DE102008023696A1 - A method for the production of hollow shaft main bodies as well as hollow shaft main body produced by the method - Google Patents

Abstract

The invention relates to a method for producing hollow shaft base bodies and hollow shaft base body produced according to said method. Said method consists of a first step in which a preform (1a) having a transition diameter and a bore (4a) is produced by shaping, and an additional step in which the preform is shaped incrementally to form a hollow shaft base body (1b).

Description

By the EP 1 745 870 A1 discloses a method for producing hollow shaft main bodies, this method being characterized in that in a first step, the outer surface of a cylindrical starting material is machined by forming to obtain at least a predetermined diameter transition in the longitudinal direction of a base body. During this first step, namely by means of a cross wedge rolling process, a hole should also be formed by means of one or two mandrels. Thereafter, in a further method step, namely by incremental forming, the outer and / or inner surface of the base body is produced.

apart that the simultaneous feasibility of cross wedge rolling and the introduction of at least one mandrel of at least one Side to create at least one hole seems doubtful, the process described there is associated with considerable disadvantages, In particular, expensive and development-consuming tools for Carrying out the cross wedge rolling and achievable Cycle times are high, d. H. they are only small quantities per time unit. The cited in the EP OS Resource conservation argument may be used as an alternative Possibility of producing the bore by extrusion still apply (during extrusion only falls a relatively small slug as waste). However, this is cross wedge rolling even with regard to a resource conservation not optimal, because as is known, must be at the end of each cross wedge rolling process the two shaft ends of the cross rolling over the active Tool length pushed out material content are then sheared off and then is considered waste in front. The resource situation is worsened over it in addition, if - as further possible solution quoted - the Drilling produced before or after the cross wedge rolling process (although it remains unclear whether this process is a further step is to be evaluated).

Of the The present invention was based on the object, these cited Eliminate disadvantages and a simpler and cheaper production and to conserve resources further optimize. In addition, expensive developments of Tools should be avoided, continue to increase productivity be significantly improved and beyond, for the processing steps to be carried out subsequently Preform with optimum quality available too put. In addition, the production of the hole should be made so that for most applications, a post-processing of the same is no longer necessary, as described below Manufacturing method of the invention can thus produce bores be that a subsequent alignment of the hole is no longer necessary because of a thorn.

• – in einem ersten Schritt, in welchem sowohl die äußere Oberfläche eines zylindrischen Ausgangsmaterials als auch die Bohrung durch Umformen zu einem Vorformling bzw. einem Rohling bearbeitet wird, wenigstens ein vorbestimmter Durchmesserübergang in Längsrichtung des Vorformlings erzeugt wird, und
• – in einem weiteren Schritt der Vorformling durch Umformen der äußeren und/oder inneren Oberfläche des Grundkörpers inkrementell zu dem Hohlwellen-Grundkörper umgeformt wird.

The method for producing hollow shaft main bodies according to the invention provided with at least one bore is now characterized in that

• - In a first step, in which both the outer surface of a cylindrical starting material and the bore is machined by forming into a preform or a blank, at least a predetermined diameter transition in the longitudinal direction of the preform is generated, and
• - In a further step, the preform is formed by reshaping the outer and / or inner surface of the body incrementally to the hollow shaft body.

By the production of a preform or a blank by forming, this being the case for the vast majority of applications a forging process is particularly suitable, the blanks manufactured in simple tools and also provided with a bore and then serve as a raw material for the another step. The bore can either only partially be introduced into the body or continuously be. Even with continuous drilling is only a small Waste by expediently for the forging process associated punching of Butzens available. By the use of forging tools is a particularly favorable Mass production possible. The previously mentioned However, punching the Butzens can also in a separate operation done in a tool outside a forging tool. However, forming into a preform can also take place in a forming process take place, the half-warm or - z. B. depending on the required Forming degree or application - also performed cold becomes.

As a further step, in which the preform thus produced is further formed, namely, the inner and / or outer surface is formed, is in a particularly favorable manner, the so-called rotary swaging, which may be application or product-related cold or Halbwarmrundkneten. As a result, a near-net shape geometry can be produced in a particularly cost-effective manner and with maximum material utilization. Furthermore, this results in an optimal and uncut fiber profile, whereby the load capacity is favorably influenced. During this second step, the bore of at least one of the hollow shaft ends through the incremental procedures are closed.

The The invention further relates to hollow shafts, z. B. gear shafts, at least by the combination according to the invention one of the recited in the claims and protectable process steps are produced, the shaft being one continuous or one only partial introduced bore.

Farther It may be beneficial if during the first step to produce the preform this is provided with an undercut. This can be done, for example, by the fact that during the forging process at one of the forging stages a pusher tool is used, which consists of several on the forged body zubewegbaren segments exists, which moved together during the pressing process and are moved apart again to eject the part.

Based on 1 - 3 let the invention be explained in more detail.

The upper halves of the 1 - 3 in each case the preform and the lower halves, the hollow shaft contours produced therefrom.

In 1 indicates the preform 1a a shaft portion 2a and a flange portion 3a on and a through hole 4a , The shaft region as well as the bore may be cylindrical or conical.

The preform 1a is made by a forging process, which is performed in a multi-stage tool. One of the consequences is the bore 4a up to a slug 5 brought in. This slug is either punched out in a next station or can be punched out in a tool outside the forging tool.

In a second step, the preform becomes 1a to the hollow shaft body 1b reworked and in incremental as in particular by rotary swaging, while the flange area 3a are largely preserved and the incremental deformation in itself to the area 3b subsequent area be performed. Depending on the desired inner contour 4b , can by appropriate preforming the area 2 B and 2 B' in sections, a cylindrical or profiled mandrel of the flange 3a be turned away side.

The area 2 B' can be downsized in the end by incremental forming so that the bore 4b is closed at its end.

2 shows a further embodiment according to the invention, wherein the upper portion 11a of the 2 represents the preform and the lower portion in turn, the hollow shaft body 11b , Here, the bore introduced in the forging process is sufficient 12a only partially through the blank 11a in, the area generated by incremental forming is with 13 designated.

In 3 is the preform made by forging 21a with an undercut 22 provided, as well as the blank 21a , made by forging.

The at the bottom of the 3 illustrated hollow shaft body 21b is in the area 23 formed by rotary swaging. The area 23 can be supported by a mandrel depending on the desired inner shape during the forming process.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• EP 1745870 A1 [0001]

Claims (12)

Method of making with a bore provided hollow shaft bodies, comprising: - one first step, in which both the outer surface a cylindrical starting material by forming into a preform is processed, wherein at least a predetermined diameter transition in the longitudinal direction of the preform and at least one Partially extending bore is generated, and - one Another step in which the preform by forming the outer and / or inner surface of the body incrementally is converted to the hollow shaft main body. Method in particular according to claim 1, characterized in that that the second step is a rotary swaging. Method, in particular according to claim 1 or 2, characterized characterized in that the preform during the first Step is provided with an undercut. Method, in particular according to one of the claims 1-3, characterized in that the forming into a Preform done in a half-warm state. Method, in particular according to one of the claims 1-4, characterized in that the forming into a Preform is done in cold condition. Method, in particular according to one of the preceding Claims, characterized in that the incremental Forming takes place in a half-warm state. Method, in particular according to one of the preceding Claims, characterized in that the reshaping in another step is cold. Method, in particular according to one of the preceding Claims, characterized in that at least one the hollow shaft ends of the preform by incremental forming is closed again. Hollow shaft, characterized in that with their a bored base body: - in a first step, in which both the outer Surface of a cylindrical starting material as well the hole is machined into a preform by forming, wherein at least one certain diameter transition in Is produced longitudinally of the preform, and - of the Hohlwellengrundkörper in a further step, in which the preform by forming the outer and / or Incremental inner surface of the body is formed to the hollow shaft body. Hollow shaft, in particular according to claim 9, characterized characterized in that the bore is continuous. Hollow shaft, in particular according to claim 9, characterized characterized in that the bore is only partially through the shaft passes through. Hollow shaft, in particular according to one of the preceding Claims, characterized in that at least one the hollow shaft ends of the preform by incremental forming is closed.