200404678 (1) 玖、發明說明 【發明所屬之技術領域】 本發明是關於一種具有一延伸於缸中之螺桿的射出成 型設備，該缸具有一充塡開口及一噴嘴，螺桿連接一容納 於驅動外殻中的驅動軸，該驅動軸驅動連通於一第一及一 第二電驅動單元，驅動軸具有由第一驅動單元經由第一驅 動螺帽而嚙合的第一螺紋及螺距與第一螺紋的螺距不同之 第二螺紋，第二螺紋由第二驅動單元經由第二驅動螺帽而 嚙合，射出成型設備具有一控制器，其設置成爲用於調節 第一及第二驅動單元的轉動方向及轉動速率，俾使驅動軸 及螺桿在使用時能夠轉動及/或在軸向平移，而平移所需 的動力係由二驅動單元提供，且轉動所需的動力係由二驅 動單元提供。 本發明又關於一種使用此射出成型設備製造射出成型 產品之方法，其中第一及第二驅動單元的轉動方向及轉動 速率改變，俾使驅動軸及螺桿在使用時依據所欲的模式幸專 動及/或在軸向平移，而軸向平移所需的動力由二驅動單 元提供，且轉動所需的動力由二驅動單元提供。 【先前技術】 此射出成型設備自-例如-歐洲專利EP-A- 1 0 8 3 03 6 g EP-A-1 21 5 029 號而得知。 鑑於所需要的注入速率，用於軸向移動螺桿之最常用 的驅動係液壓驅動。然而，液壓驅動具有很多缺點，尤其 -5- (2) (2)200404678 是下列： -液壓驅動系統的勁性遠低於電驅動系統的勁性；. -在系統中，油的壓力脈動經常上升，其對於軸向定 位精確度不利； -液壓驅動遠比電驅動骯髒； -液壓驅動的靜態損失遠大於電驅動；且當螺桿空轉 時，必須提供液壓的壓力，其需要能量。 藉由完全由依據-例如-歐洲專利ΕΡ-Α-0 8 82 5 64號之 電馬達驅動的射出成型設備，這些問題已經解決。然而， 自該公告得知之電驅動射出成型設備具有很多缺點，尤其 是下列： -就軸向移動而言，總動力必須由一驅動單元提供， 所以，所關注的驅動單元必須具有可觀的動力； -就轉動移動而言，總動力必須由另一驅動單元提供 ，所以，所關注的驅動單元必須具有可觀的動力； -當軸向移動啓始時，必須促使用於所關注的移動之 驅動單元自靜止而轉動；此導致軸承之摩擦阻力的轉變（ 靜態摩擦阻力轉變爲動態摩擦阻力）及個別驅動單元的傳 動；此摩擦阻力的轉變使藉由馬達電流測量之精確的力量 回授變成不可能； •在驅動單元、驅動軸及驅動外殼之間有很多複雜的 力量傳動機構（Dl、D2、D3、E1)，其將轉動只轉換成爲 螺桿的軸向移動，或只轉換成爲轉動移動，或軸向及轉動 移動的組合；此傳動機構導致精確度的損失且更消耗動力 -6- (3) (3)200404678 •重馬達，及相關的傳動導致可觀的質量，其必須每次 引動；所以慣性質量高，因此，習知設備的動態行爲-特 別是控制速率-仍然係所欲者。 這些問題已由歐洲專利申請案EP-A- 1 083 03 6及歐 洲專利申請案EP-A· 1 2 1 5 029號的建議大致上解決。在 那些習知的射出成型機器中，驅動軸具有二段節距相反的 螺紋。各段由一驅動螺帽嚙合，該驅動螺帽各由一電馬達 互相獨立驅動。 然而，在這些公告中無一揭示以什麼方式驅動馬達， 即，根據什麼控制信號控制馬達。 【發明內容】 本發明之一目的是提供一種在開頭的段落中說明之型 式 的電射出成型設備，其設置成爲根據力回授的形式調 節射出成型操作的至少一部分。本發明之另一目的是提供 一種使用此射出成型設備之方法。 爲了該目的，在開頭的段落中說明之型式的電射出成 型設備之特徵爲依據本發明，驅動軸-至少用於待執行之 射出成型操作的一部分-在所欲的軸向力之施加下被驅動 ’而控制器（爲了根據力回授而調節之目的）測量當作輸入 信號之第一驅動單元所消耗的電流及第二驅動單元所消耗 的電流’控制器係設置成爲依據所欲的模式調節充塡壓力 -7- (4) (4)200404678 •開頭的第二段落中說明之型式的方法之特徵爲依據本 發明’驅動軸-至少用於待執'行之射出成型操作的一部分-在所欲的軸向力施加下被驅動，而控制器（爲了根據力回 授而e周節之目的）獲得當作輸入信號之第一驅動單元所消 耗的電流及第二驅動單元所消耗的電流，控制器係依據所 欲的模式調節充塡壓力。 藉由此設備與方法，軸向移動所需要的力是由二驅動 單兀提供。而且，用於轉動移動的力是由此二驅動單元提 供。當只需要螺桿的軸向位移而不需要轉動時，至少當驅 動軸上的第一與第二螺紋之節距相同且個別的型式相反-其係不需要的-時，二驅動單元在相反的方向以等速轉動 。當只需要螺桿的轉動時，二驅動單元在相同的方向以等 速轉動。螺桿之軸向位移與轉動的結合是藉由互相適當結 合二驅動單元的轉動方向與速率而獲得。二驅動單元之扭 矩的和提供輸出扭矩，且二驅動單元之扭矩的差經由傳動 至驅動軸而提供軸向力。 此也意指驅動的熱負載整體更佳地分佈於外殼上。因 此，很小的設計之簡單對流冷卻或水冷卻即已足夠。就依 據本發明的設備而言，由於與可用的動力相比，慣性質量 相當小，所以軸向位移-其特別在注入期間係以高速發生-可能快速發生，且耗費相當少的能量。此外，產生最小的 遲滯與加速力，以致於獲得用於產生注入力與塑化力之驅 動單元負載的良好控制。因爲在注入期間，驅動單元以相 -8- (5) - 200404678 反的方式轉動，至少當第一與第二螺紋的型式相反時，，二 馬達具有相反的反應扭矩。結果，幾乎不產生任何外部反 應扭矩，即使有也很少，以致於驅動外殼相對於外界的懸 承也可設計成爲相當輕。.另一額外的優點是可以使用相同 的驅動單元（其自維修的觀點而言是有利的）、儲存及成本 〇 根據馬達電流測量的力回授相當簡單，因爲在塑膠上 不需要有決定螺桿施加的力之感測器。附帶一提，本發明 φ 不排除補充此感測器以用於馬達電流測量。此外，馬達電 流實質上直接耦合至所施加的力，以致於使用最少的裝置 ，仍然可以獲得螺桿所施加的力之相當精確的指示。 在根據馬達電流測量的力回授中，重要的是在驅動單 元所需要的馬達電流與螺桿所提供的力之間的相當直接的 鏈接。即，驅動單元與螺桿之間所包括的傳動數目必須最 小。在依據本發明的射出成型設備中，驅動單元與驅動軸 之間僅有的傳動可能由一轉動螺帽形成，轉動螺帽固接於 鲁 個別驅動單元的轉子，且設在一徑向內表面上，用於與驅 動軸上的第一或第二螺紋合作。 依據本發明的又一構想，當驅動軸上的第一與第二螺 紋之節距足夠大，以致於螺桿心軸在使用時受到的軸向力 ~ 可以從第一與第二驅動單元所消耗的驅動單元電流精確地 - 導出，則特別有利。如果心軸與它的二螺帽並非自鎖式， 則此是可能的。另言之，摩擦力（靜態與動態）所導致的反 扭矩必須顯著小於心軸上的負載所導致的扭矩。 -9- (6) (6)200404678 依據本發明的又一構想，當節距角在3-30度的範圍 內，較佳爲約10度，，則獲得此效應。節距角是arctan(節 距/齒冠）。 ， 在塑化相，轉動方向是常數，且驅動單元連續轉動。 結果’在系統的靜態與動態摩擦阻力之間不發生轉換，所 以此轉換對於馬達電流控制的力回授中之磁滯沒有貢獻。 因此’且由於驅動軸的節距是大的，可以從二馬達的差異 電流很精確地導出塑化壓力，以便接著只調整二馬達的轉 動速率，到達適當的推進壓力，以用於塑化。 依據本發明的又一構想，控制器的設置是用於使射出 成型設備經歷塑化相、注入相及（選擇性）後壓力相。 在塑化相，螺桿轉動且在軸向移離噴嘴。當足夠的流 體塑膠可用時，接著是注入相，其中螺桿在噴嘴的方向快 速軸向移動。在注入相期間，缸的噴嘴所連接的鑄模被注 滿。然後，在塑膠於鑄模中硬化的期間，經歷了選擇性的 後壓力相。以此方式，於鑄模中硬化的期間導致的收縮獲 得補償，其方式爲如果需要的話，由於在噴嘴附近的缸中 維持一定的壓力，鑄模由塑膠塡補。 依據本發明的又一構想，塑化相與任何後壓力相中之 第一與第二驅動單元的控制是根據力回授，而注入相中之 第一與第二驅動單元的控制是根據位置回授。 在注入相期間，精確計量進入鑄模的特定體積是最重 要的。特別是當射出成型光碟與數位式影音光碟時，其並 非使用完全封閉的鑄模，因此，充塡壓力並非鑄模是否完 -10- (7) (7)200404678 全充塡的計量，此位置控制的注入相有大的優點。附帶一 提，可想到其他產品，其涉及以部分開啓的鑄模工作，待 計量的體積因而特別重要。另一方面，在塑化相與後壓力 相的期間，在流體塑膠上維持特殊的壓力是重要的。由於 該控制結合二控制原理，乃獲得一射出成型設備，其具有 前述的全部相中之所欲的調節行爲。 驅動單元可各包含一伺服馬達，各具有它本身的馬達 控制器，而中央控制器設置成爲用於產生相同型式的控制 量値，且使這些控制量値傳送至伺服馬達的馬達控制器。 控制量値可以是-例如-位置、速率或加速度。現代的伺服 馬達裝有馬達角度編碼器，該馬達角度編碼器可用於在-例如-注入相期間之螺桿的位置控制、速率控制及/或加速 度控制。伺服馬達與驅動軸之間的特殊直接傳動及使用馬 達角度編碼器的結果，仍然獲得很高解析度之軸向位置控 制、速率控制及/或加速度控制。此外，藉由此伺服馬達 ，可使用標準高性能伺服控制器，其具有優良的調節行爲 ，而實際上防止發生調節的偏差。 較佳地，由中央控制器傳送的控制量値在注入相的某 些相中是根據馬達電流測量而決定，在其他相中是根據缸 中之螺桿之所欲的位置、速率或加速度而決定。 因爲在各狀況的馬達控制器根據相同的控制量-諸如 ，位置、速率、加速度及/或急衝-接收控制信號，所以在 馬達控制器中不需要有控制調節開關，其改進馬達之運動 輪廓的穩定性。有時候，自一種輸入信號轉變至另一種輸 -11 - (8) (8)200404678 入信號-例如，自力輸入信號轉變至位置輸入信號-導致個 別馬達之短暫未界定的運動行爲。該問題由依據上述其他 構想的變形解決。 · 爲了獲得精巧的射出成型設備，較佳者爲，第一與第 二驅動單元設置成爲共軸。此外，在注入相的期間，如果 二螺桿的型式相反，則二馬達產生的外部扭矩互相抵消， 以致於所得的外部扭矩是零。 爲了能夠自射出鑄模移走缸的噴嘴，依據本發明的又 一構想，驅動外殻安裝在一滑動件上，滑動件具有一較佳 爲電動的驅動器，用於在軸向移動驅動外殼及與它連接的 缸。 爲了補助根據馬達電流測量的力回授，射出成型設備 可以具有力感測器’諸如壓電元件或應變計’其測量螺桿 施加的力，力感測器連接至用於力回授的控制器’該控制 器設置成爲依據所欲的模式調節充塡壓力。 注意DE-A-3 9 3 8 3 5 3號揭示一種心軸驅動器，其具 有二馬達，馬達經由傳動器個別嚙合一心軸的左旋式及右 旋式螺紋。在此公告中特別提到的可能用途是處理裝備、 機器人、握爪，且所示的示範性實施例顯示具有一配接 器-其中可以承接一工具-的實施例。 本發明的其他構想在申請專利範圍依附項中說明，此 後將參考圖進一步解釋。 【實施方式】 -12- 200404678 Ο) 圖式中所示的示範性實施例顯示具有一螺桿2 ·其在 缸中延伸-的射出成型設備1。缸3具有一用於引入塑膠 粒的充塡開口 4及一可連接至射出鑄模的噴嘴5。經由噴 嘴5，塑膠-那時候是流體-被壓出缸3而至鑄模中。螺桿 2連接一容納於驅動外殼6中的驅動軸7。驅動軸7個別 驅動連通於第一及第二電驅動單元8及9。驅動軸7具有 由第一驅動單兀8經由第一驅動螺帽1 1嚙合的左旋式螺 紋1 0及由第二驅動單元9經由第二驅動螺帽1 3嚙合的右 旋式螺紋1 2。驅動螺帽可以簡單地具有內螺紋，但是也 可以設計成爲習知的球型轉動螺帽。此外，示意顯示一控 制器1 4 ’其設置成爲用於個別調節第一及第二驅動單元8 及9的轉動方向與轉動速率，俾使驅動軸7與螺桿2可以 操作性轉動及在軸向平移。軸向平移所需要的動力是由二 驅動單元8、9提供。轉動所需要的動力也是由二驅動單 元8、9提供。 在本示範性實施例中，第一與第二電驅動單元8、9 個別直接驅動第一與第二螺帽1 1、1 3，其個別嚙合驅動 軸7的左旋式與右旋式螺紋1 0、1 2。爲了該目的，螺帽 1 1、1 3直接連接於驅動螺帽8、9的轉子8 b、9 b。 驅動外殼6安裝在不意指示的滑動件1 6上，其具有 一較佳爲電動的驅動器1 7，用於在軸向移動驅動外殻6 及與彼連接的缸3。於是，噴嘴5可以移動離開及朝向一 射出鑄模。 爲了在製造期間使螺桿2與驅動軸7保持可以操縱， -13· (10) (10)200404678 這些零件在本示範性實施例中設計成爲鬆散的零件，其由 耦合器· 1 8互聯。耦合器1 8構建成爲破裂耦合器。此提供 的優點是減少螺桿2損壞的機會。這是因爲當由驅動軸7 施加在螺桿上的力變成過高時，破裂耦合器1 8破裂且不 再施力於螺桿2及/或驅動軸7。注意，本發明也包含一驅 動軸7與螺桿2，其設計成爲單件、整合式部件。 在極特殊的狀況，可能由於控制器中的干擾，驅動軸 在軸向非所欲地高速移動。此可能使射出成型設備受損。 爲了防止此狀況，所示的示範性實施例具有一軸向制動器 1 9，其設在驅動軸7上，且其在控制誤差導致驅動軸7發 生非所欲的軸向位移時開始操作。所示的制動器1 9具有 一裝在驅動軸7上的球2 0，其可相對於軸7移動於驅動 軸7的軸向衝程之所允許的長度。移動性受限於二止動件 21、22。球20容納於一套筒23中，其固接於驅動外殼6 。球2 0只可在套筒2 3塑性變形的狀況下於套筒2 3中移 動。於是，實現可靠的制動路徑，其足夠短，以防止碰撞 所致的損壞及伴隨而來的遲滯力。 在本示範性實施例中，控制器1 4設置成爲使射出成 型設備1經歷一塑化相、一注入相及一後壓力相。在塑化 相時，藉由轉動螺桿1 2，同時使它緩慢移離噴嘴5，提供 足夠的流體予一部分塑膠。當所需數量的流體塑膠可用時 ，藉由在噴嘴5的方向高速移動螺桿2，注入相的流體經 由噴嘴5迅速注入鑄模。當鑄模由所欲體積的流體塑膠充 塡時，接著是後壓力相，其中鑄模內的流體塑膠保持受壓 -14- (11) - 200404678 ’以致於發生在鑄模中的收縮由.後充塡補償。爲了該目的 ’在本示範性實施例中，塑化相與後壓力相之第一及第二 驅動單元8、9的控制器1 4是根據力回授。在注入相，第 一及第二驅動單元8、9的控制器1 4是根據位置回授。 爲了根據力回授而調節，控制器獲得當作輸入信號之 第一驅動單元8消耗的電流及第二驅動單元消耗的電流。 根據馬達電流測量，控制器1 4可以計算所欲的控制量値 ’例如，所欲的速率、所欲的位置及/或所欲的加速度， φ 且傳送這些所欲的控制量値至至驅動單元8、9-較佳爲設 計成爲伺服馬達-的馬達控制器，於是依據所欲的模式調 節充塡壓力。 爲了補助，射出成型設備1可以具有至少一力感測器 1 5，諸如壓電元件或很多應變計，其測量螺桿2施加的力 。力感測器1 5連接至用於力回授的控制器1 4。控制器1 4 設置成爲依據其所欲的模式調節充塡壓力 在本示範性實施例中，驅動單元8、9各設計成爲伺 _ 服馬達8、9，該伺服馬達設置成爲共軸。伺服馬達各具 有一靜子8a、9a及一轉子8b、9b。如已指示於上者，轉 子8 b、9 b個別固接於一稍早提到的螺帽1 1、1 3。控制器 1 4設置成爲用於伺服馬達8、9的位置控制驅動。如已指 ' 示於上者，控制器1 4又設置成爲用於伺服馬達8、9的力 ' 控制驅動。 較佳地，驅動軸7上的左旋式與右旋式螺紋1 0、1 2 之節距足夠大，以致於螺桿2在使用時受到的軸向力可以 -15- (12) (12)200404678 從第一與第二驅動單元8與9所消耗的驅動單元電流精確 地導出。爲了該目的，在此示範性實施例中，節距角在 3 - 3 0度的範圍內。較佳地，節距角是約1 〇度’ 在注入相期間，其中待供應至模穴的流體塑膠之數量 特別重要，控制器14(並非使用力回授）可以只指定所欲的 控制量値-例如，所欲的位置、所欲的速率、所欲的加速 度及/或所欲的急衝-至馬達控制器，以致於在該相，所涉 及的是電馬達8、9之純粹的位置控制、速率控制、角速 度控制及/或急衝控制。 在根據力回授或馬達電流回授而控制的相及在根據控 制量値-例如，位置-而控制的射出成型操作的相二者之期 間，馬達控制器的輸入由相同型式之每次的控制量組成， 所達成的優點爲，自一輸入信號切換至另一輸入信號的結 果不會產生馬達控制器的控制不規則性。這是因爲在整個 射出成型操作，馬達控制器每次從中央控制器接收相同控 制量的値。 顯然，本發明不限於所說明的示範性實施例，而在申 請專利範圍所界定之本發明的範疇內之各種修改是可行的 〇 例如’在一循環內的全部相可以只根據位置回授而實 現，以致於不僅在注入相，而且在塑化相與後壓力相，螺 桿的移動是位置控制。在那些狀況，馬達電流測量只經由 系統的內部核對而執行。此外，可以使用相同型式而不同 節距角的第一與第二螺紋，以取代左旋與右旋式螺紋。而 -16- (13) (13)200404678 且，當使用左旋與右旋式螺紋時，那些螺紋的節距角不需 要相同。 【圖式簡單說明】 圖1顯示依據本發明的射出成型設備之示範性實施例 的驅動單元側視圖； 圖2顯示在圖1之線π · Π所作的剖面。 圖式代表符號說明 1 射出成型設備 2 螺桿 3 缸 4 充塡開口 5 噴嘴 6 驅動外殼 7 驅動軸 8 第一驅動單元 8 a 靜子 8b 轉子 9 第二電驅動單元 9 a 靜子 9b 轉子 10 左旋式螺紋 11 第一驅動螺帽 -17, 200404678 (14) 12 右旋式螺紋 13 第二驅動螺帽 14 控制器 15 力感測器 16 滑動件 17 驅動器 18 耦合器 19 制動器 20 球 2 1 止動件 22 止動件 23 套筒200404678 (1) Description of the invention [Technical field to which the invention belongs] The present invention relates to an injection molding device having a screw extending in a cylinder, the cylinder having a filling opening and a nozzle, and the screw is connected to be accommodated in a drive A drive shaft in the housing, the drive shaft drivingly communicates with a first and a second electric drive unit, and the drive shaft has a first thread and a pitch and a first thread engaged by the first drive unit through the first drive nut. A second thread with a different pitch, the second thread is engaged by the second drive unit via the second drive nut, and the injection molding device has a controller that is configured to adjust the rotation directions of the first and second drive units and The rotation speed enables the driving shaft and the screw to rotate and / or translate in the axial direction when in use, and the power system required for translation is provided by the two driving units, and the power system required for rotation is provided by the two driving units. The present invention also relates to a method for manufacturing an injection molded product using the injection molding device, wherein the rotation direction and the rotation rate of the first and second driving units are changed, so that the driving shaft and the screw are moved according to a desired mode when in use. And / or translation in the axial direction, and the power required for the axial translation is provided by the two driving units, and the power required for rotation is provided by the two driving units. [Prior Art] This injection molding equipment is known from, for example, European Patent EP-A-1 0 8 3 03 6 g EP-A-1 21 5 029. Given the required injection rate, the most commonly used drive for axially moving the screw is a hydraulic drive. However, the hydraulic drive has many disadvantages, especially -5- (2) (2) 200404678 is the following:-the stiffness of the hydraulic drive system is much lower than that of the electric drive system;-in the system, the pressure pulsation of the oil is often Ascending, it is not good for axial positioning accuracy;-Hydraulic drive is much dirty than electric drive;-Static loss of hydraulic drive is much greater than electric drive; and when the screw is idling, hydraulic pressure must be provided, which requires energy. These problems have been solved by injection molding equipment driven entirely by electric motors based on, for example, European Patent EP-A-0 8 82 5 64. However, the electric drive injection molding equipment learned from this announcement has many disadvantages, especially the following:-In terms of axial movement, the total power must be provided by a drive unit, so the drive unit of interest must have considerable power; -For rotational movement, the total power must be provided by another drive unit, so the drive unit of interest must have considerable power;-When the axial movement starts, the drive unit for the movement of interest must be promoted Rotates from standstill; this results in a change in the frictional resistance of the bearing (static frictional resistance into dynamic frictional resistance) and the transmission of individual drive units; this transition in frictional resistance makes it impossible to accurately feedback the force by motor current measurement ; • There are many complicated force transmission mechanisms (Dl, D2, D3, E1) between the drive unit, the drive shaft and the drive housing, which convert the rotation only into the axial movement of the screw, or only the rotation movement, or A combination of axial and rotational movement; this transmission mechanism results in a loss of accuracy and consumes more power -6- (3) (3) 200404678 • Heavy motors and related transmissions cause considerable mass, which must be triggered each time; therefore, the mass of inertia is high, so the dynamic behavior of known devices-especially the rate control-is still what one wants. These problems have been largely solved by the proposals of European patent application EP-A-1 083 03 6 and European patent application EP-A · 1 2 1 5 029. In those conventional injection molding machines, the drive shaft has two threads with opposite pitches. Each segment is engaged by a drive nut which is driven independently of each other by an electric motor. However, none of these publications discloses how the motor is driven, that is, what control signal is used to control the motor. SUMMARY OF THE INVENTION An object of the present invention is to provide an electric injection molding apparatus of the type described in the opening paragraph, which is arranged to adjust at least a part of the injection molding operation according to the form of force feedback. Another object of the present invention is to provide a method using the injection molding apparatus. For this purpose, the features of the electric injection molding device of the type described in the opening paragraph are that according to the invention, the drive shaft-at least part of the injection molding operation to be performed-is driven under the application of the desired axial force. Drive 'and the controller (for the purpose of adjusting based on force feedback) measures the current consumed by the first drive unit and the current consumed by the second drive unit as input signals. The controller is set to the desired mode Adjusting the filling pressure -7- (4) (4) 200404678 • The method of the type described in the second paragraph at the beginning is characterized by the drive shaft according to the invention-at least part of the injection molding operation performed- It is driven under the application of the desired axial force, and the controller (for the purpose of e-cycle according to the force feedback) obtains the current consumed by the first drive unit as the input signal and the current consumed by the second drive unit. Current, the controller adjusts the filling pressure according to the desired mode. With this device and method, the force required for axial movement is provided by the two driving units. Moreover, the force for the rotational movement is provided by the two driving units. When only the axial displacement of the screw is required without rotation, at least when the pitch of the first and second threads on the drive shaft is the same and the individual types are opposite-which is not required-the two drive units are in opposite directions The direction turns at a constant speed. When only the rotation of the screw is required, the two drive units rotate at the same speed in the same direction. The combination of the axial displacement and rotation of the screw is obtained by appropriately combining the rotation direction and speed of the two drive units with each other. The sum of the torques of the two drive units provides output torque, and the difference between the torques of the two drive units is transmitted to the drive shaft to provide axial force. This also means that the thermal load of the drive is better distributed throughout the housing. Therefore, simple convection or water cooling for small designs is sufficient. As far as the device according to the invention is concerned, since the mass of inertia is relatively small compared to the available power, axial displacements-which occur at high speeds especially during the injection-can occur quickly and consume relatively little energy. In addition, minimal hysteresis and acceleration force are generated, so that a good control of the load of the driving unit for generating injection force and plasticizing force is obtained. Because during the injection, the drive unit rotates in the opposite direction of phase -8- (5)-200404678, at least when the first and second thread patterns are reversed, the two motors have opposite reaction torques. As a result, almost no external reaction torque is generated, and even if there is very little, the suspension of the drive housing with respect to the outside can be designed to be quite light. Another additional advantage is that the same drive unit (which is advantageous from a self-maintenance point of view), storage, and cost can be used. Force feedback based on motor current measurement is fairly simple, because there is no need for a decision screw on the plastic. Sensor of applied force. Incidentally, the invention φ does not exclude supplementing this sensor for motor current measurement. In addition, the motor current is essentially directly coupled to the applied force so that the least amount of equipment is used and a fairly accurate indication of the force applied by the screw can still be obtained. In force feedback based on motor current measurement, it is important to have a fairly direct link between the motor current required by the drive unit and the force provided by the screw. That is, the number of transmissions included between the drive unit and the screw must be minimized. In the injection molding equipment according to the present invention, the only transmission between the driving unit and the driving shaft may be formed by a rotating nut, which is fixed to the rotor of the individual driving unit and is provided on a radially inner surface For cooperation with the first or second thread on the drive shaft. According to another concept of the present invention, when the pitch of the first and second threads on the drive shaft is large enough, the axial force received by the screw mandrel in use can be consumed by the first and second drive units. The drive unit current is precisely-derived, which is particularly advantageous. This is possible if the mandrel and its two nuts are not self-locking. In other words, the reaction torque caused by friction (static and dynamic) must be significantly smaller than the torque caused by the load on the mandrel. -9- (6) (6) 200404678 According to another concept of the present invention, this effect is obtained when the pitch angle is in the range of 3-30 degrees, preferably about 10 degrees. The pitch angle is arctan (pitch / crown). In the plasticizing phase, the rotation direction is constant, and the driving unit continuously rotates. As a result, there is no transition between the static and dynamic friction resistance of the system, so the transition does not contribute to the hysteresis in the force feedback of the motor current control. Therefore, and because the pitch of the driving shaft is large, the plasticizing pressure can be accurately derived from the difference current of the two motors, so that only the rotation speed of the two motors can be adjusted to reach an appropriate propulsive pressure for plasticizing. According to another concept of the present invention, the controller is configured to subject the injection molding device to a plasticizing phase, an injection phase, and a (selective) post-pressure phase. During the plasticizing phase, the screw rotates and moves away from the nozzle in the axial direction. When sufficient fluid plastic is available, the injection phase is followed, where the screw moves rapidly axially in the direction of the nozzle. During the injection phase, the mold to which the nozzle of the cylinder is connected is filled. Then, as the plastic hardens in the mold, it undergoes a selective post-pressure phase. In this way, the shrinkage caused during the hardening period in the mold is compensated by maintaining the pressure in the cylinder near the nozzle if necessary, and the mold is made up of plastic. According to another concept of the present invention, the control of the first and second driving units in the plasticizing phase and any post-pressure phase is based on force feedback, and the control of the first and second driving units in the injection phase is based on position Feedback. During the injection phase, it is most important to accurately meter the specific volume entering the mold. In particular, when molding discs and digital audio-visual discs are ejected, they do not use completely closed molds. Therefore, the filling pressure is not a measure of whether the molds are complete. -10- (7) (7) 200404678 Full filling measurement The injection phase has great advantages. Incidentally, other products are conceivable, which involve working with a partially opened mold, and the volume to be metered is therefore particularly important. On the other hand, it is important to maintain a special pressure on the fluid plastic during the plasticizing phase and the post-pressure phase. Since this control is combined with the two control principles, an injection molding device is obtained, which has the desired adjustment behavior in all the aforementioned phases. The drive units may each include a servo motor, each having its own motor controller, and the central controller is configured to generate the same type of control variables, and transmit these control variables to the motor controller of the servo motor. The control volume can be-for example-position, velocity or acceleration. Modern servo motors are equipped with a motor angle encoder which can be used for position control, rate control and / or acceleration control of the screw during, for example, the injection phase. As a result of the special direct drive between the servo motor and the drive shaft and the use of a motor angle encoder, high resolution axial position control, rate control and / or acceleration control are still obtained. In addition, with this servo motor, a standard high-performance servo controller can be used, which has excellent adjustment behavior while actually preventing adjustment deviations. Preferably, the control amount 传送 transmitted by the central controller is determined in some phases of the injection phase according to the measurement of the motor current, in other phases it is determined according to the desired position, velocity or acceleration of the screw in the cylinder . Because the motor controller in each situation receives control signals based on the same control amount-such as position, velocity, acceleration, and / or rush-there is no need for a control adjustment switch in the motor controller, which improves the motor's motion profile The stability. Sometimes, the transition from one input signal to another input-(8) (8) 200404678 input signal-for example, the transition from a self-powered input signal to a position input signal-results in a transient undefined motion behavior of an individual motor. This problem is solved by a variant based on the other ideas described above. In order to obtain a compact injection molding apparatus, it is preferable that the first and second driving units are disposed coaxially. In addition, during the injection phase, if the types of the two screws are opposite, the external torques generated by the two motors cancel each other, so that the obtained external torque is zero. In order to be able to remove the nozzle of the cylinder from the injection mold, according to another concept of the present invention, the driving housing is mounted on a sliding member, and the sliding member has a preferably electric driver for moving the driving housing in the axial direction and with It connects the cylinder. To supplement the force feedback measured according to the motor current, the injection molding device may have a force sensor 'such as a piezoelectric element or a strain gauge' which measures the force applied by the screw, and the force sensor is connected to a controller for force feedback 'The controller is set to adjust the filling pressure according to the desired mode. Note that DE-A-3 No. 9 3 8 3 5 3 discloses a mandrel drive having two motors, and the motors individually engage the left-handed and right-handed threads of a mandrel through the actuator. Possible uses specifically mentioned in this bulletin are processing equipment, robots, grippers, and the exemplary embodiment shown shows an embodiment with an adapter in which a tool can be received. Other concepts of the present invention are described in the appended claims, and will be explained further with reference to the drawings. [Embodiment] -12- 200404678 0) The exemplary embodiment shown in the drawing shows an injection molding apparatus 1 having a screw 2-which extends in a cylinder. The cylinder 3 has a filling opening 4 for introducing plastic pellets and a nozzle 5 connectable to an injection mold. Via the nozzle 5, the plastic, which was then a fluid, is pressed out of the cylinder 3 into the mold. The screw 2 is connected to a drive shaft 7 housed in a drive housing 6. The drive shaft 7 is individually connected to the first and second electric drive units 8 and 9. The drive shaft 7 has a left-handed thread 10 engaged by the first drive unit 8 via the first drive nut 11 and a right-handed thread 12 engaged by the second drive unit 9 via the second drive nut 13. The driving nut may simply have internal threads, but it may also be designed as a conventional ball-type rotating nut. In addition, a controller 1 4 ′ is shown schematically for setting the rotation direction and rotation rate of the first and second drive units 8 and 9 individually, so that the drive shaft 7 and the screw 2 can be operatively rotated and axially adjusted. Pan. The power required for axial translation is provided by the two drive units 8,9. The power required for rotation is also provided by the two drive units 8,9. In the present exemplary embodiment, the first and second electric drive units 8 and 9 directly drive the first and second nut 1 1 and 1 3 respectively, and each of them individually engages the left-handed and right-handed threads 1 of the drive shaft 7. 0, 1 2. For this purpose, the nuts 11, 1 3 are directly connected to the rotors 8 b, 9 b which drive the nuts 8, 9. The drive housing 6 is mounted on an unintentional slide 16 and has a preferably electric drive 17 for moving the drive housing 6 and the cylinder 3 connected to it in the axial direction. Thus, the nozzle 5 can be moved away from and directed toward an injection mold. In order to keep the screw 2 and the drive shaft 7 maneuverable during manufacturing, these parts are designed as loose parts in this exemplary embodiment, which are interconnected by a coupler 18. The coupler 18 is constructed as a rupture coupler. This provides the advantage of reducing the chance of screw 2 damage. This is because when the force applied to the screw by the drive shaft 7 becomes too high, the rupture coupler 18 is broken and no more force is applied to the screw 2 and / or the drive shaft 7. Note that the present invention also includes a drive shaft 7 and a screw 2, which are designed as a single piece, an integrated part. In extremely special situations, the drive shaft may move undesirably at high speed in the axial direction due to interference in the controller. This may damage the injection molding equipment. To prevent this, the exemplary embodiment shown has an axial brake 19 provided on the drive shaft 7, and it starts operating when a control error causes an undesired axial displacement of the drive shaft 7. The brake 19 shown has a ball 20 mounted on the drive shaft 7, which is movable relative to the shaft 7 by a permissible length of the axial stroke of the drive shaft 7. Mobility is limited by the two stops 21,22. The ball 20 is housed in a sleeve 23 which is fixed to the drive housing 6. The ball 20 can be moved in the sleeve 23 only when the sleeve 23 is plastically deformed. As a result, a reliable braking path is achieved, which is short enough to prevent damage caused by a collision and the attendant hysteresis. In the present exemplary embodiment, the controller 14 is arranged to subject the injection molding apparatus 1 to a plasticizing phase, an injection phase, and a post-pressure phase. During the plasticizing phase, by turning the screw 12 while moving it slowly away from the nozzle 5, sufficient fluid is provided to a portion of the plastic. When the required amount of fluid plastic is available, by moving the screw 2 at high speed in the direction of the nozzle 5, the fluid in the injection phase is quickly injected into the mold through the nozzle 5. When the mold is filled with the desired volume of fluid plastic, followed by the post-pressure phase, where the fluid plastic in the mold remains under pressure -14- (11)-200404678 'so that the shrinkage that occurs in the mold is caused by the post-filling make up. For this purpose, in the present exemplary embodiment, the controllers 14 of the first and second driving units 8, 9 of the plasticizing phase and the post-pressure phase are feedback based on force. In the injection phase, the controllers 14 of the first and second drive units 8, 9 are feedback based on the position. In order to adjust according to the force feedback, the controller obtains the current consumed by the first drive unit 8 and the current consumed by the second drive unit as input signals. Based on the motor current measurement, the controller 14 can calculate the desired control amounts 値 ', for example, the desired speed, the desired position, and / or the desired acceleration, φ and transmit these desired control amounts to the drive The units 8, 9-are preferably motor controllers designed as servo motors, so that the filling pressure is adjusted according to the desired mode. To assist, the injection molding apparatus 1 may have at least one force sensor 15 such as a piezoelectric element or many strain gauges that measure the force applied by the screw 2. The force sensor 15 is connected to a controller 14 for force feedback. The controller 1 4 is set to adjust the filling pressure according to a desired mode. In this exemplary embodiment, the drive units 8 and 9 are each designed as a servo motor 8 and 9, and the servo motors are set to be coaxial. The servo motors each have a stator 8a, 9a and a rotor 8b, 9b. If indicated above, rotors 8 b and 9 b are individually fixed to a nut 1 1, 1 3 mentioned earlier. The controller 14 is provided as a position control drive for the servo motors 8 and 9. As already indicated 'shown above, the controller 14 is again set as a force for the servo motors 8, 9' to control the drive. Preferably, the pitch of the left-handed and right-handed threads 10, 12 on the drive shaft 7 is large enough that the axial force that the screw 2 receives during use can be -15- (12) (12) 200404678 The drive unit currents consumed by the first and second drive units 8 and 9 are accurately derived. For this purpose, in this exemplary embodiment, the pitch angle is in the range of 3-30 degrees. Preferably, the pitch angle is about 10 degrees. During the injection phase, the quantity of fluid plastic to be supplied to the cavity is particularly important. The controller 14 (not using force feedback) can only specify the desired control amount値 —for example, the desired position, the desired speed, the desired acceleration, and / or the desired rush—to the motor controller, so that in this phase, the electric motors 8, 9 are purely Position control, rate control, angular velocity control and / or rush control. During both the phase controlled according to the force feedback or the motor current feedback and the phase of the injection molding operation controlled based on the control amount 例如-for example, the position-the input of the motor controller is The control quantity composition has the advantage that the result of switching from one input signal to another input signal does not generate control irregularities of the motor controller. This is because during the entire injection molding operation, the motor controller receives the same amount of plutonium from the central controller each time. Obviously, the present invention is not limited to the illustrated exemplary embodiments, but various modifications are possible within the scope of the present invention as defined by the scope of the patent application. For example, 'all phases in a cycle can be based on position feedback only. Realized so that not only in the injection phase, but also in the plasticizing phase and the post-pressure phase, the movement of the screw is position controlled. In those cases, motor current measurements are performed only through internal checks of the system. In addition, the first and second threads of the same type and different pitch angles may be used instead of the left-handed and right-handed threads. And -16- (13) (13) 200404678, and when using left-handed and right-handed threads, the pitch angles of those threads need not be the same. [Brief Description of the Drawings] Fig. 1 shows a side view of a drive unit of an exemplary embodiment of an injection molding apparatus according to the present invention; Description of Symbols of Drawings 1 Injection molding equipment 2 Screw 3 Cylinder 4 Filling opening 5 Nozzle 6 Drive housing 7 Drive shaft 8 First drive unit 8 a Static element 8b Rotor 9 Second electrical drive unit 9 a Static element 9b Rotor 10 Left-handed thread 11 First drive nut-17, 200404678 (14) 12 Right-handed thread 13 Second drive nut 14 Controller 15 Force sensor 16 Slider 17 Drive 18 Coupler 19 Brake 20 Ball 2 1 Stopper 22 Stop 23 sleeve
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