DE29612328U1 - Clamping nut for clamping tools - Google Patents

Description

G 8834 EN

Wolfgang Zürn

Uhlandstrasse 23

72144 Dusslingen

Clamping nut for clamping tool

The invention relates to a clamping nut for clamping tools with an eccentric inner ring that can be locked into a circumferential groove of a collet.

Such clamping nut and collet combinations are used in particular in drilling, milling, grinding and milling spindles where a high degree of concentricity is required. The eccentricity of the inner ring of the known clamping nuts is typically 1.6 mm to enable the collet to be easily inserted into the clamping nut. After inserting the collet into the clamping nut, the clamping nut is turned until the eccentric ring of the nut engages in the circumferential groove of the collet. When the clamping nut is loosened again, the collet can be pulled out of a collet holder of the clamping tool using the eccentric ring of the clamping nut. The relatively high eccentricity of 1.6 ram allows the use of collets with a clamping range of 1 mm each, but causes a corresponding imbalance, which severely affects the concentricity of the collet, particularly in rotation ranges above 5,000 rpm. For high speed ranges, there are also clamping nuts with centrifugal

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G 8834 EN

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see inner rings. However, only collets with a clamping range of 0.5 mm can be used with such inner rings. Collets with clamping ranges of 1 mm can no longer be pulled out of the collet holder by the nut in the case of clamping nuts with centric inner rings.

The present invention is based on the object of creating a clamping nut which enables exact concentricity even at very high speeds and with which collets with a clamping range of 1 mm can also be pulled out of the collet holder.

The object is achieved according to the invention with a clamping nut of the type mentioned at the outset in that the clamping nut has a material recess on the side opposite the eccentricity of the inner ring.

The imbalance caused by the eccentricity of the inner ring is compensated for in the clamping nut according to the invention by a material recess on the opposite side of the eccentricity of the inner ring. This ensures good concentricity even at very high speeds. Advantageously, the eccentricity of the inner ring can be selected to be less than 1.6 mm, preferably in the range of 0.6 mm. This means that the eccentricity and thus the material recess required to compensate for the imbalance is relatively small. The front side of the inner ring can be chamfered to make it easier to insert the collet. The angle of the chamfer to the horizontal can be approximately 30°. This ensures that the collet can be inserted without any problems even if the eccentricity of the inner ring is only 0.6 mm. An eccentricity of 0.6 mm ensures that collets with a 1 mm clamping range can be pulled out of the collet holder by the clamping ring, even with a minimum collet diameter.

G 8834 EN

The clamping nut can be constructed in two parts. It can be formed by a clamping nut housing with a clamping ring inserted into it, with the eccentric inner ring and the material recess arranged on the clamping ring. This two-part design of the clamping nut makes it easier to manufacture compared to a one-part design.

A preferred embodiment of a clamping nut according to the invention is explained in more detail below with reference to the drawing.

Shown: Fig. 1

a central longitudinal section through a clamping tool with a clamping nut according to the invention;

Fig. 2 Fig. 3

a front view of the clamping ring of the clamping nut according to Fig. 1;

a central longitudinal section through the clamping ring according to Fig. 2.

Fig. 1 shows a clamping nut 10 that is screwed onto a tool holder 11. The clamping nut 10 is formed by a clamping nut housing 12 and a clamping ring 13. The clamping nut housing 12 and the clamping ring 13 are connected to one another via a locking ring 14. A collet 15 is arranged inside the tool holder 11 and the clamping nut 10. The collet 15 has a circumferential groove 16 into which an eccentric inner ring 17 (Fig. 3) on the clamping ring 13 can be snapped. To make it easier to insert the collet 15 into the clamping nut 10, the inner ring 17 is eccentric. However, the eccentricity e of the inner ring 17 in the collet shown is only

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G 8834 EN

approx. 0.6 mm. The imbalance caused by the eccentricity e is compensated by a flattening 18 opposite the eccentricity e of the inner ring 17 and thus a material recess in the clamping ring 13. This ensures exact concentricity even at very high speeds of the clamping tool. In order to make it easier to insert the collet 15 into the clamping nut 10, the front side of the inner ring 17 is also chamfered, whereby in the example shown the chamfering angle α is 30°.

Claims (6)

1. Clamping nut for clamping tools with an eccentric inner ring (17) which can be locked into a circumferential groove (16) of a collet (15), characterized in that the clamping nut (10) has a material recess (18) on the side opposite the eccentricity (e) of the inner ring (17). 2. Clamping nut according to claim 1, characterized in that the eccentricity (e) of the inner ring (17) is less than 1.6 mm. 3. Clamping nut according to claim 3, characterized in that the eccentricity (e) of the inner ring (17) is preferably approximately 0.6 mm. 4. Clamping nut according to one of claims 1 to 3, characterized in that the end face of the inner ring (17) is chamfered to facilitate the introduction of the collet (15). 5. Clamping nut according to claim 4, characterized in that the angle (α) of the chamfer of the inner ring (17) to the horizontal is approximately 30 ^β . s :":»Sis « «♦ G 8834 EN 6. Clamping nut according to one of claims 1 to 5 , characterized in that the clamping nut (10) is formed by a clamping nut housing (12) and a clamping ring (13) inserted therein, the eccentric inner ring (17) and the material recess (18) being arranged on the clamping ring (13). DM/F