding to the measured time obtain.
[0026]
_Next, to detect the temperature conditions at S 7 to S _9. In S _7, or the water temperature _{t E} of the cooling water of the engine E / G is 40 ° C. or less, or the temperature _{t R} of the vehicle in _{S 8} chamber is 15 ℃ below ambient temperature _{t out} in _{S 9} is 15 ℃ Each of the following is determined. The cooling water temperature is measured based on a signal from a temperature sensor 15 provided near the engine inlet of a cooling water pipe provided in the engine E / G. It goes without saying that the temperature sensors of the vehicle interior and the outside air are described. If it is detected each more travel state and temperature conditions is less than the set value described above, performs brake noise control by opening and closing pressure reducing electromagnetic valve 3b in S _10. Therefore, the squeal control is performed if the squeal suppression condition is satisfied, regardless of whether or not brake squeal actually occurs.
[0027]
In the illustrated example, the brake device is an example of a hydraulic pressure recovery system using a hydraulic pump and a reservoir.However, the brake device may be a hydraulic pressure recovery system using a combination of a hydraulic pump and an accumulator. Alternatively, a method of controlling brake squeal by increasing the brake fluid pressure may be adopted.
[0028]
Further, in the brake squeal control, the squeal control may be performed by applying an inverse piezoelectric effect using a piezoelectric element disclosed in Japanese Patent Application Laid-Open No. 4-54325 instead of the specific control as described above. Again, the conditions of brake noise measures whether a predetermined brake noise condition is fulfilled by the detection circuit of FIG. 3, so as to cancel the squeal exerts a reverse piezoelectric effect of a piezoelectric element as a specific control in S ₁₀ Control will be performed. This brake squeal control can also be applied to an electric brake type brake means that does not use a brake hydraulic circuit.
[0029]
FIG. 4 shows a configuration diagram of the brake squeal control device of the second embodiment. This embodiment shows an overall schematic system diagram of a brake squeal control device during reverse travel. This control device sends the wheel speed signals of the wheel speed sensors 12a to 12d and the lever position signal from the transmission shift lever 16 to the control circuit 20 in order to detect the state when the vehicle is moving backward, and detects the state when the vehicle is moving backward. Then, control is performed to increase or decrease the brake pressure via the solenoid valves 3a and 3b.
[0030]
When the vehicle is traveling backward, the ignition switch 10 (IG), which is a start switch of the vehicle, is checked to see if the ignition switch 10 is turned on, and then a signal indicating that the lever position signal of the shift lever 16 is in a reverse state and a wheel speed sensor are provided. When the control circuit 20 detects the wheel speed signals 12a to 12d, it is detected that the vehicle is in the reverse state. Also in this case, regardless of the presence or absence of brake squeal, brake squeal control is performed via the solenoid valves 3a and 3b. This brake squeal control is performed in the same manner as in the first embodiment. When the reverse state is detected using the signal of the wheel speed sensor, it is preferable to use an active wheel speed sensor capable of detecting the rotation direction of the wheel.
[0031]
【The invention's effect】
As described above in detail, the brake squeal control device of the present invention detects the predetermined cold state and the first morning state by the sensor indicating the running state and the sensor indicating the temperature state, and controls the braking force by controlling the pressing force of the braking means. The brake noise is suppressed by changing the brake noise, so the brake noise is not controlled simply by detecting the vibration or the vehicle speed below a predetermined value, but the brake noise control is performed by specifying the condition where the brake noise is most likely to occur. By doing so, there is obtained an advantage that brake squeal can be surely suppressed.
[Brief description of the drawings]
FIG. 1 is a diagram showing a schematic configuration of a vehicle brake squeal control device according to an embodiment; FIG. 2 is a schematic configuration diagram of a brake device to be installed with the same control device; FIG. 3 is a flowchart of brake squeal control; The figure which shows the schematic structure of the brake squeal control device at the time of reverse
Reference Signs List 1 brake pedal 2 master cylinder 3a, 3b solenoid valve 5 brake cylinder 10 start switch 11 pedaling force sensor 12 (12a to 12d) wheel speed sensor 13 vehicle room temperature sensor 14 outside air temperature sensor 15 cooling water temperature sensor 20 control circuit 21 reference clock

Claims (7)

When the time, running state, and temperature conditions are within predetermined ranges since the start switch of the vehicle is turned on and detected by a signal of a sensor and a clock indicating a predetermined cold state and a state of the morning, braking means Brake squeal control device that controls the pressure of the brake to suppress brake squeal. 2. The brake squeal control device according to claim 1, wherein the brake squeal is suppressed by adjusting the pressing force of the brake means by control to increase or decrease the brake fluid pressure. The brake squeal according to claim 1 or 2, wherein the predetermined cold state and the first morning state are detected by measurement signals of a sensor group indicating a running state and a temperature sensor group indicating a temperature state. Control device. The sensor group representing the traveling state is a wheel speed sensor for measuring a wheel speed and a tread force sensor representing a tread force, and the sensor group representing a temperature state is a temperature sensor for an engine coolant, a vehicle compartment temperature sensor, and an outside air temperature sensor. The brake squeal control device according to claim 3, wherein: The number of brakes based on a signal from the pedaling force sensor, a travel time and a travel distance based on a signal from a wheel speed sensor, and a total brake time and a total brake distance are measured based on both signals. Item 6. A brake squeal control device according to item 4. A brake squeal control device that suppresses brake squeal by controlling a pressing force of a brake means when a signal from a sensor indicating that the vehicle is in a reverse state is detected after a start switch of the vehicle is turned on. 7. The brake squeal control device according to claim 6, wherein a wheel speed sensor capable of detecting a rotation direction of a wheel is used as the sensor for detecting the reverse state.

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