DE102014104327A1 - Actuator device, use of the actuator device and system with such an actuator device - Google Patents

Abstract

The invention relates to an actuator device comprising a magnetic shape memory alloy material (MSM) designed to cooperate with an actuator and an expansion movement along an expansion direction in response to an induced magnetic flux expansion unit (10) along a longitudinal axis determined by the expansion direction on the control partner can be aligned and at one end an effective portion (14, 18) for exerting a force on the control partner, wherein the expansion unit at the other end, in particular the active portion opposite, biasing and / or spring means (22, 24) are assigned so that in one of the magnetic flux unbeaten operating state, the expansion unit can exert a force, in particular a pushing, adjusting and / or holding force on the control partner and / or can dampen the expansion unit.

Description

The present invention relates to an actuator device according to the preamble of patent claim 1. Furthermore, the present invention relates to a use of such an actuator device and a system comprising such actuator device in conjunction with a control partner, said arrangement being associated with return means for the expansion unit.

An actuator device according to the preamble of the main claim is for example from the EP 1 760 796 B1 and describes the use of an expansion element made of a magnetic shape memory alloy material (MSM = Magnetic Shape Memory), hereinafter equivalently used with magnetic shape memory alloy (FGL = shape memory alloy) for an intended actuator or positioning functionality. Concretely, to effect such an actuator function, an MSM (FGL) crystal body, usually made on the basis of a NiMnGa alloy, is controlled by a magnetic field generated by a current-supplied coil. In response to such magnetic flux (typically applied on the shell side), the expansion element of the MSM crystal body undergoes an expansion movement, the stroke of which generally proceeds in a direction perpendicular to the direction of flux with the magnetic flux. This expansion movement then acts via a provided on the end of the crystal effective portion (such as a suitable plane surface) on a along the expansion or adjustment direction attributable plunger as a possible control partner, which then performs the intended setting task in the desired manner.

MSM-based actuators have fast switching times and high switching cycles (so-called switching cycle number, which for a crystal can include more than 400 million expansion processes). For the actuator used and expandable in response to the initiated magnetic flux MSM expansion units allow a typical expansion stroke in the order of about 4% to 6% based on a direction of extension of the crystal body along the direction of expansion (in the unexpanded state), which usually in Supported in this direction long stretched crystal body for maximum Hubausnutzung at its opposite end of the active section (front side) is supported or fixed there; As an abutment for such a support, for example, a stationary, stationary housing portion of the actuator device can serve.

In a direct constructive-mechanical relationship with the described positioning functionality of the expansion unit is the possible use of generic actuator devices that are used for gripping or touching carry a gripping object or the like body. For example, with the purpose of realizing a robotics functionality allows a generic actuator device, typically realized as a plurality of cooperating actuator devices of the generic type to replace traditionally known electromotive or pneumatic actuators for gripping or driving functionality, again with the discussed advantages of short switching times and high, low-wear switching cycles. In that regard, the gripping object to be touched and taken along would then fill the role of the superordinate positioning partner and be mechanically contacted by the (at least one) actuator device for gripping or entrainment purpose.

MSM crystal bodies expandable in the generic manner by a magnetic flux have the property of not performing any automatic (mechanical) contraction back to the non-expanded (contracted) state after completion of the magnetic flux; rather, the expansion unit initially remains in its expanded state without further mechanical interference. In order then to bring about a return to the contracted initial state, it is to be assumed as known from the prior art to associate with the expansion unit return means, which cause this contraction after completion of the expansion; Such return means are known, for example, in the form of return springs acting counter to the direction of expansion, alternatively, for example, as oppositely expandable MSM crystal bodies.

When using a generic actuator device for gripping purposes, that is, in response to a control and thus a generated magnetic flux caused expansion movement of the expansion unit, which touches a gripping object for gripping or entrainment, occurs accordingly to the effect that with a termination of the magnetic field generation (According to a termination of the magnetic flux), the expansion unit or a potentially interposed to the gripping object ram unit can no longer exert force on the gripping object. Even if, in the absence of restitution, the expansion unit remains in its expanded position, no further force is generated along the direction of expansion; Consequence is that in a gripping operation (such as in the robotics context) the gripping object can no longer be reliably held and possibly inadvertently detached from the actuator device.

Another problem of the generic actuator technology, especially with the Expansion unit cooperating and this after completion of the magnetic flux recirculating reset unit, is that especially at high switching speeds and correspondingly fast or heavily loaded force resetting the expansion unit disadvantageous bouncing or swinging (overshoot) of the expansion unit and restoring unit formed (about return spring) system , A possible disadvantageous consequence is that the expansion unit briefly releases from its (rear) abutment and is then pushed by the return means against this abutment, with possible adverse consequences for the (usually brittle) crystal material of the MSM expansion unit and accordingly for life and service life ,

Object of the present invention is therefore to improve the actuator according to the preamble of the main claim in terms of their operating characteristics, on the one hand for a potentially permanent, continuous application of force (realized as a gripping object) Stellpartners to provide, even if no magnetic flux with the Magnetic flux (more) is carried out, which alike according to the object, the dynamic properties of the generic actuator device, in particular in cooperation with a provision of the expansion unit in the contracted initial state causing return means can be improved without it to adverse dissolution, impact and / or vibration effects of Expansion unit based on an abutment opposite the actuator abutment comes.

The object is achieved by the actuator device having the features of the main claim; advantageous developments of the invention are described in the subclaims. In the context of the invention, further protection is claimed for the use of such an actuator device according to the invention as a gripping and / or entraining device (or, in the context of a gripping or entrainment device, in conjunction with further actuator devices according to the invention). In the context of the present invention, protection is also claimed for a system having the actuator device according to the invention and an actuating partner, wherein the system is associated with return means for returning the expansion unit to a contracted initial position.

In accordance with the invention advantageously, the expansion unit, the active section for the control partner opposite end, biasing and / or spring means are assigned so that in a unbound by the magnetic flux operating state of the expansion unit, this can exert a force on the control partner. In the case of a use of the invention to take away or gripping a gripping object as a control partner in this way a pushing or holding force will continue to act on the gripping object, even if (with magnetic flux deactivated) no (further) expansion of the crystal takes place and accordingly from the crystal itself no further force can act on the control partner. This function is then taken over by the other end acting biasing or spring means, which provide the invention for a continued push or holding force. Useful and advantageous is to select or design these biasing and spring means so that their spring force (slightly) below the force required for (purely mechanical) compression of the MSM element (without field exposure). This force results from the so-called twinning stress of the material. Consequently, for a high holding power of the system, it is meaningful to use targeted MSM material with increased Twinning stress, while one would otherwise strive to use material with the lowest possible Twinning stress to increase efficiency and minimize the magnetic field. Accordingly, it comes within the scope of the preferred realization of the invention, since the material with increased twin voltage (equivalent to increased switching field) must be moved by the magnetic field, to optimize between high thrust and holding force on the one hand and fast switching / compact actuator due to low switching field on the other ,

Again, advantageously and according to the invention, these biasing or spring means further effect that in the case of dynamic expansion and contraction (by further education and advantageous associated return means, such as a return spring) resulting vibrations or bounce effects can be effectively damped (cushioned): namely, occurs in Case of recovery by restoring means after expansion, a (typically short and thus strongly kraftbeaufschlagte) contraction, this does not lead, as disadvantageous in the prior art, to a potentially materially harmful impact of MSM crystal body on the active section opposite abutment, but rather take the here According to the invention provided biasing or spring means such a return and impact pulse, so that a soft striking or reset takes place (especially if the biasing or spring means so used have only a limited stroke n and at the other end in turn stationary or stationary supported by a suitable housing bottom or the like. Abutment section).

It is provided in the context of preferred developments of the invention and advantageous, the biasing or spring means according to the invention as a compression spring, more preferably as a spiral spring to realize from a suitable spring material; alternatively, the biasing means may also be realized as a potentially solid body of elastomeric material such as rubber, silicone, or other plastic material; a concrete emphasis in the context of the invention, such as impact attenuation and / or continued application of force to the expansion unit, then decides on a respectively suitable mechanical-structural implementation of the biasing or spring means according to the invention.

In this case, it is also possible to realize this biasing or spring means according to the invention in the form of a plurality of (single) spring or damping elements, which then according to a respective application necessary effective strokes and the like. Randbedingungen also a layered arrangement of these Single elements may be advantageous.

In the context of a preferred embodiment of the invention, it is to associate the biasing or spring means means to a stroke limitation of the spring or Dämpfungshub counter to the expansion movement.

The advantage of this further development measure is that in this way a defined abutment or stop position can be ensured, which nevertheless is damped by the biasing or spring means according to the invention. In the practical implementation, it is particularly favorable to realize this stroke limiting means by a stop or shoulder for the pretensioning or spring means (for example, suitable jacket or radial edge side); Additionally or alternatively, such a stroke limitation can also be effected by a corresponding stop for the expansion unit itself.

It is also advantageous within the scope of the invention, according to further development, to assign own pretensioning means to the pretensioning or spring means, which are advantageously set up in the form of a mechanical length limitation or length device to a predetermined length and compression dimension of the pretensioning or spring means. In this way, the biasing or spring effect (also: damping effect) of the biasing or spring means according to the invention can be controlled, whereby it has proved to be preferred mechanically-constructive, the length limitation by a suitable stop, shoulder or projection for Attack by the Vorspann- or spring means to realize.

As a result, by means of these inventive measures, an actuator device which is improved with regard to both its damping and dynamic properties as well as with regard to continued application of force to / from an actuator is suitable for a large number of positioning, gripping and / or driving applications and in the manner according to the invention either in isolation, as a system in combination with a control partner, can be converted into improved devices or systems.

Further advantages, features and details of the invention will become apparent from the following description of preferred embodiments and from the drawings; these show in:

1 a schematic longitudinal sectional view through an actuator device according to a first preferred embodiment, as it can be advantageously used as an assembly in the context of a gripping and / or driving device, and

2 a schematic longitudinal sectional view through an actuator device according to a second embodiment of the invention, in which case the expansion unit are formed as a spring formed return means.

The 1 illustrates in the schematic longitudinal sectional view of the actuator according to a first preferred embodiment of the invention. An elongated MSM crystal body (in the plane of the figure in the upward direction) 10 as an expansion unit acts in an otherwise known manner together with a radially symmetrical enclosing coil unit 12 such that when they are energized, a magnetic flux (horizontally extending in the plane of the figure) forms the expansion unit 10 penetrates. At a front-side effective section 14 acts the expansion unit 10 together with a ram unit 16 , which with a front engagement end 18 for interacting with an external positioning partner (not shown), for example a gripping object which is to be touched mechanically and thus gripped, from an upper housing section 20 the device can be moved out. Bottom side, ie the active section 14 along the (vertical) longitudinal axis, the crystal body (expansion unit) engages 10 on a disc-shaped damping element 22 made of a polymeric material. This in turn is supported by a spiral compression spring 24 from an underlying caseback 26 a lower housing portion 28 as abutment. In the in 1 the manner shown is the polymer body 22 to a radial diameter of the expansion unit 10 widens and becomes, by action of the compression spring 24 , against a through a lower face of the coil unit 12 formed ring heel 30 biased as a stop. Accordingly, by the between this annular shoulder 30 and the underlying abutment bottom section 26 a length limitation and thus a bias of serving as a biasing means element combination 22 . 24 causes; With this set biasing force, a force is applied to the ram unit 10 as soon as the elastomer body 22 not on the ring heel 30 is applied. Also, the component needs 22 Not necessarily be an elastomer or polymer body, it would also be a realization of aluminum or the like. Rigid materials possible.

In operation of the device according to 1 and in use, for example, for driving or gripping purposes at the front engagement end 18 Consequently, a force applied to a gripping object at this end, even if, after the expansion of the expansion unit 10 and terminated energization of the coil unit 12 , no further magnetic flux is left. This effect is also unlimited in that, in a variant (not shown), the stroke / length limitation by the annular shoulder 30 eliminated.

Advantageous effect is that about the advantageous gripping or driving insert of the actuator shown, the gripping object even then by the application of force (such as holding power) can be kept safe, even if the magnetic current is no longer present; In this respect, the prerequisite for a very energy-efficient robotics can thus be created, namely by energizing the arrangement only for the actual purposes of movement (and not for a subsequent holding).

Another advantage of in 1 shown device results from the fact that the bottom side, ie the expansion unit axially opposite, the (self-damping) polymer body 22 on a bottom ring heel 32 meets as an opposite stop; In that regard, there is an effective stroke limitation of the biasing or spring means unit 22 . 24 contrary to the direction of expansion, ie in the plane of the figure 1 down, in front.

The 2 structurally largely analogous to the first embodiment of the 1 and with correspondingly functionally identical functional components with corresponding reference numerals, clarifies the use of the actuator device according to the invention in connection with advantageously and further education associated return means in the form of a coil spring arranged as a compression spring 40 , This supports itself as the longitudinal section view of the 2 clarified, one inside of the upper housing section 20 from the other end of a shell side radially encircling the ram unit 16 projecting ring heel 42 , and thus biases the device against the direction of expansion. The spring force (by appropriate dimensioning of the spring constant) of the return spring 40 arranged such that the amount of this (restoring) spring force is greater than a Vorspannungs- or spring force amount of (in the direction of expansion, ie directed upward in the plane of the figure) biasing means 22 . 24 ,

Will now, in response to energization of the coil unit 12 , the expansion unit 10 expanded along its direction of expansion, can at the attack end 18 the ram unit 16 the desired interaction with an (external, not shown) adjusting partners done. After completion of the energization then leads (compressed by the expansion) return spring 40 over the ram unit 16 the expansion unit 10 back to your contracted starting position. Even if such a process is highly dynamic, ie consists of a very rapid expansion and an equally rapid contraction, it nevertheless advantageously does not lead to a potentially material-damaging bounce or rebound of the expansion unit 10 at the bottom abutment 26 because the intermediary biasing or spring means 22 . 24 provide for effective damping and cushioning of an impulse (down in the plane of the figure). Advantageously, a potentially negative effect of the undamped impact is therefore prevented in a material-friendly manner.

The present invention is not limited to the embodiments shown or the uses described; rather, the actuator device claimed according to the invention is suitable for a multiplicity of possible application and use environments, wherein improved dynamical properties cooperate synergistically in the ergindungsgemäß advantageous manner with permanently enabled application of force to a cooperating control partner.

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

• EP 1760796 B1 [0002]

Claims (10)

An actuator device comprising a magnetic shape memory alloy material (MSM) having an expansion movement along an expansion direction and configured to cooperate with an actuator and to perform an expansion movement in response to an induced magnetic flux (FIG. 10 ), which can be aligned along a longitudinal axis determined by the expansion direction on the adjusting partner and at one end an effective portion ( 14 . 18 ) for exerting a restoring force on the adjusting partner, characterized in that the expansion unit at the other end, in particular the operative portion opposite, biasing and / or spring means ( 22 . 24 ) are assigned so that in an unbiased by the magnetic flux operating state, the expansion unit can exert a force, in particular a pushing, setting and / or holding force on the control partner and / or can dampen the expansion unit. Apparatus according to claim 1, characterized in that the biasing or spring means of a stationary and / or stationary abutment portion ( 26 ), in particular abutment portion of a housing ( 28 ) of the actuator device, are formed supporting. Apparatus according to claim 1 or 2, characterized in that the biasing or spring means as compression spring ( 24 ) and / or as a body ( 22 ) are realized from an elastomeric material, in particular plastic material. Device according to one of claims 1 to 3, characterized in that the biasing or spring means connected in the direction of force, in particular stratified, plurality ( 22 . 24 ) are realized by resilient and / or elastic individual elements. Device according to one of claims 1 to 4, characterized in that the biasing means or spring means ( 32 ) are assigned to a stroke limitation of the expansion movement opposing spring and / or damping stroke. Apparatus according to claim 5, characterized in that the means for limiting the stroke a stationary and / or stationary first stop ( 32 ) and / or first paragraph for the biasing means or the expansion unit. Device according to one of claims 1 to 6, characterized in that the biasing or spring means own biasing means, in particular in the form of a mechanical Längenbegrenzung ( 30 . 32 ) are assigned along an extension direction, preferably as a second stop ( 30 ) and / or second paragraph are formed for the biasing or spring means. Use of the actuator device according to one of claims 1 to 7 for a gripping and / or driving device of a gripping object as an adjusting partner. System with the actuator device according to one of claims 1 to 7 and a restoring means for the expansion unit having adjusting partners, which are designed to exert a counter to the direction of expansion directed contraction force on the expansion unit, in particular in an unbiased by the magnetic flux operating state, wherein the return means are formed in that an amount of the contraction force is greater than the force exerted by the biasing means on the expansion unit. System according to claim 9, characterized in that the return means against the expansion direction biased or biased spring means whose spring force is greater than a spring force of the biasing or spring means.

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