Electric rotating machine

According to an embodiment, an electric rotating machine includes a rotor element, an annular coil, a plurality of stator cores, and a plurality of wedge members. The rotor element is rotatable around a rotation axis. The coil is provided to be coaxial with the rotation axis. The plurality of stator cores are provided opposite to the rotor element and each includes a pair of magnetic pole parts opposing each other with the coil being interposed therebetween. Each of the plurality of wedge members is arranged between adjacent stator cores to apply preloads to the adjacent stator cores, the preloads containing components in a rotation direction of the rotor element and being opposite to each other.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2014-113031, filed May 30, 2014, the entire contents of which are incorporated herein by reference.

FIELD

Embodiments described herein relate generally to a transversal flux electric rotating machine that generates a magnetic path along the axis of rotation thereof, and an electrically driven vehicle, wind turbine generator, and elevator device using the electric rotating machine.

BACKGROUND

Demands have arisen for further improving the performance of electromagnetic motors for reasons such as energy saving and CO2reduction, and the performance represented by areas such as downsizing, weight reduction, high efficiency, high torque, and high output are rapidly improving daily. When classified in accordance with the direction of a magnetic flux, the electromagnetic motors can be classified into (1) a radial flux motor, (2) an axial flux motor, and (3) a transversal flux motor. Of these motors, the radial flux motor is particularly superior in cost performance, and has conventionally been used in a wide variety of products in the world of industry as a typical mechanical element of a general-purpose actuator. Also, the axial flux motor has the structural feature that can cope with a complicated magnetic path arrangement in three-dimensional directions, but makes the use of widely-used conventional laminated steel difficult. Axial flux motors such as this are particularly applied to the field of medium/large-sized, low-profile, large-diameter motors.

Furthermore, the transversal flux motor has the following feature; a basic unit is formed by a rotor including a permanent magnet, and an armature (which forms a split toroidal core) including an annular coil formed around the rotation axis of the rotor, and a plurality of approximately U-shaped stator cores (to be referred to as U-shaped stator cores hereinafter) are formed so as to cover the annular coil on the circumference around the rotation axis, and two or more basic units are arranged along the rotation axis with a predetermined relative phase angle around the rotation axis. This arrangement can achieve a high torque by multiple poles relatively easily, and can achieve high-efficiency magnetic field generation by the split toroidal core structure. That is, when compared to the radial flux motor and axial flux motor requiring a stator core including a plurality of slots on the circumference around the rotation axis, a coil wound around this slot part, and a dead space for coil assembling and insertion, etc., the transversal flux motor only requires the plurality of U-shaped stator cores to be formed on the circumference around the rotation axis. This generally makes it easy to increase the number of poles. Also, the armature including the toroidal coil and U-shaped stator cores has a structure from which a magnetic flux generated by the coil hardly leaks outside. Since this increases the field generation efficiency of the coil, the transversal flux motor can be expected to be downsized more than the radial flux motor and axial flux motor having the coil end.

When the rotor rotates in the transversal flux motor, a magnetic force which intermittently changes its direction acts on the U-shaped stator cores in the rotation direction. This magnetic force vibrates the U-shaped stator cores. This vibration not only decreases the motor's strength, but also generates noise. Furthermore, as the torque increases, a cogging torque which causes torque variations generally increases as well, and this presumably further increases the generation of vibrations. Therefore, demands have arisen for reducing the generation of vibrations in the transversal flux motor.

DETAILED DESCRIPTION

According to an embodiment, an electric rotating machine includes a rotor element, an annular coil, a plurality of stator cores, and a plurality of wedge members. The rotor element is rotatable around a rotation axis. The coil is provided to be coaxial with the rotation axis. The plurality of stator cores are provided opposite to the rotor element and each includes a pair of magnetic pole parts opposing each other with the coil being interposed therebetween. Each of the plurality of wedge members is arranged between adjacent stator cores to apply preloads to the adjacent stator cores, the preloads containing components in a rotation direction of the rotor element and being opposite to each other.

Hereinafter, various embodiments will be described with reference to the accompanying drawings. In the following embodiments, like reference numerals denote like elements, and a repetitive explanation will be omitted.

First Embodiment

FIG. 1schematically shows an electric rotating machine100according to the first embodiment. As shown inFIG. 1, the electric rotating machine100includes a rotor101supported by a bearing (not shown) so as to be rotatable around a rotation axis z, and a stator102which opposes the outer circumferential surface of the rotor101with a predetermined gap between them. The rotor101has an approximately cylindrical shape around the rotation axis z. The stator102has an approximately cylindrical shape coaxial with the rotation axis z, and is placed so as to cover the rotor101around the rotation axis z. The rotor101is positioned inside the stator102.

FIG. 2schematically shows the electric rotating machine100in a state in which it is disassembled into the rotor101and stator102and the stator102is partially cut away. As shown inFIG. 2, the electric rotating machine100is a three-stage (three-phase) electric rotating machine in which three basic units103are arranged in the rotation-axis direction (the direction of the rotation axis z). Each basic unit103includes one rotor element110, and one armature120opposing the rotor element110. Note that the number of basic units103is determined in accordance with the design conditions, and can be an arbitrary integer that is two or more. The output and torque of the electric rotating machine100can easily be adjusted by changing the number of basic units103.

The three rotor elements110are fixed to a shaft111extending along the rotation axis z. The shaft111is rotatably supported by the bearing (not shown). Accordingly, the rotor elements110can rotate around the rotation axis z. Each rotor element110includes a rotor core (not shown) and a permanent magnet (not shown). A plurality of magnetic poles are provided on the outer circumferential surface of the rotor element110so that N poles and S poles are alternately arranged.

The three armatures120are housed in an annular or cylindrical casing121, and connected to each other by the casing121. The material of the casing121can be any material which satisfies the mechanical strength required of the electric rotating machine100. In this embodiment, the casing121is common to the three armatures120. The casing121can be regarded as an element of each armature120. Note that a plurality of casings121may be provided for a plurality of armatures120. In this case, the plurality of casings121are fixed to each other by using combinations of bolts and nuts or an adhesive. Members133made of a nonmagnetic material may also be provided between the armatures120.

FIG. 3schematically shows the stator102in a state in which the casing121is partially cut away.FIG. 4is a perspective view schematically showing one of the armatures120shown inFIG. 2.FIG. 5is an exploded perspective view in which the armature120is disassembled in the rotation-axis direction. The three basic units103can have the same structure, so the two other armatures120can have the same structure as that of the armature120shown inFIGS. 4 and 5. As shown inFIG. 3, the armature120includes an armature coil122, a plurality of stator cores123, a plurality of core holders124, and a plurality of wedge members125.

The plurality of core holders124and the plurality of wedge members125are alternately arranged between the stator cores123, and thereby the plurality of stator cores123, the plurality of core holders124, and the plurality of wedge members125form an integrated annular body as a whole. Specifically, as shown inFIG. 4, the plurality of stator cores123, the plurality of core holders124, and the plurality of wedge members125are arranged in the order of a stator core123-1, core holder124-1, stator core123-2, wedge member125-1, stator core123-3, core holder124-2, stator core123-4, wedge member125-2, stator core123-5, and so on. The annular body is formed so as to cover the armature coil122around the rotation axis z.

In the example shown inFIG. 4, the number of stator cores123is 24, the number of core holders124is 12, and the number of wedge members125is 12. When the number of stator cores123is 24, the number of magnetic poles of the armature120is, for example, 48. In this example, the stator cores123are arranged at a circumferential pitch of 15 degrees, the core holders124are arranged at a circumferential pitch of 30 degrees, and the wedge members125are arranged at a circumferential pitch of 30 degrees.

As shown inFIG. 5, the armature coil122is formed into an annular shape around the rotation axis z. That is, the armature coil122is a toroidal coil coaxial with the rotation axis z. The armature coil122is supported by a support member (not shown), and fixed to the annular body. The armature coil122can be made of a conductive material such as copper, aluminum, or an alloy containing at least one of copper and aluminum.

The stator cores123are arranged so as to oppose the outer circumferential surface of the rotor element110with a predetermined gap between them. Each of the stator cores123is formed into an approximate U shape, and includes a pair of magnetic pole parts123A and123B opposing each other in the rotation-axis direction with the armature coil122being interposed between them, and an outer circumferential part123C positioned between the magnetic pole parts123A and123B. The magnetic pole part123A extends from one end of the outer circumferential part123C toward the rotor element110(i.e., in the radial direction pointing to the rotation axis z), and the magnetic pole part123B extends from the other end of the outer circumferential part123C toward the rotor element110. The magnetic pole parts123A and123B oppose the outer circumferential surface of the rotor element110with a predetermined gap between them. The stator core123is made of a ferromagnetic material.

The core holders124form first support members for fixing the stator cores123in a contact state. Each core holder124is formed into an approximate U shape. The core holder124includes first and second end parts124A and124B opposing each other with the armature coil122being interposed between them, and an outer circumferential part124C positioned between the first and second end parts124A and124B. The first end part124A extends from one end of the outer circumferential part124C toward the rotor element110, and the second end part124B extends from the other end of the outer circumferential part124C toward the rotor element110. The first and second end parts124A and124B oppose the rotor element110. The core holder124narrows toward the rotor element110. Specifically, the width of the core holder124in the rotation direction decreases toward the rotor element110. The sectional shape of the core holder124in a plane perpendicular to the rotation axis z is an approximate fan shape or trapezoidal shape. Screw holes128are formed in an outer circumferential surface124D of the core holder124. The core holder124is made of a nonmagnetic material. More preferably, the core holder124is made of an electrically insulating nonmagnetic material.

As shown inFIG. 3, the core holder124is fixed to the casing121in a contact state. The casing121forms a second support member for fixing the core holder124in a contact state. The core holder124is fixed to the casing121in a state in which the outer circumferential surface124D is in contact with an inner circumferential surface121A of the casing121. In this embodiment, the core holder124is fastened to the casing121by bolts130. A plurality of through holes126are formed in the casing121. The bolt130is inserted into the through hole126from outside the casing121, and is threadably engaged with the screw hole128of the core holder124. In addition, a plurality of screw holes127are formed in the casing121.

The core holder124is placed between two adjacent stator cores123, and fixes the stator cores123in a contact state. The stator cores123can be fixed to the core holder124by an optimum method selected in accordance with the acting torque or machine dimensions. As the fixing method, bolt fastening, adhesion, or the like is used. In a state in which the stator cores123are fixed to the core holder124, the first end part124A, second end part124B, and outer circumferential part124C of the core holder124are respectively in contact with the magnetic pole part123A, magnetic pole part123B, and outer circumferential part123C of the stator core123. The stator cores123are thus fixed to the casing121by the core holder124. Consequently, the vicinity of the outer circumferential part123C of the stator core123is supported and fixed with high rigidity.

Each wedge member125is formed into an approximate U shape. The wedge member125includes first and second end parts125A and125B opposing each other with the armature coil122being interposed between them, and an outer circumferential part125C positioned between the first and second end parts125A and125B. The first end part125A extends from one end of the outer circumferential part125C toward the rotor element110, and the second end part125B extends from the other end of the outer circumferential part125C toward the rotor element110. The first and second end parts125A and125B oppose the rotor element110. The wedge member125narrows toward the rotor element110. Specifically, the width of the wedge member125in the rotation direction decreases toward the rotor element110. The sectional shape of the wedge member125in the plane perpendicular to the rotation axis z is an approximate fan shape or trapezoidal shape. The wedge member125is made of a nonmagnetic material. More preferably, the wedge member125is made of an electrically insulating nonmagnetic material.

The wedge member125is placed between two adjacent stator cores123, and fixed to the stator cores123in a contact state. As the fixing method, bolt fastening, adhesion, or the like is used. The first end part125A, second end part125B, and outer circumferential part125C of the wedge member125are respectively in contact with the magnetic pole part123A, magnetic pole part123B, and outer circumferential part123C of the stator core123. A setscrew132is threadably engaged with the screw hole127of the casing121from outside the casing121. The distal end of the setscrew132comes in contact with the outer circumferential part125C of the wedge member125, and the wedge member125is pressed toward the rotor element110by the setscrew132. That is, a preload containing a radial-direction component pointing to the rotation axis z is applied to the wedge member125. Consequently, preloads containing rotation-direction components are applied to the two stator cores123in contact with the wedge member125. The stator cores123receive preloads in opposite directions. For example, the stator core123-2shown inFIG. 4is applied a preload from the wedge member125-1in a direction indicated by an arrow A, and pressed against the core holder124-1. The stator core123-3is applied a preload from the wedge member125-1in a direction indicated by an arrow B, and pressed against the core holder124-2. By thus forming the wedge member125between the stator cores123, the vicinities of the magnetic pole parts123A and123B of the stator cores123can be fixed with high rigidity.

In this embodiment, the stator cores123, core holders124, and wedge members125form an integrated annular body, and the wedge member125is placed between the stator cores123. Therefore, the vicinities of the magnetic pole parts123A and123B of the stator core123are supported and fixed with high rigidity. In addition, the stator core123is fixed to the casing121by using the core holder124. Accordingly, the position of the stator core123can be further stabilized in an assembling process, so the vicinity of the outer circumferential part123C of the stator core123is supported and fixed with high rigidity. This embodiment can thus improve the rigidity for supporting the stator core123.

When using the electric rotating machine100as a motor, a power supply (not shown) applies a three-phase alternating current to the electric rotating machine100. As a consequence, the rotor101rotates. As the rotor101rotates, a magnetic force which intermittently changes its direction acts on the magnetic pole parts123A and123B of the stator core123in the rotation direction. As described above, the stator core123is supported and fixed with high rigidity in this embodiment. Therefore, it is possible to prevent the stator core123from vibrating due to the magnetic force acting on the magnetic pole parts123A and123B when the electric rotating machine100is driven. When using an adhesive for fixing the wedge member125and stator core123, the adhesive gives a vibration damping effect, so the generation of vibrations can further be reduced. Since the generation of vibrations is reduced, the generation of noise caused by the vibrations can be reduced as well. This makes it possible to prevent a decrease in strength caused by the vibrations.

Furthermore, heat generated by a copper loss of the armature coil122caused when an electric current is supplied, generated by an iron loss of the stator core123caused by rotational driving, or generated by a magnetic flux generated from the armature coil122, is extracted (radiated) by the casing121by heat transfer from the core holder124. Therefore, heat removal can effectively be performed.

Note that the same effects as described above can be obtained even when using the electric rotating machine100as a generator.

In the electric rotating machine100according to this embodiment as described above, the plurality of stator cores123, the plurality of core holders124, and the plurality of wedge members125come in contact with each other and form an integrated annular body as a whole, and the plurality of core holders124are fixed to the casing121. This structure improves the rigidity for supporting the stator core123. As a result, it is possible to reduce vibrations generated when the electric rotating machine100is driven.

Note that this embodiment has been explained by taking, as an example, the case in which the number of stator cores123is 24 and the number of magnetic poles of the rotor element110is 48 in each of the basic units103. However, the number of stator cores123and the number of magnetic poles of the rotor element110are not limited to those of this example, and optimum numbers can be selected in accordance with the designed specifications of an application device. The numbers of core holders124and wedge members125change in accordance with the number of stator cores123.

Second Embodiment

In the second embodiment, an explanation of the same parts as in the first embodiment will be omitted as needed, and the explanations will focus on those parts different from the first embodiment.

FIG. 6schematically shows an electric rotating machine200according to the second embodiment. As shown inFIG. 6, the electric rotating machine200includes a rotor101supported by a bearing (not shown) so as to be rotatable around a rotation axis z, and a stator202which opposes the outer circumferential surface of the rotor101with a predetermined gap between them. The stator202has an approximately cylindrical shape coaxial with the rotation axis z. The rotor101is positioned inside the stator202.

FIG. 7schematically shows the electric rotating machine200in a state in which it is disassembled into the rotor101and stator202. As shown inFIG. 7, the electric rotating machine200is a three-stage (three-phase) electric rotating machine in which three basic units203are arranged in the rotation-axis direction. Each basic unit203includes one rotor element110, and one armature220opposing the rotor element110. Note that the number of basic units203is determined in accordance with the design conditions, and can be an arbitrary integer that is two or more.

The armatures220include core holder integrated casings228, and are connected to each other by the core holder integrated casings228. The core holder integrated casings228are fixed to each other by using a method such as bolt fastening, adhesion, or a combination thereof. The core holder integrated casing228is made of a nonmagnetic material. More preferably, the core holder integrated casing228is made of an electrically insulating nonmagnetic material.

FIG. 8schematically shows the stator202in a state in which the core holder integrated casing228is partially cut away.FIG. 9is a perspective view schematically showing one of the armatures220shown inFIG. 7.FIG. 10is an exploded perspective view in which the armature220is disassembled in the rotation-axis direction. The three basic units203can have the same structure, so the two other armatures220can have the same structure as that of the armature220shown inFIGS. 9 and 10. As shown inFIG. 9, the armature220further includes an armature coil122, a plurality of stator cores123, and a plurality of wedge members125. The armature coil122, the plurality of stator cores123, and the plurality of wedge members125are housed in the core holder integrated casing228.

As shown inFIG. 10, the core holder integrated casing228includes first and second parts228A and228B opposing each other in the rotation-axis direction. The first part228A includes a core holder part224A and outer circumferential part221A. The second part228B includes a core holder part2248and outer circumferential part221B. Projections234for positioning the stator cores123are formed on the core holder parts224A and224B. The projections234determine the positions of the stator cores123in the radial direction.

The first and second parts228A and228B are integrated by sandwiching the armature coil122, stator cores123, and wedge members125in the rotation-axis direction, and fixed by using a method such as bolt fastening, adhesion, or a combination thereof. As shown inFIG. 8, an approximately U-shaped core holder224is formed by combining the core holder parts224A and224B. The core holder224forms a first support member for fixing the stator core123in a contact state. Also, an approximately annular casing221is formed by combining the outer circumferential part221A and221B. The casing221forms a second support member for fixing the core holder224in a contact state. That is, the core holder integrated casing228is formed by integrating the core holders224and casing221. Each of the core holders224extends from the inner circumferential surface of the casing221toward the rotor element110. The core holder224can have the same shape as that of the core holder124according to the first embodiment, except for the projection234. Note that at least one of the core holders224may also be a member different from the core holder integrated casing221. This core holder224is fixed to the casing221in a contact state by using a method such as bolt fastening or adhesion.

The plurality of core holders224and the plurality of wedge members125are alternately arranged between the stator cores123, and the plurality of stator cores123, the plurality of core holders224, and the plurality of wedge members125form an integrated annular body as a whole. Specifically, as shown inFIG. 9, the plurality of stator cores123, the plurality of core holders224, and the plurality of wedge members125are arranged in the order of a stator core123-1, core holder224-1, stator core123-2, wedge member125-1, stator core123-3, core holder224-2, stator core123-4, wedge member125-2, stator core123-5, and so on.

As shown inFIG. 10, a plurality of screw holes127are formed in the core holder integrated casing228. As shown inFIG. 8, a setscrew132is threadably engaged with the screw hole127from outside the core holder integrated casing228. The distal end of the setscrew132comes in contact with an outer circumferential part125C of the wedge member125, and the wedge member125is pressed toward the rotor element110by the setscrew132. Consequently, preloads containing rotation-direction components are applied to two stator cores123in contact with the wedge member125. The stator cores123receive preloads in opposite directions. For example, the stator core123-2shown inFIG. 9receives a preload from the wedge member125-1toward the core holder224-1. The stator core123-3receives a preload from the wedge member125-1toward the core holder224-2. By thus forming the wedge member125between the stator cores123, the vicinities of the magnetic pole parts123A and123B of the stator cores123can be fixed with high rigidity.

In the electric rotating machine200according to this embodiment as described above, the plurality of stator cores123, the plurality of core holders224, and the plurality of wedge members125come in contact with each other and form an integrated annular body as a whole, and the plurality of core holders224are integrated with the casing221. This structure improves the rigidity for supporting the stator core123. As a result, it is possible to reduce vibrations generated when the electric rotating machine200is driven. Since the generation of vibrations is reduced, the generation of noise caused by vibrations can be reduced as well, so it is possible to prevent a decrease in strength caused by vibrations.

Furthermore, heat generated by a copper loss of the armature coil122caused when an electric current is supplied and generated by an iron loss of the stator core123caused by rotational driving or a magnetic flux generated from the armature coil122is extracted (radiated) by the casing221by heat conduction from the core holder224. Therefore, heat removal can effectively be performed. Consequently, this embodiment in which the core holder224is integrated with the casing221can achieve the rigidity for supporting the stator core123and the heat extraction performance higher than those of the first embodiment.

Third Embodiment

In the third embodiment, an explanation of the same parts as in the first embodiment will be omitted as needed, and the explanations will focus on those parts different from the first embodiment.

FIG. 11schematically shows an electric rotating machine300according to the third embodiment. As shown inFIG. 11, the electric rotating machine300includes a rotor101supported by a bearing (not shown) so as to be rotatable around a rotation axis z, and a stator302which opposes the outer circumferential surface of the rotor101with a predetermined gap between them. The stator302has an approximately cylindrical shape, and is arranged to be coaxial with the rotation axis z. The rotor101is positioned inside the stator302.

FIG. 12schematically shows the electric rotating machine300in a state in which it is disassembled into the rotor101and stator302. As shown inFIG. 12, the electric rotating machine300is a three-stage (three-phase) electric rotating machine in which three basic units303are arranged in the rotation-axis direction. Each basic unit303includes one rotor element110, and one armature320opposing the rotor element110. Note that the number of basic units303is determined in accordance with the design conditions, and can be an arbitrary integer that is two or more.

FIG. 13schematically shows the stator302in a state in which it is partially cut away.FIGS. 14A and 14Bare perspective views schematically showing one of the three armatures320shown inFIG. 12in different directions.FIG. 15is an exploded perspective view in which the armature320is disassembled in the rotation-axis direction. The three basic units303can have the same structure, so the two other armatures320can have the same structure as that of the armature320shown inFIGS. 14A, 14B, and 15.

As shown inFIG. 14A, the armature320includes an armature coil122, a plurality of stator cores123, a core holder integrated casing328, and a plurality of wedge members325. As shown inFIG. 15, the core holder integrated casing328is formed by integrating a casing321and a plurality of core holders324. The core holder324forms a first support member for fixing the stator core123in a contact state, and the casing321forms a second support member for fixing the core holder324in a contact state. The core holder integrated casing328is made of a nonmagnetic material. More preferably, the core holder integrated casing328is made of an electrically insulating nonmagnetic material. Note that at least one of the core holders324may also be a member different from the core holder integrated casing328. This core holder324is fixed to the casing321in a contact state by using a method such as bolt fastening or adhesion.

The casing321is an annular member. The core holders324are arranged so as to cover the casing321around the rotation axis z. The casing321is positioned between magnetic pole parts123A and123B of the stator core123. The core holder324is formed into an approximate L shape. The core holder324includes an outer circumferential part324C, and an end part324A extending from one end of the outer circumferential part324C toward the rotor element110. The end part324A opposes the rotor element110. The core holder324narrows toward the rotor element110. Specifically, the width of the core holder324in the rotation direction decreases toward the rotor element110. The sectional shape of the core holder324in a plane perpendicular to the rotation axis z is an approximate fan shape or trapezoidal shape. A through hole326is formed in the side surface of the core holder integrated casing328, and a screw hole127is formed in the outer circumferential surface of the core holder integrated casing328. The through holes326are used to connect and fix the three armatures320. As shown inFIG. 13, the armatures320are connected and fixed to each other by bolts330and nuts331. Each bolt330is inserted sideways into the through holes326of the three armatures320, and engaged with the nut331.

The wedge member325has an approximately square pillar shape which narrows toward the rotor element110. The width of the wedge member325in the rotation direction decreases toward the rotor element110. The sectional shape of the wedge member325in a plane perpendicular to the rotation axis z is an approximate fan shape or trapezoidal shape.

Both the core holder324and wedge member325are arranged between two adjacent stator cores123. The end part324A and outer circumferential part324C of the core holder324are respectively in contact with the magnetic pole part123A and an outer circumferential part123C of the stator core123, and the wedge member325is in contact with the magnetic pole part123B of the stator core123. As shown inFIG. 14B, a plurality of sets of the core holders324and wedge members325and the plurality of stator cores123are alternately arranged, and the plurality of stator cores123, the plurality of core holders324, and the plurality of wedge members325form an integrated annular body as a whole. Specifically, as shown inFIG. 14B, the plurality of stator cores123, the plurality of core holders324, and the plurality of wedge members325are arranged in the order of a stator core123-1, a set of a core holder324-1and wedge member325-1, a stator core123-2, a set of a core holder324-2and wedge member325-2, stator core123-3, and so on.

In the example shown inFIG. 14B, the number of stator cores123is 24, the number of core holders324is 24, and the number of wedge members325is 24. In this example, the stator cores123are arranged at a circumferential pitch of 15 degrees, the core holders324are arranged at a circumferential pitch of 15 degrees, and the wedge members325are arranged at a circumferential pitch of 15 degrees.

Note that the explanation has been made by taking the case in which the number of stator cores123included in each armature320is 24 as an example. However, the number of stator cores123is not limited to that of this example, and an optimum number can be selected in accordance with the designed specifications of an application device. The numbers of core holders324and wedge members325change in accordance with the number of stator cores123.

As shown inFIG. 13, a setscrew132is threadably engaged with the screw hole127of the core holder integrated casing328from outside the casing321. The distal end of the setscrew132comes in contact with the wedge member325, and the wedge member325is pressed toward the rotor element110by the setscrew132. Consequently, preloads containing rotation-direction components are applied to the two stator cores123(more specifically, the magnetic pole parts123B of the stator cores123) in contact with the wedge member325. The stator cores123receive preloads in opposite directions. For example, the stator core123-2shown inFIG. 14Breceives a preload from the wedge member325-2toward the wedge member325-1. The stator core123-3receives a preload from the wedge member325-2toward the wedge member325-3. By thus inserting the wedge member125between the stator cores123, the vicinities of the magnetic pole parts123B of the stator cores123can be fixed with high rigidity. In addition, the magnetic pole part123A of the stator core123is sandwiched between the core holders324, so the vicinity of the magnetic pole part123A is also fixed with high rigidity.

In the electric rotating machine300according to this embodiment as described above, the plurality of stator cores123, the plurality of core holders324, and the plurality of wedge members325come in contact with each other and form an integrated annular body as a whole, and the plurality of core holders324are integrated with the casing321. This structure improves the rigidity for supporting the stator core123. As a result, it is possible to reduce vibrations generated when the electric rotating machine300is driven. Since the generation of vibrations is reduced, the generation of noise caused by the vibrations can be reduced as well, so it is possible to prevent a decrease in strength caused by the vibrations.

Furthermore, heat generated by a copper loss of the armature coil122caused when an electric current is supplied, generated by an iron loss of the stator core123caused by rotational driving, or by a magnetic flux generated from the armature coil122, is extracted by the casing321by heat conduction from the core holder324, and is further extracted by the stator core123as well. Therefore, heat removal can effectively be performed.

Fourth Embodiment

The fourth embodiment is a modification of the first embodiment. The difference of the fourth embodiment from the first embodiment is a partial structure of an armature. In the fourth embodiment, an explanation of the same parts as in the first embodiment will be omitted as needed, and the explanations will focus on those parts different from the first embodiment.

FIG. 16schematically shows an armature420of an electric rotating machine according to the fourth embodiment. As shown inFIG. 16, the armature420includes an armature coil122(not shown inFIG. 16), a plurality of stator cores123, a core holder integrated casing428, and a plurality of wedge members125.

FIG. 17is a perspective view schematically showing the core holder integrated casing428.FIG. 18is an exploded perspective view in which the armature420is disassembled in the rotation-axis direction. As shown inFIG. 17, the core holder integrated casing428includes a coil holder429for supporting the armature coil122, and a plurality of core holders424as first support members for fixing the plurality of stator cores123. The core holder integrated casing428is formed by integrating the coil holder429and the plurality of core holders424. The core holder integrated casing428is formed by a nonmagnetic material. More preferably, the core holder integrated casing428is formed by an electrically insulating nonmagnetic material. Note that at least one of the core holders424may also be a member different from the core holder integrated casing428. This core holder424is fixed to the coil holder429in a contact state by using a method such as bolt fastening or adhesion. More preferably, the core holder424is formed by integration processing.

The armature coil122is wound around the coil holder429, and fixed to the coil holder429in a contact state. The coil holder429forms a third support member for fixing the armature coil122in a contact state. Each core holder424includes a pair of core holder parts424A and424B opposing each other with the coil holder429being interposed between them. The core holder part424A is formed on one end face of the coil holder429, and the core holder part424B is formed on the other end face of the coil holder429. The core holder parts424A and424B have an approximately square pillar shape which narrows toward the rotor element110. The width of the core holder424in the rotation direction decreases toward the rotor element110. The sectional shape of the core holder424in a plane perpendicular to a rotation axis z is an approximate fan shape or trapezoidal shape. In the example shown inFIG. 18, the number of stator cores123is 24, and the number of core holders424is 12. The core holders424are arranged at a circumferential pitch of 30 degrees. The number of core holders424changes in accordance with the number of stator cores123.

As shown inFIG. 16, the core holder424is placed between two adjacent stator cores123. The core holder parts424A and424B respectively come in contact with magnetic pole parts123A and123B of the stator core123. The plurality of core holders424and the plurality of wedge members125are alternately arranged between the stator cores123, and the plurality of stator cores123, the plurality of core holders424, and the plurality of wedge members125form an integrated annular body as a whole.

A casing for housing the armature420can be the casing121according to the first embodiment. The armature420can be fixed to the casing121by the same method as explained in the first embodiment, specifically, by bolt fastening. Furthermore, the wedge member125is pressed toward the rotor element110by the same method as explained in the first embodiment, specifically, by using a screw. Consequently, preloads containing rotation-direction components and opposite to each other are applied to two stator cores123in contact with the wedge member125.

In the electric rotating machine according to this embodiment as described above, the armature coil122is wound around the coil holder429integrated with the core holder424. Accordingly, heat generated by a copper loss of the armature coil122caused when an electric current is supplied is transferred from the coil holder429to the core holder424by heat conduction, and extracted from the core holder424. As a consequence, it is possible to more effectively remove heat generated by a copper loss. In addition, the rigidity for supporting the stator core123can be improved as in the first embodiment.

Fifth Embodiment

In the fifth embodiment, an explanation of the same parts as in the first embodiment will be omitted as needed, and the explanations will focus on those parts different from the first.

FIG. 19schematically shows an electric rotating machine500according to the fifth embodiment. As shown inFIG. 19, the electric rotating machine500includes a rotor101supported by a bearing (not shown) so as to be rotatable around a rotation axis z, and a stator502which opposes the outer circumferential surface of the rotor101with a predetermined gap between them. The stator502has an approximately cylindrical shape coaxial with the rotation axis z. The rotor101is positioned inside the stator502.

FIGS. 20A and 20Bare respectively a perspective view and front view schematically showing the stator502, andFIG. 21is a partially exploded view schematically showing the stator502. The electric rotating machine500is a three-stage (three-phase) electric rotating machine in which three basic units are arranged in the rotation-axis direction. As shown inFIG. 21, each basic unit includes one rotational element (not shown), and one armature520opposing the rotational element. Note that the number of basic units is determined in accordance with the design conditions, and can be an arbitrary integer that is two or more.

The armature520includes an armature coil122, a plurality of stator cores123, and a plurality of wedge members125. The plurality of stator cores123and the plurality of wedge members125are alternately arranged, and form an integrated annular body as a whole. Specifically, as shown inFIG. 20B, the plurality of stator cores123and the plurality of wedge members125are arranged in the order of a stator core123-1, wedge member125-1, stator core123-2, wedge member125-2, stator core123-3, and so on. In the example shown inFIG. 20B, the number of stator cores123is 24, and the number of wedge members125is 24. In this case, the stator cores123are arranged at a circumferential pitch of 15 degrees, and the wedge members125are arranged at a circumferential pitch of 15 degrees.

Note that the explanation has been made by taking the case in which the number of stator cores123included in each armature520is 24 as an example. However, the number of stator cores123is not limited to that of this example, and an optimum number can be selected in accordance with the designed specifications of an application device. The number of wedge members125changes in accordance with the number of stator cores123.

As shown inFIG. 20A, the stator502further includes an approximately annular or cylindrical casing521having a half-split structure. The material of the casing521can be any material which satisfies the mechanical strength required of the electric rotating machine500. The casing521includes casing parts521A and521B. The casing parts521A and521B are arranged so as to cover the armature520around the rotation axis z, and fastened by bolts530and nuts531. Specifically, as shown inFIG. 21, a plurality of through holes526are formed in the upper and lower end parts of the casing part521A and in the upper and lower end parts of the casing part521B, and the bolts530are inserted through the through holes526in the casing parts521A and521B, and threadably engaged with the nuts531. In this state, the inner circumferential surfaces of the casing parts521A and521B come in contact with an outer circumferential surface125D of the wedge member125, so the casing parts521A and521B apply a preload containing a rotation-direction component pointing to the rotation axis to the wedge member125. Consequently, preloads containing rotation-direction components are applied to two stator cores123in contact with the wedge member125. The two stator cores123receive preloads in opposite directions.

In the electric rotating machine500according to this embodiment, the plurality of stator cores123and the plurality of wedge members125come in contact with each other and form an integrated annular body as a whole, and the casing521applies a preload containing a radial-direction component pointing to the rotation axis z to the wedge member125. This structure improves the rigidity for supporting the stator core123. As a result, it is possible to reduce vibrations generated when the electric rotating machine500is driven. Since the generation of vibrations is reduced, the generation of noise caused by the vibrations can be reduced as well, so it is possible to prevent a decrease in strength caused by the vibrations. Furthermore, this embodiment can be practiced without any core holders, so the types of components can be reduced. This makes it possible to simplify the structure, improve the ease of assembly, and reduce the cost.

At least one of the above-described embodiments can improve the rigidity for supporting the stator cores by forming the wedge member between the stator cores. In the following sixth to eighth embodiments, application examples of the electric rotating machines according to the above-described embodiments will be explained.

Sixth Embodiment

FIG. 22schematically shows an electrically driven vehicle600according to the sixth embodiment. The electrically driven vehicle600includes one of the electric rotating machines described in the first to fifth embodiments, or a modification thereof. In this example shown inFIG. 22, the electrically driven vehicle600includes the electric rotating machine100according to the first embodiment. The electrically driven vehicle600is a so-called hybrid electric vehicle (HEV). A body601of the electrically driven vehicle600is supported by two front wheels602and two rear wheels620. The front wheels602are connected to the electric rotating machine100by driving shafts603, a differential gear604, and a driving shaft605. The driving shaft605is connected to the rotor101(not shown inFIG. 22) of the electric rotating machine100. The rotor101is rotatably supported by bearings606arranged on the two sides of the electric rotating machine100. The electrically driven vehicle600further includes an engine607, and the engine607is connected to the rotor101by a connecting shaft608. Accordingly, both the torque of the engine607and the torque of the electric rotating machine100are transmitted to the front wheels602, and function as a force of driving the body601.

FIG. 23shows details of a part of the electrically driven vehicle600including the electric rotating machine100in an enlarged scale. As shown inFIG. 23, the power lines of outputs u, v, and w of a controller610that operates by using a battery609as a power supply are connected to the armature coil122of the electric rotating machine100. The controller610applies three-phase electric currents having phase differences of 120° to the armature coil122of the electric rotating machine100. The controller610operates so that the electric rotating machine100functions as a generator when collecting regenerative energy obtained when the body601changes from a running state to a stopped state.

In the electrically driven vehicle600using the electric rotating machine100, vibrations and noise generated when the electric rotating machine100operates as a motor and generator are reduced, so the energy conversion efficiency can be improved. In addition, the fuel consumption of the engine607can be reduced by using the small-sized, high-output electric rotating machine100. Consequently, the mileage efficiency can be improved.

The electrically driven vehicle is not limited to the hybrid electric vehicle as shown inFIG. 22, and may also be an electric vehicle (EV). The mileage efficiency can be improved even when the electric rotating machine according to an embodiment (for example, the electric rotating machine100) is applied to the electric vehicle.

Seventh Embodiment

FIG. 24schematically shows a wind turbine generator700according to the seventh embodiment. The wind turbine generator700includes one of the electric rotating machines described in the first to fifth embodiments, or a modification thereof. In this example shown inFIG. 24, the wind turbine generator700includes the electric rotating machine100according to the first embodiment. Blades701of the wind turbine generator700rotate by wind power, and transmit the torque to a speed increaser703via a rotating shaft702. The output torque from the speed increaser703is transmitted to the rotor101(not shown inFIG. 24) of the electric rotating machine100via a rotating shaft704and shaft coupling705, and the electric rotating machine100generates electric power. The generated electric power is supplied to a power system708via a transformer706and system protector707.

Rotary system main parts including the speed increaser703and electric rotating machine100are housed in a machine room called a nacelle709. The nacelle709is supported by a tower710so that the blades701are positioned at a height at which wind power can efficiently be obtained. The tower710is fixed on a base711installed on the ground or on a floating body on the sea.

In the wind turbine generator700using the electric rotating machine100, vibrations and noise generated when the electric rotating machine100operates can be reduced. This makes it possible to reduce energy that is lost as vibrations and noise, and to efficiently convert wind power into power generation energy. In addition, the use of the small-sized, high-output electric rotating machine100makes it possible to reduce the size and weight of the nacelle709, and relax the design conditions of the mechanical strength required of the tower710. As a result, it is possible to reduce the construction cost and construction period of the tower710, and reduce the overall cost of the wind turbine generator700. When the wind turbine generator700is a floating offshore wind turbine generator in which the base711is installed on a floating body on the sea, it is possible to reduce the ocean transport cost of the nacelle709, and reduce the floating body construction cost and construction period of the base711, thereby reducing the overall cost of the wind turbine generator700.

Note that the electric rotating machines according to the embodiments can be used not only for the wind turbine generator, but also for general power generators such as a hydroelectric generator. Even when applying the electric rotating machines according to the embodiments to a power generator other than the wind turbine generator, it in possible to suppress a power generation loss caused by vibrations and noise, and to improve the power generation efficiency.

Eighth Embodiment

FIG. 25schematically shows a rope elevator device800according to the eighth embodiment. The elevator device800includes one of the electric rotating machines described in the first to fifth embodiments, or a modification thereof. In this example shown inFIG. 25, the elevator device800includes the electric rotating machine300according to the third embodiment.

The elevator device800includes a winding machine801, cage802, counterweight803, and rope804, and is installed in a hoistway807. The winding machine801includes the electric rotating machine300and a sheave. The rope804is wound around a pulley805of the cage802, the winding machine801, and a pulley806of the counterweight803. One end of the rope804is fixed to a predetermined position A of a building or the like, and the other end of the rope804is fixed to a predetermined position B of the building or the like. When a controller (not shown) drives the winding machine801, a torque generated by the electric rotating machine300rotates the sheave. The winding machine801can move the cage802upward or downward by winding up or down the rope804by using the frictional force between the sheave and rope804.

In the elevator device800using the electric rotating machine300, vibrations and noise generated when the electric rotating machine300operates can be reduced, so the energy conversion efficiency can be improved. Also, when the vibrations of the electric rotating machine300as a torque generation source of the winding machine801are reduced, vibrations transmitted to the cage802via the rope804are also reduced. The ride comfort of the elevator device800can be improved. Furthermore, it is possible to reduce vibrations and noise transmitted outside the hoistway807.

Note that in the sixth to eighth embodiments, examples in which the electric rotating machines according to the embodiments are applied to an electrically driven vehicle, power generator, and elevator device have been explained. However, the electric rotating machines according to the embodiments are also applicable to devices other than the electrically driven vehicle, power generator, and elevator device.