HYDRAULIC EXPANSION CHUCK

Abstract

The invention relates to a hydraulic expansion chuck comprising a main body (1) that extends along a rotational or longitudinal central axis (2) and is composed of a shaft part (20), for directly or indirectly coupling the hydraulic expansion chuck to a module of a modular tool system or to a machine spindle, and a clamping part (30), joined to the shaft part in a rotationally and axially fixed manner for receiving and clamping a shank tool. The shaft part comprises a receiving socket which extends towards the clamping part and has a central socket-opening in which a connection pin (31) of the clamping part, which pin extends towards the shaft part, is form-fittingly received. According to the invention, the clamping part comprises a stop which is radially offset from the connection pin and axially strikes the receiving socket.

Claims

1. A hydraulic expansion chuck comprising a base body, which extends along a rotational or longitudinal central axis and which is comprised of a shaft part for the direct or indirect coupling of the hydraulic expansion chuck to a module of a modular tool system or to a machine spindle, and a clamping part, which is joined to the shaft part in a rotationally and axially fixed manner, for receiving and clamping a shaft tool, wherein the shaft part has a receiving sleeve extending towards the clamping part comprising a central sleeve opening, in which a connecting pin of the clamping part, which extends towards the shaft part, is received in a positive manner, the clamping part having a stop, which is radially offset with respect to the connecting pin and which axially strikes against the receiving sleeve.

2. The hydraulic expansion chuck according to claim 1, wherein the stop abuts flat against the receiving sleeve.

3. The hydraulic expansion chuck according to claim 2, wherein the stop has a ring-shaped or ring segment-shaped stop surface, which abuts against the receiving sleeve on a front-side counter surface.

4. The hydraulic expansion chuck according to claim 1, wherein the clamping part is connected in a positive manner, non-positive manner and/or by means of a substance-to-substance bond, to the shaft part.

5. The hydraulic expansion chuck according to claim 1, wherein the connecting pin has a guide portion, which can be axially inserted into the receiving sleeve.

6. The hydraulic expansion chuck according to claim 1, wherein the connecting pin has an externally threaded portion, which can be axially screwed into the receiving sleeve.

7. The hydraulic expansion chuck according to claim 1, wherein the receiving sleeve has a reduced diameter compared to a longitudinal portion of the shaft part facing away from the clamping part.

8. The hydraulic expansion chuck according to claim 1, wherein the receiving sleeve conically tapers from a longitudinal portion of the shaft part, which faces away from the clamping part, towards the clamping part.

9. The hydraulic expansion chuck according to claim 1, wherein the clamping part connects in a radially flush manner to the receiving sleeve.

10. The hydraulic expansion chuck according to claim 1, wherein the clamping part has at least one pressure chamber, to which fluid pressure can be applied and which is connected to a pressure source arranged in the shaft part via a pressure duct, and the pressure duct leads over a joining gap, which corresponds to an axial play, between a front surface of the connecting pin facing the shaft part, and a base surface of the sleeve opening, which faces the clamping part.

11. The hydraulic expansion chuck according to claim 10, wherein the pressure duct is sealed in the region of the joining gap.

12. The hydraulic expansion chuck according to claim 11, wherein the pressure duct is sealed by means of a pair of annular seals, which are arranged between the front surface of the connecting pin and the base surface of the sleeve opening.

13. The hydraulic expansion chuck according to claim 11, wherein the pressure duct is sealed by means of a pair of annular seals, one annular seal of which is arranged between the front surface of the connecting pin and the base surface of the sleeve opening, and the other annular seal is arranged between a jacket surface of the connecting pin and an inner surface of the sleeve opening.

14. The hydraulic expansion chuck according to claim 10, wherein the chuck further comprises a ventilation duct, which connects the at least one pressure chamber to a ventilation means.

15. The hydraulic expansion chuck according to claim 14, wherein the ventilation means is arranged in the shaft part.

16. The hydraulic expansion chuck according to claim 14, wherein the ventilation duct and the pressure duct lie offset to one another by 180° with respect to the rotational or longitudinal central axis.

17. The hydraulic expansion chuck according to claim 1, wherein the shaft part and/or the clamping part are in each case made monolithically.

18. The hydraulic expansion chuck according to claim 1, wherein the chuck further comprises a central opening axially passing through the shaft part and the clamping part.

19. The hydraulic expansion chuck according to claim 1, wherein the shaft part has a hollow shaft.

20. The hydraulic expansion chuck according to claim 1, wherein an axial stop is arranged in the clamping part in particular in the form of an adjusting screw, which is screw-connected to the clamping part, for a shaft tool, which is to be received in the clamping part.

21. The hydraulic expansion chuck according to claim 4, wherein the clamping part is screw-connected and/or welded to the shaft part.

22. The hydraulic expansion chuck according to claim 17, wherein the shaft part and/or the clamping part are in each case made additively.

23. The hydraulic expansion chuck according to claim 1, wherein an axial stop is arranged in the clamping part, in the form of an adjusting screw, which is screw-connected to the clamping part, for a shaft tool, which is to be received in the clamping part.

Description

[0018] The present invention will be described below on the basis of enclosed drawings.

[0019] FIG. 1 shows a half section of a hydraulic expansion chuck according to the invention according to a first embodiment along a rotational or longitudinal central axis.

[0020] FIG. 2 shows a section of a hydraulic expansion chuck according to the invention according to the first embodiment transversely to the rotational or longitudinal central axis at a point, which is specified with B-B in FIG. 1.

[0021] FIG. 3 shows a partial section of the hydraulic expansion chuck according to the invention according to the first embodiment along the rotational or longitudinal central axis in a plane, which is specified with E-E in FIG. 2.

[0022] FIG. 4 shows a partial section of a hydraulic expansion chuck according to the invention according to a second embodiment along the rotational or longitudinal central axis in a plane, which is specified with E-E in FIG. 2.

[0023] FIGS. 1 to 3 show a first embodiment of a hydraulic expansion chuck according to the invention.

[0024] The hydraulic expansion chuck according to the invention comprises a base body 1, which extends along a rotational or longitudinal central axis 2. The base body 1 is comprised of a shaft part 20 and a clamping part 30, which is axially attached to the shaft part 20.

[0025] The shaft part 20 is provided to connect the base body 1 on the side facing away from the clamping part 30 to a (non-illustrated) module of a modular tool system or of a (non-illustrated) machine spindle.

[0026] As is shown in FIG. 1, the shaft part 20 has, for this purpose, a hollow shaft 23 on the side facing away from the clamping part 30. In the shown embodiment, the hollow shaft 23 is formed by a HSK shaft, which is known per se to the person of skill in the art.

[0027] On the side facing the clamping part 30, the shaft part has a receiving sleeve 21 extending along the rotational or longitudinal central axis 2 towards the clamping part 30 comprising a central sleeve opening, as is shown in FIG. 3. FIG. 3 shows that the receiving sleeve 21, i.e. the upper longitudinal portion of the shaft part in FIG. 3, slightly tapers conically towards the clamping part 30 and that the diameter thereof is consistently smaller than the lower longitudinal portion of the shaft part in FIG. 3.

[0028] The front side of the receiving sleeve 21 located on the top in FIG. 3 forms a counter surface 22, against which a stop surface 32, which is provided at the clamping part 30, abuts in an axially flush manner. In the first embodiment, the counter surface 22 is formed in a circular ring-shaped manner and lies in a cross sectional plane of the base body 1.

[0029] The sleeve opening can be divided axially into an inner receiving portion, which is formed in a circular cylindrical manner in the shown first embodiment, and an outer internally threaded portion 27.

[0030] The clamping part 30 is provided for receiving and hydraulically clamping a (non-illustrated) shaft tool, such as, for instance, a drill or milling tool, in a central receiving opening 35. On the side facing the shaft part 20, the clamping part 30 has a connecting pin 31, which extends towards the shaft part 20 and which is received in an accurately fitting manner in the receiving sleeve 21. For this purpose, the connecting pin 31 has, corresponding to the sleeve opening, a cylindrical guide portion, which sits in a radially positive manner in the receiving portion of the sleeve opening, as well as an externally treaded portion 37, which is screwed into the internally threaded portion 27. As shown in FIG. 3, the externally threaded portion 37 of the clamping part 30 is screwed into the internally threaded portion 27 of the receiving sleeve 21 so deeply that the clamping part 30 strikes against the above-mentioned shaft part-side counter surface 22 with a front-side stop surface 32 facing the shaft part and encasing the connecting pin 31. The stop surface 32, which is formed in a circular ring-shaped manner in the first embodiment, forms a stop according to the claim, which limits the insertion depth of the clamping part 30 in the shaft part 20 and thus defines the axial position of the clamping part 30 at the shaft part 20 and the axial total length of the base body 1 or hydraulic expansion chuck, respectively.

[0031] FIG. 3 shows that the clamping part 30 connects in a radially flush manner to the receiving sleeve 21, and how the receiving sleeve 21 is slightly tapered conically. FIG. 3 furthermore shows that the clamping part 30 is additionally connected by means of a substance-to-substance bond by means of welding to the shaft part 20 in the contact region of the clamping part-side stop surface 32 and the shaft part-side counter surface 22. In the joining state shown in FIG. 3, the connecting pin 31 extends so far into the receiving sleeve 21 that a front surface 36 of the connecting pin 31 facing the shaft part 20 is spaced apart from a base surface 26 of the sleeve opening facing the clamping part 30 by a narrowly designed axial play or a narrowly dimensioned joining gap 3. The narrowly dimensioned joining gap 3 ensures the axial abutment of the stop surface 32, which encases the connecting pin 31, against the clamping part 30 at the counter surface 22, which encases the sleeve opening, of the receiving sleeve 21 of the shaft part. The axial length of the connecting pin 31 is therefore smaller than the depth of the sleeve opening of the receiving sleeve 21 by the axial play.

[0032] FIG. 3 furthermore shows a central opening 33, which axially passes through the clamping part 30 and shaft part 20. This central opening 33 connects a hollow space of the hollow shaft 23 to the central receiving opening 35 in the clamping part 30, and serves for the supply of a shaft tool, which is clamped in the clamping part 30, with a cooling lubricant fluid. To set the receiving depth of the shaft tool, the clamping part 30 furthermore has an axial stop, which is formed by an adjusting screw 34. The central opening 33 leads through the adjusting screw 34.

[0033] Around the central receiving opening 35, the clamping part 30 has two pressure chambers 40, to which fluid pressure can be applied, in the shown embodiment. The two pressure chambers 40 are connected to one another via an eccentrically located connecting duct 41. A pressure duct 42 and a ventilation duct 44 in each case lead into the pressure chamber 40, which is located closer to the shaft part 20, wherein they run towards a pressure source 43 or a ventilation means 45, respectively, which are shown in FIG. 2, in the direction of the rotational or central longitudinal axis 2 as well as eccentrically to the central opening 33. The pressure duct 42 and the ventilation duct 44 are offset to one another by essentially 180° with respect to the rotational or longitudinal central axis 2.

[0034] As shown in FIG. 2, the portion of the pressure duct 42, which is arranged in the shaft part 20, is connected to a pressure source 43, which is arranged in the shaft part 20, and the portion of the ventilation duct 44, which is arranged in the shaft part 20, is connected to a ventilation means 45, which is arranged in the shaft part 20.

[0035] In the embodiment shown in FIG. 3, the pressure duct 42 and the ventilation duct 44 are sealed at the transition between the front surface 36 and the base surface 26, i.e. in the region of the joining gap 3, by means of a pair of annular seals 50.

[0036] In the first embodiment shown in FIG. 3, two copper sealing rings are arranged between the front surface 36 and the base surface 26, which are in each arranged around the openings of the pressure duct 42 and ventilation duct 44 between the front surface 36 and the base surface 26, and which are pressed between the two surfaces. The required pressing pressure is attained by means of the screw-connection of the clamping part 30 with the shaft part 20.

[0037] As can be seen from the different shadings in FIG. 3, the shaft part 20 and the clamping part 30 were initially fabricated separately from one another and were joined subsequently in the shown embodiment. The clamping part 30, which, with the two pressure chambers 40, the pressure duct 42, the ventilation duct 44, etc., has more complex hollow structures, can be fabricated additively, e.g., by means of a 3D printing process. The shaft part 20 can likewise be manufactured additively, but for economical reasons, it can also be fabricated in a conventional manner by means of machining of a metallic body, because, with the portions of the pressure duct 42 and ventilation duct 44, which are essentially linear here, the receiving sleeve 21, the hollow shaft 23, etc., it has hollow structures, which can be realized more easily. FIG. 4 shows a second embodiment of a hydraulic expansion chuck according to the invention, which only differs from the first embodiment in the manner of the sealing of the pressure and ventilation duct 44, which leads over the joining gap 3.

[0038] In the case of the second embodiment shown in FIG. 4, two O-rings made of rubber are provided instead of the two copper sealing rings as annular seals 50. One of the two O-rings is thereby arranged radially within the openings of the pressure duct 42 and ventilation duct 44 between the front surface 36 and the base surface 26, and the other one of the two O-rings is arranged between the jacket surface of the guide portion of the connecting pin 31 and the inner surface of the receiving portion of the receiving sleeve 21. In the second embodiment, the clamping part 30 is furthermore not screw-connected to the shaft part 20. The connecting pin 31 is thus only formed from one guide portion, while the sleeve opening of the receiving part is only formed from one receiving portion. To ensure a rotationally and axially fixed fastening of shaft part 20 and clamping part 30, a substance-to-substance bond by means of, e.g., welding, soldering, or the like, of the counter surface 22 and stop surface 32, which touch one another, is thus required.

[0039] Deviations from the above-described embodiments are possible within the scope of protection of the claims.

[0040] In addition to a screw-connection by means of threaded portions, which are formed integrally with the shaft part 20 or clamping part 30, respectively, the rotationally and axially fixed connection of shaft part 20 and clamping part 30 can thus also take place by means of axial screw-connection with the help of several screws or the like.

[0041] Instead of the two pressure chambers 40 shown in FIGS. 3 and 4, one, three, four, or more pressure chambers 40 can furthermore be provided.

[0042] The axial length of the connecting pin 31 can furthermore be essentially identical to the axial depth of the sleeve opening, the front surface 36 of the connecting pin 31 can thus abut more or less flush against the base surface 26 of the sleeve opening. A joining gap 3 between the front surface 36 of the connecting pin 31 and the base surface 26 of the sleeve opening is thus not absolutely necessary, as long as an abutment of the clamping part-side stop against the receiving sleeve 21 of the shaft part is ensured. [0043] 1 base body [0044] 2 rotational or longitudinal central axis [0045] 3 joining gap [0046] 20 shaft part [0047] 21 receiving sleeve [0048] 22 counter surface [0049] 23 hollow shaft [0050] 26 base surface [0051] 27 internally threaded portion [0052] 30 clamping part [0053] 31 connecting pin [0054] 32 stop surface [0055] 33 central opening, which passes through [0056] 34 adjusting screw [0057] 35 receiving opening [0058] 36 front surface [0059] 37 externally threaded portion [0060] 40 pressure chambers [0061] 41 connecting duct [0062] 42 pressure duct [0063] 43 pressure source [0064] 44 ventilation duct [0065] 45 ventilation means [0066] 50 annular seals