JP2013055752A - Permanent magnet type motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve system efficiency of a permanent magnet type motor.SOLUTION: A permanent magnet type motor includes: a rotor shaft 21 having a center hole 22 in which a refrigerant flows and a communication hole 28 communicating the center hole 22 with the outer surface thereof; a rotor core 23 fixed to the outer surface of the rotor shaft 21; a permanent magnet 25 fixed to the rotor core 23; a through hole 31 penetrating through the rotor core 23 axially; a radial hole 29 communicating the communication hole 28 with the through hole 31; and a refrigerant flow passage opening/closing mechanism 70 disposed between the communication hole 28 and the radial hole 29 to open/close the communication hole 28 and the radial hole 29. The refrigerant flow passage opening/closing mechanism 70 closes the communication hole 28 when the rotational frequency of a rotor 20 is ror less, closes the radial hole 29 when the rotational frequency of the rotor 20 is equal to or more than rwhich is larger than r, and opens both of the communication hole 28 and the radial hole 29 when the rotational frequency of the rotor 20 is over rand under r.

Description

  The present invention relates to a cooling structure for a permanent magnet motor.

  A permanent magnet motor is used in which a permanent magnet is attached to the surface or inside of a rotor core made of laminated steel plates, and the rotor is rotated by a rotating magnetic field generated by the stator and an electromagnetic force acting on the rotor core. For drive control of such a permanent magnet motor, pulse control by an inverter is often used. However, since the permanent magnet generates heat due to a ripple current caused by the pulse, a refrigerant is provided in a flow path provided in the vicinity of the permanent magnet. Is used to cool the permanent magnet.

  The refrigerant flow path penetrates the rotor core of the laminated steel sheet in the axial direction. However, when the rotation speed of the rotor increases, the rotor flows from the gap between the steel sheets in which a part of the refrigerant flowing through the refrigerant flow path is laminated due to centrifugal force. It flows out into the gap between the stator and the stator, and there is a problem that it becomes a rotational resistance of the rotor and lowers the operation efficiency of the motor. Thus, a method has been proposed in which the amount of refrigerant supplied to the refrigerant flow path in the vicinity of the permanent magnet is reduced when the rotational speed of the rotor increases (see, for example, Patent Document 1).

  Further, in the permanent magnet motor, since the heat generation of the permanent magnet is small when the rotation speed of the rotor is low, the amount of refrigerant supplied to the refrigerant flow path in the vicinity of the permanent magnet is limited, and when the rotation speed is high, the permanent magnet A method has been proposed in which a refrigerant is supplied to a refrigerant flow path in the vicinity of the rotor to reduce the agitation loss of the refrigerant by the rotor and the loss of the refrigerant pump, thereby improving the operation efficiency of the motor (for example, see Patent Document 2). .

JP 2009-290979 A JP 2009-118714 A

  By the way, when a permanent magnet motor controlled by pulse control is used as a drive source for an electric vehicle, the pulse control method varies among PWM control, overmodulation control, and rectangular wave control according to the output and the driving state of the vehicle. . For this reason, the temperature of the permanent magnet is high in the intermediate rotation speed range of the motor, and the temperature of the permanent magnet is not so high in the low rotation speed range or the high rotation speed range of the rotor. is there.

  However, in the prior art described in Patent Documents 1 and 2, the refrigerant flow rate is reduced only when the rotor rotation speed is in the high rotation area or when the rotor rotation speed is in the low rotation area. It is difficult to increase the flow rate of the refrigerant in the medium rotation speed range where the temperature of the permanent magnet becomes high and to reduce the flow rate of the refrigerant in other rotation speed ranges, including the cooling system. There was a limit to improving the system efficiency of permanent magnet motors.

  Moreover, since the prior art described in Patent Documents 1 and 2 opens and closes the refrigerant flow path by the reaction force of the elastic material that antagonizes the centrifugal force applied to the member mass, the shape and mass (weight) of the member are If it is not managed accurately, the refrigerant flow rate will vary and the refrigerant flow rate will become excessive, reducing the motor's operating efficiency, or the refrigerant flow rate will be insufficient and the temperature of the permanent magnet will increase, and the rotor torque will increase. There was a problem that the loss increased. Furthermore, it may be necessary to increase the refrigerant supply pump in consideration of the flow rate variation. In this case, there is a problem that the system efficiency of the permanent magnet motor is further reduced.

  An object of this invention is to improve the system efficiency of a permanent magnet type motor.

  A permanent magnet type motor according to the present invention includes a first refrigerant channel that extends in an axial direction and through which a refrigerant flows, and a second refrigerant channel that communicates the first refrigerant channel with an outer surface thereof. A rotor comprising a shaft, a laminated steel plate, and a rotor core fixed to the outer surface of the rotor shaft; and a permanent magnet fixed to the rotor core; and disposed in the vicinity of the permanent magnet, the rotor core in the axial direction A third refrigerant channel penetrating through, a fourth refrigerant channel provided in the rotor and communicating with the second refrigerant channel and the third refrigerant channel, the second refrigerant channel, and the fourth A refrigerant magnet opening / closing mechanism that is disposed between the refrigerant channels and opens and closes the second refrigerant channel and the fourth refrigerant channel, wherein the refrigerant channel opening / closing mechanism is provided. When the rotational speed of the rotor is less than or equal to a first predetermined value When the second refrigerant flow path is closed and the rotational speed of the rotor is equal to or greater than a second predetermined value greater than the first predetermined value, the fourth refrigerant flow path is closed and the rotation of the rotor When the number exceeds the first predetermined value and is less than the second predetermined value, both the second refrigerant channel and the fourth refrigerant channel are opened.

  In the permanent magnet type motor of the present invention, the refrigerant flow path opening / closing mechanism is configured such that the increase / decrease in the opening degree of the second refrigerant flow path is opposite to the increase / decrease in the opening degree of the fourth refrigerant flow path. It is also preferable to change the opening degree of the refrigerant flow path and the fourth refrigerant flow path.

  In the permanent magnet type motor of the present invention, the rotor shaft has a guide hole penetrating between an outer surface thereof and the first refrigerant channel, and the refrigerant channel opening / closing mechanism includes the second refrigerant channel. A first valve body portion for closing, a second valve body portion for closing the fourth refrigerant flow path, and a pressure receiving portion for receiving the refrigerant pressure of the first refrigerant flow path, and is guided in the radial direction by the guide hole. And a resilient member that urges the valve member radially toward the first refrigerant flow path.

  In the permanent magnet type motor of the present invention, when the first valve body portion of the valve member closes the second refrigerant channel, the surface receiving the refrigerant pressure of the pressure receiving unit is the surface of the first refrigerant channel. It is also preferable that the outer circumferential edge of the guide hole is recessed radially outward from the surface of the first refrigerant channel. It is also suitable as being.

  In the permanent magnet type motor of the present invention, it is preferable that the fourth refrigerant flow path is a flow path provided in the rotor core and extending in a radial direction. It is also preferable that the flow path is provided outside the rotor core and extends in the radial direction.

  The present invention has an effect of improving the system efficiency of a permanent magnet type motor.

It is sectional drawing of the permanent magnet type motor in embodiment of this invention. It is an enlarged view of the A section shown in FIG. It is sectional drawing of the axial direction of the permanent magnet type motor in embodiment of this invention. It is explanatory drawing which shows operation | movement of the refrigerant | coolant flow path opening / closing mechanism of the permanent magnet type motor in embodiment of this invention. It is explanatory drawing which shows operation | movement of the refrigerant | coolant flow path opening / closing mechanism of the permanent magnet type motor in embodiment of this invention. It is a graph which shows the permanent magnet high temperature area | region of the permanent magnet type motor in embodiment of this invention. It is a graph which shows the change of the torque loss with respect to the rotation speed of the rotor of the permanent magnet type motor in embodiment of this invention. It is explanatory drawing which shows other embodiment of the permanent magnet type motor of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. As shown in FIG. 1, the permanent magnet type motor 100 of the present embodiment is disposed on a casing 10, a stator 40 fixed to the inner surface of the casing 10, and an inner peripheral side of the stator 40, and is rotatable on the casing 10. And a supported rotor 20. The stator 40 is formed by laminating thin electromagnetic steel plates, and a stator core 41 having a plurality of slots on the inner peripheral side, and a coil wound around each slot of the stator core 41 protrudes from both end surfaces of the stator core 41 in the axial direction. The second coil ends 42 and 43 are provided. The rotor 20 includes a hollow rotor shaft 21 having a center hole 22, a thin electromagnetic steel plate 24, a rotor core 23 fixed to the outer surface 21 b of the rotor shaft 21, and a permanent magnet 25 attached in the rotor core 23. And first and second end plates 26 and 27 that sandwich the rotor core 23 and the permanent magnet 25 from both sides in the axial direction. The first and second end portions 21e and 21f of the rotor shaft 21 are connected to the rotary shaft 91 by first and second ball bearings 13 and 14 respectively attached to the first end plate 11 and the second end plate 12 of the casing 10. It is attached to the casing 10 so as to be rotatable around. The central hole 22 of the rotor shaft 21 is a first refrigerant flow path through which the refrigerant flows in the direction of the rotation shaft 91. The end plates 26 and 27 are fixed to the outer surface 21 b of the rotor shaft 21 together with the rotor core 23.

  On the rotor shaft 21 side of the first end plate 26 of the rotor 20, a protrusion 35 protruding in the axial direction toward the first end 21 e of the rotor shaft 21 is provided. A ring-shaped cavity 34 is provided. Further, a radial hole 29 that communicates with the cavity 34 and extends in the radial direction and an axial hole 30 that communicates with the radial hole 29 are provided inside the radially outer side of the protrusion 35 of the first end plate 26. I have.

  The rotor core 23 is provided with a through hole 31 penetrating the rotor core 23 along the permanent magnet 25 in the direction of the rotation shaft 91. The axial hole 30 provided in the first end plate 26 is connected to the through hole 31. It communicates with the through hole 31 at the same position in the radial direction and the circumferential direction. The second end plate 27 of the rotor 20 is provided at the same position as the through hole 31 in the radial direction and the circumferential direction, and an axial hole 32 communicating with the through hole 31 is provided. The through hole 31 is a third refrigerant channel.

  The rotor shaft 21 is provided with a communication hole 28 that communicates with a cavity 34 provided in the first end plate 26. The communication hole 28 communicates the through hole 31 that is the third refrigerant channel and the center hole 22 that is the first refrigerant channel via the cavity 34, the radial hole 29, and the axial hole 30. The radial hole 29 is a fourth refrigerant flow path that communicates with the communication hole 28 that is the second refrigerant flow path and the through hole 31 that is the third refrigerant flow path via the cavity 34 and the axial hole 30. . Further, since the radial hole 29 is provided in the first end plate 26 outside the rotor core 23, it is a fourth refrigerant flow path provided outside the rotor core 23.

  In the cavity 34 between the communication hole 28 that is the second refrigerant flow path and the radial hole 29 that is the fourth refrigerant flow path, the communication hole 28 and the radial hole 29 are opened and closed to open the refrigerant holes 28 and 29. A refrigerant flow path opening / closing mechanism 70 that opens and closes the circulation of the refrigerant is provided. As shown in FIGS. 2 and 3, the refrigerant flow path opening / closing mechanism 70 includes a valve member 71 and an elastic member 76 that urges the valve member 71 in the radial direction. The valve member 71 includes a first valve body portion 72 that fits into an end portion on the cavity 34 side of the communication hole 28 that is the second refrigerant flow path, and blocks the flow of the refrigerant in the communication hole 28, and a fourth refrigerant flow path. The second valve body portion 73 that fits into the end portion of the radial hole 29 on the cavity 34 side and blocks the flow of the refrigerant in the radial hole 29, and the guide hole 33 provided in the rotor shaft 21. The guide part 74 is provided. The first valve body part 72 and the second valve body part are round and mortar-shaped protrusions, the tips respectively enter the communication hole 28 or the radial hole 29, and the tapered surface near the root is the communication hole 28. Then, when it hits the opening end surface of the radial hole 29 on the cavity 34 side, the flow of the refrigerant in the communication hole 28 and the radial hole 29 is blocked, and the taper surface near the root is the communication hole 28 and the opening of the radial hole 29 on the cavity 34 side. When separated from the end face, the refrigerant flows through the communication hole 28 and the radial hole 29. In addition, the flow rate of the refrigerant can be increased or decreased by a gap between the tapered surface near the root and the opening end surface of the communication hole 28 and the radial hole 29 on the cavity 34 side.

  The guide hole 33 is a hole provided in the rotor shaft 21 so as to communicate between the center hole 22 and the cavity 34 in the radial direction. The peripheral edge on the center hole 22 side is the surface of the center hole 22 or a hollow shape. Spot facings 36 are provided so as to be recessed radially outward from the inner surface 21a of the rotor shaft 21. The end surface of the guide portion 74 of the valve member 71 on the side of the center hole 22 is a pressure receiving surface 75 that receives the pressure P of the refrigerant flowing into the center hole 22. The pressure receiving surface 75 is configured such that when the first valve body portion 72 is fitted into the communication hole 28, the radial position thereof becomes the region of the guide hole 33. At this time, the pressure receiving surface 75 only needs to be positioned radially outside the surface of the center hole 22 or the inner surface 21 a of the rotor shaft 21, and may not enter the region of the guide hole 33.

  As shown in FIG. 3, elastic members 76 that connect the lugs 77 provided on the outer surface of the rotor shaft 21 in the circumferential direction are attached to both end surfaces of the valve member 71 in the circumferential direction. As shown in FIG. 3, the lug 77 is provided at a position closer to the center line 92 in the horizontal direction than the first valve body portion 72 in the direction along the guide hole 33 (the direction of the center line 93). Thus, the first valve body 72 of the valve member 71 is pressed against the end surface of the communication hole 28 on the cavity 34 side by the tension of the elastic member 76. That is, the elastic member 76 urges the valve member 71 radially inward.

  The permanent magnet type motor 100 of the present embodiment is connected to a refrigerant supply pump 51 that supplies refrigerant to the coil ends 42 and 43 of the stator 40 and the center hole 22 of the rotor shaft 21 and an outlet of the refrigerant supply pump 51. Refrigerant supply pipe 52, refrigerant pipes 53 to 55 that branch from refrigerant supply pipe 52 and lead the refrigerant to coil ends 42 and 43, and refrigerant pipes 54 and 55 are connected to each other, and each coil end 42 and 43 is sprayed with refrigerant. Orifices 56 to 58 which are attached to the first and second refrigerant blowing pipes 61 and 62 and the refrigerant pipes 53 to 55 and adjust the flow rate ratio of the refrigerant supplied to the center hole 22 and the coil ends 42 and 43; It has. As shown in FIG. 1, a part of the refrigerant pressurized by the refrigerant supply pump 51 flows into the center hole 22 of the rotor shaft 21 from the refrigerant supply pipe 52, and the refrigerant flow path opening / closing mechanism 70 is opened. In this case, the permanent magnet 25 is cooled from the central hole 22 through the communication hole 28, the cavity 34, the radial hole 29, the axial hole 30, the through hole 31 of the rotor core 23, and the casing 10 through the axial hole 32. It is discharged into the inside. A part of the refrigerant pressurized by the refrigerant supply pump 51 is blown from the first refrigerant blowing pipes 61 and 62 to the first and second coil ends 42 and 43 through the refrigerant pipes 53 and 54.

The permanent magnet type motor 100 of this embodiment has a rotational speed and a maximum output characteristic as shown by a line a in FIG. As shown in FIG. 6, when the rotational speed of the rotor is equal to or less than r ₀ , the maximum output (torque) is constant at T ₀ regardless of the rotational speed, and when the rotational speed of the rotor exceeds r ₀ , the rotational speed is The maximum output (torque) gradually decreases as the value increases. When the rotational speed of the rotor exceeds r ₁ , the control method is PWM control, and the temperature of the permanent magnet 25 increases due to the ripple current in the vicinity of the maximum output whose output is close to the line a. When the rotational speed of the rotor exceeds r ₂ , the control method shifts to rectangular wave control or overmodulation control, so that the ripple current is reduced and the temperature of the permanent magnet 25 is not so high. In FIG. 6, a hatched region c surrounded by a dotted line b is a region where the temperature of the permanent magnet 25 increases.

  The operation of the refrigerant flow path opening / closing mechanism 70 and the cooling operation of the permanent magnet 25 in the permanent magnet type motor 100 of this embodiment having the structure as described above and the temperature characteristics of the permanent magnet 25 will be described.

  When the rotational speed of the rotor is low, the centrifugal force applied to the valve member 71 is smaller than the pressing force toward the center line 92 of FIG. 3 applied to the valve member 71 by the tension of the elastic member 76, and the first valve of the valve member 71. The distal end of the body part 72 enters the communication hole 28, and the tapered surface near the base hits the opening end surface on the cavity 34 side of the communication hole 28 (second refrigerant flow path), so that the communication hole 28 (second refrigerant flow path) The refrigerant flow is blocked. Therefore, the refrigerant discharged from the refrigerant supply pump 51 does not flow from the center hole 22 of the rotor shaft 21 to the through hole 31 of the rotor core 23 but is sprayed to the coil ends 42 and 43 through the refrigerant pipes 53 to 55. . As shown in FIGS. 2 and 3, in this state, the second valve body 73 is located radially inward from the opening on the cavity 34 side of the radial hole 29, and the cavity 34 and the radial hole 29. Is in communication.

As the rotational speed of the rotor 20 increases, the centrifugal force applied to the valve member 71 gradually increases. Further, since centrifugal force is also applied to the refrigerant contained in the center hole 22 of the rotor shaft 21, the pressure P of the refrigerant applied to the pressure receiving surface 75 of the valve member 71 gradually increases. In the permanent magnet type motor 100 of the present embodiment, the spot facings 36 are provided on the peripheral edge on the center hole 22 side, and the pressure receiving surface 75 has a radius in a state where the first valve body 72 is fitted in the communication hole 28. The position in the direction is the region of the guide hole 33, and is configured to be positioned radially outward from the surface of the center hole 22 or the inner surface 21 a of the rotor shaft 21. For this reason, when the rotor 20 rotates, the pressure of the refrigerant applied to the pressure receiving surface 75 is such that the refrigerant applied to the inner surface 21a of the rotor shaft 21 without the spot facings 36 or the surface of the center hole 22 (the surface of the first refrigerant flow path). It is higher than the pressure. As the rotational speed of the rotor 20 increases, the total of the centrifugal force applied to the valve member 71 and the radially outward load due to the refrigerant pressure P applied to the pressure receiving surface 75 of the valve member 71 also increases. 3 is less than or equal to r _1, the total load on the radially outer side is smaller than the pressing force applied to the valve member 71 by the tension of the elastic member 76 toward the center line 92 in FIG. The first valve body 72 is in a state where the communication hole 28 is blocked. Since the valve member 71 does not move in the radial direction, the second valve body portion 73 remains at a position radially inward from the opening on the cavity 34 side of the radial hole 29, and the cavity 34 and the radial hole 29 are It is in a state of communication.

Then, when the rotational speed of the rotor 20 further increases and the rotational speed of the rotor 20 exceeds r ₁ , the outer side in the radial direction due to the centrifugal force applied to the valve member 71 and the refrigerant pressure P applied to the pressure receiving surface 75 of the valve member 71. 3 becomes larger than the pressing force toward the center line 92 in FIG. 3 applied to the valve member 71 by the tension of the elastic member 76. Then, as shown in FIG. 4, the valve member 71 moves outward in the radial direction, and the tapered surface near the root of the first valve body 72 is located on the cavity 34 side of the communication hole 28 (second refrigerant flow path). Move away from the open end face. At this time, as shown in FIG. 4, the tip of the second valve body portion 73 has not yet entered the radial hole 29, and the opening end of the radial hole 29 on the cavity 34 side is open. Therefore, the refrigerant discharged from the refrigerant supply pump 51 passes through the communication hole 28, the cavity 34, the radial hole 29, and the axial hole 30 from the center hole 22 of the rotor shaft 21 as shown by the arrows in FIG. The permanent magnets 25 begin to cool through the through holes 31 of the 23.

When the rotational speed of the rotor 20 rises beyond r ₁ , the total of the centrifugal force applied to the valve member 71 and the radially outward load due to the refrigerant pressure P applied to the pressure receiving surface 75 of the valve member 71 is as follows: The amount of movement of the valve member 71 radially outward increases gradually. As a result, the gap between the taper surface near the base of the first valve body 72 and the opening end surface of the communication hole 28 on the cavity 34 side becomes large, and the communication from the center hole 22 of the rotor shaft 21 as shown by the arrow in FIG. The flow rate of the refrigerant flowing through the hole 28, the cavity 34, the radial hole 29, and the axial hole 30 into the through hole 31 of the rotor core 23 increases.

When the rotational speed of the rotor 20 further increases, the distal end of the second valve body 73 starts to enter the radial hole 29 due to the movement of the valve member 71 outward in the radial direction. Then, the gap between the taper surface near the base of the second valve body 73 and the opening end surface of the radial hole 29 on the cavity 34 side is gradually reduced, and the center hole 22 of the rotor shaft 21 is indicated by the arrow shown in FIG. The flow rate of the refrigerant flowing from the through hole 28 to the through hole 31 of the rotor core 23 through the communication hole 28, the cavity 34, the radial hole 29, and the axial hole 30 decreases. Thus, the clearance between the first valve body 72 and the communication hole 28 (second refrigerant flow path), that is, the opening degree of the second refrigerant flow path, is increased by the movement of the valve member 71 outward in the radial direction. Then, conversely, the gap between the second valve body portion 73 and the radial hole 29 (fourth refrigerant channel), that is, the opening degree of the fourth refrigerant channel decreases. However, when the rotational speed of the rotor 20 is less than r ₂ , the tapered surface near the root of the second valve body portion 73 is not in contact with the opening end surface of the radial hole 29 on the cavity 34 side, and the refrigerant passes through the through hole. 31 continues to flow.

When the rotational speed of the rotor 20 exceeds r ₂ , the valve member 71 is applied to the valve member 71 by the tension of the elastic member 76 due to a large centrifugal force and a radially outward load due to a pressure increase of the refrigerant applied to the pressure receiving surface 75. It overcomes the pressing force toward the center line 92 in FIG. 3 and moves further outward in the radial direction. Then, as shown in FIG. 5, the tip of the second valve body 73 enters the radial hole 29, and the tapered surface near the root is on the cavity 34 side of the radial hole 29 (fourth refrigerant flow path). The refrigerant flows through the radial hole 29 (fourth refrigerant flow path) by blocking against the opening end face. Then, the refrigerant discharged from the refrigerant supply pump 51 does not flow from the center hole 22 of the rotor shaft 21 to the through hole 31 of the rotor core 23, but is blown to the coil ends 42 and 43 through the refrigerant pipes 53 to 55. It becomes like this.

Contrary to the above, if the rotational speed of the rotor 20 is lowered from the state higher than r _2, the rotational speed is lower than r _2, a second valve body portion 73 and the radial bore 29 is circulated Thus, the refrigerant flows into the through hole 31. When the rotational speed is further reduced, the clearance between the second valve body portion 73 and the radial hole 29 (fourth refrigerant flow path), that is, the fourth refrigerant flow path, due to the movement of the valve member 71 inward in the radial direction. On the contrary, when the opening degree increases, the clearance between the communication hole 28 (second refrigerant flow path) of the first valve body 72, that is, the opening degree of the second refrigerant flow path decreases. When the rotational speed of the rotor 20 further decreases to r ₁ or less, the taper surface of the first valve body portion 72 is pressed by the pressing force toward the center line 92 of FIG. 3 applied to the valve member 71 by the tension of the elastic member 76. The communication hole 28 is cut off in contact with the opening end surface of the communication hole 28 on the cavity 34 side, and the flow of the refrigerant to the through hole 31 is cut off.

In the present embodiment, the first valve body 72 opens and closes the communication hole 28 when the rotational speed of the rotor 20 is r ₁ , and the second valve body 73 opens and closes the radial hole 29 when the rotational speed is r ₂ . As described above, the weight of the valve member 71, the area of the pressure receiving surface 75, and the tension of the elastic member 76 are adjusted. The rotational speed of the rotor 20 at which the first and second valve body portions 72 and 73 perform the opening / closing operation is adjusted by, for example, adjusting the elastic modulus of the elastic member 76, the area of the pressure receiving surface 75, etc. Adjust to fit.

As described above, the permanent magnet type motor 100 according to the present embodiment cools the permanent magnet 25 by flowing a refrigerant in the vicinity of the permanent magnet 25 in the middle rotation speed region where the temperature of the permanent magnet 25 becomes high, thereby reducing the low rotation speed. In the region and the high rotational speed region, the refrigerant flow to the vicinity of the permanent magnet 25 can be blocked. Thereby, in the low rotation speed region and the high rotation speed region, the system efficiency of the permanent magnet motor 100 is improved by reducing the discharge amount of the refrigerant supply pump 51 by suppressing the circulation of unnecessary refrigerant. be able to. Further, when the rotational speed of the rotor 20 exceeds r ₂ , the refrigerant does not flow through the through holes 31 of the rotor core 23, so that the outer surface of the rotor core 23 passes through the gap between the electromagnetic steel plates 24 stacked from the through holes 31 by centrifugal force. The torque loss characteristic of the rotor 20 due to the refrigerant leaking out and staying between the rotor core 23 and the stator core 41 changes from the state shown by the line f in FIG. 7 to the state shown by the line e. Thereby, torque loss in the high rotation speed region is greatly reduced, and the system efficiency of the permanent magnet motor 100 can be improved even in the high rotation region.

  In addition, the refrigerant flow path opening / closing mechanism 70 of the permanent magnet type motor 100 according to the present embodiment combines not only the centrifugal force applied to the valve member 71 but also the load directed outward in the radial direction due to the pressure P of the refrigerant applied to the pressure receiving surface 75. The valve member 71 is configured to move in the radial direction by a load. For this reason, as compared with the method of adjusting the flow rate of the refrigerant by moving the member in the radial direction only by the centrifugal force applied to the member as in the prior art, the rotational speed range of the rotor 20 through which the refrigerant flows is wider. The rotational speed of the rotor 20 through which the refrigerant flows can be optimized according to the size and output of the permanent magnet type motor 100, and the system efficiency can be improved. Moreover, since not only the centrifugal force but also the load due to the pressure P of the refrigerant is combined and applied to the radially outward load applied to the valve member 71, the valve member 71 is moved radially outward only by the centrifugal force of the valve member 71. Compared to the structure, the weight of the valve member 71 can be reduced, and the permanent magnet motor 100 can be reduced in size and weight. Furthermore, even if the accuracy of the shape and weight of the valve member 71 is not so high, the refrigerant flow path can be reliably opened and closed at a predetermined rotational speed, and the refrigerant flow rate for cooling the permanent magnet 25 can be accurately adjusted. In addition, it is possible to suppress variations in the refrigerant flow rate and excess / deficiency of the refrigerant flow rate, thereby suppressing a decrease in operating efficiency.

  Next, another embodiment of the present invention will be described with reference to FIG. Parts similar to those of the embodiment described above with reference to FIGS. 1 to 7 are denoted by the same reference numerals, and description thereof is omitted. As shown in FIG. 8, the permanent magnet type motor 100 of this embodiment forms a cavity 37 by cutting out the electromagnetic steel plate 24 at the center of the rotor core 23 in the direction of the rotation axis 91, and cuts a part of the electromagnetic steel plate 24. A radial hole 29 (fourth refrigerant flow path) that extends in the radial direction from the cavity 37 and communicates with the through hole 31 (third refrigerant flow path) is formed. That is, the radial hole 29 is a fourth refrigerant flow path provided in the rotor core 23. Further, the center hole 22 (first refrigerant flow path) of the rotor shaft 21, the communication hole 28 (second refrigerant flow path) communicating with the cavity 37, and the guide hole 33 are provided in the rotor shaft 21 at a position facing the cavity 37. The valve member 71 is also arranged at the approximate center of the rotor core 23 in the direction of the rotation axis 91 in accordance with the position of the guide hole 33, the communication hole 28, and the radial hole 29 in the direction of the rotation axis 91. In accordance with this, the elastic member 76 and the lug 77 are also arranged at substantially the center in the axial direction of the rotor core 23.

In the permanent magnet type motor 100 of the present embodiment, the refrigerant supplied from the first end 21 e side of the rotor shaft 21 to the center hole 22 (first refrigerant flow path) of the rotor shaft 21 is the axial center position of the rotor core 23. Until it flows through the center hole 22. When the rotational speed of the rotor 20 exceeds r ₁ and less than r _{2, both the} communication hole 28 (second refrigerant channel) and the radial hole 29 (fourth refrigerant channel) are formed by the refrigerant channel opening / closing mechanism 70. The refrigerant enters the open state, and the refrigerant is disposed in the radial hole 29 (first hole) disposed at the center position in the axial direction of the communication hole 28 (second refrigerant channel), the cavity 37 and the rotor core 23 from the center hole 22 (first refrigerant channel). The refrigerant flows into the through hole 31 (third refrigerant channel) through the four refrigerant channels. The refrigerant flowing into the through hole 31 through the radial hole 29 is divided from the position of the radial hole 29 in the direction of the first end portion 21e and the second end portion 21f of the rotor shaft 21, and the shaft passes through the through hole 31. It flows in the direction opposite to the direction, and is discharged into the casing 10 through axial holes 30 and 32 provided in the end plates 26 and 27, respectively.

  The operation of the refrigerant flow path opening / closing mechanism 70 of the present embodiment is the same as that of the embodiment described above with reference to FIGS. 1 to 7, and the effect thereof has also been described with reference to FIGS. This is the same as the embodiment.

  DESCRIPTION OF SYMBOLS 10 Casing, 11, 12 End plate, 13, 14 Ball bearing, 20 Rotor, 21 Rotor shaft, 21a Inner surface, 21b Outer surface, 21e First end, 21f Second end, 22 Center hole, 23 Rotor core, 24 Electrical steel plate , 25 Permanent magnet, 26, 27 End plate, 28 Communication hole, 29 Radial hole, 30, 32 Axial hole, 31 Through hole, 33 Guide hole, 34, 37 Cavity, 35 Projection, 36 Counterbore, 40 Stator , 41 Stator core, 42, 43 Coil end, 51 Refrigerant supply pump, 52 Refrigerant supply pipe, 53-55 Refrigerant pipe, 56-58 orifice, 61, 62 Refrigerant blowing pipe, 70 Refrigerant flow path opening / closing mechanism, 71 Valve member, 72 1st valve body part, 73 2nd valve body part, 74 guide part, 75 pressure receiving surface, 76 elastic member, 77 Lug, 91 rotating shaft, 92, 93 center line, 100 permanent magnet type motor.

Claims (7)

A rotor shaft having a first refrigerant passage extending in the axial direction therein and through which the refrigerant flows; and a second refrigerant passage communicating the first refrigerant passage and the outer surface thereof;
A rotor core made of a laminated steel plate and fixed to the outer surface of the rotor shaft;
A rotor including a permanent magnet fixed to the rotor core;
A third refrigerant flow path disposed in the vicinity of the permanent magnet and penetrating the rotor core in the axial direction;
A fourth refrigerant channel provided in the rotor and communicating the second refrigerant channel and the third refrigerant channel;
A permanent magnet type, comprising: a refrigerant channel opening / closing mechanism that is disposed between the second refrigerant channel and the fourth refrigerant channel and opens and closes the second refrigerant channel and the fourth refrigerant channel. A motor,
The refrigerant flow path opening / closing mechanism closes the second refrigerant flow path when the rotational speed of the rotor is equal to or less than a first predetermined value, and the rotational speed of the rotor is larger than the first predetermined value. The second refrigerant flow path is closed when the value is equal to or greater than a predetermined value of 2, and when the rotational speed of the rotor is greater than the first predetermined value and less than a second predetermined value, the second refrigerant is Opening both the flow path and the fourth refrigerant flow path;
Permanent magnet type motor characterized by The permanent magnet type motor according to claim 1,
The refrigerant flow path opening / closing mechanism has the second refrigerant flow path and the fourth refrigerant flow so that the increase / decrease in the opening degree of the second refrigerant flow path is opposite to the increase / decrease in the opening degree of the fourth refrigerant flow path. Changing the opening of the road,
Permanent magnet type motor characterized by The permanent magnet type motor according to claim 1 or 2,
The rotor shaft has a guide hole penetrating between an outer surface thereof and the first refrigerant flow path,
The refrigerant flow path opening / closing mechanism is
The guide includes: a first valve body portion that closes the second refrigerant flow path; a second valve body portion that closes the fourth refrigerant flow path; and a pressure receiving portion that receives the refrigerant pressure of the first refrigerant flow path. A valve member that is guided by a hole and moves in a radial direction;
An elastic member that urges the valve member in a radial direction toward the first refrigerant flow path,
Permanent magnet type motor characterized by The permanent magnet type motor according to claim 3,
When the first valve body portion of the valve member closes the second refrigerant flow path, the surface of the pressure receiving portion that receives the refrigerant pressure is positioned radially outward from the surface of the first refrigerant flow path. Being
Permanent magnet type motor characterized by The permanent magnet type motor according to claim 3 or 4,
The opening peripheral edge of the surface of the first coolant channel of the guide hole is recessed radially outward from the surface of the first coolant channel;
Permanent magnet type motor characterized by It is a permanent magnet type motor given in any 1 paragraph of Claims 1-5,
The fourth refrigerant channel is a channel provided in the rotor core and extending in a radial direction;
Permanent magnet type motor characterized by It is a permanent magnet type motor given in any 1 paragraph of Claims 1-5,
The fourth coolant channel is a channel provided outside the rotor core and extending in a radial direction;
Permanent magnet type motor characterized by

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