FR2527372A1 - ELEMENT HAVING A MEMORY OF SHAPE AND OF WHICH THE DEFORMATIONS ARE OBTAINED BY VARIATION OF THE TEMPERATURE - Google Patents

Abstract

THIS ELEMENT MAY BE IN THE FORM OF A PLATE 1 OR SIMILAR WITH AT LEAST ONE SLOT 3 DELIMING A PART 4 DEFORMABLE AS A FUNCTION OF THE TEMPERATURE UNDER THE INFLUENCE OF THE FORM MEMORY EFFECT. THE ELEMENT CAN BE USED AS A FLOW CONTROL DEVICE, AS A FIXING DEVICE, OR AS A MOVABLE MECHANICAL PARTS ACTUATOR.

Description

The present invention relates to shape memory organs.

  components can be used for example as thermal control devices, rings

  tightening, and in many other areas.

  The shape memory effect is specific to various materials and essentially consists of an element

  made of this material and having a certain original form

  tiale, deforms plastically to take another

  form at an appropriate temperature, will automatically

  that, at least to some extent, its original form

  tial at a different temperature or will tend to do so according to the degree of external stress to which it is subjected Thus, such elements, in their new

  form, may be subjected to heating or cooling

  cooling through a characteristic temperature range of transformation of the material, so as to cause deformation to their initial shape or to

  tend to cause this deformation and thus exercise

  simply put a force on another element Trans-

  training can be made automatically reversible by

  function of temperature changes.

  The shape memory effect is presented in parti-

  especially by certain alloys whose composition has a predominance in phase e which undergoes a transformation from austenite at a relatively high temperature into martensite at a relatively low temperature, and the reverse transformation at a higher temperature These alloys include the alloys Ni-Ti, In-Tl, Au-Cd, AgZn, and (Ni 1 X Cux) -Ti Particularly preferable alloys are Cu alloys with ur or several metals such as, for example, Zn, Al, Ni , Mn, Sn or Co. In general, the shape memory effect has been used in the field of flow control.

  fluids in actuators for obturators

  rators or the like Although such arrangements do

  feel many benefits like good sensitivity

  and a quick response, there remains the fact that the body

  memory with form memory replaces an action organ-

  known in an otherwise relatively device

  classic We proposed a carburetor nozzle in al-

  shape memory liaae, the cross section of which varies with temperature However, the changes involved do not

  would not be of great amplitude, and in a particular case

  : ier proposed, the reduction of the nozzle orifice over a temperature range of approximately 50 L is approximately 0.008 mm.

  One of the aims of the invention is therefore to provide

  provide an improved flow control device,

  using the shape memory effect.

  The shape memory effect has also been proposed

  in the field of retaining or fixing members.

  Thus, shape memory alloy clamping rings have been proposed, as well as C-shaped staples. Another object of this invention is therefore to provide means which allow retaining or retaining arrangements.

more flexible attachment.

  Another object of the invention is to provide

  means that allow the construction of perfect types-

  born from actuators intended for use in

very varied fields.

  Thus, in one aspect, the invention

  provides an element in shape memory material

  both at least one slit delimiting, at least in part, a part of the element intended to deform or to have a tendency to s-e deform under the effect of a change of

  temperature, due to a shape memory effect.

  In the field of fluid flow, the arrangement will generally be such that the element is placed in the flow path, the deformable part

  deforming to control flow through the element

  ment Thus, it is the deformable part itself which directly controls the flow, given that it is in the path thereof. This design is

  different from the known arrangements in which the element

  memory form only serves as an actuating organ.

  In the arrangement described above, the opening

  ture through which the flow takes place is the element itself Therefore, the flow section of the slot delimiting the element will actually increase or decrease with the deformations of the element Good

  of course, in the "open" position, the slot can be changed

  even in a different type of opening Although the deformable part can cooperate with another element to regulate the flow, the above arrangement is that

  which is preferred and thus, in another aspect, the invention

  tion provides compression flow control means

  nant an element intended to be placed in the flow path, this element having an opening in which extends part of the element, this part being in shape memory material and deformable with a change in temperature, under influence of the effect

  of shape memory, so as to modify the section of

opening flow.

  In general, the deformation will wear the part

  deformable in the plane or out of the plane of the opening.

  A flow control using an element in accordance with the invention could relate to liquids, gases or solids. The element could for example serve as a shutter of an air fan, or as

  screening means for solid particulate material.

  In the context of retaining or fixing members, the deformable part will for example have the form

  a tab intended to cooperate with another element.

  It can deform to come into contact with the jatrt

  element, thereby exerting a clamping force or

  rusting on part of the other element, for example.

  In certain circumstances, no movement is born.

  stop and in this case it is the tendency to deform which causes the clamping force. Seen in another aspect, the invention provides an element having means for securing the element to another element, these means comprising a part of the element in the form of a lug of memory material intended to be deform or have a tendency to deform with respect to adjacent parts of the element under the action of a temperature change, under the influence of the shape memory effect, to

cooperate with the other element.

  In the context of actuating members, the invention makes it possible to use as basic elements, for example, coil springs made of memory alloy

  form So, for example, an actuator for-

  could replace a conventional diaphragm spring fitted with el-

  radially directed elements, which are delimited, for example,

  by slots, and which deform.

  * Thus, seen from another aspect, the invention

  provides an actuator in the form of a plate

  that comprising several elements extending radially and in a shape memory material arranged and adapted

  so that after a change in temperature

  ture, the plate undergoes or tends to undergo a modification

  tion of shape under the influence of a shape memory effect.

  It will be understood that, in the field of fixing

  tion, or actuators, the main function

  tion of the slot or other opening will generally allow the formation of a tab tab or the like from the material of the base member, while in flow control, the opening normally the function, generally besides defining the tongue, of providing a passage for the flow Even in the field of actuating members, this may be desirable, with the flow of fluid through the openings even if they are not made for

change dimension.

  In the preferred arrangements, it is thanks to the fact that a tongue, tab or the like is provided.

  that we obtain more flexibility of use than pre-

  previously The range of motion of for example a

  flow control tab can be made significant

  ficative Generally, the basic element will have

  the shape of a relative sheet, plate, strip or the like

thinly.

  In general, the basic element will be in shape memory alloy and in one piece with the part

  intended to deform or to tend to deform.

  In certain aspects of the invention, it would however be

  possible that at least part of the element is reali-

  sée in another material, such as a conventional alloy.

  Such an element could be provided with a number of openings.

  tures on which are arranged tabs with

  shape welded or otherwise fixed to the base element It could be advantageous that one part of the tongue is made of shape memory alloy and another

  in another material, for example a hardened part of the

  designed to penetrate an element which must be gripped, an elastic part to constitute a seal,

  or any other material, intended to ensure other applications

  particular cations In the case where the element and the

  basic gane are at least partly of the same material, the element can be delimited by one or more slots

  practiced in the organ, in a classic way A ran-

  roughly regular slot and element can

  be desirable for certain applications.

  The characteristics and advantages of the invention

  tion will appear during the description which follows

  vre of some embodiments depicted in the

  attached sins given only as an example In the drawings: Figures 1 and 1 A show two views in

  perspective of a first embodiment, at temperatures

  different erasures; Figures 2 and 2 A show a front view of J) and a sectional view of a second embodiment; Figures 3 and 3 A show a view of

  front and a sectional view of a third embodiment

  tion; Figures 4 and 4 A show a view of

  front and a sectional view of a fourth embodiment

  tion; Figure 5 is a perspective view of a fifth embodiment; Figures 6 and 6 A show a front view and a sectional view of a sixth embodiment; Figure 7 is a perspective view of a seventh embodiment; Figures 8 and 8 A show a sectional view and a front view of an eighth embodiment;

  Figure 9 is a schematic view of a new

vth embodiment; and

  Figure 10 is a sectional view of an apparatus

  reil incorporating the embodiment of Figures 8 and 8 A. Referring to Figures 1 and 1 A, a plate 1 of shape memory alloy is shown provided

  openings 3 in the form of slots At a certain temperature

  ture, all parts of plate 4 around and between

  the parallel slots 3 are in the same plane (Figure 1).

  Thus, it can be considered that between each pair of slots Ä 7372 is defined an opening which, at this temperature, is

  covered by part of a plate At another temperature

  ture, the strip-shaped plate parts 4 located between the slots 3 bulge taking a convex shape which modifies the size and the shape of the individual slots to give the configuration of openings 2 (FIG. 1A). , the plate parts have moved apart

  openings defined above.

  The shape memory alloy plate shown

  felt in Figures 2 and 2 A has a slot 3 of

  crenellated shape, which delimits two tabs 4 and 5.

  If the tongues are subjected to an adequate treatment, the latter can curve outwards at a certain temperature by deviating from their position in the plane of the plate 1 towards a position represented in FIG. 2A, enlarging by this makes the dimension of the slots 3 to form openings 2 By bringing the temperature to its initial value, the tongues will return to their initial position, in which they extend in the plane of the plate 1 Such a change in temperature

  can be applied to the plate by a stream of fluid.

  Appropriate change in fluid temperature

  will then produce the desired tongue deformation effect-

  tes In principle, such a device can be used

  as a ventilation flap for regulating and controlling the eva-

  cuation of air for example through the openings 2 in

  depending on the air temperature.

  A similar device is shown in FIGS. 3 and 3 A However, in this case, the tongues 4 are covered by a layer 6 of flexible material containing a material capable of heating the tongues by sending an electric current thereto. By heating the tongues 4, they can go from flat to

  a curved shape An electrical insulator will be well-

  stretched interposed between the tabs and the layer of

recovery 6.

  Figures 4 and -4 A show that several or

  grooves 2 with slit-shaped parts 3 are preferably produced at regular intervals in a plate 1 made of shape memory alloy, so as to give a screening member whose screening openings have

  a variable dimension with the temperature of the plate.

  Another possibility is represented on the

  Figure 5, in which sharp incisions were made

  mant of loop-shaped parts 4 in a plate 1 of shape memory alloy This device can be used as a means of fixing or anchoring the plate to a neighboring or adjacent object 7 Such a fixing is

  performed by causing a temperature change.

  It is also possible to cover a shape memory plate with for example an elastomer layer 8 on its part provided with slots 3, as shown in FIGS. 6 and 6 A Thus, when the tongue 4 extends in the plane of plate 1, the slot is covered and

  closed by a covering part of the layer 8.

  Thanks to an appropriate temperature change, the

  ture of the slots 3 is interrupted by the deformation of the

  tab 4 Thus, the layer acts as a seal.

  Another embodiment, shown in FIG. 7, consists of a tubular fastening element 9

  fitted with tabs 4 which can be actuated thermally

  and which by suitable heating or cooling can exert a radially suitable oriented force on an element placed either inside or

  at the periphery of the tube to make a connection therewith

fixed xion.

  In the embodiments shown below

  above, the size of the openings increases and these openings

  tures are modified for example from openings 3 in the form of a slot in the plane of the plate into larger openings, the tongue 4 also extending in a direction which deviates it from the plane of the plate However, it is also possible to modify the entire shape of the plate without altering or only slightly altering the size of the openings which remain in the plane of the plate

  such an embodiment is schematic-

  ment represented in FIGS. 8 and 8 A in which a circular flat disc 1 made of shape memory alloy is deformed by heating (or cooling) suitable for assuming a convex shape (approaching a dome in a spherical cap) represented by the dotted lines During this change of shape, the width of the slots 3 decreases, but they remain in the plane of the surrounding plate 1 A combination of the two modes of transformation of the shape of the slots in

  a plate is of course conceivable.

  Referring now to the embodiment

  tion of Figure 9, there is shown a device

  ventilation for a motor vehicle radiator 10.

  The device comprises a flap plate 11 of shape memory alloy provided with openings of dimensions

  different, defined by tabs, according to the invention

  The plate 11 is zigzag and placed between the ra-

  diator 10 and a fan propeller 12 After the

  engine running, the radiator water heats up just like the space 13 behind the radiator which is delimited by the flap plate 11 When the temperature in this space 13 rises sufficiently, for example up to 55 ° C.,

  the rectangular tabs 14 delimited in the plate

  11 begin to curve backwards so as to create openings in the plate through which the flow of cooling air passing through the radiator can pass. This passage of cooling air is

  further intensified by the suction effect of the rotating blades

  propeller blades 12 When the temperature of the air stream passing through space 13 has dropped to a level

  predetermined, for example up to 45 to 50 C, the tongues-

  your plate 14 are at a temperature at which, due to their shape memory properties, they straighten up to close the openings From this moment, the air cooling action is reduced so that the temperature inside the radiator and Se the space 13 rises again When the temperature

  becomes too strong again, the tabs 14 are

  formed and the cooling cycle starts again From

  this way it is possible to control the temperature

  of the radiator within very narrow limits This

  is very desirable to maximize the rendering

  The motor flap 11 will preferably have a zigzag shape i 5 as in the drawing or a wavy shape, so as to increase its contact surface with the air current The rectangular tabs 14 are arranged so that the flow air can be carried in a roughly horizontal direction, to be able to strike with

front the radiator blades.

  A similar flap 15 can be placed in front of the radiator, however with tongues deforming backwards at around 5 ° C. to allow the cooling air to pass through the radiator. This is advantageous especially in cold weather to accelerate the engine overheating and thus minimize the time

  necessary to bring the engine to operating temperature

  In both cases, the rear side of the lan

  lookouts may possibly be covered by a flexible sealing strip 8, as has been suggested for the embodiment of FIGS. 6 and 6 A, so as to close the opening slot around the tongue when it

is in the closed position.

  A zigzag or corrugated shutter plate of 3; type just described can also be used 2 i 27372 l 1

  for example as a safety device in case of fire

  die in premises such as warehouses or large

  stores where smoke evacuation systems are born

  The shutter plate is then mounted in the roof of the room When its temperature rises sufficiently due to the fire and the development of the

  smoke in the room, the tabs start to bend

  worm thus creating smoke evacuation openings. In the embodiment of Figure 10,

  a heat sensitive clutch is illus-

  very to control a fan depending on the temperature

  surrounding temperature Temperature-controlled ventilation devices are well known, for example

  to be used on fuel-efficient truck engines

  save energy and avoid the use of a hydraulic coupling device This device comprises a rotary shaft 16 at the end of which is fixed a control member 17 with shape memory by means of a clamping ring 18 The controller 1-7 comprises a stack of slotted discs of the type shown in FIGS. 8 and 8 A and a Belleville spring 26 in the form of a disc in which a number of openings are provided 25 The slots 3 in the discs 17 are aligned with respect to each other to allow the current of air to pass through the stack The edge of the circumference

  of the disc 26 is fixed to a ring 19 having an over-

  conical outer face The fan blades are assembled

  tees on the shaft 16 by means of an element 21 and a wheel

  element 20 Element 21 is provided with a brake lining 22 When the temperature of the air flow (arrows 23) passing through the propeller is low, the control member

  has its convex shape However, when the temperature

  the air rises to a predetermined temperature (arrow

  ches 24), the discs of the control member 17 flexed

  ront and push the ring 19 axially against the gar-

  niture of brake 22 against the action of the spring

  26 Through this contact, element 21 and the blades of the

  lice 12 are coupled to the rotary shaft and begin to rotate, intensifying the evacuation of the current of hot air. When the cooling of the air flow is sufficient,

  the spring 26 pushes the discs 17 back so that they

  take their initial convex shape Element 21 and the

  ring 19 separate and the fan is no longer entering -

born by the tree 16.

Claims (8)

  1 element made of a shape memory material, characterized in that it has at least one slot (3) delimiting, at least in part, a part (4) of the element intended to deform or to tend to warp in response to a change in temperature   under the influence of the shape memory effect.   2 Flow control device, charac-   characterized in that it comprises an element according to claim 1, arranged to be placed on the path of the flow, the element having an opening (2) in which a part (4) of the element extends, this part being of a material having a shape memory and being able to move in response to a change in temperature under the influence of the shape memory effect in order to modify the flow section of the opening (2).   3 Device according to claim 2, charac-   terized in that the displacement of the part (4) is effected   kills between a position in which it is in the plane of the opening (2) and a position in which it is out of this plane.   4 Device according to claim 3, charac-   terized in that the movable part (4) is made   in one piece with the rest of the element (1) and defi- denies by at least one slot (3).   Device according to any one of claims 2, 3 and 4, characterized in that a flexible material (8) is supported by the movable part (4) for act as a seal.   6 Device according to any one of the re-   vendications 2 to 5, characterized in that the part displaces   cable (4) is provided with heating means (6).   7 Device according to any one of the re-   vendications 2 to 6, characterized in that it comprises a   regular row of openings (2) and moving outlets.   8 Device according to any one of the re-   vendications 2 _ to 7, characterized in that the element (1)   is in the form of a sheet, plate, strip or the like.   g * Elénint according to claim 1, having cores To ensure its fixation on an alut-r-zelél t, characterized in that these means include-nt said part -, 4) of il'élànent having the shape of a leg in memory of shape intended   to deform or to avzoîr teo: e to deform by comparison   oort to es es edaae e é and N response to iii change of tep ar os I in fluence of the 1 ef f and memory of formed, to cr avc another element (7).   Element according to; e ': endication 9, character-   laughed at in that said tab 4 is -one piece with the rest of the element - and defined by at least said slot (3).   he Element according to 1 any of the res-   di-cations 9 or 10, carctris o cc ui ala for 7 me   of a sheet, of a plate, of ebony or the like.   12 Cane body No. of cover plate   racté, laughed in that He correr-2 p Rs éeuse: efnts suianct la e; n-   cation 1, directed radially, ïieti-re in memory of 'i Crme arranged and adapted such as Mnanière quen o m- a car angatien of temperature, the pl-aque undergoes cu tendsuiui m ,, odificati-on of form sousl of the effect of shape memory.