JP2005160274A - Power device and refrigerating machine employing it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power device provided with a barrier at a position not damaging the motor characteristics and having high efficiency high torque motor characteristics. <P>SOLUTION: The power device 10 comprises a rotary shaft 31 provided with a rotary magnet 41 and an outside coupling magnet 25 while spacing apart in the axial direction, an armature coil 34, a hermetically sealed casing 13 partially provided with a bearing part 21 and a tubular thick barrier 19, and an output shaft 30 supported at the bearing part 21 of the casing 13 and provided with an inside coupling magnet 27 wherein the rotary magnet 41 and the armature coil 34 are arranged oppositely and rotatably, and the outside coupling magnet 25 and the inside coupling magnet 27 are arranged oppositely through the barrier 19. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention provides a brushless equipped with a magnet coupling mechanism configured to separate an output rotary shaft into a sealed state by a partition wall as a power source for application to industrial equipment that requires a sealed compartment configuration. The present invention relates to a power device including a DC motor and a refrigerator using the power device.

High-performance cryogenic refrigerators are used to maintain superconducting magnets, various analyzers, various measurement substrates and the like at cryogenic temperatures. In this cryogenic refrigerator, when trying to reduce the defective rate to the limit, the area around the movable part tends to be emphasized.
For example,
(1) Contamination (impurities) such as moisture and impurity gases such as carbon dioxide mixed during manufacturing and assembly or generated from working gas and components during continuous operation may not be completely removed. . For this reason, contamination in the refrigeration apparatus main body accumulates and solidifies when passing through the regenerator material made of a metal mesh member or the like, causing clogging of the metal mesh member or the like. As a result, pressure loss occurs when the working gas passes through the regenerator material, the expansion work in the expansion space is reduced, the heat exchange efficiency in the regenerator material is reduced, and the refrigeration characteristics are greatly reduced. Become.
(2) When a motor is used as a drive source, the crankcase including the motor is sealed to prevent leakage of cooling gas. However, since the coil winding etc. which consist of various materials other than a metal material are used for the motor, this coil winding etc. generate | occur | produces contamination mainly.

  In order to suppress the adverse effects caused by these contaminations, a cup-shaped partition is provided in the motor to isolate the space between the coil winding and the rotor in a gas-tight manner, and the partition and the crankcase are connected together so as to communicate with each other. Prior arts (see, for example, Patent Document 1) have already been proposed.

  The Stirling refrigerator described in Patent Document 1 has a crankshaft, an eccentric cam that drives a connecting rod, a crankcase, and a nonmagnetic cup-shaped cover that is locked to the crankcase. It houses the rotor (rotor) of the motor connected to the shaft. The armature (stator) and position sensor assembly of the brushless motor are coaxially arranged on the nonmagnetic cup-shaped cover and the rotor. The cylinder is arranged to protrude from the head.

In this prior art, in such a Stirling refrigerator, the arrangement configuration in which the stator assembly made of the armature is disposed outside the gas atmosphere prevents gas contamination and prolongs the life of the cooler. Is described.
US Pat. No. 4,769,997

The first drawback of this prior art is that a nonmagnetic cup-shaped cover is provided as a compartment for sealing the gas chamber from the atmosphere between the stator of the brushless DC motor and the rotor made of permanent magnets. . The brushless DC motor incorporating this partition wall constitutes a power unit.
The magnetic gap between the armature and the rotor is increased by the thickness of the cup-shaped cover, and the effective interlinkage magnetic flux of the armature coil interlinking with the rotor is reduced. Furthermore, if the material of the cup-shaped cover is non-magnetic but metal, etc., it increases the iron loss due to its conductivity, resulting in lowering the output torque and increasing the current of the armature coil, thereby improving efficiency. Inconvenience that deteriorates occurs.

  Further, as a second drawback, if the number of turns of the armature coil is increased in order to increase the output torque, the volume of the throttle is fixed, so that a thin wire has to be used, which increases the resistance. In addition, there is a problem that the efficiency deteriorates, and at the same time, there is a problem that the process of housing in the coil slot and the work of the coil end are complicated.

  As a third drawback, if the partition wall made of the cup-shaped cover is made thin in order to increase the effective flux linkage, the pressure strength deteriorates against the high-pressure working gas. The inner diameter of the partition must be reduced, and if the inner diameter of the partition is reduced, the magnet rotor diameter also decreases, and when the magnet rotor diameter decreases, the effective linkage flux decreases and the output torque decreases. Occur.

  Further, as a fourth drawback, since a magnet rotor is provided so as to penetrate the short armature coil, a silicon steel plate is used as a magnetic body in order to effectively close the magnetic flux of the short armature coil. Therefore, the iron loss increases, the efficiency at high speed deteriorates, and the application is limited.

  Further, as a fifth drawback, the iron loss in the partition that is non-magnetic and conductive is the effective volume of the partition where magnetic flux crosses, that is, the radial thickness of the partition, the axial length, and the cup-shaped cylindrical portion. This relates to the inner diameter, the number of flux linkages, the rate of change over time (number of rotations of the motor), and the like. For this reason, when the motor output is increased, that is, when the rotational speed is increased and the torque is increased, a contradictory problem of increasing the iron loss occurs.

  An object of the present invention is to provide a power unit using a motor having a high-efficiency and high-torque motor characteristic while providing a partition wall at a position where the motor characteristic is not impaired in view of the above-mentioned drawbacks.

  Another object of the present invention is to provide a refrigerator in which the above power unit is applied so as not to be affected by contamination.

  In order to achieve the above-described object, the present invention provides a power unit that includes a brushless DC motor and a magnetic coupling mechanism, and is rotationally driven while the motor drive unit and the output extraction unit are separated into a sealed state by the magnet coupling mechanism. Configure to transmit force. As a result, the structure and various characteristics of the motor can be designed arbitrarily while maintaining the sealed state, and the various characteristics of the motor are improved over those of the conventional example. Moreover, the structure of the motor combined with a magnet coupling mechanism can be designed arbitrarily. For example, the three types of motor configurations of the first to third embodiments can be selected and employed.

Since the refrigerator of the present invention uses the power device having the above characteristics as a power source, the cooling efficiency can be improved, and the efficiency of the device is improved by being used in various application devices.
In particular,
(1) The power unit includes a rotating shaft in which a rotor magnet and an outer coupling magnet are separated from each other in the axial direction, an armature coil, a bearing portion, and a cylindrical partition wall portion having a thin wall thickness. A casing having a sealed structure and an output shaft that is pivotally supported by a bearing portion of the casing and provided with an inner coupling magnet, the rotor magnet and the armature coil are rotatably arranged to face each other, and the outer cup A power device, wherein a ring magnet and the inner coupling magnet are arranged to face each other via the partition wall.
(2) The power unit according to (1), wherein a cylindrical reinforcing collar is provided in close contact with the cylindrical partition wall.
(3) In the power plant according to (2), the casing is formed of a non-magnetic material, and the reinforcing collar is formed of a reinforced resin.
(4) In the power unit according to any one of (1) to (3), the outer coupling magnet is provided on the rotating shaft and is connected to a substantially cylindrical portion that is provided outside the armature coil. An outer cylindrical shaft portion is provided in the length direction of the rotation shaft.
(5) In the power unit according to any one of (1) to (3), the rotor magnet is composed of two plate-shaped annular magnets, and both the annular magnets extend in the length direction of the rotating shaft. The armature coil is provided between the two annular magnets so that the plate-like surface is perpendicular to the rotating shaft at a predetermined distance.
(6) A compression chamber composed of a cylinder and a piston, an expansion chamber composed of a displacer equipped with a cylinder and a regenerator, a pipe connecting the two chambers so that the working fluid can move, and a rotation-straight line that drives the piston In a Stirling refrigerator including a conversion mechanism and a power device that transmits a rotational output to the rotation-linear conversion mechanism, the power device is the power device according to any one of (1) to (5), and The casing is configured to contain a piston and house the rotation-linear conversion mechanism and the casing of the power unit so that the working fluid in the casing is not leaked.

The effects of the present invention are as follows.
(1) Since the rotor and stator are separated by the cup-shaped cover serving as a partition wall for sealing in the conventional Stirling refrigerator motor, the structure of the motor is restricted due to the cup-shaped cover, and the rotor Since the distance of the stator is increased by the cup-shaped cover, various characteristics of the motor such as torque characteristics are deteriorated.

On the other hand, the brushless DC motor that constitutes the power unit of the present invention is separated into a magnetic coupling mechanism that similarly constitutes the power unit and two parts in structure, and the sealing structure is provided in the magnet coupling mechanism. Therefore, a brushless DC motor having an arbitrary structure can be designed and used for one magnet coupling mechanism, and the motor characteristics can be improved and an arbitrary configuration can be adopted.
In addition, since the space that includes the output shaft and is filled with the working gas (refrigerant) and the space that is formed by the motor of the power source are separated by a magnet coupling mechanism that serves as a sealed partition wall, There is no need to provide a non-magnetic cup-shaped cover as a compartment for sealing the refrigerant gas chamber from the atmosphere between the rotors, and the magnetic flux generated by the winding is effectively used by reducing the distance between the stator and the rotor. Will be able to.
(2) Since a magnetic coupling mechanism is used for the driving force transmission mechanism, an appropriate slip can be generated between the motor rotation shaft and the output shaft. For example, when the motor is started, the motor rotation shaft and the magnet cup A slip can be generated between the output shafts of the ring mechanism, so that it can be started easily.Also, during steady operation of the motor, the slip can be hardly transmitted and the rotational force can be transmitted, so the rotation control becomes easy. The motor can be driven appropriately without applying an excessive force to the motor.
(3) Since the motor is a brushless DC motor, it has high durability, low noise, good controllability, and can reduce the number of components that generate contamination such as brushes. Therefore, it is possible to perform low speed / high torque control with less noise and improved cooling characteristics.
(4) Since the refrigerator of the present invention uses the power device having the above characteristics as a power source, the cooling efficiency can be improved and the efficiency of the device can be improved by being used in various application devices. .

The brushless DC motor used in the power unit of the present invention has high durability, low noise, good controllability, fewer parts such as brushes that generate contamination, and has torque-current characteristics and rotational speed-current characteristics. Control is good because it is linear.
In addition, it does not use an inverter that generates high-frequency noise like an AC motor, and can perform rotation speed control and torque control by voltage control, so low speed and high torque control that reduces noise and improves cooling characteristics Will be able to do.
For example, the characteristics of low speed and high torque can be achieved by connecting all the armature windings in series.

  In addition, when the magnet coupling mechanism separated by the casing having the partition wall is disposed outside the motor, the interval between the stator and the rotor is reduced by the thickness of the partition wall compared to the related art in which the partition wall is in the motor. The leakage of driving magnetic flux generated by the armature winding is reduced, and the characteristics of the motor are improved. Moreover, since the magnetic coupling mechanism is a telescopic type, the storage space can be reduced.

  A refrigerator using such a power unit further improves the characteristics of the refrigerator while having the characteristics of the power unit. For example, the generated heat is reduced by lowering the rotation speed of the motor, and the generated noise is reduced.

  By applying a power unit consisting of a magnet coupling mechanism and a brushless DC motor separated by a casing having a partition wall in the refrigerator, contamination of the working gas is prevented while ensuring working gas isolation. Will be able to.

  Further, by applying the refrigerator to various application devices, contamination of the working gas space can be prevented while ensuring the isolation of the working gas.

  Other actions and effects will be described in the description of the embodiments.

  FIG. 1 is a partial cross-sectional view showing a first embodiment of a power unit using the brushless DC motor of the present invention.

The power unit 10 in FIG. 1 is roughly composed of a brushless direct current (DC) motor 9 and a magnet coupling mechanism 15.
The brushless DC motor 9 includes a rotor 11, a stator 12, a casing 13 that constitutes a casing, and a cover 14.

  The casing 13 constitutes a part of the casing of the brushless DC motor 9 and also constitutes a part of the casing in the magnet coupling mechanism 15.

  The casing 13 includes a flange portion 16, an outer cylindrical portion 17, an outer annular plate portion 18, a partition wall portion 19, an inner annular plate portion 20, a U-shaped bearing portion 21, and a shaft portion 22 from the peripheral portion toward the center. Composed.

  The casing 13 can be basically used as long as it is a non-magnetic metal. Nonmagnetic stainless steel, which contains the main component and at least one of Mn, Mo, N, and Al, is preferable. Of these, stainless steel SUS310 is a durable material with excellent corrosion resistance and durability in order to maintain the strength of the thinned partition wall, and even when processed, the relative permeability hardly changes from 1, causing magnetization. It is preferable because it exhibits a high coefficient of thermal expansion without being used, and titanium can also be used.

  The flange portion 16 is combined with a flange portion 23 of the cover 14 which will be described later to constitute a screwing portion for fixing both of them, and for fixing the casing 13 and the cover 14 to a housing (not shown). It becomes a mounting part.

  The outer cylindrical portion 17 is formed in correspondence with the cylindrical portion 24 of the cover 14, and together with the outer annular plate portion 18 and the partition wall portion 19 connected to the outer cylindrical portion 17, a movement space for the outer coupling magnet 25. Configure.

  The outer annular plate portion 18 is formed as an annular flat plate facing the bottom portion 26 of the cover 14.

  The partition wall portion 19 is formed in a thin cylindrical shape and is integrally supported at both ends in the axial direction by an outer annular plate portion 18 and an inner annular plate portion 20 that extend in a direction perpendicular to the cylindrical surface.

  When pressure is applied to the casing 13, the whole body is regarded as a cylindrical body, and the “inner annular plate portion 20 and the U-shaped bearing portion 21” corresponding to the partition portion 19 corresponding to the cylindrical portion and the substantially circular lid portion. In addition, the “outer annular plate portion 18” is different in how stress (tensile strength) is applied. That is, it is known that a larger stress (tensile strength) is applied to the lid portion than the cylindrical portion. From this, the thickness of the partition wall portion 19 corresponding to the cylindrical portion (the radial thickness when the output shaft is the center) can be formed thinner than the lid portion.

  As a result, the inner coupling magnet 27 and the outer coupling magnet 25 provided on both sides of the partition wall portion 19 can be arranged close to each other, the coupling of the coupling mechanism 15 by the magnet becomes strong, and the load is increased. Even so, the magnet on the output shaft side of the coupling mechanism 15 can rotate following the magnet on the motor side without slipping or delaying. Furthermore, the efficiency of the refrigerator is improved.

  A reinforcing collar 28 is adhered to the outer side of the partition wall portion 19 in the radial direction.

  The reinforcing collar 28 is made of a material that is non-magnetic and non-conductive, light and strong, and has excellent corrosion resistance and durability, such as FRP (fiber reinforced plastic). As the plastic, nylon, polyester, epoxy, or the like is used. As the reinforcing fiber, fibers such as boron, silicon carbide, alumina, carbon, aramid, and steel are used in addition to glass.

  The reinforcing collar is formed as a cylindrical body having a predetermined thickness (the thickness in the radial direction when the output shaft is the center is constant).

  The reinforcing collar 28 functions to reinforce the tensile strength of the partition wall portion 19.

  In the case of the above-mentioned stainless steel, the partition wall 19 is designed within a thickness range of 0.2 mm to 1 mm in terms of pressure resistance. Within this thickness range, a thickness of 0.25 to 0.3 mm is optimal.

  Of the casing 13, particularly the partition wall portion 19 that transmits magnetic flux cannot completely eliminate eddy current loss, so that the magnetic flux formed by the inner coupling magnet 27 and the outer coupling magnet 25 transmits the partition wall portion 19. In response to this, heat is generated by eddy currents. However, since the thick outer annular plate portion 18 and inner annular plate portion 20 in the casing 13 are formed continuously with the partition wall portion 19, the heat generated in the partition wall portion 19 passes outside through the following two paths. Released. The first path is a path of the partition wall portion 19-outer annular plate portion 18-outer cylindrical portion 17-flange portion 16-housing (not shown), and the second path is the partition wall portion 19-inner annular plate portion 20-. This is a path of the U-shaped bearing portion 21 -the bearing 29 -the output shaft 30.

  Furthermore, when the casing 13 is disposed at a low ambient temperature, for example, in contact with the refrigerant of the refrigerator, a considerable portion of the heat generated in the partition wall portion 19 is directly released into the refrigerant.

  The inner annular plate portion 20 is provided to secure an arrangement space for the inner coupling magnet 27.

  The U-shaped bearing portion 21 is formed in an upward U-shape so as to accommodate the bearing 29 for the output shaft 30.

  A space for accommodating the output shaft 30 including the inner coupling magnet 27 is formed by the partition wall portion 19 including the reinforcing collar 28, the inner annular plate portion 20, and the U-shaped bearing portion 21.

  The shaft portion 22 is formed in a cylindrical shape, and rotatably supports the bearing portion 32 of the rotating shaft 31 via a bearing 33.

  The cover 14 constitutes the remaining part of the brushless DC motor excluding the casing 13.

  The cover 14 includes a flange portion 23, a cylindrical portion 24, and a bottom portion 26 from the periphery toward the center.

  The flange portion 23 is combined with the flange portion 16 of the casing 13 to constitute a motor housing, and is configured as an attachment portion to a housing (not shown) that houses these.

  The cylindrical portion 24 and the bottom portion 26 form a cup shape and house the motor components.

  An iron core 35 having an armature coil 34 is attached to the cylindrical portion 24.

  The bottom portion 26 is configured by providing an upward U-shaped bearing portion 36 on a disk that serves as a lid of the cylindrical portion 24. A shaft end portion 38 of the rotary shaft 31 is rotatably supported on the U-shaped bearing portion 36 via a bearing 37. A stepped portion 39 is formed in an annular shape outside the U-shaped bearing portion 36. An annular printed board 40 is mounted on the stepped portion 39 at a predetermined distance from the end face of the armature coil 34. The printed circuit board 40 is provided with a rotation sensor 168 in the vicinity of the rotor magnet 41. The rotation sensor 168 includes, for example, a Hall IC (integrated circuit) and detects the position of the field magnetic pole.

  The magnet coupling mechanism 15 includes an outer coupling magnet 25 and an inner coupling magnet 27 having an output shaft 30. The output shaft 30 is provided with an annular inner coupling magnet 27 via an annular output shaft yoke. The magnet coupling mechanism 15 transmits the rotational force to the output shaft 30 serving as the driven shaft by the attractive force of the magnet using the rotational shaft 31 of the motor as the driving shaft. Both coupling magnets 25 and 27 are formed in an annular shape so that S and N poles appear alternately on the side surfaces. Since the magnet coupling mechanism 15 is used, it is possible to prevent misalignment such as when mechanically connecting directly.

  The rotor 11 mainly includes a rotating shaft 31 and a rotor magnet 41.

  The rotating shaft basically includes a shaft end portion, a rotor magnet support portion, a bearing shaft portion, and an outer coupling magnet support portion, and is made of metal, preferably made of a nonmagnetic material.

  In the case of the first embodiment, the rotating shaft 31 is specifically, in order from one end, the shaft end portion 38, the rotor magnet support portion 42 serving as the central shaft portion, the bearing portion 32, and the annular plate serving as the outer coupling magnet support portion. It consists of a part 43 and a cylindrical part 44.

  The rotor magnet support portion 42 includes a disc portion 45 that continues to the shaft end portion 38 and a cylindrical portion 46 that supports the rotor magnet 41.

  The bearing portion 32 is connected to the end portion of the cylindrical portion 46. Since the cylindrical part 46 is formed in a hollow cylindrical shape, it can be made lighter than a solid structure. A bearing 33 is accommodated in the bearing portion 32.

  A cylindrical portion 44 is connected to the tip of the bearing portion 32 via an annular plate portion 43.

The bearing portion 32 and the annular plate portion 43 are adapted to the space between the armature coil 34 and the partition wall portion 19 provided with the reinforcing collar 28 of the casing 13, the inner annular plate portion 20, and the U-shaped bearing portion 21. It is formed in the shape to do.
Since the rotor magnet 41 is arranged outside the cylindrical portion 46 in this space, the iron core 35 and the armature coil 34 are formed so as to be shifted outward by the width of the rotor magnet 41.

Since the bearing portion 32 can have a shape corresponding to the U-shaped bearing portion 21 of the casing 13, space can be saved.
Further, the combination of the output shaft 30 and the U-shaped bearing portion 21 can save space because the combination of the shaft portion 22 and the bearing portion 21 of the casing 13 is housed in a nested manner.

  The cylindrical portion 44 has a stepped portion 47 formed therein. The outer coupling magnet 25 is fitted and positioned on the stepped portion 47.

  For the rotor magnet 41, a magnetic material having a large holding force such as a rare earth magnet such as neodymium-iron-boron (NdFeB) is used.

  The rotor magnet 41 is set to an angle determined by the relationship between the included angle of each magnetic pole and the included angles of a plurality of coils in an armature coil 34 to be described later.

  The plurality of magnetic poles continuous in the circumferential direction of the rotor magnet 41 are magnetized in the radial direction, for example, so as to have the same polarity in the rotation direction (circumferential direction).

  The rotor magnet 41 is fixed to the outer surface of the rotor magnet support portion 42 that becomes the central shaft portion of the rotating shaft 31. Since the rotor magnet support part 42 is formed long in the length direction of the rotating shaft 31, the area on which the magnetic flux acts can be formed large.

  The stator 12 includes an armature coil 34 and an iron core 35.

  The armature coil 34 is wound in a short shape, and is shaped like a saddle by making the included angle of the conductor portion effective for torque larger than the included angle of the magnetic poles of the rotor magnet 41 by the design.

  The iron core 35 is formed as a laminated structure of magnetic plates such as silicon steel plates and is wound around the armature coil 34. The wound iron core 35 and armature coil 34 are impregnated and solidified with an insulating heat-resistant resin.

  The iron core 35 is fixed to the cylindrical portion of the cover 14.

  The space between the iron core 35 and the rotor magnet 41 is a space (gap) where the two are not in contact with each other, the magnetic resistance is the smallest, and the rotation of the rotor magnet 41 is not hindered.

  As a result, there is no provision of a cup-shaped cover as a partition wall for sealing between the stator 12 and the rotor 11 as in the conventional example, so that the motor efficiency is high without reducing the effective interlinkage magnetic flux. To be able to maintain.

  By controlling the voltage applied to the armature coil 34, the rotating magnetic field is controlled, the rotating force is applied to the rotor magnet 41, and the rotation of the rotating shaft 31 is controlled.

  For this reason, an armature voltage control device that detects the position of the field magnetic pole of the rotor magnet 41 with the rotation sensor 168 and controls the voltage applied to the armature coil 34 is provided.

The voltage amplitude at the motor is proportional to the rotor speed. Thus, the motor speed is controlled by controlling the voltage amplitude of the signal applied to the armature coil that is the stator winding.
(Effect of Example 1)
(1) Since the casing 13 for sealing is arranged as a partition between the coupling magnets 25 and 27 in the magnet coupling mechanism 15, it is sealed between the stator and the rotor of the motor as in the prior art. The cup-shaped cover as a partition wall is not provided, and the motor efficiency can be maintained at a high level without reducing the effective interlinkage magnetic flux of the coil.
(2) Since the reinforcing collar 28 is provided on the partition wall 19, the tensile strength of the partition wall 19 can be reinforced.
(3) Since the partition wall portion 19 is formed in a cylindrical shape, the thickness can be reduced as described above, and the eddy current loss in the partition wall portion 19 can be reduced.
(4) Since the cylindrical part 46 of the rotating shaft 31 is formed in a hollow cylindrical shape, it can be made lighter than a solid structure.
(5) Since the bearing portion 32 of the rotating shaft 31 can have a shape corresponding to the U-shaped bearing portion 21 of the casing 13, space can be saved.
(6) Since the combination of the shaft portion 22 and the bearing portion 32 of the casing 13 accommodates the combination of the output shaft 30 and the U-shaped bearing portion 21 in a nested manner, the space can be saved.
(7) A space for accommodating the output shaft 30 provided with the inner coupling magnet 27 can be formed by the partition wall portion 19 provided with the reinforcing collar 28, the inner annular plate portion 20, and the U-shaped bearing portion 21.
(8) The outer cylindrical portion 17 of the casing 13 can constitute a moving space of the outer coupling magnet 25 together with the outer annular plate portion 18 and the partition wall portion 19 that are continuously provided.

FIG. 2 is a partial cross-sectional view showing a second embodiment of a power unit using the brushless DC motor of the present invention.
The second embodiment is different from the first embodiment in the following points, and the remaining configuration is not different from the configuration of the first embodiment. For the structure which is not different, the description of FIG. 1 is used and the description is omitted here.
(1) The rotor magnet support portion 42 serving as the central shaft portion of the rotating shaft 31 has a hollow shaft structure in the first embodiment, but a solid structure in the second embodiment.
(2) The rotating shaft 31 of the second embodiment adopts a configuration that is not in the first embodiment, that is, the length direction of the rotating shaft 31 that is connected to the cylindrical portion 44 that supports the outer coupling magnet 25. The outer cylindrical shaft portion 48 is provided, and the armature coil block 49 is disposed between the rotor magnet 41 and the outer cylindrical shaft portion 48.

Specifically, the above point (1) adopts a configuration in which the central portion of the rotating shaft 31 is a solid structure. Thereby, the mechanical strength of a rotating shaft can be raised and the outer cylindrical shaft part 48 can be supported.
The point (2) is configured as follows. An outer cylindrical shaft portion 48 is provided in the lengthwise direction of the rotation shaft 31 in a continuous manner with the cylindrical portion 44 that supports the outer coupling magnet 25 of the rotation shaft 31. The lengthwise end of the outer cylindrical shaft portion 48 extends to the vicinity of the shaft end portion of the rotating shaft 31. The thickness of the outer cylindrical shaft portion 48 in the radial direction is made thinner than the radial thickness of the cylindrical portion 44 that supports the outer coupling magnet 25.

  By providing the outer cylindrical shaft portion 48 on the rotary shaft 31, the inertial mass of the rotary shaft 31 can be increased and the flywheel can be operated. Further, by connecting the cylindrical portion 44 that supports the outer coupling magnet 25 and the outer cylindrical shaft portion 48, the misalignment at the time of transmitting force acting on the cylindrical portion 44 that supports the outer coupling magnet 25 is suppressed. can do.

  An armature coil block 49 is disposed in a space formed between the outer cylindrical shaft portion 48 and the rotor magnet 41.

  The armature coil block 49 molds the armature coil 34 excluding the iron core 35 and the rotation sensor 168 in the first embodiment into a substantially cylindrical shape with a sealing resin. The rotation sensor 168 is disposed near the lower end of the rotor magnet 41. The armature coil block 49 is attached to the bottom portion 26 of the cover 14.

  Since the armature coil block 49 does not include the iron core 35 as in the first embodiment, the armature coil block 49 can be disposed close to the rotor magnet 41. Thereby, magnetic resistance can be made small and generated magnetic flux can be made to act on rotor magnet 41 effectively.

It is also possible to provide a magnetic body for short-circuiting the magnetic flux generated in the armature coil 34 on the outer cylindrical shaft portion 48.
(Effect of Example 2)
About the same structure as Example 1, since there exists the same effect, description is abbreviate | omitted.

  By adopting a configuration in which the central portion of the rotating shaft 31 has a solid structure, the mechanical strength of the rotating shaft can be increased.

  By providing the outer cylindrical shaft portion 48 on the rotary shaft 31, the inertial mass of the rotary shaft 31 can be increased and the flywheel can be operated. Further, by connecting the cylindrical portion 44 that supports the outer coupling magnet 25 and the outer cylindrical shaft portion 48, the misalignment at the time of transmitting force acting on the cylindrical portion 44 that supports the outer coupling magnet 25 is suppressed. can do.

  FIG. 3 is a partial cross-sectional view showing a third embodiment of the power transmission device using the brushless DC motor of the present invention.

The third embodiment is different from the first embodiment in the following points, and the remaining configuration is not different from the configuration of the first embodiment. For the structure which is not different, the description of FIG. 1 is used and the description is omitted here.
(1) The configuration of the brushless DC motor is a disk type.
As shown in FIG. 3, a disk rotation type mechanism in which a thin armature coil 51 is sandwiched so that an upper rotor magnet 52 and a lower rotor magnet 53 that are annular plates are arranged to rotate in a plane perpendicular to the axial direction of the rotation axis. Is adopted.

  A thin armature coil 51 and a rotation sensor 168 constitute an armature coil block 50.

  The rotor 11 includes a rotating shaft 31 and a rotor magnet 41. The rotating shaft 31 includes a first shaft portion 54 and a second shaft portion 55. The first shaft portion 54 includes a central shaft portion 56, a bearing portion 32, an annular plate portion 43, and a cylindrical portion 44 that are integrally formed from one end to the other end. The second shaft portion 55 includes a shaft end portion 57 at one end of a hollow cylindrical shaft, and an annular plate portion 58 that extends outward in the axial direction. The central shaft portion 56 of the first shaft portion 54 is fitted and fixed in the cylindrical shaft of the second shaft portion 55 to integrate them.

  In the integrated rotating shaft 31, the outer coupling magnet 25 is fixed to the stepped portion 47 inside the cylindrical portion 44 of the first shaft portion 54, and the upper rotor magnet 52 of the annular flat plate is formed on the lower surface side of the annular plate portion 43. Is fixed to the upper surface of the annular plate portion 58 of the second shaft portion 55, and the lower rotor magnet 53 of the annular flat plate is fixed, and the shaft end portion 57 is attached to the U-shaped bearing portion 36 of the bottom portion 26 of the cover 14. Support through.

  An armature coil block 50 in which an armature coil 51 is mounted on a printed circuit board 59 and fixed with resin is inserted between the upper and lower rotor magnets 52 and 53, and the armature coil block 50 is inserted into the casing 13 via the printed circuit board base. The flange portion 16 is fixed. The printed circuit board 59 is also provided with a rotation sensor 168. The rotation sensor 168 includes a Hall IC (integrated circuit) or the like, and detects the positions of the field magnetic poles of both the rotor magnets 52 and 53.

  The upper rotor magnet 52 and the lower rotor magnet 53 are made of, for example, a magnetic material having a large coercive force, such as a rare earth magnet, and are magnetized so as to have different polarities alternately in the circumferential direction, for example. Both rotor magnets 52 and 53 are set such that the angle between the magnetic poles is determined by the relationship with the angle between the plurality of coils in the armature coil 51 described later.

  The armature coil 51 is formed of a combination of flat unit coils that are wound in a fan shape on a plane and the included angle of the coil portion effective for torque is greater than 180 degrees in electrical angle.

  The armature coil 51 is configured by arranging the unit coils radially in a plane and at equal pitches so that their outer portions are adjacent to each other, and solidifying with resin. The armature coil 51 is formed in a ring shape as a whole.

  The upper rotor magnet 52 and the lower rotor magnet 53 arranged opposite to the upper rotor magnet 52 are configured to oppose each other by a magnetic attractive force between different poles and to rotate synchronously. For example, when the facing surface of the upper rotor magnet 52 is magnetized in order to the NSN -... pole, and the facing surface of the lower rotor magnet 53 is magnetized to the SNSS ... in the reverse order. In addition, a magnetic field is generated from the upper part to the lower part and vice versa.

By controlling the voltage applied to the armature coil 51, the rotating magnetic field is controlled, a rotational force is applied to the upper rotor magnet 52 and the lower rotor magnet 53, and the rotation of the rotating shaft is controlled.
For this reason, an armature voltage control device that detects the position of the field magnetic pole of the upper rotor magnet 52 or the lower rotor magnet 53 with the rotation sensor 168 and controls the voltage applied to the armature coil 51 is provided.
(Effect of Example 3)
About the same structure as Example 1, since there exists the same effect, description is abbreviate | omitted.

  Since the rotating part of the brushless DC motor is configured in a disk shape, the height in the length direction of the rotating shaft of the motor part is shorter than the cylindrical type in the first and second embodiments, in other words, it can be configured thinner. .

  The upper rotor magnet 52 and the armature coil, which is a source of contamination, are separated and shielded by a partition wall in a sealed state, and the magnetic flux generated by the upper rotor magnet 52 is effectively used for torque generation. Since the lower rotor magnet 53 for forming the magnetic path is provided, the leakage magnetic flux between the upper rotor magnet 52 and the lower rotor magnet 53 for closing the magnetic path can be reduced, and the low speed and high speed can be reduced. Efficiency and high torque characteristics can be achieved.

  FIG. 4 is a schematic diagram of a Stirling refrigerator incorporating a power device using the brushless DC motor of the present invention as a power source and incorporating the power device. That is, FIG. 4 is a schematic view showing an embodiment in which the power unit having a partition wall according to the present invention is applied to a Stirling refrigerator requiring a partition wall. The configuration other than the brushless DC motor is schematically shown. The brushless DC motor used in this embodiment will be described using the configuration of the type of the first embodiment. The brushless DC motor can also be applied to other types of configurations.

In the Stirling refrigerator 61, a compression chamber 64 is formed between the operating end of the piston 62 and the first cylinder portion 77 of the crankcase 63, and between the operating end of the displacer 65 and the second cylinder portion 78 of the crankcase 63. An expansion chamber 66 is formed, and a cool storage material 67 is provided inside the displacer 65. The compression chamber 64 and the expansion chamber 66 are connected by a gas transfer path 68. The space for accommodating the displacer 65 of the crankcase 63 is sealed by an annular packing 79 except for the gas transfer path 68 and the shaft. The piston 62 and the displacer 65 are synchronously driven by the power unit 10 via the crankshaft 69. The casing 13 including the partition wall 19 of the magnet coupling mechanism 15 is attached to the crankcase 63 in a sealed state via a rubber packing 70 such as an O-ring provided in the concave groove.
The casing 13 provided with the rubber packing 70 is attached directly to the case wall of the crankcase 63 or to an attachment portion protruding from the case wall. Thereby, the inside of the crankcase 63 is isolated in a sealed state on the crankshaft 69 side and the motor side.

  During operation, working gas (He gas) is sealed in a sealed space formed by the compression chamber 64, the expansion chamber 66, and the gas transfer path 68, and the working gas is compressed by the piston 62 and then sent to the expansion chamber 66 to be displacer. Adiabatic expansion is performed at 65, and after expansion, the air is sent back to the compression chamber 64 and compressed again, and the same process is repeated. By repeating the above cycle, the cryogenic cold head 71 is formed at the end of the case where the expansion chamber 66 is formed.

  The crankshaft side working gas in the crankcase 63 is prevented from entering the motor-side space 72 by the crankcase 63, the rubber packing 70 such as an O-ring, and the casing 13 having the partition wall 19.

The dotted line is an apparatus other than the Stirling refrigerator, and is a measuring apparatus that collects and processes measurement data from the measuring element or the like when the measuring element or measuring apparatus is provided in the cold head 71. This type of measuring device generally includes a computer 75 and a monitor 76. Collection and processing of measurement data are executed by a computer based on application software.
(Effect of Example 4)
Since the output shaft 30 of the power unit 10 is housed in a space 73 on the crankshaft side separated by the casing 13, the output shaft 30 can be connected to the crankshaft 69 without a dynamic seal, and the motor is driven by the casing 13. Since it is disposed in the space 72 to be isolated, it is not necessary to bring the cooling means for the motor into the space on the crankshaft side.

  A crankcase 63, a rubber packing 70 such as an O-ring, and a casing 13 having a partition wall 19 divide the inside of the crankcase 63 into a sealed state, one of which is a Stirling refrigerator side mechanism including a displacer, and the other is a motor side mechanism. Since it can be stored, it is possible to prevent contamination generated by the motor from entering the Stirling refrigeration mechanism.

[Infrared camera using a small Stirling refrigerator]
As an application target of the Stirling refrigerator as shown in the fourth embodiment, there is an infrared camera because of the temperature characteristic of the cold head at a very low temperature. Photoconductive elements provided in the cold head include semiconductor crystals such as InSb (indium tin), Ge (germanium) and Si (silicon), and Ge and Si with Au (gold), Zn (zinc), and Hg (mercury). The material etc. which added heavy metals, such as, are used. The InSb is generally used at a temperature below liquid nitrogen, and the sensitivity increases as the operating temperature is lowered, but the response speed is slow. On the other hand, semiconductor crystals such as Ge and Si, and materials obtained by adding heavy metals such as Au, Zn, and Hg to Ge and Si are generally used at temperatures below liquid nitrogen, and the response speed is as fast as microseconds or less.

By mounting these photoconductive elements on a cold head and cooling them to a temperature below liquid nitrogen, the dynamic range of spectral sensitivity can be widened.
The output of the photoconductive element mounted on the cold head is taken into the computer 75 as the surface output of the element array, as shown in FIG. 4, and necessary A / D conversion, orthogonal conversion, filtering, image conversion, etc. are performed. As a result, the image can be displayed on the monitor 76 as a far-infrared image or the like. By configuring the computer 75 as a one-chip or one-board microcomputer and configuring the monitor 76 with a small-sized liquid crystal screen, a portable infrared camera can be configured.

[Gas monitor using small Stirling refrigerator]
As an application object of the Stirling refrigerator, there is a gas monitor in addition to the infrared camera of the fifth embodiment. The cold head is provided with a gas sensor and cooled to a temperature near liquid nitrogen.

  As a gas sensor, a gas to be measured is brought into contact with a reflecting mirror whose temperature can be changed from room temperature to an arbitrary temperature of −80 ° C. or less, and the condensed light beam or the laser beam is applied to a portion of the reflecting mirror in contact with the gas. Radiate and gradually reduce the temperature of the reflector before contacting the reflector and the gas or contact the reflector and the gas to form dew and / or frost on the reflector. The temperature of the reflector is gradually heated to the extent that dew and / or frost is not completely sublimated from the mirror surface near the dew point and / or near the dew point, and thus the temperature at which the intensity of scattered light is maximized, and / or The temperature at which the intensity of reflected light is minimized, or the temperature at which the intensity of scattered light is minimized and / or the temperature at which the intensity of reflected light is maximized is detected by cooling the reflector. The temperature and its minimum temperature are the dew point and the gas By determining the dew point or frost point of a gas containing a trace amount of moisture, including setting it as a frost point, the gas containing low moisture content is brought into contact with a temperature-variable reflector, and the temperature of the reflector is lowered. Some form a layer and repeat heating and cooling at temperatures in the vicinity to know the exact dew point and / or frost point of the gas from the sublimation point and the stacking freezing point.

  Thereby, the gas monitor using the Stirling refrigerator of the present invention is portable and easy to use.

[Semiconductor radiation detector using small Stirling refrigerator]
As an application target of the Stirling refrigerator, there is a semiconductor radiation detector. The cold head is provided with a semiconductor radiation detection element and cooled to a temperature in the vicinity of liquid nitrogen. The semiconductor radiation detection element is a Ge detection element or a Si detection element, for example, a closed-end Ge gamma ray detection element.

  Conventionally, since the semiconductor radiation detecting element is cooled by a cooling tank containing liquid nitrogen, it is necessary to obtain liquid nitrogen every time it is used, and the place of use is limited. When the Stirling refrigerator of the present invention is used, the semiconductor radiation detection element only needs to be provided in the cold head, and it is easy to carry and easy to use.

  Since the power unit of the present invention is as described above, contamination is completely isolated, the characteristics of the brushless DC motor can be effectively exhibited, generation of unnecessary noise to an external device can be suppressed, low speed, high torque Since it can exhibit good cooling capacity with a smaller shape for control, it can be applied to the cooling and air conditioning fields that require such characteristics.

It is a partial cross section figure which shows Example 1 of the power plant using the brushless DC motor of this invention. It is a partial cross section figure which shows Example 2 of the power plant using the brushless DC motor of this invention. It is a partial cross section figure which shows Example 3 of the power plant using the brushless DC motor of this invention. 1 is a schematic view of a Stirling refrigerator incorporating a power device using a brushless DC motor of the present invention as a power source and incorporating the power device.

Explanation of symbols

9 Brushless direct current (DC) motor 10 Power unit 11 Rotor 12 Stator 13 Casing 14 Cover 15 Magnet coupling mechanism 16, 23 Flange portion 17 Outer cylindrical portion 18 Outer annular plate portion 19 Partition portion 20 Inner annular plate portions 21, 32, 36 Bearing part 22 Shaft part 24, 44, 46, 49 Cylindrical part 25 Outer coupling magnet 26 Bottom part 27 Inner coupling magnet 28 Reinforcement collars 29, 33, 37 Bearing 30 Output shaft 31 Rotating shaft 34, 51 Armature coil 35 Iron cores 38, 57 Shaft end portions 39, 47 Stepped portion 40 Printed circuit board 41 Rotor magnet 42 Rotor magnet support portions 43, 58 Annular plate portion 45 Disc portion 48 Outer cylindrical shaft portion 50 Armature coil block 52 Upper rotor magnet 53 Lower rotor Magnet 54 1st axis 55 second shaft portion 56 central shaft portion 59 printed circuit board 61 Stirling refrigerator

Claims (6)

A casing having a hermetic configuration including a rotating shaft provided with a rotor magnet and an outer coupling magnet spaced apart in the axial direction, an armature coil, and a bearing portion and a cylindrical wall portion having a thin wall thickness in a part; The rotor shaft and the armature coil are rotatably arranged opposite to each other, and the outer coupling magnet and the inner coupling are supported by an output shaft provided with an inner coupling magnet. A power unit, wherein a magnet is disposed to face each other with the partition wall interposed therebetween. 2. The power unit according to claim 1, wherein a cylindrical reinforcing collar is provided in close contact with the cylindrical partition wall. The power unit according to claim 2, wherein the casing is made of a non-magnetic material, and the reinforcing collar is made of a reinforced resin. The outer cylindrical shaft portion is provided outside the armature coil in the lengthwise direction of the rotation shaft so as to be connected to the substantially cylindrical portion where the outer coupling magnet is provided on the rotation shaft. 4. The power unit according to any one of items 3. The rotor magnet is composed of two plate-like annular magnets, and both the annular magnets are provided so as to be separated from each other by a predetermined distance in the length direction of the rotary shaft so that the plate-like surfaces are orthogonal to the rotary shaft, The power unit according to any one of claims 1 to 3, wherein the armature coil is provided between both annular magnets. A compression chamber composed of a cylinder and a piston; an expansion chamber composed of a displacer provided with a cylinder and a regenerator; a pipe connecting the two chambers so that the working fluid can move; and a rotation-linear conversion mechanism for driving the piston; In a Stirling refrigerator comprising a power device that transmits rotational output to the rotation-linear conversion mechanism,
The power device according to any one of claims 1 to 5, wherein the working fluid in the housing is not leaked by a housing including the piston and housing the rotation-linear conversion mechanism and a casing of the power device. A Stirling refrigerator characterized by being configured as described above.

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