Machine tools abstract
The invention relates to a drilling tool for machine tools and
to a method for the production thereof. The drilling tool has at
least one chip conveyor groove (16) and at least one functional
channel (20). In order to produce the body of the drill (10), the
wall of a tubular metal blank is simultaneously impinged upon by
substantially radially oscillating form-giving forces in several
forming sections spread over the periphery, moving in an axial direction
along the surface of the blank, whereby at least one chip conveyor
groove (16) is shaped and at least one functional channel (20) is
formed. When the chip conveyor grooves (16) are formed on at least
two interspaced forming sections in a peripheral direction in the
wall of the blank (50), the parts of the wall in the area of two
opposite-lying chip conveyor grooves (16) come to rest against each
other in a sealed manner, defining at least two functional channels
(20 24) on the inner surfaces thereof. The joint (40) thus formed
can be closed by means of cold welding or soldering.
Machine tools claims
What is claimed is:
1. A method for the production of a drilling tool, onto a body
of a drill of which is formed at least one chip conveyor groove
and at least one functional channel, whereby a tubular blank is
loaded on its wall simultaneously by several forming segments distributed
over a periphery and moving axially along a blank surface with radially
oscillating shaping forming forces, thereby forming at least one
chip conveyor groove and at least one of a functional channel and
a joint provided inside of the body of the drill, wherein the blank
is automatically rotated about its axis during the forming process
under the action of an axial feed force.
2. The method according to claim 1 wherein the tubular blank comprises
a metal tubular blank or a tubular blank constructed as a raw product
out of a sinterable material.
3. The method according to claim 1 wherein the tubular blank is
loaded with the oscillating shaping forming forces on the forming
segments moving both axially and also in peripheral direction along
the blank surface, thereby producing the at least one chip conveyor
groove as a helically shaped chip conveyor groove and the at least
one functional channel as a helically shaped functional channel.
4. The method according to claim 1 wherein the body of the drill
is formed in steps in several passes.
5. the method according to claim 4 wherein the blank is tempered
and annealed between two passes.
6. The method according to claim 1 wherein the blank is axially
moved relative to the forming segments during the forming process.
7. The method according to claim 1 wherein the blank is rotated
about its axis relative to the forming segments during the forming
process.
8. A method for the production of a drilling tool, onto the body
of a drill of which is formed at least one chip conveyor groove
and at least one functional channel, whereby a tubular blank, in
a cold state, is loaded on its wall simultaneously by several forming
segments distributed over a periphery and moving axially along a
blank surface with radially oscillating shaping forming forces,
thereby forming two oppositely lying chip conveyor grooves and at
least one of a functional channel and a joint provided inside of
the body of the drill, whereby the chip conveyor grooves are formed
into the wall of the tubular blank by at least two of the forming
segments, which are spaced from one another in peripheral direction,
so that portions of the wall in the area of the two oppositely lying
chip conveyor grooves provide their inner wall surface sealingly
against one another forming a joint, wherein the wall portions,
which rest against one another in the area of the joint, are cold-welded
or are soldered to one another during the forming process.
9. The method according to claim 1 wherein the oscillating frequency
of the forming forces is 100 to 2000 Hz.
10. The method according to claim 1 wherein the oscillating forming
forces are produced by a kneading and hammering works with forming
tools of a rotary kneading or a rotary hammering machine, which
forming tools extend over each one of the forming segments.
11. The method according to claim 10 wherein the at least one
chip conveyor groove is produced by a shaping forming tool adapted
to the contour of the chip conveyor groove.
12. The method according to claim 11 wherein an outlet of the
chip conveyor groove at the end of a passage path is determined
by an inlet contour of the shaping forming tool.
13. The method according to claim 10 wherein the blank moved in
feed direction is automatically rotated about its axis by the shaping
forming tool, which engages the partially finished helically shaped
chip conveyor groove, which is to be produced.
14. The method according to claim 10 wherein the blank is rotated
by a motor about its axis relative to the kneading or hammering
works in dependency of its axial feed path.
15. The method according to claim 1 wherein chip conveyor grooves
are formed by at least two of the forming segments, which are spaced
from one another in peripheral direction, into the wall of the tubular
blank in such a manner that inner wall portions in the area of two
opposite-lying chip conveyor grooves sealingly abut one another
on their inner surface thereby defining the joint.
16. The method according to claim 15 wherein the wall portions,
which abut one another in the area of the joint, are cold-welded
during the forming process.
17. The method according to claim 15 wherein the inner wall portions,
which abut one another in the area of the joint, are soldered to
one another.
18. The method according to claim 17 wherein the solder needed
for the soldering process is applied or inserted prior to the forming
process onto or between the inner wall portions, which are to be
connected with one another, and is heated to fusion or melting temperature
during or after the forming process.
19. The method according to claim 1 wherein a foreign medium,
including at least one of solder wire, solder paste, a separating
means, a damping means or an inner coating, is placed into the inside
of the blank prior to the forming process.
20. The method according to claim 1 wherein at least one insert
is placed into the blank in the area of the functional channel,
and is embedded in the functional channel during the forming process.
21. The method according to claim 20 wherein the insert is removed
from the functional channel after the forming process.
22. The method according to claim 20 wherein the insert comprises
a rod-shaped, wire-shaped, tubular or pearl-chain insert.
23. The method according to claim 20 wherein the insert comprises
metal, ceramics, plastic or polyfluorotetraethylene.
24. The method according to claim 1 wherein a cutting head is
formed on or secured to a front-side end of the body of the drill
and a drill shank is formed or secured to a rearward end of the
body of the drill.
25. The method according to claim 1 wherein a drill shank is formed
on or secured to a rearward end of the body of the drill.
26. The method according to claim 24 wherein at least one of the
cutting head and the drill shank are formed on the body of the drill
by a swage without generating metal chips.
27. The method according to claim 24 wherein the cutting head
is welded to the body of the drill by resistance welding.
28. The method according to claim 24 wherein the drill shank is
welded to the body of the drill by friction welding.
29. The method according to claim 24 wherein at least one of the
cutting head and the drill shank are soldered or glued to the body
of the drill.
30. The method according to claim 24 wherein the cutting head
and the drill shank are fastened by at least one tie rod to the
body of the drill, the tie rod having a common axis with and penetrating
through the body of the drill in the area of the functional channel.
31. The method according to claim 30 wherein the tie rod is tensioned
by screwing.
32. The method according to claim 30 wherein the tie rod is tensioned
by heating and subsequent cooling off.
33. The method according to claim 30 wherein the tie rod is hollow.
34. The method according to claim 30 wherein the tie rod has an
outer contour supported in the functional channel.
35. The method according to claim 1 wherein the material of the
body of the drill is after the forming process heat-treated, hardened,
sintered or is provided with a surface coating.
36. A drilling tool for machine tools comprising a body of a drill,
a cutting head arranged on a front side on the body of the drill,
and a rearward drill shank, whereby the body of the drill includes
at least two chip conveyor grooves extending from the cutting head
over a part of its length, and at least two functional channels
extending from the cutting head to the drill shank and having a
triangular cross section with two or three curved boundary sides,
wherein the body of the drill is designed as a circularly worked
form part, and the functional channels form a joint at their boundary
surfaces, which face one another, the joint being closed off by
welding or soldering bridges.
37. The drilling tool according to claim 36 wherein at least one
of the cutting head and the drill shank are anchored to the body
of the drill with at least one tie rod penetrating through the body
of the drill.
38. The drilling tool according to claim 36 wherein the functional
channel includes two or three sharp-edged corners.
39. The drilling tool according to claim 36 wherein at least one
of the cutting head and the drill shank are welded, soldered, glued
or screwed to the body of the drill.
40. The drilling tool according to claim 36 wherein at least one
of the boundary sides is outwardly concavely curved.
41. A drilling tool for machine tools comprising a body of a drill,
a cutting head arranged on a front side on the body of the drill,
and a rearward drill shank, whereby the body of the drill includes
at least two chip conveyor grooves extending from the cutting head
over a part of its length, and at least two functional channels
extending from the cutting head to the drill shank and having a
triangular cross section with two boundary sides that are curved
outwardly concavely and a third boundary side that is curved convexly,
wherein the body of the drill is designed as a circularly worked
form part, and the functional channels form a joint at their boundary
surfaces, which face one another, the joint being closed off by
welding or soldering bridges.
42. The drilling tool according to claim 36 wherein at least the
two chip conveyor grooves are defined at their flanks by helically
curved lands having a partial-cylindrical outer surface, and the
functional channels are each arranged in one of the lands.
43. The drilling tool according to claim 42 wherein the functional
channels include an outer, outwardly convex boundary side, which
is partially concentric with respect to the partial-cylindrical
outer surface.
44. A drilling tool for machine tools comprising a body of a drill,
a cutting head arranged on a front side on the body of the drill,
and a rearward drill shank, whereby the body of the drill includes
at least two chip conveyor grooves formed into the body and extending
from the cutting head over a part of its length, with an outer,
outwardly convex boundary side, which is partially concentric with
respect to the partial-cylindrical outer surface and at least two
functional channels extending from the cutting head to the drill
shank and having triangular cross sections with two inner boundary
sides, which follow the outer boundary side, and are outwardly at
least partially concave, and meet in an acute-angled triangular
corner pointing toward the axis of the body of the drill, wherein
the body of the drill is designed as a circularly worked form part,
and the functional channels form a joint at their boundary surfaces,
which face one another, the joint being closed off by welding or
soldering bridges.
45. The drilling tool according to claim 44 wherein the two inner
boundary sides extend essentially parallel with respect to the respectively
adjacent flank portions of the chip conveyor grooves.
46. The drilling tool according to claim 42 wherein triangular
corners of the two adjacent functional channels, which corners face
one another, are separated from one another by the joint.
47. The drilling tool according to claim 46 wherein the joint
extends essentially parallel with respect to a base of the groove
of two chip conveyor grooves, which are adjacent to one another.
48. The drilling tool according to claim 42 wherein the body of
the drill includes three chip conveyor grooves defined at their
flanks by the helically curved lands, and one of the functional
channels comprises an axis-centrally arranged functional channel,
having triangular corners that taper pointedly radially outwardly.
49. The method according to claim 1 wherein at least one of the
cutting head and the drill shank are formed on the body of the drill
by one of a compression tool, resistance welding, friction welding
or solder so that chips of material are not formed or separated
from the body during manufacturing thereof.
50. The drilling tool according to claim 36 wherein the functional
channels end in the area of a shank-side outlet of the chip conveyor
grooves steplessly in an enlarged center supply channel.
51. The drilling tool according to claim 36 wherein at least one
of the functional channels is loaded with a cooling lubricant.
52. The drilling tool according to claim 36 wherein at least one
of the functional channels is equipped with at least one wire-shaped,
tubular or cable-shaped insert made of at least one of metal, ceramic
material and plastic.
53. The drilling tool according to claim 36 wherein at least one
of the functional channels is filled completely or partially with
a filler.
54. The drilling tool according to claim 42 wherein the lands
have outer coat side recesses for receiving wear-resistant support
elements, which project over the partial-cylindrical outer surface.
55. The drilling tool according to claim 30 wherein the lands
have recesses extending in longitudinal direction of the grooves
to receive reinforcing or vibration-hindering, wear-resistant support
elements.
56. The drilling tool according to claim 42 wherein at least one
of the flanks of the chip-conveyor grooves is sharp-edged toward
the adjacent land outer surface.
Machine tools description
The invention relates to a drilling tool for machine tools comprising
a body of a drill, a cutting head arranged on the front side on
the body of the drill, and a rearward drill shank, whereby the body
of the drill has at least one chip conveyor groove extending from
the cutting head over a part of its length, and, if necessary, at
least one functional channel extending from the cutting head to
the drill shank. The invention relates furthermore to a method for
the production of such a drilling tool.
The known drilling tools of this type are usually produced by a
chip-removing method, like turning, milling and drilling. The functional
channels are produced in the body of the drill with the aid of a
deep-hole drill and receive thereby a circular cross section. Mainly
in the case of small drill diameters it is often difficult to house
functional channels with a sufficiently large cross-sectional surface
in the body of the drill. Furthermore the high production expense
is felt to be disadvantageous in the known drilling tools.
Based on this the basic purpose of the invention is to develop
a drilling tool with novel contours and a method for a particularly
simple production of such drilling tools.
The inventive solution is based on the thinking that the body of
the drill with its chip conveyor grooves and its functional channels
can be chiplessly produced in a particularly simple manner. In order
to achieve this, it is suggested according to the invention that
a tubular blank, preferably in the cold state, is loaded on its
wall simultaneously on several segments distributed over the periphery
and moving axially along the blank surface with radially oscillating
shaping forming forces, thereby forming at least one chip conveyor
groove and at least one functional channel and/or at least one joint
inside of the body of the drill. The tubular blank can thereby consist
either of a ductile metal, for example of steel, or can be constructed
as a raw product out of a sinterable material.
The often desired helical shape of the body of the drill is made
possible by the tubular blank being loaded with oscillating shaping
forming forces on forming segments moving both axially and also
in peripheral directions along the blank surface, thereby producing
at least one helically shaped chip conveyor groove and at least
one helically shaped functional channel.
The forming of the tubular blank into the finished body of the
drill can basically be done in one step. However, the problem arises
thereby that at certain points a relatively large forming degree
is necessary, which can result in a local tear formation. This is
particularly true in the outlet area of the chip conveyor groove.
In order to avoid this disadvantage, it is suggested according to
an advantageous development of the invention that the blank is formed
in steps in several passages. The blank can be tempered or annealed
between two passages in order to remove the material stresses, which
had built up earlier during the forming.
The blank is, during the forming process moved advantageously axially
relative to the stationary forming segments, and is, if necessary,
rotated about its axis relative to these segments. It is thereby
possible to automatically rotate the blank about its axis during
the forming process under the action of an axial feed force and
the forming forces acting on it.
The forming forces, which oscillate advantageously with a frequency
of 100 to 2000 Hz, are produced according to a preferred embodiment
of the invention by a kneading or hammering works with several forming
tools of a rotary kneading machine or a rotary hammering machine,
which forming tools extend over each one of the forming segments.
At least one chip conveyor groove is thereby produced by a shaping
forming tool adapted to the contour of the respective chip conveyor
groove, whereby the outlet of the chip conveyor groove at the end
of a passage path is determined by the inlet contour of the shaping
forming tool. The blank, which is moved in a feed direction, can
be automatically rotated about its axis by the shaping forming tool,
which engages the partially finished, helically shaped chip conveyor
groove, which is to be produced. It is basically also possible to
rotate the blank by means of a motor about its axis relative to
the kneading or hammering works in dependency of its axial feed
path. This enables also the creation of a variable helix pitch of
the chip conveyor groove and of the functional channel.
According to a further preferred embodiment of the invention chip
conveyor grooves are formed on at least two forming segments, which
are spaced from one another in a peripheral direction, into the
wall of the blank in such a manner that the wall portions in the
area of two opposite-lying chip conveyor grooves sealingly abut
one another on their inner surface thereby defining a joint. The
respective wall portions can be cold-welded to one another in the
area of the joint during the forming process when a chemically activated,
oxide-free surface exists at the contacted points. The two wall
portions, which abut one another in the area of the joint, can also
be soldered to one another. Solder or soldering paste must, prior
to the forcing process, be moved in between the wall portions which
are to be connected, and must during or after the forming process
be heated to a fusion or melting temperature.
Besides the soldering wire or the soldering paste, it is also possible
to move in addition other foreign media, like separating means,
damping means, or an inner coating into the inside space prior to
the forming process. Furthermore at least one shaping insert can
be placed into the blank, and can be embedded into the functional
channels during the forming process. Rod-shaped, wireshaped, tubular
or pearl-chainlike inserts of metal, ceramics, plastic and/or polyfluorotetraethylene
can be used thereby. Depending on the use, the inserts can remain
in the functional channels or can again be removed therefrom.
A cutting head is formed on or fastened to the front end of the
body of the drill and a drill shank on or to the rearward end. It
is thereby basically possible that the cutting head is formed chiplessly,
preferably with the aid of a compression tool or swage to the body
of the drill. As an alternative it is possible for the cutting head
and/or the drill shank to be welded to the body of the drill by
resistance welding and/or by friction welding. A soldered or glued
connection is also possible at this point.
A further alternative embodiment of the invention provides that
the cutting head and the drill shank are fastened with at least
one tie rod to the body of the drill, which tie rod penetrates through
the body of the drill preferably in the area of a functional channel.
The tie rod can thereby be tensioned or clamped by screwing, wedging
or compressing. It is furthermore possible to initially tension
or prestress the tie rod by heating and subsequent cooling off.
It is fundamentally also possible to use a tie rod having a hollow
design. In reverse, the tie rod can have an outer contour supported
in a functional channel leaving outer cavities open.
The material of the finished body of the drill is after the forming
process advantageously heat-treated, hardened, sintered, and/or
has a slidable and wear-resistant surface coating.
The body of the drill is in the drilling tools of the invention
designed as a form part produced out of a tubular blank by rotary
kneading or rotary hammering, whereby the functional channels have
as a characteristic feature a noncircular cross section with at
least one sharp-edged corner. The functional channels are advantageously
triangular in cross section with one, two or three curved boundary
sides, and with two or three sharp-edged corners. At least one of
the boundary sides of the functional channels is curved concavely
outwardly. It is thereby mainly the boundary side facing the adjacent
chip conveyor groove. A third boundary side can be curved convexly.
According to a preferred embodiment of the invention at least two
chip conveyor grooves are formed into the body of the drill, which
chip conveyor grooves are defined at their flanks by helically curved
lands having a partial-cylindrical outer surface defining flutes.
In each land there is arranged a preferably triangular functional
channel, which is noncircular in cross section. In the functional
channels having a triangular cross section there are provided an
outwardly convex outer boundary side, which is partially concentric
with respect to the partial cylindrical outer surface, and two inner
boundary sides, which follow the outer boundary side, are outwardly
at least partially concave, and meet in an acute-angled triangular
corner pointing toward the axis of the body of the drill. The two
inner boundary sides are thereby essentially parallel with respect
to the respectively adjacent flank portions of the chip conveyor
grooves.
According to a preferred embodiment of the invention the triangular
corners of two adjacent functional channels, which corners face
one another, are separated from one another by a joint, whereby
the joint extends essentially parallel with respect to the base
of the groove of two chip conveyor grooves, which are adjacent to
one another.
According to a further modification of the invention, the body
of the drill has three chip conveyor grooves, which are defined
at their flanks by helically curved lands. In addition, an axis-centrally
arranged functional channel, which is triangular in cross section,
is provided, the triangular corners of which taper pointedly or
acutely radially outwardly and end in each one joint.
The mentioned joints can be closed off by a welding or soldering
bridge.
At least one of the flanks of the chip conveyor grooves has advantageously
a boundary edge, which is sharp-edged toward the adjacent outer
surface of the flute.
A further preferred embodiment of the invention provides that the
functional channels end in the area of the shank-side outlet of
the chip conveyor grooves steplessly in an enlarged center supply
channel. At least one of the functional channels can be loaded with
a cooling lubricant through a center channel. The enlarged center
channel can in the case of the minimum lubricating technique also
be used as a depot for a lubricant. At least one of the functional
channels can be equipped with at least one wire-shaped, tubular
or cablelike insert preferably of metal, ceramic material and/or
plastic.
It is fundamentally possible to fill at least one of the functional
channels partially or completely with a filler, for example, designed
as a damping medium. The lands can furthermore have, in the area
of the partial-cylindrical outer surfaces, recesses for receiving
wear-resistant support elements or plankings projecting over the
partial-cylindrical outer surface. The chip conveyor grooves can
also have recesses extending in the longitudinal direction of the
grooves, for example, to receive reinforcing or vibration-hindering,
wear-resistant support elements.
The cutting head and/or the drill shank can be chiplessly formed,
for example, compressed, welded, soldered, glued or screwed to the
body of the drill. Using these manufacturing methods, no metal chips
are drawn from the body of the drill. The cutting head and the drill
shank can furthermore be connected to the body of the drill with
at least one tie rod penetrating through the body.
The invention will be discussed in greater detail hereinafter in
connection with the drawings, in which:
FIGS. 1a, 1b, and 1c illustrate a diagram of the method sequence
during the production of a body of a drill with two conveyor grooves
and two functional channels;
FIG. 2 is a diagrammatic illustration of the kneading tools used
for the production of the body of the drill;
FIGS. 3a and 3b are a diagrammatic side view and a local cross-sectional
illustration of the body of the drill produced with the method according
to FIGS. 1a to 1c;
FIG. 4 is a local cross-sectional view of a body of a drill with
three conveyor grooves, which body is produced by rotary kneading;
FIGS. 5a and 5b are each an exploded illustration of a drilling
tool consisting of the body of the drill, the cutting head and the
drill shank;
FIG. 5c is a diagrammatic illustration of the drilling tool according
to FIGS. 5a and 5b in an assembled state.
FIG. 6 is a side view of a rod-shaped, wire-shaped insert.
FIG. 7 is an exploded illustration of a drilling tool having a
tie rod joining the drill body and cutting head.
FIG. 8 is an exploded illustration of a drilling tool having recesses
to receive wear-resistant support elements.
DETAILED DESCRIPTION
The drilling tool illustrated in the drawings (FIG. 5c) consists
essentially of a body 10 a cutting head 12 arranged on the front
side on the body of the drill 10 and a rearward drill shank 14
to clamp the drilling tool in a not illustrated tool holder of a
machine tool. The body of the drill has two (FIGS. 3a and 3b) or
three (FIG. 4) conveyor grooves 16 which are defined at their flanks
by two helically curved lands 18. Furthermore two (FIGS. 3a and
3b) or three (FIG. 4) functioning channels 20 are provided in the
body of the drill 10 which are helically curved with the same curvature
as the lands 18 and extend along the lands 18 of the body of the
drill 10. The functioning channels 20 end steplessly at the shank-side
end in a common, axis-central supply channel 22. The exemplary embodiment
according to FIG. 4 has in addition an axis central functional channel
24 which extends along the drill axis 32 and is helically twisted
in its contour.
As can in particular be seen in FIGS. 3b and 4 the functional
channels 20 have a triangular cross section, the outer boundary
side 26 of which has an outwardly convex curvature, which is partially
concentrical with respect to the partial-cylindrical outer surface
28 of the respective lands 18 and the inner boundary sides 30.
The boundary sides follow the outer boundary side 26 inwardly, are
at least partially concavely curved, and meet acute-angled in a
triangular corner or edge 34 pointing toward the drill axis 32.
The two inner boundary sides 30 extend essentially parallel with
respect to the adjacent flank portions 31 of the chip conveyor grooves
16. The center functional channel 24 according to FIG. 4. has three
outwardly concave boundary sides 36 which at their acute-angled
boundary corners or edges 38 are directed toward the triangular
corners 34 of the functional channels 20 which lie on the outside.
A joint 40 extends between the triangular corners 34 facing one
another according to FIG. 3b or corners 34 and 38 according to FIG.
4. The joint extends parallel to the base of the groove of two adjacent
chip conveyor grooves 16 and preferably is closed off by a welding
or soldering bridge.
The functional channels 20 communicate with the outlet openings
42 in the cutting head 12. They can be loaded with cooling and lubricating
means through the supply channel 22. It is basically possible to
equip the functional channels 20 24 with a preferably wire-shaped,
tubular or cablelike insert 70 as shown in FIG. 6 for specific
purposes. The channels 20 24 can also be filled out with a filler
44 as in the case of the functional channel 24 according to FIG.
4.
In order to produce the body of the drill 10 a pipe-shaped blank
50 made out of a formable steel is fed in the direction of the arrow
54 to the kneading or hammering works 52 of a rotary kneading machine
or a rotary hammering machine. The kneading or hammering works 52
has several forming tools 56 57 looping around a partial circumference
of the blank 50 of which the forming tools 56 which are opposite
to one another, have a shaping contour 58 which forms the chip
conveyor grooves 16 of the body of the drill 10 and which is missing
in the two other forming tools 57 which are designed as support
tools. The conically designed inlet area 59 of the shaping contour
58 takes care on the one hand that the chip conveyor grooves 16
during passage of the blank 50 are slowly formed into the wall of
the blank. On the other hand, it determines with its conical contour
the shape of the rearward outlet area 61 of the chip conveyor grooves.
FIG. 2 shows in particular that the shaping contours 58 in the tools
56 are aligned inclined with respect to the passage direction 54
so that the blank during passage through the forming tools 56 57
can be rotated about its axis in the direction of the helix pitch
of the chip conveying groove 16 to be produced. The forming tools
56 carry out radial oscillation movements in direction of the double
arrows 60 which movements have a frequency of 100 to 2000 Hz and
load thereby the portions of the blank 50 which portions pass by
in the direction of the arrow 54 with shaping and calibrating forming
forces. Both the chip conveyor grooves 16 and also the functional
channels, which lie on the inside, are thereby formed. As can be
seen in FIGS. 1b and 1c, the forming is done via several passages--in
the illustrated exemplary embodiment in two--by the kneading or
hammering works 52 whereby the forming tools 56 57 are fed in
closer in steps. In order to avoid a tear from forming, the blank
50 can be tempered or annealed between two passages. Portions of
the inner surface of the blank rest during the last passage in the
area of the joint 40 and are there either cold-welded or soldered
with the help of an earlier supplied solder insert. The soldering
operation is done either by heat under the action of the forming
tools 56 or by subsequent heating of the finished body of the drill.
FIGS. 3a and 5a, 5b illustrate the finished body of the drill 10
which needs only to be connected to the cutting head 12 and the
drill shank 14. In order to produce the connection, the connection
partners (FIGS. 5a and 5b) are friction-welded, soldered, glued
or are screwed together by means of screws 62 (FIG. 5b). A connection
with the help of tie rods or a tie rod 72 shown in FIG. 7 can also
be utilized. The tie rod 72 can penetrate through the cutting head
12 the body of the drill 10 and the drill shank 14 and is anchored
under initial stress. The lands 18 can have, in the area of the
partial-cylindrical outer surfaces 28 recesses 76 for receiving
of wear-resistant support elements or plankings 78 projecting over
the partial-cylindrical outer surface. The chip conveyor grooves
16 can also have recesses extending in the longitudinal direction
of the grooves, for example, to receive reinforcing or vibration-hindering,
wear-resistant support elements.
In conclusion the following is to be stated: The invention relates
to a drilling tool for machine tools and a method for its production.
The drilling tool has at least one chip conveyor groove 16 and at
least one functional channel 20. In order to produce the body of
the drill 10 the wall of a tubular metal blank 50 is simultaneously
loaded or impinged upon by essentially radially oscillating shaping
or forming forces in several forming segments spread over the periphery,
moving in an axial direction along the surface of the blank, whereby
at least one chip conveyor groove 16 is formed or shaped and at
least one functional channel 20 24 is formed. When chip conveyor
grooves 16 are formed on at least two forming sections, which are
spaced apart in peripheral direction, into the wall of the blank
50 the portions of the wall in the area of two oppositely lying
chip conveyor grooves 16 abut one another sealingly defining at
least two functional channels 20 24 on their inner surface. The
joint 40 thus created can be closed off by cold welding or soldering. |