CN106607700B

CN106607700B - Tool for machining a workpiece

Info

Publication number: CN106607700B
Application number: CN201510686176.1A
Authority: CN
Inventors: N·登克斯; S·弗特廷格尔; M·海因洛特; J·库尔茨; E·利尔; G·施蓬泽尔
Original assignee: Kennametal Inc
Current assignee: Kennametal Inc
Priority date: 2015-10-21
Filing date: 2015-10-21
Publication date: 2020-09-18
Anticipated expiration: 2035-10-21
Also published as: CN106607700A

Abstract

The invention relates to a tool (2) for machining a workpiece, comprising a carrier (4) which rotates in an axial direction (A) during operation, and further comprising a plurality of cutting segments (6) which are fastened to the carrier (4) in a radial direction (R), characterized in that: at least one hydraulic clamping unit (21) is mounted on the carrier (4) for fixedly clamping at least one of the cutting segments (6) on the carrier (4).

Description

Tool for machining a workpiece

Technical Field

The invention relates to a tool for machining a workpiece, comprising a carrier which rotates during operation about an axial direction and further comprising a plurality of cutting segments which are fastened to the carrier in a radial direction.

Background

Such a tool is known from EP 2136951B 1 and is used, for example, for a lathe-drawn crankshaft when manufacturing a crankshaft. The cutting section of the tool is fastened to the carrier by means of a plurality of bolts. A plurality of cassettes are in turn attached at each cutting section to house the blades. The bolts act radially on the carrier to secure each of the cutting segments to the carrier. Furthermore, the cutting segment may be fixed in the axial direction at the clamping point.

Disclosure of Invention

Object of the Invention

The object of the invention is to improve and in particular to simplify the fastening and replacement of cutting segments on tools.

Solution to the problem

According to the invention, this object is achieved by a tool having the features according to claim 1. Advantageous embodiments, improvements and variants are the subject matter of the dependent claims.

The tool is designed for machining workpieces and is particularly suitable for lathing, for example for producing crankshafts. The tool is in particular a rotary tool and has a carrier which rotates about an axial direction during operation. The carrier thus has an axis of rotation. Furthermore, the tool can be attached to the machine tool by means of a carrier. Furthermore, the tool has a plurality of cutting segments, each of which is fastened to the carrier in a radial direction and surrounds the carrier in a circumferential direction relative to the axial direction. As such, a radial direction is understood to be each direction perpendicular to the axial direction. The cutting segment is formed, for example, in one piece and is provided with suitable cutting edges. Preferably, the cutting segment is designed in multiple pieces, so that a plurality of cutting elements (in particular blades) can be mounted on one cutting segment. To this end, a particular cutting segment has a suitable mounting seat in which a cutting element may be secured. The mounting seat is in this case designed as an insert seat integrated into the carrier or as a separate box which in turn can be fastened to the carrier.

Furthermore, at least one hydraulic clamping unit is mounted on the carrier for fixedly clamping at least one of the cutting segments on the carrier. For this purpose, the hydraulic clamping unit comprises in particular a hydraulic fluid which is used to operate the clamping unit in order to generate a hydraulic pressure. The hydraulic force is in turn converted into a clamping force which serves to clamp the at least one cutting segment in a hydro-mechanical manner fixedly on the carrier.

The advantages achieved with the invention are in particular: a particularly secure and secure locking of the cutting segment can be achieved in a particularly simple manner by means of the hydraulic clamping unit and with only low complexity.

The fastening by clamping is advantageously not carried out individually for each of the cutting segments, but jointly by means of a clamping ring. In a preferred embodiment, the cutting segments can therefore be clamped reversibly on the carrier jointly by means of the clamping ring. This makes handling of the tool significantly simpler than individual clamping of each cutting segment. In this way, a clamping force is exerted by the clamping ring on a plurality of, or in particular all, cutting segments during clamping. Furthermore, the clamping is advantageously reversible, wherein all cutting segments fixed by clamping by the clamping ring can be released simultaneously by means of the clamping ring. Like the carrier, the clamping ring extends in particular in the axial direction of the tool in the circumferential direction. The clamping ring can in particular rotate concentrically in the axial direction relative to the axis of rotation of the carrier.

Expediently, the carrier and the clamping ring are spaced apart from one another in the axial direction and form a clamping groove in which the cutting section sits. During the fixing by clamping, the cutting segment is held rigidly in the clamping groove in the axial direction by the carrier and by the clamping ring. Furthermore, the cutting segment is fixedly clamped in the clamping groove due to the clamping force acting in the axial direction.

In a suitable refinement, the clamping ring can be displaced in the axial direction relative to the carrier by means of a hydraulic clamping unit. In this way, it is advantageously possible to press the respective cutting segment in the axial direction against the carrier, i.e. in order to generate a clamping force in the axial direction, that is to say [ in order to generate ] an axial force and thus fixedly clamp the cutting segment in the axial direction on the carrier. In particular, this will also prevent the cutting segment from slipping in the axial direction during operation. The distance between the clamping ring and the carrier in the axial direction can be set in particular by means of a hydraulic clamping unit. By displacing the clamping ring, the cutting segment can then be fixed or released by clamping.

Each of the cutting segments preferably has a segment base that seats in the clip groove. At least one part selected from the carrier and the clamping ring has a circumferential collar which narrows the clamping groove on a radially outer section and surrounds the segment base. In this way, the forming lock also advantageously takes place in the radial direction and the cutting segment is reliably secured against movement in the radial direction during operation, for example due to centrifugal forces. The clamping groove in particular also forms an annular chamber with an entry slot which is located radially outside and from which the respective cutting segment projects. The respective segment bases of the cutting segments are seated in the clip groove and act on the flange. A circumferential flange is formed at least on the carrier or on the clamping ring. In a preferred variant, the flange is arranged on both the carrier and the clamping ring. In the latter case, the segment base is then surrounded by flanges, in particular on both sides, and is held in a particularly stable manner in the clip groove.

In a cross section which is longitudinal with respect to the axial direction, the sections of the carrier and the sections of the clamping ring which are spaced apart from one another in the axial direction each form an extension or an arm which extends in the radial direction and to which the flange is attached to a respective end which is located externally in the radial direction.

In an advantageous development, the flange has an inclined clamping surface which is directed inwardly with respect to the clip groove and acts on an outwardly directed, inclined shoulder surface of the segment base. Due to this embodiment, an axial movement of the clamping ring during displacement in the axial direction can advantageously be converted into a radial movement of the cutting segment. In this way, the clamping surface and the shoulder surface cooperate, in particular, in the manner of a bevel gear. The clamping force (also referred to as axial force) generated when clamping the clamping ring in the axial direction is at least partially converted into a radial force acting radially inward by means of the inclined arrangement of the clamping surface and the shoulder surface. In this manner, the segment base and corresponding cutting segment are drawn toward the center of the tool. Inclined surfaces are understood here and in the following to mean in particular that the corresponding surfaces are inclined with respect to the axial direction. In particular, the clamping surface of the flange is formed in the shape of a frustoconical sheath. The shoulder surface of the segment base is preferably formed complementary to the clamping surface and in the manner of a segment of a truncated-cone jacket.

For the axial displacement of the clamping ring, a conversion element is expediently arranged on the carrier, which converts the radial displacement generated by the clamping unit into an axial displacement of the clamping ring. The hydraulic clamping unit thus preferably produces an actuating movement of the component in the radial direction (or at least not in the axial direction), which movement is converted by means of the conversion element into the required axial movement of the clamping ring. This enables a compact design, since the carrier of such a tool is usually disc-shaped with only a small extension in the axial direction. The radial extension is typically several times the extension in the axial direction.

In a preferred embodiment, the conversion element is formed as a wedge which can be displaced in the radial direction by means of a hydraulic clamping unit. The clamping wedge has a wedge surface, which acts with the wedge surface on a wedge bearing surface of the clamping ring, in particular during clamping. The wedge surfaces and the wedge support surfaces have an inclined design, so that radial forces acting in the radial direction on the clamping wedge can be converted into axial forces acting in the axial direction, as described above in connection with the flange and the segment base. This force is then used to displace the clamping ring.

When the cutting segment is being clamped, the radial forces acting on the clamping wedge are directed in the radial direction, in particular outwards. In this way, the wedge is acted on by the hydraulic pressure generated by the hydraulic clamping unit. In general, a press rod which is movable in a cavity is arranged in particular in the hydraulic clamping unit. The pressure ram is fixedly connected to the switching element, in particular to the clamping part, and can be moved, that is to say can be displaced, by means of the hydraulic fluid present in the clamping unit. Since the tool generally has a significantly greater extent in the radial direction than in the axial direction, a significantly greater stroke is possible, so that a particularly suitable clamping force can be generated when displacing the clamping wedge in the radial direction.

In order to release the cutting section, the hydraulic force is removed from the conversion element (in particular the clamping wedge) by means of a hydraulic clamping unit, so that the element or wedge can be moved back into the opposite direction. In particular, the transition element (in particular the catch) can be moved inward in the radial direction during the release and is pulled or pressed towards the center of the tool, for example by means of a return spring.

In order to prevent the clamping ring from falling off the tool (in particular in the release position of the clamping element), a pull-out limiter is attached to the tool. The pull-out limiter specifies a maximum axial pull-out of the tensioning disc during the release of the cutting segment. The axial pull-out is in particular selected to be at least large enough to enable the respective cutting segment to be removed from the clamping groove in the radial direction in the release position, when measured in the axial direction. Furthermore, the pull-out stop suitably has an inclined contact surface facing the clamping ring, which is designed in particular like the clamping surface of the clamping wedge and bears against the wedge bearing surface of the clamping ring at the maximum pull-out amount. In order to achieve a particularly effective pull-out protection, the pull-out limiter is expediently designed in the form of a ring.

In order to generate the hydraulic force by means of the hydraulic clamping unit, the tool preferably has a clamping element. The hydraulic clamping unit operates the clamping element to clamp the cutting segment. For this purpose, the clamping element can be switched between a clamping position and a release position in order to fixedly clamp and release the cutting segment. In this way, the pressure pistons in the clamping unit are pressed in by means of the clamping element, so that they initially reduce the cavity filled with hydraulic fluid and in this way drive the pressure pistons out of the cavity.

In a suitable variant, the tool comprises a plurality of hydraulic clamping units which can be actuated jointly by means of the clamping elements, so that in turn the actuation and operation of the tool is considerably simplified. Preferably, at least one hydraulic clamping unit for each cutting segment is mounted on the carrier, and all these hydraulic clamping units can be actuated jointly by means of the clamping elements, so that clamping of all cutting segments can be achieved in a particularly simple manner. Also, clamping is reversible by releasing the clamping element, so that all cutting segments can be released simultaneously.

In a further suitable embodiment, the clamping element is designed as a rotary ring which can be switched by rotation between the clamping position and the release position. The rotating ring is rotatably mounted on the carrier. In particular, it can rotate about the axis of rotation and thus about the axial direction. Rotation to the clamping position then results in clamping of the cutting segment to the carrier, while rotation to the release position correspondingly results in release of the cutting segment. The rotating ring is designed in particular as a circle and extends in the circumferential direction in the axial direction of the tool like a clamping ring. The rotation for switching between the clamping position and the release position accordingly takes place in the axial direction in the circumferential direction. For rotation, the rotary ring is in particular accessible in the axial direction and is operated, for example, manually or by means of a suitable attachment.

For switching between the clamping position and the release position, preferably at least one eccentric actuating element is attached to the clamping element. The actuating element is used to actuate the hydraulic clamping unit when switching into the clamping position. When a plurality of hydraulic clamping units is used, an eccentric operating element is attached to the clamping element, in particular for each of these clamping units. In particular in the case of a clamping element designed as a rotary ring, a translational movement of the eccentric actuating element in the circumferential direction and thus a relative movement with respect to the hydraulic clamping unit takes place during rotation of the rotary ring, so that the clamping unit is actuated in the manner described above. During the rotation of the rotary ring, i.e. during the rotation relative to the hydraulic clamping unit, the eccentric actuating element then acts on the pressure piston of the clamping unit. The eccentric actuating element can also be designed as a projection or recess extending in the radial direction, for example including a bulge. For example, the eccentric operating element is integrally molded to the rotary ring as a wedge-shaped step and is attached to the rotary ring directed outward in the radial direction.

To attach the cutting segments, the cutting segments are initially arranged in a release position, which is distributed around the circumference of the carrier. In particular, in order to achieve a suitable positioning and distribution in the circumferential direction, at least one slotted slider is fastened on the carrier for each of the cutting segments. The slotted slider is, for example, fixedly screwed to the carrier and forms a bearing contour for the corresponding cutting segment. Suitably, the respective cutting segment has a recess adapted for a slotted slider, which sits rigidly in the recess when correctly positioned.

In order to enable a particularly simple replacement of the hydraulic clamping unit in the event that the hydraulic clamping unit becomes damaged or fails, the clamping unit is designed as a self-contained assembly which is mounted on the carrier. The design of the self-contained assembly additionally advantageously ensures that hydraulic fluid does not inadvertently leak from the clamping unit and contaminate the tool.

In a particularly advantageous variant, one or more of the above-mentioned aspects are combined with an embodiment of the tool described in the applicant's application DE 102014106516.6, which was not disclosed at the time of filing of the present application. This application also describes a tool for the lathe-and-lathe pulling of workpieces, which comprises a carrier to which a plurality of cutting segments, including hydraulic clamping units, can be fastened. The clamping screw is described in this application as a clamping element which actuates the hydraulic clamping unit. The clamping screw in this case presses against one or more pressure pistons of the hydraulic clamping unit. This actuating mechanism for a hydraulic clamping unit by means of a clamping screw, described in DE 102014106516.6, is combined with the above-described clamping by means of a clamping ring according to a first variant.

Furthermore, DE 102014106516.6 describes a tensioning bolt for clamping the cutting segment in the radial direction, which bolt acts on the cutting segment and clamps the cutting segment in the radial direction against the carrier when the hydraulic clamping unit is actuated. According to a second variant, the clamping mechanism with the tensioning bolt is coupled by means of a common clamping element (in particular by means of a rotary ring) to the common actuation of the plurality of hydraulic clamping units described herein. Reference is made in this respect to the disclosure of DE 102014106516.6, which is also hereby included in the present application.

Drawings

Exemplary embodiments of the present invention are described in more detail below based on the drawings. The following schematically shows:

fig. 1 shows a tool in a side sectional view;

fig. 2 shows a detail of the view according to fig. 1; and

fig. 3 shows the tool according to fig. 1 in a front view.

Detailed Description

Fig. 1 and 2 show a longitudinal section of a tool 2 along an axial direction a, the tool 2 comprising a carrier 4 extending radially (i.e. in a radial direction R), the carrier 4 being annular here and being fastenable to a machine tool, which is not shown in more detail. A plurality of cutting segments 6 are fastened on the outside of the carrier 4 in the radial direction R. The cutting segment serves in particular to accommodate a blade, which is not shown in greater detail here. Fig. 2 shows an enlarged detail of fig. 1, this part being indicated in fig. 1 by a rectangle with dashed lines. Fig. 3 shows the tool 2 in a front view. The tool 2 is a car-pull tool, which during operation rotates in the axial direction a around a rotational axis. The entire tool 2 is preferably designed in the manner of a disk. The extension of the tool in the radial direction R is a multiple, for example at least 5 times, of the extension in the axial direction a.

The cutting segments 6 each have a segment base 8 on the inside in the radial direction R, the segment base 8 here comprising two shoulders 10, the shoulders 10 being arranged on opposite sides of the respective cutting segment 6 in the axial direction a. In order to fix the cutting segment 6 by clamping, the tool 2 comprises a clamping ring 12, the clamping ring 12 extending in the axial direction a in the circumferential direction U, just like the carrier 4. Fig. 1 and 2 show the clamping ring 12 in the clamping position. The segment base 8 is clamped in a clamping groove 14, which clamping groove 14 is formed by the clamping ring 12 and the carrier 4. The clamping ring 12 and the carrier 4 have extensions 15, which extensions 15 point outwards in the radial direction R and are spaced apart from one another by a distance a 1.

The clamping ring 12 exerts an axial force K1 (also referred to as clamping force) in the axial direction a, which serves to hold the cutting segment 6. This axial force K1 is generated in particular by the wedge 16, the wedge 16 being displaceable in the radial direction R. For this purpose, the clamping wedge 16 has a wedge surface 18, which wedge surface 18 is inclined obliquely upward with respect to the axial direction a and presses against a wedge bearing surface 20 of the clamping ring 12. In order to generate the axial force K1 directly, a plurality of hydraulic clamping units 21 are mounted on the carrier 4. The hydraulic clamping unit 21 can be used to generate a radial force K2, the radial force K2 acting outwards in the radial direction R by means of a hydraulic fluid (not shown here in greater detail), wherein the radial force K2 can be used to displace the wedge 16 in the radial direction R. Due to the fit between the wedge surface 16 and the wedge bearing surface 18, said radial force K2 is then at least partially transformed into an axial force K1.

In the exemplary embodiment shown here, the clamping ring 12 and the radial extension 15 of the carrier 4 each merge into a flange 22, which flange 22 narrows the clip groove 14 in an outer section in the radial direction R and in this way forms an entry slot 24 on the periphery of the tool, which can be used to enter the clip groove 14. Furthermore, the flanges each comprise a clamping face 26 directed towards the clamping groove 14 and surround the segment base 8 such that said clamping face 26 abuts against an outwardly directed shoulder face 28 of the shoulder 10 of the cutting segment 6. Similar to the above-described conversion of the radial force K2 into the axial force K1, the partial conversion of the axial force K1 into the radial force K3 directed inward in the radial direction R occurs in this way. This results in particular in an inward pulling of the cutting segments 6. As is particularly evident from fig. 2, the respective flange 22 of the extension 15 surrounds the segment base 8 in the manner of a tongue and thus clamps the base in the axial direction a and in the radial direction R.

In order to bring the clamping wedge 16 into the clamping position, the tool 2 comprises a clamping element 30, the clamping element 30 being designed here as a rotary ring, which serves to actuate the hydraulic clamping unit 21. For this purpose, in the exemplary embodiment shown here, the clamping element 30 has an eccentric actuating element 34, which is embodied here as a step. Said step is pushed into the clamping unit 21 during rotation, so that a plurality of pressure pistons (not shown in more detail) are operated in order to displace the hydraulic fluid present in the hydraulic clamping unit 21, whereupon the pressure pistons (likewise not shown here) are then driven out, which finally pushes the wedges 16 outwards.

For releasing, the clamping element 30 is transferred into the release position, whereupon the hydraulic force on the wedge 16 is reduced and the wedge 16 can be displaced inwards in the radial direction R. The catch wedge 16 is automatically pushed back, for example by means of a return spring, which is not shown in greater detail here. Due to the pushed-back wedge 16, the distance a1 between the clamping ring 12 and the carrier 4 can be enlarged, so that the cutting section 6 can be removed from the clamping groove 14. In order to prevent the clamping ring 12 from falling off from the tool 2 in the process, a pull-out protection 36 is additionally arranged in the axial direction a relative to the carrier 4, which pull-out protection is designed here in the form of a ring and prevents a displacement of the clamping ring 12 beyond the maximum distance a_max. Suitably at least the distance a1 plus the width of the shoulder 10 in the axial direction a.

In order to correctly position the cutting segment 6 relative to the carrier 4 in the circumferential direction U during insertion, a slotted slider 38 is additionally screwed onto the carrier 4, the respective cutting segment 6 being placeable on the carrier 4 in particular in the radial direction R. For this purpose, a suitable recess is introduced into the cutting segment 6, in a manner not shown here in greater detail, in which recess the slotted slider 38 sits when correctly positioned.

Claims

1. A tool (2) for chip removing machining a workpiece, comprising a carrier (4) which is rotated about an axial direction during operation and further comprising a plurality of cutting segments (6) which are fastened to the carrier (4) in a radial direction,

at least one hydraulic clamping unit (21) for fixedly clamping at least one of the cutting segments (6) on the carrier (4) is mounted on the carrier (4),

the method is characterized in that:

the cutting segments (6) can be clamped together on the carrier (4) by means of a clamping ring (12) in a reversible and fixed manner, and

for this purpose, the clamping ring (12) can be displaced in the axial direction relative to the carrier (4) by means of the hydraulic clamping unit (21).

2. Tool (2) according to claim 1,

the method is characterized in that:

the carrier (4) and the clamping ring (12) are spaced apart from one another in the axial direction and form a clamping groove (14), in which clamping groove (14) the cutting section (6) is seated.

3. Tool (2) according to claim 2,

the method is characterized in that:

each of the cutting segments (6) has a segment base (8), the segment base (8) being seated in the clamping groove (14), and at least one component selected from the group consisting of the carrier (4) and the clamping ring (12) has a circumferential collar (22), the collar (22) narrowing the clamping groove (14) in a radially outer section and surrounding the segment base (8).

4. Tool (2) according to claim 3,

the method is characterized in that:

the flange (22) has an inclined clamping surface (26), the inclined clamping surface (26) being directed inwardly relative to the clip groove (14) and acting on an outwardly directed, inclined shoulder surface (28) of the segment base (8).

5. Tool (2) according to claim 1,

the method is characterized in that:

a conversion element (16) is arranged on the carrier (4), the conversion element (16) being designed to convert a radial movement generated by the hydraulic clamping unit (21) into an axial movement of the clamping ring (12).

6. Tool (2) according to claim 5,

the method is characterized in that:

the shifting element has a clamping wedge (16), wherein the clamping wedge (16) can be displaced in the radial direction by means of the hydraulic clamping unit (21) and acts with a wedge surface (18) on a wedge bearing surface (20) of the clamping ring (12) in order to displace the clamping ring axially.

7. Tool (2) according to claim 1,

it is characterized in that

A pull-out limiter (36) is provided, which defines a maximum axial pull-out of the clamping ring (12) during the removal of the cutting segment (6).

8. Tool (2) according to claim 1,

it is characterized in that

A clamping element (30) is provided for generating a hydraulic pressure by means of the hydraulic clamping unit (21) and can furthermore be switched between a clamping position and a release position in order to fixedly clamp and release the cutting segment (6).

9. Tool (2) according to claim 8,

it is characterized in that

A plurality of hydraulic clamping units (21) are provided, which can be actuated jointly by means of the clamping elements (30).

10. Tool (2) according to claim 8 or 9,

the method is characterized in that:

the clamping element (30) is formed as a rotary ring which can be switched by rotation between the clamping position and the release position.

11. Tool (2) according to claim 8 or 9,

the method is characterized in that:

for switching between the clamping position and the release position, at least one eccentric actuating element (34) is mounted on the clamping element (30) in order to actuate the hydraulic clamping unit (21) when switching to the clamping position.

12. Tool (2) according to any one of claims 1-9,

the method is characterized in that:

for each of the cutting segments (6), at least one slotted slider (38) is fastened on the carrier (4) in order to position the cutting segment (6) in the circumferential direction.

13. Tool (2) according to any one of claims 1-9,

the method is characterized in that:

the hydraulic clamping unit (21) is a self-contained assembly which is mounted on the carrier (4).