JP2010127457A - Structure of hydraulic unit - Google Patents

Structure of hydraulic unit Download PDF

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JP2010127457A
JP2010127457A JP2008306658A JP2008306658A JP2010127457A JP 2010127457 A JP2010127457 A JP 2010127457A JP 2008306658 A JP2008306658 A JP 2008306658A JP 2008306658 A JP2008306658 A JP 2008306658A JP 2010127457 A JP2010127457 A JP 2010127457A
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pressure
flow path
fluid
hydraulic
valve
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Hiromitsu Kawachi
宏充 河内
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Shimadzu Corp
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Shimadzu Corp
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Abstract

<P>PROBLEM TO BE SOLVED: To improve pressure loss performance in neutral by a simple structure, in a hydraulic unit including a plurality of stacked selector valves and a high-pressure flow passage for guiding a working fluid from a hydraulic supply source to a tank through the plurality of selector valves laid in a neutral state. <P>SOLUTION: In the structure of the hydraulic unit 3 including fluid control valves 5-7 that are the plurality of selector valves; the high-pressure flow passage 31 for guiding working fluid from a pump 1 that is the hydraulic supply source to the tank 9 through the fluid control valves 5-7 laid in the neutral state; and a parallel flow passage 32 branched from the high-pressure flow passage 31 to guide the working fluid to each of the fluid control valves 5-7, the fluid control valves 5-7 commonly using the high-pressure flow passage 31 and the parallel flow passage 32, the unit 3 further includes a diaphragm 81 that is a flow detection means for detecting a flow rate of the fluid passing through the fluid control valve 7 on the lowermost stream side via the high-pressure flow passage 31; and a control valve 82 which opens the parallel flow passage 32 to the tank 9 when a differential pressure between the front and rear of the diaphragm 81 exceeds a predetermined value. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

本発明は、複数の切替弁を有し、中立状態にある前記複数の切替弁を貫通し液圧供給源からの作動液をタンクに導く高圧流路と、この高圧流路から分岐させてなるパラレル流路とを使用する液圧ユニットの構造に関する。   The present invention includes a plurality of switching valves, a high-pressure channel that passes through the plurality of switching valves in a neutral state and guides hydraulic fluid from a hydraulic pressure supply source to a tank, and is branched from the high-pressure channel. The present invention relates to a structure of a hydraulic unit using a parallel flow path.

従来、複数の切替弁を有し、中立状態にある前記複数の切替弁を貫通し液圧供給源からの作動液をタンクに導く高圧流路と、この高圧流路から分岐させてなるパラレル流路とを使用する液圧ユニットが種々知られている。具体的には、このような液圧ユニットは、高圧流路が前記複数の切替弁を貫通し、非操作時には高圧流路がいずれの切替弁にも遮蔽されることなくタンクに接続している（例えば、特許文献１を参照）。この高圧流路の圧力損失はこの液圧ユニットの中立時圧力損失性能となるので、この圧力損失はできるだけ小さい方が望ましい。この圧力損失を小さくする方法として、従来、前記高圧流路の径を大きくすることが考えられてきている。
特願２００１−９９１０８号公報 Conventionally, there are a plurality of switching valves, a high-pressure channel that passes through the plurality of switching valves in a neutral state and guides hydraulic fluid from a hydraulic pressure supply source to a tank, and a parallel flow that is branched from the high-pressure channel Various hydraulic units that use roads are known. Specifically, in such a hydraulic unit, a high-pressure channel passes through the plurality of switching valves, and the high-pressure channel is connected to the tank without being shielded by any switching valve when not operated. (For example, see Patent Document 1). Since the pressure loss of the high-pressure channel becomes the neutral pressure loss performance of the hydraulic unit, it is desirable that the pressure loss be as small as possible. As a method for reducing this pressure loss, conventionally, increasing the diameter of the high-pressure flow path has been considered.
Japanese Patent Application No. 2001-99108

ところが、前記高圧流路の径を大きくすると、必然的に液圧ユニットの設置に必要なスペースや液圧ユニットは大型のものとなり、質量が大きくなる不具合や、機器配置の自由度が小さくなる不具合が発生する。   However, if the diameter of the high-pressure flow path is increased, the space and the hydraulic unit necessary for installing the hydraulic unit are inevitably large, resulting in a problem that the mass is increased and the degree of freedom in device arrangement is reduced. Occurs.

本発明はこのような課題を解決することを目的とする。   The present invention aims to solve such problems.

本発明に係る液圧ユニットの構造は、以上に述べた課題を解決すべく、複数の切替弁と、中立状態にある前記複数の切替弁を貫通し液圧供給源からの作動液をタンクに導く高圧流路と、この高圧流路から分岐させてなり前記各切替弁に作動液を導くためのパラレル流路とを具備し、前記複数の切替弁が前記高圧流路及び前記パラレル流路を共通に使用する型液圧ユニットの構造であって、高圧流路を経て最下流の切替弁を通過する流量を検出するための流量検出手段と、この流量検出手段が検出した前記流量が所定値を上回る場合にパラレル流路をタンクに開放する制御弁とをさらに具備することを特徴とする。   In order to solve the above-described problems, the structure of the hydraulic unit according to the present invention passes through a plurality of switching valves and the plurality of switching valves in a neutral state, and supplies hydraulic fluid from a hydraulic pressure supply source to the tank. A high-pressure channel for guiding, and a parallel channel for branching from the high-pressure channel to guide the working fluid to each of the switching valves, wherein the plurality of switching valves connect the high-pressure channel and the parallel channel. The structure of the mold hydraulic unit used in common, the flow rate detecting means for detecting the flow rate passing through the switching valve on the most downstream side through the high pressure flow path, and the flow rate detected by the flow rate detecting means is a predetermined value And a control valve that opens the parallel flow path to the tank when the flow rate exceeds the value.

このようなものであれば、高圧流路の流量が大きくなった際には、パラレル流路がタンクに開放されるので、作動液をタンクに導く経路として高圧流路を経る経路だけでなくパラレル流路を経る経路も利用される。従って高圧流路の径を大きくした場合と同様の効果を得ることができる。また、流量検出手段により高圧流路を経て中立状態にある最下流の切替弁を通過する流量を検出するようにしているので、各切替弁にパイロット通路を接続する等の複雑な構成を採用することなく、簡単な構成及び少ない部品点数で前記効果を得ることができる。   In such a case, when the flow rate of the high-pressure channel is increased, the parallel channel is opened to the tank, so that not only the path through the high-pressure channel but also the parallel channel as the path for guiding the working fluid to the tank. A route through the flow path is also used. Therefore, the same effect as when the diameter of the high-pressure channel is increased can be obtained. In addition, since the flow rate detection means detects the flow rate passing through the most downstream switching valve through the high-pressure flow path, a complicated configuration such as connecting a pilot passage to each switching valve is adopted. The above effect can be obtained with a simple configuration and a small number of parts.

本発明に係る液圧ユニットの構造によれば、高圧流路を経て中立状態にある最下流の切替弁を通過する流量を検出する流量検出手段を設け、この流量検出手段が検出した流量が大きくなった際にパラレル流路をタンクに開放するので、パラレル流路を高圧流路として使用し、高圧流路の径を大きくすることなく高圧流路の圧力損失を小さくすること、すなわち液圧ユニットの中立時圧力損失性能の向上を簡単な構成によって図ることができる。   According to the structure of the hydraulic unit according to the present invention, the flow rate detection means for detecting the flow rate passing through the most downstream switching valve in the neutral state via the high pressure flow path is provided, and the flow rate detected by the flow rate detection means is large. Since the parallel flow path is opened to the tank when it becomes, the parallel flow path is used as a high pressure flow path, and the pressure loss of the high pressure flow path is reduced without increasing the diameter of the high pressure flow path, that is, the hydraulic unit The neutral pressure loss performance can be improved with a simple configuration.

以下、本発明の一実施形態について述べる。   Hereinafter, an embodiment of the present invention will be described.

本実施形態に係る液圧回路Ｃは、図１に示すように、作動液を溜めておくためのタンク９と、このタンク９から作動液を送り出す液圧ポンプ１と、この液圧ポンプ１から作動液の供給を受ける優先弁機構２と、この優先弁機構２にスタックしてなるとともに、この優先弁機構２の余剰流出力口２ａから作動液の供給を受けるポンプ側ポート３ａ、及び作動液を吐出するタンク側ポート３ｂを有する液圧ユニット３とを具備する。   As shown in FIG. 1, the hydraulic circuit C according to the present embodiment includes a tank 9 for storing hydraulic fluid, a hydraulic pump 1 for sending hydraulic fluid from the tank 9, and a hydraulic pump 1 A priority valve mechanism 2 that receives the supply of the hydraulic fluid, a pump side port 3a that is stacked on the priority valve mechanism 2 and that receives the supply of the hydraulic fluid from the surplus flow output port 2a of the priority valve mechanism 2, and the hydraulic fluid And a hydraulic unit 3 having a tank side port 3b.

前記優先弁機構２は、フォークリフト等に用いられ、ステアリング機構と、複数の切替弁をスタックして形成した液圧ユニットとに作動液を供給するこの種の優先弁機構として周知のものと同様の構成を有する。すなわち、内部に優先弁本体２１等の種々のバルブを一体的に組み込んでなるもので、供給された作動液を優先流と余剰流とに分流するという優先分流機能を有し、前記液圧ポンプ１から吐出された高圧作動油の導入口たるポートＰと、タンク９に連通するタンクポートＴ１、Ｔ２と、図示しないステアリング操作補助回路に連通し、ステアリング操作された際に必要な作動液を優先して吐出するポートＰＦと、余剰の作動液を吐出する余剰流出力口２ａとを具備する。   The priority valve mechanism 2 is used for a forklift or the like, and is similar to a well-known type of this priority valve mechanism that supplies hydraulic fluid to a steering mechanism and a hydraulic unit formed by stacking a plurality of switching valves. It has a configuration. That is, various valves such as the priority valve main body 21 are integrally incorporated therein, and the hydraulic pump has a priority diversion function of diverting the supplied hydraulic fluid into a preferential flow and an excess flow. Priority is given to the hydraulic fluid required when the steering operation is performed. The port P serves as an inlet for the high-pressure hydraulic oil discharged from the tank 1, the tank ports T1 and T2 communicated with the tank 9, and the steering operation auxiliary circuit (not shown). And a surplus flow output port 2a for discharging surplus hydraulic fluid.

前記液圧ユニット３は、前記余剰流出力口２ａに接続したポンプ側ポート３ａと、アンロード弁４と、第１、第２、及び第３の流体制御弁５、６、７と、前記ポンプ側ポート３ａから供給される作動液を受ける高圧流路３１と、この高圧流路３１から分岐してなり第１〜第３の流体制御弁５〜７に作動液を供給するパラレル流路３２と、前記高圧流路３１を経て第３の流体制御弁７を通過した作動液、第１〜第３の流体制御弁５〜７から吐出された作動液、及び前記パラレル流路３２を通過した作動液を受ける戻り流路３３と、前記タンク側ポート３ｂとを有する。ここで、前記高圧流路３１と前記パラレル流路３２とは、パラレル流路分岐部３ｘにおいて分岐させてなる。また、前記高圧流路３１は前記ポンプ側ポート３ａから第３の流体制御弁７を通過し終わるまでの部位に設けている。そして、前記高圧流路３１が第３の流体制御弁７を通過し終わるまでの部位において、この高圧流路３１を前記戻り流路３３に断面形状を保ちつつ連通させている。なお、第１、第２、及び第３の流体制御弁５、６、７は、いずれも本発明の切替弁として機能する。   The hydraulic unit 3 includes a pump-side port 3a connected to the surplus flow output port 2a, an unload valve 4, first, second and third fluid control valves 5, 6, 7 and the pump A high-pressure channel 31 that receives the hydraulic fluid supplied from the side port 3a, and a parallel channel 32 that branches from the high-pressure channel 31 and supplies the hydraulic fluid to the first to third fluid control valves 5-7. , Hydraulic fluid that has passed through the third fluid control valve 7 via the high-pressure channel 31, hydraulic fluid discharged from the first to third fluid control valves 5 to 7, and actuation that has passed through the parallel channel 32 It has a return flow path 33 for receiving the liquid and the tank side port 3b. Here, the high-pressure channel 31 and the parallel channel 32 are branched at the parallel channel branching section 3x. The high-pressure channel 31 is provided at a site from the pump-side port 3a to the end of passing through the third fluid control valve 7. The high-pressure flow path 31 is communicated with the return flow path 33 while maintaining the cross-sectional shape in a portion until the high-pressure flow path 31 finishes passing through the third fluid control valve 7. Note that each of the first, second, and third fluid control valves 5, 6, and 7 functions as a switching valve of the present invention.

前記アンロード弁４は、図示しない着座センサに接続してなり、着座センサが運転席に操作者が着座していることを検知していない場合にのみ高圧流路３１を戻り流路３３に連通する。   The unload valve 4 is connected to a seating sensor (not shown). The unloading valve 4 communicates the high-pressure channel 31 with the return channel 33 only when the seating sensor does not detect that the operator is seated on the driver's seat. To do.

前記第１の流体制御弁５は、前記パラレル流路３２に接続される流入ポート５ａ、前記戻り流路３３に接続される吐出ポート５ｂ、及びリフトシリンダＬＳに接続される第１及び第２の出力ポート５ｃ、５ｄを有する。また、この第１の流体制御弁５は、前記高圧流路３１を連通させる中立位置と、前記流入ポート５ａと前記第１の出力ポート５ａとを連通させる上昇位置と、前記吐出ポート５ｂと前記第２の出力ポート５ｄとを連通させるとともに前記高圧流路３１を連通させる下降位置との３つの位置を選択的にとることができる。この第１の流体制御弁５は、第１の操作レバー５１に接続していて、この第１の操作レバー５１に対する操作を受けて前記３つの位置の間の切替を行うようにしている。また、第１の出力ポート５ｃとリフトシリンダＬＳとの間には、ロジック弁５２を設けている。このロジック弁５２の背圧室には、電磁弁５３を設けておりこの操作により前記リフトシリンダＬＳからの作動液の逆流によりリフトシリンダＬＳが下降することを抑止している。そして、リフトシリンダＬＳと第２の出力ポート５ｄとの間には、リフトシリンダＬＳから作動液が急激に戻り流路３に向けて流れてリフトシリンダＬＳが急下降することを防ぐべく、絞り弁５４を設けている。この絞り弁５４は、該絞り弁５４の前後の差圧が所定以上となった際に閉止する。前記リフトシリンダＬＳは、上述したように前記第１及び第２の出力ポート５ｃ、５ｄを介して前記第１の流体制御弁５に接続していて、作動液の供給を受けてこのリフトシリンダＬＳに接続したフォーク（図示略）を上昇させるとともに、作動液を吐出してこのリフトシリンダＬＳに接続したフォーク（図示略）を下降させる。   The first fluid control valve 5 includes an inflow port 5a connected to the parallel flow path 32, a discharge port 5b connected to the return flow path 33, and first and second connected to a lift cylinder LS. It has output ports 5c and 5d. The first fluid control valve 5 includes a neutral position for communicating the high-pressure channel 31, a raised position for communicating the inflow port 5a and the first output port 5a, the discharge port 5b, and the It is possible to selectively take three positions: a lowered position for communicating with the second output port 5d and for communicating with the high-pressure channel 31. The first fluid control valve 5 is connected to the first operation lever 51, and receives the operation on the first operation lever 51 to switch between the three positions. A logic valve 52 is provided between the first output port 5c and the lift cylinder LS. An electromagnetic valve 53 is provided in the back pressure chamber of the logic valve 52, and this operation prevents the lift cylinder LS from descending due to the backflow of the working fluid from the lift cylinder LS. A throttle valve is provided between the lift cylinder LS and the second output port 5d in order to prevent the working fluid from abruptly returning from the lift cylinder LS toward the flow path 3 and causing the lift cylinder LS to descend rapidly. 54 is provided. The throttle valve 54 is closed when the differential pressure before and after the throttle valve 54 exceeds a predetermined value. As described above, the lift cylinder LS is connected to the first fluid control valve 5 via the first and second output ports 5c and 5d, and receives the supply of hydraulic fluid to receive the lift cylinder LS. The fork (not shown) connected to is raised and the working fluid is discharged to lower the fork (not shown) connected to the lift cylinder LS.

前記第２の流体制御弁６は、前記パラレル流路３２に接続される流入ポート６ａ、前記戻り流路３３に接続される吐出ポート６ｂ、チルトシリンダＴＳのシリンダ室ＴＳ１側に接続される第１の出力ポート６ｃ、及びチルトシリンダＴＳのピストンＴＳ２側に接続される第２の出力ポート６ｄを有する。また、この第２の流体制御弁６は、前記高圧流路３１を連通させる中立位置と、前記流入ポート６ａと第１の出力ポート６ｃとを、また、前記吐出ポート６ｂと第２の出力ポート６ｄとを連通させる傾斜位置と、前記流入ポート６ａと第２の出力ポート６ｄとを、また、前記吐出ポート６ｂと第１の出力ポート６ｃとを連通させる起立位置との３つの位置を選択的にとることができる。この第２の流体制御弁６は、第２の操作レバー６１に接続していて、この第２の操作レバー６１に対する操作を受けて前記３つの位置の間の切替を行うようにしている。そして、この第２の流体制御弁６には、前記フォークを支持するマスト（図示略）を前傾させた姿勢で停止させた際に作動液の逆流によりこマストが前傾することを防ぐべく、チルトロックバルブ６Ｚが設けられている。前記チルトシリンダＴＳは、シリンダ室ＴＳ１及びピストンＴＳ２を備えていて、上述したように、前記シリンダ室ＴＳ１は前記第２の流体制御弁の第１出力ポート６ｃ、前記ピストンＴＳ２側は前記第２の流体制御弁の第２出力ポート６ｄに連通している。そして、前記シリンダ室ＴＳ１側に作動液の供給を受け、このチルタシリンダＴＳに接続しているとともに前記フォーク（図示略）を支持するマスト（図示略）を前傾させる。一方、前記ピストンＴＳ２側に作動液の供給を受けた際には、前記マスト（図示略）を前傾させた状態から起立状態に戻す。   The second fluid control valve 6 includes an inflow port 6a connected to the parallel flow path 32, a discharge port 6b connected to the return flow path 33, and a first cylinder connected to the cylinder chamber TS1 side of the tilt cylinder TS. Output port 6c and a second output port 6d connected to the piston TS2 side of the tilt cylinder TS. The second fluid control valve 6 includes a neutral position for communicating the high-pressure flow path 31, the inflow port 6a and the first output port 6c, and the discharge port 6b and the second output port. 3 positions of an inclined position for communicating 6d, an upright position for communicating the inflow port 6a and the second output port 6d, and a discharge position 6b and the first output port 6c are selectively used. Can be taken. The second fluid control valve 6 is connected to a second operation lever 61, and is switched between the three positions in response to an operation on the second operation lever 61. The second fluid control valve 6 includes a second fluid control valve 6 for preventing the mast from tilting forward due to the backflow of the working fluid when the mast (not shown) supporting the fork is stopped in a tilted posture. A tilt lock valve 6Z is provided. The tilt cylinder TS includes a cylinder chamber TS1 and a piston TS2. As described above, the cylinder chamber TS1 has the first output port 6c of the second fluid control valve, and the piston TS2 side has the second output port 6c. The fluid control valve communicates with the second output port 6d. Then, the hydraulic fluid is supplied to the cylinder chamber TS1, and a mast (not shown) that is connected to the tilter cylinder TS and supports the fork (not shown) is tilted forward. On the other hand, when the hydraulic fluid is supplied to the piston TS2 side, the mast (not shown) is returned from the tilted state to the standing state.

前記第３の流体制御弁７は、前記パラレル流路３２に接続される流入ポート７ａ、前記戻り流路３３に接続される吐出ポート７ｂ、回転機構Ｒの第１の流体導入口Ｒ１ａに接続される第１の出力ポート７ｃ、及び回転機構Ｒの第２の流体導入口Ｒ１ｂに接続される第２の出力ポート７ｄを有する。また、この第３の流体制御弁７は、前記高圧流路３１を連通させる中立位置と、前記流入ポート７ａと第１の出力ポート７ｃとを、また、前記吐出ポート７ｂと第２の出力ポート７ｄとを連通させる正回転位置と、前記流入ポート７ａと第２の出力ポート７ｄとを、また、前記吐出ポート７ｂと第１の出力ポート７ｃとを連通させる逆回転位置との３つの位置を選択的にとることができる。また、この第３の流体制御弁７は、第３の操作レバー７１に接続していて、この第３の操作レバー７１に対する操作を受けて前記３つの位置の間の切替を行うようにしている。前記回転機構Ｒは、第１及び第２の流体導入口Ｒ１ａ、Ｒ１ｂを有する油圧モータＲ１を利用して構成していて、この油圧モータＲ１に出力軸を介して接続した回転フォーク等の回転アタッチメント（図示略）を駆動する。具体的には、第１の流体導入口Ｒ１ａから作動液の供給を受けて回転アタッチメントを正方向に回転させ第２の流体導入口のＲ１ｂから作動液を吐出するとともに、第２の流体導入口Ｒ１ｂから作動液の供給を受けて回転アタッチメントを正方向に回転させ第１の流体導入口のＲ１ａから作動液を吐出する構成を有する。すなわち、この回転機構Ｒにより駆動される回転フォーク等の回転アタッチメントは、正逆両方向に回転可能である。   The third fluid control valve 7 is connected to an inflow port 7a connected to the parallel flow path 32, a discharge port 7b connected to the return flow path 33, and a first fluid introduction port R1a of the rotation mechanism R. A first output port 7c and a second output port 7d connected to the second fluid inlet R1b of the rotating mechanism R. The third fluid control valve 7 includes a neutral position for communicating the high-pressure flow path 31, the inflow port 7a and the first output port 7c, and the discharge port 7b and the second output port. The three positions of the forward rotation position for communicating 7d, the inflow port 7a and the second output port 7d, and the reverse rotation position for communicating the discharge port 7b and the first output port 7c. Can be taken selectively. The third fluid control valve 7 is connected to a third operating lever 71 and receives an operation on the third operating lever 71 to switch between the three positions. . The rotating mechanism R is configured using a hydraulic motor R1 having first and second fluid inlets R1a and R1b, and a rotating attachment such as a rotating fork connected to the hydraulic motor R1 via an output shaft. (Not shown) is driven. Specifically, the hydraulic fluid is supplied from the first fluid introduction port R1a, the rotary attachment is rotated in the forward direction, the hydraulic fluid is discharged from R2b of the second fluid introduction port, and the second fluid introduction port The hydraulic fluid is supplied from R1b, the rotary attachment is rotated in the forward direction, and the hydraulic fluid is discharged from R1a of the first fluid introduction port. That is, the rotary attachment such as a rotary fork driven by the rotary mechanism R can rotate in both forward and reverse directions.

そして、本実施形態では、最下流の切替弁すなわち前記第３の流体制御弁７の下流側に、前記高圧流路３１を経て中立位置にある前記第３の流体制御弁７を通過し戻り流路３３を流れる作動液の流量を検出するための流量検出手段たる絞り８１と、前記流量が所定値を上回る場合、すなわちこの絞り８１の前後の差圧が所定以上である場合にパラレル流路３２をタンク９に開放する制御弁８２とを有するパラレル流路開放部８をさらに具備する。   In this embodiment, the most downstream switching valve, that is, the downstream side of the third fluid control valve 7, passes through the third fluid control valve 7 in the neutral position via the high-pressure channel 31 and returns to the return flow. The parallel flow path 32 when the flow rate exceeds the predetermined value, that is, when the flow rate exceeds the predetermined value, that is, when the differential pressure before and after the throttle 81 is equal to or higher than the predetermined value. And a parallel flow path opening portion 8 having a control valve 82 for opening the tank 9 to the tank 9.

前記絞り８１は、戻り流路３３中に設けられ、前記高圧流路３１を経て中立位置にある前記第３の流体制御弁７を通過してこの絞り８１に達する作動液の流量をこの絞り８１の前後の差圧に変換する。   The throttle 81 is provided in the return flow path 33, and the flow rate of the working fluid that reaches the throttle 81 after passing through the third fluid control valve 7 in the neutral position via the high-pressure flow path 31 is reduced. Convert to differential pressure before and after.

前記制御弁８２は、本実施形態は、前記絞り８１の前後の差圧が所定以上である場合に開成するパイロット弁８２ａと、このパイロット弁８２ａの開閉に連動して開閉するロジック弁８２ｂとを組み合わせてなる。   In the present embodiment, the control valve 82 includes a pilot valve 82a that opens when the differential pressure across the throttle 81 is greater than or equal to a predetermined value, and a logic valve 82b that opens and closes in conjunction with the opening and closing of the pilot valve 82a. Combined.

前記パイロット弁８２ａは、パイロット通路８２ａ１を介して前記絞り８１の上流側及び下流側にそれぞれ接続している。そして、このパイロット通路８２ａ１により伝達される前記差圧が所定以上である場合に開成する。   The pilot valve 82a is connected to the upstream side and the downstream side of the throttle 81 through a pilot passage 82a1, respectively. And it opens when the said differential pressure transmitted by this pilot channel | path 82a1 is more than predetermined.

一方、前記ロジック弁８２ｂは、パラレル流路３２の開閉を行う弁本体８２ｂ１と、パラレル流路３２から液圧の供給を受けるとともに内部に弁本体８２ｂ１を閉止方向に付勢する付勢手段を有する背圧室８２ｂ２とを具備する。前記背圧室８２ｂ２は、前記パイロット弁８２ａに接続している。   On the other hand, the logic valve 82b has a valve body 82b1 that opens and closes the parallel flow path 32, and a biasing means that receives supply of fluid pressure from the parallel flow path 32 and biases the valve body 82b1 in the closing direction. And a back pressure chamber 82b2. The back pressure chamber 82b2 is connected to the pilot valve 82a.

ここで、運転席に操作者が着座している際において前記第１〜第３の流体制御弁５〜７が全て中立位置にある場合、及び前記第１の流体制御弁５が上昇位置にあり第２、第３の流体制御弁が中立位置にある場合の作動液の流れについて以下に述べる。   Here, when the operator is seated in the driver's seat, the first to third fluid control valves 5 to 7 are all in the neutral position, and the first fluid control valve 5 is in the raised position. The flow of hydraulic fluid when the second and third fluid control valves are in the neutral position will be described below.

前記余剰流吐出口２ａからポンプ側ポート３ａに達した作動液は、まず、高圧流路３１内を流れる。ここで、運転席に操作者が着座しているので、前記アンロード弁４は閉止状態にあり、従って作動液は高圧流路３１内を第１の流体制御弁５に向けて流れる。次いで、作動液の流れがパラレル流路分岐部３ｘにより分岐し、一部はパラレル流路３２内を流れる。一方、パラレル流路３２を経ずに高圧流路３１内を流れた作動液は、高圧流路３１内を貫通してパラレル流路開放部８の絞り８１に達する。ここで、この絞り８１の前後に、流量に比例して差圧が発生する。この絞り８１の前後に発生した差圧は、前記パイロット通路８２ａ１を経てパイロット弁８２ａに導入される。この差圧が所定以上であればパイロット弁８２ａが開成する。前記パイロット弁８２ａが開成すると、前記ロジック弁８２ｂの背圧室８２ｂ２が戻り流路３３を経てタンク９に連通するので、パラレル流路３２内の液圧が背圧室８２ｂ２内の付勢手段の付勢力に打ち勝ち、ロジック弁８２ｂの弁本体８２ｂが開成側に移動する。すなわち、パラレル流路３２が戻り流路３３を経てタンク９に開放される。従って、パラレル流路３２を経ずに高圧流路３１を貫通した作動液、及びパラレル流路３２内を流れた作動液は、ともにタンク９に向けて流れる。   The hydraulic fluid that has reached the pump-side port 3a from the excess flow outlet 2a first flows in the high-pressure channel 31. Here, since the operator is seated in the driver's seat, the unload valve 4 is in a closed state, and therefore the hydraulic fluid flows in the high-pressure channel 31 toward the first fluid control valve 5. Next, the flow of the hydraulic fluid is branched by the parallel flow path branching portion 3 x, and a part flows in the parallel flow path 32. On the other hand, the hydraulic fluid that has flowed through the high-pressure channel 31 without passing through the parallel channel 32 passes through the high-pressure channel 31 and reaches the throttle 81 of the parallel channel opening 8. Here, a differential pressure is generated before and after the throttle 81 in proportion to the flow rate. The differential pressure generated before and after the throttle 81 is introduced into the pilot valve 82a through the pilot passage 82a1. If the differential pressure is not less than a predetermined value, the pilot valve 82a is opened. When the pilot valve 82a is opened, the back pressure chamber 82b2 of the logic valve 82b communicates with the tank 9 via the return flow path 33, so that the hydraulic pressure in the parallel flow path 32 is applied to the urging means in the back pressure chamber 82b2. The urging force is overcome and the valve body 82b of the logic valve 82b moves to the open side. That is, the parallel flow path 32 is opened to the tank 9 via the return flow path 33. Therefore, the hydraulic fluid that has passed through the high-pressure channel 31 without passing through the parallel channel 32 and the hydraulic fluid that has flowed through the parallel channel 32 both flow toward the tank 9.

一方、前記第１の流体制御弁５が上昇位置にある場合は、高圧流路３１は第１の流体制御弁５の位置で閉塞される。また、第２、第３の流体制御弁６、７のうちいずれかが中立位置以外にある場合は、高圧流路３１は中立位置にない流体制御弁の位置で閉塞される。その際、前記絞り８１を通過する流量は減少するので、この絞り８１の前後の差圧が所定値を下回ると前記パイロット弁８２ａは閉止する。すると、ロジック弁８２ｂの背圧室８２ｂ２内の液圧はパラレル流路３２内の液圧と等しくなるまで上昇するので、ロジック弁８２ｂの弁本体８２ｂ１は背圧室８２ｂ２内の付勢手段により付勢されて閉止側に移動し、パラレル流路３２とタンク９に開放された状態は解消する。従って、例えば第２の流体制御弁６が中立位置以外の位置にあれば、優先弁機構２の余剰流出力口２ａから液圧ユニット３に供給される作動液のほぼ全量は、チルトシリンダＴＳに供給される。   On the other hand, when the first fluid control valve 5 is in the raised position, the high-pressure channel 31 is closed at the position of the first fluid control valve 5. When any one of the second and third fluid control valves 6 and 7 is in a position other than the neutral position, the high-pressure channel 31 is closed at the position of the fluid control valve that is not in the neutral position. At that time, since the flow rate passing through the throttle 81 decreases, the pilot valve 82a is closed when the differential pressure before and after the throttle 81 falls below a predetermined value. Then, the hydraulic pressure in the back pressure chamber 82b2 of the logic valve 82b increases until it becomes equal to the hydraulic pressure in the parallel flow path 32, so that the valve body 82b1 of the logic valve 82b is urged by the urging means in the back pressure chamber 82b2. The state of being moved to the closing side and released to the parallel flow path 32 and the tank 9 is eliminated. Therefore, for example, if the second fluid control valve 6 is in a position other than the neutral position, almost the entire amount of hydraulic fluid supplied from the surplus flow output port 2a of the priority valve mechanism 2 to the hydraulic pressure unit 3 is transferred to the tilt cylinder TS. Supplied.

以上に述べたように、本実施形態に係る液圧ユニット３の構成によれば、第１〜第３の流体制御弁５〜７がいずれも中立位置にあること等により、高圧流路３１の流量が大きくなった際には、パラレル流路３２がタンク９に開放されるので、高圧流路３１を経る経路だけでなくパラレル流路３２を経る経路も利用して作動液がタンク９に導かれる。従って、従来の構成において、高圧流路３１の断面積を、本実施形態における高圧流路３１の断面積とパラレル流路３２の断面積の和と同一にした場合と同様に、高圧流路の圧力損失を小さくすること、すなわち液圧ユニットの中立時圧力損失性能を向上させることができる。また、絞り８１により高圧流路３１を経て中立状態にある第３の流体制御弁７を通過する流量を検出し、この絞り８１の前後の差圧によりパイロット弁８２ａ及びロジック弁８２ｂを開閉するようにしているので、各流体制御弁にパイロット通路を接続する等の複雑な構成を採用することなく、簡単な構成及び少ない部品点数で前記効果を得ることができる。   As described above, according to the configuration of the hydraulic unit 3 according to the present embodiment, the first to third fluid control valves 5 to 7 are all in the neutral position, etc. When the flow rate increases, the parallel flow path 32 is opened to the tank 9, so that the hydraulic fluid is guided to the tank 9 using not only the path passing through the high pressure flow path 31 but also the path passing through the parallel flow path 32. It is burned. Therefore, in the conventional configuration, the cross-sectional area of the high-pressure flow path 31 is the same as the sum of the cross-sectional area of the high-pressure flow path 31 and the cross-sectional area of the parallel flow path 32 in this embodiment. The pressure loss can be reduced, that is, the neutral pressure loss performance of the hydraulic unit can be improved. Further, the flow rate passing through the third fluid control valve 7 in the neutral state is detected by the throttle 81 through the high-pressure channel 31, and the pilot valve 82 a and the logic valve 82 b are opened and closed by the differential pressure before and after the throttle 81. Therefore, the above-described effect can be obtained with a simple configuration and a small number of parts without adopting a complicated configuration such as connecting a pilot passage to each fluid control valve.

なお、本発明は以上に述べた実施形態に限られない。   The present invention is not limited to the embodiment described above.

例えば、切替弁の個数は３個に限らず、切替弁を１個のみ設けたものや、２個の切替弁のみをスタックさせたものや４個以上の切替弁をスタックさせたものであってもよい。また、上述した実施形態において、第３の流体制御弁７には、回転機構Ｒでなく、他の機構、例えばマストを左右に傾斜させるためのシリンダ等を接続してもよい。さらに、優先弁機構と複数の切替弁とを積層させてなるマルチスタック型液圧ユニットに限らず、複数の切替弁を全て一体に形成したものでもよく、また、優先弁機構と１又は複数の切替弁とを一体に形成したものであってもよい。   For example, the number of switching valves is not limited to three, but only one switching valve is provided, only two switching valves are stacked, or four or more switching valves are stacked. Also good. In the above-described embodiment, the third fluid control valve 7 may be connected to another mechanism, for example, a cylinder for tilting the mast left and right, instead of the rotation mechanism R. Furthermore, it is not limited to a multi-stack type hydraulic unit formed by laminating a priority valve mechanism and a plurality of switching valves, but may be one in which a plurality of switching valves are integrally formed. It may be formed integrally with the switching valve.

また、制御弁の構成は、上述した実施形態に係るものに限らず、例えば、前記パイロット弁を単独で用いるもの等が考えられる。   Further, the configuration of the control valve is not limited to that according to the above-described embodiment, and for example, one that uses the pilot valve alone can be considered.

さらに、流量検出手段としては、上述した実施形態に係る絞りに限らず、例えば、高圧流路を経て最下流の切替弁を通過する流量を直接検出する流量センサを用いてもよい。この場合、前記制御弁を、流量センサが検出した前記流量が所定以上であることを示す信号を受けて開成し、流量センサが検出した前記流量が所定未満であることを示す信号を受けて閉止する電磁弁を利用して構成するとよい。   Furthermore, the flow rate detection means is not limited to the throttle according to the above-described embodiment, and for example, a flow rate sensor that directly detects the flow rate that passes through the switching valve on the most downstream side through the high-pressure channel may be used. In this case, the control valve is opened in response to a signal indicating that the flow rate detected by the flow sensor is greater than or equal to a predetermined value, and is closed in response to a signal indicating that the flow rate detected by the flow sensor is less than a predetermined value. It is good to comprise using the solenoid valve to do.

その他、本発明の趣旨を損ねない範囲で種々に変更してよい。   In addition, various changes may be made without departing from the spirit of the present invention.

本発明の一実施形態に係る液圧ユニットを含む液圧回路を示す図。The figure which shows the hydraulic circuit containing the hydraulic unit which concerns on one Embodiment of this invention.

符号の説明Explanation of symbols

３…液圧ユニット
３１…高圧流路
３２…パラレル流路
５〜７…第１〜第３の流体制御弁（切替弁）
８１…絞り（流量検出手段）
８２…制御弁 DESCRIPTION OF SYMBOLS 3 ... Hydraulic pressure unit 31 ... High pressure flow path 32 ... Parallel flow path 5-7 ... 1st-3rd fluid control valve (switching valve)
81 ... Restriction (flow rate detection means)
82 ... Control valve

Claims (1)

複数の切替弁と、中立状態にある前記複数の切替弁を貫通し液圧供給源からの作動液をタンクに導く高圧流路と、この高圧流路から分岐させてなり前記各切替弁に作動液を導くためのパラレル流路とを具備し、前記複数の切替弁が前記高圧流路及び前記パラレル流路を共通に使用する液圧ユニットの構造であって、高圧流路を経て最下流の切替弁を通過する流量を検出するための流量検出手段と、この流量検出手段が検出した前記流量が所定値を上回る場合にパラレル流路をタンクに開放する制御弁とをさらに具備することを特徴とする液圧ユニットの構造。 A plurality of switching valves, a high-pressure channel that passes through the plurality of switching valves in a neutral state and guides hydraulic fluid from a hydraulic pressure supply source to the tank, and is branched from the high-pressure channel and operates on each switching valve. A parallel flow path for guiding the liquid, wherein the plurality of switching valves have a structure of a hydraulic unit that commonly uses the high pressure flow path and the parallel flow path, and the most downstream through the high pressure flow path. It further comprises flow rate detection means for detecting a flow rate passing through the switching valve, and a control valve that opens the parallel flow path to the tank when the flow rate detected by the flow rate detection means exceeds a predetermined value. The structure of the hydraulic unit.
JP2008306658A 2008-12-01 2008-12-01 Structure of hydraulic unit Pending JP2010127457A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPWO2017006417A1 (en) * 2015-07-06 2018-03-01 株式会社島津製作所 Fluid control device

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPWO2017006417A1 (en) * 2015-07-06 2018-03-01 株式会社島津製作所 Fluid control device

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