EP3370903A1

EP3370903A1 - Chamfering tool with guide for eliminating vibrations

Info

Publication number: EP3370903A1
Application number: EP16788699.3A
Authority: EP
Inventors: Ulrich Rattunde
Original assignee: Rattunde AG
Current assignee: Rattunde AG
Priority date: 2015-11-03
Filing date: 2016-11-01
Publication date: 2018-09-12
Also published as: US20180236560A1; US11045877B2; WO2017076833A1; JP6791957B2; MX2018005558A; DE102015118769A1; CN108472734A; CA3003934C; CA3003934A1; CN108472734B; JP2018534162A; HK1255126A1

Abstract

The invention relates to a cutting machine with a receiving area for a tube section and with a tool head (1) which can be rotated relative to the receiving area about a longitudinal axis (L), has at least one cutting tool (6) for machining a tube section end (40) of the tube section located in the receiving area, and has a support component (2), wherein the support component faces the receiving area and has an annular component (3) which rotates relative to the support component (2) about the longitudinal axis (L) and is designed to be randomly supported on a tube wall (42, 42) of the tube section end (40). The invention further relates to a corresponding method for reducing vibrations.

Description

Chamfering tool with guide for vibration elimination

The invention relates to a cutting machine and a method for reducing in particular regenerative rattling of the cutting machine.

Cutting machines are well known in the art in the form of rotating tool heads for pipe ends. A tool head is disclosed, for example, in EP 2 106 313 B1. In DE 2541414 a hand-operated tool for chamfering a pipe end is disclosed. The tool is operated at low speed. The tool is guided by radially outer parts that extend beyond the cutting edges and a guide means, are mounted on the rotatable discs. Cutting machines with rotating tool heads are oscillatory bodies, with the help of which cut-to-length pipe sections are reworked. In particular, a pipe section end can be provided with a chamfer. To form chamfers, the tool heads are fed in extension of the longitudinal axis of the pipe section to the pipe section end, rotate the tool heads and have one or more cutting plates, with the help of both an inner or Außenfase and a plan dimension are applied to the pipe end. When applying the bevels and the plan dimension chips are lifted from the pipe end.

The tool head is located at the end of a rotating spindle and together with the spindle is a vibratory body. Basically, both the outer and the inner walls of the pipe section ends are never formed exactly circular, so it comes to load changes during the cutting process. If the load changes are in the range of the natural frequency of the tool head mounted on the spindle, undesirable rattling may occur. On the one hand, the rattle loads the cutting machine, on the other hand, the end of the pipe section to be produced becomes wavy, and quality losses occur. Maybe the machined tube end will even become unusable. A special form of rattling is the so-called regenerative rattling. The self-oscillation of the tool head is stimulated again and again by the already generated surface waviness, which is formed by the same cutting tool in the already pre-machined surface. It creates a rattle that is getting stronger. To avoid regenerative rattling, there are various approaches in the art.

For example, in multi-bladed milling tools or friction tools, the blades are arranged at different distances from each other, and thus the natural frequency is constantly changed during cutting. The consequence of this is that the regenerative rattle ideally does not occur at all. With single-edged tools a change of the cutting distance is of course not possible. It is known, however, that a rotational speed of the rotating cutting tool is constantly changing rapidly, but this can lead to heavy machine loading at high frequencies.

In addition, active damping systems are known in which the vibrations are detected electronically and the natural frequency of the system is changed by means of an additional mass. In addition, there are passive damping systems in which hydraulic dampers or additional spring-mass systems are provided, so-called absorbers, which largely cancel the resonance frequency. However, the systems mentioned to avoid regenerative rattling are extremely complicated and also maintenance-intensive.

It is therefore an object of the invention to provide a cutting machine available in which the regenerative rattle less, preferably does not occur and their maintenance is not increased, at least not significantly increased, as well as a simple method for reducing regenerative rattling To make available.

In the first aspect, the object is achieved by a cutting machine having the features of claim 1.

The cutting machine according to the invention comprises a receptacle for a pipe section and a tool head, which is rotatable relative to the receptacle about a longitudinal axis and which has at least one cutting tool for machining a pipe section end of the pipe section located in the receptacle. The pipe section is positionally fixed relative to a frame of the cutting machine in the receptacle, especially during machining, fixable. The receptacle is preferably provided fixed in position relative to the frame of the cutting machine. In particular, the tool head is movable back and forth relative to the receptacle in a longitudinal direction of the receptacle and the tube section accommodated therein before and after the cutting process. The tool head is mechanically driven, preferably by an electric motor. The tool head is designed to be movable relative to the frame. The cutting machine processes a plurality of, preferably dozens, hundreds or more, pipe sections at short intervals of a few seconds in succession. The cutting machine is preferably located on a floor during machining.

According to the invention, a support component pointing in the direction of the receptacle is provided on the tool head, which has a ring component which is rotatable about the longitudinal axis relative to the support component and which is intended for random support on a pipe wall of the pipe section end. The support member and the cutting means, preferably inserts, are relatively rotationally fixed to each other during machining.

The support member is a component for reducing or avoiding regenerative rattle. The support member may be formed in particular in the form of a dome, and the ring member is preferably rotatable outside the mandrel in the mandrel embodiment of the support member, wherein an outer diameter of the ring member in cross-section perpendicular to the longitudinal axis is smaller than an inner diameter of the pipe end, but an outer diameter of the ring member is greater than a mandrel diameter, in such a way that during the machining process introduced into the end of the pipe mandrel with its ring member at random abuts the inner wall of the pipe section end and an interruption of the vibration process of the tool head is generated by the concerns. The pipe end is rotated relative to the tool head with its at least one cutting tool. In this case, in a variant of the cutting machine, the tool head can be held in space and the pipe section can be rotated, while in another variant the pipe section is held in space and the tool head is rotated. It is also a combination of both variants conceivable. The tool head processes by means of the at least one cutting tool walls of the pipe section, in particular brings the cutting tool on inner and Außenfasen and a planned dimension on the pipe section end. The pipe section is formed in particular metallic, in particular it is an iron or steel workpiece. In principle, however, other materials are conceivable. The tube has over its entire length a preferably circular outer or inner diameter. However, the cutting machine is also suitable for machining pipe ends that are not exactly circular, where basically under circular here is not the exact mathematical circle to understand, but also small deviations in the micrometer range or larger of the mathematical exact circular shape are included. The cutting machine and in particular the method according to the invention are also suitable for machining pipe sections with such not exactly circular inner and outer diameters.

The tool head is excited to vibrate during machining. Due to the vibrations of the mandrel is also moved out of its longitudinal axis, and the ring member abuts against the inner wall of the pipe section. The outer diameter of the ring member is sized so that it is slightly smaller than an inner diameter of the pipe section, so that the mandrel with ring member can be introduced without contact in principle in the end of the pipe section. By the contact of the ring member with the inner wall of the pipe end portion of the vibration process is disturbed, and in particular the periodicity of the excitation of the natural vibration of the tool head is interrupted, and there is no regenerative rattling.

In another embodiment of the invention, the tool head of the cutting machine according to the invention is provided with a support member designed as a sleeve, wherein the ring member is rotatably disposed inside the sleeve and an inner diameter of the ring member is greater than an outer diameter of the pipe end, so that the socket from the outside to the pipe end can be performed. However, the principle for suppressing the regenerative rattle is similar to the embodiment with the mandrel. The excited to minor oscillations movements tool head abuts with its ring member to the outer wall of the pipe section end, and the vibration behavior of the tool head is interrupted. It can not come to a rocking of the vibration. In a particularly favorable embodiment of the invention, a support surface of the ring component, which is in the embodiment of the dome, an outer surface of the ring member or in the embodiment as a socket an inner surface of the ring member, provided with a profile. The support surface of the ring member is therefore not exactly circular in each cross section along the longitudinal direction. Preferably, the profile in cross-section recesses in the direction away from the pipe wall. These depressions or recesses preferably extend along the entire longitudinal direction of the ring component. The recesses make it possible that chips do not jam between the ring member and the pipe wall, but can be discharged through the recesses in the pipe interior or to the outside. Preferably, the profile has a meandering shape in cross section. In this case, the recesses may extend exactly parallel to the longitudinal direction of the ring component, but it is also conceivable that the recesses extend obliquely to the longitudinal direction of the ring member. However, other configurations of the profile are conceivable, for example along the circumference of different width recesses or recesses and different widths elevations as well as not exactly rectilinear recesses and / or elevations, but undulating or conically widening or tapering elevations or recesses.

Conveniently, the ring member is mounted in a ball bearing on the support member. Thus, the ring member is rotatably disposed about the longitudinal axis of the tool head. However, the ring member does not allow swinging movement, i. H. Movements perpendicular to the longitudinal axis relative to the support member or the tool head.

Conveniently, the ring member is interchangeable by the support member having a cap which is removable and allows the replacement of the ring member against a larger diameter or smaller ring member.

With regard to the method, the object is achieved by a method having the features of claim 9. The method is particularly suitable for carrying out with one of the cutting machines described above.

The method is intended in particular for reducing vibrations, in particular the regenerative rattling of a cutting machine. Under cutting machine is to be understood in particular a machine for processing pipe sections ends. According to the invention, a pipe section is rotated relative to a tool head with at least one cutting tool. The tool head reams walls of the pipe end by means of the at least one cutting tool. During machining, the tool head is usually excited to vibrate, and the tool head is by means of a support member, which has a ring member rotating about the longitudinal axis, supported on the wall of the pipe section, whereby the vibration excitation is interrupted and in particular a regenerative rattling is avoided. Also with regard to the method, the invention makes use of the idea of suppressing oscillations which build up by periodic excitation, in that a disturbance of the oscillating process is produced by the supporting component, which is preferably in the form of a dome or also in the form of a bush in or around the Pipe end is guided. Even with low oscillatory movements of the tool head from the longitudinal axis, the support member generates by means of its ring member a contact with the pipe end, thereby the vibration process is interrupted, and it can not come to a rocking of the swinging motion.

The ring member is rotatably mounted relative to the tool head, so that the angular velocity of the ring member is reduced in contact with the wall of the pipe end, while a speed of the tool head by touching the ring member with the wall of the pipe end need not change. As a result, the cutting machine is hardly or only very slightly loaded, since no speed changes of the spindle need to take place, which rotates the tool head.

The invention will be described with reference to an embodiment in six figures. 2 shows a perspective view of the tool head in FIG. 1, FIG. 3 shows a front view of the tool head in FIG. 2,

, 4 shows a sectional view of the tool head along the line IV-IV in FIG. 3, wherein a mandrel of the tool head according to the invention is additionally inserted into a pipe section end, FIG. 5 shows a sectional view according to FIG. 4 without pipe section end, 6 shows a perspective view of the tool head inserted in a pipe section end according to FIG. 4.

A tool head 1 shown in FIG. 1 additionally has a mandrel 2 protruding along a longitudinal axis L of the tool head, for example a tool head known from EP 2 106 313 B1, on the outer end of which a ring component 3 is rotatably mounted. The ring member 3 and the mandrel 2 are formed substantially circular in cross-section perpendicular to the longitudinal axis L and arranged concentrically about the longitudinal axis L of the tool head 1. At a opposite end of the mandrel 2 of the tool head 1, a spindle receptacle 4 is provided, with which the tool head 1 can be exchangeably attached to a controlled rotating (not shown) spindle.

The tool head 1 in FIG. 1 has four cutting plates 6, three of which can be seen in FIG. 1. The cutting plates 6 are intended for machining a pipe section end 40 having a circular inner diameter and a circular outer diameter in cross-section. Two of the cutting plates 6 are intended for attachment of an outer bevel at the pipe end 40 and two other cutting plates 6 for attachment of a Innenfase at the pipe end 40. The pipe end 40 is preferably made of metal, more preferably of steel, but other materials may be provided. The tool head 1 can also have a different number of cutting inserts 6, in particular one, two, three or a larger number of cutting inserts 6, compared to the embodiment in FIG. 1. The tool head 1 and the pipe end 40 rotate as shown in FIG. 4 about the longitudinal axis L relative to each other, while the pipe end 40 can be kept fixed in space relative to the tool head 1, while the tool head 1 rotates about the longitudinal axis L, but vice versa, but also the tool head 1 can be kept fixed in space, and the tube section end 40 can be rotated about the same longitudinal axis L. During the rotation process, the cutting plates 6 pick up chips from an outer wall 41 or an inner wall 42 of the pipe section end 40.

During the cutting process, load changes of the cutting forces can occur, for example because the outer wall 41 or the inner wall 42 is not exactly circular, which is actually always the case in reality, so that the lifted chips have slightly different thicknesses during the real machining process Even with an ideally circular pipe section end 40, it will cause load changes come that cause the tool head 1 initially offset in small oscillatory movements out of the longitudinal axis L out, but which can increase periodically by continuous relative rotation of the tool head 1 and pipe end 40 and thus lead to the so-called regenerative rattling.

The waviness of the outer wall 41 of the pipe section end 40 and the inner wall 42 of the pipe section end 40 periodically stimulates the tool head repeatedly to equal vibrations. Usually tool heads rotate at about 5,000 revolutions per minute, but there are also other numbers of revolutions conceivable. The tool head 1 is mounted on a rotating, aligned along the longitudinal axis L, not shown, spindle and can swing out of the longitudinal axis L. The vibration behavior of the tool head 1 is essentially determined by a rigidity c of the tool head 1 mounted on the spindle, a damping d and a mass m of the tool pulling head 1 with the spindle. In particular, a natural frequency figs of the tool head 1 is a function of these three parameters, this means eigenspeed figs the natural frequency at which the mounted on the spindle tool head 1 from the longitudinal axis L swings out. The invention makes use of the idea to introduce a disturbance into the natural vibration of the tool head 1 through the mandrel 2 with the ring component 3 rotatably mounted about the longitudinal axis L on the mandrel 2.

Fig. 2 shows the tool head 1 in Fig. 1 in a perspective view, which represents somewhat more clearly the circular cross-sectional configuration of the dome 2 with the rotatably mounted on the mandrel 2 ring member 3. In addition, two of the four inserts 6 can be seen. The cutting plates 6 are exchangeably mounted on the tool head 1. According to the invention, a support surface 20 surrounding the ring component 3 is not exactly circular in cross-section, but the support surface 20 has a meandering configuration in cross-section. That is, the exact circular cross-section is periodically interrupted by reductions in the radial direction inwards to the longitudinal axis L out, so that along the longitudinal axis L extending recesses 21 are provided in the outer wall of the ring member 3, extending over an entire longitudinal extent along the longitudinal axis L of the ring member 3 extend.

FIG. 3 shows the tool head 1 in FIGS. 1 and 2 in a front view, whereby the mandrel 2 which is circular in cross-section can be seen, as well as the ring component 3 projecting radially over a mandrel diameter, the outer support surface 20 of the ring component 3 being the one described above has a meandering shape deviating from the exact circular shape. In the cross section according to FIG. 3, radially outer elevations 22 of the ring component 3 form regions of an exact area Circular shape with a first larger radius, and the recesses 21 of the ring member 3 form areas of an exact circular shape with a second smaller radius. Both the smaller and the larger radius of the ring member 3 are each larger than the radius of the dome. 2

Fig. 4 shows the tool head 1 according to the invention in its intended use, while the mandrel 2 is inserted into the open pipe end 40, an inner diameter of the pipe section end 40 is greater than each diameter of the ring member 3, so that the mandrel 2 with the ring member 3 at more exact Introduction along the longitudinal axis L of a pipe section, the inner wall 42 of the pipe section end 40 is not touched. The ring member 3 is rotatably supported by a ball bearing 43 on the mandrel 2, but it is not radially reciprocable with respect to the longitudinal axis L of the tool head 1, the ring member 3 is exclusively rotatably mounted on the tool head 1. The mandrel 2 has a removable cap 44. After removing the cap 44, the ring member 3 may be replaced by another ring member, while the other ring member may in particular have a different large radius and thus be suitable for the processing of pipe sections 40 with other inner diameters.

During the cutting process, the cutting plates 6 pick up chips from the inner wall 42 and outer wall 41 of the pipe section end 40, respectively, and thus provide an inner or outer bevel 46, 45 on the edge of the pipe section end 40. During the Zerspannungsvorganges it may cause slight vibrations of the tool head 1, which cause the ring member 3 of the dome 2 makes contact with the inner wall 42 of the pipe section end 40 receives. As a result, the oscillatory process of the tool head 1 is disturbed, and the tool head 1 is not periodically excited for self-oscillation. Due to the rotatable mounting of the ring member 3 on the mandrel 2, however, the actual cutting operation is not interrupted, because the ring member 3 generates only a very slight friction on the inner wall 42, on the other hand, the inner wall 42 is not damaged, since the ring member 3 is not along the inner wall 42 grinds, but is transferred immediately in contact due to its low mass relative to the tool head 1 from the rotational movement to a standstill.

In Fig. 5, the schematic structure of the tool head 1 according to the invention in Fig. 4 without the pipe section end 40 is shown, in particular, the rotatable ring member 3 is shown with the rotating ball bearing 43 and the cap 44 of the dome 2, which are removably bolted to a spike 50 can and which makes it possible to decrease the cap 44 to replace the ring member 3. On the left in FIG. 4, the mandrel 2 opposite spindle receptacle 4 can be seen.

Fig. 6 shows the tool head 1 with the pipe section end 40 in operation, the spindle is not shown, but it can be seen that the mandrel 2 is invisibly inserted into the pipe section end 40 and the inserts 6 already recognizable the Außenfase 45 and not recognizable Inner bevel 46 have applied to the pipe section end 40. The pipe section is formed even longer along the longitudinal axis L than the pipe section end 40 shown in FIG.

reference numeral

tool head

2 thorn

3 ring component

4 spindle receptacle

6 inserts

20 support surface

21 recesses

22 radially outer elevations

40 pipe ends

41 outer wall

42 inner wall

43 ball bearings

44 cap

45 outer bevel

46 inner bevel

50 thorns c stiffness

d damping

m mass figs intrinsic frequency of the tool head

L longitudinal axis

Claims

claims

1 . Cutting machine with

a receptacle for a pipe section and

a tool head (1) which is rotatable relative to the receptacle about a longitudinal axis (L) and the at least one cutting tool (6) for processing a

Pipe end (40) of the tube section located in the receptacle and having a pointing in the direction of the receiving support member (2), the one with respect to the support member (2) about the longitudinal axis (L) rotatable

Ring component (3), which is intended for random support on a pipe wall (42, 42) of the pipe section end (40).

2. Cutting machine according to claim 1,

characterized in that the support member is formed as a mandrel (2) and the ring member (3) outside the mandrel (2) is rotatably arranged and an outer diameter of the ring member (3) in cross-section perpendicular to the longitudinal axis (L) smaller than an inner diameter of the pipe section end (40) is.

3. Cutting machine according to claim 1 or 2,

characterized in that the support member is formed as a socket and the

Ring member (3) is rotatably disposed inside the sleeve and an inner diameter of the ring member (3) is greater than an outer diameter of the pipe section end (40).

4. Cutting machine according to one of claims 1, 2 or 3,

characterized in that a support surface (20) of the ring member (3) has a profile.

5. Milling machine according to one of the preceding claims,

characterized in that the profile in cross-section recesses (21) in

Direction away from the pipe wall (41, 42).

6. Cutting machine according to one of claims 1, 2 or 3,

characterized in that the profile has a meandering shape in cross section.

7. Cutting machine according to one of the preceding claims,

characterized in that the ring member (3) in a ball bearing (43) on

Supporting member (2) is mounted. Cutting machine according to one of the preceding claims,

characterized in that the ring member (3) is interchangeable with another ring member having a different radius.

Method for reducing vibrations, in particular a regenerative rattling of a cutting machine, by

a pipe section relative to a tool head (1) with at least one

Cutting tool (6) rotates,

the tool head (1) by means of the at least one cutting tool (6)

Cutting walls (41, 42) of the pipe section end (40),

the tool head (1) is excited to oscillate during machining, the tool head (1) by means of a support member (2), the one to a

Having longitudinal axis (L) rotating ring member (3), on one of the walls (41, 42) of the pipe section end (40) is supported, thereby interrupting an excitation of the vibrations.

0. Method according to claim 9,

characterized in that the ring member (3) has an angular velocity which decreases upon contact with the wall (41, 42) while a rotational speed of the tool head (1) does not change due to the contact.