The invention concerns a dual clutch transmission for use in motor vehicles, comprising two clutches, two sub-transmissions wherein each sub-transmission comprises at least one input shaft and wherein the two input shafts are arranged on a drive input side on an input shaft axis, an output shaft on a drive output side of the transmission which is the drive output shaft of both sub-transmissions, a plurality of wheel planes and in particular at most seven wheel planes and a plurality of shifting elements, in particular at most seven shifting elements, and a countershaft arrangement having at least one countershaft axis on which at least two countershafts are arranged, and in which one of the countershafts extends in the axial direction of the transmission over all the wheel planes whereas the other countershaft, which is a hollow shaft, is arranged parallel to and coaxially with the first countershaft, on which transmission elements of two wheel planes are arranged and connected in a fixed manner, and a shifting element for coupling the two countershafts is provided, and wherein by means of the transmission six forward gears including an overdrive gear and a direct gear can be obtained, such that the direct gear can be obtained by actuating one shifting element and the overdrive gear can be obtained by actuating at least one shifting element.
The invention also concerns a method for operating a dual clutch transmission, such that the dual clutch transmission comprises two clutches, a plurality of wheel planes and in particular at most seven wheel planes, a plurality of shifting elements and in particular at most seven shifting elements, and a countershaft arrangement having at least one countershaft axis on which at least two countershafts are arranged, in which one of the countershafts extends in the axial direction of the transmission over all the wheel planes whereas the other countershaft, which is a hollow shaft, is arranged parallel to and coaxially with the first countershaft, on which transmission elements of two wheel planes are arranged and connected in a fixed manner, and a shifting element for coupling the two countershafts is provided, and wherein by means of the transmission six forward gears including an overdrive gear and a direct gear can be obtained, such that the direct gear can be obtained by actuating one shifting element and the overdrive gear can be obtained by actuating at least one shifting element.
The invention further concerns a method for operating a dual clutch transmission, wherein a first gear is obtained by closing a first clutch and also closing the third and sixth shifting elements, and wherein a second gear is obtained by closing a second clutch and also closing the second shifting element, and wherein a third gear is obtained by closing the first clutch and also closing the third shifting element, and wherein a fourth gear is obtained by closing the second clutch and also closing the fifth shifting element.
Transmissions for motor vehicles are designed, among others, as so-termed dual clutch transmissions in which in each case an input shaft is associated with a sub-transmission and in which the input shafts of the two sub-transmissions can be connected by a respectively associated powershift element with a drive input such as a combustion engine or an electric motor, the two powershift elements then being combined in the form of a dual clutch. The gears that can be produced by means of such a transmission are then divided in alternation between the two sub-transmissions, so that for example one sub-transmission produces the odd-numbered gears and the corresponding other sub-transmission produces the even-numbered gears. It is also known to produce the individual gear steps by means of one or more gearwheel stages or planes, each with a different gear ratio step. By virtue of corresponding shifting elements these can be connected into the force or torque flow between the drive input and the drive output, so that a corresponding desired transmission ratio is produced in each case between the drive input and the drive output.
Thanks to the alternate division of the gears between the two sub-transmissions it is possible, while driving in a gear associated with one of the sub-transmissions, already to preselect a subsequent gear in the respective other sub-transmission by appropriate actuation of the shifting devices, so that an eventual shift to the subsequent gear is enabled by opening the powershift element of the one sub-transmission and, shortly after, closing the powershift element of the other sub-transmission. In this way the gears or gear steps of the transmission can be shifted under load, which improves both the ability of the motor vehicle to accelerate and the comfort of gearshift processes for the vehicle's driver, since the gearshift takes place essentially without traction force interruption.
Such dual clutch transmissions can also be made with an intermediate countershaft arrangement in addition to the drive input and the drive output, so that a more compact structure is produced in the axial direction.
Such a transmission 1 is known, for example, from DE 10 2004 043 387 A1.
This has the disadvantage that the number of gears that can be obtained with the transmission corresponds essentially to the number of wheel planes, i.e. for example with seven wheel planes including a reversing gear stage a total of six forward gears are available, including a direct gear.
An objective of the present invention is therefore to make available a dual clutch transmission and a method for operating a dual clutch transmission, which can provide at least one further gear. A further objective of the present invention is to provide an alternative dual clutch transmission and an alternative method for operating a dual clutch transmission.
The present invention achieves these objectives with a dual clutch transmission for use in motor vehicles, which comprises two clutches, two sub-transmissions each of which comprises at least one input shaft, and wherein on a drive input side the two input shafts are arranged on an input shaft axis, an output shaft on a drive output side of the transmission which is the drive output shaft of both sub-transmissions, a plurality of wheel planes and in particular at most seven wheel planes, a plurality of shifting elements and in particular at most seven shifting elements, and a countershaft arrangement with at least one countershaft axis on which at least two countershafts are arranged, one of the countershafts extending in the axial direction of the transmission over all the wheel planes whereas the other of the two countershafts, which is a hollow shaft, is arranged parallel to and coaxially with the first countershaft, on which transmission elements of two wheel planes are arranged in fixed connection and wherein a shifting element is provided for coupling the two countershafts, and such that by means of the transmission six forward gears including an overdrive gear and a direct gear can be obtained, in which the direct gear can be obtained by actuating one shifting element and the overdrive gear by actuating two shifting elements, in that besides the six gears an additional gear, in particular a forward gear, can be obtained in the transmission, this additional gear having a gear ratio greater than 1 and being obtained by actuating only one shifting element, and in particular wherein the two shifting elements are arranged on that side of the shifting element for actuating the additional gear which faces toward the drive input side.
The present invention also achieves the objectives with a method for operating a dual clutch transmission, such that the dual clutch transmission comprises: two clutches, a plurality of wheel planes and in particular at most seven wheel planes, and a plurality of shifting elements and in particular at most seven shifting elements, and a countershaft arrangement with at least one countershaft axis on which at least two countershafts are arranged, one of the countershafts extending in the axial direction of the transmission over all the wheel planes whereas the other of the two countershafts, which is a hollow shaft, is arranged parallel to and coaxially with the first countershaft, on which transmission elements of two wheel planes are arranged in fixed connection and wherein a shifting element is provided for coupling the two countershafts, and such that by means of the transmission six forward gears including an overdrive gear and a direct gear can be obtained, in which the direct gear can be obtained by actuating one shifting element and the overdrive gear by actuating at least one shifting element, in that a gear additional to the six gears already available has a gear ratio greater than unity and is formed by the actuation of only one shifting element whereas the overdrive gear is obtained by actuating at least two shifting elements, in particular such that the two shifting elements are arranged on that side of the shifting element for actuating the additional gear which faces toward the drive input side.
The present invention also achieves the objectives with a method for operating a dual clutch transmission, such that a first gear is obtained by closing a first clutch and also closing the third and sixth shifting elements, and a second gear is obtained by closing the second clutch and the sixth shifting element, and a third gear is obtained by closing the first clutch and the second shifting element, and a fourth gear is obtained by closing the second clutch and the fifth shifting element, in that a fifth gear is obtained by closing the second clutch and the fourth shifting element, and a sixth gear, particularly in the form of a direct gear, is obtained by closing the first clutch and the first shifting element, and a seventh gear in the form of an overdrive gear is obtained by closing the second clutch and also closing the first and third shifting elements.
The invention also achieves the objectives with a motor vehicle, in particular a passenger car or a truck, having a transmission according to the invention.
One of the advantages achieved thereby is that without substantial structural modifications an additional gear can be made available, which is advantageous for the use of the transmission in a variety of vehicles. A further advantage is that in this way at least partial powershiftability of the transmission is achieved. Another advantage is that with the same structural effort and expense a greater spread or smaller gear intervals are made possible.
The term “wheel stage” or “wheel plane” in the description and particularly in the claims is preferably understood to mean essentially two transmission elements that co-operate to transmit torques from one transmission element to the other transmission element, such that preferably a stepped-down or stepped-up ratio is obtained in particular for transmission shafts that co-operate with the transmission elements.
The term “shifting element” in the description and particularly in the claims is preferably understood to mean a device which has at least an open and a closed condition, such that in the open condition the device does not transmit any torque and in the closed condition the device can transmit a torque between two devices that co-operate with the device or shifting element.
The term “shifting device” in the description and particularly in the claims is preferably understood to mean at least one shifting element and at least one shifting element actuating device for actuating the at least one shifting element.
The term “transmission element” in the description and particularly in the claims is preferably understood to mean a device by means of which force and/or torque can be transmitted. Here, transmission elements can preferably be in the form of wheels, preferably gearwheels and in particular spur gears, bevel gears, worm gears or the like.
The term “double shifting element” in the description and particularly in the claims is preferably understood to mean two shifting elements and two separate shifting element actuating devices, particularly in the form of sliding sleeves, which can be actuated in such manner that at least one of the two shifting elements is closed and at the same time the respective other shifting element is open.
Other advantageous embodiments, features and advantages of the invention are described below.
Expediently, the overdrive gear is obtained by means of the two wheel planes closest to the drive input side. This keeps the path as short as possible, so that a reliable force and torque transmission from the drive input side to the drive output side of the dual clutch transmission is enabled.
Advantageously, one of the two shifting elements for actuating the overdrive gear is arranged on the input shaft axis and the other of the two shifting elements is arranged on the countershaft axis. In this way the axial fitting space of the shifting elements for obtaining the overdrive gear can be reduced.
Advantageously, the additional gear and the overdrive gear can be obtained by actuating the same clutch. This allows the additional gear to be obtained in a simple manner.
Expediently, the overdrive gear and the direct gear can be obtained by means of the same shifting element, especially when the shifting element is arranged next to the drive input side in the transmission. In this way the shifting element, when it is arranged next to the drive input side, can be maintained simply. At the same time the number of shifting elements for producing the gears is reduced.
Expediently, in the shifting sequence from high to low gear ratios the additional gear can be engaged before, in particular immediately before the direct gear. In this way the lower gears as far as the gear ratio concerned can remain unchanged as regards their actuation of clutches and shifting elements.
Advantageously, the shifting elements for obtaining the direct gear and/or the overdrive gear are arranged close to at least two other shifting elements on the drive output side of that shifting element for obtaining the direct gear and/or the overdrive gear which is arranged farthest toward the drive output side. What this achieves is that the shifting elements for the direct gear and the overdrive gear are not arranged in the area of the drive output side.
Expediently, the additional gear can be partially powershifted via the direct gear by means of a support gearshift. This gives at least partial powershiftability.
Expediently, the additional gear is designed to be the fifth forward gear, the direct gear being the sixth forward gear and/or the overdrive gear being the seventh forward gear. One of the advantages achieved thereby is that as regards their actuation, the first four gears do not have to be modified, and this reduces the complexity for producing the transmission, and hence also the production costs.
Expediently one of the wheel planes, in particular the wheel plane closest to the drive output side, is designed as the reversing gear stage. One of the advantages achieved thereby is that at least one reversing gear can be made available by the transmission, which is advantageous as regards the flexibility of the transmission for use in a variety of vehicles.
Expediently, the shifting element next to and near the drive output side is made as a single shifting element and/or at least two and in particular all of the other shifting elements are in the form of double shifting elements. If all the other shifting elements are made as double shifting elements, the production complexity and hence the production costs of the transmission are reduced. For example, if the reversing gear stage is actuated by means of the single shifting element, this enables the reversing gear stage to be coupled or connected into the torque transmission path of the transmission particularly reliably. At the same time the single shifting element can be maintained more simply on the drive output side.
Expediently, the first six shifting elements beginning from the drive input side are in each case arranged in pairs, in alternation on the input shaft axis and the countershaft axis, particularly in each case in the form of double shifting elements. One of the advantages achieved thereby is that the fitting space in the axial direction of the dual clutch transmission can be reduced in that way.
Expediently, between the two shifting elements for engaging the overdrive gear there is arranged at least one further shifting element in the sequence of shifting elements along the axis of the transmission. In this way the flexibility of the transmission can be increased still more as regards the coupling of various wheel planes for the production of gears.
Advantageously, more than half of the shifting elements are arranged on the input shaft axis of the transmission. In this way the fitting space for a countershaft arrangement can be reduced considerably.
Advantageously, the fifth gear is engaged partly under load by way of the sixth gear by means of a support gearshift. This allows at least partial powershiftability to be achieved in a simple manner.
Further important features and advantages of the invention emerge from the subordinate claims, from the drawings and from the associated figure descriptions relating to the drawings.
It is understood that the features mentioned above and those still to be explained can be used not only in the combination indicated in each case, but also in other combinations or as stand-alone features, without going beyond the scope of the present invention.
Preferred designs and embodiments of the present invention are illustrated in the drawings and will be explained in more detail in the description given below, wherein the same indexes denote the same, or similar, or functionally equivalent components or elements.
The figures show, in each case schematically:
In
Furthermore, the transmission comprises two sub-transmissions 2, 3. The first sub-transmission 2 is coupled with the first input shaft EW1 and the second sub-transmission with the second input shaft EW2.
In addition the transmission 1 has an input shaft axis 4 on which the two input shafts EW1, EW2 are arranged. Downstream in relation to the torque and force flow from the drive input side AN of the transmission 1 and beginning from the two clutches KL1, KL2, the transmission 1 comprises first a first wheel plane I, then a second wheel plane II, a first shifting element A, a second shifting element B, a third wheel plane III, a fourth wheel plane IV, a fifth wheel plane V, a fifth shifting element E, a sixth shifting element F, a sixth wheel plane VI, a seventh wheel plane VII and a seventh shifting element G. Each of the wheel planes I, II, III, IV, V, VI and VII has transmission elements, in particular in the form of gearwheels, each of which is and/or can be connected to a shaft of the transmission 1.
Parallel to the input shaft axis 4 is arranged a countershaft axis 5 for a countershaft arrangement 6. The countershaft arrangement 6 comprises a countershaft VW1 in the form of a solid shaft with a countershaft VW2 in the form of a hollow shaft arranged coaxially with and parallel to it. Between the input shaft axis 4 and the countershaft axis 5 the seventh wheel plane VII has an intermediate wheel ZR for reversing the rotation direction, so that by means of the drive output shaft AW and with the same rotation direction of one of the input shafts EW1, EW2 a reversed rotation direction is enabled for the provision of at least one reversing gear. Thus, the seventh wheel plane VII is designed as the reversing gear stage.
Beginning from the drive input side AN, the countershaft axis 5 has the first wheel plane I, the second wheel plane II, the third wheel plane III, a third shifting element C, a fourth shifting element D, the fourth wheel plane IV, the fifth wheel plane V, the sixth wheel plane VI and the seventh wheel plane VII.
Below, the seven shifting elements A, B, C, D, E, F and G will now be described.
The first shifting element A is arranged on the input shaft axis 4 and is connected on one side to the first input shaft EW1 and to a transmission element of the second wheel plane II, and on the other side to the drive output shaft AW, and when actuated it forms a connection for the transmission of force and torques between the input shaft EWI, the second wheel plane II and the drive output shaft AW.
The second shifting element B is arranged on the input shaft axis 4 and is connected on one side to a transmission element of the third wheel plane III and on the other side to the drive output shaft AW. When actuated, it couples the drive output shaft AW to the third wheel plane III.
The third shifting element C is arranged on the countershaft axis 5 and is connected on one side to the first countershaft VW1 and on the other side to the second countershaft VW2. When actuated, it couples the first countershaft VWI to the second countershaft VW2.
The fourth shifting element D is arranged on the countershaft axis 5 and is connected on one side to a transmission element of the fourth wheel pane IV and on the other side to the first countershaft VW1. When actuated, it couples the first countershaft VW1 to the fourth wheel plane IV.
The fifth shifting element E is arranged on the input shaft axis 4 and, when actuated, it couples the first countershaft VW1 to the drive output shaft AW by way of the fifth wheel plane V.
The sixth shifting element F is arranged on the input shaft axis 4 and, when actuated, it couples the first countershaft VW1 to the drive output shaft AW by way of the sixth wheel plane VI.
The seventh shifting element G is arranged on the input shaft axis 4 and, when actuated, it couples the first countershaft VW1 to the drive output shaft AW by way of the seventh wheel plane VII.
The shifting elements A and B, and C and D, and E and F are in each case combined in respective double shifting elements and can in each case be actuated by a respective shared shifting element actuating device. The seventh shifting element G is a single shifting element.
On the first countershaft VW1 are arranged in a fixed manner transmission elements of the first wheel plane I, the fifth wheel plane V, the sixth wheel plane VI and the seventh wheel plane VII.
On the second countershaft VW2 are arranged in a fixed manner transmission elements of the second wheel plane II and the third wheel plane III. On the drive output shaft AW is arranged in a fixed manner the transmission element of the fourth wheel plane IV. On the first input shaft EW1 is arranged in a fixed manner the transmission element of the second wheel plane II on the input shaft axis 4, and on the second input shaft EW2 is arranged in a fixed manner the transmission element of the first wheel plane I.
The transmission 1 according to
In
Perpendicularly downward are shown first the seven forward gears, denoted by the indexes Vi to V7, and a reversing gear denoted by R. Cells in the shifting matrix left empty, for example for the forward gear V1 the shifting elements A, B, E and G and the clutch KL2, indicate that the corresponding shifting element or clutch is in this case open, i.e. that here the shifting element or clutch is transmitting no forces or torques between the respective shaft or shafts associated with or connected to the shifting element or clutch concerned. A cell containing a dot in the shifting matrix indicates that the corresponding shifting element or clutch is actuated or closed, for example in the shifting matrix for the forward gear V1 the clutch KL1 and the shifting elements C and F.
Unless otherwise described in what follows, all the clutches KL1 and KL2 and all the shifting elements A to G are in each case open.
To obtain the first forward gear V1 of the transmission 1, according to
To obtain the second forward gear V2, the clutch KL2 and the shifting element F are closed. The absolute gear ratio is 4.79 and the relative gear ratio is 1.44.
To obtain the third forward gear V3, the clutch KL1 and the shifting element B are dosed. The absolute gear ratio is 2.67 and the relative gear ratio is 179.
To obtain the fourth forward gear V4, the clutch KL2 and the shifting element E are closed. The absolute gear ratio is 1.61 and the relative gear ratio is 1.66.
To obtain the fifth forward gear V5, the clutch KL2 and the shifting element D are dosed. The absolute gear ratio is 1.32 and the relative gear ratio is 1.22.
To obtain the sixth forward gear V6, the clutch KL1 and the shifting element A are closed. The absolute gear ratio is 1.00 and the relative gear ratio is 1.61.
To obtain the seventh forward gear V7, the clutch KL2 and the shifting elements A and C are closed. The absolute gear ratio is 0.70 and the relative gear ratio is 1.44.
To obtain the reversing gear R, the clutch KL1 and the shifting elements C and C are closed.
The total relative gear ratio amounts to 9.88. In
All told, the transmission elements can in particular be in the form of gearwheels, preferably spur gears, so that the wheel planes I to VII are spur gear stages. To obtain various forward and reversing gears, i.e. various gear ratios, the spur gear stages and in particular their gearwheels can correspondingly provide different gear ratios.
In summary the present invention offers, among other things, the advantage that at least one additional gear can be made available with the same fitting space. A further advantage is that a larger spread or smaller gear intervals are made possible.
Although the present invention has been described above with reference to preferred example embodiments, it is not limited to these but can be modified in many ways.
Number | Date | Country | Kind |
---|---|---|---|
10 2015 202 350.8 | Feb 2015 | DE | national |
This application is a National Stage completion of PCT/EP2016/050334 filed Jan. 11, 2016, which claims priority from German patent application serial no. 10 2015 202 350.8 filed Feb. 10, 2015.
Filing Document | Filing Date | Country | Kind |
---|---|---|---|
PCT/EP2016/050334 | 1/11/2016 | WO | 00 |