Patent Description:
Conventionally, among hybrid vehicles including an engine and a rotating electric machine (a motor, a generator, and a motor generator), vehicles traveling while switching traveling modes are in practical use. A traveling mode includes an EV mode in which the vehicle travels only by a motor using charged power of a battery, a series mode in which the vehicle travels only by a motor while driving a generator to generate electric power by an engine, and a parallel mode in which the vehicle travels by using an engine and a motor together. The switching of the traveling mode is performed by controlling a mechanism such as a sleeve or a clutch interposed on a power transmission path inside a transaxle device. This mechanism is disposed on, for example, a shaft inside the power transmission path between the engine and the generator or a shaft inside the power transmission path between the engine and a drive wheel (see Patent Literatures <NUM> and <NUM>, <CIT>, <CIT> and <CIT>).

Incidentally, in the hybrid vehicle capable of individually outputting the power of the engine and the power of the motor, a power transmission path from the engine to the drive wheel and a power transmission path from the motor to the drive wheel are separately provided. Further, in such a hybrid vehicle, a traveling mode (a parallel mode) using the power of the engine is generally selected when a traveling load or a traveling speed increases. When the motor is used together in accordance with the necessity in the parallel mode, the motor rotates while being driven by the drive wheel during the traveling operation only using the engine. When a voltage caused by the rotation of the motor at this time exceeds a voltage of a driving battery, a regenerative brake acts on the vehicle and hence a driver may feel uncomfortable. Therefore, conventionally, an unexpected regenerative brake in a high-speed traveling state is prevented by a weak field control.

However, since electric power is consumed for the weak field control, this control is not desirable from the viewpoint of improvement in electricity cost.

The object of the invention is to provide a transaxle device capable of improving electricity cost. Furthermore, this object is not limited and another object of the invention is to exhibit operations and effects which are derived by each configuration illustrated in the embodiment for carrying out the invention to be described later and which is not obtainable by the conventional technique.

According to the invention, there is provided a transaxle device as defined in appended claim <NUM> and the corresponding dependent claims.

Since the connection/disconnection mechanism which enables or disables the transmission of the power of the first rotating electric machine is provided, it is possible to prevent the rotation of the drive wheel when the first rotating electric machine is turned off. For this reason, since the weak field control which has been performed conventionally is unnecessary, the electric power consumed by the weak field control can be used for a traveling operation. That is, since the connection/disconnection mechanism is provided, electricity cost can be improved.

A transaxle device of an embodiment will be described with reference to the drawings. Each of the following embodiments is merely an example and there is no intention to exclude the application of various modifications and techniques not mentioned in the following embodiments. The configurations of the embodiments can be modified into various forms within the scope of appended claims. Further, the configurations can be appropriately selected or combined within the scope of appended claims.

A transaxle <NUM> (a transaxle device) of the embodiment is applied to a vehicle <NUM> illustrated in <FIG>. The vehicle <NUM> is a hybrid vehicle which includes an engine <NUM>, a traveling motor <NUM> (an electric motor, a first rotating electric machine), and an electric power generator <NUM> (an electric power generator, a second rotating electric machine). The generator <NUM> is connected to the engine <NUM> and is operable independently from the operation state of the motor <NUM>. Further, the vehicle <NUM> is provided with three traveling modes including an EV mode, a series mode, and a parallel mode. These traveling modes are alternatively selected in response to a vehicle state, a travel state, or a driver's request output by an electronic control device (not illustrated) and hence the engine <NUM>, the motor <NUM>, and the generator <NUM> can be separately used in response to the type. It is to be noted that, the motor <NUM> may have a power generation function (a function of a generator) and the generator <NUM> may have an electric motor function (a function of a motor).

The EV mode is a traveling mode in which the vehicle <NUM> is driven only by the motor <NUM> using charged power of a driving battery (not illustrated) while the engine <NUM> and the generator <NUM> are stopped. The EV mode is selected in a case in which the traveling load and the traveling speed are low or the battery charge level is high. The series mode is a traveling mode in which the vehicle <NUM> is driven by the motor <NUM> using power while driving the generator <NUM> to generate electric power by the engine <NUM>. The series mode is selected in a case in which the traveling load and the traveling speed are intermediate or the battery charge level is low. The parallel mode is a traveling mode in which the vehicle <NUM> is mainly driven by the engine <NUM> and the driving of the vehicle <NUM> is assisted by the motor <NUM> as appropriate and is selected in a case in which the traveling load and the traveling speed are high.

The engine <NUM> and the motor <NUM> are connected in parallel to a drive wheel <NUM> through the transaxle <NUM> and the power of each of the engine <NUM> and the motor <NUM> is individually transmitted thereto. Further, the generator <NUM> and the drive wheel <NUM> are connected in parallel to the engine <NUM> through the transaxle <NUM> and the power of the engine <NUM> is also transmitted to the generator <NUM> in addition to the drive wheel <NUM>.

The transaxle <NUM> is a power transmission device which is obtained by integrating a final drive (a final speed reducer) including a differential gear <NUM> (a differential device, hereinafter referred to as the "differential <NUM>") and a transmission (a speed reducer) and includes a plurality of mechanisms which are in charge of transmission of power between a drive source and a driven device. The transaxle <NUM> of the embodiment is configured to be switchable between a high/low state (a high speed stage and a low speed stage). When the vehicle travels in the parallel mode, a high gear stage and a low gear stage are switched in response to the travel state or the request output by the electronic control device.

The engine <NUM> is an internal combustion engine (a gasoline engine or a diesel engine) which burns gasoline or light oil. The engine <NUM> is a so-called transverse engine in which a direction of a crankshaft 2a (a rotating shaft) is disposed laterally to be aligned with a vehicle width direction of the vehicle <NUM> and is fixed to the right side surface of the transaxle <NUM>. The crankshaft 2a is disposed in parallel to a drive shaft <NUM> of the drive wheel <NUM>. The operation state of the engine <NUM> is controlled by the electronic control device.

Both the motor <NUM> and the generator <NUM> are an electric power generator (a motor generator) which has a function of an electric motor and a function of an electric power generator. The motor <NUM> mainly functions as an electric motor to drive the vehicle <NUM> and functions as an electric power generator at the time of regeneration. The generator <NUM> functions as an electric motor (a starter) at the time of starting the engine <NUM> and generates electric power by the power of the engine at the time of operating the engine <NUM>. An inverter (not illustrated) which converts a DC current and an AC current is provided in the periphery (or the inside) of each of the motor <NUM> and the generator <NUM>. The rotation speed of each of the motor <NUM> and the generator <NUM> is controlled by controlling the inverter. The operation state of each of the motor <NUM>, the generator <NUM>, and each inverter is controlled by the electronic control device.

The motor <NUM> of the embodiment is formed such that an outer shape is formed in a cylindrical shape using a rotating shaft 3a as a center axis and is fixed to the left side surface of the transaxle <NUM> in a posture in which a bottom surface thereof faces the transaxle <NUM>. The generator <NUM> of the embodiment is formed such that an outer shape is formed in a cylindrical shape using a rotating shaft 4a as a center axis and is fixed to the left side surface of the transaxle <NUM> in a posture in which a bottom surface thereof faces the transaxle <NUM> similarly to the motor <NUM>.

<FIG> is a side view when the engine <NUM>, the motor <NUM>, the generator <NUM>, and a power train <NUM> including the transaxle <NUM> are viewed from the left side. The engine <NUM> is omitted in the side view. As illustrated in <FIG>, a pump <NUM> is fixed to the left side surface of the transaxle <NUM> in addition to the motor <NUM> and the generator <NUM>. The pump <NUM> is a hydraulic pressure generation device which pressure-feeds oil functioning as working oil or lubricating oil to a hydraulic circuit (not illustrated) using power of the drive wheel <NUM>.

<FIG> is a cross-sectional view in which the transaxle <NUM> of the embodiment is cut in the axial direction along the power transmission path, not forming part of the claimed subject-matter, and <FIG> is a skeleton diagram of the power train <NUM> including the transaxle <NUM>, not forming part of the claimed subject-matter. In the skeleton diagram after <FIG>, the pump <NUM> and the transaxle <NUM> are illustrated in an integrated state (a state in which the pump <NUM> is built in the casing 1C).

As illustrated in <FIG>, the transaxle <NUM> is provided with six shafts <NUM> to <NUM> which are arranged in parallel. Hereinafter, a rotating shaft which is coaxially connected to the crankshaft 2a will be referred to as an input shaft <NUM>. Similarly, rotating shafts which are coaxially connected to the drive shaft <NUM>, the rotating shaft 3a of the motor <NUM>, and the rotating shaft 4a of the generator <NUM> will be respectively referred to as an output shaft <NUM>, a motor shaft <NUM> (a first rotating electric machine shaft), and a generator shaft <NUM>. Further, a rotating shaft which is disposed on the power transmission path between the input shaft <NUM> and the output shaft <NUM> will be referred to as a first counter shaft <NUM> and a rotating shaft which is disposed on the power transmission path between the motor shaft <NUM> and the output shaft <NUM> will be referred to as a second counter shaft <NUM>.

As illustrated in <FIG>, both end portions of all of six shafts <NUM> to <NUM> are journaled to the casing 1C through bearings <NUM> to <NUM>. Further, an opening is formed in the side surface of the casing 1C located on each of the input shaft <NUM>, the output shaft <NUM>, the motor shaft <NUM>, and the generator shaft <NUM> and the shafts are connected to the crankshaft 2a and the like through the opening. Furthermore, a torque limiter <NUM> having a function of protecting the power transmission mechanism by interrupting excessive torque is interposed on the crankshaft 2a. As illustrated in <FIG>, the rotating shaft of the pump <NUM> is connected to the first counter shaft <NUM>.

Three power transmission paths are formed inside the transaxle <NUM>. Specifically, a power transmission path (hereinafter, referred to as a "first path <NUM>") extending from the motor shaft <NUM> to the output shaft <NUM>, a power transmission path (hereinafter, referred to as a "second path <NUM>") extending from the input shaft <NUM> to the output shaft <NUM>, and a power transmission path (hereinafter, referred to as a "third path <NUM>") extending from the input shaft <NUM> to the generator shaft <NUM> are formed as indicated by a two-dotted chain line in <FIG>.

The first path <NUM> (the first power transmission path) is a path which involves with the transmission of power from the motor <NUM> to the drive wheel <NUM> and is in charge of the transmission of power of the motor <NUM>. A connection/disconnection mechanism <NUM> to be described later is interposed in the course of the first path <NUM> to switch a power transmission enabled/disabled state. The second path <NUM> (the second power transmission path) is a path which involves with the transmission of power from the engine <NUM> to the drive wheel <NUM> and is in charge of the transmission of power during the operation of the engine <NUM>. A switching mechanism <NUM> to be described later is interposed in the course of the second path <NUM> to switch a power transmission enabled/disabled state and a high/low state. The third path <NUM> (the third power transmission path) is a path which involves with the transmission of power from the engine <NUM> to the generator <NUM> and is in charge of the transmission of power at the time of starting the engine and generating electric power by the engine <NUM>.

Next, a configuration of the transaxle <NUM> will be described in detail with reference to <FIG> and <FIG>. In the following description, the "fixed gear" means a gear which is integrated with the shaft and is not rotatable relative to the shaft. Further, the "idle gear" means a gear which is pivotally supported to the shaft so as to be relatively rotatable.

The input shaft <NUM> is provided with two fixed gears <NUM> and <NUM>. Two fixed gears <NUM> and <NUM> have different number of teeth and respectively normally engage with two idle gears <NUM> and <NUM> provided in the first counter shaft <NUM> to have different number of teeth.

In the embodiment, one fixed gear <NUM> having a small number of teeth is disposed at the right side (the side of the differential <NUM>) and the other fixed gear <NUM> having a large number of teeth is disposed at the left side (the opposite side to the differential <NUM> with respect to one fixed gear <NUM>). One fixed gear <NUM> having a small number of teeth engages with one idle gear <NUM> having a large number of teeth to form the low gear stage. In contrast, the other fixed gear <NUM> having a large number of teeth engages with the other idle gear <NUM> having a small number of teeth to form the high gear stage.

That is, in the first counter shaft <NUM>, the idle gear <NUM> having a large diameter is disposed at a position close to the differential <NUM> and the idle gear <NUM> having a small diameter is disposed at a position away from the differential <NUM>. Since the first counter shaft <NUM> is adjacent to the output shaft <NUM> having the differential <NUM> interposed therein, for example, a portion along the first counter shaft <NUM> in the casing 1C (a cylindrical portion indicated by the reference numeral 1a in <FIG>) can be decreased in diameter outward in a direction moving away from the differential <NUM> (a leftward direction in <FIG>) with the arrangement of these gears. Alternatively, since the cylindrical portion 1a is located at the left side of <FIG> in relation to the idle gear <NUM> having a large diameter when the casing 1C is provided so that a casing side surface 1b provided with an opening of the output shaft <NUM> is located at the outside in the radial direction between the idle gear <NUM> having a large diameter and the idle gear <NUM> having a small diameter, the cylindrical portion 1a can be decreased in size on the whole. With such a configuration, a space for connecting the drive shaft <NUM> is secured on the extension line of the output shaft <NUM> outside the casing 1C.

The low side fixed gear <NUM> normally engages with the fixed gear 14a provided in the generator shaft <NUM>. That is, the input shaft <NUM> and the generator shaft <NUM> are connected to each other through two fixed gears <NUM> and 14a so that power can be transmitted between the engine <NUM> and the generator <NUM>.

In the idle gear <NUM>, a left portion is provided with a tooth surface portion engaging with the fixed gear <NUM> and a dog gear 15d is provided to be coupled to a contact portion protruding from the right side of the tooth surface portion. In the idle gear <NUM>, a right portion is provided with a tooth surface portion engaging with the fixed gear <NUM> and a dog gear 15e is provided to be coupled to a contact portion protruding from the left side of the tooth surface portion. A front end portion (an outer end portion in the radial direction) of each of the dog gears 15d and 15e is provided with dog teeth (not illustrated).

The switching mechanism <NUM> is disposed between two idle gears <NUM> and <NUM> and is operable to control the power connection/disconnection state of the engine <NUM> and to switch a high gear stage and a low gear stage. The switching mechanism <NUM> of the embodiment includes a hub <NUM> which is fixed to the first counter shaft <NUM> and an annular sleeve <NUM> which is combined with the hub <NUM> (the first counter shaft <NUM>) so as not to be relatively rotatable and to be slidable in the axial direction of the first counter shaft <NUM>. The sleeve <NUM> moves to both left and right sides from a neutral position in the drawing when an actuator (not illustrated) is controlled by an electronic control device. Spline teeth (not illustrated) engaging with the dog teeth of the dog gears 15d and 15e are provided at the inside of the sleeve <NUM> in the radial direction. When the spline teeth engage with the dog teeth, the sleeve <NUM> engages with the dog gear 15d or the dog gear 15e.

When the sleeve <NUM> is located at a neutral position, two idle gears <NUM> and <NUM> are in an idle rotation state. In this case, even when the engine <NUM> is operated, the power of the engine <NUM> (the rotation of the input shaft <NUM>) is not transmitted to the output shaft <NUM>. That is, in this case, the transmission of the power of the engine <NUM> is interrupted.

When the sleeve <NUM> moves to any one of left and right sides from the neutral position so as to engage with one of the dog gears 15d and 15e of two idle gears <NUM> and <NUM>, the rotation of the input shaft <NUM> is transmitted to any one of the idle gears <NUM> and <NUM>. Hereinafter, this state will be referred to as a rotatable connection state. In the transaxle <NUM> of the embodiment, since the sleeve <NUM> moves to the right side so as to engage with the dog gear 15e of the idle gear <NUM>, the idle gear <NUM> of the low gear stage enters the rotational connection state with respect to the first counter shaft <NUM>. In contrast, when the sleeve <NUM> moves to the left side so as to engage with the dog gear 15d of the idle gear <NUM>, the idle gear <NUM> of the high gear stage enters the rotational connection state with respect to the first counter shaft <NUM>.

Further, the transaxle <NUM> of the embodiment synchronizes the rotation speed of the input shaft <NUM> (that is, the rotation speed of the idle gears <NUM> and <NUM>) with the rotation speed of the drive wheel <NUM> by the generator <NUM> in accordance with the movement of the sleeve <NUM>. That is, when the sleeve <NUM> engages with the dog gears 15d and 15e of at least one of the idle gears <NUM> and <NUM> (at the time of selecting the high gear stage or the low gear stage or switching the high gear stage and the low gear stage), an inverter of the generator <NUM> is controlled by an electronic control device so that the rotation speed of the input shaft <NUM> is adjusted to the rotation speed of the first counter shaft <NUM> before the engagement.

As this control method, for example, a method of detecting a rotation speed difference (a rotation difference) between the input shaft <NUM> and the drive wheel <NUM> by a sensor and applying a load from the generator <NUM> to the rotation of the input shaft <NUM> in response to the rotation speed difference to synchronize the rotation speed can be exemplified. Alternatively, a method of detecting the rotation speed of the drive wheel <NUM> by a sensor and controlling the rotation speed of the generator <NUM> to be synchronized with the rotation speed of the drive wheel can be exemplified.

As illustrated in <FIG> and <FIG>, the first counter shaft <NUM> is provided with a fixed gear 15a which is adjacent to the right side of the low side idle gear <NUM>. The fixed gear 15a normally engages with a ring gear 18a of the differential <NUM> provided in the output shaft <NUM>. Further, the first counter shaft <NUM> is provided with a pump <NUM> which is adjacent to the left side of the high side idle gear <NUM>. Oil pressure-fed from the pump <NUM> is supplied into a hydraulic circuit including an oil path inlet (not illustrated) provided in the first counter shaft <NUM> and an oil path inlet 5b provided in the motor shaft <NUM>.

The second counter shaft <NUM> is provided with two fixed gears 16a and 16b. In the fixed gear 16a close to the right side surface, a left portion is provided with a tooth surface portion normally engaging with the idle gear 13b provided in the motor shaft <NUM> and a parking gear <NUM> is integrated with the right side of the tooth surface portion. It is to be noted that, the idle gear 13b has a diameter smaller than that of the fixed gear 16a. That is, the number of teeth of the idle gear 13b is smaller than that of the fixed gear 16a. Meanwhile, the fixed gear 16b close to the left side surface normally engages with the ring gear 18a of the differential <NUM>.

The idle gear 13b of the motor shaft <NUM> constitutes the connection/disconnection mechanism <NUM> together with a clutch <NUM> interposed in the motor shaft <NUM>. That is, the connection/disconnection mechanism <NUM> of the embodiment is interposed in the motor shaft <NUM>. Specifically, as illustrated in <FIG>, the clutch <NUM> of the connection/disconnection mechanism <NUM> is interposed at a position overlapping the ring gear 18a of the differential <NUM> in a direction (hereinafter, referred to as a "width direction") orthogonal to the axial direction. Accordingly, it is possible to prevent an increase in axial dimension of the transaxle <NUM>.

The clutch <NUM> is a multiple disc type clutch which controls the power connection/disconnection state of the motor <NUM> and includes a first engagement component <NUM> fixed to the motor shaft <NUM> and a second engagement component <NUM> fixed to the idle gear 13b. The first engagement component <NUM> is one to which power is input from the motor <NUM> and the second engagement component <NUM> is one which outputs power to the drive wheel <NUM>. These engagement components <NUM> and <NUM> are driven in a separating direction (a disengagement direction) and an approaching direction (an engagement direction) in response to oil flowing from the oil path inlet 5b provided in the motor shaft <NUM>.

When the clutch <NUM> is engaged, the power of the motor <NUM> is transmitted to the drive wheel <NUM> through the idle gear 13b and the fixed gears 16a and 16b and the rotation of the drive wheel <NUM> is transmitted to the motor <NUM>. That is, when the clutch <NUM> is engaged, power running and regenerative power generation by the motor <NUM> becomes possible. In contrast, when the clutch <NUM> is disengaged while the vehicle travels by the engine <NUM> (the motor <NUM> is stopped), the idle gear 13b idly rotates and the rotation of the drive wheel <NUM> is not transmitted to the motor <NUM>. Accordingly, the motor <NUM> is not rotated and the resistance is reduced. The clutch <NUM> of the embodiment is controlled by a hydraulic pressure so as to be engaged during the operation of the motor <NUM> (in an on state) and to be disengaged during the stop of the motor <NUM> (in an off state).

It is to be noted that, a configuration may be employed in which a pressure regulator including a plurality of solenoid valves (an on/off solenoid valve, a linear solenoid valve, and the like) are provided on a hydraulic circuit and oil pressure-fed from the pump <NUM> is adjusted to an appropriate oil pressure so that the connection/disconnection of the clutch <NUM> is controlled. Alternatively, an electric coupling may be provided instead of the pump <NUM> and the multiple disc type clutch <NUM> so that the transmission of power is enabled or disabled by the electric control device. That is, the connection/disconnection mechanism <NUM> may include the electric coupling and the idle gear 13b.

The parking gear <NUM> is a component which constitutes a parking lock device. When a P range is selected by a driver, the parking gear engages with a parking sprag (not illustrated) to prohibit the rotation of the second counter shaft <NUM> (that is, the output shaft <NUM>).

As illustrated in <FIG>, the differential <NUM> transmits power transmitted to the ring gear 18a to the output shaft <NUM> through a differential casing 18b, a pinion shaft 18c, a differential pinion 18d, and a side gear 18e.

The above-described transaxle <NUM> is an example and a configuration thereof is not limited to the above-described configuration. Hereinafter, modified examples of the transaxle <NUM> will be described with reference to <FIG> are skeleton diagrams illustrating the power train <NUM> including the transaxle <NUM> according to first to tenth modified examples. In the components of the above-described embodiment or the modified examples, the same reference numerals as those of the above-described embodiment or the modified examples or the similar reference numerals (reference numerals having the same numbers and different alphabets) will be given to the components and a repetitive description thereof will be omitted.

As illustrated in <FIG>, the transaxle <NUM> according to a first modified example has the same configuration as that of the above-described embodiment except for the structure of connecting the input shaft <NUM> and the generator shaft <NUM> and the arrangement of a connection/disconnection mechanism <NUM>' on the second counter shaft <NUM>. In the transaxle <NUM> of the modified example, a fixed gear 11a normally engaging with the fixed gear 14a of the generator <NUM> is provided in the input shaft <NUM> and power can be transmitted between the engine <NUM> and the generator <NUM> by the fixed gears 11a and 14a. It is to be noted that, the above-described fixed gear <NUM> normally engages with only the idle gear <NUM> of the first counter shaft <NUM>.

Further, the connection/disconnection mechanism <NUM>' of the modified example includes an idle gear 16c which is provided in the second counter shaft <NUM> and a clutch <NUM>' which is interposed in the second counter shaft <NUM>. The idle gear 16c has a diameter larger than that of the fixed gear 13a provided in the motor shaft <NUM> (that is, the number of teeth of the idle gear is larger than that of the fixed gear) and normally engages with the fixed gear 13a. Similarly to the above-described embodiment, the clutch <NUM>' is a multiple disc type clutch which controls the power connection/disconnection state of the motor <NUM> and includes a first engagement component <NUM>' which is fixed to the second counter shaft <NUM> and a second engagement component <NUM>' which is fixed to the idle gear 16c. These engagement components <NUM>' and <NUM>' are driven in a separating direction (a disengagement direction) and an approaching direction (an engagement direction) in response to the hydraulic pressure of oil flowing from the oil path inlet 5c provided in the second counter shaft <NUM>.

According to the transaxle <NUM> of the modified example in which the connection/disconnection mechanism <NUM>' is interposed in the second counter shaft <NUM>, since the second counter shaft <NUM> rotates in synchronization when the output shaft <NUM> rotates, it is possible to easily supply oil from the end portion (the oil path inlet 5c) of the second counter shaft <NUM> into the second counter shaft <NUM> (the idle gear 16c on the second counter shaft <NUM>). Further, in the modified example, since the idle gear 16c having more teeth (a diameter larger) than the fixed gear 13a is provided in the second counter shaft <NUM>, it is possible to decrease the rotation speed of the idle gear 16c as compared with a case in which the idle gear having a small diameter is disposed in the motor shaft <NUM> (for example, a configuration of <FIG>). Accordingly, a needle bearing of the idle gear 16c can be used within an allowable rotation speed.

Further, also in the transaxle <NUM> of the modified example, the electricity cost can be improved similarly to the above-described embodiment. Furthermore, the same effect can be obtained from the same configuration as that of the above-described embodiment. It is to be noted that, since the input shaft <NUM> of the modified example is provided with the fixed gear <NUM> transmitting power to the output shaft <NUM> and the fixed gear 11a transmitting power to the generator <NUM>, it is possible to easily design each gear ratio to a desired value while shortening a dimension in a direction orthogonal to the axial direction (a radial direction of the gear).

As illustrated in <FIG>, the transaxle <NUM> according to a second modified example has the same configuration as that of the above-described first modified example (<FIG>) except that the positional relationship between the high gear stage and the low gear stage and the configuration of a switching mechanism <NUM>' are different. In the modified example, the high gear stage (the fixed gear <NUM>, a fixed gear <NUM>') is disposed at the right side (the side of the differential <NUM>) inside the casing 1C and the low gear stage (the fixed gear <NUM>, the idle gear <NUM>) is disposed at the left side inside the casing 1C. In the modified example, the fixed gear <NUM>' provided in the first counter shaft <NUM> normally engages with the fixed gear <NUM> of the input shaft <NUM> to form the high gear stage.

The input shaft <NUM> of the modified example is provided with the fixed gear 11a which has the same configuration as that of the first modified example and is disposed between two fixed gears <NUM> and <NUM>. Further, the first counter shaft <NUM> is provided with the high side fixed gear <NUM>', the output idle gear 15b, the low side idle gear <NUM>, and the switching mechanism <NUM>' in order from the right side. The switching mechanism <NUM>' includes a hub <NUM>' which is provided in the first counter shaft <NUM> so as not to be relatively rotatable and an annular sleeve <NUM>' which is combined with the hub <NUM>' so as not to be relatively rotatable and to be slidable in the axial direction of the first counter shaft <NUM>.

Dog gears 15d' and 15e which engage with spline teeth of the sleeve <NUM>' are provided at both left and right sides of the sleeve <NUM>'. In the modified example, the dog gear 15d' at the left side of the sleeve <NUM>' is fixed to the first counter shaft <NUM> and is rotatable together with the high side fixed gear <NUM>' through the first counter shaft <NUM>. It is to be noted that, the right dog gear 15e has the same configuration as that of the above-described embodiment. A right portion of the idle gear 15b is provided with a tooth surface portion which engages with the ring gear 18a of the differential <NUM> and the hub <NUM>' of the switching mechanism <NUM>' is coupled to a front end of a cylindrical portion protruding from the left side of the tooth surface portion (that is, a left portion of the idle gear 15b). The low side idle gear <NUM> is pivotally supported to the outer periphery of the cylindrical portion of the idle gear 15b so as to be relatively rotatable. That is, these two idle gears <NUM> and 15b form a double pipe structure.

When the sleeve <NUM>' is located at a neutral position, the output idle gear 15b becomes an idle rotation state and hence the transmission of power of the engine <NUM> is interrupted. When the sleeve <NUM>' moves to any one of the left and right sides from the neutral position to engage with the dog gears 15d' and 15e at one side, any one of the rotation of the fixed gear <NUM>' and the rotation of the idle gear <NUM> is transmitted to the idle gear 15b. That is, when the sleeve <NUM>' moves to the right side to engage with the dog gear 15e of the idle gear <NUM>, the low gear stage is selected. In contrast, when the sleeve <NUM>' moves to the left side to engage with the dog gear 15d', the high gear stage is selected.

The casing 1C of the modified example is formed in a cylindrical shape in which the periphery of the first counter shaft <NUM> protrudes outward (leftward) in the axial direction. The cylindrical protrusion portion (hereinafter, referred to as a "cylindrical portion 1D") is formed with an arrangement and a shape not interfering with any of the motor <NUM> and the generator <NUM> when the motor <NUM> and the generator <NUM> are attached to the casing 1C. The cylindrical portion 1D is disposed in an area between the rotating shaft 3a (the motor shaft <NUM>) of the motor <NUM> and the rotating shaft 4a (the generator shaft <NUM>) of the generator <NUM> when a power train <NUM> is viewed from the left side (in the side view). Here, "the area" above mentioned means an area interposed between two lines orthogonal to a line connecting two shafts 3a and 4a and passing through the shafts 3a and 4a in the side view. The switching mechanism <NUM>' is built in the cylindrical portion 1D.

That is, in the transaxle <NUM> according to the modified example, since the casing 1C is partially increased in size only at a portion in which the switching mechanism <NUM>' is disposed, an increase in size of the transaxle <NUM> can be prevented. Further, since the cylindrical portion 1D is disposed in a region between the rotating shafts 3a and 4a of the motor <NUM> and the generator <NUM>, an increase in size of the power train <NUM> including the transaxle <NUM> can be prevented. Furthermore, it is possible to obtain the same effect from the same configuration as those of the above-described embodiment and the first modified example.

As illustrated in <FIG>, the transaxle <NUM> according to a third modified example has the same configuration as that of the above-described first modified example (<FIG>) except that the positional relationship between the high gear stage and the low gear stage and the configuration of a switching mechanism <NUM> are different. In the modified example, the high gear stage (the fixed gear <NUM>, an idle gear <NUM>) is disposed at the right side (the side of the differential <NUM>) inside the casing 1C and the low gear stage (the fixed gear <NUM>, an idle gear <NUM>) is disposed at the left side inside the casing 1C. It is to be noted that, the fixed gear 11a which is the same as that of the first modified example is provided at the right side of the high side fixed gear <NUM> in the input shaft <NUM> of the modified example.

The first counter shaft <NUM> is provided with the fixed gear 15a, the high side idle gear <NUM>, the low side idle gear <NUM>, and he switching mechanism <NUM> in order from the right side. The switching mechanism <NUM> of the modified example is used to control the power connection/disconnection state of the engine <NUM> and to switch the high gear stage and the low gear stage and is built in the cylindrical portion 1D of the casing 1C similarly to the above-described second modified example. The switching mechanism <NUM> is obtained by a combination of a high side multiple disc type clutch (a high side clutch) connecting or disconnecting the high gear stage with respect to the second path <NUM> and a low side multiple disc type clutch (a low side clutch) connecting or disconnecting the low gear stage with respect to the second path <NUM>. The working hydraulic pressure of each clutch is supplied from two oil path inlets 5a and 5a' provided in the first counter shaft <NUM>.

The switching mechanism <NUM> includes two engagement components <NUM> and <NUM> constituting the high side clutch and two engagement components <NUM> and <NUM> constituting the low side clutch. The drive side engagement components <NUM> and <NUM> are respectively fixed to two idle gears <NUM> and <NUM> so that power is input from the engine <NUM> thereto. Meanwhile, the driven side engagement components <NUM> and <NUM> are respectively fixed to the first counter shaft <NUM> so that power is output to the drive wheel <NUM>.

Two idle gears <NUM> and <NUM> are disposed on the same shaft (the first counter shaft <NUM>) to form a double pipe structure. Specifically, in the high side idle gear <NUM>, a right portion is provided with a tooth surface portion which engages with the fixed gear <NUM> and an engagement component <NUM> is fixed to a front end of a cylindrical portion (that is, a left portion of the idle gear <NUM>) protruding from the left side of the tooth surface portion. Further, in the low side idle gear <NUM>, an engagement component <NUM> is fixed to the left side of the tooth surface portion engaging with the fixed gear <NUM>. Furthermore, the idle gear <NUM> is pivotally supported to the outer periphery of the cylindrical portion of the high side idle gear <NUM> so as to be relatively rotatable.

Each of the engagement components <NUM> and <NUM> of the high side clutch and the engagement components <NUM> and <NUM> of the low side clutch is driven in a separating direction (a disengagement direction) and an approaching direction (an engagement direction) in response to the hydraulic pressure of oil flowing from the oil path inlets 5a and 5a'. When all of the engagement components <NUM>, <NUM>, <NUM>, and <NUM> of the switching mechanism <NUM> are disengaged, two idle gears <NUM> and <NUM> become an idle rotation state so that the transmission of power of the engine <NUM> is interrupted. Meanwhile, when one of the high and low side clutches of the switching mechanism <NUM> is engaged and the other thereof is disengaged, the high gear stage or the low gear stage is selected so that the power of the engine <NUM> is transmitted to the output shaft <NUM>.

In this way, according to the transaxle <NUM> of the modified example, since two idle gears <NUM> and <NUM> are disposed on the first counter shaft <NUM> to form a double pipe structure and the high/low state is switched by one switching mechanism <NUM> interposed in the same shaft, the transaxle <NUM> can be provided in a compact size. Further, in the transaxle <NUM> of the modified example, since the casing 1C may be partially increased in size only in a portion in which the switching mechanism <NUM> is disposed similarly to the above-described second modified example, an increase in size of the transaxle <NUM> can be prevented. Furthermore, when the cylindrical portion 1D having the switching mechanism <NUM> built therein is disposed in a region between the rotating shafts 3a and 4a of the motor <NUM> and the generator <NUM>, an increase in size of the power train <NUM> including the transaxle <NUM> can be also prevented. It is to be noted that, it is possible to obtain the same effect from the same configuration as those of the above-described embodiment and the modified examples.

As illustrated in <FIG>, in the transaxle <NUM> according to a fourth modified example not forming part of the claimed subject-matter, the connection/disconnection mechanism <NUM> of the above-described embodiment is interposed in the motor shaft <NUM>. Here, the connection/disconnection mechanism <NUM> of the modified example is interposed at the right side of the ring gear 18a of the differential <NUM>. Further, the transaxle <NUM> of the modified example is different from those of the above-described embodiment and the modified examples in that the power transmission path from the input shaft <NUM> to the output shaft <NUM> is different in the high gear stage and the low gear stage. Furthermore, a dashed line in the drawing indicates a state in which the gears engage with each other.

The high gear stage of the modified example is formed of the high side fixed gear <NUM> provided in the input shaft <NUM> and the high side idle gear <NUM> provided in the second counter shaft <NUM>. That is, the high gear stage is provided on a path extending from the input shaft <NUM> to the output shaft <NUM> through the second counter shaft <NUM>. The fixed gear <NUM> and the idle gear <NUM> normally engage with each other and the idle gear <NUM> is connected or disconnected with respect to the second counter shaft <NUM> by the high side clutch <NUM> interposed in the second counter shaft <NUM>. It is to be noted that, the second counter shaft <NUM> of the modified example is disposed in proximity to the input shaft <NUM> in relation to the position illustrated in <FIG>.

Similarly to the above-described embodiment, the low gear stage of the modified example is formed of the low side fixed gear <NUM> provided in the input shaft <NUM> and the low side idle gear <NUM> provided in the first counter shaft <NUM>. That is, the low gear stage is provided on a path (the second path <NUM>) extending from the input shaft <NUM> to the output shaft <NUM> through the first counter shaft <NUM>. In the input shaft <NUM> of the modified example, the left end is provided with the low side fixed gear <NUM> and the right end is provided with the high side fixed gear <NUM>. In the modified example, the parking gear <NUM> is provided in the first counter shaft <NUM>, but the arrangement of the parking gear <NUM> is not particularly limited.

The switching mechanism of the modified example includes the high side clutch <NUM> and the low side clutch <NUM> similarly to the third modified example, but is different in that these clutches are separated from each other. As described above, the high side clutch <NUM> is interposed in the second counter shaft <NUM> and the low side clutch <NUM> is interposed in the first counter shaft <NUM>. In the modified example, the high side clutch <NUM> is disposed at a position located at the right side of the ring gear 18a of the differential <NUM> and overlapping the clutch <NUM> on the motor shaft <NUM> in the width direction. Further, the low side clutch <NUM> is disposed inside the cylindrical portion 1D.

Similarly to the third modified example, the high side clutch <NUM> is a multiple disc type clutch including two engagement components <NUM> and <NUM> and is driven in a separating direction (a disengagement direction) and an approaching direction (an engagement direction) in response to the hydraulic pressure supplied from the oil path inlet 5c provided in the second counter shaft <NUM>. The low side clutch <NUM> is also a multiple disc type clutch including two engagement components <NUM> and <NUM> and is driven in a separating direction (a disengagement direction) and an approaching direction (an engagement direction) in response to the hydraulic pressure supplied from the oil path inlet 5a.

When all of the high and low side clutches <NUM> and <NUM> are disengaged, two idle gears <NUM> and <NUM> become an idle rotation state so that the transmission of power of the engine <NUM> is interrupted. Further, when any one of the high and low side clutches <NUM> and <NUM> is engaged and the other thereof is disengaged, the high gear stage or the low gear stage is selected so that the power of the engine <NUM> is transmitted to the output shaft <NUM>. In this way, according to the transaxle <NUM> of the modified example, since the high and low side clutches <NUM> and <NUM> are provided, the configuration of the switching mechanism can be simplified.

Further, since the casing 1C may be increased in sized only in a portion (the cylindrical portion 1D) in which the low side clutch <NUM> is disposed similarly to the above-described second modified example, an increase in size of the transaxle <NUM> can be prevented and an increase in size of the power train <NUM> including the transaxle <NUM> can be also prevented. Furthermore, since the high side clutch <NUM> and the clutch <NUM> are disposed so as to overlap each other in the width direction, an increase in axial dimension can be prevented and hence an increase in size can be prevented. It is to be noted that, it is possible to obtain the same effect from the same configuration as that of the above-described embodiment.

As illustrated in <FIG>, the transaxle <NUM> according to the fifth modified example not forming part of the claimed subject-matter is different from that of the above-described fourth modified example (<FIG>) in that the connection/disconnection mechanism <NUM>' is provided in the second counter shaft <NUM>. That is, similarly to the above-described first modified example, in the transaxle <NUM> of the modified example, the power connection/disconnection state of the motor <NUM> is controlled by the connection/disconnection mechanism <NUM>' including the clutch <NUM>' and the idle gear 16c provided in the second counter shaft <NUM>. It is to be noted that, the second counter shaft <NUM> is provided with oil path inlets 5c and 5c' respectively supplying a hydraulic pressure to the clutch <NUM>' and the high side clutch <NUM>. Also in such a configuration, it is possible to obtain the same effect from the same configuration as those of the above-described embodiment and the first and fourth modified examples.

As illustrated in <FIG>, in the transaxle <NUM> according to a sixth modified example, the connection/disconnection mechanism <NUM>' of the above-described first modified example (<FIG>) is interposed in the second counter shaft <NUM>. Further, similarly to the above-described fourth modified example (<FIG>), the transaxle <NUM> is provided so that the power transmission path extending from the input shaft <NUM> to the output shaft <NUM> is different for the high gear stage and the low gear stage, but the arrangement is different from that of the fourth modified example. Furthermore, similarly to the fourth modified example, the switching mechanism of the modified example the high side clutch <NUM>' and the low side clutch <NUM>' are separated from each other.

Similarly to the above-described embodiment, the high gear stage of the modified example is formed of the high side fixed gear <NUM> provided in the input shaft <NUM> and the high side idle gear <NUM> provided in the first counter shaft <NUM>. The high side clutch <NUM>' is used to connect or disconnect the idle gear <NUM> with respect to the first counter shaft <NUM> and is disposed inside the cylindrical portion 1D on the first counter shaft <NUM>. The high side clutch <NUM>' is a multiple disc type clutch including two engagement components <NUM>' and <NUM>' and is driven in a separating direction (a disengagement direction) and an approaching direction (an engagement direction) in response to the hydraulic pressure supplied from the oil path inlet 5a.

The low gear stage of the modified example is formed of the low side fixed gear <NUM> provided in the input shaft <NUM> and the low side idle gear <NUM> provided in the second counter shaft <NUM>. That is, the low gear stage is provided on a path extending from the input shaft <NUM> to the output shaft <NUM> through the second counter shaft <NUM>. The fixed gear <NUM> and the idle gear <NUM> normally engage with each other and the idle gear <NUM> is connected or disconnected with respect to the second counter shaft <NUM> by the low side clutch <NUM>' interposed in the second counter shaft <NUM>.

The low side clutch <NUM>' is a multiple disc type clutch including two engagement components <NUM>' and <NUM>' and is driven in a separating direction (a disengagement direction) and an approaching direction (an engagement direction) in response to the hydraulic pressure supplied from the oil path inlet 5c. In the input shaft <NUM> of the modified example, the high side fixed gear <NUM> is provided at the left end and the low side fixed gear <NUM> is provided adjacent to the right side of the fixed gear <NUM>. Further, the low side clutch <NUM>' is disposed at the left side of the fixed gear 16b engaging with the ring gear 18a of the differential <NUM>.

Similarly to the above-described fourth modified example, when the high and low side clutches <NUM>' and <NUM>' are disengaged, the transmission of power of the engine <NUM> is interrupted. Further, when any one of the high and low side clutches <NUM>' and <NUM>' is engaged and the other thereof is disengaged, the high gear stage or the low gear stage is selected so that the power of the engine <NUM> is transmitted to the output shaft <NUM>. In this way, also in the transaxle <NUM> of the modified example, it is possible to obtain the same effect from the same configuration as those of the above-described embodiment and the modified examples.

As illustrated in <FIG>, in the transaxle <NUM> according to a seventh modified example not forming part of the claimed subject-matter, the connection/disconnection mechanism <NUM> is interposed in the motor shaft <NUM> similarly to the above-described embodiment (<FIG> and <FIG>). Here, the modified example is different from the above-described embodiment in that the clutch <NUM> is provided at the right side of the idle gear 13b and the engagement timing of the clutch <NUM> is different. Further, similarly to the above-described fourth modified example (<FIG>), the transaxle <NUM> is provided so that the power transmission path extending from the input shaft <NUM> to the output shaft <NUM> is different for the high gear stage and the low gear stage. Here, the power transmission path of the high gear stage is different from that of the fourth modified example.

The high gear stage of the modified example is formed of the high side fixed gear <NUM> provided in the input shaft <NUM>, the high side idle gear <NUM> provided in the motor shaft <NUM>, and the idle gear 17a provided therebetween. The idle gear 17a is a gear for matching the rotation direction, is disposed in parallel to six shafts <NUM> to <NUM>, and is fixed to an intermediate shaft <NUM> provided between the input shaft <NUM> and the motor shaft <NUM>. All of the fixed gear <NUM> and the idle gear <NUM> normally engage with the idle gear 17a.

In the motor shaft <NUM>, a high side clutch <NUM> is provided at the left side of the connection/disconnection mechanism <NUM>. The high side clutch <NUM> is used to connect or disconnect the idle gear <NUM> with respect to the motor shaft <NUM> and is disposed at a position overlapping the ring gear 18a of the differential <NUM> in the width direction. That is, the high gear stage of the modified example is provided on a path extending from the input shaft <NUM> to the output shaft <NUM> through the intermediate shaft <NUM>, the motor shaft <NUM>, and the second counter shaft <NUM>. The high side clutch <NUM> is also a multiple disc type clutch including two engagement components <NUM> and <NUM> and is driven in a separating direction (a disengagement direction) and an approaching direction (an engagement direction) in response to the hydraulic pressure supplied from the oil path inlet 5b' provided in the motor shaft <NUM>.

When all of the high and low side clutches <NUM> and <NUM> are disengaged, two idle gears <NUM> and <NUM> become an idle rotation state so that the transmission of power of the engine <NUM> is interrupted. Further, when any one of the high and low side clutches <NUM> and <NUM> is engaged and the other thereof is disengaged, the high gear stage or the low gear stage is selected. Here, the clutch <NUM> of the modified example is controlled by the hydraulic pressure so as to be engaged when the high gear stage is selected even when the motor <NUM> is stopped (in an off state) in addition to the operation state of the motor <NUM>. Accordingly, the power of the engine <NUM> is transmitted to the output shaft <NUM>. Furthermore, at least the low gear stage is selected when the clutch <NUM> is disengaged.

Thus, according to the transaxle <NUM> of the modified example, since the power transmission path of the motor <NUM> is disconnected by the connection/disconnection mechanism <NUM> while the motor <NUM> is stopped and the low gear stage is selected, it is possible to prevent the rotation of the motor <NUM> and to contribute to the improvement in electricity cost. Further, also in the modified example, since the dead space can be efficiently used, the high gear stage or the low gear stage can be set without increasing the axial dimension of the transaxle <NUM>. Furthermore, it is possible to obtain the same effect from the same configuration as those of the above-described embodiment and the modified examples.

As illustrated in <FIG>, in the transaxle <NUM> according to an eighth modified example not forming part of the claimed subject-matter, the connection/disconnection mechanism <NUM> which is the same as that of the above-described seventh modified example is interposed in the motor shaft <NUM>. Further, the transaxle <NUM> is different from that of the above-described seventh modified example (<FIG>) in that the positional relationship between the high gear stage and the low gear stage is different and a switching mechanism <NUM> is provided in the intermediate shaft <NUM>.

Similarly to the above-described embodiment, in the transaxle <NUM>, the low gear stage is disposed at the right side and the high gear stage is disposed at the left side. Furthermore, the configuration of the high gear stage is the same as that of the sixth modified example. The low gear stage of the modified example includes the low side fixed gear <NUM> provided in the input shaft <NUM>, a low side fixed gear <NUM> provided in the motor shaft <NUM>, and an idle gear 17b provided therebetween. The idle gear 17b is a gear provided in the intermediate shaft <NUM> to match the rotation direction similarly to the seventh modified example. Here, the idle gear 17b is provided as an idle gear differently from the seventh modified example. Furthermore, both fixed gears <NUM> and <NUM> normally engage with the idle gear 17b.

The low side clutch <NUM> interposed in the intermediate shaft is a multiple disc type clutch including two engagement components <NUM> and <NUM> and is driven in a separating direction (a disengagement direction) and an approaching direction (an engagement direction) in response to the hydraulic pressure supplied from the oil path inlet 5d in the intermediate shaft <NUM>. The idle gear 17b is fixed to the engagement component <NUM> and the low side clutch <NUM> connects or disconnects the idle gear 17b with respect to the intermediate shaft <NUM>.

When both high and low side clutches <NUM>' and <NUM> are disengaged, two idle gears <NUM> and 17b become an idle rotation state so that the transmission of power of the engine <NUM> is interrupted. Further, when any one of the high and low side clutches <NUM>' and <NUM> is engaged or the other thereof is disengaged, the high gear stage or the low gear stage is selected. Here, the clutch <NUM> of the modified example is controlled by the hydraulic pressure so as to be engaged when the low gear stage is selected even when the motor <NUM> is stopped (in an off state) in addition to the operation state of the motor <NUM>. Accordingly, the power of the engine <NUM> is transmitted to the output shaft <NUM>. Furthermore, the clutch <NUM> is disengaged when at least the high gear stage is selected.

Thus, according to the transaxle <NUM> of the modified example, since the power transmission path of the motor <NUM> is disengaged by the connection/disconnection mechanism <NUM> while the motor <NUM> is stopped and the high gear stage is selected, it is possible to prevent the rotation of the motor <NUM> and to contribute to the improvement in electricity cost. Further, also in the modified example, since it is possible to efficiently use the dead space, it is possible to set the high gear stage or the low gear stage without increasing the axial dimension of the transaxle <NUM>. Furthermore, it is possible to obtain the same effect from the same configuration as those of the above-described embodiment and the modified examples.

As illustrated in <FIG>, the transaxle <NUM> according to a ninth modified example not forming part of the claimed subject-matter has the same configuration as that of the above-described first modified example (<FIG>) except that the configuration of the switching mechanism and the configuration of the connection/disconnection mechanism are different.

First, the switching mechanism of the modified example will be described. The switching mechanism includes two selection mechanisms 30A and 30B respectively selecting the high gear stage and the low gear stage. One selection mechanism 30A is interposed in the input shaft <NUM> and the other selection mechanism 30B is interposed in the first counter shaft <NUM>. Further, these selection mechanisms 30A and 30B are disposed at an overlapping position in the width direction.

The selection mechanism 30A includes a hub 31A which is fixed to the input shaft <NUM> and an annular sleeve 32A which is combined with the hub 31A (the input shaft <NUM>) so as not to be relatively rotatable and to be slidable in the axial direction of the input shaft <NUM>. Similarly, the selection mechanism 30B includes a hub 31B which is fixed to the first counter shaft <NUM> and an annular sleeve 32B which is combined with the hub 31B (the first counter shaft <NUM>) so as not to be relatively rotatable and to be slidable in the axial direction of the first counter shaft <NUM>. These sleeves 32A and 32B also include spline teeth (not illustrated) provided at the inside in the radial direction.

Further, in the input shaft <NUM>, the fixed gear <NUM> is provided at the left side of the selection mechanism 30A and an idle gear <NUM>' having a small number of teeth as compared with the fixed gear <NUM> is provided at the right side of the selection mechanism 30A. Furthermore, in the first counter shaft <NUM>, the idle gear <NUM> is provided at the left side of the selection mechanism 30B and a fixed gear <NUM>' having a large number of teeth as compared with the idle gear <NUM> is provided at the right side of the selection mechanism 30B. The fixed gear <NUM>' and the idle gear <NUM>' normally engage with each other. Further, in the idle gear <NUM>', a right portion is provided with a tooth surface portion which engages with the fixed gear <NUM>' and a dog gear 11e is provided to be coupled to a contact portion protruding from the left side of the tooth surface portion. Furthermore, the dog gear 11e also includes dog teeth (not illustrated) provided at a front end portion thereof.

When all of sleeves 32A and 32B are located at a neutral position, two idle gears <NUM> and <NUM>' become an idle rotation state so that the transmission of power of the engine <NUM> is interrupted. When the sleeve 32A moves rightward from an idle rotation state to engage with the dog gear 11e of the idle gear <NUM>' while the sleeve 32B is located at the neutral position, the power of the engine <NUM> (the rotation of the input shaft <NUM>) is transmitted to the output shaft <NUM> through the idle gear <NUM>' and the fixed gear <NUM>'. That is, in this case, the idle gear <NUM>' of the low gear stage enters the rotational connection state with respect to the input shaft <NUM>. Further, when the sleeve 32B moves leftward from an idle rotation state to engage with the dog gear 15d of the idle gear <NUM> while the sleeve 32A is located at the neutral position, the power of the engine <NUM> is transmitted to the output shaft <NUM> through the fixed gear <NUM> and the idle gear <NUM>. That is, in this case, the idle gear <NUM> of the high gear stage enters the rotational connection state with respect to the first counter shaft <NUM>.

In this way, according to the transaxle <NUM> of the modified example, since one of two selection mechanisms 30A and 30B constituting the switching mechanism is disposed on the input shaft <NUM>, loss caused by an oil bath can be prevented. Further, since it is possible to switch the high/low state by simultaneously operating two selection mechanisms 30A and 30B, it is possible to shorten a time for switching the high/low state as compared with a case in which one switching mechanism <NUM> is provided and to promptly switch the high/low state.

Next, a connection/disconnection mechanism <NUM>" of the modified example will be described. The connection/disconnection mechanism <NUM>" includes a hub <NUM> which is fixed to the second counter shaft <NUM> and an annular sleeve <NUM> which is combined with the hub <NUM> (the second counter shaft <NUM>) so as not to be relatively rotatable and to be slidable in the axial direction. Spline teeth (not illustrated) are provided at the inside of the sleeve <NUM> in the radial direction. Further, in the second counter shaft <NUM>, an idle gear 16d is provided at the right side of the connection/disconnection mechanism <NUM>' '. The number of teeth of the idle gear 16d is larger than that of the fixed gear 13a of the motor shaft <NUM>, a right portion thereof is provided with a tooth surface portion normally engaging with the fixed gear 13a, and a dog gear 16e is provided to be coupled to a contact portion protruding from the left side of the tooth surface portion. Furthermore, the dog gear 16e also includes dog teeth (not illustrated) provided at a front end portion thereof.

When the sleeve <NUM> is located at a neutral position, the idle gear 16d becomes an idle rotation state so that the transmission of power of the first path <NUM> is interrupted. When the sleeve <NUM> moves in the axial direction (rightward) to engage with the dog gear 16e of the idle gear 16d, the idle gear 16d enters the rotational connection state with respect to the second counter shaft <NUM> so that power can be transmitted through the first path <NUM>. That is, the power of the motor <NUM> is transmitted to the output shaft <NUM>.

In this way, according to the transaxle <NUM> of the modified example, since it is possible to switch the power transmission state by the sleeve <NUM>, a gear ratio is not limited and a degree of freedom in design can be improved. Further, in the modified example, since the connection/disconnection mechanism <NUM>'' and the idle gear 16d are interposed in the second counter shaft <NUM>, the idle gear 16d idly rotates even when the second counter shaft <NUM> rotates in accordance with the rotation of the output shaft <NUM>. For this reason, even when a part or all of the idle gear 16d is in an oil bath state, oil inside the transaxle <NUM> is not stirred and hence the efficiency of the transaxle <NUM> is not deteriorated.

It is to be noted that, it is possible to obtain the same effect from the same configuration as those of the above-described embodiment and the modified examples. Further, in the modified example, a configuration in which the connection/disconnection mechanism <NUM>' ' is interposed in the second counter shaft <NUM> has been disclosed, but the connection/disconnection mechanism including the hub <NUM> and the sleeve <NUM> may be provided in a shaft (for example, the motor shaft <NUM>) on the first path <NUM>.

As illustrated in <FIG>, the transaxle <NUM> according to a tenth modified example has the same configuration as that of the above-described ninth modified example (<FIG>) except for the positional relationship between the idle gear 16d and the connection/disconnection mechanism <NUM>' ' on the second counter shaft <NUM>. That is, in the modified example, the idle gear 16d is disposed at the left side of the connection/disconnection mechanism <NUM>'' (at a side close to the differential <NUM>). According to the transaxle <NUM> with such an arrangement, since the position of the fixed gear 13a on the motor shaft <NUM> is closer to the motor <NUM> as compared with <FIG>, it is possible to shorten the length of the motor shaft <NUM> and to decrease the size of the casing 1C. Furthermore, it is possible to obtain the same effect from the same configuration as those of the above-described embodiment and the modified examples.

While the embodiment and the modified examples of the invention have been described, the invention is not limited to the above-described embodiment and the like and can be modified into various forms within the scope of appended claims.

In the above-described embodiment and the modified examples, the transaxle <NUM> in which the switching mechanism (or a part of the switching mechanism) for switching the high gear stage and the low gear stage is interposed in the first counter shaft <NUM> has been exemplified, but the arrangement of the switching mechanism is not particularly limited. For example, the switching mechanism may be interposed in the input shaft <NUM>. The switching mechanism is not an indispensable configuration and can be omitted.

Claim 1:
A transaxle device (<NUM>) for a hybrid vehicle (<NUM>) including an engine (<NUM>), a first rotating electric machine (<NUM>) having a cylindrical shape, and a second rotating electric machine (<NUM>) having a cylindrical shape and operable to individually transmit power of the engine (<NUM>) and power of the first rotating electric machine (<NUM>) to an output shaft (<NUM>) on a drive wheel (<NUM>) side from different power transmission paths and also to transmit the power of the engine (<NUM>) to the second rotating electric machine (<NUM>), the transaxle device (<NUM>) comprising:
a connection/disconnection mechanism (<NUM>', <NUM>'') which is provided on a first power transmission path (<NUM>) from the first rotating electric machine (<NUM>) to the output shaft (<NUM>) and enables or disables the transmission of the power of the first rotating electric machine (<NUM>);
a first rotating electric machine shaft (<NUM>) having a left side onto which the first rotating electric machine (<NUM>) is connected such that a bottom surface of the first rotating electric machine (<NUM>) faces a left side of the transaxle device (<NUM>);
a second rotating electric machine shaft (<NUM>) having a left side onto which the second rotating electric machine (<NUM>) is connected such that a bottom surface of the second rotating electric machine (<NUM>) faces the left side of the transaxle device (<NUM>);
a fixed gear (13a) which is provided on the first rotating electric machine shaft (<NUM>);
a counter shaft (<NUM>) which includes an idle gear (16c, 16d) normally engaging with the fixed gear (13a); and
a second fixed gear (16b) which is disposed on the counter shaft (<NUM>) and engaging with a ring gear (18a) of a differential (<NUM>), wherein
the connection/disconnection mechanism (<NUM>', <NUM>'') is provided on the counter shaft (<NUM>), and
the transaxle device (<NUM>) being characterized in that
the idle gear (16c, 16d) and the second fixed gear (16b) are disposed on the left side of the connection/disconnection mechanism (<NUM>', <NUM>''), and
wherein the number of teeth of the idle gear (16c, 16d) is larger than the number of teeth of the fixed gear (13a).