KR100867695B1 - A 7th-speed power train of an automatic transmission - Google Patents

Abstract

A characteristic feature of the present invention resides in that it comprises a first sun gear connected directly to an input shaft, a first planetary carrier gear-connected to the first sun gear and directly connected to the case, a second planetary carrier gear- A double pinion planetary gear set comprising a first planetary gear set and a first planetary gear set geared to a planetary carrier and a second planetary carrier; And a second sun gear coupled to the first sun gear and the input shaft via a first clutch and connected to the case via a first brake, and a second sun gear coupled to the input shaft via a second clutch, A third planetary carrier connected to the first ring gear via a third clutch, a fourth planetary carrier gear-coupled to the second sun gear and connected to the case via a second brake, and a fourth planetary carrier, And a third ring gear coupled to the fourth planetary carrier and connected directly to the output shaft, and a second ring gear connected to the second planetary gear set It is done.

Automatic transmission, forward 7 speed, planetary gear set, sun gear, clutch

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an automatic transmission,

1 is a schematic diagram showing a conventional 6-speed power train.

FIG. 2 is a table showing operating factors of a conventional 6-speed power train. FIG.

3 is a schematic diagram illustrating a 7-speed power train in accordance with the present invention;

4 is a table of operating elements for a 7-speed powertrain according to the present invention.

[Description of Reference Numerals]

1: Case 2: Input shaft

3: Output shaft B1: First brake

B2: second brake C1: first clutch

C2: second clutch C3: third clutch

C4: Fourth clutch DGP: Double pinion planetary gear set

PC1: first planetary carrier PC2: second planetary carrier

PC3: 3rd planetary carrier PC4: 4th planetary carrier

R1: first ring gear R2: second ring gear

R3: Third ring gear RPG Modified Ravigneaux planetary gear set

S1: first sun gear S2: second sun gear

The present invention relates to a 7-speed power train of an automatic transmission, and more particularly, to a 7-speed power train of an automatic transmission for a vehicle which can realize 7-speed forward speed and 1-speed reverse speed.

Generally, the vehicle is provided with an automatic transmission capable of automatically controlling the running speed of the vehicle, and the multi-speed shifting mechanism of the automatic transmission is composed of a combination of a plurality of planetary gear sets.

The powertrain in which the plurality of planetary gear sets are combined performs a function of shifting the rotational torque from the torque converter that converts and transmits the engine torque to a multi-stage transmission to the output side.

The powertrain of such an automatic transmission is advantageous in terms of power performance and fuel consumption rate as it has many gear stages, so that a power train capable of implementing more gear stages is required.

In addition, even if the same number of gear stages are implemented, durability, power transmission efficiency, and size and weight are largely changed according to the combination of the planetary gear set, so that the powertrain can be made more compact and compact while minimizing power loss. Efforts to develop are continuing.

In developing a powertrain using a planetary gear set, it is not necessary to develop any new gear set but to use a single pinion planetary gear set, a double pinion planetary gear set, or a single and double pinion planetary gear set The combination of the combined rabine-type planetary gear set and the accompanying clutches, brakes, and one-way clutches can be arranged in any position to achieve the desired speed change ratio and the corresponding speed ratio without any power loss, And research has been carried out with the aim of improving the quality of life.

Particularly, in the case of a manual transmission, there is an inconvenience that the driver frequently shifts when the speed change stage is excessively large. However, in the case of the automatic transmission, the transmission control unit automatically controls the operation of the power train according to the operation state, It is very important to develop a power train capable of implementing more shift stages.

In order to meet this trend, various studies have been conducted on the 4th and 5th speed powertrains, and recently, an automatic transmission powertrain capable of realizing 6th speed forward and 1 reverse speeds has been developed.

As shown in Fig. 1, three single pinion planetary gear sets SPG1, SPG2 and SPG3 are combined from the front to the rear, for example. The first sun gear S1 of the first single pinion planetary gear set SPG1 is connected to the transmission And the first planetary carrier PC1 is fixedly connected to the case 1 via the first brake B1 and fixedly connected to the third ring gear R3 of the third single pinion planetary gearset SPG3 An output gear (OUT) is mounted and operated as an output element.

Further, the first ring gear R1 of the first single pinion planetary gear set SPG1 is directly connected to the second planetary carrier PC2 of the second single-pinion planetary gear set SPG2.

The second sun gear S2 of the second single pinion planetary gear set SPG2 is directly connected to the input shaft 2 and the second ring gear R2 is connected to the third sun gear S2 of the third single- And is directly connected to the planetary carrier PC3.

The second ring gear R2 and the third planetary carrier PC3 are variably connected to the input shaft 2 through the second clutch C2 and are simultaneously connected to the transmission case 1 via the second brake B2. ).

The third sun gear S3 of the third single pinion planetary gear set SPG3 is variably connected to the input shaft 2 via the first clutch C1 and is connected to the input shaft 2 via the third brake B3, (1).

2, the first brake B1 and the second brake B2 operate in forward speed 1 and the first brake B1 and the third brake B3 operate in forward speed 2, The first brake B1 and the first clutch C1 are operated in the third speed forward and the first brake B1 and the second clutch C2 are operated in the fourth forward speed and the first and second clutches C1 The second clutch C2 and the third brake B3 operate in the sixth speed forward and the first clutch C1 and the second brake B2 operate in the reverse first speed, And the reverse 1-speed gear stage.

However, in the power train as described above, the first, second and third ring gears R1, R2 and R3 are connected to the second, third and first planetary carriers PC2, PC3 and PC1, So that the total length of the automatic transmission becomes long. This causes a problem that the weight of the transmission becomes large.

Further, the output gear 2 is connected to the first planetary carrier PC1 to increase the working torque thereof, which causes a deterioration in the durability of the planetary carrier.

In this conventional device, since the speed change stage is limited to six speeds, there is a limit in improving the power performance and the fuel consumption rate.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a double pinion planetary gear set and a modified Ravigneaux planetary gear set, Speed transmission of an automatic transmission capable of improving the shifting feeling during running of the vehicle and shortening the shifting time and minimizing the impact force when a skip shift occurs in which the speed of the vehicle is rapidly reduced.

In order to accomplish the above object, a characteristic configuration of the present invention will be described as follows.

A seventh speed power train of an automatic transmission according to the present invention includes a first sun gear connected directly to an input shaft, a first planetary carrier gear-connected to the first sun gear and directly connected to the case, A double pinion planetary gear set comprising a carrier, a first ring gear meshed with the first planetary carrier and a second planetary carrier; And a second sun gear coupled to the first sun gear and the input shaft via a first clutch and connected to the case via a first brake, and a second sun gear coupled to the input shaft via a second clutch, A third planetary carrier connected to the first ring gear via a third clutch, a fourth planetary carrier gear-coupled to the second sun gear and connected to the case via a second brake, and a fourth planetary carrier, And a third ring gear coupled to the fourth planetary carrier and connected directly to the output shaft, and a second ring gear connected to the second planetary gear set It is done.

The present invention having such characteristics will be described in detail as follows.

FIG. 3 is a schematic view showing a 7-speed power train according to the present invention, and FIG. 4 is a table showing operating elements of a 7-speed power train according to the present invention.

As referred to herein, the present invention consists largely of one double pinion planetary gear set (DPG) and one modified Ravigneaux planetary gear set (RPG).

The double pinion planetary gear set DPG is provided with a first sun gear S1 directly connected to the input shaft 2 and a first planetary carrier PC1 and a second planetary carrier PC2 Are gear-coupled.

The first planetary carrier PC1 is directly connected to the casing 1 and the first planetary carrier PC1 and the second planetary carrier PC2 are gear- .

The modified Ravigneaux planetary gear set RPG is provided with a second sun gear S2 whose second sun gear S2 is connected to the input shaft 2 through the first clutch C1, And is connected to the case 1 via the first connector B1.

The third planetary carrier PC3 is connected to the input shaft 2 through the second clutch C2 and the third planetary carrier PC3 is connected to the input shaft 2 via the second clutch C2. And is connected to the first ring gear R1 via the third clutch C3.

A fourth planetary carrier PC4 is gear-engaged to the second sun gear S2 and the fourth planetary carrier PC4 is connected to the case 1 via a second brake B2.

The second ring gear R2 is gear-engaged with the third planetary carrier PC3 and the fourth planetary carrier PC4 and the second ring gear R2 is meshed with the fourth planetary gear mechanism And is connected to the first ring gear R1.

On the other hand, a third ring gear R3 is gear-engaged with the fourth planetary carrier PC4, and the third ring gear R3 is directly connected to the output shaft 3. [

Hereinafter, the present invention will be described in detail.

As shown in Figs. 3 and 4, the rotational force of the power input through the input shaft 2

Any one of the two operation elements including 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 The speed of the forward 7-speed and the speed of the reverse 1-speed, and then output through the output shaft 3.

The fourth clutch C4 and the second brake B2 are actuated and when the output is made to the forward first speed, the fourth clutch C4 and the first brake B1 The third clutch C3 and the first brake B1 are operated when the output is to the forward second speed.

The third clutch C3 and the fourth clutch C4 are actuated when outputting to the forward third speed. When the output is outputted to fourth forward speed, the first clutch C1 and the third clutch C3 are engaged The first clutch C1 and the fourth clutch C4 are actuated when the output is forward 5 speed.

The first clutch C1 and the second clutch C2 are actuated when the forward clutch 6 is output and the second clutch C2 and the fourth clutch C4 are engaged when the forward clutch 7 is output. It works.

As described above, when shifting from the reverse first speed state to the first forward speed, or from the first forward speed to the forward speed 7, one of the two operating elements in each shifting period maintains the operating state and the other one The shifting interval is changed, so that the shifting time can be shortened and the transmission feeling transmitted to the driver can be improved.

Further, in the skip-shift operation in which the speed change section is changed in two sections due to the rapid deceleration during the running of the vehicle, one of the two operating elements is maintained in the operating state and the other is changed to change the speed change section, will be.

As described above, according to the present invention, when shifting from the reverse first speed range to the forward speed range 7, the shift is made to any one of the two operation elements, so that the shifting time is shortened and the shifting feeling is improved. Therefore, .

In addition, since one of the two operating elements is maintained in an operating state during a skip-shift operation due to rapid deceleration during running of the vehicle, the vibration generated in the automatic transmission is minimized to prevent a safety accident in advance have.

Claims (1)

A first planetary carrier PC1 gear-connected to the first sun gear S1 and connected directly to the case 1, and a second sun gear S1 connected to the first sun gear S1, A double pinion planetary gear set DPG consisting of a second planetary carrier PC2 that is gear-engaged and a first ring gear R1 that is gear-connected to the first planetary carrier PC1 and the second planetary carrier PC2; And A second sun gear S2 connected to the first sun gear S1 and the input shaft 2 via the first clutch C1 and connected to the case 1 via the first brake B1, A third planetary carrier PC3 which is gear-coupled to the sun gear S2 and connected to the input shaft 2 through the second clutch C2 and connected to the first ring gear R1 via the third clutch C3, A fourth planetary carrier PC4 which is gear-meshed with the second sun gear S2 and connected to the case 1 through a second brake B2 and a third planetary carrier PC4, A second ring gear R2 geared to the fourth planetary carrier PC4 and connected to the first ring gear R1 via a fourth clutch C4, And a third ring gear (R 3) connected directly to the first ring gear (R 3). The seventh-speed power train of the automatic transmission includes a modified Ravigneaux planetary gear set (RPG).

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