DE10121546A1 - Process involving pressure roller to deform hub has offset of greater diameter than hub formed in transition region of radial region of workpiece and hub - Google Patents

Abstract

The hub deforming process involves rotating a workpiece (14) in a pressure roll machine with a shaped roller (22) to reduce a radial region of the workpiece, shifting material along a forging region (30) to form the hub (34). An offset (36) of greater diameter than the hub is formed in the transition region between the radial region of the workpiece and the hub.

Description

The invention relates to a method for molding a Hub according to the preamble of claim 1. Further relates the invention of a spinning roller for molding a hub after the preamble of claim 9.

A method and a spinning roller of the aforementioned Kind are known from DE 198 49 981 C2. With this known methods can be particularly economical Way gear parts are manufactured with hub, which serve in particular for torque transmission. Procedure A transition area between the hub and a radial workpiece area during manufacture claimed. This can increase the strength of the finished Ge affect the drive part.

The invention has for its object a method and specify a spinning roller with which gear parts with high strength hub on simple and reliable Can be produced in this way.

The invention solves the problem by a method with the Features according to claim 1, a method with the features according to claim 7 and by a spinning roller with the Merkma len according to claim 9.

Advantageous developments of the invention result from the dependent claims.  

In the inventive method according to claim 1 provided that in a transition region of the radial loading rich of the workpiece and the hub formed a paragraph and that the shoulder is larger than the hub diameter is.

A basic idea of the invention is that when Forming the heel is an axial flow of material when forming the hub is specifically inhibited in the transition area.

Subsequent material is also opposed to that te, to the side of the hub facing away from the hub to be molded Workpiece pressed. The formation of a constriction tion on the back of the workpiece completely or closed at least largely avoided. At the same time, the structure of the material due to the lower degree of deformation that by first shaping the diameter larger sales is caused, less stressed, so that the formability of the structure is less exhausted and the risk of embrittlement is prevented.

To transfer relatively high speed with the hub Allowing moments is a preferred variant of the procedure proposed to reformulate the paragraph in such a way that its wall thickness is at least partially larger than the wall thickness of the hub. The transition of the workpiece to the hub is additionally due to a material accumulation reinforced. For this purpose, the spinning roller at the Ausfor the hub so that the paragraph with its Internal dimensions at least approximately the internal dimensions the hub is shaped accordingly.

Alternatively, material and weight can be saved can be achieved according to the fact that in the area of Ab  a free space lying on the inner circumference of the hub is formed. This can be done by delivering the Spinning roller or by an appropriate form of pressing dornes can be reached.

At least in sections towards the Na Form the tapered paragraph, the role can be such that the line of contact with which the section of the compression area which forms the heel Workpiece touches, at least during the molding of the Ab set inclined with respect to the axis of rotation of the workpiece runs.

So that the outer contour of the hub on the finished workpiece at least approximately parallel to the symmetry axis of the work piece runs, the role is preferred zugewseise represents the line of contact with which the hub touches forming section of the upsetting area the workpiece stirs in parallel, at least while the hub is being formed runs to the axis of rotation of the workpiece.

Furthermore, it is advantageous to use the axial material flow along the compression area through a compression area final radial projection on the lateral surface of the Limit role so that the outer contour of the hub through the outer contour of the roll is specified.

When using a counter holder with which the Workpiece secured to the workpiece holder for rotation alternatively, it is also possible to use one on the counter holder provide appropriate projection with which the axial Ma material flow along the upsetting area is limited.  

In a particularly preferred method variant proposed a workpiece holder at the spinning mill machine to use, on the workpiece contact surface annular recess is provided. By using egg With a workpiece holder designed in this way, it is possible when delivering the roll of material to the back of the Workpiece with which the workpiece is at least partially the workpiece contact surface rests against the workpiece Form the contact surface trained recess. Hereby is a targeted material thickening and reinforcement reached the back of the workpiece.

The role can be adjusted when molding the hub that the hub is in the area of the workpiece holder formed annular recess is formed. Here through it comes especially in the Gebil the transition area of the workpiece to the hub to a dimension material accumulation, through which the formation of constrictions at the back of the workpiece with high reliability can be prevented.

According to a further method of the invention according to claim 7 it is proposed that the circular workpiece in front of the Forming and / or while the hub is being formed onto a Temperature above the recrystallization temperature of the Workpiece material to be heated and preferably also maintain this temperature. By warming the plant piece to a temperature above the recrystallization temperature is reached that the structure changes during the Reshaping the hub can form. This will make the the forming process hinders tensions in the structure mined continuously so that the material is a clear shows higher formability and the structure is particularly nice can be reshaped. In this way, in particular embrittlement of the material due to a too high  Degree of deformation prevented, so with this method esp special workpieces made from high-strength steels which, due to their material properties, can be used for high torque at low weight are suitable. This procedure can also be used in combination the previously mentioned procedural alternatives be set.

The workpiece temperature can preferably be set in this way be that after a defined partial forming un ter the recrystallization temperature drops. When through Management of the remaining forming can then be work hardened again occur so that a defined strength state occurs is adjustable.

The invention further relates to a spinning roller, as in Claim 9 is defined, in particular for implementation of the method according to claim 1 can be used. At the compression area of the press roller according to the invention instructs its entrance area a gradation through which when the hub is formed in a transition area between the radial area of the workpiece and the hub a heel larger than the hub can be formed is. The inventive design of the spinning roller is achieved that the displaced by the spinning roller Material of the workpiece when molding the hub in on stagnation area and flowing material in to some extent is pushed in the opposite direction. The advantages of the method described above are thus attainable.

In a preferred embodiment of the invention The roller forming the entry area is closed by the spinning roller section of the role and the following de, the section of the roll forming the compression area  an obtuse angle. In this way it is achieved that the material flowing into the entrance area is gentle, d. H. with only a comparatively small change in direction tion into the compression area.

The entry area is in a preferred embodiment shape of the roll by a cylindrical jacket section formed, which in at least some sections The conical shell section of the compression area forming the Role passes. This roll shape makes it possible to Roll with its axis of rotation inclined to the axis of rotation to deliver the workpiece so that the material of the factory only slightly through the entrance area is deformed, while higher forming forces only in the upset attack the area of the material, i.e. at a distance from the radia len area of the workpiece occur, which in particular the transition area between the workpiece and the hub is special is gently formed.

Basically, a blunt pressure roller can be used the. So that the material of the workpiece is as uniform as possible but it is deformed gently and gently by the roller of advantage if a separating edge is formed on the roller that goes into the entrance area. The the parting edge-forming lateral surfaces of the roll prefer close have an acute angle, which makes the separating edge a Has wedge shape. In particular, due to the wedge shape, it becomes is enough that the spinning roller with a comparatively low Zu force can penetrate into the material of the workpiece.

Furthermore, it is proposed to roll the compression area to limit le by a circumferential radial projection, around the axial material flow in the upsetting area during molding to stop the hub.

In the following, the invention is based on several examples drafted variants of the process and the pressure roller: under Further explained with reference to the drawing. Show in it in a sectional view:

Figure 1 is a schematic side view of a press roll machine when molding a hub after egg ner first variant of a method according to the invention using a press roller according to the Invention.

Fig. 2 is a schematic side view of a pressure rolling machine when molding a hub according to a second variant of a method according to the invention;

Fig. 3a-e sectional views of a workpiece, in which five different stages of the process of forming the hub are shown by the method shown in Fig. 2;

Fig. 4 is a schematic side view of a. Press-rolling machine at the beginning of the forming of a hub according to a third variant of a method according to the invention, an annular recess being provided on the workpiece holder of the press-rolling machine;

Fig. 5 is a schematic side view of the pressure rolling machine during the molding of the hub according to the third method variant;

Fig. 6 is a schematic side view of the press-rolling machine after the hub has been formed in accordance with the third method variant;

Fig. 7 is a schematic side view of a pressure rolling machine after forming a hub according to a fourth variant of a method according to the invention;

Fig. 8 are sectional views of a workpiece, in which the three different stages of the process of forming the hub are shown according to the fourth method variant shown in FIG. 7;

Fig. 9 is a schematic side view of a pressure rolling machine after forming a hub according to a fifth variant of a method according to the Invention.

Fig. 10 is a schematic side view of a pressure rolling machine when molding a hub according to a further method according to the invention; and

Fig. 11 is a schematic side view of a pressure rolling machine when molding a hub.

The invention is based on the knowledge that under certain circumstances, for example from a certain degree of solidification, a constriction effect can occur when molding a hub, which will be explained below with reference to FIG. 11.

In Fig. 11, a pressure rolling machine 210 is shown in a schematic side view, which forms a hub 214 on a circular workpiece 216 using a pressure roller 212 . The pressure roller 212 is fed radially for this purpose, so that a radial area of the workpiece 216 is reduced in its wall thickness. The material obtained flows along a compression area 218 formed on the pressure roller 212 and is thereby formed into the hub 214 .

When this pressure roller 212 is used, the end face 220 and the outer surface of the pressure roller 212 forming the compression region 218 form a separating edge. Due to the process, the material is exposed to high loads and forming forces.

This can lead to the formation of a constriction 222 on the rear side of the workpiece 216 facing away from the hub 214 . This means a material weakening, through which the strength of the finished transmission part is considerably reduced. In addition, microcracks can develop in this area. There is also a risk that the hub 214 will tear off during the molding.

In Fig. 1, a pressure rolling machine 10 is shown in side view in a schematic representation. The spinning roll machine 10 has a workpiece holder 12 on which a circular workpiece 14 is held. The disc-shaped work piece 14 has in its center a concentric opening 16 through which the tool mandrel 18 of a counter-holder 20 projects, with which the workpiece 14 is pressed against the workpiece holder 12 and is clamped in a rotationally fixed manner.

Furthermore, the spinning roll machine 10 has a spinning roller 22 which is rotatably mounted about a tool axis W and is radially and axially adjustable with respect to the axis of rotation R of the workpiece 14 . An end face 24 of the pressure roller 22 shown on the left in FIG. 1 merges into a separating edge 26 , the lateral surfaces of the pressure roller 22 forming the separating edge 26 enclosing an acute angle. To form a gradation 31 is a cylindrical inlet portion 29 and an obliquely extending paragraph upsetting region 28 adjoins the cutting edge 26, wherein the axis of rotation R may extend at an oblique angle of up to 90 ° the Ab set upsetting region 28 forming lateral surface with respect to. The heel compression region 28 in turn merges into a compression region 30 which is delimited in the axial direction by a radial projection 32 .

A first method variant of the invention is described below described method.

In order to form a hub 34 on the workpiece 14 , the pressure roller 22 is initially axially and at the same time radially so far in the direction of the workpiece holder 12 until the separating edge 26 partially penetrates into the radial region of the workpiece 14 rotating about the axis of rotation R. The pressure roller 22 is set with its tool axis W in such a way that the jacket surface adjoining the separating edge 26 and the jacket surface 30 forming the compression region 30 of the pressure roller 22 run at least approximately parallel to the rotation axis R of the workpiece 14 . The compression area 28 forming the lateral surface is inclined to the axis of rotation R is aligned, while the radial projection 32 extends at least approximately at right angles to the axis of rotation R.

Is entered after the severing edge 26 piece surface a predetermined amount in the factory, the pressing roller 22 is only radially infed in the direction of the rotation axis R, wherein the removed by the cutting edge 26 material passed from the separator edge 26 roll in the paragraph compression region 28 of the pusher 22 and from this is forwarded into the compression area 30 , in which the radial projection 32 limits the axial material flow.

Due to the inclined course of the heel upsetting area 28 with respect to the axis of rotation R of the workpiece 14 , a back pressure of the material flowing into the upsetting area 30 occurs at the heel upsetting area 28 , so that the material is also pressed in the direction of the rear side of the workpiece 12 facing away from the hub 34 is, so that, if at all, only a practically negligible constriction 35 forms. The feed movement of the pressure roller 22 is continued until the gap between the pressure roller 22 and the counter-holder 20 is completely filled with material. In this way, the hub 34 shown in FIG. 1 is formed, the outer contour of the hub 34 corresponding to the outer profile of the pressure roller 22 , while the inner contour of the hub 34 corresponds to the outer contour of the counter-holder 20 .

Since the material is first formed as a shoulder 36 , which starts from the radial region of the workpiece 14 into the Na 34 and is larger in diameter compared to the outer diameter of the hub 34 , high strength is achieved in the critical transition region to the hub 34 .

In the method described above, the heel compression region 28 is completely filled when the hub 34 is formed on the basis of the set forming parameters. The inner diameter of the shoulder 36 corresponds at least approximately to the inner diameter of the hub 34 , as a result of which the specially guided transition region from the workpiece 14 into the hub 34 is additionally reinforced by material accumulation.

In Fig. 2 is a side view of the press-rolling machine 10 shows ge, the workpiece 14 a in this case made of another material, for example a higher-strength steel. The forming parameters of the press-rolling machine 10 are set in this second method variant such that the shoulder 36 a formed after the molding of the hub 34 a has at least approximately the wall thickness of the hub 34 a, with a free space 37 remaining on the inner circumference. In this way, it is possible to manufacture a workpiece 14 a, which is compared to a product obtained by the described with reference to FIG. 1, process variant workpiece 14 has a lower weight.

The workpiece 14 a thus produced can then be further shaped, for example into a gear part. The individual process steps in the manufacture of one of the gear parts are shown in FIGS . 3a to 3e Darge. First, the hub 34 a with the shoulder 36 a is formed on the round-shaped workpiece 14 a (cf. FIGS . 3a and 3b). Subsequently, the workpiece 14 a is processed on the same or a further pressure rolling machine, the back of the workpiece 14 a being partially drawn in by pressure rolling (cf. FIG. 3 c). After pulling in, the outer edge is folded (cf. FIG. 3d) and rolled against a tool mandrel (not shown) by pressure rolling, through which elements, here a toothing Z, are formed on the inside of the folded outer edge.

FIGS. 4 to 6 show a flow-forming machine 10 b, the structure of which essentially corresponds to the above described the spinning rolling machine 10 corresponds. The essential difference to the pressure rolling machine 10 is a recess 13 b at the workpiece holder 12 b of the pressure rolling machine 10 b.

With this press rolling machine 10 b, it is possible to shape the workpiece 14 b according to a third variant of the method according to the invention. Rensvariante In this third procedural the pressing roller 22 b so notified that the material during the molding of the hub 34 b b in the recess 13 is at least partially formed, as Fig. 5 shows.

The deformation parameters may be provides in the process sequence is so that the rear of the workpiece shows a minimum at approximately schedule course, as FIG. 6, on or has usually the recess 13 b to form ei ner additional reinforcing material fully fills.

Fig. 7 shows a further modified embodiment of the flow-forming machine according to Fig. 1. The modified flow-forming machine 10 c is different from the flow-forming machine 10 in that c in the workpiece holder 12 a From recess 13 c is formed, the profile of the contour of the back of the Workpiece 14 c corresponds.

This press-rolling machine 10 c is operated with a fourth method variant, in which the forming parameters during the molding of the hub 34 c are set in such a way that the press roller 22 c partially forms the back of the workpiece 14 c into the recess 13 c from the workpiece holder 12 c while the hub 34 c is formed with paragraph 36 c. The additional reinforcement of the rear side of the workpiece 14 c ensures that the transition region between the radial region of the workpiece 14 c and the hub 34 c is correspondingly reinforced.

In FIGS. 8A to 8C, the process flow is shown in the manufacture of a gear part in which the previously described flow-forming machine 10 c is operated using the fourth process variant. First of all, a forged or cast preform of the workpiece 14 c is inserted into the press-rolling machine 10 c (cf. FIG. 8 a). The preform has a reinforced central area on the front according to the material required for the molding of the hub 34 c and on the back to sufficient Fe strength against constriction. Subsequently, the hub 34 c and the shoulder 36 c are formed in the manner described above, the back of the workpiece 14 c retaining its contour in the recess 13 c (see FIG. 8 b). At closing the outer edge of the workpiece 14 c is folded over and provided with splines Z on its outer surface by spinning (see. Fig. 8c).

FIG. 9 shows a further modified embodiment of the pressure rolling machine 10 shown in FIG. 1. In this water-rolling machine 10 d, a pressure roller 22 d is used, which has a separating edge 26 d, which merges directly into a compression area 30 d. In this method according to the invention, the pressure roller 22 d is set with its tool axis W with respect to the axis of rotation R of the workpiece 14 d in such a way that the outer surface forming the compression region 30 d extends at a predetermined angle to the axis of rotation R of the workpiece 14 d, so that a Free space 37 d is formed.

Before the hub 34 d is formed, the workpiece 14 d is first heated to a temperature which is above the recrystallization temperature of the material of the workpiece 14 d. Subsequently, the workpiece 14 d heated in this way is inserted into the press-rolling machine 10 d, the counter-holder 20 d coming into contact with the front of the workpiece 14 d. Then the pressure roller 22 d is delivered and the hub 34 d is formed, the temperature of the workpiece 14 d being kept above the recrystallization temperature during the molding of the hub 34 d by suitable heating devices (not shown).

By heating the workpiece 14 d to a temperature above the recrystallization temperature it is achieved that the structure continuously forms during the molding of the hub 34 d. In this way, obstructions in the structure are reduced, so that the material shows a significantly higher formability and the structure can be formed particularly gently. In addition, embrittlement of the material due to an excessive degree of deformation is prevented in this way, so that in particular workpieces made of high-strength steels can be processed with this method, which due to their material properties are suitable for transmitting high torques with a low weight. The gentle material handling also largely avoids material constrictions.

Referring to FIG. 10, a further variant is illustrated for performing the method described above. For this purpose, a spinning roller 112 , a spinning roller machine 110 is used for shaping the workpiece 116 . In contrast to the above, the separating edge is rectangular, the end face 120 being inclined to the axially extending compression region 118 by the angle cz, which is only a few degrees. In the parallel arrangement of the spinning roller axis W to the axis of rotation R, a reliable material removal with simultaneous good support of the workpiece 116 by the spinning roller 112 is sufficient.

The previously described method variants represent only a few of the possible embodiments of the method according to the invention. For example, the workpiece can also be heated to a temperature above the recirculation temperature in the method variants described with reference to FIGS. 1 to 8, the temperature also possibly can be kept above the recrystallization temperature during the molding of the hub. Furthermore, it is also possible to form two hubs or cylindrical projections on the workpiece.

Claims (13)

1. A method of molding a hub in which
a circular workpiece ( 14 ) is set in rotation on a pressure rolling machine ( 10 ),
at least one pressure roller ( 22 ) is delivered which has a compression area ( 30 ) with an outer profile which corresponds at least in sections to the outer contour of the hub ( 34 ) to be molded on the workpiece ( 14 ), and
upon delivery of the pressure roller ( 22 ), a radial loading area of the workpiece ( 14 ) is reduced in its wall thickness and the material obtained is formed along the compression region ( 30 ) of the pressure roller ( 22 ) to form the hub ( 34 ),
characterized by
that a shoulder ( 36 ) is formed in a transition region of the radial region of the workpiece ( 14 ) and the hub ( 34 ) and
that the shoulder ( 36 ) compared to the hub ( 34 ) is larger by knife. 2. The method according to claim 1, characterized in that the shoulder ( 36 ) in its inner dimensions is at least approximately shaped according to the inner dimensions of the hub ( 34 ). 3. The method according to claim 1, characterized in that in the region of the shoulder ( 36 ) on the inner circumference of the hub ( 34 ) lying free space ( 37 ) is formed. 4. The method according to any one of the preceding claims, characterized in that the axial material flow along the upsetting area ( 30 ) is limited by a upsetting region ( 30 ) from closing radial projection ( 32 ) on the surface of the roller ( 22 ). 5. The method according to any one of the preceding claims, characterized in that material on the back of the workpiece ( 14 ) with which the workpiece ( 14 ) at least partially abuts a workpiece contact surface of a workpiece holder ( 12 ) of the spinning roll machine ( 10 ) the workpiece contact surface formed annular recess ( 13 ) is formed. 6. The method according to claim 5, characterized in that the hub ( 34 ) opposite to the annular recess ( 13 ) is formed. 7. The method according to the preamble of claim 1, characterized in that the circular-shaped workpiece ( 14 ), which in particular consists of a high-strength material in particular, before molding and / or during molding of the hub ( 34 ) to a temperature above the recrystallization tion temperature of the workpiece material is heated and preferably held on this. 8. The method according to any one of the preceding claims, characterized in that the edge of the workpiece ( 14 ) is further deformed, in particular thickened, pressure-rolled, profiled and / or toothed. 9. pressure roller for molding a hub, in particular according to one of claims 1 to 8,
with a compression area ( 30 ) which has an outer profile which corresponds to an outer contour of a hub ( 34 ) to be molded on a radial area of the workpiece ( 14 ),
characterized,
that the compression area ( 30 ) has a step ( 31 ) at its entry area ( 29 ), through which, when the hub ( 34 ) is formed in a transition area between the radial area of the workpiece ( 14 ) and the hub ( 34 ), one opposite the other Hub ( 34 ) diameter larger paragraph ( 36 ) can be formed. 10. spinning roller according to claim 9, characterized in that an adjoining the entry region ( 29 ) ß sales compression area ( 28 ) with the adjoining compression area ( 30 ) includes a blunt angle. 11. spinning roller according to claim 9 or 10, characterized in that the gradation ( 31 ) comprises a cylindrical entry area ( 29 ) which is adjacent to a conical heel compression area ( 28 ). 12. spinning roller according to one of claims 9 to 11, characterized in
that a separating edge ( 26 ) is formed at a free end of the entry region ( 29 ) and
that the lateral surfaces forming the separating edge ( 26 ) form an angle between 10 ° and 90 ° and preferably form a sharp-edged separating edge ( 26 ). 13. spinning roller according to one of claims 9 to 12, characterized in that the compression region ( 30 ) is delimited by a circumferential radial projection ( 32 ).