HYDRAULIC EXPANSION CHUCK

Abstract

A hydraulic expansion chuck for accommodating a machining tool, comprising a main chuck body that has a first chuck portion for fastening to a chuck connection as well as a second chuck portion for clamping the machining tool, wherein the second chuck portion includes a substantially cylindrical cavity, and wherein at least a first chamber and a second chamber for holding a fluid are arranged within the second chuck portion in such a way as so peripherally surround at least some sections of the cavity, and said first chamber and second chamber are designed in such a way as to bulge and reduce a cross-section of the cavity in at least some sections when the pressurized fluid is admitted into the chambers, the first chamber and the second chamber being positioned at an angle to one another.

Claims

1. A hydraulic expansion chuck for accommodating a machining tool comprising a main chuck body with a first chuck portion for fastening to a chuck connection, and a second chuck portion for bracing the machining tool, wherein the second chuck portion comprises an essentially cylindrical cavity, and wherein at least a first chamber and a second chamber for accommodating a fluid are arranged within the second chuck portion in order to circumferentially enclose the cavity at least in sections, and which the first chamber and the second chamber are formed in order to bulge during the pressurized admittance of the fluid and in order to decrease a cross section of the cavity at least in sections, and wherein the first chamber and the second chamber are arranged at an angle (α) to one another.

2. The hydraulic expansion chuck according to claim 1, wherein the angle (α) is between 2° and 10°.

3. The hydraulic expansion chuck according to claim 1, wherein the first chamber and the second chamber are directly connected to one another.

4. The hydraulic expansion chuck according to claim 1, wherein the second chamber is arranged at an angle (β) of between 2° and 10° to the cavity.

5. The hydraulic expansion chuck according to claim 1, wherein the cavity comprises a first essentially cylindrical cavity portion with a diameter D.sub.1 and a second essentially cylindrical cavity portion with a diameter D.sub.2≠D.sub.1, and wherein the first cavity portion and the second cavity portion are indirectly or directly connected to one another.

6. The hydraulic expansion chuck according to claim 5, wherein the first cavity portion and the second cavity portion are indirectly connected to one another by a third portion, wherein the third portion is formed as essentially an L- or S-shaped ledge.

7. The hydraulic expansion chuck according to claim 6, wherein the second chamber is arranged in order to enclose the third portion.

8. The hydraulic expansion chuck according to claim 1, comprising at least one fluid inlet, which fluid inlet connects an outer side of the hydraulic expansion chuck to the first chamber and/or the second chamber.

9. The hydraulic expansion chuck according to claim 1, wherein a third chamber, which is connected to the first chamber via at least one channel arranged within the second chuck portion, is arranged within the second chuck portion.

10. The hydraulic expansion chuck according to claim 9, wherein the first chamber, the second chamber, and the third chamber are arranged between 0.1 mm and 2 mm spaced apart from an outer side of the cavity.

11. The hydraulic expansion chuck according to claim 1, wherein the first chamber has a length L.sub.1 and the second chamber has a length L.sub.2, wherein the ratio L.sub.1:L.sub.2 is between 1:2 and 2:1.

Description

[0018] FIG. 1 shows a sectional view of the hydraulic expansion chuck; and

[0019] FIG. 2 shows a detailed view onto a part of the hydraulic expansion chuck from FIG. 1.

[0020] FIG. 1 shows a sectional view of the hydraulic expansion chuck 1 for accommodating a machining tool. The hydraulic expansion chuck 1 comprises a main chuck body 2 with a first chuck portion 21 for fastening to a chuck connection, and a second chuck portion 22 for bracing the machining tool. The second chuck portion 22 thereby comprises an essentially cylindrical cavity 4. A first chamber 31, a second chamber 32, and a third chamber 33 for accommodating a fluid are arranged within the second chuck portion 22 in order to circumferentially enclose the cavity in sections.

[0021] The first chamber 31 and the second chamber 32 are directly connected to one another. The third chamber 33 is connected to the first chamber 31 via a channel 34 arranged within the second chuck portion 22.

[0022] The chambers 31, 32, 33 are formed in order to bulge during the pressurized admittance of the fluid and in order to decrease a cross section of the cavity 4 in sections. A shaft of a machining tool introduced into the cavity can be braced thereby.

[0023] The first chamber 31 is arranged coaxially to the cavity. The second chamber 32 is arranged at an angle β (shown in FIG. 2) of 2° to the first chamber 31 and to the cavity 4.

[0024] The first chamber 31 thereby has a length L.sub.1 and the second chamber 32 has a length L.sub.2. The ratio L.sub.1:L.sub.2 is thereby between 1.2:1.

[0025] The first chamber 31, the second chamber 32, and the third chamber 33 are arranged between 0.2 mm and 0.6 mm spaced apart from an outer side 44 of the cavity 4. While the first chamber 31 and the third chamber 33 have a constant distance from the outer side 44, the second chamber has an increasing distance from the outer side 44, which results from the angled arrangement of the second chamber 32 relative to the cavity 4.

[0026] The first cylindrical cavity portion 4 has a diameter D.sub.1 and a second cylindrical cavity portion 42 has a diameter D.sub.2>D.sub.1. The first cavity portion 41 and the second cavity portion 41 are connected to one another by means of a third portion 43 (shown in FIG. 2).

[0027] The third portion 43 (shown in FIG. 2) is thereby formed as essentially L-shaped ledge with rounded corner.

[0028] The hydraulic expansion chuck 1 comprises two fluid inlets 5. The fluid inlets 5 in each case connect an outer side 11 of the hydraulic expansion chuck 1 to the first chamber 31.

[0029] FIG. 2 shows a detailed view A onto a part of the hydraulic expansion chuck from FIG. 1.

[0030] The first cavity portion 41 and the second cavity portion 42 are connected to one another by means of a third portion 43. The first chamber 31 is thereby arranged coaxially to the cavity 4. The second chamber 32 is arranged at an angle α=2° to the first chamber 31 and to the cavity 4. In the shown example, the angle α corresponds to the angle β. The second chamber 32 is arranged in order to enclose the third portion 43. The third portion 43 is thereby formed as essentially L-shaped ledge with rounded corner.

[0031] If the third chamber 43 bulges due to the pressurized admittance of the fluid, the ledge is moved in the direction of the cavity 4 and thus decreases the cross section thereof. If, for example, the shaft of a machining tool is introduced into the cavity 4, a particularly high clamping pressure, which optimally clamps the shaft, occurs, inter alia, at that point, at which the third portion 43 clamps the shaft.