U.S. patent application number 12/515330 was filed with the patent office on 2010-03-04 for method for producing a holding frame or a transmission frame for a stacked piezoactuator and electrostrictive drive with a frame of said type.
This patent application is currently assigned to EUROCOPTER DEUTSCHLAND GMBH. Invention is credited to Peter Janker, Alois Wagner.
Application Number | 20100052480 12/515330 |
Document ID | / |
Family ID | 39183052 |
Filed Date | 2010-03-04 |
United States Patent
Application |
20100052480 |
Kind Code |
A1 |
Wagner; Alois ; et
al. |
March 4, 2010 |
METHOD FOR PRODUCING A HOLDING FRAME OR A TRANSMISSION FRAME FOR A
STACKED PIEZOACTUATOR AND ELECTROSTRICTIVE DRIVE WITH A FRAME OF
SAID TYPE
Abstract
The invention relates to a method for producing a holding or
transmission frame (12, 20) for an electrostrictive actuator, in
particular, a stacked piezoactuator (5). Said method consists of
the following steps: a) a winding spindle (52), corresponding to
the shape of the inner periphery of the frame (12, 20), is wound
with several layers of a unidirectional prepreg for forming a
laminate body; b) said laminate body is hardened; c) the hardened
laminate body in the frame is cut by sections parallel to the
direction of winding. An electrostrictive drive (100) comprises an
electrostrictive actuator (5) in which the length varies during
actuation, and a transmission frame (12) that surrounds the
actuator, is connected to said actuator for initiating the
variation in length of the actuator and for amplifying said
actuator, the transmission frame (12) being made of a prepreg that
is wound in the laminate body and hardened.
Inventors: |
Wagner; Alois;
(Dietramszell, DE) ; Janker; Peter; (Riemerling,
DE) |
Correspondence
Address: |
YOUNG & THOMPSON
209 Madison Street, Suite 500
Alexandria
VA
22314
US
|
Assignee: |
EUROCOPTER DEUTSCHLAND GMBH
Donauworth
DE
|
Family ID: |
39183052 |
Appl. No.: |
12/515330 |
Filed: |
November 7, 2007 |
PCT Filed: |
November 7, 2007 |
PCT NO: |
PCT/DE2007/001997 |
371 Date: |
July 20, 2009 |
Current U.S.
Class: |
310/348 ;
156/152 |
Current CPC
Class: |
H02N 2/043 20130101 |
Class at
Publication: |
310/348 ;
156/152 |
International
Class: |
H01L 41/053 20060101
H01L041/053; B32B 37/02 20060101 B32B037/02 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 20, 2006 |
DE |
10 2006 054 869.8 |
Claims
1. Process for producing a holding or traversing frame (12; 20) for
an electrostrictive actuator, especially a stacked piezoactuator
(5), containing the steps: (a) winding a winding mandrel (52) that
corresponds to the shape of the inner periphery of the frame (12;
20) with several layers of a unidirectional prepreg for forming a
laminate body; (b) curing the laminate body; and (c) cutting the
cured laminate body in the frame by cuts parallel to the winding
direction.
2. Process according to claim 1, characterized in that several
individual cut pieces of the prepreg are wound around the winding
mandrel (52), junctions between the cut pieces being offset between
the layers in the peripheral direction.
3. Process according to claim 1, wherein cut pieces of the prepreg
and cut pieces of a separating film are located in the peripheral
direction along the laminate body in alternation in defined layers
of the laminate body so that along the laminate body in the
peripheral direction, zones with separating film (13; 23) and zones
without separating film (14; 24) are formed.
4. Process according to claim 3, wherein the zones with separating
film (13; 23) and the zones without separating film (14; 24) of
various layers of the laminate body lie on top of one another in
the direction of the layer.
5. Process according to claim 3, wherein prepreg and separating
film are placed in alternation in the zones with separating film
(13; 23) in the direction of the layer.
6. Process according to claim 3, wherein the film is a Tedlar
film.
7. Process according to claim 2, wherein the cut pieces of prepreg
and/or film are positioned by means of positioning stops (56) on
the winding mandrel (52) during winding.
8. Process according to claim 1, wherein the prepreg is a CFK
prepreg, especially a prepreg with an M40J carbon fiber.
9. Electrostrictive drive (100) with an electrostrictive actuator
(5) that changes length upon activation, and a traversing frame
(12) that surrounds the actuator, which is connected to it for
applying the change of length of the actuator and that amplifies
the change in length of the actuator, the traversing frame (12)
being formed from a laminate body composed of wound and cured
prepreg.
10. Electrostrictive drive (100) according to claim 9, wherein
surrounding the traversing frame (12) is a holding frame (20).
11. Electrostrictive drive (100) according to claim 10, wherein the
holding frame (20) is formed from a laminate body of wound and
cured prepreg.
12. Electrostrictive drive (100) according to claim 10, wherein the
holding frame (20) is cemented to the traversing frame (12) along
regions (16) of their peripheries.
13. Electrostrictive drive (100) according to claim 9, wherein the
laminate body of the traversing frame (12) and/or of the holding
frame (20) is formed from several individual cut pieces of the
prepreg that are wound around a winding mandrel (52), junctions
between the cut pieces being offset between the layers in the
peripheral direction of the laminate body.
14. Electrostrictive drive (100) according to claim 13, wherein in
the peripheral direction along the traversing frame (12) and/or the
holding frame (20), there are zones with separating film (13; 23)
and zones without separating film (14; 24) that are formed by
alternating arrangement of cut pieces of the prepreg and cut pieces
of a separating film along the peripheral direction of the laminate
body in defined layers.
15. Electrostrictive drive (100) according to claim 14, wherein in
zones with separating film (13; 23), a layer of prepreg and a layer
of separating film are provided in alternation in the direction of
the layer.
16. Electrostrictive drive (100) according to claim 14, wherein the
film is a Tedlar film.
17. Electrostrictive drive (100) according to claim 9, wherein the
traversing frame (12) and/or the holding frame (20) is formed from
a CFK prepreg, especially a prepreg with a carbon fiber M40J.
18. Electrostrictive drive (100) according to claim 9, wherein the
electrostrictive actuator is a stacked piezoactuator (5).
19. Electrostrictive drive (100) according to claim 9, wherein in
the traversing frame (12), metallic force application elements (8)
are attached to which the electrostrictive actuator (5) is
connected and on which it acts.
20. Electrostrictive drive (100) according to claim 19, wherein the
metallic force application elements (8) in positions opposite one
another are cemented into the traversing frame (12), preferably
along the stacking direction on the two end sides of a stacked
piezoactuator (5).
Description
[0001] The invention relates to a process for producing a holding
and/or traversing frame for a stacked piezoactuator that
contributes to increasing the piezopath. Moreover, the invention
relates to an electrostrictive drive with such a holding and/or
traversing frame.
[0002] For activation of flaps in, for example, a helicopter rotor
or other applications in aviation, piezoactuators or
electrostrictive actuators are known to be used. In particular,
stacked piezoactuators that are also called piezostacks are used
that expand when an electrical voltage is applied and thus make
available an adjustment path. Since, however, in, for example, a
stacked piezoactuator with a length of 100 mm the possible
expansion, i.e., the adjustment path, is approximately in the range
of 0.1 mm, it is desirable to enlarge the piezopath by means of a
traversing mechanism, for example, by a factor of 10 or the like.
For this purpose, placing and clamping the electrostrictive
actuator, especially the piezostack, in a traversing frame that
makes available a path of the activated piezoelement that has been
increased by the traversing factor in a direction perpendicular to
the piezopath, i.e., perpendicular to the change in the length of
the piezoelement, are known.
[0003] Such a frame that is shaped essentially octagonally is
known, for example, from DE 197 39 594 A1. The frame consists of
rigid, metal frame parts that are connected to one another via
flexible articulation sites. There are four fixed frame parts. The
articulation sites are each formed from several elastic bending
elements that lie on top of one another with bending joint axes
parallel to one another and on one side are connected to a fixed
frame part that connects all the bending elements of the
articulation site integrally to one another. The other fixed frame
part that is connected to the articulation site is divided into
several separate individual levers that are each connected to a
bending element of the articulation site. The frame parts are made
integrally solid.
[0004] DE 196 25 921 A1 discloses an arrangement in which the
metallic frame parts of the above-described prior art are replaced
essentially by bending-flexible tie rod parts that are, however,
highly stiff in the lengthwise direction. The tie rod parts are
formed from pieces of steel cable or a fiber composite laminate
with a lengthwise fiber structure that is unidirectional in the
lengthwise direction of the rod and are provided as necessary with
reinforcing elements that increase the tensile strength on their
middle regions located between the actuator pieces and output
members.
[0005] Another piezoelectric actuator is known from DE 196 44 161
C2, in which there are at least two disk-shaped bending elements
that are located coaxially on top of one another and that each have
a carrier plate of hard elastic material with a layer of
piezoelectric material applied on one or both sides. Two bending
elements at a time are connected to one another via at least two
bending joints located on the periphery of the carrier plates, such
a bending joint having at least one bending beam and a rigid spacer
piece that is essentially perpendicular to it.
[0006] So that the traversing frame can work reliably, it is
necessary for the four frame legs that form such an essentially
octagonal frame to have tensile stiffness and to be at the same
time very flexurally soft in the joints. Moreover, it is necessary
for them to tolerate continuous loads at high frequencies, for
example on the order of magnitude of 30 Hz, and, moreover, to have,
as much as possible, such slow damage progression in case of damage
that sudden total failure cannot occur. Rather, damage that arises
and leads to failure should be able to be discovered within the
prescribed inspection intervals. This is especially important in
safety-relevant applications, such as, for example, in applications
of such an electrostrictive actuator for flap control of a
helicopter rotor.
[0007] With respect to these considerations, the object of the
invention is to provide a process for producing a traversing frame
for an electrostrictive actuator, especially a stacked
piezoactuator, which enables economical production of traversing
frames that meet these requirements. Moreover, it is the object of
this invention to make available an electrostrictive drive that is
capable of high performance and is durable.
[0008] This object is achieved with a process for producing a
holding or traversing frame for an electrostrictive actuator,
especially a stacked piezoactuator, with the features of claim 1,
and by an electrostrictive drive with the features of claim 9.
Preferred embodiments are each given in the dependent claims.
[0009] The idea of the invention is to make a holding or traversing
frame in one piece from a wound fiber composite material,
especially by winding a prepreg with unidirectional fibers in the
lengthwise direction of a belt, preferably with unidirectional
lengthwise fibers around a winding core and in a plane parallel to
the winding direction by cutting the cured body that has been
formed into individual holding or traversing frames with a
predefined width. The fiber direction corresponds preferably to the
winding direction or peripheral direction of the holding or
traversing frame.
[0010] The use of prepregs, i.e., layers with fibers that are
already impregnated with resin (preimpregnated), makes it possible
to produce frames of high tensile strength, especially when the
prepreg fibers are fibers with a very high modulus of elasticity,
such as, for example, the carbon fibers called M40J. This yields a
modulus of elasticity of the finished laminate, i.e., of the cured
frame, which is comparable to steel and is, for example, in the
range of roughly 210,000 N/mm.sup.2.
[0011] Preferably, a plurality of layers, for example roughly fifty
layers, are wound.
[0012] The use of a winding process for producing the holding or
traversing frame, moreover, allows economical production, since
several holding or traversing frames can be quickly and
economically produced by a simple winding process, curing and
subsequent cutting, while complex mounting steps for assembling the
frame can be eliminated.
[0013] The use of a large number of prepreg layers at the same time
compared to conventional metal frames, especially steel frames,
greatly reduces the tensile stresses in the frame by roughly a
factor of 1/7. At the same time, existing bending stresses are
reduced by a factor of 1/13. Moreover, the material strength
increases overall; this leads to the traversing frame having a very
long service life and, moreover, becoming damage-tolerant. In
particular, this means that as a result of the different prepreg
layers, in the event of a failure of one of the layers, it can be
assumed that the other layers are not adversely affected at the
same time and thus all individual layers would have to break or
tear in order to result in complete failure of the actuator or of
the holding or traversing frame. Thus, the holding or traversing
frame for a stacked piezoactuator produced in a winding process is
also advantageous with respect to safety requirements, for example
in aviation, in which slow damage progression is critical in order
to ensure with certainty--for maintenance intervals that are as
long as possible--that there is a maintenance instant between the
initial damage detection possibility and subsequent failure and
thus the damage can be reliably recognized before final
failure.
[0014] Due to the fact that a traversing frame produced from
composite material is, moreover, very light, especially much
lighter than a steel frame, it is possible to provide, for example,
a larger number of piezoelements at a total weight of the
electrostrictive actuator that has been kept the same; this in turn
leads to an increase in the power of the actuator, i.e., greater
deflection.
[0015] Advantageously, in the winding process, several individual
cut pieces of the prepreg are wound around the winding mandrel, the
respective junctions between the cut pieces being offset between
the individual layers in the peripheral direction. It is preferably
not a continuous belt, but rather individual cut pieces of the belt
whose length corresponds, for example, to the peripheral length of
the holding or traversing frame. The offset of the junctions
contributes to avoiding weak spots in the holding or traversing
frame and rather to the frame being uniformly loadable due to the
distribution of junctions along the periphery of the holding or
traversing frame.
[0016] The winding mandrel has a shape that corresponds to the
desired peripheral outline of the finished frame, for example a
shape similar to an octagon. Here, in the winding process, the
individual layers are oriented preferably using positioning stops
on the winding mandrel. This makes it possible to refer later in
use to individual junctions and to label them. In particular, the
junctions are defined within the finished holding or traversing
frame.
[0017] According to one especially preferred embodiment, on the
holding or traversing frame along the peripheral direction, there
are zones with low bending stiffness and zones with high bending
stiffness. The zones with low bending stiffness are achieved by
individual layers of the prepreg material being replaced by layers
of separating film in winding in these zones. These zones with
separating film, in which, for example, every other layer is a
layer with separating film, have--compared to a compact laminate--a
flexural stiffness that is reduced by a factor of 1/7000. This
applies especially when, for example, a 0.025 mm thick Tedlar film
is used between a thin, unidirectional CFK prepreg with a layer
thickness of, for example, 0.14 mm. In the zones without separating
film along the periphery, prepreg layers that equalize the film
thickness are placed in the layers in which separating film is
placed in the zones with separating film. Thus, it is possible, for
the bending joints of the traversing frame or holding frame, to
provide fewer flexurally stiff arrangements and thus to ensure
extreme flexural softness, combined with very high tensile strength
in a homogeneous body.
[0018] To make the production process more efficient, for example,
a 300 mm long winding laminate body is produced that is cut into 19
mm wide strips.
[0019] When the traversing frame for an electrostrictive drive,
especially in conjunction with an electrostrictive actuator in the
form of a stacked piezoactuator, is used, it is preferred that
surrounding the traversing frame along the periphery there is an
additional holding frame, preferably produced from a winding body
of prepreg layers with unidirectional fibers. With this holding
frame, the traversing frame can be cemented to less deformable
sites that correspond to flexurally stiff zones in which preferably
no film has preferably been placed in the traversing frame, and in
addition, a holding flange can be cemented or placed in the holding
frame on one of the ends in the lengthwise direction of the
traversing frame between the traversing frame and the holding
frame, and the traversing frame is attached, for example, in the
rotor blade with the holding flange. Cementing along regions of the
periphery between the traversing frame and the holding frame
ensures a reliable connection and uniform traversal of the
piezopath or the path of the electrostrictive actuator.
[0020] For connecting the stacked piezoactuator or the
electrostrictive actuator to the traversing frame, preferably on
the lengthwise ends of the traversing frame, force application
elements are placed in the latter and are attached, for example
cemented there. The force application elements are preferably made
of metal and are essentially U-shaped or semicircular so that they
correspond to the inside periphery of the traversing frame on the
lengthwise ends. When such force application elements are cemented
at opposite positions into the traversing frame so that they form
an uppermost and a lowermost terminal element along the stack
direction of the stacked piezoactuator, the change in the length of
the piezoelement can be easily transferred to the traversing
frame.
[0021] The invention is described below using the attached figures,
in which
[0022] FIG. 1 schematically shows a top view of an electrostrictive
actuator without the holding frame;
[0023] FIG. 2 shows a perspective view of an electrostrictive
actuator with a holding frame;
[0024] FIG. 3 schematically shows the traversing frame;
[0025] FIG. 4 schematically shows a holding frame;
[0026] FIG. 5 shows a perspective view of the electrostrictive
drive for attachment in, for example, a rotor blade of a
helicopter;
[0027] FIG. 6 shows a winding mandrel for producing the holding
and/or traversing frame.
[0028] FIGS. 1 to 5 show one embodiment of an electrostrictive
drive 100 (FIG. 5) with a frame arrangement 10 that contains a
traversing frame 12 and a holding frame 20 according to the
invention.
[0029] FIG. 1 schematically shows the manner of operation of an
electrostrictive drive with a traversing frame 12. In particular,
there is an electrostrictive actuator that is formed as a stacked
piezoactuator 5. When a voltage is applied from a voltage source
that is not shown, the stacked piezoactuator 5 produces a change in
length in itself that is shown in FIG. 1 as the piezopath P. The
stacked piezoactuator 5 in its stack direction on its two stack
ends is connected by way of suitable connecting means, for example
cement layers 6, to force application elements 8 that for their
part are in turn connected to the traversing frame 12. The force
application elements 8 are cemented into the traversing frame 12,
for example, and are made of metal in order to provide stable
application of force and to hold the stacked piezoactuator 5.
[0030] The force application elements 8 are provided on both sides
as the termination of the stacked piezoactuator 5 in its stacking
direction that corresponds to the direction of the change in length
of the stacked piezoactuator 5, and are essentially U-shaped in the
top view shown in FIG. 1 with a closed inner surface. Their outer
peripheral shape on the surface that is in contact with the
traversing frame 12 corresponds essentially to the inner peripheral
shape of the traversing frame 12, especially on its lengthwise
ends.
[0031] In this case, the lengthwise direction is the direction in
which the piezopath arises, i.e., the stack direction of the
stacked piezoactuator 5 or the direction of change in length of a
generally electrostrictive actuator. The traversing frame 12 is
essentially octagonal in the top view shown in FIG. 1 or rhombic
with flattened corners. The stack direction of the piezoactuator
corresponds to the longer of the two diagonals of the rhombus and
is the lengthwise direction L.
[0032] The arrangement consisting of the stacked piezoactuator 5,
the force application elements 8 and the traversing frame 12 that
is shown in FIG. 1 is symmetrical both with respect to the
lengthwise axis L and also with respect to an axis that runs
perpendicular to it in the plane of the drawings. The traversing
frame 12 can be flexibly deformed.
[0033] The octagonal configuration of the traversing frame 12 on
the ends in the lengthwise direction L and the middle sections
between the lengthwise ends (corresponding to the corners of the
rhombus) has comparatively rigid coupling regions 11 and 12 in each
case, while the zones 13 of the traversing frame 12 that lie in
between are made as comparatively flexurally soft zones.
[0034] When the length of the stacked piezoactuator 5 changes along
the piezopath P, for example in expansion under an electrical
voltage, the traversing frame 12 follows the deformation
accordingly, by its fixed connection on the force application
elements 8 to the stacked piezoactuator 5 and by flexural softness
by means of the zones 13, and its geometrical shape, traversal,
especially an enlargement, of the piezopath P, arises, for example
by a factor of 10. Accordingly, the piezopath P that has been
enlarged by a factor of 10 can be tapped along the deflection T.
For example, for a stacked piezoactuator with a length of roughly
100 mm that has a typical expansion of 0.1 mm when an electrical
voltage is applied, a path of 1 mm for a transfer ratio of 1:10
along the enlarged path T of the traversing frame can be
tapped.
[0035] In addition to flexural softness through zones 13, it is
important for the traversing frame 12 that it has legs with tensile
stiffness that correspond to zones 13.
[0036] FIG. 3 shows the traversing frame 12 in more detail. The
traversing frame 12 is formed altogether from a fiber composite in
a winding process. For this purpose, several layers of a prepreg
along the winding direction W that is shown in FIG. 12 and that
corresponds essentially to the peripheral direction of the
traversing frame 12 are laminated. The traversing frame 12 that is
shown in FIG. 3 is preferably formed from several individual cut
pieces of the prepreg that are placed on top of one another and
have interfaces offset between two layers along the peripheral
direction or winding direction W.
[0037] As is schematically indicated in FIG. 3, along the
peripheral direction, the traversing frame 12 contains zones 13
with elevated flexural softness and zones 14 that are comparatively
rigid. These zones 14 correspond to the coupling sites 11 in their
position.
[0038] The flexurally soft zones 13 acquire their higher flexural
softness compared to zones 14 by a separating film being placed
between individual layers of the fiber composite prepreg when the
frame 12 is being wound. The separating film is, for example, a
0.025 mm thick Tedlar film. The film contributes to the individual
layers of the prepreg being connected less tightly to one another
and being able to move more easily against one another, which
contributes to the deformation capacity in the zone 13. For
example, one separating film layer at a time can be placed between
two layers of prepreg in zone 13, i.e., separating film layers and
prepreg layers alternate along the lamination direction of the
winding body that shapes the traversing frame 12.
[0039] In zones 14, conversely, there is no separating film. In
other words, in zones 14 without separating film, there is a pure
body laminated from prepreg in which the layer thickness that
arises by insertion of separating films between the prepreg layers
in zones 13 can be equalized by additional prepreg layers, so that
the traversing frame 12 has an essentially constant thickness or
one that passes uniformly into one another. As is shown in FIG. 3,
the zones 14 of compact laminate are located both on the two ends
in the lengthwise direction of the traversing frame 12 and also at
the coupling sites of the legs between the two end zones 14 of pure
laminate, and four zones 13 are provided with separating film in
alternation therewith around the periphery of the traversing frame
12. Preferably, the transitions between the separating film and the
laminate, i.e., between zones 13 and 14, are made such that they
are likewise offset with respect to the individual layers to one
another somewhat in the peripheral direction so that a theoretical
failure site cannot arise due to repeated transitions at a certain
site along the peripheral direction of the traversing body 12.
[0040] When a preimpregnated layer with high modulus carbon fibers
M40J is selected as a prepreg, and, for example, 52 layers are
wound to form a traversing frame 12, and between two layers of
prepreg at a time in zones 13 a layer of separating film is placed,
the film in sum has a total thickness of roughly 1.2-1.3 mm, which
can be equalized by several layers of the prepreg, of which one
layer is, for example, 0.14 mm thick. The zones 14 without the
separating film compared to zones 13 with the separating film have
increased flexural stiffness that is increased by a factor of 7000
for the aforementioned parameters.
[0041] The selected prepreg is preferably a unidirectional CFK
prepreg, in which preferably the aforementioned high modulus carbon
fibers are used, and in each case, the fibers should be oriented
along the winding direction W to ensure optimum tensile
stiffness.
[0042] To attach the traversing frame with the force application
elements 8 that are mounted in it and that are shown in FIG. 1, and
the electrostrictive actuator in the form of a stacked
piezoactuator 5, for example to a helicopter rotor blade, it is
necessary for the attachment to be dimensioned such that, on the
one hand, it allows high-frequency deformations of the traversing
frame and, on the other hand, absorbs or tolerates the forces that
arise in the rotor blade, i.e., for example a centrifugal
acceleration of 800 g that acts on the actuator (corresponding to a
centrifugal force of 4700 N).
[0043] For this purpose, as shown in FIG. 2, the traversing frame
12 is placed in a holding frame 20 that is provided with a holding
flange 26.
[0044] The holding frame 20, as is shown in FIG. 4, is likewise
produced preferably from a winding body of a fiber composite
material, however differently from the traversing frame 12 its
being only symmetrical to the lengthwise axis L, but as a result of
providing the holding flange 26 (FIG. 2) that is placed between one
lengthwise end of the traversing frame 12 and the holding frame 20
its not having axial symmetry with respect to one axis
perpendicular to the lengthwise axis of the holding frame. The
holding frame 20 is also formed in the same manner as the
traversing frame 12 with zones with separating film 23 and zones
without separating film 24 that alternate in the peripheral
direction that corresponds to the winding direction W of the
holding frame 20. To attach the traversing frame 12 to the holding
frame 20, the latter are cemented against one another by cement
sites 16 (see FIG. 2) that are provided essentially along the
respective zones 14, 24 without separating film, with the exception
that in one of the lengthwise-side ends of the holding frame 20,
i.e., in one of the two end-side zones 24 without a separating
film, instead of a connection to the traversing frame 12, the
holding flange 26 is cemented in or attached there. Between the
cement sites 16 along the zones 13 and 23 with separating
film--along the regions 17--the holding frame 20 and traversing
frame 12 are not connected to one another.
[0045] The arrangement 10 that is shown in FIG. 2 and that
corresponds essentially to the electrostrictive drive 100, the
stacked piezoactuator 5, however, not being shown in FIG. 2, is
finally provided with holes on one housing side and the drive side
for attachment (see FIG. 5). For this reason, in the coupling zones
11 along the long sides of the traversing frame 12 or holding frame
20 in the regions 14 without separating film, there are through
holes that in addition to preventing cracks or breaks in the zone
of the holes are reinforced by additional fabric reinforcing layers
30 being cemented on the outside to the holding frame and on the
inside in the traversing frame. These layers additionally prevent
damage of the electrostrictive drive 100 in the region of the holes
under operating loads. A dowel screw 40 is placed in the intended
hole for housing-side attachment. For attachment of the measurement
frame 42 on the drive side, a sleeve 41 is routed into the hole
through the traversing frame 12 and the holding frame 20.
[0046] FIG. 6 finally shows a winding mandrel 50 that can be used
to produce the traversing frame 12. The winding mandrel for the
holding frame is not shown and is made similarly, but as a result
of the aforementioned asymmetry of the holding frame 20, it is
likewise made asymmetrical. The winding mandrel 50 contains a
mounting shaft 51 with which it can be clamped, for example, in a
turning device. The direction of rotation of the mounting shaft 51
in the turning device is shown schematically by the arrow D. The
winding mandrel 50 has a width B between the end plates 54 into
which the prepreg can be wound, which is, for example, 300 mm,
i.e., a multiple of the end width of the holding frame 20 or
traversing frame 12. Thus, by a single winding process, several
holding and traversing frames 20 and 12 can be produced that--after
the laminate is cured--are cut into pieces of the corresponding
width, for example 19 mm.
[0047] The end plates 54 of the winding mandrel 50 are additionally
provided with positioning stops 56 for strips of film. Thus, for
example, the strips of film can be placed over a greater width
(including the width of the end plates), while the prepreg layers
lie only within the zone between the two end plates 54.
[0048] Thus, reliable positioning of the film layers can be
ensured. When the positioning stops 56 have, for example, beveled
side surfaces 57, film layers lying on top of one another are
slightly offset to one another along the winding direction so that
there is no abrupt transition between the zones 13 with separating
film and zones 14 without separating film in, for example, the
traversing frame.
REFERENCE NUMBER LIST
[0049] 5 piezoactuator [0050] 6 cement layer [0051] 8 force
application element [0052] 10 frame arrangement [0053] 11 coupling
region [0054] 12 traversing frame [0055] 13 zone [0056] 14 zone
[0057] 16 cementing site [0058] 17 region [0059] 20 holding frame
[0060] 23 separating film [0061] 24 separating film [0062] 26
holding flange [0063] 30 fabric reinforcing layer [0064] 40 dowel
screw [0065] 41 sleeve [0066] 42 measurement frame [0067] 50
winding mandrel [0068] 51 mounting shaft [0069] 52 winding mandrel
[0070] 54 end plate [0071] 56 positioning stop [0072] 57 side
surface [0073] 100 electrostrictive drive [0074] B width [0075] D
direction of rotation [0076] L lengthwise axis [0077] P piezopath
[0078] W angle direction
* * * * *