U.S. patent application number 17/033754 was filed with the patent office on 2021-04-01 for honing machine.
This patent application is currently assigned to KADIA Produktion GmbH + Co.. The applicant listed for this patent is KADIA Produktion GmbH + Co.. Invention is credited to Uwe Moos, Roland Regler.
Application Number | 20210094142 17/033754 |
Document ID | / |
Family ID | 1000005149755 |
Filed Date | 2021-04-01 |
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United States Patent
Application |
20210094142 |
Kind Code |
A1 |
Moos; Uwe ; et al. |
April 1, 2021 |
HONING MACHINE
Abstract
A honing machine for honing a bore in a workpiece comprises a
support structure fixed to the machine and at least one honing unit
which is mounted on the support structure and which has a spindle
unit (150) in which a spindle shaft (152) is rotatably mounted,
wherein the spindle shaft (152) is rotatable about a spindle axis
(155) by means of a rotary drive (450) and, at a tool-side end
(153), has a device for the fastening of an expandable honing tool.
The honing machine furthermore comprises a stroke drive for
generating a stroke movement of the spindle unit (150) and an
expansion drive (550) for expanding the honing tool, wherein the
expansion drive is coupled to an advancing rod (460) which runs in
the interior of the spindle shaft. The spindle unit (150) has a
spindle unit housing (310) which has a first housing portion
(310-1) for accommodating the rotary drive (450) and a second
housing portion (310-2) for accommodating the expansion drive
(550). The rotary drive (450) is accommodated in an exchangeable
first cartridge (400) and the expansion drive (550) is accommodated
in a second cartridge (500) which is exchangeable independently of
the first cartridge (400), wherein the first cartridge (400) is
introducible into the first housing portion (310-1) and the second
cartridge (500) is introducible into the second housing portion
(310-2).
Inventors: |
Moos; Uwe; (Dettingen an der
Erms, DE) ; Regler; Roland; (Georgensgmund,
DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
KADIA Produktion GmbH + Co. |
Nurtingen |
|
DE |
|
|
Assignee: |
KADIA Produktion GmbH + Co.
Nurtingen
DE
|
Family ID: |
1000005149755 |
Appl. No.: |
17/033754 |
Filed: |
September 26, 2020 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B24B 33/027
20130101 |
International
Class: |
B24B 33/02 20060101
B24B033/02 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 27, 2019 |
DE |
102019214873.5 |
Claims
1. A honing machine for honing a bore in a workpiece, comprising: a
support structure fixed to the machine; at least one honing unit
mounted on the support structure and which has a spindle unit in
which a spindle shaft is rotatably mounted, wherein the spindle
shaft is rotatable about a spindle axis by means of a rotary drive
and, at a tool-side end, has a device for the fastening of an
expandable honing tool, a stroke drive for generating a stroke
movement of the spindle unit; an expansion drive for expanding the
honing tool, wherein the expansion drive is coupled to an advancing
rod which runs in the interior of the spindle shaft; the spindle
unit comprising a spindle unit housing comprises a first housing
portion for accommodating the rotary drive and a second housing
portion for accommodating the expansion drive, wherein the rotary
drive is accommodated in an exchangeable first cartridge and the
expansion drive is accommodated in a second cartridge which is
exchangeable independently of the first cartridge, wherein the
first cartridge is introducible into the first housing portion and
the second cartridge is introducible into the second housing
portion.
2. The honing machine according to claim 1, wherein the spindle
unit housing is formed as a monocoque housing in which the first
housing portion is formed as a single piece with the second housing
portion.
3. The honing machine according to claim 1, wherein the first
cartridge and the second cartridge are introducible into the
spindle unit housing from opposite sides thereof.
4. The honing machine according to claim 1, wherein, on an inner
side of the first housing portion, there is formed at least one
first fitting surface which, in contact with at least one
corresponding first fitting surface on the first cartridge, effects
an alignment of the first cartridge in the first housing portion,
and/or wherein, on an inner side of the second housing portion,
there is formed at least one second fitting surface which, in
contact with at least one corresponding second fitting surface on
the second cartridge, effects an alignment of the second cartridge
in the second housing portion.
5. The honing machine according to claim 1, wherein, on the spindle
unit housing, there are formed axial stop surfaces for predefining
an axial position of the first cartridge in the first housing
portion and of the second cartridge in the second housing
portion.
6. The honing machine according to claim 1, wherein, on a side,
which is to face towards the second cartridge, of the first
cartridge, and on a side, which is to face towards the first
cartridge, of a housing portion of the spindle unit housing, there
are arranged corresponding connecting elements of at least one
plug-type connection for the transfer of at least one of fluid,
electrical power and electrical signals.
7. The honing machine according to claim 1, wherein the expansion
drive comprises has a torque motor.
8. The honing machine according to claim 1, wherein, in a cartridge
housing of the first cartridge, there are formed fluid channels for
conducting fluid.
9. The honing machine according to claim 8, wherein the fluid is
cooling fluid for the rotary drive.
Description
FIELD OF APPLICATION AND PRIOR ART
[0001] This application claims priority to German Patent
Application DE 10 2019 214 873.5 filed Sep. 27, 2019, the entirety
of which is incorporated herein by reference.
[0002] The invention relates to a honing machine for honing a bore
in a workpiece.
[0003] Honing is a cutting machining method using geometrically
undefined cutting edges, in the case of which a honing tool
performs a cutting movement composed of two components and there is
constant areal contact between one or more cutting material bodies,
for example honing strips, of the honing tool and the bore inner
surface to be machined. The kinematics of a honing tool are
characterized by a superposition of a rotational movement and a
stroke movement running in an axial direction of the bore.
Normally, an optional expansion movement is also provided, which
leads to a variation of the effective diameter of the honing
tool.
[0004] A one-off stroke movement of the honing tool within the
bore, composed of an advancement into the bore and a subsequent
retraction out of the bore, is referred to as "bobbing". A repeated
stroke movement within the bore, that is to say an advancement into
the bore, followed by a cyclic reciprocating movement within the
bore, and a subsequent retraction out of the bore at the end, is
referred to as "oscillating". In the case of oscillating honing
processes, an expansion movement is generally required, because the
effective diameter of the honing tool is actively varied during the
oscillation. Additionally, the wear of the cutting material body is
generally compensated by means of the expansion movement.
[0005] The kinematics of the honing tool generate a surface
structure with criss-crossing machining marks on the bore inner
surface. Surfaces finish-machined by honing can satisfy extremely
high demands with regard to dimensional and shape tolerances, and
in some cases have a special surface roughness and structure, such
as for example a plateau surface, which combines low wear owing to
a high material percentage contact area with the capability of
being able to readily receive an oil film for lubrication.
Therefore, many highly loaded sliding surfaces in engines or engine
components, for example cylinder barrels in engine blocks or bore
inner surfaces in housings of injection pumps, are machined by
honing.
[0006] A honing machine is a machine tool suitable for the honing
of bores in workplaces. Said honing machine has at least one honing
unit which is mounted on a support structure fixed to the machine,
for example a stand, a column or a frame. A honing unit comprises a
spindle unit in which a spindle shaft is rotatably mounted. The
spindle shaft is rotatable about its spindle axis by means of a
rotary drive and, at a tool-side end, has a device for the
fastening of a honing tool. To generate the stroke movement of the
spindle unit parallel to the spindle axis, a stroke drive is
provided. In generic honing machines, an expansion drive for
expanding the honing tool is furthermore provided. The expansion
drive is coupled to an advancing rod which runs in the interior of
the spindle shaft.
[0007] To optimize the economy and quality of honing processes, use
is increasingly made of highly dynamic direct drives for stroke and
rotation, which drives permit honing machining with high stroke
speeds (presently for example up to approximately 100 m/min) and
rotational speeds (presently for example up to approximately 5000
rpm).
[0008] Direct drives are known for the highly dynamic movement of
machine parts. Direct drives are distinguished by the potential for
permitting high speeds and accelerations of the machine axles
driven by them, with simultaneously virtually friction-free
generation of movement. DE 10 2016 200 295 A1 has described a
honing machine, the stroke drive of which is an electric linear
motor. The expansion drive is likewise an electric direct drive.
The spindle unit has a spindle unit housing which has a first
housing portion for accommodating the rotary drive and a second
housing portion, formed as a single piece with the first housing
portion, for accommodating the expansion drive.
[0009] The expansion drive and the rotary drive are subject to wear
in particular in the region of the ball bearings, such that, after
a few years of operation of the honing unit, it may be necessary
for the rotary drive, the expansion drive, or both assemblies, to
be overhauled. To reduce the downtime of the honing machine, a
second rotary drive or a second expansion drive is often procured
as a replacement part and installed in exchange for the worn
drive.
[0010] It may be the case that, with the exchange of the rotary
drive, it is additionally also necessary for the machine geometry
to be newly aligned. This is an expenditure of time and requires a
highly skilled technician. Although the expansion drive, with
further components of the expansion system, can be exchanged
independently of other components, the fastening of the expansion
means to the spindle motor however makes it necessary, in the event
of an exchange of the spindle motor, either for the expansion means
to firstly be dismounted, and mounted again at the end, or for the
entire assembly composed of spindle motor and screwed-on expansion
means to be removed jointly, which is disadvantageous owing to the
mass. In both cases, all connections of the expansion drive to the
machine (electrical lines, coolant, sensor arrangement) must be
dismounted, even if the expansion drive does not have to be
exchanged.
PROBLEM AND SOLUTION
[0011] The problem addressed by the invention is that of providing
a honing machine which is particularly easy to assemble for the
initial assembly process and which is particularly easy to repair
and maintain for any maintenance and repair work that is
required.
[0012] To solve this problem, the invention provides a honing
machine having the features of Claim 1. Advantageous refinements
are specified in the dependent claims. The wording of all the
claims is incorporated in the content of the description by
reference.
[0013] According to one formulation of the invention, a generic
honing machine is characterized in that the rotary drive is
accommodated in an exchangeable first cartridge and the expansion
drive is accommodated in a second cartridge which is exchangeable
independently of the first cartridge, wherein the first cartridge
is introducible into the first housing portion and the second
cartridge is introducible into the second housing portion.
[0014] Here, the expression "cartridge" stands for an exchangeable
assembly which combines, in one unit, all components that have to
be exchanged during an exchange process, and which has a dedicated
housing (cartridge housing). Accordingly, the first cartridge has a
first cartridge housing, in which, inter alia, the rotary drive is
accommodated, and the second cartridge has a second cartridge
housing, in which, inter alia, the expansion drive is accommodated.
The result is a modular construction of the spindle unit, in which
the mutual alignment of the first cartridge and of the second
cartridge and thus of the rotary drive and of the expansion drive
can be ensured by way of the installation into the commonly
utilized spindle unit housing. Said spindle unit housing serves as
a common geometrical reference for the installed components.
Additionally, it is also possible for the reference with respect to
the components of the linear guide of the stroke drive to be
established by means of the spindle unit housing, such that certain
alignment operations can be simplified or eliminated.
[0015] The accommodation of the rotary drive and of the expansion
drive in mutually independently exchangeable cartridges offers the
advantage inter alia that narrow tolerances can be adhered to very
easily from a manufacturing aspect. Owing to the narrow tolerances,
the renewed setting of the machine geometry after an exchange can
generally be omitted. In this way, repair and/or maintenance work
is considerably simplified and accelerated and can possibly be
performed by well-trained technicians, who need not be specialists
with regard to the alignment of the components. By means of the
arrangement of the first cartridge and of the second cartridge
within the common spindle unit housing, the rotary drive (spindle
motor) and the expansion drive can be exchanged independently of
one another.
[0016] The first cartridge and/or the second cartridge preferably
have a substantially rotationally symmetrical outer contour.
Mechanical orientation structures may be provided in order to
ensure that the cartridges can be installed into the spindle unit
housing only in one particular rotational position.
[0017] In preferred embodiments, it is provided that the spindle
unit housing is formed as a monocoque housing in which the first
housing portion is formed as a single piece with the second housing
portion. In this way, possible alignment-critical interfaces
between the housing portions are eliminated. A single-part spindle
unit housing may impart additional stability to the spindle unit
and offers an invariant geometrical reference of the housing
portions, and possibly of the cartridges accommodated therein, with
respect to one another. The spindle unit housing may possibly also
be assembled from multiple housing parts.
[0018] In principle, it is possible for the design to be configured
such that the first cartridge and the second cartridge can be
installed into the spindle unit housing from the same side.
However, in preferred embodiments, it is provided that the first
cartridge and the second cartridge are introducible into the
spindle unit housing from opposite sides thereof. In this way,
independent dismounting and mounting are made easier. In the case
of a vertically oriented spindle unit, the first cartridge, which
comprises the spindle motor, may be installed from below, whereas
the second cartridge, which comprises the expansion drive, is
inserted from above into the spindle unit housing.
[0019] In some embodiments, it is provided that, on an inner side
of the first housing portion, there is formed at least one first
fitting surface which, in contact with at least one corresponding
first fitting surface on the first cartridge, effects a positioning
and alignment of the first cartridge in the first housing portion,
and, alternatively or in addition, on an inner side of the second
housing portion, there is formed at least one second fitting
surface which, in contact with at least one corresponding second
fitting surface on the second cartridge, effects a positioning and
alignment of the second cartridge in the second housing portion.
The position and the alignment may be defined by fitting diameters
situated on the outer diameter of the cartridges. In some
embodiments, it is considered to be particularly advantageous for
an internally situated fit to be configured with a smaller diameter
than an external fit provided on a flange, such that, during
mounting and dismounting, the respective fitting surfaces come into
contact with one another only when the respective cartridge has
been almost fully inserted into the spindle unit housing, not
already at the start of the insertion into the spindle unit
housing.
[0020] Furthermore, on the spindle unit housing, there may be
formed axial stop surfaces for predefining an axial position of the
first cartridge in the first housing portion and of the second
cartridge in the second housing portion. In some embodiments, it is
provided that, on the cartridges, there are provided outwardly
projecting flange portions which abut against associated end
surfaces of the spindle unit housing when the corresponding
cartridge is inserted into said spindle unit housing and the
desired axial installation position has been attained. The
respective axial fastening, that is to say the fixing of the axial
position of the respective cartridge in relation to the spindle
unit housing, can thus be realized by means of a flange with axial
screws.
[0021] In many designs, it is relatively easily possible for the
expansion drive or the second cartridge to be directly contacted
from the outside and thus for the media required for operation
(electrical power, possibly an exchange of electrical signals for
control and for transmission of encoder signals, fluid media) to be
conducted in and conducted out. Since, however, in the case of the
first cartridge, contacting from the side of the connection for the
honing tool is not possible or is possible only under adverse
constraints, the first cartridge should as far as possible also be
contacted through the spindle unit housing. For this purpose, in
some embodiments, it is provided that connections for possibly
present rotary encoders, the electrical connections for the feed of
electrical power for the motor coil and/or connections for fluids
(coolant for dissipating the motor waste heat, coolant feed line
and coolant return line to the machining location, possibly sealing
air) should be arranged preferably at that side of the first
cartridge which is to face towards the second cartridge.
[0022] In some embodiments, connection problems are resolved in a
particularly convenient manner in that, on a side, which is to face
towards the second cartridge, of the first cartridge, and on a
side, which is to face towards the first cartridge, of a housing
portion of the spindle unit housing, there are arranged
corresponding connecting elements of at least one plug-type
connection for the transfer of liquid or gaseous fluid, electrical
power and/or electrical signals. Owing to the configuration as a
plug-type connection, the required connection is produced
automatically during the assembly of the components, such that no
separate assembly steps are required for producing electrical
and/or fluidic connections. Owing to the configuration as a
plug-type connection, an exchange of the first cartridge is
possible much more quickly and easily than if multiple lines had to
be individually disconnected and reconnected.
[0023] The cartridge concept can be implemented with different
drive types of the rotary drive and/or of the expansion drive. In
one refinement, as an expansion drive, a torque motor is provided
which is installed directly into the second cartridge housing. In
this way, the expansion drive can be configured to be extremely
short and thus also lightweight. The torque motor may be coupled to
a rotary encoder, preferably to a high-resolution absolute encoder
with multiturn capability. The rotating part of the torque motor
may drive a threaded spindle in order to generate, from the
rotational movement, a linear movement which then acts on the
advancing rod running in the interior of the spindle shaft.
[0024] The torque motor is an example of an electric direct drive.
As an alternative to the torque motor, the drive may also be some
other electric direct drive, for example a plunger coil motor,
which requires no threaded spindle or the like to convert the
movement direction. It is also possible to use a servomotor as a
rotary drive.
[0025] To further facilitate assembly and maintenance and repair
work, it is provided in some embodiments that fluid channels for
conducting fluid, in particular cooling fluid for the rotary drive,
are formed in the cartridge housing of the first cartridge. In this
way, the cartridge housing of the first cartridge can be directly
cooled, and the heat can be dissipated from the region of the
rotary drive via the cartridge housing. In this way, a cooling
device on the rotary drive itself can possibly be omitted. This
yields the possibility of providing a compact construction of the
rotary drive, which can then be dismounted jointly with the first
cartridge without the need for a servicing technician to detach
hose connections.
[0026] Alternatively or in addition, it may be provided that fluid
channels for conducting fluid are formed in the spindle unit
housing. It is for example possible for fluid channels to be
provided for conducting cooling fluid for the rotary drive. In this
way, the spindle unit housing can be directly cooled, and the heat
can be dissipated for example from the region of the rotary drive
via the spindle unit housing. In this way, it may be possible for a
cooling device and/or coolant channels on the first cartridge
and/or on the rotary drive itself to be omitted. Alternatively or
in addition, fluid channels may be provided for conducting fluid to
the honing tool and back from the honing tool.
BRIEF DESCRIPTION OF THE DRAWINGS
[0027] Further advantages and aspects of the invention will emerge
from the claims and from the following description of preferred
exemplary embodiments of the invention, which are explained below
on the basis of the figures:
[0028] FIG. 1 shows an oblique perspective view of a honing machine
according to an exemplary embodiment;
[0029] FIG. 2 shows a vertical section through a honing unit
arranged on the support structure of the honing machine and
components of a rotary table transport system;
[0030] FIG. 3 shows a section along the y-z plane through a setting
unit of an alignment system according to an exemplary
embodiment;
[0031] FIG. 4 shows a section parallel to the x-y plane through the
setting unit from FIG. 3;
[0032] FIG. 5 shows an exploded illustration of the setting unit of
FIGS. 3 and 4;
[0033] FIG. 6 shows the replacement of components of an expansion
system in which the expansion drive is arranged in an exchangeable
cartridge;
[0034] FIG. 7 shows the replacement of the spindle shaft and of
other components of the spindle unit, wherein the rotary drive is
arranged in an exchangeable cartridge;
[0035] FIG. 8 shows an oblique perspective view of the cartridge
containing the rotary drive, which cartridge, on its top side, has
plug connectors for plug-type connections for the electrical and
fluidic connection of components of the cartridge; and
[0036] FIGS. 9A to 9D show special features of the available stroke
length and stroke positions of the embodiment.
DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS
[0037] FIG. 1 shows an oblique perspective view of a honing machine
100 according to an exemplary embodiment. FIG. 2 shows a vertical
section through a honing unit arranged on the support structure of
the honing machine and components of a rotary table transport
system. In the configuration shown, the honing machine has only a
single honing unit. A second support structure with a second honing
unit for machining the same workpieces may be provided.
[0038] The honing machine 100 has a substantially rectangular
machine base 110 with a frame and a base plate which is or should
be oriented horizontally in the case of a fully set-up honing
machine. The rectangular base plate is somewhat longer in the first
direction (longitudinal direction) running parallel to the y axis
of the machine coordinate system MKS than in the second direction
(transverse direction) which is perpendicular thereto and which
runs parallel to the x axis of the machine coordinate system. Close
to the rear side 114 of the machine base, in the vicinity of one of
the longitudinal edges, there is arranged a vertical stand 120,
which is fixedly screwed to the machine base. The vertical stand
serves as a support structure 120 for a honing unit 130, which is
mounted on the support structure in the region of the front side of
the latter.
[0039] A major constituent part of the honing unit is a spindle
unit 150 in which a spindle shaft 152 is rotatably mounted. To
drive the spindle shaft, there is integrated a rotary drive or
spindle motor which is integrated into the spindle unit and which
can drive the spindle shaft about the spindle axis 155, that is to
say about the axis of rotation of the spindle shaft 152, with a
predefined rotational speed profile. The spindle shaft 152 has, at
a tool-side end 153, which is also referred to as spindle nose, a
device (tool receptacle) for the fastening of a honing tool
190.
[0040] The spindle unit 150 is mounted on the top side or front
side of a carriage plate 165. The carriage plate is supported by a
carriage box 160 which serves as the main support of the honing
unit. Between the main support 160, which is formed by the carriage
box, and the carriage plate 165 or the spindle unit supported
thereby, there is provided a linear guide system (not visible in
the illustrations) for guiding a linear stroke movement of the
spindle unit 150 relative to the main support 160. In the example,
the stroke drive has an electric linear motor with a primary part
and a secondary part which are movable relative to one another
parallel to the longitudinal direction of the longitudinal guide
system (ideally also parallel to the spindle axis 155).
[0041] In the example, the primary part, which is operated with an
electrical current, is attached to the carriage plate, or to the
spindle unit 150 which is likewise operated with current, whereas a
series of permanent magnets is arranged within the main support
160. A reversed arrangement is also possible.
[0042] The linear guide system has guide rails which are attached
to the main support 160. The corresponding guide shoes are arranged
on the bottom side of the carriage plate 165. There are also
embodiments in which the guide shoes, which slide on the guide
rails, are fastened to individual fastening surfaces of the spindle
unit, without the interposition of a carriage plate which is common
to the guide shoes.
[0043] The honing machine 100 is equipped with a workpiece
transport system 180 which has a rotary table or a rotary indexing
table. In the case of the illustrated rotary table transport
system, a horizontally oriented table panel 184 is provided which,
by means of a rotary drive arranged under the table panel, can be
rotated in predefined angular steps about an axis of rotation 185
which is oriented nominally vertically (parallel to the z direction
of the machine coordinate system). On a pitch circle about the axis
of rotation 185, there are provided multiple (in the example, six)
workpiece receptacles 182 for receiving in each case one workpiece
W. During transportation, the table panel rotates through a
particular angle (in this case 60.degree.) about the axis of
rotation 185, which is positioned fixedly in space, in order to
successively arrange in each case one workpiece W in a machining
position under the honing unit 130 such that the spindle axis 155
corresponds as closely as possible to the bore axis in the
workpiece W. Ideally, all workpiece receptacles are mounted so as
to be as far as possible equally spaced apart from the axis of
rotation 185 and as far as possible with a uniform circumferential
spacing to one another. If multiple honing units or multiple honing
stations are served by the rotary table transport system 180, then
all honing units must be as far as possible aligned such that, in
any transport position, there is as small as possible a spacing
between the actual axis of rotation of the spindle motor and the
bore axis in the tool. This means that all honing units must be
correspondingly aligned in the honing machine.
[0044] The honing unit 130 is fastened by means of two fastening
units 210-1, 210-2 to the front side of the stand or of the support
structure 120. Here, the fastening units constitute a mechanical
connection between the stand 120 (support structure 120), which is
fixed with respect to the machine, and the base support 160 of the
honing unit 130. The vertical spacing 212, measured in the z
direction, between the effective centres of the fastening units
210-1, 210-2 amounts, in the example, to more than 30%, in
particular more than 40% and/or less than 90% or less than 80% of
the length, measured in the vertical direction, of the main support
160. The fastening units are not arranged at the outer ends of the
main support 160 but rather are offset inward. What is particularly
advantageous is an arrangement such that the fastening units are
positioned such that the guide shoes, which are situated on the
carriage plate which supports the spindle unit, have as small a
spacing as possible to the fastening units when the spindle unit is
situated in a stroke position intended for the machining process.
Here, it is possible in particular for the dynamic forces that
arise during an oscillating stroke movement to be particularly
readily accommodated.
[0045] The fastening units 210-1 and 210-2 simultaneously function
as first setting unit 210-1 and second setting unit 210-2 of an
alignment system 200, the components of which are arranged at least
partially between the support structure 120 and the main support
160. By means of the alignment system 200, it is possible both for
the position of the spindle axis 155 to be adjusted in continuously
variable and reversible fashion along two mutually perpendicular
axes of translation, and for the setting of the orientation
(angular attitude) of the spindle axes to be adjusted in
continuously variable and reversible fashion in relation to two
mutually perpendicular axes of rotation. In this way, it is
possible for the spindle unit as a whole to be aligned such that
its axis (spindle axis 155) is aligned as closely as possible with
the axis of the bore to be machined.
[0046] Each of the setting units 210-1, 210-2 offers exactly two
translational setting degrees of freedom. In the case of a first
setting degree of freedom, the structural height, measured parallel
to the first direction (y direction), of the setting unit can be
varied in continuously variable and reversible fashion within
certain limits, such that the spacing 214, measured parallel to the
first direction, between the support structure 120 and the main
support 160 of the honing unit at the location of the fastening
unit can be varied. First setting elements are provided for this
purpose. In the case of the second setting degree of freedom, it is
possible for those components of the setting unit which are fixedly
connected to the main support 160 of the honing unit 130 to be
displaced in continuously variable and reversible fashion, parallel
to the second direction (x direction), relative to those components
which are fixedly connected to the support structure 120. Second
setting elements are provided for this purpose. There are
components which belong both to the first and to the second setting
elements and which thus have a dual function (for example a wedge
element discussed in more detail further below).
[0047] These two translational setting degrees of freedom, together
with the fact that the two setting units 210-1, 210-2 are arranged
with a vertical spacing 212 to one another (measured along the z
direction or the third direction), make it possible for the
position of the spindle axis 155 to be set along two mutually
perpendicular axes of translation (parallel to the first direction
and parallel to the second direction) and, independently of this,
also for the orientation of the spindle axis 155 in relation to two
mutually perpendicular axes of rotation (in each case parallel to
the first direction and to the second direction) to be set in
continuously variable and reversible fashion.
[0048] If, for example, both setting units 210-1, 210-2 are
adjusted in terms of their effective structural height such that
the spacing 214, measured parallel to the first direction, between
support structure 120 and main support 160 is changed by the same
magnitude, the result is a change in the position of the spindle
axis 155 by parallel displacement in a y-z plane, or a translation
of the spindle axis 155 in the first direction. This corresponds to
purely a change in position without a change in the
orientation.
[0049] If no change in spacing, or a different change in spacing
than that at the second setting unit 210-2, is set at the first
setting unit 210-1, this results in a change in inclination of the
spindle axis 155 within the y-z plane, which leads to a rotation of
the spindle axis about a virtual axis of rotation which runs
parallel to the second direction (x direction) perpendicular to the
y-z plane. The result is thus a change in the orientation.
[0050] If a displacement parallel to the second direction (x
direction) by the same displacement travel is set at the first
setting unit 210-1 and at the second setting unit 210-2, the result
is a parallel displacement of the spindle axis in an x-z plane or a
translation of the spindle axis 155 in the second direction. This
corresponds to purely a change in position without a change in the
orientation.
[0051] If displacement travels of unequal length are set at the
first setting unit 210-1 and at the second setting unit 210-2, this
results in an adjustment of the inclination of the spindle axis in
an x-z plane, which corresponds to a rotation about a virtual axis
of rotation which runs parallel to the first direction.
[0052] The spatial attitude of the virtual axes of rotation that
possibly arise is not fixed but rather varies in a manner dependent
on the ratios of the variations performed at the two setting
units.
[0053] Details of the construction of the first setting unit 210-1
or of the first fastening unit 210-1 of the alignment system 200
will now be discussed in more detail below with additional
reference to FIGS. 3 to 5. Here, FIG. 3 shows a section along the
y-z plane through the setting unit, FIG. 4 shows a section parallel
to the x-y plane, and FIG. 5 shows an exploded illustration of the
first setting unit 210-1. The second setting unit 210-2 may be of
identical or virtually identical construction.
[0054] The setting unit 210-1 comprises a base element 220 which is
composed of multiple components and which is designed for being
mounted fixedly on the support structure 120 of the honing machine
or on an adapter unit which is connected fixedly to the support
structure. Furthermore, a wedge element 230 is provided which has a
planar first wedge surface 231 facing towards the base element 220
and has a planar second wedge surface 232 which, in the assembled
state, faces toward the main support 160. The wedge surfaces 231,
232 of the relatively flat wedge enclose a wedge angle 233 of
approximately 5.degree. to 6.degree.. In the assembled state, the
planar first wedge surface 231 lies areally against a planar
sliding surface 221, facing towards said first wedge surface, of
the base element 220. A relative displacement of the wedge element
230 relative to said sliding surface 221 of the base element along
a displacement direction 238 running parallel to the x direction
(second direction) is provided by the construction, whereas
relative movements in other directions are prevented by the
construction. The actuating devices which are provided for
actuating this relative displacement and which serve for displacing
the wedge element 230 in the displacement direction and for
positioning the wedge element in a target position will be
discussed in more detail further below.
[0055] The base element 220 includes a spherical socket 222, which
serves as a basis for the fastening unit and is provided for being
fixedly screwed to the support structure of the honing machine at
the fastening position provided for it. In some embodiments, an
adapter unit with suitable assembly interfaces is also interposed
between the spherical socket and the support structure. A
cylindrical pin may be used for the orientation of the spherical
socket 222 in terms of attitude on the support structure 120 or on
an adapter provided for connecting to the support structure. Said
cylindrical pin can define the rotational position of the spherical
socket in a fitting bore of the support structure or of an
adapter.
[0056] On the side facing towards the wedge element, there is
formed a spherically curved sliding surface 223. In the assembled
state, a spherical disc 224 lies in the spherical socket 222. Said
spherical disc has, on the side facing towards the spherical
socket, a convex spherical sliding surface 225 corresponding with
the sliding surface 223, and has, on the side facing towards the
wedge element, the planar sliding surface 221. A free rotation of
the spherical disc 224 in the spherical socket 222 is prevented by
virtue of the spherical socket having two cylindrical pins 228
which run in a groove in the spherical disc 224. Thus, only a
limited rotation about an axis of rotation running parallel to the
second direction is possible.
[0057] During the assembly process, the wedge element 230 is placed
onto the spherical disc 224. Said wedge element may also be
displaced laterally in the displacement direction (parallel to the
x direction) in order to be able to set the structural height,
measured parallel to the y direction, of the setting element in
continuously variable and reversible fashion. Firstly, the angle of
the wedge element 230 should be shallow enough that it lies in the
range of self-locking. Here, this means that a change in load on
the wedge element should not trigger any lateral displacement of
the wedge element. Secondly, however, the angle of the wedge
element should also be steep enough that a sufficient range of
adjustment in the height of the wedge element is present with the
available lateral displacement travel of the wedge element 230. In
the exemplary embodiment, the wedge angle 223 is dimensioned such
that there is an integer ratio between the lateral displacement of
the wedge element and the resulting change in height of the
fastening unit or of the setting unit. A wedge with a corresponding
ratio of 1:10 has proven highly suitable, such that a displacement
by 1 mm causes a change in height by 0.1 mm.
[0058] Two tension anchors 229 are provided for facilitating the
handling of the components during the assembly process. These each
exert a slight pressure on the wedge element 230 via a helical
spring, such that said wedge element is supported on the spherical
disc 224 and thus prevents the wedge element from lifting off the
spherical disc during the assembly process.
[0059] In the fixedly installed spherical socket 222, there is
fixedly installed a substantially cuboidal holding block 226. In
the holding block, there is seated a bearing bolt 227 on which the
main support 160 can be supported during the mounting of the honing
unit 130 onto the fastening unit 210-1, in order, during the
assembly process, to compensate for the mass of the honing unit
with respect to the Earth's gravitational force. The bearing bolt
227 has a circular outer contour at its side facing towards the
honing unit. The main support 160 has, on its side facing towards
the fastening unit, a rectangular pocket or recess 162 for
receiving the support bolt, which in the received state ideally
forms linear contact (or, in the case of relatively great angles of
inclination, punctiform contact) with the rectangular pocket, such
that no constraint is imparted even in the event of inclination of
the honing unit.
[0060] On the upper fastening unit 210-1, the support bolt 227 is
fitted relatively tightly in said pocket on the main support 160,
in order to fix the position of the honing unit in the honing
machine relatively accurately already during the assembly process.
On the lower fastening unit 210-2, the pocket on the main support
160 of the honing unit is somewhat larger, such that no constraint
is imparted to the honing unit here either.
[0061] In the wedge element 230, on opposite sides of the polygonal
cutout provided for the passage of the holding block 226, there are
provided threaded bores which are oriented substantially parallel
to the second direction. Into the threaded bores, there are screwed
setting screws 240-1, 240-2 which serve as actuating elements of an
actuating device for displacing the wedge element 230 in the
displacement device 238. By means of these setting screws, the
wedge element can be displaced against the holding block 226 (which
is attached fixedly with respect to the machine) in the
displacement direction 238. The height adjustment of the fastening
element and thus the spacing adjustment (in the y direction)
between support structure and main support of the honing unit at
location of the setting unit is effected by displacement of the
wedge element. When the desired target position has been attained,
the wedge element automatically holds this position owing to
self-locking. The wedge element can however be additionally fixed
in this position by tightening of the setting screws which act
against one another.
[0062] On the main body 160, at the location provided for the
attachment of the fastening unit or setting unit 210-1, there is
formed a planar oblique surface 164 which in the assembled state
interacts, as a sliding surface, with the second wedge surface 232.
In the main support 160 of the honing unit, there are furthermore
formed threaded bores which run parallel to the x direction and in
which setting screws 250-1, 250-2 are seated. Said setting screws
are likewise supported on the holding block 226 (which is installed
fixedly with respect to the machine). A displacement of the main
support 160 of the honing unit relative to the support structure
120, which is fixed with respect to the machine, parallel to the
displacement direction 238 is possible by actuation of the setting
screws 250-1, 250-2. Here, the planar second wedge surface 232 and
the oppositely situated planar oblique surface 164 on the main
support slide on one another. Since this is associated with a
minimal change in spacing in the y direction, the setting screws
240-1, 240-2 should also be adjusted to the same extent for the
purposes of compensation.
[0063] A configuration such that each rotation of the setting screw
results in a fixed extent of the displacement is advantageous. For
example, in the case of a thread pitch of 1 mm, one full rotation
of the setting screw 250-2 results in a displacement of 1 mm. By
re-measuring the positions of the parts with respect to one
another, the respectively set position can be read off, and the
adjustment travel that is still required can be estimated.
[0064] The basic setting of the fastening units 210-1, 210-2 is the
theoretical centre, such that, in this position, in the absence of
all manufacturing tolerances of the honing machine, the axis of the
spindle motor, that is to say the spindle axis 155, would run
exactly in alignment with the bore axis in the workpiece.
Proceeding from this central position, both the height of the
setting units parallel to the first direction (y direction) and
also the lateral offset by relative displacement parallel to the
second direction (x direction) can be reversibly set independently
of one another by means of the setting screws 240-1, 240-2 and
250-1, 250-2 respectively. A lateral displacement parallel to the x
direction arises here from the setting screws 250-1, 250-2 in the
main support. The setting of the height of the fastening unit in
the y direction arises from the setting screws or forcing-off
screws 240-1, 240-2 in the wedge element 230.
[0065] In order to vary the position of the honing unit relative to
the bore axis in the workpiece, the upper setting unit 210-1 and
the lower setting unit 210-2 are adjusted in each case in the same
direction by the same setting travel. In order to adjust the
angular position of the unit, the upper setting unit and the lower
setting unit are adjusted in opposite directions and/or to
different extents. In the case of the fastening units being set in
opposite directions and/or to different extents, an angular offset
between those wedge surfaces of the wedge elements which lie on the
spherical segments can occur owing to the different heights of the
two setting units. This angular offset can be compensated by means
of small compensation movements of the spherical discs in the
spherical sockets. Thus, the spherical bearings which are
integrated into the fastening units 210-1, 210-2 and which have the
complementary curved sliding surfaces serve as an angle
compensation device for automatically compensating angular offsets,
and stresses possibly caused as a result, in the case of adverse
setting conditions of the setting units. In the example, the radius
of curvature of the spherical sliding surfaces 223, 225 is selected
such that (in the case of the wedge element being set into its
central position) the sphere central point lies on the axis of
rotation of the spindle motor, that is to say on the spindle axis
155. Thus, possible compensation movements do not have an effect on
the position and orientation of the spindle axis.
[0066] A method for setting the machine geometry with alignment of
the spindle axis in relation to the bore axis of the bore that is
to be honed may for example progress as follows.
[0067] Firstly, the fastening units 210-1, 210-2 which serve as
setting units are fastened at their intended positions to the front
side of the support structure by means of screws. Here, the wedge
elements and the spherical discs are each brought into a central
position.
[0068] The honing unit is subsequently fitted by being mounted at
the top and bottom on the bearing bolts 227. The main support 160
of the honing unit 130 is then brought into a central position.
[0069] For an alignment operation, as long as possible a
cylindrical geometry with reference to the workpiece receptacle or
to the transport system should be provided on sides of the
workpiece receptacle. For example, a master cylinder may be
installed as an alignment aid at the location of a workpiece
receptacle of the rotary table transport system. The cylindrical
bore in the master cylinder thus represents the bore axis in the
workpiece and produces the reference to the transport system. This
step may be performed before or after the fitting of the honing
unit on the support structure.
[0070] Thereafter, the parallelism of the axis of rotation of the
spindle motor, that is to say the parallelism of the spindle axis
with respect to the central longitudinal axis of the master
cylinder, can be set for example by setting of the setting units in
opposite directions and/or to different extents. Here, it is
preferably firstly the case that the lateral setting (parallel to
the displacement direction) is performed by means of the setting
screws in the main support, and then the frontal setting is
performed by displacement of the wedge elements.
[0071] Thereafter, the master cylinder can be dismounted, in order
to measure a possible position offset of the spindle axis with
respect to the setpoint position directly at those bores of the
transport system in which the workpiece receptacles will later be
installed.
[0072] If these measurements yield that a position offset is still
required, then the position of the axis of rotation of the spindle
motor with respect to the bore axis of the workpiece is set by
adjustment of the setting elements in the same directions to equal
extents. Here, too, it is preferably the case that firstly the
lateral position (position in the x direction) is set and
subsequently the frontal position (position along the first
direction or y direction) is set.
[0073] When the desired target position and target orientation have
been attained with sufficient accuracy, then the setting screws of
the setting units are tightened without further displacement of the
components thereby actuated, in order to fix the relative positions
assumed.
[0074] The support structure may, as shown, be for example a
vertical stand, which possibly supports only a single honing unit.
A honing machine may have two or more such stands. The support
structure may also be a column, on the periphery of which multiple
holding units may be mounted in a circumferentially offset manner
(cf. DE 20 2011 003 069 U1). Instead of the direct mounting of the
fastening units on the support structure, as illustrated, an
indirect fastening by means of an adapter provided for connecting
to the support structure is also possible.
[0075] Special features of the construction of a spindle unit 300
which is provided in some embodiments will now be described on the
basis of FIGS. 6 to 8. The spindle unit 150 of the exemplary
embodiments described above may be of identical construction to the
spindle unit 300 described below. It is however also possible for
the spindle unit 150 to have a different construction than the
spindle unit 300 described here. Aside from the spindle unit, the
illustrated components are denoted by the same reference
designations as in the preceding examples.
[0076] The spindle unit 300 has a modular construction. The spindle
unit housing 310 is constructed as a single-piece component and is
also referred to here as a monocoque housing. The substantially
tubular component, which is open at both sides, has a first housing
portion 310-1, which accommodates the rotary drive 450, and a
second housing portion 310-2, which is formed in one piece with
said first housing portion and which has a smaller inner diameter
than the first housing portion 310-1 and which is provided for
accommodating the expansion drive 550.
[0077] The rotary drive 450 is arranged in an exchangeable first
cartridge 400 and is mounted on the interior of the substantially
rotationally symmetrical cartridge sleeve 410 of the first
cartridge 400. The expansion drive 550 is arranged in a second
cartridge 500 and is mounted within the cartridge housing 510 of
the second cartridge.
[0078] The first cartridge 400 is insertable into the first housing
portion 310-1 from below. Independently of this, the second
cartridge 500 with the expansion drive is insertable from above
into the second housing portion 310-2. The expansion drive is
coupled to an axially movable advancing rod 460 which, during the
assembly of the spindle unit, is introduced into an inner passage
bore of the spindle shaft 152 and, during the operation of the
honing machine, acts on an axially displaceable expansion cone
which is arranged in the interior of the honing tool.
[0079] FIG. 6 shows a configuration in which the first cartridge
400 (with rotary drive 450) has been installed into the spindle
unit housing 310 so as to be ready for operation, whereas the
second cartridge 500 with the expansion drive 550 has been removed
in an upward direction. FIG. 7 shows a configuration in which the
second cartridge 500 with expansion drive 550 has been introduced
into its associated second housing portion 310-2, whereas the first
cartridge 400 with the rotary drive 450 has been removed from the
spindle unit housing in a downward direction.
[0080] A comparison of FIGS. 6 and 7 shows that the removal of the
two cartridges or the installation thereof is possible at opposite
sides without a large structural space requirement at the sides,
because, for the removal or for the installation of the second
cartridge 500, the carriage 165 which is displaceable on the main
support 160 can be moved downwards, whereas, for the removal or for
the installation of the first cartridge 400, the carriage 165 with
the spindle unit housing 310 can move upwards, such that, in a
downward direction, there remains sufficient free space for the
removal of the first cartridge 400 without the risk of a collision
with the transport system or with workpiece holding devices.
[0081] The single-piece spindle unit housing 310, which may be
produced for example from a torsionally resistant aluminium alloy
or from a fibre composite material, serves as a mechanical
reference for the mutual coaxial alignment of the two carriages
400, 500 and of the components contained therein and also as a
mechanical reference for establishing the correct alignment of said
components of the spindle unit 300 in relation to the linear guide
system of the stroke drive.
[0082] To ensure that each of the cartridges is installed in the
correct alignment and in the correct axial position in relation to
the associated housing portion of the spindle unit housing,
corresponding fitting surfaces are formed on the outer sides of the
respective cartridges and the inner sides of the associated housing
portions. In FIG. 7, the centring fitting surfaces of the first
housing portion 310-1 for receiving the first cartridge 400 can be
clearly seen. Directly adjoining the bottom end side 315 of the
spindle unit housing 310, a rotationally symmetrical lower fitting
surface 312 is formed on the inner side of said spindle unit
housing. A rotationally symmetrical upper fitting surface 313 is
formed with a spacing in an upward direction, that is to say in the
interior of the first housing portion 310-1.
[0083] An outwardly projecting flange 415 is formed in the lower
third on the cartridge housing 410 of the first cartridge 400. The
upwardly pointing flange surface of said flange serves as an axial
stop surface for an abutment against the end side 315 of the
spindle unit housing and thus defines the axial position of the
installed cartridge. Directly above the flange 415, there is
situated a wide rotationally symmetrical fitting surface 416 which
fits with the fitting surface 312. Above this, with a spacing,
there is situated a further fitting surface 417, which fits with
the upper fitting surface 313. The internally situated fit between
the fitting surfaces 313 and 417 is formed with a smaller diameter
than the external fit with the fitting surfaces 416 and 312 in the
vicinity of the flange 415. It can thus be achieved that, during
the mounting process, the respective fitting surfaces come into
contact with one another only when the first cartridge 400 has been
almost fully inserted into the spindle unit housing or the
associated housing portion, and not already at the start of the
insertion into the spindle unit housing.
[0084] A corresponding solution is also provided for the
installation of the second cartridge 500 in the second housing
portion 310-2. There, too, there are two fitting surface pairs,
which are situated so as to be spaced apart from one another, and,
on the widened head of the second cartridge 500, a stop surface 515
which, during the axial insertion of the second cartridge 500,
abuts against the upper end side 316 of the spindle unit housing
310 and thus defines the axial position of the second cartridge 500
in the spindle unit housing. Thus, the correct alignment and axial
position of the cartridges is set without further alignment work
once the insertion of the cartridges has been completed during the
mounting on the spindle unit housing.
[0085] One particular challenge consists in providing, in the
spindle unit 300, suitable electrical and fluidic connections of
the components installed in the first cartridge 400. Whereas the
components of the second cartridge 500 which accommodates the
expansion drive 550 can be contacted relatively easily directly
from above by means of suitable connectors, contacting of the
components (for example rotary drive) provided in the first
cartridge 400 from below, that is to say from the side at which the
honing tool is coupled on, is not possible or is possible only with
restrictions.
[0086] In the exemplary embodiment, connection problems for the
internal components of the first cartridge 400 are resolved by
virtue of connecting elements of suitable plug-type connections
being attached to the upper side of the first cartridge 400, that
is to say to the inner side which is to face towards the second
cartridge 500. Said connecting elements cooperate with
corresponding connecting elements of a plug-type connection on a
housing portion 318 of the spindle unit housing 310 at the stepped
transition from the relatively large diameter in the first housing
portion 310-1 to the relatively small diameter at the second
housing portion 310-2.
[0087] In the exemplary embodiment of FIG. 8, there are
automatically sealing male plug connector components of fluid
connecting elements 470 for the introduction or discharge of liquid
or gaseous fluids. Two of the fluid plug connectors serve for the
feed and discharge of cooling liquid for the cooling of components
arranged within the first cartridge 400, in particular of the
rotary drive. These plug-type connectors are connected to coolant
channels 472 which run in the interior of the wall of the cartridge
housing 410 of the first cartridge and which are indicated here
merely by dashed lines. Coolant channels may for example run in
helical fashion within the cartridge housing. It is also possible
to construct a channel network with partially axially running
coolant channel portions and transverse connections. Two further
fluid connecting elements may serve for the feed and discharge of
cooling lubricant to the honing tool and from the honing tool.
Gaseous fluids may also be connected. For example, a connector may
be provided for conducting sealing air through the cartridge
housing 410 of the first cartridge 400 to an outlet on the tool
side of the first cartridge.
[0088] The electrical plug contacts 475 serve for the supply of
electrical power to the rotary drive 450 and the transmission of
information relating to the rotary drive, for example from
temperature sensors. The electrical connections 480 serve for the
transmission of signals from encoders installed in the first
cartridge 400, for example of a rotary encoder of the rotary drive,
for the purposes of controlling the honing machine. The rotary
encoder may be composed of a static and a rotating part, wherein
the static part functions as a measuring head 485.
[0089] The associated plug sockets are attached to the downwardly
pointing side of the housing portion 318 at the stepped transition
between the relatively large inner diameter of the first housing
portion 310-1 and the relatively small inner diameter of the second
housing portion 310-2. The electrical and fluid connections are
automatically produced in the final phase of the insertion, when
the first cartridge 400 is inserted, in the correct rotational
position, into the associated first housing portion 310-1. To
ensure that the first cartridge can be introduced, and inserted as
far as the stop, only in a single rotational position, a
corresponding structure is provided.
[0090] Further special features of the machine concept of the
exemplary embodiment will now be discussed in conjunction with
FIGS. 9A to 9D. The honing machine may be used for the honing of
workpieces of very different workpiece heights and bore lengths
without the need for the honing machine to be converted for this
purpose. FIGS. 9A and 9B show the machining of a workpiece W1, the
workpiece height of which corresponds to the maximum height WHO of
a workpiece height range taken into consideration in the design.
The honing machine can thus machine workpieces up to this workpiece
height.
[0091] FIGS. 9C and 9D show the machining of workpieces W2 which
have a smaller workpiece height and which have only a relatively
short bore for machining.
[0092] A relatively long honing tool 190-1 is accordingly required
for the machining of the tall workpiece W1, whereas a relatively
short honing tool 190-2 can be used for the machining of the short
bore in the relatively short workpiece W2, which makes it possible
to realize small concentricity errors and thus high levels of
machining quality.
[0093] In the design of the honing unit 130, attention is paid
inter alia to an optimum axial mounting position of the main
support 160 or of the carriage box 160 on the support structure
120. Here, the main support 160 is attached to the support
structure 120 such that an end 166 close to the workpiece, that is
to say the bottom edge 166 of the carriage box or of the main
support 160, lies with a spacing above the upper boundary WHO,
facing towards the spindle unit, of the workpiece height range.
[0094] It is thus possible, during rotation of the rotary table or
of the table panel 184 thereof about the rotary table axis 185, for
even the tallest workpieces W1 to move through below the main
support 160 without collision, if the spindle unit 150 has been
retracted sufficiently far upwards. In this regard, FIG. 9A shows a
situation in which the spindle unit 150 has been moved into its
upper end position. In the example, said spindle unit is designed
such that, even in the case of the longest honing tool 190-1 being
used, the tip thereof, which faces towards the workpiece, extends
at most as far as the level (illustrated by means of a dashed line)
of the lower edge 166 of the main support, but no further in the
direction of the workpiece. In this way, firstly, free transport of
the workpieces is ensured in the case of a retracted spindle unit
(FIG. 9A), and secondly, the stroke length of the linear movement
of the spindle unit is so great that, when the spindle unit has
been moved down, the long honing tool 190-1 can machine the bore
over its entire length with an oscillating stroke. In this regard,
FIG. 9B shows the spindle unit at its bottom dead centre, close to
the workpiece, of the oscillating stroke movement.
[0095] It is important here that the spindle unit 150 can also be
moved further downwards in the direction of the workpiece if
required, as will be discussed in more detail on the basis of FIG.
9D.
[0096] It can be seen from FIG. 9C that the workpiece-facing end,
or the bottom edge 166, of the main support is arranged far above
the movement path of the relatively short workpieces W2, such that
the workpieces can be transported around the rotary table axis 185
into their respective machining position below the spindle unit
without colliding with the main support.
[0097] In the case of a short honing tool 190-2 being used for
machining the short bore of a short workpiece, the spindle unit 150
must be moved relatively far downwards or in the direction of the
workpieces. Here, FIG. 9D shows a position of the spindle unit
close to the bottom dead centre of the oscillating movement of the
holding tool 190-2 in the bore of the short workpiece W2. It can be
clearly seen in this illustration that, in this position, close to
the workpiece, of the stroke movement of the spindle unit 150, the
tool-side end 153 of the spindle shaft 152, that is to say the
spindle nose 153 with the device for receiving the tool, is moved
downwards beyond the lower end 166 of the main support and thus
lies closer to the workpiece height range than that end 166 of the
main support which is close to the workpiece. In the working
position of FIG. 9D, it can also be clearly seen that the tool-side
end 153 of the spindle shaft projects in a downward direction, or
in the direction of the workpieces, beyond the workpiece-side end
of the carriage plate 165 to the workpiece side. The projecting
length 167, that is to say the length by which the spindle nose 153
projects beyond the workpiece-side end of the main support 160, may
for example amount to 10% or more or 25% or more of the total
length of the spindle unit between spindle nose and upper end of
the expansion device.
[0098] Furthermore, owing to the use of electric direct drives for
the rotary drive and the expansion drive, the spindle unit 150 is
so short in an axial direction, that is to say parallel to the
spindle axis, that, even in the stroke position furthest remote
from the workpiece (FIG. 9A), the upper end of the spindle unit 150
does not project beyond the upper end of the main support 160. The
machine roof 105 can thus be attached directly above the upper end
of the main support 160, whereby an enclosure of the honing machine
which is compact even in a height direction is made possible.
[0099] Tests performed by the inventor with regard to favourable
dimensioning proportions have found that, for many practically
relevant applications or workpieces, the workpiece height range may
lie in the range from 250 mm to 500 mm, in particular in the range
from 250 mm to 400 mm. The upper boundary WHO of the workpiece
height range may thus lie for example 250 mm to 500 mm above a
reference plane, wherein the reference plane is the plane on which
the workpiece holding devices are mounted (that is to say for
example the top side of the table panel). The bottom edge 166 of
the main support may lie one or a few mm above this upper boundary.
Expedient stroke lengths may lie for example in the range from 450
mm to 700 mm, in particular in the range from 500 mm to 650 mm.
Expedient stroke lengths may lie for example in the range from 150
mm to 900 mm, in particular in the range from 180 mm to 850 mm
(likewise in relation to the reference plane measured above).
Expedient lengths of the main support may lie for example in the
range from 1000 mm to 1500 mm, in particular in the range from 1100
mm to 1400 mm. Expedient axial lengths of the spindle unit
(measured from the spindle nose to the top side of the spindle unit
housing) may lie for example in the range from 500 mm to 900 mm, in
particular in the range from 600 mm to 800 mm. Typical tool lengths
may lie for example in the tool length range from 100 mm to 150 mm
(for the relatively short honing tools) up to 350 to 600 mm (for
the relatively long honing tools).
[0100] Considering the structurally possible projecting length 167
of the spindle nose beyond the bottom edge 166 of the main support,
this may lie for example in the range from 20% to 40% of the stroke
length, in particular in the range from 25% to 35% of the stroke
length. The upper boundary of the workpiece height range may for
example amount to 50% to 75% of the stroke length, in particular
60% to 70%. The stroke length may for example lie in the range from
70% to 90% of the length of the spindle unit. Deviations from these
dimensions and dimension proportions are self-evidently possible
and may be expedient in particular cases.
* * * * *