JP2001063552A - Normally open type solenoid valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve responsivity of switching operation of a switching valve without a possibility of its malfunction even during quick depression of a master cylinder. SOLUTION: A through hole 33 of a housing main body 31 is divided into a first area K1 in which a valve stem 34 of a master valve 5 is slidably mounted, a second area K2 with a larger diameter and a third area K3 with the largest diameter. The valve stem 34 is formed with a communicating hole and has a valve element 34a formed at its tip. A switching valve 10 has a second valve seat member 47 and a piston 48 slidably disposed with the valve stem 34 inserted therein and having an outer peripheral surface in contact with an inner surface of the third area K3, one end coming into the second area K2 and the other end which comes into contact with and departs from the second valve seat member 47. One end of the piston 48 positioned within the second area K2 to undergo approaching force of a main hydraulic channel I has a pressure receiving area which is smaller than that of the piston 48 undergoing oppositional force of the main hydraulic channel I with the switching valve 10 and the master valve 5 open and larger than that of the piston 48 undergoing the oppositional force of the main hydraulic channel I with the switching valve 10 throttled and the master valve 5 open.

Description

【発明の詳細な説明】DETAILED DESCRIPTION OF THE INVENTION

【０００１】[0001]

【発明の属する技術分野】本発明は、アンチロック制御
やトラクション制御、またはこれら両方の制御を行う車
両用ブレーキ装置に使用する常開型電磁弁に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a normally-open solenoid valve for use in a vehicle brake device for performing antilock control, traction control, or both controls.

【０００２】[0002]

【従来の技術】従来の車両用ブレーキ制御装置におい
て、ノイズの発生防止や脈動低減のために、マスタシリ
ンダから車輪ブレーキにブレーキ液を供給する主液圧流
路内に、主弁と切換弁とが直列に配置された常開型電磁
弁を介装し、アンチロック動作時に、切換弁が作動する
ようにして主液圧流路内に絞り（オリフィス）を形成
し、ブレーキ液の流量を絞ることが行われていた。かか
る常開型電磁弁は、例えば特開平８-１０４２２８号公
報等により既に知られている。2. Description of the Related Art In a conventional vehicle brake control system, a main valve and a switching valve are provided in a main hydraulic pressure passage for supplying brake fluid from a master cylinder to a wheel brake in order to prevent noise and reduce pulsation. A normally open solenoid valve arranged in series is interposed, and a throttle (orifice) is formed in the main hydraulic pressure passage so that the switching valve operates during anti-lock operation, thereby reducing the flow rate of the brake fluid. It was done. Such a normally-open solenoid valve is already known, for example, from Japanese Patent Application Laid-Open No. 8-104228.

【０００３】一例として特開平８-１０４２２８号公報
に記載の常開型電磁弁１の構造を図６を用いて、動作と
併せて概説する。通常ブレーキ時には、マスタシリンダ
から送出されたブレーキ液の液圧は、主液圧流路Ｉ（常
開型電磁弁１を基準としてマスタシリンダ側の主液圧流
路を言う）、第１液圧流路２、第１フィルタ３、第１液
圧室４、開状態の主弁５（弁孔６を有する弁座部材７と
弁軸８の先端に配置された弁体としての弁球９からな
る）、開状態の切換弁１０、下流側液圧室１１、第２液
圧室１２、第２フィルタ１３、第２液圧流路１４、主液
圧流路II（常開型電磁弁１を基準として車輪ブレーキ側
の主液圧流路を言う）を通り、車輪ブレーキに供給され
る。As an example, the structure of a normally-open solenoid valve 1 described in Japanese Patent Application Laid-Open No. 8-104228 will be outlined together with its operation with reference to FIG. During normal braking, the hydraulic pressure of the brake fluid sent from the master cylinder is determined by the main hydraulic pressure path I (refers to the main hydraulic pressure path on the master cylinder side with respect to the normally-open solenoid valve 1) and the first hydraulic pressure path 2 A first filter 3, a first hydraulic chamber 4, an open main valve 5 (consisting of a valve seat member 7 having a valve hole 6 and a valve ball 9 as a valve element disposed at the tip of a valve shaft 8), Open switching valve 10, downstream hydraulic chamber 11, second hydraulic chamber 12, second filter 13, second hydraulic flow path 14, main hydraulic flow path II (wheel brake based on normally open solenoid valve 1) Side main hydraulic flow path).

【０００４】ここで、弁軸８は、電磁石１５の可動コア
１６によって、弁座部材７に対して接離動するように駆
動される。また、切換弁１０は、下流側液圧室１１に形
成され、ピストン１７の図６中の右端が電磁石１５の固
定コア１８の壁面から離れている場合、切換弁１０は開
状態にあり、ピストン１７の右端が固定コア１８の壁面
に当接している場合、切換弁１０はピストン１７の右端
に形成された第３絞り１９が流路となって絞り状態にあ
る。[0004] Here, the valve shaft 8 is driven by the movable core 16 of the electromagnet 15 to move toward and away from the valve seat member 7. When the right end of the piston 17 in FIG. 6 is separated from the wall surface of the fixed core 18 of the electromagnet 15, the switching valve 10 is in the open state, and the switching valve 10 is in the open state. When the right end of 17 is in contact with the wall surface of the fixed core 18, the switching valve 10 is in the throttled state with the third throttle 19 formed at the right end of the piston 17 serving as a flow path.

【０００５】ブレーキ制御装置がアンチスキッドまたは
トラクション制御中において、切換弁１０が開状態で主
弁５が閉状態となると、主液圧流路Ｉから供給されるブ
レーキ液は、主弁５で断たれる。すると、主弁５の前後
に液圧差が生じ、これが規定値を超えると、弁座部材７
に形成された第２絞り２０を介して上流側液圧室２１に
伝えられている液圧と、液圧室１１、１２の圧力差によ
って、ピストン１７が作動（右方向へ移動）する。ピス
トン１７の右端が固定コア１８の壁面に当接すると、切
換弁１０は絞り状態に切換わる。When the switching valve 10 is opened and the main valve 5 is closed during the anti-skid or traction control by the brake control device, the brake fluid supplied from the main hydraulic pressure passage I is cut off by the main valve 5. It is. Then, a hydraulic pressure difference occurs before and after the main valve 5, and when this exceeds a specified value, the valve seat member 7
The piston 17 operates (moves to the right) due to the pressure difference between the hydraulic pressure transmitted to the upstream hydraulic pressure chamber 21 via the second throttle 20 formed in the hydraulic pressure chamber 11 and the hydraulic pressure chambers 11 and 12. When the right end of the piston 17 contacts the wall surface of the fixed core 18, the switching valve 10 switches to the throttled state.

【０００６】その後、主弁５が開状態になると、主液圧
流路Ｉのブレーキ液は主弁５を通過し、絞り状態の切換
弁１０を介して主液圧流路IIを通って車輪ブレーキに供
給される。切換弁１０の絞り状態により、ブレーキ液の
液圧の脈動を防止することができる。それと共に、主液
圧流路Ｉと主液圧流路IIの液圧差が戻しバネ２２のバネ
力より小さくなると、このバネ力によってピストン１７
が左方向へ移動し、リセット位置に戻り、切換弁１０が
開状態に切換わる。Thereafter, when the main valve 5 is opened, the brake fluid in the main hydraulic pressure flow path I passes through the main valve 5 and passes through the main hydraulic pressure flow path II through the throttled switching valve 10 to the wheel brake. Supplied. The pulsation of the hydraulic pressure of the brake fluid can be prevented by the throttled state of the switching valve 10. At the same time, when the hydraulic pressure difference between the main hydraulic pressure channel I and the main hydraulic pressure channel II becomes smaller than the spring force of the return spring 22, the piston force
Moves to the left, returns to the reset position, and the switching valve 10 switches to the open state.

【０００７】第１絞り２３は、ブレーキ動作中の主弁５
前後の圧力差を減少するように働き、第５絞り２４は、
第１絞り２３の働きに加えて、通常ブレーキ作動時の車
輪ブレーキへのブレーキ液圧の増圧比を決定し、第２絞
り２０はピストン１７の動作を緩慢にするように働き、
また第４絞り２５はピストン１７の逆方向の力を付与す
るように働く。これら絞りにより、ブレーキが急作動し
ても、ピストン１７が主液圧流路を閉じることを防止す
る。ブレーキリリース時には、ブレーキ液は、ピストン
１７の作動の有無にかかわらず、逆流路２６とチェック
弁２７を介して第２液圧流路１４から第１液圧流路２に
流出する。[0007] The first throttle 23 is provided with the main valve 5 during the braking operation.
Working to reduce the pressure difference before and after, the fifth throttle 24
In addition to the function of the first throttle 23, the pressure increase ratio of the brake fluid pressure to the wheel brake during normal brake operation is determined, and the second throttle 20 functions to slow down the operation of the piston 17,
The fourth throttle 25 works so as to apply a force in the opposite direction of the piston 17. These throttles prevent the piston 17 from closing the main hydraulic pressure passage even when the brake is actuated suddenly. When the brake is released, the brake fluid flows out of the second hydraulic passage 14 to the first hydraulic passage 2 via the reverse passage 26 and the check valve 27 regardless of whether the piston 17 is operated.

【０００８】[0008]

【発明が解決しようとする課題】しかしながら、従来例
の常開型電磁弁１の構造では、上流側液圧室２１に液損
がなく、マスタシリンダからの液圧は、第２絞り２０を
介して上流側液圧室２１に加わる。したがって、マスタ
シリンダの急踏み込み時のようにマスタシリンダからの
液圧が急激に上昇する場合に、それに伴って上流側液圧
室２１内の液圧も瞬時に昇圧してピストン１７が移動し
てしまうという誤動作を防止するために、第２絞り２０
の開口面積を微小にしておく必要がある。このため、ア
ンチスキッド制御において主弁５が閉状態になって第１
液圧室４内の液圧が十分に高くなっても、第２絞り２０
が狭いために上流側液圧室２１内の液圧の上昇が鈍くな
り、反応の良い切換動作が行われないという課題があ
る。However, in the structure of the normally-open solenoid valve 1 of the conventional example, there is no liquid loss in the upstream hydraulic chamber 21, and the hydraulic pressure from the master cylinder passes through the second throttle 20. And joins the upstream hydraulic chamber 21. Therefore, when the hydraulic pressure from the master cylinder suddenly increases, such as when the master cylinder is suddenly depressed, the hydraulic pressure in the upstream hydraulic chamber 21 is also instantaneously increased and the piston 17 moves. In order to prevent the erroneous operation of
It is necessary to keep the opening area of the device small. For this reason, in the anti-skid control, the main valve 5 is closed and the first valve 5 is closed.
Even if the hydraulic pressure in the hydraulic chamber 4 becomes sufficiently high, the second throttle 20
Is small, the rise of the hydraulic pressure in the upstream hydraulic chamber 21 becomes slow, and there is a problem that a switching operation with good reaction is not performed.

【０００９】また、ピストン１７のマスタシリンダから
の液圧を受ける上流側液圧室２１の受圧面の面積（シー
ル部材２８が配置された筒状の弁座部材７の外周面とピ
ストン１７の図中の左端が進入するハウジング主体２９
の内周面との間で形成されるリング状空間の面積）と、
ピストン１７の車輪ブレーキからの液圧を受ける下流側
液圧室１１の受圧面の面積（下流側液圧室１１に面する
ピストン１７の左端の面積）とが略同じであるため、上
述したマスタシリンダの急踏み込み時にピストン１７が
誤って移動しないように、またアンチロック動作終了時
に切換弁１０が絞り状態から開状態に速やかに移行する
ように、ピストン１７を常時付勢する戻しバネ２２の弾
性力を強くする必要があり、液圧室１１，１２の差圧
（復帰差圧）が比較的大きいときに切換弁１０が非作動
状態に戻ってしまい、制御性が悪くなるという課題があ
る。また、上流側液圧室２１内にあってピストン１７の
マスタシリンダからの液圧を受けてピストン１７と共に
移動するシール部材２８は、断面円形のＯリングである
ため、摺動抵抗が大きく、切換弁１０の切換動作が遅く
なる、つまり応答が鈍くなるという課題もある。Further, the area of the pressure receiving surface of the upstream hydraulic chamber 21 which receives the hydraulic pressure from the master cylinder of the piston 17 (the outer peripheral surface of the cylindrical valve seat member 7 in which the seal member 28 is disposed and the piston 17) are shown. Housing main body 29 into which the left end enters
Area of the ring-shaped space formed between the inner peripheral surface of
Since the area of the pressure receiving surface of the downstream hydraulic chamber 11 that receives the hydraulic pressure from the wheel brake of the piston 17 (the area of the left end of the piston 17 facing the downstream hydraulic chamber 11) is substantially the same, the master described above is used. The elasticity of the return spring 22 that constantly urges the piston 17 so that the piston 17 does not accidentally move when the cylinder is suddenly depressed and that the switching valve 10 quickly shifts from the throttled state to the open state at the end of the antilock operation. When the pressure difference between the hydraulic pressure chambers 11 and 12 (return pressure difference) is relatively large, the switching valve 10 returns to the non-operating state, and there is a problem that the controllability is deteriorated. Further, the seal member 28 in the upstream hydraulic chamber 21 which moves together with the piston 17 by receiving the hydraulic pressure from the master cylinder of the piston 17 is an O-ring having a circular cross section. There is also a problem that the switching operation of the valve 10 becomes slow, that is, the response becomes slow.

【００１０】したがって、本発明は上記課題を解決すべ
くなされ、その目的とするところは、マスタシリンダの
急踏み込み時における切換弁の誤動作の可能性がなく、
またアンチスキッド制御等の切換弁の復帰差圧を小さく
した常開型電磁弁を提供することにある。Accordingly, the present invention has been made to solve the above-mentioned problem, and an object of the present invention is to eliminate the possibility of a malfunction of the switching valve when the master cylinder is suddenly depressed.
Another object of the present invention is to provide a normally-open solenoid valve in which the return differential pressure of a switching valve for anti-skid control or the like is reduced.

【００１１】[0011]

【課題を解決するための手段】本発明は上記目的を達成
するため次の構成を備える。すなわち、本発明に係る常
開型電磁弁は、マスタシリンダと車輪ブレーキとの間の
主液圧流路に介装され、弁座部材に形成された弁孔に電
磁駆動される弁軸に設けられた弁体が接離動することに
よって前記主液圧流路を非連通または連通の状態にする
主弁と、該主弁と直列に主液圧流路に介装され、マスタ
シリンダ側と車輪ブレーキ側の主液圧流路の液圧差によ
り、開状態と絞り状態の間で切換わる切換弁とを有する
常開型電磁弁において、一端側が電磁石の固定コアに形
成され、内部には該一端側から他端側に貫通すると共に
一端側から他端側に向けて順番に、前記弁軸が摺動自在
に装着される第１領域、該第１領域の内径よりも内径が
大径な第２領域および該第２領域の内径よりも内径が大
径な第３領域に区分けされる貫通孔が形成されたハウジ
ング主体を具備し、前記弁軸は、内部に軸線に沿って連
通孔が形成されると共に、前記第３領域に突出する先端
が前記弁体に形成され、前記弁座部材は、前記ハウジン
グ主体の他端側に取り付けられ、中心には前記貫通孔を
前記マスタシリンダ側の主液圧流路に連通させる前記弁
孔が形成され、前記切換弁は、前記貫通孔の前記第３領
域内に配置され、中心に前記弁軸が挿通する第２弁孔が
形成された第２弁座部材と、外形が筒状に形成されると
共に、前記貫通孔の前記第３領域内に、外周面が第３領
域の内面に接触し、かつ前記弁軸が挿通された状態で前
記ハウジング主体の長手方向に沿って摺動自在に配置さ
れ、一端側の外径および内径が他端側よりも小径に形成
されて該一端側が貫通孔の前記第２領域内に進入し、前
記他端側が前記第２弁座部材と接離するピストンとを有
し、前記弁軸の前記連通孔を経由して前記マスタシリン
ダ側の主液圧流路に連通する前記第２領域内に位置して
マスタシリンダ側の主液圧流路から前記ピストンを前記
第２弁座部材方向へ移動させる接近力を受けるピストン
の前記一端側の受圧面積は、切換弁および前記主弁が共
に開状態の際にマスタシリンダ側の主液圧流路からピス
トンを第２弁座部材から離反させる方向へ移動させる離
反力を受けるピストンの受圧面積よりも小さく、かつ切
換弁が絞り状態にあって主弁が開状態の際にマスタシリ
ンダ側の主液圧流路からピストンが受ける前記離反力の
受圧面積よりも大きいことを特徴とする。The present invention has the following arrangement to achieve the above object. That is, the normally-open solenoid valve according to the present invention is provided on the valve shaft that is interposed in the main hydraulic pressure passage between the master cylinder and the wheel brake and is electromagnetically driven by a valve hole formed in the valve seat member. A main valve that brings the main hydraulic pressure flow path into a non-communication or communication state by the valve body moving toward and away from the main hydraulic pressure flow path; A normally open solenoid valve having a switching valve that switches between an open state and a throttled state due to a hydraulic pressure difference of the main hydraulic pressure flow path of the main hydraulic pressure flow path, one end of which is formed in a fixed core of the electromagnet, and the other end is internally provided from the one end. A first region through which the valve shaft is slidably mounted, in order from the one end to the other end, a second region having an inner diameter larger than the inner diameter of the first region, and A through-hole is formed which is divided into a third region having an inner diameter larger than the inner diameter of the second region. The valve shaft includes a communication hole formed therein along an axis line, and a distal end protruding into the third region is formed in the valve body, and the valve seat member includes a housing main body. The valve hole is formed at the center thereof and communicates the through hole with the main hydraulic pressure flow path on the master cylinder side at the center, and the switching valve is disposed in the third region of the through hole. A second valve seat member in which a second valve hole through which the valve shaft is inserted is formed at the center, and an outer shape is formed in a cylindrical shape, and an outer peripheral surface is formed in the third region of the through hole. It is arranged slidably along the longitudinal direction of the housing main body in a state in which the inner surface of the three regions is in contact and the valve shaft is inserted, and the outer diameter and inner diameter at one end are smaller than those at the other end. The one end enters the second region of the through hole, and the other end A master cylinder having a piston that comes into contact with and separates from the second valve seat member, and is located in the second region that communicates with the main hydraulic pressure flow path on the master cylinder side through the communication hole of the valve shaft; The pressure receiving area on one end side of the piston which receives an approaching force for moving the piston from the main hydraulic pressure flow path toward the second valve seat member is closer to the master cylinder when both the switching valve and the main valve are open. When the switching valve is in the throttled state and the main valve is in the open state, the master pressure is lower than the pressure receiving area of the piston which receives a separating force for moving the piston from the main hydraulic pressure flow path in the direction of separating the piston from the second valve seat member. It is characterized by being larger than the pressure receiving area of the separating force received by the piston from the main hydraulic pressure flow path on the cylinder side.

【００１２】これによれば、第２領域内に位置してマス
タシリンダ側の主液圧流路からピストンを第２弁座部材
方向へ移動させる接近力を受けるピストンの一端側の受
圧面積が、切換弁および主弁が共に開状態の際にマスタ
シリンダ側の主液圧流路からピストンを第２弁座部材か
ら離反させる方向へ移動させる離反力を受けるピストン
の受圧面積よりも小さいから、主弁と切換弁とが共に開
状態にある通常ブレーキ動作時においてマスタシリンダ
の急踏み込み時にも、誤ってピストンが第２弁座部材側
へ移動して絞り状態になることはない。従って、ピスト
ンを絞り状態から開状態に戻すための戻しバネが一般的
に常開型電磁弁には使用されているが、この戻しバネの
付勢力を従来に比べて非常に弱くすることが可能とな
り、結果として切換弁の絞り状態への移行が迅速にな
り、切換弁の応答性が向上する。また、戻しバネの付勢
力を従来に比べて非常に弱くすることが可能であるか
ら、復帰差圧を小さくすることができ、切換弁の動作反
応が緩やかになり、切換弁を絞り状態に維持できるか
ら、アンチロック制御の制御性が向上する。特に、路面
の摩擦係数が低い場合に、車輪ブレーキ側の液圧変化が
非常に小さいので、復帰差圧を小さくすることによっ
て、制御性が良好になる。According to this, the pressure receiving area on one end side of the piston, which is located in the second area and receives an approaching force for moving the piston toward the second valve seat member from the main hydraulic pressure flow path on the master cylinder side, is switched. When the valve and the main valve are both open, the piston is smaller than the pressure receiving area of the piston that receives the separating force that moves the piston from the main hydraulic pressure flow path on the master cylinder side in the direction that separates the piston from the second valve seat member. Even when the master cylinder is suddenly depressed during the normal brake operation in which both the switching valve and the switching valve are in the open state, the piston does not erroneously move toward the second valve seat member to be in the throttled state. Therefore, although a return spring for returning the piston from the throttled state to the open state is generally used for a normally-open solenoid valve, the biasing force of this return spring can be made much weaker than before. As a result, the shift of the switching valve to the throttled state is quickened, and the responsiveness of the switching valve is improved. Also, since the urging force of the return spring can be made very weaker than before, the return differential pressure can be reduced, the operation response of the switching valve becomes gentle, and the switching valve is maintained in the throttled state. Therefore, the controllability of the antilock control is improved. In particular, when the friction coefficient of the road surface is low, the change in hydraulic pressure on the wheel brake side is very small. Therefore, the controllability is improved by reducing the return differential pressure.

【００１３】また、前記ピストンの前記第２弁座部材と
当接する他端側の端面には、環状の凸部が形成されてい
ると、ピストンの他端側が第２弁座部材と当接してシー
ルする部位の径が凸部の径となり、上述した各受圧面積
がばらつかなくなり、アンチロック動作から通常ブレー
キ動作へ移行する復帰差圧（ピストンが開状態へ移行す
る際のマスタシリンダ側の主液圧流路Ｉの液圧と車輪ブ
レーキ側の主液圧流路IIの液圧との圧力差）が略一定と
なり、制動フィーリングが良好になる。また、シール性
も向上する。前記凸部は、具体的には前記ピストンの他
端側の端面の内周縁若しくは外周縁に形成される。より
確実に凸部が第２弁座部材に最初に当接できるようにす
るためである。[0013] Further, if an annular convex portion is formed on the other end surface of the piston that contacts the second valve seat member, the other end of the piston contacts the second valve seat member. The diameter of the part to be sealed becomes the diameter of the convex part, and the above-mentioned pressure receiving areas do not vary, and the return differential pressure at which the anti-lock operation shifts to the normal braking operation (the main cylinder side when the piston shifts to the open state) The pressure difference between the hydraulic pressure in the hydraulic pressure channel I and the hydraulic pressure in the main hydraulic pressure channel II on the wheel brake side becomes substantially constant, and the braking feeling is improved. Further, the sealing property is also improved. The protrusion is specifically formed on an inner peripheral edge or an outer peripheral edge of an end face on the other end side of the piston. This is to ensure that the projection can first come into contact with the second valve seat member more reliably.

【００１４】また、前記ハウジング主体の前記第２領域
には、前記弁軸の外周面と第２領域の内周面との間をシ
ールして前記マスタシリンダ側の主液圧流路からの液圧
を前記ピストンに伝える断面Ｖ字状の一方向性シール部
材が、弁軸に外嵌された状態で配置されている構成とす
ると、ピストンと共に移動する際に、貫通孔の第２領域
の内周面と弁軸の外周面とから受ける摩擦力が、従来の
Ｏリングの場合に比べて小さくなり、切換弁の応答性が
向上する。In the second region mainly of the housing, a seal is provided between an outer peripheral surface of the valve shaft and an inner peripheral surface of the second region so that hydraulic pressure from the main hydraulic passage on the master cylinder side can be reduced. When the one-way sealing member having a V-shaped cross-section for transmitting the pressure to the piston is arranged so as to be fitted on the valve shaft, the inner periphery of the second region of the through hole when the piston moves together with the piston. The frictional force received from the surface and the outer peripheral surface of the valve shaft is smaller than that of the conventional O-ring, and the responsiveness of the switching valve is improved.

【００１５】[0015]

【発明の実施の形態】以下、本発明に係る常開型電磁弁
の一実施の形態について添付図面を基に説明する。ま
ず、常開型電磁弁が使用される車両用アンチロックブレ
ーキ装置（以下、単にＡＢＳ装置）の概略構成について
図５を用いて説明する。各車輪には、左前輪用車輪ブレ
ーキＢｆｌ、右後輪用車輪ブレーキＢｒｒ、右前輪用車
輪ブレーキＢｆｒ、左後輪用車輪ブレーキＢｒｌが配置
されている。また、一対のＭ／Ｃはタンデム型マスタシ
リンダを構成し、図示しないブレーキペダルの踏み込み
に応じた制動液圧を出力する。ブレーキ液圧制御装置１
００は、上述した４つのブレーキＢｆｌ，Ｂｒｒ，Ｂｆ
ｒ，Ｂｒｌとタンデム型マスタシリンダＭ／Ｃとの間
に、ブレーキＢｆｌ，Ｂｒｒ，Ｂｆｒ，Ｂｒｌとは主液
圧流路IIを介して、またマスタシリンダＭ／Ｃとは主液
圧流路Ｉを介して接続された状態で介設される。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a normally-open solenoid valve according to the present invention will be described below with reference to the accompanying drawings. First, a schematic configuration of a vehicle anti-lock brake device (hereinafter simply referred to as an ABS device) using a normally-open solenoid valve will be described with reference to FIG. On each wheel, a left front wheel brake Bfl, a right rear wheel brake Brr, a right front wheel brake Bfr, and a left rear wheel brake Brl are arranged. The pair of M / Cs constitute a tandem type master cylinder, and outputs a brake fluid pressure according to the depression of a brake pedal (not shown). Brake fluid pressure control device 1
00 is the four brakes Bfl, Brr, Bf described above.
Between the r and Brl and the tandem master cylinder M / C, the brakes Bfl, Brr, Bfr and Brl are connected via a main hydraulic passage II, and the master cylinder M / C is connected via a main hydraulic passage I. It is interposed in a connected state.

【００１６】さらにブレーキ液圧制御装置１００の構成
について詳細に説明する。ブレーキ液圧制御装置１００
は、左前輪用車輪ブレーキＢｆｌ、右後輪用車輪ブレー
キＢｒｒ、右前輪用車輪ブレーキＢｆｒおよび左後輪用
車輪ブレーキＢｒｌに個別に対応した４つの弁手段とし
ての常開型電磁弁Ｖｏｆｌ，Ｖｏｒｒ，Ｖｏｆｒ，Ｖｏ
ｒｌと、各常開型電磁弁Ｖｏｆｌ〜Ｖｏｒｌにそれぞれ
並列に接続され、マスタシリンダＭ／Ｃへの入力を解除
した際に開弁して、対応する車輪ブレーキＢｆｌ〜Ｂｒ
ｌから該マスタシリンダＭ／Ｃへブレーキ液を戻す４つ
のチェック弁Ｃｏｆｌ，Ｃｏｒｒ，Ｃｏｆｒ，Ｃｏｒｌ
と、各車輪ブレーキＢｆｌ〜Ｂｒｌに個別に対応した４
つの常閉型電磁弁Ｖｃｆｌ，Ｖｃｒｒ，Ｖｃｆｒ，Ｖｃ
ｒｌと、左前輪用車輪ブレーキＢｆｌおよび右後輪用車
輪ブレーキＢｒｒ側ならびに右前輪用車輪ブレーキＢｆ
ｒおよび左後輪用車輪ブレーキＢｒｌ側にそれぞれ個別
に対応した一対のリザーバＲａ，Ｒｂと、両リザーバＲ
ａ，Ｒｂに接続される一対の往復動型プランジャポンプ
Ｐａ，Ｐｂと、これらを連通させる複数の液圧流路とを
備え、これらは外形がブロック状に形成された一つの金
属製の基体（不図示）内に収容されている。Further, the configuration of the brake fluid pressure control device 100 will be described in detail. Brake fluid pressure control device 100
Are normally open solenoid valves Vofl and Vorr as four valve means individually corresponding to the left front wheel brake Bfl, the right rear wheel brake Brr, the right front wheel brake Bfr, and the left rear wheel brake Brl. , Vofr, Vo
rl and the normally-open solenoid valves Vofl to Vorl, respectively, are opened in parallel when the input to the master cylinder M / C is released, and the corresponding wheel brakes Bfl to Br are opened.
1 to return the brake fluid from the master cylinder M / C to the four check valves Cofl, Corr, Cofr, and Corl.
And 4 individually corresponding to each wheel brake Bfl-Brl.
Normally closed solenoid valves Vcfl, Vcrr, Vcfr, Vc
rl, the left front wheel brake Bfl, the right rear wheel brake Brr side, and the right front wheel brake Bf
r and a pair of reservoirs Ra and Rb respectively corresponding to the left and right rear wheel brakes Brl, and both reservoirs R
a, Rb, and a pair of reciprocating plunger pumps Pa, Pb, and a plurality of hydraulic passages for communicating the plunger pumps Pa, Pb. (Shown).

【００１７】また、ブレーキ液圧制御装置１００は、両
プランジャポンプＰａ，Ｐｂに共通な単一のブレーキ液
圧制御装置用モータ（以下、単にモータ）Ｍを有し、こ
のモータＭは、一対のプランジャポンプＰａ，Ｐｂを駆
動する。また、各常開型電磁弁Ｖｏｆｌ〜Ｖｏｒｌおよ
び各常閉型電磁弁Ｖｃｆｌ〜Ｖｃｒｌの消磁・励磁を切
り換え制御する電子制御ユニットＥＣＵも有する。ま
た、電子制御ユニットＥＣＵは、各車輪に設けられた車
輪速度センサ（図示せず）などから車両の走行状態が入
力されるようになっている。電子制御ユニットＥＣＵ
は、各々の車輪ブレーキＢｆｌ〜Ｂｒｌ毎に車両の走行
状態に応じて、各々の常開型電磁弁Ｖｏｆｌ〜Ｖｏｒｌ
の内、該当車輪に対応するいずれかを消磁・開弁し、各
々の常閉型電磁弁Ｖｃｆｌ〜Ｖｃｒｌの内、該当車輪に
対応するいずれかを消磁・閉弁してマスタシリンダＭ／
Ｃからホイールシリンダ（図示せず）に加わる液圧によ
って制動トルクを増加させる増圧モード、各々の常開型
電磁弁Ｖｏｆｌ〜Ｖｏｒｌの内、該当車輪に対応するい
ずれかを励磁・閉弁し、各々の常閉型電磁弁Ｖｃｆｌ〜
Ｖｃｒｌの内、該当車輪に対応するいずれかを消磁・閉
弁してマスタシリンダＭ／Ｃからホイールシリンダ（図
示せず）に液圧を伝わらないようにして制動トルクを保
持する保持モード、各々の常開型電磁弁Ｖｏｆｌ〜Ｖｏ
ｒｌの内、該当車輪に対応するいずれかを励磁・閉弁
し、各々の常閉型電磁弁Ｖｃｆｌ〜Ｖｃｒｌの内、該当
車輪に対応するいずれかを励磁・開弁してホイールシリ
ンダ（図示せず）からリザーバＲａ，Ｒｂにブレーキ液
を一時的に貯留することで、車輪がロック状態にならな
いように制動トルクを減少させる減圧モードのいずれか
の指令により制御している。そして、電子制御ユニット
ＥＣＵはモータＭを駆動させて、ポンプＰａ，Ｐｂを駆
動させてリザーバＲａ，Ｒｂに一時貯留したブレーキ液
をマスタシリンダＭ／Ｃ側に戻すようになっている。The brake fluid pressure control device 100 has a single brake fluid pressure control device motor (hereinafter simply referred to as a motor) M which is common to both plunger pumps Pa and Pb. The plunger pumps Pa and Pb are driven. The electronic control unit ECU also controls the switching between demagnetization and excitation of each of the normally-open solenoid valves Vofl to Vorl and each of the normally-closed solenoid valves Vcfl to Vcrl. Further, the electronic control unit ECU is configured to input a traveling state of the vehicle from a wheel speed sensor (not shown) provided on each wheel. Electronic control unit ECU
Are normally open solenoid valves Vofl-Vorl according to the running state of the vehicle for each wheel brake Bfl-Brl.
Of the normally closed solenoid valves Vcfl to Vcrl, and demagnetizes and closes one of the normally closed solenoid valves Vcfl to Vcrl corresponding to the corresponding wheel.
C: a pressure-increasing mode in which the braking torque is increased by a hydraulic pressure applied to a wheel cylinder (not shown) from C, and among the normally open solenoid valves Vofl to Vorl, one of the solenoid valves corresponding to the corresponding wheel is excited and closed, Each normally closed solenoid valve Vcfl ~
A holding mode for holding the braking torque by demagnetizing / closing one of the Vcrls corresponding to the corresponding wheel so as not to transmit the hydraulic pressure from the master cylinder M / C to the wheel cylinder (not shown). Normally open solenoid valve Vofl to Vo
rl, one of the normally closed solenoid valves Vcfl to Vcrl is excited and opened, and one of the normally closed solenoid valves Vcfl to Vcrl is excited and opened to open a wheel cylinder (not shown). 3), the brake fluid is temporarily stored in the reservoirs Ra and Rb, and the brake fluid is controlled by any one of the pressure reduction mode commands to reduce the braking torque so that the wheels are not locked. Then, the electronic control unit ECU drives the motor M, drives the pumps Pa and Pb, and returns the brake fluid temporarily stored in the reservoirs Ra and Rb to the master cylinder M / C side.

【００１８】次に、本実施の形態の常開型電磁弁３０の
構造について図１を用いて説明する。なお、従来例と同
じ構成については同じ符号を付し、詳細な説明は省略す
る。ハウジング主体３１は、磁性金属により段付の円筒
状に形成されている。この鍔状の段部３２はハウジング
主体３１の中途部分に形成されており、段部３２を挟ん
で一端側（図１中の右端側）が電磁石１５の固定コア１
８に形成されている。ハウジング主体３１の内部には、
一端側から他端側（図１中の左端側）に貫通する貫通孔
３３が形成されている。そして、貫通孔３３は、一端側
から他端側に向けて順番に、弁軸３４が摺動自在に装着
される第１領域Ｋ１、第１領域Ｋ１の内径よりも内径が
大径な第２領域Ｋ２（内径Ａ）および第２領域Ｋ２の内
径Ａよりも内径が大径な第３領域Ｋ３（内径Ｂ）に区分
けされる。ハウジング主体３１の他端側（図１中の左端
側）には、主液圧流路Ｉと主液圧流路IIとを連通させる
と共に、車輪ブレーキへのブレーキ液の流量を調節する
第１オリフィス３５が形成されている。また、この他端
側には、後述するピストンに対する背圧抜き孔４９も形
成されている。そして第１オリフィス３５と背圧抜き孔
４９は共に、貫通孔３３の第３領域Ｋ３に形成され、特
に背圧抜き孔４９は第１オリフィス３５よりも第２領域
Ｋ２寄りに設けられている。Next, the structure of the normally-open solenoid valve 30 of the present embodiment will be described with reference to FIG. The same components as those of the conventional example are denoted by the same reference numerals, and detailed description thereof will be omitted. The housing main body 31 is formed in a stepped cylindrical shape from a magnetic metal. This flange-shaped step 32 is formed in the middle of the housing main body 31, and one end (the right end in FIG. 1) of the fixed core 1 of the electromagnet 15 with the step 32 interposed therebetween.
8 is formed. Inside the housing main body 31,
A through hole 33 penetrating from one end to the other end (the left end in FIG. 1) is formed. The through-hole 33 is formed in order from the one end side to the other end side in the first region K1 where the valve shaft 34 is slidably mounted, and the second region having an inner diameter larger than the inner diameter of the first region K1. It is divided into a region K2 (inner diameter A) and a third region K3 (inner diameter B) having an inner diameter larger than the inner diameter A of the second region K2. A first orifice 35 is provided at the other end (left end in FIG. 1) of the housing main body 31 to connect the main hydraulic pressure flow path I and the main hydraulic pressure flow path II and to adjust the flow rate of brake fluid to the wheel brakes. Are formed. Further, on the other end side, a back pressure release hole 49 for a piston described later is also formed. The first orifice 35 and the back pressure release hole 49 are both formed in the third region K3 of the through hole 33. In particular, the back pressure release hole 49 is provided closer to the second region K2 than the first orifice 35.

【００１９】弁軸３４は非磁性材料を用いて外径が一定
（直径Ｃ）の筒体に形成され、内部に軸線に沿って両端
部に開口する連通孔３６が形成されている。弁軸３４の
一端側（図１中の右端側）はハウジング主体３１の一端
側から突出して可動コア１６に当接し、他端側（図１中
の左端側）はハウジング主体３１の第３領域Ｋ３内に位
置している。また、弁軸３４の他端側は、その内径が他
の部位の内径よりも若干大径となって肉薄に形成され、
主弁５を構成する弁体３４ａに形成されている。The valve shaft 34 is formed of a non-magnetic material into a cylindrical body having a constant outer diameter (diameter C), and has communication holes 36 opened at both ends along the axis. One end (the right end in FIG. 1) of the valve shaft 34 projects from one end of the housing main body 31 and abuts on the movable core 16, and the other end (the left end in FIG. 1) is the third region of the housing main body 31. It is located in K3. In addition, the other end of the valve shaft 34 is formed to be thin with its inner diameter being slightly larger than the inner diameters of other parts,
It is formed on a valve body 34 a constituting the main valve 5.

【００２０】ガイド筒３７は、非磁性材料、例えばステ
ンレス鋼により先端を半球状の閉塞端とした薄肉の有底
円筒状に形成されている。ガイド筒３７は、その開口端
側が固定コア１８に、例えば溶接等により結合されてい
る。そしてハウジング主体３１は、車両用ブレーキ制御
装置を構成する基体３８に形成された電磁弁用の嵌合孔
３９内に、他端側が嵌め込まれて固定されるが、ハウジ
ング主体３１が嵌合孔３９内へ嵌め込まれ、固定された
状態では、ガイド筒３７は嵌合孔３９から突出する状態
となる。なお、嵌合孔３９の底面には、主液圧流路Ｉに
連通する第１液圧流路２が開口し、また嵌合孔３９の内
周面には主液圧流路IIに連通する第２液圧流路１４が開
口している。The guide cylinder 37 is made of a nonmagnetic material, for example, stainless steel, and has a thin bottomed cylindrical shape with a hemispherical closed end. The guide cylinder 37 has its open end connected to the fixed core 18 by, for example, welding. The housing main body 31 is fixed by fitting the other end into a fitting hole 39 for an electromagnetic valve formed in a base body 38 constituting a vehicle brake control device. In a state where the guide cylinder 37 is fitted and fixed inside, the guide cylinder 37 projects from the fitting hole 39. A first hydraulic pressure channel 2 communicating with the main hydraulic pressure channel I is opened on the bottom surface of the fitting hole 39, and a second hydraulic pressure channel 2 communicating with the main hydraulic pressure channel II is formed on the inner peripheral surface of the fitting hole 39. The hydraulic passage 14 is open.

【００２１】ガイド筒３７内には、電磁石１５で駆動さ
れる可動コア１６が摺動可能に配置されている。可動コ
ア１６の弁軸３４と当接する端面には、弁軸３４の連通
孔３６を、ガイド筒３７の内部および弁軸３４の外周面
とハウジング主体３１の貫通孔３３の内周面との間で形
成される流路、さらには弁軸３４の外方の貫通孔３３の
第２領域Ｋ２に連通させるための凹溝４０が形成されて
いる。また、ハウジング主体３１の段部３２にはＯリン
グを用いて構成された第１シール部材４１が外嵌され、
段部３２の外周面と嵌合孔３９の内周面とを液密にシー
ルする。The movable core 16 driven by the electromagnet 15 is slidably disposed in the guide cylinder 37. A communication hole 36 of the valve shaft 34 is formed on an end surface of the movable core 16 which abuts on the valve shaft 34, between the inside of the guide cylinder 37 and the outer peripheral surface of the valve shaft 34 and the inner peripheral surface of the through hole 33 of the housing main body 31. Are formed, and a concave groove 40 for communicating with the second region K2 of the through hole 33 outside the valve shaft 34 is formed. In addition, a first seal member 41 configured using an O-ring is externally fitted to the step portion 32 of the housing main body 31,
The outer peripheral surface of the step portion 32 and the inner peripheral surface of the fitting hole 39 are liquid-tightly sealed.

【００２２】ハウジング主体３１の他端側には、カップ
状部材４２が、その底面側から貫通孔３３に挿入されて
固定されている。カップ状部材４２の底面には弁体３４
ａに形成された弁軸３４の先端が挿通可能な第１軸用孔
４２ａが形成されると共に、内底面には中心に弁孔６が
設けられて外形がリング状に形成された弁座部材４４
が、カップ状部材４２の内周面に取り付けられたリング
状の支持金具４５とカップ状部材４２の内底面との間で
挟まれた状態で固定されている。この弁孔６とカップ状
部材４２の底面に形成された第１軸用孔４２ａとは同軸
に配置される。そして、この弁座部材４４に弁軸３４の
先端に形成された弁体３４ａが当接することによって、
主弁５が閉状態になり、離反すると主弁５が閉状態とな
る。On the other end side of the housing main body 31, a cup-shaped member 42 is inserted into the through hole 33 from the bottom side thereof and fixed. The valve body 34 is provided on the bottom surface of the cup-shaped member 42.
a first shaft hole 42a through which the tip of the valve shaft 34 formed in the valve shaft 34a can be inserted, and a valve hole 6 provided in the center on the inner bottom surface to form a ring-shaped valve seat member. 44
Are fixed between the ring-shaped support member 45 attached to the inner peripheral surface of the cup-shaped member 42 and the inner bottom surface of the cup-shaped member 42. The valve hole 6 and the first shaft hole 42a formed on the bottom surface of the cup-shaped member 42 are arranged coaxially. When the valve body 34a formed at the tip of the valve shaft 34 contacts the valve seat member 44,
The main valve 5 is closed, and when separated, the main valve 5 is closed.

【００２３】また、支持金具４５の内周側には中心側に
向けて延出する第１支持片４５ａが形成され、この第１
支持片４５ａと、弁軸３４の先端側が肉薄に形成される
ことによって主弁５の内周面に構成された第１段差部３
４ｂとの間には、弁軸３４側の端部が弁軸３４の内部に
収納される形で弁軸用バネ４６が縮長した状態で配置さ
れており、弁軸３４を弁座部材４４から常時離反する方
向へ弾発付勢している。A first support piece 45a extending toward the center is formed on the inner peripheral side of the support fitting 45.
The first step portion 3 formed on the inner peripheral surface of the main valve 5 by forming the support piece 45a and the distal end side of the valve shaft 34 to be thin.
4b, the valve shaft spring 46 is contracted and arranged such that the end on the valve shaft 34 side is housed inside the valve shaft 34, and the valve shaft 34 is connected to the valve seat member 44. It is always urged to move away from it.

【００２４】また、カップ状部材４２の開口側（図１の
左側）は貫通孔３３から突出しており、その突出する外
周面に嵌合孔３９の内周面と摺動自在に接触するリブ部
４２ｂが形成されている。そして、このリブ部４２ｂと
ハウジング主体３１の他端側端面との間に挟まれるよう
にして、Ｏリングを用いて構成された第２シール部材４
３がカップ状部材４２に外嵌された状態で配置されてい
る。この第２シール部材４３によって嵌合孔３９の内周
面とカップ状部材４２の外周面との間が液密にシールさ
れて、カップ状部材４２の内周面と嵌合孔３９の内周面
との間で、第１液圧流路２に連通する第１液圧室４が構
成される。なお、カップ状部材４２の開口側内周面に
は、第１フィルタ３が固定されている。また、カップ状
部材４２の貫通孔３３への挿入量は、カップ状部材４２
の底面がハウジング主体３１の他端側に設けられた第１
オリフィス３５に達して第１オリフィス３５を閉塞しな
いように設定されている。The opening side (the left side in FIG. 1) of the cup-shaped member 42 protrudes from the through-hole 33, and a rib portion slidably contacting the protruding outer peripheral surface with the inner peripheral surface of the fitting hole 39. 42b is formed. The second seal member 4 formed by using an O-ring so as to be sandwiched between the rib portion 42b and the other end surface of the housing main body 31.
3 is arranged so as to be fitted on the cup-shaped member 42. The gap between the inner peripheral surface of the fitting hole 39 and the outer peripheral surface of the cup-shaped member 42 is liquid-tightly sealed by the second seal member 43, and the inner peripheral surface of the cup-shaped member 42 and the inner peripheral surface of the fitting hole 39 are sealed. A first hydraulic pressure chamber 4 communicating with the first hydraulic pressure flow path 2 is formed between the first hydraulic pressure chamber 2 and the surface. The first filter 3 is fixed to the inner peripheral surface on the opening side of the cup-shaped member 42. The amount of insertion of the cup-shaped member 42 into the through hole 33 is
Is provided at the other end of the housing main body 31.
The first orifice 35 is set so as not to reach the orifice 35 and close the first orifice 35.

【００２５】切換弁１０について説明する。第２弁座部
材４７は、中心に弁軸３４が挿通する第２弁孔４７ａが
形成されて円環状に形成され、貫通孔３３の第３領域Ｋ
３内に配置されている。一例として本実施の形態では、
第２弁座部材４７は、カップ状部材４２の外底面に密着
した状態で、第１オリフィス３５を閉塞しない位置に配
置されている。また、第２弁座部材４７の第２弁孔４７
ａの内周面には、戻しバネ２２の端部と当接して支持す
るための第２支持片４７ｂが延出して設けられている。The switching valve 10 will be described. The second valve seat member 47 is formed in an annular shape with a second valve hole 47 a through which the valve shaft 34 is inserted at the center, and is formed in a third region K of the through hole 33.
3. As an example, in the present embodiment,
The second valve seat member 47 is disposed at a position where the first orifice 35 is not closed in a state of being in close contact with the outer bottom surface of the cup-shaped member 42. Further, the second valve hole 47 of the second valve seat member 47 is provided.
A second support piece 47b for abutting and supporting the end of the return spring 22 is provided on the inner peripheral surface of a.

【００２６】ピストン４８は、外形が筒状（一例として
円筒状）に形成されて貫通孔３３の第３領域Ｋ３と第２
領域Ｋ２内に、その内部に弁軸３４が挿通された状態で
配置されている。このピストン４８はハウジング主体３
１の長手方向（図１中の左右方向）に沿って摺動して第
２弁座部材４７に接離動することで、切換弁１０を開状
態と絞り状態とに切り換える機能を有する。ピストン４
８は、その一端側（図１中の右端側）の外径および内径
が、第３領域Ｋ３内に位置する他端側（図１中の左端
側）よりも小径に形成されて、貫通孔３３の第２領域Ｋ
２内に進入している。ピストン４８は、一例として外径
の大小に着目して、貫通孔３３の第３領域Ｋ３内でのみ
摺動する大径筒部４８ａと、大径筒部４８ａの右端側に
一体的に形成されて、その先端側（右端側）が貫通孔３
３の第２領域Ｋ２内に突出入する小径筒部４８ｂとに区
分けされる。The piston 48 has a cylindrical shape (for example, a cylindrical shape) in its outer shape.
The valve shaft 34 is disposed in the region K2 with the valve shaft 34 inserted therein. This piston 48 is the housing main body 3
1 has a function of switching the switching valve 10 between the open state and the throttle state by sliding along the longitudinal direction (the left-right direction in FIG. 1) and moving toward and away from the second valve seat member 47. Piston 4
8 has an outer diameter and an inner diameter at one end side (the right end side in FIG. 1) smaller than the other end side (the left end side in FIG. 1) located in the third region K3, and has a through hole. 33 second region K
2 has entered. The piston 48 is formed integrally with the large-diameter cylindrical portion 48a that slides only in the third region K3 of the through hole 33 and the right end side of the large-diameter cylindrical portion 48a, paying attention to the size of the outer diameter as an example. And the tip side (right end side)
3 and a small-diameter cylindrical portion 48b protruding into the second region K2.

【００２７】さらに詳細には、大径筒部４８ａの外径
は、貫通孔３３の第３領域Ｋ３内でスムーズに摺動でき
るように第３領域Ｋ３の内径より若干小径に形成され、
内径Ｄは、貫通孔３３の第２領域Ｋ２の内径Ａよりも小
径で、かつ後述する戻しバネ２２が内部に収容できるよ
うに弁軸３４の外周面との間に隙間が生ずる略一定の径
に設定されている。なお、本実施の形態では、内径Ｄは
大径筒部４８ａの内径となる構造であるが、これに限定
されず、例えば戻しバネ２２の長さに対応して小径筒部
４８ｂの領域まで達する構成も考えられるし、また大径
筒部４８ａの中途部分までしか達しない構成も考えられ
る。また、大径筒部４８ａの各端部は、ハウジング主体
３１の第３領域Ｋ３に設けられた第１オリフィス３５と
背圧抜き孔４９の近傍に位置しており、摺動した際でも
第１オリフィス３５や背圧抜き孔４９を閉塞しないよう
に、各端部の外径が大径筒部４８ａの中途部分の外径よ
りもさらに小径に形成されている。これにより、第１オ
リフィス３５側のピストン４８の大径筒部４８ａの外周
面、貫通孔３３の第３領域Ｋ３の内周面および第２弁座
部材４７との間に、ピストン４８に対する下流側液圧室
１１が形成される。また、背圧抜き孔４９側のピストン
４８の大径筒部４８ａの外周面と貫通孔３３の第３領域
Ｋ３の内周面との間に、ピストン４８に対する背圧用液
圧室５０が形成される。More specifically, the outer diameter of the large-diameter cylindrical portion 48a is formed to be slightly smaller than the inner diameter of the third region K3 so that the large-diameter cylindrical portion 48a can slide smoothly in the third region K3 of the through hole 33.
The inner diameter D is smaller than the inner diameter A of the second region K2 of the through-hole 33, and has a substantially constant diameter where a gap is formed between the inner surface A and the outer peripheral surface of the valve shaft 34 so that the return spring 22 described later can be housed therein. Is set to In the present embodiment, the inner diameter D is a structure in which the inner diameter is the inner diameter of the large-diameter cylindrical portion 48a. However, the present invention is not limited to this. For example, the inner diameter D reaches the region of the small-diameter cylindrical portion 48b corresponding to the length of the return spring 22. A configuration is also conceivable, and a configuration that reaches only a middle portion of the large-diameter cylindrical portion 48a is also conceivable. Further, each end of the large-diameter cylindrical portion 48a is located in the vicinity of the first orifice 35 and the back pressure release hole 49 provided in the third region K3 of the housing main body 31, so that even when sliding, the first end is kept. The outer diameter of each end is formed smaller than the outer diameter of the middle part of the large-diameter cylindrical portion 48a so as not to block the orifice 35 and the back pressure release hole 49. Thus, between the outer peripheral surface of the large-diameter cylindrical portion 48a of the piston 48 on the first orifice 35 side, the inner peripheral surface of the third region K3 of the through hole 33, and the second valve seat member 47, the downstream side with respect to the piston 48 A hydraulic chamber 11 is formed. A back pressure hydraulic chamber 50 for the piston 48 is formed between the outer peripheral surface of the large-diameter cylindrical portion 48a of the piston 48 on the side of the back pressure release hole 49 and the inner peripheral surface of the third region K3 of the through hole 33. You.

【００２８】また、小径筒部４８ｂの外径と内径は、貫
通孔３３の第２領域Ｋ２内でスムーズに摺動できるよう
に、外径は第２領域Ｋ２の内径Ａより若干小径に形成さ
れ、内径は弁軸３４の外径Ｃよりも若干大径に形成され
ている。そして、小径筒部４８ｂの先端、貫通孔３３の
第２領域Ｋ２の内周面および弁軸３４の外周面との間
に、ピストン４８に対する上流側液圧室２１が形成され
る。上流側液圧室２１内には、小径筒部４８ｂの先端側
から順番に、摺動抵抗の少ない材料、例えばテフロン等
の樹脂材で形成されたバックアップリング５１と、バッ
クアップリング５１側に屈曲部位が向くように配置され
た断面Ｖ字状の一方向性シール部材（所謂カップシー
ル）５２とが配置されている。この一方向性シール部材
５２には、第１液圧室４、主弁５の弁孔６、弁軸３４の
連通孔３６、可動コア１６の凹溝４０および弁軸３４の
外周面と貫通孔３３の第１領域Ｋ１の内周面との間に形
成される流路を経由してマスタシリンダ側の主液圧流路
Ｉのブレーキ液圧が常時印加されている。そしてバック
アップリング５１は、一方向性シール部材５２が液圧を
受けて変形した際に、小径筒部４８ｂとハウジング主体
３１との間の隙間や小径筒部４８ｂと弁軸３４との間の
隙間に入り込まないようにしている。一方向性シール部
材５２はピストン４８と共に移動するが、その際に貫通
孔３３の第２領域Ｋ２の内周面と弁軸３４の外周面とか
ら受ける摩擦力が、従来のＯリングの場合に比べて小さ
くなり、切換弁１０の応答性が向上する。The outer diameter and the inner diameter of the small-diameter cylindrical portion 48b are slightly smaller than the inner diameter A of the second region K2 so that the small-diameter cylindrical portion 48b can slide smoothly in the second region K2 of the through hole 33. , The inner diameter is slightly larger than the outer diameter C of the valve shaft 34. The upstream hydraulic chamber 21 for the piston 48 is formed between the distal end of the small-diameter cylindrical portion 48b, the inner peripheral surface of the second region K2 of the through hole 33, and the outer peripheral surface of the valve shaft 34. In the upstream hydraulic chamber 21, a backup ring 51 made of a material having low sliding resistance, for example, a resin material such as Teflon, and a bent portion formed on the backup ring 51 side are sequentially arranged from the distal end side of the small-diameter cylindrical portion 48 b. And a one-way sealing member (so-called cup seal) 52 having a V-shaped cross section, which is disposed so as to face. The one-way seal member 52 has a first hydraulic chamber 4, a valve hole 6 of the main valve 5, a communication hole 36 of the valve shaft 34, a concave groove 40 of the movable core 16, and an outer peripheral surface of the valve shaft 34 and a through hole. The brake hydraulic pressure in the main hydraulic pressure flow path I on the master cylinder side is constantly applied via a flow path formed between the main cylinder 33 and the inner peripheral surface of the first region K1. When the one-way seal member 52 is deformed by receiving the hydraulic pressure, the backup ring 51 provides a gap between the small-diameter cylindrical portion 48b and the housing main body 31 and a gap between the small-diameter cylindrical portion 48b and the valve shaft 34. Try not to get in. The one-way seal member 52 moves together with the piston 48. At this time, the frictional force received from the inner peripheral surface of the second region K2 of the through hole 33 and the outer peripheral surface of the valve shaft 34 is smaller than that of a conventional O-ring. In comparison, the responsiveness of the switching valve 10 is improved.

【００２９】また、ピストン４８の、第２弁座部材４７
と当接する他端側の端面（大径筒部４８ａの左端面）に
は、環状の凸部５３が形成されている。本実施の形態で
は、この凸部５３の形成位置は、他端側の端面の内周縁
に沿って形成され（直径が略大径筒部４８ａの内径Ｄと
同じになる）ている。なお、凸部５３は他端側の端面の
外周縁に沿って形成する構成も考えられる。内径Ｄは環
状の凸部５３が描く円の直径である。ここで凸部５３の
概念には、図１に示すようにピストン４８の端面の一部
に局部的に断面Ｕ字状等の凸状部分を形成する構成以外
にも、ピストン４８の他端側の端面の軸線方向に沿った
全体の断面形状を、例えば外周縁側若しくは内周縁側が
鋭角な頂部となる斜面に形成したり、また中央部分が頂
部となるＶ字状に形成する等、第２弁座部材４７と最初
に当接する部位が明確になる構成の全てが含まれるもの
とする。この凸部５３を設けると、ピストン４８の他端
側が第２弁座部材４７と当接してシールする部位の径が
凸部５３の径となり、ピストン４８の後述する各受圧面
積がばらつかなくなり、アンチロック動作から通常ブレ
ーキ動作へ移行する復帰差圧が略一定となり、制動フィ
ーリングが良好になる。また、凸部５３が第２弁座部材
４７にめり込み、シール性も向上する。The second valve seat member 47 of the piston 48
An annular convex portion 53 is formed on the other end surface (the left end surface of the large-diameter cylindrical portion 48a) in contact with the cylindrical member 48a. In the present embodiment, the formation position of the convex portion 53 is formed along the inner peripheral edge of the end face on the other end side (the diameter is substantially the same as the inner diameter D of the large-diameter cylindrical portion 48a). Note that a configuration in which the protrusion 53 is formed along the outer peripheral edge of the end face on the other end side is also conceivable. The inner diameter D is the diameter of a circle drawn by the annular convex portion 53. Here, the concept of the convex portion 53 includes, besides a configuration in which a convex portion such as a U-shaped cross section is locally formed on a part of the end surface of the piston 48 as shown in FIG. The entire cross-sectional shape along the axial direction of the end face is formed on a slope having an acute-angled top on the outer peripheral side or the inner peripheral side, or in a V-shape with the central portion on the top. It is assumed that all of the configurations in which the portion that first comes into contact with the valve seat member 47 becomes clear are included. When the convex portion 53 is provided, the diameter of the portion where the other end of the piston 48 comes into contact with and seals the second valve seat member 47 becomes the diameter of the convex portion 53, and the pressure receiving areas of the piston 48, which will be described later, do not vary. The return differential pressure for shifting from the antilock operation to the normal brake operation becomes substantially constant, and the braking feeling is improved. In addition, the convex portion 53 sinks into the second valve seat member 47, and the sealing performance is also improved.

【００３０】また、ピストン４８の大径筒部４８ａの他
端側（第２弁座部材４７と当接する端部側）には、ピス
トン４８の内周側領域と下流側液圧室１１とを連通させ
る第２オリフィス５４が形成されている。この第２オリ
フィス５４はアンチスキッド制御時等において緩増圧動
作を行うための、ブレーキ液の流量制限用オリフィスで
ある。また、ピストン４８の他端側の外周面には、第１
オリフィス３５や背圧抜き孔４９を覆うように第２フィ
ルタ１３が外嵌されて取りつけられている。嵌合孔３９
の内周面とハウジング主体３１の他端側の外周面との間
で形成され、第１シール部材４１と第２シール部材４３
とでシールされた領域（第２液圧室）１２内に、第２フ
ィルタ１３は配置される。On the other end side of the large-diameter cylindrical portion 48a of the piston 48 (the end portion in contact with the second valve seat member 47), the inner peripheral region of the piston 48 and the downstream hydraulic chamber 11 are provided. A second orifice 54 for communication is formed. The second orifice 54 is an orifice for restricting the flow rate of the brake fluid for performing a gentle pressure increasing operation at the time of anti-skid control or the like. The outer peripheral surface on the other end side of the piston 48 has a first
The second filter 13 is externally fitted and attached so as to cover the orifice 35 and the back pressure release hole 49. Fitting hole 39
Are formed between the inner peripheral surface of the housing main body 31 and the outer peripheral surface on the other end side of the housing main body 31, and the first seal member 41 and the second seal member 43 are formed.
The second filter 13 is disposed in the area (second hydraulic chamber) 12 sealed by the above.

【００３１】戻しバネ２２は、ピストン４８の大径筒部
４８ａの内側領域内に、ピストン４８の小径筒部４８ｂ
の内端面４８ｃと、第２弁座部材４７の第２支持片４７
ｂとの間に、弁軸３４に外嵌した状態で、かつ縮長した
状態で配置されている。戻しバネ２２は、ピストン４８
を第２弁座部材４７から離反する方向へ常時弾発付勢す
る。The return spring 22 is provided inside the large-diameter cylindrical portion 48a of the piston 48 within the small-diameter cylindrical portion 48b of the piston 48.
And the second support piece 47 of the second valve seat member 47.
b, it is arranged in a state fitted to the valve shaft 34 and in a contracted state. The return spring 22 includes a piston 48
Is constantly resiliently biased in a direction away from the second valve seat member 47.

【００３２】この構成により、ピストン４８を第２弁座
部材４７方向へ移動させる接近方向（図１中の右方向）
の力（接近力）を受ける受圧面の面積（第１受圧面積）
は、点線の矢印で示すごとく弁軸３４の連通孔３６を経
由してマスタシリンダ側の主液圧流路Ｉと連通する上流
側液圧室２１に配置された一方向性シール部材５２が受
圧部となることから、上流側液圧室２１の外径（つまり
第２領域Ｋ２の内径Ａ）と上流側液圧室２１の内径（つ
まり弁軸３４の外径Ｃ）との径差（Ａ−Ｃ）に対応する
大きさとなる。また、切換弁１０および主弁５が共に開
状態の際にマスタシリンダＭ／Ｃ側の主液圧流路Ｉから
ピストン４８が受ける、ピストン４８を第２弁座部材４
７から離反させる方向へ移動させる離反力を受ける受圧
面は、通常のブレーキ動作時には、大径筒部４８ａの他
端側端面と大径筒部４８ａの内周側に臨む小径筒部４８
ｂの内端面とになるから、この離反力を受ける第２受圧
面積は、下流側液圧室１１の外径（つまり第３領域Ｋ３
の内径Ｂ）と弁軸３４の外径Ｃとの径差（Ｂ−Ｃ）に対
応する大きさとなる。また、切換弁１０が絞り状態にあ
って主弁５が開状態の際に、マスタシリンダＭ／Ｃ側の
主液圧流路Ｉからピストン４８が受ける離反力の受圧面
は、大径筒部４８ａの内周側に臨む小径筒部４８ｂの内
端面４８ｃとなるから、この状態においてこの離反力を
受ける第３受圧面積は、ピストン４８の戻しバネ２２が
収容された部位の内径Ｄと弁軸３４の外径Ｃとの径差
（Ｄ−Ｃ）に対応する大きさとなる。そして、これら３
つの受圧面積の大小関係は、内径Ｂ＞内径Ａ＞内径Ｄと
いう関係があるから、 第２受圧面積＞第１受圧面積>第３受圧面積 となる。With this configuration, the approach direction (rightward in FIG. 1) for moving the piston 48 toward the second valve seat member 47.
Area of the pressure receiving surface (first pressure receiving area) which receives the force (approaching force)
The one-way seal member 52 disposed in the upstream hydraulic chamber 21 communicating with the main hydraulic flow path I on the master cylinder side via the communication hole 36 of the valve shaft 34 as shown by the dotted arrow Therefore, the diameter difference (A−) between the outer diameter of the upstream hydraulic chamber 21 (ie, the inner diameter A of the second region K2) and the inner diameter of the upstream hydraulic chamber 21 (ie, the outer diameter C of the valve shaft 34). The size corresponds to C). When the switching valve 10 and the main valve 5 are both in the open state, the piston 48 receives the piston 48 from the main hydraulic pressure flow path I on the master cylinder M / C side.
During normal braking operation, the pressure-receiving surface receiving the separating force for moving in the direction to separate from the small-diameter tube 7 has the other end surface of the large-diameter cylindrical portion 48a and the small-diameter cylindrical portion 48 facing the inner peripheral side of the large-diameter cylindrical portion 48a.
b, the second pressure receiving area receiving the repelling force is equal to the outer diameter of the downstream hydraulic chamber 11 (that is, the third area K3).
Of the valve shaft 34 and an outer diameter C of the valve shaft 34 (B-C). When the switching valve 10 is in the throttled state and the main valve 5 is in the open state, the pressure receiving surface of the separating force received by the piston 48 from the main hydraulic pressure flow path I on the master cylinder M / C side has a large-diameter cylindrical portion 48a. In this state, the third pressure receiving area which receives the separating force is the inner diameter D of the portion of the piston 48 in which the return spring 22 is accommodated and the valve shaft 34. Has a size corresponding to the diameter difference (D−C) from the outer diameter C. And these three
Since there is a relation of the inner diameter B> the inner diameter A> the inner diameter D, the relationship between the two pressure receiving areas is as follows: second pressure receiving area> first pressure receiving area> third pressure receiving area.

【００３３】次に、常開型電磁弁３０の動作について説
明する。通常ブレーキ時には図１において実線の矢印で
示すように、マスタシリンダＭ／Ｃから送出されたブレ
ーキ液は、主液圧流路Ｉ、第１液圧流路２、第１フィル
タ３、第１液圧室４、開状態の主弁５、開状態の切換弁
１０、下流側液圧室１１、第１オリフィス３５、第２液
圧室１２、第２フィルタ１３、第２液圧流路１４、主液
圧流路IIを通り、車輪ブレーキに供給される。この状態
において、急激なブレーキ動作が行われた場合には、ハ
ウジング主体３１に設けられた第１オリフィス３５が作
用して、下流側液圧室１１を含む上流側が高圧、第２液
圧室１２を含む下流側が低圧に瞬間的になる。なお、ハ
ウジング主体３１には背圧抜き孔４９も設けられている
が、ピストン４８の大径筒部・の外周面と貫通孔３３の
第３領域Ｋ３の内周面との間の隙間が、一種のオリフィ
スとして作用して背圧抜き孔４９からのブレーキ液の流
出を瞬間的に抑制する。Next, the operation of the normally open solenoid valve 30 will be described. During normal braking, as indicated by the solid arrow in FIG. 1, the brake fluid delivered from the master cylinder M / C is supplied to the main hydraulic pressure channel I, the first hydraulic pressure channel 2, the first filter 3, the first hydraulic pressure chamber. 4. Open main valve 5, open switching valve 10, downstream hydraulic chamber 11, first orifice 35, second hydraulic chamber 12, second filter 13, second hydraulic flow path 14, main hydraulic flow It passes through road II and is supplied to the wheel brakes. In this state, when a rapid braking operation is performed, the first orifice 35 provided in the housing main body 31 acts to increase the pressure on the upstream side including the downstream hydraulic chamber 11 and the second hydraulic chamber 12. Is instantaneously reduced to a low pressure. Although the housing main body 31 is also provided with a back pressure release hole 49, a gap between the outer peripheral surface of the large-diameter cylindrical portion of the piston 48 and the inner peripheral surface of the third region K3 of the through hole 33 is formed. It acts as a kind of orifice and momentarily suppresses the outflow of brake fluid from the back pressure release hole 49.

【００３４】そして、マスタシリンダＭ／Ｃからのブレ
ーキ液圧からのピストン４８に対する離反力は、下流側
液圧室１１を介してピストン４８の他端面と戻しバネ２
２が収容されたピストン４８の内周領域を介して小径筒
部４８ｂの内端面４８ｃとに加わり、また接近力は図１
の点線で示す矢印のように、上流側液圧室２１と一方向
性シール部材５２を介してピストン４８の一端側に加わ
るが、内径Ｂ＞内径Ａ（すなわち第２受圧面積＞第１受
圧面積）、という関係があるから、ピストン４８には、
ピストン４８を第２弁座部材４７から離反する方向への
力が作用する。従って、戻しバネ２２の付勢力が弱くて
も、ピストン４８が誤って第２弁座部材４７側へ移動
し、切換弁１０が閉状態（絞り状態）となることはな
い。The repulsive force on the piston 48 from the brake fluid pressure from the master cylinder M / C is applied to the other end face of the piston 48 via the downstream hydraulic chamber 11 and the return spring 2.
2 is applied to the inner end surface 48c of the small-diameter cylindrical portion 48b through the inner peripheral area of the piston 48 in which the piston 2 is accommodated.
As shown by the dotted line arrow, it is applied to one end of the piston 48 via the upstream hydraulic chamber 21 and the one-way sealing member 52, but the inner diameter B> the inner diameter A (that is, the second pressure receiving area> the first pressure receiving area). ), The piston 48 has
A force acts in a direction away from the piston 48 from the second valve seat member 47. Therefore, even if the urging force of the return spring 22 is weak, the piston 48 does not accidentally move to the second valve seat member 47 side, and the switching valve 10 does not enter the closed state (throttle state).

【００３５】ブレーキ制御装置がアンチスキッドまたは
トラクション制御中において、電磁石１５が通電されて
可動コア１６によって弁軸３４が駆動され、図２に示す
ように主弁５のみが閉状態となると、主液圧流路Ｉから
供給されるブレーキ液からの接近力は、ピストン４８の
一端側に加わったままであるが、ピストン４８への離反
力は、主液圧流路Ｉから供給されるブレーキ液からの液
圧に代えて、主液圧流路II側からのブレーキ液の液圧、
つまり第２液圧流路１４のブレーキ液圧に基づいて発生
する。そして、主液圧流路IIからのブレーキ液は、ピス
トン４８の凸部５３が形成された他端側の端面と小径筒
部４８ｂの内端面４８ｃとに加わるが、背圧用液圧室５
０にも逆に接近力として作用するから、実質的に主液圧
流路IIからのブレーキ液の液圧に基づいて発生する離反
力が作用する受圧面積は、内径差（Ａ−Ｃ）に対応した
面積となり、接近力の受圧面積と離反力の受圧面積とが
等しくなる。そして、アンチスキッドまたはトラクショ
ン制御開始直後では、主液圧流路Ｉ（つまり第１液圧流
路２）のブレーキ液圧の方が、主液圧流路II（つまり第
２液圧流路１４）のブレーキ液圧よりも高圧であるか
ら、ピストン４８は戻しバネ２２の付勢力に抗して主液
圧流路Ｉから供給されるブレーキ液からの接近力によっ
て、瞬時に第２弁座部材４７側へ移動し、その他端が第
２弁座部材４７と当接する。これにより、図３に示すよ
うに切換弁１０が絞り状態になる。When the electromagnet 15 is energized and the movable core 16 drives the valve shaft 34 during the anti-skid or traction control of the brake control device, and only the main valve 5 is closed as shown in FIG. The approaching force from the brake fluid supplied from the pressure passage I remains applied to one end of the piston 48, but the repulsion force to the piston 48 is caused by the hydraulic pressure from the brake fluid supplied from the main hydraulic passage I. Instead of the hydraulic pressure of the brake fluid from the main hydraulic pressure flow path II side,
That is, it is generated based on the brake fluid pressure in the second fluid pressure passage 14. Then, the brake fluid from the main hydraulic pressure channel II is applied to the end face on the other end side of the piston 48 on which the convex portion 53 is formed and the inner end face 48c of the small-diameter cylindrical portion 48b.
Since it acts as an approaching force on the contrary to 0, the pressure receiving area on which the separating force generated substantially based on the hydraulic pressure of the brake fluid from the main hydraulic pressure flow path II corresponds to the inner diameter difference (AC) The pressure receiving area of the approaching force and the pressure receiving area of the separating force are equal. Immediately after the start of the anti-skid or traction control, the brake hydraulic pressure in the main hydraulic flow path I (that is, the first hydraulic pressure flow path 2) becomes larger than the brake hydraulic pressure in the main hydraulic flow path II (that is, the second hydraulic pressure flow path 14). Since the pressure is higher than the pressure, the piston 48 instantaneously moves to the second valve seat member 47 side by the approaching force from the brake fluid supplied from the main hydraulic pressure flow path I against the urging force of the return spring 22. The other end abuts on the second valve seat member 47. Thereby, the switching valve 10 is brought into the throttled state as shown in FIG.

【００３６】この切換弁１０の開状態から絞り状態への
移行の際には、戻しバネ２２はそれを阻止する方向の力
（離反力）をピストン４８に作用させるが、前述した理
由により従来の常開型電磁弁に比べて戻しバネ２２の弾
性力を弱く設定できるから、切換弁１０の開状態から絞
り状態への移行が、従来例よりも迅速に行われる。つま
り、切換弁１０の応答性が向上する。なお、本実施の形
態の弁軸３４は略同じ直径に形成されているため、その
両端に作用するブレーキ液からの液圧が相殺される形と
なり、ブレーキ液の液圧は、弁軸３４の駆動には影響は
与えない。よって、弁孔６を大きくして弁軸３４の直径
を大きくしても、電磁石１５を大型化することなく、弁
軸３４のスムーズな駆動が行える。そして、弁孔６を大
きくすると、通常のブレーキ動作時の応答性が向上でき
るという効果がある。When the switching valve 10 shifts from the open state to the throttled state, the return spring 22 applies a force (separation force) to the piston 48 in a direction in which it is prevented. Since the elastic force of the return spring 22 can be set to be weaker than that of the normally-open solenoid valve, the switching from the open state of the switching valve 10 to the throttle state is performed more quickly than in the conventional example. That is, the responsiveness of the switching valve 10 is improved. Since the valve shaft 34 of the present embodiment is formed to have substantially the same diameter, the hydraulic pressure from the brake fluid acting on both ends of the valve shaft 34 is offset, and the hydraulic pressure of the brake fluid is The drive is not affected. Therefore, even if the diameter of the valve shaft 34 is increased by enlarging the valve hole 6, the valve shaft 34 can be smoothly driven without increasing the size of the electromagnet 15. When the valve hole 6 is enlarged, there is an effect that responsiveness during a normal braking operation can be improved.

【００３７】その後、電磁石１５が予め設定されたオン
・オフ時間で作動して弁軸３４を駆動し、切換弁１０が
絞り状態を維持したまま主弁５が開状態、閉状態を繰り
返すことによって、主弁５と切換弁１０とが共に閉状態
となって一旦大きく下がった車輪ブレーキ側の主液圧流
路IIの液圧を、段階的にマスタシリンダ側の主液圧流路
Ｉの液圧に近づけて行くという、アンチスキッドまたは
トラクション制御動作の中のいわゆる「緩増圧」動作状
態に入る。そして図３に示す主弁５と切換弁１０とが共
に閉状態にある状態から、電磁石１５がオフとなって、
弁軸用バネ４６の付勢力で弁軸３４が弁座部材４４から
離れ、主弁５が開状態になる図４の状態に移行すると、
主液圧流路Ｉのブレーキ液は、ピストン４８の大径筒部
４８ａに設けられた第２オリフィス５４を介して、流量
が制限されて下流側液圧室１１に供給され、供給された
ブレーキ液は第２液圧室１２→第２液圧流路１４→主液
圧流路IIという経路で車輪ブレーキに供給される。これ
により、主液圧流路IIの液圧は緩やかに増圧される。Thereafter, the electromagnet 15 operates at a preset ON / OFF time to drive the valve shaft 34, and the main valve 5 repeats the open state and the closed state while the switching valve 10 maintains the throttled state. When the main valve 5 and the switching valve 10 are both closed, the hydraulic pressure in the main hydraulic passage II on the wheel brake side, which has been greatly reduced, is gradually changed to the hydraulic pressure in the main hydraulic passage I on the master cylinder side. A so-called “slow pressure increase” operating state in the anti-skid or traction control operation of approaching is entered. Then, from the state where both the main valve 5 and the switching valve 10 shown in FIG. 3 are in the closed state, the electromagnet 15 is turned off,
When the urging force of the valve shaft spring 46 moves the valve shaft 34 away from the valve seat member 44 and shifts to the state shown in FIG.
The brake fluid in the main hydraulic pressure channel I is supplied to the downstream hydraulic chamber 11 at a limited flow rate through the second orifice 54 provided in the large-diameter cylindrical portion 48a of the piston 48, and the supplied brake fluid Is supplied to the wheel brakes along a path of the second hydraulic chamber 12 → the second hydraulic path 14 → the main hydraulic path II. Thereby, the hydraulic pressure of the main hydraulic pressure channel II is gradually increased.

【００３８】そして、この緩増圧動作状態においては、
主弁５が開状態となる関係上、閉状態（絞り状態）のピ
ストン４８には、小径筒部４８ｂの内端面４８ｃ（径差
（Ｄ−Ｃ）に対応した受圧面積：第３受圧面積）に主液
圧流路Ｉのブレーキ液からの液圧が離反力として加わる
と共に、大径筒部４８ａ（径差（Ａ−Ｄ）に対応した受
圧面積）に下流側液圧室１１および背圧用液圧室５０を
介して主液圧流路IIのブレーキ液の液圧が離反力として
加わる。なお、一方、一方向性シール部材５２（径差
（Ａ−Ｃ）に対応した受圧面積：第１受圧面積）には主
液圧流路Ｉのブレーキ液から上述した接近力となる液圧
が加わる。そして、上述したように、内径Ａ＞内径Ｄ
（すなわち第１受圧面積＞第３受圧面積）となり、しか
も主液圧流路Ｉ側の液圧が主液圧流路II側よりも高圧で
あるから、第１受圧面積と第３受圧面積の差分で生ずる
主液圧流路Ｉのブレーキ液からの液圧による接近力は、
戻しバネ２２からの離反力に主液圧流路IIからの離反力
を加えた離反力の合計よりも大きく、ピストン４８には
全体として常に第２弁座部材４７側へ向かう力が作用す
ることになり、第１受圧面積と第３受圧面積の差分で生
ずる液圧が戻しバネ２２等からの離反力を下回るまで、
切換弁１０は絞り状態を維持する。In this slow pressure increasing operation state,
Due to the main valve 5 being in the open state, the piston 48 in the closed state (restricted state) has an inner end surface 48c of the small-diameter cylindrical portion 48b (a pressure receiving area corresponding to the diameter difference (DC): a third pressure receiving area). The hydraulic pressure from the brake fluid in the main hydraulic flow path I is applied as a repulsive force, and the large-diameter cylindrical portion 48a (pressure receiving area corresponding to the diameter difference (A-D)) is connected to the downstream hydraulic chamber 11 and the back pressure fluid. The hydraulic pressure of the brake fluid in the main hydraulic pressure channel II is applied via the pressure chamber 50 as a separating force. On the other hand, the one-way seal member 52 (the pressure receiving area corresponding to the diameter difference (AC): the first pressure receiving area) receives the above-described hydraulic pressure from the brake fluid in the main hydraulic pressure channel I as the approaching force. . And, as described above, the inner diameter A> the inner diameter D
(That is, first pressure receiving area> third pressure receiving area), and since the hydraulic pressure on the main hydraulic pressure flow path I side is higher than that on the main hydraulic pressure flow path II side, the difference between the first pressure receiving area and the third pressure receiving area is obtained. The resulting approaching force of the main hydraulic flow path I due to the hydraulic pressure from the brake fluid is:
The total force is greater than the sum of the repulsion force from the return spring 22 and the repulsion force from the main hydraulic pressure flow path II, and the piston 48 always receives a force toward the second valve seat member 47 as a whole. Until the hydraulic pressure generated by the difference between the first pressure receiving area and the third pressure receiving area falls below the repulsive force from the return spring 22 or the like.
The switching valve 10 maintains the throttle state.

【００３９】その後、アンチスキッドまたはトラクショ
ン制御動作期間中は、電磁石１５が繰り返しオン・オフ
され、図３の状態と図４の状態とを繰り返す。そして、
図４の状態になる度に、主液圧流路II側の液圧が段階的
に増圧されて主液圧流路Ｉの液圧に近づく。そして、ピ
ストン４８が主液圧流路Ｉのブレーキ液から受ける液圧
よりも、ピストン４８が主液圧流路IIのブレーキ液から
受ける液圧と戻しバネ２２の付勢力との合計圧力の方が
大きくなると、主弁５が開状態になった際にピストン４
８が第２弁座部材４７からの離反を開始する。ここで、
本実施の形態では、前述のように戻しバネ２２の弾性力
を弱く設定できるから、従来に比べて主液圧流路Ｉのブ
レーキ液の液圧に主液圧流路IIのブレーキ液の液圧がよ
り近づいて初めて、つまり復帰差圧がより小さい状態で
ピストン４８が離反を開始するようになる。そして、ピ
ストン４８が一旦離反し始めると、ピストン４８の大径
筒部４８ａの内周側だけでなく下流側液圧室１１に面す
る他端面にも主液圧流路Ｉからの液圧が離反する方向に
加わるから、この液圧による離反力の内の内径Ａ分は、
上流側液圧室２１から加わる接近力をキャンセルし、残
りの内径差（Ｂ−Ａ）に対応した面積に主液圧流路Ｉと
主液圧流路IIとの液圧差を掛けた値の圧力が、離反力と
して戻しバネ２２の付勢力に加算されてピストン４８に
作用し、切換弁１０は迅速に開状態に移行して図１に示
す状態になる。これでアンチスキッドまたはトラクショ
ン制御動作が終了し、通常のブレーキ動作になる。この
場合でもやはり、戻しバネ２２からの付勢力が小さくて
も、主液圧流路Ｉの液圧＞主液圧流路IIの液圧、という
関係があるから、主液圧流路Ｉの液圧と主液圧流路IIの
液圧との液圧差によってピストン４８は確実に第２弁座
部材４７から離反できる。このように、戻しバネ２２の
弾性力、つまりピストン４８への戻しバネ２２の付勢力
を従来に比べて非常に弱くすることが可能で、復帰差圧
を小さくすることができるから、切換弁の動作反応が緩
やかになり、切換弁を絞り状態に維持でき、アンチロッ
ク制御の制御性が向上する。特に、路面の摩擦係数が低
い場合に、車輪ブレーキ側の液圧変化が非常に小さいの
で、復帰差圧を小さくすることによって、制御性が良好
になる。しかも内径差（Ｂ−Ａ）を、さらに小さくする
ように設定することも可能であるから、より一層復帰差
圧を小さくすることも可能である。Thereafter, during the anti-skid or traction control operation, the electromagnet 15 is repeatedly turned on and off, and the state of FIG. 3 and the state of FIG. 4 are repeated. And
Each time the state shown in FIG. 4 is reached, the hydraulic pressure on the main hydraulic pressure flow path II side is increased stepwise and approaches the hydraulic pressure of the main hydraulic pressure flow path I. The total pressure of the hydraulic pressure received by the piston 48 from the brake fluid in the main hydraulic pressure channel II and the urging force of the return spring 22 is larger than the hydraulic pressure received by the piston 48 from the brake fluid in the main hydraulic pressure channel I. When the main valve 5 is opened, the piston 4
8 starts separating from the second valve seat member 47. here,
In the present embodiment, since the elastic force of the return spring 22 can be set to be weak as described above, the hydraulic pressure of the brake fluid in the main hydraulic pressure passage II is lower than that of the conventional hydraulic fluid. Only when approaching, that is, when the return differential pressure is smaller, the piston 48 starts to separate. Then, once the piston 48 begins to separate, the hydraulic pressure from the main hydraulic flow path I separates not only on the inner peripheral side of the large-diameter cylindrical portion 48a of the piston 48 but also on the other end face facing the downstream hydraulic chamber 11. The inner diameter A of the repulsion force due to the hydraulic pressure is:
The approach force applied from the upstream hydraulic pressure chamber 21 is canceled, and the pressure corresponding to the value obtained by multiplying the area corresponding to the remaining inner diameter difference (BA) by the hydraulic pressure difference between the main hydraulic pressure flow path I and the main hydraulic pressure flow path II is obtained. Is added to the biasing force of the return spring 22 as a separating force, and acts on the piston 48, so that the switching valve 10 quickly shifts to the open state to reach the state shown in FIG. Thus, the anti-skid or traction control operation is completed, and a normal braking operation is performed. Even in this case, even if the urging force from the return spring 22 is small, there is a relationship that the hydraulic pressure of the main hydraulic pressure channel I> the hydraulic pressure of the main hydraulic pressure channel II. The piston 48 can be surely separated from the second valve seat member 47 by the hydraulic pressure difference from the hydraulic pressure of the main hydraulic pressure channel II. As described above, the elastic force of the return spring 22, that is, the urging force of the return spring 22 to the piston 48 can be made extremely weaker than before, and the return differential pressure can be reduced. The operation response becomes gentle, the switching valve can be maintained in the throttle state, and the controllability of the antilock control is improved. In particular, when the coefficient of friction on the road surface is low, the change in hydraulic pressure on the wheel brake side is very small. Therefore, the controllability is improved by reducing the return differential pressure. In addition, since the inner diameter difference (BA) can be set to be smaller, the return differential pressure can be further reduced.

【００４０】なお、ブレーキリリース時には、ブレーキ
液は、ピストン４２の作動の有無にかかわらず、背圧抜
き孔４９→一方向性シール部材５２→上流側液圧室２１
→ガイド筒３７内部→弁軸３４の連通孔３６→第１液圧
室４→第１液圧流路２という経路で流出する。When the brake is released, the brake fluid is supplied to the back pressure release hole 49, the one-way sealing member 52, and the upstream hydraulic chamber 21 regardless of the operation of the piston 42.
The fluid flows out along the path of → inside the guide cylinder 37 → communication hole 36 of the valve shaft 34 → first hydraulic pressure chamber 4 → first hydraulic pressure flow path 2.

【００４１】[0041]

【発明の効果】本発明に係る常開型電磁弁によれば、主
弁と切換弁とが共に開状態にある通常ブレーキ動作時に
は、マスタシリンダ側の主液圧流路からの液圧が第１受
圧面と第２受圧面に加わるが、貫通孔の第３領域内に形
成された第２受圧面の方が、第２領域内に形成された第
１受圧面よりも確実に面積が広いため、ピストンには常
に開状態を維持する方向の力が作用する。よって、マス
タシリンダの急踏み込み時にもピストンが誤動作して絞
り状態に移行することはない。従って、ピストンを絞り
状態から開状態に戻すための戻しバネが一般的に常開型
電磁弁には使用されているが、この戻しバネの付勢力を
従来に比べて非常に小さくすることが可能となり、復帰
差圧を小さくすることができるから、切換弁の動作反応
が緩やかになり、切換弁を絞り状態に維持でき、アンチ
ロック制御の制御性が向上する。According to the normally open solenoid valve of the present invention, during normal braking operation in which both the main valve and the switching valve are open, the hydraulic pressure from the main hydraulic pressure passage on the master cylinder side is reduced to the first pressure. It is applied to the pressure receiving surface and the second pressure receiving surface, but the area of the second pressure receiving surface formed in the third region of the through hole is surely larger than that of the first pressure receiving surface formed in the second region. , A force is applied to the piston in such a direction as to keep the piston open. Therefore, even when the master cylinder is suddenly depressed, the piston does not malfunction and does not shift to the throttle state. Therefore, a return spring for returning the piston from the throttled state to the open state is generally used in a normally-open solenoid valve, but the biasing force of this return spring can be made much smaller than in the past. Since the return differential pressure can be reduced, the operation response of the switching valve becomes gentle, the switching valve can be maintained in the throttle state, and the controllability of the antilock control is improved.

【００４２】また、請求項２や請求項３の構成によれ
ば、アンチロック動作やトラクション動作から通常ブレ
ーキ動作へ移行する復帰差圧が略一定となり、制動フィ
ーリングが良好になる。また、請求項４の構成によれ
ば、ピストンと共に移動する際に、貫通孔の第２領域の
内周面と弁軸の外周面とからシール部材が受ける摩擦力
が、従来のＯリングの場合に比べて小さくなり、切換弁
の応答性が向上する、という効果がある。According to the second and third aspects of the present invention, the return differential pressure for shifting from the antilock operation or the traction operation to the normal braking operation becomes substantially constant, and the braking feeling is improved. Further, according to the configuration of claim 4, when the seal member receives the frictional force from the inner peripheral surface of the second region of the through hole and the outer peripheral surface of the valve shaft when moving with the piston, the conventional O-ring is used. And the response of the switching valve is improved.

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

【図１】本発明に係る常開型電磁弁の構成を説明するた
めの断面図である（通常ブレーキ動作時）。FIG. 1 is a cross-sectional view for explaining a configuration of a normally-open solenoid valve according to the present invention (during normal brake operation).

【図２】主弁が閉状態で、切換弁が開状態となっている
状態を示す断面図である。FIG. 2 is a sectional view showing a state in which a main valve is in a closed state and a switching valve is in an open state.

【図３】主弁が閉状態で、切換弁が閉状態（絞り状態）
となっている状態を示す断面図である。FIG. 3 shows a main valve in a closed state and a switching valve in a closed state (throttle state).
FIG. 4 is a cross-sectional view showing the state of FIG.

【図４】主弁は開状態であるが、切換弁が閉状態にある
状態を示す断面図である。FIG. 4 is a cross-sectional view showing a state in which a main valve is in an open state and a switching valve is in a closed state.

【図５】常開型電磁弁が使用される車両用アンチロック
ブレーキ装置の一般的な液圧回路図である。FIG. 5 is a general hydraulic circuit diagram of a vehicular anti-lock brake device using a normally open solenoid valve.

【図６】従来の常開型電磁弁の構造を説明するための断
面図である。FIG. 6 is a cross-sectional view for explaining the structure of a conventional normally-open solenoid valve.

【符号の説明】[Explanation of symbols]

Ｉ 主液圧流路（マスタシリンダ側） II 主液圧流路（車輪ブレーキ側） ５ 主弁 ６ 弁孔 １０ 切換弁 １５ 電磁石 １８ 固定コア ３１ ハウジング主体 ３３ 貫通孔 ３４ 弁軸 ３４ａ 弁体 ３６ 連通孔 ４４ 弁座部材 ４７ 第２弁座部材 ４７ａ 第２弁孔 ４８ ピストン Ｋ１ 貫通孔の第１領域 Ｋ２ 貫通孔の第２領域 Ｋ３ 貫通孔の第３領域 I Main hydraulic pressure flow path (master cylinder side) II Main hydraulic pressure flow path (wheel brake side) 5 Main valve 6 Valve hole 10 Switching valve 15 Electromagnet 18 Fixed core 31 Housing main body 33 Through hole 34 Valve shaft 34a Valve body 36 Communication hole 44 Valve seat member 47 Second valve seat member 47a Second valve hole 48 Piston K1 First region of through hole K2 Second region of through hole K3 Third region of through hole

───────────────────────────────────────────────────── フロントページの続き (72)発明者 増田 直己 長野県上田市大字国分840番地 日信工業 株式会社内 Ｆターム(参考） 3D046 BB03 BB28 CC02 LL23 LL33 LL50 LL55 3D049 BB08 BB18 HH20 HH30 HH36 HH53 JJ05 JJ06 JJ08 3H106 DA03 DA12 DA23 DA33 DB02 DB12 DB23 DB32 DC02 DD09 EE27 GC11 KK22  ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Naoki Masuda 840 Kokubu, Ueda-shi, Nagano F-term (reference) 3D046 BB03 BB28 CC02 LL23 LL33 LL50 LL55 3D049 BB08 BB18 HH20 HH30 HH36 HH53 JJ05 JJ06 JJ08 3H106 DA03 DA12 DA23 DA33 DB02 DB12 DB23 DB32 DC02 DD09 EE27 GC11 KK22

Claims (4)

【特許請求の範囲】[Claims] 【請求項１】 マスタシリンダと車輪ブレーキとの間の
主液圧流路に介装され、弁座部材に形成された弁孔に電
磁駆動される弁軸に設けられた弁体が接離動することに
よって前記主液圧流路を非連通または連通の状態にする
主弁と、該主弁と直列に主液圧流路に介装され、マスタ
シリンダ側と車輪ブレーキ側の主液圧流路の液圧差によ
り、開状態と絞り状態の間で切換わる切換弁とを有する
常開型電磁弁において、 一端側が電磁石の固定コアに形成され、内部には該一端
側から他端側に貫通すると共に一端側から他端側に向け
て順番に、前記弁軸が摺動自在に装着される第１領域、
該第１領域の内径よりも内径が大径な第２領域および該
第２領域の内径よりも内径が大径な第３領域に区分けさ
れる貫通孔が形成されたハウジング主体を具備し、 前記弁軸は、内部に軸線に沿って連通孔が形成されると
共に、前記第３領域に突出する先端が前記弁体に形成さ
れ、 前記弁座部材は、前記ハウジング主体の他端側に取り付
けられ、中心には前記貫通孔を前記マスタシリンダ側の
主液圧流路に連通させる前記弁孔が形成され、 前記切換弁は、 前記貫通孔の前記第３領域内に配置され、中心に前記弁
軸が挿通する第２弁孔が形成された第２弁座部材と、 外形が筒状に形成されると共に、前記貫通孔の前記第３
領域内に、外周面が第３領域の内面に接触し、かつ前記
弁軸が挿通された状態で前記ハウジング主体の長手方向
に沿って摺動自在に配置され、一端側の外径および内径
が他端側よりも小径に形成されて該一端側が貫通孔の前
記第２領域内に進入し、前記他端側が前記第２弁座部材
と接離するピストンとを有し、 前記弁軸の前記連通孔を経由して前記マスタシリンダ側
の主液圧流路に連通する前記第２領域内に位置してマス
タシリンダ側の主液圧流路から前記ピストンを前記第２
弁座部材方向へ移動させる接近力を受けるピストンの前
記一端側の受圧面積は、切換弁および前記主弁が共に開
状態の際にマスタシリンダ側の主液圧流路からピストン
を第２弁座部材から離反させる方向へ移動させる離反力
を受けるピストンの受圧面積よりも小さく、かつ切換弁
が絞り状態にあって主弁が開状態の際にマスタシリンダ
側の主液圧流路からピストンが受ける前記離反力の受圧
面積よりも大きいことを特徴とする常開型電磁弁。1. A valve element provided on a valve shaft which is interposed in a main hydraulic pressure passage between a master cylinder and a wheel brake and which is electromagnetically driven in a valve hole formed in a valve seat member, moves in and out. A main valve for disconnecting or communicating the main hydraulic flow passage, and a hydraulic pressure difference between the main hydraulic flow passage on the master cylinder side and the main hydraulic flow passage on the wheel brake side, which is interposed in the main hydraulic flow passage in series with the main valve. A normally open solenoid valve having a switching valve that switches between an open state and a throttle state, wherein one end side is formed in a fixed core of the electromagnet, and internally penetrates from one end side to the other end side; A first region in which the valve shaft is slidably mounted in order from
A housing main body having a through-hole divided into a second region having an inner diameter larger than the inner diameter of the first region and a third region having an inner diameter larger than the inner diameter of the second region; The valve shaft has a communication hole formed therein along the axis, and a tip protruding into the third region is formed in the valve body, and the valve seat member is attached to the other end of the housing main body. The valve hole is formed at the center for communicating the through hole with the main hydraulic pressure flow path on the master cylinder side. The switching valve is disposed in the third region of the through hole, and the valve shaft is formed at the center. A second valve seat member formed with a second valve hole through which the second valve hole is inserted;
In the region, the outer peripheral surface is in contact with the inner surface of the third region, and is slidably disposed along the longitudinal direction of the housing main body in a state where the valve shaft is inserted. A piston formed to have a smaller diameter than the other end side, the one end side entering the second region of the through hole, and the other end side being in contact with and separating from the second valve seat member; The piston is moved from the main hydraulic passage on the master cylinder side to the second position in the second region communicating with the main hydraulic passage on the master cylinder side through a communication hole.
The pressure receiving area on the one end side of the piston which receives the approaching force for moving in the direction of the valve seat member is such that when the switching valve and the main valve are both open, the piston is moved from the main hydraulic pressure flow path on the master cylinder side to the second valve seat member. When the switching valve is in the throttled state and the main valve is open, the separation received by the piston from the main hydraulic pressure flow path on the master cylinder side is smaller than the pressure receiving area of the piston that receives the separating force that moves in the direction to separate from the main cylinder. A normally open solenoid valve characterized by being larger than the pressure receiving area. 【請求項２】 前記ピストンの前記第２弁座部材と当接
する他端側の端面には、環状の凸部が形成されているこ
とを特徴とする請求項１記載の常開型電磁弁。2. The normally-open solenoid valve according to claim 1, wherein an annular convex portion is formed on the other end surface of the piston abutting on the second valve seat member. 【請求項３】 前記凸部は、前記ピストンの他端側の端
面の内周縁若しくは外周縁に形成されていることを特徴
とする請求項２記載の常開型電磁弁。3. The normally-open solenoid valve according to claim 2, wherein the projection is formed on an inner peripheral edge or an outer peripheral edge of an end face on the other end side of the piston. 【請求項４】 前記ハウジング主体の前記第２領域に
は、前記弁軸の外周面と第２領域の内周面との間をシー
ルして前記マスタシリンダ側の主液圧流路からの液圧を
前記ピストンに伝える断面Ｖ字状の一方向性シール部材
が、弁軸に外嵌された状態で配置されていることを特徴
とする請求項１，２または３記載の常開型電磁弁。4. The second region mainly of the housing seals a gap between an outer peripheral surface of the valve shaft and an inner peripheral surface of the second region to provide a hydraulic pressure from a main hydraulic passage on the master cylinder side. The normally-open solenoid valve according to claim 1, 2 or 3, wherein a one-way sealing member having a V-shaped cross section for transmitting the pressure to the piston is arranged so as to be fitted on the valve shaft.