TECHNICAL FIELD

The present invention relates to a coreless rotating electrical machine for being operated under a load exceeding a rating, a driving method thereof, and a driving system including thereof.

More specifically, the present invention relates to a coreless rotating electrical machine, a driving method thereof, and a driving system including thereof, in which an air space including an air gap is formed by a stator consisting of a lid-type mount which fixes an end face of an energizable coreless cylindrical coil and a rotor consisting of a cylindrical or cup-type mount opposingly and rotatably positioned with respect to the lid-type mount with a plurality of magnets equipped on an inner surface of the cylindrical mount, and when it is to be operated under the load exceeding the rating, such operation is enabled by adjusting supply amount of the refrigerant liquid so that the temperature of the cylindrical coil does not exceed the allowable maximum temperature at a rated operation, in which the refrigerant liquid is supplied to the air space to allow the cylindrical coil, which generates heat, to vaporize the refrigerant liquid so as to cool itself by latent heat of vaporization of the refrigerant liquid.

BACKGROUND ART

An electric motor and an electric generator are both a rotating electrical machine having a same structure. Descriptions are made for the rotating electrical machine using the electric motor which converts electrical energy to kinetic energy. The electric motor outputs electromagnetic power generated by an interaction of a magnetic field and electricity. There are various methods of classification, but generally they are classified as a DC motor with brush or a brushless motor, wherein the former uses a magnet as a stator, coil as a rotor, and conversely, the latter uses a coil as a stator, a magnet as a rotor, and each of them is what outputs electromagnetic power to outside from the rotor. On the other hand, the electric is also classified as a winding-field type or a permanent-magnet type depending on a difference in generating the magnetic field, and is also classified based on whether a coil is with or without a core. According to the classification described in the above, the subject of the present invention is a permanent-magnet field type coreless brushless electric motor.

The present invention relates to a coreless brushless motor consisting of a permanent-magnet field type coreless cylindrical coil. The coreless cylindrical coil of a stator is either made with a laminate of electrically conductive metal sheets having linear parts covered with insulating layers, or made with a linear conductor covered with an insulating layer.

The electric motor may momentarily exceed a rated current at start-up, but it is not assumed to be continuously operated under a condition exceeding a rating. When the electric motor is continuously operated under an overload condition, that is, continuously operated above the rating, the cylindrical coil of the electric motor generates heat more than assumed by electric current applied.

Though it depends on structures and functions of the electric motor, when overload tests are performed under each of conditions exceeding the rating, using a coreless motor (CP50) manufactured as a test motor related to the present invention, without activating a controlling part of a refrigerant liquid supply, an allowable maximum temperature of the cylindrical coil, which is 130° C., is exceeded in only a few tens of seconds, as described in the followings. The worst state which may be easily assumed to be caused from the above is that the cylindrical coil burns out and be destructed. Even if the cylindrical coil does not result in destruction, it is no longer possible to expect a normal long-time operation of the coreless motor in the context of performance. It has been well-known without mentioning, and it is merely a commonly used means to add a cooling function to the electric motor in order to prevent a decrease in performance of the electric motor accompanied with heat generation of the cylindrical coil and/or heating of the magnet.

In spite of existence and non-existence of such cooling function, a maximum temperature limit for a coil and/or magnets during a normal operation of an electric motor is shown as a rating from a manufacturer (page 41 of Non-Patent Document 1). The rating is a unique standard guaranteed by the manufacturer, and is described in catalogs and/or specifications, it means that, for example, the maximum output from the motor at a predetermined voltage, with the motor exerting a good property, becomes a rated output, a rotating speed when operated under the rated output is a rated rotating speed, a torque T at such time is a rated torque, and a current at such time is a rated current. When usage is not specified, a continuous rating which allows an operation for an indefinite period of time is provided as the rating. As other ratings, there are a short-time rating in which an operational period is limited and/or an intermittent-service rating in which an operation is repeatedly made on and off periodically etc.

The present invention relates to a coreless motor for being operated under a load exceeding a rating, which is developed based on an idea of enabling a constant operation under overload. The term “rating” described herein refers to, for example, a rating when the coreless motor is operated at a predetermined voltage under a rated torque or a rated output.

In this regard, the coreless motor (CP50) manufactured as a test motor is a so-called electric motor. While details will be described in the followings, conditions of the rating described here are that, a continuous operation is performed with the refrigerant supply amount being zero, and without activating the controlling part of the refrigerant supply, and also that the temperature of the cylindrical coil does not exceed the allowable maximum temperature which is 130° C., wherein the rated torque is T0=0.28 Nm, the rated current is I0=9.7 Arms, the rated rotating speed is n0=6537 rpm and the rated output is P0=191.67 W (FIG. 11).

Next, it has been well-known to add a cooling function to an electric motor in order to prevent decrease in performance of the electric motor accompanied with heat generation of a cylindrical coil and/or heating of a magnet. This is appreciated from the following conventional techniques.

Patent Document 1 (PCT Japanese Publication: JP2012-523817A) describes as that, a diffusive material is disposed around coils, which absorbs a liquid coolant having a boiling point below a working temperature of the coils to make the coil wet so that the coils are cooled by heat of vaporization of the boiled liquid coolant.

Patent Document 2 (Japanese Laid-Open Patent Publication H10-336968A) describes a system, including a radiator, configured such that a centrifugal pump action of a rotor and height difference are used for refrigerant circulation of a gas-liquid two-phase so that inside of a rotating electrical appliance for vehicle is cooled.

Patent Document 3 (Japanese Laid-Open Patent Publication 2006-14522A) describes storing a refrigerant, which temperature of a boiling point is lower than an allowable maximum temperature, in an electric generator, and efficiently cooling the electric generator while alternatively repeating vaporizing of the refrigerant and devolatilizing of the refrigerant inside the electric generator during operation of the electric generator.

Patent Document 4 (Japanese Laid-Open Patent Publication 2006-158105A) describes evaporating a coolant in a liquid phase in an auto-circulating path including a reservoir tank of the coolant with heat generated from a rotor to allow for efficient cooling with the evaporated coolant.

Patent Document 5 (Japanese Laid-Open Patent Publication 2009-118693A) describes a method for cooling a rotor with latent heat of vaporization, in which, in a rotor cooling apparatus, a refrigerant is continuously supplied little by little toward a cooling wall surface of the rotor such that the refrigerant may not be located eccentrically on the wall.

Patent Document 6 (Japanese Laid-Open Patent Publication 2015-95961A) describes a cooling structure of a motor in which, in a sealed case of the motor, a refrigerant included in the case is vaporized by heat of a coil of a stator, devolatilized in a heat releasing part and circulated in the sealed case. This cooling structure is common with what are described in Patent Documents 3 and/or 4.

Patent Document 7 (Japanese Laid-Open Patent Publication 2009-118686A) describes a cooling structure of a rotating electrical appliance in which a refrigerant distribution channel for cooling magnets and that for cooling a coil is respectively provided, and the channels are arranged with a switchable means.

Patent Document 8 (Japanese Laid-Open Patent Publication 2014-17968A) describes a cooling system of a rotating electrical appliance mounted on a hybrid vehicle. The rotating electrical appliance comprises a coil part which winds around a stator core formed by laminating a plurality of electromagnetic steel plates. The cooling system of the rotating electrical apparatus having an iron core disclosed therein is configured such that, when a temperature of windings of the coil part exceeds 180° C. for more than 10 times, an insulated covering around the windings of the coil part evaporates or vaporizes and be dissipated to result in a decrease in performance for withstanding discharge pressure, and thus, a controlling part is equipped for adjusting supply amount of a refrigerant to form a state where the refrigerant is adhered around the windings of a specific portion so as to prevent such decrease in performance.

Patent Document 9 (Japanese Laid-Open Patent Publication H06-217496A) describes an electric generator in which an evaporative condensation room is provided inside a rotor of the electric generator, a cooling liquid is fed with a jet stream from outside in an axial direction, and an impeller for waste liquid is provided in a liquid room connected with a cooling liquid room which uses centrifugal force to deflect the cooling liquid to the evaporative condensation room side to make it flow.

Patent Document 10 (Japanese Laid-Open Patent Publication H05-308752A) describes a radiating structure of a motor placed in a housing where a rotor and an annular stator surrounding the rotor are in an air tight state, in which a pipe in communication with an annular cavity in the housing to which a working fluid is included, and a Whitworth having a capillary action are arranged.

Patent Document 11 (Japanese Laid-Open Patent Publication H08-130856A) describes a cooling circuit, in which, in a driving device motor for electric vehicle consisting of a coil winded on a cylindrical core, oil is dropped on a coil end from a cooling oil pump via a cooling oil injection part.

CITATION LIST

Patent Documents

Patent Document 1: PCT Japanese Publication: JP2012-523817A

Patent Document 2: Japanese Laid-Open Patent Publication H10-336968A

Patent Document 3: Japanese Laid-Open Patent Publication 2006-14522A

Patent Document 4: Japanese Laid-Open Patent Publication 2006-158105A

Patent Document 5: Japanese Laid-Open Patent Publication 2009-118693A

Patent Document 6: Japanese Laid-Open Patent Publication 2015-95961A

Patent Document 7: Japanese Laid-Open Patent Publication 2009-118686A

Patent Document 8: Japanese Laid-Open Patent Publication 2014-179681A

Patent Document 9: Japanese Laid-Open Patent Publication H06-217496A

Patent Document 10: Japanese Laid-Open Patent Publication H05-308752A

Patent Document 11: Japanese Laid-Open Patent Publication H08-130856A

Non-Patent Documents

Non-Patent Document 1: “Best Colored Illustration, All of Current Motor Technology”, Edited by Kan Akatsu, Natsume Publishing Planning Co., Ltd. (Published on Jul. 20, 2013)

SUMMARY OF INVENTION

Technical Problem

A technical problem inherent in an electric motor, which is rotated by electromagnetic action of components such as a stator and a rotor, is heat generation action of a coil which is an armature equipped, on the stator. Performance and/or size of the electric motor are generally represented by output of the electric motor. The output P0is represented by the product of rotating speed n (rpm) and torque T (N·m). Provided that input power of the electric motor is P1(W), a difference between the input power P1and the output P0is converted to heat energy as heat loss PLand discharged to the environment. This is the heat generation action of the armature coil, and is the technical problem of the electric motor which is difficult to be avoided. For example, not applied only to a coreless motor, it has been a well-known matter for those skilled in the art that, when the electric motor is continued to be operated under the load exceeding the rating, an allowable maximum temperature of the armature coil is exceeded in a short time due to such heat generation action, resulting in burnout and destruction. There is also a problem inherent in the electric motor that the heat generation action of the armature coil raises a resistance value of the armature coil, and evokes output fluctuation of the electric motor, and thus, it is also an ultimate technical problem of the electric motor to completely control the temperature of the armature coil in a certain range so as to minimize the output fluctuation.

The problem may be solved by finding a way to control the temperature of the armature coil. Various proposals as described in the above have been made to address the problem but have not led to a fundamental solution for the ultimate problem of completely controlling the temperature of the armature coil in the certain range.

Solution to Problem

However, the inventors have challenged to develop an electric motor based on the idea of enabling the constant operation under overload, and realized a coreless rotating electrical machine for being operated under a load exceeding a rating, a method for driving thereof, and a driving system including thereof, and came up with solving the technical problem. This can be confirmed from driving tests using a coreless motor (CP50) manufactured based on one embodiment of the present invention.

The voltage of the coreless motor (CP50) is set to 24 V, and measured the torque. This is the rated torque T0=0.28 Nm. The inventors of the present invention have confirmed that a long time operation of the coreless motor (CP50) is possible by completely controlling the heat generation of the cylindrical coil, which is the armature coil, with a load exceeding the rated torque T0being continuously applied to the coreless motor (CP50).

The first aspect of the present invention is a coreless rotating electrical machine10for being operated under a load exceeding a rating, shown in a cross sectional schematic diagram ofFIG. 1and a broken perspective diagram ofFIG. 2.

It is the coreless rotating electrical machine10in which an air space40including an air gap is formed by a stator2consisting of a lid-type mount200which fixes an end face101of an energizable coreless cylindrical coil100and a rotor3consisting of a cylindrical mount300opposingly and rotatably positioned with respect to the lid-type mount200with a plurality of magnets4equipped on an inner surface310of the cylindrical mount300; a channel8for supplying a refrigerant liquid80to the air space40is provided on the stator2; and a controlling part20related to the stator2and a driving part30related to the rotor3are equipped therewith.

It can also be equipped, on the stator2, with a refrigerant liquid container81which is in communication with the channel8, and a circulating means82which communicates between the refrigerant liquid container81and the air space40.

As apparent from the first aspect of the present invention, the coreless rotating electrical machine10is characterized in that, the driving part30is activated, and when it is to be operated under the load exceeding the rating, such operation is enabled by activating the controlling part20to adjust supply amount of the refrigerant liquid80so that the temperature of the cylindrical coil100does not exceed the allowable maximum temperature tMat a rated operation, in which the refrigerant liquid80is supplied to the air space40to allow the cylindrical coil100, which generates heat, to vaporize the refrigerant liquid80so as to cool itself by latent heat of vaporization of the refrigerant liquid80.

As one embodiment of the present invention, it is more preferable that, when the cureless rotating electrical machine10is operated under the load exceeding the rating, an operation of activating the controlling part20to adjust supply amount of the refrigerant liquid80so that the temperature of the cylindrical coil100does not exceed the allowable maximum temperature tM, and an operation to stop supplying of the refrigerant liquid80to the air space40so that the temperature of the cylindrical coil100at least does not fall below the minimum temperature tNwhere the refrigerant liquid80vaporizes by the above operation are repeated so as to maintain the temperature of the cylindrical coil100in a range between the allowable maximum temperature tMand the minimum temperature tN.

As another embodiment of the present invention, as shown in a schematic diagram ofFIG. 5, the controlling part20may comprise a coil temperature detecting sensor21for detecting a temperature of the cylindrical coil100, a pump22for supplying the refrigerant liquid80to the air space40in coordination with the coil temperature detecting sensor21, and a controller23for adjusting supply amount of the refrigerant liquid80with on/off command to the pump22.

As a further embodiment of the present invention, as shown in a schematic diagram ofFIG. 6, the controlling part20may comprise a coil temperature detecting sensor21for detecting a temperature of the cylindrical coil100, an electromagnetic valve24for supplying the refrigerant liquid80to the air space40from the refrigerant liquid container81arranged at a position higher than the cylindrical coil100, in coordination with the coil temperature detecting sensor21, and a controller23for adjusting supply amount of the refrigerant liquid80with open/close command to the electromagnetic valve24.

As another embodiment of the present invention, as shown inFIG. 5orFIG. 6, the controlling part20may be configured such that the refrigerant liquid80in a gas phase800is collected in a liquid phase80into the refrigerant liquid container81by a circulating means82.

As a further embodiment of the present invention, as shown inFIGS. 1 and 2, the coreless rotating electrical machine10may be configured such that a drive shaft1000is equipped as being fixed to a center part340of the cylindrical mount300, and rotatably coupled to a center part240of the lid-type mount200.

The second aspect of the present invention is a coreless rotating electrical machine10for being operated under a load exceeding a rating shown in a cross sectional schematic diagram ofFIG. 3and a broken perspective diagram ofFIG. 4.

It forms a first air space40including an air gap by a stator2consisting of a lid-type mount200which fixes one of end faces101of an energizable coreless cylindrical coil100, and a rotor3consisting of a cup-type mount400opposingly and rotatably positioned with respect to the lid-type mount200, wherein the cup-type mount400included in the rotor3has a bottom part410open at one end and closed at the other end, to which concentric inner yoke420and outer yoke430are integrated, and the rotor is equipped with a plurality of magnets4with intervals with respect to each other in a circumferential direction on an outer surface422of the inner yoke420and/or an inner surface431of the outer yoke430, and provided with slits423, each of which passing through the inner yoke420, at positions of the inner yoke420corresponding to each of the intervals41.

Further, it is the coreless rotating electrical machine10for being operated under the load exceeding the rating, in which the cylindrical coil100is arranged in a first air space40as suspended such that the other end face102of the cylindrical coil100leaves a clearance411between the bottom410of the cup-type mount400; a second air space50is formed between one of end faces401of the cup-type mount400and the lid-type mount200at an inner periphery side110of the cylindrical coil100; a third air space60is formed at an outer periphery side120of the cylindrical coil100; a channel8for supplying a refrigerant liquid80to the first air space40is provided on the stator2; and a controlling part20related to the stator2, and a driving part30related to the rotor3are equipped therewith.

It also can be equipped, on the stator2, with a refrigerant liquid container81which is in communication with a channel8, and further equipped with a circulating means82which communicates between the refrigerant liquid container81and the first air space40.

As apparent from the second aspect of the present invention, the coreless rotating electrical machine10is characterized in that, the driving part30is activated, and when it is to be operated under the load exceeding the rating, such operation is enabled by activating the controlling part20to adjust supply amount of the refrigerant liquid80so that the temperature of the cylindrical coil100does not exceed the allowable maximum temperature tMat a rated operation, in which the refrigerant liquid80is supplied to inside421of the inner yoke420of the first air space40to allow the cylindrical coil100, which generates heat, to vaporize the refrigerant liquid80fed be cylindrical coil100via the slits423so as to cool itself by latent heat of vaporization of the refrigerant liquid80.

As one embodiment of the present invention, it is more preferable that, when the coreless rotating electrical machine10is operated under the load exceeding the rating, an operation of activating the controlling part20to adjust supply amount of the refrigerant liquid80so that the temperature of the cylindrical coil100does not exceed the allowable maximum temperature tM, and an operation of stop supplying of the refrigerant liquid80to the air space40so that the temperature of cylindrical coil100does not fall below the allowable minimum temperature tNwhere the refrigerant liquid80vaporizes by the above operation are repeated so as to maintain the temperature of the cylindrical coil100in a range between the allowable maximum temperature tMand the allowable minimum temperature tN.

As another embodiment of the present invention, as shown in a schematic diagram ofFIG. 5, the controlling part20may comprise a coil temperature detecting sensor21for detecting a temperature of the cylindrical coil100, a pump22for supplying the refrigerant liquid80to inside421of the inner yoke420of the first air space40in coordination with the coil temperature detecting sensor21, and a controller23for adjusting the supply amount of the refrigerant liquid80with on/off command to the pump22.

As a further embodiment of the present invention, as shown in a schematic diagram ofFIG. 6, the controlling part20may comprise a coil temperature detecting sensor21for detecting a temperature f the cylindrical coil100, an electromagnetic valve24for supplying the refrigerant liquid80to inside421of the inner yoke420of the first air space40from the refrigerant liquid container81arranged at a position higher than the cylindrical coil100, in coordination with the coil temperature detecting sensor21, and a controller23for adjusting supply amount of the refrigerant liquid80with open/close command to the electromagnetic valve24.

As another embodiment of the present invention, as shown inFIG. 5ofFIG. 6, the controlling part20may be configured such that the refrigerant liquid80in a gas phase800is collected in a liquid phase80into the refrigerant liquid container81by a circulating means82.

As a further embodiment of the present invention, as shown inFIGS. 3 and 4, the coreless rotating electrical machine10may be configured such that a drive shaft1000is equipped as being fixed to a center part340of the cup-type mount400, and rotatably coupled to a center part240of the lid-type mount200.

As one embodiment in the first and second aspects of the present invention, it is preferred that the cylindrical coil100is made from what formed to a cylindrical form by either of a laminate of electrically conductive metal sheets having linear parts being spaced in an axial direction covered with insulating layers, or a linear conductor covered with an insulating layer.

As another embodiment in the first and second aspects of the present invention, it is preferred that the refrigerant liquid80is any of water, ethanol, ammonia, liquid nitrogen, liquid helium or fluorinated liquid.

The third aspect of the present invention is a driving method of a coreless rotating electrical machine10for being operated under a load exceeding a rating, shown inFIG. 1andFIG. 2.

It is the driving method of the coreless rotating electrical machine10for being operated under a load exceeding a rating, in which an air space40including an air gap is formed by a stator2consisting of a lid-type mount200which fixes an end face101of an energizable coreless cylindrical coil100and a rotor3consisting of a cylindrical mount300opposingly and rotatably positioned with respect to the lid-type mount200with a plurality of magnets4equipped on an inner surface310of the cylindrical mount300; a channel8for supplying a refrigerant liquid80to the air space40is provided on the stator2; and a controlling part20related to the stator2and a driving part30related to the rotor3are equipped therewith.

Further, in the driving method of the present invention, the coreless rotating electrical machine10can also be equipped, on the stator2, with a refrigerant liquid container81which is in communication with the channel8, and a circulating means82which communicates between the refrigerant liquid container81and the air space40.

As apparent from the third aspect of the present invention, the method is characterized in that it comprises: a step of activating the driving part30and operating the coreless rotating electrical machine10under the load exceeding the rating; a step of activating the controlling part20to supply the refrigerant liquid80to the air space40; a step of allowing the cylindrical coil100, which generates heat, to vaporize the refrigerant liquid80so as to cool itself by latent heat of vaporization of the refrigerant liquid80; and a step of adjusting supply amount of the refrigerant liquid80so that the temperature of the cylindrical coil100does not exceed the allowable maximum temperature tMat a rated operation.

As one embodiment of the present invention, further, it is more preferable to comprise a step of activating the controlling part20to stop supplying of the refrigerant liquid80to the air space40so that the temperature of the cylindrical coil100at least does not fall below the minimum temperature tNwhere the refrigerant liquid80vaporizes, and further comprise a step of repeating the above step and the step of supplying the refrigerant liquid80to the air space40so as to maintain the temperature of the cylindrical coil100in a range between the allowable maximum temperature tMand the minimum temperature tN.

As another embodiment of the present invention, it may be the driving method, in which, as shown inFIG. 5, the controlling part20further comprises a coil temperature detecting sensor21for detecting a temperature of the cylindrical coil100, a pump22for supplying the refrigerant liquid80, and a controller23for adjusting supply amount of the refrigerant liquid80with on/off command to the pump22, and the method comprises a step of activating the coil temperature detecting sensor21to detect a temperature of the cylindrical coil100, a step of having the controller23activate the pump22in coordination with the above step to supply the refrigerant liquid80to the air space40, and a step of adjusting supply amount of the refrigerant liquid80.

As a further embodiment of the present invention, it also may be the driving method, in which, as shown inFIG. 6, the controlling part20comprises a coil temperature detecting sensor21for detecting a temperature of the cylindrical coil100, an electromagnetic valve24for supplying the refrigerant liquid80to the air space40from the refrigerant liquid container81arranged at a position higher than the cylindrical coil100, in coordination with the coil temperature detecting sensor21, and a controller23for adjusting supply amount of the refrigerant liquid80with open/close command to the electromagnetic valve24, and the method comprises a step of activating the coil temperature detecting sensor21to detect a temperature of the cylindrical coil100, a step of having the controller23activate the electromagnetic valve24in coordination with the above step to supply the refrigerant liquid from the refrigerant liquid container81to the air space40, and a step of adjusting supply amount of the refrigerant liquid80.

As another embodiment of the present invention, further, as shown inFIG. 5orFIG. 6, it also may be the driving method which further comprises a step of having the controlling part20activate the circulating means82to collect the refrigerant liquid80in a gas phase800into the refrigerant liquid container81in a liquid phase80thereof.

As another embodiment of the present invention, further, it also may be the driving method of the coreless rotating electrical machine10in which a drive shaft1000is fixed to a center part340of the cylindrical mount300, and rotatably coupled to a center part240of the lid-type mount200.

The fourth aspect of the present invention is a driving method of a coreless rotating electrical machine10for being operated under a load exceeding a rating, shown inFIG. 3andFIG. 4.

The coreless rotating electrical machine10forms a first air space40including an air gap by a stator2consisting of a lid-type mount200which fixes one of end faces101of an energizable coreless cylindrical coil100, and a rotor3consisting of a cup-type mount400opposingly and rotatably positioned with respect to the lid-type mount200, wherein the cup-type mount400included in the rotor3has a bottom part410open at one end and closed at the other end, to which concentric inner yoke420and outer yoke430are integrated, and the rotor is equipped with a plurality of magnets4with intervals41with respect to each other in a circumferential direction on an outer surface422of the inner yoke420and/or an inner surface431of the outer yoke430, and provided with slits423, each of which passing through the inner yoke420, at positions of the inner yoke420corresponding to each of the intervals41.

Further, it is the driving method for operating the cureless rotating electrical machine10under the load exceeding the rating, in which the cylindrical coil100is arranged in a first air space40as suspended such that the other end face102of the cylindrical coil100leaves a clearance411between the bottom410of the cup-type mount400; a second air space50is formed between one of end faces401of the cup-type mount400and the lid-type mount200at an inner periphery side110of the cylindrical coil100; a third air space60is formed at an outer periphery side120of the cylindrical coil100; a channel8for supplying a refrigerant liquid80to the first air space40is provided on the stator2, and a controlling part20related to the stator2, and a driving part30related to the rotor3are equipped therewith.

Further, in the driving method of the present invention, the coreless rotating electrical machine10can be equipped, on the stator2, with a refrigerant liquid container81which is in communication with a channel8, and further equipped with a circulating means82which communicates between the refrigerant liquid container81and the first air space40.

As apparent from the fourth aspect of the present invention, the method is characterized in that it comprises a step of activating the driving part30and operating the coreless rotating electrical machine10under the load exceeding the rating, a step of activating the controlling part20to supply the refrigerant liquid80to inside421of the inner yoke420of the first air space40so as to feed the refrigerant liquid80to the cylindrical coil100, which generates heat, via the slits423, a step of allowing the cylindrical coil100, which generates heat, to vaporize the refrigerant liquid80so as to cool itself by latent heat of vaporization of the refrigerant liquid80, and a step of adjusting supply amount of the refrigerant liquid80so that the temperature of the cylindrical coil100does not exceed the allowable maximum temperature tMat a rated operation.

As one embodiment of the present invention, further, it is preferable to comprise a step of activating the controlling part20to stop supplying of the refrigerant liquid80to the first air space40so that the temperature of the cylindrical coil100at least does not fall below the minimum temperature tNwhere the refrigerant liquid80vaporizes, and further comprise a step of repeating the above step and the step of supplying the refrigerant liquid80to inside421of the inner yoke420of the first air space40so as to feed the refrigerant liquid80to the cylindrical coil100, which generates heat, via the slits423so as to maintain the temperature of the cylindrical coil100in a range between the allowable maximum temperature tMand the minimum temperature tN.

As another embodiment of the present invention, it may be the driving method, in which as shown in a schematic diagram ofFIG. 5, the controlling part20further comprises a coil temperature detecting sensor21for detecting a temperature of the cylindrical coil100, a pump22for supplying the refrigerant liquid80, and a controller23for adjusting supply amount of the refrigerant liquid80with on/off command to the pump22, and the method comprises a step of activating the coil temperature detecting sensor21to detect a temperature of the cylindrical coil100, a step of having the controller23activate the pump22in coordination with the above step to supply the refrigerant liquid80to inside421of the inner yoke420of the first air space40so as to feed the refrigerant liquid80to the cylindrical coil100, which generates heat, via the slits423, and a step of adjusting supply amount of the refrigerant liquid80.

As a further embodiment of the present invention, it also may be the driving method, in which, as shown in a schematic diagram ofFIG. 6, the controlling part20comprises a coil temperature detecting sensor21for detecting a temperature of the cylindrical coil100, an electromagnetic valve24for supplying the refrigerant liquid80to the first air space40from the refrigerant liquid container81arranged at a position higher than the cylindrical coil100, in coordination with the coil temperature detecting sensor21, and a controller23for adjusting supply amount of the refrigerant liquid80with open/close command to the electromagnetic valve24, and the method comprises a step of activating the coil temperature detecting sensor21to detect a temperature of the cylindrical coil100, a step of having the controller23activate the electromagnetic valve24in coordination with the above step to supply the refrigerant liquid80to inside421of the inner yoke420of the first air space40so as to feed the refrigerant liquid80to the cylindrical coil100, which generates heat, via the slits423, and a step of adjusting supply amount of the refrigerant liquid80.

As another embodiment of the present invention, further, as shown inFIG. 5orFIG. 6, it may be the driving method which further comprises a step of having the controlling part20activate the circulating means82to collect the refrigerant liquid80in a gas phase800into the refrigerant liquid container81in a liquid phase80.

As another embodiment of the present invention, further, it also may be the driving method of the cureless rotating electrical machine10in which a drive shaft1000is fixed to a center part440of the cup-type mount400, and rotatably coupled to a center part240of the lid-type mount200.

As one embodiment in the third and fourth aspects of the present invention, it is preferred that the cylindrical coil100is made from what formed to a cylindrical form by either of a laminate of electrically conductive metal sheets having linear parts being spaced in an axial direction covered with insulating layers, or a linear conductor covered with an insulating layer.

As another embodiment in the third and fourth aspects of the present invention, it is preferred that the refrigerant liquid80is any of water, ethanol, ammonia, liquid nitrogen, liquid helium or fluorinated liquid.

The fifth aspect of the present invention is a driving system1for operating a coreless rotating electrical machine10under a load exceeding a rating, wherein the coreless rotating electrical machine10is shown by each of the schematic diagrams ofFIGS. 1 and 2, and the driving system1is shown by each of the schematic diagrams ofFIGS. 5 and 6.

It is the driving system1for operating be coreless rotating electrical machine10under a load exceeding a rating, wherein the driving system consists of the coreless rotating electrical machine10in which an air space40including an air gap is formed by a stator2consisting of a lid-type mount200which fixes an end face101of the energizable coreless cylindrical coil100and a rotor3having a cylindrical mount300opposingly and rotatably positioned with respect to the lid-type mount200with a plurality of magnets4equipped on an inner surface310of the cylindrical mount300, and having a channel8for supplying refrigerant liquid80to the air space40, provided on the stator2; a driving device30which is activated in coordination with the rotor3to drive the coreless rotating electrical machine10; and a controlling device20which supplies the refrigerant liquid80to the air space40in coordination with a coil temperature detecting sensor21which detects a temperature of the cylindrical coil100, equipped on the stator2.

Further, in the driving system1of the present invention, the coreless rotating electrical machine10can also be equipped, on the stator2, with a refrigerant liquid container81which is in communication with the channel8, and a circulating means82which communicates between the refrigerant liquid container81and the first air space40.

As apparent from the fifth aspect of the present invention, the driving system1is characterized in that, when activating the driving part30and operating the coreless rotating electrical machine10under the load exceeding the rating, such operation is enabled by activating the controlling part20to adjust supply amount of the refrigerant liquid80so that the temperature of the cylindrical coil100does not exceed the allowable maximum temperature tMat a rated operation, in which the refrigerant liquid80is supplied to the air space40to allow the cylindrical coil100, which generates heat, to vaporize the refrigerant liquid80so as to cool itself by latent heat of vaporization of the refrigerant liquid80.

As one embodiment of the present invention, it is more preferable that, when the driving system1operates the coreless rotating electrical machine10under the load exceeding the rating, an operation of activating the controlling device20to supply the refrigerant liquid80to the air space40so that the temperature of the cylindrical coil100does not exceed the allowable maximum temperature tMat a rated operation, and an operation to stop supplying of the refrigerant liquid80to the air space40so that the temperature of the cylindrical coil100at least does not fall below the minimum temperature tNwhere the refrigerant liquid80vaporizes by the above operation are repeated so as to maintain the temperature of the cylindrical coil100in a range between the allowable maximum temperature and the minimum temperature tN.

As another embodiment of the present invention, as shown inFIG. 5, it may be the driving system1in which the controlling device20comprises a pump22for supplying the refrigerant liquid80, and a controller23for adjusting supply amount of the refrigerant liquid80with on/off command to the pump22, wherein the controller23activates the pump22in coordination with the coil temperature detecting sensor21so as to supply the refrigerant liquid80to the air space40and also to adjust supply amount of the refrigerant liquid80.

As a further embodiment of the present invention, it may be the driving system1, as shown inFIG. 6, in which the controlling device20comprises an electromagnetic valve24for supplying the refrigerant liquid80and a controller23for adjusting supply amount of the refrigerant liquid80with open/close command to the electromagnetic valve24, wherein the electromagnetic valve24is activated in coordination with the coil temperature detecting sensor21to supply the refrigerant liquid80to the air space40from the refrigerant liquid container81arranged at a position higher than the cylindrical coil100, and also to adjust supply amount of the refrigerant liquid80.

As another embodiment of the present invention, further, as shown inFIG. 5orFIG. 6, it may be the driving system1in which the controlling device20activates the circulating means82to collect the refrigerant liquid80in a gas phase800into the refrigerant liquid container81in a liquid phase80.

As another embodiment of the present invention, further, it also may be the driving system1consisting of the coreless rotating electrical machine10in which a drive shaft1000is equipped as being fixed to a center part340of the cylindrical mount300, and rotatably coupled to a center part240of the lid-type mount200.

The sixth aspect of the present invention is a driving system1for operating a coreless rotating electrical machine10under a load exceeding a rating, wherein the coreless rotating electrical machine10is shown by each of the schematic diagrams ofFIGS. 3 and 4, and the driving system1is shown by each of the schematic diagrams ofFIGS. 5 and 6.

It forms an air space40including an air gap by a stator2consisting of a lid-type mount200which fixes one of end faces101of an energizable coreless cylindrical coil100, and a rotor3consisting of a cup-type mount400opposingly and rotatably positioned with respect to the lid-type mount200, wherein the cup-type mount400included in the rotor3has a bottom part410open at one end and closed at the other end, to which concentric inner yoke420and outer yoke430are integrated, the rotor is equipped with a plurality of magnets4with intervals41with respect to each other in a circumferential direction of an outer surface422of the inner yoke420and/or an inner surface431of the outer yoke430, and provided with slits423, each of which passing through the inner yoke420, at positions of the inner yoke420corresponding to each of the intervals41.

Further, it is the driving system1for operating the coreless rotating electrical machine10under a load exceeding a rating, wherein the driving system1consists of: the coreless rotating electrical machine10, in which the cylindrical coil100is arranged in a first air space40as suspended such that the other end face102of the cylindrical coil100leaves a clearance411between the bottom410of the cup-type mount400, a second air space50is formed between one of end faces401of the cup-type mount400and the lid-type mount200at an inner periphery side110of the cylindrical coil100, a third air space60is formed at an outer periphery side120of the cylindrical coil100, and a channel8for supplying a refrigerant liquid80to the first air space40is provided on the stator2; a driving device30which is activated in coordination with the rotor3to drive the coreless rotating electrical machine10; and a controlling part20which is activated in coordination with a coil temperature detecting sensor21equipped on the stator2to supply a refrigerant liquid80to an air space40.

Further, in the driving system1of the present invention, the cureless rotating electrical machine10can also be equipped, on the stator2, with a refrigerant liquid container81which is in communication with the channel8, and a circulating means82which communicates between the refrigerant liquid container81and the first air space40.

As apparent from the sixth aspect of the present invention, the driving system1is characterized in that, when activating the driving part30and operating the cureless rotating electrical machine10under the load exceeding the rating, such operation is enabled by activating the controlling part20to adjust supply amount of the refrigerant liquid80so that the temperature of the cylindrical coil100does not exceed the allowable maximum temperature tMat a rated operation, in which the refrigerant liquid80is supplied to inside421of the inner yoke420of the first air space40to allow the cylindrical coil100, which generates heat, to vaporize the refrigerant liquid80fed to the cylindrical coil100via the slits423so as to cool itself by latent heat of vaporization of the refrigerant liquid80.

As one embodiment of the present invention, it is more preferable that, when the driving system1operates the coreless rotating electrical machine10under the load exceeding the rating, an operation of activating the controlling device20to supply the refrigerant liquid80to inside421of the inner yoke420of the first air space40so that the temperature of the cylindrical coil100does not exceed the allowable maximum temperature tMat a rated operation, and an operation to stop supplying of the refrigerant liquid80to the first air space40so that the temperature of the cylindrical coil100at least does not fall below the minimum temperature tNwhere the refrigerant liquid80vaporizes by the above operation, are repeated so as to maintain the temperature of the cylindrical coil100in a range between the allowable maximum temperature tMand the minimum temperature tN.

As another embodiment of the present invention, as shown inFIG. 5, it may be the driving system1in which the controlling device20comprises a pump22for supplying the refrigerant liquid80to inside421of the inner yoke420of the first air space40, and a controller23for adjusting supply amount of the refrigerant liquid80with on/off command to the pump22, wherein the controller23activates the pump22in coordination with the coil temperature detecting sensor21and supplies the refrigerant liquid80to inside421of the inner yoke420of the first air space40so as to feed the refrigerant liquid80to the cylindrical coil100, which generates heat, via the slits423and also to adjust supply amount of the refrigerant liquid80.

As a further embodiment of the present invention, it may be the driving system1, as shown inFIG. 6, in which the controlling part20comprises an electromagnetic valve24for supplying the refrigerant liquid80to inside421of the inner yoke420of the first air space40and a controller23for adjusting supply amount of the refrigerant liquid80with open/close command to the electromagnetic valve24, wherein the controller23activates the electromagnetic valve24in coordination with the coil temperature detecting sensor21, and the refrigerant liquid80is supplied to inside421of the inner yoke420of the first air space40from the refrigerant liquid container81arranged at a position higher than the cylindrical coil100so as to feed the refrigerant liquid80to the cylindrical coil100, which generates heat, via the slits423and also to adjust supply amount of the refrigerant liquid80.

As another embodiment of the present invention, further, as shown inFIG. 5orFIG. 6, it may be the driving system1in which the controlling part20activates the circulating means82to collect the refrigerant liquid80in a gas phase800into the refrigerant liquid container81in a liquid phase80.

As another embodiment of the present invention, it also may be the driving system1consisting of the coreless rotating electrical machine10in which a drive shaft1000is equipped as being fixed to a center part440of the cup-type mount400, and rotatably coupled to a center part240of the lid-type mount200.

In the driving system1of the present invention, it is preferred that the cylindrical coil100of the coreless rotational electrical machine10is made from what formed to a cylindrical form by either of a laminate of an electrically conductive metal sheet having linear parts being spaced in a longitudinal direction covered with insulating layers, or a linear conductor covered with an insulating layer.

In the driving system1of the present invention, it is preferred that the refrigerant liquid80is any of water, ethanol, ammonia, liquid nitrogen, liquid helium or fluorinated liquid.

