201112583 六、發明說明： 【發明所屬之技術領域】 · 本發明有關於用以抑制齒槽效應轉矩（cogging • torque)之永久磁鐵式同步馬達。 【先前技術】 在永久磁鐵式同步馬達中，齒槽效應轉矩是在繞組無 通電時，當利用外部驅動使轉子磁鐵（旋轉子）旋轉時，在 定子芯子（定子鐵心）和轉子（旋轉子）之間產生之轉矩脈 動成分。轉矩漣波是當對繞組通電進行驅動之情況時，在 定子芯子和轉子（旋轉子）之間產生之轉矩脈動。 一般而言，齒槽效應轉矩是當轉子機械性旋轉一圈 時，產生定子之槽數和永久磁鐵之磁極數之最小公倍數之 脈動數。另外，該齒槽效應轉矩之大小係與脈動數成反比。 在定子安裝空心線圈，在轉子具有永久磁鐵之所謂之 無槽馬達中，未存在有定子之T形部分。因此，理論上不 會發生齒槽效應轉矩。但是，為了要固定空心線圈則變成 需要某些突起部。另一方面，透過在線圈之中心設置成為 丁形之突起部，可提升馬達之特性。 但是，當設置成為T形之突起部時，會造成齒槽效應 轉矩之發生。因此提案有在成為線圈中心之部分設置成為 T形之突起部，透過鑽研該突起部之形狀等，而提出減小 齒槽效應轉矩之技術（參照例如專利文獻1)。 (先前技術文獻） (專利文獻） 4 322188 201112583 專利文獻1 :日本特開2004-187344號公報 【發明内容】 (發明所欲解決之問題） * 但是，在先前技術中會有以下所述之問題。 * 在小直徑之馬達中，有使用定子未設T形齒之無槽構 造之情形。 在此種小直徑之馬達中，轉子之直徑亦變小，要貼裝 扇形磁鐵（單極之磁鐵）變為困難。因此，肴使用徑向異向 性環狀磁鐵或極異向性環狀磁鐵作為磁鐵之情形。 該等環狀磁鐵在1個磁鐵中具有複數個磁極數。因 此，會受到磁化磁軛形狀或製作環狀磁鐵時之影響，使各 極之磁鐵差異變大。結果，當轉子機械性旋轉一圈時，會 產生脈動數與槽數相同之齒槽效應轉矩。 由於該磁鐵差異而發生之齒槽效應轉矩，係與發生極 數和突起部數之最小公倍數之數目之該齒槽效應轉矩，在 頻率上不同。因此，單靠改良突起部之形狀，很難減小由 於磁鐵差異而發生之齒槽效應轉矩。 另外，在無槽馬達中，因為使用空心線圈，所以線圈 端部之膨大部分變大，浪費空間變多。 本發明是用來解決上述問題而研創者，其目的在提供 永久磁鐵式同步馬達，其係在設有定子突起部之無槽馬達 —-、 中，可使由於磁鐵差異所產生之齒槽效應轉矩非常接近零 之值。 (解決問題之手段） 5 322188 201112583 本發明之永久磁鐵式同步馬達，具有：定子突起部； 繞組，形成圓環狀，安裝在定子突起部；及永久磁鐵；其 中，在定子突起部間之繞組之線圈端部具有突起部。 ' (發明之效果） * 依照本發明之永久磁鐵式同步馬達，透過在線圈端部 設置與定子突起部相同數目之突起部，並有效活用未利用 空間，而在設有定子突起部之無槽馬達中，可以提供永久 磁鐵式同步馬達，使由於磁鐵差異所產生之齒槽效應轉矩 非常接近零之值。 【實施方式】 以下使用圖式來說明本發明之永久磁鐵式同步馬達之 較佳實施形態ό 另外，本發明是關於以所謂之3相電源驅動之馬達， 並具有形成圓環狀且施加有繞組（線圈）之定子突起部和永 久磁鐵之馬達。另外，本發明之技術特徵是：在此種馬達 之線圈之中心部分設有定子突起部（主極），並且在線圈中 心間之突起部和突起部之間，設有在周方向和轴方向具有 相同大小之突起部。藉由具備有此種構造，對於由於磁鐵 之極距差異、磁鐵之殘留磁通密度Br之差異、或配向差異 等與磁鐵有關之差異所產生之齒槽效應轉矩，利用作出其 反相成分來加以抵銷，而可以減小齒槽效應轉矩。換言之， 具備有突起形狀之齒槽效應轉矩減小部之點為本發明之技 術特徵。 (實施形態1) 6 322188 201112583 第1圓是用來表示本發明實施形態1之永久磁鐵式同 步馬達之垂直於軸方向之剖面的剖視圖’表示其由8極6 槽構成之一例者。第2圖是本發明實施形態1之永久磁鐵 式同步馬達之突起部分之放大圖，其顯示第1圖之突起部 la、lb之大小。另外，突起部&相當於定子突起部，突 起部lb相當於用以減小齒槽效應轉矩而設之突起部。 .第3圖至第6圖是本發明實施形態1之永久磁鐵式同 步馬達之立體圖，且為第i圖之A_A，面之軸方向之立體 圖。第3圖是表示突出部la、化之配置圖。另外，第4圖 是表不突起部la、lb之軸方向長度者。另外，第5圖是表 不在第3圖之突起部ia將要裝設線圈1〇之狀態者。另外， 第6圖是表示在該突起部la裝設線圈1〇後之狀態者。 另外，第7圖是本發明實施形態1之永久磁鐵式同步 馬達之俯視展開圖，其為在第6圖所示之該突起部la裝設 線圈10後之狀態之俯視展開圖。另外，在第丨圖中是顯示 極數為8之馬達，但是極數和槽數之组合並不只限於此種 方式。 第8圖表示本發明實施形態丨之永久磁鐵式同步馬達 之只妓子突起部la時之對旋轉角度之齒槽效應轉矩波 形、和只有突起部lb時之齒槽效應轉矩波形。 另外，本發明實施形態1之永久磁鐵式同步馬達，在 第2圖中，設W1=W2、dl=d2，突起部la和突起部lb之剖 面形狀成為相同。另外，第4圖之磁鐵之軸方向長度，如 第7圖（a)至（c)所示’係為[，突起部之長度為[卜 7 322188 201112583 (L2+L3)。但是，在第 7 圖（a)中，L>(L1+L2+L3)，在第 7 圖（b)中，L=(Ll+L2+L3)，在第 7 圖（c)中，L< (L1+L2+L3)。 依照此種方式，在L2=L3或L2#L3均不會有問題。 ’、久在形成為第1圖所示之環狀之磁鐵2〇中，檢討 磁Γ 2〇有差異之情況。當只有第3圖所示之突起部1a(定 子犬起。卩）存在之情況時，在轉子機械性地旋轉1圈之期 間’產生與槽數相同數目之轉矩脈動，亦即，產生齒槽效 應轉矩。與此相對地，就形成第5圖所示之空^線圈1〇之 情況來探討。在此種情況時，空心、線圈m部分，理想 上係形成角形形狀，以全體形狀而言，為作成長方形之ς 狀’藉，，可以用來接受更多之來自磁鐵20之磁通。 但是，在實際機器中，線圈端部具有圓弧，而成為擴 圓形之形狀。因此’在本實施形態i中，在相鄰的線圈1〇 之端部間，亦即，在線圈端部之空間，如第3圖所示，將 與突起部la相同大小之突起部lb，設在突起部之中心 之線圈端部。利用此種方式，如第8圖所示，會因突起部 lb而產生與突起部ia具有相位偏移之齒槽效應轉矩。 由突起部la產生之齒槽效應轉矩和由突起部化產生 之齒槽效應轉矩相互偏移半個週期（參照第8圖）。因此， 可以減小由於磁鐵差異所產生之齒槽效應轉矩。 依照上述方式之實施形態卜在無槽馬達中，在轴方 向之端部（亦即在線圈端部）、及於經向相鄰之突起部間之 中心位置’設置相同大小之突起部，可成為有效活用未利 用空間的構造。利用此種方式，可以形成與由於極距寬度 322188 8 201112583 之差異所產生之齒槽效應轉矩相反相位之成分，可以用來 減小齒槽效應轉矩。 (實施形態2) * 在先前之實施形態1中所說明之情況是使定子突起部 • la和突起部lb之形狀成為相同。與此相對地，在本實施 形態2中所說明之情況是使突起部lb之形狀與定子突起部 la之形狀為不同。 第9圖是用來表示本發明實施形態2之永久磁鐵式同 步馬達之垂直於軸方向之剖面的剖視圖，顯示其由8極6 槽構成之一例者。第10圖是本發明實施形態2之永久磁鐵 式同步馬達之立體圖，且為第9圖之A-A’面之軸方向之立 體圖。另外，第11圖是本發明實施形態2之永久磁鐵式同 步馬達之俯視展開圖，顯示在第9圖、第10圖之芯子裝設 有線圈10之情況之俯視展開圖。 如第10圖、第11圖所示，將突起部lb作成和突起部 la不同形狀，在相鄰之線圈端部之間之空間，以不與線圈 10接觸之方式設計突起部形狀。藉由設置此種形狀之突起 部lb，可以與上述之實施形態1同樣地，減小由於磁鐵差 異導致之齒槽效應轉矩。 第12圖表示本發明實施形態2之永久磁鐵式同步馬達 之只有定子突起部la時之對旋轉角度之齒槽效應轉矩波 形，和只有突起部lb時之齒槽效應轉矩波形，且為8極之 轉子機械性地旋轉1圈時之齒槽效應轉矩波形。突起部lb 因為與突起部la之形狀不同，所以齒槽效應轉矩波形成為 9 322188 201112583 不同之形狀。因此，使用磁場解析等模擬將 狀之大小作成最佳形狀，藉此可以在突起部h。卩lb之形 •位偏移之齒槽效應轉矩，可以減小齒槽效應產生相 •‘ 依照上述方式之實卿態2時，即使突起部1&和突起 4 lb為不同形狀，藉由使用磁場解析等模擬使突起部化 之形狀成為最佳形狀，可以獲得與前述之實施形態丨同樣 之效果。利用此種方式，即使在線圈端部之軸方向之長度 較短之形狀之馬達，藉由將設置在線圈端部之突起部作成 配合線圈形狀之形狀，可以使軸方向之長度變短，進一步 可以減小由於磁鐵差異所產生之齒槽效應轉矩。 (實施形態3) 在本實施形態3中所說明之構造是設有突起部ib，並 復具備有切削部用來減小因極數和突起部數所產生之齒槽 效應轉矩。 第13圖是用來表示本發明實施形態3之永久磁鐵式同 步馬達之垂直於軸方向之剖面的剖視圖，顯示其由8極6 槽構成之一例者。第14圖是本發明實施形態3之永久磁鐵 式同步馬達之立體圖，且為第13圖之A-A’面之抽方向之 立體圖。另外，第15圖是表示本發明實施形態3之永久磁 鐵式同步馬達之俯視展開圖。 如第13圖至第15圖所示，藉由設置突起部la ’在轉 子機械性地旋轉1圈之期間’產生成為極數和突起部數之 最小公倍數之齒槽效應轉矩。在此，因為8極，而突起部 la為6個，所以產生24個峰狀之齒槽效應轉矩。另外， 10 322188 201112583 當在磁鐵20有差異之情況時，如前述之實施形態1、2所 說明者，會產生由於磁鐵差異所導致之齒槽效應轉矩。因 此種磁鐵差異所導致的齒槽效應轉矩，係如在前述之實施 ' 形態1、2所說明，藉由在線圈端部設置突起部lb可以減 • 小0 另外，在本實施形態3中，藉由在各個突起部la之間 設置切削部2a，和在各個突起部lb之間設置切削部2b， 可以作出與因極數和突起部數而產生之齒槽效應轉矩為相 反相位之成分。第16圖表示本發明實施形態3之永久磁鐵 式同步馬達之只有突起部分時之齒槽效應轉矩波形對旋轉 角度之關係、和只有切削部分時之齒槽效應轉矩波形對旋 轉角度之關係。結果是可以減小因極數和突起部數而產生 之齒槽效應轉矩。 依照上述方式之實施形態3時，藉由復設置分別與突 .起部la、突起部lb對應之切削部2a、切削部2b，除了具 有與前述之實施形態1、2同樣之效果外，還可以減小因極 數和突起部數所產生之齒槽效應轉矩。亦即，藉由設置此 種切削部分可以更獲得使由於突起部而發生之齒槽效應轉 矩減小之效果。 (實施形態4) 在本實施形態4中所說明之情況是將前述之實施形態 1至3所說明之齒槽效應轉矩減小對策，應用在具備有極 異向性環狀磁鐵之永久磁鐵式同步馬達之情況。 第17圖是徑向環狀磁鐵21之定向圖。相對於此，第 11 322188 201112583 18圖是本發明實施形態4之永久磁鐵式同步馬達之極異向 性環狀磁鐵22之定向圖。極異向性環狀磁鐵22理論上沒 有從其定向起通過轉子芯子背部部分之磁通。因此，使用 在轉子芯子30之直徑較小，且無法取得較大轉子芯子背部 部分之馬達等。 另外，極異向性環狀磁鐵22，與徑向環狀磁鐵21不 同，從成形之定向時即決定可磁化之方向。因此，當與徑 向環狀磁鐵21比較時，各極之極距之偏移容易變大。結 果，在小直徑之馬達中，當使用極異向性環狀磁鐵22，設 置有用以安裝定子芯子之突起部la之情況時，會大幅產生 由於磁鐵之差異所導致之齒槽效應轉矩。因此，如在前述 之實施形態1至3所示，因磁鐵差異所導致之齒槽效應轉 矩之對策成為有效。 如上所述，依照實施形態4,在使用極異向性環狀磁 鐵之情況時，藉由運用前述之實施形態1至3之構造，可 以採行齒槽效應轉矩之對策。亦即，，當與徑向環狀磁鐵比 較時，極異向性環狀磁鐵其磁鐵差異等較大。但是，特別 是在小直徑之馬達，由於轉子芯子背部之影響等，所以大 多使用極異向性環狀磁鐵。因此，以在小直徑之馬達使用 極異向性環狀磁鐵之情況時之齒槽效應轉矩對策而言，前 述實施形態1至3之構造有效。 另外，在小直徑之馬達，當設置多個槽（線圈）時，所 製作之線圈之尺寸亦變小。另外，當將小尺寸之線圈設在 定子時，在製作時變為困難。因此，可以考慮選擇槽數變 12 322188 201112583 小之極槽之組合。在進行前述之實施形態1至4之齒槽效 應轉矩之對策時，藉由選擇2極3槽、4極3槽、4極6槽、 8極6槽之組合，可以使槽數變小，即使小直徑之馬達亦 可以製作。 在定量性時，具有Z個（Z為自然數）之定子突起部， 在具有2P極（P為自然數）之永久磁鐵之情況時，Z/(3(相） x2P)成為0. 5或0. 25之極槽之組合，在小直徑之馬達成為 有效。 換言之，在小直徑之馬達要求製作線圈之精確度，亦 要求施加線圈之精確度。因此，當槽（亦即線圈數）變多時 線圈之製作變為困難，且施行線圈之作業變為困難。因此， 以具有上述關係之方式規定Z和P之組合，選擇使槽數變 小之組合，可以使製作變為容易。 【圖式簡單說明】 第1圖是用來表示本發明實施形態1之永久磁鐵式同 步馬達之垂直於轴方向之剖面的剖視圖。 第2圖是本發明實施形態1之永久磁鐵式同步馬達之 突起部分之放大圖。 第3圖是本發明實施形態1之永久磁鐵式同步馬達之 立體圖。 第4圖是本發明實施形態1之永久磁鐵式同步馬達之 立體圖。 第5圖是本發明實施形態1之永久磁鐵式同步馬達之 立體圖。 13 322188 201112583 第6圖是本發明實施形態1之永久磁鐵式同步馬達之 立體圖。 第7圖（a)至（c)是本發明實施形態1之永久磁鐵式同 步馬達之俯視展開圖。 第8圖是表示本發明實施形態1之永久磁鐵式同步馬 達只有突起部la時之齒槽效應轉矩波形對旋轉角度之關 係、和只有突起部lb時之齒槽效應轉矩波形對旋轉角度之 關係的圖示。 第9圖是用來表示本發明實施形態2之永久磁鐵式同 步馬達之垂直於軸方向之剖面的剖視圖。 第10圖是本發明實施形態2之永久磁鐵式同步馬達之 立體圖。 第11圖是本發明實施形態2之永久磁鐵式同步馬達之 俯視展開圖。 第12圖表示本發明實施形態2之永久磁鐵式同步馬達 只有突起部la時之齒槽效應轉矩波形對旋轉角度之關 係、和只有突起部lb時之齒槽效應轉矩波形對旋轉角度之 關係的圖示。 第13圖是用來表示本發明實施形態3之永久磁鐵式同 步馬達之垂直於軸方向之剖面的剖視圖。 第14圖是本發明實施形態3之永久磁鐵式同步馬達之 立體圖。 第15圖是本發明實施形態3之永久磁鐵式同步馬達之 俯視展開圖。 14 322188 201112583 第16圖表示本發明實施形態3之永久磁鐵式同步馬達 只有突起部時之齒槽效應轉矩波形對旋轉角度之關係、和 只有切削部分時之齒槽效應轉矩波形對旋轉角度之關係的 圖示。 * 第17圖是徑向環狀磁鐵之定向圖。 第18圖是本發明實施形態4之永久磁鐵式同步馬達之 極性異向性環狀磁鐵之定向圖。 【主要元件符號說明】 la、lb 突起部 2a、2b 切削部 10 空心線圈 20 磁鐵 21 徑向環狀磁鐵 22 極異向性環狀磁鐵 30 轉子芯子 dl > d2 厚度 L 磁鐵之轴方向長度 LI 至 L3 突起部之長度 W1、W2 寬度 15 322188201112583 VI. Description of the Invention: [Technical Field of the Invention] The present invention relates to a permanent magnet type synchronous motor for suppressing cogging torque. [Prior Art] In the permanent magnet type synchronous motor, the cogging torque is a stator core (stator core) and a rotor (rotation) when the rotor magnet (rotator) is rotated by external driving when the winding is not energized. The torque ripple component generated between the sub). Torque chopping is the torque ripple generated between the stator core and the rotor (rotator) when the winding is energized. In general, the cogging torque is the number of pulsations that produce the least common multiple of the number of slots of the stator and the number of poles of the permanent magnet when the rotor is mechanically rotated one revolution. In addition, the magnitude of the cogging torque is inversely proportional to the number of pulsations. In the stator-mounted air-core coil, in the so-called slotless motor in which the rotor has permanent magnets, there is no T-shaped portion of the stator. Therefore, the cogging torque does not theoretically occur. However, in order to fix the air-core coil, some protrusions are required. On the other hand, by providing a protrusion formed in the center of the coil, the characteristics of the motor can be improved. However, when a T-shaped projection is provided, cogging torque is generated. Therefore, there has been proposed a technique of reducing the cogging torque by providing a projection having a T-shaped portion at the center of the coil, and by drilling the shape of the projection (see, for example, Patent Document 1). (Prior Art Document) (Patent Document) 4 322 188 201112583 Patent Document 1: JP-A-2004-187344 SUMMARY OF INVENTION (Problems to be Solved by the Invention) * However, there are problems in the prior art as described below. . * In the small-diameter motor, there is a case where the stator has no groove-shaped structure without T-shaped teeth. In such a small-diameter motor, the diameter of the rotor also becomes small, and it becomes difficult to mount a sector magnet (a magnet of a single pole). Therefore, the case of using a radially anisotropic annular magnet or an extremely anisotropic annular magnet as a magnet is used. The ring magnets have a plurality of magnetic pole numbers in one magnet. Therefore, it is affected by the shape of the magnetized yoke or the shape of the ring magnet, and the difference in the magnets of the respective poles is increased. As a result, when the rotor is mechanically rotated one turn, cogging torque having the same number of pulsations as the number of slots is generated. The cogging torque which occurs due to the difference in the magnet is different from the cogging torque which is the number of the smallest common multiple of the number of the poles and the number of the projections. Therefore, it is difficult to reduce the cogging torque which occurs due to the difference in the magnets by merely improving the shape of the projections. Further, in the slotless motor, since the air-core coil is used, most of the expansion of the coil end portion is large, and the wasted space is increased. SUMMARY OF THE INVENTION The present invention has been made in an effort to solve the above problems, and an object thereof is to provide a permanent magnet type synchronous motor which is provided in a slotless motor provided with a stator protrusion, which can cause a cogging effect due to a difference in magnets. The torque is very close to zero. (Means for Solving the Problem) 5 322188 201112583 The permanent magnet synchronous motor of the present invention has: a stator protrusion; a winding formed in an annular shape and mounted on the stator protrusion; and a permanent magnet; wherein the winding between the stator protrusions The coil end has a protrusion. (Effect of the Invention) * According to the permanent magnet type synchronous motor of the present invention, the same number of projections as the stator projections are provided at the end portions of the coil, and the unused space is effectively utilized, and the slot is provided without the slots of the stator protrusions. In the motor, a permanent magnet type synchronous motor can be provided so that the cogging torque due to the difference in the magnet is very close to zero. [Embodiment] Hereinafter, a preferred embodiment of a permanent magnet type synchronous motor of the present invention will be described using a drawing. In addition, the present invention relates to a motor driven by a so-called 3-phase power source, and has an annular shape and a winding applied thereto. The stator of the (coil) and the motor of the permanent magnet. Further, the technical feature of the present invention is that a stator protrusion (main pole) is provided at a central portion of a coil of such a motor, and a circumferential direction and an axial direction are provided between the protrusion between the center of the coil and the protrusion. A protrusion having the same size. By having such a configuration, the cogging torque generated by the difference in the magnetism due to the difference in the pole pitch of the magnet, the difference in the residual magnetic flux density Br of the magnet, or the difference in the alignment is utilized. To offset, the cogging torque can be reduced. In other words, the point of having the cogging torque reducing portion having the protruding shape is a technical feature of the present invention. (Embodiment 1) 6 322188 201112583 The first circle is a cross-sectional view showing a cross section perpendicular to the axial direction of the permanent magnet type synchronous motor according to the first embodiment of the present invention, which is an example of an 8-pole 6-slot. Fig. 2 is an enlarged view of a projection portion of the permanent magnet type synchronous motor according to the first embodiment of the present invention, showing the size of the projections la and lb of Fig. 1. Further, the projections & corresponds to the stator projections, and the projections lb correspond to the projections provided to reduce the cogging torque. Fig. 3 through Fig. 6 are perspective views of the permanent magnet type synchronous motor according to the first embodiment of the present invention, and are a perspective view of the axis direction of the plane A_A of Fig. Fig. 3 is a layout view showing the protruding portion la. Further, Fig. 4 shows the length in the axial direction of the projections 1a and 1b. Further, Fig. 5 is a view showing a state in which the coil 1 is to be mounted on the projection ia of Fig. 3. In addition, Fig. 6 is a view showing a state in which the coil 1 is attached to the projection 1a. In addition, Fig. 7 is a plan view showing a state in which the coil 10 is attached to the projection 1a shown in Fig. 6 in a plan view of the permanent magnet type synchronous motor according to the first embodiment of the present invention. In addition, in the figure, a motor having a number of poles of 8 is shown, but the combination of the number of poles and the number of slots is not limited to this. Fig. 8 is a view showing the cogging torque waveform of the rotational angle of the permanent magnet type synchronous motor of the permanent magnet type synchronous motor according to the embodiment of the present invention, and the cogging torque waveform when only the projection lb is formed. Further, in the permanent magnet type synchronous motor according to the first embodiment of the present invention, in the second drawing, W1 = W2 and dl = d2, and the cross-sectional shapes of the projections 1a and 1b are the same. Further, the axial length of the magnet of Fig. 4 is as shown in Fig. 7 (a) to (c), and the length of the projection is [Bu 7 322188 201112583 (L2+L3). However, in Fig. 7(a), L > (L1 + L2 + L3), in Fig. 7 (b), L = (Ll + L2 + L3), in Fig. 7 (c), L <; (L1+L2+L3). In this way, there is no problem in L2=L3 or L2#L3. In the case of the ring magnet 2〇 shown in Fig. 1, it is considered that there is a difference in the magnetic Γ2〇. When only the projection 1a (the stator dog 卩) shown in Fig. 3 exists, the same number of torque pulsations as the number of slots are generated during the period in which the rotor is mechanically rotated one turn, that is, the teeth are generated. Slot torque. On the other hand, the case where the air coil 1 shown in Fig. 5 is formed is discussed. In this case, the hollow portion and the m portion of the coil are desirably formed into an angular shape, and in the overall shape, a rectangular shape can be used to receive more magnetic flux from the magnet 20. However, in an actual machine, the end portion of the coil has an arc shape and becomes an expanded circular shape. Therefore, in the present embodiment i, between the end portions of the adjacent coils 1A, that is, in the space at the end portions of the coils, as shown in Fig. 3, the protrusions lb having the same size as the protrusions 1a are formed. The coil end portion is provided at the center of the protrusion. In this manner, as shown in Fig. 8, the cogging torque having a phase shift from the projection ia is generated by the projection lb. The cogging torque generated by the projection 1a and the cogging torque generated by the projection are shifted by half a cycle (see Fig. 8). Therefore, the cogging torque due to the difference in the magnet can be reduced. According to the embodiment of the above aspect, in the slotless motor, the projections of the same size are provided at the end portions in the axial direction (that is, at the end portions of the coils) and at the center positions between the adjacent projections. It becomes a structure that effectively uses unused space. In this way, a component that is opposite in phase to the cogging torque due to the difference in pole width 322188 8 201112583 can be formed, which can be used to reduce the cogging torque. (Embodiment 2) * In the case of the first embodiment, the shape of the stator protrusion portion la and the protrusion portion lb are the same. On the other hand, in the second embodiment, the shape of the projection lb is different from the shape of the stator projection la. Fig. 9 is a cross-sectional view showing a cross section perpendicular to the axial direction of the permanent magnet type synchronous motor according to the second embodiment of the present invention, showing an example in which it is composed of eight poles and six slots. Fig. 10 is a perspective view of the permanent magnet type synchronous motor according to the second embodiment of the present invention, and is a perspective view of the axis direction of the A-A' plane of Fig. 9. In addition, Fig. 11 is a plan view showing a plan view of a permanent magnet type synchronous motor according to a second embodiment of the present invention, and showing a state in which the core 10 of the ninth and tenth drawings is provided with a coil 10. As shown in Figs. 10 and 11, the projections 1b are formed in different shapes from the projections la, and the projections are designed so as not to be in contact with the coils 10 in the space between the adjacent coil ends. By providing the projections 1b of such a shape, the cogging torque due to the difference in the magnet can be reduced in the same manner as in the first embodiment described above. Fig. 12 is a view showing a cogging torque waveform of a pair of rotation angles when only the stator projections 1a of the permanent magnet synchronous motor according to the second embodiment of the present invention, and a cogging torque waveform when only the projection lb is present, and The cogging torque waveform when the 8-pole rotor is mechanically rotated one revolution. Since the protrusion lb is different from the shape of the protrusion 1a, the cogging torque waveform has a different shape of 9 322188 201112583. Therefore, the size of the shape can be made into an optimum shape by using a magnetic field analysis or the like, whereby the protrusion h can be formed.卩 lb shape • The cogging torque of the bit offset can reduce the cogging effect to produce a phase. 'When the solid state 2 is obtained according to the above method, even if the protrusion 1& and the protrusion 4 lb are different shapes, The shape of the protrusion is optimized by simulation such as magnetic field analysis, and the same effects as those of the above-described embodiment can be obtained. According to this aspect, even in a motor having a shape in which the length of the coil end portion in the axial direction is short, the length of the axial direction can be shortened by forming the protruding portion provided at the end portion of the coil into a shape of a coil shape, and further The cogging torque due to the difference in the magnet can be reduced. (Embodiment 3) The structure described in the third embodiment is provided with a projection ib and a cutting portion for reducing the cogging torque due to the number of poles and the number of projections. Fig. 13 is a cross-sectional view showing a cross section perpendicular to the axial direction of the permanent magnet type synchronous motor according to the third embodiment of the present invention, showing an example in which it is composed of eight poles and six slots. Fig. 14 is a perspective view of the permanent magnet type synchronous motor according to the third embodiment of the present invention, and is a perspective view of the drawing direction of the A-A' plane of Fig. 13. Fig. 15 is a plan development view showing a permanent magnet synchronous motor according to a third embodiment of the present invention. As shown in Figs. 13 to 15, the cogging torque which is the least common multiple of the number of poles and the number of projections is generated by the provision of the projections la' during the period in which the rotor is mechanically rotated by one revolution. Here, since the eight poles and the projections la are six, 24 peak-shaped cogging torques are generated. Further, 10 322 188 201112583 When there is a difference in the magnets 20, as described in the first and second embodiments, the cogging torque due to the difference in the magnets may occur. Therefore, the cogging torque caused by the difference in the types of the magnets can be reduced or decreased by providing the projections 1b at the end portions of the coils as described in the above-described embodiments 1 and 2, and in the third embodiment, By providing the cutting portion 2a between the respective protrusions 1a and the cutting portion 2b between the respective protrusions 1b, it is possible to make the opposite phase to the cogging torque due to the number of poles and the number of protrusions. ingredient. Fig. 16 is a view showing the relationship between the cogging torque waveform of the permanent magnet type synchronous motor of the third embodiment of the present invention and the cogging torque waveform when the cutting portion is only the projection portion, and the rotation angle. . As a result, the cogging torque due to the number of poles and the number of projections can be reduced. According to the third embodiment, the cutting portion 2a and the cutting portion 2b corresponding to the protruding portion 1a and the protruding portion 1b are provided in addition to the effects similar to those of the first and second embodiments described above. The cogging torque due to the number of poles and the number of protrusions can be reduced. Namely, by providing such a cutting portion, the effect of reducing the cogging torque due to the projection can be more obtained. (Embodiment 4) In the case of the fourth embodiment, the cogging torque reduction measures described in the first to third embodiments are applied to a permanent magnet having an anisotropic annular magnet. The case of a synchronous motor. Figure 17 is an orientation view of the radial ring magnet 21. On the other hand, the 11th 322188, 201112583 18 is an orientation view of the anisotropic annular magnet 22 of the permanent magnet type synchronous motor according to the fourth embodiment of the present invention. The extremely anisotropic annular magnet 22 is theoretically free of magnetic flux passing through the back portion of the rotor core from its orientation. Therefore, a motor or the like in which the diameter of the rotor core 30 is small and the back portion of the larger rotor core cannot be obtained is used. Further, the extremely anisotropic annular magnet 22 is different from the radial annular magnet 21, and the direction of magnetization is determined from the orientation of the forming. Therefore, when compared with the radial ring magnet 21, the offset of the pole pitch of each pole tends to become large. As a result, in the case of the small-diameter motor, when the extremely anisotropic annular magnet 22 is used and the protrusions la for mounting the stator core are provided, the cogging torque due to the difference of the magnets is greatly generated. . Therefore, as shown in the first to third embodiments described above, the countermeasure against the cogging torque due to the difference in the magnet is effective. As described above, according to the fourth embodiment, when the extremely anisotropic annular magnet is used, the countermeasures of the cogging torque can be obtained by applying the structures of the first to third embodiments described above. That is, when compared with a radial ring-shaped magnet, the extremely anisotropic annular magnet has a large difference in magnets and the like. However, especially in small-diameter motors, extremely anisotropic annular magnets are used due to the influence of the back of the rotor core. Therefore, the configuration of the first to third embodiments is effective in the case of the cogging torque in the case of using a very anisotropic annular magnet for a motor having a small diameter. Further, in a small-diameter motor, when a plurality of grooves (coils) are provided, the size of the coil to be produced is also small. Further, when a small-sized coil is provided in the stator, it becomes difficult at the time of production. Therefore, consider the combination of the number of slots 12 322188 201112583 small pole slots. When the cogging torque of the first to fourth embodiments is carried out, the number of slots can be made small by selecting a combination of two poles, three slots, four poles, three slots, four poles, six slots, and eight poles and six slots. Even small diameter motors can be made. In the case of a permanent magnet having a 2P pole (P is a natural number), Z/(3(phase) x2P) becomes 0.5 or 5 The combination of the 0. 25 pole slots is effective in small diameter motors. In other words, the precision of the coil is required for a small diameter motor, and the accuracy of the coil is also required. Therefore, when the number of grooves (i.e., the number of coils) is increased, the production of the coil becomes difficult, and the operation of applying the coil becomes difficult. Therefore, by combining the combination of Z and P in such a manner as described above, it is possible to make the production easier by selecting a combination in which the number of slots is reduced. [Brief Description of the Drawings] Fig. 1 is a cross-sectional view showing a cross section perpendicular to the axial direction of the permanent magnet type synchronous motor according to the first embodiment of the present invention. Fig. 2 is an enlarged view showing a projection portion of the permanent magnet type synchronous motor according to the first embodiment of the present invention. Fig. 3 is a perspective view showing a permanent magnet type synchronous motor according to the first embodiment of the present invention. Fig. 4 is a perspective view showing a permanent magnet type synchronous motor according to the first embodiment of the present invention. Fig. 5 is a perspective view showing a permanent magnet type synchronous motor according to the first embodiment of the present invention. 13 322 188 201112583 Fig. 6 is a perspective view of the permanent magnet type synchronous motor according to the first embodiment of the present invention. Fig. 7 (a) to (c) are plan development views of the permanent magnet type synchronous motor according to the first embodiment of the present invention. Fig. 8 is a view showing the relationship between the cogging torque waveform versus the rotation angle when the permanent magnet type synchronous motor according to the first embodiment of the present invention has only the projection portion la, and the cogging torque waveform versus the rotation angle when only the projection lb is present. An illustration of the relationship. Fig. 9 is a cross-sectional view showing a cross section perpendicular to the axial direction of the permanent magnet type synchronous motor according to the second embodiment of the present invention. Figure 10 is a perspective view of a permanent magnet type synchronous motor according to a second embodiment of the present invention. Figure 11 is a plan view showing the development of a permanent magnet type synchronous motor according to a second embodiment of the present invention. Fig. 12 is a view showing the relationship between the cogging torque waveform versus the rotation angle when the permanent magnet type synchronous motor according to the second embodiment of the present invention has only the projection portion la, and the cogging torque waveform when the projection portion 1b is only used. An illustration of the relationship. Fig. 13 is a cross-sectional view showing a cross section perpendicular to the axial direction of the permanent magnet type synchronous motor according to the third embodiment of the present invention. Fig. 14 is a perspective view showing a permanent magnet type synchronous motor according to a third embodiment of the present invention. Figure 15 is a plan view showing the development of a permanent magnet type synchronous motor according to a third embodiment of the present invention. 14 322188 201112583 Fig. 16 is a view showing the relationship between the cogging torque waveform of the permanent magnet type synchronous motor of the third embodiment of the present invention and the cogging torque waveform when only the cutting portion is used, and the rotation angle of the cogging torque waveform. An illustration of the relationship. * Figure 17 is an orientation diagram of a radial ring magnet. Figure 18 is a perspective view showing a polar anisotropic annular magnet of a permanent magnet type synchronous motor according to a fourth embodiment of the present invention. [Description of main component symbols] la, lb protrusions 2a, 2b cutting part 10 air-core coil 20 magnet 21 radial ring magnet 22 pole anisotropic ring magnet 30 rotor core dl > d2 thickness L axis length of the magnet LI to L3 The length of the protrusion W1, W2 Width 15 322188