JPH05187489A - Automatic transmission for vehicle - Google Patents

Abstract

PURPOSE:To dispense with double changing over control as only two sets of planetary gear sets are used, and moreover the number of speed changing elements is lessened. CONSTITUTION:An input shaft IN is provided with the first planetary gear set PG1, and the second planetary gear set PG2 is provided so as to be coaxial to an output shaft OUT, and the first brake B1 to fix the first sun gear S1 to a case CA is provided. The second gear couple HG2 which can connect the first pinion carrier PC1 connected to the input shaft 1N with the second internal gear R2 through the second clutch C2 and the first gear couple HG1, and always connects the first internal gear R2 with the second sun gear S2 is provided. In addition, the first clutch C1 to mutually connect any two elements of the first planetary gear set PG1 is provided, and the third clutch C3 to mutually connect the second sun gear S2 and the second internal gear R2 is provided to always connect the second pinion carrier PC2 with the output shaft OUT.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic transmission which can be multi-staged with a small number of planetary gear sets.

[0002]

2. Description of the Related Art Conventionally, as automatic transmissions capable of obtaining a forward five speed, those disclosed in JP-A-63-303245 and JP-A-2-102951 are known. There is.

[0003]

However, in the former prior art, the forward 5th speed can be obtained with only two planetary gear sets, but there is double gear change, which actually causes a shift shock. It ’s difficult to shift so that it does n’t happen,
On the other hand, the latter conventional technique can eliminate double crossover, but it requires three planetary gear sets, which is disadvantageous in terms of cost and increases the total length of the gear train unit. is there.

The present invention has been made in view of the above problems, and it is advantageous in terms of cost to use only two sets of planetary gear sets and to reduce the number of transmission elements such as clutches and brakes. In addition, it is an object of the present invention to provide an automatic transmission for a vehicle in which the total length of the gear train unit can be shortened and the size can be reduced, and the double shift control need not be performed.

[0005]

Therefore, in order to achieve the above object, the vehicular automatic transmission of the present invention has an input shaft and an output shaft which are arranged in parallel, and the input shaft is provided with a first shaft. A single pinion-type first planetary gear set including the sun gear, the first pinion carrier, and the first internal gear is provided, and the second sun gear, the second pinion carrier, and the second internal are coaxial with the output shaft. Gear as an element,
A second pinion type second planetary gear set is provided, a first brake that can fix the first sun gear to a stationary portion is provided, and the first pinion carrier is connected to the input shaft and Provided so as to be connectable to the second internal gear via the two clutch and the first drive transmission mechanism,
The first internal gear and the second sun gear are always connected to each other, and a second drive transmission mechanism having a gear ratio different from that of the first drive transmission mechanism is provided, and any one of the three elements of the first planetary gear set is provided. A first clutch that connects the two elements is provided, a third clutch that connects the second sun gear and the second internal gear is provided, and the second pinion carrier is always connected to the output shaft. It was composed.

[0006]

In the first speed, the first brake and the second clutch are engaged. By this fastening, the first sun gear of the first planetary gear set is fixed to the stationary portion, and the first pinion carrier and the second internal gear are connected via the first drive transmission mechanism.

Therefore, in the first planetary gear set, torque is transmitted to the first internal gear by the speed increasing action. Then, torque is transmitted from the first internal gear to the second sun gear via the second drive transmission mechanism. Further, torque is transmitted from the first pinion carrier to the second internal gear via the second clutch and the first drive transmission mechanism. As a result, in the second planetary gear set, the second sun gear receives a torque that is accelerated by the first planetary gear set and further shifted based on the gear ratio (including the gear ratio 1) of the second drive transmission mechanism. On the other hand, when the torque changed based on the gear ratio (including the gear ratio 1) of the first drive transmission mechanism is input to the second internal gear, a decelerating action is obtained and the torque is coupled to the second pinion carrier. The decelerated state of the first speed can be obtained with the output shaft thus operated.

At the second speed, the first clutch and the second clutch are engaged. By this engagement, any two of the three elements of the first planetary gear set are connected, and the first pinion carrier and the second internal gear are connected.

Therefore, in the first planetary gear set, a torque transmission action with a gear ratio of 1 is obtained, and this torque is transmitted from the first internal gear to the second sun gear via the second drive transmission mechanism. In addition, in the second planetary gear set, torque is transmitted from the first pinion carrier to the second internal gear via the second clutch and the first drive transmission mechanism. Therefore, in this second planetary gear set, a deceleration action is obtained based on the difference in the gear ratios of the first and second drive transmission mechanisms,
With the pinion carrier and the output shaft, it is possible to obtain the second speed having a lower reduction ratio than the first speed.

In the third speed, the second clutch and the third clutch are engaged or the first clutch and the third clutch are engaged.

When the second clutch and the third clutch are engaged, this engagement connects the first pinion carrier and the second internal gear, and also connects the second sun gear and the second internal gear. To be done.

Therefore, the torque of the input shaft is input to the second internal gear via the second clutch and the first drive transmission mechanism, and is also input to the second sun gear in the connected state by the third clutch. As a result, in the second planetary gear set, torque is transmitted at the gear ratio of 1, so that an output based on the gear ratio of the first drive transmission mechanism is obtained at the output shaft. Therefore, the reduction ratio is lower than that of the second speed or the gear ratio is 1
Alternatively, it is possible to obtain a third speed or a fourth speed with a low speed increasing ratio.

On the other hand, when the first clutch and the third clutch are engaged, this engagement causes the first planetary gear set to
A torque transmission action with a gear ratio of 1 is performed, torque is transmitted from the first internal gear to the second sun gear via the second drive transmission mechanism, and the third sun gear is connected to the second sun gear by the third clutch. Torque is transmitted to the internal gear.

Therefore, in the second planetary gear set, the gear ratio is 1
The torque transmission action is obtained, and the output based on the gear ratio of the second drive transmission mechanism is obtained at the output shaft.

As described above, when the second clutch and the third clutch are engaged, an output based on the gear ratio of the first drive transmission mechanism is obtained, while the first clutch and the third clutch are engaged. In this case, an output based on the gear ratio of the second drive transmission mechanism is obtained. Therefore, based on the magnitude of the gear ratio of both drive transmission mechanisms, the one with the larger gear ratio is the third speed and the one with the smaller gear ratio is the fourth speed.

At the 5th speed, the third clutch and the first brake are engaged. Due to this fastening, in the first planetary gear set,
The first sun gear is fixed, while in the second planetary gear set,
The second sun gear and the second internal gear are connected.

Therefore, in the first planetary gear set, the speed increasing action is obtained, and the speed increasing torque is transmitted to the second sun gear through the second drive transmission mechanism, and the second sun gear is connected to the third clutch. It is transmitted to the connected second internal gear. As a result, in the second pinion carrier and the output shaft, the speed increasing ratio and the second
It is possible to obtain the fifth speed, which has a speed reduction ratio lower than the fourth speed or higher than the fourth speed based on the speed ratio of the drive transmission mechanism or higher than the first speed or the fourth speed.

[0018]

Embodiments of the present invention will be described below with reference to the drawings.

(First Embodiment) First, the structure will be described.

FIG. 1 is a skeleton diagram of an automatic transmission for a vehicle according to a first embodiment of the present invention.

An input shaft IN, which is arranged coaxially with an engine output shaft (not shown), and an output shaft OUT, which is arranged parallel to the input shaft IN and has a differential device (not shown), are provided. Also,
The third shaft SFT3 is provided coaxially with the output shaft OUT.

The input shaft IN is provided with a first sun gear.
S1, 1st pinion carrier PC1, 1st internal gear
Single pinion type first planetary gear set PG with R1 as an element
1 is provided, while the third shaft SFT3 includes a second sun gear S2, a second pinion carrier PC2, and a second internal gear R2 as elements, and a second pinion type second planetary gear set.
PG2 is provided.

The input shaft IN and the third shaft SFT3 are provided with a first gear pair (first drive transmission mechanism) HG1 and a second gear pair (second drive transmission mechanism) HG2, respectively. Torque can be transmitted from the IN side to the output shaft OUT side. That is, in the first gear pair HG1, one gear is provided so as to be connectable to the input shaft IN by the second clutch C2, and the other gear is always connected to the third shaft SFT3. Also, the second gear pair HG
2, one gear is always connected to the first internal gear R1 and the other gear is always connected to the second sun gear S2. The first gear pair HG1 is set to a gear ratio i less than 1, and the second gear pair HG2 is set to a gear ratio 1.

The first planetary gear set PG1 will be further described. The first sun gear S1 is provided with a first brake B1 capable of fixing the first sun gear S1 to the case CA. The first pinion carrier PC1 is always connected to the input shaft IN. The first sun gear S1 is connectable to the input shaft IN by the first clutch C1, that is, the first sun gear S1 and the first pinion carrier PC1 are connectable by the first clutch C1.

Next, the second planetary gear set PG2 will be described. The second pinion carrier PC2 is always connected to the output shaft OUT. The second internal gear R2 is the third shaft SF
It is always connected to T3 and can be connected to the second sun gear S2 by the third clutch C3. Also, the third
For the axis SFT3, the second axis SFT3 for fixing the third axis SFT3 to the case CA is used.
Brake B2 is provided.

Next, the operation will be described.

In the first embodiment, the clutches C1, C2, C3 as the shifting elements and the brakes B1, B2 are driven as shown in the shifting element operation diagram of FIG. 2 to shift gears. This operation will be described below for each gear stage.

[1st Speed] At 1st speed, as shown in FIG. 2, the first brake B1 and the second clutch C2 are engaged. By this fastening, the first sun gear S1 of the first planetary gear set PG1 is fixed to the case CA, and the first pinion carrier PC1
And the second internal gear R2 can transmit torque via the first gear pair HG1.

Therefore, as shown in FIG. 3 (I), the second
To the second internal gear of the planetary gear set PG2 R2 is the input shaft
IN-First gear pair HG1-Torque is transmitted through the path through the third shaft SFT3, while the second sun gear S2 of the second planetary gear set PG2 is transmitted.
Torque is transmitted to the input shaft IN, the first pinion carrier PC1, the first internal gear R1, and the second gear pair HG2. At this time, in the former torque transmission path, the speed is increased by the first planetary gear set PG1, while in the latter torque transmission path, the speed is reduced by the first gear pair HG1, and as a result, the second planetary gear set PG2 is decelerated. The action is obtained, and the output shaft OUT obtains the first speed with the reduction gear ratio as shown in the transmission element operation diagram of FIG. 2 and the alignment chart of FIG.

[Second speed] In the second speed, as shown in FIG. 2, the first clutch C1 and the second clutch C2 are engaged. By this engagement, the first sun gear S1 and the first pinion carrier
PC1 is connected, and the input shaft IN and the first gear pair HG1 are connected.

Therefore, as shown in FIG. 3 (II), the second
In the second sun gear S2 of the planetary gear set PG2, the input shaft IN-first
Torque is transmitted through the path via the sun gear S1 and the first pinion carrier PC1-first internal gear R1-second gear pair HG2, while the second internal gear R2 of the second planetary gear set PG2 has an input shaft IN-First gear pair HG1-Third axis SFT3
The torque is transmitted through the route. At this time, in the former torque transmission path, torque transmission with a gear ratio of 1 is performed, while in the latter torque transmission path, deceleration is performed by the first gear pair HG1, which causes the second planetary gear set PG2 to perform deceleration action. Thus, the output shaft OUT can obtain the second speed with the reduction ratio as shown in FIGS. 2 and 4.

[Third speed] In the third speed, as shown in FIG. 2, the second clutch C2 and the third clutch C3 are engaged. By this engagement, the input shaft IN and the first gear pair HG1 are connected, and the third shaft SFT3, the second internal gear R2, and the second sun gear S2 are connected.

Therefore, as shown in FIG. 3 (III), the second sun gear S2 and the second internal gear R2 of the second planetary gear set PG2 include the input shaft IN-the first gear pair HG1-the third shaft SF.
Torque is transmitted through the route via T3. At this time, since the second planetary gear set PG2 operates at the gear ratio 1, only the deceleration action of the first gear pair HG1 in the torque transmission path is obtained, and the output shaft OUT
Then, as shown in FIGS. 2 and 4, it is possible to obtain the third speed reduction ratio of the first gear pair HG1.

[In the 4th speed] In the 4th speed, as shown in FIG. 2, the first clutch C1 and the third clutch C3 are engaged.
By this fastening, the input shaft IN and the first pinion carrier
The PC1 and the first sun gear S1 are connected, and the second sun gear S2 and the second internal gear R2 are connected.

Therefore, as shown in FIG. 3 (IV), the input shaft IN-the first sun gear S1 and the first pinion carrier PC1
-The first internal gear R1-the second gear pair HG2-The second sun gear S2 and the second internal gear R2-The torque is transmitted to the output shaft OUT via the second pinion carrier PC2. At this time, the first planetary gear set PG1, the second planetary gear set HG2, and the second planetary gear set PG2 all perform a torque transmission action with a gear ratio of 1, and as a result, at the output shaft OUT, as shown in FIG. As shown in FIG. 4, it is possible to obtain the fourth speed with the gear ratio of 1.

[Fifth speed] In the fifth speed, as shown in FIG. 2, the third clutch C3 and the first brake B1 are engaged. As a result of this engagement, the first sun gear PG1
S1 is fixed to the case CA, while in the second planetary gear set PG2, the second sun gear S2 and the second internal gear R2 are connected.

Therefore, as shown in FIG. 3 (V), the input shaft IN-first pinion carrier PC1-first internal gear R1-second gear pair HG2-second sun gear S2 and second internal gear R2- Torque is transmitted to the output shaft OUT via the path via the second pinion carrier PC2. At this time, the first planetary gear set PG1 can obtain the speed increasing action, and the output shaft OUT can obtain the fifth speed having the reduction ratio as shown in FIGS.

[Reverse] During reverse, the first clutch C1 and the second brake B2 are engaged as shown in FIG. By this fastening, the input shaft IN and the first pinion carrier PC
1 and the first sun gear S1 are connected, and the second internal gear R2 of the second planetary gear set PG2 is fixed to the case CA.

Therefore, as shown in FIG. 3 (R), the input shaft IN-the first sun gear S1 and the first pinion carrier PC1
-First internal gear R1-Second gear pair HG2-Second sun gear S2-Second pinion carrier PC2 Torque is transmitted to the output shaft OUT by a route. At this time, the first planetary gear set PG
In the case of 1, the torque transmission action with the gear ratio of 1 is performed, while in the double pinion type second planetary gear set PG2, the second pinion carrier PC2 reverses while obtaining the deceleration action, and the output shaft OU
At T, as shown in FIGS. 2 and 4, a reverse speed with a high reduction ratio is obtained.

As described above, in the vehicle automatic transmission according to the embodiment, the forward 5th speed and the reverse 1st speed are obtained without changing control even though the planetary gear set is only two sets, PG1 and PG2. It is possible, and as a shifting element, 3
Since only a total of five elements, one clutch C1, C2, C3 and two brakes B1, B2, are used, it is advantageous in terms of cost and the axial dimension of the gear train unit can be shortened. It is practical.

(Second Embodiment) The configuration will be described.

FIG. 5 is a skeleton diagram of the vehicle automatic transmission according to the second embodiment of the present invention.

Since the automatic transmission of the second embodiment has basically the same configuration as that of the first embodiment, the same reference numerals as those of the first embodiment are given to the same configurations, and only the differences will be described. To do.

The input shaft IN is connected to the first pinion carrier PC1.
A fourth clutch C4 is provided so that it can be connected to the case, and the case
A second brake B2 is provided so that it can be fixed to CA.

Also, the input shaft IN and the second internal gear R2
The first gear pair HG1 is provided between the second sun gear S2 and the second sun gear S2, and the gear ratio of the first gear pair HG1 is set to 1.

The second clutch C2 is provided between the first gear pair HG1, the second internal gear R2 and the second sun gear S2.

The second gear pair HG2 is set to a gear ratio larger than 1.

Next, the operation will be described.

In the device of the second embodiment, the clutches C1, C2, C3, C4 and the brakes B1, B2 as the shifting elements are shown in FIG.
The gear shift operation is performed as shown in the gear shift element operation diagram of FIG.
This operation will be described below for each gear stage.

[1st speed] At 1st speed, as shown in FIG. 6, the first brake B1, the second clutch C2, and the fourth clutch C4.
Conclude By this engagement, the first sun gear S1 of the first planetary gear set PG1 is fixed to the case CA, the first pinion carrier PC1 is driven, and the first internal gear R1 is accelerated. Then, torque is transmitted from the first internal gear R1 to the second internal gear R2 via the second gear pair HG2. On the other hand, torque is also transmitted to the second sun gear S2 via the first gear pair HG1.

Therefore, as shown in FIG. 7 (I), the second
To the second internal gear of the planetary gear set PG2 R2 is the input shaft
IN-The torque is transmitted through the path through the first gear pair HG1, while the input sun shaft is connected to the second sun gear S2 of the second planetary gear set PG2.
IN-First pinion carrier PC1-First internal gear
Torque is transmitted in a route through R1-second gear pair HG2-third shaft SFT3. At this time, in the former torque transmission path, torque transmission with a gear ratio of 1 is performed, while in the latter torque transmission path, the speedup action is obtained by the first planetary gear set PG1, resulting in the second planetary gear set PG2. A deceleration action is obtained with the output shaft OU
At T, 1st speed will be obtained.

[Second speed] In the second speed, as shown in FIG. 6, the first clutch C1, the second clutch C2, and the fourth clutch C4.
Conclude By this engagement, the first sun gear S1 and the first pinion carrier PC1 are connected, and the first gear pair HG
1 and the second internal gear R2 are connected.

Therefore, as shown in FIG. 7 (II), the second
Input shaft IN-first sun gear S1 and first sun gear S1
Pinion carrier PC1-First internal gear R1-Second
Torque is transmitted through a path via the gear pair HG2-third shaft SFT3, while torque is transmitted to the second internal gear R2 through a path via the input shaft IN-first gear pair HG1. At this time, in the former torque transmission path, the speed is increased by the second gear pair HG2, while in the latter torque transmission path, the torque with the gear ratio of 1 is transmitted, which causes the deceleration action in the second planetary gear set PG2. It is possible to obtain 2nd speed with the output shaft OUT.

[Third speed] In the third speed, as shown in FIG. 6, the second clutch C2, the third clutch C3, and the fourth clutch C4.
And conclude. By this fastening, the first gear pair HG1 and the second gear pair
The second internal gear R2 and the second sun gear S2 are connected together with the internal gear R2 being connected.

Therefore, as shown in FIG. 7 (III), the second sun gear S2 and the second internal gear R2 of the second planetary gear set PG2 are connected via the input shaft IN-the first gear pair HG1. Torque is transmitted. At this time, since the second planetary gear set PG2 operates at the gear ratio 1, the output shaft OUT can obtain the third gear ratio of the gear ratio 1.

[In the 4th speed] In the 4th speed, as shown in FIG. 6, the first clutch C1, the third clutch C3, and the fourth clutch C4.
And conclude. By this engagement, the input shaft IN is connected to the first pinion carrier PC1 and the first sun gear S1, and the second sun gear S2 is connected to the second internal gear R2.

Therefore, as shown in FIG. 7 (IV), the second
The second sun gear S2 and the second internal gear R2 of the planetary gear set PG2 include the input shaft IN-the first sun gear S1 and the first pinion carrier PC1-the first internal gear R1-the second gear pair.
HG2-The second sun gear S2-The torque is transmitted through the route through the third shaft SFT3, the speed is increased based on the gear ratio of the second gear to HG2 on the way, and the increased fourth speed is obtained at the output shaft OUT. be able to.

[Fifth speed] In the fifth speed, as shown in FIG. 2, the third clutch C3, the fourth clutch C4, and the first brake B1
And conclude. By this engagement, the first planetary gear set PG1
Then, the first sun gear S1 is fixed to the case CA, and the first pinion carrier PC2 is connected to the input shaft IN.
In the second planetary gear set PG2, the second sun gear S2 and the second internal gear R2 are connected.

Therefore, as shown in FIG. 7 (V), input shaft IN-first pinion carrier PC1-first internal gear R1-second gear pair HG2-second sun gear S2 and second internal gear R2- Torque is transmitted to the output shaft OUT via the path through the second pinion carrier 2. At this time, the first planetary gear set PG1 and the second gear pair HG2 can increase the speed, and the output shaft OUT can obtain the fifth speed.

[Reverse] At the time of reverse, as shown in FIG. 6, the first clutch C1, the third clutch C3, and the second brake B2.
Conclude By this engagement, the input shaft IN, the first pinion carrier PC1 and the first sun gear S1 are connected, and the second internal gear R2 of the second planetary gear set PG2 is fixed to the case CA.

Therefore, as shown in FIG. 7 (R), the input shaft IN-the first sun gear S1-the first internal gear R1-the second
Gear pair HG2-third axis SFT-second sun gear S2 and second
The torque is transmitted to the output shaft OUT through a path that passes through the internal gear R2-the second pinion carrier PC2. At this time, the first
The planetary gear set PG1 has a reverse action, and the output shaft OUT has a reverse speed.

The embodiment has been described above with reference to the drawings. However, the specific configuration is not limited to this embodiment, and the present invention can be applied even if there is a design change or the like without departing from the scope of the invention. include.

For example, in the embodiment, a gear pair consisting of two gears is used as the first and second drive transmission mechanisms, but any means capable of transmitting torque at a constant gear ratio may be used, such as a chain or other means. May be used.

[0064]

As described above, in the vehicular automatic transmission of the present invention, the single pinion type first planetary gear set and the double pinion type are provided for the input shaft and the output shaft which are arranged in parallel, respectively. Second planetary gear set, a first brake capable of fixing the first sun gear to a stationary portion, a first pinion carrier always connected to the input shaft, a second clutch and a first drive transmission mechanism. A second drive transmission mechanism for connecting the first internal gear and the second sun gear at all times, the second drive transmission mechanism being provided so as to be connectable to the second internal gear via any one of the three elements of the first planetary gear set. A first clutch that connects the two elements is provided, and a second sun gear and a second clutch are provided.
Since the third clutch that connects the internal gear is provided, the second pinion carrier is always connected to the output shaft, and the second brake that can fix the second internal gear to the stationary portion is provided, 5 sets of forward speed with 2 sets of planetary gears
It is possible to obtain the first reverse speed, which is advantageous in terms of cost, and the overall length of the gear train unit can be shortened to achieve compactness, but it is possible to eliminate the need for double-shift control. can get.

[Brief description of drawings]

FIG. 1 is a skeleton diagram showing an automatic transmission for a vehicle according to a first embodiment of the present invention.

FIG. 2 is an operation diagram of a speed change element according to the first embodiment.

FIG. 3 is an operation explanatory view showing a torque transmission path of the first embodiment, in which (I) is at 1st speed, (II) is at 2nd speed, (III) is at 3rd speed, and (IV) is at 4th speed. At speed, (V) is at 5th speed, and (R) is at reverse.

FIG. 4 is a nomographic chart of the first embodiment.

FIG. 5 is a skeleton diagram showing an automatic transmission for a vehicle according to a second embodiment of the present invention.

FIG. 6 is a shift element operation diagram of the second embodiment.

FIG. 7 is an operation explanatory view showing a torque transmission path of the second embodiment, in which (I) is at 1st speed, (II) is at 2nd speed, (III) is at 3rd speed, and (IV) is at 4th speed. At speed, (V) is at 5th speed, and (R) is at reverse.

[Explanation of symbols]

 IN Input shaft OUT Output shaft PG1 1st planetary gear set S1 1st sun gear PC1 1st pinion carrier R1 1st internal gear PG2 2nd planetary gear set S2 2nd sun gear PC2 2nd pinion carrier R2 2nd internal gear C1 1st 1st clutch C2 2nd clutch C3 3rd clutch B1 1st brake B2 2nd brake HG1 1st gear pair (1st drive transmission mechanism) HG2 2nd gear pair (2nd drive transmission mechanism)

Claims (2)

[Claims] 1. An input shaft and an output shaft arranged in parallel, wherein the input shaft has a first sun gear, a first pinion carrier, and
A single pinion type first planetary gear set including a first internal gear as an element is provided, and a second sun gear, a second pinion carrier, and a second internal gear are included as elements, sometimes coaxially with the output shaft. A second pinion type second planetary gear set is provided, a first brake that can fix the first sun gear to a stationary portion is provided, and the first pinion carrier is connected to the input shaft and It is provided to be connectable to a second internal gear via a two-clutch and a first drive transmission mechanism, always connects the first internal gear and a second sun gear, and is a gear shift different from that of the first drive transmission mechanism. A second ratio drive transmission mechanism is provided, a first clutch is provided to connect any two of the three elements of the first planetary gear set, and the second sun gear and the second inner gear are provided. Third clutch is provided for coupling the gear and the second pinion carrier is always an automatic transmission for a vehicle, characterized in that it is connected to the output shaft. 2. The automatic gear shift system for a vehicle according to claim 1, wherein the first drive transmission mechanism and the second drive transmission mechanism are constituted by a mechanism for transmitting drive through a gear pair or a chain. Machine.