Motor vehicle drive device
By optimizing the support and gear design of the transmission shaft, combining the fixed-floating support and oblique meshing gear stage, the problem of difficulty in taking into account both efficiency and comfort in the prior art is solved, and high efficiency and low noise driving power transmission is achieved.
Patent Information
- Application Number
- CN202380043801.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2022-08-17
- Filing Date
- 2023-07-18
- Publication Date
- 2025-01-14
AI Technical Summary
In the pursuit of high efficiency and comfort, existing motor vehicle drive systems are difficult to take into account, especially the combination of end surface overlap and longitudinal overlap in gear design leads to acoustic disadvantages and deterioration of comfort during power transmission, and additional sound insulation materials increase the vehicle. Weight affects efficiency.
A motor vehicle drive system is designed, by optimizing the support and tooth design of the transmission shaft, using fixed-floating support and obliquely engaged cylindrical gear stage, combined with appropriate gear overlap and inclination angle, to achieve efficient transmission of driving power. and low noise transmission.
A drive system with high efficiency and comfort is achieved, reducing towing losses, extending the service life of fixed bearings, and offsetting axial forces through oblique meshing gear stages, improving the efficiency and acoustic performance of power transmission.
Smart Images
Figure CN119317789A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to an electric motor vehicle drive system for overcoming driving resistance of a motor vehicle, such as rolling resistance, air resistance and the like, and a motor vehicle comprising such a drive system. DE 10 2019 127 242 A1 discloses an electric drive device for a motor vehicle comprising a transmission according to the preamble of claim 1 and a drive arrangement comprising a transmission and an electric motor. Background Art
[0002] The general requirement for the drive device of a motor vehicle is to provide the required driving power comfortably and efficiently. Here, these two characteristics or their realization can affect each other adversely. The present invention is then explained by means of a motor vehicle drive system including a gear transmission, wherein the gears of the transmission have so-called involute teeth. It is known in such a toothing that a so-called high toothing, that is, a gear pair with a profile overlap of >= 2.0 and a longitudinal overlap of >= 2.0 can realize a particularly comfortable drive device. Although the efficiency can be improved relative to the high toothing explained above in a gear pair with a smaller profile overlap and another overlap combination, this usually leads to acoustic disadvantages and thus worsens the comfort during power transmission. Further in the motor vehicle drive device, it is also possible in principle to insulate the noise by means of additional sound insulation materials, but it has an adverse effect on the vehicle weight, which means additional costs and thus worsens the efficiency of the motor vehicle. Summary of the invention
[0003] The present invention, on the other hand, proposes a motor vehicle drive system which likewise allows the transmission of drive power with high efficiency and high comfort, which object is achieved by the subject matter according to claim 1 and by a motor vehicle according to claim 9, wherein preferred further developments of the invention are respectively the subject matter of the dependent claims. In the present invention, it is proposed in particular that not only the toothing of the individual gears but also the entire system, in particular the mounting of the transmission shaft in the transmission housing and the combination of the bearing design and the toothing design, are considered, so that a drive system with high comfort and high efficiency is produced.
[0004] In the sense of the present invention, a motor vehicle drive system is understood to be a system for driving a motor vehicle, preferably a passenger car, in which a drive power for overcoming driving resistances such as friction resistance, rolling resistance, air resistance and so-called acceleration resistance is provided by means of a preferably electromechanical energy converter. In other words, such an electromechanical energy converter in the sense of the present invention is understood to be a drive motor, in particular an electric motor / generator, wherein such drive motors are known in various designs.
[0005] Furthermore, the motor vehicle drive system has a traction transmission device, wherein the transmission device is designed to transmit drive power and to adapt the drive power to a load requirement of the motor vehicle, in particular caused by driving resistance. The traction transmission device is thereby designed to transmit drive power in the form of rotational speed and torque to a motor vehicle axle drive. The motor vehicle axle drive is understood here in particular to be a motor vehicle drive shaft, in particular a front axle or a rear axle.
[0006] The traction transmission arrangement has a traction transmission housing arrangement, in particular, the traction transmission housing arrangement comprises a plurality of components and is preferably also designed to accommodate a drive motor. A traction transmission drive shaft is rotatably mounted in the traction transmission housing, wherein the traction transmission drive shaft can be understood as a first shaft or input shaft into the traction transmission arrangement with respect to the drive direction of power transmission from the drive motor to the motor vehicle axle drive, the so-called engine drive.
[0007] In a first embodiment of the invention, the traction transmission drive shaft is connected to the drive motor in a rotationally fixed manner, preferably oriented coaxially therewith and further preferably directly coupled thereto in a rotationally fixed manner. In another embodiment, the traction transmission drive shaft is selectively connectable to the drive motor in a rotationally fixed manner, preferably by means of a clutch device. In particular, a permanent rotationally fixed connection of the drive motor to the traction transmission drive shaft allows a saving in bearing space and a reduction in drag losses with a selectively coupleable drive motor.
[0008] In addition to the traction transmission drive shaft, the traction transmission arrangement also has a traction transmission intermediate shaft, which is arranged downstream of the traction transmission drive shaft with respect to the driving direction of the engine drive, preferably directly downstream thereof. The traction transmission intermediate shaft is rotatably supported in the traction transmission housing arrangement and is axially parallel to the traction transmission drive shaft and is radially spaced apart from the traction transmission drive shaft. Furthermore, the traction transmission arrangement also has a traction transmission output shaft, which is arranged downstream of the traction transmission intermediate shaft with respect to the driving direction of the engine drive, preferably directly downstream thereof. Furthermore, the traction transmission output shaft is rotatably supported in the traction transmission housing arrangement and is preferably axially parallel to two other traction transmission shafts and is radially spaced apart from the two other traction transmission shafts.
[0009] In order to form a traction transmission device, i.e., in particular a transmission device, comprising two gear stages for transmitting power from a drive motor to a motor vehicle axle drive, a traction transmission drive gear is arranged on the traction transmission drive shaft, the traction transmission drive gear is in meshing engagement with a first traction transmission intermediate gear, which is arranged on the traction transmission intermediate shaft. The traction transmission drive gear and the first traction transmission intermediate gear thereby form a first gear stage with the traction transmission drive shaft and the traction transmission intermediate shaft, by means of which the drive power can be transmitted from one of the shafts to the other of the shafts. A second traction transmission intermediate gear is also arranged on the traction transmission intermediate shaft, the second traction transmission intermediate gear is in meshing engagement with a traction transmission output gear, which is arranged on the traction transmission output shaft. The second traction transmission intermediate gear and the traction transmission output gear thereby form a second gear stage with the traction transmission intermediate shaft and the traction transmission output shaft, by means of which the drive power can be transmitted from one of the shafts to the other of the shafts.
[0010] The traction transmission housing arrangement has a traction transmission housing and a traction transmission cover as main components. In particular, the traction transmission housing and the traction transmission cover are designed to receive bearings, preferably rolling bearings, in order to rotatably support the traction transmission drive shaft, the traction transmission intermediate shaft and the traction transmission output shaft relative to the traction transmission housing arrangement. The traction transmission housing is preferably designed in such a way that, in the assembled state of the motor vehicle drive system, it covers at least one gear stage of the gear stages, preferably two gear stages, in the axial direction of the traction transmission drive shaft. It is further preferred that the traction transmission cover is designed as a so-called bearing cover. The traction transmission cover can also be designed as a multi-part component like the traction transmission housing.
[0011] In order to achieve sufficient rigidity in the mounting of the transmission shafts (traction transmission drive shaft, traction transmission output shaft, traction transmission intermediate shaft), the three traction transmission shafts are each mounted in a traction transmission housing arrangement with a so-called fixed-floating bearing. In the sense of the invention, a fixed-floating bearing is understood in particular to be a bearing which has two bearing locations for the shaft relative to the housing, wherein one of these bearing locations is designed to receive axial and radial forces and the other is designed to receive radial forces, wherein axial and radial can each be understood with respect to the axis of rotation of the shaft to be supported, and wherein the bearing location at which the axial forces can be received can be understood as a fixed bearing. In this case, a single such bearing location can also have a plurality of bearings, preferably a plurality of rolling bearings, and in particular a so-called fixed bearing can have a radial and an axial bearing.
[0012] The concept of such a fixed-floating bearing is known from the prior art. It is therefore further proposed that such a fixed-floating bearing each has at least one fixed bearing for absorbing axial forces, wherein at least two of these fixed bearings are arranged in the traction transmission cover or supported by the traction transmission cover and positioned relative to the traction transmission housing. In particular, in such a design of the motor vehicle drive system, a simple assembly of the traction transmission device can be achieved.
[0013] In a preferred embodiment, all fixed bearings provided for supporting the traction transmission drive shaft, the traction transmission intermediate shaft and the traction transmission output shaft are provided in the traction transmission cover, or all fixed bearings are supported by the traction transmission cover and thus positioned and held relative to the traction transmission housing by the traction transmission cover. In particular, such a design of the present invention enables simple assembly of the traction transmission device.
[0014] In a preferred embodiment of the invention, the traction transmission drive gear and the first traction transmission intermediate gear engage with each other for the transmission of drive power and thus form a first traction transmission gear stage. It is further preferred that the lateral overlap of the first traction transmission gear stage is greater than 1.70, preferably greater than or equal to 1.76 and preferably the lateral overlap is less than 1.90 and preferably less than or equal to 1.84. It is further preferred that the longitudinal overlap of the first traction transmission gear stage is greater than 3.10 and preferably greater than or equal to 3.16 and further preferably the longitudinal overlap is less than 3.30 and preferably less than or equal to 3.24. In particular, in combination with the previously described bearing design (fixed-floating bearing) and the lateral overlap or longitudinal overlap selected in this way, a simple assembly of the traction transmission device and a low-noise transmission of drive power and at the same time a high efficiency in the power transmission result.
[0015] In a preferred embodiment of the invention, the second traction transmission intermediate gear and the traction transmission output gear engage with each other for the transmission of drive power and thus form a second traction transmission gear stage. It is further preferred that the lateral overlap of the second traction transmission gear stage is greater than 1.40, preferably greater than or equal to 1.46 and preferably the lateral overlap is less than 1.60 and preferably less than or equal to 1.54. It is further preferred that the longitudinal overlap of the second traction transmission gear stage is greater than 2.40 and preferably greater than or equal to 2.46 and further preferably the longitudinal overlap is less than 2.50 and preferably less than or equal to 2.54. In particular, in combination with the previously described bearing design (fixed-floating bearing) and the lateral overlap or longitudinal overlap of the second traction transmission gear stage thus selected, a simple assembly of the traction transmission device and a low-noise transmission of drive power and simultaneously high efficiency result.
[0016] In a preferred embodiment, at least two gears of at least one of the two traction transmission gear stages are designed as helical toothed spur gears, preferably with so-called involute toothing, and preferably all gears of these gear stages are designed as such, in particular helical toothed spur gears. In such an embodiment comprising at least two, preferably all, helical toothed spur gears, preferably the first traction transmission intermediate gear comprises first helical teeth with a first inclination angle and the second traction transmission intermediate gear comprises second helical teeth with a second inclination angle. Furthermore, the first and second inclination angles point in opposite directions, so that axial forces occurring in power transmission, in particular due to the inclination angles, at least partially cancel each other out, or axial forces occurring by transmission of drive power point in opposite directions. In particular, by the opposite directions of the axial forces of the first and second traction transmission intermediate gears, in particular the fixed bearing of the fixed-floating bearing of the traction transmission intermediate shaft is relieved of load and the service life of the fixed bearing is thus prolonged and furthermore the power loss, in particular caused by the fixed bearing, can be reduced in this way.
[0017] In a preferred embodiment of the invention, the traction transmission drive shaft is supported in the traction transmission housing arrangement by means of a fixed-floating mount, i.e. a mount having a fixed bearing at least for absorbing axial forces and a floating bearing. Preferably, at least one of the bearings of the fixed-floating mount is arranged only indirectly on the traction transmission drive shaft, preferably the traction transmission drive shaft is received in another shaft, and the floating bearing of the fixed-floating mount of the traction transmission drive shaft is received on the other shaft or is designed to support the other shaft and thereby indirectly supports the traction transmission drive shaft. Preferably, the traction transmission drive shaft is connected to the other shaft in a rotationally fixed manner and preferably by means of a positively locking shaft-hub connection, and particularly preferably a fit, preferably a transition fit and preferably a press fit is provided for positioning the traction transmission drive shaft relative to the other shaft.
[0018] The floating bearing of the fixed-floating mounting of the traction transmission drive shaft is preferably designed as a so-called common floating bearing for the traction transmission drive shaft and for the further shaft, and in particular such a design of the mounting of the traction transmission drive shaft allows particularly efficient support of the shaft.
[0019] It is further preferred that a rolling bearing with balls as rolling elements is provided as the fixed bearing of the fixed-floating bearing of the traction transmission drive shaft, and it is further preferred that the bearing is designed as a so-called four-point bearing and preferably as a so-called deep groove ball bearing. It is further preferred that the fixed bearing also forms a fixed bearing for the other shaft, in particular by connecting the traction transmission drive shaft to the other shaft.
[0020] It is further preferred that a rolling bearing comprising cylindrical rolling elements or preferably balls is provided as a floating bearing of the fixed-floating bearing of the traction transmission drive shaft. Preferably, the floating bearing is designed as a roller bearing and preferably as a deep groove ball bearing. In a preferred embodiment, both the fixed bearing and the floating bearing of the bearing of the traction transmission drive shaft are designed as deep groove ball bearings. In particular, in embodiments comprising such rolling bearings, a high efficiency in power transmission can be achieved. Preferably, the fixed bearing of the bearing of the traction transmission drive shaft is arranged in the traction transmission cover and is in particular fixed to the traction transmission cover.
[0021] It is further preferred that the traction transmission housing is designed in such a way that the drive motor is arranged on or in the traction transmission housing. In particular, such a design can achieve simple assembly of the motor vehicle drive system and high efficiency in transmitting drive power.
[0022] In a preferred embodiment of the motor vehicle drive system, the traction transmission intermediate shaft is supported in the traction transmission housing device by means of a fixed-floating bearing, that is, a bearing comprising a fixed bearing for absorbing axial forces and a floating bearing. It is further preferred that a rolling bearing with balls as rolling elements is provided as a fixed bearing of the fixed-floating bearing of the traction transmission intermediate shaft, and it is further preferred that the bearing is designed as a so-called four-point bearing and preferably as a so-called deep groove ball bearing. It is further preferred that a rolling bearing with cylindrical rolling elements or preferably balls is provided as a rolling bearing of the fixed-floating bearing of the traction transmission intermediate shaft. Preferably, the floating bearing is designed as a roller bearing and preferably as a deep groove ball bearing. In a preferred embodiment, both the fixed bearing and the floating bearing of the bearing of the traction transmission intermediate shaft are designed as deep groove ball bearings. In particular, in an embodiment comprising such rolling bearings, a high efficiency can be achieved during power transmission. Preferably, the fixed bearing of the bearing of the traction transmission drive shaft is arranged in the traction transmission cover.
[0023] In a preferred embodiment, the traction transmission output shaft is supported in the traction transmission housing arrangement by means of a fixed-floating bearing. It is further preferred that the fixed-floating bearing has a fixed bearing or a fixed bearing position and at least one floating bearing, in particular for absorbing axial forces. The fixed-floating bearing preferably for supporting the traction transmission output shaft has, in particular, two or more rolling bearings, wherein the rolling elements of at least two of these rolling bearings are designed as cylindrical rolling elements and preferably these rolling bearings are therefore designed as roller bearings. It is preferred that the fixed-floating bearing of the traction transmission output shaft has, in addition to the two cylindrical roller bearings, rolling bearings designed as fixed bearings, preferably rolling bearings with balls as rolling elements. It is further preferred that the fixed bearing of the bearing of the traction transmission output shaft is designed as a deep groove ball bearing, preferably as a four-point bearing. The fixed bearing is in particular radially free, or in other words, the bearing seat designed to receive the fixed bearing has a smaller diameter on the traction transmission output shaft than the bearing inner ring of the fixed bearing, or it is further preferred that the bearing seat designed to receive the fixed bearing in the traction transmission housing arrangement has a larger diameter than the bearing outer diameter of the fixed bearing. It is further preferred that the roller bearings of the fixed-floating bearing of the traction transmission output shaft are arranged on different sides of the traction transmission output gear in the axial direction. It is further preferred that the fixed bearing of the bearing of the traction transmission output shaft, that is to say in particular a deep groove ball bearing or a four-point bearing, is arranged in the traction transmission cover. In particular, such a design can provide an efficient and rigid mounting of the traction transmission output shaft.
[0024] A motor vehicle is further proposed, which has at least one motor vehicle drive system of the proposed design. In particular, the motor vehicle drive system is designed to drive the motor vehicle in a main driving direction and preferably also opposite to the main driving direction, wherein the main driving direction is to be understood as the forward driving direction of a passenger vehicle. Preferably, the motor vehicle is drivable with only one of these motor vehicle drive systems and is thereby designed as a motor vehicle with front-wheel or rear-wheel drive, and further preferably, the motor vehicle is equipped with two such motor vehicle drive systems and is thereby designed as an all-wheel vehicle.
[0025] In a preferred embodiment, at least the second traction transmission gear stage is designed as a helical gear stage. In particular, the traction transmission output gear comprises an output helical toothing with an output inclination angle and is thus designed as a helical spur gear. Further preferably, the output inclination angle is selected such that the axial forces of the traction transmission output gear which occur through the helical teeth of the traction transmission output gear when the motor vehicle is driven in the forward driving direction are directed in the direction in which the traction transmission output shaft extends, i.e. in the axial direction from the traction transmission cover to the traction transmission housing. In particular, such a design allows efficient transmission of the drive force with high comfort and at the same time the motor vehicle drive system is simple to assemble and can thereby be manufactured at low cost.
[0026] In other words, the basic idea of the invention is to select the tooth overlap of the first spur gear stage (first traction transmission gear stage) and the second spur gear stage (second traction transmission gear stage) in such a way that a high efficiency is achieved with good comfort, in particular good acoustics, when transmitting the drive power. For the proposed motor vehicle drive system, the tooth overlap of the first and second traction transmission gear stages is designed such that the tooth overlap preferably results as follows:
[0027] The first traction transmission gear stage has an end contact ratio in the range of 1.76-1.84 and a longitudinal contact ratio in the range of 3.16-3.24;
[0028] The second traction transmission gear stage has an end surface overlap in the range of 1.46-1.54 and a longitudinal overlap in the range of 2.46-2.54.
[0029] It is further proposed that the inclination direction of the toothing of the second traction transmission gear stage is preferably selected such that the resulting axial force of the traction transmission output gear is directed toward the traction transmission housing during forward travel driven by the engine of the motor vehicle. It is further proposed that the traction transmission output gear is preferably designed as a so-called final drive gear. In the sense of the invention, a so-called final drive gear is understood to be a gear in which an axle differential of a motor vehicle drive shaft is received or which is connected to a differential housing of such an axle differential in a rotationally fixed manner.
[0030] Furthermore, the traction transmission drive gear and thereby also the first traction transmission intermediate gear are preferably designed as helical spur gears, like the preferred traction transmission output gear and the second traction transmission intermediate gear. It is further proposed that the inclination direction of the toothing of the first traction transmission gear stage can be preferably selected such that the axial forces of the gears of the first traction transmission gear stage and the gears of the second traction transmission gear stage act on the traction transmission intermediate shaft in opposite axial directions, i.e. these axial forces at least partially cancel each other out.
[0031] It is further proposed that, as is also the case with the traction transmission output shaft, a fixed-floating bearing can be used to support the traction transmission intermediate shaft, and additionally, the traction transmission drive shaft can also be supported using such a fixed-floating bearing, wherein in particular the floating bearing of the bearing of the traction transmission drive shaft can also be considered as a bearing for another shaft, such as the output shaft of the drive motor, preferably the rotor shaft.
[0032] Furthermore, depending on the planned forward driving direction and the resulting direction of rotation of the traction transmission drive shaft, a particular geometric arrangement of the transmission shafts (traction transmission drive shaft, traction transmission intermediate shaft and traction transmission output shaft) is given. The space requirements of the motor vehicle in which a certain function, here a drive function, must be provided result in boundary conditions to be maintained for the arrangement of the components. Furthermore, the quality of satisfying the function can depend on the arrangement of the components of the transmission shaft in the predetermined installation space, in the present case, in particular in the past, for which reason two alternatives for the arrangement of the transmission shaft are proposed.
[0033] The first of these alternatives therefore constitutes a preferred embodiment of the invention in which, in a plane with respect to the forward driving direction of the motor vehicle and in the planned installation position of the motor vehicle drive system, the traction transmission drive shaft is arranged before the traction transmission intermediate shaft and, further in this first alternative, the traction transmission output shaft is arranged after the traction transmission intermediate shaft.
[0034] In this embodiment, it is further preferred that, with respect to the forward driving direction, in the direction of viewing from the right, the end side of the traction transmission drive shaft, orthogonally (with respect to the rotation axis of the traction transmission drive shaft), the rotation direction of the transmission shaft for generating the movement of the vehicle in the forward driving direction points in the clockwise direction, whereby the traction transmission countershaft has an opposite rotation direction, and the traction transmission output shaft rotates in the same direction as the traction transmission drive shaft. In particular, with such a design of the invention, a small offset of the gears involved in the transmission of the driving force can be achieved, whereby an efficient and operationally safe transmission of the driving force can be achieved with the vehicle drive system in the intended forward driving direction.
[0035] In a preferred embodiment of the invention, the traction transmission countershaft is arranged geometrically higher than the traction transmission drive shaft in a plane with respect to the forward driving direction and in the planned installation position of the motor vehicle drive system, and further preferably the traction transmission output shaft is arranged lower than the traction transmission countershaft and preferably also lower than the traction transmission drive shaft. In particular, such a design results in a small offset of the gears involved in the transmission of the drive forces, thereby enabling an efficient and operationally safe transmission of these drive forces with the motor vehicle drive system in the planned forward driving direction.
[0036] The second alternative of these alternatives constitutes a further preferred embodiment of the invention, in which, in a plane with respect to the forward driving direction and in the planned installation position of the motor vehicle drive system, the traction transmission drive shaft is arranged behind the traction transmission countershaft and further preferably the traction transmission output shaft is arranged before the traction transmission countershaft.
[0037] In this embodiment (second alternative), it is further preferred that, with respect to the forward driving direction, in the direction of viewing from the left, orthogonally (with respect to the rotational axis of the traction transmission drive shaft) to the end side of the traction transmission drive shaft, the direction of rotation of the transmission shaft for generating a movement of the motor vehicle in the forward driving direction points counterclockwise, whereby the traction transmission countershaft has a direction of rotation in the clockwise direction, and the traction transmission output shaft rotates in the same direction as the traction transmission drive shaft.
[0038] In this embodiment, it is further preferred that, in a plane with respect to the forward driving direction and in the planned installation position of the motor vehicle drive system, the traction transmission countershaft is arranged lower than the traction transmission output shaft, and preferably the traction transmission drive shaft is arranged higher than the traction transmission output shaft, and further preferably the traction transmission drive shaft is arranged higher than the traction transmission countershaft. In particular, such a design of the invention makes it possible to achieve small deflections of the gears involved in the transmission of driving force and low noise generation during power transmission with the traction transmission stage, thereby making it possible to achieve an efficient and operationally safe transmission of driving force with the motor vehicle drive system in the planned forward driving direction.
[0039] In this embodiment, it is further preferred that, in a plane with respect to the forward driving direction and in the planned installation position of the motor vehicle drive system, the traction transmission countershaft is arranged higher than the traction transmission output shaft, and preferably the traction transmission drive shaft is arranged higher than the traction transmission output shaft, and further preferably the traction transmission drive shaft is arranged lower than the traction transmission countershaft. In particular, such a design of the invention makes it possible to achieve a small offset of the gears involved in the transmission of the driving force and a low center of gravity for the motor vehicle drive system, thereby making it possible to achieve an efficient and operationally safe transmission of the driving force with the motor vehicle drive system in the planned forward driving direction. BRIEF DESCRIPTION OF THE DRAWINGS
[0040] Individual features and embodiments of the invention are explained in more detail below with reference to the accompanying drawings, in which:
[0041] Figure 1 A schematic cross-sectional view of the proposed motor vehicle drive system orthogonal to the traction transmission drive shaft is shown;
[0042] Figure 2 A first longitudinal section parallel to the traction transmission drive shaft shows the proposed motor vehicle drive system;
[0043] Figure 3 A second longitudinal section parallel to the intermediate shaft of the traction transmission shows the proposed motor vehicle drive system;
[0044] Figure 4 shows a highly schematic top view of a motor vehicle comprising the proposed motor vehicle drive system;
[0045] Figure 5a A schematic top view of a motor vehicle drive system showing a first embodiment;
[0046] Figure 5b A schematic side view of a motor vehicle drive system according to a first embodiment is shown in a planned installation position;
[0047] Figure 6a A schematic top view of a motor vehicle drive system showing a second embodiment;
[0048] Figure 6b A schematic side view of a motor vehicle drive system according to a second specific embodiment is shown in a planned installation position;
[0049] Figure 7a A schematic top view of a motor vehicle drive system according to a modified variant of the second embodiment is shown;
[0050] Figure 7bThe schematic side view of the motor vehicle drive system shows this modified variant of the second embodiment in the planned installation position. DETAILED DESCRIPTION
[0051] exist Figure 1 , a cross section through a motor vehicle drive system is shown, namely a section orthogonal to the traction transmission drive shaft 1 at the level of the gear set of the traction transmission. The electromechanical energy converter is implemented as a drive motor (not shown) in such a motor vehicle drive system. From the drive motor, the drive power for driving the motor vehicle can be transmitted via the traction transmission device shown in section to the motor vehicle axle drive device, in particular the traction transmission output shaft 2 and the traction transmission output gear 3. The traction transmission drive shaft 1 and the traction transmission output shaft 2 of the traction transmission device are rotatably supported in a traction transmission housing device (not shown). The traction transmission drive shaft 1 is connected to a drive motor, in particular the rotor shaft of such a motor, by means of a shaft-hub connection in a rotationally fixed manner.
[0052] Furthermore, the traction transmission arrangement has a traction transmission countershaft 4, which is also rotatably mounted in a traction transmission housing arrangement. The transmission shafts of the traction transmission arrangement are each arranged axially parallel to one another and radially spaced apart from one another and are shown in the present case in the intended installation position in the motor vehicle. Furthermore, the intended forward driving direction 5 is shown with respect to this installation situation. A traction transmission drive gear 19 is arranged on the traction transmission drive shaft 1 and is in meshing engagement with the first traction transmission intermediate gear 6. The traction transmission drive gear 19 is arranged on the traction transmission drive shaft 1. Figure 1 , since the traction transmission drive gear is located behind the traction transmission drive shaft fixed bearing 7. Further arranged on the traction transmission intermediate shaft 4 is a second traction transmission intermediate gear 20 which is in meshing engagement with the traction transmission output gear 3 which is arranged on the traction transmission output shaft 2.
[0053] The three traction transmission shafts shown (traction transmission drive shaft 1, traction transmission intermediate shaft 4, traction transmission output shaft 2) are each supported in a traction transmission housing arrangement by means of fixed-floating bearings and are each connected to the transmission shafts in which they are located so as to be rotationally fixed. Such bearings of the type described are known from the prior art for supporting transmission shafts and have at least one fixed bearing for absorbing axial forces. In the proposed motor vehicle drive system, at least two of these fixed bearings are arranged in a traction transmission cover, which together with the traction transmission housing forms a traction transmission housing arrangement or a component of a traction transmission housing arrangement.
[0054] exist Figure 2 A longitudinal section of a motor vehicle drive system is shown in FIG. Figure 1 Section A in FIG. The drive power is provided by a drive motor 15 which is accommodated in a traction transmission housing arrangement 13 , 14 , wherein the traction transmission housing arrangement is only partially shown.
[0055] The output shaft of the drive motor 15 is directly connected to the traction transmission drive shaft 1 in a rotationally fixed manner via a shaft-hub connection 16. The traction transmission drive shaft 1 is rotatably supported in the traction transmission housing arrangement 13, 14. A traction transmission drive shaft fixed bearing 7 is provided in the traction transmission cover 14, which receives the axial forces occurring on the traction transmission drive shaft 1. Furthermore, the traction transmission drive shaft 1 is supported in the traction transmission housing 13 via a traction transmission drive shaft floating bearing 10. Structurally, the traction transmission drive shaft floating bearing 10 is implemented as a common bearing for the drive motor 15 and the traction transmission drive shaft 1, wherein the drive shaft of the drive motor 15 and the traction transmission drive shaft 1 are centered via the traction transmission drive shaft centering fit 21, so that a support including three bearings can be used for the support of the two shafts, and thus improved efficiency can be achieved compared to separate supports of the two shafts each including two rolling bearings.
[0056] The traction transmission drive gear 19 arranged on the traction transmission drive shaft 1 meshes with a first traction transmission intermediate gear for transmitting drive power, which is not shown in this sectional view. The traction transmission housing arrangement 13, 14 is connected to the vehicle structure (not shown) via an assembly bearing 17 and is thus positioned in the vehicle.
[0057] By not being in the illustrated section A and therefore in Figure 2The traction transmission intermediate shaft (not shown) transmits the driving power from the traction transmission drive shaft 1 to the traction transmission output shaft 2. The traction transmission output shaft 2 is provided with a traction transmission output gear 3, which is designed as a final drive gear and transmits the driving power to the axle differential 18. The traction transmission output shaft 18 is rotatably supported in the traction transmission housing arrangement 13, 14 via a fixed-floating bearing. The fixed bearing device 8 of the traction transmission output shaft 2 is received in the traction transmission cover 14 and has a traction transmission output shaft radial bearing 8a and a traction transmission output shaft axial bearing 8b. The traction transmission output shaft axial bearing 8b is radially free relative to the traction transmission cover 14, so that it does not transmit radial forces between the traction transmission output shaft 2 and the traction transmission cover. Furthermore, the traction transmission output shaft axial bearing 8b is designed as a four-point bearing and has a common outer ring with the traction transmission output shaft radial bearing 8a, and the traction transmission output shaft radial bearing is designed as a roller bearing. The traction transmission output shaft floating bearing 11 is received in the traction transmission housing and is designed as a roller bearing. When the motor vehicle is driven in the forward driving direction 5 , favorable force relations occur on the traction transmission shafts 1 , 2 , 4 due to the helical teeth, so that efficient operation of the motor vehicle drive system is possible.
[0058] exist Figure 3 Another longitudinal section through a motor vehicle drive system is shown in FIG. 1 , wherein the longitudinal section is formed in section B (see Figure 1 ). The motor vehicle drive system is connected to the motor vehicle structure (not shown) via an assembly bearing 17 and is designed to drive the motor vehicle in the forward driving direction 5 and in the opposite direction (rearward). The drive motor 15 is output via a traction transmission intermediate shaft 4, which is arranged between the traction transmission drive shaft 1 and the traction transmission output shaft 2 for power transmission of the drive motor 15. In order to transmit the driving power by means of the traction transmission intermediate shaft 4, the traction transmission intermediate shaft has a first traction transmission intermediate gear 6 and a second traction transmission intermediate gear 20, wherein the first traction transmission intermediate gear 6 is in meshing engagement with the traction transmission drive gear 19, and the second traction transmission intermediate gear 20 is in meshing engagement with the traction transmission output gear 3 for power transmission.
[0059] The traction transmission countershaft is also supported in the traction transmission housing arrangement 13, 14 with a fixed-floating bearing, and also the traction transmission drive shaft 1 and the traction transmission output shaft 2, and wherein, for the two traction transmission countershafts 4, the fixed bearing is also arranged in the traction transmission cover 14. The traction transmission countershaft fixed bearing 9 and the traction transmission countershaft floating bearing 12 are designed as deep groove ball bearings. The traction transmission countershaft fixed bearing is designed to receive the axial forces on the traction transmission countershaft 4 and is fixed in the traction transmission cover 14 for this purpose. The traction transmission countershaft floating bearing 12 is received in the traction transmission housing 13 in an axially movable manner.
[0060] exist Figure 4 , a highly schematic top view of a motor vehicle is shown, which includes a proposed motor vehicle drive system 24. The motor vehicle drive system 24 can provide drive power to a driven front axle 22, so that the motor vehicle can be driven in the forward driving direction 5 or opposite to this direction, i.e., backwards. The motor vehicle further has a non-driven rear axle 22, so that the motor vehicle shown is designed as a front-wheel drive vehicle.
[0061] exist Figure 5a , a schematic top view of a first embodiment of a motor vehicle drive system is shown. The motor vehicle is driven by a drive motor 15, of which only the rotor or the rotor shaft is shown in the present case. The drive motor 15 has a rotor shaft bearing 26 designed as a floating bearing. Furthermore, a parking lock wheel 25 is arranged on the traction transmission drive shaft 1, in particular in order to enable a mechanical locking of the motor vehicle drive system. The traction transmission drive shaft 1 is connected to the rotor shaft of the drive motor 15 in a rotationally fixed manner by means of a shaft-hub connection, and therefore a traction transmission drive shaft floating bearing is considered as a floating bearing of the support of the traction transmission drive shaft, which is arranged on the rotor shaft of the drive motor.
[0062] In the illustrated view, the direction of rotation for the traction transmission drive gear 19 and thereby the traction transmission drive shaft 1 is shown in the planned forward driving direction 5, the arrow direction 28, wherein the inclination angle of the traction transmission drive gear 19 is selected such that the axial forces generated occur in the arrow direction 27 and are therefore directed toward the traction transmission drive shaft fixed bearing 7. The traction transmission drive gear 19 meshes with the first traction transmission intermediate gear 6 for the transmission of drive power, wherein the direction of rotation occurs in the arrow direction 30 and the axial forces occur in the arrow direction 29, and the traction transmission intermediate shaft 4 therefore has the same direction of rotation (arrow direction 30). The inclination angle of the second traction transmission intermediate gear 20 is selected such that the axial forces generated on the second traction transmission intermediate gear 20 are generated in the arrow direction 31 for the power transmission in the planned forward direction 5, and in contrast, axial forces are generated on the first traction transmission intermediate gear (arrow direction 29), so that these axial forces are at least partially offset on the traction transmission intermediate shaft 4. The traction transmission intermediate shaft 4 is rotatably supported by means of the traction transmission intermediate shaft fixed bearing 9 and the traction transmission intermediate shaft floating bearing 12.
[0063] The second traction transmission countershaft gear 20 meshes with the traction transmission output gear 3 on the traction transmission output shaft 2 for power transmission, wherein, in order to provide the driving power for the planned forward driving direction 5, a rotation direction of the traction transmission output shaft occurs in the direction of arrow 34 and an axial force is generated in the direction of arrow 33. The traction transmission output shaft 2 is supported by means of a traction transmission output shaft fixed bearing device 8 having a traction transmission output shaft radial bearing 8a and a traction transmission output shaft axial bearing 8b and a traction transmission output shaft floating bearing 11.
[0064] exist Figure 6a 1 shows a schematic top view of a second embodiment of a motor vehicle drive system, which differs from the first embodiment in which the drive motor 15 is arranged at the front in the planned forward driving direction 5 ( Figure 5a and 5b ), which is arranged at the rear in the second embodiment. The motor vehicle is further driven by a drive motor 15, of which only the rotor or the rotor shaft is shown in the present case.
[0065] Next, we will mainly discuss the first part of the proposed motor vehicle drive system ( Figure 5a / 5b) and the second implementation mode ( Figure 6a The traction transmission countershaft 4 , which in the first embodiment forms the uppermost transmission shaft with respect to its axis of rotation, in the second embodiment forms the lowermost transmission shaft with respect to the planned installation position, in particular with respect to a flat road surface.
[0066] Furthermore, a grounding ring 35 and a radial shaft sealing ring 36 are provided on the traction transmission intermediate shaft 4, which can also be used in the first embodiment. As explained, the inclination angle of the gears is selected so that the axial forces are directed toward the traction transmission drive shaft fixed bearing 8 during driving in the planned forward driving direction, and the axial forces on the traction transmission intermediate shaft 4 are at least partially offset in this driving mode, i.e. have opposite directions.
[0067] exist Figure 7a and 7b In the figure, the driving system of a motor vehicle is shown. Figure 6a and 6b A variant of the second embodiment shown in FIG. 4. In this variant, the traction transmission intermediate shaft 4 is not the lowest transmission shaft of the traction transmission arrangement, but the traction transmission intermediate shaft is arranged above the traction transmission drive shaft 1 and above the traction transmission output shaft 2, and the traction transmission drive shaft is arranged above the traction transmission output shaft 2 but below the traction transmission intermediate shaft 4. Otherwise, refer essentially to the description of the motor vehicle drive system in Figure 6a and 6b An explanation of the second embodiment shown in FIG. Reference numerals list
[0068] A Traction transmission drive shaft section
[0069] B Traction transmission intermediate shaft section
[0070] 1 Traction transmission drive shaft
[0071] 2 Traction transmission output shaft
[0072] 3 Traction transmission output gear
[0073] 4 Traction transmission intermediate shaft
[0074] 5 Forward driving direction
[0075] 6First traction transmission intermediate gear
[0076] 7 Traction transmission drive shaft fixed bearing
[0077] 8Traction transmission output shaft fixed bearing equipment
[0078] 8a Traction transmission output shaft radial bearing
[0079] 8b traction transmission output shaft axial bearing
[0080] 9Traction transmission intermediate shaft fixed bearing
[0081] 10 Traction transmission drive shaft floating bearing
[0082] 11 Floating bearing of traction transmission output shaft
[0083] 12 Traction transmission intermediate shaft floating bearing
[0084] 13 Traction transmission housing
[0085] 14 Traction transmission cover
[0086] 15. Drive motor
[0087] 16 Shaft-hub connection between 15 and 1
[0088] 17 Assembly bearing
[0089] 18-axle differential
[0090] 19 Traction transmission drive gear
[0091] 20 Second traction transmission intermediate gear
[0092] 21 Traction transmission drive shaft centering matching part
[0093] 22 Driven front axle
[0094] 23 Undriven rear axle
[0095] 24Motor vehicle drive system
[0096] 25 parking lock wheels
[0097] 26 Rotor shaft bearing
[0098] 27 Direction of arrow (axial force from the teeth on the traction gearbox drive shaft when driving in the intended forward direction of travel)
[0099] 28 Direction of arrow (direction of rotation of the traction transmission drive shaft when driving in the intended forward direction of travel)
[0100] 29 Direction of arrow (axial force from the toothing of the first traction transmission intermediate gear on the traction transmission intermediate shaft when driving in the planned forward driving direction)
[0101] 30 / 32 Direction of arrow (direction of rotation of the traction gearbox intermediate shaft when driving in the intended forward direction of travel)
[0102] 31 Direction of arrow (axial force from the toothing on the second traction transmission intermediate gear of the traction transmission intermediate shaft when driving in the planned forward driving direction)
[0103] 33 Direction of arrow (axial force from the toothing on the traction gearbox output shaft when driving in the intended forward direction of travel)
[0104] 34 Direction of arrow (direction of rotation of the traction transmission output shaft when driving in the intended forward direction of travel)
[0105] 35 grounding ring
[0106] 36 radial shaft seal ring
Claims
1. A motor vehicle drive system (24), comprising an electromechanical energy converter as a drive motor (15) and a traction transmission device for transmitting drive power to a motor vehicle axle drive, wherein: The traction transmission device has a traction transmission housing device, wherein a traction transmission drive shaft (1) is rotatably supported in the traction transmission housing device, the traction transmission drive shaft is non-rotatably connected to the drive motor (15) or selectively non-rotatably connectable to the drive motor, and the traction transmission device includes a traction transmission intermediate shaft (4), the traction transmission intermediate shaft is rotatably supported in the traction transmission housing device, and the traction transmission intermediate shaft is axially parallel to the traction transmission drive shaft (1) and is radially spaced relative to the traction transmission drive shaft, and the traction transmission device includes a traction transmission output shaft (2), the traction transmission output shaft is rotatably supported in the traction transmission housing device, and the traction transmission output shaft A traction transmission housing device is provided axially parallel to two other traction transmission shafts (1, 4) and radially spaced relative to the two other traction transmission shafts, wherein a traction transmission drive gear (19) is provided on the traction transmission drive shaft (1), the traction transmission drive gear is in meshing engagement with a first traction transmission intermediate gear (6), the first traction transmission intermediate gear is provided on the traction transmission intermediate shaft (4), and wherein a second traction transmission intermediate gear (20) is provided on the traction transmission intermediate shaft (4), the second traction transmission intermediate gear is in meshing engagement with a traction transmission output gear (3), the traction transmission output gear is provided on the traction transmission output shaft (2), and wherein the traction transmission housing device has a traction transmission housing (13) and a traction transmission cover (14), It is characterized in that The three traction transmission shafts (1, 2, 4) are each supported in the traction transmission housing device by a fixed-floating bearing, and such bearings each have at least one fixed bearing for absorbing axial forces, and at least two of these fixed bearings are arranged in the traction transmission cover (14).
2. The motor vehicle drive system according to claim 1, characterized in that All fixed bearings of each of the traction transmission shafts (1, 2, 4) are arranged in the traction transmission cover (14).
3. A motor vehicle drive system according to any one of the preceding claims, characterized in that The traction transmission drive gear (19) and the first traction transmission intermediate gear (6) form a first traction transmission gear stage, and the end surface overlap of the first traction transmission gear stage is greater than 1.70 and less than 1.90, and the longitudinal overlap of the first traction transmission gear stage is greater than 3.10 and less than 3.
30.
4. A motor vehicle drive system according to any one of the preceding claims, characterized in that The second traction transmission intermediate gear (20) and the traction transmission output gear (3) form a second traction transmission gear stage, and the end surface overlap of the second traction transmission gear stage is greater than 1.40 and less than 1.60, and the longitudinal overlap of the second traction transmission gear stage is greater than 2.40 and less than 2.
60.
5. A motor vehicle drive system according to any one of the preceding claims, characterized in that The first traction transmission intermediate gear (6) comprises first helical teeth with a first inclination angle, and the second traction transmission intermediate gear (20) comprises second helical teeth with a second inclination angle, and the first and second inclination angles point in the same direction, so that axial forces occurring on the two traction transmission intermediate gears (6, 20) during power transmission are at least partially offset.
6. A motor vehicle drive system according to any one of the preceding claims, characterized in that The traction transmission drive shaft (1) is supported in the traction transmission housing device by means of a fixed-floating bearing, the fixed-floating bearing comprising a fixed bearing for receiving axial forces and a floating bearing, the fixed bearing and the floating bearing of the bearing being both constructed as deep groove ball bearings, the fixed bearing being arranged in a traction transmission cover (14), and the drive motor (15) being arranged on or in the traction transmission housing (13).
7. A motor vehicle drive system according to any one of the preceding claims, characterized in that The traction transmission intermediate shaft (4) is supported in the traction transmission housing device by means of a fixed-floating bearing, the fixed-floating bearing comprising a fixed bearing for receiving axial forces and a floating bearing, the fixed bearing and the floating bearing both being designed as deep groove ball bearings, the fixed bearing being arranged in a traction transmission cover (14).
8. A motor vehicle drive system according to any one of the preceding claims, characterized in that The traction transmission output shaft (2) is supported in the traction transmission housing device by means of a fixed-floating bearing, the fixed-floating bearing comprising a fixed bearing for receiving axial forces and a floating bearing, the bearing of the traction transmission output shaft (2) having a first and a second roller bearing, wherein the roller bearings are arranged on different sides of the traction transmission output gear (3) in the axial direction, and the fixed bearing is designed as a deep groove ball bearing or as a four-point bearing and is arranged in the traction transmission cover (14).
9. A motor vehicle comprising at least one motor vehicle drive system (24) according to one of the preceding claims and a forward driving direction (5), the motor vehicle being drivable in the forward driving direction by means of the motor vehicle drive system (24).
10. The motor vehicle according to claim 9, characterized in that With respect to the forward driving direction (5) in a plane and in the planned installation position of the motor vehicle drive system, the traction transmission drive shaft (1) is arranged upstream of the traction transmission countershaft (4) and the traction transmission output shaft (2) is arranged downstream of the traction transmission countershaft (4).
11. The motor vehicle according to claim 9 or 10, characterized in that With respect to the forward driving direction (5) in a plane and in a planned installation position of the motor vehicle drive system (24), the traction transmission intermediate shaft (4) is arranged higher than the traction transmission drive shaft (1), and the traction transmission output shaft (2) is arranged lower than the traction transmission drive shaft (1).
12. The motor vehicle according to claim 9, characterized in that With respect to the forward driving direction (5), in a plane and in the planned installation position of the motor vehicle drive system, the traction transmission drive shaft (1) is arranged behind the traction transmission countershaft (4) and the traction transmission output shaft (2) is arranged in front of the traction transmission countershaft (4).
13. The motor vehicle according to claim 9 or 12, characterized in that With respect to the forward driving direction (5) in a plane and in a planned installation position of the motor vehicle drive system (24), the traction transmission intermediate shaft (4) is arranged lower than the traction transmission output shaft (2), and the traction transmission drive shaft (1) is arranged higher than the traction transmission output shaft (2).
14. The motor vehicle according to claim 9 or 12, characterized in that With respect to the forward driving direction (5) in a plane and in a planned installation position of the motor vehicle drive system (24), the traction transmission intermediate shaft (4) is arranged higher than the traction transmission output shaft (2), and the traction transmission drive shaft (1) is arranged higher than the traction transmission output shaft (2).
15. The motor vehicle according to any one of claims 9 to 14, characterized in that The traction transmission output gear (3) comprises an output helical toothing having an output inclination angle, the output inclination angle being selected such that an axial force of the traction transmission output gear (3) is directed from the traction transmission cover (14) toward the traction transmission housing (13) along the axial direction of the traction transmission output shaft (2) when the motor vehicle is driven in the forward driving direction (5).
Citation Information
Patent Citations
Arrangement of a gearbox and an electric machine
DE102019127242A1