JP2010284990A - Braking force control device of vehicle - Google Patents

Braking force control device of vehicle Download PDF

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JP2010284990A
JP2010284990A JP2009138174A JP2009138174A JP2010284990A JP 2010284990 A JP2010284990 A JP 2010284990A JP 2009138174 A JP2009138174 A JP 2009138174A JP 2009138174 A JP2009138174 A JP 2009138174A JP 2010284990 A JP2010284990 A JP 2010284990A
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braking force
vehicle
rear wheel
wheel
force distribution
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Hiroshi Obuchi
浩 大渕
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Toyota Motor Corp
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Toyota Motor Corp
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Abstract

<P>PROBLEM TO BE SOLVED: To allocate the braking force to rear and front wheels so as to effectively use the braking force in the rear wheels even in an optionally loaded state without having to determine whether the braking force in the rear wheels reaches an impregnation area with the low braking force in a braking force control device of a vehicle. <P>SOLUTION: In the vehicle, a ratio of allocating the braking force to front and rear wheels is set so that the braking force in the rear wheels reaches the braking force in the rear wheels by ideal braking force allocation to the front and rear wheels with light load when the braking force in the front wheels is larger than the predetermined value. When the braking force in the rear wheels reaches the braking force in the rear wheels by ideal braking force allocation to the front and rear wheels with light load, and the rear wheels are not in a slipped status, the allocation ratio of the braking force in the rear wheels is increased. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

本発明は、自動車等の車両の制動力制御装置に係り、より詳細には、乗車／積載状態が変化する車両の前後輪の制動力配分を制御する装置に係る。   The present invention relates to a braking force control device for a vehicle such as an automobile, and more particularly to a device for controlling the braking force distribution of front and rear wheels of a vehicle whose riding / loading state changes.

自動車等の車両の制動性能を考えるとき、良く知られているように、理想的には、車両の前輪及び後輪にて付与されるべき制動力は、車体に作用する慣性力による車両の後輪から前輪への荷重移動分を考慮した各輪タイヤの垂直荷重に比例するよう配分されることが好ましい（理想制動力配分−図４（Ａ）の点線又は一点鎖線）。各輪の発生可能なタイヤ力の限界は、各輪タイヤの垂直荷重に比例するので、上記の如き理想制動力配分によれば、原理的には、前輪及び後輪のいずれもがロックしない状態で車両に於いて最大の制動力を得ることが可能となる。一方、実際の前後輪の制動力の配分比は、制動系の機構、ホイールシリンダ径などにより一様に決まってしまうこと（図４の実直線）から、実際の制動力配分をそのまま理想制動力配分に整合させることはできない。そこで、実際の制動力配分（実制動力配分）は、通常、制動力又は減速度が低い間は、理想制動力配分の場合よりも前輪側の制動力の配分が大きくなるよう設定され（図中、実制動力配分線が理想制動力配分線よりも下側）、実制動力配分が理想制動力配分の場合よりも後輪側の制動力の配分が大きくなるとき（図中、白丸に於いて実制動力配分線が理想制動力配分線よりも上側になるとき）には、後輪制動力の増大を制限することにより、実際の制動力配分比ができるだけ理想制動力配分比に沿うように変化させられる。特に、乗車／積載状態が大きく変動し得る車両（特に、トラック、バスなど）の場合、各輪タイヤの垂直荷重に比例する理想制動力配分が、その車両の乗車／積載状態（車量総重量や重心位置）によって大きく異なることから（図４（Ａ）の点線と一点鎖線）、実制動力配分の場合の後輪側の制動力の配分が理想制動力配分の場合よりも大きくなるときが車両の乗車／積載状態によって変動する。そこで、乗車／積載状態が大きく変動し得る車両の制動系装置に於いては、ロード・センシング・プロポーショナル・バルブ（ＬＳＰＶ）や、ＥＢＤ（Electronic Brake force Distribution）制御などにより、実制動力配分比ができるだけ理想制動力配分比に沿うようにするための試みが為されている。   When considering the braking performance of a vehicle such as an automobile, as is well known, ideally, the braking force to be applied to the front and rear wheels of the vehicle is the rear of the vehicle due to the inertial force acting on the vehicle body. It is preferable that the load is distributed so as to be proportional to the vertical load of each wheel tire in consideration of the load movement from the wheel to the front wheel (ideal braking force distribution—dotted line or dashed line in FIG. 4A). Since the limit of the tire force that can be generated for each wheel is proportional to the vertical load of each wheel tire, according to the ideal braking force distribution as described above, in principle, neither the front wheel nor the rear wheel is locked. Thus, it becomes possible to obtain the maximum braking force in the vehicle. On the other hand, the actual braking force distribution ratio of the front and rear wheels is uniformly determined by the brake system mechanism, wheel cylinder diameter, etc. (solid line in FIG. 4). It cannot be aligned with the allocation. Therefore, the actual braking force distribution (actual braking force distribution) is normally set so that the distribution of the braking force on the front wheel side is larger than that of the ideal braking force distribution while the braking force or deceleration is low (see FIG. Medium, when the actual braking force distribution line is below the ideal braking force distribution line, and when the actual braking force distribution is greater than the ideal braking force distribution, the rear wheel braking force distribution is larger (indicated by white circles in the figure). When the actual braking force distribution line is above the ideal braking force distribution line), by limiting the increase in the rear wheel braking force, the actual braking force distribution ratio follows the ideal braking force distribution ratio as much as possible. To be changed. In particular, in the case of vehicles (especially trucks, buses, etc.) whose riding / loading conditions can fluctuate significantly, the ideal braking force distribution proportional to the vertical load of each wheel tire is determined by the vehicle's riding / loading conditions (total vehicle weight) And the center of gravity position) (the dotted line and the alternate long and short dash line in FIG. 4A), the distribution of braking force on the rear wheel side in the case of actual braking force distribution may be larger than in the case of ideal braking force distribution. It fluctuates depending on the riding / loading condition of the vehicle. Therefore, in a braking system for a vehicle in which the riding / loading state can fluctuate greatly, the actual braking force distribution ratio can be increased by load sensing proportional valve (LSPV) or EBD (Electronic Brake force Distribution) control. Attempts have been made to keep the ideal braking force distribution ratio as much as possible.

ＬＳＰＶは、端的に述べれば、流体圧式の制動系装置に於いて、ブレーキ圧が作動開始圧に達すると、後輪のブレーキ圧の増大を制限するよう構成された弁装置であって、かかる作動開始圧が車両の重量の変動に応じて変化する機構を有する弁装置である。かかるＬＳＰＶによれば、図４（Ｂ）に例示されている如く、車両の重量の増大と伴に後輪の制動力の増大の制限を開始する制動力の値（図中、白丸にて示された点）を増大することが可能となる。ＬＳＰＶの車両の重量の変動に応じて作動開始圧を変化する機構としては、例えば、車両のばね上とばね下との間に連結されたスプリングの撓みから得られる両者間の（車両の重量に対応する）寸法変化に応じて、作動開始圧が変化する機構が採用されている。一方、ＥＢＤ制御の場合は、前後輪の車輪速変化又はスリップ率の変化を参照し、それらの変化から後輪の制動力が飽和領域又は限界領域に達したと判定されると、後輪制動力の増大が制限される（図４（Ｃ）参照）。また、例えば、特許文献１では、車両の減速度が制御閾値を超えるとＥＢＤ制御を実行する制御方式に於いて、車両の減速度と実際に発生している制動力の大きさとから車両重量を推定し、車両重量が大きいほど、制御閾値を増大し、これにより、車両重量が大きいほど、後輪の制動力を増大できるようにすることが提案されている。   In short, the LSPV is a valve device configured to limit an increase in the brake pressure of the rear wheel when the brake pressure reaches the operation start pressure in the fluid pressure type braking system device. This is a valve device having a mechanism in which the starting pressure changes in accordance with a change in the weight of the vehicle. According to the LSPV, as illustrated in FIG. 4B, the braking force value (indicated by white circles in the figure) that starts limiting the increase in the braking force of the rear wheels as the vehicle weight increases. Increased). As a mechanism for changing the operation start pressure in accordance with the change in the weight of the vehicle of LSPV, for example, between the two obtained from the bending of a spring connected between the sprung and unsprung of the vehicle (the weight of the vehicle A mechanism is employed in which the actuation start pressure changes in response to dimensional changes. On the other hand, in the case of EBD control, reference is made to changes in the wheel speed or slip ratio of the front and rear wheels, and if it is determined from those changes that the braking force of the rear wheels has reached the saturation region or the limit region, The increase in power is limited (see FIG. 4C). Further, for example, in Patent Document 1, in a control system that executes EBD control when the vehicle deceleration exceeds a control threshold, the vehicle weight is calculated from the vehicle deceleration and the magnitude of the braking force actually generated. It has been estimated that the control threshold is increased as the vehicle weight increases, and thereby the braking force of the rear wheels can be increased as the vehicle weight increases.

特開平１１−１６５６２４JP-A-11-165624

上記の如きＬＳＰＶの場合、実際には、バルブを流通する流体の吸入抵抗や流体圧の調整が困難であり、また、スプリングの撓みから得られる寸法変化と車両の重量変化との関係が必ずしも線形性を有していないなどの理由で設計及び装着が困難である。   In the case of LSPV as described above, it is actually difficult to adjust the suction resistance and fluid pressure of the fluid flowing through the valve, and the relationship between the dimensional change obtained from the spring deflection and the vehicle weight change is not necessarily linear. It is difficult to design and install because it has no characteristics.

一方、後輪制動力の飽和領域の到達を判定して後輪制動力の制限を行うＥＢＤ制御に於いては、例えば、図４（Ｃ）の（ｉ）に例示されている如く、（勾配が一様な）実制動力配分線を、定積状態（最大積載時）での理想制動力配分線に沿うように設定すると、定積状態よりも軽い積載状態、例えば、軽積状態（無積載時）では、後輪制動力が前輪制動力よりも先に飽和領域に達する状態が、低い制動力又は減速度のとき（図中、白丸にて示された点のとき）、生じ得ることとなるので（実制動力配分線が理想制動力配分線より上側になると、後輪制動力が前輪制動力よりも先に飽和領域に達する）、制動力又は減速度が低い時に後輪制動力が飽和領域に達しているか否かを判定しなければならない場合が生ずる。しかしながら、制動力又は減速度が低い時、即ち、後輪のスリップ率又はスリップ量が小さい時に後輪制動力が飽和領域に達しているか否かを安定的に判定することは（Ｓ／Ｎ比が小さいなどの理由により）困難である。他方、ＥＢＤ制御に於いて、図４（Ｄ）の（ii）に例示されている如く、実制動力配分線を、軽積状態での理想制動力配分線に沿うように設定すると、後輪のスリップ率又はスリップ量が小さい時に後輪制動力が飽和領域に達しているか否かを判定する必要は低減されるが、軽積状態よりも重い積載状態に於いては、後輪制動力を有効に利用できないこととなる（後輪制動力に残される余裕が大きくなる。）。勿論、特許文献１の如く、車両総重量を検出し、検出された車両総重量に応じて実制動力配分線の勾配を変更することも原理的には可能であるが、車両総重量を別途検出するための手段が必要となる（理想制動力配分は、重心高によっても変動するので、実制動力配分の勾配を理想制動力配分の変化に的確に追従して変更することは処理が複雑であり困難となる。）。   On the other hand, in the EBD control in which the rear wheel braking force is limited by determining the arrival of the saturation region of the rear wheel braking force, for example, as illustrated in (i) of FIG. If the actual braking force distribution line is set to be along the ideal braking force distribution line in the fixed volume state (at maximum loading), a lighter loading state than the fixed volume state, for example, In the case of loading), the situation where the rear wheel braking force reaches the saturation region before the front wheel braking force is low braking force or deceleration (at the point indicated by a white circle in the figure). (If the actual braking force distribution line is above the ideal braking force distribution line, the rear wheel braking force reaches the saturation region before the front wheel braking force), the rear wheel braking force is low when the braking force or deceleration is low. There is a case in which it is necessary to determine whether or not a saturation region has been reached. However, when the braking force or deceleration is low, that is, when the rear wheel slip rate or slip amount is small, it is possible to stably determine whether or not the rear wheel braking force has reached the saturation region (S / N ratio). Is difficult). On the other hand, in the EBD control, if the actual braking force distribution line is set along the ideal braking force distribution line in the light load state as illustrated in (ii) of FIG. The necessity of determining whether the rear wheel braking force has reached the saturation region when the slip ratio or slip amount of the vehicle is small is reduced, but the rear wheel braking force is reduced in a heavy load state than a light load state. This means that it cannot be used effectively (the margin left for the rear wheel braking force increases). Of course, it is possible in principle to detect the total vehicle weight and change the gradient of the actual braking force distribution line in accordance with the detected total vehicle weight as in Patent Document 1, but the total vehicle weight is not included separately. (The ideal braking force distribution varies depending on the height of the center of gravity, so changing the gradient of the actual braking force distribution to accurately follow the change in the ideal braking force distribution is complicated.) It will be difficult.)

かくして、本発明の一つの課題は、制動力又は減速度が低い時に後輪制動力が飽和領域に達しているか否かの判定を行う必要なく、また、車両総重量等を別途検出する必要なく、且つ、軽積状態よりも重い積載状態に於いても後輪制動力を有効に利用できるように前後輪制動力配分を行う車両の制動力制御装置を提供することである。   Thus, one object of the present invention is that it is not necessary to determine whether or not the rear wheel braking force has reached the saturation region when the braking force or deceleration is low, and it is not necessary to separately detect the total vehicle weight or the like. Another object of the present invention is to provide a braking force control device for a vehicle that distributes the front and rear wheel braking force so that the rear wheel braking force can be used effectively even in a heavier load state than in a lightly loaded state.

本発明の一つの態様によれば、上記の課題は、車両の制動力制御装置であって、車両の前輪の制動力が所定の制動力値より大きいときに車両の後輪の制動力が車両の所定の積載状態での前後輪理想制動力配分に於ける後輪の制動力に到達するよう車両の前後輪制動力配分比が設定され、車両の後輪の制動力が車両の所定の積載状態での前後輪理想制動力配分に於ける後輪の制動力に到達したか否かを判定する第一の判定部と、車両の後輪のスリップ状態値が所定閾値を超えたか否かを判定する第二の判定部と、第一の判定部が後輪の制動力が車両の所定の積載状態での前後輪理想制動力配分に於ける後輪の制動力に到達したことを判定したときに第二の判定部が前記後輪のスリップ状態値が所定閾値を超えたと判定していないときには、車両の前輪の制動力に対する前記後輪の制動力の配分を増大する制動力配分制御部とが設けられていることを特徴とする装置によって達成される。   According to one aspect of the present invention, there is provided a braking force control device for a vehicle, wherein when the braking force of the front wheel of the vehicle is greater than a predetermined braking force value, the braking force of the rear wheel of the vehicle The vehicle front / rear wheel braking force distribution ratio is set so as to reach the rear wheel braking force distribution in the front / rear wheel ideal braking force distribution in a predetermined loading state. A first determination unit that determines whether or not the rear wheel braking force in the front and rear wheel ideal braking force distribution in the state has been reached, and whether or not the slip state value of the rear wheel of the vehicle has exceeded a predetermined threshold value The second determination unit and the first determination unit determine that the rear wheel braking force has reached the rear wheel braking force in the front and rear wheel ideal braking force distribution in a predetermined loading state of the vehicle. When the second determination unit does not determine that the slip state value of the rear wheel exceeds a predetermined threshold value, It is achieved by a device which is characterized in that the braking force distribution control unit to increase the proportion of the braking force of the rear wheel against the front wheel braking force is provided.

かかる本発明の一つの態様の装置の構成に於いて、車両の前後輪制動力配分比が、「車両の前輪の制動力が所定の制動力値より大きいときに車両の後輪の制動力が車両の所定の積載状態での前後輪理想制動力配分に於ける後輪の制動力に到達するよう」設定されるという構成は、要すれば、基本的には、車両の実前後輪制動力配分比が、車両の所定の積載状態での前後輪理想制動力配分の場合よりも前輪の制動力が大きくなる側に偏倚されている状態を意味している。「背景技術」の欄に於いて既に触れたように、通常、車両の実前後輪制動力配分比は、一様である。従って、前輪の制動力が所定の制動力値より小さいときには、後輪の制動力は、前後輪理想制動力配分の場合よりも低く設定されることとなり、前輪の制動力が所定の制動力値より大きくなったときに、初めて前後輪理想制動力配分の場合の後輪制動力の値に一致することとなる。また、第二の判定部に於いて参照される「後輪のスリップ状態値」とは、後輪制動力が飽和領域に達しているか否かを判定することのできる任意の状態値であってよく、例えば、後輪のスリップ率若しくはスリップ量、前輪車輪速と後輪車輪速との偏差値であってよい。更に、上記の「所定の制動力値」とは、車両又は制動系装置の設計者により任意に設定されてよいところ、典型的には且つ好適には、前輪の制動力が所定の制動力値となったときに、後輪制動力が飽和領域に達していることを安定的に若しくは精度よく判定することを可能にする程度の制動力値に設定される。   In the configuration of the apparatus according to one aspect of the present invention, the front-rear wheel braking force distribution ratio of the vehicle is “the braking force of the rear wheel of the vehicle is greater than the predetermined braking force value of the vehicle front wheel. The configuration of “reaching the braking force of the rear wheel in the ideal braking force distribution of the front and rear wheels in a predetermined loading state of the vehicle” is basically set to the actual front and rear wheel braking force of the vehicle. This means that the distribution ratio is biased to the side where the braking force of the front wheels becomes larger than in the case of the ideal braking force distribution of the front and rear wheels in a predetermined loading state of the vehicle. As already mentioned in the section “Background Art”, the actual front / rear wheel braking force distribution ratio of the vehicle is usually uniform. Accordingly, when the braking force of the front wheels is smaller than the predetermined braking force value, the braking force of the rear wheels is set lower than in the case of the front and rear wheel ideal braking force distribution, and the braking force of the front wheels is set to the predetermined braking force value. When it becomes larger, it will coincide with the value of the rear wheel braking force in the case of front and rear wheel ideal braking force distribution for the first time. The “rear wheel slip state value” referred to in the second determination unit is an arbitrary state value that can determine whether or not the rear wheel braking force has reached the saturation region. For example, it may be a slip ratio or slip amount of the rear wheel, or a deviation value between the front wheel speed and the rear wheel speed. Further, the above-mentioned “predetermined braking force value” may be arbitrarily set by a vehicle or braking system designer. Typically and preferably, the braking force of the front wheels is a predetermined braking force value. Then, the braking force value is set to such an extent that it can be determined stably or accurately that the rear wheel braking force has reached the saturation region.

かくして、上記の本発明の装置の構成によれば、車両の前輪の制動力が所定の制動力値に到達するまでは、後輪制動力は、前後輪理想制動力配分の場合に与えられる制動力値よりも下回ることとなり、その間、後輪制動力が飽和領域に達しているか否かの判定を行う必要性が低減される（路面の摩擦係数が低い場合には、先ず、前輪制動力が先に飽和する。その場合には、ＡＢＳ制御等が作動されて前輪のロック状態が回避され、また、運転者は、後輪がロックする前に車両に付与される制動力が限界に近いことを知ることができる。）。そして、前輪の制動力が所定の制動力値に到達し、後輪制動力が所定の積載状態での前後輪理想制動力配分に於ける後輪の制動力に到達したときに、まだ、後輪のスリップ状態値が所定閾値を超えたと判定されていなければ、即ち、後輪制動力が飽和領域に到達せず、余裕があるときには、後輪制動力の配分が増大され、これにより、後輪制動力を有効に利用することが可能となる。   Thus, according to the configuration of the device of the present invention, the rear wheel braking force is controlled in the case of the front and rear wheel ideal braking force distribution until the braking force of the front wheel of the vehicle reaches a predetermined braking force value. In the meantime, the necessity of determining whether or not the rear wheel braking force has reached the saturation region is reduced (when the road surface friction coefficient is low, first the front wheel braking force is reduced). In this case, ABS control or the like is activated to prevent the front wheels from being locked, and the driver must have a braking force applied to the vehicle before the rear wheels are locked. Can know.) When the braking force of the front wheel reaches a predetermined braking force value and the rear wheel braking force reaches the braking force of the rear wheel in the front and rear wheel ideal braking force distribution in a predetermined loading state, If it is not determined that the wheel slip state value exceeds the predetermined threshold value, that is, if the rear wheel braking force does not reach the saturation region and there is a margin, the distribution of the rear wheel braking force is increased. It is possible to effectively use the wheel braking force.

上記の構成に於いて、前後輪理想制動力配分を与える「所定の積載状態」としては、車両又は制動系装置の設計者により任意に想定されてよいところ、後輪のスリップ状態値が所定閾値を超えたことの判定が、制動力又は減速度ができるだけ高くなるまで待って行われるようにするためには、好適には、「軽積状態」、即ち、乗員が１〜２名乗車し荷台が空積となっている状態（厳密には、適用される法規によって異なる）が選択される。従って、その場合、図４に例示されている如き車両の実制動力配分線は、制動力又は減速度が低い領域に於いては、軽積時の理想制動力配分線よりも前輪側に沿って変位し、理想制動力配分線と交差したときに、後輪にスリップ傾向がなければ（後輪のスリップ状態値が所定の閾値を越えていなければ）、後輪制動力の配分がそれまでよりも増大されることとなる（図２参照）。   In the above configuration, the “predetermined loading state” that gives the ideal braking force distribution for the front and rear wheels may be arbitrarily assumed by the vehicle or braking system designer, but the slip state value of the rear wheel is a predetermined threshold value. In order to wait until the braking force or deceleration becomes as high as possible, it is preferable that the “light load state”, that is, one or two passengers get on the loading platform. Is selected (strictly speaking, it depends on the applicable law). Therefore, in this case, the actual braking force distribution line of the vehicle as illustrated in FIG. 4 is closer to the front wheel side than the ideal braking force distribution line at the time of light loading in a region where the braking force or deceleration is low. If the rear wheel does not tend to slip when the ideal braking force distribution line intersects (if the rear wheel slip state value does not exceed the predetermined threshold), the rear wheel braking force distribution is (See FIG. 2).

なお、既に触れたように、一般に、（特に各輪独立に制動力を調節する制御が実行されていない場合には、）実前後輪制動力配分比は一様、即ち、所定の比に固定されており、本発明の装置では、実前後輪制動力配分比が、所定の積載状態（好適には、軽積状態）の理想制動力配分に一致したときに後輪制動力に余裕がある場合に、制動力配分制御部によって後輪制動力の配分比が増大されることとなる。従って、上記の実施の態様に於いては、制動力配分制御部による後輪の制動力の配分の増大が実行された後の車両の前輪の制動力に対する後輪の制動力の変化勾配は、制動力配分制御部による前記後輪の制動力の配分の増大が実行される前の車両の前輪の制動力に対する後輪の制動力の変化勾配よりも大きくなるよう構成されていてよい。   As already mentioned, in general, the actual front / rear wheel braking force distribution ratio is uniform, that is, fixed to a predetermined ratio (especially when control for adjusting the braking force is not performed independently for each wheel). In the apparatus of the present invention, the rear wheel braking force has a margin when the actual front and rear wheel braking force distribution ratio matches the ideal braking force distribution in a predetermined loading state (preferably, a lightly loaded state). In this case, the distribution ratio of the rear wheel braking force is increased by the braking force distribution control unit. Therefore, in the above-described embodiment, the change gradient of the braking force of the rear wheel with respect to the braking force of the front wheel of the vehicle after the increase of the distribution of the braking force of the rear wheel by the braking force distribution control unit is executed, The braking force distribution control unit may be configured to be larger than the change gradient of the braking force of the rear wheel with respect to the braking force of the front wheel of the vehicle before the increase in the distribution of the braking force of the rear wheel is executed.

また、上記の構成に於いて、第二の判定部が後輪のスリップ状態値が所定閾値を超えたと判定したとき、即ち、後輪のスリップ傾向が検出されたときには、制動力配分制御部が後輪の制動力の増大を制限するよう構成され、これにより、後輪のロックが回避されるようになっていてよい。   In the above configuration, when the second determination unit determines that the rear wheel slip state value exceeds a predetermined threshold value, that is, when a rear wheel slip tendency is detected, the braking force distribution control unit The rear wheel may be configured to limit an increase in braking force, thereby preventing the rear wheel from being locked.

ところで、上記の本発明は、要すれば、車両の前後輪制動力配分が、初めは、軽積時の前後輪理想制動力配分比よりも前輪側に偏倚させ、後輪の制動力の増大を緩やかに設定しておき、前後輪制動力配分が軽積時の前後輪理想制動力配分に到達したときに、後輪制動力に余裕があれば、後輪制動力の配分をそれまでよりも増大して、後輪制動力を有効に使えるようにするというものである。従って、本発明のもう一つの態様に於いて、本発明の装置は、車両の前輪の制動力が所定の制動力値より小さいときには前後輪の制動力配分比が車両の軽積時の前後輪理想制動力配分比よりも前輪側に偏っており、車両の前輪の制動力が所定の制動力値に到達したときに車両の後輪制動力が飽和領域に達していない場合には、前後輪の制動力配分比が後輪側に増大されるよう前後輪の制動力配分を実行するよう構成されていてよい。また、車両の制動系装置が、流体圧式制動装置（空気圧・油圧式制動装置、空気圧式制動装置、油圧式制動装置など）である場合、本発明の制動力制御装置は、車両の前輪及び後輪のブレーキ圧が所定の圧力値より小さいときには前後輪の制動力配分比が車両の軽積時の前後輪理想制動力配分比よりも前輪側に偏っており、前後輪の制動力配分比が車両の軽積時の前後輪理想制動力配分比に到達したときに車両の後輪制動力が飽和領域に達していない場合には、前後輪の制動力配分比がそれまでよりも後輪側に偏倚されるよう前後輪の制動力配分を実行するよう構成されていてよい。これらの構成に於いても、制動力又は減速度が低いときには、後輪制動力が飽和領域に達しているか否かの判定を行う必要性が低減される一方、後輪制動力に余裕があるときには、その後輪制動力を有効に利用できるようにすることができることとなる。   By the way, according to the present invention, if necessary, the front and rear wheel braking force distribution of the vehicle is initially biased to the front wheel side with respect to the front and rear wheel ideal braking force distribution ratio at the time of light loading, thereby increasing the rear wheel braking force. If the rear wheel braking force distribution reaches the front and rear wheel ideal braking force distribution at the time of light loading and the rear wheel braking force has a margin, the rear wheel braking force distribution will be distributed more than before. In this way, the rear wheel braking force can be used effectively. Therefore, in another aspect of the present invention, the device of the present invention is configured so that when the braking force of the front wheels of the vehicle is smaller than a predetermined braking force value, the braking force distribution ratio of the front and rear wheels is low when the vehicle is lightly loaded. If the rear wheel braking force of the vehicle has not reached the saturation region when the braking force of the front wheel of the vehicle has reached a predetermined braking force value, the front and rear wheels The braking force distribution of the front and rear wheels may be executed so that the braking force distribution ratio of the rear wheel is increased to the rear wheel side. Further, when the vehicle braking system device is a fluid pressure type braking device (pneumatic / hydraulic braking device, pneumatic braking device, hydraulic braking device, etc.), the braking force control device of the present invention includes a front wheel and a rear wheel of the vehicle. When the wheel brake pressure is smaller than the predetermined pressure value, the braking force distribution ratio of the front and rear wheels is biased to the front wheel side relative to the ideal braking force distribution ratio of the front and rear wheels when the vehicle is lightly loaded. If the rear wheel braking force of the vehicle does not reach the saturation region when the ideal braking force distribution ratio of the front and rear wheels when the vehicle is lightly loaded, the braking force distribution ratio of the front and rear wheels is closer to the rear wheel than before. The brake force distribution of the front and rear wheels may be executed so as to be biased by the vehicle. Even in these configurations, when the braking force or deceleration is low, the necessity for determining whether or not the rear wheel braking force has reached the saturation region is reduced, while the rear wheel braking force has a margin. Sometimes, the rear wheel braking force can be used effectively.

上記の本発明の装置の作用効果として理解されるべきことの一つは、車両の乗車／積載状態が大きく変動する車両に於いて、車両の重量や重心高を直接的に又は間接的に検出することなく、適切な制動力配分を実行することが可能となるということである。「背景技術」の欄及び図４の説明から理解される如く、車両の乗車／積載状態が大きく変動する車両に於いて、車両の積載量が増大するほど、後輪の垂直荷重が増大し、後輪制動力の限界が大きくなり、また、重心高が高くなるほど、後輪の動的な垂直荷重が低減し、後輪制動力の限界が小さくなるといった現象が生ずる。従って、従前の装置の幾つかに於いては、制動力配分を車両の重量に応じて変更することによりできるだけ制動性能を向上する試みが為されてきた。しかしながら、本発明の装置では、予め設定される実制動力配分を、後輪制動力が限界に達しているか否かの判定をできるだけ遅らせられるように調整すると伴に、後輪制動力が限界に達していない場合には、実制動力配分を後輪よりに偏倚する手法を採用し、これにより、車両の重量や重心高を検出せずに前後輪制動力配分を変更して、前後輪の制動力をできるだけ有効に利用することが可能となる。かかる本発明の構成によれば、車両の乗車／積載状態が変動しても制動力配分が的確なものとすることができ、特に、積載状態にある車両に於いては、後輪の制動力が増大されることとなるので、運転者による制動操作力が比較的低くても高い制動力が得られることとなり、制動操作が容易となることが期待される。   One of the things to be understood as the operational effect of the above-described device of the present invention is that the vehicle weight and the height of the center of gravity are detected directly or indirectly in a vehicle in which the riding / loading state of the vehicle varies greatly. This means that it is possible to execute appropriate braking force distribution without doing so. As understood from the column “Background Art” and the description of FIG. 4, in a vehicle in which the riding / loading state of the vehicle greatly fluctuates, the vertical load on the rear wheel increases as the loading amount of the vehicle increases. As the limit of the rear wheel braking force is increased and the height of the center of gravity is increased, the dynamic vertical load of the rear wheel is reduced, and the phenomenon that the limit of the rear wheel braking force is reduced occurs. Therefore, in some of the conventional apparatuses, attempts have been made to improve the braking performance as much as possible by changing the braking force distribution according to the weight of the vehicle. However, in the device according to the present invention, the actual braking force distribution set in advance is adjusted so that the determination as to whether or not the rear wheel braking force has reached the limit is delayed as much as possible, and the rear wheel braking force becomes the limit. If not, the method of biasing the actual braking force distribution to the rear wheels is adopted, and this allows the front and rear wheel braking force distribution to be changed without detecting the vehicle weight or the center of gravity height. The braking force can be used as effectively as possible. According to such a configuration of the present invention, the braking force distribution can be made accurate even when the riding / loading state of the vehicle fluctuates. In particular, in the vehicle in the loaded state, the braking force of the rear wheel Therefore, even if the braking operation force by the driver is relatively low, a high braking force can be obtained, and it is expected that the braking operation becomes easy.

本発明のその他の目的及び利点は、以下の本発明の好ましい実施形態の説明により明らかになるであろう。   Other objects and advantages of the present invention will become apparent from the following description of preferred embodiments of the present invention.

図１（Ａ）は、本発明の好ましい実施形態である制動力制御装置が搭載される車両の模式図である。図１（Ｂ）は、車両の制動系装置の構成を模式的に表した図である。図１（Ｃ）は、本発明の好ましい実施形態である制動力制御装置をブロック図の形式で表したものである。FIG. 1A is a schematic diagram of a vehicle on which a braking force control apparatus that is a preferred embodiment of the present invention is mounted. FIG. 1B is a diagram schematically showing the configuration of the vehicle braking system. FIG. 1C shows a braking force control apparatus according to a preferred embodiment of the present invention in the form of a block diagram. 図２は、本発明の制動力制御装置により与えられる前後輪の制動力の関係を表す図である。図中、点線が、車両が軽積状態にあるときの理想制動力配分線であり、一点鎖線が、車両が定積状態にあるときの理想制動力配分線であり、実太線が実制動力配分線を示している。白丸の状態で後輪にスリップ傾向がなければ、矢印に示されている如く、後輪の制動力（ブレーキ圧）が、実細線にて示された通常の配分比の場合よりも増大される。FIG. 2 is a diagram showing the relationship between the braking forces of the front and rear wheels provided by the braking force control device of the present invention. In the figure, the dotted line is the ideal braking force distribution line when the vehicle is in a lightly loaded state, the alternate long and short dash line is the ideal braking force distribution line when the vehicle is in a fixed volume state, and the solid thick line is the actual braking force The distribution line is shown. If there is no slip tendency in the rear wheels in the white circle state, the braking force (brake pressure) of the rear wheels is increased as compared with the normal distribution ratio indicated by the solid line, as shown by the arrows. . 図３は、本発明の車両の制動力制御装置（制動力配分制御部）の処理の流れをフローチャートの形式で表したものである。FIG. 3 is a flowchart showing the processing flow of the vehicle braking force control apparatus (braking force distribution control unit) according to the present invention. 図４は、従来の技術に於ける車両の前後輪の制動力の関係を表す図である。（Ａ）に於いて、点線が、車両が軽積状態にあるときの理想制動力配分線であり、一点鎖線が、車両が定積状態にあるときの理想制動力配分線であり、実太線が一般的な実制動力配分線であり、白丸の状態で後輪の制動力の増大の制限が実行される。（Ｂ）に於いて、ＬＳＰＶが組み込まれた制動系装置が搭載された車両に於ける軽積状態（点線）、定積状態の４０％及び７０％の積載状態、定積状態に於ける理想制動力配分線（一点鎖線）と実制動力配分線（実線）を示しており、それぞれの積載状態のとき、対応する白丸の状態になったときに後輪の制動力の増大の制限が実行されることが示されている。（Ｃ）は、ＥＢＤ制御が実行される車両に於ける実前後輪制動力配分線（実線（ｉ））が、定積状態に於ける理想制動力配分線（一点鎖線）に沿うように設定された場合を示しており、白丸は、車両が軽積状態のときにＥＢＤ制御が実行される状態を示している（ＥＢＤ制御実行後、実細線の如く、後輪制動力の増大が抑制される。）。（Ｄ）は、ＥＢＤ制御が実行される車両に於ける実前後輪制動力配分線（実線（ｉｉ））が、軽積状態に於ける理想制動力配分線（点線）に沿うように設定された場合を示している。FIG. 4 is a diagram illustrating the relationship between the braking forces of the front and rear wheels of the vehicle in the prior art. In (A), the dotted line is an ideal braking force distribution line when the vehicle is in a lightly loaded state, and the alternate long and short dash line is an ideal braking force distribution line when the vehicle is in a fixed volume state. Is a general actual braking force distribution line, and the increase in the braking force of the rear wheels is limited in a white circle state. In (B), in a light load state (dotted line), a 40% and 70% load state in a vehicle equipped with a braking system incorporating the LSPV, an ideal in a constant volume state The braking force distribution line (one-dot chain line) and the actual braking force distribution line (solid line) are shown. In each loaded state, the increase in the braking force of the rear wheel is limited when the corresponding white circle is reached. Has been shown to be. (C) is set so that the actual front / rear wheel braking force distribution line (solid line (i)) in the vehicle on which the EBD control is executed follows the ideal braking force distribution line (one-dot chain line) in the fixed volume state. The white circles indicate a state in which EBD control is executed when the vehicle is in a lightly loaded state (after execution of EBD control, increase in rear wheel braking force is suppressed as indicated by a solid line). ) (D) is set so that the actual front and rear wheel braking force distribution line (solid line (ii)) in the vehicle on which the EBD control is executed follows the ideal braking force distribution line (dotted line) in the light load state. Shows the case.

以下に添付の図を参照しつつ、本発明を幾つかの好ましい実施形態について詳細に説明する。図中、同一の符号は、同一の部位を示す。   The present invention will now be described in detail with reference to a few preferred embodiments with reference to the accompanying drawings. In the figure, the same reference numerals indicate the same parts.

装置の構成
図１（Ａ）は、自動車等の車両の前後輪の制動力の配分を制御する本発明による車両の制動力制御装置の好ましい実施形態が搭載される車両１０を概略的に示している。車両１０は、公知の任意の形式の車両であってよく、一対の前輪１２ｆ及び一対の後輪１２ｒと、任意の積載物Ｓが載置される荷台１４とを有している。なお、図示の例では、簡単のため、車両後方部に上部が開放された荷台を有するトラックとして描かれているが、本発明の装置の搭載される車両は、箱型荷台を後方に有するトラック、前方にも荷台を有する車両、バス、その他の任意の積載物が積載可能な車両であってよい。 Configuration of Device FIG. 1 (A), shows a vehicle 10 in which the preferred embodiment of the braking force control apparatus for a vehicle according to the present invention for controlling the distribution of braking forces of front and rear wheels of a vehicle such as an automobile is mounted schematically Yes. The vehicle 10 may be any known type of vehicle, and includes a pair of front wheels 12f and a pair of rear wheels 12r, and a loading platform 14 on which an arbitrary load S is placed. In the illustrated example, for the sake of simplicity, it is depicted as a truck having a loading platform whose upper part is opened at the rear of the vehicle. However, a vehicle on which the apparatus of the present invention is mounted has a truck having a box-shaped loading platform at the rear. In addition, the vehicle may be a vehicle having a loading platform in front, a bus, and other vehicles capable of being loaded.

車両１０の前輪及び後輪の制動は、図１（Ｂ）に模式的に示されている如き通常の態様の制動系装置４０により行われる。端的に述べれば、制動系装置４０は、所謂電子制御式の空気・油圧式制動装置、空気圧式制動装置又は油圧式制動装置であってよく、運転者によるブレーキペダル４４の踏込みに応答して作動されるブレーキバルブ（又はマスタシリンダ）４５に連通した流体圧回路（空気圧回路及び／又は油圧回路）４６によって、各輪に装備をされたホイールシリンダ４２ｉ（ｉ＝fl、fr、rl、rr 以下同様。）内のブレーキ圧、即ち、各輪に於ける制動力、が調節される。流体圧回路４６には、通常の態様にて、各輪のホイールシリンダを、選択的に、エアコンプレッサ、エアタンク、制動力倍力装置、オイルポンプ、オイルリザーバ等（図示せず）へ連通する種々の弁（モジュレータ、流体圧保持弁、減圧弁等）が設けられており、通常の作動に於いては、ブレーキペダル４４の踏込みに対応した大きさの制動倍力装置、エアタンク又はマスタシリンダの圧力（以下、マスタブレーキ圧Ｐｂとする。）が等圧にてそれぞれのホイールシリンダ４２ｉへ供給される。しかしながら、本発明による制動力配分制御、ＡＢＳ制御、その他の任意の運動制御を実行するべく、各輪の制動力を個別に又は独立に調節する場合には、電子制御装置５０の指令に基づいて、前記の種々の弁が作動され、各輪のホイールシリンダ内のブレーキ圧が、対応する圧力センサの検出値に基づいて、それぞれの目標圧に合致するよう制御される。電子制御装置５０は、通常の形式の、双方向コモン・バスにより相互に連結されたＣＰＵ、ＲＯＭ、ＲＡＭ及び入出力ポート装置を有するマイクロコンピュータ及び駆動回路を含んでいてよく、ブレーキペダル４４に設けられた踏込量センサ（図示せず）からのブレーキペダル踏込量θｂ、各輪に設けられた車輪速センサ（図示せず）からの車輪速度Ｖｗｉ、ホイールシリンダ圧力センサからの各輪のホイールシリンダ内の圧力Ｐｂｉ等の検出値が入力される（図示されているものの他、前後加減速度、横加速度、ヨーレート等の本実施形態の車両に於いて実行されるべき各種制御に必要な種々のパラメータの値を表す各種検出信号が入力されてよい。）。   The braking of the front wheels and the rear wheels of the vehicle 10 is performed by a braking system device 40 in a normal mode as schematically shown in FIG. In short, the braking system device 40 may be a so-called electronically controlled pneumatic / hydraulic braking device, pneumatic braking device, or hydraulic braking device, and operates in response to the depression of the brake pedal 44 by the driver. Wheel cylinders 42i (i = fl, fr, rl, rr, etc.) equipped to each wheel by a fluid pressure circuit (pneumatic circuit and / or hydraulic circuit) 46 communicating with a brake valve (or master cylinder) 45 to be operated .)), Ie the braking force on each wheel. In the fluid pressure circuit 46, various types of wheel cylinders for each wheel selectively communicate with an air compressor, an air tank, a braking force booster, an oil pump, an oil reservoir, etc. (not shown) in a normal manner. In the normal operation, the pressure of the brake booster, the air tank or the master cylinder of the size corresponding to the depression of the brake pedal 44 is provided. (Hereinafter, referred to as master brake pressure Pb) is supplied to each wheel cylinder 42i at equal pressure. However, in the case where the braking force of each wheel is adjusted individually or independently in order to execute the braking force distribution control, the ABS control, or any other motion control according to the present invention, it is based on the command of the electronic control unit 50. The various valves are operated, and the brake pressure in the wheel cylinder of each wheel is controlled to match the target pressure based on the detection value of the corresponding pressure sensor. The electronic control unit 50 may include a microcomputer having a CPU, a ROM, a RAM, and an input / output port unit connected to each other by a bidirectional common bus and a driving circuit. Brake pedal depression amount θb from a given depression amount sensor (not shown), wheel speed Vwi from a wheel speed sensor (not shown) provided for each wheel, and in the wheel cylinder of each wheel from a wheel cylinder pressure sensor The detected values such as the pressure Pbi of the vehicle are input (in addition to those shown in the drawing, various parameters necessary for various controls to be executed in the vehicle of this embodiment, such as longitudinal acceleration / deceleration, lateral acceleration, yaw rate, etc. Various detection signals representing values may be input.)

なお、上記の制動系装置４０に於いて、通常時の実際の前後輪制動力の配分比（実制動力配分比）、即ち、各輪の制動力を個別に又は独立に制御しないとき（ＡＢＳ制御やＶＳＣ等のその他の運動制御が実行されていないとき）の前後輪制動力の配分比は、軽積状態（荷台が空積の状態）に於ける理想制動力配分比よりも前輪側に偏っているように設定される。換言すると、前輪制動力に対する後輪制動力の変化勾配は、軽積状態に於ける理想制動力配分の場合の勾配よりも低く設定され、前輪制動力が所定の値に到達するときに、実制動力配分比が軽積状態に於ける理想制動力配分比に一致するよう設定される（図２参照）。実制動力配分比が軽積状態に於ける理想制動力配分比に一致するときの前輪制動力の値（所定の値）は、そのときの後輪に於いてスリップ傾向があるか否かの判定、即ち、後輪制動力が飽和領域に達しているか否かの判定が安定的に為されるよう設定される。この点に関し、既に触れた如く、上記の制動系装置４０の場合、通常時、各輪のホイールシリンダへは、ブレーキペダルの踏込量に対応したマスタブレーキ圧Ｐｂが供給され、各輪の制動力が増減される。従って、各輪のホイールシリンダに於いては、前後輪に等圧のマスタブレーキ圧Ｐｂが供給されるとき、常に、（前輪制動力）＞（後輪制動力）の条件が成立するよう調整され、且つ、マスタブレーキ圧Ｐｂが所定圧Ｐｔｈに到達したときに、実制動力配分比が軽積状態に於ける理想制動力配分比に一致するよう設定される。好適には、軽積状態の理想制動力配分に於いて、前輪制動力の変化量に対する後輪制動力の変化量が微小となる状態のとき（所定量より小さくなるとき）に、マスタブレーキ圧Ｐｂが所定圧Ｐｔｈに到達するように、即ち、実制動力配分比が軽積状態の理想制動力配分比に一致するように前後輪のブレーキ係数（＝制動力／ホイールシリンダ圧）の関係が調整される。   In the braking system 40 described above, when the actual front / rear wheel braking force distribution ratio (actual braking force distribution ratio) in normal times, that is, when the braking force of each wheel is not controlled individually or independently (ABS The distribution ratio of the front and rear wheel braking force (when control and other motion control such as VSC are not executed) is closer to the front wheel than the ideal braking force distribution ratio in the light load state (the load platform is empty). It is set to be biased. In other words, the change gradient of the rear wheel braking force relative to the front wheel braking force is set lower than the gradient in the case of the ideal braking force distribution in the light load state, and when the front wheel braking force reaches a predetermined value, The braking force distribution ratio is set to coincide with the ideal braking force distribution ratio in the light load state (see FIG. 2). The value (predetermined value) of the front wheel braking force when the actual braking force distribution ratio matches the ideal braking force distribution ratio in the light load state is whether or not there is a slip tendency at the rear wheel at that time. It is set so that the determination, that is, the determination of whether or not the rear wheel braking force has reached the saturation region, is made stably. In this regard, as already mentioned, in the case of the braking system device 40 described above, the master brake pressure Pb corresponding to the depression amount of the brake pedal is normally supplied to the wheel cylinders of the wheels, so that the braking force of the wheels is increased. Is increased or decreased. Therefore, the wheel cylinders of the respective wheels are adjusted so that the condition of (front wheel braking force)> (rear wheel braking force) is always satisfied when the equal master brake pressure Pb is supplied to the front and rear wheels. In addition, when the master brake pressure Pb reaches the predetermined pressure Pth, the actual braking force distribution ratio is set to coincide with the ideal braking force distribution ratio in the lightly loaded state. Preferably, in the ideal braking force distribution in the light load state, when the change amount of the rear wheel braking force with respect to the change amount of the front wheel braking force is small (when smaller than a predetermined amount), the master brake pressure The relationship between the front and rear wheel brake coefficients (= braking force / wheel cylinder pressure) is such that Pb reaches a predetermined pressure Pth, that is, the actual braking force distribution ratio matches the ideal braking force distribution ratio in the light load state. Adjusted.

電子制御装置５０に組み込まれる本発明の車両の制動力制御装置は、図１（Ｃ）のブロック図に例示されている如く、後輪のスリップ状態を判定するための後輪スリップ判定部５０ａ（第二の判定部）と、ブレーキ圧が前記の所定圧Ｐｔｈに達しているか否かを判定するブレーキ圧判定部５０ｂ（第一の判定部）と、前後輪の制動力配分を変更する制動力配分制御部５０ｃとを含んでいる。後輪スリップ判定部５０ａは、車輪速Ｖｗｉから任意の方法で決定される車速Ｖと後輪の車輪速Ｖｗｉ自体とに基づいて、後輪のスリップ状態値、例えば、スリップ率（＝（Ｖ−Ｖｗｒ）／Ｖ）、スリップ量（＝Ｖ−Ｖｗｒ）又は前後輪車輪速差（＝Ｖｗｆ−Ｖｗｒ）、が所定の閾値を超えたか否かを判定し、スリップ状態値が所定の閾値を超えたときには、後輪がスリップ傾向にある、即ち、後輪制動力が飽和領域に到達していると判定する。ブレーキ圧判定部５０ｂは、マスタブレーキ圧Ｐｂを参照して、それが所定圧Ｐｔｈに到達しているか否かを判定し、マスタブレーキ圧Ｐｂが所定圧Ｐｔｈに到達したと判定されたときには、前輪制動力が前記の所定値に到達し、実制動力配分比が軽積状態の理想制動力配分比に一致した状態となったことが判定されたこととなる（マスタブレーキ圧Ｐｂが所定圧Ｐｔｈに到達したことに代えて、ブレーキペダルの踏込量θｂが所定量に到達したことを判定するようになっていてもよい。）。制動力配分制御部５０ｃは、後輪スリップ判定部５０ａとブレーキ圧判定部５０ｂの判定に基づいて、後に詳細に述べる態様にて、前後輪のホイールシリンダへ供給するブレーキ圧を制御するべく流体圧回路の弁等の構成要素を制御する。なお、図１（Ｃ）の構成は、電子制御装置５０に於けるメモリ装置に予め記憶されたプログラムに従ったＣＰＵ及びその他の構成要素の処理作動により実現されることは理解されるべきである。   As illustrated in the block diagram of FIG. 1C, the vehicle braking force control device of the present invention incorporated in the electronic control device 50 is a rear wheel slip determination unit 50a (for determining the slip state of the rear wheels. A second determination unit), a brake pressure determination unit 50b (first determination unit) that determines whether or not the brake pressure has reached the predetermined pressure Pth, and a braking force that changes the braking force distribution of the front and rear wheels. Distribution control unit 50c. The rear wheel slip determination unit 50a is based on the vehicle speed V determined by an arbitrary method from the wheel speed Vwi and the rear wheel speed Vwi itself, for example, a slip state value of the rear wheel, for example, a slip ratio (= (V− Vwr) / V), slip amount (= V-Vwr) or front / rear wheel speed difference (= Vwf-Vwr) is determined whether or not a predetermined threshold is exceeded, and the slip state value exceeds the predetermined threshold Sometimes, it is determined that the rear wheel tends to slip, that is, the rear wheel braking force has reached the saturation region. The brake pressure determination unit 50b refers to the master brake pressure Pb to determine whether or not it has reached the predetermined pressure Pth. When it is determined that the master brake pressure Pb has reached the predetermined pressure Pth, It is determined that the braking force has reached the predetermined value and the actual braking force distribution ratio matches the ideal braking force distribution ratio in the light load state (the master brake pressure Pb is the predetermined pressure Pth). It may be determined that the brake pedal depression amount θb has reached a predetermined amount, instead of having reached. The braking force distribution control unit 50c is configured to control the brake pressure supplied to the wheel cylinders of the front and rear wheels in a manner described in detail later based on the determinations of the rear wheel slip determination unit 50a and the brake pressure determination unit 50b. Controls components such as circuit valves. It should be understood that the configuration of FIG. 1C is realized by processing operations of the CPU and other components in accordance with a program stored in advance in a memory device in the electronic control unit 50. .

装置の作動
図２を再度参照して、本発明の制動力制御装置に於いては、前輪制動力が図中白丸にて示された所定値に到達するまで、即ち、マスタブレーキ圧Ｐｂが所定圧Ｐｔｈに到達するまで、後輪制動力がその車両の軽積状態での理想制動力配分の場合の後輪制動力よりも下回るよう前後輪制動力配分が設定される。軽積状態での理想制動力配分は、予め車両の諸元から求めておくことができるので、所定圧Ｐｔｈは、予め設定しておくことが可能である。そして、マスタブレーキ圧Ｐｂが所定圧Ｐｔｈに到達したとき、後輪のスリップ傾向が検出されなければ、後輪に於いて制動力が限界に到達するまで余裕があると判断される。そこで、図中の矢印の如く、前輪制動力に対する後輪制動力の変化勾配が、マスタブレーキ圧Ｐｂが所定圧Ｐｔｈに到達する前までよりも増大されるよう後輪のホイールシリンダへ供給するブレーキ圧を前輪のホイールシリンダへ供給されるブレーキ圧（マスタブレーキ圧）よりも高く設定し、これにより、後輪制動力をより有効に使用できるようにする。また、この場合、車両全体の制動力も増大されることになるので、ブレーキペダルの踏込量に対して発生される総制動力が増大し、積車状態（荷台に積載物が積載されている状態）に於ける制動操作が容易になることが期待される（比較的低いペダル踏込量であっても高い制動力が得られることとなる。）。 Referring to operation diagram 2 of the device again, is at the brake force control apparatus of the present invention, until the front wheel braking force reaches a predetermined value shown in in FIG open circles, i.e., the master brake pressure Pb is given Until the pressure Pth is reached, the front and rear wheel braking force distribution is set so that the rear wheel braking force is lower than the rear wheel braking force in the case of the ideal braking force distribution in the lightly loaded state of the vehicle. Since the ideal braking force distribution in the light load state can be obtained in advance from the specifications of the vehicle, the predetermined pressure Pth can be set in advance. When the master brake pressure Pb reaches the predetermined pressure Pth, if no slip tendency of the rear wheels is detected, it is determined that there is a margin until the braking force reaches the limit at the rear wheels. Therefore, as shown by the arrows in the figure, the brake supplied to the wheel cylinders of the rear wheels so that the gradient of change of the rear wheel braking force relative to the front wheel braking force is increased more than before the master brake pressure Pb reaches the predetermined pressure Pth. The pressure is set higher than the brake pressure (master brake pressure) supplied to the wheel cylinder of the front wheel, so that the rear wheel braking force can be used more effectively. In this case, since the braking force of the entire vehicle is also increased, the total braking force generated with respect to the depression amount of the brake pedal is increased, and the vehicle is loaded (the load is loaded on the loading platform). It is expected that the braking operation in the state will be easy (a high braking force can be obtained even with a relatively low pedal depression amount).

図３は、本発明の制動力制御装置の制動力配分制御部５０ｃに於ける前後輪のホイールシリンダへ供給されるブレーキ圧を制御する処理作動をフローチャートの形式にて表したものである。なお、図示の処理は、車両の走行中、所定の制御サイクルにて繰り返し実行される。   FIG. 3 shows a processing operation for controlling the brake pressure supplied to the wheel cylinders of the front and rear wheels in the braking force distribution control unit 50c of the braking force control apparatus of the present invention in the form of a flowchart. The illustrated process is repeatedly executed in a predetermined control cycle while the vehicle is traveling.

同図を参照して、制動力配分制御部５０ｃの処理に於いては、まず、後輪スリップ判定部５０ａからの情報によって後輪にスリップ傾向があるか否かを判定する（ステップ１０）。後輪にスリップ傾向があることが検出されていなければ、ブレーキ圧判定部５０ｂからの情報を参照し、マスタブレーキ圧Ｐｂが所定圧Ｐｔｈに到達しているか否かが判定され（ステップ２０）、
Ｐｂ＜Ｐｔｈ …（１）
であれば、前輪ホイールシリンダ圧Ｐｂｆ、後輪ホイールシリンダ圧Ｐｂｒには、マスタブレーキ圧Ｐｂがそのまま設定され、それぞれのブレーキ圧が各シリンダへ供給される（ステップ３０）。一方、マスタブレーキ圧Ｐｂが所定圧Ｐｔｈに到達している場合、即ち、
Ｐｂ≧Ｐｔｈ …（２）
であれば、前輪ホイールシリンダ圧Ｐｂｆ、後輪ホイールシリンダ圧Ｐｂｒは、
Ｐｂｆ←Ｐｂ； Ｐｂｒ←Ｐｔｈ＋Ｋ（Ｐｂ−Ｐｔｈ） …（３）
と設定され、各シリンダへ対応するブレーキ圧が供給される。ここで、Ｋは、Ｋ＞１．０にて設定される任意の定数係数である。従って、図２に例示されている如く、図中白丸の点に対応する条件（２）が成立した後、マスタブレーキ圧Ｐｂが増大するときには、後輪ホイールシリンダ圧Ｐｂｒには、前輪ホイールシリンダ圧Ｐｂｆよりも高いブレーキ圧が供給され、これにより、制動力配分がそれまでよりも後輪側に偏倚されることとなる。 Referring to the figure, in the processing of braking force distribution control unit 50c, first, it is determined whether or not the rear wheel has a slip tendency based on information from rear wheel slip determination unit 50a (step 10). If it is not detected that the rear wheel has a slip tendency, it is determined whether or not the master brake pressure Pb has reached the predetermined pressure Pth with reference to the information from the brake pressure determination unit 50b (step 20).
Pb <Pth (1)
If so, the master brake pressure Pb is set as it is for the front wheel cylinder pressure Pbf and the rear wheel cylinder pressure Pbr, and the respective brake pressures are supplied to the cylinders (step 30). On the other hand, when the master brake pressure Pb has reached the predetermined pressure Pth, that is,
Pb ≧ Pth (2)
If so, the front wheel cylinder pressure Pbf and the rear wheel cylinder pressure Pbr are
Pbf ← Pb; Pbr ← Pth + K (Pb−Pth) (3)
The brake pressure corresponding to each cylinder is supplied. Here, K is an arbitrary constant coefficient set when K> 1.0. Therefore, as illustrated in FIG. 2, when the master brake pressure Pb increases after the condition (2) corresponding to the white circle in the drawing is satisfied, the rear wheel cylinder pressure Pbr includes the front wheel cylinder pressure. A brake pressure higher than Pbf is supplied, whereby the braking force distribution is biased to the rear wheel side than before.

なお、ステップ１０に於いて、後輪にスリップ傾向があると検出されたときには、その時点で、後輪ブレーキ圧が保持され（スリップ５０）、これにより、後輪制動力の増大が制限されてよい。   When it is detected in step 10 that the rear wheel has a slip tendency, the rear wheel brake pressure is maintained at that point (slip 50), thereby limiting the increase in the rear wheel braking force. Good.

上記の処理作動に於いて理解されるべきことは、車両の重量を検出することなく、前後輪の制動力配分が変更されるようになっている点である。上記までの説明から理解される如く、車両の積載重量が大きいほど、後輪の垂直荷重が増大し、これにより、後輪制動力の限界が大きくなる。そこで、従来の装置のいくつかに於いては、車両重量を検出し、車両の積載重量の増大に伴う後輪制動力の限界の増大に合わせて制動力配分を変更するといった手法が取られていた。しかしながら、本発明の装置に於いては、車両重量検出を要することなく、車両の積載重量の増大に伴う後輪制動力の限界の増大に合わせた制動力配分の変更を行うことが可能となる。   What should be understood in the above processing operation is that the braking force distribution of the front and rear wheels is changed without detecting the weight of the vehicle. As understood from the above description, the larger the vehicle loading weight, the greater the vertical load on the rear wheels, thereby increasing the limit of the rear wheel braking force. Therefore, in some of the conventional devices, a method is adopted in which the vehicle weight is detected and the braking force distribution is changed in accordance with an increase in the rear wheel braking force limit accompanying an increase in the vehicle loading weight. It was. However, in the apparatus of the present invention, it is possible to change the braking force distribution in accordance with the increase in the limit of the rear wheel braking force accompanying the increase in the loaded weight of the vehicle, without detecting the vehicle weight. .

以上の説明は、本発明の実施の形態に関連してなされているが、当業者にとつて多くの修正及び変更が容易に可能であり、本発明は、上記に例示された実施形態のみに限定されるものではなく、本発明の概念から逸脱することなく種々の装置に適用されることは明らかであろう。   Although the above description has been made in relation to the embodiment of the present invention, many modifications and changes can be easily made by those skilled in the art, and the present invention is limited to the embodiment exemplified above. It will be apparent that the invention is not limited and applies to various devices without departing from the inventive concept.

例えば、図示の実施形態に於いては、通常時の前後輪制動力配分が軽積状態の理想制動力配分に沿うように設定されているが、通常時の前後輪制動力配分の設定に於いて参照されるべき積載状態は、必ずしも軽積状態でなくてもよく、空積状態又は任意の比較的軽い積載状態が参照され、そのときの理想制動力配分に沿うように通常時の前後輪制動力配分が設定されてよい。従って、マスタブレーキ圧Ｐｂに対する所定圧Ｐｔｈは、任意の積載状態の理想制動力配分に基づいて決定されてよい。また、図示の実施形態に於いては、通常時の前後輪制動力制御に於いて、前後輪のホイールシリンダへ等圧にてブレーキ圧が供給されるようになっているが、通常時の前後輪制動力制御時でも前後輪のホイールシリンダへ異なるブレーキ圧が供給されるようになっていてもよい。重要なことは、前後輪制動力配分比が予め想定された理想制動力配分比に一致したときに後輪にスリップ傾向がないときには、その後、後輪制動力の配分が増大されるということである。   For example, in the illustrated embodiment, the normal front / rear wheel braking force distribution is set so as to follow the ideal braking force distribution in the light load state, but the normal front / rear wheel braking force distribution is set. The loading state to be referred to is not necessarily a lightly loaded state, but refers to an unloaded state or any relatively lightly loaded state, and normal front and rear wheels so as to follow the ideal braking force distribution at that time A braking force distribution may be set. Therefore, the predetermined pressure Pth with respect to the master brake pressure Pb may be determined based on the ideal braking force distribution in an arbitrary loaded state. In the illustrated embodiment, in the normal front and rear wheel braking force control, the brake pressure is supplied to the wheel cylinders of the front and rear wheels at equal pressure. Different brake pressures may be supplied to the front and rear wheel cylinders even during wheel braking force control. What is important is that, when the rear wheel braking force distribution ratio matches the ideal braking force distribution ratio assumed in advance, the rear wheel braking force distribution is increased when the rear wheel has no slip tendency. is there.

更に、制動系装置は、電磁式の制動系装置であってもよく、その場合も、図２に例示されている如く、前後輪制動力配分比が予め想定された理想制動力配分比に一致したときに後輪にスリップ傾向がないときには、その後、後輪制動力の配分が増大されるよう制御される。   Further, the braking system device may be an electromagnetic braking system device. In this case, the front-rear wheel braking force distribution ratio matches the presumed ideal braking force distribution ratio as illustrated in FIG. If the rear wheel does not tend to slip, the rear wheel braking force distribution is controlled to be increased thereafter.

１０…車両
１２ｆ，fl，fr…前輪
１２ｒ，rl，rr…後輪
１４…荷台
４０…制動系装置
４４…ブレーキペダル
４２fl,fr,rl,rr…ホイールシリンダ
４５…ブレーキバルブ
５０…電子制御装置
Ｓ…積載物
DESCRIPTION OF SYMBOLS 10 ... Vehicle 12f, fl, fr ... Front wheel 12r, rl, rr ... Rear wheel 14 ... Loading platform 40 ... Braking system device 44 ... Brake pedal 42fl, fr, rl, rr ... Wheel cylinder 45 ... Brake valve 50 ... Electronic control unit S ... load

Claims (6)

車両の制動力制御装置であって、前記車両の前輪の制動力が所定の制動力値より大きいときに前記車両の後輪の制動力が前記車両の所定の積載状態での前後輪理想制動力配分に於ける後輪の制動力に到達するよう前記車両の前後輪制動力配分比が設定され、前記車両の後輪の制動力が前記車両の所定の積載状態での前後輪理想制動力配分に於ける後輪の制動力に到達したか否かを判定する第一の判定部と、前記車両の後輪のスリップ状態値が所定閾値を超えたか否かを判定する第二の判定部と、前記第一の判定部が前記後輪の制動力が前記車両の所定の積載状態での前後輪理想制動力配分に於ける後輪の制動力に到達したことを判定したときに前記第二の判定部が前記後輪のスリップ状態値が前記所定閾値を超えたと判定していないときには、前記車両の前輪の制動力に対する前記後輪の制動力の配分を増大する制動力配分制御部とが設けられていることを特徴とする装置。   A braking force control device for a vehicle, wherein when the braking force of the front wheels of the vehicle is greater than a predetermined braking force value, the braking force of the rear wheels of the vehicle is an ideal front and rear wheel braking force in a predetermined loading state of the vehicle. The front-rear wheel braking force distribution ratio of the vehicle is set so as to reach the rear-wheel braking force in the distribution, and the rear-wheel ideal braking force distribution in the predetermined loading state of the vehicle is set. A first determination unit that determines whether or not the braking force of the rear wheel has reached, and a second determination unit that determines whether or not a slip state value of the rear wheel of the vehicle exceeds a predetermined threshold value When the first determination unit determines that the braking force of the rear wheel has reached the braking force of the rear wheel in the ideal braking force distribution of the front and rear wheels in a predetermined loading state of the vehicle, When the determination part of the rear wheel does not determine that the slip state value of the rear wheel exceeds the predetermined threshold value Apparatus characterized by a braking force distribution control unit to increase the proportion of the braking force of the rear wheel is provided for the front wheel braking force of the vehicle. 請求項１の装置であって、前記制動力配分制御部による前記後輪の制動力の配分の増大が実行された後の前記車両の前輪の制動力に対する後輪の制動力の変化勾配が前記制動力配分制御部による前記後輪の制動力の配分の増大が実行される前の前記車両の前輪の制動力に対する後輪の制動力の変化勾配よりも大きいことを特徴とする装置。   The apparatus according to claim 1, wherein a change gradient of the braking force of the rear wheel with respect to the braking force of the front wheel of the vehicle after the increase of the distribution of the braking force of the rear wheel by the braking force distribution control unit is executed. The apparatus is characterized in that the braking force distribution control unit is larger than the change gradient of the braking force of the rear wheel with respect to the braking force of the front wheel of the vehicle before the increase in the distribution of the braking force of the rear wheel is executed. 請求項１又は２の装置であって、前記車両の所定の積載状態が軽積状態であることを特徴とする装置。   The apparatus according to claim 1, wherein the predetermined loading state of the vehicle is a light loading state. 請求項１乃至３のいずれかの装置であって、前記第二の判定部が前記後輪のスリップ状態値が前記所定閾値を超えたと判定したときには、前記制動力配分制御部が前記後輪の制動力の増大を制限することを特徴とする装置。   4. The device according to claim 1, wherein when the second determination unit determines that the slip state value of the rear wheel exceeds the predetermined threshold value, the braking force distribution control unit determines that the rear wheel has a slip state value. A device that limits an increase in braking force. 車両の制動力制御装置であって、前記車両の前輪の制動力が所定の制動力値より小さいときには前後輪の制動力配分比が前記車両の軽積時の前後輪理想制動力配分比よりも前輪側に偏っており、前記車両の前輪の制動力が前記所定の制動力値に到達したときに前記車両の後輪制動力が飽和領域に達していない場合には、前記前後輪の制動力配分比が後輪側に増大されるよう前後輪の制動力配分を実行する装置。   A braking force control apparatus for a vehicle, wherein when the braking force of the front wheels of the vehicle is smaller than a predetermined braking force value, the braking force distribution ratio of the front and rear wheels is larger than the ideal braking force distribution ratio of the front and rear wheels when the vehicle is lightly loaded. If the rear wheel braking force of the vehicle does not reach the saturation region when the braking force of the front wheel of the vehicle reaches the predetermined braking force value, the braking force of the front and rear wheels is biased to the front wheel side. A device that executes the braking force distribution of the front and rear wheels so that the distribution ratio is increased to the rear wheel side. 車両の流体圧式制動装置のための制動力制御装置であって、前記車両の前輪及び後輪のブレーキ圧が所定の圧力値より小さいときには前後輪の制動力配分比が前記車両の軽積時の前後輪理想制動力配分比よりも前輪側に偏っており、前記前後輪の制動力配分比が前記車両の軽積時の前後輪理想制動力配分比に到達したときに前記車両の後輪制動力が飽和領域に達していない場合には、前記前後輪の制動力配分比がそれまでよりも後輪側に偏倚されるよう前後輪の制動力配分を実行する装置。
A braking force control device for a fluid pressure braking device for a vehicle, wherein when the brake pressures of the front and rear wheels of the vehicle are smaller than a predetermined pressure value, the braking force distribution ratio of the front and rear wheels is low when the vehicle is lightly loaded. When the braking force distribution ratio of the front and rear wheels reaches the front and rear wheel ideal braking force distribution ratio when the vehicle is lightly loaded, the rear wheel control of the vehicle is biased toward the front wheel side. When the power does not reach the saturation region, the device for executing the braking force distribution of the front and rear wheels so that the braking force distribution ratio of the front and rear wheels is biased to the rear wheel side than before.
JP2009138174A 2009-06-09 2009-06-09 Braking force control device of vehicle Pending JP2010284990A (en)

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US10471939B2 (en) 2016-11-24 2019-11-12 Toyota Jidosha Kabushiki Kaisha Braking control apparatus for vehicle

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