WO2012053142A1

WO2012053142A1 - Transmission

Info

Publication number: WO2012053142A1
Application number: PCT/JP2011/004613
Authority: WO
Inventors: Seiji Kuwahara
Original assignee: Toyota Jidosha Kabushiki Kaisha
Priority date: 2010-10-21
Filing date: 2011-08-18
Publication date: 2012-04-26

Abstract

A transmission (36) to be disposed between a rotating electric machine (22) serving as a power source of a vehicle and a drive wheel to transmit the rotation of an output shaft of the rotating electric machine (32) to the drive wheel while changing the speeds of the rotation of the output shaft of the rotating electric machine (32); comprising a planetary gear device (38) having an input member (28) and an output member (30), and a plurality of friction engagement devices (CI, C2, Bl, B2) for changing the power transmission states in the planetary gear device (38) to establish forward three- shift stages in response to the engagement states of the friction engagement devices (CI, C2, Bl, B2).

Description

TRANSMISSION

The present invention relates to a transmission that is applied to a vehicle provided with a rotating electric machine as a power source.

In general, a vehicle having a rotating electric machine as a power source mounted thereon has an output efficiency to the rotation number of the rotating electric machine, the output efficiency having a preferable property in a wide range as compared with an output efficiency to the rotation number of an internal combustion engine. This results in the fact that the drive force of the vehicle can be adjusted by varying an electric power to be supplied to the rotating electric machine without using any transmission.

For this reason, the vehicle having only one rotating electric machine as a power source mounted thereon is generally designed to transmit torque to drive wheels with no speed change by the transmission to the rotation of the output shaft of the rotating electric machine. A hybrid vehicle having the rotating electric machine and the internal combustion engine as a power source is adapted to transmit torque to the drive wheels through no transmission if the outputs of the rotating electric machine and the internal combustion engine are synthesized by a power splitting device.

The rotating electric machine has a rotation number range with the output efficiency being lowered that is not as remarkable as the internal combustion engine. Especially in the progress toward a high-capacity rotating electric machine, the efficiency to the rotation number becomes drastically changed as compared with the conventional low capacity rotating electric machine, thereby resulting in the situation necessarily not bringing about a high efficiency.

In view of this situation, it is known in the art that a transmission is to be mounted on a vehicle provided with such a rotating electric machine to vary the rotation speed of the output shaft of the rotating electric machine (see for example Patent Document 1).

The conventional transmission disclosed in the Patent Document 1 is applied to a vehicle having an internal combustion engine and a rotating electric machine connected in series as a power source, and adapted to conduct the speed change of the rotation of the output shaft of the rotating electric machine represented by the addition of the rotation numbers of the internal combustion engine and the rotating electric machine.

Such a transmission as described in the Patent Document 1 to be mounted on the vehicle is operative to adjust the rotation number of the rotating electric machine, thereby making it possible for the internal combustion engine to be used only in the range of the rotation number high in output efficiency as well as to vary the rotation number of the output shaft of the rotating electric machine. It is therefore possible to make narrow the rotation number area to be used in the rotating electric machine. This makes it possible to enhance not only the output efficiency of the internal combustion engine, but also the output efficiency of the rotating electric machine. Further, the rotation number of the output shaft of the rotating electric machine is the addition of the rotation numbers of the internal combustion engine and the rotating electric machine, so that the rotation number of the rotating electric machine can be lowered as compared with the case that only the rotating electric machine is mounted on the vehicle, thereby preventing the rotating electric machine from being operated in the high load state, and enhancing the durability of the rotating electric machine.

Here, the transmission to transmit torque to the drive wheels while varying the speed of the output rotation of the power source is generally constituted by a planetary gear device having a plurality of gears such as a sun gear, a ring gear, and a pinion gear. The gears constituting the planetary gear device tend to generate meshing loss while the gears are held in mesh with each other to be rotated.

{PTL 1}: Japanese Patent Laying-Open Publication No. H11(1999)-513878

However, the conventional transmission described in the Patent Document 1 as stated above is provided with a Ravigneaux type of planetary gear device to establish forward three-shift stages. This Ravigneaux type of planetary gear device is constituted by substantially two planetary mechanisms sharing one or more carrier.

Due to the two planetary mechanisms used although the smaller the number of gears constituting the transmission becomes, the smaller the power loss inputted into the transmission becomes, the number of gears intervening between the input member and the output member of the transmission is increased, thereby leading to the cause of increasing the loss to the output of the rotating electric machine.

In the case that the transmission is constituted by two planetary gears in place of the Ravigneaux type of planetary gear device, there is caused a necessity that the number of friction engagement devices be increased to change power transmission states in the planetary gear devices. For this reason, not only increased is the meshing loss similarly to the case that the Ravigneaux type of planetary gear device is used, but also increased is the drag loss, thereby leading to increase the loss to the output of the rotating electric machine.

The present invention has been made to solve the foregoing problems, and has an object to provide a transmission that can enhance the durability of an electric motor with a low loss.

For achieving the previously mentioned object, the transmission according to the present invention is characterized by a transmission to be disposed between a rotating electric machine serving as a power source of a vehicle and a drive wheel to transmit the rotation of an output shaft of the rotating electric machine to the drive wheel while changing the speeds of the rotation of the output shaft of the rotating electric machine; comprising a planetary gear device having an input member and an output member, and a plurality of friction engagement devices for changing the power transmission states in the planetary gear device to establish forward three-shift stages in response to the engagement states of the friction engagement devices.

By this construction, it is possible to establish a forward three-shift stages by changing the power transmission states of only one planetary gear device with a plurality of friction engagement devices. This makes it possible to reduce the number of gears for the power transmission and thus to lower the meshing loss as compared with the conventional transmission which is provided with a plurality of planetary gear devices to realize the forward three-shift stages. As a consequence, it is possible to realize a transmission that can enhance the power transmission efficiency.

It is preferable that at least any one of the forward three-shift stages functions as a backward movement stage when the output rotation of the rotating electric machine is reversely rotated.

By this construction, it is possible to allocate all the three-shift stages to the forward shift stages. Therefore, the output efficiency of the rotating electric machine can be enhanced without lowering the power transmission ratio of the transmission.

The transmission may further comprise an internal combustion engine serving as the power source, and in which the internal combustion engine and the rotating electric machine is mounted on the vehicle to be connected in series with each other through a power blocking device.

By this construction, it is possible to enhance the output efficiency of the rotating electric machine even in a hybrid vehicle having an internal combustion engine and a rotating electric machine as a power source.

The transmission may further comprise an internal combustion engine serving as the power source, and a power splitting device connected with the output shaft of the internal combustion engine, the output shaft of the rotating electric machine, and the input member.

It is preferable that the planetary gear device is constituted by a double pinion type of planetary gear having a sun gear, a ring gear, and a carrier differentially rotatable with one another, the output member being connected with the ring gear, the plurality of friction engagement devices being constituted by a first friction engagement device adapted to selectively have the input member connected to or disconnected from the sun gear, a second friction engagement device adapted to selectively have the input member connected to or disconnected from the carrier, a third friction engagement device adapted to selectively fix or release the sun gear, and a fourth friction engagement device adapted to selectively fix or release the carrier.

By this construction, it is possible to establish the forward three-shift stages in the transmission in response to the load and the vehicle speed of the vehicle. The rotating electric machine can be enhanced in efficiency and can be prevented from being operated in the high rotation state, thereby enhancing the durability of the rotating electric machine. Further, the forward three-shift stages and the backward one-shift stage can be accomplished only by one planetary gear and four friction engagement devices, thereby enabling the transmission to be downsized.

It is preferable that the planetary gear device is constituted by a double pinion type of planetary gear having a sun gear, a ring gear, and a carrier differentially rotatable with one another, the input member being connected with the ring gear, the plurality of friction engagement devices being constituted by a first friction engagement device adapted to selectively have the carrier connected to or disconnected from the output member, a second friction engagement device adapted to selectively have the sun gear connected to or disconnected from the output member, a third friction engagement device adapted to selectively fix or release the carrier, and a fourth friction engagement device adapted to selectively fix or release the sun gear.

It is preferable that the planetary gear device is constituted by a single pinion type of planetary gear having a sun gear, a ring gear, and a carrier differentially rotatable with one another, the plurality of friction engagement devices being constituted by a first friction engagement device adapted to selectively have the ring gear connected to or disconnected from the output member, a second friction engagement device adapted to selectively have the carrier connected to or disconnected from the output member, a third friction engagement device adapted to selectively have the input member connected to or disconnected from the carrier, and a fourth friction engagement device adapted to selectively have the input member connected to or disconnected from the sun gear, a fifth friction engagement device adapted to selectively fix or release the sun gear, and a sixth friction engagement device adapted to selectively fix or release the ring gear.

By this construction, it is possible to minimize the number of gears intervening between the input member and the output member of the transmission due to the construction of the single pinion type of planetary gear. This makes it possible to reduce the meshing loss to the power inputted from the rotating electric machine, and to enhance the power transmission efficiency between the input member and the output member.

It is preferable that the planetary gear device is constituted by a single pinion type of planetary gear having a sun gear, a ring gear, and a carrier differentially rotatable with one another, the plurality of friction engagement devices being constituted by a first friction engagement device adapted to selectively have the input member connected to or disconnected from the ring gear, a second friction engagement device adapted to selectively have the input member connected to or disconnected from the carrier, a third friction engagement device adapted to selectively have the carrier connected to or disconnected from the output member, and a fourth friction engagement device adapted to selectively have the sun gear connected to or disconnected from the output member, a fifth friction engagement device adapted to selectively fix or release the ring gear, and a sixth friction engagement device adapted to selectively fix or release the sun gear.

It is preferable that the planetary gear device is constituted by a single pinion type of planetary gear having a sun gear, a ring gear, and a carrier differentially rotatable with one another, the plurality of friction engagement devices being constituted by a first friction engagement device adapted to selectively have the input member connected to or disconnected from the carrier, a second friction engagement device adapted to selectively have the input member connected to or disconnected from the sun gear, a third friction engagement device adapted to selectively have the carrier connected to or disconnected from the output member, and a fourth friction engagement device adapted to selectively have the sun gear connected to or disconnected from the output member, and a fifth friction engagement device adapted to selectively fix or release the ring gear.

By this construction, it is possible to minimize the number of gears intervening between the input member and the output member of the transmission due to the construction of the single pinion type of planetary gear, to reduce the meshing loss to the power inputted from the rotating electric machine, and to realize a shift operation, i.e., a speed change operation, with five friction engagement devices, so that the drag loss resulting from the friction engagement devices can be lowered. Therefore, the power transmission efficiency between the input member and the output member can be enhanced.

According to the present invention, it is possible to provide a transmission that can enhance the durability of the rotating electric machine while maintaining the low loss.

FIG. 1 is a schematic constitution view of a vehicle having a control apparatus according to a first embodiment of the present invention to be mounted thereon. FIG. 2 is a skeleton view of a transmission according to the first embodiment of the present invention. FIG. 3 is an operation table of the transmission according to the first embodiment of the present invention. FIG. 4 is a collinear graph view of the transmission according to the first embodiment of the present invention. FIG. 5 is a schematic constitution view of another vehicle having the transmission according to the first embodiment of the present invention to be mounted thereon. FIG. 6 is a schematic constitution view of still another vehicle having the transmission according to the first embodiment of the present invention to be mounted thereon. FIG. 7 is a skeleton view of a transmission according to a second embodiment of the present invention. FIG. 8 is an operation table of the transmission according to the second embodiment of the present invention. FIG. 9 is a collinear graph view of the transmission according to the second embodiment of the present invention. FIG. 10 is a skeleton view of a transmission according to a third embodiment of the present invention. FIG. 11 is an operation table of the transmission according to the third embodiment of the present invention. FIG. 12 is a collinear graph view of the transmission according to the third embodiment of the present invention. FIG. 13 is a skeleton view of a transmission according to a fourth embodiment of the present invention. FIG. 14 is an operation table of the transmission according to the fourth embodiment of the present invention. FIG. 15 is a collinear graph view of the transmission according to the fourth embodiment of the present invention. FIG. 16 is a skeleton view of a transmission according to a fifth embodiment of the present invention. FIG. 17 is an operation table of the transmission according to the fifth embodiment of the present invention. FIG. 18 is a collinear graph view of the transmission according to the fifth embodiment of the present invention. FIG. 19 is a skeleton view of a transmission according to a first other embodiment of the present invention. FIG. 20 is an operation table of the transmission according to the first other embodiment of the present invention. FIG. 21 is a collinear graph view of the transmission according to the first other embodiment of the present invention. FIG. 22 is a skeleton view of a transmission according to a second other embodiment of the present invention. FIG. 23 is an operation table of the transmission according to the second other embodiment of the present invention. FIG. 24 is a collinear graph view of the transmission according to the second other embodiment of the present invention. FIG. 25 is a skeleton view of a transmission according to a third other embodiment of the present invention. FIG. 26 is an operation table of the transmission according to the third other embodiment of the present invention. FIG. 27 is a collinear graph view of the transmission according to the third other embodiment of the present invention. FIG. 28 is a skeleton view of a transmission according to a fourth other embodiment of the present invention. FIG. 29 is an operation table of the transmission according to the fourth other embodiment of the present invention. FIG. 30 is a collinear graph view of the transmission according to the fourth other embodiment of the present invention. FIG. 31 is a skeleton view of a transmission according to a fifth other embodiment of the present invention. FIG. 32 is an operation table of the transmission according to the fifth other embodiment of the present invention. FIG. 33 is a collinear graph view of the transmission according to the fifth other embodiment of the present invention. FIG. 34 is a skeleton view of a transmission according to a sixth other embodiment of the present invention. FIG. 35 is an operation table of the transmission according to the sixth other embodiment of the present invention. FIG. 36 is a collinear graph view of the transmission according to the sixth other embodiment of the present invention.

The embodiments of the present invention will hereinafter be described with reference to the drawings.

(First Embodiment)
FIG. 1 shows a vehicle 1 having a transmission 36 according to a first embodiment of the present invention to be mounted thereon. As shown in FIG. 1, the vehicle 1 comprises a motor generator 22 constituting a rotating electric machine, a transmission 36 connected with the motor generator 22 through its input member 28, a differential gear 32 connected with an output member 30 of the transmission 36,

drive shafts

33L, 33R connected with the differential gear 32, and left and right

front wheels

34L, 34R.

The left and right

front wheels

34L, 34R have a function as a steering wheel, and is adapted to be steered in response to the rotation of a steering wheel by a driver. The vehicle 1 further comprises left and right

rear wheels

35L, 35R having no drive power transmitted from the motor generator 22.

The vehicle 1 further comprises a battery 26 connected with the motor generator 22 through an inverter 24, and an electronic control unit 40 for controlling the motor generator 22 and the transmission 36.

The electronic control unit 40 is constituted by a known microprocessor provided with a CPU (Central Processing Unit) 42, a RAM (Random Access Memory) 44, a ROM (Read Only Memory) 46, and an input-output interface 48, and others all of which are connected with one another through a bi-directional bus.

The CPU 42 is designed to perform a signal processing in line with the program and the data preliminarily memorized in the ROM 46 while utilizing the temporal memory function of the RAM 44, thereby making it possible to execute various kinds of control such as an output control of the motor generator 22, a shift control, i.e., a speed change control, of the transmission 36, and the like.

The ROM 46 is adapted to memorize a speed change map relating to the vehicle speed and the accelerator opening degree correspondent to the shift stages of the transmission 36, and various kinds of process program.

The electronic control unit 40 is connected with an ignition switch 50, a shift position sensor 52, an accelerator opening degree sensor 54, a brake position sensor 56, and a vehicle speed sensor 58 through the input-output interface (I/F) 48 to be respectively inputted with an ignition signal, a shift position signal indicative of an operation position taken by a shift lever 51, an accelerator opening degree signal indicative of the depression amount of an accelerator pedal 53, a brake position signal indicative of the depression amount of a brake pedal 55.

The electronic control unit 40 is adapted to adjust the output of the motor generator 22 by controlling the inverter 24 based on the previously mentioned signals inputted through the input-output interface 48, and the shift stages established in the transmission 36. The electronic control unit 40 is adapted to decide the shift stages to be established in the transmission 36 with reference to the speed change map memorized in the ROM 46 when the vehicle speed signal and the accelerator opening degree signal are inputted in the electronic control unit 40. The electronic control unit 40 is adapted to change the engagement states of a first clutch C1, a second clutch C2, a first brake B1, and a second brake B2, to be described hereinafter, through a hydraulic control circuit not shown to establish an optimum shift stage in response to the cruising state of the vehicle.

In the present embodiment, the shift lever 51 operated by a driver for the vehicle to move forward makes it possible for the electronic control unit 40 to be operated to establish any one of the shift stages from the first shift stage (1st) to the third shift stage (3rd) in the transmission 36. On the other hand, the shift lever 51 operated by a driver for the vehicle to move backward makes it possible for the electronic control unit 40 to be operated to rotate the motor generator 22 in an opposite direction to the forward movement of the vehicle as well as to establish the forward first shift stage in the transmission 36 at the forward movement of the vehicle. This results in the fact that the electronic control unit 40 can normally establish the first shift stage in the transmission 36 at the time of the vehicle 1 reducing the cruising speed to stop, thereby preferably making it unnecessary for the shift control, i.e., the speed change control, to be executed at the time of the stop state transferring to the backward movement of the vehicle.

As shown in FIG. 2, the transmission 36 has a double pinion type of planetary gear 38, a first clutch C1, a second clutch C2, a first brake B1, and a second brake B2, which are all accommodated in a transmission case not shown.

The first clutch C1, the second clutch C2, the first brake B1, and the second brake B2 each partly constitute a hydraulic friction engagement device which is to be operated by a hydraulic actuator through a hydraulic control circuit not shown to have the above clutches and the brakes frictionally engageable. Here, the first clutch C1, the second clutch C2, the first brake B1, and the second brake B2 constitute as a whole a plurality of friction engagement devices in the present invention.

The input member 28 is selectively connected with or disconnected from a sun gear S through the first clutch C1, and selectively connected with or disconnected from a carrier CA through the second clutch C2. The output member 30 is connected with a ring gear R.

The first brake B1 is adapted to selectively fix or release the sun gear S. The second brake B2 is adapted to selectively fix or release the carrier CA.

FIG. 3 is an operation table of the transmission 36. In FIG. 3, the symbol "O" is representative of the engagement state of each friction engagement device, while no symbol is representative of the released state of each friction engagement device. The symbol of the Greek alphabet "lambda" (hereinafter simply referred to as "lambda") is representative of a gear ratio of the gear number of the sun gear S to the gear number of the ring gear R. The gear ratio "lambda" can be set to be 0 < "lambda" < 1, and preferably has a value of more than 0.3 and below 0.7 selected as a planetary gear used in the transmission 36.

Firstly, explanation will be made hereinafter about the case of the gear ratio of "lambda" < 0.5.

For establishing the forward first shift stage, the electronic control unit 40 is operative to have the first clutch C1 and the second brake B2 brought into the engagement state. At this time, the rotation speed of the output member 30 to the rotation speed of the input member 28 is "lambda", while the gear ratio is 1/"lambda".

For establishing the forward second shift stage, the electronic control unit 40 is operative to have the second clutch C2 and the first brake B1 brought into the engagement state. At this time, the rotation speed of the output member 30 to the rotation speed of the input member 28 is 1 - "lambda", while the gear ratio is 1/(1 - "lambda").

Further, for establishing the forward third shift stage, the electronic control unit 40 is operative to have the first clutch C1 and the second clutch C2 brought into the engagement state. At this time, both the rotation speed of the output member 30 to the rotation speed of the input member 28, and the gear ratio come to be 1.

FIG. 4 is a collinear graph view of the transmission 36 for executing the speed change as previously mentioned. For better understanding about the collinear graph views in the following embodiments including the present embodiment, the rotation speeds of the motor generator 22 in the shift stages are set to be equal to one another.

When the forward first shift stage is firstly established in the transmission 36, the second brake B2 is brought into the engagement state, and thus the carrier CA is fixed (see solid line 1st). The rotation number of the output member 30 at this time is given by the point "A". When the forward second shift stage is then established in the transmission 36, the sun gear is fixed (see solid line 2nd) by the first brake B1. The rotation speed of the output member 30 at this time is given by the point "B". When the forward third shift stage is then established in the transmission 36, the first clutch C1 and the second clutch C2 are brought into the engagement state, and thus the sun gear, the carrier, and the ring gear are rotated at the same rotation speed (see solid line 3rd). The rotation speed of the output member 30 at this time is given by the point "C".

At the time of the backward movement of the vehicle 1, the electronic control unit 40 is operative to have the first clutch C1 and the second brake B2 brought into the engagement state similarly to the forward first shift stage of the vehicle 1, and to have the output shaft of the motor generator 22 reversely rotated. The electronic control unit 40 may be operative to have the output shaft of the motor generator 22 reversely rotated under the established states of the forward second shift stage or the forward third shift stage at the time of the backward movement of the vehicle 1.

Then, explanation will be made hereinafter about the case of the gear ratio of "lambda" > 0.5.

As shown in FIG. 3, the electronic control unit 40 is operative to have the second clutch C2 and the first brake B1 brought into the engagement state for establishing the forward first shift stage. At this time, the rotation speed of the output member 30 to the rotation speed of the input member 28 is 1 - "lambda", while the gear ratio is 1/(1 - "lambda").

Further, the electronic control unit 40 is operative to have the first clutch C1 and the second brake B2 brought into the engagement state for establishing the forward second shift stage. At this time, the rotation speed of the output member 30 to the rotation speed of the input member 28 is "lambda", while the gear ratio is 1/"lambda".

Further, the electronic control unit 40 is operative to have the first clutch C1 and the second clutch C2 brought into the engagement state for establishing the forward third shift stage. At this time, both the rotation speed of the output member 30 to the rotation speed of the input member 28, and the gear ratio come to be 1.

The collinear graph view of the transmission 36 for executing the speed change as previously mentioned is shown in FIG. 4.

When the forward first shift stage is firstly established in the transmission 36, the first brake B1 is brought into the engagement state, and thus the sun gear S is fixed (see solid line 1st). The rotation number of the output member 30 at this time is given by the point "A". When the forward second shift stage is then established in the transmission 36, the carrier CA is fixed (see solid line 2nd) by the second brake B2. The rotation speed of the output member 30 at this time is given by the point "B". When the forward third shift stage is then established in the transmission 36, the first clutch C1 and the second clutch C2 are brought into the engagement state, and thus the sun gear, the carrier, and the ring gear are rotated at the same rotation speed (see solid line 3rd). The rotation speed of the output member 30 at this time is given by the point "C".

Further, at the time of the backward movement of the vehicle 1, the electronic control unit 40 is operative to have the second clutch C2 and the first brake B1 brought into the engagement state similarly to the forward first shift stage, and to have the output shaft of the motor generator 22 reversely rotated. The electronic control unit 40 may be operative to have the output shaft of the motor generator 22 reversely rotated under the established states of the forward second shift stage or the forward third shift stage at the time of the backward movement of the vehicle 1.

As will be understood from the foregoing description, the transmission 36 according to the first embodiment of the present invention can realize the establishment of the forward three-shift stages by changing the power transmission states of one planetary gear 38 with four friction engagement devices. This makes it possible to reduce the number of gears assembled in the power transmission, thereby lowering the gear meshing loss as compared with the conventional transmission by providing the plurality of planetary gears to realize the establishment of the forward three-shift stages. As a consequence, the present invention can realize a transmission improved in power transmission efficiency.

Further, the present invention can establish the forward three-shift stages in the transmission 36 in response to the load and the vehicle speed of the vehicle 1, so that the motor generator 22 can be enhanced in efficiency and can be prevented from being operated in the high rotation state, thereby enhancing the durability of the motor generator 22. Further, the forward three-shift stages and the backward one-shift stage can be accomplished only by one planetary gear 38 and four friction engagement devices, thereby enabling the transmission 36 to be downsized.

Further, only one planetary gear 38 makes it possible to allocate all the three-shift stages to the forward shift stages. Therefore, the output efficiency of the motor generator 22 can be enhanced without lowering the power transmission efficiency of the transmission 36.

Further, the previous explanation has been made about the case that the transmission 36 having only the motor generator 22 as a power source is mounted on the vehicle 1 as shown in FIG. 1; however, the transmission 36 according to the present embodiment may have an engine 62 in addition to the motor generator 22 as a power source to be mounted on a vehicle 60 as shown in FIG. 5. In this case, the engine 62 and the motor generator 22 are constructed to be connected with a known power splitting device 65 constituted by a planetary gear and other components. The transmission 36 is set to change the rotation speed of the output shaft of the power splitting device 65.

By the construction as described hereinbefore, in the hybrid vehicle having the engine 62 and the motor generator 22 serving as the power source connected with each other by the power splitting device 65, the rotation number of the power splitting device 65 can be varied, thereby enabling the output efficiency of the motor generator 22 to be enhanced.

As shown in FIG. 6, the transmission 36 according to the present embodiment may have the engine 62 and the motor generator 22 serve as the power source and may be mounted on a vehicle 67 with the engine 62 and the motor generator 22 being connected in series with each other. In this case, the transmission 36 is constructed to have the output shaft of the motor generator 22 variably rotated. Between the engine 62 and the motor generator 22 is arranged a clutch 68 operative in a released state in which the motor generator 22 is reversely rotated for the backward movement of the vehicle 67.

By the construction as described hereinbefore, in the hybrid vehicle having the engine 62 and the motor generator 22 connected in series with each other through the clutch 68, the rotation number of the output shaft of the motor generator 22 can be varied, thereby enabling the output efficiency of the motor generator to be enhanced.

(Second Embodiment)
The transmission 71 according to the second embodiment of the present invention will be explained hereinafter with reference to FIGS. 7 to 9.

The transmission 71 according to the second embodiment will be explained using the reference numerals the same as those of the transmission 36 according to the first embodiment in FIGS. 1 to 4 for the constitution elements or parts the same as those of the transmission 36 according to the first embodiment, and particularly stating only about the different aspects.

Although there will be explained hereinafter about the transmission 71 according to the second embodiment to be mounted on the vehicle 1 shown in FIG. 1, the transmission 71 may be mounted on the vehicle 60 shown in FIG. 5 or on the vehicle 67 shown in FIG. 6 similarly to the transmission 36 according to the first embodiment.

As shown in FIG. 7, the transmission 71 according to the present embodiment has a double pinion type of planetary gear 38, a first clutch C1, a second clutch C2, a first brake B1, and a second brake B2, which are all accommodated in a transmission case not shown.

Here, the first clutch C1, the second clutch C2, the first brake B1, and the second brake B2 in the present embodiment constitute as a whole a plurality of friction engagement devices in the present invention.

The input member 28 is connected with a ring gear R. The output member 30 is selectively connected with or disconnected from a carrier CA through the first clutch C1, and selectively connected with or disconnected from a sun gear S through the second clutch C2.

The first brake B1 is adapted to selectively fix or release the carrier CA, while the second brake B2 is adapted to selectively fix or release the sun gear S.

FIG. 8 is an operation table of the transmission 71. Explanation will be made hereinafter about the case of the gear ratio of "lambda" < 0.5.

For establishing the forward first shift stage, the electronic control unit 40 is operative to have the first clutch C1 and the second clutch C2 brought into the engagement state. At this time, both the rotation speed of the output member 30 to the rotation speed of the input member 28, and the gear ratio come to be 1.

For establishing the forward second shift stage, the electronic control unit 40 is operative to have the first clutch C1 and the second brake B2 brought into the engagement state. At this time, the rotation speed of the output member 30 to the rotation speed of the input member 28 is 1/(1 - "lambda"), while the gear ratio is 1 - "lambda".

Further, for establishing the forward third shift stage, the electronic control unit 40 is operative to have the second clutch C2 and the first brake B1 brought into the engagement state. At this time, the rotation speed of the output member 30 to the rotation speed of the input member 28 is 1/"lambda", while the gear ratio is "lambda".

The collinear graph view of the transmission 71 for executing the speed change as previously mentioned is shown in FIG. 9. For better understanding about the collinear graph views in the following embodiments, the rotation speeds of the motor generator 22 in the shift stages are set to be equal to one another.

When the forward first shift stage is firstly established in the transmission 71, the first clutch C1 and the second clutch C2 are brought into the engagement state so that the sun gear, the carrier, and the ring gear are rotated at the same rotation speed (see solid line 1st). The rotation number of the output member 30 at this time is given by the point "A".

When the forward second shift stage is then established in the transmission 71, the sun gear is fixed (see solid line 2nd) by the second brake B2. The rotation speed of the output member 30 at this time is given by the point "B".

When the forward third shift stage is then established in the transmission 36, the first brake B1 is brought into the engagement state, and thus the carrier CA is fixed (see solid line 3rd). The rotation speed of the output member 30 at this time is given by the point "C".

At the time of the backward movement of the vehicle 1, the electronic control unit 40 is operative to have the first clutch C1 and the second clutch C2 brought into the engagement state similarly to the forward first shift stage, and to have the output shaft of the motor generator 22 reversely rotated. The electronic control unit 40 may be operative to have the output shaft of the motor generator 22 reversely rotated under the established states of the forward second shift stage or the forward third shift stage at the time of the backward movement of the vehicle 1.

As shown in FIG. 8, the electronic control unit 40 is operative to have the first clutch C1 and the second clutch C2 brought into the engagement state for establishing the forward first shift stage. At this time, both the rotation speed of the output member 30 to the rotation speed of the input member 28, and the gear ratio come to be 1.

Further, the electronic control unit 40 is operative to have the second clutch C2 and the first brake B1 brought into the engagement state for establishing the forward second shift stage. At this time, the rotation speed of the output member 30 to the rotation speed of the input member 28 is 1/"lambda", while the gear ratio is "lambda".

Further, the electronic control unit 40 is operative to have the first clutch C1 and the second brake B2 brought into the engagement state for establishing the forward third shift stage. At this time, the rotation speed of the output member 30 to the rotation speed of the input member 28 is 1/(1 - "lambda"), while the gear ratio is 1 - "lambda".

The collinear graph view of the transmission 36 for executing the speed change as previously mentioned is shown in FIG. 9.

When the forward first shift stage is firstly established in the transmission 71, the first clutch C1 and the second clutch C2 are brought into the engagement state so that the sun gear, the carrier, and the ring gear are rotated at the same rotation speed (see solid line 1st). The rotation number of the output member 30 at this time is given by the point "A". When the forward second shift stage is then established in the transmission 71, the carrier CA is fixed (see solid line 2nd) by the first brake B1. The rotation speed of the output member 30 at this time is given by the point "B". When the forward third shift stage is then established in the transmission 71, the second brake B2 is brought into the engagement state, and thus the sun gear S is fixed (see solid line 3rd). The rotation speed of the output member 30 at this time is given by the point "C".

Further, at the time of the backward movement of the vehicle 1, the electronic control unit 40 is operative to have the first clutch C1 and the second clutch C2 brought into the engagement state similarly to the forward first shift stage, and to have the output shaft of the motor generator 22 reversely rotated. The electronic control unit 40 may be operative to have the output shaft of the motor generator 22 reversely rotated under the established states of the forward second shift stage or the forward third shift stage at the time of the backward movement of the vehicle 1.

As will be understood from the foregoing description, the transmission 71 according to the second embodiment of the present invention can realize the establishment of the forward three-shift stages in response to the load and the vehicle speed of the vehicle 1, so that the efficiency of the motor generator 22 can be enhanced, and the durability of the motor generator 22 can be enhanced by preventing the motor generator 22 from being operated in the high rotation state. Further, the forward three-shift stages and the backward one-shift stage can be accomplished only by one planetary gear 38 and four friction engagement devices, thereby enabling the transmission 71 to be downsized.

(Third Embodiment)
The transmission 73 according to the third embodiment of the present invention will be explained hereinafter with reference to FIGS. 10 to 12.

The transmission 73 according to the third embodiment will be explained using the reference numerals the same as those of the transmission 36 according to the first embodiment in FIGS. 1 to 4 for the constitution elements or parts the same as those of the transmission 36 according to the first embodiment, and particularly stating only about the different aspects.

Although there will be explained hereinafter about the transmission 73 according to the third embodiment to be mounted on the vehicle 1 shown in FIG. 1, the transmission 73 may be mounted on the vehicle 60 shown in FIG. 5 or on the vehicle 67 shown in FIG. 6 similarly to the transmission 36 according to the first embodiment.

As shown in FIG. 10, the transmission 73 according to the present embodiment has a single pinion type of planetary gear 41, a first clutch C1, a second clutch C2, a third clutch C3, a fourth clutch C4, a first brake B1, and a second brake B2, which are all accommodated in a transmission case not shown.

Here, the first clutch C1, the second clutch C2, the third clutch C3, the fourth clutch C4, the first brake B1, and the second brake B2 in the present embodiment constitute as a whole a plurality of friction engagement devices in the present invention.

The input member 28 is selectively connected with or disconnected from a sun gear S through the fourth clutch C4, and connected with a carrier CA through the third clutch C3.

The output member 30 is selectively connected with or disconnected from a ring gear R through the first clutch C1, and selectively connected with or disconnected from the carrier CA through the second clutch C2.

The first brake B1 is adapted to selectively fix or release the sun gear S, while the second brake B2 is adapted to selectively fix or release the ring gear R.

FIG. 11 is an operation table of the transmission 73.

For establishing the forward first shift stage, the electronic control unit 40 is operative to have the second clutch C2, the fourth clutch C4, and the second brake B2 brought into the engagement state. At this time, the rotation speed of the output member 30 to the rotation speed of the input member 28 is "lambda"/(1 + "lambda"), while the gear ratio is (1 + "lambda")/"lambda".

For establishing the forward second shift stage, the electronic control unit 40 is operative to execute any one of the following control operations. Firstly, the first control operation is carried out to have the first clutch C1, the second clutch C2, the third clutch C3, and the fourth clutch C4 brought into the engagement state to establish 2nd (a) shown in the operation table. Or otherwise, the second control operation is carried out to have the second clutch C2, the third clutch C3, and the fourth clutch C4 brought into the engagement state to establish 2nd (b) shown in the operation table. Or otherwise, the third control operation is carried out to have the first clutch C1, the third clutch C3, and the fourth clutch C4 brought into the engagement state to establish 2nd (c) shown in the operation table. Or otherwise, the fourth control operation is carried out to have the first clutch C1, the second clutch C2, and the fourth clutch C4 brought into the engagement state to establish 2nd (d) shown in the operation table.

In the case that any one of the first to fourth control operations is carried out, both the rotation speed of the output member 30 to the rotation speed of the input member 28, and the gear ratio come to be 1.

Here, in the case of carrying out the upshift operation from the forward first shift stage to the forward second shift stage, the electronic control unit 40 is operative to have the above second control operation carried out to establish the forward second shift stage in the transmission 73. In the case that the vehicle 1 is further under acceleration, the electronic control unit 40 is operative to shift the above second control operation to the third control operation. In the case of carrying out the upshift operation to the forward third shift stage from the above stage, the electronic control unit 40 is operative to control the transmission 73 from the established 2nd (c) state.

By carrying out the control operations as previously mentioned, the electronic control unit 40 is operative for the transfer from the forward first shift stage to the forward second shift stage to release the second brake B2 and to engage the third clutch C3, thereby enabling the upshift operation with clutch-to-clutch shift. In addition, the electronic control unit 40 is operative for the transfer from the forward second shift stage to the forward third shift stage to release the fourth clutch C4 and to engage the first brake B1 for the transfer from the forward second shift stage to the forward third shift stage, thereby enabling the upshift operation with clutch-to-clutch shift. The electronic control unit 40 operative to perform the clutch-to-clutch shift can result in easily realizing the shift operations as compared with the case that more than three friction engagement devices are controlled to carry out the shift operation.

Similarly, the electronic control unit 40 is operative to have the above third control operation carried out to establish the forward second shift stage in the case of the transfer from the forward third shift stage to the forward second shift stage in the transmission 73. Under the further speed reduction of the vehicle 1, the electronic control unit 40 is operative to be changed from the above third control operation to the second control operation, and the electronic control unit 40 is operative to control the transmission 73 from the 2nd (b) state for the downshift to the forward first shift stage.

Further, for establishing the forward third shift stage, the electronic control unit 40 is operative to have the first clutch C1, the third clutch C3, and the first brake B1 brought into the engagement state. At this time, the rotation speed of the output member 30 to the rotation speed of the input member 28 is 1 + "lambda", while the gear ratio is 1/(1 + "lambda").

The collinear graph view of the transmission 73 for executing the speed change as previously mentioned is shown in FIG. 12.

When the forward first shift stage is firstly established in the transmission 73, the ring gear R is fixed (see solid line 1st) by the second brake B2. The rotation number of the output member 30 at this time is given by the point "A". When the forward third shift stage is then established in the transmission 73, the above second control operation is carried out to have the second clutch C2, the third clutch C3, and the fourth clutch C4 brought into the engagement state, so that the sun gear, the carrier, and the ring gear are rotated at the same rotation speed (see solid line 2nd). The rotation number of the output member 30 at this time is given by the point "B".

When the forward third shift stage is then established in the transmission 73, the first brake B1 is brought into the engagement state, and thus the sun gear S is fixed (see solid line 3rd). The rotation number of the output member 30 at this time is given by the point "C".

At the time of the backward movement of the vehicle 1, the electronic control unit 40 is operative to have the second clutch C2, the fourth clutch C4, and the second brake B2 brought into the engagement state in a similar manner to the case of the forward first shift stage, and to have the output shaft of the motor generator 22 reversely rotated. The electronic control unit 40 may be operative to have the output shaft of the motor generator 22 reversely rotated under the established states of the forward second shift stage and the forward third shift stage at the time of the backward movement of the vehicle 1.

As will be understood from the foregoing description, the transmission 73 according to the third embodiment of the present invention is partly constituted by the single pinion type of planetary gear 41, so that the number of gears intervening between the input member 28 and the output member 30 can be minimized. This makes it possible to reduce the meshing loss to the power inputted from the motor generator 22 and to enhance the power transmission efficiency between the input member 28 and the output member 30.

(Fourth Embodiment)
The transmission 75 according to the fourth embodiment of the present invention will be explained hereinafter with reference to FIGS. 13 to 15.

The transmission 75 according to the fourth embodiment will be explained using the reference numerals the same as those of the transmission 36 according to the first embodiment in FIGS. 1 to 4 for the constitution elements or parts the same as those of the transmission 36 according to the first embodiment, and particularly stating only about the different aspects.

Although there will be explained hereinafter about the transmission 75 according to the fourth embodiment to be mounted on the vehicle 1 shown in FIG. 1, the transmission 75 may be mounted on the vehicle 60 shown in FIG. 5 or on the vehicle 67 shown in FIG. 6 similarly to the transmission 36 according to the first embodiment.

As shown in FIG. 13, the transmission 75 according to the present embodiment has a single pinion type of planetary gear 41, a first clutch C1, a second clutch C2, a third clutch C3, a fourth clutch C4, a first brake B1, and a second brake B2, which are all accommodated in a transmission case not shown.

The input member 28 is selectively connected with or disconnected from a ring gear through the first clutch C1, and selectively connected with or disconnected from a carrier CA through the second clutch C2.

The output member 30 is selectively connected with or disconnected from the carrier CA through the third clutch C3, and selectively connected with or disconnected from the sun gear S through the fourth clutch C4.

FIG. 14 is an operation table of the transmission 75.

For establishing the forward first shift stage, the electronic control unit 40 is operative to have the first clutch C1, the third clutch C3, and the first brake B1 brought into the engagement state. At this time, the rotation speed of the output member 30 to the rotation speed of the input member 28 is 1/(1 + "lambda"), while the gear ratio is 1 + "lambda".

Here, in the case of carrying out the upshift operation from the forward first shift stage to the forward second shift stage, the electronic control unit 40 is operative to have the above third control operation carried out to establish the forward second shift stage in the transmission 75. In the case that the vehicle 1 is further under acceleration, the electronic control unit 40 is operative to shift the above third control operation to the fourth control operation. In the case of carrying out the upshift operation to the forward third shift stage from the above stage, the electronic control unit 40 is operative to control the transmission 75 from the established 2nd (d) state.

By carrying out the control operations as previously mentioned, the electronic control unit 40 is operative for the transfer from the forward first shift stage to the forward second shift stage to release the first brake B1 and to engage the fourth clutch C4, thereby enabling the upshift operation with clutch-to-clutch shift. In addition, the electronic control unit 40 is operative for the transfer from the forward second shift stage to the forward third shift stage to release the first clutch C1 and to engage the second brake B2, thereby enabling the upshift operation with clutch-to-clutch shift. The electronic control unit 40 operative to perform the clutch-to-clutch shift can result in easily realizing the shift operations as compared with the case that more than three friction engagement devices are controlled to carry out the shift operations.

Similarly, the electronic control unit 40 is operative, in the case of the transfer from the forward third shift stage to the forward second shift stage, to have the above fourth control operation carried out to establish the forward second shift stage in the transmission 75. Under the further speed reduction of the vehicle 1, the electronic control unit 40 is operative to be changed from the above fourth control operation to the third control operation, and the electronic control unit 40 is operative to control the transmission 75 from the 2nd (c) state for the downshift to the forward first shift stage.

Further, for establishing the forward third shift stage, the electronic control unit 40 is operative to have the second clutch C2, the fourth clutch C4, and the second brake B2 brought into the engagement state. At this time, the rotation speed of the output member 30 to the rotation speed of the input member 28 is (1 + "lambda")/"lambda", while the gear ratio is "lambda"/(1 + "lambda").

The collinear graph view of the transmission 75 for executing the speed change as previously mentioned is shown in FIG. 15.

When the forward first shift stage is firstly established in the transmission 75, the sun gear S is fixed (see solid line 1st) by the first brake B1. The rotation number of the output member 30 at this time is given by the point "A".

When the forward third shift stage is then established in the transmission 75, the above third control operation is carried out to have the first clutch C1, the third clutch C3, and the fourth clutch C4 brought into the engagement state, so that the sun gear, the carrier, and the ring gear are rotated at the same rotation speed (see solid line 2nd). The rotation number of the output member 30 at this time is given by the point "B".

When the forward third shift stage is then established in the transmission 75, the second brake B2 is brought into the engagement state, and thus the ring gear R is fixed (see solid line 3rd). The rotation number of the output member 30 at this time is given by the point "C".

At the time of the backward movement of the vehicle 1, the electronic control unit 40 is operative to have the first clutch C1, the third clutch C3, and the first brake B1 brought into the engagement state in a similar manner to the case of the forward first shift stage, and to have the output shaft of the motor generator 22 reversely rotated. The electronic control unit 40 may be operative to have the output shaft of the motor generator 22 reversely rotated under the established states of the forward second shift stage or the forward third shift stage at the time of the backward movement of the vehicle 1.

As will be understood from the foregoing description, the transmission 75 according to the fourth embodiment of the present invention is partly constituted by the single pinion type of planetary gear 41, so that the number of gears intervening between the input member 28 and the output member 30 can be minimized. This makes it possible to reduce the meshing loss to the power inputted from the motor generator 22 and to enhance the power transmission efficiency between the input member 28 and the output member 30.

(Fifth Embodiment)
The transmission 77 according to the fifth embodiment of the present invention will be explained hereinafter with reference to FIGS. 16 to 18.

The transmission 77 according to the fifth embodiment will be explained using the reference numerals the same as those of the transmission 36 according to the first embodiment in FIGS. 1 to 4 for the constitution elements or parts the same as those of the transmission 36 according to the first embodiment, and particularly stating only about the different aspects.

Although there will be explained hereinafter about the transmission 77 according to the fifth embodiment to be mounted on the vehicle 1 shown in FIG. 1, the transmission 77 may be mounted on the vehicle 60 shown in FIG. 5 or on the vehicle 67 shown in FIG. 6 similarly to the transmission 36 according to the first embodiment.

As shown in FIG. 16, the transmission 77 according to the present embodiment has a single pinion type of planetary gear 41, a first clutch C1, a second clutch C2, a third clutch C3, a fourth clutch C4, and a first brake B1, which are all accommodated in a transmission case not shown.

Here, the first clutch C1, the second clutch C2, the third clutch C3, the fourth clutch C4, and the first brake B1 in the present embodiment constitute as a whole a plurality of friction engagement devices in the present invention.

The input member 28 is selectively connected with or disconnected from a carrier CA through the first clutch C1, and selectively connected with or disconnected from a sun gear S through the second clutch C2.

The first brake B1 is adapted to selectively fix or release the ring gear R.

FIG. 17 is an operation table of the transmission 77.

For establishing the forward first shift stage, the electronic control unit 40 is operative to have the second clutch C2, the third clutch C3, and the first brake B1 brought into the engagement state. At this time, the rotation speed of the output member 30 to the rotation speed of the input member 28 is "lambda"/(1 + "lambda"), while the gear ratio is (1 + "lambda")/"lambda".

For establishing the forward second shift stage, the electronic control unit 40 is operative to execute any one of the following control operations. Firstly, the first control operation is carried out to have the first clutch C1, the second clutch C2, the third clutch C3, and the fourth clutch C4 brought into the engagement state to establish 2nd (a) shown in the operation table. Or otherwise, the second control operation is carried out to have the first clutch C1, the second clutch C2, and the fourth clutch C4 brought into the engagement state to establish 2nd (b) shown in the operation table. Or otherwise, the third control operation is carried out to have the first clutch C1, the third clutch C3, and the fourth clutch C4 brought into the engagement state to establish 2nd (c) shown in the operation table. Or otherwise, the fourth control operation is carried out to have the second clutch C2, the third clutch C3, and the fourth clutch C4 brought into the engagement state to establish 2nd (d) shown in the operation table.

Here, in the case of carrying out the upshift operation from the forward first shift stage to the forward second shift stage, the electronic control unit 40 is operative to have the above fourth control operation carried out to establish the forward second shift stage in the transmission 77. In the case that the vehicle 1 is further under acceleration, the electronic control unit 40 is operative to shift the above fourth control operation to the third control operation for the upshift operation to the forward third shift stage from the above stage. In this case, the electronic control unit 40 is operative to control the transmission 77 from the established 2nd (c) state.

By carrying out the control operations as previously mentioned, the electronic control unit 40 is operative for the transfer from the forward first shift stage to the forward second shift stage to release the first brake B1 and to engage the fourth clutch C4, thereby enabling the upshift operation with clutch-to-clutch shift. In addition, the electronic control unit 40 is operative for the transfer from the forward second shift stage to the forward third shift stage to release the third clutch C3 and to engage the first brake B1, thereby enabling the upshift operation with clutch-to-clutch shift. The electronic control unit 40 operative to perform the clutch-to-clutch shift can result in easily realizing the shift operations as compared with the case that more than three friction engagement devices are controlled to carry out the shift operations.

Similarly, the electronic control unit 40 is operative, in the case of the transfer from the forward third shift stage to the forward second shift stage, to have the above third control operation carried out to establish the forward second shift stage in the transmission 77. Under the further speed reduction of the vehicle 1, the electronic control unit 40 is operative to be changed from the above third control operation to the fourth control operation, and the electronic control unit 40 is operative to control the transmission 77 from the 2nd (d) state for the downshift to the forward first shift stage.

Further, for establishing the forward third shift stage, the electronic control unit 40 is operative to have the first clutch C1, the fourth clutch C4, and the first brake B1 brought into the engagement state. At this time, the rotation speed of the output member 30 to the rotation speed of the input member 28 is (1 + "lambda")/"lambda", while the gear ratio is "lambda"/(1 + "lambda").

The collinear graph view of the transmission 77 for executing the speed change as previously mentioned is shown in FIG. 18.

When the forward first shift stage is firstly established in the transmission 77, the ring gear R is fixed (see solid line 1st) by the first brake B1. The rotation number of the output member 30 at this time is given by the point "A".

When the forward second shift stage is then established in the transmission 77, the above second control operation is carried out to have the second clutch C2, the third clutch C3, and the fourth clutch C4 brought into the engagement state, so that the sun gear, the carrier, and the ring gear are rotated at the same rotation speed (see solid line 2nd). The rotation number of the output member 30 at this time is given by the point "B".

When the forward third shift stage is then established in the transmission 77, the first brake B1 is brought into the engagement state, and thus the ring gear R is fixed (see solid line 3rd). The rotation number of the output member 30 at this time is given by the point "C".

At the time of the backward movement of the vehicle 1, the electronic control unit 40 is operative to have the second clutch C2, the third clutch C3, and the first brake B1 brought into the engagement state in a similar manner to the case of the forward first shift stage, and to have the output shaft of the motor generator 22 reversely rotated. The electronic control unit 40 may be operative to have the output shaft of the motor generator 22 reversely rotated under the established states of the forward second shift stage or the forward third shift stage at the time of the backward movement of the vehicle 1.

As will be understood from the foregoing description, the transmission 77 according to the fifth embodiment of the present invention is partly constituted by the single pinion type of planetary gear 41, so that the number of gears intervening between the input member 28 and the output member 30 can be minimized. This makes it possible to reduce the meshing loss to the power inputted from the motor generator 22 and to realize the shift operation with five friction engagement devices, so that the drag loss resulting from the friction engagement devices can be lowered. Therefore, the power transmission efficiency between the input member 28 and the output member 30 can be enhanced.

Further, the above explanation has been directed to the case that the transmission is provided with one planetary gear and four to six friction engagement devices to establish the forward first to third shift stages and the backward movement stage. However, the present invention may be constructed to have the transmission provided with one planetary gear and two friction engagement devices to establish the forward first and second shift stages and the backward movement stage as will be understood from the first to sixth other construction examples as follows.

The first to sixth other construction examples of the transmission according to the present invention will be explained with reference to FIGS. 19 to 36.

The first to sixth other construction examples of the transmission will be explained using the reference numerals the same as those of the transmission 36 according to the first embodiment in FIGS. 1 to 4 for the constitution elements or parts the same as those of the transmission 36 according to the first embodiment, and particularly stating only about the different aspects. Although there will be explained hereinafter about the transmission to be mounted on the vehicle 1 shown in FIG. 1, the transmission may be mounted on the vehicle 60 or on the vehicle 67 similarly to the transmission according to the first to fifth embodiments.

(First Other Construction Example)
The first other construction example of the transmission according to the present invention will be explained hereinafter with reference to FIGS. 19 to 21.

As shown in FIG. 19, the transmission 79 has a double pinion type of planetary gear 38, a first clutch C1, and a first brake B1, which are accommodated in a transmission case not shown.

The input member 28 is connected with a sun gear S, and selectively connected with or disconnected from a carrier CA through the first clutch C1. The output member 30 is connected with a ring gear R. The first brake B1 is adapted to selectively fix or release the carrier CA.

FIG. 20 is an operation table of the transmission 79. For establishing the forward first shift stage, the electronic control unit 40 is operative to have the first brake B1 brought into the engagement state. At this time, the rotation speed of the output member 30 to the rotation speed of the input member 28 is "lambda", while the gear ratio is 1/"lambda".

For establishing the forward second shift stage, the electronic control unit 40 is operative to have the first clutch C1 brought into the engagement state. At this time, both the rotation speed of the output member 30 to the rotation speed of the input member 28, and the gear ratio come to be 1.

The collinear graph view of the transmission 79 for executing the speed change as previously mentioned is shown in FIG. 21.

When the forward first shift stage is firstly established in the transmission 79, the first brake B1 is brought into the engagement state, and thus the carrier CA is fixed (see solid line 1st). The rotation number of the output member 30 at this time is given by the point "A".

When the forward second shift stage is then established in the transmission 79, the first clutch C1 is brought into the engagement state so that the sun gear, the carrier, and the ring gear are rotated at the same rotation speed (see solid line 2nd). The rotation number of the output member 30 at this time is given by the point "B".

At the time of the backward movement of the vehicle 1, the electronic control unit 40 is operative to have the first brake B1 brought into the engagement state in a similar manner to the case of the forward first shift stage, and to have the output shaft of the motor generator 22 reversely rotated. The electronic control unit 40 may be operative to have the output shaft of the motor generator 22 reversely rotated under the established forward second shift stage at the time of the backward movement of the vehicle 1.

(Second Other Construction Example)
The second other construction example of the transmission according to the present invention will be explained hereinafter with reference to FIGS. 22 to 24.

As shown in FIG. 22, the transmission 81 has a double pinion type of planetary gear 38, a first clutch C1, and a first brake B1, which are accommodated in a transmission case not shown.

The input member 28 is connected with a ring gear R. The output member 30 is connected with a sun gear S, and selectively connected with or disconnected from a carrier CA through the first clutch C1. The first brake B1 is adapted to selectively fix or release the carrier CA.

FIG. 23 is an operation table of the transmission 81. For establishing the forward first shift stage, the electronic control unit 40 is operative to have the first clutch C1 brought into the engagement state. At this time, both the rotation speed of the output member 30 to the rotation speed of the input member 28, and the gear ratio come to be 1.

For establishing the forward second shift stage, the electronic control unit 40 is operative to have the first brake B1 brought into the engagement state. At this time, the rotation speed of the output member 30 to the rotation speed of the input member 28 is 1 /"lambda", and the gear ratio is "lambda".

The collinear graph view of the transmission 81 for executing the speed change as previously mentioned is shown in FIG. 24.

When the forward first shift stage is firstly established in the transmission 81, the first clutch C1 is brought into the engagement state so that the sun gear, the carrier, and the ring gear are rotated at the same rotation speed (see solid line 1st). The rotation number of the output member 30 at this time is given by the point "A".

When the forward second shift stage is then established in the transmission 81, the first brake B1 is brought into the engagement state, and thus the carrier CA is fixed (see solid line 2nd). The rotation number of the output member 30 at this time is given by the point "B".

At the time of the backward movement of the vehicle 1, the electronic control unit 40 is operative to have the first clutch C1 brought into the engagement state in a similar manner to the case of the forward first shift stage, and to have the output shaft of the motor generator 22 reversely rotated. The electronic control unit 40 may be operative to have the output shaft of the motor generator 22 reversely rotated under the established forward second shift stage at the time of the backward movement of the vehicle 1.

(Third Other Construction Example)
The third other construction example of the transmission according to the present invention will be explained hereinafter with reference to FIGS. 25 to 27.

As shown in FIG. 25, the transmission 83 has a single pinion type of planetary gear 41, a first clutch C1, and a first brake B1, which are accommodated in a transmission case not shown.

The input member 28 is connected with a sun gear S, and selectively connected with or disconnected from a carrier CA through the first clutch C1. The output member 30 is connected with the carrier CA. The first brake B1 is adapted to selectively fix or release the ring gear R.

FIG. 26 is an operation table of the transmission 83. For establishing the forward first shift stage, the electronic control unit 40 is operative to have the first brake B1 brought into the engagement state. At this time, the rotation speed of the output member 30 to the rotation speed of the input member 28 is "lambda"/(1 + "lambda"), while the gear ratio is (1 + "lambda")/"lambda".

The collinear graph view of the transmission 83 for executing the speed change as previously mentioned is shown in FIG. 27.

When the forward first shift stage is firstly established in the transmission 83, the first brake B1 is brought into the engagement state, and thus the ring gear R is fixed (see solid line 1st). The rotation number of the output member 30 at this time is given by the point "A".

When the forward second shift stage is then established in the transmission 83, the first clutch C1 is brought into the engagement state so that the sun gear, the carrier, and the ring gear are rotated at the same rotation speed (see solid line 2nd). The rotation number of the output member 30 at this time is given by the point "B".

(Fourth Other Construction Example)
The fourth other construction example of the transmission according to the present invention will be explained hereinafter with reference to FIGS. 28 to 30.

As shown in FIG. 28, the transmission 85 has a single pinion type of planetary gear 41, a first clutch C1, and a first brake B1, which are accommodated in a transmission case not shown.

The input member 28 is connected with a carrier CA. The output member 30 is connected with a ring gear R, and is selectively connected with or disconnected from the carrier CA through the first clutch C1. The first brake B1 is adapted to selectively fix or release the sun gear S.

FIG. 29 is an operation table of the transmission 85. For establishing the forward first shift stage, the electronic control unit 40 is operative to have the first clutch C1 brought into the engagement state. At this time, both the rotation speed of the output member 30 to the rotation speed of the input member 28, and the gear ratio come to 1.

For establishing the forward second shift stage, the electronic control unit 40 is operative to have the first brake B1 brought into the engagement state. At this time, the rotation speed of the output member 30 to the rotation speed of the input member 28 is 1 + "lambda", and the gear ratio is 1/(1 + "lambda").

The collinear graph view of the transmission 85 for executing the speed change as previously mentioned is shown in FIG. 30.

When the forward first shift stage is firstly established in the transmission 85, the first clutch C1 is brought into the engagement state so that the sun gear, the carrier, and the ring gear are rotated at the same rotation speed (see solid line 1st). The rotation number of the output member 30 at this time is given by the point "A".

When the forward second shift stage is then established in the transmission 85, the brake B1 is brought into the engagement state, and thus the sun gear S is fixed (see solid line 2nd). The rotation number of the output member 30 at this time is given by the point "B".

(Fifth Other Construction Example)
The fifth other construction example of the transmission according to the present invention will be explained hereinafter with reference to FIGS. 31 to 33.

As shown in FIG. 31, the transmission 87 has a single pinion type of planetary gear 41, a first clutch C1, and a first brake B1, which are accommodated in a transmission case not shown.

The input member 28 is connected with a carrier CA, and is selectively connected with or disconnected from a sun gear S through the first clutch C1. The output member 30 is connected with the sun gear S. The first brake B1 is adapted to selectively fix or release the ring gear R.

FIG. 32 is an operation table of the transmission 87. For establishing the forward first shift stage, the electronic control unit 40 is operative to have the first clutch C1 brought into the engagement state. At this time, both the rotation speed of the output member 30 to the rotation speed of the input member 28, and the gear ratio come to 1.

For establishing the forward second shift stage, the electronic control unit 40 is operative to have the first brake B1 brought into the engagement state. At this time, the rotation speed of the output member 30 to the rotation speed of the input member 28 is (1 + "lambda")/"lambda", and the gear ratio is "lambda"/(1 + "lambda").

The collinear graph view of the transmission 87 for executing the speed change as previously mentioned is shown in FIG. 33.

When the forward first shift stage is firstly established in the transmission 87, the first clutch C1 is brought into the engagement state so that the sun gear, the carrier, and the ring gear are rotated at the same rotation speed (see solid line 1st). The rotation number of the output member 30 at this time is given by the point "A".

When the forward second shift stage is then established in the transmission 87, the brake B1 is brought into the engagement state, and thus the ring gear R is fixed (see solid line 2nd). The rotation number of the output member 30 at this time is given by the point "B".

(Sixth Other Construction Example)
The sixth other construction example of the transmission according to the present invention will be explained hereinafter with reference to FIGS. 34 to 36.

As shown in FIG. 34, the transmission 89 has a single pinion type of planetary gear 41, a first clutch C1, and a first brake B1, which are accommodated in a transmission case not shown.

The input member 28 is connected with a ring gear R, and is selectively connected with or disconnected from a carrier CA through the first clutch C1. The output member 30 is connected with the carrier CA. The first brake B1 is adapted to selectively fix or release the sun gear S.

FIG. 35 is an operation table of the transmission 89. For establishing the forward first shift stage, the electronic control unit 40 is operative to have the first brake B1 brought into the engagement state. At this time, the rotation speed of the output member 30 to the rotation speed of the input member 28 is 1/(1 + "lambda"), and the gear ratio is 1 + "lambda".

The collinear graph view of the transmission 89 for executing the speed change as previously mentioned is shown in FIG. 36.

When the forward first shift stage is firstly established in the transmission 89, the first brake B1 is brought into the engagement state, and thus the sun gear S is fixed (see solid line 1st). The rotation number of the output member 30 at this time is given by the point "A".

When the forward second shift stage is then established in the transmission 89, the clutch C1 is brought into the engagement state so that the sun gear, the carrier, and the ring gear are rotated at the same rotation speed (see solid line 2nd). The rotation number of the output member 30 at this time is given by the point "B".

As has previously been described, the transmission according to the first to sixth other construction examples are each constructed by one planetary gear and two friction engagement devices, thereby making it possible to downsize the transmission and to reduce the loss of meshing gears and the drag loss.

As will be understood from the foregoing description, the transmission according to the present invention can accomplish an advantage effect to enhance the durability of the rotating electric machine even with the low loss, and is therefore useful for the vehicle having the rotating electric machine as a power source.
Explanation of Reference Numerals

1, 60, 67: vehicles
10: engine
22: motor generator
24: inverter
26: battery
28: input member
30: output member
32: differential gear
33L, 33R: drive shafts
34L, 34R: front wheels
35L, 35R: rear wheels
36: transmission
38: planetary gear
40: electronic control unit
41: planetary gear
42: CPU
44: RAM
46: ROM
48: input output interface
50: ignition switch
51: shift lever
52: shift position sensor
53: accelerator pedal
54: accelerator opening degree sensor
55: brake pedal
56: brake position sensor
58: vehicle speed sensor
62: engine
65: power splitting device
68: clutch
71: transmission

Claims

A transmission to be disposed between a rotating electric machine serving as a power source of a vehicle and a drive wheel to transmit the rotation of an output shaft of the rotating electric machine to the drive wheel while changing the speeds of the rotation of the output shaft of the rotating electric machine; comprising
a planetary gear device having an input member and an output member, and
a plurality of friction engagement devices for changing the power transmission states in the planetary gear device to establish forward three-shift stages in response to the engagement states of the friction engagement devices.
The transmission as set forth in claim 1, in which at least any one of the forward three-shift stages functions as a backward movement stage when the output rotation of the rotating electric machine is reversely rotated.
The transmission as set forth in claim 1 or 2, which further comprises an internal combustion engine serving as the power source, and in which the internal combustion engine and the rotating electric machine is mounted on the vehicle to be connected in series with each other through a power blocking device.
The transmission as set forth in claim 1 or 2, which further comprises an internal combustion engine serving as the power source, and a power splitting device connected with the output shaft of the internal combustion engine, the output shaft of the rotating electric machine, and the input member.
The transmission as set forth in any one of claims 1 to 4, in which
the planetary gear device is constituted by a double pinion type of planetary gear having a sun gear, a ring gear, and a carrier differentially rotatable with one another,
the output member being connected with the ring gear,
the plurality of friction engagement devices being constituted by a first friction engagement device adapted to selectively have the input member connected to or disconnected from the sun gear, a second friction engagement device adapted to selectively have the input member connected to or disconnected from the carrier, a third friction engagement device adapted to selectively fix or release the sun gear, and a fourth friction engagement device adapted to selectively fix or release the carrier.
The transmission as set forth in any one of claims 1 to 4, in which
the planetary gear device is constituted by a double pinion type of planetary gear having a sun gear, a ring gear, and a carrier differentially rotatable with one another,
the input member being connected with the ring gear,
the plurality of friction engagement devices being constituted by a first friction engagement device adapted to selectively have the carrier connected to or disconnected from the output member, a second friction engagement device adapted to selectively have the sun gear connected to or disconnected from the output member, a third friction engagement device adapted to selectively fix or release the carrier, and a fourth friction engagement device adapted to selectively fix or release the sun gear.
The transmission as set forth in any one of claims 1 to 4, in which
the planetary gear device is constituted by a single pinion type of planetary gear having a sun gear, a ring gear, and a carrier differentially rotatable with one another,
the plurality of friction engagement devices being constituted by a first friction engagement device adapted to selectively have the ring gear connected to or disconnected from the output member, a second friction engagement device adapted to selectively have the carrier connected to or disconnected from the output member, a third friction engagement device adapted to selectively have the input member connected to or disconnected from the carrier, and a fourth friction engagement device adapted to selectively have the input member connected to or disconnected from the sun gear, a fifth friction engagement device adapted to selectively fix or release the sun gear, and a sixth friction engagement device adapted to selectively fix or release the ring gear.
The transmission as set forth in any one of claims 1 to 4, in which
the planetary gear device is constituted by a single pinion type of planetary gear having a sun gear, a ring gear, and a carrier differentially rotatable with one another,
the plurality of friction engagement devices being constituted by a first friction engagement device adapted to selectively have the input member connected to or disconnected from the ring gear, a second friction engagement device adapted to selectively have the input member connected to or disconnected from the carrier, a third friction engagement device adapted to selectively have the carrier connected to or disconnected from the output member, and a fourth friction engagement device adapted to selectively have the sun gear connected to or disconnected from the output member, a fifth friction engagement device adapted to selectively fix or release the ring gear, and a sixth friction engagement device adapted to selectively fix or release the sun gear.
The transmission as set forth in any one of claims 1 to 4, in which
the planetary gear device is constituted by a single pinion type of planetary gear having a sun gear, a ring gear, and a carrier differentially rotatable with one another,
the plurality of friction engagement devices being constituted by a first friction engagement device adapted to selectively have the input member connected to or disconnected from the carrier, a second friction engagement device adapted to selectively have the input member connected to or disconnected from the sun gear, a third friction engagement device adapted to selectively have the carrier connected to or disconnected from the output member, and a fourth friction engagement device adapted to selectively have the sun gear connected to or disconnected from the output member, and a fifth friction engagement device adapted to selectively fix or release the ring gear.