Electromechanical parking lock actuator

Abstract

Electric parking lock actuator (10) for actuating a parking lock (12) in a motor vehicle, comprising an actuator housing (32) in which an actuator shaft (42) is mounted, which serves to drive an actuating element (26) acting on a pawl (18) of a parking lock (12) via a shaft end protruding from the actuator housing (32), and comprising an electric motor (36) housed in a motor housing (34), the motor shaft (52) of which is operatively connected to the actuator shaft (42) via a gear mechanism (40) arranged in the actuator housing (32), wherein the motor housing (34) is connected to the actuator housing (32) by means of a bayonet connection (38), and wherein a spring element is arranged in the motor housing (34) which axially acts on the electric motor (36) and which axially biases the electric motor (36) against a shoulder (80) of the actuator housing (32).

Description

[0001] The present invention relates to an electromechanical parking lock actuator according to the preamble of claim 1. Such a parking lock actuator serves to actuate a parking lock arranged in a motor vehicle, which in turn is designed to prevent the motor vehicle from unintentionally rolling away in a locked position. In particular, the invention relates to electromechanical parking lock actuators such as those used, for example, in electrically powered motor vehicles or in motor vehicles with hybrid transmissions, automated transmissions, or automatic transmissions in the automotive industry.

[0002] Parking locks are particularly necessary when the braking effect of the stationary drive (engine) is insufficient to hold the vehicle in place, or cannot be used, for example, due to normally open clutch elements. The drivetrain is then typically locked by a parking lock wheel with teeth, which is fixed to rotation on an output shaft of the transmission. This wheel can be positively locked to the teeth by means of a parking lock pawl pivotally mounted on a parallel axis. The parking lock pawl is biased by the force of a return spring, either away from the parking lock wheel into an unlocked position or towards the parking lock wheel into the locked position. In addition to hydraulic mechanisms, electric or other types of mechanisms can be used to pivot the parking lock pawl against the force of the return spring.Electromechanical parking lock actuators are used to generate a linear movement, or at least a substantially linear movement, by which an actuating element—which may be, for example, a cam, a cone, or a carrier with two rollers—can be moved against the parking lock pawl to pivot it. To ensure that the parking lock can engage and thus prevent the vehicle from rolling away even if the parking lock pawl, when actuated, comes into contact with a tooth of the parking lock wheel without engaging the toothing, an energy storage device (return spring) is also provided on the actuating element. This energy storage device, in the event of the vehicle rolling, advances the parking lock pawl via the actuating element so that it engages with the toothing of the parking lock wheel.In addition, in many cases an emergency operating mechanism must be provided which allows the parking lock to be engaged in the event of an actuator failure.

[0003] Electromechanical parking lock actuators with these functions are known from the prior art. For example, German patent application DE 102 12 038 A1 describes an electromechanical parking lock actuator comprising an electric motor and a coupling device with two rotatably mounted coupling parts. One coupling part is operatively connected to the motor shaft of the electric motor via a gear mechanism, while the second coupling part, which can be optionally detached, serves to displace an actuating rod eccentrically articulated to it in order to act on the pawl of a parking lock. A housing arrangement for this parking lock actuator is not disclosed.

[0004] From DE 10 2016 014 523 A1, an electric parking lock actuator for actuating a parking lock in a motor vehicle is known, in which an electric motor moves an actuating rod projecting from the actuator housing, which carries an actuating element for actuating the parking lock at its free end, axially back and forth between a locked position and an unlocked position via a gear mechanism housed in an actuator housing. The electric motor is housed in a separate motor housing, which is flanged to the actuator housing.

[0005] Parking barrier modules or parking barrier arrangements are also known from DE 10 2018 003 752 A1, DE 10 2018 006 098 A1 and DE 10 2010 029 400 A1.

[0006] The present invention is based on the objective of proposing a simple electromechanical parking lock actuator of the type mentioned above for actuating a parking lock in a motor vehicle, which, with its compact design, enables simple, safe and quick installation.

[0007] This problem is solved according to the invention by an electromechanical parking lock actuator according to claim 1. Advantageous embodiments and expedient further developments of the invention will become apparent from the dependent claims, the description, or the figures, wherein features described or shown here individually or in any combination with one another can constitute an object of the invention, unless the context clearly indicates otherwise.

[0008] In an electromechanical parking lock actuator intended for actuating a parking lock in a motor vehicle, comprising on the one hand an actuator housing in which an actuator shaft is rotatably or pivotably and / or axially displaceably mounted, which serves to drive an actuating element acting on the pawl of a parking lock directly or indirectly via intermediate elements such as an actuating rod with a shaft end protruding from the housing, and comprising on the other hand a separately designed motor housing in which an electric motor is received, which is provided to drive the actuator shaft via a gear mechanism arranged in the actuator housing, the motor housing is connected to the actuator housing via a bayonet connection according to the invention.

[0009] A significant advantage of the inventive design lies in the fact that, during assembly of the parking lock actuator, the motor housing can be attached to the actuator housing particularly easily and quickly using the bayonet connection, without the need for additional fasteners such as screws. Furthermore, this eliminates the risk of distortion in housings typically made of plastic, which can occur with energy-intensive joining processes such as welding. A bayonet connection, or a connection of the type of bayonet lock, therefore represents not only a very quick and easy-to-use, but also a particularly reliable means of attaching the motor housing to the actuator housing.

[0010] Furthermore, the parking lock actuator according to the invention is inexpensive to manufacture due to its simple design. Its compact construction also allows for easy installation even in confined spaces.

[0011] The parking lock actuator can also include a positive-locking and / or friction-locking coupling device within the actuator housing, comprising two rotatably or pivotably mounted coupling parts. A first coupling part is rotatably mounted on the actuator shaft, while the second coupling part is axially displaceable and rotationally fixed to the actuator shaft. Furthermore, a switching device, preferably formed by an electromagnet, for selectively opening or closing the coupling device can be provided within the actuator housing. The first coupling part is driven by the electric motor via the gear mechanism, which preferably includes a self-locking worm gear. When the coupling is closed, this rotational movement is transmitted to the second coupling part and thus to the actuator shaft, which is preferably rotationally fixed to it by means of a linear ball bearing.When the coupling device is open, the functional connection between the actuator shaft and the electric motor is disconnected, so that in an emergency operation a secondary drive, for example a spring, can drive the actuator shaft.

[0012] In the case of a bayonet connection, it is particularly advantageous if the motor housing is pot- or cup-shaped with a cylindrical housing wall surrounding the electric motor. This wall is closed at the axial end facing away from the actuator housing by a base. The motor housing has a bushing-shaped collar at its front open end opposite the base, which engages an annular connecting piece of the actuator housing, forming a mechanical interface with the actuator housing. Advantageously, the collar has an inner diameter larger than that of the cylindrical housing wall of the motor housing. This inner diameter radially surrounds the connecting piece of the actuator housing, which is also collar-shaped. The connecting piece has at least approximately the same inner diameter as the housing wall of the motor housing.

[0013] Furthermore, it is particularly advantageous if, for the formation of the bayonet connection, the connecting piece of the actuator housing has two or more radially projecting connecting projections on the outside, while the bushing-shaped collar of the motor housing has a corresponding number of internal joining recesses and undercuts connected thereto, designed to tightly receive the connecting projections, wherein the joining recesses for inserting the connecting projections extend from the open end of the collar of the motor housing and the undercuts are arranged at an axial distance from the open end of the collar and at an angle to the joining recesses.In such an arrangement, the connecting projections of the connecting sleeve, which are axially inserted via the joining recesses, can then be pivoted into the undercuts of the collar by rotating the motor housing. This axially secures the connecting sleeve of the actuator housing in the collar of the motor housing and thus brings the bayonet connection into its locked position. The joining recesses and the undercuts preferably each form an L-shaped recess, resulting in a plug-and-turn mechanism for mutually locking the two housings.

[0014] It is advantageous if at least one seal is inserted between the motor housing and the actuator housing. This ensures a liquid-tight connection between the two housings, which is beneficial, for example, when installing the parking lock actuator in an oil-filled transmission of a motor vehicle.

[0015] Preferably, the seal can be formed by an O-ring which is arranged in the area of ​​the bayonet connection between the collar of the motor housing and the nozzle of the actuator housing.

[0016] According to a particularly preferred embodiment of the invention, the actuator housing and / or the motor housing comprises one or preferably several locking element(s) which, in the locked state of the bayonet connection, are positively engaged and / or frictionally engaged with the respective other housing. This reliably prevents unintentional loosening of the bayonet connection.

[0017] Preferably, a locking element can be formed by an elastically deflectable spring arm with a locking lug molded onto it, which, in the locked state of the bayonet connection, engages a projection of the other housing, so that the two housings are locked together in the locked state of the bayonet connection.

[0018] According to a further particularly preferred embodiment of the invention, a spring element is arranged in the motor housing, which axially acts on the electric motor. This spring element presses the electric motor axially with its front end face or a front contact edge facing the actuator housing against an annular contact surface in the area of ​​the connecting stub or the mechanical interface of the actuator housing, thus exerting an axially directed preload force on the electric motor. In this way, possible tolerances can be compensated for and a secure position of the electric motor in the axially correct position can be ensured in a simple manner.

[0019] For precise positioning of the electric motor, it is particularly advantageous if the contact surface is formed by an inwardly directed annular shoulder in the connecting stub of the actuator housing, into which the electric motor engages with its front end face and is centered therein via its circumferential wall or a front projection.

[0020] A particularly simple embodiment of the spring element that axially acts on the electric motor can be achieved by an O-ring that is arranged axially between the bottom of the motor housing and the rear end face of the electric motor facing this bottom and is compressed there in the axial direction.

[0021] Furthermore, it is particularly advantageous for the exact positioning of the electric motor if the motor has a central projection on its rear end face facing the bottom of the motor housing, which engages positively in a central recess formed in the bottom of the motor housing and is centered therein.

[0022] For particularly easy assembly, it is advantageous if the O-ring that axially acts on the electric motor is placed on the central projection of the electric motor, so that it can be inserted into the motor housing together with the electric motor and brought into position.

[0023] Further advantages and features of the invention will become apparent from the following description of the exemplary embodiments illustrated in the drawings. The drawings show: Fig. 1: Schematic representation of a parking barrier with an electromechanical parking barrier actuator, Fig. 2: Perspective view of an electromechanical parking lock actuator according to the invention, Fig. 3: the motor housing of the parking lock actuator made of Fig. 2 alone, Fig. 4: A side view of the parking lock actuator from Fig. 2, and Fig. 5: a sectional view of the parking lock actuator from Fig. 4.

[0024] Fig. Figure 1 shows an electromechanical parking lock actuator 10, which is designed to actuate a parking lock 12 arranged in a motor vehicle. In this embodiment, both the parking lock 12 and the parking lock actuator 10 according to the invention are arranged within a transmission housing (not shown). The parking lock 12 has a parking lock wheel 14, which is rotationally and axially fixed on a transmission shaft (not shown) of a motor vehicle transmission and has a toothed section 16 on its outer circumference. For positive locking of the motor vehicle's drive train, the parking lock 12 further comprises a pawl 18, which is pivotably mounted to the transmission housing about a pivot axis 20 and has a locking tooth 22 that, when the pawl 18 pivots about the pivot axis 20, engages positively with the toothed section 16 of the parking lock wheel 14.A return spring, which is also not shown here and is supported against or suspended from the gearbox housing, engages the pawl 18 and biases the pawl 18 away from the parking lock wheel 14 into an unlocked position.

[0025] For pivoting the locking pawl 18 about the pivot axis 20, an actuating element 26 is provided, which in the illustrated embodiment has two rollers 28 and can be axially displaced by means of the parking lock actuator 10 either in a locking direction S or an unlocking direction E, as shown in the Fig. 1, Fig. 2 and Fig. 4 is indicated by arrows. The two rollers 28 are guided in a guide element 30 fixed to the gearbox housing, so that during an axial movement of the actuating element 26 in the locking direction S, one of the rollers 28 runs onto a chamfered engagement surface 24 of the pawl 18, while the other roller 28 is supported against the guide element 30. This causes the pawl 18 to lock against the force of the return spring (not shown). Fig. 1 pivots clockwise around the pivot axis 20 to engage the locking tooth 22 with the toothing 16 of the parking lock wheel 14 in a positive-locking manner. Conversely, during an axial movement of the actuating element 26 in the unlocking direction E, the roller 28 is pulled away from the engagement surface 24, resulting in the pawl 18 being forced into position by the force of the return spring. Fig. 1 is pivoted counterclockwise around the pivot axis 20, whereby the locking tooth 22 is removed from the toothing 16 and thereby disengages from the parking lock wheel 14.

[0026] The embodiment of Fig.Figure 2 shows a parking lock actuator 10 according to the invention comprising an actuator housing 32, preferably injection-molded from a plastic, on which mounting eyes 33 are integrally formed. These eyes serve to fasten the parking lock actuator 10 to a transmission wall (not shown) in a manner known per se, for example, by means of screws. A separately designed motor housing 34 is attached to the actuator housing 32, which accommodates an electric motor 36 inside. According to the invention, this fastening is effected by means of a bayonet connection 38, which will be described in more detail below. The electric motor 36 serves to drive an actuator shaft 42 via a gear mechanism 40 and a coupling device (not shown) in a rotating manner. The actuator shaft 42, via an eccentric device 44, converts the rotary movement into an at least approximately axial movement of an actuating rod 46, which carries the actuating element 26 for the parking lock 12.In normal operation of the parking lock actuator 10, the actuating rod 46 can be driven by the electric motor 36 in the locking direction S or, conversely, in the unlocking direction E. A return spring 48, designed here as a helical compression spring and surrounding the actuating rod 46, biases the actuating rod 46 or the actuating element 26 relative to a guide sleeve 50 of the eccentric device 44 in the direction of the locking position. In the embodiment shown here, the gear mechanism 40 consists of a self-locking worm gear in which a worm 54, mounted on the motor shaft 52 of the electric motor 36, drives a gear 56 that is operatively connected to the actuator shaft 42 via the coupling device and can be disengaged.

[0027] The bayonet connection 38 according to the invention between the actuator housing 32 and the motor housing 34 is described in more detail below. All directional terms such as "radial", "axial" or "circumferential" refer to the axis of rotation of the motor shaft 52, unless expressly stated otherwise.

[0028] The motor housing 34, which has a cylindrical housing wall 58 and a base 60, is cup-shaped overall. At its front open end, it features a bushing-shaped collar 62 with a larger diameter than the housing wall 58. This collar engages a similarly bushing-shaped connecting piece 64 of the actuator housing 32. To form the bayonet connection 38, the connecting piece 64 has two diametrically opposed connecting projections 66 that extend radially outwards and can be inserted into two corresponding insertion recesses. These insertion recesses are recessed on the inside of the collar 62 of the motor housing 34. Each insertion recess extends axially from the front open end of the collar 62 to an undercut that runs circumferentially at a distance from the front open end of the collar 62 and is also recessed on the inside of the collar 62 of the motor housing 34.The undercut designed to closely accommodate a connecting projection 66 therefore forms an L-shaped recess together with the associated joining recess, resulting in a plug-and-turn mechanism similar to a bayonet fitting for locking the two housings 32 and 34 together.

[0029] In such an arrangement, the connecting projections 66 of the connecting sleeve 64 can first be inserted axially into the joining recesses and then moved into the undercuts of the collar 62 by rotating the motor housing 34, in order to fix the connecting sleeve 64 of the actuator housing 32 axially in the collar 62 of the motor housing 34 and to lock the bayonet connection 38.

[0030] To prevent the bayonet connection 38 from unintentionally loosening, the collar 62 of the motor housing 34 features two circumferentially extending and axially deflectable spring arms 68 as locking elements, each with an integrally formed locking lug 70. When the motor housing 34 is rotated to lock the bayonet connection 38, the locking lugs 70, thanks to a forward deflection chamfer in the direction of rotation, engage two projections formed on the connecting piece 64 of the actuator housing 32 as the spring arms 68 deform. Behind these projections, after the spring arms 68 have rebounded to their original position, the locking lugs 70 provide a positive locking engagement, thus securing the locked state of the bayonet connection 38.

[0031] To prevent the ingress of gear oil into the housings 32 and 34, a first O-ring 72 is inserted as a seal between the collar 62 of the motor housing 34 and the connecting stub 64 of the actuator housing 32.

[0032] A second O-ring 76 is arranged axially between the base 60 of the motor housing 34 and the rear end face 74 of the electric motor 36. This O-ring acts as a spring element, applying axial force to the electric motor 36 and pressing its front contact edge 78 against an annular shoulder 80 extending inwards at the connecting stub 64, forming a contact surface. This ensures the correct axial positioning of the electric motor 36.

[0033] The second O-ring 76 surrounds a rear central projection 82, which the electric motor 36 has on its rear end face 74 and which engages positively in a central recess 84 formed in the base 60 of the motor housing 34 and is centered therein. At the front, the electric motor 36 is centered by a front central projection 86, which positively rests against the inner edge of the annular shoulder 80 formed on the base of the connecting piece 64. In this way, the electric motor 36 is also precisely positioned radially on both sides.

[0034] The connecting piece 64 forms a mechanical interface of the actuator housing 32, via which the motor housing 34, containing the electric motor 36, is connected to the actuator housing 32 by means of the bayonet connection 38. Additionally, the actuator housing 32 also has a common electrical interface 88, via which both the electric motor 36 and other electrical components of the parking lock actuator 10, for example, an electrical switching device (particularly formed by an electromagnet) for opening or closing the clutch assembly and / or a position detector for detecting the angular position of the actuator shaft 42, can be connected to and controlled by an external control unit. Reference symbol list: 10 parking barrier actuator 12 Parking restrictions 14 Parking lock wheel 16 gear teeth 18 Locking pawl 20 Swivel axis 22 locking tooth 24 attack surface 26 Actuating element 28 rolls 30 guide element 32 actuator housings 34 Engine housing 36 Electric motor 38 bayonet connection 40 Gear mechanism 42 Actuator shaft 44 Eccentric device 46 Actuating rod 48 Return spring 50 Guide sleeve 52 Motor shaft 54 snail 56 gear 58 Housing wall 60 floor 62 collars 64 connecting pieces 66 connecting projections 68 spring arms 70 Rastnase 72 first O-ring 74 rear front 76 second O-ring 78 front mounting edge 80 ring-shaped shoulder 82 rear central lead 84 centric recess 86 front central lead 88 electrical interface

Claims

[1] Electric parking lock actuator (10) for actuating a parking lock (12) in a motor vehicle, comprising an actuator housing (32) in which an actuator shaft (42) is mounted, which serves to drive an actuating element (26) acting on a pawl (18) of a parking lock (12) via a shaft end protruding from the actuator housing (32), and comprising an electric motor (36) housed in a motor housing (34), the motor shaft (52) of which is operatively connected to the actuator shaft (42) via a gear mechanism (40) arranged in the actuator housing (32), wherein the motor housing (34) is connected to the actuator housing (32) by means of a bayonet connection (38), and wherein a spring element is arranged in the motor housing (34) which axially acts on the electric motor (36) and which axially biases the electric motor (36) against a shoulder (80) of the actuator housing (32). [2] Electric parking lock actuator (10) according to claim 1, characterized by , that the motor housing (34) is pot-shaped with a cylindrical housing wall (58) surrounding the electric motor (36), which is closed at the axial end away from the bayonet connection (38) by a base (60), wherein the motor housing (34) has a bushing-shaped collar (62) at the open end, which engages an annular connecting stub (64) of the actuator housing (32) forming a mechanical interface. [3] Electric parking lock actuator (10) according to claim 2, characterized by, that to form the bayonet connection (38), the connecting piece (64) of the actuator housing (32) has radially projecting connecting projections (66), while the collar (62) of the motor housing (34) has internal joining recesses and associated undercuts designed to closely receive the connecting projections (66), wherein the joining recesses for inserting the connecting projections (66) extend from the open end of the collar (62) of the motor housing (34) and the undercuts are arranged at an angle to the joining recesses at an axial distance from the open end, so that the connecting projections (66) inserted via the joining recesses can be pivoted into the undercuts by rotating the motor housing (34) in order to engage the connecting piece (64) of the actuator housing (32) in the collar (62) of the motor housing when the bayonet connection (38) is locked. (34) to fix axially. [4] Electric parking lock actuator (10) according to any one of the preceding claims, characterized by , that at least one seal is arranged between the motor housing (34) and the actuator housing (32). [5] Electric parking lock actuator (10) according to claim 4 in conjunction with claim 2 or 3, characterized by , that the seal is an O-ring (72) inserted between the collar (62) of the motor housing (34) and the connecting stub (64) of the actuator housing (32). [6] Electric parking lock actuator (10) according to any one of the preceding claims, characterized by , that the actuator housing (32) and / or the motor housing (34) includes at least one locking element which, in the locked state of the bayonet connection (38), is positively engaged and / or force-fitted to the respective other housing (34, 32). [7] Electric parking lock actuator (10) according to claim 6, characterized by, that the at least one locking element is an elastically deflectable spring arm (68) with a locking lug (70) which, in the locked state of the bayonet connection (38), engages a projection of the other housing (34, 32), wherein the two housings (32, 34) are locked together in a latching manner. [8] Electric parking lock actuator (10) according to one of the preceding claims in conjunction with claim 2 or 3, characterized by , that the shoulder (80) is formed in the annular connecting sleeve (64) of the actuator housing (32), wherein the electric motor (36) engages in the connecting sleeve (64) of the actuator housing (32) and is centered therein. [9] Electric parking lock actuator (10) according to any one of the preceding claims, characterized by , that the spring element is formed by an O-ring (76) which is arranged axially between the base (60) of the motor housing (34) and the electric motor (36). [10] Electric parking lock actuator (10) according to any one of the preceding claims, characterized by , that the electric motor (36) has a central projection (82) on its side facing the bottom (60) of the motor housing (34), which engages positively in a recess (84) formed in the bottom (60) of the motor housing (34) and is centered therein. [11] Electric parking lock actuator (10) according to claims 9 and 10, characterized by , that the O-ring (76) surrounds the central projection (82) of the electric motor (36).

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