Power-split continuously variable transmission device

Abstract

A variator unit of a power-split continuously variable transmission is fixed to a rotationally fixed component and has a primary side rotationally fixed to an input shaft and a secondary side rotationally fixed to a first element of a second planetary gear set via a third shaft. A third element of a first planetary gear set is rotationally fixed via a fourth shaft to a second element of the second planetary gear set, which is fixable to the rotationally fixed component via a first shift element and connectable to the input shaft via a second shift element. A third element of the second planetary gear set is rotationally fixed via a fifth shaft to a first element of the first planetary gear set fixable to the rotationally fixed component via a third shift element. The second element of the first planetary gear set is rotationally fixed to an output shaft.

Claims

1. A power-split continuously variable transmission device (100), comprising: an input shaft (1); an output shaft (2); a first planetary gear set (RS1) arranged between the input shaft (1) and the output shaft (2); a second planetary gear set (RS2) connected to the first planetary gear set (RS1) and arranged between the input shaft (1) and the output shaft (2); and a variator unit (10) for transmitting power in a continuously variable manner from the input shaft (1) to the first planetary gear set (RS1), the variator unit (10) having a first shift element (B1), a second shift element (K1) and a third shift element (B2), selective actuation of the first, second and third shift elements (B1, K1, B2) implements different power paths via the variator unit (10) and the first and second planetary gear sets (RS1, RS2) while making a first mode (V1), a second mode (V2), and a third mode (R1) available, wherein the variator unit (10) is fixed to a rotationally fixed component (GG), a primary side (11) of the variator unit (10) is rotationally fixed to the input shaft (1), and a secondary side (12) of the variator unit is rotationally fixed to a first element (E21) of the second planetary gear set (RS2) via a third shaft (3), wherein a third element (E13) of the first planetary gear set (RS1) is rotationally fixed to a second element (E22) of the second planetary gear set (RS2) via a fourth shaft (4), the second element (E22) of the second planetary gear set (RS2) fixable to the rotationally fixed component (GG) via the first shift element (B1) and connectable to the input shaft (1) via the second shift element (K1), wherein a third element (E23) of the second planetary gear set (RS2) is rotationally fixed to a first element (E11) of the first planetary gear set (RS1) via a fifth shaft (5), the first element (E11) of the first planetary gear set (RS1) fixable to the rotationally fixed component (GG) via the third shift element (B2), and wherein the second element (E12) of the first planetary gear set (RS1) is rotationally fixed to the output shaft (2).

2. The transmission device (100) of claim 1, wherein the variator unit (10) is a planetary roller variator.

3. The transmission device (100) of claim 1, wherein the first and second planetary gear sets (RS1, RS2) are arranged axially adjacent to each other.

4. The transmission device (100) of claim 1, wherein the first planetary gear set (RS1) is arranged radially outside the second planetary gear set (RS2).

5. The transmission device (100) of claim 1, wherein: each of the first and second planetary gear sets (RS1, RS2) is a minus planetary gear set; the first element (E11) of the first planetary gear set (RS1) is a sun gear (SO1); the second element (E12) of the first planetary gear set (RS1) is a planet carrier (PT1); the third element (E13) of the first planetary gear set (RS1) is a ring gear (HO1); the first element (E21) of the second planetary gear set (RS2) is a sun gear (SO2); the second element (E22) of the second planetary gear set (RS2) is a planet carrier (PT2); and the third element (E23) of the second planetary gear set (RS2) is a ring gear (HO2).

6. The transmission device (100) of claim 1, wherein: the first planetary gear set (RS1) is a minus planetary gear set and the second planetary gear set (RS2) is a plus planetary gear set; the first element (E11) of the first planetary gear set (RS1) is a sun gear (SO1); the second element (E12) of the first planetary gear set (RS1) is a planet carrier (PT1); the third element (E13) of the first planetary gear set (RS1) is a ring gear (HO1); the first element (E21) of the second planetary gear set (RS2) is a sun gear (SO2); the second element (E22) of the second planetary gear set (RS2) is a ring gear (HO2); and the third element (E23) of the second planetary gear set (RS2) is a planet carrier (PT2).

7. The transmission device (100) of claim 1, wherein: the first mode (V1) is variable and implemented when the third shift element (B2) is engaged, and/or the second mode (V2) is power-split and implemented when the second shift element (K1) is engaged, and/or the third mode (R1) is variable and implemented when the first shift element (B1) is engaged.

8. The transmission device (100) of claim 1, further comprising an electric machine (EM), a rotor (R) of the electric machine (EM) is connected to the input shaft (1), the third shaft (3), the fourth shaft (4), the fifth shaft (5), one of the first, second, or third elements (E11, E12, E13, E21, E22, E23) of the first and second planetary gear sets (RS1, RS2) or to the output shaft (2).

9. The transmission device (100) of claim 8, further comprising a separating clutch, the input shaft (1) rotationally fixable to a connecting shaft via the separating clutch.

10. The transmission device (100) of claim 8, wherein the electric machine (EM) is arranged coaxially to the input shaft (1).

11. The transmission device (100) of claim 8, wherein the electric machine (EM) is arranged axially parallel to the input shaft (1).

12. A motor vehicle drive train comprising the transmission device (100) of claim 1.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention is explained in greater detail with reference to the following figures. In the figures, the following is shown:

(2) FIG. 1 shows a schematic view of a transmission device according to the invention in a preferred first embodiment;

(3) FIG. 2 shows a shift pattern of the transmission device according to FIG. 1;

(4) FIG. 3 shows a schematic view of a transmission device according to the invention in a preferred second embodiment;

(5) FIG. 4 shows a shift pattern of the transmission device according to FIG. 3;

(6) FIG. 5 shows a schematic view of a transmission device according to the invention in a preferred third embodiment;

(7) FIG. 6 shows a schematic view of a transmission device according to the invention in a preferred fourth embodiment;

(8) FIG. 7 shows a schematic view of a transmission device according to the invention in a preferred fifth embodiment; and

(9) FIG. 8 shows a schematic view of a transmission device according to the invention in a preferred sixth embodiment.

DETAILED DESCRIPTION

(10) Reference will now be made to embodiments of the invention, one or more examples of which are shown in the drawings. Each embodiment is provided by way of explanation of the invention, and not as a limitation of the invention. For example, features illustrated or described as part of one embodiment can be combined with another embodiment to yield still another embodiment. It is intended that the present invention include these and other modifications and variations to the embodiments described herein.

(11) FIG. 1 shows a schematic of a power-split continuously variable transmission device 100 in the form of a mechanical IVT transmission which, in the area of an input shaft 1, is operatively connected directly, i.e., without a coupling device, to a drive machine (not represented). The drive machine is an internal combustion engine in the form of a diesel engine or a gas engine.

(12) A torque which is made available by the drive machine and is present in the area of the input shaft 1 is guidable along multiple power paths, wherein a variator 10 is provided for varying a ratio of the respective power path, whereby the overall gear ratio of the transmission device 100 is continuously variable to the desired extent via the variator 10.

(13) The shares of the torque present on the transmission input side in the area of the input shaft 1, which are guided along the power paths, are guided in the direction of the output shaft 6.

(14) The transmission 100 further includes a first shift element B1, a second shift element K1, a third shift element B2 and one first planetary gear set RS1 connected to the variator 10. The transmission 100 also includes a second planetary gear set RS2 which is connected to the first planetary gear set RS1. Each of the first and third shift elements B1, B2 is a brake, and the second shift element K1 is a clutch. The first and second planetary gear sets are preferably simple (minus) planetary gear sets.

(15) The variator 10, the first, second, and third shift elements B1, K1, B2 and the first and second planetary gear sets RS1, RS2 are arranged between the input shaft 1 and the output shaft 6 of the transmission 100.

(16) The first planetary gear set RS1 includes a first element E11, a second element E12, and a third element E13, and the second planetary gear set RS2 includes a first element E21, a second element E22, and a third element E23, wherein the first element E11, E21 of each of the first and second planetary gear sets RS1, RS2 is a sun gear SO1, SO2, the second element E12, E22 of each of the first and second planetary gear sets RS1, RS2 is a planet carrier or carrier PT1, PT2, and the third element E13, E23 of each of the first and second planetary gear sets RS1, RS2 is a ring gear HO1, HO2.

(17) In a known way, the sun gear SO1, SO2 intermeshes with one or several planet gears PR1, PR2, which are rotatably mounted on the planet carrier PT1, PT2 and intermesh with the ring gear HO1, HO2. The ring gear HO1 of the first planetary gear set RS1 is connectable or coupleable to the transmission housing GG via the first shift element B1 (i.e. first brake B1) and the ring gear HO2 is connectable or coupleable to the transmission housing GG via the third shift element B2 (i.e. second brake B2).

(18) The variator 10 is a NuVinci variator. As is known, a NuVinci variator has a primary side 11 and a secondary side 12. In addition, it is fixed to the transmission housing. The primary side 11 is rotationally fixed to the input shaft 1 of the transmission 100. The secondary side 12 of the variator 10 is rotationally fixed via a third shaft 3 to the sun gear SO2 of the second planetary gear set RS2.

(19) The sun gear SO1 of the first planetary gear set RS1 is rotationally fixed to the ring gear HO2 of the second planetary gear set RS2 via a fifth shaft 5. In addition, the fifth shaft 5 is fixable to a rotationally fixed component, such as a transmission housing GG. If the second brake B2 is activated, the sun gear SO1 of the first planetary gear set RS1 and the ring gear HO2 of the second planetary gear set RS2 are prevented from turning.

(20) The ring gear HO1 of the first planetary gear set RS1 is rotationally fixed to the carrier PT2 of the second planetary gear set RS2 via a fourth shaft 4. The fourth shaft 4 is also fixable to the transmission housing GG via the first brake B1. Moreover, the fourth shaft 4 is rotationally fixable to the input shaft via the third shift element K1 (i.e. clutch K1). If the first brake B1 is activated, the ring gear HO1 of the first planetary gear set RS1 and the carrier PT2 of the second planetary gear set RS2 are prevented from turning.

(21) The planet carrier PT1 of the first planetary gear set RS1 is rotationally fixed to the output shaft 2, so that the carrier PT1 forms the driven end 2 of the transmission 100.

(22) In this case, a first range of ratios or first mode V1 and a second range of ratios or second mode V2 for forward travel and a third range of ratios or third mode R1 for travel in reverse are implementable in the transmission device 100 by selective control of the first, second, and third shift elements B1, K1, B2. The changeover between the first, second, and third modes V1, V2, R1 takes place by the alternate opening and closing of two of the first, second, and third shift elements B1, K1, B2 at a speed-synchronized point.

(23) The first and second planetary gear sets RS1, RS2 are arranged axially adjacent to each other in order to enable the transmission device 100 to be in an installation-space-favorable manner in the radial direction. The first planetary gear set RS1 is arranged axially between the variator 10 and the second planetary gear set RS2.

(24) Through the selection of suitable ratios, the sun gear SO1 and the ring gear HO1 of the first planetary gear set are operable at the same circumferential speed, although in opposite directions, so that the output carrier PT1 is at a standstill, i.e., the rotational speed of the output carrier PT1 is zero. If the rotational speed of the sun gear SO1 of the first planetary gear set RS1 is now changed by an adjustment of the variator ratio, the carrier PT1 begins to turn. The vehicle starts. In this way, a launch clutch is omitted in an advantageous way.

(25) FIG. 2 shows a shift pattern of the transmission device 100, in table form. As shown in the shift pattern, in order to implement the first range of ratios V1 for forward travel, the first shift element B1 is to be engaged, while the second and third shift elements K1, B2 are in the disengaged operating condition. If there is an appropriate demand for implementing the second range of ratios V2 for forward travel, the first shift element B1 is to be disengaged if the first range of ratios V1 for forward travel is presently engaged, the second shift element K1 is to be engaged, and the third shift element B2 is left in the disengaged operating condition. However, if there is an appropriate demand for implementing the third range of ratios R1 for travel in reverse, the third shift element B2 is to be engaged, while the first and second shift elements B1, K1 are to be transferred into or kept in the disengaged operating condition, respectively.

(26) When the first range of ratios V1 for forward travel is engaged, the total torque introduced into the transmission device 100 via the input shaft 1 is guided via the variator 10 in the direction of the output shaft 2 without power splitting, whereby the first range of ratios V1 is a so-called direct mode, the spread of gear ratios of which corresponds to the spread of gear ratios of the variator 10.

(27) When the second range of ratios V2 for forward travel is engaged, a lesser first share of the torque introduced into the transmission device 100 via the input shaft 1 is guided via the variator 10 in the direction of the output shaft 2 and a greater second share of the torque is guided into the second planetary gear set RS2 via the clutch K1 and the fourth shaft 4. Therefore, the power flow in the second range of ratios V2 takes place in a power-split manner.

(28) When the third range of ratios R1 for travel in reverse is engaged, the total torque introduced into the transmission device 100 via the input shaft 1 is guided via the variator 10 in the direction of the output shaft 2 without power splitting, whereby the third range of ratios R1 is also a so-called direct mode, the spread of gear ratios of which corresponds to the spread of gear ratios of the variator 10.

(29) A ratio of the transmission device 100 is continuously variable within each of the first, second, and third modes V1, V2, R1 via the variator 10.

(30) FIG. 3 shows the transmission in a nested gear set arrangement, i.e., the second planetary gear set RS2 is arranged radially outside the first planetary gear set RS1. This is possible due to the fixed sun gear-ring gear coupling, i.e., the fixed connection between the sun gear SO2 of the second planetary gear set RS2 and the ring gear HO1 of the first planetary gear set RS1. As a result, an even more axially compact version of the transmission 100 is possible.

(31) FIG. 4 shows a shift pattern, in table form, of the transmission device 100 according to the embodiment in FIG. 3. The shift pattern is identical to the shift pattern according to FIG. 2 such that reference can be made to the comments made with respect to FIG. 2.

(32) FIG. 5 shows the transmission device 100 in one further embodiment. The transmission 100 includes a plus planetary gear set, wherein the second planetary gear set RS2 is the plus planetary gear set in FIG. 5.

(33) The following nomenclature applies for a plus planetary gear set: the first element is the sun gear, the second element is the ring gear, and the third element is the planet carrier or carrier. Therefore, the carrier connection and the ring gear connection are simultaneously interchanged and the value of the stationary transmission ratio is increased by the value one.

(34) In FIG. 5, the second planetary gear set RS2 includes the same sun gear SO2, inner and outer planet gears PR21, PR22, which are rotatably mounted on the planet carrier PT2 (third element E23), and a ring gear HO2 (second element E22). Due to the interchange, the planet carrier PT2 of the second planetary gear set RS2 is rotationally fixed to the sun gear SO1 of the first planetary gear set RS1 and the ring gear HO1 of the first planetary gear set RS1 is rotationally fixed to the planet carrier PT2 of the second planetary gear set RS2. The planet carrier PT2 of the second planetary gear set RS2 is connectable or coupleable to the first brake B1 and to the clutch K1.

(35) Moreover, the driven end 2 is formed by the second element E12 of the first planetary gear set.

(36) The shift pattern explained with reference to FIG. 2 applies for the embodiments according to FIG. 5.

(37) FIGS. 6 to 8 show the transmission 100 in a hybrid application in three embodiments. The input shaft 1, in particular, is suitable for the connection of an electric machine EM.

(38) The transmission according to FIG. 6 includes an electric machine EM, a stator S of which is rotationally fixed to the rotationally fixed component GG, while a rotor R of the electric machine EM is rotationally fixed to the input shaft 1. Moreover, the input shaft 1 is rotationally fixable, at the mounting interface 1-A, via an intermediate separating clutch K0 which is a lamellar shift element in this case, to a connecting shaft AN which, in turn, is connected to a crankshaft of the drive machine (not represented). Due to the rotationally fixed connection of the rotor R to the input shaft 1, the electric machine EM is located coaxially to the input shaft 1.

(39) Purely electric driving is implementable via the electric machine EM, wherein, in this case, the separating clutch K0 is disengaged in order to decouple the input shaft 1 from the connecting shaft AN and to not entrain the internal combustion engine. All continuously variable modes are also usable electrically. A start into the internal combustion engine-driven modes is always possible. For the rest, the embodiment according to FIG. 6 corresponds to the variant according to FIG. 1, and therefore reference is made to the description thereof.

(40) Moreover, FIG. 7 shows a schematic view of a transmission 100 according to a further design option of the invention, which largely corresponds to the preceding variant represented in FIG. 7. The difference is that the electric machine EM is not arranged coaxially, but rather axially offset with respect to the input shaft 1. Consequently, a rotor (not represented in detail in this case) of the electric machine EM and the input shaft 1 are also not connected to each other in a rotationally fixed manner, but rather are coupled to each other via an intermediate spur gear stage SRS. In this case, a spur gear SR1 of the spur gear stage SRS is located on the input shaft 1 in a rotationally fixed manner and intermeshes with a spur gear SR2 which is arranged, in a rotationally fixed manner, on an input shaft EW of the electric machine EM. This input shaft EW then establishes the connection to the rotor within the electric machine EM. For the rest, the embodiment according to FIG. 7 corresponds to the variant according to FIG. 6, and therefore reference is made to the description thereof.

(41) In addition, FIG. 8 shows a schematic of a transmission 100 according to a further embodiment of the invention, which also essentially corresponds again to the variant according to FIG. 4. As is already the case with the embodiment according to FIG. 7, the electric machine EM is not arranged coaxially, however, but rather axially offset with respect to the input shaft 1. A rotationally fixed coupling between the input shaft 1 and a rotor (not represented) of the electric machine EM is achieved in this case via a flexible traction drive mechanism ZT which is preferably a chain drive. This flexible traction drive mechanism ZT couples the input shaft 1 to an input shaft EW of the electric machine EM in this case. Otherwise, the variant according to FIG. 8 corresponds to the embodiment according to FIG. 6, and therefore reference is made to the description thereof.

(42) With the aid of the embodiments according to the invention, a transmission having a compact design and good efficiency can be implemented.

(43) Modifications and variations can be made to the embodiments illustrated or described herein without departing from the scope and spirit of the invention as set forth in the appended claims.

REFERENCE CHARACTERS

(44) 1 input shaft 2 output shaft 3 third shaft 4 fourth shaft 5 fifth shaft 10 variator unit, variator, NuVinci variator 100 power-split continuously variable transmission device, continuously variable planetary transmission An connecting shaft B1 first shift element, brake B2 third shift element, brake E11 first element E12 second element E13 third element E21 first element E22 second element E23 third element EM electric machine HO1 first ring gear HO2 second ring gear K0 separating clutch K1 second shift element, clutch RS1 first planetary gear set RS2 second planetary gear set SO1 first sun gear SO2 second sun gear PR1 planet gear PR2 planet gear PR21 inner planet gear PR22 outer planet gear PT1 first planet gear carrier, carrier PT2 second planet gear carrier, carrier R1 third mode, reverse R rotor S stator SRS spur gear stage SR1 spur gear SR2 spur gear ZT flexible traction drive mechanism V1 first mode, forward V2 second mode, forward