System for operating a parking lock

Abstract

The invention relates to a system for actuating a parking lock (10) in a drive train of a motor vehicle, comprising an electric machine (14) which is driven by a drive shaft (16) and which, in a first operating state of a first direction of rotation of a drive shaft of the electric machine (14), operates the pump (12) for the hydraulic system of the drive train to supply coolant and lubricant, and wherein the pump shaft (18) is connected to the parking lock (10) via a freewheel (22) with an adjusting actuator (30) as a transmission stage, wherein the parking lock (10) can be actuated, depending on a rotation angle of a parking lock shaft (44), into a first operating position in which the parking lock (10) is not activated and a second operating position in which the parking lock (10) is activated.wherein, when the parking lock (10) is required to be actuated in a second operating state, the drive shaft (16) of the electric machine (14) is operated in a second direction of rotation, so that the adjusting actuator (30) is coupled to and activated by the freewheel (22) with the pump shaft (18), and wherein, by means of the adjusting actuator (30), the rotary motion of the electric machine (14) is positively converted into an alternating rotary motion of the parking lock shaft (44) for setting the first and second operating positions.

Description

[0001] The invention relates to a system for operating a parking lock. State of the art

[0002] In highly integrated electric drive systems of vehicles, oil management is of crucial importance, as on the one hand the lubrication of all required components must be covered, and on the other hand the lubricating and cooling medium is increasingly coming into focus with regard to the cooling of the active components.

[0003] Mechanical oil pumps, commonly integrated into the intermediate shaft for cost reasons, have the disadvantage of a fixed delivery volume that varies with engine speed. Especially at standstill or in the lowest engine speed range, however, the mechanical pump is no longer sufficient due to ever-increasing performance demands, for example, from additional functions such as hill-hold or hill-start situations, as it cannot provide sufficient lubrication and cooling fluid at very low engine speeds.

[0004] In motor vehicle drive systems with an internal combustion engine and automatic transmission, as well as in motor vehicle drive systems with an electric machine (electric or hybrid drive), parking locks are still used to prevent the motor vehicle from rolling away unintentionally at any time and in any place.

[0005] Such parking locks feature, for example, a parking lock wheel connected to a transmission output shaft. A pawl connected to the housing engages in the teeth of this wheel to establish a parking lock position. The parking lock mechanism can be actuated manually via a selector lever and an associated cable or linkage, or by means of a parking lock actuator. Actuation of a parking lock mechanism by a parking lock actuator is also referred to as "park by wire."

[0006] Parking locks of this type are known, for example, from EP 3 067 591 B1. This parking lock has a locking actuator that is coupled to an actuating element via a lever arrangement. Actuation is effected by an electric adjuster.

[0007] German patent DE 10 2016 210 757 B3 discloses a parking brake with actuation via an electric motor. An eccentric component is rotated in one direction. A freewheel may also be provided.

[0008] Typically, in systems with electric oil pumps, the respective subsystems, such as the previously described parking lock, are designed separately, so that a separate cooling circuit with an additional actuator path leads to an increased number of components.

[0009] From DE 10 2016 109 553 A1, a hydraulic actuation system is known, wherein the actuator has a mechanically acting actuating mechanism and can be coupled, at least indirectly, to the pumping device or to the pump drive elements associated with the pumping device via a switchable coupling device such that, with the coupling device closed, the parking lock can be moved from the released position to the locked position and / or from the locked position to the released position by means of the mechanically acting actuating mechanism and at least indirectly by the pump drive elements. The actuator for the mechanical actuation of the parking lock can be controlled solely by closing or opening the coupling device.A complex piping architecture and hydraulic control elements for controlling a hydraulic actuator, as well as the actuator itself, can be eliminated, and the requirements for the hydraulic pressure performance of the pumping device are reduced.

[0010] DE 10 2019 201 664 B4 discloses a system for actuating a parking lock in a gearbox with an electric machine, which is connected via at least one freewheel to a pump for the hydraulic system of the gearbox and to an eccentric arrangement, wherein the eccentric arrangement engages and disengages a parking lock.

[0011] By combining two tasks on one electric drive, it is used more efficiently and a further electric motor for actuating a parking lock is no longer needed.

[0012] Further systems for actuating a parking lock in a gearbox with an electric machine are known from DE 10 2019 214 131 A1 and DE 10 2020 203 462 A1.

[0013] German patent DE 10 2020 203 452 A1 discloses a system for operating a parking lock with a fixed and pivoting parking lock latch. The parking lock latch is actuated by a control contour of a control cam.

[0014] The object of the invention is to improve a system known from the prior art for actuating a parking lock for a drive train of a motor vehicle.

[0015] This problem is solved by the features of claim 1. Furthermore, the problem is solved by the features of claim 7.

[0016] The system for actuating a parking lock in the drivetrain of a motor vehicle comprises an electric machine which is driven by a drive shaft to a pump and, in a first operating state, operates the pump for the hydraulic system of the drivetrain for the supply of coolant and lubricant in a first direction of rotation of a drive shaft of the electric machine, and wherein the pump shaft is connected to the parking lock via a freewheel with an adjusting actuator as a transmission stage, wherein the parking lock can be actuated into a first operating position in which the parking lock is not activated and a second operating position in which the parking lock is activated, depending on a rotation angle of a parking lock shaft, and wherein, when actuating the parking lock is required in a second operating state, the drive shaft of the electric machine is operated in a second direction of rotation.so that the adjusting actuator is coupled to and activated by the freewheel with the pump shaft, and wherein the rotary motion of the electric machine is positively converted by means of the adjusting actuator into an alternating rotary motion of the parking lock shaft for setting the first and second operating positions.

[0017] The aim is, for example, to operate the electric machine as an actuator motor in a dual function for primary units with a parking lock, since both operating states can be controlled separately, namely the parking lock when the vehicle is parked and the oil supply when the system is active.

[0018] This means that in a first operating state, with the drive shaft of the electric machine rotating in a first direction, the oil pump is operated in pump mode to generate an oil circuit with a pressure and flow rate, and the adjusting actuator for actuating the parking lock is decoupled via a freewheel and blocked with respect to adjustment. In a second operating state, with the drive shaft rotating in a second direction, the pump is operated in suction mode, whereby the parking lock is coupled to the pump shaft via the freewheel and the locking mechanism of the adjusting actuator is released, and the adjusting actuator converts a uniform rotary motion of the drive shaft or the pump shaft into a rotary motion of the parking lock shaft that changes the direction of rotation, such that in a first rotational angular range of the drive shaft or the pump shaft, the parking lock is fully engaged.The pump shaft achieves a first direction of rotation of the parking lock shaft and a locking of the parking lock, and in a second rotation angle range of the drive shaft achieves a second direction of rotation of the parking lock shaft and a release of the locking of the parking lock.

[0019] The solution according to the invention allows, by simply reversing the direction of rotation of the drive shaft of the electric machine, a pumping operation in a first operating state and, in a second operating state, both locking and releasing the parking lock by means of an adjusting actuator.

[0020] The adjustment actuator is arranged as a translation stage to convert the uniform rotary motion of the pump shaft into a rotary motion that changes the direction of rotation between the pump shaft or drive shaft of the electric machine and the parking lock shaft.

[0021] In the first operating state of the electric machine, the adjustment actuator is latched and decoupled from the pump shaft via a freewheel. In the second operating state of the electric machine, the adjustment actuator is released and rotationally fixed to the pump shaft via the freewheel.

[0022] According to the invention, the adjustment actuator comprises a crank drive with connecting rod or with a cam control.

[0023] The invention is described in more detail below with reference to the drawings and in different embodiments.

[0024] It shows: Fig. 1 an embodiment of a parking lock actuation in a cross-section, Fig. 2 a side view of the adjustment actuator of the Fig. 1, Fig. 3 a side view of the complete parking lock operation according to Fig. 1, Fig. 4 a cross-section of the parking lock actuation in the area of ​​the adjustment actuator according to Fig. 1, Fig. 5a-5d the adjusting actuator in a side view in four different functional positions of the parking lock operation; and Fig. 6a-6d shows another embodiment of the adjustment actuator in a side view in four different functional positions of the actuation of the parking lock.

[0025] Fig. Figure 1 shows a system for actuating a parking lock 10. This system for actuating the parking lock 10 comprises a pump 12 with a pump shaft 18 and a pump impeller 20, as well as an electric machine 14 with a drive shaft 16. The electric machine 14 is coupled to the pump impeller 20 of the pump 12 via the drive shaft 16.

[0026] In a first direction of rotation, the electric machine actuates the pump 12 in pump operation to generate a volume flow to provide cooling and lubrication in the drive train of the motor vehicle.

[0027] The pump shaft 18 can be coupled to an adjustment actuator 30 via a freewheel 22. The adjustment actuator 30 is designed to actuate the parking lock 10, as described in more detail below.

[0028] In the first operating state of the electric machine 14, the pump 12 is operated in normal pumping mode. In this operating state, the adjusting actuator 30 is not operated; it is decoupled from the pump shaft 18 and the electric machine 14 by the freewheel 22. At the same time, the adjusting actuator 30 is blocked by a locking device 32.

[0029] As soon as a request is made to actuate the parking lock 10, the direction of rotation of the electric machine 14 is reversed. In this second operating state of the electric machine 14, the adjustment actuator 30 is coupled to the pump shaft 18 via the freewheel 22 and activated. To activate the adjustment actuator 30, the locking mechanism 32 is released.

[0030] When switching to the second operating state of the electric machine 14, the pump 12 briefly draws in fluid instead of pumping. This brief state of the pump 12 is not relevant for the cooling and lubrication circuit. A brief interruption for actuating the parking lock 10 does not critically affect the hydraulic system.

[0031] The design and function of the parking lock 10 are generally known to those skilled in the art. The parking lock 10 essentially comprises a pivotally mounted parking lock pawl 40 fixed to the housing, a parking lock wheel 42, a parking lock shaft 44, and an actuating cam 46 fixedly arranged on the parking lock shaft 44. Furthermore, the parking lock 10 typically includes a mechanical spring 45, which is spring-loaded and arranged between the parking lock shaft 44 and the actuating cam 46.

[0032] The parking lock 10 has two operating positions. The first operating position is the release position, in which the parking lock is not activated. The second operating position is the parking position, in which the parking lock is activated.

[0033] In the first operating position, the parking pawl 40 does not engage with the teeth of the parking wheel 42. In the second operating position, the parking pawl engages with the teeth of the parking wheel 42. The parking lock is activated. This then rotationally locks the parking wheel 42 and connected elements, for example, the shafts of a drive train.

[0034] The actuation of the parking lock pawl 40, and consequently the actuation of the parking lock, is effected via the actuating cam 46 and the aforementioned mechanical spring 45. When the parking lock shaft 44 rotates in a first direction of rotation by an angle of rotation -α and in an opposite second direction of rotation by an angle of rotation +α, the contour of the actuating cam 46 controls a pivoting movement of the parking lock pawl 40 into the first or second operating position.

[0035] The rotation angle + / -α and thus the position of the parking lock shaft 44 is detected via a position sensor 48.

[0036] The alternating rotational movement of the parking lock shaft 44 is achieved in the second operating position of the electric machine 14 in the second direction of rotation with a uniform rotation of the drive shaft and likewise of the pump shaft by the adjusting actuator 30.

[0037] The kinematic translation of these aforementioned movements of the pump shaft and parking lock shaft 44 is achieved via the adjusting kinematics 30, which in a first embodiment is located in the Fig. 1 - 5d shown.

[0038] The adjusting mechanism 30 is designed as a crank drive, which includes a toothed disc 50 that meshes with the pinion of an output shaft of a housing section of the freewheel 22 via a toothed connection. The toothed disc 50 is fixedly mounted on a shaft to prevent rotation. The toothed disc 50 has an axially projecting pin 51 at a radially outer position, i.e., spaced apart from the central axis. This pin 51 engages slidably in a cam guide 52 of a control disc 54. The control disc 54 is fixedly mounted on the parking lock shaft 44 to prevent rotation. The cam guide 54 is formed by a straight groove 55 in a control arm 56 that is eccentrically mounted on the control disc 54. In another embodiment not shown, the groove can also have a different shape to achieve a different advantageous transmission ratio.

[0039] As can be seen in particular from the Fig. As can be seen in Figures 5b-5d, the control disc 54 is locked in the corresponding position via the locking mechanism 32. The control disc 54 has corresponding recesses on its outer circumference into which a spring-loaded plunger engages. Alternatively, the locking mechanism can also be located at another point along the entire path of the adjustment actuator. Therefore, locking and deactivation of the adjustment actuator can also occur on or at the parking lock shaft 44 or on or at the toothed disc 50.

[0040] The Fig. Figures 5a - 5d show the different positions of the parking lock shaft 44 during a complete rotation of the toothed disc 50 by 360 degrees.

[0041] Fig. 5a corresponds to a rotation of the toothed disc 50 by 0 degrees. The parking lock shaft has a rotation angle of 0 degrees. In this situation, the pin 51 is at the radially inner stop of the groove 55 of the cam guide 52.

[0042] When the toothed disc 50 is rotated 90 degrees in the indicated direction of rotation, which is shown in the Fig. As shown in Figure 5b, pin 51 is positively guided via the cam guide and translated into a rotation of the parking lock shaft 44 by a twist angle +α. This position of the parking lock shaft 44 corresponds to the second operating position in which the parking lock 10 is activated.

[0043] With a further rotation of the toothed disc 50 by 90 degrees = a total of 180 degrees as shown in the illustration. Fig. 5c, pin 51 rests against the radially outer stop of the groove of the cam guide, and the parking lock shaft 44 pivots back into the position of Fig. 5a Rotation angle 0 degrees.

[0044] With a further rotation of the toothed disc 50 by 90 degrees = a total of 270 degrees rotation of the toothed disc 50 as shown in the illustration. Fig. In step 5d, pin 51 is positively guided via the cam guide and translated into a rotation of the parking lock shaft 44 by a twist angle -α. This position of the parking lock shaft 44 corresponds to the first functional position in which the parking lock 10 is not activated.

[0045] The Fig. Figures 6a-6d show a further embodiment of an adjustment kinematics 70 in the form of a crank drive. The adjustment kinematics 70 also has a toothed disk 71 which meshes with the pinion of an output shaft of a housing section of the freewheel 22 via a toothed connection.

[0046] In the second operating position of the electric machine, in which the two functional positions of the parking lock can be actuated, the output shaft is operatively coupled to the pump shaft via the housing section and the freewheel 22 for the transmission of a torque.

[0047] The toothed disc 71 is fixedly connected to a shaft in a rotationally fixed manner. A first end of a connecting rod 72 is pivotally connected to the toothed disc 71 at a radially outer position, i.e., spaced apart from the central axis.

[0048] A radially outward extending control lever 74 is fixedly connected to the parking lock shaft 44. The opposite second end of the connecting rod 72 is pivotally connected to a radially outer end region of the control lever 74.

[0049] As can be seen from the Fig. As can be seen in 6a - 6d, during a uniform rotation of the toothed disc 71, the uniform rotation is converted into an alternating rotary motion via the crank mechanism or the connection of the connecting rod 72 to the control lever 74.

[0050] Fig. 6a corresponds to a rotation of the toothed disc 71 by 0 degrees. The parking lock shaft, and consequently the control lever 74 shown, has a rotation angle of 0 degrees. In this situation, the first end of the connecting rod 72 is at the 12 o'clock position of the toothed disc 71.

[0051] When the toothed disc 71 is rotated 90 degrees in the indicated direction of rotation, which is shown in the Fig. As shown in Figure 6b, the first end of the connecting rod 72 is positively rotated by 90 degrees into a 9 o'clock position, thus displacing the control lever 74 by an angle of rotation -α. This position of the parking lock shaft 44 corresponds to the second operating position in which the parking lock is activated.

[0052] With a further rotation of the toothed disc 71 by 90 degrees = a total of 180 degrees as shown in the illustration. Fig. 6c the first end of the connecting rod 72 is in the 6 o'clock position and the parking lock shaft 44 is forcibly pivoted back into the position of Fig. 6a Rotation angle 0 degrees.

[0053] With a further rotation of the toothed disc 71 by 90 degrees = a total of 270 degrees rotation of the toothed disc as shown in the illustration. Fig. 6d The first end of the connecting rod 72 is forcibly rotated by a further 90 degrees into a 3 o'clock position, thus displacing the control lever 74 by a rotation angle of +α. This position of the parking lock shaft 44 corresponds to the first operating position in which the parking lock is not activated. List of reference symbols 10 Parking restrictions 12 Pump 14 electric machine 16 Drive shaft 18 Pump shaft 20 Pump impeller 22 Freewheel 24 Output shaft / pinion 30 Adjustment actuators 32 Locking mechanism 40 parking lock latch 42 Parking lock wheel 44 parking barrier wave 45 mechanical spring 46 Actuating cam 48 Position sensor 50 toothed disc 51 pin 52 Scenery guide 54 Control disc 55 Nut 56 Control arm 70 Adjustment kinematics 71 Toothed disc 72 Connecting rod 74 Control levers

Claims

[1] System for actuating a parking lock (10) in a drive train of a motor vehicle, comprising an electric machine (14) which is drivingly connected to a pump (12) via a drive shaft (16) and in a first operating state of a first direction of rotation of a drive shaft of the electric machine (14), the pump (12) for the hydraulic system of the drive train is operated to supply coolant and lubricant, and wherein a pump shaft (18) with an adjusting actuator (30) is connected as a transmission stage to the parking lock (10), wherein the parking lock (10) can be actuated as a function of a rotation angle of a parking lock shaft (44) into a first functional position in which the parking lock (10) is not activated and a second functional position in which the parking lock (10) is activated,wherein, upon request to actuate the parking lock (10) in a second operating state, the drive shaft (16) of the electric machine (14) is operated with a second direction of rotation, so that the adjustment actuator (30) is coupled and activated with the pump shaft (18), and wherein by means of the adjustment actuator (30) the rotary movement of the electric machine (14) is converted in a forced manner into an alternating rotary movement of the parking lock shaft (44) for setting the first and second functional positions, , characterized byin that the pump shaft (18) is connected to the adjustment actuator (30) via a freewheel (22), and in that the adjustment actuator (30) is designed as a crank drive with a slotted guide, wherein the slotted guide comprises a toothed disk (50) which meshes with a pinion of an output shaft of a housing section of the freewheel (22) via a toothing, and in that the toothed disk (50) has an axially projecting pin (51) at a radially outer position, i.e. spaced from the center axis of the toothed disk (50), and in that the pin (51) engages slidingly in the slotted guide (52), wherein the slotted guide (52) is arranged eccentrically on a control disk (54), and in that the control disk (54) is connected to the parking lock shaft (44) in a rotationally fixed manner. [2] System for actuating a parking lock (10) according to claim 1, characterized bythat the alternating rotary movement of the parking lock shaft (44) is implemented by means of the adjustment actuator (30) in such a way that in a first rotation angle range of the drive shaft (16) a first direction of rotation of the parking lock shaft (44) and a locking of the parking lock (10) is achieved and in a second rotation angle range of the drive shaft (16) a second opposite direction of rotation of the parking lock shaft (44) and a release of the locking of the parking lock (10) is achieved. [3] System for actuating a parking lock (10) according to claim 1, characterized by that the control disc (54) comprises an eccentrically connected control arm (56) and the slotted guide (54) is introduced into the control arm (56) as a groove (55). [4] System for actuating a parking lock (10) according to claim 3, characterized by that the groove (55) is straight. [5] System for actuating a parking lock (10) according to one of the preceding claims, characterized bythat the adjustment actuator (30) is blocked in the first operating state via a locking device (32). [6] System for actuating a parking lock (10) according to claim 5, characterized by that the locking device (32) is designed as a spring-loaded plunger which, when the adjustment actuator (30) is in the blocked state, engages in a recess on the control disc (54). [7] System for actuating a parking lock (10) in a drive train of a motor vehicle, comprising an electric machine (14) which is drivingly connected to a pump (12) via a drive shaft (16) and in a first operating state of a first direction of rotation of a drive shaft of the electric machine (14), the pump (12) for the hydraulic system of the drive train is operated to supply coolant and lubricant, and wherein a pump shaft (18) with an adjusting actuator (70) is connected as a transmission stage to the parking lock (10), wherein the parking lock (10) can be actuated as a function of a rotation angle of a parking lock shaft (44) into a first functional position in which the parking lock (10) is not activated and a second functional position in which the parking lock (10) is activated,wherein, upon request to actuate the parking lock (10) in a second operating state, the drive shaft (16) of the electric machine (14) is operated with a second direction of rotation, so that the adjustment actuator (70) is coupled and activated with the pump shaft (18), and wherein by means of the adjustment actuator (70) the rotary movement of the electric machine (14) is converted in a forcibly guided manner into an alternating rotary movement of the parking lock shaft (44) for setting the first and second functional positions, , characterized bythat the pump shaft (18) is connected to the adjustment actuator (70) via a freewheel (22), and that the adjustment actuator (70) is designed as a crank drive with a connecting rod, and that the adjustment actuator (70) as a crank drive with a connecting rod comprises a toothed disk (71) which meshes via a toothing with a pinion of an output shaft of a housing section of the freewheel (22), and that a first end of a connecting rod (72) is articulatedly connected to the toothed disk (71) at a radially outer position, i.e. spaced from the central axis, and that the adjustment actuator (70) further comprises a control lever (74) which is fixedly connected to the parking lock shaft (44) and which extends radially outwards from the parking lock shaft (44), and that the second end of the connecting rod (72) is connected to a radially outer end region of the Control lever (74) is articulated. [8] System for actuating a parking lock (10) according to one of the preceding claims, characterized by that the parking lock (10) comprises a stationary and pivotably mounted parking lock pawl (40) and a parking lock gear (42) designed with a toothing and connected to a transmission shaft, an actuating cam (46) arranged stationary on the parking lock shaft (44) and a spring (45), wherein the spring (45) is arranged in a spring-preloaded manner between the parking lock shaft (44) and the actuating cam (46). [9] System for actuating a parking lock (10) according to claim 8, characterized by that the alternating rotary movement of the parking lock shaft (44) in the second operating state causes the parking lock pawl (40) to pivot into the first and second functional positions via a control contour of the actuating cam (46).

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