System for actuating a parking lock

Abstract

The invention relates to a system for actuating a parking lock (10) in a drive train of a motor vehicle, with an electric machine (14) which is drive-connected via a drive shaft (16) to a pump (12) and, in a first operating state of a first rotational direction of a drive shaft of the electric machine (14), the pump (12) for the hydraulic system of the drive train is operated for the supply of coolant and lubricant, and wherein the pump shaft (18) is connected via a freewheel (22) with an adjusting actuator system (30) as transmission stage to the parking lock (10), wherein the parking lock (10) can be actuated in a manner which is dependent on a rotary angle of a parking lock shaft (44) into a first functional position, in which the parking lock (10) is not actuated, and a second functional position, in which the parking lock (10) is activated, wherein, in the case of a request for actuating the parking lock (10) in a second operating state, the drive shaft (16) of the electric machine (14) is operated with a second rotational direction, with the result that the adjustment actuator system (30) is coupled via the freewheel (22) to the pump shaft (18) and is activated, and wherein the rotational movement of the electric machine (14) is converted by means of the adjustment actuator system (30) in a positively guided manner into an alternatingly rotational movement of the parking lock shaft (44) in order to set the first and second functional position.

Description

[0001] System for operating a parking lock

[0002] The invention relates to a system for actuating a parking lock.

[0003] State of the art

[0004] In highly integrated electric drive systems of vehicles, oil management is of crucial importance, since on the one hand the lubrication of all required components must be covered, and on the other hand the lubricating and cooling medium as well as the cooling of the active components are increasingly coming into focus.

[0005] Conventional mechanical oil pumps, integrated into the intermediate shaft for cost reasons, have the disadvantage of a fixed delivery volume dependent on the engine speed. However, especially at standstill or in the lowest engine speed range, the mechanical pump is no longer sufficient due to the ever-increasing performance requirements, e.g., due to additional functions such as hill hold or hill start situations. It cannot provide sufficient or even insufficient lubricant and cooling medium for cooling at the lowest engine speeds.

[0006] 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.

[0007] Such parking locks, for example, have a parking lock gear connected to a transmission output shaft, with a pawl connected to the housing engaging its teeth to establish a parking lock position. The parking lock assembly can be actuated manually via a selector lever and a connected cable or linkage, or by means of a parking lock actuator. Actuation of a parking lock assembly by a parking lock actuator is also referred to as "park by wire."

[0008] 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 achieved by an electrical adjustment.

[0009] DE 10 2016 210 757 B3 shows a parking brake actuated by an electric motor. An eccentric component is rotated in one direction. A freewheel may also be provided.

[0010] In systems with electric oil pumps, the respective subsystems, such as the parking lock described above, are usually designed separately, so that a separate cooling circuit with an additional actuator path leads to increased component complexity.

[0011] DE 10 2016 109 553 A1 discloses a hydraulic actuation system, 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 assigned to the pumping device via a switchable clutch device in such a way that, when the clutch device is engaged, 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 driven at least indirectly by the pump drive elements. The actuator for mechanically actuating the parking lock can be controlled solely by closing or opening the clutch 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.

[0012] DE 10 2019 201 664 B4 shows a system for actuating a parking lock in a transmission with an electric machine which is connected via at least one freewheel to a pump for the hydraulic system of the transmission and to an eccentric arrangement, wherein the eccentric arrangement engages and disengages a parking lock.

[0013] By combining two tasks in one electric drive, it is used more efficiently and an additional electric motor for actuating a parking lock is eliminated.

[0014] Further systems for actuating a parking lock in a transmission with an electric machine are known from DE 10 2019 214 131 A1 and DE 10 2020 203 462 A1.

[0015] DE 10 2020 203452 A1 discloses a system for actuating a parking lock with a stationary and pivoting parking lock pawl. The parking lock pawl is actuated by a control contour of a control cam.

[0016] 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.

[0017] This problem is solved by the features of claim 1.

[0018] Furthermore, the object is achieved by the features of claim 7. The system for actuating a parking lock in a drive train of a motor vehicle comprises an electric machine which is drivingly connected to a pump via a drive shaft and, in a first operating state of a first direction of rotation of a drive shaft of the electric machine, operates the pump for the hydraulic system of the drive train to supply coolant and lubricant, 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 depending on a rotation angle of a parking lock shaft into a first functional position in which the parking lock is not activated and a second functional position in which the parking lock is activated,wherein, upon request to actuate the parking lock in a second operating state, the drive shaft of the electric machine is operated in a second direction of rotation, so that the adjustment actuator is coupled and activated with the pump shaft via the freewheel, and wherein the adjustment actuator converts the rotary movement of the electric machine into an alternating rotary movement of the parking lock shaft for setting the first and second functional positions.

[0019] The aim is, for example, for primary units with a parking lock to operate the electric machine as an actuator motor in a dual function, since both operating states can be operated separately, namely the parking lock when the vehicle is parked and the oil supply when the system is active.

[0020] This means that in a first operating state, a first direction of rotation of the drive shaft of the electric machine, the oil pump is operated in pumping mode with a pressure and volume flow to generate an oil circuit, and the adjustment actuator for actuating the parking lock is decoupled via a freewheel and blocked with regard to adjustment. In a second operating state, a second direction of rotation of the drive shaft, the pump is operated in suction mode, wherein the parking lock is coupled to the pump shaft via the freewheel and the locking of the adjustment actuator is released, and a uniform rotary movement of the drive shaft or pump shaft is converted into a rotary movement of the parking lock shaft that changes the direction of rotation via the adjustment actuator in such a way that in a first angle of rotation range of the drive shaft orPump shaft 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 a second direction of rotation of the parking lock shaft and a release of the locking of the parking lock is achieved.

[0021] The solution according to the invention allows a pumping operation in a first operating state by a simple reversal of the direction of rotation of the drive shaft of the electric machine and in a second operating state both a locking of the parking lock and a release of the locking of the parking lock by means of an adjustment actuator.

[0022] The adjustment actuator is arranged as a transmission stage for converting the uniform rotary movement of the pump shaft into a rotary movement that changes the direction of rotation between the pump shaft or drive shaft of the electric machine and the parking lock shaft.

[0023] In the first operating state of the electric motor, the adjustment actuator is locked and decoupled from the pump shaft via a freewheel. In the second operating state of the electric motor, the adjustment actuator is released and rotationally fixedly coupled to the pump shaft via the freewheel.

[0024] According to the invention, the adjustment actuator comprises a crank drive with a connecting rod or with a link control.

[0025] The invention is described in more detail below with reference to the drawings and various embodiments. It shows:

[0026] Figure 1 shows an embodiment of a parking lock actuation in a cross section,

[0027] Figure 2 is a side view of the adjustment actuator of Figure 1,

[0028] Figure 3 a side view of the complete parking lock actuation according to

[0029] Figure 1 ,

[0030] Figure 4 shows a cross-section of the parking lock actuation in the area of ​​the adjustment actuator according to Figure 1,

[0031] Figures 5a-5d show the adjustment actuators in a side view in four different functional positions for the actuation of the parking lock; and

[0032] Figures 6a-6d show a further embodiment of the adjustment actuator in a side view in four different functional positions for actuating the parking lock.

[0033] 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 drive-coupled to the pump impeller 20 of the pump 12 via the drive shaft 16.

[0034] 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.

[0035] 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.

[0036] In the first operating state of the electric motor 14, the pump 12 is operated in normal pumping mode. In this operating state, the variable displacement actuator 30 is not operated; it is decoupled from the pump shaft 18 and the electric motor 14 by the freewheel 22. At the same time, the variable displacement actuator 30 is blocked by a locking device 32.

[0037] As soon as a request for actuation of the parking lock 10 is received, the direction of rotation of the electric motor 14 is reversed. In this second operating state of the electric motor 14, the adjustment actuator 30 is non-rotatably coupled to the pump shaft 18 via the freewheel 22 and activated. To activate the adjustment actuator 30, the locking mechanism 32 is released.

[0038] When switching to the second operating state of the electric motor 14, the pump 12 briefly sucks instead of pumping. This short-term state of the pump 12 is not relevant for the cooling and lubrication circuit. A short-term interruption for the actuation of the parking lock 10 does not have a critical effect on the hydraulic system.

[0039] The parking lock 10 is generally known to those skilled in the art in terms of its design and function. The parking lock 10 essentially comprises a pivotably mounted parking lock pawl 40 fixed to the housing, a parking lock gear 42, a parking lock shaft 44, and an actuating cam 46 fixedly mounted on the parking lock shaft 44. Furthermore, the parking lock 10 typically comprises a mechanical spring 45, which is spring-loaded and arranged between the parking lock shaft 44 and the actuating cam 46.

[0040] The parking lock 10 has two functional positions. The first functional position is the release position, in which the parking lock is not activated. The second functional position is the park position, in which the parking lock is activated.

[0041] In the first functional position, the parking lock pawl 40 does not engage the teeth of the parking lock gear 42. In the second functional position, the parking lock pawl engages the teeth of the parking lock gear 42. The parking lock is activated. This then rotationally locks the parking lock gear 42 and elements connected to it, such as the shafts of a drive train. The actuation of the parking lock pawl 40 and, consequently, the actuation of the parking lock, takes place via the actuating cam 46 and the aforementioned mechanical spring 45. Upon rotation of the parking lock shaft 44 in a first direction of rotation by a rotation angle -α and an opposite second direction of rotation by a rotation angle +α, the contour of the actuating cam 46 controls a pivoting movement of the parking lock pawl 40 into the first or second functional position.

[0042] The angle of rotation + / -a and thus the position of the parking lock shaft 44 is detected by a position sensor 48.

[0043] 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 equally of the pump shaft by the adjustment actuator 30.

[0044] The kinematic translation of these above-mentioned movements of the pump shaft and parking lock shaft 44 is achieved via the adjustment kinematics 30, which is shown in a first embodiment in Figures 1 - 5d.

[0045] The adjustment kinematics 30 is designed as a crank drive, comprising a toothed disk 50 which meshes via a toothing with the pinion of an output shaft of a housing section of the freewheel 22. The toothed disk 50 is connected to a shaft in a rotationally fixed manner. The toothed disk 50 has an axially projecting pin 51 at a radially outer position, i.e. spaced from the central axis. This pin 51 slideably engages in a slotted guide 52 of a control disk 54. The control disk 54 is connected to the parking lock shaft 44 in a rotationally fixed manner. The slotted guide 54 is introduced in the form of a linear groove 55 in a control arm 56 which is connected eccentrically to the control disk 54. In a further embodiment not shown, the groove can also have a different shape in order to achieve a different advantageous transmission ratio.As can be seen particularly from Figures 5b-5d, the control disc 54 is locked in the corresponding position by the locking device 32. The control disc 54 has corresponding recesses on its outer circumference, into which a spring-loaded plunger engages in a locking manner. Alternatively, the locking can also occur at another location along the entire path of the adjustment actuator. Accordingly, locking and deactivation of the adjustment actuator can also occur on or at the parking lock shaft 44 or on or at the toothed disk 50.

[0046] Figures 5a - 5d show the different positions of the parking lock shaft 44 during a complete rotation of the toothed disk 50 by 360 degrees.

[0047] Figure 5a corresponds to a rotation of the toothed disk 50 by 0 degrees. The parking lock shaft has a rotation angle of 0 degrees. In this situation, pin 51 is at the radially inner stop of the groove 55 of the guide 52.

[0048] When the toothed disk 50 rotates 90 degrees in the direction of rotation shown in Figure 5b, the pin 51 is forced accordingly via the guideway and translated into a rotation of the parking lock shaft 44 by a rotation angle +a. This position of the parking lock shaft 44 corresponds to the second functional position, in which the parking lock 10 is activated.

[0049] With a further rotation of the toothed disk 50 by 90 degrees = a total of 180 degrees as shown in Figure 5c, the pin 51 rests against the radially outer stop of the groove of the link guide and the parking lock shaft 44 pivots in a forced manner back into the situation of Figure 5a, angle of rotation 0 degrees.

[0050] Upon a further rotation of the toothed disk 50 by 90 degrees = a total of 270 degrees of rotation of the toothed disk 50 as shown in Figure 5d, the pin 51 is forced accordingly via the slotted guide and translated into a rotation of the parking lock shaft 44 by a rotation angle -a. This position of the parking lock shaft 44 corresponds to the first functional position in which the parking lock 10 is not activated. Figures 6a - 6d show a further embodiment of an adjustment kinematics.

[0051] 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 toothing.

[0052] 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 transmitting a torque.

[0053] The toothed pulley 71 is connected to a shaft in a rotationally fixed manner.

[0054] 71 is connected in an articulated manner to a first end of a connecting rod 72 at a radially outer position, ie spaced from the central axis.

[0055] A radially outwardly 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.

[0056] As can be seen from Figures 6a - 6d, with a uniform rotation of the toothed disk 71, the uniform rotation is converted into an alternating rotary movement via the crank mechanism or the connection of the connecting rod 72 to the control lever 74.

[0057] Figure 6a corresponds to a rotation of the toothed disk 71 by 0 degrees. The parking lock shaft, and accordingly 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 disk 71.

[0058] When the toothed disk 71 rotates 90 degrees in the direction of rotation shown in Figure 6b, the first end of the connecting rod 72 is forced to rotate 90 degrees into a 9 o'clock position, thus displacing the control lever 74 by a rotation angle -a. This position of the parking lock shaft 44 corresponds to the second functional position, in which the parking lock is activated.

[0059] With a further rotation of the toothed disk 71 by 90 degrees = a total of 180 degrees as shown in Figure 6c, the first end of the connecting rod 72 is in the 6 o'clock position and the parking lock shaft 44 pivots back into the situation of Figure 6a, angle of rotation 0 degrees.

[0060] Upon a further rotation of the toothed disk 71 by 90 degrees = a total of 270 degrees of rotation of the toothed disk as shown in Figure 6d, the first end of the connecting rod 72 is forced to rotate by a further 90 degrees into a 3 o'clock position, thus displacing the control lever 74 by a rotation angle of +a. This position of the parking lock shaft 44 corresponds to the first functional position in which the parking lock is not activated.

[0061] List of reference symbols

[0062] 10 Parking lock

[0063] 12 Pump

[0064] 14 electric machine

[0065] 16 Drive shaft

[0066] 18 Pump shaft

[0067] 20 Pump impeller

[0068] 22 Freewheel

[0069] 24 Output shaft / pinion

[0070] 30 Adjustment actuators

[0071] 32 Locking

[0072] 40 Parking lock pawl

[0073] 42 Parking lock gear

[0074] 44 Parking lock shaft

[0075] 45 mechanical spring

[0076] 46 Actuating cam

[0077] 48 Position sensor

[0078] 50 toothed disc

[0079] 51 pins

[0080] 52 Scenery guide

[0081] 54 control disc

[0082] 55 groove

[0083] 56 Control arm

[0084] 70 Adjustment kinematics toothed disc connecting rod control lever

Claims

Claims 1. A 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 to the parking lock (10) as a transmission stage, 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 in 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 in 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 via a toothing with a pinion of an output shaft of a housing section of the freewheel (22),and that the toothed disc (50) has an axially projecting pin (51) at a radially outer position, ie spaced from the center axis of the toothed disc (50), and that the pin (51) slides into the cogwheel, guide (52), wherein the slotted guide (52) is arranged eccentrically on a control disc (54), and that the control disc (54) is connected in a rotationally fixed manner to the parking lock shaft (44).

2. System for actuating a parking lock (10) according to claim 1, characterized in that 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 rotational 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 rotational 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 in that the control disc (54) comprises an eccentrically connected control arm (56) and the slotted guide (54) is introduced as a groove (55) in the control arm (56).

4. System for actuating a parking lock (10) according to claim 3, characterized in that the groove (55) is rectilinear.

5. System for actuating a parking lock (10) according to one of the preceding claims, characterized in that 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 in that the locking device (32) is designed as a spring-biased plunger which, in the blocked state of the adjustment actuator (30), engages in a recess on the control disc (54). 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 to the parking lock (10) as a transmission stage, 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 in 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 positively guided manner into an alternating rotary movement of the parking lock shaft (44) for setting the first and second functional positions, characterized in that 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 articulated to the toothed disk (71) at a radially outer position, ie spaced from the central axis, and that the adjusting 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, The end of the connecting rod (72) is articulated to a radially outer end region of the control lever (74).

8. System for actuating a parking lock (10) according to one of the preceding claims, characterized in 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 in 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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