JP2897332B2 - Brake control device for rear two-axle vehicle - Google Patents

Description

【発明の詳細な説明】 ［産業上の利用分野］ 本発明は後２軸車両の制動時、車輪ロツクを抑えるた
めに、ブレーキの配管系統をを前・後後輪ブレーキを駆
動する第１の配管系統と、前輪ブレーキを駆動する第２
の配管系統とに分け、前後輪ブレーキの圧力失陥時、第
２の配管系統を後後輪ブレーキへ接続して制動力を補
う、後２軸車両のブレーキ制御装置に関するものであ
る。DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a first system for driving a front / rear wheel brake through a brake piping system in order to suppress wheel lock during braking of a rear two-axle vehicle. Piping system and the second to drive the front wheel brake
The present invention relates to a brake control device for a rear two-axle vehicle, in which a second piping system is connected to a rear rear wheel brake to supplement a braking force when pressure of front and rear wheel brakes is lost.

［従来の技術］ 第３図に示すように、従来の後２軸車両のブレーキ制
御装置は、ブレーキペダル７によりブレーキ弁６を開く
と、空気タンク８の加圧空気が２つの配管系統を経て油
圧に変換され、前輪ブレーキ３と後後輪ブレーキ16,16a
とに作用し、同時に前後輪ブレーキ13,13aに作用する。
すなわち、空気タンク８の加圧空気はブレーキ弁６、管
21、電磁圧力制御弁５を経て倍力装置４を駆動し、管22
を経て前輪ブレーキ３へ、管24を経て後後輪ブレーキ1
6,16aへそれぞれ油圧を送る。また、空気タンク８の加
圧空気はブレーキ弁６、管26、電磁圧力制御弁9,9aを経
て倍力装置10,10aを駆動し、管28,28aを経て前後輪ブレ
ーキ13,13aへ油圧を送る。[Prior Art] As shown in FIG. 3, when a brake valve 6 is opened by a brake pedal 7, the pressurized air in an air tank 8 passes through two piping systems. Converted to hydraulic pressure, front wheel brake 3 and rear rear wheel brake 16, 16a
And simultaneously act on the front and rear wheel brakes 13, 13a.
That is, the pressurized air in the air tank 8 is supplied to the brake valve 6 and the pipe.
21. Drive the booster 4 via the electromagnetic pressure control valve 5, and
Through to the front wheel brake 3 and through the tube 24 to the rear wheel brake 1
Send hydraulic pressure to 6,16a respectively. The pressurized air in the air tank 8 drives the boosters 10, 10a through the brake valve 6, the pipe 26, the electromagnetic pressure control valves 9, 9a, and the hydraulic pressure to the front and rear wheel brakes 13, 13a through the pipes 28, 28a. Send.

電磁圧力制御弁5,9,9aは、左右の前輪２に配設した１
対の回転数センサと、左右の前後輪12に配設した１対の
回転数センサとの信号を入力とする電子制御装置の出力
信号に基づき、各倍力装置4,10,10aへ送る空気圧を加減
する。各倍力装置4,10,10aは入力空気圧に比例した出力
油圧を各車輪ブレーキへ加え、車輪ロツクを防止するよ
うに働く。前後輪と後後輪がともに駆動される後２軸車
両でも同様である。このような構成は例えば特開昭60−
215458号公報に開示されている。The electromagnetic pressure control valves 5, 9, and 9a are disposed on the left and right front wheels 2.
Based on the output signals of the electronic control unit which receives the signals of the pair of rotation speed sensors and the pair of rotation speed sensors disposed on the left and right front and rear wheels 12, the air pressure to be sent to each booster 4, 10, 10a To adjust. Each of the boosters 4, 10, and 10a applies an output oil pressure proportional to the input air pressure to each wheel brake, and serves to prevent wheel lock. The same applies to a rear two-axis vehicle in which both front and rear wheels and rear rear wheels are driven. Such a configuration is disclosed in, for example,
It is disclosed in Japanese Patent Publication No. 215458.

上述した従来の後２軸車両のブレーキ制御装置では、
次のような問題がある。In the conventional rear-axle vehicle brake control device described above,
There are the following problems.

（ａ） 前輪ブレーキと後後輪ブレーキが同一の配管系
統で作動されるから、後後輪ロツクが生じやすく、前輪
の回転数センサをなくし、後後輪に配設した回転数セン
サの信号に基づき電磁圧力制御弁５を制御すると、後輪
ロツクを防止できても左右の車輪で摩擦状態が異なる路
面での車両姿勢を修正できなくなる。(A) Since the front wheel brakes and the rear rear wheel brakes are operated by the same piping system, the rear and rear wheels are likely to be locked, the front wheel speed sensor is eliminated, and the signals of the speed sensors provided for the rear and rear wheels are reduced. If the electromagnetic pressure control valve 5 is controlled on the basis of this, even if the rear wheel lock can be prevented, the vehicle posture on a road surface having different friction states between the left and right wheels cannot be corrected.

（ｂ） 全ての車輪に設けた回転数センサの信号に基づ
き電磁圧力制御弁を制御することが好ましいが、これで
はコストが高くなる。(B) It is preferable to control the electromagnetic pressure control valve based on the signals of the rotation speed sensors provided on all the wheels, but this increases the cost.

（ｃ） 前輪ブレーキと後後輪ブレーキへ圧油を送る倍
力装置の容量と、前後輪ブレーキへ圧油を送る倍力装置
の容量は、各車輪のブレーキ負担割合に対応したものと
されるので、車輪ロツク防止制御（ABS）状態で、第１
の配管系統の応答性と第２の配管系統の応答性とに差が
生じ、車輪ロツク防止性能を十分に発揮できない。(C) The capacity of the booster that sends pressurized oil to the front and rear rear wheel brakes and the capacity of the booster that sends pressurized oil to the front and rear wheel brakes correspond to the brake load ratio of each wheel. Therefore, in the wheel lock prevention control (ABS) state,
A difference occurs between the responsiveness of the second piping system and the responsiveness of the second piping system, and the wheel lock prevention performance cannot be sufficiently exhibited.

（ｄ） 前輪ブレーキを駆動する配管系統と前・後後輪
を駆動する配管系統とに分けて、各配管系統の油圧を制
御すると、前・後後輪ブレーキの配管系統の失陥時必要
な制動力が得られなくなる。(D) Dividing the piping system for driving the front wheel brakes and the piping system for driving the front and rear wheels, and controlling the hydraulic pressure of each piping system, it is necessary to control the hydraulic system of the front and rear wheel brakes in the event of a failure. Braking force cannot be obtained.

［発明が解決しようとする問題点］ 本発明の目的は上述の問題に鑑み、ブレーキの配管系
統を前輪ブレーキを駆動する配管系統と、前・後後輪ブ
レーキを駆動する配管系統とに分けて、前・後後輪ロツ
クを効果的に防止する一方、前後輪ブレーキの圧力失陥
時にも後後輪ブレーキを働かせて制動力の不足を補う、
後２軸車両のブレーキ制御装置を提供することにある。[Problems to be Solved by the Invention] In view of the above-described problems, an object of the present invention is to divide a brake piping system into a piping system for driving front wheel brakes and a piping system for driving front / rear wheel brakes. , While effectively preventing the front and rear wheels from locking, the rear rear wheel brakes are used to compensate for the lack of braking force even when the front and rear wheel brakes fail.
An object of the present invention is to provide a brake control device for a rear two-axle vehicle.

［問題点を解決するための手段］ 上記目的を達成するために、本発明の構成は流体圧源
が第１の配管系統により第１の圧力制御弁を経て前後輪
ブレーキと後後輪ブレーキに、第２の配管系統により第
２の圧力制御弁を経て前輪ブレーキにそれぞれ接続され
る後２軸車両のブレーキ制御装置において、流体圧源の
流体圧を前後輪ブレーキへ送る第１の圧力制御弁の出口
を後後輪ブレーキに接続する第１の位置と、流体圧源の
流体圧を前輪ブレーキへ送る第２の圧力制御弁の出口を
後後輪ブレーキに接続する第２の位置とに切り換わる電
磁切換弁を備え、第１の圧力制御弁の出口側に圧力セン
サを設け、前記電磁切換弁を通常は第１の位置とし、圧
力センサの検出圧が所定値以下の時第２の位置とする電
子制御装置を備えたことを特徴とする。[Means for Solving the Problems] In order to achieve the above object, according to the configuration of the present invention, a fluid pressure source is supplied to a front and rear wheel brake and a rear rear wheel brake via a first pressure control valve by a first piping system. A first pressure control valve for sending fluid pressure of a fluid pressure source to front and rear wheel brakes in a brake control device for a rear two-axle vehicle connected to a front wheel brake via a second pressure control valve via a second piping system. At a first position connecting the rear of the vehicle to the rear rear wheel brake, and at a second position connecting the outlet of the second pressure control valve for transmitting the fluid pressure of the fluid pressure source to the front wheel brake to the rear rear wheel brake. A pressure sensor is provided at an outlet side of the first pressure control valve, and the electromagnetic switch valve is normally set to the first position, and the second position is set when the pressure detected by the pressure sensor is equal to or lower than a predetermined value. The electronic control device described above is provided.

［作用］ 通常の状態では、第１の配管系統は前・後後輪ブレー
キに接続し、第２の配管系統は前輪ブレーキに接続する
ので、制動時の荷重の前方移動に対応して前・後後輪の
ロツクを効果的に防止できる。[Operation] In a normal state, the first piping system is connected to the front / rear wheel brakes, and the second piping system is connected to the front wheel brakes. Locking of the rear rear wheel can be effectively prevented.

一方、前後輪ブレーキの圧力失陥時は、これを検出す
る圧力センサの信号に基づく電子制御装置の出力信号に
より電磁切換弁を切り換え、第１の配管系統を後後輪ブ
レーキへ接続して制動力の不足を補う。On the other hand, when the pressure of the front and rear wheel brakes fails, the electromagnetic switching valve is switched by an output signal of the electronic control unit based on the signal of the pressure sensor for detecting the pressure, and the first piping system is connected to the rear rear wheel brake to control the brake. Make up for lack of power.

［発明の実施例］ 第１図は本発明による後２軸車両のブレーキ制御装置
の回路図である。ブレーキペダル７により操作されるブ
レーキ弁６は、空気タンク８の加圧空気を第２、第１の
配管系統へ送る。空気タンク８はブレーキ弁６、管21、
電磁圧力制御弁５、倍力装置４、管22を経て前輪ブレー
キ３へ接続される。また、空気タンク８はブレーキ弁
６、管26から左右に分れて管27,27a、電磁圧力制御弁9,
9a、倍力装置10,10a、管28,28aを経て左右の前後輪ブレ
ーキ13,13aへ接続され、さらに、管28,28a、電磁切換弁
14,14a、管29,29aを経て左右の後後輪ブレーキ16,16aへ
接続される。FIG. 1 is a circuit diagram of a brake control device for a rear two-axle vehicle according to the present invention. The brake valve 6 operated by the brake pedal 7 sends the pressurized air in the air tank 8 to the second and first piping systems. The air tank 8 has a brake valve 6, a pipe 21,
The electromagnetic pressure control valve 5, the booster 4, and the pipe 22 are connected to the front wheel brake 3. Further, the air tank 8 is divided into left and right from the brake valve 6 and the pipe 26, and the pipes 27 and 27a, the electromagnetic pressure control valve 9,
9a, boosters 10, 10a, connected to left and right front and rear wheel brakes 13, 13a via pipes 28, 28a, and further, pipes 28, 28a, electromagnetic switching valve
The right and left rear rear wheel brakes 16, 16a are connected via 14, 14a and pipes 29, 29a.

本発明は前後輪ブレーキ13,13aの圧力失陥に備えて、
第２の配管系統が後後輪ブレーキ16,16aへ接続可能とさ
れる。すなわち、管22が管24、電磁切換弁14、14a、管2
9,29aを経て後後輪ブレーキ16,16aへ接続可能とされ
る。The present invention prepares for the pressure failure of the front and rear wheel brakes 13 and 13a,
The second piping system can be connected to the rear rear wheel brakes 16, 16a. That is, the pipe 22 is the pipe 24, the electromagnetic switching valves 14, 14a, the pipe 2
Via 9,29a, it can be connected to the rear rear wheel brakes 16,16a.

車輪ロツクを防止する電磁圧力制御弁5,9,9aと、前後
輪ブレーキ13,13aの圧力失陥に備える電磁切換弁14,14a
とを制御するために、ブレーキ弁７に制動時閉じるブレ
ーキスイツチ30が、左右の前輪２に回転数センサ17,17a
が、左右の前後輪12に回転数センサ18,18aが、管29,29a
に圧力センサ19,19aがそれぞれ配設される。ブレーキス
イツチ30、回転数センサ17,17a、回転数センサ18,18a、
圧力センサ19,19aの各信号は電子制御装置20へ加えら
れ、電子制御装置20は電磁圧力制御弁5,9,9aへ出力信号
を送り、また前後輪ブレーキ13,13aの失陥時、電磁切換
弁14,14aへ出力信号を送る。Electromagnetic pressure control valves 5, 9, 9a for preventing wheel lock, and electromagnetic switching valves 14, 14a for pressure failure of front and rear wheel brakes 13, 13a
The brake switch 30 which is closed when braking is applied to the brake valve 7 is provided to the left and right front wheels 2 to control the rotation speed sensors 17, 17a.
However, rotation speed sensors 18, 18a are provided on the left and right front and rear wheels 12, and pipes 29, 29a.
Are provided with pressure sensors 19 and 19a, respectively. Brake switch 30, rotation speed sensors 17, 17a, rotation speed sensors 18, 18a,
Each signal of the pressure sensors 19, 19a is applied to an electronic control unit 20, which sends an output signal to the electromagnetic pressure control valves 5, 9, 9a. An output signal is sent to the switching valves 14, 14a.

次に、本発明による後２軸車両のブレーキ制御装置の
作動について説明する。通常の状態では、電磁切換弁1
4,14aは第１図に示す第１の位置にあり、管28と管29を
接続し、管28aと管29aを接続する。したがつて、制動時
ブレーキペダル７を踏むと、空気タンク８の加圧空気が
ブレーキ弁６、管21、電磁圧力制御弁５を経て倍力装置
４へ送られ、倍力装置４から圧油が管22を経て前輪ブレ
ーキ３へ送られる。Next, the operation of the brake control device for a rear two-axle vehicle according to the present invention will be described. Under normal conditions, the solenoid-operated switching valve 1
4, 14a are in the first position shown in FIG. 1 and connect the pipes 28 and 29, and connect the pipes 28a and 29a. Accordingly, when the brake pedal 7 is depressed during braking, pressurized air in the air tank 8 is sent to the booster 4 through the brake valve 6, the pipe 21, and the electromagnetic pressure control valve 5, and the booster 4 pressurizes the hydraulic oil. Is sent to the front wheel brake 3 via the pipe 22.

また、空気タンク８の加圧空気がブレーキ弁６、管2
6、管27,27a、電磁圧力制御弁9,9aを経て倍力装置10,10
aへ送られる。倍力装置10,10aから圧油が管28,28aを経
て前後輪ブレーキ13,13aへ送られる。同時に、倍力装置
10,10aから圧油が管28,28a、電磁切換弁14,14a、管29,2
9aを経て後後輪ブレーキ16,16aへ送られる。この状態で
は、第２の配管系統の制動力が前輪２に加えられ、第１
の配管系統の制動力が駆動輪である前後輪12と、従動輪
または駆動輪である後後輪15とに加えられる。電子制御
装置20の出力信号により、電磁圧力制御弁9,9aが制御さ
れ、倍力装置10,10aから前後輪ブレーキ13,13aと後後輪
ブレーキ16,16aへ加えられる油圧が加減され、後輪ロツ
クを防止するように働く。The pressurized air in the air tank 8 is supplied to the brake valve 6 and the pipe 2
6, Boosters 10,10 via pipes 27,27a, electromagnetic pressure control valves 9,9a
sent to a. Pressure oil is sent from the boosters 10, 10a to the front and rear wheel brakes 13, 13a via the pipes 28, 28a. At the same time, booster
Pressure oil from pipes 10 and 10a, pipes 28 and 28a, solenoid directional control valves 14 and 14a, pipes 29 and 2
It is sent to the rear wheel brakes 16, 16a via 9a. In this state, the braking force of the second piping system is applied to the front wheels 2 and the first
The braking force of the piping system is applied to the front and rear wheels 12 which are driving wheels and the rear rear wheel 15 which is a driven wheel or a driving wheel. The electromagnetic pressure control valves 9, 9a are controlled by the output signal of the electronic control unit 20, and the hydraulic pressure applied from the boosters 10, 10a to the front and rear wheel brakes 13, 13a and the rear rear wheel brakes 16, 16a is adjusted. Works to prevent wheel lock.

一方、前後輪ブレーキ13,13aに圧力失陥が生じると、
圧力センサ19,19aから圧力失陥信号が電子制御装置20へ
送られ、電子制御装置20の出力信号により電磁切換弁1
4,14aが第２の位置へ切り換わり、管24が管29に接続
し、管24が管29aに接続する。したがつて、空気タンク
８の加圧空気がブレーキ弁６、管21、電磁圧力制御弁５
を経て倍力装置４へ送られ、倍力装置４から圧油が管22
を経て前輪ブレーキ３へ送られる。同時に、管22から管
24、電磁切換弁14、14a、管29,29aを経て後後輪ブレー
キ16,16aへ送られる。これにより、制動力の低下が補わ
れる。On the other hand, if pressure failure occurs in the front and rear wheel brakes 13, 13a,
A pressure failure signal is sent from the pressure sensors 19 and 19a to the electronic control unit 20, and the electromagnetic switching valve 1 is
4,14a switches to the second position, tube 24 connects to tube 29, and tube 24 connects to tube 29a. Therefore, the pressurized air in the air tank 8 is supplied to the brake valve 6, the pipe 21, the electromagnetic pressure control valve 5.
The pressure oil is sent to the booster 4 through the
And is sent to the front wheel brake 3. At the same time, tube 22 to tube
24, sent to the rear rear wheel brakes 16, 16a via the electromagnetic switching valves 14, 14a and the pipes 29, 29a. As a result, a reduction in the braking force is compensated for.

第２図は上述の制御を行う電子制御装置のプログラム
の流れ図である。図において、p11〜p19は流れ図の各ス
テツプを示す。制御プログラムは所定時間毎に繰り返し
演算される。p11でスタートし、p12でブレーキスイツチ
30によりブレーキペダル７が踏まれているか否かを判別
する。ブレーキペダル７が踏まれていない場合はp12へ
戻り、ブレーキペダル７が踏まれている場合は、p13で
回転数センサ17,17a,18,18aによる前輪２と前後輪12の
回転数を読み込む。p14で車輪ロツクを生じる条件にあ
るか否か、例えば前輪２の回転数nfと前後輪12の回転数
nrとの差が所定値ｄより大きいか否かを判別する。FIG. 2 is a flowchart of a program of the electronic control device for performing the above-described control. In the figure, p11 to p19 indicate each step in the flowchart. The control program is repeatedly calculated every predetermined time. Start with p11, brake switch with p12
At 30, it is determined whether or not the brake pedal 7 is depressed. If the brake pedal 7 is not depressed, the process returns to p12. If the brake pedal 7 is depressed, the rotational speeds of the front wheel 2 and the front and rear wheels 12 by the rotational speed sensors 17, 17a, 18, 18a are read at p13. Whether or not the conditions for generating the wheel lock in p14 are satisfied, for example, the rotation speed nf of the front wheel 2 and the rotation speed of the front and rear wheels 12
It is determined whether or not the difference from nr is greater than a predetermined value d.

p14で回転数の差が所定値ｄよりも小さい場合はp12へ
戻る。p14で回転数の差が所定値ｄよりも大きい場合
は、p15で圧力センサ19,19aにより管28,28aの油圧が所
定値ｅよりも大きいか否か（配管系統が圧力失陥してい
ないか否か）を判別する。p15で管28,28aの油圧が所定
値ｅよりも小さい場合は、p16で電磁切換弁14,14aを第
２の位置へ切り換え、p19へ進む。p15で管28,28aの油圧
が所定値ｅよりも大きい場合は、p17で電磁切換弁14,14
aを第１の位置に保持し、p18で電磁圧力制御弁9,9aを作
動して倍力装置10,10aへの空気圧を減じ、p19で終了す
る。When the difference in the number of rotations is smaller than the predetermined value d in p14, the process returns to p12. If the difference between the rotation speeds is larger than the predetermined value d in p14, it is determined in p15 whether the oil pressure of the pipes 28 and 28a is larger than the predetermined value e by the pressure sensors 19 and 19a (the pressure in the piping system is not failed). Or not) is determined. If the hydraulic pressure of the pipes 28, 28a is smaller than the predetermined value e at p15, the electromagnetic switching valves 14, 14a are switched to the second position at p16, and the process proceeds to p19. If the hydraulic pressure of the pipes 28, 28a is larger than the predetermined value e at p15, the solenoid operated directional control valves 14,
a is held in the first position, the electromagnetic pressure control valves 9, 9a are operated at p18 to reduce the air pressure to the boosters 10, 10a, and the process ends at p19.

上述した実施例では、空気タンクの加圧空気がブレー
キ弁、圧力制御弁を経て倍力装置へ送られ、倍力装置か
ら所要の油圧が車輪ブレーキへ送られる形式のブレーキ
装置の場合について説明したが、本発明はこれに限定さ
れるものではなく、空気タンクの加圧空気がブレーキ
弁、圧力制御弁を経て車輪ブレーキへ送られる形式のブ
レーキ装置にも適用できる。また、本発明は前２軸・後
２軸車両のブレーキ装置にも適用できる。In the above-described embodiment, the case of the brake device in which the pressurized air in the air tank is sent to the booster via the brake valve and the pressure control valve, and the required oil pressure is sent from the booster to the wheel brakes has been described. However, the present invention is not limited to this, and can also be applied to a brake device in which pressurized air in an air tank is sent to a wheel brake via a brake valve and a pressure control valve. The present invention is also applicable to a brake device for a front two-axle and rear two-axle vehicle.

［発明の効果］ 本発明は上述のように、流体圧源が第１の配管系統に
より第１の圧力制御弁を経て前後輪ブレーキと後後輪ブ
レーキに、第２の配管系統により第２の圧力制御弁を経
て前輪ブレーキにそれぞれ接続される後２軸車両のブレ
ーキ制御装置において、流体圧源の流体圧を前後輪ブレ
ーキへ送る第１の圧力制御弁の出口を後後輪ブレーキに
接続する第１の位置と、流体圧源の流体圧を前輪ブレー
キへ送る第２の圧力制御弁の出口を後後輪ブレーキに接
続する第２の位置とに切り換わる電磁切換弁を備え、第
１の圧力制御弁の出口側に圧力センサを設け、前記電磁
切換弁を通常は第１の位置とし、圧力センサの検出圧が
所定値以下の時第２の位置とする電子制御装置を備えた
ものであるから、次のような効果を奏する。[Effects of the Invention] As described above, in the present invention, the fluid pressure source is supplied to the front and rear wheel brakes and the rear rear wheel brake through the first pressure control valve by the first piping system, and to the second piping system by the second piping system. In a brake control device for a rear two-axle vehicle that is connected to a front wheel brake via a pressure control valve, an outlet of a first pressure control valve that sends fluid pressure of a fluid pressure source to front and rear wheel brakes is connected to the rear rear wheel brake. An electromagnetic switching valve that switches between a first position and a second position that connects an outlet of a second pressure control valve that sends fluid pressure of a fluid pressure source to a front wheel brake to a rear rear wheel brake; A pressure sensor is provided on the outlet side of the pressure control valve, and the electronic control unit is configured to normally set the electromagnetic switching valve to the first position and to set the electromagnetic switching valve to the second position when the detection pressure of the pressure sensor is equal to or less than a predetermined value. Therefore, the following effects are obtained.

通常は第２の配管系統が前輪ブレーキに、第１の配管
系統が前後輪ブレーキと後後輪ブレーキにそれぞれ接続
されるので、制動時の荷重の前方移動に対応して前後輪
ブレーキと後後輪ブレーキの流体圧が第１の圧力制御弁
により減じられ、前後輪ロツクと後後輪ロツクを防止で
きる。したがつて、制動距離の短縮と車体姿勢の安定が
維持される。Normally, the second piping system is connected to the front wheel brakes and the first piping system is connected to the front and rear wheel brakes and the rear rear wheel brakes. The fluid pressure of the wheel brake is reduced by the first pressure control valve, so that the front and rear wheel lock and the rear rear wheel lock can be prevented. Accordingly, the braking distance is shortened and the vehicle body posture is kept stable.

第１の配管系統（前後輪ブレーキ）の流体圧失陥時
は、これを検出する圧力センサの信号に基づく電子制御
装置の出力信号により電磁切換弁が切り換えられ、第２
の配管系統が後後輪ブレーキへ接続されるので、制動能
力が半分以下に減じることがなく安全である。When the first piping system (front and rear wheel brakes) fails in fluid pressure, the electromagnetic switching valve is switched by the output signal of the electronic control unit based on the signal of the pressure sensor that detects the failure, and the second switching valve is switched.
Is connected to the rear rear wheel brake, so that the braking capacity is not reduced to less than half and is safe.

【図面の簡単な説明】[Brief description of the drawings]

第１図は本発明に係る後２軸車両のブレーキ制御装置の
回路図、第２図は同制御プログラムの流れ図、第３図は
従来の後２軸車両のブレーキ制御装置の回路図である。 3:前輪ブレーキ、4,10,10a:倍力装置、5,9,9a:電磁圧力
制御弁、8:空気タンク、13,13a:前後輪ブレーキ、14,14
a:電磁切換弁、16,16a:後後輪ブレーキ、17,17a,18,18
a:回転数センサ、19,19a:圧力センサ、20:電子制御装
置、30:ブレーキスイツチFIG. 1 is a circuit diagram of a brake control device for a rear two-axle vehicle according to the present invention, FIG. 2 is a flowchart of the control program, and FIG. 3 is a circuit diagram of a conventional brake control device for a rear two-axle vehicle. 3: front wheel brake, 4, 10, 10a: booster, 5, 9, 9a: electromagnetic pressure control valve, 8: air tank, 13, 13a: front and rear wheel brake, 14, 14
a: Solenoid switching valve, 16, 16a: Rear rear wheel brake, 17, 17a, 18, 18
a: speed sensor, 19, 19a: pressure sensor, 20: electronic control unit, 30: brake switch

Claims (1)

(57)【特許請求の範囲】(57) [Claims] 【請求項１】流体圧源が第１の配管系統により第１の圧
力制御弁を経て前後輪ブレーキと後後輪ブレーキに、第
２の配管系統により第２の圧力制御弁を経て前輪ブレー
キにそれぞれ接続される後２軸車両のブレーキ制御装置
において、流体圧源の流体圧を前後輪ブレーキへ送る第
１の圧力制御弁の出口を後後輪ブレーキに接続する第１
の位置と、流体圧源の流体圧を前輪ブレーキへ送る第２
の圧力制御弁の出口を後後輪ブレーキに接続する第２の
位置とに切り換わる電磁切換弁を備え、第１の圧力制御
弁の出口側に圧力センサを設け、前記電磁切換弁を通常
は第１の位置とし、圧力センサの検出圧が所定値以下の
時第２の位置とする電子制御装置を備えたことを特徴と
する後２軸車両のブレーキ制御装置。A fluid pressure source is supplied to a front and rear wheel brake and a rear wheel brake via a first pressure control valve by a first piping system, and to a front wheel brake via a second pressure control valve via a second piping system. In the brake control device for a rear two-axle vehicle connected respectively, an outlet of a first pressure control valve for sending fluid pressure of a fluid pressure source to front and rear wheel brakes is connected to a rear rear wheel brake.
And the second to send the fluid pressure of the fluid pressure source to the front wheel brake
An electromagnetic switching valve that switches an outlet of the pressure control valve to a second position connected to a rear rear wheel brake, a pressure sensor is provided at an outlet side of the first pressure control valve, and the electromagnetic switching valve is usually A brake control device for a rear two-axle vehicle, comprising: an electronic control device that is set to a first position and is set to a second position when a pressure detected by a pressure sensor is equal to or less than a predetermined value.