DE102010029278A1 - Device for detecting angular accelerations toward rotation degree of freedom and for applying rotational torques or rotational angles toward rotation degree of freedom, has transducer attached to surface of strip material - Google Patents

Abstract

The device has a spiral spring (1) arranged in a main extension plane around a normal axis, where a strip material (2) is wound along the main extension plane. The strip material has a fixed end (7) fixed at a base and a free end (6) engaged at a device part in relation to the base. A mechanical electrical transducer (4) is attached to one of surfaces (3) of the strip material in a main extending direction parallel to the normal axis.

Description

TECHNICAL FIELD OF THE INVENTION

The invention relates to a device having at least one spiral spring and the further features of the preamble of independent claim 1.

More particularly, the present invention relates to such a device which is useful as a rotational degree of freedom sensor, again, in particular, to detect angular accelerations in the direction of rotational freedom. Also, the detection of rotation angles in the direction of the rotational degree of freedom may be of interest. In parallel, the present invention also relates to such devices that are suitable as a rotational degree of freedom actuator to apply torques or rotation angle in the direction of rotation degree of freedom.

However, the present invention is expressly not limited to those devices that cover only one rotational degree of freedom. Rather, both multiple rotational degrees of freedom as well as additional translational degrees of freedom can be covered.

STATE OF THE ART

From the CH 684 029 A5 a sensor for measuring angular acceleration is known, having the features of the preamble of independent claim 1. The sensor is structured from a silicon carrier consisting of a substrate, an insulating layer applied thereto and a polysilicon layer applied to the insulating layer. From the polysilicon layer, an anchor point is structured, which is firmly connected to the substrate via the insulating layer. From this anchor point as the center two spirals run into each other, which are formed only in the polysilicon layer and are not connected via the anchor point with the substrate and thus are like coil springs movable. In each case on the outer turns of the spirals movable masses are also formed only in the polysilicon layer, which are arranged in a star shape to the anchor point. You have on two sides comb-shaped finger structures. Likewise in a star shape around the anchor point, fixed electrodes are arranged between the movable masses and are connected to the substrate and / or a frame. The fixed electrodes also have comb-shaped finger structures. The finger structures of the movable masses and the finger structures of the fixed electrodes engage each other. These finger structures together form interdigital capacitors or electrostatic reluctance drives, which can be used for position control but also for signal detection. A signal detection in this structure is also possible with arranged on the spirals piezoresistors. With this sensor, angular accelerations can be detected around an axis perpendicular to the carrier surface. The Archimedean spirals act like coil springs, which are stretched or compressed depending on the rotors, whereby the position of the movable masses is changed with respect to the fixed electrodes, which leads to changes in the electrical conditions of the interdigital capacitors. Due to the meshing finger structures of the movable masses and of the stationary electrodes, this known sensor is fundamentally only suitable for relatively small deflections of the movable masses. Moreover, its mobile masses are exclusively inert masses, which are detected against angular acceleration of the anchor point. Also, due to its miniaturized design, the known sensor, for example, not suitable for transmitting larger absolute forces between its anchor point and the moving masses.

OBJECT OF THE INVENTION

The invention has for its object to provide a device with the features of the preamble of independent claim 1, which is suitable as a sensor and actuator for larger angles of rotation and forces.

SOLUTION

According to the invention, the object of the invention is achieved by a device having the features of independent patent claim 1. Preferred embodiments of the new device are defined in the dependent claims 2 to 18. The claim 19 relates to the use of the new device as a sensor at least for rotational movements and the claim 20 relates to the use of the new device as an actuator, at least for rotational movements.

DESCRIPTION OF THE INVENTION

In the new device, at least one mechanical-electrical converter engages at least one surface of the strip material that runs parallel to the axis in its one main extension direction and that winds around it in its other main extension direction. Such a mechanical-electrical converter converts mechanical stresses into electrical signals and vice versa. A piezoresistor does not fall within this definition, even if the preferred embodiment of the mechanical-electrical transducer is a piezoelectric transducer. By the mechanical-electrical converter in the device according to the invention on the parallel to the axis and running around the axis winds around surface of the strip material, it has a high sensitivity to the rotations of the device supported by the coil spring device part. Thus, both rotational movements of the device part relative to the base can be detected accurately and given the stiffness of the coil spring specific torques and thus angular accelerations are assigned, as well as in the opposite direction rotational movements of the device part relative to the base are deliberately caused. Although the prevailing force-displacement ratios affect these two sensitivities in opposite directions, in known mechanical-electrical transducers the distance traveled with increasing voltage is usually very small, so that a massive travel magnification under defined conditions only for balanced conditions and not ensures that the mechanical-electrical transducer as a sensor against small movements would be insensitive.

In the new device, it is preferable that the first end fixed to the base is the outer end of the strip material and the second end engaging the device part is the inner end of the strip material. The coil spring thus winds around the resiliently supported device part.

Further, it is preferred in the new device, when the second end is fixed to the device part or at least via a solid-state joint on the device part attacks to create a play and dead-point connection here.

In the new apparatus, the mechanical-electrical converter has a working direction curved along the respective surface of the strip material around the axis. In this case, it is preferable for the mechanical-electrical converter to have connecting electrodes which extend along its working direction and thus along the surface of the strip material, against which the mechanical electrical transducer acts. It is also possible to form at least one of the terminal electrodes of the piezoelectric transducer by the strip material or to electrically contact at least over the strip material, if this is electrically conductive. The latter is the case when the strip material is a metal or a conductive carbon fiber composite. However, the strip material does not have to be electrically conductive, but may also consist of an electrically insulating plastic, optionally with reinforcement, for example, by glass fibers.

In the new device, the mechanical-electrical converter can engage one of the two outer surfaces of the strip material and only on this surface. In another preferred embodiment, the mechanical-electrical transducer engages two opposing inner surfaces of the strip material. In this embodiment of the new device, for example, the d ₁₅ effect of piezoelectric materials can be exploited. Preferably, in this embodiment of the new device, the mechanical-electrical converter extends in the region of the neutral fiber of the strip material.

It can also attack several mechanical-electrical converter on the same or different surfaces of the strip material. It is preferred in this case that the plurality of mechanical-electrical transducers are distributed over the extent of the strip material between the base and the device part in order to act on different areas of the strip material or to detect deformations of these different areas of the strip material.

It is particularly preferred if the mechanical electrical transducer or transducers are extended over at least 25%, more preferably over at least 33%, and most preferably over at least 50% of the extent of the strip material between the base and the device part. Ideally, they are at least substantially extended over the entire extent of the strip material between the base and the device part.

As a result, if a plurality of mechanical-electrical transducers are provided on both outer surfaces of the strip material, the working area can generally be expanded with respect to rotational movements of the device part relative to the base, compared to the case in which the transducers are present only on one of the outer surfaces, because often mechanical electrical converters can not be stretched and shortened in the same way by electrical control.

With regard to the number of turns of the coil spring about the axis, a minimum number of one turn, preferably of 2 turns, must be observed in order to initiate as pure as possible a rotary movement of the device part about the axis by the attack of the mechanical-electrical transducer on the strip material of the spiral spring and vice versa. On the other hand, it should be noted that, in a larger number of turns of the coil spring rotational movements of the device part relative to the base in ever smaller local deformations of the strip material of the coil spring express. In addition, with the same rigidity of Band material, the overall stiffness of the support of the device part is always lower. Therefore, a significantly larger number of turns of the coil spring is usually not favorable.

Regarding the shape of the coil springs, an Archimedean spiral around the axis is preferred. However, other spiral shapes such as logarithmic, Fermatsche and hyperbolic spiral shapes may be used.

In the new device, if it is to be used as a sensor or actuator for pure rotational movements, which is a preferred application, the device part may be rotatably mounted on the base in a rotary bearing about the axis. Thus, the device part has only one rotational degree of freedom about the axis.

In principle, however, the device part can additionally also have at least one translational degree of freedom with respect to the base running parallel to the main extension plane of the spiral spring. Even with only one spiral spring and several mechanical-electrical transducers arranged thereon, this degree of translational freedom can also be controlled or covered by sensors. However, it is preferred if at least 2, preferably at least 3, and most preferably at least 4 helical springs wound into one another in their common main extension plane are provided for triggering or detecting movements in the direction of the at least one translational degree of freedom with mechanical-electrical transducers acting on their band materials , which are fixed in different angular ranges about the axis with its one end to the base and engage in different angular ranges about the axis with its other ends to the device part. The movements of the device part in the direction of translational degrees of freedom then typically have different effects on the individual coil springs and thus the mechanical-electrical converters arranged thereon, or vice versa.

In the new device, the base on which the first end of the strip material of the spiral spring is fixed, in a plane orthogonal to the main extension plane of the coil spring via a further spiral spring with at least one mechanical-electrical converter in a further basis be supported. This corresponds to a cascaded structure for covering various degrees of freedom of movement, in particular rotational degrees of freedom with the new device.

In principle, however, it is also possible for at least two, preferably three spiral springs with mutually orthogonal main extension planes to be wound into one another, with the first ends of their strip materials being fixed to the same base and the second ends engaging their strip materials on the device part. It is understood that the deformations of the individual coil springs are not independent of each other, but this can be taken into account in the evaluation of the signals from the mechanical-electrical converters or their control.

Advantageous developments of the invention will become apparent from the claims, the description and the drawings. The advantages of features and of combinations of several features mentioned in the introduction to the description are merely exemplary and can come into effect alternatively or cumulatively, without the advantages having to be achieved by embodiments according to the invention. Further features are the drawings - in particular the illustrated geometries and the relative dimensions of several components to each other and their relative arrangement and operative connection - refer. The combination of features of different embodiments of the invention or of features of different claims is also possible deviating from the chosen relationships of the claims and is hereby stimulated. This also applies to those features which are shown in separate drawings or are mentioned in their description. These features can also be combined with features of different claims. Likewise, in the claims listed features for further embodiments of the invention can be omitted.

BRIEF DESCRIPTION OF THE FIGURES

In the following the invention will be further explained and described with reference to preferred embodiments shown in the figures.

1 shows a coil spring extending only over an arc angle of 90 ° with arranged thereon mechanical-electrical converter and the deflection of a free end of the coil spring when driving the mechanical-electrical converter to elongation.

2 is a 1 corresponding representation of a over a arc angle of 180 ° extending coil spring.

3 is a 1 corresponding representation of a over a arc angle of 270 ° extending coil spring:

4 is a 1 corresponding representation of a over a arc angle of 360 ° extending coil spring.

5 is a 1 corresponding representation of a over a arc angle of 540 ° extending coil spring.

6 is a 1 corresponding representation of a corresponding over an arc angle of 720 ° or two turns coil spring.

7 is an embodiment of the new device with a two-turn coil spring and a plurality of mechanical-electrical transducers disposed therein.

8th is an embodiment of the novel device with a two-turn coil spring and integrated therein in the region of its neutral fiber mechanical-electrical transducers.

9 shows a basic position of an embodiment of the new device with two each two turns having, intertwined spiral springs and the effect of the same direction control by attached to them mechanical-electrical converter.

10 shows the arrangement according to 9 with opposite control of the two coil springs.

11 shows an embodiment of the new device with three extending over an arc angle of 270 ° coil springs.

12 shows an embodiment of the new device with four, each extending over almost one turn, spiral springs inturned upon control of the coil springs on a first translational movement of the device part supported by them.

13 shows the arrangement according to 12 upon control of the coil springs on a second translational movement of the device part supported by them.

14 shows the arrangement according to 12 in a control of the coil springs on a superposition of the translational movements according to 12 and 13 ,

15 shows an embodiment of the new device with four coil springs, each having two windings when driven to a rotational movement of the device part supported by them.

16 Sketches an Archimedean spiral.

17 outlines a logarithmic spiral.

18 outlines a Fermatian spiral.

19 outlines a hyperbolic spiral.

20 outlines a cascaded arrangement of several new devices with mutually orthogonal rotational degrees of freedom of the individual cascade stages; and

21 outlines an arrangement of three mutually orthogonal major planes extending, spiraling spiral springs, which engage with their inner ends on the same device part and support against a base, not shown here.

DESCRIPTION OF THE FIGURES

In the 1 shown spiral spring 1 is from a band material 2 bent over a bend angle of 90 °. On an outer surface 3 of the band material 2 is a mechanical-electrical converter 4 in the form of a piezoelectric transducer 5 arranged. Shown is next to the initial position of the coil spring 2 the deflection of a second, here free end 6 of the band material 3 opposite a first, fixed here end 7 , The deflected end 6 ' is with respect to the radius of curvature of the coil spring 2 deflected substantially radially inward.

At the coil spring 1 according to 2 , according to those 1 matches, except that the strip material 2 over an arc angle of 180 ° around the axis drawn here 8th winds, causes the control of the mechanical-electrical converter 4 on an increase in its length, although still a movement of the second end 6 to the axis 8th towards, but increasingly in the circumferential direction about the axis 8th , This becomes even clearer when the spiral spring winds over an arc angle of 270 ° 1 according to 3 ,

When spiraling over a full turn spiral spring 1 according to 4 almost exclusively results in a deflection of the free end 6 in the circumferential direction.

At about 1.5 turns around the axis 8th extending spiral spring 1 according to 5 Although again comes a slight radial portion of the deflection of the free end 6 added; at the spiral spring extending over two full turns 1 according to 6 shifts the free end 6 upon activation of the mechanical-electrical converter on its outer surface 3 but again almost exclusively in the circumferential direction.

7 outlines a device 9 that according to the 1 to 6 deliberately exploited explained effect. Here is the coil spring 1 with her first end 7 at a base 10 set while her second end 6 on a device part 11 attacks, around the axis 8th rotatable relative to the base 10 is stored. It is between the end 6 and the device part 11 a not shown here in detail solid state joint 12 educated. On the outward facing outer surface 3 of the band material 2 Here are two mechanical-electrical converters 4 in the form of piezoelectric transducers 5 in different sections of the strip material 2 arranged. Two more mechanical-electrical converters 4 in the form of piezoelectric transducers 5 are in different sections of the strip material 2 on its inwardly facing outer surfaces 13 arranged. The on the outer surfaces 3 and 13 attacking mechanical-electrical converter 4 are alternately driven to the device part 11 in opposite directions around the axis 8th to rotate, or the electrical signals emitted by them are used to a rotational movement of the device part 11 opposite the base 10 to capture, for example, an angular acceleration about the axis 8th take.

In 8th is outlined that the one or more mechanical-electrical converters 4 also in the band material 2 integrated and there on inner surfaces 14 and 15 of the band material 2 can attack, for example, when it comes to piezoelectric transducers 5 which are driven by a d ₁₅ effect. Preferably, the piezoelectric transducers extend 5 in this case in the area of the neutral fibers of the strip material 2 ,

9 outlines an embodiment of the device 9 with two spiral springs 11 and indicates a rotation of the device part supported by them 11 clockwise when both coil springs 1 be driven in the same direction to a "unwinding" of the common axis by mechanical-electrical converter not shown here.

Opposite shows 10 the effect of opposing control of the two coil springs 1 the device according to 9 , where the spiral spring 1 whose ends in the illustrations on the left are just as controlled as in 9 and the other coil spring 1 on a "winding up" on the common axis. This results in a displacement of the device part 11 in the illustration of the figures down.

11 outlines the support of the device part 11 opposite the base 10 around the axis 8th by total 3 intertwined, each with an arc angle of 270 ° around the axis 8th extending coil springs 1 at the device 9 ,

12 shows a device 9 with a total of four coil springs 1 and arranged thereon mechanical-electrical transducers 4 for supporting the device part 11 , In this case, such a coordinated control of the coil springs 11 , each extending over an arc angle of about 270 °, indicated that a translational movement of the device part 1 1 results in the vertical direction of the figure.

13 sketched at the device 9 according to 12 such a controlled control of the coil springs 1 in that the device part 11 moved in a horizontal direction of the figure translational.

14 outlines the superimposition of the control of the coil springs 1 the device 9 according to 12 and 13 , This results in a translational movement of the device part 11 in the diagonal direction of the figure.

In contrast, outlined 15 again the effect of a co-directional control of all coil springs 1 at the device 9 according to the 12 to 14 , in a pure rotary motion of the device part 11 results.

Of the in the 16 to 19 Spiral shapes shown for the new device in 16 reproduced Archimedean spiral for the formation of the coil springs particularly preferred.

20 outlines a cascaded arrangement of devices 9 with coil springs 1 , wherein an inner device 9 that the device part 11 around an axis perpendicular to the plane of the drawing 8th towards a base 10 supports, with this base 10 turn to one in the 11 horizontally extending axis via two devices 9 ' at a base 10 ' supported, in turn, via two more devices 9 '' around a vertical axis at a base 10 '' is supported. The devices 9 . 9 ' and 9 '' detect each rotational movements about one of the three orthogonal axes 8th or serves to control the device part 11 on such rotational movements.

In the device 9 according to 21 are three coil springs 1 whose main extension planes are aligned orthogonal to each other, wound into each other and jointly supported the same device part 11 opposite to the base not shown separately from where their ends 7 are fixed. It is understood that here the individual degrees of freedom of movement, in particular the three rotational degrees of freedom are not decoupled from one another, ie a rotation of the device part 11 relative to the base about an axis leads to the deformation of all three coil springs 1 even if the rotation is around one Axis takes place perpendicular to the main extension plane of one of the coil springs 1 runs.

Experimental testing of the new device revealed a largely linear relationship between the voltage at which piezoelectric transducers were driven on the coil spring and the angle about the axis around a rigid axis 8th mounted device part 11 could be twisted. With relatively low drive voltages of 400 volts, even with the piezoelectric transducers not extending over the entire extent of the strip material between the base and the device part, the device part could be statically rotated by 5 °, with an angular resolution of 0.02 ° being achieved. With dynamic operation in the range of the resonance frequency of the arrangement of 12 Hertz a dynamic rotation by 20 ° could be achieved. The corresponding experimental setup included a coil spring with two turns. Variations in the resonant frequency of the arrangement are possible via the stiffness of the coil springs in large areas.

LIST OF REFERENCE NUMBERS

1

spiral spring

2

band material

3

outer surface

4

mechanical-electrical converter

5

piezoelectric transducer

6

second end

7

first end

8th

axis

9

contraption

10

Base

11

device part

12

Solid joint

13

outer surface

14

inner surface

15

inner surface

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• CH 684029 A5 [0004]

Claims (20)

Contraption ( 9 ) with at least one spiral spring ( 1 ) in a main plane of extension about an axis normal to the main plane of extension ( 8th ) winding strip material ( 2 ), with a first end ( 7 ) of the strip material ( 2 ) at a base ( 10 ), with a second end ( 6 ) of the strip material ( 2 ) on a device part ( 11 ) and wherein the device part ( 11 ) compared to the base ( 10 ) at least one degree of freedom of movement for rotations about the axis ( 8th ), characterized in that at least one in its one main extension direction parallel to the axis ( 8th ) and in its other main extension direction winding around this surface ( 3 . 13 . 14 . 15 ) of the strip material ( 2 ) at least one mechanical-electrical converter ( 4 ) attacks. Contraption ( 9 ) according to claim 1, characterized in that the first, at the base ( 10 ) fixed end ( 7 ) the outer end of the strip material ( 2 ) and the second, on the device part ( 11 ) attacking end ( 6 ) the inner end of the strip material ( 2 ) of the spiral spring ( 1 ). Contraption ( 9 ) according to claim 1 or 2, characterized in that the second end ( 6 ) on the device part ( 11 ) or via a solid-state joint ( 12 ) on the device part ( 11 ) attacks. Contraption ( 9 ) according to at least one of the preceding claims, characterized in that the mechanical-electrical converter ( 4 ) a piezoelectric transducer ( 5 ). Contraption ( 9 ) according to at least one of the preceding claims, characterized in that the mechanical-electrical converter ( 4 ) one along the respective surface ( 3 . 13 . 14 . 15 ) around the axis ( 8th ) has curved working direction around. Contraption ( 9 ) according to at least one of the preceding claims, characterized in that the mechanical-electrical converter ( 4 ) Has terminal electrodes which extend along its working direction. Contraption ( 9 ) according to at least one of the preceding claims, characterized in that the mechanical-electrical converter ( 4 ) on one of the two outer surfaces ( 3 . 13 ) of the strip material ( 2 ) attacks. Contraption ( 9 ) according to at least one of the preceding claims, characterized in that the mechanical-electrical converter ( 4 ) on two opposing inner surfaces ( 14 . 15 ) of the strip material ( 2 ) attacks. Contraption ( 9 ) according to claim 8, characterized in that the mechanical-electrical converter ( 4 ) in the region of the neutral fiber of the strip material ( 2 ) runs. Contraption ( 9 ) according to at least one of the preceding claims, characterized in that a plurality of mechanical-electrical transducers ( 4 ) about the extent of the strip material ( 2 ) between the base ( 10 ) and the device part ( 11 ) are arranged distributed. Contraption ( 9 ) according to at least one of the preceding claims, characterized in that the one or more mechanical-electrical transducers ( 4 ) over at least 25%, preferably over at least 33% and most preferably over at least 50% of the extent of the strip material ( 2 ) between the base ( 10 ) and the device part ( 11 ) are extended. Contraption ( 9 ) according to at least one of the preceding claims, characterized in that the spiral spring ( 1 ) one to three, preferably one and a half to two and a half, and most preferably two turns of the strip material ( 2 ) around the axis ( 8th ) having. Contraption ( 9 ) according to at least one of the preceding claims, characterized in that the strip material ( 2 ) of the spiral spring ( 1 ) like an Archimedean spiral around the axis ( 8th ) is wound. Contraption ( 9 ) according to at least one of the preceding claims, characterized in that the device part ( 11 ) in a pivot bearing about the axis ( 8th ) rotatable on the base ( 10 ) is stored. Contraption ( 9 ) according to at least one of the preceding claims, characterized in that the device part ( 11 ) at least one parallel to the main extension plane of the spiral spring ( 1 ) translational degree of freedom from the base ( 10 ) having. Contraption ( 9 ) according to at least one of the preceding claims, characterized in that at least two, preferably at least three and most preferably at least four helical springs wound into one another in their common main extension plane (US Pat. 1 ) with on their band materials ( 2 ) attacking mechanical-electrical transducers ( 4 ) are provided, the in different angular ranges around the axis ( 8th ) with their one ends ( 7 ) at the base ( 10 ) and in different angular ranges about the axis ( 8th ) with their other ends ( 6 ) on the device part ( 11 attack). Contraption ( 9 ) according to at least one of the preceding claims, characterized in that the base ( 10 ), at which the first end ( 7 ) of the strip material ( 2 ) of the spiral spring ( 1 ) is fixed in a direction orthogonal to the main extension plane of the spiral spring plane via a further spiral spring ( 1 ) with at least one mechanical-electrical converter ( 4 ) on another basis ( 10 ' . 10 '' ) is supported. Contraption ( 9 ) according to at least one of the preceding claims, characterized in that at least two, preferably three coil springs ( 1 ) with mutually orthogonal main extension planes and with at least one mechanical-electrical converter ( 4 ) are wound into each other, wherein the first ends ( 7 ) whose strip materials ( 2 ) at the same base ( 10 ) and the second ends ( 6 ) whose strip materials ( 2 ) on the device part ( 11 attack). Use of a device ( 9 ) according to at least one of the preceding claims as a sensor at least for rotational movements of the device part ( 11 ) around the axis ( 8th ) compared to the base ( 10 ). Use of a device ( 9 ) according to at least one of the preceding claims as an actuator at least for rotational movements of the device part ( 11 ) around the axis ( 8th ) compared to the base ( 10 ).

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