CA2162318A1 - Drive apparatus with a drive element made from a shape memory alloy - Google Patents
Drive apparatus with a drive element made from a shape memory alloyInfo
- Publication number
- CA2162318A1 CA2162318A1 CA002162318A CA2162318A CA2162318A1 CA 2162318 A1 CA2162318 A1 CA 2162318A1 CA 002162318 A CA002162318 A CA 002162318A CA 2162318 A CA2162318 A CA 2162318A CA 2162318 A1 CA2162318 A1 CA 2162318A1
- Authority
- CA
- Canada
- Prior art keywords
- wire
- lever
- winding
- drive
- drive element
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F03—MACHINES OR ENGINES FOR LIQUIDS; WIND, SPRING, OR WEIGHT MOTORS; PRODUCING MECHANICAL POWER OR A REACTIVE PROPULSIVE THRUST, NOT OTHERWISE PROVIDED FOR
- F03G—SPRING, WEIGHT, INERTIA OR LIKE MOTORS; MECHANICAL-POWER PRODUCING DEVICES OR MECHANISMS, NOT OTHERWISE PROVIDED FOR OR USING ENERGY SOURCES NOT OTHERWISE PROVIDED FOR
- F03G7/00—Mechanical-power-producing mechanisms, not otherwise provided for or using energy sources not otherwise provided for
- F03G7/06—Mechanical-power-producing mechanisms, not otherwise provided for or using energy sources not otherwise provided for using expansion or contraction of bodies due to heating, cooling, moistening, drying or the like
- F03G7/061—Mechanical-power-producing mechanisms, not otherwise provided for or using energy sources not otherwise provided for using expansion or contraction of bodies due to heating, cooling, moistening, drying or the like characterised by the actuating element
- F03G7/0614—Mechanical-power-producing mechanisms, not otherwise provided for or using energy sources not otherwise provided for using expansion or contraction of bodies due to heating, cooling, moistening, drying or the like characterised by the actuating element using shape memory elements
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F03—MACHINES OR ENGINES FOR LIQUIDS; WIND, SPRING, OR WEIGHT MOTORS; PRODUCING MECHANICAL POWER OR A REACTIVE PROPULSIVE THRUST, NOT OTHERWISE PROVIDED FOR
- F03G—SPRING, WEIGHT, INERTIA OR LIKE MOTORS; MECHANICAL-POWER PRODUCING DEVICES OR MECHANISMS, NOT OTHERWISE PROVIDED FOR OR USING ENERGY SOURCES NOT OTHERWISE PROVIDED FOR
- F03G7/00—Mechanical-power-producing mechanisms, not otherwise provided for or using energy sources not otherwise provided for
- F03G7/06—Mechanical-power-producing mechanisms, not otherwise provided for or using energy sources not otherwise provided for using expansion or contraction of bodies due to heating, cooling, moistening, drying or the like
- F03G7/065—Mechanical-power-producing mechanisms, not otherwise provided for or using energy sources not otherwise provided for using expansion or contraction of bodies due to heating, cooling, moistening, drying or the like using a shape memory element
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H61/00—Electrothermal relays
- H01H61/01—Details
- H01H61/0107—Details making use of shape memory materials
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
- F05B—INDEXING SCHEME RELATING TO WIND, SPRING, WEIGHT, INERTIA OR LIKE MOTORS, TO MACHINES OR ENGINES FOR LIQUIDS COVERED BY SUBCLASSES F03B, F03D AND F03G
- F05B2280/00—Materials; Properties thereof
- F05B2280/50—Intrinsic material properties or characteristics
- F05B2280/5006—Shape memory
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T74/00—Machine element or mechanism
- Y10T74/18—Mechanical movements
- Y10T74/18024—Rotary to reciprocating and rotary
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T74/00—Machine element or mechanism
- Y10T74/18—Mechanical movements
- Y10T74/18024—Rotary to reciprocating and rotary
- Y10T74/18032—Rotary to reciprocating or rotary
Abstract
A drive apparatus for reversible movements of an actuator (9) is provided with a drive element made from a shape memory alloy with one-way effect. The drive element acts upon a lever (1) rotatable about an axle (2) in opposition to the force of a resetting element, wherein the lever (1) can be used as a coupling member for converting a deformation of the drive element into a movement of the actuator (9). The drive element is a winding (8) with a plurality of turns of a wire (7), wherein the turns are fixed and arranged mechanically parallel between an anchor point (6) and the lever (1) so that the lever (1) is rotatable about the axle (2) by means of a deformation of a turn, and the tractive force acting upon the lever (1) by means of the drive element results from the individual forces of the turns of the winding (8) acting mechanically parallel upon the lever (1). The diameter of the wire (7) is advantageously approximately equal to the standardised diameter of the crystalline grain of the shape memory alloy in the austenitic state.
Description
~16~318 _ DRIVE APPARATUS WITH A DRIVE ELEMENT MADE
FROM A SHAPE MEMORY ALLOY
The invention relates to a drive apparatus with a drive element made from a 5 shape memory alloy according to the preamble of claim 1.
Such drive apparatuses are suitable, for example, for actuating a valve plunger on a valve for controlling or regulating the flow of a liquid or gaseousflowable medium in heating, ventilation and air-conditioning technology.
It is known (P. Tautzenberger et al, Anwendung von Memory-Legierungen in elektrischen Schaltgeraten, Zeitschrift Metall, January 1985) to use shape memory alloys in electrical switchgear and thereby to make use of the one-way effect or the two-way effect of a shape memory alloy for switching an 15 electrical current.
A drive apparatus of the type described in the preamble of claim 1 is also known (DE-OS 37 31 146) in which a two-part element made from a shape memory alloy is configured so that the two component elements can each be 20 used, with the one-way effect, in opposition with respect to their direction of operation.
Making use of the shape memory effect of a shape memory alloy becomes critical when the effect has to produce a reproducible movement opposing a 25 relatively large force. The movement, for example, of actuating a valve has to be carried out in opposition to a force of approximately 100 N. The path of the movement achievable in this case is generally not reproducible over a large number of cycles.
30 The object of the invention is to configure a silent drive apparatus for reversible movements for operating an actuator so that the drive apparatus is ~16231~
, . .
able to apply the force necessary to operate the actuator and the movements are nevertheless reproducible over a large number of cycles.
The object described is solved according to the invention by the features of 5 claim 1. Advantageous configurations will be described in the dependent clalms.
In the following, embodiments of the invention will be described in more detail with reference to the drawings.
These show, in:
Fig. 1 the construction of a drive apparatus with a drive element made from a shape memory alloy, Fig. 2 the schematic diagram of the operation principles of the drive apparatus, Fig. 3 the diagram of development of a deformation of the drive element, Fig. 4 the grain structure of the shape memory alloy in the austenitic state, Fig. 5 the qualitative development of the electrical resistance of the drive element, Fig. 6 a schematic diagram of the electrical control of the drive element, Fig. 7 a diagram of the operation of the mechanical adjustment of the operating point, and Fig. 8 an electrical connection means for the drive element.
2162~18 w In Figure 1, the designation 1 refers to a lever rotatably mounted about an axle 2, which is provided at one end with a first bolt 3, advantageously arranged parallel to the axle 2, and at the other end with a bearing 4. The axle 2 is fixed to a housing 5, onto which a bolt 6 is arranged and fixed at a 5 set distance apart from the axle 2 and advantageously parallel to the axle 2.
A wire 7 is wound in a plurality of turns around the two parallel bolts 3 and 6 in such a way that the turns between the two bolts 3 and 6 are tensioned and thereby form a flat winding with a larger diameter 1, by means of which the two 10 bolts 3 and 6 are mechanically coupled with one another.
The lever 1 is coupled to an actuator by means of the bearing 4. The actuator is in this case a valve with a valve plunger 9 for controlling or regulating the flow of a liquid or gaseous flowable medium. The drive 15 apparatus shown can also be used for other actuators however, for example for ventilators.
The wire 7, and thereby also the winding 8 are composed of a shape memory alloy, whereby the winding 8 can be used as a silent drive element for moving 20 the lever 1 or for driving the actuator coupled to the lever 1 by means of the bearing 4.
The shape memory alloy and the wire 7 are advantageously selected and prepared so that the wire 7 shortens when it is heated to above a first 25 deformation initiation temperature As~ At temperatures above the first deformation termination temperature A" the shape memory alloy is in the austenitic state.
In Fig. 2 the advantageous drive apparatus according to Fig. 1 is shown again 30 schematically to clarify the principle of its operation. If the wire 7, and also thereby the larger diameter I of the flat winding 8 is shortened by heating of the wire 7, the lever 1 rotates counter-clockwise about the axle 2, as the axle 2 and also the winding 8 are fixed onto the housing 5. By heating the wire 7, the lever 1 can be rotated in opposition to a resetting force F away from a first stop 10 to a second stop 11, wherein the valve plunger 9 or an actuator is 5 operable by the bearing 4. The resetting force F is produced by a resetting element, wherein the reseKing element is preferabiy a spring.
When the wire 7 cools to below a second deformation initiation temperature Ms~ martensite is formed in the wire 7, whereby in the cooled state the yield 10 point in particular of the wire 7 is substantially reduced. At temperatures below the second deformation initiation temperature Ms the wire 7, and thereby the winding, can be extended by the resetting force F of the resetting element, so that the larger diameter I of the winding is enlarged. By means of the cooling of the wire 7 the lever 1 can be rotated by the resetting force 15 F away from the second stop 11 to the first stop 10, wherein the valve plunger 9 or actuator is operable by means of the bearing 4.
The two stops 10 and 11 respectively define a first limit of travel and a secondlimit of travel of the actuator. Advantageously the two stops 10 and 11 are 20 configured on the housing 5 and on the lever 1. The actuator is thus carried over to a first limit of travel by the heating of the wire 7 and to a second limit of travel by cooling of the wire 7.
Advantageously the resetting element is integrated into the actuator. In an 25 advantageous variation of the driving apparatus, the resetting element is formed by the plunger 9 pressed by a spring against the lever 1.
As the winding 8 is made up of a plurality of turns of the wire 7, the tractive force between the two bolts 3 and 6 occurring during heating above a first 30 deformation initiation temperature As is composed of a plurality of componentforces acting in a mechanically parallel manner, wherein one component force is composed of two individual forces of one turn occurring parallel to the larger diameter I of the flat winding 8. The tractive force is thereby proportional to the number of turns of the winding 8.
5 The deformation ~l of the winding 8 used as a drive element occurring during heating and cooling respectively is shown in Fig. 3. When the wire 7 is heated above the first deformation initiation temperature As to a first deformation termination temperature A~, a first deformation caused by the so-called memory effect occurs in the direction of a first arrow 12, while when the10 wire 7 is cooled below the second deformation initiation temperature Ms to a second deformation termination temperature M" a second deformation caused by the resetting element occurs in the direction of a second arrow 13. The first deformation of the drive elemént occurring upon heating is essentially a shortening, while the second deformation occurring upon cooling is an 1 5 extension.
As the winding 8 used as the drive element is advantageously provided with a plurality of turns acting mechanically parallel, a tractive force necessary for operating the actuator can also be attained with a relatively thin wire 7, in that 20 the number of turns in the winding is matched to the required tractive force.The tractive force of the winding 8, the resetting force of the resetting element and the transmission ratio of the lever 1 can be coordinated in a known manner with little expenditure. A necessary mechanical lifting of the actuator is to a large extent achievable because of the configuration of the rotatable 25 lever 1.
At temperatures above the first deformation initiation temperature As~ that is to say when the wire is in the heated state, the shape memory alloy has an austenitic microstructure, wherein the standardised diameter dK f a crystalline30 grain has a characteristic value. In a nickel-titanium alloy the standardiseddiameter dK of the grain is approximately 0.25 mm (S. Eucken: Progress in Shape Memory Alloys, DGM 1992, p. 178). If the diameter dD of the wire 7 -as shown in Fig. 4 - is approximately equal to the standardised diameter dK
of the grain of the shape memory alloy used for the drive element, the reversible movement of the drive element is also sufficiently accurately 5 reproducible over a large number of cycles - for example for 105 movement cycles. Using a nickel-titanium alloy, the diameter dD f the wire 7 is advantageously in the range of 0.1 mm to 0.4 mm. Furthermore, the capacity for reproduction of the reversible movement is improved in that the shortening occurring between the first deformation initiation temperature As and the first 10 deformation termination temperature A, is relatively small. With a nickel-titanium alloy advantageously a shortening of only approximately 3% is involved.
The electrical resistance R of the shape memory alloy has a hysteresis-type 15 development dependent upon the temperature T, as shown qualitatively in Fig.
5. With corresponding heating above the first deformation initiation temperature Asl the electrical resistance experiences a pronounced first change 14, while with corresponding cooling to below the second deformation initiation temperature Msl a pronounced second change 15 occurs.
The winding 8 used as the drive element is advantageously directly electrically heated, in that the winding 8 is switchably connected to a current or voltage source. Essentially, there are two variations by which the winding 8 can be supplied electrically. In a first variation, the wire 7 is connected to a source25 of electrical energy such that a switched-on current i flows through each turn of the winding 8, so that the individual turns are connected in series. In a second variation the individual turns of the winding 8 are connected in parallel, so that each turn also functions as the parallel connection between two sections of a turn each of which is the length of the larger diameter of the 30 winding 1.
~ 7 21fi2~18 In the first variation the individual turns of the winding 8 are wound so that they are electrically insulated from one another. Advantageously electrical insulation is produced in that the two bolts 3 and 6 used as winding supports are insulated with respect to the winding 8, and an insulating distance is 5 maintained between the individual turns. The two bolts 3 and 6 have, for example, insulation made from ceramics or a heat resistant plastics material.
The second variation has the advantage, with respect to the first variation, that the electrical insulation between the bolts 3 and 6 and the winding is 10 eliminated. In the second variation a current source is used for heating which advantageously is connected to the two bolts 3 and 6.
The deformation initiation temperatures As and Ms~ as well as the deformation termination temperatures A, and M, can be to a large extent matched to an 15 application by the appropriate choice of shape memory alloy.
If the shape memory alloy has a second deformation termination temperature M, which is substantially above the ambient temperature of the drive apparatus, cooling of the drive element can be obtained by switching off the 20 current in the wire 7. If with a nickel-titanium alloy the second deformationinitiation temperature is, for example, approximately 55C, and the second deformation termination temperature M, is approximately 35C, the cooling or extension of the drive element after switching off the current in the wire 7 lasts approximately 40 sec. at room temperature.
In Fig 6 an advantageous control apparatus for the winding 8 which can be used a drive element for a valve 17, is designated by 16. The control apparatus 16 connected to the winding 8 has an electrical energy source 19 controllable by means of a control input 18, and a measuring circuit 20. The 30 energy source 19 is advantageously a constant voltage or constant current source, the output value of which can at least be switched on and off by - ~162~18 means of the control input 18. In further variations of embodiments, the output value of the energy source 19 can be adjusted continuously or stepwise by means of the control input 18.
5 The two changes 14 and 15 (Fig. 5) in the electrical resistance R of the winding 8 can be sensed by the measuring circuit 20. As the electrical resistance 8 is measured when the control apparatus 16 is operating, a signal of the state of the form of the drive element, that is to say a signal of the state of opening or closure of the valve 17 is available in the measuring circuit 20.
10 The signal is available at an output 21 of the measuring circuit 20 as a feedback signal from the drive apparatus according to the invention.
Furthermore, where required an instantaneous value of the signal can be stored in the control apparatus 16.
15 A feedback signal from the drive apparatus is available by means of the advantageous control apparatus 16 without additional expenditure in the form of a wiring system or an assembly being necessary for obtaining the signal at the valve 17 or at the drive element, that is to say the winding 8.
20 In the schematic representation of the winding 8 tensioned between the two bolts 3 and 6, and of the lever 1 rotatable about the axle 2 and acting upon the valve plunger 9 shown in Fig. 7, a screw is designated 30 and a bracket fixed to the second bolt 6 is designated 31, which has a thread 32 matching the screw 30. The screw 30 and the bracket 31 are mounted and guided by 25 a guiding means 33 advantageously configured on the housing 5, such that the second bolt 6 is moveable in a linear manner in a specific area by rotation of the screw 30, whereby the winding 8 can be extended.
The screw 30, the bracket 31 and the guiding means 33 form an 30 advantageous adjustment means for adjusting the operating point of the drive element, that is to say the winding 8, upon the valve plunger 9, wherein the 9 216231~
operating point can be adjusted by rotation of the screw 30. Essentially the operating point of the drive element is adjusted by means of the adjustment means by extension or relaxation of the winding 8. Naturally, the representation of the adjustment means in Fig. 7 is just one variation among 5 a large number of possible variations of the adjustment means; a further variation of the adjustment means could act directly on the lever 1, whereby the extension or relaxation of the winding 8 required for adjustment of the operating point would take place via the lever 1.
10 In Fig. 8 a mechanical compensating element is designated 36, by means of which the wire 7 is guided from the winding 8 to a terminal 37 to which the control apparatus 16 or another electrical voltage or current source can be connected. The compensating element 36 is configured and arranged so that a mechanical tensile stress cJ occurring in the wire 7 between the second bolt 15 6 and the terminal 37 when the wire 7 is directly heated is limited. The compensating element 36 is provided, for example, with an elastic tongue 36a which can be displaced in the direction of a further arrow 38 when there is an increasingly large tensile stress ~ sufficiently far so that the tensile stress a is always limited to a permissible value during direct heating, so that the wire20 7 is not mechanically overloaded.
Advantageously, the mechanical compensating element 36 is made from a polymer which is elastic, electrically insulating and temperature resistant, andin addition is a poor dissipator of heat. The compensating element 36 and the 25 terminal 37 form an advantageous electrical connection means for the winding 8, in which a tensile stress ~J occurring between the terminal 37 and the anchor point 6 of the winding 8 when there is direct heating is limited to a permissible value by an elastic deformation of the compensating element 36.
30 A winding body 40, advantageously provided with at least one bar 39, is used for producing the winding 8, which can be displaced over the two bolts 3 and 6 in order to mount the winding 8 in the housing 5, wherein after the winding 8 has been mounted in the housing 5, and before the initiation of the drive apparatus, the bar 39 is removed so that the two bolts 3 and 6 are moveable with respect to one another by means of the winding 8. Advantageously the 5 bar 39 is provided with breaking points 41, by means of which the bar 39 can be removed by being broken off.
FROM A SHAPE MEMORY ALLOY
The invention relates to a drive apparatus with a drive element made from a 5 shape memory alloy according to the preamble of claim 1.
Such drive apparatuses are suitable, for example, for actuating a valve plunger on a valve for controlling or regulating the flow of a liquid or gaseousflowable medium in heating, ventilation and air-conditioning technology.
It is known (P. Tautzenberger et al, Anwendung von Memory-Legierungen in elektrischen Schaltgeraten, Zeitschrift Metall, January 1985) to use shape memory alloys in electrical switchgear and thereby to make use of the one-way effect or the two-way effect of a shape memory alloy for switching an 15 electrical current.
A drive apparatus of the type described in the preamble of claim 1 is also known (DE-OS 37 31 146) in which a two-part element made from a shape memory alloy is configured so that the two component elements can each be 20 used, with the one-way effect, in opposition with respect to their direction of operation.
Making use of the shape memory effect of a shape memory alloy becomes critical when the effect has to produce a reproducible movement opposing a 25 relatively large force. The movement, for example, of actuating a valve has to be carried out in opposition to a force of approximately 100 N. The path of the movement achievable in this case is generally not reproducible over a large number of cycles.
30 The object of the invention is to configure a silent drive apparatus for reversible movements for operating an actuator so that the drive apparatus is ~16231~
, . .
able to apply the force necessary to operate the actuator and the movements are nevertheless reproducible over a large number of cycles.
The object described is solved according to the invention by the features of 5 claim 1. Advantageous configurations will be described in the dependent clalms.
In the following, embodiments of the invention will be described in more detail with reference to the drawings.
These show, in:
Fig. 1 the construction of a drive apparatus with a drive element made from a shape memory alloy, Fig. 2 the schematic diagram of the operation principles of the drive apparatus, Fig. 3 the diagram of development of a deformation of the drive element, Fig. 4 the grain structure of the shape memory alloy in the austenitic state, Fig. 5 the qualitative development of the electrical resistance of the drive element, Fig. 6 a schematic diagram of the electrical control of the drive element, Fig. 7 a diagram of the operation of the mechanical adjustment of the operating point, and Fig. 8 an electrical connection means for the drive element.
2162~18 w In Figure 1, the designation 1 refers to a lever rotatably mounted about an axle 2, which is provided at one end with a first bolt 3, advantageously arranged parallel to the axle 2, and at the other end with a bearing 4. The axle 2 is fixed to a housing 5, onto which a bolt 6 is arranged and fixed at a 5 set distance apart from the axle 2 and advantageously parallel to the axle 2.
A wire 7 is wound in a plurality of turns around the two parallel bolts 3 and 6 in such a way that the turns between the two bolts 3 and 6 are tensioned and thereby form a flat winding with a larger diameter 1, by means of which the two 10 bolts 3 and 6 are mechanically coupled with one another.
The lever 1 is coupled to an actuator by means of the bearing 4. The actuator is in this case a valve with a valve plunger 9 for controlling or regulating the flow of a liquid or gaseous flowable medium. The drive 15 apparatus shown can also be used for other actuators however, for example for ventilators.
The wire 7, and thereby also the winding 8 are composed of a shape memory alloy, whereby the winding 8 can be used as a silent drive element for moving 20 the lever 1 or for driving the actuator coupled to the lever 1 by means of the bearing 4.
The shape memory alloy and the wire 7 are advantageously selected and prepared so that the wire 7 shortens when it is heated to above a first 25 deformation initiation temperature As~ At temperatures above the first deformation termination temperature A" the shape memory alloy is in the austenitic state.
In Fig. 2 the advantageous drive apparatus according to Fig. 1 is shown again 30 schematically to clarify the principle of its operation. If the wire 7, and also thereby the larger diameter I of the flat winding 8 is shortened by heating of the wire 7, the lever 1 rotates counter-clockwise about the axle 2, as the axle 2 and also the winding 8 are fixed onto the housing 5. By heating the wire 7, the lever 1 can be rotated in opposition to a resetting force F away from a first stop 10 to a second stop 11, wherein the valve plunger 9 or an actuator is 5 operable by the bearing 4. The resetting force F is produced by a resetting element, wherein the reseKing element is preferabiy a spring.
When the wire 7 cools to below a second deformation initiation temperature Ms~ martensite is formed in the wire 7, whereby in the cooled state the yield 10 point in particular of the wire 7 is substantially reduced. At temperatures below the second deformation initiation temperature Ms the wire 7, and thereby the winding, can be extended by the resetting force F of the resetting element, so that the larger diameter I of the winding is enlarged. By means of the cooling of the wire 7 the lever 1 can be rotated by the resetting force 15 F away from the second stop 11 to the first stop 10, wherein the valve plunger 9 or actuator is operable by means of the bearing 4.
The two stops 10 and 11 respectively define a first limit of travel and a secondlimit of travel of the actuator. Advantageously the two stops 10 and 11 are 20 configured on the housing 5 and on the lever 1. The actuator is thus carried over to a first limit of travel by the heating of the wire 7 and to a second limit of travel by cooling of the wire 7.
Advantageously the resetting element is integrated into the actuator. In an 25 advantageous variation of the driving apparatus, the resetting element is formed by the plunger 9 pressed by a spring against the lever 1.
As the winding 8 is made up of a plurality of turns of the wire 7, the tractive force between the two bolts 3 and 6 occurring during heating above a first 30 deformation initiation temperature As is composed of a plurality of componentforces acting in a mechanically parallel manner, wherein one component force is composed of two individual forces of one turn occurring parallel to the larger diameter I of the flat winding 8. The tractive force is thereby proportional to the number of turns of the winding 8.
5 The deformation ~l of the winding 8 used as a drive element occurring during heating and cooling respectively is shown in Fig. 3. When the wire 7 is heated above the first deformation initiation temperature As to a first deformation termination temperature A~, a first deformation caused by the so-called memory effect occurs in the direction of a first arrow 12, while when the10 wire 7 is cooled below the second deformation initiation temperature Ms to a second deformation termination temperature M" a second deformation caused by the resetting element occurs in the direction of a second arrow 13. The first deformation of the drive elemént occurring upon heating is essentially a shortening, while the second deformation occurring upon cooling is an 1 5 extension.
As the winding 8 used as the drive element is advantageously provided with a plurality of turns acting mechanically parallel, a tractive force necessary for operating the actuator can also be attained with a relatively thin wire 7, in that 20 the number of turns in the winding is matched to the required tractive force.The tractive force of the winding 8, the resetting force of the resetting element and the transmission ratio of the lever 1 can be coordinated in a known manner with little expenditure. A necessary mechanical lifting of the actuator is to a large extent achievable because of the configuration of the rotatable 25 lever 1.
At temperatures above the first deformation initiation temperature As~ that is to say when the wire is in the heated state, the shape memory alloy has an austenitic microstructure, wherein the standardised diameter dK f a crystalline30 grain has a characteristic value. In a nickel-titanium alloy the standardiseddiameter dK of the grain is approximately 0.25 mm (S. Eucken: Progress in Shape Memory Alloys, DGM 1992, p. 178). If the diameter dD of the wire 7 -as shown in Fig. 4 - is approximately equal to the standardised diameter dK
of the grain of the shape memory alloy used for the drive element, the reversible movement of the drive element is also sufficiently accurately 5 reproducible over a large number of cycles - for example for 105 movement cycles. Using a nickel-titanium alloy, the diameter dD f the wire 7 is advantageously in the range of 0.1 mm to 0.4 mm. Furthermore, the capacity for reproduction of the reversible movement is improved in that the shortening occurring between the first deformation initiation temperature As and the first 10 deformation termination temperature A, is relatively small. With a nickel-titanium alloy advantageously a shortening of only approximately 3% is involved.
The electrical resistance R of the shape memory alloy has a hysteresis-type 15 development dependent upon the temperature T, as shown qualitatively in Fig.
5. With corresponding heating above the first deformation initiation temperature Asl the electrical resistance experiences a pronounced first change 14, while with corresponding cooling to below the second deformation initiation temperature Msl a pronounced second change 15 occurs.
The winding 8 used as the drive element is advantageously directly electrically heated, in that the winding 8 is switchably connected to a current or voltage source. Essentially, there are two variations by which the winding 8 can be supplied electrically. In a first variation, the wire 7 is connected to a source25 of electrical energy such that a switched-on current i flows through each turn of the winding 8, so that the individual turns are connected in series. In a second variation the individual turns of the winding 8 are connected in parallel, so that each turn also functions as the parallel connection between two sections of a turn each of which is the length of the larger diameter of the 30 winding 1.
~ 7 21fi2~18 In the first variation the individual turns of the winding 8 are wound so that they are electrically insulated from one another. Advantageously electrical insulation is produced in that the two bolts 3 and 6 used as winding supports are insulated with respect to the winding 8, and an insulating distance is 5 maintained between the individual turns. The two bolts 3 and 6 have, for example, insulation made from ceramics or a heat resistant plastics material.
The second variation has the advantage, with respect to the first variation, that the electrical insulation between the bolts 3 and 6 and the winding is 10 eliminated. In the second variation a current source is used for heating which advantageously is connected to the two bolts 3 and 6.
The deformation initiation temperatures As and Ms~ as well as the deformation termination temperatures A, and M, can be to a large extent matched to an 15 application by the appropriate choice of shape memory alloy.
If the shape memory alloy has a second deformation termination temperature M, which is substantially above the ambient temperature of the drive apparatus, cooling of the drive element can be obtained by switching off the 20 current in the wire 7. If with a nickel-titanium alloy the second deformationinitiation temperature is, for example, approximately 55C, and the second deformation termination temperature M, is approximately 35C, the cooling or extension of the drive element after switching off the current in the wire 7 lasts approximately 40 sec. at room temperature.
In Fig 6 an advantageous control apparatus for the winding 8 which can be used a drive element for a valve 17, is designated by 16. The control apparatus 16 connected to the winding 8 has an electrical energy source 19 controllable by means of a control input 18, and a measuring circuit 20. The 30 energy source 19 is advantageously a constant voltage or constant current source, the output value of which can at least be switched on and off by - ~162~18 means of the control input 18. In further variations of embodiments, the output value of the energy source 19 can be adjusted continuously or stepwise by means of the control input 18.
5 The two changes 14 and 15 (Fig. 5) in the electrical resistance R of the winding 8 can be sensed by the measuring circuit 20. As the electrical resistance 8 is measured when the control apparatus 16 is operating, a signal of the state of the form of the drive element, that is to say a signal of the state of opening or closure of the valve 17 is available in the measuring circuit 20.
10 The signal is available at an output 21 of the measuring circuit 20 as a feedback signal from the drive apparatus according to the invention.
Furthermore, where required an instantaneous value of the signal can be stored in the control apparatus 16.
15 A feedback signal from the drive apparatus is available by means of the advantageous control apparatus 16 without additional expenditure in the form of a wiring system or an assembly being necessary for obtaining the signal at the valve 17 or at the drive element, that is to say the winding 8.
20 In the schematic representation of the winding 8 tensioned between the two bolts 3 and 6, and of the lever 1 rotatable about the axle 2 and acting upon the valve plunger 9 shown in Fig. 7, a screw is designated 30 and a bracket fixed to the second bolt 6 is designated 31, which has a thread 32 matching the screw 30. The screw 30 and the bracket 31 are mounted and guided by 25 a guiding means 33 advantageously configured on the housing 5, such that the second bolt 6 is moveable in a linear manner in a specific area by rotation of the screw 30, whereby the winding 8 can be extended.
The screw 30, the bracket 31 and the guiding means 33 form an 30 advantageous adjustment means for adjusting the operating point of the drive element, that is to say the winding 8, upon the valve plunger 9, wherein the 9 216231~
operating point can be adjusted by rotation of the screw 30. Essentially the operating point of the drive element is adjusted by means of the adjustment means by extension or relaxation of the winding 8. Naturally, the representation of the adjustment means in Fig. 7 is just one variation among 5 a large number of possible variations of the adjustment means; a further variation of the adjustment means could act directly on the lever 1, whereby the extension or relaxation of the winding 8 required for adjustment of the operating point would take place via the lever 1.
10 In Fig. 8 a mechanical compensating element is designated 36, by means of which the wire 7 is guided from the winding 8 to a terminal 37 to which the control apparatus 16 or another electrical voltage or current source can be connected. The compensating element 36 is configured and arranged so that a mechanical tensile stress cJ occurring in the wire 7 between the second bolt 15 6 and the terminal 37 when the wire 7 is directly heated is limited. The compensating element 36 is provided, for example, with an elastic tongue 36a which can be displaced in the direction of a further arrow 38 when there is an increasingly large tensile stress ~ sufficiently far so that the tensile stress a is always limited to a permissible value during direct heating, so that the wire20 7 is not mechanically overloaded.
Advantageously, the mechanical compensating element 36 is made from a polymer which is elastic, electrically insulating and temperature resistant, andin addition is a poor dissipator of heat. The compensating element 36 and the 25 terminal 37 form an advantageous electrical connection means for the winding 8, in which a tensile stress ~J occurring between the terminal 37 and the anchor point 6 of the winding 8 when there is direct heating is limited to a permissible value by an elastic deformation of the compensating element 36.
30 A winding body 40, advantageously provided with at least one bar 39, is used for producing the winding 8, which can be displaced over the two bolts 3 and 6 in order to mount the winding 8 in the housing 5, wherein after the winding 8 has been mounted in the housing 5, and before the initiation of the drive apparatus, the bar 39 is removed so that the two bolts 3 and 6 are moveable with respect to one another by means of the winding 8. Advantageously the 5 bar 39 is provided with breaking points 41, by means of which the bar 39 can be removed by being broken off.
Claims (9)
1. Drive apparatus with a drive element made from a shape memory alloy with one-way effect, for reversible movements of an actuator (9), characterised in that the drive element acts upon a lever (1) rotatable about an axle (2), in opposition to the force of a resetting element, wherein the lever (1 ) can be used as a coupling member for converting a deformation of the drive element into a movement of the actuator (9), the drive element is a winding (8) with a plurality of turns of a wire (7), wherein the turns are fixed and arranged mechanically parallel between an anchor point (6) and the lever (1 ) so that the lever (1 ) is rotatable about the axle (2) by means of a deformation of a turn, and the tractive force acting upon the lever (1) by means of the drive element results from the individual forces of the turns of the winding (8) acting mechanically parallel upon the lever (1).
2. Drive apparatus according to claim 1, characterised in that the drive element (8) and the resetting element are configured so that the wire (7) shortens substantially when heated above a pre-determined temperature (As), so that the movement of the drive element (8) places the actuator (9) in a first end position and the wire (7) extends substantially when cooled below a further pre-determined temperature (As) by means of the force of the resetting element, so that the movement of the drive element (8) brings the actuator (9) into a second end position.
3. Drive apparatus according to one of the preceding claims, characterised in that the diameter (dD) of the wire (7) made from the shape memory alloy is equal to the standardised diameter (dK) of the crystalline grain of the shape memory alloy in the austenitic state.
4. Drive apparatus according to one of the preceding claims, characterised in that the diameter of the wire made from the shape memory alloy is less that 0.4 mm.
5. Drive apparatus according to one of the preceding claims, characterised in that the shape memory alloy is a nickel-titanium alloy.
6. Drive apparatus according to one of the preceding claims, characterised by an electrical energy source (19) connectable to the wire, by means of which the wire (7) can be directly electrically heated.
7. Drive apparatus according to claim 6, characterised by an electronic measuring circuit (20) by means of which a change in the electrical resistance (R) of the wire (7) can be sensed, wherein by means of the measuring circuit (20) an electrical signal with the current state of the form of the drive element (8), or of the current state of the actuator (9) can be produced at an output (21).
8. Drive apparatus according to one of the preceding claims, characterised by an adjustment means (30, 31, 33), by means of which the winding (8) tensioned between the two bolts (3, 6) can be further tensioned or relaxed in order to adjust the mechanical operating point.
9. Drive apparatus according to one of the preceding claims, characterised in that an electrical connection means for the winding (8) is provided with a terminal (37) and a mechanically elastic compensating element (36), wherein the two ends of the wire (7) can be connected to the terminal and wherein the compensating element (36) is configured and arranged so that a tensile stress (.sigma.) between the terminal (37) and the anchor point (6) of the winding (8) occurring in the wire (7) connected to the terminal (37) when it is directly heated is limited to a permissible value by an elastic deformation of the compensating element (36).
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CH3395/94-0 | 1994-11-14 | ||
| CH339594 | 1994-11-14 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2162318A1 true CA2162318A1 (en) | 1996-05-15 |
Family
ID=4255055
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002162318A Abandoned CA2162318A1 (en) | 1994-11-14 | 1995-11-07 | Drive apparatus with a drive element made from a shape memory alloy |
Country Status (11)
| Country | Link |
|---|---|
| US (1) | US5685148A (en) |
| EP (1) | EP0712145B1 (en) |
| JP (1) | JPH08226376A (en) |
| KR (1) | KR960018229A (en) |
| AT (1) | ATE175517T1 (en) |
| CA (1) | CA2162318A1 (en) |
| DE (1) | DE59504728D1 (en) |
| DK (1) | DK0712145T3 (en) |
| ES (1) | ES2127448T3 (en) |
| FI (1) | FI105354B (en) |
| NO (1) | NO954599L (en) |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5949522A (en) * | 1996-07-03 | 1999-09-07 | Manne; Joseph S. | Multimedia linked scent delivery system |
| DE59707167D1 (en) | 1997-11-27 | 2002-06-06 | Siemens Building Tech Ag | Drive device for reversibly driving a valve |
| WO1999060235A2 (en) * | 1998-05-18 | 1999-11-25 | Slc Technologies, Inc. | Electrically controlled lock employing shape memory alloy |
| DE60031687T2 (en) * | 1999-08-12 | 2007-09-06 | Perihelian, LLC, Berkley | DRIVE FROM A FORM MEMORY ALLOY AND METHOD FOR CONTROLLING |
| US6247678B1 (en) * | 1999-11-01 | 2001-06-19 | Swagelok Company | Shape memory alloy actuated fluid control valve |
| US6326707B1 (en) * | 2000-05-08 | 2001-12-04 | Mark A. Gummin | Shape memory alloy actuator |
| US6832477B2 (en) * | 2000-05-08 | 2004-12-21 | Mark A Gummin | Shape memory alloy actuator |
| DE60226160T2 (en) | 2001-02-22 | 2009-07-02 | Alfmeier Präzision AG Baugruppen und Systemlösungen | MEMBRANE OF MEMORY METAL WITH IMPROVED TEMPERATURE CONTROL |
| ATE449227T1 (en) * | 2002-02-27 | 2009-12-15 | Emz Hanauer Gmbh & Co Kgaa | UNIT WITH MEMORY METAL ACTUATOR FOR DOOR LOCKS OF HOUSEHOLD APPLIANCES |
| DE10214398A1 (en) * | 2002-03-30 | 2003-10-16 | Kiekert Ag | locking device |
| US8127543B2 (en) | 2002-05-06 | 2012-03-06 | Alfmeier Prazision Ag Baugruppen Und Systemlosungen | Methods of manufacturing highly integrated SMA actuators |
| WO2003093615A1 (en) | 2002-05-06 | 2003-11-13 | Nanomuscle, Inc. | Reusable shape memory alloy activated latch |
| EP1540138B1 (en) * | 2002-05-06 | 2015-09-16 | Alfmeier Präzision AG Baugruppen und Systemlösungen | Actuator for two angular degrees of freedom |
| KR20040106495A (en) * | 2002-05-06 | 2004-12-17 | 나노머슬, 인크. | High stroke, highly integrated sma actuators |
| WO2004075263A2 (en) * | 2003-02-19 | 2004-09-02 | The Trustees Of Columbia University In The City Of New York | System and process for processing a plurality of semiconductor thin films which are crystallized using sequential lateral solidification techniques |
| US7093817B2 (en) | 2003-04-28 | 2006-08-22 | Alfmeier Prazision Ag Baugruppen Und Systemlosungen | Flow control assemblies having integrally formed shape memory alloy actuators |
| EP1620837A2 (en) * | 2003-05-02 | 2006-02-01 | Alfmeier Präzision Ag Baugruppen und Systemlösungen | Gauge pointer with integrated shape memory alloy actuator |
| US7451595B2 (en) * | 2003-05-12 | 2008-11-18 | Mitsubishi Electric Corporation | Drive device |
| EP1664604B3 (en) | 2003-09-05 | 2020-09-23 | Alfmeier Präzision SE | A system, method and apparatus for reducing frictional forces and for compensating shape memory alloy-actuated valves and valve systems at high temperatures |
| KR100724798B1 (en) * | 2005-01-11 | 2007-06-04 | 이종소 | Automatic valve actuating apparatus using shape memory alloy and assembling method thereof |
| US7650914B2 (en) * | 2006-06-22 | 2010-01-26 | Autosplice, Inc. | Apparatus and methods for filament crimping and manufacturing |
| US7953319B2 (en) * | 2007-04-04 | 2011-05-31 | Konica Minolta Opto, Inc. | Position controller, driving mechanism and image pickup system |
| US8230682B1 (en) | 2009-09-24 | 2012-07-31 | The United States Of America As Represented By The Secretary Of The Navy | Thermally activated initiator assembly |
| WO2011058103A2 (en) * | 2009-11-12 | 2011-05-19 | Laerdal Medical As | Pulse simulation unit |
| WO2012023605A1 (en) * | 2010-08-20 | 2012-02-23 | 株式会社青電舎 | Shock-driven actuator |
| FR2968372B1 (en) * | 2010-12-06 | 2012-12-21 | Centre Nat Etd Spatiales | BRAKE BEAM HAMMER DEVICE IN SHAPE MEMORY MATERIAL. |
| US8851443B2 (en) | 2010-12-15 | 2014-10-07 | Autosplice, Inc. | Memory alloy-actuated apparatus and methods for making and using the same |
| WO2013063511A2 (en) * | 2011-10-26 | 2013-05-02 | Autosplice, Inc. | Memory alloy-actuated appratus and methods for making and using the same |
| GB2555655A (en) * | 2016-11-08 | 2018-05-09 | Eaton Ind Ip Gmbh & Co Kg | Valve assembly and method for controlling a flow of a fluid using a shape memory alloy member |
| US11739737B2 (en) | 2018-02-07 | 2023-08-29 | Autosplice, Inc. | Shape memory alloy filament crimping element |
| CN113203224B (en) * | 2020-02-03 | 2023-03-28 | 香港科技大学 | Heat regenerator and refrigerating system comprising same |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3174851A (en) * | 1961-12-01 | 1965-03-23 | William J Buehler | Nickel-base alloys |
| US3613732A (en) * | 1969-07-17 | 1971-10-19 | Robertshaw Controls Co | Temperature-responsive valve operators |
| US3680306A (en) * | 1969-11-10 | 1972-08-01 | Vysshee Tekhn Uchilische Im N | Reciprocating drives for the movable members of shut-off elements |
| US3893055A (en) * | 1973-04-16 | 1975-07-01 | Texas Instruments Inc | High gain relays and systems |
| US3858141A (en) * | 1973-12-03 | 1974-12-31 | Texas Instruments Inc | Reduced actuation time thermal relay system |
| US4086769A (en) * | 1975-05-19 | 1978-05-02 | The United States Of America As Represented By The Secretary Of The Navy | Compound memory engine |
| US4450686A (en) * | 1983-03-21 | 1984-05-29 | Banks Ridgway M | Single wire nitinol engine |
| JPS60175777A (en) * | 1984-02-21 | 1985-09-09 | Shigeo Hirose | Shape-memory actuator |
| DE3731146A1 (en) * | 1987-09-16 | 1989-03-30 | Siemens Ag | Drive device made of shape-memory alloy |
| US4811564A (en) * | 1988-01-11 | 1989-03-14 | Palmer Mark D | Double action spring actuator |
| DE4209815A1 (en) * | 1992-03-26 | 1993-09-30 | Braun Ag | Temp. sensitive actuator for electric razor - contains drive part of memory shape material, restoring spring, transfer connector and mechanical control element |
-
1995
- 1995-10-04 AT AT95115615T patent/ATE175517T1/en not_active IP Right Cessation
- 1995-10-04 EP EP95115615A patent/EP0712145B1/en not_active Expired - Lifetime
- 1995-10-04 ES ES95115615T patent/ES2127448T3/en not_active Expired - Lifetime
- 1995-10-04 DE DE59504728T patent/DE59504728D1/en not_active Expired - Fee Related
- 1995-10-04 DK DK95115615T patent/DK0712145T3/en active
- 1995-10-19 US US08/545,268 patent/US5685148A/en not_active Expired - Fee Related
- 1995-10-30 KR KR1019950038243A patent/KR960018229A/en not_active Application Discontinuation
- 1995-11-07 CA CA002162318A patent/CA2162318A1/en not_active Abandoned
- 1995-11-07 JP JP7288212A patent/JPH08226376A/en active Pending
- 1995-11-13 FI FI955461A patent/FI105354B/en active
- 1995-11-14 NO NO954599A patent/NO954599L/en not_active Application Discontinuation
Also Published As
| Publication number | Publication date |
|---|---|
| FI955461A (en) | 1996-05-15 |
| ATE175517T1 (en) | 1999-01-15 |
| JPH08226376A (en) | 1996-09-03 |
| NO954599D0 (en) | 1995-11-14 |
| EP0712145A1 (en) | 1996-05-15 |
| DK0712145T3 (en) | 1999-08-30 |
| NO954599L (en) | 1996-05-15 |
| KR960018229A (en) | 1996-06-17 |
| DE59504728D1 (en) | 1999-02-18 |
| FI105354B (en) | 2000-07-31 |
| US5685148A (en) | 1997-11-11 |
| ES2127448T3 (en) | 1999-04-16 |
| EP0712145B1 (en) | 1999-01-07 |
| FI955461A0 (en) | 1995-11-13 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Discontinued |