Ramp actuator and angular contact ball bearing unit with cold-formed outer ring and embossed ramp contour and method for producing a ramp disc

Abstract

Ramp actuator (1) for a motor vehicle transmission or a motor vehicle clutch, with a pivotable ramp disc (2) which has at least one ramp (4) on a first end face (5) which is designed for the rolling of a rolling element and, spaced therefrom, has a raceway (6) for bearing rolling elements (7) of a rolling bearing (8) designed for absorbing radial and axial forces, and with a bearing ring (9) which can be fixed on a shaft, characterized in that, on the one hand, the ratio of the axial width (17) of the ramp disc (2) relative to its support height (18) is between 2.9 and 4.1 and, on the other hand, the ratio between the ramp radius (19) of the ramp (4) of the ramp disc (2) relative to the support height (18) of the ramp disc (2) is between 0.7 and 1.3.

Description

[0001] The invention relates to a ramp actuator for a motor vehicle transmission or a motor vehicle clutch, with a pivotable ramp disc / a pivotable ramp ring, which can also be referred to as a pivot actuator disc and has an optional, for example, external toothing element, wherein the ramp disc / the ramp ring has at least one ramp on a first end face, which is prepared for the rolling of a rolling element, such as a ball, and spaced therefrom has a raceway for bearing rolling elements of a rolling bearing prepared to absorb radial and axial forces, and with a bearing ring which can be fixed on a shaft and is designed, for example, as a bearing inner ring and which in particular also has a raceway for the bearing rolling elements.

[0002] Clutch assemblies for motor vehicles are already known from the prior art. For example, WO 2018 / 099642 A1 discloses a clutch assembly for a motor vehicle comprising a friction clutch and an actuator unit for actuating the friction clutch, wherein the actuator unit has a ramp mechanism with a stationary first ramp disc and a second ramp disc movable relative to the first ramp disc. A coolant reservoir containing coolant is provided for lubricating the friction clutch, wherein the coolant reservoir is arranged geodetically above the central axis of the friction clutch with respect to the central axis.Furthermore, a metering unit is provided for controlling the coolant flow from the coolant reservoir into the friction clutch, wherein the metering unit is partially formed on or in the first ramp disc and is arranged geodetically below the central axis with respect to the central axis of the friction clutch.

[0003] Prior art of this type is also known from DE 10 2005 051 500 B3. This discloses an arrangement for measuring force on a friction clutch, particularly in the drive train of a motor vehicle. The arrangement comprises an outer disk carrier on which outer disks are held in a rotationally fixed manner and axially displaceable along a longitudinal axis "A." An inner disk carrier is provided on which inner disks are held in a rotationally fixed manner and axially displaceable along the longitudinal axis "A." The outer and inner disks are arranged axially alternately and together form a disk pack. Furthermore, the outer disk carrier is mounted for limited rotation relative to a housing about the longitudinal axis "A" and has at least one cam for rotational support.Force measurement means are also provided, which are to be arranged in the housing such that, upon actuation of the friction clutch, they are acted upon by the at least one cam in an effective direction extending at a distance transverse to the longitudinal axis. This earlier disclosure further relates to a gear arrangement with such a force measurement arrangement. Typically, the rolling elements rolling on the ramps of the ramp disc act on a stationary, i.e., non-rotating actuator disc, which executes an actuating movement. The invention also relates to such a combination in which a corresponding stationary actuator disc is integrated.

[0004] Prior art forming the generic type is also known from DE 10 2008 011 914 A1, which relates to a preloading unit with a first ramp disk and a second ramp disk, wherein the ramp disks have a plurality of ramp contours formed in one side of an annular surface of the ramp disks, wherein each ramp contour comprises a first ramp and a second ramp, so that a rolling element is arranged between the first and the second ramp disk in such a way that in the preloading unit, by rotating and pivoting at least one of the two ramp disks relative to the other ramp disk, the rolling elements ascend and / or descend on the ramp contours, wherein the ramp disks are designed in such a way that a plurality of cavities are formed between the side of the annular surface of the ramp disks which faces away from the ramp contours and the adjacent elements of the respective ramp disks.

[0005] Further prior art is also known from DE 10 2014 215 257 A1, which relates to a ramp system with a ramp seat, a counter-ramp seat which is rotatable relative thereto and ramp balls guided in the ramp seat and the counter-ramp seat, wherein the ramp seat and the counter-ramp seat each have ramp tracks which are connected to one another in the circumferential direction via an intermediate surface, wherein the ramp track of the ramp seat has a smaller gradient at its ramp edge pointing towards the counter-ramp seat relative to a radial plane running perpendicular to the axis of rotation than at its ramp base pointing away from the counter-ramp seat and / or the ramp track of the counter-ramp seat has a smaller gradient at its counter-ramp edge pointing towards the ramp seat relative to the radial plane than at its counter-ramp base pointing away from the ramp seat, wherein the ramp edge and / or the counter-ramp edge are bevelled at an angle relative to the radial plane.

[0006] In some applications, existing ramp actuators have been found to have a problem with heat treatment. Particularly with sintered ramp disks / actuator disks, problems arise due to increased wall thickness changes.

[0007] Furthermore, a two-piece version is often used, in which a single-row angular contact ball bearing is mounted with the sintered actuator disk. Unfortunately, this creates an additional tolerance chain, requiring further consideration of a further tolerance situation. In the initial step, combining an angular contact ball bearing with the actuator disk as a one-piece component has proven to be effective. Unfortunately, this currently requires a massive design, which is undesirable for reasons stated above, among others.

[0008] However, the disadvantages of the prior art are now to be avoided or at least reduced. In particular, uneven hardness application of the individual actuator disks due to large wall thickness variations is to be prevented. Additional tolerances between the actuator disk and the angular contact ball bearing are to be excluded. Furthermore, relative movement between the actuator disk and the angular contact ball bearing and increased wear are to be eliminated. The previously high space requirements due to a joint are to be avoided. Pre-assembly of the angular contact ball bearing in the actuator disk is to be eliminated. Furthermore, high material loss in the usual machining combination of actuator disk and angular contact ball bearing outer ring is to be avoided. A machining combination of the actuator disk and the angular contact ball bearing outer ring currently has to be through-hardened, which results in long hardening times, which is also to be avoided.Fundamentally, the long time and high costs associated with machining the ramp contour should be avoided. Material fibers should no longer be severed, thus increasing strength.

[0009] In summary, the goal is to ensure that adjustment units, comprising rolling bearings and a ramp actuator with a ramp mechanism, including a swivel actuator disc / ramp disc and a stationary actuator disc, no longer require excessive material / are manufactured using solid machining techniques. Nevertheless, high loads should be absorbed.

[0010] This is achieved according to the invention in a generic device in that, on the one hand, the ratio of the axial width of the ramp disc relative to its support height is between 2.9 and 4.1, preferably 3.0, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9 or 4.0, and on the other hand, the ratio between the ramp radius of the ramp of the ramp disc relative to the support height of the ramp disc is between 0.7 and 1.3, preferably 0.8, 0.9, 1.0, 1.1 or 1.2.

[0011] In other words, sheet metal material is used to create an adjustment unit. In the proposed solution, the fiber path is uninterrupted and extends from the end face of the ramp disk, which has the ramp contour, toward an opposite end face, following the outer contour of the component. The fiber path thereby approaches a radial inner edge of the end face with the ramp contour.

[0012] A solid ramp disk, as known from DE 10 2005 051 500 B3, is avoided. Nevertheless, three or five balls with / without an axial ball cage can be used. A bearing for the stationary actuator disk is also implemented. The bearing of the pivoting actuator disk, i.e. the pivotable ramp disk, is such that it actuates, for example, the plates of a plate pack of a multi-plate clutch, namely using the stationary actuator disk. Due to a relative rotational movement of the toothed actuator disk / ramp disk with respect to the stationary actuator disk / stationary actuator disk, the balls roll along a ramp geometry, whereby an axial offset results from the ramp gradient. This axial offset actuates a plate pack, via which shift states in the transmission can be mapped.

[0013] The ramp disc thus serves a dual function: to provide ramps for the balls to roll off and to provide a raceway for contacting the rolling elements of an angular contact ball bearing. This allows the realization of an adjustment unit for a release system for multi-plate clutches, such as in (differential) transmissions, with a stationary clutch disc on one side and an actuating element on the other. Embossing the ramp contour has proven effective in this case.

[0014] Advantageous embodiments are claimed in the subclaims and explained in more detail below.

[0015] It is therefore advantageous if, on the one hand, the ratio between the diameter of the bearing rolling element designed as a ball relative to the shoulder height of the bearing ring is ≥ 3:2, but < 10, 7.5 or 5 and, on the other hand, the wall thickness of the bearing ring at the apex of the bearing rolling element relative to the shoulder height of the bearing ring is between 0.2 and 0.6, preferably 0.3, 0.4 or 0.5 ±0.05.

[0016] An advantageous embodiment is also characterized by the ramp ring being designed as a sheet metal part manufactured without machining. Machining processes can then be omitted, allowing the fiber flow to remain uninterrupted and allowing for higher loads during operation.

[0017] It is advisable for the rolling bearing to be designed and installed as an angular contact ball bearing or an adjusted ball bearing. This allows a durable subassembly to be created using inexpensive standard components.

[0018] By providing three segmented ramps with a concave contour along the circumference of the ramp disk's face, force transmission can be optimized and tilting prevented. The result is excellent functionality.

[0019] An advantageous embodiment is also characterized in that the end face of the ramp disc is provided by a flange that has at least one radially projecting projection and / or grooves of the same type evenly distributed over the circumference. An electromotive pivoting movement by means of an electric motor can then be efficiently achieved due to a positive locking. Lubricant can also be efficiently supplied.

[0020] The invention also relates to a method for producing a ramp disc for a ramp actuator, wherein the ramp disc preferably has ratios of axial width of the ramp disc relative to its support height between 2.9 and 4.1 and a ratio between the ramp radius of the ramp of the ramp disc relative to the support height of the ramp disc between 0.7 and 1.3, and the steps of drawing, upsetting and stamping are carried out, preferably in this order.

[0021] The invention also relates to a further development of the method for producing a ramp disc for a ramp actuator, in particular comprising the steps of drawing, upsetting and embossing, wherein other steps or additional steps can also be present instead of these steps and the above-mentioned conditions are present or modified, wherein the smallest radial and / or axial wall thickness of the ramp disc is greater than the thickness of its starting material, such as a round blank.

[0022] It is advantageous if the ramp disc is trimmed and / or punched between drawing and compressing.

[0023] Furthermore, it is advantageous if the distance between the ramp surface and the raceway on the inside of the ramp disc for the balls of the angular contact ball bearing is greater at the thinnest point than the thickness of the starting material for the ramp disc.

[0024] A combination of the actuator disc with the ramp contour and the (bearing) outer ring of a single-row angular contact ball bearing is now presented, avoiding joints. This one-piece variant thus enables easier handling and assembly. A compact design with reduced installation space and weight is achieved. A non-cutting forming of the (bearing) outer ring is implemented, in particular using cold forming / deep drawing of a shoulder for the ball bearing raceway. The bearing raceway can be pre-stamped and possibly machined afterwards, e.g., using grinding and / or honing steps. 16MnCr5 has emerged as the preferred material. The required surface hardness can be achieved by case hardening. Case hardening is also suitable for cold forming. The forming process results in greater strength because it avoids severing the material fibers.

[0025] The shape is predefined from a round blank using deep drawing. The ramp geometry is produced by stamping and affects the required accuracy and surface quality. The bearing raceway is pre-stamped and then machined, if desired. The ball and raceway components are standard components wherever possible. Anti-twist protection by a lever or radially arranged grooves is desirable. An oil supply through radially arranged grooves is also desirable. In other words, an adjustment unit is now possible that is no longer solid and heavy and does not contain too much material. Machining processes have been omitted for cost reasons. The adjustment unit is assembled from sheet metal components that can withstand the high loads encountered during use.

[0026] The invention is explained in more detail below with the aid of a drawing. Different embodiments are shown. They show: Fig. 1 a perspective view of a first embodiment of a ramp actuator according to the invention in a partially sectioned representation, Fig. 2 a perspective view of only the pivoting ramp disc of the embodiment of Fig. 1, Fig. 3 another perspective view of the ramp disc from Fig. 2, Fig. 4 is a further perspective view of another ramp actuator according to the invention, Fig. 5 a longitudinal section through a single-row angular contact ball bearing and a ramp disc, as also shown in Fig. 4, for that specific embodiment of a ramp actuator, Fig. 6 a front view of the front side of the ramp disc with its three equally distributed ramps and the rolling bearing designed as a single-row angular contact ball bearing behind the ramp disc, Fig. 7 a longitudinal section through the ramp actuator and the Fig. 4 to 6, Fig. 8 to 11 show a further embodiment of a ramp actuator according to the representation of Fig. 4 to 7 and Fig. 12 to 14 show the process sequence for manufacturing the ramp disc.

[0027] The figures are merely schematic and serve only to clarify the invention. The same elements are designated by the same reference numerals.

[0028] In Fig. Figure 1 shows a first embodiment of a ramp actuator 1 according to the invention. The ramp actuator 1 has a pivotable ramp disc 2.

[0029] Ramp side 2 can also be referred to as a pivoting ramp ring or pivot actuator disc. Anticipating Fig. 10, attention is drawn to a toothing segment 3 designed as a toothing or projection for coupling an electric motor.

[0030] Returning to Fig. 1, the presence of a ramp 4 on a first end face 5 or a first end surface is noted. To be precise, there are three segment-like ramps 4, each with a concave surface for accommodating one or more balls, such as two, three, four, or five. These balls are not shown.

[0031] Spaced apart from this is a raceway 6, on which the bearing rolling elements 7 of a rolling bearing 8 designed to absorb radial and axial forces are mounted. This rolling bearing 8 also has a bearing ring 9, namely an inner bearing ring 10, which is designed to be mounted / fixed on a shaft. This shaft is not shown. The ramp disc 2 thus represents the outer bearing ring of the rolling bearing 8. A cage 11 may be provided to hold the bearing rolling elements 7 in position.

[0032] As in the Fig. 2 and Fig. 3, the ramp disc 2 thus has a flange / flange area 12 and a sleeve / sleeve area 13. The flange 12 represents the first end face 5 with the ramps 4, whereas the sleeve 13 represents the raceway 6 for the bearing rolling elements 7 of the rolling bearing 8.

[0033] Especially in Fig. 4 shows the presence of equally distributed recesses 14 projecting in the radial direction on the outside of the flange 12 of the ramp disc 2. In contrast, there are fundamentally differently designed recesses 14 in the embodiment of the ramp disc 2 according to the embodiment according to Fig. 8, wherein these recesses are designed as oil guide grooves 15 and are channel-shaped. In this embodiment, there is a radially projecting projection 16, which ultimately represents the toothed segment 3.

[0034] Coming back to the design of the Fig. 4 also refers to the Fig. 5 to 7. The axial width of the ramp disk 2 is designated by reference numeral 17. The support height is designated by reference numeral 18. The ramp radius is designated by reference numeral 19. The shoulder height of the ramp disk is designated by reference numeral 20. The diameter of the spherical bearing rolling element 7 is designated by reference numeral 21. The shoulder height of the bearing ring is designated by reference numeral 22. The wall thickness of the bearing ring at the apex of the bearing rolling element 7 is designated by reference numeral 23. The wall thickness of the ramp disk at the apex of the bearing rolling element is designated by reference numeral 24. The wall thickness 24 is determined by the smallest distance between the concave surface of the raceway on the ramp 4 for the corresponding ball and the raceway on the radial inside of the ramp disk 2 for the bearing rolling elements 7.

[0035] Rolling bearing 8 is a single-row angular contact ball bearing with an angle of 35° ±4°. However, contact angles greater or smaller than 35° are also conceivable.

[0036] The embodiment of the Fig. 8 to 11 is that of the Fig. 4 to 7 are highly similar and differ, however, particularly in the design of the oil guide grooves 15 or the recesses 14 and the projection 16.

[0037] Support heights, axial widths, and shoulder heights are conventional and defined as above. Note that the support height 18 of the ramp disc 2 is measured between a plane through the front face 5 and a plane on the rear face 25, whereas the axial width 17 of the ramp disc 2 is measured between that plane through the first front face 5 and a plane through the opposite front face 26. See in particular Fig. 9. The wall thickness 24 of the ramp disc 2 at the apex of the bearing rolling element 7 is aligned such that it is perpendicular to the concave surface in the area of ​​the ramp radius 19 of the ramp disc 2.

[0038] The shoulder height 22 of the bearing ring 9 is determined by the distance between a plane on the radial outer side of the bearing ring 9 and a likewise concentric reference plane through the apex of the bearing rolling element 7 in the bearing ring raceway 27. The contact line is referenced by reference numeral 28. It is inclined to both a radial and an axial axis. It has an inclination to the radial axis of 35° ±4°.

[0039] From the sequence of Fig. 12, Fig. 13 and Fig.14, the manufacturing method according to the invention can be derived, wherein a cup 30 is created from a round blank 29 by means of several forming steps, in particular drawing steps, which is then formed into the ramp disc 2 by means of upsetting and stamping. It is important that the raceway for the bearing rolling elements 7 can be introduced by means of a stamping process before or after the stamping of the ramp. List of reference symbols 1 ram actuator 2 Ramp disc / ramp ring 3 Gear segment 4 Ramp 5 first front side of the ramp disc 6 Career 7 bearing rolling elements 8 rolling bearings 9 Bearing ring 10 Bearing inner ring 11 Cage 12 Flange 13 sleeve 14 Recess 15 Oil guide groove 16 lead 17 axial width of the ramp disc 18 Support height of the ramp disc 19 Ramp radius of the ramp disc 20 Shoulder height of the ramp disc 21 Diameter of the spherical bearing rolling element 22 Shoulder height of the bearing ring 23 Wall thickness of the bearing ring at the apex of the bearing rolling element 24 Wall thickness of the ramp disc at the apex of the bearing rolling element 25 Back 26 second front side of the ramp disc 27 Bearing ring raceway 28 Contact line 29 Ronde 30 bowls

Claims

[1] Ramp actuator (1) for a motor vehicle transmission or a motor vehicle clutch, with a pivotable ramp disc (2) which has at least one ramp (4) on a first end face (5) which is prepared for the rolling of a rolling element and has, at a distance therefrom, a raceway (6) for bearing rolling elements (7) of a rolling bearing (8) prepared for the absorption of radial and axial forces, and with a bearing ring (9) which can be fixed on a shaft, characterized by that on the one hand the ratio of axial width (17) of the ramp disc (2) relative to its support height (18) is between 2.9 and 4.1 and on the other hand the ratio between the ramp radius (19) of the ramp (4) of the ramp disc (2) relative to the support height (18) of the ramp disc (2) is between 0.7 and 1.

3. [2] Ramp actuator (1) according to claim 1, characterized bythat on the one hand the ratio between the diameter (21) of the bearing rolling element (7) designed as a ball relative to the shoulder height (22) of the bearing ring (9) is ≥3:2 and on the other hand the wall thickness (23) of the bearing ring (9) at the apex of the bearing rolling element (7) relative to the shoulder height (22) of the bearing ring (10) is between 0.2 and 0.

6. [3] Ramp actuator (1) according to claim 1 or 2, characterized by that the ramp disc (2) is designed as a non-cutting sheet metal part. [4] Ramp actuator (1) according to one of claims 1 to 3, characterized by that the rolling bearing (8) is designed as an angular contact ball bearing. [5] Ramp actuator (1) according to one of claims 1 to 4, characterized by that there are three segment-like separated ramps (4) with a concave contour over the circumference of the front side (5) of the ramp disc (2). [6] Ramp actuator (1) according to one of claims 1 to 5, characterized bythat the end face (5) of the ramp disc (2) is provided by a flange (12) which has at least one radially projecting projection (16) or end face grooves (15) which are equally distributed and of the same type over the circumference. [7] Method for producing the ramp disc (2) of the ramp actuator (1) according to one of claims 1 to 6, wherein the steps of drawing, upsetting and stamping are carried out. [8] Method according to claim 7, wherein the smallest radial and / or axial wall thickness of the ramp disc (2) is greater than the thickness of its starting material for the ramp disc (2). [9] Method according to claim 7 or 8, wherein the ramp disc (2) is trimmed and / or punched between the drawing and the upsetting. [10] Method according to one of claims 7 to 9, wherein the distance between the ramp surface and the raceway (6) on the inside of the ramp disc (2) for the balls of the angular contact ball bearing (8) at the thinnest point is greater than the thickness of the starting material for the ramp disc (2).

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