Parking brake latch

Abstract

Parking lock latch (1) with an engagement contour (3) at a first component end (A) and a bearing eyelet (6) at a second component end (B), wherein the engagement contour (3) is tooth-like and a latch body (4) extends linearly between the two component ends (A, B), wherein this latch body (4) has a central area (7) between the two component ends (A, B), wherein the parking lock latch (1) has a material thickening (9) in the area of ​​the engagement contour (3) to an engagement contour thickness (D3), characterized in that the material thickening (9) degrades towards the central area (7), wherein around the bearing eyelet (6) and along the pawl body (4) there is a further material thickening (8a, 8b) to a bearing eyelet strut thickness (D2), wherein the further material thickening (8a, 8b) along the latch body as two outer struts in the direction of the central area (7) decreasing from the bearing eyelet strut thickness (D2), where a pawl thickness (D1) describes the regular material thickness of the pawl (1), wherein the central area (7) has this pawl thickness (D1) throughout, while the material thickening (9) with the engagement contour thickness (D3) describes the maximum material thickness that forms a pawl tooth, where the thicknesses (D1, D2, D3) are staggered, i.e. the pawl thickness (D1) is smaller than the bearing eyelet strut thickness (D2), and the bearing eyelet strut thickness (D2) is smaller than the engagement contour thickness (D3).

Description

[0001] The present invention relates to a parking lock latch with an engagement contour at a first component end and a bearing eyelet at a second component end, wherein the engagement contour is tooth-like and a latch body extends linearly between the two component ends. State of the art

[0002] Corresponding pawls and parking lock assemblies are used in the drive trains of motor vehicles to ensure a secure state when the vehicle is parked, particularly to prevent it from rolling away. An actuating mechanism moves the stationary, rotatable pawl so that at least part of it engages with a corresponding contour, for example, of a parking lock wheel. This then rotationally locks the parking lock wheel and associated components, such as the drive train shafts, in place.

[0003] The most highly stressed component in parking lock systems is the parking lock pawl. It is subject to tensile and compressive stresses at the engagement contour in the tooth root area of ​​the engaging tooth, as well as surface pressure on the tooth flank. These stresses can be reduced using various methods, such as widening the pawl and optimizing the tooth root geometry. However, conditions also arise during the actuation of the parking lock pawl that distribute the load unevenly along the tooth-parking lock wheel contact line.

[0004] The output shaft in the gearbox can have helical teeth.

[0005] Under high load, the helical gearing of the shaft on which the parking pawl sits is axially displaced relative to the parking pawl. The engaging tooth moves along with the parking pawl due to frictional forces, but the parking pawl bearing in the housing does not.

[0006] The housing stiffness in the parking lock pawl bearing is also usually not completely symmetrical on both sides of the parking lock pawl and leads to misalignment of the parking lock pawl bolt.

[0007] This significantly increases the asymmetry of the load on the tooth and the parking pawl, creating a highly inhomogeneous stress distribution. Since the installation space for the parking pawl is limited in all directions, physical limitations arise in the design optimization of the parking pawl in heavy vehicles such as electric vehicles.

[0008] Various parking lock arrangements are known from the prior art. For example, DE 10 2015 206 157 A1 discloses a parking lock arrangement with an actuating element for operating a parking lock pawl. Depending on its actuation state, the parking lock pawl can lock or release a parking lock wheel. A drive unit has a cam contour by means of which a rotary movement can be converted into an axial movement of the actuating element for locking or releasing the parking lock wheel. The parking lock pawl is claw-shaped and has a contour at a first free end for engaging the parking lock wheel, while at a second free end it has a receptacle for rotatable mounting.

[0009] DE 10 2019 209 453 A1 discloses a pawl having an engagement contour at a first component end and a bearing eyelet at a second component end. The engagement contour is tooth-shaped. The pawl has a concave curvature from the tooth-shaped engagement contour towards the second component end, transitioning into a convex curvature in the area of ​​the bearing eyelet.

[0010] The first and second component ends are diametrically opposed to each other. In an engaged or activated state of the parking lock assembly, the engagement contour engages with a corresponding contour of a parking lock wheel.

[0011] A bearing eyelet describes a passage or bore in the pawl, whereby, in an assembled state, a pin or pin-like element protrudes through the bearing eyelet. This allows the pawl to rotate around the pin or bearing eyelet. The convex curvature is located in the area of ​​the bearing eyelet, with its shape following a radius of the bearing eyelet, at least within a certain angular segment.

[0012] In a section of the engagement contour and the concave section, the pawl features a material thickening. This reinforces the pawl, particularly in a highly stressed area of ​​the engagement contour, enabling it to withstand higher loads. The material thickening has an arc-like increase in thickness, preventing stress concentrations from forming at edges. In addition to the material thickening at the first end of the component, a projection of the pawl extends onto the side of the bearing eyelet facing away from the engagement contour. This projection acts as a counterweight to the material thickening in the engagement contour area.

[0013] German patent DE 10 2018 129 680 A1 discloses a parking lock with a pawl whose pawl tooth has a thickness equal to that of the pawl body. CN 203 146 799 U1 discloses a pawl whose ends are thickened relative to the pawl body.

[0014] The purpose of the invention is to present a parking lock latch which is significantly less sensitive to misalignment. Description of the invention

[0015] The problem is solved with a parking lock pawl having an engagement contour at a first component end and a bearing eye at a second component end, wherein the engagement contour is tooth-like and a pawl body extends linearly between the two component ends, wherein the parking lock pawl has a material thickening in the area of ​​the engagement contour to an engagement contour thickness D3, wherein the material thickening degrades towards a central area.

[0016] The degrading process can lead to a reduction in thickness in steps or continuously.

[0017] Around the bearing eye and along the latch body there is a further thickening of material, which runs as two outer struts towards a central area, decreasing in a bearing eye-strut thickness D2.

[0018] The central area of ​​the parking lock latch has a latch thickness D1 that is smaller than the thicknesses D2, D3 of the material thickenings.

[0019] Furthermore, it is advantageous that wings are attached to the latch body as stiffeners perpendicular to the material thickenings in the y-direction.

[0020] To reduce inertia, a recess is provided in the area of ​​the wing. Description of the characters Fig. Figure 1 shows a section xy of the parking lock latch, Fig. Figure 2 shows a three-dimensional view of the parking lock latch. Fig. Figure 3 shows a view of the parking lock handle. Fig. Figure 4 shows a section xz through the center point of the bearing eyelet.

[0021] Fig. Figure 1 shows an embodiment of the parking pawl 1 according to the invention. This pawl has a hook-shaped design with an elongated, linearly extending pawl body 4. A toothed engagement contour 3 is provided at a first component end A. In an engaged state, the pawl 1 engages with this engagement contour 3 into a corresponding contour or toothing of a parking lock wheel (not shown).

[0022] Starting from the engagement contour 3, the parking lock latch 1 extends linearly towards a second component end B to the bearing eyelet 6 along an axis x.

[0023] Starting from the engagement contour 3, a wing 5b and a wing 5a are attached, increasing the overall height in the y-direction of the parking lock latch and extending into the linear latch body 4. These serve to compensate for the stiffness of the central area with thickness D1.

[0024] Along the latch body 4, starting from a central area 7 and extending to the bearing eyelet 6, material thickenings 8a and 8b extend above and below the latch body surface 4a, respectively. These material thickenings are arranged on both sides of the latch body. The bearing eyelet 6 is also contained within the material thickenings 8a and 8b. The material thickness decreases continuously up to the central area 7.

[0025] A further material thickening 9 in the z-direction is most pronounced at the engagement contour 3 and forms the width in the z-direction of the pawl tooth. The material thickening 9 decreases continuously towards the second component end B up to the central region 7. This creates a weakening of the parking pawl 1 in the central region. This gives the parking pawl increased flexibility in the transverse direction, allowing the pawl tooth area to adapt to the displacements and deformations of the adjacent systems.

[0026] Between the bearing eyelet 6 and the engagement contour 3, more precisely in the area of ​​the wing 5a, in a region subject to minimal stress, the pawl 1 has an optional recess 10. This serves to reduce weight and to compensate for the moment of inertia of the thickenings and wings of the pawl 1.

[0027] Overall, the parking lock latch 1 has three different material thicknesses, as can be seen from the Fig. 3 and Fig.4 can be seen.

[0028] A first thickness D1 describes the regular material thickness of the pawl 1, while the material thickenings 8a and 8b describe a second maximum material thickness D2, and the material thickening 9 describes a third maximum material thickness D3. The thicknesses D2 and D3 are subject to a continuous or stepped reduction in magnitude until they reach the central region 7.

[0029] The material thicknesses are staggered as D1 <D2<D3. Die maximale Dicke D3 liegt im Bereich der Eingriffskontur der Parksperrenklinke vor. Dadurch wird ein Klinkenzahn ausgebildet, der einen große Dicke D3 aufweist. Dadurch werden die Kräfte auf der Eingriffslinie gut verteilt, ohne dass allzu viel Bauraum durch eine insgesamt dicke Parksperrenklinke verbraucht würde.

[0030] Furthermore, an axial support surface 11 can be provided at the first component end A. This surface is located at the first component end A above the engagement contour. In particular, the pawl 1 comes into axial contact with a preferably machined, housing-fixed area here, in case the thickening D3 in the axial structure of the gearbox could lead to tolerance-related collisions with adjacent components, such as gears. Reference sign 1 locking pawl 3 Intervention contour 4 jack bodies 5a, 5b Wing 6 storage eyelets 7 Middle area 8a, 8b Material thickening 9 Material thickening 10 Exclusion 11 Support surface A first component end B second component end D1 pawl thickness D2 Bearing eyelet strut thickness D3 Intervention contour thickness

Claims

[1] Parking lock latch (1) with an engagement contour (3) at a first component end (A) and a bearing eyelet (6) at a second component end (B), wherein the engagement contour (3) is tooth-like and a latch body (4) extends linearly between the two component ends (A, B), wherein this latch body (4) has a central area (7) between the two component ends (A, B), wherein the parking lock latch (1) has a material thickening (9) in the area of ​​the engagement contour (3) to an engagement contour thickness (D3), characterized by , that the material thickening (9) degrades towards the central area (7), wherein around the bearing eyelet (6) and along the pawl body (4) there is a further material thickening (8a, 8b) to a bearing eyelet strut thickness (D2), wherein the further material thickening (8a, 8b) along the latch body as two outer struts in the direction of the central area (7) decreasing from the bearing eyelet strut thickness (D2), where a pawl thickness (D1) describes the regular material thickness of the pawl (1), wherein the central area (7) has this pawl thickness (D1) throughout, while the material thickening (9) with the engagement contour thickness (D3) describes the maximum material thickness that forms a pawl tooth, where the thicknesses (D1, D2, D3) are staggered, i.e. the pawl thickness (D1) is smaller than the bearing eyelet strut thickness (D2), and the bearing eyelet strut thickness (D2) is smaller than the engagement contour thickness (D3). [2] Parking lock latch (1) according to claim 1, characterized by , that wings (5a, 5b) are attached as stiffeners to the latch body (4) perpendicular to the material thickenings in the y-direction. [3] Parking lock latch (1) according to one of the preceding claims, characterized by , that a recess (10) is provided in the area of ​​the wing (5a) to reduce the moment of inertia.

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