Machine tools abstract
A tool head, in particular a fine adjustment head for use in machine-tools,
may be coupled to a rotary machine spindle (26) and has a slide
(16) that may be adjusted transversely to the axis (12) of the base
body and is provided with a projecting tool-receiving part (14)
on its front face. A measurement arrangement (18) is provided for
directly measuring the adjustment path of the slide (16) in relation
to the base body (10). The tool head further has an adjustment motor
(20) that acts on the slide (16) in the direction of adjustment
and an external current supply arrangement (22) for electronic components
integrated into the tool head and for the adjustment motor (20).
In order to obtain a compact design with high adjustment precision,
the adjustment motor (20) is arranged with its cylindrical housing
(45) in a recess (46) of the base body (10) that extends transversely
to the direction of adjustment of the slide (45) and to the axis
of the base body. The recess (46) extends across the axis (12) of
the base body and the driven shaft (48) of the motor extends parallel
to the recess (46).
Machine tools claims
The embodiments of the invention in which an exclusive property
or privilege is claimed are defined as follows:
1. A tool head for use in machine tools, comprising a body defining
a body axis, a tool shank connected to the body which extends axially
beyond the body and is adapted to be coupled to a rotating machine
spindle of a machine tool, at least one slide positioned in the
body and adapted to be adjusted transversely with respect to the
body axis in an adjusting direction, a tool carrier connected to
the slide extending beyond an end face of the body, a measuring
device for directly measuring a position of the slide in relation
to the body, measuring electronics arranged in the body and connected
to the measuring device, an adjusting motor arranged in the body
and acting on the slide to adjust the slide in the adjusting direction,
the adjusting motor having an output shaft, a power supply device
for supplying power to the measuring electronics and the adjusting
motor, and a transverse recess positioned in the body and adapted
to receive the adjusting motor therein, the transverse recess being
aligned transversely to the body axis and intersecting the body
axis, the output shaft of the adjusting motor being aligned parallel
with respect to the transverse recess.
2. The tool head as claimed in claim 1 wherein the transverse
recess for receiving the adjusting motor is arranged in the body
transversely with respect to the adjusting direction of the slide.
3. The tool head as claimed in claim 1 wherein the adjusting motor
has a substantially cylindrical motor housing clamped on the body
in an axially resilient manner, the motor housing being positioned
in the transverse recess.
4. A tool head for use in machine tools, comprising a body defining
a body axis, a tool shank connected to the body which extends axially
beyond the body and is adapted to be coupled to a rotating machine
spindle of a machine tool, at least one slide positioned in the
body and has an adjusting mechanism for adjusting the slide transversely
with respect to the body axis in an adjusting direction, a tool
carrier connected to the slide extending beyond an end face of the
body, a measuring device for directly measuring a position of the
slide in relation to the body, measuring electronics arranged in
the body and connected to the measuring device, an adjusting motor
arranged in the body and acting on the slide to adjust the slide
in the adjusting direction, the adjusting motor having an output
shaft, a power supply device for the measuring electronics and the
adjusting motor, a transverse recess positioned in the body and
adapted to receive the adjusting motor therein, the transverse recess
being aligned transversely to the body axis and intersecting the
body axis, the output shaft of the adjusting motor being aligned
parallel with respect to the transverse recess, the adjusting motor
having a motor housing, and an output gearwheel being supported
by the output shaft, the output gear wheel extending in a cup-like
manner over an output end of the motor housing and is coupled to
the adjusting mechanism of the slide.
5. The tool head according to claim 4 wherein the output gearwheel
is mounted axially and radially with an inner side thereof on a
part of the body which extends axially and in the circumferential
direction over an output end of the motor housing and has a central
bore for passing therethrough the output shaft.
6. The tool head as claimed in claim 4 wherein a cup-shaped cover
part is rigidly connected to the body, and wherein a bearing journal
mounts the output gearwheel in the cup-shaped cover part.
7. The tool head as claimed in claim 4 wherein the output gearwheel
has a radially outward facing toothed rim concentrically embracing
the motor housing in the vicinity of an output end of the motor
housing.
8. The tool head as claimed in claim 4 wherein the adjusting mechanism
has a threaded spindle, a sliding block, a counterpiece, and a drive
pinion, the threaded spindle being mounted eccentrically in the
body and having oblique teeth supporting the sliding block, the
counterpiece having complementary oblique teeth and being connected
rigidly to the slide, the threaded spindle supporting the drive
pinion meshing with a part of the output gearwheel in a region thereof
extending over the motor housing in a cup-like manner.
9. The tool head as claimed in claim 8 wherein a cover part covers
an end of the body and the body has a radially continuous guide
groove for the slide without any end limitations, and wherein a
spacer is arranged on the side of the sliding block between the
body and the cover part.
10. The tool head as claimed claim 4 wherein the output shaft
of the adjusting motor is designed as a polygon which engages in
a polygonal socket of the output gearwheel, the polygonal socket
of the output gearwheel having a greater axial length than the output
shaft and being accessible from outside with a corresponding polygonal
tool.
11. The tool head as claimed in claim 1 wherein the body is surrounded
annularly by a metallic casing, and has window openings for receiving
an infrared transceiver in each window opening, the window openings
being arranged at angular internals from one another.
12. The tool head as claimed in claim 11 wherein a clamping cover
clamps the adjusting motor on the body at an end opposite the output
shaft, the clamping cover having a radially outward extending attachment
for engagement in a corresponding recess of the casing.
13. The tool head as claimed in claim 1 wherein the measuring
device has a plunger coil fixed to the body, and a bar-shaped magnet
armature fixed to the slide and reaching through the plunger coil
in the adjusting direction of the slide.
14. The tool head as claimed in claim 13 wherein the slide has
a pocket-like recess, and wherein the plunger coil is arranged in
a coil housing which is fixed to the body and engages in the pocket-like
recess of the slides, and the bar-shaped magnet armature extends
through the pocket-like recess and the plunger coil in the adjusting
direction of the slide.
15. The tool head as claimed in claim 14 wherein the coil housing
has laterally overhanging assembly lugs for fastening onto the body.
16. The tool head as claimed in claim 14 wherein the coil housing
has a closed coil space.
17. The tool head as claimed in claim 15 wherein the coil housing
has a recess which is arranged in a region between two of the assembly
lugs, the recess partially embracing the motor housing around the
circumference thereof.
18. The tool head as claimed in claim 14 wherein an adjusting
holder is threadedly bored into the body and is aligned in the adjusting
direction of the slide, and wherein the magnet armature is fastened
by one end thereof on the adjusting holder, the magnet armature
extending from an end face of the adjusting holder.
19. The tool head as claimed in claim 18 wherein the slide has
a linear guide, and wherein a guide pin is positioned at an end
of the magnet armature at the end opposite the adjusting holder
engaging in the linear guide within the slide.
20. The tool head as claimed in claim 18 wherein a lock screw
fixes the adjusting holder on the slide, the lock screw being accessible
from outside in a predetermined sliding position of the slide.
21. The tool head as claimed in claim 1 wherein a cover part is
connected to the end face of the body, the end face of the body
has a slot therein, the cover part has an annular groove therein,
an elastomeric sealing ring being arranged in the annular groove,
the tool carrier passes through the slot, a washer is supported
outside the slot on the tool carrier and is sealed off radially
with respect to the tool carrier, the washer being moved along with
the slide and being pressed resiliently against the elastomeric
sealing ring, and a gap which is substantially constant over the
circumference of the washer being positioned between the washer
and the cover part and has a width of 5 to 20 .mu.m.
22. The tool head as claimed in claim 21 wherein the washer has
means for setting the width of the gap.
23. The tool head as claimed in claim 21 wherein a spring ring
is arranged in a circumferential groove on the tool carrier for
pressing the washer against the sealing ring.
Machine tools description
FIELD OF THE INVENTION
The invention relates to a tool head for use in machine tools.
More specifically, the invention is directed to a tool head having
a basic body, a tool shank which extends axially beyond the basic
body and can be coupled to a rotating machine spindle, having at
least one slide which can be adjusted transversely with respect
to the basic body axis and has a tool carrier extending beyond the
end face, having a measuring device for directly measuring the adjusting
path of the slide in relation to the basic body, having measuring
electronics arranged in the basic body and connected to the measuring
device, having an adjusting motor, preferably electric, arranged
in the basic body and acting in the adjusting direction on the slide,
and having a power supply device for the measuring electronics and,
if appropriate, the adjusting motor.
BACKGROUND OF THE INVENTION
To be able to set the slide and the cutting tool carried by its
tool carrier accurately, it is necessary to measure exactly the
adjusting path of the slide. For this purpose, it is known (WO91/03345)
to measure the adjusting path of the slide in relation to the basic
body in a direct way, for example by an optical or capacitive path
measuring system, and to evaluate the measured results externally
by means of a wireless, preferably optoelectronic, data exchange.
Furthermore, it is also known from this document to provide in the
basic body an adjusting motor which acts in the adjusting direction
on the slide and can likewise be actuated by means of a remote control.
The arrangement of the adjusting motor in the tool head has not
as yet been satisfactorily achieved. It presents difficulties when
one considers that the rotating motions of the tool head and of
the rotary motor can be superposed in an undesirable way, in particular
during accelerating and braking operations, and that a compact design
is desired, in particular in the case of small precision adjustment
heads.
Against this background, the invention is based on the object of
developing a tool head of the type specified at the beginning which
ensures a compact design and trouble free operation.
The way in which this is achieved according to the invention is
based on the idea that an isolation of the rotary motion of the
adjusting motor and of the tool head can be accomplished in a compact
design by the adjusting motor being arranged along with its substantially
cylindrical motor housing in a transverse recess of the basic body,
aligned transversely with respect to the basic body axis and intersecting
the basic body axis, with the motor output shaft aligned parallel
with respect to the transverse recess. A further improvement in
this respect is accomplished if the transverse recess for receiving
the adjusting motor is arranged in the basic body transversely with
respect to the adjusting direction of the slide, it also being of
advantage here if the path measuring system intersects the basic
body axis in the adjusting direction of the slide.
To reduce the undesirable starting current peaks when starting
the adjusting motor, the motor housing is clamped on the basic body
in a resilient manner, axially and preferably also in the turning
direction.
A particularly compact design is advantageously accomplished by
the motor output shaft bearing an output gearwheel which reaches
in a cup-like manner over the output end of the motor housing, is
coupled to an adjusting mechanism of the slide and is advantageously
mounted, preferably axially and radially, with its cup inner side
on a part of the basic body which reaches axially and radially over
the output end of the motor housing and has a central bore for the
passing through of the output shaft. This achieves the effect that
the radially outward facing teeth of the output gearwheel concentrically
embrace the motor housing in the vicinity of the output end. On
its cup outer side, the output gearwheel is additionally mounted
in a preferably cup-shaped cover part, rigidly connected to the
basic body.
An advantageous refinement of the invention provides an adjusting
mechanism for the slide which has a spindle, mounted eccentrically
in the basic body and bearing a sliding block with oblique toothing,
and a counterpiece, provided with complementary oblique toothing
and connected rigidly to the slide, which spindle bears a drive
pinion meshing with the output gearwheel in the region of the part
reaching over the adjusting motor in a cup-like manner.
The output shaft of the adjusting motor is advantageously designed
as a polygon, preferably as a hexagon, which engages in a polygonal
socket of the output gearwheel, the polygonal socket of the output
gearwheel having a greater axial extent than the output shaft, so
that it is accessible from the outside with a corresponding polygonal
tool for manual adjustment.
Externally, the basic body is expediently surrounded by a preferably
metallic casing, in which there are arranged at angular intervals
from one another window openings for receiving an infrared transceiver
in each case. The rotary driving of the casing takes place by the
adjusting motor being adapted such that it can be clamped on the
basic body at the end opposite the output side by a clamping cover
which has a radially outward extending attachment for engagement
in a corresponding recess of the casing.
A preferred alternative or refinement of the invention provides
that the measuring device has a plunger coil, arranged in a coil
housing which is fixed to the basic body and engages in a pocket-like
recess of the slide, and a bar-shaped magnet armature, fixed to
the slide and reaching through the pocket-like recess and the plunger
coil in the sliding direction of the slide and transversely with
respect to the motor housing axis. The measuring system operating
on the plunger coil principle has the advantage over the known capacitive
measuring system that an absolute path measurement is possible without
data loss if the power is disconnected and that installation is
less demanding in terms of the tolerances to be maintained.
To permit an adjustment of the path measuring system, the magnet
armature is fastened by its one end, overhanging the end face, expediently
on an adjusting holder turned into a threaded bore aligned in the
sliding direction of the slide, whereas it bears at its end opposite
the adjusting holder a guide pin, engaging in a linear guide within
the slide. To be able to arrest the magnet armature, once adjustment
has taken place, in its zero position on the slide, the adjusting
holder can be fixed on the slide by a lock screw which is accessible
from the outside in a predetermined sliding position of the slide.
The coil housing, preferably consisting of an antimagnetic material,
has laterally overhanging assembly lugs for fastening on the basic
body. It expediently has a round, closed coil space for receiving
the plunger coil, and is provided on the side facing the motor,
preferably in the region between the two assembly lugs, with a recess
partially embracing the motor housing around its circumference.
The resulting mutual interlocking between coil housing and motor
housing permits a compact design of the tool head.
To seal off the interior of the tool head in a fluid-tight manner
and nevertheless ensure low-friction sliding of the slide with respect
to the basic body, it is proposed according to an advantageous refinement
of the invention that the slide with its tool carrier passes through
a slot on the end face of the basic body and, outside the slot,
bears a washer which is sealed off radially with respect to the
slide, is moved along with the slide and can be pressed resiliently
against an elastomeric sealing ring, which is arranged in an annular
groove on the end face of the basic body and is preferably designed
as a square ring, such that between the washer and the basic body
there remains a gap which is substantially constant over the circumference
of the washer and has a width of 5 to 20 .mu.m. The wall thickness
of the washer can expediently be adapted by material removal on
its face facing the basic body, thereby setting the predetermined
gap width, while the pressing of the washer against the sealing
ring may be performed by a spring ring arranged in a circumferential
groove on the slide.
To be able to grind the sliding surface of the slide throughout
in the basic body and nevertheless ensure stable fitting of the
cover, it is proposed according to a further advantageous refinement
of the invention that the basic body has a radially continuous sliding
surface for the slide without any end limitations, and that there
is arranged on the side of the sliding block a spacer between the
basic body and the cover part. The spacer also ensures that the
retroactive forces from the oblique toothing of the adjusting mechanism
for the slide can be absorbed and introduced into the basic body.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention is explained in more detail below with reference
to an exemplary embodiment represented diagrammatically in the drawings,
in which:
FIG. 1 shows a side view of a precision turning head with adjusting
mechanism, remote control and external power supply, clamped in
a machine spindle;
FIG. 2 shows a longitudinal section through the precision turning
head according to FIG. 1 with tool shank;
FIG. 3 shows a longitudinal section through the precision turning
head turned through 90.degree. with respect to FIG. 2;
FIG. 4 shows a section along the section line IV--IV of FIG. 3;
FIG. 5 shows an enlarged detail from FIG. 2 with sectioned length
measuring device;
FIG. 6 shows a section along the section line VI--VI of FIG. 5.
DETAILED DESCRIPTION
The precision turning head represented in the drawing essentially
comprises a basic body 10 a slide 16 which is adjustable in relation
to the basic body 10 transversely with respect to the axis of rotation
12 of the precision turning head and bears a tool carrier 14 for
a cutting tool, a measuring device 18 for directly measuring the
adjusting path of the slide 16 in relation to the basic body 10
an electric adjusting motor 20 acting on the slide in the adjusting
direction, a power supply device 22 and a tool shank 24 which extends
axially beyond the basic body 10 and can be coupled to a machine
spindle 26 of a machine tool 28.
The slide 16 is arranged in the basic body 10 in a continuous guide
groove 30 which is aligned transversely with respect to the basic
body axis 12 has no end limitations and is bounded from the outside
by means of a cover part 32 rigidly connected to the basic body
10 at the end by means of spacers 81. The slide 16 passes with its
tool carrier 14 through a slot 34 of the cover part 32 to the outside
and, outside the slot 34 bears a washer 38 which is sealed off
radially with respect to the tool carrier 14 by an annular sealing
member 36; the tool carrier 14 has a circumferential groove 41 receiving
a spring ring 40 thereon; and the washer 38 moves along with the
slide and can be pressed with the aid of the spring ring 40 resiliently
against a square ring 44 which is arranged in an annular groove
42 of the cover part, such that between the washer 38 and the cover
part 32 there remains a gap which is substantially constant over
the circumference of the washer 38 and has a width of 10 .mu.m.
This measure avoids the metallic washer 38 rubbing on the metallic
cover part 32 during sliding of the slide.
The adjusting motor 20 has a substantially cylindrical motor housing
45 which is arranged in a transverse recess of the basic body 10
running transversely with respect to the sliding direction of the
slide 16 and the basic body axis 12 and intersecting the basic body
axis 12. The axially overhanging output shaft 48 is designed as
a hexagon. It bears an output gearwheel 50 of a cup-shaped design,
the hexagonal socket 52 of which is longer than the output shaft
48 so that, when the screw plug 54 is removed, a corresponding
hexagonal tool can be inserted from the outside into the hexagonal
socket 52 for manual adjustment of the output gearwheel. The output
gearwheel 50 reaches with its inwardly facing, externally toothed
casing part 56 over the output end of the motor housing 45 and is
radially supported there on the outside by means of a sliding bearing
60 on a sleeve attachment 58 receiving the relevant housing end.
Furthermore, the output gearwheel 50 is axially mounted with its
cup inner side on the sleeve attachment 58 by means of a rolling
bearing 62 whereas it is mounted on the cup outer side with its
hollow pin 63 having the hexagonal socket 52 in a rotary bearing,
designed as rolling bearing 64 of a cup-shaped cover part 66 fixed
to the basic body. On its side opposite the output side, the adjusting
motor 20 is axially clamped by a clamping cover 68 and an elastomeric
ring 70 against the output-side sleeve attachment 58 the torsional
securement of the motor housing 45 taking place by means of the
eccentric pins 72 arranged on the output side. The axially resilient
clamping with torsional resilience allows smooth starting of the
motor, as a result of which starting current peaks can be reduced.
In consideration of the centrifugal force acting on the motor, this
applies in particular whenever the center of gravity of the adjusting
motor is radially shifted with respect to the axis of rotation 12
of the basic body 10 toward the resilient ring 70.
The output gearwheel 50 is used for driving an eccentrically arranged
adjusting mechanism for the slide which has a drive pinion 76 meshing
with the toothed rim 74 of the output gearwheel 50 and a threaded
spindle 77 rigidly connected to the said pinion. Guided on the
threaded spindle is a sliding block 78 with oblique toothing 80
which meshes with complementary oblique toothing 82 of a counterpiece
84 arranged on the slide 16.
The measuring device 18 has a plunger coil 86 fixed to the basic
body, and a bar-shaped magnet armature 88 fixed to the slide and
reaching into the plunger coil 86 in the sliding direction. The
plunger coil 86 is arranged essentially centrally in the basic body
10 in a coil housing 90 which is fixed to the basic body and, from
the motor side, reaches together with the plunger coil into a pocket-like
recess 92 of the slide. The magnet armature 88 is fastened by its
one end, overhanging at the end face, on an adjusting holder 94
turned into a threaded bore 95 aligned in the sliding direction
of the slide 16 whereas it bears at its end opposite the adjusting
holder 94 a guide pin 98 engaging in a linear guide (bore) 96 within
the slide 16. The adjusting holder 94 can be fixed on the slide
16 by a lock screw 100 which is accessible from the outside in a
predetermined position of the slide. The coil housing is provided
with laterally overhanging assembly lugs 102 and has on its side
opposite the coil space 104 a recess 106 which is arranged in the
region between the two assembly lugs 102 and partially embraces
the motor housing 45 around its circumference.
The basic body 10 is embraced around its circumference by a casing
ring 108 of metal or plastic, in which there are arranged distributed
at equal angular intervals over the circumference windows 110 for
infrared transceivers 112. The transceivers provide the wireless
data exchange between the tool head and an external, computer-aided
remote control device. The data exchange, for example for adjusting
purposes, may also take place galvanically via the interface 114.
The tool shank 24 for the connection to the machine spindle 26
is axially fastened by a single central screw 116 in a shank holder
117 on the basic body 10. The eccentrically arranged fitting pins
118 in this case ensure the torsional securement and torque transmission.
On the side of the tool shank 24 there is additionally arranged
an annular coil housing 120 which is fastened on the basic body
together with the tool shank 24 by means of the radially overhanging
collar 122 of the latter, using the central screw 116. The torsional
securement of the coil housing 120 takes place by means of the driver
bolts 124 which are designed as countersunk screws and engage with
their shank in corresponding bores of the basic body.
In the coil housing 120 there is a secondary coil, which is embedded
in a mechanically loadable casting compound of plastic or synthetic
resin and has associated stabilization electronics, which constitute
part of an inductive transmission link of the power supply device
22 and ensure the power supply to the adjusting motor 20 and to
the electronic circuits contained in the tool head. In principle,
it is possible to use the induction link also for bidirectional
data exchange, in that the data signals are modulated onto the induction
current in both directions, if appropriate.
The primary coil of the inductive transmission link is arranged
in a coil housing 126 on the stator side, which housing reaches
into the free interspace between the end face of the machine spindle
26 and the end face of the coil housing 120 on the tool head side,
radially outside the tool shank 24. For setting the air gap between
the primary coil and the secondary coil, the coil housing 126 on
the stator side is arranged on a holder 128 fixed to the stator,
adjustably both in its distance from the coil housing 120 on the
tool head side and in its rotational position about an axis parallel
to the axis of rotation 12. The holder 128 with the coil housing
126 may also be fitted subsequently onto an existing machine tool.
The coil housing 126 on the stator side extends only over a partial
circumference of the tool shank and leaves the predominant part
of the shank circumference free for the access of a tool gripper
130 for automatic tool changing. During tool changing, the tool
head is grasped at the gripper channel 132 by the tool gripper 130
from the side opposite the coil housing 126 on the stator side and,
with the tool coupling released, is displaced axially in relation
to the machine spindle 26. The coupling of the tool head to the
machine spindle 26 in this case takes place by means of a clamping
mechanism 136 which can be activated on the machine side by means
of the draw bar 134 and engages from the machine side in the cavity
138 of the tool shank 24 and couples the tool head to the machine
spindle 26 establishing end face bracing and radial bracing.
To sum up, the following may be stated: the invention relates to
a tool head, in particular a precision adjustment head, for use
in machine tools. The tool head can be coupled to a rotating machine
spindle 26 has a slide 16 which can be adjusted transversely with
respect to the basic body axis 12 and has a tool carrier 14 extending
beyond the end face, a measuring device 18 for directly measuring
the adjusting path of the slide 16 in relation to the basic body
10 an adjusting motor 20 acting in the adjusting direction on the
slide 16 and an external power supply device 22 for electronics,
integrated in the tool head, and the adjusting motor 20. To ensure
a compact design along with high adjusting accuracy, the adjusting
motor 20 is arranged along with its cylindrical motor housing 45
in a transverse recess 46 of the basic body 10 aligned transversely
with respect to the adjusting direction of the slide 16 and transversely
with respect to the basic body axis 12 and intersecting the basic
body axis 12 with the motor output shaft 48 aligned parallel with
respect to the transverse recess 46. |