JP2000289593A - Brake assisting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow a brake including a ABS to maximize its performance without operating errors by avoiding abnormal situations such as fading phenomenon working on a brake device, and producing appropriate braking that match the personality of each driver. SOLUTION: This device includes an α-computing means 46 whereby the rule property of stamping force information from a stamping force detecting sensor 10 embedded in place in a hole provided in the arm part of a brake pedal and frictional force information form a frictional force detecting sensor 7 arranged in the mounting part of a brake device is computed according to the stamping force information and the frictional information, a P-computing means 47 for determining the target value of a source of auxiliary operating fluid pressure for replenishment when a braking limit is reached, and a solenoid valve control means 48 for generating appropriate braking forces by controlling each kind of valve system according to its necessity.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a method for monitoring whether or not a braking force corresponding to a pedal operation by a driver of a vehicle is properly transmitted to a brake device, and for not transmitting the brake force correctly or fading. When the brake braking limit due to the phenomenon is determined, by increasing and assisting to recover the braking force,
ABS (antilock break system)
The present invention relates to a brake assist device for contributing to maximizing the braking performance including m).

[0002]

2. Description of the Related Art As a brake device for decelerating and stopping an automobile, conventionally, a hydraulic pressure is generated in a master cylinder by operating a brake pedal, and the hydraulic pressure is applied to a wheel cylinder provided for each wheel. A hydraulic brake device has been used in which a friction member formed of a brake shoe is transmitted to and pressed against a rotating body such as a brake disk by the operation of the wheel cylinder.

[0003] In recent years, however, brake control represented by ABS, that is, control for electrically measuring various quantities acting on wheels and realizing ideal wheel behavior based on the detection results, has become widespread. On the other hand, there is a current situation that these functions are not sufficiently exhibited. Specifically, ABS
Generates an ideal braking force based on the output from a wheel speed sensor composed of gears that rotate with the wheels during emergency braking and under conditions where a brake fluid pressure exceeding a certain value is generated. Although the brake fluid pressure is electromagnetically controlled as described above, during emergency braking, a driver such as a woman or an elderly person who has a weak or unfamiliar or is in a panic condition has a strong brake operation speed but a strong brake pedal. Can't step and therefore AB
There is a case where S does not function sufficiently and can generate only a small braking force. Further, even in the latter half of the brake control, such a driver cannot continue to depress the brake pedal for a long time, and the braking force is reduced, so that appropriate brake control cannot be maintained. As a result, they can be a cause of serious accidents, in other words, a result that is contrary to the driver's intention to brake, depending on the driver's ability. there were.

[0004] In view of such problems, the applicant of the present application has previously proposed a driver who intends to return to a normal brake operation state by shifting to emergency braking for the purpose of avoiding an accident or to ensure safety. An electrically controlled brake assist device that directly reflects the intention to operate the pedal to the control side is provided.
(See Japanese Patent Application No. 10-343,531)

[0005] This electrically controlled brake assist device is
(A) a brake pedal mounted on a vehicle, (b) a tread force detection sensor that directly measures a brake tread force, and (c)
It is configured to include a wheel rotation suppressing means including an ABS for suppressing the rotation of the wheel, and (d) a control means for controlling the wheel rotation suppressing means based on a detection result from the treading force detection sensor. the depression speed parameter V _F is the slope of the pedal force information F and its trajectory obtained from the sensor, as well as determining the will of the emergency stop of the driver, in a situation that does not depresses the strong brake pedal,
The control method is switched to a means for electrically generating a braking force.

However, in the above-described electrically controlled brake assist device, it is determined whether or not the brake braking force generated by the driver's operation of the pedal is sufficiently transmitted to the brake device that actually suppresses the rotation of the wheels. Due to the unclearness, a problem may occur depending on the running state of the vehicle. For example, when a brake operation is continuously performed on a steep slope, the braking force transmitted to the brake device tends to decrease and the braking limit is reached even though the brake pedal is depressed. There are situations where this occurs. This is because the frictional heat generated by the contact between the brakes, which are the friction members, and the brake discs, which are the rotating bodies, lowers the friction coefficient between the brakes and the brake discs, or the frictional heat is transmitted to the brake fluid and the viscosity of the brake fluid is increased. This is because a decrease in pressure causes a pressure decrease. Such a phenomenon is generally called a fade phenomenon.

That is, the above-mentioned situation leads to a fatal accident that puts not only the occupants of the vehicle but also the people around them into danger, and the brake plays an important role of protecting human lives. The safety of the device was not sufficient.

Further, as a pedaling force detection sensor used in a general vehicle, there is provided a strain sensor which is directly mounted on a tread surface of a brake pedal or a surface thereof and measures a change in electric resistance caused by a pressure acting on the tread surface when the pedal is operated. The mainstream is a pressure-sensitive pedal force sensor composed of a gauge.

[0009] However, the pressure acting on the tread surface of the brake pedal does not act uniformly over the entire tread surface. Therefore, there is a problem that the variation error of the detection value increases due to the accuracy of the attachment position of the treading force sensor, and since the brake pedal is directly attached to the tread surface or the surface thereof, it is extremely susceptible to disturbance factors, so that accurate It was very difficult to determine the pedaling force.

[0010]

DISCLOSURE OF THE INVENTION The present invention has been conceived in view of the above circumstances, and it is possible to quantitatively and accurately grasp the actual operation of the driver depressing the brake pedal, and to directly grasp the operation. By reflecting on the brake performance, including ABS, maximize the brake performance without malfunction, and monitor whether the brake braking force generated by the operation is transmitted to the brake device accurately. If not, monitor the brake braking force. To provide a brake assist device that further considers safety by assisting and enhancing to recover
The subject.

In order to solve the above problems, the present invention takes the following technical measures.

According to a first aspect of the present invention, a shearing force acting on an arm portion of a brake pedal by an operation force artificially or mechanically applied to a brake pedal of a vehicle is applied to a brake pedal force acting on the brake pedal. An arbitrary number of first sensors to be detected as, a rotating part that rotates with the wheel, and a non-rotating part that is brought into contact with the rotating part and suppresses rotation of the wheel, is mounted near a brake device,
An arbitrary number of second sensors for detecting a frictional force acting between the rotating part and the non-rotating part; pedaling force information corresponding to a brake pedaling force obtained from the first sensor; and the second sensor And a control means for adjusting a brake braking force acting on the vehicle based on frictional force information corresponding to the frictional force obtained from the vehicle.

The pedaling force information and the frictional force information may be obtained directly from one sensor, or may be obtained by calculating a detection signal from the sensor. For example, the friction force information can be obtained directly from one sensor, or the detection signal from a sensor that outputs information corresponding to the force with which the wheel cylinder presses the non-rotating portion of the brake is added to the brake signal. It can also be obtained by multiplying a constant according to the coefficient of friction between the rotating disk and the brake disk. Moreover,
It may be obtained by calculating detection signals from a plurality of sensors.

As the second sensor, for example, a stress detection sensor composed of a strain gauge for detecting a shear stress acting on a connection point between the brake device and the suspension main body can be used, but is not limited thereto. Further, as the frictional force detecting means, a brake circuit including a strain gauge disposed at an appropriate portion of a brake caliper support member and disclosed in Japanese Patent Application Laid-Open No. 3-273948 previously proposed by the same applicant as the frictional force detecting means is used. Detecting means configured to output a signal proportional to the frictional force between the brake disks may be substituted.

The control means controls an electromagnetic valve incorporated in, for example, a hydraulic pipe of the brake device.

The brake braking force acts according to the friction force generated by pressing a brake made of a friction member against a brake disk rotating together with the wheel, and is roughly proportional to the friction force between the wheel and the road surface. It is related to the force that tries to suppress the rotation of the wheel.

According to a preferred embodiment of the present invention, the control means obtains a ratio between the pedaling force information and the frictional force information based on the pedaling force information and the frictional force information, and this ratio is set in a predetermined range. When the vehicle deviates from the inside, adjustment is made to increase the brake braking force acting on the wheels.

Generally, between the pedaling force information and the frictional force information,
There is a relation that is constantly expressed by a linear function FB = α ₃ (α ₁ F + α ₂ ). Here, FB is the friction force between the brake shoe and the brake disc, F is the brake pedal force, α
₁ , α ₂ and α ₃ are constants. When the respective information is processed as digital data, the ratio can be obtained, for example, by calculating the ratio α = FB / F from the treading force information and the friction force information at predetermined time intervals.

According to another preferred embodiment, the control means determines whether or not the brake device has failed or has reached the braking limit based on the pedaling force information and the frictional force information. If so, an auxiliary brake device different from the brake device is operated to adjust the brake braking force to be increased.

As the auxiliary brake device, for example, a parking brake can be used. However, the present invention is not limited to this, and a conventional brake provided with a mechanism for pressing a brake shoe made of a conventional friction member against a brake disk rotating with wheels. It shows a device provided independently of the brake device and having the property of suppressing the rotation of wheels.

According to another preferred embodiment, there is provided a notifying means for notifying that the brake device has failed or the braking limit has been reached, and the control means has the notifying device that the braking device has failed or the braking limit has been reached. Sometimes the notification means is activated.

The notification means includes, for example, a visual display using a monitor or a lamp, and an audible display using a siren or the like for issuing an alarm, but is not limited thereto.

According to the second aspect of the present invention, the shear force acting on the arm portion of the brake pedal due to the operation force artificially or mechanically applied to the brake pedal of the vehicle is applied to the brake pedal force acting on the brake pedal. Based on an arbitrary number of first sensors which are detected as and the pedaling force information corresponding to the brake pedaling force obtained from the first sensor when the driver depresses the brake pedal, to the present maximum value of the brake pedaling force by the driver up to the present. The maximum pedal force discrimination storage means for storing the maximum value as the maximum pedal force of the driver, and acts on the wheel based on the maximum pedal force stored in the maximum pedal force discrimination storage means and a predetermined reference value. And a control means for adjusting a brake braking force to be applied.

According to a preferred embodiment of the present invention,
When the maximum pedaling force is smaller than the reference value, the control unit adjusts the brake braking force according to the difference between the maximum pedaling force and the reference value.

According to another preferred embodiment, there is provided a notifying means for notifying the driver of the maximum pedaling force.

The notification means includes, for example, a visual display using a monitor or a lamp, and an audible display using a siren or the like that issues an alarm, but is not limited thereto.

According to another preferred embodiment, the first sensor is constituted by a strain gauge and is embedded and fixed in a hole formed at a position including a stress center band existing in the brake pedal.

The central stress zone refers to a structure, for example, a brake pedal in the present invention, but it is intended to measure the internal stress when external forces are applied to the structure from a plurality of directions. This is a distribution band in which only the stress due to the external force of the directional component exists, and there is no or extremely small effect of the internal stress acting by the external force of the other directional component.

According to another preferred embodiment, the first sensor is mounted on a connecting member connecting the brake pedal and the master cylinder.

According to another preferred embodiment, the vehicle is an electric vehicle that is driven by an electric motor,
The control means adjusts the brake braking force by controlling the electric motor.

As described above, according to the present invention, the control parameter is determined by using the pedaling force information according to the brake pedaling force and the frictional force information according to the frictional force acting between the rotating part and the non-rotating part constituting the brake device. By using it, it is possible to monitor at any time whether the brake braking force based on the driver's pedal operation is properly transmitted to the brake device side, and if not, assist and increase to recover to the appropriate brake braking force Thus, accurate control can always be realized. In addition, the accuracy of control is improved because the brake pedal force is regarded as a shear stress acting uniformly inside the brake pedal.

Further, by using the ratio between the brake pedaling force and the frictional force as a control parameter, the brake can be applied not only at the time of emergency braking as in the prior art but also especially when a continuous braking operation is performed on a steep slope. A fade phenomenon in which the braking force is reduced can be dealt with beforehand, and the braking performance is maximized safely and reliably. In addition, since the tendency of the occurrence of the fade phenomenon can be predicted and determined in advance, a noticeable effect of notifying the information to a person inside or outside the vehicle and avoiding an accident can be obtained.

Further, since the maximum depression force when the brake pedal is depressed strongly is managed as personal information of the driver and the brake braking force is adjusted based on this maximum depression force, the uniform control as in the prior art is not used. Instead, control according to the driver's personality, such as various genders and ages, can be realized, and control accuracy can be particularly improved. Furthermore, by objectively evaluating the driver's accident avoidance ability based on the maximum pedal effort and notifying the driver in advance of this, the driver's awareness of the risk of accident avoidance can be raised, and in particular, the ability to depress the brake pedal It has a remarkable effect on elderly and female drivers who are assumed to be weak.

Further, in order to embed and fix the first and second sensors in holes located at positions enclosing the stress center band existing in the target structure and to grasp them as shear stress acting on the structure, a conventional method is used. The problem that the variation of the detection value increases due to the accuracy of the mounting position of the sensor as in the pressure sensing type pedal force sensor can be solved well, and the pure detection value from which other crosstalk components are eliminated is used as a control parameter. Because it can be used as a control, the accuracy of control is particularly improved.

Other features and advantages of the present invention will become more apparent from the detailed description given below with reference to the accompanying drawings.

[0036]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be specifically described below with reference to the drawings. It should be noted that what is shown here is an example of a preferred embodiment, and the scope of the claims is not limited to the examples shown here.

FIG. 1 shows a mounting example of a pedaling force detecting sensor constituting a brake operating force detecting means according to the present invention.
The pedaling force detection sensor 10 is connected to the arm 2 of the brake pedal 1.
Is embedded and fixed in the hole 5 formed in the hole.

The hole 5 is provided along the width direction of the brake pedal 1 and at a position including a stress center band existing in the brake pedal 1. Here, when considering the distribution of internal stress when an external force acts on the brake pedal 1 from a plurality of directions, only the stress due to the external force of the directional component to be measured exists. Is defined as a distribution band in which there is no or extremely small effect of internal stress acting due to external force of the directional component. That is, the brake pressing force F acting on the pedal tread surface 3 is x
A component force f1 of the axial component, a component force f2 of the z-axis component,
Although it can be regarded as a vector-like resultant force with the component force f3 of the y-axis direction component, only the shear stress acting due to the component force f1 of the x-axis direction component exists, and the component force f2 of the z-axis direction component exists. The hole 5 may be provided so as to include a place where there is no or extremely small influence of the bending stress due to the torsion or the torsional stress due to the component force f3 of the y-axis direction component, and the treading force detection sensor 10 may be embedded and fixed in the place. . The x-axis direction corresponds to the reciprocating direction of the push rod 4, the y-axis direction corresponds to the width direction of the brake pedal 1, and the z-axis direction corresponds to the vertical direction perpendicular to the moving direction of the push rod 4. Show. The component force f3 rotates around the x-axis mainly because the load point of the brake pedal force F acting on the pedal tread surface 3 does not coincide with the bonding surface between the arm portion 2 and the tread surface 3 of the brake pedal. It is a component that generates torsional stress.

As a method of setting the holes 5, for example, a FEM (f
A method using an inite element method analysis is generally used. That is, the brake depression force F
Is obtained by FEM analysis when each of the component forces f1, f2, and f3 acts alone, and a distribution diagram of bending and torsional stresses caused by the component forces f2 and f3 acting on the brake pedal 1 obtained by the FEM analysis. To determine a range where both stresses are minimum, and collate the determined range with a shear stress distribution diagram based on the component force f1 so as to include the optimum position where the shear stress is detected at the maximum. You only have to decide.

In this way, it is possible to detect the shear stress, that is, the brake pressing force F, which is extremely accurate, excluding the influence of the stress having a component in another direction other than the shear stress. Moreover, since the stress acting on the brake pedal 1 is directly measured, the measurement corresponding to only the force actually applied to the brake pedal 1 is possible, eliminating unstable elements such as friction and play of the brake pedal 1 itself. become. The hole 5 does not necessarily need to be penetrated in the width direction of the brake pedal 1, and may be, for example, a blind hole having a depth of 5 mm. The hole diameter is, for example, 7 mm.

Further, from the viewpoint of stress distribution in material mechanics,
It is known that shear stresses are evenly distributed over the structures acting on them. Therefore, the shear stress from the brake pressing force F acting on the pedal tread surface 3 is uniformly distributed throughout the brake pedal 1. That is, the detection of the brake depression force F independent of the sensor mounting position accuracy, which eliminates the disadvantages of the pressure sensing type depression force sensor employed as the conventional depression force detection sensor, is realized.

FIG. 2 is an external view of the treading force detection sensor 10 according to the present invention. The treading force detection sensor 10 is mounted in a spot on the central stress band. Further, the pedaling force detection sensor 10 includes, for example, a rectangular parallelepiped base 20 made of a metal material or a silicon-based material having the same stress transmission characteristics as a brake pedal, and four strains made of a metal resistance thin film adhered to the surface thereof. Gauges 21, 22, 31, 32
It is composed of When an external force is applied to the substrate 20 from one direction, the strain gauge uses, as an output value, a change in electric resistance due to deformation of a resistance thin film of the strain gauge in response to internal strain generated by the external force. In general, a thin film technology using a commercially available metal resistor or a semiconductor process is known, but the present invention is not limited thereto.

The strain gauges 21 and 22, and 31 and 32
Have a relationship in which the direction of action (x-axis direction) of the shear stress f1 acting on the arm portion 2 of the brake pedal on the attachment surface of the base 20 is orthogonal to each other with an inclination of 45 ° with respect to the reference line. are doing. The attachment surfaces of the base 20 to which the strain gauges are attached are perpendicular to the direction of insertion into the hole 5 (y-axis direction) and face each other.
Further, the strain gauges 21 and 31 and the strain gauges 22 and 32 are disposed so as to be respectively symmetric with respect to the center plane of the base body 20 parallel to the bonding surface.

FIG. 2 shows a structure in which the inside of the hole 5 is filled with an isolating material 13 and is integrally formed with the treading force detection sensor 10 and joined thereto. The detection sensor 10 is completely shut off from the outside world, and is not only securely bonded and fixed to the inside of the hole 5, but also functions as an insulated member that protects against a disturbance factor from an external atmosphere. A stable detection result corresponding to only the pedaling force F can be provided.

The separator 13 is made of an epoxy resin or an insert metal made of a material having the same stress transmission characteristics as the brake pedal 1. As a joining method using an insert metal, a method generally called liquid phase diffusion joining is known, which utilizes a difference in thermal expansion coefficient between joining materials by locally heating a joining surface. Is pressurized to make the insert metal inserted into the joint surface into a molten liquid phase, and then isothermally solidified using the diffusion. As insert metal,
Amorphous N with low melting point and relatively easy isothermal solidification
i or a Ni alloy containing boron having an effect of lowering the melting point and having a large diffusion coefficient is used.

By constructing such an arrangement relationship between the acting direction of the shear stress and the strain gauge, it is possible to more effectively detect only the shear stress corresponding to the brake depression force F. The theoretical basis will be described below with reference to FIG.

When a certain one-directional stress is applied to the substrate 20, the resistance change amounts of the strain gauges 21, 22, 31, 32 are equivalent in absolute value. This relationship is established regardless of whether the stress direction is shearing, bending, or twisting, and only the polarity changes according to the direction of each stress. Specifically, when stress acts in the shear direction, FIG.
As shown in (a), strain gauges 21 and 31 undergo deformation in the tensile direction, and strain gauges 22 and 32 undergo deformation in the compression direction. Now, assuming that the absolute value of the resistance change due to the deformation of each gauge is ε, the strain gauges 21 and 31 undergo deformation in the tensile direction, and therefore + ε is applied to the strain gauges 22 and 32 due to the deformation in the compression direction. ε is output. Next, considering the output value from each gauge when a bending stress is applied, the strain gauges 21 and 22 are subjected to a deformation in the tensile direction, so that + ε is applied. And outputs -ε (see FIG. 3B).
Similarly, in the case of torsional stress, the strain gauges 21 and 32 output + ε, and the strain gauges 22 and 31 output −ε, respectively (see FIG. 3C). Here, the output values obtained from the respective strain gauges are substituted into Equation 1 below. In the following formula, a is the output value of the strain gauge 21, and b is the strain gauge 22.
, C is the output value of the strain gauge 31, d is the strain gauge 3
2 respectively. E is a logic operation value corresponding to the stress, and Expression 1 is realized by an operation circuit included in the first sensor. The arithmetic circuit may be realized by using strain gauges 21, 22, 31, 32 in combination with a bridge circuit, which is a well-known technique, or by using an output signal obtained from each strain gauge as a C signal.
It is also possible to adopt a configuration in which the equation 1 is calculated by taking in the PU.

[0048]

E = (a + c) − (b + d)

When the above equation (1) is calculated based on the output tendency of each strain gauge according to the stress acting on the substrate 20, the logic operation value E due to the shear stress is 4ε.
The logic operation value E due to other stress becomes zero in any case. That is, by arranging the strain gauges in such a manner that the strain gauges are orthogonal to each other at an angle of 45 ° with respect to the direction of action of the shear stress f1 acting on the arm portion 2 of the brake pedal, the The effect of eliminating the influence and detecting only the shear stress can be more remarkably obtained.

The pedaling force detecting sensor according to the present invention can be realized by substituting a pressure sensing type stress sensor (load cell) mounted on the push rod 4 connecting the master cylinder and the brake pedal 1. However, this is not the case.

FIG. 4 shows a mounting example of the frictional force detecting sensor according to the present invention.
Caliper housing 11 that holds brake shoe 9 made of a friction member that sandwiches and presses brake disk 8
The suspension body is mounted in a hole 15 provided in a caliper support member 12 to which the suspension body is connected and fixed.

The hole 15 is provided in parallel with the longitudinal direction of the axle integrated with the suspension and at a position including the center of stress existing in the suspension. Here, the stress center zone means that only the shear stress caused by the frictional force acting between the brake shoe 9 and the brake disc 8 exists, and there is no influence of the internal stress applied by the external force of other directional components. Alternatively, the distribution band is extremely small.

Normally, in addition to the frictional force acting between the brake shoe 9 and the brake disc 8, the suspension body has a road surface frictional force acting between the road surface along the traveling direction of the vehicle and the tire blocks, and a vehicle weight. And the normal drag by
The lateral force acting in the vehicle width direction acts simultaneously as a vector resultant force. The frictional force acting between the brake shoe 9 and the brake disc 8 is hereinafter referred to as a braking force to distinguish it from the road surface frictional force.

That is, the hole 15 is provided so as to include a place where only the shear stress acting due to the braking force is present and the internal stress due to the road surface frictional force, the normal force, and the lateral force is not or extremely small. The frictional force detection sensor 7 may be embedded and fixed at the position of the stress center band. The specific setting method of the hole 15 is as described above, and thus will not be described here.

FIG. 5 is an external view of a friction force detection sensor according to the present invention. The friction force detection sensor 7 has a rectangular parallelepiped shape made of, for example, a metal material or a silicon-based material having a stress transmission characteristic close to that of a suspension. Base 3
0, and four strain gauges 17, 18, 27, 28 made of a metal resistive thin film adhered to the surface.
As a strain gauge, a gauge using a thin film technology based on a commercially available metal resistor or a semiconductor process is generally known, but is not limited thereto.

The strain gauges 17 and 27 are parallel to the reference line 23 connecting the center points of the bolt holes 19 connecting the caliper housing 11 and the caliper support member 12 on the attachment surface of the base 30. It is arranged in. Further, the strain gauges 18 and 28 are disposed so as to be orthogonal to the strain gauges 17 and 27 forming a pair. Further, the substrate 3 to which each strain gauge is attached
0 is perpendicular to the direction of insertion into the hole 15 and faces each other, and the strain gauges 17 and 27 and 18 and 28 construct a positional relationship symmetrical to each other, as described above. This can be handled by using the same configuration as the sensor. The rationale for detecting only the shearing stress by making such an arrangement relationship of the strain gauges is as described above, and therefore will be omitted here.

With this configuration, it is possible to accurately detect the shearing stress due to only the braking force, and to eliminate any influence of other forces acting on the suspension, such as road surface frictional force, normal force, and lateral force. Thereby, the accuracy of sensing can be individually improved. Further, since the braking force is equivalent to the frictional force generated between the brake shoe 9 and the brake disc 8, whether the braking force directly acting on the wheels is accurately transmitted according to the actual brake operation. Can be monitored at any time, and by adopting this as one of the control parameters, accurate control can always be realized. The operation of how to actually implement the control will be described later.

FIG. 6 is a circuit block diagram of a brake assist device according to the present invention. The brake assist device includes a CPU (central) for controlling the entire device.
processing unit) 33, CPU33
(Random) used as work memory for
access memory) 34 and a ROM (read only memory) storing various programs and data.
emory) 37 and a control device 39 including an interface 38 for controlling signal transmission and reception between the CPU 33 and output devices such as sensors and solenoid valves.
The interface 38 has a function of converting an input analog signal into a digital signal, a function of converting an output digital signal into an analog signal, and the like. The interface 38 includes a brake pedal force F acting on a brake pedal. A pedal force detection sensor 10 that outputs a proportional voltage, a friction force detection sensor 7 that outputs a voltage proportional to the braking force FB, and a notification unit that notifies information based on output signals obtained from these sensors to persons inside and outside the vehicle. 40
An electromagnetic direction switching valve 41 for switching a path to a main or auxiliary operating fluid pressure source for each wheel, and an electromagnetic direction switching valve 42 for switching a path for operating fluid pressure to an auxiliary brake device represented by a parking brake or the like. And a fluid pressure control valve 43 for controlling a fluid pressure acting on the brake device.

FIG. 7 is a virtual circuit block diagram realized by the CPU 33 being operated based on the program stored in the ROM 37.
V _F calculation unit 44, an emergency braking start determination means 45, alpha calculation means 46, P calculating means 47, Oyopi solenoid valve control unit 48
Has been realized. These circuits are operated by the CPU 33 when the brake pedal of the vehicle is depressed.
By executing a control program stored in the. The depression of the brake pedal is determined based on the pedaling force detection sensor 10 attached to the brake pedal,
The PU 33 determines.

[0060] _{V F} calculation unit 44, pedal force sensor 10
Based on the brake pressing force F which is input through the interface 38 from, it calculates a depression speed parameters V _F of the brake pedal. Specifically, the brake depression force F is monitored at predetermined intervals, and the slope of the locus of the brake depression force is calculated based on the difference between the current brake depression force F and the brake depression force F at a point in time that is traced back in the past by the predetermined period. . That is,
The depression speed parameters V _F of the brake pedal, pursuant to the time change amount of the brake pressing force F.

[0061] emergency braking determination means 45, _{V F} computing means 4
4 according to the magnitude relation of the first peak value of the depression speed parameters V _F of the computed brake pedal by estimates emergency brake of the driver's will, and generates an emergency brake start signal. Specifically, sequentially monitors the depression speed parameter V _F is the time variation of the brake pressing force F, by comparing the first threshold value A1, which is set in advance, the driver's intention is the emergency braking or normal braking located in either the judges, depression speed parameter V _F is the solenoid valve control unit the emergency brake start signal at the stage of reaching a first threshold value A1 48
Output to Note that the first threshold value A1 is determined in advance in a range sufficiently larger than the depressing speed at the time of normal pedal operation, and is stored in the ROM 37.

The α calculating means 46 calculates a proportional coefficient α = FB / F based on the brake pedal force F and the brake force FB input from the pedal force detection sensor 10 and the friction force detection sensor 7 via the interface 38. .

The P calculating means 47 calculates the target fluid pressure P supplied from the auxiliary operating fluid pressure source by receiving the auxiliary mode switching signal from the electromagnetic valve control means 48. Specifically, when the solenoid valve control means 48 determines that a situation in which the driver cannot depress the brake pedal strongly has occurred, the brake depression force F from the depression force detection sensor 10;
A difference value A2-F from the second threshold value A2 according to the maximum value of the brake depression force is calculated, and a value α (A2-F) obtained by multiplying the difference value A2-F by the proportionality coefficient α from the α calculation means 46 is calculated. ) Is determined as the target fluid pressure P supplied from the auxiliary operation fluid pressure source. The second threshold value A2 according to the maximum value of the brake pedal force is determined in advance in accordance with, for example, the maximum value of the pedal force that a general adult male can depress the brake pedal.
It is stored in the OM 37.

The solenoid valve control means 48 determines the occurrence of a situation in which the driver cannot depress the brake pedal strongly, and starts operating the auxiliary operating fluid pressure source. Specifically, when it is determined by the emergency braking determination means 45 that the driver's will is in emergency braking, the brake depression force F from the depression force detection sensor 10 is monitored as needed, and the brake at the time of reaching the convergence state is monitored. If the pedaling force F is smaller than the second threshold value A2 corresponding to the maximum value of the brake pedaling force, it is determined that the driver cannot strongly depress the brake pedal, and the energized state of the solenoid of the electromagnetic direction switching valve 41 is switched. The auxiliary operation fluid pressure source is operated, and the auxiliary mode switching signal is transmitted to the P operation means 4.
7 is output.

Further, based on the target fluid pressure P of the auxiliary operation fluid pressure source from the P calculating means 47, the solenoid valve control means 48 determines the energized state of the solenoid of the hydraulic pressure control valve 43 provided for each wheel. Control.

Further, the solenoid valve control means 48 determines the state in which the driver deliberately depressed the brake pedal because the driver has secured the safety, and stops the operation of the auxiliary operation fluid pressure source. Specifically, in a situation where the auxiliary operation fluid pressure source is operating, the brake depression force F from the depression force detection sensor 10 tends to decrease, and slightly exceeds the second threshold value A2 corresponding to the maximum value of the brake depression force. 3rd with small absolute value
Is deviated from the threshold value A3, the driver determines that the driver has deliberately depressed the brake pedal, and switches the energization state of the electromagnetic direction switching valve 41 and the hydraulic pressure control valve 43 to switch the auxiliary operation fluid pressure source. The operation is stopped, and the mode is switched to the normal brake control using only the fluid pressure generated from the master cylinder as the main working fluid pressure source.

Further, the solenoid valve control means 48 judges the occurrence of the fade phenomenon and starts the operation of the auxiliary operation working fluid source. Specifically, the proportional coefficient α from the α calculating means 46
However, if the absolute value is smaller than the fourth threshold value A4, the frictional heat generated by the contact between the brake shoe 9 and the brake disk 8 is transmitted to the working fluid, and the viscosity of the working fluid is reduced. And judge that the brake braking force that restrains the wheels is not working properly,
The energized state of the solenoid of the electromagnetic directional switching valve 41 is switched to operate the auxiliary operating fluid pressure source.

Further, the solenoid valve control means 48 determines the occurrence of the fade phenomenon and starts the operation of the auxiliary brake device. Specifically, the proportionality coefficient α from the α calculation means 46 is maintained in a state smaller than the fourth threshold value A4 having a slightly smaller absolute value, irrespective of the operation of the auxiliary operation fluid pressure source described above. In this case, the brake device is in a state where it fails to function effectively due to a failure or the friction coefficient between the brake disk 9 and the brake disk 8 is sharply increased due to frictional heat generated by the contact between the brake shoe 9 and the brake disk 8. Lower
When it is determined that the brake braking force for restraining the rotation of the wheels is not properly acting, the energized state of the solenoid of the electromagnetic directional switching valve 42 is switched, and an auxiliary brake device represented by a parking brake or the like is operated. A warning is given to the person inside and outside the vehicle via the notification means 40 about the occurrence of the fade phenomenon.

As the informing means 40, for example, means for appealing to a person outside the vehicle such as a sound or a warning may be used, or a person such as a monitor or a lamp may be used for a person outside the vehicle. May be used.

That is, the pedaling force detection sensor 10 comprises an arbitrary number of first sensors capable of obtaining pedaling force information according to the brake pedaling force F based on the operation force artificially or mechanically applied to the brake pedal. ing. The frictional force detection sensor 7 constitutes an arbitrary number of second sensors capable of obtaining frictional force information according to the brake force FB generated when the brake shoe 9 presses the brake disk 8. V _F calculation unit 44 constitutes a brake pedal force change rate calculating means for calculating a slope of the locus of pedal force information from the first sensor. The α calculating means 46 constitutes a proportional coefficient calculating means for calculating the ratio between the pedaling force information from the first sensor and the friction force information from the second sensor. The P operation means 47 constitutes an auxiliary operation fluid pressure operation means for calculating a target value of the auxiliary operation fluid pressure supplied from the auxiliary operation fluid pressure source to the brake device according to the pedaling force information from the first sensor. .

During operation of the brake device, the solenoid valve control means 48 has reached a convergence state in which the brake depression force F from the first sensor has not reached the second threshold value corresponding to the maximum value of the brake depression force. Working fluid control means for starting operation of the auxiliary working fluid pressure source at a point in time is configured. The electromagnetic valve control means 48 constitutes a working fluid control means for controlling the fluid pressure of the auxiliary working fluid pressure source based on the target value P of the fluid pressure calculated by the auxiliary working fluid pressure calculating means. Further, the solenoid valve control means 48 operates while the auxiliary operation fluid pressure source is operating.
When the brake depression force F from the first sensor becomes smaller than a third threshold value A3 having a slightly smaller absolute value than the second threshold value A2 corresponding to the maximum value of the brake depression force, the operation of the auxiliary operation fluid pressure source is started. Is stopped, and working fluid control means for switching to normal brake control is configured.

Further, during operation of the brake device, the solenoid valve control means 48 sets the proportional coefficient α from the proportional coefficient calculating means to:
When the absolute value becomes smaller than the fourth threshold value A4, which is smaller than the fourth threshold value A4, it is determined that a fade phenomenon has occurred in the brake device, and a fade phenomenon control means for operating the auxiliary operation fluid pressure source is constituted. I have. Further, the solenoid valve control means 48 keeps the proportional coefficient α from the proportional coefficient calculating means smaller than the fourth threshold value A4 having a slightly smaller absolute value, regardless of the operation of the auxiliary operation fluid pressure source. If it is maintained, it is determined that the brake device itself cannot effectively perform its function due to the failure of the brake device or the progress of the fade phenomenon, and the auxiliary brake control means for operating the auxiliary brake device is configured. I have. Further, the solenoid valve control means 48 constitutes a warning notifying means for notifying the inside and outside of the vehicle of the occurrence of the fade phenomenon.

Next, the operation of the above brake assist device,
The reason why excellent braking performance is exhibited by the operation and the operation will be theoretically considered.

FIG. 8 is a waveform diagram showing a change in the general brake depression force F acting on the brake pedal 1 at the time of emergency braking and at the time of normal braking. As is clear from FIG. In, the brake depression force F rises with a substantially constant inclination (0 to t2), but its gradient becomes gentler as the brake depression force approaches the maximum depression force Fmax which is the maximum value (t2 to t3). The convergence state is reached (after t3). On the other hand, at the time of emergency braking, the initial rising gradient is extremely large, and reaches a convergence state in a period (t1) earlier than that at the time of normal braking.

[0075] Thus, immediately after the driver starts the pedal operation, based on the brake pressing force F from the depression force detecting sensor 10, and sequentially calculates the depression speed parameter V _F is its time rate of change, the calculation result Output to the emergency braking determination means 45. In emergency braking determination unit 45 monitors the depression speed parameters V _F immediately after the start pedal,
Once beyond the A1 is a sufficiently large value than the depression speed parameter V _F during normal braking, the pedal operation intention of the driver is determined that there is an emergency braking. A1 in FIG. 8 corresponds to the first threshold value and means a reference boundary line for determining whether or not the driver's intention is to operate the pedal for emergency avoidance.

Incidentally, the brake depression force F is correlated with the brake braking force acting on the brake device through the working fluid pressure generated in the master cylinder connected to the brake pedal 1, and the maximum depression force Fmax is ,
It changes according to the gender and skill of the driver, the situation in which the person is placed, and the like. By way of example, a driver, such as a woman or an elderly person, who is weak or unfamiliar with emergency braking, or who has panicked, may depress the pedal quickly but not strongly. Under such circumstances, the brake pedaling force F is relatively small, and as a result, the braking force for suppressing the rotation of the wheels also becomes low, and the braking distance, which is one of the factors causing a serious accident, becomes longer. Occurs.

Now, FIG. 9 shows that the brake pedal 1 is
An embodiment of the brake assist device in a state where the driver has depressed until t6) will be described in chronological order. First, compared with the depression speed parameters V _F and the first threshold value A1 is the time rate of change of the brake pressing force F, when the V _F has reached A1 (t
In 4), the start of emergency braking is determined. Then, when the convergence state is reached in a state where the brake pressing force F has not reached the second threshold value A2, the time (t5) is determined as the control start timing of the auxiliary operation fluid pressure source, and the auxiliary operation fluid What is necessary is just to generate the pressure control signal a. Converging state of the brake pressing force F, for example depression speed parameter V _F, which is also the time differential value of the brake pressing force F is, during a predetermined time Delta] t, is determined by continuing to maintain the state close to zero or zero.

That is, the second threshold value A2 is a limit value of the brake depression force necessary for effectively applying the brake braking force at the time of emergency braking, and the driver's depressing force on the brake pedal 1 is weak. If the value cannot be reached, the auxiliary working fluid pressure source assists the shortage that cannot be satisfied with the main working fluid pressure source alone.
Effective braking force can be obtained. The fluid pressure supplied from the auxiliary operation fluid pressure source is obtained by adding a later-described proportional coefficient αF to the insufficient pedal effort ΔF at the time (t5) when the signal a is generated.
, The fluid pressure P given by multiplying
The hydraulic pressure control valve 43 controls each wheel. In addition, the second threshold value A2 is defined as, for example, about 80% of a statistical value of a brake depression force with which a general adult male depresses a brake pedal during emergency braking.

Here, the configuration and operation of the auxiliary operation fluid pressure source will be described with reference to FIG. FIG. 12 is an example of a piping system diagram relating to the brake assist device of the present application. As a premise, the brake assist device is controlled by the control device 39. The input unit S7 of the control device 39 includes a pedaling force detection sensor 10, a frictional force detection sensor 7 for each wheel, a hydraulic pressure sensor 56 for detecting an operating fluid pressure of the accumulator 53,
A hydraulic pressure sensor 55 for detecting an operating fluid pressure supplied to the brake device for each wheel is connected to the output unit 58.
An electromagnetic direction switching valve 41 and a hydraulic pressure control valve 43 provided for each wheel are connected.

The auxiliary working fluid pressure source proposed in the present application is provided independently of the main working fluid pressure source constituted by the master cylinder 50, and is provided in the reservoir 51 for storing the working fluid and the reservoir 51. It comprises a pump 52 for pumping the stored working fluid, and an accumulator 53 for applying a certain range of pressure to the pumped working fluid and storing it. Electromagnetic directional control valve 41 in the state described above
The operation of the solenoid valve control means 4 will be described with reference to FIG.
Reference numeral 8 denotes a master cylinder 50 that switches the energized state of a solenoid of an electromagnetic direction switching valve 41 to generate a main working fluid pressure based on a driver's pedal operation, and a hydraulic pressure control valve 43 provided independently of the master cylinder 50. A line is connected to the controlled auxiliary working fluid pressure source.

Next, when the driver recognizes that the driver has avoided danger and intentionally loosens the depression of the pedal, the brake depression force F starts to decrease in accordance with the degree of the release. Here, when the brake depression force F decreases beyond the third threshold value A3 having a slightly smaller absolute value than the second threshold value A2, it is determined that the driver has intentionally released the brake pedal. The time (t6) is determined to be the control end timing of the auxiliary operation fluid pressure source, and the electromagnetic valve control unit 48 instructs the stop of the operation of the auxiliary operation fluid pressure source.

That is, the third threshold value A3 means that the driver intentionally loosened the pedal operation to ensure safety, or that the driver unconsciously loosened the pedal because he could not maintain the state of depressing the pedal strongly. This is a boundary line for determining whether or not the error has occurred, and is set to, for example, 80% of the second threshold value A2. The operation of the electromagnetic direction switching valve 41 in this state will be described with reference to FIG.
The energized state of the solenoid of the electromagnetic directional switching valve 41 is switched to close the conduit leading to the auxiliary working fluid pressure source and to communicate only with the pipeline leading to the main working fluid pressure source.

By repeating such an operation until the vehicle stops, an effective braking force according to the situation is always supplied to the brake device even in a situation in which the need for emergency braking occurs. .

Next, the operation of the brake assist device having the above-described circuit block when a fade phenomenon occurs on the brake device side will be described with reference to FIG. Generally, as described above, there is a correlation between the brake pedal force F and the brake force FB, but the relationship sometimes breaks down. As an example, if the brake operation is performed continuously on a steep hill, even though the brake pedal 1 is depressed,
There is a situation in which the braking force transmitted to the brake device tends to decrease naturally. The factors are
The frictional heat generated by the contact between the brake shoe 9 as the friction member and the brake disc 8 as the rotating body lowers the friction coefficient between the two, or the frictional heat is transmitted to the working fluid to lower the viscosity. This causes a pressure decrease, and such a phenomenon is generally called a fade phenomenon. In other words, 2
There are various types of factors, and in order to distinguish between them, the former is referred to as a fade phenomenon due to deterioration of the friction coefficient, and the latter is referred to as a fade phenomenon due to heat propagation.

These fading phenomena directly affect the mechanism of the brake device itself, and only monitor the brake depressing force F as in the prior art, or use a hydraulic system provided in front of the brake device. It is unclear whether the braking force is properly transmitted to the brake device simply by controlling the brake device by using the sensor 55 in combination, and therefore, it is difficult to prevent an unexpected situation such as a fade phenomenon. I couldn't respond enough.

Therefore, immediately after the start of the braking, a correlation existing between the two parameters is derived based on the brake depression force F from the depression force detection sensor 10 and the braking force FB from the friction force detection sensor 7. Monitoring the relationship at any time is very effective as means for detecting an abnormal state such as a fade phenomenon. Note that the correlation established between the brake depression force F and the brake force FB is generally approximately expressed by, for example, a linear function FB = αF.

FIG. 10 shows an embodiment of a brake assist device in the event of a fade phenomenon in chronological order. When the brake pedal 1 is depressed, the brake depression force F increases substantially linearly. On the other hand, the brake force FB also starts to increase due to the transmission delay of the brake system. During the first period (0 to t7), the waveform of the proportionality coefficient α is disturbed due to the transmission delay of the brake system. However, since the fade phenomenon itself operates the brake continuously for a long time, Since this occurs, this may be ignored in a control manner. The proportional coefficient α shown in FIG. 10 is a ratio between the brake force FB and the brake depression force F.

When the operation of depressing the brake pedal 1 is continued, the brake depression force F continues to increase, but the gradient of the increase in the brake force FB gradually decreases, and eventually the tendency to decrease decreases. appear. Considering respect Transition of proportionality coefficient alpha for this course, the time when the brake pressing force F and braking force FB are both stable upward trend (t7 to t8), the proportional coefficient alpha is almost constant value alpha ₁ However, as the inclination of the increase in the braking force FB becomes smaller, the proportional coefficient α starts to show a decreasing tendency. Eventually, when the braking force FB turns to a decreasing tendency, the decreasing tendency of the proportional coefficient α rapidly progresses. Here, by comparing the proportional coefficient α with A4 which is the fourth threshold value, the point in time at which α has decreased to A4 (t9) is determined as the control start timing of the auxiliary operation fluid pressure source, and The control signal b may be generated to compensate for the lost braking force.

Incidentally, the control signal b of the auxiliary operation fluid pressure source
Is generated to operate the auxiliary operation fluid pressure source, there is a situation in which the proportionality coefficient α is maintained to be smaller than the fourth threshold value A4. This is a state in which the brake device itself fails to function effectively due to a failure, or the friction heat, which is a cause of the fading phenomenon, is further propagated to restrain the rotation of the wheel. This is because the friction coefficient between the brake disk and the brake disk 8 is rapidly reduced (a fade phenomenon occurs due to a decrease in the friction coefficient). In such a situation, the operation of the auxiliary operation fluid pressure source is merely for preventing further loss of the braking force, and the restraint control of the wheel rotation is performed from the conventional brake device side. Must be switched to the independently provided auxiliary brake device side.

That is, during a certain period of time ΔT from the start of operation of the auxiliary working fluid pressure source, the proportionality coefficient α is changed to the fourth threshold value A4.
It is determined that the time (t10) at which the auxiliary braking force continues to be smaller than this is the control start timing of the auxiliary brake device, and the control signal c is generated to assist and increase the brake braking force that the auxiliary brake force _FBsub has lost. In other words, the proportional coefficient at the moment alpha is, first from the proportional coefficient alpha ₁ are sufficiently stable 4
If the operating fluid pressure falls within the range up to the threshold value A4, it is determined that the operating fluid pressure generated in response to the driver's operation of the pedal is accurately transmitted to the brake device and converted into the braking force, To maintain the brake braking by the control method described above. Further, the proportional coefficient alpha is, if it is a departure from the range of alpha ₁ to A4, it is determined that the braking force according to the working fluid pressure to the brake device by fade is not applied, the auxiliary The operation of the working fluid pressure source or the auxiliary brake device is determined, and information on the occurrence of the fade phenomenon is notified to a person inside and outside the vehicle through a notification unit 40. The fourth threshold A4 is a parameter that is governed by the proportionality factor alpha ₁ stable state, it means a boundary line indicating a braking limit of the brake device.

The auxiliary brake device is for compensating for the braking force lost by the brake device that has stopped functioning due to the fade phenomenon. For example, a parking brake or an engine brake may be employed.

FIG. 11 is a circuit block diagram realized by a CPU 33 according to another embodiment of the present invention. In this embodiment, the solenoid valve control means 48 includes:
Instead of determining the target value P of the working fluid pressure supplied from the auxiliary working fluid pressure source in accordance with the brake pressing force F from the pedaling force detection sensor 10, <distribution of the auxiliary working fluid pressure is performed based on the maximum value Fmax of the brake pressing force. The working fluid pressure is changed according to the rate β. Further, the solenoid valve control means 48 stores and manages the maximum value Fmax of the brake depression force as personal information of the driver. Further, the solenoid valve control means 48 evaluates the driver's accident avoidance ability according to the maximum value Fmax of the brake depression force, and notifies the driver of this. The other operations performed by the solenoid valve control means 48 are the same as those of the circuit block shown in FIG. Further, in this embodiment, a β calculating means 49 is newly provided, and the β calculating means 49 is provided.
Determines the ratio of the fluid pressure to both the main and auxiliary working fluid pressure sources. Specifically, a difference value between the maximum depression force Fmax of the brake depression force managed by the solenoid valve control means 48 according to the depression force detection sensor 10 and a preset threshold value is obtained, and the difference value is calculated by the above-described threshold value. The division ratio β is calculated by the division. Other operations are the same as those of the circuit block shown in FIG. With this configuration, it is not necessary to set the target value of the auxiliary working fluid pressure every time the emergency braking is performed, and an appropriate working fluid is always distributed to the main and auxiliary working fluid pressure sources and supplied to the brake device. I can do it.

That is, the β calculating means 49 obtains a difference value between the maximum depressing force Fmax of the brake depressing force managed by the solenoid valve control means 48 according to the depressing force detecting sensor 10 and a preset threshold value. By dividing the value by the above-mentioned threshold value, a fluid pressure distribution ratio calculating means for obtaining the distribution ratio β of the brake braking force of the main and auxiliary operating fluid pressure sources is constituted. The solenoid valve control unit 48 is provided with the past pedal force detection sensor 10.
The maximum value is calculated based on the input of the pedaling force information from
This constitutes maximum pedaling force calculation means for recording and managing this as personal information of the driver. Further, the solenoid valve control means 48
Constitutes a warning notification unit that evaluates the driver's accident avoidance ability in accordance with the maximum value of the brake depression force from the maximum depression force calculation means and notifies the driver of this. Further, the solenoid valve control means 48 constitutes a working fluid control means for controlling the working fluid in accordance with the distribution ratio β from the fluid pressure distribution ratio calculating means.

Hereinafter, the reason why excellent braking performance can be obtained by the above operation will be considered theoretically.

The major cause of a serious accident is distraction due to running at excessive speeds and observation while driving a vehicle. This is accompanied by overconfidence because the individual driver does not know and does not know his or her exact driving skills. By the way, the original function of the brake device is to reduce the speed and stop the vehicle immediately when it is determined that a dangerous state occurs if the vehicle continues to travel. Since it is clear that the operation of the brake device depends on the driver's operation of depressing the brake pedal, the maximum depression force Fmax, which is one of the operation amounts, is adopted as one of the parameters representing the exact driving skill of the driver. Can be done.

The maximum depression force Fmax is determined according to the operation of depressing the brake pedal during the past emergency braking.
That is, the solenoid valve control means 48 has a predetermined initial reference value in advance, compares it with the brake depression force F from the brake depression force detection sensor 10 as needed, and sequentially updates the larger absolute value as the reference value. Keep doing. The reference value finally determined in such a procedure is set as the maximum pedaling force Fmax, and this is stored as personal information of the driver. The held maximum pedaling force Fmax is adopted for the next and subsequent controls. The initial reference value is, for example, a sufficiently small value of zero or a value close thereto. The initial reference value here is a value set only at the time of the first emergency braking, and thereafter, the maximum pedaling force Fmax is set and stored in the ROM 37.

The method of setting the maximum pedaling force Fmax is not necessarily limited to emergency braking. For example, in a situation where the vehicle is completely stopped, the driver operates the pedal assuming emergency braking. It may be something.

The maximum pedal force Fma set in this way
x is compared with a predetermined second threshold value A2, and depending on whether or not the value is smaller than the threshold value, the driver's skill for avoiding an accident, that is, sufficient braking braking force can be contributed during emergency braking. It is possible to determine whether or not. If the maximum pedaling force Fmax is smaller than the second threshold value A2, it means that the driver's skill in avoiding an accident is low, and this is reported as a warning to the notification means 4.
By giving advance notice through 0, the driver's self-confidence can be prevented and attention can be given to an accident. Since the setting and definition of the second threshold value A2 are as described above, the details are omitted here.

Next, the operation of the brake assist device using the maximum depression force Fmax will be described with reference to FIG.
In emergency braking, in a situation where the driver's depression force on the brake pedal 1 is weak or cannot be maintained, the brake depression force is supplied from an auxiliary operation fluid pressure source provided independently of the main operation fluid source comprising the master cylinder. Detection sensor 10
As described above, the operation of supplying the fluid pressure according to the target value calculated based on the brake pedaling force F from the above and assisting and increasing the insufficient or lost brake braking force is as described above. The target value of the fluid pressure can be set using the pedaling force Fmax.

Specifically, first, the maximum pedaling force Fmax, which is the driver's personal information stored in the ROM 37, and the second
Is the difference value A2-Fmax between the threshold value A2 and the insufficient pedal effort Δ
Calculate F. The ratio between the insufficient pedal effort ΔF and the second threshold A2 is calculated based on the following equation (2). This ratio (A
2-Fmax) / A2 corresponds to a distribution ratio β of the auxiliary operation fluid pressure generated by operating the auxiliary operation fluid pressure source with respect to the main operation fluid pressure. That is, the ratio (A2-F
max) / A2 may be set as the distribution ratio β, and the target value P may be determined by substituting the distribution ratio into the following Expression 3. In the following formula 3, F is the brake pedal force from the pedal force detection sensor 10, and α is the proportional coefficient obtained by dividing the brake pedal force F from the pedal force detection sensor 10 and the brake force FB from the frictional force sensor 7. The proportionality coefficient α represents a conversion coefficient of the operation amount of the brake pedal 1 into the actual braking force acting on the brake device. That is, αF, which is the product of the proportionality coefficient α and the brake depression force F, indicates the main working fluid pressure generated in the master cylinder 50 in response to the driver depressing the pedal.

[0101]

[0102]

In this manner, the control judgment of the working fluid based on the brake pedaling force F from the pedaling force detection sensor 10 and the various threshold values, as described above, can be performed by predetermining various parameters and set values. Implementing the control of the working fluid using both the predictive control technology and the learning control technology based on the past experience such as the case of using the maximum pedaling force Fmax is one control. Therefore, a plurality of confirmation mechanisms can be established, and control with higher safety can be realized with less erroneous determination.

Further, a driver having a low maximum pedaling force Fmax can consider that the depression of the brake pedal 1 itself is entirely small, so that not only during emergency braking,
Even during normal braking, by supplying auxiliary working fluid pressure according to the distribution ratio β in addition to the main working fluid pressure from the master cylinder, always appropriate brake control according to the skill and characteristics of the driver Can be realized. That is,
By using the maximum pedaling force Fmax based on the past experience as personal information of the driver, it is not necessary to calculate the target value P of the auxiliary operating fluid pressure every time the emergency braking is determined, and the burden on the CPU 33 is reduced. In addition to the uniform control ignoring the characteristics of the driver as in the related art, the control according to the individual characteristics of the driver such as various genders and ages can be realized.

In the present embodiment, the description has been made mainly on the control using the brake fluid as the working fluid. However, the present invention is not limited to this. For example, the brake control using the air pressure instead of the brake fluid is performed. Can be similarly applied.

Further, a vehicle employing this embodiment is:
Even in the case of an electric vehicle driven to run by an electromagnetic motor, the same effect can be obtained by applying the same. In this case, the working fluid pressure source is replaced with an electromagnetic motor, and the brake braking force supplied from the electromagnetic motor is controlled based on the brake depression force F from the depression force detection sensor 10 and the braking force FB from the friction force detection sensor 7. Good. Specifically, at the time of pedal operation, the pedaling force detection sensor 1
And the frictional force detection sensor 7
The braking force FB is monitored from time to time to determine a proportional coefficient α, which is a divided value of the two. When the proportional coefficient α is smaller than a predetermined second threshold value A2, an appropriate braking braking force is applied to the wheels. It is only necessary to determine that it is not acting and drive the electromagnetic motor to recover the brake braking force. Also,
If the proportional coefficient α has recovered to the second threshold value A2, it is determined that an appropriate brake braking force is acting on the wheels, and the current control state may be maintained. The configuration and operation of a virtual circuit block realized by the CPU 33 in the electric vehicle are the same as those shown in FIG. 7 or FIG.

[0107]

The present invention makes it possible for a driver to make a decision to shift to emergency braking for the purpose of avoiding an accident, and to make a decision to return from an emergency braking state to a normal braking operation state by ensuring safety. In a brake assist device that is promptly and directly reflected in control, it monitors at any time whether the brake braking force according to the driver's pedal operation is properly transmitted to the brake device side, and if not, an appropriate brake braking force By assisting and increasing to recover to,
An abnormal situation such as a fade phenomenon can be avoided beforehand, and a remarkable effect can be obtained in that the brake performance including the ABS is maximized without malfunction.
Further, by providing such a brake assist device, it is possible to realize brake control according to individual characteristics of a driver such as age and gender, and ABS
This significantly improves the accuracy of brake control including the above. Furthermore, by providing such a brake assist device, it is possible to increase the driver's own awareness of danger in an accident, and to pay particular attention to elderly and female drivers who are assumed to have a weak force to depress the brake pedal. This has the special effect of preventing the occurrence of accidents before they occur.

[Brief description of the drawings]

FIG. 1 is a mounting diagram of a pedaling force detection sensor according to the present invention.

FIG. 2 is an external view of a tread force detection sensor according to the present invention.

FIG. 3 is a diagram illustrating a change tendency of each strain gauge corresponding to a stress direction in a pedaling force detection sensor according to the present invention.

FIG. 4 is a mounting view of the frictional force detection sensor according to the present invention.

FIG. 5 is an external view of a frictional force detection sensor according to the present invention.

FIG. 6 is a circuit block diagram of a brake assist device according to the present invention.

FIG. 7 is a virtual circuit block diagram realized by a CPU provided in the brake assist device according to the present invention.

FIG. 8 is a graph showing changes in brake pedal force and brake pedal depression speed during emergency braking and normal braking.

FIG. 9 is a signal waveform diagram of each part in the brake assist device according to the present invention.

FIG. 10 is a signal waveform diagram of each part in the brake assist device according to the present invention.

FIG. 11 is a virtual circuit block diagram realized by a CPU provided in a brake assist device according to another embodiment.

FIG. 12 is an example of a brake system diagram in the brake assist device according to the present invention.

FIG. 13 is a signal waveform diagram of each part in the brake assist device according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Brake pedal 2 Brake pedal arm part 5 hole 7 Friction force detection sensor 10 Treading force detection sensor 33 CPU 34 RAM 37 ROM 38 Interface 40 Notification means 41 Electromagnetic direction switching valve provided for each wheel 42 Provided in auxiliary brake device electromagnetic directional control valve 43 pressure control valve 44 V _F computing means 45 the emergency brake determining means 46 alpha calculating means 47 P calculating means 48 solenoid valve control unit 49 beta calculating means

Claims (10)

[Claims] 1. An arbitrary number of brake pedals for detecting a shear stress acting on an arm portion of a brake pedal by an operation force artificially or mechanically applied to a brake pedal of a vehicle as a brake pedal force acting on the brake pedal. 1 sensor, a rotating part that rotates with the wheel, and a non-rotating part that is brought into contact with the rotating part and suppresses the rotation of the wheel. An arbitrary number of second sensors for detecting the frictional force acting between the first and second sensors, the pedaling force information corresponding to the brake pedaling force obtained from the first sensor, and the pedaling force information corresponding to the frictional force obtained from the second sensor. Control means for adjusting a brake braking force acting on the wheel based on the frictional force information. 2. The control means calculates a ratio between the treading force information and the frictional force information based on the treading force information and the frictional force information, and when the ratio deviates from a preset range. 2. The brake assist device according to claim 1, wherein the brake assist device adjusts the braking force acting on the wheels to increase. 3. The control means determines whether the brake device has failed or has reached a braking limit based on the pedaling force information and the frictional force information. 3. The brake assist device according to claim 1, wherein the brake assist device is adjusted to increase the brake braking force by operating an auxiliary brake device different from the device. 4. 4. A notifying means for notifying that the brake device has failed or has reached a braking limit, and the control means has a function of notifying the notifying device when the braking device has reached a failure or a braking limit. The brake assist device according to claim 3, which is operated. 5. An arbitrary number of brake pedals for detecting a shear stress acting on an arm portion of the brake pedal by an operation force artificially or mechanically applied to a brake pedal of a vehicle as a brake pedal force acting on the brake pedal. And determining a maximum value of the brake pedaling force by the driver up to the present time based on the pedaling force information corresponding to the brake pedaling force obtained from the first sensor when the driver depresses the brake pedal. A maximum tread force determination storage unit that stores the maximum value as the driver's maximum tread force, based on the maximum tread force stored in the maximum tread force determination storage unit and a predetermined reference value, A control device for adjusting a braking force acting on a wheel. 6. The control unit according to claim 5, wherein when the maximum pedal effort is smaller than the reference value, the control unit adjusts the brake braking force according to a difference between the maximum pedal effort and the reference value.
A brake assist device according to item 1. 7. The brake assist device according to claim 5, further comprising an informing unit that informs the driver of the maximum pedaling force. 8. The sensor according to claim 1, wherein the first sensor is constituted by a strain gauge, and is embedded and fixed in a hole formed at a position including a stress center band existing in the brake pedal. The brake assist device according to any one of the above. 9. The brake assist device according to claim 1, wherein the first sensor is mounted on a connecting member that connects the brake pedal and a master cylinder. 10. The vehicle according to claim 1, wherein the vehicle is an electric vehicle that is driven by an electric motor, and wherein the control unit adjusts the brake braking force by controlling the electric motor. Brake assist device.