JP2003291790A - Device for controlling distribution of braking force of vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To properly distribute a braking force to each wheel according to a static load of each wheel by properly estimating the static load of each wheel with an inexpensive and simple constitution. <P>SOLUTION: A braking stiffness of each wheel (such as FR) is calculated on the basis of output of a wheel speed sensor (WS1 and the like), to estimate the static load of each wheel based on the calculation results while a vehicle is linearly traveling at approximately constant speed. According to the static load, a braking force of each wheel is controlled to adjust distribution of the braking force. A dynamic load between respective wheels may be calculated on the basis of detection results of a lengthwise acceleration sensor (XG) and a lateral acceleration sensor (YG) and the estimation result of the static load, to control the braking force of each wheel according to the dynamic load. Only when a pneumatic pressure of a tire is detected and it is within a predetermined pressure range, estimation of the static load may be permitted. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a braking force distribution control device that adjusts the braking force of each wheel of a vehicle to a predetermined relationship, and particularly distributes the braking force according to the static load of each wheel during normal running. And a braking force distribution control device.

[0002]

2. Description of the Related Art In general, when braking or turning operation is performed on a running vehicle, the load applied to each wheel varies in the front-rear direction and / or the lateral direction of the vehicle due to load movement. The load on each wheel at this time is called a dynamic load, and a braking force distribution control device is known as a device for controlling so as to distribute the braking force based on this.

For example, in Japanese Patent Laid-Open No. 2001-287635, the gradient of the friction coefficient μ between the wheel and the road surface is estimated as the road surface μ gradient value for each wheel based on the wheel speed, and the road surface μ of each wheel is estimated. A braking force distribution control device is disclosed which calculates a target braking force of each wheel based on a gradient value and a target braking force of a vehicle, and controls the braking force of each wheel based on the target braking force of each wheel. There is.

Further, in Japanese Unexamined Patent Publication No. 6-16117, a total longitudinal force, which is a sum of longitudinal forces applied to a plurality of wheels, is detected or set, and a share load ratio for each of a plurality of wheels with respect to a total vehicle weight is obtained. , A wheel longitudinal force that sets the target wheel longitudinal force to be applied to each wheel by distributing the total longitudinal force to each wheel according to the shared load ratio, and controls the longitudinal force of each wheel based on the target wheel longitudinal force A control method has been proposed, and an example in which the longitudinal force is a braking force is also disclosed.

[0005]

As described above, the braking force distribution control device is generally designed to distribute the braking force according to the load change of each wheel during braking or turning. From the above, it is contemplated to determine the dynamic load between the wheels and control the braking force based on the dynamic load. Therefore, for example, the above-mentioned Japanese Patent Laid-Open No. 2001-28763.
In the device described in Japanese Patent Publication No. 5, the road surface μ gradient value of each wheel is calculated in real time, but since it is usually processed in an extremely short cycle, the required calculation processing speed is necessarily increased. For this reason, an ordinary filter cannot be used as a noise countermeasure, and complicated arithmetic processing such as configuring a special filter that can be processed at high speed is required, resulting in an expensive device. Further, the load sensor used in one aspect of JP-A-6-16117 is also expensive.

Usually, in the braking force distribution control, when it is necessary to change the setting condition with respect to the initial value preset based on the vehicle weight, etc., the loading before the braking operation or the turning operation is carried out. This is the case where the load on each wheel fluctuates due to a change in load or a change in occupant. This change naturally changes the dynamic load, but the above-mentioned problem occurs when the braking force is distributed based on the change in the dynamic load. Therefore, first, the static load applied to each wheel during normal traveling (not during braking or turning) is estimated, the braking force distribution control is performed according to this, and further estimated as necessary. If the dynamic load is estimated based on the static load, it is not necessary to calculate in real time, and an inexpensive device can be used.

Therefore, the present invention appropriately estimates the static load of each wheel in a braking force distribution control device for a vehicle with an inexpensive and simple structure, and determines the braking force for each wheel according to the static load. The task is to allocate it appropriately.

[0008]

In order to solve the above-mentioned problems, according to a first aspect of the present invention, there is provided braking force generating means for generating a braking force applied to each wheel of a vehicle, and Wheel speed detection means for detecting the speed of each wheel, and at least the output of the braking force generation means is controlled according to the output of the wheel speed detection means to control the braking force of each wheel. In a vehicle braking force distribution control device having a braking force control means for adjusting the braking force distribution, a braking stiffness calculation means for calculating the braking stiffness of each wheel based on the output of the wheel speed detection means, Based on the calculation result of the braking stiffness calculation means while the vehicle is traveling straight at a substantially constant speed,
And a static load estimating means for estimating a static load of each wheel, wherein the braking force control means controls the braking force of each wheel according to an estimation result of the static load estimating means. It was done.

Here, the static load is a load applied to each wheel during normal traveling, not during braking or turning, and the braking stiffness calculating means when the vehicle is traveling straight at a substantially constant speed. Based on the braking stiffness that is the calculation result of, the static load estimating means estimates as follows.

First, the braking stiffness, which is also called the brake rigidity, changes depending on the tire block rigidity, the shape of the contact surface of the tire, etc., as described below. That is, the braking stiffness is represented by Sx, the shear constant of the tire tread (represented by Cx) is used as the tire block rigidity, and the width of the contact surface (represented by w) and the length of the contact surface (d) are used as the contact surface shape of the tire. Sx is as follows. ^{Sx = Cx · w · d 2} /2

The above braking stiffness Sx is
It can be represented by the gradient of the braking force (represented by Fk) with respect to the wheel slip ratio (represented by Sp) near the wheel slip ratio of zero. The gradient of the friction coefficient (μ) with respect to the wheel slip ratio Sp is proportional to the front-rear friction coefficient of the braking force Fk, so the μ gradient (the μ gradient when Sp = 0 is a static μ gradient,
Other μ gradients during traveling are referred to as dynamic μ gradients) and can be used in the processing described later. For example, in FIG. 8, the braking stiffness (Sxa) is large when the static μ gradient is large as shown by the solid line, and the braking stiffness (Sxb) is small when the static μ gradient is small as shown by the broken line. small.

Since the shape of the tire contact surface changes depending on the tire load on each wheel, the static μ
By estimating the gradient (thus, the braking stiffness Sx is estimated), the load ratio (load ratio of each wheel) to each wheel of the total load can be obtained. In the present application, the term wheel or tire is used for convenience of description, but the term wheel means a pneumatic rubber tire.

Further, as described in claim 2, a wheel cylinder mounted on each wheel of the vehicle to apply a braking force, a hydraulic pressure generator for supplying a brake hydraulic pressure to each wheel cylinder, and the hydraulic cylinder. A hydraulic pressure control device that is interposed between a pressure generation device and the wheel cylinder to control the brake hydraulic pressure of the wheel cylinder, a wheel speed detection unit that detects the speed of each wheel, and at least the wheel speed detection. The hydraulic pressure control device is driven according to the output of the means to control the brake hydraulic pressure supplied to the wheel cylinders to control the braking force of each wheel, and to adjust the braking force distribution between the wheels. In a braking force distribution control device including a power control means, a braking stiffness calculation means for calculating the braking stiffness of each wheel based on the output of the wheel speed detection means, A static load estimating means for estimating a static load of each of the wheels based on a calculation result of the braking stiffness calculating means when the vehicle is traveling straight at a substantially constant speed; and the braking force control means, If the braking force of each wheel is controlled according to the estimation result of the static load estimating means, it is particularly suitable for a hydraulic brake system.

Alternatively, as described in claim 3, braking force generating means for generating a braking force applied to each wheel of the vehicle, and wheel speed detecting means for detecting the speed of each wheel,
Target braking force calculation means for calculating the target braking force of each wheel based on at least the output of the wheel speed detection means and the target braking force of the vehicle, and the braking force generation based on the calculation result of the target braking force calculation means. A braking force distribution control device for a vehicle, comprising: a braking force control means for controlling the braking force of each wheel by controlling the output of the means to adjust the braking force distribution between the wheels; Based on the output of the braking stiffness calculation means for calculating the braking stiffness of each wheel, and the calculation result of the braking stiffness calculation means while the vehicle is traveling straight at a substantially constant speed, Static load estimating means for estimating a load, and the braking force control means controls the braking force of each wheel according to the estimation result of the static load estimating means. If configuration is suitable for electronically controlled brake system.

In each of the above braking force distribution control devices, as described in claim 4, longitudinal acceleration detecting means for detecting acceleration in the longitudinal direction of the vehicle and lateral acceleration for detecting acceleration in the lateral direction of the vehicle. A detection means, and a dynamic load estimation means for calculating a dynamic load between the wheels based on the detection results of the lateral acceleration detection means and the longitudinal acceleration detection means and the estimation result of the static load estimation means, The braking force control means may be configured to control the braking force of each wheel according to the estimation result of the dynamic load estimation means.

By the way, even if the tire air pressure fluctuates, the estimation result is the same as when the static load of each wheel fluctuates due to the change of the loading load or the fluctuation of the occupant. Therefore, such a case is excluded. It is necessary to take action. Therefore, in each of the above braking force distribution control devices, as described in claim 5, at least an air pressure detecting means for detecting the air pressure of the tire of the wheel in front of the vehicle is provided, and the air pressure detecting means detects the air pressure. It is preferable that the apparatus includes an estimation start determination unit that allows the static load estimation unit to estimate only when the air pressure is within a predetermined pressure range.

Further, normally, the static load should be substantially the same for the left and right wheels, but when one wheel is replaced with an emergency tire, the μ gradient changes. This can be detected as a change in tire air pressure if configured as described in claim 5, but if configured as follows, replacement with an emergency tire without providing air pressure detection means, etc. It is possible to determine anomalies due to, and it is possible to prohibit the estimation of static load. That is, μ for the left and right wheels
The static load may be estimated only when the difference in gradient is less than a predetermined value (or the difference in braking stiffness between the left and right wheels is less than a predetermined value).

In each of the above braking force distribution control devices, the longitudinal acceleration detecting means for detecting the longitudinal acceleration of the vehicle and the brake operation for detecting the operation of the brake operating member for driving the braking force generating means. The vehicle speed difference between the left and right wheels of the vehicle detected by the wheel speed detection means is less than a predetermined speed, the longitudinal acceleration of the vehicle detected by the longitudinal acceleration detection means is less than a predetermined acceleration, and The brake operation detecting means may include an estimation start determining means that allows estimation by the static load estimating means when the operation of the brake operating member is not detected. Alternatively, instead of determining that the left and right wheel speed difference of the vehicle is less than a predetermined speed, a lateral acceleration detecting means for detecting a lateral acceleration of the vehicle is added, and the lateral acceleration detecting means detects the lateral acceleration. The static load estimating means may be allowed to estimate when the lateral acceleration of the vehicle is less than a predetermined acceleration.

[0019]

DETAILED DESCRIPTION OF THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows the overall configuration of a vehicle braking device including a braking force distribution control device according to an embodiment of the present invention. A hydraulic pressure generating device is used as the braking force generating device of the present invention, and a liquid pressure is used as the braking force control device. The pressure control means is used. The braking device according to the present embodiment is a brake by wire electronically controlled braking system, particularly an electronically controlled hydraulic braking system (Electr).
o-Hydraulic Brake System), but may be a conventional mechanical hydraulic brake system.

That is, the operation amount of the brake pedal BP is detected by the brake operation sensor BS, and the electronic control unit ECU controls the brake hydraulic pressure control device BC of the hydraulic pressure control means according to the detection result. ing. As the brake operation sensor BS, there is a stroke sensor that detects a stroke when the brake pedal BP is operated, a pedal force sensor that detects a pedal force, or the like.
If the master cylinder is provided, a hydraulic pressure sensor may be used. In addition, the brake fluid pressure control device BC
Is to control the brake fluid pressure supplied from the fluid pressure source PR by a plurality of electromagnetic on-off valves. For example, the control of the brake fluid pressure in the braking force distribution control is described in JP-A-8-108.
Since it is the same as the one described in Japanese Patent No. 841, the detailed description is omitted.

Wheel cylinders Wfr, Wfl, Wrr, Wrl are mounted on the wheels FR, FL, RR, RL, respectively, and a brake fluid pressure control device BC is connected to these wheel cylinders Wfr, etc. The wheel FL indicates the wheel on the front left side as viewed from the driver's seat, hereinafter the wheel FR indicates the front right side, the wheel RL indicates the rear left side, and the wheel RR indicates the rear right side wheel. Wheel speed sensors WS1 to WS4 are provided on the wheels FR, FL, RR, RL, and these are connected to an electronic control unit ECU, and the rotation speed of each wheel, that is, a pulse signal of a pulse number proportional to the wheel speed. Is input to the electronic control unit ECU. Further, a front wheel steering angle sensor SSf that detects a steering angle θh by a driver's steering operation, a longitudinal acceleration sensor XG that detects a longitudinal acceleration Gx of the vehicle, a lateral acceleration sensor YG that detects a lateral acceleration Gy of the vehicle, and a yaw rate γ of the vehicle. The yaw rate sensor YS for detecting the above, the above-mentioned brake operation sensor BS, and the like are connected to the electronic control unit ECU.

In the present embodiment configured as described above, the electronic control unit ECU performs a series of processes for the braking force distribution control, and the ignition switch (not shown) is closed. Then, the execution of the program corresponding to the flow charts of FIG. 2 and FIG. 3 is started,
The process is repeated in a predetermined cycle. 2 and 7 are performed in several tens of ms, the calculation processes in FIGS. 3 to 6 may be performed in 1 to 2 minutes, and thus it is preferable that these are interrupt processes.

In FIG. 2, first, initialization is performed in step 101, and the initial value of the static load of each wheel is set based on the vehicle weight and the like. Subsequently, in step 102, the signals from the respective sensors are input, and the flow proceeds to step 103, in which the wheel speed of each wheel (representatively represented by Vw) is calculated based on the output signals from the wheel speed sensors WS1 to WS4.
Then, in step 104, the μ gradient of each wheel is calculated based on the wheel speed Vw, and the static load of each wheel is set based on this μ gradient (this will be described later with reference to FIG. 3).

Next, at step 105, the above μ
From the static load of each wheel based on the gradient, the longitudinal acceleration Gx,
A dynamic load change amount is calculated based on the lateral acceleration Gy, the yaw rate γ, and the like. For example, the dynamic load of each wheel is calculated as follows based on the longitudinal acceleration Gx and the lateral acceleration Gy. W _DL1 = W _SL1 -K _GX / Gx / W _SUM + K _GY1 / Gy
W _SUM W _DR1 = W _SR1 -K _GX / Gx / W _SUM -K _GY1 / Gy /
W _SUM W _DL2 = W _SL2 + K _GX / Gx / W _SUM + K _GY2 / Gy /
W _SUM W _DR2 = W _SR2 + K _GX・ Gx ・ W _SUM −K _GY2・ Gy ・
W _SUM

Here, K _GX represents a constant based on the height of the center of gravity and the wheel base, and K _GY1 and K _GY2 are the height of the center of gravity,
It represents a constant based on the distribution of tread and roll rigidity. Further, W _SL1 is a static load on the left side of the front wheel, W _SR1 is a static load on the right side of the front wheel, W _SL2 is a static load on the left side of the rear wheel, and W _SR2 is a static load on the right side of the rear wheel. W _DL1 represents a dynamic load on the left side of the front wheel, W _DR1 represents a dynamic load on the right side of the front wheel, W _DL2 represents a dynamic load on the left side of the rear wheel, and W _DR2 represents a dynamic load on the right side of the rear wheel. W
_SUM is the above total value (W _SUM = W _SL1 + W _SR1 +
W _SL2 + W _SR2 ).

Then, the routine proceeds to step 106, where the target braking force of each wheel is calculated based on the above-mentioned dynamic load of each wheel and set to an optimum value. Thus, in step 107, the target braking force is applied to each wheel (for example,
The braking force is controlled (as described in JP 2001-287635 A). Since the braking force is proportional to the slip ratio of the wheels, the target braking force may be replaced with the target slip ratio, and the braking force control based on the slip ratio of the wheels may be performed.

An example of the static load estimation calculation in step 104 is shown in FIG. First, in step 201, the calculation permission condition is determined. Specifically, the calculation is allowed when all of the following conditions are satisfied. That is,
The conditions are (1) not being braked, (2) not being turned, and (3) being in a steady traveling state. Regarding the condition (1), it can be determined that braking is not being performed based on the detection result of the brake operation sensor BS (or when the stop switch is provided, when the stop switch is off). Regarding the condition (2), when the wheel speed difference between the left and right wheels is less than or equal to a predetermined value, or when any one of the steering angle θh, the lateral acceleration Gy, and the yaw rate γ is less than or equal to a predetermined value, the vehicle is not turning (straight ahead). (During traveling). Regarding the condition (3), the vehicle body acceleration (for example, the differential value DVso of the estimated vehicle body speed calculated based on the wheel speed Vw of each wheel) or the wheel acceleration (for example, the differential value DVw of the wheel speed Vw) is a predetermined value. In the following cases, it can be determined that the vehicle is in a steady traveling state (traveling at a substantially constant speed).

When the calculation is permitted in step 201, the process proceeds to step 202, and the wheel speed Vw of each wheel is calculated.
Based on, the μ gradient of each wheel is estimated. In particular, as described above, the braking stiffness can be represented by the gradient of the braking force Fk (that is, the static μ gradient) with respect to the wheel slip rate Sp near zero wheel slip rate shown in FIG. Regarding the estimation of the μ gradient of each wheel, for example, JP-A-11-078843 and JP-A 2001-18780.
The details are described in Japanese Laid-Open Patent Publication No. 2001-287635 and Japanese Laid-Open Patent Publication No. 2001-287635, and the description thereof will be omitted. Then, in step 203, the static load of each wheel is estimated based on the μ gradient of each wheel.

In the static load estimation calculation shown in FIG. 3, the static load is processed so as to be estimated at all times while the vehicle is running. It changes depending on loading and unloading. However, once these settings are made, static loads rarely fluctuate during traveling. Therefore, as a second example of the static load estimation calculation, as shown in FIG. 4, the process of step 301 may be added to the example of FIG. That is, it is determined in step 301 whether or not the calculation is necessary. For example, when the vehicle is stopped for a predetermined time or more, and / or when the door or trunk of the vehicle is opened or closed, the static load is applied. Is estimated. First, after the initial value of the static load is set in step 302, the process proceeds to steps 303 to 305 and is processed in the same manner as steps 201 to 203 in FIG.

Normally, the static load should be about the same for the left and right wheels. However, for example, when the left and right tire air pressures are different, or when one of the wheels is replaced with an emergency tire, The μ gradient changes. That is, even when there is a difference in the static load on the left and right wheels due to changes in tire air pressure or replacement with an emergency tire, the static load on each wheel may change due to changes in the carrying load and changes in occupants. Since the same estimation result as when it fluctuates is confused, it is desirable to add a measure to exclude such a case. In this case, as a third example of the static load estimation calculation, as shown in FIG. 5, the process of step 403 may be added to the first example shown in FIG. That is, step 40
After the μ gradient is calculated in step 2, step 4
In 03, the difference in the μ gradient between the left and right wheels (absolute value)
Is determined to be less than the predetermined value K1 only in step 40
Proceeding to 4, the static load is estimated. The processing of steps 401, 402 and 404 is the same as step 2 of FIG.
The same as 01 to 203.

As described above, when the tire pressures are different, the μ gradient changes. Therefore, as a fourth example of the static load estimation calculation, as shown in FIG. 6, the process of step 502 is added to the first example shown in FIG. 3 so that the tire pressure at each wheel is normal. It is also possible to estimate the static load only in the area.
That is, after the calculation is permitted in step 501,
Only when it is determined in step 502 that the tire air pressure of each wheel is normal (for example, within a predetermined pressure range), the routine proceeds to step 503, where the μ gradient estimation calculation is performed. The processing of steps 501, 503 and 504 is the same as steps 201 to 203 of FIG. Thus, in step 502, the estimation start determination means based on the tire pressure is configured.

In the above step 502, the tire air pressure of each wheel is estimated and it is judged whether or not the tire air pressure is normal. Various means for detecting the tire air pressure are known as follows. Therefore, the description is omitted.
For example, there is (a) Japanese Patent Laid-Open No. 2000-203222 for directly detecting the tire air pressure, and (b) specially for detecting a change in tire air pressure as a change in dynamic load radius based on a wheel speed signal. Kaihei 4-212
JP-A-5-133831 discloses that (c) a change in tire air pressure is detected as a change in tire spring constant to detect a wheel speed signal by frequency analysis. Further, Japanese Patent Application Laid-Open No. 9-2031 discloses a combination of the above (b) and (c).

Although FIG. 3 to FIG. 6 show four examples of the static load estimation calculation, two or more of these may be combined appropriately.

FIG. 7 shows another embodiment of the present invention. The processing of step 603 is added to the processing of the braking force distribution control shown in FIG. 2, and the signal of each sensor is input in step 602. After that, the vehicle target braking force is calculated. That is, in step 603, for example, a stroke sensor or a pedaling force sensor is arranged in the brake operating portion (for example, the brake pedal BP), and based on the detection signal, or when the master cylinder is provided, the master cylinder pressure sensor. The braking request of the driver is determined on the basis of the detection signal and the vehicle target braking force is calculated according to the braking request. Then, this vehicle target braking force is distributed to each wheel according to the estimated load value of each wheel obtained based on the static load and the dynamic load change. Incidentally, step 60
The processing of each step other than 3 is substantially the same as the processing of steps 101 to 107 in FIG.

[0035]

Since the present invention is configured as described above, it has the following effects. That is, the braking force distribution control device according to claim 1 estimates the static load of each wheel based on the braking stiffness when the vehicle is traveling straight at a substantially constant speed, and determines the static load of each wheel according to the estimation result. Since it is configured to control the braking force, it is not necessary to calculate the μ gradient in real time, and the braking force distribution control can be appropriately performed without the need for an expensive sensor or the like. Various devices can be configured.

According to the second aspect of the invention, the braking force distribution control device can be constructed by the hydraulic brake system. Alternatively, if configured as described in claim 3, the braking force distribution control device can be configured by an electronically controlled brake system.

According to the fourth aspect, the dynamic load is further estimated based on the static load of each wheel,
Since the braking force of each wheel is controlled according to the estimation result, the braking force distribution control can be more appropriately performed without calculating the μ gradient in real time.

Further, in each of the above braking force distribution control devices, as described in claim 5, the air pressure of the tire of the wheel in front of the vehicle is detected, and only when the air pressure is within a predetermined pressure range. Since it is configured to allow the estimation of the static load, it is possible to prevent the malfunction due to the fluctuation of the tire air pressure and perform the braking force distribution control more appropriately.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of a braking force distribution control device according to an embodiment of the present invention.

FIG. 2 is a flowchart showing a process of braking force distribution control in the embodiment of the present invention.

FIG. 3 is a flowchart showing a first example of a static load estimation calculation according to the embodiment of the present invention.

FIG. 4 is a flowchart showing a second example of a static load estimation calculation according to the embodiment of the present invention.

FIG. 5 is a flowchart showing a third example of the static load estimation calculation according to the embodiment of the present invention.

FIG. 6 is a flowchart showing a fourth example of static load estimation calculation according to an embodiment of the present invention.

FIG. 7 is a flowchart showing a process of braking force distribution control according to another embodiment of the present invention.

FIG. 8 is a graph showing a relationship between a wheel slip ratio and a braking force.

[Explanation of symbols]

BP brake pedal, BS brake operation sensor,
BC brake hydraulic pressure control device, ECU electronic control device XG longitudinal acceleration sensor, YG lateral acceleration sensor, Y
S Yaw rate sensor, WS1 to WS4 Wheel speed sensor, Wfr, Wfl, Wrr, Wrl Wheel cylinder, F
R, FL, RR, RL wheels

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Yoshiyuki Yasui             Aichi, 2-chome, Asahi-cho, Kariya city, Aichi prefecture             Within Seiki Co., Ltd. (72) Inventor Kenji Asano             Aichi, 2-chome, Asahi-cho, Kariya city, Aichi prefecture             Within Seiki Co., Ltd. (72) Inventor Eiichi Ono             Aichi Prefecture Nagachite Town Aichi District             Ground 1 Toyota Central Research Institute Co., Ltd. (72) Inventor Yoshitoshi Watanabe             Aichi Prefecture Nagachite Town Aichi District             Ground 1 Toyota Central Research Institute Co., Ltd. (72) Inventor Mineichi Moriyama             1-1 Asahi-cho, Kariya city, Aichi             Machine Co., Ltd. F term (reference) 3D046 BB21 BB23 CC02 HH02 HH25                       HH26 HH35 HH36 HH46 KK12                       LL05 LL17

Claims (5)

[Claims] 1. A braking force generating means for generating a braking force applied to each wheel of a vehicle, a wheel speed detecting means for detecting a speed of each wheel, and at least the output according to the output of the wheel speed detecting means. A braking force distribution control device for a vehicle, comprising: a braking force control unit that controls the output of a braking force generation unit to control the braking force of each wheel to adjust the braking force distribution between the wheels. Based on the braking stiffness calculation means for calculating the braking stiffness of each wheel based on the output of the speed detection means, and the calculation result of the braking stiffness calculation means when the vehicle is traveling straight at a substantially constant speed, each wheel And a static load estimating means for estimating the static load of, wherein the braking force control means,
A braking force distribution control device for a vehicle, which controls a braking force of each wheel according to an estimation result of the static load estimating means. 2. A wheel cylinder mounted on each wheel of a vehicle to apply a braking force, a hydraulic pressure generator for supplying a brake hydraulic pressure to each of the wheel cylinders, and the hydraulic pressure generator and the wheel cylinder. A hydraulic pressure control device interposed between the hydraulic pressure control device for controlling the brake hydraulic pressure of the wheel cylinder, a wheel speed detecting means for detecting the speed of each wheel, and at least the hydraulic pressure according to the output of the wheel speed detecting means. A braking force including a braking force control unit that drives a control device to control the brake fluid pressure supplied to the wheel cylinders to control the braking force of each wheel and adjust the braking force distribution between the wheels. In the distribution control device, the braking stiffness calculating means for calculating the braking stiffness of each wheel based on the output of the wheel speed detecting means, and the vehicle traveling straight at a substantially constant speed. A static load estimating means for estimating a static load of each of the wheels based on a calculation result of the braking stiffness calculating means during traveling, wherein the braking force control means has an estimation result of the static load estimating means. A braking force distribution control device for a vehicle, wherein the braking force of each wheel is controlled according to the above. 3. A braking force generating means for generating a braking force applied to each wheel of the vehicle, a wheel speed detecting means for detecting the speed of each wheel, and at least an output of the wheel speed detecting means and the output of the vehicle. Target braking force calculation means for calculating the target braking force of each wheel based on the target braking force, and the braking force of each wheel by controlling the output of the braking force generation means based on the calculation result of the target braking force calculation means. A braking force distribution control device for a vehicle, the braking force distribution control device including a braking force control means for controlling a braking force distribution between the wheels to calculate a braking stiffness of each wheel based on an output of the wheel speed detection means. And a static stiffness estimating means for estimating the static load of each wheel based on the calculation results of the braking stiffness calculating means and the braking stiffness calculating means while the vehicle is traveling straight at a substantially constant speed. And a dynamic load estimating means, wherein the braking force control means controls the braking force of each wheel according to the estimation result of the static load estimating means. 4. A longitudinal acceleration detecting means for detecting a longitudinal acceleration of the vehicle, a lateral acceleration detecting means for detecting a lateral acceleration of the vehicle, and detections of the lateral acceleration detecting means and the longitudinal acceleration detecting means. A dynamic load estimating means for calculating a dynamic load between the wheels based on a result and an estimation result of the static load estimating means, wherein the braking force control means, the estimated result of the dynamic load estimating means. The braking force of each of the wheels is controlled in accordance with the above.
Alternatively, the vehicle braking force distribution control device according to the third aspect. 5. A static pressure detecting means for detecting the air pressure of a tire of a wheel in front of the vehicle is provided, and the static pressure is provided only when the air pressure detected by the air pressure detecting means is within a predetermined pressure range. 2. An estimation start determination means for permitting the estimation of the load estimation means is provided.
2. A braking force distribution control device for a vehicle according to 2, 3, or 4.