JP4852959B2 - Axial type motor and cooling method - Google Patents

Description

  The present invention relates to a motor having a cooling function, and more particularly, to an axial type motor in which a rotor and a stator are arranged to face each other in a direction parallel to a rotation axis, and a method for cooling the motor.

  2. Description of the Related Art Conventionally, an axial type motor in which a disk-shaped rotor and a stator are arranged to face each other is widely known. This axial motor is used in various applications such as an electric vehicle because it is relatively easy to downsize. It is known that these motors generate heat by generating Joule heat or the like from the coil during operation. When the temperature of the motor rises due to such heat generation, there arises a problem that the operation efficiency is lowered. In particular, in the case of a permanent magnet type motor using a permanent magnet, the magnetic force of the permanent magnet is reduced by the temperature rise, so that it is desirable to prevent the temperature rise of the motor as much as possible. Further, the increase in the temperature of the motor not only causes a decrease in operating efficiency, but also causes a problem that the life of the motor is decreased, specifically, the coil and the stator core are deteriorated.

  Therefore, many motor cooling techniques have been proposed. For example, Patent Document 1 discloses a flat AC motor that fills a motor case with a refrigerant and circulates the refrigerant. Patent Document 2 discloses a motor in which a lubricating oil passage that is a passage for lubricating oil is formed in a rotor. In this motor, the supplied lubricating oil is guided to the lubricating oil path by utilizing the centrifugal force accompanying the rotation of the rotor, and the rotor is cooled with this lubricating oil.

JP-A-10-243617 JP 2003-169448 A

  However, in the technique of Patent Document 1, the rotor is rotationally driven in the refrigerant filled in the case. In this case, the rotor receives resistance from the refrigerant, causing a loss called dragging loss, which reduces the efficiency of the motor. In the technique of Patent Document 2, it is necessary to form a path for circulating the refrigerant. As a result, not only the configuration of the motor becomes complicated, but also problems such as an increase in cost occur. Further, since the contact area between the refrigerant and the rotor, that is, the cooling area is small, the cooling efficiency is also low.

  Accordingly, an object of the present invention is to provide an axial type motor and a cooling method that can perform efficient cooling with a simple configuration.

An axial type motor of the present invention includes a substantially disk-shaped rotor, a plurality of teeth around which coils are wound, a stator disposed to face the rotor via a predetermined gap, and a case for housing the rotor and the stator And an inlet that guides refrigerant injected from outside the case to the inner peripheral end of the gap, and refrigerant carried from the inner peripheral end to the outer peripheral end of the gap by rotation of the rotor. And at least the stator is formed with an opening groove that expands the volume of the end portion on the inner peripheral side of the gap .

In a preferred embodiment, the open Kuchimizo is preferably shaped to reduce the height of the gap toward the outer peripheral side. For example, it is desirable that the bottom surface of the opening groove has a tapered shape inclined toward the inner peripheral side.

Opening groove provided in the scan stator side have a shape that guides the coolant to the rotor surface still desirable. For example, it is desirable that the rear end surface of the opening groove provided on the stator side is substantially perpendicular to the rotor surface. It is also desirable that the side surface of the opening groove provided on the stator side is substantially perpendicular to the rotor surface.

  In another preferred aspect, the stator has a substantially flat surface facing the rotor. For example, the stator desirably includes a connection member that is disposed in a slot space between the teeth and covers the upper surface of the slot space. It is still desirable if the connecting member is formed with an opening groove that expands the volume of the inner peripheral end of the gap.

  In another preferred aspect, the facing surface of the rotor has higher wettability with respect to the refrigerant than the facing surface of the stator.

  In another preferred aspect, the stator includes a connection member disposed in a slot space between the teeth and covering an upper surface of the slot space, and the connection member includes the connection member as the rotor rotates. One or more guide openings for guiding a part of the refrigerant conveyed to the outer peripheral side end of the gap in the coil direction are provided. In this case, the guide opening is preferably a through hole inclined in a predetermined direction with respect to the rotation axis. The guide opening is preferably a long hole.

Another cooling method according to the present invention is a cooling method for an axial-type motor including a substantially disk-shaped rotor, a stator disposed to face the rotor via a predetermined gap, and a case for housing the rotor and the stator. An inner peripheral end having a volume expanded by an opening groove formed at least on an inner peripheral end of the stator, out of the gap, from the outside of the case through an inlet provided in the case. The refrigerant is conveyed to the outer peripheral side end of the gap due to the pressure difference in the gap caused by the rotation of the rotor, and the refrigerant discharged from the outer peripheral side end of the gap is discharged through the discharge port provided in the case. It is characterized by discharging outside the case.

  In a preferred embodiment, the amount of refrigerant injected from the inlet is an amount that does not fill the inside of the case with the refrigerant. More desirably, the amount of refrigerant injected from the injection port is such an amount that the gap is not filled with the refrigerant.

  In another preferred aspect, a part of the refrigerant carried to the outer peripheral side end portion of the gap as the rotor rotates is passed through one or more guide openings formed in a part of the stator in the coil direction. By guiding, the coil is also cooled.

  According to the present invention, since the refrigerant is transported using the rotating action of the rotor, a refrigerant passage or the like is not necessary. Moreover, since the inside of the case is not filled with the refrigerant, drag loss and the like can be reduced. As a result, efficient motor cooling is possible with a simple configuration.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic sectional view of an axial motor 10 according to an embodiment of the present invention. FIG. 2 is a cross-sectional view taken along the line AA in FIG. The arrows in FIGS. 1 and 2 indicate the flow of the refrigerant 20 described later.

  The rotating shaft 12 of the motor 10 is rotatably fixed to the case 18 by a bearing or the like (not shown). A rotor 14 is fixed to the rotary shaft 12 and rotates together with the rotary shaft 12. The rotor 14 has a substantially disk shape, and a plurality of permanent magnets (not shown) are arranged inside the rotor 14.

  On the other hand, two substantially annular stators 16 are arranged inside the case 18 so as to sandwich the disk-shaped rotor 14. That is, each stator 16 is disposed to face the rotor 14 via a predetermined gap 22. A plurality of teeth 26 projecting toward the rotor 14 are formed on the stator 16. A conductive wire is wound around each tooth 26 to form a coil 28, and a magnetic pole is formed. Then, the electric pole is sequentially passed through the coil 28 to magnetize the teeth 26 and form a rotating magnetic field. As a result, the permanent magnet of the rotor 14 interacts with the rotating magnetic field, so that the rotor 14 rotates and power can be obtained.

  Here, when the coil 28 is energized and the motor 10 is operated, the temperature rises due to Joule heat or the like. On the other hand, the iron core of the rotor 14 generates heat due to eddy currents, resulting in an increase in the temperature of the rotor 14. When the temperature rises, the magnetic force of the permanent magnet of the rotor 14 is lowered, and the operation efficiency of the motor 10 is lowered. Further, there is a problem that the temperature rise causes a reduction in the life of the coil 28 and the like. In order to prevent these problems, it is necessary to cool the rotor 14 and the stator 16 efficiently. Therefore, in the present embodiment, the refrigerant 20 that is a liquid for cooling the motor 10 is circulated over the entire surface of the rotor 14 and the stator 16 by utilizing the rotating action of the rotor 14. This will be described in detail below.

  One of the features of the present embodiment is that the coolant 20 that is a cooling liquid is supplied to the gap 22 that exists between the rotor 14 and the stator 16. Specifically, the refrigerant 20 is injected from an inlet 24 provided in the case 18. A plurality of inlets 24 are provided around the rotary shaft 12 (four examples are shown in FIGS. 1 and 2), and the refrigerant 20 supplied from the outside of the case 18 is supplied to the inner peripheral side end 22a of the gap 22. Lead. The refrigerant 20 that has reached the inner peripheral side end 22 a of the gap 22 is guided to the outer peripheral side by the rotating action of the rotor 14. That is, a substantially annular gap 22 is formed between the substantially disk-shaped rotor 14 and the substantially annular stator 16. When the rotor 14 rotates at a high speed, a pressure difference is generated between the inner peripheral side and the outer peripheral side of the gap 22. Specifically, the inner peripheral side of the gap 22 has a high pressure, and the outer peripheral side of the gap 22 has a low pressure. Due to this internal / external pressure difference, the refrigerant 20 that has reached the inner peripheral end of the gap 22 is transported to the outer peripheral side. During the movement from the inner peripheral side to the outer peripheral side, the refrigerant 20 comes into contact with the surface of the rotor 14 and the surface of the stator 16 and removes heat therefrom. As a result, the rotor 14 and the stator 16 are cooled, and a reduction in operating efficiency of the motor 10 is prevented. The refrigerant 20 that has reached the outer peripheral side end 22b of the gap 22 is discharged into the space 19 formed between the case 18, the rotor 14, and the stator 16, and then falls below the case 18 due to gravity. The dropped refrigerant 20 is discharged to the outside of the case 18 from a discharge port 25 formed at the lower end of the case 18.

  As is apparent from the above description, in the present embodiment, the refrigerant 20 is supplied to the gap 22 between the rotor 14 and the stator 16, and the refrigerant 20 is rotated from the inner peripheral side to the outer periphery by utilizing the rotational action of the rotor 14. It is moved to the side. This eliminates the need for a dedicated route for transporting the refrigerant. As a result, the configuration of the motor 10 can be simplified and the cost can be reduced. Further, since the refrigerant 20 directly contacts the surfaces of the rotor 14 and the stator 16, a high cooling effect can be obtained.

  Here, the amount of the refrigerant 20 to be supplied is desirably an amount that does not allow the inside of the case 18 to be filled with the refrigerant 20. Furthermore, it is still desirable if the amount is such that the gap 22 cannot be filled with the refrigerant 20. That is, when the inside of the case 18 is filled with the refrigerant 20 that is a liquid, shearing stress acts on the refrigerant 20 by the rotation of the rotor 14. This shear stress becomes an energy loss of the motor 10, a so-called drag loss, and causes a reduction in the operation efficiency of the motor. Further, even when the inside of the gap 22 is filled with the refrigerant 20 that is a liquid, the shear stress works even though the value is low, resulting in drag loss. In order to prevent or reduce the drag loss, the amount of the supplied refrigerant 20 is set to an amount that does not fill the inside of the case 18, more preferably, the inside of the gap 22 with the refrigerant 20. It is desirable.

  In order to prevent the inside of the case 18 from being filled with the refrigerant 20, the amount of refrigerant supplied within the unit time may be made smaller than the amount of refrigerant discharged from the discharge port 25 within the unit time. In order to prevent the inside of the gap 22 from being filled with the refrigerant 20, the amount of refrigerant supplied within the unit time is set to the amount of refrigerant released from the outer peripheral end 22b of the gap 22 within the unit time. Less. Since the amount of refrigerant discharged from the outer peripheral side end 22b of the gap 22 can be estimated based on the rotational speed of the rotor 14 or the like, the amount of refrigerant to be supplied may be estimated based on the rotational speed of the rotor 14 or the like. .

  By the way, in order to realize efficient cooling, it is desirable that all of the supplied refrigerant 20 pass through the gap 22. Further, it is necessary that a sufficient pressure difference is generated between the inner peripheral side and the outer peripheral side of the gap 22. In order to satisfy such conditions, in the present embodiment, the upper surface of the stator 16 is a substantially flat surface. This will be described with reference to FIGS. FIG. 3 is a perspective view of a stator 16 used in a typical axial motor 10, and FIG. 4 is a partial perspective view of the stator 16 in the present embodiment.

  In the normal axial type motor 10, as shown in FIG. 3, a stator 16 in which a plurality of teeth 26 are arranged to protrude is used. A gap extending to the bottom surface, that is, a so-called slot 30 is formed between the teeth 26. A coil 28 is wound around each tooth 26 using the space of the slot 30. However, the coil 28 is not wound up to the top surface of the tooth 26 but often ends in the middle. In addition, a gap is easily generated between the coil 28 wound around the adjacent tooth 26 and the coil 28. That is, in the case of the conventional stator 16, the upper surface was not flat and there were many unevenness | corrugations. Thus, when there are many irregularities on the upper surface of the stator 16, there is a problem that the refrigerant 20 supplied to the gap 22 is not properly conveyed to the outer peripheral end of the gap 22.

  That is, in the conventional stator 16, the gap 22, that is, a part of the refrigerant 20 supplied above the stator 16 falls into the slot 30 space due to gravity or hydraulic pressure, and reaches the outer peripheral end 22 b of the gap 22. There was a case not to. Further, since the slot 30 space and the gap 22 communicate with each other, there is a problem that a pressure difference between the inner peripheral side and the outer peripheral side of the gap 22 does not easily occur, and the transporting ability of the refrigerant 20 decreases.

  Therefore, in the present embodiment, as illustrated in FIG. 4, a connection member 32 that connects between the teeth 26 is provided. The connection member 32 is a member disposed between the teeth 26 so that the upper surface of the stator 16 is substantially flat. The connection member 32 is preferably made of a nonmagnetic material so as not to affect the magnetic field generated in the stator 16. Or you may interpose the tape which consists of nonmagnetic materials in the contact part with the teeth 26. FIG. The connection member 32 has a cross section having the same shape as the cross section of the slot 30 and can completely cover the upper surface of the slot 30. The connecting member 32 is fixed by fixing means (not shown) so that the upper surface height is the same as the upper surface height of the teeth 26. However, the thickness of the connecting member 32 is smaller than the thickness of the tooth 26. Therefore, when the upper surface height of the teeth 26 and the upper surface height of the connection member 32 are matched, a space is formed below the connection member 32. The coil 28 is wound around the teeth 26 using this space.

  By providing the connection member 32, the upper surface of the stator 16 becomes a substantially flat surface, and the falling of the refrigerant 20 supplied to the gap 22 is prevented. The gap 22 is a semi-closed space opened only at the outer peripheral end and the inner peripheral end. Therefore, a large pressure difference is generated between the outer peripheral side and the inner peripheral side of the gap 22 due to the rotating action of the rotor 14, and a large refrigerant transport force is obtained.

  Furthermore, in this embodiment, an opening groove 34 is provided at the inner peripheral side end of the connection member 32. This will be described with reference to FIGS. 5 is a cross-sectional view taken along the line BB in FIG. 4, and FIG. 6 is an enlarged view of a portion C in FIG.

  As shown in FIG. 5, an opening groove 34 is formed at the inner peripheral side end of the connection member 32. Due to the opening groove 34, the inner peripheral end 22 a of the gap 22 is greatly expanded. Here, the refrigerant 20 is supplied to the inner peripheral end 22 a of the gap 22, and is conveyed to the outer peripheral side of the gap 22 through the inner peripheral end 22 a. Therefore, the inner peripheral end 22 a of the gap 22 is an inlet of the refrigerant 20 supplied into the gap 22. By widening the inlet of the refrigerant 20, the refrigerant 20 is prevented from staying near the inlet, and the refrigerant 20 can be efficiently transported.

  That is, normally, the fluid flowing into a certain space is drastically reduced in volume near the entrance of the space, so that the flow velocity is greatly reduced, and in some cases, a vortex is formed near the entrance. When such a decrease in flow velocity occurs, the transport efficiency of the refrigerant 20 decreases, and as a result, the cooling efficiency decreases. However, in the present embodiment, since the inner peripheral side end 22a of the gap 22, that is, the inlet of the refrigerant 20, is widened by the opening groove 34, the refrigerant can be efficiently transported without causing a decrease in the flow velocity. It becomes possible.

  The opening groove 34 is elongated in the radial direction. As the refrigerant 20 flows along the opening groove 34, a radial flow is generated in the refrigerant 20, and the refrigerant 20 is quickly transported to the outer peripheral side end 22 b of the gap 22. As a result, the amount of refrigerant staying in the gap 22 is reduced, and drag loss can be reduced. In the present embodiment, the opening groove 34 is provided in the connection member 32. However, as long as the inner peripheral side end 22a of the gap 22 widens, the opening groove may naturally be provided in another part. For example, a groove may be provided on the upper surface of the tooth 26 or the surface of the rotor 14. However, when a groove is provided on the upper surface of the tooth 26, it is provided at a position that does not affect the magnetic field. Moreover, when providing in the surface of the rotor 14, the several groove | channel of the same shape is provided equally so that the rotation balance of the rotor 14 may not be broken.

  The opening groove 34 of the present embodiment has a substantially fan shape when viewed from the top. This is to match the shape of the teeth 26 and the like. Therefore, the width W of the opening groove 34 gradually increases toward the outer peripheral side. In order to match the increase in the groove width W, the opening groove 34 of the present embodiment has a shape in which the groove depth H gradually decreases toward the outer peripheral side, specifically, a tapered shape inclined toward the inner peripheral side. Has a bottom surface 34a. Thus, the change in the circumferential cross-sectional area is prevented by gradually decreasing the groove depth H toward the outer peripheral side. In other words, when the bottom surface of the opening groove is horizontal, the circumferential cross-sectional area increases as it goes toward the outer peripheral side. When the sectional area of the space gradually increases in this way, a so-called expansion loss occurs in which the flow velocity of the fluid passing through the space gradually decreases. In the present embodiment, in order to prevent this expansion loss, the groove depth H is decreased as the groove width W increases.

  Further, the amount of the refrigerant 20 toward the surface of the rotor 14 can be increased by inclining the bottom surface of the opening groove 34 toward the inner peripheral side. As described, the magnetic force of the permanent magnet provided in the rotor 14 decreases as the temperature increases. Therefore, the cooling of the rotor 14 is extremely important for improving the operation efficiency of the motor 10. Therefore, in the present embodiment, the tapered bottom surface of the opening groove 34 is inclined toward the inner peripheral side, in other words, the shape approaches the surface of the rotor 14 toward the outer peripheral side. As a result, a force in the direction of the rotor 14 acts on the refrigerant 20, and the amount of refrigerant in contact with the rotor 14 surface can be increased. As a result, the cooling efficiency of the rotor 14 can be improved.

  Furthermore, in this embodiment, the outer peripheral side end face of the opening groove 34, that is, the rear end face 34 b is a standing wall substantially parallel to the rotating shaft 12. By making the rear end face 34b substantially parallel to the rotary shaft 12, the refrigerant 20 that has collided with the rear end face 34b jumps up in the direction of the rotary axis, in other words, toward the surface of the rotor 14. As a result, the amount of the refrigerant 20 that contacts the surface of the rotor 14 increases, and the cooling efficiency of the rotor 14 can be improved.

  Further, the side surface 34 c of the opening groove 34, that is, the side surface of the tooth 26 is also a standing wall substantially parallel to the rotating shaft 12. As a result, a force in the rotation axis direction acts on the refrigerant 20 that has collided with the side surface 34c. That is, the refrigerant 20 in which the circumferential flow velocity vector has been operated by the rotating centrifugal force collides with the side surface 34c, whereby the circumferential flow velocity vector is converted into the rotational axis flow velocity vector. As a result, the amount of refrigerant that contacts the surface of the rotor 14 increases, and the cooling efficiency of the rotor 14 can be further improved.

  It should be noted that the shape of the opening groove 34 is an example, and other shapes may of course be used. For example, as shown in FIG. 7A, the connecting portion 34d between the bottom surface 34a and the rear end surface 34b of the opening groove 34 may be formed in an arc shape. By adopting such a shape, the flow direction of the refrigerant 20 can be changed more smoothly (from the radial direction to the rotation axis direction), and more efficient rotor 14 cooling can be achieved. Moreover, as shown to FIG. 7 (B), it is good also as a shape which continues inclining to the upper surface of the connection member 32, ie, a shape without a rear-end surface. By setting it as this shape, the force which goes to the surface of the rotor 14 continues to the refrigerant | coolant 20 works. As a result, a large amount of the refrigerant 20 comes into contact with the surface of the rotor 14 and the cooling efficiency of the rotor 14 can be improved. Alternatively, as shown in FIG. 8, the opening groove 34 may be configured with a two-step inclination, and the rotor 14 may be inclined according to this inclination. Thereby, the refrigerant | coolant 20 will go to the surface of the rotor 14 more reliably, and the cooling efficiency of a rotor can be improved.

  Furthermore, in order to improve the cooling efficiency of the rotor 14, in this embodiment, the wettability of the rotor 14 surface with respect to the refrigerant 20 is made higher than that of the stator 16 surface. The wettability with respect to the refrigerant 20 is a parameter indicating the contact property with the refrigerant 20, the holding power of the contacted refrigerant 20, etc., and the higher the wettability, the higher the contact property with the refrigerant 20. High holding power. By making the wettability of the surface of the rotor 14 higher than that of the stator 16, more refrigerant 20 comes into contact with the rotor 14, and the cooling efficiency of the rotor 14 can be further improved.

  This wettability can be easily changed by coating or the like. Therefore, when the refrigerant 20 is oily, an oil-repellent coating (for example, fluorine coating or the like) may be applied to the surface of the stator 16. Further, when the coolant is aqueous, the surface of the stator 16 may be provided with a water repellent coating (for example, fluorine coating). Or conversely, the surface of the rotor 14 may be provided with a lipophilic or hydrophilic coating.

  Next, the cooling effect of this embodiment will be described. First, the effect of providing the opening groove 34 will be briefly described. FIG. 9A schematically shows the flow of the refrigerant when there is no opening groove 34, and FIG. 9B schematically shows the flow of the refrigerant 20 when the opening groove 34 is provided. As is clear from FIG. 9, when there is no opening groove 34, the refrigerant 20 supplied from the inlet 24 temporarily stays at the inner peripheral end 22 a of the gap 22 and then reaches the inside of the gap 22. At this time, a circumferential force directly received from the rotating rotor 14 and a radial force due to a pressure difference in the gap 22 are generated in the refrigerant 20. In response to both forces, the refrigerant 20 moves while drawing a spiral trajectory centered on the rotating shaft 12.

  On the other hand, when the opening groove 34 is provided, the refrigerant 20 supplied from the inlet 24 is smoothly guided to the inside of the gap 22 without staying at the inner peripheral side end 22 a of the gap 22. In addition, at the inner peripheral end 22 a of the gap 22, the refrigerant 20 flows along the opening groove 34 that is long in the radial direction, so that a radial force is generated in the refrigerant 20. That is, when there is the opening groove 34, the refrigerant 20 has a circumferential force directly received from the rotating rotor 14, a radial force due to a pressure difference in the gap 22, and further along the opening groove 34. A radial force generated by flowing is generated. As a result, the refrigerant 20 can flow substantially in the radial direction, and can reach the outer peripheral side end 22b of the gap 22 in a shorter time than when the opening groove 34 is not provided. In other words, the residence time of the refrigerant 20 in the gap 22 is shortened. Thereby, even if a large amount of the refrigerant 20 is supplied, the gap 22 is not filled with the refrigerant 20, and drag loss can be reduced. Further, since the refrigerant 20 is discharged to the outside of the gap 22 in a short time, a large amount of the refrigerant 20 can be supplied, and the flow rate of the refrigerant 20 in the gap 22 can be increased. As a result, the cooling efficiency can be further improved.

  FIG. 10 is a graph showing the difference in flow rate depending on the presence or absence of the opening groove 34. In FIG. 10, the broken line indicates the case where there is no opening groove 34, and the solid line indicates the case where there is an opening groove 34. In addition, the horizontal axis indicates the rotational speed of the rotor 14, and the vertical axis indicates the amount of the refrigerant 20 that has passed through a predetermined position inside the gap 22 within a unit time, that is, the flow rate. As can be seen from FIG. 10, when the opening groove 34 is provided, the diversion of the refrigerant 20 is greatly increased. This is because the flow rate of the refrigerant 20 is significantly increased by providing the opening groove 34.

  FIG. 11 is a graph showing the difference in drag loss depending on the presence or absence of the opening groove 34. In FIG. 11, the broken line indicates the case where there is no opening groove 34, and the solid line indicates the case where there is an opening groove 34. Further, the horizontal axis represents the rotation speed of the rotor 14 and the vertical axis represents the loss (drag loss) generated in the motor 10. As can be seen from FIG. 11, when the opening groove 34 is provided, the drag loss is greatly reduced. This is because the flow rate of the refrigerant 20 is increased by providing the opening groove 34, and as a result, the amount of the refrigerant existing in the gap 22 is decreased.

  Next, the cooling effect of the rotor 14 will be described with reference to FIG. 12A shows the rotor 14 when cooling is not performed, FIG. 12B shows the case where cooling is performed without the opening groove 34, and FIG. 12C shows the rotor 14 when cooling is performed with the opening groove 34 provided. It is a figure which shows temperature distribution. In FIG. 12, the higher the temperature, the darker the color.

  As is apparent from FIG. 12, it can be seen that the rotor 14 is significantly cooled by supplying the coolant 20 into the gap 22. However, when there is no opening groove 34, the central part of the rotor 14 (near the inner peripheral side end of the gap 22) is cooled to some extent, but the inner part slightly from the outer peripheral side, that is, the inner peripheral side end of the gap 22 It can be seen that the cooling effect is low for the portion away from both 22a and the outer peripheral end 22b. This is because the movement path of the refrigerant 20 becomes longer because the opening groove 34 is not provided. That is, the refrigerant 20 absorbs heat from the rotor 14 and the stator 16 as it moves through the gap 22. If the moving path of the refrigerant 20 becomes long, the heat absorption capacity decreases during the movement, and the rotor 14 cannot be sufficiently cooled. As a result, proper rotor cooling cannot be performed, and the temperature of the portion where heat is most likely to be accumulated rises.

  On the other hand, when the opening groove 34 is provided, the moving path of the refrigerant 20 is short and the flow rate of the refrigerant 20 is large as shown in FIG. As a result, the refrigerant 20 is transported to the outer peripheral side end 22b of the gap 22 while maintaining a sufficient heat absorption capability. As a result, the entire surface of the rotor 14 can be appropriately cooled.

  As described above, according to the present embodiment, the motor can be cooled with a simple configuration without reducing the operation efficiency of the motor. In particular, by providing the opening groove 34 and widening the inner peripheral side end 22a of the gap 22, more effective cooling can be achieved, and the energy loss of the motor can be further reduced.

  In addition, the said embodiment is an example, and if it is the structure which can supply a refrigerant | coolant from the inner peripheral side edge part 22a of the gap 22, another structure may be sufficient. Therefore, in some cases, the opening groove 34 may not be provided. Further, the wettability of the rotor and the stator surface may be the same. Further, there may be no connection member for making the surface of the stator substantially flat, and the slot space may be open to the gap 22 in some cases. In the above embodiment, the connecting member 32 is a separate member from the tooth 26, but the connecting member 32 may be formed integrally with the tooth 26. For example, as shown in FIG. 13, an overhanging portion 40 that protrudes left and right above the teeth 26 and functions as a connecting member is formed, an opening groove 34 is provided in the overhanging portion 40, and a coil 28 is provided below the overhanging portion 40. May be wound.

  Next, another embodiment will be described with reference to FIG. FIG. 14 is a partial perspective view of a stator 16 in an axial type motor that is another embodiment. In this embodiment, the stator 16 is disposed to face the rotor 14 and the coolant 20 is supplied to the gap 22 between the rotor 14 and the stator 16, as in the above-described embodiment. When the rotor 12 rotates, the refrigerant is transported by a pressure difference generated at the inner peripheral end 22a and the outer peripheral end 22b of the gap 22 or a centrifugal force generated by the rotor rotation. Thereby, cooling of the rotor 12 is implement | achieved.

  Further, in the present embodiment, the configuration of the stator 16 is changed from that of the above-described embodiment in order to guide a part of the conveyed refrigerant 20 in the direction of the coil 28 and to cool the coil 28 simultaneously with the cooling of the rotor 14. . This will be explained in detail.

  Also in the present embodiment, the connection member 32 is provided between the teeth 26 of the stator 16 and the upper surface of the stator 16 is a substantially flat surface. The coil 28 is wound around the tooth 26 using a space formed below the connection member 32.

  In the present embodiment, the connection member 32 is provided with a guide opening 50 for guiding a part of the conveyed refrigerant 20 in the direction of the coil 28. The guide opening 50 is a through hole provided in the connection member 32 and extending from the upper surface of the connection member 32 toward the coil 28. The shape, number, and size of the guide opening 50 are not particularly limited, but FIG. 14 illustrates a round hole that extends vertically downward as the guide opening 50. A part of the refrigerant 20 supplied to the gap 22 is guided toward the coil 28 by the guide opening 50.

  Next, the flow of the refrigerant 20 in the axial motor 10 using the stator 16 will be described with reference to FIG. FIG. 15 is a cross-sectional view of the axial type motor 10 at a position corresponding to DD in FIG.

  Also in this embodiment, similarly to the above-described embodiment, the refrigerant 20 is supplied from the inlet 24 to the inner peripheral side end 22a of the gap. A part of the refrigerant 20 supplied to the inner peripheral side end 22a of the gap collides with the surface of the rotor 14 and is atomized. Moreover, a part of the refrigerant 20 forms a liquid film on the surface of the rotor 14 without being atomized, and is rotated and conveyed together with the rotor 14. In the process of this rotational conveyance, the refrigerant 20 that has been present as a liquid film is also atomized. The atomized refrigerant 20 is transported to the gap outer peripheral end 22b by the pressure difference inside the gap 22 and the centrifugal force generated by the rotation of the rotor 14. In the course of this conveyance, the refrigerant 20 directly contacts the rotor surface. Therefore, a high rotor cooling effect can be obtained. The refrigerant 20 involved in the rotor cooling is finally discharged from the outer peripheral end 22b of the gap to the outside of the gap 22, and is discharged to the outside from the discharge port 25 provided in the case 18.

  On the other hand, part of the refrigerant 20 that has bounced off the surface of the rotor 14 reaches the surface of the stator 16 when the refrigerant 20 is injected or during the conveyance process of the refrigerant 20. A part of the refrigerant 20 on the surface of the starter 16 is conveyed to the outer peripheral end 22b by being dragged by the refrigerant liquid film on the surface of the rotating rotor 14. Therefore, the conveyance speed of the refrigerant 20 that contacts the stator 16 surface is slower than that of the refrigerant 20 that contacts the rotating rotor 14 surface. Therefore, the refrigerant 20 in contact with the surface of the stator 16 is conveyed to the outer peripheral side end 22b at a slow speed while generating a swirling radial flow.

  In the course of this conveyance, the refrigerant 20 on the surface of the stator 16 falls into the guide opening 50 and is guided to the coil 28. The refrigerant 20 guided to the coil 28 flows while in direct contact with the coil 28, and is finally discharged from the discharge port 25 provided in the case 18. At this time, since the refrigerant 20 directly contacts the coil, a high coil cooling effect is obtained. As a result, high efficiency of the motor can be realized.

  Here, the refrigerant 20 used for coil cooling is the refrigerant 20 that rebounds on the surface of the rotor 14 and reaches the surface of the stator 16. In other words, the refrigerant 20 originally did not contribute to rotor cooling. By using the refrigerant 20 for coil cooling, coil cooling can be realized without lowering the rotor cooling efficiency.

  Further, when the gap 22 is filled with the refrigerant 20, a part of the rotational force of the rotor 14 becomes a shearing stress to the refrigerant 20, and so-called energy loss called drag loss occurs. In the present embodiment, since the excess refrigerant 20 is guided to the coil 28, refrigerant saturation in the gap 22 is less likely to occur. As a result, the efficiency reduction of the motor 10 can be prevented more reliably.

  In the present embodiment, the guide opening 50 is formed in the connection member 32 that is a member used for rotor cooling, and the refrigerant 20 is guided to the coil 28. Therefore, it is not necessary to provide a member dedicated to coil cooling again. That is, according to the present embodiment, both rotor cooling and coil cooling can be realized with a simple configuration.

  As is apparent from the above description, according to this embodiment, the coil 28 can be cooled with a simple configuration without reducing the cooling efficiency of the rotor 14. As a result, the driving efficiency of the motor 10 can be further improved.

  In the present embodiment, only a simple round hole is illustrated as the guide opening 50, but other shapes may naturally be used. For example, a long hole as illustrated by reference numeral 50a in FIG. 16 may be used as a guide opening. In this case, the guide opening 50b is desirably a long hole that is long in the radial direction of the stator. If the hole is long in the radial direction of the stator, a large amount of the refrigerant 20 can be guided to a wide area of the coil 28. As a result, the coil cooling efficiency can be further improved.

  Further, a through hole inclined with respect to the rotation axis as illustrated by reference numeral 50b in FIG. 16 may be used as the guide opening. By making the guide opening 50b an inclined through hole, the flow in the inclined direction can be imparted to the refrigerant 20 guided to the coil 28. In other words, the flow of the refrigerant guided to the coil 28 can be adjusted by adjusting the inclination direction of the guide opening 50b, and the refrigerant 20 can be guided to a desired position. By adjusting the position where the refrigerant 20 is guided and guiding the refrigerant 20 to a position where the coil 20 can be efficiently cooled by the coil, the cooling efficiency of the coil can be further improved.

  In addition, as described above, a swirling radiation flow is generated in the refrigerant 20 in contact with the stator surface. In other words, a flow in the circumferential direction (direction of arrow S in FIG. 16) is applied to the refrigerant 20 that contacts the stator surface. The guide opening may have a shape that does not hinder the flow in the circumferential direction. Specifically, as illustrated by reference numeral 50c in FIG. 16, a through hole 50c inclined in the same direction as the flow direction S of the refrigerant 20 on the stator surface may be used as a guide opening. With this configuration, the flow rate of the refrigerant 20 guided to the coil 28 can be improved, and consequently the flow rate of the refrigerant 20 can be improved. As a result, coil cooling efficiency can be improved.

It is a schematic sectional drawing of the axial type motor which is embodiment of this invention. It is AA sectional drawing in FIG. It is a partial perspective view of the stator in the conventional axial type motor. It is a partial perspective view of the stator of this embodiment. It is BB sectional drawing in FIG. It is the C section enlarged view in FIG. It is a figure which shows the other example of the shape of an opening groove | channel. It is a figure which shows the other example of the shape of a stator and a rotor. It is a figure which shows the flow locus | trajectory of a refrigerant | coolant, (A) shows the case where there is no opening groove, (B) shows the case where there is an opening groove. It is a graph which shows the difference in the flow volume of the refrigerant | coolant by the presence or absence of an open groove. It is a graph which shows the difference of the drag loss by the presence or absence of an opening groove | channel. It is a figure which shows the cooling efficiency of a rotor, (A) shows the case where there is no cooling, (B) shows the case where it cools without an opening groove, (C) shows the case where it cools with an opening groove. It is a figure which shows the other example of the shape of a stator. It is a fragmentary perspective view of the stator of the axial type motor which is other embodiment. It is sectional drawing of the axial type motor in other embodiment. It is a figure which illustrates the other form of the opening for guidance.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Axial type motor, 12 Rotating shaft, 14 Rotor, 16 Stator, 18 Case, 20 Refrigerant, 22 Gap, 24 Inlet, 25 Outlet, 26 Teeth, 28 Coil, 30 Slot, 32 Connection member, 50 Guide opening.

Claims (17)

A substantially disk-shaped rotor;
A stator comprising a plurality of teeth around which a coil is wound, and a stator disposed to face the rotor via a predetermined gap;
A case for housing the rotor and the stator;
An inlet for guiding the refrigerant injected from the outside of the case to the inner peripheral end of the gap;
A discharge port for discharging the refrigerant carried from the inner peripheral end of the gap to the outer peripheral end by rotation of the rotor to the outside of the case;
Equipped with a,
At least the stator is formed with an opening groove that expands the volume of the inner peripheral end of the gap.
Axial type motor characterized by that. The axial type motor according to claim 1 ,
The axial groove motor is characterized in that the opening groove has a shape that decreases the height of the gap toward the outer peripheral side. The axial type motor according to claim 2 ,
An axial type motor characterized in that the bottom surface of the opening groove has a tapered shape inclined toward the inner peripheral side. An axial type motor according to any one of claims 1 to 3 ,
The axial groove motor is characterized in that the opening groove provided in the stator has a shape for guiding the refrigerant to the rotor surface. The axial type motor according to claim 4 ,
An axial type motor characterized in that the rear end surface of the opening groove provided in the stator is substantially perpendicular to the rotor surface. An axial type motor according to claim 4 or 5 ,
An axial type motor characterized in that the side surface of the opening groove provided in the stator is substantially perpendicular to the rotor surface. A axial type motor according to claims 1 6,
The stator is an axial motor characterized in that a surface facing the rotor is a substantially flat surface. The axial type motor according to claim 7 ,
The stator is provided in a slot space between the teeth and has a connecting member that covers an upper surface of the slot space. The axial type motor according to claim 8 ,
An axial motor characterized in that an opening groove is formed in the connecting member to increase the volume of the inner peripheral side end of the gap. An axial type motor according to any one of claims 1 to 9 ,
An axial type motor characterized in that the facing surface of the rotor has higher wettability to the refrigerant than the facing surface of the stator. A cooling method for an axial type motor, comprising: a substantially disk-shaped rotor; a stator disposed to face the rotor via a predetermined gap; and a case for accommodating the rotor and the stator,
Through the inlet provided in the case, the refrigerant is guided from the outside of the case to the inner peripheral side end portion whose volume is expanded by an opening groove formed in at least the inner peripheral side end portion of the stator, among the gaps,
Due to the pressure difference in the gap caused by the rotation of the rotor, the refrigerant is transported to the outer peripheral end of the gap,
A cooling method, wherein the refrigerant discharged from the outer peripheral end of the gap is discharged to the outside of the case through a discharge port provided in the case. The cooling method according to claim 11 , comprising:
The cooling method, wherein the amount of refrigerant injected from the inlet is an amount that does not fill the inside of the case with the refrigerant. The cooling method according to claim 11 , comprising:
A cooling method, wherein the amount of refrigerant injected from the inlet is an amount that does not fill the gap with the refrigerant. A axial type motor according to claim 1, any one of 10,
The stator is disposed in a slot space between the teeth and has a connection member that covers the upper surface of the slot space,
The connecting member is provided with one or more guide openings for guiding a part of the refrigerant carried to the outer peripheral side end portion of the gap in the coil direction as the rotor rotates. Type motor. The axial type motor according to claim 14 ,
The axial type motor is characterized in that the guide opening is a through hole inclined in a predetermined direction with respect to a rotation axis. An axial type motor according to claim 14 or 15 ,
The axial type motor is characterized in that the guide opening is a long hole. The cooling method according to any one of claims 11 to 13 , further comprising:
The cooling of the coil is performed by guiding a part of the refrigerant conveyed to the outer peripheral side end of the gap in the coil direction through one or more guide openings formed in a part of the stator as the rotor rotates. A cooling method characterized by also performing.

Images