JP2004161187A - Sensing device of air mixing in hydraulic pressure brake for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To automatically judge air mixing in a short time at high precision without preparing standard curve treading force variation characteristics in advance, in a device for sensing air mixture in a hydraulic pressure brake for a vehicle judged by the treading force variation characteristics with relative to the variation of an operating volume. <P>SOLUTION: This device comprises a motor driving device 10 for operating and driving a brake pedal 5; a load sensor 12 sensing a leg-power and a displacement volume sensor 13 sensing an operating volume; a data creation means 21 for creating variation characteristic data of a leg power against an operating volume in relative to a first operating action, and a second operating action after the operation is returned to an operating volume capable of compressing the air after the first operating action, with sensing signals of the sensors used as inputs. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a vehicle hydraulic pressure in which the detection of air entry exceeding a predetermined amount into a brake pipe from a master cylinder, which controls a hydraulic pressure by a brake pedal to a wheel cylinder, is determined based on a pedaling force change characteristic with respect to a change in the pedaling amount. The present invention relates to a brake air entering detection device.
[0002]
[Prior art]
According to Patent Literature 1, when the spring characteristic due to the inflation of air is added to the original spring characteristic of the brake system, the brake pedal is driven by stepping on the change rate of the spring constant of the brake system when the brake pedal is depressed. Actuator, a load sensor attached to the actuator for detecting the treading force, a displacement sensor for detecting the amount of treading, and characteristic curve data of the treading force with respect to the amount of treading using the detection signals of the load sensor and the displacement sensor as inputs. And a data generating means for generating the air pressure exceeding the predetermined amount by judging whether or not the rate of change in the rate of change of the pedaling force with respect to the change in the stepping amount is lower than the standard rate of change by a predetermined amount. A pneumatic detection device for a hydraulic brake for a vehicle, which includes a determination means for determining, is disclosed.
[0003]
Accordingly, when air bubbles are present, the spring characteristics are added in series to the original spring characteristics, and the spring constant of the brake system spring is delayed from being substantially constant during the compression process. By judging whether or not the change speed is lower than the standard change speed by a predetermined amount, the predetermined amount of air mixed into the brake system can be automatically detected.
[0004]
[Patent Document 1]
JP-A-2002-145042
[Problems to be solved by the invention]
However, this air intrusion detection device is based on the premise that a common standard tread force change characteristic is prepared for each vehicle type and is compared with the measurement data of the inspection vehicle. Not considered. Furthermore, this device needs to store a standard curve-shaped pedal force change characteristic for each vehicle type.
[0006]
In view of the above, the present invention has been described at the beginning of the specification, which can automatically judge air mixing in a short time and with high accuracy without preparing in advance a standard curved pedal force change characteristic for each common vehicle type. It is an object of the present invention to provide a pneumatic detection device for a vehicle hydraulic brake.
[0007]
[Means for Solving the Problems]
In order to achieve this object, according to the present invention, the detection of air entry exceeding a predetermined amount in a brake pipe from a master cylinder to a wheel cylinder, which is controlled by a brake pedal, is determined by a stepping amount. In a pneumatic detection device for a hydraulic brake for a vehicle, which is determined based on a pedaling force change characteristic with respect to a change in pedaling, an actuator for stepping on a brake pedal, a load sensor attached to the actuator to detect a pedaling force, and a stepping amount are detected The first stepping operation with the displacement amount sensor and the detection signals of the load sensor and the displacement amount sensor as inputs, and the second stepping down after returning the stepping to an intermediate amount that can compress the air after the first stepping operation. Data creating means for creating change characteristic data of treading force with respect to the amount of treading for each movement; Judging means for judging air inflow based on whether or not a difference in pedaling force for the second time with respect to the first time exceeds a predetermined amount in a braking effective area in which a braking action actually occurs based on the first and second change characteristic data; Output means for outputting the determination result.
[0008]
FIG. 3 shows a typical change characteristic of the pedaling force with respect to the amount of depression in a continuous curve shape. The variation characteristic A1 is the first variation characteristic without air entry, and passes through an initial region with play of depression of the brake pedal. The play is eliminated near the inflection point a, the brake cylinder starts to operate, and the depression near the inflection point b passes through the cylinder operation initial region involving the process of compressing the original elastic element of the brake system. From the amount, the brake pad comes into contact with the disc and enters a braking effective area where an effective braking action actually starts to occur. The change characteristic A2 indicates the amount of depression (stroke) at which the air bubble is significantly compressed after the depression, that is, the characteristic of the second time of returning to the region immediately before the inflection point b and depressing again. B1 and B2 are the first and second change characteristics when air is mixed.
[0009]
As shown in FIG. 4, when the piston 3a of the master cylinder 3 is depressed by the brake pedal in the normal state (A in FIG. 4), oil is supplied to the brake cylinder 9 (B in FIG. 4) to bring the brake into an operating state. Become. In general, when the brake pedal is returned after the first step, the oil to be filled from the reservoir tank 1 remains in the brake cylinder 9. It enters the braking effective area with a small amount of depression. Therefore, as is apparent from the change characteristics A1 and A2, the change characteristic A2 enters the braking effective area with a relatively small stepping amount with respect to the predetermined stepping amount, the pedaling force increases, and the oil pressure returns to the atmospheric pressure. The pressure is re-pressurized before turning off, and the amount of oil increases without the brake cylinder 9 returning, so that the pressure rises with a relatively small stroke and the inclination becomes steep. On the other hand, the change characteristic B1 is delayed from entering the effective braking region by the stroke required for the compression of the bubble, and the amount of depression increases. In addition, the inclination becomes slightly gentle to further compress the bubbles depending on the amount of air. Further, the change characteristic B2 almost does not include the process of compressing bubbles near the inflection point b which enters the braking effective area without air, so that the change characteristic B2 almost coincides with the change characteristic A2 or is slightly gentle depending on the amount of air. become. Therefore, the difference between the change characteristic B2 and the change characteristic B2 when the bubble is included is larger than the difference between the change characteristic A2 and the change characteristic A1 when the bubble is not included.
[0010]
According to this principle, the data creating means creates sampling plot data or continuous curve-like change characteristic data by using the detection signals of the load sensor and the displacement sensor as input, and the judgment means makes the first change characteristic data A1, B1. Based on the change characteristic data A2 and B2 for the second time, it is determined whether or not the air pressure has entered based on whether or not the difference in the pedaling force for the second time with respect to the first time in the braking effective area exceeds a predetermined amount. Further, there is a difference in inclination between the first change characteristic data A1 and B1 and the second change characteristic data A2 and B2 due to the final compression action of the already compressed bubbles. Therefore, it is possible to judge whether or not to enter the air, independently or in consideration of the difference in the pedaling force, depending on whether or not the difference in the inclination exceeds a predetermined amount.
[0011]
The return of the depressed amount halfway is not limited to the area immediately before the inflection point b where the air can be significantly compressed, but can be reduced to about half the air in some cases in consideration of the detection accuracy. It can also be set near the inflection point b. If the second step is delayed or forced to return so that the oil does not remain in the brake cylinder 9 after the first step, the change characteristic A2 approaches the change characteristic A1, and therefore the air bubbles of the air bubbles are reduced. The change characteristic B2 whose influence is avoided approaches the change characteristic A1. Also in this case, similarly, a difference is generated with respect to the change characteristic B1 including the air compression process, and air entry is detected based on the same principle.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
A pneumatic detection device for a vehicle hydraulic brake according to an embodiment of the present invention will be described with reference to FIGS. 1 and 2. In the vehicle hydraulic brake, as is well known, the brake fluid stored in the reservoir tank 1 is increased by a booster 4 that amplifies the pedaling force by the intake pressure of the engine in the master cylinder 3 in response to the depression of a brake pedal 5. The brake system is configured to be pressurized and supplied to the wheel cylinder 6 via the brake hose 8.
[0013]
The pneumatic detection device depresses the brake pedal 5 in order to detect air that exceeds a predetermined amount and mixes with the liquid in the brake pipe that reaches the wheel cylinder 6 via the master cylinder 3 with the reservoir tank 1. A motor drive device 10 with a gear mechanism as an actuator to perform, a load sensor 12 provided at the tip of the drive rod 11 for detecting a tread force, and a displacement sensor for detecting a rotation amount of the motor for detecting a tread amount. It comprises a displacement amount sensor 13 of the drive rod 11 used and a signal processing device 20 which receives these detection signals.
[0014]
The motor drive device 10 is supported by a base 15 that inclines the drive rod 11 so that the drive rod 11 can contact the tread surface of the brake pedal 5, and a predetermined maximum pedaling force of the drive rod 11 is detected in response to a start signal. Until it is turned back on, and then immediately retracts until a preset standard predetermined stepping stroke is detected that can fold back and significantly compress the bubbles, and then advance again until the maximum pedaling force is detected, A control circuit for returning to the original position is attached. In addition, the motor driving device 10 rotates at a constant speed via the reduction gear irrespective of the load on the premise that the booster 4 is not operated. Therefore, the booster 4 has a large output with respect to the output required for the stepping drive when the booster 4 operates.
[0015]
The signal processing device 20 is configured using a personal computer in which a program for judging air entry is installed. The signal processing device 20 A / D converts the detection signals of the load sensor 12 and the displacement amount sensor 13 by an interface unit and captures the signals. The change characteristics of the pedaling force F with respect to the pedaling amount x for the second pedaling operation after the first pedaling operation and the second pedaling operation after returning the pedaling amount to the pedaling amount that can greatly compress the air immediately after the first pedaling operation. Data creation means 21 for creating certain characteristic curve data, standard data storage means 22 for storing standard data of the second pedaling force difference with respect to the first time, and first and second characteristic curves created by data creation means 21 Judgment of air entry exceeding a predetermined amount is determined based on whether or not the difference in the second pedaling force with respect to the first operation in the braking effective area exceeds the predetermined amount. Determining means 23, an output means 24 for notifying the judgment data and the pass / fail result on the screen display 24a, and further notifying light or sound, for example, an abnormal amount of air by a warning lamp 24b, and sequentially storing the judgment results in the memory. Data recording means 25 for recording. A start signal is supplied to the motor drive device 10 via an interface unit in response to operation of the keyboard 26.
[0016]
The data creating means 21 sequentially acquires detection signals of the load sensor 12 and the displacement sensor 13 and creates plot data of first and second change characteristics of the pedaling force with respect to the stepping amount, and plot data creating means 21a. And a curve data creating means 21b for converting the data into first and second continuous characteristic curve data by approximation processing. The approximation process is performed by calculating, for example, a sixth-order approximation curve by regression analysis based on plot data of, for example, about 40 points for all strokes of the depression.
[0017]
The determination means 23 determines the standard depression range starting point for the first and second characteristic curve data C1 and C2 (see FIG. 2A) obtained by approximating the measured xF change characteristic data. slope data creating means 23a for extracting characteristic curve data C1 and C2 between x1 and the amount of step end x2, and creating first and second slope data D1 and D2 (see FIG. 2B) of a linear function by approximation processing. And the first tilt data D1 is subtracted from the second tilt data D2 to create differential tilt data D3 (see FIG. 2C) that satisfies the linear function y = ax + b, and a constant b (pedal force difference ΔF) Is provided with function data creating means 23b for determining whether or not exceeds a predetermined amount ΔFs and whether or not the proportionality constant a (difference gradient θ3) exceeds a predetermined amount. 2B and 2C are enlarged.
[0018]
In FIG. 2A, the two-dot chain line shows the first characteristic curve data with almost no air entry for reference. The determining means 23 determines that the difference inclination θ3 (θ2−θ1) is not less than the predetermined amount due to the fact that the inclination θ1 becomes gentle due to slight compression of the compressed air bubbles in the effective braking region, as well as the pedaling force difference ΔF. It is also determined whether or not the inclination exceeds θs. The standard data storage means 22 stores, for each vehicle type, a predetermined value serving as a criterion for determining ΔFs and θ3.
[0019]
Note that x1 is preset in the vicinity of the effective braking area without air, and x2 is preset in the vicinity of the second maximum depression amount. These x1 and x2 can also be set by the structural stroke of the master cylinder. . Further, the second return amount can be set by analyzing a change in the sampling data so that the air compression process can be used more effectively. Further, as the determination means, for example, the determination can be made based only on the pedaling force difference ΔF with respect to a predetermined stepping amount in the middle of the braking effective area between x1 and x2. In this case, the determination can be made based on the sampling data itself without performing the approximation curve processing, and in that case, the apparatus configuration may be simplified without driving at a constant speed.
[0020]
The operation of the air entering detection device thus configured is as follows. During the manufacturing process in which the engine is not yet mounted, the load sensor 12 mounted on the tip of the drive rod 11 is brought into contact with the brake pedal 5 of the vehicle carried in the inspection process while the booster 4 is not operated. Then, the motor drive device 10 is operated to move the brake pedal 5 at a constant speed.
[0021]
Thereby, the data creating means 21 samples the digitized detection signals of the load sensor 12 and the displacement sensor 13 at the time of the first forward movement and at the time of the second forward movement from the middle, and further performs continuous processing by approximation processing. First and second curved characteristic curve data C1 and C2 are created. The determination means 23 creates difference inclination data D3 of the function y = ax + b for the characteristic curve data, and determines whether or not the pedaling force difference ΔF exceeds a predetermined amount of pedaling force difference ΔFs. At this time, if the subtraction value of ΔF from ΔFs is small, it is determined whether or not the difference inclination θ3 exceeds a predetermined amount of inclination θs, that is, whether or not ΔF tends to increase with respect to a larger pedal effort. Pass / fail is determined by In the sensory test, it has been confirmed that the amount of air that can be detected is about 0.5 cc, but can be detected with high accuracy up to about 0.2 cc.
[0022]
As a result of the determination, the numerical values of the pedaling force difference ΔF and the difference inclination θ3 are displayed on the screen display 24a together with the characteristic curve data C1, C2, etc., and the data on each vehicle is sequentially stored. As shown in the figure, when the pedaling force difference ΔF exceeds a predetermined pedaling force difference ΔFs, it is also notified by the alarm lamp 24b.
[0023]
The pneumatic detection device according to the present invention stores the data of the predetermined pedaling force difference ΔFs and the predetermined difference inclination θs, which are the criteria for determination, as values specific to the vehicle type, or as values themselves or coefficient values for the reference vehicle type. Thus, high-precision pneumatic detection can be performed without preparing the standard characteristic curve data for each vehicle type, eliminating the influence of variations in the brake characteristics of the vehicles for various vehicle types individually.
[0024]
FIG. 5 shows an actuator according to another embodiment, in which a timer 36 measures the detection signals of an air cylinder 30 for driving the brake pedal 5 with a driving rod 31 and a displacement sensor 33 using the linear encoder. A speed calculating means 35 for calculating the speed of the drive rod 31 by using a pressure regulator 38 for controlling the pressure of the compressed air supplied to the air cylinder 30, and a response to the deviation of the actual speed signal from the standard constant speed signal. And control means 37 for controlling the pressure regulator 38. Thus, when the booster 4 is not operated, the air cylinder 30 drives the brake pedal 5 at a constant speed by controlling the pressure of the compressed air. Instead of the air cylinder 30, a hydraulic cylinder may be used in the same manner. It is to be noted that an air cylinder can naturally be used even when driving at a constant speed.
[0025]
【The invention's effect】
According to the first aspect of the present invention, it is possible to determine the deviation of the characteristic data between the first time and the second time for each vehicle without preparing the standard curve-shaped change characteristic data of the pedaling force with respect to the amount of depression. High-accuracy air entry detection is possible. It is no longer necessary to prepare standard change characteristic data specific to various types of vehicles. According to the second aspect of the present invention, the determination means simply determines whether or not the difference between the second stepping force and the first stepping force with respect to the predetermined stepping amount exceeds a predetermined amount. Detection becomes possible. According to the third aspect of the present invention, by judging whether or not the slope of the difference curve data of the second curve data with respect to the first curve data exceeds a predetermined amount, the state of the change in the pedaling force in a wide range of the effective braking area is determined. Air can be detected. According to the fourth aspect of the present invention, the detection of the air entry is determined with higher accuracy based on the determination of both the difference in the pedaling force and the degree of inclination of the increase. According to the fifth aspect of the present invention, the measurement is performed under the constant speed driving even when the booster is not operated, so that high-precision change characteristic data can be obtained based on high-precision sampling data at any stage of the manufacturing stage. In addition, even for a completed vehicle, high-precision pneumatic detection can be performed without operating the engine.
[Brief description of the drawings]
FIG. 1 is a diagram showing a configuration of a pneumatic detection device for a vehicle hydraulic brake according to an embodiment of the present invention.
FIG. 2 is a diagram illustrating a determination operation of the device.
FIG. 3 is a diagram illustrating the operation principle of the device.
FIG. 4 is a diagram illustrating the operation principle of a brake system to be detected by the device.
FIG. 5 is a diagram showing a configuration of an actuator according to another embodiment of the device.
[Explanation of symbols]
3 Master cylinder 5 Brake pedal 6 Wheel cylinder 10 Motor drive 9 Brake cylinder 12 Load sensor 13, 33 Displacement sensor 30 Air cylinder

Claims (5)

The hydraulic pressure is controlled by the brake pedal. The detection of air inflow into the brake pipe from the master cylinder to the wheel cylinder exceeding a predetermined amount is detected based on the pedal force change characteristics with respect to the change in the amount of depression. In the entry detection device,
An actuator for depressing and driving a brake pedal, a load sensor attached to the actuator for detecting a pedaling force, a displacement sensor for detecting a stepping amount, and a first time input of detection signals from the load sensor and the displacement sensor, Data for creating change characteristic data of the pedaling force with respect to the stepping amount for the stepping operation and for the second stepping operation after the stepping is returned to the stepping amount in the middle of compressing the air after the first stepping operation. The air-inflow is determined based on the creation means and whether or not the difference between the first pedaling force and the second pedaling force exceeds a predetermined amount in a braking effective area where a braking action actually occurs based on the first and second change characteristic data. And an output means for outputting the result of the determination. It enters the sensing device. 2. The air for a hydraulic brake for a vehicle according to claim 1, wherein the judging means judges whether or not a difference between a second pedaling force and a first pedaling force with respect to a predetermined pedaling amount in the braking effective area exceeds a predetermined amount. Ingress detection device. Data creation means for sequentially taking in the detection signals of the load sensor and the displacement sensor and creating first and second plot data of the change characteristic of the treading force with respect to the treading amount; and plotting the plot data by approximation processing. Curve data creating means for converting into first and second continuous curve data;
The determination means includes difference curve data creation means for creating difference curve data of the curve data for the second time with respect to the first time in the braking effective area, and determines whether or not the slope of the difference curve data exceeds a predetermined amount. The air-filled detection device for a vehicle hydraulic brake according to claim 1, wherein: In addition to determining whether or not the inclination exceeds a predetermined amount, the determination means may determine whether or not the second stepping force difference from the first stepping force exceeds the predetermined amount with respect to the stepping amount serving as the starting point of the difference curve data. The air pressure detection device for a vehicle hydraulic brake according to claim 3, wherein the determination is made. The pneumatic detection device for a hydraulic brake for a vehicle according to any one of claims 1 to 4, wherein the actuator has an output capable of being stepped on at a constant speed while the booster is not operating.

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