JP2013165542A - Lubrication structure for rotating electric machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lubrication structure for a rotating electric machine that can suppress surface damage in a fitting portion between a rotor shaft and a bearing and can enhance lubrication and cooling performance of the bearing by increasing a flow rate of a lubricant.SOLUTION: A lubrication structure for a rotating electric machine is fitted to the rotating electric machine including a rotor which has a rotor shaft 32 with an oil passage 33 formed at an axial center and rotates about the axial line of the rotor shaft 32 and a bearing 41 which supports the rotor shaft 32, and can feed a lubricant to the bearing 41 through the oil passage 33. A groove-shaped notch 34 which opens on an end face 32b of the rotor shaft 32 and extends from the oil passage 33 toward an outer peripheral face 32c side of the rotor shaft 32 is formed at one end 32a on the bearing 41 side of the rotor shaft 32. A bottom 34b of the notch 34 is located at least within an arrangement region Lx of the bearing 41 in the axial direction of the rotor shaft 32 on the outer peripheral face 32c of the rotor shaft 32.

Description

  The present invention relates to a lubrication structure for a rotary machine, and more particularly to a lubrication structure for a rotary machine suitable for a vehicle power transmission device such as a hybrid transaxle by a shaft center cooling system having an oil passage in a shaft center portion of a rotor.

  A shaft-cooled rotary machine with a cooling oil passage in the rotor shaft center is widely used, but rotation with a lubrication structure in which the lubricating oil that passes through the cooling oil passage is used for lubrication and cooling of bearings, etc. Machines are frequently used in power transmission devices for vehicles, for example. Further, in a vehicle power transmission device such as a hybrid transaxle that uses an internal combustion engine and an electric motor (the electric motor here may be an electric motor and a generator or a generator motor), a large number of rotating elements are included in the case. Since it is mounted at a high density and the amount of heat transferred from an electric motor or a generator is increased, a lubricating structure excellent in bearing lubrication and cooling performance is required even in a cooling oil passage having a small cross-sectional area.

  As a lubrication structure of such a rotary machine, for example, by increasing the diameter of an oil passage extending in the axial direction of the rotor shaft toward the downstream side in the vicinity of the bearing portion, the flow of the lubricating oil in the oil passage can be reduced. There is known one that is promoted by urging the inner circumferential wall surface of the oil passage by centrifugal force (for example, see Patent Document 1).

  Further, the output shaft and the input shaft are connected by the connecting member on which the motor rotor is mounted, and a part of the oil supplied from the upper part of the motor housing is caused to flow into the spline connecting portion between the input shaft and the connecting member. There is known one in which lubricating oil can be supplied to the bearing side of the output shaft through an oil passage between the output member and the output member (for example, see Patent Document 2).

  Further, an oil passage is opened in the bearing support bracket for housing the bearing, and the bearing support bracket is cooled by an air flow passing through the labyrinth packing and flowing into the bearing side (for example, see Patent Document 3), a bearing box A refrigerant chamber is formed inside, and a hole extending in the axial direction is formed in the shaft end portion of the rotor core supported by the bearing so that the vicinity of the bearing is cooled by the refrigerant (for example, see Patent Document 4). It has been.

JP 2006-300101 A JP 2009-071905 A JP 2008-061468 A JP 2007-336646 A

  However, in the conventional rotating machine lubrication structure as described above, the engagement state between the inner ring (inner race) of the bearing that supports the end of the rotor shaft and the rotor shaft is relatively loose. There are many cases where even a relatively tight fitting state results in a relatively loose fitting state due to temperature changes. Therefore, surface damage such as so-called fretting wear, where the inner race surface of the inner race and the outer circumference surface of the rotor shaft are in contact with each other and repeatedly wear and slide down at the fitting portion between the inner race and the rotor shaft of the bearing. There was a problem that it was likely to occur.

  In addition, when the shaft end of another rotating element is inserted into the axial center of the rotor shaft and the cooling oil passage becomes narrow, or when the cooling oil passage cross-sectional area has to be reduced due to bearing size limitations, There is a problem that the lubrication and cooling performance of the bearing cannot be sufficiently obtained because the flow rate of the lubricating oil passing through the cooling oil passage cannot be sufficiently secured.

  Therefore, the present invention provides a lubrication structure for a rotating machine that can suppress surface damage such as fretting wear at a fitting portion between a rotor shaft and a bearing and increase the lubrication oil flow rate and increase the lubrication and cooling performance of the bearing. To do.

  In order to solve the above problems, a lubricating structure for a rotating machine according to the present invention includes: (1) a rotor shaft having an oil passage formed in an axial center thereof, the rotor rotating about the axis of the rotor shaft, And a bearing for supporting the rotor shaft, and a lubricating structure for a rotating machine capable of supplying lubricating oil to the bearing through the oil passage, and one end of the rotor shaft on the bearing side A concave notch surface that opens on the end surface of the one end portion and extends from the oil passage toward the outer peripheral surface side of the rotor shaft, and the bottom of the notch surface is at least on the outer peripheral surface of the rotor shaft. It is located in the arrangement | positioning area | region of the said bearing in the axial direction of the said rotor axis | shaft.

  Accordingly, in the vicinity of the concave notch surface extending from the oil passage formed in the axial center portion of the rotor shaft toward the outer peripheral surface side of the rotor shaft, the lubricating oil is radiated outward by the centrifugal force when the rotor shaft rotates. By energizing and promoting the outflow of the lubricating oil at the downstream end of the oil passage, the flow of the lubricating oil flowing in the oil passage to the downstream side is sufficiently promoted, and the lubrication and cooling performance of the bearing is sufficiently enhanced. Enhanced. In addition, since the bottom of the notch surface is located at least on the outer peripheral surface of the rotor shaft and within the bearing arrangement region in the axial direction of the rotor shaft, the lubricating oil that has flowed out from the downstream end of the oil passage is removed from the bearing and the rotor. It becomes easy to permeate between the fitting surfaces with the shaft, and surface damage such as fretting wear at the fitting portion between the rotor shaft and the bearing is suppressed.

  In the lubricating structure for a rotary machine of the present invention, (2) at least one oil groove in which the notch surface extends from the oil passage to the radial direction of the rotor shaft at one end portion on the bearing side of the rotor shaft. It is desirable to form.

  Thereby, the flow direction of the lubricating oil flowing out from the downstream end of the oil passage can be directed radially outward by the oil groove. The direction of the oil groove is not limited to the radial direction, and may be inclined to the rear side in the rotational direction, or may be inclined and curved.

  In the lubricating structure for a rotary machine having the configuration of (2) above, (3) it is preferable that the oil groove has a certain depth in the axial direction of the rotor shaft. This is because the cross-sectional area of the oil groove can be easily made constant and the processing becomes easy. However, the groove depth of the oil groove can be changed according to the position in the radial direction.

  In the lubricating structure for a rotary machine according to the present invention, (4) the bottom portion of the notch surface is preferably orthogonal to the axial direction of the rotor shaft.

  In this case, the bottom of the notch surface is located within the bearing arrangement region in the axial direction over the entire area of the notch surface in the radial direction of the rotor shaft, and the urging force of the lubricating oil radially outward due to centrifugal force As a result, the lubricating oil can surely penetrate between the fitting surfaces of the bearing and the rotor shaft.

  In the lubricating structure for a rotary machine according to the present invention, (5) it is preferable that an end face of the one end portion is located outward from an arrangement region of the bearing in the axial direction of the rotor shaft.

  As a result, the lubricating oil flowing out from the downstream end of the oil passage can be reliably supplied to the end face side of the bearing in the axial direction of the rotor shaft, and the lubrication and cooling performance of the bearing can be improved.

  In the lubricating structure for a rotary machine according to the present invention, (6) a cylindrical support member that rotatably supports one end portion of the rotor shaft on the bearing side via the bearing is provided. It is preferable that a through hole is formed so as to extend from the inner space connected to the oil passage to the outer peripheral surface side.

  As a result, the flow in the radially outward direction of the lubricant flowing out from the downstream end of the oil passage causes the air in the vicinity of the lubricant to flow in the radially outward direction through the through hole, and the downstream end of the oil passage By reducing the air pressure in the vicinity, the outflow of the lubricating oil can be promoted. Further, even if foreign matter that easily induces seizure or wear is mixed in the vicinity of the bearing, the foreign matter can be discharged from the inner space through the through hole together with the lubricating oil, and the reliability can be improved.

  In the lubricating structure of a rotating machine having the configuration of (6) above, (7) the inner space of the cylindrical support member is closed on one side in the axial direction and the bearing on the other side in the axial direction. It may be blocked by one end of the side and the bearing.

  In this case, the air pressure in the vicinity of the downstream end of the oil passage can be reliably reduced, and the outflow of the lubricating oil from the oil passage can be further promoted.

  According to the present invention, the lubricating oil is urged radially outward by centrifugal force in the vicinity of the concave notch surface extending from the oil passage in the axial center portion of the rotor toward the outer peripheral surface side of the rotor shaft, The outflow of lubricating oil at the downstream end can be promoted. Furthermore, since the bottom of the notch surface is positioned in the bearing arrangement region in the axial direction on at least the outer peripheral surface of the rotor shaft, it facilitates the penetration of the lubricating oil between the fitting surfaces of the bearing and the rotor shaft. It is possible to provide a lubrication structure for a rotating machine that can suppress surface damage such as fretting wear in a fitting portion between a rotor shaft and a bearing and increase the lubrication oil flow rate and increase the lubrication and cooling performance of the bearing.

It is a schematic sectional drawing which shows the cooling structure of the electric motor of the hybrid transaxle for vehicles which concerns on 1st Embodiment of this invention. It is II-II arrow sectional drawing of FIG. It is a principal part expanded sectional view which shows the bearing vicinity of the rotor shaft of the electric motor of the hybrid transaxle for vehicles which concerns on 1st Embodiment of this invention. FIG. 4 is a sectional view taken along arrow IV-IV in FIG. 3. It is the principal part expanded sectional view which shows the cooling structure of the electric motor of the hybrid transaxle for vehicles which concerns on 2nd Embodiment of this invention.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
1 to 4 show a cooling structure for an electric motor of a hybrid transaxle for a vehicle according to a first embodiment of the present invention. The hybrid transaxle is integrally fastened to an engine (internal combustion engine) (not shown) to form a part of a transmission case, an input shaft connected to the output shaft of the engine, and left and right drive wheel shafts. A pair of output shafts (not shown) connected to each other is provided, and at least one electric motor is incorporated in the case, and a known power split mechanism and speed reduction mechanism are incorporated.

  That is, this hybrid transaxle includes, for example, a pair of planetary gear mechanisms that serve as a power split mechanism and a speed reduction mechanism, and a known transmission mechanism having a counter drive gear in an outer cylinder portion that integrates the ring gears, The first generator motor coupled to the input element on the power split mechanism side, the second generator motor coupled to the input element on the speed reduction mechanism side, the counter driven gear meshing with the counter drive gear, and the power from the counter driven gear to the differential ring gear And a differential mechanism for inputting and outputting the power to the left and right drive shafts. Since the structure of such a gear train itself is the same as a known one, here, a lubricating structure of an electric motor (rotary machine) employed in this transaxle will be described.

  An electric motor 10 shown in FIGS. 1 and 2 corresponds to the first generator motor or the second generator motor described above, for example, corresponds to a second generator motor mainly operated by a motor, and is housed in a case 11. Yes.

  The electric motor 10 includes a stator 12 around which a three-phase coil is wound, and an internal magnet type rotor 13 that can use reluctance torque. The stator 12 supplies AC power from an inverter (not shown). When the rotating magnetic field is received, the rotor 13 is rotated by the rotating magnetic field.

  The stator 12 is fastened to the case 11 by a plurality of fastening bolts (not shown). For example, a stator coil is formed on a substantially annular stator core 21 (consisting of a plurality of divided cores in the figure), which is formed by laminating a plurality of electromagnetic steel plates. 22 is wound.

  The rotor 13 is obtained by embedding a plurality of permanent magnets 31p in a substantially V shape at equal angular intervals in a rotor body 31 formed by laminating a plurality of electromagnetic steel plates, for example, and a rotor shaft 32 at the center of the rotor body 31. have. In addition, the whole structure of such an electric motor is the same as that of a well-known thing.

  The above-described differential ring gear, counter driven gear, and counter drive gear are configured to scoop up lubricating oil from the inner bottom side of the case 11 and store it in an oil catch tank (not shown), at least near the stator 12 from the catch tank. Lubricating oil (lubricating and cooling oil) can be supplied.

  The rotor shaft 32 of the rotor 13 is rotatably supported by the case 11 via a bearing 41, and has an oil passage 33 extending in the direction of the rotation center axis of the rotor 13 at the axial center. The oil passage 33 is composed of a straight hole having a circular cross section having the same diameter, for example. The bearing 41 has a plurality of rolling elements such as steel balls 41c interposed between the inner ring 41a and the outer ring 41b, for example.

  Lubricating oil is supplied to the oil passage 33 from the oil catch tank described above or from the oil pump 51 as shown in FIG. Here, the oil pump 51 receives the lubricating oil pumped up from the oil reservoir 15 which is an inner bottom portion of an oil pan (not shown) installed in the lowermost part of the transmission case including the case 11 or one of the chambers in the transmission case. In addition to being supplied to the power split mechanism and the speed reduction mechanism described above, the oil can be supplied into the oil passage 33. The oil pump 51 is, for example, an electric type and is controlled by an electronic control unit (not shown), but may be a mechanical oil pump. Alternatively, the lubricating oil may not be supplied from the oil pump 51 into the oil passage 33, and the lubricating oil may flow into the oil passage 33 only from the oil catch tank described above.

  The electric motor 10 thus has the rotor shaft 32 in which the oil passage 33 is formed in the shaft center portion, the rotor 13 that rotates around the axis of the rotor shaft 32, the bearing 41 that supports the rotor shaft 32, It is a rotating machine equipped with. The bearing 41 that supports the rotor shaft 32 of the electric motor 10 is fed with lubricating oil from the oil pump 51 (or oil catch tank) through the oil passage 33.

  As shown in FIGS. 3 and 4, a plurality of, for example, four groove-shaped notches 34 are radially formed at one end portion 32 a on the bearing 41 side of the rotor shaft 32 at equal angular intervals (in this case, 90 ° intervals). Is formed.

  An inner wall surface 34a (concave notch surface) of each notch 34 has a concave shape that opens outward (on the right side in FIGS. 1 and 3) on the end surface 32b of the one end 32a of the rotor shaft 32, and an oil passage. 33 extends radially outward from the outer circumferential surface 32 c of the rotor shaft 32.

  The bottom 34b of the inner wall surface 34a, which is the inner back surface of the notch 34, is located in the arrangement region Lx of the bearing 41 in the axial direction of the rotor shaft 32 at least on the outer peripheral surface 32c of the rotor shaft 32. 34 is a part of the depth direction (axial direction of the rotor shaft 32) and overlaps with the arrangement region Lx of the bearing 41.

  In addition, the inner wall surfaces 34a of the plurality of notches 34 are a plurality (at least one) extending in the radial direction of the rotor shaft 32 from the downstream end portion 33a of the oil passage 33 to the one end portion 32a of the rotor shaft 32 on the bearing 41 side. The oil groove has a notch 34 serving as an oil groove, and a constant groove depth Dg in the axial direction of the rotor shaft 32, a groove length Lg in the radial direction of the rotor shaft 32, and the rotor shaft 32. Has a groove width Wg in the tangential direction of the outer peripheral surface 32c.

  Further, the bottom 34b of the inner wall surface 34a of the notch 34 is orthogonal to the axial direction of the rotor shaft 32, and the notch 34 is located in the arrangement region Lx in the axial direction of the rotor shaft 32 over the entire length direction. Is located.

  Further, the end surface 32b of the one end portion 32a of the rotor shaft 32 is located outward (right side in FIG. 3) from the arrangement region Lx of the bearing 41 in the axial direction of the rotor shaft 32, and is a notch 34 as an oil groove. The outer end face 41e of the bearing 41 is located within the range of the groove depth Dg.

  Note that the groove depth Dg and the groove width Wg of the notch 34 as an oil groove are constant depth and width in FIG. 3, respectively, depending on the position of the rotor shaft 32 in the radial direction. May vary in depth or width.

  Further, the bottom 34 b of the inner wall surface 34 a of the notch 34 may deviate from the direction orthogonal to the axial direction of the rotor shaft 32. Further, the direction of the notch 34 as the oil groove is not necessarily limited to the radial direction, and may be inclined rearward in the rotational direction, or may be inclined and curved.

  Further, the notch 34 does not have to be located in the arrangement region Lx in the axial direction of the rotor shaft 32 over the entire length direction, and the arrangement region Lx only in the outer peripheral surface 32c of the rotor shaft 32 and the vicinity thereof. It may be located inside.

  On the other hand, the case 11 is provided with a cylindrical cylindrical support member 16 that rotatably supports one end portion 32 a of the rotor shaft 32 on the bearing 41 side via the bearing 41.

  The cylindrical support member 16 is formed with a through hole 16h that extends from the inner space 16a connected to the oil passage 33 to the outer peripheral surface 16b side.

  Here, the inner space 16a of the cylindrical support member 16 is closed by the case 11 on one side in the axial direction, and by the one end portion 32a on the bearing 41 side of the rotor shaft 32 and the bearing 41 on the other side in the axial direction. It is blocked. The cylindrical support member 16 may be configured by an end portion of a rotation shaft of another rotation element that is rotatably supported by the case 11.

  Next, the operation will be described.

  In the hybrid transaxle incorporating the electric motor 10 of the present embodiment configured as described above, at least one of the engine and the electric motor 10 operates as a prime mover, so that vehicle driving force is generated, or the first and first It operates as a generator of the electric motor 10 that is one of the two generator motors, and stores it in a battery (not shown).

  For example, at the time of starting and at a light load, if the required power is equal to or less than a specified value (varies depending on the state of charge), the electric motor 10 that is the second generator motor is set to the electric vehicle traveling mode in which it operates as a traveling drive motor. Then, cooperative control between the ECU for overall control of the hybrid transaxle and the engine ECU is executed. When the required power exceeds a specified value, the engine shifts to driving, but at the time of low speed and high load by driving the engine, the first generator motor operates as a generator and the second generator motor is for assist (power assist). It operates as a motor.

  In such an operating state of the hybrid transaxle, when the rotor 13 of the electric motor 10 rotates, the lubricating oil discharged from the oil pump 51 is supplied into the oil passage 33, the rotor 13 is cooled in the center, and the oil The bearing 41 is lubricated and cooled by the lubricating oil flowing out from the downstream end 33a of the passage 33.

  In this state, the lubricating oil is supplied to the rotor shaft 32 in the vicinity of the inner wall surface 34 a of the notch 34 extending from the oil passage 33 formed in the axial center portion of the rotor shaft 32 toward the outer peripheral surface 32 c of the rotor shaft 32. It is biased outward by the centrifugal force during rotation. Thus, the outflow of the lubricating oil at the downstream end 33a of the oil passage 33 is promoted, the flow of the lubricating oil flowing in the oil passage 33 to the downstream side is sufficiently promoted, and the outflow flow rate of the lubricating oil is ensured. As a result, the lubrication and cooling performance of the bearing 41 is sufficiently enhanced.

  Moreover, since the bottom 34b of the inner wall surface 34a of the notch 34 is located at least on the outer peripheral surface 32c of the rotor shaft 32 and within the arrangement region Lx of the bearing 41 in the axial direction of the rotor shaft 32, the downstream of the oil passage 33 Lubricating oil that has flowed out from the end portion 33a is likely to penetrate into a minute gap between the inner ring 41a of the bearing 41 and the outer peripheral surface 32c of the rotor shaft 32 (between the fitting surfaces). As a result, surface damage such as fretting wear at the fitting portion between the rotor shaft 32 and the bearing 41 is suppressed.

  In the present embodiment, the inner wall surface 34 a of the notch 34 forms at least one oil groove extending from the oil passage 33 in the radially outward direction of the rotor shaft 32 in the one end portion 32 a on the bearing 41 side of the rotor shaft 32. Therefore, the flow direction of the lubricating oil flowing out from the downstream end portion of the oil passage 33 can be surely directed to the radial outward direction by the oil groove.

  Further, since each notch 34 as an oil groove has a constant depth in the axial direction of the rotor shaft 32, the cross-sectional area of each oil groove can be easily made constant, and the groove processing is also facilitated. .

  Further, since the bottom 34 b of the inner wall surface 34 a of the notch 34 is orthogonal to the axial direction of the rotor shaft 32, the bottom of the notch 34 over the entire area of the inner wall surface 34 a of the notch 34 in the radial direction of the rotor shaft 32. 34b will be located in the arrangement | positioning area | region Lx of the bearing 41 in an axial direction, and the urging | biasing force to the radial direction of lubricating oil by a centrifugal force becomes large enough. Therefore, the lubricating oil can surely permeate between the fitting surfaces of the bearing 41 and the rotor shaft 32.

  In addition, in the present embodiment, the end surface 32 b of the one end portion 32 a of the rotor shaft 32 is located outward from the arrangement region Lx of the bearing 41 in the axial direction of the rotor shaft 32, and thus the downstream end portion 33 a of the oil passage 33. Lubricating oil flowing out from the rotor shaft 32 can be reliably supplied to the one end face 41 e side of the bearing 41 in the axial direction of the rotor shaft 32. Therefore, the lubrication and cooling performance of the bearing 41 can be reliably improved.

  In addition, in this embodiment, the cylindrical support member 16 that rotatably supports the one end portion 32a of the rotor shaft 32 via the bearing 41 extends from the inner space 16a connected to the oil passage 33 to the outer peripheral surface 16b side. A penetrating through hole 16h is formed. Therefore, the flow of the lubricating oil flowing out from the downstream end portion 33a of the oil passage 33 in the radial direction can cause the air in the vicinity of the lubricating oil to flow in the radial direction passing through the through hole 16h. As a result, by reducing the air pressure in the vicinity of the downstream end of the oil passage 33, the outflow of the lubricating oil can be promoted. In addition, even if foreign matter that easily induces seizure or wear is mixed in the vicinity of the bearing 41, the foreign matter can be discharged together with the lubricating oil from the inner space 16a through the through hole 16h. 10 reliability can be improved.

  Further, the inner space 16a of the cylindrical support member 16 is closed on one side in the axial direction of the rotor shaft 32, and is closed by the one end portion 32a of the rotor shaft 32 on the bearing 41 side and the bearing 41 on the other side in the axial direction. Therefore, the air pressure in the vicinity of the downstream end portion 33a of the oil passage 33 can be reliably reduced, and the outflow of the lubricating oil from the oil passage 33 can be further promoted.

  Thus, in the present embodiment, the lubricating oil is centrifuged in the vicinity of the inner wall surface 34a of the groove-shaped notch 34 extending from the oil passage 33 in the axial center portion of the rotor 13 toward the outer peripheral surface 32c side of the rotor shaft 32. The force is urged outward by the force, and the outflow of the lubricating oil at the downstream end 33a of the oil passage 33 is promoted. Further, the bottom 34b of the inner wall surface 34a of the notch 34 is positioned at least on the outer peripheral surface 32c of the rotor shaft 32 within the arrangement region Lx of the bearing 41 in the axial direction, and between the fitting surfaces of the bearing 41 and the rotor shaft 32. To promote the penetration of lubricating oil. Therefore, a lubrication structure for a rotating machine that can suppress surface damage such as fretting wear at the fitting portion between the rotor shaft 32 and the bearing 41 and increase the lubrication oil flow rate to improve the lubrication and cooling performance of the bearing 41 is provided. can do.

(Second Embodiment)
FIG. 5 shows a cooling structure for an electric motor of a hybrid transaxle for a vehicle according to a second embodiment of the present invention. In addition, although this embodiment differs in the structure of a rotor axial center part from the above-mentioned 1st Embodiment, about another structure, it is similar to the above-mentioned 1st Embodiment. Therefore, in the following description, the same or similar components as those in the first embodiment are denoted by the same reference numerals as the corresponding components shown in FIGS. 1 to 4, and only differences from the first embodiment are described in detail. To do.

  As shown in FIG. 5, the rotor shaft 32 has a hollow pump drive shaft in which power from the engine can be input to a mechanical oil pump 51 such as a gear pump disposed on the other end side of the rotor 13. 61 is provided. Further, between the other end of the rotor shaft 32 and the end of the pump drive shaft 61 in the vicinity thereof and the input shaft of the oil pump 51, the rotor shaft 32 and the pump drive shaft 61 that rotate at high speed (one of which is A known pump input selection mechanism (for example, see Japanese Patent Application Laid-Open No. 10-89446) having a function of selectively selecting a rotating shaft when rotating is provided.

  The pump drive shaft 61 is formed with a plurality of oil holes 61 a penetrating in a radial direction at a plurality of locations in the axial direction, and the inside of the rotor shaft 32 is divided into inner and outer portions partitioned by the pump drive shaft 61. One oil passage 66 and an outer second oil passage 67 are formed.

  Then, the lubricating oil is discharged from the oil pump 51 to at least one of the inner first oil passage 66 and the outer second oil passage 67 of the rotor shaft 32, and the first oil passage 66 and the outer second oil passage 67 are discharged. The oil passage 67 is filled with lubricating oil.

  Similarly to the first embodiment, a plurality of, for example, four groove-shaped notches 34 are radially formed at equal angular intervals at one end portion 32a of the rotor shaft 32 on the bearing 41 side.

  The inner wall surface 34 a (concave notch surface) of each notch 34 has a concave shape that opens outward on the end surface 32 b of the one end portion 32 a of the rotor shaft 32, and the outer peripheral surface 32 c of the rotor shaft 32 from the oil passage 33. It extends outward in the radial direction.

  The bottom 34b of the inner wall surface 34a, which is the inner back surface of the notch 34, is located in the arrangement region Lx of the bearing 41 in the axial direction of the rotor shaft 32 at least on the outer peripheral surface 32c of the rotor shaft 32. 34 is a part of the depth direction (axial direction of the rotor shaft 32) and overlaps with the arrangement region Lx of the bearing 41. Further, the bottom 34b of the inner wall surface 34a of the notch 34 is orthogonal to the axial direction of the rotor shaft 32, and the notch 34 is located in the arrangement region Lx in the axial direction of the rotor shaft 32 over the entire length direction. Is located.

  Also in this embodiment, the lubricating oil is subjected to centrifugal force in the vicinity of the inner wall surface 34a of the groove-shaped notch 34 extending from the second oil passage 67 in the axial center portion of the rotor 13 toward the outer peripheral surface 32c of the rotor shaft 32. Therefore, the oil is urged radially outward to promote the outflow of the lubricating oil at the downstream end 33a of the oil passage 33.

  Further, the bottom 34b of the inner wall surface 34a of the notch 34 is positioned at least within the arrangement region Lx of the bearing 41 in the axial direction on the outer peripheral surface 32c of the rotor shaft 32, and between the fitting surfaces of the bearing 41 and the rotor shaft 32. Can promote the penetration of lubricating oil.

  Therefore, a lubrication structure for a rotating machine that can suppress surface damage such as fretting wear at the fitting portion between the rotor shaft 32 and the bearing 41 and increase the lubrication oil flow rate to improve the lubrication and cooling performance of the bearing 41 is provided. can do.

  In each of the above-described embodiments, the lubrication structure for lubricating and cooling the bearing 41 of the rotor shaft 32 of the electric motor 10 is used. However, the present invention is applicable to the lubrication and cooling of the bearing that supports the rotating shaft of a rotating machine other than the electric motor. Needless to say, it can be applied. However, the present invention is effective for lubrication and cooling of a bearing in a rotating machine in which rotating elements are mounted close to a heat generating portion such as a hybrid transaxle.

  As described above, the present invention urges the lubricating oil radially outward by centrifugal force in the vicinity of the concave notch surface extending from the oil passage in the axial center portion of the rotor toward the outer peripheral surface side of the rotor shaft. Assisting the outflow of the lubricating oil at the downstream end of the oil passage, and positioning the bottom of the notch surface at least within the bearing arrangement region in the axial direction on the outer peripheral surface of the rotor shaft, and fitting between the bearing and the rotor shaft Helps the lubricant to penetrate between surfaces. Therefore, it is possible to provide a lubrication structure for a rotating machine that can suppress surface damage such as fretting wear at the fitting portion between the rotor shaft and the bearing and increase the lubrication oil flow rate to increase the lubrication and cooling performance of the bearing. . The present invention as described above is an axial center cooling system having an oil passage in the axial center portion of the rotor, and is useful in general lubrication structures for rotating machines suitable for vehicle power transmission devices such as hybrid transaxles.

10 Electric motor (rotary machine)
DESCRIPTION OF SYMBOLS 11 Case 12 Stator 13 Rotor 15 Oil storage part 16 Cylindrical support member 16a Inner space 16b Outer peripheral surface 16h Through-hole 21 Stator core 22 Stator coil 31 Rotor main body 32 Rotor shaft 32a One end part 32b End surface 32c Outer peripheral surface 33 Oil path 33a Downstream end part 34 Notch 34a Inner wall surface (concave notch surface)
34b Bottom (bottom of concave notch)
41 Bearing 41a Inner ring 41b Outer ring 41c Steel ball (rolling element)
41e One end face 51 Oil pump 61 Pump drive shaft 61a Oil hole 66 First oil passage 67 Second oil passage (oil passage)

Claims (7)

A rotary machine having a rotor shaft having an oil passage formed in an axial center thereof and rotating around an axis of the rotor shaft, and a bearing that supports the rotor shaft, is provided in the rotary machine, A lubricating structure for a rotating machine capable of feeding lubricating oil through a road,
A concave notch surface is formed on one end portion of the rotor shaft on the bearing side and extends on the end surface of the one end portion and extends from the oil passage toward the outer peripheral surface side of the rotor shaft,
A lubricating structure for a rotary machine, wherein a bottom portion of the notch surface is located in an arrangement region of the bearing in an axial direction of the rotor shaft at least on an outer peripheral surface of the rotor shaft.   2. The at least one oil groove that extends from the oil passage in a radially outward direction of the rotor shaft is formed at one end of the rotor shaft on the bearing side. The lubricating structure of the described rotating machine.   The lubricating structure for a rotary machine according to claim 2, wherein the oil groove has a certain depth in an axial direction of the rotor shaft.   4. The lubricating structure for a rotary machine according to claim 1, wherein a bottom portion of the notch surface is orthogonal to an axial direction of the rotor shaft. 5.   5. The device according to claim 1, wherein an end surface of the one end portion is located outside a region where the bearing is disposed in an axial direction of the rotor shaft. Lubrication structure for rotating machinery.   A cylindrical support member that rotatably supports one end of the rotor shaft on the bearing side via the bearing; the cylindrical support member includes an inner space connected to the oil passage and an outer peripheral surface side; The lubricating structure for a rotary machine according to any one of claims 1 to 5, wherein a through hole is formed so as to extend therethrough.   The inner space of the cylindrical support member is closed on one side in the axial direction, and is closed by one end portion on the bearing side and the bearing on the other side in the axial direction. 6. A lubricating structure for a rotary machine according to 6.

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