Drive apparatus for vehicle

A vehicle drive apparatus includes a first electric motor, a power distributing mechanism, a second electric motor, and a step-variable power transmission. A power transmitting portion includes a second case, accommodating the second electric motor and the automatic power transmission. One end of an input shaft of the automatic power transmission faces a drive apparatus output shaft, which is supported with a first support wall mounted on the second case, the second electric motor being accommodated in a compartment opposite to the automatic power transmission with respect to the first support wall, and one end of a second rotor supporting shaft of the second electric motor faces the automatic power transmission, which is supported with a second support wall mounted on the second case. The automatic power transmission and second electric motor can be unitized as one power transmitting portion, improving assembling workability of the drive apparatus.

TECHNICAL FIELD

The present invention relates to a drive apparatus for vehicle, and more particularly, to technologies of improving assembling workability of the drive apparatus including a motor and a gear device, and technologies of preventing a larger device size in the drive apparatus including the motor and a rotating device having a rotating shaft.

BACKGROUND ART

A drive apparatus including a first motor, a first gear device, a second motor and a second gear device has heretofore been known. For instance, it corresponds to a drive apparatus for hybrid vehicle disclosed in Patent Publication 1. With the apparatus disclosed in Patent Publication 1, a planetary gear unit functioning as a power distributing device is provided as the first gear device through which power, delivered from an engine, is transferred to the first electric motor and the second gear device in split modes. Further, the second gear device includes a planetary gear unit, functioning as a gear reduction mechanism, through which the rotation is reduced in speed and transferred to drive wheels. In addition, the first electric motor mainly functions as an electric power generator, and the second electric motor mainly functions as an electric motor to generate auxiliary power to drive the drive wheels separately from power delivered from the engine.

In the above Patent Publication 1, the drive apparatus includes a case having first to third cases. The first case accommodates therein the first motor and the first gear device, the second case accommodates therein the second motor, and the third case accommodates therein the second gear device. In assembling the drive apparatus with such structure, the first motor and the first gear device are accommodated in the first case to form a first unit, and the second motor is accommodated in the second case to form a second unit, while accommodating the second gear device in the third case prepares a third unit. Then, the first unit and the second unit are assembled to both sides of the second unit, respectively.[Patent Publication 1] Japanese Patent Unexamined Application Publication No. 2003-191759[Patent Publication 2] Japanese Patent Unexamined Application Publication No. 2003-191761[Patent Publication 3] Japanese Patent Unexamined Application Publication No. 2003-336725

With the second motor and the second gear device formed in the separate units like those disclosed in Patent Publication 1, the number of split components tends to increase with the resultant problem with a deterioration in assembling workability.

The present invention has been made on the background with the above problem in mind and has an object to provide a drive apparatus for vehicle having improved assembling workability.

Meanwhile, another drive apparatus including a motor and a rotating device having a rotating shaft has heretofore been known (see, for instance, Patent Publication 1). In the Patent Publication 1, the planetary gear unit functioning as the gear reduction mechanism is placed adjacent to the motor as the rotating device such that the rotating shaft of the planetary gear unit is supported with a support wall mounted on the case.

With such a drive apparatus including the motor and the rotating device having the rotating shaft, a stator of the motor is fastened to the case via a spacer by bolt clenching. In such a case, if the support wall and the spacer are separately fixed to the case, respective mounting spaces need to be prepared with the resultant probability of causing the drive apparatus to increase in size (especially in a large size in diameter).

It is therefore a second object of the present invention to provide a drive apparatus for vehicle that can prevent the progress of a large size, even in a case where a spacer is placed between a stator of a motor and a case, and a rotating shaft of a rotating device is supported with a support wall mounted on the case.

DISCLOSURE OF THE INVENTION

For achieving the above first object, the invention recited in the claim1is featured by a drive apparatus for vehicle having a first electric motor, a first gear device, a second electric motor and a second gear device, comprising (i) one power transmitting portion including a case, and the second electric motor and the second gear device accommodated in the case; (ii) at least one end of the second gear device being supported with a first support wall mounted on the case; (iii) the second electric motor being accommodated in a compartment formed in the case in opposition to the second gear device with respect to the first support wall for accommodating therein the second electric motor; and (iv) the second electric motor having a rotary shaft being supported with the second support wall fixed to the case on a side opposite to the first support wall with respect to the second electric motor.

According to the first invention, the second gear device and the second electric motor are accommodated in one case and the first support wall and second support wall, mounted on the case, support the second gear device and the rotating shaft of the second electric motor, respectively. This enables the second gear device and the second electric motor to be unitized as one power transmitting portion, resulting in the improvement of assembling workability of the drive apparatus.

Preferably, the drive apparatus for vehicle is, as the invention recited in the claim2, constructed such that the other power transmitting portion includes the first electric motor and the first gear device. This allows the drive apparatus to include the two power transmitting portions. Thus, after assembling the two power transmitting portions, respectively, mere coupling these component parts to each other enables the drive apparatus to be assembled. This results in a further increase in assembling workability of the drive apparatus.

Preferably, the drive apparatus for vehicle is, as the invention recited in the claim3, constructed such that the other power transmitting portion has a second case; the second case includes a wall member partitioning the second case into a first accommodating compartment accommodating the first electric motor and a second accommodating compartment accommodating the first gear device; and the first electric motor and the first gear device are coupled to each other for power transmitting capability with the wall member intervening therebetween. With such structure, with maintaining the power transmission between the first gear device and the first electric motor, the first gear device can be accommodated from one side of the case while the first electric motor can be accommodated from other side of the case, resulting in further increase of the assembling workability.

The drive apparatus for vehicle is, as the invention recited in the claim4, preferably constructed such that the one transmitting portion and the other power transmitting portion are connected to each other. However, a third power transmitting portion can be intervened between the both power transmitting portions.

The invention recited in the claim1is, as recited in the claim5, particularly effective for a case where the second gear device includes a plurality of planetary gear units. With the use of such a plurality of planetary gear units, the number of component parts tends to increase with the resultant problem of assembling workability. However, even if the second gear device includes the plurality of planetary gear units, the structure of the invention recited in the claim1enables the second electric motor and the second gear device to be formed as one unit.

That is, after the second gear device is assembled in the case, the first support wall and the second electric motor are accommodated, followed by the second support wall being mounted. Thus, the second electric motor and the second gear device can be constructed as one unit. Accordingly, no need arises for the second electric motor and the second gear device to be formed in separate units, minimizing the total number of units forming the drive apparatus with the resultant improvement in assembling workability.

Preferably, as recited in the claim6, the drive apparatus for vehicle is constructed such that the first support wall has an outer circumferential surface held in abutting contact with an inner circumferential surface of the case; and the rotary shaft of the second electric motor is rotatably supported with the first support wall. With such structure, since the first support wall is radially positioned in high accuracy, the axis position of the rotor support shaft of the second electric motor supported by the first support wall can be supported with high accuracy.

Preferably, as recited in the claim7, the drive apparatus for vehicle is constructed such that the outer circumferential surface of the second support wall is held in abutting contact with the inner circumferential surface of the case. With such structure, the rotor support shaft of the second electric motor is supported with the two support walls fixed in the case on highly precise radial positions on both sides of the second electric motor. Thus, the rotor support shaft of the second electric motor can have an axial position fixed in a further increased precision.

Preferably, as recited in the claim8, the second support wall is formed with a concaved portion axially concaved for accommodating a stator coil of the second electric motor, and an outer circumferential margin of the second support wall being connected to an opening margin of the concaved portion. With such arrangement, accommodation of the stator coil of the second electric motor in the axially concaved portion enables effective utilization of the space, resulting in shortened axial length of the drive apparatus.

Preferably, as recited in the claim9, the first gear device is rotatably supported with the wall member of the second case; as recited in the claim10, the first support wall is fixed to the case by bolts; and as recited in the claim11, the second support wall is fixed to the case by bolts. With these structures, both the first support wall and the second support wall can be easily assembled to the case.

For achieving the above second object, the invention recited in the claim12is featured by a drive apparatus for vehicle, comprising (i) an electric motor; (ii) a rotating device having a rotating shaft; (iii) a stator of the electric motor being mounted on a case via a spacer; and (iv) the rotating shaft of the rotating device being rotatably supported with a support wall mounted on the case, (v) wherein the spacer and the support wall are integrally formed with each other.

For achieving the above object, the invention recited in the claim13is featured by (i) an electric motor; (ii) a rotating device having a rotating shaft; and (iii) the rotating shaft of the rotating device being rotatably supported with a support wall mounted on a case, (iv) wherein under a status the support wall being interposed between a stator of the electric motor and the case, both the stator and the support wall are fastened to the case by bolts.

According to the invention recited in the claim12, since the spacer is integrally formed with the support wall, fixing the support wall to the case enables the spacer to be fixed to the case at the same time. Thus, no need arises for a structure to be provided for separately fixing the spacer to the case. This results in capability of preventing the drive apparatus from increasing in size.

According to the invention recited in the claim13, the support wall, intervening between the case and the stator of the electric motor, functions as the spacer between the stator of the electric motor and the case. Thus, no need arises for separately providing the spacer, enabling the drive apparatus to be prevented from increasing in size by an extent equivalent to a space for the spacer to be mounted.

Preferably, as the invention recited in the claim14, the rotating device is a gear device having a gear and a gear shaft. More preferably, as the invention recited in the claim15, the gear device has a plurality of planetary gear units.

Preferably, the rotary shaft of the rotating device is rotatably supported with the support wall; and as recited in the claim16, the electric motor also has a rotor rotatably supported with the support wall.

Preferably, as the invention recited in the claim17, the gear shaft of the gear device has one end supported with the support wall and the other end supported with a rotor support shaft of the electric motor.

EXPLANATION OF REFERENCES

10: drive apparatus for vehicle12: case12a: first case (second case)12b: second case16: power distribution mechanism (first gear device)20: step-variable automatic transmission (second gear device)26,28,30: planetary gear unit70: first unit (first power transmitting portion)72: partition wall (wall member)100: second unit (second power transmitting portion)104: input shaft (of automatic transmission)106: first support wall106c: outer peripheral cylinder (spacer)112: second stator114: second rotor116: second rotor support shaft118: bolt122: second support wall122b: recess122c: outer periphery124: boltM1: first electric motorM2: second electric motor

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be explained with reference to attaching drawings.FIG. 1is a skeleton view explaining a drive apparatus10for a hybrid vehicle according to one embodiment of the present invention. The drive apparatus10includes a drive apparatus input shaft14, a power distribution mechanism16, an automatic transmission20and a drive apparatus output shaft22all coaxially disposed in a transmission case12(hereinafter briefly referred to as “case12”) as a non-rotatable member fixed to a vehicle body. The drive apparatus input shaft14as an input rotation member is fixed to the case12. The power distribution mechanism16is connected to the input shaft14directly or indirectly via a pulsation absorbing damper (vibration damping device) not shown.

The automatic transmission20of a step-variable type is disposed between the distribution mechanism16and drive apparatus output shaft22to be connected thereto in series. The drive apparatus output shaft22as an output rotation member is connected to the automatic transmission20. In the present embodiment, the power distribution mechanism16and the step-variable automatic transmission20respectively correspond to the claimed first gear device and the second gear device. In a second embodiment, the above automatic transmission20corresponds to the claimed gear device i.e., the rotating device.

This drive apparatus10is suitably used for a transverse FR vehicle (front-engine, rear-drive vehicle), and is disposed as shown inFIG. 7between a drive power source in the form of an engine8and a pair of drive wheels38, to transmit a vehicle drive force to the pair of drive wheels38through a differential gear device36(final speed reduction gear) and a pair of drive axles. It is noted that a lower half of the drive apparatus10constructed symmetrically with respect to its axis, is omitted inFIG. 1.

The power distribution mechanism16is a mechanical mechanism synthesizing or distributing the output of the engine8input to the drive apparatus input shaft14. That is, it distributes the output of the engine8to the first electric motor M1and the transmitting member18, and synthesizes the outputs of the engine8and the first electric motor M1to output it to the transmitting member18. The second electric motor M2is rotatable integral with the transmitting member18. In the present embodiment, the first electric motor M1and the second electric motor M2are a so-called motor/generator also functioning as an electric generator. The first electric motor M1should function at least as an electric generator to generate an electric energy while generating a reaction force, and the second electric motor M2should function at least as an electric motor to generate a drive force of the vehicle.

The power distribution mechanism16includes a first planetary gear unit24of single pinion type having a gear ratio ρ1of about 0.418, for example, a switching clutch C0and a switching brake B0. The first planetary gear unit24has as rotating elements a first sun gear S1, a first planetary gear P1, a first carrier CA1supporting the first planetary gear P1to be rotatable about its axis and about the axis of the first sun gear S1, and a first ring gear R1meshing with the first sun gear S1through the first planetary gear P1. Representing the numbers of teeth of the first sun gear S1and the first ring gear R1by ZS1and ZR1, respectively, the above gear ratio ρ1is represented by ZS1/ZR1.

In the power distribution mechanism16, the first carrier CA1is connected to the drive apparatus input shaft14, i.e., to the engine8, the first sun gear S1is connected to the first electric motor M1, and the first ring gear R1is connected to the transmitting member18. The switching brake B0is disposed between the first sun gear S1and the casing12, and the switching clutch C0is disposed between the first sun gear S1and the first carrier CA1. Upon release of the switching clutch C0and brake B0, the first sun gear S1, first carrier CA1and first ring gear R1are placed in a differential state to be rotatable relative to each other, to perform a differential function. Thus, the output of the engine8is distributed to the first electric motor M1and the transmitting member18, a part of the output distributed to the first electric motor M1is used to generate power i.e, electricity thereat. The second electric motor M2is driven for rotation by en electric energy generated at the first electric motor M1or en electric energy stored. Accordingly, the power distribution mechanism16is placed in for example the continuously variable shifting state, in which the rotating speed of the transmitting member18changes continuously, irrespective of the rotating speed of the engine8.

That is, the power distribution mechanism16is placed in the differential state in which a speed ratio γ0(rotating speed of the driving device input shaft14/rotating speed of the transmitting member18) electrically changes from a minimum value γ0min to a maximum value γ0max. For example it is placed in the differential state, for example in the continuously variable shifting state, to function as an electrically continuously variable transmission of which the speed ratio γ0continuously varies from the minimum value γ0min to the maximum value γ0max.

In this state, during the vehicle running by the output of the engine8, when the first sun gear S1and the first carrier CA1are engaged integrally by engagement of the switching clutch C0, the rotary elements of the first planetary gear unit24including the first sun gear S1, first carrier CA1and first ring gear R1are placed in a locked state or a non-differential state to be rotatable as a unit. Thus, the rotating speeds of the engine8and the transmitting member18are coincided with each other, so that the power distribution mechanism16is placed in a fixed shifting state functioning as the transmission having a fixed speed ratio γ0equal to 1.

Then, by engagement of the switching brake B0instead of the switching clutch C0, the power distribution mechanism16is placed in a locked state or non-differential state in which the first sun gear S1is placed in a non-rotatable state, the rotating speed of the first ring gear R1is made higher than that of the first carrier CA1, so that the power distribution mechanism16is placed in the fixed shifting state functioning as a speed-increasing transmission having a fixed speed ratio γ0smaller than 1, for example, about 0.7.

In the present embodiment described above, the switching clutch C0and brake B0selectively place the first planetary gear unit24in the differential state and in the locked state, functioning as a differential limiting device which limits or restricts the differential operation of the rotary elements. That is, in the differential state (continuously variable state), the first planetary gear unit24functions as the electrically controlled continuously variable transmission of which the shifting ratio can be continuously varied. In the locked state or the fixed shifting state, the first planetary gear unit24is inhibited its continuously variable shifting operation and impossible to function as the electrically controlled continuously variable transmission, being locked its shifting ratio variation. Thus, in the locked state, the first planetary gear unit24operates as the transmission which has the single gear position or multiple gear positions.

The automatic transmission20includes plural planetary gear units, that is a single-pinion type second planetary gear unit26, a single-pinion type third planetary gear unit28and a single-pinion type fourth planetary gear unit30. The second planetary gear unit26includes a second sun gear S2, a second planetary gear P2, a second carrier CA2supporting the second planetary gear P2to be rotatable about its axis and about the axis of the second sun gear S2, and a second ring gear R2meshing with the second sun gear S2through the second planetary gear P2, having for example a gear ratio ρ2of about 0.562.

The third planetary gear unit28includes a third sun gear S3, a third planetary gear P3, a third carrier CA3supporting the third planetary gear P3to be rotatable about its axis and about the axis of the third sun gear S3, and a third ring gear R3meshing with the third sun gear S3through the third planetary gear P3, having for example a gear ratio ρ3of about 0.425. The fourth planetary gear unit30includes a fourth sun gear S4, a fourth planetary gear P4, a fourth carrier CA4supporting the fourth planetary gear P4to be rotatable about its axis and about the axis of the fourth sun gear S4, and the fourth ring gear R4meshing with the fourth sun gear S4through the fourth planetary gear P4, having a gear ratio ρ4of about 0.421.

Representing the numbers of teeth of the second sun gear S2, second ring gear R2, third sun gear S3, third ring gear R3, fourth sun gear S4and fourth ring gear R4by ZS2, ZR2, ZS3, ZR3, ZS4and ZR4, respectively, the above gear ratios ρ2, ρ3and ρ4are represented by ZS2/ZR2, ZS3/ZR3and ZS4/ZR4, respectively.

In the automatic transmission20, the second sun gear S2and the third sun gear S3integrally fixed to each other as a unit are selectively connected to the transmitting member18through a second clutch C2, and are selectively fixed to the casing12through a first brake B1. The second carrier CA2is selectively connected to the casing12through the second brake B2, and the fourth ring gear R4is selectively fixed to the transmission casing12through a third brake B3. The second ring gear R2, third carrier CA3and fourth carrier CA4integrally fixed to each other are fixed to the output shaft22. The third ring gear R3and the fourth sun gear S4integrally fixed to each other are selectively connected to the transmitting member18through a first clutch C1.

The switching clutch C0, the first clutch C1, the second clutch C2, the switching brake B0, the first brake B1, the second brake B2and the third brake B3are hydraulic-type frictionally coupling devices conventionally used in the vehicular automatic transmission. The frictionally coupling device includes a wet-type multiple-disc clutch in which a plurality of friction plates superposed on each other are forced against each other by a hydraulic actuator, or a band brake in which a rotary drum and one band or two bands wound on an outer circumferential surface thereof is tightened at one end by a hydraulic actuator.

In the drive apparatus10thus constructed, as shown in an operation Table ofFIG. 2, one of a first-gear position (first-speed position) through a fifth-gear position (fifth-speed position), a reverse-gear position (rear-drive position) and a neural position is selectively established by engagement of the switching clutch C0, the first clutch C1, the second clutch C2, the switching brake B0, the first brake B1, the second brake B2and the third brake B3. Those positions have respective speed ratios γ (input shaft speed NIN/output shaft speed NOUT) which change as geometric series.

In particular, in this embodiment, owing to provision of the switching clutch C0and brake B0, the power distribution mechanism16can be selectively placed, in addition to the continuously-variable shifting state operable as the continuously variable transmission, in the fixed shifting state operable as the transmission of the single step or multiple steps having one or not less than two kinds of shifting ratio. In the drive apparatus10, the step-variable transmission is constituted by the automatic transmission20and the power distribution mechanism16placed in the fixed shifting state engagement of the switching clutch C0or the switching brake B0. Further, the continuously-variable transmission is constituted by the automatic transmission20and the power distribution mechanism16placed in the continuously-variable shifting state, with none of the switching clutch C0and brake B0being engaged.

For example, when the drive apparatus10functions as the step-variable transmission, for example, as shown inFIG. 2, engagement of the switching clutch C0, the first clutch C1and the third brake B3establish the first-gear position having the highest speed ratio γ1of about 3.357, for example, and engagement of the switching clutch C0, the first clutch C1and the second brake B2establish the second-gear position having the speed ratio γ2of about 2.180, for example, which is lower than the speed ratio γ1. Further, engagement of the switching clutch C0, first clutch C1and first brake B1establish the third-gear position having the speed ratio γ3of about 1.424, for example, which is lower than the speed ratio γ2, and engagement of the switching clutch C0, first clutch C1and second clutch C2establish the fourth-gear position having the speed ratio γ4of about 1.000, for example, which is lower than the speed ratio γ3.

Engagement of the first clutch C1, second clutch C2and switching brake B0establishes the fifth-gear position having the speed ratio γ5of about 0.705, for example, which is smaller than the speed ratio γ4. Further, engagement of the second clutch C2and the third brake B3establishes the reverse-gear position having the speed ratio γR of about 3.209, for example, which positions between the speed ratios γ1and γ2. The neutral position N is established by engaging only the switching clutch C0.

However, when the drive apparatus10functions as the continuously-variable transmission, as shown inFIG. 2, the switching clutch C0and the switching brake B0are both released. With this, the power distribution mechanism16functions as the continuously-variable transmission, while the automatic transmission20connected in series thereto functions as the step-variable transmission. The rotating speed to be input to the automatic transmission20placed in one of the first-gear, second-gear, third-gear and fourth-gear positions, that is the rotating speed of the transmitting member18is continuously changed so that the continuous shifting ratio width can be obtained for each of the gear positions. Accordingly, since the speed ratio of the automatic transmission20is continuously variable across the adjacent gear positions, the overall speed ratio γT of the drive apparatus10is continuously variable.

FIG. 3shows a collinear chart representing by straight lines a relation among the rotating speeds of the rotary elements different in each of the gear positions of the drive apparatus10. The drive apparatus10is constituted by the power distribution mechanism16functioning as the continuously-variable shifting portion or first shifting portion, and the automatic transmission20functioning as the step-variable shifting portion or second shifting portion. The collinear chart ofFIG. 3is a rectangular two-dimensional coordinate system in which the gear ratios ρ of the planetary gear units24,26,28and30are taken along the horizontal axis, while the relative rotating speeds of the rotary elements are taken along the vertical axis. A lower one X1of three horizontal lines indicates the rotating speed of 0, and an upper one X2indicates the rotating speed of 1.0, that is, an operating speed NEof the engine8connected to the driving device input shaft14. The horizontal line XG indicates the rotating speed of the transmitting member18.

Among three vertical lines Y1, Y2and Y3corresponding to the three elements of the power distribution mechanism16, respectively represent from the left the relative rotating speeds of a second rotary element (second element) RE2in the form of the first sun gear S1, a first rotary element (first element) RE1in the form of the first carrier CA1, and a third rotary element (third element) RE3in the form of the first ring gear R1. The distances between the adjacent ones of the vertical lines Y1, Y2and Y3are determined corresponding to the gear ratio ρ1of the first planetary gear unit24. That is, when the distance between the vertical lines Y1and Y2is set to “1”, the distance between the vertical lines Y2and Y3corresponds to the gear ratio ρ1.

Further, five vertical lines Y4, Y5, Y6, Y7and Y8corresponding to the automatic transmission20respectively represent from the left the relative rotating speeds of a fourth rotary element (fourth element) RE4, a fifth rotary element (fifth element) RE5, a sixth rotary element (sixth element) RE6, a seventh rotary element (seventh element) RE7, and an eighth rotary element (eighth element) RE8. The fourth rotary element RE4has a form of the second and third sun gears S2, S3integrally fixed to each other, the fifth rotary element RE5has a form of the second carrier CA2, and the sixth rotary element RE6has a form of the fourth ring gear R4. The seventh rotary element RE7has a form of the second ring gear R2and third and fourth carriers CA3, CA4integrally fixed to each other, and the eighth rotary element RE8has a form of the third ring gear R3and fourth sun gear S4integrally fixed to each other.

The distances between the adjacent ones of the vertical lines Y4-Y8are determined by the gear ratios ρ2, ρ3and ρ4of the second, third and fourth planetary gear units26,28and30. That is, as shown inFIG. 3, for each of the second, third and fourth planetary gear units26,28and30, the distances between the sun gear and carrier corresponds to “1”, and the distances between the carrier and ring gear corresponds to the gear ratio ρ.

Expressing by the collinear chart ofFIG. 3, the drive apparatus10of this embodiment is, in the power distribution mechanism (continuously-variable shifting portion)16, arranged such that the first rotary element RE1(the first carrier CA1), which is one of the three rotary elements of the first planetary gear unit24, is fixed to the drive device input shaft14, and selectively connected to the first sun gear S1as another rotary element through the switching clutch C0. The second rotary element RE2(the first sun gear S1) as another rotary element is fixed to the first electric motor M1and selectively fixed to the casing12through the switching brake B0. The third rotary element RE3(the first ring gear R1) as still another rotary element is fixed to the transmitting member18and the second electric motor M2.

Thus, a rotation of the drive device input shaft14is transmitted (input) to the automatic transmission (step-variable transmission portion)20through the transmitting member18. An inclined straight line L0which passes an intersection point between the lines Y2and X2represents a relation between the rotating speeds of the first sun gear S1and the first ring gear R1.

FIGS. 4 and 5are figures correspond to a part of the power distribution mechanism16of the collinear chart ofFIG. 3.FIG. 4shows one example of an operating state of the power distribution mechanism16placed in the continuously-variable shifting state with of the switching clutch C0and the switching brake B0held in the released state. The rotating speed of the first sun gear S1represented by the intersection point between the straight line L0and a vertical line Y1is raised or lowered by controlling a reaction force resulted from a power generation at first electric motor M1, so that the rotating speed of the first ring gear R1represented by the intersection point between the lines L0and Y3is lowered or raised.

FIG. 5shows one example of a state of the power distribution mechanism16placed in the fixed shifting state with of the switching clutch C0held in the engaged state. By connection of the first sun gear S1and the first carrier CA1the three rotary elements rotate as a unit, the line L0being aligned with the horizontal line X2, which results in that the transmitting member18is rotated at the same speed as the engine speed NE. When rotation of the transmitting member18is stopped by engagement of the switching brake B0, the rotating speed of the first ring gear R1represented by an intersection point between the inclined straight line L0and vertical line Y3, that is the rotation of the transmitting member18is made higher than the engine speed NEand transmitted to the automatic transmission20.

In the automatic transmission20, the fourth rotary element RE4is selectively connected to the transmitting member18through the second clutch C2and selectively fixed to the casing12through the first brake B1, the fifth rotary element RE5is selectively fixed to the casing12through the second brake B2, and the sixth rotary element RE6is selectively fixed to the casing12through the third brake B3. The seventh rotary element RE7is fixed to the drive apparatus output shaft22, and the eighth rotary element RE8is selectively connected to the transmitting member18through the first clutch C1.

As shown inFIG. 3, in the automatic transmission20, upon engagement of the first clutch C1and the third brake B3, the rotating speed of the drive apparatus output shaft22in the first-speed position is represented by an intersection point between the inclined linear line L1and the vertical line Y7. Here, the inclined straight line L1passes an intersection point between the vertical line Y8indicative of the rotating speed of the eighth rotary element RE8and the horizontal line X2, and an intersection point between the vertical line Y6indicative of the rotating speed of the sixth rotary element RE6and the horizontal line X1.

Similarly, the rotating speed of the drive apparatus output shaft22in the second-speed position is represented by an intersection point between an inclined straight line L2determined by engagement of the first clutch C1and second brake B2, and the vertical line Y7indicative of the rotating speed of the seventh rotary element RE7fixed to the drive apparatus output shaft22. The rotating speed of the drive apparatus output shaft22in the third-speed position is represented by an intersection point between an inclined straight line L3determined by engagement of the first clutch C1and first brake B1, and the vertical line Y7indicative of the rotating speed of the seventh rotary element RE7fixed to the drive apparatus output shaft22. The rotating speed of the drive apparatus output shaft22in the fourth-speed position is represented by an intersection point between a horizontal line L4determined by engagement of the first clutch C1and second clutch C2, and the vertical line Y7indicative of the rotating speed of the seventh rotary element RE7fixed to the drive apparatus output shaft22.

In the first-speed through fourth-speed positions, as result of engagement of the switching clutch C0, power from the power distribution mechanism16is input to the eighth rotary element RE8with the rotating speed the same as that of the engine speed NE. However, when the switching clutch B0engages instead of the switching clutch C0, since power from the power distribution mechanism16is input to the eighth rotary element RE8with a speed higher than the engine speed NE, the rotating speed of the drive apparatus output shaft22in the fifth-speed position is represented by an intersection point between a horizontal line L5and the vertical line Y7. Here, the horizontal line L5is determined by engagement of the first clutch C1, second clutch C2and switching brake B0, and the vertical line Y7indicates the rotating speed of the seventh rotary element RE7fixed to the output shaft22. The rotating speed of the drive apparatus output shaft22in the reverse-gear position R is represented by an intersection point between an inclined straight line LR determined by engagement of the second clutch C2and third brake B3, and the vertical line Y7indicative of the rotating speed of the seventh rotary element RE7fixed to the drive apparatus output shaft22.

FIG. 6illustrates signals input to an electronic control device40and signals output therefrom to control the drive apparatus10. This electronic control device40includes a so-called microcomputer incorporating a CPU, a ROM, a RAM and an input/output interface. By performing signal processing according to programs stored in the ROM utilizing a temporary data storage function of the ROM, it implements hybrid drive controls of the engine8and electric motors M1and M2, and drive controls such as shifting controls of the automatic transmission20.

To the electronic control device40, from various sensors and switches shown inFIG. 6, various signals are inputted, which include a signal indicative of a temperature of cooling water of the engine, a signal indicative of a selected operating position of a shift lever, a signal indicative of the operating speed NEof the engine8, a signal indicative of a set value of gear ratio row, a signal indicative of a command for M mode (motor drive mode), a signal indicative of an operated state of an air conditioner, a signal indicative of a vehicle speed corresponding to the rotating speed of the drive apparatus output shaft22, a signal indicative of a working oil temperature of the automatic transmission20, a signal indicative of an operated state of a side brake, a signal indicative of an operated state of a foot brake, a signal indicative of a catalyst temperature, a signal indicative of an opened amount of an accelerator pedal, a signal indicative of a cam angle, a signal indicative of a snow drive mode, a signal indicative of a longitudinal acceleration value of the vehicle, and a signal indicative of an auto-cruising drive mode.

Also inputted are a signal indicative of a vehicle weight, a signal indicative of wheel speed of each drive wheel, a signal indicative of operation of a step-variable switch for changing the power transmitting mechanism16to the fixed shifting state so that the drive apparatus10functions as the step-variable transmission, a signal indicative of operation of a continuous-variable switch for changing the power transmitting mechanism16to the continuously-variable shifting state so that the drive apparatus10functions as the continuously-variable transmission, a signal indicative of the rotating speed NM1of the first electric motor M1, and a signal indicative of the rotating speed NM2of the second electric motor M2.

From the electronic control device40, various signals are outputted, which include a signal to drive a throttle actuator for controlling an opening of a throttle valve, a signal to adjust a supercharger pressure; a signal to operate the electric air conditioner, a signal for controlling an ignition timing of the engine8, signals to operate the electric motors M1and M2, a signal to operate a shift-range indicator for indicating the selected operating position of the shift lever, a signal to operate a gear-ratio indicator for indicating the gear ratio, a signal to operate a snow-mode indicator for indicating the selection of the snow drive mode, a signal to operate an ABS actuator for anti-lock braking of the wheels, and a signal to operate an M-mode indicator for indicating the selection of the M-mode.

Also output are signals to operate solenoid-operated valves incorporated in a hydraulic control unit42provided to control the hydraulic actuators of the hydraulically operated frictional coupling devices of the power distribution mechanism16and the automatic transmission20, a signal to operate an electric oil pump used as a hydraulic pressure source for the hydraulic control unit42, a signal to drive an electric heater, and a signal to be applied to a cruise-control computer.

FIG. 7is a functional block diagram explaining a main control functions performed by the electronic control device40. Switching control means50determines whether the vehicle condition is the continuously variable shifting region for placing the drive apparatus10in the continuously-variable shifting state, or in a step-variable shifting region for placing the same in the step-variable shifting state, based on a relation shown inFIG. 8orFIG. 9and stored in advance. In using the relation (shifting map) shown inFIG. 8, the vehicle condition is determined based on the actual operating speed NEof the engine8and a drive-force-related value related to the drive force of the hybrid vehicle such as an output torque TEof the engine.

In the relation shown inFIG. 8, three regions of a high-torque region, a high-rotation region, and a high-output region are set as the step-variable shifting region. In the high-torque region (high-output running region) the output torque TEof the engine8is not smaller than a predetermined value TE1, in the high-rotation region (high-vehicle speed region) the engine speed NEis not lower than a predetermined value NE1, that is the vehicle speed which is one of the vehicle condition determined by the rotating speed of the engine and the total shifting ratio γT is not less than the predetermined value, and in the high-output region the engine output determined by the output torque TEand speed NEof the engine8is not smaller than a predetermined value.

Accordingly, the step-variable shifting control is effected for the comparatively high torque, the comparatively high peed or the comparatively high output of the engine8, so that the rotating speed of the engine8rhythmically changes in response to change of the rotating speed NEof the engine i.e., shifting upon up-shifting. In other words, in the high output running, in view of preference of the driver's requirement to the drive force than that to the fuel economy, the drive apparatus10is switched to the step-variable shifting state (fixed shifting state) than the continuously-variable shifting state. With this, the driver can enjoy the rhythmical change of the rotating speed NEof the engine.

To the contrary, in the normal output region of the engine, that is in the comparatively low torque, the comparatively low peed or the comparatively low output of the engine8, the continuously-variable shifting control is effected. A boundary line inFIG. 8between the step-variable shifting region and the continuously-variable shifting region, corresponds to a high vehicle speed determination line which is series of high vehicle speed determination points, and a low vehicle speed determination line which is series of low vehicle speed determination points.

On the other hand, in using the relation shown inFIG. 9, the above determination is performed based on the actual vehicle speed V and the output torque TOUTwhich is the drive-force-related value. InFIG. 9, a broken line represents a determination vehicle speed V1and a determination output torque T1for defining the predetermined condition to switch the continuously-variable shifting to the step-variable shifting. A two-chain dot line represents the condition for changing the step-variable shifting to the continuously-variable shifting. As apparent, hysteresis is provided between the step-variable shifting region and the continuously-variable shifting region. InFIG. 9, a region located at a lower output torque side and a lower vehicle speed side than the boundary line represented by a thick line is a motor running region for the vehicle to run by the drive force of the electric motor. InFIG. 9, shifting lines with the vehicle speed V and the output torque Tout as the parameter are shown as well.

The switching control means50, determining the step-variable shifting region, outputs command to the hybrid control means52to inhibit the hybrid control or continuously-variable shifting control thereby, and commands to the step-variable shifting control means54to perform the predetermined shifting operation. The step-variable shifting control means54, upon determination withFIG. 8, performs the automatic shifting control in accordance with the shifting diagram (not shown) memorized in advance. It performs the automatic shifting control, upon determination withFIG. 9, in accordance with the shifting diagram shown therein.

FIG. 2shows the operation combinations of the hydraulically operated frictional coupling devices, that is the clutches C0, C1, C2, and the brakes B0, B1, B2and B3, selected in the shifting control. In one of the first-speed position through the fourth-speed position of this step-variable automatic shifting control mode, the power distribution mechanism16functions as an auxiliary transmission having a fixed speed ratio γ0of 1, with engagement of the switching clutch C0. In fifth-speed position, by engagement of the switching brake B0instead of the switching clutch C0, the power distribution mechanism16functions as an auxiliary transmission having a fixed speed ratio γ0of about 0.7. Thus, in the step-variable automatic shifting control mode, the drive apparatus10which includes the power distribution mechanism16functioning as the auxiliary transmission, and the automatic transmission20, functions as a so-called automatic transmission as a whole.

The above drive-force-related value is a parameter corresponding to the drive force of the vehicle, which may be the drive torque or the drive force at the drive wheel. In addition, it may be an output torque TOUTof the automatic transmission20, an engine output torque TE, an acceleration value of the vehicle; an actual value such as the engine output torque TEcalculated based on the operating angle of the accelerator pedal or the opening angle of the throttle valve (or intake air quantity, air/fuel ratio or amount of fuel injection) and the engine speed NE; or an estimated value such as the engine output torque TEor required vehicle drive force calculated based on the amount of operation of the accelerator pedal by the vehicle operator or the operating angle of the throttle valve. The vehicle drive torque may be calculated based on not only the output torque TOUT, etc., but also the ratio of a differential gear device of and the radius of the drive wheels38, or may be directly detected by a torque sensor or the like. This is true for each of torques mentioned above.

On the other hand, when determining the continuously-variable control region, the switching control means50outputs command to the hydraulic control circuit42to release the switching clutch C0and the switching brake B0for placing the power distribution mechanism16in the continuously-variable shifting state. In addition, the switching control means50outputs, simultaneously with the above command to the hydraulic control circuit42for releasing the switching clutch C0and the switching brake B0, signal to the hybrid control means52for permitting the hybrid control, and to the step-variable shifting control means54one of following two signals. One is the signal to hold the automatic transmission20in the gear position upon the continuously-variable shifting set advance, and other is to permit an automatic shifting according to the shifting diagram memorized in advance. In the latter case, the variable-step shifting control means54effects the automatic shifting by suitably selecting the combinations of the clutches and brakes shown in the operation Table ofFIG. 2, except the combination of engagement of both the switching clutch C0and brake B0.

Thus, by functions of the power distribution mechanism16as the continuously-variable transmission, and the automatic transmission connected in series thereto as the step-variable transmission, the drive force of suitable magnitude can be obtained. In addition, as described above, the rotating speed to be input to the automatic transmission20placed in one of the first-gear, second-gear, third-gear and fourth-gear positions, that is the rotating speed of the transmitting member18is continuously changed so that the continuous shifting ratio width can be obtained for each of the gear positions. Accordingly, since the speed ratio of the automatic transmission20is continuously variable across the adjacent gear positions, the overall speed ratio γT of the drive apparatus10is continuously variable.

The hybrid control means52controls the engine8to be operated in the high efficiency region, and controls the first electric motor M1and the second electric motor M2to establish an optimum proportion of the drive forces of the engine8, the first electric motor M1and/or the second electric motor M2. For instance, the hybrid control means52calculates the output as required by the driver at the current running speed of the vehicle based on the operating amount of the accelerator pedal and the vehicle running speed, and calculates a required drive force based on the required output calculated and a required charge amount by the first electric motor M1. Based on the required drive force calculated, the hybrid control means52calculates desired rotating speed NEand total output of the engine8, and controls the actual output of the engine8and the generated electricity amount by the first electric motor M1, according to the calculated desired rotating speed and total output of the engine. The hybrid control means52effects the above hybrid control with taking account of the gear position of the automatic transmission20currently selected, or commands the shifting of the automatic transmission20to improve the fuel economy of the engine.

In such the hybrid control, the power distribution mechanism16is controlled to function as the electrically controlled continuously-variable transmission, for the optimum coordination of the rotating speed NEfor efficient operation of the engine8, and the rotating speed of the transmitting member18determined by both the vehicle speed and the selected gear position of the automatic transmission20. That is, the hybrid control means52determines a target value of the overall speed ratio γT of the drive apparatus10so that the engine8is operated according to a highest-fuel-economy curve memorized in advance that satisfies both the drivability and the highest fuel economy of the engine8upon running in the continuously-variable shifting. The hybrid control means52controls the shifting ratio γ0of the power distribution mechanism16to obtain the target value of the overall speed ratio γT, so that the overall speed ratio γT can be controlled within a predetermined range, for example, between 13 and 0.5.

In the hybrid control, the hybrid control means52controls an inverter58such that the electric energy generated by the first electric motor M1is supplied to an electric-energy storage device60and the second electric motor M2through it. Therefore, a main part of the drive force produced at the engine8is mechanically transmitted to the transmitting member18, while the rest of the drive force is consumed by the first electric motor M1to be converted into the electric energy, being supplied through the inverter58to the second electric motor M2, or subsequently consumed by the first electric motor M1. The drive force produced by operation of the second electric motor M2or first electric motor M1with the electric energy is transmitted to the transmitting member18.

Components associated with from generation to consumption of the electric energy by the second electric motor M2constructs the electric path for converting the power generated at the engine8to the electric energy and then convert the electric energy to the mechanical energy. Further, the hybrid control means52performs the motor running in which the vehicle is started and driven by the electric CVT function of the power distribution mechanism16, irrespective of the stopped state or the idling state of the engine8.

In the normal output region of the engine where the vehicle runs in the lower/medium speed and in the lower/medium output, the power distribution mechanism16is placed in the continuously-variable shifting state by the switching control means50, the hybrid control means52and the step-variable shifting control means54to secure the fuel economy quality of the vehicle. In the high speed running or in the high rotation speed region of the engine8, the power distribution mechanism16is placed in the fixed shifting state by the same to transmit the output of the engine8mainly through the mechanical power transmitting path to the drive wheel38. Thus, the loss occurred upon conversion between power and electricity is suppressed to improve the fuel economy.

The power distribution mechanism16is placed in the fixed shifting state in the high output region of the engine, and it operates in the continuously-variable shifting state for the low/medium speed running and the low/medium output running of the vehicle. Accordingly, the maximum value of the electric energy to be generated by the first electric motor M1, that is, the electric energy to be transmitted by the same can be made small. In other words, the electric reaction force to be secured by the first electric motor M1can be made small, so that the first electric motor M1itself, the second electric motor M2, and the drive apparatus10including them can be further compactified.

FIG. 10shows an example of a shifting device46which is a manually operable shifting device. It is disposed laterally adjacent to an driver seat, for example, and has a shift lever48to be manually operated to select one of a plurality of gear positions including a parking position P, a reverse-drive position R, a neutral position N, an automatic forward-drive shifting position D, and a manual forward-drive shifting position M. Upon the parking position P, the drive apparatus10i.e., the automatic transmission20is placed in a neutral state where the power transmitting path is disconnected with release of the switching clutch C0and brake B0, and simultaneously the drive apparatus output shaft22of the automatic transmission20is placed in the locked state. Upon the reverse-drive position R, the vehicle is driven in the rearward direction, and upon the neutral position N, the drive apparatus10is placed in the neutral state.

The parking position P and the neutral position N are non-running positions selected upon non-running of the vehicle, while the reverse-drive position R and the automatic and manual forward-drive shifting positions D and M are driving positions selected upon running of the vehicle. The automatic forward-drive shifting position D provides a highest-speed position, and positions “4” through “L” selectable therein are engine-braking positions for obtaining an engine brake.

The manual forward-drive shifting position M is located at the same position as the automatic forward-drive shifting position D in the vehicle longitudinal direction, and is spaced from or adjacent to the automatic forward-drive shifting position D in the vehicle lateral direction. The shift lever48is operated to the manual forward-drive shifting position M, for manually selecting one of the positions “D” through “L”. Described in detail, the shift lever48is movable from the manual forward-drive shifting position M to a shift-up position “+” and a shift-down position “−” spaced from each other in the longitudinal direction. Each movement of shift lever48to the shift-up position “+” or the shift-down position “−”, the currently selected position is changed to any of the positions “D” through “L” position.

The five positions “D” through “L” in the “M” position are plural kinds of shifting positions of which the total shifting ratios γT at the high-speed side (minimum side of the shifting ratio) are different in variable range of the total shifting ratio γT attainable by the automatic transmission20upon the automatic shifting control. They limit the shiftable range of the shifting position (gear position) so that the shifting positions at the maximum speed side attainable by shifting of the automatic transmission20are different. The shift lever48is biased by biasing means such as a spring to be automatically returned from the shift-up position “+” and shift-down position “−” back to the manual forward-drive shifting position M. The shifting device46is provided with shift-position sensors (not shown) to detect each shifted position of the shift lever48, position of the shift lever48and the number of the shift operation of the shift lever48at the manual forward-shifting position “M” are output to the electronic control device40.

For example, when the shift lever48is operated to the automatic forward-drive shifting position “D”, the switching control means50effects an automatic switching control of the drive apparatus10, the hybrid control means52effects the continuously-variable shifting control of the power distribution mechanism16, and the step-variable shifting control means54effects an automatic shifting control of the automatic transmission20. When placed in the step-variable shifting state for the step-variable shifting running, for example, shifting of the drive apparatus10is automatically controlled to select an appropriate one of the first-gear position through the fifth-gear position indicated inFIG. 2.

When placed in the continuously-variable shifting state for the continuously-variable shifting running, the overall speed ratio γT of the drive apparatus10is controlled to be continuously variable within the predetermined range, which is obtained by the shifting ratio width of the power distribution mechanism16continuously variable and one of the first-gear through fourth-gear positions of the automatic transmission20automatically controlled. The automatic forward-drive position “D” is a position selected to establish an automatic shifting mode (automatic mode) in which the drive apparatus10is automatically shifted.

When the shift lever48is operated to the manual forward-drive shifting position “M”, shifting of the drive apparatus10is automatically controlled by the switching control means50, hybrid control means52and step-variable shifting control means54, such that the overall speed ratio γT varies within a predetermined range which can be attainable by each shifting position of the drive apparatus10, not to exceed the shifting position or shifting ratio at the maximum side of the shifting range. When the drive apparatus10is placed in the step-variable shifting state, for example, shifting of the drive apparatus10is automatically controlled within the predetermined range of the overall speed ratio γT.

In the continuously-variable shifting state for the continuously-variable shifting running, the overall speed ratio γT of the drive apparatus10is controlled to be continuously variable within the predetermined range in each shifting position, which is obtained by the shifting ratio width of the power distribution mechanism16continuously variable, and one of the first-gear through fourth-gear positions of the automatic transmission20automatically controlled. The manual forward-drive position “M” is a position selected to establish a manually shifting mode (manual mode) in which the selectable gear positions of the drive apparatus10are manually selected.

FIG. 11is a sectional-view of the above drive apparatus10, andFIGS. 12 and 13are enlarged cross-sectional view of a first unit (first power transmitting portion)70and a second unit (second power transmitting portion)100, of the drive apparatus10.

As shown inFIG. 11, the case12comprises a first case12a(corresponding to a second case in the illustrated embodiment) acting as a case of a first unit70and a second case12aacting as a case of a second unit72. The first case12aaccommodates therein the first electric motor M1and the power distributing mechanism (that is, a first gear unit)16or the like and the second case12baccommodates therein the second electric motor M2and the automatic power transmission (that is, a second gear unit)20or the like.

As shown inFIG. 12, the first case12ahas a substantially tubular outer diametric shape with a part, accommodating therein the power distributing mechanism16, which has a substantially fixed outer diameter. Meanwhile, a part accommodating therein the first electric motor M1has an outer diameter that increases towards the engine8(leftward in the drawing). Further, the first case12ahas both ends opened in an axial direction, and a partition wall72integrally formed therewith in a part between the power distributing mechanism16and the first electric motor M1. The partition wall72has a vertical portion72aextending substantially perpendicular to the drive apparatus input shaft14and a tubular portion72bhaving one axial end connected to an inner peripheral end of the vertical portion72aand extending towards the first planetary gear unit24.

The tubular portion72bhas a central area formed with a through-bore73extending in an axial direction. Being partitioned with the partition wall72, the casing12is divided into a first accommodating compartment74facing the engine8to accommodate the first electric motor M1, and a second accommodating compartment76for accommodating the power distributing mechanism16. Accordingly, in the illustrated embodiment, the partition wall72functions as a wall member. In addition, the first electric motor M1is accommodated in the first accommodating compartment74from a left side in the drawing and the power distributing mechanism16is accommodated in the second accommodating compartment76from a right side in the drawing.

Further, the first case12ais formed with an annular protrusion78axially protruding towards the engine8in parallel to the drive apparatus input shaft14such that the first accommodating compartment74has substantially fixed diameter. A cover plate80is fixed to an outer circumferential edge of the protrusion78in abutting engagement therewith.

The first electric motor M1includes a first stator (stationary part)82, a first rotor (rotator)84and a first rotor support shaft (rotary shaft)86integrally formed with the first rotor84. The first rotor support shaft86has one end supported with the partition wall72on an inner circumferential periphery thereof via a bearing88, and the other end supported with the cover plate80by means of a bearing90. A sun gear shaft92, functioning as a power transmitting shaft for connecting the first electric motor M1and the first planetary gear unit24for power transmitting capability, is integrally formed with a first sun gear S1. It passes through the through-bore73of the partition wall72into an inner circumferential periphery of the first rotor support shaft86. The sun gear shaft92has one end, facing the first rotor support shaft86, which is coupled through a spline93to one end of the first rotor support shaft86in an area facing the partition wall72, for unitary rotations of the sun gear shaft92and the first rotor support shaft86.

On an inner periphery of the sun gear shaft92at a position radially inward the bearing88, an inner periphery of the first rotor support shaft86at a position radially inward the bearing90, and an inner periphery of the sun gear S1, a bush97, a bearing98and a bush99are provided, respectively. The drive apparatus input shaft14is supported with the first rotor support shaft86and the sun gear shaft92, via the bush97, the bearing98and the bush99on inner peripheries of the first rotor support shaft86and the sun gear shaft92in a center of axis of the first case12ato be rotatable relative to each other. Further, the drive apparatus input shaft14has one end integrally connected to the first carrier CA1. Thus, the drive apparatus input shaft14is integrally connected to the first carrier CA1to form an input shaft of the first planetary gear unit24.

The first ring gear R1of the first planetary gear unit24has one end, facing a second unit100, which has an inner periphery to which an annular plate94is fixed to be immovable in an axial direction and circumferential direction. The annular plate94extends perpendicular to an axis center of the drive apparatus input shaft14and has a central area formed with a bore. The first planetary gear unit24has an output shaft (that is, an output shaft of the power distributing mechanism16)96including a tubular shaft portion96aprotruding towards the second unit100, and a flange portion96bradially protruding from the shaft portion96aon a side closer to the first planetary gear unit24. The flange portion96bis joined to the annular plate94for unitary rotation therewith. Moreover, the shaft portion96ahas an inner circumferential periphery formed with spline teeth96c. The switching clutch C0is placed between the partition wall72and the first planetary gear unit24, and a switching brake B0is placed in a radially outward area of the first planetary gear unit24.

Next, the second unit100will be described. As shown inFIG. 11, the second case12bis opened on a side facing the first unit70and has a tapered shape that decreases in diameter (in outer and inner diameters) towards the drive apparatus output shaft22in a stepwise fashion. The automatic transmission20and the second electric motor M2are accommodated in the second case12bin sequence from a rear area (at a position closer to the drive apparatus output shaft22), formed in a small diameter, to the open side of the second case12b.

Moreover, the drive apparatus output shaft22, an intermediate shaft102of the automatic transmission20, and an input shaft104of the automatic transmission20are coaxially placed in the second case12bon an axis center of the second case12bin sequence from a rear area thereof to be rotatable relative to each other. The input shaft104has one end, closer to a rear area of the second case12b, which is placed in the vicinity of one end of the second electric motor M2and extends toward the open end of the second case12b. Though not shown inFIG. 11, moreover, the drive apparatus output shaft22is connected to the fourth carrier CA4of the fourth planetary gear unit30for unitary rotation therewith, and the intermediate shaft102is connected to the fourth sun gear S4of the fourth planetary gear unit30for unitary rotation therewith (seeFIG. 1).

As shown inFIG. 13representing a fragmentary enlarged view of the second unit100, the second case12bhas a first support wall106placed between the automatic transmission20and the second electric motor M2. The first support wall106is held in fitting engagement with the input shaft104on one end thereof in an area facing the drive apparatus output shaft22(on a right side in the drawing). The first support wall106includes a tubular portion106aaxially extending in coaxial relation with the input shaft104, a connecting portion106bhaving an inner peripheral end connected to the tubular portion106aon one end thereof in face of the second electric motor M2and extending radially outward, and an outer circumferential annular portion106chaving one axial end connected to an outer circumferential periphery of the connecting portion106band axially extending towards the second electric motor M2.

The first support wall106has an inside-down structure with the second case12b. That is, the outer circumferential annular portion106cof the first support wall106has an outer circumferential periphery held in abutting engagement with a first abutting surface108formed in the second case12bon an inner circumferential periphery thereof in parallel to the axis thereof. Under a situation where the outer circumferential annular portion106cis not fixed by bolts118, the outer circumferential periphery of the outer circumferential annular portion106cis made slidable on the first abutting surface108. Accordingly, the first support wall106can be fitted to the second case12bwith no need to be press fitted.

Further, the outer circumferential annular portion106chas one side surface, formed in opposition to the second electric motor M2, which is held in abutting contact with a first radial surface109formed on the second case102bto radially extend inward from one end, opposing to the second electric motor M2, of the first abutting surface108. Accordingly, by merely fitting the first support wall106to the second case12bso as to allow the outer circumferential periphery and the side surface of the outer circumferential annular portion106cto be brought into abutting contact with the first abutting surface108and the first radial surface109of the second case12b, respectively, the outer circumferential annular portion106ccan be positioned in its axial direction and radial direction with high precisions. The input shaft104has one end, facing the automatic transmission20, which is supported on the tubular portion106aof the first support wall106by means of a bearing111provided on an inner periphery of the tubular portion106aof the first support wall106to be rotatable relative thereto.

The second electric motor M2includes a second stator (stationary part)112, a second rotor (rotator)114and a second rotor shaft (rotary shaft)116integrally formed with the first rotor114. The second stator112and the first support wall106are fixed to the second case102bby means of bolts118axially extending through the second stator112and the outer circumferential annular portion106cof the first support wall106, and screwed into the second case12b. Moreover, the second rotor support shaft116has one end, facing the automatic transmission20, that is, one end facing the drive apparatus output shaft22, which is supported with the first support wall106by means of a bearing120whose outer circumferential periphery is held in abutting contact with an inner circumferential periphery of the tubular portion106aof the first support wall106.

A second support wall122is disposed on the open side of the second case12bin an area apart from the second electric motor M2, that is, in opposition to the first support wall106. The second support wall122also has an inside-down structure with the second case12b. That is, the second support wall122has an outer circumferential surface held in abutting contact with a second abutting surface123formed on an inner circumferential surface of the second case12bin an area closer to the open end of the second case12bthan the second abutting surface108and extending radially outward therefrom. In the unfixed state, the outer circumferential surface of the second support wall122is made slidable along the second abutting surface123.

Further, the second support wall122has a side wall, facing the second electric motor M2, whose outer circumferential end is held in abutting contact with a second radial surface125formed on the second case12bso as to extend radially inward from one end of the second abutting surface123in an area facing the second electric motor M2. Accordingly, by merely fitting the second support wall122to the second case12bsuch that its outer circumferential periphery and side surface are brought into abutting contact with the second abutting surface123and the second radial surface125of the second case12b, respectively, the second support wall122can be also positioned in its axial direction and radial direction with high precisions.

The second support wall122is fixed to the second case12bvia the bolts124and has a radial center formed with a bore126extending in an axial direction. The input shaft104extends towards the first unit70and has a protruding portion104aextending through the second rotor support shaft116and the bore126to protrude towards the first unit70. The protruding portion104a(that is, a leading end of the input shaft104) has an outer periphery formed with spline teeth104bin an area radially facing the bore126.

Further, the second support wall122includes a convexed portion122aaxially protruding towards the second rotor114in an area radially inward the second stator112, a concaved portion122bradially extending outward from the convexed portion122aand axially concaved towards the first unit70, that is, in opposition to the second electric motor M2, and an outer circumferential marginal portion122cconnected to an outer circumferential edge of an opening of the concaved portion122ballowing the bolts124to extend. The convexed portion122ahas an inner circumferential periphery with which a bearing128is held in abutting contact. Furthermore, the second stator112has a stator coil112athat is accommodated in the concaved portion122b.

The second rotor support shaft116has the other end, opposite to one end thereof supported with the first support wall106, which is supported with the second support wall122by means of the bearing128. Moreover, the other end, closer to the second support wall122, of the second rotor support shaft116supports the input shaft104via a bearing130placed radially inward the bearing128and is coupled to the input shaft104via a spline132formed on one end thereof in an area closer to the first support wall106such that the second rotor support shaft116is unitarily rotation with the input shaft104.

With the second unit100formed in such a structure, the relevant component parts are assembled in sequence starting from the component part accommodated in the second case12bat the rearmost area thereof. That is, the automatic transmission20is initially accommodated in the second case12b, to which the first support wall106and the second electric motor M2are accommodated in this order. Lastly, the second support wall12bis mounted to the second case12b, enabling the second unit100to be assembled. Upon completely assembling the first and second units70,100, respectively, the spline teeth96cof the output shaft96acting as a member of the second unit70, and the spline teeth104bof the input shaft104acting as a member of the second unit100, are coupled (in spline connection), thereby enabling the drive apparatus10to be assembled in a manner as shown inFIG. 11. In addition, the transmitting member18, shown inFIG. 1, includes the output shaft96and the input shaft104that are spline coupled to each other for unitary rotation.

In the illustrated embodiment, as set forth above, the automatic transmission20and the second electric motor M2are accommodated in one case (second case12b), and the input shaft104of the automatic power transmission20and the second rotor support shaft116of the second electric motor M2are supported with the first support wall106and second support wall122, respectively, which are mounted on the second case12b. Thus, the automatic transmission20and the second electric motor M2can be unitized as a power transmitting portion, resulting in an increase in assembling workability of the drive apparatus10.

In the illustrated embodiment, further, the first electric motor M1and the power distributing mechanism16form another unit (as a power transmitting portion), that is, the first unit70such that the drive apparatus10is structured with the two units70,100. Thus, upon assembling the two units70,100, respectively, merely coupling these component parts to each other enables the drive apparatus10to be assembled. This results in a further increase in assembling workability of the drive apparatus10.

In the illustrated embodiment, furthermore, the first unit70can be assembled such that the power distributing mechanism16is accommodated in the first case12aon one side thereof and the first electric motor M1is accommodated in the first case12aon the other side thereof, providing improved assembling workability.

In the illustrated embodiment, moreover, the first support wall106held in abutting contact on the outer circumferential surface thereof with the inner circumferential surface (first abutting surface108) of the second case12b, can be positioned in a radial direction with high precision. Moreover, the second support wall122also held in abutting contact with the inner circumferential surface (second abutting surface123) of the second case12b, can also be positioned in a radial direction with high precision. In addition, the second rotor support shaft116of the second electric motor M2having both ends supported with the first and second support walls106,122, respectively, can also be positioned in a radial direction with high precision.

Further, the input shaft104of the automatic power transmission20supported with the second rotor support shaft116and the first support wall106, can also be positioned in a radial direction with high precision. Consequently, this particularly provides an ease of performing the assembling work of the drive apparatus10for the input shaft104and the output shaft96of the power distributing mechanism16to be coupled to each other, while making it easy to perform the operations of the input shaft104and the output shaft96for unitary rotation.

In the illustrated embodiment, furthermore, since the stator coil112aof the second electric motor M2is accommodated in the concaved portion122bformed on the second support wall122in the axially concaved configuration, a space can be effectively utilized, enabling the drive apparatus10to be shortened in an axial length thereof.

Meanwhile, the second stator112is held in abutting contact with a side surface of the inner circumferential tubular portion106cof the first support wall106, that is, the inner circumferential tubular portion106cof the first support wall106intervenes between the second stator112and the case12, so that an axial position of the second stator112is fixed. Accordingly, the inner circumferential tubular portion106cof the first support wall106functions as a space between the second stator112and the case12and thus, the first support wall106can also be regarded as a structure having the space unitarily formed.

In addition, the second stator112and the first support wall106are fastened to the case12by means of bolts118axially extending through the inner circumferential tubular portion106cof the first support wall106and clenched to the case12.

The input shaft104, extending towards the first unit70(leftward in the drawing), passes through the second rotor support shaft116and the through-bore126to protrude into the first unit70. The input shaft104has the area, placed in opposition to the through-bore126, to which the output shaft96of the first planetary gear unit24is spline coupled. Moreover, the transmitting member18, shown inFIG. 1, includes the input shaft104and the output shaft96that are spline coupled to each other for unitary rotation.

In the illustrated embodiment, as set forth above, the spacer is unitarily formed with the first support wall106. Therefore, merely fixing the first support wall106to the case12enables the spacer of the second stator112to be fixed to the case12at the same time. Thus, no need arises for providing a discrete structure for separately fixing the spacer to the case12, making it possible to prevent the drive apparatus10from increasing in size.

In the illustrated embodiment, stated another way, the first support wall106intervening between the case12and the second stator112of the second electric motor M2functions as a spacer between the second stator112of the second electric motor M2and the case12. Thus, no need arises for separately providing a spacer, enabling the drive apparatus10to be prevented from increasing in size.

While the present invention has been described above with reference to the illustrated embodiment shown in the accompanying drawings, the present invention may be implemented in other modes.

For instance, in the illustrated embodiment, the drive apparatus10is structured to enable the power distribution mechanism16to be switched in the differential state and the non-differential state for the continuously variable shifting state functioning as the electrically continuously variable transmission and the step-variable shifting state functioning as the step-variable shifting transmission. However, the switching between the continuously variable shifting state and the step-variable shifting state is performed as one mode of placing the power distribution mechanism16in the differential state and the non-differential state. Even if, for instance, placed in the differential state, the power distribution mechanism16may be arranged to function as a step-variable transmission with the shifting speed ratio thereof made variable not in a continuous mode but in a stepwise mode. In other words, since the differential state/non-differential state and the continuously variable shifting state/step-variable shifting state of the drive apparatus10(the power distributing mechanism16) do not necessarily fall in a one-on-one correspondence, the drive apparatus10needs not necessarily formed in a structure to enable the switching between the step-variable shifting state and the continuously variable shifting state.

In the power distribution mechanisms16in the illustrated embodiments, the first carrier CA1is fixed to the engine8, and the first sun gear S1is fixed to the first electric motor M1, and the first ring gear R1is fixed to the transmitting member18. However, such connecting arrangement is not essential, and the engine8, first electric motor M1and the transmitting member18are fixed to respective ones of the three elements CA1, S1and R1of the first planetary gear set24.

Although the engine8is directly connected to the drive apparatus input shaft14in the illustrated embodiments, it may be operatively connected to the drive apparatus input shaft14through gears, a belt or the like, and need not be disposed coaxially therewith.

In the embodiments, the first electric motor M1and the second electric motor M2are disposed coaxially with the drive apparatus input shaft14, the first electric motor M1is fixed to the first sun gear S1, and the second electric motor M2is fixed to the transmitting member18. However, such arrangement is not essential. For example, the first electric motor M1may be fixed to the first sun gear S1through gears, a belt or the like, and the second electric motor M2may be fixed to the transmitting member18.

Although the power distribution mechanism16is provided with both the switching clutch C0and the switching brake B0, it need not be provided with both of them, and may be provided with only one or none of the switching clutch C0and brake B0. Although the switching clutch C0selectively connects the sun gear S1and carrier CA1to each other, it may selectively connect the sun gear S1and ring gear R1to each other, or the carrier CA1and ring gear R1. In essence, the switching clutch C0sufficiently connects any two of the three elements of the first planetary gear set24.

The switching clutch C0in the embodiment is engaged to establish the neutral position “N” in the drive apparatus10, but the neutral position need not be established by engagement thereof.

The hydraulic-type frictional coupling devices such as the switching clutch C0and switching brake B0may be a coupling device of a magnetic-powder type, an electromagnetic type or a mechanical type, such as a powder (magnetic powder) clutch, an electromagnetic clutch and a meshing type dog clutch.

In the illustrated embodiment, further, although the drive apparatus10comprises the drive apparatus for hybrid vehicle in which the drive wheels38are driven with torques of the first electric motor M1and second electric motor M2in addition to the engine8, the present invention may also be applied even to a drive apparatus for vehicle in which the power distributing mechanism16has only a function of a continuously variable transmission, referred to as an electric CVT, in which no hybrid control is performed.

Furthermore, the power distributing mechanism16in the illustrated embodiment may comprise a differential gear unit wherein, for instance, a pinion drivably rotated with an engine and a pair of bevel gears meshing with the pinion are operatively connected to the first electric motor M1and second electric motor M2.

Moreover, while the power distributing mechanism16in the illustrated embodiment is composed of one set of planetary gear unit, it may comprise more than two planetary gear units that function as a power transmission with more than three stages in a fixed shifting state.

In the illustrated embodiment, further, although the second gear device comprises the automatic transmission20including three planetary gear units26,28,30, the second gear device may comprise a gear reduction mechanism including one planetary gear unit like a structure disclosed in the above Patent Publication 1. Furthermore, even in a case where the automatic transmission is employed as the second gear device, a structure of the automatic transmission is not limited to that of the illustrated embodiment and it is construed not to be particularly limited by the specific disclosure such as the number of planetary gear units, the number of gear-shift positions and which of the component elements of the planetary gear units is selectively coupled to the clutch C and the brake B.

In the illustrated embodiment, furthermore, while the second support wall122is fixed to the second case12bvia the bolts122, the second support wall122may be integrally formed with the second case12bso as to fix the second support wall122to the second case12b.

In the illustrated embodiment, moreover, the outer circumferential tubular portion106cof the first support wall106may be axially split into a plurality of tubular segments. Even if the outer circumferential tubular portion106care axially split into the plurality of tubular segments, all of these plural segments may be fastened to the second case12btogether with the second stator112of the second motor M2using the bolts124. Thus, the number of bolts does not increase and no deterioration takes place in assembling workability due to an increase in the number of bolts.

In the illustrated embodiment, further, the first support wall106or the second support wall122may be of the type that function as an oil pump body in which a pump rotor is accommodated.

Also, the particular arrangement described absolutely represents one illustrative embodiment, and the present invention can be implemented in various modifications and improvements, according to knowledge of the skilled person in this field.