EP3993930A1

EP3993930A1 - Hydraulic expansion chuck

Info

Publication number: EP3993930A1
Application number: EP20733273.5A
Authority: EP
Inventors: Simon Herzog; Christian Steidle; Andreas Löw; Martin GUTMACHER
Original assignee: Guehring KG
Current assignee: Guehring KG
Priority date: 2019-07-02
Filing date: 2020-06-16
Publication date: 2022-05-11
Also published as: DE102019209684A1; WO2021001140A1; US20220152709A1

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.

Description

DESCRIPTION

Hydraulic chucks

The invention relates to a hydraulic expansion chuck according to the preamble of claim 1.

Such a hydraulic expansion chuck is known, for example, from WO 2017/093280 A1 and has a base body which extends along a rotational or longitudinal center axis and which functionally extends into a clamping part (referred to as an expansion bushing in WO 2017/093280 A1) for receiving and clamping a Shank tool and a shank part (referred to as a base body in WO 2017/093280 A1) for direct or indirect coupling of the hydraulic expansion chuck to a module of a modular tool system or to a machine spindle.

The clamping part has two fluid pressure pressurizable pressure chambers around a central receiving opening, which are each separated from the receiving opening via an elastically flexible expansion wall and connected via a pressure channel to a pressure generating device arranged in the base body. When fluid pressure is applied to the pressure chambers, the expansion walls bulge ge conditions a received in the central receiving opening shaft tool, z. B. drill or milling cutter, in order to frictionally clamp the shaft tool received in the central receiving opening.

The shaft part has a receiving sleeve extending towards the clamping part (referred to as clamping part in WO 2017/093280 A1), which accommodates a connecting pin-like length section of the clamping part extending towards the shaft part. The axial position of the clamping part is adjustable by an axial stop provided in the shaft part, which is formed from a sleeve-shaped screw element and a sleeve-shaped elastic support element on which the clamping part is axially supported. The depth of immersion of the clamping part in the shaft part and thus the axial length of the hydraulic expansion chuck is determined by the screwing depth of the screw element in the shaft part, so that when assembling the hydraulic expansion chuck, care must be taken to ensure that the screw element is correctly positioned in the shaft part. The axial position of a shaft tool clamped in the clamping part is in turn adjustable by means of an adjusting screw screwed into the clamping part.

Based on the hydraulic expansion chuck specified in WO 2017/093280 A1, the present invention is based on the object of providing a hydraulic expansion chuck composed of a separately manufactured clamping and shaft part, which provides a precise fastening of the clamping part on the shaft part in the radial and axial direction and is therefore easier to manufacture.

This object is achieved by a hydraulic expansion chuck with the features of claim 1. Advantageous or preferred developments are the subject of dependent claims.

A hydraulic expansion chuck according to the invention comprises a base body extending along a rotary or longitudinal center axis, which consists of a shaft part for 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 attached to the shaft part in a rotationally and axially fixed manner Picking up and clamping a shank tool, e.g. B. drill or milling cutter is composed. The shaft part has a receiving sleeve extending towards the clamping part with a central sleeve opening in which a connecting pin of the clamping part extending towards the shaft part is received. The radial position of the clamping part on the shaft part is therefore set on the connection pin received in the receiving sleeve. For this purpose, the connecting pin can be positively received in the receiving sleeve with a defined radial play.

In contrast to the generic hydraulic expansion chucks discussed at the beginning, the clamping part according to the invention has a stop which is offset radially from the connecting pin and which strikes axially against the receiving sleeve. The ra dial offset stop ensures an easily achieved, clearly defined axial fixing of the clamping part on the shaft part. Furthermore, due to the radial offset of the stop from the connecting pin, an axial support of the clamping part on the shaft part is achieved, which is at a greater radial distance from the rotational or longitudinal center axis of the hydraulic expansion chuck than with the hydraulic expansion chuck discussed at the beginning, which creates a vibration-optimized, stable connection between Clamping part and shaft part is achieved. For this purpose, the stop on the clamping part side and the receiving sleeve are preferably designed in such a way that there is a flat contact of the stop on the receiving sleeve. The stop can, for example, a turned ring or ring segment-shaped, so z. B. have a circular ring, circular segment truncated cone or truncated cone segment-shaped stop surface, which rests precisely against egg ner facing the clamping part on the end face of the receiving sleeve. In particular, the stop surface can be a circular ring or a truncated cone surface that borders the connection pin and is continuous or interrupted in the circumferential direction. The mating surface on the receiving sleeve can be designed according to the stop surface on the clamping part.

In order to obtain a permanently fixed connection in the direction of rotation and in the axial direction, the clamping part can be non-positively and / or cohesively connected to the shaft part, in particular screwed and / or welded.

For this purpose, the connecting pin can have a guide section which can be inserted axially in a radially form-fitting manner into a receiving section of the sleeve opening. In addition, the connecting pin can have an externally threaded section which can be screwed axially into an internally threaded section of the receiving sleeve. The function of the guide section is to axially guide the connecting pin introduced into the receiving sleeve in the sense of a simple combination of clamping part and shaft part. For this purpose, the guide section and the receiving section can be designed to be cylindrical, preferably circular cylindrical, or (slightly) conically tapered towards the shaft part. The guide section is preferably received with a (closely) defined clearance fit in the receiving section of the sleeve opening. In the case of conical guide sections, the outer cone and inner cone are dimensioned and tolerated in such a way that the desired axial contact of the clamping part-side contact surface on the shank-part-side stop surface is always guaranteed. The above-mentioned external thread section enables, in addition or as an alternative to the guide section, an axial bracing between the clamping part and the shaft part. Furthermore, the clamping part can be welded to the shaft part in the contact area of the stop on the clamping part side and the receiving sleeve.

In order to reduce weight and unbalance, the receiving sleeve can be positioned opposite a longitudinal section of the shaft part facing away from the clamping part be reduced in diameter. For example, the receiving sleeve can taper conically from the longitudinal section of the shaft part facing away from the clamping part towards the clamping part. Furthermore, the clamping part can connect radially flush with the receiving sleeve.

The clamping part of the hydraulic expansion chuck has at least one pressure chamber which can be pressurized with fluid and which can be connected in a manner known per se to a pressure source via a pressure channel and to a ventilation device via a ventilation channel. The pressure source and / or venting device are / is advantageously arranged in the shaft part, as a result of which the radial expansion and thus the weight of the clamping part, which is more prone to vibrations, can be kept low. Furthermore, an imbalance due to an uneven mass distribution can be kept low. Taking this idea into account, the ventilation duct and the pressure duct can furthermore be offset from one another by essentially 180 ° with respect to the rotational or longitudinal center axis.

The pressure channel can lead via a joint gap corresponding to an axial play between an end face of the connecting pin facing the shaft part and a base area of the sleeve opening facing the clamping part in the receiving sleeve, the pressure channel preferably being sealed in the area of this joint. This seal can be followed by a pair of ring seals that pin between the end face of the connection facing the shaft part and the base face of the sleeve opening facing the clamping part in the receiving sleeve. Alternatively, one of the ring seals between the end face of the connecting pin facing the shaft part and the base surface of the sleeve opening in the receiving sleeve facing the clamping part and the other ring seal between a lateral surface of the connecting pin and an inner surface of the sleeve opening in the receiving sleeve can be arranged. The ring seals can be designed as ring seals made of copper in the first case mentioned above or made of another suitable material, e.g. B. metal or plastic. In the above-mentioned second case, the ring seals can be designed as O-rings made of rubber or some other elastic material. The shaft part and / or the clamping part of the hydraulic expansion chuck can be manufactured monolithically, in particular additively. 3D printing processes for additive manufacturing are now established in the field of tool technology and allow simple production of complex hollow structures such as the at least one pressure chamber, the pressure channel or the ventilation channel.

Furthermore, the hydraulic expansion chuck can have a central opening axially penetrating the shaft part and the clamping part, via which, for example, a shaft tool clamped in the clamping part can be supplied with a cooling lubricant. For this purpose, the shaft part of the hydraulic expansion chuck preferably has a hollow shaft to which the penetrating central opening adjoins. The hollow shaft is preferably designed as a hollow shaft cone (HSK) known to those skilled in the art, but can, for. B. also be designed as a steep taper (SK) - or Zy cylinder shaft.

Furthermore, in the clamping part of the hydraulic expansion chuck, an axial stop, e.g. B. an adjusting screw for a shank tool received in the clamping part be angeord net. The above-mentioned central opening can lead through the axial stop. The axial stop can be adjustable to adjust the depth of the shank tool in the clamping part.

The present invention is described below with reference to the accompanying drawings.

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 center axis.

Fig. 2 shows a section of the hydraulic expansion chuck according to the invention ge according to the first embodiment transversely to the rotational or longitudinal center axis at a point indicated in Fig. 1 with B - B.

3 shows a partial section of the hydraulic expansion chuck according to the invention according to the first embodiment along the rotational or longitudinal center axis in a plane indicated by E - E in FIG. 2.

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 center axis in a plane indicated by E - E in FIG. 2. 1 to 3 show a first embodiment of a hydraulic expansion chuck according to the invention.

The hydraulic expansion chuck according to the invention comprises a base body 1 extending along a rotary or longitudinal center axis 2. The base body 1 is composed of a shaft part 20 and a clamping part 30 axially attached to the shaft part 20.

The shaft part 20 is intended to connect the base body 1 on the side facing away from the clamping part 30 to a module (not shown) of a modular tool system or a (not shown) machine spindle.

As shown in FIG. 1, for this purpose the shaft part 20 has a hollow shaft 23 on the side facing away from the clamping part 30. In the embodiments shown, the hollow shaft 23 is formed by an HSK shaft known per se to the person skilled in the art.

On the side facing the clamping part 30, the shaft part 20 has a receiving sleeve 21 with a central sleeve opening, as shown in FIG. 3, which extends along the rotational or longitudinal center axis 2 towards the clamping part 30. Fig. 3 shows that the receiving sleeve 21, i. H. In Fig. 3, the upper Längenab section of the shaft part, slightly tapered towards the clamping part 30 and is consistently smaller in diameter than the lower length portion of the shaft part in Fig. 3.

The in Fig. 3 overhead end face of the receiving sleeve 21 forms a Ge counter surface 22 against which a provided on the clamping part 30 stop surface 32 rests axially flush. In the first embodiment, the mating surface 22 is designed in the shape of a circular ring and lies in a cross-sectional plane of the base body 1.

The sleeve opening can be divided axially into an inner receiving section, which in the first embodiment shown has a circular cylindrical design, and an outer internally threaded section 27. The clamping part 30 is provided to take up a (not shown) shank tool such as a drill or milling cutter in a central receiving opening 35 and to clamp it hydraulically. The clamping part 30 has on the side facing the shaft part 20 to a connecting pin 31 extending towards the shaft part 20, which is received in the receiving sleeve 21 with an accurate fit. The connection pin 31 has for this purpose a cylindrical guide section corresponding to the sleeve opening, which sits in the receiving section of the sleeve opening in a radially form-fitting manner, as well as a male thread section 37 screwed into the internal thread section 27. As FIG. 3 shows, the externally threaded section 37 of the clamping part 30 is screwed so deeply into the internally threaded section 27 of the receiving sleeve 21 that the clamping part 30 with an end stop surface 32 facing the shaft part and enclosing the connecting pin 31 strikes against the abovementioned counter surface 22 on the shaft part . The annular stop surface 32 in the first embodiment forms a stop according to the claims, 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 on the shaft part 20 and the overall axial length of the base body 1 or hydraulic expansion chuck.

3 shows that the clamping part 30 adjoins the receiving sleeve 21 in a radially flush manner and, like the receiving sleeve 21, is slightly tapered. FIG. 3 further shows that the clamping part 30 is also materially connected to the shaft part 20 in the contact area of the clamping part-side stop surface 32 and the shaft part-side counter surface 22 by welding. In the joint state shown in Fig. 3, the connecting pin 31 extends so far into the receiving sleeve 21 that an end face 36 of the connecting pin 31 facing the shaft part 20 has a narrow axial play or a tightly dimensioned joint gap 3 from one of the Clamping part 30 facing base surface 26 of the sleeve opening is spaced apart. The tightly dimensioned joint gap 3 ensures the axial contact of the stop surface 32 enclosing the connecting pin 31 on the clamping part 30 on the mating surface 22 of the receiving sleeve 21 of the shaft part enclosing the sleeve opening. The axial length of the connecting pin 31 is accordingly smaller by the axial play than the depth of the sleeve opening of the receiving sleeve 21. FIG. 3 also shows a central opening 33 which axially penetrates the clamping part 30 and shaft part 20. This central opening 33 connects a flea space of the flea shaft 23 with the central receiving opening 35 in the clamping part 30 and is used to supply a shaft tool clamped in the clamping part 30 with a cooling lubricant fluid. To set the receiving depth of the shaft tool, the clamping part 30 also has an axial stop formed by an adjusting screw 34. The central opening 33 leads through the adjusting screw 34.

In the embodiment shown, the clamping part 30 has two pressure chambers 40 that can be acted upon by fluid pressure around the central receiving opening 35. The two pressure chambers 40 are connected to one another via an eccentric connec tion channel 41. A pressure channel 42 and a venting duct 44 each open into the pressure chamber 40, which is closer to the shaft part 20, these running in the direction of the rotational or longitudinal center axis 2 and eccentrically to the central opening 33 to a pressure source 43 or a venting device 45, which are shown in FIG 2 are shown. The pressure channel 42 and ventilation channel 44 are offset from one another by essentially 180 ° with respect to the rotational or longitudinal center axis 2.

As shown in Fig. 2, the section of the pressure channel 42 arranged in the shaft part 20 is connected to a pressure source 43 arranged in the shaft part 20, and the section of the ventilation channel 44 arranged in the shaft part 20 is connected to a ventilation device 45 arranged in the shaft part 20.

In the embodiment shown in FIG. 3, the pressure channel 42 and the ventilation channel 44 are at the transition between the end face 36 and the base surface 26, i.e. H. in the area of the joint gap 3, with a pair of ring seals 50 sealed.

In the first embodiment shown in Fig. 3, two copper sealing rings are arranged between the end surface 36 and the base surface 26, which are arranged between the end surface 36 and the base surface 26 around the openings of the pressure channel 42 and ventilation channel 44 and between the two surfaces are pressed. The required pressing pressure is achieved by screwing the clamping part 30 to the shaft part 20. As can be seen from the different hatching in FIG. 3, the shaft part 20 and the clamping part 30 in the embodiment shown were first manufactured separately from one another and then joined together. The clamping part 30, which has more complex hollow structures with the two pressure chambers 40, the pressure channel 42, the ventilation channel 44, etc., can, for. B. be manufactured additively by a 3D printing process. The shaft part 20 can also be manufactured additively, but for economic reasons it can also be manufactured in a conventional manner by machining a metal body, since it is here with the essentially linear sections of the pressure channel 42 and ventilation channel 44, the receiving sleeve 21, the Has hollow shaft 23, etc. easier to realize hollow structures. 4 shows a second embodiment of a hydraulic expansion chuck according to the invention, which differs from the first embodiment only in the way in which the pressure and ventilation duct 44 leading over the joint gap 3 is sealed.

In the second embodiment shown in FIG. 4, two O-rings made of rubber are provided as ring seals 50 instead of the copper sealing rings. Here is one of the two O-rings between the end face 36 and the Grundflä surface 26 radially inside the openings of the pressure channel 42 and ventilation channel 44 and the other of the two O-rings between the outer surface of the Führungsab section of the connecting pin 31 and the inner surface of the receiving portion of the Receiving sleeve 21 arranged. Furthermore, in the second embodiment, the clamping part 30 is not screwed to the shaft part 20. The connecting pin 31 is therefore only formed from a guide section, while the sleeve opening of the receiving part is formed only from a receiving section. Therefore, to ensure a rotationally and axially fixed attachment of the shaft part 20 and clamping part 30 is a material connection by z. B. welding, soldering or the like of the contacting mating surface 22 and stop surface 32 is required.

Deviations from the embodiments described above are possible within the scope of protection of the claims.

Thus, the rotationally and axially fixed connection of the shaft part 20 and the clamping part 30 can be made not only by screwing but also by means of axial screwing with the aid of several screws or the like, which are integral with the shaft part 20 or clamping part 30. Furthermore, instead of the two pressure chambers shown in FIGS. 3 and 4, 40 z. B. one, three, four or more pressure chambers 40 may be provided.

Furthermore, the axial length of the connecting pin 31 can be essentially the same as the axial depth of the sleeve opening, the end face 36 of the connecting pin 31 thus more or less flush with the base surface 26 of the sleeve opening. A joint gap 3 between the end face 36 of the connecting pin 31 and the base surface 26 of the sleeve opening is therefore not necessarily neces sary as long as the stop on the clamping part side abuts on the receiving sleeve 21 of the shaft part.

Base body

Rotary or longitudinal center axis joint gap

Shaft part

Receiving sleeve

Counter surface

Hollow shaft

Floor space

Internal thread section

Clamping part

Connecting pin

Stop surface

penetrating central opening set screw

Receiving opening

Face

External thread section

Pressure chambers

Connection channel

Pressure channel

Pressure source

Ventilation duct

Ventilation device

Ring seals

Claims

EXPECTATIONS

1. Hydraulic expansion chuck with a main body (1) extending along a rotary or longitudinal center axis (2), which consists of a shaft part (20) for direct or indirect coupling of the hydraulic expansion chuck to a module of a modular tool system or to a machine spindle and a rotating - and clamping part (30) attached axially fixed to the shaft part (20) for receiving and clamping a shaft tool, the shaft part (20) having a receiving sleeve (21) extending towards the clamping part (30) with a central sleeve opening, in which a connecting pin (31) of the clamping part (30) extending towards the shaft part (20) is positively received, characterized in that the clamping part (30) has a stop which is radially offset relative to the connecting pin (31) and which is attached the receiving sleeve (21) strikes axially.

2. Hydraulic expansion chuck according to claim 1, characterized in that the stop on the receiving sleeve (21) rests flat.

3. Hydraulic expansion chuck according to claim 2, characterized in that the stop has an annular or ring segment-shaped stop surface (32) which rests on an end-face mating surface (22) on the receiving sleeve (21).

4. Hydraulic expansion chuck according to one of the preceding claims, characterized in that the clamping part (30) with the shaft part (20) positively, non-positively and / or materially connected, in particular screwed and / or welded ver.

5. Hydraulic expansion chuck according to one of the preceding claims, characterized in that the connecting pin (31) has a guide section which can be axially inserted into the receiving sleeve (21).

6. Hydraulic expansion chuck according to one of the preceding claims, characterized in that the connecting pin (31) has an external thread section (37) which can be screwed axially into the receiving sleeve (21).

7. Hydraulic expansion chuck according to one of the preceding claims, characterized in that the receiving sleeve (21) opposite one of the Clamping part (30) facing away from the longitudinal section of the shaft part (20) is diameter-reduced.

8. Hydraulic expansion chuck according to one of the preceding claims, characterized in that the receiving sleeve (21) tapers conically from a longitudinal section of the shaft part (20) facing away from the clamping part (30) towards the clamping part (30).

9. Hydraulic expansion chuck according to one of the preceding claims, characterized in that the clamping part (30) connects radially flush with the receiving sleeve (21).

10. Hydraulic expansion chuck according to one of the preceding claims, characterized in that the clamping part (30) has at least one pressure chamber (40) which can be impacted with fluid pressure and which is connected via a pressure channel (42) to a pressure source (43) arranged in the shaft part (20) is, and the pressure channel (42) via a joint gap corresponding to an axial play (3) between an end face (36) of the connecting pin (31) facing the shaft part (20) and a base surface (26) facing the clamping part (30) Sleeve opening leads.

11. Hydraulic expansion chuck according to claim 10, characterized in that the pressure channel (42) is sealed in the region of the joint gap (3).

12. Hydraulic expansion chuck according to claim 11, characterized in that the pressure channel (42) is sealed by a pair of ring seals (50) which are arranged between the end face (36) of the connecting pin (31) and the base surface (26) of the sleeve opening.

13. Hydraulic expansion chuck according to claim 11, characterized in that the pressure channel (42) is sealed by a pair of ring seals (50), one of which is a ring seal between the end face (36) of the connecting pin (31) and the base (26) of the sleeve opening and the other ring seal is arranged between a lateral surface of the connecting pin (31) and an inner surface of the sleeve opening.

14. Hydraulic expansion chuck according to one of claims 10 to 13, marked is characterized by a ventilation duct (44) connecting the at least one pressure chamber (40) with a ventilation device (45).

15. Hydraulic expansion chuck according to claim 14, characterized in that the ventilation device (45) is arranged in the shaft part (20).

16. Hydraulic expansion chuck according to claim 14 or 15, characterized in that the ventilation duct (44) and the pressure duct (42) are offset from one another by 180 ° with respect to the rotational or longitudinal center axis (2).

17. Hydraulic expansion chuck according to one of the preceding claims, characterized in that the shaft part (20) and / or the clamping part (30) are each made monolithically, in particular additively.

18. Hydraulic expansion chuck according to one of the preceding claims, characterized by a shaft part (20) and the clamping part (30) axially penetrating central opening (33).

19. Hydraulic expansion chuck according to one of the preceding claims, characterized in that the shaft part (20) has a hollow shaft (21).

20. Hydraulic expansion chuck according to one of the preceding claims, characterized by an axial stop arranged in the clamping part (30), in particular in the form of an adjusting screw (34) screwed to the clamping part (30) for a shank tool to be received in the clamping part (30).