Variable-speed drive axle

Abstract

The present disclosure provides a transaxle capable of efficiently cooling an object to be cooled within a housing. A transaxle mounted on a vehicle includes: a shaft that rotates integrally with a coupling gear included in a gear mechanism and a rotor of an electric motor disposed away from the coupling gear in an axial direction; a first oil passage formed in the shaft so as to guide oil, which is scraped up by at least one gear included in the gear mechanism and supplied to the end of the shaft on the side connected to the gear, to a predetermined cooling target in the housing; a second oil passage formed in the shaft so as to guide oil supplied from the pump to the rotor-side end of the shaft to the rotor; and a closing portion provided on the shaft so as to restrict communication between the first oil passage and the second oil passage, the transaxle being capable of efficiently cooling the object to be cooled in the housing.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a transaxle mounted on a vehicle. BACKGROUND

[0002] A hydraulic control device conventionally known in the art supplies oil to an oil supply portion of a vehicle such as a first motor generator and a second motor generator, a power distribution mechanism, and the like, the oil being driven by a mechanical oil pump including at least an engine, and an electric oil pump driven by an electric motor different from the drive source (see, for example, Japanese Patent Application Publication No. 2016-061327). The hydraulic control device includes a first oil passage connected to the mechanical oil pump, a second oil passage connected to the electric oil pump, a first check valve, a second check valve, a third oil passage, and a throttle mechanism. The first check valve is provided between a merging portion of the first and second oil passages and the mechanical oil pump, and allows only the oil to flow from the mechanical oil pump to the oil supply portion. The second check valve is provided between the merging portion and the electric oil pump, and allows only the oil to flow from the electric oil pump to the oil supply portion. The third oil passage is provided between the merging portion and the electric oil pump so as to communicate the merging portion and the electric oil pump while bypassing the second check valve. The throttle mechanism is provided in the third oil passage so as to restrict the flow rate of the oil discharged from the mechanical oil pump.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2016-061327

[0004] According to the above-described conventional hydraulic control device, more oil can be supplied from the mechanical oil pump and the electric oil pump to the oil supply portion as a cooling medium. However, in a case where the temperature of the oil from the mechanical oil pump and the temperature of the oil from the electric oil pump are different, the temperature of the oil becomes high at the merging portion of the first and second oil passages, and it can become impossible to efficiently cool the oil supply portion. SUMMARY

[0005] The main object of the present disclosure is to provide a transaxle capable of efficiently cooling a cooling object in a housing.

[0006] The variable drive axle of the present disclosure is mounted on a vehicle, and includes a motor, a gear mechanism including at least a differential gear and coupled to the motor, a housing that houses the motor and the gear mechanism, and a pump that sucks and discharges oil accumulated in the housing. Also, the variable drive axle includes a shaft that rotates integrally with a coupling gear included in the gear mechanism and a rotor of the motor arranged apart from the coupling gear in the axial direction. The shaft has a first oil passage, a second oil passage, and a closed portion. The first oil passage is formed in the shaft in such a manner that oil scraped up by at least one gear included in the gear mechanism and supplied to an end portion of the coupling gear of the shaft is guided to a prescribed cooling target in the housing. The second oil passage is formed in the shaft in such a manner that oil supplied from the pump to an end portion of the rotor is guided to the rotor. The closed portion is provided to the shaft in such a manner as to restrict communication between the first oil passage and the second oil passage.

[0007] Thus, the oil scraped up by at least one gear of the gear mechanism can be guided from the first oil passage to the prescribed cooling target in the housing without mixing with the oil in the second oil passage, and the oil from the pump can be guided from the second oil passage to the rotor of the motor as the other cooling target in the housing. As a result, the temperature of one of the oil in the first oil passage and the oil in the second oil passage can be suppressed from rising due to the temperature of the other, thereby efficiently cooling the prescribed cooling target in the housing and the motor as the other cooling target. BRIEF DESCRIPTION OF DRAWINGS

[0008] Figure 1 is a diagram showing a brief configuration of a vehicle including the variable drive axle of the present disclosure.

[0009] Figure 2 is an enlarged view showing the variable drive axle of the present disclosure. DETAILED DESCRIPTION

[0010] Next, a mode for carrying out the invention of the present disclosure will be described with reference to the drawings.

[0011] Figure 1 is a diagram showing a brief configuration of a vehicle 1 including the variable drive axle 20 of the present disclosure. The vehicle 1 shown in this diagram is a front-wheel drive hybrid vehicle, and includes an engine (internal combustion engine) 10, a variable drive axle 20 as a power transmission device including motor generators MG1 and MG2 and coupled to the engine 10, and a battery (power storage device) not shown that exchanges electric power with the motor generators MG1 and MG2 of the variable drive axle 20. The engine 10 is a gasoline engine that combusts a mixture of gasoline (hydrocarbon fuel) and air in a plurality of combustion chambers and converts reciprocating motion of a piston accompanying combustion of the mixture into rotational motion of a crankshaft. However, the engine 10 can also be an LPG engine or a diesel engine.

[0012] As Figure 1As shown, the transaxle 20 includes a planetary gear 30, a differential gear 39, and a case 40 that houses these members, in addition to the motor generators MG1 and MG2. The motor generator MG1 (first motor) is a synchronous generator motor (three-phase alternating-current motor) that includes a stator SI and a rotor Rl, and mainly functions as a generator that converts at least a portion of the power from the load-operated engine 10 into electric power. The motor generator MG2 (second motor) is a synchronous generator motor (three-phase alternating-current motor) that includes a stator S2 and a rotor R2, and mainly functions as a motor that generates a drive torque by being driven by electric power from at least either of a battery and the motor generator MG1. The motor generators MG1 and MG2 exchange electric power with the above-mentioned battery via a power control device (PCU) that is not shown and includes an inverter, and exchange electric power with each other via the power control device.

[0013] The planetary gear 30 includes a sun gear (first rotary member) 31, a ring gear (second rotary member) 32, and a planetary carrier (third rotary member) 34 that rotatably supports a plurality of pinions 33. As shown in FIG. 2, the sun gear 31 is connected to the rotor Rl of the motor generator MG1 via a hollow rotor shaft RS. The planetary carrier 34 is coaxially fixed to a carrier shaft CS, and is connected to the crankshaft of the engine 10 via the carrier shaft CS and the damper mechanism 25. The ring gear 32 is integrated with a countershaft drive gear 35 that is an output member, and both of them rotate coaxially and integrally. Figure 1 As shown, the sun gear 31 is connected to the rotor Rl of the motor generator MG1 via a hollow rotor shaft RS. The planetary carrier 34 is coaxially fixed to a carrier shaft CS, and is connected to the crankshaft of the engine 10 via the carrier shaft CS and the damper mechanism 25. The ring gear 32 is integrated with a countershaft drive gear 35 that is an output member, and both of them rotate coaxially and integrally.

[0014] The countershaft drive gear 35 is connected to left and right wheels (drive wheels) W via a countershaft driven gear 36 that is engaged with the countershaft drive gear 35, a drive pinion (end drive gear) 37 that rotates integrally with the countershaft driven gear 36, a differential ring gear 39r that is engaged with the drive pinion 37 and rotates integrally with a differential case of the differential gear 39, the differential gear 39, and a drive shaft DS. The gear mechanism of the transaxle 20, i.e., the gear train from the planetary gear 30 and the countershaft drive gear 35 to the differential gear 39, connects the engine 10 and the motor generator MG1 to each other, and transmits a portion of the output torque of the engine 10 that is a power generation source to the drive shaft DS and the wheels W.

[0015] In addition, in the rotor R2 of the motor generator MG2, a connection gear (reduction gear) 38 is connected (fixed) to the rotor R2 in a manner that the connection gear 38 is away from the rotor R2 in the axial direction of a motor shaft MS. That is, the motor shaft MS rotates coaxially and integrally with the connection gear 38 included in the gear mechanism of the transaxle 20 and the rotor R2 of the motor generator MG2 that is arranged away from the connection gear 38 in the axial direction. The connection gear 38 has a smaller number of teeth than the countershaft driven gear 36, and is engaged with the countershaft driven gear 36.

[0016] Thus, the motor generator MG2 is linked with the drive shafts DS and the wheels W via the joint gear 38, the countershaft driven gear 36, the drive pinion 37, the differential ring gear 39r, and the differential gear 39. Also, the motor generator MG2 functions alone or in cooperation with the engine 10 as a power generation source that outputs a drive torque (driving force) to the drive shafts DS and the wheels W, and outputs a regenerative braking torque at the time of braking of the vehicle 1.

[0017] The housing 40 of the transaxle 20 includes a first housing 41, a second housing 42, and a cover (third housing) 45. The first and second housings 41, 42, and the cover 45 are each a cast product formed of, for example, an aluminum alloy or a steel material. The first housing 41 is fastened (joined) to the engine block of the engine 10 by a plurality of bolts. The second housing 42 is fastened (joined) to the first housing 41 by a plurality of bolts, and constitutes a housing main body together with the first housing 41. Also, the second housing 42 has a partition wall 42w that partitions the inside of the housing 40 (housing main body) into two. The cover 45 is fastened (joined) to the second housing 42 by a plurality of bolts in a manner so as to cover the open end of the second housing 42 on the side opposite the first housing 41.

[0018] In addition, in the present embodiment, the carrier shaft CS of the carrier 34 that is fixed to the planetary gear 30 is supported by a bearing (for example, a needle bearing) BO held by the first housing 41. Also, the rotor shaft RS of the rotor Rl of the motor generator MGl and the sun gear 31 that are fixed to the planetary gear 30 are supported by a bearing (for example, a ball bearing) Bl held by the partition wall 42w of the second housing 42 and a bearing (for example, a ball bearing) B2 held by the cover 45. In addition, the countershaft that is fixed to the countershaft driven gear 36 and the drive pinion 37 is supported by a bearing (for example, a tapered roller bearing) B3 held by the first housing 41 and a bearing (for example, a tapered roller bearing) B4 held by the partition wall 42w of the second housing 42.

[0019] Also, the motor shaft MS that rotates integrally with the rotor R2 and the joint gear 38 is supported, for example, by bearings B5, B6, and B7 that are ball bearings. That is, the end portion (right end in FIG. 1) of the motor shaft MS on the side of the joint gear 38 is supported by a bearing (first bearing) B5 held by the first housing 41. In addition, the end portion (left end in FIG. 1) of the motor shaft MS on the side of the rotor R2 is supported by a bearing (second bearing) B6 held by the partition wall 42w of the second housing 42. Also, the end portion (right end in FIG. 1) of the motor shaft MS on the side of the joint gear 38 is supported by a bearing (third bearing) B7 held by the cover 45. Figure 1 Figure 1 ​The motor shaft MS is supported by a bearing (first bearing) B5 held by the first housing 41 at the left end in FIG. 1. Also, the motor shaft MS is supported by a bearing (second bearing) B7 held by the cover 45 between the coupling gear 38 and the rotor R2 in the axial direction. Further, the differential case of the differential gear 39 is supported by a bearing (for example, a tapered roller bearing) B8 held by the first housing 41 and a bearing (for example, a tapered roller bearing) B9 held by the second housing 42.

[0020] As shown in FIG. 1, the gear mechanism, that is, the gear train from the planetary gear 30, the countershaft drive gear 35 to the differential gear 39 is arranged in the gear chamber 44. Further, the motor generators MGl, MG2 are arranged in the motor chamber 46. Also, a working oil storage portion that stores working oil (ATF) as a lubrication and cooling medium is partitioned in the lower portion of the motor chamber 46. A filter (not shown) and an electric oil pump 60 are arranged in the working oil storage portion. Figure 1 The filter is fixed in the working oil storage portion, for example, in a manner that a suction port provided in the bottom portion is opened downward. Further, a suction port of the electric oil pump 60 is connected to an oil flow outlet of the filter, and a hollow oil pipe (not shown) is connected to a discharge port of the electric oil pump 60. The electric oil pump 60 sucks the working oil in the working oil storage portion, and pressurizes the sucked working oil via the oil pipe and the like to an oil cooler 70 of an air-cooled or water-cooled type. The working oil from the electric oil pump 60 is cooled by the oil cooler 70 to, for example, a normal temperature vicinity (about 20 to 25°C), and is supplied to lubrication and cooling targets in the housings 40, that is, the gear chamber 44 and the motor chamber 46 via an oil passage and the like formed in the cover 45. The lubrication and cooling targets include the motor generators MGl, MG2, the planetary gear 30, the gears 35 to 39r, the differential gear 39, the bearings B0 to B9, and the like.

[0021]

[0022] ​The working oil supplied from the electric oil pump 60 into the motor chamber 46 flows down toward the working oil storage portion in the motor chamber 46 through the lubrication and cooling targets such as the motor generators MGl, MG2, bearings B2, B7. Also, the working oil supplied from the electric oil pump 60 into the gear chamber 44 flows down toward the lower portion in the gear chamber 44 through the lubrication and cooling targets in the gear chamber 44 such as the planetary gear 30, gears 35-39r, differential gear 39, bearings BO, Bl, B3-B6, B8, B9. Also, the working oil flowing down in the gear chamber 44 is scraped upward by the differential ring gear 39r, the coupling gear 38, the pinion gear 36, the pinion drive gear 35, and the like, and is supplied to the lubrication and cooling targets in the gear chamber 44. Also, a plurality of oil holes, not shown, are provided in the partition wall 42w of the second housing 42 in a manner corresponding to the pinion drive gear 35, the coupling gear 38, or the differential ring gear 39r, respectively. A part of the oil scraped in the gear chamber 44 flows into the motor chamber 46 through these oil holes. Also, a plurality of communication holes, not shown, are formed in the partition wall 42w to communicate the lower portion in the motor chamber 46, i.e., the working oil storage portion, and the lower portion in the gear chamber 44.

[0023] Figure 2 is an enlarged view showing the main part of the transaxle 20. As shown in this drawing, the motor shaft MS includes a first shaft MSI made of metal and a second shaft MS2 made of metal coaxially coupled to the first shaft MSI in an integral rotation manner. In the present embodiment, the coupling gear 38 is integrally formed in the first shaft MSI. However, the coupling gear 38 can be formed separately from the first shaft MSI and fixed to the first shaft MSI. Also, the first shaft MSI has a first oil passage OPl. The first oil passage OPl is a circular hole opened at one end (right end in Figure 2 ) of the first shaft MSI and extending along the axis of the first shaft MSI.

[0024] Also, a closing portion C is formed at the other end (left end in Figure 2 ) of the first shaft MSI to close the end portion of the first oil passage OPl on the side opposite to the opening. Also, a plurality of first oil supply holes HI are formed at intervals in the circumferential direction in the first shaft MSI. Each first oil supply hole HI is opened in the vicinity of the closing portion C and the inner peripheral surface of the first shaft MSI so as to communicate with the first oil passage OPl, and extends in the radial direction of the first shaft MSI and is opened in the outer peripheral surface of the first shaft MSI. Further, only one first oil supply hole HI can be formed in the first shaft MSI.

[0025] The second shaft MS2 is inserted into the core center hole of the rotor R2 (rotor core) of the motor generator MG2 and is fixed to the rotor R2 by a shrink fit or press fit. As shown in Figure 2As shown, the second shaft MS2 is hollow and has a through hole (circular hole) extending along the axis of the second shaft MS2 and dividing the second oil passage OP2. Furthermore, at the center of the long side of the second shaft MS2, a plurality of second oil supply holes H2 are formed at circumferential intervals (e.g., eight in this embodiment). Each second oil supply hole H2 opens on the inner circumferential surface of the second shaft MS2 to communicate with the second oil passage OP2, and extends radially along the second shaft MS2 and opens on the outer circumferential surface of the second shaft MS2 surrounded by the inner circumferential surface of the rotor R2.

[0026] like Figure 2 As shown, the end of the closed portion C of the first shaft MS1 is fitted into the through hole of the second shaft MS2 (the right end in the figure) from one end of the second shaft MS2. In this embodiment, splines are formed on the outer peripheral surface of the end of the closed portion C of the first shaft MS1 and the inner peripheral surface of the second shaft MS2. The splines of the first and second shafts MS1 and MS2 mesh with each other to form a spline fitting portion SP. Furthermore, the outer peripheral surface of the first shaft MS1 and the inner peripheral surface of the second shaft MS2 are located on the connecting gear 38 side of the spline fitting portion SP (…). Figure 2 The two shafts (MS1, MS2, MS2, MS2, MS2, MS2, MS2, MS2, MS2, and MS2) are in close contact to form a socket joint SJ. Furthermore, one end face of the second shaft MS2 abuts against the flange FL formed on the first shaft MS1. Additionally, a friction damper FD is disposed between the outer circumferential surface of the first shaft MS1 and the inner circumferential surface of the second shaft MS2, and axially between the socket joint SJ and the flange FL.

[0027] Thus, the first and second shafts MS1 and MS2 are connected in the rotational direction via the spline fitting part SP and coaxially connected via the socket joint part SJ. Furthermore, when the first and second shafts MS1 and MS2 are connected, the closing part C formed at the other end of the first shaft MS1 restricts the communication between the first oil passage OP1 of the first shaft MS1 and the second oil passage OP2 of the second shaft MS2. Additionally, one end of the first shaft MS1 ( Figure 2 The right end of the second shaft MS2 (on the side of the connecting gear 38) forms the end of the motor shaft MS, supported by the bearing B5 held by the first housing 41. Furthermore, one end of the second shaft MS2 (on the right end) Figure 2 The right end of the second shaft MS2 is supported axially between the connecting gear 38 (flange FL) and the socket joint SJ (rotor R2) by a bearing B6 held by a partition 42w of the second housing 42. Additionally, the other end of the second shaft MS2 ( Figure 2 The left end of the motor shaft MS forms the rotor R2 side end, which is supported by bearing B7 held by cover 45.

[0028] When the motor shafts MS, including the first and second shafts MS1 and MS2, are disposed within the housing 40, the first oil passage OP1 of the first shaft MS1 opens near the bearing B5, and the second oil passage OP2 of the second shaft MS2 opens near the bearing B7. Furthermore, an extension protrusion 45e extending from the cover 45 is inserted into the opening of the second oil passage OP2. An oil hole 45h is formed in the extension protrusion 45e, communicating with the oil passage 45p formed in the cover 45 and opening at the front end of the extension protrusion 45e.

[0029] And, as Figure 2 As shown, each first oil supply hole H1 of the first shaft MS1 is axially positioned between the end face ES of the connecting gear 38 on the bearing (intermediate bearing) B6 and the rotor R2, and opens on the outer peripheral surface of the first shaft MS1 forming the socket joint SJ. Additionally, each second oil supply hole H2 of the second shaft MS2 is located on the rotor RS side of the motor shaft MS axially above each first oil supply hole H1. ​ The left side of the rotor R2 (rotor core) is opposite the central portion of the inner circumferential surface of the rotor R2 (rotor core) in the axial direction, and is connected to the corresponding refrigerant passage of the rotor R2 via a connecting passage formed in the rotor R2. In this embodiment, multiple refrigerant passages are formed circumferentially at intervals in the rotor R2 (rotor core) in such a way that they extend radially outward from the core center hole. Furthermore, the closing portion C of the first shaft MS1 restricts the connection between the first oil supply hole H1 and the second oil supply hole H2 in the axial direction, and more specifically, between the first oil supply hole H1 and the end face ES of the connecting gear side 38 of the rotor R2 in the axial direction.

[0030] During vehicle 1 operation, including the aforementioned transmission drive axle 20, working oil scraped up by the differential gear ring 39r, connecting gear 38, and countershaft drive gear 35 within the gear chamber 44, and working oil passing through bearing B5, flows from an opening at one end of the first shaft MS1 into the first oil passage OP1 of the rotating motor shaft MS, i.e., the first shaft MS1. The working oil that has flowed into the first oil passage OP1 flows from the first oil passage OP1 into each first oil supply hole H1 due to centrifugal force, supplying the socket joint SJ, which is the object to be cooled. Thus, the working oil scraped up within the gear chamber 44 can effectively cool the socket joint SJ (metal contact portion), where the outer peripheral surface of the first shaft MS1 and the inner peripheral surface of the second shaft MS2 are in close contact. The working oil supplied to the socket joint SJ flows downwards into the lower part of the gear chamber 44 through the small gaps between the outer peripheral surface of the first shaft MS1 and the inner peripheral surface of the second shaft MS2, the friction damper FD, and the gap between the inner ring of bearing B6 and the partition wall 42w.

[0031] Further, during the travel of the vehicle 1, the working oil discharged from the electric oil pump 60 and cooled by the oil cooler 70 is supplied to the opening on the other end side of the rotating motor shaft MS, i.e., the second oil passage OP2, via the oil passage 45p of the cover 45 and the oil hole 45h of the extension protrusion 45e. The working oil having flowed into the second oil passage OP2 flows from the second oil passage OP2 into each second oil supply hole H2 due to centrifugal force, and flows from each second oil supply hole H2 into the corresponding refrigerant passage of the rotor R2 via the communication path formed in the rotor R2. As a result, the rotor R2 (rotor core and permanent magnet) as a whole can be cooled well by the working oil circulated in the plurality of refrigerant passages and the like. The working oil supplied to the rotor R2 takes heat from the rotor R2, flows out from the openings of each refrigerant passage to the outside, and scatters to the radial outside due to centrifugal force. The working oil scattered to the outside of the rotor R2 flows down to the working oil storage portion in the motor chamber 46.

[0032] Further, in the transaxle 20, the closed portion C formed on the other end of the first shaft MS1 restricts the communication of the first oil passage OP1 of the first shaft MS1 and the second oil passage OP2 of the second shaft MS2. Therefore, the working oil scraped up in the gear chamber 44 and supplied into the first oil passage OP1 and the working oil supplied to the second oil passage OP2 from the electric oil pump 60 via the oil cooler 70 do not mix in the motor shaft MS. Thus, the working oil scraped up in the gear chamber 44 can be supplied from the first oil supply hole H1 to the socket joint SJ as a prescribed cooling target, and the working oil from the electric oil pump 60 cooled by the oil cooler 70 can be supplied to the rotor R2 to cool the motor generator MG2 as another cooling target well. Further, a part of the working oil supplied to the second oil passage OP2 from the electric oil pump 60 via the oil cooler 70 flows into the socket joint SJ through the spline fitting portion SP. Thus, the spline fitting portion SP and the socket joint SJ can be cooled by the part of the working oil from the electric oil pump 60.

[0033] As explained above, the transaxle 20 mounted on the vehicle 1 includes the motor generator MG2, a gear mechanism including at least the differential gear 39 and coupled to the motor generator MG2, a housing 40 that houses the motor generator MG2 and the gear mechanism, and an electric oil pump 60 that sucks and discharges the working oil stored in the housing 40. Also, the transaxle 20 includes a motor shaft MS that rotates integrally with the coupling gear 38 included in the gear mechanism and the rotor R2 of the motor generator MG2 disposed apart from the coupling gear 38 in the axial direction. The motor shaft MS has a first oil passage OPl, a second oil passage OP2, and a closed portion C. The first oil passage OPl is formed in the motor shaft MS (first shaft MSI) so as to guide the working oil scraped up by at least one gear included in the gear mechanism such as the differential gear ring 39r to the end portion (one end of the first shaft MSI) of the coupling gear 38 side of the motor shaft MS to the socket joint SJ that is a cooling target in the housing 40. The second oil passage OP2 is formed in the motor shaft MS (second shaft MS2) so as to guide the working oil supplied from the electric oil pump 60 to the end portion (the other end of the second shaft MS2) of the rotor R2 side of the motor shaft MS to the rotor R2. The closed portion C is provided to the motor shaft MS (first shaft MSI) so as to restrict the communication of the first oil passage OPl and the second oil passage OP2.

[0034] Thus, it is possible to guide the working oil scraped up by the differential gear ring 39r or the like from the first oil passage OPl to the socket joint SJ that is a cooling target without mixing the working oil in the first oil passage OPl and the working oil in the second oil passage OP2. Also, it is possible to guide the working oil from the electric oil pump 60 from the second oil passage OP2 to the rotor R2 of the motor generator MG2 that is another cooling target in the housing 40. As a result, it is possible to suppress the temperature of the working oil in the second oil passage OP2 cooled by the oil cooler 70 from increasing due to the temperature increase of the working oil in the first oil passage OPl, thereby efficiently cooling the socket joint SJ and the motor generator MG2 that are cooling targets.

[0035] In addition, the motor shaft MS (first or second shaft MSI, MS2) includes a first oil supply hole HI that communicates with the first oil passage OPl and supplies the working oil to the socket joint SJ side, and a second oil supply hole H2 that communicates with the second oil passage OP2 and opens in the outer peripheral surface of the motor shaft MS (second shaft MS2) surrounded by the inner peripheral surface of the rotor R2. Also, the closed portion C is disposed between the first oil supply hole HI and the second oil supply hole H2 in the axial direction. In addition, in the transaxle 20, the working oil discharged from the electric oil pump 60 is supplied to the second oil passage OP2 via the oil cooler 70.

[0036] Thus, the working oil discharged from the electric oil pump 60 and cooled by the oil cooler 70 can be supplied to the rotor R2 without being warmed up by mixing with the working oil scraped up in the gear chamber 44, so that the motor generator MG2 is cooled well. Further, in the above-described transfer 20, the temperature of the working oil flowing out from the oil cooler 70 can be detected, and the oil cooler 70 or the like can be controlled so that the detected temperature becomes a desired temperature.

[0037] Further, the transfer 20 includes a bearing (first bearing) B5 that supports an end of the first shaft MS1, i.e., an end portion of the motor shaft MS on the joint gear 38 side, a bearing (second bearing) B7 that supports the other end of the second shaft MS2, i.e., an end portion of the motor shaft MS on the rotor R2 side, and a bearing (intermediate bearing) B6 that supports the motor shaft MS between the joint gear 38 and the rotor R2 in the axial direction. Further, the first oil supply hole H1 is disposed between the bearing B6 and an end surface ES of the joint gear 38 on the rotor R2 side in the axial direction.

[0038] Thus, the relatively long motor shaft MS that rotates integrally with the joint gear 38 and the rotor R2 of the motor generator MG2 can be stably supported, and the working oil scraped up in the gear chamber 44 (the housing 40) can be supplied from the first oil supply hole H1 to the socket joint SJ (cooling target) between the bearing B6 and the rotor R2 in the axial direction. However, the cooling target of the working oil supplied to the first oil passage OPl can be arbitrarily decided within a range in which the working oil can be supplied from the first oil passage OPl, and is not limited to the socket joint SJ.

[0039] Further, in the transfer 20, the motor shaft MS includes a first shaft MS1 that has the first oil passage OPl and rotates integrally with the joint gear 38, and a second shaft MS2 that has the second oil passage OP2 and is fixed to the rotor R2. Further, the first shaft MS1 is fitted into the second oil passage OP2 in a manner of rotating integrally with the second shaft MS2. Further, a closing portion C is formed at an end portion of the first shaft MS1 on the second shaft MS2 side.

[0040] Thus, the first oil passage OPl, the second oil passage OP2, and the closing portion C can be easily formed in the motor shaft MS. However, in the transfer 20, the closing portion C can be formed at an end portion of the second shaft MS1 on the first shaft MS1 side, and the motor shaft MS can be a single shaft member that includes the first oil passage OPl, the second oil passage OP2, and the closing portion C.

[0041] Furthermore, the first and second shafts MS1 and MS2 are connected in the rotational direction via a spline engagement SP, and are coaxially connected on the side of the connecting gear 38 of the spline engagement SP via a socket joint SJ where the outer peripheral surface of the first shaft MS1 and the inner peripheral surface of the second shaft MS2 are in close contact. Additionally, in the transmission drive axle 20, a portion of the working oil supplied to the second oil passage OP2 flows into the socket joint SJ through the spline engagement SP.

[0042] Therefore, the socket joint SJ can be cooled by the working oil scraped inside the gear chamber 44, and a portion of the working oil from the electric oil pump 60 can also cool the spline engagement SP and the socket joint SJ. As a result, wear on the first and second shafts MS1 and MS2 in the spline engagement SP and the socket joint SJ can be effectively suppressed.

[0043] Furthermore, vehicle 1 can also be a plug-in hybrid electric vehicle (PHEV) or a single-motor hybrid electric vehicle. Additionally, the transmission drive axle 20 can be modified to be used in battery electric vehicles (BEVs) or fuel cell electric vehicles (FCEVs).

[0044] Obviously, the invention disclosed herein is not limited to any of the above-described embodiments, and various modifications can be made within the scope of this disclosure. Furthermore, the above-described embodiments are merely one specific way of the invention described in the description of the invention, and do not limit the elements of the invention described in the description of the invention.

[0045] The invention disclosed herein can be used in industries such as the manufacturing of variable speed drive axles.

Claims

1. A variable drive axle comprising a motor, a gear mechanism including at least a differential gear and coupled to the motor, a housing that houses the motor and the gear mechanism, and a pump that sucks oil accumulated in the housing and discharges the oil, and is mounted on a vehicle, wherein, Possessing: a shaft that rotates integrally with a pinion gear included in the gear mechanism and a rotor of the motor disposed apart from the pinion gear in the axial direction; a first oil passage formed in the shaft in a manner to guide oil scraped up by at least one gear included in the gear mechanism and supplied to an end portion of the pinion gear side of the shaft to a prescribed cooling object in the housing; a second oil passage formed in the shaft in a manner to guide oil supplied from the pump to an end portion of the rotor side of the shaft to the rotor; and a closure portion provided to the shaft in a manner to restrict communication of the first oil passage and the second oil passage.

2. The transaxle according to claim 1, wherein the shaft includes a first oil supply hole that communicates with the first oil passage and supplies oil to the cooling object side, and a second oil supply hole that communicates with the second oil passage and opens in an outer peripheral surface of the shaft surrounded by an inner peripheral surface of the rotor, the closure portion is disposed between the first oil supply hole and the second oil supply hole in the axial direction, oil discharged from the pump is supplied to the second oil passage via an oil cooler.

3. The transverse drive axle of claim 2 wherein, Further possessing: a first bearing that supports the end portion of the pinion gear side of the shaft; a second bearing that supports the end portion of the rotor side of the shaft; and an intermediate bearing that supports the shaft between the pinion gear and the rotor in the axial direction, the first oil supply hole is disposed between the intermediate bearing and an end surface of the pinion gear side of the rotor in the axial direction.

4. The transaxle according to any one of claims 1 to 3, wherein the shaft includes a first shaft that has the first oil passage and rotates integrally with the pinion gear, and a second shaft that has the second oil passage and is fixed to the rotor, the first shaft is fitted into the second oil passage in a manner to rotate integrally with the second shaft, the closure portion is formed in an end portion of the second shaft side of the first shaft.

5. The transaxle according to claim 4, wherein the first shaft and the second shaft are joined in a rotational direction by means of a spline fitting portion, and are coaxially joined on the pinion gear side of the spline fitting portion by means of a spigot joint portion in which an outer peripheral surface of the first shaft and an inner peripheral surface of the second shaft are in close contact, the cooling object is the spigot joint portion, a portion of oil supplied to the second oil passage flows into the spigot joint portion through the spline fitting portion.

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