DE202008017445U1 - expansion chucking - Google Patents

Abstract

Dehnspanneinrichtung, which consists of a base body and a thin-walled expansion sleeve made of steel, which is connected to form a closed, annular pressure chamber by means of a solder at least at its axial end portions with the base body, wherein the pressure chamber can be acted upon by elastic deformation of the expansion sleeve with a pressure medium, in order to realize a clamping action for a tool to be picked up, characterized in that the base body (2) and the expansion bushing (3) consist of steels with different carbon and / or chromium content, so that in the connection of base body (2) and expansion bush ( 3) by soldering a high-strength joint assembly by formation of elongated crystallites (9) as a result of Auflegierens the steel (10) with the lower carbon and / or chromium content arises.

Description

The The invention relates to a Dehnspanneinrichtung, which consists of a base body and a thin-walled expansion sleeve made of steel, the formation of a closed, annular pressure chamber by means of a solder at least at their axial end portions the main body is connected, wherein the pressure chamber below elastic deformation of the expansion sleeve with a pressure medium acted upon to a clamping action for a male Implement tool or workpiece. Dependent on of whether the expansion box by its elastic deformation the diameter of a hole is reduced or the diameter of a enlarged cylindrical receptacle, which is in a work spindle of a machine tool or with an interface provided Dehnspanneinrichtung in the position in turn z. B. cutting Shaft tools by internal tension (drill, end mill) or external tension (side milling cutter, workpiece bore) to record in a fixed manner. Such expansion chucks will then referred to as Dehnspannfutter or Dehnspanndorne.

Dehnspanneinrichtungen are well known in various embodiments and are used for high-precision clamping of components, in particular tool shanks or tool inner receptacles. For clamping, the expansion bush, which is located on the base body radially inward (expansion chuck) or outside (Dehnspanndorn) deformed and thus the tension of cylindrical or equipped with a bore components completed ( DE 100 07 074 A1 ). These components can be both tools and workpieces to be machined. In this case, the Dehnspanneinrichtung can be formed directly on the work spindle or machine side with a correspondingly formed machine interface, with which it is connected to the work spindle, are equipped.

at the known Dehnspanneinrichtungen are the main body and the expansion sleeve made of the same steel material, in particular in terms of carbon and / or chromium content, consisting and at their axial end portions by high temperature soldering connected with each other. Here, the high-temperature soldering has under inert gas or in vacuum enforced and it becomes a relative achieved error-free solder joint. The strength of the connection is only about 25% of the strength of the base material, because the solder joint through separate areas of the connecting components of Dehnspanneinrichtung (body, Stretching sleeve) is characterized by the intermediate solder. Furthermore, makes in the axial extension a large Connection length of the soldering required, so at least meets the above strength requirements can be.

These Solder joint is caused by the high Pressures, alternating loads during operation and thermal stresses heavily stressed during the preparation of the compound can lead to breakage of the joint connection. The connection point between base body and expansion sleeve thus provides a major weakness of the Dehnspanneinrichtung The strength of these determines decisively the Druckbeaufschlagbarkeit the expansion sleeve and thus limited for the Clamping relevant transmittable torque between Dehnspanneinrichtung and to the component to be clamped.

The Object of the present invention is a Dehnspanneinrichtung to propose a high strength but elastic connection of Body and expansion sleeve secures.

According to the invention this task in a generic Dehnspanneinrichtung solved by the features of claim 1 protection.

The Advantages of the invention are that a Dehnspanneinrichtung provided with a solder joint becomes, by which over the elongated crystallites into each other "toothed" joint partner approximate the strength of the process-influenced base material, in particular with regard to static and dynamic strength and shear strength, is achieved. In the axial direction becomes a high elasticity retained the solder joint.

in the Result can be provided a Dehnspanneinrichtung be with the larger torques on the too exciting components are transferable. It continues possible by reducing the soldering length at the tool end of the Dehnspanneinrichtung, a clear To achieve stiffer arrangement of the exciting part.

advantageous Further developments of the invention are in the protection claims 2 and 3 characterized.

The Invention is intended below to an embodiment and associated drawings explained in more detail become.

It demonstrate:

1 a sectional side view of a Dehnspanneinrichtung invention in the form of a Dehnspannfutter in a first embodiment

2 a sectional side view of a Dehnspanneinrichtung invention in the form of a Dehnspannfutters in another embodiment

3 a solder joint on the Dehnspanneinrichtung invention with elongated crystallites formed in the magnification 200: 1

In the 1 and 2 is an example as expansion chuck ( DIN 69893-1 part 7 ) shown Dehnspanneinrichtung 1 shown. This consists of a basic body 2 and a thin-walled expansion sleeve 3 , which in one at the basic body 2 provided receiving bore 4 is used and to form a closed, annular pressure chamber 5 by means of a solder 6 at least at their axial end portions 7 with the main body 2 connected is. Here is the pressure chamber 5 by means of a pressure element via feed channels for elastic deformation of the expansion sleeve 3 with a print medium 8th , Hydraulic oil, preferably acted upon to realize a clamping action for a male tool or workpiece (not shown). If the pressure is correspondingly reduced, the expansion sleeve will spring back 3 back to their original position and the object can be removed.

The design of the solder joint can be different forms, such as, inter alia, in 2 shown, have. Alternatively, not shown further connection points between base body 2 and expansion sleeve 3 be equipped with the soldering.

Due to the fact that the joining partners, the basic body 2 and the expansion box 3 , made of steels 10 . 11 With different carbon and / or chromium content, separate Fe-C cluster and / or Fe-Cr cluster from the carbon and / or chromium-rich joining partners in high-temperature soldering, there is a crystal formation in the result elongated crystallites 9 , in particular columnar crystallites, grow over the soldering seam to the lower-alloyed joining partner, which is alloyed accordingly. Differences in the C content of 0.2 to 2.5% and / or in the Cr content of 4 to 28% are particularly advantageous between the joining partners. The endeavor of the differently alloyed steels is used to achieve an alloy equilibrium state. The lot 6 serves as a connection medium between the base body 2 and expansion sleeve 3 , The result is a high-strength solder joint with each other "toothed" joining partners, which achieved in addition to a high elasticity in the axial direction approximately the strength (significantly higher static and dynamic strength, Torsionsbelastbarkeit, shear strength and fatigue strength) of the process-influenced base material.

By such a connection, it is possible, the pressurization of the expansion sleeve 3 to increase significantly higher torque transfers from the Dehnspanneinrichtung 1 to reach the exciting part. Furthermore, the previously required large connection length of the soldering can be significantly reduced. Thus, especially at the tool end of the expansion sleeve 3 achieved a much stiffer arrangement. Using the carbon and / or chromium steel 10 for the main body 2 and the carbon and / or chromium richer steel 11 for the expansion sleeve 3 , So obtained after tempering a composite material of a "soft" body 2 To protect the machine interface with a hard, wear-resistant expansion sleeve 3 allows for component picking. According to the invention, the same high-strength, elastic solder joint is formed even when choosing the high-alloy steel 11 for the main body 3 and lower alloy steel 10 for the expansion sleeve 2 , This may be either alone the C content, the Cr content or both components in combination.

For producing a Dehnspanneinrichtung 1 it is intended, an expansion sleeve 3 , preferably from 1.2379 (X155CrVMo 12-1) with a C content of 1.55% and a Cr content of 12%, in a receiving bore 4 a lower alloyed body 2 , preferably from 1.2343 (X38CrMoV 5-1) with a C content of 0.38% and a Cr content of 5%, to be soldered to high strength with pure Cu solder. Thus, it is the body 2 around a steel 10 with lower carbon and chromium content while the expansion sleeve 3 from a steel 11 exists, which has a higher carbon and chromium content compared to the base body. The soldering gap width is in a range of 10 to 50 microns. The expansion sleeve 3 and basic body 2 are vacuum-brazed in a temperature range of 900 ° C to 1200 ° C and with a holding time of 5 to 30 min. This creates a high-strength solder joint, as in the 3 is shown in an enlargement. This compound points through the strength-enhancing elongated crystallites 9 Strength values similar to the material of the main body 2 on. The inventive design of the soldering creates a structure according to the 3 , where the soldering 4 is formed such that by the parameters according to the invention a tooth-like soldering structure with it by elongated crystallites 9 building connecting soldering partners.

1

expansion chucking

2

body

3

expansion sleeve

4

location hole

5

pressure chamber

6

solder

7

end

8th

print media

9

elongated crystallites

10

carbon- and / or less chromium steel

11

carbon- and / or chromium richer steel

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

• - DE 10007074 A1 [0002]

Cited non-patent literature

• - DIN 69893-1 part 7 [0015]

Claims (3)

Dehnspanneinrichtung, which consists of a base body and a thin-walled expansion sleeve made of steel, which is connected to form a closed, annular pressure chamber by means of a solder at least at its axial end portions with the base body, wherein the pressure chamber can be acted upon by elastic deformation of the expansion sleeve with a pressure medium, to realize a clamping action for a male tool, characterized in that the basic body ( 2 ) and the expansion sleeve ( 3 ) consist of steels with different carbon and / or chromium content, so that in the connection of main body ( 2 ) and expansion bushing ( 3 ) by soldering a high-strength joint assembly by formation of elongated crystallites ( 9 ) due to alloying of the steel ( 10 ) is formed with the lower carbon and / or chromium content. Dehnspanneinrichtung according to claim 1, characterized in that the basic body ( 2 ) the steel ( 10 ) with the lower and the expansion sleeve ( 3 ) the steel ( 11 ) with the higher carbon and / or chromium content. Dehnspanneinrichtung according to claim 1, characterized in that the expansion sleeve ( 3 ) the steel ( 10 ) with the lower and the base body ( 2 ) the steel ( 11 ) with the higher carbon and / or chromium content.