JP2005172080A - Hydraulic driving apparatus - Google Patents

Hydraulic driving apparatus Download PDF

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JP2005172080A
JP2005172080A JP2003411229A JP2003411229A JP2005172080A JP 2005172080 A JP2005172080 A JP 2005172080A JP 2003411229 A JP2003411229 A JP 2003411229A JP 2003411229 A JP2003411229 A JP 2003411229A JP 2005172080 A JP2005172080 A JP 2005172080A
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valve
counter balance
hydraulic
neutral position
hydraulic motor
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JP4263589B2 (en
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Takaya Yokota
貴也 横田
Daisuke Yoshioka
大介 吉岡
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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 a hydraulic driving apparatus which can prevent the occurrence of cavitation, noise, vibration, etc. between a counterbalance valve and a hydraulic motor after the counterbalance valve has been changed from the opened state to the closed state, without using a shock absorbing circuit having a relief valve, which has a complicated structure and is economically disadvantageous. <P>SOLUTION: When a directional control valve 25 has been shifted to a neutral position, a spool 2 of a bypass valve 1 is returned to the neutral position later than the main spool 102 of the counterbalance valve 26. When the main spool 102 has returned to the neutral position, the supply of pressurized oil to the hydraulic motor 20 is stopped. At this time, the hydraulic motor 20 continues to rotate for a while. As a result, the pressure in a B' line becomes high. On the contrary, the pressure in an A' line becomes negative. In this case, the negative pressure oil in the A' line opens a check valve 31 via oil supply passages 14, 12, and the oil in the B line is introduced to a drain via a clearance 35, oil supply passages 13, 15, and the counterbalance valve 26. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

本発明は、本発明は建設機械・農業機械等の油圧走行モータに使用される、ポンプ、ポンプの圧油の方向切換弁、方向切換弁の２個のポートに連通されたカウンターバランス弁、カウンターバランス弁の下流に油圧走行モータである油圧モータとを有する油圧駆動装置に使用される油圧駆動装置に関する。   The present invention relates to a pump, a hydraulic pressure direction switching valve of a pump, a counter balance valve communicated with two ports of the direction switching valve, and a counter used in a hydraulic traveling motor of a construction machine or an agricultural machine. The present invention relates to a hydraulic drive device used in a hydraulic drive device having a hydraulic motor that is a hydraulic traveling motor downstream of a balance valve.

従来の建設機械・農業機械等の油圧走行モータに使用される、従来のポンプ、ポンプの圧油の方向切換弁、方向切換弁の２個のポートに連通されたカウンターバランス弁を有する油圧駆動装置においては、カウンターバランス弁の主スプールは方向切換弁の２個のポートにそれぞれ連通された２個の絞りを介したパイロット油路の自己圧により、方向切換弁が中立にされたとき、カウンターバランス弁の主スプールは中立位置に戻るようにされているが、負荷（油圧モータとそれが駆動する駆動部分）の慣性力により、カウンターバランス弁と油圧モータとの間にキャビテーションが発生し、騒音・振動等が発生し、公害・装置の寿命低下を招いた。かかるキャビテーション、騒音・振動等の発生を防止するため、特許文献１では、カウンターバランス弁が開状態の時に、カウンターバランス弁の排出側と油圧モータやカウンターバランス弁の吸入側とを連通する給油路とカウンターバランス弁と連通した緩衝回路とを設け、油圧モータの停止操作が行われてカウンターバランス弁が閉状態に切り換わるまでの間は、カウンターバランス弁の排出側から油圧モータやカウンターバランス弁の吸入側へ連通する給油路により油を流入させてキャビテーション等の発生を防止し、さらにカウンターバランス弁が閉状態に切り換わってからは、カウンターバランス弁と連通した緩衝回路のリリーフ弁が作動して油圧モータの排出側から吸入側に油が循環し、キャビテーション等の発生を防止するものである。キャビテーション、騒音・振動等の発生を防止する従来の別の技術は特許文献２に開示され、この場合、油圧モータとカウンターバランス弁との間に、油圧モータの排出側と吸入側とを連通するようにバイパス弁を設け、油圧モータの停止操作が行われてカウンターバランス弁が閉状態になった後でもバイパス弁が開状態となるようにすることで、油圧モータの排出側から吸入側へ油を流入させ、キャビテーション等の発生を防止するものである。
特開2003-184801 号公報 特開平11-22702号公報 A hydraulic drive device having a counter balance valve connected to two ports of a conventional pump, a pump pressure oil direction switching valve, and a direction switching valve, which is used for a hydraulic traveling motor of a conventional construction machine or agricultural machine In the case of the counterbalance valve, the main spool of the counterbalance valve is counterbalanced when the directional control valve is neutralized by the self-pressure of the pilot oil passage through two throttles respectively connected to the two ports of the directional control valve. The main spool of the valve is returned to the neutral position, but cavitation occurs between the counterbalance valve and the hydraulic motor due to the inertia of the load (hydraulic motor and the drive part that it drives). Vibration, etc., caused pollution and reduced equipment life. In order to prevent the occurrence of such cavitation, noise, vibration, etc., in Patent Document 1, when the counterbalance valve is in an open state, an oil supply passage that communicates the discharge side of the counterbalance valve with the suction side of the hydraulic motor or the counterbalance valve And a buffer circuit communicating with the counter balance valve, and until the counter balance valve is switched to the closed state after the hydraulic motor is stopped, the hydraulic motor and the counter balance valve are connected from the discharge side of the counter balance valve. The oil is introduced through the oil supply passage that communicates with the suction side to prevent cavitation, etc., and after the counter balance valve is switched to the closed state, the relief valve of the buffer circuit that communicates with the counter balance valve is activated. Oil circulates from the discharge side of the hydraulic motor to the suction side to prevent the occurrence of cavitation, etc. It is. Another conventional technique for preventing the occurrence of cavitation, noise, vibration, etc. is disclosed in Patent Document 2. In this case, the discharge side and the suction side of the hydraulic motor are communicated between the hydraulic motor and the counterbalance valve. By providing a bypass valve in this way, the bypass valve can be opened even after the hydraulic motor is stopped and the counterbalance valve is closed. Inflow and prevent the occurrence of cavitation and the like.
JP 2003-184801 A Japanese Patent Laid-Open No. 11-22702

しかしながら特許文献１では、給油路の作用のみによるキャビテーション等の発生の防止効果が得られるのは、油圧モータの停止操作が行われてからカウンターバランス弁が閉状態に切り換わるまでの間で、カウンターバランス弁が閉状態に切り換わった後で油圧モータが慣性回動した場合、給油路の作用ではキャビテーションの発生を防止することはできないので、カウンターバランス弁が閉状態に切り換わった後もキャビテーションの発生を防止する場合は、リリーフ弁を有する緩衝回路を併設しなければならず、給油路のみの構造に比べ、油圧モータ駆動回路の構造が複雑なものとなってしまい、経済的にも不利になる。又、特許文献２では、建設機械・農業機械等の降坂運転時、機体の自重で油圧走行モータに回転させようとする外力が働き、油圧走行モータがポンプ作用し、排出側の圧力がカウンターバランス弁の絞りの影響で吸入側の圧力より高圧になる場合がある。その場合、油圧走行モータの排出側から吸入側へ油がバイパス弁を通って流入し、バイパス弁の閉止が遅れ、油圧走行モータの停止が遅れるおそれがあった。   However, in Patent Document 1, the effect of preventing the occurrence of cavitation or the like by only the operation of the oil supply passage is obtained between the time when the hydraulic motor is stopped and the time when the counter balance valve is switched to the closed state. If the hydraulic motor rotates inertial after the balance valve switches to the closed state, the oil supply passage cannot prevent cavitation from occurring, so even after the counterbalance valve switches to the closed state, In order to prevent the occurrence, a buffer circuit having a relief valve must be provided, and the structure of the hydraulic motor drive circuit becomes more complicated than the structure of only the oil supply passage, which is disadvantageous economically. Become. Further, in Patent Document 2, when a downhill operation is performed on a construction machine, an agricultural machine, etc., an external force is applied to rotate the hydraulic traveling motor by its own weight, the hydraulic traveling motor acts as a pump, and the pressure on the discharge side is countered. The pressure on the suction side may become higher due to the balance valve throttle. In that case, oil flows from the discharge side to the suction side of the hydraulic traveling motor through the bypass valve, and the closing of the bypass valve is delayed, and the stopping of the hydraulic traveling motor may be delayed.

本発明の課題は、構造が複雑で経済的にも不利なリリーフ弁を有する緩衝回路を使用することなく、カウンターバランス弁が開状態から閉状態に切り換わった後も、負荷（油圧モータとそれが駆動する駆動部分）の慣性力により、カウンターバランス弁と油圧モータとの間のキャビテーション、騒音・振動等の発生を防止する、油圧駆動装置を提供することにある。
本発明の別の課題は、建設機械・農業機械等の降坂運転時、機体の自重で油圧走行モータに回転させようとする外力が働くときも、排出側の圧力がカウンターバランス弁の絞りの影響で吸入側の圧力より高圧になっても、油圧走行モータの停止が遅れるおそれがない油圧駆動装置を提供することにある。 The object of the present invention is to provide a load (hydraulic motor and its) after the counterbalance valve is switched from the open state to the closed state without using a buffer circuit having a relief valve that is complicated in structure and economically disadvantageous. It is an object of the present invention to provide a hydraulic drive device that prevents the occurrence of cavitation, noise, vibration, and the like between a counter balance valve and a hydraulic motor due to the inertial force of a drive portion).
Another problem of the present invention is that the pressure on the discharge side of the counterbalance valve is reduced even when an external force is applied to the hydraulic traveling motor by its own weight during downhill operation of construction machinery, agricultural machinery, etc. It is an object of the present invention to provide a hydraulic drive device that does not cause a delay in stopping of the hydraulic traveling motor even if the pressure on the suction side becomes higher than the suction side.

このため本発明は、ポンプ、ポンプの圧油の方向切換弁、方向切換弁の２個のポートに連通されたカウンターバランス弁、カウンターバランス弁の下流に配置した油圧モータとを有する油圧駆動装置において、前記カウンターバランス弁の排出側と前記油圧モータ及びカウンターバランス弁の吸入側とを連通するようにバイパス弁を設け、前記バイパス弁は一対のスプリングにより中立位置に付勢された１本のスプールに内蔵された２個の対向するチェック弁を有し、２個のチェック弁は前記カウンターバランス弁の排出側と吸入側とそれぞれ連通する２個の連通路によって、いずれかが開かれたとき、前記カウンターバランス弁の排出側と前記油圧モータ及びカウンターバランス弁の吸入側とを連通可能にされており、前記カウンターバランス弁の一対の主スプリングにより中立位置に付勢された主スプールは前記方向切換弁の２個のポートにそれぞれ連通された２個の絞りを介したパイロット油路の自己圧により中立位置に戻るようにされており、前記２個のチョーク付きドレン油路は前記２個の絞りを介したパイロット油路と連通されており、前記絞りは前記チョークより大きい開口面積を有し、かつ前記カウンターバランス弁の主スプリングは前記バイパス弁のスプリングより強い付勢力を有し、前記方向切換弁が中立にされたとき、前記バイパス弁のスプールが前記カウンターバランス弁の主スプールより遅く中立位置に戻るようにされたことを特徴とする油圧駆動装置を提供することにより上記した本発明の課題を解決した。   For this reason, the present invention relates to a hydraulic drive apparatus having a pump, a direction switching valve for pressure oil of the pump, a counterbalance valve communicated with two ports of the direction switching valve, and a hydraulic motor disposed downstream of the counterbalance valve. A bypass valve is provided so as to communicate the discharge side of the counter balance valve with the suction side of the hydraulic motor and the counter balance valve, and the bypass valve is provided on a single spool biased to a neutral position by a pair of springs. When two of the check valves are opened by two communication passages that respectively communicate with the discharge side and the suction side of the counter balance valve, The discharge side of the counter balance valve can communicate with the suction side of the hydraulic motor and the counter balance valve. The main spool urged to the neutral position by the pair of main springs of the valve is returned to the neutral position by the self-pressure of the pilot oil passage through the two throttles respectively connected to the two ports of the direction switching valve. The two choke drain oil passages communicate with a pilot oil passage through the two throttles, the throttle has an opening area larger than the choke, and the counterbalance The main spring of the valve has a stronger biasing force than the spring of the bypass valve, and when the direction switching valve is neutral, the spool of the bypass valve returns to the neutral position later than the main spool of the counter balance valve. The above-described problems of the present invention have been solved by providing a hydraulic drive device characterized by the above.

以上説明したように、本発明の油圧駆動装置は、建設機械・農業機械等の油圧走行モータに使用される、従来のポンプ、ポンプの圧油の方向切換弁、方向切換弁の２個のポートに連通されたカウンターバランス弁を有する油圧駆動装置において、バイパス弁を設け、カウンターバランス弁の絞りはバイパス弁１のチョークより大きい開口面積を有し、かつカウンターバランス弁の主スプリングはバイパス弁のスプリングより強い付勢力を有し、方向切換弁が中立にされたとき、バイパス弁のスプールがカウンターバランス弁の主スプールより遅く中立位置に戻るようにされた油圧駆動装置としたので、油圧モータへの圧油供給が遮断され、負荷の慣性力により、油圧モータが回転を続けようとしても、油圧モータ出口ラインに発生した高圧圧油は、バイパス弁のスプールが中立位置に戻るまで、カウンターバランス弁の排出側を通り油圧モータ及びカウンターバランス弁の吸入側に油が流れ、キャビテーションの発生を防止し、騒音・振動等の発生を防止し、公害・装置の寿命低下を招くことのない油圧駆動装置となった。
また、カウンターバランス弁の排出側と油圧モータやカウンターバランス弁の吸入側とを連通するようにバイパス弁を設けることにより、建設機械・農業機械等の降坂運転時、機体の自重で油圧走行モータに回転させようとする外力が働き、油圧走行モータの排出側の圧力が吸入側の圧力より高圧になる場合でも、油圧走行モータの停止が遅れるおそれがない油圧駆動装置を提供するものとなった。
好ましくは、前記絞りはカウンターバランス弁に内蔵され、前記チョークは前記バイパス弁に内蔵されたので、極めてコンパクトな油圧駆動装置を提供するものとなった。 As described above, the hydraulic drive device of the present invention has two ports of a conventional pump, a pump pressure oil direction switching valve, and a direction switching valve, which are used in hydraulic traveling motors such as construction machinery and agricultural machinery. In the hydraulic drive apparatus having a counterbalance valve communicated with the bypass valve, a bypass valve is provided, the throttle of the counterbalance valve has an opening area larger than the choke of the bypass valve 1, and the main spring of the counterbalance valve is a spring of the bypass valve Since the hydraulic drive unit has a stronger urging force and the bypass valve spool returns to the neutral position later than the main spool of the counter balance valve when the directional control valve is neutral, the hydraulic motor is connected to the hydraulic motor. Even if the hydraulic oil supply is cut off and the hydraulic motor continues to rotate due to the inertia of the load, the high pressure generated in the hydraulic motor outlet line Until the bypass valve spool returns to the neutral position, oil flows through the discharge side of the counterbalance valve to the suction side of the hydraulic motor and counterbalance valve, preventing cavitation and preventing noise and vibration. Thus, the hydraulic drive device does not cause pollution or a reduction in device life.
In addition, by providing a bypass valve so that the discharge side of the counter balance valve communicates with the suction side of the hydraulic motor or counter balance valve, the hydraulic travel motor is driven by its own weight during downhill operation of construction machinery, agricultural machinery, etc. The hydraulic drive device is provided that does not have the possibility of delaying the stoppage of the hydraulic travel motor even when the external force that causes the hydraulic travel motor to act on and the pressure on the discharge side of the hydraulic travel motor becomes higher than the pressure on the suction side. .
Preferably, the throttle is built in the counter balance valve, and the choke is built in the bypass valve, thereby providing a very compact hydraulic drive.

本発明を実施するための最良の形態の油圧駆動装置について、以下添付した図１及び図２に基づきこの発明を詳細に説明する。図１は本発明を実施するための最良の形態の油圧駆動装置の油圧回路図、図２は図１のバイパス弁のスプール２が図でみて右端まで移動した状態を示す説明図、をそれぞれ示す。図１において、原動機２２で駆動されるポンプ２１の圧油は流量制御弁２３を通り方向切換弁２５に連通され、方向切換弁２５の２個のポートＡ、Ｂに連通されたカウンターバランス弁２６と、その下流の油圧モータ２０に接続されている。方向切換弁２５とカウンターバランス弁２６との間に、カウンターバランス弁２６の排出側ｂと油圧モータ２０及びカウンターバランス弁２６の吸入側ａとを連通するようにバイパス弁１が接続され、バイパス弁１は一対のスプリング６により中立位置に付勢された１本のスプール２に内蔵された２個の対向するチェック弁３１、３２を有し、２個のチェック弁３１、３２はそれぞれ給油路１２、１３と隙間３５との間に配置されている。２個のチェック弁３１、３２は２個の連通路１２及び１４、１３及び１５によってカウンターバランス弁２６の吸入側ａと排出側ｂとに連通し、いずれかが開かれたとき、カウンターバランス弁２６の排出側ｂと油圧モータ２０及びカウンターバランス弁２６の吸入側ａとを連通可能にされており、カウンターバランス弁２６の一対の主スプリング１０６により中立位置に付勢された主スプール１０２は方向切換弁２５の２個のポートＡ、Ｂにそれぞれ連通された２個の絞り１０８、１０８を介したパイロット油路１０９、１０９の自己圧により中立位置に戻るようにされている。そして２個のチョーク付きドレン油路１０、１１は２個の絞り１０８、１０８を介したパイロット油路１０９、１０９と連通されており、カウンターバランス弁２６の絞り１０８はチョーク８より大きい開口面積を有し、かつカウンターバランス弁２６の主スプリング１０６はバイパス弁１のスプリング６より強い付勢力を有し、方向切換弁２５が中立にされたとき、バイパス弁１のスプール２がカウンターバランス弁２６の主スプール１０２より遅く中立位置に戻るようにされている。   BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail with reference to FIGS. 1 and 2 attached below with regard to the best mode hydraulic drive device for carrying out the present invention. FIG. 1 is a hydraulic circuit diagram of a hydraulic drive device according to the best mode for carrying out the present invention, and FIG. 2 is an explanatory view showing a state where the spool 2 of the bypass valve in FIG. . In FIG. 1, the pressure oil of the pump 21 driven by the prime mover 22 passes through the flow control valve 23 and communicates with the direction switching valve 25, and the counter balance valve 26 communicates with the two ports A and B of the direction switching valve 25. To the downstream hydraulic motor 20. The bypass valve 1 is connected between the direction switching valve 25 and the counterbalance valve 26 so that the discharge side b of the counterbalance valve 26 and the suction side a of the hydraulic motor 20 and the counterbalance valve 26 communicate with each other. 1 includes two opposing check valves 31 and 32 built in one spool 2 urged to a neutral position by a pair of springs 6, and the two check valves 31 and 32 are respectively oil supply passages 12. , 13 and the gap 35. The two check valves 31 and 32 communicate with the suction side a and the discharge side b of the counter balance valve 26 through the two communication passages 12 and 14, 13 and 15, and when one of them is opened, the counter balance valve 26 is connected to the suction side a of the hydraulic motor 20 and the counter balance valve 26, and the main spool 102 biased to the neutral position by the pair of main springs 106 of the counter balance valve 26 is directional. The self-pressure of the pilot oil passages 109 and 109 through the two throttles 108 and 108 communicated with the two ports A and B of the switching valve 25 is set back to the neutral position. The two drain oil passages 10 and 11 with chokes communicate with the pilot oil passages 109 and 109 via the two throttles 108 and 108, and the throttle 108 of the counter balance valve 26 has an opening area larger than that of the choke 8. And the main spring 106 of the counterbalance valve 26 has a stronger biasing force than the spring 6 of the bypass valve 1, and when the direction switching valve 25 is neutral, the spool 2 of the bypass valve 1 is connected to the counterbalance valve 26. It returns to the neutral position later than the main spool 102.

かかる構成により、本発明の油圧駆動装置は、Ａポートに圧油が供給されたとき、カウンターバランス弁２６の主スプール１０２と同様に、バイパス弁１のスプール２は図２に示すように右端まで移動する。次に方向切換弁２５が中立にされＡポートの圧油供給が遮断されると、カウンターバランス弁２６の主スプール１０２とバイパス弁１のスプール２はそれぞれ主スプリング１０６、スプリング６により中立位置に戻る。しかしながら、絞り１０８はチョーク８より大きい開口面積を有し、かつカウンターバランス弁２６の主スプリング１０６はバイパス弁１のスプリング６より強い付勢力を有するので、方向切換弁２５が中立にされたとき、バイパス弁１のスプール２がカウンターバランス弁２６の主スプール１０２より遅く中立位置に戻る。カウンターバランス弁２６の主スプール１０２が中立位置に戻ると、油圧モータ２０への圧油供給が遮断されるが、負荷（油圧モータ２０とそれが駆動する駆動部分）の慣性力により、油圧モータ２０は回転を続けようとし、方向切換弁２５のポートＢ’ラインが高圧になり、逆にＡ’ラインが負圧（キャビテーション発生）となる。この時、バイパス弁１が中立位置に戻るまで、バイパス弁１とカウンターバランス弁２６との関係は図２の状態の位置のままであるので、負圧となったＡ’ラインは、カウンターバランス弁２６の内蔵チェック弁を開き、カウンターバランス弁２６の吸入側ａを通り、給油路１４、１２を介してバイパス弁１のチェック弁３１を開き、隙間３５、給油路１３、１５、カウンターバランス弁２６の排出側ｂを介してＢラインの油をドレンに流入させる。これにより、キャビテーション、騒音・振動等の発生を防止し、公害・装置の寿命低下を招くことのない油圧駆動装置となった。また本発明の油圧駆動装置では、絞り１０８はカウンターバランス弁２６に内蔵され、バイパス弁１のチョーク８はバイパス弁１に内蔵されたので、極めてコンパクトな油圧駆動装置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〕 With this configuration, when hydraulic oil is supplied to the A port, the hydraulic drive device of the present invention allows the spool 2 of the bypass valve 1 to reach the right end as shown in FIG. Moving. Next, when the direction switching valve 25 is neutralized and the pressure oil supply to the A port is shut off, the main spool 102 of the counter balance valve 26 and the spool 2 of the bypass valve 1 are returned to the neutral position by the main spring 106 and the spring 6, respectively. . However, since the throttle 108 has an opening area larger than that of the choke 8 and the main spring 106 of the counterbalance valve 26 has a stronger biasing force than the spring 6 of the bypass valve 1, when the direction switching valve 25 is neutralized, The spool 2 of the bypass valve 1 returns to the neutral position later than the main spool 102 of the counter balance valve 26. When the main spool 102 of the counter balance valve 26 returns to the neutral position, the supply of pressure oil to the hydraulic motor 20 is interrupted, but due to the inertial force of the load (the hydraulic motor 20 and the drive portion that drives it), the hydraulic motor 20 Tries to continue rotating, and the port B ′ line of the direction switching valve 25 becomes high pressure, and conversely, the A ′ line becomes negative pressure (cavitation generation). At this time, until the bypass valve 1 returns to the neutral position, the relationship between the bypass valve 1 and the counterbalance valve 26 remains at the position shown in FIG. 26, the check valve 31 of the bypass valve 1 is opened through the oil supply passages 14 and 12, the clearance 35, the oil supply passages 13 and 15, and the counter balance valve 26 are opened. The oil of the B line is caused to flow into the drain through the discharge side b of As a result, the hydraulic drive apparatus is prevented from generating cavitation, noise, vibration, etc., and causing no pollution or a reduction in the service life of the apparatus. Further, in the hydraulic drive device of the present invention, the throttle 108 is built in the counter balance valve 26, and the choke 8 of the bypass valve 1 is built in the bypass valve 1, so that an extremely compact hydraulic drive device is provided.
[Effect of Best Embodiment of the Present Invention]

以上説明したように、本発明の油圧駆動装置は、方向切換弁が中立にされたとき、バイパス弁のスプールがカウンターバランス弁の主スプールより遅く中立位置に戻るようにされた油圧駆動装置としたので、カウンターバランス弁が閉状態に切り換わった後も、バイパス弁が閉状態に切り換わるまでの間、カウンターバランス弁の排出側から油圧モータやカウンターバランス弁の吸入側へ油を流入させることができる。これにより、構造が複雑で経済的にも不利なリリーフ弁を有する緩衝回路がなくても、カウンターバランス弁が閉状態に切り換わった後も給油路による作用でキャビテーションが防止できる油圧モータ駆動装置を提供するものとなった。
また、カウンターバランス弁の排出側と油圧モータやカウンターバランス弁の吸入側とを連通するようにバイパス弁を設けることにより、建設機械・農業機械等の降坂運転時、機体の自重で油圧走行モータに回転させようとする外力が働き、油圧走行モータの排出側の圧力が吸入側の圧力より高圧になる場合でも、油圧走行モータの停止が遅れるおそれがない油圧駆動装置を提供するものとなった。 As described above, the hydraulic drive device of the present invention is a hydraulic drive device in which when the directional control valve is neutral, the spool of the bypass valve returns to the neutral position later than the main spool of the counter balance valve. Therefore, even after the counter balance valve is switched to the closed state, the oil can be allowed to flow from the discharge side of the counter balance valve to the hydraulic motor or the intake side of the counter balance valve until the bypass valve is switched to the closed state. it can. As a result, a hydraulic motor drive device that can prevent cavitation due to the action of the oil supply passage even after the counter balance valve is switched to the closed state, even if there is no buffer circuit having a relief valve that is complicated and economically disadvantageous. It became something to offer.
In addition, by providing a bypass valve so that the discharge side of the counter balance valve communicates with the suction side of the hydraulic motor or counter balance valve, the hydraulic travel motor is driven by its own weight during downhill operation of construction machinery, agricultural machinery, etc. The hydraulic drive device is provided that does not have the possibility of delaying the stoppage of the hydraulic travel motor even when the external force that causes the hydraulic travel motor to act on and the pressure on the discharge side of the hydraulic travel motor becomes higher than the pressure on the suction side. .

本発明の最良の実施形態の油圧駆動装置の油圧回路図を示す。1 shows a hydraulic circuit diagram of a hydraulic drive device according to a best embodiment of the present invention. 図１のバイパス弁のスプールが図でみて右端まで移動した状態を示す説明図を示す。FIG. 2 is an explanatory diagram showing a state where the spool of the bypass valve in FIG. 1 has moved to the right end in the drawing.

符号の説明Explanation of symbols

１．．バイパス弁
２．．バイパス弁のスプール
６．．バイパス弁のスプリング
１２、１４．．Ａポート側の給油路
１３、１５．．Ｂポート側の給油路
２０．．油圧モータ
２５．．方向切換弁
２６．．カウンターバランス弁
１０２．．カウンターバランス弁の主スプール
１０６．．カウンターバランス弁の主スプリング
ａ．．カウンターバランス弁の排出側
ｂ．．油圧モータ及びカウンターバランス弁の吸入側 1. . 1. Bypass valve . 5. Bypass valve spool . Bypass valve springs 12,14. . A port side oil supply passage 13, 15. . B port side oil supply passage 20. . Hydraulic motor 25. . Direction switching valve 26. . Counter balance valve 102. . Main spool 106 of counter balance valve . Main spring of counter balance valve a. . Discharge side of counter balance valve b. . Suction side of hydraulic motor and counter balance valve

Claims (2)

ポンプ、ポンプの圧油の方向切換弁、方向切換弁の２個のポートに連通されたカウンターバランス弁、カウンターバランス弁の下流に配置した油圧モータとを有する油圧駆動装置において、前記カウンターバランス弁の排出側と前記油圧モータ及びカウンターバランス弁の吸入側とを連通するようにバイパス弁を設け、前記バイパス弁は一対のスプリングにより中立位置に付勢された１本のスプールに内蔵された２個の対向するチェック弁を有し、２個のチェック弁は前記カウンターバランス弁の排出側と吸入側とそれぞれ連通する２個の連通路によって、いずれかが開かれたとき、前記カウンターバランス弁の排出側と前記油圧モータ及びカウンターバランス弁の吸入側とを連通可能にされており、前記カウンターバランス弁の一対の主スプリングにより中立位置に付勢された主スプールは前記方向切換弁の２個のポートにそれぞれ連通された２個の絞りを介したパイロット油路の自己圧により中立位置に戻るようにされており、前記２個のチョーク付きドレン油路は前記２個の絞りを介したパイロット油路と連通されており、前記絞りは前記チョークより大きい開口面積を有し、かつ前記カウンターバランス弁の主スプリングは前記バイパス弁のスプリングより強い付勢力を有し、前記方向切換弁が中立にされたとき、前記バイパス弁のスプールが前記カウンターバランス弁の主スプールより遅く中立位置に戻るようにされたことを特徴とする油圧駆動装置。 A hydraulic drive device comprising: a pump, a direction switching valve for pressure oil of the pump, a counter balance valve communicated with two ports of the direction switching valve, and a hydraulic motor disposed downstream of the counter balance valve. A bypass valve is provided so that the discharge side communicates with the suction side of the hydraulic motor and the counter balance valve, and the bypass valve is incorporated in two spools urged to a neutral position by a pair of springs. The check valve has an opposing check valve, and when the two check valves are opened by two communication passages respectively communicating with the discharge side and the suction side of the counter balance valve, the discharge side of the counter balance valve Can communicate with the suction side of the hydraulic motor and the counter balance valve. The main spool biased to the neutral position by the ring is returned to the neutral position by the self-pressure of the pilot oil passage through the two throttles respectively connected to the two ports of the direction switching valve. The two choke drain oil passages communicate with the pilot oil passage through the two throttles, the throttle has an opening area larger than the choke, and the counterbalance valve main spring is the A biasing force stronger than a spring of the bypass valve is provided, and when the direction switching valve is neutral, the spool of the bypass valve returns to the neutral position later than the main spool of the counter balance valve. Hydraulic drive device to do. 前記絞りは前記カウンターバランス弁に内蔵され、前記チョークは前記バイパス弁に内蔵されたことを特徴とする請求項１記載の油圧駆動装置。 2. The hydraulic drive device according to claim 1, wherein the throttle is built in the counter balance valve, and the choke is built in the bypass valve.
JP2003411229A 2003-12-10 2003-12-10 Hydraulic drive Expired - Lifetime JP4263589B2 (en)

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR101188227B1 (en) 2011-09-02 2012-10-08 이능수 3-port multi directional valve
CN103557202A (en) * 2013-11-04 2014-02-05 中石化胜利油建工程有限公司 Unloading vibration reduction method and unloading vibration reduction loop for neutral position of high-flow electro-hydraulic directional control valve
JPWO2013179671A1 (en) * 2012-06-01 2016-01-18 パナソニックＩｐマネジメント株式会社 Device monitoring device, device monitoring system, registration terminal, and device monitoring method
CN107605826A (en) * 2017-10-16 2018-01-19 杭州诺祥科技有限公司 Spool valve core type balanced valve treadmill driving control system

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR101188227B1 (en) 2011-09-02 2012-10-08 이능수 3-port multi directional valve
JPWO2013179671A1 (en) * 2012-06-01 2016-01-18 パナソニックＩｐマネジメント株式会社 Device monitoring device, device monitoring system, registration terminal, and device monitoring method
CN103557202A (en) * 2013-11-04 2014-02-05 中石化胜利油建工程有限公司 Unloading vibration reduction method and unloading vibration reduction loop for neutral position of high-flow electro-hydraulic directional control valve
CN107605826A (en) * 2017-10-16 2018-01-19 杭州诺祥科技有限公司 Spool valve core type balanced valve treadmill driving control system

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