DE102021105405A1 - Tool holder and method for its manufacture - Google Patents

Abstract

Tool holder (1) should include: A tool holder (2) for receiving a tool (15), an outer cone (3) for inserting the tool holder (1) into an inner cone (8) of a collet holder (6) and an internal thread (4) for Fixing of the tool holder (1) on an external thread (7) of a collet holder (6).

Description

technical field

The invention relates to a tool holder and a method for its production.

State of the art

In the prior art, tools such as drills or end mills for CNC automatic lathes are fastened in so-called collet holders inside the CNC automatic lathe by inserting a collet into an inner cone of the collet holder, inserting the tool into the collet, and both then by tightening a clamping nut is fixed.

With such a system, changing tools is often difficult and tedious, resulting in long downtimes.

Furthermore, when the clamping nut is tightened, there is generally an unwanted axial displacement of the tool relative to the collet holder due to the compression of the collet. Tightening the clamping nut not only leads to a force acting radially inward, with which the tool is positively fixed within the collet, but also to a certain movement of the tool in the longitudinal direction (axial). The motors of the CNC automatic lathe only control the collet holders. If a selected axial position, in which the tool is fixed relative to the collet holder, is changed by tightening the clamping nut, this inevitably leads to poorer working results. After all, the CNC automatic lathe does not "know" that the axial position of the tool has changed during tightening. Compensation for this change in axial position is only possible if the amount of the change is known and is transferred manually to the controller, which is very cumbersome.

Furthermore, chips and other contaminants often accumulate within the expansion slots of known collets, which are always present. In particular, insufficient cleaning of the collet can lead to incorrect clamping of the tool, which in turn causes a concentricity error.

object of the invention

The object of the present invention is to overcome the disadvantages of the prior art.

solution of the task

The objects of the independent claims lead to the solution of the problem. Advantageous configurations are described in the dependent claims.

A tool holder according to the present invention comprises a tool holder for receiving a tool, an outer cone for inserting and centering the tool holder in an inner cone of a known collet holder and an internal thread for fixing the tool holder to an external thread of the collet holder.

Compared to known systems comprising a collet holder, a collet and a clamping nut, there is the advantage that the tool can also be fixed in the tool holder outside of a CNC automatic lathe. This is then only screwed onto the external thread of the collet holder.

Since the collet holder is always inside the CNC automatic lathe during normal operation and is only removed for maintenance purposes and tool changes, it is not possible to fix the tool outside of the CNC automatic lathe when using known collets. When using known collets, the tool is fixed in the collet only when the clamping nut exerts pressure on the collet so that it is pressed into the inner cone of the collet holder and the expansion slots become smaller. In known systems, however, this only happens when the clamping nut is screwed onto the external thread of the collet holder.

In contrast to this, the tool in the tool holder according to the invention can already be axially positioned and fixed outside of the CNC automatic lathe.

Fixing the tool in the tool holder outside of the CNC lathe also reduces the risk of injury to the operator. This risk of injury is always increased when work has to be carried out inside the machine.

Since collets can be dispensed with when using the tool holder according to the invention, there is also no risk of the collet being soiled by chips, dirt, etc. and, for example, chips getting into the expansion slots so that the clamping is incomplete and/or asymmetrical when the tool is changed . In particular, the erfindungsge includes If tool holders do not have small gaps or slits similar to the expansion slits of collets, which are predestined dirt traps due to their size.

The tool holder according to the invention enables quick tool changes and reduced downtimes.

The tool holder is primarily used in CNC automatic lathes, but can also be used in other machines.

The tool can be a drill, center drill, reamer, end mill or the like, which are used in CNC automatic lathes.

Collet holders are standard parts of CNC automatic lathes, for example. They are sometimes also referred to as straight shanks, taper shanks, milling tool holders, straight shank collet chucks, etc. Characteristic of such collet holders is the construction of an essentially cylindrical part which has an external thread and an internal cone at one end, this internal cone usually having a smooth surface.

The outer cone of the tool holder according to the invention is preferably designed to complement the inner cone of the collet holder.

The collet holder described above is not a necessary part of the tool holder according to the invention. Rather, the tool holder according to the invention is intended for use with known collet holders.

Advantageously, the outer cone of the tool holder can be based on the dimensions of known collets, which are specified in numerous industrial norms and standards and are described, for example, with a so-called ER nomenclature. Known collets have an outer contour which forms a cone so that they can be inserted into the inner cone of the collet holder. The outer cone of the tool holder according to the invention is modeled on the outer cone of known collets. The tool holder according to the invention can thus replace the collets used hitherto without replacing the collet holder.

The tool holder can be an axially extending cylindrical bore in the center of the tool holder. "Axial" here refers to the longitudinal direction of the tool holder, which corresponds to the longitudinal direction of the collet holder in relation to the installed state.

The tool holder can include a radially running internal thread, which can accommodate a stud screw or the like for fixing the tool. In this context, radial means orthogonal to the longitudinal direction described above. In addition to stud screws, such an internal thread can also accommodate other fixing means for fixing, which can fix the tool in the tool holder. In this context, fixing means securing the tool against unwanted rotation and against a translatory movement in the longitudinal direction of the tool holder.

It can be considered that the tool holder includes exactly one, exactly two, exactly three, exactly four or more such internal threads for fixing the tool. If there is more than one such internal thread, the internal threads are preferably distributed equidistantly over the circumference of the tool holder.

The advantage of the at least one internal thread for fixing is that no undesired axial movement of the tool relative to the tool holder takes place during the fixing. As already described, when using collets, such an undesirable axial movement takes place during the fixing of the tool. It should be mentioned here that this advantage is brought about not only by the internal threads for fixing, but also by the fact that, according to the present invention, collets are not used. However, the internal threads for fixation described above provide a very simple method for fixing the tool without undesired axial displacement.

The tool holder can be designed in such a way that the outer cone in cross section runs exclusively within the internal thread for fixing, and that in longitudinal section at least a section of the outer cone runs within the internal thread for fixing.

The tool holder can be made of at least two parts, wherein a first part in the longitudinal direction can include the outer cone on the one hand and the opening for inserting the tool on the other end and an outer thread in between for connection to a second part, the second part having the inner thread for fixing the tool holder can include on the external thread of the collet holder, wherein this internal thread can also serve to fix the connection to the first part.

The surface of the outer cone is preferably smooth.

Due to the at least two-part configuration, the tool holder can be manufactured very easily; standard manufacturing processes can be used. In the case of a one-piece production, the design of the outer cone, which is on the inside in cross-section, and the inner thread surrounding it, would be more complicated and therefore also more time-consuming and costly.

However, exemplary embodiments are also conceivable according to which the tool holder is manufactured in one piece.

The first part and the second part can have centering cones which are complementary to one another and which are in contact with one another in the assembled state and ensure that both parts are centered.

• - Bereitstellen des ersten und zweiten Teils sowie
• - Verbinden beider Teile durch Einschrauben des Aussengewindes zur Verbindung in das Innengewinde des zweiten Teils.

The present invention also includes a method for producing a tool holder as described above, comprising the following steps:

• - Provision of the first and second part as well as
• - Connect both parts by screwing in the external thread for connection into the internal thread of the second part.

The two parts are thus preferably connected to one another in a positive and non-positive manner, particularly preferably in a positive and non-positive manner.

However, exemplary embodiments can also be considered which additionally include a material connection, for example by connecting the two parts by means of spot welding, gluing or the like.

As already described, the advantage of this manufacturing method, which includes connecting the two parts, is that both parts can be manufactured simply and inexpensively and can be easily connected to one another.

character list

• Den 1 und 2 eine Spannzange 12 gemäss dem Stand der Technik und in den 3 bis 6 einen Werkzeughalter 1 gemäss einem Ausführungsbeispiel der vorliegenden Erfindung.

Further advantages, features and details of the invention result from the following description of preferred exemplary embodiments and from the drawings; these show in:

• The 1 and 2 a collet 12 according to the prior art and in the 3 until 6 a tool holder 1 according to an embodiment of the present invention.

example

1 shows a perspective exploded view of a collet holder 6, a collet 12 according to the prior art, a clamping nut 13 and a drill 15. An external thread 7 and an internal cone 8 of the collet holder 6 can also be seen.

2 shows the arrangement 1 in cut representation.

3a shows a collet holder 6 and a drill 15 after 1 and a perspective view of a tool holder 1 according to an exemplary embodiment of the present invention.

In 3b is the tool holder 1 after 3a shown from a different angle and in an exploded view.

In the 3a and 3b an outer cone 3, a radially running internal thread 5 for fixing and an opening 9 for inserting the drill 15 or the tool in general can also be seen.

the 3b until 6 show the two-part tool holder 1 comprising a first part 10 and a second part 11. The second part 11 is essentially designed as a union nut. 4a shows a sectional representation of the tool holder 1 after 4b . 5 shows a side view of the tool holder 1 according to the 4a and 4b in unassembled condition (exploded view). 6 shows the arrangement 5 in cut representation.

In the 4 until 6 a tool holder designed as a cylindrical bore 2 and an external thread 14 can also be seen. Furthermore, the outer cone 3 and the inner thread 4 can be seen for fixing.

• Der Bohrer 15 oder im Allgemeinen das Werkzeug wird in die Öffnung 9 des Werkzeughalters 1 eingeschoben und mittels einer Stiftschraube o.ä. (nicht gezeigt) im Werkzeughalter 1 fixiert, indem die Stiftschraube o.ä. durch das radial verlaufende Innengewinde 5 zur Fixierung eingedreht wird.

Referring to the 3a until 6 the functioning of the device according to the invention is explained as follows:

• The drill 15 or in general the tool is pushed into the opening 9 of the tool holder 1 and fixed in the tool holder 1 by means of a stud or the like (not shown) by screwing the stud or the like through the radial internal thread 5 for fixing becomes.

The tool holder 1 can be fixed in the collet holder 6 before or after receiving the drill 15 . The outer cone 3 of the tool holder 1 has a complementary shape to the inner cone 8 of the collet holder 6 . The inside thread 4 for fixing the tool holder 1 enables a connection with the external thread 7 of the collet holder 6.

In contrast, in known systems according to the 1 and 2 the fixing of the drill 15 relative to the collet 12 only takes place when the collet 12 has been introduced into the inner cone 8 of the collet holder 6 and has received the drill 15 . By subsequently tightening the clamping nut 13 , the collet 12 and the drill 15 are fixed relative to one another and relative to the collet holder 6 . In this case, there is always an undesired “pulling in” of the drill 15 into the inner cone 8, ie an axial displacement of the drill or, in general, of the tool.

the 5 and 6 show how the tool holder 1 is assembled from the two parts 10, 11 before it looks like in FIGS 4a and 4b shown. After the internal thread 4 has been connected to the external thread 14 to fix it, a positive and non-positive connection of the two parts 10, 11 can take place. This can be done by tightening with high torque or by introducing a solder, an adhesive or the like.

The manufacture of the 4a , 4b shown tool holder 1 is done by connecting the two in the 5 and 6 parts 10, 11 shown separately.

The two parts 10, 11 are produced separately because a one-piece production of the tool holder 1 by machining is not possible and other methods are only possible with great effort.

Reference List

1

tool holder

2

Tool holder / cylindrical bore

3

outer cone

4

Internal thread for fixing

5

Radial internal thread for fixation

6

collet holder

7

external thread

8th

inner cone

9

opening for insertion

10

first part

11

second part

12

collet

13

clamping nut

14

external thread

15

drill (tool)

16

inner thread

17

centering cone

Claims (7)

Tool holder (1) comprising a tool holder (2) for receiving a tool (15), an outer cone (3) for introducing the tool holder (1) into an inner cone (8) of a collet holder (6) and an internal thread (4) for fixing the tool holder (1) to an external thread (7) of a collet holder (6). Tool holder (1) according to claim 1 , characterized in that the tool holder (2) is an axially extending cylindrical bore in the center of the tool holder (1). Tool holder (1) according to claim 2 , characterized by at least one radially running internal thread (5) for receiving a stud for fixing the tool (15). Tool holder (1) according to at least one of the preceding claims, characterized in that the outer cone (3) in cross section runs exclusively inside the inner thread (4) for fixing, and that in longitudinal section at least a section of the outer cone (3) inside the inner thread (4 ) runs to the determination. Tool holder (1) according to at least one of the preceding claims, characterized in that the tool holder (1) is made of at least two parts (10, 11), a first part (10) in the longitudinal direction having the outer cone (3) at one end and the Opening (9) for inserting the tool (15) and between them an external thread (14) for connection to a second part (11), the second part (11) having the internal thread (4) for fixing the tool holder (1) to the External thread (7) of the collet holder (6), this internal thread (4) also serving to fix the connection to the first part (10). Tool holder (1) according to claim 5 , characterized in that the first part (10) and the second part (11) have mutually complementary centering cones (17) which in the assembled state are in contact with one another stand and ensure that both parts (10, 11) are centered. Method for producing a tool holder (1) according to at least one of Claims 5 until 6 , characterized by the following steps: - providing the first and second parts (10, 11) and - connecting both parts (10, 11) by screwing in the external thread (14) for connection into the internal thread (4) of the second part (11).

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