201124630 六、發明說明： 【發明所屬之技術領域】 本發明係關於-種例如射出成形機、壓力機械等之液壓 裝置。 【先前技術】 一般於大型射出成形機之油壓裝置中，保壓時射出氣缸 及油壓迴路之液體容積較大，因此於使油壓泵逆旋轉而進 行減£之情形時，減壓時間變長。該情況特別係於將2台 以上油壓泵合流而使油壓迴路之液體容積大容量化之情形 時顯著產生。 先刚，於合流2台以上油壓泵而構成之液壓裝置中，將 抓向機械之液壓油之流量大致設為零而僅將液壓油之壓力 保持為问壓時，為實現節能運轉，有時僅使丨台泵工作， 卸載剩餘之泵（參照曰本專利特開2〇〇9_174572號公報：專 利文獻1)。於該液壓裝置中，以使主泵之負載壓力不會逆 μ至已卸載泵中之方式於卸载泵之喷出側設置止回閥。 、然而，於上述先前之液壓裝置中，當使較高之負載壓力 減壓時，由於在安裝有止回閥之泵中無法逆流，因此僅使 1台主泵逆流而進行減壓動作。大型機械之負載液體之迴 路容積大，由1台主泵控制減壓，響應速度非常緩慢。 假設不設置止回閥而使數台泵同時運轉’則減壓亦由數 台泵進行，故可相對較快地減壓，但於不需要大流量時無 法卸載不必要之泵，故而無法實現節能運轉。 [先前技術文獻]BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic device such as an injection molding machine, a press machine, or the like. [Prior Art] Generally, in the hydraulic device of a large-scale injection molding machine, the liquid volume of the cylinder and the hydraulic circuit is large when the pressure is maintained, so when the hydraulic pump is reversely rotated to reduce the pressure, the decompression time is lengthen. This is particularly the case when two or more hydraulic pumps are combined to increase the volume of the liquid in the hydraulic circuit. Firstly, in a hydraulic device composed of two or more hydraulic pumps, the flow rate of the hydraulic oil that grabs the machine is set to zero, and only the pressure of the hydraulic oil is maintained as a pressure, in order to achieve energy-saving operation, In the meantime, only the pump is operated, and the remaining pump is unloaded (refer to Japanese Laid-Open Patent Publication No. Hei. No. Hei. No. Hei. In the hydraulic device, a check valve is provided on the discharge side of the unloading pump so that the load pressure of the main pump does not reverse μ to the unloaded pump. However, in the above-described prior art hydraulic device, when the high load pressure is reduced, since the pump cannot be reversely flowed in the pump in which the check valve is attached, only one main pump is reversely flowed to perform the pressure reducing operation. The large-scale mechanical load liquid has a large return volume, and is controlled by a main pump to reduce pressure, and the response speed is very slow. Assuming that several pumps are operated at the same time without setting a check valve, the decompression is also performed by several pumps, so that the pressure can be decompressed relatively quickly, but the unnecessary pump cannot be unloaded when a large flow rate is not required, so that it cannot be realized. Energy-saving operation. [Previous Technical Literature]
S 151771.doc 201124630 [專利文獻] [專利文獻1]曰本專利特開2009-174572號公報 【發明内容】 [發明所欲解決之問題] 因此，本發明之課題在於提供一種特別是於致動器趣路 等液體容積較大之大型機械中，亦可使減壓高速化之液壓 裝置。 ^ [解決問題之技術手段] 為解決上述課題，本發明之液壓裝置之特徵在於包括. .第1系’其可於雙方向上旋轉且可於雙方向上喷出液 弟i馬達，其正反驅動上述第1泵； 第1止回閥，其以自上述第丨泵之流動成為正向之方式設 置於連接於上述第1泵之第1線上； :壓間’其藉由上述第!線之較上述第^回間更上游側 。^刀之壓力、及上述第〗線之較上述 分夕颅a w岡更下游側部 之“而動作，當自上述下游側部 游側部分之昼力的值大於固定值時，排出上=上逑上 之液體； ” _出上述下游側部分 壓力感測器，其檢測上述第!線 力；以及 上这下游側部分之壓 控制部，其根據由上述屋力感測器 目標壓力，以μ、+、认.，ΓΤ J出之測壓力與 上述第丨馬達。 、目t屋力之方式控制 151771.doc 201124630 根據本發明之液壓裝置，上述差壓閥係當自上述第】線 之下游側部分之壓力減去上述第丨線之上游側部分之壓力 的值大於固疋值時’排出上述下游側部分之液體，因此當 第1泵正旋轉時，上游側部分之壓力大於下游側部分之壓 力，第1止回閥打開，差壓閥不工作。 另一方面，於保壓時等之下游側部分之壓力大於上游側 部T之壓力而使得第丨止回閥閉鎖的狀態下，上述檢測壓 力高於上述目標壓力，當進行第丨線之減壓時，上述控制 部係使第!泵逆旋轉而排出上游側部分之液體。如此，自 下游側部分之愿力減去上游側部分之壓力的值大於固定 值，差壓閥工作而排出下游側部分之液體。 如此，藉由差壓閥之減壓，自較上述閉鎖狀態之第i止 回閥更下游側之容積相對較小的液體迴路之部分排出液 體，因此可縮短減壓時間。特別是於負載側之液體容積較 大之大型機械之液壓裝置中，可使減壓動作顯著高速化。 又，於一實施形態之液壓裝置中，包括： 第2泵； 第2馬達’其驅動上述第2录； 第2止回間，其以自上述第巧向上述第1線之流動成為 正向之方式’設置於連接上述第i線之上述上游側部分斑 上述第2泵之第2線上；且 〇 上述控制部係當判斷出僅運轉上述第丨泵便可使所需要 流量之液體喷出至上述第遞時，停止運轉上述第2栗，另 一方面，當判斷出僅運轉上述第丨泵無法使所需要流量之 151771.doc 201124630 液體喷出至上述第1線時，開始運轉上述第2泵。 根據該實施形態之液壓裝置，上述控制部係當判斷出僅 運轉上述第1泵便可使所需要流量之液體喷出至上述第1線 時，停止運轉上述第2泵，另一方面，當判斷出僅運轉上 述第1泵無法使所需要流量之液體喷出至上述第丨線時，開 始運轉上述第2泵，因此可實現節能運轉。 又，當運轉第1泵並停止運轉第2泵時，第丨線上之液體 藉由第2止回閥而不會逆流至第2泵。於該狀態下，由差壓 闊進行減壓時’自已閉鎖之第丨止回閥之下游側由差壓閥 排出液體，因此液體之排出側之迴路（較第丨止回閥更下游 側之迴路）之容積相對較小，可快速減壓，且可進行高精 度之壓力控制。 又’於一實施形態之液壓裝置中， 於連接上述苐1線之上述上游側部分與上述差壓閥之第4 線上，設置節流部； 於上述第4線之上述節流部與上述差壓閥之間的部分， 連接有液控溢流閥。 根據該實施形態之液壓裝置，於上述第4線之上述節流 部與上述差壓閥之間的部分，連接有液控溢流閥’因此若 較第1止回閥更上游側之第1線之上游側部分之壓力高於溢 流閥之設定壓，則溢流閥打開。如此，第4線之節流部與 差壓閥之間的部分之液體壓力降低，自第丨線之下游側部 刀的壓力減去第4線之節流部與差壓閥之間的部分的壓力 的值大於固定值，差壓閥工作而排出下游側部分之液體。 151771.doc 201124630 如此，可對差壓閥追加作為安全閥之功能。 [發明之效果] 根據本發明之液壓裝置，上述差壓閥係當自上述第1線 之下游側部分之壓力減去上述第1線之上游側部分之壓力 的值大於固定值時’排出上述下游側部分之液體，因此特 別是於負載侧之液體容積較大之大型機械之液壓裝置中， 亦可使減壓高速化’且可進行高精度之壓力控制。 【實施方式】 以下’根據圖示之實施形態，對本發明加以詳細說明。 (第1實施形態） 圖1係表示本發明之液壓裝置之第1實施形態之簡略構成 圖°玄液壓裝置包括連接於主機油壓迴路5之第1油壓源 1、第2油壓源2及第3油壓源3。該主機油壓迴路5係例如射 出成形機或壓力機械等之油壓裝置。 上述第1油壓源1係經由第丨線⑺連接於主機油壓迴路5。 上述第2油壓源2係經由第2線20連接於第1線10。上述第3 油壓源3係經由第3線30連接於第2線20。 上述第1油壓源1包括第1泵11、驅動該第丨泵丨丨之第^馬 達12、檢測該第1馬達12之旋轉角之編碼器13、及控制該 第1馬達12之第1控制器14。 上述第1泵11為例如固定容量型油壓泵，於雙方向上旋 轉且於雙方向上喷出液壓油 上述第1馬達1 2為例如伺服[Patent Document 1] [Patent Document 1] JP-A-2009-174572 SUMMARY OF INVENTION [Problem to be Solved by the Invention] Therefore, an object of the present invention is to provide an actuator, in particular, to actuate In a large-scale machine with a large liquid volume such as a fun road, it is also possible to reduce the pressure of the hydraulic device. [Technical means for solving the problem] In order to solve the above problems, the hydraulic device of the present invention is characterized in that the first system is capable of rotating both sides upward and ejecting the liquid motor i in both directions, and the front and rear drives are driven. The first pump; the first check valve is disposed on a first line connected to the first pump so that a flow from the second pump is positive; and the pressure is 'by the first line It is more upstream than the above-mentioned second back. ^The pressure of the knife, and the above-mentioned line of the lower part of the lower part of the lower part of the skull, and the action of the lower side of the side of the downstream side of the side of the side of the side of the force is greater than a fixed value, the discharge on = up a liquid on the crucible; _ out the downstream side partial pressure sensor, which detects the above-mentioned first line force; and a pressure control portion on the downstream side portion, which is based on the target pressure of the above-mentioned house sensor, to μ , +, recognize., ΓΤ J out of the measured pressure and the above-mentioned third motor. According to the hydraulic device of the present invention, the differential pressure valve is a value obtained by subtracting the pressure of the upstream side portion of the second ridge line from the pressure of the downstream side portion of the ray line. When the value is larger than the solid value, the liquid in the downstream side portion is discharged. Therefore, when the first pump is rotating, the pressure of the upstream side portion is greater than the pressure of the downstream side portion, the first check valve is opened, and the differential pressure valve is not operated. On the other hand, in a state where the pressure of the downstream side portion at the time of holding pressure or the like is greater than the pressure of the upstream side portion T so that the third check valve is closed, the above-mentioned detection pressure is higher than the target pressure, and the decompression of the second line is performed. At this time, the control unit reversely rotates the first pump to discharge the liquid in the upstream side portion. Thus, the value of the pressure from the downstream side portion minus the upstream side portion is larger than a fixed value, and the differential pressure valve operates to discharge the liquid in the downstream side portion. As described above, by the pressure reduction of the differential pressure valve, the liquid is discharged from the portion of the liquid circuit having a relatively small volume on the downstream side of the ith check valve in the above-described closed state, so that the pressure reduction time can be shortened. In particular, in a hydraulic device of a large machine having a large liquid volume on the load side, the decompression operation can be significantly speeded up. Further, in the hydraulic device according to the embodiment, the second pump includes: a second pump that drives the second record; and a second check that is forward from the first line to the first line The method is such that the upstream portion of the i-th line is connected to the second line of the second pump; and the control unit determines that only the third pump is operated to eject the liquid of the required flow rate. At the time of the first delivery, the operation of the second chest is stopped, and when it is determined that only the first pump is operated, the liquid of the required flow rate of 151771.doc 201124630 is discharged to the first line, and the operation is started. 2 pumps. According to the hydraulic device of the embodiment, the control unit stops the operation of the second pump when it is determined that only the first pump is operated to discharge the liquid of the required flow rate to the first line. It is determined that the operation of the second pump is started only when the first pump is not able to discharge the liquid of the required flow rate to the second line, so that the energy-saving operation can be realized. Further, when the first pump is operated and the second pump is stopped, the liquid on the second line does not flow back to the second pump by the second check valve. In this state, when the pressure is reduced by the differential pressure, the liquid is discharged from the differential pressure valve on the downstream side of the self-locking check valve, so the circuit on the discharge side of the liquid (the downstream side of the third check valve) The circuit has a relatively small volume, can be quickly decompressed, and can perform high-precision pressure control. Further, in the hydraulic device according to the embodiment, the throttle portion is provided on the fourth line connecting the upstream side portion of the first line and the differential pressure valve; and the throttle portion on the fourth line is different from the above A portion between the pressure valves is connected to a hydraulically controlled relief valve. According to the hydraulic device of the embodiment, the hydraulic control relief valve is connected to the portion between the throttle portion and the differential pressure valve of the fourth line, so that the first upstream check valve is the first one. The pressure at the upstream side of the line is higher than the set pressure of the relief valve, and the relief valve opens. Thus, the liquid pressure in the portion between the throttle portion of the fourth line and the differential pressure valve is lowered, and the portion between the throttle portion of the fourth line and the differential pressure valve is subtracted from the pressure of the downstream side cutter of the second winding line. The value of the pressure is greater than a fixed value, and the differential pressure valve operates to discharge the liquid in the downstream side portion. 151771.doc 201124630 In this way, the differential pressure valve can be added as a safety valve. According to the present invention, in the hydraulic device of the present invention, when the value of the pressure from the downstream side portion of the first line minus the pressure of the upstream side portion of the first line is larger than a fixed value, the discharge valve is discharged. Since the liquid in the downstream side portion is particularly large in the hydraulic device of a large machine having a large liquid volume on the load side, the pressure reduction can be accelerated, and high-precision pressure control can be performed. [Embodiment] Hereinafter, the present invention will be described in detail based on the embodiments shown in the drawings. (First Embodiment) Fig. 1 is a schematic view showing a first embodiment of a hydraulic device according to the present invention. The first hydraulic pressure device includes a first hydraulic source 1 and a second hydraulic source 2 connected to a main hydraulic circuit 5. And the third hydraulic source 3. The main hydraulic circuit 5 is, for example, a hydraulic device such as an injection molding machine or a press machine. The first hydraulic source 1 is connected to the main hydraulic circuit 5 via a second winding (7). The second hydraulic source 2 is connected to the first line 10 via the second line 20. The third hydraulic source 3 is connected to the second line 20 via the third line 30. The first hydraulic pressure source 1 includes a first pump 11, a first motor 12 that drives the second pump, an encoder 13 that detects a rotation angle of the first motor 12, and a first one that controls the first motor 12. Controller 14. The first pump 11 is, for example, a fixed displacement hydraulic pump, and both of them are rotated upward and both of the hydraulic oil is discharged upward. The first motor 1 2 is, for example, a servo.
檢測由上述編碼器13檢測出之旋轉角，一 一面控制第1馬達 151771.doc 201124630 12之旋轉速度，藉此自第1泵11控制流量而噴出液壓油。 同樣上述第2油壓源2包括第2泵21、驅動該第2泵21之第 2馬達22、檢測該第2馬達22之旋轉角之編碼器23、及控制 該第2馬達22之第2控制器24。 上述第3油壓源3包括第3系31、驅動該第3系31之第3馬 達32、檢測該第3馬達32之旋轉角之編碼器33、及控制該 第3馬達32之第3控制器34。 上述第2泵21及上述第3系31既可為於一方向上旋轉於另 一方向上喷出液壓油之果，或者亦可為於雙方向上旋轉且 於雙方向上噴出液壓油之泵。 上述第1泵11連接於第1線1 〇及槽4。於該第〖線丨〇上，以 自第1泵11向主機油壓迴路5之流動成為正向之方式設置有 第1止回閥1 5。 以藉由上述第1線10之較上述第丨止回閥15更上游側部分 l〇a之壓力Pa、及上述第^線⑺之較上述第i止回閥15更下 游側部分i〇b之壓力Pb而工作之方式設置有差壓閥6。此 處，所謂「上游側」係指第正旋轉，而自㈣"噴 出之液壓油自第1泵11向主機油壓迴路5流動時之上游側。 該差壓閥6係當自上述下游側部分⑽之下游側壓力抑減 去上述上游側部分i 〇 a之上游側壓力p a的值大於固定值 時’排出上述下游側部分10b之液壓油。 具體而言，於差麗閥6之彈菁室連接有上游側部分心， 於差墨闕6之主室連接有下游側部分⑽，差壓，係以如 下之方式構成：將打開自上游側部分⑽向下游側部分_ 151771.doc 201124630 之第1止回閥15之正方向的流動閉鎖，另一方面，當第^止 回閥15之上下游產生壓力差時將其反方向之流動打開。若 自下游側壓力Pb減去上游側壓力1>3之值大於彈簧室之彈菁 壓力Ps(固定值）((pb-pa)>ps)，則下游側部分1〇b連接於槽 4 〇 設置壓力感測器7，以檢測上述第1線1〇之下游側部分 l〇b之壓力Pb。上述第1控制器14係根據由上述壓力感測器 7檢測出之檢測壓力Pb及與壓力指令”相對應之目標壓 力，以上述檢測壓力Pb成為上述目標壓力之方式控制上述 第1馬達12。第1控制器14係將上述檢測壓力pb輸出至壓力 監控器。 上述第1控制器14、上述第2控制器24及上述第3控制器 34構成控制部50。 該控制部50係當判斷出僅運轉上述第i泵丨丨便可使所需 要流量之液壓油喷出至上述第1線1〇時，停止運轉上述第 2、上述第3泵21、31，另一方面，當判斷出僅運轉上述第 1泵11無法使所需要流量之液壓油喷出至上述第1線10時， 開始運轉上述第2泵21或上述第3泵31中之至少一者。該控 制部50之控制方法為例如日本專利特開2009-1 74572號公 報或日本專利第43417 19號公報中所記載之控制方法，當 然亦可為其他控制方法。 上述第1控制器14接受1個壓力指令Pi、1個流量指令Qi 及表示來自上述壓力感測器7之檢測壓力之信號，輸出為 獲传上述壓力指令Pi及與流量指令Qi相對應之目標壓力以 151771.doc 201124630 及目標流量之操作量。 並且，當該操作量為預先規定之設定值以下時，上述第 1控制器1 4對應於操作量將流量改變之液壓油連續地噴出 至上述第1泵11，並且為使液壓油不喷出至上述第2泵21， 而不將下位流量指令Q!輸出至上述第2控制器24。又，上 述第2控制器24為使液壓油不噴出至上述第3泵31 ,而不將 下位流量指令Q2輸出至上述第3控制器34。此處，所謂 「預先規定之設定值」通常係指各油壓源之最大噴出流 量。 另一方面’當上述操作量超過上述設定值時，上述第1 控制器14係以上述第丨、上述第2泵11、以之喷出流量之合 計流量對應於上述操作量連續地改變，並且上述第1、上 述第2泵11、21分別噴出液壓油之方式，將下位流量指令 Qi輸出至上述第2控制器24。又，上述第2控制器24係於判 斷出上述第丨、上述第2泵11、21之噴出流量之合計流量小 於上述操作量之情形時，以使上述第3泵31可動之方式’ 將下位流量指令&輸出至上述第3控制器。 再者，上述第1控制器14亦可以上述第丨、上述第2、上 述第3泵11、21、3 1之噴出流量之合計流量對應於上述操 作量連續地改變，並且上述第丨、上述第2、上述第3泵 11、21、3 1分別噴出液壓油之方式，將下位流量指令α、 Q2輸出至上述第2、上述第3控制器24、34。 上述第2泵21連接於第2線20及槽4。該第2線2〇將上述第 1線1〇上之上游側部分l〇a與第2泵21連接。於該第2線2〇 15l771.doc 201124630 上，以自第2栗21向第1線10之流動成為正向之方式設置有 第2止回閥25。 上述第3泵31連接於第3線30及槽4。該第3線30將上述第 2線20上之第2止回閥25之下游側部分與第3泵31連接。於 該第3線30上，以自第3泵31向第2線20之流動成為正向之 方式設置有第3止回閥35。 其次’對上述構成之液壓裝置之作用進行說明。 當將液壓油自上述第1、上述第2、上述第3泵U、21、 31輸送至上述主機油壓迴路5時，來自上述第1、上述第 2、上述第3泵11、21、31之液壓油如虛線箭頭所示，合流 並於正方向流動。此時，第丨線丨〇之上游側部分丨〇a之壓力 Pa大於第1線1〇之下游側部分i〇b之壓力pb，第1止回閥 打開，差壓閥6不工作。 並且，將流向主機油壓迴路5之液壓油之流量大致設為 令僅將液壓油之廢力保持為高墨時，藉由控制部5〇停止 第2、第3泵21、3 1而僅使第1泵丨丨單獨運轉，可實現節能 運轉。此時，第1泵11之負載壓力藉由第2、第3止回閥 25、35之作用未逆流至已卸載之第2、第3泵21、31。 另一方面，於保壓時等之下游側部分1〇b之壓力pb大於 上游側部分1 〇a之壓力pa而閉鎖第i止回閥丨5的狀態下，上 述檢測壓力高於上述目標壓力，當進行上述主機油壓迴路 5及上述第1線1 〇之減壓時，上述第丨控制器丨4係使第1泵u 逆方疋轉，將上游側部分1 〇a之液壓油如實線箭頭Qp所示排 出至槽4側。如此，自下游側部分1〇b之壓力朴減去上游側 15177l.doc 201124630 部分10a之壓力pa的值大於固定值，差壓閥6工作。並且， 藉由該差壓閥6之工作，下游側部分1〇b之液壓油如實線箭 頭Qr所示排出至槽4側。再者，上游側部分1〇a之液壓油藉 由第2、第3止回閥25、35之作用未逆流至第2、第3泵21、 3 1 ° 因此，如圖2所示，藉由上述第丨泵丨丨之逆旋轉，可自第 1泵11僅少量排出上游側部分10a内之液壓油之排出量， 且藉由差壓閥6之工作，可自差壓閥6大量排出下游側部分 l〇b内之液壓油之排出量qr，可縮短降低下游側部分 10b(主機油壓迴路5)之壓力pb之時間。 作為比較例，係對未設置上述第丨止回閥15及上述差壓 閥6之液壓裝置之第1線1 〇(主機油壓迴路5)之降壓時間進行 說明。纟於僅藉Meu之逆旋轉排ώ第uu〇之液壓 /由故如圖3所示，自第1果！ ！之液壓油之排出量仏變多， 降低第1線10之壓力Pb之時間At2增加。 如此，藉由差壓閥6之減壓，自較上述閉鎖狀態之第丄止 回閥15更下游側之容積相對較小的液體迴路之部分排出液 壓油’故可縮短減壓時間。特別是於負載側之液體容積較 大之大型機械之液壓裝置中’可使減壓動作顯著高速化。 又，於上述第1線10之上游側部分1〇a連接有第2線2〇， 於該第2線20連接有第3線3() ’故由差壓閥6進行減壓時， 自已閉鎖之第1止回閥15之下游側之下游側部分iQb由差壓 閥6排出液壓油，而不必自第2線2()或第3線3()排出液壓 油’即便液壓油之排出側之迴路（較第1止回闊15更下游側 151771.doc •13· 201124630 之迴路）之容積相對較大，亦可快速減壓，從而可同時實 現節能性與減壓之響應性能。 (第2實施形態） 圖4係表示本發明之液壓裝置之第2實施形態。若對與上 述第1實施形態不同之方面進行說明，則於該第2實施形態 中，在第1線10之上游側部分10a與差壓閥6之間，設置有 液控溢流閥8及節流部9。再者，於該第2實施形態中，對 與上述第1實施形態相同之部分附加相同之參照編號，並 省略詳細說明。 如圓4所示，於將第1線1〇之上游側部分1〇a與差壓閥6之 彈簧至連接之第4線40上，設置有節流部9。該節流部9發 揮如下作用：於第4線40之上游側部分10a與差壓閥6中之 壓力Pa之間產生差壓而使差壓閥6工作。 於上述第4線40之節流部9與差壓閥6之間的一部分，連 接有液控溢流閥8。當該第4線40之一部分的壓力大於液控 溢流閥8之彈簧室之彈簧壓力時，將第4線4〇之一部分朝向 槽4打開。 根據上述構成之液壓裝置，由於在上述第4線4〇之上述 一部分連接有液控溢流閥8，故若較第i止回閥15更上游側 之第1線10之上游側部分10a的壓力高於液控溢流閥8之設 定壓’則液控溢流閥8打開。如此，第4線4〇之上述一部分 之液壓油之壓力降低，自第丨線⑺之下游側部分i〇b之壓力 減去第4線40之上述一部分之壓力的值大於固定值，差壓 閥6工作。並且，藉由差壓閥6之工作，下游側部分丨叽之 151771.doc •14- 201124630 液壓油排出至槽4側。 因此，可對上述差壓閥6追加作為安全閥之功能。又， 上述溢流閥8亦可為液控溢流閥，故而可小型化。 再者，本發明並不限定於上述實施形態。例如，上述液 壓裝置亦可為除處理液壓油以外還處理水等液體之裝置。 又，亦可不設置上述第2、上述第3油壓源2、3而僅設置上 述第1油壓源1，藉由上述差壓閥6之減壓，可縮短減壓 間。 又，上述第1油壓源1以外之油壓源2、3之數量之增減為 任意。又，構成上述控制部50之控制器14、24、34之數量 之增減為任意。又’亦可不設置上述第2、上述第3止回閥 25 ' 35 ° 【圖式簡單說明】 圖1係表示本發明之液壓裝置之第丨實施形態之簡略構 圖； 圖2係說明本發明之液壓裝置之降壓時間之縮短的說 圖； ". 圖3係說明比較例之液壓裝置之降壓時間之增加的 圖；及 s 1明 圖4係表示本發明之液壓裝置之第2實施形態之簡略構成 圖0 【主要元件符號說明】 1 第1油壓源 2 第2油壓源 151771.doc -15- 201124630 3 第3油壓源 4 槽 5 主機油壓迴路 6 差壓閥 7 壓力感測器 8 液控溢流閥 9 節流部 10 第1線 10a 第1線之上游側部分 10b 第1線之下游側部分 11 第1泵 12 第1馬達 13 ' 23 ' 33 編碼 14 第1控制器 15 第1止回閥 20 第2線 21 第2泵 22 第2馬達 24 第2控制器 25 第2止回閥 30 第3線 31 第3泵 32 第3馬達 34 第3控制器 151771.doc -16- 201124630 35 第3止回閥 40 第4線 50 控制部 Pa 上游側壓力 Pb 下游側壓力 Pi 壓力指令 Ps 彈簧壓力（固定值） Qi ' Qi 下位流量指令 Qi 流量指令 Qp、Qr 貫線前頭 151771.docThe rotation angle detected by the encoder 13 is detected, and the rotation speed of the first motor 151771.doc 201124630 12 is controlled to control the flow rate from the first pump 11 to discharge the hydraulic oil. Similarly, the second hydraulic source 2 includes a second pump 21, a second motor 22 that drives the second pump 21, an encoder 23 that detects a rotation angle of the second motor 22, and a second controller that controls the second motor 22. Controller 24. The third hydraulic source 3 includes a third system 31, a third motor 32 that drives the third system 31, an encoder 33 that detects a rotation angle of the third motor 32, and a third control that controls the third motor 32. 34. The second pump 21 and the third system 31 may be configured to eject hydraulic oil in one direction in the other direction, or may be a pump that both rotate upward and discharge hydraulic oil in both directions. The first pump 11 is connected to the first wire 1 and the groove 4. In the above-mentioned line, the first check valve 15 is provided so that the flow from the first pump 11 to the main hydraulic circuit 5 becomes positive. The pressure Pa of the upstream side portion 10a of the first line 10 is higher than the first check valve 15 and the downstream side portion i〇b of the first line (7) with respect to the ith check valve 15 The differential pressure valve 6 is provided in such a manner that the pressure Pb is operated. Here, the "upstream side" means the first rotation, and the hydraulic oil discharged from (4) " is discharged from the first pump 11 to the upstream side of the main hydraulic circuit 5. The differential pressure valve 6 is a hydraulic oil that discharges the downstream side portion 10b when the pressure from the downstream side of the downstream side portion (10) is decreased and the value of the upstream side pressure p a of the upstream side portion i 〇 a is larger than a fixed value. Specifically, the upstream side core is connected to the elastic chamber of the differential valve 6, and the downstream side portion (10) is connected to the main chamber of the differential ink cartridge 6, and the differential pressure is configured in such a manner that it will be opened from the upstream side. Part (10) is blocked in the forward direction of the first check valve 15 of the downstream side portion _ 151771.doc 201124630, and on the other hand, when the pressure difference is generated upstream and downstream of the check valve 15, the flow in the opposite direction is opened. . If the value of the upstream side pressure Pb minus the upstream side pressure 1 > 3 is larger than the spring chamber pressure Ps (fixed value) ((pb - pa) > ps), the downstream side portion 1 〇 b is connected to the groove 4 The pressure sensor 7 is provided to detect the pressure Pb of the downstream side portion 10b of the first line 1〇. The first controller 14 controls the first motor 12 such that the detected pressure Pb becomes the target pressure based on the detected pressure Pb detected by the pressure sensor 7 and the target pressure corresponding to the pressure command. The first controller 14 outputs the detected pressure pb to the pressure monitor. The first controller 14, the second controller 24, and the third controller 34 constitute a control unit 50. The control unit 50 determines that When only the first pump 运转 is operated, the hydraulic oil of the required flow rate can be discharged to the first line 1 ,, the second and second pumps 21 and 31 can be stopped, and when only the third pump 21 and 31 are operated, When the first pump 11 is not able to discharge the hydraulic oil of the required flow rate to the first line 10, at least one of the second pump 21 or the third pump 31 is started to operate. The control method of the control unit 50 For example, the control method described in Japanese Patent Laid-Open Publication No. 2009-1 74572 or Japanese Patent No. 43417 19 may be another control method. The first controller 14 receives one pressure command Pi and one. The flow command Qi and the representation come from The signal of the detected pressure of the pressure sensor 7 is outputted to receive the pressure command Pi and the target pressure corresponding to the flow command Qi with an operation amount of 151771.doc 201124630 and the target flow rate. When the predetermined value is equal to or less than the predetermined value, the first controller 14 continuously discharges the hydraulic oil whose flow rate is changed to the first pump 11 in accordance with the operation amount, and does not discharge the hydraulic oil to the second pump 21, but The lower flow rate command Q! is not output to the second controller 24. Further, the second controller 24 does not discharge the hydraulic oil to the third pump 31, and does not output the lower flow rate command Q2 to the third control. Here, the "predetermined set value" generally means the maximum discharge flow rate of each hydraulic source. On the other hand, when the operation amount exceeds the set value, the first controller 14 continuously changes the total flow rate of the discharge flow rate by the first and second pumps 11, and the flow rate continuously changes according to the operation amount, and The first and second pumps 11 and 21 respectively discharge hydraulic oil, and the lower flow rate command Qi is output to the second controller 24. Further, when the second controller 24 determines that the total flow rate of the discharge flow rates of the second and second pumps 11 and 21 is smaller than the operation amount, the second controller 24 is configured to move the third pump 31 to the lower position. The flow command & output is output to the third controller described above. Further, the first controller 14 may continuously change the total flow rate of the discharge flow rates of the second, the second, and third pumps 11, 21, and 31, corresponding to the operation amount, and the third and the The second and fourth pumps 11, 21, and 31 respectively discharge the hydraulic oil, and output the lower flow rate commands α and Q2 to the second and third controllers 24 and 34. The second pump 21 is connected to the second wire 20 and the groove 4. The second line 2〇 connects the upstream side portion 10a of the first line 1〇 to the second pump 21. In the second line 2〇15l771.doc 201124630, the second check valve 25 is provided so that the flow from the second pump 21 to the first line 10 becomes positive. The third pump 31 is connected to the third wire 30 and the groove 4. The third line 30 connects the downstream side portion of the second check valve 25 on the second line 20 to the third pump 31. In the third line 30, the third check valve 35 is provided so that the flow from the third pump 31 to the second line 20 becomes positive. Next, the action of the hydraulic device having the above configuration will be described. When the hydraulic oil is sent from the first, second, and third pumps U, 21, and 31 to the main hydraulic circuit 5, the first, second, and third pumps 11, 21, and 31 are supplied. The hydraulic oil, as indicated by the dashed arrows, merges and flows in the positive direction. At this time, the pressure Pa of the upstream side portion 丨〇a of the second turn line is larger than the pressure pb of the downstream side portion i〇b of the first line 1〇, the first check valve is opened, and the differential pressure valve 6 is not operated. Further, when the flow rate of the hydraulic oil flowing to the main hydraulic circuit 5 is set such that only the waste force of the hydraulic oil is kept high, the control unit 5 stops the second and third pumps 21 and 31, and only The first pump 丨丨 is operated alone to achieve energy-saving operation. At this time, the load pressure of the first pump 11 is not reversed to the unloaded second and third pumps 21 and 31 by the action of the second and third check valves 25 and 35. On the other hand, in a state where the pressure pb of the downstream side portion 1b is larger than the pressure pa of the upstream side portion 1a, and the i-th check valve 丨5 is closed, the above-described detection pressure is higher than the target pressure. When the main hydraulic circuit 5 and the first line 1 are decompressed, the first controller 丨4 reverses the first pump u and the hydraulic oil of the upstream side 1 〇a is a solid line. It is discharged to the side of the groove 4 as indicated by the arrow Qp. Thus, the pressure from the downstream side portion 1b is reduced to the upstream side 15177l.doc 201124630 The pressure pa of the portion 10a is greater than a fixed value, and the differential pressure valve 6 operates. Further, by the operation of the differential pressure valve 6, the hydraulic oil of the downstream side portion 1b is discharged to the side of the groove 4 as indicated by the solid arrow Qr. Further, the hydraulic oil of the upstream side portion 1a does not flow back to the second and third pumps 21, 31 by the action of the second and third check valves 25, 35. Therefore, as shown in Fig. 2, By the reverse rotation of the second pump ,, only the amount of hydraulic oil discharged from the upstream side portion 10a can be discharged from the first pump 11 by a small amount, and the differential pressure valve 6 can be discharged from the differential pressure valve 6 by the operation of the differential pressure valve 6. The discharge amount qr of the hydraulic oil in the downstream side portion 10b can shorten the time for lowering the pressure pb of the downstream side portion 10b (main oil pressure circuit 5). As a comparative example, the step-down time of the first line 1 〇 (main hydraulic circuit 5) of the hydraulic device in which the above-described second check valve 15 and the differential pressure valve 6 are not provided will be described.纟 仅 仅 M M M M M M M M M M M M M M M M M M M M M M M M M M ! The discharge amount of the hydraulic oil is increased, and the time At2 at which the pressure Pb of the first line 10 is lowered is increased. As described above, by the pressure reduction of the differential pressure valve 6, the hydraulic pressure is discharged from the portion of the liquid circuit which is relatively smaller on the downstream side than the third check valve 15 in the above-described closed state, so that the pressure reduction time can be shortened. In particular, in a hydraulic device of a large machine having a large liquid volume on the load side, the pressure reducing operation can be significantly increased. Further, the second line 2〇 is connected to the upstream side portion 1〇a of the first line 10, and the third line 3()′ is connected to the second line 20, so that the pressure is reduced by the differential pressure valve 6 The downstream side portion iQb of the downstream side of the first check valve 15 that is blocked is discharged by the differential pressure valve 6 without discharging the hydraulic oil from the second line 2 () or the third line 3 () even if the hydraulic oil is discharged The side circuit (compared to the first checkout wide 15 and the downstream side 151771.doc •13·201124630) has a relatively large volume and can be quickly decompressed, so that energy-saving and decompression response can be achieved at the same time. (Second Embodiment) Fig. 4 shows a second embodiment of the hydraulic device according to the present invention. In the second embodiment, a liquid pressure relief valve 8 is provided between the upstream side portion 10a of the first line 10 and the differential pressure valve 6 in the second embodiment. Throttling section 9. In the second embodiment, the same reference numerals are given to the same portions as those in the first embodiment, and the detailed description thereof will be omitted. As shown by the circle 4, the throttle portion 9 is provided on the fourth line 40 connecting the upstream side portion 1A of the first line 1 to the spring of the differential pressure valve 6 to the fourth line 40. The throttle unit 9 functions to generate a differential pressure between the upstream side portion 10a of the fourth line 40 and the pressure Pa in the differential pressure valve 6 to operate the differential pressure valve 6. A portion of the throttle line 9 between the fourth line 40 and the differential pressure valve 6 is connected to the pilot pressure relief valve 8. When the pressure of one of the fourth wires 40 is greater than the spring pressure of the spring chamber of the pilot relief valve 8, a portion of the fourth wire 4 turns toward the slot 4. According to the hydraulic device of the above configuration, the liquid-pressure relief valve 8 is connected to the portion of the fourth line 4, so that the upstream side portion 10a of the first line 10 on the upstream side of the first-th check valve 15 is The pressure is higher than the set pressure of the pilot operated relief valve 8 and the pilot operated relief valve 8 is opened. Thus, the pressure of the hydraulic oil of the above-mentioned part of the fourth line 4〇 is lowered, and the value of the pressure from the pressure of the downstream side portion i〇b of the second twist line (7) minus the portion of the fourth line 40 is greater than a fixed value, and the differential pressure Valve 6 works. Further, by the operation of the differential pressure valve 6, the downstream side portion 151771.doc • 14-201124630 hydraulic oil is discharged to the side of the tank 4. Therefore, the function of the safety valve can be added to the differential pressure valve 6. Further, since the relief valve 8 can also be a hydraulically controlled relief valve, it can be downsized. Furthermore, the present invention is not limited to the above embodiment. For example, the above-described hydraulic device may be a device that treats a liquid such as water in addition to the hydraulic oil. Further, the first hydraulic pressure source 1 may be provided without providing the second and third hydraulic pressure sources 2, 3, and the pressure reduction between the differential pressure valves 6 may be shortened. Further, the number of hydraulic pressure sources 2, 3 other than the first hydraulic source 1 is increased or decreased. Further, the number of controllers 14, 24, 34 constituting the control unit 50 is increased or decreased. Further, the second and third check valves 25' 35 ° may be omitted. FIG. 1 is a schematic view showing a third embodiment of the hydraulic device of the present invention; FIG. 2 is a view showing the present invention. FIG. 3 is a view for explaining an increase in the pressure reduction time of the hydraulic device of the comparative example; and FIG. 4 is a second embodiment of the hydraulic device of the present invention. Brief description of the structure Figure 0 [Description of main components] 1 1st hydraulic source 2 2nd hydraulic source 151771.doc -15- 201124630 3 3rd hydraulic source 4 tank 5 main hydraulic circuit 6 differential pressure valve 7 pressure Sensor 8 Hydraulically controlled relief valve 9 Throttle portion 10 First line 10a Upper side portion 10b of the first line Downstream side portion 11 of the first line First pump 12 First motor 13 ' 23 ' 33 Code 14 1 Controller 15 first check valve 20 second line 21 second pump 22 second motor 24 second controller 25 second check valve 30 third line 31 third pump 32 third motor 34 third controller 151771. Doc -16- 201124630 35 3rd check valve 40 4th line 50 Control part Pa upstream side pressure Pb downstream Pressure command Pi pressure spring pressure Ps (constant value) Qi 'flow rate command Qi lower flow rate command Qi Qp, Qr top intersecting line 151771.doc