Transmission device with secondarily coupled power split

Abstract

A transmission device with secondarily coupled power splitting, having hydrostatic and mechanical branches which can be summed by a summing gear system provided in the area of a central transmission shaft. At least two transmission ratio ranges, in the forward and reverse driving directions, can be obtained such that within the transmission ratio ranges the transmission ratio can, in each case, be varied continuously by a hydrostatic variator in the area of the hydrostatic branch. On the transmission input side, the central transmission shaft can directly couple a drive engine and functionally connect to both an auxiliary drive output shaft and a hydrostatic shaft of the variator, in the form of countershafts, and also to hydraulic pumps in the area of the transmission input. In the area of the transmission output, the central transmission shaft is coupled to a further hydrostatic shaft in the form of a countershaft.

Claims

1. A transmission device (2) with secondarily coupled power splitting, the transmission device (2) comprising: a hydrostatic branch (4) and a mechanical branch (5) which are summed by a summing gear system (7) provided in an area of a central transmission shaft (6), and at least two transmission ratio ranges in forward and in reverse driving directions such that, within the at least two transmission ratio ranges, the transmission ratio, in each case, being continuously variable by a hydrostatic variator (3) in an area of the hydrostatic branch (4), the central transmission shaft (6), on a transmission input side, being directly coupled to a drive engine (58) and the transmission input side of the central transmission shaft (6) being functionally connected for rotationally driving both an auxiliary drive output shaft (45), in a form of a countershaft, and also hydraulic pumps (53 to 55) in an area of the transmission input side of the central transmission shaft (6), and are output side of the central transmission shaft (6) rotationally driving an input hydrostatic shaft (22) of the hydrostatic variator (3), in a form of another countershaft, an output hydrostatic shaft (23) of the hydrostatic variator (3), in a form of a further countershaft being coupled to the mechanical branch (5) for supplying a hydrostatic input thereto; and the transmission device (2) having a transmission output (40).

2. The transmission device according to claim 1, wherein the central transmission shaft (6) is, in the area of the transmission input, functionally connected, by way of an drive output fixed wheel (43), respectively with the auxiliary drive output shaft (45) and with input gearwheels (44, 47 to 49) connected, in a rotationally fixed manner, to respective drive input shafts (50 to 52) of the hydraulic pumps (53 to 55).

3. The transmission device according to claim 1, wherein the central transmission shaft (6) is connected to the input hydrostatic shaft (22), on a transmission output side, by way of a central shaft fixed wheel (19), and the central shaft fixed wheel (19) meshes with an intermediate wheel (20) that meshes with a first further hydrostatic shaft fixed wheel (21) of the input hydrostatic shaft (22).

4. The transmission device according to claim 1, wherein the output hydrostatic shaft (23) is connected, in an area facing toward the transmission input, by way of a second further hydrostatic shaft fixed wheel (24) to a summing shaft (25) of the summing gear system (7) in a form of a planetary gearset.

5. The transmission device according to claim 1, wherein the hydrostatic variator (3) comprises first and second hydrostatic units (3A, 3B), and the first hydrostatic unit (3A) is an adjustable swash-plate unit and the second hydrostatic unit (3B) is a constant oblique-axis unit that has smaller dimensions that the first hydrostatic unit (3A).

6. A transmission device (2) with secondarily coupled power splitting, the transmission device comprising: a hydrostatic branch (4) and a mechanical branch (5) which can be summed together by a summing gear system (7) provided in an area of a central transmission shaft (6), at least two forward drive transmission ratio ranges for driving in a forward direction and at least two reverse drive transmission ratio ranges for driving in a reverse direction so that, within each of the at least two forward drive transmission ratio ranges and the at least two reverse drive transmission ratio ranges, a transmission ratio being continuously variable by a hydrostatic variator (3) of the hydrostatic branch (4), the central transmission shaft (6) having a transmission input side that is directly connectable to a drive engine (58), and the central transmission shaft (6) being functionally connected for rotationally driving both an auxiliary drive output shaft (45), which is a first countershaft, and also a plurality of hydraulic pumps (53 to 55) in an area of a transmission input side, wherein the hydraulic pumps (53 to 55) are disposed around the central transmissions shaft (6), which can be brought into direct functional connection by way of a drive input flange (57) with the drive engine (58), and an output side of the central transmission shaft (6) rotationally driving an input hydrostatic shaft (22) of the hydrostatic variator (3), in a form of second countershaft, and an output hydrostatic shaft (23) of the hydrostatic variator (3), which is a third countershaft, being coupled to the mechanical branch (5) for supplying hydrostatic input thereto.

7. The transmission device according to claim 6, wherein the central transmission shaft (6) is, in the area of the transmission input, functionally connected, by way of an drive output fixed wheel (43), respectively with the auxiliary drive output shaft (45) and with input gearwheels (44, 47 to 49) connected, in a rotationally fixed manner, to respective drive input shafts (50 to 52) of the hydraulic pumps (53 to 55).

8. The transmission device according to claim 6, wherein the central transmission shaft (6) is connected to the input hydrostatic shaft (22), on a transmission output side, by way of a central shaft fixed wheel (19), and the central shaft fixed wheel (19) meshes with an intermediate wheel (20) that meshes with a first further hydrostatic shaft fixed wheel (21) of the input hydrostatic shaft (22).

9. The transmission device according to claim 6, wherein the output hydrostatic shaft (23) is connected, in an area facing toward the transmission input, by way of a second further hydrostatic shaft fixed wheel (24) to a summing shaft (25) of the summing gear system (7) in a form of a planetary gearset.

10. The transmission device according to claim 6, wherein the hydrostatic variator (3) comprises first and second hydrostatic units (3A, 3B), and the first hydrostatic unit (3A) is an adjustable swash-plate unit and the second hydrostatic unit (3B) is a constant oblique-axis unit that has smaller dimensions that the first hydrostatic unit (3A).

11. A transmission device (2) with secondarily coupled power splitting, the transmission device (2) comprising: a hydrostatic branch (4) and a mechanical branch (5) which are summed by a summing gear system (7) provided in an area of a central transmission shaft (6), and at least two transmission ratio ranges in forward and in reverse driving directions such that, within the at least two transmission ratio ranges, the transmission ratio, in each case, being continuously variable by a variator (3) in an area of the hydrostatic branch (4), the central transmission shaft (6), on a transmission input side, being directly coupled to a drive engine (58) and the transmission input side of the central transmission shaft (6) being functionally connected for rotationally driving both an auxiliary drive output shaft (45), in a form of a countershaft, and also hydraulic pumps (53 to 55) in an area of the transmission input side of the central transmission shaft (6), and an output side of the central transmission shaft (6) rotationally driving an input hydrostatic shaft (22) of the variator (3), in a form of another countershaft, wherein the central transmission shaft (6) is connected to the input hydrostatic shaft (22), on a transmission output side, by way of a central shaft fixed wheel (19), and the central shaft fixed wheel (19) meshing with an intermediate wheel (20) that meshes with a first further hydrostatic shaft fixed wheel (21) of the input hydrostatic shaft (22), an output hydrostatic shaft (23) of the variator (3), in a form of a further countershaft, being coupled to the mechanical branch (5) for supplying a hydrostatic input thereto; and the transmission device (2) having a transmission output (40).

12. The transmission device according to claim 11, wherein the central transmission shaft (6) is, in the area of the transmission input, functionally connected, by way of an drive output fixed wheel (43), respectively with the auxiliary drive output shaft (45) and with input gearwheels (44, 47 to 49) connected, in a rotationally fixed manner, to respective drive input shafts (50 to 52) of the hydraulic pumps (53 to 55).

13. The transmission device according to claim 11, wherein the output hydrostatic shaft (23) is connected, in an area facing toward the transmission input, by way of a second further hydrostatic shaft fixed wheel (24) to a summing shaft (25) of the summing gear system (7) in a form of a planetary gearset.

14. The transmission device according to claim 11, wherein the variator (3) comprises first and second hydrostatic units (3A, 3B), and the first hydrostatic unit (3A) is an adjustable awash-plate unit and the second hydrostatic unit (3B) is a constant oblique-axis unit that has smaller dimensions that the first hydrostatic unit (3A).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Further advantages and advantageous further developments of the invention emerge from the example embodiment whose principle is described with reference to the drawings, which show:

(2) FIG. 1: A schematic representation of a drive-train of an articulated utility vehicle, with a preferred embodiment of the transmission device according to the invention;

(3) FIG. 2: A simplified, three-dimensional partial view of the drive-train in FIG. 1; and

(4) FIG. 3: A view of the transmission device of FIG. 1, shown from a point of view marked III in FIG. 2.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(5) FIG. 1 shows a vehicle drive-train 1 with a transmission device 2 of a vehicle, preferably in the form of an articulated utility vehicle. A hydrostatic variator 3 is provided for the continuous variation of a transmission ratio of the transmission device 2. The transmission device 2 is designed with secondary power splitting and with a hydrostatic branch 4 containing the variator 3 and a mechanical branch 5, which can be summed by means of a summing gear system 7, which is provided in the area of a central transmission shaft 6 and designed as a planetary gearset. In the transmission device 2 in each case four transmission ratio ranges in the forward and reverse driving directions can be obtained, and in each case the transmission ratio within the ratio ranges can be varied continuously by means of the hydrostatic variator 3.

(6) The variator 3 comprises a hydrostatic unit 3A in the form of a variable-displacement pump with two delivery directions as a swash-plate unit, and also a further, reversible hydrostatic unit 38 in the form of a constant oblique-axis unit, which has smaller dimensions than the hydrostatic unit 3A, the hydrostatic units being used both as pumps and as motors.

(7) Next to the planetary gearset 7 on the central transmission shaft 6 is located a change-speed transmission which, in addition to the planetary gearset 7 comprises three further planetary gearsets 9 to 11, whose shafts can be coupled to one another by means of five frictional shifting elements 12 to 16 in the manner described in detail later, in order to obtain the four transmission ratio ranges, all the shafts being arranged coaxially on the central transmission shaft 6. On the transmission output side of the change-speed transmission 8 two further frictional shifting elements 17, 18 are provided, such that when the frictional shifting element 17 is closed the vehicle can be driven in the forward direction whereas when the frictional shifting element 18 is closed a vehicle made with the vehicle drive-train 1 and the transmission device 2 can be driven in reverse.

(8) Furthermore, by way of a fixed wheel 19, an intermediate wheel 20 and a fixed wheel 21 of a hydrostatic shaft 22 configured as a countershaft that mesh together, the central transmission shaft 6 is functionally connected to the variator 3 or first hydrostatic unit 3A. A further hydrostatic shaft 23 of the hydrostat 3 is also made with a fixed wheel 24, which meshes with a gearwheel 26 connected in a rotationally fixed manner to a shaft 25, formed as a sun gear, of the planetary gearset 7.

(9) The central transmission shaft 6 is coupled in a rotationally fixed manner to a shaft 27 of the planetary gearset 7 made as a ring gear, which, like the sun gear 25, meshes with planetary gearwheels 28 of the planetary gearset 7 which in turn are mounted to rotate on a planetary carrier 29. The planetary carrier 29 of the planetary gearset 7 is connected in a rotationally fixed manner to a shaft 30 of the planetary gearset 9 in the form of a ring gear, and by means of the frictional shifting element 14 can be connected rotationally fixed to a shaft 31 of the planetary gearset 11 which forms a planetary carrier.

(10) The ring gear 27 of the planetary gearset 7 is in turn connected in a rotationally fixed manner to a shaft 32 of the planetary gearset 9 in the form of a planetary carrier, on which planetary gearwheels 33 are mounted to rotate, these gearwheels 33 meshing with the ring gear 30 and with a shaft 34 of the planetary gearset 9 formed as its sun gear. The sun gear 34 of the planetary gearset 9 is connected in a rotationally fixed manner to a shaft 35 of the planetary gearset 10 also in the form of a sun gear, and can be brought by means of the frictional shifting element 13 into rotationally fixed functional connection with a shaft 36 of the planetary gearset 11 which is again in the form of a sun gear.

(11) A ring gear or rather shaft 37 of the planetary gearset 10 can be coupled by means of the frictional shifting element 12 to the sun gear 36 of the planetary gearset 11, and meshes with planetary gearwheels 59 mounted to rotate on a shaft 38 of the planetary gearset 10 in the form of a planetary carrier, the gearwheels 59 in turn being engaged with the sun gear 35. The planetary carrier 38 of the planetary gearset 10 is in turn connected in a rotationally fixed manner to the ring gear 30 of the planetary gearset 9 and therefore, again by virtue of the frictional shifting element 14, can be brought into functional connection with the planetary carrier 31 of the planetary gearset 11. A shaft 39 in the form of a ring gear of the planetary gearset 11 can be rotationally fixed by means of the frictional shifting element 16, which is designed as a brake. The planetary carrier 31 can be coupled by means of the frictional shifting elements 17 and 18 to a transmission output 40 which is functionally connected to a front axle 41 and a rear axle 42.

(12) On the transmission input side the central transmission shaft 6 has a further fixed wheel 43, which meshes with a fixed wheel 44 of an auxiliary drive output shaft 45 in the form of a countershaft. The auxiliary drive output shaft 45 can be coupled in the area of a further frictional shifting element 46 to a drive input shaft 47A, by means of which auxiliary drive outputs of the vehicle built with the vehicle drive-train 1 can be driven.

(13) In addition, further gearwheels 47, 48 and 49 also mesh with the fixed wheel 44, these gearwheels being connected in a rotationally fixed manner to drive input shafts 50 to 52 of hydraulic pumps 53 to 55. In the present case, the hydraulic pumps 53 to 55 are designed as load-sensing pumps and are provided as the hydraulic supply of the vehicle built with the vehicle drive-train 1. A further hydraulic pump 56 arranged on the hydrostatic shaft 23 is designed as an internal gear pump and constitutes a system pressure pump for supplying transmission oil to the transmission device 2.

(14) As shown in FIGS. 2 and 3 the hydraulic pumps 53 to 56 are arranged in a space-saving manner in the area of the transmission input of the transmission device 2, disposed around the central transmission shaft 6, which can be brought into direct functional connection by way of a drive input flange 57 with a drive engine 58, preferably a diesel internal combustion engine.

(15) To obtain a first transmission ratio range for forward driving or for reverse driving, the frictional shifting elements 12 and 16 must be in their closed operating conditions, while the other frictional shifting elements 13, 14 and 15 have to be open. If a corresponding shift starting from the first transmission ratio range to the second transmission ratio range is required, the frictional shifting element 12 must be opened and the frictional shifting element 13 closed, while the frictional shifting element 16 remains closed and the shifting elements 14 and 15 remain open.

(16) Starting from the second transmission ratio range, if a shift to the third transmission ratio range is required the frictional shifting element 16 must be opened and the frictional shifting element 14 closed, while for a shift from the third transmission ratio range to the fourth transmission ratio range the frictional shifting element 14 must be opened and the further shifting element 15, at the same time as the frictional shifting element 13 is closed, must be changed to its closed operating condition.

INDEXES

(17) 1 Vehicle drive-train

(18) 2 Transmission device

(19) 3 Variator

(20) 3A, 3B Hydrostatic unit

(21) 4 Hydrostatic branch

(22) 5 Mechanical branch

(23) 6 Central transmission shaft

(24) 7 Summing gear system, planetary gearset

(25) 8 Change-speed transmission

(26) 9 to 11 Planetary gearset

(27) 12 to 18 Frictional shifting element

(28) 17, 18 Frictional shifting element

(29) 19 Fixed wheel

(30) 20 Intermediate wheel

(31) 21 Fixed wheel

(32) 22, 23 Hydrostatic shaft

(33) 24 Fixed wheel

(34) 25 Shaft, sun gear of the planetary gearset 7

(35) 26 Gearwheel

(36) 27 Shaft, ring gear of the planetary gearset 7

(37) 28 Planetary gearwheels of the planetary gearset 7

(38) 29 Planetary carrier of the planetary gearset 7

(39) 30 Shaft, ring gear of the planetary gearset 9

(40) 31 Shaft, planetary carrier of the planetary gearset 11

(41) 32 Shaft, planetary carrier of the planetary gearset 9

(42) 33 Planetary gearwheels of the planetary gearset 9

(43) 34 Shaft, sun gear of the planetary gearset 9

(44) 35 Shaft, sun gear of the planetary gearset 10

(45) 36 Shaft, sun gear of the planetary gearset 11

(46) 37 Shaft, ring gear of the planetary gearset 10

(47) 38 Shaft, planetary carrier of the planetary gearset 10

(48) 39 Shaft, ring gear of the planetary gearset 11

(49) 40 Transmission output

(50) 41 Front axle

(51) 42 Rear axle

(52) 43 Fixed wheel of the central transmission shaft

(53) 44 Fixed wheel of the auxiliary drive output shaft

(54) 45 Auxiliary drive output shaft

(55) 46 Further frictional shifting element

(56) 47A Drive input shaft

(57) 47 to 49 Gearwheel

(58) 50 to 52 Drive input shaft

(59) 53 to 56 Hydraulic pump

(60) 57 Drive input flange

(61) 58 Drive engine

(62) 59 Planetary gearwheels of the planetary gearset 10