PARKING LOCK FOR A MOTOR VEHICLE AND METHOD FOR OPERATING A PARKING LOCK

Abstract

An electromechanical parking lock for a motor vehicle includes a locking element for reversible engagement in a parking lock wheel, an actuating element that can be pre-loaded by an actuating spring in order to insert the locking element into the parking lock wheel, an electric motor with an actuating unit for moving the actuating element out of the locked position (P) against the spring force of the actuating spring into an unlocked position (nP), and a solenoid that, in the unlocked position (nP), holds the actuating element pre-loaded via a securing element. The parking lock has an emergency locking position (Not-P) in which the parking lock is unlocked and in which the securing element can be released by the electric motor without changing the state of the solenoid so that the locked position (P) can be assumed.

Claims

1. An electromechanical parking lock for a motor vehicle, comprising: a locking element for reversible engagement in a parking lock wheel, an actuating element that can be pre-loaded by an actuating spring in order to insert the locking element into the parking lock wheel, an electric motor with an actuating unit for moving the actuating element out of the locked position (P) against the spring force of the actuating spring into an unlocked position (nP), and a solenoid that, in the unlocked position (nP), holds the actuating element pre-loaded via a securing element, wherein the parking lock has an emergency locking position (Not-P) in which the parking lock is unlocked and in which the securing element can be released by the electric motor without changing the state of the solenoid so that the locked position (P) can be assumed.

2. The electromechanical parking lock according to claim 1, wherein the unlocked position (nP) is spatially arranged between the emergency locking position (Not-P) and the locked position (P).

3. The electromechanical parking lock according to claim 1, wherein the electric motor has an electric motor shaft to which a coupling element can be connected which, when the solenoid is inoperable, triggers the securing element by means of the electric motor in that the actuating unit can be displaced beyond the unlocked position (nP) into the emergency locking position (Not-P).

4. The electromechanical parking lock according to claim 1, wherein the securing element is pre-loaded by a securing spring.

5. The electromechanical parking lock according to claim 3, wherein the securing element can be actuated via a ramp of the coupling element.

6. The electromechanical parking lock according to claim 3, wherein the coupling element is not loaded by moving the actuating unit between the locked position (P) and the unlocked position (nP) and moves the coupling element when actuating beyond the unlocked position (nP).

7. The electromechanical parking lock according to claim 6, wherein the coupling element has a window in which a control edge connected to the electric motor shaft is arranged, which can move freely in the window between the locked position (P) and the unlocked position (nP), wherein the control edge acts on a body edge of the window in the emergency locking position (Not-P).

8. The electromechanical parking lock according to claim 1, wherein the actuating unit is not designed to be self-locking and that the actuating unit has a spindle drive with a spindle nut which is spring-loaded in the locked position (P).

9. A method for operating the electromechanical parking lock of claim 1, wherein the actuating unit is moved in a first operating mode only between the unlocked position (nP) and the locked position (P), and in that in the event of a malfunction of the solenoid the actuating unit, in a second operating mode, is moved by the electric motor into an emergency locking position (Not-P).

10. The method according to claim 9, wherein the movement from the unlocked position (nP) to the emergency locking position (Not-P) is opposite to the movement direction from the unlocked position (nP) to the locked position (P).

11. An electromechanical parking lock for a motor vehicle, comprising: a locking element for reversible engagement in a parking lock wheel; an actuating spring having a spring force; an actuating element arranged to be pre-loaded by the actuating spring to insert the locking element into the parking lock wheel; an electric motor with an actuating unit for moving the actuating element against the spring force out of a locked position (P) into an unlocked position (nP); a securing element; a solenoid arranged to hold the actuating element pre-loaded via the securing element in the unlocked position (nP); and an emergency locking position (Not-P) in which: the electromechanical parking lock is unlocked; and the electric motor is arranged to release the securing element to assume the locked position (P) without changing a state of the solenoid.

12. The electromechanical parking lock of claim 11, wherein the unlocked position (nP) is spatially arranged between the emergency locking position (Not-P) and the locked position (P).

13. The electromechanical parking lock of claim 11 further comprising a securing spring, wherein the securing element is pre-loaded by the securing spring.

14. The electromechanical parking lock of claim 11 further comprising a coupling element, wherein: the electric motor comprises an electric motor shaft connectable to the coupling element; and when the solenoid is inoperable, the coupling element triggers the securing element by means of the electric motor to displace the actuation unit beyond the unlocked position (nP) into the emergency locking position (Not-P).

15. The electromechanical parking lock of claim 14, wherein: the coupling element comprises a ramp; and the securing element can be actuated via the ramp.

16. The electromechanical parking lock of claim 14; wherein: the coupling element is stationary when the actuating unit moves between the locked position (P) and the unlocked position (nP); and the coupling element is displaced within the actuating unit moves beyond the unlocked position (nP).

17. The electromechanical parking lock of claim 16 further comprising a control edge connected to the electric motor shaft, wherein: the coupling element comprises a window with a body edge; the control edge is arranged in the window; the control edge can move freely in the window between the locked position (P) and the unlocked position (nP); and the control edge acts on the body edge in the emergency locking position (Not-P).

18. The electromechanical parking lock of claim 11, wherein: the actuating unit is not designed to be self-locking; and the actuating unit comprises a spindle drive with a spindle nut which is spring-loaded in the locked position (P).

19. A method for operating the electromechanical parking lock of claim 11, comprising: moving the actuating unit only between the unlocked position (nP) and the locked position (P) in a first operating mode; and after a malfunction of the solenoid, moving the actuating unit with the electric motor into an emergency locking position (Not-P).

20. The method of claim 19, wherein a movement direction for moving the actuating unit from the unlocked position (nP) to the emergency locking position (Not-P) is opposite to a movement direction for moving the actuating unit from the unlocked position (nP) to the locked position (P).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The disclosure is described below with reference to a single schematically illustrated exemplary embodiment.

DETAILED DESCRIPTION

[0030] The single FIGURE shows a parking lock 1 in which a locking element in the form of a pawl 2 is movable relative to a parking lock wheel (not shown), for locking a motor vehicle. As a locking pawl, the pawl 2 can be pivoted about a pivot axis a and has a locking tooth 20 at its end facing away from the pivot axis a, with which it engages in one of the recesses of the locking teeth of the parking lock wheel and thus locks the parking lock 1. A return spring 19 secured to the parking lock housing and hooked onto the pawl 2 ensures that the pawl 2 does not fall unintentionally into one of the recesses of the parking lock wheel in the unlocked state due to gravity or as a result of vibrations.

[0031] The parking lock 1 is locked or unlocked by means of an actuating element 4, which is designed as a slide 15 with an actuating rod 23. The slide 15 has a slide housing 17 as a holder in which two radially offset rollers 16, 18 are held. One of the rollers 18 rolls on the pawl back 21, which forms a height profile, so that with linear displacement of the slide 15, the pawl 2 is rotated. The other roller 16 rolls on a reinforcement in the parking lock housing (not shown).

[0032] The box-shaped slide 15 is pre-loaded by the actuating spring 3 so that it moves the pawl 2 in the direction of the parking lock wheel without external force and locks the parking lock 1 (locked position, state P). The slide 15 can be displaced along the linear axis s.

[0033] To move the parking lock 1 from the locked position P to the unlocked position nP (unlocked), an electric motor 5 serves as the actuator. Its rotating electric motor shaft 6 is converted into a linear motion by a spindle drive.

[0034] In stationary operation and thus in both the unlocked position nP and the locked position P, the electric motor 5 is always in its same starting position. If the parking lock 1 is to be disengaged, the electric motor 5 pushes the slide 15 via an actuating unit 24 with a slide actuator 25 against the forces of the actuating spring 3 and an optional further spring 22 into the unlocked position nP, in which the parking lock 1 is held by the securing element 8. For this purpose, the securing element 8 engages in a recess 10 of an actuating rod 23 connected to the slide 15 and is secured there by the securing spring 12. The electric motor 5 then moves back to its initial position with its actuating unit 24.

[0035] The activation of the parking lock 1 (engagement) is performed by the solenoid 7. The securing element 8 retracts from the recess 10, thus allowing the parking lock 1 to be engaged by the actuating spring 3.

[0036] In the event that solenoid 7 fails and parking lock 1 is to be activated from the unlocked position nP, the following emergency locking mechanism is provided: The electric motor 5 moves from its locked position P to the unlocked position nP, in which the slide actuator 25 contacts the slide 15 as part of the actuating unit 24. The electric motor 5 moves beyond this and further pre-loads the actuating spring 3 until a control edge 14 of the actuating unit 24 contacts a coupling element 9. For this purpose, the coupling element 9 has a window 13 in which the control edge 14 can move freely between the locked position P and the unlocked position nP. If the actuating unit 24 is moved beyond the unlocked position nP, the control edge 14 and the coupling element 9 come into contact, so that the coupling element 9 is displaced to an emergency locking position Not-P. The coupling element 9 has a ramp 11 for emergency unlocking, which can only act on the securing element 8 and release it from the recess 10 in the emergency locking position Not-P. This releases the actuating spring 3. The actuating unit 24 moves back to the initial position.

[0037] In the other case, when the electric motor 5 fails and the parking lock 1 is to be activated from the unlocked position nP, the following emergency locking mechanism is provided: An emergency energy storage device (not shown), which can be small in contrast to the vehicle battery required to operate the electric motor 5, such as a capacitor, can release the solenoid 7. Since the actuating unit 24 is in the initial position except when the parking lock is disengaged, and thus in particular in the unlocked position nP, engagement of the parking lock 1 is always possible due to the lack of self-locking of the actuating unit 24.

[0038] The parking lock 1 according to the disclosure can thus always be activated, regardless of whether the solenoid 7 or the electric motor 5 fail. This redundant activation option means that a safe vehicle state can always be achieved even in vehicles with electromechanically activated parking locks, even in the event of a fault, if one of the two activation options fails.

REFERENCE NUMERALS

[0039] 1 Parking lock [0040] 2 Pawl [0041] 3 Actuating spring [0042] 4 Actuating element [0043] 5 Electric motor [0044] 6 Electric motor shaft [0045] 7 Solenoid [0046] 8 Securing element [0047] 9 Coupling element [0048] 10 Recess [0049] 11 Ramp [0050] 12 Securing spring [0051] 13 Window [0052] 14 Control edge [0053] 15 Slide [0054] 16 Roller [0055] 17 Slide housing [0056] 18 Roller [0057] 19 Return spring [0058] 20 Locking tooth [0059] 21 Pawl back [0060] 22 Further spring [0061] 23 Actuating rod [0062] 24 Actuating unit [0063] 25 Slide actuator [0064] a Pivot axis [0065] s Linear axis [0066] P Locked position [0067] nP Unlocked position [0068] Not-P Emergency locking position