Friction shift element for a vehicle's transmission

Abstract

Friction switching element for a transmission of a vehicle with a first friction element (1) and a second friction element (3) as friction partners, with overlapping friction surfaces that can be brought into contact with each other for torque transmission, wherein - the first or the second friction element (1, 3) has an approximately ring-shaped friction surface (7), wherein the other friction element (1, 3) has several friction surface elements (5) distributed over the circumference of an approximately ring-shaped base body of the first or second friction element (1, 3) as a corresponding friction surface, wherein the friction surface elements (5) project radially into the overlap area, - wherein both the first or second friction element (1, 3) with the approximately ring-shaped friction surface (7), the other friction element (1, 3) as well as the friction surface elements (5) are each formed in one piece, - characterized in that the first or second friction element (1, 3) and the approximately ring-shaped base body of the respective other friction element (1, 3) are radially spaced apart from each other.

Description

[0001] The present invention relates to a friction shift element for a transmission of a vehicle with a first friction element and a second friction element as friction partners, with overlapping friction surfaces which can be brought into contact with one another for torque transmission, wherein the first or the second friction element has an approximately annular friction surface, wherein the respective other friction element has, as a corresponding friction surface, a plurality of friction surface elements distributed over the circumference of an approximately annular base body of the first or second friction element, wherein the friction surface elements project radially into the overlap area.

[0002] The friction shift element, for example in a multi-disk design or the like, is provided for a transmission, in particular an automatic transmission of a vehicle. The first friction element can be assigned to a first carrier, for example an inner disk carrier or outer disk carrier. The second friction element can be assigned to a second carrier, for example an outer disk carrier or inner disk carrier. Several friction elements can form a disk pack, wherein first and second friction elements can be arranged alternately axially one behind the other and can be pressed against one another by actuation when the friction shift element is closed in order to realize the torque transmission between the packs of first and second friction elements.

[0003] For example, DE 10 2009 001 101 A1 discloses a transmission with multiple frictional shifting elements for achieving different gear ratios. The frictional shifting elements are designed as multi-plate shifting elements, with the inner and outer plates featuring frictionless friction surfaces to increase the permissible surface pressure. This allows the shifting element to be smaller while maintaining the same transmission capacity and causing lower drag torques in the open operating state.

[0004] Furthermore, DE 10 2009 027 017 A1 discloses a disk pack for a multi-disk brake or multi-disk clutch in which a spring effect is integrated into the disks, ensuring a desired spacing between the disks even when the disk pack is open. This creates a clearance throughout the entire disk pack.

[0005] From DE 103 15 169 A1 a clutch arrangement is known in which friction elements carrying friction linings and friction elements without friction linings interact and in which the friction elements carrying friction linings have a fluid surface arrangement for generating a fluid circulation flowing around the friction elements, which is predominantly realized by friction surface elements arranged distributed over the circumference of the friction element.

[0006] From GB 814 992 A a friction element is known which comprises a disc and friction linings on both sides of the disc, wherein a part of the friction lining on at least one side of the disc is connected to a spring element, wherein the friction linings are connected to a friction lining carrier of the friction element by means of an adhesive connection or by means of a rivet connection.

[0007] A disadvantage of these friction shift elements is that high drag torques can still occur. The applicant's as yet unpublished DE 10 2014 200 854 A1 shows a low-drag-torque friction shift element. This is achieved, on the one hand, by eliminating friction linings and, on the other hand, by molding the friction surface element onto the friction element, i.e., by forming it integrally. A disadvantage is the still relatively high material consumption for manufacturing friction elements of a friction shift element. Furthermore, the friction elements must be made of the same material as the friction surface elements.

[0008] Furthermore, EP 1 650 454 A1 discloses carrier plates for friction plates which are made up of several segments to reduce costs, thus resulting in less punching waste.

[0009] The present invention is based on the object of proposing a friction shift element for a vehicle transmission that can be manufactured as cost-effectively as possible, generates the lowest possible drag torque, and also consumes less material during production, thus further improving the already advantageous invention from DE 10 2014 200 854 A1. Furthermore, a further aspect of the invention is to provide a method for cost-effective and material-saving production.

[0010] According to the invention, this is achieved in that both the first or second friction element with the approximately annular friction surface, the respective other friction element and the friction surface element are each formed in one piece, and in that the first or second friction element and the approximately annular base body of the respective other friction element are radially spaced from one another.

[0011] A disadvantage of the prior art is that the friction surface elements and the approximately annular base body in integrally formed designs are necessarily made of the same material. If the material requirements in terms of optimum wear, strength, friction coefficient curve and drag torque properties were to be met, the entire plate had to be made of a high-quality material. Since the plate has a very large area compared to the friction surface, a large amount of high-quality material was required. By means of the "multi-part" design of the friction element and friction surface element, with each friction surface element being formed approximately tooth-shaped onto the annular base body of the friction element, it is possible to use different materials orMaterials can be used, in particular the material for the friction element can be of lower quality and significantly cheaper than the material for the rubbing friction surface elements.

[0012] It has also been found that, according to the inventive solution, it is possible, for example, to manufacture the inner plate from the "stamping waste" of the outer plate, since the parts do not overlap radially, i.e., there is no radial overlap between the approximately annular base body of one plate and the friction plate with the annular friction surface. Frictional contact is achieved exclusively via the friction surface elements arranged on the annular body. Thus, stamping waste can be significantly reduced, leading to significant cost savings.

[0013] The advantage of the friction surface elements that project radially into the overlap area is that the contact surface or the corresponding friction surfaces between the two friction elements is or are reduced in this way. The friction surface is interrupted several times in the circumferential direction by providing individual friction noses or friction teeth on one of the friction elements, i.e. either on the first or the second friction element. The interruptions in the circumferential direction are achieved, for example, by recesses between the provided friction surface elements or friction noses or friction teeth. Accordingly, the first and second friction elements, which can be brought into frictional engagement with one another, are spaced apart from the respective projecting friction surface elements in the radial direction to reduce the overlap area or to reduce the number of overlapping friction surfaces. This allows coolant and / or lubricant, for example oil or the like, to flow through radially almost unhindered.Furthermore, the contact area in which drag torque is generated by shearing of the coolant and lubricant is limited to a minimum.

[0014] A further advantage of the friction switching element according to the invention is that no friction lining or friction body has to be glued, riveted or otherwise fastened to a respective friction surface element, as is known, for example, in clutches from the prior art, since the friction surface element of the friction switching element according to the invention is formed in one piece.

[0015] It is known, for example, to provide so-called radially inwardly or radially outwardly projecting friction lining carriers with adhesive-mounted friction linings or with a punched hole for accommodating ceramic plates. These friction lining carriers could have a similar geometry and arrangement on the friction element as the friction surface element of the friction shift element according to the invention. However, in this case, only the friction linings or the ceramic plates acted as friction partners with a counter-plate, so that a radially inwardly or outwardly projecting friction surface element known in the prior art was always constructed in several parts, since it always had a friction lining carrier and at least one friction lining.

[0016] The term "one-piece" does not simply mean that the friction surface element is without a friction lining. It also means that the friction surface element is formed in one piece. A friction element according to the invention with a friction surface element is therefore always formed in multiple parts and not integrally, as is the case, for example, in DE102014200854, in which the friction elements are formed in one piece with the respective friction surface elements.

[0017] Preferably, within the scope of an advantageous embodiment variant of the invention, it can be provided that the friction switching element is designed as a wet-running friction switching element in which a fluid, preferably oil, for lubrication and cooling is guided through the friction element package or plate package in the region of the friction surfaces.

[0018] The proposed friction shift element can preferably be used in automatic transmissions as a disengaging shift element, since such shift elements enable full-fledged power shifts without thermal stress on the friction shift element. A disengaging shift element is characterized in that the friction shift element is closed in the lowest gear, open in the highest gear, and changes its shift state only once when sequentially shifting through all gears.

[0019] Thus, the proposed shift element results in particularly low drag torques, which significantly reduces the vehicle's fuel consumption. Furthermore, the reduced friction surfaces result in lower mass and space requirements, as well as lower manufacturing costs. Furthermore, a lower mass moment of inertia results, which allows for improved driving dynamics in a vehicle equipped with the friction shift element according to the invention in the transmission.

[0020] Furthermore, a friction switching element is preferred in which the respective other friction element has recesses and in which the friction surface elements are received in the respective recesses.

[0021] The recesses, also called joints, have a hooking or undercut, which essentially holds the friction surface element in a form-fitting manner. The design of the hooking or undercut required for this purpose is known, for example, from puzzle pieces or from the prior art. Preferably, the respective recess is designed as an interference fit. Furthermore, it is preferred that the recesses of the respective other friction element partially interrupt the approximately annular base body along its inner or outer circumference.

[0022] Furthermore, it is preferred if the friction surface element is formed onto the annular friction element via different, consecutive radii. It is particularly preferred if the recesses and their immediate surroundings define friction surface element zones, and that respective intermediate zones are arranged between circumferentially adjacent friction surface element zones, wherein the respective intermediate zone has a central zone and two transition zones enclosing the central zone, wherein the central zone is designed with a first radius R3 and the respective transition zone is designed with a radius R4, and wherein the transition zones are each tangent to a central zone and a friction surface element zone.

[0023] The radius can, for example, be larger in the area of ​​the outer circumference of the ring-shaped base body of the friction element than at the end of the tooth-shaped friction surface of the friction surface element. In this way, the transition from the cantilevered friction surface element to the base body is optimized in terms of its stress distribution. The ring cross-section increases in the direction of the friction surface element, which allows the disk pack to be constructed more radially compactly overall. Consequently, the friction surface element introduces a bending moment into the ring-shaped geometry when force is transmitted. In order to optimize the resulting stress distribution on the friction element, it is advisable to start the curvature with a larger radius, starting from the ring geometry, and to continue with a smaller radius towards the friction surface element. The geometry or radius distribution on the friction surface element is on both sides of the friction tooth orof the friction surface element 5 can be represented differently (preferred direction of rotation).

[0024] It is also preferred if the friction surface elements are fixed to the respective other friction element by means of fixing means. In particular, it is preferred if the friction surface elements are fixed to the respective other friction element by means of forming. Thus, the friction surface element can be secured in the plate, in particular against lateral, and especially axial, slipping out.

[0025] Furthermore, it is preferred if the friction surface elements are fixed to the corresponding friction element at least point by point along a joining line. The joining line is the line which, viewed from an axial perspective, limits the extent of the recess in the circumferential direction and / or in the radial direction. The friction surface elements are fastened to the approximately annular base body by forming. The joining process can take place in individual areas, i.e. point by point, of the joining line or along the entire joining line. For example, a force-fitting and form-fitting connection can be created between the friction element and the friction surface element by plastically deforming an edge area of ​​at least one of the parts. Unlike welding, different materials can be joined together. In addition, higher torques can be transmitted via caulked connections.

[0026] Furthermore, it is preferred if the friction surface elements have chamfers along the joining line. A chamfer in the area of ​​the joining line, on the thinner part, can further simplify fixation.

[0027] Furthermore, it is preferred that the friction surface elements be welded to the respective other friction element. One advantage of welding is that the form-fitting friction surface elements do not require any form-fitting fixation. In this case, a back hook or undercut is also unnecessary.

[0028] Furthermore, it is preferred if the respective other friction element has at least a first thickness in the axial direction, and if the respective friction surface element has at least a second thickness in the axial direction, wherein the at least first and the at least second thickness are unequal. It is particularly preferred for the second thickness to be smaller than the first thickness. This allows each of the components to be specifically optimized to its requirements. For example, this simplifies the fixing of the somewhat thinner friction surface element during the forming process.

[0029] It is preferred that the friction surface elements have chamfers in the direction of rotation at an inlet and / or outlet area. If the chamfers are applied at the points where the counter-plate enters and / or exits the friction zone, the drag torques can be further reduced.

[0030] It is also preferred if the friction surface elements have grooves. Suitable grooving can further significantly reduce drag torque while simultaneously increasing load capacity.

[0031] It is further preferred if the friction surface elements are made of steel. Furthermore, it is preferred if the friction surface elements are sintered. It is also preferred if the friction surface elements are made of ceramic.

[0032] According to another aspect, a method is provided, namely a method for producing a friction shift element for a transmission of a vehicle with a first friction element and a second friction element, wherein the first or the second friction element has an approximately annular friction surface, wherein the respective other friction element has an approximately annular base body, comprising the steps: - manufacturing the second friction element from a semi-finished product made of a first material in a first step, whereby a substantially cylindrical recess is formed in the semi-finished product, - manufacturing the approximately annular base body of the first friction element in a subsequent second step from the semi-finished product from the first step, wherein the manufacturing takes place essentially coaxially to the cylindrical recess, or comprehensively the steps: - manufacturing the approximately annular base body of the second friction element from a semi-finished product made of a first material in a first step, whereby a substantially cylindrical recess is created in the semi-finished product, - Manufacturing the first friction element in a subsequent second step from the semi-finished product from the first step, wherein the manufacturing takes place essentially coaxially to the cylindrical recess.

[0033] The advantage of the aforementioned process is that the first friction element, for example, an outer disc, can be manufactured coaxially with the second friction element, for example, an inner disc. In the case of a disc, only the approximately annular base body is manufactured. This allows corresponding discs to be manufactured "into each other," meaning that an inner part is not scrapped twice, as is the case with conventional disc manufacturing. In this sequence, the inner disc is, so to speak, manufactured from the material waste of the outer disc.

[0034] Furthermore, a method is preferred in which the second friction element is punched from a sheet metal strip, thereby producing punching waste, and the first friction element is punched from the punching waste.

[0035] Particularly preferred is a method in which several friction surface elements are manufactured from the first material or from a second material.

[0036] It has been discovered that different materials can be used for the friction element and the friction surface element. This can lead to significant cost reductions, as it is sufficient to manufacture only the friction surface element, which is smaller than the friction element, from a higher-quality and more expensive material.

[0037] Furthermore, a method is preferred in which a plurality of recesses are manufactured on the first or second friction element for receiving friction surface elements.

[0038] It is also preferred if the method connects the friction surface elements with that of the first or second friction element.

[0039] A method in which the friction surface elements are inserted into the recesses is particularly preferred.

[0040] Furthermore, a method is preferred in which, to fix the friction surface element to the first or second friction element, a forming process, for example, caulking, is performed on the friction surface element and / or on the first or second friction element. Furthermore, a method is preferred in which the friction surface elements are welded to the first or second friction element.

[0041] Furthermore, a method is preferred, namely a method for producing a friction shift element for a transmission of a vehicle with a first friction element and a second friction element, wherein the first or the second friction element has an approximately annular friction surface, wherein the respective other friction element has an approximately annular base body, comprising the steps: - manufacturing the first friction element from a semi-finished product made of a first material in a first step, whereby material waste is generated, - manufacturing the approximately ring-shaped base body of the second friction element from this material waste in a subsequent second step, or comprehensively the steps: - manufacturing the approximately ring-shaped base body of the first friction element from a semi-finished product made of a first material in a first step, whereby material waste is generated, - Manufacturing the second friction element from this material waste in a subsequent second step.

[0042] This process involves manufacturing in reverse order, i.e., manufacturing, particularly punching, an outer lamella from the waste material of an inner lamella. For one of the two lamellas, not the entire lamella is manufactured, but only the approximately ring-shaped base body. Following the second step, the process steps described above can be carried out in full.

[0043] A further aspect of the invention is when at least one friction element of respectively adjacent first and second friction elements is designed so as to be bevelled, conical or axially tapered in cross-section or in the axial direction on the friction surfaces facing one another. If, for example, the inner and / or outer friction elements are flattened or similarly designed, this results in axial installation space savings. Furthermore, greater strength is achieved at the same time, since the plates or friction elements are thicker or stronger in the highly loaded areas. Highly loaded areas are particularly areas where the driving teeth are provided on the friction elements. In addition, better heat dissipation results, since the friction surface elements have a larger connection to the annular cross-section of each friction element. This results in greater thermal load capacity.The conical effect also advantageously requires lower axial contact forces to close the friction shift element. Furthermore, a lower degree of deformation is required during the production of the friction shift element.

[0044] A next aspect of the invention lies in providing a forced spacing in the proposed friction switching element, whereby adjacent friction elements are kept at a distance even in the open state and have no effect in the loaded state, i.e. when the friction switching element is closed. The forced spacing can be achieved, for example, by providing at least one spring tab element or the like in the circumferential direction on at least one friction surface element that is resilient in the axial direction of the friction element. Due to this forced spacing of the friction elements in a plate pack, coolant and / or lubricant can flow radially through with lower flow resistance. This reduces the shear forces in the intermediate space and reduces the drag torque.

[0045] The friction shift element can be actuated hydraulically, pneumatically, electromechanically, or mechanically. The wet-running friction shift element is preferably actuated hydraulically, since the existing coolant and lubricant can be used as the hydraulic medium. The friction elements of the proposed friction shift element can be made of sheet metal, steel, or the like. The steel can contain carbon, for example, C15, C60, C75. The friction elements can be hardened, e.g., nitrocarburized or gas nitrided. A coating similar to synchronizers, e.g., sintered metal, molybdenum, carbon, or the like, can be provided as a coating for the friction elements. Furthermore, at least one of the friction elements can have a groove or the like, for example, a parallel groove, waffle groove, or bottleneck groove similar to paper linings.

[0046] The proposed friction shift element can be used in a powershift transmission. It is also conceivable that the friction shift element could be used in a continuously variable multi-range transmission or in an electric vehicle drive. Other possible applications include all-wheel drive decoupling, retarder decoupling, reversing groups, and range-change groups.

[0047] In addition to the friction shift element described above, the present invention also claims an automatic transmission for a vehicle with a friction shift element designed in this way.

[0048] The present invention is further explained below with reference to the drawings. They show: Fig. 1 and Fig. 2: various partial views of a friction shift element according to the invention with a friction element designed as an inner plate with several friction surface elements projecting radially outwards; Fig. 3 and Fig. 4: several partial views of the friction switching element with a friction element designed as an outer plate with several friction surface elements projecting radially inwards; Fig. 5 and Fig. 5A: several partial views of a friction surface element formed over several radii onto an inner plate; Fig. 6 and Fig. 7: several partial views of the friction switching element with rib-shaped reinforcements provided on both sides in the circumferential direction on the friction surface element; Fig. 8 to 16: various partial views of the friction switching element with spring tab elements formed circumferentially on the friction surface element for forced distancing of adjacent friction elements; Fig. 17: a schematic view of the friction switching element as a plate pack with friction elements forcibly spaced in the area of ​​the respective driving teeth by means of a spring element; Fig. 18: a schematic view of the friction switching element as a plate pack with friction elements bevelled on the corresponding friction surfaces and thus conical in shape; Fig. 19: a schematic view of the friction switching element as a plate pack with friction elements having a smaller axial thickness in the area of ​​the friction surface elements; Fig. 20: a schematic view of the friction switching element as a disk pack with friction elements having a smaller axial thickness in the area of ​​the annular friction surfaces; Fig. 21: a schematic view of the friction switching element as a plate pack with friction elements having a smaller axial thickness in the area of ​​the annular friction surfaces and in the area of ​​the friction surface element; Fig. 22 and Fig. 23: several detailed views of the friction switching element with friction surface elements having chamfers or radii in the circumferential direction at the inlet and outlet areas; Fig. 24: a schematic view of the friction switching element as a disk pack with friction elements attached to a common carrier with friction surface elements arranged congruently one behind the other in the axial direction; Fig. 25: a schematic view of a Fig. 24 shown inner friction element rotatably receiving inner disc carrier with adapted driving teeth; and Fig. 26 and Fig. 27: various schematic partial views of the friction switching element as a plate pack with a support element provided at the end of the plate pack and spaced outwards in the axial direction from the central friction surface radius; Fig. 28: shows a coaxially aligned outer / inner plate pair of a friction shift element according to the invention from an axial front view; Fig. 29: shows an enlarged section of the friction element according to the invention with inserted friction surface element; Fig. 30: shows the friction element and friction surface element of the Fig. 28 in non-inserted state; Fig. 31: shows the inserted friction surface element from Fig. 29, which is additionally fixed along a joint by means of fixing means; Fig. 32: shows the inserted friction surface element from Fig. 31 with fixing agent in a perspective view; Fig. 33: shows an enlarged section of the friction element according to the invention with welded friction surface element; Fig. 34: shows the coaxially aligned outer / inner lamella pair of Fig. 28 in a rear view; Fig. 35: shows an enlarged section of the friction surface element according to the invention from Fig. 29 with chamfers; Fig. 36: shows an inner plate 3 of the friction shift element according to the invention with radially outwardly projecting inserted friction surface elements 5; Fig. 37: shows a coaxially aligned outer / inner plate pair arrangement 1 or 3 of a friction shift element according to the invention with inserted radially outwardly projecting friction surface elements (5); Fig. 38: shows a geometry of a further preferred embodiment of the friction switching element according to the invention; Fig. 39: shows an exemplary process of a method for producing a friction switching element according to the invention with inserted friction surface elements (5); and Fig. 40: shows an exemplary process of a method for producing a friction switching element according to the invention with welded friction surface elements (5).

[0049] In Fig. 1 to 27, various embodiments of a friction shift element according to the invention for a transmission of a vehicle are shown by way of example as a multi-disk shift element.

[0050] The friction shift element comprises a plurality of first friction elements 1, which are non-rotatably mounted on a first carrier 2, and a plurality of second friction elements 3, which are non-rotatably mounted on a second carrier 4. The first and second friction elements 1, 3 are arranged alternately one behind the other as a disk pack, so that overlapping friction surfaces are formed between a first friction element 1 and a second friction element 2. For torque transmission, the friction elements 1 and 3 are pressed axially together.

[0051] The first or second friction elements 1, 3 each have an approximately annular friction surface, wherein the respective other friction elements 1, 3 have, as a corresponding friction surface, several radial friction surface elements 5 projecting in the overlap area.

[0052] In the Fig. 1 and Fig. 2, a variant is provided in which the first friction elements 1 are designed as outer plates and the second friction elements 3 as inner plates, wherein the outer plate, which is each approximately annular, has an outer driving toothing 6 for connecting to the outer plate carrier 2 and an approximately annular friction surface 7. The inner plate, i.e. the second friction element 3, has an inner driving toothing 8 for connecting to the inner plate carrier 4 and a plurality of friction surface elements 5 distributed radially outwardly over the circumference and overlapping with the annular friction surface 7 of the outer plate.

[0053] In the Fig. 3 and Fig. 4 are in contrast to the version shown in the Fig. 1 and Fig. 2, the friction surface elements 5 are provided on the first friction element 1, which is provided as outer plates, and the annular friction surface 7 is provided on the second friction element 3, which is designed as inner plates. The friction surface elements 5 are distributed over the circumference, projecting radially inward and overlapping with the annular friction surface 7. Fig. 2 and Fig. The arrows on the plate packs shown in Figure 4 illustrate the axial forces acting to close the friction shift element according to the invention.

[0054] Regardless of the two versions according to Fig. 1 to 4, it is provided that the first and second friction elements 1, 3, which can be brought into frictional engagement with one another, are spaced apart from one another in the radial direction, apart from the projecting friction surface elements 5.

[0055] The Fig. The friction surface elements 5 shown in Figures 1 to 27 are welded to the first or second friction elements 1, 3, so that several separate tooth-shaped friction or contact surfaces are provided in the circumferential direction, which, when the friction switching element is closed, can be brought into contact with the approximately annular friction surface 7. The friction surface elements 5 can be optimized with regard to length and width ratio, angle, edge shape, and surface structure in order to create a friction switching element that can be produced as cost-effectively as possible and has a low drag torque.

[0056] Fig. 5 and Fig. 5A show detailed views of the friction surface element 5 welded to the base body of the second friction element 3 based on the embodiment variant according to Fig. 1 and Fig. 2. To increase the mechanical strength of the friction element 3, which is constructed in several parts with the friction surface element 5, the ring cross-section is enlarged in the direction of the friction surface element 5. This means that in the Fig. 5 and Fig. 5A, the outer circumference of the approximately annular friction element 3 is enlarged in the area of ​​the molded friction surface element 5. In Fig. 5A, the tooth-shaped friction surface element 5 is integrally formed with the annular friction element 3 via different, consecutive radii R1, R2. The radius in the area of ​​the outer circumference of the annular base body of the friction element 3 is larger than at the end of the tooth-shaped friction surface of the friction surface element 5. In this way, the transition from the projecting friction surface element 5 to the base body is optimized with regard to its stress distribution. The ring cross-section increases in the direction of the friction surface element 5, allowing the disk pack to be constructed with a more radially compact design overall. Consequently, the friction surface element 5 introduces a bending moment into the annular geometry during power transmission.In order to optimize the resulting stress distribution on the friction element 3, it is advisable to begin the curvature, starting from the ring geometry, with a larger radius R1 (long arrow) and continue with a smaller radius R2 (short arrow) in the direction of the friction surface element 5. The geometry or radius distribution on the friction surface element 5 can be represented differently on the two sides of the friction tooth or the friction surface element 5 (preferred direction of rotation).

[0057] In Fig. 6 is a side view of the friction switching element, in which Fig. 7 shows a view taken along section line VII of VII. In the embodiment shown, a rib-shaped reinforcement 9 is formed on both sides of the friction surface element 5 in the circumferential direction. Adjacent to the area of ​​the outwardly projecting friction surface element 5 there is thus an area with reduced plate width or thickness in order to increase strength without enlarging the friction surface of the friction surface element 5. The reduced plate width can be created, for example, as a bevel next to the actual friction surfaces of the friction surface element 5 by forming technology. The rib thus formed mechanically supports the friction surface element 5. This increase in strength allows the plate pack to be designed to be more compact. This is also cost-effective and increases the material strength or work hardening.

[0058] In Fig. 8 shows a plan view of a friction element 1, 3 provided with the friction surface element 5, wherein a spring tab element 10 and 10A is provided in the circumferential direction on both sides of the friction surface element 5 for forced spacing.

[0059] As is particularly evident from Fig. 8, 10, 12 to 15, the spring tab elements 10, 10A are designed to be resilient in the axial direction of the respective friction element 1, 3 and, in the unactuated state of the friction switching element, protrude in the axial direction from the friction surfaces of the friction element 1 or 3. Preferably, the spring tab elements 10, 10A are designed as one piece with the friction surface element 5, as can be seen in particular from the Fig. 9, Fig. 11, Fig. 14 and Fig. 16 is evident.

[0060] Preferably, the spring tab elements 10, 10A are arranged on each friction surface element 5 in the axial direction opposite to the respective friction element 1, 3. In a disk pack consisting of several friction elements 1, 3, as in particular in Fig. 10 and Fig. 15, the spring tab elements 10, 10A on a friction element 1 or 3 act axially opposite to adjacent friction elements 1 or 3 of the same disk carrier 2 or 4. The friction switching element is in the Fig. 10 and Fig. 15 is open, meaning that the plates or friction elements 1, 3 are in the released state. It can be seen how the spring-loaded elements 10, 10A keep adjacent friction elements 1 at a distance. This ensured distance reduces the shearing of the coolant and lubricating oil flowing through the gap, thus generating less drag torque.

[0061] Regardless of the respective design of the spring-loaded link elements 10, 10A, adjacent friction elements 1, 3 are kept at a distance. In the loaded state, i.e. when the friction switching element is closed, the spring-loaded link elements 10, 10A are pressed together or apart, and the actual friction surfaces come into contact. To ensure particularly effective forced spacing, it is expedient to make the spring-loaded link elements 10, 10A thinner than the friction elements 1, 3 or friction surface elements 5. Ideally, several such spring-loaded link elements 10, 10A are arranged distributed over the circumference to achieve proper separation of the friction elements 1, 3 in the released state. The spring-loaded link elements 10, 10A do not necessarily have to be attached to the friction surface elements 5, as shown here. Drivers or the like specifically designed to hold the spring-loaded link elements 10, 10A can also be used.In this case, the holder for the spring tab elements 10, 10A is also thinner than the rest of the friction element 1, 3.

[0062] The design clearance of the entire plate pack can be greater than the sum of the spring travels of the individual friction elements 1, 3. This means that when the friction switching element is open, the spring-loaded elements 10, 10A can certainly lift off, i.e., they do not necessarily have to rub. This is particularly relevant when the spring-loaded elements 10, 10A operate at differential speeds, i.e., when they act on friction elements 1, 3 of different carriers 2, 4. For example, in Fig. 12, Fig. 14, Fig. 15 and Fig. 16, the friction element 3 is shown as a lining plate with a friction lining, for example a paper lining or the like. In contrast, in Fig. 13 the friction element 3 is shown without friction lining.

[0063] Another possibility of forced distancing is in Fig. 17. In this embodiment, the friction elements 1, 3 of the same plate carrier 2, 4 are forcibly spaced apart in the area of ​​the respective driving teeth 6, 8 by means of individual spring elements 11, 12. The spring elements 11, 12 are only indicated, but can also be designed as spring plates or the like, not just springs. The spring elements 11, 12 act on plates or friction elements 1, 3 which are assigned, for example, to the same plate carrier 2, 4. Thus, there is no difference in speed between the friction elements 1, 3. With the help of the spring elements 11, 12, the friction elements 1, 3 of the respective carrier 2, 4 are spaced apart from one another, and the friction elements 1, 3 of the different carriers 2, 4 are only spaced apart from one another at two friction points. This ensures that a defined air gap is provided and that only negligible drag torques occur when the switching element is open. Fig. In the embodiment shown in Figure 17, the disk pack consisting of inner and outer disks is thus centrally aligned with each other.

[0064] In the Fig. Figures 18 to 21 show various designs of the friction shift element, which enable greater mechanical strength and a reduction in axial installation space. Furthermore, improved heat dissipation and a lower axial contact force are achieved, and a lower degree of deformation of the friction elements 1, 3 during production is also possible.

[0065] In Fig. Figure 18 shows a friction shift element in which adjacent first and second friction elements 1, 3 are chamfered or conical in cross-section at the mutually facing friction surfaces. In particular, the conical effect requires lower axial contact forces. In this design, the axial taper of the friction surface elements 5 and the friction surfaces 7 is symmetrical. Asymmetrical or one-sided flattening is also possible.

[0066] In Fig. Figure 19 shows a friction shift element in which the friction surface element 5 has a smaller thickness in the axial direction than in the area of ​​the driving teeth 8 of the second friction element 3. In this design, the taper of the friction surface elements 5 is symmetrical. An asymmetric or one-sided flattening is also possible.

[0067] Fig. Figure 20 shows the friction shift element in which the first friction elements 1 have a smaller thickness in the axial direction in the region of the annular friction surfaces 7 than in the region of the driving teeth 6, with the friction surface elements 5 remaining unchanged in terms of their thickness. In this embodiment, the tapering of the annular friction surfaces 7 is symmetrical. It is also possible to provide an asymmetrical or one-sided flattening.

[0068] In Fig. 21 shows an embodiment in which the Fig. 19 and Fig. 20 versions shown can be combined with each other.

[0069] In the Fig. 22 and Fig. Figure 23 shows various detailed views of the friction shift element, in which chamfers or radii are provided on the friction surface element 5 in the circumferential direction at the inlet and outlet areas. The friction surface elements 5 or friction teeth thus have chamfers or radii in their inlet and outlet areas to protect the adjacent friction element. This prevents the friction surface element 5 from sliding over the friction partner, almost like a turning tool, in a cutting action. Furthermore, drag torques can be reduced as a result.

[0070] Fig. Figure 24 shows the proposed friction shift element with an assembly aid, in which the friction surface elements 5 on the friction elements 3 of the inner plate carrier 4 are arranged congruently one behind the other in the axial direction. When assembling the friction elements 1 and 3, it is important to ensure that the friction surface elements 5 or teeth are arranged one behind the other in the axial direction. For this reason, the friction elements 1, 3 have driving teeth 6, 8 with different geometries on individual teeth or tooth gaps. An assembly device corresponding to the driving teeth 3 can now ensure assembly in the desired rotational position. In this illustration, the friction elements 1, 3 are also designed with reversal symmetry. Reversal symmetry means that it is irrelevant which side faces up and which side faces down during assembly. This reduces the possibility of incorrect assembly.

[0071] Within the driving toothing 6, 8, different geometries, such as different tooth widths and / or different tooth gap widths and / or different tooth angles, are provided in order to force, in combination with a corresponding carrier 2, 4, an assembly with friction surface elements 5 arranged congruently one above the other in the axial direction.

[0072] As in Fig. As shown in Figure 25, the disk carrier 4 has the geometry matching the friction element 3 in its driving toothing 15, so that assembly at an incorrect angle of rotation is excluded.

[0073] In the Fig. 26 and Fig. 27 shows the proposed friction switching element with corresponding disk pack, consisting of first friction elements 1 and second friction elements 3, wherein the disk pack in Fig. 26 is ventilated or open and in Fig. 27 is closed or switched. The piston 13 for actuating the friction switching element and for applying the necessary axial force is actuated accordingly, so that the axial force is applied to the disk pack. The force is guided through the disk pack and fed back to the disk carrier 2 at the last friction element 1. As a result, the last friction element 1 is displaced. In order to achieve a uniform contact pattern on the friction surfaces independently of the displacement, it is proposed that at least one support element 14 is provided at the beginning and / or end, in the illustration according to Fig. 26 and Fig. 27, is arranged at the end of the friction element package or plate package and is spaced outwards or inwards from the mean friction surface radius of the corresponding friction surfaces of the friction elements, in the embodiments shown outwards in the axial direction.

[0074] In the Fig. Figures 28 to 38 illustrate further various embodiments of the friction shift element according to the invention. In particular, they show enlarged views of the friction elements and friction surface elements of the friction shift element according to the invention.

[0075] Fig. Figure 28 shows a coaxially aligned outer / inner plate pair 1 and 3, respectively. Nine friction surface elements 5 are inserted into corresponding joints 16 along a joint line 17 and project radially inward into the overlap area. The joint line 17 defines the circumferential and radial boundaries of the joint 16.

[0076] Of course, any other number of friction surface elements is also possible. Furthermore, the shape of the friction surface elements (length / width ratio, angle, edge shape, surface structure) can be freely optimized.

[0077] Fig. Figure 29 shows an enlarged section of a friction element 1 with an inserted friction surface element 5 of the friction shift element according to the invention. A back-hook 18 essentially holds the friction surface element in a form-fitting manner along the joining line 17, as is known, for example, from puzzle pieces.

[0078] Fig. 30 shows the friction element and friction surface element of the Fig. 29 in non-inserted state.

[0079] Fig. 31 shows the inserted friction surface element 5 from Fig. 29, which is additionally fixed to the joint 16 by means of four fixing means 19. A forming process has been carried out at four points along the joint line 17 either on the friction element 1 and / or on the friction surface element 5 in order to secure the friction surface elements 5 against falling out laterally.

[0080] Fig. 32 shows the inserted friction surface element from Fig. 31 in a perspective view. The friction surface element 5 has a thinner thickness D2 than the outer plate 1, which has a thickness D1. This simplifies fixation during the forming process. The forming is shown here only pointwise, i.e., locally, but could equally well occur along the entire joining line.

[0081] Fig. 33 shows an enlarged section of the friction element of the friction switching element according to the invention with welded friction surface element 5. The rear hook 18 can then be omitted.

[0082] Fig. 34 shows the coaxially aligned outer / inner lamella pair 1 and 3 respectively from Fig. 28 in a rear view, but without the friction surface elements 5. It is clearly visible how the annular base bodies of the two plates 1, 3 are radially spaced from each other. This also shows how the inner plate 3 can be manufactured coaxially with the outer plate 1, for example, using combination punching. Thus, an inner part does not have to be scrapped twice. The friction surface elements 5 can be joined into the joints 16.

[0083] Fig. 35 shows an enlarged section of the friction surface element according to the invention from Fig. 29 with chamfers. These are milled into the entry and / or exit zones. This further reduces drag torque.

[0084] Fig. 36 shows an inner plate 3 of the friction shift element according to the invention with radially outwardly projecting friction surface elements 5, which are inserted and not welded.

[0085] Fig. 37 shows a coaxially aligned outer / inner plate pair arrangement 1 or 3 with as in Fig. 1 radially outwardly projecting friction surface elements 5, whereby in contrast to Fig. 1 the friction surface elements 5 are inserted and not welded.

[0086] In Fig. 38 shows the geometry of a preferred embodiment. Here, the recesses, i.e., the joints 16, and their immediate surroundings define friction surface element zones 25. Between circumferentially adjacent friction surface element zones 25, respective intermediate zones 22 are arranged, wherein the respective intermediate zone 22 has a central zone 24 and two transition zones 23 enclosing the central zone 24, wherein the central zone 24 is designed with a radius R3 and the respective transition zone 23 is designed with a radius R4, and wherein the transition zones 23 each come into a tangent with a central zone 24 and a friction surface element zone 25.

[0087] In this way, the transition of the projecting friction surface element 5 to the base body is similar in terms of its stress distribution as already shown in Fig. 5a shown, optimized.

[0088] The Fig. 39 (with inserted friction surface elements 5) and 40 (with welded friction surface elements 5) show an exemplary process of a method for producing a friction switching element according to the invention with a first and second friction element, wherein the friction element 3 is the friction element that receives the friction surface elements 5.

[0089] In Fig. 39, in a first step 110, a friction element 3 designed as an inner plate is punched from a sheet metal strip - punching waste 26 is created, i.e. a sheet metal strip with a hole-shaped recess. In a subsequent second step 120, a friction element 1 designed as an outer plate is punched from the punching waste 26, the outer plate 1 being punched coaxially to the hole-shaped recess. In a subsequent step 130, the recesses 16 designed as joining points are punched into the inner plate with back hooks. In a subsequent step 131, the friction surface elements 5 designed as friction teeth are produced. The friction teeth can be punched from further punching waste 27 or from a different material. In a next step 132, the friction teeth 5 are inserted into the joining points 16.In a subsequent step 133, the friction teeth 5 are fixed to the inner plate 3 in the area of ​​the joining line 16 by means of caulking, so that a permanent force- and form-fitting connection is created.

[0090] For the expert it is clear that this Fig. The method shown in Figure 39 represents only one exemplary method. Of course, additional manufacturing steps or even fewer steps are conceivable, for example, steps for manufacturing the driving teeth or, for example, because certain steps can take place simultaneously. Thus, it is particularly conceivable to perform steps 110 and 130 simultaneously. The recesses 16 can also be punched into the outer plate. Accordingly, the friction teeth 5 would then project radially inward. It is also conceivable to punch the outer plate first and then the inner plate.

[0091] Steps 110, 120 of the Fig. 40 are identical to those in Fig. 39. In a step 140 following step 120, recesses 16 without back hooks are punched into the inner plate. Subsequently, in a subsequent step 141, the friction teeth 5 are manufactured. Subsequently, in a step 142, the friction teeth 5 are welded to the recesses 16 provided for them.

[0092] Here too, it is clear to the expert that the Fig. The process shown in Figure 40 is only an example. Of course, further steps, such as steps for manufacturing the drive teeth, or even fewer manufacturing steps are conceivable. The friction teeth can also be welded to recesses punched into the outer plate 1, so that they then project radially inward. It is also conceivable to punch the outer plate first and then the inner plate. Further exemplary embodiments of the invention are:

[0093] Friction shift element for a transmission of a vehicle, with at least one first friction element 1 assigned to a first carrier 2 and with at least one second friction element 3 assigned to a second carrier 4 as friction partners with overlapping friction surfaces which can be brought into contact with one another for torque transmission, wherein the first or the second friction element 1, 3 has an approximately annular friction surface 7, characterized in that the respective other friction element 1, 3 has at least one friction surface element 5 projecting approximately radially into the overlap region as a corresponding friction surface.

[0094] Friction switching element, wherein the first and second friction elements 1, 3, which can be brought into frictional engagement with one another, are spaced apart from one another in the radial direction, apart from the at least one projecting friction surface element 5.

[0095] Friction switching element, wherein several friction surface elements 5 are arranged distributed over the circumference of an approximately annular base body of the first or second friction element 1, 3.

[0096] Friction switching element, wherein the friction surface element 5 is integrally formed on the first or second friction element 1, 3.

[0097] Friction shift element, wherein the first friction element 1 is designed as an outer plate and the second friction element 3 is designed as an inner plate, wherein the approximately annular outer plate has an outer driving toothing 6 for connecting to the outer plate carrier 2 and an approximately annular friction surface 7 and wherein the inner plate has an inner driving toothing 8 for connecting to the inner plate carrier 4 and a plurality of friction surface elements 5 distributed radially outwards and overlapping with the annular friction surface 7 of the outer plate.

[0098] Friction shift element, wherein the first friction element 1 is designed as an outer plate and the second friction element 3 is designed as an inner plate, wherein the approximately annular inner plate has an inner driving toothing 8 for connecting to the inner plate carrier 4 and an approximately annular friction surface 7 and wherein the outer plate has an outer driving toothing 6 for connecting to the outer plate carrier 2 and a plurality of friction surface elements 5 distributed radially inwardly over the circumference and overlapping with the annular friction surface 7 of the inner plate.

[0099] Friction switching element, wherein each friction surface element 5 is formed approximately tooth-shaped onto the annular base body of the friction element 1, 3.

[0100] Friction switching element, wherein the tooth-shaped friction surface element (5) is formed onto the annular friction element 1, 3 via different radii R1, R2 lying one behind the other.

[0101] Friction switching element, wherein the radius R1 in the area of ​​the inner or outer circumference of the annular base body is larger than the radius R2 in the area of ​​the tooth-shaped friction surface of the friction surface element 5.

[0102] Friction switching element, wherein a rib-shaped reinforcement 9 is formed on both sides of the friction surface element 5 in the circumferential direction.

[0103] Friction switching element, wherein at least one spring tab element 10, 10A is provided on at least one friction surface element 5 in the circumferential direction, which is resilient in the axial direction of the friction element 1, 3, for forced distancing of friction elements 1, 3 in the unactuated state of the friction switching element.

[0104] Friction switching element, wherein the spring tab element 10, 10A is designed as one piece with the friction surface element 5.

[0105] Friction switching element, wherein spring tab elements 10, 10A are provided on both sides in the circumferential direction on at least one friction surface element 5.

[0106] Friction switching element, wherein the spring tab elements 10, 10A are arranged protruding in the axial direction opposite to the respective friction element 1, 3.

[0107] Friction switching element, wherein the spring tab elements 10, 10A on a friction element 1, 3 act in opposite directions on adjacent friction elements 1, 3 of the same carrier 2, 4.

[0108] Friction switching element, wherein friction elements 1, 3 of the same carrier 2, 4 are forcibly spaced in the area of ​​the respective driving teeth 6, 8 via spring elements.

[0109] Friction switching element, wherein adjacent first and second friction elements 1, 3 are bevelled or conical in the axial direction on the mutually facing friction surfaces.

[0110] Friction switching element, wherein the friction surface element 5 has a smaller thickness in the axial direction than in the area of ​​the driving teeth 6, 8 of the respective friction element 1, 3.

[0111] Friction switching element, wherein the friction element 1, 3 has a smaller thickness in the axial direction in the area of ​​the annular friction surface 7 than in the area of ​​the driving teeth 6, 8.

[0112] Friction switching element, wherein chamfers or radii are provided on the friction surface element 5 in the circumferential direction at the inlet and / or outlet area.

[0113] Friction switching element, wherein the friction surface elements 5 of the friction elements 1, 3 of a common carrier 2, 4 are arranged congruently one behind the other in the axial direction.

[0114] Friction switching element, wherein within a driving toothing 6, 8, 15 different tooth widths and / or different tooth gap widths and / or different tooth angles are provided as an assembly aid for the axially congruent arrangement of the friction surface elements 5.

[0115] Friction switching element, whereby each friction element 1, 3 is designed with reversal symmetry.

[0116] Friction shift element, wherein at least one support element 14 is arranged axially at the beginning and / or end of the disk pack and is spaced outwards or inwards in the axial direction from the mean friction surface radius of the corresponding friction surfaces of the friction elements 1, 3 of the disk pack.

[0117] Friction shift element, wherein a wet-running friction shift element is provided.

[0118] Friction switching element, wherein at least one of the first and / or second friction elements 1, 3 has at least one groove in the region of the friction surface 7 and / or in the region of the friction surface element 5.

[0119] Friction switching element, wherein the friction elements 1, 3 consist of hardened steel and / or nitrocarburized steel.

[0120] Friction shift element, wherein the friction shift element is used as a disengaging shift element in an automatic transmission. Reference symbol 1 first friction element or plate, outer plate 2 first carrier 3 second friction element or plate, inner plate 4 second carrier 5 Friction surface element, friction tooth 6 Driving teeth of the first friction element 7 annular friction surface 8 Driving teeth of the second friction element 9 rib-shaped reinforcement 10.10A spring tab element 11 Spring element 12 spring element 13 pistons 14 Support element 15 Driving teeth of the second carrier 16 Recess, joint 17 Joining line 18 Underhooking, undercut 19 Fixatives 20 Weld seam 21 chamfers 22 Intermediate zone 23 Transition zone 24 Middle zone 25 Friction surface element zone 26 Punching waste 27 additional punching waste 110 Punching friction element 3 120 punching friction element 1 130 Punching of joints 16 with back hook 18 131 Punching the friction teeth 5 132 Joining the friction teeth 5 into the joints 16 133 Fixing by caulking 140 punching of joints 16 without back hooking 141 Punching of friction surface elements 5 142 Welding of the friction teeth 5 D1 first thickness, friction element D2 second thickness, friction surface element R1,R2 radius R3 radius middle zone R4 radius transition zone

Claims

[1] Friction shift element for a transmission of a vehicle with a first friction element (1) and a second friction element (3) as friction partners, with overlapping friction surfaces which can be brought into contact with each other for torque transmission, wherein - the first or the second friction element (1, 3) has an approximately annular friction surface (7), wherein the respective other friction element (1, 3) has, as a corresponding friction surface, a plurality of friction surface elements (5) distributed over the circumference of an approximately annular base body of the first or second friction element (1, 3), wherein the friction surface elements (5) project radially into the overlap area, - wherein both the first or second friction element (1, 3) with the approximately annular friction surface (7), the other friction element (1, 3) and the friction surface elements (5) are each formed in one piece, - characterized bythat the first or second friction element (1, 3) and the approximately annular base body of the other friction element (1, 3) are radially spaced from one another. [2] Friction switching element according to claim 1, characterized by that the respective other friction element (1, 3) has recesses (16) and that the friction surface elements (5) are received in the respective recesses (16). [3] Friction switching element according to claim 1 or 2, characterized by that the recesses (16) of the other friction element (1, 3) partially interrupt the approximately annular base body along its inner circumference or outer circumference. [4] Friction switching element according to one of the preceding claims, characterized by that the friction surface element (5) is formed onto the annular friction element (1, 3) via different radii (R1, R2) lying one behind the other. [5] Friction switching element according to one of the preceding claims, characterized bythat the friction surface elements (5) are fixed to the respective other friction element (1, 3) by means of fixing means. [6] Friction switching element according to claim 5, characterized by that the friction surface elements (5) are fixed to the corresponding friction element (1,3) at least pointwise along a joining line (17). [7] Friction switching element according to one of the preceding claims, characterized by that the friction surface elements (5) are welded to the respective other friction element (1, 3). [8] Friction switching element according to one of the preceding claims, characterized by that the respective other friction element (1, 3) has at least a first thickness D1 in the axial direction and that the respective friction surface element (5) has at least a second thickness D2 in the axial direction, wherein the at least first and the at least second thickness D1 and D2 are unequal. [9] Friction switching element according to one of the preceding claims, characterized bythat the friction surface elements (5) have chamfers in the direction of rotation at an inlet and / or at an outlet area.

Images