TWI609554B

TWI609554B - Electrical rotating machine

Info

Publication number: TWI609554B
Application number: TW105129979A
Authority: TW
Inventors: 小林孝幸
Original assignee: 山葉發動機股份有限公司
Priority date: 2015-09-16
Filing date: 2016-09-14
Publication date: 2017-12-21
Also published as: TW201725830A; JP2017060395A; JP6761310B2

Description

Rotating electric machine and stator

本發明係關於一種定子及具備該定子之旋轉電機。The present invention relates to a stator and a rotating electrical machine including the same.

自先前以來，為了使機器驅動而使用作為旋轉電機之馬達。例如，作為馬達之構成已知有如下構成，即，具備：定子，其具有定子芯及定子線圈；及轉子，其具有轉子芯及磁鐵。於具有此種構成之馬達中，定子芯具有圓筒狀之磁軛、及自該磁軛之內周面或外周面沿該磁軛之徑向延伸之複數個齒部。具有上述構成之馬達於上述齒部捲繞有定子線圈。近年來，為了於不使馬達大型化之情況下增大藉由馬達驅動之機器之輸出，有欲提高馬達之輸出扭矩之要求。為了提高具有如上述之構成之馬達之輸出扭矩而有如下方法，即，增多定子線圈之匝數或增大轉子之磁鐵之磁通密度。於增多定子線圈之匝數之情形時考慮如下構成，即，以分別包含一個齒部之方式將定子芯之磁軛於圓周方向分割為複數個零件。例如，如專利文獻1所揭示般已知有如下馬達，即，定子芯由在圓周方向上分割之複數個分割芯構成，並且該分割芯之磁軛抵接於鄰接之分割芯之磁軛。如上述專利文獻1所揭示般，藉由利用複數個分割芯構成定子芯，可容易地將定子線圈捲繞於分割芯之各齒部。藉此，可於使用繞組噴嘴將定子線圈捲繞於各齒部之後，將分別捲繞有該定子線圈之複數個分割芯於以磁軛彼此抵接之方式配置之狀態連結。如此一來，與定子芯為圓環狀之情形相比，可擴大於分割芯之齒部捲繞定子線圈時齒部之前端彼此之間隔。因此，可增加捲繞於齒部之定子線圈之匝數，因此，定子線圈之槽滿率增加。由此，可提高馬達之效率。 [先前技術文獻] [專利文獻] [專利文獻1]日本專利特開2011-19360號公報Since the beginning, a motor as a rotary electric machine has been used in order to drive the machine. For example, as a configuration of a motor, a stator including a stator core and a stator coil, and a rotor having a rotor core and a magnet are known. In the motor having such a configuration, the stator core has a cylindrical yoke and a plurality of teeth extending from the inner circumferential surface or the outer circumferential surface of the yoke in the radial direction of the yoke. The motor having the above configuration has a stator coil wound around the tooth portion. In recent years, in order to increase the output of a machine driven by a motor without increasing the size of the motor, there is a demand for an increase in the output torque of the motor. In order to increase the output torque of the motor having the above configuration, there is a method of increasing the number of turns of the stator coil or increasing the magnetic flux density of the magnet of the rotor. In the case where the number of turns of the stator coil is increased, a configuration is considered in which the yoke of the stator core is divided into a plurality of parts in the circumferential direction so as to include one tooth portion. For example, as disclosed in Patent Document 1, there is known a motor in which a stator core is composed of a plurality of divided cores divided in the circumferential direction, and a yoke of the split core abuts against a yoke of an adjacent split core. As disclosed in Patent Document 1, the stator core can be easily wound around the respective tooth portions of the split core by forming the stator core by a plurality of split cores. Thereby, after the stator coil is wound around each tooth portion by using the winding nozzle, a plurality of split cores each of which is wound around the stator coil are connected in a state in which the yokes are placed in contact with each other. In this way, compared with the case where the stator core is annular, the distance between the front ends of the teeth portions when the stator coils of the split core are wound around the stator coil can be expanded. Therefore, the number of turns of the stator coil wound around the tooth portion can be increased, and therefore, the slot full rate of the stator coil is increased. Thereby, the efficiency of the motor can be improved. [Prior Art Document] [Patent Document] [Patent Document 1] Japanese Patent Laid-Open Publication No. 2011-19360

[發明所欲解決之問題] 然而，於如專利文獻1所揭示般藉由複數個零件構成定子芯之磁軛之情形時，相鄰之零件之接觸面分別為平面。一般而言，難以使平面彼此以不產生間隙之方式接觸。因此，於以構成磁軛之方式相鄰之零件之接觸部分產生間隙。藉由該間隙而磁軛之磁阻變大。因此，即便於如專利文獻1所揭示之構成般，可藉由利用複數個零件構成定子芯之磁軛而使定子線圈之相對於齒部之匝數增加之情形時，於定子產生之磁通密度亦不會變太大。因此，無法提高馬達之輸出扭矩。另一方面，為了增大於定子產生之磁通密度，較佳為抑制磁軛之磁阻之增大。因此，較佳為並非藉由如上述之複數個零件構成磁軛，而係一體地構成磁軛。然而，若如此般一體地構成磁軛，則無法增加捲繞於齒部之定子線圈之匝數。如上所述，為了增大定子之磁通密度，難以兼顧增加定子線圈之匝數、及抑制定子芯之磁阻之增大。因此，本發明之目的在於獲得一種能夠兼顧增加定子線圈之匝數與抑制定子芯之磁阻之增大之旋轉電機。 [解決問題之技術手段] 於如專利文獻1所揭示般，藉由複數個零件構成定子芯之磁軛之情形時，相鄰之零件之平面與平面面接觸。因此，於相鄰之零件之接觸部分產生間隙。對此，藉由於構成磁軛之零件之接觸面分別設置凹凸，可增加上述零件彼此之接觸點之個數。如此，於上述零件彼此之接觸部分產生之間隙減少，因此，可增大於定子芯產生之磁通密度。本發明者們為了於構成磁軛之零件之接觸面設置凹凸，而著眼於使用包含磁性材料之粒子之粉粒體之鐵粉心。由於鐵粉心為包含磁性材料之粒子之粉粒體之集合體，故而於使鐵粉心斷裂時，斷裂沿著粒子與粒子之交界進展。因此，容易於斷裂面形成凹凸。本發明者們著眼於使用包含磁性材料之粒子之粉粒體之鐵粉心之如上所述之特性而想到如下構成。本發明之一實施形態之旋轉電機係具備定子之旋轉電機。上述定子具有：定子芯，其包括圓筒狀之磁軛、及自該磁軛之內周面或外周面朝向該磁軛之徑向延伸之複數個齒部；及定子線圈，其捲繞於上述齒部。上述定子芯係使用包含磁性材料之粒子之粉粒體之鐵粉心，且具備於上述磁軛之圓周方向具有斷裂面之複數個磁軛片。上述齒部係分別設置一個於具有上述斷裂面之上述複數個磁軛片中之至少一部分磁軛片。具有上述斷裂面之上述複數個磁軛片中之相鄰之磁軛片係上述斷裂面與相鄰之磁軛片之上述斷裂面接觸。 [發明之效果] 根據本發明之一實施形態之旋轉電機，可謀求兼顧增加定子線圈之匝數與抑制定子芯之磁阻之增大。[Problems to be Solved by the Invention] However, in the case where the yoke of the stator core is constituted by a plurality of parts as disclosed in Patent Document 1, the contact faces of the adjacent parts are respectively flat. In general, it is difficult to make the planes in contact with each other without creating a gap. Therefore, a gap is generated in the contact portion of the member adjacent to each other in such a manner as to constitute the yoke. The magnetic resistance of the yoke is increased by the gap. Therefore, even in the case of the configuration disclosed in Patent Document 1, the magnetic flux generated in the stator can be increased by constituting the yoke of the stator core with a plurality of parts to increase the number of turns of the stator coil with respect to the tooth portion. The density will not become too great. Therefore, the output torque of the motor cannot be increased. On the other hand, in order to increase the magnetic flux density generated in the stator, it is preferable to suppress an increase in the magnetic resistance of the yoke. Therefore, it is preferable that the yoke is integrally formed without forming the yoke by a plurality of parts as described above. However, if the yoke is integrally formed in this manner, the number of turns of the stator coil wound around the tooth portion cannot be increased. As described above, in order to increase the magnetic flux density of the stator, it is difficult to achieve both an increase in the number of turns of the stator coil and an increase in the magnetic resistance of the stator core. Accordingly, it is an object of the present invention to obtain a rotary electric machine capable of achieving both an increase in the number of turns of the stator coil and an increase in the magnetic resistance of the stator core. [Technical means for solving the problem] As in the case of the yoke of the stator core formed by a plurality of parts as disclosed in Patent Document 1, the plane of the adjacent parts is in contact with the plane surface. Therefore, a gap is generated at the contact portion of the adjacent part. On the other hand, by providing irregularities on the contact faces of the components constituting the yoke, the number of contact points between the above components can be increased. Thus, the gap generated in the contact portion between the above-mentioned parts is reduced, and therefore, the magnetic flux density generated in the stator core can be increased. In order to provide irregularities on the contact faces of the components constituting the yoke, the inventors focused on the use of iron powder cores containing powder particles of magnetic material. Since the iron powder core is a collection of powder or granules containing particles of a magnetic material, when the iron powder core is broken, the fracture progresses along the boundary between the particles and the particles. Therefore, it is easy to form irregularities on the fracture surface. The inventors of the present invention have conceived the following configuration by focusing on the above-described characteristics of the iron powder core of the powder or granule containing the particles of the magnetic material. A rotary electric machine according to an embodiment of the present invention includes a rotating electric machine of a stator. The stator includes: a stator core including a cylindrical yoke; and a plurality of teeth extending from an inner circumferential surface or an outer circumferential surface of the yoke toward a radial direction of the yoke; and a stator coil wound around The above tooth portion. The stator core is made of a powder core including powder particles of a magnetic material, and a plurality of yoke sheets having a fracture surface in the circumferential direction of the yoke. The tooth portions are each provided with at least a part of the plurality of yoke sheets having the fracture surface. The adjacent yoke sheets of the plurality of yoke sheets having the fracture surface are in contact with the fracture surface of the adjacent yoke sheets. [Effects of the Invention] According to the rotary electric machine according to the embodiment of the present invention, it is possible to increase the number of turns of the stator coil and suppress the increase in the magnetic resistance of the stator core.

以下，一面參照圖式一面對各實施形態進行說明。再者，各圖中之構成構件之尺寸並非忠實地表示實際之構成構件之尺寸及各構成構件之尺寸比率等。＜馬達之整體構成＞圖1係表示本發明之實施形態之馬達1(旋轉電機)之整體構成之立體圖。該馬達1具備圓筒狀之定子2、及以旋轉中心與該定子2之軸線P一致之方式配置於該定子2之內側之圓筒狀之轉子3。即，馬達1整體形成為圓筒狀。馬達1例如用於用以輔助電動自行車之踏板踏力之馬達等。再者，於圖1中，符號P表示沿著定子2之筒軸方向延伸之軸線。定子2具備形成為圓筒狀之定子芯11、及捲繞於該定子芯11之定子線圈12。定子芯11係包含含有磁性材料之粒子之粉粒體之鐵粉心。即，定子芯11係藉由使用成形模具以特定之壓力將粉粒體固定而一體成形。圖2表示定子芯11之具體之構成。該圖2係自定子2之軸線方向觀察定子芯11之前視圖。如圖2所示，定子芯11具備磁軛21、及複數個齒部22。於本實施形態中，定子芯11具有12個齒部22。磁軛21形成為圓筒狀。各齒部22自磁軛21之內周面朝向該磁軛21之內側延伸。複數個齒部22於磁軛21之內周面上，自定子2之軸線方向觀察係於圓周方向上等間隔地排列而形成。如圖1及圖2所示，定子芯11之圓筒狀之磁軛21於圓周方向上斷裂分割為複數個。即，定子芯11具有藉由斷裂分割而形成之複數個磁軛片21a。定子芯11以各磁軛片21a分別包含一個齒部22之方式斷裂分割。因此，定子芯11斷裂分割為與齒部22相同數量之磁軛片21a。於本實施形態之情形時，定子芯11以各磁軛片21a包含齒部22之方式於圓周方向上分割為12個。以下對定子芯11之斷裂分割之詳情進行敍述。齒部22自定子2之軸線方向觀察形成為大致T字狀。即，齒部22具有：齒部本體部22a，其自磁軛21之內周面朝向該磁軛21之內側延伸；及齒部前端部22b，其位於較該齒部本體部22a更靠齒部22之前端側。齒部22與轉子3對向。齒部前端部22b較齒部本體部22a更靠近轉子3。齒部本體部22a形成為自磁軛21之內周面朝向該磁軛21之內側延伸之四稜柱狀。於齒部本體部22a中，於沿齒部22之延伸方向延伸之側面之角部分形成有R部22c。R部22c可形成於齒部22之上述側面之所有角部分，亦可形成於一部分之角部分。即，如圖3所示，齒部本體部22a於與齒部22之延伸方向正交之剖面，於至少一部分具有朝向齒部本體部22a之外側呈凸狀之R部22c。再者，齒部22之延伸方向與定子芯11(磁軛21)之徑向相同。如圖1所示，於齒部本體部22a捲繞有定子線圈12。藉由如上所述般於齒部本體部22a之側面設置R部22c，可防止捲繞於該齒部本體部22a之定子線圈12受損傷。再者，R部22c亦可為倒角。如圖3所示，齒部本體部22a於定子2之軸線方向上以齒部本體部22a之端部位於較磁軛21之端部更靠馬達1之內側之方式形成。即，齒部本體部22a之上述軸線方向之長度較磁軛21之上述軸線方向之長度短。藉此，可防止於在齒部本體部22a捲繞有定子線圈12之狀態下，於定子2之軸線方向上定子線圈12向較磁軛21更靠定子2之外側突出。如圖3所示，齒部前端部22b之寬度方向尺寸(自軸線方向觀察定子2時之圓周方向之尺寸)及上述軸線方向之尺寸，大於齒部本體部22a之寬度方向尺寸及上述軸線方向之尺寸。即，齒部前端部22b相對於齒部本體部22a於上述寬度方向及上述軸線方向突出。藉由此種齒部前端部22b之構成，可防止捲繞於齒部本體部22a之定子線圈12自齒部22之前端脫落。因此，可相對於齒部本體部22a更確實地捲繞定子線圈12。又，藉由如上所述之齒部前端部22b之構成，於藉由捲繞於齒部本體部22a之定子線圈12而產生磁場時，可於齒部前端部22b之周邊大範圍地形成較強之磁場。雖未特別圖示，但藉由定子芯11之斷裂分割而獲得之複數個磁軛片21a於以構成原本之定子芯11之方式組合之狀態下藉由保持構件等保持。該保持構件可為用以保持複數個磁軛片21a之專用之構件，亦可由收納馬達1之殼體構成。如圖1所示，轉子3形成為圓筒狀，且以旋轉中心與該定子2之軸線P一致之方式配置於定子2之內側。雖未特別圖示，但轉子3以能夠與旋轉軸一體旋轉之方式於該旋轉軸貫通之狀態固定於該旋轉軸。轉子3具備轉子芯31、及場磁鐵32。轉子芯31係包含磁性材料之圓筒狀之構件。於轉子芯31之外周面形成有用以配置場磁鐵32之複數個狹縫31a。各狹縫31a係具有如下深度之凹部，即，於在狹縫31a內配置有場磁鐵32之狀態下，該場磁鐵32之一部分露出。於本實施形態中，如圖1所示，於轉子芯31之外周面，於14部位形成有狹縫31a。又，各狹縫31a於轉子芯31之軸線方向上自轉子芯31之一端部遍及至另一端部而形成於轉子芯31之外周面。場磁鐵32為永久磁鐵，且形成為長方體狀。場磁鐵32以壁厚方向之一部分露出之狀態固定於形成於轉子芯31之外周面之狹縫31a內。 (定子芯之斷裂分割) 使用圖2至圖4對定子芯11之磁軛21之斷裂分割詳細地進行說明。圖3係表示將定子芯11之磁軛21斷裂分割而獲得之磁軛片21a之概略構成之立體圖。圖4係模式性地表示於對定子線圈12通電而產生磁場時於磁軛21產生之磁通之方向之圖。定子芯11之磁軛21於圓周方向斷裂分割為複數個。藉由如此將磁軛21於圓周方向斷裂分割為複數個而形成複數個磁軛片21a。磁軛片21a具有藉由將磁軛21分割而獲得之分割部21c、及齒部22。磁軛21以各磁軛片21a分別包含一個齒部22之方式被斷裂分割。藉由以此方式分割定子芯11，而於相對於齒部22捲繞定子線圈12時，不會受到相鄰之齒部22之影響。由此，可於磁軛片21a之齒部22容易地捲繞定子線圈12，並且可增多捲繞於齒部22之定子線圈12之匝數。磁軛片21a之分割部21c係藉由將圓筒狀之磁軛21於圓周方向上斷裂分割而獲得。因此，分割部21c自定子2之軸線方向觀察形成為圓弧狀。分割部21c自上述軸線方向觀察於圓周方向之兩端具有斷裂面21b。即，磁軛片21a於磁軛21之圓周方向具有斷裂面21b。斷裂面21b係藉由以自上述軸線方向觀察磁軛21於該磁軛21之徑向延伸之方式將該磁軛21斷裂分割而形成。藉由對捲繞於齒部22之定子線圈12通電，而於磁軛21自齒部22於磁軛21之圓周方向形成磁通(參照圖4)。由此，如圖4所示，自上述軸線方向觀察磁軛21，斷裂面21b於相對於當對定子線圈12通電而產生磁場之情形時於磁軛21產生之磁通之方向(圖4中之虛線箭頭)正交的方向延伸。藉由形成如上述之構成之斷裂面21b，而與自上述軸線方向觀察磁軛21，斷裂面21b於相對於在磁軛21產生之磁通之方向而傾斜交叉之方向延伸之情形相比，斷裂面21b之面積較小。藉此，與斷裂面於相對於磁通之方向傾斜交叉之方向延伸之情形相比，自斷裂面21b脫落微細之缺損片之可能性變低。由此，藉由本實施形態之構成，可降低因缺損片之脫落而於斷裂面21b與斷裂面21b之間形成間隙之可能性。因此，可更確實地抑制磁軛21之磁阻之增大。又，於斷裂面於相對於在磁軛產生之磁通之方向而傾斜交叉之方向延伸之情形時，於磁軛片之斷裂部分，磁軛片之徑向之壁厚於磁軛之圓周方向不同。相對於此，藉由如本實施形態之構成般，以於相對於在磁軛21產生之磁通之方向而正交之方向延伸的方式形成斷裂面21b，可使磁軛片21a之於圓周方向之上述壁厚均等。由此，可抑制磁軛片21a之強度降低。於本實施形態中，所謂自上述軸線方向觀察磁軛21，斷裂面21b於相對於磁通之方向而正交之方向延伸，並不限於斷裂面21b相對於磁通的方向呈直角相交之情形，亦包含於包含直角之特定之角度範圍(例如自80度至100度之範圍)相交之情形。如上所述，由於定子芯11係包含含有磁性材料之粒子之粉粒體之鐵粉心，故而於將該定子芯11斷裂分割之情形時，該定子芯11沿著粒子與粒子之交界斷裂。由此，磁軛片21a之斷裂面21b具有多數個凹凸。因此，於在將磁軛21斷裂分割而形成磁軛片21a之後以恢復原來形狀之磁軛21之方式將磁軛片21a的斷裂面21b彼此組合之情形時，可使形成於斷裂面21b之凹凸彼此嚙合。藉此，不易於磁軛片21a之斷裂面21b彼此之間形成空間。此處，所謂斷裂分割意指藉由對磁軛21施加力而將該磁軛21脆性破壞。即，所謂斷裂分割意指將作為鐵粉心之定子芯11之磁軛21以沿著構成鐵粉心的粒子與粒子之交界斷裂之方式脆性破壞。因此，於將磁軛21斷裂分割時形成之斷裂面21b形成多數個凹凸。藉此，斷裂面21b具有梨皮狀之表面。再者，所謂斷裂面21b意指於作為鐵粉心之定子芯11之磁軛21當粒子失去凝聚力而被破壞時所形成之面。如先前之構成般，於藉由機械加工等而形成磁軛片之情形時，由於磁軛片彼此以平面接觸，故而容易於接觸部分產生間隙。因此，磁軛被分割之情形之該磁軛之磁阻與一體之磁軛相比變大。相對於此，藉由如本實施形態般將作為鐵粉心之定子芯11之磁軛21斷裂分割而獲得複數個磁軛片21a，而於將該等磁軛片21a彼此組合時不易於斷裂面21b彼此之間形成空間。即，於相鄰之磁軛片21a，藉由使斷裂面21b彼此接觸，而磁軛片21a之斷裂面21b之凹凸與相鄰之磁軛片21a之斷裂面21b之凹凸接觸。藉此，即便為將磁軛21分割之構成，亦可抑制磁軛21之磁阻增大。再者，斷裂面21b彼此之接觸不僅包含形成於一斷裂面21b之凹凸相對於另一斷裂面21b之凹凸而使凹凸全部接觸之情形，亦包含凹凸之一部分接觸之情形。而且，如上所述，定子芯11係包含含有磁性材料之粒子之粉粒體之鐵粉心。因此，於將磁軛21斷裂分割時，即便於該磁軛21之一部分缺損之情形時，缺損片亦會沿著粒子與粒子之交界破裂。由此，可使缺損片之凹凸嚙合於磁軛片21a之缺損位置之凹凸，並且可使用接著劑等容易地將缺損片固定於磁軛片21a。因此，可容易地修復磁軛片21a。於定子芯為一體之情形時，相鄰之齒部之齒部前端部彼此之間隔較窄。因此，於相對於齒部捲繞定子線圈之情形時，於齒部前端部彼此之間幾乎無用以配置進行捲繞之裝置之噴嘴等之空間。由此，於定子芯為一體之情形時，能夠相對於齒部捲繞之定子線圈之匝數有限制。相對於此，本實施形態之定子芯11以磁軛片21a分別包含齒部22之方式被斷裂分割。藉此，能夠使用繞組裝置相對於各齒部22捲繞定子線圈12。因此，能夠相對於齒部22容易地捲繞定子線圈12，並且可增加能夠相對於齒部22捲繞之定子線圈12之匝數。＜實施形態之作用效果＞於本實施形態中，馬達1具備定子2。定子2具有：定子芯11，其包含沿軸線方向延伸之圓筒狀之磁軛21、及自該磁軛21之內周面朝向該磁軛21之徑向內側延伸之複數個齒部22；及定子線圈12，其捲繞於齒部22。定子芯11係使用包含磁性材料之粒子之粉粒體之鐵粉心，且具備藉由將磁軛21於圓周方向分割為複數個而形成之具有斷裂面21b之複數個磁軛片21a。複數個磁軛片21a分別包含齒部22。於本實施形態中，如上所述，定子芯11之磁軛21以各磁軛片21a包含齒部22之方式於圓周方向斷裂分割為複數個。藉此，能夠針對每一磁軛片21a而相對於齒部22捲繞定子線圈12。由此，與定子芯11為一體之構成相比，能夠增加捲繞於齒部22之定子線圈12之匝數。藉此，可提高馬達1之輸出扭矩。又，於本實施形態中，定子芯11係使用包含磁性材料之粒子之粉粒體之鐵粉心。由於定子芯11之磁軛21於圓周方向斷裂分割為複數個，故而於斷裂面21b形成凹凸。藉此，於如本實施形態之構成般藉由將磁軛片21a之斷裂面21b彼此組合而構成定子芯11之情形時，相鄰之磁軛片21a之於斷裂面21b之接觸點之個數，與藉由將複數個零件之平面彼此組合而構成定子芯之情形相比較多。由此，藉由本實施形態之構成，可抑制磁軛21之磁阻之增大。因此，藉由本實施形態之構成可謀求兼顧增加定子線圈12之匝數與抑制定子芯11之磁阻之增大。於本實施形態中，自上述軸線方向觀察磁軛21，斷裂面21b於相對於當電流流過定子線圈12時於磁軛21產生之磁通之方向而正交之方向延伸。於將磁軛21斷裂分割為複數個磁軛片21a之情形時，微細之缺損片可能自斷裂面21b脫落。由於缺損片脫落之部分於將磁軛片21a於斷裂面21b彼此組合時產生間隙，故而於該部分磁阻變大。相對於此，藉由形成如上述之構成之斷裂面21b，與自定子2之軸線方向觀察斷裂面於相對於在磁軛產生之磁通之方向而傾斜交叉之方向延伸之情形相比，斷裂面21b之面積較小。藉此，與斷裂面於相對於磁通之方向而傾斜交叉之方向延伸之情形相比，微細之缺損片自斷裂面21b脫落之可能性變低。由此，藉由本實施形態之構成，可降低於斷裂面21b與斷裂面21b之間形成間隙之可能性。因此，可更確實地抑制磁軛21之磁阻之增大。又，於斷裂面於相對於在磁軛產生之磁通之方向而傾斜交叉之方向延伸之情形時，於磁軛片之斷裂部分，磁軛片之徑向之壁厚於磁軛之圓周方向不同。此種磁軛片之壁厚之差影響該磁軛片之強度。相對於此，藉由如本實施形態之構成般，將斷裂面21b形成為於相對於在磁軛21產生之磁通之方向正交之方向延伸，可使磁軛片21a之圓周方向上之上述壁厚均等。由此，可抑制磁軛片21a之強度降低。於本實施形態中，齒部22具有：齒部本體部22a，其捲繞定子線圈12；及齒部前端部22b，其位於較該齒部本體部22a更靠齒部22之前端側。關於齒部本體部22a，於定子2之軸線方向上，齒部本體部22a之端部位於較磁軛21之端部更靠定子芯11之內側。於定子2之軸線方向上，齒部22之齒部本體部22a之端部位於較磁軛21之端部更靠定子芯11之內側。因此，於將定子線圈12捲繞於齒部本體部22a之情形時，可將定子線圈12相對於齒部22緊密地捲繞。因此，可不使馬達1大型化而增加定子線圈12之匝數。於本實施形態中，齒部22具有：齒部本體部22a，其供定子線圈12捲繞；及齒部前端部22b，其位於較齒部本體部22a更靠齒部22之前端側。齒部本體部22a於與磁軛21之徑向正交之剖面，於至少一部分具有齒部本體部22a之外側呈凸狀之R部22c。藉由於齒部22之齒部本體部22a設置R部22c，而於在該齒部本體部22a捲繞有定子線圈12之情形時，可防止該定子線圈12因齒部本體部22a而受損傷。更佳為於與磁軛2之徑向正交之剖面觀察齒部本體部22a，R部22c係設置於齒部本體部22a之所有角部分。藉此，於在齒部本體部22a捲繞有定子線圈12之情形時，可更確實地防止該定子線圈12因齒部本體部22a而受損傷。 (其他實施形態) 以上，對本發明之實施形態進行了說明，但上述實施形態僅為用以實施本發明之例示。由此，本發明並不限定於上述實施形態，能夠於不脫離其主旨之範圍內適當地對上述實施形態進行變形而實施。於上述實施形態中，定子芯11之磁軛21於圓周方向斷裂分割為複數個。然而，亦可將定子芯11於定子2之軸線方向分割為複數個。例如，如圖5所示，亦可將馬達100之定子芯101於定子之軸線方向分割為兩個。具體而言，定子芯101具有於上述軸線方向上呈同心狀積層之2個圓環狀零件102、103(筒部)。該等圓環狀零件102、103例如包含將定子芯101之磁軛111及齒部112分別於上述軸線方向分割為2個而成之部分。即，藉由將2個圓環狀零件102、103於上述軸線方向積層而構成定子芯101。再者，雖未特別圖示，但於2個圓環狀零件102、103之間配置有包含樹脂材料之絕緣構件。將該等圓環狀零件102、103分別如上述實施形態般於圓周方向斷裂分割為複數個磁軛片102a、103a。於此情形時亦與上述實施形態同樣地，以包含構成齒部112之部分之方式將圓環狀零件102、103分別斷裂分割。藉由如上述般利用於定子之軸線方向呈同心狀積層之複數個圓環狀零件102、103構成磁軛111，而與一體地構成之磁軛中之上述軸線方向之長度相比，於圓環狀零件102、103構成磁軛111之部分之上述軸線方向之長度較短。由此，可將圓環狀零件102、103於圓周方向容易地斷裂分割。而且，於上述構成中，磁軛111由在上述軸線方向上積層之複數個圓環狀零件102、103構成。由此，於上述軸線方向上，於2個圓環狀零件102、103之各者產生渦電流。因此，上述構成與定子芯於上述軸線方向上一體之構成相比，可減少定子芯101之於上述軸線方向產生之渦電流。藉此，可抑制定子芯101之溫度上升。因此，可提高馬達100之輸出扭矩。再者，於上述構成中，定子芯101係藉由將2個圓環狀零件102、103於上述軸線方向積層而構成。然而，定子芯亦可藉由將3個以上之圓環狀零件於上述軸線方向積層而構成。於上述實施形態中，以自上述軸線方向觀察磁軛21，於相對於當對定子線圈12通電而產生磁場之情形時於磁軛21產生之磁通之方向正交之方向延伸之方式，於磁軛片21a形成有斷裂面21b。然而，亦能以於相對於磁通之方向而傾斜交叉之方向延伸之方式於磁軛片形成有斷裂面21b。於上述實施形態中，馬達1係於圓筒狀之定子2之內側以旋轉中心與該定子2之軸線P一致之方式配置有圓筒狀之轉子3的內轉子型之馬達。然而，馬達1亦可為於圓筒狀或圓柱狀之定子之外側以旋轉中心與該定子之軸線一致之方式配置有圓筒狀之轉子的外轉子型之馬達。再者，於為外轉子型之馬達之情形時，定子芯之齒部自圓筒狀或圓柱狀之磁軛之外周面朝向該磁軛之徑向外側延伸。於上述實施形態中，馬達1為於轉子芯31之外周面上配置有場磁鐵32之SPM(Surface Permanent Magnet，表面式永磁體)之內轉子型之馬達。然而，馬達1可為於轉子芯內配置有場磁鐵之IPM(Interior Permanent Magnet，內置式永磁)之馬達，亦可為外轉子型之馬達。又，場磁鐵32及齒部22之個數亦可與本實施形態之構成不同。於上述實施形態中，磁軛片21a具有藉由將磁軛21分割而獲得之分割部21c、及齒部22。即，磁軛21以各磁軛片21a分別包含一個齒部22之方式被斷裂分割。然而，若各齒部22包含於不同之磁軛片21a，則可將磁軛21於圓周方向任意分割。例如，亦可將磁軛21之一部分分割為不包含齒部22之磁軛片21a。即，齒部22逐一設置於複數個磁軛片21a中之至少一部分磁軛片21a。具體而言，亦能以具有齒部22之磁軛片21a與不具有齒部22之磁軛片21a交替之方式將磁軛21斷裂分割。又，亦能以複數個不具有齒部22之磁軛片21a位於具有齒部22之磁軛片21a與具有齒部22之另一磁軛片21a之間之方式將磁軛21斷裂分割。又，如上述之圖5所示，於將定子芯101於定子之軸線方向分割為複數個之構成中，亦可將圓環狀零件102、103之至少一者以包含不具有齒部112之磁軛片之方式斷裂分割。於此情形時，亦能以一個以上不具有齒部112之磁軛片位於包含齒部112之至少一部分之磁軛片與包含齒部112之至少一部分之磁軛片之間的方式將圓環狀零件102、103斷裂分割。再者，於上述實施形態中，斷裂面21b意指於作為鐵粉心之定子芯11之磁軛21，於粒子失去凝聚力而被破壞時於各磁軛片21a形成之面。即，斷裂面21為於將磁軛21斷裂分割後磁軛片21a於磁軛21之圓周方向具有之面。斷裂面21b為於構成磁軛21之複數個磁軛片21a中之相鄰之磁軛片21a中具有與對向的斷裂面21b之凹凸接觸之凹凸之面。再者，所謂凹凸之接觸不僅包含形成於面之凹凸整體接觸之情形，亦包含凹凸之一部分接觸之情形。Hereinafter, each embodiment will be described with reference to the drawings. Furthermore, the dimensions of the constituent members in the drawings do not faithfully indicate the dimensions of the actual constituent members and the dimensional ratios of the constituent members. <Overall Configuration of Motor> FIG. 1 is a perspective view showing an overall configuration of a motor 1 (rotary motor) according to an embodiment of the present invention. The motor 1 includes a cylindrical stator 2 and a cylindrical rotor 3 disposed inside the stator 2 so that the center of rotation coincides with the axis P of the stator 2. That is, the motor 1 is formed in a cylindrical shape as a whole. The motor 1 is used, for example, for a motor for assisting pedaling of an electric bicycle or the like. Further, in Fig. 1, a symbol P denotes an axis extending in the direction of the cylinder axis of the stator 2. The stator 2 includes a stator core 11 formed in a cylindrical shape and a stator coil 12 wound around the stator core 11 . The stator core 11 is an iron powder core containing powder particles of a magnetic material. That is, the stator core 11 is integrally molded by fixing the powder and granules at a specific pressure using a molding die. FIG. 2 shows a specific configuration of the stator core 11. 2 is a front view of the stator core 11 as seen from the axial direction of the stator 2. As shown in FIG. 2, the stator core 11 is provided with a yoke 21 and a plurality of tooth portions 22. In the present embodiment, the stator core 11 has twelve tooth portions 22. The yoke 21 is formed in a cylindrical shape. Each of the tooth portions 22 extends from the inner circumferential surface of the yoke 21 toward the inner side of the yoke 21. The plurality of tooth portions 22 are formed on the inner circumferential surface of the yoke 21 so as to be arranged at equal intervals in the circumferential direction as viewed in the axial direction of the stator 2. As shown in FIGS. 1 and 2, the cylindrical yoke 21 of the stator core 11 is divided into a plurality of pieces in the circumferential direction. That is, the stator core 11 has a plurality of yoke pieces 21a formed by fracture division. The stator core 11 is divided and broken so that each of the yoke pieces 21a includes one tooth portion 22, respectively. Therefore, the stator core 11 is broken and divided into the same number of yoke pieces 21a as the tooth portions 22. In the case of the present embodiment, the stator core 11 is divided into twelve in the circumferential direction so that each of the yoke pieces 21a includes the tooth portion 22. Details of the fracture division of the stator core 11 will be described below. The tooth portion 22 is formed in a substantially T shape as viewed in the axial direction of the stator 2. That is, the tooth portion 22 has a tooth portion main portion 22a that extends from the inner circumferential surface of the yoke 21 toward the inner side of the yoke 21, and a tooth front end portion 22b that is located further than the tooth portion body portion 22a. The front end side of the portion 22. The tooth portion 22 is opposed to the rotor 3. The tooth tip end portion 22b is closer to the rotor 3 than the tooth portion body portion 22a. The tooth main body portion 22a is formed in a quadrangular prism shape extending from the inner circumferential surface of the yoke 21 toward the inner side of the yoke 21. In the tooth main body portion 22a, an R portion 22c is formed at a corner portion of a side surface extending in the extending direction of the tooth portion 22. The R portion 22c may be formed at all corner portions of the side surface of the tooth portion 22, or may be formed at a portion of the corner portion. That is, as shown in FIG. 3, the tooth main portion 22a has a R portion 22c that is convex toward the outer side of the tooth main portion 22a at least in a portion perpendicular to the extending direction of the tooth portion 22. Further, the extending direction of the tooth portion 22 is the same as the radial direction of the stator core 11 (the yoke 21). As shown in FIG. 1, the stator coil 12 is wound around the tooth main body portion 22a. By providing the R portion 22c on the side surface of the tooth main portion 22a as described above, it is possible to prevent the stator coil 12 wound around the tooth main portion 22a from being damaged. Furthermore, the R portion 22c may also be chamfered. As shown in FIG. 3, the tooth main portion 22a is formed such that the end portion of the tooth main portion 22a is located closer to the inner side of the motor 1 than the end portion of the yoke 21 in the axial direction of the stator 2. That is, the length of the tooth main portion 22a in the axial direction is shorter than the length of the yoke 21 in the axial direction. With this configuration, the stator coil 12 can be prevented from protruding toward the outer side of the stator 2 in the axial direction of the stator 2 in a state in which the stator coil 12 is wound around the tooth main portion 22a. As shown in FIG. 3, the dimension of the tooth tip end portion 22b in the width direction (the dimension in the circumferential direction when the stator 2 is viewed from the axial direction) and the dimension in the axial direction are larger than the width direction dimension of the tooth main portion 22a and the axial direction. The size. In other words, the tooth distal end portion 22b protrudes in the width direction and the axial direction with respect to the tooth main body portion 22a. With the configuration of the tooth tip end portion 22b, the stator coil 12 wound around the tooth portion main portion 22a can be prevented from falling off from the front end of the tooth portion 22. Therefore, the stator coil 12 can be wound more reliably with respect to the tooth body portion 22a. Further, by the configuration of the tooth tip end portion 22b as described above, when a magnetic field is generated by the stator coil 12 wound around the tooth main portion 22a, a large range can be formed around the tooth tip end portion 22b. Strong magnetic field. Though not specifically illustrated, the plurality of yoke pieces 21a obtained by the fracture division of the stator core 11 are held by a holding member or the like in a state in which the original stator cores 11 are combined. The holding member may be a member for holding a plurality of yoke pieces 21a, or may be constituted by a casing accommodating the motor 1. As shown in FIG. 1, the rotor 3 is formed in a cylindrical shape, and is disposed inside the stator 2 so that the center of rotation coincides with the axis P of the stator 2. Although not specifically illustrated, the rotor 3 is fixed to the rotating shaft so that the rotating shaft can pass therethrough so as to be rotatable integrally with the rotating shaft. The rotor 3 includes a rotor core 31 and a field magnet 32. The rotor core 31 is a cylindrical member including a magnetic material. A plurality of slits 31a for arranging the field magnets 32 are formed on the outer peripheral surface of the rotor core 31. Each of the slits 31a has a concave portion having a depth in which one of the field magnets 32 is partially exposed in a state where the field magnet 32 is disposed in the slit 31a. In the present embodiment, as shown in FIG. 1, a slit 31a is formed in the outer peripheral surface of the rotor core 31 at 14 locations. Further, each slit 31a is formed on the outer circumferential surface of the rotor core 31 from one end portion to the other end portion of the rotor core 31 in the axial direction of the rotor core 31. The field magnet 32 is a permanent magnet and is formed in a rectangular parallelepiped shape. The field magnet 32 is fixed to the slit 31a formed in the outer peripheral surface of the rotor core 31 in a state where one of the wall thickness directions is partially exposed. (Fracture Division of Stator Core) The fracture division of the yoke 21 of the stator core 11 will be described in detail with reference to Figs. 2 to 4 . 3 is a perspective view showing a schematic configuration of a yoke piece 21a obtained by breaking and dividing the yoke 21 of the stator core 11. FIG. 4 is a view schematically showing a direction of magnetic flux generated in the yoke 21 when the stator coil 12 is energized to generate a magnetic field. The yoke 21 of the stator core 11 is divided into a plurality of pieces in the circumferential direction. A plurality of yoke pieces 21a are formed by dividing the yoke 21 into a plurality of pieces in the circumferential direction in this manner. The yoke piece 21a has a divided portion 21c obtained by dividing the yoke 21, and a tooth portion 22. The yoke 21 is divided and divided so that each of the yoke pieces 21a includes one tooth portion 22, respectively. By dividing the stator core 11 in this manner, when the stator coil 12 is wound with respect to the tooth portion 22, it is not affected by the adjacent tooth portion 22. Thereby, the stator coil 12 can be easily wound around the tooth portion 22 of the yoke piece 21a, and the number of turns of the stator coil 12 wound around the tooth portion 22 can be increased. The divided portion 21c of the yoke piece 21a is obtained by dividing the cylindrical yoke 21 in the circumferential direction. Therefore, the divided portion 21c is formed in an arc shape as viewed in the axial direction of the stator 2. The divided portion 21c has a fracture surface 21b at both ends in the circumferential direction as viewed in the axial direction. That is, the yoke piece 21a has a fracture surface 21b in the circumferential direction of the yoke 21. The fracture surface 21b is formed by breaking and dividing the yoke 21 so that the yoke 21 extends in the radial direction of the yoke 21 as viewed from the axial direction. By energizing the stator coil 12 wound around the tooth portion 22, a magnetic flux is formed in the yoke 21 from the tooth portion 22 in the circumferential direction of the yoke 21 (see Fig. 4). Thereby, as shown in FIG. 4, the yoke 21 is viewed from the axial direction, and the fracture surface 21b is in the direction of the magnetic flux generated in the yoke 21 with respect to the case where the magnetic field is generated when the stator coil 12 is energized (FIG. 4). The dotted arrows extend in the orthogonal direction. By forming the fracture surface 21b having the above configuration, as compared with the case where the yoke 21 is viewed from the axial direction and the fracture surface 21b extends in a direction obliquely intersecting with respect to the direction of the magnetic flux generated in the yoke 21, The area of the fracture surface 21b is small. Thereby, compared with the case where the fracture surface extends in a direction obliquely intersecting with respect to the direction of the magnetic flux, the possibility that the fine defect piece is peeled off from the fracture surface 21b becomes low. Thus, with the configuration of the present embodiment, it is possible to reduce the possibility of forming a gap between the fracture surface 21b and the fracture surface 21b due to the falling of the defect sheet. Therefore, the increase in the magnetic resistance of the yoke 21 can be more reliably suppressed. Further, in the case where the fracture surface extends in a direction obliquely intersecting with respect to the direction of the magnetic flux generated in the yoke, the radial wall of the yoke piece is thicker than the circumferential direction of the yoke at the broken portion of the yoke piece. different. On the other hand, by forming the fracture surface 21b so as to extend in a direction orthogonal to the direction of the magnetic flux generated in the yoke 21, the yoke piece 21a can be formed on the circumference as in the configuration of the present embodiment. The above wall thickness of the direction is equal. Thereby, the strength reduction of the yoke piece 21a can be suppressed. In the present embodiment, the yoke 21 is viewed from the axial direction, and the fracture surface 21b extends in a direction orthogonal to the direction of the magnetic flux, and is not limited to the case where the fracture surface 21b intersects at right angles with respect to the direction of the magnetic flux. Also included in the case where a specific angular range including a right angle (for example, ranging from 80 degrees to 100 degrees) intersects. As described above, since the stator core 11 includes the iron powder core containing the particles of the magnetic material, when the stator core 11 is broken and divided, the stator core 11 is broken along the boundary between the particles and the particles. Thereby, the fracture surface 21b of the yoke piece 21a has a large number of irregularities. Therefore, when the yoke 21 is broken and divided to form the yoke piece 21a, the fracture surface 21b of the yoke piece 21a is combined with each other so as to restore the original shape of the yoke 21, the fracture surface 21b can be formed. The bumps mesh with each other. Thereby, it is not easy to form a space between the fracture faces 21b of the yoke piece 21a. Here, the fracture division means that the yoke 21 is brittlely broken by applying a force to the yoke 21. In other words, the fracture division means that the yoke 21 which is the stator core 11 of the iron powder core is brittlely broken in such a manner as to break along the boundary between the particles constituting the iron powder core and the particles. Therefore, a plurality of irregularities are formed in the fracture surface 21b formed when the yoke 21 is broken and divided. Thereby, the fracture surface 21b has a pear-like surface. In addition, the fracture surface 21b means a surface formed when the yoke 21 of the stator core 11 of the iron powder core is broken when the particles lose cohesion. In the case where the yoke sheets are formed by machining or the like as in the prior art, since the yoke pieces are in planar contact with each other, a gap is easily generated in the contact portion. Therefore, the magnetic resistance of the yoke in the case where the yoke is divided becomes larger than that of the integrated yoke. On the other hand, the yoke 21 as the stator core 11 of the iron powder core is fractured and divided to obtain a plurality of yoke pieces 21a, and the yoke pieces 21a are not easily broken when they are combined with each other. The faces 21b form a space between each other. In other words, the adjacent yoke pieces 21a are brought into contact with each other, whereby the unevenness of the fracture surface 21b of the yoke piece 21a is in contact with the unevenness of the fracture surface 21b of the adjacent yoke piece 21a. Thereby, even if the yoke 21 is divided, the magnetic resistance of the yoke 21 can be suppressed from increasing. Further, the contact between the fracture faces 21b includes not only the unevenness of the irregularities formed on one fracture surface 21b but also the irregularities of the other fracture surface 21b, and also the contact of one of the irregularities. Further, as described above, the stator core 11 is an iron powder core containing powder or granules of particles of a magnetic material. Therefore, when the yoke 21 is broken and divided, even if one of the yokes 21 is partially broken, the defective sheet is broken along the boundary between the particles and the particles. Thereby, the unevenness of the defect piece can be engaged with the unevenness of the defect position of the yoke piece 21a, and the defect piece can be easily fixed to the yoke piece 21a by using an adhesive or the like. Therefore, the yoke piece 21a can be easily repaired. In the case where the stator core is integrated, the front end portions of the tooth portions of the adjacent tooth portions are narrowed from each other. Therefore, in the case where the stator coil is wound with respect to the tooth portion, there is almost no space between the tip end portions of the tooth portions for arranging the nozzle or the like of the device to be wound. Therefore, when the stator core is integrated, the number of turns of the stator coil that can be wound with respect to the tooth portion is limited. On the other hand, the stator core 11 of the present embodiment is divided and divided so that the yoke pieces 21a each include the tooth portion 22. Thereby, the stator coil 12 can be wound with respect to each tooth part 22 using a winding device. Therefore, the stator coil 12 can be easily wound with respect to the tooth portion 22, and the number of turns of the stator coil 12 that can be wound with respect to the tooth portion 22 can be increased. <Operation and Effect of the Embodiment> In the present embodiment, the motor 1 includes the stator 2. The stator 2 includes a stator core 11 including a cylindrical yoke 21 extending in the axial direction, and a plurality of teeth 22 extending from the inner circumferential surface of the yoke 21 toward the radially inner side of the yoke 21; And the stator coil 12 is wound around the tooth portion 22. The stator core 11 is an iron core having a powder or granule containing particles of a magnetic material, and includes a plurality of yoke pieces 21a having a fracture surface 21b formed by dividing the yoke 21 into a plurality of circumferential directions. The plurality of yoke pieces 21a each include a tooth portion 22. In the present embodiment, as described above, the yoke 21 of the stator core 11 is divided into a plurality of yokes in the circumferential direction so that the yoke pieces 21a include the tooth portions 22. Thereby, the stator coil 12 can be wound with respect to the tooth portion 22 for each yoke piece 21a. Thereby, the number of turns of the stator coil 12 wound around the tooth portion 22 can be increased as compared with the configuration in which the stator core 11 is integrated. Thereby, the output torque of the motor 1 can be increased. Further, in the present embodiment, the stator core 11 is an iron powder core containing powder or granules of particles of a magnetic material. Since the yoke 21 of the stator core 11 is divided into a plurality of pieces in the circumferential direction, irregularities are formed on the fracture surface 21b. Therefore, in the case where the stator core 11 is formed by combining the fracture faces 21b of the yoke pieces 21a with each other as in the configuration of the present embodiment, the contact points of the adjacent yoke pieces 21a to the fracture faces 21b are The number is much larger than the case where the stator core is combined by combining the planes of a plurality of parts. Thus, with the configuration of the present embodiment, the increase in the magnetic resistance of the yoke 21 can be suppressed. Therefore, according to the configuration of the present embodiment, it is possible to increase the number of turns of the stator coil 12 and suppress the increase in the magnetic resistance of the stator core 11. In the present embodiment, the yoke 21 is viewed from the axial direction, and the fracture surface 21b extends in a direction orthogonal to the direction of the magnetic flux generated by the yoke 21 when a current flows through the stator coil 12. When the yoke 21 is broken and divided into a plurality of yoke pieces 21a, the fine defect piece may fall off from the fracture surface 21b. Since the portion where the defective piece is detached generates a gap when the yoke piece 21a is combined with each other on the fracture surface 21b, the magnetic resistance becomes large in this portion. On the other hand, by forming the fracture surface 21b having the above configuration, compared with the case where the fracture surface is observed in the direction from the axial direction of the stator 2 and extends obliquely with respect to the direction of the magnetic flux generated in the yoke, The area of the fracture surface 21b is small. Thereby, the possibility that the fine defect piece falls off from the fracture surface 21b becomes lower than the case where the fracture surface extends in a direction obliquely intersecting with respect to the direction of the magnetic flux. Therefore, according to the configuration of the present embodiment, it is possible to reduce the possibility of forming a gap between the fracture surface 21b and the fracture surface 21b. Therefore, the increase in the magnetic resistance of the yoke 21 can be more reliably suppressed. Further, in the case where the fracture surface extends in a direction obliquely intersecting with respect to the direction of the magnetic flux generated in the yoke, the radial wall of the yoke piece is thicker than the circumferential direction of the yoke at the broken portion of the yoke piece. different. The difference in wall thickness of such a yoke sheet affects the strength of the yoke sheet. On the other hand, as in the configuration of the present embodiment, the fracture surface 21b is formed to extend in a direction orthogonal to the direction of the magnetic flux generated in the yoke 21, so that the yoke piece 21a can be circumferentially oriented. The above wall thicknesses are equal. Thereby, the strength reduction of the yoke piece 21a can be suppressed. In the present embodiment, the tooth portion 22 has a tooth portion main portion 22a that winds the stator coil 12, and a tooth portion distal end portion 22b that is located closer to the front end side of the tooth portion 22 than the tooth portion main portion 22a. In the tooth main body portion 22a, the end portion of the tooth main portion 22a is located closer to the inner side of the stator core 11 than the end portion of the yoke 21 in the axial direction of the stator 2. In the axial direction of the stator 2, the end portion of the tooth main portion 22a of the tooth portion 22 is located closer to the inner side of the stator core 11 than the end portion of the yoke 21. Therefore, when the stator coil 12 is wound around the tooth main body portion 22a, the stator coil 12 can be tightly wound with respect to the tooth portion 22. Therefore, the number of turns of the stator coil 12 can be increased without increasing the size of the motor 1. In the present embodiment, the tooth portion 22 has a tooth portion main portion 22a for winding the stator coil 12, and a tooth portion distal end portion 22b which is located closer to the front end side of the tooth portion 22 than the tooth portion main portion 22a. The tooth main body portion 22a has a R portion 22c having a convex shape on the outer side of the tooth main body portion 22a in a cross section perpendicular to the radial direction of the yoke 21. When the R portion 22c is provided in the tooth main portion 22a of the tooth portion 22, when the stator coil 12 is wound around the tooth main portion 22a, the stator coil 12 can be prevented from being damaged by the tooth main portion 22a. . More preferably, the tooth main portion 22a is viewed in a cross section orthogonal to the radial direction of the yoke 2, and the R portion 22c is provided at all corner portions of the tooth main portion 22a. Thereby, when the stator coil 12 is wound around the tooth main portion 22a, the stator coil 12 can be more reliably prevented from being damaged by the tooth main portion 22a. (Other Embodiments) Although the embodiments of the present invention have been described above, the above embodiments are merely examples for carrying out the invention. Therefore, the present invention is not limited to the above-described embodiments, and the above-described embodiments can be appropriately modified without departing from the spirit and scope of the invention. In the above embodiment, the yoke 21 of the stator core 11 is divided into a plurality of pieces in the circumferential direction. However, the stator core 11 may be divided into a plurality of pieces in the axial direction of the stator 2. For example, as shown in FIG. 5, the stator core 101 of the motor 100 may be divided into two in the axial direction of the stator. Specifically, the stator core 101 has two annular members 102 and 103 (tube portions) which are concentrically stacked in the axial direction. The annular members 102 and 103 include, for example, a portion in which the yoke 111 and the tooth portion 112 of the stator core 101 are divided into two in the axial direction. In other words, the stator core 101 is configured by laminating the two annular members 102 and 103 in the axial direction. Further, although not shown in the drawings, an insulating member including a resin material is disposed between the two annular members 102 and 103. Each of the annular members 102 and 103 is divided into a plurality of yoke sheets 102a and 103a in the circumferential direction as in the above embodiment. Also in this case, as in the above-described embodiment, the annular members 102 and 103 are respectively divided and divided so as to include the portions constituting the tooth portions 112. The yoke 111 is formed by a plurality of annular members 102 and 103 which are concentrically stacked in the axial direction of the stator as described above, and is smaller than the length of the axial direction of the integrally formed yoke. The length of the axial direction of the portion of the annular yokes 102 and 103 constituting the yoke 111 is short. Thereby, the annular members 102 and 103 can be easily broken and divided in the circumferential direction. Further, in the above configuration, the yoke 111 is composed of a plurality of annular members 102 and 103 which are laminated in the axial direction. Thereby, an eddy current is generated in each of the two annular members 102 and 103 in the axial direction. Therefore, the above configuration can reduce the eddy current generated in the axial direction of the stator core 101 as compared with the configuration in which the stator core is integrated in the axial direction. Thereby, the temperature rise of the stator core 101 can be suppressed. Therefore, the output torque of the motor 100 can be increased. Further, in the above configuration, the stator core 101 is configured by laminating the two annular members 102 and 103 in the axial direction. However, the stator core may be formed by laminating three or more annular members in the axial direction. In the above-described embodiment, the yoke 21 is viewed from the axial direction, and is extended in a direction orthogonal to the direction in which the magnetic flux generated by the yoke 21 is orthogonal to the case where a magnetic field is generated when the stator coil 12 is energized. The yoke piece 21a is formed with a fracture surface 21b. However, it is also possible to form the fracture surface 21b on the yoke piece so as to extend in a direction obliquely intersecting with respect to the direction of the magnetic flux. In the above-described embodiment, the motor 1 is an inner rotor type motor in which the cylindrical rotor 3 is disposed inside the cylindrical stator 2 so that the center of rotation coincides with the axis P of the stator 2. However, the motor 1 may be an outer rotor type motor in which a cylindrical rotor is disposed on the outer side of the cylindrical or cylindrical stator so that the center of rotation coincides with the axis of the stator. Further, in the case of the outer rotor type motor, the tooth portion of the stator core extends from the outer peripheral surface of the cylindrical or cylindrical yoke toward the radially outer side of the yoke. In the above-described embodiment, the motor 1 is an inner rotor type motor in which SPM (Surface Permanent Magnet) of the field magnet 32 is disposed on the outer circumferential surface of the rotor core 31. However, the motor 1 may be a motor in which an IPM (Interior Permanent Magnet) of a field magnet is disposed in a rotor core, or may be an outer rotor type motor. Further, the number of the field magnets 32 and the tooth portions 22 may be different from the configuration of the embodiment. In the above embodiment, the yoke piece 21a has the divided portion 21c obtained by dividing the yoke 21, and the tooth portion 22. That is, the yoke 21 is divided and divided so that each of the yoke pieces 21a includes one tooth portion 22, respectively. However, if each of the tooth portions 22 is included in a different yoke piece 21a, the yoke 21 can be arbitrarily divided in the circumferential direction. For example, one of the yokes 21 may be divided into a yoke piece 21a that does not include the tooth portion 22. That is, the tooth portions 22 are provided one by one on at least a part of the yoke pieces 21a of the plurality of yoke pieces 21a. Specifically, the yoke 21 can be split and divided such that the yoke piece 21a having the tooth portion 22 and the yoke piece 21a having no tooth portion 22 alternate. Further, the yoke 21 can be split and divided so that the plurality of yoke pieces 21a having no tooth portions 22 are located between the yoke piece 21a having the tooth portion 22 and the other yoke piece 21a having the tooth portion 22. Further, as shown in FIG. 5 described above, in the configuration in which the stator core 101 is divided into a plurality of axes in the axial direction of the stator, at least one of the annular members 102 and 103 may include the portion having no tooth portion 112. The yoke piece is broken and divided. In this case, the ring can also be formed in such a manner that more than one yoke piece having no tooth portion 112 is located between the yoke piece including at least a portion of the tooth portion 112 and the yoke piece including at least a portion of the tooth portion 112. The shaped parts 102, 103 are broken and divided. Further, in the above embodiment, the fracture surface 21b means the yoke 21 which is the stator core 11 of the iron powder core, which is formed on the surface of each yoke piece 21a when the particles are broken by the cohesive force. In other words, the fracture surface 21 is a surface having the yoke piece 21a in the circumferential direction of the yoke 21 after the yoke 21 is divided and divided. The fracture surface 21b is a surface having irregularities in contact with the unevenness of the opposing fracture surface 21b in the adjacent yoke pieces 21a of the plurality of yoke pieces 21a constituting the yoke 21. Further, the contact of the unevenness includes not only the case where the unevenness of the surface is integrally contacted, but also the case where one of the irregularities is in contact with each other.

1、100‧‧‧馬達(旋轉電機)
2‧‧‧定子
3‧‧‧轉子
11、101‧‧‧定子芯
12‧‧‧定子線圈
21‧‧‧磁軛
21a‧‧‧磁軛片
21b‧‧‧斷裂面
21c‧‧‧分割部
22‧‧‧齒部
22a‧‧‧齒部本體部
22b‧‧‧齒部前端部
22c‧‧‧R部
31‧‧‧轉子芯
31a‧‧‧狹縫
32‧‧‧場磁鐵
102、103‧‧‧圓環狀零件(筒部)
102a`磁軛片
103a‧‧‧磁軛片
111‧‧‧磁軛
112‧‧‧齒部
P‧‧‧軸線1, 100‧‧‧ motor (rotary motor)
2‧‧‧stator
3‧‧‧Rotor
11, 101‧‧‧ stator core
12‧‧‧statar coil
21‧‧‧ yoke
21a‧‧‧Magnetic yoke
21b‧‧‧ fracture surface
21c‧‧‧ Division
22‧‧‧ teeth
22a‧‧‧ tooth body
22b‧‧‧ front end of the tooth
22c‧‧‧R
31‧‧‧Rotor core
31a‧‧‧slit
32‧‧ ‧ field magnet
102, 103‧‧‧Ring parts (cylinder)
102a` yoke piece
103a‧‧ yoke piece
111‧‧‧Y yoke
112‧‧‧ teeth
P‧‧‧ axis

圖1係表示本發明之實施形態之馬達之整體構成之立體圖。圖2係表示定子芯之構成之前視圖。圖3係表示磁軛片之構成之立體圖。圖4係模式性地表示藉由定子線圈之通電而於定子芯之磁軛產生之磁通之方向之圖。圖5係表示另一實施形態之馬達之整體構成之相當於圖1之圖。Fig. 1 is a perspective view showing the overall configuration of a motor according to an embodiment of the present invention. Fig. 2 is a front view showing the constitution of the stator core. Fig. 3 is a perspective view showing the configuration of a yoke piece. Fig. 4 is a view schematically showing the direction of the magnetic flux generated in the yoke of the stator core by energization of the stator coil. Fig. 5 is a view corresponding to Fig. 1 showing the overall configuration of a motor according to another embodiment.

1‧‧‧馬達(旋轉電機) 1‧‧‧Motor (rotary motor)

2‧‧‧定子 2‧‧‧stator

3‧‧‧轉子 3‧‧‧Rotor

11‧‧‧定子芯 11‧‧‧Silker core

12‧‧‧定子線圈 12‧‧‧statar coil

21‧‧‧磁軛 21‧‧‧ yoke

21a‧‧‧磁軛片 21a‧‧‧Magnetic yoke

21b‧‧‧斷裂面 21b‧‧‧ fracture surface

21c‧‧‧分割部 21c‧‧‧ Division

22‧‧‧齒部 22‧‧‧ teeth

22b‧‧‧齒部前端部 22b‧‧‧ front end of the tooth

31‧‧‧轉子芯 31‧‧‧Rotor core

31a‧‧‧狹縫 31a‧‧‧slit

32‧‧‧場磁鐵 32‧‧ ‧ field magnet

P‧‧‧軸線 P‧‧‧ axis

Claims

A rotary electric machine including a stator, wherein the stator includes a stator core including a cylindrical yoke extending in the axial direction, and a diameter from an inner circumferential surface or an outer circumferential surface of the yoke toward the yoke a plurality of teeth extending; and a stator coil wound around the tooth portion; wherein the stator core is made of a powder core containing particles of a magnetic material, and is provided in a circumferential direction of the yoke a plurality of yoke pieces of the fracture surface, wherein the tooth portions are respectively provided in at least a part of the plurality of yoke sheets having the fracture surface, and the plurality of yoke sheets having the fracture surface are The adjacent yoke sheets are in contact with the fracture surface of the adjacent yoke sheets.

The rotary electric machine according to claim 1, wherein the yoke is viewed from the axial direction, and the fracture surface extends in a direction orthogonal to a magnetic flux direction generated by the yoke when a current flows through the stator coil.

The rotary electric machine according to claim 1 or 2, wherein the yoke has a plurality of cylindrical portions concentrically stacked in the axial direction, and the plurality of cylindrical portions are divided in the circumferential direction so as to constitute the plurality of yoke sheets For multiples.

The rotary electric machine according to claim 1 or 2, wherein the tooth portion has a tooth body portion for winding the stator coil, and a tooth front end portion located closer to the tooth portion than the tooth portion body portion And the end portion of the tooth portion main portion is located closer to the inner side of the stator core than the end portion of the yoke.

The rotary electric machine according to claim 1 or 2, wherein the tooth portion has a tooth body portion for winding the stator coil, and a tooth front end portion located closer to the tooth portion than the tooth portion body portion The side portion of the tooth portion has a R portion that is convex toward the outer side of the tooth portion body portion in at least a portion of the cross section orthogonal to the radial direction of the yoke.

A rotary electric machine according to claim 1 or 2, further comprising a rotor, wherein the tooth portion faces the rotor.

The rotary electric machine according to claim 6, wherein the tooth portion has a tooth body portion for winding the stator coil, and a tooth front end portion which is closer to the rotor than the tooth body portion; and the tooth body The end portion of the tooth main portion is located closer to the inner side of the stator core than the end portion of the yoke in the axial direction.

A rotary electric machine according to claim 1 or 2, wherein said fracture surface has irregularities.

The rotary electric machine according to claim 3, wherein the tooth portion has a tooth portion main portion for winding the stator coil, and a tooth front end portion located closer to a front end side of the tooth portion than the tooth portion main portion; Further, in the axial direction of the tooth main body portion, an end portion of the tooth main portion is located closer to an inner side of the stator core than an end portion of the yoke.

The rotary electric machine according to claim 3, wherein the tooth portion has a tooth portion main portion for winding the stator coil, and a tooth front end portion located closer to a front end side of the tooth portion than the tooth portion main portion; Further, the tooth main body portion has a R portion that is convex toward the outer side of the tooth main portion at least in a cross section perpendicular to the radial direction of the yoke.

A stator which is a stator of a rotating electrical machine and has a stator core including a cylindrical yoke extending in the axial direction, and a radial extension from the inner circumferential surface or the outer circumferential surface of the yoke toward the yoke a plurality of teeth; and a stator coil wound around the tooth portion; and the stator core is made of a powder core containing particles of a magnetic material, and has a fracture surface in a circumferential direction of the yoke a plurality of yoke pieces, wherein the tooth portions are respectively provided on at least a part of the plurality of yoke sheets having the fracture surface, and adjacent to the plurality of yoke sheets having the fracture surface The yoke sheet is in contact with the fracture surface of the adjacent yoke sheet.

The stator of claim 11, wherein the fracture surface has irregularities.