Actuator system having an electric actuator motor and method for operating said actuator system

Abstract

The invention relates to an actuator system (1) having an electric actuator motor (2) that is connected on the drive side via a planet carrier (3a) of a planetary gear mechanism (3) which, on the output side, bears against an actuating gear (10) via a ring gear (3b) for mechanical actuation (7) and is connected via a sun gear (3d) and a freewheel (4) to an oil pump (5) and to a brake (6) arranged downstream of the oil pump (5).

Description

[0001] Actuator system with an electric actuator motor and method for operating the actuator system

[0002] The invention relates to an actuator system with an electric actuator motor which is connected on the drive side via a planet carrier of a planetary gear.

[0003] The invention also relates to a method for operating the actuator system.

[0004] State of the art

[0005] Electric drive axles often have electric actuator motors that operate functions such as parking lock, traction motor decoupling, or gear changes. These actuators are only needed for very short periods and remain unused for most of the operating time.

[0006] From DE 10 2020 201 758 A1, an actuator system is known with an electric actuator motor which is connected on the drive side via a planetary carrier of a planetary gearbox. The planetary gearbox of the actuator system is connected to an oil pump via a sun gear and a freewheel.

[0007] German patent application DE 10 2015 110 565 A1 discloses an electric drive for a vehicle comprising an electric motor and a planetary gear assembly including a sun gear. The sun gear is connected to a rotor of the electric motor.

[0008] The ring gear of the planetary gear assembly is connected to a brake that can be released.

[0009] Different functions, such as the parking lock and the electric oil pump, are typically operated by two separate actuators. The invention aims to eliminate one actuator and the associated control system. DE 10 2022 202 616 A1 discloses a parking lock actuation mechanism with an electric actuator that drives a pump for supplying coolant and lubricant via a common shaft. The pump shaft is mechanically separable from the parking lock, and the separation of the electric actuator motor from the parking lock mechanism is achieved at least via a coupling arrangement. Engaging and disengaging the parking lock is accomplished by reversing the direction of rotation of the actuator motor and by additional hydraulic or electrical actuation of the coupling arrangement.

[0010] The problem with using an electric actuator motor for different tasks in an electric drive system is that different volumes or different hydraulic pressures are required.

[0011] The object of the invention is to propose a device in which an actuator motor provides the necessary actuating forces and, during idle operating time, performs the function of an electric oil pump.

[0012] Description of the invention

[0013] The task is solved with an actuator system with an electric actuator motor, which is connected on the drive side via a planet carrier of a planetary gear, which on the output side is connected via a ring gear to an actuating wheel for mechanical actuation and is connected via a sun gear and a freewheel to an oil pump and a brake downstream of the oil pump, wherein the ring gear can be fixed via an end stop of the mechanical actuation.

[0014] The proposed actuator system reduces the number of actuator motors required when an electric oil pump is used in combination with a mechanical actuator. This also simplifies replacing a mechanical oil pump with an electric, demand-based oil pump if a mechanical actuator with an electric actuator motor is already in place.

[0015] The mechanical operation includes: a parking lock, a clutch, a gearshift.

[0016] While the parking lock is open, or an electric traction motor is connected to the drive wheels via a coupling, or a gear change is complete, the oil pump is driven by the same actuator motor via the planetary gear. This allows for an oil flow that can be controlled by the speed of the actuator motor.

[0017] The actuator motor rotates in two directions, with mechanical actuation being activated in the first direction.

[0018] In a second direction of rotation, the mechanical actuation is deactivated and the oil pump is driven.

[0019] Torque amplification is achieved from the actuator motor to the mechanical actuation via the planetary gear.

[0020] The problem is also solved by a method for actuating an actuator system, wherein, to activate the mechanical actuation, the actuator motor rotates in a first direction of rotation and drives the planet carrier of the planetary gear, wherein the output is via the ring gear to the actuating wheel and the sun gear of the planetary gear is locked in this first direction of rotation by the freewheel, with the brake being closed.

[0021] According to the invention, the oil pump is activated, the direction of rotation of the actuator motor is changed to the second direction of rotation in order to overcome the holding torque of the brake, and the planetary gear with its two outputs applies torque to the ring gear and the sun gear at both outputs, the ring gear being fixed via the end stop of the parking lock / clutch / shift mechanism, and as soon as the oil pump starts to rotate, oil pressure is built up and the brake is opened via a hydraulic connection.

[0022] The planetary gear increases the speed of the actuator motor through the summing circuit, thus operating the oil pump at a higher speed.

[0023] The advantages of the actuator system are that there is no drag loss of the oil pump during actuation and torque amplification from the actuator motor to the mechanical actuation by the planetary gear.

[0024] The drive actuator motor is connected via the transfer case to the parking lock / coupling / gear shift mechanism and additionally to an oil pump. The transfer case is a three-shaft planetary gearbox. In one direction of rotation, the output to the oil pump is blocked by a freewheel; in this state, power can only be transmitted from the actuator motor to the mechanical actuation. In the other direction of rotation, sufficient power is transmitted to the mechanical actuation via the brake. In this case, the parking lock is released or the traction motor is engaged. When the mechanical actuation reaches its end position / stop in this direction of rotation, sufficient torque can be sent to the oil pump to overcome the brake and build up oil pressure. The brake is then released hydraulically to minimize losses.The drive power of the actuator motor is now transferred to the oil pump as needed, until the parking brake is engaged again or the traction motor needs to be decoupled.

[0025] Description of the characters

[0026] Figure 1 shows an actuation system,

[0027] Figure 2 shows the actuation system with the parking lock activated in the first direction of rotation, Figure 3 shows the actuation system with the parking lock activated in the second direction of rotation,

[0028] Figure 4 shows the actuation system while the parking lock is being opened, Figure 5 shows the actuation system when the oil pump starts up, Figure 6 shows the actuation system with the oil pump running.

[0029] Figure 1 shows the structure of the inventive solution for an actuator system 1. An electric actuator motor 2 drives a planetary gear set 3. More precisely, the electric actuator motor 2 is connected to a planet carrier 3a. The planet carrier 3a carries planet gears 3c, which mesh with a ring gear 3b. A sun gear 3d serves as the output gear. The sun gear 3d is connected via a freewheel 4 to a pump 5 and a brake 6. The oil pump 5 has an oil inlet 8 and an oil outlet 9.

[0030] The ring gear 3b meshes with an actuating wheel 10, which is connected to a mechanical function such as a parking lock / clutch / shift 7.

[0031] The following figures, Figure 2 to Figure 6, show the functionality of actuator system 1 .

[0032] Figure 2 shows a change of status from an open parking lock to a closed parking lock or from an open coupling to a closed coupling.

[0033] The actuator motor 2 rotates in a first direction 11 and drives the planet carrier 3a of the planetary gear 3 to close the parking lock or the coupling. The output is via the ring gear 3b to the actuating wheel 10.

[0034] The sun gear 3d of the planetary gear 3 is locked in this first direction of rotation 11 by the freewheel 4, with the brake 6 engaged. This leads to direct power transmission towards the parking lock / clutch / shift mechanism 7 until an end stop 13 is reached.

[0035] This prevents drag losses in the oil pump 5 during actuation and torque amplification from the actuator motor 2 to the parking lock / clutch / shifter 7 through the planetary gear 3.

[0036] Figure 3 shows a change of status from a closed parking lock to an open parking lock or from a closed coupling to an open coupling.

[0037] The actuator motor 2 drives the planet carrier 3a in a second direction of rotation 12 to open the parking lock or the coupling. The output is again via the ring gear 3b of the planetary gear 3.

[0038] The sun gear 3d of the planetary gear 3 is locked in this direction of rotation by the brake 6, while the freewheel 4 is open. This leads to direct power transmission towards the parking lock / clutch / shift mechanism 7 until the end stop 13 is reached.

[0039] Figure 4 shows a situation when the actuation from a closed parking lock to an open parking lock or from an open clutch to a closed clutch is completed and end stop 13 is reached.

[0040] The ring gear 3b can no longer rotate in this direction. In this situation, no power transmission occurs because the actuator motor 2 compensates for the braking effect of the brake 6.

[0041] Figure 5 shows the power flow in a situation where the oil pump 5 is activated. For this purpose, the direction of rotation is changed to the second direction of rotation 12. To activate the oil pump 5, the actuator motor 2 is now energized in the second direction of rotation 12 in order to overcome the holding torque of the brake 6.

[0042] Due to the planetary gear 3 with its two outputs, torque is now applied to both outputs, the ring gear 3b and the sun gear 3d. However, the ring gear 3b is fixed via the end stop 13 of the parking lock / clutch / shift mechanism 7.

[0043] As soon as the oil pump 5 starts to rotate, oil pressure is built up and the brake 6 is opened via a hydraulic connection 6a.

[0044] Figure 6 shows the situation when the oil pump 5 is fully operational.

[0045] Once the brake 6 is fully open, it no longer generates a braking torque and the entire power flow goes from the actuator motor 2 via the also open freewheel 4 to the oil pump 5.

[0046] The advantage of this arrangement is that the planetary gear 3 increases the speed of the actuator motor 2, thus allowing the oil pump 5 to operate at a higher speed.

[0047] If you want to close the parking lock again or open the parking lock / clutch / gear, the direction of rotation must be reversed back to the first direction of rotation 11. This locks the sun gear 3d again via the freewheel 4 and the brake 6.

[0048] Reference sign

[0049] 1 actuator system

[0050] 2 actuator motors

[0051] 3 planetary gears

[0052] 3a Planetary Carrier

[0053] 3b Ring gear

[0054] 3c planetary gear

[0055] 3D sun wheel

[0056] 4 Freewheel

[0057] 5 Oil pump

[0058] 6 Brake

[0059] 6a hydraulic connection

[0060] 7 mechanical actuation / parking lock / clutch / shifting

[0061] 8 Oil inlet

[0062] 9 Oil outlet

[0063] 10 Actuating wheel

[0064] 11 first direction of rotation

[0065] 12 second direction of rotation

[0066] 13 End stop

Claims

Claims 1. Actuator system (1) with an electric actuator motor (2) which is connected on the drive side via a planet carrier (3a) of a planetary gear (3) which is connected on the output side via a ring gear (3b) to an actuating wheel (10) for mechanical actuation (7) and is connected via a sun gear (3d) and a freewheel (4) to an oil pump (5) and a brake (6) downstream of the oil pump (5), wherein the ring gear (3b) can be fixed via an end stop (13) of the mechanical actuation (7).

2. Actuator system (1 ) according to claim 1 , characterized in that the mechanical actuation (7) relates to a parking lock, a clutch, a switching mechanism.

3. Actuator system (1 ) according to claim 1 or 2, characterized in that the actuator motor (2) rotates in two directions of rotation, wherein in a first direction of rotation (11) the mechanical actuation (7) is activated.

4. Actuator system (1 ) according to one of the preceding claims, characterized in that in a second direction of rotation (12) the mechanical actuation (7) is deactivated and the oil pump (5) is driven.

5. Actuator system (1 ) according to one of the preceding claims, characterized in that a torque amplification from the actuator motor (2) to the mechanical actuation (7) is provided by the planetary gear (3).

6. Method for actuating an actuator system (1) according to one of the preceding claims, wherein, to activate the mechanical actuation (7), the actuator motor (2) rotates in a first direction of rotation (11) and drives the planet carrier (3a) of the planetary gear (3), wherein the output is via the ring gear (3b) to the actuating wheel (10) and the sun gear (3d) of the planetary gear (3) is locked in this first direction of rotation (11) by the freewheel (4), wherein the brake (6) is closed, and in which the oil pump (5) is activated, whereby the direction of rotation of the actuator motor (2) is changed to the second direction of rotation (12) in order to overcome the holding torque of the brake (6) and wherein the planetary gear (3) with its two outputs applies torque to both outputs, the ring gear (3b) and the sun gear (3d), wherein the ring gear (3b) is fixed via the end stop (13) of the mechanical actuation (7) and as soon as the oil pump (5) starts to rotate, oil pressure is built up and the brake (6) is opened via a hydraulic connection (6a).

7. Method according to claim 6 characterized in that the planetary gear (3) increases the speed of the actuator motor (2) by means of the summing circuit and thus the oil pump (5) is operated at a higher speed.

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