JP2005036960A - Automatic speed changing valve for 2-speed hydraulic motor - Google Patents

Automatic speed changing valve for 2-speed hydraulic motor Download PDF

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JP2005036960A
JP2005036960A JP2003409725A JP2003409725A JP2005036960A JP 2005036960 A JP2005036960 A JP 2005036960A JP 2003409725 A JP2003409725 A JP 2003409725A JP 2003409725 A JP2003409725 A JP 2003409725A JP 2005036960 A JP2005036960 A JP 2005036960A
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spool
speed
pressure
small diameter
small
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JP3863141B2 (en
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Makoto Ejiri
誠 江尻
Takaya Yokota
貴也 横田
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Nachi Fujikoshi Corp
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Nachi Fujikoshi Corp
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Abstract

<P>PROBLEM TO BE SOLVED: To provide an automatic speed changing valve for a 2-speed hydraulic motor capable of reducing a hysteresis without enlarging the diameter of a 2-speed spool 10, or reducing the diameter of each small diameter spool in changing the 2-speed hydraulic motor between a high-speed state and a low-speed state. <P>SOLUTION: In this automatic speed changing valve 7, external pilot pressure P<SB>P</SB>is introduced to an outward end part of the first small-diameter spool C and the 2-speed spool. High pressure port pressure P<SB>A, B</SB>is constantly introduced from a center port A, B of the changing valve 7 through a radial hole 18 into a hollow hole 20. When the changing valve 7 is at a low-speed side position, the high pressure port pressure is applied to the second small diameter spool B and the third small diameter spool D only. When the changing valve 7 is at a high speed side position, the high pressure port pressure is applied to each inward end surface of the first small diameter spool C and the second small diameter spool B. The diameter D3 of the spool C is set to be smaller than the diameter D2 of the spool B, and larger than the diameter D4 of the spool D. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

本発明は、建設機械用のクローラーを駆動するための２速油圧モータにおいて、モータに作用する負荷の大きさにより低速と高速の切換を自動的に行う２速油圧モータの自動変速切換弁に関する。   The present invention relates to an automatic transmission switching valve for a two-speed hydraulic motor that automatically switches between a low speed and a high speed in accordance with the magnitude of a load acting on the motor in a two-speed hydraulic motor for driving a crawler for a construction machine.

従来技術の２速油圧モータの自動変速切換弁は、例えば特許文献１の図３、図４に記載するものがある。特許文献１の図４の場合、２速モータの低速と高速を切換える切換弁は、外部からのパイロット圧力を受けて高速側位置へ切換わった状態になっている。油圧モータに作用する負荷が大きくなり、油圧モータの高圧ポートの圧力がシャトル弁を通って切換弁に入って来る。この圧力が、外部からのパイロット圧と対抗しており、所定の圧力以上に大きくなった時に、切換弁は低速側位置に切換わる。又、油圧モータの負荷が小さくなり、シャトル弁を通して切換弁に入って来る圧力が所定の圧力以下になった時に、切換弁は高速側位置に切換わる。切換弁の２つの切換設定圧力をＰHi→LO（高速→低速）、ＰLO→Hi（低速→高速）とすると、ＰHi→LOとＰLO→Hiの２つの切換設定圧力はスプール（本発明では２速スプールとして示す）内の隔壁で閉じられたスプールの２個の小径穴に収容された２個の丸棒部材（受圧面積調整部材−本発明では小径スプールとして示す）により調整して、ヒステリシスを設けている。これにより、油圧モータの自動変速の圧力変動に起因するハンチングを防止するものである。
特開２００３−２８１０２号公報 図３、図４ Examples of conventional automatic transmission switching valves for two-speed hydraulic motors are shown in FIGS. 3 and 4 of Patent Document 1, for example. In the case of FIG. 4 of Patent Document 1, the switching valve for switching between the low speed and the high speed of the two-speed motor is in a state of being switched to the high speed side position in response to the pilot pressure from the outside. The load acting on the hydraulic motor increases, and the pressure of the high pressure port of the hydraulic motor enters the switching valve through the shuttle valve. When this pressure is opposed to the pilot pressure from the outside and becomes larger than a predetermined pressure, the switching valve is switched to the low speed side position. Further, when the load of the hydraulic motor becomes small and the pressure entering the switching valve through the shuttle valve becomes a predetermined pressure or lower, the switching valve is switched to the high speed side position. If the two switching setting pressures of the switching valve are P Hi → LO (high speed → low speed) and P LO → Hi (low speed → high speed), the two switching setting pressures P Hi → LO and P LO → Hi are In the present invention, it is adjusted by two round bar members (pressure-receiving area adjusting member-shown as a small-diameter spool in the present invention) accommodated in two small-diameter holes of the spool closed by the inner partition wall. Hysteresis is provided. This prevents hunting due to pressure fluctuations in automatic shifting of the hydraulic motor.
JP, 2003-28102, A FIG. 3, FIG.

しかしながら、特許文献１の従来技術では、切換弁の切換設定圧力ＰHi→LO（高速→低速）とＰLO→Hi（低速→高速）に大きなヒステリシスがあり、ＰLO→Hiの設定圧力が低く設定されている。切換弁を高速側位置で油圧モータを急駆動させた場合に、油圧モータの圧力が急上昇するために、一担低速側位置に切換わり、次に油圧モータの負荷圧力が下がり高速側位置に戻るが、ＰLO→Hiの切換設定圧力が低いために応答性が悪く、切換弁が低速側から高速側に戻るまでのタイムラグが大きく、スムーズな発進ができない。このため、ＰHi→LOの切換設定圧力はそのままで、ＰLO→Hiの切換設定圧力のみを高くする必要がある。その場合には、主スプールの外径を大きくするか、又はスプリング側の丸棒部材の外径を小さくする必要がある。主スプールの外径Ｄ1 を大きくする場合は、弁体が大きくなり、スプリング側の丸棒部材の外径Ｄ2 を小さくする場合は、加工が難しくなる。又、スプリング側の丸棒部材の外径Ｄ2 を小さくすると、ＰLO→Hiの切換設定圧力が大きくなり、それと同時にＰHi→LOの切換設定圧力が大きくなる。そのため、ＰHi→LOを変更せずに、ＰLO→Hiを大きくして、ヒステリシスを小さくする場合、外部パイロット側の丸棒部材の外径Ｄ3 も小さくしなくてはならず、加工が難しくなる。スプール径を大きくする場は弁体が大きくなり、各丸棒部材を小さくする場合は加工が難しくなるなどの課題があった。さらに、限られたスペースの中にスプリングを付勢しなくてはならず、スプリング力が弱いものになってしまい、主スプールを高速側に切換えるための最小外部パイロット圧力である最小切換圧力が小さいものになってしまい、作動油温度が低い時など実機の油圧システムの背圧の影響により、主スプールが勝手に高速側位置に切換ってしまう恐れがあった。 However, in the prior art of Patent Document 1, there is a large hysteresis between the switching set pressures P Hi → LO (high speed → low speed) and P LO → Hi (low speed → high speed) of the switching valve, and the set pressure of P LO → Hi is low. Is set. When the hydraulic motor is suddenly driven with the switching valve at the high speed side position, the pressure of the hydraulic motor suddenly rises, so it switches to the single low speed side position, and then the load pressure of the hydraulic motor decreases and returns to the high speed side position. However, since the switching set pressure of P LO → Hi is low, the responsiveness is poor, the time lag until the switching valve returns from the low speed side to the high speed side is large, and smooth start is not possible. For this reason, it is necessary to increase only the switching setting pressure of P LO → Hi while maintaining the switching setting pressure of P Hi → LO . In that case, it is necessary to increase the outer diameter of the main spool or to decrease the outer diameter of the spring-side round bar member. If increasing the outer diameter D 1 of the main spool valve body is increased, when reducing the outer diameter D 2 of the spring-side of the rod member, processing becomes difficult. Also, reducing the outer diameter D 2 of the spring-side of the round bar member, switch setting pressure P LO → Hi increases therewith switch setting pressure P Hi → LO is increased at the same time. Therefore, when P LO → Hi is increased to reduce hysteresis without changing P Hi → LO , the outer diameter D 3 of the round rod member on the external pilot side must also be reduced. It becomes difficult. When the spool diameter is increased, the valve body is increased, and when each round bar member is decreased, there is a problem that processing becomes difficult. Furthermore, the spring must be urged in a limited space, the spring force becomes weak, and the minimum switching pressure, which is the minimum external pilot pressure for switching the main spool to the high speed side, is small. As a result, the main spool may be arbitrarily switched to the high speed side position under the influence of the back pressure of the actual hydraulic system such as when the hydraulic oil temperature is low.

本発明の課題はかかる従来技術の課題を解決した、油圧モータの２つの切換圧力（高速→低速、低速→高速）の設定において、ヒステリシスを小さくでき、かつ主スプールである２速スプールの外径、及びスプリング力が同じでも最小切換圧力が大きく、２速スプールの外径、及びスプリング力を変更しなくても又、各丸棒部材（小径スプール）の径を小さくすることなく最小切換圧力を変更することができ、２速スプールがかってに高速側位置に切り換わってしまう恐れがより少ない、２速油圧モータの自動変速切換弁を提供することにある。   The object of the present invention is to solve the problems of the prior art. In the setting of two switching pressures (high speed → low speed, low speed → high speed) of the hydraulic motor, the hysteresis can be reduced and the outer diameter of the main spool is the second speed spool. Even if the spring force is the same, the minimum switching pressure is large. Even if the outer diameter of the 2-speed spool and the spring force are not changed, the minimum switching pressure can be reduced without reducing the diameter of each round bar member (small diameter spool). It is an object of the present invention to provide an automatic transmission switching valve for a two-speed hydraulic motor that can be changed and is less likely to cause the second-speed spool to switch to the high-speed side position.

このため本発明によると、２速油圧モータの低速状態と高速状態を切換える自動変速切換弁において、前記切換弁はハウジング内に両端が閉じられた大径スプール穴に軸方向に移動可能に嵌合された中空の２速スプールと、２速スプール両端と中間に設けられた第１、第２及び第３の小径スプール穴に軸方向に移動可能に嵌合された第１小径スプールＣ、第２小径スプールＢ及び第３小径スプールＤと、前記２速スプールの中空穴肩部と前記第２小径スプールＢとの間を離隔する方向に付勢するスプリングと、を有し、前記第１小径スプールＣ及びそれと隣接する２速スプールの外方端部には外部パイロット圧力が導かれ、外部パイロット圧力と対抗する油圧モータの高圧ポート圧力を前記切換弁のほぼ中央に設けた中央ポートから前記中空２速スプールの中央に位置する第１半径方向穴より中空穴内に常に導くようにし、前記高圧ポート圧力が第１切替設定圧力より高く前記切換弁が低速側位置にあるときは前記高圧ポート圧力を前記第２小径スプールＢ及び第３小径スプールＤに作用するようにし、前記高圧ポート圧力が第２切替設定圧力より低く前記切換弁が高速側位置にあるときは前記高圧ポート圧力は、前記第１小径スプールＣの内方端面及び前記第２小径スプールＢの内方端面に作用するようにし、前記第１小径スプールＣの径D3を第２小径スプールＢの径D2より小に、かつ前記第３小径スプールＤの径D4より大にしたことを特徴とする２速油圧モータの自動変速切換弁によって上述した本発明の課題を解決した。   Therefore, according to the present invention, in the automatic transmission switching valve for switching between the low speed state and the high speed state of the two-speed hydraulic motor, the switching valve is fitted in a large diameter spool hole whose both ends are closed in the housing so as to be movable in the axial direction. A hollow two-speed spool, a first small-diameter spool C and a second small-diameter spool C, which are fitted in first, second and third small-diameter spool holes provided in the middle between both ends of the second-speed spool so as to be movable in the axial direction. A small-diameter spool B and a third small-diameter spool D; and a spring that urges the second-speed spool in a direction to separate the shoulder of the hollow hole of the second-speed spool and the second small-diameter spool B. External pilot pressure is guided to the outer end of C and the adjacent two-speed spool, and the high pressure port pressure of the hydraulic motor, which opposes the external pilot pressure, is hollowed out from the central port provided substantially at the center of the switching valve. When the high pressure port pressure is higher than the first switching set pressure and the switching valve is in the low speed side position, the high pressure port pressure is set to the low speed side position. Acting on the second small diameter spool B and the third small diameter spool D, and when the high pressure port pressure is lower than the second switching set pressure and the switching valve is in the high speed side position, the high pressure port pressure is the first small diameter Acting on the inner end face of the spool C and the inner end face of the second small diameter spool B, the diameter D3 of the first small diameter spool C is made smaller than the diameter D2 of the second small diameter spool B and the third small diameter The above-described problem of the present invention has been solved by an automatic transmission switching valve of a two-speed hydraulic motor characterized in that the diameter is larger than the diameter D4 of the spool D.

本発明の構成により、本発明では、外部パイロット圧力と対抗する油圧モータの高圧ポート圧力を前記切換弁のほぼ中央に設けた中央ポートから前記中空２速スプールの中央に位置する第１半径方向穴より中空穴内に常に導くようにし、前記切換弁が低速側位置にあるときは前記油圧モータの高圧ポート圧力を前記第２小径スプールＢ及び第３小径スプールＤにみに作用するようにし、前記切換弁が高速側位置にあるときは前記高圧ポート圧力は、前記第１小径スプールＣ及び前記第２小径スプールＢに作用するようにしたので、従って、２速スプールに作用する前記高圧ポート圧力の受圧面積は、切換弁が低速側位置と高速側位置にいる時で異なっており、第３小径スプールＤは低速側位置の時のみ影響する。よって、第３小径スプールＤの径のみを変更することで、２速スプールが高速側位置に押し付けられる条件を変えずに、低速側位置に押し付けられる条件のみを変えることができる。その結果、第３小径スプールＤの径のみを大きくすることで、切換弁の切換設定圧力ＰHi→LO（高速→低速）を変えることなく、切換設定圧力ＰLO→Hi（低速→高速）を大きくすることができる。これにより、２つの切換設定圧力（高速→低速、低速→高速）の設定において、ヒステリシスを小さくでき、特に低速側位置から負荷力が下がり、高速側位置に戻るまでの応答性がよく、油圧モータの発進時などに於いてタイムラグがなく、スムーズな発進が可能となる。かつ２速スプール（主スプール）の径を大きくすることなく、又各小径スプール（各丸棒部材）の径を小さくすることなく、ヒステリシスを小さくした２速油圧モータの自動変速切換弁を提供するものとなった。
換言すると、本発明の２速油圧モータの自動変速切換弁において、メイン高圧が０の時にスプールを高速側位置に切換えるための最小外部パイロット圧力である最小切換圧力は、２速スプールの外部パイロット圧力の受圧面積と、スプリングとによって決まる構造となっている。つまり、２速スプールの外径から第１小径スプールＣの外径分を差し引いた面積とスプリングによって最小切換圧力が決まる。第１小径スプールＣの外径の面積分だけ、２速スプールに作用する外部パイロット圧力を受ける面積を小さくでき、２速スプールの径やスプリングを変更することなく最小切換圧力を大きくした２速油圧モータの自動変速切換弁となり、低作動油温時など実機の油圧システムの背圧影響が大きくても、スプールがかってに高速側位置に切り換わってしまう恐れがより少ない、２速油圧モータの自動変速切換弁を提供するものとなった。 According to the configuration of the present invention, in the present invention, the first radial hole located in the center of the hollow two-speed spool from the central port provided at the substantially central portion of the switching valve to the high pressure port pressure of the hydraulic motor that opposes the external pilot pressure. When the switching valve is at the low speed side position, the high pressure port pressure of the hydraulic motor is applied only to the second small diameter spool B and the third small diameter spool D, and the switching is performed. When the valve is in the high speed side position, the high pressure port pressure acts on the first small diameter spool C and the second small diameter spool B. Therefore, the pressure reception of the high pressure port pressure acting on the second speed spool The area is different when the switching valve is in the low speed side position and the high speed side position, and the third small diameter spool D is affected only when it is in the low speed side position. Therefore, by changing only the diameter of the third small-diameter spool D, it is possible to change only the condition for pressing the second speed spool to the low speed side position without changing the condition for pressing the second speed spool to the high speed side position. As a result, by increasing only the diameter of the third small-diameter spool D, the switching set pressure P LO → Hi (low speed → high speed) is maintained without changing the switching set pressure P Hi → LO (high speed → low speed) of the switching valve. Can be bigger. As a result, the hysteresis can be reduced in the setting of the two switching set pressures (high speed → low speed, low speed → high speed), and in particular, the responsiveness until the load force decreases from the low speed side position and returns to the high speed side position is good. There is no time lag when starting, and smooth starting is possible. An automatic transmission switching valve for a two-speed hydraulic motor with reduced hysteresis without increasing the diameter of the two-speed spool (main spool) and without decreasing the diameter of each small-diameter spool (each round bar member) is provided. It became a thing.
In other words, in the automatic transmission switching valve of the second speed hydraulic motor of the present invention, the minimum switching pressure, which is the minimum external pilot pressure for switching the spool to the high speed side position when the main high pressure is 0, is the external pilot pressure of the second speed spool. The structure is determined by the pressure receiving area and the spring. That is, the minimum switching pressure is determined by the area obtained by subtracting the outer diameter of the first small-diameter spool C from the outer diameter of the second speed spool and the spring. The second speed hydraulic pressure in which the area for receiving the external pilot pressure acting on the second speed spool can be reduced by the area of the outer diameter of the first small diameter spool C, and the minimum switching pressure is increased without changing the diameter or spring of the second speed spool. It is an automatic gear changeover valve for the motor. Even if the back pressure of the actual hydraulic system is large, such as when the hydraulic oil temperature is low, the spool is less likely to switch to the high-speed position before the automatic operation of the 2-speed hydraulic motor. Provided a gear change valve.

好ましくは、前記第３小径スプールＤは２個のランドを有し、前記切換弁が高速側位置にあるときは、前記外部パイロット圧力と対抗する油圧モータの高圧ポート圧力は、前記切換弁の中央ポートから前記第３小径スプールＤの２個のランド間に設けられた２速スプールの第２半径方向穴と前記第１小径スプールＣ内方と連通する第３小径スプールＤ内の油路とを介して、前記第１小径スプールＣ内方に作用し、かつそれと隣接する前記第３小径スプールＤの外方端面に作用すると共に、前記中空２速スプールの中央に位置する第１半径方向穴より中空穴内に常に導かれた前記油圧モータの高圧ポート圧力が前記第２小径スプールＢの内方端面とそれと対向する前記第３小径スプールＤの端面に作用するようにされている。   Preferably, the third small diameter spool D has two lands, and when the switching valve is in the high speed side position, the high pressure port pressure of the hydraulic motor that opposes the external pilot pressure is the center of the switching valve. A second radial hole of a second speed spool provided between the two lands of the third small diameter spool D from the port and an oil passage in the third small diameter spool D communicating with the inside of the first small diameter spool C. Through the first radial hole located at the center of the hollow second-speed spool, acting on the inner side of the first small-diameter spool C and acting on the outer end surface of the third small-diameter spool D adjacent thereto. The high pressure port pressure of the hydraulic motor, which is always guided into the hollow hole, acts on the inner end surface of the second small diameter spool B and the end surface of the third small diameter spool D facing it.

さらに好ましくは、前記高圧ポート圧力が前記外部パイロット圧力より小さいとき、前記外部パイロット圧力の作用によって前記第１小径スプールＣが前記２速スプール内側方向へ押し付けられ、前記第１小径スプールＣは前記第３小径スプールＤ及び第２小径スプールＢを介して付勢され、前記第１小径スプールＣに作用する力は前記２速スプールを高速側位置に押し付ける力とはならないようにされ、この位置では、外部パイロット圧力のの作用以外の低作動油温時など実機の油圧システムの背圧に影響されず、スプールがかってに高速側位置に切り換わってしまう恐れがさらに少ない、２速油圧モータの自動変速切換弁を提供するものとなった。   More preferably, when the high pressure port pressure is smaller than the external pilot pressure, the first small diameter spool C is pressed inwardly of the second speed spool by the action of the external pilot pressure, and the first small diameter spool C is 3 The force is applied through the small-diameter spool D and the second small-diameter spool B, and the force acting on the first small-diameter spool C is not forced to press the second-speed spool against the high-speed side position. Automatic shifting of a 2-speed hydraulic motor that is not affected by the back pressure of the actual hydraulic system, such as when the hydraulic oil temperature is low except for the effect of external pilot pressure, and that the spool will never switch to the high-speed position. Provided a switching valve.

また好ましくは、前記切換弁が低速側位置にあるときは、前記油圧モータの速度切替コントロールピストンの加圧室はドレンに連通され、前記切換弁が高速側位置にあるときは、前記油圧モータの速度切替コントロールピストンの加圧室は前記油圧モータの高圧ポート圧力と連通するようにされている。   Preferably, when the switching valve is in the low speed side position, the pressurizing chamber of the speed switching control piston of the hydraulic motor is connected to the drain, and when the switching valve is in the high speed side position, The pressure chamber of the speed switching control piston is in communication with the high pressure port pressure of the hydraulic motor.

本発明を実施するための最良の形態の一例を図１及び図２参照して説明する。図１は発明を実施するための最良の形態の２速油圧モータの自動変速切換弁が低速側位置にあるときの概略断面図を含む油圧回路図、図２は図１の同切換弁が高速側位置にあるときの概略断面図を含む油圧回路図を示す。図１に示すように、２速油圧モータ１の低速状態と高速状態を切換える自動変切換弁７は、ハウジング４（図２で点線で一部を示す）内に両端がプラグ５、６により閉じられた大径スプール穴15に軸方向に移動可能に嵌合された中空の２速スプール10と、２速スプール10両端及び中間に設けられた第１、第２及び第３の小径スプール穴16、17、23に軸方向に移動可能に嵌合された第１小径スプールＣ、第２小径スプールＢ及び第３小径スプールＤと、２速スプール10の中空穴肩部19と第２小径スプールＢとの間を離隔する方向に付勢するスプリング８と、を有する。第１小径スプールＣ及びそれと隣接する２速スプールの外方端部にはパイロット圧力室21が形成され、外部パイロット圧力ＰP が導かれ、外部パイロット圧力ＰP と対抗する油圧モータ１の高圧ポート圧力ＰA ・ B を切換弁７のほぼ中央に設けた中央ポートA.B から２速スプール10の中央に位置する半径方向穴18より中空穴内20に常に導くようにしている。高圧ポート圧力ＰA ・ B が第１切替設定圧ＰHi→LOより高く切換弁７が低速側位置にあるときは高圧ポート圧力 ＰA ・ B を第２小径スプールＢ及び第３小径スプールＤ及び前記第２小径スプールＢに作用するようにし、高圧ポート圧力ＰA ・ B が第２切替設定圧ＰLO→Hiより低く切換弁７が高速側位置にあるときは高圧ポート圧力ＰA ・ B は、第１小径スプールＣと第２小径スプールＢの内方端面とに対し作用するようにし、第１小径スプールＣの径D3を第２小径スプールＢの径D2より小に、かつ第３小径スプールＤの径D4より大にした。 An example of the best mode for carrying out the present invention will be described with reference to FIGS. FIG. 1 is a hydraulic circuit diagram including a schematic cross-sectional view when an automatic transmission switching valve of a two-speed hydraulic motor of the best mode for carrying out the invention is at a low speed side position, and FIG. The hydraulic circuit diagram containing a schematic sectional drawing when it exists in a side position is shown. As shown in FIG. 1, an automatic changeover switching valve 7 for switching between a low speed state and a high speed state of a two-speed hydraulic motor 1 is closed by plugs 5 and 6 in a housing 4 (partially indicated by a dotted line in FIG. 2). A hollow two-speed spool 10 fitted in the large-diameter spool hole 15 so as to be movable in the axial direction, and first, second and third small-diameter spool holes 16 provided at both ends and in the middle. , 17 and 23 are fitted to the first small-diameter spool C, the second small-diameter spool B, the third small-diameter spool D, and the hollow hole shoulder 19 of the second-speed spool 10 and the second small-diameter spool B. And a spring 8 for biasing in a direction to separate them from each other. A pilot pressure chamber 21 is formed at the outer end of the first small-diameter spool C and the adjacent second speed spool, and the external pilot pressure P P is guided to the high pressure port of the hydraulic motor 1 that opposes the external pilot pressure P P. The pressure P A / B is always led from the central port AB provided at substantially the center of the switching valve 7 to the hollow hole 20 through the radial hole 18 located at the center of the second speed spool 10. When the high pressure port pressure P A / B is higher than the first switching set pressure P Hi → LO and the switching valve 7 is in the low speed position, the high pressure port pressure P A / B is changed to the second small diameter spool B and the third small diameter spool D and When the high pressure port pressure P A · B is lower than the second switching set pressure P LO → Hi so as to act on the second small diameter spool B, the high pressure port pressure P A · B is The first small-diameter spool C and the inner end surface of the second small-diameter spool B are acted on, the diameter D3 of the first small-diameter spool C is smaller than the diameter D2 of the second small-diameter spool B, and the third small-diameter spool. It was made larger than the diameter D4 of D.

このため、第３小径スプールＤは２個のランド 24、25を有し、切換弁７が高速側位置にあるときは、外部パイロット圧力ＰP と対抗する油圧モータの高圧ポート圧力ＰA ・ B は、切換弁の中央ポート A.Bから第３小径スプールＤの２個のランド 24、25間に設けられた２速スプール10の第２半径方向穴26と第１小径スプールＣ内方と連通する第３小径スプールＤ内の油路27を介して、第１小径スプールＣ内方端面に作用し、かつそれと隣接する第３小径スプールＤの端面に作用すると共に、中空２速スプール10の中央に位置する第１半径方向穴18より中空穴20内に常に導かれた油圧モータの高圧ポート圧力ＰA ・ B が第２小径スプールＢの内方端面とそれと対向する第３小径スプールＤの端面28に作用するようにされている。 Therefore, the third small-diameter spool D has two lands 24 and 25, when the switching valve 7 is located at the high speed side position, the high pressure port pressure of the hydraulic motor against the external pilot pressure P P P A · B Is connected to the second radial hole 26 of the second-speed spool 10 provided between the two lands 24, 25 of the third small-diameter spool D from the central port AB of the switching valve and to the inside of the first small-diameter spool C. 3 acts on the inner end face of the first small diameter spool C via the oil passage 27 in the small diameter spool D, acts on the end face of the third small diameter spool D adjacent thereto, and is located at the center of the hollow second speed spool 10 third diameter spool D of the end face 28 high-pressure port pressure P a · B always guided hydraulic motor in the hollow hole 20 than the first radial bore 18 which therewith opposite the inner end face of the second small diameter spool B to It is supposed to work.

次に作動について説明すると、図１は油圧モータ１に作用する負荷高圧ポート圧力ＰA ・ B が第１切替設定圧ＰHi→LOより高く、切換弁７が低速側位置にある場合を示し、切換弁７には、油圧ポンプ13の圧油が方向切替弁12、カウンターバランス弁11を通って油圧モータ１の高圧ポートの圧力ＰA ・ B が、中央ポート A.Bから２速スプール10の半径方向穴18より中空穴内20に流入し、スプールＢを図１でみ右方向へ、スプールＤを同左方向へ押し付けている。これにより、低速側位置にある２速スプール10に作用する力ＦA ・ B は、ＦA ・ B ＝ＰA ・ B ×π／４（Ｄ2 2 −Ｄ4 2 ）となり、Ｄ2 ＞Ｄ4 であるから、２速スプール10を左方向へ押す力となる。一方、外部パイロット圧力ＰP は、２速スプールの左端ポートに導かれており、２速スプール10に作用する力は、Ｄ1 ＞Ｄ3 であるから、ＦP ＝ＰP ×π／４（Ｄ1 2 −Ｄ3 2 ）となり、２速スプール10を右方向へ押す力となる。又、スプリング８は、２速スプール10を左方向へ押す力ＦSPとなっている。図１の場合は、油圧モータに作用する負荷が大きく（＝ＰA ・ B が大きい）、２速スプール10に作用する力ＦP は、ＦP ＜ＦA ・ B ＋ＦSPとなり、２速スプールが左方向へ押し付けられる。この時、油圧モータ１のコントロールピストン２内圧力ＰCPは、シャトル弁３を介して、切換弁 7のポートＡ''又はポートＢ''からＤＲポートへ通じており、油圧モータ１は低速側位置になる。油圧モータ１に作用する負荷が小さくなり、高圧ポート圧力ＰA ・ B が第２切替設定圧ＰLO→Hiより低くなると、ＦA ・ B が小さくなり、ＦP ＞ＦA ・ B ＋ＦSPとなって、２速スプール10が右方向へ押し付けられ、図２の状態になる。この時、コントロールピストン２の加圧室内圧力ＰCPはシャトル弁３を介して、切換弁 7のポートＡ''又はポートＢ''から、ポートＡ‘又はポートＢ’へ通じ高圧ポート圧力ＰA ・ B に通じている。これにより、油圧モータ１の負荷圧力Ｐ' A 又はＰ' B が切換弁 7とシャトル弁３を通して、コントロールピストン２の加圧室へ流入し、油圧モータ１は高速側位置となる。 Next, the operation will be described. FIG. 1 shows a case where the load high pressure port pressure P A / B acting on the hydraulic motor 1 is higher than the first switching set pressure P Hi → LO , and the switching valve 7 is at the low speed side position. the switching valve 7, the pressure oil is direction switching valve 12 of the hydraulic pump 13, the pressure P a · B of the high pressure port of the hydraulic motor 1 through the counterbalance valve 11, the radial second speed spool 10 from the central port AB The air flows into the hollow hole 20 from the hole 18, and the spool B is pressed to the right in FIG. 1, and the spool D is pressed to the left. As a result, the force F A · B acting on the second speed spool 10 at the low speed side position becomes F A · B = P A · B × π / 4 (D 2 2 −D 4 2 ), and D 2 > D Since it is 4 , it becomes the force which pushes the 2-speed spool 10 to the left direction. On the other hand, the external pilot pressure P P is guided to the left end port of the 2-speed spool, and the force acting on the 2-speed spool 10 is D 1 > D 3 , so that F P = P P × π / 4 ( D 1 2 -D 3 2 ), which is the force that pushes the second speed spool 10 to the right. The spring 8 has a force F SP that pushes the second speed spool 10 leftward. In the case of FIG. 1, the load acting on the hydraulic motor is large (= P A · B is large), and the force F P acting on the second speed spool 10 is F P <F A · B + F SP . Is pushed to the left. At this time, the pressure P CP in the control piston 2 of the hydraulic motor 1 is connected to the DR port from the port A ″ or the port B ″ of the switching valve 7 via the shuttle valve 3. Become position. Decreases the load acting on the hydraulic motor 1, when the high-pressure port pressure P A · B becomes lower than the second switching set pressure P LO → Hi, F A · B is reduced, and F P> F A · B + F SP Thus, the second speed spool 10 is pushed rightward, and the state shown in FIG. 2 is obtained. At this time, the pressurized chamber pressure P CP of the control piston 2 passes from the port A ″ or port B ″ of the switching valve 7 to the port A ′ or port B ′ via the shuttle valve 3, and the high pressure port pressure P A. -Leads to B. As a result, the load pressure P ′ A or P ′ B of the hydraulic motor 1 flows into the pressurizing chamber of the control piston 2 through the switching valve 7 and the shuttle valve 3, and the hydraulic motor 1 is in the high speed side position.

図２は高圧ポート圧力ＰA ・ B が第２切替設定圧ＰLO→Hiより低く切換弁７が高速側位置にある場合を示し、油圧モータ１に作用する負荷が小さく（＝ＰA ・ B が小さい）、油圧モータ１の高圧ポートの圧力ＰA ・ B が、カウンターバランス弁11を通って中央ポート A.Bから２速スプール10の半径方向穴18より中空穴内20に流入し、スプールＢを図２で見て右方向へ、スプールＤを同左方向へ押し付けている。外部パイロット圧力ＰP と対抗する油圧モータの高圧ポート圧力ＰA ・ B は、切換弁の中央ポート A.Bから第３小径スプールＤの２個のランド 24、25間に設けられた２速スプール10の第２半径方向穴26と第１小径スプールＣ内方と連通する第３小径スプールＤ内の油路27を介して、第１小径スプールＣ内方に作用し、かつ第３小径スプールＤの外方端面に作用すると共に、中空２速スプール10の中央に位置する第１半径方向穴18より中空穴20内に常に導かれた油圧モータの高圧ポート圧力ＰA ・ B が第２小径スプールＢの内方端面とそれと対向する前記第３小径スプールＤの端面28に作用するようにされているので、第３小径スプールＤは、左右に油圧モータの高圧ポート圧力ＰA ・ B が作用しているため、左右どちらかの方向にも押し付けられない。これにより、Ｄ2 ＞Ｄ3 であるので、切換弁７が高速側位置にあるときの２速スプール10に作用する力Ｆ' A ・ B は、Ｆ' A ・ B ＝ＰA ・ B ×π／４（Ｄ2 2 −Ｄ3 2 ）となり、２速スプール10を左方向へ押す力となる。一方、外部パイロット圧力ＰP とスプリングの力ＦSPにより、２速スプール10には、右方向への外部パイロット圧力ＰP による力ＦP と、左方向への力スプリングによる力ＦSPが作用している、図２の場合は、油圧モータ１に作用する負荷が小さく（＝ＰA ・ B が小さい）、外部パイロット圧力ＰP による力ＦP は、ＦP ＞Ｆ' A ・ B ＋ＦSPとなり、２速スプール10が右に押し付けられている。この時、油圧モータ１は高速位置となる。 FIG. 2 shows a case where the high pressure port pressure P A · B is lower than the second switching set pressure P LO → Hi and the switching valve 7 is in the high speed side position, and the load acting on the hydraulic motor 1 is small (= P A · B The pressure P A / B of the high pressure port of the hydraulic motor 1 flows from the center port AB into the hollow hole 20 through the radial hole 18 of the second speed spool 10 through the counter balance valve 11, and the spool B is shown in FIG. The spool D is pressed in the right direction as viewed in FIG. The high pressure port pressure P A / B of the hydraulic motor that opposes the external pilot pressure P P is that of the second speed spool 10 provided between the two lands 24, 25 of the third small diameter spool D from the central port AB of the switching valve. It acts on the inside of the first small diameter spool C via the oil passage 27 in the third small diameter spool D communicating with the second radial hole 26 and the inside of the first small diameter spool C, and outside the third small diameter spool D. together acting Katatan surface, always led hydraulic motor of the high-pressure port pressure P a · B than the first radial hole 18 in the hollow bore 20 located in the center of the hollow second speed spool 10 of the second small diameter spool B since it is adapted to act on the third small-diameter spool D of the end surface 28 of the same facing the inner end face, a third small diameter spool D is the hydraulic motor pressure port pressure P a · B acting on the left and right Therefore, it cannot be pressed in either the left or right direction. Thus, since D 2 > D 3 , the force F ′ A · B acting on the second speed spool 10 when the switching valve 7 is at the high speed side position is F ′ A · B = P A · B × π / 4 (D 2 2 -D 3 2 ), which is the force that pushes the second speed spool 10 leftward. On the other hand, the external pilot pressure P P and the spring force F SP, the second speed spool 10, the force F P by the external pilot pressure P P in the right direction, the force F SP by the force the spring leftward acts and which, in the case of FIG. 2, the load acting on the hydraulic motor 1 is small (= a small P a · B), the force F P by the external pilot pressure P P is, F P> F 'a · B + F SP becomes The 2-speed spool 10 is pressed to the right. At this time, the hydraulic motor 1 is in a high speed position.

油圧モータ１に作用する負荷高圧ポート圧力ＰA ・ B が第１切替設定圧ＰHi→LOより高くなると、上記高速位置での２速スプール10に作用する力Ｆ' A ・ B が大きくなり、ＦP ＜Ｆ' A ・ B ＋ＦSPとなって、２速スプール10が左方向へ押し付けられ、図１の状態になる。この時、油圧モータ１は低速位置となる。以上より、２速スプール10に作用する力のつり合い式は、「ＦP ＝ＦA ・ B ＋ＦSP」と「ＦP ＝Ｆ' A ・ B ＋ＦSP」の２つの式で表され、切換弁７のヒステリシスは、低速側位置にある２速スプール10に作用する力ＦA ・ B と高速位置にある２速スプール10に作用する力Ｆ' A ・ B の差と、スプリング定数と２速スプール10のオーバーラップ量により設けられる。ＦA ・ B とＦ' A ・ B の差によって設けられる切換弁のヒステリシスは、ＦA ・ B ＝ＰA ・ B ×π／４（Ｄ2 2 −Ｄ4 2 ）、Ｆ' A ・ B ＝ＰA ・ B ×π／４（Ｄ2 2 −Ｄ3 2 ）なので、Ｄ3 とＤ4 の差によって決まる。Ｄ4 の外径のみを変更した場合、ＦP 、ＦSPおよびＦ' A ・ B に変化はなく、ＦA ・ B のみの変化となり、切換弁の切換圧力ＰHi→LO（高速→低速）は変わらずに、切換圧力ＰLO→Hi（低速→高速）のみ変わる。 When the load high pressure port pressure P A / B acting on the hydraulic motor 1 becomes higher than the first switching set pressure P Hi → LO , the force F ′ A · B acting on the second speed spool 10 at the high speed position increases. F P <F ′ A · B + F SP is satisfied, and the second-speed spool 10 is pushed leftward to be in the state shown in FIG. At this time, the hydraulic motor 1 is in the low speed position. Thus, balance equation of the force acting on the second speed spool 10 is represented by two equations with "F P = F A · B + F SP ", "F P = F 'A · B + F SP ", the switching valve 7 hysteresis is the difference between the force F A · B acting on the second speed spool 10 at the low speed position and the force F ′ A · B acting on the second speed spool 10 at the high speed position, the spring constant and the second speed spool. Provided with an overlap amount of 10. The hysteresis of the switching valve provided by the difference between F A · B and F ′ A · B is F A · B = P A · B × π / 4 (D 2 2 −D 4 2 ), F ′ A · B = Since P A · B × π / 4 (D 2 2 −D 3 2 ), it is determined by the difference between D 3 and D 4 . When only the outer diameter of D 4 is changed, there is no change in F P , F SP and F ' A · B , only F A · B is changed, and the switching pressure P Hi → LO (high speed → low speed) Does not change, only the switching pressure P LO → Hi (low speed → high speed) changes.

図３は、図１の２速油圧モータの自動変速切換弁が低速側位置にあり、第１小径スプールＣが２速スプール10の内側方向（図で見て右方向）に押し付けられた状態である。高圧ポート圧力ＰA ・ B が外部パイロット圧力ＰP より小さいとき、外部パイロット圧力ＰP の作用によって第１小径スプールＣが２速スプール10内側方向へ押し付けられ、第１小径スプールＣは第３小径スプールＤ及び第２小径スプールＢを介して付勢され、第１小径スプールＣに作用する力は２速スプールを高速側位置に押し付ける力とはならない。このため、この位置では、外部パイロット圧力の作用以外の低作動油温時など実機の油圧システムの背圧に影響されず、スプールがかってに高速側位置に切り換わってしまう恐れがさらに少ない、２速油圧モータの自動変速切換弁を提供するものとなった。
〔本発明の最良の実施形態の効果〕 FIG. 3 shows a state in which the automatic transmission switching valve of the two-speed hydraulic motor in FIG. 1 is in the low-speed position and the first small-diameter spool C is pressed inward (rightward in the drawing) of the second-speed spool 10. is there. When the high-pressure port pressure P A · B smaller than the external pilot pressure P P, pressed first small diameter spool C by the action of an external pilot pressure P P is the second speed spool 10 inwardly, the first small diameter spool C is third diameter The force that is urged through the spool D and the second small-diameter spool B and acts on the first small-diameter spool C does not become a force that presses the second-speed spool to the high-speed side position. For this reason, at this position, there is less possibility of the spool being switched to the high speed side position without being affected by the back pressure of the actual hydraulic system, such as at low hydraulic oil temperature other than the action of the external pilot pressure. An automatic transmission switching valve for a high speed hydraulic motor is provided.
[Effect of Best Embodiment of the Present Invention]

上記の本発明の最良の実施形態から、本発明では、外部パイロット圧力と対抗する油圧モータの高圧ポート圧力を前記切換弁のほぼ中央に設けた中央ポートから前記中空２速スプールの中央に位置する第１半径方向穴より中空穴内に常に導くようにし、前記切換弁が低速側位置にあるときは前記油圧モータの高圧ポート圧力を前記第２小径スプールＢ及び第３小径スプールＤにみに作用するようにし、前記切換弁が高速側位置にあるときは前記高圧ポート圧力は、前記第１小径スプールＣ及び前記第２小径スプールＢの各内方端面に作用するようにしたので、従って、２速スプールに作用する前記高圧ポート圧力の受圧面積は、切換弁が低速側位置と高速側位置にいる時で異なっており、第３小径スプールＤは低速側位置の時のみ影響する。よって、第３小径スプールＤの径のみを変更することで、２速スプールが高速側位置に押し付けられる条件を変えずに、低速側位置に押し付けられる条件のみを変えることができる。その結果、第３小径スプールＤの径のみを大きくすることで、切換弁の切換設定圧力ＰHi→LO（高速→低速）を変えることなく、切換設定圧力ＰLO→Hi（低速→高速）を大きくすることができる。これにより、２つの切換設定圧力（高速→低速、低速→高速）の設定において、ヒステリシスを小さくでき、特に低速側位置から負荷力が下がり、高速側位置に戻るまでの応答性がよく、油圧モータの発進時などに於いてタイムラグがなく、スムーズな発進が可能となる。かつ２速スプール（主スプール）の径を大きくすることなく、又各小径スプール（各丸棒部材）の径を小さくすることなく、ヒステリシスを小さくした２速油圧モータの自動変速切換弁を提供するものとなった。換言すると、本発明の２速油圧モータの自動変速切換弁において、メイン高圧が０の時にスプールを高速側位置に切換えるための最小外部パイロット圧力である最小切換圧力は、２速スプールの外部パイロット圧力の受圧面積と、スプリングとによって決まる構造となっている。つまり、２速スプールの外径から第１小径スプールＣの外径分を差し引いた面積とスプリングによって最小切換圧力が決まる。第１小径スプールＣの外径の面積分だけ、２速スプールに作用する外部パイロット圧力を受ける面積を小さくでき、２速スプールの径やスプリングを変更することなく最小切換圧力を大きくした２速油圧モータの自動変速切換弁となり、低作動油温時など実機の油圧システムの背圧影響が大きくても、スプールがかってに高速側位置に切り換わってしまう恐れがより少ない、２速油圧モータの自動変速切換弁を提供するものとなった。 From the above-mentioned best mode of the present invention, in the present invention, the high pressure port pressure of the hydraulic motor that opposes the external pilot pressure is located at the center of the hollow two-speed spool from the central port provided at the approximate center of the switching valve. When the switching valve is at the low speed side position, the high pressure port pressure of the hydraulic motor acts only on the second small diameter spool B and the third small diameter spool D. Thus, when the switching valve is at the high speed side position, the high pressure port pressure acts on the inner end surfaces of the first small diameter spool C and the second small diameter spool B. The pressure receiving area of the high pressure port pressure acting on the spool differs when the switching valve is at the low speed side position and the high speed side position, and the third small diameter spool D is affected only at the low speed side position. Therefore, by changing only the diameter of the third small-diameter spool D, it is possible to change only the condition for pressing the second speed spool to the low speed side position without changing the condition for pressing the second speed spool to the high speed side position. As a result, by increasing only the diameter of the third small-diameter spool D, the switching set pressure P LO → Hi (low speed → high speed) is maintained without changing the switching set pressure P Hi → LO (high speed → low speed) of the switching valve. Can be bigger. As a result, the hysteresis can be reduced in the setting of the two switching set pressures (high speed → low speed, low speed → high speed), and in particular, the responsiveness until the load force decreases from the low speed side position and returns to the high speed side position is good. There is no time lag when starting, and smooth starting is possible. An automatic transmission switching valve for a two-speed hydraulic motor with reduced hysteresis without increasing the diameter of the two-speed spool (main spool) and without decreasing the diameter of each small-diameter spool (each round bar member) is provided. It became a thing. In other words, in the automatic transmission switching valve of the second speed hydraulic motor of the present invention, the minimum switching pressure, which is the minimum external pilot pressure for switching the spool to the high speed side position when the main high pressure is 0, is the external pilot pressure of the second speed spool. The structure is determined by the pressure receiving area and the spring. That is, the minimum switching pressure is determined by the area obtained by subtracting the outer diameter of the first small-diameter spool C from the outer diameter of the second speed spool and the spring. The second speed hydraulic pressure in which the area for receiving the external pilot pressure acting on the second speed spool can be reduced by the area of the outer diameter of the first small diameter spool C, and the minimum switching pressure is increased without changing the diameter or spring of the second speed spool. It is an automatic gear changeover valve for the motor. Even if the back pressure of the actual hydraulic system is large, such as when the hydraulic oil temperature is low, the spool is less likely to switch to the high-speed position before the automatic operation of the 2-speed hydraulic motor. Provided a gear change valve.

本発明の最良の実施形態の２速油圧モータの自動変速切換弁が低速側位置にあるときの概略断面図を含む油圧回路図を示す。1 is a hydraulic circuit diagram including a schematic cross-sectional view when an automatic transmission switching valve of a two-speed hydraulic motor according to a best embodiment of the present invention is in a low-speed position. 図１の２速油圧モータの自動変速切換弁が高速側位置にあるときの概略断面図を含む油圧回路図を示す。FIG. 2 is a hydraulic circuit diagram including a schematic cross-sectional view when the automatic transmission switching valve of the two-speed hydraulic motor of FIG. 図１の２速油圧モータの自動変速切換弁が低速側位置にあり、第１小径スプールＣが２速スプール内側方向へ押し付けられ、第１小径スプールＣは第３小径スプールＤ及び第２小径スプールＢを介して付勢されたときの概略断面図を含む油圧回路図を示す。The automatic transmission switching valve of the two-speed hydraulic motor in FIG. 1 is in the low-speed position, the first small diameter spool C is pressed inwardly of the second speed spool, and the first small diameter spool C is the third small diameter spool D and the second small diameter spool. The hydraulic circuit diagram containing a schematic sectional drawing when energized via B is shown.

符号の説明Explanation of symbols

１・・２速油圧モータ ２・・コントロールピストン ３・・シャトル弁
４・・ハウジング ７・・自動変切換弁 ８・・スプリング
10・・２速スプール 15・・大径スプール穴 16・・第１の小径スプール穴
17・・第２の小径スプール穴 19・・２速スプールの中空穴肩部
20・・２速スプールの中空穴 21・・パイロット圧力室
23・・第３の小径スプール穴 24、25・・第３小径スプールＤの２個のランド
26・・２速スプール10の第２半径方向穴 27・・第３小径スプールＤ内の油路
28・・第２小径スプールＢ内方端面と対向する第３小径スプールＤの端面
A.B ・・中央ポート Ｂ・・第２小径スプールＢ Ｃ・・第１小径スプールＣ
Ｄ・・第３小径スプールＤ D2・・第２小径スプールＢの径
D3・・第１小径スプールＣの径 D4・・第３小径スプールＤの径
ＰA ・ B ・・高圧ポート圧力 ＰP ・・外部パイロット圧力 1 ・ ・ 2-speed hydraulic motor 2 ・ ・ Control piston 3 ・ ・ Shuttle valve 4 ・ ・ Housing 7 ・ ・ Automatic changeover valve 8 ・ ・ Spring
10. ・ 2 speed spool 15 ・ ・ Large diameter spool hole 16 ・ ・ First small diameter spool hole
17 ・ ・ Second small diameter spool hole 19 ・ ・ Hollow hole shoulder of 2nd speed spool
20 ・ ・ Hollow hole of 2-speed spool 21 ・ ・ Pilot pressure chamber
23 ・ ・ Third small diameter spool hole 24, 25 ・ ・ Two lands of third small diameter spool D
26 ··· Second radial hole of second speed spool 27 · · Oil passage in third small diameter spool D
28..End surface of the third small-diameter spool D facing the inner end surface of the second small-diameter spool B
AB ・ ・ Central port B ・ ・ Second small diameter spool B C ・ ・ First small diameter spool C
D ・ ・ 3rd small diameter spool D D2 ・ ・ The diameter of 2nd small diameter spool B
D3 · · diameter P A · B · · pressure port pressure diameter D4 · · third small diameter spool D of the first small diameter spool C P P · · External pilot pressure

Claims (4)

２速油圧モータの低速状態と高速状態を切換える自動変速切換弁において、前記切換弁はハウジング内に両端が閉じられた大径スプール穴に軸方向に移動可能に嵌合された中空の２速スプールと、２速スプール両端と中間に設けられた第１、第２及び第３の小径スプール穴に軸方向に移動可能に嵌合された第１小径スプールＣ、第２小径スプールＢ及び第３小径スプールＤと、前記２速スプールの中空穴肩部と前記第２小径スプールＢとの間を離隔する方向に付勢するスプリングと、を有し、前記第１小径スプールＣ及びそれと隣接する２速スプールの外方端部には外部パイロット圧力が導かれ、外部パイロット圧力と対抗する油圧モータの高圧ポート圧力を前記切換弁のほぼ中央に設けた中央ポートから前記中空２速スプールの中央に位置する第１半径方向穴より中空穴内に常に導くようにし、前記高圧ポート圧力が第１切替設定圧力より高く前記切換弁が低速側位置にあるときは前記高圧ポート圧力を前記第２小径スプールＢ及び第３小径スプールＤに作用するようにし、前記高圧ポート圧力が第２切替設定圧力より低く前記切換弁が高速側位置にあるときは前記高圧ポート圧力は、前記第１小径スプールＣの内方端面及び前記第２小径スプールＢの内方端面に作用するようにし、前記第１小径スプールＣの径D3を第２小径スプールＢの径D2より小に、かつ前記第３小径スプールＤの径D4より大にしたことを特徴とする２速油圧モータの自動変速切換弁。   In an automatic transmission switching valve that switches between a low speed state and a high speed state of a two-speed hydraulic motor, the switching valve is a hollow two-speed spool that is fitted in a large-diameter spool hole whose both ends are closed in the housing so as to be movable in the axial direction. And a first small-diameter spool C, a second small-diameter spool B, and a third small-diameter that are movably fitted in first, second, and third small-diameter spool holes provided at both ends and in the middle of the second-speed spool. A spool D, and a spring urging in a direction separating the hollow hole shoulder portion of the second speed spool and the second small diameter spool B, and the first small diameter spool C and the second speed adjacent thereto. An external pilot pressure is guided to the outer end of the spool, and the high pressure port pressure of the hydraulic motor, which opposes the external pilot pressure, is positioned at the center of the hollow two-speed spool from the central port provided substantially at the center of the switching valve. When the high pressure port pressure is higher than the first switching set pressure and the switching valve is at the low speed side position, the high pressure port pressure is set to the second small diameter spool B and When the high pressure port pressure is lower than the second switching set pressure and the switching valve is at the high speed side position, the high pressure port pressure is applied to the third small diameter spool D. And acting on the inner end surface of the second small diameter spool B, the diameter D3 of the first small diameter spool C is smaller than the diameter D2 of the second small diameter spool B and the diameter D4 of the third small diameter spool D. An automatic transmission switching valve for a two-speed hydraulic motor, characterized in that it is enlarged. 前記第３小径スプールＤは２個のランドを有し、前記切換弁が高速側位置にあるときは、前記外部パイロット圧力と対抗する油圧モータの高圧ポート圧力は、前記切換弁の中央ポートから前記第３小径スプールＤの２個のランド間に設けられた２速スプールの第２半径方向穴と前記第１小径スプールＣ内方と連通する第３小径スプールＤ内の油路とを介して、前記第１小径スプールＣ内方に作用し、かつそれと隣接する前記第３小径スプールＤの端面に作用すると共に、前記中空２速スプールの中央に位置する第１半径方向穴より中空穴内に常に導かれた前記油圧モータの高圧ポート圧力が前記第２小径スプールＢの内方端面とそれと対向する前記第３小径スプールＤの端面に作用するようにされたことを特徴とする請求項１記載の２速油圧モータの自動変速切換弁。   The third small diameter spool D has two lands, and when the switching valve is in the high speed side position, the high pressure port pressure of the hydraulic motor that opposes the external pilot pressure is from the central port of the switching valve. Via a second radial hole of a second speed spool provided between two lands of the third small diameter spool D and an oil passage in the third small diameter spool D communicating with the inside of the first small diameter spool C, Acts inwardly of the first small diameter spool C and acts on the end surface of the third small diameter spool D adjacent thereto, and is always guided into the hollow hole from the first radial hole located at the center of the hollow second speed spool. The high pressure port pressure of the hydraulic motor is applied to the inner end face of the second small diameter spool B and the end face of the third small diameter spool D facing the inner end face. Hydraulic speed Automatic transmission selector valve of over data. 前記高圧ポート圧力が前記外部パイロット圧力より小さいとき、前記外部パイロット圧力の作用によって前記第１小径スプールＣが前記２速スプール内側方向へ押し付けられ、前記第１小径スプールＣは前記第３小径スプールＤ及び第２小径スプールＢを介して付勢され、前記第１小径スプールＣに作用する力は前記２速スプールを高速側位置に押し付ける力とはならないようにされたことを特徴とする請求項１又は請求項２記載の２速油圧モータの自動変速切換弁。   When the high pressure port pressure is smaller than the external pilot pressure, the first small diameter spool C is pressed inwardly of the second speed spool by the action of the external pilot pressure, and the first small diameter spool C is the third small diameter spool D. And a force acting on the first small-diameter spool C so as not to press the second-speed spool against a high-speed side position. Alternatively, an automatic transmission switching valve for a two-speed hydraulic motor according to claim 2. 前記切換弁が低速側位置にあるときは、前記油圧モータの速度切替コントロールピストンの加圧室はドレンに連通され、前記切換弁が高速側位置にあるときは、前記油圧モータの速度切替コントロールピストンの加圧室は前記油圧モータの高圧ポート圧力と連通するようにしたことを特徴とする請求項１乃至請求項３のいずれか１に記載の２速油圧モータの自動変速切換弁。   When the switching valve is in the low speed side position, the pressurizing chamber of the speed switching control piston of the hydraulic motor is communicated with the drain, and when the switching valve is in the high speed side position, the speed switching control piston of the hydraulic motor. The automatic transmission switching valve for a two-speed hydraulic motor according to any one of claims 1 to 3, wherein the pressurizing chamber is in communication with a high pressure port pressure of the hydraulic motor.
JP2003409725A 2003-06-24 2003-12-09 Automatic transmission switching valve for 2-speed hydraulic motor Expired - Lifetime JP3863141B2 (en)

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DE102008058176A1 (en) 2007-11-20 2009-05-28 Robert Bosch Gmbh Valve device for use in hydrostatic traction drive of vehicle, has casing subjected to measuring surface with control pressure, where connection is interrupted between control pressure area and source of control pressure
WO2013018203A1 (en) * 2011-08-03 2013-02-07 トヨタ自動車株式会社 Switching valve
JP2015135026A (en) * 2014-01-17 2015-07-27 住友建機株式会社 Road paving machine
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Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102008058176A1 (en) 2007-11-20 2009-05-28 Robert Bosch Gmbh Valve device for use in hydrostatic traction drive of vehicle, has casing subjected to measuring surface with control pressure, where connection is interrupted between control pressure area and source of control pressure
WO2013018203A1 (en) * 2011-08-03 2013-02-07 トヨタ自動車株式会社 Switching valve
CN103717952A (en) * 2011-08-03 2014-04-09 丰田自动车株式会社 Switching valve
JP2015135026A (en) * 2014-01-17 2015-07-27 住友建機株式会社 Road paving machine
CN110906556A (en) * 2018-09-18 2020-03-24 芜湖美的厨卫电器制造有限公司 Water mixing device for water heater, water heater and water mixing method of water heater
CN110906556B (en) * 2018-09-18 2024-03-29 芜湖美的厨卫电器制造有限公司 Water mixing device for water heater, water heater and water mixing method of water heater

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