POWER SPLIT TRANSMISSION

Abstract

A power split transmission which has a first part (2) and a second part (22) The first part (2) includes a variator (10), a summing gearset (6) and a shiftable transmission gear assembly (18). A standard transmission can be used as the multispeed transmission (23).

Claims

1-11. (canceled)

12. A power split transmission comprising: a first part (2), and a second part (22), the first part (2) comprising a continuous rotational speed variator (10) having a first unit (9) and a second unit (11), and a summing gearset (6) in a form of a planetary transmission, and the second part (22) comprising a multispeed transmission (23) by which a plurality of gear ratios are engagable such that in the first part (2) an input shaft (1), that is connectable to a drive motor, being functionally connectable on one side to the first unit (9) and, on the other side, to a first shaft (5) of the summing gearset (6), and the second unit (11) being functionally connectable with a second shaft (19) of the summing gearset (6), and the multispeed transmission (23) having an input shaft (21) which is either functionally connected to a third shaft (20) of the summing gearset (6) or is made integrally with the third shaft (20) of the summing gearset (6), and a shiftable transmission gear assembly (18), in which a first gear ratio and a second gear ratio are engagable, being arranged in functional connection either between the second unit (11) and the second shaft (19) of the summing gearset (6) or between the input shaft (1) of the first part (2) and the first shaft (5) of the summing gearset (6).

13. The power split transmission according to claim 12, wherein the variator (10) is in a form of either a hydraulic variator or an electrical variator.

14. The power split transmission according to claim 12, wherein the first gear ratio is designed such that when the input shaft (1) of the first part (2), which is connectable to the drive motor, is rotating, the variator (10) is adjustable in such manner that the input shaft (21) of the multispeed transmission (23) is not rotating, and the second gear ratio is designed such that when the input shaft (1) of the first part (2), which is connectable to the drive motor, is rotating, the input shaft (21) of the multispeed transmission (23) cannot be brought to rest.

15. The power split transmission according to claim 14, wherein the first gear ratio is engaged automatically below a predefined rotational speed of a drive output shaft (24) of the multispeed transmission (23).

16. The power split transmission according to claim 12, wherein while the second unit (11) is at rest the transmission gear assembly (18) is shifted.

17. The power split transmission according to claim 12, wherein while the second unit (11) is rotating, the transmission gear assembly (18) is shifted and, during the shift, a gear ratio in the variator (10) is changed.

18. The power split transmission according to claim 12, wherein the multispeed transmission (23) has at least two shiftable gear ratios, in a first rotational direction, and at least one shiftable gear ratio, in a second rotational direction.

19. The power split transmission according to claim 18, wherein gear ratios of respective ratio steps of the multispeed transmission (23) are coordinated with the variator (10) in such a manner that when a full variator adjustment range is used, a drive output rotational speed of respective adjacent driving ranges of the multispeed transmission (23) is reached or slightly overlapped.

20. The power split transmission according to claim 19, wherein when the multispeed transmission (23) is shifted, a gear ratio of the variator (10) is adapted.

21. The power split transmission according to claim 12, wherein a rotational direction of the input shaft (21) of the multispeed transmission (23) is unchangable by changing a gear ratio of the variator (10).

22. The power split transmission according to claim 18, wherein gear ratios of respective ratio steps of the multispeed transmission (23) are not reached and not overlapped, and a rotational speed and torque of the drive motor are adapted.

23. A power split transmission comprising: first and second parts; the first part having a summing planetary gearset and a continuous rotational speed variator comprising first and second units; the first part having an input shaft that is connectable to a drive engine, one side of the input shaft of the first part being functionally connected to the first unit of the variator, and another side of the input shaft of the first part being functionally connected to a first shaft of the summing planetary gearset; the second unit of the variator being functionally connectable to a second shaft (19) of the summing planetary gearset; the first part further having a shiftable transmission gear assembly in which first and second gear ratios are engagable and being arranged in functional connection either between the second unit and the second shaft of the summing gearset or between the input shaft and the first shaft of the summing gearset; the second part (22) that has a multispeed transmission (23) in which a plurality gear ratios are engagable, the multispeed transmission (23) having an input shaft (21) which is either functionally or integrally connected to a third shaft (20) of the summing planetary gearset (6) such that the input shaft of the second part rotates in unison with the third shaft of the summing planetary gearset.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Further characteristics emerge from the description of the figures, which show;

[0015] FIG. 1: A power split transmission with a first part and a second part;

[0016] FIG. 2: A power split transmission with a first part and a second part;

[0017] FIG. 3: A power split transmission with a first part and a second part;

[0018] FIG. 4: A power split transmission with a first part and a second part;

[0019] FIG. 5: A power split transmission with a first part and a second part; and

[0020] FIG. 6: A power split transmission with a first part and a second part.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] FIG. 1:

[0022] A drive motor, for example an internal combustion engine, drives the input shaft 1 of the first part 2 of the power split transmission. By way of a spur gear 3 and a spur gear 4, the input shaft 1 drives the shaft 5 of the summing gearset 6. Furthermore, by way of a spur gear 7 and a spur gear 8 the input shaft 1 drives the first unit 9 of the rotational speed variator 10. The second unit 11, which is functionally connected to the first unit 9, drives spur gears 12 and 13. The second unit 11 is preferably in the form of a hydraulic constant unit, for example a constant axial piston machine, and the first unit 9 is in the form of a hydraulic unit whose stroke volume can be adjusted. However, it is also possible for the first and second units 9 and 11 to be electrical units. The spur gear 12 is functionally connected to the spur gear 14 and the spur gear 13 is functionally connected to the spur gear 15. Together with the clutches 16 and 17 the spur gears 14 and 15 form the shiftable transmission gear assembly 18. Depending on whether the clutch 16 or 17 is closed, the shaft 19 of the summing gearset 6 is connected to the second unit 11 with a larger or smaller gear ratio. The shaft 20 is connected to the input shaft 21 of the second part 22 or made integrally therewith. In this way the rotational speed and the torque of the output of the summing gearset 6 are transmitted by way of the shaft 20 to the second part 22. Thus, depending on requirements, a standard multispeed transmission 23 can be used as the second part 22. The multispeed transmission 23 shown in FIG. 1 is in the form of a countershaft multispeed transmission wherein the drive output shaft 24, which for example can drive an axle-drive bevel gear of the rear axle of a tractor, is connected to the input shaft 21 by way of various shiftable gear ratios by means of the clutches 25, 26, 27, 28 and the shifting elements 29 and 30. By means of the shifting elements 29 and 30 the rotational direction of the drive output shaft 24 can be changed so that the vehicle can be driven forward or in reverse. The various gear ratios are engaged by means of the clutches 25, 26, 27 and 28.

[0023] FIG. 2:

[0024] The second part 22 corresponds to the second part 22 in FIG. 1. The first part 2 contains the shiftable transmission gear assembly 18 on the input shaft 1, and depending on the shifting position of the clutches 16 and 17, the input shaft 1 is connected to the shaft 5 of the summing gearset 6. The second unit 11 is connected to the shaft 19 by way of the spur gears 13 and 15.

[0025] FIG. 3:

[0026] The first part 2 in FIG. 3 corresponds to the first part 2 in FIG. 1. The second part 22 comprises the clutches 27 and 28 by means of which the rotational direction of the drive output shaft 24 is changed, whereby a forward driving direction and a reverse driving direction are enabled, and also the clutches 25 and 26 and shifting elements 29 and 30 by the shifting of which the various gears can be engaged. The clutches 25 and 26 are in this case powershift clutches.

[0027] FIG. 4:

[0028] The first part 2 in FIG. 4 corresponds to the first part 2 in FIG. 2. The second part 22 in FIG. 4 corresponds to the second part 22 in FIG. 3.

[0029] FIG. 5:

[0030] The first part 2 in FIG. 5 corresponds to the first part 2 in FIG. 1. The second part 22 has the shifting element 29 by means of which the rotational direction of the drive output shaft 24 is changed, so enabling a shift from forward to reverse driving. By means of the clutches 25 and 26 and the shifting elements 29 and 30, the various gears can be engaged.

[0031] FIG. 6:

[0032] The first part 2 in FIG. 6 corresponds to the first part 2 in FIG. 2. The second part 22 in FIG. 6 corresponds to the second part 22 in FIG. 5.

INDEXES

[0033] 1 Input shaft [0034] 2 First part [0035] 3 Spur gear [0036] 4 Spur gear [0037] 5 Shaft [0038] 6 Summing gearset [0039] 7 Spur gear [0040] 8 Spur gear [0041] 9 First unit [0042] 10 Rotational speed variator [0043] 11 Second unit [0044] 12 Spur gear [0045] 13 Spur gear [0046] 14 Spur gear [0047] 15 Spur gear [0048] 16 Clutch [0049] 17 Clutch [0050] 18 Shiftable transmission gear assembly [0051] 19 Shaft [0052] 20 Shaft [0053] 21 Input shaft [0054] 22 Second part [0055] 23 Multispeed transmission [0056] 24 Drive output shaft [0057] 25 Clutch [0058] 26 Clutch [0059] 27 Clutch [0060] 28 Clutch [0061] 29 Shifting element [0062] 30 Shifting element