Device for actuating a locking mechanism, in particular for actuating a parking lock device

Abstract

A device (1) for actuating a locking mechanism (2), in particular for actuating a parking lock device of a vehicle drive train equipped with an automatic transmission, comprising at least one piston unit (4) spring-loaded in the closing direction (S) of the locking mechanism (2) and hydraulically actuable in the opening direction of the locking mechanism (2), a latching device (5) for holding the piston unit (4) at least in axial positions equivalent to the open and closed states of the locking mechanism (2), and an actuating device (6) with an electromagnet (15) for actuating a release element (7) which can be acted upon by an electromagnetic actuating force to switch the latching device (5) between an operating state holding the piston unit (4) and an operating state releasing the piston unit (4).wherein the piston unit (4) is held by the locking device (5) in its position equivalent to the closed state of the locking mechanism (2) in the de-energized operating state of the electromagnet (15), characterized in that the locking device (5) is designed with at least one spring arm (16, 17) which can be brought into operative connection with the piston unit (4) both in the axial position of the piston unit (4) equivalent to the open state and in the axial position equivalent to the closed state of the locking mechanism (2), by means of which spring arm the piston unit (4) can be held in the axial position equivalent to the open state and the axial position equivalent to the closed state of the locking mechanism (2).

Description

The invention relates to a device for actuating a locking mechanism, in particular for actuating a parking lock device, according to the type defined in more detail in the preamble of claim 1.From the post-published DE 10 2012 210 571 A1 of the applicant, a device for actuating a locking mechanism, in particular for actuating a parking lock device of a drive train of a vehicle embodied with an automatic transmission, is known. The device has a piston unit arranged displaceably in the axial direction, a latching device, which automatically activates in an axial position of the piston unit equivalent to an open state of the locking mechanism, for holding the piston unit in the axial position equivalent to the open state of the locking mechanism, and an actuating device for actuating a release element which is provided for deactivating the latching device. The latching device is designed to automatically activate the piston unit in an axial position equivalent to a closed state of the locking mechanism and to deactivate it in order to release a movement of the piston unit starting from the axial position equivalent to the closed state of the locking mechanism in the direction of the axial position equivalent to the open state of the locking mechanism.The device represents part of an electrohydraulic parking lock actuation and is also referred to as a parking lock actuator, by means of which the parking lock of a vehicle can be held in the disengaged position without hydraulic pressure supply. The disengagement of the parking lock is effected by means of a hydraulic pressure which adjusts the piston unit or a cylinder from a first end position, to which the parking lock is engaged, into a second end position, in which the parking lock is disengaged. The engagement of the parking lock is carried out via a spring return mechanism, wherein the electromagnetic locking mechanism of the device prevents an undesired engagement of the parking lock against the force of the return mechanism in the unpressurized state. In addition, disengagement of the parking lock is prevented by the latching device even in the event of a fault, such as an undesired hydraulic control of the piston unit, which device mechanically locks disengagement of the parking lock by active energization of an electromagnet when the parking lock is engaged. A vehicle is thus secured against undesired starting even during a so-called remote start of a vehicle.However, it is problematic here that the disengagement of the parking lock is not ensured to a required extent in the event of a failure of the power supply of the device and simultaneous undesired pressurization of the piston unit.Further parking locks for motor vehicles are known from DE 10 2010 032 733 A1, DE 10 2011 105 380 A1, JP 2008-128 444 A, 42 21 230 C1 and DE 43 23 846 C1.The present invention is therefore based on the object of providing a device for actuating a locking mechanism, in particular for actuating a parking lock device, by means of which an undesired disengagement of a parking lock is reliably avoided.According to the invention, this object is achieved by a device having the features of claim 1.In the device according to the invention for actuating a locking mechanism, in particular for actuating a parking lock device of a drive train of a vehicle embodied with an automatic transmission, which has at least one piston unit sprung in the closing direction of the locking mechanism and hydraulically actuatable in the opening direction of the locking mechanism, a latching device for holding the piston unit at least in axial positions equivalent to the open and closed states of the locking mechanism, and an actuating device with an electromagnet for actuating a release element, which can be acted upon by an electromagnet-side actuating force for switching the latching device between an operating state holding the piston unit and an operating state releasing the piston unit, the piston unit is held in its position equivalent to the closed state of the locking mechanism in the non-energized operating state of the electromagnet by the latching device, which preferably automatically activates the operating state depending on the operating state.The latching device is designed with at least one spring arm which can be brought into operative connection with the piston unit both in the axial position of the piston unit which is equivalent to the open state and in the axial position of the piston unit which is equivalent to the closed state of the locking mechanism, by means of which spring arm the piston unit can be held in the axial position which is equivalent to the open state and in the axial position which is equivalent to the closed state of the locking mechanism.Thus, with the device according to the invention, it is ensured in a structurally simple and space-saving manner that the locking mechanism or a parking lock device is not transferred into its open operating state in the event of a failure of a power supply contrary to a corresponding requirement even in the event of an erroneous pressurization of the piston unit.In an advantageous embodiment of the device according to the invention, the plunger unit is held by the latching device in its position equivalent to the open state of the locking mechanism in the energized operating state of the electromagnet. This in turn ensures that the locking mechanism can be held in the open operating state by active energization and, in the event of a fault, i.e. in the event of a failure of the power supply, can be transferred by the spring-biased piston unit into its closed operating state or a parking lock device can be inserted in order to be able to secure a vehicle embodied with the device against undesired rolling away.The device according to the invention can be operated with little effort if the spring arm is designed with a spring force prestress which pivots the spring arm at least in the axial position equivalent to the open state of the locking mechanism into its position locking the piston unit, wherein the spring arm is firmly connected with the actuating device by its end facing away from the piston unit, so that the spring force prestress of the spring arm can be supported on the latter.If the spring arm is guided by the spring force prestress into engagement with the piston unit towards the operating state of the spring arm, towards which the piston unit is held by the spring arm in the axial position equivalent to the open state of the locking mechanism, the latching device is designed automatically activating in the open state of the locking mechanism and can therefore be actuated with little effort.In a further advantageous embodiment of the device according to the invention, the spring arm is guided by the release element counter to the spring force prestress in engagement with the piston unit towards the operating state of the spring arm, towards which the piston unit is held by the spring arm in the axial position equivalent to the closed state of the locking mechanism, whereby the latching device can be actively transferred in the closed state of the locking mechanism into its operating state locking the piston unit.In an embodiment of the device according to the invention which is particularly advantageous in terms of installation space and can be produced easily, the spring arm is surrounded at least in regions in the radial direction by a sleeve region which can be displaced with the piston unit in the axial direction with respect to the spring arm, wherein the spring arm can be guided by the release element with a latching region in the axial position of the piston unit which is equivalent to the closed state of the locking mechanism into a latching groove arranged in an inner radius region of the sleeve region, in order to be able to lock the piston unit to the desired extent.If the inner radius of the inner radius region of the sleeve region is smaller than an inner radius of a further inner radius region of the sleeve region, which surrounds an inner locking section of the piston unit, which can be overlapped by the spring arm in the axial position of the piston unit equivalent to the open state of the locking mechanism, in the radial direction, it is ensured that the spring arm can be moved to the desired extent out of engagement with the locking section and, on the other hand, the spring arm can be securely transferred by the spring arm into the latching groove of the sleeve region without loss of contact with the release element.If a surface of the release element facing the spring arm is matched to a surface of the spring arm facing the release element and an inner side of the sleeve region is matched to an outer side of the spring arm facing the sleeve region, such that a pivoting movement of the spring arm in the direction of a blocking section of the piston unit is released by the release element in the energized state of the electromagnet and the spring arm can be moved by the release element out of the engagement of the blocking section in the non-energized state of the electromagnet, the device according to the invention is of a structurally simple design and can be operated with little control and regulating effort.In a likewise structurally simple embodiment of the device according to the invention, which can additionally be operated with little control and regulating effort, the surface of the release element facing the spring arm is matched to the surface of the spring arm facing the release element and the inside of the sleeve region is matched to the outside of the spring arm facing the sleeve region, such that a pivoting movement of the spring arm in the direction of the sleeve region of the piston unit is enforced by the release element in the non-energized state of the electromagnet, and a pivoting movement of the spring arm, which leads the spring arm out of the engagement of the latching groove, is enabled by the release element in the energized state of the electromagnet.A further embodiment of the device according to the invention is designed with a latching device having at least two spring arms, wherein the piston unit can be locked in its axial position equivalent to the open state of the locking mechanism by means of one of the spring arms in the energized state of the electromagnet, while the piston unit can be held by the other spring arm in its axial position equivalent to the closed state of the locking mechanism in the non-energized state of the electromagnet.In the embodiment of the device according to the invention with two spring arms, it is possible to design the release element as a double-acting locking cone of opposite design, which can be actuated via the electromagnet. In this case, it can be provided to actuate the spring arms to the desired extent in the same actuating direction, as a result of which only simple activation of the electromagnet is required in each case in order to unlock the respective position or the respectively present operating state of the locking mechanism. In this case, an actuation of the spring arms in the radial direction both outwards and inwards is conceivable.The actuation of the spring arms radially outwards can be implemented, for example, by means of a so-called inner cone, while actuation of the spring arms radially inwards can be implemented structurally by means of a release element embodied as an outer ring.In a cost-effective and structurally simple development of the device according to the invention, the spring arms are of identical design and interact with a rotationally symmetrical release element, wherein the spring arms are mounted offset with respect to one another in the axial direction with respect to the release element and, depending on the axial position of the piston unit and the release element with respect to one another, are alternately in blocking engagement with the piston unit or can be guided out of engagement with the piston unit by the release element.An alternative embodiment of the device according to the invention to this end is formed with identical spring arms which cooperate with a non-rotationally symmetrical release element, are mounted at the same height in the axial direction with respect to the release element and, depending on the axial position of the piston unit and the release element with respect to one another, are alternately in locking engagement with the piston unit or can be guided out of engagement with the piston unit by the release element.If the piston unit is formed with latching regions which are arranged offset with respect to one another in the axial direction and which cooperate with the spring arms in each case in a circumference arresting the piston unit or are disengaged from the spring arms depending on a position of the release element dependent on the operating state of the electromagnet, the piston unit can be held with little structural complexity in the axial position equivalent to the open operating state or in the axial position equivalent to the closed operating state of the locking mechanism.In principle, the locking mechanism or the parking lock device can be transferred into the opened or disengaged operating state only in the normal case, i.e. with the electromagnet being supplied with power accordingly and by appropriate printing on the piston unit. Without suitable actuation pressure, the locking mechanism cannot be transferred into its open operating state. In addition, even in the event of a failure of the power supply to the electromagnet, the locking mechanism cannot be transferred into its open operating state even when the piston unit is appropriately pressurized.In order to be able to transfer the locking mechanism from its closed operating state into its open operating state in the event of a failure of the electrical supply of the electromagnet and without correspondingly available actuating pressure, the piston unit in a further advantageous embodiment of the device according to the invention is connected to a ratchet disk which can be set in rotation as a function of an axial adjustment of the piston unit and which can be brought into operative connection with the locking mechanism via a rod element, wherein a manually triggerable relative movement can be produced between the ratchet disk and the piston unit, via which relative movement the locking mechanism can be transferred manually from its closed operating state into its open operating state independently of a current operating state of the piston unit, when the latter is in the closed operating state.It is possible to connect the detent disk to the piston unit via a lever region which is arranged in an elongated hole of the piston unit such that it can move with respect to the piston unit, and to guide the detent disk to the lever via a torsion spring against a stop of the piston unit. The detent disk is then pivotable in the slot counter to the spring force of the torsion spring together with the lever element with respect to the piston unit axially fixed in the event of a fault. The locking mechanism can be opened or the parking lock can be disengaged by the pivoting movement or rotational movement of the ratchet disk, wherein the ratchet disk can be configured to be manually drivable by an operator via a cable pull or the like for this purpose.Both the features specified in the patent claims and the features specified in the following exemplary embodiments of the device according to the invention are each suitable, alone or in any combination with one another, for further developing the subject matter according to the invention. The respective combinations of features do not represent any restriction with respect to the development of the subject matter according to the invention, but essentially merely have an exemplary character.Further advantages and advantageous embodiments of the device according to the invention are evident from the patent claims and the exemplary embodiments described in principle below with reference to the drawing, wherein the same reference numerals are used for components having the same construction and function in the description of the different exemplary embodiments for the sake of clarity.It shows: FIG. 1 is a schematic partial longitudinal section view of a first embodiment of the device according to the invention for actuating a parking lock device when the parking lock is engaged; FIG. 2 shows a representation corresponding to FIG. 1 of the first embodiment of the device with the parking lock disengaged; FIG. 3 shows a highly schematic individual illustration of a spring arm and a release element of the device according to FIG. 1 with the parking lock disengaged; FIG. 4 shows a representation corresponding to FIG. 3 of the spring arm and the release element in relation to an operating state which is present between an engaged operating state and a designed operating state of the parking lock; FIG. 5 shows the release element and the spring arm in a representation corresponding to FIG. 3 with the parking lock disengaged; FIG. 6 shows an enlarged individual view of a region VI identified in more detail in FIG. 1 ; FIG. 7 shows a detailed longitudinal sectional view of the device according to FIG. 1, which is operatively connected to a locking mechanism via a ratchet disk and a rod element, in the engaged state of the parking lock; FIG. 8 shows a representation corresponding to FIG. 7 of the device with the parking lock disengaged via a piston unit; FIG. 9 shows a representation corresponding to FIG. 7 of the device with the parking lock disengaged via emergency unlocking; FIG. 10 is a schematic longitudinal sectional view of a second embodiment of the device according to the invention in the engaged state of the parking lock; FIG. 11 shows a representation corresponding to FIG. 10 of the second embodiment of the device according to the invention in the disengaged state of the parking lock; FIG. 12 shows a representation corresponding to FIG. 10 of a third embodiment of the device according to the invention in the engaged state of the parking lock; FIG. 13 shows a representation corresponding to FIG. 12 of the third embodiment of the device according to the invention in the disengaged state of the parking lock; FIG. 14 shows a representation corresponding to FIG. 10 of a fourth embodiment of the device according to the invention in the engaged state of the parking lock; FIG. 15 shows a representation corresponding to FIG. 14 of the fourth embodiment of the device according to the invention in the disengaged state of the parking lock; FIG. 16 shows a representation corresponding to FIG. 10 of a fifth embodiment of the device according to the invention in the engaged state of the parking lock; FIG. 17 shows a representation corresponding to FIG. 16 of the fifth embodiment of the device according to the invention in the disengaged state of the parking lock; and FIG. 18 shows the device according to FIG. 16 from a view XVIII marked in more detail in FIG. 16.FIG. 1 shows a schematic partial longitudinal section view of a first embodiment of a device 1 for actuating a parking lock device 2, which is designed in the present case as a parking lock device of a drive train of a vehicle designed with an automatic transmission. The device 1 has, in a manner known per se, a piston unit 4, which can be acted upon by a fluid and can be actuated in the opening direction of the parking lock device 2 as a function of a fluid pressure p counter to a spring device acting in the closing direction S of the parking lock device 2 and is arranged displaceably in the axial direction in a cylinder 3, and is connected to the parking lock device 2 in a manner illustrated in more detail in FIGS. 7 to 9. The piston unit 4 is supplied in the present case via a so-called parking lock valve 13 with a system pressure p_sys of a hydraulic system of an automatic transmission when the parking lock device 2 is to be disengaged.Furthermore, the device 1 is designed with a detent device 5, which can be activated in an axial position of the piston unit 4 that is equivalent to an open state of the parking lock device 2 and is shown in more detail in FIG. 2, for holding the piston unit 4 in the axial position that is equivalent to the open state of the parking lock device 2. The detent device 5 is designed automatically activating in an axial position of the piston unit 4 shown in more detail in FIG. 1 and equivalent to a closed state of the parking lock device 2, in order to be able to hold the piston unit 4 in the axial position equivalent to the closed state of the parking lock device 2.The device 1 also has an electromagnetic actuating device 6 for actuating a release element 7, by means of which the latching device 5 can be activated or deactivated in the manner described later. The release element 7 is connected to an anchor rod 8 and is arranged together with the anchor rod 8 and an anchor element 9 operatively connected thereto in a longitudinally movable manner in the interior of the cylinder 3. The release element 7, the anchor rod 8 and the anchor element 9 can each be acted upon by an actuating force acting in the direction of a position equivalent to the deactivated operating state and to the activated operating state of the latching device 5. For this purpose, a spring device 11 is provided, which is arranged between a component 12 fixed to the housing and the release element 7 and is pushed onto the anchor rod 8. When the parking lock device is open and the locking device 5 is activated at the same time, the spring force of the spring device acts on the piston unit 4, which spring force would like to displace the piston unit 4 against the holding force of the locking device 5 in the closing direction S illustrated in FIG. 1. It is possible to design the spring device as a compression or tension spring in order to apply an axial actuating force to the piston unit 4 away from the electromagnetic actuating device 6.The device 1 shown in FIGS. 1 to 9 has the following mode of operation in the normal operating mode, during which the piston unit 4 can be supplied with the fluid pressure p in the region of an effective surface 14 and the electromagnetic actuating device 6 can be supplied with current:In addition to the operating state of the device 1 shown in FIG. 1, the piston unit 4 is in the axial position equivalent to the closed operating state of the parking lock device 2 or in the axial position equivalent to the engaged operating state of the parking lock device or in a first end position in which the piston unit 4 is held by the activated locking device 5. For this purpose, energization of an electromagnet 15 of the actuating device 6 is interrupted and the release element 7, together with the armature element 9 and the armature rod 8, is displaced by the spring force of the spring device 11 from the position illustrated in FIG. 2 in the axial direction in the cylinder 3 in the direction of the axial position illustrated in FIG. 1. Locking elements which are arranged distributed over the circumference of the release element 7 and are in the present case embodied as spring arms 16, 17 and are fixedly connected at one end to the component 12 fixed to the housing and whose end opposite in the axial direction is freely embodied are pivoted radially outwards by the release element 7 in the manner described in more detail with respect to FIGS. 3 to 5 until they engage with a latching region 18 in a latching groove 19 shown in more detail in FIG. 6, wherein the piston unit 4 for this purpose is to be adjusted by the spring device into the axial position shown in FIG. 1 and equivalent to the closed operating state of the parking lock device 2. The latching groove 19 is provided in an inner radius region of a sleeve region 20 of the piston unit 4 and is formed with a defined groove depth t. Thus, when the latching regions 18 engage in the latching groove 19, the spring arms 16, 17 pivot radially further outward by the groove depth t, so that the release element 7 fixes the spring arms 16, 17 beyond the conical surface with the cylinder lateral surface.FIG. 3 shows a highly styletized representation of the release element 7 and the locking element in the form of a spring arm 16 in relation to the operating state of the device 1 shown in FIG. 2, in relation to which the electromagnet 15 is present in the energized state and the locking element in the form of a spring arm 16 is pivoted completely radially inward about the clamping region in the component 12 fixed to the housing and abuts a conical region 22 of the release element 7 with a region 21 projecting in the direction of the release element 7. The locking element in the form of a spring arm 16 and also the locking element in the form of a spring arm 17 are in the present case designed with a spring force prestress which holds the locking elements in the form of the spring arms 16 and 17 or pivots them into the position illustrated in FIGS. 2 and 3. The locking elements in the form of the spring arms 16 and 17 are thereby firmly connected to the component 12 of the actuating device 6 fixed to the housing in such a way that the spring bias of the locking elements in the form of the spring arms 16 and 17 can be supported on the latter.In order to be able to transfer the blocking element in the form of the spring arm 16 and thus also the blocking element in the form of the spring arm 17 not shown in more detail in FIG. 3 from the pivoted position shown in FIGS. 2 and 3 into the pivoted position shown in FIGS. 1 and 5, the energization of the electromagnet 15 is interrupted and the release element 7 is displaced by the spring device 11 together with the armature element 9 and the armature rod 8 in the axial direction. In this case, the protruding region 21 of the spring arm 16 slides along the conical region 22 of the release element 7 in the manner illustrated in FIG. 4 until the protruding region 21 reaches a cylindrical surface region 23 and the spring arm 16 is adjusted by the release element 7 into the position which is pivoted radially outwards and is illustrated in FIGS. 1 and 5.If the latching of the piston unit 4 by the latching device 5 illustrated in FIG. 1 is intended to be canceled again because there is a request for disengagement of the parking lock device 2, the energization of the electromagnet 15 is restored and the release element is transferred, counter to the spring device 11 which is embodied in the present case as a compression spring, together with the armature rod 8 and the armature element 9, from the position illustrated in FIG. 1 into the axial position shown in FIG. 2. Due to their spring prestress, the spring arms 16 and 17 move with increasing displacement travel of the release element 7 from the position shown in FIG. 1 into the position shown in FIG. 2 and pivoted radially inward. The latching regions 18 slide out of the latching groove 19, as a result of which the form-fitting connection between the latching device 5 and the piston unit 4 is separated. If the piston unit 4 is acted upon by actuating pressure p in the region of the effective surface 14 via the parking lock valve 13, the piston unit 4 is increasingly transferred from the position shown in FIG. 1 into the axial position shown in FIG. 2, which is equivalent to the open operating state of the parking lock device 2 or to the designed operating state of the parking lock device 2.As the displacement path of the piston unit 4 increases in the direction of the actuating device 6, an overlap region between the piston unit 4 and the spring arms 16 and 17 and the release element 7 increases. Starting from a defined displacement path of the piston unit 4, the piston unit 4 comes with an inner blocking section 24 into contact with the spring arms 16 and 17 pivoted in in the radial direction. The inner blocking section 24 is in the present case designed with a conical region 25 which increases increasingly from its end facing the actuating device 6 in the direction of its second end facing the active surface 14 and thus forms a guide slope for the spring arms 16 and 17, by means of which jamming is reliably prevented during the spreading of the spring arms 16 and 17.If the piston unit 4 strikes the free ends of the spring arms 16 and 17 with its inner blocking section 24 or the conical region 25, the spring arms 16 and 17 are pivoted outwards by the inner blocking section 24 from the pivoted position shown in FIG. 2 with increasing displacement path of the piston unit 4 and then drop radially inwards behind the conical region 25 when further inwardly projecting latching regions 26 of the spring arms 16 and 17 are disengaged from the conical region 25 of the inner blocking section 24 of the piston unit 4. For this purpose, the blocking section 24 is formed behind the conical region 25 with respect to the actuating device 6 with a cylindrical region 27 of smaller diameter, which permits the latter pivoting movement of the spring arms 16 and 17 into the pivoting position illustrated in FIG. 2.If the actuating pressure p that is exerted by the parking lock device 2 and can be applied in the region of the effective surface 14 falls and there is no corresponding request for engaging the parking lock device 2, the piston unit 4 is displaced by the spring device acting on the piston unit 4 from the axial position shown in FIG. 2 in the direction of the axial end position of the piston unit 4 shown in FIG. 1 until the inner locking section 24 comes to bear with an annular disk-shaped region 28 against the further locking regions 26 of the spring arms 16 and 17, as a result of which the piston unit 4 is held by the spring arms 16 and 17 in the axial position equivalent to the designed operating state of the parking lock device 2.If there is a corresponding request for engaging the parking lock device 2, the energization of the electromagnet 15 is again interrupted in order to be able to displace the release element 7 from the position illustrated in FIG. 2 in the direction of the axial position shown in FIG. 1. When the electromagnets 15 are not energized, the release element 7 is pushed between the spring arms 16 and 17 and moves the latter out of engagement with the inner locking section 24 of the piston unit 4, which is then displaced by the spring device into the axial position equivalent to the engaged operating state of the parking lock device 2.In order to ensure that the detent device 5 is reliably activated in order to hold the piston unit 4 in the disengaged operating state of the parking lock device 2, a sliding element 29 which can be displaced in the axial direction is provided in the interior of the locking section 24, said sliding element being pressed by a spring device 30 against a spring ring 31, which in turn is fixedly arranged in the axial direction in an inner groove 32. With this embodiment of the device 1 which is advantageous in terms of installation space in the axial direction, it is possible to introduce the anchor rod 8 which reaches through the release element 7 in the axial direction into the interior of the blocking section 24 in some areas with its end facing the inner blocking section 24, and to guide the spring arms 16 and 17 with their further latching regions 26 safely past the conical region 25 and subsequently to be able to enable the desired latching effect by bearing the further latching regions 26 against the annular-disc-shaped region 28 of the blocking section 24. In order to illustrate the axial displacement path of the piston unit 4 relative to the armature rod 8, which displacement path may be required for this purpose, the end of the armature rod 8 facing the inner blocking section 24 can be introduced into the blocking section 24, wherein the spring device 30 is compressed and the sliding element 29 is lifted from the spring ring 31. If the actuating pressure p falls in the region of the effective surface 14, the piston unit 4 is moved back again in the closing direction S by the spring device until the annular disk-shaped region 28 comes to rest against the further latching regions 26 of the spring arms 16 and 17, wherein during this movement of the piston unit 4 the armature rod 8 is carried out again from the interior of the blocking section 24 and the spring device 30 presses the sliding element 29 against the spring ring 31.In order to avoid an undesired deactivation of the latching device 5 in the operating state of the device 1 shown in FIG. 1 and at the same time not to prevent a desired deactivation of the latching device 5 from the operating state of the device 1 shown in FIG. 2, the inner radius of the inner radius region of the sleeve region 20, in which the latching groove 19 is provided, is smaller than an inner radius of a further inner radius region of the sleeve region 20, which surrounds the inner locking section 24 of the piston unit 4, which inner locking section can be overlapped by the spring arm 16, 17 in the axial position of the piston unit 4 equivalent to the closed state of the parking lock device 2, in the radial direction and in turn adjoins an inclination following the inner diameter region in the axial direction.This ensures that a sufficiently large pivot range is available for the spring arms 16 and 17 for releasing the latching device 5, starting from the operating state of the device 1 shown in FIG. 2, to which the parking lock device 2 is designed. Furthermore, the different dimensioning of the inner diameter of the sleeve region 20 ensures that the positive connection between the spring arms 16 and 17 or their latching regions 18 and the latching groove 19 is unintentionally released without the above-described axial adjustment of the release element 7 on account of manufacturing tolerances and possible load-dependent deformations of the spring arms 16 and 17. Thus, the spring arms 16 and 17 can be securely guided out of engagement with the blocking section 24 on the one hand and can be securely held in the latching groove 19 on the other hand.FIGS. 7 to 9 each show a more detailed longitudinal sectional view of the device 1 according to FIG. 1, which, in addition to the components of the device 1 shown in FIGS. 1 and 2, also shows the parking lock device 2 and a ratchet disk 33 coupling the piston unit 4 to the parking lock device 2, which is operatively connected to the piston unit 4 in the region of an elongated hole 34.The detent disk 33 is rotatably mounted in the region of a bolt 35 and is pressed by a leg spring, not shown in detail, against a stop 36 in the slot 34 of the piston unit 4. In the region of a coupling point 37, a parking lock rod 38 is firmly connected to the ratchet disk 33, via which a rotational movement of the ratchet disk 33 can be transmitted to a parking lock cone 39. The parking lock cone 39 interacts with a parking lock pawl 40, which engages with one region into a toothing of a parking lock wheel 41 in a manner known per se when the parking lock device 2 is engaged. The parking lock gear 41 is in turn connected to the output of a vehicle, whereby when the parking lock device 2 is engaged, the output of a vehicle is held in a rotationally fixed manner by the parking lock pawl 40 engaging into the parking lock gear 41. The parking lock cone 39 is arranged on the parking lock rod 38 so as to be longitudinally displaceable and is pressed against a stop 43 by means of a compression spring 42.The longitudinally movable embodiment of the parking lock cone 39 on the parking lock rod 38 and the corresponding springing of the parking lock cone 39 via the compression spring 42 is provided for the purpose that the rotational movement of the ratchet disk 33 to be carried out when a request for engaging the parking lock exists and thus a substantially translatory adjustment of the parking lock rod 38 can be carried out despite the presence of a so-called tooth-on-tooth position between the parking lock pawl 40 and the parking lock wheel 41, in which the parking lock pawl 40 initially does not fall into the parking lock wheel 41 to the desired extent. Until the time at which the parking pawl 40 falls into the parking ratchet wheel 41, the compression spring 42 is prestressed on account of the parking lock cone 39 not adjusted by the parking lock rod 38. If the parking pawl 40 enters the parking ratchet wheel 41 to the desired extent, the parking lock cone 39 can transition into its position equivalent thereto, wherein the compression spring 42 relaxes during this actuating movement of the parking lock cone 39.If the parking lock device 2 cannot be deployed to the described extent due to an insufficient pressure on the effective surface 14 of the piston unit 4, the device 1 is designed with a so-called emergency release 44, which is designed with a cable pull 45 in the present case. By means of the cable pull 45, it is possible for an operator to transfer the ratchet disk 33 from the rotational position shown in FIG. 7 into the rotational position shown in FIG. 9 manually and without hydraulic pressure applied in the region of the piston unit 4 and to disengage the parking lock device 2. For this purpose, the slot 34 is designed to be extended by a length X compared to conventionally designed systems and a lever region 46 of the ratchet disk 33, which is arranged in the slot 34, and thus the ratchet disk 33 itself, is movable relative to the piston unit 4 to the extent required for disengagement of the parking lock device 2. The ratchet disk 33 is adjusted relative to the piston unit 4 by means of the cable 45 and the parking pawl 40 is pulled out of engagement with the parking ratchet wheel 41, although the piston unit 4 itself is not adjusted in the axial direction to the extent required for this purpose. The detent disk 33 is lifted with its lever region 46 from the stop 36 via the cable pull 45 connected to the detent disk 33 in the region of a further coupling point 47 and guided against a further stop 48, wherein the parking lock device 2 is safely designed when the lever region 46 of the detent disk 33 abuts against the further stop 48.FIG. 8 shows an intermediate position of the ratchet disk 33, which is in each case traveled over during a change in operating state of the parking lock device 2 starting from its engaged or disengaged operating state in the direction of its engaged or disengaged operating state with the piston unit 4 simultaneously appropriately axially adjusted.FIGS. 10 to 18 show four further embodiments of the device 1, which in each case differ substantially in the region of the latching device 5 from the first embodiment shown in FIGS. 1 to 6, for which reason in the following description of FIGS. 10 to 18 the differences from the first embodiment of the device 1 according to FIGS. 1 to 6 are respectively discussed in more detail and with regard to the further mode of operation of the different embodiments of the device 1 according to FIGS. 10 to 18 reference is made to the above description of FIGS. 1 to 9.In order to be able to describe and illustrate the mode of operation of the devices 1 according to FIGS. 10 to 17 to a simpler extent, the spring arms 16 and 17 acting alternately in a locking or releasing manner are each pivoted into the plane of the drawing. In order, however, to be able to provide symmetrical force conditions, the devices 1 according to FIGS. 10 to 17 are each designed in the manner shown in FIG. 18 with two opposite spring arms 16A, 16B and 17A, 17B, which are each pivoted radially outwards by the release element 7 simultaneously or, when the release element 7 is in a corresponding position with respect to the spring arms 16A to 17B, each perform a corresponding pivoting movement in the direction of the piston unit 4 and the release element 7 simultaneously due to their spring force prestress and which are each arranged offset from one another by 90° over the circumference of the release element 7 or the piston unit 4.The devices 1 according to FIGS. 10 to 17 each represent a parking lock device 2 with a double-acting, opposite locking cone which is actuated via a magnetic drive in order to actuate different locking elements or locking pawls. In each case, at least one of the ratchet pawls prevents the disengagement of a parking lock device in the first de-energized position of an electromagnet, while the other ratchet pawl prevents the parking lock from engaging in the non-pressurized state of the device 1 in the energized operating state of the electromagnet. Due to the identical actuation direction of the ratchets via the release element 7 or the locking cone, wherein the actuation direction can optionally be directed radially outwards or inwards, but always to be provided in the same direction, only a simple actuation of the electromagnet is required for unlocking the respective position.A second embodiment of the device 1 is shown in FIG. 10, which is designed in the region of the latching device 5 with locking elements in the form of the spring arms 16 and 17 distributed over the circumference of the release element 7, which locking elements are designed identically. However, the spring arm 16 is connected to the component 12 fixed to the housing offset in the axial direction or in the closing direction S with respect to the spring arm 17, whereby the protruding region 21 of the spring arm 16 bears against a surface region of the release element 7 other than a protruding region 49 of the spring arm 17 functioning as a blocking element in the manner illustrated in FIGS. 10 and 11.FIG. 10 shows the device 1 in an operating state which is equivalent to the engaged operating state of the parking lock device 2 and to which the spring arm 17 is guided out of engagement with the piston unit 4 by the release element 7, while the spring arm 16 has fallen radially inward on account of its spring prestress and in the present case blocks an actuating movement of the piston unit 4 counter to the closing direction S, which would cause the parking lock device 2 to be disengaged, in a positive-locking manner via a latching region 50.If there is a corresponding request for disengagement of the parking lock device 2, the electromagnet 15 of the actuating device 6 is energized and the release element 7 is axially adjusted in the axial direction counter to the spring force of the spring device 11 in the direction of the electromagnet 15. This has the result that the projecting region 21 slides on the outer side of the release element 7 and the spring arm 16 is transferred from the pivoted position shown in FIG. 10 into the pivoted-out radial position shown in FIG. 11. At the same time, the spring arm 17 drops radially inward due to its spring prestress, since the release element 7 releases this pivoting movement due to its falling shape. An axial adjusting movement of the piston unit 4 in the closing direction S is prevented in a simple manner by the form fit between the latching region 51 of the spring arm 17 and the piston unit 4. A movement of the piston unit 4 in the closing direction S is only possible again in the normal mode of operation of the device 1 when the actuating pressure in the region of the effective surface 14 of the piston unit 4 is correspondingly lowered and the energization of the electromagnet 15 is interrupted. The release element 7 is then adjusted by the spring device 11 from the axial position shown in FIG. 11 into the axial position shown in FIG. 10, and the spring arm 17 is pressed radially outwards by the release element 7 from the pivot position shown in FIG. 11. At the same time, the spring arm 16 pivots radially inward by the spring force prestress when the piston unit 4 reaches the axial position illustrated in FIG. 10.The latching device 5 and the piston unit 4 cannot be mounted rotationally securely with respect to one another because of the rotationally symmetrical embodiment. In contrast to this, the latching device 5 and the piston unit 4 of the apparatus 1 according to FIGS. 12 and 13 are designed to be rotationally secure with respect to one another, since the spring arm 16 with its latching region 50 and the spring arm 17 with its latching region 51 can be brought into engagement in each case with a latching region 52 or 53 of the piston unit 4, which latching region extends over the circumference of the piston unit 4 only in regions. In this third embodiment of the device 1, a relative rotational movement between the latching device 5 and the piston unit 4 has the effect that the above-described latching functionality of the device is not available to the desired extent, since the spring arms 16 and 17 can then under certain circumstances no longer be brought into engagement with the piston unit to the intended extent.The latching regions 52 and 53 of the piston unit 4 are each designed in regions in the shape of truncated cones, wherein a clamping during an axial relative movement between the spring arms 16 and 17 and the piston unit 4 is to be avoided via the conical surfaces of the latching regions 52 and 53. In contrast to this, the essentially straight regions of the latching regions 52 and 53 of the piston unit 4 in the radial direction cooperate with the spring arm 16 or the spring arm 17 with a high degree of blocking or with a high adhesion effect in order to illustrate the locking of the piston unit 4.The fourth embodiment of the device 1 shown in FIGS. 14 and 15 differs from the third embodiment of the device 1 shown in FIGS. 12 and 13 only in the region of the release element 7, which, in the embodiment of the device according to FIGS. 12 and 13, is formed like a roller as a rotationally symmetrical body, which in turn is likewise substantially symmetrical in the axial direction. In this case, the diameter of the release element 7 according to FIG. 2 is the greatest in the axial extent in the middle and decreases steadily, at least in regions, in the axial direction of its two outer sides. In contrast to this, the release element 7 according to FIG. 14 has its smallest diameter in a central region, which again increases steadily at least in regions in the direction of the edge regions of the release element 7.In the fifth embodiment of the device 1 shown in FIGS. 16 and 17, the identically designed spring arms 16 and 17 are connected to the component 12 fixed to the housing without axial offset from one another. In order to pivot the two spring arms 16 and 17 alternately radially in the manner described with reference to FIGS. 10 to 15, the device 1 has a non-rotationally symmetrical release element 7. The region of the release element 7 pivoting the spring arm 16 radially outwards is designed to be larger with respect to the axis of symmetry 54 of the device 1 than the region of the release element 7 interacting simultaneously with the spring arm 17. in addition, the region of the release element 7 pivoting the spring arm 17 radially outwards is designed to be larger in the radial direction with respect to the axis of symmetry 54 than the region of the release element 7 interacting simultaneously with the spring arm 16.Also in the embodiment of the device 1 according to FIG. 16, the piston unit 4 and the latching device 6 are to be mounted in a rotationally fixed manner with respect to one another to the same extent as the device 1 according to FIGS. 12 and 14, in order to be able to ensure the mode of operation of the device 1 to the desired extent.In all embodiments of the device 1, with the electromagnet 15 energized and at the same time the operating state of the device 1 without pressure, a so-called wash line function is provided via the device 1, with the aid of which wash line function the parking lock device 2 is held to the desired extent reliably in the designed operating state when the motor is switched off and the corresponding electrical supply is supplied. In contrast to this, the parking lock device 2 is secured against incorrect deployment via the device 1 during an activated remote start function when the electromagnet 15 is not energized, since incorrect printing on the piston unit 4 and an associated axial adjustment of the piston unit 4 by the latching device 5 when the electromagnet 15 is not energized are reliably effectively prevented.Reference numerals denote reference numerals1 Device 2 Parking lock device 3 Cylinder 4 Piston unit 5 Locking device 6 Actuating device 7 Release element, locking cone 8 Armature rod 9 Armature element 11 Spring device 12 Component 13 Parking lock valve 14 Effective surface 15 Electromagnet 16, 16A, 16B Spring arm, locking pawl 17, 17A, 17B Spring arm, Detent pawl 18 Detent region 19 Detent groove 20 Sleeve region 21 Region of the spring arm 16 22 Conical region 23 Cylindrical surface region 24 Inner locking section 25 Conical region of the inner locking section 24 26 Further detent region 27 Cylindrical region of the locking section 24 28 Annular disk-shaped region of the locking section 24 29 Sliding element 30 Spring device 31 Spring ring 32 Inner groove 33 Detent disk 34 Elongated hole of the piston unit 35 Bolt 36 Stop 37 Coupling point 38 Parking lock rod 39 Parking lock cone 40 Parking lock pawl 41 Parking lock wheel 42 Compression spring 43 Stop 44 Emergency release 45 Cable 46 Lever region 47 Further coupling point 48 Further stop 49 Projecting region of the spring arm 17 50 Detent region of the spring arm 16 51 Detent region of the spring arm 17 52, 53 Detent region of the piston unit 4 54 Axis of symmetry of the device 1 p Actuation pressure p_sys System pressure t Groove depth S Closing device

Claims

Device (1) for actuating a locking mechanism (2), in particular for actuating a parking lock device of a drive train of a vehicle which is designed with an automatic transmission, which has at least one piston unit (4) which is sprung in the closing direction (S) of the locking mechanism (2) and can be actuated hydraulically in the opening direction of the locking mechanism (2), a latching device (5) for holding the piston unit (4) at least in axial positions which are equivalent to the open and to the closed state of the locking mechanism (2), and an actuating device (6) having an electromagnet (15) for actuating a release element (7) which can be acted upon with an electromagnetic-side actuating force for switching the latching device (5) between an operating state holding the piston unit (4) and an operating state releasing the piston unit (4), wherein the plunger unit (4) is held by the latching device (5) in its position equivalent to the closed state of the locking mechanism (2) in the non-energized operating state of the electromagnet (15), characterized in that the latching device (5) is designed with at least one spring arm (16, 17) which can be brought into operative connection with the plunger unit (4) both in the axial position of the plunger unit (4) which is equivalent to the open and to the closed state of the locking mechanism (2), by means of which spring arm the plunger unit (4) can be held in the axial position which is equivalent to the open and to the closed state of the locking mechanism (2).Device according to claim 1, characterised in that the plunger unit (4) is held by the latching device (5) in its position equivalent to the open state of the locking mechanism (2) in the energized operating state of the electromagnet (15).Device according to claim 2, characterised in that the spring arm (16, 17) is designed with a spring force prestress which, at least in the axial position equivalent to the open state of the locking mechanism (2), swivels the spring arm (16, 17) into its position locking the piston unit (4), wherein the spring arm (16, 17) is firmly connected to the actuating device (6) with its end facing away from the piston unit (4), so that the spring force prestress of the spring arm (16, 17) can be supported on the latter.Device according to claim 3, characterised in that the spring arm (16, 17) is guided by the spring bias into engagement with the piston unit (4) to the operating state of the spring arm (16, 17) to which the piston unit (4) is held by the spring arm (16, 17) in the axial position equivalent to the open state of the locking mechanism (2).Device according to claim 3 or 4, characterised in that the spring arm (16, 17) is guided by the release element (7) against the spring bias into engagement with the piston unit (4) to the operating state of the spring arm (16, 17) to which the piston unit (4) is held by the spring arm (16, 17) in the axial position equivalent to the closed state of the locking mechanism (2).Device according to one of Claims 2 to 5, characterized in that the spring arm (16, 17) is surrounded at least in regions in the radial direction by a sleeve region (20) of the piston unit (4) which can be displaced with the piston unit (4) in the axial direction with respect to the spring arm (16, 17), wherein the spring arm (16, 17) can be guided by the release element (7) with a latching region (18) in the axial position of the piston unit (4) which is equivalent to the closed state of the locking mechanism (2) into a latching groove (19) arranged in an inner radius region of the sleeve region (20).Device according to claim 6, characterised in that the inner radius of the inner radius region of the sleeve region (20) is smaller than an inner radius of an inner radius region of the sleeve region (20), which surrounds an inner blocking section (24) of the piston unit (4) which can be overlapped by the spring arm (16, 17) in the axial position of the piston unit (4) equivalent to the open state of the locking mechanism (2).Device according to claim 6 or 7, characterised in that a surface of the release element (7) facing the spring arm (16, 17) is matched to a surface of the spring arm (16, 17) facing the release element (7) and an inner side of the sleeve region (20) is matched to an outer side of the spring arm (16, 17) facing the sleeve region (20), so that a pivoting movement of the spring arm (16, 17) in the direction of the blocking section (24) of the piston unit (4) is released by the release element (7) in the energized state of the electromagnet (15) and the spring arm (16, 17) can be guided out of the engagement of the blocking section (24) by the release element (7) in the non-energized state of the electromagnet (15).Device according to claim 8, characterised in that the surface of the release element (7) facing the spring arm (16, 17) is matched to the surface of the spring arm (16, 17) facing the release element (7) and the inside of the sleeve region (20) is matched to the outside of the spring arm (16, 17) facing the sleeve region (20), so that a pivoting movement of the spring arm (16, 17) in the direction of the sleeve region (20) of the piston unit (4) is enforced by the release element (7) in the non-energized state of the electromagnet (15) and a pivoting movement of the spring arm (16, 17), which leads the spring arm (16, 17) out of the engagement with the latching groove (19), is enabled by the release element (7) in the energized state of the electromagnet (15).Device according to one of Claims 2 to 9, characterized in that the latching device (5) is formed with at least two spring arms (16, 17), it being possible for the piston unit (4) to be locked in its axial position which is equivalent to the open state of the locking mechanism (2) by means of one of the spring arms (17) in the energized state of the electromagnet (15), while the piston unit (4) can be held by the other spring arm (16) in its axial position which is equivalent to the closed state of the locking mechanism (2) in the non-energized state of the electromagnet (15).Device according to claim 10, characterised in that the spring arms (16, 17) are of identical design and cooperate with a rotationally symmetrical release element (7), wherein the spring arms (16, 17) are mounted offset relative to one another in the axial direction with respect to the release element (7) and, depending on the axial position of the piston unit (4) and the release element (7) relative to one another, are alternately in locking engagement with the piston unit (4) or can be guided by the release element (7) out of engagement with the piston unit (4).Device according to claim 10, characterised in that the spring arms (16, 17) are of identical design and cooperate with a non-rotationally symmetrical release element (7), wherein the spring arms (16, 17) are mounted at the same height in the axial direction with respect to the release element (7) and, depending on the axial position of the piston unit (4) and the release element (7) with respect to one another, are alternately in locking engagement with the piston unit (4) or can be guided by the release element (7) out of engagement with the piston unit (4).Device according to one of Claims 10 to 12, characterized in that the piston unit (4) is formed with latching regions (52, 53) which are arranged offset with respect to one another in the axial direction and which interact with the spring arms (16, 17) in each case as a function of a position of the release element (7) which is dependent on the operating state of the electromagnet (15), in a circumference which locks the piston unit (4) or are disengaged from the spring arms (16, 17).Device according to one of Claims 10 to 13, characterized in that the piston unit (4) is connected to a ratchet disc (33), which can be set in rotation as a function of an axial adjustment of the piston unit (4) and which can be brought into operative connection with the locking mechanism (2) via a parking lock rod (38), it being possible to produce a manually triggerable relative movement between the ratchet disc (33) and the piston unit (4), by means of which the locking mechanism (2) can be transferred manually from its closed operating state into its open operating state independently of a current operating state of the piston unit (4).

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