DE20204381U1 - Machining tool, in particular rotating milling tool - Google Patents

Description

Tool for machining, especially rotating milling tool

The invention relates to a tool for machining, in particular a rotating milling tool according to claim 1.

From DE 297 05 575 a tool has become known which has a shaft which can be clamped into a machine tool or a machine spindle and whose end is provided with a tool head. A tenon is formed onto the shaft and the tool head has a bore as a tenon holder, whereby the tenon can be secured in the tenon holder by means of a shrinking process in a force-locking manner. The tool holder or the tool chuck is enlarged in diameter when the temperature increases. After cooling, a cylindrical tenon which is inserted in the expanded, tumbled state is preformed.

...12

German Patent Attorneys, European Patent and Community Trade Mark Attorneys

Authorised representative of the European Economic Area, Partnership and Harmonisation Office for the Internal Market

Deutsche Bank AJJ HJnJbUVg, No. OS 2*97i(BLZ*20(I7O0 ?4X-.Postbar;k jlarjiburg, No. fc 4l 2(35 (BLZ 200 100 20)

*·· "'DresdfteVBairfcAOtiambur^No. 233 6C3$'(BLZ*20Qf!.00 &Ogr;&Ogr;^&iacgr; !

-�Igr;ναγ the recess is subjected to radial clamping pressure. As long as the deformation is within the elastic range of the material used, the clamping is reversible and repeatable. It is also known to manufacture the tool shank, including the pin, from hard metal. This has the advantage that the shank breaks if the lateral stress is too great.

The removable shrink connection between the tool head and a holder has the advantage that it can be made or released within a very short time. In addition, a high level of processing reliability is achieved.

With a pure shrink connection, the power transmission is achieved solely by force-locking. To increase the bending stiffness, it is therefore important that the flat contact surfaces of the tool head and tool holder lie against each other; this also has a positive effect on the vibration behavior in the milling process. Shrink-fit tool connections have the advantage of high concentricity and are therefore particularly suitable for use in the HSC area, i.e. high-speed machining.

EP 1 106 288 A1 discloses a chuck for clamping tools in a shrink fit, in which the chuck body has a central receptacle that is open at one end for inserting and receiving the tool to be clamped with its shank. The chuck body has a central receptacle at the open end of the receptacle.

-3-

holder has a front-side contact surface for the tool to be inserted, which can abut axially on the contact surface with a rear shoulder when inserted. In the area of an end section of the chuck body that carries the contact surface, a ring element is arranged that is axially supported on the chuck body in an axial direction and has a stop surface assigned to the shoulder of the tool at the front on the front end axially adjacent to the contact surface for axially bracing an inserted tool by means of the ring element in relation to the chuck body. When the holder and ring element heat up, the latter is stretched more. After the tool shank has been fitted into the holder and cooled, the conical ring element on the conical outer surface of the holder moves towards the contact surface of the tool in order to achieve the flat contact.

The invention is based on the object of creating a tool for machining, in particular a rotating milling tool, in which a force-fitting contact between the surfaces of the tool head on the one hand and the tool holder on the other hand is reliably achieved.

This object is solved by the features of claim 1.

In the tool according to the invention, two joining rings are arranged next to each other between the contact surfaces. The joining rings have flat circular ring surfaces on the outside, which extend perpendicular to the axis of the rings. The mutually

SJ-j

facing surfaces of the joining rings are provided with ramp surfaces running in opposite directions such that when the rings rotate relative to one another, they are moved axially apart in the direction of the flat contact surfaces of the tool and tool holder. According to one embodiment of the invention, the ramp surfaces are formed by helical surfaces. The ramp surfaces of the joining rings can be shaped such that the joining rings engage one another in a form-fitting manner.

Before the preferred shrink connection is made, the joining rings are pushed onto the pin to be shrunk so that they are located between the contact surfaces of the tool and the tool holder. After the shrink connection has been made, the rings are rotated relative to each other so that they are pressed apart into a tight fit against the associated contact surfaces of the tool and the tool holder. In this way, a secure frictional connection between the tool and the tool holder is also achieved in this area. As an alternative to the shrink connection, a hydraulically or otherwise operated tool holder can also be provided.

In order to achieve a simple relative rotation of the rings against each other, according to one embodiment of the invention, recesses or the like are formed on the outer circumference for engagement with a corresponding tool.

The invention is explained in more detail below using an embodiment.

Fig. 1 shows the side view of a milling tool and a tool holder for a shrink connection with joining rings.

Figs. 2 and 3 show an enlarged side view of the joining rings according to Fig. 1.

Fig. 1 shows a tool head 10 to which indexable inserts 12 can be attached. This is a copy milling cutter. However, this is of no importance for the invention to be described below.

On the end opposite the tool side, the tool head 10 has a pin 14 (shown in dashed lines). The pin 14 can be formed as one piece with the tool head 10 or connected to the tool head 10 via a shrink connection or also via a screw connection. The latter connections are not shown in Fig. 1.

The pin 14 is seated in a receiving bore 16 of a partially shown tool holder 18. The tool holder 18 is conventional and will not be explained further.

When the tool holder 18 is cold, the diameter of the receiving bore 16 is minimally smaller than the outer diameter of the pin 14. The dimension

The solution is such that when the tool holder 18 is heated accordingly, the pin can be inserted into the bore 16 so that a shrink connection is produced after cooling.

An annular flat contact surface 22 is formed between the body 20 of the tool head 10 and the pin 14. The tool holder 18 also has a flat contact surface 24 at the open end of the holder bore 16. Two joining rings 26, 28 are arranged between the contact surfaces 22, 24. The joining rings 26, 28 are shown more clearly and enlarged in Figures 2 and 3.

It can be seen that the joining rings 26, 28 have flat ring surfaces 30, 32 on their respective outer sides, while they have helical surfaces 34, 36 on the sides facing each other. A step 38 or 40 is provided at the end. The joining rings 26, 28 engage with each other in a form-fitting manner via the helical ramp-like surfaces 34, 36. In the illustration according to Fig. 2, in which the steps 38, 40 lie against each other, both rings 26, 28 together have the smallest width. If the rings 26, 28 are rotated against each other, as shown in Fig. 3, the outer surfaces 30, 32 move axially apart.

If the shrink connection described in connection with Fig. 1 does not result in a force-fitting connection of the described parts, the relative rotation of the joining rings 26, 28 takes place as described so that the surfaces 30, 32 are in full force-fitting

-7-

sible system to the flat surfaces 22, 24. The necessary rotation of the joining rings 26, 28 is carried out with the aid of a tool which engages in corresponding recesses 42 and 44 of the joining rings.

Claims (5)

1. Tool for machining, in particular a rotating milling tool, with a tool head which has a machining end and, at the opposite end, a clamping section which can be clamped into a tool holder of a machine tool, the clamping section and the tool holder having flat contact surfaces, characterized in that two joining rings ( 26 , 28 ) are arranged next to one another between the contact surfaces ( 22 , 24 ), which have flat circular ring surfaces ( 30 , 32 ) on the outside, the plane of which runs perpendicular to the axis and the surfaces facing one another have ramp sections ( 34 , 36 ) running in opposite directions such that during a relative rotation in one direction of rotation the rings ( 26 , 28 ) are moved apart against the flat surfaces ( 22 , 24 ). 2. Tool according to claim 1, characterized in that the clamping section can be clamped in a shrink fit into the tool holder of the machine tool. 3. Tool according to claim 1 or 2, characterized in that the ramp sections are formed by a helical surface ( 34 , 36 ). 4. Tool according to one of claims 1 to 3, characterized in that the joining rings ( 26 , 28 ) engage one another in a form-fitting manner with ramp surfaces facing one another. 5. Tool according to one of claims 1 to 4, characterized in that the joining rings ( 26 , 28 ) have recesses ( 22 , 24 ) and the like on the outer circumference for the engagement of a tool for rotating the joining rings.