Eight-speed powertrain of automatic transmission for vehicle

• US 20080108472A1
• Filed: 11/30/2006
• Published: 05/08/2008
• Est. Priority Date: 11/06/2006
• Status: Active Grant

• Current Assignee: Hyundai Motor Company (Hyundai Motor Group)
• Original Assignee: Hyundai Motor Company (Hyundai Motor Group)
• Inventors: Seo, Kang Soo
• Granted Patent: US 7,608,008 B2
• Time in Patent Office: Days
• US Class Current: 475/275
• CPC Class Codes: F16H 2200/0056 the gear ratios comprising seven forward speeds
• CPC Class Codes: F16H 2200/006 the gear ratios comprising eight forward speeds
• CPC Class Codes: F16H 2200/0086 the gear ratios comprising two reverse speeds
• CPC Class Codes: F16H 2200/2012 with four sets of orbital gears
• CPC Class Codes: F16H 2200/2048 with seven engaging means
• CPC Class Codes: F16H 2200/2051 with eight engaging means
• CPC Class Codes: F16H 3/66 composed of a number of gear trains without drive passing from one train to another

Abstract

A eight-speed powertrain of an automatic transmission for a vehicle combining four simple planetary gear set with a plurality of clutches and brakes to realize seventh forward speed or eighth forward speed and two reverse speeds can improve power delivery performance and reduce fuel consumption.

Claims

1. An eight-speed powertrain of an automatic transmission for a vehicle comprising:

a first shift portion comprising first and second planetary gear sets, an input path to which power directly is input from an input shaft, and an intermediate output path outputting the power by decelerating; and

a second shift portion comprising third and fourth planetary gear set, a first intermediate input path receiving the power through the intermediate output path of the first shift portion, a second intermediate input path which the power is variably input from the input shaft, and a final output path shifting and outputting the power input through the first and the second intermediate input path;

wherein

a plurality of frictional elements operational elements forming the first and the second shift portion disposed between the operational elements and between the operational elements and a transmission housing such that the operational elements operates selectively as an input element and a fixed element.

2. The powertrain of claim 1, wherein:

the first planetary gear set comprises a single pinion planetary gear set comprising a first sun gear, a first ring gear, and a first planet carrier,

the second planetary gear set comprises a single pinion planetary gear set comprising a second sun gear, a second ring gear, and a second planet carrier,

the third planetary gear set comprises a single pinion planetary gear set comprising a third sun gear, a third ring gear, and a third planet carrier, and

the fourth planetary gear set comprises a single pinion planetary gear set

comprising a fourth sun gear, a fourth ring gear, and a fourth planet carrier.

3. The powertrain of claim 2, wherein:

the first shift portion comprises four operational elements by which

the first ring gear and the second planet carrier are directly connect and

the sun gear of the first planetary gear set and the sun gear of the second planetary gear set are directly connect.

4. The powertrain of claim 3, wherein:

the four operational elements,

the first operational element comprising the first sun gear and the second sun gear;

the second operational element comprising the first planet carrier;

the third operational element comprising the first ring gear and the second planet carrier; and

the fourth operational element comprising the second ring gear.

5. The powertrain of claim 4, wherein:

the fourth operational element comprises the input path by being fixedly connected to the input shaft,

the third operational element comprises an intermediate output path, and

the first and the second operational elements operates selectively as a fixed element.

6. The powertrain of claim 2, wherein:

the second shift portion comprises four operational elements by which

the third ring gear and the fourth planet carrier are directly connect, and

the third sun gear and the fourth sun gear are variably connected.

7. The powertrain of claim 6, wherein:

the four operational element,

a fifth operational element comprises the fourth ring gear;

a sixth operational element comprises the third ring gear and the fourth planet carrier;

a seventh operational element comprises the third planet carrier; and

a eighth operational element comprises the third sun gear and the fourth sun gear.

8. The powertrain of claim 7, wherein:

the fifth operational element comprises the first intermediate input path directly connected to the intermediate output path of the first shift portion,

the sixth operational element comprises the second intermediate input path variably connected to the input shaft, and

the seventh operational element comprises the final output path.

9. The powertrain of claim 8, wherein:

the sixth operational element is operated as a fixed element by being variably connected to the transmission housing.

10. The powertrain of claim 7, wherein:

the third sun gear and the fourth sun gear of the eighth operational element,

are variably connected each together, and

are variably connected to the transmission housing such that all of the third sun gear and the fourth sun gear or one thereof operate as fixed element.

11. The powertrain of claim 10, wherein:

the third sun gear is variably connected to the transmission housing.

12. The powertrain of claim 8, wherein:

the fifth operational element is variably connected to the transmission housing to operate as a fixed element.

13. An eight-speed powertrain of an automatic transmission for a vehicle formed by combining a first shift portion comprising first and second planetary gear sets and a second shift portion comprising third and fourth planetary gear sets, wherein the first shift portion comprises:

a first and a second operational elements,

a third operational element outputting power to the second shift portion and always operating as an intermediate output path,

a fourth operational element receiving from an input shaft and always operating as an input element,

and wherein the second shift portion comprises;

a fifth operational element comprises a first intermediate input path directly receiving the power through the intermediate output path and selectively operates as a fixed element,

a sixth operational element comprises a second intermediate input path selectively receiving the power from the input shaft and selectively operates as a fixed element,

a seventh operational element operates as a output element, and

an eighth operational element selectively operates as a fixed element.

14. The eight-speed powertrain of claim 13, wherein:

the first planetary gear set which is a single pinion planetary gear set comprising a first sun gear, a first ring gear, and a first planet carrier,

the second planetary gear set which is a single pinion planetary gear set comprising a second sun gear, a second ring gear, and a second planet carrier,

the third planetary gear set which is a single pinion planetary gear set comprising a third sun gear, a third ring gear, and a third planet carrier, and

the fourth planetary gear set which is a single pinion planetary gear set comprising a fourth sun gear, a fourth ring gear, and a fourth planet carrier.

15. The eight-speed powertrain of claim 14, wherein:

the first, the second, the third, the fourth planetary gear sets are sequentially disposed from an front portion of the transmission.

16. The eight-speed powertrain of claim 14, wherein:

the first sun gear and the second sun gear are fixedly connected,

the first ring gear and the second planet carrier are fixedly connected,

the third ring gear and the fourth planet carrier are fixedly connected, and

the third sun gear and the fourth sun gear are variably connected.

17. The eight-speed powertrain of claim 14, wherein:

the first operational element is the first, the second sun gear,

the second operational element is the first planet carrier,

the third operational element is the first ring gear and the second planet carrier,

the fourth operational element is the second ring gear,

the fifth operational element is the fourth ring gear,

the sixth operational element is the third ring gear and the fourth planet carrier,

the seventh operational element is the third planet carrier, and

the eighth operational element is the third and the fourth sun gears.

18. The eight-speed powertrain of claim 13, wherein:

the first and the second operational elements are variably connected to the transmission housing through a brake,

the third operational element is fixedly connected to the fifth operational element,

the fourth operational element is directly connected to the input shaft,

the fifth operational element is variably connected to the transmission housing through the brake,

the sixth operational element is variably connected to the input shaft through a clutch and variably connected to the transmission housing through the brake, and

the eighth operational element is variably connected to the transmission housing through the brake.

19. The eight-speed powertrain of claim 18, wherein:

a first clutch variably connecting the input shaft and the sixth operational element is disposed between the first shift portion and the second shift portion,

a second clutch variably connecting the first operational element and the second operational element is disposed in front of the transmission,

a third clutch variably connecting the eighth operational element and the transmission housing is disposed in the rear portion of the transmission,

a first brake variably connecting the second operational element and transmission housing is disposed in front of the transmission,

a second brake variably connecting the eighth operational element and the transmission housing is disposed in the rear portion of the transmission,

a third brake variably connecting the first operational element and the transmission housing is disposed in front of the transmission, and

a fourth brake variably connecting the sixth operational element and the transmission housing is disposed in the rear portion of the transmission.