Parking lock device for a gearbox with a parking lock gear

Abstract

The invention relates to a parking lock device (1) for a transmission of a motor vehicle, comprising a locking element (3) which is pivotably mounted about a rotational axis (2), the locking element (3) comprising a locking lever (4) and an unlocking lever (5) connected in one piece therewith, an unlocking unit (6), an actuating element (7) for activating or deactivating the parking lock device (1), and a return spring (9), wherein the locking element (3) can be actuated by the unlocking unit (6) in such a way that the locking element (3) pivots about the rotational axis (2) from a locking position into an unlocking position, wherein the return spring (9) is operatively connected to the locking element (3) in such a way that the locking element (3) is pressed about the rotational axis (2) into the unlocking position, wherein a locking section (11) of the locking lever (4) in the locking position engages in an at least partially circumferential locking groove (12) of the actuating element (7). intervenes,to positively lock the actuating element (7) in an axial position, and wherein a balancing mass (10) is arranged on the locking element (3) on a side of the rotational axis (2) opposite to the unlocking lever (5) and / or the locking lever (4).

Description

[0001] The invention relates to a parking lock device for a transmission of a motor vehicle with a parking lock gear, comprising a pawl which is designed to cooperate with a toothing of a parking lock gear in order to release a rotation of the parking lock gear in an unlocking position and to engage in the toothing of the parking lock gear in a locking position and to lock a rotation of the parking lock gear.

[0002] When actuated by a driver of the motor vehicle, parking lock devices engage with the parking lock gear with the pawl in order to block a drive shaft or output shaft of the motor vehicle that is operatively connected to the parking lock gear against rotation and thus prevent the motor vehicle from rolling away.

[0003] Parking lock devices are known from the prior art in which a spring-loaded, eccentrically mounted lever or pawl is provided for locking the parking lock actuating rod. The lever can be unlocked both by means of a solenoid and redundantly by means of a hydraulic piston. Furthermore, locking units are known that are designed to lock the lever or pawl in its engaged and / or disengaged position.

[0004] For example, DE 10 2021 116 952 A1 discloses a parking lock for a motor vehicle transmission, comprising a pawl rotatable about a rotational axis with a locking tooth configured to lock a parking lock gear in a locked position and to release the parking lock gear in an unlocked position. Furthermore, a locking element is provided, with which the pawl can be moved into the locked position. Furthermore, a guide rod is provided, on which the locking element is arranged. An actuator has an actuating member, by means of which the guide rod is linearly displaceable. The actuating member and the guide rod form a pivot joint.

[0005] Other relevant actuators are known from CN 1 12 212 004 A, DE 10 2022 000 597 A1, DE 10 2022 204 691 A1 and EP 1 679 456 A1.

[0006] The object of the present invention is to provide a parking lock device that is resistant to impact forces. This object is achieved by the subject matter of patent claim 1. Preferred embodiments can be found in the dependent claims.

[0007] A parking lock device according to the invention for a transmission of a motor vehicle comprises a locking element which is pivotably mounted about a rotational axis, the locking element comprising a locking lever and an unlocking lever connected in one piece thereto, an unlocking unit, an actuating element for activating or deactivating the parking lock device, and a return spring, wherein the locking element can be actuated by the unlocking unit in such a way that the locking element pivots about the rotational axis from a locking position into an unlocking position, wherein the return spring is operatively connected to the locking element in such a way that the locking element is pressed about the rotational axis into the locking position, wherein a locking portion of the locking lever engages in an at least partially circumferential locking groove of the actuating element in the locking position in order to positively lock the actuating element in an axial position,and wherein a balancing mass is arranged on the locking element on a side of the rotational axis opposite to the unlocking lever and / or the locking lever.

[0008] The locking element is preferably made from sheet metal and can be given the desired shape by punching and optionally forming. The locking element is arranged in the form of a pawl or the like so that it can rotate about the axis of rotation. The possible rotation range of the locking element is defined and limited by two end stops, on the one hand the locked position of the locking element and on the other hand, or in the opposite direction of rotation, the unlocked position of the locking element. The locking lever is designed to form a positive connection with the actuating element in the locked position of the locking element, so that the actuating element is prevented from longitudinal displacement. In the locked position, the locking lever preferably only comes into contact with the actuating element with the locking section, which is designed, for example, as a locking tooth.In the unlocked position, the locking lever does not come into contact with the actuating element, so that the actuating element can be freely adjusted in its axial position to activate or deactivate the parking lock device.

[0009] The unlocking unit can be designed in different ways. In particular, the unlocking unit can comprise one or more actuating elements that can be actuated in different ways. For example, the unlocking unit can be or comprise an electromagnetically switchable unlocking unit that is operatively connected to the locking element in such a way that the locking element is pressed about the axis of rotation into the unlocked position. The unlocking unit is in particular a lifting magnet. A lifting magnet is an electromagnetic component that serves to attract and hold ferromagnetic objects by applying an electrical voltage when current flows through its coil. When the lifting magnet is actuated, the locking element is actuated in such a way that the locking lever is moved out of the locking groove until the locking element is in the unlocked position. The unlocked position is held as long as the lifting magnet is supplied with electrical current.is activated. If the current through the solenoid coil is interrupted, the magnetic field disappears and the actuating force decreases. This pushes the locking element, assisted by the return spring, toward the locking position. When the locking portion of the locking lever is aligned with the locking groove, the locking portion engages the locking groove, thereby axially securing or locking the actuating element.

[0010] Alternatively or additionally, the unlocking unit is or comprises a hydraulically actuated actuating element that is operatively connected to the locking element in such a way that the locking element is pressed about the rotational axis into the unlocked position. For example, the hydraulic actuating element is designed as an additional unlocking piston of the parking lock device. The unlocking piston is preferably arranged in the region of the unlocking lever of the locking element and, when actuated, acts on the unlocking lever. The unlocking piston or the plunger of the solenoid have the same function, namely the actuation of the locking element, so that the locking element is actuated or moved from the locked position to the unlocked position.

[0011] In this sense, the unlocking unit preferably comprises a lifting magnet and / or a hydraulically actuated actuating element, wherein the unlocking unit is operatively connected to the locking element in such a way that the locking element is pressed about the rotation axis into the unlocked position.

[0012] The return spring is designed to return the locking element to the locked position. The return spring is supported on the housing of the parking lock device. The return spring rests on the housing of the parking lock device and on the release lever of the locking element. The return spring can be a conventional coil spring, which, when compressed, particularly when the locking element is rotated into the unlocked position, exerts an axially acting return force toward the locking element's locked position. Other types of return springs are also conceivable, enabling reliable actuation of the locking element.

[0013] The locking groove is an at least partially circumferential recess on the outer circumference of the actuating element. The actuating element can be rod-shaped or sleeve-shaped and is axially guided and radially positioned in a housing of the parking lock device.

[0014] The locking position is to be understood as the normal position of the device, since the return spring automatically pushes the locking element into the locking position. The locking portion of the locking lever can be actively moved out of the locking groove and pushed into the unlocked position, and held if necessary, simply by actuating the locking element, at least by means of the unlocking unit.

[0015] The balancing mass is an additional mass of the locking element, which is arranged in such a way that a mass balancing section or lever is realized for balancing the mass of the locking lever and the unlocking lever. The balancing mass is preferably arranged on the locking element in such a way that it extends essentially perpendicular to a direction of action of impact forces acting on the parking lock device. The balancing mass is a type of additional "arm" on the locking element. Depending on the arrangement and design of the balancing mass, the return spring can also be effectively arranged on the balancing mass in order to support or carry out the return of the locking element to the locked position. The point of application for the return spring can be arranged depending on the available installation space and / or an assembly or disassembly option.In this sense, the return spring can act either directly on the release lever, directly on the locking lever or directly on the balancing mass.

[0016] According to one embodiment, the mass balancing is completely balanced, so that regardless of the magnitude of the impact force, hereinafter also referred to as "impact," no unwanted rotation of the locking element about the rotation axis results. Such unwanted rotation could result in the unintentional activation of the parking lock.

[0017] According to another embodiment, the mass of the locking lever and the unlocking lever is balanced by the compensating mass at least to the extent that the required or desired impact safety is met without having to modify the design of the return spring, i.e., make it larger or slimmer. In this case, the additional mass is reduced to a necessary minimum, which has a positive effect on the overall mass, the additional installation space required, and the material costs of the parking lock device.

[0018] The balancing mass does not necessarily have to be arranged directly opposite the original center of gravity of the lever without any balancing mass. This would require more material for the necessary mass balance around the pivot point, but this can be accepted for reasons of installation space. Rather, the desired protection against impacts is already achieved if the balancing mass extends essentially perpendicular to the direction of action of impact forces. Since impact forces generally act vertically, it is advantageous if the balancing mass extends essentially in a horizontal direction. In this sense, the longitudinal extension of a bolt that forms the balancing mass runs perpendicular to the direction of action of the impact forces, preferably in a horizontal direction. A balancing mass is therefore expressly not to be understood as an existing section, arm or area of ​​the locking element that is intended or required for the design of the locking element anyway.Rather, the leveling compound is an additional component section that is arranged at a specific and predetermined location on the barrier element. The optimal location for the leveling compound is determined through tests, experiments, and / or simulations.

[0019] It can be advantageous not to position the leveling mass exactly opposite the release lever and / or the locking lever. Particularly with stamped components, alternative arrangement of the leveling mass can achieve better utilization of a circuit board or sheet from which the locking element is punched. This reduces waste and allows more components to be manufactured from a single circuit board. With this in mind, the shape and geometry of the leveling mass can also be adapted accordingly. In this sense, the leveling mass is preferably designed as a single piece with the locking lever and the release lever. In other words, the leveling mass can be manufactured as a single piece with the locking lever and the release lever during the production of the locking element, e.g., in a stamping process, using the tool.

[0020] Alternatively, the leveling compound is attached to the locking element. In other words, the leveling compound can also be an additional part that is fixed to the locking element, for example, by joining or another fastening step. The additional part can be made of a different material than the rest of the locking element and / or manufactured using a different process. Thus, the additional part and the locking element can be made of different materials with different material properties.

[0021] The compensating mass can be designed to be tolerant, eliminating the need for a balancing process or a precise outer contour. The low tolerance requirements result in cost and effort savings for the manufacturing of the locking element.

[0022] By arranging the balancing mass on the opposite side of the release lever with respect to the rotational axis of the locking element, the return spring can be designed to be slimmer, in particular with lower preload forces. This simultaneously means that the release unit can also be designed to be slimmer, because lower unlocking forces are required to actuate the locking element into the unlocked position. The parking lock device therefore requires small spring forces and consequently a smaller unlocking unit, while the balancing mass simultaneously provides sufficient protection against impact forces. With such a parking lock device, unintentional unlocking can be prevented in the event of strong impacts, despite the eccentric mounting of the locking element. This avoids unwanted and damaging engagement of a locking pawl, which would otherwise activate the parking lock.

[0023] Preferably, the unlocking unit and the return spring are each arranged on the unlocking lever, in particular on opposite sides of the unlocking lever, and act accordingly on the unlocking lever. In one exemplary embodiment, the unlocking lever has a first shaped section which is assigned to the return spring. The first shaped section is designed to securely receive an axial end section of the return spring. Alternatively or additionally, the unlocking lever has a second shaped section which is assigned to the unlocking unit. The second shaped section serves as a stop or stop surface for actuating the locking element by means of a plunger of the unlocking unit. If the unlocking unit and the return spring are each arranged on the unlocking lever, the aforementioned shaped sections can be arranged in alignment with one another on opposite sides of the unlocking lever.

[0024] The parking lock device preferably further comprises a switching element with which a pawl can be moved into a locked position for locking a parking lock gear, a guide rod on which the switching element is arranged, and an actuator with an actuating member by means of which the guide rod can be linearly displaced. The pawl preferably has a locking tooth designed to lock the parking lock gear in the locked position and to release the parking lock gear in an unlocked position. For example, a locked position of the pawl exists when the pawl is actuated by the actuating unit, so that the pawl is pivoted about the axis of rotation and engages with a locking portion at least partially into the toothing on the parking lock gear to form a positive connection. The rotation of the parking lock gear is blocked by the positive connection between the pawl and the parking lock gear.The pawl consequently blocks the respective shaft of the motor vehicle that is operatively connected to the parking lock gear, in particular the drive shaft or the output shaft of the motor vehicle. The unlocked position of the pawl, on the other hand, occurs when the pawl is not actuated by the actuating unit and is therefore not pivoted about the axis of rotation. The unlocked position corresponds to an initial or neutral position of the pawl. In other words, the pawl is passive in the unlocked position and its locking section does not engage the toothing on the parking lock gear, so that the parking lock is not engaged and thus a drive shaft or output shaft of the motor vehicle is not blocked. Thus, in its unlocked position, the pawl allows rotation of the parking lock gear.

[0025] The actuator's actuating member is connected to the aforementioned actuating element, which can be designed as a sleeve or rod. The actuating element can also be part of the actuator.

[0026] The switching element is preferably designed as a locking cone, which is at least indirectly supported on a housing when the parking lock device is engaged. In other words, the locking cone can be supported fixedly to the frame in the locked position. Additional components can also be arranged between the housing and the locking cone to promote secure support of the locking cone. For example, a sleeve can be provided that is fixedly arranged to the housing, wherein the locking cone of the switching element dips into the sleeve and is supported on it when the parking lock device is engaged. The switching element is preferably arranged movably on the guide rod.

[0027] In most cases, the switching element is spring-loaded, allowing the parking lock to be automatically engaged in the event of an electrical malfunction. The spring preload can be provided by an activation spring that surrounds the guide rod, with the activation spring resting on the switching element and the guide rod. The activation spring can thus rest directly on the switching element at one spring base and on the guide rod at the other.

[0028] To the extent that elements are designated by numbering, for example, "first component," "second component," and "third component," this numbering is intended purely for differentiation in the designation and does not represent a dependency of the elements on one another or a mandatory sequence of the elements. This means, in particular, that a device does not have to have a "first component" in order to have a "second component." The device may also comprise a "first component" and a "third component," but without necessarily having a "second component."

[0029] Further measures improving the invention are described in more detail below together with the description of a preferred embodiment of the invention with reference to the figures. Fig. 1 a schematic view of a parking lock device according to the invention according to a preferred embodiment, Fig. 2 a first schematic partial sectional view of the parking lock device according to the invention according to Fig. 1 and Fig. 3 a second schematic partial sectional view of the parking lock device according to the invention according to Fig. 1 and Fig. 2.

[0030] Fig. 1 shows a parking lock device 1 with a pawl 16 that is rotatable about a rotational axis 23. When the pawl 16 is rotated, a locking tooth 24 formed integrally with it moves substantially along the radial direction with respect to the (not shown) transmission main shaft. The parking lock device 1 is intended for installation in a vehicle transmission of a motor vehicle and causes a parking lock gear 25 to be locked, which is connected in a rotationally fixed manner to the transmission main shaft. The parking lock gear 25 has a locking toothing arranged on its outer circumference, into which the locking tooth 24 can be positively locked. The pawl 16 is held by a return spring 26, which prevents the pawl 16 from inadvertently locking against the parking lock gear 25 due to gravity in the unloaded state. The pawl 16 is actuated according to Fig. 2 by a switching element 15, which in this case has a conical shape and is linearly displaceable on a guide rod 17 and essentially axially parallel to the parking lock gear 25. In a locked position of the pawl 16, the switching element 15 is supported on the back of the pawl 16 and, opposite, on a sleeve 20. The sleeve 20 is fixedly connected to a housing 8.

[0031] The linear displacement of the guide rod 17 is achieved by an actuator 18, which acts on the guide rod 17 via a spring-loaded actuating element 19. For this purpose, the guide rod 17 has a first end face 27 facing the actuating element 19 and formed as a single piece therewith, and the actuating element 19 has a second end face 28 facing the guide rod 17 and formed as a single piece therewith. The first end face 27 is concave and the second end face 28 is convex. The two end faces 27, 28 form a pivot joint about all three axes of rotation, about which the guide rod 17 can pivot during linear displacement. During assembly, the guide rod 17 is pushed with the first end face 27 through a sleeve-shaped actuating element 7, which is then mounted / pressed onto the actuating element 19 with the corresponding mating contour.

[0032] When locking and unlocking or activating or deactivating the parking lock device 1, the guide rod 17 pivots relative to the actuating member 19, so that bending of the guide rod 17 is prevented. In the illustration according to Fig. 2, the guide rod 17 is pushed to the right during locking and pulled to the left during unlocking. In the unlocked position of the pawl 16, the switching element 15 is mechanically preloaded by an activation spring 21 arranged on the guide rod 17 in order to cause a displacement of the guide rod 17 in the direction of the sleeve 20 and a concomitant engagement upon activation of the parking lock and the resulting tooth-on-tooth position between the locking tooth 24 of the pawl 16 and one of the teeth of the parking lock gear 25. In the present illustration, the cone of the switching element 15 moves to the right, preloaded by the activation spring 21, as soon as a tooth-on-gap position for activating the parking lock is achieved by rotation of the parking lock gear 25.

[0033] The parking lock device 1 further comprises a locking unit, which in the sectional view according to Fig. 3 is shown in more detail. This locking unit is designed to lock the pawl 16 in its engaged and / or disengaged position. Fig. 3, a pawl-like or fork-shaped locking element 3 is arranged pivotably about a rotation axis 2. Furthermore, an unlocking unit 6 and a return spring 9 in the form of a spiral spring are provided. The unlocking unit 6 in this case comprises both a lifting magnet 30 with an electromagnetically actuated plunger and an optional hydraulically actuated actuating element in the form of a hydraulically actuated unlocking piston 22. By means of the unlocking piston 22, the locking element 3 can be moved out of the locked position or displaced into the unlocked position even if the lifting magnet 30 fails. The unlocking piston 22 and the lifting magnet 30, i.e. the unlocking unit 6, are arranged together on the same side of the unlocking lever 5.The unlocking piston 22 and the plunger 29 are designed such that when they are actuated (downward in the present illustration), the locking element 3 is pressed about the rotation axis 2 into the unlocked position.

[0034] The locking element 3 comprises a locking lever 4 and an unlocking lever 5 connected to it in one piece. On a side of the rotation axis 2 opposite the unlocking lever 5 and locking lever 4, a balancing mass 10 is arranged in the form of a bolt that is essentially horizontally aligned in the locked position. During operation, impact forces may occur that act on the system. The impact forces act according to the illustration. Fig.3 acts primarily vertically on the system, which is why it is advantageous to arrange the balancing mass 10 transversely, in this case perpendicular, to the direction of action of the impact forces in order to at least partially balance the mass of the release lever 5 and the locking lever 4. For this reason, the balancing mass 10 is arranged or aligned essentially horizontally in the locked position of the locking element 3 or in an initial position. In this example, the longitudinal extent of the bar-shaped balancing mass 10 is arranged essentially flush with the longitudinal extent of the release lever 5. Accordingly, the longitudinal extent of the balancing mass 10 is arranged obliquely to the longitudinal extent of the locking lever 4. The locking lever 4 is arranged in this case at an angle of between 50° and 60° to the release lever 5. Accordingly, the locking lever 4 is arranged at an angle of between 120° and 130° to the bar-shaped balancing mass 10.

[0035] In the present case, the compensating mass 10 is formed integrally with the locking lever 4 and the release lever 5. The locking element 3, comprising the compensating mass 10, the locking lever 4, and the release lever 5, can be stamped from a sheet metal in a single step. Alternatively, it is conceivable to form the compensating mass 10 as a separate additional part and, after the locking element has been manufactured, to attach this to the locking element 3 using a suitable connection. This can be advantageous when the available installation space is limited, for example, if the compensating mass 10 is designed with a higher density, i.e., with a larger mass for a given volume.

[0036] In the present case, the release lever 5 has two shaped sections 13, 14, which are formed in alignment with one another on opposite sides of the release lever 5. The first shaped section 13 is arranged on the underside of the release lever 5 and is assigned to the return spring 9, wherein the return spring 9 is axially supported on a housing 8 and on the release lever 5. The second shaped section 14 is arranged on the opposite upper side of the release lever 5 and is assigned to the release unit 6. The second shaped section 14 rests on the axially displaceable or actuatable plunger 29 of the release unit 6.

[0037] The unlocking lever 5 can be actuated by the unlocking unit 6, i.e. by the plunger 29 and / or the unlocking piston 22, in such a way that the locking element 3 pivots about the rotation axis 2 from a locking position as the initial position or normal position of the locking element 3 into an unlocking position.

[0038] The return spring 9, on the other hand, is operatively connected to the locking element 3 or the release lever 5 in such a way that the locking element 3 is pressed about the rotation axis 2 in the opposite direction, i.e., toward the locked position. Upon actuation of the release lever 5 by the release unit 6, with corresponding rotation of the locking element 3, the return spring 9 generates a restoring force that is intended to automatically return the locking element 3 to the locked position when actuation of the release unit 6 is terminated.

[0039] The locking lever 4 has a locking portion 11 which is designed to engage in an at least partially circumferential locking groove 12 of the actuating element 7 when the locking element 3 comes into the locking position, whereby the actuating element 7 is positively locked in an axial position or a longitudinal displacement of the actuating element 7 is blocked.

Claims

[1] Parking lock device (1) for a transmission of a motor vehicle, comprising a locking element (3) which is pivotally mounted about a rotational axis (2), the locking element (3) comprising a locking lever (4) and an unlocking lever (5) connected in one piece therewith, an unlocking unit (6), an actuating element (7) for activating or deactivating the parking lock device (1), and a return spring (9), wherein the locking element (3) can be actuated by the unlocking unit (6) in such a way that the locking element (3) pivots about the rotational axis (2) from a locked position into an unlocked position, wherein the return spring (9) is operatively connected to the locking element (3) in such a way that the locking element (3) is pressed about the rotational axis (2) into the locked position, wherein a locking section (11) of the locking lever (4) in the locked position engages in an at least partially circumferential locking groove (12) of the actuating element (7) intervenes,to positively lock the actuating element (7) in an axial position, and wherein a balancing mass (10) is arranged on the locking element (3) on a side of the rotational axis (2) opposite to the unlocking lever (5) and / or the locking lever (4). [2] Parking lock device (1) according to claim 1, characterized by that the balancing mass (10) is formed in one piece with the locking lever (4) and the unlocking lever (5). [3] Parking lock device (1) according to claim 1, characterized by that the balancing mass (10) is attached to the locking element (3). [4] Parking lock device (1) according to one of the preceding claims, characterized by that the unlocking lever (5) has a first shaped section (13) which is assigned to the return spring (9). [5] Parking lock device (1) according to one of the preceding claims, characterized bythat the unlocking lever (5) has a second shaped section (14) which is assigned to the unlocking unit (6). [6] Parking lock device (1) according to one of the preceding claims, characterized by a switching element (15) with which a pawl (16) can be moved into a locking position for locking a parking lock wheel, a guide rod (17) on which the switching element (15) is arranged, and an actuator (18) with an actuating member (19) by means of which the guide rod (17) can be moved linearly. [7] Parking lock device (1) according to claim 6, characterized by that the switching element (15) is designed as a locking cone which, in the engaged state of the parking lock device (1), is supported at least indirectly on a housing (8). [8] Parking lock device (1) according to claim 6 or claim 7, characterized by that the switching element (15) is movably arranged on the guide rod (17). [9] Parking lock device (1) according to one of claims 6 to 8, characterized by that the guide rod (17) is enclosed by an activation spring (21) which is supported on the switching element (15) and on the guide rod (17). [10] Parking lock device (1) according to one of the preceding claims, characterized by that the unlocking unit (6) comprises a lifting magnet (30) and / or a hydraulically actuated actuating element, wherein the unlocking unit (6) is operatively connected to the locking element (3) in such a way that the locking element (3) is pressed about the rotation axis (2) into the unlocking position.

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