JP2011109808A - Cooling structure of motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cooling structure of a motor for quickly dissipating heat without increasing a Joule heat or the like even when a stator is operated at high speed rotation, by molding a stator and by quickly dissipating heat and efficiently cooling the stator. <P>SOLUTION: The cooling structure of the motor includes: a case 5 covering an inside of the motor formed with a molded stator 3 and a rotor 2 which pairs with the stator 3; and a cover 7 fitted with the case 5. The cooling structure of a motor interposes a spring member being as a thermally conductive member 9 which is constituted to dissipate heat by that a contact area of the stator 3 is enlarged by a thermal expansion which occurs when the stator 3 is heated, and to separate the stator 3, the case 5 and the cover 7 when the stator 3 is not heated. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a motor cooling structure configured to release heat from a molded stator via a heat transfer member.

  The motor generates heat with inevitable loss due to energization of the coil, and when the temperature rises, the magnetic characteristics deteriorate. In particular, motors used in hybrid vehicles and electric vehicles are used in harsh environments where a large current is applied to obtain a large driving force, and driving and energy regeneration are repeated. It has become important. In addition, it is desirable that a motor used as a driving force source of a vehicle and a device related thereto be as small and light as possible in order to improve the in-vehicle performance.

  An apparatus developed against such a background is described in Patent Document 1. In the apparatus described in Patent Document 1, a coil end is molded with a resin, and a stretchable heat conductive member made of a thin thin wire-like aggregate made of metal is disposed in the gap between the mold end surface and the bracket. It is formed as follows. Therefore, in the invention described in Patent Document 1, heat transfer from the mold end surface to the bracket is good.

  Further, in Patent Document 2, in a rotating electrical machine, a stator and a porous body that contacts the stator and a refrigerant supply hole that supplies lubricating oil to the porous body are provided, and heat generated in the stator is generated by the lubricating oil through the porous body. Shaped to be removed. Therefore, in the invention described in Patent Document 2, the stator is cooled with a simple structure.

  And in patent document 3, the ventilation path by which cooling air is ventilated from the inner peripheral side of radial direction by rotation of a rotor is formed by the coil end group of a stator winding, and the teeth part of a stator core. . Since the cooling air flows through the narrow ventilation path, the cooling air speed is increased, and the heat generated in the stator winding is efficiently radiated to the cooling air, so that the temperature rise of the stator is suppressed. Therefore, in the invention described in Patent Document 3, an increase in the temperature of the stator can be suppressed, so that the output can be improved.

JP-A-8-223866 JP 2004-215353 A JP 2002-218687 A

  The apparatus described in Patent Document 1 described above does not consider the thermal expansion of the mold and has no urging force on the thin thin wire-like aggregate made of metal, so that a gap is formed between the cover and the mold. As a result, contact cannot be maintained, and as a result, problems such as inability to secure thermal conductivity may occur.

  The device described in Patent Document 2 described above includes a case for storing the stator, but this case has no cover, and only the case is provided with a porous body, an oil passage, and a coolant supply hole. . Therefore, the process and assembly at the time of manufacturing the case may be very difficult.

  Moreover, the apparatus described in Patent Document 3 performs cooling by a cooling fan and an exhaust hole. Therefore, since there is no structure for directly cooling the heat generation of the stator and the stator winding by cooling the heat generation of the stator and the stator winding only by the cooling air, the width and diameter of the teeth portion of the stator core There was a problem that cooling had to be achieved only by the ratio with the direction length.

  The present invention has been made paying attention to the technical problem described above, and is directly and quickly dissipated from a molded stator via a heat transfer member, and is operated at high speed. It is another object of the present invention to provide a motor cooling structure that can quickly dissipate heat without increasing Joule heat and the like and can be easily manufactured.

  In order to achieve the above object, the invention of claim 1 comprises a case that covers the interior of a motor formed by a molded stator, a rotor that is paired with the stator, and a cover that fits into the case. In the cooling structure of the motor, when the stator is heated, heat is dissipated by increasing the contact area due to thermal expansion, and when the stator is not heated, the stator is separated from the case and the cover. The motor cooling structure is characterized in that a spring member serving as a heat transfer member is interposed.

  The invention according to claim 2 is the motor cooling structure according to claim 1, wherein the spring member includes a wave spring or a disc spring.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, the disc spring is configured such that a large end surface side in the radial direction formed in a tapered shape contacts a mold member side formed in the stator. This is a cooling structure for a motor.

  According to a fourth aspect of the present invention, there is provided a motor cooling structure including a case that covers the interior of the motor formed by a molded stator, a rotor that is paired with the stator, and a cover that is fitted to the case. A spacer serving as a heat transfer member is provided between the mold member and the case so as to have a predetermined area that thermally expands at a predetermined temperature and comes into contact with the stator and the case or the cover. The motor cooling structure characterized by the above.

  According to a fifth aspect of the present invention, in any one of the first to fourth aspects of the present invention, an oil path is formed on the outer peripheral side of the coil end that constitutes the stator, and the mold member and the A cooling structure for a motor, characterized in that a lubricating oil is supplied from a gap between cases to cool the motor.

  A sixth aspect of the present invention is the motor cooling structure according to any one of the first to fourth aspects, wherein the heat transfer member is formed by insulating coating.

  The invention of claim 7 is the invention according to any one of claims 1 to 4, wherein an elastic material constituting an elastic member is disposed between the mold member and the cover, or the elastic material is used as the mold member or the cover. And a cooling structure for the motor.

  The invention according to claim 8 is the cover according to any one of claims 1 to 4, wherein the cover having a lower strength and higher thermal conductivity than the mold member is formed in two layers because the strength is lower than that of the mold member. The motor cooling structure is characterized in that this member is disposed between the two.

  According to the first aspect of the present invention, the heat transfer member is formed of a molded stator, the heat transfer member between the stator and the case and the cover, and the spring member interposed between the heat transfer member and the spring member and the cover. A sufficient contact area can be secured, and a close contact state is also possible.

  Here, according to the invention of claim 2, since the spring member includes a wave spring or a disc spring, it is possible to connect the stator and the case, and a close contact state is also possible.

  According to a third aspect of the present invention, the disc spring is configured such that a large end face side in the radial direction formed in a tapered shape is in contact with the mold member side, thereby contacting the stator and the mold member, respectively. Therefore, the cooling capacity can be ensured by increasing the contact area on the side of the mold member having a low thermal conductivity and reducing the thermal resistance.

  According to the invention of claim 4, since the reaction force by the spring is not applied at the time of assembly, the cover portion can be easily and reliably attached.

  Further, according to the invention of claim 5, in the high temperature region of the stator or the mold member, the gap is filled by thermal expansion, so that heat transfer is improved, and further, the leakage amount of the oil passage is reduced, so that the flow rate of the lubricating oil is increased. Therefore, the cooling capacity is further improved.

  According to the invention of claim 6, electrical insulation can be performed between the stator, the mold member, the cover and the like.

  Furthermore, according to the seventh aspect of the present invention, it is possible to absorb a gap that absorbs a part of the pressure generated when the elastic material is thermally expanded by the deformation of the elastic material, and to maintain a close contact surface.

  According to the invention of claim 8, since the member having a lower strength and higher thermal conductivity than the mold member is disposed between the covers, the heat transfer rate is improved. Moreover, the material which comprises this member can be selected freely.

It is sectional drawing which shows typically an example of the cooling structure of the motor which concerns on this invention. (A), (b) is sectional drawing and schematic block diagram which show an example of the oil path used with the cooling structure of the motor which concerns on this invention. It is sectional drawing which shows the other Example of this invention. It is sectional drawing which shows an example of the member used with the cooling structure of the other motor which concerns on this invention.

  The present invention will be described based on a specific example shown in the drawings. In the motor cooling structure 1 according to the present invention, a so-called rotor 2 that is a rotor core and a so-called stator 3 that is a stator core for the rotor 2 are disposed. The stator 3 is formed with a so-called coil 4 that is a stator winding. The motor cooling structure 1 is assembled by a case 5 serving as the outside thereof and a cover 7 fitted to the case 5 with, for example, bolts 6. The stator 3 is formed with a mold member 8 made of resin, for example. That is, it is constituted by a case 5 that covers the interior of the motor formed by the molded stator 3 and the rotor 2 that is paired with the stator 3, and a cover 7 that is fitted to the case 5.

  A heat transfer member 9 is formed between the mold member 8 formed on the stator 3 and the case 5 and the cover 7. For example, a wave spring 10 which is a spring member is disposed on the heat transfer member 9. The wave spring 10 is a metal spring and is configured as a heat transfer path (arrow 11) from the stator 3. Heat is released from the stator 3 (arrow 12) from this heat transfer path.

  The operation of the motor cooling structure 1 having the above configuration will be described. When the motor is operating, that is, the rotor 2 is rotating at a high speed. As the rotor 2 rotates at high speed, Joule heat is generated as current flows in the rotor 2 and the stator 3. This heat heats the stator 3 and the like. Therefore, it is necessary to release the heat accumulated in the stator 3. At this time, the heat accumulated in the stator 3 by the mold member 8 and the wave spring 10 is radiated by heat transfer.

  And as a substitute member of the wave spring 10 used as the said spring member, you may use a disc spring, for example. Since the disc spring is used at this time, for example, the radially outer surface side of the disc spring formed in a tapered shape is brought into contact with the mold member 8. Then, by contacting the radially inner diameter surface side of the disc spring to the case 5, the contact area on the mold member 8 side having a small thermal conductivity is increased, and the thermal resistance is further reduced, thereby further improving the cooling capacity.

  Further, in the case of the motor cooling structure 1 in which a spacer (so-called shim) (not shown) is arranged between the mold member 8 and the case 5 as an alternative member of the spring member, when the stator 3 reaches a predetermined temperature, the mold member Since the area of contact with the spacer is increased due to thermal expansion, the heat transfer effect is enhanced. At this time, the case 5 and the cover 7 can be easily assembled. When the stator 3 does not need to be cooled, that is, when the motor is not operating, the spacer does not contact both of the mold member 8 and the case 5, so that vibration transmitted from the cover 7 is not transmitted, for example. Therefore, the durability of the mold member 8 is improved.

  2A and 2B are a cross-sectional view and a schematic configuration diagram showing an example of an oil passage used in still another motor cooling structure according to the present invention. In FIG. 2A, an oil passage 13 is formed. The oil passage 13 is formed between the mold member 8 and the case 5 and the cover 7. The lubricating oil stored in the oil pan 14 is caused to flow to the normal drain 16 by the oil pump 15 as shown in FIG. At this time, the lubricating oil flows so as to be branched from the normal drain 16 by the oil passage 13 formed between the mold member 8 and the case 5 and the cover 7.

  The operation at this time will be described. For example, when the stator 3 is at an extremely high temperature, the gap between the oil passage 17 of the lubricating oil formed between the mold member 8 and the case 5 and the cover 7 is closed to thereby close the normal oil passage. The flow rate of the lubricating oil flowing through the cylinder increases and the cooling capacity improves. At this time, the cooling capacity of the lubricating oil is proportional to the flow rate. And at the time of high temperature, by flowing lubricating oil through the gap formed between the mold member 8 and the case 5 and the cover 7, the cooling capacity is improved by eliminating the heat insulating layer (air) and reducing the pipe resistance. Loss reduction is possible.

  When the heat transfer member 9 is an insulating coating, electrical insulation can be performed between the stator 3 or the mold member 8 and the case 5 and the cover 7.

  Here, as shown in FIG. 3, an elastic material 18 is disposed between the mold member 8 and the cover 7 instead of the spring member and the spacer. Alternatively, the elastic material 18 is disposed so as to be integrated with the mold member 8 or the cover 7. Further, the elastic member 18 may be used in combination with the spring member or the spacer. When the elastic material 18 is heated, a deformation relief shape 19 of the elastic material 18 is formed which is a gap that absorbs a part of the elastic material 18 that becomes a pressure generated when the elastic material 18 is thermally expanded.

  The operation will be described. Since the thermally expanded portion of the elastic material 18 is absorbed by the deformation relief shape 19, the contact surface between the mold member 8 and the cover 7 can be enlarged. Therefore, the heat dissipation effect transmitted from the elastic material 18 to the cover 7 is improved.

  Further, as shown in FIG. 4, the cover 7 formed in two layers because the member 20 (part surrounded by a broken line) having lower strength than the mold member 8 and higher thermal conductivity is lower in strength than the mold member 8. , 21, the member 20 is arranged. Since the member 20 has, for example, a metal string shape, the member 20 is formed so as to be sandwiched between the covers 7 and 21 formed in two layers.

  The operation will be described. First, the heat transmitted from the mold member 8 is absorbed by the cover 21 which is the first layer, and the heat is transmitted to the member 20. Then, the heat transmitted to the member 20 is transmitted to the cover 7 serving as the second layer and radiated. Therefore, the adhesion of the member 20 and the absorption of heat due to linear expansion are compatible. In addition, as the material of the member 20, a material having high thermal conductivity can be freely selected and used.

  DESCRIPTION OF SYMBOLS 1 ... Motor cooling structure, 2 ... Rotor, 3 ... Stator, 4 ... Coil, 5 ... Case, 6 ... Bolt, 7 ... Cover, 8 ... Mold member, 9 ... Heat transfer member, 10 ... Wave spring, 11 ... Arrow , 12 ... arrow, 13 ... oil passage, 14 ... oil pan, 15 ... oil pump, 16 ... normal drain, 17 ... oil passage for lubricating oil, 18 ... elastic material, 19 ... deformed relief shape, 20 ... member, 21 ... Cover.

Claims (8)

In the cooling structure of the motor constituted by a case that covers the inside of the motor formed by a molded stator and a rotor that is paired with the stator, and a cover that fits into the case,
When the stator is heated, heat is dissipated by increasing the contact area due to thermal expansion. When the stator is not heated, the spring becomes a heat transfer member configured to separate the stator from the case and the cover. A motor cooling structure characterized in that a member is interposed.   The motor cooling structure according to claim 1, wherein the spring member includes a wave spring or a disc spring.   3. The motor cooling according to claim 1, wherein the disc spring is configured such that a large end face side in a radial direction formed in a tapered shape contacts a mold member side formed in the stator. 4. Construction. In the cooling structure of the motor constituted by a case that covers the inside of the motor formed by a molded stator and a rotor that is paired with the stator, and a cover that fits into the case,
A spacer serving as a heat transfer member configured to have a predetermined area that thermally expands at a predetermined temperature between the mold member and the case in the stator and contacts the stator and the case or the cover; A motor cooling structure characterized by being arranged.   An oil passage is formed on an outer peripheral side of a coil end constituting the stator, and the oil passage is cooled by supplying lubricating oil from a gap between the mold member and the case in a predetermined temperature range. The motor cooling structure according to any one of 1 to 4.   5. The motor cooling structure according to claim 1, wherein the heat transfer member is formed of an insulating film.   The elastic material which comprises an elastic member is arrange | positioned between the said mold member and the said cover, or this elastic material is integrally formed with the said mold member or the said cover. The motor cooling structure described in 1.   5. A member having lower strength than the mold member and high thermal conductivity is disposed between the covers formed in two layers because the member has lower strength than the mold member. The motor cooling structure according to any one of the above.

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