Source: https://patents.google.com/patent/WO2008141886A1/en
Timestamp: 2018-09-19 19:55:45
Document Index: 70328958

Matched Legal Cases: ['art 8', 'art 8', 'art 8', 'art 8', 'art 8', 'art 8', 'art 8', 'art 8']

WO2008141886A1 - Electromechanical motor, especially piezoelectric microstepper drive - Google Patents
Electromechanical motor, especially piezoelectric microstepper drive Download PDF
WO2008141886A1
WO2008141886A1 PCT/EP2008/054909 EP2008054909W WO2008141886A1 WO 2008141886 A1 WO2008141886 A1 WO 2008141886A1 EP 2008054909 W EP2008054909 W EP 2008054909W WO 2008141886 A1 WO2008141886 A1 WO 2008141886A1
PCT/EP2008/054909
Robert Wolfgang Kissel
Karl-Heinz Mittenbühler
The invention relates to a motor which comprises two drive elements (19a, 19b), especially piezoelectric bending actuators, having effective directions that are perpendicular to each other. These actuators (19a, 19b) act upon a drive ring (1) to thereby rotate a shaft (39). Two tension-compression bars (3a, 3b), which are parallel to an effective direction, are connected to the drive ring (1), have respective joints (5) at their ends and are connected to the ends of a diagonal bar (4), relative to which the ring (1) can be displaced in the other effective direction. The diagonal bar (4) itself can be displaced relative to fixing elements (12) to an effective direction via a diagonal suspension. The drive according to the invention is compact, having actuators that are non-radially hinged to the ring (1).
Electromechanical motor, especially a piezoelectric micro-step drive
The present invention relates to an electromechanical motor, especially a piezoelectric actuator.
The cockpit of a motor vehicle tried to realize an optimal interplay of design and technology. In view ¬ field of the driver while there are various pointer instruments. This pointer instruments must conform at different tech ¬ African requirements and zen a konkurrenzfähi ¬ gen price for the mass production of motor vehicles besit-. An example of such a pointer instrument is the "measuring unit 2000" by Siemens VDO.
The "measuring unit 2000 'is based on a squat with a single-stage worm gear stepper motor drive. The four-pole stepping motor is formed by two 90 ° phase-shifted to each other Phasenwin ¬ kel sinusoidal Spulenstromver- run controlled as a function of time. The sign of the phase shift determines the rotational direction and the frequency of the rotational speed of the motor shaft. As part of a vol- len period of 360 ° of the sinusoidal current course of up to 128 intermediates can be reproducibly. The use of these intermediates is as microstep drive called.
A complete actuator "measuring unit 2000" which includes the above-characterized stepper motor consists of twelve items. The stepping motor itself is composed of two coils with a common stator core and a permanent magnet rotor ¬ together. In terms of component costs, the coil and the permanent magnet beat most impact. Decisive for the price, the cost of which close approximately propor ¬ tional increase the number of components of the actuator in addition to the material costs as well. From EP 1098429 Bl is known for a new Motorprin ¬ zip, that is, without rotating coils, working of electromechanical motor, moved at the during operation by a time-offset actuation of at least two elec- romechanischen drive elements, a drive ring circumferentially is such that by an immediate Kraftuber- supporting the drive ring on the - in particular located within the drive ring - this shaft is rotated. The breadth of current displacement movements of the drive ring can be accessed by z. B. piezoelectric, magnetostrictive, electrostrictive or electrodynamically driven actuator caused ¬ the, so that a better result lantrieb suitable for mass production STEL terms of material costs and herstel ¬ development costs. The piezo actuators are mounted on the drive ¬ ring that their respective stroke acts radially on the on ¬ operating ring, which may contain further measures are taken in order to achieve a symmetrical possible introduction of forces ¬ processing to the drive ring.
Among the last-mentioned technical circumstances to (constancy of Drehgeschwindig ¬ accuracy that is independent of the instantaneous position of the shaft) results in a true with regard to the optimized drive function with the best synchronization characteristics without torque fluctuations. but in particular the longitudinal extension and the radial arrangement of the bending actuators puts it at that with that the flat drive variants require a considerable amount of space in the plane and mostly appear less compact. Compact flat drives but are urgently needed because of the predefined in the cockpit instruments very cramped Bauraumverhaltnisse.
The object of the present invention is optimized with respect to number of parts, manufacturing cost, space requirement and functionality step drive, in particular a small actuator for measuring elements of the cockpit instruments, be ¬ riding observed. This object is achieved by an electromechanical motor, especially a piezoelectric micro-stepping motor according to claim. 1 Advantageous embodiments and further developments of the present invention will become apparent from the following description, the drawings and the dependent claims.
The inventive electromechanical stepper drive has the following features:
Two electromechanical, preferably piezoelectric, An ¬ drive elements (actuators) having approximately perpendicularly aligned directions of action, and so rotatably mounted in an on ¬ drive ring shaft so that the drive ring by a displacement of the piezoelectric Antriebsele ¬ elements into the respective effective direction can be excited to an immediately transmitted to the shaft sliding motion so that the shaft rolls in the drive ring and rotates thereby. Further, the driving ring by means of two to one another and parallel to one of the two effective directions train-pressure point, which each have at their both ends in each case a hinge on ¬, is connected to the ends of a diagonal bar, so that the drive ring relative to the diagonal bar in the form of a shear vertical to the other, so for both train-pressure Stava, effective direction is displaceable. In addition, the diametrically opposite ends of the at least from ¬ cut as obliquely to the two effective directions extend ¬ the diagonal bar respectively by means of a plane parallel to the other active ¬ direction train-push rod, the back having at its two ends a hinge, in each case a fixing ¬ element connected, wherein the fixing element of the one rod and the connection point of the other rod to the diagonal ¬ rod - and vice versa - to one another in each case approximately along a parallel to the opposite to a direction of action, so that the brace member relative to the fixing elements in the an effective direction is displaceable.
The inventive Ringaufhangung combines (the drive-ring partially framing) Parallelaufhangung for one of the two directions of action with a Diagonalaufhangung for the other, vertical, effective direction to the first and he ¬ enables relatively due to the specific, the articulated connection IH rer elements or parts each other the desired Ki ¬ kinematics. As a consequence of the structure of the connection of the drive ring to the diagonal bar in combination with the structure of the connection of the diagonal bar to a housing or connected mechanically rigidly connected parts of the drive ring is relatively almost kraftefrei displaceable relative to the housing in the xy-plane in each ¬ de direction, but torsionally stored. The overall structure is referred to herein as Tangentialkinematik. A particularly noteworthy is the stringent planar structure of the inventive Ringaufhangung or xy kinematics is considered, which can dispense At ¬ drive ring to be arranged elements, such as spacers parallel to the plane of.
Each acting on the drive ring through the torque is transmitted to the housing Tangentialkinematik without since ¬ is rotated significantly in the ring. Therefore, first, in contrast to the prior art, no longer in the radial force introduction of the forces provided by the bending actuators in the drive ring taken posted for the center of the ring bore, as the caused by the non-radial, eccentric force application torque to the drive ring through the Tangentialkinematik and the Gehäu ¬ se is essentially taken torsion. This eröff ¬ net the possibility of a space-saving arrangement of drive-elements, in particular along the sides or halves of the drive ring, thus for example to two parallel arranged diagonally sides of a right (outward) operating at ¬ ring. Ensures a highly compact, space-saving ¬ the construction of the stepper drive can be realized. The inventiveness proper step drive is also characterized by a very small number of simple components, so that is particularly suitable for mass production. Further, occurring due to different thermal expansion of plastic and actuator thermal detuning of the actuator is constructively reliably absorbed. By positive engagement, eg. Example by means of a trained between drive ring and shaft gear tooth ¬ voltage, a very high positioning accuracy of the drive erfindungsge- extent is achieved in the pure controlled operation to have to take without sensors and a control circuit.
According to the invention is - in favor of optimizing the compact ¬ ness - not necessarily perfect symmetrical force trans- mission to the drive ring sought. The consequences in terms of function propose any consequent such. As light synchronized and torque fluctuations can be reduced so far by other measures that customer specifications are still met. In particular, small speed variations can (deviations from
Soll) are compensated for by modulating the pure sine wave Ansteu ¬ augmentation of the drive elements.
In a particularly advantageous embodiment of the inventions fertil the joints of the train-pressure point of the Ringaufhangung are each formed as a flexure bearing. The solid-state joints may be formed in a short section in each case by a tapering of the Querschnit ¬ tes the train-pressure point, which is particularly advantageous in terms of production.
Looking at the geometrical implementation of the Tangenti- alkinematik it is favorable to arrange the to the one active ¬ direction arranged parallel train printing character along opposite ¬ of the sides or halves of the drive ring and in each case to a gain of the drive ring to link disposed at a side facing away from the diagonal bar or half of the drive ring is arranged. It is further guns ¬ tig to choose the length of the between the drive ring and diagonal bar in ¬ ordered, parallel to the other effective direction train-pressure rod is smaller than the distance between the two to the one effective direction are arranged parallel train-pressure Stava. A favorable geometric arrangement with respect to the Diago ¬ nalstabs let be achieved in that the diagonal bar consists of an approximately parallel with the other effective direction in ¬ parent agent stucco and from end portions which are angled towards the central piece, the end sections are angled with the same sense of rotation, so that the ends of the diagonal bar opposite to each other diametrically approximately.
Geometrically advantageous, that is, substantially in production-technical point of view, it is furthermore, the Fixierele ¬ ment that the parallel with the other effective direction is arrange ¬ th, binds along the side facing away from the actuator ring side of the slide ¬ gonalstabes extending train print bar, at befes- term to a rectangular to ¬ approaching mechanically rigid frame part. In one development of this embodiment, the frame part is designed as a housing part of the stepper drive is ausgebil ¬ det. With respect to the other fixing element, which the arranged parallel to the other effective direction, tailing along the side facing the drive ring side of the diagonal bar which run train print bar, an integration in egg ¬ nem floor element and / or lid of a housing of the step ¬ drive is advantageous wherein said provided for connection to the fixing element ¬ end of the train-push rod is provided with a connected on Fi ¬ xierelement Endstuck. The Endstuck accordingly provides in a simple way a punctual that we ¬ sentlich planar structure of the Ringaufhangung not durchbre ¬ sponding, connection between the plane of the drive ring and the cover or bottom member of a housing forth.
The two electromechanical drive elements can be particular ¬ It benefits in, designed as bending transducers, preferably piezoelectric bending transducer ¬ cal.
Such solid-state bending actuators based on piezoelectric ceramics are used in a variety of designs for many years versatile in the industry. They are characterized by small size, low power consumption and high reliability. For example, a piezoelectric bending actuator is a life ¬ period of at least 10 9 cycles in industrial environments. The next in a small actuator for example Zeigerinstru ¬ elements for use bending transducers are typischerwei- se so dimensioned that it has a free deflection in the range of about 0.2 mm to 2 mm aufwei ¬ sen at its moving end. In addition, a locking force in the Be is ¬ ranging from 0.5 N to 2 N reached in the case of Auslenkungsblockierung the freely movable end of the bending transducer. The near approximately geradli- nige deflection of the bending transducer is in each case transversely in relation to its largest longitudinal extension. The direction of the deflection corresponding to the direction of action of the bending transducer is thus approximately orthogonal to the longitudinal axis of the bending transducer.
A particularly compact variant of the inventive step drive is obtained by an arrangement in which a respective arranged parallel to the one or other direction of action of the reinforcements on the drive ring, long corresponds one side or half of the drive ring extending train print bar is attached, which at its both ends each having towards a flexure bearing, and on the averted from the reinforcement end in each case the moving end of which is arranged a perpendicular to the respective train print bar, along one side, or - in a non-rectangular shaped drive ring - along one half of the drive ring ver ¬ current bending transducer is coupled. By this shear ¬ flexible articulation of the two electro-mechanical, preferably ¬ as piezoelectric drive elements to the drive ring there is the advantage that their directions of movement coupled ent ¬ from each other, so that the drive elements do not or negligibly low behin ¬ countries in their movement. In the application of force is no Verlustener ¬ gies occur. In addition, the arrangement or Anlen- is effect of the bending transducer according to this embodiment saves space. According to a further development of the embodiments with bending transducers, it is advantageous housing parts form trainees the drive ring, the train-pressure point and the diagonal bar as a einstuckig manufactured in plastic injection molding technique drive module, the bending transducer is a ¬ are sprayed with in the drive module. The realization of the drive module in ¬ art injection molding technique is simple and inexpensive manner, and by the inclusion of bending actuators in the injection Ar ¬ beitsgang the number of manufacturing steps is further sheet reduced.
For rigid mounting of the drive module and for rotatably supporting the associated shaft, it is advantageous to provide a Annae ¬ hernd cuboidal housing with a floor element and a lid, wherein the bottom member, a central bearing ¬ block with a bearing surface and having a first Lagerboh ¬ tion and a second bearing bore is provided for the shaft in the lid, and wherein the fixing elements arranged in the Gehäu ¬ se and fixed to or integrated, that can roll off at least one cylindrical Abrollflache the shaft in an associated Abrollflache an annular bore of the drive ring.
The preferred embodiments of the present invention will be explained in more detail with reference to the accompanying drawings. Show it:
FIG. IA and IB an embodiment of a fixed in a housing frame ¬ drive module for the inventive step drive respectively in plan view and in a perspective view;
Fig. 2A and 2B, respectively, in the same view as FIG. 1, the local drive module, but with inserted bending actuators
Fig. 3A is a plan view of a drive module with a in the x direction and, Fig. 3B, a deflected in the y-direction An ¬ drive ring, Fig. 4A and 4B, each in the same view as Fig. 1, a housing floor element for mounting the shaft and the drive ¬ module,
Fig. 5A and 5B, respectively in the same view as FIG. 1, a fitting to the housing according to Figure 1 or 4 Lid
FIGS. 6A and 6B, respectively in the same view as FIG. 1, a view of a Bugelfeder,
FIGS. 7A and 7B, respectively in the same view as FIG. 1, a shaft for the inventive step drive,
Fig. 8 is an axial cross section along the z-axis through the gehausten drive in the assembled state.
According to the invention, a piezoelectric stepping motor is brought to ¬, which makes it possible to produce by a superposition of suitable periodic linear movement of the bending transducer a continu ous ¬ and uniform rotation. To this end, the bending transducers 19a, 19b, cf. be. Such coupled Figure 2, by means of a displacement in the xy plane aware paid Ringaufhangung in which the inventive Tangentialkinema- policy is implemented on a flat drive ring 1 that this along the mutually perpendicular active directions x and y of the bending transducers 19a, 19b (cf. FIG. 2) is translatable. The substantially (can be integrated in the frame member 8) of the fixing member 12 together with the drive ring 1, the diagonal bar 4, the train-pressure Stava 3a, 3b, 6a, 6b, IIa, IIb and, where appropriate, the inte ¬ th bending transducers 19a, 19b , unit formed is to be referred to as consequences ¬ 'drive module'. The drive module can be produced using an injection molding technique from polyethylene, injection-molded plastic, POM or from other suitable materials.
Figure 1 shows the substantially planar, and therefore easy to produce structure of the drive module in top view and in perspective. It consists initially of a drive ring 1, which contains a cylindrical annulus bore 2 whose axis z. For example, with the z-axis of a Cartesian coordinate natensystems coincides, the xy plane extending parallel to the sheet plane. The drive ring 1 is formed perpendicular example ¬ half and with its edge (outer) and sides 14 parallel to the two mutually perpendicular directions of action of the drive elements 19a, 19b exclusively directed. The drive ring 1 is by means of two to ¬ approximately parallel to each other and extending in its longitudinal extension in aligned approximately parallel to the x-direction train-pressure point 3a, 3b is connected with a mechanically sufficiently rigid brace member. 4 The connection of the train-pressure point 3a, 3b to the drive ring 1 and the diagonal bar 4 takes place allow 5. Festkorpergelenke using so-called Festkorpergelenke as ordinary joints (but only within a BE ¬ delimited angular range, this but without play) a nearly unobstructed rotation of the connected elements relative to each other. Their function is based on the bending principle. It is sufficient ¬ the local bending by a targeted reduced copy ¬ tion of the rod cross-section in a short section. The re ¬ duced rod cross-section leads to a greatly reduced bending stiffness. Since the Querschnittsverjungung is very localized Siert, the axial spring rate (stiffness) of the rod will hardly reduced. The Querschnittsverjungung can be carried out perpendicular to the plane in the (leaf) level and / or as a sidecut. The geometrical configuration of the hard ¬ korpergelenke regards the axial rigidity and stiffness torsionally, and the degree of localization and their influence on the function and manufacture of the actuator can, for example, with the help of finite element models to be optimized in terms of the particular application.
The paired parallel to each other in about and extending parallel to the x-axis arrangement of the rod members 3a, 3b has in Kom ¬ bination with its connection to the mechanically sufficiently rigid drive ring 1 and the mechanically sufficiently rigid brace member 4 by Festkorpergelenke 5 for Fol ¬ ge, that the drive ring 1 relatively easily (ie almost kraftefrei) can be displaced relative to the diagonal bar 4 in the form of a shear in the y direction. A torsion of the drive-ring 1 and a displacement of the ring in the x-direction-relative to the diagonal bar 4 converts this structure against very ho ¬ hen resistance.
The two diametrically opposite ends of the diagonal bar 4 are connected by means of two approximately parallel to each other ver ¬ current and in its longitudinal extension in aligned approximately parallel to the y-direction train print character 6a, 6b with the Ge ¬ housing of the stepper drive. In the case of the rod 6a the Gehauseanbindung for example, via a partially vertically extending to the rod 6a Endstuck 7 of the rod 6, the force-stiff with a not shown Bo ¬ nevertheless, and / or cover member of a housing mechanically towards ¬ sufficiently stiff or formschlussig is connected, z. For example, by pressing, pinning, welding, gluing, etc. The rod 6b is connected at its connection to the diagonal of the rod 4 from ¬ facing end with a frame member. 8 The frame part 8 can ¬ integral part of a (later in Fi gure 8 ¬ shown) be the housing or with this rea ¬ accordingly rigidly connected. The connection of the train mechanically rigid printing character 6a, 6b is carried out at the frame part 8, the end ¬ pieces 7 and on the diagonal rod 4 just ¬ if any Festkorpergelenke. 5
The one another in pairs, and the y-axis in substantially parallel arrangement of the bar elements 6a, 6b, wherein the Anbindungs- provide the character 6a, 6b are located at opposite ends of the slide ¬ gonalstabes 4, and wherein the connection of a rod to the housing (or a so stiffly connected component) at approximately the same height (y-coordinate) comes to lie with the connection of the other rod to the diagonal bar 4, and wherein the bar connections of the rod members 6a, 6b effected at all four ends by means Festkorpergelenken 5, conditionally, that the diagonal bar without any significant resistance (ie nearly kraftefrei) can be in the x-direction verscho ¬ ben 4 relative to the housing. A torsion of the diagonal bar 4 and a shift of the diagonal bar in the y direction relative to the Ge ¬ housing opposes this structure very high resistance.
As a consequence of the structure of the connection of the drive ¬ ring 1 on the diagonal rod 4 in combination with the structural ¬ structure of the connection of the diagonal bar on the housing or as ¬ with mechanically rigidly connected parts (eg Endstuck 7, framework menteil 8), the drive ring 1 is almost kraftefrei displaceable relative to the housing in the xy-plane in every direction, but torsionally stored. Each of the drive ring 1 angrei ¬ Fende torque is determined by the inventive tangential kinematics transmitted to the housing without causing the ring is rotated significantly. The deflections caused in the Ringaufhangung are in the range of only about hun ¬ changed microns.
The frame member 8 is in this exemplary embodiment at the same time a part of the drive housing and can be given if ¬ reinforcements 16, 17 have (for example in the corners and edges). The frame part 8 can serve for fastening the Stellan ¬ drive, in particular the fixing element 12 and is therefore assumed to be stationary. As can further be seen in Figure 1, the reinforcements 16 and 17 of the Rah ¬ ment eiles 8 shots 9a and 9b torsion Fixed To ¬ supply of strip-shaped electro-mechanical (e.g., piezoelectric) bending actuators. In the frame part 8 measures shown here can not be provided to the Biegeakto- ren at their (in the frame part 8) resting end electrically contact (for example, pressure-contact pins, terminal contacts, spring contacts Bugel- etc.). Alternatively, the bending actuators can be electrically connected in the moving area and at its opposite end moving.
For receiving the moving ends of their resting ends into the receptacles 9a, 9b of the frame member 8 to be used Bie ¬ are geaktoren provided suitable Aufnahmekorper 10a, 10b, each with a sequence consisting of a solid-state joint 5, a rigid train print bar IIa , IIb and a white ¬ direct flexure bearing 5 are attached to the drive ring. 1
Figure 2 shows the drive module with inserted solid-state bending actuators 19a, 19b, which are hereinafter referred to only briefly actuator. In the exemplary configuration, the actuators 19a, mecha nically ¬ 19b fixed at its end resting stiff frame portion 8 and arranged approximately orthogonal to each other. The stiffness of the connection of the Ak ¬ gates 19a, 19b of the frame part 8 can by reinforcements 16, 17 of the frame part 8 can be increased. If an actuator 19a, 19b is electrically energized, it performs a Biegebewe ¬ supply with its moving end is substantially ausfuhrt a movement perpendicular to its longitudinal extension. The motion ¬ direction of the actuators 19a, 19b will be distinguished ¬ also with reversed direction.
Therefore, the bending actuator 19 deflects in electrical Ansteue- tion in the x-direction or resistance generated at a force in the x direction. This movement or force is mechanically rigidly transmitted through the train print bar IIa to the rigid drive ring ¬. 1 The bending actuator 19b deflected from at electrical activation ¬ shear in the y direction or generated in a resistance force in the y direction. This movement or force is mechanically rigidly transmitted through the train print bar IIb to the rigid drive ring. 1 The connection of the tension-compression point IIa, acts sawn to the Aufnahmekorper 10a, 10b and represent ¬ over to the drive ring 1 by means Festkorpergelenken 5 IIb that the bending actuators 19a, 19b completely independent of ¬ act each other and do not mutually influence Kgs ¬ nen , Thus, the actuators must especially not the work against the comparatively high mechanical stiffness of each ¬ the bending transducer. The movements of the bending transducers 19a, 19b are thus decoupled.
Is a bending actuator electrically driven, so it bends close approximately in the form of a circular arc, whereby the tangent slope of the bending line on the moving end of the bending actuator changes. This type of "rotational movement" is reliably absorbed by the Festkorpergelenke 5 Also, a Ände ¬ tion of the flex-length (relative to the driving module caused, for example, by different thermal expansion of the material ¬ lien the Tangentialkinematik, the housing and the Biegeakto ¬ ren 19a, 19b ) reliably absorbed by the train-pressure rod coupling IIa, IIb with Festkorpergelenken 5 by the letter IIa, IIb are minimal rotates, without this force or whose Wegubertragungsfunktion is remarkably impaired.
Figure 3A shows the response (deformation) of the Tangentialkine ¬ kinematics for control of bending actuator 19a to a deflection parallel to positive x-direction. The diagonal bar 4 is pushed ver ¬ by the train-pressure point 3a, 3b in the positive x-direction. As a result, it is important to note that the drive ring 1 of the x-movement of the moving end of the actuator 19a immediately follows without twisting, wherein the structure of the suspension parts of the diagonal bar 4 ensured the relevant field leadership and Flexi bilitat. It could also be an alternative
Embodiment in which the ends of the diagonal bar 4 of shown to "upper left" for "lower right", that is the reverse of those shown in Figures 1 to 8 exemplary embodiments, are diametrically opposed.
Figure 3B shows the response (deformation) of the Tangentialkine ¬ kinematics for control of bending actuator 19b to a deflection parallel to the negative y-direction. As a result, it is determined ¬ noted that the drive ring 1 of the y-movement of the moving end of the actuator 19b immediately following to be twisted without where ensured that this relevant field leadership and flexibility in the structure of the suspension parts of the ring 1 on the diagonal bar 4 ¬.
Overall, the bending actuators 19a and 19b move the drive ring 1 completely independent from each other in the x or y-direction relative to the housing. A Ringtorsion is prevented by the Tangen ¬ tialkinematik. The result is a very compact and stringently planar structure of the drive module with a very small number of simple components. Therefore the Antriebsmo ¬ dul is production-friendly. The drive module, for example, simple and inexpensive to be realized in plastic ¬ injection molding technology, and particularly advantageously, the bending actuators 19a, 19b to be injected in one operation with the drive module, whereby the number of manufacturing steps is further reduced. Incidentally, the structure of the connection of the bending actuators 19a, 19b relative to the drive ring 1 Lange changes of the elements with respect to each other (for example due to different thermal expansion of the materials used) Intercept.
To realize the tan gentialkinematischen principle associated with the drive module in the stepper motor are the Weite- ren a shaft and a play-free as possible, and rotatable mounting thereof, and a rigid mounting of the drive ¬ module is required:
4 shows a related to the Gehauserah- this men 8 suitable base element 18. It contains one at a peripheral edge of the frame part of the drive module paired To ¬ running groove 25, which ensured at the onset of the bottom element 18 in the drive module, that the bore axis a La ¬ gerbohrung congruent 26 comes to lie to the axis of the annulus bore 2 of the bovine ges. 1 The diameter of the bearing bore 26 is a cylindrical sliding surface for the shaft 39, verglei ¬ che Figure 8, coupled together forming a first clearance-free, but low-friction rotary bearing for the shaft. 39 The end face 27 of the central bearing block 28 serves as a ground flat for the shaft 39, so that a Abrollflache the shaft comes to lie on the same height with the annulus bore 2. 39
5 shows the matching to Gehauserahmen 8 and bottom element 18 cover 20, which also has a circumferential groove on its underside, which is mated to a circumferential edge of the frame part 8 of the drive module, so that during insertion of the lid 20 in the drive module, the axis of a bearing bore 29 congruent comes to lie to the axis of the annulus bore. 2 The diameter of the bearing bore 29 is coupled to a second step Cylind ¬ sliding surface to the shaft 39, which together form a second clearance-free, but low-friction rotary bearing for the shaft 39, see FIGS. 7 and 8
Figure 6 shows a suitable Bugelfeder 21. It contains a bore 30 for passage of the shaft axis, whereby sicherge ¬ provides is that this 'Migrating' may not in operation. The Bugelfeder 21 supported over surfaces 31 close to the bore-axis in the form of a Beruhrungslinie on the shaft 39 off to keep a signal generated by friction braking torque to the shaft 39 as small as possible. The far-out unte ¬ ren surfaces 32 serve for the Abstutzung Bugelfeder 21 on a lid surface. The force of the Bugelfeder 21 is suffi- dimensioned accordingly in order to keep the shaft 39 in all operating states safe abutment with the end face 27 of the bearing block 28 of the base element 18, but also as small as possible to significant friction forces which the rotation of the shaft 39 impede were to be avoided. In this way it is ensured that the Abrollflachen of drive ring 1 and shaft 39 remain localized under all operating conditions with sufficient accuracy in the z direction to each other.
Figure 7 shows a suitable shaft 39. It has two cylindrical slide bearing surfaces 33, 34 which are paired with the cylindricity ¬'s inner surfaces of the bearing bores 29, 26, and at least one cylindrical Abrollflache 35, with at least one Abrollflache 105 of the annulus bore 2 At the ¬ drive ring 1 is paired. The axial extension of the bottles surface 33 serves for connection of the respective, driven by the stepping motor element to the shaft. 39
Figure 8 shows an axial cross section along the z-axis by the drive in the assembled state. It shows another location of its components in particular. The shaft 39 is supported at two points in the form of narrow clearance fits on the basis of Gleitflachenpaare 33, 22 and 34, 23 about the z-axis rei ¬ bungsarm rotatable but mechanically rigid to translation. A suitable Bugelfeder 21 stop 39 posted for the z-direction with low friction, the shaft is fixed in cooperation with the installation surface 27th The drive module keeps at rest the Abrollflache 24 of the annulus bore 2, both concentrically and in z-direction in a suitable position relative to the Abrollfla ¬ surface 35 of the shaft. 39
By means of suitable electrical activation functions vollzie ¬ hen the bending actuators 19a, 19b, respectively, at its moving end deflections with sinusoidal or kosinusformigen temporal Ver ¬ running around the rest position, whereby the Abrollflache 24 of the annular combustion bore 2 in contact with the Abrollflache 35 of the shaft 39 is held and moved in the form of a circular sliding movement around the Abrollflache 35 of the shaft 39 and thereby caused to rotate the shaft. 39 By means of the relative Pha ¬ senlage the x- and y-displacements of the drive ring 1, the rotation direction is fixed and by means of the control frequency the rotational speed.
In the simplest case, the force transmitted from the drive ring 1 to the shaft 39 by friction. This can lead, depending on the forces acting on the shaft 39 of a load torque thus constructed actuator to slip, whereby the accuracy of the actuator is reduced. The slip is preferably reduced by the introduction of a form ¬ circuit between the Abrollflachen of drive ring 1 and shaft 39, in particular by a toothing is applied to the inner surface 24 of the drive ring 1 and the outer surface 35 of the shaft. 39 In this case, have drive ring 1 and shaft 39 preferably has a tooth difference of min ¬ least one on. This means that the toothing In ¬ nenflache 24 of the drive ring 1 comprises at least one tooth more than the outer surface 35 of the shaft. 39 Be ¬ drive ring 1 and shaft 39 such loading exaggerated within the actuator, that the toothing gerat not disengaged, the actuator ar ¬ beitet ideally slip. As a particularly preferably a cycloidal toothing of drive ring 1 and shaft 39 is considered. In the cycloidal toothing almost half of all teeth is engaged, where ¬ is transferable by a high torque between drive ring and shaft 1. 39 Located above the number of on the inner surface 24 of the drive ring 1 and the outer surface 35 of the shaft 39 teeth, a reduction of the rated ¬ lantriebs is initially set, typically in a range of 20: 1: 1 to 200 micrometers. In order to provide the actuator only one tooth, that is, the shaft 39 to rotate through the drive ¬ ring 1 by one tooth, preferably a complete period of the driving sinusoidal signal of Stel ¬ lantriebs must be passed. As for advancing must be passed around a tooth, a cycle of the drive signal, the actuator is characterized by high accuracy and high repeatability. In addition is realized by the number of teeth and the use of one cycle of at ¬ control signal per tooth high angle on solution of Stellan ¬ drive. In addition to this can be arbitrarily interpolated within egg ner period of the drive signal, In order to ensure a micro-step operation of the actuator. Thus, according to preferred constructions of the actuator provides ei ¬ ne high efficiency, a high reduction ratio, a high over ¬ transmittable torque based on the interaction of drive-ring 1 and shaft 39, slip freedom in Übertra ¬ supply of the torque, any interpolation of the rotary ¬ angle within a tooth of the shaft 39 (Mikroschrittbe ¬ operation), low drive torque fluctuations (ripple) and a low tooth flank load on drive ring 1 and shaft 39, so that also the wear is reduced.
1. Electromechanical motor, especially a piezoelectric micro-step drive, comprising: - two electromechanical drive elements (19a, 19b) having aligned Wirkrichtun ¬ gen approximately perpendicular to each other,
- a in a drive ring (1) in such a rotatably mounted shaft (39), that the drive ring (1) by a deflection of the electromechanical drive elements (19a, 19b) transferable into the respective effective direction to an immediately on the shaft (39) sliding movement is excitable, such that the shaft (39) rolls in the drive ring (1) and rotated thereby, while - the drive ring (1) by means of two mutually and ei ¬ ner of the two effective directions parallel train-pressure point (3a, 3b), each at their both ends in each case a hinge (5) which is connected to the ends of a Diagonalsta ¬ bes (4), so that the drive ring (1) rela- tively to the diagonal bar (4) in the form of a shear in the other of the two effective directions is displaceable, and
- the diametrically opposite ends of the to Minim ¬ least in sections, obliquely to the two effective directions extending diagonal bar (4) respectively by means of a parallel to the other effective direction train-push rod (6a, 6b) to its two ends, respectively a joint (5) having, in each case a fixing element (12) are angebun ¬, wherein said fixing member (12) of a rod (6a, 6b) and the connection point of the other rod (6a, 6b) to the diagonal bar (4) - and vice versa - to today along a parallel to the opposite in each case approximately one effective direction so that the diagonal bar (4) relative to the fixing elements (12) in the direction of an operative ¬ is displaceable.
2. The electromechanical motor according to claim 1, wherein the joints (5) of the train-pressure point (3a, 3b, 6a, 6b) are each formed as a flexure bearing.
3. The electromechanical motor according to claim 2, wherein the Festkorpergelenke (5) each by a Querschnittsverjun- account the train-pressure point (3a, 3b, 6a, 6b) cut in a short intervals are formed.
4. The electromechanical motor according to one of claims 1 to 3, wherein (3a 3b) arranged parallel to the one effective direction being arrange ¬ th train printing character along opposite sides (14) or halves of the drive ring (1) and each ¬ weils in a reinforcement (13, 15) of the drive ring (1) are bound by ¬, the side facing away from a diagonal bar (4) or half of the drive ring (1) is arranged.
5. The electromechanical motor according to claim 4, wherein the
Length of the between the drive ring (1) and brace member (4) at ¬ ordered, parallel to the other effective direction train-push rod (6a) is smaller than the distance between the two para ¬ Pa ra lle l to the one effective direction are arranged train-pressure Stava (3a, 3b) is.
6. The electromechanical motor according to one of claims 1 to
5, wherein the diagonal rod (4) consists of an approximately parallel with the other effective direction mounted means stucco and from end portions which are angled towards the central piece, the end sections are angled with the same sense of rotation so that the ends of the diagonal bar (4) to each other are opposite in approximately diametrically.
7. The electromechanical motor according to one of claims 1 to
6, in which the fixing element (12) arranged parallel to the other effective direction, facing away along the from the drive ring (1) side of the diagonal bar (4) extend ¬ train print bar (6b) connects, rectangular approximately at a mechanically rigid frame part (8) is attached.
Is 8. The electromechanical motor according to claim 7, wherein the frame part (8) being formed as a housing part of the stepper drive ¬.
9. The electromechanical motor according to one of claims 1 to
8, wherein the fixing element which is arranged parallel to the other effective direction, facing along the drive ring (1) side of the diagonal bar (4) extending tension-compression rod (6a) connects, in a floor element (18) and / or lid ( is integrated 20) of a housing of the stepper drive, the envisaged for connection to the fixing end of the train-push rod (6a) is provided with a (on the fixing element at ¬ bound Endstuck 7).
10. The electromechanical motor according to one of claims 1 to
9, the two electromechanical drive elements (19a, 19b) bending transducers, preferably piezoelectric bending transducers.
11. Electromechanical motor according to claim 4 and 10, wherein the reinforcements (13, 15) on the drive ring (1) in each case a parallel to the one or other direction of action arranged along one side (14) or half of the on ¬ drive ring (1 ) extending train print bar (IIa, IIb) reasonable is connected, the back having to its two ends in each case a fixed korpergelenk (5), and at whose (of the reinforcement 13, 15) end remote from each of the moving end of a perpendicular for each print bar train (IIa, IIb) is arrange ¬ th, along one side (14) or half of the drive ring (1) extending the bending transducer (19a, 19b) is coupled.
12. Electromechanical motor according to claim 10 or 11, wherein at least the frame member (8), the drive ring (1), the train-pressure point (3a, 3b, 6a, 6b, IIa, IIb) and the diagonal rod (4) form a einstuckig gefer ¬-saturated in the plastic injection molding technology driving module, wherein the bending transducers (19a, 19b) are injected into the drive module.
13. The electromechanical motor according to one of claims 1 to 12, in which an approximately cuboidal housing with a floor element (18) and a cover (20) is provided, in the floor element (18), a central bearing block (28) with an abutment surface (27 a second bearing bore (29) is provided for the shaft (39)) and with a first bearing bore (26) and in the cover (20), and wherein the fixing elements (12) arranged on the housing and fixed to or integrated, that the at least one cylindrical Abrollflache (35) of the shaft (39) in an associated Abrollflache (24) of an annular bore (2) of the drive ring (1) can roll.
14. The electromechanical motor according to claim 13, wherein the shaft (39) is formed with a disc-shaped central piece, the first annular end face rests on the bearing block (28) and the cylindrical From ¬ roll flat (35) whose circumferential surface of the shaft (39) ,
15. The electromechanical motor according to claim 14, provided in which to ensure the fixing in the z direction of the axis of Wel ¬ le (39) having a bore (30) for passage of the shaft (39) Bugelfeder (21) is provided, which is ei ¬ nerseits on the second annular end surface of the failed ¬ benförmigen stucco means of the shaft (39) and on the other hand so braced with the lid on one surface of the lid, that the rotation of shaft (39) is not significantly impeded.
16. The electromechanical motor according to one of claims 1 to 15, wherein the formschlussigen power transmission to the In ¬ nenflache (24) of the ring bore (2) of the drive ring (1) and to the associated Abrollflache (35) of the shaft (39) Ver is applied ¬ toothing, especially a cycloidal toothing.
PCT/EP2008/054909 2007-05-18 2008-04-23 Electromechanical motor, especially piezoelectric microstepper drive WO2008141886A1 (en)
DE200710023217 DE102007023217B4 (en) 2007-05-18 2007-05-18 Electromechanical motor, especially a piezoelectric micro-step drive
DE102007023217.0 2007-05-18
CN 200880016520 CN101681987B (en) 2007-05-18 2008-04-23 Electromechanical motor, especially piezoelectric microstepper drive
EP20080736489 EP2149164B1 (en) 2007-05-18 2008-04-23 Electromechanical motor, especially piezoelectric microstepper drive
US12600787 US8004149B2 (en) 2007-05-18 2008-04-23 Electromechanical motor, especially a piezoelectric microstepper drive
JP2010508770A JP5130356B2 (en) 2007-05-18 2008-04-23 Electromechanical motor, especially a piezoelectric micro-step drive device
DE200850003013 DE502008003013D1 (en) 2007-05-18 2008-04-23 Electromechanical motor, especially a piezoelectric micro step drive
WO2008141886A1 true true WO2008141886A1 (en) 2008-11-27
ID=39591342
PCT/EP2008/054909 WO2008141886A1 (en) 2007-05-18 2008-04-23 Electromechanical motor, especially piezoelectric microstepper drive
US (1) US8004149B2 (en)
EP (1) EP2149164B1 (en)
JP (1) JP5130356B2 (en)
CN (1) CN101681987B (en)
DE (2) DE102007023217B4 (en)
WO (1) WO2008141886A1 (en)
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CN101681987B (en) 2013-10-16 grant
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