JP5097743B2 - Electric motor - Google Patents

Description

  The present invention relates to an electric motor.

2. Description of the Related Art Conventionally, there has been known a permanent magnet electric motor that includes a rotor that is rotatably supported around an axis and has a permanent magnet disposed thereon, and a stator that is disposed to face the periphery of the rotor and is wound with a coil. It has been. Here, as a configuration of the rotor, a configuration in which a permanent magnet is embedded in a rotor yoke on which magnetic plate materials are laminated is known. A rotor having such a configuration is known in which through holes (thickening holes) are formed in the rotor yoke for the purpose of reducing the weight of the rotor, and end plates are provided on both axial end surfaces of the rotor (for example, , See Patent Document 1).
In the electric motor of Patent Document 1, an opening (discharge port) is also formed in the end face plate so that a part of the through hole of the rotor yoke is exposed, and cooling oil or the like supplied into the through hole of the rotor yoke is discharged. It is configured to be able to.

JP 2009-27862 A

  By the way, in the electric motor of the above-mentioned patent document 1, the path | route which discharge | emits reliably the cooling oil etc. which were supplied in the through-hole of a rotor yoke is not ensured, but the problem that oil etc. stay in a through-hole has the problem. is there.

  Accordingly, the present invention has been made in view of the above circumstances, and provides an electric motor capable of improving the flow of oil and improving the cooling efficiency.

In order to solve the above problems, the invention described in claim 1 is an annular outer yoke portion (for example, the embodiment) in which a plurality of permanent magnets (for example, the permanent magnet 58 in the embodiment) is provided in the circumferential direction. An outer yoke portion 71), an annular inner yoke portion (for example, the inner yoke portion 72 in the embodiment) disposed inside the outer yoke portion, and an inner peripheral surface (for example, the embodiment) of the outer yoke portion. A rotor (for example, the embodiment) having a rib (for example, the rib 73 in the embodiment) that connects between the inner peripheral surface 71a of the inner yoke portion and the outer peripheral surface of the inner yoke portion (for example, the outer peripheral surface 72a in the embodiment). Rotor 22) and windings (for example, the coil 20 in the embodiment), and a stator (for example, an implementation) arranged so as to surround the outer peripheral surface of the rotor. In the electric motor (for example, the motor 23 in the embodiment) including the stator 21) in the state and a housing (for example, the motor housing 11 in the embodiment) that houses the rotor and the stator together with oil for cooling. A groove portion (for example, the groove portion 85 in the embodiment) is formed on the inner peripheral surface of the yoke from one end portion in the axial direction to the other end portion, and the bottom portion of the groove portion (for example, the bottom portion 85a in the embodiment ) is formed on the rotor. It is characterized by inclining radially outward from the axial center to both ends .

  The invention described in claim 2 is characterized in that the groove is formed on a line connecting between the axial center of the rotor (for example, the axial center B in the embodiment) and the permanent magnet.

  According to a third aspect of the present invention, in the rotor in which the permanent magnets having different polarities are alternately arranged, the groove portion includes a circumferential central portion of the permanent magnet and a rotation direction of the permanent magnet when the vehicle moves backward. It is characterized in that it is formed at a position corresponding to an intermediate portion between the end portion in the circumferential direction.

  According to a fourth aspect of the present invention, in the rotor in which the permanent magnets having the same polarity are arranged, the groove portion is formed on a line connecting between the axial center and a circumferential central portion of the permanent magnet. It is characterized by.

According to the fifth aspect of the present invention, end plates (for example, end plate 90 in the embodiment) are provided on both end surfaces in the axial direction of the rotor (for example, end surfaces 56a and 56b in the embodiment). (For example, the lightening hole 91 in the embodiment) is formed so as to expose the groove portion.

According to the first aspect of the present invention, a through hole is formed in the rotor by the inner peripheral surface of the outer yoke portion of the rotor, the outer peripheral surface of the inner yoke portion, and the adjacent rib, and the outer side is located radially outside the through hole. Since the groove portion is formed on the inner peripheral surface of the yoke portion, the cooling oil supplied into the through hole is smoothly guided into the groove portion by centrifugal force. Therefore, the oil can be guided from the groove portion and smoothly discharged from the through hole of the rotor, and the oil can be prevented from staying in the through hole. That is, the oil flowability can be improved and the cooling efficiency of the motor can be improved.
In addition, by inclining the bottom of the groove portion radially outward from the central portion in the axial direction of the rotor toward both ends, the oil guided into the groove portion is reliably discharged from the through hole of the rotor by centrifugal force. Can be more reliably suppressed from staying in the through hole. That is, the oil flowability can be further improved.

  According to the invention described in claim 2, the permanent magnet can be cooled by the oil flowing through the groove. Therefore, the cooling efficiency of the electric motor can be further improved.

  According to the third aspect of the present invention, in the rotor in which the permanent magnets having different polarities are alternately arranged, the groove portion is formed in the region where the magnetic flux density of the magnetic flux generated when the electric motor is driven is lowered. Therefore, the oil flow can be improved.

  According to the fourth aspect of the present invention, in the rotor in which permanent magnets having the same polarity are arranged, the groove is formed in the region where the magnetic flux density of the magnetic flux generated when driving the electric motor is low, so that the magnetic characteristics are not deteriorated. , Oil permeability can be improved.

According to the invention described in claim 5 , by providing the end face plates formed with the hollow holes so as to expose the groove portions on both end faces in the axial direction of the rotor, the weight of the end face plate can be reduced, and the rotor It is possible to prevent the permanent magnet from falling off the rotor during rotation. Further, the oil guided to the groove portion of the rotor is smoothly discharged from the both axial end surfaces of the rotor through the hole in the end face plate. Therefore, the oil flowability can be improved and the cooling efficiency of the motor can be improved.

It is a schematic structure sectional view of a power train in an embodiment of the present invention. It is a front view of the rotor in 1st embodiment of this invention. It is the A section enlarged view of FIG. It is a fragmentary sectional view explaining the shape of the axial direction of the groove part in the embodiment of the present invention. It is explanatory drawing (advance angle 0deg) which shows the magnetic flux density in 1st embodiment of this invention. It is explanatory drawing (advance angle 36deg) which shows the magnetic flux density in 1st embodiment of this invention. It is explanatory drawing (advance angle 72deg) which shows the magnetic flux density in 1st embodiment of this invention. It is a front view which shows the state which attached the end surface board to the rotor in 1st embodiment of this invention. It is a front view of the rotor in 2nd embodiment of this invention. It is explanatory drawing (advance angle 0deg) which shows the magnetic flux density in 2nd embodiment of this invention. It is explanatory drawing (advance angle 45deg) which shows the magnetic flux density in 2nd embodiment of this invention. It is explanatory drawing (advance angle 90deg) which shows the magnetic flux density in 2nd embodiment of this invention.

(First embodiment)
Next, a first embodiment of the present invention will be described with reference to FIGS. In the present embodiment, a motor employed in a vehicle powertrain will be described.
FIG. 1 is a schematic sectional view of a power train for a vehicle. As shown in FIG. 1, a vehicle power train (hereinafter referred to as a power train) 10 is fastened to a motor housing 11 that houses a motor 23 having a stator 21 and a rotor 22, and one side of the motor housing 11. A transmission housing 12 that houses a power transmission unit (not shown) that transmits power from the output shaft 24 of the motor 23, and a sensor housing 13 that is fastened to the other side of the motor housing 11 and houses the rotation sensor 25 of the motor 23. It is equipped with. The mission housing 12 includes a common housing 12A fastened to the motor housing 11 and a gear housing 12B fastened to the common housing 12A. The motor housing 11 is configured as a motor chamber 36, the mission housing 12 is configured as a mission chamber 37, and the sensor housing 13 is configured as a sensor chamber 38.

  The motor housing 11 is formed in a substantially cylindrical shape so as to cover the entire motor 23. A bearing 26 that rotatably supports one end of the output shaft 24 of the motor 23 is provided on the mission housing 12 side of the boundary between the motor housing 11 and the mission housing 12, and the boundary between the motor housing 11 and the sensor housing 13. On the sensor housing 13 side, a bearing 27 that rotatably supports the other end of the output shaft 24 of the motor 23 is provided.

  Further, a breather passage 35 communicating with each other is formed in the wall portion 31 of the motor housing 11, the wall portion 32 of the transmission housing 12, and the wall portion 33 of the sensor housing 13.

  Further, a water jacket 40 for cooling the motor 23 is provided in the wall portion 31 of the motor housing 11 so as to cover the entire circumference of the stator 21 of the motor 23. The stator 21 is shrink-fitted into the motor housing 11 and is disposed so as to be in close contact with the inner peripheral surface of the motor housing 11.

  A breather chamber 51 for separating the lubricating oil used in the powertrain 10 is formed in the mission housing 12. That is, the lubricating oil scattered by the rotation of the power transmission unit (gear) and the motor 23 can be separated in the breather chamber 51, and the lubricating oil leaks to the outside from the breather pipe 39 provided in the breather chamber 51 and communicating with the outside. This can be prevented.

  The breather chamber 51 is formed at a position corresponding to the uppermost portion of the power train 10. The breather chamber 51 communicates with the breather passage 35 so that high-pressure and high-temperature air in the power train 10 can be discharged from the breather pipe 39. Further, the breather chamber 51 communicates with the motor chamber 36, the mission chamber 37, and the sensor chamber 38 via the breather passage 35.

  The power train 10 is provided with an oil supply mechanism (not shown) that supplies oil to the bearings 26 and 27, the coil 20, the stator 21, and the like. The lubrication performance of the bearings 26 and 27 can be improved by supplying oil to the bearings 26 and 27, and the coil 20 and the stator 21 can be cooled by supplying oil to the coil 20 and the stator 21.

  Here, the configuration of the rotor 22 will be described with reference to FIGS. 2 and 3. FIG. 2 is a front view of the rotor, and FIG. 3 is an enlarged view of part A of FIG. As shown in FIGS. 2 and 3, the rotor 22 includes an annular outer yoke portion 71 in which a plurality of permanent magnets 58 are arranged in the circumferential direction, and an annular inner portion arranged inside the outer yoke portion 71. The yoke portion 72 has a plurality of ribs 73 (eight in this embodiment) that connect between the inner peripheral surface 71a of the outer yoke portion 71 and the outer peripheral surface 72a of the inner yoke portion 72.

  Specifically, the outer yoke portion 71, the inner yoke portion 72, and the rib 73 are formed on a single magnetic plate material 55, and a plurality of the magnetic plate materials 55 are stacked to constitute the rotor yoke 56. The permanent magnet 58 is held in an opening 57 formed in the outer yoke portion 71. Furthermore, the opening part 63 is formed in the inner peripheral side of the inner side yoke part 72, the output shaft 24 is penetrated by the opening part 63, and the rotor 22 is supported rotatably. The rotor 22 is disposed opposite to the stator 21 around which the coil 20 is wound with a predetermined interval. In the present embodiment, the permanent magnets 58 having different polarities are alternately arranged in the circumferential direction. Further, the rib 41 is formed on the rotor core 56 so as to divide the opening 57 in which the permanent magnet 58 is arranged, and the permanent magnet 58 is also divided into two and arranged in each opening. By doing so, the strength of the rotor core 56 can be improved.

  Here, a space surrounded by the inner peripheral surface 71 a of the outer yoke portion 71, the outer peripheral surface 72 a of the inner yoke portion 72, and the adjacent ribs 73, 73 is configured as the lightening hole 59. The same number of the lightening holes 59 as that of the permanent magnets 58 (eight in this embodiment) are formed, and all the lightening holes 59 are formed in substantially the same shape.

  The cutout hole 59 corresponds to a part of the inner peripheral surface 71 a of the outer yoke portion 71, and an arc portion 65 formed on the same radius of the rotor core 56 and a first straight line extending from both ends of the arc portion 65. Part 66 and a second straight part 67. The first straight portion 66 and the second straight portion 67 extend from the arc portion 65 toward the radially inner side of the rotor core 56, and intersect at an intersection 69 that is located on the outer peripheral surface 72 a of the inner yoke portion 72. . Intersections 69 of the plurality of lightening holes 59 are located on the same radius of the rotor core 56.

  The rib 73 formed between the adjacent cutout holes 59 is formed linearly between the radially outer outer end 81 and the radially inner inner end 82 of the rotor core 56. That is, the rib 73 is formed between the first straight portion 66 of the lightening hole 59 and the second straight portion 67 of the adjacent lightening hole 59.

  Here, the outer end portion 81 of the rib 73 includes an axial center B on the inner peripheral surface 71a of the outer yoke portion 71 and a substantially central portion of the adjacent permanent magnets 58 and 58 (substantially central portion of the openings 57 and 57). The inner end 82 of the rib 73 is located on the line segment 76 that connects the axial center B of the outer peripheral surface 72a of the inner yoke 72 and the adjacent permanent magnets 58 and 58 (openings 57 and 57). It is arranged on the inner side in the radial direction of the rotor core 56 within the range of the line segment connecting the position where either one is arranged. That is, the rib 73 is formed to be inclined with respect to the radial direction of the rotor core 56. In addition, the inclination direction of the rib 73 is configured to coincide with the rotation direction F of the motor 23 when the vehicle moves forward. Specifically, the direction from the outer end 81 to the inner end 82 of the rib 73 is formed so as to be along the rotational direction F of the rotor core 56 when the vehicle moves forward.

  Further, the arc portion 65 is formed with a groove portion 85 protruding outward in the radial direction. The groove portion 85 is formed in all the hollow holes 59 and is formed from the one axial end surface 56a of the rotor core 56 toward the other end surface 56b (see FIG. 1). As shown in FIG. 4, the bottom 85 a of the groove 85 is inclined radially outward from the axial center C of the rotor core 56 toward both end faces 56 a and 56 b.

  In the present embodiment, as shown in FIG. 3, the groove 85 includes a radial line segment 75 configured to divide the permanent magnet 58 into two equal parts, the axial center B of the rotor core 56, and the outer side of the rib 73. It is formed at the substantially central portion in the circumferential direction of the arc portion 65 surrounded by the line segment 76 connecting the end portion 81. In other words, the groove portion 85 is formed at a position corresponding to an intermediate portion between the circumferential central portion of the permanent magnet 58 and the circumferential end portion of the permanent magnet 58 near the rotational direction when the vehicle moves backward. All the groove portions 85 are formed at the same position with respect to the lightening hole 59.

  By forming the groove 85 at the above-described position, the magnetic characteristics are not deteriorated. Specifically, as shown in FIGS. 5 to 7, in the case of advance angles 0 deg, 36 deg, and 72 deg, the magnetic flux density in the region where the groove 85 is formed (the region surrounded by the broken line D) is low. Even if the groove portion 85 is formed, the influence on the magnetic characteristics of the motor 23 is small. Therefore, the magnetic characteristics of the motor 23 are not deteriorated. 5-7, the line segment described in the stator 21 and the rotor 22 becomes a magnetic flux line, and a location with few line segments becomes a location with a low magnetic flux density.

  Further, as shown in FIG. 8, end face plates 90 are provided on both end faces 56 a and 56 b in the axial direction of the rotor 22. The end face plate 90 is a plate-like member whose outer shape is formed in substantially the same shape as the rotor core 56, and can prevent the permanent magnet 58 from falling off the rotor 22. The end face plate 90 is formed with a plurality of lightening holes 91 to reduce the weight of the end face plate 90. In the present embodiment, eight hollow holes 91 having a substantially circular shape when viewed from the front are formed at substantially equal intervals along the circumferential direction. Further, the lightening hole 91 is formed at a position where the groove 85 of the rotor core 56 is exposed when viewed from the axial direction.

  According to the present embodiment, the inner peripheral surface 71 a of the outer yoke portion 71 of the rotor 22, the outer peripheral surface 72 a of the inner yoke portion 72, and the adjacent ribs 73, 61 form the thin hole 59 in the rotor 22. Since the groove portion 85 is formed on the inner peripheral surface 71a of the outer yoke portion 71 located on the radially outer side, the cooling oil supplied into the lightening hole 59 is smoothly guided into the groove portion 85 by centrifugal force. Therefore, the oil is guided to the groove portion 85 and is smoothly discharged from the inside of the lightening hole 59 of the rotor 22, and the oil can be prevented from staying in the lightening hole 59. That is, the oil flowability can be improved and the cooling efficiency of the motor 23 can be improved.

  Further, since the groove portion 85 is formed on a line connecting the axis center B of the rotor 22 and the permanent magnet 58, the permanent magnet 58 can be cooled with oil flowing through the groove portion 85. Therefore, the cooling efficiency of the motor 23 can be further improved.

  In addition, in the rotor 22 in which the permanent magnets 58 having different polarities are alternately arranged, the groove portion 85 is formed in a region where the magnetic flux density of the magnetic flux generated when the motor 23 is driven is low. Can be improved.

  Furthermore, by inclining the bottom 85a of the groove 85 radially outward from the axial center C of the rotor 22 toward both end faces 56a and 56b, the oil guided into the groove 85 is reliably ensured by the centrifugal force. It is possible to more reliably prevent oil from being discharged from the inside of the meat hole 59 and staying in the meat hole 59. That is, the oil flowability can be further improved.

  Then, by providing the end face plate 90 in which the hollow hole 91 is formed so as to expose the groove 85 on both axial end faces 56a and 56b of the rotor 22, the end face plate 90 can be reduced in weight and the rotor 22 can be reduced. It is possible to prevent the permanent magnet 58 from falling off the rotor 22 during the rotation. Further, the oil guided to the groove 85 of the rotor 22 is smoothly discharged from the axially opposite end faces 56 a and 56 b of the rotor 22 through the through holes 91 of the end face plate 90. Therefore, the oil flowability can be improved and the cooling efficiency of the motor 23 can be improved.

(Second embodiment)
Next, a second embodiment of the present invention will be described with reference to FIGS. The present embodiment is different from the first embodiment only in the arrangement configuration of the permanent magnets and the formation positions of the grooves, and the other configurations are substantially the same as those in the first embodiment. Detailed description will be omitted.
As shown in FIG. 9, the rotor 122 includes an annular outer yoke portion 71 in which a plurality of permanent magnets 58 are arranged in the circumferential direction, and an annular inner yoke portion 72 arranged inside the outer yoke portion 71. And a rib 73 that connects between the inner peripheral surface 71 a of the outer yoke portion 71 and the outer peripheral surface 72 a of the inner yoke portion 72. In the present embodiment, permanent magnets 58 having the same polarity are arranged.

  The arc portion 65 is formed with a groove portion 185 protruding outward in the radial direction. The groove portion 185 is formed in all the hollow holes 59, and is formed from the one axial end surface 56a of the rotor core 56 toward the other end surface 56b. Further, the bottom portion 185a of the groove portion 185 is inclined radially outward from the axial center portion C of the rotor core 56 toward both end surfaces 56a, 56b.

  In the present embodiment, the groove portion 185 is formed at the intersection of a radial line segment 75 configured to divide the permanent magnet 58 into two equal parts from the axial center B and the arc portion 65. All the groove portions 185 are formed at the same position with respect to the lightening hole 59.

  By forming the groove 185 at the above-described position, the magnetic characteristics are not deteriorated. Specifically, as shown in FIGS. 10 to 12, in the case of advance angles 0 deg, 45 deg, and 90 deg, the magnetic flux density in the region where the groove 185 is formed (the region surrounded by the broken line E) is low. Even if the groove portion 185 is formed, the influence on the magnetic characteristics of the motor is small. Therefore, the magnetic characteristics of the motor 23 are not deteriorated.

  According to the present embodiment, in the rotor 22 in which the permanent magnets 58 having the same polarity are arranged, the groove portion 185 is formed in the region where the magnetic flux density of the magnetic flux generated when the motor 23 is driven is low. The flowability of can be improved.

The present invention is not limited to the above-described embodiment, and includes various modifications made to the above-described embodiment without departing from the spirit of the present invention. That is, the specific structure and shape described in the embodiment are merely examples, and can be changed as appropriate.
For example, in the present embodiment, the configuration has been described in which eight permanent magnets are arranged, but the number of permanent magnets may be changed.

  DESCRIPTION OF SYMBOLS 11 ... Motor housing (housing) 20 ... Coil (winding) 21 ... Stator 22 ... Rotor 23 ... Motor (electric motor) 56 ... Rotor core 56a ... One end surface (end surface) 56b ... Other end surface (end surface) 58 ... Permanent magnet 61 ... Rib 71 ... Outer yoke portion 71a ... Inner peripheral surface 72 ... Inner yoke portion 72a ... Outer peripheral surface 85 ... Groove portion 85a ... Bottom portion 90 ... End face plate 91 ... Meat hole B ... Center of axis

Claims (5)

An annular outer yoke portion provided with a plurality of permanent magnets in the circumferential direction, an annular inner yoke portion disposed inside the outer yoke portion, an inner peripheral surface of the outer yoke portion, and the inner yoke portion A rotor having a rib connecting the outer peripheral surface of the rotor,
A stator provided with windings and disposed so as to surround the outer peripheral surface of the rotor;
A housing that houses the rotor and the stator together with oil for cooling,
A groove is formed on the inner peripheral surface of the outer yoke from one end to the other end in the axial direction .
The electric motor according to claim 1, wherein a bottom portion of the groove portion is inclined radially outward from a central portion in the axial direction of the rotor toward both end portions .   2. The electric motor according to claim 1, wherein the groove is formed on a line connecting between the axial center of the rotor and the permanent magnet.   In the rotor in which the permanent magnets having different polarities are alternately arranged, the groove portion includes a circumferential central portion of the permanent magnet, and a circumferential end portion of the permanent magnet that is closer to a rotational direction when the vehicle moves backward. The electric motor according to claim 2, wherein the electric motor is formed at a position corresponding to the intermediate portion.   3. The rotor in which the permanent magnets having the same polarity are arranged, wherein the groove is formed on a line connecting between the axial center and a circumferential central portion of the permanent magnet. Electric motor. End plates are provided on both axial end faces of the rotor, the electric motor according to any one of claims 1 to 4, the lightening hole of the end surface plate is characterized in that it is formed so as to expose the groove.

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