1269705 玖、發明說萌 【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 0 【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。 1269705 曰本特許文獻1 曰本特開平10- 277797號公報 曰本特許文獻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， 1269705 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 1269705 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 1269705 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Ha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 後述之滑件驅動部20之偏心軸28。桌1連桿12a、苐2連 桿12b以及三軸連桿13構成时節連桿機構。 1269705 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 籲 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。逋過切換閥16供至油室6內之操作油在衝壓加〇：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 11 1269705 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 1269705 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 1269705 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 量累計閾値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熱量累計閩値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 1269705 ，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，其中〇 S 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II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Qs 1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熱量累計閾値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= ΣΙη · 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、 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 1269705 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 熱重累i十閾値Qsl以上時’在達到第1熱量累計閾値qsi 之前繼續上述之處理。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在第工 熱量累g十閾値Qs 1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 1269705 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sl〇)。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 累計値）達既定量之時間經過之後再起動亦無妨。 17 1269705 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s 11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t0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10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 18 12697051269705 玖,发明说萌 [Technical Field of the Invention] The present invention relates to a motor overload protection method for a servo press, in which a servo press that drives a slider by a servo motor through a predetermined power transmission mechanism prevents automatic operation of the press The overload of the servo motor for the slider drive is abnormal. 0 [Prior Art] The servo motor is reciprocally driven by a predetermined power transmission mechanism such as a ball screw, a toggle link mechanism, a crank mechanism or an eccentric mechanism by a servo motor. The servo can be controlled by the position and speed of the servo motor to control the slider to be a slider movement suitable for the workpiece processing conditions, and has an excellent advantage. In addition, it is widely used in recent years (for example, refer to Japanese Patent No. 1 and Japanese Patent No. 2) because of the high-precision forming process and the improvement in productivity due to the increase in the number of strokes. . In the above-described servo press, when the workpiece machining is continuously performed in the automatic operation mode, the temperature of the servo motor gradually rises due to the continuously changing load current of the servo motor. That is, the energy equivalent to the workload of the servo motor effective output torque causes the servo motor to generate heat. Generally, the maximum allowable output current of the servo motor is limited by the ambient temperature and the temperature of the motor itself. Therefore, the temperature of the motor itself exceeds the predetermined maximum allowable temperature, that is, by the thermal monitoring function of the servo amplifier, the warning signal of the overload abnormality is output.作 Thermal protection of the servo motor. At this time, as soon as the 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 also cut off, and the output of the current to the servo motor is cut off. 1269705 曰本本本本本本本本本本本本本本本本本本本本本本本本本本本本本本本本本 No. No. 2002-175831, however, in the above-mentioned conventional servo press, motor overload occurs when the press is continuously operated Abnormal, that is, as described above, the servo amplifier cuts off the motor current output, and the main circuit power supply is also turned off. Therefore, in order to cancel the abnormal stop of the overload of the servo amplifier, it is necessary to wait for the control power of the servo amplifier to be temporarily turned off. When the motor temperature drops below the predetermined threshold, the operation of the control power supply and the main circuit power supply is turned on again. Therefore, if a temporary overload abnormality alarm occurs, it takes time to restart the press, and the productivity of the automatic operation is lowered. In addition, when the servo motor is stopped due to a sudden overload abnormality during automatic operation, if the workpiece is being processed, not only a defective product but also a defective workpiece is required to be restarted, and it is necessary to raise the slider from the stop state of the slider and return to the standby point. The troublesome operation of discharging the defective processed product from the mold and restarting thereafter, and also has a problem of time consuming. SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object thereof is to provide a motor overload protection method for a servo compressor, which can prevent an abnormality of a servo motor from being overloaded even during automatic operation of the press. In order to achieve the above object, a 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; and detects a load current when the servo motor is actuated, 1269705 is automatically During the operation, the heat accumulation 値 is obtained based on the past measured 包含 including the detected motor load current, and when the obtained heat accumulation 値 exceeds the first heat accumulation threshold ,, the slider is temporarily stopped at a predetermined position other than the molding area. According to the first aspect of the invention, since the motor heat accumulation 大致 which is substantially proportional to the motor temperature is monitored, the motor heat accumulation 暂时 reaches the first heat accumulation threshold 値, that is, the slider is temporarily stopped, and the motor temperature is lowered before the overload abnormality occurs, so that the motor can be prevented. An overload abnormality in automatic operation occurs before it occurs. Therefore, the long-term operation interruption or restart operation caused by the occurrence of an overload abnormality can improve productivity and workability. In addition, no defective processed products will be produced. Further, the above-mentioned forming field refers to a field in which the slider is formed by pressurizing the workpiece or pressing the die pad down. A second invention is a motor overload protection method for a servo press, wherein the servo pressure is driven by a predetermined power transmission mechanism by a servo motor; and the load current when the servo motor is activated is detected, and in the automatic operation, according to the inclusion When the motor load current is detected, the heat is accumulated, and when the calculated heat accumulation 値 exceeds the first heat accumulation threshold ,, the slider is temporarily stopped, and thereafter, when the current motor load current is detected to be higher than the predetermined 値, The slider is raised by a predetermined distance and temporarily stopped. According to the second aspect of the invention, since the motor heat amount 値 which is substantially proportional to the motor temperature is monitored, the predetermined first heat amount accumulation threshold 达到 is reached, that is, the slider is temporarily stopped, and thereafter, when the current motor load current 既 is equal to or greater than a predetermined level, In other words, when the servo motor is stopped under the state of the rated torque of more than 既, in order to reduce the motor load, the slider is raised by a predetermined distance and temporarily stopped, so that the motor load current can be reduced before the overload abnormality occurs. Both 1269705 are fixed below. Since the motor temperature is thereby lowered, it is possible to prevent an overload abnormality in the automatic operation from occurring. Therefore, it is possible to improve the productivity and workability by eliminating the interruption of the long-time operation caused by the occurrence of the overload abnormality or the operation for restarting. In addition, no defective processed products will be produced. According to a third aspect of the invention, in the first or second aspect of the invention, after the slider is temporarily stopped, the motor load current is detected again, and the amount of heat obtained by the actual measurement is included based on the motor load current detected at this time. When it is lower than the second heat accumulation threshold ,, the temporary stop of the slider is released, and the state is restarted. According to the third aspect of the invention, when the motor heat accumulation level is lower than the second heat amount accumulation threshold ,, that is, the temporary stop is released, and the restart state is reached, that is, in the continuous operation mode, the operation is resumed, or for example, external safety. In the stroke mode, the transfer feeder is set to wait for the start of the press, so the automatic operation can be continued. This allows you to monitor the motor temperature and prevent the motor from overloading and operate automatically. Further, when the standby point is temporarily stopped, the operation synchronized with the transfer feeder or the like can be easily resumed. According to a fourth aspect of the invention, in the first or second aspect of the invention, after the temporary stop of the slider, when the predetermined time elapses, the temporary stop of the slider is released and the state is restarted. According to the fourth aspect of the invention, the automatic operation can be continued when the predetermined time (the predetermined temperature required for the motor temperature to decrease) is reached after the temporary stop, that is, the restart state (as described above). In this way, the motor temperature can be monitored on one side, and the motor can be automatically operated while avoiding abnormal motor overload. Further, when the standby point is temporarily stopped, the operation of synchronizing the feeder 1269705 with the transfer feeder or the like can be easily resumed. [Embodiment] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. First, the configuration of a servo press to which the present invention is applied will be described with reference to Figs. 1 and 2. Fig. 1 and Fig. 2 are respectively a partial cross-sectional side view and a rear partial cross-sectional view of the servo press. The press machine 1 series servo press (hereinafter referred to as servo press 1) drives the slider 3 by the servo motor 21. The slider 3 is movably supported by a substantially central portion of the main body frame 2 of the servo press 1 so as to be vertically movable, and a bolster 5 attached to the base 4 is disposed below the slider 3. The body portion of the screw closing height adjustment screw shaft 7 is rotatably inserted into the hole formed in the upper portion of the slider 3 in a state of preventing the loosening. The screw portion 7a of the screw shaft 7 is exposed upward from the slider 3, and is screwed to the female screw portion of the lower portion of the plunger 11 provided above the screw shaft 7. The worm wheel 8a of the worm gear unit 8 is attached to the outer circumference of the main body portion of the screw shaft 7. The worm 8b of the worm gear unit 8 screwed to the worm wheel 8a is coupled to the output shaft of the induction motor 9 attached to the rear surface portion of the slider 3 via the gear 9a. The induction motor 9 has a short axial length and is configured to be small. The upper portion of the plunger 11 is rotatably coupled to one end of the first link 12a, and the other end of the first link 12a and the one end are rotatably coupled to the second link of the body frame 2 Between the other end portions of the 12b, the two connection hole pins 14a and 14b provided on the side of the three-axis link 13 are rotatably coupled. The coupling hole on the other side of the triaxial link 13 is rotatably coupled to the eccentric shaft 28 of the slider driving portion 20 which will be described later. The table 1 link 12a, the 苐2 link 12b, and the three-axis link 13 constitute a time link mechanism. 1269705 The servo motor 21 for sliding member drive is attached to the side surface portion of the main body frame 2 with the axial center in the left-right direction of the press, and the belt 23 (usually composed of a fixed belt) is wound around the first output shaft of the servo motor 21 The pulley 22a is rotatably disposed between the second pulley 22b of the intermediate shaft 24, which is rotatably disposed in the left-right direction of the press toward the compressor. Further, the drive shaft 27 is rotatably supported by the body frame 2 above the intermediate shaft 24, and the gear 26 attached to one end side of the drive shaft 27 meshes with the gear 25 attached to the intermediate shaft 24. Further, 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 above-described three-axis link 13 is rotatably coupled to the eccentric position of the outer peripheral portion of the eccentric shaft 28. An oil chamber 6 sealed from the lower end surface portion 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 to the inside of the oil chamber 6. The operating oil supplied to the oil chamber 6 through the switching valve 16 is pressed in the press: time - occluded in the oil chamber 6, and the oil passing through the oil chamber 6 transmits the pressing force to the slider 3 when pressurized. If an overload is applied to the slider 3, the oil pressure in the oil chamber 6 exceeds a predetermined enthalpy, and the oil is returned to the oil sump from the unillustrated safety valve, and the slider 3 is buffered to be quantitative, so that the slider 3 and the mold are not damaged. Further, a pair of brackets 31, 31 projecting from the upper and lower sides toward the side surface portion of the main body frame 2 are attached to the rear surface portion of the carriage 3, and the position detecting lever 32 is attached between the upper and lower pairs of brackets 31, 31. The body portion of the position sensor 33 such as a linear scale is movably inserted up and down in the position detecting lever 32 provided with the position detecting scale portion. The position sensor 33 is fixed to the auxiliary frame 34 provided at the side portion of the body frame 2. The auxiliary frame 34 is formed to extend in the vertical direction 11 1269705 in the vertical direction, and the lower portion is attached to the side surface portion of the main body frame 2 by the bolts 35, and the upper portion is slidably supported by the bolts 36 inserted into the long holes in the upper and lower directions, not shown, in the vertical direction. The first and second pairs of support members 37 and 37 are abutted and supported. Since the auxiliary frame 34 is formed such that only one of the upper and lower sides (the lower side in this example) is fixed to the main body frame 2, and the other side is movably supported up and down, the main frame 2 is not subjected to temperature change. The telescopic effect that occurs. Thereby, the position sensor 33 is not affected by the expansion and contraction of the body frame 2 due to the temperature change, and the position of the slider and the die height can be correctly detected. Secondly, according to the control structure block shown in FIG. The figure illustrates the hardware configuration of the control device. The controller 10 of the control device includes a memory unit 10a, a monitor display unit 19, a current sensor 29, a position sensor 33, a servo amplifier 45, and a slider drive servo motor 21. The current sensor 29 detects the load current of the servo motor 21, and outputs the detected current 値 to the controller 10. Further, the position sensor 33 outputs the detected slider position to the controller 10. The memory 10a memorizes the preset slider movement data and the table data indicating the relationship between the slider position and the rotation angle of the servo motor 21. Further, this relationship is determined by the eccentric length of the eccentric shaft 28, the length of each link of the above-described toggle link mechanism, the rotational center position of the eccentric shaft 28, and the relationship between the toggle link and the like. Further, the monitor display 19 displays various monitoring information, warning information, and the like such as the current position (height) of the slider, the motor load current 此时 at this time, and the calculation of the motor load state based on the display command from the controller 10. The display may be constituted by a digital display such as an LED (light emitting diode), a text display such as a liquid crystal, or a graphic display. Further, the controller 10 is constituted by a high-speed arithmetic device such as a computer device or a PLL (programmable logic controller, so-called programmable sequencer). The controller 10 refers to the slider position/motor rotation angle correspondence table stored in the memory l〇a, and determines the slider operation for control according to the preset operation data, and performs arithmetic processing when the continuous operation mode is performed. The jaw slider moves in accordance with the determined motion, and the speed command of the servo motor 21 is obtained based on the deviation between the target position and the position input from the position sensor 33, and is output to the servo amplifier 45. Further, in the jog mode or the safe one-stroke mode, in order to make the slider operate only in the operation button switch (not shown) (however, in the safe one-stroke mode, one exceeds the bottom dead center, that is, although the operation button operation is performed The vehicle is also moved to the servo amplifier 45 based on the deviation between the target 値 and the position input from the position sensor 33. Further, during the driving of the servo motor 21 as described above, the controller 10 outputs the load current 値 of the servo motor 21 in the driving from the current sensor 29, and according to the load state, the servo motor 21 is raised until the overload state is reached. The distance is reduced to prevent the motor overload abnormality from happening. Further monitoring various information such as the current slider position, servo motor current 値, and overload state, and outputting the display command to the monitor display 19. The motor rotation 13 1269705 from a 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 based on the determined deviation 以 to reduce the deviation 値. Thereby, the position and speed of the slider are controlled with high precision. Next, the processing procedure of the first embodiment of the motor overload protection method of the present invention will be described with reference to Fig. 5, based on the control flow chart shown in Fig. 4. Fig. 5 is a time chart of the slider position, the motor generated torque, and the heat accumulation 之 of the motor overload protection method according to the first embodiment. In Fig. 4, first, in step si, the first heat accumulation threshold 値Qs1 and the second heat accumulation threshold 値Qs2 are set to predetermined 値. As shown in FIG. 5, the first heat accumulation threshold 値Qsl is a threshold for checking the timing of the temporary stop control by the motor overload protection, and is set to be smaller than the heat resistance capacity threshold 値Qm of the servo motor 21, that is, less than the corresponding The maximum allowable heat accumulation of the overload abnormality is equal to both the quantitative (equivalent to the sufficient degree). Further, the second heat amount accumulation threshold 値Qs2 is a threshold for the timing at which the inspection is temporarily stopped and restarted, and the motor temperature corresponds to a temperature lower than the temperature at the time of the temporary stop to a predetermined temperature. Further, although the relationship between the first heat accumulation 闽値Qs1 and the second heat accumulation threshold 値Qs2 can be set, in order to stably control the temporary stop and restart, it is preferable that the first heat accumulation threshold ^(^1>2nd heat The cumulative threshold 値Qs2, 俾 has a hysteresis of temperature monitoring, and initializes (destroys) the real current used for the following arithmetic processing 値 Table II to In. Here, η is the heat calculation obtained by the following operation 値Qn is equivalent The number of data indicating the degree of the motor temperature is determined. Next, in step s2, the current 値In 14 1269705 in the operation of the servo motor 21 is detected, and it is stored in the measured current 値 table to In, and further in step 3, the formula "Qn= Σ In · kn" calculates the heat accumulation 値Qn. Here, kn ( n = 1 to η) is a coefficient corresponding to the time-weighted time from the measurement time to reduce the degree of action, where 〇S kn - 1 S kn. In step s4, according to "In 1 - In", the measured current is shown in Table II to In, and as a result, the data of the oldest past measured 値 II is eliminated, and secondly, the obtained heat is accumulated in step s5.値Qn whether When the first heat accumulation threshold 値Qs1 or more is not equal to or greater than the calorie accumulation threshold 値Qs1, the process returns to step s2, and the above process is repeated. When the step S5 is higher than the first heat accumulation threshold 値Qs1, the process proceeds to the step. S6, the slider is temporarily stopped at a predetermined position other than the forming area (for example, a preset standby point or a top dead center), and a warning message such as "temporarily stopped" is displayed on the monitor display 19. Further, the slider can be notified by voice. Thereafter, the current 値In of the servo motor 21 is detected in step s7, and is stored in the measured currents 値 to II, and then, in step s8, the same equation as the previous formula "Qn= ΣΙ η" is used. Kn" calculation heat accumulation 値Qn, further in step s9, such as "In-1 - In" displacement measured current 値 Table II to In data, proceeds to step s10, check 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, the process returns to step s7, and the above process is repeated. When it is lower than the second heat accumulation threshold 値Qs2, the solution is in step si. Temporarily stopped, the state of restarting the slider, and then returning to step s2, and repeating the processing. Further, the shutter restarting state of step s11 is resumed in the continuous operation state in the case of the automatic operation mode 15 1269705 continuous operation mode, for example. Further, in the case of the external safety one-stroke mode in which the transfer feeder is operated in synchronization with the transfer press, etc., the start request waiting state, etc., which can be started from the press start request signal of the transfer feeder, etc. The operation of the above method will be described with reference to Fig. 5. In Fig. 5, at time t0, the operation button is operated in the continuous operation mode, and the press is continuously started. Since the controller 10 controls the position and speed of the servo motor 21 to move the slider in accordance with the preset slider movement mode, the load current flows to the servo motor 21 in a pattern corresponding to the movement of the slider. As the load current corresponding to the operation of the slider 1 (week time Tc) continues to flow every one week, the temperature of the servo motor 21 gradually rises. The controller 1 〇 measures the motor current 値In during this period, and based on the measured data of the motor current 値In until now, the heat accumulation 値Q7 is calculated by the formula “Qn = Σ In · Kn” (which roughly rises with the motor temperature). Proportion) (steps s2, s3). Further, it is checked whether or not the heat accumulation 値Qn obtained this time in the continuous operation is equal to or greater than the predetermined first heat accumulation threshold 値Qs1 (step s5), and when it is not above the first heat weight, the tenth threshold 値Qsl or more, the first time is reached. The above processing is continued before the heat accumulation threshold 値qsi. Further, in the calculation of the heat accumulation 値Qn, the past current is measured by the weighting factor kn, and the degree of effect on the temperature rise is reduced in accordance with the elapsed time (step s4). Further, at time t2, when the heat accumulation enthalpy Qn obtained this time is equal to or greater than the first heat load deg Q 値 Qs 1 or later, after the end of the current operation cycle, at time t3, the slider is temporarily stopped outside the molding field. The established position (step s6). Thereby, the load current of the servo motor 21 is reduced to a small current required for the position protection 16 1269705, and the heat accumulation 値Qn is reduced, that is, the large power semiconductor of the power supply circuit in the servo motor 21 and the servo amplifier is rapidly reduced. The temperature of the component. Thereafter, the motor current 値In is continuously monitored, and the heat accumulation 値Qn is obtained based on the measured data of the detected motor current 値In and the past motor current for each predetermined calculation processing cycle time (steps S7, 8, and 9). The latest heat accumulation 値Qn obtained is lower than the second heat accumulation threshold 値Qs2, and the temporary stop is continued (step s1〇). Further, if the 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). Further, although the above-described embodiment is applied to an example of a servo press that is applied to a structure in which the eccentric shaft 28 is rotated by the servo motor 21, thereby rotating the power and driving the slider 3 through the toggle link mechanism, the present invention is not limited thereto, for example. The direct drive type servo press can directly drive the screw nut by the servo press, thereby directly driving the sliding member, or can be applied to the eccentric rotating drive unit such as the link mechanism or the eccentric mechanism by the servo motor. And the servo press for connecting the lever to drive the sliding member, or pushing and pulling the servo press of the toggle link mechanism by the screw nut. Further, although the embodiment monitors the actual amount of heat calculated based on the motor load current 値 and calculates the amount of heat accumulated, the motor temperature can be monitored instead of the heat accumulation 値. Further, the condition for canceling the temporary stop and restart is not limited to the method of determining whether or not the motor temperature (heat accumulation 値) is equal to or lower than the predetermined second heat accumulation threshold 値Qs2, for example, reducing the motor temperature as much as possible (heat accumulation 値It is no problem to start after the time has passed. 17 1269705 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, and the same steps as those in Fig. 4 are denoted by the same step numbers, and the description thereof will be omitted. The processing is performed in the same order as in the first embodiment from step si to step S5. In step s5, it is checked whether the obtained heat accumulation 値Qn is equal to or greater than the first amount accumulation threshold 値Qsl, and when it is higher than the first heat accumulation 値Qs1, in step s21, in this case (even during pressurization processing) stop. Next, in step s22, the current 値Is in the stop of the servo motor 21 is detected, and in 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, the process goes to step s6 to continue the current slider 3. 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 to the motor load reduction direction in step s24 to be quantitative, that is, the slider 3 is raised from the stop position at this time by a predetermined distance. Thereafter, the slider 3 is temporarily stopped in the aforementioned step s6, and then the processing of the foregoing steps s7 to s 11 is performed. Next, the operation of the second embodiment will be described with reference to Fig. 7 . As in the first embodiment, when the press is operated in the continuous operation mode after time t0, the load current flows to the servo motor 21 in a pattern corresponding to the operation of the slider. Accordingly, the temperature of the servo motor 21 gradually rises. During this period, the controller 10 measures the motor current 値In, and calculates the heat accumulation 値Qn by the calculation formula "Qn = ΣΙη · Kn" based on the measured data of the motor current 値In (step s2 's3). And, in the continuous operation, the heat amount obtained this time is detected 値 18 1269705
Qn是否在既定第1熱量計閩値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熱量累計閩値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 19 1269705 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 1269705 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 or not Qn is equal to or greater than the predetermined first calorimeter 闽値Qs1 (step s5), and when it is not at the first heat accumulation threshold 値Qs1 or more, the above-described processing is continued until the first heat accumulation threshold 値Qs1 is reached. Thereafter, at time t2, when the heat accumulation 値Qn obtained this time is equal to or higher than the first heat accumulation threshold 値Qs1, even in the press processing by the slider 3, the servo motor 21 is temporarily stopped in this case (step s21). ). Next, it is checked whether or not the motor current 値Is during the stop is equal to or greater than the predetermined current 値Ir (steps s22 and s23). Since the pressure is applied to the servo motor when it is higher than the allowable 値Ir, the time t2 is shown. The ascending slider 3 reaches a predetermined distance (step s24), and is temporarily stopped after the state in which the pressing torque is applied (step s6). Thereby, the load current of the servo motor 21 is reduced to a current of a desired magnitude of the slider position, and the heat accumulation 値Qn is reduced, that is, the large power semiconductor component of the servo motor 21 and the power supply circuit of the servo amplifier is drastically reduced. The temperature. In the following, the sequence from the temporary stop state to the restart is the same as the above-described step s7 to step s11, and the description thereof is omitted. According to the second embodiment, the same effect as in the first embodiment is obtained, and the heat accumulation is further exceeded. 1 In the case of the heat accumulation threshold 値Qsl, the slider is stopped immediately, and thereafter the slider is temporarily stopped at a position where the motor load current is small, and since the first heat accumulation 闽値Qsl can have only a small amount of allowable heat with respect to the overload abnormality. The servo motor 21 can be used to a maximum close to this maximum load capacity. According to the present invention, the following effects are obtained. By setting in advance a first heat accumulation threshold 对应 corresponding to a maximum motor temperature of 19 1269705 which is caused by a motor overload abnormality, corresponding to the time-weighted cumulative motor operation (including the outflow of the load current to keep the slider) At the time of the stop position, the motor load current 测 measured for each predetermined cycle time is obtained, and the heat amount 値Qn which is substantially equivalent to the motor temperature rise is obtained. The heat accumulation 値Qn obtained successively is more than the first set of the above-mentioned setting. When the heat accumulation threshold 値Qsl, the slider is temporarily stopped and the motor temperature is lowered. In the automatic operation such as the continuous operation mode of the press or the operation of the external safety one-stroke mode, the slider is temporarily stopped to reduce the motor temperature before the motor overload abnormality occurs, thereby preventing the motor overload abnormality from occurring, thereby preventing the motor overload abnormality from occurring. There is no need for a restart operation after a motor overload abnormality as shown in the prior art, and operability and workability can be improved. Further, the case where the defective product is produced due to the stoppage of the slider due to the occurrence of an overload abnormality in the working process is eliminated as in the prior art. Further, in the case where the temporary stop position of the slider is at the standby point or the top dead center of the slider, it is easy to operate in conjunction with the transfer feeder, and automatic operation can be realized. Further, since the warning information indicating "temporary stop" is displayed on the monitor display 19 during the temporary stop due to the temperature rise, the operator can easily grasp the main factor of the stop, and can be assured. BRIEF DESCRIPTION OF THE DRAWINGS (I) Schematic Part FIG. 1 is a side partial cross-sectional view of a servo press to which the present invention is applied. Figure 2 is a side partial cross-sectional view of a servo press to which the present invention is applied. Figure 3 is a block diagram of the control structure of the present invention. Fig. 4 is a control flow chart of the first embodiment. 20 1269705 Fig. 5 is a timing chart of the motor overload protection method of the first embodiment. Fig. 6 is a control flow chart of the second embodiment. Fig. 7 is a timing chart of the motor overload protection method of the second embodiment. (2) Component symbol 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 Rod 16 switching valve 19 monitor display 20 slider drive unit 21 servo motor 22a first pulley
21 1269705 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 1269705 22b 2nd pulley 23 belt 27 drive shaft 28 eccentric shaft 29 current sensor 33 position sensor 34 auxiliary frame 45 servo amplifier