U.S. patent application number 15/808102 was filed with the patent office on 2018-03-29 for lubricating system comprising a spindle and an aerosol dispenser.
This patent application is currently assigned to KNOLL MASCHINENBAU GMBH. The applicant listed for this patent is KNOLL MASCHINENBAU GMBH. Invention is credited to Talip AYGUN, Yasar AYGUN.
Application Number | 20180085876 15/808102 |
Document ID | / |
Family ID | 55971003 |
Filed Date | 2018-03-29 |
United States Patent
Application |
20180085876 |
Kind Code |
A1 |
AYGUN; Talip ; et
al. |
March 29, 2018 |
LUBRICATING SYSTEM COMPRISING A SPINDLE AND AN AEROSOL
DISPENSER
Abstract
A lubricating system with an aerosol generator, a spindle, a
tool clamper arranged on the spindle, and a rotary feedthrough
arranged on the side of the spindle lying opposite the tool
clamper, a duct runs through the tool clamper, the spindle and the
rotary feedthrough. A separate aerosol generator feeds aerosol into
an aerosol line to a tool via the rotary feedthrough, spindle and
tool holder to transport lubricant particles and/or coolant
particles inside the spindle or motor spindle. A spindle tube is
arranged in the duct and is mounted non-rotatably on a non-rotating
portion of the rotary feedthrough and extends at least through a
portion of the spindle in the direction of the tool clamper, and
the aerosol generator is connected to the spindle tube, such that
aerosol is guided through the spindle tube in the direction of the
tool clamper and/or a tool clamped by the tool clamper.
Inventors: |
AYGUN; Talip; (Krauchenwies,
DE) ; AYGUN; Yasar; (Krauchenwies, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
KNOLL MASCHINENBAU GMBH |
Bad Saulgau |
|
DE |
|
|
Assignee: |
KNOLL MASCHINENBAU GMBH
Bad Saulgau
DE
|
Family ID: |
55971003 |
Appl. No.: |
15/808102 |
Filed: |
November 9, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
PCT/EP2016/060826 |
May 13, 2016 |
|
|
|
15808102 |
|
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|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B23Q 11/1015 20130101;
B23Q 11/1076 20130101; B23Q 11/0046 20130101 |
International
Class: |
B23Q 11/10 20060101
B23Q011/10 |
Foreign Application Data
Date |
Code |
Application Number |
May 13, 2015 |
DE |
20 2015102 484.3 |
Claims
1. A lubricating system, in particular a single-duct minimum
quantity lubricating system, with an aerosol generator, a spindle,
a tool clamper arranged on the spindle, and a rotary feedthrough
arranged on the side of the spindle lying opposite the tool
clamper, wherein a duct runs through the tool clamper, the spindle
and the rotary feedthrough, wherein a separate aerosol generator is
provided in order to generate aerosol therein and to feed the
aerosol into an aerosol line and convey the aerosol from there to a
tool via the rotary feedthrough, the spindle and the tool clamper,
wherein a spindle tube is arranged in the duct and is non-rotatably
mounted on a non-rotating portion of the rotary feedthrough and
extends at least through a portion of the spindle in the direction
of the tool clamper, and wherein the aerosol generator is connected
to the spindle tube, such that aerosol is guided through the
spindle tube in the direction of the tool clamper and/or the tool
clamped by the tool clamper.
2. The lubricating system as claimed in claim 1, wherein the
spindle tube is mounted rotatably on the tool clamper.
3. The lubricating system as claimed in claim 1, wherein the
spindle tube is arranged at least partially inside an aerosol duct
for the conveying/guiding of aerosol, such that aerosol is
conveyed/guided both on/along an inner wall of the spindle tube and
also partially on/along an outer wall of the spindle tube.
4. The lubricating system as claimed in claim 1, wherein the
spindle tube has at least one spindle tube opening for aerosol to
flow through.
5. The lubricating system as claimed in claim 3, wherein the
aerosol duct is designed as a rotatable duct tube.
6. The lubricating system as claimed in claim 5, wherein at least
one rotary bearing is arranged between the spindle tube and the
rotatable duct tube.
7. The lubricating system as claimed in claim 6, wherein the at
least one rotary bearing is designed as a slide bearing.
8. The lubricating system as claimed in claim 5, wherein the
rotatable duct tube is designed as a pull rod for operating the
tool clamper.
9. The lubricating system as claimed in claim 1, further comprising
at least one sealing mechanism which can be actuated by pressure
applied on a side facing away from the tool clamper.
10. A spindle, in particular a motor spindle, for a lubricating
system, in particular for a single-duct minimum quantity
lubricating system, as claimed in claim 1.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of International
Application No. PCT/EP2016/060826 filed May 13, 2016, which
designated the United States, and claims the benefit under 35 USC
.sctn. 119(a)-(d) of German Application No. 20 2015 102 484.3 filed
May 13, 2015, the entireties of which are incorporated herein by
reference.
FIELD OF THE INVENTION
[0002] The present invention relates to a lubricating system, in
particular, a single-duct minimum quantity lubricating system, with
an aerosol generator and a spindle.
BACKGROUND OF THE INVENTION
[0003] In a variety of technical working procedures when processing
materials, for example, when machining materials, it is
advantageous to provide lubricating and/or cooling at the
processing point to increase process reliability in order, among
other things, to ensure the perfect functioning of a tool and to
increase its service life.
[0004] In order, for example, to keep down the costs for the
respective lubricant and/or coolant and the amount spent on
cleaning the environment and the products produced and, in
addition, to keep down the impact on the environment and on the
health of the operating personnel, attempts have already been made
to manage with small flows of lubricant and/or coolant. This
approach is already known by the term "minimum quantity
lubricating" (MQL), and a corresponding system is usually
designated as a "minimum quantity lubricating system" (MQL system).
Usual lubricant flows and/or coolant flows in such minimum quantity
lubricating systems comprise flow rates of for instance around a
maximum of 50 ml/h and typically approximately between 10 and 50
ml/h, the lubricant or coolant being supplied to the tool/workpiece
in the usual manner as an aerosol.
[0005] An aerosol is to be understood, in general, as a
heterogeneous mixture or a dispersion produced from solid or liquid
airborne particles in a gas. The airborne particles contained in
the aerosol are also called aerosol particles or aerosol
particulates or aerosol droplets. The behavior of an aerosol
depends in the majority of cases on the particles and on the
carrier gas. An aerosol as a whole or unit substantially comprises
a dynamic, flowing, fluid-like behavior or fluid-like
characteristics. In the case of such lubricating systems, for
example, for machine tools or motor spindles or the like, a
lubricant and/or coolant or a so-called "cooling lubricant" is
usually used for the aerosol particles, and additives for corrosion
protection, emulsifying, stabilizing, de-foaming, etc., are
contained, in particular, along with water and oils.
[0006] To date, a distinction is in most cases made between
so-called two-duct minimum quantity lubricating systems (from now
on designated in short as so-called two-duct MQL systems), as are
disclosed, for example, in DE 196 55 334 B4, and so-called
single-duct minimum quantity lubricating systems (from now on
designated in short as so-called single-duct MQL systems).
[0007] In the case of so-called two-duct MQL systems, the aerosol
is not generated until close to the tool holder, frequently by
means of separately supplied lubricant and/or coolant as well as
compressed air, in order to avoid relatively long aerosol transport
paths and to enable as rapid as possible reaction times in the case
of adaptations/changes to the required quantities of lubricant
and/or coolant. Correspondingly, lubricant and/or coolant and air
are guided through the tool spindle in two separate ducts, and the
aerosol is only formed at or in the vicinity of the
rotatable/rotating tool holder.
[0008] In the case of so-called single-duct MQL systems, an aerosol
generator is usually provided in practice which is separate from
the spindle or motor spindle or is arranged externally/outside and
in which the aerosol is generated from lubricant and/or coolant and
compressed air. The aerosol is injected/fed, for example, into an
aerosol line or aerosol transport line and from there is conveyed
to the tool/workpiece via, among other things, the rotary
feedthrough, spindle/motor spindle and tool holder.
[0009] In general, the transport of the aerosol is effected by
means of flowing air or compressed air and is usually controlled,
in this connection, by the pressure of the (compressed) air. In
particular, the direction of transport or the direction of flow is
through the path that the compressed air takes, and the velocity of
flow/speed of flow of the aerosol is also at least determined by
the pressure of the compressed air.
[0010] It has been shown in the meantime in practice that in the
case of so-called single-duct MQL systems, in particular, when used
with machines with spindles, the transport of the aerosol through
the spindle can cause problems which result in the aerosol feed or
the quantities of lubricant and/or coolant flowing to/arriving at
the tool/workpiece being smaller than actually provided/required.
Thus, among other things, losses occur as a result of the aerosol
particles condensing sometimes to a large extent, among other
things, on the transport lines and/or being lost inside the spindle
as a result of leakages, which results in a disadvantageous
increase in the quantities of lubricant and/or coolant to be used
and in unwanted contaminants in the spindle, such that the desired
effects of the minimum quantity lubricating are no longer realized
in a sufficient manner.
SUMMARY OF THE INVENTION
[0011] It is the object of the present invention to propose a
lubricating system, in particular, a single-duct minimum quantity
lubricating system, with an aerosol generator and a spindle or
motor spindle, the lubricating system improving the aerosol
transport, in particular, the transport of lubricant particles
and/or coolant particles above all inside the spindle or motor
spindle.
[0012] Accordingly, a lubricating system according to the present
invention is characterized in that a spindle tube is arranged in
the duct and is non-rotatably mounted on a non-rotating portion of
the rotary feedthrough and extends at least through a portion of
the spindle in the direction of the (rotating/rotatable) tool
clamper, and in that the aerosol generator (non-rotating/static or
arranged externally/outside in relation to the stator of the
spindle) is connected to the (non-rotating/static) spindle tube,
such that aerosol is guided through the (non-rotating/static)
spindle tube in the direction of the (rotating/rotatable) tool
clamper and/or a (rotating/rotatable) tool clamped by the tool
clamper. This means that the spindle tube according to the present
invention is situated/arranged inside the duct or inside a
central/centric hollow space/passage of the spindle or motor
spindle, in particular of a rotating/rotatable rotor of the
spindle, and is in addition non-rotating or fixed/static. A
connection/bearing/fixing to or with the rotary feedthrough or a
(non-rotating) stator of the spindle/motor spindle is
advantageously provided in this case.
[0013] The stationary, i.e. non-rotating or non-rotary spindle tube
prevents a centrifugal force/centrifugal action being generated
onto the aerosol or the aerosol particles as a result of the
effects of flow entrainment of the rotating wall or inner wall as
in the case of the prior art with a rotating aerosol tube/aerosol
duct such that they are condensed on the inner wall and are not
transported/guided or are badly transported/guided further to the
tool clamper or the tool.
[0014] The rotary feedthrough or the corresponding component of the
stator/stator housing makes it possible, in this connection, for an
aerosol or aerosol flow to have a (preferably sealed) transition
between a fixed element/stator and a rotating element/rotor of the
spindle or motor spindle. Within the meaning of the present
invention, the spindle tube in this connection is a component part
or a component of the rotary feedthrough since the aerosol reaches
the tool clamper or the rotor, which rotates in operation, by means
of the stationary spindle tube, which is arranged/fixed in the
rotary feedthrough or the end-face inlet/inflow duct of the
spindle/motor spindle or stator/stator housing.
[0015] A separate aerosol generator is preferably provided, i.e.
arranged externally on the stator/stator housing or arranged
outside/at a spacing with reference to the spindle or motor
spindle, in which the aerosol generator generates aerosol from
lubricant and/or coolant and (compressed) air. The aerosol is
injected/fed, for example, into an aerosol line or aerosol
transport line and from there is conveyed/transported into the
spindle/motor spindle or into the rotatable rotor among other
things by means of the rotary feedthrough and the spindle tube
according to the present invention up to the tool holder or the
tool/workpiece.
[0016] The generation and/or the transport of the aerosol is
preferably effected by means of flowing air or compressed air
and/or by means of pressure or high pressure of up to approximately
3000 bar being applied to the lubricant and/or coolant. The flow
speed of the aerosol or the quantity of lubricant and/or coolant
(per unit time) is regulated/controlled, in this connection, in an
advantageous manner by the pressure of the (compressed) air and/or
by the injection pressure and/or by the injection duration or the
injection rhythm/injection pulsing of the lubricant and/or
coolant.
[0017] For example, to generate an aerosol a high-pressure pump
generates an injection pressure of the lubricant and/or coolant of
up to 3000 bar, preferably for instance of between 250 and 2500
bar. An advantageous electronic control unit of the aerosol
generator or of the high-pressure pump and/or of at least one
advantageous controllable injection nozzle, in particular, of a
high-pressure injection nozzle preferably with a nozzle duct or at
least two nozzle ducts for atomizing/spraying intersecting or
colliding liquid jets, can be used, on the one hand, for the
regulation/control of the injection pressure and/or of the
injection duration and/or the injection rhythm/injection pulse
and/or, on the other hand, for the regulation/control of the air
pressure or of the flow speed of the air or of the aerosol flow.
Advantageous aerosol generation or regulation of the smallest or
minimum quantities of lubricant and/or coolant can be achieved
precisely by means of injecting the lubricant and/or coolant in a
(high-pressure) pulsed manner, for example, injection pulses of a
few microseconds/milliseconds which are interrupted by injection
intervals with a length of seconds or fractions of seconds are
provided. In this connection, it is also possible to realize a very
precise/metered or advantageous adaptation to the quantities of
lubricant and/or coolant required at the tool/workpiece by the most
varied of jobs (tool type such as, for example, milling cutters,
drilling tools, honing tools etc., workpiece diameter, feed,
cutting speed, tool/workpiece material or the like).
[0018] The lubricating system according to the present invention,
in particular, a single-duct minimum quantity lubricating system,
comprises at least one aerosol generator, a spindle, a tool clamper
arranged on the spindle, and a rotary feedthrough arranged on the
side of the spindle lying opposite the tool clamper, wherein a duct
runs through the tool clamper, the spindle and the rotary
feedthrough. Generally, the spindle, tool clamper and rotary
feedthrough are substantially rotationally symmetrical parts, and
the duct, which can be realized, for example, as a bore, is located
on a common rotational axis of spindle, tool clamper and rotary
feedthrough. In this case, the tool clamper can be both an
automatic clamper and a manual clamper.
[0019] Correspondingly, at least in the region of the spindle or of
the rotor, counter to the usual practice in the case of single-duct
MQL systems, the aerosol is not guided primarily or necessarily
through the duct of the rotor, but through a spindle tube according
to the present invention which is arranged in the duct and which is
advantageously mounted non-rotatably on a non-rotating portion of
the rotary feedthrough and extends at least through a portion of
the spindle in the direction of the tool clamper. Correspondingly,
according to the present invention, the spindle tube guides or
transports the aerosol along an inner wall or in the inner
cylindrical hollow space.
[0020] In this way, the aerosol generator is not directly connected
to the entire duct, but to the spindle tube arranged in/inside the
duct, preferably concentrically to the longitudinal axis of duct
and spindle/rotor, such that aerosol is guided through the spindle
tube in the direction of the tool clamper and/or of a tool that is
clamped by way of the tool clamper. This measure leads to a
noticeable improvement in the forwarding of the aerosol to the tool
clamper. External influencing factors are excluded and the
efficiency of the forwarding is increased, in particular, as a
result.
[0021] Experimental tests show that the problems during aerosol
transport are significantly reduced as a result of the provision,
according to the present invention, of a non-rotatably mounted
spindle tube inside the duct portion which penetrates the spindle
and through which the aerosol is transported in the direction of
the tool clamper.
[0022] It is particularly preferred, in this case, if the spindle
tube extends into the tool clamper.
[0023] It is particularly advantageous if the spindle tube is
mounted not only on the rotary feedthrough, but also on the tool
clamper, as this increases the mechanical stability of the spindle
tube and supports the alignment thereof along the rotational axis.
As the tool clamper rotates with the spindle, this bearing
arrangement has to be realized so as to be rotatable.
[0024] A preferred variant, in which such a rotatable bearing of
the spindle tube on the tool clamper can be realized, is
specifically one in which a counter screw with a bearing arranged
thereon, which can be realized, for example, as an air bearing,
sliding bearing, magnetic bearing, shaft seal or mechanical seal,
is screwed in in the region of the duct which extends in the tool
clamper, which counter screw is penetrated by an opening, such that
aerosol emerging out of the spindle tube is conveyed into a coolant
transfer tube.
[0025] In a particular further development of the present
invention, the spindle tube is arranged at least partially inside
an aerosol duct for the conveying/guiding of aerosol such that
aerosol is conveyed/guided both on/along an inner wall of the
spindle tube and partially on/along an outer wall of the spindle
tube. Thus, firstly, the aerosol or a large part of the aerosol can
be transported/guided inside the (hollow cylindrical) spindle tube
and, additionally, secondly, the aerosol or a small proportion can
be transported/guided outside the spindle tube, however, ideally
inside the aerosol duct according to the present invention, i.e.
inside the abovementioned coolant transfer tube. For example,
disadvantageous leaks or contamination of the spindle/motor spindle
or of the rotor, in particular, of the electromagnetic drive system
of the motor spindle, can be effectively prevented/reduced in this
way. This means that the advantageous aerosol duct or the coolant
transfer tube is realized as a protective tube or sealed unit.
[0026] The transfer or distribution of the aerosol to both sides of
the spindle tube, i.e. externally and internally, can be effected
by means of accepted leakages or joints between two adjacent
elements.
[0027] Defined or controlled distribution of the aerosol is
preferably provided. Thus, in an advantageous manner, the spindle
tube comprises at least one control opening or spindle tube opening
for aerosol to flow through. A defined distribution/allocation of
the aerosol flow can be realized by means of the spindle tube
opening or control opening. The proportion of the aerosol or
aerosol flow for the outside and/or the inside or the interior of
the spindle tube or for the aerosol duct can also be
adjusted/adapted or amended, among other things, as a result of the
free/open cross-sectional surface of the spindle tube opening
and/or as a result of an advantageous application of pressure on
the aerosol.
[0028] In an advantageous variant of the present invention, the
spindle/motor spindle includes at least one aerosol unit, inside
which the aerosol is guided or flows and is directed. At least one
sealing device of a shell/housing of the aerosol unit is preferably
provided. Disadvantageous loss or leakage of aerosol, in
particular, of lubricant/coolant, can be effectively prevented as a
result.
[0029] The aerosol duct is advantageously realized as a shell
element and/or housing element of an aerosol unit of the
spindle/motor spindle. As a result, it is possible to realize an
advantageous delimitation or a closure of a preset/defined
region/area about the or outside the spindle tube according to the
present invention which includes the aerosol or in which the
aerosol is guided or regulated. Other components of the
spindle/motor spindle can thus be protected or separated
effectively from leakages or inadvertently escaping aerosol, in
particular from aerosol particles, such as, for example, the
electromagnetic drive system and/or electronic components, etc.
[0030] In an advantageous further development of the present
invention, the aerosol duct is realized as a rotatable duct tube.
This is particularly advantageous precisely in combination with the
static or non-rotatable spindle tube. Thus, an advantageous
transition can be implemented between the static/non-rotatable
spindle tube and the rotating/rotary rotor, which is relevant,
above all, in the case of high-speed spindles/motor spindles
running in part at 20,000 rpm. For example, the transition or the
relative movement of the components is effected by means of
advantageous rotary bearings, such as roller bearings and/or
sliding bearings and/or hydrostatic bearings/aerostatic
bearings.
[0031] Thus, the two, preferably concentric hollow cylinders, i.e.
spindle tube and aerosol duct, are substantially spaced apart from
one another such that for the most part a hollow space or
air/aerosol is present between the two components, as a result of
which friction, abrasion or heat generation is effectively
prevented here. The dimensioning of the rotary bearing between the
two components can be matched structurally in an advantageous
manner to the special requirements or, in part, to the very high
speeds, i.e. enormous speed differences, corresponding to
spindles/motor spindles.
[0032] At least one, in particular two rotary bearings are
advantageously arranged between the spindle tube and the rotatable
duct tube. This means that a structurally or constructionally
advantageous bearing arrangement can be realized. A rotary bearing,
in particular, a sliding bearing and/or roller bearing, e.g. a
needle bearing or the like, is preferably provided in the region
and/or by means of the tool clamper between the spindle tube and
the rotatable duct tube. On the oppositely arranged end region of
the duct tube or of the spindle tube, where applicable, in a
particular variant of the present invention, it is possible to
dispense with a (second) rotary bearing between the spindle tube
and the rotatable duct tube, for example, by the rotatable/rotating
duct tube being supported/mounted (radially) toward the outside on
the stator/stator housing or the like and the spindle tube being
fixed/mounted on the rotary feedthrough. In the last-mentioned
case, a rotary bearing arrangement is only realized indirectly
between the spindle tube and the rotatable duct tube, i.e. by means
of the stator of the spindle/motor spindle.
[0033] In a particular further development of the present
invention, the rotatable duct tube is realized as a pull rod for
operating the tool clamper. Spindles/motor spindles of today
generally already comprise a pull rod, by way of which the tools
may be clamped or released, i.e. the tool clamper is operated/run.
A so-called releasing unit thus comprises, among other things, a
spring system or a disk spring set which holds/presses the tool
clamper in a clamping position, i.e. a position which fixes the
tool clamper. A counter force is generated onto the spring system
or the disk spring set by means of the advantageous pull rod, i.e.
the tool clamper is adjusted along the rotational axis, such that
the tool is able to be released or replaced/exchanged. The dual use
or dual function of the pull rod as an aerosol duct according to
the present invention results in a variant of the present invention
which is particularly favorable structurally and economically.
[0034] As already briefly represented above, it is advantageous for
the aerosol unit to be effectively sealed or to comprise at least
one sealing element such that as small an amount as possible of
aerosol and, above all, as small an amount as possible of aerosol
particles are lost or no disadvantageous leakages and contaminants
occur inside the spindle/motor spindle. The most varied elastomer
seals and/or sliding seals can be provided for this purpose.
[0035] In a preferred embodiment of the present invention, at least
one sealing unit which includes a sealing element, i.e. a sealing
mechanism, is provided which is actuated by means of the pressure
of the aerosol applied on the side remote from the tool clamper.
The sealing unit or the sealing mechanism is preferably realized as
a cylinder-piston unit and/or the sealing element is realized as an
adjustable piston, in particular adjustable in the direction of or
along the rotational axis of the spindle or of the rotor. This
means that it is possible to achieve, in an advantageous manner, an
adaptation or sealing of components of the spindle that are
adjustable along the rotational axis, for example, of a releasing
or clamping unit of the tool clamper, in particular of a pull rod
of the releasing or clamping unit.
[0036] The piston is advantageously realized as an elastomer
element which is adjustable in an advantageous manner along the
rotational axis of the spindle/motor spindle and/or can be acted
upon with pressure of the aerosol/air pressure.
[0037] Many rotary feedthroughs which are used in MQL systems, for
example, such as produced by Ott-Jakob, Deublin or other suppliers,
are characterized in that the rotary feedthrough--for example, in
its non-rotating portion, more precisely in the end region thereof
facing the tool spindle--comprises a sealing mechanism which is
actuated by pressure applied on the side remote from the tool
clamper. As a result of providing the spindle tube mounted on the
non-rotating portion of the rotary feedthrough and of feeding the
aerosol into the non-rotating portion, without further measures the
mechanism is non-active, because aerosol pressure no longer acts on
the sealing mechanism. In such cases, in a preferred configuration
of the present invention, provision is made that, in its tube wall,
the spindle tube comprises an abovementioned spindle tube opening
or control opening at least intermittently in the region of the
non-rotating portion. The result of providing the spindle tube
opening or control opening is that the sealing mechanism is acted
upon with pressure in a sufficient manner such that it becomes
operational again. Lubrication of the spindle tube and/or of the
(rotary) bearing arrangement thereof, in particular of the rotary
feedthrough or mechanical seal, which has an advantageous effect
precisely in the case of modern high-speed motor spindles for
example running at up to 20,000 rpm, is brought about in this way
at the same time. A spindle tube opening or control opening that is
only present intermittently can be realized, in particular, by
using an electrically, manually or mechanically actuatable valve,
such that the defined/metered passage of aerosol is only possible
intermittently or is adjustable.
[0038] It is advantageous when the non-rotatable bearing
arrangement of the spindle tube is realized on the non-rotating
portion of the rotary feedthrough in the region of the duct which
extends in the non-rotating portion, as a result of screwing-in an
extension piece, which is penetrated by an opening in which the
spindle tube is mounted and through which the aerosol is able to
enter into the spindle tube. The bearing configured in such a
manner can also be added subsequently to an existing lubricating
system, in particular, to a single-duct minimum quantity
lubricating system, namely in a simple manner as a result of
screwing-in the correspondingly configured extension piece.
[0039] In an advantageous further development, provision is made
that the extension piece comprises a compressed-air rapid release
coupling. This enables particularly simple connection of an aerosol
supply line, which ensures the supply of the aerosol from the
aerosol generator.
[0040] In a particular further development of the present
invention, the spindle tube is mounted in an electrically
insulating manner in the duct and/or on the rotary feedthrough
and/or on the tool clamper and/or the spindle tube is produced from
a material that is not electrically conductive, for example,
plastics material or ceramic, and/or the spindle tube and/or the
duct is/are provided with at least one electrically insulating
layer for coating the spindle tube and/or the duct in an
electrically insulating manner. This shows that the transport of
aerosol to the tool clamper is further improved, since the aerosol
or the aerosol particles is/are substantially electrically charged.
Expensive and numerous tests or investigations were able to
ascertain that the aerosol or the aerosol particles become
electrically charged when generated/atomized or transported through
the aerosol line and, among other things, interact with the spindle
tube or the aerosol duct. On account of this, in the prior art
aerosol particles or lubricant and/or coolant are deposited on the
inner wall of the aerosol line and of the spindle tube, which is
disadvantageous because the lubricant and/or coolant or the aerosol
particles are not available (immediately or promptly) to the tool
clamper and consequently for workpiece processing. Thus, in the
prior art, the deposited or separated lubricant and/or coolant then
has to be compensated for by an additionally generated quantity of
aerosol particles, which increases the consumption of lubricant
and/or coolant and is not wanted.
[0041] Thus, electric insulation or an electrically insulated
bearing arrangement of the aerosol transport or of the aerosol unit
according to the present invention is particularly advantageous in
order to limit the consumption of lubricant and/or coolant to what
is absolutely necessary or to keep it particularly low.
[0042] For example, the electrically insulating layer or covering
of the spindle tube and/or of the duct is realized as an insulating
varnish film, plasma ceramic (in particular, so-called PEO
technology) or the like. Electric insulation of the aerosol
transport or of the aerosol unit can be implemented in this way
with particularly low structural expenditure.
[0043] Particularly preferred is a realization of an electrically
insulating bearing arrangement or shielding according to the
present invention in which the spindle tube is not mounted in a
rotatable manner preferably on the non-rotating portion of the
rotary feedthrough, for example, by means of a plug connection with
a socket or a cone or the like produced from electrically
insulating material which is connected directly or indirectly to
the non-rotating portion of the rotary feedthrough, and/or in which
the spindle tube is mounted on the tool clamper so as to be
rotatable in a bearing which is connected directly or indirectly to
the tool clamper by means of a socket or a cone or the like
produced from electrically insulating material. The bearing can be
realized, for example, as an air bearing, sliding bearing, roller
bearing, magnetic bearing, shaft seal, mechanical seal and/or can
be produced (directly) from electrically insulating material such
as, for example, ceramic roller bearings and/or can include a
ceramic insulation such as a coating, sleeve or a hollow cylinder
element and/or ceramic rolling elements/ceramic balls etc.,
produced from ceramic material.
[0044] It is advantageous in principle to realize the spindle as a
motor spindle with an electromagnetic drive system, in particular,
with electromagnetic coils and permanent magnets.
BRIEF DESCRIPTION OF THE DRAWINGS
[0045] An exemplary embodiment of the present invention is shown in
the drawing and is explained in more detail below by way of
figures, in which:
[0046] FIG. 1 shows a schematic design of a single-duct MQL system
according to the present invention;
[0047] FIG. 2 shows a schematic design of a first motor spindle of
the single-duct MQL system according to FIG. 1;
[0048] FIG. 3 shows a schematic, front detail of the first motor
spindle of the single-duct MQL system according to FIG. 2;
[0049] FIG. 4 shows a schematic, rear detail of the first motor
spindle of the single-duct MQL system according to FIG. 2;
[0050] FIG. 5 shows a schematic design of a second motor spindle of
the single-duct MQL system according to FIG. 1;
[0051] FIG. 6 shows a schematic, front detail of the second motor
spindle of the single-duct MQL system according to FIG. 5; and
[0052] FIG. 7 shows a schematic, rear detail of the second motor
spindle of the single-duct MQL system according to FIG. 5.
DETAILED DESCRIPTION OF THE INVENTION
[0053] FIG. 1 shows a lubricating system 100, in particular, a
so-called single-duct minimum quantity lubricating system 100 with
an aerosol generator 110 for generating aerosol A, a spindle 120
driven by a motor, a tool clamper 130 arranged on the spindle 120,
and a rotary feedthrough 140 arranged on the side of the spindle
120 lying opposite the tool clamper 130 with a non-rotatably
mounted, non-rotating portion 140a and a portion 140b which is
entrained with the spindle 120. A duct 150 runs through the tool
clamper 130, the spindle 120 and the rotary feedthrough 140 and is
connected to the aerosol generator 110 by means of a feed line
115.
[0054] A spindle tube 160, which is shown simply as a line in the
schematic sketch according to FIG. 1, is arranged in the duct 150.
The spindle tube 160 is non-rotatably mounted on the non-rotating
portion 140a of the rotary feedthrough by way of a bearing 141 and
extends through the spindle 120 in the direction of the tool
clamper 130, where it is mounted in a bearing 131 so as to be
rotatable. In the exemplary embodiment shown according to FIG. 1,
the spindle tube 160 leads into the tool clamper 130.
[0055] By virtue of the fact that a bearing 141 seals the cross
section of the duct 150 against the passage of aerosol, the aerosol
generator 110 is connected in such a manner to the spindle tube 160
that aerosol is only guided through the spindle tube 160 to the
tool clamper 130 and/or to a tool (not shown) that is arranged
therein and that can be clamped by the tool clamper 130.
[0056] The spindle 120, tool clamper 130 and rotary feedthrough 140
with the duct 150 running through them, and the spindle tube 160
which is arranged therein, in this case form an assembly which is
designated below as "spindle assembly" 101.
[0057] The duct 150 and the spindle tube 160 preferably have a
circular cross section and are arranged concentrically to one
another on the common rotational axis of spindle 120 with the tool
clamper 130 arranged thereon and the rotary feedthrough 140.
[0058] The spindle 120 comprises a stator 123 and a rotor 124 and
is preferably realized as a motor spindle. In an advantageous
manner, the rotor 124 includes permanent magnets and the stator 123
electromagnetic coils as the drive means. In addition, advantageous
roller bearings are provided for the bearing arrangement of the
rotor 124 in the stator 123.
[0059] Furthermore, the single-duct MQL system 100 shown also
comprises a control and power supply unit 170 which is connected
via a power chain 171 to the aerosol-generating means and to the
spindle drive, which is not shown separately.
[0060] The cross-sectional representation of the spindle assembly
101 of the single-duct MQL system 100 of FIG. 2 reproduces the
fundamental design of the spindle assembly 101 in a rough manner.
In particular, it shows that the spindle 120 is rotatably mounted
in a spindle housing 121 or stator housing. The space 122 available
between spindle 120 and spindle housing 121 is usually used in
order to accommodate the spindle drive (not shown) in the form of a
motor with a rotor 124 that rests on the spindle 120 and with a
stator 123 that surrounds the rotor 124.
[0061] Furthermore, pull rods 151 which are arranged in the duct
150 and serve for operating the tool clamper 130 are shown, among
other things, in FIG. 2 or FIG. 5.
[0062] FIG. 3 shows an enlargement of a detail of the front
portion, marked with a B, of the tool clamper 130 of the spindle
assembly 101 of the single-duct MQL system 100 according to FIG. 2.
A portion 160a of the spindle tube 160, which is rotatably mounted
in a bearing 131 which is realized by way of example as a needle
bearing, opens out in the portion of the duct 150. However, any
other desired bearings can also be used.
[0063] The bearing 131, which is realized as a needle bearing, is
in an advantageous manner electrically insulated radially toward
the outside, i.e. in particular in relation to the surrounding area
or to further components of the rotor 124, the pull rod 151 and the
stator 123, by means of a socket or a hollow cylinder element or
the like produced from electrically insulating material, for
example ceramic, plastics material, etc. The bearing 131 can also
be realized in an electrically insulating manner as a ceramic
roller bearing, for example, with provision of ceramic rolling
bodies/ceramic balls, etc., and/or an inner race and/or an outer
race produced from ceramic material.
[0064] For example, the arrangement/unit is received and fixed in
the end portion of a counter screw, which is screwed in the inner
wall of the portion of the duct 150 and is penetrated by an opening
134 which opens out in a coolant transfer tube 135. A reliable
mechanical bearing arrangement with a degree of rotational freedom
is ensured in this way for the spindle tube 160, the bearing
arrangement nevertheless ensuring the electrical insulation thereof
in relation to the tool clamper 130.
[0065] In an advantageous manner, a second bearing 141, i.e. on the
other/oppositely situated end of the spindle tube 160, is also
advantageously realized in an electrically insulating manner.
Consequently, even an electrically conducting spindle tube 160, for
example, produced from steel or the like, is electrically insulated
by the aforementioned advantageous bearing arrangement 131, 141.
The achievement here is that electrically charged aerosol A is not
condensed on the inner wall of the spindle tube or attracted
electrically by the inner wall and does not flow with the entire
aerosol stream in the direction of the tool clamper 130. Electric
insulation of the spindle tube 160 is advantageous in principle,
i.e. both for a spindle tube 160 which consists of electrically
conducting material or of material that is not electrically
conducting and/or is mounted/arranged non-rotatably or statically
or rotatably/rotationally in the spindle assembly 101.
[0066] FIG. 4 shows an enlargement of a detail of the rear portion,
marked with C, of the rotary feedthrough 140 with the non-rotatably
mounted, non-rotating portion 140a and with the portion 140b of the
spindle assembly 101 of the single-duct MQL system 100 which
entrains the spindle 120. A sealing unit 142 or a sealing mechanism
142 of the rotary feedthrough 140 can be seen, in particular, in
the representation shown in FIG. 4, the sealing unit or sealing
mechanism developing a sealing action on a sealing surface 164 when
pressure is applied from its side 142a remote from the tool clamper
130 or from a cylinder pressure chamber 163.
[0067] In an advantageous variant of the present invention, the
sealing mechanism 142 or the sealing element thereof, which is
adjustable in the direction of the rotational axis, is realized as
a piston of a cylinder-piston unit. This makes it possible to
ensure the tightness of the aerosol duct or of the aerosol line
inside the spindle 120 or the rotor 124 when a length of the pull
rod 151 is adjusted, in particular, for releasing the tool clamper
130 in operation and/or on account of thermal linear deformation of
the participating components. Leaks of lubricant and/or coolant are
effectively prevented in this way.
[0068] In order to permit such an application of pressure despite
the provision of the spindle tube 160, the latter advantageously
comprises a control opening 162 which is realized in this example
as a bore or opening 162, through which the aerosol A or compressed
air with aerosol particles contained therein is able to pass into a
clear or outer, ring-shaped/hollow-cylindrical portion of the duct
150, such that the required pressure is built up. A valve can also
be inserted into the control opening 162, the valve only releasing
the control opening intermittently.
[0069] Thus, a primary flow of the aerosol A is produced inside the
spindle tube 160 and a secondary flow of the aerosol A is produced
concentrically about the spindle tube 160, i.e. externally between
the outer wall of the spindle tube 160 and, among other things, the
inner wall of the pull rod 151, which is also realized, as a
result, as an aerosol duct 151 within the meaning of the present
invention.
[0070] Furthermore, the achievement of the sealing mechanism 142 or
the concentric arrangement of (stationary) spindle tube 160 with an
outer, sealed (rotatable) aerosol duct or pull rod 151 is that
aerosol A flows from the "rear region" of the spindle 120
corresponding to a certain pressure gradient in a "forward"
direction or to the tool clamper 130 and consequently in an
advantageous manner supplies or lubricates the rotary bearing
arrangement 131 or the sliding bearing and/or needle bearing 131
with lubricant/coolant. This is particularly advantageous precisely
in the case of modern high-speed motor spindles running at, in
part, approximately 20,000 rpm. Inside the outer annular duct, i.e.
between spindle tube 160 and pull rod 151, lubricant and/or coolant
can also definitely be condensed on the side walls as liquid film,
without this being disadvantageous. For, in this connection, the
only thing that is of paramount importance is that the lubricant
and/or coolant is/are transported to the bearing 131 by means of
the flow of the aerosol A and the bearing is lubricated in order to
realize a long service life or to prevent increased wear. A
precisely metered or changing quantity of lubrication is of
secondary importance.
[0071] By contrast, it is possible to realize advantageous metering
or as precise as possible an adaptation of the quantity of the
aerosol A or of the lubricant and/or coolant according to the
present invention with reference to the supply of the tool clamper
130 or of the tool/workpiece. Thus, according to the present
invention, advantageous minimum quantity lubrication can be
realized as a result of avoiding disadvantageous or unwanted
condensing of the aerosol particles or of the lubricant and/or
coolant inside the spindle tube 160 and/or inside the spindle 120
or the rotor 124 at unwanted points. Correspondingly, as in the
prior art, compensation of the condensation/deposits/leaks of the
lubricant and/or coolant inside the spindle 120 or spindle assembly
101 according to the present invention is unnecessary such that the
quantity of lubricant/coolant used/consumed is minimized or
optimized.
[0072] Equally easy to see in the representation in FIG. 4 is the
manner in which the bearing arrangement of the spindle tube 160 is
realized with its portion 160b on the non-rotating portion 140b of
the rotary feedthrough 140. In the end region of the portion of the
duct 150 that penetrates the rotary feedthrough, a thread 154, for
example, is cut into its wall surface, in which is screwed, in an
advantageous manner, an extension piece 143, which is realized as a
screw extension and is penetrated in an advantageous manner by a
bore 144, into which is fitted the bearing 141 which is realized as
a socket or cone produced from electrically conducting material.
The portion 160b of the spindle tube 160 is inserted in an
advantageous manner into the bearing 141, more precisely into the
interior of the socket, the relative diameters being chosen such
that the spindle tube 160 is clamped or sealed in the bearing 141.
Access of the aerosol A to the spindle tube 160 is preferably
ensured as a result of a compressed-air rapid release coupling 146
which is connected to the screw extension 143. Correspondingly,
entry of the aerosol into the spindle tube 160 is possible, but
entry into the duct 150 is not.
[0073] A manual tool clamper 130 is realized in the case of the
second embodiment of the spindle assembly 101 or motor spindle
according to FIGS. 5, 6, and 7. The elements/components shown
otherwise correspond substantially to those of the first embodiment
of the spindle assembly 101 or motor spindle according to FIGS. 2,
3 and 4.
[0074] Of advantage is a single-duct minimum quantity lubricating
system 100, with an aerosol generator 110, a spindle 120, a tool
clamper 130 arranged on the spindle 120, and a rotary feedthrough
140 arranged on the side of the spindle 120 lying opposite the tool
clamper 130, wherein a duct 150 runs through the tool clamper 130,
the spindle 120 and the rotary feedthrough 140, wherein in the duct
150 is arranged a spindle tube 160 which is mounted in a
non-rotatable manner on a non-rotating portion 140a of the rotary
feedthrough 140 and extends at least through a portion of the
spindle 120 in the direction toward the tool clamper 130, and the
aerosol generator 110 is connected to the spindle tube 160 such
that aerosol is guided through the spindle tube 160 in the
direction of the tool clamper 130 and/or of a tool clamped by the
tool clamper 130.
[0075] In the case of a single-duct minimum quantity lubricating
system 100, the rotary feedthrough 140 preferably comprises a
sealing mechanism 142 which is actuated by means of pressure
applied on the side 142a remote from the tool clamper 130, and the
spindle tube 160 comprises, at least intermittently, a control
opening 162 in the region of the non-rotating portion 140a of the
rotary feedthrough.
[0076] In the case of a single-duct minimum quantity lubricating
system 100, the spindle tube 160 is preferably mounted rotatably on
the tool clamper 130.
[0077] For example, for the rotatable bearing arrangement of the
spindle tube 160 on the tool clamper 130, a counter screw 133 is
screwed with a bearing 131 in the portion 150a of the duct 150
which extends in the tool clamper 130, the counter screw being
penetrated by an opening 134 such that aerosol emerging out of the
spindle tube 160 is guided into a coolant transfer tube 135.
[0078] Where applicable, for the non-rotatable bearing of the
spindle tube 160 on the non-rotating portion 140a of the rotary
feedthrough 140, an extension piece 143, which is penetrated by an
opening 144 in which the spindle tube 160 is mounted and through
which the aerosol is able to enter into the spindle tube 160, is
screwed in the portion 150b of the duct 150 which extends in the
non-rotating portion 140a of the rotary feedthrough 140.
[0079] It is advantageous when the extension piece 143 comprises a
compressed-air rapid release coupling 146.
[0080] In general, a lubricating system is advantageous in which
the spindle tube 160 is mounted in an electrically insulating
manner on the rotary feedthrough 140 and/or on the tool clamper
130.
[0081] For example, the spindle tube 160 is non-rotatably mounted
on the non-rotating portion 140a of the rotary feedthrough 140 by
means of a plug connection with a socket or a cone produced from
electrically insulating material which is connected directly or
indirectly to the non-rotating portion 140a of the rotary
feedthrough 140, and/or the spindle tube 160 is mounted on the tool
clamper 130 so as to be rotatable in a bearing 131 which is
connected directly or indirectly to the tool clamper 130 by means
of a socket 132 or a cone produced from electrically insulating
material.
[0082] As an alternative to or in combination with the
aforementioned variants, a lubricating system is advantageous in
which the spindle tube 160 is produced from a material that is not
electrically conducting.
LIST OF REFERENCE SIGNS
[0083] 100 single-duct minimum quantity lubricating system [0084]
101 spindle assembly [0085] 110 aerosol generator [0086] 115 feed
line [0087] 120 spindle [0088] 121 spindle housing [0089] 122 space
[0090] 123 stator [0091] 124 rotor [0092] 130 tool clamper [0093]
131 bearing [0094] 134 opening [0095] 135 coolant transfer tube
[0096] 140 rotary feedthrough [0097] 140a non-rotating portion
[0098] 140b co-rotating portion [0099] 141 bearing [0100] 142
sealing mechanism [0101] 142a side of the sealing mechanism [0102]
143 extension piece [0103] 144 bore [0104] 146 compressed air
rapid-release coupling [0105] 150 duct [0106] 151 pull rod [0107]
154 thread [0108] 160 spindle tube [0109] 160a portion of the
spindle tube [0110] 160b portion of the spindle tube [0111] 162
control opening [0112] 163 cylinder pressure chamber [0113] 164
sealing surface [0114] 170 control and power supply means [0115]
171 power chain [0116] A aerosol
* * * * *