DE3609879A1 - Friction ring for clutches or brakes, method and apparatus for the production of the friction ring - Google Patents

Abstract

A friction ring for clutches or brakes consists of an annular body (1) of metal with at least one cylindrical or tapered friction face (2), which has a scatter-sintered friction facing (3). The friction facings (3) are sintered directly onto the annular body (1) itself, the initially flat friction faces (2) being formed by embossing or deep-drawing to give the cylindrical or tapered shape after the application of the scatter-sintered friction facings (3). The production method consists in that a flat annular body (1) is first of all produced, whereupon this is provided on one or both sides with a scatter-sintered friction facing (3) and then formed into a cylindrical or tapered shape together with the friction facings applied by sintering. For forming use is made of a forming tool with a die (9) and a punch (10) which acts on the annular body (1). In order to prevent negative effects on the porous scatter-sintered friction facing (3) during the forming process, a plastic film (14) is placed between the punch (10) and the annular body (1). Alternatively, the forming surface (12) of the punch (10) can also be provided with a plastic insert (17), or rounded strips (18) can be provided on the forming surface (13). <IMAGE>

Description

The invention relates to a friction ring for Clutches or brakes made of a ring body made of metal with at least one cylindrical or conical friction surface consists of a sintered friction lining. Farther The invention relates to a method and Device for producing such friction rings. These friction rings can be used in general in clutches and brakes e.g. in cone or centrifugal clutches as well as in Synchronizations for manual transmissions and the like

Scatter sintered friction linings have been around for a long time Clutches and brakes successfully applied because they are good Have rubbing properties, durable and temperature resistant are and relatively simple ge with great accuracy can be manufactured. The Sin Sprinkle the powdered powder on a flat support plate and then connect ßend sintered, whereby by one or more compression ten reached the required material density and the ge desired calibrated thickness is produced. After this Processed flat slats have been particularly in lubricated multi-plate clutches and brakes of their kind, e.g. also in automatic gearboxes from Motor vehicles and other work machines of all kinds lasts.  

From DE-PS 34 17 813 it is known at one Friction clutch or brake, especially a synchronizer device, with non-flat friction surfaces a separately ge manufactured to use friction body made of a carrier plate exists on which a scattered sintered friction lining and sintered is compressed by pressing the friction body. This separately Manufactured friction body is not on the base body with the soldered, welded or on the flat friction surface Friction surface secured in a different way. Before that the separately manufactured friction body at least approximately in brought the shape of the friction surface and included by means of rollers embossing rollers, frictional and at least in partial form finally applied to the base body. This well-known Friction ring is thus composed of individual parts, so that the manufacturing tolerances add up, which relates to the Installation conditions and adversely affect the function can. In addition, the application, the appropriate shaping and the durable fastening of the separately manufactured friction bodies relatively complex on the non-flat friction surfaces. It requires special manufacturing accuracy and care.

Another friction ring with a sintered friction lining is known from GB-PS 13 25 304. There is a cylindrical one shaped brake band open at a peripheral point with a Brake pad provided, which is made of a flexible steel sheet Carrier with a scattered sintered friction lining applied to it exists and attached to the brake band by spot welding is. This known design also uses one separately manufactured friction body and thus largely agrees with the  described from DE-PS 34 17 813 friction clutch or Brake match, the same during manufacture Effort and the same care are required.

With the brake band according to GB-PS 13 25 304 the litter can sintered friction lining on the carrier plate either as a continuous Liche layer are applied, or as one another separate sections of sintered friction material. These Sections can easily be made during the sintering process be made curved, so that the cylindrical Verfor of the entire friction lining when applied to the brake band can be made without difficulty. Also from the US-PS 27 93 427 it is in a separately manufactured Friction body known for the same purpose, in that on a Trä Scatter sintered friction lining already applied to the Making the same notches, e.g. by using a ribbed compaction stamp, where also divided into sections by the friction lining is, so that a subsequent deformation of the friction lining a non-flat friction surface is facilitated.

DE-AS 34 12 779 is finally a method for producing a synchronizer ring from a composite plant Known material, the metallic cone forming the friction cone Layer cohesively with another material formed support layer is connected. In this well-known Processes are made from a composite of steel strip Aluminum alloy is first punched out and then then by non-cutting shaping, for example by pre gene, deep drawing or the like, deformed into synchronizer rings. Here  no sintered friction lining is provided. The friction lining be is rather made of an aluminum alloy that with the supporting part forming ring body as a composite is summarized. This composite material is machined into the Shape of the friction ring forming the synchronizer ring with cylindrical brought shear or conical friction surface.

The invention is based on the task that was known ten friction rings of the type mentioned and their manufacture finally to simplify the device used for this Chen and improve that friction rings of any shape be produced with non-flat scatter sintered friction linings can, without having to produce separately made friction on the friction surfaces body must be applied.

According to the invention, this object is achieved in that the friction linings on at least one cylindrical or coni rule the friction surface of the ring body itself immediately are sintered and the initially flat friction surfaces after opening bring the sintered friction linings through non-cutting shaping, e.g. Embossing, deep drawing or the like., The ring body in the zy lindrical or conical shape. With such a thing Trained friction ring eliminates the need for friction bodies Manufacture separately, deform and on a base body to fix. The directly on the ring body ter scattered sintered friction linings form egg together with this a homogeneous machine part that is simple and precise can be characterized, is characterized by long life and both brakes, clutches and synchronizers tions can be applied advantageously.  

In the previously known versions were only on Carrier sheets applied, separately manufactured Steusinter- Friction pads deformed and then together with the Trä Gerblech applied as a separate friction body on friction rings. Just Friction rings without scatter sintered friction linings were cylindrical or deformed conically. The invention advances this state of the art opposite from the knowledge that even a chipless Deformation of scattered sintered friction linings, ver relatively massive friction bodies is possible if at Manufacturing is done with care, so that the litter sintered friction linings by directly attacking them Tools not damaged, disadvantageously compressed or de be formed. The invention makes use of this knowledge Use, differs from the previously known Executions and is therefore not easily from the State of the art derivable.

The inventive method for producing a Friction rings is through the following process steps marked .:

• - Manufacture of a ring body made of metal, preferably by punching that on top and / or on provide a flat friction surface on its underside is
• - Applying a sintered friction lining to the front seen flat friction surfaces, including Vorver tight and, if necessary, simultaneous pressing a creasing,
• - reshaping the sintered ring body by stamping,  Deep drawing or the like in a form in which the besin tert friction surfaces are cylindrical and conical, and
• - Calibration and final compression of the friction lining.

With this manufacturing process, friction rings that are on provided with sintered coverings on one or both sides are practically in one after their sintering Process step are brought into their final form. As the has shown practical experience, thereby comes as a surprise the way no unacceptable compression of the porous litter sintered layers, not even in the area of the edges of the Friction linings. By final calibration and final compression can even further improve the properties th of the friction lining can be achieved. This calibration and Final compaction can only be achieved by reshaping the besinter th ring body in one operation.

In a further embodiment of the Ver can already drive when manufacturing the ring body Apply the scattered sintered friction lining on the outer edge or on the inner edge of the same cam or groove as a driver be formed. These drivers can continue axially run to the surface line or radially outwards or inwards protrude. The carriers are already advantageous as ent speaking profile provided on the flat steel base and included in the forming process after the sintering. They can be milled, punched or embossed.

Another way of training the drivers in the context of the invention is that after the forming of the sintered ring body welded to this driver  will. This training is especially advantageous if the drivers are unfavorably formed or if different material properties between the Basic body of the friction ring and the drivers who desired the.

Another variant for the production of a friction ring according to the invention consists of the following process steps ten:

• - Make one on at least one side with one Scatter-sintered friction lining provided flat steel plate,
• - Cut a strip from the sintered Plate,
• - Bending the strip into a cylindrical or ko African closed ring bodies and
• - Welding the abutting joints of the ring body.

This type of production has the advantage that a deforma tion of the scattered sintered friction lining are largely dispensed with can. For the production of a cylindrical friction ring ge it is enough to simply bend one on one side or on Rectangular metal strip sintered on both sides. If the metal strip is curved in its plane, e.g. after one A conical friction ring can result from this be bent together. The one brought into the desired shape The friction ring can then be calibrated. This Her positioning method is particularly suitable for brittle scatter Friction linings are advantageously suitable. Can on the finished ring projecting axially or transversely to the ring axis welded will.  

The inventive device for reshaping the sintered ring body consists of a forming tool with a die and an associated stamp. According to the invention is between the ring body and the on a friction lining gripping form surface of the stamp and possibly also the An intermediate layer made of flexible material such as rubber or plastic provided. Through this measure, a uniform loading of the sintered friction lining when moving Form the ring body reached so that no uneven Compression and no damage to the friction lining occurs. In particular, also in the area of the edges of the friction lining cause no adverse changes.

The intermediate layer made of flexible material consists of a preferred embodiment of the invention direction from a film between the ring body and the is inserted on this attacking forming tool. These Foil, suitably made of plastic, equalizes pressure differences from, which due to the geometric shape and An order between the surface of the friction lining and the Form surface of the forming tool or during Deformation occur itself. In any case, it will a simple way of safely reshaping the sintered Ring body allows. The film can be used as an endless band Rolls to be fed to the forming tool, whereby they each Step according to the size of the deformed ring body wisely moved on, e.g. on a take-up reel, is wound up.

The intermediate layer made of resilient material can  a further feature of the invention but also as in the Shaped surface of the stamp and / or the die provided Use trained. Even with this measure Damage to the scattered sintered friction lining when the sintered ring body avoided. The use is expedient exchangeable so that it can be exchanged if it is damaged or due to the material together setting the scattered sintered friction lining an application with others Properties, e.g. in terms of elasticity is.

In the context of the invention has another Vorrich device for reshaping the sintered ring body as advantageous proven that the molding surface of the stamp and / or the die with protruding protruding bars is provided, which may have a rounded profile. When reshaping the sintered ring body, they come first Last the mold in contact with the sintered coating, the sinter coating is more compacted at these points. However, this only creates grooves that are in operation of the friction ring are useful rather than disadvantageous. The rub The covering between the grooves, however, remains unchanged, so that there is neither damage nor unfavorable Compression comes. So it is with this device too a perfect reshaping of the sintered ring body possible Lich, without adversely affecting the scattered sintered friction lining rivers.

With a friction lining with grooves or grooves, the protruding ledges can be arranged so that they fit into the grooves  or engage grooves. This measure also has the purpose damage to the friction lining due to the forming process avoid. The strips are expediently narrower than that Grooves or grooves in the friction lining so that the grooves or grooves pushed together during the shaping of the ring body that can be done without being hindered by the strips. The strips are expediently higher than those in the friction lining embossed grooves or grooves. But it can also be beneficial be to choose the slats a little lower and thus between a calibration or recompression of the To achieve friction lining.

Further details and advantages of the invention can be found in the following description of exemplary embodiments which are illustrated in the drawings. In the sen Figs. 1 and 2 show a flat annular body in the axia len central section and in plan view Fig. 3 and 4 to the reshaped to the friction ring annular body of FIGS. 1 and 2, likewise in the axial center section and in plan view. FIGS. 5 and 6 show another embodiment of a flat ring body, Fig. 7 and 8 to the friction ring formed from this annular body, Figs. 9 and 10 wei tere variant of the flat annular body, and FIGS. 11 and 12, the resulting friction ring produced by forming, in each case in the axial central section and in plan view. FIG. 13 shows a friction ring produced according to another method in the axial central section, and in FIG. 14 a top view of this. FIG. 15 shows a device for producing friction rings in the axial central section, and FIGS. 16 and 17 show details of a forming tool.

The friction rings shown in the drawings consist of an annular body 1 made of metal, which has friction surfaces 2 on two sides, each of which is provided with a sintered friction lining 3 . In Figs. 1 and 2, the ring body 1 is a plane, flat ring with flat friction surfaces 2. To manufacture the friction linings, the sintered powder is sprinkled onto the flat friction surfaces 2 , then sintered, pressed and, if necessary, calibrated in a manner known per se, so that a Streusin ter friction lining 3 suitable for the respective application is obtained. This friction lining 3 can be provided on both sides of the ring body 1 , as shown in the exemplary embodiments, or there may also be a friction lining 3 on only one side if a friction ring with only one friction surface is required in the application in question. As soon as the scattered sintered friction linings 3 have been completed, the ring body 1 together with the friction linings 3 is embossed, deep drawn or the like. in a cylindrical or, as shown in Figs. 3 and 4, brought into a slightly conical shape. This reshaping of the ring body 1 is possible without the scattered sintered friction linings 3 being deformed, flaking off or being unevenly compressed in a disadvantageous manner.

FIGS. 5 and 6 show also an initially flat annular body 1 having flat friction surfaces 2 on which scatter-sintered friction linings 3 are provided. These friction linings 3 are waffle-shaped, as can be seen particularly clearly from FIG. 6. In addition, driver grooves 4 are provided and projecting driver cams 5 between them . The driver grooves 4 can be produced together with the flat ring body by 1 , for example punched, but they can also be subsequently punched out, cleared or milled. The driving grooves 4 can not only be provided on the outer circumference of the ring body 1 , as shown in the drawings, but they can also lie on the inner circumference. The waffle-shaped grooving is expediently produced when the scattered sintered friction lining is pressed, as is known per se.

FIGS. 7 and 8 show the gene 3 provided with sintered powder Reibbelä annular body 1 according to FIGS. 5 and 6 after its conversion into a slightly conical shape. The waffle-shaped grooving can be seen schematically in the sectional view according to FIG. 7 on the inside of the ring body 1 .

The initially flat ring body 1 according to FIGS . 9 and 10 is provided with scatter sintered friction linings 3 , in which Ra dial grooves 6 are recessed. FIGS. 11 and 12 show the formed in a slightly conical shape friction body. Driver grooves 4 and projecting driver cams 5 are also provided there.

Another embodiment of the friction ring according to the invention is shown in FIGS. 13 and 14. There, too, the friction ring consists of an annular body 1 , which is provided on both sides with friction surfaces 2 , on which Streusin ter friction linings 3 are attached. The ring body 1 is made there, however, from a metal strip which, after sintering on the friction linings 3 , forms a closed ring and is then welded together at the joints by means of a weld seam 7 . The Mitnehmernok ken 5 , which are bent in this embodiment in the radial direction Rich against the ring body 1 , are attached laterally by a weld 8 on the ring body 1 .

In Fig. 15, a device for forming the sintered ring body 1 is shown. The left half shows the device in the open position before the machining of the ring body 1 , whereas in the right half of FIG. 15 the device is shown closed after the ring body 1 has been reshaped. This device consists of a forming tool with a die 9 and a punch 10 which can be displaced in the axial direction against the die. The die 9 is provided at its upper edge with an annular step 11 , in which the ring body 1 is inserted with its outer circumference. Inside the Ma trize 9 has a conically shaped surface 12 . The punch 10 , on the other hand, has at its lower end a conical molding surface 13 that matches the molding surface 12 of the die 9 . When the punch 10 is shifted from the open position shown in the left half of FIG. 5 into the closed position shown in the right half, the annular body 1 becomes exposed to the shaping surface 13 of the punch 10 , which presses the annular body 1 against the shaping surface 12 the die 9 presses, conically shaped.

In order to prevent that during the forming of the annular body 1 mounted thereon porous scatter-sintered friction lining 3 compressed by piece or is damaged, is provided between the annular body 1 and the molding surface 13 of the punch 10 an interim rule layer of resilient material inserted. In exporting approximately example of FIG. 15, this intermediate layer is a foil 14, for example made of plastic. This can be fed as an endless belt to the forming tool via rollers, not shown, and can be wound up, for example with the aid of a reel controlled in the work cycle. If necessary, an intermediate layer made of resilient material such as plastic or rubber can also be inserted between the shaped surface 12 of the die 9 and the ring body 1 . An annular end stop 15 for the ring body 1 is also fastened in the die 9 by means of a screw 16 . From the right half of FIG. 15 it can be seen that the reshaped ring body 1 rests with its end face against the end stop 15 .

Fig. 16 shows a variant in which the order form stamp 10 in the area of the molding surface 13 with an insert 17 made of resilient material, for example made of plastic, is provided. This insert 17 takes over the task of the film 14 provided in FIG. 15, which can be omitted.

Another variant is shown in FIG. 17. The stamp 10 is provided there in the region of the molding surface 13 with protruding bump-like strips 18 which are distributed over the molding surface 13 . The so formed forming die 10 engages only in the area of the strips 18 , which may have a rounded profile, on the Streusin ter-friction lining 3 of the friction body 1 to be reshaped, thereby ensuring that the reshaping sintering friction lining 3 is in any event over the largest part cannot affect its surface. If the friction lining 3 is provided with radial grooves 6 , as shown in the exemplary embodiment according to FIGS. 9 to 12, the strips 18 can be arranged and dimensioned such that they engage in the radial grooves 6 when the annular body 1 is deformed.

Claims (13)

1. Friction ring for clutches or brakes, which consists of a ring body ( 1 ) made of metal with at least one cylindrical or conical friction surface ( 2 ) which has a scattered sintered friction lining ( 3 ), characterized in that the friction linings ( 3rd ) are sintered directly onto at least one cylindrical or conical friction surface ( 2 ) of the ring body ( 1 ), the initially flat friction surfaces ( 2 ) after application of the scatter sintered friction linings ( 3 ) by non-cutting shaping, for example stamping, deep drawing or the like ., The ring body ( 1 ) are brought into the cylindrical or ko African shape. 2. A method for producing a friction ring according to claim 1, characterized by the following method steps:

• - Manufacture of an annular body ( 1 ) made of metal, preferably by punching, which is seen on its top and / or on its underside with a flat friction surface ( 2 ),
• - Applying a scattered sintered friction lining ( 3 ) to the provided flat friction surfaces ( 2 ), including pre-compression and, if necessary, simultaneous pressing of a grooving,
• - Forming the sintered ring body ( 1 ) by embossing, deep drawing or the like. in a form in which the sintered friction surfaces ( 3 ) are cylindrical or conical, and
• - Calibration and final compression of the friction lining ( 3 ).

3. The method according to claim 2, characterized in that already during manufacture of the ring body ( 1 ) before applying the scattered sintered friction lining ( 3 ) on the outer edge or on the inner edge of the same cam ( 5 ) and grooves ( 4 ) are formed as a driver. 4. The method according to claim 2, characterized in that after reshaping the sintered ring body ( 1 ) are welded to the sem driver. 5. A method for producing a friction ring according to claim 1, characterized by the following process steps:

• Producing a flat steel plate provided on at least one side with a sintered friction lining,
• Cutting a strip with straight or curved side edges from the sintered plate,
• - Bending the strip into a cylindrical or coni closed ring body and
• - Welding the abutting joints of the ring body ( Fig. 13 and 14).

6. The method according to claim 5, characterized in that axially or transversely to the ring axis projecting driver ( 5 ) are welded to the finished ring body ( 1 ). 7. A device for reshaping the sintered ring body according to the method of claim 2, with a die ( 9 ) and an associated punch ( 10 ) having a forming tool, characterized in that between the ring body ( 1 ) and the on a friction lining ( 3 ) engaging mold surface ( 13 , 12 ) of the punch ( 10 ) and possibly also the die ( 9 ) an intermediate layer ( 14 , 17 ) made of resilient material such as rubber or plastic is provided. 8. The device according to claim 7, characterized in that the intermediate layer of resilient material consists of a film ( 14 ) which is inserted between the ring body ( 1 ) and the forming tool acting on it ( 9 , 10 ). 9. The device according to claim 8, characterized in that the film ( 14 ) is fed as an endless belt via rollers for the forming tool ( 9 , 10 ). 10. The device according to claim 7, characterized in that the intermediate layer as in the shaped surface ( 13 ) of the stamp ( 10 ) and / or the die provided insert ( 17 ) is formed. 11. A device for reshaping the sintered ring body according to the method of claim 2, with a die ( 9 ) and an associated stamp ( 10 ) having the forming tool, characterized in that the shaped surface ( 13 ) of the stamp ( 10 ) and / or the die is provided with protruding strips ( 18 ) which can have a rounded profile. 12. The apparatus according to claim 11, characterized in that in a friction lining with grooves ( 6 ) or grooves the vorra ing strips ( 18 ) are arranged so that they engage in the grooves ( 6 ) or grooves. 13. The apparatus according to claim 12, characterized in that the strips ( 18 ) are narrower than the grooves ( 6 ) or grooves.