Drive train for a vehicle

Abstract

The invention relates to a drive train for a vehicle (15), wherein the drive train has at least one motor (9), such as an electric motor or an internal combustion engine, the motor (9) being rotationally connected to a first shaft (1) in order to transmit the driving torque, wherein the drive train has a second shaft (2) which is arranged coaxially with respect to the first shaft (1), wherein the drive train has a sliding sleeve (4) which can couple the first shaft (1) and the second shaft (2) and decouple same from each other, wherein the drive train has at least one locking pawl (6) and has a corresponding parking lock wheel (5), characterized in that the locking pawl (6) is pivotable about a pivot axis (S) between the locking position and the release position, and in that the pivot axis (S) is normal to the axis of rotation (A) of the first shaft (1) and second shaft (2).

Description

[0001] Drivetrain for a vehicle

[0002] The invention relates to a drive train for a vehicle, wherein the drive train has at least one motor, such as an electric motor or an internal combustion engine, wherein the motor is rotationally connected to a first shaft for transmitting the drive torque, wherein the drive train has a second shaft arranged coaxially with the first shaft, wherein the drive train has a shift sleeve which, in a first position, decouples the first shaft and the second shaft from one another and, in a second position, couples the first shaft and the second shaft to one another in a rotationally fixed manner, wherein the drive train has at least one pawl and the first shaft and / or the second shaft has a parking lock gear, wherein the pawl can be brought into at least one locking position and at least one release position,wherein in the locked position the pawl locks the parking lock gear against rotation and in the released position the pawl releases the parking lock gear, wherein the pawl is movable between the locked position and the released position by means of the shift sleeve.

[0003] The invention also relates to a motor vehicle, wherein the vehicle has a drive train according to the invention.

[0004] Pawls are often used to prevent unintentional movement, such as rolling away, when the vehicle is stationary. To do this, the pawl locks a parking lock gear against rotation in a locked position, whereby the parking lock gear is rotationally connected to the vehicle's wheels, at least in the locked position. Such pawls must sometimes counteract large forces, particularly when they are locked before the vehicle has come to a complete stop. Therefore, they must be sufficiently solid and robust. In the current state of the art, such pawls are lowered linearly onto the parking lock gear or pivoted about an axis parallel to the axis of rotation of the first shaft. Pivoting about an axis parallel to the axis of rotation requires separate actuation mechanisms, making the design complex.

[0005] DE 10 2021 204 923 A1 discloses a locking mechanism in which the pawl is pivoted about an axis parallel to the rotational axis of the first shaft. This is achieved by displacing a shift sleeve axially relative to the rotational axis, which pushes the pawl toward the parking lock gear. Such an embodiment requires a compact design that requires only one switching part, namely the shift sleeve, to connect the shafts to one another and to actuate the pawl. However, this embodiment results in a linear movement of the pawl in the longitudinal section between the release position and the locked position. In order for the entire pawl to fit under the shift sleeve, it must be made thin. This leads to canting. Furthermore, the small contact surface exerts high pressure on the pawl.In addition, due to the limited space, it is difficult to arrange a spring that biases the pawl into the release position.

[0006] The object of the invention is to provide a drive train which has a low risk of jamming of the pawl and is nevertheless as robust, safe and easy to operate as possible.

[0007] This object is achieved according to the invention in that the locking pawl can be pivoted about a pivot axis between the locking position and the release position, and in that the pivot axis is normal to the axis of rotation of the first shaft and second shaft.

[0008] This arrangement reduces the risk of jamming. Since the movement is not linear but pivotal, the pivoting attachment along the rotational axis of the parking lock gear can be removed. This allows the space between the shift sleeve and the parking lock gear to be better utilized by the part of the pawl connecting to the parking lock gear, making it larger. This also allows the pawl to be constructed more robustly, increasing its service life.

[0009] Furthermore, the forces are more effectively utilized. During a linear movement, as in the above-mentioned embodiment, the shift sleeve presses on the pawl with a force parallel to the rotational axis to displace it radially inward. This force does not assist the pawl in its movement. In the embodiment according to the invention, the force of the shift sleeve is more effectively utilized, since the pivoting around the pivot axis creates both a radial component and a component parallel to the rotational axis.

[0010] The first shaft is rotatably connected to the engine; generally, it is the input shaft through which the engine feeds drive torque into the rest of the drivetrain. The engine may not be continuously rotatably connected to the first shaft, for example, if the engine is connected to the first shaft via a manual transmission comprising clutch devices. It is important that the first shaft is designed to transport the engine's drive torque along the drivetrain. The second shaft is usually an output shaft, i.e. a shaft that directs the drive torque towards at least one wheel. However, the second shaft can also be another shaft in the drivetrain that is involved in transmitting drive torque. For example, it can be the input shaft of a second engine.

[0011] The shift sleeve is a component, preferably sleeve-shaped or sleeve-segment-shaped, that can be moved along the rotational axis. It can thus assume various positions and connect the two shafts in a rotationally fixed manner or decouple them from each other in a rotationally movable manner. Since the first shaft is coaxial with the second shaft, the rotational axis is the same for both shafts. The drive train preferably has a motion actuator that moves the shift sleeve at least parallel to the rotational axis.

[0012] For the purposes of the invention, "rotatably connected," "rotatably connected," or "coupled" refers to a rotationally fixed connection between two elements or components. Thus, rotational movement and torque are transmitted between the elements. Accordingly, "locking against rotation" refers to the pawl being non-rotatably connected to the parking lock gear, thus preventing further rotation of the parking lock gear relative to the pawl. This is typically achieved by the pawl engaging the parking lock gear.

[0013] Decoupling two elements, on the other hand, means that the two elements are not connected to each other in a rotationally fixed manner by the shift sleeve. They can therefore rotate relative to each other. Accordingly, releasing means that the pawl does not inhibit the rotation of the parking lock gear. This is usually achieved by disengaging the pawl from the parking lock gear.

[0014] The parking lock gear is a gear that is preferably arranged on the first and / or second shaft and is preferably designed as a spur gear. It is preferably designed to form a positive and / or frictional connection with the pawl in the locked position. It is rotationally connected to the first and / or second shaft at least when the pawl is in the locked position. However, it is generally non-rotatably connected to the first and / or second shaft throughout.

[0015] "Perpendicular to the rotation axis" means that the pivot axis lies in a normal plane of the rotation axis. Preferably, the pivot axis is spaced from the rotation axis. Preferably, at least one pawl has an extension designed as a stop for the release position. "Stop for the release position" means that the extension rests against a housing part or another element in the release position, thus inhibiting further movement of the pawl.

[0016] Preferably, the pawl has a locking portion for connecting the pawl to the parking lock gear during the locking position.

[0017] Preferably, at least one pawl is attached to a housing or a part rigidly connected to the housing. This prevents rotation of the shaft to which the pawl is rigidly connected in the locked position.

[0018] Preferably, the pawl has a fastening portion for fastening to a housing or a part connected to the housing.

[0019] Preferably, a contact line along which the locking portion connects to the parking lock gear in the locked position is substantially perpendicular to the rotation axis. This ensures that the contact force at the contact point is optimally utilized to rotate the pawl about its axis.

[0020] It is preferably provided that in the locking position the locking portion of at least one pawl has approximately the same radial distance from the axis of rotation as its pivot axis.

[0021] It can also be advantageous for the locking portion of at least one pawl to be located at a smaller radial distance from the rotational axis than its pivot axis in the locked position. This requires the contact point between the parking lock gear and the pawl to be approximately on a horizontal line. This allows the contact force at the contact point to be optimally utilized for rotating the pawl around its axis.

[0022] It is preferably provided that the pawl is in the release position in the first and second positions of the shift sleeve and in the locked position in a third position of the shift sleeve. In this way, the shift sleeve can assume different functions depending on the current requirement and connect the shafts to one another without activating the parking lock. The release position in the first and second positions can be designed differently. For example, the pawl can be pivoted somewhat closer in the direction of the locked position in the second position than in the first position. What is important, however, is that both positions are a release position, i.e. that the pawl does not lock the parking lock gear. Furthermore, it is advantageous if the first shaft and the second shaft are coupled to one another in a rotationally fixed manner by the shift sleeve in the third position of the shift sleeve.In this way, the resistance of the engine can be used in addition to preventing the vehicle from rolling away and reducing the force acting on the pawl.

[0023] It is advantageous to provide at least two, preferably four, pawls that engage the same parking lock gear in the locked position and are preferably evenly arranged around the circumference of the parking lock gear. This allows several pawls to be engaged simultaneously with the same shift sleeve. Furthermore, the force is distributed across several pawls, thus reducing the load on the individual pawls.

[0024] It can be provided that the first shaft has a first coupling section and the second shaft has a second coupling section, wherein the shift sleeve is rotationally fixedly coupled to the first coupling section and the second coupling section in the second position and is decoupled from at least one of the two coupling sections in the first position. In particular, the first coupling section is preferably rotationally fixedly connected to the first drive shaft and the second coupling section is rotationally fixedly connected to the second drive shaft.

[0025] The first and / or second coupling section can be integrally connected to the respective shaft and / or formed as separate components, in particular as a coupling gear. The rotationally fixed coupling is preferably achieved via a positive connection between the coupling section and the shift sleeve.

[0026] It is particularly advantageous if at least one of the coupling sections comprises a coupling gear into which the shift sleeve engages. In this case, the shift sleeve can have a toothing that engages the coupling gear. It can also be provided that the first and second coupling sections each have at least one coupling gear, and the shift sleeve has a toothing that can be brought into engagement with both coupling gears. This results in a particularly simple design of the shift sleeve.

[0027] Preferably, the shift sleeve comprises at least one guide section configured to pivot the pawl between the locking position and the release position upon displacement of the shift sleeve along the rotational axis. This guide section and / or the pawl preferably comprise a guide contour for guiding the pawl from the release position to the locking position. It may be provided that the guide section is in contact with the pawl in every position; it may also be provided that the guide section is spaced from the pawl at least in the first position.

[0028] It is particularly advantageous if at least one pawl has several teeth that engage with the toothing of the parking lock gear in the locked position. The inventive arrangement of the pivot axis perpendicular to the rotation axis allows a pawl to connect to a larger portion of the circumference of the parking lock gear without having to significantly increase the pivot angle between the release position and the locked position. This enables a better connection and force dissipation.

[0029] It is advantageous if the pawl is preloaded into the release position by at least one spring element. This ensures automatic return to the release position when the shift sleeve releases the pawl.

[0030] In order to make the embodiment even more robust, it can be provided that at least one pawl has at least two bearings and that preferably at least one spring element, which preloads the pawl into the release position, is arranged between the bearings.

[0031] Preferably, at least one stop is provided which limits the movement of the shift sleeve in the direction from the second and / or third position to the first position. The stop preferably limits the movement of the shift sleeve such that it cannot be pushed beyond the first position. This prevents the shift sleeve 4 from overshooting the neutral position if no end stop is otherwise present along the actuation path. This prevents transmission damage. Furthermore, this can be used to detect the end position for the actuator if the adjustment path is determined via incremental sensors. The actuator is, for example, an electric motor that moves the shift sleeve.

[0032] The invention is explained in more detail below with reference to the non-limiting embodiment shown in the figures. They show:

[0033] Fig. 1a is a schematic representation of a drive system according to the invention in a first embodiment in a motor vehicle according to the invention;

[0034] Fig. lb shows a part of a longitudinal section of the drive system from Fig. la with the shift sleeve in a first position;

[0035] Fig. lc shows the part of the longitudinal section according to Fig. lb with the shift sleeve in a second position;

[0036] REPLACEMENT LEAF (RULE 26) Fig. Id the part of the longitudinal section according to Fig. lb with the shift sleeve in a third position;

[0037] Fig. 2 shows selected parts of a longitudinal section of a drive system according to the invention of a motor vehicle according to the invention in a second embodiment with the shift sleeve in all three positions in a superimposed representation;

[0038] Fig. 3 shows a part of a longitudinal section of a shift sleeve of the second embodiment;

[0039] Fig. 4 is a side view of part of a third embodiment of a drive system according to the invention.

[0040] The first embodiment according to the invention from Figures 1a - 1d has an engine 9 which provides the drive torque and is rotationally connected to a first shaft 1 - optionally with the interposition of further components such as a manual transmission 12 or a fixed gear ratio. This first shaft 1 can be rotationally connected to a second shaft 2 via a shift sleeve 4. The first shaft 1 and the second shaft 2 are arranged coaxially and thus have the same axis of rotation A. The first shaft 1 provides drive torque of the engine. The second shaft 2 is part of a differential 13 and is connected via this to two wheels 14. This structure of a drive train according to the invention is shown schematically in Fig. 1a as part of a vehicle 15 according to the invention.

[0041] 1b - 1d show in more detail the part of the first shaft 1 and second shaft 2 which can be rotatably connected via the shift sleeve 4. The first shaft 1 has a recess at its end in which the second shaft 2 is partially arranged. At their ends, the first shaft 1 has a first coupling section 1a and the second shaft 2 has a second coupling section 2a, which are arranged adjacent to one another in the axial direction. The first coupling section 1a has a coupling gear 3 which is connected to the first shaft 1 in a rotationally fixed manner. The second coupling section 2a has external teeth, similar to the coupling gear 3, and thus assumes the function of a coupling gear.

[0042] A shift sleeve 4 is arranged radially outside the coupling wheel 3, which is connected to the coupling wheel 3 in a rotationally fixed manner, but is movable in the axial direction relative to the rotation axis A.

[0043] At the end of the shift sleeve 4 facing away from the second shaft 2, a retaining ring 15 is provided on the coupling gear 3. This serves as the end stop for the shift sleeve 4 in the neutral position. The end stop can also be provided in other designs and does not necessarily have to be a retaining ring. The axial position of the shift sleeve 4 is held in defined positions by a locking element 8. In this embodiment, the locking element 8 has a ball or pin pre-tensioned in the direction of the shift sleeve 4 by a spring. When the shift sleeve 4 moves, the contoured surface of the shift sleeve 4 facing the locking element 8 moves along the locking element 8. The locking element 8 keeps the shift sleeve 4 in defined positions, whereby the first, second and third positions can be easily defined.The contour of the surface of the shift sleeve 4 is not shown in Figures 1b - 1d for the sake of clarity, but can be designed as in the embodiment according to Fig. 2 or similarly.

[0044] A parking lock gear 5 is arranged along the rotational axis A, directly adjacent to the second coupling section 2a, and is connected in a rotationally fixed manner to the second shaft 2. Several pawls 6 are arranged radially outside the parking lock gear 5, whereby in the longitudinal section according to Figure 1b, only one pawl 6 is visible, which can be pivoted about its respective pivot axis S, whereby the pivot axis S is arranged in a normal plane of the rotational axis A and at a distance from the rotational axis A.

[0045] The pawl 6 has a locking portion 6a, which, in the locked position, is operatively connected to the parking lock gear 5, thus establishing a rotationally fixed connection between the pawl 6 and the parking lock gear 5. This position is shown in Fig. 1d. The pawl 6 also has a fastening portion 6b for attachment to a housing 7 or a part connected to the housing. By means of this fastening portion 6b, the pawl 6 is pivotally mounted on the housing 7.

[0046] The locking pawl 6 has an extension 6c, which is designed as a stop and is positioned at an angle to the locking portion 6a. In the release position, it rests against the housing, as shown in Figures 1b and 1c.

[0047] The locking section 6a has a connecting surface facing the parking lock gear 5, which is curved according to the circumference of the parking lock gear 5 and on which several teeth are arranged. These teeth engage with the toothing of the parking lock gear 5 in the locked position.

[0048] The pawl 6 is pre-tensioned into the release position by a spring element 11.

[0049] In this embodiment, the pivot axis S has a radial distance E from the rotation axis A, which in the locked position is greater than the radial distance e of the locking portion 6a. The shift sleeve 4 has, in the axial direction, at its end facing the pawl 6, a guide portion 4b which has a guide contour 4c in order to pivot and guide the pawl 6 between the release position and the locked position.

[0050] On the side of the shift sleeve 4 facing the second shaft 2, the shift sleeve 4 has an internal toothing 4d, which meshes with the spur gear of the second shaft 2 in the second position (see Fig. 1b) and the third position (see Fig. 1d). Thus, in these positions, a rotationally fixed connection between the first and second shafts 1, 2 is achieved.

[0051] Fig. 2 shows a variant very similar to the first embodiment, so only the most significant differences will be discussed here. Parts with equivalent functions have the same reference numerals.

[0052] This embodiment shows how the shift sleeve 4 is displaced in the axial direction. Therefore, only the most essential parts are shown here. The shift sleeve 4 and pawl 6 are shown in all three positions, with the first position represented by solid lines and the second and third positions represented by dashed lines. The displacement is achieved via a linear actuator 10, which is designed as an electromagnetic lifting drive.

[0053] Fig. 3 shows the shift sleeve 4 in detail. On the side facing the coupling gear 3, the shift sleeve 4 has a contoured surface with a plurality of notches 4a. The locking element 8 can engage in these notches 4a, thus fixing the position of the shift sleeve 4. The partial surfaces between the notches are chamfered and designed to guide the shift sleeve 4 into one of the positions, i.e., the first, second, or third position.

[0054] Fig. 4 shows a third variant very similar to the first and second embodiments; therefore, only the most significant differences will be discussed here. Parts with equivalent functions have the same reference numerals.

[0055] Fig. 4 shows only a portion of the first and second shafts 1, 2, the shift sleeve 4, and the pawls 6. For clarity, the pawls 6 are shown in the locked position, although the shift sleeve is shown in the first position. This position combination is not achieved during operation.

[0056] Four pawls 6, designed as in the first embodiment, are evenly distributed around the circumference of the parking lock gear 5. Each pawl 6 has two bearings 6d, which allow the pawls 6 to be particularly well connected to the housing. A spring element 11 is arranged between each of the two bearings 6d, which is supported on the housing via two arms 11a.

[0057] Each locking section 6a of each pawl 6 has three teeth that engage with the toothing of the parking lock gear 5 in the locked position. For this purpose, the locking section 6a is adapted to the circumferential contour of the parking lock gear 5.

Claims

P A T E N T A N S P R Ü C H E 1. A drive train for a vehicle (15), wherein the drive train comprises at least one motor (9), such as an electric motor or an internal combustion engine, wherein the motor (9) is rotationally connected to a first shaft (1) for transmitting the drive torque, wherein the drive train comprises a second shaft (2) arranged coaxially with the first shaft (1), wherein the drive train comprises a shift sleeve (4) which, in a first position, decouples the first shaft (1) and the second shaft (2) from one another and, in a second position, couples the first shaft (1) and the second shaft (2) to one another in a rotationally fixed manner, wherein the drive train comprises at least one pawl (6) and the first shaft (1) and / or the second shaft (2) comprises a parking lock gear (5), wherein the pawl (6) can be brought into at least one locking position and at least one release position,wherein in the locked position, the pawl (6) locks the parking lock gear (5) against rotation and in the released position, the pawl (6) releases the parking lock gear (5), wherein the pawl (6) is movable between the locked position and the released position by means of the shift sleeve (4), characterized in that the pawl (6) is pivotable about a pivot axis (S) between the locked position and the released position, and that the pivot axis (S) is normal to the axis of rotation (A) of the first shaft (1) and second shaft (2).

2. Drive train according to claim 1, characterized in that the pawl (6) is in the release position in the first position and the second position of the shift sleeve (4) and is in the locking position in a third position of the shift sleeve (4).

3. Drive train according to claim 2, characterized in that the first shaft (1) and the second shaft (2) are coupled to one another in a rotationally fixed manner by the shift sleeve (4) in the third position of the shift sleeve (4).

4. Drive train according to one of claims 1 to 3, characterized in that at least two, preferably four pawls (6) are provided, which engage in the same parking lock gear (5) in the locking position and are preferably arranged uniformly around the circumference of the parking lock gear (5).

5. Drive train according to one of claims 1 to 4, characterized in that the first shaft (1) has a first coupling section (la) and the second shaft (2) has a second coupling section (2a), wherein the shift sleeve (4) is coupled in a rotationally fixed manner to the first coupling section (la) and the second coupling section (2a) in the second position and is decoupled from at least one of the two coupling sections (la, 2a) in the first position.

6. Drive train according to claim 5, characterized in that at least one of the coupling sections (la) comprises a coupling wheel (3) into which the shift sleeve (4) engages.

7. Drive train according to one of claims 1 to 6, characterized in that the shift sleeve (4) has at least one guide section (4b) which is designed to pivot the pawl (6) between the locking position and the release position when the shift sleeve (4) is displaced along the axis of rotation (A).

8. Drive train according to one of claims 1 to 7, characterized in that at least one pawl (6) has a plurality of teeth which, in the locking position, engage in a toothing of the parking lock gear (5).

9. Drive train according to one of claims 1 to 9, characterized in that at least one pawl (6) has at least two bearings (6d) and that preferably at least one spring element (11) which pretensions the pawl (6) into the release position is arranged between the bearings (6d).

10. Motor vehicle (15), wherein the vehicle has a drive train according to one of the preceding claims.

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