EP3344412A1

EP3344412A1 - Tool holder

Info

Publication number: EP3344412A1
Application number: EP16753335.5A
Authority: EP
Inventors: Gaston Schwenk; Jens Ketelaer; Manuel Praetorius
Original assignee: Sauer GmbH and Co KG
Current assignee: Sauer GmbH and Co KG
Priority date: 2015-08-31
Filing date: 2016-08-11
Publication date: 2018-07-11
Also published as: DE102015216596B4; RU2701252C1; DE102015216596A1; US20180264611A1; JP2018529531A; WO2017036757A1; KR20180096569A; CN108602136A

Abstract

The present invention relates to a tool holder 100 for accommodating a tool 200, having a housing 10, a transmitting element 20, arranged in a movable manner in the housing 10, for transmitting a movement to the tool 200 accommodated in a first end portion 30 of the tool holder 100, a fastening portion 40 at a second end portion 50 of the tool holder 100, located opposite the first end portion 30 of the tool holder 100, for fastening the tool holder 100 to a machine tool 300, and a coolant line portion 60 for conducting coolant from the second end portion 50 of the tool holder 100 to the first end portion 30 of the tool holder 100, wherein the coolant line portion 60 has a first section 61 extending through the transmitting element 20, wherein the first section 61 is configured at least in part as a bore in the transmitting element 20.

Description

TOOL HOLDER

The present invention relates to a tool holder for holding a tool, comprising a housing, a transmission member movably disposed in the housing for transmitting movement to the tool received at a first end portion of the tool holder, a fixing portion at a second end portion opposite to the first end portion of the tool holder the tool holder for fixing the tool holder to a machine tool, and a coolant conduit portion for guiding coolant from the second end portion of the tool holder to the first end portion of the tool holder.

BACKGROUND OF THE INVENTION

In the prior art tool spindles for use in a machine tool are known, which have a continuous inner tube for cooling and lubrication of the tool during workpiece machining, with which the coolant is passed to the tool. EP 1 480 783 B1 describes a machine tool having a spindle which has a tool holder for a replaceable tool holder, which is clamped in operation of the machine tool in the tool holder and which has a coolant tube for receiving a coolant lubricant, further having a inside of the spindle arranged first channel having an outlet opening, which opens within the tool holder, wherein the coolant tube engages with clamped tool holder in the outlet opening of the first channel, wherein the first channel includes a continuous inner tube, the first end is connected to an aerosol source and the second end to the accurate Connection to the coolant tube is formed.

In addition, tool holders for ultrasonic machining of workpieces are known, wherein the tool holder is caused to vibrate by a piezo system. EP 1 763 416 B1 describes a tool with a tool holder and a spindle nose, wherein the tool holder has a tool holder receptacle for adapting to the rotatable spindle nose at a first end, and a tool holder at a second end, and with a tool head insertable into the tool holder the tool holder and the spindle nose form a vibration motor and the vibration motor oscillates the tool holder via a piezo system and the piezo system comprises a first stationary coil and a second coil spaced therefrom and engaging the tool holder, the second coil having piezo coils. Actuators is connected.

When using a coolant tube in a vibrating tool holder, one end of the coolant tube in the direction of the spindle is fixedly connected to the housing of the oscillating tool holder. At the other end of the coolant tube in the direction of the tool, the tube must be sealed by means of a suitable sealing element accordingly. This sealing element is located close to the vibration node of the oscillating system in order to avoid loads on the sealing element due to the continuous oscillatory movement. However, in such an embodiment, the problem occurs that the pipe cross-section and the coolant flow to be achieved is too low to ensure optimum cooling of the tool. In addition, the vibration drive can not be cooled sufficiently well.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a tool holder with optimized coolant passage.

This object is achieved by a tool holder according to claim 1. The dependent claims relate to advantageous embodiments of the tool holder according to the invention.

The tool holder according to the invention for receiving a tool comprises: a housing, a transmission element arranged movably in the housing for transmitting a movement to the tool received at a first end portion of the tool holder, a fastening portion at a second, the first End portion of the tool holder opposite end portion of the tool holder for attaching the tool holder to a machine tool, and a coolant line for directing coolant from the second end portion of the tool holder to the first end portion of the tool holder, wherein the Kühlmittelleitungsabschnitt has a passing through the transmission element first portion, and wherein the first section is at least partially formed as a bore in the transmission element.

The coolant line section consists of the parts of the tool holder that come into contact with the coolant. If the coolant flows directly through the bore in the moving part of the toolholder instead of through a thin-walled, separate tube (which may easily be damaged during assembly, for example), this increases the stability of the design. For example, the transmission element can be vibrated and this vibration transmitted to the tool. The housing and the mounting portion of the tool holder do not swing with it. The coolant is thus passed on its way to the tool through a non-oscillating section and through a swinging portion of the tool holder. With the construction according to the invention can be dispensed with a double-walled coolant feedthrough, so that a larger cross-section can be used to direct the coolant to the tool, whereby the volume flow of the guided in the direction of the tool coolant can be increased. In addition, the pressure with which the coolant is passed through the coolant line section, can be increased due to the greater wall thickness of the coolant channel and the associated increased pressure resistance of the structure. As a result, the tool and portions of the tool holder in the vicinity of the bore can be better cooled. Ultimately, a higher precision in the workpiece machining is achieved.

The coolant line section preferably has a second partial section running through the fastening section, wherein the first partial section and the second partial section are arranged so as to be movable relative to one another.

This has the advantage that a movement of the transfer section, for example a vibration, relative to other parts of the tool holder by a corresponding movement of the first section of the coolant line section relative to the second Part section can be intercepted. The coolant line section may also consist of three or more sections, which are movable relative to each other.

The first partial section preferably has a first connecting section for connection to the second partial section at an end facing the second partial section, and the second partial section has a second connecting section for connection to the first partial section at an end facing the first partial section, wherein the first connecting section and the second connecting portion are joined together.

Such a design of the connection of both, mutually movable sections of the coolant line section has the advantage that the two connecting portions always overlap even with a movement of parts of the tool holder and is thus ensured that a continuous coolant channel is in the tool holder.

Preferably, the first connecting portion is formed as a hollow pin and arranged on the first portion of the Kühlleielleitungsabschnitts that the bore in the transmission element is continued by an interior of the hollow pin, and preferably the second connecting portion surrounds the first connecting portion circumferentially for introducing the coolant from the second portion in the first section.

This has the advantage that the coolant can be directed from the fixed or non-oscillating part of the tool holder into the movable or oscillating part of the tool holder without thereby seeping into the interior of the tool holder outside the coolant line section.

Preferably, the tool holder has a sealing element disposed between the first connecting portion and the second connecting portion for sealing against leakage of coolant from the coolant conduit portion.

This has the advantage that even with a movement of the connecting portions relative to each other no coolant can escape from the coolant line section. Preferably, the sealing element is designed as a ring made of plastic, which is connected to a Outside wall of the first connecting portion is pressed.

Thus, the connection between the first subsection and the second subsection of the coolant conduit section can be reliably sealed.

Preferably, the outer wall of the first connecting portion is ground.

This has the advantage that when the first connection section moves relative to the second connection section surrounding it, the first connection section does not catch on the second connection section, so that no mechanical stresses are created which can lead to damage of the sealing element.

Preferably, the tool holder has an ultrasonic transducer connected to the transmission element for generating an ultrasonic vibration for the tool, wherein the ultrasonic transducer, the transmission element and the first section of the coolant line section form a vibratory system in the housing, the coolant line section is arranged centrally in the tool holder, and Ultrasonic transducer surrounds the bore in the transmission element for cooling the ultrasonic transducer by the coolant in the bore at least partially.

Such an arrangement of the coolant-carrying elements of the tool holder and the ultrasonic transducer in the tool holder has the advantage that the coolant can be used not only to cool the tool, but also to cool the ultrasonic transducer. This is particularly important in order to prevent a heating-related change in the vibration parameters of the oscillatory system and the tool.

For a tool holder with a system capable of oscillating, in the design according to the invention, the sealing of the first and second connecting sections must take place at the point of maximum oscillation amplitude. Therefore, in such a tool holder, it is all the more important that the surface of the first connection portion is smooth ground to prevent abrasion of the sealing material. Preferably, the bore in the transmission element is formed so that the coolant passes through the transmission element using a flow cross-section of at least 4.9 mm ² and / or at a pressure of at least 60 bar. For example, the bore may have a diameter of 2.5 mm. Since with the structure according to the invention can be dispensed with an additional coolant tube in the bore, the full width of the bore can be used for passing coolant, resulting in a 20% higher volume flow compared to conventional coolant passages and to a pressure of the coolant from to leads to 80 bar in the tool holder. This increases above all the efficiency of the internal cooling, but also the tool cooling.

Preferably, the first subsection comprises a branch and the transfer section comprises a plurality of openings of the coolant conduit section such that the coolant is directed from the branch to the openings.

The openings in the form of side outlets are suitable for draining the coolant in tools such as drills or milling cutters that have no inner channel. In this case, the piezo drive is still cooled by the coolant volume flow. In addition, the relatively higher pressure can also be used for external cooling of the tool.

Preferably, the tool holder has a deflecting element arranged interchangeably on the tool holder for deflecting the coolant emerging from the openings in a direction of the tool received on the tool holder.

This has the advantage that such a rapid adaptation of the coolant jet geometry is achieved to the tool used. Preferably, the tool holder has a stabilizing element circumferentially around the first connecting portion and the second connecting portion for stabilizing a connection of the first portion of the refrigerant piping portion and the second portion of the refrigerant piping portion. This has the advantage that the area of the tool holder in which the sections of the coolant line section are connected becomes more stable.

Preferably, the coolant is air or water or an emulsion.

Air and water have the advantage that they can be provided cheaply. An emulsion has the advantage that its lubricating effect is high.

A machine tool according to the invention has the tool holder according to the invention, wherein the tool received in the tool holder and arranged in the housing of the tool holder parts of the tool holder along an axial direction of the tool holder during a workpiece processing by the coolant in the coolant line section can be cooled. BRIEF DESCRIPTION OF THE FIGURES

Fig. 1 shows an embodiment of a tool holder according to the invention as a sectional view.

Figs. 2A / B show a further embodiment of an inventive

Tool holder as a sectional view.

DETAILED DESCRIPTION OF THE FIGURES AND THE PREFERRED EMBODIMENTS OF THE PRESENT INVENTION In the following, the present invention will be described and explained in detail by means of exemplary embodiments and the exemplary figures.

Fig. 1 shows an embodiment of a tool holder 100 according to the invention as a sectional view. The tool holder 100 is formed as a longitudinal member having a first end portion 30 and a second end portion 50 facing the first end portion 30. At the first end portion 30, a tool 200 (not shown) may be received. At the second end portion 50, a mounting portion 40 is formed, by means of which the tool holder 100 can be replaceably attached to a machine tool 300. The tool holder 100 has a housing 10 in which a vibratory system comprising an ultrasonic transducer 70 and a transmission element 20 is disposed. The ultrasonic transducer 70 has stacked disc-shaped piezo elements that are excited by a generator (not shown) to a mechanical ultrasonic vibration. This vibration is transmitted by the mechanical coupling of the ultrasonic transducer 70 with the transmission element 20 to the transmission element 20 and from there to the tool 200.

For the purpose of tool cooling and lubrication in machining a workpiece, the tool holder 100 has a coolant conduit section 60 through which coolant from an opening of the coolant conduit section 60 in the region of the attachment section 40 through the tool holder 100 toward an opening of the coolant conduit section 60 in the region of the transfer section 20 is passed and exits under pressure from this.

In the transmission element 20, a first section 61 of the coolant line section 60 is formed as a bore, to which a first connection section 63 in the form of a hollow post adjoins. The hollow pin 63 is circumferentially surrounded by a second connecting portion 64, which may be formed as a portion of a pipe. The second connecting portion 64 has for this purpose an inner diameter which is only slightly larger than the outer diameter of the hollow pin 63. The opening of the hollow pin 63 is positioned within the second connecting portion 64 away from an opening of the connecting portion 64. The cavity in the second connection section 64 is part of a second section 62 of the coolant line section 60, which adjoins the first section 61 of the coolant line section 60. The cavity in the second connection portion 64 may be continued through a channel in a transition section 66 of the coolant line section 60. The channel may be continued through a length of pipe 67 which is connected to a device (not shown) which introduces coolant into the tool holder 100. In this embodiment, the channel in the transition section 66 and the pipe section 67 are also part of the second section 62 of the coolant line section 60. In this way, coolant can be conveyed from the second end section 50 of the tool holder 100 through the entire length of the coolant line section 60 to the tool 200 at the first End section 30 of the tool holder 100 are passed.

In an ultrasonic vibration of the oscillatory system, the parts of the tool holder 100 that form the first section 61 of the coolant line section 60, ie, the transmission section 20 and the hollow pin 63, oscillate. The parts of the tool holder 100 forming the second section 62 of the coolant conduit section 60 vibrate Not. Thus, the hollow pin 63 performs a vibration in the second (non-oscillating) connecting portion 64. Thus, the hollow pin 63 and the second connecting portion 64 do not come into direct mechanical contact, the pin wall is ground and in the annular space between the hollow pin 63 and the second connecting element 64, a sealing element 65th pressed in the form of an O-ring to the hollow pin 63. The sealing ring 65 thus ensures a small minimum distance between the hollow pin 63 and the second connecting portion 64 and seals the connection between the first section 61 and the second section 62 of the coolant line section 60 against leakage of coolant from the coolant line section 60.

The coolant flows directly into the bore of the transfer section 20. As a result, the entire diameter of the bore of, for example, 2.5 mm, ie a cross-sectional area of, for example, 4.9 mm ² , be used for passing the coolant. The wall formed by the transfer element 20 around the bore is relatively thick (thicker than the bore diameter). In addition, a stabilizing element 80 is arranged in the housing 10 around the second connecting section 64 and around a part of the transition section 66. Thus, voids within the housing 10 that are not part of the coolant line section 60 are largely avoided. As a result, the coolant can be passed through the tool holder 100 at a high pressure of up to 80 bar.

The ultrasonic transducer 70 is arranged as a ring element around the bore in the transmission section 20, without there being a cavity between the bore and the ultrasonic transducer 70 in the radial direction. The coolant flowing through the transfer section 20 thus provides cooling of the wall around the bore and the direct mechanical contact of the transfer section 20 with the ultrasonic transducer 70, thus also for cooling the ultrasonic transducer 70. Figs. 2A and 2B show another embodiment of a tool holder according to the invention 100 as a sectional view from two different perspectives, which differs from the embodiment in Fig. 1, characterized in that the bore in the transfer section 20 has a branch 68, so that the coolant is passed to a plurality of openings 69 located in the transfer section 20 adjacent to the tool 200. This is important in the use of tools 200, which do not have an internal coolant channel, such. B. drills or cutters. In this case, the coolant can not, as shown in FIG. 1, be passed through a single opening of the coolant line section 60 and further through the tool 200 to the tool tip. In the exemplary embodiment shown in FIG. 2, instead of the branch 68 in several channels 71 (eg in three channels 71 as in FIGS. 2A / B), which can be arranged all around the tool 200, the coolant is supplied to the openings 69 directed. There, the coolant with the aid of a deflecting element 21 is guided on the tool holder 100 to the tool 200 around to the tool tip. The deflecting element 21 can be exchangeably attached to the tool holder 100. In this way, on the one hand the ultrasonic transducer 70 is additionally cooled on the side facing the tool 200 and on the other hand also the outside of the tool is cooled.

The present invention is not limited to the above-described embodiments, but rather, individual aspects of the above-described embodiments may be combined to provide further embodiments of the present invention.

LIST OF REFERENCE SIGNS

100 tool holders 10 housings

20 transmission element

21 deflecting element

30 first end portion

40 fixing section

50 second end portion

60 coolant line section

61 first subsection

62 second subsection

63 first connection section

64 second connecting portion

65 sealing element

66 transition section

67 pipe section

68 branching

69 opening

71 channel

70 ultrasonic transducer

80 stabilizing element

200 tools

300 machine tool

Claims

1. tool holder (100) for receiving a tool (200), with

a housing (10), a transmission element (20) movably arranged in the housing (10) for transmitting movement to a first end section (30) of the housing

Tool holder (100) recorded tool (200), a fixing portion (40) on a second, the first end portion (30) of the tool holder (100) opposite end portion (50) of

Tool holder (100) for securing the tool holder (100) to a

A machine tool (300) and a coolant line section (60) for conducting coolant from the second end section (50) of the tool holder (100) to the first end section (30) of the tool holder (100), characterized in that the coolant line section (60) has a by the transmission element (20) extending first portion (61), wherein the first portion (61) is at least partially formed as a bore in the transmission element (20).

2. Tool holder (100) according to claim 1, wherein

the coolant conduit section (60) has a second subsection (62) extending through the attachment section (40), the first subsection (61) and the second subsection (62) being arranged movable relative to one another.

3. Tool holder (100) according to claim 2, wherein

the first subsection (61) at a second subsection (62) facing the end of a first connecting portion (63) for connection to the second

Part section (62), and the second section (62) at a said first portion (61) facing the end of a second connecting portion (64) for connection to the first

Parting portion (61), wherein the first connecting portion (63) and the second connecting portion (64) are joined together.

4. Tool holder (100) according to claim 3, wherein

the first connecting portion (63) is formed as a hollow pin and is arranged on the first portion (61) of the Kühlmittelleitungsabschnitts (60) that the bore in the transmission element (20) is continued by an inner space of the hollow pin, and the second connecting portion (64) first connecting portion (63) for introducing the coolant from the second portion (62) in the first portion (61) circumferentially surrounds.

5. Tool holder (100) according to one of claims 3 to 4, with

one between the first connecting portion (63) and the second

Connecting portion (64) arranged sealing element (65) for sealing against leakage of coolant from the coolant line section (60).

6. Tool holder (100) according to claim 5, wherein

the sealing element (65) is formed as a ring made of plastic, which is pressed against an outer wall of the first connecting portion (63).

7. Tool holder (100) according to claim 6, wherein

the outer wall of the first connecting portion (63) is ground.

8. Tool holder (100) according to any one of the preceding claims, with

an ultrasonic transducer (70) connected to the transmission element (20) for generating an ultrasonic vibration for the tool (200), wherein the ultrasonic transducer (70), the transmission element (20) and the first

Part (61) of the coolant line section (60) form a oscillatory system in the housing (10), the coolant line section (60) is arranged centrally in the tool holder (100), and the ultrasonic transducer (70) the bore in the transmission element (20) for cooling of the ultrasonic transducer (70) by the coolant in the bore at least

partially surrounds.

9. Tool holder (100) according to any one of the preceding claims, wherein

the bore in the transmission element (20) is designed such that the coolant passes through the transmission element (20) using a flow cross-section of at least 4.9 mm ² and / or with a pressure of at least 60 bar.

10. Tool holder (100) according to any one of the preceding claims, wherein the first portion (61) has a branch (68); and the transfer section (20) has a plurality of openings (69) of the

Coolant line section (60) has such that the coolant is passed from the branch (68) to the openings (69).

11. Tool holder (100) according to claim 10, with a replaceable on the tool holder (100) arranged deflecting element (71) for deflecting the out of the openings (69) exiting coolant in a direction of the tool holder (100) recorded tool (200).

12. Tool holder (100) according to one of the preceding claims, with

a stabilizing member (80) circumferentially disposed about the first connecting portion (63) and the second connecting portion (64) for stabilizing connection of the first portion (61) of the coolant conduit portion (60) and the second portion (62) of the coolant conduit portion (60).

13. Tool holder (100) according to any one of the preceding claims, wherein the coolant is air or water or an emulsion.

14. Machine tool (300), with

The tool holder (100) according to any one of the preceding claims, wherein the tool holder (100) accommodated in the tool holder (100) and parts of the tool holder (100) arranged in the housing (10) of the tool holder (100) along an axial direction of the tool holder (10). 200) are coolable during workpiece machining by the coolant in the coolant line section (60).