200400108 玖、發明說明 【發明所屬之技術領域】 本發明係關於一種伺服壓機之馬達過載保護方法，在 藉伺服馬達透過既定動力傳輸機構來驅動滑件之伺服壓機 ，防止壓機自動運轉中之滑件驅動用伺服馬達之過載異常 〇 【先前技術】 藉伺服馬達，透過滾珠螺桿、肘節連桿機構、曲柄機 構或偏心機構等既定動力傳輸機構來往復驅動滑件之伺服 壓機，可藉由伺服控制伺服馬達之位置及速度，來控制滑 件使其成爲適於工件加工條件之滑件運動，而具有卓越優 點。並且由於利用此優點，可高精密成形加工，又可謀求 衝程（stroke)數增加所帶來的生產性提高，故近年來開始廣 爲使用（例如，參考日本特許文獻1、日本特許文獻2)。 於上述之伺服壓機中，在以自動運轉模式連續進行工 件加工時，伺服馬達之溫度會因伺服馬達之連續變化之負 載電流而徐徐上昇。亦即，相當於伺服馬達有效輸出轉矩 之工作量的能量會導致伺服馬達發熱。通常，伺服馬達之 最大容許輸出電流受到其周圍溫度以及馬達本身之溫度限 制，因此，馬達本身之溫度一超過既定最大容許溫度，即 藉其伺服放大器之熱監視功能，輸出過載異常之警告信號 ，俾對伺服馬達作熱方面的保護。此時，一輸入此過載異 常信號，即切斷對伺服馬達之指令，亦切斷主電路電源對 伺服放大器之輸入，俾切斷電流對伺服馬達之輸出。 200400108 曰本特許文獻1 曰本特開平10 - 277797號公報 日本特許文獻2 曰本特願2002— 175831號 不過，由於在上述習知伺服壓機中，一旦於壓機連續 運轉時發生馬達過載異常，即如前述，伺服放大器切斷馬 達電流輸出，同時，此主電路電源亦斷開，因此，爲了解 除伺服放大器之此種過載異常停止，需要在暫時切斷伺服 放大器之控制電源之後，等待馬達溫度降到既定値以下， 再度接通控制電源及主電路電源之操作。因此，若出現暫 時過載異常警報，再起動壓機運轉需耗費時間，致自動運 轉之生產性降低。 又，於自動運轉中因突然過載異常而伺服馬達停止情 形下，若正在工件加工中，即不僅會製出不良加工品，且 爲了再起動，需要自滑件停止狀態上昇滑件，退回待機點 ，自模具排出不良加工品，此後再起動之煩瑣操作，並且 亦有費時之問題。 【發明內容】 本發明著眼於上述問題，其目的在於提供一種伺服壓 機之馬達過載保護方法，即使於壓機自動運轉中亦可防止 伺服馬達過載異常發生。 爲了達成上述目的，第1發明爲一種伺服壓機之馬達 過載保護方法，該伺服機壓係藉伺服馬達，透過既定動力 傳輸機構驅動滑件者；檢測伺服馬達作動時之負載電流， 200400108 於自動運轉中，根據包含所檢出馬達負載電流之過去實測 値求出熱量累計値，當所求得熱量累計値超過第1熱量累 計閩値時，暫時將滑件停止於成形領域以外之既定位置。 根據第1發明，由於監視大致與馬達溫度成正比之馬 達熱量累計値，此馬達熱量累計値一達到第1熱量累計閾 値即暫時停止滑件，於過載異常發生之前降低馬達溫度， 故可防患自動運轉中之過載異常之發生於未然。因此，無 過載異常發生造成之長時間運轉中斷或再起動用操作，可 提高生產性及作業性。此外，亦不會製出不良加工品。 又，上述成形領域係指滑件對工件加壓進行成形或將 模墊下壓之滑件動作領域。 第2發明爲一種伺服壓機之馬達過載保護方法，該伺 服機壓係藉伺服馬達，透過既定動力傳輸機構驅動滑件者 ;檢測伺服馬達作動時之負載電流，於自動運轉中，根據 包含所檢出馬達負載電流之過去實測値求出熱量累計値， 當所求得熱量累計値超過第1熱量累計閾値時，暫時停止 滑件，此後，當所檢出目前馬達負載電流高於既定値時， 將滑件上昇既定距離，暫時停止。 根據第2發明，由於監視大致與馬達溫度成比例之馬 達熱量累計値，其一達到既定之第1熱量累計閾値，即暫 時停止滑件，此後，於目前馬達負載電流値在既定値以上 時，亦即於伺服馬達在發生既定値以上之加壓轉矩狀態下 停止時，爲了減小馬達負載，將滑件上昇既定距離，暫時 停止，故可在出現過載異常之前，將馬達負載電流降至既 200400108 定値以下。由於藉此降低馬達溫度，故可防患自動運轉中 之過載異常發生於未然。因此，消除過載異常發生所造成 之長時間運轉中斷或用來再起動之操作，可提高生產性及 作業性。此外，不會製出不良加工品。 第3發明之方法係於第1或第2發明中，在前述滑件 暫時停止後，再度檢測馬達負載電流，當根據包含此時檢 出之馬達負載電流之過去實測値求得之熱量累計値一低於 第2熱量累計閾値時，即解除前述滑件之暫時停止，而成 爲再起動狀態。 根據第3發明，由於當馬達熱量累計値一低於第2熱 量累計閾値時，即解除暫時停止，而成爲再起動狀態，亦 即於連續運轉模式時，再開始運轉，或例如於外部安全一 行程模式時，設成轉移進料裝置對壓機要求起動之等待狀 態，故可繼續自動運轉。藉此，可一面監視馬達溫度，避 免馬達過載異常，一面自動運轉。又，於待機點暫時停止 時，可容易再開始與轉移進料器等同步之運轉。 第4發明之方法係於第1或第2發明中，於前述滑件 暫時停止後，當歷經既定時間時，即解除前述滑件之暫時 停止而成爲再起動狀態。 根據第4發明，由於暫時停止後，當歷經既定時間（ 馬達溫度降低既定量所需之預先設定時間）時，即成爲再 起動狀態（如同前述），故可繼續自動運轉。藉此，可一 面監視馬達溫度，避馬達過載異常，一面自動運轉。又， 於待機點暫時停止時，可容易再開始與轉移進料器等同步 200400108 之運轉。 【實施方式】 以下參考圖式詳細說明本發明之實施形態。 首先，根據圖1、圖2說明適用本發明之伺服壓機之構 造。圖1及圖2分別係伺服壓機之側面局部截面圖及背面 局部截面圖。 衝壓機械1係伺服壓機（下稱伺服壓機1)，藉伺服馬 達21驅動滑件3。滑件3上下移動自如地支承於伺服壓機 1之本體機架2之大致中央部，於與滑件3對向之下部配設 安裝於底座4上之承梁5。模具閉合高度調整用螺軸7之本 體部以成防止鬆脫狀態轉動自如地***形成於滑件3上部 之孔內。螺軸7之螺釘部7a向上從滑件3露出，與設於螺 軸7上方之柱塞11下部之母螺紋部螺合。 蝸輪裝置8之蝸輪8a安裝於螺軸7之本體部外周，與 此蝸輪8a螺合之蝸輪裝置8之蝸桿8b透過齒輪9a連結於 安裝在滑件3背面部之感應馬達9之輸出軸。感應馬達9 軸向長度短而成扁平狀，且配置成小型。 前述柱塞11之上部藉銷11a轉動自如地與第1連桿 12a之一端部連結，於此第1連桿12a之另一端與一端部轉 動自如地連結於本體機架2之第2連桿12b之另一端部之 間，設於三軸連桿13 —側之二連結孔藉銷14a、14b轉動自 如地連結。三軸連桿13另一側之連結孔轉動自如地連結於 後述之滑件驅動邰20之偏心軸28。第1連桿12a、第2連 桿12b以及三軸連桿13構成肘節連桿機構。 200400108 滑件驅動用伺服馬達21以軸心朝壓機左右方向安裝於 本體機架2之側面部，皮帶23 (通常由確動皮帶構成）捲 裝在安裝於該伺服馬達21輸出軸之第1滑輪22a與安裝在 軸心朝向壓機左右方向轉動自如地設於伺服馬達21上方之 中間軸24之第2滑輪22b之間。又，驅動軸27轉動自如 地支承於中間軸24上方之本體機架2上，安裝於驅動軸27 一端側之齒輪26與安裝於中間軸24之齒輪25嚙合。並且 ，偏心軸28形成於驅動軸27之軸心方向大致中央部，前 述三軸連桿13之另一側轉動自如地連結於此偏心軸28外 周部之偏心位置。 與前述螺軸7之下端面部之間密閉之油室6形成於滑 件3內，此油室6透過形成於滑件3內之油路6a連接於切 換閥16。切換閥16係切換操作油對油室6內部的供給、排 放。通過切換閥16供至油室6內之操作油在衝壓加工時間 閉塞於油室6內，透過油室6內之油將加壓時之推壓力傳 輸至滑件3。若過載施加於滑件3，油室6內之油壓超過既 定値，油即自未圖示之保險閥回流至油槽，滑件3緩衝既 定量，使滑件3及模具不致於損壞。 又，自上下二處向本體機架2側面部突出之1對托架 31、31安裝於滑架3之背面部，位置檢測桿32安裝於上下 1對托架31、31之間。線性標尺（linear scale)等之位置感測 器33之本體部，上下移動自如地嵌插於設有位置檢測用刻 度部之位置檢測桿32。位置感測器33固定於設在本體機架 2側面部之輔助架34上。此輔助架34形成沿上下方向縱向 200400108 伸長，下部藉螺栓35安裝於本體機架2側面部，上部藉插 入未圖示之上下方向長孔內之螺栓36沿上下方向滑動自如 地支持，側部藉前後1對支持構件37、37抵接、支持。 由於輔助架34作成僅上下任一側（於本例中爲下側） 固定於本體機架2，另一側上下移動自如地被支持之構造， 故不會受到本體機架2因溫度變化而發生之伸縮影響。藉 此，前述位置感測器33不會受到本體機架2因溫度變化而 發生之伸縮影響，可正確檢測滑件位置及模具閉合高度（die height) 〇 其次，根據圖3所示控制構造方塊圖說明控制裝置之 硬體構造。 本控制裝置之控制器10具備：記憶體l〇a、監視顯示 器19、電流感測器29、位置感測器33、伺服放大器45以 及滑件驅動用伺服馬達21。 電流感測器29檢測伺服馬達21之負載電流，將此檢 出之電流値輸出至控制器10。 又，前述位置感測器33將所檢出之滑件位置輸出至控 制器10。 記憶體10a記憶預先設定之滑件運動資料以及表示滑 件位置與伺服馬達21之旋轉角度之關係之表資料。而且， 此關係由前述偏心軸28之偏心長度、前述肘節連桿機構之 各連桿長度、偏心軸28之旋轉中心位置與肘節連桿之關係 等決定。 又，監視顯示器19根據來自控制器10之顯示指令， 12 200400108 顯示滑件目前位置（高度）、此時之馬達負載電流値以及 馬達負載狀態之運算値等各種監視資訊、警告信息等。此 顯示器可由LED (發光二極體）等數字顯示器、液晶等文 字顯示器或圖形顯示器等構成。 並且，控制器10由電腦裝置或PLL (可程式邏輯控制 器，即所謂的可程式定序器）等高速運算裝置構成。此控 制器10參考記憶於前述記憶體l〇a之滑件位置/馬達旋轉 角度對應表，根據預先設定之動作資料定出控制用之滑件 動作，在爲連續運轉模式時，進行運算處理，俾滑件按照 此定出之動作移動，根據目標位置與自位置感測器33輸入 之位置之偏差値，求出伺服馬達21之速度指令，將其輸出 至伺服放大器45。又，在微動模式或安全一行程模式時， 爲了使滑件僅在未圖示之操作按鈕開關之操作中（不過， 於安全一行程模式中，一超過下死點，即儘管進行操作鈕 操作，亦連續上昇至上死點而停止）以一定速度移動，根 據目標値與自位置感測器33輸入之位置間之偏差値求出伺 服馬達21之速度指令，輸出至伺服放大器45。 進一步，在如上述驅動伺服馬達21之期間內，控制器 10自電流感測器29輸出驅動中伺服馬達21之負載電流値 ，根據此負載狀態，在達到過載狀態之前，上昇伺服馬達 21達既定距離，減輕負載，藉此防患馬達過載異常之發生 於未然。進一步監視目前之滑件位置、伺服馬達電流値、 過載狀態等各種資訊，將顯示指令輸出至監視顯示器19。 將來自未圖示之伺服馬達旋轉角度感測器之馬達旋轉 13 200400108 角度反饋至伺服放大器45。伺服放大器45運算來自控制器 10之速度指令與自此馬達旋轉角度求得之速度反饋信號間 之偏差値，根據所求得偏差値控制伺服馬達21以減小該偏 差値。藉此，高精度控制滑件之位置及速度。 其次，根據圖4所示控制流程圖，一面參考圖5，一面 說明本發明馬達過載保護方法之第1實施形態之處理順序 。圖5是第1實施形態之馬達過載保護方法之滑件位置、 馬達產生轉矩、熱量累計値之時間圖表。 於圖4中，首先在步驟si將第1熱量累計閾値Qsl及 第2熱量累計閾値Qs2設定爲既定値。如圖5所示，此第1 熱量累計閾値Qsl是供檢查爲達到本馬達過載保護所進行 暫時停止控制之時序之閾値，其設定成小於伺服馬達21所 具有耐熱容量閾値Qm，亦即小於對應過載異常之最大容許 熱量累計値達既定量（相當於充裕度）之値。又，第2熱 量累計閩値Qs2是供檢查解除暫時停止再起動之時序之閾 値，馬達溫度對應於僅低於暫時停止時之溫度達既定溫度 時之溫度。而且，雖然可設定成第1熱量累計閾値Qsl^第 2熱量累計閾値Qs2之關係，不過，爲了穩定控制暫時停止 及再起動，較佳地，第1熱量累計閾値（^1>第2熱量累計 閾値Qs2，俾具有溫度監視之滯後現象。並且，初始化（淸 除）供以下運算處理使用之實電流値表II至In。於此，η 是以下運算所求得熱量累計値Qn可等效表示馬達溫度程度 之大小之資料數。 其次，於步驟s2檢測伺服馬達21動作中之電流値In 14 200400108 ，將其記憶於實測電流値表Π至In，進一步於步驟3藉算 式「Qn= Σ in · kn」運算熱量累計値Qn。於此，kn ( n= 1 至η)爲對應於自測定時刻起歷經時間加權以減小其作用程 度之係數，其中0 $ kn - 1 S kn。此後，於步驟s4，依「In 一 1 —In」推移實測電流値表II至In之資料，結果，消除 最舊的過去實測値11之資料。並且，其次於步驟s5檢查此 求得之熱量累計値Qn是否在第1熱量累計閾値Qsl以上， 於其不在第熱量累計閾値Qsl以上時，回到步驟s2，重複 進行以上處理。 於上述步驟s5，在其高於第1熱量累計閩値Qsl時， 進至步驟s6,暫時將滑件停止於成形領域以外之既定位置 (例如預先設定之待機點或上死點等），同時顯示「暫時 停止中」等警告信息於監視顯示器19。而且，亦可用聲音 通知「暫時停止中」。此後，於步驟s7檢測伺服馬達21 之電流値In，將其記憶於前述實測電流値表II至In，其次 ，於步驟s8，藉與前式相同之算式「Qn=EIn· Kn」運算 熱量累計値Qn，進一步於步驟s9，如「In - 1 —In」位移實 測電流値表II至In之資料，進至步驟slO，檢查此新求得 之熱量累計値Qn是否在第2熱量累計値Qs2以下。於其不 在第2熱量累計閾値Qs2以下時，回到步驟s7，重複進行 以上處理，在其低於第2熱量累計閾値Qs2時，於步驟si 1 解除暫時停止，成再起動滑件之狀態，其次回到步驟s2， 重複進行處理。 此外，步驟sll之滑件再起動狀態於例如自動運轉之 15 200400108 連續運轉模式情形下係再開始連續運轉狀態，又，在與轉 移壓機等之轉移進料器同步運轉之外部安全一行程模式情 形下，若係有來自轉移進料裝置之壓機起動要求信號即可 起動之起動要求等待狀態等。 其次，藉圖5說明上述方法之作動。 於圖5中，在時刻t0，於連續運轉模式下操作運轉鈕 ，連續起動壓機。由於控制器10控制伺服馬達21之位置 及速度，使滑件按照預先設定之滑件運動模式移動，故負 載電流以對應於上述滑件運動之型式流至伺服馬達21。隨 著對應於滑件1同運轉（周時間Tc)之負載電流於每1周 繼續流動，伺服馬達21之溫度逐漸上昇。控制器1〇測定 這段期間之馬達電流値In，根據至此時爲止之馬達電流値 In之實測資料，藉算式「Qn = Σ In · Kn」運算熱量累計値 Q7(其大致與馬達溫度上昇成比例）（步驟s2、s3)。並 且，檢查於連續運轉中此次求出之熱量累計値Qn是否在既 定第1熱量累計閾値Qsl以上（步驟s5)，於其不在第1 熱量累計閾値Qsl以上時，在達到第1熱量累計閾値QS1 之則繼I買上述之處理。且於熱量累計値Qn之運算時，過去 之電流實測値藉加權係數kn，對應歷經時間，減小其對溫 度上昇之作用程度（步驟S4)。 並且，於時刻t2，此次所求得之熱量累計値Qn在第1 熱量累計閾値Qsl以上時，在目前運轉中之週期結束之後 ’於時刻t3，暫時停止滑件於成形領域以外之既定位置（ 步驟s6)。藉此，將伺服馬達21之負載電流減少爲位置保 16 200400108 持所需之小電流，實現熱量累計値Qn之減少，亦即，急遽 降低伺服馬達21及伺服放大器內之電源電路之大電力半導 體元件之溫度。此後，繼續監視馬達電流値In，根據就每 一既定運算處理週期時間所檢出馬達電流値In以及過去之 馬達電流之實測値資料求出熱量累計値Qn (步驟S7、8、9 )，在此求得之最新熱量累計値Qn低於第二熱量累計閾値 Qs2之前，繼續暫時停止（步驟slO)。並且，若此熱量累 計値Qn低於第2熱量累計閾値Qs2 (圖5之時刻t4)，即 將滑件設成再起動狀態（步驟sll)。 此外，上述實施形態固然說明適用於藉伺服馬達21旋 轉偏心軸28，藉此旋轉動力，透過肘節連桿機構驅動滑件 3之構造之伺服壓機例，不過，本發明不限於此，例如可藉 伺服壓機直接驅動螺桿螺帽，藉此直接驅動力直接驅動滑 件之直接驅動型伺服壓機，或者，亦可適用於藉伺服馬達 ，透過連桿機構或偏心機構等偏心旋轉驅動部以及連桿昇 降驅動滑件之伺服壓機，或藉螺桿螺帽推拉驅動肘節連桿 機構之伺服壓機。 又，實施形態固然監視根據馬達負載電流値之實測資 料’藉由運算求得之熱量累計値之大小，不過，亦可替代 熱量累計値，而監視馬達溫度。 又，就解除暫時停止再起動之條件而言，不限於如上 述判斷馬達溫度（熱量累計値）是否在既定第2熱量累計 閾値Qs2以下之方法，例如在盡可能僅降低馬達溫度（熱量 累5十値）達既疋量之時間經過之後再起動亦無妨。 17 200400108 其次，藉圖6、7說明第2實施形態。且第2實施形態 之控制構造與圖3所示者相同。 首先，藉圖6說明第2實施形態之處理順序。圖6係 第2實施形態之控制流程圖，對同圖中與圖4相同處理內 容之步驟標示相同步驟號碼，省略說明。 於步驟si至步驟S5以與第1實施形態相同之順序進行 處理。於步驟s5檢查前述求得之熱量累計値Qn是否在第1 量累計閾値Qsl以上，在其高於第1熱量累計値Qsl時， 於步驟s21，在此情形下（即使加壓加工中）暫時停止。其 次，於步驟s22檢測伺服馬達21停止中之電流値Is，並且 於步驟s23檢查此電流値Is是否在既定容許値Ir以上，在 小於容許値Ir時，轉至步驟s6，繼續目前滑件3之暫時停 止位置。於上述步驟s23在電流値15高於既定容許値Ir時 ，於步驟s24朝馬達負載減小方向驅動伺服馬達21既定量 ，亦即，自此時之停止位置上昇滑件3達既定距離。此後 ，於前述步驟s6暫時停止滑件3，爾後，進行前述步驟S7 至步驟sll之處理。 接著，參考圖7說明第2實施形態之作動。如同第1 實施形態，若在時刻to之後以連續運轉模式運轉壓機，負 載電流即以對應滑件動作之型式流至伺服馬達21。隨此， 伺服馬達21之溫度逐漸上昇。於此期間內，控制器1〇測 定馬達電流値In，根據截至目前爲止馬達電流値In之實測 資料，藉算式「Qn= ΣΙη · Kn」運算熱量累計値Qn (步驟 s2、s3)。並且，於連續運轉中檢測此次求得之熱量累計値 200400108200400108 发明 Description of the invention [Technical field to which the invention belongs] The present invention relates to a motor overload protection method for a servo press. By using a servo motor to drive a servo press of a slider through a predetermined power transmission mechanism, the press is prevented from automatically running. Overload abnormality of the servo motor for slide drive. [Prior technology] The servo press for reciprocatingly driving the slide by the servo motor through a predetermined power transmission mechanism such as a ball screw, toggle link mechanism, crank mechanism or eccentric mechanism. By controlling the position and speed of the servo motor to control the slider to make it suitable for the workpiece processing conditions, the slider has excellent advantages. In addition, since this advantage can be used, high-precision molding can be performed, and productivity can be improved by increasing the number of strokes. Therefore, it has been widely used in recent years (for example, refer to Japanese Patent Document 1, Japanese Patent Document 2) . In the above-mentioned servo press, when the workpiece is continuously processed in the automatic operation mode, the temperature of the servo motor will gradually increase due to the continuously changing load current of the servo motor. That is, the energy equivalent to the workload of the effective output torque of the servo motor will cause the servo motor to generate heat. In general, the maximum allowable output current of a servo motor is limited by its surrounding temperature and the temperature of the motor itself. Therefore, once the temperature of the motor exceeds a predetermined maximum allowable temperature, it will use its thermal monitoring function of the servo amplifier to output an overload warning signal.热 Protect the servo motor from heat. At this time, as soon as this overload abnormal signal is input, the command to the servo motor is cut off, the input of the main circuit power to the servo amplifier is cut off, and the output of the current to the servo motor is cut off. 200400108 Japanese Patent Document 1 Japanese Patent Application Publication No. 10-277797 Japanese Patent Document 2 Japanese Patent Application No. 2002-175831 However, in the conventional servo press described above, an abnormal motor overload occurs when the press is continuously operated. That is, as mentioned above, the servo amplifier cuts off the motor current output, and at the same time, the main circuit power supply is also disconnected. Therefore, in order to release the overload stop of the servo amplifier, it is necessary to wait for the motor after temporarily cutting off the control power of the servo amplifier. When the temperature drops below the predetermined temperature, turn on the control power and the main circuit power again. Therefore, if there is a temporary overload abnormal alarm, it will take time to restart the press, which will reduce the productivity of automatic operation. In addition, when the servo motor is stopped due to a sudden overload abnormality during automatic operation, if a workpiece is being processed, not only will a defective machined product be produced, but in order to restart, it is necessary to raise the slider from the stopped state of the slider and return to the standby point. The troublesome operation of discharging the badly processed products from the mold and restarting it afterwards is also a time-consuming problem. SUMMARY OF THE INVENTION The present invention focuses on the above problems, and an object thereof is to provide a motor overload protection method for a servo press, which can prevent the servo motor from being overloaded even during the automatic operation of the press. In order to achieve the above object, the first invention is a motor overload protection method for a servo press, which uses a servo motor to drive a slider through a predetermined power transmission mechanism; detects the load current when the servo motor operates, 200400108 in automatic During operation, the heat accumulation is calculated based on the past actual measurement including the detected motor load current. When the calculated heat accumulation exceeds the first heat accumulation, the slider is temporarily stopped at a predetermined position outside the forming area. According to the first invention, the motor heat accumulation, which is approximately proportional to the temperature of the motor, is monitored. When the motor heat accumulation reaches the first heat accumulation threshold, the slider is temporarily stopped, and the motor temperature is lowered before an overload abnormality occurs. An overload abnormality in automatic operation occurs beforehand. Therefore, there is no long-term operation interruption or restart operation caused by an overload abnormality, which improves productivity and workability. In addition, defective processed products are not produced. The above-mentioned forming field refers to an operating field of a slider in which a slider presses a workpiece to form a shape or presses a die pad. The second invention is a motor overload protection method for a servo press. The servo press uses a servo motor to drive a slider through a predetermined power transmission mechanism; detects the load current when the servo motor operates, and automatically operates according to Detect the past actual measurement of the motor load current and find the heat accumulation. When the calculated heat accumulation exceeds the first heat accumulation threshold, stop the slider temporarily. After that, when the detected current load current of the motor is higher than the predetermined value, , Raise the slider a predetermined distance and stop temporarily. According to the second invention, since the motor heat accumulation 値, which is approximately proportional to the motor temperature, is monitored, once it reaches a predetermined first heat accumulation threshold 値, the slider is temporarily stopped, and thereafter, when the current motor load current 値 is above the predetermined ，, That is, when the servo motor is stopped under a state of pressure torque above the predetermined threshold, in order to reduce the motor load, the slider is raised by a predetermined distance and temporarily stopped. Therefore, before the overload abnormality occurs, the motor load current can be reduced to Both 200400108 fixed below. As a result, the temperature of the motor is reduced, so that an overload abnormality during automatic operation can be prevented before it happens. Therefore, eliminating long-term operation interruptions or restarting operations caused by overload abnormalities can improve productivity and workability. In addition, no defective processed products are produced. The method of the third invention is in the first or second invention. After the aforementioned slider is temporarily stopped, the motor load current is detected again, and the accumulated heat is calculated based on the past actual measurement including the motor load current detected at this time. As soon as it is lower than the second heat accumulation threshold 値, the temporary stop of the slider is released, and a restart state is obtained. According to the third invention, when the motor heat accumulation amount is lower than the second heat accumulation threshold value, the temporary stop is canceled, and the state is restarted, that is, when the continuous operation mode is started, the operation is restarted or, for example, when the external safety In the stroke mode, it is set to the waiting state of the transfer feeding device for the press to start, so it can continue to run automatically. This allows the motor to run automatically while monitoring the motor temperature to avoid abnormal motor overload. When the stand-by point is temporarily stopped, it is easy to restart the synchronized operation with the transfer feeder or the like. The method of the fourth invention is the first or second invention. After the slider is temporarily stopped, when the predetermined time elapses, the temporary stop of the slider is canceled and the restart state is obtained. According to the fourth aspect of the present invention, since a predetermined time (a predetermined time required for the motor temperature to decrease by a predetermined amount) elapses after a temporary stop, the motor is restarted (as described above), and thus the automatic operation can be continued. With this, the motor can be automatically operated while monitoring the temperature of the motor to avoid abnormal motor overload. In addition, when the stand-by point is temporarily stopped, it is easy to resume the operation of 200400108 in synchronization with the transfer feeder and the like. [Embodiment] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. First, the structure of a servo press to which the present invention is applied will be described with reference to Figs. 1 and 2. Figures 1 and 2 are a partial cross-sectional view of the side and a partial cross-sectional view of the back of the servo press, respectively. The stamping machine 1 is a servo press (hereinafter referred to as the servo press 1). The servo motor 21 is used to drive the slider 3. The slider 3 is supported on the substantially central portion of the main body frame 2 of the servo press 1 so as to move up and down, and a bearing beam 5 mounted on the base 4 is arranged at a lower portion opposite to the slider 3. The main body of the screw closing height adjustment screw shaft 7 is inserted into a hole formed in the upper part of the slider 3 in a rotatable manner so as to prevent loosening. The screw portion 7a of the screw shaft 7 is exposed upward from the slider 3, and is screwed with the female screw portion of the plunger 11 provided above the screw shaft 7. The worm gear 8a of the worm gear device 8 is mounted on the outer periphery of the main body portion of the screw shaft 7, and the worm 8b of the worm gear device 8 screwed with the worm gear 8a is connected to the output shaft of the induction motor 9 mounted on the back portion of the slider 3 through a gear 9a. The induction motor 9 has a short axial length, is flat, and is arranged in a small size. The upper borrow pin 11a of the plunger 11 is rotatably connected to one end of the first link 12a, and the other end of the first link 12a and one end are rotatably connected to the second link of the main body frame 2. Between the other ends of 12b, the two connecting holes 14a, 14b provided on the side of the triaxial link 13 are freely connected. The connecting hole on the other side of the three-axis link 13 is rotatably connected to an eccentric shaft 28 of a slider driving roller 20 to be described later. The first link 12a, the second link 12b, and the triaxial link 13 constitute a toggle link mechanism. 200400108 The servo motor 21 for slide drive is mounted on the side of the main body frame 2 with the shaft centered in the left-right direction of the press. The belt 23 (usually composed of a moving belt) is wound on the first mounted on the output shaft of the servo motor 21 The pulley 22a and the second pulley 22b of the intermediate shaft 24 which is rotatably provided above the servo motor 21 with the shaft center facing the left-right direction of the press. The drive shaft 27 is rotatably supported on the main body frame 2 above the intermediate shaft 24, and a gear 26 mounted on one end side of the drive shaft 27 is engaged with a gear 25 mounted on the intermediate shaft 24. The eccentric shaft 28 is formed at a substantially central portion in the axial direction of the drive shaft 27, and the other side of the aforementioned three-axis link 13 is rotatably connected to the eccentric position of the outer peripheral portion of the eccentric shaft 28. An oil chamber 6 sealed from the lower end surface of the screw shaft 7 is formed in the slider 3, and the oil chamber 6 is connected to the switching valve 16 through an oil passage 6a formed in the slider 3. The switching valve 16 switches the supply and discharge of the operating oil into the oil chamber 6. The operating oil supplied to the oil chamber 6 through the switching valve 16 is closed in the oil chamber 6 during the press working time, and the pressure during pressurization is transmitted to the slider 3 through the oil in the oil chamber 6. If an overload is applied to the sliding member 3 and the oil pressure in the oil chamber 6 exceeds a predetermined pressure, the oil will return to the oil tank from a safety valve (not shown), and the sliding member 3 cushions the predetermined amount, so that the sliding member 3 and the mold will not be damaged. A pair of brackets 31 and 31 protruding from the upper and lower positions toward the side of the main body frame 2 are mounted on the rear surface of the carriage 3, and the position detection lever 32 is mounted between the pair of upper and lower brackets 31 and 31. The body part of the position sensor 33 such as a linear scale is freely moved up and down and is inserted into a position detection lever 32 provided with a position detection scale. The position sensor 33 is fixed to an auxiliary frame 34 provided on a side portion of the main body frame 2. This auxiliary frame 34 is elongated in the vertical direction 400400108. The lower part is mounted on the side of the main body frame 2 by bolts 35. The upper part is supported by the bolts 36 inserted into the long holes (not shown) in the upper and lower directions and slidably supported in the vertical direction. A pair of support members 37 and 37 are abutted and supported by the front and back. Since the auxiliary frame 34 is fixed to the main body frame 2 on only one side (the lower side in this example), and the other side is supported to move freely up and down, it is not affected by the main body frame 2 due to temperature changes. Scaling effects that occur. Thereby, the aforementioned position sensor 33 is not affected by the expansion and contraction of the main body frame 2 due to temperature changes, and can correctly detect the position of the slider and the die height. Secondly, control the construction block according to FIG. 3 The figure illustrates the hardware structure of the control device. The controller 10 of the control device includes a memory 10a, a monitor display 19, a current sensor 29, a position sensor 33, a servo amplifier 45, and a servo motor 21 for slider driving. The current sensor 29 detects the load current of the servo motor 21 and outputs the detected current 値 to the controller 10. The position sensor 33 outputs the detected position of the slider to the controller 10. The memory 10a stores preset slider movement data and table data indicating the relationship between the slider position and the rotation angle of the servo motor 21. The relationship is determined by the eccentric length of the eccentric shaft 28, the length of each link of the toggle link mechanism, the relationship between the position of the rotation center of the eccentric shaft 28, and the toggle link. In addition, the monitoring display 19 displays various monitoring information and warning information such as the current position (height) of the slider, the current motor load current, and the calculation of the motor load status based on the display instruction from the controller 10. The display can be composed of a digital display such as an LED (light emitting diode), a text display such as a liquid crystal display, or a graphic display. The controller 10 is constituted by a computer device or a high-speed computing device such as a PLL (programmable logic controller, so-called programmable sequencer). This controller 10 refers to the slider position / motor rotation angle correspondence table memorized in the aforementioned memory 10a, determines the slider action for control according to the preset action data, and performs calculation processing when it is in the continuous operation mode. (2) The slider moves in accordance with the determined action, and based on the deviation between the target position and the position input from the position sensor 33, the speed command of the servo motor 21 is obtained and output to the servo amplifier 45. In addition, in the jog mode or the safe one-stroke mode, in order to keep the slider only in the operation of an operation button switch (not shown) (however, in the safe one-stroke mode, once the lower dead point is exceeded, the operation button operation , Also continuously rises to the top dead point and stops) moves at a certain speed, finds the speed command of the servo motor 21 according to the deviation between the target 値 and the position input from the position sensor 33, and outputs it to the servo amplifier 45. Further, during the drive of the servo motor 21 as described above, the controller 10 outputs the load current of the servo motor 21 during driving from the current sensor 29. According to this load state, the servo motor 21 is raised to a predetermined level before reaching the overload state. Distance to reduce the load, thereby preventing the occurrence of abnormal motor overload. Various information such as the current position of the slider, the current of the servo motor, and the overload status are further monitored, and a display instruction is output to the monitor 19. The motor rotation 13 200400108 angle from the servo motor rotation angle sensor (not shown) is fed back to the servo amplifier 45. The servo amplifier 45 calculates the deviation 値 between the speed command from the controller 10 and the speed feedback signal obtained from the motor rotation angle, and controls the servo motor 21 to reduce the deviation 偏 based on the obtained deviation 値. Thereby, the position and speed of the slider can be controlled with high precision. Next, the processing sequence of the first embodiment of the motor overload protection method according to the present invention will be described with reference to FIG. 5 according to the control flowchart shown in FIG. 4. FIG. 5 is a time chart of the position of the slider, the torque generated by the motor, and the accumulated heat in the motor overload protection method according to the first embodiment. In FIG. 4, first, the first heat accumulation threshold 値 Qsl and the second heat accumulation threshold 値 Qs2 are set to predetermined 在 in step si. As shown in FIG. 5, this first heat accumulation threshold sQsl is a threshold 检查 for checking the timing of the temporary stop control to achieve the overload protection of the motor, and it is set to be smaller than the heat-resistant capacity threshold 値 Qm of the servo motor 21, that is, less than the corresponding The maximum allowable heat accumulation of the overload abnormality does not reach the predetermined value (equivalent to the adequacy). In addition, the second heat accumulation threshold Qs2 is a threshold for checking the timing of releasing the temporary stop and restarting, and the motor temperature corresponds to the temperature when the temperature is lower than the temperature during the temporary stop and reaches a predetermined temperature. In addition, although the relationship between the first heat accumulation threshold 値 Qsl ^ and the second heat accumulation threshold 値 Qs2 can be set, in order to stabilize the temporary stop and restart, it is preferable that the first heat accumulation threshold 値 (^ 1 > the second heat accumulation The threshold 値 Qs2, 俾 has the hysteresis phenomenon of temperature monitoring. Moreover, the real currents used for the following calculation processes are initialized (divided) Tables II to In. Here, η is the cumulative heat quantity obtained by the following operation, Qn can be equivalently expressed The number of data of the degree of temperature of the motor. Secondly, in step s2, the current 値 In 14 200400108 in the operation of the servo motor 21 is detected, and it is stored in the measured current 値 table Π to In. Further, in step 3, the formula "Qn = Σ in · Kn "calculates the cumulative heat quantity 値 Qn. Here, kn (n = 1 to η) is a coefficient corresponding to time-weighted to reduce its effect from the measurement time, where 0 $ kn-1 S kn. After that, At step s4, the data of the measured current (Table II to In) is shifted according to "In 1-1 —In". As a result, the data of the oldest past measured 値 11 is eliminated. And, the step s5 is followed to check the calculated heat accumulation 値Does Qn When the first heat accumulation threshold 値 Qsl or more, when it is not above the first heat accumulation threshold 値 Qsl, return to step s2 and repeat the above processing. In the above step s5, when it is higher than the first heat accumulation threshold 値 Qsl, proceed to step s6, temporarily stop the slider at a predetermined position outside the forming field (such as a preset standby point or top dead point, etc.), and simultaneously display a warning message such as "temporarily stopped" on the monitor display 19. Moreover, it can also be notified by sound Temporarily stopped ". After that, the current 値 In of the servo motor 21 is detected in step s7, and it is memorized in the aforementioned measured currents 値 Tables II to In. Second, in step s8, the same calculation formula as" Qn = EIn · "is used. Kn ”calculates the heat accumulation 値 Qn, and further proceeds to step s9, such as“ In-1 —In ”displacement measured current 値 table II to In data, proceeds to step slO, and checks whether the newly obtained heat accumulation 値 Qn is in the first 2 heat accumulation 値 Qs2 or less. When it is not below the second heat accumulation threshold 値 Qs2, go back to step s7 and repeat the above process. When it is lower than the second heat accumulation threshold 値 Qs2, release the temporary at step si 1 Stop, the state of restarting the slider, and then return to step s2, and repeat the process. In addition, the state of the slider restart in step s11 is in the case of automatic operation 15 200400108 continuous operation mode, and then restart the continuous operation state, and In the case of an external safety one-stroke mode that operates synchronously with a transfer feeder such as a transfer press, if there is a start request waiting state for the start request signal from the transfer feed device, the start request wait state, etc. Second, borrow Fig. 5 illustrates the operation of the above method. In Fig. 5, at time t0, the operation button is operated in the continuous operation mode to continuously start the press. Since the controller 10 controls the position and speed of the servo motor 21 so that the slider moves according to a preset slider motion mode, the load current flows to the servo motor 21 in a pattern corresponding to the above-mentioned slider motion. As the load current corresponding to the same operation of the slider 1 (week time Tc) continues to flow every week, the temperature of the servo motor 21 gradually increases. The controller 10 measures the motor current 値 In during this period. Based on the measured data of the motor current 値 In until this time, it calculates the heat accumulation 借 Q7 by the formula "Qn = Σ In · Kn" (which is roughly equal to the increase in motor temperature). Ratio) (steps s2, s3). Then, it is checked whether the heat accumulation 値 Qn obtained this time in continuous operation is above a predetermined first heat accumulation threshold 値 Qsl (step s5), and when it is not above the first heat accumulation threshold 値 Qsl, the first heat accumulation threshold 値QS1 follows the above-mentioned processing. And in the calculation of the heat accumulation 値 Qn, the actual current measurement in the past uses the weighting coefficient kn to reduce the effect on temperature rise corresponding to the elapsed time (step S4). And, at time t2, when the heat accumulation 値 Qn obtained this time is above the first heat accumulation threshold 値 Qsl, after the end of the current running cycle, at time t3, the slider is temporarily stopped at a predetermined position outside the forming field. (Step s6). Thereby, the load current of the servo motor 21 is reduced to the small current required by the position protection 16 200400108. The heat accumulation 値 Qn is reduced, that is, the large power semiconductors of the power circuit in the servo motor 21 and the servo amplifier are sharply reduced. Component temperature. After that, the motor current 値 In is continuously monitored, and the heat accumulation 値 Qn is obtained based on the motor current 値 In detected for each predetermined calculation processing cycle time and the actual measurement of the past motor current 値 Qn (steps S7, 8, 9). Until the obtained latest calorie accumulation 値 Qn is lower than the second calorie accumulation threshold 値 Qs2, it is temporarily stopped (step sl10). And, if this heat accumulation 値 Qn is lower than the second heat accumulation threshold 値 Qs2 (time t4 in FIG. 5), the slider is set to the restart state (step s11). In addition, although the above-mentioned embodiment is described as an example of a servo press that is applicable to a structure in which the eccentric shaft 28 is rotated by the servo motor 21 and the rotational power is used to drive the slider 3 through the toggle link mechanism, the present invention is not limited to this. Direct drive type servo press that can directly drive the screw nut by the servo press to directly drive the slide, or it can also be applied to the eccentric rotation drive unit by the servo motor through the link mechanism or eccentric mechanism. And the servo press of the linkage lifting drive slider, or the servo press of the elbow linkage mechanism driven by the screw nut push and pull. In the embodiment, the amount of heat accumulation 値 obtained through calculation based on the actual measurement data of the motor load current ’is monitored, but it is also possible to monitor the temperature of the motor instead of the heat accumulation 値. In addition, the conditions for canceling the temporary stop and restart are not limited to the method for determining whether the motor temperature (heat accumulation 値) is below a predetermined second heat accumulation threshold 値 Qs2 as described above. For example, the motor temperature (heat accumulation 5) Ten) It may be ok to start after the amount of time has passed. 17 200400108 Next, a second embodiment will be described with reference to Figs. The control structure of the second embodiment is the same as that shown in FIG. 3. First, the processing procedure of the second embodiment will be described with reference to Fig. 6. Fig. 6 is a control flow chart of the second embodiment. The steps with the same processing contents as those in Fig. 4 in the same figure are marked with the same step numbers, and the description is omitted. Steps si to S5 are performed in the same order as in the first embodiment. In step s5, it is checked whether the previously obtained heat accumulation nQn is above the first quantity accumulation threshold 値 Qsl, and when it is higher than the first heat accumulation 値 Qsl, in step s21, in this case (even during pressurization) temporarily stop. Next, at step s22, the current 値 Is of the servo motor 21 during stop is detected, and at step s23, it is checked whether the current 値 Is is above the predetermined allowable 値 Ir, and when it is less than the allowable 値 Ir, go to step s6, and continue with the current slider The temporary stop position. When the current 値 15 is higher than the predetermined allowable 値 Ir in the above step s23, the servo motor 21 is driven in the direction of decreasing the load of the motor in step s24 by a predetermined amount, that is, the slider 3 is raised from the stop position at this time to a predetermined distance. Thereafter, the slider 3 is temporarily stopped at the aforementioned step s6, and thereafter, the processes of the aforementioned steps S7 to s11 are performed. Next, an operation of the second embodiment will be described with reference to FIG. 7. As in the first embodiment, if the press is operated in the continuous operation mode after the time to, the load current flows to the servo motor 21 in a pattern corresponding to the action of the slider. With this, the temperature of the servo motor 21 gradually rises. During this period, the controller 10 measures the motor current 値 In. Based on the measured data of the motor current 借 In so far, it calculates the heat accumulation 値 Qn using the formula "Qn = ΣΙη · Kn" (steps s2, s3). And, during continuous operation, the cumulative amount of heat obtained this time is detected. 200400108
Qn是否在既定第1熱量計閾値Qsi以上（步驟S5)，於其 不在第1熱量累計閾値Qsl以上時，在達到第1熱量累計 閾値Qsl之前，繼續上述處理。 此後，於時刻t2，當此次求得之熱量累計値Qn在第1 熱量累計閾値Qsl以上時，即使於藉滑件3加壓加工中， 亦於此情形下暫時停止伺服馬達21 (步驟s21)。其次， 檢查停止中之馬達電流値Is是否在既定電流値Ir以上（步 驟s22、s23)，由於在其高於容許値Ir時，加壓轉矩施加 於伺服馬達，故於圖示之時刻t2，上昇滑件3達既定距離 (步驟s24)，在爲成無此加壓轉矩施加之狀態之後，暫時 停止（步驟s6)。藉此，將伺服馬達21之負載電流減少成 滑件位置保持所需大小程度之電流，謀求熱量累計値Qn之 減少，亦即，急遽降低伺服馬達21及伺服放大器內電源電 路之大電力半導體元件之溫度。且此後之暫時停止狀態至 再起動之次序與前述步驟s7至步驟sll相同，省略其說明 〇 根據第2實施形態，由於獲得與第1實施形態相同之 效果，並且，進一步在熱量累計値超過第1熱量累計閾値 Qsl情形下，馬上停止滑件，此後暫時停止滑件於馬達負載 電流小之位置，並由於前述第1熱量累計閾値Qsl可僅具 有相對於達到過載異常之容許熱量極小之充裕度，可將伺 服馬達21使用到接近此最大負載能力之最大限度。 根據本發明，獲得如下效果。 藉由預先設定對應低於造成馬達過載異常之馬達最大 200400108 容許溫度達既定量之溫度之第1熱量累計閾値，對應於歷 經時間加權累計馬達作動中（亦包含流出負載電流以保持 滑件於停止位置時），就每一既定週期時間測得之馬達負 載電流値，求出大致等效表示馬達溫度上昇之熱量累計値 Qn，在此逐次求出之熱量累計値Qn超過前述設定之第1熱 量累計閾値Qsl時，暫時停止滑件，俾降低馬達溫度。由 於在壓機連續運轉模式或外部安全一行程模式運轉等之自 動運轉中，於出現馬達過載異常之前，暫時停止滑件，以 降低馬達溫度，故可防止馬達過載異常發生於未然，藉此 ，無需如習知技術所示馬達過載異常發生後之再起動操作 ，可提高操作性及作業性。 又，消除如習知技術因在工作加工中之過載異常發生 所造成滑件停止而生產不良加工品之情形。此外，在滑件 之暫時停止位置處於滑件待機點或上死點情形下，容易與 轉移進料器聯動而運轉，可實現自動運轉。 再者，由於在因上述溫度上昇而暫時停止中，顯示「 暫時停止中」之警告信息於監視顯示器19，故作業員可容 易掌握停止主要因素，可使其放心。 【圖式簡單說明】 (一）圖式部分 圖1係適用本發明之伺服壓機之側面局部截面圖。 圖2係適用本發明之伺服壓機之側面局部截面圖。 圖3係本發明控制構造之方塊圖。 圖4係第1實施形態之控制流程圖。 20 200400108 圖5係第1實施形態之馬達過載保護方法之時間圖 表。 圖6係第2實施形態之控制流程圖。 圖7係第2實施形態之馬達過載保護方法之時間圖 表。 (二）元件代表符號 1 伺服壓機 3 滑件 4 底座 5 承梁 6 油室 7 螺軸 9 感應馬達 10 控制器 10a 記憶體 11 柱塞 12a 第1連桿 12b 第2連桿 13 三軸連桿 16 切換閥 19 監視顯示器 20 滑件驅動部 21 伺服馬達 22a 第1滑輪Whether Qn is above the predetermined first calorimeter threshold 値 Qsi (step S5), and if it is not above the first caloric accumulation threshold 値 Qsl, the above processing is continued until the first caloric accumulation threshold 値 Qsl is reached. Thereafter, at time t2, when the heat accumulation 値 Qn obtained this time is above the first heat accumulation threshold 値 Qsl, the servo motor 21 is temporarily stopped in this case even during the pressurizing process of the slider 3 (step s21). ). Next, check whether the motor current 値 Is during stopping is greater than the predetermined current 値 Ir (steps s22, s23). Since it is higher than the allowable 値 Ir, the pressurizing torque is applied to the servo motor, so at the time t2 in the figure When the rising slider 3 reaches a predetermined distance (step s24), it stops temporarily after the pressure torque is not applied (step s6). Thereby, the load current of the servo motor 21 is reduced to a current of the magnitude required to maintain the position of the slider, and the heat accumulation 値 Qn is reduced, that is, the large power semiconductor components of the power circuit in the servo motor 21 and the servo amplifier are reduced sharply. Of temperature. And the order from the temporary stop state to the restart after that is the same as the above steps s7 to s11, and the description is omitted. According to the second embodiment, the same effect as that of the first embodiment is obtained, and the heat accumulation further exceeds the 1 In the case of the heat accumulation threshold 値 Qsl, stop the slider immediately, and then temporarily stop the slider at a position where the motor load current is small, and because the aforementioned first heat accumulation threshold 値 Qsl can only have a margin that is extremely small compared to the allowable heat that reaches the overload abnormality , The servo motor 21 can be used to approach the maximum of this maximum load capacity. According to the present invention, the following effects are obtained. By presetting the first heat accumulation threshold corresponding to the maximum 200400108 allowable temperature of the motor that caused the motor overload abnormality to reach a predetermined amount of temperature, it corresponds to the elapsed time-weighted accumulation motor in operation (including the load current flowing to keep the slider stopped) Position), based on the motor load current 每一 measured at each predetermined cycle time, find the heat equivalent 値 Qn which is approximately equivalent to the increase in motor temperature. Here, the heat cumulation 逐 Qn which is obtained successively exceeds the first heat set above. When the accumulated threshold 値 Qsl, the slider is temporarily stopped to reduce the motor temperature. In automatic operation such as continuous operation mode of the press or external safety one-stroke mode operation, before the motor overload abnormality occurs, the slider is temporarily stopped to reduce the temperature of the motor, so that the motor overload abnormality can be prevented from happening. It is not necessary to restart the motor after an abnormal motor overload occurs as shown in the conventional technology, which can improve operability and workability. In addition, it eliminates the situation where the conventional technology produces a badly processed product due to the stoppage of the slider due to the abnormality of the overload during work processing. In addition, when the temporary stop position of the slider is at the slider standby or top dead point, it is easy to operate in conjunction with the transfer feeder, and automatic operation can be realized. Furthermore, since the warning message "Temporarily stopped" is displayed on the monitor 19 during the temporary stop due to the temperature rise, the operator can easily grasp the main factors of the stop and can be assured. [Brief description of the drawings] (I) Schematic part Fig. 1 is a partial cross-sectional side view of a servo press to which the present invention is applied. Fig. 2 is a partial side sectional view of a servo press to which the present invention is applied. Fig. 3 is a block diagram of a control structure of the present invention. Fig. 4 is a control flowchart of the first embodiment. 20 200400108 Fig. 5 is a time chart of the motor overload protection method of the first embodiment. Fig. 6 is a control flowchart of the second embodiment. Fig. 7 is a timing chart of the motor overload protection method of the second embodiment. (II) Symbols for components 1 Servo press 3 Slide 4 Base 5 Bearing beam 6 Oil chamber 7 Screw shaft 9 Induction motor 10 Controller 10a Memory 11 Plunger 12a First link 12b Second link 13 Three-axis connection Stem 16 Switching valve 19 Monitor 20 Slider drive unit 21 Servo motor 22a First pulley
21 200400108 22b 第2滑輪 23 皮帶 27 驅動軸 28 偏心軸 29 電流感測器 33 位置感測器 34 輔助架 45 伺服放大器21 200400108 22b 2nd pulley 23 Belt 27 Drive shaft 28 Eccentric shaft 29 Current sensor 33 Position sensor 34 Auxiliary frame 45 Servo amplifier
22twenty two