CN100579695C - Tool holder and method for clamping a rotary tool in a tool holder - Google Patents

Abstract

A tool holder (1), in particular of the shrink-fit type, is proposed, the clamping part (5) of which comprises a clamping device (9) arranged concentrically to the axis of rotation (7) of the tool holder (1) for fixing a shank (15) of a rotary tool, said clamping device defining a receiving opening (13) for the shank (15), wherein the clamping device (9) is radially movable between a radially enlarged release position for inserting or removing the tool shank (15) and a clamping position, in the clamping position, the clamping device (9) exerts a radial press-fit force on the tool shank (15) which fixes the tool shank (15) in a friction-locked manner on its cylindrical outer circumferential surface (19), and wherein the clamping device (9) is provided with a clamping surface (17) having a cylindrical outer shape, which abuts in surface contact against the outer circumferential surface (19) of the shank (15) in the clamping position. The region of the tool holder (1) forming the clamping surface (17) has a plurality of groove sections (21) which are curved about the axis of rotation and are spaced axially apart from one another and which, viewed in the direction of the axis of rotation (7), define a plurality of bearing regions (25) which are integrated with one another and are arranged at an axial spacing from one another and project toward the axis of rotation (7), the top surfaces (27) of which, facing the axis of rotation (7), form the cylindrical clamping surface (17).

Description

Tool holder and method for clamping a rotating tool in the tool holder

technical field

The invention relates to a tool holder for a rotary tool and a method for clamping a rotary tool in the tool holder.

Background technique

In practice, various tool holders are used for clamping rotating tools, such as drills or milling cutters, whose clamping device fixes the tool holder of the rotating tool with a radial force fit with a slight maximum displacement. Relates to the rule that the smaller the clamping displacement, the higher the precision and concentricity of the tool holder. In this way, precision spring collets have a clamping displacement of only a few millimeters, while other precision collets, such as hydraulic expansion collets or mechanism collets with an annular closed clamping device, especially shrink collet types The tool holder is designed so that rotating tools with a single nominal shank diameter can be clamped directly in the tool holder.

Sufficiently high press-fit forces can be achieved with the tool holder described above. However, it has been found that vibrations of the rotating cutting surface of the tool are excited, which leave chatter marks etc. in the cross-sectional view of the machined workpiece. This limits the achievable feed speed of the machine tool.

It has also been found that rotary tools, which are mounted sufficiently securely in the tool holder during a vibration-free movement, start to move axially in the tool holder when vibrations occur and can loosen from the tool holder during operation.

Contents of the invention

With respect to the first aspect it is an object of the present invention to provide a tool holder which resists axial movement of a rotating tool during operation better than the prior art. With respect to the second aspect it is an object of the invention that it dampens the vibrations excited by the rotating tool better than the prior art.

The invention starts from a tool holder, the clamping part of which includes a clamping device arranged concentrically to the axis of rotation of the tool holder for fixing a tool handle of a rotating tool, which defines a receiving hole for a tool holder, wherein the clamping device is used in a It is radially movable between a radially enlarged disengagement position for inserting or removing the tool holder and a clamping position, in which the clamping device exerts a radial force on the tool holder to hold the tool holder on its cylindrical outer peripheral surface The press-fit force of the upper frictional lock is fixed, and wherein the clamping device is equipped with a clamping surface with a cylindrical shape, which in the clamping position is in surface contact against the outer peripheral surface of the tool holder. As mentioned at the outset, such tool holders are known as precision tool holders, for example of the shrink chuck type.

A development according to the invention consists in that the clamping region of the tool holder has a plurality of axially spaced groove sections bent around the axis of rotation, which are bounded between them as seen in the direction of the axis of rotation. A plurality of one-piece bearing regions arranged at an axial distance from one another and projecting toward the axis of rotation, the top surfaces of the bearing regions facing toward the axis of rotation form cylindrical clamping surfaces.

The top surface of each bearing area conforms to a cylindrical shape and the overall dimensions are such that the torque required for operation can be transmitted by the press-fit force of the clamping means. However, because the bearing regions are axially free due to the groove portions, they are axially elastic to a certain extent compared with the regions forming the bearing surfaces of conventional tool holders and can eliminate and restrain the clamping parts of the tool holder against each other. due to the bending vibration of the tool holder of the rotating tool. The tendency of the tool shank to move out of the receiving hole is significantly reduced.

The groove parts are expediently formed by at least one helical groove curved around the axis of rotation or by a plurality of annular grooves arranged at an axial distance from one another around the axis of rotation. If the annular groove is involved, a rotationally symmetrical bearing region structure results, which is characterized by a particularly high axial securing force. The production of the support region by means of one or more annular helices axially offset from one another can be produced particularly simply in the manner of a thread cutting process. A rotationally symmetrical bearing region structure is also achieved in this case if two opposite helical grooves are cut.

The aforementioned helical or annular grooves produce a strip-shaped bearing region that helically or annularly surrounds the axis of rotation. In one variant, however, it can also be provided that the region of the tool holder forming the clamping surface has a plurality of support regions arranged at a distance from one another on all sides, in the form of all sides separated from one another by groove parts, but integrated into one another. The projection, whose top surface protrudes towards the axis of rotation, again constitutes a cylindrical clamping surface. In contrast to the embodiments described above, the radial or axial elastic properties of the region of the tool holder which forms the clamping surface can be influenced better by means of the projections.

Protrusions of the type described above can be manufactured relatively simply when the bearing areas are delimited along the clamping surface by at least two sets of groove portions, wherein the groove portions of each set extend side by side at intervals in the clamping surface without intersecting, And the groove portions of the different sets intersect within the clamping surface to form bearing areas. For example, the groove parts of the first group may have at least one helical groove bent around the axis of rotation and the groove parts of the second group may have at least one helical groove opposite to the first group or have at least one different helical groove for each group. A helical groove curved around the axis of rotation with the slope of a helical groove is formed or/and by a plurality of annular grooves arranged at an axial distance from each other around the axis of rotation or/and by a plurality of axial extensions distributed along the circumference of the clamping surface The slot composition. Helical grooves, annular grooves or axial grooves can be produced relatively simply by means of machine tools. In one variant, however, it can also be provided that the groove parts of the first group pass through a plurality of annular grooves arranged at an axial distance from one another about the axis of rotation, while the groove parts of the second group pass through at least one helical groove curved about the axis of rotation Formed or/and formed by a plurality of axially extending grooves distributed along the circumferential direction of the clamping surface.

Viewed in an axial longitudinal section of the clamping part, the top surface of the bearing regions together with the groove side surfaces adjoining on the axial sides of the top surface expediently conform to a rectangular shape to form a parallelogram or a trapezoidal shape. At least one groove side surface, in particular both groove side surfaces, of a plurality of adjacent bearing regions expediently extend perpendicularly to the axis of rotation; however, one or both groove side surfaces may also have a conical shape. The vibration-damping behavior of the bearing region structure can be varied by a suitable selection of the inclination angle.

If the two conical groove flanks taper in the same direction in the direction of the axis of rotation, bearing regions are formed which run obliquely with respect to the axis of rotation and which reinforce the forces exerted on the tool shank when the respective groove flank tapers away from the rotating tool. Press fit force for outward movement of the tool holder. Expediently, each of the two groups is provided with a plurality of axially adjacent bearing regions, the side surfaces of the conical grooves of which taper in the same direction, while the side surfaces of the conical grooves of the two groups taper in opposite directions. In this case, axial displacement of the tool shank during bending vibrations of the tool holder is particularly well prevented. This is especially the case when the side surfaces of the conical grooves of the two groups taper towards each other.

The width of at least one helical groove or the width of each annular groove with respect to the width of the top surface between the groove turns of the respective adjacent helical grooves or between the respective adjacent annular grooves influences the utility knife clamped in the tool holder The vibration damping performance and inertia of the handle. Preferably the width of the helical or annular groove is smaller than the width of the top surface of the bearing region remaining in between. The smaller the groove width, the larger the clamping surface remains for transmitting the press-fit force. Conversely, the width of the top surface together with the inclination angle of the side surfaces of the groove influence the vibration-damping properties of the bearing region. It has also been found that the radial depth of at least one helical groove or the depth of each annular groove is expediently greater than the width of the helical groove or the width of the annular grooves in order to ensure sufficient axial elasticity of the bearing region for damping properties.

The groove section formed, for example, by a helical groove, an annular groove or an axial groove can be open towards the receiving opening. In a preferred embodiment, however, the groove parts are filled at least over a part of their longitudinal extension, but in particular substantially over their entire length, with a material different from the material of the region of the tool holder which forms the clamping surface. The filler can be used for different purposes. For example, the packing serves for a liquid-tight seal, in particular in helical or axial grooves. However, the filler can also be sufficient to improve vibration damping or it can also provide thermal insulation for the tool holder during the shrinking process, for example in the case of a shrink chuck type tool holder. The filler may comprise plastic or ceramic or metal.

The individual groove parts, for example formed as helical grooves or annular grooves, can be formed directly into the material of the clamping part of the tool holder. In the case of a shrink collet-type tool holder, they can be formed directly into the heat-expandable housing part which forms the receiving opening for receiving the tool holder. However, it has also proved to be expedient to form the bearing region or the bearing element in a possibly separate radially elastic sleeve which itself engages in the receiving opening of the tool holder and which guides the diameter of the clamping device of the tool holder Transfer force to the press fit tool. Such a sleeve can be used as a diameter compensating sleeve, by means of which a tool holder which is only intended for clamping a single nominal diameter of the tool holder can also be used for other, even smaller tool holder diameters. Especially in the case of a shrink chuck type tool holder, such a sleeve also makes it easier to achieve a maximum clamping displacement. In such an embodiment it is expediently provided that the groove parts, for example formed as helical grooves or annular grooves, are arranged on a cylindrically formed clamping surface of a radially elastic sleeve which receives the tool holder of the rotary tool In the inner circumferential surface of the clamping device, and the clamping device has another clamping surface that defines the receiving hole and can move radially between the disengagement position and the clamping position, wherein in the disengagement position of the clamping device, on the one hand, the sleeve The sleeve can be inserted into or removed from the receiving opening and/and on the other hand the tool holder can be inserted into or removed from the sleeve, while in the clamped position the sleeve transmits the radial press-fit force of the clamping device to the tool holder. The sleeve can be a separate component that can be removed from the tool holder; as will be explained below, the sleeve can also be fixedly connected to the tool holder or integrally formed thereon.

The sleeve preferably has at least one axially extending compensation slot, but preferably a plurality of such compensation slots distributed in the circumferential direction, in order to obtain sufficient radial elastic properties and to weaken the force fit exerted by the clamping device as little as possible force. Axially extending grooves or axial openings passing radially through the sleeve can be present in the compensation gap. In particular, individual grooves can be provided both on the inner circumferential surface and on the outer circumferential surface in order to achieve particularly good radial elastic properties due to the meander-shaped cross-sectional structure formed in this way.

The clamping displacement of precision tool holders, especially tool holders of the shrink chuck type, usually presupposes the maintenance of a tool holder diameter with narrow tolerance limits. In order to be able to utilize the clamping displacement as best as possible even when using a diameter compensating sleeve, it is provided in a preferred embodiment that the sleeve comprises an inner sleeve and an outer sleeve arranged concentrically with one another, wherein the outer sleeve Has a conical inner surface, while the inner sleeve has a conical outer surface that is close to the conical inner surface of the outer sleeve and an inner surface of cylindrical configuration that constitutes the clamping surface of the sleeve, the inner diameter of which can pass through the inner The sleeve and the outer sleeve are shifted axially relative to each other until the clamping surface abuts against the shank. Such a sleeve makes it possible to eliminate the diameter difference between the outer diameter of the tool shank and the nominal inner diameter of the tool holder and to compensate for the diameter tolerances of the tool shank. For this purpose, the two-part sleeve is first pushed onto the tool shaft and is fixed on the tool shaft with a certain clamping fit by moving the inner sleeve relative to the outer sleeve. However, this clamping force does not yet have to be of the magnitude required to transmit the operating torque, since for this purpose the clamping device of the tool holder then exerts the necessary press-fit force on the tool shank via the sleeve. In the case of a two-part sleeve, it is also possible to provide compensation slots in the form of axially extending grooves or openings at least on the inner sleeve, preferably also on the outer sleeve, in order to improve the radial elastic properties.

The outer circumferential surface of the sleeve may have a cylindrical shape. However, in order to be able to position the sleeve axially firmly in the tool holder, which is particularly important in the case of shrink chuck-type tool holders that are also subject to axial thermal expansion, it can be provided according to a preferred embodiment that the The other clamping surface of the above-mentioned clamping device is formed as a conical inner surface and the sleeve has a conical outer surface adjoining the conical inner surface, which corresponds to the direction of the conical inner surface towards the rotation axis towards the rotary tool. The direction is gradually reduced. On the side of the region of its clamping surface axially remote from the rotary tool, the sleeve is axially supported on the tool holder. During the transition from the disengaged position to the clamped position, the clamping device automatically pulls the sleeve axially against a bearing surface, for example of a tool holder, which is formed as an axial shoulder.

In the case of a tool holder of the shrink chuck type, in order to form the clamping device, the tool holder can have a tool holder which can be turned into the disengaging position by heating and into the clamping position by cooling, forming another clamping surface. A housing part with a conical inner surface which surrounds the outer conical surface of the sleeve and is fixedly connected to the tool holder on the side of the clamping surface formed by the inner peripheral surface of the sleeve which is axially remote from the rotary tool. Such a housing part generates not only a radial press-fit force but also an axial force during cooling, which on the one hand acts on the sleeve radially in the manner of a collet and on the other hand presses the sleeve axially against it. bearing surface. With the aid of such a tool holder, high press-fit forces and simultaneous precise positioning can be achieved.

Of particular importance are those embodiments in which the housing part has, on the side axially remote from the rotary tool, an extension extending axially out of the region forming the other clamping surface and surrounding the tool holder and/or the sleeve at a radial distance. part, and the end part of the extension part is fixedly connected to the tool holder. At the transition from the disengaged position to the clamped position, the axially constricted sleeve part shortens and generates a permanently acting axial clamping force on the sleeve, which damps vibrations occurring during operation, in particular bending vibrations. The vibration-damping action relates in particular to a combination of friction-locking and positive-locking clamping of the sleeve part on the conical outer circumference of the sleeve.

Also particularly advantageous is a development in which the housing part consists of a material whose coefficient of thermal expansion is greater than the coefficient of thermal expansion of the sleeve and/or of the region of the tool holder which is surrounded by the housing part. The increased thermal expansion capacity of the sleeve part on the one hand increases the clamping displacement of the tool holder and on the other hand increases the axial clamping force required for vibration damping in the clamped position.

To turn the tool holder into the disengaged position, the housing part can be heated only in the region of the sleeve; however, it can also be heated along its entire length in order to increase the opening displacement. It has proven to be advantageous if the sleeve is fixedly connected to the tool holder at its end facing away from the rotary tool and the housing part is heated essentially only in its extension for turning into the disengaged position. Conventional tool holders of the shrink chuck type are usually heated, for example inductively, in the region of the clamping surface of the clamped tool shank. For this purpose it must be ensured that only the housing part is heated, but not the tool shaft at the same time, otherwise it would be difficult to remove the tool. Conversely, if the housing part is heated only in the region of the extension and thus axially outward of the clamping surface of the fastening tool shank, no clamping effect which is difficult to remove occurs.

A tool holder of the shrink chuck type of the above-mentioned type, in which the tool shank is clamped by press-fit force by a housing part of a tool holder via a sleeve or a sleeve part with a conical outer surface, also has independent inventive importance , regardless of whether the cylindrical clamping surface of the sleeve or the sleeve portion abutting against the tool shank is divided into support elements or support regions by a helical groove or annular grooves. It is important first of all that the housing part surrounds a sleeve part centered on the axis of rotation, axially supported on the tool holder, radially elastic, which constitutes the receiving hole of the shank of the rotary tool, the inner peripheral surface of which forms a clamp Tight surface so that the press-fitting force of the shell part is transmitted to the handle and the shell part has a conical inner surface, while the sleeve part has a conical outer surface which tapers toward the rotary tool in the direction of the axis of rotation, Wherein the conical inner surface abuts against the conical outer surface in the clamping position. The housing part here has, on the side axially remote from the rotary tool, an extension extending axially beyond the region of the clamping surface of the sleeve part, surrounding the tool holder or/and the sleeve part at a radial distance, said extension The end area of the part is fixedly connected to the tool holder. Alternatively or additionally, it can be provided that the housing part is formed from a material whose coefficient of thermal expansion is greater than the coefficient of thermal expansion of the sleeve part and/or of the region of the tool holder which is surrounded by the housing part. In this tool holder, as mentioned above, preferably only the region of the extension of the housing part is also heated in order to remove the tool holder.

Description of drawings

Exemplary embodiments of the invention are explained in more detail below with reference to the drawings. in:

The tool holder of Fig. 1-shrink chuck type comprises the axial longitudinal sectional view of a supporting element structure of the present invention;

Fig. 2 is the axial longitudinal sectional view of the first scheme of the fixture including the supporting element structure;

Fig. 3 is the axial longitudinal sectional view of the second scheme of the fixture including the supporting element structure;

Fig. 4 tool fixture comprises an axial longitudinal sectional view of a sleeve forming the supporting element structure;

Figure 5 is an axial view of the sleeve of the tool holder in Figure 4;

Fig. 6 is an axial longitudinal sectional view of a scheme of the clamp comprising a sleeve comprising a supporting element structure;

An axial longitudinal sectional view of a solution of the tool holder in Fig. 7 Fig. 6;

An axial longitudinal sectional view of a solution of the tool holder in Fig. 8 Fig. 7;

FIG. 9 is an axial view of a sleeve included in the tool holder according to FIG. 8;

Fig. 10 is an axial longitudinal sectional view of a shrink chuck type tool holder including a diameter compensating sleeve;

Fig. 11 is an axial longitudinal sectional view of a third option of a tool holder including a supporting element structure;

Fig. 12 is an axial longitudinal sectional view taken along line XII-XII in Fig. 13 of a scheme of a tool holder comprising the support element structure of Fig. 11;

Figure 13 Axial view of the tool holder in Figure 12;

Fig. 14 is an axial longitudinal sectional view of a fourth solution of a tool holder including a supporting element structure;

FIG. 15 is an axial longitudinal sectional view of a variant of the structure of a tool holder including the support element in FIG. 14 .

Detailed ways

Figure 1 shows a tool holder 1 of the shrink chuck type, which comprises an engagement part 3, here in the form of a hollow shank taper (HSK), for rotational fixation with a working spindle of a machine tool at one of its axial ends ground engagement; and a clamping portion 5 at the other axial end thereof. The axis of rotation of the tool holder 1 is indicated with 7 . The engagement portion 3 can have any shape, ie also in the form of a steep taper or the like. The clamping part 5 has the basic shape of a housing 9 , which terminates in an end face 11 extending perpendicular to the axis of rotation 7 and comprises a cylindrical receiving opening 13 concentric to the axis of rotation 7 , a rotary tool not shown in detail, A cylindrical tool shank 15 , for example a milling cutter or a drilling tool, is inserted exchangeably into the receiving bore as will be described in more detail later. For the sake of clarity, FIG. 1 shows the tool shank 15 prior to insertion into the receiving hole 13 , which is held in the receiving hole 13 in a force-fit and frictionally locked manner by the radial inner peripheral surface of the housing 9 , which forms a clamping surface 17 . .

The outer diameter of the outer circumferential surface of the tool shank 15 is slightly larger than the inner diameter of the clamping surface 17 . When the clamping part 5 is heated, for example by means of an inductive shrinking device of the type described in WO 01/897 58 A1, the receiving hole 13 expands so that the tool shank 15 can be inserted into the thermally expanded receiving hole 13. After cooling, the housing 9 of the clamping part 5 exerts radial pressure on the tool shank 15 and fixes it in the clamping part 5 . In order to be able to remove the tool shank 15 from the tool holder 1 again, the clamping part 5 is reheated until it is released from the tool shank 15.

During operation of the rotary tool clamped in the tool holder 1 , vibrations, in particular bending vibrations, can occur. In order to prevent the tool shank 15 from moving axially out of the receiving hole 13 due to vibrations, the housing 9 includes groove parts in the form of a plurality of annular grooves 21 in the region of the clamping surface 17, which are formed side by side at an axial distance on the clamping surface of the housing 9. 17 in. The annular grooves 21 have mutually parallel side surfaces 23 perpendicular to the axis, which delimit between adjacent annular grooves 21 support elements 25 in the form of individual annular ribs. Each support element 25 has a top surface 27 constituting a plurality of clamping surfaces 17 .

Since axially adjacent bearing elements 25 are each separated from one another by an annular groove 21 , they are axially elastic to a certain extent and can compensate for axial expansion differences between tool shank 15 and housing 9 . A suitable selection of the radial depth of the annular groove 21 relative to the axial width of the support element 25 on the one hand and, on the other hand, an appropriate selection of the axial width of the annular groove 21 in relation to the axial width of the support element 25 can influence the stability of the tool holder 1 . The vibration behavior of the clamping region 5 and thus influences its damping properties. Expediently, the radial depth of the annular groove 21 is greater than the axial width of the top surface 27 and preferably also greater than the axial width of the annular groove 21 in order not to weaken the clamping surface 17 too much on the one hand and to secure the support element on the other hand. 25 sufficient axial elasticity. Preferably the width of the annular grooves 21 is also smaller than the width of the top surface 27 between adjacent annular grooves 21 in order to ensure a sufficiently large clamping surface 17 .

In the exemplary embodiment of FIG. 1 , the clamping surface 17 is defined by a plurality of annular top surfaces 27 arranged axially side by side. Instead of a plurality of annular grooves 21 arranged axially next to each other, it is also possible to provide a single helical groove or optionally a plurality of axially offset helical grooves which are arranged helically in the clamping surface 17 . Such a helical groove, not shown in greater detail, produces the respective ring support element, which corresponds to the aforementioned annular support element 21 .

The various schemes of the tool holder in FIG. 1 are described below, and the parts that play the same role are indicated by the symbols of the above-mentioned embodiments and provided with a letter to show the difference. The entire description is referred to in order to illustrate the structure and the principle of action as well as possible solutions.

In the exemplary embodiment of FIG. 1 , both groove side surfaces 23 of the annular groove 21 extend perpendicularly to the axis of rotation 7 , and thus the bearing elements 25 have a rectangular shape, viewed in axial longitudinal section of the clamping part 5 . In one variant, the groove side surfaces are also inclined to the axis of rotation 7 by an acute angle different from 90°, so that they have an essentially conical shape. According to the direction in which the conical groove side surfaces of each annular groove or each helical groove taper in pairs relative to each other, the top surfaces of the bearing regions—viewed in axial longitudinal section of the clamping portion 5—also conform to a parallelogram shape or a trapezoidal shape.

FIG. 2 shows a tool holder 1a, the clamping part 5 of which is formed by a housing 9a which forms a receiving opening 13a for a tool shaft (not shown in detail). The inner peripheral surface of the receiving hole 13a of the housing 9a, which is used again as the clamping surface 17a, comprises a plurality of annular grooves 21a arranged axially side by side, the groove side surfaces 23a of which extend conically and pass away from each other in the direction of the axis of rotation 7a. The insertion side of the tool shank defined by the end face 11 a tapers in the same direction and at the same cone angle. The bearing elements 25 a remaining between adjacent annular grooves 21 a thus generally have the shape of a parallelogram and are positioned obliquely opposite to the pulling-out direction of the tool shank. When the tool shank is loaded in the pull-out direction, the bearing elements 25a are erected, which increases the radial contact force exerted on the tool shank.

Figure 3 shows a tool holder 16 which differs from the tool holder of Figure 2 substantially in that the bearing surface 17b of the housing 96 comprises two sets of annular grooves 21b and 21b' which have conical groove side surfaces 23b or 23b' respectively , which are respectively formed in pairs between the obliquely positioned support elements 25b or 25b'. The groove side surfaces 23b or 23b' taper in the same direction in each group and have the same taper angle, but the groove side surfaces of the two groups taper in opposite directions. The respective support elements 25b or 25b' of the two groups formed by the respective annular grooves 21b and 21b' are thus positioned obliquely in opposite directions. In the illustrated embodiment, the individual annular grooves 21b and 21b' of the two groups taper towards each other. Both groups comprise approximately the same number of support elements.

In the variants of the tool holder described above, the support element structure is formed directly in the material forming the housing of the clamping part 5 integrally formed on the tool holder. FIG. 4 shows a variant of a shrink collet-type tool holder 1c whose housing 9c, which forms the clamping part 5c, forms a cylindrical receiving opening 29 for a sleeve 31 concentrically to the axis of rotation. The sleeve 31 has a cylindrical outer peripheral surface 33 and forms with its likewise cylindrical inner peripheral surface the clamping surface 17c of the tool holder for press-fitting the clamping tool shank 15c.

As shown in FIG. 5, the clamping surface 17c of the sleeve 31 includes a plurality of axially extending grooves 35 distributed in the circumferential direction. Further axially extending grooves 37 in the outer circumferential surface 33 of the sleeve 31 are respectively arranged centrally between a pair of grooves 35 . The sleeve 31 thus has an approximately meandering wall structure in axial cross-section and thus has radial elastic properties. Of course, the openings 35 and 37 can optionally also be formed as openings radially through the sleeve 31 .

In contrast to the embodiment of FIGS. 1 to 3 , the annular grooves 21 c and the annular bearing elements 25 c formed between the annular grooves 21 c are formed in the bearing surface 17 c formed by the sleeve 31 . In the illustrated embodiment the annular grooves 21c have groove side surfaces 23c extending perpendicularly to the axis. However, it is also possible to modify the groove side surfaces 23 c according to the variants explained with reference to FIGS. 1 to 3 or below with reference to FIGS. 11 to 15 .

The tool holder 1c is expanded to its disengaged position by heating the housing 9c. In this position, the radially elastic sleeve 31 is enlarged radially so that the tool shaft 15c can be inserted into or removed from the receiving opening 13c. After cooling, the housing 9c is press-fitted to clamp the tool shank 15c, at which time the press-fit force is transmitted from the housing 9c to the tool shank by the sleeve 31 which is pressed against the cylindrical outer peripheral surface 19c of the tool shank 15c in surface contact with the clamping surface 17c. 15c.

The sleeve 31 is removably installed in the housing 9c, so that the tool holder 1c can be matched with tool holders of different diameters by replacing the sleeve 31 . Expediently, the inner peripheral surface 29 of the housing 9c is delimited on the side axially remote from the end face 11c by an annular shoulder 39 on which the sleeve 31 is axially supported and positioned with its inner end.

Fig. 6 shows a tool holder 1d, which differs from the tool holder 1c substantially only in that the outer peripheral surface 33d of the sleeve 31d and the inner peripheral surface 29d of the housing 9d which is close to the outer peripheral surface 31d have a conical shape and are directed toward the housing. The tool-side end surface 11d of 9d tapers gradually. The radially elastic sleeve 31d is then automatically drawn towards the shoulder 39d and axially positioned there when the tool holder 1d is clamped.

FIG. 7 shows a tool holder 1 e which differs from the tool holder of FIG. 6 substantially in that the conical inner peripheral surface 29 e of its conical outer peripheral surface 33 e abuts against the same conical outer peripheral surface 33 e of the sleeve 31 e, which is produced in the clamping position. On its side axially remote from its end face 11e and thus from the rotary tool, the press-fit housing 9e has a likewise sleeve-shaped extension 41 formed at a radial distance on the side axially remote from the sleeve 31e An annular gap 43 surrounds the area of the tool holder 1e which forms the shoulder 39e. The extension part 41 is fixedly connected to the tool holder 1e at its end axially away from the end surface 11e. The sleeve 31e can be removably inserted into the housing 9e; however, it can also be fixedly connected to the tool holder 1e in the region of the shoulder 39e, for example welded or integrally formed on the tool holder 1e. The housing 9 e is expediently produced as a separate component and is subsequently fixedly connected, for example welded, to the tool holder 1 e at the end of the extension 41 axially remote from the rotary tool, as indicated at 45 .

The tool holder 1e is of the shrink chuck type. To disengage the tool holder 1 e , the housing 9 e is heated, for example inductively, at least in its region around the conical inner peripheral surface 29 e of the sleeve 31 e , as indicated by the arrows 47 . The heating can also extend toward the area of the extension 41 (arrows 49), which has the advantage that the housing 9e, which clamps the tool shank 15e via the sleeve 31e, expands not only radially but also axially, which increases the size of the tool holder. Open displacement of 1e.

When cooling, the housing 9e not only contracts radially to generate a radial press-fit force exerted on the tool shank 15e, but also contracts in the axial direction. The axial contraction via the conical surfaces 29e, 33e on the one hand increases the radial press-fit force but on the other hand axially tensions the housing 9e. It has been found that the axial tensioning of the housing 9e reduces vibrations of the tool holder during operation. Since the conical inner peripheral surface 29e frictionally surrounds the outer peripheral surface 33e of the sleeve 31e, the frictional losses occurring there increase the damping effect.

The housing 9e may be constructed of the same material as the remainder of the tool holder 1e and the sleeve 31e. Preferably, however, the housing 9e consists of a material whose coefficient of thermal expansion is greater than the coefficient of thermal expansion of the sleeve 31e and at least the region of the tool holder 1e which forms the stop surface 39e. In this way, the clamping displacement of the tool holder 1e and also the maximum achievable axial clamping force of the housing 9e can be increased and thus the vibration damping effect can be improved.

In the exemplary embodiment of FIG. 7 , the sleeve 31 e is provided with the bearing element structure described above with reference to FIGS. 1 to 3 or explained below with reference to FIGS. 11 to 15 . Of course, the bearing surface 17e of the sleeve 31e can optionally also be constructed without such bearing elements.

FIG. 8 shows a tool holder 1f of the shrink chuck type, which differs substantially from the tool holder 1f of FIG. The sleeve 31f of the inner peripheral surface 29f is fixedly connected to the tool holder 1f by welding at a weld seam 51 and is provided with axially longitudinally extending openings 53 radially through the sleeve 31f in order to achieve its radial elastic properties. Of course, the sleeve 31f can also be integrally formed on the tool holder 1f. The housing 9f again has an extension 41f surrounding the tool holder 1f at a radial distance on the side of the bearing surface 17f axially away from the rotating tool and is fixedly connected to the tool holder 1f on the side of the extension 41f axially away from the rotating tool, wherein A weld at 45f is welded. The housing 9f is preferably formed from a material which has a higher coefficient of thermal expansion than the material of the sleeve 31f and the tool holder 1f in the region of the extension 41f.

Expediently, the tool holder 1f is heated only in the region of the extension 41f, as indicated by the respective arrows 55 in FIG. 8 . The region of the housing 9f surrounding the sleeve 31f is not heated together, so that only a radial press-fit force acting on the sleeve 31f is produced by the relative axial displacement of the conical surfaces 29f, 43f in the manner of a spring clip. When the tool holder 1f is clamped, an axial clamping force is generated in the housing 9f which, as described above in connection with FIG. 7 , improves the vibration-damping properties of the tool holder.

FIG. 10 shows a shrink chuck type tool holder 1g which, like the tool holder 1c of FIG. 4, includes a diameter compensation sleeve 31g in the conical inner peripheral surface 29g of its housing 9g. The inner peripheral surface of the diameter compensation sleeve 31g forms a clamping surface 17g which, in the clamped state of the tool holder 1g, press-fits against the outer peripheral surface 19g of the tool shank 15g inserted into the receiving hole 13g .

Different from the sleeve 31 of the tool holder 1c in FIG. 4, the sleeve 31g includes an outer sleeve 57 and an inner sleeve 59 arranged concentrically with each other, wherein the outer sleeve 57 constitutes a cylindrical outer peripheral surface 33g and has a conical inner surface. The inner sleeve 59 forms the clamping surface 17g and has a conical outer surface 63 which abuts against the conical inner surface of the outer sleeve 57 . The inner sleeve 59 is designed to be radially elastic and has individual grooves distributed in the circumferential direction on its inner clamping surface 17 g and/or axially extending on its outer circumferential surface 63 , for example similarly to the sleeve 31 in FIG. 5 . Correspondingly, the outer sleeve 57 is designed to be radially elastic. Instead of grooves, radial through openings can also be provided, as shown for the openings for sleeve 31g in FIG. 9 . The inner diameter of the clamping surface 17g can be changed and variably adapted to the diameter of the tool shank 15g by means of an axial relative displacement of the outer sleeve 57 and the inner sleeve 59 . In this way, tool shanks of different diameters can be clamped within a certain diameter range with one and the same sleeve 31g.

To clamp the tool shank 15g, the sleeve 31g, which is removed from the housing 9g of the tool holder 1g, is placed on the tool shank 15g. The clamping surface 17g can then be brought into close-fitting ground contact against the tool shank 15g by axial movement of the outer sleeve 57 and the inner sleeve 59 relative to each other. In order to facilitate abutment, the narrowing end of the inner sleeve 59 is provided with an external thread 65, which can be screwed into the internal thread 67 of the outer sleeve. It is sufficient to eliminate only the play between the clamping surface 17g and the tool shank 15g, since the press-fit force required for operation is exerted by the housing 9g via the sleeve 31g on the tool shank 15g. In order that the sleeve can be inserted axially securely into the housing 9g, the outer sleeve 57 is provided with an annular collar 69 which abuts against the end face 11g of the housing 9g.

In the region of its clamping surface 17g, the inner sleeve 59 is provided with a structure of an annular support element 25g formed by annular grooves 21g, as explained in detail with reference to FIGS. 1 to 5 .

Further variants of the carrier element structure already described with reference to FIGS. 1 to 3 are described below with reference to FIGS. 11 to 15 . The carrier element structure can be used not only in the tool holder of FIG. 1 but also in FIGS. 4 to 10 described below.

In the support element structure described above, the groove part, which is formed as a helical groove or an annular groove, produces a respective helical groove-shaped or annular closed, strip-shaped support element extending longitudinally around the axis of rotation. FIG. 11 shows a tool holder 1h whose clamping part 5h is formed by a housing 9h which forms a receiving opening 13h for a tool shaft not shown in detail. The inner peripheral surface of the accommodation hole 13h of the housing 9h serving again as the clamping surface 17h includes a plurality of helical groove portions 21h arranged axially side by side, each groove side surface 23h of which extends radially at right angles.

Two sets of helical groove sections 21h' and 21h" are provided, in the first of the two sets the individual helical groove sections 21h' have the same inclination and extend side by side with an axial distance from each other, ie do not intersect. Correspondingly The same is true for the helical groove portions 21h″ of the second group, but wherein the inclinations of the helical groove portions 21h″ of the second group are the same but opposite to the inclinations of the helical groove portions 21h′ of the first group. Therefore each The helical groove portions 21h'' intersect the respective helical groove portions 21h' and in this way form a plurality of support elements 25h in the form of rhombic projections spaced all around from each other. If the two helical groove portions 21h' and 21h" are wound in the same direction but have different inclinations from each other, many similar protrusions are formed.

12 and 13 show a variant 1i with a first set of annular grooves 21i perpendicular to the axis axially offset from each other, as explained with reference to FIG. 1 and also with a second set of circumferential grooves along the clamping surface 17i The respective grooves 69 extending in the direction of the axis of rotation 7i, which are mutually offset in direction, intersect the respective annular groove 21i. A first set of mutually parallel annular grooves 21i and a second set of likewise mutually parallel axial grooves 69 delimit in the clamping surface 17i a plurality of support elements 25i in the form of projections, again spaced apart from each other all around, the tops of which The surface 27i constitutes the support surface 17i similarly to the solution of FIG. 11 .

FIG. 14 shows a tool holder 1k which differs substantially from the tool holder 1a of FIG. 2 only in that each annular groove 21k has, on its side facing the tool insertion side, a groove side surface extending perpendicularly to the axis of rotation 7k. 23k and on its axially opposite side have a conical groove side surface 23k' that tapers axially away from the tool insertion side. The bearing elements 25k thus remaining between adjacent annular grooves 21k generally have a trapezoidal shape and are positioned obliquely opposite the pulling-out direction of the tool shank.

FIG. 15 shows a variant of the tool holder 1k from FIG. 14, which differs substantially from it only in that the annular grooves 21m are filled with a material filling 71 of a material different from the housing 9m. The filler 71 can consist of ceramic, metal or plastic and, depending on the type of material, improves vibration damping and/or ensures thermal insulation of the tool shaft during shrinkage. Of course, vibration-damping or heat-insulating fillers can also be used in the same way in the construction of the support elements in the above-described embodiments of FIGS. 1 to 13 . In individual cases it may be sufficient to provide only a part of the total number of groove parts with such a filler or to fill only a part of the longitudinal extent of these groove parts. In particular in the case of axially extending grooves or helical grooves, sealing of the groove channel can also be achieved thereby.

Claims (33)

1. tool holder comprises:

Clamping part (5), it is in order to the fixing handle of a knife of throw (15) of the rotation (7) that is concentric with tool holder (1);

Clamping device (9), its rotation (7) that is concentric with tool holder (1) are provided with and limit an accommodation hole (13) that is used for handle of a knife (15),

Wherein clamping device (9) is used for inserting or take out between the radially enlarged disengaged position of handle of a knife (15) and the clamped position and can moves radially one, at clamped position clamping device (9) the columniform external peripheral surface (19) of handle of a knife (15) is applied being press-fitted with joint efforts handle of a knife (15) friction is fixed sealedly radially

And wherein be clamping device (9) configuration one clamping surface (17) with cylindrical outer shape, this clamping surface is close to the external peripheral surface (19) of handle of a knife (15) contiguously at the clamped position face;

It is characterized in that, the form of clamping device (9) is one can radially enlarged closing sleeve, and the zone of the formation clamping surface (17) of tool holder (1) has a plurality of around the crooked slot part that keeps axial spacing each other (21) of rotation (7), direction along rotation (7) is seen, described slot part is limited to a plurality of support regions (25) between them, described support region keeps the axial spacing setting each other and protrudes to rotation (7) over there

And described support region (25) their radial outer end portion mutually combine be integral and described support region constitute columniform clamping surface (17) towards rotation (7) top surface (27) over there.

2. according to the described tool holder of claim 1, it is characterized in that each slot part (21) constitutes around the helicla flute of rotation (7) bending or by a plurality of cannelures around rotation (7) that keep axial spacing to be provided with each other by at least one.

3. according to the described tool holder of claim 1, it is characterized in that, tool holder (1h, i) formation clamping surface (17h, i) zone has a plurality of along clamping surface (17h, i) observe the support region (25h that keeps spacing to be provided with in all directions each other, i), its form is for passing through each slot part (21h, i) that separate in all directions each other but projection that mutually combine and be integral in their radial outer end portion, described projection to rotation (7h, i) top surface that over there protrudes constitute cylindrical clamping surface (17h, i).

4. according to the described tool holder of claim 3, it is characterized in that, and each support region (25h, i) (17h is i) by at least two group slot part (21h along clamping surface; 21i, 69) qualification, wherein each slot part (21h of each group; 21i, 69) the spaced apart extension abreast and non-intersect in clamping surface, and each slot part of different groups (21h; 21i, 69) clamping surface (17h, intersect in i) in case constitute each support region (25h, i).

5. according to tool holder claimed in claim 4; It is characterized in that, each slot part (21h ') of first group by at least one around the helicla flute of rotation bending and each slot part of second group (21h ") is in reverse to described at least one helicla flute of first group by at least one or has consisting of and/or keep each other cannelure that axial spacing arranges or/and the axially extended groove formation that a plurality of circumferencial direction along clamping surface distributes and arranges by a plurality of around rotations (7h) around the crooked helicla flute of rotation (7h) of described at least one spiral fluted gradient of being different from first group.

6. according to the described tool holder of claim 4, it is characterized in that, each slot part of first group keeps the cannelures (21i) of axial spacing setting by many each other around rotation (7i), and each slot part of second group constitutes by at least one helicla flute around the rotation bending or/and constitute by many axially extended grooves (69) that are provided with along the circumferencial directions distribution of clamping surface.

7. according to the described tool holder of claim 1, it is characterized in that, axial longitudinal section towards clamping part (5) sees, the top surface (27) of each support region (25) is complied with a rectangular profile or a parallelogram profile or a trapezoidal shape with each the groove side surface (23) in the axial sides adjacency of top surface (27).

8. according to the described tool holder of claim 7, it is characterized in that at least one groove side surface (23) of the support region of many axial vicinities (25) extends perpendicular to rotation (7).

9. according to the described tool holder of claim 7, it is characterized in that (25a, (23a b) has cone shape at least one groove side surface b) to the support region of a plurality of axial vicinities.

10. according to the described tool holder of claim 9, it is characterized in that the support region (25a of described a plurality of axial vicinities, b) each support region (25a, b) two conical tank side surfaces (23a, b) (7a, dwindle gradually in the same way to rotation by direction b).

11., it is characterized in that (25a, (25a, (23a b) dwindles to the side away from instrument two conical tank side surfaces b) each support region b) support region of described a plurality of axial vicinities gradually according to the described tool holder of claim 10.

12. according to the described tool holder of claim 10, it is characterized in that, two groups of support region (25b that respectively are provided with a plurality of axial vicinities, 25b '), its conical tank side surface (23b, 23b ') dwindle gradually in the same way, wherein conical tank side surface (23b, 23b ') oppositely dwindles in two groups gradually.

13., it is characterized in that two groups conical tank side surface (23b, 23b ') dwindles mutually in opposite directions gradually according to the described tool holder of claim 12.

14., it is characterized in that the width of each slot part (21) is less than the width of the top surface (27) between the contiguous slot part (21) according to the described tool holder of claim 1.

15. require 1 described tool holder, it is characterized in that the radial depth of each slot part (21) is greater than the width of slot part (21) and/or the width of top surface (27) according to aforesaid right.

16. according to the described tool holder of claim 1, it is characterized in that, each slot part (21m) on the part of its longitudinal extension length, fill up at least one with the different material (71) of material in the zone of the formation clamping surface (17m) of tool holder (1m).

17., it is characterized in that filler (71) comprises plastics or pottery or metal according to the described tool holder of claim 16.

18. according to the described tool holder of claim 1, it is characterized in that, each slot part (21) is arranged in the inner circumferential surface of the columniform clamping surface of formation (17) of sleeve (31) of the handle of a knife that holds throw (15) of a radial elastic, and clamping device (9) has another clamping surface (29) that can move radially between disengaged position and clamped position, wherein the disengaged position of clamping device sleeve (31) can be embedded in the accommodation hole on the one hand or from wherein taking out or/and handle of a knife (15) can be embedded on the other hand the sleeve or from wherein taking out, and radially being press-fitted of clamping device (9) made a concerted effort to pass to handle of a knife (15) at clamped position sleeve (31).

19., it is characterized in that sleeve (31) has at least one axially extended compensation slit (35,37) according to the described tool holder of claim 18.

20., it is characterized in that described at least one compensation slit constitutes axially extended groove (35,37) or constitutes the axially extended opening (53) that radially passes sleeve (31) according to the described tool holder of claim 19.

21. according to the described tool holder of claim 20, it is characterized in that, sleeve (31) has a plurality of axially extended groove (35) that along the circumferential direction cuts out and the axially extended groove (37) that has other on its external peripheral surface (33) on the circumferential surface (17c) within it, and described other groove along the circumferential direction is arranged between each a pair of groove (35) of inner circumferential surface (17c).

22. according to the described tool holder of claim 18, it is characterized in that, sleeve (31) comprises the outer sleeve (57) and inner sleeve (59) that is provided with one heart mutually, wherein outer sleeve (57) has a conical inner surface (61), and inner sleeve (59) has the inner surface of cylindrical structure that the conical external surface (63) of being close to conical inner surface (61) and constitutes the clamping surface (17g) of sleeve (31g), and its internal diameter can change till clamping surface (17g) abuts on the handle of a knife (15g) by moving to axial mutually of inner sleeve (59) and outer sleeve (57).

23., it is characterized in that inner sleeve (59) has at least one axially extended compensation slit at least according to the described tool holder of claim 22.

24., it is characterized in that described at least one compensation slit constitutes axially extended groove or constitutes the axially extended opening that radially passes outer sleeve (57) and inner sleeve (59) according to the described tool holder of claim 23.

25. according to the described tool holder of claim 24, it is characterized in that, at least inner sleeve (59) has a plurality of axially extended groove that along the circumferential direction distributes within it on the circumferential surface (17g) and have other axially extended groove on its external peripheral surface (63), and it along the circumferential direction is arranged between each a pair of groove of inner circumferential surface (17g).

26. according to the described tool holder of claim 18, it is characterized in that, clamping device (9c, d, disengaged position e) can from accommodation hole, take out sleeve (31,31d, e).

27., it is characterized in that clamping device (9d according to the described tool holder of claim 18, e, another clamping surface f) constitutes conical inner surface (29d, e, f) and sleeve (31d, e f) have the conical inner surface of being close to (29d, e, conical external surface f) (33d, e, f), it is corresponding to conical inner surface (29d, e is f) at rotation (7d, e, f) dwindle gradually to throw direction over there on the direction, and sleeve (31d, e is f) at its clamping surface (17d, e, the axial side axial away from throw in zone f) is bearing on the tool holder.

28. according to the described tool holder of claim 27, it is characterized in that, in order to constitute clamping device, tool holder (1d, e f) has one can change disengaged position over to and can change clamped position over to by cooling by heating, constitute circular cone inner surface (29d, the e of other clamping surface, f) housing parts (9d, e, f), described housing parts is around sleeve (31d, e, conical external surface f) (33d, e is f) and by sleeve (31d, e, f) (17d, e are fixedly connected on tool holder (1d on the axial side away from throw f) to the clamping surface that inner circumferential surface constitutes, e, f).

29. according to the described tool holder of claim 28, it is characterized in that, housing parts (9e, f) on axial side, have one and axially stretch out the clamping surface (29e that constitutes other away from throw, f) zone, center on tool holder (1e with radial spacing, f) or/and sleeve (31e, extension f) (41,41f), the end regions of described extension is fixedly connected on tool holder (1e, f), or/and housing parts (9e f) is made of a kind of material, its thermal coefficient of expansion is greater than sleeve (31e, f) or/and by housing parts (9e, the tool holder that f) centers on (1e, the thermal coefficient of expansion in zone f).

30. according to the described tool holder of claim 29, it is characterized in that, housing parts (9e, f) be welded on tool holder (1e, f) on.

31., it is characterized in that an axial end away from throw of sleeve (31f) fixedly is welded in tool holder (1f) according to the described tool holder of claim 29.

32. be used for throw is clamped in method according to the described tool holder of claim 29, it is characterized in that, in order to change tool holder over to disengaged position, the heating housing parts (9e, and extension f) (41, zone 41f).

33. according to the described method of claim 32, it is characterized in that, only heat basically housing parts (9e, extension f) (41, zone 41f).

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