Multi-range hydro-mechanical transmission

• US 8,452,500 B1
• Filed: 02/28/2012
• Issued: 05/28/2013
• Est. Priority Date: 02/28/2012
• Status: Active Grant

• Current Assignee: Caterpillar Incorporated
• Original Assignee: Caterpillar Incorporated
• Inventors: Seipold, John M.
• Primary Examiner(s): Marc, McDieunel
• Application Number:
  US13/407,280
• Time in Patent Office: 455 Days
• Field of Search: 701/55, 475/75, 475/79, 475/81, 475/82, 475/83, 475/204, 475/218, 475/263, 475/279, 475/290, 475/330, 475/331, 475/332, 475/337, 475/343, 475/347, 744/10, 746/40
• US Class Current: 701/55
• CPC Class Codes: F16H 47/04 the mechanical gearing being of the type with members having orbital motion
• CPC Class Codes: F16H 61/462 for achieving a target speed ratio
• CPC Class Codes: Y10T 74/19 Gearing
• CPC Class Codes: Y10T 74/19628 Pressure distributing

Abstract

A powertrain includes an engine and a continuously variable transmission including a planetary gear arrangement and a variator. An input drives the variator and the planetary gears. A first planetary output gear is connected to the first output of the planetary gear arrangement. A second planetary output gear is connected to the first output, and a third planetary output gear is connectable by a first clutch to a second output of the planetary gear arrangement. A first output member is connected to the third planetary output gear, a second clutch releasably connects the first output member with the first planetary output gear, a third clutch connects the first output member with the second planetary output gear, a fourth clutch connects the second output member with the first planetary output gear, and a fifth clutch connects the second output member with the second planetary output gear.

Claims

1. A machine powertrain that includes an engine connected to a continuously variable transmission, the continuously variable transmission comprising:

a planetary gear arrangement having an input, and at least a first output and a second output;

a variator including a variable displacement hydraulic pump operably associated with a hydraulic motor, the hydraulic motor configured to drive a gear set of the planetary gear arrangement;

an input shaft driven by the engine and configured to drive the variator and the input of the planetary gear arrangement;

a first planetary output gear connected to the first output of the planetary gear arrangement;

a second planetary output gear connected to the second output of the planetary gear arrangement;

a third planetary output gear connectable via a first clutch to the second output of the planetary gear arrangement;

a first output member and a second output member of the transmission, the first output member being connected to the third planetary output gear, the first and second output members being interconnected with a transmission output;

a second clutch configured to releasably connect the first output member with the first planetary output gear;

a third clutch configured to releasably connect the first output member with the second planetary output gear;

a fourth clutch configured to releasably connect the second output member with the first planetary output gear; and

a fifth clutch configured to releasably connect the second output member with the second planetary output gear.

2. The machine of claim 1, wherein the first and second output members are configured to rotate in opposite directions.

3. The machine of claim 1, wherein the second and third clutches are integrated into a single compound clutch.

4. The machine of claim 1, wherein the fourth and fifth clutches are integrated into a single compound clutch.

5. The machine of claim 1, wherein the planetary gear arrangement includes first and second gear sets, each gear set having a sun gear, a carrier gear, and a ring gear, wherein the sun gears of the first and second gear sets are connected to the second output of the planetary gear arrangement, and wherein the ring gear of the first gear set and the carrier gear of the second gear set are connected to the first output of the planetary gear arrangement.

6. The machine of claim 5, wherein the input of the planetary gear arrangement is connected to the carrier gear of the first gear set, and wherein the variator is connected to the ring gear of the second gear set.

7. The machine of claim 1, wherein a first forward gear is engaged when the first clutch is engaged, a second forward gear is engaged when the second clutch is engaged, a third forward gear is engaged when the third clutch is engaged, a first reverse gear is engaged when the fourth clutch is engaged, and a second reverse gear is engaged when the fifth clutch is engaged.

8. The machine of claim 1, wherein a first set of drive gears interconnects the first planetary output gear with the second and fourth clutches, and wherein a second set of drive gears interconnects the second planetary output gear with the third and fifth clutches.

9. A continuously variable transmission, comprising:

a planetary gear arrangement having a first output and a second output, the planetary gear arrangement including first and second gear sets, each gear set having a sun gear, a carrier gear, and a ring gear, wherein the ring gear of the first gear set is connected to the carrier gear of the second gear set, the second output is connected to the sun gears of the first and second gear sets, and wherein the first output is connected to the ring gear of the first gear set and to the carrier gear of the second gear set;

a variator including a variable displacement hydraulic pump operably associated with a hydraulic motor, the hydraulic motor having an output connected to the ring gear of the second gear set;

an input shaft connected to the variable displacement hydraulic pump of the variator and to the carrier gear of the first gear set;

a first planetary output gear connected to the first output of the planetary gear arrangement;

a second planetary output gear connected to the second output of the planetary gear arrangement;

a third planetary output gear connectable via a first clutch to the second output of the planetary gear arrangement;

a first output member and a second output member of the transmission, the first output member being connected to the third planetary output gear, the first and second output members being interconnected with a transmission output;

a second clutch configured to releasably connect the first output member with the first planetary output gear;

a third clutch configured to releasably connect the first output member with the second planetary output gear;

a fourth clutch configured to releasably connect the second output member with the first planetary output gear; and

a fifth clutch configured to releasably connect the second output member with the second planetary output gear.

10. The continuously variable transmission of claim 9, wherein the first and second output members are configured to rotate in opposite directions.

11. The continuously variable transmission of claim 9, wherein the second and third clutches are integrated into a single compound clutch.

12. The continuously variable transmission of claim 9, wherein the third and fourth clutches are integrated into a single compound clutch.

13. The continuously variable transmission of claim 9, wherein a first forward gear is engaged when the first clutch is engaged, a second forward gear is engaged when the second clutch is engaged, a third forward gear is engaged when the third clutch is engaged, a first reverse gear is engaged when the fourth clutch is engaged, and a second reverse gear is engaged when the fifth clutch is engaged.

14. The continuously variable transmission of claim 9, wherein a respective one of three forward gears and two reverse gears is engaged when each of the first, second, third, fourth, and fifth clutches is engaged while the remaining clutches are disengaged.

15. The continuously variable transmission of claim 14, wherein a shift from a current gear selection to a new gear selection includes a disengagement of one clutch and the engagement of another clutch, the clutch and the another clutch selected from the group consisting of the first clutch, second clutch, third clutch, fourth clutch and fifth clutch.

16. The continuously variable transmission of claim 9, wherein a first set of drive gears interconnects the first planetary output gear with the second and fourth clutches, and wherein a second set of drive gears interconnects the second planetary output gear with the third and fifth clutches.

17. A method for operating a continuously variable transmission, comprising:

determining by a processor whether a shift from a current gear selection to a new gear selection is required;

analyzing by the processor parameters of the new gear selection;

comparing by the processor the parameters of the new gear selection to parameters of the current gear selection;

disengaging a current gear selection clutch and engaging a new gear selection clutch within a short time period;

modulating the disengaging and the engaging operations, and further modulating a variator contribution to ensure that a gear speed difference between the current gear selection and the new gear selection is substantially zero.

18. The method of claim 17, wherein the short time period is less than 250 milliseconds.

19. The method of claim 17, wherein the continuously variable transmission is configured for three forward-travel gear selections and two reverse-travel gear selections, wherein the continuously variable transmission includes five clutches, and wherein each of the five clutches corresponds to one of the three forward-travel and two reverse-travel gear selections.

20. The method of claim 17, wherein at least one of the analyzing, comparing, engaging, disengaging and modulating is accomplished in a transmission controlled configured to execute computer executable instructions stored in a tangible medium.