1259112 (1) 玖、發明說明 【發明所屬之技術領域】 本發明有關一種液壓致動器，其具有 附著至該活塞桿之自由端之工具，且能夠 、一沖壓裝置等。更特別地是，本發明有 桿之複動型液壓致動器，及能夠爲一回復 該活垂桿 【先前技術】 一習知沖壓裝置包含一液壓致動器， 及一附者至該活塞桿之自由端之沖壓頭。 含一殻體，其藉著一垂直壁面分成一流體 液壓幫浦，其放置於該殻體中，以迫使該 之液壓流體藉著壓力進入該汽缸；一活塞 地裝在該汽缸中；及一活塞桿，其一端點 塞及另一端點部份由該殼體突出外面。該 作流體進給通道，其連接該殼體之流體槽 後方之汽缸之一後面部份；及一回流通道 及延伸在該活塞前面之汽缸之一前面部份 動器爲切削加工需要推進該活塞桿，及在 之後使該活塞桿回復至其原來位置。通常 動，藉著放置於該殻體中之回復彈簧移動 些案例中，當需要高力量使該活塞桿回復 ，難以藉著該回復彈簧使該活塞桿回復至 ~~活塞桿，及一 用作一切割裝置 關一種具有活塞 衝程確實地移動 其設有活塞桿， 該液壓致動器包 槽及一汽缸；一 流體槽中所包含 ，其可軸向滑動 部份連接至該活 殼體係設有一工 及延伸在該活塞 ，其連接該汽缸 。此習知液壓致 達成該切削加工 ，對於一回復運 該活塞桿。於一 至其原來位置時 其原來位置。 (2) 1259112 設若該液壓致動器之活塞桿固定一沖壓頭，以使用該 液壓致動器當作於鋼片中打孔之一沖壓裝置。當該鋼片係 厚的時或假如設計一沖壓裝置使得該沖壓頭及一沖壓孔間 之間隙係製成小，以更精確地沖壓出一孔洞時，該鋼片在 該沖壓頭上施加一高摩擦阻抗，並貫穿該鋼片抵住該活塞 桿之回復沖程，且於一些案例中，該活塞桿不能僅只藉著 一回復彈簧之彈性回復至其原來位置。當需要高回復力以 使該活塞桿回復至其原來位置時，一先前提出以使該活塞 桿回復至其原來位置之技術藉著諸如胺基甲酸酯橡膠管之 彈性構件圍繞該活塞桿。當該活塞桿推進時，該彈性構件 係彈性地壓縮，且該已壓縮彈性構件之彈性係用於由該沖 壓孔用力拉出該沖壓頭。然而，該已壓縮彈性構件之彈性 係不夠高，以致未能在該活塞桿上施加一充分之彈性回復 力，且該彈性構件阻礙該沖壓工作。 於日本專利第5 - 1 8 74 1 5號中提出之一複動型液壓致 動器係設有一活塞桿，並爲一回復衝程藉著工作流體迫使 該活塞桿移動。於此先前提出之複動型液壓致動器中，一 位置傳感器測量該活塞桿之位置及送出一代表該活塞桿位 置之位置信號至一自動通道選擇機構，根據該位置信號自 動地操作該自動選擇機構，以由一進給通道分開一幫浦機 構及將該幫浦機構連接至一回流通道，且藉此藉著該工作 流體之壓力強制地將該活塞桿回復至其原來位置。 於日本專利第5 - 1 8 7 4 1 5號中揭示之發明採用一位置 感測機制，其使用電子零件包含一極限開關、電螺管及一 -5- (3) 1259112 用於送出及接收位置信號之控制繼電器。該位置感測機制 具有一複雜之架構及易於發生故障。其可能因於一硬工件 中沖壓孔洞時所可能產生之震盪造成該極限開關發生故障 。使用各種電子零件之位置感測機制係亦昂貴的。 [發明內容】1259112 (1) Field of the Invention The present invention relates to a hydraulic actuator having a tool attached to a free end of the piston rod, and capable of, a punching device or the like. More particularly, the present invention has a lever-type double-acting hydraulic actuator, and can return the live lever. [Prior Art] A conventional stamping device includes a hydraulic actuator, and an attachment to the piston The stamping head of the free end of the rod. a housing comprising a fluid hydraulic pump by a vertical wall surface, which is placed in the housing to force the hydraulic fluid to enter the cylinder by pressure; a piston is mounted in the cylinder; The piston rod has an end plug and the other end portion protruded from the housing. The fluid feed passage is connected to a rear portion of one of the cylinders behind the fluid groove of the casing; and a return passage and a front portion of one of the cylinders extending in front of the piston are required to advance the piston for cutting The rod, and then the piston rod is returned to its original position. Usually moving, by moving the return spring placed in the housing, in some cases, when high force is required to restore the piston rod, it is difficult to return the piston rod to the ~~ piston rod by the return spring, and one used a cutting device is provided with a piston stroke that is surely moved to be provided with a piston rod, the hydraulic actuator and a cylinder; a fluid groove is included in the fluid chamber, and the axially sliding portion is coupled to the living housing. And extending the piston, which connects the cylinder. This conventional hydraulically achieves this cutting process and returns the piston rod for a return. Its original position when it is in its original position. (2) 1259112 If the piston rod of the hydraulic actuator is fixed to a punching head, the hydraulic actuator is used as a punching device for punching a hole in the steel sheet. The steel sheet is applied to the stamping head when the steel sheet is thick or if a punching device is designed such that the gap between the punching head and a punching hole is made small to more accurately punch a hole. The frictional resistance runs through the steel sheet against the return stroke of the piston rod, and in some cases, the piston rod cannot be returned to its original position only by the elasticity of a return spring. When a high restoring force is required to return the piston rod to its original position, a technique previously proposed to return the piston rod to its original position surrounds the piston rod by an elastic member such as a urethane rubber tube. When the piston rod is advanced, the elastic member is elastically compressed, and the elasticity of the compressed elastic member is used to force the punching head out of the punching hole. However, the elasticity of the compressed elastic member is not so high that a sufficient elastic restoring force is not applied to the piston rod, and the elastic member hinders the punching work. One of the double-acting hydraulic actuators proposed in Japanese Patent No. 5 - 1 74 74 15 is provided with a piston rod and forcibly moves the piston rod by a working fluid for a return stroke. In the above-mentioned double-acting hydraulic actuator, a position sensor measures the position of the piston rod and sends a position signal representing the position of the piston rod to an automatic passage selection mechanism, and automatically operates the automatic signal according to the position signal. The mechanism is selected to separate a pump mechanism from a feed passage and connect the pump mechanism to a return passage, and thereby forcibly return the piston rod to its original position by the pressure of the working fluid. The invention disclosed in Japanese Patent No. 5 - 1 8 7 4 15 uses a position sensing mechanism using electronic components including a limit switch, an electric solenoid and a -5- (3) 1259112 for sending and receiving. Control signal for position signal. This position sensing mechanism has a complex architecture and is prone to failure. It may be caused by a shock that may occur when punching a hole in a hard workpiece, causing the limit switch to malfunction. Position sensing mechanisms using various electronic components are also expensive. [Contents of the Invention]
本發明已由前面問題之觀點製成’且因此本發明之一 目的係提供一種設有簡單之活塞桿回復機制之複動型液壓 致動器，並能夠具有可靠性之操作且在一低成本下製成。The present invention has been made from the viewpoint of the foregoing problems' and thus it is an object of the present invention to provide a double-acting hydraulic actuator provided with a simple piston rod recovery mechanism, and capable of reliable operation and at a low cost Made under.
根據本發明之一論點’一複動型液壓致動器包含一殻 體，其藉著一垂直壁面分成一工作流體槽及一汽缸，及設 有一進給通道及一回流通道；一液壓幫浦’其放置於該殻 體中，以迫使該工作流體槽中所包含之工作流體藉著壓力 進入該汽缸；一電動馬達’其附著至該殼體以驅動該液壓 幫浦；一活塞，其可軸向滑動地裝在該汽缸中，並將該汽 缸之內部分成該進給通道所通入之一背面工作室及該回流 通道所通入之一前面工作室；及一活塞桿，其具有一連接 至該活塞之基底部份及一由該殼體突出外面之前面部份， 該致動器包括：一導引棒，其由該垂直壁面突出朝向該汽 缸，及在其前端設有一閥座，及一軸向閥導引孔；及一柱 型放泄閥，其具有一可軸向滑動地裝入該閥導引孔之閥桿 ，及於其後面部份設有一前面溝槽式部份及一由該前面溝 槽式部份隔開一預定距離之後面溝槽式部份，且一閥件固 定至該閥桿之前面部份及能夠安坐在該導引棒之閥座上； -6- (4) 1259112 其中該進給通道包括第一進給通道，其具有與該液壓幫浦 相通之一端點且通入該閥導引孔之另一端點，及第二進給 通道，其具有與該活塞後方之後面工作室相通之一端點及 通入該閥導引孔之另一端點；一小空間，其係藉著該垂直 壁面所圍繞，且一支撐該電動馬達之軸桿之軸承係形成於 該回流通道及該工作流體槽之間；該回流通道具有於該活 塞之前面通入該前面工作室之一端點及通入該閥導引孔之 另一端點；該前面溝槽式部份係用於連接該第一及該第二 進給通道，及由該第二進給通道分開該第一進給通道，且 該後面溝槽式部份係用於連接該第一進給通道及該回流通 道，由該回流通道分開該第一進給通道，連接該回流通道 及該小空間，及由該小空間分開該回流通道。 於根據本發明之複動型液壓致動器中，其較佳的是每 一前面及後面溝槽式部份係設有一預定寬度之環狀溝槽， 致使當該第一及第二進給通道之個別開放端點對應於該前 面溝槽式部份之環狀溝槽，及該第二進給通道係由第一進 給通道分開時，該回流通道藉著該後面溝槽式部份之環狀 溝槽與該工作流體槽相通，且當該第一進給通道及該回流 通道之個別開放端點對應於該後面溝槽式部份之環狀溝槽 時，該回流通道係由該小空間分開。 於根據本發明之複動型液壓致動器中，其較佳的是該 閥桿具有一突出進入該小空間之後面部份，及係在內部設 有一軸向回流通道。 1259112 【實施方式】According to one aspect of the invention, a double-acting hydraulic actuator includes a housing which is divided into a working fluid tank and a cylinder by a vertical wall surface, and is provided with a feed passage and a return passage; a hydraulic pump 'It is placed in the housing to force the working fluid contained in the working fluid tank to enter the cylinder by pressure; an electric motor 'which is attached to the housing to drive the hydraulic pump; a piston An axial sliding fit is mounted in the cylinder, and the interior of the cylinder is divided into a back working chamber through which the feeding passage is passed and a front working chamber into which the return passage is passed; and a piston rod having a piston rod a base portion connected to the piston and a front portion protruding from the outer surface of the casing, the actuator comprising: a guiding rod protruding from the vertical wall toward the cylinder, and a valve seat at a front end thereof And an axial valve guiding hole; and a column type bleed valve having a valve stem axially slidably inserted into the valve guiding hole, and a front groove portion at a rear portion thereof And one separated by the front grooved portion a grooved portion after a predetermined distance, and a valve member is fixed to the front portion of the valve stem and can sit on the valve seat of the guide rod; -6- (4) 1259112 wherein the feed passage includes a first feed passage having one end connected to the hydraulic pump and passing through the other end of the valve guide hole, and a second feed passage having one end communicating with the rear face of the piston Pointing into the other end of the valve guiding hole; a small space surrounded by the vertical wall, and a bearing supporting the shaft of the electric motor is formed in the return channel and the working fluid groove The return passage has a front surface of the piston that opens into one end of the front working chamber and another end that opens into the valve guide hole; the front grooved portion is used to connect the first and the a second feed channel, and the first feed channel is separated by the second feed channel, and the rear groove portion is for connecting the first feed channel and the return channel, and is separated by the return channel The first feed channel connecting the return channel and the small space , Separated by the small space and the return channel. In the double-acting hydraulic actuator according to the present invention, it is preferable that each of the front and rear grooved portions is provided with an annular groove of a predetermined width so that the first and second feeds are made. The individual open end points of the channel correspond to the annular groove of the front grooved portion, and when the second feed channel is separated by the first feed channel, the return channel passes through the rear grooved portion The annular groove is in communication with the working fluid groove, and when the first open end of the first feed channel and the return channel correspond to the annular groove of the rear groove portion, the return channel is This small space is separate. In the double-acting type hydraulic actuator according to the present invention, it is preferable that the valve stem has a surface portion which protrudes into the small space, and an axial return passage is provided inside. 1259112 [Embodiment]
參考圖1，其顯示根據本發明一較佳具體實施例中之 複動型液壓致動器，一電動馬達3係連接至一殼體2之後 面端點。該殼體2具有界定一工作流體槽5之幫浦殼體7 及使一後面端點接合至該電動馬達3，一垂直壁面4接合 至^卓浦威體7之則端，一汽缸殼體8接合至該垂直壁面 4之前端及界定一汽缸室，及一用於固持一工具及與該汽 缸殻體8 —體成形以便延伸在該汽缸殼體8下方之顎夾9 。一液壓幫浦6係放入該幫浦殼體7中。 一活塞1 0係可軸向滑動地裝入該汽缸殼體8。該汽 缸室係藉著該活塞10分成一前面工作室12，如在圖1左 邊所視，及一後面工作室1 3，如在圖1右邊所視。一活 塞桿11具有接合至該活塞10之基底部份，及一由該殼體 2經過該汽缸殼體8之前端突出向前之前面部份。Referring to Figure 1, there is shown a double acting hydraulic actuator in accordance with a preferred embodiment of the present invention, an electric motor 3 being coupled to a rear end of a housing 2. The housing 2 has a pump housing 7 defining a working fluid slot 5 and a rear end end joined to the electric motor 3, a vertical wall 4 is joined to the end of the Zhuopuwei body 7, a cylinder housing 8 is joined to the front end of the vertical wall 4 and defines a cylinder chamber, and a jaw 9 for holding a tool and forming the cylinder housing 8 so as to extend below the cylinder housing 8. A hydraulic pump 6 is placed in the pump housing 7. A piston 10 is axially slidably fitted into the cylinder housing 8. The cylinder chamber is divided by the piston 10 into a front working chamber 12, as viewed in the left side of Fig. 1, and a rear working chamber 13 as seen on the right side of Fig. 1. A piston rod 11 has a base portion joined to the piston 10, and a front portion that protrudes forward from the front end of the housing 2 through the cylinder housing 8.
該液壓幫浦6係一習知之型式，其包含譬如一藉著該 電動馬達3之軸桿3 a所驅動之凸輪機制1 4，以往復運動 一柱塞至加壓該工作流體槽5中所包含之工作流體。該殼 體2係設有一用以將已藉著該液壓幫浦6加壓之工作流體 餵入該後面工作室1 3之進給通道’及一用以將來自該前 面工作室1 2之工作流體回流進入該工作流體槽5之回流 通道。該進給通道係分成連接至該液壓幫浦6之第一進給 通道15及連接至該後面工作室13之第二進給通道16。 由該垂直壁面4之後表面及一支撐該電動馬達3之軸桿 3 a之軸承3 b所圍繞之小空間1 9係形成於該回流通道1 7 -8- (6) 1259112 及該工作流體槽5之間。 參考圖2，一軸向、設在底部之孔1 8係形成於該活 塞1 0及該活塞桿1 1之一後面部份中。一閥引導棒2 0由 該垂直壁面4突出進入該孔18 °該閥引導棒2 0係設有一 軸向導引孔2 1。該導引孔2 1延伸經過該閥引導棒2 0 ° 一 柱型放泄閥2 3係可軸向滑動地裝入該導引孔2 1。該柱型 放泄閥23具有一中空之閥桿24 ’及一固定至該閥桿24 前端之閥件2 5 ’以便安坐於一形成在該閥導引棒2 0前端 之閥座22上。設計該閥桿24之長度，以致該閥桿24由 該垂直壁面4突出向後進入該小空間1 9 °該閥桿2 4之一 後面部份具有一設有前面環狀溝槽2 6之前面溝槽式部份 及一設有後面環狀溝槽27之後面溝槽式部份。該前面環 狀溝槽2 6及該後面環狀溝槽2 7係隔開一段預定距離。該 前面環狀溝槽2 6連接該第一進給通道1 5及該第二進給通 道16或由該第二進給通道16分開該第一進給通道15， 且該背面環狀溝槽2 7連接該第一進給通道1 5及該回流通 道1 7或由該回流通道1 7分開該第一進給通道1 5，連接 該回流通道1 7及該小空間1 9或由該小空間1 9分開該回 流通道1 7。一台肩2 6 a延伸於該前面環狀溝槽2 6及該後 面環狀溝槽27之間。一台肩27a延伸在該後面環狀溝槽 2 7之後方。 於圖2所示狀態中，該第一進給通道1 5及第二進糸合 通道1 6之個別開放端點1 5 a及1 6 a與該前面溝槽式部份 之前面環狀溝槽2 6在同一位置，且該回流通道1 7藉著f亥 -9- (7) 1259112 後面溝槽式部份之後面環狀溝槽2 7與該小空間l 9相通。 於圖4所示狀態中，該第一進給通道1 5及該回流通道1 7 之個別開放端點1 5 a及1 7 a與該後面溝槽式部份之環狀溝 槽2 7在同一位置，且該閥桿2 4之台肩2 6 a由第一進給通 道15分開該第二進給通道16，及該閥桿24之台肩27a 由該小空間1 9分開該回流通道1 7。於圖3所示該閥桿24 係於圖2及4分別所示相同位置間之一中間位置之狀態中 ，該台肩2 6 a由該第二進給通道1 6分開該第一進給通道 1 5，且該第一進給通道1 5藉著該後面環狀溝槽2 7與該小 空間1 9相通。 該閥桿2 4突出進入該小空間1 9。一塞子2 9係於該 小空間1 9中附著至該閥桿2 4之後面端點部份。該中空閥 桿2 4之軸向孔具有一回流通道2 8之作用。一回復彈簧 3 〇係纏繞著該柱型放泄閥2 3之閥件2 5，以造成該閥件 25施行一放開作用。一彈簧31係置於該導引棒20及該 閥桿2 4間之一環狀空間中。該彈簧3 1具有與該環狀溝槽 之底部接觸之一端點及與該閥件2 5接觸之另一端點。 一回復彈簧3 2係置於該汽缸殼體8之前面工作室i 2 中，以便將該活塞1 〇向後推。一沖壓頭3 3係附著至該活 塞桿U之前端。該顎夾9固定一對應於該沖壓頭3 3而相 向於該沖壓頭3 3之鑄模3 4。 操作一把手3 5以連接該第二進給通道1 6至一回流通 道（未示出）’並連接至該工作流體槽5。當推進用於切 削加工之活塞桿1 1需要停止及回復至其原來位置時，操 -10- (8) 1259112 作該把手3 5。一彈性袋3 6基於該前面工作室i 2中之工 作流體之數量變化其形狀。 將敘述如此製成之複動型液壓致動器1之操作。該活 塞桿1 1及該柱型放泄閥2 3係在該複動型液壓致動器1開 始其操作之前保持在圖1及2所示位置；亦即該柱型放泄 閥2 ：>之閥件2 5係耢者該活塞桿1 1保持安坐在該閥座2 2 上。於此狀態中，該第一進給通道1 5及該第二進給通道 1 6之個別開放端點1 5 a及1 6 a與該前面環狀溝槽2 6在同 一位置，且因此連接該第一進給通道1 5及該第二進給通 道1 6。該後面環狀溝槽27之部份通入該小空間1 9，且該 後面環狀溝槽2 7之其餘部份對應於該回流通道1 7之開放 端點1 7 a，以連接該回流通道1 7至該小空間1 9。 然後，致動該電動馬達3以驅動該液壓幫浦6。因此 ’該工作流體槽5中所包含之工作流體係已加壓。該已加 壓之工作流體流動於該箭頭之方向中，並經過該第一進給 通道15及該開放端點15a進入該前面環狀溝槽26。該工 作流體進一步由該前面環狀溝槽2 6流動經過該第二進給 通道1 6進入該後面工作室丨3。因此，該活塞1 〇隨同該 活塞桿1 1向前推進’以於設置在該沖壓頭3 3及該鑄模 3 4間之一空間之鋼片等中沖壓孔。 以該已加壓之工作流體裝滿該活塞1 〇之孔1 8，而該 活基1 〇及該活塞桿1 1向前方移動。因此，該閥件2 5保 持女坐在該閥座2 2上’以將該柱型放泄閥2 3保持在圖1 及2所示位置。當該活塞丨〇及該活塞桿i丨進一步推進時 -11 - (9) 1259112 ，一附著至該活塞1 〇之後面端點之端板3 7與該回復彈簧 3 〇形成接觸，及壓縮該回復彈簧3 0。因此，該閥件2 5係 藉著該壓縮回復彈簧3 0之彈性由該閥座2 2分開。 然後，該閥桿24係藉著該彈簧3 1向前方移動，亦即 如圖1及2所視移至該左側，並至圖3所示之一自由位置 ，在此該閥桿24未遭受任何外在壓力。於該狀態中，該 第一進給通道之開放端點1 5 a通入該後面環狀溝槽2 7， 且該後面環狀溝槽2 7藉著該軸承3 b通入與該工作流體槽 5相通之小空間1 9。如此，流動經過該第一進給通道15 之工作流體流動於該箭頭之方向中及經過該後面環狀溝槽 2 7及該小空間1 9返回進入該工作流體槽5。該工作流體 由該後面工作室1 3經過該開放之回流通道2 8流動進入該 小空間1 9。因此，該活塞桿1 1停止推進。 當該液壓幫浦6在此狀態中連續地操作時，該已加壓 之工作流體流入該小空間1 9。既然該小空間1 9係藉著該 垂直壁面4及該軸承3 b所圍繞，該工作流體不可避免地 流動經過該滾珠及該軸承3 b之固定座間之間隙。然而， 該軸承3 b中之間隙係極小，該小空間1 9中之工作流體之 壓力上昇達一短時間。 於此一自由狀態中之柱型放泄閥23係進一步推進， 亦即如圖1及2所視移至該左側，並至圖4所示位置，在 此該台肩27a由該小空間19分開該後面環狀溝槽27。當 該閥桿24係移至圖4所示位置時，該工作流體由第一進 給通道1 5經過該後面環狀溝槽2 7流動進入該回流通道 -12 - (10) 1259112 1 7。然後，如圖5所示，該已加壓之工作流體流入該前面 工作室1 2。因此，該活塞1 〇係向後移動，亦即係如圖5 所視藉著該已加壓之工作流體移動至右側。如此，該活塞 1 〇藉著該工作流體之液壓壓力及該回復彈簧3 2之彈性兩 者確貫地向後移動。 當該活塞1 〇及該活塞桿1 1係如此回復至圖1所示其 原來位置時’該活塞桿1 1下壓該閥件2 5至將該閥件2 5 安坐在該閥座2 2上。因此，該柱型放泄閥2 3之閥桿2 4 係向後移動，該第一進給通道1 5之開放端點1 5 a係由該 後面環狀溝槽2 7分開，且該第一進給通道1 5藉著該前面 環狀溝槽2 6與該第二進給通道1 6相通。 於常態之切削加工中，該電動馬達3係於該沖壓頭 3 3穿過該鋼片時關掉，以停止將該已加壓之工作流體餵 入該後面工作室1 3。該回復彈簧3 2之彈性係高到足以爲 一回復沖程移動該活塞1 〇。當操作該把手3 5以在達成該 切削操作之前將該已加壓之工作流體送回進入該工作流體 槽5時，該閥件2 5係由該閥座2 2分開及該柱型放泄閥 2 3向前移動。因此，該加壓工作流體流入該前面工作室 1 2，以迫使該活塞1 〇回復至其原來位置。 如將由前面敘述變得明顯者，於根據本發明之複動型 液壓致動器中’該柱型放泄閥自動地控制該液壓電路，以 致該已加壓之工作流體流入該前面工作室，以迫使該活塞 桿回復至其原來位置及藉此該活塞桿能確實地回復至其原 來位置。 -13- (11) 1259112 既然該液壓電路係藉著優於由該柱型向放泄閥之運動 所造成該殻體中壓力平衡之變化作用所控制，不需要複雜 之電子零件。如此，該複動型液壓致動器係結構簡單，能 以低成本製成，及縱使施加震動仍將不會發生故障。 雖然具體化本發明之複動型液壓致動器已敘述爲應用 至一沖壓裝置，該複動型液壓致動器可應用至一使用切割 刃片之切割裝置及應用至一使用彎曲支臂之彎曲裝置。 雖然已在其較佳具體實施例中以某種獨特性程度敘述 本發明’在其中顯然可能有很多改變及變化。因此應瞭解 本發明可用異於在此所特別敘述之方式實現，而不會脫離 其範圍及精神。 【圖式簡單說明】 本發明之上面及其他目的、特色及優點將由以下關於 所附圖面所作之敘述變得更明顯，其中： 圖1係根據本發明一較佳具體實施例中之複動型液壓 致動器之一縱向剖視圖於中； 圖2係圖1所示複動型液壓致動器之基本部份之一放 大剖視圖； 圖3係一類似於圖2之放大剖視圖，其於緊接在回復 ί采作之則之一狀態中顯示一柱型放泄閥； 圖4係一類似於圖2之放大剖視圖，其於開始該回復 操作之一狀態中顯示一柱型放泄閥；及 圖5係一類似於圖丨之縱向剖視圖，其爲於開始該回 -14 - (12) 1259112 復操作之一狀態中之複動型液壓致動器。 主要元件對照表 1 :複動型液壓致動器 2 :殼體 3 :電動馬達 3 a :軸桿 3 b :軸承 鲁 4 :壁面 5 :工作流體槽 _ 6 :液壓幫浦 7 :幫浦殻體 8 :汽缸殼體 9 :顎夾 1 〇 :活塞 1 1 :活塞桿 ® 1 2 :前面工作室 1 3 :後面工作室 1 4 :凸輪機制 1 5 :第一進給通道 1 5 a :開放端點 1 6 :第二進給通道 1 6 a :開放端點 1 7 :回流通道 -15- (13) 1259112 1 7 a :開放端點 18 :孔 1 9 :空間 20 :閥引導棒 21 :導引孔 2 2 :閥座The hydraulic pump 6 is of a conventional type and includes a cam mechanism 14 driven by a shaft 3 a of the electric motor 3 to reciprocate a plunger to pressurize the working fluid tank 5 Contains the working fluid. The housing 2 is provided with a feeding passage for feeding the working fluid pressurized by the hydraulic pump 6 into the rear working chamber 13 and a working for the work from the front working chamber 1 2 The fluid flows back into the return passage of the working fluid tank 5. The feed passage is divided into a first feed passage 15 connected to the hydraulic pump 6 and a second feed passage 16 connected to the rear working chamber 13. A small space 19 surrounded by the rear surface of the vertical wall surface 4 and a bearing 3 b supporting the shaft 3 a of the electric motor 3 is formed in the return passage 1 7 -8- (6) 1259112 and the working fluid groove Between 5 Referring to Fig. 2, an axially disposed bottom hole 18 is formed in the piston 10 and a rear portion of the piston rod 11. A valve guiding rod 20 protrudes from the vertical wall surface 4 into the hole 18. The valve guiding rod 20 is provided with an axial guiding hole 21. The guide hole 2 1 extends through the valve guide rod 20 ° and the column type drain valve 2 3 is axially slidably fitted into the guide hole 21 . The column type bleed valve 23 has a hollow stem 24' and a valve member 25' fixed to the front end of the stem 24 for seating on a valve seat 22 formed at the front end of the valve guide rod 20. The length of the valve stem 24 is designed such that the valve stem 24 protrudes from the vertical wall surface 4 and enters the small space 1 9 °. The rear portion of the valve stem 24 has a front annular groove 26 The grooved portion and the grooved portion of the rear annular groove 27 are provided. The front annular groove 26 and the rear annular groove 27 are spaced apart by a predetermined distance. The front annular groove 26 is connected to the first feed channel 15 and the second feed channel 16 or the first feed channel 15 is separated by the second feed channel 16, and the back annular groove 2 7 connecting the first feed channel 15 and the return channel 17 or separating the first feed channel 15 from the return channel 17 , connecting the return channel 17 and the small space 1 9 or by the small The space 19 separates the return channel 17. A shoulder 26 6 a extends between the front annular groove 26 and the rear annular groove 27. A shoulder 27a extends behind the rear annular groove 2 7 . In the state shown in FIG. 2, the respective open end points 15a and 16a of the first feed channel 15 and the second feed channel 16 are opposite to the front grooved portion. The groove 26 is in the same position, and the return channel 17 communicates with the small space l 9 through the rear grooved groove 27 of the grooved portion of the rear surface of the hex-9-(7) 1259112. In the state shown in FIG. 4, the first infeed channel 15 and the individual open end points 1 5 a and 17 a of the return channel 17 and the annular groove 27 of the rear grooved portion are In the same position, the shoulder 26 6 a of the valve stem 24 is separated from the second feed passage 16 by the first feed passage 15 , and the shoulder 27 a of the valve stem 24 is separated by the small space 1 9 . 1 7. In the state shown in FIG. 3, the valve stem 24 is in an intermediate position between the same positions shown in FIGS. 2 and 4, the shoulder 26 6 a is separated from the first feed by the second feed passage 16 The channel 15 is connected to the small space 19 by the rear annular groove 27. The valve stem 24 protrudes into the small space 19. A plug 2 9 is attached to the end portion of the rear face of the valve stem 24 in the small space 19. The axial bore of the hollow valve stem 24 has a return passage 28. A return spring 3 is wound around the valve member 25 of the column type drain valve 23 to cause the valve member 25 to perform a release action. A spring 31 is placed in an annular space between the guide rod 20 and the valve stem 24. The spring 31 has one end that is in contact with the bottom of the annular groove and the other end that is in contact with the valve member 25. A return spring 32 is placed in the front face studio i 2 of the cylinder housing 8 to push the piston 1 backward. A stamping head 3 3 is attached to the front end of the piston rod U. The jaw 9 is fixed to a mold 34 corresponding to the stamping head 33 and facing the stamping head 33. A handle 3 5 is operated to connect the second feed passage 16 to a return passage (not shown) and is connected to the working fluid tank 5. When pushing the piston rod 1 1 for cutting to stop and return to its original position, operate -10- (8) 1259112 as the handle 35. An elastic bag 36 changes its shape based on the amount of working fluid in the front working chamber i 2 . The operation of the double-acting hydraulic actuator 1 thus produced will be described. The piston rod 1 1 and the column type bleed valve 23 are maintained at the positions shown in FIGS. 1 and 2 before the double-acting hydraulic actuator 1 starts its operation; that is, the column type bleed valve 2: The valve member 2 5 is used to hold the piston rod 1 1 seated on the valve seat 2 2 . In this state, the individual open ends 1 5 a and 16 a of the first feed channel 15 and the second feed channel 16 are in the same position as the front annular groove 26, and thus are connected. The first feed channel 15 and the second feed channel 16 are. A portion of the rear annular groove 27 opens into the small space 149, and the remaining portion of the rear annular groove 27 corresponds to the open end point 17a of the return channel 17 to connect the reflow. Channel 1 7 to the small space 1 9 . Then, the electric motor 3 is actuated to drive the hydraulic pump 6. Therefore, the working fluid system contained in the working fluid tank 5 has been pressurized. The pressurized working fluid flows in the direction of the arrow and enters the front annular groove 26 through the first feed passage 15 and the open end point 15a. The working fluid further flows from the front annular groove 26 through the second feed passage 16 into the rear working chamber 3. Therefore, the piston 1 向前 advances along with the piston rod 1 1 to punch a hole in a steel sheet or the like provided in a space between the punch head 33 and the mold 34. The pressurized working fluid fills the hole 1 of the piston 1 and the piston 1 and the piston rod 1 move forward. Therefore, the valve member 25 holds the female seat on the valve seat 22 to hold the column type bleed valve 2 3 in the position shown in Figs. When the piston rod and the piston rod i further advance, -11 - (9) 1259112, an end plate 37 attached to the end point of the piston 1 〇 is in contact with the return spring 3 ,, and compresses the Restore spring 3 0. Therefore, the valve member 25 is separated by the valve seat 22 by the elasticity of the compression return spring 30. Then, the valve stem 24 is moved forward by the spring 31, that is, as shown in FIGS. 1 and 2, to the left side, and to a free position shown in FIG. 3, where the valve stem 24 is not subjected to Any external pressure. In this state, the open end point 15 5 a of the first feed passage opens into the rear annular groove 27 , and the rear annular groove 27 7 opens into the working fluid through the bearing 3 b The small space through which the slot 5 communicates is 19. Thus, the working fluid flowing through the first feed passage 15 flows in the direction of the arrow and returns to the working fluid tank 5 through the rear annular groove 27 and the small space 19. The working fluid flows from the rear working chamber 13 through the open return passage 28 into the small space 19. Therefore, the piston rod 11 stops propulsion. When the hydraulic pump 6 is continuously operated in this state, the pressurized working fluid flows into the small space 19. Since the small space 19 is surrounded by the vertical wall 4 and the bearing 3 b, the working fluid inevitably flows through the gap between the ball and the fixed seat of the bearing 3 b . However, the gap in the bearing 3b is extremely small, and the pressure of the working fluid in the small space 19 rises for a short time. The column type bleed valve 23 in this free state is further advanced, i.e., moved to the left side as viewed in Figures 1 and 2, and to the position shown in Figure 4, where the shoulder 27a is from the small space 19 The rear annular groove 27 is separated. When the valve stem 24 is moved to the position shown in Figure 4, the working fluid flows from the first feed passage 15 through the rear annular groove 27 into the return passage -12 - (10) 1259112 17 . Then, as shown in Fig. 5, the pressurized working fluid flows into the front working chamber 12. Therefore, the piston 1 is moved backward, that is, as shown in Fig. 5, by the pressurized working fluid moving to the right side. Thus, the piston 1 确 is surely moved backward by the hydraulic pressure of the working fluid and the elasticity of the return spring 32. When the piston 1 〇 and the piston rod 11 are thus returned to their original positions as shown in FIG. 1 , the piston rod 1 1 presses the valve member 25 to seat the valve member 25 on the valve seat 2 2 on. Therefore, the valve stem 24 of the column type drain valve 23 moves backward, and the open end point 15 5 of the first feed channel 15 is separated by the rear annular groove 27, and the first The feed channel 15 communicates with the second feed channel 16 via the front annular groove 26. In the normal cutting process, the electric motor 3 is turned off when the punching head 3 passes through the steel sheet to stop feeding the pressurized working fluid to the rear working chamber 13. The spring of the return spring 32 is high enough to move the piston 1 为 for a return stroke. When the handle 35 is operated to return the pressurized working fluid back into the working fluid tank 5 before the cutting operation is reached, the valve member 25 is separated by the valve seat 22 and the column is discharged. Valve 2 3 moves forward. Therefore, the pressurized working fluid flows into the front working chamber 12 to force the piston 1 to return to its original position. As will be apparent from the foregoing description, in the double acting hydraulic actuator according to the present invention, the column type drain valve automatically controls the hydraulic circuit such that the pressurized working fluid flows into the front working chamber. To force the piston rod back to its original position and thereby the piston rod can be reliably returned to its original position. -13- (11) 1259112 Since the hydraulic circuit is controlled by a change in pressure balance in the housing caused by the movement of the column to the bleed valve, no complicated electronic parts are required. Thus, the double-acting hydraulic actuator has a simple structure, can be manufactured at low cost, and will not malfunction even if vibration is applied. Although the double acting hydraulic actuator embodying the present invention has been described as being applied to a punching device, the double acting hydraulic actuator can be applied to a cutting device using a cutting blade and applied to a curved arm. Bending device. Although the present invention has been described in terms of a certain degree of particularity in its preferred embodiments, it is obvious that many changes and modifications are possible. It is, therefore, to be understood that the invention may be BRIEF DESCRIPTION OF THE DRAWINGS The above and other objects, features and advantages of the present invention will become more apparent from 1 is a longitudinal cross-sectional view of a hydraulic actuator; FIG. 2 is an enlarged cross-sectional view showing an essential part of the double-acting hydraulic actuator shown in FIG. 1. FIG. 3 is an enlarged cross-sectional view similar to FIG. Figure 1 shows an enlarged cross-sectional view similar to Figure 2, showing a column-type bleed valve in a state in which the return operation is initiated; And Fig. 5 is a longitudinal cross-sectional view similar to the figure, which is a double acting hydraulic actuator in a state in which the return -14 - (12) 1259112 is repeated. Main components comparison table 1: Double acting hydraulic actuator 2: Housing 3: Electric motor 3 a: Shaft 3 b: Bearing Lu 4: Wall 5: Working fluid tank _ 6 : Hydraulic pump 7 : Pump housing Body 8: Cylinder housing 9: 颚 clamp 1 〇: Piston 1 1 : Piston rod® 1 2: Front working chamber 1 3: Rear working chamber 1 4 : Cam mechanism 1 5 : First feed channel 1 5 a : Open End point 1 6 : Second feed channel 1 6 a : Open end point 1 7 : Return channel -15- (13) 1259112 1 7 a : Open end point 18: Hole 1 9 : Space 20: Valve guide rod 21: Guide hole 2 2 : valve seat
2 3 :放泄閥 2 4 :閥桿 2 5 :閥件 2 6 :前面環狀溝槽 26a :台肩 2 7 :後面環狀溝槽 27a :台肩 2 8 :回流通道 2 9 :塞子2 3 : Drain valve 2 4 : Stem 2 5 : Valve member 2 6 : Front annular groove 26a : Shoulder 2 7 : Rear annular groove 27a : Shoulder 2 8 : Return channel 2 9 : Plug
3 0 :回流通道 3 1 :彈簧 3 2 :回復彈簧 3 3 :沖壓頭 3 4 :鑄模 3 5 :把手 3 6 :彈性袋 3 7 :端板 -16 -3 0 : return channel 3 1 : spring 3 2 : return spring 3 3 : punch head 3 4 : mold 3 5 : handle 3 6 : elastic bag 3 7 : end plate -16 -